The Confusion of Tractor Hydraulics Terms and the Quality of Different Choices.

[J_J]

The learning problem in hydraulics is with the individual.

There is enough subject matter out there to learn what you want to know.

DVD, Books, Internet, etc.

I don't believe there is any real definition to 3rd function. People have used it to explain the third part of something.

If a 3rd function was first in the flow path, is it still the 3rd function?

How many 3rd functions do you want, or need. You really need to know what each hyd component does

When you activate a 3rd valve, the pump flow goes through the valve to the hyd components it is controlling.

There are many hyd glossaries available to help one understand the terms.

If you need clarification, just ask, and someone will be glad to explain their version.

 

[AxleHub]

If you are running a grapple, or anything else off the rear remotes, I prefer them be called as they are......rear remotes. As I think THAT is less confusing than calling it a 3rd function.

Imagine a newbie sees you have a grapple lowered via 3rd function valve and wants to do the same. Then you have to get to explain that you are running your grapple off the rear remotes, and just calling it a 3rd function.

To run anything on the front off the rear remotes isn't confusing at all. It is a remote valve by definition, located at the rear of the tractor.

You can have front remotes as well (to further confuse the masses).

What makes a 3rd function and diverter different is they are controlled with a button usually, located on the joystick of the loader. Thus 3rd function meaning you have controlls to 3 functions right there at the joystick. All 3 can operate at the same time with a 3rd function valve, or you can have a diverter, which permits the operation of two at a time. (But not the same two tied to the diverter.)

I didn't make up the terminology. But understand it and am trying to explain it. Back to the point of you calling your grapple control CIA rear remotes as a 3rd function....vhen searching for kits and parts...look at what the sellers/mfg call things. Rear remotes, 3rd function kits, and diverter kits are 3 different things

LD1 , I think that post was a very good one for clarifying the 3 categories.

So both 3rd function and diverters are all primarily electrical switch cobtrolled at the joystick. Do allnof them require a replacement joystick customized for the switch ?

 

[k0ua]

LD1 , I think that post was a very good one for clarifying the 3 categories.

So both 3rd function and diverters are all primarily electrical switch cobtrolled at the joystick. Do allnof them require a replacement joystick customized for the switch ?

Not necessarily, some just fasten the switch module on with tie wraps or something simple like that. It can be as customized as you desire.

 

[SPYDERLK]

Thus 3rd function meaning you have controlls to 3 functions right there at the joystick. All 3 can operate at the same time with a 3rd function valve, or you can have a diverter, which permits the operation of two at a time. (But not the same two tied to the diverter.)

I didn't make up the terminology. But understand it and am trying to explain it. Back to the point of you calling your grapple control CIA rear remotes as a 3rd function....vhen searching for kits and parts...look at what the sellers/mfg call things. Rear remotes, 3rd function kits, and diverter kits are 3 different things

How can you operate 3 at the same time? ... careful feathering of 3 valves simultaneously? ... split flows? ... separate hyd supplies? :confused2:

 

[CalG]

How can you operate 3 at the same time? ... careful feathering of 3 valves simultaneously? ... split flows? ... separate hyd supplies? :confused2:

Joy sticks! such as a Backhoe might be fitted with. Though with a bit a practice, real production can come out of a gang of single levers.
Old school, but you learn to use palms and finger tips to get the swing and bucket to dump just right. ;-0

 

[LD1]

4-stick on my old Ford. Sometimes I operate all 4 at the same time;

 

[SPYDERLK]

Joy sticks! such as a Backhoe might be fitted with. Though with a bit a practice, real production can come out of a gang of single levers.
Old school, but you learn to use palms and finger tips to get the swing and bucket to dump just right. ;-0

4-stick on my old Ford. Sometimes I operate all 4 at the same time;

So then; that makes it important to not even introduce the idea of 3rd function control by an electric switch if you are claiming the ability to control multi functions simultaneously. ... Once that switch is thrown your available pressure will be limited to the resistance of that load instead of by a variable critical orifice.

 

[J_J]

You can operate as many valves as the flow will allow.

In open center hyd systems, if you use only part of the flow for one thing like a loader, the rest of the flow will go downstream.

In closed center hyd systems, each valve will share the flow and decreased speed will be observed.

When the 3rd function valve is opened, the hyd components uses the fluid and passes the pump flow available downstream.

So the flow through a 3rd function valve is either pump flow or flow from the cyl controlled by the 3rd function.

Cyl expended fluid from loader cyl flows only to tank.

If the loader uses all pump flow, then the cyl flow will go to tank and none left for the next valve.

 

[AxleHub]

Can someone define what a closed center hydraulic system is vs an open center system?

And what type of system do scuts and small cuts use as they are the primary focus of the thread ?

 

[k0ua]

Can someone define what a closed center hydraulic system is vs an open center system?

And what type of system do scuts and small cuts use as they are the primary focus of the thread ?

I will take a shot at it, but keep in mind who you are listening to, as I have zero qualifications.

In an open center system, a fixed displacement pump has a constant flow rate and that flow of fluid is going thru all of the valves all of the time. The fluid is flowing thru the valves when they are centered and on to the next valve, eventually returning to the tank. So the fluid is constantly being circulated thru your system when your hydraulics are doing nothing. This is the type the vast majority of CUTS and SCUTS have.

In a closed center system you have a variable displacement pump that the flow rate varies from zero to maximum rated flow. The fluid is not circulated thru the valves at all times. From what I understand, these types of pumps can maintain full pressure at zero flow rate. On a typical valve if you move the valve from center to direct flow to a work port it will apply the pressure to that work port and the fluid from the other side of the cylinder will flow to the tank of course just like an open center system. The other valves are not plumbed in series, but will have a pressure and tank connection of their own. I hope I have not spewed a bunch of half truths here, perhaps JJ can comment on this. I have no experience with closed center systems. Every tractor I have ever owned is open center.