Patent Publication Number: US-11040226-B2

Title: Serviceable cartridge assembly for respirator exhalation unit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/541,780 entitled “Serviceable Cartridge Assembly for Respirator Exhalation Unit,” filed with the U.S. Patent and Trademark Office on Nov. 14, 2014 and now U.S. Pat. No. 10,279,204 issued May 7, 2019, which application is based upon and claims priority from U.S. Provisional Patent Application Ser. No. 61/904,273 entitled “Serviceable Cartridge Assembly for Respirator Exhalation Unit,” filed with the United States Patent and Trademark Office on Nov. 14, 2013, the entire disclosures of which are incorporated herein by reference in their entireties. 
    
    
     GOVERNMENT LICENSE RIGHTS 
     This invention was made with Government support under contract number W91CRB-11-D-0001 awarded by the U.S. Army. The Government may have certain rights in the invention. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to breathing apparatus for protective masks, and more particularly to exhalation valve assemblies for use on protective masks configured to cooperate with varied personal protective equipment. 
     BACKGROUND 
     Protective masks have long been used to protect the wearer in hazardous environments from inhaling contaminants and potentially harmful materials. They provide a protective, breathable environment to the wearer in contaminated and environmentally threatening conditions, such as fires, chemical spills, radiological events, etc. that might be faced by firefighters, first responders, etc. Protective masks are typically configured with a facemask and valved assemblies for controlling the flow of air to and from the interior of the mask. 
     The entrance of air into the mask interior may be (by way of non-limiting example) through one or more filters, from self-contained breathing apparatus (SCBA), or through powered air purifying respirators (PAPR), or other air supply mechanisms as may be known to those having ordinary skill in the art. 
     More particularly, in one mask configuration, air is drawn into the mask interior through the wearer&#39;s inhalation, creating a negative pressure environment inside the mask (with respect to ambient air pressure), with the air typically being drawn into the mask through one or more air purifying filter canisters. As the user exhales, a positive pressure is created in the interior of the mask, and a check valve typically opens to allow the exhaled air to exit the mask through an outlet. In this configuration, a simplistic negative pressure valve is typically used to prevent contaminated air from entering through the outlet during the wearer&#39;s inhalation. 
     Likewise, in another mask configuration, air is supplied to the mask in a SCBA system from an air supply, such as an air tank, which provides a positive pressure environment inside of the mask. As the wearer inhales, a supply valve opens to allow air into the mask from the tank. As the user exhales, the supply valve closes and the check valve opens to release the exhaled air out from the mask. 
     Still further, in yet another mask configuration, air is supplied to the mask in a PAPR system from a motorized blower that delivers filtered air to the mask, again creating a positive pressure environment insider of the mask. The pressure supplied by the blower is typically lower than pressure supplied through a SCBA system, and is thus sent from the blower (at times through a supply valve), through a hose and into the interior of the mask. Once again, as the wearer exhales, the supply valve closes and the check valve opens to release the exhaled air from the mask. 
     A challenge exists, however, in that the above-described varying mask configurations, each of which is particularly desirable for a particular set of threat conditions, require variously configured exhalation valves. Specifically, the pressure that the exhalation valve must maintain in order to not inadvertently open and allow contaminated air into the mask will vary with the pressure created inside of the mask environment, which in turn will vary with the protective equipment configuration being used (i.e., whether such configuration includes filter canisters mounted to a mask, a PAPR system, a SCBA system, or other systems). Moreover, the pressure that the user must overcome by the check valve to allow their exhaled air to exit must likewise be balanced so as to not excessively stress the wearer. Thus, in the event that a wearer must change their protective equipment due to a changing threat environment, they typically will not only need to change the protective equipment itself, but likewise will need to change the exhalation valve configuration in order to provide an exhalation assembly that is properly fitted to the selected protective equipment. 
     Even further, given the harsh operating conditions in which such protective mask assemblies are used, the exhalation assemblies are quite prone to damage due to prolonged exposure to the threatening environment. Unfortunately, however, in typical exhalation units used with such protective masks, the exhalation valve assemblies are complex and enclosed, requiring that the entire unit be replaced in the event that individual components of the exhalation valve assembly require service or replacement. 
     It would therefore be advantageous to provide an exhalation valve assembly for use with protective masks that is easily adaptable to use with varied personal protective equipment configurations without changing out the exhalation valve structure, that is less complex than previously known exhalation valve assemblies, and that allows easy breakdown so that the wearer may easily service the components of the exhalation valve unit. 
