pressure relief ?

[bandaidmd]

Just wondering about this and would like some opinions.
I installed a loader valve in between the factory loader and 3ph (power beyond ) as a rear remote controller.
The new loader valve has its own adjustable pressure relief, If this was set lower than the tractors system would the tractor relief now pop off at that pressure or does it only affect what i have hooked to the ports in the new valve.

 

[J_J]

You now have three valves with relief settings.

They all should be set the same.

Say the FEl is set to 2700 psi, and will protect components in that circuit.

The mid valve is set to 2500 psi and will protect components in that circuit.

The 3pt is set to 2700 psi and will pop off if the load dictates..

If you install a hyd gage in a tee in the IN port of the first valve, you will see the pressure for the component using the hyd.

 

[bandaidmd]

thanks,
I can see where ideally they would all be set to the max setting that the tractor is spec'd for but the way you describe it they are all 3 going to be independent of each other,and one being set lower wouldn't alter the load capacity on the other 2?

 

[medic0648]

If they are in series the first valve would pop off at 2700, the middle at 2500, and the 3pt would pop off the middle at 2500.

 

[J_J]

This is just a closed center schematic to show the relief valve across the main line. Each valve in an open center circuit usually has a relief.

The relief will pop off at the lowest set pressure.

Any valve downstream of the relief will go off at the lowest set pressure.

If relief settings were set lowest in the first valve, the relief set higher downstream would never go off, and the circuit would relieve at the lowest pressure..

On work port relief, the cyl or motors would use the relief set by the work port relief.

If you wanted to protect the pump under any condition, you would put a relief valve across the pump pressure line to tank.

When you get a basic tractor with no attachments, it has one relief usually at the 3pt and/or at the hyd block. As you add valves, the first valve is series should be set to protect the pump pressure.

 

[bandaidmd]

If they are in series the first valve would pop off at 2700, the middle at 2500, and the 3pt would pop off the middle at 2500.

Since my open center valves are in series and my system flows pump to loader, loader to aux, aux to 3ph. your opinion is that if the aux valve was set lower than the 3ph the 3ph would relive itself at the aux's pressure setting.

If thats the case I really need to fab up a tester rig and check them.
once again thanks to you and JJ

 

[J_J]

The safe thing to do would be to set them all the same, unless you had a hyd circuit with 2500 psi cyl, and the other cyl were 3000 psi cyl.

Then you could set that circuit to 2500 psi, but you would also affect the downstream valves.

You can make these up for about $30.