3 Point Hitch Lift Control on Kioti LK35

[J_J]

Very simply, as the flow must pass through the needle valve to get to the 3pt.

If you screw down the needle valve to supply only 3 GPM to the 3pt, you have put an orifice in the fluid path, and if the pump is trying to run at max, then the FEL relief might relieve.

One leg of the splitter type valve will flow whatever to the 3pt and the rest of the flow will go to tank, allowing full flow through the FEL valve.

The relief might go off anyway as you have blocked most of the pump flow. The FEL should operate fully as the cyl flow flows trough the OUT port.

If you feather on the FEL, then the valve might relieve.

 

[Tx Jim]

J_J
If a fiels installed needle valve in front of 3 pt is tightened down to limit flow won't the excess flow of pump be sent to sump by way of the FEL valve return ports? If this isn't true then what is the need for 2 return ports(sump & PB) on a FEL valve?
Thank You,Jim

 

[Fallon]

Dropping engine RPM down to an idle would lower pump flow a bit.

 

[k0ua]

J_J
If a fiels installed needle valve in front of 3 pt is tightened down to limit flow won't the excess flow of pump be sent to sump by way of the FEL valve return ports? If this isn't true then what is the need for 2 return ports(sump & PB) on a FEL valve?
Thank You,Jim

Jim keep in mind that the hydraulic cylinders on the lift and the curls are double acting. so when you pump fluid in the extend port of the lift cylinders for example the fluid on the retract port side of the cylinder goes to the sump. But the only time that fluid can see the sump path is when you are activating the lift spool. Otherwise the flow path for the fluid from the pump to the FEL control valve goes out the power beyond port of the FEL valve. IF it could go to the sump you would never be able to develop any pressure on the 3pt because the fluid would take the path of least resistance and just dump into the sump. Does that make sense?. So the sump path is only open when one of the other functions is selected by the spools. Likewise when you lower the lift for instance the fluid you just pumped into the extend port now gets dumped into the sump when you move the spool to start pumping fluid into the other side of the cylinder. Of course the loader lift cylinders wont move either direction even with a fully loaded bucket if the spool is centered (within leakage limits of course).. Hope this helps

James K0UA

 

[J_J]

J_J
If a fiels installed needle valve in front of 3 pt is tightened down to limit flow won't the excess flow of pump be sent to sump by way of the FEL valve return ports? If this isn't true then what is the need for 2 return ports(sump & PB) on a FEL valve?
Thank You,Jim

The only purpose of an out/return port is to send cyl fluid to tank.

The PB sends any or whatever is not used by the FEL, be it partial flow or full flow downstream..

When the FEL valve lever returns to neutral, where do you think the full pump flow is going. It will try and go downstream.

If you restrict the flow, whatever can't flow through the orifice of a needle valve will go somewhere else.

 

[Tx Jim]

The only purpose of an out/return port is to send cyl fluid to tank.

The PB sends any or whatever is not used by the FEL, be it partial flow or full flow downstream..

When the FEL valve lever returns to neutral, where do you think the full pump flow is going. It will try and go downstream.

If you restrict the flow, whatever can't flow through the orifice of a needle valve will go somewhere else.

Ok I agree but unless I'm missing the light at the end of the tunnel I still can't figure out in my mind why the needle valve to control 3 pt speed can't be utilized. Please help me understand.Jim

 

[Tx Jim]

k0ua
Thanks but I understand hyd's but not near as well as J_J. I'm getting old but I'm no greenhorn when it comes to hyd's. I was employed by a JD dealer for over 21 yrs a lot of which was a dealer service manager

 

[J_J]

The other guy did this.

He used a flow divider valve like below to send controlled flow to the 3pt and the excess flow went to the tank.

The total flow from the pump is taken care of with none passing through a relief valve.

Dial it up or down as you prefer.

3/8 NPT HYD FLOW CONTROL VALVE W/RELIEF RDRS137-08

If you are running the engine at max for whatever reason, and producing about 12 GPM,

You could use a splitter/divider valve by sending priority flow to the 3pt and the rest of the flow to tank.

Here is a 3/30 GPM priority flow divider. 3 GPM will go to the priority circuit and the rest to the tank.

3/30 GPM PRINCE PRIORITY FLOW DIVIDER W/RELIEF

 

[k0ua]

k0ua
Thanks but I understand hyd's but not near as well as J_J. I'm getting old but I'm no greenhorn when it comes to hyd's. I was employed by a JD dealer for over 21 yrs a lot of which was a dealer service manager

OK that's cool, and I AM a greenhorn when it comes to hydraulics, my knowledge is all from reading, not practical experience. Now that said, let me try again, to help you understand. The worst that could happen is you ignore my explanation

The flow path comes from the pump to the FEL valve and out the Power Beyond port of the FEL valve (we are considering the FEL control to be centered, and this is an open center system). and NONE of the flow goes to the sump connection on the FEL valve. All of it goes to the PB port headed downstream to the next valve in series. If that next valve is the 3pt. lift valve then that is where the entire flow goes. It then goes thru that valve then into the sump. If you place a flow restriction like a needle valve to restrict the flow to the 3pt valve then pressure will build beyond the normal small amount of pressure that you have from the walls of the hoses, and the ports and connections. That pressure and restriction to the total flow from the pump would heat up the fluid and put wear on the pump and extract more power from the engine because the pump will be harder to rotate. It will not be within the design parameters that the engineers wanted thee pump to operate under.

The reason I am sticking with this, is because I feel responsible for the start of this discussion to begin with by my posting about the needle valve which was incorrect in Jeffs solution to the jerky hitch. He did NOT use a needle valve.

So I am going to continue to try to explain this until you are satisfied, or tell me to shut up I would be happy to call you on the phone and try to explain this better if you want to PM me with a number. I hope this helps.

James K0UA

 

[Fallon]

Ok I agree but unless I'm missing the light at the end of the tunnel I still can't figure out in my mind why the needle valve to control 3 pt speed can't be utilized. Please help me understand.Jim

Are you talking about putting the needle valve interrupting the flow in the power beyond loop, or between the 3pt control valve & the 3pt cylinders? In the power beyond loop would mess things up & restrict hydraulic flow to everything. I'm not aware of any issues other than slowness for a restriction after a work port.