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Question about liquid expulsion from a spray bottle

  1. Jun 19, 2010 #1
    Hello,

    I’m new to this forum, and this may seem elementary, but I can’t be sure of my thinking on the subject, so I’ll post the question here.

    The question concerns the following. I have two household spray bottles, each of the same size. Each has its hose down nearly to the bottom of the liquid. The only difference is that one bottle is almost full, and the other bottle has only a small portion of its liquid remaining, but in both bottles, the bottom of the hose easily reaches into the liquid. The bottom of the hose is at the same point in both bottles.

    Question: Will there be any difference in the ease of spraying from the two bottles? Will the bottle with only a small amount of liquid result in the spray action being less effective? I realize that once the liquid in the smaller portion container drops below the bottom of the tube, no more spray will emanate from that bottle, but in the meantime, will there be any difference in the amount or velocity of the spray from the two bottles?

    In other words, does the extra weight of the liquid in the bottle with more liquid assist in the process?

    Thank you,
    Louis
     
  2. jcsd
  3. Jun 19, 2010 #2
    I see the point you're driving at, but perhaps you'll have to rephrase it with a different example, the example of the spraybottle is null and void as you can see here

    http://www.howstuffworks.com/question673.htm

    the mechanism makes it pretty much independent of the water it's in all together.
     
  4. Jun 19, 2010 #3
    Thanks for your reply. I read the reference that you cited, but I didn't see that the article made any reference to the amount of liquid having any effect, so I'm still not certain of whether it would make a difference.
    Louis
     
  5. Jun 19, 2010 #4
    Look at the diagram, it clearly shows that the spray bottle takes in water before you spray it, and keeps it in via a one-way system, so the only water it expels is water it had previously stored. The spray is only dependant on what's inside the cylinder chamber, not the actual bottle.
     
  6. Jun 19, 2010 #5
    Yes, but how does it "take the water in"? Is it a siphon process, and cannot the weight of the additional water assist in allowing it to "take the water in" more easily? I'm just asking.
    Louis
     
  7. Jun 20, 2010 #6

    rcgldr

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    Homework Helper

    I'm not sure how much additional pressure above ambient you get from 15 or so centimeters of fluid. The main affect would be a slightly slower release rate of the trigger.

    Note that in the past, crude atomizers or sprayers like a "flit gun", simply had a open ended tube perpendicular to an air flow (the other end in the fluid). The air flow is diverted away from the open end, creating a low pressure vortice. Somce carburetors also utilize variations of open tube perpendicular to flow as well as one or two venturi stages.

    Example diagrams showing end of tube protuding into inner venturi stage, although the tube itself may be angled, the opening is angle cut so that it faces away from the air flow.

    http://www.secondchancegarage.com/articles/images/carbtheory/drawing2.gif

    http://www.motorera.com/dictionary/pics/c/carb.gif
     
    Last edited: Jun 20, 2010
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