Patent ID: 12214138

DETAILED DESCRIPTION

FIGS.2A and2Bdepict aspects of the use of a novel respiratory humidification device2000(which addresses many of the shortcomings of prior art respiratory humidification devices, including the prior art respiratory humidification device200described above) together with a ventilator or CPAP device990, and a hose assembly1000to provide a patient with humidified respiratory gases to breathe. As depicted, the ventilator or CPAP device990provides an inspiratory gas flow of respiratory gases to a gas inlet of the respiratory humidification device2000to be humidified with water988provided to the respiratory humidification device2000by the water source980.

The ventilator or CPAP device990may directly incorporate the heating component991by which the ventilator or CPAP device990provides heat to the respiratory humidification device2000to heat the water988and respiratory gases therein. In some embodiments, the heating component991may include an electrically heated hot plate atop which the respiratory humidification device2000may be placed to be heated in a manner akin to a pot placed atop an electric burner of a plate warmer or cooktop. As will be familiar to those skilled in the art, such provision of heat by the ventilator or CPAP device990to heat the water988and respiratory gases within the respiratory humidification device2000serves to both excite the molecules of the water988within the respiratory humidification device2000and increase the absorption capacity of the respiratory gases therein, thereby causing speedier and greater absorption of the water988into the respiratory gases.

As will shortly be explained in greater detail, within the respiratory humidification device2000, the incoming flow of respiratory gases received at the gas inlet from the ventilator or CPAP device990is split into a pair of gas flows that are each directed into a tube-like pathway that is partially defined by the surface of the water988heated with the heat energy provided by the heating component991. The tube-like configuration of each such pathway serves to keep its respective gas flow of respiratory gas in close contact with the surface of the water988to enhance the absorption of the water988into each gas flow. Each such tube-like pathway may follow a semi-circular path about a circular perimeter of the respiratory humidification device2000to elongate the path followed by each of the two gas flows to increase the amount of time that each gas flow is maintained in contact with the surface of the water988. Each such tube-like pathway may be shaped and/or sized to encourage the formation of a vortex of the gas within its respective gas flow. The axis of each such vortex may extend along its respective pathway and generally horizontal to the surface of the water998to further enhance the bringing of each of the two gas flows into contact with the surface of the water988to further enhance absorption. The two gas flows then rejoin at a gas outlet of the respiratory humidification device2000.

The now humidified respiratory gases are then conveyed from the gas outlet of the respiratory humidification device2000to a face mask, endotracheal tube or tracheostomy stoma940associated with a patient through an inspiratory hose assembly1002of a larger respiratory hose assembly1000. In some embodiments, other respiratory gases exhaled by the patient may be conveyed back to the ventilator or CPAP device990through an expiratory hose assembly1006of the respiratory hose assembly1000.

As depicted in greater detail inFIG.2B, the inspiratory gas flow of humidified respiratory gases from the respiratory humidification device2000may be monitored by a flow sensor910and/or a temperature sensor930of a sensor harness902. Cabling920of the sensor harness902may convey electrical and/or optical signals indicative of a detected rate of gas flow and/or of a detected temperature back to the ventilator or CPAP device990. The flow sensor910may be positioned at a fitting1100by which the inspiratory hose assembly1002may be coupled to the gas outlet of the respiratory humidification device2000to receive the humidified respiratory gases therefrom. In contrast, the temperature sensor930may be positioned at a fitting1300by which the other end of the inspiratory hose assembly1002may be coupled to the face mask, endotracheal tube or tracheostomy stoma940of the patient through a Y-fitting1400to provide the respiratory gases conveyed through the hose1200of the inspiratory hose assembly1002thereto.

In embodiments in which the other respiratory gases exhaled by the patient are to be conveyed back to the ventilator or CPAP device990, a fitting1500may couple the expiratory hose assembly1006to the Y-fitting1400to receive such exhaled respiratory gases therefrom. Correspondingly, a fitting1700may couple the other end of the expiratory hose assembly1006to the ventilator or CPAP device990to provide the exhaled respiratory gases conveyed through the hose1600of the expiratory hose assembly1006thereto.

