Abstract:
A personal air purifier employs tapered reticulated foam semi-cylinders sized to be closely received within a user&#39;s nostrils through slight expansion of the nostril. The semi-cylinders include a flat base and a spherical shaped surface at a distal end with flattened surfaces circumferentially spaced about the semi-cylinder for enhanced fit within the nostril. The flat base of the two semi-cylinders is connected by an integral flexible band which extends across the end of the septum of the user&#39;s nose to preclude over-insertion and aid in removal.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to the field of air filtration and, more particularly, to a semi-spherically topped substantially cylindrical interconnected reticulated foam plug set for insertion into the user&#39;s nostrils for air filtration. 
   2. Description of the Related Art 
   The human body is insulted by many airborne contaminants including allergens, animal dander, house dust, mites, construction dusts, ragweed pollens, rye grass pollens and other environmental pollutants. The National Institute of Allergy and Infectious Diseases estimates that 35 million Americans are plagued by upper respiratory symptoms that in many cases are allergic reactions to the airborne contaminants that are breathed every day. This is a global problem as a recently published study in the European Respiratory Journal suggested that workplace exposure may cause as much as 31% of all cases of chronic obstructive pulmonary disease, which kills more than 100,000 Americans each year. 
   The respiratory system of the human body is the main route for entry of contaminants such as dusts and pollens. The respiratory system includes the nose and mouth, trachea, bronchi (branching airways), and alveoli (interior surface of the lungs). The human anatomy is designed to process the airborne impurities through the nose so that the air is purified, warmed and humidified before it reaches the lungs. The hairs and mucous membranes inside the nose normally trap large particles of dirt and allergens. The trapped dirt particulate are eventually blown out the nose or coughed up. Allergens, trapped by the mucous membranes sometime cause a reaction where histamine and other chemicals are released causing swelling and nasal congestion. 
   Under normal conditions, particulate that bypass the nasal hairs are trapped by the fluids produced in the mucous membranes of the windpipe and bronchi and moved to the mouth by the cilia (hairlike projections that move in unison). There the particulate and dust are coughed up and spit out or swallowed. 
   The human respiratory system can be overwhelmed if its capacity to process airborne impurities is exceeded. Given that healthy lungs take two to three days to clear themselves after overloading, it is evident that a personal air purifier to help remove inhaled allergens and particulates has great public value. 
   Personal Air Purifiers generally fall into two categories: Type 1—those which cover both the nose and mouth and type 2—those which cover a portion of the nose or are insertable in the nostrils. 
   Regarding type 1, those that cover both the nose and mouth are uncomfortable because they trap heat and cause the face to sweat, especially during heavy exertion. They also make eating and drinking impossible, make talking difficult and make the use of spectacles both uncomfortable and dangerous due to fogging. 
   Regarding type 2, the prior art teaches a variety of nostril insertable filters or partial nose covering gloves, for example, those disclosed in U.S. Pat. Nos. 4,030,491; 4,220,150; 4,573,461; 5,117,820; 5,568,808; 5,636,629; 5,740,798; 5,890,491; 6,216,694 B1 and D451,193 S. 
   U.S. Pat. No. 4,030,491 to Mattila teaches the use of a pair of containers with separate filters and covers. Unlike the present invention there are seven small, difficult-to-handle pieces, the plastic housings are not conformable to the inside of the nose and it is difficult for the housings to suit different size nostrils. The difficulty in establishing a proper fit facilitates blowby, the passage of unfiltered air between the outside of the housing and the inside of the nose. Mattila also teaches that the housings are reusable possibly leading to contamination by biologics which may be present in the nose including rhinoviruses, adenoviruses, (which lead to respiratory infection), parainfluenza, and bacteria. 
   U.S. Pat. No. 4,220,150 issued to King teaches the use of a clip that clamps the interior septum wall as a structure to support two plastic, ball mounted filter cups. Unlike the present invention the use of a septum clip is uncomfortable and may be impossible to use in the event of a deviated septum or other physiological aspect. King teaches that the filter cups swivel to fit the interior of the nose. The cups may not filter efficaciously if they are not exactly aligned facing the incoming air. If not properly in position, blowby may occur reducing filter efficiency drastically. All of the assemblage that King teaches including the structure necessary to hold the septum clip and filter housing drastically reduces the nostril air flow area thereby creating a higher breathing resistance. 
