Fluid filter cartridge with replaceable filter element

A reusable fluid filter cartridge, comprising:

• (a) a housing having an annular peripheral wall, a closed end, and an open end;
• (b) an annular collar disposed in said open end of said housing, said annular collar having internal threads and peripheral sealing surface means adjacent said internal threads;
• (c) means for securing said annular collar to said housing at said open end;
• (d) a replaceable filter element disposed in said housing to define a fluid inlet chamber between said filter element and said housing, said filter element having a hollow cylindrical core which opens to a first end of said filter element, permitting filtered fluid to flow therefrom, and having a closed second end, said filter element having an outer diameter that is smaller than an inner diameter of both said housing and said collar to permit removal of said filter element through the open end of said housing;
• and
• (e) a mounting head assembly having:
• (i) external threads for mating with said internal threads of said annular collar;
• (ii) an annular channel adjacent said external threads;
• (iii) a sealing ring disposed in said annular channel, said sealing ring creating a first seal in cooperation with said peripheral sealing surface means of said annular collar when said external threads of said mounting head assembly are threaded into said internal threads of said annular collar;
• (iv) fluid inlet means extending through said mounting head assembly in fluid communication with said fluid inlet chamber;
• and
• (v) a tubular filter attachment member extending into said open first end of said filter element, said filter attachment member having a fluid outlet port in fluid communication with said hollow cylindrical core and an outer surface sealingly engaging said open first end.