Each of the hose assemblies1002and1006may incorporate heating wires by which each of the hoses1200and1600, respectively, may be heated. As will be familiar to those skilled in the art, it may be deemed desirable to heat one or both of the hoses1200and1600to prevent the temperature of the respiratory gases conveyed therethrough from dropping low enough as to cause condensation within the hoses1200and1600, respectively. Such condensation within either of the hoses1200or1600may lead to pooling of water within one or both, which may block the flow of respiratory gases therethrough. Additionally, pooling of water within the hose1200of the inspiratory hose assembly1002may create a risk of inhalation of liquid water by the patient such that drowning of the patient may occur.

Referring to bothFIGS.2A and2B, in some embodiments, the ventilator or CPAP device990may use the flow rate and/or the temperature detected by the sensors910and/or930, respectively, as inputs to adjust the amount of heat provided by the heating component991, to adjust the flow of respiratory gases provided to the respiratory humidification device2000, and/or to adjust the degree to which the wires incorporated into the hoses1200and/or1600are heated. As will be readily recognized by those skilled in the art, while the heating of the hose1200may serve to prevent condensation from occurring therein, the fact that the hose1200is “downstream” of the gas outlet of the respiratory humidification device2000prevents any heating of the hose1200from in any way assisting in the absorption of the water998within the respiratory humidification device2000into the respiratory gases that are then provided to the patient. Thus, it is to be understood that it is the heat provided by the heating component991of the ventilator or CPAP device990to the respiratory humidification device2000that plays a role in such the absorption of the water988therein.

A fuller explanation of the incorporation of heating wires into the hoses1200and/or1600, as well as the use of those heating wires, may be found in each of U.S. Provisional Application 62/499,623 filed Jan. 30, 2017 by Martin E. Forrester, U.S. patent application Ser. No. 15/882,286 filed Jan. 29, 2018 by Martin E. Forrester, U.S. patent application Ser. No. 15/882,257 filed Jan. 29, 2018 by Martin E. Forrester, and U.S. patent application Ser. No. 15/882,313 filed Jan. 29, 2018 by Martin E. Forrester, all of which are incorporated herein by reference to the fullest extent that is (or may become) possible under U.S. patent law.

FIGS.3A through3Hdepict aspects of a simplified example embodiment of the novel respiratory humidification device2000. As depicted, the respiratory humidification device2000has a generally cylindrical shape largely defined by a generally upstanding outer wall2104rising from a relatively flat casing bottom2200by which the respiratory humidification device2000may be supported atop a heating component991of a ventilator, CPAP device or other medical device990to be heated thereby. Upper portions of the outer wall2104may bend inwardly to form at least a portion of a casing top2100of respiratory humidification device2000integrally with the upstanding portion of the outer wall2104. Such a circular shape of at least the casing bottom2200may be deemed desirable in response to the common practice of designing the heating component991of a ventilator, CPAP device or other medical device990to have a circular shape.

It should be noted that, while the casing bottom2200is depicted and described herein as having flat and circular shape, other embodiments of the respiratory humidification device2000are possible in which the casing bottom2200is of a different physical shape in response to physical features of the heating component991of a particular ventilator, CPAP device or other medical device990. More specifically, where the heating surface provided by a particular heating component991is not circular in shape (e.g., has an oval or rounded rectangular shape), the casing bottom2200may have a corresponding or matching non-circular shape. Alternatively or additionally, where the heating surface provided by a particular heating component991is not flat (e.g., is convex, concave or of some other more complex shape), the casing bottom2200may have a corresponding or matching non-flat shape to better provide thermally-conductive contact between the casing bottom2200and such a heating surface. Indeed, it is envisioned that different versions of the respiratory humidification device2000may be fabricated to accommodate differences in physical features of the heating components991of various particular ventilators, CPAP devices and/or other medical devices990that provide respiratory gases in need of being humidified.

