Patent Publication Number: US-10773868-B2

Title: Container closure having means for introducing an additive into a liquid in the container

Description:
The present invention relates to a closure device, for use with a container such as a beverage container, which can fire a pressurised additive liquid into a liquid in the container by operation of the closure device. The invention also relates to a container including such a closure device and to a method of introducing an additive liquid by means of operating such a closure device. 
     In a number of applications, such as mixtures of different liquids, it may be necessary to release and mix an additive liquid into another liquid shortly before the liquid mixture is used. It may not be possible or desirable to store the liquids in a premixed form, as they may react undesirably with each other when stored as the mixture for a period of time. An example of this may be two component pharmaceuticals which have a longer shelf life when unmixed than they do when mixed. However, it can also apply to other liquids or to mixtures of liquids and gases, such as water, alcoholic beverages, other beverages, and other solvents or solutions. The term “beverage” when used in this specification includes any liquid, whether or not provided for drinking purposes, which may be mixed with an additive liquid, and is not limited to potable beverages. 
     A closure device for use with a beverage container which can release an additive liquid into the beverage by operation of the closure device is known from the prior art. International Patent Application WO2007/129116 discloses a closure device comprising a cap member defining a fluid chamber and a plug member which sealingly engages an aperture in the bottom of the fluid chamber. The cap member is raised relative to the plug member by unscrewing the cap member, from a closed position in which the plug member closes the bottom aperture to an open position in which the plug member is partially withdrawn from the bottom aperture to allow pressurised fluid to flow from the fluid chamber through a nozzle passage in the plug member to the beverage in the beverage container. 
     The known device has the disadvantage that it is relatively complex to manufacture, requiring separate housing and cap members, both of which extend outside the neck of the container. The closure has a larger diameter than conventional closures, since it must accommodate a housing flange between the external thread of the bottle neck and the internal thread of the outer cap wall. The closure requires the threaded connection between the cap and the housing flange to turn first, so that the cap member is raised relative to the plug member causing the additive to be fired from the pressurised fluid chamber, before the threaded connection between the housing flange and the bottle neck. If the threaded connection between the cap and the housing flange is too stiff, the threaded connection between the housing flange and the bottle neck may turn first, so that the closure device is removed from the bottle without firing. 
     It is an object of the present invention to overcome one or more disadvantages of the prior art. 
     Closure Device 
     According to a first aspect of the present invention there is provided a closure device for use with a container having a main liquid compartment and an opening with a container neck, the closure device comprising:
         a cap member having a side wall adapted to be secured to the opening of the container,   a fluid chamber fixed at its upper end to the cap member and having a bottom aperture at its lower end,   a housing at least partially surrounding the fluid chamber and having a flange member adapted to extend at least partially across the top of the container neck,   a plug member fixed to the housing and sealingly engageable in the bottom aperture of the fluid chamber,   wherein the plug member has a nozzle therein,   wherein the housing is adapted to move relative to the cap member between a first closed position of the closure device, in which the plug member seals the bottom aperture closed and the housing or cap member is engaged by a detent member provided to prevent movement of the housing away from the cap member, and a second armed position, in which the plug member continues to seal the bottom aperture closed and the flange member or detent member is deformed to a position in which the housing can no longer be engaged by the detent member.       

     Preferably the detent member is provided on the cap member or fluid chamber, and in the first closed position of the closure device the housing is engaged by the detent member. However the detent member may be provided on the housing so that the in the first closed position of the closure device the cap member or fluid chamber is engaged by the detent member. 
     In the first closed position of the closure device the housing may comprise an internal rib engaged by the detent member to prevent movement of the housing away from the cap member. In the second armed position of the closure device the detent member may be deformed to a position in which the internal rib can no longer be engaged by the detent member. 
     If the detent member is provided on the housing, in the first closed position of the closure device the cap member or fluid chamber may comprise an external rib engaged by the detent member to prevent movement of the housing away from the cap member. In the second armed position of the closure device the detent member may be deformed to a position in which the external rib can no longer be engaged by the detent member. 
     The side wall of the cap member may be threaded and may be adapted to engage with a thread or projection provided on the container neck. 
