Posted to News on 23rd Mar 2016, 00:00
Seismic safety switch for high integrity protection
High integrity seismic protection of critical assets such as oil, gas, nuclear and hydro-electric installations, pharmaceutical and medical facilities, where accurate detection of structural vibration in conjunction with safe shut-down procedures is an essential requirement. Sensonics offers a range of solutions which are ideally suited to most applications.
The SA safety seismic switch is a good example of Sensonics’ expertise in developing innovative seismic monitoring and protection systems. The SA-3 seismic safety switch provides triaxial vibration detection and is ideal for protecting vulnerable structures from ground borne vibration events and incorporates a range of safe shutdown options, depending on the application.
The SA-3 model features three high-integrity low-noise piezoelectric seismometers positioned at 90º to each other along with the associated alarm circuitry housed within a robust weatherproof painted steel enclosure. It is 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 available for functional safety applications up to
SIL-2 and can also be provided in an explosive-proof housing for intrinsically safe applications.
