Refrigerant Compressor Pump as Air Compresor

[DLausche]

I've got a very old air compressor from my Dad that has always put out plenty of air. It leaks lots of oil though if I fill the oil plug to the top (in 2nd pic). The compressor is a very old V-4 refrigerant compressor model and I've got it powered with a 3/4 HP motor. I remember getting the compressor head used and very old when I was 16 and that was ~25 years ago.



Anyways, it pumps good, but leaks oil at the flywheel end crankshaft seal. It will leak oil at a good rate when it is pumping - enough to spray oil all over the place off of the flywheel. It stops leaking for the most part when the oil is below the crank seal level but I'm not sure if this is enough oil in the thing to prevent it from wearin out prematurely.



Question is, anyone know how much oil it should have? The plug in the 2nd pic here (see attached) is about even with middle of the crank if I fill it to the plug bottom. Any ideas on where I can go and find info on this pump is appreciated. I don't know what the brand/maker of the pump is but there is what appears to be a manufacturer marking on the pump that is an inverted trapezoid figure with an "L" in it. There are several other stampings on the pump but they appear to be casting #'s for the various pieces.



-Deon

 

[tgordon]

I would thinnk the oil level should be up at the one you fill through usually, but with this one the crank would be splahing the oil around and I would think you would get a lot of foaming in it.

 

[rbattelle]

What a cool pump!

Like tgordon says, you probably don't want the crank churning the oil. If it were me, I'd take the pump apart and measure for a new seal. It's probably a common size.

Ryan

 

[DLausche]

Yea, I think it is kinda a cool pump too but am not sure it is fixable. The oil seal is of a style I've never seen before. The bearing/bushing for the flywheel end is a full wet style as shown in the picture. The seal mechanism includes a spring with backing plate and a double rubber seal that the spiring thrusts against the end cap. It looks like there is a bushing in the removable end cap but it is not a bushing nor is it a seal since it is not close to tight on the crankshaft. The rubber on the seal looks definitely deteriorated and obviously this is part of the leak problem. Also, you can see from the first pic the end cap was cracked and welded and is now cracked again. It's hard to weld cast iron I know but I may have to give it a try.

If only I had purchased that CNC that I had my eye on a few months back... I wonder if there is any other way to find or make a new end cap that accepts a standard oil seal. Seems like it would work well if only I had a part or knew of where to go and ask.

-Deon

 

[rbattelle]

Are you sure none of those rubber seals measures out to a standard size? Seems like old stuff usually used standard size stuff.

As you point out, that end cap is exceptionally simple. Seems like it would be a piece of cake to make with some basic tools. You might even be able to buy an aluminum, steel, or iron blank that's close enough in size that you could take care of the rest of the piece with only a drill press. Maybe not.

Regarding welding the cast iron, is it possible to silver solder it instead? It looks like the cap isn't a highly stressed part, so you probably don't need the strength of a weld. Silver soldering would prevent the usual cracking issues associated with welding cast iron.

What kind of flow rates do you get from this pump? I mean, good?

Ryan

 

[DLausche]

I think I am onto the solution. I dug a bit deeper into the inner side of the end cap and discovered that the middle bushing was removable - and it was pressed into a rubber bushing as well. Once I got to this point I figured now I got something that a standard seal will fit so I decided to weld it and grind off the excess as best as possible. Took a micrometer to the shaft and it is exactly 3/4" and the inner bore of the end cap is exactly 1 3/8".



Where do I look for a standard oil seal that will fit these dimensions? That's something that has got to be available somewhere. Thanks.



-Deon



Oh yea, flow rates... I'm not really sure and don't really know how I would measure that. It is only on a small horizontal tank compressor with a 3/4 HP motor. I think it is woefully underpowered with the 3/4 and with a larger motor would probably put out good air volume but then would likely keep me busy running inside to reset the circuit breaker every few minutes.

 

[TJJEEPER]

Most bearing supply houses will have a good selection of seals.

 

[B.G. Smith]

That is a type-1, 3/4" mechanical seal, as stated above widely available. bg

 

[jwgary]

Go to SKF Seals to search for a seal that will work. You can find a vendor on their website that is in your area.

 

[rbattelle]

As usual, try McMaster-Carr too.

Nice welding job, Deon.

Ryan