tank question
Last Post 08 Apr 2013 02:56 PM by Niel. 1 Replies.
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mature student
New Member
New Member

08 Apr 2013 06:08 AM
    I went for a job interview and testing. One question is bothering me as to the reasoning. here is the question - if you answer could you please respond with the reasoning/physics. ty

    I'm assuming all tanks/vaccum and pipe sizes to be equal as no info was provided.

    Tank "A" draws off the top down into Tank "B" into the top.

    Tank "C" draws off the top down into Tank "D" into the top.

    The difference is Tank "C" and Tank "D" are much further apart then Tanks A and B. Both are a straight verticle drop.

    At first I thought of head pressure being the difference but if they are drawing out of the top of the higher tank then doesn't the vaccum
    determine the rate - regardless of the drop ?

    The answers I had to choose from was- which empties faster, Tank A (into B) or Tank C into D or the same.

    Basic Member
    Basic Member

    08 Apr 2013 02:56 PM
    Assuming that:

    1. Total starting head A-B is the same as the total head C-D
    2. The size of tank A is the same as tank C
    3. The inside diameter of the pipes or tubes between the tanks is the same
    4. The liquid in the tanks is the same at the same temperature
    5. The pipe material is the same with the same inside surface conditions (finish and fouling)

    Then the tank system will the shortest run will drain the quickest as the result of frictional losses. This difference may be small but if the length of the pipe is long enough or the tanks are big enough. It will be meassurable.