Sheathed thermocouple have the advantages of bending, high pressure resistance, fast thermal response time and durability.
Sheathed thermocouple can directly measure the temperature of liquid, steam and gaseous media and solid surfaces in the range of 0℃～1200℃ in various production processes.
Sheathed thermocouples are usually used along with display instruments, recording instruments, electronic computers and so on. It is able to directly measure the temperature of liquid, steam and gas and solid surface in a variety of production processes within the range of 0 ~1300℃.
Sino-Inst offers a variety of Sheathed Thermocouple . If you have any questions, please contact our sales engineers.
There are actually many techniques for using sheathed thermocouples.
It has bendable performance. The thermal resistance of the sheath can be bent in any direction . except for the head, so it is suitable for the temperature of the complicated structure and small equipment.
The sheathed thermocouple has good vibration and impact resistance. Therefore, its life is longer than ordinary thermal resistance.
The sheathed thermocouple has a long service life. Because the resistance body of the sheathed thermal resistance is maintained by the metal sleeve, the thermal resistance wire is not easily corroded by harmful media.
It is suitable for measuring in strong alkali and corrosive medium. with a temperature resistance of 250℃, and the fixed installation situation can also use the same PTFE fixed thread.
According to the measurement temperature range and side measurement object, select the appropriate thermal resistance model, specification and maintenance tube information.
What Is Sheathed Thermocouple?
Sheathed thermocouples consist of an outer metallic sheath, which contains the insulated internal leads, embedded within a high-density ceramic compound (mineral-insulated cable, also called MI cable). Sheathed thermocouples are bendable and may be bent to a minimum radius of five times the sheath diameter.
Sheathed thermocouples have different types. Type J, K, T, & E are “Base Metal” thermocouples, the most common types of thermocouples. Type R, S, and B are “Noble Metal” thermocouples, which are used in high temperature applications (see thermocouple temperature ranges for details)
In terms of the sheath thermocouple, the environment temperature is 20 + 15℃, the relative humidity is not more than 80%, the test voltage is 500 + 50V(DC), the insulation resistance between electrode and outer sleeve≥1000MΩ.m.
That is to say, the insulation resistance for sample of 1m is 1000MΩ;
the insulation resistance for sample of 10m is 100MΩ.
Sheathed Thermocouple’s Working Principle
The electrode of sheath thermocouple are consisted by two different materials of conductor. When there is a temperature difference between the measuring end and the reference end, it will generate the thermal electric potential. The working instrument will show the corresponding temperature value of the thermal electric potential.
How Do You Identify A Sheathed Thermocouple?
If the flame ignites and goes out when you release the gas control knob after holding it in for the recommended 20 to 30 seconds, that’s the sign of a thermocouple malfunction. Before jumping to the conclusion that the thermocouple is at fault, look at the pilot flame.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
The external ultrasonic tank level sensors is the first choice for measuring liquid level and material level on various industrial tanks.
The intelligent ultrasonic tank level sensor installs the ultrasonic probe directly under the tank when measuring. No need to open holes, easy to install. Does not affect on-site production. It can measure various toxic substances and pure liquids in high temperature and high pressure airtight containers. The instrument adopts explosion-proof design to meet explosion-proof requirements. The Internet of Things can be realized through GPRS and Wifi.
Sino-Inst offers a variety of ultrasonic level meters for tank level measurement. If you have any questions, please contact our sales engineers.
The probe is external, no need to open a hole to the container under test.. Really realize non-contact measurement.
It is suitable for accurate measurement of the liquid level of toxic, volatile, flammable, explosive, and highly corrosive liquid media in various closed containers.
The instrument has no mechanical moving parts and has a long life. No corrosion, no pollution, wide use area.
The instrument has built-in ASIC (Intelligent Ultrasonic Special Hardware Integrated Circuit), which makes the instrument small in size, stable and reliable in measurement results. It can be suitable for all kinds of liquids and containers to be tested, and it is easy to install on site without complicated on-site calibration.
The instrument has built-in various calibration functions such as automatic temperature correction and automatic fixed distance calibration. The measurement results are more accurate and reliable.
The instrument has complete functions, with RS485 output, 4-20mA output, and switch output.
Multiple power supply methods available
Backup and restore configuration parameters
The analog output can be adjusted arbitrarily
With digital filtering and echo recognition functions
Fixed interference filtering function can be manually set
Support Bluetooth, GPRS communication, GPS satellite positioning, etc. (Order to buy)
Support custom serial data format
Support custom main display interface
Support MiniSD card data collection (order option)
the liquid cannot be filled with dense bubbles. A large amount of solids, such as crystals, cannot be suspended in the liquid.The bottom of the container cannot deposit a large amount of sand and sediment.
Medium Viscosity
When the dynamic viscosity is less than 10mPaS, it is measured normally. When 10mPaS<dynamic viscosity<30mPaS, the range of the instrument may be reduced. It cannot be measured when the dynamic viscosity is >30mPaS.
note: As the temperature increases, the viscosity decreases, and most high-viscosity liquids are more affected by temperature. Therefore, pay attention to the effect of liquid temperature when measuring viscous liquids.
Container Under Test
Material: The container wall where the measuring probe is installed is required to be made of hard materials that can transmit signals well. Examples: carbon steel, stainless steel, various hard metals, glass steel, hard plastics, ceramics, glass, hard rubber and other materials or their composite materials. If the container wall where the measuring probe is installed is of multilayer material, the layers should be in close contact with no bubbles or gas interlayers. The inner and outer surfaces of the container wall should be flat. Examples: vulcanized hard rubber lining, stainless steel lining, titanium lining Floor.
Wall thickness: 1-100mm
Tank type: spherical tank, horizontal tank, vertical tank, etc.
Probe Installation Requirements:
For iron containers, you can apply silicone grease to the working end of the probe and stick it directly to the bottom of the container with a magnetic suction cup; if the container shell is made of glass or other materials, you can use glue to fix the probe or use a bracket to fix it. The bottom of the container. The probe point must be on the same straight line as the measured distance.
There are no obstructions such as coils directly above the probe;
Keep away from the liquid inlet at the bottom of the tank to avoid the influence of the violent flow of the liquid on the measurement;
Keep away from the position below the liquid inlet on the top of the tank to avoid the impact of the liquid inlet and the violent fluctuation of the liquid level to affect the measurement;
It is higher than the liquid outlet or the sewage outlet to avoid the influence of long-term deposits on the bottom of the tank on the measurement. If the conditions are not met, measures should be taken to ensure that the bottom of the tank is regularly removed;
When the liquid level measuring head is installed by magnetic or welding/adhesive fixing method, the installation surface size on the container wall should not be less than the round surface of Ф80, the surface roughness should reach 1.6, and the inclination should be less than 3°(bypass pipe exce
Ultrasonic level meter is a high-tech product that integrates ultrasound, electronics and software. The various indicators of the ultrasonic level meter have reached the advanced level of similar products in the world. and it is the first-choice instrument for measuring liquid level and material level on various industrial sites.
How Do External Ultrasonic Tank Level Sensors Work?
Install the ultrasonic probe directly below the outer wall of the container under test. No need to open holes, easy to install, and does not affect on-site production. It can accurately measure various toxic substances and various pure liquids in high temperature and high pressure airtight containers.The instrument has built-in ASIC (Intelligent Ultrasonic Special Hardware Integrated Circuit), which makes the instrument small in size, stable and reliable in measurement results, and can be suitable for various liquids and containers to be tested. It is easy to install on site and does not require complex on-site calibration.
The instrument has built-in various calibration functions such as automatic temperature correction and automatic fixed distance calibration to make the measurement results more accurate and reliable. The Internet of Things can be realized through GPRS and Wifi.
How Do You Mount An External Ultrasonic Tank Level Sensor?
The probe is installed externally, no need to open a hole in the container to be tested, and truly realize non-contact measurement.It is suitable for accurate measurement of the liquid level of toxic, volatile, flammable, explosive, strong pressure, strong corrosive and other liquid media in various closed containers.The instrument has no mechanical moving parts and has a long life. No corrosion, no pollution, wide use area.
What Are The Benefits?
Safe : No valves, connecting pipes, joints, no leaks, no contact with the liquid and gas in the tank, very safe, when measuring toxic, corrosive, pressure, flammable, volatile, and easy to leak liquids
Hygiene: liquid level detection and monitoring projects in brewing, beverages, milk production, storage tanks, pipelines, etc. do not come in contact with liquids and cause pollution.
Convenient installation and maintenance: no fire or tank cleaning during installation and maintenance will not affect production.
When measuring the External Ultrasonic Tank Level Sensor, install the ultrasonic probe directly under the outer wall (bottom) of the container under test. No need to open holes, easy to install, and does not affect on-site production. It can be used to treat various toxic substances in high temperature and high pressure airtight containers. Accurate measurement of a pure liquid.
The External Ultrasonic Tank Level Sensor adopts explosion-proof design to meet explosion-proof requirements. The probe is installed externally, no need to open a hole in the container to be tested, real non-contact measurement, suitable for accurate liquid level of toxic, volatile, flammable, explosive, strong pressure, strong corrosive and other liquid media in various closed containers measuring.
The External Ultrasonic Tank Level Sensor has no mechanical moving parts and has a long life. No corrosion, no pollution, wide use area. More about Top 5 Ultrasonic Level Sensor Applications.
In the design work, a reasonable and optimized External Ultrasonic Tank Level Sensor selection scheme was made according to each project. Judging from the production and application, the effect is very good.