     The cap member may be a crown cap and may be adapted to engage with a flange provided on the container neck. 
     The cap member may be a threaded crown cap and may be adapted to engage with a thread provided on the container neck. 
     Collapsible Flange and Bridge Embodiments 
     In the first closed position of the closure device the flange member of the housing may be engaged by the detent member to prevent movement of the housing away from the cap member. In the second armed position of the closure device the flange member may be deformed to a position in which the flange member can no longer be engaged by the detent member. 
     Collapsible Flange Embodiment 
     In one preferred embodiment the flange member is adapted to extend across the top of the container neck and engage with a detent member provided on an inner surface of the threaded side wall of the cap member. In this embodiment the housing is adapted to move relative to the cap member between a first closed position of the closure device, in which the plug member seals the bottom aperture closed and the flange member is engaged by the detent member to prevent movement of the housing away from the cap member, and a second armed position, in which the plug member continues to seal the bottom aperture closed and the flange member is deformed to a position in which it can no longer be engaged by the detent member. 
     The flange member may include one or more plastically deformable portions which deform such that the outside diameter of the flange member in the deformed state when the closure device is in the armed position is less than the outside diameter of the flange member in the undeformed state when the closure device is in the closed position. 
     Bridge Embodiment 
     In another preferred embodiment the flange member is adapted to cantilever across all or part of the top of the container neck and is connected to the housing by a plurality of bridge portions of reduced thickness. The detent member is provided on an outer wall of the fluid chamber. In this embodiment the housing is adapted to move relative to the cap member between a first closed position of the closure device, in which the plug member seals the bottom aperture closed and the flange member is engaged by the detent member to prevent movement of the housing away from the cap member, and a second armed position, in which the plug member continues to seal the bottom aperture closed and the bridge portions are fractured so that the flange member is separated from the housing and so that the housing can no longer be engaged by the detent member. 
     Detachable Detent Embodiment 
     The housing may comprise an internal rib adapted to engage with the detent member provided on the cap member or fluid chamber. In the first closed position of the closure device the internal rib may be engaged by the detent member to prevent movement of the housing away from the cap member. In the second armed position of the closure device the detent member may be deformed to a position in which the internal rib can no longer be engaged by the detent member. 
     The housing may include an abutment member adapted to abut against the detent member. The detent member may be detachable by tearing. The detent member may be detachable by movement of the closure device from the first closed position to the second armed position, such as to cause the abutment member on the housing to tear the detent member from the cap member or fluid chamber. 
     The detent member may be discontinuous and may comprise a plurality of discrete detent portions. 
     The closure device may comprise corresponding detents on the housing and the fluid chamber to prevent the fluid chamber being removed completely from the housing. 
     All Embodiments 
     Preferably the fluid chamber is pressurised. 
     Preferably the fluid chamber contains a pressurised additive liquid and a propellant fluid. 
     The flange member can be deformed by securing the closure device to a container neck, such that the top of the container neck is urged against the flange member. 
     In the first position the closure device can be transported for subsequent fitting to a container. The detent and flange serve to prevent the housing and plug member from moving under the internal pressure of the fluid chamber, thereby maintaining the fluid camber in a sealed, closed state. 
     When the closure device is fitted to a container, the container neck is urged against the flange member to deform the flange member, so that the closure device is in the second armed position. The flange member itself may be held between the top of the container neck and the cap member, so the housing and plug member continue to be prevented from moving under the internal pressure of the fluid chamber, thereby maintaining the fluid camber in a sealed, closed state. Alternatively, or in addition, friction between the housing and the container neck may the housing and plug member from moving relative to the fluid chamber under the internal pressure of the fluid chamber, thereby maintaining the fluid camber in a sealed, closed state. 
     Preferably the housing is adapted to move relative to the cap member to a third firing position in which the plug member is arranged to provide a fluid communication path from the fluid chamber through the nozzle of the plug member and in which the flange member is not engaged by the detent member. 
     This allows an additive liquid in the fluid chamber to be ejected through the nozzle under pressure. 
     Preferably the fluid chamber is pressurised. The additive liquid is then urged through the nozzle under pressure into the container where it is mixed with the liquid or beverage in the container as a result of being ejected through the nozzle under pressure. 
