The Portable Doppler Flow Meter uses the Doppler effect of sound waves propagating in the fluid. Hand-held design, suitable for handheld wading water flow measurement.

The Portable Doppler Flow Meter (Model: LSX-2) can obtain the velocity of the fluid by measuring the Doppler frequency shift of the sound waves scattered by the moving particles in the fluid. Combined with the built-in pressure water level gauge, the velocity area method can be used to measure the flow of the liquid. It is suitable for flow measurement of open channels, rivers, pipelines and difficult-to-build standard sections. It can work continuously for more than 12 hours on a single charge.

Features of Portable Doppler Flow Meter

• The flow rate range can reach 0.02-5m/s, and the resolution is 1mm/s.
• High response time. It takes a long time to get the flow rate and the measurement results are refreshed in real time.
• Flow measurement by velocity area method, suitable for full and non-full pipes. The water level relationship of the section can be set freely.
• The integrated pressure and water level sensor can directly measure the water depth and can be used in shallow water.
• Fluid mechanics shell design. Little impact on the flow state of the water body. Does not affect the measurement accuracy.
• Small and lightweight handheld terminal with a graphic display interface. It can display the flow rate, flow, water level, and water temperature in real time.
• 16MB internal storage space. It can store more than 100,000 data.
• Equipped with data receiving software. Used for data export and processing.
• Built-in multiple standard flow rate measurement methods and flow calculation methods.
• Rechargeable battery pack, continuous use for more than 12 hours.

Specifications of Portable Doppler Flow Meter

Extended reading: Make Ultrasonic Open Channel Flow Meter Work for You

Portable Doppler Flow Meter to measure open channel flow

Portable Doppler ultrasonic open channel flowmeter uses the principle of Doppler velocity area method to monitor flow. It is designed for flow velocity and flow measurement in open channels and partially filled pipes.

The principle of the Portable Doppler Flow Meter is to measure the fluid flow rate using the ultrasonic Doppler principle.

The liquid level is measured by pressure and ultrasonic sensors. The calculator can set multiple point coordinates to simulate the shape of the weir trough to obtain the cross-sectional area, so as to measure and monitor the flow.

The principle of ultrasonic Doppler is adopted, that is, any liquid flowing in the pipeline has discontinuous disturbance.

These discontinuous disturbances can be suspended solid particles or bubbles, or interfaces caused by fluid disturbances.

This disturbance causes the reflected ultrasonic wave to produce a Doppler frequency shift Δf. The Doppler shift Δf is a linear function of the flow velocity. By measuring the Doppler frequency shift Δf, and according to the propagation speed of sound waves in the water. The flow velocity of the disturbance can be calculated, and then the water flow velocity can be obtained.

Only need to connect the flowmeter probe and the handheld controller when using the equipment.

Use the measuring rod to fix the flowmeter probe.

Put the flowmeter probe into the channel or water body to be measured.

The hand-held controller can display the corresponding flow rate information.

How much is a 2 inch water flow meter? Let’s find out.

Portable transit time flow meter

Handheld Ultrasonic Flow Meter ( Model:2000H) has been successfully applied to measurement work in various industries. The measuring range is 20-6000mm (0.5-20 inches). A non-contact measurement method is adopted. Flexible operation and easy to carry. Conductive or non-conductive, corrosive or non-corrosive liquids can be measured. Various fluids: water, pure water, sewage, sea water, chemical fluids, river water, fuel Oil etc. can be measured.

Sino-Inst, Manufacuturer for Portable Doppler Flow Meters. It can measure a single sound-conducting liquid medium. It can measure even liquids such as water, sea water, oil, and slurry.

Sino-Inst’s Portable Doppler Flow Meter, 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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KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.

Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.

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What is a Doppler flow meter? Doppler Flow Meter is a flow meter that uses the doppler effect principle to monitor the liquid flow rate.

Doppler Flow meter use reflected ultrasonic sound to measure the fluid velocity. By measuring the Doppler frequency shift of the sound waves scattered by the moving particles in the fluid, the velocity of the fluid can be obtained. Combined with the built-in pressure water level gauge. Using the velocity area method. The flow of liquid can be measured. Suitable for flow measurement in open channels, rivers, and various full and partial open channels.

