Liquid filter

Claim 1

A liquid filter for filtering a liquid flow, comprising: a filter housing having a peripheral wall, a base, and an open end opposite said base; an unfiltered-liquid inlet and a clean-liquid outlet communicating with an interior of said filter housing; a first filter element, having a hollow cylindrical shape, arranged in said interior of said filter housing, said liquid flow travelling from an exterior to an interior of said first filter element; a second filter element, having a hollow cylindrical shape, arranged inside of said first filter element, said liquid flow travelling from an exterior to an interior of said second filter element; a separating wall arranged between said first and second filter elements; a center tube arranged in said filter housing, said center tube collecting clean liquid supplied from said first and second filter elements; a drain outlet in said base for draining said filter housing; an outlet valve in said base operable to open or close said drain outlet; a removable lid for closing the open end of the filter housing; an axially slidable member separate from said filter elements and slidably disposed between the peripheral wall of the housing and the exterior of said first filter element, said member having a first end abutting said lid and a second end engaging said valve such that axial movement of said member will operate said valve, whereby removal of said lid from said housing permits said slidable member to move to a first position in which said valve is operated to open said drain outlet, and whereby installing said lid to said housing moves said slidable member to a second position in which the valve is operated to close said drain outlet.