Help me with Control Valve question-Please

[waldersha]

Read several threads on here, but starting to swim a little bit with terminology and what we really need.

My dad has an old Allis (WD45) that he is trying to make work with a Vermeer 605C hay baler. The baler has hydraulic twine control. The tractor itself has one way hydraulic power (power up, gravity down). We've used a control valve in the past with a different baler to run it, (lift gate in the back to drop hay bale out). There is only one hydraulic connector on it now, we need to get to 4.

I think what we need is a 2 spool valve with closed centers? So it would have 4 connectors, 2 for the lift gate (one up, one down) and the other 2 (2nd handle) for the twine control. Does all this sound correct? The lift gate side would need to remain tight while the twine is being put on. That's why I was thinking closed center.

I appreciate any help that you guys can provide. I was charged with figuring out how to make it work, Dad doesn't want to have to use a pull rope to run the twine on the bale anymore.

Thanks

 

[AKKAMAAN]

I think what we need is a 2 spool valve with closed centers? So it would have 4 connectors, 2 for the lift gate (one up, one down) and the other 2 (2nd handle) for the twine control. Does all this sound correct? The lift gate side would need to remain tight while the twine is being put on. That's why I was thinking closed center.

Closed center or open center valve, is a matter of what type of pump system you have....Closed Center, CC, valves are used in Constant Pressure, CP, system with variable displacement pumps....Valves shall be hooked up parallel...

And Open Center, OC, valves are used in Constant Flow, CF, systems with fixed displacement pumps (type std gear pump)....Valves shall be hooked up in series..

Most likely you have a CF system with a OC valve......to add more valves you need your current valve to be Power Beyond, PB, capable. That way you can add another valve down stream the current valve.

Make sure what type of pump system you have before buying valves....:thumbsup:

 

[waldersha]

I believe that you are right. Seems like a constant flow system rather than constant pressure. It is either on or off, controlled by a lever by the steering wheel.

Right now there is no valve at all. The tractor has a standard hydraulic connect on the rear. In the past, we've connected to that, and then into whatever valve.

The rest of what you said is pretty Greek to me right now. I'm looking for more info on the hydraulic system to hopefully help me help you answer my questions.

Thanks!

 

[dcyrilc]

I believe that you are right. Seems like a constant flow system rather than constant pressure. It is either on or off, controlled by a lever by the steering wheel.

Right now there is no valve at all. The tractor has a standard hydraulic connect on the rear. In the past, we've connected to that, and then into whatever valve.

The rest of what you said is pretty Greek to me right now. I'm looking for more info on the hydraulic system to hopefully help me help you answer my questions.

Thanks!

The WD45 was built from '53 to '57. There is a very good chance that it is a Closed Center hydraulic system.

I have to agree with AKKAMAAN that you need to make sure which type of hydraulic system you have before buying valves.

 

[waldersha]

Any suggestions on how to do that? I am striking out trying to find anything online.

 

[waldersha]

Ok, about the only thing that I can find on it says that the hydraulics are closed center in standard form. Does that help with my other questions?

 

[beenthere]

Have you thought about adding a pump off the engine, and a valve bank to get what you want?

 

[waldersha]

No I haven't. I'm pretty sure that it can work as is, just need the right control valve. Not really interested in adding parts and $ if we don't need to. Shouldn't take much to run the twine part of the baler.

 

[dcyrilc]

Ok, about the only thing that I can find on it says that the hydraulics are closed center in standard form. Does that help with my other questions?

It does. We now know that you will need valves which are Closed Center.

I think what we need is a 2 spool valve with closed centers? So it would have 4 connectors, 2 for the lift gate (one up, one down) and the other 2 (2nd handle) for the twine control. Does all this sound correct? The lift gate side would need to remain tight while the twine is being put on. That's why I was thinking closed center.

Open and Closed Center valves control hydraulics in the same manor. The difference is determined by the pump and they cannot be crossed.

A Closed Center, 2 spool valve would be correct for your needs. The spool for the lift gate sounds like it will need to be double acting. Not sure about the twine control. There's also a term for it returning to neutral when not being activated. AKKAMAAN, Kennyd, or others will be able to give you the correct terminology for that. My mind's drawing a blank right now. You will also need to determine where the return for the hydraulic fluid will return to the hydraulic resivoir.

 

[waldersha]

It does. We now know that you will need valves which are Closed Center.



Open and Closed Center valves control hydraulics in the same manor. The difference is determined by the pump and they cannot be crossed.

A Closed Center, 2 spool valve would be correct for your needs. The spool for the lift gate sounds like it will need to be double acting. Not sure about the twine control. There's also a term for it returning to neutral when not being activated. AKKAMAAN, Kennyd, or others will be able to give you the correct terminology for that. My mind's drawing a blank right now. You will also need to determine where the return for the hydraulic fluid will return to the hydraulic resivoir.

Perfect. Thank you for your help. So definately a 2 spool closed center valve.
Returning to neutral when not being activated. . . that doesn't mean that the lift gate would be able to float does it? It has to stay locked down so the bale doesn't get sloppy (pressure on from cylinders)

The fill tube for the hydraulic pump is plumbed for a return, so that shouldn't be an issue.

The twine control also has a 2-way cylinder, just btw.
Thanks again for your help. Gets me looking in the right direction.

