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..

 

[jonix]

I don't believe you have any idea of the pressure developed by maxing out the cyl.i told you, i´m no pro

Eve then if you do see some pressure, what is the valve recommended relief setting? yes, i saw 350 bar of pressure on those pressure gauges, but the recomended relief pressure is about 3000 psi

Who developed this idea of the two pumps for a single cyl when there are pumps available. with the displacement you need.this project began with the purchase of all hydraulic circuit to a hydraulic stuff company near by, they have an engineer to do all the calculations, and it was spendt about 6000€ on this..and i agree with, why so many pumps, if you don´t have the power to run it all at the same time..think the engineer messed all up

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? think not

How did you start this process of putting the parts together.first by drawing it, second hydraulic circuit, and then steel

Did you know how much tonnage needed to get the job done.well, god question, think 40 tons should be more than enought for eucalyptus

Did you start with the electric motor and that becomes your limiting factor as to the displacement of all the pumps.gas here in portugal is not cheap, and did´t know NOTHING (still about firewood processor oil flow and power about a year ago

Has anybody ever built a log splitter with the capability of 84 tons?i think there are splitters in the market with more than that..but..

Something is wrong with this total process. don´t tell

Just what are your limiting factors. Are you stuck with the parts you have.yes, now i´m stuck with the parts.. I managed the company swapped the F11-005 to a F11-010 and the pump that feeds this motor..inicially, the engineer calculation was a 3 Gal/min pump for the F11-005 (that can work with 14 gal) he choosen, and one more valve for the saw cylinder..he put both on the same circuit..engineers..think that I can not ask the company to change anything else...relational problems already exist..

What is the pressure ratings on your cyl, and valves. don´t know...i will try to get this

What is the name and model number of the log splitter valve or is it even a log splitter valve.i think it is not a splitter valve, wonder if the engineer knows how firewood is made...i can get these number tomorrow..

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.yes, think this part will be solved with the F11-010..




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

I see all solenoid valves, but where is the relief valve? do you Know the tecnichal word for "relief valve" in Portuguese?

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.

thank you J.J, but as you see, there are knowledge limitions here, and post almost a year, when we did some primary testing, the result was this..

 

[ptsg]

Relief valve means "Válvula de pressão", I'm from Portugal too

I think that they did a two stage pump with too separate pumps and a separate valve, instead of a regular 2 stage pump like it's usually in log splitters.

 

[J_J]

Is the GPM correct or the cu in displacement correct.

What you could do is to run one function at a time, to have enough HP to get things done.

The GPM of a pump is rated at max rpm, and if you run it at half speed, the GPM will be halved.

If your cyl is 6 in bore and 3.5 rod, and pump pressure was 3000 psi, your cyl could develop about 84,832 lbs, or 42 ton. Retract tonage will be less.

Your speed will be determined by the GPM into the cyl.

You could also build a lockout function so only one valve has power at a time, or whatever will allow you to maintain HP at all times. .

 

[jonix]

Relief valve means "Válvula de pressão", I'm from Portugal too

I think that they did a two stage pump with too separate pumps and a separate valve, instead of a regular 2 stage pump like it's usually in log splitters.

yes, i know..the relief valve question was not really for J.J

And what is the diference between a regular 2 stage pump, and 2 separate pumps?

 

[jonix]

So J.J, this new one cylinder with a 6,3'' inside camera, and 7,87'' outside with the same 3,5'' rod will develop how much tonnes of power? how do you do the math?

I have a question, maybe you can answer it: if my two pumps at 24.2 GPM and 3000 psi, would require about 47HP, and i only have 25Hp, what is happening in the hyd system?..guessing, since i saw it working with this setup: with 25HP i can pump 25 GPM (rounding), but only at half of pressure, since i have half of power..or i can only pump half of GPM and the same pressure?..can you post the formulas for this calculations, so i could understand it ...i think this part of the math is important too..guessing..

 

[J_J]

Go here. Surplus Center

Select technicall help.

On left side, select hydraulic calculators.

Hydraulics
Calculators
Cylinder Force & Speed
Gear Pump Replacement
Pump Disp., HP, GPM & RPM
Motor Speed, Torque & HP
Cylinder Definitions
Cylinder Ends
Hose Sizing
Pumps & Motors

Select pump Disp

Plug in some numbers and there you go.

Whatever you put together, if the hyd are not working under a load, you do not need much HP.

You will have max flow based on the pumps max rpm.

As soon as the hyd sees a load, pressure develops.

The HP required to support that load, pressure, etv, will be met and things work OK to a point.

If you add more load than the system has HP, you are at your max, and after that, you may stall the system.

Did that engineer do all the math for you or is that your doings, and did you just ordered the parts based on his recommendation.

I say again, you can use some of what you have, but can not use all pumps to full advantage at the same time.

What you try to do in a hyd system is to design for min operation, and then add some extra for true operation. Design for maximum potential. .

If you run out of HP, the system will slow down, quit or burn up the motor.

It would be analogous to you pushing a bolder on level ground and then you try and push same bolder up a hill. Need more power.

Had you put your design on TBN before, someone could have saved you a lot of headaches.

However one has to know the true details, such as HP, cu in, size, etc.

 

[jonix]

very nice this surplus center..thanks!

I think i understand now..as the system develops pressure, at the design flow rate (25GPM), it will be needed much more HP..since i only have 25HP, the electric motor wants to shut down.. i should have, for example, a 20GPM pump with low pressure, and a switch for a 5GPM pump rated with high pressure, to do get the job done..think this is the 2 stage logsplitter pump that ptsg talk about..:thumbsup:

..all the math was done by the engineer..we only said the purpose of each machine moving part, and if it will be moved by a hyd motor or a cylinder..

..well..i think i solve my problem by getting one of those 2 stage pumps..but they already doing a bigger cylinder for the splitting part..at the shop there is not much patience to wait and do things well..

 

[oldnslo]

jonix,
here are some formula based on the metric system.

For reference:
The saw pump of 34 lpm @ 150 Bar requires 10 kW power at 85% efficient

Splitter pumps:
50 lpm @ 250 Bar requires 24.5 kW power at 85% efficient (I used 250 bar since a lot of gear pumps are rated to 250 Bar)
this does not take into consideration any other loads on the motor of which there will be.

 

[J_J]

This is the largest 2 stage pump that Surplus sells, at 28 GPM. Min of 16 HP engine

28 GPM DYNAMIC 2-STAGE PUMP

You need 13.6 HP to pump 7 GPM at 3000 psi
------------------------------28 GPM at 800 psi

How are you going to power a two stage pump with pumps piggybacked to each other?

You can adjust the crossover psi between 400 and 900 psi/

 

[ptsg]

So you are saying that with two independent pumps, one with high GPM and low pressure and other with low GPM and high pressure, with the proper valve to swap between pumps, can´t do the same as a 2 stage pump? Because it is probably what jonix has in his processor.

The problem that jonix is experiencing must be the relief valves and unloading pressure not set right, it probably cause the system to produce excessive pressure when it shouldn't.

For what I can see, this processor is made to work automatic, that's why they use solenoid valves and not a log splitter valve.