Third function dirverter valve vers True 3rd function valve

[powerscol]

OK folks - been doing some reading and I am finding two different terms being used. One is a diverter valve to create a 3rd function and the other is a true 3rd function valve. In looking at pictures some have one solenoid and other have 2 - usually in a grapple set up. I am just doing research trying to understand function and placement. I have a hay grapple running off of rear remotes, It takes an A_B circuit, In other words push lever one way to hook and pull back to unhook. Im planning on getting a rear blade that can take up to 3 remote sets to operate (swing, tilt and offset) I would also like to keep my hydraulic top link, so I know out back I need at least 4 sets. It would be possible I need 5 if I use the blade as ballast while moving hay.


So in looking at various pictures here I think I would need a twin solenoid set up like several sell here. There should be 2 input ports and 4 output ports, one set goes to the original function and the other two controlled by the solenoids to act like a A-B pair using 2 buttons mounted somewhere on the joy stick, or a replacement head with the buttons built in. Now I have no clue what a single solenoid would be used fore up front but found pictures on the net.

Question 1 - what is the difference between a diverter set up and a true 3rd function set up?

Question 2 - In what circuit is the set up normally placed. Loader lift function, or curl function?

If I understand the operation I might use the curl to set the grapple over the bales, then to hook up the Bales press the button while moving the joy stick to lower the loader to operate if the 3rd function was installed in the loader up/down circuit. Am I understanding this correctly? To unhook would I be pressing a button while pulling back on the loader control, or would it still be forward - or does it matter which way the flow is coming?

Thanks for any help or links that might explain this better.

BTW this is a great place to spend time reading and learning when you can't do anything else I had a rotater cuff and bicep repaired, so not much I can do. I tore it loosing the world arm wrestling championship :confused3::laughing: So far so good - PT is a real H*$$ as they work to get full motion back. I love the stim treatment (electric shock pads) and ice pack though after everything is over.

 

[Sysop]

Question 1:
Basically, a true third function has two switches; one to extend a cylinder, the other to retract it. When you press one of the two buttons, one of the two solenoids opens a valve to actuate the cylinder.

A diverter is going to have one button. When you press it, it switches the flow path from the "diverted" function to the 3rd function ports. You then move the existing lever one way or the other to activate flow at the 3rd function ports.

The main differences are:
-With a diverter, you are disabling one of the functions when the button is pressed, but you can feather the lever to adjust the flow and pressure. A skilled operator could use a grapple to take hold of someone's hand without crushing it easily. (hush up safety police)
-With a true 3rd function, as long as you are feathering the controls enough to still have flow at the power beyond, you can operate all three functions at once. You have no control over the speed or pressure it operates. There is a high probability even a skilled operator would crush a persons hand if they tried to take hold of it with a grapple. (again, hush up safety police)

For some people, diverters work best, for others, 3rd function. I think the most popular opinion is that a skilled operator can be slowed down with a diverter and there is little downside to a 3rd function. But if you occasionally want to clamp down on pallets or pipes or other things that could be damaged, a diverter is the way to go.

Question 2:
3rd function goes on the power beyond port of the loader valve.

Diverter can go on either curl or lift, whatever will work best for your uses. If I were going diverter, it would likely go on my lift circuit so I can curl/roll a grapple while gently pinching down on something precisely.

 

[RNeumann]

The true third function comes off the power beyond from the loader valve or rear remotes (depending on how it's plumbed) and allows you to lift, curl and 3rd function at once. This setup has 4 ports- power beyond in and out and 2 flow ports.
The diverter valve goes between the loader control valve and (typically) the curl cylinders. When you activate the diverter you lose curl and those same loader controls now control the third function. This isn't true third function since it doesn't allow curl at the same time. This setup has 6 ports. 2 in, 2 to curl cylinders and 2 to third function.

The true third function valve is closed until you press the button. One button sends fluid in one direction (say open a cylinder) and the other button sends the fluid in the opposite direction (say close a cylinder).

One of your rear remotes can be used as a "third function" by running the hoses from the back to the front. With this setup you would have one hand on the loader joystick and then use your other hand to control the third function. Personally this would drive me nuts! But several on here not only do this, but like it.

If you want a nice valve for the third function check out the Hyvair DO3 or DO5 depending on flow requirements. This style valve (all brands) can run warm so over sizing isn't a bad thing if you have the room.

Good luck.

Edit- looks like Sysop and I were typing at the same time.....

 

[powerscol]

Excellent information - Thanks. This old guy thinks he understands now, This really helps in my quest, RNeumann - I currently have lines to the front from the rear remotes, so your suggestions makes sense, I don't believe my Bobcat CT 235 has a power beyond port, so Ill keep looking into the diverters - especially as I have the lines to the front already. When I add my additional remotes to the back I might set out up a dedicated one to the hay grapple on a rocker switch. Another cup of coffee and Ill do a bit more thinking, Supposed to rain today, so not much else to do but taxes.

 

[RNeumann]

The lines to the back must go into a valve. That valve should have Power Beyond (PB). So you should be able to come out of the rear valves and into the front control.
Based on what you are describing google "stackable hydraulic valves" You can add a bunch of valves together at meet all your needs. Some can be electric over hydraulic (what you are describing for the third function) while other can have control levers right on the valve.
Bucher and Prince seem to be the common brands.

 

[AKfish]

Excellent information - Thanks. This old guy thinks he understands now, This really helps in my quest, RNeumann - I currently have lines to the front from the rear remotes, so your suggestions makes sense, I don't believe my Bobcat CT 235 has a power beyond port, so Ill keep looking into the diverters - especially as I have the lines to the front already. When I add my additional remotes to the back I might set out up a dedicated one to the hay grapple on a rocker switch. Another cup of coffee and Ill do a bit more thinking, Supposed to rain today, so not much else to do but taxes.

There's another approach that you might consider in lieu of the electric diverter and selenoid configuration i.e. (Fasse valve). Utilize a power beyond (PB) circuit and several open-center block (spool) valves that are plumbed into the PB circuit.

Your FEL is configured with 2-open center spool valves for boom and curl function. They are mechanically operated via the cables from the joystick. Hydraulic fluid flows continuously from the pump through the valve and back to the sump. When you move the joystick the fluid is directed to a port in the valve by a machined spool to move either the boom or curl cylinder.

A "real" dedicated SCV works this way in an open-center hydraulic system. The rear mounted SCV is an open-center spool valve that has a mechanical control linkage similar to your FEL system.

I installed a rear fender mounted block valve with a single-lever control routed thru the PB circuit to control a hydraulic top link on the 3pt.

I have also seen folk's here on TBN use this configuration for multiple, single lever controls. Of course, the complicating factor with this approach is the necessity of routing additional hyd hoses for every cylinder you want to use.

A major advantage is you won't be "switching" your existing hyd functions on and off; on and off. And forgetting which function is on and which is off and fumbling with switches and rocker switches and looking for a light that indicates what hyd functions are on... In the heat of working and if you have a mini or a major catastrophe - the last thing you want is fumbling for a switch and switching the wrong d@mn one!

(I have 2 tractors with multiple hyd functions controlled via electric diverter.). If I could convert those diverted hyd functions to direct controlled spool valves... I would - in a heartbeat!

 

[N2DFire]

Excellent information - Thanks. This old guy thinks he understands now, This really helps in my quest, RNeumann - I currently have lines to the front from the rear remotes, so your suggestions makes sense, I don't believe my Bobcat CT 235 has a power beyond port, so Ill keep looking into the diverters - especially as I have the lines to the front already. When I add my additional remotes to the back I might set out up a dedicated one to the hay grapple on a rocker switch. Another cup of coffee and Ill do a bit more thinking, Supposed to rain today, so not much else to do but taxes.

Hey man - sucks to hear about the rotator cuff - hope your rehab goes well & you heal up fast. Your CT235 is (from what I understand) pretty much a Kioti CK35 painted white. Just so happens I have enough knowledge about one of those to be dangerous.

