Abstract: An electrostatic filter having an improved dielectric is described. The dielectric constitutes a dielectric mat formed from high porosity non-woven fibers having pores that have a void fraction of at least 97%. The dielectric mat is sandwiched by a pair of porous electrodes. The fibers that form the mat have a maximum cross sectional thickness that is less than 100 microns and a length to maximum thickness ratio of greater than 10. The pores are preferably statistically substantially equally sized and open in three dimensions. In various preferred embodiments, the void fraction of the dielectric mat is greater than 99 percent. The mat preferably has a tortuosity of at least 2. The maximal cross sectional width of the fibers is preferably in the range 0.1 to 50 microns. In many implementations, the fibers that form the dielectric mat are formed from either polyester or polypropylene.

Abstract: Disclosed is an air purifier having a small size so as to be easily mounted to various home appliances, and preventing ozone which is harmful to a human body from being generated, the air purifier including an insulating dielectric including a solid; a discharge electrode provided in the insulating dielectric; a ground electrode provided in the insulating dielectric and spaced for a predetermined distance from the discharge electrode; and a power supply coupled with the discharge electrode and the ground electrode for supplying a high voltage thereto.

Abstract: An electro-mechanical electrostatic air cleaner that combines a low air resistance dielectric fibrous filter material positioned between and electrically charged by two electrically resistant carbon coated screens. The screens are charged by a remotely mounted bi-polar power supply. A pair of post ionization electrodes charge particles in the air with opposite charges, causing the particles to agglomerate. A plurality of screens may be placed in an array for increased one-pass filtration.

Abstract: Disclosed is an air purifier with a small size, having an excellent air purifying capacity, capable of preventing a large amount of ozone from being generated, the ozone harmful to a human body. The air purifier includes a case, a pair of discharge electrodes provided at upper and lower parts of the case, a ground electrode provided between the pair of discharge electrodes, a pair of insulating dielectric layers provided on upper and lower surfaces of the ground electrode, and a power source coupled respectively to the ground electrode and the discharge electrode so as to supply voltage thereto.

Abstract: An electret article that includes a polymeric material that has electric charge imparted thereto, that has one or more heteroatoms, that has a fluorosaturation ratio of less than 200, and that has an atomic percent fluorine of greater than about 40%. The inventive electret article is resistant to charge degradation upon exposure to high temperatures for prolonged time periods.

Abstract: An electret article that includes a polymeric material that has electric charge imparted thereto, that has a CF3:CF2 ratio of at least 0.15 and that has a fluorosaturation ratio greater than about 200. The electret article may be in the form of a porous web of polymeric fibers suitable for use as a filter. The inventive electret article is resistant to charge degradation upon exposure to high temperatures for prolonged time periods.

Abstract: In a plasma air dust collector, the plasma air dust collector includes a first electrode fixing unit and a second electrode fixing unit respectively having a power terminal; at least two dust collecting electrodes; a discharge electrode arranged between the dust collecting electrodes; a terminal protrusion formed at the bottom end of each dust collecting electrode in the length direction; a terminal protrusion insertion hole formed at a side of the first electrode fixing unit; a combining protrusion formed at a side of the first electrode fixing unit and the second electrode fixing unit; and a combining groove formed at the both ends of each dust collecting electrode.

Abstract: Ionic emission electrostatic device (1) for depositing on the surface (sp) of a multitude of aerosol particles (p1, p2, . . . , pn) within a fluid (F), a quasi-homogeneous quantity of ions (iq). This electrostatic device (1) is constituted by a conductive discharge corona electrode (EC) and a noncorona conductive receptor electrode (ER). The pseudo-planar active face (SA) of its receptor electrode (ER) is covered by a plurality of craters with sharp edges, in a closed pseudo circle, exhibiting on their end edges (Ai) a section of minimum bend radius, and enclosing the orifices (O1, O2, . . . , On) and terminating towards the outside of the active face (SA). The craters are distributed quasi-uniformly on the active face (SA), in its two geometric directions. The surface flow of ions (iq) originating from the corona electrode (EC) and in the direction of the active face of the receptor electrode (ER) has an increased homogeneity.

