Helpful Hint - Pressure Gauges:

Bourdon Tube Gauges are the most commonly used of all pressure gauges. They are used almost exclusively for measurements in industrial hydraulic and pneumatic systems, where pressure above 15 PSI are expected. Accuracy of Bourdon Tube gauges is good to excellent, dynamic response is fair and static response is excellent. The main working element in the gauge is a tube (a Bourdon tube) shaped like a letter "C". As the pressurized fluid enters this tube, it tends to straighten it, moving the tube tip. The movement displaces a connecting linkage that actuates a pointer on the gauge face.

Differential-pressure gauges are available in Bourdon tube mechanisms. Typically, they have two independent measuring chambers, each connected to a different pressure source. However, they have only one pointer which shows the pressure difference between the two gauges.