Patent ID: 7175761

Claim:
A filter assembly having a housing open at one end, an annular filter media/core assembly disposed in said housing, an end plate secured to the housing and closing the open end thereof, the end plate having first inlet opening means, second inlet opening means and outlet opening means, a combination valve disposed between the annular filter media/core assembly and the end plate for controlling fluid flow through the first inlet opening means and the second inlet opening means, the combination valve being annular and including a first portion cooperating with the first inlet opening means and a second portion cooperating with the second inlet opening means, the second portion having more resistance to fluid flow than the first portion, whereby, the combination valve is configured such that when there is no fluid flow the first portion prevents fluid flow through the first opening means from within the housing, and in operation, the first portion will yield prior to the second portion and fluid flow will pass through the first opening means, the annular filter media/core assembly and then be discharged through said outlet opening means and when the annular filter media/core assembly begins to clog, pressure upstream of the first portion will build and upon attainment of a predetermined pressure, the second portion will open the second inlet opening means and fluid flow can pass through the second inlet opening means and out the outlet opening means bypassing the annular filter media/core assembly.