Abstract:
A CPAP vent diffuser adapted to effectively seal around a vent of a CPAP mask comprises a chamber of porous cloth that moderates air flow from the vent of CPAP machine by increasing in the chamber walls the area the air flow has to move through thus decreasing the speed of the air.

Description:
BACKGROUND 
     1. Field of the Invention 
     This invention relates to apparatuses that assist breathing, usually during sleep, such as a CPAP system, that has a mask that covers a user&#39;s nose or both mouth and nose. More specifically, the invention relates to a gas diffuser adapted to connect around an outlet vent of the mask through which expired air from the user and an air pressure machine is exhausted. 
     2. Prior Art 
     Sleep apnea temporarily closes a user&#39;s air ways and causes the user to wake up, even if momentarily, as lack of oxygen is communicated to the brain. This lack of oxygen is dangerous and may cause high blood pressure and other cardiovascular disease, stroke, memory problems, weight gain, impotency, and headaches, according to the Sleep Apnea Association of America. 
     People with sleep apnea often use a CPAP (Continuous Positive Airway Pressure) system to keep air passages open while sleeping. The CPAP system includes a machine to regulate the air pressure delivered to the user through a hose, mask and head gear. There are many styles of masks, and the use of one over the other is determined by a person&#39;s preference. There are three types: full face, which covers the user&#39;s nose and mouth, over the nose, and “pillow” which has a cannula for each nostril and is associated with a soft form generally known as a pillow. Different styles exist in each type that involve different hose attachment designs. 
     All systems are vented through an outlet vent to allow carbon dioxide (CO 2 ) from exhalation to exhaust from the system. Air pressure is adjusted for a prescribed amount plus an amount for loss of pressure through the vent. It is common for air to come out of a mask outlet vent at a high flow rate. This exhaust, if directed toward the skin (i.e. an arm) or a sleeping partner, is uncomfortable. It feels cold and is a near continuous, concentrated blast of air that can wake a user from the sleep the machine was designed to obtain. The air flow is also noisy and disturbing to a sleeping partner. 
     It is therefore a primary object of the present invention to diffuse the high velocity air exhausting through the vent of the CPAP machine while maintaining necessary flow from the vent to prevent backpressure and CO 2 .buildup. It is a further object to quiet the flow from the outlet vent without introducing back pressure and CO 2  buildup. It is another object to employ a diffuser that is easy to use, install and clean. It is a further object that the diffuser be disposable without appreciable cost. For all purposes herein, the term ‘disposable” means the diffuser is inexpensive to replace. Inexpensive is deemed to mean the diffuser costs less than about 5% of the cost of the mask. 
     SUMMARY 
     The CPAP vent diffuser of the present invention operates to prevent exhausted air and exhaled CO 2  from the vent of a mask of a CPAP machine from causing a harsh rush of air being directed at the user or their mate that would disturb sleep without operationally impairing total flow of the expired air. This is done by providing a chamber into which air flows from the vent pushing out the diffuser walls that are larger than the vent through which air passes into the chamber, dispersing the flow of quickly moving air throughout the chamber, which consequently decreases the speed of the air flow to produce a more gentle flow of the exhausting air from the diffuser than from the vent while still allowing the air and exhaled CO 2  to escape the CPAP vent without impeding total air flow from the mask. 
     Typically, a hose connects a CPAP machine to the mask held over the user&#39;s nose or nose and mouth. The mask necessarily includes a hose through which air flow is fed into the mask which is exhausted from the mask&#39;s outlet vent along with a user&#39;s exhalation. For a full face mask and an over the nose mask, commonly, the vent is a hole in the tube extending outward on the mask to which the hose is connected. For a ‘pillow’ style mask, the vent is on the soft tube called a pillow with the vent directly across from the cannulas which extend from the tube and interface with the user&#39;s nose. The air pressure flows into the pillow, from a tube which connects the pillow from the hose. 
     The CPAP vent diffuser goes over the vent and is made of soft, slightly gathered, porous knit material (like tee shirt material). It is generally a tubular sheath with elastic circumferentially sewn around its ends to hold it in place with an effective air seal around the tube on each end of the vent. (It is recognized that there are numerous other means for closing diffuser ends around a tube; for these purposes, all such other means known in the art are included here by general reference and are deemed included in describing elastic, which is understood to be representative of such other means.) The CPAP vent diffuser allows the expired air with carbon dioxide exhalation to exhaust through the knit material and diffuses the stream of air flow from the mask vent to stop direct venting on the user or on a sleeping partner. 
     The construction of the CPAP vent diffuser begins with a rectangle of soft, porous, knit material larger in width than the circumference of the hose/tube/vent assembly, gathered at each end with elastic sewn into each end. The elastic is shorter than the cloth is wide so as it is put into the cloth, the cloth will gather. This gathering creates a space or chamber between the tube/vent of the CPAP machine and the diffuser. For a full face mask or over the nose mask use, opposite rectangle edges are then sewn together to form a tube with elastic around each tube end. Construction of the pillow style mask of the CPAP vent diffuser begins with a rectangle of soft, porous, knit material larger in width than the circumference of the hose/tube/vent assembly gathered at each end with elastic sewn into each end. However, in the center of the open rectangle is an oval opening of a size to accommodate the cannula which goes through the open oval before interfacing with the nostrils. 
