Firewood Processor Hydraulic Questions

[Wild Bill the 2nd]

Would you suggest I go that high in displacement?
I see I can get a 1.14ci or 1.35ci front and couple that with a .5ci back for everything else.

 

[Wild Bill the 2nd]

So for now my plans would be to run a 1.35ci front and a .5ci back. That would give me 17.4 and 6.5 GPM at 3000 RPM.

I would assume that with a multi-section pump I would be getting the right flow for the application with a single engine. The high flow would simply go to the saw. The lower flow would run the rest of the hydraulic cylinders.

Correct me if I’m wrong but I wouldn’t need to worry about running 23.9 GPM (17.4+6.5) with a 22 HP engine since I would never be running both pumps to max pressure at the same time. I like that.

So your pretty much saying the “double the HP requirement for gas engines” statement is pretty much bupkis?

 

[J_J]

If you ever did need the 23.9 GPM, at 3000 psi you would need 49 HP.

17 GPM at 3000 psi needs 35 HP.

6.5 at 3000 psi needs 13 HP

 

[oldnslo]

So your pretty much saying the “double the HP requirement for gas engines” statement is pretty much bupkis?

Depends on the true HP / torque capability of the gas engine. A lot of motor manufacturers over rated the HP capabilities of there gas engines.

 

[J_J]

Using a 13 GPM two stage pump in low pressure high GPM at 650 psi requires about 6 HP.

---------3.4 GPM------3000 psi---------------7 HP

They use a 6.5 Hp engine on this log splitter.

 

[glastron23]

you will very rarely be using more than 2 functions at one time, when sawing you will be using the down force cylinder and not the feed motor, when splitting you will be advancing the log for the saw but will not be sawing because you need to wait for the ram to retract,you will only be seeing max psi when you stall the saw or splitting ram, the saw down cylinder will never see max psi.
we installed a sequence valve on the log clamp/ saw down cylinder spool valve, this requires the log clamp to come down and hold the log (set at 400 psi) before the saw will lower, then when finished sawing you raise the saw and then the log clamp will release, this will help prevent you advancing the log with the saw in the way.

 

[Wild Bill the 2nd]

We are actually planning on being able to cut and split at the same time. We have two seperate engines and pumps for splitter and saw. The splitter will have a plate on top of it that the cut log can rest on until the cylinder fully retracts. At which point the log will in theory drop into place in the splitter.

I like the idea of not mangling the saw or the clamp by advancing the log too early.
This will be something I need to look into. Is it a cartridge model that is required in order to release the clamp?

Do you happen to know the Mfr / Model?

 

[glastron23]

we used the Sun hydraulics SCCA units http://www.sunhydraulics.com/sites/default/files/media_library/tech_resources/TT_US_Sequence-New.pdf

 

[Wild Bill the 2nd]

I've looked at some of their stuff, it looks nice. Did you contact the company directly, find a local distributer, or are there online distributes that carry their products?

 

[Scooby074]

Depends on the true HP / torque capability of the gas engine. A lot of motor manufacturers over rated the HP capabilities of there gas engines.

^This.

HP ratings are usually correct for electric motors. Gas motors, particularly small engines can be all over the board for torque and HP regardless of what the labels say on the box. So much so that I believe there has been a lawsuit over it.

The 2x Hp for gas engines rule of thumb comes from that. I know that even though I technically should have enough HP in my Subaru small engine to run my pump over 2200Psi, in practice the engine comes up short. Its always to better to have too much power as opposed to be trying to find more.