阅读说明：本技术 无稀松布过滤介质和/或芳族聚酰胺过滤介质 (Scrimless filter media and/or aramid filter media ) 是由 F·C·怀瑟 B·凯普纳 于 2019-08-05 设计创作，主要内容包括：一种有源场极化过滤器,包括无稀松布过滤介质,所述无稀松布过滤介质包括聚丙烯纤维与聚甲基亚苯基间苯二甲酰胺纤维的混合物。所述混合物可以是具有重量比在5:95-50:50范围,甚至更优选在10:90-30:70范围的聚甲基亚苯基间苯二甲酰胺纤维与聚丙烯纤维的非织造材料形式。(An active field polarizing filter comprising a scrimless filter media comprising a mixture of polypropylene fibers and polymethylphenylene isophthalamide fibers. The mixture may be in the form of a nonwoven material having a weight ratio of polymethylphenylene isophthalamide fibers to polypropylene fibers in the range of 5:95 to 50:50, and even more preferably in the range of 10:90 to 30: 70.)

1. An active field/polarized media air cleaner comprising:

a first conductive outer mesh;

a second conductive web substantially parallel to the first conductive outer web;

a scrimless filter media disposed between the first and second conductive outer webs; and

a high voltage power supply having a first terminal and a second terminal, the first terminal of the high voltage power supply connected to the first conductive outer mesh and the second terminal of the high voltage power supply coupled to the second conductive mesh.

2. The active field/polarized media air cleaner of claim 1, wherein the scrimless filter media comprises a triboelectric material.

3. The active field/polarized media air cleaner of claim 2, wherein the triboelectric material is an aramid.

4. The active field/polarized media air cleaner of claim 2, wherein the scrimless filter media comprises polypropylene fibers and polymethylphenylene isophthalamide fibers.

5. The active field/polarized media air cleaner of claim 4, wherein the scrimless filter media comprises a layer of material having a weight ratio of polymethylphenylene isophthalamide fibers to polypropylene fibers in the range of 5:95 to 50: 50.

6. The active field/polarized media air cleaner of claim 4, wherein the scrimless filter media comprises a layer of material having a weight ratio of polymethylphenylene isophthalamide fibers to polypropylene fibers in the range of 10:90 to 30: 70.

7. The active field/polarized media air cleaner of claim 1, wherein the scrimless filter media comprises two support layers with one or more scrimless media layers therebetween.

8. The active field/polarized media air cleaner of claim 7, wherein one of the support layers is a top layer and the other of the support layers is a bottom layer, wherein the top layer faces in a direction of airflow.

9. The active field/polarized media air cleaner of claim 8, wherein the scrimless dielectric layer comprises modified acrylic fibers.

10. The active field/polarized media air cleaner of claim 8, wherein the scrimless dielectric layer comprises polypropylene blend fibers.

11. The active field/polarized media air cleaner of claim 8, wherein the top support layer is a nonwoven material.

12. The active field/polarized media air cleaner of claim 11, wherein the nonwoven material is selected from the group consisting of polyester, glass, and wool.

13. The active field/polarized media air cleaner of claim 8, wherein the bottom support layer is selected from the group consisting of a nonwoven material, a plastic mesh, a vinyl, and a non-conductive mesh.

14. The active field/polarized media air cleaner of claim 1, wherein the scrimless filter media is illuminated by UV light.

15. The active field/polarized media air purifier of claim 1, wherein the scrimless filter media comprises a plurality of layers, wherein at least one of the layers is treated with a photocatalyst.

16. The active field/polarized media air cleaner of claim 1, further comprising a second conductive outer mesh upstream of the second conductive mesh and an additional triboelectric filter layer having a material of a two-sided triboelectric level between the second conductive outer mesh and the second conductive mesh.

17. The active field/polarized media air cleaner of claim 16, wherein the first conductive outer mesh, the second conductive outer mesh, and the scrimless filter media are all contained within a module.

