US 3826063 A
An electrostatic agglomeration apparatus for an air filtering and conditioning system, comprising an air duct having a pair of channels disposed either within the duct or adjacent thereto and opening into the duct at both ends. A plurality of electrically conductive rods are disposed in the channels and are charged electrically positive in one channel and negative in the other channel so that particulate matter flowing into the channels is ionized by the charges on the electrical rods and agglomerates to form larger particulate masses which are more easily filterable from the air flowing through the system.
Claims available in
Description (OCR text may contain errors)
ilitite States Festner ateitt [1 1 1 3,826,063 [4 1 July 30, 1974 1 ELECTROSTATIC AGGLOMERATION APPARATUS  Inventor: Theodor Festner, 16 Ridge Rd,
Upper Saddle River, NJ. 07458  Filed: May 21, 1973  Appl. N0.: 362,141
 US. Cl 55/128, 55/73, 55/122, 55/124, 55/136, 55/151, 55/152, 55/D1G. 25, 55/D1G. 29  Int. Cl. B03c 3/00 8] Field of Search 55/129, 103, 106, 107,
55/124, 125, 126,128,130, 133, 136, 137, 138,139, 148, 150, 151, 152, DIG. 25, DIG.
 References Cited UNITED STATES PATENTS 1,357,466 11/l920 Moller 55/138 X 1,472,231 10/1923 Schmidt 55/129 X 2,173,802 9/1939 Downs et a l. 55/122 UX 2,318,093 5/1943 Penney 55/134 2,634,818 4/1953 Wintcrmute 55/136 X 2,694,464 11/1954 Wintermute 55/152 Prentiss... 55/133 X Baruch 99/71 3,091,069 5/1963 Brasefield 55/103 X 3,350,850 11/1967 Stcvernagcl 1 55/148 3,503,704 3/1970 Marks 55/5 FOREIGN PATENTS OR APPLICATIONS 19,733 1913 Great Britain 55/152 846,522 8/1960 Great Britain 55/138 882,803 1 [/1961 Great Britain 55/151 45-28480 9/1970 Japan 55/136 Primary ExaminerDennis E. Talbert, Jr. Attorney, Agent, or Firm-Allison C. Collard 5 7] ABSTRACT An electrostatic agglomeration apparatus for an air filtering and conditioning system, comprising an air duct having a pair of channels disposed either within the duct or adjacent thereto and opening into the duct at both ends. A plurality of electrically conductive rods are disposed in the channels and are charged electrically positive in one channel and negative in the other channel so that particulate matter flowing into the channels is ionized by the charges on the electrical rods and agglomerates to form larger particulate masses which are more easily filterable from the air flowing through the system.
3 Claims, 6 Drawing Figures Pmmznwwmw 3.826.063
SHEET 2 OF 2 Ila ELECTROSTATIC AGGLOMERATION APPARATUS The present invention relates to electrostatic precipitators, and in particular to an electrostatic agglomeration apparatus for agglomerating particulate matter suspended in and carried by gases for improving the filtering efficiency of filtering equipment.
Many industrial, scientific and medical procedures require that the environment worked in be absolutely free of foreign particles. Conventional air conditioning and environmental control systems utilized to provide such clean rooms, however, utilize filtering equipment which is generally not capable of filtering extremely small particulate matter from the air circulated through the system. As a result, such systems have limited filtering ability with respect to the size of the particles filtered from the system, and the rooms whose air is cleaned by the system is accordingly sterilized only to a limited extent.
Accordingly, the present invention provides an electrostatic agglomeration apparatus for an air filtering and conditioning system which overcomes the abovementioned disadvantages of conventional air conditioning and environmental control systems. The agglomeration apparatus comprises, in one embodiment, an elongated air duct having a pair of bypass channels on each side opening into the duct at both ends. A plurality of electrically-conductive rods are disposed longitudinally in the channels and are charged electrically positively on one side of the duct and negatively on the other side of the duct. Particulate matter flowing into the channels is ionized by the charges on the electrical rods so that it is either positively or negatively charged. When the particulate matter re-enters the duct, oppositely charged particles agglomerate to form a larger particulate mass which is more easily filterable from the air by a filtering system.
In another embodiment of the invention, the interior of the duct is divided in a predetermined proportion into two compartments. Electrically conductive rods are disposed downwardly into the compartments and are charged electrically positive in one compartment and negative in the other compartment. Particulate matter flows through the duct in either one of the compartments and the particles are ionized accordingly. Upon leaving the compartments, the particulate matter agglomerates.
In still another embodiment of the invention, a bypass channel is integrally formed with and disposed adjacent a duct, and is divided into two compartments for charging particles either electrically positive or negative.
It is, therefore, an object of the present invention to provide an electrostatic agglomeration apparatus for improving the filtering efficiency of an air filtering system.
It is another object of the present invention to provide an electrostatic agglomeration apparatus for agglomerating particulate matter which is simple in design, easy to manufacture, and efficient and reliable in operation.
Other objects and features of the present invention will become apparent from the following detailed description when taken in connection with the accompanying drawings which disclose several embodiments of the invention. It is to be understood, however, that the drawings are designed for the purposes of illustration only, and are not intended as a definition of the limits and scope of the invention.
In the drawings, wherein similar reference numerals denote similar elements throughout the several views:
FIG. 1 is a perspective view of one embodiment of an electrostatic agglomeration apparatus constructed in accordance with the present invention;
FIG. 2 is a top cross-sectional view of the apparatus, taken along section 22 of FIG. 1;
FIG. 3 is a top planar view of a plurality of electrostatic agglomeration units coupled together in a duct system.
