Power Equipment Forum banner

1 - 20 of 40 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
Hello all,

I am new to this forum and came here to hopefully receive some advice on an air compressor system that I would like to put together. I am a retired industrial electrician. I know quite a bit about electric motors and the electricity that runs them but have very little experience with the compressors themselves.

Many years ago, I obtained an old air compressor form this factory where I was working. It is a "Curtis" compressor that was manufactured by the Curtis Pneumatic Machinery Company in St. Louis. The compressor is on a heavy-duty base and it is a 2-cylinder model. I was told that it is a "high pressure" compressor.

The nameplate information on the compressor is as follows:
88 59-5158 Q108
Minimum 300 RPM
etc.

It has a 3-sheave pulley / flywheel on it that is approximately 14" in diameter. The compressor is not frozen up; the pulley / flywheel turns freely. I have a code vessel that I would like to use this compressor with. The vessel is 15" diameter and 36" long. It is rated at 200 PSI, at a maximum temperature of 650° F.

I guess my main question is: what size of a motor do I need for the operation of this compressor? I believe that the compressor originally had a 3 HP, 3-phase, 230V / 460V motor. I am not sure what the horsepower of the motor was.
Of course, I do not have 3-phase power here at my house, so I would be using a single-phase motor and would be
operating it from a 240-volt AC power source.

Thanks for any help with this!
 

·
Super Moderator
Joined
·
191 Posts
I found no information on the web about that model number, if that is what it is. A "high pressure," compressor is usually a two stage compressor. This is usually apparent if there is a considerable difference in the sizes of the two cylinders. The larger cylinder is a low pressure cylinder and the other smaller one is a high pressure cylinder. Two stage compressors can usually deliver around 200 psi, as opposed to standard compressors, which usually deliver about 150 psi. Without more specific information, the exact power requirements and the performance of that compressor would only be a wild guess. I'm guessing that the tank you are proposing to use would likely be inadequate in volume, and possibly in pressure, for that compressor.

Pictures would help. This site appears to possibly be a source for identifying it.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #3
I found no information on the web about that model number, if that is what it is. A "high pressure," compressor is usually a two stage compressor. This is usually apparent if there is a considerable difference in the sizes of the two cylinders. The larger cylinder is a low pressure cylinder and the other smaller one is a high pressure cylinder. Two stage compressors can usually deliver around 200 psi, as opposed to standard compressors, which usually deliver about 150 psi. Without more specific information, the exact power requirements and the performance of that compressor would only be a wild guess. I'm guessing that the tank you are proposing to use would likely be inadequate in volume, and possibly in pressure, for that compressor.

Pictures would help. This site appears to possibly be a source for identifying it.
The unit is in my basement. I will go down there and take a picture of it. I'm pretty sure that both
cylinders seem to be the same dimensions. But I will look more closely at that when I take the picture.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #4
The unit is in my basement. I will go down there and take a picture of it. I'm pretty sure that both
cylinders seem to be the same dimensions. But I will look more closely at that when I take the picture.
I found no information on the web about that model number, if that is what it is. A "high pressure," compressor is usually a two stage compressor. This is usually apparent if there is a considerable difference in the sizes of the two cylinders. The larger cylinder is a low pressure cylinder and the other smaller one is a high pressure cylinder. Two stage compressors can usually deliver around 200 psi, as opposed to standard compressors, which usually deliver about 150 psi. Without more specific information, the exact power requirements and the performance of that compressor would only be a wild guess. I'm guessing that the tank you are proposing to use would likely be inadequate in volume, and possibly in pressure, for that compressor.

Pictures would help. This site appears to possibly be a source for identifying it.
I went down in the basement and looked at it more closely. Apparently it is a "high pressure" compressor, because the two cylinders are of different sizes. I took a couple of pictures and will try to upload them to my message.

I looked in my McMaster-Carr catalog at code vessels and my tank is a 30-gallon size. I was thinking about using this tank, with a 175 PSI safety valve and a pressure switch that cuts out at 125 PSI. With the compressor being a "high pressure" unit, would it not just run until the 125 PSI cut-out point is reached?

Thanks.

