Grapple Hookup

[kennyd]

Ive been reading this thread with great interest as I would like to swithch my grapple over to run off of a new valve like wvpolekat's to free up a set of rear remotes for a hydraulic top link. Ive been trying to learn some basic hydraulic stuff and thought I was doing ok until wvpolekat put up his schematic diagram. Now i'm confused.
I thought someone would say he would have trouble because he was feeding
his pto hydraulics with the out port of his valve instead of a PB port. That
confuses me. If you can do that why would you ever need a PB port. I can
see how his grapple will work as long as he doesnt touch his lift arm control.
But what would happen if he had a heavy weight on the lift arms and
inadvertantly operated the grapple valve while he was raising the lift arms??
Someone please explain - maybe I misunderstood something further back
in this thread.
Thanks.

The simple fact is that no subplate for a solenoid valve comes with a PB connection.

The "ideal" way is to use a PB equipped valve whenever possible-but it is not always feasible. Some here will say that your valve will blow-but cannot/will not answer why backhoes, logsplitters and solenoid valve are fine to hook up without PB connections.

 

[TTTTTT]

Heres a setup I did with a manual valve (no electrics). Meant for my snow plow angling, but ready and waiting for a grapple setup or anything else for the front end. I came off my loader valve into my new valve and then out from that valve to my rear remotes and 3pt. The valve is an open center to allow flow through when not in use. As JJ mentioned and being open center throughout when a valve is activated pressure builds to use it. It was basically located in line (serries) with everything else. Simply setup but has worked well as needed.

Link to the thread
http://www.tractorbynet.com/forums/hydraulics/154201-front-qd-mod-plow-hookup.html

A few detailed pics of new valve and plumbing.



I was originally going to to an electric soilenoid setup but decided for cost and simplicity to do it this way.

Hope this adds to the conversation

Dave

 

[wdchyd]

Th simple fact is that no subplate for a solenoid valve comes with a PB connection.

The "ideal" way is to use a PB equipped valve whenever possible-but it is not always feasible. Some here will say that your valve will blow-but cannot/will not answer why backhoes, logsplitters and solenoid valve are fine to hook up without PB connections.

Northman info shows back pressure rating for return flow @ 2350 max....because of the design of the valve (mechanically sealed between core and soleniod)....

Gresen mobile valves (sp series) shown here (http://www.parker.com/literature/Hy...ce Literature/Bul HY14-2715-M1 SP SPK SSK.pdf) show on page 8 a cutaway view of a standard mobile valve...notice the seals on each end of spool (item #6)....that oring sees all the back pressure downstream in return port......

if you don't use PB then those 2 seals see all pressure downsteam while operating anything after this first valve....resulting in valve failure prematurely....

also if you link up several standard valves (similar to gresen sp series) in series w/o PB then the pressure in the second valve will be additive to the first valve...potentially resulting in catastrophic housing failure in the first valve if both valves are being used at the same time at full pressure....

the gresen breakdown also show good cutaways of "open center, power beyond plug & closed center plugs".....excellent way to see it in picture form rather than schematic form....

Bill

 

[wvpolekat]

It seems to me that ANY spool in the pressure side of the circuit would have to hold the max pressure that is seen. Otherwise, all your cylinders would extend when you lift your ballast box on your 3pt. I could be way wrong, but something has to isolate the system pressure from circuits not in use and I assume that is the valve.

Now, without PB and just using open center, if I am moving the grapple, the 3pt would not get the same (if any) flow it would otherwise. But, I am willing to accept that since I don't see many situations where I need to raise the 3pt and open or close the grapple at the same time. I CAN see me using the lift and curl at the same time.

If it comes down to it, I will replace the solenoid valve with a manual valve with PB and chock it up to experience.

On a related note, I went to Lowes today and picked up some 1/2x2" grade 8 bolts and some 1/8 steel to work on my valve mount. Also picked up some primer and "autumn crush" orange paint to get the raw steel painted. Picked up a 120 grit flap wheel for the grinder too.

 

[kennyd]

Northman info shows back pressure rating for return flow @ 2350 max....because of the design of the valve (mechanically sealed between core and soleniod)....

Gresen mobile valves (sp series) shown here (http://www.parker.com/literature/Hy...ce Literature/Bul HY14-2715-M1 SP SPK SSK.pdf) show on page 8 a cutaway view of a standard mobile valve...notice the seals on each end of spool (item #6)....that oring sees all the back pressure downstream in return port......

if you don't use PB then those 2 seals see all pressure downsteam while operating anything after this first valve....resulting in valve failure prematurely....

also if you link up several standard valves (similar to gresen sp series) in series w/o PB then the pressure in the second valve will be additive to the first valve...potentially resulting in catastrophic housing failure in the first valve if both valves are being used at the same time at full pressure....

the gresen breakdown also show good cutaways of "open center, power beyond plug & closed center plugs".....excellent way to see it in picture form rather than schematic form....