18. The active field/polarized media air cleaner of claim 17, wherein the module has a hinge proximate the scrimless filter media.

19. The active field/polarized media air cleaner of claim 17, wherein the module is a stand-alone cartridge.

20. An active field/polarized media air cleaner comprising:

a first conductive outer mesh;

a second conductive web substantially parallel to the first conductive outer web;

an aramid triboelectric filter media disposed between the first and second conductive outer meshes; and

a high voltage power supply having a first terminal and a second terminal, the first terminal of the high voltage power supply connected to the second conductive mesh, the second terminal of the high voltage power supply coupled to the first conductive outer mesh.

Background

Air filters typically use one or more layers of filter media in the airflow path to capture particles. Air passes through the media and airborne particles are collected by the media fibers. Filter media can be made of many materials, and certain filter materials, such as some nonwoven materials, are adsorbed to a scrim (scrim) or substrate layer because they cannot hold their shape without support. The scrim layer may be a loosely woven open layer or a nonwoven material in a pattern. The nonwoven scrim may include a densely packed structure and the yarns placed at angles to leave openings between the threads. The yarn density (yarns per inch in one direction) in the nonwoven scrim may be in the range of one to twenty yarns per inch, however, the volume of the nonwoven scrim falls within the range of one to ten yarns per inch. In theory, a nonwoven scrim can achieve a packing density of yarns because there is no interweaving to interfere with yarn placement. While many scrims are produced with yarns at right angles (as in a woven structure), the non-woven process can place the yarns at various angles and can lay multiple layers of yarns with various orientations.

Although there are exceptions, the basic difference between woven and nonwoven scrims is that weaving requires under and over interlacing, whereas in nonwoven scrims the yarns are stacked on top of each other and chemically held together. One of the most significant differences is the "straightness" of the yarns in the nonwoven scrim. In nonwovens, yarn properties are more directly converted to fabric properties, since there is mainly no "uncrimped" elongation and yarn/yarn friction associated with the weave geometry. Furthermore, in a nonwoven scrim, the yarns can be locked into place and do not collapse as in conventional woven lattices.

Most nonwoven scrims use multifilament yarns of polyester, nylon, glass, rayon, or polypropylene. Multifilament yarns are available, cost effective, relatively easy to process, tend to spread out and provide the desired "flat" profile, and provide good conversion of polymer properties to yarn form. Monofilaments are used, but their relative stiffness can create processing problems, such as low adhesive adhesion.

For woven or nonwoven scrims, the filtration layer may be attached to the scrim by needling the fibers to the scrim or using chemical, heat, resin, or stitch bonding.

Scrim material filter media have been widely used for many years and provide many benefits. However, the scrim itself will contribute to pressure drop and energy consumption with little or no increase in removal efficiency. And it has other drawbacks, as will be seen below.

In other filter areas, the principle of electrostatic attraction has been used for many years to enhance the removal of contaminants from air streams. There are three main categories of electrostatic air purifiers: electrostatic precipitators (electrostatic precipitators), passive electrostatic filters (passive electrostatic filters) and active-field/polarized-media air purifiers (active-field/polarized-media air cleaners), which are sometimes known in different terms.

The electrostatic precipitator charges the particles and then traps them on an oppositely charged and/or grounded collection plate.

Passive electrostatic filters (also known as electrets) employ a medium (or a combination of different media) that has an electrostatic charge through some combination of processing and/or inherent properties. The particles enter the filter media having an electrostatic charge and/or relative charge position, and the particles are attracted to the charged media filter material having an opposite electrostatic charge.

Active field/polarized media air purifiers use an electrostatic field generated by a voltage difference between two electrodes. A substantially dielectric filter medium is disposed in an electrostatic field between two electrodes. The electrostatic field polarizes the incoming media fibers and particles, thereby increasing the capture efficiency and load capacity of the media and air cleaner. Dielectric materials are electrical insulators or highly current-resistant substances that are also capable of storing electrical energy. Dielectric materials tend to concentrate the applied electric field within them and thus become effective supports for the electrostatic field.

