| 摘要 |
There is disclosed a family of check and/or pressure relief fluid valve utilizing a spring biased annular diaphragm element for valving. In a single-function form there is disclosed a simple check valve. In a dual-function form there is disclosed a check valve also having a pressure relief function permitting reverse flow above a predetermined pressure differential, this form being disclosed in an automotive fuel tank filler tube cap (i.e. a "gas cap"). There is also disclosed an improved filler tube cap construction and seal therefor. In a multifunction form there is disclosed a fluid valve capable of relieving a source of fluid under pressure to a primary outlet at a first very low pressure and additionally to a secondary outlet at a higher pressure. This valve also acts as a check valve by preventing the pressure of the fluid source from dropping below that at the secondary outlet. There is also disclosed an arrangement for using this multifunction valve in an evaporative emission control system for a motor vehicle having an internal combustion engine. All of the valves disclosed are particularly suited for gaseous fluids.
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