Abstract:
A bubble humidifier for adding humidity to supplied oxygen. The bubble humidifier has a humidifier base, for containing a quantity of liquid, and a cover for the humidifier base. The bubble humidifier has an oxygen inlet for supplying oxygen to the bubble humidifier and an moisturized oxygen outlet for connection to a moisturized oxygen supply conduit for supplying humidified oxygen to a patient, and the oxygen inlet being connected to a diffuser for diffusing the supplying oxygen within the bubble humidifier. The bubble humidifier has a pressure relief device for relieving excess pressure generated within the bubble humidifier during operation thereof. The bubble humidifier defining a longitudinal axis and the diffuser is arranged to discharge the oxygen from the diffuser substantially at an angle normal to the longitudinal axis of the bubble humidifier to minimize flow of liquid, contained within the humidifier base, from entering the moisturized oxygen outlet during operation of the bubble humidifier.

Description:
FIELD OF THE INVENTION 
     The present invention relates to improvements concerning a bubble humidifier used to humidify oxygen prior to dispensing the oxygen to a patient for medical purposes. 
     BACKGROUND OF THE INVENTION 
     Oxygen is supplied to patients for a variety of medical reasons. The conventional techniques for generating oxygen typically remove essentially all of the moisture from the generated oxygen so that the oxygen essentially has zero percent relative humidity. Prior to supplying the generated oxygen to a patient, the oxygen is generally sent through a bubble humidifier, or some other humidifying apparatus, where a suitable amount of humidity is added to the oxygen prior to supplying the same to the patient for a medical application. 
     Standard humidifiers typically operate well for humidifying oxygen at an oxygen flow rate of from about 2 to 4 liters per minute. However, when the flow rate of the supplied oxygen is increased to 6 liters per minute or greater, the currently available bubble humidifiers do not work satisfactorily. In particular, the currently available bubble humidifiers have a tendency to jiggle and shake excessively due to the increase in the oxygen flow rate through the bubble humidifier. Such jiggling or shaking of the bubble humidifier, in turn, has a tendency to cause a valve component of the pressure relief device for the bubble humidifier to become unseated and vent a portion of the moisturized oxygen from the bubble humidifier to the surrounding environment rather than the supplying the same to the patient. Such venting of the supplied oxygen, via the pressure relief device, also causes the pressure relief device to emit a “whistling” sound. This sound generally indicates that at least a portion of the supplied moisturized oxygen is not being conveyed to the patient, e.g., the moisturized oxygen supply conduit for supplying the oxygen to the patient may have a kink therein or is somehow clogged or occluded. In response to the “whistling” sound, the medical personnel will then undertake corrective action, e.g., remove the kink or occlusion from the moisturized oxygen supply conduit. 
     The conventional pressure relief devices work reasonably well for low oxygen flow rates, e.g., flow rates of 4 liters per minute or less. However, when the flow rate of the oxygen is increased to 6 liters per minute or greater, the conventional pressure relief devices have a tendency to malfunction as the valve of the pressure relief device does not always properly reseat itself to ensure that all of the supplied moisturized oxygen is again conveyed to the patient, via the moisturized oxygen supply conduit, rather than being vented to the surrounding environment 
     The increased oxygen flow rate also has a tendency to cause the oxygen bubbles to coalesce and when the coalescing bubbles filter up through the liquid contained in the bubble humidifier and break the liquid surface. Upon breaking the liquid surface, liquid is splashed and sprayed toward the outlet of the bubble humidifier and into the moisturized oxygen supply conduit. This splashed and sprayed liquid, e.g., water, is then conveyed along with the moisturized oxygen toward a cannula, connected at a remote end of the moisturized oxygen supply conduit, which supplies the moisturized oxygen into the nostrils of a patient. A water trap is installed, along the moisturized oxygen supply conduit, to remove small quantities of liquid from the moisturized oxygen. The conventional water traps work adequately for removing small amounts of water from the moisturized oxygen supply conduit, but the water trap can become quickly clogged if a large quantity of liquid enters the moisturized oxygen supply conduit and is conveyed toward the patient. 
