Fireguard for ventilation ducts - has thermal fuse to automatically close flap under action of excessive heat

摘要

The fire guard (1) is mounted inside the ventilation duct and pivots about a bar (3). It is held in the horizontal, open, position by a thermal fuse device which consists of two plates (17, 16) held together by brazing (15) pivoting about a bar (22). Under the action of excession heat the brazing fuses allowing the top plate (17) to slip, clockwise, relative to the fixed bottom plate (16) and letting the fire guard drop to the vertical closed position. The fire guard can also be opened and closed manually by a handle outside the duct which is held in the open position by a pin on the handle and a lug socket, acting against a return spring.