My firewood processor build

[fordf150]

Conveyor should only need about 1400 psi @ 6gpm. Use a priority valve to control the flow.

My processor has the saw, clamp, conveyor on one pump. Circuit is as follows....

Pump to a pressure control valve (pressure set to 1400psi) then to a priority valve where the conveyor gets dedicated 7gpm and remainder of flow goes to the the clamp/saw. Conveyor then has a flow control to regulate speed. The excess flow from the priority valve goes a 2 spool valve. One has a needle valve to control flow so that the saw control can be pulled instead of feathered. Cylinders for the saw and clamp at 1 1/2". 1400psi works good and there is roughly 1gpm flow for the 2 cylinders. Need to up that just a bit.... I would like to install a new priority valve that is 2gpm to the clamp/saw...Remainder to the conveyor

 

[muddstopper]

I'll admit, I havent even looked at the math to figure out the flows needed for the saw and clamp cylinders. Since I planned on using the same pump that controls my knuckle boom, I figured I would need to reduce flow to the saw and clamps cylinders anyways. The 6gpm for the conveyor is close to what I was guessing at for my conveyor, again I havent done the math, I have the flow I have and it should be more than enough to supply this circuit. Again, just sort of took for granted I would have to do a little flow regulating.

The way I plan on connecting the valves for the Out feed conveyor, In feed conveyor, saw cyl and clamp cyl, was to use the power beyond off the loader valve bank. I cant seeing the loader working at the same time as everything else. If i put a diverter valve after the loader valvee and before the other stack valve, I should be able to run the out feed conveyor continuous without any problems. Now, one thing about my two sets of stack valves is that each spool has its own reliefs. As long as the main relief is set for system pressure, I should be able to adjust pressures for each operation independant of what the other spools are set to. I still think I will have to use a flow control and maybe also a pressure reducing valve for the saw bar cyl. Not sure the reliefs on the control valve will go down low enough or be accurate enough at those low pressures.

My saw simply has to be on a separate valve than all the other functions. Oil flow is just to great for any of the stack valves I already have. I do plan on mounting the saw valve right next to the stack valve and seeing if I cant make some sort of joystick so that I can operate the saw clamp and bar cylinder, as well as the saw motor with just one lever. splitting valve is air operated as well as lever operated, I'll use a air foot pedal to control that valve.

Good information to know that 2gpm for bar and clamp cyl and 1400psi for conveyors, that gives me a real good starting point for fine tuning my system. I can divide my 14gpm pump flow in half and still have more than enough for everything to work off of.

 

[fordf150]

Cylinders sizes, travel, and mounting point will all effect your pressure and flow. No clue what my motor is for the conveyor. I bought the cheapest new motor I could find that the math worked out on for 5-6gpm flow. Got lucky and the motor has plenty of torque/room for what I'm doing.

Cylinders for the clamp and saw are 1 1/2" with 1" rods. 14" travel. Heim joint ends IIRC they were only $69 each

 

[muddstopper]

I have the motors for the conveyors laying on a shelf. I will have to look up the numbers before I know what I got. One motor is off my old hydroseeder agitation shaft. I think the pump was 4gpm with pressure around 1100psi. That motor is a stator rotor I bought off ebay several years ago. The other motor for the other conveyor I can look actual schematics up once I get back on the job. Pretty sure its low flow high torque motor. Might be a tad bigger than the stator rotor motor off the hydroseeder. Pretty sure either motor will have enough power to run the conveyors. I also have gear boxes for both conveyors as they where ran off of electric motors. I havent checked the ratios of the gear boxes,. Conveyors are belted and conveyor rollers are about 12" dia so every turn is going to be about 3ft of travel.

Getting back to the saw and clamp cyl, I will have a air compressor to provide air for my splitter valve. I could use an air cyl to move the sawbar. I dont want to open that can of worms unless staying with hydraulics get to costly.

 

[muddstopper]

Looked up the specs for the Valby rotator. max 3000psi. I had not planned on that much pressure, Probably start at around 2000psi and work from there. This setting is important because fluid for the second valve bank will be passing thru KB valves first. Pressure setting there will dictate available pressure down stream for next set of valves. Each spool in both sets of stacked valves have individual reliefs, but any relief that is set over the relief settings for the first valve set will cause fluid to pass thru the main relief for that valve. Basicly, each spool of the second valve set will be protected by three different reliefs, Main relief of first set of valves, Main relief of second set of valves and individual relief for each spool. A little redundant, but the reliefs are already there .

