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| spudamine |
 Posted: 04/30/2010 14:21 PM Post subject: |
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Master Sergeant
Joined: 23 Nov 2008
Posts: 171
4.29 Spud Bux
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| Quote: | | i dont think a case is nessecary, just mount everthing to the compressor like i did |
It's not necessary but I like building things to last so this is going to be rugged, portable and easily stowed away. Besides these fans are a bit too big to attach with a few cable ties and I'd rather not have the 240v power lines dangling around near the blades. 
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| POLAND_SPUD |
| Posted: 05/26/2010 11:15 AM Post subject: |
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Lieutenant General
Joined: 13 Oct 2007
Posts: 4387
11901.36 Spud Bux
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I've noticed that inlet air temp. has huge effect on the temperature of the compressor... any idea how to calculate it ?
I found this equation on wikipedia
I am not good at calculating stuff... any idea what the effect of inlet temp. on outlet temp. might be ??
Also it seems that lower inlet temperature has an effect on efficiency too
| Quote: | | ... if 90 deg. F intake air is tempered with cooler air from another source to 70 deg. F, the 20 deg. F temperature drop will lower operating costs by almost 3.5 percent |
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| spudamine |
| Posted: 05/26/2010 12:16 PM Post subject: |
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Master Sergeant
Joined: 23 Nov 2008
Posts: 171
4.29 Spud Bux
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| Hmm, before we get entangled in maths how have you come to this conclusion, presumably you would need to have your air supply significantly above or below the ambient temperature of the compressor to prove this?
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| POLAND_SPUD |
| Posted: 05/26/2010 13:39 PM Post subject: |
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Lieutenant General
Joined: 13 Oct 2007
Posts: 4387
11901.36 Spud Bux
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nope.... I moved my setup to the greenhouse and on some days it is over 120 deg F there... so in this case inlet temp = ambient temp
lol I don't have to tell you that the fan is almost useless in such situation ? I wondering whether it is just a result of less efficient cooling or whether the increase in inlet temperature is a significant factor
If someone could answer this question then maybe we can form a very general rule - place the compressor in the coldest place you can find
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| spudamine |
| Posted: 05/26/2010 15:05 PM Post subject: |
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Master Sergeant
Joined: 23 Nov 2008
Posts: 171
4.29 Spud Bux
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| Quote: | | If someone could answer this question then maybe we can form a very general rule - place the compressor in the coldest place you can find |
either way you're going to win doing that
my money is on the fact that the reduced air cooling is more of a
killer than the inlet air being warmer. In my test the compressor was pumping to atmosphere and it still got to 50*c with no fans. I guess I should repeat it at pressure, the difference is the contribution from compression heating, and running the motor harder...
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| POLAND_SPUD |
| Posted: 05/26/2010 17:38 PM Post subject: |
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Lieutenant General
Joined: 13 Oct 2007
Posts: 4387
11901.36 Spud Bux
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yeah that's what I thought at first, but then I noticed that the air reservoir got pretty hot too (normally it doesn't or at least I haven't noticed that)
ohh BTW I also noticed that the chamber on my semiauto gets pretty hot after about 40 or so shots... (not only when it is hot)
apparently that's a result of compression heating of air in the chamber as it fills the gun after each shot.. I guess it's not a problem on an all metal gun but it's something worth taking into consideration if you want to build all PVC semis
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| spudamine |
| Posted: 05/26/2010 23:53 PM Post subject: |
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Master Sergeant
Joined: 23 Nov 2008
Posts: 171
4.29 Spud Bux
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well on the bright side hotter air = moar power, as long as you fire it before it cools down and the pressure drops 
hopefully work on my compressor will be finished in a week or two and I can start on my BTB style balanced hammer valve.
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| spudamine |
| Posted: 08/20/2010 13:05 PM Post subject: |
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Master Sergeant
Joined: 23 Nov 2008
Posts: 171
4.29 Spud Bux
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I got around to finishing this at last, the case is built out of scrap steel angle and some galvanised steel sheet, the fans are mounted in the ends in a push pull arrangement which gives very good airflow around the compressor shell.
There's a nice shiny stainless steel glycerine filled guage, individual controls for the compressor and fans, a quick release on the output, threaded air and service inputs for potential upgrades and an IEC mains inlet
the hose is a hydraulic one with a quick release fitting on both ends so it can be shared between this and my hand pump (the power tends to go off when the zombies attack )
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| together with it's 'arm powered' brother and shared high pressure hose |
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| jackssmirkingrevenge |
| Posted: 08/20/2010 13:48 PM Post subject: |
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aspiring machinist
Joined: 15 Mar 2007
Posts: 18061
32519.23 Spud Bux
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| spudamine wrote: | | (the power tends to go off when the zombies attack ) |
Well played! I have plans to rig my compressor to my bicycle for the same reason! 
But seriously, looking extremely professional there, puts most other compressor setups to shame.
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