Patent Publication Number: US-11020619-B2

Title: Multiple chamber respirator sealing devices and methods

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage filing under 35 U.S.C. 371 of PCT/US2017/022451, filed Mar. 15, 2017, which claims the benefit of U.S. Provisional Application No. 62/313,949, filed Mar. 28, 2016, the disclosure of which is incorporated by reference in its/their entirety herein. 
    
    
     TECHNICAL FIELD 
     This disclosure describes respiratory protection devices and methods including fit check devices, and in some embodiments, respiratory protection devices including multiple air chambers. 
     BACKGROUND 
     Respirator protection devices that cover a user&#39;s nose and mouth, for example, and provide breathable air to a wearer are well known. Air is drawn through a breathable air source by a wearer or forced by a fan or blower into a breathing zone where the air may be inhaled by the wearer. 
     In order to effectively deliver breathable air to a wearer, respiratory protection devices prevent unfiltered air from entering the mask. Various techniques have been proposed for testing the integrity of a face seal, for example, of a respiratory protection device. In a positive pressure test, an exhalation valve of the respiratory protection device is blocked while the wearer exhales into the mask. An adequate seal may be signaled by an increased internal pressure due to an inability of air to exit the mask if a leak is not present. Alternatively, negative pressure tests have been proposed in which a filter cartridge port is blocked while a wearer inhales while wearing the mask. An adequate seal may be signaled by a reduced internal pressure due to the inability of air to enter the mask if a leak is not present. Various mechanisms have been provided for blocking one or more ports to facilitate a negative or positive pressure test. 
     SUMMARY 
     Particular embodiments described herein provide a respiratory protection device including a mask body defining a first chamber, a second chamber, and a breathable air zone for a wearer. First and second breathing air source components are configured for attachment to the mask body such that the first chamber is in fluid communication with the first breathing air source component and the second chamber is in fluid communication with the second breathing air source component. A valve assembly comprising a single actuator is operable between an open configuration and a closed configuration in which fluid communication between the first and second breathing air source components and the breathable air zone is prevented. The first and second chambers are substantially fluidically isolated such that the first chamber is in fluid communication with the breathable air zone through a first inhalation port and the second chamber is in fluid communication with the breathable air zone through a second inhalation port. 
     Embodiments can include any, all, or none of the following features. The first and second inhalation ports may include a check valve configured to allow air to enter the breathable air zone and to prevent exit of air from the breathable air zone into the first or second chambers. A single diaphragm may selectively cover both the first inhalation port and the second inhalation port that is configured to allow air to enter the breathable air zone from the first and second chambers and prevent exit of air from the breathable air zone to the first or second chambers. The mask body may include a central plane that divides the mask body into left and right halves, and the first and second chambers may be separated by a wall oriented at least partially parallel to the central plane. At least portions of the valve assembly may travel within the first and second air chambers when the valve assembly is operated between the open and closed configurations. The valve assembly may include a unitary plunger, with portions of the unitary plunger traveling on each side of a separation wall between the first and second air chambers when the valve assembly is operated between the open and closed configurations. The unitary plunger may move linearly along a longitudinal axis extending along a central plane that divides the mask body into left and right halves. The respiratory protection device may include first and second elastomeric seals. The first breathing air source component may be in sealing engagement with the first elastomeric seal when attached to the mask body and the second breathing air source component may be in sealing engagement with the second elastomeric seal when attached to the mask body. The valve assembly may include first and second sealing surfaces and the first and second inhalation ports may include corresponding sealing surfaces, and in the closed configuration the first sealing surface of the valve assembly contacts the sealing surface of the first inhalation port and the second sealing surface of the valve assembly contacts the sealing surface of the second inhalation port. The actuator may be a button that is depressed when the valve assembly is in the closed configuration. The valve assembly may be biased towards the open configuration. The valve assembly may include first and second sealing surfaces configured to prevent air flow through the first and second air chambers. The first and second sealing surfaces may be configured to move linearly between the open and closed configurations. 
     Particular embodiments described herein provide a method of operating a respiratory protection device including operating a valve assembly from an open configuration, in which a mask body provides a first flow path through a first chamber between a first breathing air source component and a breathable air zone and a second flow path through a second chamber between a second breathing air source component and the breathable air zone, to a closed configuration in which fluid communication through the first and second flow paths is prevented. The first chamber is not in fluid communication with the second chamber, and the valve assembly comprises a single actuator movable from the open configuration to the closed configuration. 