FIG. 4 is another embodiment of the present invention in perspective, partially broken, revealing arrangement of electrostatic conductors and means for washing the gases;
FIG. 5 is a cross-sectional end view of the apparatus, taken along section 55 of FIG. 4; and
FIG. 6 is a partial perspective view of another embodiment of an electrostatic agglomeration apparatus constructed in accordance with the present invention.
Referring to the drawings, specifically FIGS. l3, there is shown an electrostatic agglomeration apparatus, generally denoted as 10, comprising an elongated rectangular-shaped metallic air duct 11 having a plurality of cylindrically shaped bypass channels 12 integrally formed therewith and opening into duct 11 at each end thereof. A plurality of cylindrically shaped electrically conductive rods 13 are disposed in the bypass channels parallel to the longitudinal axis thereof, and are secured at one end in electrically non-conductive insulators 14 disposed in one end of the bypass channels. Duct 11 has a pair of air flaps l5 integrally formed therewith disposed adjacent the opening of the bypass channels into the duct. When a plurality of ducts 11 are coupled together in a cascaded arrangement, they are preferably separated by a conventional rectangularshaped air duct 16 which serves as a particle agglomeration zone.
In operation, air flowing through the duct system enters duct 11 at its entrance opening 17 and is channeled into bypass channels 12 by flaps 15. Some of the air, however, flows directly through duct 11. The air flowing into the bypass channels has the particulate matter suspended therein ionized by the high voltage electrical charges provided on rods 13. These rods are connected to a high voltage power supply of approximately 10-40kv. The particulate matter in one set of bypass channels is, thus, charged positively, and that in the other set of channels negatively. When the air exits from outlet openings 18, thus, the oppositely charged particles are attracted towards each other and agglomerate to form a mass larger than the individual particles. A plurality of agglomeration units are preferably provided in an air conditioning or environmental control system so that the particles are continuously agglomerated to form masses of progressively larger sizes. The greater the agglomeration of the particles, the greater the efficiency of the filtering apparatus of the system.
Another embodiment of the invention is illustrated in FIGS. 4 and 5. In this embodiment, duct 11 is divided into two compartments by a divider panel 19. A pair of high-voltage discharge frames 20, having a plurality of needle-like discharge members 30 extending outwardly therefrom, are disposed in each of the compartments formed by divider l9 and are coupled to external terminals mounted in insulators 22. Discharge frames 20 extend downwardly into the compartments, and electrically conductive ground strips 23 extend upwardly between the frames in the compartment. Terminals 21 are coupled to a high-voltage power source, of approximately 10,000, 20,000 or 40,000 volts depending on electrode spacing. The. terminals of each compartment are charged with voltages of opposite polarity so that positive and negative ionization coronas are created by electron leakage between the discharge frame and strips 23, and particles flowing through one compartment are ionized by the positive electrical charge and particles flowing through the other compartment are ionized by the negative electrical charge. After the air passes through both compartments, the particles of opposite polarity agglomerate as described above. One or more ducts 11' may be utilized in a cascaded arrangement in an air conditioning or environmental control system,
Duct 11' contains a plurality of spray means 11a for injecting a water spray (not shown) into the compartments. The water spray will wash with the effluent gases and substantially absorb those that are water soluable. The water falls through the compartment and collects at egress means 11b, more clearly seen in FIG. 5. It is apparent that the water leaving means 11b will now contain those gases capable of being absorbed therein. For example, if the compartment contains sulfer dioxide (S0,) it will form a weak acid with the water spray. The resulting mixture will leave by means of discharge 1112 instead of being expelled to the atmosphere.
FIG. 6 illustrates still another embodiment of a electrostatic agglomeration apparatus. Duct 11" has a centrally divided bypass channel 24 disposed on the outside surface and opening into the interior of the duct at its intake opening 25. A movable flap 26 controls the amount of air channeled into the bypass channel. The first half of each U-shaped portion of the bypass channel is provided with a dividing panel 27 which divides them into two compartments. Electrically conductive cylindrical rods 28 are downwardly disposed in the compartments on each side of the dividing panels and are charged with electrical voltages of opposite polarity. The particulate matter in the air flowing through the compartments is ionized as described previously, and agglomerates as the air flows downwardly in portions 29 of the bypass channels. The arrangement, thus, provides a cascaded series of agglomeration devices bypassing ducts 11".
The gas flow through any of the ducts of the previously described embodiments may be adjusted so that it is any desired or required proportion, such as 50/50. The materials used to construct the apparatus of the present invention may be any suitable type, and their selection presents no problem to those persons skilled in the art.
While only several embodiments of the present invention have been shown and described, it will be obvious to those persons of ordinary skill in the art that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
What is claimed is:
1. An electrostatic agglomeration apparatus, comprising:
an air duct;
a bypass channel, disposed adjacent to and opening at each end into said air duct, and including at least one U-shaped section disposed perpendicular to the longitudinal axis of said air duct, and at least one planar rigid member disposed in said U-shaped section for dividing at least one half of said U- shaped section into two compartments for separating the air flowing through said bypass channel; and
a plurality of electrically oppositely charged conductive rods disposed in said compartments for ionizing individual particles of particulate matter therein, said particulate matter in one of said compartments being charged electrically positive and matter in the other compartment being charged electrically negative, whereby said positively and negatively charged matter agglomerates upon flowing from said compartments into the other half of said U-shaped section of said bypass channel into masses of particulate matter of larger size than the individual particles of said matter.
2. The apparatus as recited in claim 1, wherein said rods comprise a plurality of elongated cylindrical rods disposed longitudinally in said compartments.
3. The apparatus as recited in claim 2, further comprising an adjustable flap, pivotably mounted in said air duct, for adjusting the flow of air into said bypass channel.