The spring-disk pressure sensor (Figure 400-6) is used in pneumatic and electronic pressure switches (see Section 417). The sensor is a convex metal spring disk…
Spring-piston elements consist of a piston opposed by a spring. The application of pressure moves the piston. The position of the piston opens or blocks…
Capacitance pressure sensors operate on the principle that the change in capacitance of an elastic element is proportional to the applied pressure. Ranges are 0…
Strain gage electronic pressure transmitters operate on the principle that metallic conductors subject to strain exhibit a change in electrical resistance. The application of pressure…
The resonant wire electronic pressure transmitter operates on the principle that a taut wire vibrates at a natural frequency that varies with wire tension. Resonant…
The diaphragm sensor is a thin flexible metal disk. Pressure applied to one side of the disk causes a deflection that actuates the indicator, transmitter,…
A bellows pressure element expands when pressure is applied to the inside, actuating an indicator, transmitter or controller. Bellows elements are generally used in pressure…
A Bourdon tube (Figure 400-3) is a curved metal tube closed at one end and fixed to a pressure source at the other. Application of…
A manometer is a U-shaped tube filled with a liquid, usually mercury or water. A differential pressure will cause the column on the high-pressure side…
Pressure instruments may use mechanical sensing elements such as Bourdon tubes, bellows, or diaphragms. These elements are mechanically connected to an indicator, recorder, controller, or…