Manufacture of humidifier container and mold assembly therefor

Abstract: A hermetically sealed unitary liquid container of a thermoplastic material suitable for use in inhalation therapy is disclosed. The humidifier container comprises a body portion defined by an upstanding walled chamber having a bottom, a gas inlet duct unitary with the container body portion and defining a sealed gas inlet, and a sealed humidified gas outlet duct, both unitary with the container body portion. The container body portion constitutes a liquid reservoir and contains a predetermined amount of an aqueous aseptic or sterile aqueous liquid for humidifying a breathable gas. The gas inlet duct extends alongside the walled chamber, and has upper and lower end portions which are respectively situated above the container body portion and below usable liquid level in the container. The gas outlet duct communicates with the walled chamber above the usable liquid level. The gas inlet duct communicates with a gas diffuser defined by the container wall above the container bottom. The gas diffuser causes gas bubbles entering the liquid to rise through the liquid away from the container wall. The sealed gas inlet and the sealed gas outlet are provided with removable closures that can be broken off or twisted off. Relatively movable mold parts, as used for blow molding of the container, which is filled with liquid as it is molded, have grooves complementary to channels formed in the container.

Description: Technical Field of the Invention The present invention is generally related to the art of inhalation therapy. In particular, the present invention is directed to manufacture of a humidifier container suitable for use in inhalation therapy, and to a mold assembly useful for such manufacture. Still more particularly, the present invention is directed to manufacture of a humidifier container of the gas-bubbler type, hermetically sealed and containing an aseptic or sterile aqueous liquid, typically sterile water. Background of the Invention Inhalation therapy is the art of treating a patient with a breathable gas (such as air, oxygen, oxygen-enriched air) with moisture added thereto. Inhalation therapy devices include gas-bubbler devices and nebulizers for that purpose. The moisture can be provided by bubbling the breathable gas through a body of water or by atomizing or nebulizing water particles and thereafter combining such water particles with the breathable gas. Either method results in humidification of the breathable gas. It is known to blow mold hermetically sealed liquid containers of the gas-bubbler type, containing aseptic or sterile aqueous liquids, typically sterile water, for use in inhalation therapy. For example, each of U.S. Patent No. Re. 27,155 to Hansen and U.S. Patent No. 4,176,153 to Weiler et al. disclose an apparatus for making such a container. Each of U.S. Patent No. 3,807,713 to Cornett et al.; No. 3,903,216 to Allan et al.; and No. 4,187,951 to Cambio discloses a container of this general type. U.S. Pat. No. 4,217,328 to Cambio discloses the method of making the container described in the aforementioned U.S. Patent No. 4,187,951 to Cambio. Conventional gas-bubbler type humidifier containers typically include at the bottom thereof a gas-diffuser device for passing the breathable gas through the liquid contained therein. One problem with conventional humidifier containers of the gas-bubbler type is that an audible bubbling sound can be heard as the gas passes through the liquid in the container. To many an inhalation therapy patient such a bubbling sound is unpleasant and can even be disturbing. Also, in conventional humidifier containers bubbles tend to stick to the container wall and tend to grow in size undesirably before rising through the liquid. Such large gas bubbles not only tend to erupt more violently when breaking the liquid surface than small gas bubbles, but are known to be less efficient for gas humidification purposes. Summary of the Invention The present invention is directed to a humidifier container of the gas-bubbler type which is suitable for use in inhalation therapy and is relatively silent in operation. The humidifier container of the present invention is blow-molded as a unitary structure. It comprises: (a) a body portion, which defines a chamber having top, side, and bottom walls; (b) a gas inlet duct which is unitary with a side wall of the chamber and extends in a generally vertical direction; and (c) a manifold which extends from the gas inlet duct and communicates with plural gas apertures in a lower portion of the