Power beyond and tank ports

[Stomper]

Can someone please explain to me the difference between a valve with power beyond port and a valve with a tank port. I may be wrong but from my findings but power beyond ports are used when another hydraulic control valve is to be used down stream of another valve to supply hydraulic power to it. And a valve with a tank port sends the hydraulic fluid back to the tank to be pumped through the system again. What I dont understand is why cant the tank port on a hydraulic valve be used to feed the next valve in a system.
The reason I ask is, I had my local hydraulic shop source out an auto cycle log splitter valve for the fire wood processor I am building. It didnt come with power beyond but he told me his supplier told him there was another piece I could get to screw into the tank port on the valve that would give me power beyond capability with the valve. I asked him to explain but he was unsure also. Said he would find out but I havent heard from him yet.

 

[oldnslo]

Stomper
Tank ports on most mobile cast iron valves cannot be pressurized. The power beyond fittings Isolates the tank port from being pressurizes.
When using power beyond you must also have a tank connection on your valve.

Every FEL valve assembly that I have ever seen requires a separate tank line when using the power beyond to operate other functions.

 

[agjones]

Can you edit that to clarify on which valve you must 'also have a tank connection'...

 

[CincyFlyer]

Stomper
Tank ports on most mobile cast iron valves cannot be pressurized. The power beyond fittings Isolates the tank port from being pressurizes. When using power beyond you must also have a tank connection on your valve

Not necessarily. My backhoe has one hose in, and one hose out; the "out" hose is PB to the 3-point, then to the tank.

 

[oldnslo]

Cincyflyer
most Valves isolate the tank & PB. Depending on the style of valve you have it might have pressure rated tank ports.

I suspect that if you put a heavy load on the 3PH with the back hoe mounted your valve would develop external leaks.

 

[Stomper]

The valve in question has nothing to do with my tractor. It is an auto cycle log splitter valve that will be controlling the splitter cylinder on my firewood processor I am building which will have its own motor and hydraulic pump. I want power beyond to feed the valves that will control the adjustable wedge and conveyor motor.

 

[Stomper]

Stomper
Tank ports on most mobile cast iron valves cannot be pressurized. The power beyond fittings Isolates the tank port from being pressurizes.
When using power beyond you must also have a tank connection on your valve.

Every FEL valve assembly that I have ever seen requires a separate tank line when using the power beyond to operate other functions.

So how can I have both a tank port and a power beyond port if this adapter screws into the tank port on the valve?

 

[ericm979]

Often there is a PB adaptor that changes the flow in the valve so the PB port that is currently blocked off with a blank can be used.

Look up the make and model of the valve and find the documentation. It should tell you.

 

[3Ts]

Maybe this will help. It's from Surplus Centers "SV" series stack valves and has the most complete diagram I've seen.

 

[Tractor Seabee]

Key is every individual valve stack or module has to have an outlet to tank. It is all part of the internal passages in the valve bodies. Tank lines can be teed together if only one connection is available at the tank. Tank lines are low pressure as that is how fluid gets back to tank when a cylinder reverses. Most open center valves have a plug that has to be inserted to activate the PB outlet, and normally sold as an option. Surplus Center's technical desk is very helpful. Use them.

Ron