Reusable liquid filter assembly

Claim 1

A reusable liquid filter assembly, comprising: a cylindrical housing having a diameter and open ends with bevelled zones adjacent said ends and having internal threading adjacent said bevelled zones; a first removable end wall having a cylindrical segment having an external thread for mating with the internal threading of one of said ends of said housing, an annular channel around the periphery of said cylindrical segment, a sealing ring for seating in said channel for sealing fit against said bevelled zone of said one end of said housing when said first end wall is threaded together with said housing, a central threaded outlet port extending through said end wall for discharging liquid, a plurality of inlet ports located radially about said outlet port and extending through said end wall for receiving liquid into said filter assembly, an annular projection for extending inwardly into said housing, a shoulder formed around said annular projection, a channel formed in said annular projection, another sealing ring for seating in said channel in said annular projection, and an annular gasket affixed to an outer surface of said first end wall; a second removable end wall having a cylindrical segment having an external thread for mating with the internal threading of the other of said ends of said housing, an annular channel around the periphery of said cylindrical segment of said second end wall, a sealing ring for seating in said channel for sealing fit against said bevelled zone of said other end of said housing when said second end wall is threaded together with said housing, a plurality of struts for extending inwardly into said housing when said second end wall is threaded together with said housing, and a closable port extending therethrough; a filter subassembly having a cylindrical filter frame having a smaller diameter than the housing diameter and having slots therein, a filter screen for fitting onto said filter frame, and a first annular filter end cap for fitting over one end of said filter frame, said first filter end cap being provided with rims around inner and outer peripheral diameters of said first filter end cap, said first filter end cap having an inner diameter sized to be seated on said shoulder of said annular projection, with said inner rim sized for sealing fit against said other sealing ring seated in said channel in said annular projection of said first end wall, and said outer rim sized to snugly receive one end of said filter frame and filter screen; a second annular filter end cap for fitting over the other end of said filter frame, said second filter end cap being provided with rims around inner and outer peripheral diameters of said second filter end cap, at least one of said struts of said second end wall being sized to press against said second annular filter end cap to retain said filter subassembly in said housing, said outer rim being sized to snugly receive another end of said filter frame and filter screen; said filter subassembly defining an outer annular chamber between said housing and filter screen for containing liquid to be filtered and an inner chamber within said filter assembly for containing filtered liquid; and bypass valve means for connecting said inner and outer chambers and set to open at a predetermined pressure differential between said inner and outer chambers, said valve means having a flange, said flange having an annular projection for extending into said housing and centering said inner rim of said second filter end cap of said filter subassembly in said housing, said flange being centered in said housing and retained by said plurality of struts of said second end wall.