Load Sensing Hydraulics

[monkeybusiness]

Hi - I'm having a large ex-military hydraulic winch built up into a 3pl frame with spade legs to go on the front of my tractor, and need to sort a spool block. As well as regular spools the tractor has a power-beyond hydraulic supply that will apparently send a whole world of oil on demand, but this needs a load sensing hydraulic spool valve fitting to control the winch. It also needs 12v solenoid control to allow it to be used with a remote. Does anyone know anything about these valves (ideally where to source for less than a million pounds?!). We are looking at a flow rate of approx 150l/min apparently, and it would be beneficial to have proportional control ideally. Cheers!

[treequip]

You said a bad word. Proportional controll is expensive, way more than a conventional closed/open system. Why do you need proportional cotroll?

 

The power beyond function is normally for intermittent peak demand, using it on a winch where all sorts can go wrong dosent sound like a good idea to me.

[monkeybusiness]

That's the sort of info I need to hear - I know very little about this TBH. I thought that harnessing the max. available flow from the power beyond (it apparently offers far more oil flow than the regular spools) would be the best way to go with a very oil hungry winch. Power beyond is already fitted to my tractor so I have put 2 and 2 together and assumed it would be the best way of getting decent performance from the winch (but this may well equal 5). Perhaps there is only a need for proportional control from the spool itself (for feeding wire back onto the drum etc) and the remote only needs 'binary' control? I assume that this would be a lot more reasonably priced? In terms of the pressures involved, the winch will have a pressure relief valve fitted which should always give before anything breaks (in theory anyway!) so it shouldn't matter if the power beyond does its best to keep up with demand - that's my limited understanding of hydraulics pretty much exhausted though... If I am barking up the wrong tree I need to know now though, before I spend a load of money on this. The other option is to combine 2 spools and send this through a bigger hose, but I believe that the power beyond is still capable of providing a greater flow of oil (I'm happy to be proven wrong though).

[treequip]

OK so its clear we need to do a little benchmarking

 

First thing to find out is what flow the winch would like, it will have a maximum, minimum and an ideal FLOW RATE somewhere between the two.

 

Now we need to know its operating pressure. There should be a plate on the motor with this info.

 

Once you have those, consult the tractor handbook or the interweb to find out how much flow and pressure your fine machine will make.

 

Many modern tractors have tandem pumps so flow might not be an issue, if your machine comes up lacking you may have to fit a compatible PTO pump, often the front PTO (if you have one) is the logical place for this.

 

Less flow will mean a slower winch but as long as the pressure is there the power will also be there.

 

Too much flow is counter productive, you end up labouring the pump, relief valves and boiling the oil

[monkeybusiness]

Yeah - the winch wants around 150l/min and the tractor can apparently deliver upto that via power beyond (it will be more like 80l/min through 2 combined spools). Pressure I need to double check but I can't see it wanting much less than the tractor's 200 bar. This doesn't really concern me too much as it is relatively easy to reduce delivered pressure - it is harder to up the flow without spending dollars! My quandary is whether to spend the money on a spool valve and make use of the tractor's in built high flow pump, or spend money on a pto pump and use the spool valve that came with the winch. I don't know what other applications these spool valves are used in so am unsure where to look for second hand equivalents if the power beyond route potentially works.

[treequip]

Ok so I have had a quick read up on the JD power beyond thing

 

It seems to be nothing more than an enthusiastic name for tandem pumps.

 

You don't really need proportional control for a winch, a simple open centre valve will do

[C.J]

You won't get more output by using 2 of the tractors spool valves.

 

Sounds like the winch will need to be connected to power beyond to get the flow you require.

 

A PTO pump requires a reservoir and 150-200 litres of oil so is not a cheap option.It may also prevent you from attaching what you want to the rear e.g 3 point linkage.

[monkeybusiness]

I'm not sure that it would - there is some sort of pilot control line that 'Signals' the pump to deliver oil. How would an open centre valve incorporate this? There are no manual controls on the tractor to activate this particular spool, just 3 (1 large supply, 1 large drain and 1 small pilot control) hydraulic fittings on the back.

[treequip]

You won't get more output by using 2 of the tractors spool valves.

 

Sounds like the winch will need to be connected to power beyond to get the flow you require.

 

A PTO pump requires a reservoir and 150-200 litres of oil so is not a cheap option.It may also prevent you from attaching what you want to the rear e.g 3 point linkage.

 

There is one in the tractor back end you can make use of:thumbup1:

[C.J]

There is one in the tractor back end you can make use of:thumbup1:

 

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