   U.S. Pat. No. 4,573,461, Lake, teaches the use of an oblong ellipsoid-shaped solid material to block off the nasal cavities for a specific time and then a porous material to function as a filter. Unlike the present invention the solid insert is used for a period of 30 minutes or more to block off the airflow through the nose and then the solid shapes are removed and the porous material shapes inserted. The use of a solid insert does not allow air to pass into the lungs and hence does not provide an air purifying effect. 
   U.S. Pat. No. 5,117,820, Robitaille, teaches the use of two cylindrical synthetic spongy materials with one black end on each cylinder, said cylinders being compressed by the application of vacuum prior to inserting in the nostrils. Unlike the present invention, a source of vacuum is required to compress the material prior to insertion, the spongy material is not identified, there is no physical restraint to prevent over or under insertion into the nostril and no characteristic to determine where within the nostril it should be placed. 
   U.S. Pat. No. 5,568,808 issued to Rimkus teaches the use of two separate housings each containing a filter material. Said housing is inserted in each nostril and a flutter valve forms a seal with the lower portion of the nostril. The intent is to force inhalation air to pass through the filter media rather than blow by the housing while exhalation air bypasses the housing and escapes through the flutter valve. Unlike the present invention it is difficult to position the housing to seal on the exterior edges of the nostril, there are four small, difficult-to-handle pieces, the housings are not conformable to the inside of the nose and it is difficult for the housings to fit different size nostrils thereby facilitating blowby. Rimkus also teaches that the housings may be reusable possibly leading to contamination which may be present in the nose including rhinoviruses, adenoviruses, parainfluenza, pollens and bacteria. 
   U.S. Pat. No. 5,636,629 issued to Patterson, Jr. teaches the use of a nasal glove consisting of filter material circumscribed with a flexible material which is bent to conform with the shape of the exterior of the nose to hold the glove in place. Unlike the present invention that seals around the interior nasal vestibule, there is no sealing at the juncture of the nostril and upper lip thereby allowing air to bypass the filter media. The filter media and efficacy are not well described and it is difficult for the housings to fit different size noses thereby facilitating blowby at the top and sides of the nose. 
   U.S. Pat. No. 5,740,798 issued to McKinney teaches an air filter worn over the end of the nose that consists of a filter element which is preferably made of a thermal fleece or a thermal undergarment material which is held to the nose by a combination of an elastic strand and adhesive strips. Unlike the present invention, which seals inside the nasal vestibule, it is extremely difficult to seal airflow to the exterior nose with elastic bands thereby facilitating blowby. McKinney also teaches that a thermal undergarment material is a suitable filter material but does not identify the efficacy of such undergarment for filtration applications. 
   U.S. Pat. No. 5,890,491 issued to Rimkus, teaches that the flapper valve of U.S. Pat. No. 5,568,808 is not efficacious and that the nose filters housing and flange becomes fixedly attached inside the nostril through an adhesive component. Unlike the present invention the use of an adhesive on the sensitive membranes of the nose could be an irritant as well as painful when the housings are removed. Rimkus also teaches that the filter element fits inside the housing and is disposable. Unlike the present invention the housings are not conformable to the inside of the nose, it is difficult for the housings to fit different size nostrils thereby facilitating the passage of air between the outside of the housing and the inside of the nose. Rimkus also teaches that although the filter media is disposable, the housings are reusable possibly leading to contamination that may be present in the nose including rhinoviruses, adenoviruses, parainfluenza, pollens and bacteria. 
   U.S. Pat. No. 6,216,694 B1 issued to Chen teaches an insertable, conical, hollow nose plug with two separate active carbon air filters in the proximal (exterior) end of each conical hollow. Unlike the present invention, the filter media is placed only at the proximal end of the hollow cones and consequently is of small volume and therefore has a small contaminant handling capacity. The two separate filters must be sized for the proximal end of the hollow cone and the description of the filter media is unclear. Chen also teaches that the distal (interior) end of the conical tube may have a slanted plane and a tapered conical shape. It may be difficult to align the plane to the nasal bridge as the planes are not visible when inserted in the nose. The sharp plane may impact the sensitive areas of the inside of the nose causing irritation and discomfort while the tapered distal end may restrict airflow leading to an increase in breathing resistance. 
   U.S. Pat. No. D451,193S issued to McCormick, teaches of a shape for an insertable nasal filter whereby the filter elements are inserted into the housings. Unlike the present invention, the plastic housings are not conformable to the inside of the nose, it is difficult for the housings to fit different size nostrils thereby facilitating the passage of air between the outside of the housing and the inside of the nose. McCormick teaches that there are holes on the distal (interior) end of the housing. The total area of the holes in the distil side of the housing as compared to the proximal side is much less causing a reduction in air flow and corresponding increase in air bypassing the filter. In addition, reusable filter housings can lead to contamination that may be present in the nose including rhinoviruses, adenoviruses, parainfluenza, pollens and bacteria. 
