Method and apparatus for electrostatic removal of particulate from a gas stream

Claim 2

Apparatus for removing particulate matter from a gas stream comprising: a housing having inlet and outlet ends and wall means defining a horizontal gas flow path between said ends, said housing being of generally uniform cross-sectional dimension between said ends, horizontally spaced apart grid means in said housing between said ends and defining a contact chamber with said wall means, said contact chamber containing only randomly oriented packing elements of dielectric material, said elements together occupying the space between said wall means and grid means and defining a porous mass having a horizontal top surface, irrigating liquid discharge means in said housing overlying said top surface for distributing irrigating liquid across Said surface for flow by gravity downwardly through said contact chamber and through and in contact with said packing elements, a sump beneath said contact chamber to receive irrigating liquid flowing through said contact chamber, a pump for recirculating irrigating liquid from said sump to said discharge means, a plurality of generally parallel electrodes in said housing providing a particle charging section between said inlet end and said contact chamber, said electrodes being spaced apart transverse to the direction of gas flow through said housing, first alternate ones of said electrodes being wires connected to a source of direct current and second alternate ones of said electrodes being connected to ground, means to flow liquid onto said electrodes to clean the electrodes, means electrically grounding said housing to maintain said irrigating liquid and packing elements electrically neutral, and means causing said gas to flow past said electrodes and thence through said contact chamber transverse to the direction of irrigating liquid flow therethrough.

Claim 3

Apparatus according to claim 1, and second liquid distribution means between said electrodes and the adjacent one of said grid means for directing liquid onto said adjacent grid means, and conduit means connecting said second liquid distribution means with said sump and said pump for said pump to circulate liquid from said sump to said second distribution means.

Claim 4

Apparatus for removing particulate matter from a gas stream comprising, a generally horizontal housing open at its opposite ends and having top, bottom and sidewalls between said opposite ends, grid means within said housing and horizontally spaced apart between said opposite ends, said top, bottom and sidewalls and said grid means together defining a contact chamber in said housing, a gas inlet duct at one of said opposite ends, a gas outlet duct at the other of said opposite ends, randomly oriented packing elements substantially filling said contact chamber, each of said packing elements being generally toroidal and defined by filamentous dielectric material, said packing elements in said contact chamber together providing a porous mass having a top surface spaced beneath said top wall, baffle plates extending between said sidewalls and between said top wall and said top surface of said packing elements to restrain gas flow across said contact chamber in the space between said top wall and top surface, irrigating liquid conduit means including a plurality of liquid outlets between said baffle plates and overlying said top surface of said packing elements for distributing irrigating liquid across said surface for flow by gravity downwardly through said contact chamber and through and in contact with said packing elements, said irrigating liquid conduit means further including liquid outlets for directing liquid onto the one of said grid means facing said inlet duct, a sump beneath said bottom wall and in liquid flow communication with said contact chamber to receive irrigating liquid flowing downwardly through said contact chamber, a pump for pumping irrigating liquid in said sump to said conduit means, a plurality of generally parallel electrodes in said inlet duct, first alternate ones of said electrodes being wires connected to a source of direct current and second alternate ones of said electrodes being connected to ground, said wires being in a common plane extending transversely across said inlet duct, means to flow liquid on said electrodes to clean the electrodes, means electrically grounding said housing to maintain said irrigating liquid and packing elements electrically neutral, said pump and irrigating liquid outlets providing for liquid flow downwardly through said packing elements at a rate of from 1,000 to 12,000 pounds per hour per square foot of the area of said top surface of said porous mass, and means causing said stream of gas to flow past said electrodes and thence across said contact chamber transverse to said direction of Liquid flow and at a velocity of from 1 to 10 feet per second, whereby particles in said gas stream are electrically charged in passing said electrodes and charged particles are removed from said gas stream by attraction to said neutral irrigating liquid and packing elements when said charged particles approach said neutral liquid and packing elements in such close proximity thereto that the force of attraction therebetween overcomes the velocity of a particle and the drag force of said air stream thereon.

Claim 5

Apparatus for removing particulate matter from a gas stream comprising, a generally horizontal housing open at its opposite ends and having top, bottom and sidewalls between said opposite ends, grid means within said housing and horizontally spaced apart between said opposite ends, said top, bottom and sidewalls and said grid means together defining a contact chamber in said housing, a gas inlet duct at one of said opposite ends, a gas outlet duct at the other of said opposite ends, randomly oriented packing elements substantially filling said contact chamber, each of said packing elements being generally toroidal and defined by filamentous dielectric material, said packing elements in said contact chamber together providing a porous mass having a top surface spaced beneath said top wall, baffle plates extending between said sidewalls and between said top wall and said top surface of said packing elements to restrain gas flow across said contact chamber in the space between said top wall and top surface, irrigating liquid conduit means including a plurality of liquid outlets between said baffle plates and overlying said top surface of said packing elements for distributing irrigating liquid across said surface for flow by gravity downwardly through said contact chamber and through and in contact with said packing elements, said irrigating liquid conduit means further including liquid outlets for directing liquid onto the one of said grid means facing said inlet duct, a sump beneath said bottom wall and in liquid flow communication with said contact chamber to receive irrigating liquid flowing downwardly through said contact chamber, a pump for pumping irrigating liquid in said sump to said conduit means, a plurality of generally parallel electrodes in said inlet duct, first alternate ones of said electrodes being wires connected to a source of direct current and second alternate ones of said electrodes being connected to ground, said wires being in a common plane extending transversely across said inlet duct, means to flow liquid on said electrodes to clean the electrodes, means electrically grounding said housing to maintain said irrigating liquid and packing elements electrically neutral, said pump and irrigating liquid outlets providing for liquid flow downwardly through said packing elements at a rate of from 1,000 to 12,000 pounds per hour per square foot of the area of said top surface of said porous mass, and means causing said stream of gas to flow past said electrodes and thence across said contact chamber transverse to said direction of Liquid flow and at a velocity of from 1 to 10 feet per second, whereby particles in said gas stream are electrically charged in passing said electrodes and charged particles are removed from said gas stream by attraction to said neutral irrigating liquid and packing elements when said charged particles approach said neutral liquid and packing elements in such close proximity thereto that the force of attraction therebetween overcomes the velocity of a particle and the drag force of said air stream thereon.