Firewood processor help

[jonix]

Hi,

"Originally Posted by jonix"

"Sorry to use your post to try to solve my problem , but I'm desperately in need of help. I am in the final phase of a firewood processor ( 3D images ) , and the first tests did not go well. The two 50 lts/min (13.2GPM) and 66 lts/min (17.4 GPM) gear pumps exceed 5000 PSI (!!!!) and still not achieve the 10 cm (3.9" that should develop 30.4 tons @ 5000 PSI) (how do you get this result?!) diameter piston to split eucalyptus with a 400 mm (15.75") diameter into my 8 edges knife ..can anyone help me with this? (a picture of the splitter cylinder and wedge would be helpful) (in the end i post a youtube link to a walk around video, and a jpg with the hydraulic circuit, the only thing i donｴt know is the valve types that iｴve got there)

And why the F11-005 PARKER (.305 CI / revolution) motor with 34 Lts/min (8.98 GPM) dedicated pump can not get a decent cut at 150 bar (2,175 PSI)? ( a 3/8 pitch chain with a 7 teeth sprocket and a set of pulleys to double speed).. (Saw motor should run at 7200 RPM with the given information developing 100 in/lb of torque and 5.7 HP. Chain should run at 3150 ft/min)

The system has a 18 KW (24 Hp) electric three phase motor with 4 pumps (2 for splitting, 1 for the saw and saw piston, and 1 for log conveyor, log feeder, clamp, log lenght stopper, etc...) what is wrong with this? something has to be wrong... (Need information about how the two pumps are used for splitting)

I can get you much more information and a video of what is happen (all the machine is near to break and still not splitting the wood!!!) if you need/want to see that...

thanks in advance..and i hope anyone helps me, because here in portugal the season is about to begin, and i have no firewood drying..."


I made notes in red. Changed units for those of us not used to metric (thanks, my drawing as already almost converted units). I would say that we really need information about how the two pumps are used to split. We need pictures of the wedge to see how the log will spread out as it is split. Is the wood green or is it dried out? I read that eucalyptus is more difficult to split when dry. (Yes, dry eucaliptus is much more difficult to split, even so i think it should be splitting easly...)

Off hand I would think the splitter would work at 30 tons but (i think i was tell that at 3000 psi it would be working with 40 Tons) it all might depend on the wedge design (yes, the wedge is not totally staggered [thanks SpringHollow], you can see it in the video). Also if there is anything binding (what is binding? canｴt find a translated word for portuguese) in the splitter travel (i donｴt think so, it is only bending when the logs stop because is not being splitted).
The saw seems a bit slow to me (I made an excel sheet about this calculations, but our results arenｴt the same - i can say i trust more in yours . You have decent torque but I would think you'd want your chain speed to be around 5000 ft/min. It could be as simple as changing to an 11 tooth sprocket if one is available (yes, iｴm already waiting for one with 12 tooth).

My previous comments still stand, I would gather additional information and start a new thread for this in the hydraulics or build it yourself section. Feel free to post a link to it here if you wish (thanks again, i would do that).


Youtube video walk around (sorry, i wasnｴt able to film the processor at working, i will try to do it soon)

https://www.youtube.com/watch?v=qFU2Qhwh5Ak


and hydraulic circuit (i think it is all in there)...


thanks again for your help, and hope i could find what is wrong with it..

 

[ptsg]

Hi Jonix, binding means "roçar" or in this case " se existe alguma prisão no rachador" in portuguese. You have a really nice firewood processor! With my homemade splitter, I can split eucalyptus like the one you have in the video with something like 100/120 bar and a 80mm bore cylinder.

 

[J_J]

6 in bore cyl at 3000 psi should have a cyl push force of 84,823 lbs, or 42 tons.

You shoulds have no trouble splitting anything

Install a hyd pressure gauge in the log splitter IN port and tell me the pressure you see when stalling.

Did you ever check or set the log splitter relief?

If you run all pumps at the same time, you would need 91 HP .

25 HP can pump about 12.85 GPM at 3000 psi

With different loads on the pumps, it will be hard to compute the actual HP.

You might get by with running one or two functions at the same time.

You say that your pumps have 7.5 cu in total displacement, and if your motor turns at 1470 rpm it would pump 47.73 GPM's

However to pump 47.73 GPM's, it would need about 91 HP.

Your GPM figures total up to 37.5 GPM, but your pump displacement total up to 7.5 cu in. Which is correct.

 

[jonix]

Thanks PTSG! and no, i think nothing is binding there...

JJ, all i know about hydraulic i learn from google in the past month, so you can guess i´m not a pro

I forgot to tell you one thing, i think it is related with 91 Hp needed..when the splitter stop because it has no force, the electric motor wants to turn off, so we have to stop pushing it...i think the problem might be here..what is happening when we put 25 HP, 2 pumps at 1470 rpm with 24,2 GPM and 4,7 cubic inches displacement to a cylinder..if you say that 25hp only can pump about 12.85 GPM at 3000 psi, i think my pumps are getting to 5000 psi when splitter is stalling (stalling means stopping, i am right?), but my cylinder do not receive that..

"Did you ever check or set the log splitter relief?" - i don´t know what this is, i´m gonna try to figure it out as soon as i can...
"Install a hyd pressure gauge in the log splitter IN port and tell me the pressure you see when stalling" - i don´t have one, i will try to resolve that..

I am returning from shop, and we found some bend steel in the back of the splitter cylinder..i guess it bend on friday tests..later i post a pic..i'm thinking.. if the steel bend, why the wood don´t splitt..?!?!?

 

[SpringHollow]

You have two pumps driving the splitting cylinder with different maximum pressures and flows? Could be one pump fights the other pump because they have different flow rates and pressures? If you really have two pumps feeding the splitter, I would just run it with one initially. That would only affect the cycle time.

Ken

 

[ptsg]

You have two pumps driving the splitting cylinder with different maximum pressures and flows? Could be one pump fights the other pump because they have different flow rates and pressures? If you really have two pumps feeding the splitter, I would just run it with one initially. That would only affect the cycle time.

Ken

Yes, I agree with this. If those two pumps doesn't have check valves, then it might be the problem.

 

[jonix]

Yes, that is correct..i have two pumps with different displacements and flow rates feeding the splitter..i think they have check valves..and yes, i think they are rated for diferent pressures too..i was told by the hydraulic circuit manufacter that one pump is for oil flow speed and another is for splitting power (?!?!?)..

well, i went to the shop to see if my guys have any developments..and they have..they are already replacing the cylinder for a new one with a 6,3'' inside camera, and 7,87'' outside..the piston (i think you call it rod) will be the same (3,5'')..they said with this new one cylinder we should achieve 55 Ton of splitting force..

I told them..i don´t know if the problem is in the cylinder size..

 

[Wild Bill the 2nd]

The two 50 lts/min (13.2GPM) and 66 lts/min (17.4 GPM) gear pumps exceed 5000 PSI (!!!!) and still not achieve the 10 cm diameter piston (3.9" that should develop 30.4 tons @ 5000 PSI) (how do you get this result?!)

Off hand I would think the splitter would work at 30 tons but (i think i was tell that at 3000 psi it would be working with 40 Tons) it all might depend on the wedge design (yes, the wedge is not totally staggered [thanks SpringHollow], you can see it in the video).

Jonix, I was under the impression that the splitter piston diameter was 10 CM which would be 3.94" It appears to be much larger than that from the video. So you may be achieving 40 tons at 3000 PSI

And why the F11-005 PARKER (.305 CI / revolution) motor with 34 Lts/min (8.98 GPM) dedicated pump can not get a decent cut at 150 bar (2,175 PSI)? ( a 3/8 pitch chain with a 7 teeth sprocket and a set of pulleys to double speed).. (Saw motor should run at 7200 RPM with the given information developing 100 in/lb of torque and 5.7 HP. Chain should run at 3150 ft/min)

The saw seems a bit slow to me (I made an excel sheet about this calculations, but our results arenｴt the same - i can say i trust more in yours . You have decent torque but I would think you'd want your chain speed to be around 5000 ft/min. It could be as simple as changing to an 11 tooth sprocket if one is available (yes, iｴm already waiting for one with 12 tooth).

My calculations here were flat out wrong. I must have forgotten to change a parameter in my spreadsheet or my google spreadsheet did not update calculations after I made changes. Sorry.
5cc (.305 ci) displacement at 34 Lts/min (8.98 GPM) should yield 6800 RPM at the motor. So with 150 bar (2175 PSI) at the motor you would give you 11.9 N/m (105 in/lb) of torque and 11.4 HP
You say you have a set of pulleys to double the speed of the motor. That would give you 13600 RPM but cut the torque and power in half. Disregard the sprocket recommendations. I obviously should have waited to reply when I was more awake...
At 13600 RPM with a 7 tooth sprocket with 3/8" chain would travel 5950 ft/min which is reasonable.

The data you have in your attached document matches up pretty well to this. Differences due to rounding.

One other question about your two pumps. Did the person that specked out the pumps intend on having one higher pressure, lower flow pump to extend the cylinder and then another higher volume lower pressure pump to retract the cylinder quickly?

 

[J_J]

I don't believe you have any idea of the pressure developed by maxing out the cyl.

Eve then if you do see some pressure, what is the valve recommended relief setting?

Who developed this idea of the two pumps for a single cyl when there are pumps available. with the displacement you need.

I am not even sure you can get a valve or cyl that will take that pressure.

The cyl and pump manufacturer, have they supplied parts to other log splitters?

How did you start this process of putting the parts together.

Did you know how much tonnage needed to get the job done.

Did you start with the electric motor and that becomes your limiting factor as to the displacement of all the pumps.

Has anybody ever built a log splitter with the capability of 84 tons?

Something is wrong with this total process.

Just what are your limiting factors. Are you stuck with the parts you have.

What is the pressure ratings on your cyl, and valves.

What is the name and model number of the log splitter valve or is it even a log splitter valve.

Your F-11 saw needs about 15 GPM minimum to run and if it can develop 6000 psi, you need about 29 HP just to run the saw.

If the log splitter valve is limited to about 3000 psi, due to the relief valve, then you only need about 15 HP

The saw will run at any GPM, but the speed of the saw motor is relative to the GPM.

You can increase the speed of the saw, but the torque will decrease.

Apparently, you are not using a standard log splitting valve with auto return.

I see all solenoid valves, but where is the relief valve?

Early on you said you did not know what that was, but it is of great importance as it will protect the pump from excessive pressure.

Every hyd system should have a relief valve, and each circuit should have one. .

Your two p mps at 24.2 GPM and 3000 psi, would require about 47HP.

I think someone messed up on total HP required.

Your cyl and valves have a psi rating, what is it?

The cyl will take what ever GPM is fed into it and develop the pressure based on the load.

Motor stalling will be based on the total load on the pump, which is driven by the electric motor.

 

[jonix]

The data you have in your attached document matches up pretty well to this. Differences due to rounding

Yes Bill, think we both have about the same formulas..i´m waiting for a 12 tooth sprocket because my F11-005 is going to be replaced for a f11-010, and it should give me double power, but half rpm, since i have the same oil flow for the new f11-010 (witch can work at 25 gal/min)..think the set of pulleys will stay as they are, and with the 12 tooth sprocket i should get 22 N.m of torque, 21 HP, 5000 ft/min on chain travel and 6500 rpm (all this at 2200 psi)

I think both pumps were rated to work together in both retract and extend cylinder. But i was told that, yes, one is for higher volume, low pressure, and another reinforced for higher pressure, but lower oil flow..well..thats all i know..anyway, in the shop the splitter cylinder is already being replaced (i could not get in on time ..it should take one or two days to make the new one and place it in the processor..