Large Property Cleaning

Discussion in 'Heavy Equipment & Pavement' started by AWJ Services, Oct 13, 2013.

  1. AWJ Services

    AWJ Services LawnSite Platinum Member
    from Ga
    Posts: 4,276

    Last I heard all of the equipment I use has an engine in it so not sure what your saying has to do with what an excavator or skid is capable of hyd wise?
     
  2. mxridernorth

    mxridernorth LawnSite Senior Member
    Posts: 306

    Hydraulic output horsepower can't be greater than engine horsepower. My T153 has max 38 HP available so theoretically this is the maximum that you can utilize.
    gpm = 1714 x HP/psi. So at 3000 psi, my machine's theoretically max flow is 22 gpm. My TL140 has 81 HP and at 3000 psi the theoretical max flow would be 46 gpm.
     
  3. AWJ Services

    AWJ Services LawnSite Platinum Member
    from Ga
    Posts: 4,276

    So what would the flow be at 1000psi?
     
  4. Nelson M Martin

    Nelson M Martin LawnSite Member
    from Ontario
    Posts: 192

    come on guys make it simple
    max hydraulic gpm specs on all equipment are given without any load on hydraulics
    Max hydraulic psi specs are given for example:: "dead heading the mulcher drum"
    so the max gpm and max psi cannot be seen at the same time
    Example
    the harder u use the attachment on any of the machines mentioned, the higher the hydraulic pressure will rise, So (not all machines are the same) but at some point in pressure the releif valve will start to divert some of the oil back to hydraulic tank. If u stall the mulcher head to a stop the gpm at motor will be zero but the releif valve is deverting the oil into tank again
     
  5. Digdeep

    Digdeep LawnSite Bronze Member
    Posts: 1,840

    Thank you. The original point I made was that you will not see the max hyd gpm given on a spec sheet at the advertised max psi on that same spec sheet.:drinkup:
     
  6. mxridernorth

    mxridernorth LawnSite Senior Member
    Posts: 306

    Max psi and max flow can be seen at the same time. In the example given above it's the point at which the relief valve opens.
     
  7. Digdeep

    Digdeep LawnSite Bronze Member
    Posts: 1,840

    Not on any SSL or CTL that I have put a flow meter on. The actual high flow near the "max" psi on the spec is not even close to the flow on the brochure.

    Maybe if the engine was able to put out significantly more torque to drive the pump as the pressure builds up due to resistance from the flow meter, but the flow drops off dramatically not far above 2500psi on the Bobcats I've put a flow meter on.
     
  8. AWJ Services

    AWJ Services LawnSite Platinum Member
    from Ga
    Posts: 4,276

    What started this was I stated that on mini ex's the adv flow rating( aux circuit) would be equal to the actual hp available on that circuit. It has went downhill from there.LOL
     
  9. AWJ Services

    AWJ Services LawnSite Platinum Member
    from Ga
    Posts: 4,276

    Using your formula

    gpm=1714 x 38/1000

    gpm = 65

    Wow the pump mysteriously does not have a linear flow? :hammerhead:
     
  10. AWJ Services

    AWJ Services LawnSite Platinum Member
    from Ga
    Posts: 4,276

    I will add that I was told the min ex flow specs are given at 1000 psi.
     

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