Monthly Archives: January 2022

The Secret of Water Level Control

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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 controller or water level alarm, thereby realizing semi-automation or full automation.

Water level control is generally used for high-level tank water supply and sump drainage. The device that converts the water level signal into an electrical signal to control the start and stop of the water pump is called a water (liquid) level controller. Commonly used water (liquid) level controllers include reed switch water level controllers, float magnetic switch liquid level controllers, electrode type water level controllers, pressure type water level controllers, etc.

RFQ More Level Sensors
Water Level Control

Types of water level controllers

  • Floating ball controller
  • Reed water level controller
  • Cable water level controller
  • Electronic water level controller
  • Capacitive water level controller
  • Tuning fork water level controller
  • Electrode water level controller
  • Photoelectric water level controller

Water has buoyancy, and the float level controller is manufactured according to the buoyancy of the liquid. When the liquid level rises, the float system also rises accordingly. When the liquid level decreases, it also decreases accordingly.

When ascending or descending to the set position, the float system will hit the controller at the set position. This will cause the controller to issue an electrical signal.

The electronic control equipment will act immediately when it receives an electrical signal, cut off or connect the power supply, and constitute an automatic control system.

Extended reading: Float Level Sensors – Single and Multipoint

Reed water level controller is suitable for automatic control or alarm of water level in water towers, water tanks, pools, etc. in industrial and mining enterprises, civil buildings, and scientific and technological research fields. At the same time, it can also be widely used in the “three wastes” disposal facilities for environmental protection.

Extended Reading: 3 inch (3″) Water Flow Meter

There are one or several buoys on the cable water level controller that move with the water level. A permanent magnetic ring is fixed in the buoy. When the buoy moves to the upper or lower water level, the corresponding reed switch will accept the magnetic signal and act to send out the water level electrical signal. . Used to alarm or start the pump to work.

Extended reading: Hydrostatic Level Measurement

The electronic water level controller detects the water level through the built-in electronic probe. Then the chip processes the detected signal. When it is judged that there is water, the chip outputs a high level of 24V or 5V, etc. When it is judged that there is no water, the chip outputs 0V .

The concave-convex level signal is read by PLC or other control circuit boards, and drives the electrical appliances such as water pumps.

It can be installed in any direction. When installed horizontally, it will act when the water level reaches the blue line, and the precision is high. When installed vertically, it will act when the water level reaches the red line, which has a certain anti-wave function.

Extended Reading: Wireless Water Meter

The capacitive water level controller changes according to the small capacitance difference caused by the detection of the water level change. It uses a special ADA capacitance detection chip for signal processing. It can output a variety of signal communication protocols.

Capacitive water level detection can detect the change of water level or liquid in the container through any medium. It avoids the disadvantages of poor stability and reliability of traditional water level detection methods.

The tuning fork on the tuning fork water level controller is excited by the crystal to generate vibration. When the tuning fork is immersed in liquid, the vibration frequency will change. This frequency change is detected by the electronic circuit and outputs a controller quantity.

Extended reading: Magnetic water meter-ultrasonic water meter-mechanical water meter

The electrode type water level controller is an integrated measurement system composed of a primary electrode type sensor and a secondary controller. The water level controller is installed on the top of the container or on the wall of the container, and the electrode is inserted into the liquid.

During measurement, there is an AC signal voltage on the electrodes. When the liquid level rises and touches the electrodes, there is a communication signal current flowing between the electrodes, and then a liquid level signal is generated. After the control board receives the liquid level signal, rectification, filtering, Expansion and other processing. Finally, it is converted into a relay closed contact output or a standard current 16mA output for users to use.

When the liquid level drops and leaves the electrodes, there is no communication signal current flowing between the electrodes. The control board cannot receive the liquid level signal, and the relay returns to the release state or the standard current returns to 8mA.

Therefore, the liquid level can be accurately measured through the contact or non-contact of the liquid and the electrode, the pull-in or non-attraction of the relay or the magnitude of the current.

Read more about: Applications Of Submersible Level Transmitter

The photoelectric water level controller uses infrared detection. It uses the principle of refraction and reflection of light. The light will reflect or refract at the interface of two different media.

When the measured liquid is at a high level, the measured liquid and the photoelectric controller form a kind of interface. When the measured liquid is at a low level, the air and the photoelectric controller constitute another interface. These two interfaces will make the photoelectric control The reflected light intensity received by the light-receiving crystal inside the device is different. That is, it corresponds to two different controller conditions.

Extended Reading: Procurement Guide for Ultrasonic liquid level sensors

Featured Water level Control and Sensors

SI-PCM260 Deep Well Water Level Sensor
SI-PCM261 Submersible Pressure Transducer
SI-151 Hydrostatic Level Sensor
SIRD-908 Radar Water Level Sensor
SI-U03 Float Switch Water Level Controller
SI-U01 Float Level Sensor
ULT-100A Ultrasonic Level Transducer
HS-2000 Ultrasonic Tank Level Sensor-External Mounted
SIRD-701 Guided Wave Radar Level Sensor
Magnetic Level Gauge/Indicator
Differential pressure(DP) level transmitter
SI-U02 Multi-Point Liquid Level Float Switch

Frequently
Asked
Questions

Help Center

A water level controller is a device that manages water levels on a variety of systems such as water tanks, pumps and swimming pools. The basic function of a water level controller is to regulate water flow and optimize system performance.

Extended reading: Radar Water Level Sensor Applied To River/Reservoir Monitoring

The water level controller is an instrument that can help users solve the waste of water resources. It can efficiently and timely solve the water cutoff and overflow conditions. More importantly, it can solve the problem of artificial water level control for users and realize automatic water level control.

The main functions of the water level controller are as follows:

  1. The display mode of the instrument: it has the functions of -1999~9999 measured value display and set value display, and can also display the working status of the light-emitting diode;
  2. Control mode: 1-4 limit control can be selected, LED indication. The control method is relay ON/OFF; with hysteresis (can be freely set by the user), the control accuracy is ±1 word, and the contact capacity: AC220V/3A, DC24V/6A resistive load.
  3. With alarm function: 1-4 limit alarm can be selected, LED indication. The alarm mode is relay ON/OFF; with hysteresis (user can freely set) alarm accuracy ±1 word, contact capacity: AC220V/3A, DC24V/6A resistive load.
  4. It can monitor the change of water level, according to the set upper and lower limit values ​​of water level and water level alarm value, it can automatically control the opening and closing of the water pump, and can output external alarm signals, which is convenient for users to take timely measures to deal with it.
  5. The instrument consists of three parts: sensor, transmitter and receiver. One transmitter can be configured with multiple receivers, and several receivers monitor the water level of the same water tower and pool at different locations. Provide users with more accurate water level information.

The water level controller has the characteristics of compact structure, economy, reliability, practicality, energy saving and consumption reduction. It is a new type of automatic control device worthy of promotion.

Extended reading: Float Switch Water Level Controller

The function of the liquid level sensor is to detect the liquid level. The liquid level sensor is widely used in electrical appliances and industrial equipment that require water level control. The liquid level sensor can realize the function of water shortage protection.

Principle of water level sensor:
The water level sensor has a sensor. Transform the sensed water level signal into a current signal.

There are many types of water level sensors, so their specific measurement principles are different.
If you need to learn more. You can refer to:
Differential pressure type liquid level measuring instrument;
Float level measuring instrument;
Electric liquid level measuring instrument;
Ultrasonic liquid level measuring instrument;
Radar liquid level measuring instruments, etc.

