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Log Splitter, why is bigger better ?

Discussion in 'Firewood, Heating and Wood Burning Equipment' started by staywarm53, Aug 9, 2006.

  1. staywarm53

    staywarm53 ArboristSite Lurker

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    I know I am overlooking some small well known fact :dizzy: , but why is bigger better? I know that if there wasn't a pressure relief valve (usually 2250?) that pressure would keep increasing and you would get more and more pressure, therefore 30 tons is better than 10 tons.
    But doesn't the relief valve dump preesure at 2250? then how do you build up to more tons. can anyone give me a better idea of how the relief valve works?
    I have some very hard wood that my splitter wouldn't split last October, It wont now either :( Its a tractor pto driven 540 rpms? It has a 3 to one gear settup so I'm spinning the pump 1620 times. I have thought of raising the relief pressure from whatever its at up 300 lbs. I bought a tee and 3000 lb gauge(to be put on). Are relief pressures easy to set and it is safe(main concern), Do you think the 300 lb increase will make the spliiter work better? Any suggestions are appreciated.
     
  2. BlueRidgeMark

    BlueRidgeMark Addicted to ArboristSite

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    Given the same fluid pressure, a bigger ram will produce more tonnage of push. It's simple arithmetic: Pressure per square inch (PSI) times area of ram. If you increase either one, you get more tonnage.

    Same pressure times bigger ram = more tons.

    Higher pressure times same ram = more tons.

    But the higher the pressure, the more problems with blowouts. More wear and tear, too. So, to get more tonnage, the better choice is a bigger ram.


    As for WHY more tons, just to split bigger wood. You'll also put less strain on the spiltter if it's got bigger components.
     
  3. ray benson

    ray benson Tree Freak

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    If your relief valve is set at 2250 lbs.then when your splitting a tough piece the pressure can rise to 2250 and does not build up any higher. And will maintain 2250 til you stop trying to split the piece. There is usually an allen adjustment screw on the control valve to set the relief pressure. I would look for a liquid filled or glycerin filled gauge 0-3000 lbs. Cheap gauges will not last because of vibration. And the tee also has to be for high pressure.
     
  4. staywarm53

    staywarm53 ArboristSite Lurker

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    I think I see now how the relief valve works now. Tonnage is pressure for the whole cylinder, wheras the reilef valve is a measure of only one square inch. For example, you might have a 10 ton splitter but depending on your cylinder size and wood hardness you might only have 600 or1800 lbs per square inch of pressure on the relief valve.
    Thanks for your help guys it is greatly appreciated ! !
     
  5. BlueRidgeMark

    BlueRidgeMark Addicted to ArboristSite

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    Yep. You've got it. The gauge is measuring PSI, or Pounds per Square Inch. The power in hydraulics is in how it multiplies the pressure put out by the pump, by applying that pressure to a larger area, namely, the end of the ram. It's simple arithmetic. If I've got 10 square inches of ram, and I apply just 15 pounds of pressure, I get 150 pounds of force from that ram. 10 times 15 equals 150. If I make it 150 PSI of hydraulic pressure, I get 1500 pounds of force, or 3/4s of a ton!

    Take that up to 1500 PSI, and I now have 15,000 pounds of force, or 7 1/2 tons of power at my fingertips.

    Take a look at the chart below, and see how ram size and pressure work together.



    [​IMG]


    Now, how FAST you can move that ram depends on how much VOLUME your pump can put out at a rated pressure. And of course, to move more force more quickly, takes more horsepower, so you need a bigger engine. If you have plenty of time, you could get 50 tons out of a 3.5 horse motor, in theory. It would just take longer to move the ram.
     
  6. staywarm53

    staywarm53 ArboristSite Lurker

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    thank you, the chart is a big help ! I have a gauge on the system now and I'll know by tommorrow(or this evening) if my cylinder seals are good.
     
  7. BlueRidgeMark

    BlueRidgeMark Addicted to ArboristSite

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    Glad it helped. But now you got me started! :D Sometimes a picture is worth 10,000 words. Or numbers. Check this out: a 4", 5", and 6" ram at various pressures.

    [​IMG]
     

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