     In a first arrangement of the plug member, the nozzle may be provided at the lower end of the plug member, opposite the fluid chamber. The plug member may include an internal nozzle passage extending axially upwards in the plug member from the nozzle. 
     The plug member may include a transverse internal passage extending to the lateral exterior surface of the plug member and in communication with the internal nozzle passage. 
     In the closed and armed positions the transverse internal passage may be closed by the bottom aperture of the fluid chamber. For example an upper seal may be provided between the plug member and the bottom aperture above the transverse internal passage. 
     In the firing position the upper seal may no longer seal between the plug member and the bottom aperture, such that the fluid chamber is in fluid communication with the transverse internal passage and the nozzle. A lower seal may be provided between the plug member and the bottom aperture below the transverse internal passage. 
     Alternatively the plug member may include a longitudinal internal passage extending to the upper exterior surface of the plug member and in communication with the internal nozzle passage. 
     In the closed and armed positions the longitudinal internal passage may be closed by a projecting plug fixed relative to the fluid chamber. 
     In the firing position the projecting plug may be spaced from the upper exterior surface of the plug member, such that the fluid chamber is in fluid communication with the longitudinal internal passage and the nozzle. 
     The plug member may include sealing means to provide a seal between the lateral external surface of the plug member and the aperture of the fluid chamber. The sealing means may be a coating of an elastomeric material, such as a soft plastic. The sealing means may form the upper and/or lower seals. 
     The housing may include an upper cylindrical portion adapted to fit inside a neck of the container. The housing may include a plurality of leg members extending from the upper cylindrical portion to the plug member. The leg members may be spaced from each other to allow fluid flow between the leg members. The leg members may be arranged to at least partially surround the fluid chamber so as to guide the fluid chamber while the fluid chamber moves from the closed position to the armed position and to the firing position. 
     In a second arrangement of the plug member, the plug member has an annular channel adapted to sealingly engage with the open end of a cylindrical wall portion of the tank, wherein the annular channel has at least one orifice which is arranged to be sealed from the interior volume of the tank when the annular channel is sealingly engaged with the open end of the cylindrical wall portion in the first closed position and second armed position of the closure device and which is in fluid communication with the interior volume of the tank when the annular channel is separated from the open end of the cylindrical wall portion in the third firing position of the closure device. 
     The open end of the cylindrical wall portion and the annular channel effectively form a plug and socket, which serve to seal the one or more orifices when the closure device is in the closed and armed positions, but open all the one or more orifices simultaneously when the tank is raised relative to the plug member and the closure device is in the firing position. 
     The annular channel may have a plurality of orifices which are arranged to be sealed from the interior volume of the tank when the annular channel is sealingly engaged with the open end of the cylindrical wall portion in the closed and armed positions of the closure device and which are in fluid communication with the interior volume of the tank when the annular channel is separated from the open end of the cylindrical wall portion in the firing position of the closure device. Preferably the orifices are arranged in an annular pattern. 
     If the closure assembly has a plurality of orifices, an additive liquid can be ejected in a “shower head” pattern, to improve distribution and mixing of the additive liquid within the beverage or other liquid in the container. 
     Preferably the plug member includes a stopper portion adapted to project inside the open end of the cylindrical wall portion of the tank in the closed and armed positions. Such a stopper portion comprises a secure and positive seal to the pressurised tank. 
     The plug member may include a seal in the annular channel adapted to seal between the plug member and an internal surface of the cylindrical wall portion in the closed and armed positions. Such a seal ensures that the tank cannot leak during storage of the closure device in its pressurised state, either before or after fitting to a container. 
     The plug member may include a seal in the annular channel adapted to seal between the plug member and an external surface of the cylindrical wall portion in the firing position. Such a seal ensures when the additive is fired under pressure from the tank it cannot pass upwards outside the tank between the neck of the container and the tank. 
     The fluid chamber may be a single moulded article. The fluid chamber may be moulded from PET or other suitable plastic material. 
     Preferably the cap wall is provided with internal threads adapted to engage with external threads on the neck of the container. 
     The fluid chamber may contain an additive liquid and a pressurised propellant gas. 
