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The D-26 liquid level measuring instrument LT-13 is an E+H coaxial rod guided wave radar level meter, the model is FMP40-1LL2CRJB21CA, the measuring range is 0~1700mm, the measuring medium is C5- distillation. Medium density 546.4kg/m3, operating pressure 1.0MPa(G), operating temperature 44℃. One day, the operator found that the LT-13 displayed 0mm while operating in the DCS system, called the historical trend curve of the table, and the liquid level measurement value of the LT-13 suddenly decreased from the normal value of 1102mm to a vertical state to near 0mm level. Iii. Reason analysis (A) Process inspection and analysis Process operators to the site to check the D-26 tank glass plate level meter measured value of about 1100mm. The instrument maintenance worker goes to the site to check that the display of the table transmission unit is normal and there is no fault alarm, and then the table is restored to normal after low emission treatment. Guided wave radar liquid level meter is measured according to the principle of reflected wave received after the transmitted radar wave reaches the liquid level. Because the dielectric constant of different liquids is different, the intensity of the reflected radar waves is also different. Because there is water at the bottom of D-26 tank, and the dielectric constant of water is larger than that of C5-distillate, that is, the reflected wave intensity of water is greater than that of C5-distillate, LT-13 directly measures the liquid level of water and ignores the liquid level to be measured. 1. Direct cause: the technical personnel did not dehydrate the D-26 tank in time, resulting in water at the bottom of the tank, and the process medium formed two phases of oil and water. The guided wave radar level meter directly detected the reflected wave of water, and the LT-13 showed 0mm. Indirect cause: the probe rod of guided wave radar level gauge is too long. D-26 tank level meter LT-13 outer cylinder flange spacing is 1700mm, the length of the probe rod of the liquid level meter is 1900mm, the bottom end of the probe rod extends beyond the lower flange into the bottom area of the outer cylinder. When the bottom of the tank is filled with water, the bottom of the outer cylinder is also filled with water, and it cannot be discharged through the lower flange. Management reason: the technical personnel did not drain the D-26 tank regularly according to the operating procedures. Instrument personnel installed guided wave radar level meter is not standard, did not choose the length of the probe rod according to the actual measurement range. 4. Rectification measures 1. The technical personnel should strengthen the monitoring of the liquid level of the D-26 tank water bag and drain the D-26 tank regularly. 2. Instrument personnel shorten the length of the LT-13 probe rod and ensure that the end of the probe rod is at the center of the lower flange of the outer cylinder. 1. Guided wave radar level meter is an advanced level meter commonly used in recent years. Compared with traditional float level meter and double flange level meter, it has the advantages of high measurement accuracy, small maintenance and large application range. At the same time, we can see from this case that any advanced measurement technology has certain limitations. 2, the use of any measuring instrument is closely related to the operating conditions of the process, when the process conditions or parameters change, the instrument may no longer be applicable to the current condition. 3, instrument installation status directly affects the accuracy of measurement, standard installation is crucial to the use of instruments.

Explosion-proof float level switch   Explosion-proof float level switch, also known as explosion-proof float level controller. This product is designed based on the principle of buoyancy and lever. When the liquid level in the container changes, the position of the float ball will change with the change of the liquid level. This displacement of the float ball will act on the micro-switch through the lever, and then the switch signal will be generated by the micro-switch. Application scope and features: Explosion-proof float level switch can be widely used in petroleum, chemical, electric power, metallurgy, food, pharmaceutical, paper and other industries. It can realize the brake alarm and control of the liquid level in various containers. Glass plate level gauge   The glass plate level meter is designed based on the principle of communication device. The liquid path composed of the glass plate and the main body of the level meter is connected with the measured container through the nozzle flange or taper pipe thread to form a communication device. The liquid level observed through the glass plate is the same as the liquid level in the container. The needle valve at both ends of the liquid level gauge not only plays the role of a stop valve, but the steel ball inside has the function of a check valve. When the liquid level gauge is accidentally damaged and leaked, the steel ball can automatically close the liquid channel under the action of medium pressure to prevent a large amount of liquid outflow and play a safety protection role. The liquid level meter can change the material of the parts or add some auxiliary parts to achieve anti-corrosion, heat preservation, anti-frost, lighting and other functions. Application scope and features: The glass plate level gauge has the advantages of simple structure, economical and practical, convenient installation, reliable operation and long service life. As a basic liquid level indicator, this product is widely used in the simplest liquid level measurement occasions and the degree of automation is not very high in the level measurement and monitoring of large engineering projects. Glass tube type level gauge   The liquid level meter is designed based on the principle of the communicator, which is a liquid path composed of glass tubes. The passage is connected with the measured container through the nozzle flange or taper pipe thread to form a communication device, and the liquid level observed through the glass tube is the same as the liquid level in the container, that is, the liquid level height. Tubular level gauge is mainly composed of glass tube, protective sleeve, upper and lower valves and connecting flanges (or threads). The liquid level meter can achieve the function of anti-corrosion or heat preservation by changing the material of the part or adding some auxiliary parts. Application scope and features: Tubular level meter has excellent performance (such as high temperature, high pressure, etc.). In addition, it has the advantages of simple structure, economical and practical, convenient installation, reliable operation and long service life. As a basic liquid level indicator, the liquid level gauge is widely used in the simplest liquid level measurement occasions and large-scale engineering projects with a low degree of automation. Steel tape level gauge     The steel strip liquid level gauge is a traditional liquid level gauge. It is designed and manufactured by the principle of mechanical balance. It is composed of liquid level detection device, high precision displacement transmission system, constant force device, display device, transmitter device and other peripherals. A float immersed in the liquid under test is subject to gravity W, buoyancy F, and a constant pulling force T generated by a constant force device, and when the vector sum of the three forces equals zero, the float is at a quasi-equilibrium rest. Buoyancy at mechanical equilibrium is quasi-constant (the volume V of the float immersed in the liquid is constant). When the liquid level changes, the original mechanical equilibrium will reach a new equilibrium through the movement of the steel strip under the disturbance of the float by the buoyancy. The liquid level detection device (float) drives the steel belt to move according to the liquid level, and the displacement transmission system drives the transmission pin to rotate through the movement of the steel belt, and then acts on the counter to display the liquid level. The transmitter converts this liquid level into a standard electrical signal and outputs it through the signal line. This electrical signal can drive other control devices. Application scope and features: The steel strip liquid level meter has the advantages of strong practicability, large measuring range, high precision, high performance and stability, long service life and easy maintenance. In addition, the large counter display makes the reading clear and accurate; Manual float lifting mechanism can check the working condition of the instrument at any time; Can be connected with a variety of transmitters to form a liquid level detection system. Can be widely used in petroleum, chemical, electric power, metallurgy, environmental protection, food and other industrial departments and ancillary facilities of various transmitter connection, the liquid level changes in the container into analog signals, electrical pulse signals or switching signals remote transmission to the control room display or computer room for data display and processing. Magnetic tilting column level gauge   The magnetic tilting column level meter is also called the magnetic tilting plate level meter, and its structure is mainly designed and produced based on the principle of buoyancy and magnetic force. The position of a float with a magnet (referred to as a magnetic float) in the measured medium is affected by buoyancy. The change of the liquid level leads to the change of the position of the magnetic float, and the magnetostatic coupling of the magnetic float and the magnetic turnover column (also known as the magnetic turnover plate) causes the magnetic turnover column to flip at a certain Angle (the surface of the magnetic turnover column is coated with different colors), which reflects the liquid level in the container. The electronic module and transmitter module composed of sensors (magnetic reed switches) and precision electronic components can be converted to send output resistance signals, current values (4 ~ 20mA) signals, switching signals and other electrical signals. Thus to achieve the perfect combination of field observation and remote control. Application scope and features: It has the advantages of simple structure, easy use, stable performance, long service life, easy installation and maintenance. The magnetic tilting column liquid level gauge can be applied to liquid level measurement and control in almost all kinds of industrial automation process control. It can be widely used in petroleum processing, food processing, chemical industry, water treatment, pharmaceutical, electric power, paper making, metallurgy, ships and boilers and other fields of liquid level measurement, control and monitoring. Magnetic float level meter (Level switch)   The structure of maglev ball liquid level meter (level switch) is mainly designed and produced based on the principle of buoyancy and static magnetic field. The position of the float with a magnet (referred to as the float) in the measured medium is affected by the action of buoyancy: the change in the liquid level causes the change in the position of the magnetic float. The magnet in the float and the sensor (magnetic reed switch) act to change the number of components (such as fixed resistance) of the circuit in series, and then change the electrical quantity of the instrument circuit system. That is, the change in the position of the magnetic float causes a change in the electrical quantity. The liquid level in the container is reflected by detecting the change of electrical quantity. The liquid level meter can output the resistance value signal directly, and can also use the converter module to output the current value (4 ~ 20mA) signal; At the same time with other converters, output voltage signals or switching signals (can also be according to customer demand by the company to distribute). The remote transmission, analysis and control of electrical signals are realized. Application scope and features: Magnetic float level meter can be applied to almost all kinds of industrial automation process control level measurement and control, can be widely used in petroleum processing, food processing, chemical industry, water treatment, pharmaceutical, electric power, paper making, metallurgy, ships and boilers in the field of level measurement, control and monitoring. Weight probe liquid level gauge   The heavy weight detection liquid level meter is designed and produced according to the principle of mechanical balance. When the steel strip is at rest in a certain position in the liquid, the gravity of the float, the wire rope (or the steel strip), the weight and the pointer, the buoyancy force of the steel strip and the friction force of the system are in equilibrium. When the liquid level changes, the buoyancy F will change accordingly, and the original balance of the system will be disturbed and the dynamic balance will be reached again. The change of the liquid level causes the change of the float position, and the weight drives the pointer up and down. The change of the liquid level in the container can be clearly and intuitively displayed on the scale. The top of the scale plate indicates the zero level of the liquid level, and the bottom end indicates the full scale of the liquid level. The pointer changes as the level changes, and then continuously indicates the level of the liquid level. Application scope and features: The weight detection liquid level meter has the advantages of reasonable structure design, excellent performance, reliable operation, long service life, easy installation and maintenance, and reasonable price. It can be widely used in chemical industry, electric power, water treatment and other fields of medium and large tanks of various liquids and high viscosity, corrosive liquid level continuous measurement under atmospheric pressure conditions. Ultrasonic level meter   That is, through a device that can emit energy waves (generally pulse signals), the energy wave is reflected when it encounters an obstacle, and the reflected signal is received by a receiving device. The change of level is determined according to the time difference of measuring the energy wave movement process. The microwave signal is processed by an electronic device and finally converted into an electrical signal related to the level. Once the probe transmits ultrasonic pulse signals to the surface of the measured medium, the ultrasonic wave is reflected after encountering the measured medium (obstacle) in the transmission process, and the reflected ultrasonic signal is detected by the electronic module and processed by special software. The time difference between transmitting ultrasonic wave and echo can be analyzed, and the distance of ultrasonic wave propagation can be accurately calculated by combining the propagation speed of ultrasonic wave. In turn, it can reflect the situation of the level. Application scope and features:   It can be used to automatically compensate the interference of steam, dust and moisture. In addition to liquid/solid, it can also be used for uninterruptible material/level control, tanks, storage tanks, uninterruptible material/level measurement storage rooms, granaries, etc. It is widely used in petroleum, chemical industry, tap water, sewage treatment, water conservancy and hydrology, iron and steel, coal mine, electricity, transportation and food processing industries. Intelligent radar level meter   Intelligent radar level meter is a kind of microwave level meter, which is an application of microwave (radar) positioning technology. It is transmitted through a device that can emit energy waves (generally pulse signals), the energy wave is reflected when it encounters an obstacle, and the reflected signal is received by a receiving device. The change of level is determined according to the time difference of measuring the energy wave movement process. The microwave signal is processed by an electronic device and finally converted into an electrical signal related to the level. In microwave level measurement equipment, the energy wave used is usually a high-frequency electromagnetic wave with a frequency of 8.3GHz (mostly around 6GHz, but there are higher frequencies). The energy waves used by the device are pulsed energy waves. The maximum pulse energy of the general pulse energy wave is about 1mW (the average power is about 1μW), and it will not cause radiation damage to other equipment and personnel. Scope of application: The intelligent radar level level meter is used for non-contact continuous measurement of the level of liquids, slurries and particles. It is suitable for occasions where the temperature and pressure change greatly and there is inert gas or steam. It adopts the measurement method of microwave pulse (PTOF) and can work normally in the range of industrial frequency bands. Beam energy is low, can be installed in a variety of metal, non-metal containers or pipelines, no harm to the human body and the environment. Features:   1, no blind area, high precision 2, two-wire technology, is the differential pressure instrument, magnetostriction, RF admittance, magnetic flap instrument excellent alternative products. 3, free from pressure changes, vacuum, temperature changes, inert gas, smoke, steam and other environmental impact 4, easy installation, strong and durable, maintenment-free 5, the output signal is 4mA ~ 20mA/HART protocol, simple calibration, easy to achieve on-site calibration operation through digital liquid crystal display, through the software to achieve simple configuration setting and programming 6, sensitive measurement, Refresh speed is fast. 7, suitable for high temperature conditions, up to 200℃ process temperature, when using high temperature extension antenna up to 350℃. Capacitive level meter   The measuring principle of the capacitive level meter shows that the oscillation frequency of the oscillating circuit is related to the capacitance value, and the change of the level causes the change of the system capacitance, and then changes the oscillation frequency of the oscillating circuit. The oscillating circuit in the sensor can convert the capacitance change caused by the level change into the frequency change, and send it to the electronic module, and then convert it into the engineering quantity after calculation and analysis processing, so as to realize the continuous measurement of the level. The instrument is made using advanced technology and production processes and consists of sensors, secondary instruments and other accessories. The sensor is placed on the top of the silo, the probe is inserted vertically into the silo, and the secondary instrument is placed in other suitable places. The sensor converts the change of level into the corresponding electrical pulse signal, which is transmitted to the secondary instrument to process and display the level height, and has high/low alarm and low alarm. 4 to 20mA. Transfer output for liquid/solid material crop height display, alarm, control and remote display or composition systems.   Application scope and features:   The liquid level gauge has the advantages of simple structure, convenient installation and reliable performance; At the same time, the electrode is made of stainless steel material, strong corrosion resistance, insulation and conductive materials can be used, and the maintenance amount is small. The liquid level gauge can be widely used in petroleum, chemical, electric power, metallurgy, food, environmental protection and other industrial sectors to monitor the level of open or pressurized vessels. However, the liquid level meter is not suitable for occasions where the dielectric constant or material humidity changes too much and the solid medium where the material particles are greater than 15mm and cannot be in good contact with the electrode. Magnetostrictive level meter     The working principle of magnetostrictive liquid level sensor: An initial pulse is generated by the electronic circuit in the electron bin. When the initial pulse is transmitted in the waveguide wire, a rotating magnetic field advancing along the direction of the waveguide wire is generated. When the magnetic field meets the permanent magnetic field in the magnetic ring or float, a magnetostrictive effect is generated, which causes the waveguide wire to twist. This twist is sensed by the pickup energy mechanism installed in the electronic bin and converted into the corresponding current pulse, and the time difference between the two pulses can be calculated through the electronic circuit, and the displacement and liquid level can be accurately measured.   Application scope and features: The product has the advantages of high precision, good stability, high reliability, diverse output signals, long service life, safety and reliability. Widely used in industrial process control, oil processing, pharmaceutical, food processing, water treatment, gas station underground inventory in the field of liquid level, temperature, density, interface and other physical parameters monitoring, alarm and control.

