Damping pressure gauge fluctuations

[skuntz]

We will be monitoring room pressure with a very low pressure (+/- 0.1 w.c.) differential transducer. There is air circulating in the room because of fans. I would welcome suggestions as to how to eliminate pressure fluctuations seen by the transducer.

 

[danw2]

I bought 10' lengths of 0.020" ID capillary tubing, brazed one end to a pipe fitting (that fit the process connection port on the pressure transmitter), stuck the the other end of the capillary into a hole I drilled into a scintered filter and super-glued the OD of the capillary to filter. It cut the oscillations dramatically.

I honestly don't know if the scintered filter or the long capillary had the greater effect.

There also the approach of averaging at whatever is taking the pressure readings.

 

[Niwot]

danw2 is correct. You have 2 options - Mechanical or Electronic damping. danw2 is using a mechanical method. For electronic damping, check your DP transducer to see where its damping (response time)is set. For example, if it as at .4 sec, you can bump it up to 1.2 sec and it will be averaging the signal over a longer time frame. The resultant response time will be increased, but the trade-off is a quieter signal. If your transducer does not have this feature, then you could possibly dampen the signal in a control room or computer.