chamber, characterised in that said manifold is U-shaped and includes; (1) a first manifold end portion, which extends from and communicates with the gas inlet duct and is unitary with a side wall of the chamber; (2) a second manifold end portion, which is unitary with a side wall of the chamber and spaced from the first manifold end portion; (3) a gas conducting duct, which is unitary with a wall of the chamber and communicates with the first and second manifold end portions; (4) a first gas diffuser, which comprises plural gas apertures opening between the first manifold end portion and a lower portion of the chamber; and (5) a second gas diffuser, which comprises plural gas apertures opening between the second manifold end portion and a lower portion of the chamber. Brief Description of the Drawings Figure 1 is an elevational view of a humidifier container of the present invention; Figure 2 is a fragmentary view similar to Figure 1 but partially cut away and on an enlarged scale; Figure 3 is a fragmentary view taken from the right side of the embodiment shown in Figure 1. Figure 4 is a partial fragmentary and exploded side view, showing the upper portion of the humidifier container with portions cut away to show interior detail; Figure 5 is a partial elevational view of a section of a signal coupling threadedly engageable with the humidifier container of the present invention, shown on an enlarged scale relative to Figures 1-4; Figure 6 is a sectional view taken along plane 6-6 in Figure 5; Figure 7 is a fragmentary vertical sectional view of an upper portion of the humidifier container of the present invention within the forming mold thereof; Figure 8 is a fragmentary vertical sectional view of an upper portion of the humidifier container of the present invention within the respective forming molds thereof; Figure 9A is a fragmentary inclined sectional view, showing fragmentary portions of the respective forming molds used to form the container shown in Figure 1; and Figure 9B is a fragmentary inclined sectional view, similar to Figure 9A, but with the container omitted from the forming molds. Detailed Description of Preferred Embodiments While the present invention is susceptible to embodiment in various forms, there is shown in the drawings and hereinafter described in detail a presently preferred embodiment of the invention. The present disclosure is to be considered as an exemplification of the invention without limitation to the specific embodiments illustrated. Referring initially to Figures 1 to 3, a humidifier container or bottle 220 embodying the principles of the present invention is shown. Container 220 is suitable for use in combination with conventional inhalation therapy apparatus (not shown). Container 220 can be constructed by molding a suitable thermoplastic material such as polyethylene, polypropylene, or the like, and contains an aseptic or sterile aqueous liquid, such as water. Such a container can be formed as described in U.S. Pat. No. 4,176,153 to Weiler et al. That is, container 220 is formed from a molten tube of thermoplastic material, typically called parison, which is formed to the desired shape, then filled with the desired liquid and thereafter sealed. The forming, filling and sealing steps will be discussed in somewhat greater detail below in connection with discussion of Figures 7 and 8. Liquid container 220 comprises a body portion 222 defining an upstanding walled chamber 224 and having a bottom or base joined to a sidewall, a gas inlet duct 228 that terminates at the upper end thereof in a sealed gas inlet, and a sealed humidified gas outlet duct 232. The walled chamber 224 constitutes a reservoir for aqueous liquid and contains a predetermined amount thereof. The gas inlet duct 228 extends alongside the walled chamber 224 and is joined with the body portion 222 via webbings that are unitary with body portion 222 as well as inlet duct 228. At its upper end, gas inlet duct 228 terminates in an externally threaded male inlet coupling 238 for attachment to a suitable breathable gas source when the container is in use. Inlet coupling 238, in turn, defines gas inlet 230 that is occluded by removable tab 200 joined to inlet coupling 238 by a frangible web that is unitary with tab 200, as well as inlet coupling 238, and that surrounds gas inlet 230. When container 220 is readied for use, gas inlet 230 is opened by breaking or twisting off tab 200. Such action exposes gas inlet 230 without the need to drive a spike or cannula into container 220. As a result, the likelihood of introducing particulate matter or