making a chipper for a PT?

[BobRip]

Just some data that someone might can use.

Hydraulic Pumps & Motors

Pumping = 1 Hp = 1 GPM x 1500 Psi
(linear relationship i.e. 2 GPM @ 1500 Psi = 2 Hp)


Hp to drive hydraulic pump = Psi x GPM / 1714


Efficiency - typically assume hydraulic pump/motor efficiency of 85%


Hydraulic motor torque (in-lb) = Pressure (Psi) x motor displacement (in3/rev) / (2 x Pi)


Hydraulic motor speed (RPM) = 231 x GPM / motor displacement (in3/rev)


Hydraulic motor power (Hp) = Torque (in-lb) x RPM / 63025

The PT 422 and 425 are rated at 8 GPM at 2500 PSI = 20,000 somethings. Divide that by 1500 and you get 13.3 horsepower. 13.3 * .85 = 11.33. Sorry for my previous memory of 15 horsepower. That's what I get for counting on my memory. Thanks for the lession J_J.

 

[J_J]

Bob, this is not stuff that I keep in memory either. I give credit to the age of computers, and the Internet.

 

[J_J]

You are right, I have a Bearcat PTO chipper that I use on my Kubota 22 hp diesel. It chips and shreds fairly well, but it takes just about all the available HP to run it, A 4 in log will slow it down somewhat. Again, you need lots of gpm and pressure, and the right motor.

It ain't no PT, but it is one **** of a mulcher/chipper.

http://craneworks.com/displayphoto.asp?photoID=46771

 

[woodlandfarms]

The PT 422 and 425 are rated at 8 GPM at 2500 PSI = 20,000 somethings. Divide that by 1500 and you get 13.3 horsepower. 13.3 * .85 = 11.33. Sorry for my previous memory of 15 horsepower. That's what I get for counting on my memory. Thanks for the lession J_J.

OK. now I am going to show how bad I failed physics. The 1850 is rated 8GPM at 2500PSI.. So, wouldn't it be 11.33HP? I am missing something huge here...

 

[J_J]

I believe the 1850 is rated at 18 gpm, at 3200psi

 

[MossRoad]

I would think that if you could find an old chipper that ran on a 10HP or less motor you could adapt it to a hydraulic motor very easily. Those gas engine chippers usually turn the engine at 3600 RPM and have belts that drive the chipper. You would have to gear up a hydraulic motor with pulleys of the proper size to get the chipper to turn at the original speed.

I seriously thought about this a while back. I even went to a lawn and garden dealer that has some used chippers. I could have picked one up with no engine for about $300 and then put another 3-4 hundred in a hydraulic motor and pulleys, etc... it looked to be a very doable project. However, I realized I have little use for a chipper right now. Maybe in a few years.