building splitter - pump pressure / relief valve questions

[Northeaster1]

Hi folks,

Father-in-law is almost done building a nice, new splitter, but we have a couple of questions.

Have a Haldex-Barnes 11gpm 2 stage pump, with a max working pressure of 3000psi.
The 3.5" x 24' cylinder has a max pressure of 2500psi.

Questions:

1. Does the pump have an internal pressure relief valve, that will protect it, if something were to block downstream, so to speak - so it will not blow the side out of the pump?

2. Using an old spool valve, from an old log loader, that has an internal, adjustable pressure release valve to control the flow to the cylinder. Should we adjust this to 2500psi, as the pump is rated higher than the cylinder?

Thanks in advance for any help!!

 

[triptester]

The pump does not have a relief valve. The relief in the control valve will be suffient. A 2500 psi setting will be fine.

 

[Northeaster1]

Thanks for the quick reply!

Had been wondering if we needed the relief valve in the control valve, or if we could get by by taking it out, and not having to adjust it.

To adjust it, I guess we will have to temporarily rig up a gauge, in line with it, and adjust the spring tension till we see around 2500psi - does that sound right?

Would there be much chance of damaging anything, given the cylinder's 2500psi rating being fairly close to the pump's max output of 300psi, if we didn't use it?

 

[WhitePine]

There must be a relief in the system or you risk breaking something and/or possible injury. Don't leave it out.

 

[triptester]

A gauge in the line between the pump and control valve would be the best for adjusting the relief valve setting. The pump is rated for 3000 psi but it will produce greater pressures until either the pump gets damaged or the engine stalls.

Hydraulic components have a built-in safety margin that is greater than the rated maximum pressures that allow for surges.

 

[Northeaster1]

Thanks again for the info. That answers my related question of whether or not it would try to keep pumping beyond 3000psi (if enough rpm/hp was available).

We will only be using a 4hp Honda (had it anyway) - modeled it after a borrowed splitter that uses a 5hp Honda, with same pump and cylinder size. On the borrowed one, it splits anything with the engine running only about 1/2 throttle, so we figured if the 4hp revs a bit higher, it should still produce enough power.