Exhalation valve assembly

Abstract

An exhalation valve assembly for use in a volume ventilator circuit is disclosed. The valve assembly comprises a valve body defining a chamber with a gas inlet conduit and a gas outlet conduit, both in flow communication with the chamber. A diaphragm extends across the chamber and selectively closes off the gas inlet conduit. Upwardly extending strut members are disposed on an inside surface of the valve body and are used to position a removable ring member adjacent the diaphragm. The ring member is configured so as to support a portion of the diaphragm over the chamber.

What is claimed: 
     
       1. A valve assembly for use in a volume ventilator, comprising: (a) a valve body in part defining a pressure chamber.Iadd., said valve body having an annular diaphragm seat.Iaddend.;   (b) a gas inlet conduit joined to and in flow communication with said pressure chamber for directing a gas into said pressure chamber, said gas inlet conduit forming a discharge port in said pressure chamber;   (c) a gas outlet conduit joined to and in flow communication with said pressure chamber for directing gas out of said pressure chamber;   (d) diaphragm means removably disposed in and extending across said valve body adjacent said discharge port for selectively closing off said discharge port, said diaphragm means defining the remainder of said pressure chamber;   (e) a removably disposed ring member extending into said pressure chamber from a position adjacent the periphery thereof;   (f) a plurality of positioning members disposed on said body for positioning said ring member in said pressure chamber such that said ring member supports a predetermined portion of said diaphragm means; and   (g) a cover having a gas inlet joined to said valve body and extending across said diaphragm means on the opposite side thereof from said pressure chamber.Iadd.;   (h) said cover having an annular lip and said diaphragm means is sealed at its periphery between said annular lip and said diaphragm seat; and   (i) the removably disposed ring member interfitting with a portion of the diaphragm means and the valve body such that by removing said ring member a valve assembly having a substantially different valve area ratio may be achieved, permitting the valve assembly to be used in different volume ventilator circuits.Iaddend..   
     
     
       2. A valve according to claim 1 wherein said chamber is cylindrical and said discharge port is centrally disposed in said chamber. 
     
     
       3. A valve according to claim 1 wherein said positioning means comprises a plurality of strut members. 
     
     
       4. A valve according to claim 1 wherein the ratio of the area of said diaphragm means extending across said pressure chamber to the area of said discharge port is approximately 2:1. 
     
     
       5. A valve according to claim 1 wherein said ring member supports a portion of said diaphragm means such that the ratio of the unsupported area of said diaphragm means extending across said pressure chamber to the area of said discharge port is approximately from 1:1 to 2:1. 
     
     
       6. A valve according to claim 1 wherein said positioning members comprise a plurality of strut members located on said valve body, and said ring member is removably disposed on said strut members. 
     
     
       7. A valve according to claim 1 wherein said diaphragm means includes a section which is positioned between said cover and said ring member. .Iadd. 
     
     
       8.  A valve assembly for use in a volume ventilator, comprising: (a) a valve body in part defining a pressure chamber, said valve body having an annular diaphragm seat;   (b) a gas inlet conduit joined to and in flow communication with said pressure chamber for directing a gas into said pressure chamber, said gas inlet conduit forming a discharge port in said pressure chamber;   (c) a gas outlet conduit joined to and in flow communication with said pressure chamber for directing gas out of said pressure chamber;   (d) diaphragm means removably disposed in and extending across said valve body adjacent said discharge port for selectively closing off said discharge port, said diaphragm means defining the remainder of said pressure chamber;   (e) a removably disposed ring member extending into said pressure chamber from a position adjacent the periphery thereof;   (f) a plurality of positioning members disposed on said body for positioning said ring member in said pressure chamber such that said ring member in said pressure chamber such that said ring member supports a predetermined portion of said diaphragm means;   (g) said ring member being of substantial area, thus significantly decreasing the effective area of the diaphragm means with respect to the area of the discharge port, and in turn decreasing the valve area ratio; and   (h) a cover having a gas inlet joined to said valve body and extending across said diaphragm means on the opposite side thereof from said pressure chamber, said cover having an annular lip and said diaphragm means is sealed at its periphery between said annular lip and said diaphragm seat; and   (i) by removing said ring member a valve assembly having a substantially different valve area ratio may be achieved..Iaddend. .Iadd.9. A valve assembly according to claim 8 wherein, when the ring member is removed, the effective area of the diaphragm means with respect to the discharge port is substantially changed, significantly increasing the valve area   
     
     
        ratio..Iaddend. .Iadd.10.  A valve assembly according to claim 8 wherein said ring member includes a portion that extends into said pressure chamber and mates with a section of the diaphragm means, said ring member thereby substantially changing the amount of force required to disengage the diaphragm from said discharge port..Iaddend. .Iadd.11. A valve assembly according to claim 8 wherein the plane defined by the inner portion of the ring member is laterally offset from the plane defined by the rim of the ring member, said laterally offset inner portion of the ring member supporting said predetermined portion of said diaphragm means thereby occluding said portion of the diaphragm from extending across said discharge port..Iaddend. .Iadd.12. A valve assembly according to claim 11 wherein said ring member is positioned between said diaphragm means and said discharge port, and wherein said diaphragm means includes a section extending away from said discharge port and configured to arch over said ring member..Iaddend.