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Optimal orifice size for continuous manifold pressure
Last Post 26 Sep 2012 08:39 AM by pityocamptes. 4 Replies.
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pityocamptes
New Member
New Member
Posts:4

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21 Sep 2012 10:26 AM
    I have a small pump system for a project that requires a small manifold. The total volume of the manifold and the tubing is 2.9828 cu inches. Here is my pump specs:

    Inflation time < 8s (from 0-200 mmHg in a 100cc tank)
    Air flow > 70mL/min
    Max pressure > 360mmHg
    Leakage max 36mmHg/15sec from 300mmHg at 70cc tank
    Pump time - 7sec on / 7sec off


    From the pump is a 3/16" x 12" tube (volume = .3311 cubic inches) which attaches to a small cylindrical manifold (1"x3" - volume = 2.3571 cubic inches) that has two air rails (each air rail (1/4" x 3" -volume = .2946 cubic inches). Total volume should be 2.9828 cubic inches.

    I was hoping to see if someone could figure out how big of an orifice I would need on each rail for maximum pressure, within the 7 seconds on, 7 seconds off (basically optimal orifice pressure and size where manifold drops stays at a constant positive pressure at the end of the 7 second off phase wherein the 7 seconds on phase starts to pump and build pressure. Any help on this would be appreciated. Thanks.
    Nathaniel
    Basic Member
    Basic Member
    Posts:193

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    23 Sep 2012 11:07 AM
    First why are you mixing units for this problem? You should either keep with the original SI units of the original problem statement or convert everything over to Imperial units.

    Next to maximize the pressure at the end of a cycle you want to minimize the size of the orifices. Zero orifice would be perfect. Something is missing from the problem definition.

    Are you trying to maximize the total flow out of the system?

    Niel Leon
    engineering.com
    pityocamptes
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    Posts:4

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    24 Sep 2012 02:42 PM
    Yes, trying to maximize flow out of the system given the 7 seconds on and 7 seconds off for the air pump. Sorry about mixing the units, the manifold was made with imperial and the pump specs that were given was SI.

    Basically, trying to figure out, based on the pump specs and manifold design, what size orifice would be optimal for maximum flow and pressure. Zero orifice is not an option as I require air flow out of the orifices (dual air rails as defined above). Any help appreciated. Thanks!

    Here are the manifold specs in CC's...

    The total volume of the manifold and the tubing is 48.8793 CC

    From the pump is a .4762 cm x 30.4800 cm tube (volume = 5.4257 CC) which attaches to a small cylindrical manifold (2.5400 cm x 7.6200 cm volume = 38.6259 CC) that has two air rails (each air rail is .6350 cm x 7.6200 cm) - volume = 4.8276 CC).
    pityocamptes
    New Member
    New Member
    Posts:4

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    25 Sep 2012 01:34 PM
    Any info? Bump... thanks.
    pityocamptes
    New Member
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    Posts:4

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    26 Sep 2012 08:39 AM
    Anyone?
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