Patent ID: 8171952

Claim:
A control valve assembly for venting a vapor space of a fuel tank, comprising: a housing defining a chamber with a main opening configured to open the chamber to the tank when at least a portion of the housing is placed in the fuel tank, and further defining a vapor vent passage and a first bypass vent opening; a main float disposed in the chamber and operable for closing the vapor vent passage when fuel in the chamber is at or above a predetermined level; wherein the first bypass vent opening is operable for venting the tank to the chamber even when the fuel covers the main opening; a feature on the main float operable to provide a metered opening of the vapor vent passage between closed and fully open based on a main float position to permit venting therethrough; a cover secured to the housing and defining a first passage for vapor flow to a recirculation line and a second passage for vapor recovery; a second float in series with the main float between the main float and the first and second passages and configured to discriminate liquid from vapor to prevent liquid flow into the first and second passages; and an isolation valve disposed in series with the main float and configured to control venting from the vapor vent passage to the cover by moving upon a predetermined pressure differential acting on the isolation valve to permit venting from the vapor vent passage to the recirculation line and the second passage when the isolation valve moves; wherein the cover defines a second bypass vent opening configured to permit venting of the vapor vent passage to the second passage; and wherein the control valve assembly is configured with an orifice configured to permit venting of the vapor vent passage to the recirculation line regardless of whether the isolation valve moves.