1.Field application of butadiene
In a rubber project, it is necessary to measure the level of butadiene in the spherical tank. Butadiene is prone to self-polymerization to produce high molecular polymers, and the selection of ordinary liquid level meters is limited. According to the requirements of “Tank Area Automation System Design Regulations”, “Each pressure storage tank should be equipped with two sets of independent and different types of liquid level measuring instruments”. If the conventional contact liquid level gauge is selected for this project, butadiene is at the dead corner of the detection port The possibility of self-aggregation is very large, so the non-contact type should be given priority to the selection of the level gauge. Finally, a set of non-contact radar level gauges were installed on the top of the tank, and a set of External Ultrasonic Tank Level Sensors were installed on the bottom of the tank. After the field application, the externally attached ultrasonic level gauge measures accurately and the effect is very good.
2.Field application of liquid ammonia
In the design of a certain liquid ammonia spherical tank, the External Ultrasonic Tank Level Sensor also has a good application. The liquid ammonia in the storage tank is a colorless, pungent odor and toxic liquid, which is corrosive to a certain extent. Because the density of liquid ammonia is greatly affected by temperature, the differential pressure level gauge is not applicable in this project, and the external ultrasonic level gauge is finally used for detection.
3.Field application of high pressure storage tank
In a high-pressure hydrogenation plant, due to the unstable parameters of the original level gauge on the high-pressure storage tank, the owner wanted to add a level gauge to compare with it. However, the installation space of the high-pressure vessel was small on site, and the conditions for reopening were not available. After negotiation, it was decided to adopt an external ultrasonic level gauge, which not only avoided the economic loss caused by the shutdown of the device, but also prevented new pressure vessels. Increase the safety hazards of leakage points, simple installation, accurate and reliable, can be described as three birds with one stone.
4.Ultrasonic sensor for Oil/fuel level measurement
The External Ultrasonic Tank Level Sensor adopts explosion-proof design to meet explosion-proof requirements. The probe is installed externally, no need to open a hole in the container to be tested, real non-contact measurement, suitable for accurate liquid level of toxic, volatile, flammable, explosive, strong pressure, strong corrosive and other liquid media in various closed containers measuring. Therefore, the External Ultrasonic Tank Level Sensor is the best level measurement sensor for diesel, gasoline and other oil tanks. More about Diesel Fuel Level Sensor Types.
5. Other field applications
The External Ultrasonic Tank Level Sensor can be a good substitute for radar level gauges in some occasions where the dielectric constant is low, such as liquefied gas (dielectric constant <1.9) or the liquid surface contains a lot of bubbles and other radar level gauges are not suitable for use; For some highly corrosive acid and alkali storage tanks, such as liquid chlorine storage tanks, the External Ultrasonic Tank Level Sensor is also very useful.
External Ultrasonic Tank Level Sensor common available media include liquid chlorine, liquefied gas, liquid ammonia, ethylene, butadiene, gasoline, diesel, benzene, liquid bromine, hydrochloric acid, lye, nitric acid, methanol, vinyl chloride, hydrofluoric acid, ethylene Glycol, propane, naphtha, ethylene oxide, dimethyl ether.
Can External Ultrasonic Tank Level Sensors Detect Water Level?
Ultrasonic liquid level sensor can be used for water level measurement. The principle of ultrasonic reflection used. According to the contact between the sound wave emitted by the pool ultrasonic liquid level gauge and the liquid surface. According to the length of time it reflects back. To measure the height of the liquid level in the tank. Liquid level sensors are used in many sites to detect some conditions that require liquid level monitoring. It is well known that the liquid level of some sewage treatment tanks, the liquid level on the tank, the liquid level on the river channel and so on.
What is an ultrasonic level sensor?
Ultrasonic level sensor is a monitoring instrument for measuring liquid height, tank height, and material position.
Ultrasonic level sensor can adopt two-wire, three-wire or four-wire technology.
The two-wire system is: power supply and signal output are shared. The three-wire system is: the power supply circuit and the signal output circuit are independent. When using DC 24v power supply, a 3-core cable can be used, and the negative terminal of the power supply and the negative terminal of the signal output share a core wire. The four-wire system is: when using AC 220v power supply, or when using DC 24v power supply, when the power supply circuit and the signal output circuit are required to be completely isolated, a 4-core cable should be used. DC or AC power supply, 4~20mADC, high and low switch output.
There are 7 main types of level transmitters that Sino-Inst offers for water level indicate. Each type of transmitter works in a different way, and makes it useful for different types of processes.
Sino-Inst offers over 10 External Ultrasonic Tank Level Sensors and transmitters for level measurement. About 50% of these are liquid level meters, 40% is the level switches.
A wide variety of External Ultrasonic Tank Level Sensors and transmitters options are available to you, such as free samples, paid samples.
Sino-Inst is a globally recognized supplier and manufacturer of External Ultrasonic Tank Level Sensors and transmitters instrumentation, located in China.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
High Temperature & High Pressure level measurement, SIRD-705 GWR Level Sensor is a good choice. The highest pressure reaches 40MPa, and the highest temperature reaches 400℃.
The high temperature and high pressure guided wave radar level sensor is specially designed for high temperature and high pressure occasions. The product is mainly used for liquid level measurement on various boiler drums. Has high safety and accuracy. The highest rated pressure reaches 40MPa. The highest rated temperature reaches 400℃. It is suitable for high and low pressure heaters, condensers and deaerators in thermal power plants. As well as for liquid level measurement under high temperature, high pressure, vacuum and other steam conditions.
Sino-Inst offers a variety of Guided wave radar Level Sensors for industrial high temperature and high pressure level measurement. If you have any questions, please contact our sales engineers.
Features of GWR High Temperature Liquid Level Sensor
GWR Level Sensor has the advantages of low maintenance, high performance, high precision, high reliability and long service life. Compared with contact instruments such as capacitors and heavy hammers, it has unparalleled advantages.
The transmission of microwave signals is not affected by the atmosphere. Therefore, it can meet the requirements of harsh environments such as volatile gases, high temperature, high pressure, steam, vacuum and high dust in the process.
GWR Level Sensor is suitable for harsh environments such as high temperature, high pressure, vacuum, steam, high dust and volatile gases. It can continuously measure different material levels.
The main technical indicators of GWR Level Sensor meet or exceed similar products at home and abroad. It is easy to install and debug. It can be used alone or in a network. It can be widely used in metallurgy, building materials, energy, petrochemical, water conservancy, food and other industries.
GWR Level Sensor measurement advantages:
It has a strong ability to suppress steam and foam, and the measurement is not affected;
Not affected by liquid density, loose degree of solid material, temperature, and dust during feeding;
Low maintenance, high performance, high precision, high reliability and long service life.
Specifications of SIRD-705 GWR Level Sensor for High Temperature & High Pressure
GWR Level Sensor for High Temperature & High Pressure Applications
SIRD-705 GWR Level Sensor is suitable for measuring liquids with high pressure in sealed tanks, especially liquids in high temperature and high pressure environments.
It is suitable for high-pressure bubble water level measurement in power plants, liquid ammonia measurement, and liquid level measurement in chemical fertilizer synthesis ammonia process.
Advantages of using guided wave radar level sensors on boilers
Guided wave radar level sensor is often used in industrial production. Because of its superior performance, it is accepted by the public. It has the advantages of low maintenance cost, strong detection performance, accurate measurement accuracy, high safety, and long service life. The signal emitted by the device is not affected by the environment, atmosphere. So it can be used in a variety of special media, such as high temperature, high pressure, steam state, volatile gas, dust, vacuum environment, etc.
Guided wave radar level sensors in boilers
Today I want to share with you how to use the guided wave radar level sensor in the boiler. The high temperature and high pressure in the boiler need to use the level sensor to measure the internal liquid level to ensure its safety. The use of guided wave radar level sensors can solve the difficult problems of safety, accurate readings, and simple maintenance.
On some boilers, each boiler installation requires at least two independent water level sensors. Therefore, each boiler also needs to be equipped with two guided wave radar level sensors. Only in this way can the safety requirements for boiler operation be fully met. Guided wave radar level sensors need to use quartz tubes to observe changes in the liquid level in the furnace. However, the connecting pipes and valves need to be opened to improve the accuracy of detection. It is necessary to ensure that the probe and sensor are dry and clean during installation. If contamination occurs, it can not be wiped with a wet towel, and alcohol must be used for decontamination.
Although many cities do not yet have standard regulations on boiler level sensors. At least one intuitive level sensor must be installed, together with a guided wave radar level sensor for observation. If it is a large and complex complete set of boiler equipment, it is necessary to redesign and plan the guided wave radar level sensor and install it according to the design drawing.
Boilers usually use at least 2~3 sets of liquid level display systems according to their different sizes and uses. The selection of Level Transmitter is also different according to different requirements.
Direct liquid level display. The purpose is to observe the liquid level most intuitively. Commonly used plate level gauges, two-color level gauges, and magnetic flap level gauges are also commonly used on low-pressure and small-tonnage boilers;
Control Level Transmitter. It is used for automatic control signals. Usually a balance chamber is used to match a differential pressure transmitter. Immersion float level gauges are also commonly used. This type of level gauge requires the measurement principle to be directly related to the density of the medium to avoid boilers False liquid level effects;
Level Transmitter for safety. Electric contact water level gauge is mostly used. Its characteristic is to indicate the liquid level point by point. The points are not related to each other. Breaking a few points does not affect the display of other points. The reliability is extremely high.
The Non Contact Liquid Level Sensor is not in contact with the measured medium. The Non Contact Liquid Level Sensors provided by Sino-Inst is not Gravity Non-contact Liquid Level Sensors. It is the liquid level sensor used in industrial tanks, reservoirs, and open channels. There are mainly ultrasonic level sensors and radar level sensors.
