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Compressor head.

Started by WGB, February 01, 2010, 05:16:39 AM

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BruceM

For those who might need more air and two stage compressors, I like Eaton compressors.  Good support and discounted freight rates. 

http://www.eatoncompressor.com/page/page/518643.htm



Jedon

The HF pump doesn't have a clutch release and the cheapest of the Eaton's didn't either, how do we find one with a clutch so it will stop running when the tank is full?

Wizard

First link of inline 2 compressor is certainly not cast iron,  look at weight, 23lb.  Too light.

I have a single cylinder 1hp compressor from Auto princess and it weighs heavier than this waiting to be put together with good AC induction motor once I find a chance to get someone to cut off the platform welded to the old orginal platform and cut this free from equally beat up air tank with big dent had a hole that was patched no less, with braze YIKES! I put it out of comission by taking apart old head permenantly!  The head was reused from semi-hemi small freon compressor.  Valves are disc type and extremely worn out and rusted solidly that I cannot extract valves from the piston tops for resurface, wrist pins are tool steel with thick chrome plating, extremely worn but other than that, good and does not have rings at all.  I could not find the close match without machining too much from the small end of cast-iron rods.  Seals were done with stamped out lead sheet gaskets. Original design and this was reason gasket squirted out and blew out.)
I have photos of this old freon compressor if anyone wish to see.

Anyone ever build in a configuration like this:  compressor head with flex line with pressure switch cut off, so can fill up air pig tank?  I was wondering about the air pulses thru the air hose.

Cheers, Wizard

BruceM

#4
Jedon-
The Eaton compressors have pneumatic valve unloaders that keep the intake valve open.  This is used to stop air compression, and is the way it is done in most non-hobby compressors.

A pilot valve is then used to control this unloader; Control Devices makes these and sells them through Grainger and other outlets.  At Grainger this is $19.

http://www.grainger.com/Grainger/items/3X818?Pid=search

On my remote controlled  6/1 with ST-3 and Eaton 2 stage compressor setup, I added a three way pneumatic toggle switch controlled with an RC servo going to the compressor unloader line.  The unloaders are kept pressured when no air is requested. When air is switched on remotely, then the unloader valves get the pilot valve output.  Eaton suggested this arrangement instead of a jack shaft with electric clutch, and estimated that I'd loose 1/2hp in piston and fan drag.  For long days of electric only service, I pull the compressor belt.  It's a bit crude, but it's very simple, and has served well.

Wizzard-
The output of a compressor is very hot, so a coiled/curved copper strain relief is often used for at least the first section.  It would normally be steel or copper pipe up to the tank.  If the tank is remote, then depending on the HP of the compressor, I'd want 20 feet or more of copper or steel line.  I have about 30 foot of copper on my remote 500 gallon tank setup, 20 foot of that is buried.
After that the buried pipe is 1" PVC,  no above ground PVC for safety reasons. You can't touch the 3/4" copper line 6 feet from the compressor without getting burned, after it has run for 20 minutes.

Best Wishes,
Bruce






Wizard

#5
Oh right!  Hot air...!  Suppose I put in small chamber to allow air to trumble around and coiled copper line to cool the air before reaching the flex air line.  The tank is portable while compressor set is not.

The 1 cyl compressor is small, around 9cfm at 90PSI but this is intermittent duty due to air pig tank and I plan to rotate compressor low rpm (300-400 PSI for noise and motor is only 1/4 or 1/2HP 115V, 1750rpm).

I have not found a used semi sealed external twin cylinder freon compressor to replace the old one as I rather liked the size and bore size is 1.25" dia by about 2" stroke or so.

If I can find the wrist pins just a fraction larger, length no matter this would be nice.
If I could get this rebuilt, I'd convert this compressor to have inlet air from head instead of through the crankcase.  Only small negative is no rings at all, just plain pistons.

Crank is unique.  Pair of 180 out of phase eccentrics about 2" dia round making for wildly big end and extreme tiny small end rods.

pictures:








Cheers, Wizard

BruceM

Another solution to the hot air problem would be to put a small air tank near the compressor, which would feed your mobile tank via your flex air hose.