Abstract:
A filter medium and frame therefore wherein the filter medium is treated by a novel adhesive comprised of a major portion by weight of an oil group consisting of vegetable, animal, or mineral oils and a minor portion of a preselected thickening material with the rigidity of the filter medium being obtained by sandwiching the filter medium between joined mating upstream and downstream frame members.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This is a continuation of co-pending application Ser. No. 09/633,922, filed Aug. 8, 2000, now U.S. Pat. No. ______ , which is a continuation-in-part of application Ser. No. 09/236,207, filed Jan. 23, 1999, now abandoned, both of which are incorporated herein by reference. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    The present invention relates to a unique and novel filter media and more particularly to a unique adhesive treatment for filter media and a mounting frame for such media.  
           [0004]    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.  
           [0005]    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 some past adhesives. In addition, the present invention provides a novel frame support for filter media including—but not limited to—filter media which can be coated with the novel adhesive herein described. The novel frame support also herein described, is efficient, economical, and straightforward in manufacture, use and assembly, providing desired firmness and stability characteristics to the novel treated filter media during filtering operations.  
           [0006]    Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    In accordance with the present invention, a novel medium for removing particulates from a fluid stream is provided. The filter medium comprises a porous fiber filter medium and an adhesive coating therefor selected from a preselected percentage mixture of a major portion of a pure oil group consisting of vegetable, agricultural, mineral or animal oils and a minor portion of a thickening material. In addition, a novel filter frame is provided for sandwiching filter medium, such as, but not limited to the novel filter medium herein, therebetween. The filter frame comprises a pair of substantially rigid fluid flow-through support frame members. At least one of the frame members includes spaced, normally extending male frame closing posts adapted to extend through the filter medium. The other frame member includes spaced female receptacles aligned with the closing posts to nestingly engage and close with the male frame closing post extremities.  
           [0008]    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. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0009]    Referring to the drawings which disclose one advantageous embodiment of the present invention including the novel and unique frame member in which the inventive media can be mounted:  
         [0010]    [0010]FIG. 1 is an exploded isometric view of the novel frame members prior to assembly as a frame;  
         [0011]    [0011]FIG. 2 is an enlarged, cross-sectional, view of a portion of the frame members of FIG. 1 disclosing in more detail, a male closing post and an aligned cooperative female receptacle arrangement;  
         [0012]    [0012]FIG. 3 is an isometric view of two layers of fibrous filter medium coated with an inventive adhesive material and including a frame arrangement (only one frame member being shown) in accordance with the structure of FIGS. 1 and 2;  
         [0013]    [0013]FIG. 4 is a filtration efficiency representative graph comparing the filtration efficiency, at particle sizes of more than 0.3 micrometers of a filter medium treated with a herein disclosed inventive adhesive with the filtration efficiencies of four other filter media, three filter media of which were each treated with the same adhesive amounts of one of three known commercial adhesives and a fourth filter medium which was not treated. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]    Referring to the exploded isometric view of FIG. 1, a filter frame  2  is disclosed. Frame  2  as disclosed is geometrically configured and sized to receive one or more sheets of filter medium therebetween and is here shown as being of rectangular shape. It is to be understood that frame  2  can be geometrically configured to be any one of a number of other geometric configurations, depending on the structural environment in which it is to be assembled. Frame  2  includes a pair of substantially rigid fluid flow-through support frame members or panels  3  and  4  which can be formed from any one of a number of suitably rigid materials such as, but not limited to, woods, metals, cardboards or plastics. As shown in FIG. 1, the rectangular frame panels  3  and  4  are configured to be in mating and facing relation to each other and include central grid bars  6  and  7 , providing two (2) flow-through areas. At least one of the frame members or panels  3  and  4  can include normally extending frame male closing posts  8  which are adapted to extend through the filter medium sheet or sheets to be sandwiched between the panels. The opposite mating panel can be provided with female receptacles  9 , which are spaced and aligned with posts  8  to nestingly engage with and close with the post extremities. It is to be understood that anyone of a number of mating male spaced post and aligned female receptacles therefor can be utilized and distributed along either or both of the panels as needed. Further, any number of grid bars can be employed to provide divided flow-through passages, depending upon the size and configuration designs of associated structure.  
         [0015]    Referring to FIGS. 1 and 2 of the drawings, it can be seen that in the disclosed embodiment, frame member or panel  4  is provided with nine (9) spaced male posts  8  and frame member or panel  3  is provided with nine (9) spaced and aligned female receptacles  9 . As can be seen in enlarged FIG. 2, each male post  8  is provided with a flexible, arrow-shaped tip  11  contoured and shaped to engage with an inwardly sloping entrance shoulder  12  of an aligned female receptacle  9  to be compressed to pass through an aperture  13  and to then expand and lockingly nest with a substantially flat enlarged accommodating recess  14  of female receptacle  9 . Thus, as can be seen in FIG. 3 of the drawings, two stacked and aligned sheets of filter medium  16  and  17  can be readily assembled to form as filter frame  2  with the media sandwiched between frame members or panels  3  and  4  and with the male posts  8  and female receptacles  9  in locking engagement.  
         [0016]    In accordance with still another feature of the present invention, each of the filter medium sheets  16  and  17  can be coatingly treated with one or more of the novel adhesive oils 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 any one 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 preselected percentage mixture of a major portion of a pure oil group and a minor portion of preselected thickener material, along 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 preselected thickener material serves as an oil thickener to increase flow resistance. The adhesive coating mixture comprises a pure oil group in the range of approximately 90% to 100% percent by weight of said mixture or pure oil and a thickener in the range of approximately 0% to 10% by weight of the mixture and advantageously an oil group of approximately 95% by weight of the mixture and a silica of approximately 5% by weight of the mixture. The oil of the group, including the thickener, can desirably have a viscosity flow rate in the range of 0.5 to poise and advantageously approximately 12.5 poise and can be one or a combination of pure 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 pure mineral oil advantageously with a molecular formula CH 3 (CH 2 ) n CH 3 , commercially available under the trade name “Avatech”, from Avatar Corporation, 500 Central Avenue, University Park, Ill., 60466. The thickener of the minor portion can be chosen from the group consisting of silica, treated clay, inorganic powder or a polymeric material or a preselected mixture by weight of the same, with the mixture having a viscosity in the range of 0.5-500 poise, advantageously at approximately 12.5 poise, and advantageously can be a silica material. Referring to the representative efficiency graph in FIG. 4 of the drawings, curves are shown, which plot and compare the relative efficiencies of five (5) identical filter media. Three (3) of the curves represent identical media which were treated, as above described, separately with three commercially available different adhesives, namely a commercial adhesive known as chlorinated paraffin and designated by the rectangular mark and reference numeral  18 , a commercial adhesive known as polybutene and designated by the triangular mark and reference numeral  19 , and, a commercial adhesive known as petroleum hydrocarbon and designated by the cross mark and reference numeral  21 . A fourth curve designated by the diamond mark and reference numeral  22  represents an identical filter media which was untreated and which does, in fact, show the lowest efficiency. The fifth curve designated by the circular mark and reference numeral  23  shows the highest efficiency of all. It was treated by an inventive adhesive of a mixture of ninety-five (95) percent by weight of soybean oil and five (5) percent by weight of silica. Although not demonstrated by graphs for other oils in the inventive group of oils and oil thickeners, similar efficiency results to that of the representative efficiency graph would be obtained.