1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Why doesn't my air vacuum device work?

  1. Jun 9, 2013 #1
    I think I sort of know the answer but I'm still wondering how I can achieve what I want to achieve.

    I basically want to use the stored 'work' in the compressed air can to pressurize a different container and while doing so, taking in particulates from the ambient air to be contained into the new container.

    I tried this with a can of compressed air computer cleaner (flurocarbons) and a container of a gallon of milk, the pressurization was fine but the 'sucking' did not occur.

    I believe it is because the pressure in the new container is more than the ambient pressure, also without valves perhaps my idea has no hope of working...

    This device is based on the atomizers of perfume bottles...what am I not understanding?

    The secondary container (gallon of milk) is not equal to the compressed air can pressure, even starting from the beginning (ambient pressure in milk container) and starting the pressurization process, there is no 'vacuum effect' noticeable on the end of the perpendicular tube relative to the parallel high velocity flow... why? WHY!!! WHY!!!!!

    When I tried this, there was some water in the gallon of milk container.

    Anyway, I'd appreciate the help.

    Attached Files:

  2. jcsd
  3. Jun 9, 2013 #2

    Jano L.

    User Avatar
    Gold Member

    I do not know why your device does not work. But you should be able to enhance the sucking effect by making the gas flow faster, for example by decreasing the cross-section of the pipe in the place where the liquid enters. Also, if the final container is closed, you may need greater pressure in source to be able to compress the resulting aerosol into the container.
  4. Jun 9, 2013 #3


    User Avatar

    Staff: Mentor

    You are correct: the venturi effect makes the static pressure at the "ambient air" opening lower than in the tube from the compressed air can to the container, but it is probably still higher than atmospheric pressure.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook