Sprinkler head having protuberant ridge valve seat

A fire protection sprinkler head comprising a base adapted for connection to a source of fire retardant fluid under pressure, a throat in said base having an exit orifice through which fire retardant fluid can flow, a valve seat defined by said base about the periphery of said throat exit orifice, and a resiliently flexible valve disk element disposed across said throat and impressed upon said valve seat in sealing engagement,

• said valve seat comprising an arcuate profile segment beginning at said throat exit orifice in said base, with a protuberant ridge disposed about the periphery of said throat and immediately adjacent thereto, defining a valve seat surface in the region of the crest of said protuberant ridge, and said valve seat further comprising a recessed surface segment disposed radially outwardly of said throat exit orifice and of said protuberant ridge, the recessed surface being divergent from said protuberant ridge, and
• said valve disk element comprising a disk spring having a sealing surface adapted to be impressed upon the valve seat surface of said protuberant ridge in sealing engagement over an annular region inward of the peripheral edge of said valve disk,
• said disk element maintaining sealing engagement in said region of said crest during flexing of said disk element,
• the diameter of sealing engagement of said seat surface remaining at all times closely adjacent to the diameter of the throat exit orifice.