Hydraulic divider question

[etpm]

I have a non-adjustable divider that I bought from a fellow on TBN. Since I bought it, about a year ago, the person has not answered and of my emails. So I'm asking here for advice. I don't know if my divider has a pressure relief built in and I don't know how to find out. I am willing to take it apart and look inside if need be. This divider is for adding power steering to my YM2310 tractor. I am thinking I could test the divider by connecting it to the pump and the power steering cylinder valve and leaving the bypass port hose open to a clean bucket. Then I can watch the fluid as it comes out when I actuate the power steering valve. The fluid coming out of the bypass port should never stop if there is pressure relief built in, right?
I did take the divider apart once in order to drill and tap a couple mounting holes. It was a good thing I did because I found aluminum chips from previous machining operations inside. The divider has 3 ports. Inlet, regulated, and bypass. It also has some sort of spring loaded valve inside. When I took the thing apart I found the aluminum chips inside this valve.
Besides the test I describe above is there anything else I can test? And would the test I describe above work? Would it be likely to damage anything if the divider doesn't have a relief?
Thanks,
Eric

 

[oldnslo]

Post some pictures of the valve. This would help in attempting to determine if your valve has relief in it.

 

[mrmikey]

Just guessing obviously but I'd say doubtful of having a pressure relief.

I am thinking I could test the divider by connecting it to the pump and the power steering cylinder valve and leaving the bypass port hose open to a clean bucket. Then I can watch the fluid as it comes out when I actuate the power steering valve. The fluid coming out of the bypass port should never stop if there is pressure relief built in, right?

The power steering valve should have 4 ports. A, B P and T so moving the steering wheel should not affect the flow from the divider provided your pump has sufficient flow. You say it's regulated, to what flow rate?
As was said above, pics would help

 

[rScotty]

Photos would help.,,,,maybe. SurplusCenter.com has some excellent drawings in their hydraulic device sales online. You might even find yours there.

There are different types of divider valves. Your test will work differently for a priority divider versus a percentage flow divider. We don't know which yours is.

There are also two main types of relief valve attached to the divider. The more common type - which is what I think you want - has a standard whole system pressure relief valve that dumps over-pressure into a relief valve return line that goes straight back to the sump. It only activates if the whole system pressure is too high - which can happen with a priority flow divider when the hydraulic cylinder comes to the end of it's throw, or a front wheel doesn't want to turn any farther. That type of relief is your basic safety relief. Physically, it often looks like a thumb on the side of the divider. It has a hose connection and also has an adjustment screw that is often set at 1200 to 1500 psi on a 2500 to 3000 psi system. I'll attach some pictures below.

The other type of relief protects one of the divided circuits by not allowing one of the internal divided flows to have a much larger pressure than the other. It is a differential pressure relief and protects one side only. That's type is more likely to be completely internal and not require an external hose. It protects one of the divided flows, but not the whole system pressure.

rScotty

Here are some great pics of a priority type divider with a whole system relief valve. Credit to SurplusCenter.com

 

[etpm]

Thanks All for the replies. Tomorrow morning I will take pictures of the divider. I will also take it apart to show what I think may be a relief valve and take pictures of it too. So please look tomorrow for pictures. Also, regarding the power steering valve, it only has two ports. In and out. I think it must be an open center valve.
Thanks a bunch Folks,
Eric

 

[mrmikey]

Also, regarding the power steering valve, it only has two ports.

Well that's a different beast then, at least to me .
Listen to Scotty, he knows

 

[etpm]

OK folks, pictures. And a little more info. Inside the cartridge I removed is what appears to be a piston. I didn't take the cartridge itself apart so I don't know for sure. On two of flats on the hex part of the cartridge are stamped some numbers. One flat has A1113 stamped on it. On the flat opposite is stamped PFR1-F-1.50.
Thanks,
Eric

 

[oldnslo]

That does not have a relief valve. It is a priority flow control only. The piston is spring loaded and that is how the valve is pressure compensated so provides a constant flow out the regulated flow port

 

[rScotty]

That does not have a relief valve. It is a priority flow control only. The piston is spring loaded and that is how the valve is pressure compensated so provides a constant flow out the regulated flow port

That's the way I see it too. Thank you, oldnslo. That photo is a single piston actuated valve and so is most probably a priority flow divider .... although it could just as well be called a flow regulator - it just depends on which outlet port you are referring to. It doesn't look adjustable - or at least I don't see any way to adjust the spring force. No relief valve that I can see. Back to the drawing board.

Just so you know, a common type of proportional - not priority - flow divider would have two similar spring-loaded pistions moving in oppostion to each other.

BTW, my apologies because I directed folks to surplus.com. yesterday......Totally my mistake. That is us wrong URL. The right one is SURPLUSCENTER.COM. and then select the hydraulic option on the left column. I'll go back and edit my post.
rScotty

 

[rScotty]

Also, regarding the power steering valve, it only has two ports. In and out. I think it must be an open center valve.
Thanks a bunch Folks,
Eric

That's a whole different device. I encourage you to draw out a hydraulic flow diagram. It doesn't have to be a formal schematic, just something so a couple of us old hydrualic guys can help.

Yes, your YM2310 has an open center hydraulic circuit. Most compact tractors have that type.