FIRE VALVE FOR AIR DUCTS Russian patent published in 2001 - IPC

FIELD: fire-fighting equipment; applicable in prevention of flame spreading through air ducts of ventilation system. SUBSTANCE: device has body with turning flaps installed on axles and connected with fusible lock. Swelling reinforced fireproof material is applied to body internal surface and to external surfaces of box-like flaps made of plates zigzag in cross-section and filled with heat-insulating material. Centers of turning flap axles are located on line spaced from flap plane at some distance, and length of fasteners connecting flaps is less than thickness of flaps. Valve has fixing mechanism located on handle for flaps opening and having spring-loaded retainer coming in contact with limiter located on valve body. Fusible lock is located in removable access hole of body side part and has catch in the form of rod installed on pin secured in access hole for rotation. EFFECT: higher operating reliability of valve. 4 cl, 8 dwg