 

[George G]

I think you better go here to ask your ?Allis Chalmers Discussion Board. If I'm right, a WD-45 has an open center system. Runs between 3300 & 3700 psi, puts out a little less than 3 gpm, and the reservoir holds about 6 qt's of oil

 

[waldersha]

So one like this one would be correct? https://www.surpluscenter.com/item.asp?item=9-7862&catname=hydraulic

The system itself is pretty low flow (I think 4GPM or so) so Seems like this one would handle it, and I think 2000 psi is about right too. It says it has a plug to convert to closed center, is that sufficient?

Any opinion on Prince versus Cross versus??? I've only ever really been around Cross valves.

Thanks!

 

[waldersha]

Thanks George. I found the information that I was using on the "unofficial" Official Allis page. Different information on your link (7GPM, 3000 PSI) but no mention yet of open or closed center. I'll keep looking.

 

[George G]

The Service Manual refers to the pump as a Variable pump. The pump unloads when it reaches max psi(3300-3700 psi). So! I would say, you would treat it like a closed system.

 

[waldersha]

The Service Manual refers to the pump as a Variable pump. The pump unloads when it reaches max psi(3300-3700 psi). So! I would say, you would treat it like a closed system.

Arrrgh!!! :confused2: Thanks George. So then it would be like a closed center system needing closed center spool valves?

Is the one I linked to above correct then?

Thanks!

On Edit, asked the question over at YT as suggested. Got a response that I need open center, but nothing else as far as explanation. The valve linked above is open center with a plug for converting to closed. Is it as simple as hook it up one way and if it doesn't work try the other? Don't want to hurt anything, but there is so much conflicting information that I'm not sure what to believe.

 

[dcyrilc]

Perfect. Thank you for your help. So definately a 2 spool closed center valve.
Returning to neutral when not being activated. . . that doesn't mean that the lift gate would be able to float does it? It has to stay locked down so the bale doesn't get sloppy (pressure on from cylinders)

The fill tube for the hydraulic pump is plumbed for a return, so that shouldn't be an issue.

The twine control also has a 2-way cylinder, just btw.
Thanks again for your help. Gets me looking in the right direction.

No, it means that the control handle on the valve will return to the neutral/centered position if you let go of it. Otherwise, it would continue to move the ramp until you manually centered the valve handle. When the valve handle in is the neutral/centered position, the cylinder will be locked in its current position.

As for the twine cylinder, if it's a 2 way cyclinder, it also would use a DA spool. A Single Acting (SA) Cylinder will only have one hose for hydraulic fluid and a Double Acting (DA) Cylinder will have two hose connections (one on each end).

 

[dcyrilc]

Arrrgh!!! :confused2: Thanks George. So then it would be like a closed center system needing closed center spool valves?

Is the one I linked to above correct then?

Thanks!

On Edit, asked the question over at YT as suggested. Got a response that I need open center, but nothing else as far as explanation. The valve linked above is open center with a plug for converting to closed. Is it as simple as hook it up one way and if it doesn't work try the other? Don't want to hurt anything, but there is so much conflicting information that I'm not sure what to believe.

So far, it looks like your biggest chalange is going to be determining if you have an OC or CC system.

Here is the basic difference between the systems. On a Closed Center system, no fluid passes through the valve when it is in the centered/neutral position (the valve is closed between the input and return ports) and when the pump reaches operating pressure, it ceases to create pressure or pump fluid beyond what is needed to maintain pressure (this is why it is also known as a Constant Pressure (CP) system). On an Open Center system, fluid passes freely through the valve to the return line when it is in the centered/neutral position (the valve is open between the input and return ports) and the pump always pumps fluid (this is why it is also known as a Constant Flow (CF) system. Using a CC/CP valve on an OC/CF system will put the pump into relief (over-pressure state) because the fluid has no where to go. On the other hand, using an OC/CF valve on a CC/CP system will over work the pump as it is not designed for continous full operation as well as there may be issues from lack of pressure to operate the cylinders.

 

[dcyrilc]

On Edit, asked the question over at YT as suggested. Got a response that I need open center, but nothing else as far as explanation. The valve linked above is open center with a plug for converting to closed. Is it as simple as hook it up one way and if it doesn't work try the other? Don't want to hurt anything, but there is so much conflicting information that I'm not sure what to believe.

Almost all new tractors these days are OC/CF systems due to lower construction costs (unless you get into the larger tractors). Because of this, many people simply default to this if they are not familiar with the system.

Many of the older tractors had CC/CP systems which is why I expect to find it to be CC/CP.

 

[David Devuono]

Interesting discussion that has me real confused. In my case I am starting from scratch, building a small tracked ride on dumper. I am told I need an open centre valve for the drive motors. Looking at pumps, I have not heard information about whether there are open centre system pumps and closed centre system pumps. Now I am wondering if the pump I have will work for my installation. Don't answer here, I will start a new thread.

Dave

 

[waldersha]

Almost all new tractors these days are OC/CF systems due to lower construction costs (unless you get into the larger tractors). Because of this, many people simply default to this if they are not familiar with the system.

Many of the older tractors had CC/CP systems which is why I expect to find it to be CC/CP.

I asked dad and he said that it is a CP system. So that being said does the valve I linked to earlier make sense?

https://www.surpluscenter.com/item.a...name=hydraulic