Referring toFIGS.3A-D, the interior of the respiratory humidification device2000is divided by a generally upstanding and cylindrical separator wall2140into a central filling chamber2008and an annular humidification chamber2004that encircles the central filling chamber2008. The separator wall2140is nested within the outer wall2104, and may be concentric with the outer wall2104. The separator wall2140at least partially defines the central filling chamber2008, and cooperates with the outer wall2104to at least partially define the annular humidification chamber2004. The casing bottom2200defines a common bottom of both of the chambers2004and2008.

As can be most clearly seen inFIGS.3B and3D, water988is provided from a water source (e.g., the water source980) to the respiratory humidification device2000through a water inlet2180that opens into the central filling chamber2008. As will be explained in greater detail, a valve incorporating a pair of floats may control the rate at which the water988is allowed to enter into the central filling chamber2008through the water inlet2180to control the amount of the water988present within the respiratory humidification device2000.

As can be most clearly seen inFIGS.3A-Band3G, the two chambers2004and2008are not completely separated by the separator wall2140. Instead, a predetermined vertical space is left between the bottom edge of the separator wall2140and the casing bottom2200to allow the water988that enters into the central filling chamber2008to flow into the annular humidification chamber2004, as can be most clearly seen inFIGS.3B,3D and3F. Thus, the water988is caused to pool at the bottom of both chambers2004and2008, and in contact with the casing bottom2200. As can be most clearly seen inFIGS.3A-Dand3G, the intention is to maintain a predetermined water line of the water988within both chambers2004and2008of the respiratory humidification device2000that serves to complete the division of the chambers2004and2008from each other in a manner somewhat akin to a drain trap of a sink, where the water988is allowed to flow between the two chambers2004and2008, but gases are not.

A flow of dry respiratory gases from a ventilator, CPAP device or other medical device is provided to the respiratory humidification device2000through a gas inlet2120that opens into the annular humidification chamber2004. As can be most clearly seen inFIGS.3A,3E and3H, near the gas inlet2120, the incoming flow of respiratory gases is divided into a pair of semi-circular gas flows. One of the two semi-circular gas flows follows a semi-circular path2009A within the annular humidification chamber2004that proceeds half way around one side of the central filling chamber2008. The other of the two semi-circular gas flows follows a mirror image semi-circular path2009B within the annular humidification chamber2004that proceeds half way around the other side of the central filling chamber2008. As the two semi-circular gas flows proceed around their respective paths2009A and2009B, the respiratory gases of each semi-circular gas flow is urged into contact with the surface of the water at or near the water line within the annular humidification chamber2004to absorb molecules of the water988, and to thereby become humidified. Both paths2009A and2009B meet near a gas outlet2160located opposite the gas inlet2120. The now humidified and re-combined flow of respiratory gases leaves the respiratory humidification device2000through the gas outlet2160to be conveyed to a patient by an inspiratory hose assembly1002.

As the casing bottom2200is heated from underneath by a heating component991, the water988(which is in contact with the casing bottom2200) is caused to be heated largely by conduction of heat through the casing bottom2200. In turn, respiratory gases that flow over the surface of the water988may become heated by the water988. Those same respiratory gases may also be heated by contact with the outer wall2104as a result of its contact with the casing bottom2200, and depending on the material(s) from which the outer wall2104is fabricated.

As can be most clearly seen inFIGS.3A,3C-D and3G, the paths2009A and2009B may each extend through a portion of the annular humidification chamber2004in which an elongate tube-like pathway is defined by the outer wall2104(which, as previously discussed, may also form part of the casing top2100), the separator wall2140, and the surface of the water988that fills the bottom of the annular humidification chamber2004up to or in the vicinity of the predetermined water line. Again, the presence of the water988within the annular humidification chamber2004at or near the predetermined water line prevents entry of the respiratory gases underneath the bottom edge of the separator wall2140, and into or through the central filing chamber2008, such that the water surface acts in a manner very much akin to a floor of each of the elongate tube-like pathways that the water surface aids in defining. Such use of such elongate tube-like pathways serves to constrain the paths2009A and2009B to extend over and parallel to the surface of the water988, thereby tending to keep the semi-circular gas flows following each of the paths2009A and2009B in contact with the surface of the water988over a distance that has been found to be sufficient to ensure sufficient absorption of molecules of the water988into each of the two gas flows as to ensure that the respiratory gases leaving the respiratory humidification device2000are sufficiently humidified.

