Is it OK for the system to go to relief all the time?

[Farmerford]

Greg:

Be sure the relief valve "cartridge" in the RD-400R flow divider is the one with the 500-1500 psi range. Prince components usually have a choice of two relief cartridges, one with a range of 500-1500 psi that comes preset at 1000 psi, and one with a 1500-3000 psi range that comes set at 2000 psi. Surplus Center probably ordered those flow dividers with the 1500-3000 psi cartridge; if so, you will need to buy the lower pressure cartridge. I don't know if Surplus Center carries the separate cartridges.

That is one of the reasons I recommended the variable flow divider without a relief: it is actually cheaper than the adjustable one, can be easily adjusted with the hand lever down to zero priority flow if you choose, and the price difference is a large part of the cost of a Prince stand-alone relief valve that comes preset at the 1000 psi you need.

Chuck Ford

 

[J_J]

Relief setting is easy enough to check, Just plumb a hyd gage in the cyl circuit, and extend the cyl.

 

[gsdavis1]

OK, so when installing the priority valve with relief built in, is it OK to plumb the relief port right to the Excess Flow line? That will go to the tank eventually...after 2 other open center valves.



Greg

 

[gsdavis1]

I have given careful consideration to a separate relief valve and then an adjustable flow divider. But I am trying to keep the plumbing simple. I don't have much space to work with.

That being said, I think Parker makes a priority flow divider that is adjustable and has internal relief. But it is more money than the prince one.

Parker Valve Here

The priority valve is an item that has to be purchased separate, but you can see it in the picture.

Greg

 

[J_J]

OK, so when installing the priority valve with relief built in, is it OK to plumb the relief port right to the Excess Flow line? That will go to the tank eventually...after 2 other open center valves.



Greg

If the EF goes directly to tank, it should be OK. The relief can not go through another valve because of high pressure. If the last valve in a circuit is activated, there will be high pressure through the total system.

Relief should always go to tank/reservoir.

 

[gsdavis1]

What about this model...

Flow Divider

Will this work?

 

[gsdavis1]

Oops, I just noticed it said that the Excess Port must go to tank.

 

[J_J]

Oops, I just noticed it said that the Excess Port must go to tank.

What is really says is that the EF can go to tank, or provide flow to another circuit.

https://www.surpluscenter.com/adspecs/AS9-4169-10.pdf

RD150-16

 

[David Devuono]

Man, I think these guys just can't wait until I start asking questions, I have a whole bunch of parts ready to assemble and I think there is a total of 7 pressure relief vavles. Guess if I don't get it right its gonna sound like a pig farm with all the squeeling. Good info, good luck gs.

 

[gsdavis1]

Now I need to figure out how large of a Priority Flow Divider I need. In other words, how much flow to direct to the steering.

I have bought a orbital valve from a Lift Truck Surplus Store. It is an Eaton and here are the specs

DESCRIPTION: STEERING CONTROL UNIT
OPEN CENTER NON-REACTION
RATED FLOW CAPACITY 3.0 GPM/11,4 LPM
DISPLACEMENT CODE 08 (4.50 CU.IN/REV / 73,8 CC/REV)
FOUR .5625-18 PORTS
.375 MOUNTING THD.
RATED SYSTEM PRESSURE 1500 PSI/103 BAR
RATED RETURN PRESSURE 100 PSI/6,9 BAR


My pump is rated at around 4.5 GPM. The steering cylinder that I am using is 1.75 bore with a 6.5 inch stroke. I have no idea how "displacement" plays into all this. The valve displacement is listed above.

Will 1.5 gpm be too little for the steering? I don't want the steering to be terribly slow.

Greg