Firewood Processor

[shanerr]

Need some assistance on the hydraulics for a firewood process that i am building. I have a 23hp kohler and 15 gpm hydraulic motor to run the chainsaw. I am not sure what size pump i need. The 23hp runs 3600 rpms and max throttle. Any help on the pump is a appreciated. Hydraulics is not my strong suit.

 

[Tractor Seabee]

I am no expert. Check out the guys at Surplus Center. There is an on-line catalog you can download. Their Tech depart is really good. Seems like most Hyd pumps and motors work at a lot lower RPM that that gas engine, probably need a gear reduction box or a pulley arrangement. Remember hyd pumps are positive displacement so you need a relief valve back to the sump set for the optimum pressure of your motor and line accessories. JJ our forum hyd expert always recommends SC in his posts. He will probably jump in here.

Ron

 

[shanerr]

Thanks Ron i reviewed the web site. I will be calling them tomorrow.

 

[johndeerkiwi]

I can assist, but need to know a bit more information.....is the chainsaw is the only item absorbing power from your engine during the cut cycle, and if it is not, what else are you using? ie are you going to have a hydraulic ram lowering the saw, or a manual system? Will you use the same pump to work the splitting ram by taking turns with the chainsaw?(with 23 horsepower, that is probably the best option). Are you talking American gallons or imperial? (I assume American?)

The maximum recommended horsepower for a .404 chain is 50 h.p, but 23h.p is still alot faster than your faithful huskey, or whatever!! A 23 hp saw (.404pitch) at recommended revs will cut a 9"dia log in just over 1 second (80 square inches a second)

Achieving the recommended chain speed, also depends on the sprocket. The minimum recommended .404 chain speed is 15 m/sec or 3,000 ft/min, and the maximum, (and recommended) speed is 40 m/sec or 8,000 ft/min.
The largests commonly available .404 sprocket, in New Zealand at least, is a #14 tooth, and to achieve the recommended speed (40m/sec or 8,000 ft/min, you need 8,352 rpm on the saw shaft.
This is too fast for a standard hydraulic motor, although you can buy bent axis motors that are purpose built for this rpm (parker f-11 & f-12 series), but they are quite expensive. So some use a standard gear pump at maximum revs, and put up with a slightly slower cut, or you can use a chain drive to the saw shaft to speed the saw shaft up, such as a small duplex chain.
All motors have a flow per revolution so you can easily do the maths to work out how fast the motor will go with a certain flow.
However, there there are some variables to work through, such as do you wish to direct drive the pump off the motor?

 

[shanerr]

the chainsaw and a small cylinder to use to clamp down on the log while cutting will be the only motor/cylinder i will be powering off the 23hp motor. I am setting up the saw to operate manually. I have a separate motor 18hp to power a 28gpm 2 stage to run a 5x36 cylinder to split the wood.

 

[J_J]

Your 23 HP engine can pump about 11 GPM at 3000 psi. Will pump 13.5 GPM at 2500 psi.

 

[shanerr]

Thanks J_J If i figure right i should get at least 15gpm at 2000psi correct?

 

[J_J]

I got 16.5 GPM at 2000 psi using the 23 HP.

To get 15 GPM from a 3600 rpm engine, you have to have a 1 cu in displacement pump.

So to pump those GPM's, 15 , at 3000, you need

You select a pump based on the GPM/cu in displacement, at a certain rpm.

Any pressure developed from the pump is based on the load which will produce pressure, and with a potential to go as high as pump pressure at say 3000 psi.

You can limit the pressure by adjusting the relief valve to say 2000 psi.

At that pressure, you will not be using the 23 HP, maybe 21 HP

The volume and pressure potential will be based on the pump you have.

Do you have the pump now, and if so, I can tell you the HP required to turn the pump at a certain pressure ..

This pump is .98 cu in, and can develop pressure up to 2900 continious, and a 3000 rpm limit


SPECIFICATIONS
0.98 cu in dia
2900 PSI cont
3625 PSI int
3000 RPM max
5.7 GPM @ 1500 RPM
11.9 GPM @ 3000 RPM

 

[muddstopper]

I will point you to this thread on the forestry forum, I hope this is allowed, if not I guess the moderators will delete the link. http://www.forestryforum.com/board/index.php/topic,61961.0.html

Jdeerekiwi has given some good info already, I would give CRD metalworks a call and talk to their engineers. They will give you some good advise and can sell you the parts you need, including saw motor, sprockets, bars and chains.

A word of warning about purchaseing your saw motor, I havent found a decent motor for this purpose on the Surplus center site, even tho they do sell a lot of motors for this purpose. Will they work, yes, but do you want something that will work and eventually get the job done?, or do the work in a safe and efficient manner. Just because it will do the job, doesnt mean its the right tool for the job. The parker f11 and f12 motors will do the job very well, but you will find that a new motor will cost you several thousand $$$. The cheap small high speed motors, like are found on the surplus center site, will work, but dont have the power you need to be efficient. A compromise has to be made based on how much you can justify spending, and how much time you are willing to dedicate to getting the job done. This will most likely mean using a larger hydraulic gear motor with more torque and less speed than what you really want. Options to increase the speed of the saw chain are to use a high torque, low speed gear pump and drive the saw thru a jackshaft and pulley system. Which is what i am planning with my processor build. This isnt as simple as just mounting a shaft in some pillowblock type bearing. and throwing on different size pullies. Most pillow block bearing are only designed to run a few thousand rpms. Special high speed bearings that will withstand the 6-8000rpm desired speed are pretty costly. They also require a better lubrication system than just a few pumps of grease from a grease gun.

Another word on sprocket size. You can get all kinds of different size sprockets with different numbers of teeth or pins for pulling the saw chain. Size your sprocket to your saw bar. To large a sprocket to try to increase the chain speed will lift the chain out of the rails of the bar and cause excessive wear on your chain and sprocket, to small a sprocket will put unnecessary wear on the bar and chain.

 

[wdchyd]

Need some assistance on the hydraulics for a firewood process that i am building. I have a 23hp kohler and 15 gpm hydraulic motor to run the chainsaw. I am not sure what size pump i need. The 23hp runs 3600 rpms and max throttle. Any help on the pump is a appreciated. Hydraulics is not my strong suit.

Depending on how many functions you wish to do at the same time, you may consider getting a pump with multiple sections to allow hyd circuits to act independ of each other.....I've seen many firewood processors with 2, 3 & 4 sections