     SUMMARY OF THE INVENTION 
     Wherefore, it is an object of the present invention to overcome the above mentioned shortcomings and drawbacks associated with the prior art bubble humidifiers. 
     Another object of the present invention is to provide a bubble humidifier which is able to add a sufficient amount of moisture to oxygen for a medical application, while minimizing the amount of liquid, e.g., water, which enters into the moisturized oxygen supply conduit exiting from the bubble humidifier. 
     A further object of the present invention is to provide a pressure relief device which reliably indicates when there is a blockage, kink or some occlusion in the moisturized oxygen supply conduit and also facilitates proper reseating of the valve element once the blockage, kink or occlusion is eliminated from the moisturized oxygen supply conduit. 
     Yet another object of the present invention is to minimize the amount of liquid that enters into the moisturized oxygen supply conduit and must be removed by a water trap to minimize the associated maintenance required for use of the bubble humidifier. 
     A still further object of the present invention is to provide a larger bubble humidifier surface area for the bubbles emitted by the diffuser to facilitate a greater and improved dispersion of the oxygen bubbles emitted by the. 
     Yet another object of the present invention is to minimize the coalescence of the bubbles as they contact the side wall of the container so as to minimize the amount of turbulence of at the surface of the liquid as the oxygen bubbles migrate up through the liquid contained in the bubble humidifier during operation. 
     The present invention also relates to a bubble humidifier for adding humidity to supplied oxygen, the bubble humidifier comprising: a humidifier base for containing a quantity of liquid; a cover for the humidifier base; the bubble humidifier having an oxygen inlet for supplying oxygen to the bubble humidifier and a moisturized oxygen outlet for connection to a moisturized oxygen supply conduit for supplying humidified oxygen to a patient, and the oxygen inlet being connected to a diffuser for diffusing the supplying oxygen within the bubble humidifier; the bubble humidifier having a pressure relieve device for relieving excess pressure generated within the bubble humidifier during operation thereof; and the bubble humidifier defining a longitudinal axis; wherein the diffuser is arranged to discharge the oxygen from the diffuser substantially at an angle normal to the longitudinal axis of the bubble humidifier to minimize flow of liquid, contained within the humidifier base, from entering the moisturized oxygen outlet and being conveyed along the moisturized oxygen supply conduit during operation of the bubble humidifier. 
     The present invention also relates to a method of adding humidity to supplied oxygen via the bubble humidifier, the method comprising the steps: providing a humidifier base containing a quantity of liquid; covering the humidifier base with a cover; providing the bubble humidifier with an oxygen inlet for supplying oxygen to the bubble humidifier, connecting an moisturized oxygen outlet to a moisturized oxygen supply conduit for supplying humidified oxygen to a patient, and connecting the oxygen inlet to a diffuser for diffusing the supplying oxygen within the liquid contained by the humidifier base; providing the bubble humidifier with a pressure relieve device for relieving excess pressure generated within the bubble humidifier during operation thereof; defining a longitudinal axis with the bubble humidifier; discharging, via a diffuser, the oxygen from the diffuser substantially at an angle normal to the longitudinal axis of the bubble humidifier to minimize flow of liquid, contained within the humidifier base, from entering the moisturized oxygen outlet and being conveyed along the moisturized oxygen supply conduit during operation of the bubble humidifier. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
     FIG. 1 is a diagrammatic view showing an application for the bubble humidifier of the present invention; 
     FIG. 2 is an exploded diagrammatic perspective view of the cover for the bubble humidifier of FIG. 1; 
     FIG. 3 is a diagrammatic cross-sectional view showing the pressure relief device incorporated within the cover of the bubble humidifier shown in its normally closed position; 
     FIG. 4 is a diagrammatic cross-sectional view showing the pressure relief device incorporated within the cover of the bubble humidifier shown in its normally opened position with the slug being lifted from its seating engagement with the relief port to remove excess pressure from bubble humidifier; 
     FIG. 5 is a diagrammatic exploded view of the slug incorporated within the pressure relief device of FIG. 3; 
     FIG. 6 is a diagrammatic elevational view of the diffuser incorporated within the bubble humidifier for diffusing the oxygen prior to moisturizing the oxygen; 
