| 摘要 |
A T-shaped housing has a first channel defined by the housing which when coupled to a fluid distribution conduit forms a segment of the conduit. The housing has a second channel defined by the housing normal to the first channel and in fluid communication therewith. The interface between the first and second channels forms a mouth through which fluid passes from the first channel into the second channel. A sphere is disposed in a chamber beneath the second channel and is confined by fins to movement across the first channel generally toward and away from the mouth of the second channel. The sphere closes the mouth when seated against it. An outlet of the second channel is coupled to a riser. The rate of fluid flow from the first channel through the riser is restricted, for example, by a sprinkler head. In normal operation when the rate of fluid flow through the riser is so restricted, the interaction of the fluid pressure above and below the sphere together with gravity cooperate to prevent the sphere from closing the mouth of the riser channel. When the restriction is removed from the riser channel beyond a select threshold, for example by damage to the riser, the free flow of fluid out of the riser creates a fluid pressure differential sufficient to overcome the action of gravity on the mass of the sphere and the sphere is urged against the mouth of the riser channel thereby closing it. |
