Is the earth ring of the electromagnetic flowmeter necessary? What's the function?
Not necessarily. The grounding ring is only for dielectric grounding and can absorb part of electromagnetic or pipe vibration interference.Usually grounding is in the form of earth ring, and there is a special sensor in the electromagnetic flowmeter sensor grounding electrode, the main purpose is to resist interference, as far as possible to make the instrument accurate measurement.(usually, if the pipe is metal, there is no need for a grounding ring, because the pipe is a large grounding device, and if the pipe is plastic, then the ground ring is needed for accurate data)In order to make the instrument accurate, the ground ring and ground electrode are simultaneous. We have all the electromagnetic flowmeters here.
The grounding ring is directly contacted with the medium through the grounding electrode, and then grounded with the instrument flange through the ground ring to achieve ground equipotential, so as to eliminate interference.
Often in some occasions it is not suitable with the grounding ring, for example, when measuring the strong corrosive medium, selective electrode often use PVC or PTFE lined pipe is the precious metals, especially for large diameter, it would not be possible with the grounding ring, the cost is too high. In this case, three electrodes are generally selected, of which two electrodes are used for measurement and the other is grounded.In general, if the pipe is made of metal material, it can also be not suitable for the ground ring. It will connect the flange and the pipe of the flowmeter and then connect it to the ground. It can also be used well, especially in the case of large caliber. If the small bore, with the ground ring does not matter, the cost will not be much worse. In addition, some users do not test the strong corrosive media, but the pipe is non-metallic, then it is necessary to match the ground ring, grounding is very important for electromagnetic. The magnetic field interference is fatal for electromagnetic, because we can take some measures for electric field shielding, but we have no way of magnetic field shielding, electromagnetic flowmeter installed so we must avoid the strong magnetic field.
