| 摘要 |
A leak detection device for restricting the flow of liquid fuel through the undergound fuel conduit whenever the leakage exceeds a predetermined rate of flow. The device includes a valve in the conduit that is movable between a first position to permit a first volumetric rate of flow for quickly pressurizing the conduit to a predetermined pressure, and a second position to permit a second volumetric rate of flow is that is much less that the first volumetric rate of flow. The valve includes a seal member which is extendable radially outward of the valve. A valve seat for the valve is provided and has a plurality of slots therein to provide fluid communication between the fuel inlet and outlet of the device. Once the conduit is pressurized to the predetermined pressure, the valve moves from its first position to its second position resulting in the seal member being sealingly aligned with each of the slots thereby preventing the flow of the fuel through each of the slots.
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