How big of a pump can I run off a Kubota L3800.

[oldnslo]

4570,
Another possible option to get both speed and force is a regenerative system. This would require extra valving to provide the region function but could provide the speed and force. Problem is that region typically works best when the cylinder has a ratio close to 2:1. On a 5" bore this would be a 3.5" rod.

 

[4570Man]

How does that work?

 

[oldnslo]

Regenerative function is where the oil exiting the rod end is fed back into the cap end when the cylinder is extending. This provides faster extend speed at the loss of force. A pressure activated valve can be installed that allows the shifting from regen to normal function once a preset pressure is reached.

Regen circuits typically require large hoses and ports from the rod end to the cap end and are very sensitive to any load or back pressure during the extend stroke.

 

[motownbrowne]

Like I mentioned in my first post, I'm running a 21 GPM pump. Mine is a knockoff of the Prince pump. My splitter has a 36x5" cylinder with a 2" rod. I wish the rod was bigger for a faster cycle time, but otherwise I'm 100% happy with my setup. One thing I like is that with the large pump I can run my tractor at about 2200 RPM (540 PTO is at 2600), and still have a very reasonable cycle time. I like the noise level much better at that engine speed than at 2600.

I also considered going with a smaller pump to get more splitting force, but I'm glad I didn't. So far i have only found a couple of pieces I couldn't split at 1700 PSI. I'm splitting mostly white oak and elm. Oh, and this is my wedge:

Also, if you go with a 20 GPM pump, don't forget that you're gonna need a big tank. I've got 20 gallons of fluid in my splitter, but I think I'm gonna add another 5. I'm pretty sure I have room for it. I don't usually run the splitter for more than a couple hours, but the fluid gets up to about 130-140ｰ in that time. Another option would be a cooler, I suppose.

 

[4570Man]

I've got a 30-40 gallon tank. I might have to put an oil cooler on it but I'm going to try it without one first.

 

[Sawyer Rob]

Also, if you go with a 20 GPM pump, don't forget that you're gonna need a big tank. I've got 20 gallons of fluid in my splitter, but I think I'm gonna add another 5. I'm pretty sure I have room for it. I don't usually run the splitter for more than a couple hours, but the fluid gets up to about 130-140ｰ in that time. Another option would be a cooler, I suppose.

Your system must be more restrictive than on my TW, making more heat... I'm running with about 14 gallons and I don't think it's ever got that hot. No cooler either...

SR

 

[LD1]

Think of Regen like this.......

If you got a 5" cylinder with 2.5" rod.....

It will extend with the speed ( and force) as if you only has a 2.5" diameter cylinder. Once the force needed to split the wood becomes more than the 2.5" x 2500psi can handle....it would revert to normal operation and give full force of 5" bore x 2500 psi. So similar in function to a 2 stage pump, but with a single stage. So you will get fast cycle until force demands more.

Retract stroke is uneffected. It's gonna be whatever the gpm dictates. Can't have Regen on retract.

Most loaders have Regen on dump. But not for speed. Rather to keep the cylinder full of oil

 

[motownbrowne]

Your system must be more restrictive than on my TW, making more heat... I'm running with about 14 gallons and I don't think it's ever got that hot. No cooler either...

SR

Yeah, there's a couple hard 90s in there. The auto cycle valve might make things pretty messy without them, but I have thought about seeing if I can do without them. My understanding is that as long as I'm under 180, it's fine, but I don't want to push it.

 

[4570Man]

I couldn't find a PTO pump that doesn't break the bank that went much over 2000 psi. I decided this wedge needs all the help it can get and that just wasn't going to work. I ordered a 28 GPM 2 stage pump that is rated at 3000 psi on the low side continuous duty and 4000 psi briefly. I've got a gas motor that's around 20 hp so we'll see how it works out. If this thing really makes 4000 psi that's around 39 tons. As far as heat goes I'm going to try it without an oil cooler but I'm not sure it'll work. I don't have anything substantial enough to handle the entire return flow so I'll probably just pump oil through a free radiator or transmission cooler with a 12 volt pump. My other splitter that got stolen had around 7 gallons with an 11 GPM pump and it got pretty hot.

 

[jenkinsph]

4570Man,
Before you apply up to 4000 psi to this used cylinder you should know what pressure the cylinder is rated for.

Just a guess but I would think a two section pump with 1500 psi low stage and 3000 psi high stage would work well with the 20 hp motor.