Ion filtration air cleaner

Abstract

An ion filtration air cleaning device for cleaning air by use of electrostatic ion attraction. Air having suspended particles is drawn into the device through an inlet by a fan. An ionization source near the inlet generates ions. Electrical charge transfers from the ions to the suspended particles. The fan pushes the air and suspended charged particles toward an outlet. A filter located adjacent to the outlet operates by electrostatic attraction and filters the charged particles from the air, allowing cleansed air to be released from the device, with a reduced level of charged particle emission.

Claims

1. An air filtration device comprising: a housing; a fan positioned to create an airflow within the housing; a prefilter disposed within the housing; an ionizer disposed within the housing downstream from the prefilter and upstream from the fan; an electrostatically charged main filter disposed within the housing downstream from each of the ionizer and the fan; and a serpentine pathway or baffles separate from the ionizer and main filter are disposed between the ionizer and the main filter, through which the airflow passes before entering the main filter, the airflow passing from the fan through the serpentine pathway or baffles to increase mixing of the airflow before sending the airflow to the main filter.

2. The air filtration device of claim 1 wherein the fan is disposed within the housing.

3. The air filtration device of claim 1 wherein the fan is disposed upstream of the serpentine pathway or baffles.

4. The air filtration device of claim 1 wherein the electrostatically charged main filter comprises at least one electrically charged collection plate.

5. The air filtration device of claim 1 wherein the ionizer comprises a primary corona discharge emitter and a secondary corona discharge emitter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various aspects and embodiments disclosed herein will be better understood when read in conjunction with the appended drawings, wherein like reference numerals refer to like components. For the purposes of illustrating aspects of the present application, there are shown in the drawings certain preferred embodiments. It should be understood, however, that the application is not limited to the precise arrangement, structures, features, embodiments, aspects, and devices shown, and the arrangements, structures, features, embodiments, aspects and devices shown may be used singularly or in combination with other arrangements, structures, features, embodiments, aspects and devices. The drawings are not necessarily drawn to scale and are not in any way intended to limit the scope of this invention, but are merely presented to clarify illustrated embodiments of the invention. In these drawings:

(2) FIG. 1 is functional schematic view of a conventional electrostatic air cleaner apparatus as known in the art.

(3) FIG. 2 is a functional schematic view of an electrostatic air cleaner apparatus according to an embodiment of the present invention.

(4) FIG. 3 is a functional schematic view of an electrostatic air cleaner apparatus according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) Embodiments of the present invention generally relate to the field of air cleaning systems. More specifically, embodiments relate to an ion filtration device (“IFD”) for cleaning air by use of electrostatic ion attraction.

(6) Referring to FIG. 1, a functional schematic of a conventional IFD 100 is illustrated. Within housing 111, fan 104 creates an airflow 110 within IFD 100 such that air is drawn into IFD 100 through an inlet 101 and passes first through a prefilter 102. Prefilter 102 removes large dust particles and fibers. Airflow 110 next passes through main filter 103, which is electrostatically charged to attract the incoming particles which carry the opposite charge from that of main filter 103. When IFD 100 is first turned on, it is expected that there will be few or no such charged particles in the confined space that IFD 100 is operating, therefore at first main filter 103 will not be very effective in removing charged particles.

(7) Next, fan 104 pushes airflow 110 past ionizer 105 which releases charged ions (not shown in FIG. 1) that enter airflow 110 and exit IFD through outlet 106. Air expelled from outlet 106 may disperse in substantially any direction, as indicated by exemplary directions 107, 108 and 109. As the air expelled from outlet 106 disperses throughout the space surrounding IFD 100, ions may transfer charge to suspended particles in the space surrounding IFD 100. A portion of the ions and/or charged particles eventually make their way back to inlet 101, such as along exemplary path 109.

(8) It can be seen that conventional IFD 100 is not efficient, at least for the following reasons. First, main filter 103 is not fully effective until charged particles pass through it. Second, because there is no control over the direction of air and ions that are expelled through outlet 106, only a fraction may reach their way back to the inlet 101, and the flow from outlet 106 to inlet 101 may be entirely blocked by drafts and air currents exterior to IFD 100. Third, charged particles may adhere to other surfaces in the space surrounding IFD 100, thereby causing an unwanted buildup of particles in unwanted locations. Fourth, because there may be a significant time delay between ionization and the entry of particles charged by those ions into inlet 101, the strength of the electrostatic charge may decay, causing reduced efficiency of main filter 103.

