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.

 

[etpm]

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

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

So if this valve is plumbed before anything else and I turn the steering wheel until it stops in either direction the hydraulic pump will be dead headed? And then there is the risk of damage to the pump?
Thanks,
Eric

 

[oldnslo]

So if this valve is plumbed before anything else and I turn the steering wheel until it stops in either direction the hydraulic pump will be dead headed? And then there is the risk of damage to the pump?
Thanks,
Eric

You are correct in potential to dead head the pump and potentially damage something.

 

[Rich B1]

Did you look at your tractor’s hydraulic schematic or service manual? That should show you the location of the standard relief valve. If it is at the pump, then you are good to go. If not, then you need a relief between the pump and priority flow divider.

 

[etpm]

Did you look at your tractor’s hydraulic schematic or service manual? That should show you the location of the standard relief valve. If it is at the pump, then you are good to go. If not, then you need a relief between the pump and priority flow divider.

I have not been able to find a service manual for my tractor. I was able to buy a service manual from Hoye but when it arrived it was for a different model. Hoye told me that no service manual is available for my tractor but that the one they sent is close. In any case when the relief valve is functioning, such as when trying to pick up a load too heavy for the 3 point hitch, it can be heard and the sound comes from under the seat. Furthermore the manual that I have which is kinda close also shows the relief valve being located under the seat. So I don't think there is a relief valve at the pump. It looks like I will be buying a divider with a built in relief valve. I know I could probably buy a relief valve and just plumb it in but if I go that route I will need to make a mount for it and add extra plumbing. To keep things simple I'm gonna buy an adjustable divider with built in pressure relief.
Thanks,
Eric

 

[etpm]

So, now that I'm getting ready to buy a priority flow divider with relief I have a question about GPM rating. I think my tractor has an 11 GPM pump. I'm looking at one valve that's rated at 30 GPM. Would that be a problem? Could it make adjusting the flow accurately hard to do?
Thanks,
Eric

 

[etpm]

And another question. I looked at one sold by Summit that resembles others sold by many other places. But the description is slightly different. It says that for the relief to work the Ex port must be plumbed to the hydraulic fluid tank. Since my loader valve has power beyond and is open center and has a return to the tank won't it be safe to plumb the divider directly into the loader valve? The whole reason to use a divider?
Thanks,
Eric

 

[oldnslo]

A 30 GPM rated valve may be a challenge to get set to 3 or 4 GPM for steering.

On relief valve question most relief valves the spring chamber is vented to tank port so any pressure in tank line is directly additive to relief setting. That is why Summit states must go directly to tank.

 

[rScotty]

I don't know the flow of the YM2310, but 11 gpm sounds a bit too high for that size tractor.

I think that the YM2310 is similar to the US model YM276. Both use the same 3T84H engine set up to produce roughtly the same HP. In the US version the hydraulic flows 8.2 gpm at 2600 RPM. With that type of pump, flow rate is linear with RPM. If you run in the 1500 to 1800 RPM range with the FEL, you have something like 2/3 of 8 gallons or maybe 5.25 gallons/minute.

Look at how a flow divider works and you will see that it doesn't directly measure flow rate. It is using pressure and force to do what it does. Priority flow dividers work better at the upper part of their range.
Oldnslo says, "challenge". That's succinct.
Bottom line is: I doubt that the 30 gpm divider working at the bottom of its range has enough resolution to do what you want. It will do something...but I'm not sure what.

You might be better for something so critical as steering to use a proportional divider instead of a priority flow divider. It's worth a look. Take a look at the one Yanmar used as OEM in their tractors. It was sized for that very pump you have. If I remember right, the YANMAR hydraulic shop manual has a couple of pages explaining their divider. Maybe you could buy one....?

On Summit: Relief valves are typically plumbed to the sump, the hydralic reservoir tank. They rely on having very low back pressure. There is probably some exception, but I've never seen it.
Keep on it,
rScotty

 

[etpm]

I'm confused. I'm told I need a priority flow divider with a relief valve. So part of the flow goes to the steering and the rest goes to the FEL and 3PH. But what's the point of a priority flow divider with a relief valve if the excess flow must go directly to the tank in order for the relief to work? Then how am I supposed to power everything downstream from the priority flow divider and the power steering cylinder?
I guess I was way off in what I thought my pump put out. I have seen priority flow dividers that are 11 GPM max somewhere. I will need to buy one of those. If it will even work. I haven't seen any 8 GPM max ones.
Thanks,
Eric

 

[etpm]

Well, I can't seem to find a divider with 11 GPM max flow. I found several rated 16 GPM max. I guess that's what I will need to get. Summit has conflicting info on their site. Looking at the 16 GPM model it says it can be used to power another function then lower down it says the ex port must be plumbed to a tank for the relief valve to work. I think it is just bad copywriting. Whoever is writing their copy doesn't understand what they are writing about and whoever is supplying the info isn't providing clear info. Which leads to confused and frustrated customers.
Eric