 

[muddstopper]

Thought I might get a few more responses about the hydraulic circuits. I think I begrudgingly have figured out how to make the clamp cyl and saw bar cyl work. Not only do I plan on using two valves, I think I will be best off using two completely different methods. My processor will have a on board air compressor. I need it to use the air shift on the large splitter control valve. Since the saw bar needs to move slowly and with little force. I think air will be the simplest, easiest method to control speed and force. With a meter in and meter out flow arrangement. I should be able to control the speed of the saw cyl and also vary the speed between the different directions, up/down. Air pressure regulators are very cheap, much cheaper than trying to buy hydraulic valves. Air cylinder should be cheaper than hydraulic cyls as well, altho I havent checked the prices yet.

 

[fordf150]

I doubt air will work. On small wood(under 10") I run my saw wide open... 2gpm 1400psi.

I would look at sequence valves for the hydraulics to control the clamp and saw with one valve

 

[muddstopper]

Why do you think air wont work. I also have to ask what are you calling pressure control valves. There are pressure reducing valves and there are pressure relief valves. Most hydraulic operation usually do have some sort of relief to prevent pressure buildup. Relief valves are normally closed valves. No oil passes thru the valve. When pressure builds the relief opens and dumps oil. With a pressure reducing valve, the valve is normally opened with oil flowing straight thru the valve. As pressure builds the valve closes and lets fluid go to tank. Oil running over the relief will create heat as it is always under pressure. Oil dumping over a reducing valve is minimal flow and pressure and doesnt create as much heat.

 

[fordf150]

Volume, pressure just won't be great enough. To get enough pressure on the saw bar with only 125psi of air pressure your going to need a 3" (just randomly picked this number) cylinder and with the larger cylinder I think you will start seeing volume problems.

I'm purely guessing though because I have no experience with air cylinders and limited hydraulic experience.

Only time you really see air cylinders is in manufacturing. They are usually small diameter and fairly short stroked but are used because they are fast acting.

 

[muddstopper]

I understand what you are saying about air cyls. They do have a tendency to slam one way or the other. That is where you need to use flow controls on both the in and out ends of a cyl. Using a flow controls with a check valve bypass will work the same way on air as it does on hydraulics. You are limiting the amount of air that can enter or leave the cyl. Similar to adjusting the flow regulator on your argon welding tanks. You can limit the amount of gas that passes thru it, a pressure regulator limits the amount of pressure that can pass thru. with air, it much cheaper to adjust the flow and pressure. Flow controls with check valve bypass, $15 or so, pressure regulator, $5 0r $6 bucks.

Pressure and force of the cyl is figured the same way as figureing hydraulic pressure. The amount of pressure times the area of the piston. My way of thinking is if I need to get my hydraulic pressure down to 100psi using a 2 in cyl to achieve 100lbs of down force at mid bar of the saw. I can get the same amount of force using a 2in air cyl and 100psi of air pressure. I am not sure how to compare fluid volumes to air volumes when it comes to figureing flow. A gal of oil has a volume of 231 cuin so to match fluid flows of 1gpm I need to have air flow of 231cuin min, and if pressures are the same, then both systems should perform the same. Air will compress, oil doesnt. I dont know what comparison to make with how the compression factor will influence the final results. With fluid on both ends of the cyl, I would think it takes a certain amount of pressure just to push the oil out of the opposite end you are applying fluid to. Fluid makes friction and friction makes heat. Air can create friction and heat, but that heat is exhausted to the atmosphere

 

[fordf150]

I have the cylinder mounted about 6" past the pivot point on my saw. 1 1/2" cylinder attached and it takes 12" of stroke to run the saw thru its travel. small softer wood. 12" poplar for example i open my flow control wide open. that has the potential to create 2472 lbs of force at the cylinder mounting point. 2 gpm to to flow .1 gallon and it is too slow at times. jsut giving you some real world figures to help calculate from.

 

[muddstopper]

I think force measured at the middle of the bar only needs to be about 50-70lbs. How much of that 2742 lbs of force being transmitted to the mid bar would be determined by the distance between mid bar, hinge point of bar and attachment point of cyl. With out knowing all the numbers, it would be hard to determine how much actual force is being applied at the middle of the bar. Longer the bar, the less force. I have to wonder if you ever have problems with the bar mounting bolts as it would seem that you are applying much more force than is recommended. Have you actually checked pressure at the cyl to see how much actual pressure is being applied.While you might have 1400 psi of available pressure to the cyl., pressure is only built as resistance is raised. I cant question a system that is actually working, and probably wont understand how its is working without seeing it in action.

