Fire extinguishing sprinkler

摘要

Sprinkler comprises a frame (1) for connection to a source of fire extinguishing fluid and having a passage (4) through which such fluid may flow along a path. The passage is sealed by a closure (21) in contact with the fluid. The closure is maintained in its passage sealing position by a bowed retainer (31) which is held by a thermally sensitive collapsible strut (41) in such position as to bear upon the closure. When ambient temperature rises to a predetermined level, the strut collapses allowing the retainer to release the closure from the passage and allow flow of fire extinguishing fluid, through the passage. The closure is typically formed from material of poor thermal conductivity thereby preventing cooling of the collapsible strut by the transfer of heat from the strut through the closure to the fire extinguishing fluid in the passage.