As can be most clearly seen inFIGS.3G and3H, each of these two tube-like pathways may be shaped and sized to induce the formation of a vortex along each of the paths2009A and2009B. Each such vortex may be caused to extend generally horizontally (i.e., parallel to the plane of the surface of the water988), and may serve to ensure that a greater portion of the respiratory gases within each of the two semi-circular gas flows is put into contact with the surface of the water988to thereby provide more opportunity for the absorption of the water988.

As the water988within the annular humidification chamber2004is absorbed into the two semi-circular flows of respiratory gases therethrough, the water988therein is replenished from the central filling chamber2008through the space between the bottom edge of the separator wall2140and the casing bottom2200. In turn, the water988within the central filling chamber2008is replenished through the water inlet2180. As will be explained in greater detail, the earlier-mentioned pair of floats within the central filling chamber2008serve to limit the amount of the water988that is allowed to flow in through the water inlet2180to what is needed to replenish the water within the respiratory humidification device2000to a degree sufficient to maintain the surfaces of the water988within both of the chambers2004and2008at or near the predetermined water line.

It should be noted that, while the respiratory humidification device2000is depicted and described herein as having a distinct gas inlet2120through which respiratory gases enter to be humidified, and a distinct gas outlet2160though which humidified respiratory gases leave the respiratory humidification device2000; in at least some embodiments, the gas inlet2120and the gas outlet2160may be physically identical, and at least the internal physical design of the respiratory humidification device2000(if not also the external physical design) may be sufficiently physically symmetrical between the portion that includes the gas inlet2120and the portion that includes the gas outlet2160, that respiratory gases may be made to flow through the respiratory humidification device2000in either direction between the gas inlet2120and the gas outlet2160without any change in the effectiveness of the humidification of those respiratory gases. Stated differently, in such embodiments, it may make no functional difference, whatsoever, whether the gas inlet2120and the gas outlet2160are used as has been described, or are used in a manner in which their roles are reversed such that respiratory gases flow through the respiratory humidification device2000in the opposite direction from what is described herein. This may be deemed a desirable feature as a form of “failsafe” against instances in which the respiratory humidification device2000is inadvertently connected “backwards” to a combination of the respiratory hose assembly1000, and a ventilator, CPAP device or other respiratory device990.

FIGS.4A through4Idepict aspects of a more detailed example embodiment of the respiratory humidification device2000. As best seen inFIGS.4A-B, again, the exterior of the respiratory humidification device2000is formed from a casing top2100(which may include the outer wall2104) and the casing bottom2200. In at least some embodiments, the casing bottom2200may be formed from any of a variety of metals and/or other materials capable of conducting heat applied to the casing bottom2200by a ventilator, CPAP device or other medical device990into both the annular humidification chamber2004and the central filling chamber2008. In contrast, the casing top2100may be formed from any of a variety of plastics and/or other materials capable of acting as thermal insulators to aid in keeping, within the respiratory humidification device2000, the heat that is conveyed into the chambers2004and2008of the respiratory humidification device2000through the thermally conductive casing bottom2200. Any of a variety of bonding, welding, and/or other techniques for coupling materials in a manner that forms a watertight seal may be used to join the casing top2100to the casing bottom2200about their peripheries.

In some embodiments, the respiratory humidification device2000may be intended to be discarded after being used for a predetermined period of time that may be selected to limit the degree to which bacteria and/or other microbial contaminants are allowed to take hold within the interior of the respiratory humidification device2000before it is discarded and replaced within another one. In such disposable embodiments, the casing top2100may be formed of a relatively inexpensive thermally insulating plastics material such as polystyrene, and the casing top2200may be formed of a relatively inexpensive thermally conductive metal such as aluminum.