Radar level meter is a common product type of level instrument, which has the advantages of accurate measurement, stable performance, high reliability, easy maintenance and wide application range. It can be installed in various metal and non-metal containers or tanks to measure the level of liquid, slurry and particles. So, what special conditions will it be installed in? 1. Selection under stirring condition In the stirred tank, generally do not use the guided wave radar level gauge, the force brought by stirring, it is easy to bring the guided wave radar cable into the stirring device, or the rod guided wave radar rod to pull the bend. Therefore, it is only possible to choose non-contact measurement of frequency modulation or high-frequency horn radar level meter to measure. 2. Selection under vacuum conditions Under vacuum conditions, the boiling point of a liquid will be much lower than at standard atmospheric pressure. There are a lot of liquids that start boiling at 30-40 degrees Celsius. Especially the reaction kettle and evaporation kettle, when there is no vacuum, the liquid is very calm, the vacuum is pumped, the liquid level fluctuates greatly, and it is boiling foam and small water beads. In this case, only the non-contact radar can be used, and then certain changes must be made on site to make it work normally. Third, the medium contains a lot of foam, water steam, dust selection Generally there are a variety of forms of media, most of them are liquid, we generally recommend to choose the frequency modulation radar level meter measurement, its operating frequency has the electromagnetic characteristics of terahertz band, such as: has the ability to penetrate non-polar substances, in the strong adhesion strong dust industrial environment, has a very ideal measurement stability and environmental anti-interference ability; For strong dust conditions, we can add a universal joint to adjust the measurement direction, with purging function, in order to prevent measurement errors. 4. Selection of operating temperature above 200℃ Radar level meter generally operating temperature of -40℃-150℃. However, under high temperature conditions, we must choose a high temperature radar level meter to ensure that the radar level meter can work normally. The application range of radar level meter is very wide, across the electric power, medicine, steel, metallurgy, cement, petrochemical, paper, food and other fields, but the application of different working conditions, the type of radar level meter choice is also very important. What do you need to pay attention to when using radar level meter? 1. If the radar level meter is used outdoors and the LCD screen is aging in order to avoid long-term exposure to sunlight, it is recommended to install an awning or protective box for the meter. 2. If the radar level meter is used in the occasion of corrosive gases or liquids, or is used at the seaside or sea, the anti-corrosion radar level meter should be selected. In addition, if the instrument is used in an environment with corrosive gases, in order to avoid corrosion of the instrument, it should also be equipped with an anti-corrosion jacket. 3. If the radar level meter is used in a particularly hot and cold place, because the ambient temperature may exceed the working requirements of the instrument, in order to ensure the normal operation of the instrument, it is recommended to add a thermostat around the instrument. 4. If the radar level meter is used in the lightning frequent area, although the meter itself has a lightning protection device, for safety reasons, it is recommended to install a special lightning protection device at the inlet and outlet end of the radar level meter.   5. When using the radar level meter, pay attention to installing protective tubes for wires and cables to prevent water and rodents from biting. 6. When using the radar level gauge, care should be taken to keep the radar level gauge perpendicular to the measured liquid level, and ensure that there are no other obstacles within the conical range of the radar wave emission. 7. If the radar level meter is used in the environment of dust, steam, fog, liquid surface foam, floating matter, liquid stirring, wave, etc., please pay attention to the special selection of radar level meter! According to different working conditions and complex environments, these factors increase the difficulty of accurate measurement of radar level meter, so it is recommended to consult professional and technical personnel of radar level meter in selection!

