Why do Bourdon tube pressure gauges measure gauge pressure?
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Why do Bourdon tube pressure gauges measure gauge pressure?
Because the outer wall of the Bourdon tube is in contact with the atmosphere.
When you zero the gauge, what you measure is gauge pressure; when it isn’t zeroed, what you measure is absolute pressure. In fact, the difference is just one atmosphere.
The outer wall of the Bourdon tube is in contact with the atmosphere.
I don’t understand what the question means,,,
Gauge pressure is a pressure measured with respect to atmospheric pressure. The Bourdon tube is in an environment at atmospheric pressure, and the pressure inside the tube needs to be compared with the external atmospheric pressure in order to be indicated; its measurement value is based on atmospheric pressure and represents the difference between the pressure being measured and atmospheric pressure. All such measurements are gauge pressures.
The driving force for the deformation of the spring tube is the pressure difference between the medium pressure and atmospheric pressure