Patent Publication Number: US-8978655-B2

Title: Integral valve effect respirator

Description:
RELATED APPLICATION 
     This application is a continuation in part of U.S. patent application Ser. No. 12,359,414 filed Jan. 26, 2009. Application Ser. No. 12,359,414 is based upon and claims priority from U.S. Provisional Application Ser. No. 61/023,246 filed Jan. 24, 2008. 
    
    
     FIELD 
     The disclosure relates to respirators, and more particularly to an integral valve effect respirator. 
     BACKGROUND OF THE DISCLOSURE 
     For individuals that are sensitive to airborne allergens, the severity of an allergic response is often not linearly proportional to the concentration of allergens in the air they breathe. Often there is little or no response unless exposure exceeds the particular threshold concentration that triggers a cascading symptomatic reaction. To prevent onset of such symptoms, it is therefore only necessary to limit exposure to some concentration below that threshold. Presently available personal respirators vary in both filtration efficiency and degree of user comfort, and these qualities are generally inversely proportional to each other. 
     Presently available personal respirators also commonly incorporate a one-way valve feature that allows free expiration, to reduce required breathing effort and to minimize inspiration of previously expired carbon dioxide. Such valve features add weight, bulk, and cost. 
     SUMMARY OF THE DISCLOSURE 
     A first objective is to provide a personal respirator with filtration efficiency sufficient only to maintain allergen exposure below an allergic reaction threshold. For users of a personal respirator a particular cause of discomfort is tension created by its holding strap and the resultant pressure of the mask edge on the user&#39;s face. A second objective is therefore to minimize these particular discomforts. A third objective is to provide a personal respirator whose entire body can efficiently function as a one-way valve, so that during expiration air can pass between the periphery of the mask and the user&#39;s face. A last objective is to mitigate eyeglass fogging by directing such peripheral expiration flow downwards. 
     This respirator is an adjunct for the management of allergies that can complement oral medications and immunotherapy. It provides an alternative to avoidance. It will serve a great need for people with allergies and/or asthma, people living in environments with heavy pollution, and those who frequently travel by commercial aircraft. It is a device that is beneficial to a user&#39;s overall health. 
     In an embodiment the respirator comprises a nose and mouth covering porous filter body and a flexible restraining device arranged so that the body may pivot in its vertical plane of symmetry about its nose contact portion, and the restraining device attaches to the body at positions where its restraining force imparts torque in the body about said nose contact portion so that the chin contact portion of said body bears against the user&#39;s chin. In use, the resulting chin contact force may be less than the opposing user expiration force on the filter body, so the periphery of the chin contact portion may separate from the user&#39;s chin during expiration to benefit user comfort and mitigate eyeglass condensation. The restraining device can be non-elastic. The restraining force of the restraining device can result from its catenary deflection by gravity. The restraining device can be user adjustable. 
    
    
     
       GENERAL DESCRIPTION OF THE DRAWING 
       The drawing shows one embodiment of the respirator worn by a user. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWING 
     Referring to the drawing, a filter mask body  10  is constructed of some material with inherent shape memory that is sufficiently porous to allow air to be drawn through the mask when inhaling, but prevent flow-through of known allergens of predetermined sizes. Mask body  10  incorporates an upper nose contact portion  11  in its vertical plane of symmetry and a lower chin contact portion  12  in its vertical plane of symmetry. A transverse contact plane P that is perpendicular to the vertical plane of symmetry contains both upper nose contact portion  11  and lower chin contact portion  12 . Contact plane P intersects mask body  10  substantially interior to the periphery of mask body  10 . A non-elastic holding strap  20  incorporates a rearward length adjusting means  25 , a left mask connection means  30 , and a right mask connection means  31  not shown. The material of holding strap  20  is sufficiently massive, exceeding approximately 1.5 grams per centimeter in length, to cause a catenary deflection by gravity into a substantially non-straight form when adjusting means  25  is user set to optimize mask body  10  fit and comfort. The positions of left mask connection means  30  and a right mask connection means  31  are approximately coincident with or interior to the intersection of contact plane P and mask body  10 . A distance A not shown extends from upper nose contact portion  11  to the projection of connection means  30  and  31  on plane P and the vertical plane of symmetry. Distance A is less than or equal to approximately one fourth of the distance between upper nose contact portion  11  and lower chin contact portion  12 . 
     In operation, the user places mask body  10  so that upper nose contact portion  11  bears on his or her nose and lower chin contact portion  12  is adjacent to his or her chin. The user adjusts the length of strap  20  so that it drapes in a catenary form between the back of his or her neck or ears and connection means  31  and  32 . The weight of strap  10  in this catenary form provides a low magnitude strap tension on connection points  30  and  31 . When strap  20  is so adjusted the resultant force of mask body  10  on the user&#39;s face is sufficiently low to avoid discomfort and yet positions the mask so that when the user inhales, air flows through the porous mask, and when the user exhales a portion of the air flows around the periphery of lower chin contact portion  12 , as described more fully below. In the above arrangement a chin bearing force between lower chin contact portion  12  and the user&#39;s chin results from a force couple in mask body  10  substantially equal to such strap tension force times distance A. The magnitude of such chin bearing force is user adjustable to be less than user expiration force on the pores of mask body  10 . Provided the inherent shape memory of mask body  10 , when so adjusted the entire mask body  10  then pivots during expiration in its vertical plane of symmetry about upper nose contact portion  11 , so lower chin contact portion  12  separates from the user&#39;s chin. This separation allows user breath to escape around the periphery of lower chin contact portion  12 , which mitigates eyeglass fogging. During inspiration the above lower chin bearing force combines with resistance of air passage though the pores of mask body  10  to seal lower chin contact portion  12  against the user&#39;s chin. 
     Because certain changes can be made to the above described apparatus and methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.