Converting a double acting valve for use with single acting cylinder?

[Verticaltrx]

I'm working on building a post driver and I need a single acting hydraulic valve to raise and drop the weight. I bought a 'converta-valve' from Tractor Supply that I think will do what I need, but there are no instructions with it. The valve is a Chief Model 220940 single spool valve, says "3 or 4 Way w/conversion".

It came with no instructions and there are none to be found on the web as far as I can find. Below is a picture of the valve:



Obviously the two connections on top are for the cylinder (one of which I will plug), and I think the one labeled "P" is for the pressure side. What about the other two ports? For a single acting setup what should be hooked up to what on this valve? Any insight would be great, thanks in advance.

 

[J_J]

P is the input flow

T is tank flow.

If you will use a SA cyl, then use A port for the cyl supply.

Either plug the B port or run the B port hose to tank.

Don't know what the N is, but could be the carry over port.

Are you going to use something for tilt, front to back and left/right?

What did you pay for that valve?

Here is a valve with PB in case you need to add valve downstream.

http://www.surpluscenter.com/Hydrau...OOL-8-GPM-PRINCE-MB11B5C1-DA-VALVE-9-7861.axd

http://www.surpluscenter.com/_MoreSpecs/iPrinceMBValves.pdf

 

[Verticaltrx]

What I'm worried about is if the valve is in double acting mode and I plug port B (they aren't labeled, I'm assuming you mean one of the two center ports) is that the pump will be trying to force fluid against the plug as the other side is lowering. I know on some of our tractors with dual rear remotes only one of the remotes is capable of running a SA cylinder. If you put it on the wrong one it makes the relief valve squeal when you are lowering the load.

I'm wondering if maybe you use either port "T" or port "N" depending on if you are using it for a SA or DA cylinder? Maybe there was another conversion part that was missing from the box? (which had been opened)

I have another 2-spool valve that will control the tilt. It has power-beyond and will feed this Chief valve. I'm putting this one last in the series so I can run a big return line to the tractor hydraulic reservoir with minimal restriction.

 

[J_J]

You are right about plugging the B port as the relief will squeal, so just run the B port to tank.

You could also use B port for supply and run A port to tank. Depending on which way you want the lever to work.

I would only go one size up on the hose to tank.

 

[Winmac]

It might be best to ask tractor supply for instructions, rather than guessing.
Was there a conversion adapter included?

 

[Verticaltrx]

So I called several Tractor supply stores and asked them to look in a new unopened box for this valve. Not one of them came with instructions, they did however come with two plugs which I did not get. All I got was the valve as shown and a handle. I'm going to pull out plug "T" and see whats inside...

 

[J_J]

You might try some air in the P port and see what you get at the N port and the tank port. Try the work ports also and see if the valve will do what you want.

I have never seen the N designation before.

 

[Verticaltrx]

Here is the plug that was in port "T":



The lower portion blocks a hole into the other work port.


Here is a pic of what it looks like inside port "T":



That little hole goes into the port directly above it, we'll call that port A. I'm thinking I'll put a plug in port A, hook my cylinder to port B (the one right beside it), and put a standard plug in port "T" instead of the original one. That should provide a means for the fluid to escape when lowering the load, right?

Edit: "N" and "T" are in the same cavity, which is the return side of the valve.

 

[J_J]

That looks like a closed center plug.

If you are not going to use PB, then you need to just add a plug in the PB port.

Once you install the plug, use air to verify where the flow is going.

In neutral, air should go from IN port to TANK port.

When you push the lever, air should flow through the valve and come out one of the work ports. Pull the lever, and air will come out the other work ports.

So what happens with a DA cyl is that fluid flows out of the valve into a cyl port, and the other port on the cyl is pushing fluid back to the valves other work port and then through the OUT port to tank.

So, now using the valve as an SA valve, and an SA cyl, you are feeding fluid to the base end of the cyl to extend the rod, and then you pull the lever back which will feed fluid into the B work port and that fluid goes to tank, and the fluid in the cyl will flow back out the same port it went in and then to tank.

Hope I have not confused you, but that is how it works.

Two addition. The tank port is never plugged, so someones been messing with that valve.