As with the respiratory humidification device2000ofFIGS.3A-H, the respiratory humidification device2000ofFIGS.4A-Imay have a generally cylindrical shape with the outer wall2104of the casing top2100rising vertically with a cylindrical shape from the relatively flat casing bottom2200. Again, upper portions of the outer wall2104may bend inwardly to form at least a portion of the top of respiratory humidification device2000integrally with the upstanding portion of the outer wall2104, at least for the portions of the annular humidification chamber2004that extend between the gas inlet2120and the gas outlet2160. Again, such a circular shape of at least the casing bottom2200may be deemed desirable in response to the common practice of designing the heating components991of a ventilator, CPAP device or other medical device990to have a circular shape.

Turning more specifically toFIG.4C, in addition to the casing top2100and the casing bottom2200, embodiments of the respiratory humidification device2000may include a valve2800, a large float2600and a small float2700that may cooperate to perform the earlier-described function of limiting the amount of the water988that enters the respiratory humidification device2000through the water inlet2180. Alternatively or additionally, embodiments of the respiratory humidification device2000may include a pair of heat exchangers2400. As will be explained in greater detail, each of the pair of heat exchangers2400may be disposed along one of the paths2009A and2009B to enhance the heating of the respiratory gases flowing therealong. As also depicted inFIG.4C, in various embodiments, one or more of the depicted components may be formed as multiple parts that are formed separately and subsequently combined. Thus, as can be seen, each of the casing top2100, the large float2600, the small float2700and/or the valve2800may be so formed from multiple parts.

Turning more specifically toFIG.4D, again, the interior of the respiratory humidification device2000is divided into the central filling chamber2008and the annular humidification chamber2004by the separator wall2140. However, once again, and as best seen inFIGS.4E-H, the separator wall2140does not fully separate the two chambers2004and2008, and instead, a predetermined vertical space is left between the bottom edge of the separator wall2140and the casing bottom2200to allow the water988that enters into the central filling chamber2008to flow through that space and into the annular humidification chamber2004. As also depicted inFIG.4D, in embodiments in which the casing top2100is formed from more than one part, the upper-most surface of the casing top2100may have a valve guide aperture2108formed therethrough to receive a separate part of the casing top2100that carries and/or guides the movement of the valve2800, as well as of the floats2600and/or2700, as will be explained in greater detail.

Turning more specifically toFIGS.4D-F, again, a flow of dry respiratory gases from a ventilator, CPAP device or other medical device990are provided to the respiratory humidification device2000through the gas inlet2120that opens into the annular humidification chamber2004. Near the gas inlet2120, the incoming flow of respiratory gases is divided into a pair of semi-circular gas flows that each follow one of the paths2009A and2009B. As the two semi-circular gas flows proceed around their respective paths2009A and2009B, the respiratory gases of each are urged into contact with the surface of the water988at or near the water line within the annular humidification chamber2004to absorb water molecules thereof, and to thereby become humidified. The two semi-circular gas flows meet and rejoin near the gas outlet2160located opposite the gas inlet2120, and the now humidified and re-combined flow of respiratory gases leaves the respiratory humidification device2000through the gas outlet2160to be conveyed to a patient.

FIG.4Dprovides a view (from underneath the open bottom of the casing top2100) of the manner in which each of the paths2009A and2009B extend in a semi-circular manner around the separator wall2140, and thereby, extend around the central filling chamber2008. Each ofFIGS.4E-Fprovide a sectional view (one in perspective, the other in elevation) in which half of the casing top2100is cut away (but, in which the casing bottom2200is not cut away) to reveal portions of the paths2009A (which loops in a semi-circle out of and back into the page around the central filling chamber2008) and2009B (which extends around behind the central filling chamber2008).FIG.4Emore clearly depicts the separate water lines of the water within each of the chambers2004and2008. As shown, it may be deemed desirable for the water levels within each of the chambers2004and2008to remain the same or at least relatively similar.

