Spring tensioned ventilation shutter - has spring moving disc to shut position on release by temperature sensitive locking device

摘要

Ventilation shutter has a baseplate in a housing enclosed by an edge strip and with a semicircular opening in it. A ring encloses the opening, and incorporates grooves radially open on the inside. A semi-circular disc rotates about the ring centre, and a locking device engages with a groove in the ring in the open position, releasing at a preset temperature and allowing the disc to shut the opening off. A spring (41) acts between disc (2) and housing (1), being sufficiently pre-loaded to move the disc into the shut position on release at the locking device. Alternatively, the shutter can be so installed that the disc drops into the shut position under gravity on release.