Abstract: A respiratory filter includes an air-permeable sleeve and at least one filter layer that is arranged in the sleeve and contains activated carbon. The activated carbon contained in the filter layers serves as a gas filter that, by absorption, at least partially removes the noxious gases that are contained in the air inhaled.

Abstract: The invention refers to a composite filter for filtering a stream of ambient air including at least one non-prebonded upstream tier and one non-prebonded downstream tier, wherein the ratio of absolute pore volume of upstream tier to downstream tier RAPV>2, and the absolute projected fiber coverage of upstream tier and of downstream tier APFC>95%. Further, the invention refers to a method of making such a composite filter including the steps of (a) laying down a filtration material onto a support to form the upstream non-prebonded tier, (b) depositing onto the upstream tier the downstream non-prebonded tier, and (c) bonding the tiers to form a composite filter having a unitary stratified structure.

Abstract: Particle separator having a flow passage for air to be cleaned from electrically charged particles includes at least two electrode element surfaces arranged substantially parallel to each other and at a mutual gap width (d), at least one electrode element surface being designed from a very high ohmic material, preferably with a resistivity corresponding to or higher than antistatic. The particle separator also is intended to be connected to a high voltage source, the second electrode element surface being intended to be connected to the pole of the high voltage source having the lowest absolute potential.

Abstract: Electrostatic precipitator (ESP) systems and methods are provided. A system includes at least one corona discharge electrode and at least one collector (and likely, at least a pair of collector electrodes) that extend downstream from the corona discharge electrode. An insulated driver electrode is located adjacent the collector electrode, and where there is at least a pair of collector electrodes, between each pair of collector electrodes. A high voltage source provides a voltage potential to the at least one of the corona discharge electrode and the collector electrode(s), to thereby provide a potential different therebetween. The insulated driver electrode(s) may or may not be at a same voltage potential as the corona discharge electrode, but should be at a different voltage potential than the collector electrode(s).

Abstract: A dust collecting apparatus for an air conditioner, including an ionizer to electrically charge dust particles in air; and a metal filter having fine metal fibers, disposed at a predetermined distance from a back of the ionizer, the metal filter having a polarity opposite to that of the charged dust particles to electrically collect the dust particles.

Abstract: A filter assembly particularly useful in electronically enhanced air cleaning systems including a fibrous filter media. A conductive electrode is affixed to the fibrous filter media, so that the conductive electrode makes physical contact to the fibrous filter media in a plurality of substantially planar locations. The conductive electrode is coupled to a potential that enables neutralizing charge that accumulates on the filter media during operation to be removed thereby maintaining high efficiency.

Abstract: A particle precipitation device for removing particles entrained in a gas stream includes an array of passages through which a gas stream can be directed relatively freely. The passages are provided between plastics walls adapted to create an electrical field within the array. The plastics walls may have areas of conductive material in contact therewith. High and low electrical potentials alternately applied to isolated areas of the conductive material provide charged sites in the array for collecting particles from the gas stream. Alternatively, the plastics walls may have electret properties.

Abstract: A portable air filtration system includes a filter housing having an air inlet and outlet. The housing defines a filtration chamber between the inlet and outlet. The air filtration system uses an intake fan, an ionizing mechanism, a filter media, and a conductive coating to filter air. The fan moves the air through the chamber. The ionizing mechanism ionizes particles within the air to a negative charge. The media includes an upstream side facing the inlet and a downstream side facing the outlet and is disposed between the ionizing mechanism and the outlet to entrap the particles. The conductive coating is applied to the upstream side of the media. This establishes an electric field between the ionizing mechanism and the conductive coating. Furthermore, the upstream side of the media is electrically-connected to ground through the conductive coating for dissipating the negative charge of the particles entrapped within the media.

Abstract: An improved cartridge, typically in cylindrical or panel form that can be used in a dry or wet/dry vacuum cleaner. The cartridge is cleanable using a stream of service water, or by rapping on a solid object, or by using a compressed gas stream, but can provide exceptional filtering properties even for submicron particulate in the household or industrial environment. The cartridge has a combination of nanofiber filtration layer on a substrate. The nanofiber and substrate are engineered to obtain a maximum efficiency at reasonable pressure drop and permeability. The improved cartridge constitutes at least a substrate material and at least a layer including a non-woven, fine fiber separation layer.