Liquid level meter is one of the common components of the equipment, today we will understand the liquid level meter together. The types of commonly used level meters are as follows: First, the main principle of the magnetic flip plate level meter: The magnetic flip plate level meter is also called the magnetic flip column level meter, the structure is mainly based on the principle of buoyancy and magnetic design and production of the float with a magnet (referred to as the magnetic float) in the measured medium is affected by the effect of buoyancy. The change of liquid level leads to the change of the position of the magnetic float, and the magnetostatic coupling between the magnetic float and the magnetic turnover column (also known as the magnetic turnover plate) causes the magnetic turnover column to flip at a certain Angle (the surface of the magnetic turnover column is coated with different colors) to reflect the liquid level in the container. The main principle of magnetic float level meter (liquid level switch) : The structure of magnetic float level meter (liquid level switch) is mainly based on the principle of buoyancy and static magnetic field design and production of float ball (referred to as float ball) in the measured medium is affected by the effect of buoyancy: the change of liquid level leads to the change of magnetic float position. The magnet in the float and the sensor (magnetic reed switch) act to change the number of components (such as fixed resistance) of the circuit in series, and then change the electrical quantity of the instrument circuit system. That is, the change in the position of the magnetic float causes a change in the electrical quantity. The liquid level in the container is reflected by detecting the change of electrical quantity. The main principle of explosion-proof float level switch: explosion-proof float level switch, also known as explosion-proof float level controller. Specially designed and manufactured for use in explosive environment liquid level control instrument, this product is based on the principle of buoyancy and lever design when the liquid level in the container changes, the position of the float ball will change with the change of the liquid level, this displacement of the float ball will act on the micro switch through the lever, and then the switch signal will be generated by the micro switch. Four, the working principle and structure of the glass plate liquid level meter: the liquid level meter is designed based on the principle of the glass plate and the liquid path composed of the main body of the liquid level meter is connected with the measured container through the nozzle flange or taper pipe thread to form a communication device, through the glass plate to observe the liquid level and the liquid level in the container is the same, that is, the level height. The needle valve at both ends of the liquid level gauge not only plays the role of a stop valve, but the steel ball inside has the function of a check valve. When the liquid level gauge is accidentally damaged and leaked, the steel ball can automatically close the liquid channel under the action of medium pressure to prevent a large amount of liquid outflow and play a safe maintenance role. The liquid level meter can change the data of the parts or add some auxiliary parts to achieve anti-corrosion, heat preservation, anti-frost, lighting and other functions. Working principle and structure of the glass tube type liquid level meter: The liquid level meter is a liquid path composed of glass tubes designed based on the principle of the communication device. The passage is connected with the measured container through the nozzle flange or taper pipe thread to form a communication device, and the liquid level observed through the glass tube is the same as the liquid level in the container, that is, the liquid level height. The tubular level gauge is mainly composed of glass tubes, maintenance sleeves, upper and lower valves and connecting flanges (or threads). The liquid level meter changes the data of the parts or adds some auxiliary parts to achieve the function of anti-corrosion or heat preservation. Six, the working principle of the steel strip liquid level meter: The steel strip liquid level meter is a traditional liquid level meter. Using the principle of mechanical balance design and production of liquid level detection device, high precision displacement transmission system, constant force device, display device, transmitter device and other peripheral components. The main principle of the heavy weight detection liquid level meter: The heavy weight detection liquid level meter is designed and produced according to the principle of mechanical balance. When the steel strip is submerged and floating in a certain position in the liquid, the gravity of the float, the steel wire rope (or the steel strip) weight and the pointer, the buoyancy of the steel strip by the liquid and the system friction are in balance. Eight, ultrasonic level meter working principle: the working principle of this product: through a can emit energy waves (generally pulse signals) device to emit energy waves, energy waves encountered obstacles reflected by a receiving device to receive the reflected signal. The change of material level is determined according to the time difference of measuring the energy wave movement process. The microwave signal is processed by an electronic device and finally converted into an electrical signal related to the level. Once the probe transmits ultrasonic pulse signal to the surface of the measured medium, the ultrasonic wave is reflected after encountering the measured medium (obstacle) in the transmission process, and the reflected ultrasonic signal is detected by the electronic module and processed by special software. The time difference between transmitting ultrasonic wave and echo can be analyzed, and the distance of ultrasonic wave propagation can be accurately calculated by combining the transmission speed of ultrasonic wave. In turn, it can reflect the situation of the level. Nine, the main principle of intelligent radar level meter: Intelligent radar level meter is a microwave level meter, an application of microwave (radar) positioning technology. The energy wave is transmitted through a device that can transmit energy waves (generally pulse signals), and the energy wave is reflected when it encounters an obstacle, and the reflected signal is received by a receiving device. The change of material level is determined according to the time difference of measuring the energy wave movement process. The microwave signal is processed by an electronic device and finally converted into an electrical signal related to the level. 10, guided wave radar level meter working principle: guided wave radar level meter is a microwave level meter, an application of microwave (radar) positioning technology. The energy wave is transmitted through a device that can transmit energy waves (generally pulse signals), the energy wave is transmitted in the waveguide, the energy wave is reflected when it meets an obstacle, and the reflected energy wave is transmitted by the waveguide to the receiving device, and the receiving device receives the reflected signal. The change of material level is determined according to the time difference of measuring the energy wave movement process. The microwave signal is processed by an electronic device and finally converted into an electrical signal related to the level. 11. Working principle of capacitive level meter: Measurement principle of capacitive level meter, oscillation frequency of oscillation circuit is related to capacitance value, the change of level causes the change of system capacitance, and then changes the oscillation frequency of oscillation circuit. The oscillating circuit in the sensor can convert the capacitance change caused by the change of level into the change of frequency, and send it to the electronic module, and then convert it into the engineering quantity after calculation and analysis, so as to realize the continuous measurement of level. 12, RF admittance level controller working principle: RF admittance level controller is a new level measuring instrument designed and produced by using RF admittance level control technology. Radio frequency admittance measurement technology, simply said is the use of high frequency current measurement system admittance method. Different from capacitance technology, three-terminal technology is adopted in point-position RF admittance technology, which makes the measurement parameters diversified. Radio-frequency admittance technology introduces measurement parameters except capacitance, especially resistance parameters, so that the signal-to-noise ratio of the measurement signal is improved, and the resolution, accuracy and reliability of the instrument are greatly improved. The diversity of measurement parameters also effectively expands the reliable application field of the instrument. The level control technology that makes the product anti-hanging material (the material that the sensor adheres to is called the hanging material) better performance, more reliable work, more accurate measurement and wider applicability. 13, tuning fork level controller working principle: tuning fork level controller is a new type of level switch. The induction rod base of the tuning fork level switch is designed and made by using the principle of tuning fork vibration. The tuning fork rod is driven by piezoelectric wafer, and the vibration signal is received by another piezoelectric wafer, so that the vibration signal is circulated and the induction rod resonates. When the material is in contact with the induction rod, the vibration signal gradually becomes smaller until the resonance stops, and the control circuit will output the electrical contact signal. Due to the natural principle that the sensitivity of the induction rod decreases from the front to the back seat, no error signal will occur when the material in the tank and around the barrel pile up, touch the induction rod base < rear > or discharge material. 14. Working principle of magnetostrictive level meter: Working principle of magnetostrictive level sensor: An initial pulse occurs from the electronic circuit in the electron bin. When the initial pulse is transmitted in the waveguide wire, a rotating magnetic field advancing along the direction of the waveguide wire occurs. When the magnetic field meets the permanent magnetic field in the magnetic ring or float, a magnetostrictive effect occurs, causing the waveguide wire to twist. This twist is sensed by the pickup energy mechanism installed in the electronic bin and converted into the corresponding current pulse, and the time difference between the two pulses can be calculated through the electronic circuit, and the displacement and liquid level can be accurately measured.

Radar level gauge Principle: Emission - reflection - receiving is the basic working principle of radar level meter. The antenna of the radar sensor transmits the electromagnetic wave signal in the form of a beam. The transmitted wave reflects on the surface of the measured material, and the reflected echo signal is still received by the antenna. Each point of the transmitted and reflected beam is collected by ultrasonic sampling. After the signal is processed by the intelligent processor, the distance between the medium and the probe is obtained, and the terminal display is sent for display, alarm, operation, etc. Features: The biggest feature of the radar level meter is that it has significant effect under harsh conditions. Whether it is toxic media, or corrosive media, whether it is solid, liquid or dusty, slurry media, it can be measured. In terms of measurement, it has the following characteristics: 1, continuous and accurate measurement The probe of the radar level meter has no contact with the surface of the medium, which is a non-contact measurement, and can accurately and quickly measure different media. The probe is almost unaffected by temperature, pressure, gas, etc. (only 0.018% at 500 ° C and 0.8% at 50bar). 2. It has suppression function for interference echo 3, accurate and safe energy saving The chemical and mechanical properties of the material used in the radar level meter are quite stable, and the material can be recycled, which has great environmental protection effect. 4, no maintenance and strong reliability Microwaves are almost free from interference and are not in direct contact with the measuring medium, and can almost be applied to a variety of occasions, such as vacuum measurement, liquid level measurement or material level measurement. Due to the use of advanced materials, it is very durable for extremely complex chemical and physical conditions, and it can provide accurate and reliable, long-term stable analog or digital level signals. 5, easy maintenance, simple operation Radar level meter has fault alarm and self-diagnosis function. Analyze the fault according to the error code prompted by the operation display module, determine the fault and eliminate it in time, make the maintenance and correction more convenient and accurate, and ensure the normal operation of the instrument. 6, wide range of application, can measure almost all media From the shape of tank body, the radar level meter can measure the liquid level of spherical tank, horizontal tank, cylindrical tank, cylindrical cone tank, etc. From the function of tank, the liquid level in storage tank, buffer tank, microwave tube and bypass tube can be measured. From the measured medium, liquid, particle, slurry, etc., can be measured. Summary: In general, the radar level meter has a wide range of use and is a non-contact measurement method. Excellent material, low failure rate. Guided wave radar level gauge Principle: Guided wave radar level meter is a measuring instrument based on the principle of time travel. Radar waves run at the speed of light, and the running time can be converted into level signals through electronic components. The probe emits a high-frequency pulse that travels along the cable probe, and when the pulse hits the surface of the material, it is reflected back to be received by the receiver inside the meter, and the distance signal is converted into a level signal. peculiarity 1, the steam and foam have a strong inhibition ability, the measurement is not affected; 2, not affected by the density of liquid, the degree of porosity of solid materials, temperature, dust during feeding; 3, low maintenance, high performance, high precision, high reliability, long service life. Is there a difference? The contact mode is different: the radar level meter is non-contact, and the waveguide level meter is contact. That is to say, in the case of higher food grade requirements, pilot type can not be used. Different working conditions of the medium: guided wave radar type level meter needs to consider the corrosion and adhesion of the medium, and too long guided wave radar installation and maintenance is more difficult. Under the condition of low dielectric constant, the measurement principle of both radar and guided wave radar is based on the difference in dielectric constant. Since the emitted waves of ordinary radar are diverging, when the dielectric constant is too low, the signal is too weak and the measurement is unstable, while guided wave radar waves propagate along the guide pole and the signal is relatively stable. In addition, general guided wave radar also has the function of bottom detection. It can be modified according to the measured value of the bottom echo signal, so that the signal is more stable and accurate. The selection is different: ordinary radar can be used interchangeably, and guided wave radar can not be used interchangeably because the length of the guide rod (cable) is fixed according to the original working condition, and the selection of guided wave radar is more troublesome than ordinary radar. The measurement range is different: ordinary radar is more common in the application of 30, 40m tanks, and even 60m can be measured. Guided wave radar should also consider the stress of the wave guide rod (cable), which is also due to the reason of stress, the measurement distance of guided wave radar is generally not very long. However, guided wave radar has obvious advantages in some special working conditions, such as stirring in the tank and large medium fluctuation, the measured value of guided wave radar with fixed bottom in such working conditions is more stable than that of flexible radar; There is also the level measurement in the small tank, due to the small installation measurement space (or more interference in the tank), the ordinary radar is generally not applicable, then the advantages of guided wave radar appear.

