These errors should be avoided when using electromagnetic flowmeters
Electromagnetic flowmeter, with high precision, long life characteristics, in chemical industry, environmental protection, metallurgy and other fields and industries have been applied. However, in the process of use, due to the influence of many factors, it is easy to cause the inaccurate measurement results of the electromagnetic flowmeter. So what are the reasons for the error of the electromagnetic flowmeter?
1. The liquid in the tube is not filled
Due to insufficient back pressure or poor installation position of the flow sensor, the liquid in the measuring tube is not filled, and the fault phenomenon is different due to the degree of insufficiency and flow status.
If a small amount of gas is stratified flow or wavy flow in the water pipe, the fault phenomenon shows that the error increases, that is, the measured flow value does not match the actual value;
If the flow is bubble flow or plug flow, the fault phenomenon not only does not match the measured value with the actual value, but also causes the output to shake because the gas phase covers the electrode surface instantaneously.
If the gas phase part of the cross section of the flow area increases in the stratified flow of the horizontal pipe, that is, the degree of liquid filling the pipe increases, the output sloshing will occur.
If the liquid is not fully filled, so that the liquid level is below the electrode, the output overfull phenomenon will occur.
2, liquid contains solid phase
The liquid contains solids such as powder, particles or fibers, which may cause faults. ① slurry noise; ② The electrode surface is contaminated; (3) The electrode or lining is covered by a conductive or insulating deposit layer; ④ The lining is worn or covered by sediment, and the circulation cross-sectional area is reduced.
3. Problems caused by improper selection of electrode and grounding ring materials
Due to the mismatch between the material and the measured medium, the electromagnetic flowmeter and the parts in contact with the medium have electrodes and grounding rings, and the mismatch is in addition to the corrosion resistance problem, as long as the electrode surface effect.
