Hydraulic ram's - adjustable relief valve, accumulator, or something else?

[PuG]

Afternoon,

I'm in the process of building a single disc drill. The leg moves up and down to follow the ground contour and I was hoping to have that controlled by a single acting hydraulic ram with a variable pressure to dictate the force being applied depending on the soil conditions.

I don't want to use springs, ideally.

My original idea was to have an adjustable pressure relief valve (like found on my JD 575 baler rear door) which would have a pipe coming from the tractor spool and a return that would be pumping in a loop to maintain downward pressure defined by the relief valve. Then from the valve to the ram(s).

So when the ground fall's away from the leg the ram extends maintaining the downward pressure, when it goes in the other direction the relief valve kicks in and lets the ram shorten accordingly.

I've looked on the flow fit website and I'm just lost, I have give them a ring but the technical chap is pretty busy.

So I'm posting for advice! does anything actually exist that does what I want. I don't know anything about accumulators either, and whether they are better suited for the job.

Going to be six single acting rams in total. I had planned just to daisy chain them together back to the relief valve setup.

Cheers, James

 

[towbar]

Overrun plough uses hydraulic pressure for stone release. I think it uses the tractor spool to charge an accumulator.

 

[PuG]

I don't think an accumulator is really necessarily - spent last hour or so searching more and JD750 drill uses a simple relief valve and the hydraulics are set on constant. Something like:

hydraulic relief valveRELIEF VALVE DIR ACTING (VMD8004B3) - HTL Website - HTL (Formerly BYPY)

mtc hydraulic valves

www.htluk.co.uk

https://sklep.dzwigi.net.pl/upload/original/Sklep%20zdjecia/zawory/vmd.pdf

Looking at about 500 psi so it looks right for the job and high through put on L/p min, so perhaps I've answered my own question?

 

[Flat 10]

@Mr Happy might help....

 

[cosmagedon]

Personally I think I would go down the accumulator route so your not having to run a spool valve all the time.

I presume you will be running a hydraulic fan? You could always tee into this line like a Mzuri does and pressure the legs that way. Although this does sap a hell of a lot of Hydraulic flow.

 

[PuG]

No hydraulic fan, I'm building electric seed meters similar to the brushed ones and individual boxes on each leg. I presume an accumulator could be easily attached but I've struggling to find a good website that stock ones suitable for agri and show prices... Bladder or Diaphragm?

 

[Mr Happy]

@PuG have you been in contact with Hydokit. There headquaters are on France and i find they very helpful.

 

[Bloders]

if you have a hydraulic relief valve, would it generate a lot of heat?

 

[Bob lincs]

We have just built a single disc drill with hyd ram to pressure each disc . I have used double acting rams all linked with an accumulator in the system , I aloso have a pressure gauge and a tap so I just pressure up to the desired pressure and then turn off the tap . The coulters follow the ground really well using the accumulator to float up and down .

 

[towbar]

We have just built a single disc drill with hyd ram to pressure each disc . I have used double acting rams all linked with an accumulator in the system , I aloso have a pressure gauge and a tap so I just pressure up to the desired pressure and then turn off the tap . The coulters follow the ground really well using the accumulator to float up and down .

Lovely job but Why did you use double acting rams though? Do you keep pressure on both sides of ram?

 

[Bob lincs]

The main reason for using double acting rams is so the coulters don’t droop down when I pick up at the ends , also they don’t swing out when going up the road .

 

[Andrew]

We have an auto reset Sumo subsoiler which has 5 rams connected to 4 accumulators and a tap.
Personally I’d think this was a better setup than a spool running constantly which will sap some horsepower.

 

[PuG]

We have just built a single disc drill with hyd ram to pressure each disc . I have used double acting rams all linked with an accumulator in the system , I aloso have a pressure gauge and a tap so I just pressure up to the desired pressure and then turn off the tap . The coulters follow the ground really well using the accumulator to float up and down .View attachment 831485

Look excellent! and very similar to what we're after. Just waiting to start cutting steel. The only differences I think is our disc is a compound angle, 21 degrees, 7 degrees so it undercuts and I'm going to try a depth wheel at the rear of the assembly which also squeeze the furrow closed.

Out of interest, do you have the part numbers and where you bought the accumulator / pressure valve/gauge from?

Would it be cheeky to ask for some pictures closer up if you have five minutes?

Really impressed.

 

[Bob lincs]

Look excellent! and very similar to what we're after. Just waiting to start cutting steel. The only differences I think is our disc is a compound angle, 21 degrees, 7 degrees so it undercuts and I'm going to try a depth wheel at the rear of the assembly which also squeeze the furrow closed.

Out of interest, do you have the part numbers and where you bought the accumulator / pressure valve/gauge from?

Would it be cheeky to ask for some pictures closer up if you have five minutes?

Really impressed.

All of my hydraulic components came off a scrapped weaving drill , I will have look and see if there are any part numbers on the accumulator . What would you like pics of ?

 

[PuG]

Couple of pictures of the leg themselves either side would be great (just to see how you've done it compared to ours if that's okay!) and perhaps a picture of the hydraulic components. Only if you have time. Having seen yours I might revert our leg angle, originally it was 22 degrees downwards from the pivot to the disc, but to make it easier for cutting the steel on our CNC made it level from the frame to the depth wheel but it only leaves 130mm ground clearance on the main box steel which I don't think is enough.

Just waiting on our hubs to come for turning in the lathe to try and mount the JD disc.

 

[beefsheeparable]

Got something similar in mind, how did it go in the end @PuG? Ta