With the PB port plugged, all fluid , both pump flow and cyl expended fluid will pass through the OUT port to tank.

 

[Elder Massey]

I too belong to the list of people who have purchased this "convertible" valve. Many others have posted the same basic questions. If you turn this POS upside down it will be marked P80. It is made by Badestnost in Bulgaria and sold under various brand names. Attached is their instruction sheet.


This comes with a closed center plug in the T port for use as a 4 way double acting control and the N port is used for return. Remove it. Follow the written instructions for use as a 3 way. Plug the A port closest to the handle. Use a plain plug in port N.

Now, please do not take my word for anything. Check it with compressed air. If you want even more confusion then attempt to make sense of their block diagrams which do not show port "N" and are absolutely not representative of this control valve. There is some very confusing porting happening inside the manifold and with the spool.

Mine happens to be labeled Chief...but you will not find this in their catalog. It can be found in Grangers catalog..but they will not sell a "power beyond" sleeve except to international customers. I'll leave this to speculation, but there is only one instance that I have ever seen that would cause this....

I wrote in another post that if people are going to sell hydraulic controls, then they should provide and fully diagram all internal functions as well as all ports. This is precisely what gets people hurt. I said that I would not post again on this forum, because it is my belief and experience that if someone doesn't know exactly what they have, then it should NEVER be connected...nor should speculative assumptions be made even when good people are trying to help. I hope I have.

 

[J_J]

Thanks, your knowledge and description of the valve is appreciated.

This valve is a first for me.

It works pretty much like I said, does it not..

No body else does what they did as far as using the T port for the selection for the closed center or standard valve., and no one uses the N symbol to designate a port.

The T port and the N port share the same cavity. They chose to confuse the situation.

Like I said before, use air to determine the flow.

As far as Plugging A and use B as the work port is fine. Either work port will work. You are simple shifting a spool.

If using this valve in an open center hyd system, either the T port or the N port can be used for the OUT fluid.

As far as back pressure, the say 700 psi. That is usually stated for the tank pressure, and they usually refer to the problem with exceeding the value, is that the seals will be damaged.

PB ports have always been able to handle high pressure.

They don't show a carry over/PB port, but if this is the last valve in the system, you don't need one.

If you need PB, then I would not use this valve.

Use air to verify all functions.

 

[Elder Massey]

Right.. "they" chose to confuse the issues. A new right out of the box control valve with the T port blocked with an otherwise unidentified plug should be enough to raise red flags to anyone. This man, and several others that have asked the same questions about the tank port being blocked, combined with an again unidentified "N" port, with or without an instruction sheet, is utter nonsense. The plug had to be removed to identify it as a closed center plug. This man had to call several stores and could not get a straight answer. If something does not come with a schematic diagram of the circuit for that particular device, or it is not available anywhere else, then I personally believe that end users are senselessly put at risk. In essence, that is all that I am saying or will say.

I don't need someone distributor's lawyers breathing down my throat. Personally, when so much time has to be devoted to basically troubleshooting a brand new control valve, my opinion is that it should not be on the market and I will speculate that this is why these controls are on eBay for fifty bucks. Kind of akin to buying Chinese dogfood.

I checked mine for use as a 4 way. He should verify what the supposed "instruction" sheet says for 3 way use. While I know that I could use it as a 4 way my thoughts were about whoever has to deal with it in the future. My brand new "convertible control" is in my scrap pile behind my workshop where it will stay.

 

[glastron23]

Elder.. these are not that bad of a valve.. just a little bothersome to get info on them.. the N port is a tank port on the 3/4 valves. On a 4 way only valve it would be used as a Power beyond out port.
The 3/4 valves require that the plug 14 be installed in the T port for a 3 way valve as it allows the A port(via a drilled passage) to bleed to tank when you retract the SA cylinder. The spool will open the pump flow to the A port and this needs to go to tank to prevent the hydraulic oil from dead heading in the unused A port.
When you change it to a 4 way valve you install plug 13 in the T port that plugs the A port drilled passage and allows the A port to then direct fluid to the DA cylinder. All pump flow then exits the N port back to tank.

 

[glastron23]

trying to find the PDF's on this one, when i find them will post.