Patent Publication Number: US-2022219025-A1

Title: Flexible Filter Element Having An End Outlet

Description:
TECHNICAL FIELD 
     The present description relates to a filter element of a respiratory protection device, and in particular, a flexible filter element including an outlet near an end of the filter element. 
     CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage filing under 35 U.S.C. 371 of PCT/US2016/018373, filed Feb. 18, 2016, which claims the benefit of U.S. Provisional Application No. 62/121,966, filed Feb. 27, 2015, the disclosure of which is incorporated by reference in its/their entirety herein. 
     BACKGROUND 
     Respiratory protection devices commonly include a mask body and one or more filter elements attached to the mask body. The mask body is worn on a person&#39;s face, over the nose and mouth, and may include portions that cover the head, neck, or other body parts in some cases. Clean air is made available to a wearer after passing through filter media of the filter element. In negative pressure respiratory protection devices, air is drawn through a filter element by a negative pressure generated by a wearer during inhalation. Air from the external environment passes through the filter medium and enters an interior space of the mask body where it may be inhaled by the wearer. 
     Various techniques have been used to construct and attach filter elements to a respirator. Filter elements are commonly connected to an inlet port of a mask body via a threaded engagement, bayonet engagement, or other engagement, for example. In the case of dual filter element respiratory protection devices, in which two filter elements are provided to filter air for a wearer, the filter elements are often connected to air inlets located proximate each cheek portion of the mask, away from a central portion of the mask, such that the filter elements extend outward at sides of the wearer&#39;s head. 
     SUMMARY 
     The present description provides a filter element including filter media having front and rear walls each having a proximal end and a distal end, a side portion at the proximal ends of the front and rear walls, and an outlet, and a breather tube attached to the filter media in fluid communication with the outlet. The outlet is positioned at least partially on the side portion, and the front and rear walls of the filter media are joined together at least partially along a perimeter. 
     The present description further provides a filter element including filter media having front and rear walls each having a proximal end and a distal end, a side portion at the proximal ends of the front and rear walls, and an outlet, and a breather tube attached to the filter media in fluid communication with the outlet. The filter media comprises a single folded filter media portion that forms the front wall and the rear wall, and the front and rear walls are joined at least partially along a perimeter. 
     The present description further provides a filter element including filter media having front and rear walls each having a proximal end, a distal end and a perimeter, a side portion at the proximal ends of the front and rear walls, and an outlet positioned at least partially on the side portion. The filter element further includes a plenum between the front and rear walls of the filter media, and a breather tube adhesively joined to the filter media in fluid communication with the outlet. The filter media includes a single folded filter media portion joined at least partially along a perimeter and forming the front wall and the rear wall and wherein the filter media is sealed around the outlet. 
     The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures and the Detailed Description, which follow, more particularly exemplify illustrative embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present description will be further explained with reference to the appended Figures, wherein like structure is referred to by like numerals throughout the several views, and wherein: 
         FIG. 1  is a perspective view of an exemplary respiratory protection device including a filter element according to the present description. 
         FIG. 2  is a perspective view of an exemplary filter element according to the present description. 
         FIG. 3  is a cross-sectional view of an exemplary filter element according to the present description. 
         FIG. 4  is a perspective view of exemplary filter media cut for assembly according to the present description. 
         FIG. 5  is an exploded perspective view of an exemplary filter element according to the present description. 
     
    
    
     While the above-identified figures set forth various embodiments of the disclosed subject matter, other embodiments are also contemplated. In all cases, this description presents the disclosed subject matter by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this description. 
     DETAILED DESCRIPTION 
     The present description provides a filter element that may be used with a respiratory protection device to provide breathable air for a user. The filter element includes filter media having front and rear walls and a breather tube attached to the filter media at an end or side portion of the filter media. A filter element as described herein may be easily secured to a respiratory protection device in an ergonomic position. 
       FIG. 1  shows an example of a respiratory protection device  10  and filter element  100 . Respiratory protection device  10  may be positioned at least partially over a user&#39;s nose and/or mouth to provide breathable air to a wearer. Respiratory protection device  10  includes a mask body  12  including first and second inlet ports  13  and  14 . First and second (not shown) filter elements  100  may be positioned on opposing sides of mask body  12  and filter air received from the external environment before the air passes into an internal volume within the mask body for delivery to a wearer. 