Another electrostatic air filter design is disclosed in canadian patent 1,272,453, in which a disposable rectangular box is connected to a high voltage power supply. The cartridge (cartridge) consists of a conductive inner center screen sandwiched between two layers of dielectric fibrous material (plastic or glass). The two dielectric layers are in turn further sandwiched between two outer meshes of conductive material. The conductive inner core network is raised to a high voltage to create an electrostatic field between the inner core network and two conductive outer networks held at opposite or ground potential. The high voltage electrostatic field polarizes the fibers of the two dielectric layers.

The air purifier may be installed in a variety of configurations and situations, either as part of a Heating Ventilation and Air Conditioning (HVAC) system or as a stand-alone air moving/cleaning system. In smaller HVAC systems (e.g., residential and light commercial systems), the air purifier panels are typically mounted in a planar structure (perpendicular to the airflow) or an angled filter track. In larger systems, the air purifier panel groups are typically arranged in a V-shaped configuration, wherein a plurality of separate panels are positioned to form an air purifier module assembly perpendicular to the airflow axis.

Us patent 7,708,813; 8,252,095, respectively; 8,795,601 and 9,764,331, which are incorporated herein by reference in their entirety, show:

1) a filter media comprising two layers of fibrous dielectric material (e.g. polyester) with a higher resistance gas permeable material (e.g. fiberglass mesh) sandwiched between lower resistance dielectric (polyester) layers;

2) a filter media comprising a layer of fibrous dielectric material forming a mixed fiber layer containing fibers from triboelectric series of materials (triboelectric grades) from different ends for use in an active field/polarized media air cleaner for use in an active-field/polarized-media air cleaner;

3) a filter media comprising a layer of relatively lower density dielectric material (e.g. fibrous polyester) followed by a layer of relatively higher density material (e.g. denser fibrous polyester); and 4) the use of triboelectric materials (triboelectric materials) as filter materials in electrostatic fields.

In all configurations of active field, polarized media air cleaners, the electrostatic field significantly enhances the particle capture and loading capabilities of the media. However, in certain standard tests (e.g. ASHRAE 52.2) and certain industrial settings, highly conductive dust is present. This will create a path for the voltage to travel between the electrodes and there will be no electrostatic field present. Thus, the performance of the media used in active field/polarized media air purifiers after loss of the electric field is then an important factor in the overall system rating and use.

Accordingly, there is a need for an improved filter material for an active field polarized air filter.

Disclosure of Invention

The invention is embodied in a number of individual improvements and combinations of filter media in an active field/polarized media air purifier. It has been found that scrimless media is able to maintain submicron particle efficiency better than media of the same or greater fiber weight with a scrim. The scrimless media layer(s) may be a triboelectric blend (triboelectric blend) with its own structural integrity, such as an aramid blend (aramid blend), or the scrim-free layer may be a component layer that provides the necessary support. In one embodiment of the invention, the individual features include the following: an active field/polarization media air cleaner comprising an aramid blend and/or other triboelectric material filter media (triboelectric material filter media), which may be scrimless and may include a mixture of polypropylene fibers (polypropylene fibers) and polymethylphenylene isophtalamide fibers (polymetaphenylene isophtalamide fibers).

This mixture may be as described in US 6,328,788, which is incorporated herein by reference as if fully set forth herein, and sold under the trade name tex el, and as described in that patent, preferably in the form of a nonwoven material, having a weight ratio of fibers (2) to fibers (1) in the range of 5:95 to 50:50, and even more preferably in the range of 10:90 to 30: 70.

In another embodiment of the invention: an active field/polarized media air cleaner, as described below, includes a scrimless triboelectric layer(s) that has no structural integrity of its own and is held in place by a layer of other media pad assembly (media pad assembly).

