Alternative third function

[npalen]

With open center systems, that's not possible if you add on a valve; the first valve in the "chain" takes all of the juice. Some valve blocks can allow some semblance of operating simultaneously, however.

Would you not be able to operate both valves simultaneously if the "first" valve is being feathered and still allowing excess flow to "power beyond" to the second valve. It seems that if the first valve is opened only enough to use half of the pump output then the remainder has to go somewhere which would be out the PB port to the second valve.

The two valves (or spools in the same valve) in mind would be the bucket and grapple functions. I just asking as I don't fully understand.

Edit: The attached pic shows the third function in the same valve.

 

[4570Man]

Would you not be able to operate both valves simultaneously if the "first" valve is being feathered and still allowing excess flow to "power beyond" to the second valve. It seems that if the first valve is opened only enough to use half of the pump output then the remainder has to go somewhere which would be out the PB port to the second valve.

The two valves (or spools in the same valve) in mind would be the bucket and grapple functions. I just asking as I don't fully understand.

Not very good. The lower pressure of the two tends to get all the flow.

 

[npalen]

Not very good. The lower pressure of the two tends to get all the flow.

But wouldn't it be the same as feathering a joystick to give lift and bucket functions simultaneously?

 

[ovrszd]

But wouldn't it be the same as feathering a joystick to give lift and bucket functions simultaneously?

Yes. The pump isn't intelligent. It simply provides flow which builds pressure until the flow rate reaches it's capacity, then no pressure is created. So, if the first valve doesn't use it all there is pressure created in the second, etc., etc.

This principle is why higher pump flow on bigger tractors can run more functions at once.

This can be demonstrated by lowering your 3pt. Then lift/curl your FEL. while that is happening also lift your 3pt. Action there will be very slow if any. Release the FEL control and watch how quickly your 3pt responds.

 

[npalen]

But if you feather the loader valve using half of the pump output would the 3PT hitch raise at roughly half speed?
My intent here is not be argumentative, just needing help to get this clear in my mind. Thanks.

 

[ovrszd]

But if you feather the loader valve using half of the pump output would the 3PT hitch raise at roughly half speed?
My intent here is not be argumentative, just needing help to get this clear in my mind. Thanks.

No argument at all.

Yes, in theory. There are some variables. But generally, yes.

I have what's known as true 3rd function on my Kubota. A solenoid operated valve plumbed after the FEL valve. My tractor has enough flow to perform all three functions at once. I've never tried the 3pt test to see if it will move at all. I'm guessing it would be pretty slow.

With small tractors and low pump gpm I believe a diverter valve is the best setup. At no time are more than two functions activated at the same time. Learning to push/release the diverter button to switch from 3rd function to curl function and back is easily learnable. Many, many guys here on TBN use this system and highly recommend it.