Abstract: A method for the utilization of a woven or loop-formingly knitted fabric which acquires an electrostatic charge as a result of a specific treatment for filtering airborne, dusty allergens such as pollen in a pollen guard mountable in front of windows and doors over the whole area thereof.

Abstract: A portable air filtration system includes a filter housing having an air inlet and an air outlet. The filter housing defines a filtration chamber between the air inlet and the air outlet. The portable air filtration system uses an ionizing mechanism, a filter media, and an electrode to filter air. The ionizing mechanism ionizes particles within the air to a negative charge. The filter media is disposed between the ionizing mechanism and the air outlet for entrapping the particles. The electrode is disposed between the ionizing mechanism and the filter media to establish an electric field. The electric field is established between the ionizing mechanism and the electrode adjacent to the filter media. The electrode is also electrically-connected to ground and to the filter media for dissipating the negative charge of the particles entrapped within the filter media.

Abstract: The invention describes a multi-layer filter structure and the use of a multi-layer filter structure for the dust removal from gases, wherein a coarse dust filter layer, a fine dust filter layer, and a support layer are disposed behind one another in the direction from the inflow side to the outflow side, and which is designed such that the fiber diameter distribution within the coarse dust filter layer and fine dust filter layer has a gradient, and that the fiber diameters of the coarse dust filter layer and fine dust filter layer continually decrease from the inflow side to the outflow side. This multi-layer filter structure may be used in a filter cassette for industrial dust removal, as well as in a stationary or mobile home dust cleaning device.

Abstract: A collecting device for collecting particles floating in the atmosphere includes a collecting container; a pump for sucking the atmosphere into the collecting container; a discharge electrode disposed in the collecting container for generating single polarity ions to charge the particles in the collecting container; and a dust-collecting electrode for collecting the charged particles in the collecting container through a potential difference between the discharge electrode and the dust-collecting electrode. The dust on the dust-collecting electrode is measured and analyzed.

Abstract: A collecting device for collecting suspended particles includes a mobility analysis device; a collecting container connected to an outlet of the mobility analysis device; a discharge electrode disposed inside the collecting container for charging the particles inside the collecting container by generating single polar ions; and a collecting electrode for collecting the charged particles inside the collecting container by an electric potential difference relative to the discharge electrode. In the mobility analysis device, the particles are charged and guided into a flow path. An electric field is created in the flow path, and the particles are guided into the path perpendicular to the electric field. Since a mobility of a particle in an electric field depends on a size of the particle, the particles guided in the path are separated according to the electric field, thereby obtaining particles with sizes in a specific range.

Abstract: A particle filter for microelectromechanical systems is provided that includes a particle trap formed on a substrate material. The particle trap includes an array of multidimensional geometric structures in an adjacent relationship. The geometric structures further define a plurality of multidimensional voids therebetween for trapping particles therein. The individual multidimensional geometric structures are formed by a plurality of vertically interconnected geometric shapes to define different configurations of voids between the adjacent geometric structures. In one embodiment of the filter system, an electrical bias is applied to the array of multidimensional geometric structures to facilitate attracting and trapping of particles in the filter.

Abstract: We claim an improved cartridge, typically in cylindrical or panel form that can be used in a dry or wet/dry vacuum cleaner. The cartridge is cleanable using a stream of service water, or by rapping on a solid object, or by using a compressed gas stream, but can provide exceptional filtering properties even for submicron particulate in the household or industrial environment. The cartridge has a combination of nanofiber filtration layer on a substrate. The nanofiber and substrate are engineered to obtain a maximum efficiency at reasonable pressure drop and permeability. The improved cartridge constitutes at least a substrate material and at least a layer comprising a non-woven, fine fiber separation layer. The nanofiber layer has a fiber diameter of about 0.05 to 0.5 micron, a nanofiber layer basis weight of about 3×10−7 to 6×10−5 gram-cm−2, an air permeability of about 1 to 1000 ft/min at 0.5 inch (water) &Dgr;P, and a pore size of about 0.01 to 100 microns.

