A filter assembly includes a housing, a proximal end cap, and a nut plate. The housing defines a longitudinal axis and includes an inner surface surrounding the longitudinal axis. The proximal end cap is disposed within the housing and defines a central aperture. The nut plate is disposed within the housing and includes a flange portion and an outer wall. The flange portion is disposed within the central aperture. The outer wall includes a plurality of protrusions disposed about the longitudinal axis. At least one of the plurality of protrusions engages the inner surface to prevent rotation of the nut plate relative to the housing.

A method for treating a blood specimen with which capturing rates for both a small rare cell and a rare cell having a high deformability can be improved in the case where rare cells are contained in a blood specimen. The method for isolating or detecting a rare cell includes treating a blood specimen using a filter to isolate or detect a rare cell in the blood specimen.

A method for treating a blood specimen with which capturing rates for both a small rare cell and a rare cell having a high deformability can be improved in the case where rare cells are contained in a blood specimen. The method for isolating or detecting a rare cell includes treating a blood specimen using a filter to isolate or detect a rare cell in the blood specimen.

Filtration systems having filter elements having an axial seal member with a variable cross-section are described. The variable cross-section is matched by the non-planar sealing surfaces of the housing and housing cover that receive the filter elements. The non-planar sealing surfaces of the housing and the housing cover prevent proper filtration system function when an unauthorized replacement filter element having a flat axial seal member is installed in the housing.

A filter element includes an upper end disc, a lower end disc, a filter material arranged between the upper end disc and the lower end disc, a dirt pot on the lower end disc, a pin attached at an attachment location and configured to be received within a channel in an installation orientation, the pin extending away from the attachment location along an axis, the pin having a base of a first width at the attachment location, the pin having a free end and a groove defined between the attachment location and the free end, the pin having a second width that defines a circumference of the groove, the second width approximately orthogonal to the axis, wherein the first width is greater than the second width, and an opening in the dirt pot.

Cartridge components are configured to trap the upper end of a concave housing portion to define an enclosure surrounding a filter element. A disclosed embodiment includes a concave metal housing portion and plastic cartridge components, but other materials may be employed. An upper end cap spans the open end of the housing portion and defines at least one fluid flow aperture. A retainer surrounds the housing portion and is secured to the first component, with engagement features on the housing portion trapped between the upper end cap and retainer. The upper end cap and retainer may be secured to each other by spin welding, threads, adhesive or other suitable means. The outside circumference of one or both of the upper end cap and retainer may be provided with lugs, threads, bosses or other features to interface with complimentary features on the head for securing the cartridge to a head.

A filter element comprising a filter media having a first end and a first endcap coupled to the first end of the filter media. The first end-cap includes a flexible first endcap body having a first endcap rigid reinforcing member internally embedded therein. The first endcap rigid reinforcing member may comprise a wire mesh screen and the filter media may comprise a pleated filter media. The filter clement may further comprise a second end-cap coupled to a second end of the filter media. The second endcap may include a flexible second endcap body having a second endcap rigid reinforcing member internally embedded therein.

A filter assembly includes a housing, a proximal end cap, and a nut plate. The housing defines a longitudinal axis and includes an inner surface surrounding the longitudinal axis. The proximal end cap is disposed within the housing and defines a central aperture. The nut plate is disposed within the housing and includes a flange portion and an outer wall. The flange portion is disposed within the central aperture. The outer wall includes a plurality of protrusions disposed about the longitudinal axis. At least one of the plurality of protrusions engages the inner surface to prevent rotation of the nut plate relative to the housing.

A fuel filter assembly includes a filter housing defining a cavity, a center stack having a base component and a top portion. The center stack is positioned within the cavity of the filter housing and attached to the housing, the center stack having an axial aperture in the top portion, the axial aperture having a circumferential surface, and a fuel filter. The fuel filter includes a filter base, an end cap having a top surface and a bottom surface opposite the top surface, an axial extension that extends from the bottom surface, and at least one prong attached to the axial extension, the at least one prong having an axial surface facing away from the top surface that axially locates the fuel filter in the housing against the circumferential surface, a filter element attached to the bottom surface of the end cap, and a pin attached to a filter base.

A fuel filter assembly includes a filter housing that forms a cavity, and a center stack. The center stack is positioned within the cavity and includes an axial aperture in the top portion, the axial aperture having a circumferential surface, and a fuel filter. The fuel filter includes a filter center support. The fuel filter also includes a sword positioned along a surface of the filter center support, an end cap, a filter element attached to an undersurface of the end cap, a water separator at a filter base of the fuel filter, and a pin attached to the water separator. When the fuel filter is positioned within the filter housing, the sword engages with a slot of a center stack of the fuel filter housing and the pin aligns with a channel of the housing.