Features of Doppler Flow Meter

• All functions in one design. Simultaneous measurement of average flow rate, water depth, and water temperature
• The velocity area method is used to measure the flow, and there is no head loss. There is no need to build a standard weir.
• The ultrasonic Doppler principle is used to measure the flow velocity. The measurement accuracy is high and the initial speed is low.
• No mechanical rotor structure. It has no effect on the water flow state, and the measurement is more accurate.
• Comes with a temperature sensor. It can be used to compensate for the effect of water temperature on the speed of sound.
• It can measure instantaneous flow and cumulative flow.
• Using frequency domain Doppler analysis algorithm. The data is stable and reliable, and the real-time performance is strong.
• Simple installation. No need for auxiliary engineering facilities

Specifications of Doppler Flow Meter

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Doppler flow meter working principle

For flow velocity measurement, the first thing to explain is the Doppler shift. When there is relative motion between the wave source and the observer, the frequency received by the observer is different from the true frequency of the wave source. The difference between the frequency of the received signal and the frequency of the sound source is called the Doppler shift. Its size is determined by the relative speed between the two. This physical phenomenon is called the Doppler effect.

When measuring the flow velocity, the wave emitted by the probe encounters suspended matter, solid particles, vapor bubbles, and even unstable vortices and disturbances in the medium that follow the wave. Both will produce reflected waves that deviate from the transmit frequency, resulting in Doppler frequency changes. This effect is proportional to the velocity of movement of the reflector.

The receiving probe receives the reflected wave from each point. After complex signal processing, dynamic spectrum analysis and accuracy calculation. The flow velocity of the fluid in the pipe section can be obtained.

Flow rate calculation

The ultrasonic beam emitted from the Doppler velocity sensor (transducer) encounters particles or bubbles moving in the fluid. It is reflected back and received by the Doppler flow sensor (transducer). The Doppler frequency shift of the transmitted signal and the received signal is proportional to the fluid velocity.

Among them:
u is the channel flow rate,
f1 is the working frequency of the sensor,
δfd is the Doppler frequency difference.

Flow calculation

Real-time flow velocity and water level data collected by acoustic Doppler flowmeter.
The data acquisition and processing unit receives the flow rate and water level data. Calculate the instantaneous flow rate and record it as Qs;
Then calculate the accumulated flow rate and record it as Q; its flow rate can be calculated as follows:

Qs=AV

In the formula, A is the water area of the pipeline, and V is the average flow velocity of the section.

Q = QsT

In the formula, the instantaneous flow of Qs section, T is the accumulated time (unit h).

Read more about: Ultrasonic flow meters types & technical guide

Ultrasonic doppler flow meter advantages and disadvantages

Ultrasonic doppler flow meter advantages and disadvantages

Advantages of ultrasonic Doppler flowmeter:

1. Contact measurement. Can accurately measure the flow rate of the fluid;
2. Wide range of use. It can measure the flow velocity of rivers, channels, dissatisfied pipelines, and urban underground pipe network sewer scenarios;
3. Simple installation. No baffle or weir groove is needed. The data can be measured by simply contacting the sensor directly with the fluid;
4. Low power consumption, diversified power supply methods, 6v power supply. Optional external power supply, battery power supply, solar power supply;

Disadvantages of ultrasonic Doppler flowmeter:

1. Cannot measure pressured pipelines, closed pipelines and high temperature environments;
2. The water depth is less than 10cm and cannot be measured;
3. The stable data can only be measured in a place where the water flow is stable, and there are certain requirements for the selection of the installation location;
4. For a site with a large turbidity, it is not as good as a site with more floating objects, garbage, and bottom silt, and accurate data cannot be measured;

Ultrasonic Doppler Flow Meter Applications

Ultrasonic Doppler Flow Meter Applications

Fixed Doppler ultrasonic flowmeters

Mainly used in environmental testing of urban sewage treatment plants, drainage pumping stations, and mining, oilfields, metallurgy, chemical, oil refining, paper, food and other industries.

Flow measurement of urban drainage, industrial wastewater, domestic sewage, mud, paper pulp, oil-water mixture, etc.

It is suitable for hard pipes such as steel and hard plastic pipes.