(9) FIG. 2 is a functional schematic of an improved IFD 200 according to an embodiment of the invention. In this embodiment, a structural difference compared to conventional IFD 100 is that a main filter 203, which is electrostatically charged to attract the incoming particles carrying the opposite charge from that of main filter 203, is located in airflow 210 downwind or downstream from an ionizer 205.

(10) In operation of IFD 200, within a housing 211 a fan 204 creates an airflow 210 within IFD 200 such that air is drawn into IFD 200 through an inlet 201 and passes first through a prefilter 202. Prefilter 202 removes large dust particles and fibers. Airflow 210 next passes adjacent to ionizer 205, which creates ions (not shown in FIG. 2). Charge from the ions may then be transferred to any suspended particles that had passed through prefilter 202.

(11) Next, fan 204 pushes airflow 210 through main filter 203, which attracts the incoming particles that carry the opposite charge from that of the ions. Finally, airflow 210 exits from IFD 200 through outlet 206.

(12) The embodiment of FIG. 2 may have a longer internal path for airflow 210 than the internal path for airflow 110 of a conventional IFD. The longer internal path allows for more effective mixing of ions with air, and provides a longer time for any particles suspended in airflow 210 to become charged. The longer path for airflow 210 is achieved by moving the main filter 203 to be near outlet 206, and by placing the ionizer 205 just after prefilter 202. This lengthens the path of airflow 210 between ionizer 205 and main filter 203, allowing the particles in the air more time to become charged, and thus removing the suspended particles more effectively from the airflow 210 by main filter 203. The air cleansed by main filter 203 will leave the improved IFD 200 in a relatively uncharged condition.

(13) The operation of improved IFD 200 is more efficient than that of conventional IFD 100 at least for the following reasons. First, main filter 203 is fully effective more quickly because charged particles begin passing through it almost immediately after turning on improved IFD 200. Second, the vast majority of suspended particles charged by ionizer 205 will likely pass through main filter 203, regardless of air flows outside of improved IFD 200. Third, charged particles are less likely to adhere to surfaces outside of improved IFD 200. Fourth, there is less decay of charge on the charged particles before they are filtered by main filter 203.

(14) The effectiveness of this design can be improved by further lengthening the time that the air and emitted charge are together inside the unit between the inlet and the outlet, thereby maximizing the charge mixing and therefore maximizing the filter efficiency. This may be accomplished by further lengthening the path in order to lengthen the time available for charge transfer, and in particular the airflow path between ionizer 205 and filter 203. For instance, as shown in FIG. 3, a serpentine path 208 can increase the length of airflow 210 without unduly increasing the exterior size of improved IFD 200. Such a serpentine path 208 is preferably disposed downstream from the ionizer 205, such as between fan 204 and main filter 203, or between ionizer 205 and fan 204. As shown in FIG. 2, baffles 207 or the like can also be introduced into airflow 210, such as downstream from ionizer 205 and upstream from main filter 203, in order to increase the path length, provide more turbulence for more effective mixing, and/or slow airflow 210 to provide more time for mixing.

(15) While there have been shown, described, and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions, substitutions, and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. For example, it is expressly intended that all combinations of those elements and/or steps which perform substantially the same function, in substantially the same way, to achieve the same results are within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

(16) Those skilled in the art will recognize that the present invention has many applications, may be implemented in various manners and, as such is not to be limited by the foregoing embodiments and examples. Any number of the features of the different embodiments described herein may be combined into one single embodiment, the locations of particular elements can be altered and alternate embodiments having fewer than or more than all of the features herein described are possible. Functionality may also be, in whole or in part, distributed among multiple components, in manners now known or to become known.

(17) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention. While there have been shown and described fundamental features of the invention as applied to being exemplary embodiments thereof, it will be understood that omissions and substitutions and changes in the form and details of the disclosed invention may be made by those skilled in the art without departing from the spirit of the invention. Moreover, the scope of the present invention covers conventionally known, future developed variations and modifications to the components described herein as would be understood by those skilled in the art.