What is Clamp on Water Flow Meter?

Clamp on Water Flow Meter is also known as the clamp-on ultrasonic flowmeter. Using an ultrasonic flowmeter to measure water flow rate is a great choice.

Clamp on Water Flow Meter measures liquid flow meters with full pipes. Measurable medium: drinking water, river water, sea water, groundwater cooling water, high temperature water, sewage, lubricating oil, diesel oil, fuel oil, chemical liquid and other homogeneous fluids.

Clamp on Water Flow Meter can choose portable host, or wall-mounted host. Non-contact measurement without cutting the line.

Clamp on Water Flow Meter

Why Choose Clamp on Water Flow Meter?

Clamp on Water Flow Meter will be the first choice for many customers to measure water flow. Mainly based on the following points:

  • With a powerful magnet, when measuring steel pipes and cast iron pipes, just attach the sensor to the outer wall of the pipe.
  • Equipped with a grounding terminal, it can be used in situations with strong electromagnetic interference.
  • It can be fixed by steel belt, steel wire rope, tension belt and special fixture.
  • The upper cover of the sensor marks the emission direction of the ultrasonic signal.
  • After the junction box is filled with glue, the protection level can reach IP68.
  • Complete specifications, divided into three types: large, medium and small, measuring pipe diameter range: DN15~DN6000mm, temperature range: -40~90℃.
  • According to different uses, standard clip-on sensors are divided into two categories: portable and fixed.
  • For large diameter pipe measurements, the Clamp on Water Flow Meter is easy to install. And compared to other water flow meters, the cost is reduced.

Technical Parameters of Clamp on Water Flow Meter

Item Performance and Parameter
Convertor Principle transit-time ultrasonic flowmeter

Flow: over 1%-2%(battery-powered supply over ±2% ),Heat: over ±2%,Repeatability: over 0.2%


2×20 character LCD with backlight, support the language of Chinese, English and Italy Convertor dimension:170*180*56cm

Operation Support 16 key light touch keyboard and the Simulation keyboard software
Signal Output

1 way 4~ 20mA output, electric resistance 0~ 1K,accuracy0. 1%

1 way OCT pulse output ( Pulse width 6 ~ 1 0 0 0 ms,default is 2 0 0 ms)

1 way Relay output
Signal Input

3 way 4~ 20mA input, accuracy 0. 1%,acquisition signal such as temperature, press and liquid level

Connect the temperature transducer Pt100, can finish the heat/energy measurement

Data interface

Insulate RS485 serial interface, upgrade the flow meter software by computer, support the MODBUS, METER-BUS etc.

Other Function Automatically remember the previous flow/energy data of 512 days,  128 months and 10 years
Automatically remember the previous flow/energy data of 512 days working condition and check it
Automatically remember the previous 32 times power on/off time and flow rate
Special Cable

Twisted-pair cable, generally, the length under 50 meters; Select the RS485 communication. The transmission distance can over 1000m.

Pipe Installation Condition Pipe Material

Steel, Stainless steel, Cast iron, Copper, Cement pipe, PVC, Aluminum, Glass steel product, liner is allowed.

Pipe Diameter 15mm—6000mm
Straight length pipe

Transducer installation should be satisfied: upstream10D, downstream 5D, 30D from the pump.

Measuring Medium Type of Liquid

Water (hot water, chilled water, city water, sea water, waste water, etc.);  Sewage with small particle content; Oil (crude oil, lubricating oil, diesel oil, fuel oil, etc.);  Chemicals (alcohol, acids, etc.); Plant effluent; Beverage, liquid food;  Ultra-pure liquids; Solvents and other liquids

More about: Sewage Flow Meter Selection


Standard Transducer: -30–90℃; High-temperature transducer: -40–160℃

Turbidity No more than 10000ppm and less bubble
Flow rate 0–±12 m/s
Working Environment Temperature Main Unit: -20–60℃
Flow transducer: -40–160℃; 
Temperature transducer: according to the customer’s demands.

Main Unit: 85% RH; Flow Transducer: Ip67

Power Supply DC  24V or AC  85-264V
Power Consumption 1.5W
Clamp on Water Flow Meter sensors

Working Principle of Ultrasonic Clamp on Water Flow Meter

Clamp on Ultrasonic Flow Meter adopts the measurement principle of time difference method. It uses the ultrasonic wave emitted by the sensor to propagate in the flowing fluid. The sound wave propagation speed in the downstream direction will increase, and the backward direction will decrease. In the same propagation distance, there will be different transmission times. According to the difference between the transmission time and the measured The relationship between fluid velocity measures the fluid velocity.