     Embodiments can include any, all, or none of the following features. The method may further include inhaling while the valve assembly is in the closed configuration. The method may further including assessing a fit of the mask body based on an indication observed while inhaling. The indication may be increased difficulty inhaling. The mask body may include a compliant face contacting portion, and the indication may be an inward deflection of the compliant face contacting portion. The method may further include releasing the actuator to allow the valve assembly to return to the open configuration. 
     Particular embodiments described herein provide a respiratory protection device including a mask body defining a first chamber, a second chamber, and a breathable air zone for a wearer. First and second breathing air source components are configured for attachment to the mask body such that the first chamber is in fluid communication with the first breathing air source component and the second chamber is in fluid communication with the second breathing air source component. A valve assembly includes a single actuator operable between an open configuration and a closed configuration in which fluid communication between the first breathing air source component and the breathable air zone is prevented. The first and second chambers are substantially fluidically isolated such that the first chamber is in fluid communication with the breathable air zone through a first inhalation port and the second chamber is in fluid communication with the breathable air zone through a second inhalation port. 
     Embodiments can include any, all, or none of the following features. Fluid communication between the second breathing air source component and the breathable air zone may be prevented in the closed configuration. The first and second inhalation ports may include a check valve configured to allow air to enter the breathable air zone and to prevent exit of air from the breathable air zone into the first or second chambers. A single diaphragm may selectively cover both the first inhalation port and the second inhalation port and may be configured to allow air to enter the breathable air zone from the first and second chambers and prevent exit of air from the breathable air zone to the first or second chambers. At least portions of the valve assembly may travel within the first and second air chambers when the valve assembly is operated between the open and closed configurations. The valve assembly may include a unitary plunger, and portions of the unitary plunger may travel on each side of a separation wall between the first and second air chambers when the valve assembly is operated between the open and closed configurations. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. The above summary is not intended to describe each disclosed embodiment or every embodiment. Other features and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The present description is further provided with reference to the appended Figures, wherein like structure is referred to be like numerals throughout the several views, and wherein: 
         FIG. 1  is a perspective view of an exemplary respiratory protection device. 
         FIG. 2  is a partial cross-sectional view of an exemplary respiratory protection device. 
         FIG. 3  is a partial exploded view of the respiratory protection device of  FIG. 2 . 
         FIG. 4  is a partial cross-sectional view of the respiratory protection device of  FIG. 2  including first and second breathing air source components. 
         FIG. 5  is a partial cross-sectional view of the respiratory protection device of  FIG. 2  showing a valve assembly in a closed configuration. 
     
    
    
     While the above-identified figures set forth various embodiments of the disclosed subject matter, other embodiments are also contemplated. In all cases, this disclosure presents the disclosed subject matter by way of representation and not limitation. 
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The present disclosure provides a respiratory protection device including a mask body defining a breathable air zone for a wearer configured to receive one or more breathing air source components. The respiratory protection device includes a valve assembly selectively operable between an open position in which breathable air may pass from the breathing air source components into the breathable air zone, and a closed position in which airflow is blocked. In some exemplary embodiments, the respiratory protection device includes a first chamber and a second chamber in fluid communication with the breathable air zone and that are substantially fluidically isolated from one another. Breathable air may be delivered to the breathable air zone independently through each of the first and second air chambers without substantial mixing of air received from the first and second breathing air source components before entering the breathable air zone. 
     Referring to  FIG. 1 , an exemplary respiratory protection device  100  is shown that covers the mouth and/or nose of a wearer. Respiratory protection device  100  includes a mask body  110  having one or more receivers  120 . One or more breathing air source components  150  may be attached to mask body  110  at the one or more receivers  120 . First and second breathing air source components  150  may include filter cartridges that filter air received from the external environment before the air enters a breathable air zone of the mask body. In other exemplary embodiments, first and second breathing air source components  150  may include a supplied air component, such as a tube or conduit, powered air purifying respirator component, or other appropriate breathing air source component  150 . 
