B Calculating vacuum -- These numbers do not make sense

Thread starter Ripcrow
Start date Apr 29, 2024
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Manometer Vacuum chamber

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The discussion centers around the confusion regarding the readings from a manometer used to measure vacuum created by a pump. The user reports that the manometer indicates a rise of 40 inches of water, suggesting an impossible vacuum level of 80 inches when considering the need to double the reading. Participants explain that using water in a manometer is problematic due to its vapor pressure and boiling point, which can distort readings. They emphasize the importance of having one side of the manometer open to atmospheric pressure for accurate measurements and suggest providing a diagram for clarity. Overall, the consensus is that the current setup may not yield reliable readings without adjustments or redesigning the system.

May 25, 2024

Ripcrow

Fixed I think. Bought a gauge that went as low as -100 kpa and it went well past that and hard up against the stopper at around where the -130 kpa graduation would have been if had been marked. Must have gone well past that level though as when I repeated the test the gauge only got as low as roughly -110 so I’m thinking the gauge was damaged in the initial test or it found a way to admit a small amount of air into the tank , perhaps through the pump seals. Either way it has proven to be more than is required. Thanks for all your input.