     Mask body  12  may include a relatively more rigid or semi-rigid portion  12   a  and a compliant face contacting portion  12   b . Compliant face contacting portion  12   b  is compliantly fashioned for allowing the mask body to be comfortably supported over a person&#39;s nose and mouth and/or for providing an adequate seal with the face of a wearer to limit undesirable ingress of air into an interior of mask body  12 , for example. Face contacting member  12   b  may have an interned cuff so that the mask can fit comfortably and snugly over the wearer&#39;s nose and against the wearer&#39;s cheeks. Rigid or semi-rigid portion  12   a  provides structural integrity to mask body  12  so that it can properly support breathing air source components, such as filter elements  100 , for example. In various exemplary embodiments, mask body portions  12   a  and  12   b  may be provided integrally or as separately formed portions that are subsequently joined together in permanent or removable fashion. 
     An exhalation port  15  allows air to be purged from an interior space within the mask body during exhalation by a wearer. In an exemplary embodiment, exhalation port  15  is located centrally on mask body  12 . An exhalation valve is fitted at the exhalation port to allow air to exit due to positive pressure created within mask body  12  upon exhalation, but prevent ingress of external air. 
     A harness or other support (not shown) may be provided to support the mask in position about the nose and mouth of a wearer. In an exemplary embodiment, a harness is provided that includes one or more straps that pass behind a wearer&#39;s head. In some embodiments, straps may be attached to a crown member supported on a wearer&#39;s head, a suspension for a hard hat, or another head covering. 
     First and second inlet ports  13 ,  14  are configured to receive first and second breathing air source components, such as filter elements  100 . In an exemplary embodiment shown in  FIG. 1 , mask body  12  includes first and second inlet ports  13 ,  14  on either side of mask body  12 , proximate cheek portions of mask body  12  for example. First and second inlet ports  13 ,  14  include complementary mating features (not shown) such that filter elements  100  may be securely attached to mask body  12 . Other suitable connections may be provided as known in the art, and in some exemplary embodiments mask body  12  may include only a single inlet port or may include more than two inlet ports, for example. The mating features may result in a removable connection such that filter elements  100  may be removed and replaced at the end of service life of the filter element, or if use of a different breathing air source component is desired. Alternatively, the connection may be permanent such that breathing air source components cannot be removed without damage to the breathing air source component, for example. 
     In various embodiments, filter element  100  may be used with respiratory protection devices that may include a half face mask, full face mask, single inlets and/or multiple inlets. Similarly, filter element  100  may be used with powered-air respiratory protection devices, or other suitable devices. 
       FIGS. 1 through 3  show an exemplary filter element  100  including filter media  110  having a front wall  111 , a rear wall  112 , and an outlet  115  ( FIG. 3 ), and a breather tube  120  attached to filter media  110 . Filter element  100  includes first and second ends  101 ,  102 , and breather tube  120  is positioned proximate first end  101 . In an exemplary embodiment, front and rear walls  111 ,  112  of filter media  110  include proximal ends  111   a ,  112   a , and distal ends  111   b ,  112   b . Filter media  110  includes a side-portion  114  at proximal ends  111   b ,  112   b . In various exemplary embodiments, side portion  114  may include a side wall that extends substantially transverse to front and rear walls  111 ,  112 , and/or may be an interface where front and rear walls  111 ,  112  meet. 
     Front and rear walls  111 ,  112  are fluid permeable and function as fluid inlets, such that air may enter an internal volume  117  of filter element  100  after passing through filter media  110 . Air may then flow to an outlet  115  ( FIG. 3 ), and exit through breather tube  120  to be delivered to a user. 
     Front and rear walls  111 ,  112  include a perimeter  116 . Filter media of the front and rear walls  111 ,  112 , are joined along at least a portion of perimeter  116  such that leakage of air cannot occur between front and rear walls  111 ,  112 . Front and rear walls  111 ,  112  may be joined along at least a portion of perimeter  116 , and in some exemplary embodiments along an entire perimeter  116 , by a thermomechanical bond, such as ultrasonic welding, sewing, adhesive bonding, other suitable methods known in the art or combinations thereof, such that air leakage between front and rear walls  111 ,  112 , is prevented. In an exemplary embodiment, front wall  111  and rear wall  112  are joined together directly around at least a portion of perimeter  116 . In other exemplary embodiments, front wall  111  and rear wall  112  may be joined together indirectly via one or more additional layers, such as a portion of a plenum  130  ( FIG. 3 ), or other suitable layer(s) that allow a secure attachment and prevent leakage. In an exemplary embodiment, a folded, single filter media portion forms front and rear walls  111 ,  112 . Front and rear walls  111 ,  112  may be joined along a portion of perimeter  116 , and side portion  114  includes the location of a fold of filter media  110 , as described in further detail herein. In other exemplary embodiments, front and rear walls  111 ,  112  may be formed from first and second filter media portions that are subsequently joined together. 
