Power Beyond Port?

[kwolfe]

What is power beyond. When installing my loader, I saw the input, output and "power beyond" ports that I plumbed. I can understand what the first two do, but I am not quick sure what the 3rd is for. Any information would be approciated.

By the way, this is my first experience with hydraulics, so try and keep the words small.

 

[MadReferee]

Input (or inlet) = pressure in from the pump

Output (or tank port) = return to tank/sump port for neutral pressure fluid exhausted from the cylinders

Power Beyond = pressure out to the next valve in the series circuit

The actual workings have been expained many times here. Do a search for more information.

 

[kwolfe]

I read some of your posts from a while back, now I have a better understanding, however how does it operate in my little bx1500 loader with 3 cyclinders? Does it power the bucket cyclinder?

 

[MadReferee]

I read some of your posts from a while back, now I have a better understanding, however how does it operate in my little bx1500 loader with 3 cyclinders? Does it power the bucket cyclinder?

Power beyond has absolutely nothing to do with your bucket cylinder or cylinders. A valve with power beyond does not exhaust neutral pressure fluid from the work ports back into the pressure stream, rather it exhausts fluid thru the tank port. The power beyond port always has pressure fluid.

Your BX loader valve has 2 spools, one controls any and all bucket lift/lower cylinders and one spool controls any and all curl/dump cylinders. The ports on the valve that connect to the cylinders are called work port and each spool has two. At any one time one work port is pressure to the cylinders and the other is exhaust from the cylinders.

 

[RalphVa]

Power beyond is normally a port (and usually a separate joy stick for controlling it) for running something like a log splitter off the back end or maybe a thumb on the FEL on the front. Not sure the BX1500 has that option kit. You'll have to ask your dealer, or maybe someone here knows.

Ralph

 

[rbargeron]

Power Beyond is a feature that a hydraulic control valve may have - or may not have. It is only a valve feature. It stops there. I think the confusion that exists around Power Beyond is that other stuff is often sold along with it - and the impression is left that the added stuff is part of Power Beyond. But power beyond is just a feature of a valve. A control valve with power beyond has a center section that other downstream valves can be connected to. Those other downstream valves may or may not be on the tractor. For instance, on a machine with a backhoe attachment, the FEL control valve may have a power beyond outlet but it isn't connected to any downstream valves until the backhoe is attached - then the pb hose supplies the backhoe valves. Many other machines are sold with extra hydraulic connections AND a control valve for them fed from a power beyond port.

 

[MadReferee]

Simply put, power beyond refers to the configuration of the spool valve's outlet section. Nothing more, nothing less. People have used it to refer to other things but it is simply just the configuration of a valve's outlet section ports.

When the outlet section of a valve is configured for power beyond, the work port exhaust fulid is isolated from the normal flow fluid output, making 2 outlet ports. One outlet port is the exhaust or return to tank port that carries neutral pressure fluid from the cylinders back to the tank. The other port is the power beyond port that allows the fluid flow to power valves beyond this valve.

When the valve spools are in neutral, fluid flows thru the valve and exits at the power beyond port. When a spool is activated, neutral pressure fluid from the cylinders is sent to the tank port instead of being dumped back into the main flow.

 

[kwolfe]

I think I understand now. My bx does have the port. I did all the plumbing for the loader (great learning experience). I have three plumb lines that come out of the aux hydro block (in, out, and PB). All three lines plug into the loader control valve. That is why I ask. The loader control valve must simply loop the PB back into the system. Is this a fair assumption?

Sorry if my terminology is a little off.

So if I wanted to hook a hudro top link up, I would need to run the PB line into a valve control (with lever) and would have to tap into the existing exhaust port, yes?

 

[MadReferee]

The loader control valve must simply loop the PB back into the system. Is this a fair assumption?

All valves are connected in series (an inlet to an outlet). The PB port is the outlet exit from the valve that continues this series circuit.

So if I wanted to hook a hudro top link up, I would need to run the PB line into a valve control (with lever) and would have to tap into the existing exhaust port, yes?

Sort of. The PB port from a previous valve connects to the inlet of your new aux valve. The PB from the new aux valve connects back into the series circuit. The tank port from you aux valve can be teed with any other tank line since this goes directly to the tank/sump and is not the main flow. It is the ONLY line that can be teed as it is not directly a part of the main flow series circuit.

 

[kwolfe]

OK, now moving back to confused. Let me try this. When I installed the loader, I ran three lines (in, out, PB) from the hydro block (above left rear tire) under the tractor and into the gismo (tech term) that the loader control joystick comes out of. All three lines go into this thing. In that joystick gism there are 3 valves (correct?). These control the flow of hydro fluid depending on how I move the stick. There are four lines that come from the gismo that go to the loader. I am assuming that two (in & out) for each arm cylinder. What about the dump cylinder (only one)?

Sorry I am so slow, however I just don't speak hydroneese.

Also, really appreciate the help. I am taking notes.

 

[MadReferee]

OK, now moving back to confused. Let me try this. When I installed the loader, I ran three lines (in, out, PB) from the hydro block (above left rear tire) under the tractor and into the gismo (tech term) that the loader control joystick comes out of. All three lines go into this thing. In that joystick gism there are 3 valves (correct?). These control the flow of hydro fluid depending on how I move the stick. There are four lines that come from the gismo that go to the loader. I am assuming that two (in & out) for each arm cylinder. What about the dump cylinder (only one)?

