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Pulling Vacuum through Manometer

Pulling Vacuum through Manometer

Pulling Vacuum through Manometer

(OP)
Hello,

I am referencing my old Thermo book, but seems I am missing something.

I want to pull vacuum on water in a basic manometer which is of square construction out of stainless steel.  One side is open to atmosphere, A1 and P1.

Am I wrong for thinking the ratio of A1 to A2 will have an affect on how it acts? In other words, if A2 on the vacuum side is 3 times larger than A1, for every inch of water I pull on A2, A1 will drop 3 inches?

I am trying to figure the size of my manometer and the ratio of A1 to A2 so I can pull about 25 inches of water.

Any equations or input would be awesome. Thanks.

RE: Pulling Vacuum through Manometer

Yes, you are wrong. Area has no effect.That is why manometers are so easy to calibrate. 25" is 25".

RE: Pulling Vacuum through Manometer

(OP)
OK Thanks. I did the math and it showed that area has no control over it... Just wanted to make sure I wasn't missing anything, I was hoping I was!

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