     Outlet  115  allows fluid communication between internal volume  117  of filter element  100  and breather tube  120 . In an exemplary embodiment, outlet  115  includes an opening through filter media  110 . In other exemplary embodiments, outlet  115  may be a location of filter media  110  in fluid communication with breather tube  120 , and/or may include fewer or different layers of material than front and rear walls  111 ,  112 , for example. In the exemplary embodiment shown in  FIG. 3 , outlet  115  includes an opening at least partially through side portion  114  of filter media  110 . That is, outlet  115  is positioned near proximal ends  111   a ,  112   a  of front and rear walls  111 ,  112 , and may allow air flow from internal volume  117  through outlet  115  to breather tube  120  in a direction generally parallel to rear wall  112 . In some exemplary embodiments, outlet  115  includes an opening that is at least partially through front wall  111 , rear wall  112 , and/or side portion  114 . An outlet positioned near a proximal end of front and rear walls  111 ,  112 , and at first end  101  of filter element  100 , provides unique ergonomic, usability, and manufacturability features and advantages, as described further herein. 
     In various exemplary embodiments, filter element  100  includes a plenum  130  positioned between or contained within front and rear walls  111 ,  112 . Plenum  130  facilitates more even air flow through front and rear walls  111 ,  112 , and provides additional structure that resists compression and assists in maintaining an internal volume  117  between front and rear walls  111 ,  112 . 
     Plenum  130  may be provided by any suitable component that is resistant to compression when a force is applied and/or acts to return filter element  100  to an original shape after it has been compressed, folded, or otherwise acted on by an external force. In an exemplary embodiment, a nonwoven web of filaments can provide a suitable plenum. One such exemplary plenum is described in U.S. Patent Publication Number 2007/0144123, titled Filter Element that has Plenum Containing Bonded Continuous Filaments. Alternatively, or in addition, other suitable plenums  130  may include a series of ribs, an internal frame, or other suitable features or components to provide additional structure and/or resist compression of filter element  100 . 
     Breather tube  120  may have any suitable shape and configuration such that filtered air may be delivered from filter element  100  to mask body  12 . In an exemplary embodiment, breather tube  120  includes one or more attachment flanges  121 , a nozzle  122  and a cantilever latch  123 . One or more attachment flanges  121  are attached to filter media  110  around a perimeter of outlet  115 , and may include any suitable shape that provides a surface for attachment with filter media  110 . In an exemplary embodiment, attachment flange  121  includes front and rear flange portions  121   a ,  121   b  joined to front and rear walls  111 ,  112  of filter media  110 . 
     In an exemplary embodiment, breather tube  120  may provide a curved recess formed at least in part by attachment flanges  121  that side portion  114  of filter media  110  may reside in. The curved recess may be shaped and sized to accommodate side portion  114  formed by folding filter media  110 , as described further herein. A curved attachment end of breather tube  120  minimizes buckling and creasing, for example, which could otherwise occur when filter media  110  is joined to breather tube  120 . 
     Breather tube  120  may be attached to filter media  110  in any suitable matter that prevents leakage of air into or out of filter element  100 . That is, air cannot enter the internal volume  117  without passing through filter media  110 , when attached to a mask body  12  properly fitted to a user&#39;s face. In various exemplary embodiments, breather tube  120  may be joined to filter media  110  by an ultrasonic weld, adhesive, other suitable techniques, or combinations thereof. In an exemplary embodiment, attachment flanges  121  of breather tube  120  are adhesively joined to filter media  110 , for example front wall  111 , rear wall  112 , and/or side portion  114 . To facilitate bonding, and to prevent leakage, breather tube  120  may be adhesively bonded to filter media  110  at least partially at locations where individual layers of filter media  110  are joined, for example by adhesive or ultrasonic welding such that the layers of filter media  110  are bound together to prevent air from entering internal volume  117  without passing through filter media  110 . In an exemplary embodiment, attachment flanges  121  of breather tube  120  are joined to outer surfaces of filter media  110 . In other exemplary embodiments, one or more attachment flanges  121  may be joined to an inner surface of filter media  110  such that filter media  110  partially covers breather tube  120 . 
     In an exemplary embodiment, attachment flanges  121  provide relatively rigid, external surfaces on opposing sides of filter element  100  that may be gripped by a user when handling filter element  100 , such as when attaching or releasing filter element  100  from mask body  12 . 