Extended reading: Capacitive water level sensor

Related Blogs

Sino-Inst offers over 20 Water Tank Level Sensors for Water Level Control.

About 50% of these are liquid level meters, 40% is the tank level sensor.

A wide variety of Water Tank Level Sensors options are available to you, such as free samples, paid samples.

Sino-Instrument is a globally recognized supplier and manufacturer of level measurement instrumentation, located in China.

Request a Quote

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A New Choice for Boiler Drum Level Measurement – Guided Wave Radar

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Boiler Drum Level Measurement is very important and necessary in major factories. Drum level is an extremely important control parameter. It is an important guarantee for the production of high-quality steam. It is also directly related to the safe operation of the steam drum.

Excessive liquid level will cause the steam-water separation of the steam drum. Increase the moisture carried by the steam. Deteriorating steam quality. It can cause water to enter the turbine, and even damage its blades in severe cases. If the liquid level is too low, there is less water in the drum. Water vaporizes faster. Causes the downpipe to carry steam. Cause the steam drum to burst or explode.

Therefore, it is important to choose a suitable and safe liquid level sensor to measure Boiler Drum Level.

RFQ More Level Sensor

Why is Boiler Drum Level Measurement important?

In the boiler evaporation equipment, the boiler drum is an important part. The natural circulation loop of the boiler is composed of it, the upper header, the lower header, the lead-out pipe, the descending pipe and the water cooling wall. How the boiler drum level is controlled will affect the following aspects.

When the liquid level of the boiler drum is too high. The space where the steam is located is reduced. This results in increased water carryover in the steam. Causes the steam quality to deteriorate. This is one of them. Second, the water level is too high, and the superheater pipe is easy to accumulate salt scale. The tube is overheated and damaged.

The above two situations will occur when the water level is too high. What happens when the steam drum is full of water?

When the steam drum is full of water, there will be a lot of water in the steam. Severe hydraulic shock to steam lines.

The boiler drum water level is too high or too full. So is it too low?
The answer is of course no.

When the water level in the drum is too low, the water circulation will be disrupted. The water wall will exceed the usual temperature and overheat. If the water level is low to a certain extent, there is a serious water shortage. The device is likely to be severely damaged. even lead to accidents.

From the above content, it can be seen that the high and low water level of the boiler drum will have a certain impact on the safe operation of the boiler. In severe cases, it may even affect the safe operation of the unit. Therefore, it is very important to control the liquid level of the boiler drum. The use of liquid level gauges for liquid level measurement is also an inevitable result.

Liquid level data, seemingly unimportant, is actually very important. So no matter what industry, you must understand your own working conditions when choosing a liquid level sensor. Select the liquid level sensor according to the working conditions, so as to choose the appropriate one.

Extended reading: Hydrostatic Level Measurement

Current Situation of Drum Level Measurement

At present, from the basic principle of drum level measurement. The widely used are mainly based on two principles of connecting pipe type (static pressure) and differential pressure type. Drum level measurement instruments mainly include differential pressure level transmitters, Displacer Level Transmitters and guided wave radar level sensors.

The measurement principle of Differential pressure level transmitters is to measure the liquid level by converting the change of liquid level height into the change of differential pressure. This conversion is achieved by balancing the vessel to form a reference water column. The key to its accurate liquid level measurement is the accurate conversion between liquid level and differential pressure.

Using a differential pressure transmitter to measure boiler drum level must take into account certain physical properties of the fluid. The steam drum contains a two-phase mixture of water and steam under saturated conditions. The density of water and steam varies with saturation temperature or pressure. The density of saturated steam on the water surface, as well as the density of saturated water in the drum, must be considered.

Maybe you can refer to: Rosemount-Boiler Drum Level Transmitter Calibration

More about: Use Differential Pressure Transmitter to Measure Liquid Level

The Displacer Level Transmitter works based on the principle of buoyancy.

When the liquid level is at 0, the torsional moment generated by the torsion tube by the gravity of the float is the largest. The rotation angle of the torsion tube is at 0°.

When the liquid level gradually rises to the highest level, the torsion tube is subjected to buoyancy to generate a torque torque and rotates through an angle. The transmitter converts the angle into a 4~20mA DC signal. The signal is proportional to the measured liquid level.

The density change of the medium in this measurement method will affect the measurement accuracy. Mechanical vibration will also cause inaccurate readings.

The electrical contact level sensors belong to the connected tube type level sensors. The principle is to measure the liquid level by using the characteristics that the electrode in the boiler water has a small impedance to the cylinder and the electrode in the steam has a large impedance to the cylinder.

The conductivity of boiler water in high-pressure boilers is generally tens of thousands to hundreds of thousands of times greater than that of saturated steam. Therefore, the indication value of the electric contact level gauge is less affected by changes in the pressure of the steam drum. It can easily transmit liquid level signals remotely. .

However, the reliability of the sampling sensor is poor, the mechanical seal of the motor is easy to leak, the service life of the electrode is short, the indication is discontinuous, and there is a certain amount of maintenance.

Extended Reading: FMCW Radar for High Temperature Level Sensor

To sum up, due to the complexity of the measurement object of the liquid level in the drum, the uncertain factors in the actual operation and the large measurement error, the measurement of the liquid level sensor in the drum often has a large deviation.

Guided wave radar liquid level measurement is a brand-new measurement technology. It overcomes the shortcomings of liquid level measurement instruments such as differential pressure type, float type, and electrical contact. It is a brand-new liquid level measurement device.

Guided Wave Radar Level Transmitter

Guided wave radar level transmitter uses guided wave radar (GWR) technology. Based on the reflection of microwave on the surface medium. Through the probe, continuous level measurement of liquid and solid levels is completed.

A guided wave radar level transmitter is also called a wave-guided radar level sensor. They can measure both levels and the interface between two media. Through probe rod or cable, complete level contact types continuous level measurement. Such as Coaxial Probe Guided Wave Radar Level Transmitter. This is different from ultrasonic level measurement, which is non-contact measurement. A guided wave radar level transmitter is often used for tank level measurement. Including liquid and solid. Output 4～20mA/HART, so as to measure and control the level during production.

Guided Wave Radar Level Transmitter is a liquid level transmitter based on the principle of time domain reflectometry (TDR).

The electromagnetic pulse 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 Guided Wave Radar Level Transmitter is reflected to form an echo and return to the pulse transmitter along the same path. The transmitter and the measured medium The distance from the surface is proportional to the travel time of the pulse in between. The liquid level height is calculated.

The advantages of the Guided wave radar level transmitter are contact measurement. Signal stability. Measurement unaffected by liquid density and electrical properties. Maintenance free, etc.

However, when the guided wave radar level gauge measures high temperature and high pressure liquids, the measured value will have a large deviation due to the polarization of the air. And the greater the distance between the measurement reference point (flange) and the surface of the measurement medium. The resulting The larger the systematic error.

1) The measurement is accurate.

Density and dielectric constant changes of the medium, as well as fog and foam, have no effect on the measurement. At the same time, the deposition and fouling of the medium on the wave guide have little effect on the liquid level measurement. This is because the signal transmission in the waveguide is not affected by liquid level fluctuations and obstacles in the tank, etc. The feedback signal received by the instrument is correspondingly stronger.

