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Determine equivalent vacuum for water depth

  1. Jul 6, 2015 #1
    Hello, I need to figure out the max water depth a motor will operate without water ingress. The plan is to use a vacuum pump to create differential pressure and correlate that to water depth. My issue is the correlation between the vacuum and pressure. Can someone please provide a formula for determining the equivalent water pressure which the motor can withstand based on the vacuum I can hold? The Max. Vacuum, of the pump is 25 Inches of Hg.

  2. jcsd
  3. Jul 6, 2015 #2
    I'm pretty sure rho g h will be in there somewhere.
  4. Jul 6, 2015 #3
    Mercury is 13.5 times denser than water , so 25 inHG = 337.7 inH2O = 28 ft of water.
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