| 摘要 |
A flow control device, such as a valve, has a body with two portions which define two valve chambers, an inlet, which is coupled to a source of pressurized fluid and which opens into one of the valve chambers, and an outlet coupled to downstream devices, such as sprinkler heads, and which opens into the other valve chamber. A piece of collapsible tubing couples the two valve chambers. A shaft extends into the valve and is provided with a mechanism for pinching the collapsible tubing shut which causes the collapsible tubing to collapse due to the pressure exerted on its exterior by the pressurized fluid surrounding it. A coil spring is attached to the shaft and the valve body. When the valve is closed, i.e., the collapsible tubing collapsed, the coil spring is biased to cause the shaft to rotate if released. The shaft is prevented from rotating by a fusible link. When the temperature to which the valve is exposed reaches or exceeds a predetermined temperature, the fusible link melts. This releases the shaft for rotation and the coil spring rotates the shaft which unpinches the collapsible tubing. This permits the collapsible tubing to uncollapse, thus opening the valve.
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