     Mask body  110  may include a rigid or semi-rigid portion  110   a  and a compliant face contacting portion  110   b . Compliant face contacting portion  110   b  includes a flexible material allowing mask body  110  to be comfortably supported over a person&#39;s nose and mouth and/or provide an adequate seal with the face of a wearer. Face contacting member  110   b  may have an inturned cuff to facilitate a comfortable and snug fit over the wearer&#39;s nose and against the wearer&#39;s cheeks. Rigid or semi-rigid portion  110   a  may provide structural integrity to mask body  110 . In various exemplary embodiments, mask body portions  110   a ,  110   b  may be provided integrally or as one or more separately formed portions that are subsequently joined together in permanent or removable fashion. 
     Mask body  110  includes an exhalation port  111  that allows air to be purged from an interior space within mask body  110  during exhalation by the wearer. In an exemplary embodiment, exhalation valve is located centrally on mask body  110 . An exhalation valve, including a diaphragm or check valve, for example, selectively allows air to exit due to positive pressure within mask body  110 , while preventing ingress of external air. In some exemplary embodiments, exhalation port  111  is positioned at a relatively lower portion of the mask body, for example below the mouth of a wearer. 
     A harness or other support assembly (not shown in  FIG. 1 ) may be provided to support mask body  110  in position over the mouth and/or nose of a wearer. In an exemplary embodiment, a harness includes one or more straps that pass behind a wearer&#39;s head and/or may be attached to a crown member or a headwear suspension supported on a wearer&#39;s head, for example. 
     One or more breathing air source components  150 , such as filter cartridges, may be attached to mask body  110  at first and second receivers  120 . In an exemplary embodiment, first and second receivers  120  are positioned on opposite sides of mask body  110 , proximate check portions of mask body  110 , for example. First and second receivers  120  include complementary mating features such that filter cartridges may be securely attached to mask body  110 . The mating features may provide a removable connection such that the first and second filter cartridges may be removed and replaced at the end of their service life or if use of a different breathing air source component is desired. Alternatively, the connection may be permanent so that the filter cartridge cannot be removed without damage to the filter cartridge. 
     A breathing air source component  150  may be secured to receiver  120  by one or more latches, threads, connectors, or complementary features, for example. In an exemplary embodiment, respiratory protection device  100  includes a cantilever latch  130  that secures breathing air source component  150  to receiver  120  of mask body  110 . Cantilever latch  130  may be integral with breathing air source component  150 , and substantially parallel and/or at least partially co-extending with a nozzle element  155 . Receiver  120  and/or mask body  110  may include one or more complementary mating features that cooperate with cantilever latch  130  to provide a secure connection between body  110  and breathing air source component  150 . In other exemplary embodiments, receiver  120  and/or mask body  110  may include a cantilever latch  130  that cooperates with a feature of breathing air source component  150 , and cantilever latch  130  and/or a complementary mating feature may deflect to result in secure engagement. 
     Breathing air source component  150 , such as a filter cartridge  105 , may filter ambient air, for example, before the air passes into an interior space of mask body  110 . In an exemplary embodiment, filter cartridge  105  includes a body portion  153  including first and second major surfaces  151 ,  152 , and may include one or more sidewalls  154  extending at least partially between first and second major surfaces  151 ,  152 . One or more of the first and second major surfaces  151 ,  152  and/or sidewall are at least partially fluid permeable to allow air to enter filter cartridge  105 . In some exemplary embodiments, filter cartridge  105  may include primarily filter media without an outer housing or surrounded partially by a housing. 
     Filter cartridge  105  includes an outlet nozzle  155  to allow fluid to exit filter cartridge  105  into mask body  110 . In an exemplary embodiment, outlet nozzle  155  extends outwardly from body portion  153 , such as sidewall  154 , and includes a leading end  156 , an outer surface  157  and an inner surface defining an airflow channel through outlet nozzle  155 . In various exemplary embodiments, outlet nozzle  155  may be positioned proximate any of first or second major surfaces  151 ,  152 , one or more sidewalls  154 , or a combination thereof. 
     Filter cartridge  105  is secured to mask body  110  at least in part by engaging with receiver  120 . In an exemplary embodiment, outlet nozzle  155  is inserted into an opening of receiver  120  defined in part by an elastomeric seal (not shown in  FIG. 1 ). A rigid outer portion of receiver  120 , for example, may provide primary structural support and stability between mask body  110  and filter cartridge  105 , and the elastomeric seal may sealingly engage outer surface  157  and/or other portions of outlet nozzle  155  and filter cartridge  150  to prevent ingress of contaminants or debris from an external environment. 