     The housing and the fluid chamber may be provided with mutually engaging detent means to prevent the separation of the cap member and the housing. This ensures that the housing is removed with the rest of the closure device when the cap member is unscrewed from the container neck. 
     The mutually engaging detent means may be provided on the exterior surface of the side wall of the fluid chamber and the internal surface of a cylindrical wall of the housing, for example in the form of circumferential ribs. 
     Alternatively the mutually engaging detent means may be provided on the exterior surface of a side wall of the bottom aperture of the fluid chamber and the internal surface of a corresponding cylindrical wall of the housing surrounding the side wall of the bottom aperture, for example in the form of circumferential ribs. 
     Container and Closure 
     According to a second aspect of the present invention there is provided a container having a container neck and an opening, wherein the container contains a liquid, and wherein a closure device according to the first aspect of the present invention is secured to the container neck to close the container. 
     Preferably the flange member is held between the top of the container neck and the cap member. Preferably the closure member is in the armed position. 
     Method of Firing 
     According to a third aspect of the present invention there is provided a method of introducing an additive liquid into a container, the method comprising:
         providing a closure device according to the first aspect of the invention,   introducing into the fluid chamber a liquid additive and a pressurised propellant,   while the closure device is in the first closed position placing the closure device on the neck of a container containing a liquid,   lowering the closure device onto the neck of the container such that the neck of the container contacts the flange member of the housing,   further lowering the cap member relative to the housing such that the flange member of the housing or detent member is deformed to a position in which the flange member or housing or cap member can no longer be engaged by the detent member and the closure device is in the second armed position, and   raising the closure device on the neck of the container such that the cap member and fluid chamber are raised relative to the plug member and the closure device is in a third firing position in which a fluid communication path is provided from the fluid chamber through the nozzle of the plug member.       

     During the step of lowering the cap member relative to the housing, the neck of the container may deform the flange member of the housing to a position in which the flange member or housing can no longer be engaged by the detent member. 
     Preferably the method includes the step of urging the additive liquid from the fluid chamber into the container under pressure of the pressurised propellant in the fluid chamber while the closure device is in the third firing position. 
     Preferably the method includes the step of mixing the additive liquid with the liquid in the container. 
     The liquid in the container may be a beverage or a chemical or pharmaceutical composition. The liquid may be of any viscosity, for example a gel. 
     The mixing step may be effected through ejection of the additive liquid through the nozzle at a sufficient velocity under pressure of the pressurised propellant in the fluid chamber. 
     Collapsible Flange Embodiment 
     In one preferred embodiment, before the deformation step the flange member extends across the top of the container neck and engages with a detent member provided on an inner surface of the threaded side wall of the cap member. 
     Preferably in the deformation step the flange member is deformed to a position in which it can no longer be engaged by the detent member. 
     Preferably in the deformation step one or more plastically deformable portions of the flange member are deformed such that the outside diameter of the flange member in after deformation is less than the outside diameter of the flange member before deformation. 
     Bridge Embodiment 
     In another preferred embodiment, before the deformation step the flange member extends in a cantilevered manner across all or part of the top of the container neck and is connected to the housing by a plurality of bridge portions of reduced thickness. 
     Preferably before the deformation step a portion of the flange member engages with a detent member provided on an outer wall of the fluid chamber. 
     Preferably in the deformation step the flange member is deformed by fracturing one or more bridge portions so that the flange member is separated from the housing, and so that the housing can no longer be engaged by the detent member. 
     In the deformation step the housing may be retained by the detent portion from moving with the flange member. 
     Detachable Detent Embodiment 
     In another preferred embodiment the detent member is provided on the cap member or fluid chamber, and during the further lowering of the cap member relative to the housing, the detent member is detached by tearing such that the housing can no longer be engaged by the detent member. 
     The housing may comprise an internal rib adapted to engage with the detent member provided on the cap member or fluid chamber. During the further lowering of the cap member relative to the housing, the detent member may be deformed to a position in which the internal rib can no longer be engaged by the detent member. 
     The housing may include an abutment member adapted to abut against the detent member. During the further lowering of the cap member relative to the housing, the detent member may be detached by movement of the cap member relative to the housing, such as to cause the abutment member on the housing to tear the detent member from the cap member or fluid chamber. 
