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j.schaef

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Washington
I finally found something that isn't contained in the searchable archives here.

I'm Jeff, From the Everett area of WA, 35. Have a few acres, cars, and less shop space than I need.

Hoping a new shop is in my future, but it will be a while.


Maybe I can contribute somehow.

Here's what I need help with: Bought the biggest compressor I've ever seen, and have no idea what it is, or what I need in order to get it plumbed into my shop safely.

Would also like to get it running, and all 45 years of oil cleaned off of it.
 

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Dumber than lumber

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For starters we need to know how much you paid for that compressor.
You may be owed a”You ****”.
In any event : Welcome to the asylum!!
 
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J

j.schaef

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Washington
Thanks for the welcome everyone. Motor is 3 phase. 10 hp. I do not have 3ph at my house (yet) but am considering building an RPC for the compressor.

Doing a bit of research it appears to be a 1950s ish Chicago Pneumatic PB20 pump head. Estimating piston diameter and stroke length says it could make upwards of 125cfm.

I need to get it unloaded and cleaned up, see if I can make it work for me.

I am definitely owed a "you ****" for this. Got this compressor with a bunch of other cool things.

IR 30t 242 gas powered 40gal compressor

Airco Bumblebee 2 400a DC power supply with boom and about 1000' of leads and a sweet arc gouger.

Decent 7x12 horizontal bandsaw

2 fairly large drill presses

a flippin awesome old rivet press and about 500lbs of rivets and other brass hardware

About 2 tons of usable scrap steel (including old log truck cv shafts (holy holy **** these are huge)

About 5000' of nice goodyear air line. From 1/4" up to 1 1/4"

Two K size o2 tanks, and 2 135cf acetylene tanks, 1 210cf acetylene tank

Who knows what else is in there, those are just some of the things that I've come across so far.

Far as I can tell, the engine on the IR gas powered compressor cost more than I paid for everything. So I definitely ****.
 
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C

crankshaftdan II

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Feb 25, 2009
Messages
1,293
Location
Milwaukee, burbs.
j.schaef said:
I finally found something that isn't contained in the searchable archives here.

I'm Jeff, From the Everett area of WA, 35. Have a few acres, cars, and less shop space than I need.

Hoping a new shop is in my future, but it will be a while.


Maybe I can contribute somehow.

Here's what I need help with: Bought the biggest compressor I've ever seen, and have no idea what it is, or what I need in order to get it plumbed into my shop safely.

Would also like to get it running, and all 45 years of oil cleaned off of it.
Click to expand...

Nice catch on the CP compressor-they were originally mfgd. in Franklin, Pa. in the day. Parts might still be available thru the company in N.C./S.C. that bought them out-I've seen where they still make portable construction compressors currently-do a google search and should be able to find them, if required? Three phase would probably be the cheapest to operate if available. Sounds like you bought out a complete mfgr.??
 
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J

j.schaef

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Messages
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Location
Washington
Ha, fine then. I take it back.

I basically bought what was left of a logging repair company shop. The neighboring building bought the whole shooting match at auction, and just wanted to clear everything and use it for storage. I originally went to buy the overhead crane, but it was too much work to remove safely.
 
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larry_g

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Rule of thumb, 3.5 to 4 cfm per HP. So 10 hp then about 40cfm max.
Second assumption, RPC's don't do well with compressors unless oversized. Compressors are a high load so a bit of extra work is needed to make the generated leg deliver rated current. Study up before committing.

Understand your loads. A 10hp compressor is above what most single user shops can use.

lg
no neat sig line
 
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J

j.schaef

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Messages
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Washington
larry_g said:
Rule of thumb, 3.5 to 4 cfm per HP. So 10 hp then about 40cfm max.
Second assumption, RPC's don't do well with compressors unless oversized. Compressors are a high load so a bit of extra work is needed to make the generated leg deliver rated current. Study up before committing.

Understand your loads. A 10hp compressor is above what most single user shops can use.

lg
no neat sig line
Click to expand...

I've read this before here.

HP numbers don't dictate CFM. Thats a pretty crude generalization at best. This is a very large reciprocating compressor.

I understand how a RPC works, Have several 25hp motors I can choose from for a very reasonable price. Could get an RPC up and running for around $2-300 max.

Sure, it would be easier to just buy something plug and play, but what fun would that be? The easy way isn't always the best way.

Is this compressor more than I need currently? Yes. Does it open up some awesome potential for my shop to have some more rad tools if I decide to keep it? Yep. Huge sandblaster? No problem.

Estimating the piston size is around 5" in diameter. Maybe 6". Tough to tell, haven't pulled the thing apart yet.

Large side is at least 8" of stroke. Small side is at least 5" of stroke.

Lets just do some math here.

A = Piston Area (Square Inches)
S = Stroke (Inches)
C = Cycles per Minute
CFM (Cubic Feet per Minute) = (A x S x C) / 1728

Motor spins at 1760rpm. Large pulley is 24", small pulley is 9-10".

That means RPM is 660-730.


