Hydraulic problem

[3RRL]

I used a similar looking Hyvair valve when doing my first installation on my Kama.
I used the Surplus Center Vickers valve when doing my wife's installation because it was a lot cheaper (at the time) and does the same thing as the Hyvair valve but requires the Hirshman connectors like you said. I see that Norhtman valve is just like my Hyvair valve and would have used it if I knew about it.
That's a very good price for that valve.

 

[Knight]

I don't understand the difference....tandem or open???

What concerns me is ........what happens when I operate this electric cylinder, will I still be able to move a down stream cylinder. Will P and T still be open when this valve is moved?

 

[kennyd]

I don't understand the difference....tandem or open???

It IS very confusing...

I just copied this from a google search of "tanden center hydraulic valve":
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.

CLOSED CENTER VALVES
This type of valve is used in a hydraulic system where the valve blocks the flow of oil from the pump into an accumulator. The accumulator (see below) is used to store the oil under pressure. This valve takes the pressure off the pump and in neutral locks the cylinder in place with no load on the pump.

So to me it appears to be different terminology for the same thing...Tandem Center is what you want by this description.

what happens when I operate this electric cylinder, will I still be able to move a down stream cylinder. Will P and T still be open when this valve is moved?

Yes, it will be fine because your cylinder cannot take the full flow of the pressure port, so the rest will flow through.

 

[Knight]

Somewhere along the way I picked up the term "open center" as opposed to some other machines having "closed center" valves and decided this is what I needed...live and learn.

I also found a good explanation here.

CHAPTER 10: Directional Control Valves, part 3

Thanks for the help.....back to installing Christmas lights before my wife catches me

 

[kennyd]

I learned something new also...
I have been using the term "open center" also for years while recommending valves, I guess the "proper" term is "tandem center"