identify old compressor
- Thread starter TxRzrBk
- Start date
kams1973
ALLIANCE MEMBER
Can't tell for sure, but it looks like a United States Air Compressor Co. pump.
kams1973
ALLIANCE MEMBER
You can still get parts from Collins Equipment. They list specs on their site. Check out the link below.
http://www.collinsequip.com/usair.shtml
http://www.collinsequip.com/usair.shtml
94yj
Well-known member
any way to get a closer picture of the pump
I'll am going to go look at it tomorrow. The guy who owns it said he thinks it is from the 30's and also said he can't find any markings on it. He said it works fine but it does not fill as quickly as it once did, I am guessing given it's age the reeds are probably shot. I can get a good deal on it so if the tank is solid i'll probably just buy it and hope for the best. The only other info I have on it is that apparently the seam on the tank is riveted, I have not seen one like this but the gentleman says it is original and not a repair job.
Edit: attaching a slightly enlarged/enhanced version of the original picture
Edit: attaching a slightly enlarged/enhanced version of the original picture
Attachments
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Zrexxer
Well-known member
That's an SMD compressor.
Brought to you by the fine folks at Screaming Metal Deathtrap, Inc.
Brought to you by the fine folks at Screaming Metal Deathtrap, Inc.
Very helpful...thanks
Zrexxer
Well-known member
OK, since the hint was lost on you... riveted tanks like that have not been used in a very long time, and without knowing its real condition, could very likely be a seriously hazardous piece of the equation. Taking the seller's word for it or buying it and "hope for the best" is not the same as knowing. Add to that the fact that by the seller's admission, the pump isn't working correctly, that you don't know what make or model it is, and even if it's not something terminal, you don't know if the parts you need are available.
How many problems do you want to buy?
Point taken but given the price and age I don't expect anything pristine . I can handle listening to it and tapping on the tank and making a judgment call as to if it is worth the time and effort. If I miss something serious, very worst case the scrap metal is likely worth the asking price, best case with a little elbow grease I have a quiet compressor that chugs along at 600 rpm and produces plenty of air for less than the cost of a tank of gas.
Back to my original question...Anyone have any insight as to if it is a us compressor ? Looks very similar to a MK series to me.
PBCampbell
Well-known member
In your first post picture that tank strongly resembles an old water heater tank. I'm unsure if that would pose a significant health risk but it's something to be cautious about.
stratman977
Well-known member
Just so you know that in the time frame that this compressor was built was in the early days of pressure tank design standards. In the early part of the 1900's lots of boilers were exploding and killing people. The ASME Boiler and Pressure Vessel code came out to create standards for designing these tanks to prevent these explosions. That tank is definately not an ASME tank.
Even if the tank hasn't rusted, the metal may be near the end of its fatigue life and could let go. Do yourself a favor and put that pump and motor on a newer tank. People here aren't yanking your chain about it being a death trap, they are trying to give you a decent piece of advice.
Even if the tank hasn't rusted, the metal may be near the end of its fatigue life and could let go. Do yourself a favor and put that pump and motor on a newer tank. People here aren't yanking your chain about it being a death trap, they are trying to give you a decent piece of advice.
Fretters
Well-known member
Boilers are vastly different to what is a relatively low pressure vessel by comparison. Any type of container can explode if corrosion has set in or if it is run above its rating. Same rule applies with any pressure vessel. Have it pressure tested to verify reliability if required. Personally, I'd run that without a second thought after giving it a once over. It has lasted all these years.
There's sensible caution and then there's just plain old paranoia. Seems the latter is coming to the fore in this thread.
There's sensible caution and then there's just plain old paranoia. Seems the latter is coming to the fore in this thread.
stratman977
Well-known member
This is my point exactly. These things have a usable life. Pressure cycling from 0 psi to 100 psi over the life of the tank wears the metal out, its called fatigue. Eventually it will crack due to fatigue.
And to your point about boilers, its not much different in term of design. Yes boilers have more pressure but they also have thicker walls. The run hotter but they also have thicker steel to account for that. Pressure is pressure.
Its all about risk. Google air compressor tank failures to decide for yourself if its worth the risk.
I have tried to acknowledge the potential risk and redirect this thread to helping me figure out the make/model of the compressor. The compressor has been in use for roughly 75-80 years, it wasn't sitting in the corner of a barn rusting it was actively being used in a garage shop, I don't think I need to fear it but use a little common sense...GOT IT!
YES - I will use caution, Yes - I will Hydro test it
YES - I will use caution, Yes - I will Hydro test it
MacMcMacmac
Well-known member
It's a United States Air Compressor Co. MK pump on an old tank which likely carried a Curtis pump when it was built.
Attaching two pictures
1) a parts diagram for the United States Air Compressor MK series
2) a Picture of the head of the compressor in question
Notice the connection between the two cylinders, on the MK series it is opposite
of the air intake. In the picture of the compressor the connection between the two cylinders is behind the compressor pulley.
Unless there are additional variations of the MK series that I have not seen I don't think it is a match.
