Question about connecting another valve block in series

[szzuf]

Hi

I own a 2002 Terex 51-19m compact telehander. It has a gear pump off the timing chain that feeds the steering motor first through a priority valve and then the pilot operated valve block for the boom. I'm planning on mounting a Wrag post pounder on the rear which needs a suction and return line. I will be leaving the pounder mounted on the machine so I'm thinking about just running back a dedicated live line to the pounder and it's own return line to the tank. I cannot find a power beyond port on the block but am wondering if I can just tee in after the block on the return to the tank before the check valve. It looks to me like center is open on the valve block. I also wouldn't be using the boom and the pounder at the same time so I'm not worried about both not working at the same time.

My older and wiser brother said I should ask the professionals so asking is in progress. Thanks for all your help.

I have a picture of the hydraulic schematic but am having trouble loading the page. I'll keep working on it.

 

[Texasmark]

If you are using "open cylinder" systems you an connect as many as you desire in series. Flow will return to the sump until you move any of the controls to the "divert" position.....first one in line has priority....aka only one is operable at a time. If dual usage requirement, then plumb at the input to the first in line and parallel plumb over to the aux valve. Then you can have both running at something less than full available (from your tractor's hyd. pump) volume. Returns can all be summed together and returned to the sump.

 

[szzuf]

Great. That is what I thought but better be safe and ask others. Thanks

 

[oldnslo]

If you are using "open cylinder" systems you an connect as many as you desire in series.

This is true IF the valves have the capability of having full system pressure on the tank ports. You would have to verify in the existing pilot operated valves can handle full system pressure on the tank ports.

 

[Tractor Seabee]

You need to check with a dealer shop on whether your machine's existing valve has a Power Beyond (PB) port and the special plug usually installed to activate the PB function. That outlet becomes the Power Supply (P) for the next valve in the series; and on and on. You can tee into the return line to the tank/sump (T). All valves in the same stack enjoy a common T connection. Try to get a shop manual for your machine if doing your own mechanic work. It would also have this information.

Ron

 

[Dave M7040]

Hi

I own a 2002 Terex 51-19m compact telehander. It has a gear pump off the timing chain that feeds the steering motor first through a priority valve and then the pilot operated valve block for the boom. I'm planning on mounting a Wrag post pounder on the rear which needs a suction and return line. I will be leaving the pounder mounted on the machine so I'm thinking about just running back a dedicated live line to the pounder and it's own return line to the tank. I cannot find a power beyond port on the block but am wondering if I can just tee in after the block on the return to the tank before the check valve. It looks to me like center is open on the valve block. I also wouldn't be using the boom and the pounder at the same time so I'm not worried about both not working at the same time.

My older and wiser brother said I should ask the professionals so asking is in progress. Thanks for all your help.

I have a picture of the hydraulic schematic but am having trouble loading the page. I'll keep working on it.

You need to be very careful as this marked up valve spec shows.

The tank or return port is only rated for 500 psi so if you have another valve which this port is supplying and you activate the new valve to operate almost anything the pressure in the line will spike well beyond 500 psi likely breaking the main valve.

Dave M7040

 

[Texasmark]

You need to be very careful as this marked up valve spec shows.

The tank or return port is only rated for 500 psi so if you have another valve which this port is supplying and you activate the new valve to operate almost anything the pressure in the line will spike well beyond 500 psi likely breaking the main valve.

Dave M7040

Good point. If I could find my Cross Open Center spec I'd see what it says. Guess it depends how the spool seals and flow routing work on the particular pump.

My Fords use an open center system and in the hyd line from the pump to the lift cylinder you can remove a cap on top of the hyd sump casting and insert a plate with a flow through port for a remote valve.

IF the 3 pt is all the way down, there is no "tank pressure" per se...a few psi. If the 3 pt is in the lift position and lifting, whatever pressure is required, to the maximum capacity of the pump at that rpm, to accomplish the lifting is present on the inlet and outlet of the aftermarket remote valve. In this case In and Out ports would have to be rated for the max pressures. Been using the Cross valves (from TSC) for 40 years and never had a problem plumbed as such.

Flip side is Tee at the source and you don't have to worry about it.

 

[Dave M7040]

Good point. If I could find my Cross Open Center spec I'd see what it says. Guess it depends how the spool seals and flow routing work on the particular pump.

My Fords use an open center system and in the hyd line from the pump to the lift cylinder you can remove a cap on top of the hyd sump casting and insert a plate with a flow through port for a remote valve.

