What does power-beyond really mean?

[MJPetersen]

If I want to add more hydraulics, and my valve for my FEL does not have a PB port, I could get a new valve with a PB port and go through the new one first and run my FEL valve off the PB port of the new valve?

What you suggest will work. I would ask, "where does the 3pt get its hyd from? Is it from the out flow of the FEL? Maybe it would be easier to add PB to your FEL valve. For those valves that are setup for it the PB kit involves little more than a headless plug. to divert the flow.

Mike

 

[JerryG]

One dealer would make up six sections of hose and some fitting and include a $170 single spool valve for $350 total. That is pretty expensive to my thinking. When I asked how to hook it up I was told that "I would be able to tell when I saw the hoses and could the figure it out." I asked for a simple sketch and they told me that they would have to add a half hour labor to the order to produce an engeering drawing and send it along with the order. I suspect they are thinking that I'm trying to get free advice or they just don't know either. Any help from you experts is welcome. Please don't suggest to go back to the grapple supplier, I already did that with a lot of "each tractor is different" no help answer. Thanks again

Most remotes run a lot more than $350, even when someone does all the work themselves. You can check with the Surplus Center for a valve. They usually have better prices that most tractor dealers. Since you haven't filled out your profile, we can't tell what size tractor you have to make suggestions on specific valves.

Sometimes a simple drawing is by far the easiest way to get something straight. Here is a drawing of the way the valves were installed on my last two tractors. I've changed the things which were model specific to the tractor I have. I hope that it helps.
Control Valves

BTW
Welcome to TBN.

 

[dvan1966]

What you suggest will work. I would ask, "where does the 3pt get its hyd from? Is it from the out flow of the FEL? Maybe it would be easier to add PB to your FEL valve. For those valves that are setup for it the PB kit involves little more than a headless plug. to divert the flow.

Mike

The 3pt gets its hyd before the FEL. I bought the tractor used with FEL but from looking at the paperwork a previous owner had the FEL added. The 3pt and power steering are off the hyd. block on the side of the tractor and I haven't had the side panel off yet to get a better look at it. Also my valve has 6 hoses coming from it, 1 in, 1 out, and 4 going to the loader. I can't see any markings on the valve that says another out or beyond.

 

[jgrreed]

Most remotes run a lot more than $350, even when someone does all the work themselves. You can check with the Surplus Center for a valve. They usually have better prices that most tractor dealers. Since you haven't filled out your profile, we can't tell what size tractor you have to make suggestions on specific valves.

Sometimes a simple drawing is by far the easiest way to get something straight. Here is a drawing of the way the valves were installed on my last two tractors. I've changed the things which were model specific to the tractor I have. I hope that it helps.
Control Valves

BTW
Welcome to TBN.

Hi Jerry,

Can you, or someone else explain to me something from the drawing that is linked above?? Do the green 'sump' lines and the red 'return' lines both end up back at your reservoir??

Thanks,

-Jer.

 

[aczlan]

Can you, or someone else explain to me something from the drawing that is linked above?? Do the green 'sump' lines and the red 'return' lines both end up back at your reservoir??

yes they do, however the red line is a "pressurized return" whereas the green line is a "free flow return" ie: you could cut into the red line and put in another valve, without any problem. but the green line is to return the "spent (de-pressurized)" fluid to the tank, and it has to allow free flow to the tank.

Clear as mud?

Aaron Z

 

[jgrreed]

yes they do, however the red line is a "pressurized return" whereas the green line is a "free flow return" ie: you could cut into the red line and put in another valve, without any problem. but the green line is to return the "spent (de-pressurized)" fluid to the tank, and it has to allow free flow to the tank.

Clear as mud?

Aaron Z

If you were to join the two flows, would you have to use a one-way valve to prevent the high pressure PB return flow from entering, and damaging, the sump line??

If you can join the two flows, should/can you put a filter on a high pressure PB return circuit?? Should they both be filtered prior to returning to the tank, or is the unused PB circuit still clean from it's last trip through??

The if PB fluid makes it back to the reservoir in the PB return line, it should not have seen any cylinders or motors along it's path, yes/no??

-Jer.

 

[aczlan]

If you were to join the two flows, would you have to use a one-way valve to prevent the high pressure PB return flow from entering, and damaging, the sump line??

IIRC (and this is just a guess) you shouldn't join them UNLESS they are the last line in the system, then the joined line should be large enough that it can handle both flows without creating any backpressure

If you can join the two flows, should/can you put a filter on a high pressure PB return circuit?? Should they both be filtered prior to returning to the tank, or is the unused PB circuit still clean from it's last trip through??

You can filter the PB return, the should part I will leave to someone who knows more about hydraulics than me.

The if PB fluid makes it back to the reservoir in the PB return line, it should not have seen any cylinders or motors along it's path, yes/no?

That is correct, it will have passed through the valves but not through any thing else (cylinders, motors, etc).

Aaron Z

 

[Spaceman]

Yes, you can hook up valves in series without power beyond, but for the reasons given in the link, it is better to use a power beyond sleeve and return to sump for each valve.

Do you tee in to the same point for the sump? Don't all of the valves except the last one in the series have to be closed center?

 

[kennyd]

Do you tee in to the same point for the sump? Don't all of the valves except the last one in the series have to be closed center?

You can only Tee the low pressure return lines, and all the valves MUST be OPEN CENTER, not closed center!

 

[kruss77]

More 'basic' questions:

1. I gather that the PB is simply a bypass that routes pressurized fluid past an in-series spool so that other downstream spools aren't disabled when an upstream spool is in use (ie: no longer in center open position). True/False?
2. Why can't the center-open spool circuit be used for the PB function? Is it because actuation of an upstream spool cuts all fluid flow to subsequent spools in the series when the center open valve is closed (thereby rendering all downstream spools useless)? Yes/No?
3. In a system of PB spools, even though fluid is bypassing the first spool, doesn't the use of the first spool in the system cause a pressure drop in the PB line -thereby affecting the performance of all subsequent spools in the series? In other words, isn't it unlikely that any downstream spools will function properly while an upstream spool is in use due to a pressure drop caused by the in-use upstream spool? Yes/No? Why?
4. If yes, what is the alternative to allow multiple spools to be used simultaneously?
5. Also, why does the last spool in the chain not need to be PB? Doesn't the pressurized fluid need a bypass back to the reservoir, or is that accomplished by the low pressure return circuit?
6. When a spool is used to actuate a cylinder and the fluid in the non-pressure side of the cylinder is forced back out, what prevents the fluid from the non-pressure side of the cylinder from rushing out of the cylinder and into the low pressure return? Is there some sort of flow restrictor in the spool body itself that prevents this?
7. How would a hydraulic motor be integrated into a closed circuit system like this where the hydraulic motor would be on for prolonged periods of time even though other spools would also need to be used (say, for running a blower motor for a lawn vac)?