How are the electrodes of an electromagnetic flowmeter connected to the pipeline?
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When measuring corrosive media, electromagnetic flowmeters typically have their pipes lined with PTFE; the electrodes are made of metals such as Hastelloy C or tantalum, while the housing is usually made of carbon steel. My question is: how are the electrodes connected to the carbon steel part, and why doesn’t the corrosive medium leak through the gaps around the electrodes and cause corrosion in the carbon steel portion?
The electrodes of an electromagnetic flowmeter are not in contact with the meter’s housing; instead, they are fixed to the liner of the flowmeter. There are various methods of fixation, which depend on the material of the electrodes, the material of the liner, and the manufacturing process of the liner.
It’s true that the electrodes are fixed to the lining, but they still need to transmit electrical signals to the converter through both the lining and the carbon steel casing. Customers keep bringing up this issue for me; without understanding the process, it’s difficult to explain things clearly.
Don’t electrodes and lead wires have insulating layers? Moreover, electromagnetic flowmeters typically employ different anti-seepage measures for their electrodes and linings. You can look up the structure of electromagnetic flowmeters online – is that really that difficult?