Abstract: A particle precipitation device for removing particles entrained in a gas stream includes an array of passages through which a gas stream can be directed relatively freely. The passages are provided between plastics walls adapted to create an electrical field within the array. The plastics walls may have areas of conductive material in contact therewith. High and low electrical potentials alternately applied to isolated areas of the conductive material provide charged sites in the array for collecting particles from the gas stream. Alternatively, the plastics walls may have electret properties.

Abstract: There is disclosed an electrostatically charged filter material comprising a blend of polyester fibers and electrostatically chargeable fibers of at least one other kind.

Abstract: An electret is described that includes a surface modified polymeric article having surface fluorination produced by fluorinating the polymeric article.

Abstract: The invention concerns a volume generator (1) of chaotic electrostatic field (E), locally amplified, to subject a fluid (U) loaded with aerosol parties (P, p) to the action of an electrostatic field (E) highly variable in amplitude and orientation locally. This generator (1) includes: an induced electrostatic module (2), consisting of a porous dielectric material (md), two porous electrodes with electrostatic induction (4, 5), an electrical current source (6), and a device for boosting the fluid. The electrostatic module (2) consists of a three-dimensional grid system (Rxyz) having at least locally three-dimensional periodicity (or pseudo-periodicity) in at least three directions. Each grid of the system consists of an externally convex and internally concave elementary cell recessed in its center for including a compact elementary empty cellular volume (V1), that is with transverse dimensions (dx1, dy1, dz1) of the same order of magnitude in the three directions.

Abstract: A vapor phase treated electret filter media includes an additive or mixtures thereof that enhance the charge stability of the media. The filter media achieves acceptable alpha values for a range of filtration challenges without significant decay in alpha values over time. Preferred charge additives include fatty acid amides and mixtures thereof. Exemplary vapor phase deposition monomers include fluorinated monomers.

Abstract: An electret filter media includes an additive or mixtures thereof that enhance the charge stability of the media. The filter media achieves acceptable alpha values for a range of filtration challenges without significant decay in alpha values over time. Preferred charge additives include fatty acid amides, oleophobic fluorochemical surfactants, and mixtures thereof.

Abstract: A filter system with a housing defining a passage between an inlet and an outlet and one or more structures located in the passage in the housing. Each of the structures comprises two or more layers of insulating materials with an imbedded fixed charge located at at least one of the interfaces between the two or more layers. At least one of the structures has an imbedded fixed charge at a charge level of at least 1×1012 charges per cm2.

Abstract: A respiratory filter includes an air-permeable sleeve and at least one filter layer that is arranged in the sleeve and contains activated carbon. The activated carbon contained in the filter layers serves as a gas filter that, by absorption, at least partially removes the noxious gases that are contained in the air inhaled.

Abstract: A particle precipitation device for removing particles entrained in a gas stream includes an array of passages (10) through which a gas stream can be directed relatively freely. The passages are provided between plastics walls adapted to create an electrical field within the array. The plastics walls may have areas of conductive material (1, 2) in contact therewith. High and low electrical potentials alternately applied to isolated areas of the conductive material provide charged sites in the array for collecting particles from the gas stream. Alternatively, the plastics walls may have electret properties.

Abstract: An air filter includes a stack of filter discs formed with contacting faces having surface formations defining filtering passageways between adjacent discs for removing solid particles from the air passing through the stack. The filter discs in the stack further include electrodes spaced from each other axially of the stack and connectable to a voltage source for producing an electrical field attracting solid particles towards the discs to thereby enhance removal of the solid particles from the air passing through the stack. The filter discs in the stack include a first plurality of insulating discs composed of insulating material, and a second plurality of electrode discs composed of electrically-conductive material, with the electrode discs separated from each other by at least one insulating disc.

Abstract: A dust filter bag having a highly porous backing material ply and a method for producing the dust filter bag. The dust filter bag includes at least one filter material ply and at least one backing material ply, the backing material ply possessing an air permeability of at least 900 l/m2 x s, a burst strength of at least 70 kPa, a rupture strength longitudinally better than 10 and transversely better than 3 N, a flexural rigidity longitudinally better than 0.5 cN cm2 and transversely better than 0.25 cN cm2, a basis weight of 30-80 g/m2 and a droplet sink-in time of less than 10 minimum. The dust filter bag can be produced by the following steps: mixing fibers including cellulose fibers and fusible fibers into a homogenous fiber mix, processing the fiber mix into a fiber web by wet laying, drying the fiber web, curing the dried fiber web by thermofusion into a backing material ply, processing the backing material ply with a filter material ply into a raw bag, and finishing the raw bag into a dust filter bag.

