Issues regarding the installation height of differential pressure level gauge transmitters: national standards + American standards
Thread Content
Petrochemical standards recommend that transmitters be installed below the lower pressure tap; if they are installed above it instead, what calculations need to be done? I guess it’s to perform a zero-point calibration using the pressure generated by the silicone oil in the capillaries, in order to eliminate its influence? API551 states that for differential pressure level gauges with diaphragm sealing, the transmitter can be installed above the lower pressure tapping point; but isn’t the pressure generated by the silicone oil in the capillary tube something that needs to be taken into account?
When the transmitter is installed above the lower pressure tapping, if the liquid level is below the installation position of the transmitter, it will detect negative pressure; it is necessary to calculate the negative pressure that occurs at a liquid level of 0, as this will not cause the silicone oil inside the capillary to vaporize
Just install it however you like; technology evolves rapidly. It was once said that flange-type capillary pressure transmitters couldn’t be used in negative-pressure environments, but now they can be installed even in complete vacuum conditions without any problem
Zero-point migration is required regardless of the installation location; differential pressure transmitters are generally installed below the two pressure tapping points to prevent damage to the diaphragm. For these questions of yours, even my great-grandson can answer them for you.