contamination into the container is substantially reduced. To couple container 220 to a breathable gas source, inlet coupling 238 is provided with appropriate external threads adapted to receive a cap-like, threaded female coupling. Inlet coupling 238 is situated above the body portion of container 220. Gas outlet duct 232 is also situated above the usable liquid level in container 220 and usually also above the body portion of container 220. Duct 232 communicates with chamber 224 and is occluded by a removable closure associated with tab 204. The distal end of gas outlet duct 232 is provided with external serrations 210 that are adapted to receive and retain thereon flexible tubing leading to the inhalation therapy patient. The removable closure for duct 232 is unitary therewith and is connected thereto by means of a frangible web that can be severed by breaking or twisting tab 204 when it is desired to open duct 232. Upper webbing 234 is unitary with container body portion 222, gas inlet coupling 238 and gas outlet duct 232. Tabs 200 and 204 can be hollow or solid, as desired. At its lower end, gas inlet duct 228 is connected to and communicates with a U-shaped manifold comprising first manifold end portion 283, which extends downwardly from and communicates with gas inlet duct 228 and is unitary with a side wall of chamber 224, a first gas diffuser, which is constituted by plural gas apertures 284 opening between first manifold end portion 283 and a lower end portion of chamber 224, gas conducting duct 285, which is unitary with the lower wall of chamber 224, second manifold end portion 286, which is unitary with a side wall of chamber 224 and spaced on an opposite side from first manifold end portion 283, and a second gas diffuser, which is constituted by plural gas apertures 287 opening between second manifold end portion 286 and a lower end portion of chamber 224. Gas conducting duct 285 communicates at its opposite ends respectively to first manifold end portion 283 and to second manifold end portion 286. Lower wall 284 of chamber 224 is arched, as shown in Figure 3, so as to elevate gas conducting duct 285 above lowermost extremities 288 of the side walls of chamber 224. Thus, when placed on a flat table (not shown) the humidifier container rests on such extremities 288, not on gas conducting duct 285. Provision of two gas diffusers allows a given quantity of a breathing gas to be humidified in the humidifier container at a faster rate. While container 220 can be connected to a breathable gas source in any convenient manner, preferably the connection of container 220 to a breathable gas source is effected by a threaded female coupling means 66 (Figure 5) embodying yet another feature of the present invention. More particularly, the threaded coupling means 66 provides an audible signal when back pressure in container 220 reaches a predetermined value. Signal coupling means 66 is a three-piece assembly which comprises a cup-shaped female connector 68 having unitary internal threads 70 which mate with threads 264 of gas inlet coupling 238, and an elongated nipple 76 that can be sealingly received within gas inlet 230. Nipple 76 is unitary with female connector 68, and defines therethrough a main gas passageway 74 for introducing breathable gas from a source (not shown) into gas inlet duct 228 via gas inlet 230. Nipple 76 is provided with a tapered, generally annularly-shaped sealing surface which provides a substantially gas-tight seal with the gas inlet 230 when disposed thereinto. Female connector 68 also includes an additional, unitary annular seal 78, substantially concentric with nipple 76, which provides a second seal around the gas inlet 230 when female connector 68 is threadedly engaged with gas inlet coupling 238. Opposite to nipple 76 on coupling means 66 is provided an upstanding protuberance 72 having a head portion 73 and a stem portion 75. Protuberance 72 defines an extension of main gas passageway 74. Head portion 73 is adapted to receive a suitable connection from a breathable gas source. Stem portion 75 additionally defines a signal gas passageway 80 between main gas passageway 74 and the outer periphery of stem portion 75, as well as a land portion 83 adjacent to and above gas passageway 80. The signal gas passageway 80 is disposed lateral to the main gas passageway 74, as shown in Figures 5 and 6. Land 83 may be flat, as shown, or slightly concave. A flexible, elastic sleeve 82 is positioned on the outer surface of stem portion 75 so as to occlude signal gas passageway 80 and lie contiguous with land 83. Sleeve 82 can