US 3828526 A
A particle collector, such as for installation within a heating duct for removing dust from the air flowing therethrough, is capable of corona-free operation to preclude the generation of ozone within the heating duct. The composite collector has inner and outer tubular electrodes separated by a dielectric casing with a dielectric sheathing around the outer electrode so that a charge is imparted to the sheathing for retention thereby to attract charged particulate matter. A series of the composite collectors charged alternately positive and negative may be utilized to remove both negatively and positively charged particulate matter from a fluid stream, and a spray wash system may be employed to periodically remove collected matter from the units.
Description (OCR text may contain errors)
United States Patent 1191 King  Aug. 13, 1974 1 PARTICLE COLLECTOR  Inventor: Arthur'S. King, 9013 W. 51st Ter.,
Merriam, Kans. 66203  Filed: Oct. 17, 1972  Appl. N0.: 298,310
 U.S.'C1..., 55/118, 55/136, 55/146, 55/155, 55/D1G. 38, 317/242  Int. Cl. B03c 3/06, B030 3/78  Field of Search 55/117, 118, 120, 146,
55/155, 136, DIG. 38; 317/242  References Cited UNITED STATES PATENTS 1,601,771 10/1926 Rowland 55/120 2,152,077 3/1939 Meston et al..' 317/242 X 2,451,338 10/1948 Heller 317/242 2,559,141 7/1951 Williams 317/242 X 2,706,742 4/1955 Ehlers 174/52 2,725,312 11/1955 Schell 117/218 2,769,944 ll/l956 Stein ct a1 339/275 X 2,958,393 11/1960 Lucder 55/155 3,001,267 9/1961 Heibel et a1. 29/1555 3,123,765 3/1964 Julie 323/74 3,449,094 6/1969 Baxt et a1 131/262 Primary Examiner-Dennis E. Talbert, Jr. Attorney, Agent, or Firm Schmidt, Johnson, Havey &. Williams [5 7] ABSTRACT A particle collector, such as for installation within a heating duct for removing dust from the air flowing therethrough, is capable of corona-free operation to preclude the generation of ozone within the heating duct. The composite collector has inner and outer tubular electrodes separated by a dielectric casing with a dielectric sheathing around the outer electrode so that a charge is imparted to the sheathing for retention thereby to attract charged particulate matter. A series of the composite collectors charged alternately positive and negative may be utilized to remove both negatively and positively charged particulate matter from a fluid stream, and a spray wash system may be employed to periodically remove collected matter from the units.
4 Claims, 3 Drawing Figures I 1 PARTICLE COLLECTOR This invention'relates to electrically charged equipment for removing particulate matter from a fluid and, more particularly, to corona-free collector apparatus which is especially well-suited, for removing dust and other dry particulate matter from a stream of gas, such as hot air flowing from furnaces.
Many types of electrified particle collectors heretofore available, especially dust collectors for home or business installations, have relied upon a corona discharge from one of the electrodes of the collector toward the other to attract particulate matter to the discharging electrode and to, in effect, burn up the particles coming within the influence of the corona. Collectors of this type have a very serious drawback where the gas being treated consists merely of ambient air in that the corona produces ozone, which is extremely toxic. Thus, systems which rely upon a corona discharge must be carefully regulated to avoid the generation of ozone beyond a predetermined level of safety, and persons living and working within the ozone-laden atmosphere must be careful to limit their exposure to the noxious atmosphere.
Accordingly, an important object of the present invention is to provide a safe, effective, corona-free particle collector which is ideally suited for removing dust from the airstreams of heating, cooling and ventilating systems in view of the complete absence of ozone generated by the collector.
Another important object of this invention is the provision of a particlecollector as aforesaid which comprises a single composite unit capable of producing an electrostatic field within itself to present a charged, exposed outer surface to attract particulate matter without corona discharged.
As a corollary to the'foregoing object, it is an important aim of this invention to provide a composite collector unit having inner and outer, oppositely charged electrodes separated by a dielectric material to prevent current flow, yet establish an electrostatic field, the outer electrode of the unit having a second dielectric sheathing thereabout for holding a charge imparted thereto by the outer electrode, yet precluding current flow from the latter to any conductive environmental surfaces.
A further important object of this invention is the provision of spray means associated with the particle collector for periodically washing collected matter therefrom.
In the drawing:
FIG. 1 is a vertical cross-sectional view of a particle collector constructed in accordance with the teachings of my present invention;
FIG. 2 is a horizontal cross-sectional view of the collector taken along line 22 of FIG. 1; and
FIG. 3 is a fragmentary, cross-sectional view on a re duced scale of a dust-collecting installation employing two or more of the collectors illustrated in FIGS. 1 and 2.