Furthermore, the detected interfering spurious signals in the return signal are extremely small. It is only necessary to detect the transit time of the electromagnetic wave. No signal processing and discrimination is required. Therefore, the measurement of the drum level is accurate.

2) It is convenient to measure and adjust.

Because electromagnetic waves are constant. When programming configuration, only need to input relevant parameters such as measuring range on site. No migration is required to change meter ranges and field calibrations. Greatly improve the efficiency of adjusting the instrument.

More about Advantages of Coaxial Probes

3) Low installation cost and easy maintenance.

Guided wave radar level transmitter consumes less energy. The two-wire transmission method greatly saves the installation cost.

At the same time, the quick universal joint between the probe and the transmitter makes the installation easier. It is more conducive to future maintenance.

Extended reading: Float Level Sensors – Single and Multipoint

Read more about: Condensate Flow Meter-Steam Condensate Flow Meter|Types & Selection Guide

Guided wave radar level transmitter measures drum level

A new type of Guided wave radar level transmitter is used to measure the liquid level of the steam drum of a certain device. The level gauge is certified as a limiting device for high temperature water (HW) and low temperature water (LW) containers. Complies with EN12952-11 and EN12953-9 (TUV certified) standards.

Guided wave radar level transmitter with GPC function technology. Improve the accuracy and reliability of the Guided wave radar level transmitter in high temperature and high pressure environment.

GPC technology

Under high temperature and high pressure conditions, the propagation speed of electromagnetic wave signals in the vapor above the medium (polarized medium) will decrease. At this time, the liquid level value measured by the radar will decrease.

Use guided wave radar with gas phase automatic compensation. Guided wave radar produces a reference reflection within the distance from the flange (measurement reference point), which varies along the rod probe.

Under normal temperature and pressure. The electromagnetic wave has two reflected echoes at the compensation reference end and the liquid level reflecting surface. The measurement is accurate at this time. At this time, the reference distance (the distance from the measurement reference point to the reference rod) is calibrated.

At high pressure, due to the polarization effect of the gas. At this time, the measured distance (the distance from the measurement reference point to the liquid level) has a large deviation from the actual value of the liquid level. if not compensated. Then there will be a large error in the measurement value.

The measured value is compensated by converting the reference reflection.

The calculation formula is: compensation distance = reference distance × (measured distance/measured distance). An accurate actual liquid level value can be obtained.

Application

The steam drum of the boiler plant is the main part of the steam production system.

Use the high temperature heat in the flue gas section of the reformer and the high temperature waste heat of the reformer gas at the furnace outlet. Produce 10.5MPa high pressure steam.

Part of it participates in the reaction as the steam distribution in the process. The other part is sent to the high-pressure steam pipe network to realize the comprehensive utilization of thermal energy and improve the operation efficiency of the device.

Because the traditional measurement can not meet the measurement requirements well. It is necessary to choose other products to replace.

Due to the importance of the steam drum to the boiler plant. To measure the liquid level of the steam drum, three measuring instruments are designed and used: Guided wave radar level transmitter and differential pressure liquid level level transmitter.

Measured by example. At high temperature, the measurement error of ordinary guided wave radar (without GPC) is as high as 18%. With GPC, the measurement error is only 2%.

The measurement data of the GPC guided wave radar level gauge at high temperature is relatively stable and true.

Therefore, it is a perfect combination of guided wave radar technology with GPC and advanced signal processing technology. This makes the guided wave radar level gauge with GPC an ideal solution for level measurement in steam and turbulent boiling conditions.

Extended reading: Vortex Steam Flow Meter

Featured Guided Wave Radar Level Transmitters

SIRD-701 Guided Wave Radar Level Sensor
SIRD-702 GWR Corrosive Liquid Chemical Level Sensor
SIRD-703 GWR Bulk Solids & Powder Solid Level Sensor
SIRD-704 Coaxial Probe Guided Wave Radar Level Transmitter
SIRD-705 GWR Level Sensor for High Temperature & High Pressure

Related Level Measurement Blogs

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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PD Flow Meters Selection and Application | Oil-Liquid

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What is PD flow meter?

PD flow meters (positive displacement flow meters) are the only flow measurement technology that directly measures the volume of fluid passing through the flow meter.
Rotating components within a high precision chamber capture the fluid. The rotational speed of the rotor is proportional to the flow rate. Rotation is caused by the flow of fluid. Mechanical flow meters rely on rotation to drive a magnetic coupling or direct gear train connected to a mechanical counter. Under the conditions of a given flow meter, the volume of this metering space is determined. Just measure the number of rotations of the rotor. The cumulative value of the volume of fluid passing through the flowmeter can then be obtained.

RFQ More Flowmeters

PD Flow Meters can be divided into oval gear flowmeters, scraper flowmeters, dual rotor flowmeters, rotary piston flowmeters, reciprocating piston flowmeters, disc flowmeters, liquid-sealed rotary drum flowmeters, etc.

Features of PD Flow Meters

Advantages

  • High measurement accuracy;
  • The installation pipeline conditions have no influence on the measurement accuracy;
  • Can be used for the measurement of high viscosity liquids;
  • wide range;
  • The direct-reading instrument can directly obtain the accumulation without external energy, and the total amount is clear and easy to operate.

Disadvantages

  • The structure is complex and the volume is huge;
  • The type, caliber, and working state of the medium to be tested are relatively limited;
  • Not suitable for high and low temperature occasions;
  • Most instruments are only suitable for clean single-phase fluids;
  • Generates noise and vibration.

Featured PD Flow Meters

Pointer Type Oval Gear Flow Meter
LCD display Oval Gear High Viscosity Flow Meter
High Temperature Oval Gear Flow Meter – Heating oil
Oval Gear-Marine Fuel Flow Meter
Thermal insulation Oval Gear flow meter
Clamp Filling Oval Gear Positive Displacement Flow Meter
Liquid Roots Meter
Gear flow meter for Micro flow
Helical Gear-PD Flow Meter
Micro Flow Meter

PD Flow Meters are also known as positive displacement flow meters. It is mainly composed of measuring body and measuring part. The metering body consists of a shell and a movable body (rotor of the rotameter). The core part is the movable body, which is the moving part in the measurement process. Each measuring cavity formed by the movable body and the casing is a standard volume unit, which is used to measure the volume of the fluid to be measured.

Extended reading: Fluid flow meter types

The measuring part is actually a rotational speed or counting sensor. Magnetic material is embedded in the pinion extending out of one of the screws on the screw flowmeter. When the screw rotates, the sensor can identify the rotational speed of the screw through the magnetic effect. And convert it into a standard pulse signal or current signal. In this way, the flow can be directly displayed by the secondary instrument or collected and analyzed by the computer.

There are many types of positive displacement flow meters. They can be classified according to different principles. Usually, according to the structure of the measuring element, it is divided into rotor type, scraper type, rotary piston type, reciprocating piston type and diaphragm type.

Among them, the rotor type is the most commonly used. The common gear type, screw type, waist wheel type and egg wheel type flowmeter belong to the rotor type.

Extended reading: Positive Displacement Flow meter Technology

The interior of the positive displacement flowmeter is designed with a space that constitutes a certain volume. The rotor inside the flowmeter rotates under the action of the pressure of the fluid flowing from the inflow port.

