tryckswitch

A tryckswitch, commonly referred to in English as a pressure switch, is an electromechanical device that closes or opens electrical contacts when process pressure reaches a preset value. It is used to monitor and control pressure in hydraulic, pneumatic, and other systems. The device can be normally open or normally closed and may include hysteresis to prevent rapid cycling.

Construction and operation: A sensing element such as a diaphragm, bellows, or piston deflects under pressure and actuates a mechanical switch or an electronic sensor. In mechanical types a snap-action mechanism provides reliable switching; in electronic types a transducer converts pressure to an electrical signal. Setpoints are adjustable in many models, via a screw, knob, or digital programming.

Types: Mechanical pressure switches (snap-action), differential pressure switches (compare two pressures), vacuum switches (low pressure), and electronic pressure switches (solid-state sensors with analog or digital outputs). Some models include modular ports or wire leads, and others offer push-button calibration for field adjustments.

Applications: Widely used as safety and control devices in boilers and compressors, hydraulic and pneumatic systems, HVAC and refrigeration, industrial automation, automotive sensors (oil and fuel pressure), and irrigation or water treatment installations.

Selection and considerations: Key factors include setpoint accuracy, repeatability, hysteresis, response time, media compatibility, pressure range, electrical ratings, environmental protection (IP rating), installation orientation, and temperature effects. Routine maintenance may involve checking setpoints, seals, and electrical connections to ensure reliable operation.

See also: pressure sensor, pressure transducer, switch.