Open Center valve

[a05883]

Could someone explain what an open center remote valve is?
Thanks

 

[bcp]

From:
Hydraulic machinery - Wikipedia, the free encyclopedia

"Open center circuits use pumps which supply a continuous flow. The flow is returned to tank through the control valve's open center; that is, when the control valve is centered, it provides an open return path to tank and the fluid is not pumped to a high pressure."

Bruce

 

[a05883]

What exactly would you use that type of valve for? Could you use that to supply a backhoe?

 

[pacerron]

Could someone explain what an open center remote valve is?
Thanks

Do you have a tractor with one on it?

 

[2458n]

Yes, you can have a open center on a backhoe. I have a Arps 750 3pt hitch that uses this system. What are you trying to do? Do you know if the tractor has a pump that uses a open or closed type valve set-up.?

 

[J_J]

BH valves can be open center or closed center.

Some open center valves can be converted to closed center valve by the use of an adapter plug.

You could also switch out the valve for one that will work with your tractor.

 

[rambler]

You need to match up your valves to your tractor.

There are ways to convert from open to closed; my backhoe you can change a hose/valve and use it with open or closed center tractor.

Basically you want to use open center valves with tractors that have open center style pumps - these provide constant flow of oil at low pressure that curculates oil through all the valves, until a valve askes for oil & then the oil gets diverted to that use.

Closed center pumps provide a constant oil pressure. When you move a valve, the amount of oil flow changes from zero to whatever is needed to do something.

So - buy a valve to match your tractor (or pto pump, or whatever).

You shouldn't mix and match between the 2 types of valves, that doesn't work well. (Yes there are special cases as I mentioned, but that takes $$$$ special setups.....)

--->Paul

 

[pacerron]

What exactly would you use that type of valve for? Could you use that to supply a backhoe?

I have a Ford 3910 ( 42 PTO HP) that I have put over 3000 hours on. It has an open center remote valve supplying two remote outlets on the back of the tractor. I purchased the tractor new with a FEL . The dealer put a rubber bungy cord on the valve handle to hold it open. It was in that position the majority of the time, and is now 100% for the FEL because I have another tractor.
For many years I would use the same valve during hay seasons to run a hydraulic hay rake that could be reversed as a tedder and to operate my round baler lift gate up and down when expelling hay rolls.
So there you have some common uses for the valve. Tractors were much simpler back then but built to last.
The book says not to tie the valve open but that would be the case only if you had nothing attached to the remote as the pump would be operating against a dead head.
The valve is just a reversing gate with neutral for oil flow. Hooking a backhoe to it depends on the capacity of the system and the needs of the backhoe.
I use a backhoe that has its own PTO driven pump and oil tank for the best of both worlds on that particular tractor.
When hydraulic systems are asked to do more than their capacity that's when you see all the questions on this forum asking "why is it so slow" or "why won't it lift the wheels off the ground" etc, etc.

 

[J_J]

Open center pumps and valves are connected in series and there is no or very little pressure in the system with all levers in neutral.

Closed center valves are installed in parallel, and there is usually full pressure or a low standby pressure at the valves. Hyd pump is at idle or unloaded.

A hyd gage in a tee at the IN port of a hyd valve will usually tell you what you what hyd system you have.

To answer the original question, about the open center remote valve.

It is a valve used in an open center hyd circuit which is a series hyd circuit, and is used in a remote location for whatever. Log splitter, BH, hay baler, hyd tiller, hyd bush hog, etc.

Do you know which hyd system you have.

 

[a05883]

I believe it is an open center system. I would like to hook up my BH to the remotes instead of buying a kit from Woods if that is possible. The kit is just under $300 and if I can hook it up to my existing remotes I can save over $200.

 

[J_J]

Does your BH use two or three hoses?

Does your BH valve have a PB port?

If you have two ports, you can just plug the BH into the remote QD's.

If your BH have three hoses, run the tank port to tank.

Bungee the remote spool valve on for the BH.

You can vary the engine rpm for the hyd action you want from fast to slow.

If you want some of the cyl slow on the BH, you can use restrictors in that particular circuit.

 

[a05883]

Does your BH use two or three hoses?

Does your BH valve have a PB port?

If you have two ports, you can just plug the BH into the remote QD's.

If your BH have three hoses, run the tank port to tank.

Bungee the remote spool valve on for the BH.

You can vary the engine rpm for the hyd action you want from fast to slow.

If you want some of the cyl slow on the BH, you can use restrictors in that particular circuit.

I just checked my manual and it says my rear remote valve is an "open center series type. (Full flow detent in section one on both the A and B coupler)"
The backhoe has two hoses. So if I understand you correctly I could hook up the 2 hoses to the QD's and place the valve in detent.
I won't have to worry about the speed of the hoe as it has a valve on it to control its speed.
Thanks for your responses!

 

[N8ghz]

Depending on what GPM your tractor's rear hydraulics are...the speed control on the hoe isn't going to make the hoe any faster than whatever GPM the tractor makes...you can slow it down though...but that's all.

 

[J_J]

Just make sure you have pressure going into the IN port of the BH valve.

It will depend on the QD that you plug in as to which way the lever should detent .

Usually the BH will operate at the volume/GPM that the hyd pump is putting out.

What do you have on the BH valve to dial down the volume of the tractor hyd pump volume?

 

[pacerron]

I just checked my manual and it says my rear remote valve is an "open center series type. (Full flow detent in section one on both the A and B coupler)"
The backhoe has two hoses. So if I understand you correctly I could hook up the 2 hoses to the QD's and place the valve in detent.
I won't have to worry about the speed of the hoe as it has a valve on it to control its speed.
Thanks for your responses!

