Cut-off device against fire transmission in ventilating conduits

摘要

At least one flap is pivotably located on its lower edge in the housing and can drop from an upwardly directed open position into a closed position covering the lower opening of the housing. A bi-metal tab holds the flap in its open position and under the effect of heat releases the flap for the closure movement. Material is provided which foams under the effect of heat and in the event of fire fills the housing in a sealed manner. The bi-metal tab (28) is arranged parallel to the upper edge of the flap (24) in the open position and on heating parallel to the plane of the flap located in the open position moves away from it and with a recess in its free end engages around the upper edge of the flap at least on the side pointing in the closure direction.