Electrostatic gas filters

Claim 2

An electrostatic gas filter element to be positioned upstream of a collector element comprising: a duct; three planar electrode means in said duct, said electrode means being perpendicular to the axis from said duct and spaced from each other, whereby a first electrode means is disposed between the other two electrode means, each of said electrode means comprising a frame including two spaced and parallel bars of conducting material, and a length of braided multi-wire metallic conductor connected to said parallel bars to form an array of parallel conductors extending between said bars, the parallel conductors of said first electrode means being positioned with respect to the parallel conductors of at least one other of the planar electrode means so as to be mutually offset with respect to the axis of said duct; means for applying a first voltage which sinusoidally varies about ground potential to said said first electrode means; and means for applying a second pulsating voltage which is unidirectional with respect to ground potential with a portion of its waveform having an A.C. ripple to both of said other two electrode means.

Claim 3

The electrostatic gas filter element of claim 1 wherein each of said two spaced and parallel bars carry a plurality of spacers and said length of multiwire metallic conductor is alternately and regularly wrapped in gaps between said spacers and extending across the space between said bars.

Claim 4

The electrostatic gas filter element of claim 1 wherein said second voltage has an amplitude in the kilovolt range.

Claim 5

The electrostatic gas filter element of claim 1 wherein the wires of said metalliC conductor are braided according to a diamond pattern.

Claim 6

An electrostatic gas filter element to be positioned upstream of a collector element comprising: a duct; three planar electrode means in said duct, said electrode means being perpendicular to the axis from said duct and spaced from each other, whereby a first electrode means is disposed between the other two electrode means, each of said electrode means comprising a frame including two spaced and parallel bars of conducting material, a plurality of conductor engaging means fixed at regular intervals along said bars, a length of braided wire conductor laced on said engaging means to form an array of parallel conductors extending between said bars, the engaging means of the frame of said first electrode means being positioned with respect to the engaging means of the frame of at least one other of the planar electrode means so that their respective conductors are mutually offset with respect to the axis of said duct; means for applying a first voltage which sinusoidally varies about ground potential to said said first electrode means; and means for applying a second voltage which is unidirectional with respect to ground potential and has a substantially sawtooth waveform with a portion thereof having an A.C. ripple to both of said other two electrode means.

Claim 7

An electrostatic gas filter element to be positioned upstream of a collector element comprising: a duct; three planar electrode means in said duct, said electrode means being perpendicular to the axis from said duct and spaced from each other, whereby a first electrode means is disposed between the other two electrode means, each of said electrode means comprising a frame including two spaced and parallel bars of conducting material, a plurality of conductor engaging means fixed at regular intervals along said bars, a length of braided wire conductor laced on said engaging means to form an array of parallel conductors extending between said bars, the engaging means of the frame of said first electrode means being positioned with respect to the engaging means of the frame of at least one other of the planar electrode means so that their respective conductors are mutually offset with respect to the axis of said duct; means for applying a first voltage which sinusoidally varies about ground potential to said said first electrode means; and means for applying a second voltage which is unidirectional with respect to ground potential and has a substantially sawtooth waveform with a portion thereof having an A.C. ripple to both of said other two electrode means.