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 used. Plastic, aluminum, etc.
Vortex flowmeter installation method
1. The vortex flowmeter can only be measured in one direction. The installation should pay attention to ensure that the direction of the medium flow is consistent with the direction indicated by the flowmeter arrow.
2. The best installation method of the vortex flowmeter is vertical installation, and the medium passes through the flowmeter from bottom to top. Install the flowmeter on a vertical pipe with the flow direction from bottom to top.
3. When installing horizontally, the flowmeter must be installed in the high pressure zone of the whole system and ensure the corresponding outlet pressure; do not install at the highest point of the pipeline, because the highest point is often gas accumulation, the pipeline is not full, and the outlet cannot be directly emptied.
4. When measuring high temperature fluid, try to use vertical installation; if you have to install horizontally, please install the transmitter part of the flowmeter vertically downwards or horizontally to avoid excessive temperature; pay attention to air flow at installation location Or well ventilated.
5. Straight pipe section requirements: at least 15 times the pipe diameter before the flow meter and 5 times the pipe diameter after the flow meter. If there are elbows, indents, expansions and other sources of interference in front of the flowmeter, the diameter of the flowmeter should be 30–40 times, and the diameter of the flowmeter should be 6 times. The flow meter should be installed upstream of the regulator valve, pressure or temperature sensor.
6. When installing, pay attention to the pipe diameter should be slightly larger than or equal to the inner diameter of the instrument.
7. When using the sealing ring, the inner diameter of the sealing ring should be slightly larger than or equal to the inner diameter of the instrument, and the center of the sealing ring is at the center of the pipe.
ltrasonic flowmeter installation
The time difference ultrasonic flowmeter is a competitive flow measurement method in the world today, and its measurement line accuracy is higher than 1.0%. Due to the diversity of the industrial site, especially the environment around the pipeline, how to install and debug the ultrasonic flowmeter according to the specific environment has become an important topic in the field of ultrasonic flow measurement. This procedure explains the installation details of the ultrasonic flowmeter; It further fully demonstrates the advantages of accuracy, reliability and stability of the ultrasonic flowmeter, greatly reducing future maintenance work and even maintenance-free.
Ultrasonic flowmeters should be aware of the site prior to installation, including:
1. What is the distance from the host at the installation of the sensor;
2. Pipe material, pipe wall thickness and pipe diameter;
3. Year of the pipeline;
4. Type of fluid, whether it contains impurities, bubbles, and whether it is full;
5. Fluid temperature
6. Whether there is interference source at the installation site (such as frequency conversion, strong magnetic field, etc.);
7. The temperature of the four seasons at the host site;
8. Whether the power supply voltage used is stable;
9. Whether remote signals and types are required;
According to the site conditions provided above, the manufacturer can configure the site conditions and, if necessary, special models.