Application Guide for Gas Ultrasonic Flow Meters

Ultrasonic waves carry information about the flow rate of the fluid as they propagate through the flowing fluid. Therefore, the flow rate of the fluid can be detected by the received ultrasonic waves, which can be converted into a flow rate. According to the detection method, it can be divided into different types of ultrasonic flowmeters such as propagation velocity difference method, Doppler method, beam offset method, noise method and related methods.

Ultrasonic flowmeter is a kind of application that has only begun to be applied with the rapid development of integrated circuit technology in the past ten years. Non-contact instrument for measuring fluids that are not easily accessible and observed, as well as large pipe diameters. It is linked to a water level gauge for flow measurement of open water flows.

The use of ultrasonic flow is an ideal section because it does not change the flow state of the fluid and does not produce additional resistance, and the installation and maintenance of the instrument can not affect the operation of the production pipeline

A gas ultrasonic flowmeter is an instrument used to measure the flow rate of gases, which utilizes ultrasonic technology to measure the flow rate and flow rate of gases. Its working principle is to use the relationship between the speed of ultrasonic wave propagation in the gas and the gas flow rate at foot height, and calculate the flow rate of the gas by measuring the propagation time and distance of the ultrasonic wave.

Gas ultrasonic flowmeters have the following advantages:

1.Non-intrusive measurement: The gas ultrasonic flow meter does not require direct contact with the gas, so it does not interfere with the flow of the gas and does not affect the quality of the gas.

2.High-precision measurement: The gas ultrasonic flowmeter adopts digital signal processing technology, which can achieve high-precision measurement with an error of less than 1%.

3.Wide measuring range: Gas ultrasonic flow meters can measure a wide range of gases with a wide range of flow rates ranging from a few milliliters to hundreds of cubic meters per hour.

4.Easy to install and maintain: The gas ultrasonic flowmeter is simple in structure, easy to install, and does not require regular maintenance.

Gas ultrasonic flowmeter is widely used in petrochemical, electric power, metallurgy, mountain jujube environmental protection and other fields, and is used to measure the flow rate and quality of gas, which plays an important role in ensuring the stability and safety of the production process.

Hello,Ultrasonic flowmeter manufacturer imported from the United States - Kornke KNKEGlad for your question.

An ultrasonic flow meter is a non-contact measuring instrument that can be used to measure fluid flow and large pipe diameter flow rates that are not easy to touch and observe. It does not change the flow state of the fluid, does not produce pressure loss, and is easy to install; It can measure the flow rate of highly corrosive media and non-conductive media; The ultrasonic flowmeter has a large measuring range, and the pipe diameter range is from 20mm to 5m.;Ultrasonic flow meters can measure a variety of liquid and sewage flows; The volume flow measured by the ultrasonic flow meter is not affected by the thermophysical parameters such as temperature, pressure, viscosity and density of the fluid to be measured.

It can be made in both stationary and portable forms.

The temperature measurement range of ultrasonic flowmeter is not high, and generally only can measure fluids with temperatures lower than 200; Only when the fluid velocity is measured at the same time as the fluid density can the true mass flow value be obtained.

According to the installation method: pipeline type, external clamp type.

According to the measurement medium: liquid ultrasonic, gas ultrasonic.

The principle is the time difference method, in which the time required for sound waves propagating against the current and downstream is different, and the flow rate of the fluid is calculated according to the time difference.

The installation methods are: external sensor, plug-in sensor, pipe section sensor;

The structural forms are: split, integral, combined;

The output mode is: pulse output, current output (DC4 20mA), data communication output (RS485 communication, Modbus protocol).

Principle: Using the time difference method, the time required for sound waves propagating against the current and downstream is different, and the flow rate of the fluid is calculated according to the time difference.

No, I am an engineer in a production company that produces flow meters When the beam propagates in the liquid, the flow of the liquid will cause a slight change in the propagation time, and the change in the propagation time is proportional to the flow velocity of the liquid, and the relationship is in accordance with the following expression: where is the angle between the sound beam and the direction of the liquid flow m is the number of times the sound beam propagates in a straight line in the liquid d is the inner diameter of the pipe tup is the propagation time of the sound beam in the positive direction tdown is the propagation time of the sound beam in the reverse direction δt=tup tdown Let the sound velocity in the stationary fluid be c, the velocity of the fluid flow is u, and the propagation distance is l, and when the sound wave is consistent with the direction of the fluid flow (i.e., the downstream direction), the propagation velocity is c+u; Conversely, the propagation velocity is c-uTwo sets of ultrasonic generators and receivers (T1, R1) and (T2, R2) are placed at two places with a distance of l. When T1 emits ultrasonic waves in the forward direction and T2 in the reverse direction, the time required for the ultrasonic waves to reach the receivers R1 and R2 respectively is T1 and T2, then T1=L (C+U) T2=L (C-U) Since the flow velocity of the fluid is much smaller than the sound velocity in the industrial pipeline, that is, C>>U, the time difference between the two is T=T2-T1=2Lu cc Therefore, it can be seen that when the propagation velocity c of the sound wave in the fluid is known, the flow velocity u can be obtained as long as the time difference t is measured, and then the flow rate q can be obtained.