Radar level meter is a common product type of level instrument, which has the advantages of accurate measurement, stable performance, high reliability, easy maintenance and wide application range. It can be installed in various metal and non-metal containers or tanks to measure the level of liquid, slurry and particles. So, what special conditions will it be installed in? 1 In the case of stirring selection in the stirred tank, generally do not choose the guided wave radar level meter, the force brought by stirring, it is easy to bring the guided wave radar cable into the stirring device, or the rod guided wave radar rod to pull the bend. Therefore, it is only possible to choose non-contact measurement of frequency modulation or high-frequency horn radar level meter to measure. 2 Selection under vacuum conditions Under vacuum conditions, the boiling point of the liquid will be much lower than the standard atmospheric pressure. There are a lot of liquids that start boiling at 30-40 degrees Celsius. Especially the reaction kettle and evaporation kettle, when there is no vacuum, the liquid is very calm, the vacuum is pumped, the liquid level fluctuates greatly, and it is boiling foam and small water beads. In this case, only the non-contact radar can be used, and then certain changes must be made on site to make it work normally. 3 Media containing a large number of foam, water vapor, dust selection there are generally a variety of forms of media, most of them are liquid, we generally recommend to choose frequency modulation radar level meter measurement, its operating frequency has terahertz band electromagnetic characteristics, such as: It has the ability to penetrate non-polar substances, and has ideal measurement stability and environmental anti-interference ability in the industrial environment with strong adhesion and strong dust. For strong dust conditions, we can add a universal joint to adjust the measurement direction, with purging function, in order to prevent measurement errors. 4. The general working temperature of the selection above 200℃ is -40℃-150℃. However, under high temperature conditions, we must choose a high temperature radar level meter to ensure that the radar level meter can work normally. 5 Selection parameters ● Installation position opening position, distance from tank wall, inlet/outlet position, short nozzle size and length, whether there is a cut-off valve (gate valve or ball valve) on the short nozzle; ● Tank structure Tank structure and shape (conical tank, spherical tank, reaction kettle, horizontal tank, silo), tank height and diameter, whether there is a wave guide tube and the diameter of the wave guide tube in the tank, the material of the tank lining, whether there is a heating coil in the tank, whether there is an internal floating roof in the tank, and whether there are other obstacles in the tank; ● Measuring dielectric liquid: dielectric constant, foam, corrosion, steam, crystallization, medium viscosity, temperature, pressure, liquid level fluctuation; Solid: dielectric constant, dust, pile Angle, inlet and outlet speed, whether it can be universal purging; ● Connection mode flange size, nominal pressure, sealing surface requirements, whether with matching flange; ● Power requirement 24V/220V; ● Signal output requirements 4-20mA or RS-485● Electrical interface requirements size: M20*1.5, 1/2NPT, etc. ● Whether there is stirring in the reactor, several layers of stirring, how far the stirring fan is from the tank wall, and the speed of the agitator; ● Power supply environment Whether the on-site power supply is a separate power supply, whether the signal cable is separated from the high-voltage cable, and whether there is interference from high-power electrical equipment around.

In industrial automation, accurate level measurement is essential for process control and safety. Radar and ultrasonic level gauges are the two most commonly used technologies. Each technology has its own unique advantages, but understanding their differences, as well as the applicable scenarios, is crucial to choosing the right instrument. This paper will make a detailed comparison of these two technologies, and analyze their technical characteristics, working principles and application scenarios.     1. How it works     The radar level meter transmits a microwave signal that passes through the air and reflects back when it hits a material surface. The meter calculates the distance of the material by measuring the time difference between the transmission and reception of the signal. Radar level gauges typically operate in the high frequency range, which can range from 6 GHz to 80 GHz, depending on the model and application. Ultrasonic level gauges work with sound waves, usually transmitting at frequencies between 20 and 200 kHz. The measurement principle is similar to radar, and the distance is determined by the time difference after the sound wave reaches the surface of the material and reflects back.     2. Environmental adaptability   One of the key factors in choosing a radar or ultrasonic level gauge is the environmental conditions. Radar level gauge is not affected by temperature, pressure changes or field dust, steam, foam, etc. This makes it ideal for use in harsh environments with high temperature, high pressure and a lot of dust, such as chemical plants or mining industries (Zhou et al., 2022). Although the ultrasonic level meter is low in cost, it is more sensitive to environmental conditions. Temperature fluctuations can affect the propagation speed of sound waves, resulting in measurement errors. In addition, in environments where there is a large amount of steam, foam, or dust, the propagation of ultrasonic waves can be disturbed, affecting the stability of the measurement (Smith & Johnson, 2021).   3. Accuracy and range   Radar level gauges generally have higher accuracy, with measurement errors as low as ±1 mm, especially in high-frequency models. In addition, radar level gauges can have a measuring range of more than 80 meters and are suitable for tall silos or large storage tanks (Miller, 2020).   The accuracy of the ultrasonic level meter is relatively low, and the measurement range is usually within 30 meters, which is suitable for small to medium-sized tanks. In the presence of strong turbulence or dust environment, its measurement performance will be degraded.   4. Cost and complexity   Ultrasonic level meters are favored because of their simple structure and low cost. They are easy to install and maintain, and are suitable for simple application scenarios with relatively stable environmental conditions. However, in harsh environments, its long-term reliability may be affected, which may increase maintenance costs later. The ultrasonic level meter is easy to install and maintain, and is suitable for simple application scenarios with relatively stable environmental conditions Although the initial cost of radar level meters is high, its application flexibility and high reliability in complex environments make it less expensive to maintain in the long run. Especially in scenarios where frequent maintenance and calibration are not required, radar level gauges are more economical (Chen et al., 2021).   5. Industrial applications   The radar level gauge is especially suitable for industrial fields such as petroleum, chemical, mining, etc., which require accurate and reliable measurement. They maintain stable measurement performance under high pressure, high temperature environments, and in the presence of large amounts of dust. The radar level gauge is especially suitable for industrial fields such as petroleum, chemical and mining, which require accurate and reliable measurement Ultrasonic level meter is more suitable for non-pressurized tanks, water treatment facilities and other environmental conditions are relatively simple scenes. Due to its non-invasive measurement characteristics, ultrasonic level meters are also widely used in the food and beverage industry.   6. Conclusion   Radar and ultrasonic level meter have their own unique application scenarios. For harsh environments or occasions where high precision and long distance measurements are required, radar level gauges are undoubtedly a better choice. In less demanding scenarios, ultrasonic level gauges provide a more cost-effective solution. Ultimately, selecting the right level measurement technology requires understanding the advantages and limitations of each technology based on the specific application requirements to ensure the best measurement results in industrial processes.

The working principle of the radar level meter is similar to that of the radar system, also known as the principle of radio wave reflection. When the radar level meter emits electromagnetic waves, the electromagnetic waves will be reflected by the liquid level surface, part of the electromagnetic waves will be reflected back, and the other part will penetrate the liquid level. These reflected electromagnetic waves are received by the receiver and the liquid level height is calculated by the relative position of the transmitter and receiver. Photo source: Baidu Pictures Radar level meter parameter Settings are similar, this article is for reference only. 2. Basic Parameter setting 1. Open the table cover and press "Ok" to enter the setting menu. 2. Select Basic Settings and press OK to enter basic Settings. 3. The application type is selected according to the actual measurement medium. In this case, the liquid level of the sink is measured, so "liquid" is selected. 4, container type select "demonstration", demonstration response speed is the fastest. Can also be selected according to the actual container. 5. Set the dielectric constant of the measuring medium. 6. Set the high and low bits. 7, the blind area set 0.3m. 8. The range is set at 5.0m. 9. Set the damping time to 5s. 10. The sensor mode is set to "level". 3, Professional Settings 1, in the menu Settings page, select "professional Settings". 2. Select "False echo Learning". 3, false echo mode, select "select area". 4, "false echo area" data unchanged, directly press "Ok" to enter the next step. 5. Go to the "false echo Learning" page, select "Clear zero" and press "OK". If OK is displayed, clear zero is complete. 6. Select "New" and press "OK" to create a false echo. If OK is displayed, the new echo is created successfully. 7. Press "BK" to return to the display page. 1, instrument simulation: select "Current simulation" in "Professional Settings", you can perform 4-20mA current output simulation. 2, communication function: Modbus communication, Hart communication parameters set in the "bus address" set.

The installation requirements of the glass plate (tube) level meter are as follows: 1. When the glass plate (tube) level meter and the float (float) level meter are used to measure the same liquid, the measuring range of the glass plate (tube) level meter should include the measuring range of the float (float) level meter. 2, when several liquid level gauges are used together, the two adjacent liquid level gauges should overlap 150~250mm in the vertical direction, and the horizontal spacing should be 200mm. 3. When several liquid level gauges are used in combination, an external connecting pipe should be installed. Both ends of the connecting pipe should be equipped with a cutting valve.       Second, the installation requirements of the external float level gauge are as follows:   1. Both ends of the liquid level gauge should be equipped with cut-off valves. 2, the middle position of the measuring range of the liquid level meter. 3, the top and bottom flange type liquid level meter, the upper and lower instrument connecting head (nozzle) spacing should be at least 500mm more than the measuring range.       Third, the installation requirements of the internal float level gauge are as follows: 1, the normal liquid level should be in the middle of the buoy. 2. When the liquid level fluctuates greatly, the anti-wave tube should be added.     Fourth, the installation requirements of the internal float level meter are as follows: 1, the horizontal center line of the liquid level meter mounting flange should be consistent with the normal liquid level. 2, there should be no obstacles in the range of float activities, and the anti-impact plate should be added in the case of large logistics impact.       Five, the installation requirements of the magnetostrictive liquid level meter are as follows: 1, the magnetostrictive level meter should be installed on the top of the container or the top of the connecting pipe drawn from the side of the container. 2. The magnetostrictive level meter installed on the top of the arch tank or the spherical tank should be flanged, and the inner diameter of the flange type instrument connector (tube nozzle) should be greater than the float diameter. 3. When installed on the connecting pipe outside the container, the inner diameter of the connecting pipe should be greater than the outer diameter of the float, and the connecting pipe should be made of non-magnetic materials (such as stainless steel, aluminum or alloy).       Six, ultrasonic and microwave (radar) liquid (material) level meter installation requirements are as follows:   1, the occasion of measuring liquid level, should be vertically downward detection and installation. 2. In the event of measuring the material level, the ultrasonic or microwave beam should point to the discharge port at the bottom of the silo. 3, ultrasonic or microwave beam center distance from the container wall should be greater than the beam Angle, measurement range calculated by the lowest liquid (material) location of the beam radius. 4, ultrasonic or microwave beam path should avoid the container feed beam injection range. 5, ultrasonic or microwave beam path should avoid stirrer and other obstacles. 6, ultrasonic or microwave liquid (material) level meter installation, should also meet the requirements of the manufacturer.       7. The installation of guided wave radar and capacitive level meter shall meet the following requirements:   1, the level meter should be installed on the top of the storage tank to avoid collision with the moving parts in the equipment; When the medium in the equipment fluctuates violently, the wave guide rod (probe) should be fixed with a perforated protective tube. 2. When the liquid level gauge is installed on the external connecting pipe of the equipment, the following provisions should be met :a) the length of the wave guide rod (probe) should include the upper and lower measuring dead zones, and the end should be at least 50mm lower than the center of the connecting port of the lower part of the connecting pipe; b) When using a guided wave radar level meter with a two-rod probe, the diameter of the connecting tube is not less than 80mm; When the guided wave radar level meter with a single rod probe is used, the diameter of the connecting tube shall not be less than 50mm. 3. When measuring large liquid level with cable probe type guided wave radar, the cable probe should be straightened and fixed at the bottom of the equipment, and the perforated protective tube should be fixed when the liquid level fluctuates sharply. 4. When the temperature of the measured medium is high, the transmitter should be separated and installed. 5, guided wave radar and capacitive level meter installation should also meet the requirements of the manufacturer.       8. The installation of static pressure level measuring instruments shall comply with the following provisions:   1. The distance between the instrument connector (nozzle) and the bottom of the tank should be greater than 300mm, and it is in an orientation that is easy to maintain. 2, the installation height of the double flange remote transmission differential pressure level meter should not be higher than the lower pressure flange port on the container, and accurately calculate the zero point and negative migration: the conduction capillary should be fixed by Angle steel or steel pipe, and the place where the ambient temperature changes greatly should take insulation measures. 3, the installation of the differential pressure transmitter to measure the liquid level should meet the following requirements :a) The distance between the upper and lower pressure instrument connection head (nozzle) should be greater than the required measurement range; The distance between the lower pressure instrument connector (tube nozzle) and the bottom of the tank is not less than 200mm, and avoid the liquid pumping outlet: the upper pressure instrument connector (tube nozzle) should avoid the gas phase injection inlet, and if it cannot be avoided, anti-impact measures should be taken; b) When measuring the liquid level of volatile or condensable medium, isolation tanks should be added on the negative pressure side (gas phase) or on both sides of the positive and negative pressure, and the zero point and negative migration amount should be accurately calculated; c) When measuring the liquid level of the steam boiler drum, the temperature self-compensation balance vessel should be installed, and the pressure guide pipe should be heat tracing and heat insulation. 4. When using the insert type reverse blowing method to measure the liquid level, the end of the insert pressure guide tube should be at least 200mm away from the bottom of the tank, and cut into a slope shape.

