Automatic on-off fire sprinkler head

An automatic on-off fire sprinkler head comprising:

• housing means defining a primary chamber, a pilot chamber, an inlet orifice, an outlet orifice, a fluid flow path between said orifices, a fill port providing limited fluid flow between said inlet orifice and said pilot chamber, and a release port for discharging fluid therefrom;
• flexible diaphragm means supported by said housing means directly in said flow path between said inlet and outlet orifices, said diaphragm means comprising diaphragm wall portions shaped and arranged to open said flow path between said orifices when in an open position and to close said flow path when in a closed position, said diaphragm means being further shaped and arranged to have first surface portions exposed to the fluid pressure in said primary chamber and surface portions opposite to said first surface portions and exposed to the fluid pressure in said pilot chamber, and wherein said diaphragm wall portions are moved to said open position in response to a predetermined difference in fluid pressure between said pilot and primary chambers and are retained in said closed position in response to a difference in fluid pressure therebetween less than said predetermined pressure;
• a pilot valve means closing said release port in a closed position and opening said release port in an open position;
• a temperature sensor for moving said pilot valve means to said open position in response to the occurrence of an ambient temperature above a given level;
• and
• deflector means supported by said housing means and disposed to deflect fluid discharging from said outlet orifice in a fire extinguishing pattern.