The lines to the back must go into a valve. That valve should have Power Beyond (PB). So you should be able to come out of the rear valves and into the front control.
Based on what you are describing google "stackable hydraulic valves" You can add a bunch of valves together at meet all your needs. Some can be electric over hydraulic (what you are describing for the third function) while other can have control levers right on the valve.
Bucher and Prince seem to be the common brands.

Rneumann is right on track. The Power Beyond port on the loader valve has a Hard Line w/ banjo fittings that runs from the valve body to the rear of the tractor. This line provides the fluid flow for the 3pt lift (and in your case) the 2 factory rear remotes.

As Sysop been stated before you can install a diverter on the curl/dump function of your loader circuit or for a true 3rd function - this hard line is what you would split.

There are a few diverter kits & 3rd function kits on the market that are pretty much bolt-n-go. There were little things about each I didn't like so I ended up designing & building my own. I created a write-up here. Be sure to read thru the whole thread as this was a learning experience (and design on the fly) thing for me so I have some updates and "would have done different" scattered among the comments.

http://www.tractorbynet.com/forums/customization/358086-kioti-ck-35-3rd-function.html

As to your need for 4 rear remotes, I am still in the process of trying to get myself to buy the 2 remote factory kit (for a top-n-tilt set-up) and have been thinking about what I would do if I needed more remotes. I think a dual diverter setup could be done fairly easily and that would get you 4 functions; but I honestly have no idea what the factory rear valves, plumbing, and mounting look like first hand so it may be a huge pain too.

Best of luck in your research & project.

 

[LD1]

In regards to question 2, about using curl or lift for a diverter....

On my machine I had no choice. I HAD to use the lift circuit. My loader valve in "dump" mode is regen only. Meaning it puts pressure out BOTH ports. This causes the curlcylinders to extend due to the difference in piston area, however at a much less force. No problem on a loader dumping as you have gravity helping. But a grapple that needs the force, it dont work well. And a pair of single acting cylinders like angle on a snow plow, it just wont work at all.

Some loaders have a detent in the curl where you have both normal and regen as options when dumping. IF regen happens to be the first detent and you have to push further to get to normal mode, I dont think I would like that on a diverter either. It limits the feathering ability. And for grapple work anyway, I like it on the lift/lower. For the snowplow, I would prefer it on the curl so the left-right movement of the joystick would correspond with with movement of the plow, but it is what it is.

 

[ovrszd]

I'll add a bit of clarity that applies to 90% of tractors. If someone has a different scenario, clarify it for knowledge sharing.

Tractor hydraulic pump output goes to FEL valves, if no demand it then PB's to rear remotes, if no demand it then PB's to 3pt.

If you add diverter for 3rd function it simply switches the path of that circuit between lift/curl of the FEL to 3rd function. All other subsequent paths I mentioned above stay the same.

If you add "true 3rd function" it is added just after the FEL valves PB. So now your path is pump to FEL, PB to 3rd function, PB to rear remotes, PB to 3pt.

If your tractor has adequate flow it can perform FEL lift, FEL curl and 3rd function. Any pressure applied beyond that will be minimal at best. So in the case of my M9540 with true 3rd function I can lift, curl, grab and still get slight action out of one rear remote. Other two rear remotes and 3pt won't move at all until actions start ceasing in the beginning of the "chain". As each of those actions cease power is increased to the next action in line.

From what I've read here on TBN smaller tractors struggle to truly use 3rd function. They just don't have enough flow to do that. Those tractors might be better served using a diverter?

 

[ericm979]

That's a really good point.

I have some hydraulic novice questions:

Is there a way to calculate "reserve capacity" when operating the FEL to see if the tractor has enough GPM to operate the loader and 3rd function simultaneously? Like by taking the cycle time of the loader cylinders and their volume to calculate how much fluid they use per second?

Is the chain a strict priority? I.e. cylinders on the first valve get all the flow they can use and only the remainder goes to the next in line? Or are the connections from one valve in the chain to the next more like a tee, so cylinders on the first and second valves share flow equally? Or some combination of the two depending on flow restrictions in the system? Maybe it does not matter.