If your talking about the detent when the valve handle is in other than center position, you will probably have to tie it back to keep it from popping back to center when you work your loader valves. If you are looking at the book it should describe the valve action very simply. If not you will learn very quickly when you hook it up the wrong.

 

[J_J]

I believe he is talking about a rear remote valve, which has detents on two of the spools.

All he should have to do is to plug in correctly and detent the valve and the BH should be ready to work.

At max engine, you will be providing about 8.2 GPM to the BH. If the BH operations are too fast, just reduce the engine rpm until you can work at your chosen pace.

Hydraulics:
Type: -unknown-
Capacity: -unknown-
Pressure: -unknown-
Valves: 1 or 2
Valve flow: 8.2 gpm [31.0 lpm]
Total flow: 12.7 gpm [48.1 lpm]
Steering flow: 4.5 gpm [17.0 lpm]

 

[a05883]

JJ you are correct. I am talking about the rear remote valve.
Thanks for your patience,you've have answered my questions.
My tractor is rated at 7.9 gpm and the backhoe requires 5-7 gpm. the valve on the backhoe is a restrictor valve I think. I haven't actually received the backhoe yet. It should be here in a week or two. I'm just trying to gain information ahead of time.

 

[J_J]

On my BH, the valve itself does not have restrictors, but several of the hyd circuits in the valve have restrictors. You can vary the size to suit your purpose.

 

[pacerron]

I believe he is talking about a rear remote valve, which has detents on two of the spools.

All he should have to do is to plug in correctly and detent the valve and the BH should be ready to work.

At max engine, you will be providing about 8.2 GPM to the BH. If the BH operations are too fast, just reduce the engine rpm until you can work at your chosen pace.

Hydraulics:
Type: -unknown-
Capacity: -unknown-
Pressure: -unknown-
Valves: 1 or 2
Valve flow: 8.2 gpm [31.0 lpm]
Total flow: 12.7 gpm [48.1 lpm]
Steering flow: 4.5 gpm [17.0 lpm]

JJ
I always defer to your knowledge of hydraulics. Your the best!
I probably didn't quite understand his question. My old 3910 Ford has an open center remote valve lever right below the seat on the rear end casting that is hosed to two quick release remotes on the back. Normally my FEL is hooked to them and I need to bungy the lever to the rear position to keep it from popping back to center open when I maximize the lift arms or the bucket curl or close. It could be held forward by a bungy if I reversed the hoses to the FEL but that would be in the way. Same goes for the bale extractor door. I don't bungy it and when it is closed the valve is in center neutral position.
I plug the hoses in so when I pull the lever back the door raises. When the door gets to maximum height if I were to continue to hold the valve handle back the pump would be trying to raise the door higher than possible and groan a bit in defiance of the pressure. If I let go at that point the valve handle and valve would pop back to the center neutral but the baler door remains at maximum open. When I pull the lever forward the door closes but would stop and remain at any position if I center the valve before complete door closer. If I hold the lever forward after the door is completely closed then the pump groans to remind me to wake up. So the detents I was referring to are the ones in the forward and rear position of the handle. They automatically kick back to neutral at the end of the cyclinder strokes unless tied or held open. The detents can be removed but I have used the tractor this way for 20 years with no problems.
I would think hooking a two hose back hoe to a center open valve would work the same way as I described for my FEL.

 

[SSdoxie]

JJ
I always defer to your knowledge of hydraulics. Your the best!
I probably didn't quite understand his question. My old 3910 Ford has an open center remote valve lever right below the seat on the rear end casting that is hosed to two quick release remotes on the back. Normally my FEL is hooked to them and I need to bungy the lever to the rear position to keep it from popping back to center open when I maximize the lift arms or the bucket curl or close. It could be held forward by a bungy if I reversed the hoses to the FEL but that would be in the way. Same goes for the bale extractor door. I don't bungy it and when it is closed the valve is in center neutral position.
I plug the hoses in so when I pull the lever back the door raises. When the door gets to maximum height if I were to continue to hold the valve handle back the pump would be trying to raise the door higher than possible and groan a bit in defiance of the pressure. If I let go at that point the valve handle and valve would pop back to the center neutral but the baler door remains at maximum open. When I pull the lever forward the door closes but would stop and remain at any position if I center the valve before complete door closer. If I hold the lever forward after the door is completely closed then the pump groans to remind me to wake up. So the detents I was referring to are the ones in the forward and rear position of the handle. They automatically kick back to neutral at the end of the cyclinder strokes unless tied or held open. The detents can be removed but I have used the tractor this way for 20 years with no problems.
I would think hooking a two hose back hoe to a center open valve would work the same way as I described for my FEL.

What you have on your Ford is a detent with pressure return to neutral. This is used commonly on Ag tractors for raising & lower implements in field work. Example is pulling a wheel disc: When you come to end of the field just pull the lever into raise detent and put you hand back on throttle or steering wheel to start making your turn. The disc will raise until cylinder reaches end of its stroke & the lever will retrun to neutral, once you have turned around and starting back into the field push it into lowering detent and the cylinder will lower the disc to it's set depth then push the lever into neutral again. This removes the need to keep you hand on the lever to avoid hydraulics going over relief and overheating system while at the same time you have both hands to run throttle and steering.
I have used a IH 656 with this on it and ran a wood splitter by tying back the lever with a bungie cord, works fine if the cord is strong enough.