What is a Diaphragm Pressure Gauges? Diaphragm Pressure Gauges is a pressure measuring instrument that uses a flexible diaphragm as its sensing element to measure and display process pressure. Where are Diaphragm Pressure Gaugess used? They are commonly used in chemical, pharmaceutical, food processing, water treatment, petrochemical, and other industrial process applications. Why use a diaphragm pressure gauge? Diaphragm gauges are useful when measuring corrosive, viscous, contaminated, or otherwise difficult process media because the diaphragm can isolate the measuring mechanism from the process.