In the sewage treatment system using automatic control, in addition to measuring the level meter, many also involve the start and stop of the interlocking pump in the automatic control and the opening and closing of the control valve. The proper selection of the liquid level gauge plays a very important role in reasonably meeting the requirements of the process. First, the principle of magnetic turnover liquid level meter: The liquid level meter works according to the principle of buoyancy and the principle of magnetic coupling. When the liquid level in the measured container rises and falls, the float in the main tube of the liquid level gauge also rises and falls, and the magnetic steel in the float is transferred to the field indicator through magnetic coupling, driving the red and white tilting column to turn over 180°. When the liquid level rises, the tilting column turns from white to red, and when the liquid level drops, the tilting column turns from red to white. The red and white boundaries of the indicator are the actual height of the medium liquid level in the container, so as to realize the indication of the liquid level. Characteristics of magnetic turnover level meter: (1) Simple structure, clear display, intuitive reading, especially suitable for field display. (2) The equipment has few holes, and the magnetic turnover level meter with remote output is generally selected, so that on-site and remote monitoring can be carried out. (3) According to the condition of the medium, such as the easily polluted and easily blocked medium, it is necessary to regularly clean the main pipe and remove the sediment in the pipe to ensure the accuracy of the measurement. In the sewage treatment process, the magnetic turnover liquid level meter is often used for the measurement of liquid level of chemical dissolving tank, acid tank, alkali tank, etc. Second, ultrasonic level meter Ultrasonic level meter is the use of ultrasonic reflection principle at the liquid level of the liquid level separation detection, that is, the application of echo measurement distance principle. When the ultrasonic probe sends a short ultrasonic pulse to the liquid surface, after time t, the probe receives the echo pulse reflected back from the liquid surface. Therefore, the distance from the probe to the liquid surface can be calculated according to the formula: set the distance from the ultrasonic probe to the bottom of the container to h, then the actual liquid level. In the formula, v is the speed of ultrasonic propagation in the measured medium (that is, the speed of sound m/s), it can be seen that as long as the sound speed v is known, the height of the liquid level H can be obtained by accurately measuring the time t. Ultrasonic level meter features: (1) The ultrasonic level meter can be non-contact measurement, stable and reliable operation: the ultrasonic level meter is installed above the silo and liquid tank, and does not directly contact the material, overcoming the disadvantages caused by the direct contact with the material of other types of liquid (material) level meter. (2) Can be measured in a large range, liquid, block, powder level can be measured. (3) can be fixed point continuous measurement, and can easily provide telemetry and remote control measurement signals. (4) Installation is simple and convenient, and does not require safety protection. Disadvantages of ultrasonic level meter: (1) Ultrasonic liquid level meter measurement will have a blind area, the installation needs to avoid the blind area, when the liquid level into the blind area, the ultrasonic transmitter can not measure the liquid level, so in determining the ultrasonic liquid level meter range, must set aside the margin of the blind area, installation, the transmitter probe must be higher than the highest liquid level blind area. In this way, we can ensure the accurate monitoring of the liquid level and ensure the safety of the ultrasonic level meter. (2) In the case of foam, because the sound wave cannot penetrate the foam, the sound wave will be reflected back on the foam, so that the measurement has a large deviation from the actual liquid level. Defoamer can be added to the tank container with foam to reduce foam generation and ensure accurate measurement. (3) The ultrasonic level meter will be affected by the stirrer in the container with a stirrer, causing the reflection of false reflection echoes, resulting in inaccurate measurement. By reducing the speed of the mixer and leaving the center of the mixer when installing the level meter, the influence of the mixer on the ultrasonic level meter measurement can be reduced. (4) The temperature of the measuring medium also has an impact on the ultrasonic level meter, especially in a closed container, when the temperature of the medium has a temperature difference with the surrounding temperature, there will be condensation around the probe, which will affect the accuracy of the measurement. When installing the ultrasonic level meter, the compressed air tube can be blown against the probe to reduce the influence of condensation on the measurement because of the temperature difference between the medium and the container and the probe. The static pressure type liquid level measurement method is based on the principle that the static pressure of the liquid column is proportional to the height of the liquid column, and the liquid level measurement is achieved by measuring the static pressure generated by the height of the liquid column. The differential pressure type liquid level meter works by using the principle that when the liquid level in the container changes, the static pressure generated by the liquid column also changes accordingly. The static pressure type liquid level meter is to measure the liquid level by measuring the static pressure generated by the liquid level height. According to P=ρgh, and the density of the liquid ρ, the acceleration of gravity g is known, as long as the pressure P is measured, the liquid level h can be found. One kind of pressure meter for liquid level measurement is an input liquid level meter, that is, put the liquid level measuring instrument into the medium of the liquid level to be measured, as the liquid level changes, the pressure detection element such as diffused silicon in the pressure transmitter converts the static pressure into a resistance signal for liquid level detection, and the input liquid level meter can be directly put into the measured medium. The characteristics of the input pressure level gauge: (1) Simple structure, solid structure, no moving parts. (2) Easy to install and use, long service life. (3) The measurement range is relatively wide, which can measure from water and oil to phases with large viscosity. (4) It is not affected by foaming, deposition and electrical retention of the measured medium, no material fatigue and wear, and is not sensitive to vibration and impact. (5) Low price and high reliability. (6) When installing, pay attention to select a relatively stable fluid, small fluctuations in the installation of the place, if you can not avoid the water impact, friction and vibration, need to install isolation pipe, reduce the water impact, to ensure the accuracy and stability of the measurement. (7) When installing the input level gauge, it is best to leave the bottom of the pool or tank 100mm to 200mm to reduce the accuracy of the measurement because there is mud and medium sediment at the bottom of the pool or tank. (8) In the environment of poor water quality, especially when the medium has a lot of suspended matter and impurities, it is easy to block the pressure hole, affecting the measurement accuracy. It is necessary to clean the liquid level gauge and dredge the pressure hole regularly to ensure accurate and stable measurement. The pressure type liquid level meter is suitable for the process flow with good water quality, such as the supernatant collection tank, filter tank, clear pool, and external drainage tank. By installing an isolation pipe to avoid the sludge impurities at the bottom of the pool, it can also be used for the concentration tank with stirring. The antenna of the radar sensor transmits electromagnetic wave signals in the form of a beam, and the transmitted waves are reflected on the surface of the material to be measured, and the reflected echo signal is still received by the antenna. Each point of the transmitted and reflected beam is collected by ultrasonic sampling. After the signal is processed by the intelligent processor, the distance between the medium and the probe is obtained, and the terminal display is sent for display, alarm, operation, etc. The distance D from the material surface is proportional to the time travel T of the pulse: D=C×T/2 where C is the speed of light since the distance E of the empty tank is known, the level L is: L= e-d Radar level meter features: (1) Radar level meter adopts integrated design, no moving parts, no mechanical wear, long service life. (2) Due to the characteristics of electromagnetic waves, it is not affected by the environment. Therefore, its measurement has a wide range of applications. The probe of the radar level meter has no contact with the surface of the medium, which is a non-contact measurement, and can accurately and quickly measure different media. The probe is almost unaffected by temperature, pressure, gas, etc. It can be used in harsh working conditions, large changes, and ultrasonic level gauges such as water, steam, and foam can not be used. (3) The radar level gauge is also suitable for use in situations where there is a stirrer, the liquid level is changeable and changeable. (4) The radar level meter is relatively expensive, but it can almost be applied to the level control process of each process of sewage treatment.

