Questions about compressor pumps

[Shoreline_]

So I was cleaning out my storage garage and my neighbor that owns the other side gave me some stuff from his business. Part of that was these two air compressor pumps and the tank. I don't know anything about them but they seem to have an oil pump on the front? They look small. Any info? I don't know what to do with them yet. They look too nice to toss. The tank says "Westinghouse" and looks wicked thicc.

 

[g13092]

They both look like the 210 quincy I recently started working on. Yes, they have an oil pump. You have a dual control on the left on and both have unloader towers. The left one is missing the hydraulic valve that triggers the unloaders when the oil pressure rises. The right one seems to have that valve, but is missing plumbing to the towers. Look on the left side of each, there should be a plaque with the model. Mine seems to run around 5cfm at 700 rpm. My pump seems to date to the late 60s. I'd hydrotest that tank before using it. plenty of threads in that around here.

 

[Shoreline_]

Okay thanks. I found some literature about them but nothing mentioned about that dual run. The unloader idea looks cool. But only one style unloader is shown in the literature. Looks like max rpm is 900. How much more cfm is that? 1? lol.

 

[g13092]

Okay thanks. I found some literature about them but nothing mentioned about that dual run. The unloader idea looks cool. But only one style unloader is shown in the literature. Looks like max rpm is 900. How much more cfm is that? 1? lol.

I've never seen the speed vs cfm curve for the 210, but I don't imagine it's much extra from 750 to 900. I just timed a tank fill. This thread is pretty good. https://www.garagejournal.com/forum/threads/quincy-210-air-compressor.366850/post-6644131
Look through it all, because the OP machine was not plumbed right. There's a few links to literature in there.

 

[oldmachinenut]

It looks like a pneumatic control air source for a school, hospital, or other large building.

 

[Shoreline_]

Well I was thinking of running both pumps at the same time with a motor in the middle. Any reason I can't? Like if I have a 2hp and 1hp can drive each one, can't i use that motor?

 

[micromind]

Well I was thinking of running both pumps at the same time with a motor in the middle. Any reason I can't? Like if I have a 2hp and 1hp can drive each one, can't i use that motor?

Belt tension could be tricky.

But yes, it'd work.

 

[Shoreline_]

I was looking at it today quickly. Is there a benefit of the unloader working off of oil pressure? Why can't I just work them off a pressure switch like everyone else?

 

[The Cobbler]

Well I was thinking of running both pumps at the same time with a motor in the middle. Any reason I can't? Like if I have a 2hp and 1hp can drive each one, can't i use that motor?

you could . you would probably have to fab up something for belt tension, as mentioned previous . and probably a double v pulley , offsetting one pump to line up to one of the grooves. .
I have very little knowledge on oil pressure unloaders, all I've ever had is pressure switch activated. I don't know the idiosyncrasy differences

 

[micromind]

For belt tension, you could remove both pumps and cut slots where the mounting holes are.

You could do it with only one pump but it'd be harder to get both belts tensioned properly.

 

[Shoreline_]

Tonight I'll tinker with it some more. I don't have the electrical circuit for 2hp. I can run like 1hp safely. Soooo I wonder what I can do to still run both pumps.

 

[micromind]

1HP will produce roughly the same air output using one pump or two.

If you use one pump, you have a spare when it burns up. Using both pumps might result in longer life but they'll both fail at about the same time.

 

[Shoreline_]

1HP will produce roughly the same air output using one pump or two.

If you use one pump, you have a spare when it burns up. Using both pumps might result in longer life but they'll both fail at about the same time.

According to some random online calculator, If I use 2 pumps at 900 rpm with 1hp my max psi is like 40 before I'm into too much amperage. This way I'm still in the rated RPM and amperage. I don't know what will burn up. Can you expound on that?

 

[micromind]

I depends on how much pressure you need. 40PSI won't run an air tool, like an impact wrench.

By 'burn up', I meant the pumps. Eventually, like everything that moves, it will wear out and become useless.

I sounds like running both pumps with one 1HP motor won't work, unless 40PSI is all you need.

If you run the pumps at a slower RPM, they'll need less HP but there's a low limit to pump RPM. Usually around 400 - 450 or so.

 

[Shoreline_]

I depends on how much pressure you need. 40PSI won't run an air tool, like an impact wrench.

By 'burn up', I meant the pumps. Eventually, like everything that moves, it will wear out and become useless.

I sounds like running both pumps with one 1HP motor won't work, unless 40PSI is all you need.

If you run the pumps at a slower RPM, they'll need less HP but there's a low limit to pump RPM. Usually around 400 - 450 or so.

Oh I don't think they will burn up. Pressure lubricated and all cast iron? It'll probably last longer than a 53 series Detroit. Rod ratio is around 2:1 and it looks around a 4-4.5" rod which is like a 15* rod angle and at 900 rpm we're talking about 500 fpm piston speed. I looked at the rings online. Super chonky cast iron.

But I am thinking critically about how to run it. I've been reading about compressors and how they work. Doing some terrible math, I found at 150 psi and 900 rpm is only like 3/4hp but 3.5 cfm. That is a single cylinder of the 4 making air.

 

[g13092]

I was looking at it today quickly. Is there a benefit of the unloader working off of oil pressure? Why can't I just work them off a pressure switch like everyone else?

The unloader tower runs off air but it is switched by oil pressure. The pump can ramp up to speed with the intake closed until there's some oil psi. You can use a pressure/control switch unloader on the outlet side instead, if you have a check valve at the tank. I'm not sure one is better than the other, but I get the impression the control switch unloader is cheaper. Maybe others can shed some additional light.

 

[Shoreline_]

Little update-

I have the motor mounted for now to run one pump. Im gonna grab a belt and pressure switch this week.