It can measure two-phase liquids containing suspended solid particles or bubbles in tubes with various tube diameters and wall thicknesses.

Doppler flow meter open channel

Doppler flow meter open channel

There are many monitoring methods for measuring the flow of water in open channels, among which the water level flow method and the velocity area method are the majority. The former uses an ultrasonic open channel flowmeter to measure, and the latter uses a Doppler flowmeter to measure in an open channel.

The methods used for different open channels are different. Here we mainly talk about what conditions the Doppler flowmeter must meet for measurement in an open channel.

The Doppler flowmeter is in full contact with the water through the flow rate sensor. The real-time flow rate is measured. Input the width, shape, and water depth of the open channel to the host. The host uses the speed area method to convert the real-time flow.

Therefore, it requires the water depth to immerse the sensor in order to obtain more accurate data.

Due to the principle of ultrasonic measurement, it is determined that the Doppler flowmeter measurement in the open channel needs to meet the following conditions:

1. The flow rate of the water flow should be uniform, and there should be no plain flow (to ensure such measurement conditions, the site should meet the straight channel with 15 times the channel width)
2. Water depth requirement: no sensor (Yuzheng Doppler flowmeter requires water depth ≥13cm)
3. Width of open channel ≥50cm
4. The water flow velocity is required to be 0.04m/s-10.00m/s. If the flow velocity is too fast, the measurement will be inaccurate
5. There should be no rubbish and large floating objects in the open channel
6. The water in the open channel should not be too pure, for example, pure water cannot be measured

The above six points are the conditions that need to be met simultaneously for the measurement in the open channel of the Doppler flowmeter. Of course, before the measurement, the selection of installation and the selection of the installation point are also very important.

If you still don’t understand the details, you can contact Sino-inst technical consultant to get in touch to solve your troubles in detail.

Extended reading: Make Ultrasonic Open Channel Flow Meter Work for You

Application of Ultrasonic Doppler Flowmeter in Irrigation District

Application of Ultrasonic Doppler Flowmeter in Irrigation District

1.Check the water level and velocity curve

Portable Doppler ultrasound can be used to place it in the channel of the irrigation area. During the upstream discharge process, the water level, velocity, and flow changes are measured. The water level, velocity, and flow meter are generated.

In the later calculation, you can directly use the ultrasonic water level gauge or the radar water level gauge for online monitoring. Combine the existing water level, velocity and flow relationship to get the flow value under the current water level.

When the upstream and downstream channels of the irrigation area are changed, re-measurement is required. This method is suitable for use in irrigation areas that require cost and require mass monitoring.

2.Long-term online monitoring

Use LSX-1 Doppler ultrasonic flowmeter with telemetering terminal. Use city power or solar power system for power supply. Fix the flowmeter in the channel. The telemetry terminal periodically collects the data in the flowmeter and sends it to the server remotely via GPRS. The data can be viewed through the WEB platform.

Portable Doppler Flow Meter

The Portable Doppler Flow Meter uses the Doppler effect of sound waves propagating in the fluid. Hand-held design, suitable for handheld wading water flow measurement.

The Portable Doppler Flow Meter (Model: LSX-2) can obtain the velocity of the fluid by measuring the Doppler frequency shift of the sound waves scattered by the moving particles in the fluid. Combined with the built-in pressure water level gauge, the velocity area method can be used to measure the flow of the liquid. It is suitable for flow measurement of open channels, rivers, pipelines and difficult-to-build standard sections. It can work continuously for more than 12 hours on a single charge.

Transit time vs Doppler flow meter

There are two types of ultrasonic flowmeters, one is the time difference measurement method, and the other is the Doppler method. Many users often only know one of them.

Here, we make a simple comparison so that you can choose the correct model.

1.The measurement principle is different.

The main principle of the time difference method is that when the ultrasonic beam propagates in the liquid, the flow of the liquid will cause a small change in the propagation time. The change in its propagation time is proportional to the flow rate of the liquid.

At zero flow, the time required for the two sensors to transmit and receive sound waves is exactly the same. The only technology that can actually measure zero flow.

When the liquid is flowing, the transmission time of sound waves in the counter-current direction is longer than that in the downstream direction. The Doppler method uses the characteristic that the ultrasonic wave will be scattered when encountering tiny solid particles or bubbles in the propagation path.

