The SA-3 seismic safety switch is said to provide triaxial vibration detection and is suited for protecting vulnerable structures from ground borne vibration events and incorporates a range of safe shutdown options.
The switch features three high-integrity low-noise piezoelectric seismometers positioned at 90° to each other along with the associated alarm circuitry housed within a robust weatherproof steel enclosure.
It is said to be seismically qualified to IEEE-344 and utilises technology operationally proven in harsh environments. The switch operates on seismic events and when the signal from any axis exceeds the pre-set alarm level, the alarm relay is activated.
The sensors consist of a unique system of matched piezoelectric elements arranged in a ‘reciprocal’ configuration providing a functional test capability. Application of a 1Hz signal to the calibration crystal element mechanically excites the measuring elements resulting in a defined signal output which can be used to perform a full loop check of the seismic switch. Such a facility is essential for applications where the switch is located in a hazardous area and requires full-proof testing on a regular basis.
As well as the usual seismic and EMC approvals the SA-3 switch is also available for functional safety applications up to SIL-2 and can also be provided in an explosive-proof housing for intrinsically safe applications.
