DSI-1 HR Automatic Fire protective Smoke Curtains are totally gravity fail safe and incorporate the latest in electronic technology. As a result DSI-1 HR Curtain is one of the most advanced, yet cost effective systems on the market.
Limit switch control has been replaced with current-limiting systems to determine the upper position of the curtain. The 24v motor will retract the curtain until the bottom bar pulls against the underside of the head box. The current drawn by the motor will begin to rise, this will be detected by the motor control circuit and the supply will be stepped back to a holding voltage of approximately 4 volts.
Upon receipt of a fire or test signal the holding voltage will be removed to the motor. The weight of the bottom bar will force the motor windings to return generating a back EMF. This facility ensures a controlled descent of the curtain even in the event of total power failure.
This method of operation should be used to deploy the system at all times. A curtain that is powered down under normal test conditions from either mains power or the battery supply is only proving that it can deploy when powered. This does not confirm the ability to fail safe.
The curtain fabric has a “Panama” weave which offers a more even surface and allows a tighter interlacing of the fabric edges. The tensile strength of Panama weave fabric is 10% greater than other fabrics due to the constant thread tension. The extra strength helps the curtain to keep its shape while retracting onto the roller.