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Unread postPosted: Thu Dec 18, 2008 11:33 pm
Author: Gippeto
I did have the opportunity to see the insides of one of these.(A piston compressor type.) :)

The output from the compressor enters the case proper, the output lines simply lead through the case wall.

I suspect this is largely to allow any oil in the gas to drop out before the gas enters the lines to the heat exchangers.

The motor/compressor unit is well balanced, and mounted on springs inside the housing, minimizing noise, and its transmission to the case.

Unread postPosted: Fri Dec 19, 2008 4:37 am
Author: maggotman
ok i cut one open and it is as Gippeto said.

my concern now is the strength of the case as it would be under pressure
now i no when they are in the fridge they are under pressure any one no how much ?

Unread postPosted: Fri Dec 19, 2008 7:54 am
Author: psycix
Could you describe it more clearly?
You mean that the case is connected to the OUTPUT and may thus be under high pressure or connected to the INPUT meaning its under feeding pressure?
Is the case part of the system,or is it just there to hold in some noise and hold oil?


I'm planning to feed my fridge compressor with my 8 bar compressor as soon as I have the proper connections to connect the thing.
Also, the thing refuses to start up within 30 seconds of turning it off after a run. Maybe the 8 bar feed can give it a slingshot to help it start.

Unread postPosted: Fri Dec 19, 2008 9:56 am
Author: Gippeto
The compressor outputs to the case.

The case then outputs to the high pressure lines.

Some pictures. :)

http://s245.photobucket.com/albums/gg76 ... ompressor/

Unread postPosted: Sun Dec 21, 2008 7:48 am
Author: psycix
Hmm but wouldnt that mean that the pressure on the back side of the piston is high, meaning that the actual working stroke is the stroke where it sucks in air?
And would that mean that using a higher feeding pressure would help it start?

Also, what happens if the input pressure is higher then the output? Does it just flow through until the air is equal, or does the piston pump like its on crack or wont it work at all?

Unread postPosted: Sun Dec 21, 2008 6:45 pm
Author: Daltonultra
A multi-stage compressor would function, but it wouldn't necessarily get you more pressure. At worst, it might allow you to reach the same pressure faster, though. Basically, when a single pump would begin to bog down because of differential pressure, a two-stage compressor would have less differential pressure in each stage, making it easier for the pumps to work.

If you use two 250psi pumps, you could (unless the math goes screwy in a way I'm not familiar with) produce 500psi. The second pump would still be operating at a differential pressure of 250psi. As long as the case and tank can take 500psi, it's all good.

Actually, my ideal example would be using two tire-inflator pumps. Most 12V inflators are rated for 300psi, but getting them there is almost impossible. Using two in sequence might actually let you get to a real 300psi.

Unread postPosted: Mon Dec 22, 2008 9:04 am
Author: psycix
I know dalton, but I am only speaking about fridge compressors, and to speed the thing up (not to up the pressure), feed it with 8 bar.

Unread postPosted: Mon Dec 22, 2008 9:15 am
Author: ramses
my suggestion would be to fill the tank to 8 bar before you hook the 8 bar to the fridge compressor. I don't know if a scroll pump with an induced pressure differential would turn, but it's probably not worth the risk. a pump with a piston (like most real air compressors) would be fine.

Unread postPosted: Thu Dec 25, 2008 12:17 pm
Author: maggotman
conected up just one and it would go past 600ps trashed my pressure gage tho need one that will got higher got the gage to go past maximum then past up agenst the 0 mark
as for feeding it with air get more pressure hell of alot faster but my gage wont go that hi to see if their is a pressure increase

any one no a a uk supplier were i can get a gage that will go up to about 2000psi ?

Unread postPosted: Thu Dec 25, 2008 12:19 pm
Author: maggotman
conected up just one and it would go past 600psi trashed my pressure gage tho need one that will got higher got the gage to go past maximum then past up agenst the 0 mark
as for feeding it with air get more pressure hell of alot faster but my gage wont go that hi to see if their is a pressure increase

any one no a a uk supplier were i can get a gage that will go up to about 2000psi ?

very happy my friend gave me a box of ss fitting rated to 30 kpsi he got from work

Unread postPosted: Thu Dec 25, 2008 12:45 pm
Author: POLAND_SPUD
LOL 600 psi.. I hope you are fully aware that's way more than what they were designed to handle ??

if you plan to up the pressure (not that I think is neccessary - 600 psi is a lot) take some basic safety precautions...

Unread postPosted: Thu Dec 25, 2008 1:00 pm
Author: maggotman
yes ime not storing the air ime using m10 pipe and every thing is pressure rated also weiring goggles past 300psi filled a my marble canon to 400 and fired it sounded like a rifle lol

Unread postPosted: Sat Dec 27, 2008 10:40 am
Author: psycix
Pump it to 500 (if possible/safe) and it will sound like a cannon. :D

Unread postPosted: Fri Jan 02, 2009 7:34 pm
Author: maggotman
well i found a gage at collage its an old oxygen one that goes from 0 to 5kpsi
well i conected it to my fridg pump to be surprised it will make 1000psi

Image

crap picture i had to put tape over the flash to take it

Unread postPosted: Fri Jan 02, 2009 7:49 pm
Author: Gippeto
You did read this thread right?

You do understand that the case is being pressurized?

The case on mine measured .120 wall thickness, @ 1000psi, you are very close to the burst pressure of the case.

Please note, I'm NOT talking about working pressure here, I'm talking FAIL, as in...Ka-Freaking BOOM.

Do I need to point out that bursting the case @ ~1000psi will not be a fun thing to do?

I strongly recommend that you back off the pressure.


Edit: Scrolling up through this thread, I see that you do know that the case is pressurized.

I'm left shaking my head. :?