Abstract: A multi-layer air filter is described, including a filter layer which is covered by a prefilter layer on the dust-laden gas side, which has a laid dry electrostatically effective nonwoven fabric, preferably a staple fiber nonwoven fabric, whose area weight is 10 through 100 g/m2. In particular, the filter may be used as a vacuum cleaner bag.

Abstract: A dust is electrostatically charged using an ion-releasing device adapted to release only ionized air with occurrence of a corona discharge, thereby reducing the amount of power consumed and the amount of ozone generated to the utmost. An electric dust collector includes a charging section having a discharging electrode and an earthed electrode, a dust-collecting section having a voltage-applied electrode and an earthed electrode and an air feed fan. Dust introduced into the dust collector is electrostatically charged by breaking the air insulation by a corona discharge occurring in the charging section to produce ionized air and then removed in the dust-collecting section where an electric field is formed. However, because the corona discharge is generated, there is a problem that the discharged current is large, and the amount of power consumed and the amount of ozone generated are large.

Abstract: The invention relates to a method and device for separating materials in the form of particles and/or drops from a gas flow, in which method the gas flow is directed through a collection chamber the outer walls of which are grounded, and in which high tension is directed to the ion yield tips arranged in the collection chamber, thus providing an ion flow from the ion yield tips towards the collection surfaces, separating the desired materials from the gas flow. It is characteristic of the invention that the collection surfaces conducting electricity are electrically insulated from the outer casings; and that high tension with the opposite sign of direct voltage as the high tension directed to the ion yield tips is directed to the collection surfaces. According to an embodiment of the invention the electrical insulation is made of ABS, and the surface conducting electricity comprises a thin chrome layer arranged on the insulation layer.

Abstract: An electrostaticly charged filtration media is provided including a plurality of polymeric structured polymeric film layers having a structured surface defined on at least one face of each structured film layer forming at least in part flow channels. The plurality of structured film layers are configured as a stack with the structured surfaces defining a plurality of ordered inlets open through a face of the stack that are in fluid communication with ordered fluid pathways. Each fluid pathway is defined at least in part by at least one discrete flow channel such that fluid can flow substantially unimpeded from one of the inlets to an outlet opening at another face of the stack. A layer of fluid pathways is defined by two opposing charged film layers at least one of which is a structured film layer. The flow channels have an average height of from 0.1 mm to 5 mm and an average width of from 0.05 mm to 50 mm and an average aspect ratio of from 0.5 to 10.

Abstract: A pleatable high efficiency non-woven, gas filtration media is provided. The media has an electrically charged air laid fibrous layer with a thickness between about 2 and about 35 mils, and a wet laid fibrous layer having a thickness of between about 5 and about 35 mils. The combined layers have, (a) a thickness of between about 10 and about 50 mils, (b) a stiffness of between about 200 and about 3500 mgs, (c) a Frazier of between about 10 and about 400 CFM, and (d) an &agr; of at least 15.

Abstract: To provide chargeable tow and a laminate thereof, which can be produced with no restriction by the production or processing method, and without troubles such as twining on a roll or single thread snapping caused by static electricity generated in the production steps. Tow, in which the value (D/W) obtained by dividing the total fineness of tow (D) by the tow width (W) is 1,000 to 8,000 dtex/mm, is produced by making a fiber-processing agent adhere thereto, preferably using a particular amount of the agent, wherein the agent has a particular structure and contains a polyoxyethylene higher fatty acid ester and a sorbitan fatty acid ester in a particular blending ratio.

Abstract: An electret is described that includes a surface modified polymeric article having surface fluorination produced by fluorinating the polymeric article.

