In a steam pressure gauge, which part straightens from steam pressure to indicate a reading?

A steam pressure gauge typically operates using the Bourdon tube, which is a curved hollow tube that straightens under pressure. When steam enters the gauge, it exerts pressure on the inside of the Bourdon tube. As the pressure increases, the tube straightens out, and this movement is transmitted to a dial through a series of mechanical linkages, resulting in a visual indication of the pressure.

The ability of the Bourdon tube to convert pressure into mechanical movement is critical for accurate readings. Its design allows it to be sensitive to small changes in pressure, making it a reliable choice for measuring steam pressure in various applications. The other components mentioned—pressure rings, spring mechanisms, and diaphragms—serve different functions in pressure measurement and do not directly translate steam pressure changes into a gauge reading in the same manner as the Bourdon tube does.