Infrared smoke sensing system self aligns

. The FireRay 5000, developed and patented by Fire Fighting Enterprises in Hitchin, combines an infrared transmitter and receiver and works in conjunction with a reflecting prism on the other side of the building. Smoke in the beam path reduces reflected power, which if it falls below a pre-determined level, results in an alarm signal. Sensing path length can be up to 100m, so that building settling or subsidence resulting in 1m of movement, will lead to a to a 0.6 degree misalignment. Until now, the usual solution has been to ramp up beam power to compensate, but the new unit is able to realign itself. The way it does this is to try a move in one direction to see if the reflected signal is greater or lesser, and if it is less, try a move in the opposite direction until the signal strength in maximised. Setup also makes use of the auto alignment facility. Once the detector head is connected, an integral laser, aligned along the optical path of the beam, can be activated. This allows the reflecting prism to be sighted quickly and with confidence. Once the laser has been used to coarsely align the beam, the “AutoOptimise” beam alignment system takes over