| 摘要 |
VENTED FUEL TANK CAP AND VALVE ASSEMBLY A vented fuel tank cap and valve assembly is described including a pressure relief valve with a main valve member mounted at a main vent opening through the fuel cap. A fusible metal ring of low melting point is provided in the pressure relief valve to enable such valve to open in the event of fire to prevent an explosion. A float valve may be provided to close a secondary vent passage for venting fuel fumes through the valve stem portion of the main valve member. The float valve includes a tubular cage member attached to such valve stem portion and containing a hollow float member with a cavity opening through the bottom of such float. A metal ball is provided within the cage member beneath the float member to hold the float valve closed when the tank tips to an inverted position and to trap liquid fuel in such cavity so that such fuel flows out of the cavity to open the valve when the tank returns to an upright position to prevent the float valve from sticking closed. An auxiliary seal portion may be provided on the main valve member to increase the tank pressure required to remove the main valve member from the tank after the fusible ring melts so that liquid fuel is not discharged from the tank prematurely. |
