Another remote valve thread..

[tatra805]

Kennyd,

Hard to explain, i would say as an example a log splitter with own control valve (OC).

or say i have a transport belt driven by a hydraulic engine without speed control just on/off. Then i need a on/off valve on the tractor.

Add to this speed control, then i would need a settable flow regulating valve on the tractor.

I see a lot of devices with hydr engines that have no valves just the 2 hose for direct plug in and no need for speed control.

If i need to attach something non continues as hydr cylinders, say the up-down left-right moving things i can use the output i use for the cylinders of the dumptrailer.

So i saw these bottom RS connections as a continues high power output. I did get the safety point that it would be better to be able to switch this exit and i added the settable flow control as a speed regulation....

 

[kennyd]

For a logsplitter or another device with it's on valve you would put it in series with the PB line at the bottom before it gets back to the 3PH.

-You cannot Tee into high pressure lines...
-All valves must be in series...

You setup would look like this in the attachment...Where the RS couplers at the bottom are joined together unless you added in something else.

Sorry for messing up your beautiful drawing!

 

[tatra805]

Thats what drawings are for!

Now, it all started to make sense till I called my dealer at the other end of europe asking him how he is plumbing things..

I should first mention he knows PB ports and tractor hydraulics quite well but sticks to this simple setup as he had too many customers running into problems with complex plumbing.

He says to plug in as in the drawing, meaning a series of valves but no use of PB ports.. now i get confused again...

The restriction would be that you can only operate 1 spool at the same moment. Not a big issue to me if i think about it. 1 drawback would be that the hydr. motor would stop when moving the fel or something else.

objections?

 

[Eric_Phillips]

Thats what drawings are for!

Now, it all started to make sense till I called my dealer at the other end of europe asking him how he is plumbing things..

I should first mention he knows PB ports and tractor hydraulics quite well but sticks to this simple setup as he had too many customers running into problems with complex plumbing.

He says to plug in as in the drawing, meaning a series of valves but no use of PB ports.. now i get confused again...

The restriction would be that you can only operate 1 spool at the same moment. Not a big issue to me if i think about it. 1 drawback would be that the hydr. motor would stop when moving the fel or something else.

objections?

Here is the remedial hydraulic question. If you can plumb it this way what is the use of PB? What is the difference between the return line with out power beyond and the the PB when installed?

 

[kennyd]

Thats what drawings are for!

Now, it all started to make sense till I called my dealer at the other end of europe asking him how he is plumbing things..

I should first mention he knows PB ports and tractor hydraulics quite well but sticks to this simple setup as he had too many customers running into problems with complex plumbing.

He says to plug in as in the drawing, meaning a series of valves but no use of PB ports.. now i get confused again...

The restriction would be that you can only operate 1 spool at the same moment. Not a big issue to me if i think about it. 1 drawback would be that the hydr. motor would stop when moving the fel or something else.

objections?

I object. You really should use the PB, that is what it's for.
That way also can put very high pressure in the OUT port of the previous valve in the circuit-which most are not designed for.

 

[kennyd]

Here is the remedial hydraulic question. If you can plumb it this way what is the use of PB? What is the difference between the return line with out power beyond and the the PB when installed?

Not using the PB can put very high pressure in the OUT port of the previous valve in the series like a mentioned, and it also cut's the flow to downstream valves when one of operated. It is really a less than ideal setup.

 

[john_bud]

Thanks for the input, trying to follow...

John bud you write: "The PB port has 100% full flow going thru it (except when the flow is diverted by the valve actuation, used then sent to the "return" port)."

Is it my misconception that the PB port differs from the return port by the fact that it diverts the high pressure flow side and thus not interrupts the supply of all valves that are connected to it?

Otherwise its function would not differ from the return line? As in an OC system the flow continues goes from IN to OUT and is only interrupted when a spool is opened and requires flow while shutting off the return line?


KennyD,

but i dont see how the RS would get any pressure as long as the 3pt is OC flowing.

So this one is better?

The drawing that is remaining is the "correct" way to do it with one exception. The box "FEL" is not doing anything and does not need to be there as the box "2 spool valve" is performing that function.

Couple "clear ups".

The "out" also called "return" ports on hydraulics is for what I call used fluid. That is fluid that has had the high pressure used up. It will be at a low pressure, typically under 1-200 psi and often down around 50 psi. You can't use that flow to power stuff as it NEEDS to be a low pressure fluid. Some people may "cheat" like you showed and they may even get away with it for a while, but it will catch up to them with leaks and possible valve damage. When you use the valve to power something, ALL of the fluid from the pump is redirected. The "used" low pressure fluid is returned to the reservoir and NO FLUID goes out the PB to the next circuit downstream.

The PB or Power Beyond port is used to supply hydraulic power BEYOND or after the valve. It is built to contain the full pressure of the pump. If you put valves in order 1, 2, 3, etc and the next higher number is powered by the PB port. When #1 is used there is no flow to the valve #2, 3, etc. People sometimes will see this when the loader or 3pt is used at the same time and one of them doesn't work. In slightly different language, If you don't use the hydraulic power in device #1, you can direct it with the PB port and use it in device #2. If you don't use the hydraulic power in device #1 or #2, you can direct it with the PB port and use it in device #3. and on down the line.

