Corona-assisted electrostatic filtration apparatus and method

A corona-assisted electrostatic filtration apparatus for the removal of particulate matter from a gaseous medium, the apparatus comprising:

• a first cathode-anode filter element pair;
• and
• a second cathode-anode filter element pair;
• in which each of the first and second cathode-anode filter element pairs comprises:
• a cathode having a size, shape, and location;
• an anode filter element located in functional proximity to the cathode and comprising a porous fibrous sheet material defining pores in a range of from about 0.1 to about 100 micrometers, with at least a portion of the fibers thereof being uniformly coated with a nonparticulate, elemental metal;
• and
• a means of establishing between the cathode and the anode filter element a nonalternating potential difference having a magnitude which is sufficient to maintain a corona field of ionized gas therebetween;
• in which
• for each cathode-anode filter element pair, the size, shape, and location of the cathode and the magnitude of the potential difference are selected to direct the particulate matter only to selected areas of the anode filter element thereof, such that a portion of the anode filter element remains substantially free of particulate matter;
• and
• the portion of the anode filter element of the first cathode-anode filter element pair which remains substantially free of particulate matter and the portion of the anode filter element of the second cathode-anode filter element pair which remains substantially free of particulate matter do not substantially coincide.

A corona-assisted electrostatic filtration apparatus for the removal of particulate matter from a gaseous medium, the apparatus comprising:

• a first cathode-anode filter element pair;
• and
• a second cathode-anode filter element pair;
• in which each of the first and second cathode-anode filter element pairs comprises:
• a cathode;
• an anode filter element located in functional proximity to the cathode and comprising a porous fibrous sheet material defining pores in a range of from about 0.1 to about 100 micrometers, with a portion of the fibers thereof being uniformly coated with a nonparticulate, elemental metal and a portion of the fibers thereof not being coated with a metal;
• and
• a means of establishing between the cathode and the anode filter element a nonalternating potential difference which is sufficient to maintain a corona field of ionized gas therebetween;
• in which
• the portion of the anode filter element of the first cathode-anode filter element pair having fibers not coated with a metal and the portion of the anode filter element of the second cathode-anode filter element pair having fibers not coated with a metal do not substantially coincide.

A corona-assisted electrostatic filtration apparatus for the removal of particulate matter from a gaseous medium, the apparatus comprising:

• a first cathode-anode filter element pair;
• and
• a second cathode-anode filter element pair;
• in which each of the first and second cathode-anode filter element pairs comprises:
• a cathode;
• an anode filter element located in functional proximity to the cathode and comprising a porous fibrous sheet material defining pores in a range of from about 0.1 to about 100 micrometers and having at least one aperture therethrough, with at least a portion of the fibers thereof being uniformly coated with a nonparticulate, elemental metal;
• and
• a means of establishing between the cathode and the anode filter element a nonalternating potential difference having a magnitude which is sufficient to maintain a corona field of ionized gas therebetween;
• in which
• the apertures in the anode filter element of the first cathode-anode filter element pair and the apertures in the anode filter element of the second cathode-anode filter element pair do not substantially coincide.

A method of removing particulate matter from a gaseous medium which comprises:

• moving the gaseous medium sequentially past a cathode and through an anode filter element;
• and
• establishing between the cathode and the anode filter element a nonalternating potential difference having a magnitude which is sufficient to maintain a corona field of ionized gas therebetween;
• in which:
• the cathode has a size, shape and location;
• the anode filter element is located in functional proximity to the cathode;
• the anode filter element comprises a porous fibrous sheet material defining pores in a range of from about 0.1 to about 100 micrometers, with at least a portion of the fibers thereof being uniformly coated with a nonparticulate, elemental metal;
• and
• the size, shape, and location of the cathode and the magnitude of the potential difference are selected to direct the particulate matter only to selected areas of the anode filter element, such that a portion of the anode filter element remains substantially free of particulate matter.

A method of removing particulate matter from a gaseous medium which comprises:

• moving the gaseous medium sequentially past a cathode and through an anode filter element of a first cathode-anode filter element pair and sequentially past a cathode and through an anode filter element of a second cathode-anode filter element pair;
• and
• establishing between the cathode and the anode filter element of each cathode-anode filter element pair a nonalternating potential difference having a magnitude which is sufficient to maintain a corona field of ionized gas therebetween;
• in which
• the cathode of each cathode-anode filter element pair has a size, shape and location;
• the anode filter element of each cathode-anode filter element pair is located in functional proximity to the cathode of each pair and comprises a porous fibrous sheet material defining pores in a range of from about 0.1 to about 100 micrometers, with at least a portion of the fibers thereof being uniformly coated with a nonparticulate, elemental metal;
• for each cathode-anode filter element pair, the size, shape, and location of the cathode and the magnitude of the potential difference are selected to direct the particulate matter only to selected areas of the anode filter element, such that a portion of the anode filter element remains substantially free of particulate matter;
• and
• the portion of the anode filter element of the first cathode-anode filter element pair which remains substantially free of particulate matter and the portion of the anode filter element of the second cathode-anode filter element pair which remains substantially free of particulate matter do not substantially coincide.

A method of removing particulate matter from a gaseous medium which comprises:

• moving the gaseous medium sequentially past a cathode and through an anode filter element of a first cathode-anode filter element pair and sequentially past a cathode and through an anode filter element of a second cathode-anode filter element pair;
• and
• establishing between the cathode and the anode filter element of each cathode-anode filter element pair a nonalternating potential difference having a magnitude which is sufficient to maintain a corona field of ionized gas therebetween;
• in which
• the anode filter element of each cathode-anode filter element pair is located in functional proximity to the cathode of each pair and comprises a porous fibrous sheet material defining pores in a range of from about 0.1 to about 100 micrometers, with a portion of the fibers thereof being uniformly coated with a nonparticulate, elemental metal and a portion of the fibers thereof not being coated with a metal;
• and
• the portion of the anode filter element of the first cathode-anode filter element pair having fibers not coated with a metal and the portion of the anode filter element of the second cathode-anode filter element pair having fibers not coated with a metal do not substantially coincide.

A method of removing particulate matter from a gaseous medium which comprises:

• moving the gaseous medium sequentially past a cathode and through an anode filter element of a first cathode-anode filter element pair and sequentially past a cathode and through an anode filter element of a second cathode-anode filter element pair;
• and
• establishing between the cathode and the anode filter element of each cathode-anode filter element pair a nonalternating potential difference having a magnitude which is sufficient to maintain a corona field of ionized gas;
• in which
• the anode filter element of each cathode-anode filter element pair is located in functional proximity to the cathode of each pair and comprises a porous fibrous sheet material defining pores in a range of from about 0.1 to about 100 micrometers and having at least one aperture therethrough, with at least a portion of the fibers thereof being uniformly coated with a nonparticulate, elemental metal;
• and
• the apertures in the anode filter element of the first cathode-anode filter element pair and the apertures in the anode filter element of the second cathode-anode filter element pair do not substantially coincide.