Spin-on filter assembly

Abstract

A fluid filter for assembly onto a filter head includes a combination of features such that the assembly of the fluid filter onto the filter head establishes radial flow paths within the fluid filter. The filter head includes an externally threaded outer wall and includes an annular inner wall which defines a flow opening. The inner wall is shaped with a protruding portion and a substantially horizontal bearing surface. The fluid filter includes an enclosing outer shell and a filtering element positioned within the outer shell. A support spring is positioned in the base of the outer shell so that it is axially positioned between the outer shell and the filtering element. An internally threaded nutplate is assembled to the outer shell and threadedly engages the externally-threaded outer wall of the filter head. An inner seal is positioned between the nutplate and the primary filtering element and is designed so as to define a hollow interior. Threaded engagement between the filter head and the nutplate begins the installation procedure. As threaded engagement continues, the protruding portion is inserted into the hollow interior and the bearing surface abuts up against the upper surface of the inner seal. With continued threaded engagement, the bearing surface pushes the inner seal and filtering element axially downward in the direction of the support spring, causing the inner seal to move axially away from the nutplate creating a radial flow path between the inner seal and the nutplate.