3-Point Hitch top link hydraulics

[terry2shot]

terry2shot, you sound like you know what you're doing but I've never heard of putting closed center valves in an open center system, but, hey, I'm no expert.

Anyway, after re-reading my posts, I think I can sum it up much easier and that is, based on how the OEM Kubota valve is installed, you could remove the pipe that wraps around the back of the HST and connect your valve(s) in between the two end points for that pipe, then T or pipe the return to tank however you want. Hope any of this is helpful. Good luck.

Yes you can mix open and closed center valves in the same system. Now what is that hydraulic tubiing that runs behind the HST?. I was look'in at that.

 

[terry2shot]

Assuming that your tractor is OC and plumbed like most, your FEL valve does have a PB port, and that is what is returning to the run the 3pt hitch. The 3pt is last in line - typically there is a hydraulic connector block with a bypass switch - the switch allows internal running of the 3pt in one position, and runs accessories in the other, where pressure runs out to the accessories, then back to run the 3pt. You will have to re-route the FEL PB line (currently running back to the 3pt block) and run it to your remotes, then run the PB line from your remotes back to the 3pt block. You will have to tee-connect the tank return line from your remotes with the FEL tank return line.

Hope that makes sense.

JayC

YES....Thanks, this is what i'm looking for, but I do not unstand the bypass switch (some sort of a cartridge shuttle valve?). If the fel valve is power beyond..you should be able to run the 3pt at the same time (provided the volume is there). Now you can lock an cyl. with an open center valve by using a poc. (pilot operated check). this is common practice in the auto transport world and yes a plain open center valve (no check) allows a cyl. to "float". the work ports with the spool in the neutral position are open to tank.

 

[MtnViewRanch]

:thumbsup: I'm *trying* to learn... Don't know why this is so hard to sink in???


Now, that you mention it... the valve I bought says "Open Center Convertible to power beyond or closed center" (where is the icon of a guy hitting himself in the head with a mallet?? Insert it here ) :mur:
Surplus Center - 3 SPOOL 8 GPM PRINCE MB31BBB5C1 DA VALVE

Will a wall work? :laughing: With my thick skull, I broke the wall.

 

[terry2shot]

Maybe this link helps. I hope it works


Figure  4-143.  Open-Center Hydraulic System (Valve Closed)

 

[jgrreed]

Yes you can mix open and closed center valves in the same system. Now what is that hydraulic tubiing that runs behind the HST?. I was look'in at that.

OK, I too am trying to learn here, so read this with a chuckle....

You are obviously winning the 'credentials and experience' contest, but I have some fear for the life of the hydro pump on your tractor.

If you put an CC valve upstream of any other OC valves, when the CC valve is in the neutral position, will it not 'dead-head' the flow of the OC circuit, and cause the relief valve (if there's one there) to open?? This, in my mind, would cause a large amount of heat, and render your downstream OC valves useless. Also, will the dead-heading not put excessive, ongoing strain on the constantly running OC pump?

I'm hearing from your comments that you are set on this, so please, let me offer you the same advice I offer my Rodeo and Motocross athletes...... Get out there and giv'er, and lemme know how she treats ya, just don't blame me for the outcome. Is there a WTF emoticon??

AKKAMAAN, Kenny, DFKrug.....thoughts??

-Jer.

 

[kennyd]

All a closed center valve vs an open center is when a closed center valve is in the neutral position the work ports are closed off, effectivly (but not safely) locking the cylinder in position, an open center is well..open.

Terry, That is 100% wrong. That is techichally called a "tandem center" valve. The "open center" term is used generically here on TBN (and the the Surplus Center) to describe a valve that has the IN and OUT or PB ports "open" when the valve is in neutral. These type of valves are need when used with constant displacement pumps like we all have on out CUT's.

 

[kennyd]

I checked the manual and the ports that it shows are consumed by the FEL. Can I just "tee" those?

If you where such an expert, than you would know that you cannot Tee into high pressure hydraulic lines. ALL valve must be added in series, Tee'ing into the lines would put the new valve in parallel and since hydraulic fluid like electricity with take the path of least resistance then no usable pressure would be developed at either valve.

 

[kennyd]

Kenny, .....thoughts??

-Jer.

Given:thumbsup:

 

[terry2shot]

If you where such an expert, than you would know that you cannot Tee into high pressure hydraulic lines. ALL valve must be added in series, Tee'ing into the lines would put the new valve in parallel and since hydraulic fluid like electricity with take the path of least resistance then no usable pressure would be developed at either valve.

Kenny...chill, I never said I was an expert. I already admitted my mistake on the hp tee. what you are defining as open center is the same as I described in a previous post as open work ports. If I was the hydro guru I would not be asking questions. Also the oil still flow thru the outlet in the neutral position on a closed center valve just the spool closes off the work ports.

 

[teg]

Kenny...chill...

