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  1. #1
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    The number 25,400 relates to

    a. Microns per inch
    b. BTU per Ton
    c. CFM per Ton
    d. CFM per HP
    e. Watts per HP



    For extra credit, how did they choose the number 25,400?



  2. #2
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    Jun 2001
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    a.
    cr=?

  3. #3
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    A. rounding
    Quote
    “Engineers like to solve problems. If there are no problems handily available, they will create their own." Scott Adams

    "We can't solve problems by using the same kind of thinking we used when we created them."
    Albert Einstein

  4. #4
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    Aug 2004
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    A. microns per inch
    Gee,extra credit?
    2.54cm=1 inch,so
    25,400micrometers=1 inch

  5. #5
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    Originally posted by highlimit
    A. microns per inch
    Gee,extra credit?
    2.54cm=1 inch,so
    25,400micrometers=1 inch

    Excellent! I grant you a gold star sir!


  6. #6
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    Jul 2003
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    Hey he was looking at my paper!

  7. #7
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    Geez, Norm, you must be psychic. I wish you'd posted that yesterday. I looked all over for that same thing this morning before finding it.

    I was trying to figure out why they didn't make direct reading analog pressure type micron gauges. After finding out that there are over 3/4 of a million microns between zero and 30" inches of vacuum, I realized that in order to display the graduations at 1/10" apart, it would take over 1 mile of gauge space to accomodate them. Guess I need a bigger truck!!

    Actually most of the digital ones only go from 50-5000, but still.....

  8. #8
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    Originally posted by midhvac
    Geez, Norm, you must be psychic. I wish you'd posted that yesterday. I looked all over for that same thing this morning before finding it.

    I was trying to figure out why they didn't make direct reading analog pressure type micron gauges. After finding out that there are over 3/4 of a million microns between zero and 30" inches of vacuum, I realized that in order to display the graduations at 1/10" apart, it would take over 1 mile of gauge space to accomodate them. Guess I need a bigger truck!!

    Actually most of the digital ones only go from 50-5000, but still.....
    Zero microns is a perfect vacuum. Since there are 25,400 microns per inch, a micron gauge at atmospheric pressure would read 762,000 microns. So the micron gauges don't start indicating microns until we get down to 5000 microns or so. By limiting the instrument range the accuracy is increased and the cost of the instrument is decreased.


  9. #9
    a........because of reading high limits answer

  10. #10
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    I had to do this by process of elimination A micron per inch
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