Electrically regenerable diesel particulate filter cartridge and filter

A diesel particulate filter comprising

• (a) a casing having at least two ends;
• (b) means for connecting said at least two ends of said casing to an exhaust system;
• (c) means for supporting at least one diesel particulate filter cartridge;
• and
• (d) at least one diesel particulate filter cartridge comprising
• (A) a substantially rigid, electrically resistive tube having two ends and an outer slotted surface having a plurality of slots, one of said ends of said electrical resistive tube being blocked, said electrically resistive tube having a length and a circumference, a current path length across said length of said electrically resistive tube which is longer than said length of said electrically resistive tube, and current path lengths around said circumference having portions bounded on opposite sides by slots, wherein all of said current path lengths having the bounded portions are greater in length than said circumference, wherein said substantially rigid, electrically resistive tube has circumferential stiffness that is less than 40 percent of the circumferential stiffness of a comparable electrically resistive hollow, solid tube, and wherein said electrically resistive tube is not expanded metal;
• (B) a filtering element comprising inorganic fiber covering said outer slotted surface of said electrically resistive tube;
• and
• (C) means for applying a voltage across said electrically resistive tube to heat it above the combustion point of entrapped diesel exhaust particulate,
• said electrically resistive tube being positioned such that when a voltage is applied across said electrically resistive tube, sufficient heat is transferred from said electrically resistive tube to said filtering element to burn off entrapped diesel exhaust particulate,
• wherein said two ends of said electrically resistive tube extend between said at least two ends of said casing and wherein said at least one diesel particulate filter cartridge is supported in said casing by said supporting means.

A diesel particulate filter cartridge comprising:

• (a) a substantially rigid, hollow, tubular support member having an outer surface with openings extending from said outer surface to an inner surface and two ends;
• (b) a filtering element comprising inorganic fiber covering said openings of said outer surface of said substantially rigid, hollow, tubular support member, said filtering element having an outer surface;
• (c) a slotted electrically resistive tube, said slotted electrically resistive tube having a plurality of slots, an inner surface, a length, and a circumference, a current path length across said length of said slotted electrically resistive tube which is longer than said length of said slotted electrically resistive tube, and current path lengths around said circumference having portions bounded on opposite sides by slots, wherein all of said current path lengths having the bounded portions are greater in length than said circumference, wherein said substantially rigid, electrically resistive tube has circumferential stiffness that is less than 40 percent of the circumferential stiffness of a comparable electrically resistive hollow, solid tube, and wherein said electrically resistive tube is not expanded metal;
• and
• (d) means attached to said electrically resistive tube for applying a voltage across said slotted electrically resistive tube to heat it above the combustion point of entrapped diesel exhaust particulate,
• said electrically resistive tube being positioned with said inner surface of said electrically resistive tube over said outer surface of said filtering element such that when a voltage is applied across said electrically resistive tube, sufficient heat is transferred from said electrically resistive tube to said filtering element to burn off entrappad diesel exhaust particulate.

A diesel particulate filter comprising:

• (a) a casing having at least two ends;
• (b) means for connecting said at least two ends of said casing to an exhaust system;
• (c) means for supporting at least one diesel particulate filter cartridge;
• and
• (d) at least one diesel particulate filter cartridge comprising
• (A) a substantially rigid, hollow, tubular support member having an outer surface with openings extending from said outer surface to an inner surface and two ends, one end of said support member being blocked;
• (B) a filtering element comprising inorganic fiber covering said openings of said outer surface of said substantially rigid, hollow, tubular support member, said filtering element having an outer surface;
• (C) a slotted electrically resistive tube, said slotted electrically resistive tube having a plurality of slots, an inner surface, a length, and a circumference, a current path length across said length of said slotted electrically resistive tube which is longer than said length of said slotted electrically resistive tube, and current path lengths around said circumference having portions bounded on opposite sides by slots, wherein all of said current path lengths having the bounded portions are greater in length than said circumference, wherein said substantially rigid, electrically resistive tube has circumferential stiffness that is less than 40 percent of the circumferential stiffness of a comparable electrically resistive hollow, solid tube, and wherein said electrically resistive tube is not expanded metal;
• and
• (D) means for applying a voltage across said slotted electrically resistive tube to heat it above the combustion point of entrapped diesel exhaust particulate,
• said electrically resistive tube being positioned with said inner surface of said electrically resistive tube over said outer surface of said filtering element such that when a voltage is applied across said electrically resistive tube, sufficient heat is transferred from said electrically resistive tube to said filtering element to burn off entrapped diesel exhaust particulate, wherein said two ends of said hollow, tubular support member extend between said at least two ends of said casing and is supported in said casing by said means for supporting.