     Respiratory protection device  100  includes a valve assembly  170  having one or more components to selectively prevent airflow from one or more breathing air source components  150  to the breathable air zone of mask body  110 . Valve assembly  170  is operable between a closed configuration in which fluid communication between one or more breathing air source components  150  are blocked, and an open configuration in which breathable air may flow from breathing air source components  150  to the breathable air zone of mask body  110 , as described in greater detail herein. 
     Referring to  FIGS. 2-5 , an exemplary respiratory protection device  200  is shown. Respiratory protection device  200  includes a mask body  210  (portions of which are omitted in  FIGS. 2-5 ) defining a breathable air zone  211 , and in some embodiments may be similar to respiratory protection device  100  described above. Respiratory protection device  200  includes a first air chamber  213 , a second air chamber  214 , and a valve assembly  270  that selectively blocks airflow through the first and second air chambers. A wearer may operate valve assembly  270  to selectively prevent airflow from one or more breathing air source components to the breathable air zone to perform a fit test. 
       FIG. 2  shows a partial cross-sectional view of exemplary respiratory protection device  200  including a first air chamber  213  and second air chamber  214  in selective fluid communication with breathable air zone  211 . Breathable air may enter mask body  210  at first receiver  220   a , flow through first air chamber  213 , and pass through a first inhalation port  215  into breathable air zone  211 . Similarly, breathable air may enter mask body  210  at second receiver  220   b , flow through second air chamber  214 , and pass through a second inhalation port  216  into breathable air zone  211 . 
     In an exemplary embodiment, breathable air from first and second breathing air source components remains substantially unmixed until after entering breathable air zone  211 . Breathable air may flow through first and second air chambers  213 ,  214  and into breathable air zone  211  relatively independently. Independent flow of air from first and second breathing air sources may promote controlled flow through mask body  210  and/or reduce turbulent mixing of air that could be associated with increased pressure drop through the mask body and increased breathing resistance. Substantially independent air flow paths to breathable air zone  211  through first and second air chambers  213 ,  215  may thus reduce pressure drop through the mask body and reduce breathing resistance. 
     Furthermore, first and second air chambers  213 ,  214  that deliver air to breathable air zone  211  substantially independently allow flexibility in the configuration and positioning of receivers  220 , inhalation ports  215 ,  216 , and/or other components of mask body  210 . In an exemplary embodiment, receivers  220  are positioned at substantially opposite sides of mask body such that air flows through first and second air chambers  213 ,  214 , respectively, in substantially opposite, or otherwise different, directions towards first and second inhalation ports. Because air chambers  213 ,  214  are substantially fluidically isolated, interaction between air flowing in different directions from first and second breathing air source components that could result in turbulent air flow and associated resistance is reduced. 
     First and second air chambers  213 ,  214  may be defined by one or more components of mask body  210  and exhibit an appropriate shape to provide air flow between a breathing air source component attached to mask body  210  and breathable air zone  211 . For example, first chamber  213  is defined at least in part by interior wall  217  and an outer wall  218  of mask body  210 . First air chamber  213  is substantially sealed from the external environment, except for air that may enter through a first receiver  220  from a first breathing air source component, and exit through first inhalation port  215  into breathable air zone  211 . Second chamber  214  may similarly be defined at least in part by interior wall  217  and an outer wall  218  of mask body  210 , and may be substantially sealed from the external environment, except for air that may enter through a second receiver  220  from a second breathing air source component, and exit through second inhalation port  216  into breathable air zone  211 . 
     A separation wall  212  may divide first and second air chambers  213 ,  214 . In some exemplary embodiments, separation wall  212  may be a common separation wall such that first and second air chambers  213 ,  214  are positioned directly on opposing sides of separation wall  212 . Separation wall  212  may be centrally located, and for example may be positioned at least partially along and/or parallel to a central plane dividing mask body  210  into left and right halves. Separation wall  212  may extend substantially across an entire distance between interior wall  217  and actuator and/or plunger  271  of valve assembly  270  to substantially fluidically isolate first and second air chambers  213 ,  214 . 
     A mask body having a breathable air zone defined at least in part by interior wall  217  of mask body  210 , and first and second air chambers  213 ,  214  defined at least in part by interior wall  217  of the mask body and/or positioned outwardly from breathable air zone  211 , provides multiple air chambers that may be substantially fluidically isolated while minimizing extra bulk or weight. Further, mask body  210  may be configured to have an outer wall  218  that is close to the wearer&#39;s face and does not result in an unduly large moment of inertia that could be perceived to cause discomfort. 