     Breather tube  120  includes a nozzle  122  extending generally away from filter media  110 . Nozzle  122  provides a passage for air to flow from internal volume into mask body  12 , and may engage a complementary shaped receiver of mask body  12 , for example. In an exemplary embodiment, nozzle  122  has a non-circular shape that prevents rotation when engaged with a receiver of mask body  12 , and may extend a relatively large lateral distance into a receiver of mask body  12  to allow a secure attachment. Nozzle  122  may extend outwardly generally linearly, or may curve or otherwise exhibit a non-linear shape. Exemplary breather tube  120  shown in  FIGS. 1 through 3  includes a cantilever latch  123  that interacts with features of a receiver of mask body  12  to secure filter element  100  to a mask body  12 . In an exemplary embodiment, cantilever latch  123  extends substantially parallel with nozzle  122 . Upon insertion, opening  124  of cantilever snaps to or mates with receiver  18  to securely attach filter element  100  to mask body  12 . Filter element may be removed by actuating release  17 , for example, and removing filter element  100  away from receiver  18 . In an exemplary embodiment, breather tube  120  thus provides a sleeve-fit engagement between filter element  100  and mask body  12 . One such exemplary engagement is described in U.S. Pat. Pub. No. 2014/0216475, titled Sleeve-Fit Respirator Cartridge. 
     Breather tube  120  may be formed of a suitable material to allow a secure connection with mask body  12 , for example, that is relatively more rigid than filter media  110 , and that is non-porous to prevent inadvertent leakage. In an exemplary embodiment, breather tube may be formed of a polypropylene. Other suitable materials include suitable polymers, other suitable materials, and combinations thereof, and may be selected to provide desired characteristics for a particular application or to appropriately interact with corresponding features of a mask body or other component of a respiratory protection device. In an exemplary embodiment, breather tube  120  is a single, integrally formed component. In other exemplary embodiments, individual portions of breather tube  120 , for example, may be formed separately and subsequently joined or separately attached to filter media  110  to provide desired functionality. In some exemplary embodiments, breather tube  120  and plenum  130  may be integrally formed or joined together. 
     Filter media  110  may be made of any suitable material to provide desired filtration performance. In an exemplary embodiment, filter media  110  includes a polypropylene blown microfiber web. In various exemplary embodiments, filter material may include a nonwoven web, fibrillated film web, air-laid web, sorbent-particle-loaded fibrous web, glass filter paper, other suitable materials known in the art, and combinations thereof. Filter media  110  may include polyolefins, polycarbonate, polyesters, polyurethanes, glass, cellulose, carbon, alumina, other suitable materials known in the art, and combinations thereof. Filter media  110  may also include charged fibers configured to enhance filtration performance, active particulate, such as activated carbon or alumina, catalysts, or other reactive particulate. 
     In some exemplary embodiments, front and rear walls  111 ,  112  of filter media  110  may include or be encompassed by a cover web made from any suitable woven or nonwoven material, such as spunbonded web, thermally bonded webs, or resin-bonded webs. A cover layer may be configured to protect and contain other layers of filter media  110  and may serve as an upstream prefilter layer. 
     In an exemplary embodiment, filter media  110  is made of a non-rigid or flexible material. Accordingly, front and rear walls  111 ,  112  are generally non-rigid and flexible, such that front and rear walls  111 ,  112  may flex or bend when contacted. In an exemplary embodiment, a perimeter  116  of front and rear walls  111 ,  112  may be slightly more stiff or rigid as compared to other portions of front and rear walls  111 ,  112 , but remain non-rigid and flexible such that filter media  110  may bend and flex. 
     Filter media  110  may be cut to any suitable shape to provide a filter element  100  having a desired shape, including triangular, rectangular, trapezoidal, oval, elliptical, or other suitable shape. In an exemplary embodiment, filter element  100  is configured for ergonomic positioning on a mask body. Filter element  100  may be secured to mask body  12 , or other respiratory protection component, such that filter element  100  remains close to a user&#39;s head without substantially interfering with a user&#39;s field of vision, and allowing simultaneous use of other suitable personal protective equipment. In various exemplary embodiments, filter element  100  may be characterized by a first angle ( 0 ). First angle ( 0 ) is an angle formed between a first longitudinal axis A passing through a middle of filter media  110 , and a second longitudinal axis B passing through a middle of nozzle  123  of breather tube  120 . In various exemplary embodiments, first angle ( 0 ) is between about 180° and 120°, 165° and 135°, or about 150°. Such angles facilitate connection with mask body  12  by a user, and ergonomic positioning of filter element  100  when connected to mask body  12 . 