The collector unit 10 has an inner electrode 12 which may be tubular in configuration as illustrated in FIGS. 1 and 2, or may be a solid rod without impairing the principles of the present invention. A first dielectric casing 14 surrounds inner electrode 12 and is thus positioned between the latter and an outer electrode 16 which may take the form of a metal foil layered upon dielectric l4. Surrounding outer electrode 16 is a second dielectric sheathing 18 which is constructed from a material such as Teflon. The important property with regard to sheathing 18 is that while it must electrically insulate outer electrode 16 to prevent current flow from the latter to conductive environmental surfaces, sheathing 18 must still be capable of holding an electric charge imparted thereto by outer electrode l6.
A pair of conductors 20 and 22 are electrically secured to the inner and outer electrodes 12 and 16 respectively for connecting the same across a source of electrical potentialto charge unit 10. Insulating closure elements 24 at opposite ends of unit 10 seal the latter against moisture and prevent short-circuiting of unit 10 should the latter come into contact with an environmental surface at ground potential.
Because dielectric casing 14 is interposed between electrodes 12 and 16, electrical current flow between electrodes 12 and 16 is effectively precluded. However, an electrostatic field is established with electrodes 12 and 16 retaining their opposite polarities so that sheathing 18 takes on and retains a charge imparted thereto by outer electrode 16. Therefore, when unit 10 is placed within a stream of fluid containing particulate matter, such as dust-laden air within heating ducts or conduits, the particles which carry a charge opposite in polarity to that of sheathing 18 are attracted to the latter and collect thereon as the stream flows past the unit 10.
Such removal of charged particulate matter from a flowing stream of gas or liquid is thus accomplished entirely without corona discharge and its attendant ozone generation (in gas streams where oxygen is present By virtue of the fact that no current flow is produced between electrodes 12 and 16, nor between electrode 16 and any conductive environmental surface, only an electrostatic field is created, completely precluding the possibility of ozone generation.
FIG. 3 illustrates an installation utilizing more than one unit 10 so that charged particles of different polarities may be removed from a fluid medium. In this regard, a duct or conduit 26, such as for carrying heated air from a furnace to a remote point, has a pair of the units 10 housed therewithin, each unit 10 being inserted into and removed from conduit 26 through an opening 28 which is normally closed by a cover 30 secured in place by a pair of sheet metal screws 32. A pair of sealing assemblies 34 are provided at opposite ends of each unit 10 to prevent the entry of moisture into the interior .of the respective units 10 from the outer surface of sheathing l8, and each assembly 34 comprises a pair of threadably interlocking components 36 and 38 which are slipped onto sheathing l8 and clamp an O- ring 40 between themselves to force the ring 40 into tight sealing engagement with sheathing 18. The endmost component 36 of each assembly 34 projects slightly through the proximal opening 28, and each cover 30 is formed to complementally receive its corresponding end component 36 to locate and hold the unit 10 in place. An upstanding locating ring 42 on the floor of conduit 26 for each unit 10 receives the corresponding component 36 at the normally lower end of each unit 10 to cooperate with its formed cover 30 in retaining the unit 10.
Preferably, units 10 are offset from one another within conduit 26 so that gas flowing therethrough may pass in close proximity to both units,it being understood that a multitude of units could be utilized within conduit 26, depending upon its size, in order to completely remove the particulate matter flowing therethrough.
By reversing the connections of the conductors and 22 of certain of the units 10 with the source of electrical potential, alternate units 10 in the group may be positively and negatively charged so that negatively charged particles are attracted to the positively charged units 10, while positively charged particles are attracted to the negatively charged units 10. In this manner, virtually all of the charged particulate matter within the stream flowing through conduit 26 may be effectively and safely removed.
In order to provide periodic cleaning of the units 10, conduit 26 is provided with a spray nozzle 44 for each unit 10, operable to direct a stream of cleaning liquid onto the sheathing 18 of the respective units 10, thus washing the collected matter therefrom for reception within a basin defined by opposed members 46 and 48. A drain 50 is provided within the basin thus defined to allow periodic emptying of the slurry from conduit 26.
Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:
1. In combination with conduit means normally carrying a gas containing particulate matter, corona-free collecting apparatus for removing the matter 'from the gas including:
a plurality of spaced-apart, individually operable,
composite electrode units located within said conduit means, each being capable of producing its own electrostatic field independently of other units,
said units each having a pair of oppositely'charged electrodes separated by a first dielectric to establish an electrostatic field between said electrodes and prevent current flow, and a second dielectric on one of the electrodes exposed to the gas for holding a charge imparted to the second dielectric by said one electrode to attract particles opposite in polarity to the second dielectric,
alternate units having their second dielectrics oppositely charged whereby particles of one polarity are attracted to one of the units while those of the opposite polarity are attracted to the next unit; and
cleaning means within said conduit means for periodically removing collected particles from the second dielectrics of said units.
2. Collecting apparatus as claimed in claim 1,
wherein said cleaning means includes sprayer means for directing liquid to said second dielectrics of the units to wash the same.
3. Collecting apparatus as claimed in claim I, wherein said one electrode of each unit is tubular in configuration, surrounding the other electrode and the first dielectric.
4. Collecting apparatus as claimed in claim 3, wherein said second dielectric of each unit surrounds said one electrode.