The method of flow measurement using this principle is called the time-of-flight method. In addition, the phase contrast method, frequency difference method, etc. can also be used.

1. At present, the ultrasonic flowmeters produced in China are all made of 1MHz, and the gas cannot be used as a medium to transmit, so it cannot be measured.

2. The principle of ultrasonic flowmeter: in the process of measuring the fluid, the propagation speed of ultrasonic waves in the countercurrent is slightly smaller than that in the downstream flow, and the flow rate is proportional to the time difference under the condition that the pipe diameter remains unchanged.

Imported ultrasonic waves can measure gas mediums, and domestic ultrasonic waves cannot achieve the purpose of measuring gas mediums.

Ultrasonic meters can measure gas flow, and time-of-flight ultrasonic flowmeters are popular in the field of natural gas metering. To account for 90% of the market.

In the flue gas field, UF200 is the field of flue gas measurement.

With the advancement and development of technology, in the past two years, the gas ultrasonic flowmeter has developed rapidly.

In the fields below DN100, gas ultrasonic flowmeters have been popularized and have been widely used in the field of gas metering.

For large diameter gas flow measurement, such as flue and pipeline with a pipe diameter of more than 2 meters, gas ultrasonic flowmeter is also promoting the use, ultrasonic gas flowmeter in the field of large pipe diameter, technology and advantages are obvious, is the most economical and reasonable technology and technology in all flowmeters. For example, UF200 flue gas ultrasonic flowmeter is used in this field.

Among the ultrasonic flowmeters, the time-of-flight ultrasonic flow method is the most mature and reliable, and the use of other ultrasonic principles such as Doppler method has certain limitations.

The ultrasonic flowmeter uses the time-difference measurement principle

After the transmission signal of one probe passes through the pipe wall, the medium, and the other side of the pipe wall, it is received by another probe, and at the same time, the second probe also transmits the signal and is received by the first probe, because it is affected by the flow rate of the medium, there is a time difference δt between the two, and the conversion relationship between the flow velocity v and the time difference δt can be obtained according to the estimation V=(C2 2L) δt, and then the flow value q can be obtained.

The clamp-on ultrasonic flowmeter has high precision, large measurement range, and the measurement results are not affected by conductivity, pressure, temperature and viscosity, and are not in contact with the medium, especially suitable for the measurement of corrosive media, with advanced signal processing technology and huge database. The clamp-on type has high precision, large measurement range, the measurement results are not affected by conductivity, pressure, temperature and viscosity, no contact with the medium, especially suitable for interactive operation, friendly interface, easy installation, no need to interrupt the fluid or process, no need to reduce the diameter, at the same time, the probe of Flexim ultrasonic flowmeter can cover the range of DN6 DN6500 pipe diameter, with the advantages of German products, high cost performance, timely service and so on.

The principle is the time difference method, which began to be used to measure liquid media, and there are already gas ultrasonic flowmeters for measuring gases.

Just like the ultrasound in the hospital, it is measured by the sound wave band.

It is mainly used to measure liquids, and other media are very poor.

There are two working principles of ultrasonic flowmeters: (1) ultrasonic time-of-flight method (2) ultrasonic Doppler method.

Since the ultrasonic Doppler method is only used in liquid pipes containing particles, it has certain limitations, so its use is limited to small flow liquids, such as in the medical field.

The most widely used is the ultrasonic time-of-flight method.

Among them, UF200 can measure the pipe diameter of large cross-section of flue gas.

1. Working principle: The time difference method mainly uses the proportional relationship between the time difference between the signal received by the upstream and downstream sensors and the fluid velocity, measures the time to obtain the time difference, and then calculates the flow rate under working conditions, and then calculates the volume flow rate according to the pipe size (outer diameter, wall thickness), and then calculates the mass flow rate from the density (liquid) or molar molecular weight (gas) (which can be found on the Internet);

2. Measurable medium: any liquid and gas.

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The working principle of the ultrasonic flowmeter: the ultrasonic flowmeter uses the time difference method to measure the flow rate of water, and the flow rate is multiplied by the cross-sectional area. According to the flow direction of water, it is divided into upstream and downstream, simply put, the upstream and downstream are each equipped with a sensor probe, which can emit ultrasonic waves, the upstream emits an ultrasonic wave, and the downstream receives a transmission time; At the same time, the downstream sensor also emits an ultrasonic signal, and the upstream one receives it, and generates a time, the length of these two times is different, and their time difference is a function of the water flow velocity.

In this way, the flow rate of the water is carried on the ultrasound, and the flow rate can be calculated by calculation.

Ultrasonic flow meters are capable of measuring gases, liquids, and solids.

How the ultrasonic flowmeter works:

Taking advantage of the fact that ultrasonic waves can penetrate objects, an ultrasonic transmission device is installed outside the fluid pipeline to measure the fluid flow rate in the pipe. We call this form a clampon-type flow. It is mainly used for large-diameter pipeline flow measurement, and sometimes it is necessary to install an ultrasonic transmission device directly in the pipe, which is called a wetted ultrasonic flowmeter.

Ultrasonic flow meters are capable of measuring gases, liquids, and solids, such as slurries.