Abstract:
A humidification device ( 10 ) for use with a CPAP unit ( 18 ) or similar breathing device is provided which includes a stationary cabinet ( 12 ) with a slide-type drawer member ( 14 ) adapted to hold a supply of humidifying water. The cabinet ( 12 ) includes an input ( 28 ) and an output ( 30 ) allowing connection of CPAP device conduits ( 100, 102 ) respectively for delivering air to the humidifying device ( 10 ), and for delivering humidified output air to a patient. Use of the sliding drawer member ( 14 ) facilitates filling of the device ( 10 ) with water and periodic cleanup thereof. In alternate embodiments, electrical resistance heaters ( 84, 86 ) are secured to the drawer member ( 14 ). Mating electrical connectors ( 42, 94 ) respectively mounted on the cabinet ( 12 ) and drawer member ( 14 ) provide electrical power to the heaters for water heating purposes.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is broadly concerned with humidification devices for creating contact between an incoming gas stream and a supply of water to produce a humidified gas output. More particularly, the invention pertains to such humidification devices, especially in combination with an overall gas delivery assembly such as a CPAP (continuous positive airway pressure) unit, wherein the humidifier includes a slidable drawer member allowing easy access for filling and cleanup of the humidifier. 
     2. Description of the Prior Art 
     Sleep Apnea Syndrome is a disorder characterized by cessation of breathing and frequent awakenings during sleep. One class of sleep apnea is obstructive sleep apnea, which is characterized by the obstruction of the person&#39;s upper airway resulting in interference with breathing during sleep. In order to treat obstructive sleep apnea, CPAP devices have been developed to deliver air under constant positive pressure to the nasal passages during sleep. These devices are frequently successful in treating sleep deprivation due to obstructive sleep apnea. 
     In order to prevent drying of the breathing passages during the administration of CPAP, it is desirable to humidify the air supplied to the person using such devices. This may be accomplished by providing a humidifier which is essentially a bottle containing a quantity of water over which the air under pressure passes before being delivered to the user. The user partially fills the bottle with water, and the air is circulated within the bottle to pass over the surface of the water and absorb moisture therefrom. 
     U.S. Pat. No. 5,231,979 describes a CPAP humidifier in the form of an essentially completely enclosed body having tubular air input and output elements adjacent the forward end of the body. In order to fill the humidifier body, it is necessary to carefully pour water through one of the tubular ports until the water reaches a predetermined level. This can be troublesome and lead to water spillage. In addition, it can be difficult to clean such an enclosed humidifier body, particularly after a period of heavy use. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the problems outlined above and provides an improved humidifier for creating contact between an incoming gas stream and a supply of water so as to yield a humidified gas output stream. The humidifier is especially designed for use in conjunction with CPAP units, but may also be used with virtually any type of breathing device where humidification is desirable, e.g., ventilators. 
     Broadly speaking, the humidifier of the invention includes first and second slidingly interfitted members, with the second member preferably being somewhat drawer-like and adapted to hold a supply of water. The members are relatively shiftable between an open position permitting filling of the second member with water and a closed, humidifying position wherein the members cooperatively define a air-water plenum chamber. A gas input and a gas output are in communication with the plenum chamber so as to direct gas into, through and out of the plenum chamber for humidification thereof. 
     In preferred forms, the first member is in the form of a stationary cabinet whereas the second member comprises an open-top, water-holding drawer member. A connection assembly including mating components on the cabinet and drawer member respectively is provided for slidingly supporting the drawer member within the cabinet and permits sliding movement of the drawer member between its open and closed positions. Advantageously, the connection assembly includes a slide track supported on the cabinet whereas the drawer member has a slider which is received within the cabinet slide track. Certain embodiments of the present invention include a projection in the cabinet located at the end of the slide track. This projection mates with a recessed region of the drawer member and operates as an abuttment against which the drawer contacts when inserted into the cabinet, thereby limiting further insertion of the drawer once the drawer is properly inserted into the cabinet. Other embodiments utilize a beveled drawer which is slidingly received by a cooperatively beveled cabinet. In this embodiment, the beveled drawer permits drawer insertion into the cabinet without interference from the sliding track. When the drawer is fully inserted into the cabinet, the beveled portions of the drawer engage the cooperatively beveled portions of the cabinet, thereby limiting further insertion of the drawer. 
     In alternate embodiments, the drawer member includes one or more resistance heaters for heating water contained therein. In this embodiment, mating electrical connectors are located on the cabinet and drawer so that, when the drawer is fully inserted within the cabinet, the connectors mate to complete a heating circuit. 