IF the 3 pt is all the way down, there is no "tank pressure" per se...a few psi. If the 3 pt is in the lift position and lifting, whatever pressure is required, to the maximum capacity of the pump at that rpm, to accomplish the lifting is present on the inlet and outlet of the aftermarket remote valve. In this case In and Out ports would have to be rated for the max pressures. Been using the Cross valves (from TSC) for 40 years and never had a problem plumbed as such.

Flip side is Tee at the source and you don't have to worry about it.

I am not trying to argue so plse don't misinterpret my post.

I am not a hydraulic expert like form member JJ who is a genius with these systems.

Small Kubota's like a B7100 have an optional hydraulic block you need in order to add another circuit.

In this Kubota hydraulic block you essentially have a selector valve where you can run one circuit or the other but not both

This photo was posted by a tractor owner after he realized he had not connected his new valve properly.

Unless you are using a true hydraulic flow divider, you cannot just Tee off the pump output on an open center system as the pressure will take the path of least resistance which will be through the parallel circuit which is not being used and the flow will just return to the tank with no pressure available to use.

This next image was taken from the web site of a supplier of parts for Chinese tractors. It is a bad design as it uses the tank port or return port of one valve to feed the next.
It is because of this junk information that many owners believe the addition of another hydraulic circuit is simple.

I went to the CROSS hydraulic's web site.

This paragraph is typical regarding the tank ports on their valves.

In a valve rated for 310 bar or 4,500 psi, the tank port is limited to 70 Bar or 1,015 psi.
The tank port is capable of handling 22% of the pressure the valve is designed for

A-B Lateral Ports, P-T Rear Ports c/w Relief Valve. Modular (Sandwich) Valve. Stock No. Symbol. Description. Cetop *. Flow. Pressure. List Price. LC04VRAB ... CROSS. Cam Operated - Max. flow 70 l/min, max. pressure 310 bar, max. tank line back pressure 70 bar). Stock No. Symbol. Description.

The old Massey tractors such as a 135 or 165 had very complex hydraulic systems for their time.

Your thoughts or comments on the above most welcome.

Dave M7040

 

[Tractor Seabee]

Basics: 1. The open center valves have to have the Power Beyond (PB) plug installed to get power to the next valve through its PB port.
2. Flow is always from; first user gets power (P) line from the pump, then the PB port of that valve feeds the power port on the next.
You can add more valves as long as you maintain the P and PB relationship. A valve is one or a stack of several in a block.
3. The tank port of each valve goes back to the tank/sump (this line has minimal pressure unless blocked somewhere.
4. Best to tee the T line at the tank connection not somewhere in the line (potential for back pressure)
5. be sure to use all forged steel fittings and connectors rated for hydraulic pressures and stay away from Teflon tape.

Closed center valve arrangements are totally different.

I don't profess to be an expert like JJ. I have learned by working with my BX and poring over the hyd drawings in the WSM and some reading of hyd manuals. I used to read JJ's posts religiously. Where is he by the way?

 

[Tractor Seabee]

I am not trying to argue so plse don't misinterpret my post.

I am not a hydraulic expert like form member JJ who is a genius with these systems.

Small Kubota's like a B7100 have an optional hydraulic block you need in order to add another circuit.

In this Kubota hydraulic block you essentially have a selector valve where you can run one circuit or the other but not both

This photo was posted by a tractor owner after he realized he had not connected his new valve properly.

Unless you are using a true hydraulic flow divider, you cannot just Tee off the pump output on an open center system as the pressure will take the path of least resistance which will be through the parallel circuit which is not being used and the flow will just return to the tank with no pressure available to use.

This next image was taken from the web site of a supplier of parts for Chinese tractors. It is a bad design as it uses the tank port or return port of one valve to feed the next.
It is because of this junk information that many owners believe the addition of another hydraulic circuit is simple.

I went to the CROSS hydraulic's web site.

This paragraph is typical regarding the tank ports on their valves.

In a valve rated for 310 bar or 4,500 psi, the tank port is limited to 70 Bar or 1,015 psi.
The tank port is capable of handling 22% of the pressure the valve is designed for

A-B Lateral Ports, P-T Rear Ports c/w Relief Valve. Modular (Sandwich) Valve. Stock No. Symbol. Description. Cetop *. Flow. Pressure. List Price. LC04VRAB ... CROSS. Cam Operated - Max. flow 70 l/min, max. pressure 310 bar, max. tank line back pressure 70 bar). Stock No. Symbol. Description.

The old Massey tractors such as a 135 or 165 had very complex hydraulic systems for their time.

Your thoughts or comments on the above most welcome.

Dave M7040

How does the used fluid get back to the tank (T)? Is this system a power beyond (PB) type? The diagram seems to be missing some pieces and proper terminology. I assume "out" is really the PB continuation of the fluid to the next valve.

Ron