| 摘要 |
An excess flow valve comprising a valve body defining a passage for a flow of fluid therethrough, the passage having an inlet and an outlet for fluid, a magnetically attractable closure member movably located within the passage for movement toward and away from the outlet, a seat located adjacent to the outlet for receiving the closure member. A flow restriction means located in the passage for defining at least two flow paths for fluid along the passage, flow restriction means including a retaining means comprising a permanent magnet for retaining the closure member in one of said flow paths and away from said seat whilst there is a flow rate of fluid through the passage which is less than a predetermined rate, the retaining means releasing the closure member when the flow rate of fluid through the passage equals or exceeds said predetermined rate so that the closure member moves toward the outlet to engage said seat and shut off flow of fluid through the outlet.
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