Bring compressed air form 68psig to 130psig using 2000psig cylinders
Bring compressed air form 68psig to 130psig using 2000psig cylinders
(OP)
What we are looking for is the amount of 250 cubic feet cylinder at 2000 psig that we need to purchase to make up the difference between the instrument air (68 psi expected) and the test pressure of 130 psi.
The sytems total volume is 170 cu. ft. Medium is air. Temp will not be a factor.
How many cylinders will it take to bring the 68psig to 130psig in a 170cu. ft system?
Thanks for your help.
The sytems total volume is 170 cu. ft. Medium is air. Temp will not be a factor.
How many cylinders will it take to bring the 68psig to 130psig in a 170cu. ft system?
Thanks for your help.





RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders
Now turn your bottle volme into standard conditions at 2000 psig. Then compute the bottle volume at some number approaching 130 psig (how close you come is a function of how long you are willing to wait, I would use 145 psig myself) to standard conditions. Subtract the 130 psig number from the 2000 psig number and you get the standard cubic feet of usable gas in a bottle.
Divide the second number into the first to get the number of bottles.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders
Boyles Law Pt Vt = Pc Vc
RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders
Not sure how you calculated that, but it is wrong. The required volume is 716 SCF. If you assume that the bottles contain 250 SCF at 2000 psig (since if they hold a physical 250 ft^3 you would need a 60 inch ID "bottle" 12 ft long) which has a usable volume (at 145 psig terminal pressure) of 230 SCF. That says that you need 3.1 bottles.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders
RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders
I appreciate everyone’s help.
RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders
RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders
RobinHandy,
That is the beauty of eng-tips.com, when you make a mistake someone in the world will call you on it. I really love that feature of this site because I make mistakes all the time.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Bring compressed air form 68psig to 130psig using 2000psig cylinders