Problems with absolute pressure and gauge pressure in process applications
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In standard manufacturing processes, both gauge pressure and absolute pressure are used to represent the process parameters of a system. For example, if the maximum operating pressure of a certain device is 10.0 MPaG in gauge pressure and 10.1 MPaA in absolute pressure, then the design pressure is taken as 1.1 times the highest pressure; thus, it becomes 11.0 MPaG in gauge pressure and 11.11 MPaA in absolute pressure. Now the question is: why isn’t the design pressure of this device minus 1 equal to its gauge pressure? There’s an extra 0.01 MPa – what’s the problem? ?
This is a math problem; the extra amount of 0.01 comes from 0.1 times 1.1
This post was last edited by ylb913 on 2018-7-4 21:45. The design pressure is 1.1 times the operating pressure; both the design pressure and the operating pressure here should refer to gauge pressure, and it should not be converted to absolute pressure before multiplying by 1.1.
Thank you. It’s all based on gauge pressure; there’s no need to switch to using absolute pressure for calculations
The design pressure and operating pressure are gauge pressures, as the 1 atmosphere in absolute pressure does not need to be borne by the equipment