The magnetostrictive liquid level meter is a kind of magnetostrictive liquid level displacement sensor. A float is provided outside the sensor measuring rod of the magnetostrictive level meter, which can move up and down along the measuring rod as the liquid level changes.   Magnetostrictive level meter is a kind of high precision liquid level measuring instrument, also known as magnetostrictive level displacement sensor. Its working principle is based on the magnetostrictive effect (also known as the Weidman effect), which uses this physical phenomenon to achieve accurate liquid level measurement. The magnetostrictive level meter consists of three key components: Circuit unit: Responsible for generating a current pulse and detecting the returned torsion wave signal. Float (float) : built-in permanent magnet, with the rise and fall of the measured liquid level and move up and down, forming a static magnetic field. Probe rod (waveguide or rod) : made of a special magnetostrictive material, used to transmit current pulses and torsional wave signals.     Working principle   Initial pulse: The electronic transmitter periodically sends a short pulse of electric current to the probe rod, which creates a magnetic field inside the probe rod that travels rapidly along the rod. Magnetic field interaction: The float moves up and down with the rise and fall of the measured liquid level, and the permanent magnet inside the float forms a static magnetic field around it. When the pulsed magnetic field generated by the transmitter meets the static magnetic field of the float, it causes a magnetostrictive effect at the position where the two interact, resulting in a tiny twist wave (or echo pulse) at that point.   Signal detection: The torsion wave travels back along the probe rod at a fixed ultrasonic speed, and when it reaches one end of the probe rod, the electronic transmitter is able to detect the returned torsion wave signal. Time measurement: By accurately measuring the time difference between the launch of the initial pulse and the reception of the tortuous wave signal, and then based on the speed of the tortuous wave propagation in the material, the actual distance of the float (and the liquid level) relative to the bottom of the sensor can be calculated, so as to determine the height of the liquid level. The advantages of using a magnetostrictive level meter for liquid level measurement are as follows: Strong reliability: Because the magnetostrictive level meter adopts the waveguide principle, there is no mechanical moving part, so there is no friction and no wear. The whole converter is enclosed in stainless steel tube, and the measuring medium is non-contact, the sensor works reliably and has a long life.   High precision: Because the magnetostrictive liquid level meter works with waveguide pulse, the measured displacement is determined by measuring the time of the start pulse and the end pulse, so the measurement accuracy is high, and the resolution is better than 0.01%FS, which is difficult to achieve the accuracy with other sensors. Good safety: Magnetostrictive level meter has high explosion-proof performance, intrinsic safety and explosion-proof, safe to use, especially suitable for the measurement of chemical raw materials and flammable liquids. The magnetostrictive level meter is easy to install and maintain: The magnetostrictive level meter is generally installed through the existing pipe port on the top of the tank, especially for the installation of underground storage tanks and storage tanks that have been put into operation, and can be installed without affecting normal production.   Easy to automate the system: the secondary instrument of the magnetostrictive level meter uses the standard output signal, which is convenient for the microcomputer to process the signal, easy to realize the networking work, and improve the automation of the entire measurement system. Applications: Magnetostrictive level meters are widely used in a variety of industrial level measurements due to their high precision, high stability, high reliability and low sensitivity to environmental changes, including but not limited to: Petrochemical industry: Used for storage tanks, reactors and pipelines and other equipment level monitoring and control, to ensure the stability and safety of the production process.   Environmental protection water treatment industry: monitor the liquid level of sewage treatment tanks, sedimentation tanks and other equipment to ensure the smooth progress of sewage treatment process. Food processing industry: Monitor the liquid level in the liquid mixing tank to ensure that the raw materials are mixed in the correct ratio to ensure the quality of the final product. Other industries: such as pharmaceutical, energy, hydrology, water conservancy, grain processing, brewing and other industries, for various liquid tank level measurement and control   var first_sceen__time = (+new Date()); if ("" == 1 && document.getElementById('js_content')) { document.getElementById('js_content').addEventListener("selectstart",function(e){ e.preventDefault();  }); }

Radar level gauge is a device used to detect the level height of liquid or solid materials. It is based on the characteristics of radar waves to measure, known for its high precision and strong stability, and is widely used in industrial, environmental protection, water and other fields. Below we will elaborate on the working mechanism of the radar level gauge and its application fields.   01 The operating principle of radar level meter mainly depends on the transmission and reception of radar waves   1. Send out radar waves: The transmitter inside the radar level gauge will send out a narrow beam of radar waves, usually microwave or millimeter waves. These radar waves travel through the air at the speed of light and are reflected when they hit the surface of a liquid or solid material. 2. Receive the reflected signal: The receiver of the radar level meter will receive the radar wave reflected back from the surface of the liquid or material. The receiver records the time and strength of the reflected signal. 3. Calculate the liquid level height: By measuring the time interval from transmission to reception, the radar level meter can calculate the distance between the liquid or material surface and the sensor. Combined with the location of the sensor and the known size of the liquid or material container, the height of the liquid level can be accurately calculated.   The advantages of 02 radar level meter are mainly reflected in the following three aspects 1. High precision: the radar wave travels fast and is not affected by the properties of liquids or materials, so the radar level meter has high measurement accuracy. 2. Strong stability: radar level gauge is not affected by environmental temperature, pressure and humidity and other factors, with good stability and reliability. 3. Wide adaptability: Radar level meter is suitable for all kinds of liquid level/level measurement and monitoring. 1. Industrial field: Radar level gauge plays an important role in petrochemical, chemical industry, food processing, pharmaceutical and other industries, and can be used for liquid level detection and control of various liquid or material storage tanks. 2. Environmental protection: The application of radar level meter in the environmental protection industry is also indispensable, such as liquid level monitoring in sewage treatment plants, water treatment equipment, landfills and other places to ensure the smooth progress of environmental protection work. 3. Water affairs: Radar level meter is of great significance in water affairs management, such as water level monitoring and water quantity measurement in reservoirs, rivers, hydrology stations and other places, providing key data guarantee for water resources management. The radar level gauge uses the principle of transmitting and receiving radar waves to accurately measure liquid or material level. Because of its high precision and strong stability, it is widely used in industrial, environmental protection, water and energy fields, providing key technical support for production and management of related industries.

The antenna of the radar sensor transmits the electromagnetic wave signal in the form of a beam. The transmitted wave reflects on the surface of the measured material, and the reflected echo signal is still received by the antenna. Each point of the transmitted and reflected beam is collected by ultrasonic sampling. After the signal is processed by the intelligent processor, the distance between the medium and the probe is obtained, and the terminal display is sent for display, alarm, operation, etc. Features: The biggest feature of the radar level meter is that it has significant effect under harsh conditions. Whether it is toxic media, or corrosive media, whether it is solid, liquid or dusty, slurry media, it can be measured. In terms of measurement, it has the following characteristics: 1, continuous and accurate measurement The probe of the radar level meter has no contact with the surface of the medium, which is a non-contact measurement, and can accurately and quickly measure different media. The probe is almost unaffected by temperature, pressure, gas, etc. (only 0.018% at 500 ° C and 0.8% at 50bar). 2. It has suppression function for interference echo 3, accurate and safe energy saving The chemical and mechanical properties of the material used in the radar level meter are quite stable, and the material can be recycled, which has great environmental protection effect. 4, no maintenance and strong reliability Microwaves are almost free from interference and are not in direct contact with the measuring medium, and can almost be applied to a variety of occasions, such as vacuum measurement, liquid level measurement or material level measurement. Due to the use of advanced materials, it is very durable for extremely complex chemical and physical conditions, and it can provide accurate and reliable, long-term stable analog or digital level signals. 5, easy maintenance, simple operation Radar level meter has fault alarm and self-diagnosis function. Analyze the fault according to the error code prompted by the operation display module, determine the fault and eliminate it in time, make the maintenance and correction more convenient and accurate, and ensure the normal operation of the instrument. 6, wide range of application, can measure almost all media From the shape of tank body, the radar level meter can measure the liquid level of spherical tank, horizontal tank, cylindrical tank, cylindrical cone tank, etc. From the function of tank, the liquid level in storage tank, buffer tank, microwave tube and bypass tube can be measured. From the measured medium, liquid, particle, slurry, etc., can be measured. Summary: In general, the radar level meter has a wide range of use and is a non-contact measurement method. Excellent material, low failure rate. Guided wave radar level gauge Principle: Guided wave radar level meter is a measuring instrument based on the principle of time travel. Radar waves run at the speed of light, and the running time can be converted into level signals through electronic components. The probe emits a high-frequency pulse that travels along the cable probe, and when the pulse hits the surface of the material, it is reflected back to be received by the receiver inside the meter, and the distance signal is converted into a level signal. peculiarity 1, the steam and foam have a strong inhibition ability, the measurement is not affected; 2, not affected by the density of liquid, the degree of porosity of solid materials, temperature, dust during feeding; 3, low maintenance, high performance, high precision, high reliability, long service life. Is there a difference? The contact mode is different: the radar level meter is non-contact, and the waveguide level meter is contact. That is to say, in the case of higher food grade requirements, pilot type can not be used. Different working conditions of the medium: guided wave radar type level meter needs to consider the corrosion and adhesion of the medium, and too long guided wave radar installation and maintenance is more difficult. Under the condition of low dielectric constant, the measurement principle of both radar and guided wave radar is based on the difference in dielectric constant. Since the emitted waves of ordinary radar are diverging, when the dielectric constant is too low, the signal is too weak and the measurement is unstable, while guided wave radar waves propagate along the guide pole and the signal is relatively stable. In addition, general guided wave radar also has the function of bottom detection. It can be modified according to the measured value of the bottom echo signal, so that the signal is more stable and accurate. The selection is different: ordinary radar can be used interchangeably, and guided wave radar can not be used interchangeably because the length of the guide rod (cable) is fixed according to the original working condition, and the selection of guided wave radar is more troublesome than ordinary radar. The measurement range is different: ordinary radar is more common in the application of 30, 40m tanks, and even 60m can be measured. Guided wave radar should also consider the stress of the wave guide rod (cable), which is also due to the reason of stress, the measurement distance of guided wave radar is generally not very long. However, guided wave radar has obvious advantages in some special working conditions, such as stirring in the tank and large medium fluctuation, the measured value of guided wave radar with fixed bottom in such working conditions is more stable than that of flexible radar; There is also the level measurement in the small tank, due to the small installation measurement space (or more interference in the tank), the ordinary radar is generally not applicable, then the advantages of guided wave radar appear.

