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Help with reverse siphon break?

  1. Apr 5, 2004 #1
    Help with reverse siphon break????

    Hey there,

    Not sure if this is possible but...

    I was wondering if there was a way to set something up so that one liquid would siphon into a lower container and stop when the liquid reached the level of the tube opening without using any sort of valve???

    Basically I need a large volume of liquid to feed into a small volume bottle then shut off when the smaller bottle gets to a certain level. I think there may be a way to do it using either or both the siphoning effect and capillary effect.

    The main point is to minimise (actually eliminate) moving parts like valves.

    Any ideas???

  2. jcsd
  3. Apr 6, 2004 #2


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    Science Advisor

    You could just make the larger container air-tight. Now as the liquid drains from it through the tube, it gurgules as the air goes back up the tube to make up the displacement of liquid removed. Once the liquid reaches the level of the tube opening, no more air is available to allow any more liquid to be displaced.

    I have a gas can for my lawn mower that works this way. It works ok. With something of a higher viscosity and a smaller opening it would work better, like trying to get motor oil out of those plastic bottles if you tip them completely upside-down instead of pouring them into the funnel.

  4. Apr 6, 2004 #3
    To do it once, is feasable, repetitions are another story....
  5. Apr 6, 2004 #4
    Mmmm, yes, that might just work. For some reason I was getting stuck on the larger container 'siphoning' the fluid out rather than taking the feed tube out of the bottom of the container. Now that I think about it, you can get pet water feeders that you attach an inverted bottle to and it feeds in water when the water gets below the level of the opening.

    Nice work Cliff_J. I'll have to get experimenting.


    Raavin :D
    Last edited: Apr 6, 2004
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