Instrument air consumption calculation
Instrument air consumption calculation
(OP)
Hi guys,
As you know, on/off valves consume air in start-up / shutdown condition. My supervisor believes because these valves will not work simultaneously, considering 10% of them in air consumption calculation are enough.
But I think because they are "fail to close" and have "three way solenoid valve" after total SD, all of them consume instrument air simultaneously. So I consider 100% of them in instrument air consumption calculation.
What do you think?
Thanks much!
As you know, on/off valves consume air in start-up / shutdown condition. My supervisor believes because these valves will not work simultaneously, considering 10% of them in air consumption calculation are enough.
But I think because they are "fail to close" and have "three way solenoid valve" after total SD, all of them consume instrument air simultaneously. So I consider 100% of them in instrument air consumption calculation.
What do you think?
Thanks much!





RE: Instrument air consumption calculation
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Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
RE: Instrument air consumption calculation
After a shutdown they won't all need to open at the same instant.
You also have a lot of capacity in the airlines and air reciever.
RE: Instrument air consumption calculation
maybe i'm not right! but i think "three way solenoid valve" consumes air when it doesn't energize on/off valve!
RE: Instrument air consumption calculation
A 4 way solenoid will use air in both directions these are used on double acting valves with no spring.
RE: Instrument air consumption calculation
If you are using reciprocating compressors at more than about 50 psig, be sure to use 2-stage compressors with intercooling to save energy and maintenance costs. In my experience, single stage compressors for 90 to 100 psig systems always seem so attractive for initial cost, but their unavoidably high operating temperatures always result in much-greater-than-forecast operating and maintenance costs along with resultant reliability problems. In contrast, for nominal 90 to 100 psig systems, 2-stage reciprocating compressors rarely require anything beyond normal, scheduled maintenance for trouble-free reliable operation.
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.
RE: Instrument air consumption calculation