     Each of first and/or second air chambers  213 ,  214  may provide a duct to direct air from one or more breathing air source components to the first and second inhalation ports  215 ,  216 , respectively. First and second air chambers  213 ,  214  allow receivers  220  and inhalation ports  215 ,  216  to be independently positioned at different locations of mask body  210 . For example, receivers  220  may be positioned near cheek positions and/or rearward of an outermost front portion of mask body  210 , while inhalation ports  215 ,  216  may be positioned proximate a central axis extending centrally through mask body  210 . In some exemplary embodiments, such a configuration allows breathing air source components, such as filter cartridges, to extend rearwardly along a wearer&#39;s face to promote a center of mass close to the wearer, and to reduce the presence of breathing air source components within the wearer&#39;s field of vision. 
     Interior wall  217  may at least partially define first and second air chambers  213 ,  214  and include first and second inhalation ports  215 ,  216  extending through interior wall  217 . First and second inhalation ports  215 ,  216  include an inhalation valve that selectively allows fluid communication into breathable air zone  211  from first and second air chambers  213 ,  214 , respectively. In an exemplary embodiment, the inhalation valve includes a flap or diaphragm  219 . Diaphragm  219  may be secured at a central location, between first and second inhalation ports  215 ,  216 , for example, by one or more pins or flanges, at a peripheral edge, or other appropriate location. Diaphragm  219  is biased towards engagement with interior wall  217 , for example a perimeter of openings defined by first and/or second inhalation ports  215 ,  216 , to selectively allow passage of air into breathable air zone  211 . When pressure in the breathable air zone is greater than first and/or second air chambers  213 ,  214 , such as during exhalation, diaphragm  219  remains urged in sealing engagement with interior wall  217  so that air cannot exit breathable air zone  211  through inhalation ports  215 ,  216 . When pressure in the breathable air zone is less than first and/or second air chambers  213 ,  214 , such as during inhalation, diaphragm  219  may deflect or open to allow air to flow from first and/or second air chambers  213 ,  214  into breathable air zone  211 . In an exemplary embodiment, diaphragm  219  includes a single, integral diaphragm  219  including first and second diaphragm portions  219   a ,  219   b  associated with an opening defined by the first and second inhalation ports  215 ,  216 , respectively. In some exemplary embodiments, diaphragm  219  includes a first diaphragm  219   a  and a second diaphragm  219   b  that is separate and independent from first diaphragm  219   a.    
     Respiratory protection device  200  may include one or more elastomeric seals  260  that promotes a sealed connection between mask body  210  and a breathing air source component. Elastomeric seal  260  may include an O-ring, gasket, sealing sleeve, or other appropriate seal. In an exemplary embodiment, elastomeric seal  260  receives a portion of a breathing air source component, such as a nozzle or outlet, and includes a first end portion  261 , a second end portion  262 , an outer surface  263  and an inner surface  264  at least partially defining a channel  265 . First end portion  261  may be connected to a rigid component of a mask body, such as receiver  220 . In an exemplary embodiment, elastomeric seal  260  provides an elastomeric sleeve that at least partially surrounds an outer surface of a breathing air source component, such as a filter cartridge  250 , attached to mask body  210 , and has a length (L) between first and second ends such that at least a portion of a breathing air source component  250  may be positioned within channel  265 . In some exemplary embodiments, length (L) may be between 5 mm and 100 mm, 10 mm and 40 mm, or about 20 mm. Second end portion  262  and/or various locations of elastomeric seal  260  may be floating or otherwise not anchored to a rigid component of mask body  210  such that elastomeric seal  260  may move or deform at least partially independently of a portion of mask body  210 , while first end portion  261  is anchored and/or rigidly secured with a component of mask body  210  (not shown in  FIG. 2 ). 
     Referring to  FIGS. 2-3 , respiratory protection device  200  includes a valve assembly  270  operable between open and closed configurations including an actuator  271  and a plunger  272  having one or more sealing surfaces, such as sealing surfaces  277 ,  278 . Actuator  271  is operable by a user to move valve assembly  270  between the open and closed configurations. Actuator  271  may be a button, such as an over-molded elastomeric push-button, slidable button, or the like, that may be pressed inward or otherwise operated to move plunger  272 . For example, actuator  271  may be pressed inwardly to cause plunger  272  to move towards first and second inhalation ports  215 ,  216 . In various exemplary embodiments, actuator  271  may alternatively or additionally include a twist mechanism, lever, slider, or other appropriate actuator  271  operable to move valve assembly between open and closed configurations. In some embodiments, valve assembly  270  may be supported at least partially between outer wall  218  and/or a front portion of mask body  210  that engages or is integral with a rear portion of mask body  210 , such as interior wall  217 , that at least partially defines breathable air zone  211 . 
     In an exemplary embodiment, valve assembly  270  includes an actuator  271  that is operable to move valve assembly  270  into a closed configuration in which air flow from two or more breathing air source components is prevented from entering breathable air zone  211  of mask body  210 . For example, operation of actuator  271  may cause sealing surfaces of plunger  272  to sealingly engage complementary sealing surfaces of first and second inhalation ports  215 ,  216 . Plunger  272  may have a first sealing surface  277  configured to sealingly engage a complementary first sealing surface  215   a  of first inhalation port  215 , and a second sealing surface  278  configured to sealingly engage a complementary second sealing surface  216   a  of second inhalation port  216 . In an open configuration, sealing surfaces  277 ,  278  of plunger  272  are spaced from inhalation ports  215 ,  216  and complementary sealing surfaces  215   a ,  216   a . In the closed configuration, first and second sealing surfaces  277 ,  278  of plunger  272  sealingly engage complementary sealing surfaces  215   a ,  216   a , to prevent airflow from first and second chambers  215 ,  216  into breathable air zone  211 . Alternatively or additionally, valve assembly  270  may prevent airflow by sealing engagement with elastomeric seal  260 , receiver  220 , or other component of mask body  210  to prevent airflow from first and/or second breathing air source components to breathable air one  211 . 
     Sealing surfaces  215   a ,  216   a  of first and second inhalation ports  215 ,  216  facilitate consistent sealing engagement with complementary sealing surfaces of valve assembly  270 , such as sealing surfaces  277 ,  278 , without requiring a user to exert excessive force on actuator  271 . In an exemplary embodiment, sealing surfaces  215   a ,  216   a  of first and second inhalation ports  215 ,  216  may include a raised surface, rib, flange, or the like, that surround first and second openings defined by first and second inhalation ports  215 ,  216 , respectively, and promote consistent contact. Sealing surfaces  277 ,  278  of plunger  272  and/or sealing surfaces  215   a ,  216   a  of first and second inhalation ports  215 ,  216  may include a compliant or resilient material to promote consistent sealing. For example, first and second sealing surfaces  215   a ,  216   a  may include an elastomeric gasket or flange extending from interior wall  217 . The gasket or flange may flex or bend when contacted by plunger  272  to promote consistent engagement around an entire perimeter of sealing surfaces  215   a ,  216   a . Alternatively or in addition, sealing surfaces  277 ,  278  of plunger  272  may include a compliant or resilient material such that sealing surfaces  277 ,  278  may flex and/or rotate or articulate with contact against sealing surfaces  215   a ,  216   a . Sealing surfaces including one or more compliant or resilient portions may promote consistent sealing engagement over a range of plunger displacements and orientations that may vary, for example, based on a force on actuator  271  applied by a user or broad dimensional tolerances of valve assembly  270  and other components of respiratory protection device  200 . 
       FIG. 3  shows a partial exploded view of exemplary respiratory protection device  200 . First and second inhalation ports  215 ,  216  are positioned on interior wall  217 . Interior wall  217  may be integral to or assembled with one or more other portions of mask body  210 . For example, interior wall  217  may include one or more seals  241  to provide air tight sealing engagement with outer wall  218  or another portion of mask body  210 . 
     In an exemplary embodiment, valve assembly  270  includes a guide  280  that maintains alignment of sealing surfaces  277 ,  278  between open and closed configurations. Guide  280  may be positioned between actuator  271  and plunger  272 , and interact with complementary features of plunger  272  during movement between open and closed positions. For example, plunger  272  may have one or more tabs  291  defining a width that fits within an opening  281  of guide  280  and maintains plunger  272  and/or sealing surfaces in appropriate alignment. 