The measurement temperature of most Ultrasonic Level Sensors currently on the market is -20 to +80°C.
So, can Ultrasonic Level Sensor measure high temperature and high pressure? The answer is no.
The ultrasonic level gauge can measure when the water surface is close to the probe, but cannot measure when the water surface is far from the probe. When the water temperature is low, the ultrasonic level gauge measures normally, but when the water temperature is high, the ultrasonic level gauge cannot measure. This is the measurement of the high temperature inside the pool or tank on site that affects the ultrasonic level gauge.
The reason why the E+H ultrasonic level gauge has this problem is that the liquid medium generally does not produce steam and mist below 30-40 °C. Above this temperature it is easy to generate steam or mist.
The ultrasonic wave emitted by the E+H ultrasonic level gauge will attenuate once as it passes through the steam during transmission. Attenuates again when reflected back from the liquid surface. As a result, the weak ultrasonic signal returns to the probe at the end and cannot be measured.
Moreover, in this environment, the probe of the ultrasonic level gauge is prone to form water droplets. It will hinder the transmission and reception of ultrasonic waves.
To solve this problem, we can have the following two operation options:
To increase the measurement range, the height of the water tank is actually 3 meters. The E+H ultrasonic level gauge between 6 meters and 9 meters should be selected. The effect of steam or fog on the measurement can be reduced or reduced.
The probe of E+H ultrasonic level gauge should be made of polytetrafluoroethylene or PVDF. Physically sealed. In this way, water droplets are not easy to condense on the emitting surface of the probe. As for the emitting surface of other materials, water droplets can easily condense.
High Temperature Level Switch refers to a liquid level switch that can measure and control liquid level under high temperature conditions.
High temperature float switches provide consistent and reliable switching points in high temperature and other extreme applications. These sensors are made of durable stainless steel floats that slide on stainless steel stems.
As the float moves over the heat-resistant internal switch, its built-in magnetic field activates the reliable switch.
The high temperature level switch can be mounted on the top of the tank, on the side of the tank, or from the bottom of the tank.
There is also a tuning fork level switch. Features of compact tuning fork level switch:
The temperature can reach 150 ℃, and it is used for general liquid level measurement at higher temperature.
Continuous level sensors are transmitters that measure liquids within a specified range. Level sensors determine the exact amount of liquid that provides a continuous analog signal. The level signal can be displayed directly on site or integrated into a process control or management system. These products can be installed vertically and horizontally. They are ideal for monitoring liquids in confined or restricted areas.
Common liquid level sensors are: Float type liquid level sensor, magnetostrictive liquid level sensor, Capacitive liquid level sensor, resistance liquid level sensor, Radar level sensor, laser level sensor, Ultrasonic liquid level sensor, pressure sensor, Bubble level sensor, isotope level sensor, Thermodynamic liquid level sensor Therhere are 7 main types of level transmitters that Sino-Instroffers. Each type of transmitter works in a different way, and makes it useful for different types of processes. More about level sensors from Wikipedia.
The liquid level sensor is a pressure sensor that measures liquid level. The static pressure input type liquid level transmitter is based on the principle that the measured liquid static pressure is proportional to the height of the liquid. It uses an isolated diffused silicon sensor or a ceramic capacitive pressure sensitive sensor to convert the static pressure into an electrical signal. Temperature compensation and linear correction are converted into standard electrical signals (usually 4～20mA/1～5VDC)
Float level sensor: Float level sensor is designed and produced based on the principle of buoyancy and static magnetic field. The position of a floating ball with a magnet (floating ball for short) in the measured medium is affected by buoyancy. The change of the liquid level causes the position of the magnetic float to change. The role of the magnet and sensor (reed switch) in the floating ball changes the number of components (such as fixed resistance) connected in series to the circuit. Thereby changing the electrical quantity of the instrument circuit system. That is, changes in the position of the magnetic float cause changes in the electrical quantity. The change of the electrical quantity is detected to reflect the liquid level in the container.
Sino-Inst offers over 10 Guided Wave Radar level transmitters for level measurement. About 50% of these are Radar level meters, 40% is the tank level sensor.
A wide variety of Guided Wave radar level meters options are available to you, such as free samples, paid samples.
Sino-Inst is a globally recognized supplier and manufacturer of Guided Wave radar level measurement instrumentation, located in China.
Request a Quote
Please enable JavaScript in your browser to submit the form
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Positive displacement flow meters are referred to as PD flow meters or PDF. They are the most accurate type in flow meters. Volumetric flow measurement uses a fixed small volume to repeatedly measure the volume of fluid passing through the flowmeter. It uses mechanical measuring elements to continuously divide the fluid into a single known volume part. The total flow volume is measured according to the number of times that the metering chamber is filled and discharged with the volume part of the fluid successively and repeatedly.
Positive Displacement Flow Meter Working Principle
In principle, PDF is a hydraulic engine that absorbs a small amount of energy from the fluid. This energy is used to overcome the frictional force of the flow detection element and the rotation of the accessories. At the same time, a pressure drop is formed at the inflow and outflow ends of the meter.
The working principle of a typical PDF (gear type) is shown in Figure 1.
The two shank round gears have a special shape that rolls to each other and rotates in contact. P1 and p2 represent the inlet pressure and the outlet pressure respectively, obviously p1>p2.
Figure 1(a) The lower gear is under the action of the two pressure differences. Produce counterclockwise rotation, which is the driving wheel; The upper gear has equal pressure on both sides. It does not produce a large rotating moment and is a driven wheel. Driven by the lower gear, it rotates clockwise.
In the position of Figure 1(b), both gears generate a rotational torque under the action of differential pressure and continue to rotate.
When rotating to the position in Figure 1(c), the upper gear becomes the driving wheel. The lower gear becomes the driven wheel. Continue to rotate to the same position as Figure 1(a) to complete a cycle.
One cycle action discharges the fluid volume of the four crescent-shaped cavities enclosed by the gear and the shell wall. This volume is called the “circulation volume” of the flow meter.
Suppose the circulation volume of the flow meter is u, and the number of gear rotations in a certain period of time is N. Then the volume of fluid flowing through the flowmeter during this time is V,
Then V=Nu(1)
The rotation of the Nanyuan gear is transmitted to the counter through the magnetic seal coupling and the transmission reduction mechanism to directly indicate the total amount flowing through the flowmeter.
If the sending device is attached and then equipped with an electric display instrument, it can realize that the remote transmission is only the instantaneous flow or the cumulative flow.
Although there are many segmentation methods to form various forms of PDF, most of them have similar basic characteristics.
The main reason for the PDF error is the leakage of the gap between the movable measuring piece and the static measuring chamber that divides a single fluid volume.
One of the reasons for leakage is to overcome the frictional resistance of moving parts. The second is the effect of pressure drop formed by the hydraulic resistance of the instrument.
PDF has high measurement accuracy, the basic error is generally ±1%R, and the special one can reach ±0.5%R or higher. Usually used in expensive media or where precise metering is required.
PDF has no effect on the metering accuracy when the flow velocity field of the rotating flow and the pipe blocker is distorted, and there is no requirement for the straight pipe section in front. This is of great significance in field use.
PDF can be used for the measurement of high viscosity fluids. The range is wide, generally 10:1 to 5:1, and special can reach 30:1 or more.
PDF is a direct-reading instrument that does not require external energy, and can directly obtain the cumulative total, which is clear and easy to operate.
Positive displacement flow meter types
There are many types of PDF, which can be classified according to different principles. According to the structure of the measuring element, there are the following types: 1) Rotor type 2) Scraper type 3) Rotating piston type 4) Membrane type, etc.
Positive displacement flow meter advantages and disadvantages
Advantages
PDF measurement accuracy is high, the basic error is generally ±0.5%R, and the special one can reach ±0.2%R or higher. Usually used inexpensive media or occasions requiring precise measurement.
PDF has no effect on the measurement accuracy when the flow velocity field of the rotating flow and the pipe choke is distorted, and there is no requirement for the front straight pipe section. This is of great significance in on-site use.
PDF can be used for the measurement of high-viscosity fluids.
The range is wide, generally 10:1 to 5:1, and special can reach 30:1 or more.
PDF is a direct-reading instrument without external energy. The cumulative total can be directly obtained, which is clear and easy to operate.
In the indirect mass flow measurement combined with volumetric flowmeters, PDF is compared with volumetric flowmeters derived from velocity equations. The volume is a direct geometrical quantity. The influencing factors of the volumetric quantity are simpler.
In the measurement of high-pressure natural gas that is not suitable for density meter measurement, the compression coefficient of difficult-to-handle gas can be obtained indirectly with PDF.
Disadvantages
The PDF structure is complex, bulky, and heavy, especially the larger-diameter PDF is bulky. Therefore, it is generally only suitable for small and medium-sized.
Compared with several other types of general flow meters (such as differential pressure, float, electromagnetic). PDF’s measured medium types, medium working conditions (temperature, pressure), and caliber limitations are larger, and the scope of application is narrow.
Due to the thermal expansion and deformation of parts at high temperatures, and the brittleness of materials at low temperatures, PDF is generally not suitable for high and low temperature applications. At present, the usable temperature range is roughly -30~+160℃, and the maximum pressure is 10MPa.
Most PDF instruments are only suitable for clean single-phase fluids. When particles and dirt are contained, a filter must be installed upstream, which will increase the pressure loss and increase maintenance work. For measuring liquids containing gas, a gas separator must be installed.
PDF security is poor. If the detection moving parts are stuck, the fluid cannot pass through, and the cut-off piping system cannot be used. However, some structural designs (such as Instromet’s waist wheel flowmeter) have a built-in bypass in the housing. When the detection moving element is stuck, the fluid can pass through the bypass.