What you are calling a gismo is in fact the loader spool valve.

Your loader valve has 2 spools, in other words it has 2 functions. One spool controls the raise/lower cylinders and the other spool controls the bucket curl/dump cylinders. If there are 2 cylinders for that spool function, which most tractors have, then those 2 cylinders will be connected in parallel. The cylinders connected to one spool are independent of the cylinders connected to the other spool.

Each spool has 2 work ports These work ports connect to the cylinders for that function. Depending on the direction of the lever, one work port will be applying pressure to the cylinders and the other work port will be exhausting fluid from the cylinders.

The loader valve itself has 3 ports, inlet, outlet (aka return to tank), and power beyond. The loader valve is connected in series with the hydraulic pump, 3pt and tank. The series circuit flow enters the valve at the inlet and exits via the power beyond port. The return to tank port is used for exhaust fluid from the work ports.

 

[kwolfe]

Mad,
Thanks a lot. That is what I needed to hear. The PB port is actually and outlet (so to say). Now I see that if I were to connect a hydro top link, I would have to be teed into both the inlet and PB.

The pictures on this link helped me out, although I don't know if they accurately depict my scenario. It appears from the drawings that the only difference is that my loader would be using the PB port as on outlet as approsed to sharing the fluid exhaust outlet from the work cylinders.

Technical help

 

[MadReferee]

The PB port is actually and outlet (so to say). Now I see that if I were to connect a hydro top link, I would have to be teed into both the inlet and PB.

The PB port is the main flow outlet and it goes to the next valve in line (usually the 3pt).

You cannot TEE into either the inlet or power beyond ports. All valves must be in series. This means you must break the line and insert your valve. However, you can tee into any return to tank line.

The link you posted has good pictures and I have referred people to it many times. Your tractor is the picture that is titled Open Center Circuit with Power Beyond.

 

[kwolfe]

Got it now. Thanks a lot for the information.

 

[tenderman]

So if I understand correctly, the 'outlet' port dumps to the tank and the 'power beyond' port is used for series connecting valves in an open center system. For yearas I have been using the inexpensive Prince four-way valve and just connecting the outlet of one to the inlet of the next, ad nauseum. The systems have been working correctly, and I'm not even sure if there is a 'power beyond' port on these particular valves. I assume a device plumbed out of the regular 'outlet' port would still function, but is there a difference in the way the flow is handled with 'power beyond"?

 

[jinman]

I believe your valve should have a "P" tap for pressure, "T" tap for tank, and a "PB" tap for power beyond. The outlets to the working cylinders are separate from these. The "P" tap of the first valve should be connected to the pump pressure. All the "T" taps can be tied together in parallel. The "PB" tab of the first valve then attaches to the next valve's "P" tap and this process continues to the last valve where the PB tap is tied back into the system or into the "T" line if it is the last valve in the open center system.

The only time the PB port has full pressure is when the particular valve is centered. The T ports serve to vacate the fluid from the non-pressure side of the working cylinder via the spool in the working valve.

I'm sure someone will correct me if I've stated this wrong, but I believe my description is the proper way to connect the valves.

 

[tenderman]

Thanks for the response. I don't recall seeing those labels. The tractor has two quick disconnects on hoses coming off the main valve. I tested the hoses and they each have pressure;one when the hydraulic control lever is pushed in one direction, the other when it is pushed the other way. That leads me to believe that the main control valve on the MM is basically a four-way valve. I figured I would hook my loader valve up and plan on only using the lever in one direction and it should function as an open center system. My question is more what port do I hook pressure to when I add a second, third, etc... valve for other things. Also I am curious how Power Beyond differs from a standard outlet on a regular four-way valve.

 

[jinman]

Thanks for the response. I don't recall seeing those labels. The tractor has two quick disconnects on hoses coming off the main valve. I tested the hoses and they each have pressure;one when the hydraulic control lever is pushed in one direction, the other when it is pushed the other way.

That's the way remote hydraulic taps work. The lever reverses flow so that you could hook those lines to a Double-acting hydraulic cylinder and power it in both directions. When you want to use the remote to power another open center valve, you move it to one position or the other and leave it while you are using your open center control valve. Many of us hook up log splitters that way.

The 4-way valve you are talking about is just a two-spool self-centering valve isn't it? Like a joystick valve?

 

[J_J]

On your valve, you may also see I for IN port, T for TANK port, PB for POWER BEYOND. A or B for work ports. A1 B1, A2 B2, etc.

Non PB valves are usually designed for one valve operation and the OUT/T fluid goes to tank.

Tractors without PB ports also use the T port to connect to the 3pt port, and then to tank. 3pt valves always has a relief valve, for basic operation. Pump to 3pt to tank.

If your valve has PB port, it is best to use it. Valves in a open center system, are connected in series. The first valve upstream has priority.

There is also a back pressure limit on the tank port. Most all tank ports should go to tank.
Most times you will only see fluid coming out the T port, is when the cyl is extending or retracting.

The last valve in an open center hyd circuit is usually the 3pt valve.