     During the step of raising the closure device on the neck of the container such that the cap member and fluid chamber are raised relative to the plug member, corresponding detents provided on the housing and the fluid chamber may engage with each other to prevent the fluid chamber being removed completely from the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described, by way of example only, with reference to the drawings in which: 
         FIG. 1  shows a schematic cross-sectional view of a closure device according to an embodiment of the present invention; 
         FIG. 2  shows a schematic cross-sectional view of a closure device according to another embodiment of the present invention; 
         FIGS. 3A, 3B and 3C  show schematic cross-sectional views of a closure device according to another embodiment of the present invention; 
         FIGS. 3D and 3E  show perspective views of part of the fluid chamber of the closure device of  FIGS. 3A, 3B and 3C ; 
         FIGS. 4A, 4B and 4C  show schematic cross-sectional views of a closure device according to another embodiment of the present invention; 
         FIGS. 5A, 5B and 5C  show schematic cross-sectional views of a closure device according to another embodiment of the present invention; and 
         FIGS. 6A, 6B and 6C  show schematic cross-sectional views of a closure device according to another embodiment of the present invention. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Collapsible Flange Embodiment 
     With reference to  FIG. 1  there is shown a closure device  10  in a first closed position. The closure device  10  is depicted connected to the upper part of a container  34  that contains a fluid (not shown). The container depicted has a neck  38 . The container  34  may be, for example, a PET bottle. The container  34  may hold a variety of liquids such as water, or a pharmaceutical or glucose solution. The liquid may be for consumption, but may instead be a chemical composition for other use, such as cleaning, healthcare, hair dye application, painting or household maintenance. However, for the purposes of this description, the liquid held in the container  34  will hereinafter be referred to as the beverage. 
     The closure device  10  includes a cap member  36 . The closure device  10  is used to close an opening  40  in the neck  38  and is attached to the container  34  by the cap member  36 . The cap member  36  is detachably attached to the container neck  38  by a threaded arrangement. The threaded arrangement comprises an external thread  46  located on an outer surface of the container neck  38  that engages with an internal thread  42  located on an inner surface of the side wall  37  of the cap member  36 . Thus the cap member  36  can be unscrewed and removed by a user of the closure device  10 . All of the aforementioned components may be formed of polypropylene, or other suitable material. 
     Inside the cap member  36  a fluid chamber  60  is located. The fluid chamber  60  contains an additive liquid and a pressured propellant fluid. The fluid held in the fluid chamber  60  may be of significantly greater pressure than the beverage held in the container  34 . The fluid chamber  60  is enclosed by a fluid chamber wall  62 . The fluid chamber  60  may be formed using plastic injection moulding and may be formed of PET or any other suitable plastic. In the example of  FIG. 1  the fluid chamber  60  is formed by bonding the wall  62  to the underside of the cap member  36 . However the chamber  60  may be formed as a separate blow moulded chamber as in the embodiment of  FIG. 2 . 
     The fluid chamber  60  is surrounded by a housing  54  that sits within the container neck  38 . The housing  54  includes a cylindrical housing wall  56  that extends substantially parallel to the container neck  38 . At the top of the housing wall  56  is a collapsible flange member  58  which extends over the top of the container neck  38  to engage with a detent  80  formed on the inside of the side wall  37  of the cap member  36 . 
     The flange member  58  in the example of  FIG. 1  has a concertina arrangement. It is plastically deformable, and includes a number of radial slots which extend from the housing wall  56  to the perimeter of the flange member  58 , so the flange member  58  in plan has the appearance of a number of separate segments. 
     When an upwards force is applied to the flange member  58 , for example by the neck  38  when the cap member  36  is screwed down onto the neck  38 , the flange member  58  is deformed so that the overall diameter of the flange member  58  is reduced, and the flange member  58  no longer extends as afar out as the detent  80 . Hence the housing  54  is no longer retained within the cap member  36  by the coupling of the flange member  58  and the detent  80 . 
     The housing  54  may further comprise leg members that extend from the cylindrical wall  56  to a plug member  64 . Alternatively the housing wall  56  may extend itself to the plug member  64 . 
