Patent Application
20080190772
The present invention is directed to apparatuses and methods for filtering air, and especially to apparatuses and methods for filtering air using a plurality of electrically conductive filter elements.
Manufacturers of equipment employing air filtration continually seek structures and methods for air filtration that are less expensive to make an use while maintaining a desirable level of particle removal from filtered air. Multiple filter elements arranged within a flow of filtered air are known to aid in removing particles. Other techniques include ionizing particles and establishing a potential across a permeable filter entrapping element.
Efficiency of air filtering apparatuses and processes may be measured in terms of energy used for effecting a particular level of particle removal. Energy used may be measured by pressure drop across a filtering apparatus; more energy is required to drive a fan at a higher speed to effect a greater pressure drop.
Another factor affecting cost of manufacture of a filtering apparatus is the number of elements contained in the filtering apparatus. Increasing the number of filter elements in a filtering apparatus increases the cost of manufacturing the filtering apparatus.
There is a need for an apparatus and method for removing particles from air that is efficient in operation and inexpensive to manufacture.
An electrically enhanced filter apparatus for removing particles from air passing through the filter in a flow path from an upstream locus to a downstream locus includes: a plurality of electrically conductive particle-permeable electrodes situated in the flow path. A first electrode is an electrically conductive permeable electrode situated substantially at the upstream locus. A second electrode is an electrically conductive permeable electrode situated downstream of the first electrode in spaced relation with the first electrode. The second electrode is coupled with a voltage source sufficient to effect ionizing of the particles passing though the second electrode. A third electrode is situated downstream of the second electrode in spaced relation with the second electrode. A fourth electrode is situated downstream of the third electrode in spaced relation with the third electrode. A particle-permeable filter element is situated between the third electrode and the fourth electrode.
A method for removing particles from air passing through a filter in a flow path from an upstream locus to a downstream locus includes: (a) providing a plurality of electrically conductive particle-permeable electrodes situated in the flow path; (b) situating a first electrically conductive permeable electrode of the plurality of electrodes substantially at the upstream locus; (c) situating a second electrically conductive permeable electrode of the plurality of electrodes downstream of the first electrode in spaced relation with the first electrode and coupled with a voltage source sufficient to effect ionizing of the particles passing though the second electrode; (d) situating a third electrically conductive permeable electrode downstream of the second electrode in spaced relation with the second electrode; (e) situating a fourth electrically conductive permeable electrode downstream of the third electrode in spaced relation with the third electrode; and (f) situating a particle-permeable filter element between the third electrode and the fourth electrode.
It is, therefore, a feature of the present invention to provide an apparatus and method for removing particles from air that is efficient in operation and inexpensive to manufacture.
Further features of the present invention will be apparent from the following specification and claims when considered in connection with the accompanying drawings, in which like elements are labeled using like reference numerals in the various figures, illustrating the preferred embodiments of the invention.
The apparatus of the present invention is embodied in its preferred embodiment in a four-electrode filtration apparatus. Preferably the electrodes are electrically conductive permeable electrodes that are arrayed, from upstream to downstream in the flow of air being filtered, in a first expanded metal electrode, a wire ionizing array, a second expanded metal electrode, a permeable filter element and a third expanded metal electrode. Preferably, the first expanded metal electrode is grounded and the wire ionizing array is a high voltage electrode. By way of example and not by way of limitation, voltage on the wire ionizing array may be 15 kiloVolts, 17.5 kiloVolts or 20 kiloVolts.
Preferably the first electrode pair—the first expanded metal electrode and the wire ionizing array—cooperate to ionize and charge particles in the treated air flowing through the filter apparatus. Filter elements adjacent to the filter element—the second and third expanded metal electrodes—cooperate to aid in polarizing the filter medium to enable a stronger attraction between particles in the air and the filter medium.
In some embodiments of the present invention, electrodes adjacent to the filter medium may establish an electric field across the filter medium. In some embodiments of the present invention, selected electrodes may be permitted to electrically float. Floating electrodes are not coupled with an electric potential, or with an electrical ground, but are allowed to assume an induced voltage or charge. Floating electrodes have an induced charge polarity that is opposite of the polarity of the closest high voltage or grounded electrode. A floating electrode can impart a charge to particles or can aid in filter polarization without the cost of requiring that an apparatus generate additional voltage or current to establish a charge for effecting polarization.
Array 20 also includes a second filter element 24 situated downstream of first filter element 22 in spaced relation with first filter element 22. Second filter element 24 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 10 generally unimpeded absent any electrical influence by second filter element 24. In its preferred embodiment second filter element 24 is configured as a wire ionizing array coupled with a voltage source 40. Preferably voltage source 40 imparts sufficient voltage to second filter element 24 to substantially ionize particles in air traversing second filter element 24.
Array 20 also includes a third filter element 26 situated downstream of second filter element 24 in spaced relation with second filter element 24. Third filter element 26 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 10 generally unimpeded absent any electrical influence by third filter element 26. In its most preferred embodiment third filter element 26 is configured as an expanded metal electrode.
Array 20 also includes a fourth filter element 28 situated downstream of third filter element 26 in spaced relation with third filter element 26. Fourth filter element 28 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 10 generally unimpeded absent any electrical influence by fourth filter element 28. In its most preferred embodiment fourth filter element 28 is configured as an expanded metal electrode.
