THERMAL SEAL Russian patent published in 2004 - IPC

FIELD: shut-off fire-fighting devices sensitive to temperature rise and mounted in pipe lines handling highly inflammable and inflammable media. SUBSTANCE: proposed thermal seal has body with branch pipes, flow section, seat and outer sleeve, flapper valve and its locking mechanism which is sensitive to temperature rise. Flapper valve locking mechanism is located in outer sleeve whose interior is insulated from outside medium by cover provided with gasket and is communicated with flow section of body by means of through hole. Mounted in through hole in body is bush with fork located in outer sleeve. Said fork is provided with ears for spring-loaded stops and swivel coil with rope wound on it. One end of this rope is secured on coil and other end is passed through bush to flow section of body and is connected to flapper valve. Secured on end faces of coil are ratchet wheels with teeth which are engageable with swivel stops. Stops are made from low-melting materials at different melting points. Ratchet wheels are mounted on end faces of coil at angular shift in such position that after breaking of stop at lower melting point, flapper valve is partially shut-off under action of flow of working medium and gravity force of movable parts of seal. EFFECT: enhanced reliability and universality of seal. 2 cl, 3 dwg