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Discussion Starter #1 (Edited)
And if I don't, feel free to call me an idiot. You won't be the first or last.

In a "normal" open center type configuration, you have oil coming from the pump and into a spool valve of some sort. When the valve is in the neutral position, a gallery is open between the pump in and tank out and fluid just flows through the valve unimpeded. If the spool is activated, flow is directed to the device controlled by that spool and blocked from the return passage.

Q1 - is this correct?

A power beyond kit seems to create additional pump in and tank out ports on the valve. With nothing connected beyond the valve, these ports would be capped shut and the valve operates as described above.

Q2 - Is this correct?

If you install another valve "beyond" the aforementioned valve with PB, you plumb that valves pump in and tank out ports to the primary valve and the pass through gallery is blocked in the valve with the PB kit installed so that pass through now flows to the beyond valve and back.

Q3 - is this correct?

So if I wanted to add another function elsewhere (say a rear SCV to control the angle cylinders of a back blade) what would be the difference between simply "splicing" into the existing tank return line or installing a PB kit? I understand that the existing SCV would have priority in either case. I guess what I'm wondering is what does a PB kit bring to the table besides potentially easier plumbing?

Al
 

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And if I don't, feel free to call me an idiot. You won't be the first or last.

In a "normal" open center type configuration, you have oil coming from the pump and into a spool valve of some sort. When the valve is in the neutral position, a gallery is open between the pump in and tank out and fluid just flows through the valve unimpeded. If the spool is activated, flow is directed to the device controlled by that spool and blocked from the return passage.

Q1 - is this correct?
Correct

A power beyond kit seems to create additional pump in and tank out ports on the valve. With nothing connected beyond the valve, these ports would be capped shut and the valve operates as described above.

Q2 - Is this correct?
Not quite. With Power Beyond there is no valve. Just a pressure-out and return hose connection on the tractor. Any valving or flow control is normally provided by whatever device/implement you plumb in to the hoses.

If you install another valve "beyond" the aforementioned valve with PB, you plumb that valves pump in and tank out ports to the primary valve and the pass through gallery is blocked in the valve with the PB kit installed so that pass through now flows to the beyond valve and back.

Q3 - is this correct?

So if I wanted to add another function elsewhere (say a rear SCV to control the angle cylinders of a back blade) what would be the difference between simply "splicing" into the existing tank return line or installing a PB kit? I understand that the existing SCV would have priority in either case. I guess what I'm wondering is what does a PB kit bring to the table besides potentially easier plumbing?
I don't think that is correct but I will let someone with more know chime in. Again, there are no valves with PB. Just full wide-open flow from the tractor.
 

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Remember that power beyond valves have two outlets, the PB, and the tank return.

all valves will have two outlets, except the last valve, which only has one outlet.

If you disconnect a downstream valve, the power beyond port CAN NOT be blocked,
it must return to the tank.
 

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I think I understand your confusion and will hopefully square you away with a couple quick distinctions of the implementation of "Power Beyond."

First, there's the general configuration of an open center hydraulic system: You seem to have this down, but it's mucking up your perception of the second part (I'll get to in the next paragraph). With an open center system, the valve has a tank port and a power beyond port to relieve fluid from the spool(s). When you engage a spool, the open center is moved to apply fluid (and thus pressure) to the work port on one side while the other port is diverted to the "tank" or drain port so fluid in the opposite side of the cylinder can escape without pressure. Valves down-stream of this valve now have less (if only partially engaged) or no (if fully engaged) fluid available to them as the inlet fluid is being directed to the selected work port. This is why you can't use your 3pt hitch and your loader at the same time. The 3 point hitch is the last valve in the circuit on most (if not all) tractors. When there are no spools engaged, fluid passes through the center(s) of the valves all the way back to the tank through the power beyond ports on any valves in the circuit.

