| 摘要 |
A fuel dispensing nozzle has a diaphragm responsive to vacuum for shutting off the flow of fuel through the nozzle, the diaphragm chamber having a vent to atmosphere through a tube extending to the mouth of the nozzle spout and closeable by fuel in the tank being filled to cause vacuum to actuate the diaphragm and shut off the fuel flow through the nozzle, a valve in the vent tube, a piston for closing the vent tube valve in response to vapor pressure in the tank being filled, a vapor return conduit providing vapor communication between the interior of the tank being filled and the fuel source, the vent tube valve piston being exposed to vapor pressure in the vapor return conduit, whereby to shut off the flow of fuel through the nozzle when predetermined vapor pressure occurs in the tank being filled, and additional means holding the vent tube valve closed and closing the vapor return conduit to prevent vapor leakage from the fuel source except when the spout is inserted in the filler inlet of a tank, and operable upon insertion of the spout into a tank to release the vent tube valve and thereby break the vacuum acting on the automatic shut-off valve diaphragm to open the shut-off valve and permit the flow of fuel from the nozzle through the spout into the tank to be filled.
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