which compressor

Are automotive air con compressors compressing gas or liquid?

The usual advice is to run the air con on the car for about 5 minutes each week to keep the seals lubricated. That suggests liquid rather than gas. Or maybe the refrigerant is below its critical temperature, and when compressed it changes to liquid, and that is what lubricates the seals.

Anyone to enlighten us?

Howard

My car troubles relate to my air con pump...

The bearings collapsed and it took out the alternator belt.

Got a s/h pump and took it to be fitted and the aircon regassed and... wrong pump.

Next try somehow I had tuesday in my diary and the garage had monday...

Hopefully third time lucky, but I do have a spare pump now...

Neil

P.S I can't see how it would work without a clutch

P.P.S. they work at scary high pressures.

P.P.P.S. I think 5HP is about right, I think they add about 5% to petrol consumption.

(PS) Dunno about removing the clutch and replacing with a pulley, but not an insuperable problem?

(PPS) The recharge dispenser attachment indicates only 2.75 Bar (40 psi). It is only a matter of boiling a low boiling point liquid and condensing it.

(PPPS) Long ago, 4HP was quoted so 5, nowadays, seems reasonable - but that is at engine and pulley multiplier speeds. Only 5% for a ~100 HP engine? Common rail diesel injection pump pressures are scary!

Not all pumps will be the same capacity - I expect the one I have is for a fairly large vehicle - but I don’t know for certain. Perhaps the pump speed is altered for more or less cooling?

They all have lubricant in them - whether automotive or fridge type. I know of people recharging a freezer compressor with propane. It worked. The lubricant should remain in the pump if they leak on the gas side, but most automotive pumps are emptied and recharged with lube and refigerant, I believe.

.

This should help, Howard: **LINK**

http://www.airconcars.com/html/how_it_works.html

MichaelG.

Just bought a used JUN-AIR JUNIOR MODEL . Not arrived yet but looks almost new

All refrigerant comoressors, electric or mechanical pump vapour, if they pump liquid they very quickly destroy tgeir valves or con-rods.

It is the oil mist mixing with the refrigerant that provides the lubrication to the seals etc.