When you add a "Power Beyond" port to the system, this is actually an external loop of the power beyond port(s) of the other valves. Any equipment you connect to this circuit will see the return valve as the tank drain (even though it's actually being sent back into the power beyond circuit), and that completes the fluid's path to the tank. You could make it work with an additional tank drain connection, and then have full external use of the additional valve spools and 3pt hitch, or you could get a valve capable of handling the higher pressure on it's tank drain port but those are usually more money. Another option if you were needing to use the 3pt hitch while the power beyond circuit was connected to an implement (like a log splitter) would be to put a check valve in the tank drain and then "T" the PB and T connections before returning them to the tractor. That way when the 3pt hitch is pressurized, there would be no pressure applied to the tank port on the equipment, but it would work normally otherwise.

Is that helpful?
 

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Sorry if this is a hijack of the thread.

If you want to use a sub-plate and valve,
is an open center sub-plate the correct part to select?

I have found what is called an open center sub-plate for
an electric valve. And the diagram shows in input P and output T
that looks like it is alway open to allow flow of the PBeyond.
And and A opening and B opening for the valve.

Is this correct?


If Yes then:
It's a little hard to understand how any work will get done
when you open a valve on the sub-plate. It seems like the flow will
always go back to the T, tank.

But, pressure in a contained area is everywhere the same.
So, to move the cylinder, it will move if it takes less than system
pressure, to move the load?

I hope this is correct, otherwise I feel stupid.
 

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Sorry if this is a hijack of the thread.

If you want to use a sub-plate and valve,
is an open center sub-plate the correct part to select?

I have found what is called an open center sub-plate for
an electric valve. And the diagram shows in input P and output T
that looks like it is alway open to allow flow of the PBeyond.
And and A opening and B opening for the valve.

Is this correct?


If Yes then:
It's a little hard to understand how any work will get done
when you open a valve on the sub-plate. It seems like the flow will
always go back to the T, tank.

But, pressure in a contained area is everywhere the same.
So, to move the cylinder, it will move if it takes less than system
pressure, to move the load?

I hope this is correct, otherwise I feel stupid.
Are you looking at something like this? https://www.surpluscenter.com/_MoreSpecs/DR9-5883-2.pdf

This sub plate would not work with a valve in use and something else down-stream of it also trying to use pressure.
 

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Are you looking at something like this? https://www.surpluscenter.com/_MoreSpecs/DR9-5883-2.pdf

This sub plate would not work with a valve in use and something else down-stream of it also trying to use pressure.

I'm not really asking this question.

But, using this diagram in your pdf, if you hooked up P and T to the Power Beyond,
would the valves connected to A and B work
or move a cylinder?

Would this be a proper use of the power beyond?
 

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I'm not really asking this question.

But, using this diagram in your pdf, if you hooked up P and T to the Power Beyond,
would the valves connected to A and B work
or move a cylinder?

Would this be a proper use of the power beyond?
It would work, but you'd need to make sure not to use the connected valves at the same time as the 3pt hitch.

That valve block represents how the 3pt hitch integrates into the tractor's system. There is nothing but the tank beyond it, so there is no power beyond port on it's valve body.
 

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And if I don't, feel free to call me an idiot. You won't be the first or last.

In a "normal" open center type configuration, you have oil coming from the pump and into a spool valve of some sort. When the valve is in the neutral position, a gallery is open between the pump in and tank out and fluid just flows through the valve unimpeded. If the spool is activated, flow is directed to the device controlled by that spool and blocked from the return passage.

Q1 - is this correct? Sort of! When the spool is moved on an open center valve, the flow into the valve is directed to a work port and the other work port (now is a return port) is connected to the tank port in the valve.

A power beyond kit seems to create additional pump in and tank out ports on the valve. With nothing connected beyond the valve, these ports would be capped shut and the valve operates as described above.

Q2 - Is this correct? Power beyond does not change the pressure in port. When a valve is set up for power beyond, there is now a power beyond outlet port and a tank port. When the valve spool is centered, the oil flows in the "P" pressure port and out the "PB" port. No flow flows out the tank port when the spool is centered. When a valve is set up for PB, the PB port cannot be blocked. When the valve spool is moved off center, the flow in "P" is directed to a work port and the flow out of the PB port is reduced relative to how far the control is pushed. The other work port is connected to the tank port. This will return the oil from the function cylinder or motor to tank.