be fabricated from natural latex rubber, silicone rubber, or like materials. When a pressure buildup is experienced within container 220 with coupling means 66 in place, gas pressure will force gas out through signal gas passageway 80, across land 83 and past sleeve 82 while generating an audible signal, e.g., a whistling sound. The radial compressive force exerted by elastic sleeve 82 determines the pressure at which the signal will be sounded. Recess 86 is provided in stem portion 75 to retain sleeve 82 in place. A small gap, as shown, may be provided between the upper edge of sleeve 82 and the upper edge of recess 86, in line with land 83. Also, a contoured neck portion 84 can be provided about the exit aperture of signal gas passageway 80 so as to enhance proper nesting of the flexible sleeve 82 and to guard against inadvertent or accidental blockage. A protective overcap 88 is provided for protuberance 72. Overcap 88 serves as a connector means to a breathable gas-metering device. Specifically, overcap 88 is provided with internal threads which mate with the gas-metering device. Overcap 88 surrounds protuberance 82 and is snap engageable therewith by means of flexible fingers or split ring 90 within the overcap. That portion of protuberance 72 which surrounds the inlet of the main gas passageway 74 is suitably radiused to provide a substantially gas-tight seal with the metering device when the overcap 88 is threadedly connected therewith. A unitary skirt 94 depends from overcap 88 and surrounds sleeve diaphragm 82 in a spaced relationship therefrom. Circumferentially-spaced radially-disposed wings 96 and 98 can be provided for coupling means 66 and for overcap 88, respectively, for torquing convenience. A gap or space is provided between skirt 94 and female connector 68 to provide an escape path or passageway for signal gas that is flowing out of container 220. Yet another feature of the present invention is the securement tabs 200 and 204 that are respectively unitary with inlet coupling 238 and gas outlet duct 232. These tabs facilitate the removal of each of the gas inlet and gas outlet closures employing a twist-off or break-off motion, or in any other convenient manner. A premature removal of these closures is obviously undesirable. Accordingly, in a preferred embodiment of this feature, the tab or handle 200 on inlet coupling 238 is made unitary with webbing 234 at the end portion of tab 200 that is opposite the gas inlet 230. Similarly, tab or handle 204 on gas outlet duct 232 is made unitary with webbing 206 at the distal portion of tab 204. Webbings 234 and 206 are frangible, so that the associated tabs can be readily separated therefrom by a bending or twisting motion. A method for making a container of the type described hereinabove will be discussed below with reference to the container 220 described above. The overall fabrication procedure is substantially the same as that described in U.S. Patent No. Re. 27,155 to Hansen and in U.S. Patent No. 2,425,294 to Weiler et al. The description of these two patents is incorporated herein by reference. More specifically, semi-molten hollow tube or parison 111 is extruded or otherwise positioned into relatively movable sectional mold assembly 109 (Figure 7) which includes first and second relatively movable mold parts 112 and 113 (Figure 8), each having the desired contour as determined by the shape of the container to be formed, filled, and sealed. Mandrels 114 and 116, vertically disposed and vertically movable within upper parison portion 111, are each positioned into mold assembly 109 as shown in Figure 7, and in a sealing relationship with the parison 111. A blowing gas such as air is then introduced into the parison 111 in two stages. Air is first introduced into mold assembly 109 via mandrel 114 and causes a side portion of the parison within the mold assembly to form gas inlet duct 228 and forms the apertures 284, 287 in gas manifold end portions 283, 286 by displacing semi-molten material trapped between mold parts 112 and 113, which are machined to have grooves complementary to apertures 284, 287 so as to blow holes forming apertures 284, 287. Next, the blowing gas is introduced into mold assembly 109 via mandrel 116 at a relatively higher pressure to form the remaining, main portion of the parison into walled chamber 224. The desired aseptic or sterile liquid is next introduced into chamber 224 via mandrel 116 while the chamber is vented through passageway 118 in mandrel 116. Thereafter mandrels 114 and 116 are raised above mold assembly 109. When mandrels 114 and 116 