With the rotation of the rotor, the fluid flows from the inflow port to the discharge port. At this time, during the rotation of the rotor, a certain volume space is formed between the rotor and the flowmeter housing. The fluid fills this space with the rotation of the rotor. It is continuously sent to the discharge port.

If the volume of the space is designed, the number of rotations of the rotor is measured. The volume given by the space can be obtained, thereby obtaining the volume of fluid flowing through.

Extended reading: Liquid mass flow controller

This fixed-displacement flow measurement method for positive displacement flowmeters can be traced back to the 18th century. It entered the stage of widespread commercial application in the 1930s.

In recent years, the sales of PD flow meters in some industrialized countries have exceeded 20%. In my country, it also accounts for about 20%. It is mainly used in the metering of petroleum-based media.

But because of its precise metering characteristics. In recent years, it has been rapidly expanded to chemical, food, medical and other sectors to accurately measure the total amount and flow of expensive media.

In the measurement of petroleum, an international standard (ISO/DIS 2714) for measurement systems using positive displacement flowmeters has been developed. Moreover, positive displacement flowmeters with high precision, long-term performance retention and high repeatability are also used as standard instruments for industrial flow measurement, calibrating and calibrating industrial instruments.

In short, due to the high accuracy of positive displacement flowmeters, they are often used to measure the flow of relatively expensive media. High viscosity media can be measured. Therefore, it is generally used for the measurement of high-viscosity liquids in petroleum, chemical, metallurgical and other industries.

Extended reading: How to choose a high viscosity flow meter?

Of course it is also suitable for measuring low viscosity liquid media. In addition, positive displacement flowmeters can also measure gases. At the same time, the installation of positive displacement flowmeter does not require the front and rear straight pipe sections.

Extended Reading: Liquid Turbine Flow Meter

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.

Extended Reading: Fuel Flow Meters for Diesel-Marine fuel-Industrial oil

Extended Reading: Mechanical oil flow meter

Positive Displacement Flowmeter Selection

Help Center

The manufacturer generally specifies the flow range according to the type of the measured medium (mainly different viscosity), use characteristics (continuous use or intermittent use) and measurement accuracy.

In order to maintain good performance and long service life of the flowmeter. It is recommended to select 80% of the maximum flow rate of the flow meter when the maximum flow rate is used continuously.

If the manufacturer does not clearly specify the flow range according to the type of medium and the characteristics of use. The maximum flow rate for intermittent use can be 100% of the upper flow limit.

When used continuously, the maximum flow rate of medium viscosity liquid is 80% of the upper flow rate of the flowmeter. The maximum flow rate of low-viscosity and high-viscosity liquids is 50% to 60% of the upper flow rate of the flowmeter.

The fundamental error of most positive displacement flow meters is ±0.5%. The basic error of the higher precision flowmeter is ±(0.1%-0.2%). The oval gear flowmeter can reach ±0.05%. The basic error of the lower precision flowmeter (such as the elastic scraper flowmeter) is ±(1.0%-1.5%).

The accuracy of a positive displacement flowmeter is the fundamental error obtained under laboratory conditions. In actual use, field conditions often deviate from laboratory conditions, resulting in additional errors. The actual error should be the sum of the basic error and the additional error. When selecting and using, measures should be taken according to the on-site situation to ensure the measurement accuracy.

Extended reading: Crude Oil Measurement – Radar Level Meter Measuring Vaulted Buffer Tank

Positive displacement flowmeters rely on the fluid to push the measuring fittings, so the pressure loss is high. The pressure loss of a positive displacement flowmeter is larger than that of other types of flowmeters of the same diameter and flow. The pressure loss of general liquids is 20 to 100 kPa.

When measuring liquids with high vapor pressure, excessive pressure drop will cause cavitation. If cavitation exists for a long time, it will damage the flowmeter accessories. Some flowmeters that allow short-term overflow to 120% of the upper limit of measurement should pay more attention to this problem .

Extended reading: Orifice Plate Flow Meter

Fluid corrosiveness is a major factor in determining flowmeter material.

For various petroleum products, cast steel and cast iron are used.
For slightly corrosive chemical liquids and cold water, it is made of copper alloy.
Made of stainless steel for pure water, high temperature water, crude oil, asphalt, high temperature liquids, chemical liquids, food or food raw materials.

The corrosion resistance of positive displacement flowmeters is generally not strong. In the food and biopharmaceutical industries, due to hygiene requirements, flow meters are frequently sterilized. Fittings that come into contact with fluids must be made of stainless steel and other hygienic materials. They must be easily disassembled.

Generally speaking, the viscosity of various gases is similar. It has no effect on the performance of the flowmeter. The viscosity of liquids is quite different.

In order to adapt to the liquid with high viscosity, the positive displacement flowmeter has a structure with a large gap.

Although the volume-second flowmeter is affected by viscosity, it is less affected than differential pressure and float turbine flowmeters. Viscosity generally affects the measurement error, pressure loss and flow range of positive displacement flowmeters.

Extended reading: Ultrasonic Flow Meters Types & Technical Guide

When the flowmeter is used at higher temperatures, the maximum working pressure rating must be reduced. Sudden valve opening and closing can create water hammer effect. Shock force may exceed operating pressure. Shock force may also cause false readings. Buffer tank may be installed if necessary.

Temperature will not only affect the compressive strength of the flowmeter, but also affect the measurement accuracy. Reduced structural clearance can jam moving parts. Therefore, when used at higher temperatures, a dimensional clearance should be reserved to compensate.

Especially when different materials are used in combination, pay more attention to the difference in thermal expansion coefficient.

Changes in temperature also change the viscosity of the liquid, causing flow changes. It can be corrected by automatic temperature compensation, and there must be a suitable preheating time before use, and observe whether it can operate normally.

Extended reading: Heating Oil Flowmeters

Usually the compressibility of liquids is negligible, however, compressibility should not be neglected when measuring oil with high accuracy.

For example, when the pressure of heavy oil rises from 0.5 MPa to 6 MPa, the volume is compressed by 0.45%. LPG is more compressible.

Gases are highly compressible, and their volume decreases at low pressures in proportion to pressure increases. Most positive displacement flow meters are used for low pressure conditions and can be directly converted.

However, under high pressure conditions, the volume reduction is not proportional to the pressure increase. The gas compressibility factor should be considered.

Extended Reading: Summary Of Crude Oil Flow Measurement Options

Extended Reading: Guide and Selection for Diesel Fuel Flow Meters

Sino-Inst, Manufacuturer for PD Flow Meters. For example: crude oil flowmeter, diesel flowmeter, gasoline flowmeter.

Sino-Inst’s PD 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.

Extended reading: Hydraulic oil flow measurement solutions.

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Tech Guide for Non-Contact Radar Type Level Transmitters

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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 reliable non-contact, maintenance-free continuous measurement of liquids in metal tanks or containers. Not affected by pressure, vacuum or temperature.

Excellent performance under harsh measurement conditions such as flammable, explosive, highly corrosive, high temperature, and viscous. Ideal for corrosive liquids, viscous liquids, slurries, or other applications where direct contact with the medium is not desired. Especially suitable for the measurement of large vertical tanks and spherical tanks. Low dielectric properties allow operation in liquids with a dielectric constant of 2 or greater. It can be used in almost every occasion.

