Flow control valve for power beyond supply for loader?

[MechanicalGuy]

Hello. I'm looking to put a needle flow control in the line going to my loader.

Kubota MX5200 with LA1065 loader.

My thoughts are to go with a 3/4" valve for the purpose of throttling the speed of loader functions way down when me or the mrs's needs to be in a basket on the forks to reach high things, like gutters or picking fruit from high spots. When we take the basket off the forks and use the tractor normally I can open the flow control way open and not experience any loss of speed. But for the times we're suspended on the end of the forks, I can close the needle valve so that no movements take place at a fast speed.

Am I thinking correct on this? Will a 3/4" hydraulic flow control impede flow noticeably when all the way open? Or will it be like nothing is there? I don't want to do this twice so any experience in these types of things would be appreciated.

 

[ptsg]

You have a couple options.

- First, would be to operate at idle. This will give you the lowest hydraulic flow and therefore speed.

- Second option would be to put a flow control valve in line with the rest of the circuit, before the loader valve but you'll need to dump the extra flow back to the tank/transmission, so it doesn't create heat and so you're not pushing constantly through the relief valve, which again, creates it.

Something like this: 1/2 NPT Hydraulic Flow Control Valve w/Relief Prince RDRS150-16 | Prince Mfg | Brands | www.surpluscenter.com

Not necessarily that one, it's just an example. You'll need to figure out the max flow of the tractor and get one that matches that so you get no restriction, along with the right fitting size.

The line that currently feeds the loader valve would go on the IN port of the flow control valve. The CF (controlled flow) of the flow control valve will feed the loader valve and the EF (Excess flow) needs to be dump back to the transmission, so you would need to Tee it with the tank line of the loader valve.

- Third option, would be to get those inline flow control valves, put one on the line going to the lift cylinders and another one of the line going to the curl cylinders. Get the style that restricts the flow in both directions and you'll only need two of those. Like this, again, just an example. You need to figure out the fitting size and etc. 3/8 NPT 15.5 GPM DYNAMIC JPNV-3/8-NPT Needle Valve | Dynamic | Brands | www.surpluscenter.com

If the first option it's not slow enough, the third would be my go to choice. Much simpler, cheaper and works just as good. Plus you can have different setting for the lift and the curl circuits.

The second one if a bit more complex and expensive but easier to adjust since it's just one small lever and you could even just put a mark in there so you know where to set it every time. This option will also slow down the 3 pt and anything connected to the remote valves.

If you have any questions, feel free to ask. Sometimes my explanations may not be as clear as it should.

 

[MechanicalGuy]

Thanks for the thorough and detailed response.

You have a couple options.

- First, would be to operate at idle. This will give you the lowest hydraulic flow and therefore speed.

- Second option would be to put a flow control valve in line with the rest of the circuit, before the loader valve but you'll need to dump the extra flow back to the tank/transmission, so it doesn't create heat and so you're not pushing constantly through the relief valve, which again, creates it.

Something like this: 1/2 NPT Hydraulic Flow Control Valve w/Relief Prince RDRS150-16 | Prince Mfg | Brands | www.surpluscenter.com

Not necessarily that one, it's just an example. You'll need to figure out the max flow of the tractor and get one that matches that so you get no restriction, along with the right fitting size.

The line that currently feeds the loader valve would go on the IN port of the flow control valve. The CF (controlled flow) of the flow control valve will feed the loader valve and the EF (Excess flow) needs to be dump back to the transmission, so you would need to Tee it with the tank line of the loader valve.

- Third option, would be to get those inline flow control valves, put one on the line going to the lift cylinders and another one of the line going to the curl cylinders. Get the style that restricts the flow in both directions and you'll only need two of those. Like this, again, just an example. You need to figure out the fitting size and etc. 3/8 NPT 15.5 GPM DYNAMIC JPNV-3/8-NPT Needle Valve | Dynamic | Brands | www.surpluscenter.com

If the first option it's not slow enough, the third would be my go to choice. Much simpler, cheaper and works just as good. Plus you can have different setting for the lift and the curl circuits.

The second one if a bit more complex and expensive but easier to adjust since it's just one small lever and you could even just put a mark in there so you know where to set it every time. This option will also slow down the 3 pt and anything connected to the remote valves.

If you have any questions, feel free to ask. Sometimes my explanations may not be as clear as it should.

Thanks for the thorough and detailed response.

I thought that I'd be able to put a single flow control in the supply to the loader, meter-in, like I've seen on many hydraulic circuits before. I'm trying to think of why this circuit would need a return to tank for extra flow. I obviously don't understand the way these hydraulics on this tractor work if that is required. Is there constant flow going to the loader at all times right now? Does it flow over to a return when no actions are being performed?

The "idle" speed suggestion, or how I have been operating this to date, is looking more attractive by the minute.

 

[oldnslo]

Yes that tractor has a gear pump so when ever pump is turning the oil is flowing somewhere that is why ptsg stated you need a priority flow control for inlet into the loader valve with a relief valve that has excess going directly to tank.

Note: a single valve that is restricting flow into the FEL valve will Not repeat NOT prevent fast lowering or dumping since these will both move via gravity.

To prevent rapid lowering you need a meter out restriction in blind end of the lift cylinders.

To prevent fast dump you need a restriction in the dump cylinder line typically the rod end on most loaders similar to what people do to prevent the floppy bucket problem.