Working out CFM

[chapel gate]

We have a vary large, very old compressor. Anyone know a simple way of working out its CFM?

 

[clivehorridge]

I imagine you’d have to know it’s displacement, then rpm, and the rest is a bit of maths... no?

 

[moggy1968]

Theres usually a manufacturers plate somewhere with it on, or some equivalent measurement like ltrs per min

 

[chapel gate]

I imagine you’d have to know it’s displacement, then rpm, and the rest is a bit of maths... no?

Maths ain't my strong point Clive..

Heres the old girl.
Got it working again a few years ago now by replacing a broken con rod.
It's about time I revisited it.

 

[StarCruiser]

Looks like a two stage unit. Post up a pic of that label on the compressor. I can’t quite read the name, looks like Tecalemit but I’m not aware they did compressors.
I used to have an intake filter that would probably fit that. No idea where it might be (if I’ve still got it) but if I find it you can have it.

 

[chapel gate]

Yes. It's a tecalemit.

I'll get a close up of that plate this morning.

Cheers. Would you like a brass fire extinguisher?

 

[chapel gate]

Here you go.

 

[StarCruiser]

Yes. It's a tecalemit.

I'll get a close up of that plate this morning.

Cheers. Would you like a brass fire extinguisher?

If I get any likelihood of brass fires, I might take you up on that.

 

[StarCruiser]

Why guess from that plate is a 1972 model 10.5 CFM but that’s an initial guess that just looks right. I’ll see if I can put any meat on those bones.

 

[StarCruiser]

Have you tried emailing Tecalemit service?
[email protected]

 

[frank rabbets]

Got any gold ones ?lol.

 

[flint]

Not sure, but on this page it mentions the IR T30 being used on the Tecalemits of that era. A search on the IR link mentioned might help.
https://www.mig-welding.co.uk/forum/threads/tecalemit-compressor.23436/

 

[frank rabbets]

Mike you can time how long it takes to blow up a bin liner with it until you have a rough cube then work out the volume.

 

[StarCruiser]

Better still, work out the volume of the receiver and time how long it takes to fill it. If you then average it from 0 to 100psi, (or would that be 14 to 100 psi?), the result you’ll get will be the CFM at 50 psi. In other words it will probably pump more at atmosphere than it does at 100 psi, and decrease over a linear scale. If that makes sense.

 

[chapel gate]

Got any gold ones ?lol.

They Polish up really nice frank, they almost look gold.
Great for de greasing engines too...

Not sure, but on this page it mentions the IR T30 being used on the Tecalemits of that era. A search on the IR link mentioned might help.
https://www.mig-welding.co.uk/forum/threads/tecalemit-compressor.23436/

Thanks flint. Some of the info on that thread may explain why I had to replace the con rod in the first place.

Better still, work out the volume of the receiver and time how long it takes to fill it. If you then average it from 0 to 100psi, (or would that be 14 to 100 psi?), the result you’ll get will be the CFM at 50 psi. In other words it will probably pump more at atmosphere than it does at 100 psi, and decrease over a linear scale. If that makes sense.

Jaysus rich! I think I'll contact Tecalemit on Monday like you suggest..

 

[frank rabbets]

Richard I was wondering how they spec the compressors in CFM as the compressors will be less efficient the higher the pressure pumped in to.

 

[StarCruiser]

Richard I was wondering how they spec the compressors in CFM as the compressors will be less efficient the higher the pressure pumped in to.

Exactly what I was getting at in my last post. In free air they will pump slightly more than at, say, 100 psi. Hence timing the pumping from zero to 100 psi would give the CFM at exactly half the difference. Ie at 50 psi.

 

[chapel gate]

Ah, I'm with you now.
Rang them. 10.2 cfm.

Take a bow rich.

 

[StarCruiser]

Ah, I'm with you now.
Rang them. 10.2 cfm.

Take a bow rich.

Probably 10.5 at atmosphere and 10.2 at 100 psi or whatever it’s rated pressure is.

Great to have another helpful UK company happy to help on something nearly 50 years old.

 

[chapel gate]

Probably 10.5 at atmosphere and 10.2 at 100 psi or whatever it’s rated pressure is.

Great to have another helpful UK company happy to help on something nearly 50 years old.

Yes. He was more than willing to help.