Hydraulic help

[Ditchdoc 129]

I'm new to this forum thing so please be easy on me. What I am doing is trying to build me a trailer with a knuckle boom on it and I need some help with sizing a hyd. pump to run the motors and cylinders. What I will be using is 1 Char-lynn 101-1016 motor 22.6 cu in, 1 dh400 151-2129 motor 24.2 cu in, 2- 3 in bore 14 in stroke cylinder and 2- 4in bore 28in stroke cylinder and 2- 2 in bore 8 in stroke. I need some help with how big of a hyd pump will be needed to run these things. thanks

 

[J_J]

Volume of a hyd pump in GPM determines the speed of any motor, and speed of the cyl. , and the pressure rating of the pump determines the max pressure. The motor can be varied with a balbe, and cyl can be restricted if needed.

10 GPM, flowing through a 20 cu in motor, will turn it at 116 rpm. and 20 GPM will turn it at 231.

40 GPM's through 20 cu in, will turn the motor at 462 rpm.

Will both motors be running at the same time.

So if you need to pump 40 GPM's to the hyd motors, and work the cyl intermittently, then you will need something like this. 40 GPM's at 3600 rpm, you will need a pump displacement of 2.6 cu in.

If you change the engine rpm and still need the 40 GPM's, then you will need a different pump displacement.

The HP required to pump 40 GPM's will be 82, if the pressure is at 3000psi.

Engine rpm will determine the flow rate in GPM's.

If you will turn the pump with something less that 3600 rpm, and still require 40 GPM.s the cu in will change.

What is your power source for the pump?

You will also need a valve with two motor s pools and three more spools for the 3 cyl.

Please be a little bit more specific, and someone will help more.

 

[Ditchdoc 129]

thanks for the info. The two 28 in stroke cylinders will run intermit with each other and the maybe a motor with one 28 in stroke cylinder intermit but no two things should run constant together for more that a about a min. I also look at a a 2 joystick style spool kind of like a backhoe use, but it will only flow 6 GPM will this cause a problem. as for the motor type it will be a small engine around 16 HP or whatever size needed to run pump effictive. Also due I need a two stage pump or what would you suggest. thanks for all help and comments.

 

[J_J]

A hyd motor needs steady pressure and and volume. I would not use a two stage pump for the motors.

The cyl could be run using a two stage pump, but the hyd motors need a constant gear pump. A constant hyd pump pumping 10 GPM's at 3000 psi, will require about 21 HP.

Based on your 16 HP estimated engine rpm, you can run everything here with 8 GPM's, and the 24.2 cu in hyd motors will run at 76 rpm. If you need the motors to run faster, then you need more GPM's, and that requires more HP.

The hyd motors should have a motor spool valve rated for the GPM's of the pump.

The cyl could use a joystick valve, again rated at the GPM's of the pump.

 

[KWentling]

I'm wondering what the second motor will be used for. Never been around a knuckle boom. One would swing the boom, which would need to hold position, so a motor spool valve wouldn't work. Maybe a standard valve with cushion valve would work better there. Acceptable cycle times will be an important consideration in the selection of the pump and engine HP required.

Kim

 

[J_J]

A stack valve is what is needed here. You select the valve spools for the function you need.

Build your own valve,

Surplus Center - 3 SPOOL SV VALVE OPEN CENTER