Respiratory mask having gas washout vent and method for making the mask

Abstract

A washout vent for a mask for use with a system for supplying breathable gas pressurized above atmospheric pressure to an airway of a mammal. The washout vent includes a vent orifice adapted for gas washout. The orifice includes one or more features that contribute to noise reduction, such as a channel with converging walls towards atmosphere, and/or a channel having one or more walls provided with surface treatment and/or contouring, such as roughening and/or scalloped portions.

What is claimed is: 
     
         1 . A washout vent for a mask for use with a system for supplying breathable gas pressurized above atmospheric pressure to an airway of a mammal, the washout vent comprising:
 a vent orifice adapted for gas washout, wherein said orifice includes opposed edges or side walls defining at least a portion of a conic section.   
     
     
         2 . A vent as in  claim 1  wherein orifice defines a solid section of the vent in the form of a peninsula. 
     
     
         3 . A vent as in  claim 1  wherein the vent orifice comprises a semi-circular slot extending approximately 270 degrees. 
     
     
         4 . A vent as in  claim 1  wherein the conic section defines a hyperbola, parabola, ellipse, circle, any portion thereof, or any combination thereof. 
     
     
         5 . A vent as in  claim 1  wherein the vent orifice is at an apex of a ridge on the mask. 
     
     
         6 . A vent as in  claim 5  wherein the orifice exit is in a plane offset from the mask. 
     
     
         7 . A vent as in  claim 6  wherein the orifice exit is in a plane common to the mask. 
     
     
         8 . A vent as in  claim 5  wherein the ridge is curvilinear in length. 
     
     
         9 . A vent as in  claim 1  wherein the vent is provided in an insert attachable to the mask. 
     
     
         10 . A vent as in  claim 1  wherein the orifice is substantially crescent-shaped. 
     
     
         11 . A vent as in  claim 1  wherein the orifice is one of a plurality of orifices therethrough. 
     
     
         12 . A vent as in  claim 1  wherein the orifice has a horse-shoe shape. 
     
     
         13 . A vent as in  claim 1  wherein the orifice comprises convex and concave segments. 
     
     
         14 . A vent as in  claim 1  wherein the orifice comprises a plurality of semi-circular segments. 
     
     
         15 . A vent as in  claim 1  wherein the orifice is a partial circle and partially surrounds a peninsula portion of the mask. 
     
     
         16 . A vent as in  claim 1  further comprising a channel between the orifice exit and an interior surface of the mask. 
     
     
         17 . A vent as in  claim 16  wherein the channel has a depth at least as thick as a thickness of the mask. 
     
     
         18 . A vent as in  claim 16  wherein the channel has a depth at least five times larger than a width of the orifice exit or minimum. 
     
     
         19 . A vent as in  claim 16  wherein the channel comprises sloping side walls. 
     
     
         20 . A vent as in  claim 16  wherein the slide walls have a slope of 5 degrees from an axis of the channel.