     FIG. 7 is a diagrammatic top plan view of the diffuser of FIG. 6; 
     FIG. 8 is a diagrammatic cross sectional view of the diffuser along section line  8 — 8  of FIG. 7; 
     FIG. 9 is a diagrammatic end view of the diffuser  8  along section line  9 — 9  of FIG. 8; and 
     FIG. 10 is a diagrammatic perspective view of the diffuser of FIG.  6 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to FIG. 1, a brief description concerning the basic components of the present invention will now be discussed. As can be seen in this Figure, the bubble humidifier  2  generally comprises a removable cover  4  which sealingly engages with a humidifier base  6  of the bubble humidifier  2  either by a pair of mating screw threads (not shown) carried by the cover  4  and the humidifier base  6  or any other coupling arrangement which is conventional or well known in the art. The humidifier base  6  is designed to hold a sufficient amount of liquid  22 , i.e., water. The cover  4  has a centrally located oxygen inlet  8  and an oxygen outlet  10  as well as pressure relief device  12 , the function of which will be discussed below in further detail. An outlet of the oxygen generator or source  16  is connected to the oxygen inlet  8  in a conventional manner, e.g., by a threaded wing nut coupling or the like for example. The oxygen source  16  generates a sufficient supply of oxygen and conveys the generated oxygen to the bubble humidifier  2 . A diffuser  18  is located within the bubble humidifier  2  and a first end of a humidifier conduit  20  is connected to the oxygen inlet  8 , to receive the oxygen conveyed by the flexible oxygen source conduit  14 , while a second opposed end of the humidifier conduit  20  is connected to the diffuser  18 . 
     A first end of a moisturized oxygen supply conduit  24  is connected to the oxygen outlet  10  while an opposed second end of the moisturized oxygen supply conduit  24  is connected to an oxygen dispensing device or apparatus, such as a cannula  26 . The cannula  26  has a pair of prongs  28  that are generally positioned in the nostrils of the patient to supply the moisturized oxygen to the patient. A conventional water trap  30  is positioned in the moisturized oxygen supply conduit  24 , between the oxygen outlet  10  and the cannula  26 , to remove any liquid conveyed along with the supplied and moisturized oxygen to the patient. 
     The important aspect concerning the engagement between the removable cover  4  and the humidifier base  6  is that those two components achieve a substantially gas and water tight seal is therebetween. A conventional oxygen supply system supplies a gas which has an oxygen content of between 93 percent to 95 percent with the balance of the supplied gas being nitrogen and other elements commonly found within air. The humidifier base  6  is typically sized to hold between 100 and 350 cc of liquid  22  to facilitate adding a sufficient amount of humidity to the oxygen being supplied, via the bubble humidifier  2 , to the patient. 
     As can be seen in FIGS. 6-10, the diffuser  18  generally comprises an exterior diffuser housing  32  which has an open first end which is sized and shaped to receive or mate with a remote end of the humidifier conduit  20  conveying the supply of oxygen to the diffuser  18  from the oxygen inlet  8 . The remote end of the diffuser housing  32  generally tapers or flares outwardly and is closed or covered by a generally planar end wall or cap  36 . The flared end cap  36  and the diffuser  18  may be formed separately from one another or are preferably integral with one another and together define a plurality of peripheral discharge passages  38 , e.g., eight discharge passages formed therein. Each one of the discharge passages  38  is equally spaced about the periphery of the diffuser  18 , e.g., located at an angle of 45° angle with respect to a longitudinal axis LD defined by the diffuser housing  32 . Due to this arrangement, as the oxygen to be moisturized flows along the longitudinal axis LD of the diffuser housing  32 , the oxygen impacts against the end cap  36  of the diffuser  18  and is forced and emitted out through one of the discharge passages  38  substantially at a right angle to the longitudinal axis L defined by the bubble humidifier  2 . The longitudinal axis LD defined by the diffuser housing  32  is substantially coincident with the longitudinal axis L defined by the bubble humidifier  2 . The oxygen emitted out through the discharge passages  38  has a tendency to form oxygen bubbles which are directed at and generally impact against the inner side wall of the humidifier base  6 . The oxygen bubbles, emitted out through the discharge passages  38 , tend to disperse within the liquid  22  as the oxygen bubbles permeate or filter up through the liquid  22  contained within the humidifier base  6  of the bubble humidifier  2 . 
