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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. |
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