As a kind of flow meter, the electromagnetic meter is widely applied. Because of its simple structure, the flow that passes through the flow meter will not suffer from pressure loss. The electromagnetic meter can measure domestic waste water, industrial waste water, and can even measure the flow of liquid-solid two phases. The main characteristics of electromagnetic meter are: The measurement process is not easy to be affected by the density, temperature and viscosity of the liquid; The scale of speed measurement is relatively wide. Of course, the electromagnetic meter has some limitations because it only measures conductive liquids, not gases and vapors. So what aspects should be considered in the selection of electromagnetic meters?
The medium measured by the electromagnetic meter should meet the requirement on the conductivity, which is required to be greater than 5μs/cm.
The accuracy of the electromagnetic meter is high, because the measurement range of liquid flow meter is large. If the measurement range is large, the accuracy must be small. And the larger the range, the larger the error, so the accuracy needs to be strictly controlled. The accuracy of the precision flow meter is from 0.5 to 1 level, while the accuracy of the conventional glass and gold converter is 2.5 level. That's a big difference. In the measurement and billing, the high precision electromagnetic meter should be selected.
The flow rate of electromagnetic meter is required to be between 0.5 and 15m/s, and the reasonable flow rate is generally between 1.5 and 3m/s. If the flow rate is too fast, and if there are particulate matters, the lining of tetrafluorine may be scraped. The electromagnetic meter with appropriate flow rate and caliber should be selected.
Because the liquid is not matched with the electrode or the grounding ring, there will be some shortcomings in the device. In addition to the corrosion problem, this mismatch will also lead to the appearance effect of the electrode, which mainly includes: Chemical reaction, polarization phenomenon and catalyst effect. Ground rings have the same problems to a lesser extent.
If the liquid is assumed to contain particles, it may lead to the following disadvantages: Electrode and fabric surfaces covered by the accumulation layer, fabric wear and smaller pipe cross-sectional area. There is a layer of solid hanging on the inner wall of some liquid that has relatively simple crystallization when the fluid flows through the flow meter. Because the same problem exists in other types of flow meters, the flow meter that has a very short pipeline and simple disassembly can be selected, which can be easily disassembled to stop the protection after crystallization.