Drawings

Fig. 1 is a perspective view of a plurality of active field/polarized media air cleaner panels arranged in a V-shaped configuration.

FIG. 2 is an assembly schematic of the use of a dielectric media support frame (a dielectric media support frame).

Fig. 3 is a schematic diagram of the components of the high voltage probe and high voltage contact (high-voltage contact) and the mesh (screen).

Fig. 4 illustrates the use of a dielectric media support frame.

Fig. 5 shows a rigid conductive outer mesh and a conductive holding frame comprising a high-voltage probe and a high-voltage contact shield (high-voltage contact shield).

Fig. 6 is a cross-sectional view of a plurality of active field/polarized media air purification filters arranged in a V-bank configuration.

FIG. 7 is a detail of a cross-sectional view of a plurality of active field/polarized media air purification filters arranged in a V-bank configuration, illustrating insertion of an alternative filter media into a lower filter holder.

FIG. 8 is a detail of a cross-sectional view of a plurality of active field/polarized media air cleaner filters arranged in a V-shaped configuration illustrating insertion of replacement filter media into an upper filter holder.

Fig. 9 and 10 show different cross-sections of the frame in fig. 4, with detailed views of the layers of filter material.

Detailed Description

Filter hardware

Fig. 1 shows a plurality of active field/polarized media air cleaner panels (filters) 101 arranged in a V-bank configuration 100. The individual filter panels 101 may be referred to herein as "panels", "filters", and/or "air cleaners". The plurality of active field/polarized media air purifiers 101 are organized into a plurality of stackable modules 102, each module having a width W, a height H, and a depth D that vary depending on the application. In particular, the V-shape 100 in fig. 1 contains eight stackable modules 102, each containing eight separate active field/polarized media air purifiers, for a total of 64 air purifiers. Although shown in a V-shaped configuration 100, it should be understood that the air purifiers may be inserted into the airflow at a vertical or other angle, alone or in other combinations and/or arrangements.

An active field/polarized media air purifier is shown in fig. 2. A first mat (pad)16A of fibrous dielectric material is disposed over the center screen 110, which extends as shown, but need not so extend to the edges of the entire frame to maximize field coverage. On the other side of the central screen 110 is a second pad of dielectric filter material 16B. The first pad of dielectric filter material is sealed and/or attached to the dielectric media support frame 120 by suitable means, such as adhesive material 121A, ultrasonic welding, or compression. Although sealing of the media in the module and sealing of the module in the air stream is critical for maximum single-pass performance (single-pass performance), the filter material may not seal for assembly cost savings or for maintenance reasons, for example when the filter material is designed for applications that require less stringent performance, such as residential or light commercial buildings.

Above the first pad of dielectric filter material 16A is a first upstream conductive outer screen 12A. Below the second pad of dielectric filter material 16B is a second conductive downstream outer screen 12B (the use of "first" and "second" conductive outer screens in the claims may be reversed so as to introduce the compositions therein in order). The second pad of dielectric filter material is attached to the dielectric media support frame 120 by suitable means, such as adhesive material 121B, ultrasonic welding, or compression. The first conductive outer screen 12A is held in place by a first conductive holder 116A. The second conductive outer screen 12B is held in place by a second conductive holder 116B. Although the outer nets, which are shown as grounded in the figures, are referred to herein as conductive, it should be understood that in some applications they may comprise some resistive material.

The filter media itself includes a dielectric media support frame 120, a first pad of fibrous dielectric material 16A, a center screen 110, and a second pad of dielectric filter material 16B. The filter holder supporting the filter media includes a first conductive or insulating holder 116A having a first conductive outer mesh 12A, and a second conductive or insulating holder 116B having a second conductive outer mesh 12B.

In operation, one terminal of the high voltage power supply 108 is connected to the center screen 110. The other terminal of the high voltage power supply 108 is coupled to the first and second conductive outer nets 12A and 12B, which are normally held at ground potential (at ground potential).