The flow rate of the fluid is different in different positions in the tube. The flow rate in the center of the tube is faster than the flow rate near the wall of the tube. The flow velocity distribution of the fluid in the pipeline can be represented by the flow velocity cross-sectional distribution diagram.

By setting the flowmeter and considering the cross-sectional distribution of the flow velocity, the average flow velocity can be calculated. Then the volume flow of the fluid can be obtained according to the cross-sectional area of the pipe.

Clamp on Ultrasonic Flow Meter Working Principle

V measure fluid velocity
M ultrasonic reflection times
D pipe diameter
θ The angle between the ultrasonic signal and the fluid
T up The time when the downstream sensor transmits the signal to the upstream
T down Time from upstream sensor to downstream
ΔT = T up – T down

Guess You’ll Like: Ultrasonic flow meters types & technical guide

Recently, our company received a call from a customer asking about an ultrasonic flowmeter for measuring sewage flow.

After communication, it was learned that the customer installed flow meters for many sewage pumping stations. Some on-site installations were pipeline-type electromagnetic flowmeters. Some installed plug-in flowmeters.

The pipeline-type flowmeter was first installed on this site. Later, an insertion-type flowmeter was installed. It was broken and could not be measured normally.

However, the water cannot be stopped at present, and the pipeline-type flowmeter should be reinstalled.

Therefore, the customer came to Sino-Inst and ordered an ultrasonic flowmeter that can be installed on the outer wall of the pipeline to measure the flow. After the construction period allows, it will be replaced with a pipeline-type sewage flowmeter.

In the production of electricity, the amount of demineralized water in power plants is quite large, and how to measure the demineralized water effectively has always been a headache.

According to the traditional flowmeter selection method, orifice flowmeter or turbine flowmeter is generally used.

Some people will ask: Why not use an electromagnetic flowmeter?

Here we need to popularize a common sense about the use of electromagnetic flowmeters. Since the working principle of electromagnetic flowmeters is based on Faraday’s law of electromagnetic induction. When a conductive liquid moves in a magnetic field to cut magnetic lines of force, an induced potential is generated in the conductor. The flow of fluid in .

It is very important to note that the measuring medium must be a conductive liquid. This is the basic requirement for the electromagnetic flowmeter to work properly.

Although the electromagnetic flowmeter has high precision and stable operation, there is no problem in measuring general media, such as sewage, ionized water, acid-base salt and other solutions.

However, because the demineralized water in the power plant has low ion content and low electrical conductivity, its electrical conductivity cannot meet the measurement requirements. Therefore, the electromagnetic flowmeter cannot measure the flow of demineralized water.

Orifice flowmeters and turbine flowmeters are traditional flowmeter types. Because the measuring components need to be in direct contact with the measuring medium. There are also various defects such as blockage, poor accuracy, and troublesome installation. Its effect is also not ideal.

On site visits, we found that there are many disadvantages when using this type of flowmeter.

There are also customers who are consulting our technical department, mentioning that they have used metal rotameters, and there is no problem in measurement. Because it is desalinated by centrifugal pumps, they are often stuck by debris. Also, the pump is frequently started and stopped, and the rotor is often blocked. Broken. Ask if there are more measuring instruments and methods.

In view of this common situation. According to our experience, we recommend that you choose the outer clamp ultrasonic flowmeter, which is very effective to measure the flow rate of demineralized water.

  1. This is the obvious difference between the external clip-on ultrasonic flowmeter and the electromagnetic flowmeter. The external clip-on ultrasonic flowmeter is not affected by the conductivity of the fluid, and can accurately measure pure water with low conductivity or low conductivity that cannot be measured by the electromagnetic flowmeter. other fluids.
  2. The accuracy of the clip-on ultrasonic flowmeter fully meets the measurement requirements, and its accuracy is usually ±1%, and ±0.5% after correction.
  3. Because its measuring probe is outside the pipe wall, it is closely connected with the pipe wall through a couplant, and does not directly contact the measured medium, and there is no blocking part, and its operating life can be very long. Good guarantee. 
  4. Strong anti-interference ability, wide range of power supply, to meet the needs of the scene.
  5. The installation of the outer clamp ultrasonic flowmeter is also very convenient, as long as the outer clamp sensor is installed on the outer pipe to avoid cutting off the pipe and contaminating the demineralized water.

The clamp-on ultrasonic flowmeter is an excellent flow measurement product. Ideal for flow measurement of pipe materials such as PVC, cast steel and stainless steel.

It is not only suitable for measuring low-conductivity demineralized water or pure water that cannot be used by electromagnetic flowmeters and other products. It is also suitable for various other types of fluid media.

The accuracy of ultrasonic flowmeter in measuring liquid flow is almost not affected by the temperature, pressure, viscosity, density and other parameters of the measured fluid.