If you install another valve "beyond" the aforementioned valve with PB, you plumb that valves pump in and tank out ports to the primary valve and the pass through gallery is blocked in the valve with the PB kit installed so that pass through now flows to the beyond valve and back.

Q3 - is this correct? OK. The valve that is connected downstream of the first valve with PB, is connected so that the "P" port of the second valve is connected to the "PB" port of the first valve. The tank port of the second valve is connected to tank (the tank port on most all valves is restricted to no more than about 500 PSI of pressure) and the work ports are connected to the attachment cylinders. If you have another valve downstream like the 3 point rockshaft cylinder, then your second valve is actually in between the first valve and the rockshaft valve. In this case, the second (middle) valve has to also be set up with a "PB" also. In this case, you would connect the "PB" port of the second valve to the pressure port on the rockshaft valve. Then you would have to connect the tank port of the second valve to tank (no pressure) and the work ports would go to your accessories.

So if I wanted to add another function elsewhere (say a rear SCV to control the angle cylinders of a back blade) what would be the difference between simply "splicing" into the existing tank return line or installing a PB kit? I understand that the existing SCV would have priority in either case. I guess what I'm wondering is what does a PB kit bring to the table besides potentially easier plumbing? I'm not really following your thinking here. The main SCV is already set up with "PB". This line supplies the oil to the "P" port of the 3 point rockshaft cylinder. So, if you are going to add a rear SCV, you would have to remove the line that runs from the "PB" port of the main SCV and the "P" port of the rockshaft valve. Then you will have to connect a line/hose to the "PB" port of the main SCV and connect the other end to the "P" port of the rear SCV, which is set up with PB. Then connect a line/hose to the "PB" port on the rear SCV and connect the other end to the "P" port of the rockshaft valve. Then here is where the hard part comes in. You have to connect the "T" port of the rear SCV to a tank port on the tractor. There is really no need to install the JD PB kit if you are only going to install a rear SCV and no BH. You can do the same thing by connecting the hoses as I said above. If you use hose, use 1/4" ID SAE 100R17 hose. This hose is extremely flexible.

Al
Here is how I installed the rear SCV on my 1025R. You will see, I installed a "T" adapter in the existing tank line so that I could connect the "T" port of the rear SCV to the tee. http://www.greentractortalk.com/forums/fit-rite-hydraulics/114898-fit-rite-hydraulics-rear-selective-control-valve-installation-1025r-oem-power-beyond.html
 

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Discussion Starter #10
Thanks to all. Yes, that was helpful.

In rereading my post I can see that I didn't do a great job of explaining myself but you all seemed to get the point.

I actually have an engineering background, but it is electrical and not mechanical. Hydraulics are kind of like electronics, but not really. I wanted to make sure I understood the concept.

Conceptually it seems to me (to speak in electrical terms) putting an additional function in series with the tank return** from an existing valve accomplishes the same thing as PB. I also realize that the engineers that design this stuff actually do know more than I do. I'm just trying to understand the reason why you install a PB kit instead of "wiring them in series".

Thanks and regards,

Al

** This is kinda what I mean using no graphics:

Pump=======Pwr In [SCV] Tank out=======Pwr In [Another SCV] Tank out=========Tank
 

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Thanks to all. Yes, that was helpful.

In rereading my post I can see that I didn't do a great job of explaining myself but you all seemed to get the point.

I actually have an engineering background, but it is electrical and not mechanical. Hydraulics are kind of like electronics, but not really. I wanted to make sure I understood the concept.

Conceptually it seems to me (to speak in electrical terms) putting an additional function in series with the tank return** from an existing valve accomplishes the same thing as PB. I also realize that the engineers that design this stuff actually do know more than I do. I'm just trying to understand the reason why you install a PB kit instead of "wiring them in series".

