Low pressure liquid filter cartridge and method of making

A method of making a low pressure cartridge for liquid filtration comprising the steps of:

• locating at a first open end of a tubular member, a first end cap member including a cylindrical side wall sized to fit telescopically with a first end portion of the tubular member, the first end cap member further including an end wall transverse to the cylindrical side wall for covering the first open end, the cylindrical side wall and the first end portion of the tubular member together including at least two circumferential raised rings and at least an equal number of circumferential grooves, the grooves being sized and spaced axially from one another to simultaneously received all of the raised rings;
• and
• pressing the first end cap member and the tubular member together until each of the raised rings is seated in a separate circumferential groove, interference between the circumferential grooves and the raised rings seated therein constituting the only means coupling the first end cap member and the tubular member together;
• locating at a second open end of said tubular member opposite the first open end, a second end cap member including a cylindrical side wall sized to fit telescopically with a second end portion of the tubular member at the second open end, the second end cap member further including an end wall transverse to the cylindrical side wall for covering the second open end, the cylindrical side wall of the second end cap member and the second end portion of the tubular member together including at least two circumferential raised rings and at least an equal number of circumferential grooves, the grooves being sized and space axially from one another to simultaneously received all of the raised rings;
• and
• pressing the second end cap member and the tubular member together until each of the raised rings is seated in a separate groove, interference between the circumferential grooves and the raised rings seated therein constituting the sole means coupling the second end cap member and the tubular member together.

A method of making a low pressure cartridge for liquid filtration comprising the steps of:

• locating at a first open end of a tubular member, a first end cap member including a cylindrical side wall sized to fit telescopically with a first end portion of the tubular member, the first end cap member further including an end wall transverse to the cylindrical side wall for covering the first open end, the cylindrical side wall including at least three circumferential raised rings on an inner surface thereof and the tubular member including at least three circumferential grooves on an outer surface thereof, the grooves being sized and spaced axially from one another to simultaneously receive all of the raised rings,
• each of said circumferential grooves and said raised rings being generally triangular in radial cross-section with a pair of generally planar, beveled walls, said beveled walls forming a lesser included angle of about 70.degree. or less with respect to a radial axis of the respective member supporting the beveled wall;
• operatively disposing at least one O-ring circumferentially around said first end portion of the tubular member;
• pressing the first end cap member and the tubular member together until each of the raised rings is seated in separate circumferential groove and said at least one O-ring is compressed between the first end cap member and the tubular member to prevent liquid leakage therebetween, with the O-ring, the circumferential grooves, and the raised rings seated therein constituting the only means coupling the first end cap and tubular members together;
• providing orifice means through the first end cap member for passing liquid through the filter cartridge;
• providing a loose filtering agent disposed in the tubular member;
• and
• providing first porous retaining means at least partially held between the first end cap member and the tubular member at the first open end for passing a liquid between the orifice means and the loose filtering agent while retaining the loose filtering agent in the tubular member.

A low pressure cartridge for liquid filtration, comprising:

• a tubular member having a first open end;
• a first cap member comprising a cylindrical side wall configured to fit telescopically with said first open end of said tubular member, and an end wall contiguous with and generally transverse to said cylindrical side wall for covering said first open end of said tubular member,
• said tubular member and said cylindrical side wall of said end cap member together having at least two circumferential raised rings and at least two circumferential grooves formed therein, wherein
• said grooves are sized and spaced axially from one another to simultaneously receive all of said rings so that said end cap member is securable to said tubular member by pressing said end cap member onto said first open end of said tubular member, thereby seating said circumferential rings in said grooves, whereby the interference between said circumferential grooves and said raised rings seated therein comprises the only means of attachment between said first end cap member and said tubular member.