Example: Rear remote valve with NO "Power Beyond"

[Sodo]

After a lengthy discussion with knowledgable TBN members (Bukitcase, RSwyan, J_J & others) I finally understand this "problem". Many thanks for their persistence.

A tractor can work for years with no "Power Beyond" circuit (PB) on a remote, but understand that the valve seals are at risk whenever the 3-point is loaded (or topped out, anything causing upstream pressure). Keep in mind that the 3-pt hitch lift is almost always the last device in the circuit & doesn't have PB because it's the last device. But every valve upstream of the 3-pt requires a PB port, and a direct, low-pressure return to the tank.

It does not risk the internal spools, or crack the valve casting - the problem is that without a dedicated return to tank, it over-pressures the external seals.

Here is a pic of a tractor with a heavy 3-point attachment (the 3-pt forklift). You can't see it , but this tractor (currently) has no PB circuit on the remote valve - thus is "at-risk". The forklift's weight on the 3-point causes high pressure on the external seals of the (upstream) "remote hydraulic" valve. Which "may or may not" cause a problem, as long as the levers on the valve upstream are never "moved" while this weight is on the 3-point. While the 3-point load is pressuring the external seals, moving any lever (sliding a spool) could blow the external seals right then and there.

Here is a diagram showing a hydraulic remote with NO power beyond circuit.
The blue "DROPLETS" are the (upstream) remote valves external seals blowing oil due to pressure or weight on the 3-pont lift (downstream).

This took a long time for me to understand, until I saw the diagram.



Then it was "easy" to see, and I hope this diagram helps others.
Also this is about 95% of what I know, period.
Possibility that I'm missing something (,,,Steve says I'm a new "expert") is very likely.
Further explanations, corrections, (and correct terminology) is appreciated.

:thumbsup:

 

[BukitCase]

Cool pic-chur, wher'ja find it??

Sounds like yer gittin' more "experter" :thumbsup:

I was gonna draw something like that one from Prince, then remembered I'd seen that one somewhere and went "researching" - I've already bought a fair amount of Prince stuff between the two tractors, hoe, etc, so hopefully they won't get upset with my "research" (Also known as "Xerox Engineering")

Like your new "Krof lift" ... But since I'm gettin' to dang old for my head to "go all Linda Blair" and still function, I'm keepin' my eyes open for a smaller propane powered regular one for the new shop... Steve

 

[Harry in Ky]

You're not alone in having a hard time understanding the logic of power beyond. There are a great number of valves out there plumbed with only two hoses, which their owners claim "it's been that way for years", therefore it can't be part of their current problem. I've pointed this out on any number of threads on this and other forums, only to be pretty much ignored, so I've learned over time to not bother trying to explain it any more.

 

[J_J]

After a lengthy discussion with knowledgable TBN members (Bukitcase, RSwyan, J_J & others) I finally understand this "problem". Many thanks for their persistence.

A tractor can work for years with no "Power Beyond" circuit (PB) on a remote, but understand that the valve seals are at risk whenever the 3-point is loaded (or topped out, anything causing upstream pressure). Keep in mind that the 3-pt hitch lift is almost always the last device in the circuit & doesn't have PB because it's the last device. But every valve upstream of the 3-pt requires a PB port, and a direct, low-pressure return to the tank.

It does not risk the internal spools, or crack the valve casting - the problem is that without a dedicated return to tank, it over-pressures the external seals.

Here is a pic of a tractor with a heavy 3-point attachment (the 3-pt forklift). You can't see it , but this tractor (currently) has no PB circuit on the remote valve - thus is "at-risk". The forklift's weight on the 3-point causes high pressure on the external seals of the (upstream) "remote hydraulic" valve. Which "may or may not" cause a problem, as long as the levers on the valve upstream are never "moved" while this weight is on the 3-point. While the 3-point load is pressuring the external seals, moving any lever (sliding a spool) could blow the external seals right then and there.

Here is a diagram showing a hydraulic remote with NO power beyond circuit.
The blue "DROPLETS" are the (upstream) remote valves external seals blowing oil due to pressure or weight on the 3-pont lift (downstream).

This took a long time for me to understand, until I saw the diagram.



Then it was "easy" to see, and I hope this diagram helps others.
Also this is about 95% of what I know, period.
Possibility that I'm missing something (,,,Steve says I'm a new "expert") is very likely.
Further explanations, corrections, (and correct terminology) is appreciated.

:thumbsup:

What do you know about this tractor setup with forklift?

Is he using the 3pt to raise and set the forklift?

Is he using another set of valves maybe loader valve or remote to operate the forklift cyl?

Could he be using a splitter at the back feeding some to the 3pt and the remainder of the flow to the lift?

Do you think he has it plumbed correctly?

 

[Sodo]

Harry, It's confusing because the problem culminates when two events overlap (happen at same time).

1) there is a heavy weight on the 3-pt, over-pressurizing the valve seals
----- AND -----
2) the operator moves a valve lever (sliding a valve while its seals are over-pressurized)

If the valve lever is not moved at this time, its possible that the valve can handle the over-pressure, maybe forever. So lots of tractors survive it. If all your 3-pt ever lifts is a 400 lb bush hog, maybe you will never have a problem.

I can see how lots of valves survive. My valve is (currently) fine, but it's not proper hydraulic design. Until I locate a PB adapter & re-plumb you can bet I'll be cautious moving my remote valves when there's weight on the 3-pt.

Understanding the "Power Beyond" problem was a goal, and for that I'm happy!

========

J_J we're posting at the same time. It's my tractor and its NOT plumbed correctly. Its plumbed like the princehyd diagram above. Now that I "understand", the only time I'd use the rear remotes is when the forklift is sitting on its own wheels, on the ground (no weight on the 3-pt). Incidentally the forklift attachment is not yet functional.

I'm hoping to find a PB adapter for the Dinoil remote valve (but not much luck yet). Will try to find a partnumber on the valve. If you can recommend someone who knows a lot about Dinoil valves it would help me a lot 'cuz I can't find anything.

 

[J_J]

This is the Dinoil valve installed by flusher and he says his tank line goes to tank.

I am curious what feeds the 3pt input.

http://www.tractorbynet.com/forums/kubota-buying-pricing/133216-remote-hydraulics-l3240.html

BONDIOLI & PAVESI

Dinoil specializes in the design and manufacture of directional control valves, which are widely applied in agriculture, construction and earthworks. DINOIL joined the Group in 1986. In addition to providing standard products, Dinoil can develop products to suit customer-specific applications, in accordance with the Bondioli & Pavesi philosophy of close collaboration with customers

I believe the tank line ratingis about 750 psi.

You can protect your valve by using a check valve or a switching valve or a splitter valve.

1/2" NPT 30 GPM SINGLE SELECTOR VALVE PRINCE RD950.