Let us now, talk about the Diaphragm Pressure Gauge in little more detail. A metallic
diaphragm pressure gauge uses a thin flexible diaphragm of materials like brass, bronze,
monel, Ni Span C etcetera. All these materials are very good elastic property. The force
of the pressure against the effective area of the diaphragm causes a deflection of the
diaphragm the motion of diaphragm is a measure of pressure and the motion of
diaphragm operates an indicating or recording type instrument. This is a schematic of a
diaphragm element.
So, when a pressure is applied here there is a Translational movement of this diaphragm
element. This movement of the diaphragm can be used to move a pointer and scale
mechanism. So, the deflection can be rate and that will be taken as a direct measure of
the pressure being applied. Diaphragm can also be of nonmetallic elements such as
rubber, plastic, leather etcetera. Diaphragm Gauges are typically Spring loaded, so that
the range and sensitivity can be varied. For nonmetallic diaphragms they are usually
spring loaded because, nonmetals do not have good elastic property like metal such as
brass, bronze, monel, Ni Span C etcetera. Diaphragm elements can also be used for
measurement of differential pressure as well as absolute pressure.