Particles in the incoming air pass through the dielectric filter materials 16A and 16B of the active field/polarized media air cleaner of fig. 16, are polarized by the electric field therein, and are collected on the first and second pads of dielectric filter material 16A and 16B.

In fig. 3 is shown a high voltage contact protected by a high voltage shield to reliably contact the center screen 110. The contacts 136 pass through holes in the central web 13 (or may make such contact with the edges of the web if not desired or practical). The conductive element 133 protects the contact 136 to the central mesh 13, providing a good connection between the contact 136 and the live electrode or the central mesh 13. The contacts may be rivets, stud-eyed rivets, screws, bolts, washers, balls, or the like. The common thread between the selected contacts is to widen the contact area with the center screen and to provide a wider contact point for the high voltage electrode. The ideal material for these components is corrosion resistant and may be metallic or conductive plastic or other material.

A high voltage probe 130 passes through the conductive outer mesh 12A and terminates in a high voltage contact 134. In some embodiments, grommet, bezel(s), grommet(s) may be used to provide an electrically uniform ground surface (electrical even ground) rather than non-uniform points (uneven points) that may result from cutting a perforated sheet or web. A high voltage shield of insulating dielectric material 132A surrounds the high voltage contact 134. Similarly, a high voltage shield of insulating dielectric material 132B surrounds the lower end of the rivet 136 and the metal disc 133. Alternatively, the high voltage probe may be routed inside the conductive outer nets 12A, 12B.

The high voltage probe 130 may be of various materials and types. For example, it may be rigid wire or flexible. It must be able to conduct high voltages, but it can be metallic or composite. It may be a unitary piece or have end-caps or fittings.

Fig. 4 shows a top view of the filter medium of fig. 3. A dielectric media support frame 120 surrounds the dielectric filter material pad 16A. A rivet or connecting device 136 is passed through the pad of dielectric filter material 16A.

FIG. 5 shows a top view of a frame supporting filter media. The four conductive outer filter holder pieces 116 and the four end corners 128 form a frame to support the conductive outer screen 12. The high voltage contact 134 is positioned within the insulating high voltage shield 132A.

In operation, the high voltage contact 134 contacts the head of the rivet 136 when the conductive outer filter retainers 116A and 116B (fig. 3) are closed around the filter media (120, 16A, 13, and 16B). Also, the high voltage shields 132A and 132B slightly compress the pads of dielectric filter material 16A and 16B. The high voltage contact 134 ensures a reliable connection with the head of the rivet 136. The dielectric high voltage shields 132A, 132B reduce the likelihood of tip ejection (spraying) and corona (corona) from the high voltage contacts 134. In addition, the insulating high voltage shields 132A, 132B reduce the chance of arcing from the high voltage contacts 134 to the conductive outer nets 12A and 12B.

In one embodiment of the present invention, the high voltage contactor 134 is generally made of a rigid wire or other resilient material. The center screen 13 may be slightly bent when in contact with the head of the rivet 136. Alternatively, the high voltage contacts 134 may be spring contacts to reduce bending of the center screen 13. An alternative arrangement for the contact area 136 on the center screen 13 includes a conductive disk on the top side of the center screen 13, a pair of conductive elements, one on top of the center screen and the other on the bottom of the center screen, with fasteners passing through the center screen and holding the two disks together. The rigidity of the high voltage probe 134 or the rigidity of the outer conductive outer mesh or a combination of both forces positive mechanical contact (positive mechanical contact) between the end of the high voltage probe 134 and the disc or disc/rivet combination 136. The result is a firm contact that is not compromised by vibration, or media movement or central mesh (electrode) movement.

In another embodiment of the invention, the high voltage probe may be permanently or removably attached (e.g., with a two-piece snap or firing nut/connector) to the center, edge, or otherwise of the center screen such that it conducts electrical current.

In another embodiment of the present invention, the magnets 202, 204 may be moved to facilitate safe and aligned high voltage contacts. Alternatively, portions of the high voltage probe 130 and the contact 136 may be made of magnetic material.