       FIGS. 4 and 5  illustrate an exemplary method of making a filter element as described herein. One exemplary method of making a filter element according to the present description includes steps of cutting filter media to a desired shape and size, folding the filter media, joining the perimeter of the folded filter media, and attaching a breather tube at an end of the filter media. 
     Bulk filter media may be cut using any suitable technique known in the art to provide a filter media portion  210  having a desired shape and size. In an exemplary embodiment, bulk filter media is cut into filter media portions  210  including outlet  215  and outer perimeter  216 . Outlet  215  comprises an opening  215   a  and a sealed region  215   b  where filter media portion  210  is sealed around opening  215   a . That is, in an exemplary embodiment, filter media portion  210  includes multiple layers of material. The multiple layers of material are sealed to prevent leakage of air into an internal volume of the filter element without passing through filter media portion  210  as desired. Sealed region  215   b  may be formed using ultrasonic welding, adhesive, other suitable techniques known in the art, or combinations thereof. 
     Outer perimeter  216  may be shaped to allow filter media portion  210  to be folded proximate the outlet to provide front and rear walls  211 ,  212  and an outlet  215  positioned proximate a side portion  214  formed by the fold of filter media portion  210 . In an exemplary embodiment, a plenum is provided within the filter media portion, and can be positioned before or after filter media portion  210  is folded and/or joined at a perimeter. 
     Folded filter media portion  210  may be joined along at least a portion of perimeter  216  to securely attach, directly or indirectly, front and rear walls  211 ,  212 , and to define an internal volume  217  between front and rear walls  211 ,  212 , as shown in  FIG. 5 . In an exemplary embodiment, at least a portion of perimeter  216  of folded filter media portion  210  is joined by discontinuous ultrasonic welding. Other suitable techniques may be used, including other thermomechanical techniques, such as continuous ultrasonic welding, sewing, adhesive bonding, other suitable techniques known in the art, or combinations thereof, such that air leakage between front and rear walls  211 ,  212 , is prevented. 
     Breather tube  220  is joined to filter media  210  to allow fluid communication with outlet  215 . In an exemplary embodiment, engagement flanges  221   a ,  221   b  of breather tube  220  are adhesively joined to filter media  210 , for example front wall  211 , rear wall  212 , and side portion  114 . To facilitate bonding, and to prevent leakage, breather tube  220  is adhesively bonded to filter media  210  at least partially at sealed region  215   b.    
     A filter element as described herein may be manufactured in any suitable sequence of steps. In an exemplary embodiment, bulk media is prepared by forming a series of outlets  215 , including sealed region  215   b , folded, and joined with a breather tube, such as breather tube  220 . A plenum may then be positioned between front and rear walls  211 ,  212 , before joining front and rear walls  211 ,  212 , and subsequently cutting from the bulk filter media to provide a finished filter element. In various other exemplary methods, the above steps may be provided in other sequences or combinations to provide a filter element as described herein. 
     A filter element as described herein provides several unique features and advantages. Positioning of a breather tube at an end or side portion facilitates easy and secure attachment of the filter element to a mask body or respirator protection device. The filter element may be inserted and snapped into place, for example in a linear direction, without additional rotation or positioning that may be associated with threaded or helical connections. This may be achieved while allowing filter element to reside close to a user&#39;s head and minimizing interference with other personal protective equipment when secured to a mask body. Positioning of breather tube at an end or side portion provides additional advantages in maximizing an effective filtering surface area of front and rear walls because the breather tube does not use substantial space on these surfaces of the filter element. 
     A filter element as described herein provides further manufacturing advantages by allowing a single filter media portion to form front and rear walls of the filter element, in various exemplary embodiments. A breather tube as described herein may also be readily joined to filter media to provide a secure connection, allow easy handling by a user, and may be configured for ergonomic connection with a desired mask body. 
     The present invention has now been described with reference to several embodiments thereof. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Thus, the scope of the present invention should not be limited to the exact details and structures described herein, but rather by the structures described by the language of the claims, and the equivalents of those structures. Any patent literature cited herein is hereby incorporated herein by reference in its entirety to the extent that it does not conflict with the description presented herein. 
     Any feature or characteristic described with respect to any of the above embodiments can be incorporated individually or in combination with any other feature or characteristic, and are presented in the above order and combinations for clarity only. That is, the present disclosure contemplates all possible combinations, sequences, and arrangements of various features of each of the exemplary embodiments and components described herein, and each component may be combined or used in conjunction with any other component as may be desired for a particular application.