RFQ Level Sensors

Features of Radar Type Level Transmitters

  1. Radar Type Level Transmitter can measure liquid and solid media. For example: crude oil, slurry, raw coal, pulverized coal, volatile liquids, etc.;
  2. Can be measured in vacuum can measure all media with a dielectric constant> 1.2. Measuring range up to 150m;
  3. The power supply and output signal pass a two-core cable (loop circuit), using 4…20mA output or digital signal output;
  4. 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;
  5. Not affected by noise, steam, dust, vacuum and other working conditions;
  6. Not subject to changes in medium density and temperature. Process pressure can reach 400bar, medium temperature can reach -200℃ to 800℃;
  7. There are various installation methods to choose from: Top installation. Side installation. Bypass pipe installation. And waveguide installation;
  8. 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.

Advantages of radar level measurement

  • 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
  • Simple mounting and push-button calibration

Radar Level Transmitters Specifications

– 120GHz

Series
SI-FMF11
SI-FMF12
SI-FMF13
SI-FMF15
SI-FMF21
Applicable medium:LiquidLiquid Liquid Liquid Solid
Measuring range:0.05m~30m0.05m~35m0.1m~100m0.1m~35m0.3m~150m
Antenna:32mm lens antenna42mm lens antenna78mm lens antenna78mm lens antenna78mm lens antenna + purging (or without purging)
Accuracy:±2mm±2mm±2mm (range below 35m)
±5mm (range between 35m-100m)		±2mm±5mm
Medium temperature:-40～80℃-40～110℃-40～110℃-40～200℃-40～110℃
Medium pressure:-0.1～0.3 MPa-0.1～1.6MPa-0.1～0.3MPa-0.1～2.5MPa-0.1～0.3MPa
Signal output:Two-wire system/4…20mA/HART protocol
Four-wire system 4…20mA/ RS485 Modbus		Two-wire system/4…20mA/HART protocol
Four-wire system 4…20mA/ RS485 Modbus		Two-wire system/4…20mA/HART protocol
Four-wire system 4…20mA/ RS485 Modbus		Two-wire system/4…20mA/HART protocol
Four-wire system 4…20mA/ RS485 Modbus		Two-wire system/4…20mA/HART protocol
Four-wire system 4…20mA/ RS485 Modbus
Power supply:Two-wire system/DC24V
Four-wire system/DC12~24V
Four-wire system/AC220V		Two-wire system/DC24V
Four-wire system/DC12~24V
Four-wire system/AC220V		Two-wire system/DC24V
Four-wire system/DC12~24V
Four-wire system/AC220V		Two-wire system/DC24V
Four-wire system/DC12~24V
Four-wire system/AC220V		Two-wire system/DC24V
Four-wire system/DC12~24V
Four-wire system/AC220V
Shell:Aluminum/plastic/stainless steelAluminum/plastic/stainless steelAluminum/plastic/stainless steelAluminum /Plastic /Stainless steelAluminum/plastic/stainless steel
Process connection:G1½A / 1½NPT thread / flange ≥DN50G2A thread/flange≥DN65Flange ≥DN80Flange ≥DN80Flange ≥DN80

– 80 GHz

SeriesLM78x0LM78x1LM78x2
Applicable medium:For normal solid applicationFor liquid applicationFor large range solid application
Measuring range:0.3 m ~ 60m0.08m~30m0.6m ~ 120m
Antenna:Lens antenna/
anti-corrosive antenna /
flange isolated by quartz		 Lens antenna/
anti-corrosive antenna /
flange isolated by quartz 		Lens antenna/
anti-corrosive antenna /
flange isolated by quartz
Accuracy:±1mm±1mm±1mm
Medium temperature:T0:-40~85℃;
T1:-40~200℃;
T2:-40~500℃;
T3:-40~1000℃		 T0:-40~85℃;
T1:-40~200℃;
T2:-40~500℃;
T3:-40~1000℃ 		T0:-40~85℃;
T1:-40~200℃;
T2:-40~500℃;
T3:-40~1000℃
Medium pressure:-0.1~2MPa-0.1~2MPa-0.1~2MPa
Signal output:4 ~ 20mA or RS-4854 ~ 20mA or RS-4854 ~ 20mA or RS-485
Power supply:15~28VDC15~28VDC15~28VDC
Shell:Aluminum alloy, stainless steelAluminum alloy, stainless steelAluminum alloy, stainless steel
Process connection:Thread or flangeThread or flangeThread or flange

– 26 GHz

SeriesSIRD-901 SIRD-902 SIRD-902T SIRD-903 SIRD-904 SIRD-905 SIRD-906 SIRD-908 SIRD-909
Applicable medium:All kinds of corrosive liquidSlightly corrosive liquidCorrosive liquids, vapors, volatile liquidsSolid material, Strong dust
easy to crystallize, condensation occasion		Solid material, Strong dust,
easy to crystallize, condensation occasion		Solid particles, PowderHygienic liquid storage,
Corrosive container		Rivers, Lakes, ShoalRivers, Lakes, Shoal
Measuring range:
10 meters		30 meters20 meters70 meters80 meters30 meters20 meters30 meters70 meters
Antenna:Sealing horn / PTEEHorn Antenna Φ46mm/ Horn Antenna Φ76mm /Horn Antenna Φ96mm / Special CustomInternal tapered rod antenna PVDF / 78mm
Internal tapered rod antenna PFA / 78mm		Horn Antenna Φ76mm / Φ96mm / Φ121mm/Special CustomParabolic antenna Φ196mm /Φ242mmHorn Antenna Φ76mm / Φ96mm / Φ121mm/Special CustomViton / (-40~130) ℃Horn antenna with 76mm/ 96mmHorn antenna with 76mm/ 96mm/ special custom
Accuracy:± 5mm± 3mm±3mm±15mm±15mm±15mm± 3mm± 3mm± 10mm
Medium temperature:-40℃~130℃-40℃~130℃(Standard type)
-40℃~250℃(High-temperature type)		-40℃~130℃(Standard type)
-40℃~250℃(High-temperature type)		-40℃~130℃(Standard type)
-40℃~250℃(High-temperature type)		-40℃~130℃(Standard type)
-40℃~250℃(High-temperature type)		-40℃~130℃(Standard type)
-40℃~250℃(High-temperature type)		-40℃ ~ 130℃-40℃ ~ 100℃40℃ ~ 100℃
Medium pressure:-0.1~0.3 MPa-0.1 ~ 4.0 MPa-0.1~2.0 MPa-0.1~4.0 MPa (Flat flange)
-0.1~0.3MPa (Universal flange)		-0.1 ~ 0.3 MPa-0.1 ~ 4.0 MPa (Flat flange)
-0.1 ~ 0.3 MPa (Universal Flange)		-0.1~4.0 MPaNormal-pressure Normal-pressure
Signal output:4… 20mA /HART （2-wire / 4-wire）
RS485/ Modbus		4… 20mA /HART（2-wire / 4-wire）
RS485/ Modbus		4… 20mA /HART（2-wire / 4-wire）
RS485/ Modbus		4… 20mA /HART （2-wire / 4-wire）
RS485/ Modbus		4… 20mA / HART (2-wire / 4-wire )
RS485/ Modbus		4… 20mA /HART (2-wire / 4-wire )
RS485/ Modbus		4… 20mA/HART (2-wire / 4-wire )
RS485/ Modbus		RS485 / Modbus ( 6~24V DC)
4~20mA / Hart Two-wire ( 24V DC)		RS485 / Modbus ( 6~24V DC)
4~20mA / Hart Two wire ( 24V DC)
Power supply:2-wire（DC24V）/ 4-wire（DC24V /AC220V）2-wire（DC24V）/ 4-wire（DC24V /AC220V）2-wire（DC24V）/ 4-wire（DC24V /AC220V ）2-wire（DC24V）/ 4-wire（DC24V /AC220V）2-wire（DC24V）/ 4-wire（DC24V /AC220V）2-wire（DC24V）/ 4-wire（DC24V /AC220V）2-wire（DC24V）/ 4-wire（DC24V /AC220V）(6 – 24V) DC  / Four-wire
24V DC / Two wire		(6 – 24V) DC  / Four-wire
24V DC / Two wire
Shell:Aluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic /Single chamberAluminum / Plastic / Single chamber
Process connection:Thread, Flange Thread, Flange FlangeUniversal FlangeThread, Universal FlangeThread, FlangeFlange Thread G1½ A″ /Frame /Flange Thread G1½ A″ /Frame /Flange

