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Fill time for a pressurised system

  1. May 30, 2012 #1
    Hi everyone

    I have a problem whereby I need to calculate the time to fill and then deflate a catheter balloon. This consists of a hand pump connected to a long tube which then widens out to the balloon vessel. I need to reach a certain pressure in the balloon. The balloon is already expanded and it is assumed no further expansion of the material will occur.

    I know the volumetric flow rate (Q) from the hand pump. The length (L) of the tube is 1400mm. I have calculated the pressure drop across the tube (delP).

    How to I determine how long it will take to fill both the tube and the balloon from vacuum to a given pressure and then how long to pull a vacuum on the system? Any help appreciated.

    I previously used Pressure = mass*Gas Constant*Temperature/Volume. I did this at intervals until the pressure in the vessel equaled the pressure required, giving me the time required. However I found that this did not match my experiment. (The calculated times were much greater than the actual)

    note to mod: feel free to move this thread
    Last edited: May 30, 2012
  2. jcsd
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