opposing cylinder plumbing

[cbailey1956]

Hello, planning next years log splitter build. I plan to build a splitting table that uses wedges on both ends and a movable block in the middle. I would like to use two cylinder underneath to move the block back and forth. I have a matching cylinder set in the 3 inch bore range. I want to set them up where they each have the base at the opposite end. When the center block moves in one direction, one cylinder is extending while the other is retracting. This should keep the pressures equal on each stroke. Is this a problem with the different volumes on the same line from the valve and a T connection to split the flow? Valve output to one extend port and "T'd" off to the other retract port. Was thinking 3 inch cylinder push and pull rating would be very close to 4inch cylinder push rating.
Thanks, Craig

 

[J_J]

4 in cyl 2 in rod@ 3000 psi = 37,699 lbs

3 in cyl 1.5 rod@ 3000 psi = 21,206 lbs

You might consider one of these.

Powerhorse Horizontal Dual Split Log Splitter — 20-Ton, 208cc Powerhorse Engine | Log Splitters| Northern Tool + Equipment

 

[cbailey1956]

Thats an ok machine but look at the multitek tempest for more of an idea of what I plan. I haven't bought anything new (except tools and 1 car), even built my 3600 sq ft house. I could just use one 4 or 5 inch cyl and lose some power on the retract but already have the two 3 in and length is not an issue. I was thinking that one cylinder would be pushing (21,206 lbs), and the other could be pulling (15,904lbs). that adds up to 37,110 which is close enough to a 4 inch force. Speed would also be consistent for both side to side movements. Thats assuming my design is possible. Thanks, Craig

 

[whis]

Tempest doesn't work good with knotty wood.

 

[cbailey1956]

I was thinking the same thing. My situation is that I require different sizes of split wood for different customers. I am building a new standard splitter with 5" ,32" stroke and a 16" tall wedge to handle larger rounds. I currently have a 4" 24" stroke that handles 90% of what I can get. Able to get larger knarly rounds from several sources. Normally split into halves and then quarters. Select good pieces to make pretty wood for customers that want smaller splits. That is why I want the seperate dual action to speed up the processing. Also want to have a add on wedge section to make kindling. More plans than time and money.

 

[oldnslo]

Hello, planning next years log splitter build. I plan to build a splitting table that uses wedges on both ends and a movable block in the middle. I would like to use two cylinder underneath to move the block back and forth. I have a matching cylinder set in the 3 inch bore range. I want to set them up where they each have the base at the opposite end. When the center block moves in one direction, one cylinder is extending while the other is retracting. This should keep the pressures equal on each stroke. Is this a problem with the different volumes on the same line from the valve and a T connection to split the flow? Valve output to one extend port and "T'd" off to the other retract port. Was thinking 3 inch cylinder push and pull rating would be very close to 4inch cylinder push rating.
Thanks, Craig

I presume they will be mechanically tied to the same push block. If yes then this concept will work. It should also give you even flows in the return line making valve sizing a little easier.

Remember any back pressure in your system deducts from your available splitting force.

 

[cbailey1956]

Yes both cylinder rod ends to the block, all ports reworked with true 3/4" welded in fitting adapters to reduce flow restrictions I usually consider myself competent in hydraulics but occassionally think I am a complete idiot. Its always a good idea to run ideas past others. My next question was options for valve. The normal splitter valve detents in retract and pressures off. I would like to have that option in both directions. I was looking at the auto cycle valve in Surplus Center but unsure if it could be set up for pressure return and detent off to match the extend cycle. One pressured extend and retract cycle per lever operation.

 

[oldnslo]

Not familiar with the Auto cycle but I thought the way they worked was to fully extend the cylinder then kick out to fully retract the cylinder and wait for operator input to start next cycle. Wouldn't this do what you want provided the splitting pressure required doesn't cause the valve to short cycle?

 

[cbailey1956]

My understand of the valve is that extend detent is adjusted to 300 psi less than the retract with a max detent setting of 2000psi. That should give only 1700psi extend pressure and 2000psi retract pressure with a system pressure relief from 2000-3000psi. Those really drop the amount available for splitting the tough rounds.