Pressure-relief devices now have activation detection fitted as standard

Paul Boughton

Elfab is believed to be the first manufacturer to offer this as standard. The company’s ATEX-approved, non-invasive and reusable Integral Flo-Tel sensor is now fitted as standard to Opti-Gard, Safe-Gard, Posi-Gard, Vac-Gard, Arma-Gard, bursting panels, and both flat and domed composite discs.
Unlike most alarm systems, which are activated by the flow created after a bursting disc has operated, the Integral Flo-Tel is installed on the vent side of bursting discs and is activated by the operation of the disc itself. During operation, a magnet arcs away from its rest position, thereby removing the magnetic field from the sensor, and it then comes to rest in a position which no longer influences the sensor. This causes the sensor to switch to its fail-safe condition of an open circuit and a latched alarm condition results. After operation, the bursting disc, complete with magnet, is the only part of the assembly that needs replacing. The sensor probe can be easily withdrawn from the bursting disc holder prior to the holder being removed from the flange, and does not need to be electrically disconnected from the control system.
Similarly, verification of the sensor’s operation is achieved by simply removing the sensor from the bursting disc holder. This triggers the sensor to change state (closed circuit to open circuit) and allows the plant control and monitoring system to confirm that a reading has been detected.
The Integral Flo-Tel is IP65-rated and suitable for use in both chemically aggressive and hygienic environments. Since all of the sensor's electrical parts are non-invasive and situated outside the pipe or vent bore, they are subject to much higher levels of mechanical protection than more traditional membrane warning systems, and therefore benefit from a greatly reduced potential for spurious alarms.
The Integral Flo-Tel also remains unaffected by damage from handling or installation and downstream back-pressure fluctuations.

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