Thanks and regards,

Al

** This is kinda what I mean using no graphics:

Pump=======Pwr In [SCV] Tank out=======Pwr In [Another SCV] Tank out=========Tank



PSI and volume.
 

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Thanks to all. Yes, that was helpful.

In rereading my post I can see that I didn't do a great job of explaining myself but you all seemed to get the point.

I actually have an engineering background, but it is electrical and not mechanical. Hydraulics are kind of like electronics, but not really. I wanted to make sure I understood the concept.

Conceptually it seems to me (to speak in electrical terms) putting an additional function in series with the tank return** from an existing valve accomplishes the same thing as PB. I also realize that the engineers that design this stuff actually do know more than I do. I'm just trying to understand the reason why you install a PB kit instead of "wiring them in series".

Thanks and regards,

Al

** This is kinda what I mean using no graphics:

Pump=======Pwr In [SCV] Tank out=======Pwr In [Another SCV] Tank out=========Tank
Yes and no. The tank out on a PB circuit is like a switched power wire. When you activate the valve, you shut off the flow to the circuit beyond that point and everything flows through the valve (unless partially opened, and then you're still limited by the ampacity of the circuit). The Tank would be your ground. You need to pass the power through other relays, but if one is closed up-stream, it opens the circuit downstream from it. The very last load (valve) doesn't need a relay as it's tied directly to ground.
 

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Thanks to all. Yes, that was helpful.

In rereading my post I can see that I didn't do a great job of explaining myself but you all seemed to get the point.

I actually have an engineering background, but it is electrical and not mechanical. Hydraulics are kind of like electronics, but not really. I wanted to make sure I understood the concept.

Conceptually it seems to me (to speak in electrical terms) putting an additional function in series with the tank return** from an existing valve accomplishes the same thing as PB. I also realize that the engineers that design this stuff actually do know more than I do. I'm just trying to understand the reason why you install a PB kit instead of "wiring them in series".

Thanks and regards,

Al

** This is kinda what I mean using no graphics:

Pump=======Pwr In [SCV] Tank out=======Pwr In [Another SCV] Tank out=========Tank
Just to be clear, PB is not putting another valve in series with the tank port. The tank port on a valve cannot be pressurized.
 

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Thanks to all. Yes, that was helpful.

In rereading my post I can see that I didn't do a great job of explaining myself but you all seemed to get the point.

I actually have an engineering background, but it is electrical and not mechanical. Hydraulics are kind of like electronics, but not really. I wanted to make sure I understood the concept.

Conceptually it seems to me (to speak in electrical terms) putting an additional function in series with the tank return** from an existing valve accomplishes the same thing as PB. I also realize that the engineers that design this stuff actually do know more than I do. I'm just trying to understand the reason why you install a PB kit instead of "wiring them in series".

Thanks and regards,

Al

** This is kinda what I mean using no graphics:

Pump=======Pwr In [SCV] Tank out=======Pwr In [Another SCV] Tank out=========Tank
I had you pegged as having extensive electrical knowledge by reading your responses. You definitely have been an asset to this forum. :hi:
 

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Just to be clear, PB is not putting another valve in series with the tank port. The tank port on a valve cannot be pressurized.
Maybe to add to the confusion or confirm my thoughts.

I thought that some hydraulic control valves that are not PB can be "converted" to PB with a add-on kit. So a valve that is not PB has an "IN" and an "OUT/TANK" (that usually cannot be pressurized).

Converting it to a PB valve or buying a valve already PB capable, there are 3 ports in addition to the cylinder ports: "IN", "PB" (which can be pressurized and connects to the next valve down stream) and an "OUT/TANK". The hydraulic flow when valve is not actuated (attached cylinder is not activated) is IN and PB are connected allowing an open center flow. When the cylinder is activated in either direction, flow from the IN-PB path is diverted toward the cylinder and cylinder exhaust flows into the out/drain to tank. When the valve actuates the cylinder, flow out the PB port is lessened because it is diverted toward the cylinder.

