Hydraulic problem

[Knight]

I just completed my grapple install. I used a 12 volt solenoid open center, spring centering valve mounted on a DO3 sub-plate. The grapple drifts rapidly down as soon as power is removed. If I quick disconnect the cylinder, you cannot move the grapple, so I would say cylinder is fine. Could air in the system cause this? I tried to cycle the cylinder a few times to remove air. Does it sound like a bad electric valve.( maybe dirt)
Is there something I am missing?

 

[kennyd]

Welcome to TBN

Can you provide a link and/or a part number for the valve you used? I suspect it's a motor control valve and the work ports are not "blocked in neutral"

 

[Knight]

Thank you for the welcome. Maybe I selected the wrong valve. There is another valve that is similar. Here is the link to the valve.

Northman Fluid Power Hydraulic Directional Control Valve 16.8 GPM, 4500 PSI, 3-Position, Double Solenoid, Open Center Spool, 12 Volt DC Solenoids, Model# SWH-G02-C3-D12-10


Power Solenoid | Valves | Hydraulics | Northern Tool + Equipment

 

[kennyd]

OK, here is direct link to that valve: CLICK HERE

From the description:

As a spring-centered valve, it will remain in its home position with all-ports commonly connected until shifted electrically to one of two positions to either extend or retract a cylinder, returning to home when the power is removed.

This is the wrong valve. You need the work ports blocked in neutral, and these are open thus letting the fluid escape the cylinder. This valve would be used for a motor but their description is sure misleading saying it can used for DA cylinders.

Edit at 4:33 EST in case you read my reply! I linked a closed center valve!

I actually can't find one on the N T&E site that looks like the right one, I looked at them all!

Take a look at THIS valve from the Surplus Center, notice the "work ports blocked in neutral" in the description-that is what you need.

 

[Knight]

kennyd

You have been a huge help to me. Thank you and have a Merry Christmas!

I will post a picture of my grapple soon. It is different in the way it stays on the loader arms and not the bucket. It can be used with forks or bucket.

 

[kennyd]

Your welcome

Please do post pictures of that grapple, it sounds very interesting!

 

[Knight]

Northman Fluid Power Hydraulic Directional Control Valve – 10.7 GPM, 4500 PSI, 3-Position, Double Solenoid, Tandem Center Spool, 12 Volt DC Solenoids, Model# SWH-G02-C6-D12-10 | Power Solenoid | Northern Tool + Equipment

The c6 looks like the valve I need.

 

[kennyd]

Northman Fluid Power Hydraulic Directional Control Valve 10.7 GPM, 4500 PSI, 3-Position, Double Solenoid, Tandem Center Spool, 12 Volt DC Solenoids, Model# SWH-G02-C6-D12-10 | Power Solenoid | Northern Tool + Equipment

The c6 looks like the valve I need.

I am not 100% sure-it never says the work ports are blocked. Maybe you could check with the manufacturer?

Can you just return the one you have and get the one I linked? You already have the DO3 plate plumbed so the swap will be easy...

 

[Knight]

I called Northman today. This is what they recommended. I like the way electrical connects. It looks cleaner than hirshman connectors. We'll see when it arrives.

c6 has a diagram, but I don't know how to read it completely.
http://www.northmanfp.com/pdf/DCVSpools.pdf

What does Tandem center mean?
TANDEM CENTER VALVES
Tandem center valves when in a neutral position by passes the flow of hydraulic oil to the return line. This is used to hold the cylinder/piston in position with no load on the pumps. When this system is the pump is running constantly to keep a ready supply of hydraulic oil, but as long as the cylinder/piston is not in operation the pump is working under no pressure or load. This system keeps wear and tear on the pump down to a minimum.

OPEN CENTER VALVES
Open center valves are the same as the tandem center, except that in the neutral position all lines are connected back to the reservoir. The primary use of this system is to prevent "shock" loading when the valve is placed in neutral. This takes pressure off the motor. This system is used in situations where the operating device needs to be moved by hand.

 

[kennyd]

Excellent! Please don't forget those pictures