It's hard to explain these concepts over a keyboard with no feedback, so sorry if you already know these things. Not trying to talk down, just trying to give enough examples that it is clear. Hope it helps a bit.

jb

 

[tatra805]

Thank you all for the feedback. It keeps amazing me how beneficial internet and sites as TBN can be.

John Bud: The FEL valve is the one on the tractor now operating the FEL and the 2 spool i want to add for other applications.

I was blowing the valve while operating things to find out the functioning a bit. (hydraulic oil has no taste..)

WHEN BLOWING A EXIT PORT OR THE PB I HAD SAME RESULTS


So i called the manufacterer of the 2 spool valve i bought. Long text but maybe interesting to some. Friendly patient man...

My valve has a PB port, 2x IN and 2x OUT.

His explanation was:

2x IN and 2x OUT : for mounting convenience one on top and one on the side of the valve block.

PB port: on simple valve designs such as standard spool valves (1-2-3-4-... spool) The internals of the block allow for a the PB to be nothing more than a extra OUT connection and function as such. The valveblock is made upto the task.

In more complex valve designs where most of the time the same base block is used the internals are made so that indeed a hole needs to be plugged with a PB plug (which blocks internally the flow to OUT) and the PB port gets a dedicated flow which is "separate" from the normal OUT exits.

To drive it home: They have x types of casts (the base blocks) which are machined to Y basic blocks.

These basic blocks are then further configured by the internal parts (separate parts building up the valves) and secondly extra machining eg drilling through an internal wall to make an extra oil passage as needed by a type of valve configuration.

In the case of pluggable PB this plug is closing one of these extra machined passages. In case of the standard spool valves this passage is not there and therefore does not need to be plugged.


On the remark of valve damage and leaks in case of a "wrong" out-to-in configuration he went but gave a nice simple clear explanation:

Imaginge the main oil stream as a TUBE.

All internals are made to cope with the pressure. The oilway from In to Out or In to PB is nothing more than a "tube" in the block which is also designed for these pressures. The only thing that could happen when pressurizing the complete tube with a plugged exit is the plug breaking.

In the old days a safety valve was a plate with breaking lines in cross form, so when overpressure happened the plug would break and let the oil flow out.

Now when connecting in series (out to in) what will happen? Your "tube" is just longer going from hose to valveblock to hose to valveblock to exit. If you operate the last valve in line the whole "tube" becomes pressurized. So what? If your hoses and connectors are right... nothing.

Same happens when making the "tube" from hose to In to PB to hose to IN to OUT.

PB ports are a result of something, not a cause. Everybody sees them as necessary and people are educated that way.
PB is the result of complex valves that need internal flow to be redirected internally and physically/mechanically design preventing to use the OUT port as exit.
If you have a simple valve design that does allow to use the OUT port why would you make it complex and make a dedicated (useless) PB design??

We have them on our simple valves because of universal machining in our production and... to avoid calls like this.



This might stirr the pot a bit but it also made sense...

 

[john_bud]

Well, you are getting more of an education than anticipated! Glad you are sharing the information with us. I for one only have "some" understanding, based on the valves I've played with being the type with the plugable PB port. The explanation given to you sounds plausible, and it's your $$ and tractor.

Keep us in the loop as you progress.


jb

 

[tatra805]

Had no internet connection for a couple of days so loooooots of time for plumbing hydraulics

Pics to follow when servers are back running completely.


So, i installed the hydraulics as in my last picture going from the explanation of the manufacturer regarding the PB ports.

Things work a charm.

The shop did not have a second valve block in for the rear-command so i looped it at the moment.

Tried out the front and backs and i do not seem to have a problem. Also, when operating the FEL i am still able to use the grapple control.

I would recommend everybody to install a pressure gauge immediately it just shows things so clearly.

What i found:

- System pressure 250Bar (! so good for a 15 year old tractor)

- FEL command stops flow at end of stroke while maintaining pressure in cylinders. The new valve block does not do this. Because the safety valve is set too high? I have no idea how this works.

- Idle pressure is between 50 and 75 Bar with the 3pt set at all positions but completely down or at the presettable down position (i have 2 3pt controls with 1 being a presettable low position). I suppose this is normal.

- Trailer is dumping full loads of dense, wet heavy manure. Pressure rises to 150 bar at start of dump to 100 bar at end of dump. Happy camper.

- I quickly fabbed a grapple and although it is working will need to reinforce it a bit as i greatly underestimated the forces of this small hydraulic cylinder.

Some advise to others:

- Measure your hoses precisely and then do it once again. Being on the long side is good but too long not. (ask me) A trick is to use a piece of rope to make your routing and then measure the lenght of rope.

- Install the hoses on the valveblock before putting it on the tractor. Tight spaces and long spanners are a pain.

- install a pressure gauge. if not then 2

- Do not tighten any connections (except the valve block) till all hoses are in place. It will avoid tension on the hoses and make routing them MUCH easier.

- Pressurize the system the first time on your lawn and not your driveway. Hydraulic oil is a pain to clean. Leave it sitting overnight and check for leaks in the morning (i had a leak showing only the second day, probably after all air was slowly purged)

- Check your oil level again after a couple of hours of operating.

- Keep being aware that you are working with Hydraulics, dont understimate the power of it. I would strongly advise to make your test run alone and with all things mounted as should be and sitting in the drivers seat.