Fig. 6 shows a cross-sectional view of a single module 102 of fig. 1. Each individual active field, polarized media air purifier 110A, 110B, 110D, 110E, 110F, 110G, and 110H is held in place in a V-shaped arrangement. At the front of the module 102, a plurality of cowlings (cowlings) hold each filter in place. In particular, there are two end fairings 104A and 104B at the top and bottom of the module 102. Between the two end fairings, there are three intermediate fairings 106A, 106B and 106C. The aerodynamic shape of the cowling provides a lower form of airflow resistance, thereby reducing the static (air resistance) of the filter.

At the rear of the module 102 (fig. 6), multiple double hinges may hold each filter in place, or the upper and lower frames 114a, 114b may be held in place in the receiving channel 119, or the entire filter air purifier 110a, etc. may be contained in a separate box (self-contained cartridge) that cannot be accessed without further effort, such as screw removal or breakage.

In the hinged embodiment, each double hinge comprises three hinges H1, H2, and H3, as better seen in the operation of fig. 7 and 8. As shown in fig. 7, the first hinge H1 has a first connection point coupled to the upper frame 112A and a second connection point coupled to the lower frame 112B. The hinge Hl has a pivot point (a pivot point) that allows the lower frame 112B to rotate away from the upper frame 112A to allow insertion of replacement filter media into the active field/polarized media air purifier 110G. Similarly, as shown in fig. 8, the second hinge H2 has a first connection point coupled to the upper frame 114A and a second connection point coupled to the lower frame 114B. The hinge H2 has a pivot point that allows the upper frame 114A to rotate away from the lower frame 114B to allow insertion of replacement filter media into the active field/polarized media air purifier 110H.

A third hinge H3 serves as a first connection point coupled to the first hinge H1 and a second connection point coupled to the second hinge H2. The third hinge H3 has a third pivot point such that the upper active field/polarized media air cleaner frame (112A, 112B) can rotate as a unit relative to the lower active field/polarized media air cleaner frame (114A, 114B). The use of dual hinges at the rear of the module 102 provides flexibility in mounting the source field/polarized media air purifiers at different angles relative to each other. The double hinge at the rear of the module 102 also provides a good air seal at the rear of the filter regardless of the different angles at which the individual air purifiers are installed. The positive seal provided by the double hinge at the rear of the filter reduces air leakage, i.e., a portion of the air flow passes through the filter assembly and not through the filter media.

Although the foregoing invention has been described with reference to various embodiments, modifications may be made in the construction and elements of the invention without departing from the spirit and scope of the invention. For example, panels may be used individually or in a fixed and/or partially or fully movable array to slide into the track. Panels made of a variety of materials employ a variety of voltages, spacings, and electrostatic field strengths.

Filter medium

Fig. 9 and 10 show different cross-sections of the frame in fig. 4, as well as detailed views of the layers of filter material.

As shown in fig. 9, the frame member 116 holds three or more layers therein, the upstream layer 16A may or may not include a triboelectric fiber mixture, and a center screen 13, as has been described and referenced herein. The frame member 116 may also include a scrimless aramid layer 96 comprising a blend of polypropylene fibers and polymethylphenylene isophthalamide or other aramid fibers. The mixture may be as described in U.S. Pat. No. 6,328,788, the contents of which are incorporated by reference as if fully set forth herein, and sold under the trade designation TEXEL, and as described therein, preferably in the form of a nonwoven material, having a weight ratio of polyisophthaloyl metaphenylene diamine fibers to polypropylene fibers in the range of 5:95 and 50:50, and even more preferably in the range of 10:90 and 30: 70. Aramid is generally prepared by the reaction between an amine group and an acid halide group. The most well known aramids (Kevlar, Twaron, Nomex, New Star and teijin conex) are AABB polymers. Other aramids contain predominantly meta-linkages and are poly-m-phenylene isophthalamide (MPIA). Kevlar and Twaron are both p-phenylene terephthalamide (PPTA), the simplest form of AABB p-polyaramid (para-polyaramide). PPTA is the product of p-phenylenediamine (PPD) and terephthaloyl dichloride (TDC or TCl).

