Biflow drier with improved filtration

A bidirectional filter drier, comprising:

• a tubular casing having opposed ends;
• end caps at said opposed ends,
• a flow port in each of said end caps,
• first and second check valve assemblies supported in said casing at said opposed ends, and
• a cylindrical core of molded desiccant material centrally supported on each end by said valve assemblies, each of said check valve assemblies including a first valve to allow fluid to flow from a respective flow port in an adjacent end cap around the periphery of the desiccant core and radially inward toward the center of the core, and a second valve to allow fluid to flow axially outward from the center of the desiccant core to the flow port in the adjacent end cap,
• an outer depth type filter media layer in surface-to-surface contact with and circumferentially surrounding said desiccant core to separate particles in the fluid passing radially inward through the desiccant core, said outer filter media arranged to allow a portion of fluid passing therein to bypass the desiccant core, said outer filter layer having a filtration efficiency at least as great as the desiccant core,
• a disc-shaped depth-type filter media layer adjacent each end of said desiccant core between said core and said check valve assemblies to separate particles in the fluid passing axially outward from the center of the desiccant core, said end filters each having a filtration efficiency greater than the desiccant core, and
• a perforated plate disposed between each end of the desiccant core and each end filter, each perforated plate also supporting an end of the outer filter and allowing fluid to pass from the outer filter directly to the end filters and bypass the desiccant core.

A bi-directional filter drier, comprising:

• a casing having opposed ends;
• end caps at said opposed ends,
• a flow port in each of said end caps,
• first and second check valve assemblies supported in said casing at said opposed ends, and
• a molded desiccant core centrally supported by said valve assemblies, each of said valve assemblies including a first valve to allow fluid to flow from between a respective flow port in an adjacent end cap and the radial periphery of the desiccant core, and a second valve to allow fluid to flow axially between the center of the desiccant core and the flow port in the other adjacent end cap, said fluid flowing radially through the desiccant core to remove water contaminants, and
• an outer filter media layer circumferentially surrounding said desiccant core and a flow path provided between a radially-outer surface of the filter media layer and the casing to allow fluid flow therebetween, said filter media layer extending between said valve assemblies to separate particles from the fluid passing radially through the filter media layer and the desiccant core, said outer filter media arranged to allow a portion of fluid passing therein to bypass the desiccant core.