     The gas delivery devices (e.g., CPAP units) of the invention are designed to generate and receive patient gas and to convey such gas along a path of travel for ultimate delivery to the patient. The humidifier of the invention is designed with its gas input and output for coupling into the path of travel of gas. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view with parts broken away illustrating the components of the preferred humidifier device of the invention; 
     FIG. 2 is a top view of the humidifier device in its closed position with parts broken away to reveal internal construction details; 
     FIG. 3 is a vertical sectional view of a humidifier device similar to that depicted in FIG.  2  and illustrating a CPAP unit positioned atop the humidifier and operably coupled thereto, where the humidifier device includes water heating elements; 
     FIG. 4 is a vertical sectional view taken along line  4 — 4  of FIG.  3  and further illustrating details of the humidifier and associated CPAP device; 
     FIG. 5 is a vertical sectional view taken along line  5 — 5  of FIG.  3  and depicting the internal construction of the humidifier device; 
     FIG. 6 is a bottom view with parts broken away of the FIG. 3 humidifier device, illustrating the electrical circuitry associated with the humidifier heater; 
     FIG. 7 is an exploded perspective view with parts broken away illustrating the components of another preferred embodiment of the humidifier device of the invention; 
     FIG. 8 is a vertical sectional view of the embodiment of FIG. 7, illustrating a CPAP unit positioned atop the humidifier and operably coupled thereto, where the humidifier device includes water heating elements; 
     FIG. 9 is a sectional view of the cabinet illustrating the tapered top wall and a plan view of the drawer separated from the cabinet; and 
     FIG. 10 is a bottom view with parts broken away of the FIG. 9 humidifier device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings, and humidifier device  10  in accordance with the invention broadly includes two slidingly interfitted members, namely a cabinet  12  and an open-top drawer member  14 . The member  14  is designed to be received within cabinet  12  and is relatively shiftable between an open position permitting filling of the member  14  with water and a closed, humidifying position wherein the cabinet and drawer member cooperatively define an internal, enclosed air-water plenum chamber  16 . The device  10  may be used in a variety of contexts, but is especially adapted for use with an otherwise conventional CPAP unit  18 , so that pressurized air from the unit  18  is directed into and through the humidifier device  10  before delivery to a patient. 
     In more detail, the cabinet  12  is preferably an integral body formed of an appropriate synthetic resin material, having a top wall  20  as well as a depending sidewalls  22 ,  24  and end wall  26 . As best seen in FIG. 1, the walls  22 - 26  project above the upper surface of top wall  20 . The top wall is configured with a tubular air inlet  28  and a spaced, tubular air outlet  30  adjacent the front open end of the cabinet and which communicate with the interior thereof. The inner or lower face of top wall  20  has an elongated, centrally located sliding track  32  formed of a pair of elongated, somewhat L-shaped projections  34 ,  36 . In some embodiments, top wall  20  includes an inwardly extending, somewhat trapezoidally shaped projection  38  disposed rearwardly of the inner end of track  32 . This projection provides an abutment which limits insertion of member  14 . 
     In the embodiment of FIGS. 3-6, a circuit box  40  including an electrical connector  42  is secured to the inner face of top wall  20  rearward of projection  38 . The box  40  is adapted to be coupled with a conventional power source and is designed to control the operation of the drawer member heaters later to be described. 
     The cabinet  12  has four tubular, internally threaded connectors  44  at approximately the corners thereof. A base plate  46  is secured to the connectors  44  by means of screws  48 , to complete the cabinet  12 . The lower face of base plate  46  is equipped with corner-mounted support feet  50  as shown. As best seen in FIG. 3, the cabinet  12  is thus a substantially enclosed body, except for a generally rectangular drawer member entrance opening  52  at the forward end thereof. 
     The drawer member  14  as indicated is adapted to be slidingly received within cabinet  12 . The drawer member is in the form of a molded synthetic resin body presenting a bottom wall  54  and an upstanding, circumscribing sidewall  56  to thereby define a water holding area  58 ; the rear segment of sidewall  56  includes a recessed region  59  adapted to mate with cabinet projection  38  and permit insertion of drawer  14  past sliding track  32  without obstruction between sidewall  56  and track  32 . Additionally, mating of recessed region  59  and cabinet projection  38  provides a seal between cabinet  12  and drawer  14 . It will be observed that the bottom wall  54  includes an elongated, upstanding hollow slider  60  having a continuous sidewall  62  and top wall  64 . The side margins of top wall  64  extend beyond the sidewall  62  a short distance to define laterally projecting flanges  66 ,  68 . As best seen in FIG. 4, the flanges  66 ,  68  are adapted for sliding reception within the projections  34 ,  36  making up slide track  32 . 
