SpudFiles

I've seen lots of cheap hydraulic pumps and I was wondering whether it is possible to use them as air compressors ?

Possible, but the dead volume is likely too high to achieve much pressure. Perhaps if you fed it 500 PSI from a fridgy, you could reach a few thousand PSI, but otherwise, it may be too much.

There may be issuses with the seals and air.

Can I ask for a link to the pump?

like this proposal?

no not manual pumps...
http://en.wikipedia.org/wiki/Hydraulic_pump

I can get used ones for ~10-15$
http://allegro.pl/item1153240417_pompa_ ... chola.html

Hmmm... is the intention to achieve higher pressures than the fridgy can manage?

well these things are normally used with hydraulics (surprise surprise ) so they normally generate at least 150 bar

I don't think it will work. Hyd pumps are designed to pump a viscus liquid....air is much more illusive. Hyd pumps also self-lubricate with the oil they pump.

You could pump hydraulic fluid into a tank full of air, thereby presurizing the air.

@ranger
yeah but I'd have to drain the tank later and repeat the whole cycle... it would be a real PITA so I might as well build a simple pressure booster

@velocity3x
damn I was expecting that... but you are not 100% sure, right ?
I wonder if anyone can answer this question

Ranger wrote:You could pump hydraulic fluid into a tank full of air, thereby presurizing the air.

the compression ratio would be enormous, you would need to displace 150 cubic inches of air for every 1 cubic inch of air at 150bar.

If you need higher pressures, why not buy a simple AC compressor off of ebay? According to c11man and boyntonstu, they can reach up to 750 psi, and that should be more than enough pressure.
If you need more than that, my humble recommendation is to buy a SCUBA tank with hpa tank yoke adapter.

spudtyrrant wrote:The compression ratio would be enormous, you would need to displace 150 cubic inches of air for every 1 cubic inch of air at 150bar.

Only if you hadn't already pressurized the air tank - pressuring the tank to 9 atmospheres first would mean you required just a tenth of the compression ratio.

POLAND_SPUD wrote:@ranger
yeah but I'd have to drain the tank later and repeat the whole cycle... it would be a real PITA so I might as well build a simple pressure booster

It's not as if you don't have a hydraulic pump at your disposal.... Couple your tank with a few ball valves and you're in business. Don't think I'd do it unless I had the parts just lying around though....


As a statement in the general sense: Once upon a time I blew some things up. As in, 1.1C materials were involved. The explosion was unplanned and some hydraulic lines were ruptured.

The hydraulic pump - although well clear of the flames - died as a result of being run dry due to cut lines.

Of course, there are many types of hydraulic pumps out there, but at least in my case, running it on air killed it.

Mr.Sandman wrote:If you need higher pressures, why not buy a simple AC compressor off of ebay? According to c11man and boyntonstu, they can reach up to 750 psi, and that should be more than enough pressure.
If you need more than that, my humble recommendation is to buy a SCUBA tank with hpa tank yoke adapter.

We had a techie come by and look out our AC which was playing up, he said we have a 1.5k psi compressor in ours; and the new ones have 2k PSI

This^^ is reverse cycle heating cooling btw.

how about high pressure water pumps, at the market on sunday there was 96 bar one for 10 bucks?