   None of the above referenced inventions either singly or in concert is seen to describe and explain the present invention. 
   A desired aspect of a personal air purifier is to provide a method for purifying the air inhaled through the nose by providing a reticulated foam filter shaped to be soft and gentle to the interior of the nose while effectively preventing airborne contaminates such as allergens, animal dander, house dust, mites, construction dusts, ragweed and rye grass pollens and many environmental pollutants from entering the respiratory system. 
   Unlike previous inventions, where the filter media is a separate piece affixed to an assembly or inserted into a housing, it is desirable that the purifier consists of a single filter material molded into a shape that can be easily and safely inserted into and removed from the interior of the nose and nostrils. A unitary design provides the maximum surface area and volume for maximum airflow and filter efficacy. 
   Another desirable feature of a new and improved personal air purifier is that when fully seated within the nostrils its appearance will be aesthetically pleasing. 
   It is further desirable to provide a personal air purifier that will remain in place during eating, drinking, talking and heavy exertion but may be expelled in the event of an explosive sneeze. 
   Additionally it is desirable to provide a personal air purifier that is easily manufactured, and intended for daily use thereby minimizing the opportunity to reinsert in the nose a unit contaminated with viruses, bacteria and allergens. 
   It is also desirable to provide a simple, low cost, disposable, portable air purifier that can be economically used by all members of society. 
   It is also desirable to utilize the natural ability of foam to expand, fill and form the nostril area thereby sealing the purifier within the nostrils, eliminating blowby and providing maximum filtering area. 
   Further, it is desirable to utilize the inherent ability of the foam to apply gentle pressure to expand the outer nasal wall tissues from the septum structures thereby providing nasal dilation, increased air flow and subsequent filtering efficacy. 
   Still further, it is desirable to provide a personal air purifier of the depth filter type which will capture and hold contaminates by providing a tortuous path for the air flow to follow as it passes through the filter media. 
   SUMMARY OF THE INVENTION 
   The present invention consists of two semi-cylinders of dielectric reticulated foam filter media with a spherical shape on the distal (interior nose) end and a flat surface on the proximal end joined to each other at the proximal end with a thin flexible band. The thin flexible band is integrally molded with the semi-cylinders and is made from the same material and at the same time as the semi-cylinders. 
   The distal, spherical shaped end of each semi-cylinder is intended to be inserted in the nostril and located just inside and within the nasal vestibule. The spherical end guides the air purifier into position and prevents damage to delicate nasal membranes. The proximal end is tucked in within the nasal vestibule just behind where the ala of the nostril narrows. The flexible band prevents overinsertion of one or both of the semi-cylinders and serves as a handle to remove the air purifier from the nose. 
   The reticulated foam is a dielectric material that upon exposure to the air stream formed during the inhalation of air into the nostrils will generate an electrostatic charge that is capable of attracting and holding micron sized particulate and allergens within the foam intricacies of the filter material. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
       FIG. 1  is a top, front, left side perspective view of the personal air purifier of the present invention; 
       FIG. 2  is a front elevation view of the air purifier of  FIG. 1 , the rear view being a mirror image thereof; 
       FIG. 3  is a right side elevation view of the air purifier of  FIG. 1 , the left side elevation being a mirror image thereof; 
       FIG. 4  is a top plan view of the air purifier of  FIG. 1 ; 
       FIG. 5  is a view of the personal air purifier of the present invention inserted in the nostrils; and, 
       FIG. 6  is an elevation section view of the personal air purifier of the present invention inserted in the nostrils. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings,  FIG. 1  shows an embodiment of the invention that incorporates two semi-cylindrical shapes  10  of the same nominal diameter, which have at each distal end a spherical shape  12  to match and blend with the nominal semi-cylindrical diameter and at each other proximal end a base  14  with a flat surface whose plane is perpendicular to the cylinder axis. A thin, strong, flexible band  16  made of the same material as the semi-cylinders joins the semi-cylindrical shapes. The entire assembly is made from the same dielectric material, reticulated foam of the polyurethane or silicone chemical family and of the polyether or polyester category. 
   The manufacturing process for the present invention consists of first producing the foam by a chemical reaction process and then removing the cell walls within the foam by a thermal or chemical process thereby producing reticulated foam. The reticulated foam consists of a three dimensional matrix with voids and intricacies within a skeletal structure. 