     SUMMARY OF THE INVENTION 
     Disclosed is a serviceable cartridge assembly for a respirator exhalation unit that is modular, simple in construction, and that allows quick-connect of an exhalation valve cartridge in a mask to minimize the need for reconfiguration when changing personal protective equipment, and that allows for easy removal and breakdown for servicing and/or replacement of individual components of the exhalation valve without modifying or replacing other elements of the protective mask. The assembly may be convertible from a negative only pressure valve assembly to a negative/positive pressure valve assembly, and vice versa, and a grill may be provided on an outlet side of the cartridge assembly, the rotation of which converts the assembly from a negative pressure valve to a positive pressure valve. Moreover, the components of the cartridge assembly are modular, such that one grill configured as a rotating grill that converts the valve from a negative only valve system to a negative/positive valve system may be quickly and easily replaced with an alternative, static and fixed grill. Likewise, given such modular construction, the internal components of the cartridge assembly that act between the rotating grill and the valve (in the negative/positive pressure valve system) may be quickly and easily removed. With this configuration, the assembly may be easily modified from a negative/positive field serviceable valve system to a negative only field serviceable valve system, and vice versa, with minimal effort on the part of the operator. 
     In accordance with certain aspects of an embodiment of the invention, a serviceable cartridge assembly for a respirator exhalation unit is provided, comprising: a cylindrical cartridge body having an air inlet side and an air outlet side; a negative pressure valve positioned on an interior of the cylindrical cartridge body and configured to seal the air inlet side upon creation of a pressure below ambient pressure upstream of the air inlet side, the negative pressure valve being frictionally held within the air inlet side of the cylindrical cartridge body; and a grill removably attached to the air outlet side of the cylindrical cartridge body and having a circumferential edge forming a snap fit connection with a circumferential recess on an interior of the cylindrical cartridge body adjacent the outlet side of the cylindrical cartridge body. 
     In accordance with further aspects of an embodiment of the invention, a serviceable cartridge assembly for a respirator exhalation unit is provided, comprising: a cylindrical cartridge body having an air inlet side and an air outlet side; a valve positioned on an interior of the cylindrical cartridge body, the valve being reconfigurable from a negative pressure valve to a positive pressure valve and configured to seal the air inlet side, the valve being frictionally held within the air inlet side of the cylindrical cartridge body; and a grill removably attached to the air outlet side of the cylindrical cartridge body and having a circumferential edge forming a snap fit connection with a circumferential recess on an interior of the cylindrical cartridge body adjacent the outlet side of the cylindrical cartridge body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying drawings in which: 
         FIG. 1  is an exploded view of a removable cartridge assembly in accordance with certain aspects of an embodiment of the invention. 
         FIG. 2  is a front view of the assembled removable cartridge assembly of  FIG. 1 . 
         FIG. 3  is a top view of the assembled removable cartridge assembly of  FIG. 1 . 
         FIG. 4  is a side view of the assembled removable cartridge assembly of  FIG. 1 . 
         FIG. 5  is a front view of the removable cartridge assembly of  FIG. 1  positioned for placement within a protective mask. 
         FIG. 6  is a front view of the removable cartridge assembly of  FIG. 1  mounted within a protective mask. 
         FIG. 7  is a top view of the removable cartridge assembly of  FIG. 1  with a front grill removed. 
         FIG. 8  is a cross-sectional view of the removable cartridge assembly of  FIG. 7  along section line A-A of  FIG. 7 . 
         FIG. 9  is a close-up view of a valve seal for use with the removable cartridge assembly of  FIG. 7 . 
         FIG. 10  is a close-up view of a recess for mounting a grill on the removable cartridge assembly of  FIG. 7 . 
         FIG. 11  is a top view of a grill for use with the removable cartridge assembly of  FIG. 7 . 
         FIG. 12  is a side view of the grill of  FIG. 11 . 
         FIG. 13  is a cross-sectional view of the grill of  FIG. 11  along section line A-A. 
         FIG. 14  is an exploded view of a removable cartridge assembly in accordance with further aspects of an embodiment of the invention. 
         FIG. 15  is a front view of the assembled removable cartridge assembly of  FIG. 14 . 
         FIG. 16  is a top view of the assembled removable cartridge assembly of  FIG. 14 . 
         FIG. 17  is a side view of the assembled removable cartridge assembly of  FIG. 14 . 
         FIG. 18  is a front view of the removable cartridge assembly of  FIG. 14  positioned for placement within a protective mask. 
         FIG. 19  is a front view of the removable cartridge assembly of  FIG. 14  mounted within a protective mask. 
         FIG. 20  is a top view of a grill for use with the removable cartridge assembly of  FIG. 14 . 
         FIG. 21  is a bottom view of the grill of  FIG. 20 . 