2.The applicable medium is different.

The time difference ultrasonic flowmeter can only measure clean liquids. It will not work well when it contains more solid particles or bubbles.

The Doppler method uses the scattering characteristics of ultrasonic waves for measurement. Therefore, the Doppler method is suitable for measuring fluids containing solid particles or bubbles, but clean liquids cannot be measured.

3.The measurement accuracy is different.

The time difference method has higher measurement accuracy, and the Doppler method has lower measurement accuracy.

Since scattered particles or bubbles exist randomly, the sound transmission performance of the fluid is also different. If it is a fluid with poor sound transmission performance, the scattering is stronger in the low velocity area near the pipe wall.

However, the scattering of fluids with good sound transmission performance is dominant in the high velocity area, which makes the measurement accuracy of the Doppler method lower.

Although it adopts a structure in which the transmitting transducer and the receiving transducer are separated. In this way, only the scattering in the middle area of ​​the velocity profile can be received. However, the measurement accuracy is still lower compared with the time difference method.

4.The working conditions are different.

The time difference method is suitable for full pipe measurement.
The Doppler method is suitable for measuring the flow of full pipes, partial pipes, open channels, etc.

OMEGA Engineering has a good explanation of Doppler vs Transit Time. Let’s look together.

Video source: https://www.youtube.com/watch?v=NQWNYARWmB8

More Featured Ultrasonic Flowmeters

Sino-Inst, Manufacuturer for Ultrasonic Doppler Flow Meters. It can measure a single sound-conducting liquid medium. It can measure even liquids such as water, sea water, oil, and slurry.

Sino-Inst’s Ultrasonic Doppler Flow Meter, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, US, and other countries.

KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.

Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.

drurylandetheatre.com

Ultrasonic open channel flow meter can measure the water level, flow rate, and total volume flowing through weirs, troughs, channels, and partially filled pipes. Ultrasonic open channel flow meter is used in conjunction with Parshall flume. Using hydraulic flow measurement, ultrasonic positioning, microcomputer processing, digital display, and other technologies. It can be installed and automatically measured in harsh environments. Commonly used for agricultural irrigation water discharge measurement, wastewater, sewage, and other measurements.

Parshall Flume (PVC material, stainless steel material) for Open Channel Flow Meter

When choosing the type of weir and trough for measuring water, it is necessary to consider the size of the flow in the channel, the flow pattern of the water in the channel, and whether it can form a free flow. According to the different large flow, we can choose different weir grooves.

• The large flow rate is less than 40 liters/sec. It is recommended to use a right-angled triangular weir;
• It is recommended to use Parshall tank for more than 40 liters/sec;
• The upstream channel is short, and the large flow rate is greater than 40 liters/sec. It is recommended to use a rectangular weir.

Conditions permit, a good choice of Parshall slot. The water level-flow relationship of the Parshall trough is calibrated by the laboratory, and the requirements for the upstream flow into the trough are relatively weak. The water level-flow relationship of the triangular weir and the rectangular weir is derived from theoretical calculations, and it is easy to cause additional errors due to ignoring some use conditions.

Use glass fiber reinforced plastic to make the measuring weir or trough. The size of the mouth of the triangular weir and the rectangular weir should be accurate, and the surface facing the water inlet should be smooth; the size of the throat part of the Parshall groove should be accurate, and the inner surface of the groove should be smooth.

Common installation methods and installation precautions of Parshall groove:

• Put the Parshall trough into the open channel. Keep the trough level. The centerline of the Parshall trough should coincide with the centerline of the channel, so that the water flow into the Parshall trough does not appear drift.
• After the Parshall trough is filled with water, the flow state of the water should flow freely. The submergence degree of the Parshall trough is less than the specified critical submergence degree.

Require:
Keep the downstream discharge of the Parshall trough unblocked. Do not accumulate water, if not unblocked. Keep the water level difference greater than or equal to 30MM.

The straight section before the Parshall trough has a distance buffer of 1 to 3 meters. The buffer channel should be level with the bottom of the trough. It is convenient for ultrasonic measurement.