Brad Anbro
Bluff City, Tennessee
8145
8146
 

·
Super Moderator
Joined
·
191 Posts
Those pressure settings sound like they should work, (assuming that the compressor has no problems) although you still don't know what size motor you need to run it. A couple of horsepower would be a good guess, if you select the right size primary pulley. Is that the vessel in question that I see in the background? You say that that is a "code vessel." Regardless of what it was originally rated at, things like rust, cracks, and time can compromise it, and you need to be sure it will safely handle the pressure. How long since it was hydrostatically tested?
 

·
Registered
Joined
·
1,213 Posts
3-sheave pulley ... hummmm
most of the time those are used on high hp setups like 25 hp and up...

they use a special bonded belt in some mission critical setups...

yea watch using old tanks...
they can rust on the inside ...
i like a 500 psi tank for a 250 psi shop setup...

that tank you wish to use looks to be low cfm tank...
if this is a larger setup I like the idea of 50 to 100 gallon tank....
 

·
Registered
Joined
·
244 Posts
Brad,

My guess this is a small two stage but I have no idea the model number or the exact condition of your pump. I would think a single phase 2HP motor would run this pump fine. The question is at what RPM? If you can figure the original motor rpm, HP and pulley size you can calculate the targeted pump rpm. I would get a two stage rated tank in any case (200 PSI working pressure). What is the use going to be for this project? tire inflator or production grinding?

RPM calculator:


Stephen


Hello all,

I am new to this forum and came here to hopefully receive some advice on an air compressor system that I would like to put together. I am a retired industrial electrician. I know quite a bit about electric motors and the electricity that runs them but have very little experience with the compressors themselves.

Many years ago, I obtained an old air compressor form this factory where I was working. It is a "Curtis" compressor that was manufactured by the Curtis Pneumatic Machinery Company in St. Louis. The compressor is on a heavy-duty base and it is a 2-cylinder model. I was told that it is a "high pressure" compressor.

The nameplate information on the compressor is as follows:
88 59-5158 Q108
Minimum 300 RPM
etc.

It has a 3-sheave pulley / flywheel on it that is approximately 14" in diameter. The compressor is not frozen up; the pulley / flywheel turns freely. I have a code vessel that I would like to use this compressor with. The vessel is 15" diameter and 36" long. It is rated at 200 PSI, at a maximum temperature of 650° F.

I guess my main question is: what size of a motor do I need for the operation of this compressor? I believe that the compressor originally had a 3 HP, 3-phase, 230V / 460V motor. I am not sure what the horsepower of the motor was.
Of course, I do not have 3-phase power here at my house, so I would be using a single-phase motor and would be
operating it from a 240-volt AC power source.

Thanks for any help with this!
 

·
Registered
Joined
·
244 Posts
Brad,

A couple of measurements would help too. How tall are those cylinders? what is the flywheel diameter? it's hard to tell the scale of the pump from a picture with nothing next to it to show it's relative size

Stephen
 

·
Registered
Joined
·
17 Posts
Discussion Starter #9
Hello all, I am replying to everyone who responded to my questions. I got the compressor from this company that I had worked at. We used to take "unauthorized" breaks and would crawl through this opening into a shallow "sub-basement. While crawling through the hole, we would occasionally run the compressor, by pushing in a manual starter. If I remember right, the motor was not all that "big," but it was a 3-pase motor and size for size, as 3-phase motor packs much more HP than a single-phase motor does. I do not have 3-phase here at my house, so I would have to go with a single-phase motor (or use a rotary phase converter, which I am not going to do).

I obtained the tank from a guy that I used to work with at a different company. He had a part-time "salvage business" on the side, in addition to his full-time job. He got the tank for me from a place that he was salvaging. The tank has always been stored inside and as I mentioned before, the specs on the tank are 200 PSI @ 650° F. Yes, that is the tank in the picture. I only plan on having a system pressure of 125 PSI. with the appropriate safety valve installed. Other than being very dirty, I believe that the tank is in good condition.

I would just like to end up with an air system, that I can run an air nozzle off of, inflating tires and also being able to use a die grinder once in a while.

Thanks to all...
 

