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Foamy fluid?

Discussion in 'Construction Equipment Attachments' started by Pants, Apr 22, 2020.

  1. Pants

    Pants Well-Known Member

    Joined:
    Mar 6, 2013
    Messages:
    117
    Location:
    Honolulu
    I've got an ancient small Gravely disc-type chipper (like this one: https://tinyurl.com/ycwduaj9) that uses a hydraulic motor and pump to drive an infeed 'impeller" (looks basically like a paddle-wheel, turns at maybe 120RPM) to drag small trees etc into the spinning Cuisinart-style chipping blades. I recently did some maintenance because the infeed wheel was moving in pulses and had lost a lot of feed strength. I think it was a problem with the very-suspect old four-port valve that controls the infeed (fwd-stop-rev) because the most significant part of the maintenance I did was to replace that valve (and I had one on hand...). But I also replaced the fluid feed-hose from the tank to the pump. In a pinch on the weekend, I used a thick-walled 3/4" clear vinyl hose for this in lieu of the 'correct' black low-pressure stuff, and as a result of the transparent hose I've been marveling at the copious entrained air that apparently gets "boiled out" of the fluid when being taken up the one-foot rise from tank to pump. As seen through this hose, the fluid immediately turns white from all the air, even when from cold. Seeing this reminded me I'd never understood why, on irregular occasions, the tank will 'boil over' with the same airy fluid, and now I'm thinking maybe because it's expanded enough to overflow the 5-gallon volume (by at least a gallon, it would seem).
    The pump is a Vickers vane-type, and unremarkable, I think. I took it apart to inspect, found nothing obviously terrible, so I simply put it back together. I use the chipper very irregularly, but ran it for a couple of hours within the last week, and it's performing better (infeed works fine now), so maybe this isn't anything to worry about, but all of that air...is there an obvious problem or remedy?
    Pump has an ID of V101P5P1A20LH. I think the '101' part of that indicates it's the smallest of this range, at 3.3ml/revolution, and since it's driven off center of the main flywheel/disc (that also chips), it's not being run at any insane RPM.
     
  2. John C.

    John C. Senior Member

    Joined:
    Jun 12, 2007
    Messages:
    8,769
    Occupation:
    Machinery & Equipment Appraiser
    Location:
    Northwest
    Small reservoirs need an up side down cone on the suction to prevent vortex from forming and drawing air from above.
     
    highwayghost and 92U 3406 like this.
  3. Pants

    Pants Well-Known Member

    Joined:
    Mar 6, 2013
    Messages:
    117
    Location:
    Honolulu
    It's stock...pretty sure it's just a pipe-fitting welded into the low edge of the 5G rectangular tank. You're describing...what, something like a megaphone pointing down into a tank? That's a standard above-ground fuel-tank intake style I've seen, but those are many orders of magnitude larger.
    New info: after running it continuously for about 90 minutes yesterday, I noticed as I was shutting it down that the fluid was clear of all air, and just warm to the touch (which means it was maybe 20F warmer than when it started up). I don't understand the variations in behavior, but it's turning into a "whatever..." situation.