Air entrapment in instrument sensors 1

[jsearl]

I was just wanting to confirm that air trapped at the face of an instrument sensor designed and calibrated to measure water under pressure, would cause an incorrect or unreliable pressure to be recorded.

Thanks

 

[PowerfulStuff]

jsearl,
Gas trapped in a liquid pressure transmitter will cause innacuracy due to the change in head that results. For water this is roughly 100 kPa/10m. It will also slow down response speed as the gas is much more compressible than the liquid. Normally a liquid transmitter will be connected at the lowest point of a pipeline with a continuous drop to allow any gas to escape.