         FIG. 22  is a cross-sectional view of the grill of  FIG. 20  along section line A-A. 
         FIG. 23  is a cross-sectional view of the grill of  FIG. 20  along section line B-B. 
         FIG. 24  is a side view of the grill of  FIG. 20 . 
         FIG. 25  is a top view of a load disc for use with the removable cartridge assembly of  FIG. 14 . 
         FIG. 26  is a side view of the load disc of  FIG. 25 . 
         FIG. 27  is a cross-sectional view of the load disc of  FIG. 25  along section line H-H. 
         FIG. 28  is a cross-sectional view of the load disc of  FIG. 25  along section line A-A of  FIG. 26 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following description is of a particular embodiment of the invention, set out to enable one to practice an implementation of the invention, and is not intended to limit the preferred embodiment, but to serve as a particular example thereof. Those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form. 
     Disclosed herein is a removable cartridge assembly for use in a respirator exhalation unit, such as an exhalation unit on a protective mask, such as a gas mask. Such removable cartridge assembly is particularly configured to allow users to easily breakdown the components of the cartridge assembly for service, such as when individual components of the cartridge assembly need to be replaced, or when portions of the assembly need to be cleaned or cleared of debris or contaminants. The removable cartridge assembly described herein may be used in a variety of respirator exhalation units, including by way of non-limiting example a respirator exhalation unit as set forth in U.S. Pat. No. 7,866,319, the specification of which is incorporated herein by reference thereto in its entirety. 
       FIG. 1  shows an exploded view of a removable cartridge assembly (shown generally at  100 ) in accordance with certain aspects of an embodiment of the invention. Likewise,  FIGS. 2, 3 and 4  provide front, top, and side views, respectively, of removable cartridge assembly  100  in a fully assembled state. The removable cartridge assembly shown in  FIGS. 1 through 4  is particularly configured for use in a negative pressure only valve system. In such negative pressure only valve system, air pressure inside of a mask to which an exhalation unit is attached is negative (with respect to ambient pressure) during inhalation, and is positive during exhalation. During inhalation, air enters the mask through, for instance, a filter, such as a CBRN filter, and during exhalation, air exists the mask through the exhalation unit through a check valve. In the embodiment of  FIG. 1 , the removable cartridge assembly  100  includes a cartridge body  110 , a front grill  120  that may be removably attached to a front edge  1101  corresponding to the outlet side of cartridge body  110 , and a negative pressure valve  130  that may be removably attached to cartridge body  110  through a central opening  115  at the inlet side  1102  of cartridge body  110 , each of which components are discussed in greater detail below. 
     Removable cartridge assembly  100  is configured for removable placement within the exhalation unit mount  502  of a protective mask  500 , as shown in  FIG. 5  (showing removable cartridge assembly  100  about to be placed into the exhalation unit mount  502  of a protective mask  500 ) and  6  (showing removable cartridge assembly  100  seated within exhalation unit mount  502  of protective mask  500 ). In order to allow for the quick connect attachment of removable cartridge assembly  100  with exhalation unit mount  502  of a protective mask, flanges  116  are positioned on an outer cylindrical wall  108  of cartridge body  110 , which flanges  116  align with openings  504  in exhalation unit mount  502  of mask  500  that initially receive flanges  116 , and are positioned adjacent a ridge or shelf (not shown) that hold flanges  116  in place as cartridge body  110  is turned within exhalation unit mount  502  in typical bayonet connection fashion. Optionally, one flange  160  may be provided having a shorter length than the remaining flanges  116 , and one of openings  504  may likewise have a shorter length than the remaining openings, to provide a proper alignment of removable cartridge assembly  100  when it is fitted into exhalation unit mount  502  of mask  500 . Moreover, a forward edge of each flange may optionally be tapered to further aid in the engagement of each flange with its intended ridge or shelf as cartridge body  110  is turned within exhalation unit mount  502 . To further aid in sealing removable cartridge assembly  100  in exhalation unit mount  502 , cartridge body  110  may also be provided channels  162  extending circumferentially around cartridge body  110  adjacent inlet side  1102 , with each channel  162  receiving a compressible seal  164 , such as an O-ring, to provide an air tight connection between the exterior of removable cartridge assembly  100  and the exhalation unit mount  502  of mask  500 . 
     Negative pressure valve  130  is positioned within the interior of cartridge body  110  and sits against a valve seat  117  (discussed in greater detail below), and front grill  120  sits within the open mouth at the outlet side  1101  of cartridge body  110 , frictionally held within cartridge body  110  so as to remain in place during use, but allowing removal without damage when intentionally pried away from cartridge body  110 . 
       FIG. 7  provides a front view of cartridge body  110  (i.e., viewing from the outlet side  1101 ) with front grill  120  removed, and  FIG. 8  provides a cross-sectional view of the cartridge body  110  of  FIG. 7  along section line A-A. An inlet end wall  112  is positioned at the inlet side  1102  of cylindrical wall  108  of cartridge body  110 , and includes a central hub  111  attached to inlet end wall  112  by a plurality of radial arms  113 . Radial arms  113  are spaced apart, such that openings  114  exist between each pair of radial arms  113 , allowing air to pass through the inlet end wall  112  and into the interior of cartridge body  110 . Central hub  111  also has a central opening  115  configured to receive the valve stem of negative pressure valve  130 , providing a removable connection of negative pressure valve  130  to the rest of the respirator exhalation unit. The interior, downstream side of the inlet end wall  112  also defines a valve seat  117  against which negative pressure valve  130  sits in a closed position (i.e., during inhalation into the mask  500 ), and away from which at least a portion of negative pressure valve  130  moves or deflects in an open position (i.e., during exhalation from the mask  500 ). The valve stem of valve  130  is removably received in a narrowed portion of hub central opening  115 , and as there is no other attachment between valve  130  and cartridge body  110  other than the frictional forces between the valve stem and hub central opening  115 , the valve  130  can be easily removed and replaced when worn, or simply moved to allow cleaning and clearing of the openings  114  if and when they become fouled with debris.  FIG. 9  provides a close-up view of section B of  FIG. 8 , particularly showing valve seat  117  extending upward from inlet end wall  112  and having a slightly curved outer edge, against which an underside of valve  130  sits to seal inlet side  1102  of cartridge body  110 . 
     After a user has performed any such required or desired maintenance, removable front grill  120  may be replaced into the front, outlet side  1101  of cartridge body  110 . To facilitate the proper, aligned placement of front grill  120  into cartridge body  110 , and as shown in both  FIG. 8  and the close-up view C shown in  FIG. 9 a   , a rounded, concave recess  118  extends around the circumference of cartridge body  110  adjacent outlet side  1101 , into which a rounded, convex edge  121  of front grill  120  may be snap-fitted for easy, removable attachment to cartridge body  110 . Likewise, longitudinal positioning spacers  119  are provided on the interior of cartridge body  110 , and may be sized so as to sit against the upstream side of front grill  120  when properly positioned within the open end of cartridge body  110 . 
       FIG. 11  provides a top view, and  FIG. 12  a side view, of front grill  120 . Likewise,  FIG. 13  provides a cross-sectional view of front grill  120  along section line A-A of  FIG. 11 . Front grill  120  has an outer diameter sized to fit within the open end of cartridge body  110  adjacent the outlet side  1101 . More particularly, and as referenced above, front grill  120  has a rounded, convex edge  121  at its outer-most circumferential edge, which convex edge  121  is configured to fit closely within concave recess  118  at the open end of cartridge body  110  in a snap-fit type of engagement, allowing the front grill  120  to be held firmly in place during use, but likewise allowing its intentional removal from cartridge body  110  without damage to the cartridge assembly  100  when desired for service purposes. Front grill  120  includes a central hub  122 , an outer rim  123 , and a plurality of radial ribs  124  connecting central hub  122  and outer rim  123 . One or more interior rims  125  may also be provided. Openings  126  exist between adjacent radial ribs  124 , which openings  126  allow air to pass through front grill  120 . Positioning tabs  127  are provided at the outer edge of front grill  120 , and align with notches  128  on cartridge body  110  to properly, angularly align front grill  120  within the open front of cartridge body  110 . Positioning ribs  127  are preferably sized so as to fit closely within notches  128 , providing a further frictional connection between front grill  120  and cartridge body  110 . 
     Next, and as shown in the exploded view of  FIG. 14  and the front, top, and side view of  FIGS. 15, 16, and 17 , respectively, removable cartridge assembly  100  may also be used in a negative/positive pressure valve system by providing a modified front grill  1200  and a spring-biased load disc  230 . In this system configuration, air pressure inside of mask  500  may be maintained slightly positive (with respect to ambient), such as when used with a PAPR or an SCBA, or alternatively may be maintained negative (again with respect to ambient), operating as set forth in the description above. When maintained in a positive pressure condition, while exhalation still occurs through the check valve in the exhalation unit, the check valve should have greater exhalation resistance than in the negative-only condition. Thus, and with reference to  FIGS. 14 through 17 , the removable cartridge assembly (shown generally at  100 ) includes a cartridge body  110  (in the same configuration as that described above), a front grill  1200 , and a negative pressure valve  130  (again configured as described above), along with a load disc spring  220 , an outlet valve load disc  230  that is biased by load disc spring  220  against valve  130  (the other end of load disc spring  220  being positioned against the interior face of front grill  1200 ), and a roll pin (lifting member)  240  that extends through a guide channel  234 , with cam surface as shown, in outlet valve load disc  230  so as to axially guide load disc  230  between a negative only position (in which it does not engage valve  130 ) and a positive position (in which it does engage valve  130 ). 