     Valve assembly  270  may include a unitary plunger  272  defining sealing surfaces  277 ,  278 , or include one or more components defining sealing surfaces  277 ,  278 . In an exemplary embodiment, plunger  272  is configured to at least partially receive and/or travel over interior wall  212 . For example, plunger  272  includes a channel  279  that separation wall  212  may at least partially reside within when valve assembly  270  moves between open and closed configurations, such that portions of plunger  272  may travel on each side of separation wall  212  when the valve assembly is operated between the open and closed configurations. Valve assembly  270  may thus be configured to close first and second inhalation ports  215 ,  216  located at first and second air chambers  213 ,  214 , that are substantially fluidically isolated from one another, by operating a single actuator  271 . Accordingly, a wearer may readily perform a fit text of respiratory protection device  200  having multiple breathing air source components by operation of a single actuator  271 . 
     Referring to  FIGS. 4 and 5 , partial cross-sectional views are shown of respiratory protection device  200  including first and second breathing air source components attached to first and second receivers  220  with valve assembly  270  in an open configuration ( FIG. 4 ) and a closed configuration ( FIG. 5 ). In the open configuration, air may flow from a first breathing air source component, such as first filter cartridge  250   a , into first air chamber  213 , and through first inhalation port  215  into breathable air zone  211 , and from a second breathing air source component, such as second filter cartridge  250   b , into second air chamber  214 , and through second inhalation port  216  into breathable air zone  211 . In a closed configuration shown in  FIG. 5 , sealing surfaces  277 ,  278  of valve assembly  270  are in sealing engagement with complementary sealing surfaces of first and second inhalation ports  215 ,  216 . Alternatively or in addition, sealing surfaces  277 ,  278  may contact second end portion  262  of first and second elastomeric seals  260 , or another component of mask body  210 , to substantially prevent fluid communication between first and second breathing air source components and breathable air zone  211 . 
     Receiver  220  is configured such that outlet nozzle  255  of filter cartridge  250  may slide into a channel  265  defined by elastomeric seal  260 . Outer surface  257  of outlet nozzle  255  contacts inner surface  264  of elastomeric seal  260  to provide sealing engagement between filter cartridge  250  and receiver  220 . A rigid outer portion  221  of receiver  220  may provide substantial structural support and stability between mask body  210  and filter cartridge  250  while engagement between elastomeric seal  260  and filter cartridge  250  provides an adequate seal to prevent ingress of unwanted contaminants or debris from the external environment. 
     In an exemplary embodiment, outer surface  257  of outlet nozzle  255  may be relatively larger than channel  265  defined by inner surface  264  to promote an interference fit and a snug sealing engagement between outlet nozzle  255  and elastomeric seal  260 . Alternatively or in addition, elastomeric seal  260  may include sections of varying wall thickness and/or having a contoured shape. For example, inner surface  264  may include one or more ribs  267  positioned at a location configured to contact outer surface  257  of outlet nozzle  255 . One or more ribs  267  promote continuous contact around a perimeter of outlet nozzle to provide an adequate seal. Furthermore, one or more ribs  267  may provide an area of concentrated pressure between outlet nozzle  255  and elastomeric seal  260  that may promote robust sealing without requiring excessive force by a user when engaging filter cartridge  250  with receiver  220 . 
     A wearer of respiratory protection device  200  may perform a fit test by positioning mask body  210  in a position of use over a mouth and/or nose and operating valve assembly  270 . For example, with mask body  210  in a position of use, and one or more filter cartridges  250  engaged to mask body  210 , valve assembly  270  may be operated from the open configuration to the closed configuration. Operation of actuator  271 , by pressing actuator  271  inwardly, for example, causes plunger  272  to move from the open position ( FIG. 4 ) to the closed configuration ( FIG. 5 ), while portions of valve assembly  270  are on each side of separation wall  212 . In the closed configuration, sealing surfaces  277 ,  278  of plunger  272  are in sealing engagement with complementary sealing surfaces  215   a ,  216   a  of first and second inhalation ports  215 ,  216 . 