Level measuring instrument In the production process, the surface position of the liquid stored in the container is called the liquid level; The surface position of the solid pile at a certain height is called the material level; The position at which two incompatible substances with different densities meet is called the boundary or interface. Liquid, material level and interface are collectively called level. The instrument for level detection is called the level detection instrument. At present, the liquid level instruments are mainly used in Qingshen Gas field, which mainly include float level controller, magnetic flap level meter and radar level meter. 4.1 Float level controller The float liquid level controller is suitable for liquid level control in various containers. When the liquid level reaches the switching value of up and down, the controller contact sends an on-off switch signal. At present, the instrument used in Qingshen gas field is mainly installed on each separator, and is used with flash alarm to make hard alarm on the upper and lower levels of liquid level set in the container. 4.1.1 Main structure It is composed of two parts, the float ball assembly and the contact assembly, which are isolated from each other. 4.1.2 Working Principles The change of the liquid level is felt by the external float ball, and the instrument contact is driven by the magnetic shaft to realize the alarm and control of the liquid level. When the measured liquid level rises or falls, the float ball rises and falls, so that the magnetic steel at its end swings up and down, and the magnetic steel installed in the same magnetic pole in the shell swings up and down through the magnetic repulsion, and the contact at the other end makes the static contact connected or disconnected, and controls the flashing signal alarm to issue an audible and visual alarm, or other control functions. When the float level controller is rising and falling with the liquid level, only when it is in the upper and lower two largest positions of the operating range, the moving contact will make the static contact connected or disconnected, sending a on-off signal, and in the process of the lifting action, the static contact is always in the disconnected state, so as to prevent false alarm and continuous alarm. 4.1.3 Troubleshooting Float level controller plays a switch role in the production process, usually used in conjunction with the flashing signal alarm or other chain equipment, so the fault is to lose the switch function, according to the actual maintenance experience, the fault mainly has the following aspects: (1) Float card neck, for the high alarm float level controller, float card neck is mostly due to the oil and impurities floating on the surface of the liquid level, and this situation occurs in winter, when the liquid level in the container drops, a small part of the oil and impurities above the float card neck due to cold weather, resulting in the float can not work normally. For the low level alarm, it is mostly due to too much sludge in the container. The phenomenon caused by these two cases may make the flashing signal alarm light in the duty room steady on or reach the alarm limit. In the first case, the liquid level in the container can be raised beyond the float, and the oil and impurities can be equalized with the liquid temperature in the container. In the second case, you can only clean the tank and remove the sludge in the container. (2) Float turn, due to long-term use, float level controller float connection is corroded, resulting in float turn. (3) Magnetic steel demagnetization, due to long-term application, the float level controller float end of the magnetic steel loses magnetism, and when it moves up and down, there is no magnetic repulsion installed in the shell of the same magnetic pole of the magnetic steel swings up and down, the other end of the contact is connected or disconnected with the static contact, it can not play the role of contact switch. In this case, the container can only be stopped and a new float level controller can be replaced. Figure 4-1 Object and working principle of the float liquid level controller 4.1.4 Precautions (1) The diameter of the opening of the installation container should be greater than the diameter of the float, and the action range of the float should reach the two largest positions of the upper and lower, otherwise it cannot be installed or the float cannot work normally. (2) Can not be installed near the inlet and outlet, otherwise the liquid level fluctuation is large, easy to cause false alarm. 4.2 Magnetic flap level gauge The magnetic flap liquid level meter can be used for the medium liquid level detection of various equipment such as towers, tanks, tanks, ball containers and boilers. This series of level gauges can achieve high sealing, leak proof and suitable for high temperature, high pressure, corrosion resistance. It makes up for the defects such as poor clarity and easy rupture of the glass plate (tube) liquid level gauge, and there is no blind area in the whole process measurement, with clear display and large measurement range. At present, the instrument used in Qingshen Gas field is mainly installed on the separator and the sewage tank, which is used to continuously monitor the change of the liquid level in each container. The liquid level meter of the separator is used with the automatic drainage system to realize the automatic discharge of sewage. 4.2.1 Working Principle The magnetic flip plate liquid level meter is a new type of instrument which indicates the liquid level by turning the two-color magnetic flip plate driven by the magnetic steel in the float. The magnetic float in the cavity floats up and down with the liquid surface, and in the floating process, the magnetic coupling drives the magnetic flap to turn over and make it red, so as to intuitively indicate the liquid level value and keep it at the same height as the liquid level in the container. At the same time, through magnetic coupling, a certain magnetic sensor on the corresponding liquid surface is activated and converted into the corresponding (4-20) mA current output by the converter. Figure 4-2 Physical object and working principle of the magnetic rotating column liquid level gauge 4.2.2 Troubleshooting Table 4-1 Common faults of a magnetic flap liquid level gauge Fault Cause Troubleshooting The liquid level rises or falls or the instrument has no indication. The float is damaged. Replace the float. The float loses magnetism. The float is stuck or cannot be lifted or lifted Clean the liquid level gauge chamber and float flip plate lose magnetism. The magnetic flip plate does not work. The magnetic flip plate indicates an abnormal magnetic flip plate 4.2.3 Precautions (1) The installation of the liquid level gauge must be vertical to ensure that the float assembly moves freely up and down the main tube. (2) No magnetic permeator is allowed around the body of the liquid level gauge, otherwise it will directly affect the normal operation of the liquid level gauge. (3) The laying of the electric tropical zone can not be close to the magnetic flap to prevent the magnetic flap from deformation due to heat. 4.3 Radar level gauge The instrument used in Qingshen Gas field is mainly installed on the separator, methanol tank and sewage tank, which is used to continuously monitor the change of liquid level in the container. 4.3.1 Structure Radar level meter is mainly composed of radar detector and radar display instrument. The radar detector mainly consists of three parts: main body, connecting flange and antenna. 4.3.2 Working Principle Transmitting - reflecting - receiving is the basic working principle of radar level meter. A high-frequency oscillator is used as a microwave generator, and the microwave generated by the generator is directed to the radiation antenna by a waveguide, and is shot down. When the microwave encounters the obstacle liquid level, some of it is absorbed and some of it is reflected back. By measuring the transmitted wave and reflected wave liquid level to achieve some parameters of the relationship between liquid level measurement. Figure 4-3 Radar liquid level gauge and working principle 4.3.3 Troubleshooting Table 4-2 Common faults of radar liquid level gauge Fault Cause Troubleshooting Common Display Full tank antenna condensation Strengthen antenna heat preservation Incorrect display Parameter Settings Reset the machine itself Troubleshooting 4.3.4 Precautions (1) Antenna insulation should be strengthened to avoid antenna condensation. (2) The height of the liquid level is obtained through calculation, therefore, the parameters entered by the computer must be correct.

Radar level meter is a universal radar level meter, which is based on the principle of time travel. Radar waves run at the speed of light, and the running time can be converted into level signals through electronic components. The probe emits a high-frequency pulse that travels at the speed of light in space, and when the pulse hits the surface of the material, it is reflected back to be received by the receiver inside the meter, and the distance signal is converted into a level signal. The radar level meter transmits very short microwave pulses of very low energy through the antenna system and receives them. Radar waves travel at the speed of light. The running time can be converted into a level signal by electronic components. A special time-extension method ensures stable and accurate measurements in a very short time. Even in the case of complex working conditions, there are false echoes, with the latest micro-processing technology and debugging software can accurately analyze the level of the echo. The antenna receives the reflected microwave pulse and transmits it to the electronic circuit. The microprocessor processes the signal and recognizes the echo generated by the micropulse on the surface of the material. The correct echo signal recognition is done by intelligent software, and the accuracy can reach the millimeter level. The distance D from the material surface is proportional to the time travel T of the pulse :D=C×T/2 where C is the speed of light because the distance E of the empty tank is known, then the level L is :L= e-d Output by input empty tank height E(= zero), full tank height F(= full scale) and some application parameters to set, application parameters will automatically make the instrument adapt to the measurement environment. Corresponds to 4-20mA output. Application medium: The intelligent radar level meter is suitable for non-contact continuous measurement of the level of liquid, slurry and granular material, suitable for large changes in temperature and pressure; Where inert gases and volatilization are present. The measuring method of microwave pulse is adopted, and it can work normally in the range of industrial frequency band. Beam energy is low, can be installed in a variety of metal, non-metal containers or pipelines, no harm to the human body and the environment.

Radar level meter can be used for continuous measurement of different material levels, suitable for high temperature, steam, high dust and volatile gas and other harsh environment, widely used in energy, metallurgy, petrochemical, building materials and other industries. The main technical indicators of radar level meter meet or better than similar products at home and abroad, the installation and debugging is simple, can be used single, can also be used network.       In addition to the performance described above, the radar level meter also has signal processing advantages, which and related factors are described below. 1. After the installation and operation of the radar level meter, the space surface situation of the application is constantly changing. Taking the reaction tank as an example, the chemical process needs to measure a variety of media, the liquid level will change when feeding, such as material adhesion, the physical or chemical characteristics of the inner surface of the tank, etc., these changes will inevitably affect the strength of the reflected signal.       2. The liquid level measured by the radar level meter also has a variety of changes, and the multiple reflections of the signal will change under different circumstances. If at rest is a mirror; The surface will fluctuate when the liquid level changes; Sometimes there may be bubbles. 3, when the radar level meter measures the height of the liquid surface is different, its measurement space shape is constantly changing, and the reflection and oscillation of the signal are also different. Especially when the measured space has a curved surface, such as a spherical container, a vaulted tank or a horizontal elliptical tank, because the surface has a focusing effect on electromagnetic waves, the height change of the liquid level has a greater impact on the reflection.       4, the medium in some application sites will also directly affect the radar wave transmission and reception of the radar level meter, on the one hand, it is reflected in the effect on the antenna: such as steam condensation on the surface of the antenna, the material crystallization on the surface of the antenna. On the other hand, the volatilization or atomization of the medium in the tank will also affect the propagation of the radar wave, and then affect the measurement. 5, the application of radar level meter is often limited to a small space, rather than a huge open space. The signal emitted by the radar level meter is electromagnetic wave, which is divergent in space and has all the characteristics of electromagnetic wave, such as reflection, diffraction, refraction and so on. Any object in the propagating space will produce a reflection of the signal. A small space will produce many reflected signals, including the direct reflection of the surface of the object, and the back and forth reflection and oscillation of the signal (multiple reflections between surfaces).

Radar is a transliteration of English radar, from the abbreviation of radio detection and ranging, meaning "radio detection and ranging", that is, to find targets by radio methods and determine their spatial position, so radar is also known as "radio positioning". Whenever talking about the origin of radar, there are always different opinions, but it is undeniable that radar technology first rose in the military field, and more mature military radar technology has appeared during World War II. The principle of radar is to measure the orientation of the target by using the sharp azimuth beam of the antenna, by measuring the elevation Angle against the narrow elevation Angle beam, so that the height of the target can be calculated according to the elevation Angle and distance. The principle of distance measurement is to measure the time difference between the transmitted pulse and the echo pulse, because the electromagnetic wave travels at the speed of light, it can be converted into the accurate distance between the radar and the target. The principle of speed measurement is the frequency Doppler effect generated by the radar according to the relative motion between itself and the target. The frequency of target echo received by radar is different from the frequency of radar transmission, and the difference between the two is called the Doppler frequency. One of the main pieces of information that can be extracted from the Doppler frequency is the rate of distance change between the radar and the target. When the target and the clutter exist in the same spatial resolution unit of the radar, the radar can detect and track the target from the clutter by using the difference of Doppler frequency between them. 1. According to the form of radar signal classification, there are pulse radar, continuous wave radar, pulse compression radar and frequency agility radar. 2. According to the Angle tracking method, there are monopulse radar, conical scanning radar and covert conical scanning radar. 3. According to the classification of the parameters of the target measurement, there are altimeter radar, two-coordinate radar, three-coordinate radar, friend and foe radar, multi-station radar, etc. 4. According to the technology and signal processing method of radar, there are coherent accumulation and non-coherent accumulation, moving target display, moving target detection, pulse Doppler radar, synthetic aperture radar, scanning and tracking radar. 5. According to the antenna scanning method, it is divided into mechanical scanning radar, phased array radar, etc. 6. According to the radar frequency band, it can be divided into over-the-horizon radar, microwave radar, millimeter-wave radar and Lidar. With the scientific progress in various fields such as microelectronics, radar technology continues to develop, and the research content and application fields are constantly expanding. At present, it has been widely used in military, aviation, communications, meteorology, transportation, environmental monitoring and other fields and industries. The water conservancy industry has also widely applied radar to water body monitoring, and derived a series of monitoring equipment, such as radar level meter, radar current meter, radar electronic water gauge and so on.         02 Measuring line radar Water level meter # Introduction Measuring line radar water level meter is an intelligent non-contact liquid level (level) measuring instrument based on the principle of microwave radar reflection. Using the transmitting, reflecting and receiving mode, the propagation speed of microwave is known to be a constant. By measuring the time difference between the transmitting pulse and the echo pulse, the distance between the radar antenna and the liquid surface can be calculated, and the liquid level height can be converted. The advanced detection technology and calculation algorithm are adopted to improve the measuring accuracy of the instrument, inhibit the interference echo, and ensure the real and effective measurement results. Radar water level meter can be widely used in various liquid level and solid material level height measurement, can also be used for distance measurement. It is very suitable for liquid level measurement in rivers, open channels, lakes, reservoirs and other scenes. Application Case 1 Application Case 2 Application Case 3...... 03 Characteristics of radar water level gauge           # Strong anti-interference ability is not affected by environmental factors such as temperature, sediment, dust, river pollutants, floating objects on the water surface, and air pressure. # Non-contact measurement adopts non-contact mode, the sensor and the water body are not in contact, and are not affected by the hydrological environment, which greatly reduces the workload of operation and maintenance. # Range Large range can be customized, up to 40 meters. # Low power consumption Low power microprocessor design, ultra-low power sleep mode, fast wake up. The device can be battery powered or solar powered.

