Electrostatic air filter

Claim 2

An electrostatic air filter comprising in combination: a filter unit having a first relatively thin layer of dielectric filter media, a second relatively thin layer of dielectric filter media disposed in close proximity to the first layer, electrode means including a fine wire grid interposed between and in close proximity with the first and second filter media, a pair of spaced conductive and chargeable surfaces on opposed sides of the dielectric layers away from the grid, a power pack for supplying a relatively high voltage at relatively low amperage to the filter unit, electrically conductive means for coupling the power pack to the filter unit, the positive side of said power pack being connected to said fine wire grid and the negative side of said power pack being connected to said chargeable surfaces whereby an imposed electrostatic high-voltage ionizing field across the filter causes ions to flow through the filter media and bombard very fine air-borne particles and simultaneously cause their precipitation out onto the media, and means for securing as an assembly the layers, interposed grid and chargeable surfaces.

Claim 3

The invention in accordance with claim 1 wherein the filter media is selected from the group consisting of polyester fibers and an open cell plastic foam filter material.

Claim 4

An electrostatic air filter comprising in combination: a filter unit having at least one relatively thin layer of dielectric filter media, conductive means including a fine wire grid in close proximity with the first filter media, a spaced conductive and chargeable surface on the opposite side of one of the filter media away from the grid, a power pack for supplying a relatively high voltage at relatively low amperage to the filter unit, electrically conductive means for coupling the power pack to the filter unit, the positive side of said power pack being connected to said fine wire grid and the negative side of said power pack being connected to said chargeable surface for cooperating in imposing an electrostatic high voltage ionizing field across the filter causing ions to flow through the filter media and bombard very fine air-borne particles and simultaneously cause their precipitation out onto the media, a pre-filter means disposed in close proximity to one of the filter media and at the inlet side of the filter unit for filtering air passing through the pre-filter and removing air-borne large dust particles and lint, and means for securing as an assembly the layer, chargeable surface, grid and pre-filter.

Claim 5

An electrostatic air filter comprising in combination: a filter unit having at least one relatively thin layer of dielectric filter media, conductive means including a fine wire grid in close proximity with the first filter media, a spaced conductive and chargeable surface on the opposite side of one of the filter media away from the grid, a power pack for supplying a relatively high voltage at relatively low amperage to the filter unit, electrically conductive means for coupling the power pack to the filter unit, the positive side of said power pack being connected to said fine wire grid and the negative side of said power pack being connected to said chargeable surface for cooperating in imposing an electrostatic high voltage ionizing field across the filter causing ions to flow through the filter media and bombard very fine air-borne particles and simultaneously cause their precipitation out onto the media, a pre-filter means disposed in close proximity to one of the filter media and at the inlet side of the filter unit for filtering air passing through the pre-filter and removing air-borne large dust particles and lint, and means for securing as an assembly the layer, chargeable surface, grid and pre-filter.

Claim 6

The invention in accordance with claim 3 wherein a second relatively thin layer of dielectric filter media is disposed in close proximity to the first layer and the conductive means is interposed and in close proximity with the first and second filter media.

Claim 7

The invention in accordance with claim 4 wherein the pre-filter is conductive.

Claim 8

The invention in accordance with claim 4 wherein the prefilter is formed of expanded aluminum foil.

Claim 9

The invention in accordance with claim 4 wherein the prefilter and filter unit are positioned relative to one another by means of a peripherally extending frame.

Claim 10

The invention in accordance with claim 4 wherein the prefilter is aluminum foil approximately one-half inch thick and each of the filter media is of polyester fiber and is one-fourth inch thick and the grid is formed from a single layer of 8 mesh screen wire.

Claim 11

The invention in accordance with claim 4 wherein the electrostatic filter unit is adapted to remove at least 90 percent of the particles 1 micron and larger from the airstream.

Claim 12

The invention in accordance with claim 4 wherein a pair of electrically conductive perforated plates are spaced from one another and have interposed therebetween the prefilter and filter unit.

Claim 13

The invention in accordance with claim 10 wherein a non-conductive header is disposed about the periphery of the prefilter and filter unit and between the conductive perforated plates to dispose and position the prefilter and filter unit in a predetermined relationship between the perforated plates.

Claim 14

The invention in accordance with claim 11 wherein means are provided for electrically coupling the spaced screens and grid to a relatively high-voltage low-amperage power source and imposing upon the plates a negative charge and the grid a positive charge whereupon ions are adapted to flow from the front plate through the electrically conductive prefilter through one layer of dielectric filter media to the positive grid and ions adapted to flow from the rear plate to the adjacent dielectric filter material to the positive grid, the ions adapted to bombard the air-borne particles of the airstream being filtered causing the particles to precipitate out on to the filter media.

Claim 15

The invention in accordance with claim 12 wherein the power source is adapted to supply voltage between 2,500 volts and 3,500 volts.

Claim 16

The invention in accordance with claim 13 wherein the power source supplies 3,000 volts D. C.

Claim 17

The invention in accordance with claim 10 wherein the front screen has larger openings than the back screen and the openings of the front screen are approximately 3/4 inch squares and the openings in the rear screen are approximately 1/4 inch squares.