Patent Publication Number: US-2022233981-A1

Title: Air Filter Inactivation of Viruses and Micro-organisms

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to HVAC systems, and more particularly, to remediation of biological contaminants in breathable air used in occupied structures. 
     Prior HVAC systems have been generally used to provide filtered air to buildings and the like. Unwanted viral and microbial populations entrained in such air can be a health hazard, either directly through respiratory infection or tissue contact with building occupants, or indirectly through contamination of products made and/or used in such buildings which later come into contact with persons outside of the building. Prior HVAC systems have been suggested to attempt to remove such biological health hazards, but such systems have not been as effective as desired for a variety of reasons, particularly when dealing with COVID-19 situations. 
     Further, this invention relates to manufacturing processes for HVAC filters. Previously, it has been known to use non-woven fibers in such filters and to treat such fibers with various chemicals and materials. However, such treatments have been limited by the chemical natures of the materials used because, for example, certain chemicals cannot be mixed together for combined application to the fibers without adverse chemical interactions. 
     OBJECTIVES OF THE INVENTION 
     Accordingly, a primary objective of the invention is to provide improved HVAC filtration and processes for making air filters. These improvements include providing such filtration and filters which:
         a. are less inexpensive to manufacture, install, and maintain,   b. reduce biological contamination in the processed air,   c. provide filter versatility,   d. accommodate a variety of different pre-existing air filtration systems, and   e. increase user convenience and safety.       

     SUMMARY OF THE INVENTION 
     These and other objectives of the present invention are achieved by the provision of a process for removing viruses and micro-organisms from building air by inactivation of those biological elements within an HVAC filter having exuding halogenated material therein. The filter for the HVAC systems has the exuded halogenated material applied with a tackified material via a sequential spraying operation prior to heat curing either of those materials. The filter can subsequently be formed with other laminated materials for increased efficiency, and pleated for use in the HVAC system. Both porous and non-porous substrate fibers can serve as the substrate web for the exuded halogenated material, preferably processed as a non-woven web during air filter fabrication. 
     Other objects, advantages, and novel features of the present invention will become readily apparent from the following drawings and detailed description of certain preferred and alternative embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  shows schematically the process for creation of a preferred air filter for use in the process of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention provides for inactivation of viruses and micro-organisms by inactivation of those contaminants in the air filter apparatus of a HVAC system for a building or like structure, whether fixed or mobile. This invention is suitable for use in a wide variety of conventional HVAC systems, but particularly where non-woven fibrous air filter materials are used to filter the output air. Exuding halogenated material is applied to those air filter materials, together with a tackified emulsion, to contact with and retain the undesired contaminants within the air filter. The specific chemicals selected for use in the exuding halogenated material and the tackified emulsion will, preferably also inactivate the specific contaminants of concern, such as COVID-19. 
     With reference to  FIG. 1 , a preferred process for creating the air filter is to select a plurality of suitable fiber types, such as two or three Auriga or Stein fiber types of 1.5 to 2 inches, and blend the fibers together at Stage FB. Thereafter, the fibers can be blended and pre-opened in the usual manner, such as with a VO K mixer and Garrett/MTO apparatus at Stage W to create the form of the desired web. Thereafter, any desired needling can be done, such as by a Hunter Board, at stage N. 
     At that point, the web is ready for sequential “wet spraying” at Stages S 1  and S 2  to applying first the tackified emulsion and then the exuding halogenated material to the top side of the web. An example of such an emulsion would be commercially available BASF surfactant LF711.An example of such an exuding halogenated material would be Brominated Vegetable Oil. Preferably, Stage S 1  sprays the material with sufficient pressure and volume as to drive that emulsion down thoroughly into the web. Thereafter, and prior to allowing the emulsion to fully dry, Stage S 2  applies the material with sufficient pressure and volume that it is deposited as a surface layer to the web. The specific materials used at Stages S 1  and S 2  can be adapted to target specific contaminants of particular concern for a given application of the present invention. 
     At that point, the web is subjected to heat curing, at least on its top side. The curing preferably occurs at a temperature between 240 and 350 degrees F. and for a duration of 30 to 60 seconds as the web is moved through the heating area, H 1 . Thereafter, a similar spray process is applied to the opposite or underside of the web at Stages S 3  and S 4 , using the same respective spray materials, unless it is preferred to sensitize the web to different types of contaminants on that side of the web. Alternatively, the back side of the web can be treated with a binder spray-on material or the like to assist in laminating other layers to the web, in a given application, according to conventional processes. Subsequent heat treating stages H 2  and H 3  are applied to the web, as needed for particular formulations of the subsequent spraying Stages S 3 , S 4  and the like. After heat treatment, any desired laminating and/or final processing, such as pleating, cutting, folding, printing, or the like of the web, can be implemented, as indicated as Stages La and FP, such that the web is preferably formed and dimensioned as an air filter of conventional size and shape for placement into conventional HVAC systems or any desired subsequent HVAC system. 
     After this specially treated air filter is so produced, it is preferably installed into a HVAC system which provides for air filtration at a MERV (Minimum Efficiency Reporting Value test method ASHRAE 52.2, 2017) of between 9 and 20. During operation of that HVAC, contaminated air is passed through that air filter, thus completely the process of the present invention. 
     Although the present invention has been shown and described herein with respect to certain preferred embodiments and alternative configurations, those were by way of illustration and example only. For example, in especially preferred embodiments, the heat treatment of the web can be provided by a multi-pass oven. Also, while sequential spraying stages are shown above for application of the two “wet” materials, the present invention expressly contemplates that these materials can also be applied via dip coating and curtain coating to the web. Further, while a web of fibrous, non-woven material is discussed above as a suitable substrate for these materials, the present invention contemplates that other substrate materials can be similarly employed as needed for given applications. Further still, while polyester fibers have been described above or the web, the present invention contemplates use of fibers formed from other materials, as needed for given applications. Accordingly, the spirit and scope of the present invention is intended to be limited only by the terms of the appended claims.