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How is the flowmeter to achieve flow regulation and control?

The structure of the electromagnetic flowmeter is mainly composed of a magnetic circuit system, a measuring conduit, an electrode, a casing, a lining and a converter.

Magnetic circuit system: its role is to produce a uniform DC or AC magnetic field. The DC magnetic circuit is realized by a permanent magnet, which has the advantages of simple structure and less interference by the alternating magnetic field, but it is easy to polarize the electrolyte liquid in the measuring duct, so that the positive electrode is surrounded by negative ions, and the negative electrode is positive ion Surrounding, that is, the polarization phenomenon of the electrode, and causing an increase in internal resistance between the two electrodes, thus seriously affecting the normal operation of the meter. When the diameter of the pipe is large, the permanent magnets are correspondingly large, bulky and uneconomical, so the electromagnetic flowmeter generally adopts an alternating magnetic field and is generated by the excitation of a 50HZ power frequency power source.

Measuring catheter: its function is to let the conductive liquid to be tested pass. In order to make the magnetic flux diverted or short-circuited when the magnetic flux passes through the measuring catheter, the measuring catheter must be made of non-magnetic, low electrical conductivity, low thermal conductivity and mechanical strength. Non-magnetic stainless steel, FRP, high strength can be selected. Plastic, aluminum, etc.

Electrode: Its function is to extract and sense the induced potential signal. The electrodes are typically made of non-magnetically conductive stainless steel and are required to be flush with the liner so that the fluid passes without obstruction. It should be installed in the vertical direction of the pipe to prevent deposits from accumulating on it and affecting the measurement accuracy.

Enclosure: Made of ferromagnetic material, it is the cover of the distribution system excitation coil and isolates the interference of external magnetic field.

Lining: A complete electrical insulation lining on the inside of the measuring tube and on the flange sealing surface. It directly contacts the liquid to be measured, and its function is to increase the corrosion resistance of the measuring catheter and prevent the induced potential from being short-circuited by the metal measuring tube wall. Most of the lining materials are PTFE plastics and ceramics that are resistant to corrosion, high temperature and wear.

Converter: The induced potential signal generated by the liquid flow is very weak and is greatly affected by various interference factors. The function of the converter is to amplify and convert the induced potential signal into a unified standard signal and suppress the main interference signal. Its task is to amplify the induced potential signal Ex detected by the electrode into a unified standard DC signal.

Many people have such doubts, can the flow meter do flow regulation and control?

Xiaobian can definitely tell you here that almost all flowmeters can adjust and control the flow.

We know that the flow meter can output 4-20 mA current signal. In the flow regulation and control system, the main function of the flow meter is to convert the measured flow into a current signal and transmit it to the control system. The control system is used to open and close the valve to realize the flow. Adjustment and control.

To achieve flow regulation control, there must be three types of equipment on site: intelligent flow meters, flow control systems, regulating valves or valves. If there is no control system and valve at the site, then we need to match the flow quantitative controller and electric control valve to meet the requirements. The flowmeter is used as the measuring mechanism to measure the flow of the field and convert the flow into a 4-20 mA signal. The signal is sent to the control system. We need to set the required flow in the control system. When the flow reaches the setting. At the time, the control system sends a signal to the regulating valve, which opens or closes the valve, and the entire system works like this.

Therefore, the flow meter can really adjust and control the flow, and it is accurate and efficient.

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