Filters

The filter of any preceding claim wherein the housing has a side wall and the axially extending fluid conduit is disposed in the side wall of the housing

The filter of any preceding claim wherein the axially extending fluid conduit extends from the fitting at the top of the filter to the bottom of the housing.

The filter of any preceding claim wherein the fitting is an inlet fitting or an outlet fitting.

The filter of any preceding claim wherein the filter cartridge includes an end cap and wherein the housing includes a wall adjacent to the end cap and a radial passage which extends along at lease one of the end cap of the filter cartridge and the wall of the housing and fluidly communicates between the axially extending fluid conduit and the filter cartridge chamber.

The filter of any preceding claim further comprising a keying mechanism cooperatively arranged with the housing and the filter cartridge to center the filter cartridge in the filter cartridge chamber.

A filter comprising:

• a filter cartridge having an end cap and
• a housing having at least one fitting and defining a chamber, the filter cartridge being disposed in the chamber with the end cap of the filter cartridge adjacent a wall of the housing, wherein the housing has a radial passage extending along at least one of the end cap of the filter cartridge and a wall of the housing and fluidly communicating between the fitting and the filter cartridge chamber.

The filter of any of claims 17, 11 and 12 wherein the keying mechanism comprises mating shapes on the interior bottom wall of the housing and the bottom of the filter cartridge.

A filter comprising:

• a filter cartridge including a filter element having non-radially extending pleats, the height of each pleat being greater than (D−d)/2 and less than or equal to (D2−d2)/[4(d+2t)] where D and d are the outside and inside diameters, respectively, of the pleated filter element at the crests and roots of the pleats and t is the thickness of a pleat leg, and
• a housing fitting around the filter cartridge and having an inlet and an outlet defining a fluid flow path, the filter cartridge being disposed in the housing in the fluid flow path and the housing and the filter cartridge being arranged to reduce hold up volume and dead zones in the fluid flow path.

The filter of any preceding claim wherein the annular channel between the filter cartridge and the housing has an area on the order of the area of an inlet fitting or an outlet fitting.

The filter of any preceding claim wherein the housing has an inclined bottom surface, thereby enhancing removal of bubbles in the liquid from the filter.