     The drawer member  14  also includes a forward ledge segment  70  defined by an upstanding wall portion  72  and horizontally extending shelf wall  74  leading to and merging with the sidewall  56 . The ledge segment  70  supports a pair of opposed, upwardly extending engagement walls  76 ,  78 . As illustrated, the rearward axially extending ends of the walls  76 ,  78  include respective flange projections  80 ,  82  which are oriented to fit within the forward ends of the cabinet projections  34 ,  36 . 
     The drawer member  14  of the FIGS. 3-6 embodiment is equipped with a pair of elongated, plate-like heaters  84 ,  86  which are respectively adhered to the underside of bottom wall  54  astride the hollow opening defined by upstanding projection  60  (see FIG.  5 ). The heaters  84 ,  86  include an internal resistance heating element  84   a ,  86   a  which are interconnected by lead  88 . Additionally, leads  90 ,  92  extend from the heating elements  84   a ,  86   a  to a rigidly mounted electrical connector  94  mounted on the rear segment of sidewall  56 . The connector  94  is designed to mate with connector  42  when drawer member  14  is slid into cabinet  12 . 
     The upper margin of drawer member sidewall  56  includes a continuous rubber-like resilient seal  96  which extends about the entire periphery of the drawer member. The seal  96  is adapted to engage the underside of cabinet top wall  20  when the drawer member is operatively inserted into the cabinet  12 . 
     The CPAP device  18  is of conventional design and is adapted to sit atop the humidification device  10  on cabinet top wall  20 . The CPAP device  18  is designed to deliver positive pressure air from a main housing  98  to inlet  28  via conduit  100 . As shown, the conduit  100  is coupled with humidifier inlet  28 . Another conduit  102  is coupled with humidifier outlet  30  and leads to a patient. A variety of different CPAP devices have been developed in the past and are well known to those skilled in the art. 
     Another embodiment of the CPAP device  18  of the present invention is illustrated in FIGS. 7-10. In this embodiment, cabinet  12  is formed without projection  38  and drawer  14  is formed without recessed region  59 . Therefore, in order to limit insertion of drawer  14 , drawer  14  is provided with a beveled or tapered sidewall  104 , best seen in FIG. 9, which engages the cooperatively beveled or tapered underside of cabinet top wall  106  when drawer  14  is properly inserted into cabinet  12 . A continuous rubber-like resilient seal  108  is included atop sidewall  104 . Advantageously, circumscribing beveled sidewall  104  permits insertion of drawer  14  into cabinet  12  without interference from slide track  32 . The cooperatively tapered sidewall  104  and top wall  106  also permit drawer  14  to be inserted into cabinet  12  without obstruction between sidewall  104  and track  32 . Accordingly, sidewall  104  is angled slightly downward from front sidewall portion  110  to rear sidewall portion  112 . Alternatively, seal  108  may be slightly thicker near portion  112  in order to account for the downward slope of sidewall  104  and engage top wall  106 , thereby preventing passage of water from drawer member  14 . 
     In the use of humidifying device  10 , it will be assumed that the CPAP device  18  is sitting atop cabinet  12  as shown in FIGS. 3-4, with the conduits  100 ,  102  connected as shown. The user first grasps drawer member  14 , typically by placing the fingers beneath ledge segment  70  and behind the forward portion of drawer sidewall  56 . The drawer member  14  is then pulled outwardly until the water holding area  58  becomes accessible. This area is filled with water up to approximately the level of ledge segment  70  whereupon the user pushes the drawer member back into its recessed position within cabinet  12 . As this occurs, the seal  96 ,  108  prevents passage of water from the drawer member  14 . As the drawer member assumes its operative position depicted in FIGS. 3 and 8, the connector  94  mates with connector  42 , thus establishing an electrical connection between circuitry  40  and the heaters  84 ,  86 . These heaters can then be actuated, typically through a conventional on-off switch (not shown). The heaters  84 ,  86  warm the water within area  58 . 
     The user then dons a CPAP nose mask or other similar device, which is coupled to the remote end of conduit  102 . As pressurized air from the CPAP device  18  is generated, it is passed through conduit  100  and inlet  28  into plenum chamber  16  where it is humidified in the presence of the water therein. Humidified air exits from outlet  30  and is conveyed to the patient via conduit  102 . 
     In the embodiment of FIGS. 1-2 which does not include the heaters and its associated hardware and circuitry, the use is similar, except that when the drawer member  14  is slid into cabinet  12 , there is no electrical component interconnection and thus no heating of the water within the drawer member.