Here is the type of air flow regulator I was referring to. http://www.mscdirect.com/product/details/80185846, You can see by the schematic printed on the side of the valve that it controls flow in one direction while letting air pass thru the opposite direction at full flow. Using two of these valves, one on each end of the air cyl, will allow you to control flow in each direction. Control the flow, control the speed. I need to do a little more searching, but I am almost 100% sure that they make a similar flow control valve that controls flow and pressure.

 

[fordf150]

pretty good video that shows how mine is set up. I have no clue what the actual pressure is. Never been curious enough to add a gauge and check it. I have done 60 cord of wood thru this processor and the bar still looks new with no burr on the rails and no problems with mounting bolts. I know when the chain gets dull and i am forcing the last few cuts to finish loading the truck that i am maxing out the pressure because the bar will stop moving and i have to lift out of the cut a hair and go again.

 

[ChoppyChoppy]

My conveyor reliefs at around 700psi. Normal use the guage reads maybe 300psi. Don't set it too high, when it jams it will break!

Air is a bad idea, you will fight it when it gets cold. The 18-20 at the shop uses air for bar and splitter return and it's a pain vs my 15-20 which is all hydraulic.

Bar clamp and saw is easy. Just need a relief. Open valve to cut, clamp comes down, once it hits 500 psi it reliefs to the bar cylinder to cut.

My bar has 2 bolts and a large key. I did tear it all up last year, it has full pressure on the up swing and the bar got jammed ammer up in a log.

 

[muddstopper]

Valley, I aint in Alaska. It dont get quite as cold down here as it does up there. A good air dryer will take care of the freeze up. Every piece of equipment we have at work uses some sort of air circuit. Before Manufacturers started putting air driers on the machines, we would fight them every winter. I cant remember the last time I had a air line freeze.

I think you might be confusing relief valves with a sequence valves. The conveyor most likely is using a relief to prevent pressure build up. The clamp/bar is most likely using a sequence valve.

 

[muddstopper]

If you can read my shakey drawing, here is the difference between a relief, sequence and pressure reducing vavle

 

[muddstopper]

Valley, you wouldnt happen to have the schematics for the air controls for your 18-20 processor, would you. I would like to see how blockbuster made it work.

 

[muddstopper]

Did a little figureing on air pressure and cyl size. A 1.5in bore cyl with 100psi will give me a push force of 177lbs. Since I only need about 60lbs of force at mid bar, it should just be a matter of figuring out mid bar lenght, pivot point, and cyl mount point, and then adjusting air pressure to get there.

 

[muddstopper]

Well, went back to the doc Wednesday and he cleared me to go back to work. Been off for 8 weeks and not been able to do hardly anything to the processor. Go back to work Monday, I have 12 days left to work this year and then I take my vacation. Hopefully now that I can actually use my arm, I can get a few things done. Got a lot of plate to cut. Got my plasma torch finally mounted on my homemade track torch. Probably try and get some of the metal cut tomorrow. I have about 300inches of plating to cut out and then weld into the Hbeam. Even tho I wasnt physically able to get much done, I spent a lot of time trying to figure out how to make everything work. I still have to buy a few parts, which is the only advantage of going back to work, I should be able to free up funds to buy some of the stuff I was hesitating purchasing because I wasnt working.

I did a little math while I was off on just how much I have spent on this project so far. I still dont have the engine or the hyd pumps I need. I did buy a few things I couldnt use, but got lucky and sold them all for a profit. taking that profit into account, I am into this processor for just over $2000. I will need to spend at least that much more, but its starting to look like I will be into this processor for less than what some folks have paid for some major brands of wood splitters.

 

[muddstopper]

Finally got back to the processor build today. Made a little progress on the actual splitting parts. Got plate cut and spot welded on top flange. Notched the hbeam in the rear to accept the cyl base mounts. Dont look like much done, but with everything weighing tons and having to use a FEL and cherry pickers to get everything set up. I feel like its been a good day. I still have to cut out all the metal I plan on using to box the beam. Once I get the metal cut, its going to be a all day job just welding everything solid