Compressor Project

Having obtained a 12 metre pump up mast for hanging antennas on I decided I needed a quieter compressor than the B&Q one I bought a few years ago.  I had heard people talking about converting fridge compressors and, knowing how quiet they are, thought it would be a great idea.

WARNING - DO NOT ATTEMPT THIS

This is a record of how I converted an old fridge compressor unit and is presented here purely for interest.  I do not advise or encourage anyone to follow what I have done. I strongly advise against carrying out such a conversion.   Refrigerator compressors and their associated pipe work contain refrigerant gases which can be under high pressure. High pressure gas is dangerous.  In addition to the high pressure some of these gases can be very dangerous to your health especially if inhaled.  The only people who should carry out this type of work are competent refrigeration engineers.

The objective was to produce a compressor which was quiet to run and would supply about 20 psi for a SCAM 12 pump up mast.  It needed to look after itself and switch on as seldom as possible.  The pressure switch to operate the motor cuts in at 30 psi and cuts out at 90 psi.  The left hand red valve connects to the reservoir gas bottle at 90 psi.  The middle red valve can be used for either connecting to the noisy higher volume compressor, in case extra air volume is required, or for supplying 90 psi to something else.  The right hand black valve is the regulated supply to the mast.

Here is the compressor as removed from the fridge.	This is what it looks like when the top cover has been removed.  This required over an hour with a hand grinder.	The compressor container contains oil for lubrication purposes which is normally contained within the closed loop system	As the new use will be an open system I required a method of keeping the oil level topped up so a combined filler and dip stick was added.
This is base for the compressor project.  After having been squared up to size Pete is drilling the compressor mounting bolt holes.	Air reservoir	Compressor fitted to base main pressure gauge and control valves fitted.	Regulator and oil mist lubricator added.
Mounting block for pressure switch.	Angle fixing bracket for pressure switch.	Squaring up the mounting block.	Pressure switch mounted to block.
Pete tapping the fixing holes for the mounting block.	Pressure switch mounted and interconnecting pipe work fitted.	Pressure test and leak testing.	Oil mist lubricator removed because it leaked like a sieve. Note the can of leak indicator to the right which I just could not get on with.  Reverted to soapy water and a brush.
		These are mighty little machines.  During testing I accidently fitted the non return valve the wrong way and switched on the compressor.  All the pipe work uses push fittings which I think are ok up to about 150psi.  Well, after about 30 seconds the non return valve push connector parted company with a very impressive BANG!	If we ever get to move I'll report on how well this little machine works - or not!
Compressor unit completed and tested.	And with the sides and carrying handle fitted.