In use, the product of US 6,328,788 may not require a scrim layer due to the strength of the aramid. This also reduces the pressure drop.

By placing aramid layer 96 downstream of layer 16A, the filter can capture the larger particles in the coarser filter first, and then the finer particles, while minimizing pressure drop. However, these layers may be exchanged, or the ordinary layer or layers of 16A may be absent and replaced with other possible aramid layers. It should be understood herein that the aramid layer 96 is a triboelectric material, but is represented separately from the more general layer 16A, which may or may not contain a triboelectric blend.

Fig. 10 shows another embodiment of a cross-section, which may include a layer similar to fig. 9 and a central screen 13. In addition to these, there is a scrimless filter layer assembly 1000 that includes a top support layer 1010, a scrimless media layer 1020, and a bottom support layer 1030. The support layers provide structural support in the sense that they impart shape to the filter media (as can the webs), and they also prevent the aramid layer from blowing apart or otherwise losing its shape when subjected to air flow and/or contact.

The scrim-free media layer 1020 may comprise a nonwoven fiber blend that would otherwise be brittle and structurally weak enough to hold its shape when the filter assembly (scrim-free) is in use, but otherwise has excellent filtration quality. Examples of such materials include modified acrylic (mod-acrylic) and polypropylene blends and/or other triboelectric or non-triboelectric blends. The scrim-free material layer may also be a single type of material. The function of the support layer is to maintain the non-scrim layer intact during manufacture, handling and use.

The scrimless media layer 1020 may be one or more layers as shown, or include other combinations that help the scrimless media layer 1020 retain its shape and are more durable due to the support of the top support layer 1010 and the bottom support layer 1030. The top support layer may be of various materials, but desirably is a durable and relatively low pressure drop fabric, non-woven or perforated material such as polyester, polypropylene, nylon, other plastic or composite materials, glass, wool, extruded netting (extruded netting), or the like.

The bottom support layer 1030 (and possibly not necessarily at the "bottom") that may experience more contact during installation of the support frame 1020 may be a woven, non-woven or perforated material, plastic mesh, vinyl screen, metal mesh or even a mesh material or other support material. It may also be used as an outer conductive mesh in the assembly. The above descriptions are those currently described, but other support layers are possible.

The layers or conductive ground screens in the cross-sections shown in fig. 9 and 10 may not necessarily be uniform, or may be a single layer, and may include:

-a vinyl group;

-a polyester;

-glass

-wool;

-aramid (aramid) and material from the other side of the triboelectric grade (from the other side of the triboelectric scale);

-the above additionally comprises polypropylene;

-the above as described in U.S. Pat. No. 6,328,788 and/or sold as TEXEL;

-the above with or without a scrim;

-any of the above as part of a layered medium, wherein the other layers may be any of the above;

-triboelectric or non-triboelectric any other filter material;

-any of the above plus an arc-shaped barrier layer (arc block layer);

-any of the above with PCO;

and combinations thereof.

In another embodiment of the present invention, one of the dielectric layers may be treated with a photocatalytic material. The air purifier may then be combined with UV light to decompose the gas phase contaminants. The hydroxyl radicals produced in this embodiment can inactivate biological substances and destroy gas phase contaminants. In this embodiment, under the influence of UV light, the medium produces hydroxyl radicals and superoxide ions to react with the captured and airborne bioaerosols and gas phase contaminants. The photocatalytic layer may be the most downstream layer. This will keep the photocatalytic layer substantially free of particle contamination.

In another embodiment of the invention, the outer mesh/electrode of the filter frame is treated with a photocatalyst.

