Patent ID: 8230873

Claim:
A valve assembly for controlling fluid communication between a vapor space of a fuel tank and a vapor outlet, comprising: a housing defining a chamber configured to be open to the tank when at least a portion of the housing is placed in the fuel tank, and further defining a vapor vent passage in fluid communication with the chamber; wherein the chamber is in selective fluid communication with the vapor outlet through the vapor vent passage; a main float disposed in the chamber and operable to move to a position in which the main float restricts venting through the vapor vent passage when fuel in the chamber reaches a predetermined level; wherein the housing defines a bypass vent opening that connects the vapor space to the vapor outlet through the vapor vent passage; wherein the bypass vent opening is above the predetermined level; a second float exposed to fuel in the fuel tank outside of the chamber and movable independently of the main float to control venting of the vapor space through the bypass vent opening to the vapor vent passage in response to at least one operating condition in the fuel tank outside of the chamber; a pressure-sensitive diaphragm sealingly mounted to the housing around an aperture in the housing in exposure to the vapor space on one side and to the vapor outlet on an opposing side and movable in response to a predetermined pressure differential between the vapor space and the vapor outlet to permit venting of the vapor space through the bypass vent opening to the aperture and then to the vapor vent passage, the pressure-sensitive diaphragm thereby adjusting venting from the vapor space in response to the predetermined pressure differential; and wherein the housing is configured with a notch; said notch establishing fluid communication between the bypass vent opening and the aperture when the pressure differential is less than the predetermined pressure differential and the diaphragm is not moved, thereby permitting venting through the bypass vent opening to the aperture and then to the vapor vent passage.