The volumetric flowmeter should be installed and used in accordance with the standard flow range, nominal pressure and flow direction marks on the nameplate.
The positive displacement flowmeter should work under the condition that the fluid temperature is -20~+120℃ and the ambient temperature is -20~+55℃ and the relative humidity of the environment is not more than 80%.
When the positive displacement flowmeter leaves the factory, it is calibrated with water at room temperature. If the measured fluid is different from the water at room temperature,the constant should be corrected or re-calibrated with the actual measured fluid, but for fluids with a viscosity less than 5×10-6m2/s (5Mpa.s), there is no need to re-calibrate.
Under normal circumstances, the service life of positive displacement flowmeters is generally from six months to one year, depending on the severity of the working conditions. And should be removed and washed regularly. If the shaft or bearing is found to be severely worn, it should be replaced and re-calibrated.
The Sanitary Positive Displacement Flow Meter is made of stainless steel and is quickly connected by Tri-clamp. Can be used to measure viscous liquids in the food industry. Such as sweeteners, edible oil, palm oil, honey, fat, tallow, fat, syrup, molasses, etc.
Gas Roots flowmeter is an instrument that accurately measures gas flow, based on the principle of volumetric measurement. For accurate metering of gas flow through closed pipes.
The flowmeter is composed of two parts: Roots flow sensor and display instrument. It can be used to measure non-corrosive gases such as natural gas, city gas, propane, nitrogen, and industrial inert gases. Mainly used in gas business settlement in catering, hotel and other industries. Gas metering for transmission and distribution network, gas pressure regulating station metering, industrial and civil boilers and other gas metering. Can also be used as a standard flow meter.
Rotary positive displacement gas flow meter is mainly composed of flow meter body, rotating element, electronic display device or mechanical display device.
There is a metering chamber within the housing of the flowmeter. There are one or two pairs of rotating elements that can rotate tangentially.
A pair of drive gears are mounted coaxially with the two rotating elements outside the flowmeter housing. They mesh with each other. Thereby, the mutual linkage of the two rotating elements is realized.
For each revolution, a fixed amount of gas is expelled.
The number of revolutions of the rotating element is recorded, based on the volume of the metering chamber space (cycle volume). The volume of gas flowing through the flowmeter can be obtained.
Positive displacement flow meter vs turbine
A turbine flowmeter has the characteristics of simple structure, lightweight, simple maintenance, and adaptability to high parameters (high temperature, high pressure, and low temperature). Turbine flowmeters are currently mainly used in the measurement of natural gas, coal gas, petroleum, organic liquids, inorganic liquids, cryogenic fluids, liquefied gas, and other media.
So is the turbine flowmeter a positive displacement flowmeter?
A turbine flowmeter is not a positive displacement flowmeter, but a velocity flowmeter. Turbine flow meters, positive displacement flow meters and Coriolis mass flow meters are three types of flow meters with excellent repeatability and accuracy.
Sino-Inst, Manufacturer for Positive Displacement Flow Meters. For example crude oil flow meter, diesel flow meter, gasoline flow meter.
Sino-Inst’s Positive Displacement Flow Meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, US, and other countries.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
The ultrasonic liquid level sensor is a non-contact measuring device. That can send and receive high-frequency sound waves to measure the distance to the surface of liquid-based materials.
The ultrasonic liquid level measurement uses the non-contact principle. It is most suitable for level measurement of hot, corrosive, and boiling liquids. It is used to measure liquid levels. Ultrasonic equipment that converts it into electrical signals to send to other instruments.
Sino-Inst offers a variety of ultrasonic liquid level sensors and transmitters for continuous, non-contact tank level measurement. If you have any questions, please contact our sales engineers.
The liquid level sensor is a pressure sensor that measures liquid level. The static pressure input type liquid level transmitter is based on the principle that the measured liquid static pressure is proportional to the height of the liquid. It uses an isolated diffused silicon sensor or a ceramic capacitive pressure sensitive sensor to convert the static pressure into an electrical signal. Temperature compensation and linear correction are converted into standard electrical signals (usually 4～20mA/1～5VDC)
The working principle of the ultrasonic level gauge: The high-frequency pulse sound wave emitted by the ultrasonic transducer is reflected on the surface of the measured level, and the reflected echo is received by the transducer and converted into an electrical signal. The propagation time of the sound wave is proportional to the distance from the sound wave to the surface of the object. The relationship between sound wave transmission distance S and sound speed C and sound transmission time T can be expressed by the formula: S=C×T/2.
According to the characteristics of ultrasound, it is actually more suitable for occasions where the accuracy requirements are not high and the working environment is not harsh.
Water treatment industry.
Water treatment industry, including sewage treatment, tap water, pure water manufacturing and other occasions.
The measured medium is basically sewage and clean water, which does not require high measurement accuracy. And the working environment is basically not corrosive, there is no electromagnetic interference, and most of them work in the open air. At most, large waves are encountered where the water enters, or there is a small amount of foam on the water surface.
Water conservancy and hydrology Water conservancy and hydrology industry.
In the early years, it was mainly used to measure water level changes at the gate. In recent years, because the state has increased its investment in the water conservancy industry. Flash flood warnings and water level and rainfall monitoring must be carried out in small and medium river basins.
These occasions basically need 24VDC power supply and RS485 output.
Because they are all measured on the water surface, there is no requirement for the launch angle of the ultrasonic level gauge. There will be no volatility and foam influence.
It is generally carried out on a relatively wide channel. Small channels generally do not need to be measured.
The common channel width is more than 1 meter.
4. Chemical companies mainly need anti-corrosion and explosion-proof ultrasonic level gauges.
Liquids in chemical companies are measured by ultrasonic waves, which are basically in storage tanks.
For example: sulfuric acid, hydrochloric acid, liquid caustic soda, toluene, xylene, olefin, ammonia, acetone, etc. These occasions can be solved with an ultrasonic level gauge. If it is in the reactor, it will be affected by stirring.
There should be no obstacles under the sound wave. Because the ultrasonic level sensor uses the principle of sound wave reflection to achieve liquid level measurement. If there are obstacles, it will affect the ultrasonic emission. It will cause signal loss and affect the measurement effect.
The measurement of ultrasonic level sensor is prone to blind spots. This is because in the ultrasonic pulse transmission process. Because the mechanical inertia occupies the transmission time. Therefore, the small area near the ultrasonic transducer cannot receive the sound wave. The area that cannot be measured is called the blind zone. The size of the blind zone is related to the ultrasonic measurement distance. The smaller the measuring distance, the smaller the blind zone. The larger the measuring distance, the larger the blind zone.
The measurement of ultrasonic level sensor is easily affected by temperature. In actual measurement, changes in temperature will cause changes in the speed of sound. This will lead to errors in the measurement.
It is not suitable to measure pressure vessels. Because the pressure mainly affects the probe. And there is a certain relationship between pressure and temperature. Pressure changes will affect the temperature changes, which in turn affects the speed of sound. The accuracy of the measurement is affected.
Radar Level Transmitter is an application of microwave (radar) positioning technology in level measuring instruments. It transmits energy waves through a device that can emit energy waves (usually pulse signals). The energy waves are reflected when they encounter obstacles, and the reflected signals are received by a receiving device.
According to the time difference of the energy wave movement process, the level change can be determined. The microwave signal is processed by the electronic device. Finally, the microwave signal is converted into an electrical signal related to the level.
The basic principle of ultrasonic measurement of liquid level is: the ultrasonic pulse signal sent by the ultrasonic probe propagates in the gas, and is reflected after encountering the interface of air and liquid. After receiving the echo signal, calculate the propagation time of the ultrasonic wave. Convert the distance or liquid level height.
Common Applications for Ultrasonic Liquid Level Sensors
Ultrasonic liquid level sensor integrates three functions of non-contact switch, controller and transmitter. Suitable for small storage tanks. In integrated systems or replace float switches, conductivity switches and static pressure sensors. It is also suitable for integrated applications in fluid control and chemical supply systems. for machinery, brakes and other equipment The application of small storage tanks is also a good choice.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Guided Wave Radar Level Transmitter with Coaxial tube type antenna is used to measure & control liquid with low permittivity. Contact measurement.
Guided wave radar level transmitters equipped with Coaxial Probe are used in liquids. Especially liquids with low dielectric constant. For example: non-ionized water, deoxygenated water and other liquid measurement. If the dielectric constant of the liquid is too low, radar level sensors are not suitable. Coaxial Probe Guided Wave Radar Level Transmitter can measure and control the level of liquids with low electrical constants or surface fluctuations. Signal output (4～20) mA/HART.
Sino-Inst offers a variety of Guided wave radar Level Sensors for industrial level measurement. If you have any questions, please contact our sales engineers.
Features of Coaxial Probe Guided Wave Radar Level Transmitter
Applicable medium: liquid. Especially liquid with low dielectric constant. It can measure any medium with a dielectric constant greater than or equal to 1.4.
Generally used to measure the medium with viscosity ≤ 500cst and not easy to produce adhesion.
The maximum range of rod radar can reach 6 meters.
It has a strong ability to inhibit steam and foam, and the measurement is not affected.
For liquid materials with a relatively small dielectric constant. A double probe type measurement method can be used to ensure good and accurate measurement.
From an antenna perspective, there are roughly three types of guided wave radar level transmitters for tank level measurement. Rod-type, cable-type, and coaxial probe-type.
For rod-type and cable-type, please refer to the product page. Here, we will focus on the Coaxial Probe Guided Wave Radar Level Transmitter.
