Diaphragm Switches

Measure pressures relative to atmospheric pressure and are divided into three main groups, each group being based on a different measuring principle. The majority of our pressure switches have a SPDT micro-switch fitted, including versions in ATEX approved housing, but where double pole switching is required, we can supply a range of pressure switches fitted with a DPDT micro-switch.
Diaphragm Switches
consists of either a corrugated metallic diaphragm or a synthetic rubber diaphragm. Metallic diaphragms are more versatile as the diaphragm can be treated to meet the majority of chemical applications, where as synthetic rubber diaphragms are limited to the compatibility of the synthetic rubber. The maximum pressure that diaphragm switches normally operate is 42 bar but they can be overload protected to 200 bar. Diaphragm pressure switches can also be set to switch in vacuum.
Piston Switches
consists of a piston that has a o’ring seal that is either mounted on the piston or in the body. Piston switches are normally used where the pressure is above that of diaphragm switches. Piston switches should not be used on gasses due to the inherent high friction that an o’ring has especially when pressure is not applied for a period of time. Piston switches are for high-pressure applications of up to 700 bar.
Bourdon Tube Switches
consists of a formed tube with one end fixed and the other end free to deflect under pressure and operate an electrical switch. Bourdon tube switches should be used for high pressure gas applications. Pressure ranges up to 600 bar can be supplied.