– 6 GHz

Series
SIRD-801 		SIRD-802SIRD-803SIRD-804 SIRD-805 SIRD-806
Applicable medium:Liquid, slightly corrosive liquidLiquid, especially for corrosive liquidLiquid, especially with pressure and Volatile LiquidSolid particles or block material,
And it is not suitable for solid powder		Liquid, especially suitable for low dielectric constant, sticky, with mixing liquidSolid, especially suitable for high temperature conditions
Measuring range:20m20m35m35m20m15m
Antenna:The Rod Antenna ( PP/PTFE )The Rod Antenna (PTFE)The Horn AntennaThe Horn AntennaThe Horn AntennaThe Horn Antenna
Accuracy:±10mm± 10mm± 10mm± 20mm± 10mm± 20mm
Medium temperature:(-40 ~ 130) ℃-40℃~130℃（Standard type）
-40℃~180℃（High temperature type）		-40℃~130℃（Standard type）
-40℃~250℃（High temperature type）		-40℃~130℃（Standard type）
-40℃~250℃（High temperature type）		-40℃~130℃（Standard type）
-40℃~250℃（High temperature type）		(-40 ~ 400) ℃
Medium pressure:(-0.1 ~ 0.3) MPa(-0.1 ~ 1.6) MPa(-0.1 ~ 4) MPa(-0.1 ~ 0.3) MPa(-0.1 ~ 4) MPa(-0.1 ~ 0.3) MPa
Signal output:(4 ~ 20) mA/HART(4 ~ 20) mA/HART(4 ~ 20) mA/HART(4 ~ 20) mA/HART(4 ~ 20) mA/HART(4 ~ 20) mA/HART
Power supply:Two-wire (DC24V)
Four-wire（DC24V / AC220V）		Two-wire (DC24V)
Four-wire（DC24V/AC220V）		Two-wire (DC24V)
Four-wire（DC24V/AC220V）		Two-wire (DC24V)
Four-wire（DC24V/AC220V）		Two-wire (DC24V)
Four-wire（DC24V/AC220V）		Two-wire (DC24V)
Four-wire（DC24V/AC220V）
Shell: Aluminum /Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steelAluminum / Plastic / Stainless steel
Process connection:Flange (optional) / ThreadWith PTFE plate flangeFlange (optional) / ThreadUniversal joint flangeFlangeFlange

Industrial applications of Radar Type Level Transmitters

Radar level sensors have a very wide range of applications. Almost all media can be measured. This is something other types of meters can only look up to.

It can measure not only spherical tanks and horizontal tanks, but also the liquid level measurement of cylindrical tanks, cylindrical cone tanks, etc.

In terms of tank function, the liquid level in storage tanks, buffer tanks, microwave tubes, and bypass pipes can be measured.

As far as the measured medium is concerned, liquid, particle, slurry, etc. can be measured.

  1. Steel industry

Production processes:
Coal coking: coal preparation bunker, coke bunker, gas tank, coal tar and crude benzene tank
Sintering plant: sintered material mixing bin, cold return ore, pelletizing bin
Ironmaking plant: ironmaking intermediate warehouse, blast furnace material level, etc.

Working characteristics:
Solid material measurement, strong dust, low dielectric constant, long range.
Volatile crystallization of tar and crude benzene;
High temperature and dust adhesion of blast furnace material level;

Selection application:
Solid measurement is mainly based on high-frequency pulse radar level meter.
Guided wave radar level meter can be used for crude benzene and coal tar.

  1. Coal industry

Production link: raw coal bunker, pulverized coal bunker, coal gangue storage level, coal washing pool.
Working condition characteristics: typical solid material measurement, strong dust, low dielectric constant. Long range.
Selection and application: high-frequency pulse radar level meter is mainly used.

  1. Cement industry

Production link: raw material warehouse, raw material homogenization warehouse, clinker warehouse, finished product warehouse, fly ash warehouse, raw coal warehouse, gypsum warehouse, cement slag warehouse
Working condition characteristics: Typical solid material measurement, strong dust, low dielectric constant, long range.
Selection application: High-frequency pulse radar level meter is mainly used.

  1. Power industry thermal power, hydropower, biological power generation

Production processes:
(thermal power) raw coal and pulverized coal silo, circulating water pool, low and high water level, limestone powder silo, ash hopper material level, ash silo, slag silo, desulfurization tower liquid level

Working characteristics:
Solid material measurement, strong dust, low dielectric constant, long range.
Low water level, high temperature and high pressure;
Desulfurization tower liquid level foam, water vapor, crystallization, spray interference, side loading

Selection application:
The measurement of solid materials is mainly based on high-frequency pulse radar level meters.
High and low water level application of guided wave radar;
The low frequency radar level gauge is commonly used in the desulfurization tower liquid level;

  1. Non-ferrous metallurgy industry – aluminum, nickel, zinc, and titanium industries

Production processes:
(Aluminum production) slurry tank, dissolution tank, flash tank, post-dissolution tank, flocculation tank, settling tank, decomposition tank, alumina powder silo.

Working characteristics:
Various chemical reaction environments have high temperature, strong water vapor, stirring or corrosion factors

Selection application:
For the influence of high temperature water vapor, refer to factors such as corrosion, measuring range, stirring, and hanging material;
Choose between guided wave radar or low frequency radar level gauge.
High-frequency radar level gauges are still preferred for solids measurements.

  1. Water conservancy industry

Applications: Hydrological monitoring, flood control alarm, farmland irrigation

Characteristics of working conditions: The signal transmission is far away, the power supply voltage is low, and the installation position is affected by the embankment and dam. The radar wave with small beam angle is preferred.

Selection application: choose high-frequency radar level gauge with MODBUS protocol

  1. Food and pharmaceutical industry

Production processes:
Edible oil tank, soybean meal storage tank

Working characteristics:
Simple tank environment, or with precision requirements, antenna hygiene requirements in the pharmaceutical and food industries

Selection application:
The high-frequency radar level meter is preferred for the measurement environment with high precision;
If there are hygienic requirements, an antenna with a sealed material that meets hygienic conditions should be selected;

  1. Industrial petrochemical, coal chemical

Production processes:
Petrochemical: crude oil depot, gasoline tank, diesel tank, natural gas tank, etc.
Coal coke chemical industry: refer to the coal industry
Calcium carbide chemical industry: coal bunker, calcium carbide bunker, etc.