It solves the flow measurement problems of strong corrosive, non-conductive, radioactive and flammable and explosive media that are difficult to measure by other types of instruments.

For liquids with low dielectric constant, the flowmeter measuring instruments that can be used include electromagnetic flowmeters, turbine flowmeters and other products.

However, in the pharmaceutical, food and other industries, the quality of water is very high. It is often encountered that pure or ultrapure water needs to measure the flow.

What kind of flowmeter is the most suitable for pure water and ultrapure water?

We know that pure water and ultrapure water is a source of high quality water.

The filter cartridges of the ultra-clean filter units for the production of pure and ultra-pure water are made of pure polypropylene. Activated carbon is used to remove inorganic and organic trace contamination of ion exchange resins (nuclear grade) and adsorber resins. Dedicated ion exchange resins (nuclear grade) remove inorganic ions.

Dissolved organic matter is removed by adsorber resin, and the pore size of the sterile filter is 0.2 μm.

The conductivity of pure water and ultrapure water obtained by such purification equipment: 0.055 μS/cm. Bacterial content: 1 CFU/ml. It is generally used in fields with high requirements such as biopharmaceuticals.

Before choosing which flow rate, let’s first compare the application conditions of various flow meters.

  1. Electromagnetic flowmeter. Since the conductivity of pure water is only 0.055 μS/cm. Much lower than 5 μS/cm, so electromagnetic flowmeters can only be ruled out.
  2. Turbine flowmeter. Turbine flowmeters are contact measurements, and pure and ultrapure water are particularly demanding on materials. Therefore, the main material must be 316L during manufacture. Use hygienic clamp fittings. Production costs immediately increased considerably.
  3. Vortex flowmeter, orifice flowmeter, etc. are all contact measurement. will undoubtedly come into direct contact with the fluid. resulting in different levels of pollution. So neither is the best choice.

So, which flowmeter to choose is the most suitable for the ultrapure water device of the pure water system?

There is no doubt that the flow measurement instrument we need has the following points:

  1. The measuring components should not be in direct contact with the measuring medium. Make sure that the liquid to be tested cannot be contaminated in any way.
  2. The measuring instrument must not be affected by the dielectric constant of the measured liquid.
  3. The installation and measurement data of the measuring instrument should not be affected by the size of the measured pipe diameter.

According to the above requirements, Clamp on Water Flow Meter is undoubtedly the best representative for measuring such liquids.

Clamp on Water Flow Meter is a non-contact meter, which can measure the flow of medium with large diameter and can also be used for the measurement of medium that is difficult to touch and observe.

So far, we believe that the Clamp on Water Flow Meter is the best choice for measuring the flow of ultrapure water system purified water equipment.

Recently, a customer called and said that he wanted to measure the flow output of circulating water. The diameter of the pipe is also not sure what it is. Very vague consultation. Said to use a Doppler flowmeter.

Our technical engineer said if the measurement is circulating cooling water. Cannot be measured with a Doppler flowmeter. It is only used in rivers and channels. Doppler measurement principle: double-beam acoustic Doppler profile flow measurement technology to measure.

At present, it is recommended that he use an external clamp-type flowmeter, and the principle of measurement is the time difference method.

Technical parameters of dual-beam acoustic Doppler profile flow measurement technology:

  1. Measurement principle: dual-beam acoustic Doppler profile current measurement technology;
  2. Flow velocity measurement range: ±0.01m/s—±5m/s, maximum ±20m/s;
  3. Flow velocity measurement accuracy: ±1%, ±5mm/s;
  4. Maximum profile distance: 120m;
  5. Transducer wave velocity angle: 1.5°±0.2°;
  6. The maximum number of layers in the unit: 128 layers, and the flow velocity of the layered profile can be displayed;
  7. Layer thickness range: 0.5-4m;
  8. Water level measurement range: 0.1-20m;
  9. Water level measurement accuracy: 0.5%, ±5mm;
  10. Communication interface: RS232, RS422, MODBUS interface;
  11. The instrument directly outputs data: average flow rate, water level, real-time flow, cumulative flow; the instrument directly outputs data without any external transfer calculation module to prevent tampering with the original data.
  12. Alarm output function: can output low water level alarm, instrument tilt alarm function;
  13. Built-in storage: It can store the flow rate data for more than one year, and has the function of re-issuing data over time to meet the needs of the central platform to retrieve flow data in real time.
  14. Protection level: IPX8 and IP6X are required

After comparison, the customer found that the principle of the time difference method of using the clamp-on flowmeter was indeed suitable for him. He said he was very satisfied with the advice we gave.

We are a professional technical manufacturer of ultrasonic flowmeters, if you need it, welcome to consult!

