| 摘要 |
A fluid filter, such as that used to filter engine oil in an automotive vehicle, is provided with a combination anti-drainback and relief valve. The relief valve permits oil to bypass the filter if the latter should become clogged, and the anti-drainback valve prevents oil from leaking from the filter when the vehicle engine is not operated. The combination anti-drainback/relief valve includes a shoulder which is disposed between the filtering medium and a supporting flange therefor carried by the base of the filter, and also includes an inwardly extending annular portion which normally closes passages through the flange which permit communication between the inlet and outlet of the filter, and an outwardly extending portion which seals against the base of the filter to trap fluid within the filter when the vehicle engine is off. The valve element includes a spring steel member which is encapsulated in rubber sealing material. The spring steel member includes a plurality of radially extending, circumferentially spaced, relatively movable fingers on the inner and outer peripheries thereof, and the rubber sealing material encapsulates both the fingers ad the spaces therebetween. The fingers exert a resilient biasing force tending to keep both the anti-drainback and relief valves closed until a predetermined pressure differential is attained thereacross. Of course, the pressure differential required to open the anti-drainback valve is much lower than that required to open the bypass valve.
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