1. #1
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    Default Pressure dump tanker

    I'm looking for info on tankers that may use a pressure dump (other than a vacumn tanker).

    Vac tankers can "reverse" the pump and put 15psi into the tank to "push" the water out the dump. In theory don't get the gradual slowdown in GPM as tank water (head) level drops. This actually work as well as it sounds in theory? Have not worked around a vac tanker. Purchase of one is not going to happen.

    I'm thinking a large compressor to do the same on a conventional tanker. Pump air into the tank as water flows out so you maintain constant head pressure. Perhaps truck mounted or perhaps one compressor located at the dump site to service each tank in the shuttle relay. Obviously would need shutoff on the overflows/vents. 3000gal+ tankers.

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    Hmmm.....I don't know if I'd try that....vacuum tankers are engineered to hold pressure/vacuum, whereas an ordinary tank is not designed for that (ever noticed the big reinforcing rings on a lot of vacuum trucks?). When you apply pressure to a vessel that is not intended to contain pressure, bad things can happen. Even what you might consider a small amount of pressure can be enough to make the vessel fail. I work in industry and I've seen it happen.

    Not saying it can't be done, but I would consult with someone who engineers pressure vessels to evaluate your tank and see if it could contain the pressure you are talking about. 15 psi doesn't sound like a lot, but that's actually a good deal of pressure on a tank that's only designed to handle atmospheric and head pressure.
    Last edited by dmleblanc; 01-07-2006 at 01:22 AM.
    Chief Dwayne LeBlanc
    Paincourtville Volunteer Fire Department
    Paincourtville, LA

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    Default hmmm

    Well im no expert but the pressure on a conventional tank is deffanly a big issue you should look at. talking about the vac tankers and runing a vacum pump in reverse to create pressure. A compresser in reverse would create vacum so basicly your talking about doing the same thing and those tanks are desided much diffrent.

    However I do rember reading about something called a "jet dump" or "jet assested dump" were a pipe from the pump is put in the tank at a certain angle and the pump takes water from the tank and pumps it in the tank throw the pipe to achevee what you are talking about. (it has its draw backs that the vacum dosnt but would still do what you want). I think its in my essenchals book ill check it later if i can and let ya know just some food for thought deff check on the tank press. hope that helps

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    Default pressure dump tanker

    You defiantly do not want to pressurized a standard fire apparatus tank with much of any pressure. The tank people tell me they are only tested at 2 psi. or in that range. A vacumn tanker is built more like a pressure vessel and can take higher pressures.

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    Takes a pretty good size pump to make 15 psi in a dumping tank and I WOULD NOT try it unless it was designed as a pressure/vac tank.Unless of course you're looking for an "elliptical"tank. T.C.

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    Default more info

    not much in my book on jet dumps so I searched it on the net not to much there a few fire departments that have tankers with jet dumps try searching it in google and maybe give those departments a call and see what they think.

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