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.