Hydraulic Question

[Sawmill]

I saw a wood splitter on a firewood processor last week and I notice the hydraulic lines on the cylinder for the splitter were 3/4 inch lines but the ports on the cylinder and control valve were only 1/2 inch. Is there any advantage to using the bigger line on a smaller port? He told me that the splitter was real fast but when I seen it work I did not think it was all that fast. I am building one and would like to know before I add the hydraulic lines to it. Thanks

 

[pdqdl]

Yes,...and no.

If there is a very long hydraulic hose, there will be some pressure drop along it's length. That probably won't be noticable, so long as the volume of the pump does not exceed the capacity of a 1/2" hose for the operating pressure of the system.

If it's that big of a pump & motor, then there will be significant pressure drop across the 1/2" valves, and the pressure relief valve will probably be in full time bypass. That would lead to overheating.

That scenario is very unlikely. It was probably just put together by someone who wanted to get the least pressure drop to the cylinder. Without paying for a bigger valve ($$).

If it is the suction line from the the pump to the tank, the pressure drop could be more significant.

 

[AKKAMAAN]

Regenerative valve

If you build your own splitter. Use this nice tech. A regenerative valve that speed up your splitter when there is some light duty.....
This valve goes between the directional valve and the cylinder.....its automatic and speeds down at a adjustable pressure.....
http://www.akkamaan.com/firewood/regenventsystem.JPG

this directional valve have 4 postions, 2 for splitting 1st is full force and 2nd is extra speed with lower force.
http://www.akkamaan.com/firewood/system.JPG

Example. A cylinder with 4" diam, and a piston rod with 2" diam, will give you 4 times faster splitting on light duty. that's 4 to one area relation on outgoing verus ingoing piston. You customize this relation by choosing bigger or smaller psiton rod when you buy the cylinder.

Dont forget to add an pressure gauge direct after the pump and make your engine throttle automatic when activating the directional valve. That save some fuel and prevent overheating in the hydraulic system. It also reduces the noise emissions..........

 

[mga]

I saw a wood splitter on a firewood processor last week and I notice the hydraulic lines on the cylinder for the splitter were 3/4 inch lines but the ports on the cylinder and control valve were only 1/2 inch. Is there any advantage to using the bigger line on a smaller port? He told me that the splitter was real fast but when I seen it work I did not think it was all that fast. I am building one and would like to know before I add the hydraulic lines to it. Thanks

are you building a splitter or processor?

if a splitter, so with the same size as your ports on the control valve. try to avoid using 90 degree fittings, if possible.

 

[kevin j]

Prince also has a manual control valve with 4th position regeneraton build into it. Just out early this year, but I have not seen retail source yet. I'd like to try one.
Advantage: no separate component, it is built into the manual valve
Advantage: Predictable and under operator control. you know it goes into regen/high speed only when manually in the regen position. The inline one shifts in and outof regen based on pressure, not under operator control.

Advantage of the inline separate regen valve: can add to an exisitng circuit (although it will cost about the same as replacing the entire manual valve), and automatic operation, don't need to manually move the valve handle to regen position and back.


Misc notes:
-Regen ONY works in extend, retract is simply regular speed determined by pump size.
-With the increased speed comes less force of course. The 4B 2R cylinder in example above simply acts as a 2B cylinder during regen, with increased speed and decreased force. (This still is likely enough force in many cases, especially resplitting smaller pieces.)
-Check the speed carefully to make sure it is not too fast and abrupt.


kcj

 

[Jkebxjunke]

was it a 'home built' one? if so maybe thats what he had laying around and was just using that instead of buying new hosed.... just a thought

 

[AKKAMAAN]

Prince also has a manual control valve with 4th position regeneraton build into it. Just out early this year, but I have not seen retail source yet. I'd like to try one.
Advantage: no separate component, it is built into the manual valve
Advantage: Predictable and under operator control. you know it goes into regen/high speed only when manually in the regen position. The inline one shifts in and outof regen based on pressure, not under operator control.

Advantage of the inline separate regen valve: can add to an exisitng circuit (although it will cost about the same as replacing the entire manual valve), and automatic operation, don't need to manually move the valve handle to regen position and back.


Misc notes:
-Regen ONY works in extend, retract is simply regular speed determined by pump size.
-With the increased speed comes less force of course. The 4B 2R cylinder in example above simply acts as a 2B cylinder during regen, with increased speed and decreased force. (This still is likely enough force in many cases, especially resplitting smaller pieces.)
-Check the speed carefully to make sure it is not too fast and abrupt.


kcj

For the 4 pos valve, there is a dealer in Kent WA, Spencer Fluid Power, ph# 800-367-5646, they quoted me around 100$ plus shipping, but they wanted at least a month to deliver

the in line valve can usually be shipped the same day or next day from (6 weeks from manufacturer), Hydra-Power Systems, in Portland OR, ph# (503) 777-3361, a 120 l/min valve is about 175$ in aluminum housing.

 

[Sawmill]

Thanks for all the help. Now to answer some questions. I am building a processor with the splitter on it and I have a 16 foot elevator connected to it. I have used the processor I have to cut slabwood from my sawmill for the past 8 years but now I need it to cut logs for firewood so I am remodeling it to use a splitter with the cut off saw. Until I get everything running just so I am going to use my skid steer hydraulic aux power to run it and latter on I have a 24 hp engine with a 20 GPM pump to hook up to it. The wood processor I looked at was a bought one made by Hudson. The hose thing had me wondering what the advantage there was to running larger hoses. Again thanks for all your help.