·
Registered
Joined
·
1,213 Posts

·
Registered
Joined
·
244 Posts
Brad,

This would be a very guess based design but here goes:
searched for a similar compressor 3-5 HP


14 inch large pulley on pump
6.5 inch small pulley on 3 HP motor @1725 rpm
20 inch centers (or whatever)
Pump RPM = 800
 

·
Registered
Joined
·
244 Posts
Brad,

An incredibly expensive 3 groove motor pulley will not be necessary, a double groove will do fine.

Stephen
 

·
Registered
Joined
·
17 Posts
Discussion Starter #13
Brad,

This would be a very guess based design but here goes:
searched for a similar compressor 3-5 HP


14 inch large pulley on pump
6.5 inch small pulley on 3 HP motor @1725 rpm
20 inch centers (or whatever)
Pump RPM = 800

If I remember correctly, the 3-sheave pulley on the motor was about 2-1/2" diameter. I don't remember it being over 3" in diameter. That was over 27 years ago...
 

·
Registered
Joined
·
1,213 Posts
Brad,

An incredibly expensive 3 groove motor pulley will not be necessary, a double groove will do fine.

Stephen
that 3 groove has me questioning the hp required for the compressor..
most of the time they do not use them unless they need it...
it make have horrible run up power demand..
unless they did not have a good un loader on the system...

i wish the un loaders had a 2 second time delay on them to let the engine come up to speed before closing.
 

·
Registered
Joined
·
244 Posts
Iowagold,

The 3 pulley is way overkill for this application, you can drive 7.5 HP through a 6" diameter, single groove "B" pulley and it will transfer the power and not slip. With a 3 inch diameter single groove pulley you can drive up to 2 HP
8181


Stephen

that 3 groove has me questioning the hp required for the compressor..
most of the time they do not use them unless they need it...
it make have horrible run up power demand..
unless they did not have a good un loader on the system...

i wish the un loaders had a 2 second time delay on them to let the engine come up to speed before closing.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #16
Those pressure settings sound like they should work, (assuming that the compressor has no problems) although you still don't know what size motor you need to run it. A couple of horsepower would be a good guess, if you select the right size primary pulley. Is that the vessel in question that I see in the background? You say that that is a "code vessel." Regardless of what it was originally rated at, things like rust, cracks, and time can compromise it, and you need to be sure it will safely handle the pressure. How long since it was hydrostatically tested?
I just removed the 1/4" plug from the bottom of the tank. There was about a half & half mixture of oil and water in the bottom of the tank. I noticed that there was a pop-off valve installed on the tank. i removed it and cleaned it up, hoping to find some PSI info on it. The only marking I saw on it was "FIG 112" - whatever that means. Probably some number from the manufacturer of the valve, I am guessing.
 

·
Registered
Joined
·
244 Posts
Brad,

I would test this tank if you have any doubts about it's origin and condition. the video shows you how to accomplish this yourself.


Stephen
 

·
Registered
Joined
·
244 Posts
Brad,

If it were me I would test the tank, then build this for 145 or 175 PSI operation. You can do this because you have a 2 stage pump. If you had a single stage pump I would only set it to 140 PSI max.

Stephen
 

·
Registered
Joined
·
17 Posts
Discussion Starter #20
I just removed the 1/4" plug from the bottom of the tank. There was about a half & half mixture of oil and water in the bottom of the tank. I noticed that there was a pop-off valve installed on the tank. i removed it and cleaned it up, hoping to find some PSI info on it. The only marking I saw on it was "FIG 112" - whatever that means. Probably some number from the manufacturer of the valve, I am guessing.
I have another question! After I get done hydrostatically testing the tank to 200 PSI, what is the best method for cleaning the inside of the tank, practically speaking? Since there was both water and oil in the bottom of the tank, I was thinking about putting in a gallon or so of water-soluble cleaner and then rinsing it out with plenty of clean water. Then I thought that I'd get some charcoal briquets burning and then setting the charcoal under the tank, to allow the remaining water to evaporate. Then I would pour in a half gallon of (petroleum-based) oil and then drain that out. The oil would serve as a means of coating the bottom of the tank against further rust.

Is that a workable idea, or is there some better way to go about the cleaning & future rust prevention? Thanks...
 
1 - 20 of 40 Posts
Top