A fire protection sprinkler has a body with an orifice and a coaxial outlet for delivery of fire protection fluid from a source; a cap that resists flow of fluid from the outlet in a sprinkler standby condition; and an actuator securing the cap in the standby condition and releasing the cap in an operating...http://www.google.se/patents/US6123153?utm_source=gb-gplus-sharePatent US6123153 - Fire protection sprinkle and release mechanism