Turning more specifically toFIGS.4G-H, again, the paths2009A and2009B may each extend through a portion of the annular humidification chamber2004in which an elongate tube-like pathway is defined by the outer wall2104(which, again, may also bend inwards to define at least part of the top surface of the casing top2100), the separator wall2140, and the water that fills the bottom of the annular humidification chamber2004up to or in the vicinity of the predetermined water line. Again, such use of such elongate tube-like pathways serves to constrain the paths2009A and2009B to extend over and parallel to the surface of the water988, thereby tending to keep the two semi-circular gas flows following each of the paths2009A and2009B in contact with the surface of the water988over an elongated distance that has been found to be sufficient to ensure sufficient absorption of molecules of the water988into the respiratory gases.

Along withFIG.4I, each ofFIGS.4G-Halso depicts the positioning of one each of the heat exchangers2400within each of these elongated tube-like pathways defined by the outer wall2104, the separator wall2140and the surface of the water988. As depicted, each of the heat exchangers2400may be suspended within its respective tube-like pathway so as to extend partially into the water988therein, but not deep enough to make contact with the casing bottom2200. As previously discussed, the water within both of the chambers2004and2008is heated by a ventilator, CPAP device or other medical device through the thermally conductive casing bottom2200to excite the molecules of the water988therein. Additionally, such heating of the water988also serves to indirectly heat the respiratory gases that flow through the respiratory humidification device2000to thereby cause increase the absorption capacity of those respiratory gases.

Each of the heat exchangers2400may be formed from a sheet of metal or other thermally conductive material to absorb some of the heat in the water988within the annular humidification chamber2004and radiate it into the respiratory gases flowing along respective ones of the paths2009A and2009B.FIG.4Imost clearly depicts the further splitting of the semi-circular gas flows along each of the paths2009A and2009B to cause flowing of those gases along both sides of each of the heat exchangers2400, thereby enabling each heat exchanger2400to radiate heat into more of the flow of respiratory gases along each path2009A and2009B than may be reached by heat rising (or otherwise being imparted to these gas flows) from the surface of the water988. As additionally depicted inFIG.4I, each of the heat exchangers2400may be given a curved shape to better follow respective ones of the paths2009A and2009B.

Alternatively or additionally, in various embodiments, each of the heat exchangers2400may be shaped, sized and/or positioned within respective ones of the tube-like pathways followed by respective ones of the paths2009A and2009B to aid in inducing and/or shaping a horizontally extending vortex of the respiratory gases flowing therethrough, as previously discussed.

FIGS.5A through5Fdepict aspects of the cooperation among the valve2800, and the two floats2600and2700(originally introduced inFIG.4Cfor the more detailed embodiment ofFIGS.4A-I, but which may also be included in the simplified embodiment ofFIGS.3A-H) to control the amount of water that enters the respiratory humidification device2000, and thereby control the level of the water988within the chambers2004and2008. As previously discussed, as the water988within the annular humidification chamber2004is absorbed into the two semi-circular flows of respiratory gases along the paths2009A and2009B therethrough, the water988therein is replenished from the central filling chamber2008through the space between the bottom most edge of the separator wall2140and the casing bottom2200. In turn, the water988within the central filling chamber2008is replenished through the water inlet2180.

However, although such an inflow of water into the respiratory humidification device2000is necessary to its function of humidifying respiratory gases, such an inflow of water does come with risks. By way of example, if too much water enters the respiratory humidification device2000, the water988may be output through the gas outlet2160and sent onward to a patient who may be harmed by the inhalation of liquid water. To prevent this, each of the floats2600and2700may be positioned within the central filling chamber2008to float on the surface of the water988therein, independently of each other. Also, each of the floats2600and2700may be guided therein for vertical movement by which either or both of the floats2600and2700may be caused to engage the valve2800to cause the valve2800to close the inlet2180in response to the level of the water988within the central filling chamber2008rising above a predetermined threshold maximum level. As will be explained in greater detail, each of the two floats2600and2700may interact with the valve2800in a manner that is entirely independent of the other such that the two floats2600and2700are redundant to each other such that one will still function to operate the valve2800if the other fails.