In the measurement field of all walks of life, the radar level meter will be used, because of its unique advantages, but also because its accuracy is very good, but if the accuracy is affected, the effect of the product will be greatly reduced, so we need to pay more attention to welding. In order not to affect the accuracy of radar level meter measurement, we should first consider the corrosion and adhesion of the measured medium on the product, which needs to ensure that the final value of the measurement range is at least 100mm from the antenna tip. In addition, you need to pay attention to the following three aspects: 1. In the principle of overspill protection, a safe distance can be defined to attach to the blind area. 2. The minimum value of the measuring range of the radar level meter has a certain relationship with the antenna. 3. Foam can both absorb and reflect microwaves, and can be measured under certain conditions with different concentrations. In addition, since the radar sensor can be measured through the waveguide tube or by-pass tube, the inner wall of the measuring tube must be smooth. The internal diameter of the measuring tube should be consistent with the diameter of the horn as far as possible, and if the length is not enough, the measuring tube can also be extended by a pre-welded flange or welded head. At the same time, it should be very noted that when welding, no concave and convex points can be produced, and the welding can not penetrate the tube wall, otherwise it will produce a strong false echo, so that the accuracy of the radar level meter measurement is affected.

The cause of this failure is mostly water beads or dirt under the radar level gauge transmitting antenna or isolation window. Remove the level gauge, use a clean, soft cotton cloth to dry the antenna or under the isolation window of water or dirt, restart can generally return to normal. To scrub the transmitter antenna of the level meter, scrub it with a soft cotton cloth dipped in alcohol, gasoline and other solvents, and do not scrub with alkaline solvents. The causes and treatment methods of transmitting antenna fouling are as follows. ① The water droplets formed after the steam cooling in the container are attached to the transmitting antenna, hindering the emission of microwaves. Isolation devices can be used, and some factories use Teflon isolation devices, and have achieved better results. The material not only does not hinder the emission of microwave, but also plays an isolating role. After the isolation device is installed in a certain way, the steam in the container can be isolated from the transmitting antenna, and the condensate water attached to the isolation device can be distributed in a certain form after formation, so as not to affect the purpose of microwave emission. ② When the equipment uses the mixing motor, the slurry is thrown, so that the installation sleeve and the transmitting antenna are dirty and scaled. As long as the stirring motor turns, it will raise the slurry, which is unavoidable. The scaling problem can be solved by increasing the diameter of the casing. The scaling degree of the day diameter casing will affect the emission wave in a much longer time than that of the small diameter casing. When the scale of large diameter casing reaches a certain degree, part of the scale will fall off under the action of gravity. (3) Non-standard installation of the level gauge will also cause the fault, the antenna does not extend the sleeve, the diameter of the sleeve is too small, the pipe wall is rough and there are welds, etc., which may cause more interference echoes. Usually, the upper blind area can be increased, and the parameters can be set by the full tank processing function of the instrument. If it does not work, consider repositioning the installation. ④ When the scale or dirt on the antenna is small, the echo intensity will be weakened, and only occasionally jump to the maximum. Usually take power off restart; Or use the echo re-search function, from the multiple echo list measured by the instrument, select the echo that is close to the actual liquid level as the surface echo, it is possible to restore the instrument to normal. When scale or dirt accumulation on the antenna is serious, the intensity of the echo may be lower than the threshold value. It is better to set the threshold value to 20% of the surface echo under stable conditions. If it cannot be restored by software treatment, only remove it and clean the dirt or dirt on the antenna. Antenna fouling or dirt is a common problem, regular cleaning of antenna fouling and dirt, will greatly reduce this kind of failure. The liquid level is normal, and the display fluctuation can be solved by modifying the time constant and increasing the damping time of the instrument. There is condensation or water beads on the antenna, the mixer makes the surface of the measured liquid level fluctuate sharply, and the liquid level gauge is installed above the discharge port, which will enhance the interference echo in the container and cause the liquid level display value to fluctuate. There are condensation water beads on the antenna, you can take the power off and restart the method to try, if there is no change, you can only remove the transmitter head, wipe the condensate on the antenna, or search for the echo again. When the display fluctuation is considered the most is poor line contact, electromagnetic interference, electronic circuit problems; However, do not ignore the impact of the display instrument or DCS card, such as some DCS card with insufficient load capacity, there will be normal process liquid level, but the instrument display value frequently fluctuate. Sometimes the card may be restored to normal, otherwise the channel or card should be replaced. When the container will be emptied or will be full, the instrument will still output a signal that is obviously inconsistent with the liquid level change, for example, when the liquid level in the container will be full, it will still show a low liquid level value. The causes of the fault are as follows. ① Antennas or antennas near the attachment, will produce interference echoes. Too much dirt accumulated on the antenna will strongly reflect the microwaves, causing the meter to display a fixed high level. By cleaning the antenna and the dirt and attachments near the antenna, and wiping the transmitting antenna, most faults can be eliminated. There are obstacles or fixed objects in the tank, resulting in a strong reflection of the microwave, and the value of the echo intensity is larger at this time. Most of the failures occur in the empty tank state, the first trial software processing, the purpose is to suppress interference echoes, shield false signals. To register the interference echo, the echo measured at present is registered in the echo list as a false echo, after registration, obstacles or fixed objects in the tank will cause interference echo; Or use the "near field suppression" function to eliminate the fault, by setting the near field suppression distance, so that the instrument will register the echo in this range as not to measure the disturbed echo. The effect is better when there is a hanging material near the weld, antenna or antenna of the mounting flange. The most effective measure is to re-select the installation location of the instrument, or contact the technician to rectify the obstacles or fixed objects in the tank to eliminate the occurrence of failure. When the liquid level is displayed as a fixed deviation, first check whether the tank height is set correctly, so that the zero point of the instrument is consistent with the reference zero point of the process. It should also be checked whether the scale level is the same as the measuring range of the upper computer, and when the measuring range of the display instrument is not known, such as VFO3 level meter can be solved by dynamic setting (F11) test function, so that the transmitter output 4mA and 20mA query respectively. First verify the height of the tank, and then check that the basic parameters are set in accordance with the height of the tank. Power off and restart to try whether it can return to normal. If it does not return to normal, only remove the transmitting head to check whether there is condensation water on the antenna. If there is condensation water or dirt, clean and wipe it, and then install it to observe whether it is normal. When the liquid level displays the minimum empty tank, the display value is not zero, such as the 5600 instrument will display the "Invalid" wave loss alarm, mostly the radar surface echo signal is lost when the tank is empty. Display panel can be used to re-search the echo; Or use the empty tank handling function of the instrument to deal with the loss of surface echo near the bottom of the tank. If the surface echo is lost, this function will cause the transmitter to display zero liquid level. The actual range of the instrument is too small, the echo signal is lost when the tank is empty, and the range should be re-verified, or a larger antenna should be selected. Sometimes the process level is about to fill the tank, but the instrument shows a very low level, which is due to the increase of multiple echoes in the tank when the level rises, and the instrument recognizes a beam of echoes with a larger time travel as the measurement echo, resulting in incorrect calculation results. The field suppression distance should be modified and the false signal should be presented to eliminate the influence of multiple echoes.

At present, radar water level meter can be used in different working conditions such as river, channel, culvert and so on to measure water level change, although the water is not corrosive, compared to the oil industry, chemical industry and other complex industries, the working condition is relatively simple, but also need to pay attention to many problems, only to do the details, can ensure that the radar water level meter measurement accurate, effectively extend the service life, Save business costs. Today, we share some tips for installing and using radar water level meters to help you better use radar water level meters.   Measurement Principles & Advantages Radar water level gauge Radar water level gauge is an electronic device that uses electromagnetic waves to detect targets. Its main function is used for water conservancy monitoring, sewage treatment and flood prevention early warning. Its main measurement principle is to emit radar pulses from the radar water level sensing antenna, the antenna receives the pulse reflected back from the water surface, and records the time T, because the propagation speed of electromagnetic wave C is a constant, thus obtaining the distance to the water surface D. The technology of radar water level gauge is mature, with the advantages of measuring accuracy, stability, flexibility, high reliability, low power consumption, easy installation, convenient parameter setting, simple maintenance, and not limited by environment and geographical location. Sticky note " 1, before installation, be sure to do a good job of inspection, mainly check the sealing head and cable of the radar water level gauge, to ensure that the sealing head and cable are not damaged. 2, in the installation, the cable head must be tightened, before entering the electrical interface, the cable must be bent downward to ensure that the shell does not flow into the water, unused electrical interface must be plugged tightly. 3, installation, need to install a rain cover, summer rainy and direct sunlight, in order to extend the service life of the radar water level meter, it is recommended to install a rain cover to reduce the impact of direct sunlight and rain on the radar water level meter. 4, ensure that the cable meets the electrical connection specifications, cable connection details related to the normal use of radar water level gauge and social life and property safety, must be strictly in accordance with the relevant requirements. 5, pay attention to the horizontal rod when installing, it is recommended to make the horizontal rod can be rotated or telescopic horizontal rod, convenient for later adjustment and maintenance. 6, it is worth mentioning that when measuring the channel, the radar water level meter should be installed in the middle of the channel. The channel is generally narrow and installed in the middle, which can minimize the impact of the channel wall on the radar water level gauge. 7, finally, pay attention to observe the radar water level gauge, do a good job of daily maintenance, problems should be timely feedback.