Bauer compressor

[CraigAClark]

I sure appreciate the responses, folks. You guys are awesome!
Is the PMV some type of pressure relief type valve keeping some back pressure in the filter stack? How does it affect air quality?
I'm going to look at the compressor this afternoon. Looking at the photos I think I need to put a cord on it in order to run it, I'm not sure if that will be possible. Is it possible to inspect the valve and make a reasonable judgement as to its condition without running it? Are they expensive to replace?

Make sure you see the the machine run! You can get an idea if the PMV is working by seeing if pressure starts to build in the hose immediately or if there is a dely. The delay usually can be seen as the machine runs 2-3 minutes and the some pressure starts to build, followed by a quick jump to around 1800 psi (normal factory setting) and then builds gradually to the relief pressure.

Craig

 

[crpntr133]

Is the PMV some type of pressure relief type valve keeping some back pressure in the filter stack? How does it affect air quality?

The PMV keeps pressure on the filter. It increases the dwell time of the air and thus makes it "cleaner".

There is a lot of great info in this forum but you have to be willing to wade through the ton of arguments and opinions.

 

[nwbobber]

The PMV keeps pressure on the filter. It increases the dwell time of the air and thus makes it "cleaner".

There is a lot of great info in this forum but you have to be willing to wade through the ton of arguments and opinions.

Ah yes, but if I can come away with the reasons behind the arguments and opinions, perhaps I can become enlightened

 

[crpntr133]

Just remember that opinions are like butt holes...we all have one and everyone else's stinks.

 

[Isaac-1]

Let us know what happens, I have a 1978 Mako rebranded Purus that is very similar to the one you are looking at. Mine came with the older style filter and is mounted in a crash frame, it is rated at 3.2 CFM with a 230 volt motor, I have also retrofitted mine with an additional P0/P21 filter like yours has inline after the original as well as a Honda GC135 4HP gasoline motor for portable use. If I had it to do over again I would use a slightly larger motor, as the GC 135 starts bogging down when the pressure hits about 3,000 PSI (I have a couple of 3200 PSI tanks, blowoff is set at 3300 on the Purus from the factory). It seems every source gives a diffent figure for correct speed in RPM's the manual claims 1,600, other sources, nameplate, Bauer ads, etc. claim 1,800-2000.

Ike

 

[pescador775]

The back pressure valve does increase dwell time. However, that is not the purpose and dwell itself is of little consequence. By increasing pressure within the vessel the dew point is lowered. This is due to the fact that only a given quantity of water vapor can exist within a defined space. For example, at 100% humidity, the saturation point has been reached inside the vessel and no more moisture can be held in vapor phase. Thus, a doubling of pressure in the vessel causes a condition of 200% RH which results in immediate precipitation. A back pressure valve can raise internal press to almost 200 atmospheres with a corresponding rate of condensation inside the container. The other important considerations are the internals of the container. An increase of surface area speeds condensation. This is the reason for micronic elements which expose the moisture molecules to huge surface area. Also, there are the jet tubes which accellerate the air against a baffle wherein the gas immediately slows, transfers energy and loses its moisture load due to well known physical principles.

 

[Chariff]

Looking at the photos, this is a classic Purus-H. It was a decent personal compressor but Craig is correct, it does tend to collect water in the oil sump. Durability wise, you can look forward to frequent piston/sleeve changes, frequent oil changes, and frequent final valve failure. For that price i would walk. If you should happen to negotiate a more fair price such as US$500, then it could be worth the investment IF you only plan to use it as a personal compressor. BTW, parts are available for the Purus-H from NEW PARTS division of Lawrence Factor. 5000psi.com.

Chariff

 

[nwbobber]

Ok I found another opportunity, a bit more of a project but how about a ingersoll rand h10t2 10hp baldor from a fire dept. They were using it when it was taken out of service two years ago. 500$ I would have to replace the motor with gas-no 3ph at my house, what do y'all think?

 

[rcontrera]

$500!!! MAN ... Rings and gaskets will cost twice that!

Sounds like a fun project. Let us know how it turns out.

 

[nwbobber]

Oops. I wasn't quick enough. Some paintballer got it. Oh well, still on the hunt. I guess fire departments are getting homeland security grants to upgrade their scba systems, so maybe there will be another opportunity.