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.

 

[joelaudi]

Using york type compressor from car ac units will pump air. The only issue is that these compressors are made to pump oil along with the air to lube the intire system. The compressor will pump the oil out of the sump in no time and put the oil it whatever is being serviced by compressed air. As for using an air cylinder to tension a belt I bet it would burn up very quickly, it takes a good deal on belt tension to drive a good sized unit.

 

[Pooh_Bear]

Are the york air compressors the long cylinder shaped compressors,
or are they the ones that look like actual compressor heads.
The compressor I used was one of the long ones.
I had to add oil to my truck about once per week
and I just poured an ounce or so in the intake line for the compressor.

Pooh Bear

 

[rjgogo]

Actually the Yorks pump very little oil out as they have a sump for the oil, What little that goes out is caught by a filter. I have had the system for over 4 years and I use it several times a month and the filter only has about 1" of oil in the cup. I may have added oil to the unit once in that time.

You are thinking of the rotary type compressors that require and blow a good deal of oil. yorks are the ones that look like a compressor head.

 

[Soundguy]

Too bad you couldn't have gotten the motor out of a later model.. like a mark VII, The ones that had the air ride system... That or a chevy unit with a smog pump.... ( probably not enough psi on the smog pump. ).

A pop off valve from a gas engine job would help for a pto unit using an old air pump.. etc..

Soundguy

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

 

[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

After nearly three years (but just the last few months of building) my PTO air compressor is ready for use. Using parts from Harbor Freight, Grainger, and TSC I was able to put the thing together for less than $200.

Pictures and details to follow soon.

-srj

 

[Soundguy]

If i can ever get my hands on a unit that has a blown gas engine and that type of unloading valve.. I think one would be easy to cobble up.... just no parter's yet!

soundguy

 

[DieselPower]

Why go through all the hassle of building up a air compressor setup from scratch when you could easily adapt a compressor off of a medium/heavy duty truck. Just stop by a local junk yard that has MD/HD trucks and get yourself a used Bendix compressor. They will either have a gear on the front that is press fit, spline drive or a pulley for a belt. Most of them will have the unloader valve right on the cylinder head, if not brand new their only $12. The most common Bendix compressor is going to be a 2 cylinder but you might get lucky and run across a 4 cylinder one.

You mentioned sand blasting. Your going to need a BIG compressor to do any real sand blasting. They require a rather high CFM.

 

[Taylortractornut]

For years when I was little dad had an old piston type pump that was out of an old store reefer unit. He had it bolted to a table and a tank and we aired tires up for years with it. Later When i was 17 or so I mounted an idler pulley to it and used it on the 49 Farmall Cubs V belt drive for airng up truck tires when we had out trucking company if the shop was blocked. Yarksalso work good to I know lot of wrecker drivers that had them. I had oe on my 85 1 ton Chevy When I worked for Huffman as a service truck . I haad a pipe bumperon the fron to hold the air and fittings in a box below it. One night I picked up my girl friend atthe time in it and she didnt know the trucks AC didnt work andthat the switch I left in the dash for the AC was for the compressor. goin down the road she pushed it and about 5 minutes later I the loudest noise I had ever heard till then. I was toolin along about 75 and the hard 3/4 inch air lineto theback of the truck blew up and making a shrill whistle. The presure releif had gummed up and the fact it had all sorts of RPMs pushing it didnt help lol. I still have the truck butthe compressor set up is off it now. its was very handy if i didnt want to mess with my Gascompressor on the back of the truck I added later or if the wehter was too bad to get out and mess with it. just flip the switch and build up air before I got out of the truck and filled up 2 tanks.

Onething the cylinder type AC compressors are good for is stripping them and usingthe clutch and shft to run small hydraulic pump for a service truck.

 

[rjgogo]

Why go through all the hassle of building up a air compressor setup from scratch when you could easily adapt a compressor off of a medium/heavy duty truck. Just stop by a local junk yard that has MD/HD trucks and get yourself a used Bendix compressor. They will either have a gear on the front that is press fit, spline drive or a pulley for a belt. Most of them will have the unloader valve right on the cylinder head, if not brand new their only $12. The most common Bendix compressor is going to be a 2 cylinder but you might get lucky and run across a 4 cylinder one.

You mentioned sand blasting. Your going to need a BIG compressor to do any real sand blasting. They require a rather high CFM.

Yorks are on the trucks as well. that is the beauty of them. You can find them off of semis and off of Mercedes, Volvos and Chryslers. Took me five in the junk yard and there it was! Another 10 to take it out and I was good to go. I got mine out of a 70's Mercedes and now it is running in a 2000 Jeep. And it fills my tires and runs tools to no end.

 

[czechsonofagun]

Yup, got the same thing in my jeep. Helped me out quite few times.
For the PTO compressor I would go with electrical clutch, the most elegant solution and - as mentioned here - it can be wired to kick off when the air tank is full.