| 摘要 |
<p>An automatic on-off sprinkler head (11) includes a housing (12) that defines a primary chamber (61), a pilot chamber (60), an inlet orifice (19), and outlet orifice (16), a fill port (37) providing limited flow between the inlet orifice (19) and the pilot chamber (60) and a release port (54) for discharging fluid from the pilot chamber (60). Supported by the housing (12) between the inlet (19) and outlet (16) orifices is a flexible diaphragm (28) with wall portions that open a flow path between the orifices when in an open position and close the flow path when in a closed position. The diaphragm (28) has first surface portions exposed to the primary chamber (61) and surface portions opposite the first portions and expand to the pilot chamber (60). In response to a predetermined difference in pressure between the pilot (60) and primary chambers (61), the wall portions are moved to the open position and are retained in closed positions by less than the predetermined difference in pressure. A pilot valve (52) controls fluid flow through the release port (54) and in response to a fire condition, a sensor (53) moves the normally closed pilot valve (52) into an open position and thereby produces a differential pressure across the wall portion that opens the diaphragm (28) main valve. The use of a flexible diaphragm (28) as a valve closure eliminates any requirement for movable seals and thereby provides a valve that is highly resistant to leakage when in a closed condition and sensitively responds to fire conditions by establishing fluid discharge between inlet (19) and outlet (16) orifices.</p> |