Attachments
MacMcMacmac
Well-known member
http://www.ebay.com/itm/United-Stat...404?pt=LH_DefaultDomain_0&hash=item27cc7d2a2c
This MK4700 pump sure looks like a dead-ringer for yours, at least from what I see of the cylinder head. Not the same model, but I think this narrows it down to the manufacturer anyway.
I am a bit embarrassed after introducing myself as a compressor tech to say I had not heard of US Air Compressors before looking through this site. I guess you should stay modest no matter how long you've been at something!
This MK4700 pump sure looks like a dead-ringer for yours, at least from what I see of the cylinder head. Not the same model, but I think this narrows it down to the manufacturer anyway.
I am a bit embarrassed after introducing myself as a compressor tech to say I had not heard of US Air Compressors before looking through this site. I guess you should stay modest no matter how long you've been at something!
Your right, that is for sure a match, I appreciate it. On mine there is nothing connected to the centrifugal unloader, I assume that has been disabled in favor of a check valve?
I'll have to get in touch with Collins Equipment and see if I can get parts, the compressor works reasonably well but I think the rings are pretty worn on the smaller of the two cylinders, I pulled the valves and a small amount of oil had gotten into the exhaust side of the smaller cylinder. The valve springs also seem to be pretty weak and one of them is on it's last legs. Has anyone figured out an alternative for the stock valve springs?
I'll have to get in touch with Collins Equipment and see if I can get parts, the compressor works reasonably well but I think the rings are pretty worn on the smaller of the two cylinders, I pulled the valves and a small amount of oil had gotten into the exhaust side of the smaller cylinder. The valve springs also seem to be pretty weak and one of them is on it's last legs. Has anyone figured out an alternative for the stock valve springs?
This may have been said already, but the compressor & motor base are obviously from another application, probably an old refrigeration compressor or generator base.
Compressed air is to be treated with great respect. Do a search on the net for photos of failed air tanks. The only thing more impressive is flywheel failures!
Only the oldest guys would be able to tell you what that tank was for originally.
The motor and probably the pump are gems and well worth cleaning up and rebuilding if necessary. The motor is probably a repulsion induction type, which are no longer made and getting harder and harder to find as more get scrapped for the copper every day.
Some old tanks are so massively built that failure is probably "not an option", but rust and metal fatigue are unknowns. If it has large enough plugs you could remove them and inspect the interior, but just as in old rivetted boilers, the deterioration and failure usually occurs around the seams where it is not easy to detect. You could cut out a round on one end and clean it out, have it properly welded back together, hydro-tested and all that, but is it worth the trouble when it's not an original set up anyway?
Get a retired upright 125gal/400lb propane tank if you want a tank with heavy walls, built to withstand a lot of pressure. I wouldn't use that one unless it was in a field or buried in the ground. People get lazy or stupid: I bought a 80 gal unit made a few years ago recently and found there was about 2 gal. of water in the tank, and this had been used in detail shop where you would think they would have some idea of basic maintenance!
Compressed air is to be treated with great respect. Do a search on the net for photos of failed air tanks. The only thing more impressive is flywheel failures!
Only the oldest guys would be able to tell you what that tank was for originally.
The motor and probably the pump are gems and well worth cleaning up and rebuilding if necessary. The motor is probably a repulsion induction type, which are no longer made and getting harder and harder to find as more get scrapped for the copper every day.
Some old tanks are so massively built that failure is probably "not an option", but rust and metal fatigue are unknowns. If it has large enough plugs you could remove them and inspect the interior, but just as in old rivetted boilers, the deterioration and failure usually occurs around the seams where it is not easy to detect. You could cut out a round on one end and clean it out, have it properly welded back together, hydro-tested and all that, but is it worth the trouble when it's not an original set up anyway?
Get a retired upright 125gal/400lb propane tank if you want a tank with heavy walls, built to withstand a lot of pressure. I wouldn't use that one unless it was in a field or buried in the ground. People get lazy or stupid: I bought a 80 gal unit made a few years ago recently and found there was about 2 gal. of water in the tank, and this had been used in detail shop where you would think they would have some idea of basic maintenance!
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The tank and base are from an old Curtis compressor, if you look up 20s-30s Curtis compressors you will see an identical tank. The tank is very heavy duty, it weighs 3x what a newer tank of similar size would wiegh. That said I dont think I will be using the tank, when I opened the petcock it had at least a gallon of rust water in the bottom of it and its just going to be more trouble than its worth to make sure its sound, it will probably end up getting scrapped or turned into a smoker.
I have been keeping my eye open for used air tanks, problem being that most people Dont drain them so they are all fairly suspect. I hadn't thought about the propane tank route, its a good idea, only draw back being that I was thinking of going with a vertical setup.
As for the motor, it is a repulsion induction
I have been keeping my eye open for used air tanks, problem being that most people Dont drain them so they are all fairly suspect. I hadn't thought about the propane tank route, its a good idea, only draw back being that I was thinking of going with a vertical setup.
As for the motor, it is a repulsion induction