Working characteristics:
Solid material measurement, strong dust, low dielectric constant, long range.
The measurement environment of various oil depots is simple and may have accuracy requirements
There is pressure in the natural gas spherical tank, and the dielectric constant is small
There is oscillating interference echo in gas tank measurement
Various chemical reactor conditions are different

Selection application:
The measurement of solid materials is mainly based on high-frequency pulse radar level meters.
For various oil depots with precision requirements, high-frequency radar is preferred for spherical tanks;
Gas cabinets that are prone to oscillating interference signals also have limited selection of high-frequency radars;
The chemical reactor is selected according to the actual conditions and parameters;

  1. Environmental protection and water treatment industry

Processing link:
Water collecting well, coarse grid, fine grid, biochemical reaction pool, mud flushing pool, sludge pool, well dissolving medicine pool.

Working characteristics:
Except for ultra-long-range and narrow spaces such as water collection wells, other environments are relatively simple.

Selection application:
The water collecting well can choose guided wave radar or high-frequency radar level gauge according to the range requirements. Generally, ultrasonic level gauges are more commonly used in simple environments.

  1. Semiconductor industry

Production link: silicon micropowder warehouse
Working condition characteristics: very low dielectric constant, strong dust
Selection application: high frequency radar level meter

Radar Type Level Transmitters Applications

  • Liquids with foam, gases (CO2,methane) and other fumes
  • Highly corrosive liquids such as acids and solvents
  • High temperature applications up to 350F such as asphalt
  • Slurries
  • Acids, Caustics and Solvents
  • Vacuum applications
  • Diesel crude oil
  • Sanitary applications
  • Oil-water interface monitoring and detection

Extended reading: Hydrostatic Level Measurement

Ordering Information

When ordering Radar Type Level Transmitters, we need to consider the following factors:

  1. Application medium and measuring range:
    The physical properties of the liquid medium to be measured have a great influence on the measurement range. Liquids are usually divided into four categories: A, B, C, and D.

Class A: non-conductive liquid, the dielectric constant is less than 1.4, which has a great influence on the measurement distance, and the measurement range is
The circumference is small. such as propane.

Class B: non-conductive liquid, the dielectric constant is about 1.9~4, which has a great influence on the measurement distance.
The volume range is medium. Such as gasoline, oil, etc.

Class C: The dielectric constant is about 4~10, which has little influence on the measurement distance and has a large measurement range. like
Concentrated acid, organic solvent vinegar, ethanol, acetone, oil-water mixture, etc.

Class D: conductive liquid, dielectric constant > 10, little influence on the measurement distance, the most measuring range
big. Such as aqueous solution, diluted acid and alkali, etc. ·

When the liquid surface of the tank is smooth. The measurement range of Class A liquid is 5m. For Class B fluids
The volume measurement range is 10m. Class C liquid 15m. Class D liquids can reach 20m. When the liquid level fluctuates, the corresponding measurement range should be appropriately reduced.

  1. Process temperature and process pressure
    Radar Type Level Transmitters are suitable for high temperature and high pressure measurement. However, the temperature and pressure of the tank need to be clearly confirmed.
  2. Antenna style
    The radar level gauge consists of electronic components, waveguide connectors, mounting flanges and antennas.
    The shape of the antenna determines the thin focus and sensitivity. Therefore, the choice of antenna is particularly important.

3.1 Flare Antenna
The horn antenna is suitable for most occasions and has the advantages of good focusing, stable physical and chemical properties, durability and firmness. But it is not suitable for the measurement of corrosive media.

3.2 Rod Antenna
Rod antennas are chemically stable, easy to clean and insensitive to condensation. Suitable for corrosive media.

3.3 Under-the-flange antenna
The flange-mounted antenna is mainly used for the measurement of strong corrosive media.

3.4 Parabolic Antenna
The parabolic antenna has good focusing and is not affected by heating steam, and is especially suitable for in-tank measurement of large containers with heating steam, such as the measurement of residual oil, asphalt, etc., and the measurement range can reach 40m.

3.5 Antenna with stilling pipe or bypass pipe
Install a casing for the antenna. The casing is equivalent to a wire that transmits radar signals. It is suitable for occasions where the surface of the medium fluctuates greatly or the dielectric constant is small.

  1. Display and output signal requirements.
    Our Radar Type Level Transmitters are generally configured with local digital displays. A split display can also be configured if required by the customer.
    Support 4-20mA, 485 and other signal output.
  2. Installation method and installation size.
    Radar Type Level Transmitters support flanged, threaded, bracket mounts. When ordering Radar Type Level Transmitter, customers need to confirm the size with the manufacturer in advance.
  3. Special requirements.
    For example, anti-corrosion, explosion-proof, sanitary and so on.

Extended reading: How to convert a 4-20mA to 0-10V /1-5V signal?

Radar Level Measurement and guide wave radar level measurement Image source: https://instrumentationtools.com/radar-level-measurement/

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; 　　

C ———Speed of light 　　

T ———Pulse time.

Then the liquid level is: 　　L = E-D

In the formula:

L — liquid level; 　　

E ———The total height of the tank; 　　

D ———Air height.

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.

Radar Type Level Transmitters have the advantages of high precision, long life, low maintenance, high performance and so on. Widely used in the industry. Continuous measurement can be performed in harsh environments such as high temperature, high pressure, steam, vacuum and high dust. However, different models of Radar Type Level Transmitters are selected in different environments, and the antennas used are also different.

  1. Rod antenna

Insulated rod antennas are usually made of polymer materials such as polytetrafluoroethylene and polypropylene. Good corrosion resistance. Can be used in strong acid, alkali and other media.

However, the microwave emission angle is relatively large (about 30°), and there are many side lobes. For the case where the structure of the tank is more complicated. There will be more interference echoes. The signal-to-noise ratio is small and the precision is low.

But easy to clean. It is often used to measure tanks and corrosive media with good operating conditions, large diameters, and small measuring ranges.

If the measured medium is volatile and condensed, it is better to choose a rod antenna or a water drop antenna.

  1. Flare antenna

At the same frequency, the larger the diameter of the horn, the smaller the emission angle. If it is a high frequency radar level gauge, the emission angle is smaller and the accuracy is higher.

Most economical radar level gauges use microwave frequencies of 5.8GHz or 6.3GHz. Its emission angle is large, and it is easy to generate interference echoes on the container wall or internal components.

Although the horn antenna increases can reduce the emission angle. But the volume increases and the installation is inconvenient. And the improvement is limited.

Using high-frequency radar, the launch angle can reach 8°. This enables high measurement accuracy even when measuring the level of long and narrow tanks.

If it is used in a large-range measurement site, choose a radar level meter with a large horn antenna. Small horn antennas are suitable for small containers.

If the fluidity of the measured medium is poor and there is a phenomenon of hanging material, then choose a horn or a rod radar level gauge.

  1. Parabolic antenna

This is a new type of antenna that has been introduced recently, and is mostly used in radars that transmit at high frequencies. Because its emission angle is only 7°. Ideal for measuring precise targets and measuring around obstacles.

But its antenna size is large. If the X-band is used, the diameter is up to Φ454mm, and the opening size should be larger than 500mm, which is not very convenient for installation and use.

  1. Plane antenna

The planar antenna adopts planar array technology. That is, a multi-point emission source. Compared with a single-point emission source, it is measured on a plane. rather than a definite point.