Let me know if I am on the right track.

Just my 2 cents.
 

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Discussion Starter #16
In response to Ray and Tom:

Let's see if I have this straight, and let's forget anything downstream for the moment. A regular old SCV will have a power in port and a tank out port. Assuming all spools are in neutral, a gallery inside the valve will be open between power in and tank out, allowing continuous flow through the valve when noting is active.

An SCV with PB will have *two* additional ports that I will call power out and tank in *AND* will block the internal pass through gallery. When the SCV is in neutral, fluid will flow out the "power out" port to a downstream device that should direct flow from its neutral position back to the "tank in" port.

To disable the PB functionality I would have to either loop the power out back to the tank in port, or plug both of those ports and reopen the internal neutral gallery.

Is that more-or-less correct?

Al
 

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In response to Ray and Tom:

Let's see if I have this straight, and let's forget anything downstream for the moment. A regular old SCV will have a power in port and a tank out port. Assuming all spools are in neutral, a gallery inside the valve will be open between power in and tank out, allowing continuous flow through the valve when noting is active.

An SCV with PB will have *two* additional ports that I will call power out and tank in *AND* will block the internal pass through gallery. When the SCV is in neutral, fluid will flow out the "power out" port to a downstream device that should direct flow from its neutral position back to the "tank in" port.

To disable the PB functionality I would have to either loop the power out back to the tank in port, or plug both of those ports and reopen the internal neutral gallery.

Is that more-or-less correct?

Al
Here's where you're crossing wires.

A SCV is a Selective Control Valve, a Power Beyond Port is just that - a port which connects another valve into the open center power beyond flow of the upstream SCV and the rockshaft valve/tank. Adding an external power beyond port doesn't do anything to any valves.
 

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Discussion Starter #18 (Edited)
Here's where you're crossing wires.

A SCV is a Selective Control Valve, a Power Beyond Port is just that - a port which connects another valve into the open center power beyond flow of the upstream SCV and the rockshaft valve/tank. Adding an external power beyond port doesn't do anything to any valves.
OK, I'm getting impression that I pretty much understand what it does but do not have a clue how - pretty much the opposite of my mindset before I started this.

I understand there are plain old SCV's (and for the sake of discussion my universe consists only of open center systems) that have a power in, tank out, and ports to control devices. Call this a Type I valve.

I think I understand there are SCVs with an extra two ports - one each for power and tank for downstream controls, These are PB ports. Call this valve a Type II

So what exactly does a PB kit do? I had the impression from browsing maybe too many mobile hydraulic websites that it converted Type I valves to Type II valves. If it does not, where does it connect and how does it work?

BEFORE YOU REPLY SEE MY FOLLOWUP POST BELOW.

Your pal and mine,

Al
 

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Discussion Starter #19 (Edited)
Take a look at this.

This is for a 1 series and if I'm looking at it correctly, I'll be damned if the power beyond kit does not function exactly like I suggested with my "wiring in series" comment.

The tank return hose from the SCV to rockshaft is removed from the tank out port of the SCV and routed to the back of the tractor. The tank out port from the SCV is plumbed via a new pipe to the back of the tractor. Since no backhoe or anything else is attached, the PB port on the back is plumbed via a hose to the tank return port (looped).

So I guess I need to forget everything I thought I learned from various mobile hydraulic websites and understand that a PB kit for JD is "simply" a self contained plumbing kit that does in an elegant engineered fashion what I might be tempted to do with DIY parts from TSC.

Feel free to throw virtual rotten eggs or insult my continuing ignorance.

Al
 

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Take a look at this.

This is for a 1 series and if I'm looking at it correctly,
I'll be damned if the power beyond kit does not function exactly like I suggested with my "wiring in series" comment.

Feel free to throw virtual rotten eggs or insult my continuing ignorance.

Al
If two valves are "wired in series" without the extra return port(s), then there is a relief valve between the pump and the first valve.
 
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