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I want a level sensor for a tank!

  1. Jun 21, 2011 #1
    hey guys,i want a level sensor for a tank, a big industrial one, contains pulp for paper industry, i don't want a continuous data stream, just if it's under a certain level, turns on a pump, and if its over another certain level, turns it off, tell me the type of sensor, and the best manufacturer i could by from, thanks alot.
  2. jcsd
  3. Jun 21, 2011 #2
    A level switch based on the thermal dispersion principle should work.
  4. Jun 22, 2011 #3


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    We used to make our own in the food industry, all a sensor was, was 3 different lengths of round bar pressed into a plastic housing.

    When just the longest and second longest bar was immersed it turned a pump on, when all the bars were immersed it turned the pump off

    We found this idea far better than complex sensors that could be easily damaged.
  5. Jun 22, 2011 #4
    I believe the sensors wolram described above are conductive sensors used where the substance whose level is being sensed is a conductive medium. However, there are other types you can check out, assuming your medium is non-conductive cos i think pulp is non-conductive. Visit the link below and see what u can make of it.

  6. Jun 23, 2011 #5
    we have very satisfying experience with radar level sensors. works on everything.
    go have a look at krohne. pay $4000 and forget about all the installation, fitting cost and emptying andd refilling of alternatives.

  7. Jun 26, 2011 #6
    Float type would probably be the simplest and the cheapest one that you could get..
  8. Jul 9, 2011 #7
    I agree with chetanladha. A float type "pill" switch would be the most reliable and the easiest to service. The pill switches come in a variety of voltages and can be wired to control voltage of the pump contactor.
  9. Jul 9, 2011 #8


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    I was having a hard time imagining any float type that would work well in that type of service, but certainly not a simple pill style. A pill style float would require a pretty clean service, which I don't imagine pulp to be (maybe that's my poor assumption).

    I'm imagining the pulp to be problematic both in clogging up nozzles and accumulating on floats/contacts. To me that means read the level from above where the pulp can't affect it with radar or nuclear (not sure if nuclear would be applicable) or read it from the weight of the tank with a strain gauge (if the density is consistant).

    I don't know that the OP is ever going to return though.
  10. Jul 10, 2011 #9
    We use pill switches in submerged septic and sewage applications everyday. I have them in sewage pump tanks that have been operating for 20 yrs with no failures. These are sealed contact pills. The ones that I use are made by a company called SJE.

    I have worked in pulp and paper, sewage and septic is as harsh.
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