FIRE LIMITER FOR DUCTS IN VENTILATION SYSTEMS

摘要

The invention provides a shut-off device for ducts in ventilation systems, comprising a tubular sleeve, a shaft transversely mounted within said sleeve with respect to the axis thereof, a closing plate mounted on said shaft and pivotal from an open position in which the plate extends substantially parallel to the axis of the sleeve to a closed position in which the plate extends across the sleeve, the plate being biassed into the closed position, and a control wire coupled to the plate through a fuse for maintaining the plate at least in a partially open position during normal service whereby during normal service a desired throttling effect may be produced with the aid of the control wire and, in the event that the fuse blows, the plate will automatically move to the closed position.