We all are trying to help... :thumbsup: Kenny is one of the best, IMHO

 

[Jay4200]

YES....Thanks, this is what i'm looking for, but I do not unstand the bypass switch (some sort of a cartridge shuttle valve?). If the fel valve is power beyond..you should be able to run the 3pt at the same time (provided the volume is there).

On my tractor, there is a hydraulic block - don't know exactly the right buzzword - that sits near the hydro filter. There is a switch/valve that turns with a screwdriver blade. In one direction it powers the 3pt hitch internally, but no accessories are activated. In the other position, pressure is diverted to a fitting, and return pressure must be applied to another fitting (the switch shorts these two nodes). The pressurized fitting powers the accessory or accessories, and PB from the last accessory comes back to power the 3pt hitch.

JayC

 

[kennyd]

Kenny...chill, I never said I was an expert. I already admitted my mistake on the hp tee. what you are defining as open center is the same as I described in a previous post as open work ports. If I was the hydro guru I would not be asking questions. Also the oil still flow thru the outlet in the neutral position on a closed center valve just the spool closes off the work ports.

Terry, I came off a little rough yesterday...I had a bad day and you where in the wrong place at the wrong time, sorry.

Now, you are still incorrect with that statement you just made.

Also the oil still flow thru the outlet in the neutral position on a closed center valve just the spool closes off the work ports.

Having the work ports closed (blocked) when the valve is in nuetral is defined as a "Tandem Center" valve, NOT Closed Center. This is the confusion that you started, and I am just trying to clear it up. I understand what you are saying-But I want to keep the terminology correct so as not to confuse others reading this. I you ordered a CC valve from the Surplus Center-you would fing out very quickly that is would not work.

The Open Center valve that you are describing (where the work ports are open to the tank when the valve is in nuetral) is more commonly called a Motor Spool valve.

 

[kennyd]

We all are trying to help... :thumbsup: Kenny is one of the best, IMHO

Thanks Teg

 

[kennyd]

On my tractor, there is a hydraulic block - don't know exactly the right buzzword - that sits near the hydro filter. There is a switch/valve that turns with a screwdriver blade. In one direction it powers the 3pt hitch internally, but no accessories are activated. In the other position, pressure is diverted to a fitting, and return pressure must be applied to another fitting (the switch shorts these two nodes). The pressurized fitting powers the accessory or accessories, and PB from the last accessory comes back to power the 3pt hitch.

JayC

This does not exist on the smaller series 'bota's.

 

[terry2shot]

Cool Ken lets start over..I'll post some schematics (if i can figure out how)..I work with curtiss wright and bucher valve manufactures. This is the terminology we've always used. The "closed center" valve and open center valve as I know it is as we were discussing is closed or open work ports with the spool in the neutral position. oil still flows thru to the outlet port. The closed center does not mean a "dead end" for the flow when the valve is in neutral. We build stacks combining both of these to lock hydraulic motors (closed center)and run our cylinders which are mainly self locking (double internal po checks), so we use an open center. But on the cheaper cylinders (mainly horizontal application) we will just use a closed center valve. Anyways. I'll try to stick to the familar terminology. Sorry for the confusion. All I want to do is add a (3) to the rear of my kubota. This should be simple if I could figure out the kubota hydro circuit(s)

 

[terry2shot]

lets try this, as you can there are what I refer to as open and closed centwer valves in the same stack

 

[Jay4200]

This does not exist on the smaller series 'bota's.

'Kay. Never saw one of the bitty guys (close up) in real life.

JayC

 

[terry2shot]

Found it.....Sorry for the confusion. What I was refering to a closed center is what is known as a tandem center outside of my company (and vendors).



TANDEM CENTER VALVES
Tandem center valves when in a neutral position by passes the flow of hydraulic oil to the return line. This is used to hold the cylinder/piston in position with no load on the pumps. When this system is the pump is running constantly to keep a ready supply of hydraulic oil, but as long as the cylinder/piston is not in operation the pump is working under no pressure or load. This system keeps wear and tear on the pump down to a minimum.

OPEN CENTER VALVES
Open center valves are the same as the tandem center, except that in the neutral position all lines are connected back to the reservoir. The primary use of this system is to prevent "shock" loading when the valve is placed in neutral. This takes pressure off the motor. This system is used in situations where the operating device needs to be moved by hand.

 

[jgrreed]

Wow, that is confusing. I can see where the conflicting ideas came from.

Hydraulics are confusing enough without having to learn 2 different languages!!

-Jer.

 

[CHDinCT]

terry2shot, are you still looking into how to tap into your BX hydraulics for you remote valves? I ask because I was looking at the installation manual for a Woods BH6000 backhoe that mounts up to a BX and it shows how they install the power beyond loop for the BH into the existing hydraulic block. It seems you could work off those schematics and just put your valve(s) in the loop with a return to tank hook up. Pretty clear pic's. I saved the pdf so if you are interested, I could post it here for your review.

Now, don't ask me why I was looking at how to plumb in a BH