The antenna of the coaxial probe-type guided wave radar level transmitter mainly consists of two parts: a metal circular tube and a metal rod. To prevent the metal rod from touching the inner wall of the metal circular tube and causing interference. A fixing method must be used inside the tube.
In addition, circular holes are distributed on the metal circular tube. Which are used for the inflow of liquid medium in the tank.
The radar wave emitted by the coaxial probe-type guided wave radar level transmitter propagates in the space inside the metal circular tube. And the effective echo signal is stronger, resulting in more accurate measurement. Therefore, this measurement method is more suitable for measuring the level of liquids with low dielectric constants. Many deionized water and ion-free water level measurements will first consider this measurement method.
In addition, the special antenna structure of the coaxial probe-type guided wave radar level transmitter has strong anti-interference ability and is not easily affected by external factors. For certain special working conditions, this measurement method is more effective.
Furthermore, the coaxial probe-type guided wave radar level transmitter can complete measurements in small spaces and high temperature and pressure environments, making it more adaptable to different environments.
Finally, it has been documented that the coaxial probe-type guided wave radar level transmitter can be used to measure the height of different liquid interfaces. As different liquids have different dielectric constants. The radar wave emitted by the level transmitter encounters the interface and reflects back. Allowing for the theoretical possibility of measuring the position of different liquid interfaces.
In summary, from the above content, we can see that the coaxial probe-type guided wave radar level transmitter has a more concentrated energy, less interference. And more accurate measurement compared to other guided wave radar level transmitters.
Here, we introduce the relatively common debugging methods and means of guided wave radar level transmitters. Users can determine the most appropriate method of use according to their actual situation. Finally proceed. Remember to be cautious when choosing a method, otherwise errors will easily occur.
Via HART handheld programmer. However, the HART handheld programmer has its adjustment range, which is not suitable for all products. The measurement range is 4-20mA corresponding value.
Through the handheld adjustment module. Its function is equivalent to an analysis and processing instrument. The programmer is composed of buttons and a liquid crystal display. The adjustment menu and parameter settings can be displayed.
Through the debugging software. Guided wave radar level gauge can be debugged through software. The process is: mainly use HART software for debugging, and an instrument driver is needed. Among them, when using software for debugging, power up the radar instrument with 24VDC. At the same time, add a 250 ohm resistor to the front end of the HART adapter. If the integrated HART resistance power supply meter, the internal resistance is 250 ohms. There is no need to add an external resistor. At this time, the HART adapter can be connected in parallel with the 4–20mA line.
Guided wave radar level transmitter is a type of level measurement device that uses high frequency radar pulses guided along a probe to determine the level of a liquid or solid in a container. The radar pulses are reflected back to the transmitter by the liquid or solid. And the time delay between the transmission and reception of the pulses is used to calculate the level. The probe can be inserted into the container or mounted externally. And is suitable for use in a wide range of industries, including oil and gas, chemical processing, and food and beverage.
The main difference between radar and guided wave radar level transmitters lies in the way they transmit and receive the radar signal.
Guided wave radar level transmitters, on the other hand, use a probe or cable that is inserted into the liquid or solid material being measured. The radar signal is guided along the probe or cable, and reflected back to the transmitter by the surface of the material.
Guided wave radar level transmitters are typically used for measuring level in smaller tanks or vessels, or in situations where the material being measured has low reflectivity or is highly viscous.
The range of a guided wave radar level transmitter can vary depending on the specific device and its application. But generally ranges from a few centimeters to over 30 meters (100 feet). The range of the transmitter is determined by the length of the probe or antenna used. The dielectric constant of the material being measured. And the strength of the transmitted signal. In some cases, the range of the transmitter can be extended through the use of specialized probes or antennas or by using multiple devices in tandem.
Because the general testing distance of radar level transmitters is usually 2-10m or more than 10m. It is difficult to simulate the distance required for calibration in the laboratory. Therefore, radar level gauges mostly use online calibration. However, on-line routine calibration must use on-site process conditions. During the calibration period, on-site process equipment-storage tanks or reaction tanks must be shut down, which seriously affects on-site process production. At the same time, the on-site liquid level change is affected by the process conditions and the stabilization time is too long, so the online routine calibration time is usually longer. Extended reading: Applications of Radar Corrosive Liquid Chemical Level Sensor
Guided wave radar level transmitter price
The price of guided wave radar level transmitters can vary depending on several factors. Including the manufacturer, the model, the range, and the features of the device. Generally speaking, guided wave radar level transmitters are more expensive than other types of level measurement devices. Such as ultrasonic or capacitance level sensors, due to their advanced technology and accuracy.
Prices can range from a few hundred dollars to several thousand dollars per unit, depending on the specifications of the device.
In addition to the cost of the transmitter, there may be additional costs for installation, calibration, and maintenance.
While guided wave radar level transmitters can be a significant investment, they offer many benefits. Including improved accuracy, reliability, and versatility, which can make them a valuable asset in many industries.
Sino-Inst Guided wave radar level transmitter, made in China. Has a good product quality and price advantage. The price of our Guided wave radar level transmitter ranges from USD400-800.
The specific product price needs to be determined according to the actual product parameters. So, if you need a quotation for Guided wave radar level transmitter, please contact our sales engineer in time. Provide your measurement requirements, and you can get the price of Guided wave radar level transmitter within 24 hours.
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Sino-Inst offers over 10 Guided Wave Radar level transmitters for level measurement. About 50% of these are Radar level meters, 40% is the tank level sensor.
A wide variety of Guided Wave radar level meters options are available to you, such as free samples, paid samples.
Sino-Inst is a globally recognized supplier and manufacturer of Guided Wave radar level measurement instrumentation, located in China.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Solid Level Sensor continuously detects changes in the level of solid materials. Monitor and Indicate the level of bulk solids in silos, storage tanks, or other containers.
A solid Level Sensor is very important for the production process. Fly ash powder measurement. Chemical plant level measurement. Cement silo powder measurement. Controlling the change of material level can maximize the efficiency, prevent overflow, exhaust, or track the volume or mass. SIRD-703 GWR Bulk Solids & Powder Solid Level Sensor is mainly suitable for solid powder level measurement.
Sino-Inst offers a variety of Solid Level Sensors for industrial level measurement. If you have any questions, please contact our sales engineers.
Solid Level Sensor is mainly divided into two categories: continuous type and switch type continuous type. Continuous type includes ultrasonic wave and guided wave radar. There are many types of switches. Rotary resistance, tuning fork, capacitance, heavy hammer, RF admittance.
Features of SIRD-703 GWR Solid Level Sensor
The guided wave radar level meter is highly versatile. It is suitable for the measurement of acids, alkalis or other corrosive media
Anti-hanging material. The unique circuit design and sensor structure of the guided wave radar level meter make its measurement not affected by the hanging material of the sensor. No regular cleaning is required to avoid false measurements.
Maintenance-free. The guided wave radar level gauge has no moving parts during the measurement process. There is no damage to mechanical parts and no maintenance is required.
Anti-jamming. Contact measurement by guided wave radar level meter. Strong anti-interference ability, can overcome the influence of steam, foam and stirring on the measurement.
Accurate and reliable. The measurement volume of the guided wave radar level gauge is diversified, which makes the measurement more accurate. The measurement is not affected by environmental changes, with high stability and long service life.
Solid level measurement is the measurement of the position of the solid block or powder surface in the silo to know the amount of material stored in the silo.
The device that detects Solid level is called Solid Level Sensor.
Solid Level Sensor refers to an instrument that detects changes in the height of solid materials in a container in real time.
Solid Level Sensor is also known as level transmitter, level controller, level meter, level meter, etc.
The Advantages and Disadvantages of GWR Bulk Solid Level Sensor
Guided wave radar liquid level gauge is a contact type liquid level gauge. Its working principle is to use electromagnetic waves to transmit signals-reflect-receive signals. Unlike conventional radar level gauges, guided wave radar requires a medium to transmit signals. This medium can be a rod or a cable, depending on the installation environment. So what are the advantages and disadvantages of the guided wave radar level gauge compared with other level gauge products? Let us explain for you.
Advantage:
Can measure a variety of different media. Including liquid, solid, particles, powder, etc., and will not be affected by the density or temperature of the media.
Continuous measurement, safe, stable and reliable.
For the medium with a low dielectric constant, a guide rod can be added to improve the accuracy of the measured data.
The fluctuation of the level has little effect on the measurement results.
The signal is stable and the anti-interference ability is strong.
Vapor or foam will basically have no effect on the measured data.
Two output modes of 4~20 or digital signal adapt to different installation environments.
Guided wave radar level sensors have various materials, process connections, probe types and accessories to provide this option.
Guided wave radar level sensor is suitable for small storage tanks, storage tanks with complex geometric shapes, and when there are obstacles in the tanks. It is not affected by the mechanical design of the bypass pipe. Thereby minimizing the risk of leakage.
Disadvantages:
Because it is a contact measurement, for those flammable and explosive media, a higher explosion-proof level is needed to deal with it.
Compared with the non-contact horn radar level sensor, the guided wave radar level sensor directly comes into contact with the measured medium. Therefore, the daily maintenance of the guide rod is relatively more.
The volume is relatively large, and transportation is not convenient.
If measuring a solid medium, the medium needs to be kept horizontal. And the dust can not be much, otherwise it will affect the measurement accuracy.
The measuring guide rod or cable is easy to foul, and it needs to be cleaned regularly.
The price is higher than other level sensor products.
Solid state-level sensors perform real-time detection of changes in the height of solid materials in the container. Solid state-level sensors are also called level transmitters, level controllers, bulk solid level sensors, dry material level sensors, etc.