     The relative high velocity of the oxygen bubbles, emitted out through the discharge passages, is reduced and partially absorbed as the oxygen flows through the liquid  22  toward the side wall of the humidifier base  6 . The velocity reduction and energy absorption by the liquid  22  contained within the humidifier base  6  as well as the humidifier base side wall, minimizes the amount of liquid  22  which has a tendency to be splashed or sprayed into the inlet of the moisturized oxygen supply conduit as the moisturized oxygen bubbles permeate upward through the liquid  22  and break the liquid surface. 
     With reference now to FIGS. 3 through 5, a detailed description concerning the pressure relief device  12  for use with the improved bubble humidifier  2  of the present invention will now be provided. As can be seen in these drawings, the pressure relief device  12  generally comprises a pressure relief housing  40  which has a relief port  42  formed in a base  58  of the pressure relief housing  40  which communicates directly with an interior compartment of the bubble diffuser  2 . A movable slug  44  is accommodated within the pressure relief housing  40  and the slug  44  is axially movable along a longitudinal axis LP defined by the pressure relief housing  40 . A downwardly facing surface of the slug  44  accommodates a conical shaped valve element  46  and the valve element  46  is sized and shaped to sealingly engage with the relief port  42  provided in the base  58  of the pressure relief housing  40 . Due to the weight of the slug  44 , e.g. about 8 grams or 0.285 ounces, the valve element  46  normally provides a gas tight seal with the relief port  42  provided in the base  58  of the pressure relief housing  40  to prevent the flow of any oxygen or liquid therethrough. 
     An inwardly facing surface  48  of the pressure relief housing  40  can be provided with a first guidance member  50 , such as an elongate rib which extends substantially along the longitudinal length of the pressure relief housing  40  while a complimentary guidance member  52 , e.g., a mating slot, is provided along a side wall  53  of the slug  44 . The elongate rib and the mating slot engage with one another to facilitate axial sliding movement of the slug  44  along the longitudinal axis LP of the pressure relief housing  40  while preventing rotation or misalignment of the slug  44  within the pressure relief housing  40 . This guidance mechanism  50 ,  52  also facilitates reseating of the valve element  46  with or over the relief port  42  should the slug  44  be biased away from engagement with the relief port  42  due to the generation of excess pressure within the bubble humidifier  2 , and a further detailed description concerning such relief will follow below. 
     The diameter of the slug  44  is slightly smaller in size than an internal diameter of the pressure relief housing  40  so that, in the event that the valve element  46  of the slug  44  is biased out of engagement with the relief port  42  of the pressure relief housing  40 , the oxygen will be allowed to pass between the exterior surface of the slug  44  and the interior surface of the pressure relief housing  40  and exit via an exhaust port  54  formed in the pressure relief housing  40 . The exhaust port  54  of the pressure relief device  12  is designed to generate a “whistling” sound, when a gas such as oxygen is exhausted therethrough, to indicate that the pressure relief device  12  is operating. It is to be appreciated that when the pressure relief device  12  is operational, this indicates to the medical personnel that a kink or some sort of blockage or occlusion is contained somewhere along the moisturized oxygen supply conduit  24 . When a medical personnel detects a whistling sound emitted by the pressure relief device  12 , the medical personnel will carefully examine the moisturized oxygen supply conduit  24  and remove any kink contained therein or remove any occlusion or blockage within the moisturized oxygen supply conduit  24  so that a continuous and uninterrupted supply of humidified oxygen is supplied to the patient. 
