1. Field of the Invention
The present invention relates to a unique and novel filter media and more particularly to a unique adhesive treatment for filter media.
2. Description of the Related Art
It has been long known in the filtering art that in order to provide a viscous impingement fibrous filter, a suitable adhesive medium should be used on the filter media. In this regard, attention is directed to. U.S. Pat. No. 4,608,173, issued to K. Watanabe et. al. on Aug. 26, 1986, which teaches a cationic polyacrylide coating on filter fibers; U.S. Pat. No. 5,124,177 issued to J. W. Kasmark, Jr. et. al. on Jun. 23, 1992, which teaches the use of one of several organic adhesives, such as an organic latex or acetate combined with activated odor removing particles, such as carbon or silica gel; U.S. Pat. No. 5,269,925, issued to T. E. Broadhurst on Dec. 14, 1993, which teaches the use of mineral coated fibers with grit added to provide surface roughness; U.S. Pat. No. 5,338,340, issued to J. W. Kasmark, Jr. et. al. on Aug. 16, 1994, which teaches the use of an organic, synthetic coating substance such as latex or an acetate combined with odor-removing activated particles, such as carbon or silica gel and the like, and, U.S. Pat. No. 5,525,136, issued to R. M. Rosen on Jun. 11, 1996, which teaches the use of oils, including vegetable oil, as a fibrous filter coating.
In accordance with the present invention, a new and useful fibrous filter media coating is provided which greatly improves filtration efficiency of certain particle sizes, which is comparatively inexpensive to make, install and use in a straightforward manner, which has a high system performance efficiency and integrity and, which minimizes liberation of respiratory irritating gases—an undesirable fault common to filtering gases or breathing air with some past adhesives. Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.
In accordance with the present invention, a novel medium for removing particulates from a gas stream is provided. The filter medium comprises a porous fiber filter medium and an adhesive coating therefore selected from a percentage mixture of a major portion of an oil group consisting of vegetable, agricultural, mineral or animal oils and a minor portion of a thickening material.
It is to be understood that various changes can be made by one skilled in the art in one or more of the several parts of the filter arrangements disclosed herein without departing from the scope or spirit of the present invention.
Referring to the drawings which discloses advantageous embodiments of the present invention:
In accordance with the present invention, filter medium sheets are coatingly treated with one or more of the novel adhesive oils in combination with a thickener of the present invention in order to obtain an improved filter efficiency and dust holding capacity with comparatively minimal initial resistance or static pressure drop across the treated filter media. The present invention provides for treating anyone of several known fibrous filter media such as, but not limited to, spun or chopped glass fibers, synthetic fibers or natural fibers. The filter media is coated with a novel adhesive coating selected from a percentage mixture of a major portion of an oil group and a minor portion of thickener material, and optionally with other additives such as anti-oxidants and flame retardants. The oil is chosen from the group consisting of vegetable, agricultural, mineral and animal oils. The thickener material serves as an oil thickener to increase flow resistance. The adhesive coating mixture comprises an oil group in the range of at least 90% by weight of said mixture or oil and a thickener in the range of at most 10% by weight of the mixture and advantageously an oil group of approximately 95% by weight of the mixture and a thickener of approximately 5% by weight of the mixture. The adhesive, including at least one oil of the group and a thickener, can desirably have a viscosity flow rate in the range of 0.5 to 500 poise and advantageously approximately 12.5 poise. The oil of the group can be one or a combination of oils extracted from soybean, corn, cotton seed, sunflower seed, safflower, canola, nut, sesame, olives, apricots, grape seeds, palm cedar, seal, mink, fish or other fatty oils or mineral oil advantageously with a molecular formula CH3(CH2)nCH3, commercially available under the trade name “Avatech”, from Avatar Corporation, 500 Central Avenue, University Park, Ill., 60466. The thickener of the minor portion has fumed silica and optionally additional thickener(s) chosen from the group consisting of treated clay, inorganic powder or a polymeric material or a mixture by weight of the same, with the thickener and oil having a viscosity in the range of 0.5-500 poise, advantageously at approximately 12.5 poise. Fumed silica is silicon dioxide with unique properties and is commonly added to liquids/coatings and solids to improve various properties, in this case the desired property is viscosity. Fumed silica has a chain-like particle morphology where the chains bond together in a liquid such as oil via weak hydrogen bonding. This property causes the fumed silica to be miscible in the oils disclosed herein and acts as a thickening agent therein. Fumed silica is typically produced with a continuous flame hydrolysis technique.
Referring to the representative efficiency graph in
Referring to the representative efficiency graph in
This is a continuation-in-part of co-pending application Ser. No. 10/669,963, filed Sep. 24, 2003, which is a continuation of application Ser. No. 09/633,992, filed Aug. 8, 2000, now U.S. Pat. No. 6,652,748, which is a continuation-in-part of application Ser. No. 09/236,207, filed Jan. 23, 1999, now abandoned, each of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | 09633922 | Aug 2000 | US |
Child | 10669963 | Sep 2003 | US |
Number | Date | Country | |
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Parent | 10669963 | Sep 2003 | US |
Child | 11246389 | Oct 2005 | US |
Parent | 09236207 | Jan 1999 | US |
Child | 09633922 | Aug 2000 | US |