have been elevated, an upper mold assembly 119 comprising first and second upper relatively movable mold parts 120 and 122 are brought together (Figure 8) while engaging upper parison portion 111 therebetween, thereby hermetically sealing container 220 and at the same time forming that portion of container 220 which is above the second parting line PL2 (Figure 8). Webbing 234 and webbing 206 are formed from double layers of thermoplastic material brought together between mold parts 112 and 113 between mold parts 120 and 122. Upper webbing 234 provides a rigidifying connection between the container body portion 222, gas inlet coupling 238 and gas outlet duct 232, and is unitary therewith. A continuation of webbing 234 alongside body portion 222 and gas inlet duct 228 provides a unitary connection therebetween that also defines in part the hereinafter described gas apertures 284, 287 as well as their associated channels of communication between duct 228 and chamber 224. As mentioned above, first and second relatively movable mold parts 112 and 113 of relatively movable sectional mold assembly 109 are machined so as to have grooves complementary to apertures 284, 287 shown in Figure 2. In mold assembly 109, first mold part 112 has machined into an otherwise flat surface 264 of such part 112 (Figure 9B) a series of relatively deep grooves 265, 266, 267, and 268 alternated with relatively shallow grooves 269, 270, and 271. Each of the grooves 265 to 271 inclusive is machined so as to avoid internal corners. Also, second mold part 113 has machined into an otherwise flat surface 272 of such part 113 (Figure 9B) a series of relatively shallow grooves 273, 274, 275 and 276 alternated with relatively deep grooves 277, 278 and 279. Each of grooves 273 to 297 inclusive is machined so as to avoid internal corners. When mold assembly 109 is closed, surfaces 256 and 260 are spaced from each other, such that each of the relatively deep grooves in each such surface faces one of the relatively shallow grooves in the other surface. As the parison is pinched between mold parts 112 and 113, a thin webbing of the thermoplastic material is pinched therebetween. As gas inlet duct 228 is formed and pressurized in a mandrel (not shown), the pressure blows holes in the semi-soft thermoplastic trapped between mold parts 112 and 113 at locations between opposed pairs of relatively deep and relatively shallow grooves. Inasmuch as the relatively deep and relatively shallow grooves are offset from one another on each side of the mold parting line, the resultant channels 251 are likewise offset from one another. While the humidifier container embodying the present invention has been illustrated and described with reference to preferred embodiments, the present invention is not limited thereto. Alternatives, changes or modifications within the scope of this invention will become apparent to those skilled in the art upon reference to the claims.

Claims: A humidifier container blow-molded as a unitary structure comprising: (a) a body portion (222), which defines a chamber (224)having top, side, and bottom walls; (b) a gas inlet duct (228) which is unitary with a side wall of the chamber and extends in a generally vertical direction; and (c) a manifold which extends from the gas inlet duct and communicates with plural gas apertures in a lower portion of the chamber, characterised in that said manifold is U-shaped and includes; (1) a first manifold end portion (283), which extends from and communicates with the gas inlet duct (228) and is unitary with a side wall of the chamber (224); (2) a second manifold end portion (286), which is unitary with a side wall of the chamber and spaced from the first manifold end portion (283); (3) a gas conducting duct (285), which is unitary with a wall of the chamber and communicates with the first and second manifold end portions (283, 286); (4) a first gas diffuser, which comprises plural gas apertures (284) opening between the first manifold end portion (283) and a lower portion of the chamber (224); and (5) a second gas diffuser, which comprises plural gas apertures (287) opening between the second manifold end portion (286) and a lower portion of the chamber (224). The container in accordance with claim 1 wherein the gas conducting duct (285) is unitary with the bottom wall of the chamber (224).

Inventors: KOMENDOWSKI HENRY, WEILER GERHARD H, KOMENDOWSKI, HENRY, WEILER, GERHARD H.
Applicants: AUTOMATIC LIQUID PACKAGING, AUTOMATIC LIQUID PACKAGING, INC.
Application year: 1989
Main classification: B29C49
IPC codes: B29C49, B29C33, B01F15