Question about connecting another valve block in series

[bigdeano]

I have a large Cross single spool valve without PB which I've hooked in series in front of my other valve block. It's going to run a hydraulic motor eventually. It works fine at 2000psi. The metal around the OUT port is just as thick as around the IN port, so I couldn't see why it wouldn't work. I have a separate pressure relief so it won't matter if that part of it doesn't function.

To answer Tractor Seabee's question, JJ passed away some time ago if I remember correctly. We miss his wisdom.

 

[Texasmark]

To answer Tractor Seabee's question, JJ passed away some time ago if I remember correctly. We miss his wisdom.

Sorry to hear that. Was wondering why we didn't have his inputs any longer.

On my comment about teeing inputs, I guess I was thinking about a closed center system, like my JD 4020 had when I teed off the main hyd line to feed my Cross Closed Center dual remote for my FEL I added. I agree that if in parallel, the one that's not doing work will be getting all the fluid.

 

[szzuf]

Here is a pic of the hydraulic schematic for the Terex 51-19m. Can anyone tell from this if the valve block is open center? Thanks

 

[szzuf]

I did find a shop manual for this machine but it isn't showing me any PB port. That was the first thing I was looking for but I have found nothing in the manuals (parts, owners and shop) or on the block itself. There is another port right next to the supply port. It runs to a pressure relief and accumulator.

 

[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

I think you are missing the point of why I posted the schematic.

It is wrong, wrong wrong!!!

There is no power beyond feature and the out port on one valve is being used to feed a downstream valve.

This is how owner's get mislead into thinking this hydraulic stuff is easy and simple,

Dave M7040

 

[Dave M7040]

Here is a pic of the hydraulic schematic for the Terex 51-19m. Can anyone tell from this if the valve block is open center? Thanks

View attachment 545457

I see two pumps. A gear pump and an axial piston pump.

The gear pump seems to be for the simple things like the power steering. Its part of the hydraulic circuit would be open center.

An axial piston pump is one which can change its output from zero to full flow at the same engine rpm.

This more complex form of pump is used in closed center systems as it does not need to be always moving oil as it can reduce its output to zero.

This article will give you a better understanding of axial pumps.

Axial piston pump - Wikipedia

Dave M7040

 

[szzuf]

I understand the different pumps. The axial piston pump is used to run the hydrostatic tranny. I'm looking into the gear pump and how to hook into it. I wasn't sure if I could just hook in "down stream" and be able to divert the flow back to the pounder attachment or not.

 

[Dave M7040]

I understand the different pumps. The axial piston pump is used to run the hydrostatic tranny. I'm looking into the gear pump and how to hook into it. I wasn't sure if I could just hook in "down stream" and be able to divert the flow back to the pounder attachment or not.

If only it were that simple.
You need to get a valve with power beyond in the circuit.
Hydraulic valves are not designed to accept high pressure on their return or tank ports.
The valve literature for any valve clearly states this as this literature I marked up shows.

The power beyond port can accept 3,000 psi but the return or tank port only 500.

If you feed a new valve downstream using the tank line, when you activate the new valve and send pressure to a pounder, now the pressure increases in the tank line up to the relief valve setting at the pump which will be many times the acceptable 500 psi.

I don't have your hydraulic schematic in front of me as I type this post but I think the gear pump is primarily for your steering system.
Because of the risks involved in me giving you advice and one of us not understanding things completely and you loose steering at a critical point, I strongly suggest you go to either the telehandler company or a reputable hydraulic shop.

This is not a project for someone learning hydraulics.
Sorry.

Dave M7040

 

[Xfaxman]

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.

-------------------------.

Need pictures please. Does it have a 3 point hitch on the rear?

I couldn't find any info on a Wrang post pounder to see how it mounted.

 

[szzuf]

Thanks for the input guys. I see the wisdom in giving this hydraulic system more respect. I'm going to call a dealership and talk with the service guys to start with.

The website for my pounder is wrag.co.uk Mine is the Opus model.

Thanks again