Bill

Yup, I understand all that.

Does not change what I wrote one bit though. Can you show me ANY threads with blown up or cracked valves?

 

[wvpolekat]

Couple of questions, just trying to understand.

Gresen mobile valves (sp series) shown here (http://www.parker.com/literature/Hy...ce Literature/Bul HY14-2715-M1 SP SPK SSK.pdf) show on page 8 a cutaway view of a standard mobile valve...notice the seals on each end of spool (item #6)....that oring sees all the back pressure downstream in return port......

if you don't use PB then those 2 seals see all pressure downsteam while operating anything after this first valve....resulting in valve failure prematurely....

In a PB setup, what isolates the PB port so that it does not see this pressure?

also if you link up several standard valves (similar to gresen sp series) in series w/o PB then the pressure in the second valve will be additive to the first valve...potentially resulting in catastrophic housing failure in the first valve if both valves are being used at the same time at full pressure....

Not sure I follow this one. Pressure should not be additive, if you connect 2 hoses together with 2500 PSI in them, you don't get 5000 PSI, you would still have 2500 PSI. Can you elaborate on the situation you are describing?

 

[wdchyd]

Couple of questions, just trying to understand.


In a PB setup, what isolates the PB port so that it does not see this pressure?

Not sure I follow this one. Pressure should not be additive, if you connect 2 hoses together with 2500 PSI in them, you don't get 5000 PSI, you would still have 2500 PSI. Can you elaborate on the situation you are describing?

if you scroll down to pages 29, 30, 31 you'll see where use of three different plugs/sleeves are use to concert to "closed center, power beyond & open center) I know it hard to visualize but they do it in the casting of the valve, the cutaway pictures are probably the best I've seen to understand....

As far as the excess pressure don't forget "Pressure Intensification"....you are dealing with potential exhaust pressure coming from cylinder exhaust...(http://www.insidersecretstohydraulics.com/cylinder-intensification.html)

if there is blockage downstream (i.e. valve being used downstream) it can intensify

Couple of years ago I was called out to a customers place where several SP Gresen valves (4) were set up in series with no PB (original from factory)...these were used for overhead hopper doors at a wood chip plant...while another valve downstream was being used by someone else, the first valve housing cracked instantaneously (while no one was hurt, it did oil the driver and inside his truck as the valve was being operated at his truck window)

 

[wvpolekat]

Ok, I understand the pressure intensification. Thanks for the link.

Now, as this applies to me, since my loader valve has a "Tank" port for waste oil, would that negate this risk for me? At least due to the valve I am installing on the PB port?

Or, is the concern further down at the 3ph? Would it be subject to the risk of pressure intensification because it is a SA cylinder (I think)?

Would the "prudent" thing to do be to NOT try to use the 3ph and grapple at the same time? Perhaps a diverter valve on the PB port of the loader valve so you have to choose grapple or 3ph?

Is it acceptable for the last item in the chain to be a regular open center valve?

 

[wdchyd]

Not sure I follow this one. Pressure should not be additive, if you connect 2 hoses together with 2500 PSI in them, you don't get 5000 PSI, you would still have 2500 PSI. Can you elaborate on the situation you are describing?

Well the info on the web is not at my finger tips as of yet, but when you stack up a relief valves in a series connection (with the exhaust of the first PRV going in to the second)the pressure adds up accordingly....

Vickers does this on Pressure compensated Piston Pumps, they set low pressure PRV at the compensator, then add remote PRV downstream on exhaust port (not to tank) to increase pressure to be added increasing pressure output on pump.....

 

[J_J]

The simple fact is that no subplate for a solenoid valve comes with a PB connection.

The "ideal" way is to use a PB equipped valve whenever possible-but it is not always feasible. Some here will say that your valve will blow-but cannot/will not answer why backhoes, logsplitters and solenoid valve are fine to hook up without PB connections.

With all due respect,

I simply do not understand why you insist that it is Ok to put all valves in series. The output pressure on the return port on a log splitter is not that critical. Some valves you can, because the input and output ports are built to take the pressure. I am sure you have read the specs on a lot of valves, and noticed that the input and output valves had different psi ratings. Maybe things have not split or cracked for you, but I am sure they do for others, and there have been reports of damage valves on TBN and other sites. I have talked to the Prince engineers, and local hyd technicians, and they all agree. The point is, that some valves can have the same input and output pressure, and others do not. The statement that you made about some on here, [ that valves will split ], is not what we said or I said. The word is could split or crack.

All PBY ports should take the same pressure as the input port.