PTO Air Compresser

[diggerman]

I was thinking of building one and wanted to know if anyone here has built one.

 

[srjones]

I haven't build one, BUT....

I've given it some thought as too how I would build one. As far as I can tell, there are basically two different types.

1. The ones that connect directly to the splined shaft like these PIUSI - Fluid Handling Technology

2. The ones that the are much more detached and are more of a separated unit, like these. Power Take-Off Compressors Similar to PTO generators. A variation would be to make the platform mounted on a 3PH

To build a PTO driven compressor, I would opt for the 2nd type. This would let me use the biggest compressor I could find that would actually take adantage of the extra HP from the PTO. Also, mount storage tanks and additional things like regulators, oilers, dryers, etc. right on the trailer.

I would need to make sure the the PTO rpm doesn't exceed the acceptable speed of the compressor. A direct coupling to the compressor would be my first choice since I wouldn't need to mess around with pulleys and belts.

My main purpose for have a mobile supply of compressed air would be something like this:

United States Patent: 6776242

It's just no fun driving fence posts...especially in August. And by the time I'm ready to build one, I'm sure the patent would have expired

 

[RonMar]

I have been thinking about one so I can have a high volume source for sandblasting. You can get 2 cylinder compressor assemblies from Harborfreight for $70 when on sale. Thru a pully and flywheel asembly, you could probably drive 2 of these off a typical CUT PTO. The only issue I see with homebuilding one is automatically controlling the resovoir pressure like the electrics do(by shutting off when peak pressure is reached). Since uncoupling the compressor from the PTO automatically would be difficult, I guess some sort of diverter to send the compressor output into a muffler when the tank is full would be the way to go.

 

[shvl73]

You could buy one of the valves that the gas powered jobsite compressors have. Emglo had some sort of by-pass valve that would relieve pressure from the pump until the pressure switch fell below a certain psi.

 

[TOMDUALLY]

You could use an electric clutch on your compressors, The ones simular as the air condition on a car uses just run the wires thru the pressure switch.

 

[638]

A long time ago I built an air comrressor using a compressor out of a wrecked bus. It was a 3 cylinder job and I hooked it up to a very old 2 cylinder Leroy engine. Used the air tanks off of the same bus and had all the air I needed to spray paint with. If you have any junk yards around that have wrecked trucks in them you might want to look at that angle. This was about 1970 and I had less than $25 in the whole rig.

Ron

 

[joelaudi]

I think you will need to get yourself an air compressor that has unloaders built in. They are called constant speed type. They unload the intake valves when the tank pressure reaches the correct psi, then the compressor just spins without making any air. If you devert the air into a muffler that would be a big waste of HP. A 5to 7 HP compressor would most likly be fine for sandblasting. Most heavy duty compressors turn at 600 to 800 RPM so a direct pto drive at 540 would work. You just have to be sure that the rotations are correct [look on the flywheels they have a large arrow casted on it to show the rotation]

 

[diggerman]

I have a couple of old air compressor without motors that I thinking of using .I also have an old air cylinder that I thought I could use to turn off the compressor at around 100psi and back on when the pressure drops .This cylinder would have a line from the tank so that when the pressure got around 100psi the cylinder would disengage the belt drive by loosening the tension pulley.I will also add a relief valve for safety .

 

[Pooh_Bear]

I added an air compressor to my pickup years ago.
I had a 1970 Ford F350 dump truck.
I had an air tank mounted to the frame behind the cab. But it just had an
air valve on it for like airing up tires. Used a tire chuck to fill it up.
Blew up the motor in the truck one year and had to get another one.
Got one from a 79 Lincoln Mark V and it had an A/C compressor on it.
I plumbed the A/C compressor into the tank and up into the cab.
Put a pressure guage in the cab where I could see it.
Wired the electric clutch thru a toggle switch and a pressure cut-off switch.
Put them both in the glove box out of site.
When it reached 110psi the switch turned off the clutch.
Worked wonderfully and as far as I know it still works great.
I sold the truck but I still see it around sometimes. Miss my dump truck.

Pooh Bear

 

[rjgogo]

I added an air compressor to my pickup years ago.
I had a 1970 Ford F350 dump truck.
I had an air tank mounted to the frame behind the cab. But it just had an
air valve on it for like airing up tires. Used a tire chuck to fill it up.
Blew up the motor in the truck one year and had to get another one.
Got one from a 79 Lincoln Mark V and it had an A/C compressor on it.
I plumbed the A/C compressor into the tank and up into the cab.
Put a pressure guage in the cab where I could see it.
Wired the electric clutch thru a toggle switch and a pressure cut-off switch.
Put them both in the glove box out of site.
When it reached 110psi the switch turned off the clutch.
Worked wonderfully and as far as I know it still works great.
I sold the truck but I still see it around sometimes. Miss my dump truck.

Pooh Bear

for something a little more automated for a Jeep or Pick up truck do google search for "on board air"

I have it in my jeep and it is great. presure gauge to shut of when it hits 110.

Uses a York compressor which is an oil bath type instead of the rotary units. you can get them from the junk yard for $25. I suppose you could gang a few together and run them off belts from the PTO and use the clutch to disengage the compressor when it reaches the desired PSI there is a two belt pully on them that would make it pretty easy to gang them up.