The clamp-on ultrasonic flowmeter does not need to disconnect the pipeline and stop production during installation, which brings great convenience to the majority of users and is deeply loved by the majority of users.

But in general, it is only suitable for pipes of a single material. Such as carbon steel pipes, stainless steel pipes, PVC pipes. Measurements are not possible on lined pipes or pipes with cladding material.

However, some special pipelines can also be treated with methods to facilitate the use of clamp-on ultrasonic flowmeters.

A customer wants to measure the flow of tap water. But the pipes are galvanized pipes. Our technical engineers give the following solutions:

  1. Connect the instrument cable first. Input the pipeline parameters after power-on, and calculate the installation distance of the probe;
  2. Use a polisher to polish off the galvanized layer of the probe installation point on the pipeline. Until the carbon steel layer inside the pipe is exposed;
  3. Apply the fine mixture and bind the upstream and downstream probes according to the conventional method;
  4. Check the working status of the instrument until it works normally.

In this way, Clamp on Water Flow Meter can work well.

Strap on flow meter X3 is very unique in its structural design. It uses circular magnetic steel to realize automatic engagement during installation. It only takes 2-3 minutes to complete from installation to measurement. It also uses the current popular OLED display, It can be easily read even in insufficient environments.

Strap on flow meter X3 is widely used in flow measurement and monitoring in the production process. The application of the product continuously effectively and accurately controls the flow of the fluid, while improving the yield of the product. It even saves the investment of personnel and brings benefits to the production enterprise.

Strap on flow meter X3 can meet the needs of different pipe materials: stainless steel pipe, carbon steel pipe, copper pipe, plastic pipe (PVC, PPR, PPH, HDPE), etc.

Strap on flow meter X3 almost meets the measurement of different clean fluids: various acids, alcohols, chemical solvents, alcohol, drinking water, Coca-Cola water… etc.

MoeldX3-φ6.35X3-φ9.53 X3-φ12.7X3-φ15X3-φ20X3-φ25

More Water Flow Meter Types

Water flow meters are flow meters that can diaplay the flow rate of industrial water pipe.

A water flow meter measures the amount of water flowing through a pipe. We have several kinds to choose from, depending on the application, maintenance needs, and budget.

Extended reading: 2 inch Water Flow Meter

There are 4 common water flow meter types:

Turbine (also called mechanical), Vortex, Ultrasonic, and Magnetic. We will tell you everything you need to know about them and help you choose one for your application.

Read more about: Types of Water Flow Meter


Our clamp-on flow meters’ accuracy is generally 1%. This accuracy has been able to meet most of the measurement needs.

The clamp-on flow meter is a flow meter with an external clamp-on flow sensor. Most flow meters are in-line pipe section mounts. The Clamp-on flow meter is a flow meter that only needs to be clamped on the outside of the pipe to measure the flow rate. This is important for many pipes that cannot be cut and bored.

Clamp-on flow sensors are based on the time difference method. The time difference caused by different propagation velocities during forward and reverse propagation is used to calculate the velocity of the measured fluid.

Clamp-on flow sensors employ two acoustic transmitters (sa and sb) and two acoustic receivers (ra and rb). Two sets of sound waves from the same sound source are transmitted between sa and ra and between sb and rb respectively.

The clamp-on ultrasonic flowmeter is installed along the pipeline at an angle of θ (generally θ=45°).

Due to the sound waves traveling downstream are accelerated by the fluid. The sound waves traveling upstream are delayed. The time difference between the clamp-on ultrasonic flowmeters is proportional to the flow rate.

You can also send a sinusoidal signal to measure the phase shift between two sets of sound waves or send a frequency signal to measure the frequency difference to measure the flow rate.

If the water meter is divided into two categories. You may be referring to velocity water meters and volumetric water meters.

In fact, water meters can be divided into 8 types according to measurement principle, measurement grade, nominal diameter, use, installation direction, temperature, pressure and form.

  1. According to the measurement principle: speed water meter, volumetric water meter.
  2. According to the measurement level: A-level meter, B-level meter, C-level meter, D-level meter. The larger the range, the higher the measurement level.
  3. According to the nominal diameter: large diameter water meter, small diameter water meter.
  4. According to the purpose: civil water meter, industrial water meter.
  5. According to the installation direction: horizontal installation of water meters, vertical installation of water meters.
  6. According to the temperature: cold water meter, hot water meter.
  7. According to the pressure: ordinary water meter, high pressure water meter.
  8. Classification by form: analog type, digital type, analog-digital combined type.

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Sino-Inst, Manufacturer for Clamp on Water Flow Meters. It can measure a single sound-conducting liquid medium of DN 15—6000mm. It can measure even liquids such as water, sea water, oil, and slurry.

Sino-Inst’s Clamp on Water 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.

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