     Once the kink, occlusion or blockage is removed from the moisturized oxygen supply conduit  24 , the pressure inside the bubble humidifier  2  will decrease back to a normal operating pressure, e.g., between about 1-3 psi, and the slug  44  will have a tendency to be gradually lowered, by gravity within a few seconds or so, so that the valve element  46  again reseats and seals the relief port  42  of the pressure relief device  12 . To ensure that the valve element  46  properly reseats itself each time over the relief port  42  the pressure relief device  12  is activated, the valve element  46  is provided with an inclined conical surface  56  which forms an angle of about 15° with the longitudinal axis LP of the pressure relief device  12 . In addition, the valve element  46  has axial length of about 0.167 of an inch and a maximum diameter of about 0.145 of an inch, where the valve element  46  joins with the slug  44 . The slug  44  preferably has a diameter of 0.464+/−0.001 of an inch and a height of about 0.34 of an inch. The relief port  42 , provided in a base  58  of the pressuring relief device  12 , has a diameter of about 0.062 of an inch while the pressure relief housing  40  has an axial length of about 0.49 of an inch. 
     To facilitate proper reseating of the slug  44  within the relief port  42  provided in the base  58  of the pressure relief device  12 , at least one or a pair of opposed side exhaust ports  60  is/are provided in the side wall of the pressure relief housing  40 . These side exhaust ports  60  have a diameter of about 0.10 of an inch and are both generally located in the side wall of the pressure relief device  12  at a position so as to communicate with and be covered by a side wall of the slug  44  when the slug  44  in its lowermost position with the valve element  46  sealing engaging with the relief port  42 . In the event that the pressure within the bubble humidifier  2  becomes excessive, e.g., in excess of 3 psi for example, the slug  44  will be biased or moved axially away from the base  58  of the pressure relief device  12  whereby the valve element  46  disengages from the relief port  42  provided in the base  58  of the pressure relief device  12 . Once this occurs, the side exhaust ports  60  directly communicate with the oxygen entering into the pressure relief device  12 , via the relief port  42 , and some of this oxygen can be vented through the side exhaust ports  60  directly to the atmosphere while a remainder of the oxygen is vented through the exhaust port  54  and generates the “whistling” sound. The exhaust side ports  60  also facilitate proper reseating of the valve element  46  of the slug  44  with the relief port  42 , as soon as the medical personnel removes the kink, occlusion or other blockage contained in the moisturized oxygen supply conduit, since atmospheric air can enter through the side exhaust ports  60 . The side exhaust ports  60  thus allow the pressure of the pressure relief device  12  to be quickly equalized and this pressure equalization facilitates proper seating of the valve element  46  with the relief port  42 . 
     A top wall  62  of the pressure relief device  12  is provided with a stop  64  which is located to abut against a rear surface  66  of the slug  44  when the slug  44  is moved to its fully open position. The stop  64  is a generally cylindrical member which is coincident with the longitudinal axis LP of the pressure relief device  12 . 
     The slug  44  is generally designed to relieve the pressure contained within the bubble humidifier  2  once the pressure contained therein is between 3 and 6 psi, for example. The inventors have discovered that conventional pressure relief valves for bubble humidifiers do not operate adequately at higher oxygen flow rates, i.e., oxygen flow rates of between about 6 to about 15 liters per minute or possibly higher. The relief port  42  provided in the base  58  of the pressure relief device  12  is only operational when excessive pressure is generated within the internal compartment of the bubble humidifier  2  and the improved the pressure relieve device  12  facilitates more accurate and reliable reseating of the valve element  46  with the relief port  42 . 
     Since certain changes may be made in the above described improved bubble humidifier, diffuser and the pressure relief device, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention.