Back-flushable filter cartridge assemblies

A filter cartridge assembly comprising:

• a filter cartridge having a generally cylindrical filter medium which defines a cylindrically shaped core space, and a pair of end caps fixed to opposite ends of said filter medium, and
• a threaded base member having detent projections;
• wherein
• at least one of said end caps is annular and has an interior cylindrical surface defining an interior space in alignment with said core space and provided with interrupted threads defining detent spaces;
• wherein
• said at least one end cap is threadably coupled with said threaded base member such that said detent projections are seated in respective said detent spaces to thereby minimize unintended threaded uncoupling of said at least one end cap and said base member;
• and wherein
• said filter cartridge assembly further comprises a truncated generally conically shaped seal skirt operatively associated with said at least one of said end caps;
• wherein
• said base member includes a truncated conical base conformably shaped to said seal skirt, wherein said seal skirt is sealingly engaged with said base when said one end cap and said base are threadably coupled to one another.

A filter cartridge assembly comprising:

• a coreless filter cartridge having a generally cylindrical filter medium which defines a cylindrically shaped core space, and a pair of end caps fixed to opposite ends of said filter medium,
• a base member;
• and
• an elongate permanent reusable core element having a length of one end removably inserted into said base member, wherein
• said core element includes an annular set ring coaxially rigidly fixed to, and axially spaced from, said one end thereof to establish said length when said one end of said core element is removably inserted into said base member and said set ring is seated against said base member;
• wherein
• at least one of said end caps is annular and has an interior cylindrical surface defining an interior space in alignment with said core space and provided with interrupted threads defining detent spaces, and wherein
• said base member includes threads provided with detent projections;
• and wherein
• said at least one end cap is threadably coupled with said threaded base member such that said detent projections are seated in respective said detent spaces to thereby minimize unintended threaded uncoupling of said at least one end cap and said base member.

A filter cartridge assembly comprising:

• a coreless filter cartridge having a generally cylindrical filter medium which defines a cylindrically shaped core space, and a pair of end caps fixed to opposite ends of said filter medium,
• a base member;
• and
• an elongate permanent reusable core element having a length of one end removably inserted into said base member, wherein
• said core element includes an annular set ring coaxially rigidly fixed to, and axially spaced from, said one end thereof to establish said length when said one end of said core element is removably inserted into said base member and said set ring is seated against said base member;
• wherein
• said base member has an interior annular recessed step, said set ring being seated within said step;
• and wherein
• said filter cartridge assembly further comprising an annular seal which is in sealing contact with an upper edge of said base member and with said set ring.

A filter cartridge assembly comprising:

• a filter cartridge having a generally cylindrical coreless filter medium which defines a cylindrically shaped core space, and a pair of end caps fixed to opposite ends of said filter medium, and
• a base member;
• said base member including threads each provided at an upper terminal extent thereof with a downwardly protruding detent projection;
• wherein
• at least one of said end caps is annular and has an interior cylindrical surface defining an interior space in alignment with said core space and provided with interrupted threads,
• said interrupted threads having adjacent ends defining respective detent spaces therebetween, and wherein
• said at least one end cap is threadably coupled with said threaded base member such that said downwardly protruding detent projections at said upper extents of said threads are seated in respective said detent spaces to thereby minimize unintended threaded uncoupling of said at least one end cap and said base member.