Array 20 also includes a fifth filter element 30 situated between filter elements 26, 28. Fifth filter element 30 is preferably a permeable filter element configured of a filtering material. By way of example and not by way of limitation, fifth filter element 30 may be configured using paper material, fiberglass material or another material known to those skilled in air filter design for effecting a filtering action regarding particles in air traversing the filter material.
In the embodiment of the apparatus of the present invention illustrated in
Array 120 also includes a second filter element 124 situated downstream of first filter element 122 in spaced relation with first filter element 122. Second filter element 124 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 110 generally unimpeded absent any electrical influence by second filter element 124. In its preferred embodiment second filter element 124 is configured as a wire ionizing array coupled with a voltage source 140. Preferably voltage source 140 imparts sufficient voltage to second filter element 124 to substantially ionize particles in air traversing second filter element 124.
Array 120 also includes a third filter element 126 situated downstream of second filter element 124 in spaced relation with second filter element 124. Third filter element 126 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 110 generally unimpeded absent any electrical influence by third filter element 126. In its most preferred embodiment third filter element 126 is configured as an expanded metal electrode.
Array 120 also includes a fourth filter element 128 situated downstream of third filter element 126 in spaced relation with third filter element 126. Fourth filter element 128 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 110 generally unimpeded absent any electrical influence by fourth filter element 128. In its most preferred embodiment fourth filter element 128 is configured as an expanded metal electrode.
Array 120 also includes a fifth filter element 130 situated between filter elements 126, 128. Fifth filter element 130 is preferably a permeable filter element configured of a filtering material. By way of example and not by way of limitation, fifth filter element 130 may be configured using paper material, fiberglass material or another material known to those skilled in air filter design for effecting a filtering action regarding particles in air traversing the filter material.
In the embodiment of the apparatus of the present invention illustrated in
Filter elements 122, 126 are coupled with a ground 144 to permit filter elements 122, 126 to cooperate with filter elements 124, 128 in establishing desired electric fields within filter apparatus 110.
A floating electrode such as fourth filter element 128 may assume an induced voltage or charge having an induced charge polarity that is opposite of the polarity of the closest high voltage or grounded electrode. In the case of filter apparatus 110 (
Array 220 also includes a second filter element 224 situated downstream of first filter element 222 in spaced relation with first filter element 222. Second filter element 224 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 210 generally unimpeded absent any electrical influence by second filter element 224. In its preferred embodiment second filter element 224 is configured as a wire ionizing array coupled with a voltage source 240. Preferably voltage source 240 imparts sufficient voltage to second filter element 224 to substantially ionize particles in air traversing second filter element 224.
Array 220 also includes a third filter element 226 situated downstream of second filter element 224 in spaced relation with second filter element 224. Third filter element 226 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 210 generally unimpeded absent any electrical influence by third filter element 226. In its most preferred embodiment third filter element 226 is configured as an expanded metal electrode.
Array 220 also includes a fourth filter element 228 situated downstream of third filter element 226 in spaced relation with third filter element 226. Fourth filter element 228 is preferably an electrically conductive permeable electrode configured to pass particles in air traversing filter apparatus 210 generally unimpeded absent any electrical influence by fourth filter element 228. In its most preferred embodiment fourth filter element 228 is configured as an expanded metal electrode.
Array 220 also includes a fifth filter element 230 situated between filter elements 226, 228. Fifth filter element 230 is preferably a permeable filter element configured of a filtering material. By way of example and not by way of limitation, fifth filter element 230 may be configured using paper material, fiberglass material or another material known to those skilled in air filter design for effecting a filtering action regarding particles in air traversing the filter material.
In the embodiment of the apparatus of the present invention illustrated in
Filter element 222 is coupled with a ground 244 to permit filter element 222 to cooperate with filter element 224 in establishing desired electric fields within filter apparatus 210.
Floating electrodes such as third filter element 226 and fourth filter element 228 may assume an induced voltage or charge having an induced charge polarity that is opposite of the polarity of the closest high voltage or grounded electrode. In the case of filter apparatus 210 (
Method 300 continues with situating a first electrically conductive permeable electrode of the plurality of electrodes substantially at the upstream locus, as indicated by a block 306.
Method 300 continues with situating a second electrically conductive permeable electrode of the plurality of electrodes downstream of the first electrode in spaced relation with the first electrode and coupled with a voltage source sufficient to effect ionizing of the particles passing though the second electrode, as indicated by a block 308.
Method 300 continues with situating a third electrically conductive permeable electrode downstream of the second electrode in spaced relation with the second electrode, as indicated by a block 310.
Method 300 continues with situating a fourth electrically conductive permeable electrode downstream of the third electrode in spaced relation with the third electrode, as indicated by a block 312.
Method 300 continues with situating a particle-permeable filter element between the third electrode and the fourth electrode, as indicated by a block 314. Method 300 ends at an END locus 316.
It is to be understood that, while the detailed drawings and specific examples given describe preferred embodiments of the invention, they are for the purpose of illustration only, that the apparatus and method of the invention are not limited to the precise details and conditions disclosed and that various changes may be made therein without departing from the spirit of the invention which is defined by the following claims:
