turning now to the drawings in which like reference characters indicated corresponding elements throughout the several views , attention is restricted to fig1 which shows an inhalation mask embodying the teachings of the instant invention and generally designated by the reference character 20 . mask 20 includes body 22 , inhalation valve assembly 23 and exhalation valve assembly 24 . preferably , two inhalation valve assemblies 23 are included , one extending from either lateral side of body 22 . the single exhalation valve assembly 24 is located at a frontal midpoint . body 22 , as seen with additional reference to fig2 is generally cup - shaped , terminating with rearwardly directed peripheral edge 25 . edge 25 , as seen in cross section in fig2 a , comprises a terminal portion of body 22 , which is inturned to form a semi - cylindrical bead having inwardly directed free edge 27 . body 22 is sized to receive at least one of the external respiratory organs , such as the nose , of an individual as specifically illustrated in fig1 . edge 25 is contoured to be received against the facial area surrounding the nose . preferably , body 22 is molded of a flexible elastic material , such as the thermoplastic elastomer distributed under the trademark kraton ®. being of reduced thickness , the terminal portion forming peripheral edge 25 is readily deformable to be pliantly received against the facial area in sealing engagement therewith . in accordance with the immediately preferred embodiment of the invention , exhalation valve 24 includes integrally formed exhalation valve body 28 projecting outwardly from body 22 . bore 29 extending through tubular member 28 and body 22 and functioning as an outlet port , terminates with inlet end 30 and outlet end 32 . outwardly directed annular valve seat 33 , having annular ride 34 projecting therefrom , is formed in bore 29 proximate inlet end 30 . post 35 is coaxially held within bore 29 by a spider - like arrangement of support members 37 which extend radially between post 35 and the sidewalls of bore 29 intermediate valve seat 33 and inlet end 30 . valve disc 38 , preferably a relatively thin resiliently deformable member which may also be fabricated of a thermoplastic material , is carried by post 35 . annular groove 39 , functioning as an attachment receiving means as will be described presently , is formed coaxially into bore 29 proximate outlet end 32 . normally , valve disc 38 resides against valve seat 33 in the closed position as seen in fig3 . in response to inhalation of the individual , valve disc 38 is drawn with greater force into sealing engagement with annular ridge 34 . in response to exhalation of the individual , valve disc 38 deflects from valve seat 33 for exhaust of expired gases in the direction of arrowed lines a as seen in fig4 . accordingly , it is seen that disc 38 and valve seat 34 function as an outlet check valve for unidirectional flow of expired gas through outlet port 29 . each inhalation valve 23 includes an inhalation valve body 40 projecting from body 22 and having a bore therethrough defined by cylindrical sidewall 42 . inhalation valve body 40 projects angularly rearward from body 22 . accordingly , the outlet end 43 of bore 42 is generally eliptical , being askew to the longitudinal axis of bore 42 . the terminal portion of bore 42 adjacent end 43 functions as a valve seat for flapper member 45 which is hingedly affixed to body 22 . inhalation valve body 40 and flapper member 45 , analogous to post 35 and support members 37 , are integrally formed with body 22 . the peripheral edge 47 of flapper member 45 is shaped to be matingly received within the previously described valve seat . a respirable gas is transmitted to mask 20 from a source thereof through a delivery conduit , such as hose 48 . as will be appreciated by those skilled in the art , respirable gases for anesthetic and analgesic purposes , such as oxygen and nitrous oxide , are commonly employed in the medical and dental arts . as such , a pressurized supply of a selected gas is readily available in medical and dental facilities . delivery conduit 48 may be directly connected to inhalation valve body 40 . alternately , there is provided a connecting nipple 49 as particularly seen in fig3 . nipple 49 , a relatively rigid tubular member , is partially inserted into the inlet end of inhalation valve body 40 and partially into the outlet end of delivery conduit 48 . it should also be noted that mask 20 is molded in a single piece from a homogeneous elastomeric material . therefore , for purpose of this application , when the term integral is used to refer to an element , such as inhalation valve body 40 or exhalation valve body 28 , that element is molded into a single continuous structure of homogeneous material with body 22 to form mask 20 . expired gas emitted from exhalation valve 24 , when mask 20 is used as seen in fig1 is delivered to the ambient atmosphere . under certain circumstances it is desirable that the expired gas be captured for remote disposal . for this purpose , the prior art has provided various scavenging devices which cooperate with a source of vacuum generally available in medical and dental facilities . previously described mask 20 comprises a component of an inhalation system which further includes various accessory devices provided by the instant invention . mask 20 and each selected accessory device provide an inhalation apparatus which is adapted for use with a selected commercially available scavenging apparatus . referring now to fig7 there is seen an accessory device generally designated by the reference character 50 having cylindrical body 52 and outwardly directed annular flange 53 . the terminal portion of body 52 adjacent flange 53 is matingly receivable within bore 29 of exhalation valve 24 . flange 53 is matingly receivable within annular groove 39 . thus , it is seen that the terminal portion of body 52 and flange 53 function as attachment means for accessory device 50 , which is receivable within the attachment receiving means of valve assembly 24 . accessory device 50 functions as an adapter plug to sealingly close outlet port 39 and render exhalation valve assembly 24 inoperative . further , in accordance with the immediate embodiment of the invention , the flapper member associated with one of the inhalation valve assemblies 23 is removed . for purposes of illustration , the left hand flapper valve , as mask 20 is viewed in fig8 has been removed . an exhaust conduit 54 associated with a selected prior art scavenging system is secured to the respective inhalation valve body 40 . delivery conduit 48 is attached to the other inhalation valve assembly 23 with flapper member 45 intact as previously described . attention is now directed to fig9 and 10 which illustrate an alternate accessory device generally designated by the reference character 60 , including hollow cylindrical body 62 closed at the outboard end by endwall 63 to form chamber 64 therein . annular flange 65 encircles body 62 proximate the inboard end 66 thereof . analogous to the previously described embodiment , flange 65 and the exterior portion of cylindrical body 62 adjacent flange 67 function as attachment means to be received by the attachment receiving means of the exhalation valve assembly 24 of mask 20 . the attachment is further reinforced by locking ring 68 having bore 69 therethrough which is rotatably and slidably received upon body 62 and internal surface 70 which frictionally engages the exterior surface of tubular member 28 . nipple 72 projects radially from body 62 . opening 73 , functioning as an exhaust port , extends through nipple 72 and the sidewall of body 62 to communicate with chamber 64 . accessory device 60 serves to adapt mask 20 for use with another known prior art scavenging device as represented by the flexible conduit 74 seen in fig1 . with accessory device 60 attached , the check valve associated with exhalation valve assembly 24 remains fully operational . accessory device 60 functions as a manifold for receiving expired gases from body 22 and transferring said gases to flexible conduit 74 . delivery conduits 48 are connected with the inhalation valve assemblies 23 as previously described . another alternate accessory device , generally designated by the reference character 80 and usable in combination with the previously described mask 20 , is seen with reference to fig1 and 12 . the immediate embodiment includes hollow cylindrical body 82 closed at the outboard end by endwall 83 and having outwardly directed annular flange 84 proximate the inboard end 85 . chamber 67 resides within body 82 . nipple 88 projects from body 82 and includes bore 89 extending therethrough and communicating with chamber 67 . vent openings 90 project through body 82 for communication between chamber 67 and the ambient environment . accessory device 80 is connected with the exhalation valve assembly 24 of mask 20 as previously described and functions as an adapter whereby the inhalation apparatus is usable with yet another commercially available scavenging system . yet another accessory device , generally designated by the reference character 110 is illustrated in fig1 . the accessory device 110 includes tubular body 112 having an open outboard end 113 and an outwardly projecting annular flange 114 proximate inboard end 115 . accessory device 110 , which is securable to mask 22 as previously described , functions as an adapter for attachment of a scavenging valve assembly of the prior art designated by the reference character 117 . tubular connection member 118 associated with valve attachment 117 is frictionally received with the bore 119 of accessory device 110 . attention is now directed to fig1 and 15 which illustrate an accessory device generally designated 120 , attached to mask 20 . accessory device 120 includes a hollow cylindrical body 122 closed at the outboard end by endwall 123 to form a chamber 124 therein . an annular flange 125 encircles body 122 proximate the inboard end 126 thereof . the terminal portion of body 122 adjacent flange 125 has an annular groove 128 therein , and is matingly receivable within bore 29 of exhalation valve 24 . flange 125 is matingly receivable within annular groove 39 , while the terminal portion of exhalation valve 24 is matingly receivable within groove 128 . referring now to fig1 and 17 , nipples 129 project from body 122 , and include bores 130 extending therethrough and communicating with chamber 124 . vent openings 132 project through endwall 123 for communication between chamber 124 and the ambient environment . with further reference to fig1 , a central post 133 extends coaxially from endwall 123 into chamber 124 . inwardly directed annular valve seat 134 is formed in chamber 124 proximate endwall 123 . a valve disc 135 is carried by post 133 . normally , valve disc 135 resides against valve seat 134 in the closed position as seen in fig1 . this closes vent openings 132 preventing communication between chamber 124 and the ambient environment . valve disc 38 of exhalation valve 24 also resides against valve seat 33 in the closed position . in response to inhalation of the individual , valve disc 38 is drawn with greater force into sealing engagement with annular ridge 34 . in response to exhalation of the individual , valve disc 38 deflects from valve seat 33 for exhaust of expired gases into chamber 124 as illustrated in fig1 . during exhalation , the ingress of expired gases into chamber 124 forces valve disc 125 into sealing engagement with valve seat 124 , sealing chamber 124 from the ambient environment . scavenging conduits 138 then remove the expired gases from chamber 124 . this is the optimal situation , when the vacuum pressure is properly balanced with an individuals respiration . however , if the vacuum generated is to strong , during inhalation valve disc 38 would deflect from valve seat 33 causing the withdrawal of gases from mask 20 before they were inhaled if relief valve was not present . however , accessory device 120 prevents this as illustrated in fig2 . if the vacuum pressure is to strong , instead of deflecting valve disc 38 from valve seat 33 valve disc 135 is deflected from valve seat 134 . this allows the individual to properly inhale the gases while the vacuum withdraws air from the ambient environment through vent openings 132 . upon exhalation by the individual , valve disc 38 is deflected from valve seat 33 with expired gases being exhausted into chamber 124 forcing valve disc 135 into sealing engagement with valve seat 134 . referring now to fig2 , accessory device 120 is illustrated attached to mask 20 , and a vacuum scavenger apparatus generally designated 136 . in this embodiment , a pair of flexible hoses 138 extend from nipples 129 of accessory device 120 , to a two into one adapter 139 . a single hose 140 extends from adapter 139 to a vacuum source 142 . an adjustable gauge 143 is incorporated into vacuum hose 140 to allow the vacuum supplied to accessory device 120 to be adjusted . delivery conduits 48 extend from inhalation valve assemblies 23 to a two into one delivery adapter 143 . a single delivery conduit extends from adapter 143 to a gas source 145 . various changes and modifications to the embodiment herein chosen for purposes of illustration will readily occur to those skilled in the art . to the extent that such modifications and variations do not depart from the spirit of the invention , they are intended to be included within the scope thereof which is assessed only by a fair interpretation of the following claims .
a face mask includes a cup - shaped body for enclosing an external respiratory organ , such as the nose , of a patient . flow of a respirable gas into the body and exhaust of expired gas from the body are unidirectional controlled by respiration check valves . a plurality of detachably securable and interchangeable accessory devices adapt the mask for use with selected prior art scavenging devices .