     Operation of valve assembly  270  from the open configuration to the closed configuration allows a user to perform a fit test to confirm a desired seal is formed between mask body  210  and the user&#39;s face, for example, by providing an indicator of the presence and/or absence of a leak that may be observed by the wearer. When valve assembly  270  is in the closed configuration, air is prevented from entering breathable air zone  211  from first and second air chambers  215 ,  216 . Inhalation by a wearer in the closed configuration thus creates a negative pressure within mask body  210 , and may cause increasingly greater difficulty for the user to further inhale. Alternatively or additionally, inhalation in the closed configuration may cause a compliant face contacting portion, such as compliant face contacting portion  110   b  ( FIG. 1 ), to deflect inwardly if a seal is formed with the user&#39;s face. If an adequate seal is not achieved, a negative pressure may not be created and associated indicators of an adequate seal may not be present. Accordingly, operation of valve assembly  270  to the closed configuration, followed by inhalation by the user, provides an indication of whether a seal is formed between respiratory protection device  200  and the user&#39;s face. 
     Actuator  271  and/or plunger  272  may be configured to move linearly along a longitudinal axis between open and closed configurations. For example, actuator  271  and/or plunger  272  may move linearly between open and closed configurations along a longitudinal axis (A) extending centrally through actuator  271  and/or plunger  272 . Longitudinal axis (A) may extend orthogonal to an outer surface of actuator  271 . In some exemplary embodiments, longitudinal axis (A) passes substantially centrally through actuator  271  and plunger  272 , and between first and second inhalation ports  280 . 
     First and/or second sealing surfaces  277 ,  278  may similarly move linearly along an axis of travel between open and closed configurations, and guide  280  may maintain appropriate alignment with first and second inhalation ports  215 ,  216  to result in sealing engagement in the closed configuration. Alternatively or in addition, actuator  271  and/or plunger  272  may travel along a shaft or rail positioned along longitudinal axis (A) or parallel and spaced from longitudinal axis (A). In some embodiments, actuator  271  and/or plunger  272  may “float” or be supported substantially by flexible web  274  of actuator  271 . Flexible web  274  may maintain actuator  271  and/or plunger  272  in substantial alignment with longitudinal axis (A) during movement between open and closed configurations, and maintain sealing surfaces in position for appropriate alignment with first and second inhalation ports  215 ,  216 , and/or other component of mask body  110 , to selectively prevent air flow from first and second air chambers  213 ,  214  to breathable air zone  211 . Alternatively or in addition, actuator  271 , plunger  272  and/or sealing surfaces  277 ,  278  may pivot, rotate, or travel at least partially along a non-linear path between open and closed configurations. 
     Valve assembly  270  may be biased to return to a desired configuration in the absence of an applied force by a user. For example, valve assembly  270  includes one or more resilient members that return valve assembly  270  to an open configuration ( FIG. 4 ) when released by a user. In an exemplary embodiment, actuator  271  is an elastomeric button that acts as a resilient member biasing plunger  272  towards the open configuration in which sealing surfaces  277 ,  278  are out of sealing engagement with complementary sealing surfaces  215   a ,  216   a  of first and second inhalation ports  215 ,  216 . Actuator  271  may include a flexible web  274  attached to an outer wall  218  or other rigid component of mask body  210  to support actuator  271  and bias actuator  271  to the open configuration. Web  274  is formed of a flexible or compliant material that is able to elastically deform when actuator is pressed inwardly by a user, while acting to return valve assembly  270  to the open configuration in the absence of an applied force by the user. Alternatively or additionally, valve assembly  270  may include one or more resilient members. In various exemplary embodiments, a coil spring, leaf spring, or elastomeric band, for example, may be provided to bias valve actuator  271  and/or plunger  272  towards the open position. 
     Actuator  271  and plunger  272  may be connected, directly or indirectly, to facilitate operation between the open and closed configurations. In an exemplary embodiment, plunger  272  has greater rigidity or stiffness compared to actuator  271 . Actuator  271  and plunger  272  may be joined by a snap-fit connector  275  of actuator  271  positioned through an aperture  276  of plunger  272 . Alternatively or in addition, actuator  271  and plunger  272  may be joined by rivets, mechanical fasteners, adhesive, or one or more intermediate components, for example. A substantially rigid plunger  272  may facilitate robust sealing engagement with a substantially flexible or compliant second end portion  262  of elastomeric seal  260 . In some exemplary embodiments, actuator  271  and plunger  272  are joined such that guide  280  is positioned between actuator  271  and plunger  272 . 
     The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood there from. 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 disclosure. 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. Thus, the scope of the present disclosure should not be limited to the exact details and structures described herein. Moreover, although features may be described herein as acting in certain combinations and/or initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.