Instrument Air Dryers and the pressure dew point setpoint
Instrument Air Dryers and the pressure dew point setpoint
(OP)
Can someone explain to me setpoints on a desiccant instrument air dryer. Why are setpoints shown with these units -40 F/C? I understand when you compress air above atmosperic pressure the dew point temp will change. What does -40 F/C actually mean for the dew point temp for the compressed air in the piping? Any info would help.





RE: Instrument Air Dryers and the pressure dew point setpoint
Mike Henderson
RE: Instrument Air Dryers and the pressure dew point setpoint
RE: Instrument Air Dryers and the pressure dew point setpoint
RE: Instrument Air Dryers and the pressure dew point setpoint
When maintenance uses the air for air tools and other uses, that can create problems.
RE: Instrument Air Dryers and the pressure dew point setpoint
Agreed about dryers being sensitive to surge, so in my experience the instrument air system, which needs to be dry, has a larger dry air receiver downstream of the dryers to stabilize the flow through the dryers (normally the dessicant type). If there is to be a utility air system for tools or things like that which don't require low dew point air they'll either use a separate compressor with the air supply coming directly off a wet air receiver, or they'll provide a separate takeoff upstream of the dryers on the main compressor package, or depending on the client they'll just heavily oversize the dry air receiver and run the whole plant off that, including utility air.
Regards,
Mike Henderson
RE: Instrument Air Dryers and the pressure dew point setpoint
If you are lubricating instrument air then you have serious problems with moisture. As already mentioned by Mike, lower ambient temperatures requires lower ADP/PDPs.