It must be ensured that there is a water level difference downstream of the Parshall trough. The discharge is unobstructed and no water will accumulate.

Extended reading: Dam water level measurement

Open Channel Ultrasonic Flow Meter Working Principle

The open channel flowmeter is based on the specific shape of the Parshall metering groove/weir plate metering groove. It guarantees a certain liquid level and knows a certain flow rate. The Parshall groove/weir plate metering groove is selected as the specific flow channel. The measurement accuracy is high. Easy to install.

The sensor measures the height of the liquid level, which is processed by 89C52 series single-chip microcomputers to obtain the instantaneous flow and cumulative flow values.

The flow can be expressed by the following formula:
　　Q=KHn
　　Q: Instantaneous flow rate (t/h) K: Flow rate constant
　　H: height of liquid level n: nth power value

The instantaneous flow is processed by the cumulative accumulation to obtain the cumulative flow.

Extended reading: Radar Non Contact Water Level Sensor

Inline Ultrasonic Flow Meter

Transit Time Ultrasonic Flow Meter Working Principle

Transit Time Ultrasonic Flow Meter adopts the measurement principle of the 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.

Notes:
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 the upstream sensor to downstream
ΔT = T up – T down

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

Ultrasonic Doppler Flow Meter Working Principle

Ultrasonic Doppler Flow Meter uses the physical principle of Doppler frequency shift to measure the water flow velocity.

Doppler effect (Doppler frequency shift) principle:
The sound waves emitted by one object are received and reflected by another object. If the object emitting the sound wave is moving relative to the receiving object. The frequency of the sound wave received by the receiving object will be different from the frequency of the emitted sound wave.

If the relative distance between two objects is reduced, the received frequency will increase.
If the relative distance between two objects is increased, the received frequency will decrease.

Such Doppler effects often occur in daily life. For example: when you hear the sirens (sounds) of an oncoming police car. The sound will appear higher in frequency. When the police car is far away from you, the sound it hears will become lower.

Through the difference between the frequency of transmitting ultrasonic waves and the frequency of receiving ultrasonic waves, the specific flow rate can be calculated. Then the water level is measured by the pressure sensor, and the water passing area is calculated from the water level and channel size.
Finally, the velocity and area are integrated to calculate the final instantaneous flow.

Calculation formula:
Velocity × water area × 3600 seconds = instantaneous flow rate (cubic meters/hour)

Read mroe about: Irrigation Flow Meters for Agriculture Water System

Ultrasonic Open Channel Flow Meter Measures Sewage

Because the ultrasonic open channel flow meter uses open channel non-contact measurement. Therefore, the probe can be separated from the host. It can effectively solve the problems of probe corrosion and instrument accuracy, so it is widely used in irrigation and drainage and sewage measurement.

Read more about: Common River Water Level Measurement Methods

Note when installing:

• To ensure that the sewage flowing through the flow tank has no foreign matter. A filter must be installed not far upstream of the flow tank;
• To ensure that the sewage flowing through the flow tank is stable and without ripples. A still water well connected to the flow trough can be arranged on the side of the flow trough. The inner diameter of the well is ≥100mm. The bottom of the well should be 150mm below the lowest point of the trough. The width of the straight section of the trough ≥ 10 times the width of the water surface of the weir. The highest water level downstream is lower than the lowest water level of the weir;
• The emission surface of the sensor probe should be parallel to the liquid surface. The distance between the lower end of the sensor and the highest liquid level should be ≥0.7 m;
• There should be no strong light, electromagnetic field and other radiation sources around the sensor;
• There should be measures to prevent rain and snow above the ultrasonic sensor.

Note in use:

• Because the places where sewage ultrasonic sensors are installed are places with relatively poor environment. Therefore, the host of the instrument should be installed indoors. There should be a dedicated person to take care of it. Conduct regular inspections of lines and sensors;
• The meter should be checked regularly.

Read more about: Waste water measurement

More Featured Ultrasonic Flow Meter

Sino-Inst, Manufacturer for Open Channel Flow Meters. It can measure a single sound-conducting liquid medium. It can measure even liquids such as water, seawater, oil, and slurry.

Sino-Inst’s Open Channel Flow Meter, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, the US, and other countries.

KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.

Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.

drurylandetheatre.com