One pump, 3 cylinders how to split it up?

[allarizonaparts]

First off I'm new to the forum and I've searched but can't find the answers to my problem. We had a trucking company and our best mechanic taught me that if you don't know the answer just ask, theres people out there that knowthe answer so here is the questions. I have a log splitter with a push ram that has a 5" bore and a 24" stroke with a 2" rod. I built an extada-crane that the lift cylinder is 3" and an 8" stroke. The extenda-cylinder is 2" with an 18" stroke. The pump is a Haldex/Barnes 16 gpm pump powered by a 10 hp diesel engine. I put in a Prince adjustable priority flow divider. The 5" ram moves at around 8 gpm on the excess port. The priority port goes to the crane and and I have it adjusted to about 3 gpm so it doesnt move to fast and hurt somebody or tear itself up. Where is the rest of the fluid going because the 5" ram is moving so slow? It has a 12 gallon tank with an open breather. I'm thinking of putting on a 2 spool valve for the crane with a closed circuit. The inlet outlet ports of the valves are 3/4" for all of them. If I put the closed circuit on the crane end would the main ram have all the flow or am I missing something?

 

[J_J]

If the pump you are using is a Barns 2 stage pump, the fluid is flowing all the time, and what is not used goes to tank. Just use a log splitter valve and another 2 lever valve for the crane and whatever, maybe log lift. You will have full flow from the two stage pump. If the crane or log lift moves to fast, install a needle valve to control the flow.

 

[kennyd]

Welcome to TBN

You can NOT put a CC valve in your system, so forget that idea...If you use these calculators (left side of the page, "force and speed") you will see that at 8 GPM, that cylinder is only gonna extend at 1.6 inches per second.

I think the better way to plumb your setup is to loose the priority valve so you have full flow through all of the valves, then you can use inline flow restrictors on the work ports of the crane valve to control speed. The use of 1/4" hoses would help also for the crane cylinders.

 

[RickB]

Welcome to TBN

You can NOT put a CC valve in your system, so forget that idea...If you use these calculators (left side of the page, "force and speed") you will see that at 8 GPM, that cylinder is only gonna extend at 1.6 inches per second.

I think the better way to plumb your setup is to loose the priority valve so you have full flow through all of the valves, then you can use inline flow restrictors on the work ports of the crane valve to control speed. The use of 1/4" hoses would help also for the crane cylinders.

Fully agree. I see no need for a flow divider, and it probably is hindering.

 

[teg]

...then you can use inline flow restrictors on the work ports...

These work great can you can slow it down to a crawl, if you need to.

 

[oldnslo]

to the OP.

Your priority flow divider is a good choice IF you want to operate more than one function at a time. It will keep the ram speed constant regardless of what you do with the by-pass or excess flow. NOTE: When your operating pressure exceeds the the two stage kick down point you potentially not have any flow for the by-pass circuits.

What you may want to consider is installing the priority valve in the power beyond port of the main ram valve. This would allow you to reduce the flow to your auxiliary functions and give a more constant speed with out excessive pressure loss like needle valves create.

A couple of draw backs with the priority flow divider are:

These work via pressure drop so you are creating heat. Estimate 150 - 200 PSI loss average.

If the priority flow is blocked all flow will stop to all functions.

Roy

 

[AKKAMAAN]

Flow dividers are useful, when you have to operate simultaneously synchronized actuators.

Priority valves are useful when you secure flow to a part of the system (sub system) that needs to be able to operate at the same speed, independent of pump rpm (flow). Power steering on a tractor is such a sub system.

Skip the flow divider on your log splitter. It will only do more harm than good for you. Like limiting your splitting cycle time, and creating unnecessary heat losses....

 

[allarizonaparts]

Thanks for the input I've read your posts and it got me to thinking....
I think I have the solution. I looked at how it was plumbed without the extenda-crane. ( just like an ex-tenda backhoe ) I ruined a fender because it didn't have enough reach. I have a 3/4 input output 3000 psi detent valve for the 5" push ram without a power beyond conversion. The pump is a 2 stage 16 gpm haldex. I agree with getting rid of the priority valve!! The other valve for the crane is a 2 spool with power beyond. I don't want to buy another "main" valve with pb so what I'm thinking is instead of the priority valve is placing a tee in the place of the priority valve and a closed circuit to the crane giving the push cylinder all the flow. To slow down the crane from the 16 gpm flow inline needle valves to the work ports. Does all of this seem reasonable? I'm going to post pics as I finish it. Clint

 

[kennyd]

Thanks for the input I've read your posts and it got me to thinking....
I think I have the solution. I looked at how it was plumbed without the extenda-crane. ( just like an ex-tenda backhoe ) I ruined a fender because it didn't have enough reach. I have a 3/4 input output 3000 psi detent valve for the 5" push ram without a power beyond conversion. The pump is a 2 stage 16 gpm haldex. I agree with getting rid of the priority valve!! The other valve for the crane is a 2 spool with power beyond. I don't want to buy another "main" valve with pb so what I'm thinking is instead of the priority valve is placing a tee in the place of the priority valve and a closed circuit to the crane giving the push cylinder all the flow. To slow down the crane from the 16 gpm flow inline needle valves to the work ports. Does all of this seem reasonable? I'm going to post pics as I finish it. Clint

Clint, you can not use a CC valve-end of story my friend, and no Tee's on the high pressure lines. The last valve in the chain does not need to be PB equipped, so plumb that one last with the OUT port going back to the tank.

 

[J_J]

My understanding of allarizonaparts situation is this. He is not talking about a CC valve. He is talking about a closed circuit. If you have two valves in series, The lever that you operate will have full hyd flow, and can be feathered. The valve first inline will have priority. I would install a two spool valve with PB first inline, and then a Prince log splitter valve next. This setup will do what you want. If any cyl is to fast, either feather the valve or install a needle valve to control the flow. If you are thinking heat build up, the crane probably will not be needed for a lot splitting. It will depend on the weight the crane is lifting as to whether the valve will be using high GPM's or low GPM's. In the normal splitting mode, you will be using the log splitter valve, with full force.