With the corresponding electronic circuit, the measurement accuracy of the radar level gauge can reach ±1mm. It can be used for precision metering of storage tanks. Mainly used for metrology-grade radar level gauges. Planar antennas are suitable for a variety of working conditions.

Extended Reading: FMCW Radar for High Temperature Level Sensor

  1. Sleeve antenna

When the dielectric constant is small (1.6~3) or the liquid surface produces continuous eddy current or the device in the container causes false reflection, this type of instrument should be selected.

The casing has a focusing effect on the radar wave, and the antenna is installed in the still-pipe or bypass pipe.

The inner diameter of the casing has an effect on the propagation time of the radar wave. Therefore, when setting the parameters, the parameters of the inner diameter of the casing should be set. Compensation for in-travel time.

In addition, this type of antenna requires that the measured medium has good fluidity and is not easy to hang.

If the container under test has a stirring paddle. And the radius of rotation of the blade is almost equal to the diameter of the tank. Then the echo of the radar level gauge will be seriously disturbed. At this time, the still-pipe radar level gauge is used.

  1. Guided wave radar antenna

Sending and receiving electromagnetic waves through guided metal or cables is a contact measurement.

Because it has little effect on dust, steam, and the adhesion medium on the probe. Therefore, it is more widely used in solid material level and liquid level measurement with small dielectric constant.

The dual-cable guided wave radar level gauge uses the change of measuring capacitance to measure the level of the liquid level. The medium between the two electrodes is the liquid and the gas above it. Suitable for level measurement of corrosive and high pressure media.

Fundamentally solve the influence of temperature, humidity, pressure, material conductivity and other factors on the measurement process. Therefore, it has extremely high anti-interference and reliability.

Coaxial tube radar level gauge is a guided wave radar level gauge equipped with a coaxial tube probe. It is used for liquid level measurement and control of liquids with low dielectric constant or surface fluctuations. Such as If the dielectric constant of the measured material is too low, the general type of radar level meter is not suitable.

Extended Reading: Guided-wave radar (GWR) level transmitter working principle

Most of the time, people don’t think of using radar level sensors as level switches.
The output of radar liquid level sensor is mostly 4-20mA.
However, if the customer’s working conditions require output switching. It can also be customized.
For example, we can add a secondary gauge to the output of the radar level sensor. Convert the current signal into a digital signal.

Extended reading: Float Level Sensors – Single and Multipoint

Radar Type Level Transmitters can be used not only in various tanks. It can also be used in various storage tanks.

Extended Reading: Featured Silo Level Sensors

Different storage tanks have different types of Radar Type Level Transmitters.

A spherical tank, also known as a spherical container, has a spherical shell.
This kind of storage tank is mainly used for the storage and transportation of various gases, liquids and liquefied gases. It is widely used in chemical, metallurgy, petroleum and other industries.

Vaulted tank, also known as vaulted storage tank. It refers to the steel container with the top of the storage tank in the shape of a spherical tank and the tank body in the shape of a cylinder.
This type of storage tank is widely used in the fluid industry, such as the most common type C liquids. In addition, refineries also commonly use vaulted tanks to store diesel fuel, fuel oil, and more.

Floating roof tank, also known as floating roof storage tank. It is divided into inner floating roof tank and outer floating roof tank.

An internal floating roof tank is a floating roof tank with a tank top inside. Its top is a combination of a floating roof and a vault. The inside is a floating roof and the outside is a vault.

The floating roof of an external floating roof tank is a floating roof. It floats on the surface of the liquid storage and floats up and down as the liquid flows in and out. In refineries, these two types of storage tanks are often seen.

Horizontal storage tank. It is mainly composed of tank body, accessories and brackets. It is mainly used in the petrochemical industry for the storage of reaction media, crude oil, petroleum products, etc.

Vertical storage tank. It is mainly composed of foundation, tank bottom, tank wall, tank top and accessories. It is often used as a large oil tank for the petroleum industry. If it is divided by the structure of the tank top, vertical storage tanks can be divided into internal floating roof tanks, external floating roof tanks and vaulted roof tanks.

There are not many types of common measurement tanks for Radar Type Level Transmitters. However, different companies will install some auxiliary equipment inside according to the needs of the work, such as the most common heating coils, agitators, and so on. Therefore, when installing the radar level gauge, not only should pay attention to the shape and size of the storage tank, but also pay special attention to the internal structure.

Extended reading: Industrial Tank level indicators and Tank Level Gauges

More Featured Level Transmitters for Sale

SI-U01 Float Level Sensor
LR series Integral flange Magnetostrictive level sensor
LT series Digital Display Magnetostrictive liquid level sensor
SI-U02 Multi-Point Liquid Level Float Switch
ULT-200A Ultrasonic fuel tank level sensor
Portable Ultrasonic Liquid Level Indicator

HS-ULC-Pro Ultrasonic Non-contact Liquid Level Controller
HS-ULC Ultrasonic Level Switch-External Mounted
HS-2000 Ultrasonic Tank Level Sensor-External Mounted
Differential pressure(DP) level transmitte
Remote Seal Differential Pressure Transmitter
SI-151 Hydrostatic Level Sensor

Read more about: Working Principle Of High Temperature And High Pressure Capacitive Level

Frequently
Asked
Questions

Help Center

We have two kinds of radar level transmitters:

  • Noninvasive or Non-contact Systems
  • Invasive or Contact System

Extended reading: Hydrostatic Level Measurement

The radar transmitter uses a high-frequency oscillator as a microwave generator. The generator produces microwave
shoot down through the antenna. When microwaves encounter obstacles, some of them are reflected back. According to the time difference between the transmitted wave and the reflected wave (ie microwave pulse travel). to calculate the distance to the material surface.

Extended reading: Amazing Solutions for Continuous Liquid Level Measurement

There are 7 main types of level transmitters that Sino-Instrument offers. Each type of transmitter works in a different way, and makes it useful for different types of processes.

For more about: Types of Level Transmitters

Difference 1.
Different measuring ranges Ultrasonic liquid level measuring range: 0-50 meters;
The radar level gauge can measure all media with medium constant >1.2 in vacuum. The measuring range can reach 120 meters.

Difference 2.
The ultrasonic level gauge emits different substances by the sensor (transducer) to emit sound waves. After being reflected by the liquid surface, it is received by the same sensor or ultrasonic receiver.
The radar level gauge emits very short microwave pulses with very low energy, which are transmitted and received through the antenna system. The radar waves travel at the speed of light.

Difference 3.
Ultrasonic level gauges are widely used to measure the height of various liquid and solid materials.
Water and sewage treatment: pump room, water collection well, biochemical reaction tank, sedimentation tank, etc.;
Electric power, mining: mortar pool, coal slurry pool, water treatment, etc.
Radar level gauges can measure liquid and solid media.
For example: crude oil, slurry, raw coal, pulverized coal, volatile liquid, etc.

Read more about: Ultrasonic VS Radar level transmitter-different applications

Extended reading: Ultrasonic liquid level sensors

Extended Reading: Dielectric constant for radar level transmitter

About Non-Contacting Radar, Emerson also has a very comprehensive introduction. You can refer to this.

Sino-Inst offers over 10 Radar level transmitters for level measurement. About 50% of these are Radar level meters, 40% is the tank level sensor.

A wide variety of radar level meters options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of radar level measurement instrumentation, located in China.

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