As best seen inFIGS.5A-C, such guidance for such vertical movement may be provided by a valve guide2181that forms the part of the casing top2100and is fabricated to be mounted within the earlier-discussed guide aperture2108. As depicted, the valve2800is carried within the valve guide2181in a manner that supports the valve2800for vertical movement therein. Also extending into the valve guide2181from underneath the valve guide2181is a float top2701that defines an upper most surface of an upper portion of the small float2700. As also depicted, the small float and a lower portion of the valve guide2181are both surrounded by the large float2700.

As best seen inFIGS.5D and5F, the positioning of the upper portion of the small float2700within the valve guide2181positions the float top2701to engage a valve bottom2802that defines the lower most surface of the valve2800to lift the valve2800upward within the valve guide2181in response to a rising water level within the central filling chamber2008. If the valve2800is so lifted sufficiently high within the valve guide2181from underneath by the small float2700, then a valve top2801that defines the upper most surface of the valve2800may be pressed against an inlet tip2182of the water inlet2180, thereby closing the water inlet2180so as to not allow more of the water988to enter the respiratory humidification device2000.

Correspondingly, as best seen inFIGS.5D-E, the positioning of the upper portion of the large float2600to surround the valve guide2181positions a pair of float tops2601that define upwardly facing surfaces of the large float2700to engage corresponding valve tabs2888that protrude through corresponding tab guides2188formed through the wall of the valve guide2181to lift the valve2800upward within the valve guide2181in response to a rising level of the water988within the central filling chamber2008. As with lifting of the valve2800by the small float2700, if the valve2800is lifted sufficiently high within the valve guide2181by engagement with the valve tabs2888by the float tops2601of the large float2600, then the valve top2801may be pressed against the inlet tip2182of the water inlet2180, thereby closing the water inlet2180.

Each ofFIGS.6A and6Bdepicts details of alternate embodiments of the respiratory humidification device2000. Turning toFIG.6A, it may be that differences in pressure between the chambers2004and2008may cause unpredictable raising or lowering of the water level within the annular humidification chamber2004such that water therein may be output through the gas outlet2160while the water level within the central filling chamber2008remains low enough that operation of the valve2800to close the water inlet2180is not triggered by either of the floats2600or2700. As an approach to address such a possibility, in one alternate embodiment, at least one separator notch2144may be formed along the bottom edge of the separator wall2140to provide a pathway above what is intended to be the water line to allow gas to be exchanged between the two chambers2004and2008. As depicted, the positioning of each such separator notch2144may be directly below (or nearly directly below) one of the gas inlet2120or the gas outlet2160.

From various tests, it appears that such positioning of one or two of such separator notches2144in the vicinity of where the flow of respiratory gases is either divided into the two semi-circular gas flows that proceed along the paths2009A and2009B or in the vicinity of where they are recombined causes negligible disruption to the flow of respiratory gases, at least in comparison to positioning any of such separator notches along either of the paths2009A or2009B.

Turning toFIG.6B, in another alternate embodiment of the respiratory humidification device2000, the large float2600may be shaped and sized to at least partially serve the function of the separator wall2140in defining a pair of elongate tube-like semicircular pathways in lieu of having the separator wall2140to do so. Additionally, the direction of the flow of respiratory gases in the vicinity of where they are split into the two semi-circular gas flows and in the vicinity of where the two semi-circular gas flows recombine may be controlled by the addition of an inlet guide2121just beneath the gas inlet2120and a corresponding outlet guide2161just beneath gas outlet2160.

Although the invention has been described in a preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example, and that numerous changes in the details of construction and the manner of manufacture may be resorted to without departing from the spirit and scope of the invention. It is intended to protect whatever features of patentable novelty exist in the invention disclosed.