Solid state-level sensors are mainly divided into two categories: continuous type and switch type.
Continuous type includes ultrasonic and guided wave radar.
There are many types of switch type, resistance rotary type, tuning fork type, a capacitive type, heavy hammer type, RF admittance.
Among them, the resistance-rotation and tuning-fork level gauges have high requirements on the use occasions, and are not resistant to impact, and cannot measure viscous materials.
The capacitive type should be said to overcome the shortcomings of other level gauges, but it cannot identify fake materials. In order to overcome this defect, a radio frequency admittance level meter was developed on the basis of capacitance.
The solids measurement technology is usually from top to bottom, with a level gauge mounted on the top of the container pointing downwards to the material. The three types of level meters are guided wave radar, non-contact radar, and sonar radar that use probes to measure pulse travel.
Each technology has its own particularity, mainly related to the characteristics of how to deal with solids. Under normal circumstances, calculations for all three measurements are based on the time required for the energy pulse to be emitted to a certain point on the surface of the material and then return to the meter.
Guided wave radar is a very small point. The diameter of the meter probe is only 1 or 2 inches. With only one point, the meter cannot measure the entire surface profile. But for some applications, one point is enough to receive information. Non-contact radar and sonic level meters, especially the latter, although they can measure a large area, may still produce an incomplete image. Whether this is sufficient depends on the needs of different application processes.
The non-contact radar instrument emits electromagnetic pulses. When the pulse encounters the boundary where the dielectric constant changes, part of the energy is reflected back. In this case, the boundary is the interface between the air above the container and the surface of the material in the container. These materials can be solid or liquid. The higher the dielectric constant of the material, the stronger the reflection.
When measuring the solid material level, the surface angle can cause a problem. If the surface of the material is level, the energy will be directly reflected back into the meter. However, if the pulse encounters an inclined material, part of its energy will be reflected to the side of the container and cannot be captured. In most cases, the transmitted signal is strong enough to be measured. But if the material has a low dielectric constant and a high angle of repose, this combination is more difficult. In solid applications, algorithms for specific materials on meters and parabolic antennas can help to measure solid material levels.
Acoustic instruments have a similar but different constraint. The sound pulse or sound wave emitted by the instrument passes through the air and reaches the surface of the material in the container or the container wall. The intensity of the reflection depends on the bulk density of the material, that is, the mass of the material in a given volume. Therefore, if the surface of the material is rough, it will absorb part of the energy and the reflected wave will be weakened.
ultrasonic level sensor for solids
Ultrasonic Level Sensing sensors and transmitters are used for continuous, non-contact level measurement.
Multiply the time from ultrasonic transmission to reception by the speed of sound to calculate the height of the material level. Since the air temperature will affect the speed of sound wave propagation, the air temperature needs to be measured to correct the speed of sound. The ultrasonic level meter is suitable for measuring the block material level with larger granularity.
The top of the storage warehouse is equipped with an ultrasonic generator and a receiver. The ultrasonic wave emitted by the generator is reflected by the air layer to the material surface, and part of the reflection is received by the receiver.
Capacitive level sensor for solids
In general, capacitive level gauges are not affected by the environment such as vacuum, temperature, and pressure. Firm structure, convenient installation, easy maintenance, and low price.
However, capacitive level gauges have certain limitations in use. There are many types of capacitive level gauges. It can measure both conductive and non-conductive media. It can also measure the liquid level of high-speed containers caused by tilting and shaking.
The medium requirement of the measured object of the capacitive level meter is not as strict as other meters. It can not only control the liquid level but also continuously measure, so it can be regarded as a common measuring instrument.
When measuring continuous liquid levels, concentric cylindrical capacitors are generally used. In principle, cylindrical capacitive object flow meters can detect the level of conductive liquids. It can also detect the level of solid particles.
If the medium to be measured is a conductive liquid, the circular electrode will cause a short circuit in the conductive liquid. Therefore, when measuring the level of conductive liquids, the electrodes must be covered with insulators.
Radar level transmitters use radar technology to perform the non-contact continuous level measurement. The radar level indicator converts the level into an electrical signal. The level signal output can then be utilized by other instrumentation to monitor or control. Liquids and solids are commonly measured with this measuring technique. Like: Fly ash silo. Radar level sensors are divided into: Pulsed radar technology and frequency modulated continuous wave (FMCW) radar level sensors.
Point level measurement sensors are used to mark a single discrete liquid height–a preset level condition. Generally, this type of sensor functions as a high alarm, signaling an overfill condition, or as a marker for a low alarm condition. Like Float Level Sensors.
Our common liquid level transmitters can be used to measure the water level. However, from a cost perspective, the hydrostatic level transmitter is most commonly used to measure the water level.
Common liquid level sensors are: Float type liquid level sensor, magnetostrictive liquid level sensor, Capacitive liquid level sensor, resistance liquid level sensor, Radar level sensor, laser level sensor, Ultrasonic liquid level sensor, pressure sensor, Bubble level sensor, isotope level sensor, Thermodynamic liquid level sensor There’re are 7 main types of level transmitters that Sino-Instroffers. Each type of transmitter works in a different way and makes it useful for different types of processes.
The Level sensor is a common sensor that measures the liquid level position. It converts the height of the position into an electrical signal for output.
An instrument that detects changes in the height of solid materials in a container in real time is called a level gauge.
Material level meter is also called material level transmitter, material level controller, material level meter, material level meter and so on.
80 GHz Radar Level Measurement 80GHZ Radar Level Transmitter refers to a frequency modulated continuous wave (FMCW) radar product operating at 76-81GHz. It can be used for level measurement of solids and…
The material level indicator refers to an instrument for real-time detection of changes in the height of solid materials in a container. Material level indicator is also known as material level transmitter,…
Float Switch for Water Tank is a switch that can adjust the liquid level status of water tanks, buckets, pools and other fields. It can also be used to control and protect…
Water level control refers to the control of high and low water levels by mechanical or electronic methods. It can control solenoid valves, water pumps, etc. to become an automatic water level…
What Is Radar Type Level Transmitter? The Radar Type Level Transmitter is a kind of instrument that measures the liquid level in the container by microwave. The Radar Type Level Transmitter provides…
Wastewater level sensor occupies a large proportion in sewage treatment applications. It is used in almost all aspects of sewage treatment. In sewage treatment, the level of waste water, sludge, chemical solutions,…
Tank level gauges are instruments used to indicate and control the height of the liquid level in the tank. Commonly used in water storage tanks, oil storage tanks, and underground tanks. Tank…
What is a magnetic type level gauge? A magnetic Level Gauge is also called a magnetic level indicator. Magnetic Level Gauge is developed based on the principle of buoyancy and magnetic effect…
Non-contact radar level sensor Radar level sensors are used for continuous non-contact level measurement of liquids or solids. And convert it into electrical signals. The radar level sensor emits high-frequency radio frequency…
Radar level transmitter and Ultrasonic level transmitter are both liquid level measuring instruments. The most obvious difference is that one uses electromagnetic waves and the other uses ultrasonic waves. So, besides that,…
What is a capacitive liquid level sensors? Capacitive liquid level sensor is an instrument for continuous measurement of liquids and converting it to an electrical signal. Capacitive liquid level sensors play a…
Sulfuric acid storage tanks are mainly used to store sulfuric acid produced in acid production. The accuracy of the liquid level of the sulfuric acid storage tank is directly related to the…
The capacitive fuel level sensor refers to a capacitive liquid level transmitter used to measure the oil level. According to the principle of capacitance sensing, when the height of the measured electrode…
A capacitive water level sensor is often used to measure the water level of the water storage tank. The capacitive water level sensor uses the change of measuring capacitance value to measure…
Sino-Inst offers over 10 GWR Bulk Solids & Powder Solid Level Sensors for level measurement. About 50% of these are float liquid level meters, 40% is the level switches.
A wide variety of Solid Level Sensors options are available to you, such as free samples, paid samples.
Sino-Inst is a globally recognized supplier and manufacturer of Solid Level Sensors instrumentation, located in China.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Liquid chemical level sensor is suitable for chemical storage tanks or chemical processing. Especially for highly corrosive liquids.
In chemical storage tanks or chemical processes, there is a risk of corrosive liquids and explosions. Therefore, the requirements for the liquid level indicator are extremely high. SIRD-702 liquid chemical level sensor is a corrosion-resistant guided wave radar level sensor. The maximum range of anti-corrosion guided wave radar level meter can reach 20 meters. It is used to measure the liquid of strong acid and strong alkali. Such as hydrochloric acid, sulfuric acid, hydrofluoric acid, strong alkali and sodium hydroxide. SIRD-702 liquid chemical level sensor adopts all PTFE sealed cable or rod antenna.
Sino-Inst offers a variety of Liquid Chemical Level Sensors for industrial level measurement. If you have any questions, please contact our sales engineers.
Features of Corrosive Liquid Chemical Level Sensor
The guided wave radar level meter is highly versatile. It is suitable for the measurement of acids, alkalis or other corrosive media
Anti-hanging material. The unique circuit design and sensor structure of the guided wave radar level meter make its measurement not affected by the hanging material of the sensor. No regular cleaning is required to avoid false measurements.
Maintenance-free. The guided wave radar level gauge has no moving parts during the measurement process. There is no damage to mechanical parts and no maintenance is required.
Anti-jamming. Contact measurement by guided wave radar level meter. Strong anti-interference ability, can overcome the influence of steam, foam and stirring on the measurement.
Accurate and reliable. The measurement volume of the guided wave radar level gauge is diversified, which makes the measurement more accurate. The measurement is not affected by environmental changes, with high stability and long service life.
Specifications of SIRD-702 GWR Corrosive Liquid Chemical Level Sensor
Suitable for Medium:
Liquid, especially corrosive liquids
Application:
Acids, bases or other corrosive media
Explosion-proof Grade:
Exia IIC T6 Ga/Exd IIC T6 Gb
Measuring Range：
20m
Frequency:
500MHz-1.8GHz
Antenna:
Full PTFE sealing cable type or rod antenna
Accuracy:
±10mm
Process Temperature:
（-40～200）℃
Process pressure:
（-0.1～0.3）MPa
Signal output:
（4～20）mA/HART
The Scene Display:
Four LCD/Can be programmed
Power Source:
Two-wire (DC24V) ； Four-wire（DC24V/AC220V）
Shell:
Aluminum /Plastic
Connection:
Flange (optional) / Thread
What is the best method for sensing the level of a corrosive liquid in a tank
If the user’s tank can be perforated. Then choose guided wave radar liquid level sensor, use corrosion-resistant material. It is the most cost-effective option.
If the user’s tank cannot be perforated. Then it is the best choice to choose an externally attached ultrasonic liquid level meter. Because the sensor can be directly attached to the bottom and side of the tank. No need to cut holes, easy to install. But the cost will be a little higher.
External Tank Level Indicator refers to an externally mounted level sensor. It is used to install on the outside of the liquid storage tank to measure the liquid level of the tank. When measuring with External Tank Level Indicator, install the ultrasonic probe just below the outer wall (bottom) of the container under test. No need to cut holes, easy to install. Does not affect on-site production. It can realize accurate measurement of various toxic substances and various pure liquids in high temperature and high pressure airtight containers.
Ultrasonic Tank Level Sensors
Ultrasonic Level Sensing is a low-cost liquid level measurement technology. Ultrasonic Level Sensing sensors and transmitters are used for tank or river level measurement. Ultrasonic Level Sensing does not need to contact the medium, can be continuously measured, low cost. Therefore, Ultrasonic Level Sensing is very popular among users. Ultrasonic liquid level sensors are available in general and intrinsically safe types. Output 4~20mA standard signal or output the measurement result to the secondary meter through RS-485. Meets the system’s automatic control.
Float Switch Level Sensors for chemical processing
Float level sensors are continuous level sensors. Float level gauges use magnetic floats as measuring elements. magnetic float that rises and falls as liquid levels change. The movement of the float will generate a magnetic field. The sensor’s internal resistance changes linearly, and the intelligent converter converts the resistance change into a 4~20mA standard current signal. It can display the liquid level percentage, 4~20mA current and liquid level value on the spot. It can also output the switching value signal to conduct liquid Bit switch control.
A submersible level transmitter made of PTFE is perfect in the harshest applications. Like Acid and alkali environment, Sludge and Slurries. Anti-corrosive Submersible Level Transmitter utilizes the linear change law of liquid height, density, and pressure. It converts the change of liquid level into linear 4-20mADC standard signal output. Integrate temperature compensation calibration technology. Easy installation. Anti-corrosive Submersible Level Transmitter adopts a two-wire system. 4 ～ 20mA output. 24V DC power supply. ATEX, 3 wire, remote mount transmitter optional.
Common liquid level sensors are: Float type liquid level sensor, magnetostrictive liquid level sensor, Capacitive liquid level sensor, resistance liquid level sensor, Radar level sensor, laser level sensor, Ultrasonic liquid level sensor, pressure sensor, Bubble level sensor, isotope level sensor, Thermodynamic liquid level sensor There’re are 7 main types of level transmitters that Sino-Instroffers. Each type of transmitter works in a different way and makes it useful for different types of processes.
1. Flow sensor is a kind of detection instrument used to detect the flow parameters of liquid, gas and other media and convert it to other forms of signals for output. The flow sensor has many advantages such as small size, lightweight, intuitive and clear reading, high reliability, and no pressure loss. 2. Level sensor is a sensor that can replace manual measurement. The liquid level sensor can convert the height of the liquid level into an electrical signal for output, so as to achieve the purpose of controlling the liquid level.
Ultrasonic Level Sensing is a low-cost liquid level measurement technology. Ultrasonic Level Sensing sensors and transmitters are used for tank or river level measurement. Ultrasonic Level Sensing does not need to contact the medium, can be continuously measured at, low cost. Therefore, Ultrasonic Level Sensing is very popular among users. Ultrasonic liquid level sensors are available in general and intrinsically safe types. Output 4~20mA standard signal or output the measurement result to the secondary meter through RS-485. Meets the system’s automatic control.
The liquid level sensor converts the liquid level signal in the container into a switch signal or a voltage and current signal. Then through the external circuit, the measurer can intuitively know the liquid level in the container accurately.
Sino-Inst offers over 10 GWR Corrosive Liquid Chemical Level Sensors for level measurement. About 50% of these are Guided Radar level meters, 40% is the tank level sensor.
A wide variety of GWR Corrosive Liquid Chemical Level Sensors options are available to you, such as free samples, paid samples.
Sino-Inst is a globally recognized supplier and manufacturer of Guided Wave radar level measurement instrumentation, located in China.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Guided Wave Radar Level Sensor for Liquid and Bulk Solids Contact level measurement.
Guided wave radar is a measuring instrument based on the principle of time travel. The radar wave runs at the speed of light. The operating time can be converted into level signals by electronic components. The probe emits high-frequency pulses and propagates along the cable or rod probe. When the pulse meets the surface of the material, it is reflected back and received by the receiver in the instrument. And convert the distance signal into level signal. SIRD-701 Guided Wave Radar Level Sensor is suitable for liquid and Bulk Solids measurement, and complex process conditions.
Sino-Inst offers a variety of Guided wave radar Level Sensors for industrial level measurement. If you have any questions, please contact our sales engineers.
Guided wave radar level sensor can be used for continuous measurement of liquids, slurries and granular materials with relatively low dielectric constants. It is suitable for applications where the temperature, pressure changes greatly, and there is inert gas or steam. And has the following characteristics:
1. Strong versatility. Guided wave radar level sensor can continuously measure the level of liquid, solid and powder particles. Choose different probes according to different working conditions. The main probes are divided into three types. They are cable probes, rod probes and coaxial rods. The maximum measurement distance of the cable probe can reach 35 meters. And it has a good measurement effect on the measurement of liquid and solid material levels. Rod probes are mainly used for liquids. Coaxial rod probes are used for liquids and can be used in harsh working conditions such as corrosion and impact.
2. Prevent hanging material. The circuit design and sensor structure of the guided wave radar level gauge make it unaffected during the measurement. It does not require regular maintenance and cleaning to avoid delaying the measurement.
3. Maintenance free. There are no moving parts in the measurement process. integrated design. There is no damage maintenance problem.
4. Strong anti-interference. Guided wave radar level meter uses contact measurement. Strong anti-interference ability. It can also be measured stably under the working conditions containing steam, foam and stirring.
5. Accurate and reliable measurement. The measurement is more accurate. The measurement is not affected by environmental changes. High stability and long service life.
Specifications of Guided Wave Radar Level Sensor
Suitable for Medium: Liquid, solid powder
Application: Liquid and solid powder measure, complicated process conditions
High-frequency microwave pulses from guided wave radar propagate along the detection component (steel cable or steel rod). When encountering the measured medium. Due to a sudden change in the dielectric constant, it causes reflection. A part of the pulse energy is reflected back. The time interval between the transmitted pulse and the reflected pulse is proportional to the distance of the measured medium.
Guided wave radar is a measuring instrument based on the principle of time travel. The radar wave runs at the speed of light. The running time can be converted into a level signal by electronic components. The probe emits high-frequency pulses and propagates along the cable or rod probe. When the pulse meets the surface of the material, it is reflected back and received by the receiver in the instrument, and the distance signal is converted into a level signal.
The reflected pulse signal is transmitted to the electronic circuit part of the instrument along the cable or rod probe. The microprocessor processes this signal. Identifies the echo generated by the microwave pulse on the surface of the material. The correct echo signal identification is done by the pulse software.
The distance D from the surface of the material is proportional to the time travel T of the pulse:
D=C×T/2
Where C is the speed of lightSince the distance E of the empty tank is known, the level L is:
L=E-D
Set by inputting empty tank height E (=zero point), full tank height F (=full scale) and some application parameters. The application parameters will automatically adapt the instrument to the measurement environment. Corresponding to 4-20mA output.
Ultrasonic Level versus Guided Wave Radar Level
Ultrasonic level sensors are non-contact and provide a cost-effective choice for most straight-wall tank applications. Guided wave radar sensors are suitable for liquid and solid applications and operate independently of process conditions.
The ultrasonic liquid level sensor operates by transmitting the sound wave generated by the piezoelectric transducer to the surface of the processing material to be measured. The level sensor measures the length of time it takes for the reflected sound wave to return to the transducer. Successful measurement depends on the reflection of ultrasonic waves from the process material and movement back to the sensor in a straight line. Factors such as dust, heavy steam, water tank obstacles, surface turbulence, foam, and even surface angle will affect the return signal when using an ultrasonic level sensor. It is therefore necessary to consider how the operating conditions affect the sound waves.
Sound waves-Sound must travel through the medium (usually air). This makes the liquid level sensor unsuitable for use in vacuum applications where air molecules do not prevent sound waves from propagating.
Surface Condition-Foam and other debris collected on the surface of the liquid will absorb sound waves and prevent them from returning to the sensor.
Angle of incidence and angle of reflection-Sound waves must be sent and received in a straight line. And the reflective surface must be flat.
Operating temperature-Ultrasonic devices are usually plastic with a maximum operating temperature of 60°C. In addition, varying process temperatures may produce inaccurate level readings.
Working pressure-Ultrasonic equipment is not suitable for extreme pressure limits; the maximum working pressure should not exceed 30 psig.
Environmental conditions-Steam, condensed moisture and other contaminants will change the speed of sound through the air. And greatly affect the accuracy of the returned signal. Therefore, ultrasonic equipment should be installed in a predictable environment.
Guided wave radar (GWR) level measurement
Guided wave radar (GWR) is a method of contact level measurement. It uses a probe to guide high-frequency electromagnetic waves from the level gauge to the measured medium.GWR is based on the principle of Time Domain Reflectometry (TDR). Using TDR, low-energy electromagnetic pulses are guided along the probe. When the pulse reaches the surface of the measured medium, the pulse energy is reflected by the probe to the circuit. The circuit then calculates the liquid level based on the time difference between the transmitted pulse and the received reflected pulse. The sensor can output the analyzed level as a continuous measurement reading through the analog output. Alternatively, the value can be converted into a freely positionable switch output signal.
Unstable process conditions-changes in viscosity, density or acidity will not affect accuracy.
Stirring surface-boiling surfaces, dust, foam and steam will not affect the performance of the device. GWR can also be used with circulating fluids, propeller mixers and aeration tanks.
High temperature and high pressure-GWR performs well at temperatures up to 315°C and can withstand pressures up to 580 psig.
Fine powders and viscous liquids-GWR is used with vacuum tanks containing used cooking oil and tanks filled with paint, latex, animal fat, soybean oil, sawdust, carbon black, titanium tetrachloride, salt and grains.
The radar level sensor is a radar level gauge based on the principle of time domain reflection (TDR). The electromagnetic pulse of the radar liquid level sensor propagates along the steel cable or probe at the speed of light. When encountering the surface of the measured medium, part of the pulse of the radar liquid level sensor is reflected to form an echo and returns to the pulse transmitting device along the same path. The distance between the transmitting device and the surface of the measured medium is proportional to the propagation time of the pulse between them. The liquid level height is calculated.
What is GWR level transmitter?
GWR level transmitter is a guided wave radar level sensor.
How do you calibrate a radar level transmitter?
Three calibration methods: ①Display/debug module (View Point) ② PC debugging software ③HART handheld programmer
Sino-Inst offers over 10 Guided Wave Radar level transmitters for level measurement. About 50% of these are Radar level meters, 40% is the tank level sensor.
A wide variety of Guided Wave radar level meters options are available to you, such as free samples, paid samples.
Sino-Inst is a globally recognized supplier and manufacturer of Guided Wave radar level measurement instrumentation, located in China.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Radar level measurement uses Non-contactingradar technology for Continuous level measurement. Liquids and solids are commonly measured with this measuring technique.
Radar level transmitters use radar technology to perform non-contact continuous level measurement. The radar level indicator converts the level into an electrical signal. The level signal output can then be utilised by other instrumentation to monitor or control. Liquids and solids are commonly measured with this measuring technique. Like: Fly ash silo. Radar level sensors are divided into: Pulsed radar technology and frequency modulated continuous wave (FMCW) radar level sensors.
Application: rivers, lakes, shallows Measuring range: 70 meters Process connection: thread G1½ʺ A / bracket / flange Process temperature: -40～100℃ Process pressure: normal pressure Accuracy: ±10mm Frequency range: 26GHz
Application: rivers, lakes, shallows Measuring range: 30 meters Process connection: thread G1½ʺ A / bracket / flange Process temperature: -40～100℃ Process pressure: normal pressure Accuracy: ±3mm Frequency range: 26GHz
Radar level gauge can measure liquid and solid media. For example: crude oil, slurry, raw coal, pulverized coal, volatile liquids, etc.;
Can be measured in vacuum can measure all media with a dielectric constant> 1.2. Measuring range up to 150m;
The power supply and output signal pass a two-core cable (loop circuit), using 4…20mA output or digital signal output;
Non-contact measurement and installation are convenient and extremely stable materials are used. It is accurate and reliable with a resolution of up to 1mm;
Not affected by noise, steam, dust, vacuum and other working conditions;
Not subject to changes in medium density and temperature. Process pressure can reach 400bar, medium temperature can reach -200℃ to 800℃;
There are various installation methods to choose from: Top installation. Side installation. Bypass pipe installation. And waveguide installation;
Debugging can be selected in many ways: Using programming module debugging , equal to an analytical processing instrument. SOFT software debugging. HART handheld programmer debugging. Debugging is convenient and fast.
Very short microwave pulses with very low energy are transmitted and received through the antenna system. The radar wave runs at the speed of light. The operating time can be converted into level signals by electronic components. A special time extension method can ensure stable and accurate measurement in a very short time.
Electromagnetic waves propagate in the air at the speed of light. The distance between the radar level gauge and the surface of the material can be expressed by the following formula:
D = (1/2)*CT
In the formula:
D ———the distance between the radar level gauge and the surface of the material;
Even in the presence of false reflections, the new micro-processing technology and the unique ECHOFOX- software can accurately analyze the level echo. By inputting the size of the container, the distance value can be converted into a signal proportional to the level. The instrument can be debugged with empty positions.
The non-contact type includes pulse radar and continuous frequency modulation. The probe is usually a horn antenna, that is, a tubular antenna, but the diameter of the horn is different, and the length of the horn is different. So it looks like some speakers, and some look like tubes, but they are actually one.
In addition, the contact radar is equipped with a rod antenna, usually called a guided wave radar, which is a pulse radar in principle. You can also learn more about guided wave radar level sensors.
2. In principle, radar level sensors can be divided into three main types: Pulsed. Frequency modulated continuous wave. And guided wave radar.
Non-contact radar is called a radar level sensor, which includes two types of rod antenna and horn.The contact radar level gauge can also be called a guided wave radar level gauge. Including single rod type and single cable type, double cable type, coaxial type, etc., which includes high-frequency and low-frequency radar level gauge.
Measurement is not affected by temperature, pressure or dust
User-friendly adjustment saves time
Non-contact, continuous level measurement over larger ranges
Unaffected by sludge and biomass, dust, foam, oil, grease and other coatings, uneven surfaces, turbulence, pressure, and vacuum
Single frequency radar level sensors for liquid sensing, dual frequency radar level sensors for level measurement of aggregates, gravel, sand, coal, asphalt, and other solids
Guided wave radar level sensor Principle: The guided wave radar level sensor is a measuring instrument based on the principle of time travel. The radar wave runs at the speed of light. The running time can be converted into a level signal by electronic components. The probe sends out high-frequency pulses and propagates along the cable probe. When the pulse meets the surface of the material, it is reflected back and received by the receiver in the instrument. The distance signal is converted into a level signal.
Different ways of contact: Radar level gauges are non-contact. Guided wave level gauges are contact-type. That is to say, the guided wave type cannot be used in the occasions where food grade requirements are high.
The working medium is different:Guided wave radar level gauges also need to consider the corrosiveness and adhesion of the medium. Moreover, the installation and maintenance of guided wave radars that are too long are more difficult. In the case of low dielectric constant, the measurement principle of radar or guided wave radar is based on the difference in dielectric constant. Since the waves emitted by ordinary radar are divergent, when the dielectric constant is too low, the signal is too weak to measure. Stable. The guided wave radar wave propagates along the probe. The signal is relatively stable. In addition, the general guided wave radar also has a bottom detection function, which can be corrected according to the measured value of the bottom echo signal to make the signal more stable and accurate.
Selection is different: Ordinary radars can be used interchangeably. Guided wave radars cannot be used interchangeably due to the fixed length of the probe (cable) according to the original working conditions. The selection of guided wave radars is more troublesome than ordinary radars.
Different measuring ranges: Ordinary radar is more commonly used on 30 and 40m tanks, and can even measure 150m. Guided wave radar also needs to consider the force of the probe (cable). It is also because of the force that the measurement distance of the guided wave radar is generally not very long. However, the guided wave radar has obvious advantages in some special working conditions, such as stirring in the tank and large medium fluctuations. The measured value of the guided wave radar fixed at the bottom of such working conditions is more stable than that of the flexible radar. There are also small tanks. For level measurement, due to the small installation measurement space (or many interferences in the tank), general radar is not suitable, and the advantages of guided wave radar are revealed at this time.
The measurement dead zone refers to: when the measurement range falls into the blind zone, the deviation between the measured value and the true value does not meet the accuracy requirements set by the level gauge. For example, a 6GHz electromagnetic radar level gauge has a wavelength of several centimeters. At a distance of several wavelengths from the probe, the waveform will reflect interference multiple times, making it difficult to identify the correct reflected wave. The distance of these several wavelengths is the blind zone of the radar level gauge. Some level gauges do not have blind spots, such as capacitance (RF admittance)/static pressure/ray type, etc… It should be noted that blind spots and sensitivity (resolution) are not a concept. Extended reading: Features Of Magnetostrictive Level Transmitters
Check the configuration of the lower range value (0% level, 4 mA) and high range value (100% level, 20 mA). Make sure that the inputted data is as per the datasheet. For example, the lower range value is 10 inch and the high range value is 35 inch (both of it are measured from the bottom of level transmitter probe)
Fill the level transmitter chamber with water up to the 0% level. Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 0% level through HART communicator.
Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on the multimeter) is 4 mA.
Fill the level transmitter chamber with water up to the 100% level. Read the level measurement in the transmitter LCD (or in the HART communicator). Set this condition as 100% level through HART communicator.
Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on the multimeter) is 20 mA.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
