Processor

[Lea]

I知 starting to commission my home made firewood processor,and I am having trouble with the splitter on it.
I seems like it is building too mush presure on the splitting cycle and the drive chain to the hydraulic pump is jumping. Upon closer inspection I noticed both key ways were broke. I知 mean the quarter inch keys on the shaft of the pump and the shaft on the drive. That would tell me too high of pressure, but everything else works good with no problems. My cylinder is 4 with 2 rod. Is it possible that y cylinder is just too small? The pump is a four bank gear pump and the splitter is on its own bank.
Anyone got any ideas?

 

[oldnslo]

Have you checked the relief valve setting on the splitter valve. From your description this would have a separate relief from the other functions.

Note: I couldn稚 view the picture so you may be showing something that answers my question.

 

[Lea]

The relief valve does seem to be working.
But as soon as the splitter stars to build pressure the chain skips, and I know that is going to cost me very quickly
The relief seems to opening around 1500psi

 

[4570Man]

That’s only about 9 tons. Are you sure it’s only 1500 psi? How tight is that chain?

 

[Lea]

The chain is as tight as I dare to tighten it. It doesn’t have a idler on it but one is in the works for it
Is there a possibility that the pump could be turning the wrong way

 

[4570Man]

It would seem that as long as the system is working the pump it’s self isn’t the problem, but I guess it’s possible.

 

[ericm979]

If the chain or sprockets are worn the chain can skip. Also if the sprockets are not in parallel and in plane- chains like to go straight.
Smaller sprockets can handle less torque. The small one may be too small. I think there's formulas for allowable torque for each chain size. Maybe in Machinery Handbook?

 

[muddstopper]

No pictures of broken keyways, but the fact that they are 1/4 in suggests to me you are using small dia shafts, at least on the sprockets. It also looks like you are using a pretty small size chain with a lot of distance between the two sprockets. I would try installing some sort of idler sprocket to take up any slack that occurs when the sprockets come under load (stretch). The longer the distance between the two sprockets, the more likely the chains will stretch and slip. It diesnt take much slack or stretch for a small chain to jump over the sprocket teeth on the smaller sprocket.

 

[Leejohn]

While you are working on it you might want to check the side load on the pump. I used number 50 chain on my splitter

 

[Lea]

The chain and sprockets are new #60 chain.
It almost seems like the pump is fighting against itself
I worked on it for about an hour today and thought maybe the filter is plugged on return line. I’ll check tomorrow and see if it’s plugged. Is this a possible cause?

 

[Lea]

I need to find myself a good hydraulic mechanic. But I’m sure you guys will figure it out.

 

[oldnslo]

It almost seems like the pump is fighting against itself
I worked on it for about an hour today and thought maybe the filter is plugged on return line. I値l check tomorrow and see if it痴 plugged. Is this a possible cause?

I would suspect that the splitting function requires the most HP of the functions so that would be the most stressful time on the chain and sprockets. For the splitter is there just one section of the pump feeding this or are you combining two sections for a hi - lo system? If hi - lo system what are you using to unload the high flow section? If this valve is chattering it could cause the pump to sound like it is fighting itself.

If this is a spin-on style return filter they typically have a built in by-pass that limits the amount of back pressure. Most of these filters will rupture at 250 - 300 PSI so doubtful this would be the cause of your problem.

An under sized valve or return line could increase the back pressure but you should see this on the gauge in the pressure line.

 

[mike48130]

Tee in a pressure gauge at the pump to see what it is really doing. It is possible the pressure relief is sticking. What type of valve is it? Does the the relief use a separate return line or internally returned to the valve ouput?

 

[Lea]

Yes there is one independent function for the splitter cylinder. The filter is a canister style.
Lea

 

[Lea]

The relief uses a separate line and also goes to the filter
Lea

 

[bigdeano]

I suspect the sprocket on the pump is too small. It would take a huge pull on the chain to develop enough torque on the pump with that small a sprocket. You must have a large engine to not stall it with that big a load. That's my best guess anyway.

 

[Lea]

I have a 14 1/2” sprocket turning at 300 rpm on the power side and a 3 3/4” on the pump.

 

[bigdeano]

I have a 14 1/2” sprocket turning at 300 rpm on the power side and a 3 3/4” on the pump.

Ok, I couldn't see the pump sprocket clearly on my little screen. That would seem big enough. Is the engine on rubber mounts? Seems like something must be moving to let the chain come off. I've never had that happen, even with a lot of torque. I'm stumped.

 

[Tractor Seabee]

Oh how I love DIY engineering. I am not an engineer so cannot be of much help. There is not enough info here to even come close to exercising our practical field minds that try to know every thing. What were your original design specifications? What pressure to the cylinder are you trying to obtain. Did you run calculations on the pump and drive output characteristics, PSI, GPM? I hope the malleable pipe fittings observable in the pictures are only on the return to tank and not the pressure lines. XH pipe and steel fittings are a necessity. Early failure is predicted otherwise and could be dangerous with hot oil spraying all over.

I hear ole Rube rolling over in his grave. Don't worry I have been where you are and had to change things I overlooked or did not realize.

Ron

 

[ericm979]

What's the pump's rated rpm?

What's driving the driven sprocket at 300 rpm?

Chains don't have to be tight to not skip. On most chain drive motorcycles the chain has to have a couple inches of play to allow the suspension to move.