Mechanical pressure switches are electromechanical devices designed to sense fluid pressure and activate an electric circuit when a preset pressure threshold is reached. They typically employ a spring-loaded diaphragm or piston as the sensing element; when the process pressure overcomes the spring force at the set point, the mechanism moves to open or close a microswitch contact. This purely mechanical actuation means no external power is required for operation, which enhances their reliability and fail-safe characteristics. Mechanical switches remain a staple in industrial automation due to their robust construction, repeatable performance, and cost-efficiency.
Designs offer consistent set-point accuracy (often about ±1% of full-scale range), ensuring reliable and precise triggering at the desired pressure.
Pressure switches are valued for accuracy in control, high reliability, and safety assurance. They provide simple on/off control to maintain process pressures within desired limits and will repeatedly actuate at the calibrated setpoint under varying conditions.
Because of their ruggedness and long-term stability, mechanical pressure switches excel in harsh environments (vibration, extreme temperatures, etc.) where electronic sensors might falter. Crucially, they serve as safety interlocks – if system pressure strays outside safe limits or if power/primary sensors fail, the mechanical switch will directly shut down equipment or trigger alarms, preventing damage and ensuring safe operation.