Air pump for achieving higher pressure ?
Air pump for achieving higher pressure ?
(OP)
Hi all,
A simple question..... If I have a 100Psi air pump (Pump # 1) & i enclose that pump in a sealed enclosure held at 100Psi. What pressure should i expect out of the enclosed pump if i am measuring the output pressure at atmospheric pressure level? Will it be simply 100Psi or 100+100= 200Psi or will it be 100x100 = 10000Psi ? I am an electronic guy thinking of above scenario... Thanks in advance
A simple question..... If I have a 100Psi air pump (Pump # 1) & i enclose that pump in a sealed enclosure held at 100Psi. What pressure should i expect out of the enclosed pump if i am measuring the output pressure at atmospheric pressure level? Will it be simply 100Psi or 100+100= 200Psi or will it be 100x100 = 10000Psi ? I am an electronic guy thinking of above scenario... Thanks in advance





RE: Air pump for achieving higher pressure ?
If you raised the suction pressure to 100 psig (call it 114.7 psia), then the same 7.8 ratios would give you 880 psig discharge. In the real world, you'd have many auxilliary considerations (e.g., first stage clearance, vessel and piping pressure rating, etc.), but that is the magnitude of the change.
David
RE: Air pump for achieving higher pressure ?
Ted
RE: Air pump for achieving higher pressure ?
David
RE: Air pump for achieving higher pressure ?
RE: Air pump for achieving higher pressure ?
Compressor clearance is the unswept volume in the cylinder. The larger this number is, the fewer compression ratios the cylinder can do. On a multi-stage compressor you can balance the capacity of the stages by adding or subtracting clearance. [I just wrote a detailed example and realized that compressor guys would get it but no one else would and deleted it.] The arithmetic is CR=(V1/V2)^k so increasing clearance will decrease the compression ratios (i.e., if V1 was 6 in^3 and V2 was 2 in^3, then if I increase clearance 10% of V1 then the ratio goes from 3.0^k to 2.5^k or 4.66 compression ratios to 3.7 compression ratios for air).
Now if your compressor is a flooded screw then none of this matters. Flooded screws are positive displacement machines like a recip, but they tend to have pretty low maximum suction pressure and maximum discharge pressure (e.g., a Gardner Denver SSY air compressor has a max suction of 30 psig and a max discharge of 250 psig and you couldn't safely give it 100 psig suction).
David
RE: Air pump for achieving higher pressure ?
RE: Air pump for achieving higher pressure ?
RE: Air pump for achieving higher pressure ?
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Air pump for achieving higher pressure ?
Ted
RE: Air pump for achieving higher pressure ?
What with the oxygen content, the oil vapor and the heat of compression, sometimes they think they're Diesels.
They're not built to contain Diesel explosions.
Mike Halloran
Pembroke Pines, FL, USA
RE: Air pump for achieving higher pressure ?
What kind of oil have you seen that autoignites below 350F? Are you lubricating with Ether?
I've never seen a recip that did not have a high temp kill and they've all been set at 350F or less. The heat of compression calculation is T(out)=T(in)(CR)^((k-1)/k). So high temp is only a problem with a lot of compression ratios, not with any particular discharge pressure.
David
RE: Air pump for achieving higher pressure ?
... but we're talking about a homebrew rig here; no kill switch guaranteed to be present.
Mike Halloran
Pembroke Pines, FL, USA
RE: Air pump for achieving higher pressure ?
David
RE: Air pump for achieving higher pressure ?
RE: Air pump for achieving higher pressure ?
Mike Halloran
Pembroke Pines, FL, USA
RE: Air pump for achieving higher pressure ?
http://www.haskel-usa.com/air_pressure.htm
If you have a pressure booster and can use air then you may as well start with a 100 psi compressor and boost that.
RE: Air pump for achieving higher pressure ?
RE: Air pump for achieving higher pressure ?
RE: Air pump for achieving higher pressure ?
RE: Air pump for achieving higher pressure ?
Perhaps it would help if you told us why and for what purpose you want to pressurize this thing that has a volume of 500cc.
Ted
RE: Air pump for achieving higher pressure ?
Mike Halloran
Pembroke Pines, FL, USA
RE: Air pump for achieving higher pressure ?
http://www.airforceairguns.com/handpump.html
It is used to charge a 490cc tank to 3000psi on an air rifle. The air rifle limits the pressure, not the pump.
Ted
RE: Air pump for achieving higher pressure ?
Interesting link for the air pump. That will, of course, require far more energy than a hyraulic pump.