Feel free to do your own math :) Using these calculations, just the large piston alone can move close to 60CFM on its own.
 
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Old Man Roger

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j.schaef said:
I understand how a RPC works, Have several 25hp motors I can choose from for a very reasonable price. Could get an RPC up and running for around $2-300 max.
Click to expand...
This makes my previous post worthless, I thought it would cost a lot more than that.:beer:
With a compressor that big I think I would try to find more air operated equipment.:lol_hitti
 
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larry_g

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j.schaef

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larry_g said:
So by your way of thinking only the compressor head determines the CFM output? At what pressure?

https://www.engineeringtoolbox.com/horsepower-compressed-air-d_1363.html

Wander the above site for some information.

lg
no neat sig line
Click to expand...

Larry, seems you are a champion of word twisting.


No, what I am saying is HP numbers alone do not dictate the volume of air that a compressor can flow. I am no mathamagician, but even my feeble mind knows that there are far more variables at play than even the above linked site take into account. I am unsure how many CFM this compressor in its current configuration can flow.

I merely suggested that this pump head was capable of moving a lot of air.


j.schaef said:
"Chicago Pneumatic PB20 pump head. Estimating piston diameter and stroke length says it could make upwards of 125cfm"
Click to expand...

Could being the operative word.
 
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rlitman

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j.schaef said:
...No, what I am saying is HP numbers alone do not dictate the volume of air that a compressor can flow. I am no mathamagician, but even my feeble mind knows that there are far more variables at play than even the above linked site take into account...
Click to expand...

Actually, there are only two variables at play. The horsepower (which is not necessarily the motor HP, but should be pretty close to it if the pulley ratio is correct), and the number of stages in the pump. More stages help efficiency a bit.
 
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rlitman

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j.schaef said:
Le. Sigh.
Click to expand...

Look, you're looking at the problem backwards, which unnecessarily over-complicates things.

The energy to compress a volume of gas adiabatically is straightforward, and the bore, stroke and speed don't enter into the equation. Horsepower is a direct measurement of power, which is just energy over time. CFM, is a rate at which gas is compressed, and is directly associated with the power consumed.

So, if you drive your piston at a speed which produces 60CFM of output, you'll be consuming roughly 15HP.
 
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Shiftless

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East Bay SFO
rlitman said:
Look, you're looking at the problem backwards, which unnecessarily over-complicates things.

The energy to compress a volume of gas adiabatically is straightforward, and the bore, stroke and speed don't enter into the equation. Horsepower is a direct measurement of power, which is just energy over time. CFM, is a rate at which gas is compressed, and is directly associated with the power consumed.

So, if you drive your piston at a speed which produces 60CFM of output, you'll be consuming roughly 15HP.
Click to expand...

For a given horsepower, the CFM is greater if the output pressure is lower and vice versa.
 
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larry_g

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j.schaef said:
Larry, seems you are a champion of word twisting.


No, what I am saying is HP numbers alone do not dictate the volume of air that a compressor can flow. I am no mathamagician, but even my feeble mind knows that there are far more variables at play than even the above linked site take into account. I am unsure how many CFM this compressor in its current configuration can flow.

I merely suggested that this pump head was capable of moving a lot of air.




Could being the operative word.
Click to expand...

Since you didn't like the first link I gave you try this one, It has no math to confuse you.

http://www.aircompeq.com/ka.htm

lg
no neat sig line
 
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j.schaef

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Location
Washington
Right, there isn't a pump head listed there which is near as big as this one. This is the largest listed.

462TVX

Number of Cycles 4
Bore LP/HP 5.5 & 3
Stroke 5
HP Range 15, 20 & 25
Speed RPM
- 1750 Motor 522 / 775
PSI 60 to 200
Normal Free CFM 50 / 82


That is a solid 3" less stroke than the pump I've got.

Friendly bunch around here ;)
 
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larry_g

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Location
oregon
j.schaef said:
Right, there isn't a pump head listed there which is near as big as this one. This is the largest listed.

462TVX

Number of Cycles 4
Bore LP/HP 5.5 & 3
Stroke 5
HP Range 15, 20 & 25
Speed RPM
- 1750 Motor 522 / 775
PSI 60 to 200
Normal Free CFM 50 / 82


That is a solid 3" less stroke than the pump I've got.

Friendly bunch around here ;)
Click to expand...

So the biggest pump listed has a 15-25hp range and yours is bigger and you intend to run it with a 10hp motor and get more volume of air out of it,
it could make upwards of 125cfm?
Click to expand...
lg
no neat sig line
 
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J

j.schaef

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Messages
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Location
Washington
larry_g said:
So the biggest pump listed has a 15-25hp range and yours is bigger and you intend to run it with a 10hp motor and get more volume of air out of it,
lg
no neat sig line
Click to expand...

Are you daft?

Maybe reading comprehension isn't your strong suit haha.

What in your eyes does "could make upwards of 125cfm mean?

In my eyes, everything is fluid. I may use this pump head, with a different motor, on a different tank, in a different configuration. You've now told me twice that you don't think I need a compressor that large. Thanks for your opinion.
 
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