Abstract: A process for the manufacture of a triboelectrically charged nonwoven, wherein a fiber blend made of polyacrylnitrile fibers with a titer of ≦1.7 dtex and of polyolefine fibers with a titer of ≦1.7 dtex is freed from lubricating agents and antistatic agents by washing, is dried down to a moisture content of <1% by weight and is carded on a longitudinal or randomizing card into a triboelectrically charged web with a mass per area unit of 15-80 g/m2. This web is taken off by two simultaneously running rolls and a transfer roll, so that the web is laid on to a conveyor in machine direction, and bonded directly inside a bonding set, the unbonded web being forwarded via 1 to 3 points of transfer only.

Abstract: A filter made of nonwoven fabric, paper or the like for gaseous media, having an electrically conductive coating made of a conductive substance of pulverizable materials, in particular from electrically conductive carbon-black particles and/or powdery metal particles or other pulverized materials, the carbon-black particles or metal particles being fixed to the filter fibers with the aid of binding agents, and the conductive coating being applied in a reticulated manner on the filtering layer.

Abstract: A filtration media is formed from at least one structured polymeric layer, wherein a structured surface is defined within the layer. Layers may be configured as a stack that has the structured surfaces defining a plurality of ordered inlets open through a face of the stack and corresponding ordered fluid pathways, thereby forming an ordered, porous volume. The ordered fluid pathways may be defined by a plurality of flow channels formed within the structured surfaces of the structured layers, or may be defined by a plurality of protuberances formed in an ordered pattern within the structured surfaces of the structured layers.

Abstract: A washable air filter for removing particles from the inlet air to a heating and/or air conditioning system formed of an assembly of a central polymeric pad containing actively charged charge control agents of a first polarity, a polymeric net containing a dispersion of charged charge control agents of a second polarity in the polymer on each side of the pad and a stiff, deformable metal or plastic grill on each side of the net to form an assembly which can be corrugated and placed in a perimeter frame. The charging is preferably accomplished as the assembly passes over the surface of a roller with a conductive surface.

Abstract: An electret filter media includes an additive or mixtures thereof that enhance the charge stability of the media. The filter media achieves acceptable alpha values for a range of filtration challenges without significant decay in alpha values over time. Preferred charge additives include fatty acid amides and mixtures thereof.

Abstract: An air-cleaning apparatus and air-cleaning method whereby air is cleaned with an air flow containing ions and ozone generated by corona discharge. The apparatus has a wind tunnel part including a trumpet-shaped member (3) having an opening at the bottom thereof and a cylindrical member (4) connected to the opening at the bottom of the trumpet-shaped member (3). The wind tunnel part has a titanium dioxide metal evaporated onto the surface thereof. A needle electrode (1) is placed in front of the trumpet-shaped member (3) of the wind tunnel part near an axis of the trumpet-shaped member (3). An annular electrode is formed on the inner surface of the wind tunnel part. A high-voltage generating unit applies a high voltage between the needle electrode (1) and the annular electrode (2). A housing (10) accommodates the needle electrode (1), the annular electrode (2) and the wind tunnel part and has an air inlet (11) on a side thereof closer to the needle electrode.

Abstract: A pleated filter is provided with electrically conductive fibrous material that releases ions to improve trapping efficiency. The edges of folded filter media are rendered emitting as by attaching conductive strings to the edges of the folds. The ends of the fibers in the strings are left exposed and, by applying high voltage on these strings, ions may be produced which charge dust particles to improve the filter's efficiency. Alternately, the pleated medium itself provides ion-emitting fiber ends along folded edges that have been rendered conductive.

Abstract: A photocatalytic filter having a coating layer formed in a thickness of 5 to 60 &mgr;m on a base material and including 5 to 60% by weight of ultraviolet ray-transmissible particles (such as glass particles or fibers) having a minor axis of 0.2 to 50 &mgr;m, 20 to 80% by weight of photocatalytical particles (TiO2) having an average particle size of 0.001 to 0.02 &mgr;m, 10 to 60% by weight of fine silica particles having an average particle size of 0.002 to 0.2 &mgr;m and optionally 0.2 to 20% by weight of a clay mineral material, preferably a portion of the ultraviolet ray-transmissible particles being exposed to the outside of the coating layer, exhibits a high air-cleaning activity, a high adhesion of the coating layer to the base material and a high durability in the air-cleaning activity.