     The diffuser is then slipped over hose/tube/mask assembly joint of a full face and nose style mask or the soft tube of a pillow style mask to cover the vent and allow the cannula to fit though the oval opening. Then the air hose is attached to the tube in both styles after the diffuser is installed. Diffusers for both mask styles are easily removed for cleaning and are typically machine washable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a CPAP mask typical of a full face mask of the prior art in use showing a mask vent in a tube extending outward on the mask to which an air hose is attached. 
         FIG. 2  is a front perspective view of a CPAP mask vent shown with the diffuser of the present invention. 
         FIG. 3  is a perspective view of the mask of  FIG. 1  showing a diffuser of the present invention installed thereon. 
         FIG. 4  is a perspective view of the diffuser shown installed in  FIG. 2 , shown expanded from air pressure within. 
         FIG. 5  is a perspective view of the diffuser of  FIG. 3  shown collapsed without internal air pressure about the mask tube. 
         FIG. 6  is a perspective view of a CPAP mask typical of a ‘pillow’ styled face mask of the prior art in use showing a mask vent in a side of a tube opposite a side of the tube from which cannulas extend for interfacing with a user&#39;s nose. 
         FIG. 7  is a perspective view of the mask of  FIG. 5  showing a diffuser of the present invention installed thereon with air pressure from air flow out of the vent inflating the diffuser into a chamber. 
         FIG. 8  is a side view of the diffuser of  FIG. 6  showing an opening through which cannulas closely fit. 
         FIG. 9  is a perspective view of the mask of  FIG. 3  showing an expandable diffuser with a generally tubular wall. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A CPAP system includes a machine (not shown) that generates air flow with a prescribed air pressure which air is propelled into the hose  100 , then through the tube  106 , and into a mask  102  that covers a user&#39;s nose or nose and mouth for inhalation. The expired air from the mouth or nose of a user that experiences sleep apnea flows back through the mask  102 , which feeds the expired air to the tube  106  where the air exits the system through a vent  104 . As previously noted, masks are commercially available in several designs and styles, including masks full face masks, over the nose masks, and ‘pillow’ masks. Such masks for addressing sleep apnea are well known in the art and need not be described separately herein, though the art of sleep apnea masks is deemed included hereby by reference. Of import to this disclosure is that the mask  102  necessarily has an air outlet vent  104  through which expired gases are exhausted from the mask during use. 
     The diffuser  10  of the present invention comprises a sheath  18  for use with a CPAP mask mask  102  with tube  106  and hose  100  and is adapted to fit around the air vent (or vents)  104  of the mask  102  establishing an effective air seal about the vent  104  such that expired air flowing from the vent  104  is received into the sheath  18 . The diffuser  10  presents with a surface area larger than the vent  104  defining a chamber  12  within. 
     The diffuser  10  is porous such that gases exhausted through the vent  104  are distributed within the chamber  12  and pass out of the chamber  12  moderating gas flow from the vent  104  which passes out of the chamber  12  through the diffuser  10 . The diffuser  10  may further comprise collapsing walls  16  and may at least partially inflate away from the vent  104  when expired gases flow into the chamber  12  under pressure of the air flow. The advantage gained is the air flow otherwise discharged directly from the vent  104  at a prescribed air pressure is disturbing outside the diffuser  10  at substantially reduced air flow rate by introducing the diffuser  10  between the vent  104  and the discharge of air to ambient surroundings. The reduced rate of air flow also results in a substantial reduction in noise generated at the vent  104 . The chamber  12  serves to absorb acoustic energy generated at the vent  104  as air is discharged from the tube  102  attached to the mask and further air discharged through the diffuser is discharged over a much larger area as the expired gases are exhausted substantially uniformly over the diffuser  10  under equal pressure and therefore at a much reduced flow rate per unit area which also minimizes noise from the air discharge in the ambient surroundings. 
     The prescribed air pressure coming out of the vent  104  inflates the diffuser  10  creating the chamber  12  such that air flow out of the vent  104  is not substantially inhibited, in which case the diffuser  10  may at least partially inflate during flow of gases from the vent  104  and at least partially deflate during lack of flow from the vent  104  without gas back flowing into the vent  104  from the chamber, although the inflating may be small depending on the rate of flow from the vent  104 . The porous diffuser  10  slows the air flow as the air passes through the material. 
     The diffuser  10  is generally tubular for use with a CPAP mask  102  that has its vent  104  in tube  106  extending from the mask  102 , wherein ends  20 ,  22  of the tubular diffuser are closed on opposite sides  24 ,  26  of the vent  104  therein closing diffuser  10  about the vent  104 . The ends  20 ,  22  of the tubular diffuser  10  are fit with elastic  28  (or other closing means) such that they expand sufficiently to conveniently slide the diffuser  10  over the tube  106  and the vent  104  in the tube  106  and constrict to close the ends  20 ,  22  in an effective air seal. Thus, the diffuser  10  is quickly removable by disconnecting the hose  100  from the tube  106 , installing the diffuser  10  over the vent  104  and re-installing the hose  100  to the tube  106  without otherwise requiring disassembly of the CPAP system. 
     It should be appreciated that the diffuser  10  of such simple and inexpensive construction is disposable and amenable to easy cleaning such as washing. 
     It is to be understood that variations in size, materials, chamber shape and form, general assembly that could be devised in implementing this disclosure are deemed obvious to one skilled in the art. Therefore, the description is considered as representative of these possible variations, which are deemed to be included by the above description of the present invention.