Can fridge compressers pump air?

[neutron7]

Fridge compressors are a lort quieter than regular compressors and quite easy to come by
i was wondering if i could use one for an air compressor because my compressor is so noisy it is really annoying and i can not use it late at night.
The freon stuff inside is a gas at one point, im not sure if its a liquid or a gas when it passes through the compressor. if its a gas it ought to work, the other question is how much pressure it can produce, it needs to do 80-100 PSI

[seventenths]

Yes it can and has been done... in excess of 100 psi.
I know a couple of people using these units for vacuum pumps (laminates) as well. Quite a bit of info can be found via the usual suspects (google et al)

7/10

[MJL21193]

Hi,
Pressure is one thing, airflow is another. A regular air compressor has a CFM rating (cubic feet/minute volume). I would imagine that for a fridge compressor, this would be very low.

[Magura]

Originally posted by MJL21193
Hi,
Pressure is one thing, airflow is another. A regular air compressor has a CFM rating (cubic feet/minute volume). I would imagine that for a fridge compressor, this would be very low.

This is true. I have once made such an installation due to the same reasons as Neutron7 described above. The cure is a fairly big tank.
I got around by taking the control unit and the tank from a dead compressor.

Magura

[neutron7]

thats a good thing, my compressor and tank are separate units. so all i probably need is a pressure controlled switch to turn it on when the pressure is below a certain level,

the tank has a gauge on it as well.

I have a friend who is a scrapper, ill ask him to look out for a nice big one!

most of the things i use air for do not use a great deal of CFM.

if i want to paint or something that needs a lot of air ill just use the noisy one.

[Circlotron]

In a fridge, doesn't the oil circulate around the loop with the refrigerant? It does with car air conditioners I think.

[OzMikeH]

Not sure about air considioning but for domestic refrigeration the oil should not circulate around. After laying a fridge down for transport it should always be left upright for an hour before applying power. If any oil does get into the pump's intake it will "hydraulic" the compressor and burn the motor out.
The pump inside the pumpkin does sit in a bath of oil, if too much oil is lost the pump will quickly fail.

CFM rating of a fridge compressor is very, very small. (CFM = cubic feet mer minute) You need about 12 CFM for a pneumatic drill and about 17 for spraypainting. The power required to run both types of compressors should give a rough indication of the capacity. About 150-200 watts versus 1500-2400 watts.

Check the sticker on the refrigeration system before "liberating" the compressor. R200 is flammable. R12 and R22 are chloroflurocarbons and should not be released to atmosphere.

Automotive air conditioning compressors with some modifications make excellent air compressors.

[AndrewT]

Hi,
A friend built one from a fridge compressor and a propane tank.
The normal pressure in a propane tank is about 80psi so 100psi is an overload.

But if you fill the propane tank with water and ensure all the air is removed then couple up a test gauge and water pump (something like a grease gun action would do). You can do a relatively safe HYDRAULIC TEST. Take this to 50% more than your expected MAXIMUM working pressure. If you want 100psi as a normal working pressure then your regulator controlling the on/off of the compressor will be set to 105 to 110psi.
There will be a safety relief valve set point, another 5 to 10psi above this. Your maximum working pressure is the +tolerance on the safety relief. You have a total of 105 + [5 to 10] + [5 to 10] +% = about 120 to 130psi = Hydraulic test pressure of about 180psi.
Repeat this safety test at about yearly intervals and if the tank ever gets a knock.

.DO NOT air pressure test the tank.
You could kill yourself and anyone in the vicinity.

[Ron E]

A cautionary tale:

A friend was using a home modified compressor (commercial ~50gallon tank) that had worked well for quite some time. Air when compressed liberates water and even when drained regularly via the valve at the bottom of the tank there is risk of corrosion. Anyway, my friend rested his hand on the tank and bent over to check the pressure (to shut it off before the limit switch did - probably because of noise ) and the thing exploded. It burst apart at the (corroded) welds, blew him backwards and crushed all the bones in his wrist and broke a few metacarpals, permanently limiting his functionality. I can only imagine the pain, some of which he still experiences, I am sure.

[theAnonymous1]

I remember when I used to live with my Grandfather he had a setup in the garage that used four refrigeration compressors. It worked quite well and he said the setup had been running longer than I had been alive.

I would assume he used four of them for a higher cfm.