In another embodiment of the invention, some or all of the conductive mesh (central or grounded) has odor/gas phase contaminant adsorption properties, such as a carbon impregnated foam or mesh.

In another embodiment of the invention, one or more of the layers may be a material treated with a catalyst for decomposing VOC's, other reactive gas phase contaminants and/or ozone and/or biological contaminants.

In another embodiment of the invention, one or more of the layers contains adsorbable or chemisorbed fibers and/or fibers with an adsorbable or chemisorbed coating.

In another embodiment of the invention, one or more of the layers contains biocidal fibers and/or fibers with a biocidal coating.

Test results

Table 1 shows various third party tests comparing results of ASHRAE standard 52.2 tests. The 52.2 test measures twelve upstream and downstream efficiencies ranging in size from 0.3 to 10.0 microns. During the testing process, various efficiencies were achieved when the device was loaded with test dust that included a high percentage of carbon black and was highly conductive, unlike typical atmospheric dust. The lowest efficiencies achieved are divided into three groups: e1(0.3 to 1.0 micron), E2(1.0 to 3.0 microns), and E3(3.0 to 10.0 microns). The individual results for each size within the group were averaged together. The efficiency rating is based on the average number reached in each category and the result of a Minimum Efficiency Reporting Value (MERV) rating for the device. For high efficiency air filters and purifiers, E1 efficiency is critical. In the case of an active field/polarized media air purifier, the conductive dust causes a voltage to travel from the center screen to the ground screen, shorting the system and de-energizing the electrostatic field, thereby affecting the effect of the electrostatic field on the particles and media fibers. It is important to note that the filter rating is based on a 10% or less change in efficiency of E1. Thus, small improvements in submicron particle removal are important and have a large impact on the suitability and use of the product in certain markets. For example, most filtration in hospitals must meet a minimum MERV 14, E1 between 75% and 85%.

Table 1 shows various air purifier components, all of which have substantially the same structure, with one or more layers of triboelectric dielectrics added. They were ranked according to the E1 results in the standard 52.2 test. Assemblies employing scrimless media perform much better than similar media with scrims or media of greater triboelectric dielectric weight. This is especially true in the critical submicron range. For example, the most significant comparison is between tests 1 and 8. Here, 350g of the triboelectric dielectric with scrim contrasts with 330g of the triboelectric dielectric without scrim. Scrimless media are nearly 20% better in both E1 efficiency and minimum 0.3 micron performance. Each comparison of scrim media to scrimless media shows essentially the same relationship. In all cases, this difference was most pronounced in the submicron/E1 range, where E2 and E3 were essentially identical. In addition, scrimless media for aramid blends are generally preferred over scrimless modified acrylic/polypropylene blends based on basis weight and pressure drop.

TABLE 1

Note:

1) BHT is Blue Heaven technologies (Blue Heaven technologies) in Louisville, Ky.

2) The NS prefix indicates that there is no scrim on the media.

3) The WS prefix indicates that there is a scrim on the media.

4) The MAP suffix indicates a modified acrylic/polypropylene blend.

5) The AB suffix indicates and aromatic polyamide blend.

The above disclosed invention can be used in a variety of ways, including but not limited to use in HVAC systems, stand-alone filter/fan units, industrial air purification systems, and dust collectors. Although the above embodiments primarily describe a planar filter structure, the invention is also applicable to other structures including, but not limited to, V-bank combinations of multiple planar panels, interconnected combinations of panels and V-bank units, bag filters, pleated and mini-pleated filters, cartridge filters, and cylindrical filters for dust collection systems.

Although the foregoing invention has been described with reference to various embodiments, modifications may be made in the structure and elements of the invention without departing from the spirit and scope of the invention. In particular, various layers or elements may be combined, interchanged, and/or repeated to achieve various effects. For example, while one figure illustrates the basic concept of an air purifier, another figure illustrates the construction of one type of assembly system. Although the various elements have been shown as separate layers for clarity, two or more "layers" may be combined into a single layer or material.