   The reticulation process removes the cell walls, leaving only a structure of skeletal strands and voids. This makes the reticulated foam exceptionally porous and permeable but with many particulate catching strands and great contaminate holding capacity within the void spaces. 
   The reticulated foam manufacturing process is well understood by those skilled in the field, such as Foamex Inc., Linwood, Pa. and Lendell Manufacturing Inc., St. Charles, Mich. and results in a foam with consistent properties including density, tensile strength, tear strength, elongation, compression set, pore size (ppi—pores per inch) and dielectric nature. 
   The pores per inch specification relates directly to the air purifying efficaciousness, with a higher number relating directly to greater filtering ability and a greater breathing resistance. Current embodiments of the present invention are molded using reticulated foam of from 40 to 130 ppi so that the user may choose the best filtering characteristic based on individual need. 
   The reticulated foam is manufactured in large sections approximately six feet by four feet by one foot thick and then supplied to a foam fabricator skilled in the field such as Illbruck Inc., Minneapolis, Minn. For current embodiments, the fabricator slits the foam to the appropriate thickness of about 0.65 inch with a 48 inch by 72 inch sheet, saws the sheet to the handling blocks of about 12 inches and then die-cuts the blocks to produce individual precurser blocks of 1 inch by 2 inches by 0.65 inch which are then further die-cut to shape approximating the semicylinders and connecting band suitable as a preform for the molding process. The preform is then placed in a mold and, utilizing heat and pressure, the net shape of the product incorporating the present invention is produced including a felting step to compress the connecting band. The product is ready for use when it comes from the mold, no secondary manufacturing procedures are necessary. 
   Referring to  FIGS. 2 and 3 , there is a slight tapering of the semi-cylindrical shape from the proximal end or base  14  to the beginning of the spherical shape  12  providing a frustoconical section. This taper and the rounding at the vertex of the distal end of the spherical shape  12  allows for an easier insertion into the nose by guiding and gently expanding and forming the nostrils during insertion. 
   Referring to  FIGS. 2 and 4  the thin flexible band  16  is integrally molded to the proximal end  14  of the semi-cylindrical shapes and coincident with the centerline  18  that joins the centers of the faces at the base  14  of the proximal ends of both semi-cylindrical shapes  10 . The thin flexible band  16  has one surface in the same plane as the flat surface of the base  14  of the semi-cylindrical shapes and the other surface in a parallel plane a small distance away from the proximal end plane. 
   Referring to  FIGS. 2 ,  4  and  6 , the thin flexible band  16  is substantially thinner and narrower than the semi-cylindrical shapes thereby allowing great conformability to the exterior of the end of the nasal septum  20 . This conformity allows the base  14  of the proximal end of the semi-cylindrical shapes to be placed within the nasal vestibule just behind the narrowing of the nostril, the ala  22 . This restrains the personal air purifier so that it will not be dislodged by normal activities such as talking and eating, and still release under the pressures of an explosive sneeze. 
   Referring to  FIG. 3 , the distance from the flat surface of the base to the vertex of the distal end spherical shape  12  is approximately 110% of the average semi-cylindrical diameter and represents the total length of filtering media. In an exemplary embodiment the nominal diameter is 0.56 inches and the typical length is 0.62 inches. This length, times the semi-cylinder area provides an extremely large volume of filter media to trap and hold the particulate and allergens. 
   Referring to  FIG. 4 , the semi-cylindrical shape has a slightly flattened surface  30  on all four sides to better match the ovoid shape of the nostrils. The slightly flattened sides of the cylinders are spaced circumferentially around the frustoconical semi-cylinder and smoothly blended with the spherical shape  12  to assure a gentle yet retained fit within the nostrils. 
   Referring to  FIG. 5 , when installed the personal air purifier dilates the air passages in the nostrils  24  of the nose  26  to achieve a result similar to adhesive dilators that are affixed to the exterior of the nose. The foam expansion presents a larger filter surface area and as a consequence, lower face velocity across the filter and hence greater filter efficiency. 
   Referring to  FIG. 6 , the proximal ends of both semi-cylindrical shapes expand the nostril to conform to the shape, secure the personal air purifier to the nostril and assure that all the inhaled air passes through the reticulated air filter. The adaptability, softness and gentle expansion ability of the foam makes a nominal size suitable for many people. It is understood that the size of the personal air purifier may be varied to accommodate noses of other shapes and sizes. 
   Having now described the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications are within the scope and intent of the present invention as defined in the following claims.