     In the negative/positive pressure valve system configuration, removable cartridge assembly  100  is again configured for removable placement within the exhalation unit mount  502  of a protective mask  500 , as shown in  FIG. 18  (showing removable cartridge assembly  100  about to be placed into the exhalation unit mount  502  of a protective mask  500 ) and  19  (showing removable cartridge assembly  100  seated within exhalation unit mount  502  of protective mask  500 ), all as described above with respect to the negative pressure only configuration. Moreover, and as discussed in greater detail below, a handle  202  is positioned on the downstream side of front grill  1200  and is positioned to sit forward of a front edge of exhalation unit mount  502  so as to allow a user to rotate front grill  1200  with respect to cartridge body  110  when it is installed within mask  500 . 
     As with the negative pressure only configuration described above with regard to  FIGS. 1 through 13 , negative pressure valve  130  is positioned within the interior of cartridge body  110  and sits against valve seat  117 , and front grill  1200  sits within the open end adjacent the outlet side  1101  of cartridge body  110 , frictionally held within cartridge body  110  so as to remain in place during use, but allowing removal without damage when intentionally pried away from cartridge body  110 . 
       FIG. 20  provides a top view and  FIG. 21  a bottom view of front grill  1200 . Likewise,  FIG. 22  provides a cross sectional view of front grill  1200  along section line A-A of  FIG. 20 , and  FIG. 23  provides a cross sectional view of front grill  1200  along section line B-B of  FIG. 20 . Further,  FIG. 24  provides a side view of front grill  1200 . As shown in  FIGS. 20 through 24 , front grill  1200  is configured similar to front grill  120 , but also includes a handle  202  affixed to outer rim  123 , and a central hub  204  extending axially toward the interior of cartridge body  110 . Handle  202  may be grasped by a user to rotate front grill  1200  with respect to cartridge body  110 , thus controlling the axial position of outlet valve load disc  230  as described in greater detail below. Central hub  204  is sized to fit within a central receiving hub  232  on outlet valve load disc  230  ( FIGS. 25-28 ) and roll pin  240  may be placed through an opening  206  in central hub  204  (and likewise through a guide channel in central receiving hub  232  of outlet valve load disc  230 ) to movably and removably attach outlet valve load disc  230  to front grill  1200 . 
       FIG. 25  is a top view (i.e., a view from the outlet side  1101  of cartridge body  110 ), and  FIG. 26  a side view, of outlet valve load disc  230 . Likewise,  FIG. 27  is a cross sectional view of outlet valve load disc  230  along section line H-H of  FIG. 25 , and  FIG. 28  is a cross sectional view of outlet valve load disc  230  along section line A-A of  FIG. 26 . As shown in  FIGS. 25 through 28 , outlet valve load disc  230  has a plurality of radially extending guide arms  236  that align with longitudinal positioning spacers  119  on the interior of cartridge body  110 . Thus, when outlet valve load disc  230  is positioned within cartridge body  110 , it is angularly locked in place with regard to cartridge body  110 , but can move axially within cartridge body  110 . However, as front grill  1200  is rotatable with respect to outlet valve load disc  230  and cartridge body  110 , rotation of front grill  1200  will cause roll pin  240  (whose angular position is locked with respect to front grill  1200 ) to angularly move with respect to outlet valve load disc  230 , riding within guide channel  234  and causing the axial position of outlet valve load disc  230  to change. Such axial movement of outlet valve load disc  230  within cartridge body  110  will likewise change its position with respect to valve  130 , thus allowing outlet valve load disc  230  to exert variable amounts of force on valve  130 , and enabling the change of the cartridge assembly  100  from a negative-only assembly to a positive pressure assembly. 
     Moreover, as front grill  1200  remains removable from cartridge body  110 , each of load disc spring  220 , outlet valve load disc  230 , and valve  130 , along with the interior of cartridge body  110 , all remain easily accessible for service or replacement as may be necessary, and their assembly within cartridge body  110  is configured so that each of such elements may be separately removed or replaced through minimal modification and without requiring replacement of the other elements of the removable cartridge assembly  100 . 
     Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It should be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.