     Both the housing  54  and the plug member  64  may be formed by injection moulding or another suitable method. Typically the housing  54  fits with a friction fit in the neck  38 , so that it may resist a small force, but can be extracted from the neck without requiring a large force. 
     In the example of  FIG. 1  the plug member  64  is a cylindrical member which extends upwards from the base of the housing  54  and is adapted to engage sealingly with an aperture  66  in the fluid chamber  60 . The plug member  64  has a central bore  90  which is itself plugged by a spike plug member  92  fixed by a number of radial arms  94  to the top of the aperture  66  in the fluid chamber  60 . The bore  90  extends to an outlet nozzle  74  at the lower end of the plug member  64 . The plug member  64  has a coating of formed of a resilient, soft plastic or rubber material such as mouldable thermo plastic elastomer or nitrile rubber, which acts to form a seal between the plug member  64  and the aperture  66  in the fluid chamber  60 . 
     Alternatively the plug member may be similar to that illustrated in  FIG. 2 . In  FIG. 2  the plug member  164  of the housing is a cylindrical member which extends upwards from the base of the housing  54  and is adapted to engage sealingly with an aperture  66  in the fluid chamber  60 . 
     The plug member  164  includes a lateral passage  170  that extends between the outer walls of the plug member  164 . 
     The plug member  164  further includes a longitudinal internal nozzle passage  172  that extends downwards from the lateral passage  170  to a nozzle  174 . The plug member  164  has a coating of formed of a resilient, soft plastic or rubber material such as mouldable thermo plastic elastomer or nitrile rubber, which acts to form a seal between the plug member  164  and the aperture  66  in the fluid chamber  60 . Alternatively, separate O-ring seals could be utilised to form the seals between the plug member  164  and the aperture  66 . 
     The closure device  10  may include anti-tamper means (not shown) to prevent rotation of the cap member  36  relative to the container neck  38  and vertical lifting of the cap member  36 . 
     With reference to  FIG. 1 , the operation of the closure device is as follows. The closure device  10  can be assembled in a separate process and at a separate location from the filling process by which the container  34  is filled with a beverage. A liquid additive and a pressurised propellant are introduced into the fluid chamber  60  and the closure device is assembled to adopt the closed position illustrated in  FIG. 1 , for example by filing and assembling in a pressurised environment. In this position the internal pressure of the fluid chamber urges the plug member  64  out of the aperture  66 , and so urges the housing  54  downwards relative to the fluid chamber  60  and cap member  36 . However the engagement of the flange member  58  with the detent  80  prevents the separation of the housing  54  and cap member  36 , and maintains the plug member  64  in the aperture  66 . 
     The closure device  10  may be transported to the container filling station in the closed position. After the container  34  has been filled with a beverage, the closure device  10  is placed on the neck  38  of the container, still in the closed position. The closure device  10  is then lowered onto the neck of the container by screwing action until the top of the neck  38  of the container contacts the flange member  58  of the housing  54 . Further lowering of the closure device  10 , by further screwing action, onto the neck  38  of the container results in the neck  38  deforming the flange member  58  to a position in which the flange member  38  can no longer be engaged by the detent member  80 . The closure device  10  is screwed down as far as it can go, so the neck  38  presses the deformed flange member  58  against the underside of the cap member  36 , while the plug member  64  penetrates further into the aperture  66  in the fluid chamber  60 , and the closure device  10  is now in a second armed position. In the armed position the closure device  10  is ready to fire the additive through the nozzle  74 , but has not yet done so. 
     The container  34  and the closure device  10  remain in the armed position while the container  34  is transported to its point of sale or use. 
     When the container  34  is ready to be used, a user raises the closure device  10  on the neck  38  of the container, by unscrewing the cap member  26 , such that the cap member  36  and fluid chamber  60  are raised relative to the plug member  64 , and the closure device  10  is then in a third firing position in which a fluid communication path is provided from the fluid chamber  60  through the nozzle  74  of the plug member  64 . This firing position is similar to that described in detail in WO2007/129116, and is not described further here. In the firing position the plug member  64  is at least partially removed from the aperture  66 , and the additive liquid is urged from the fluid chamber  60  through the bore  90  and out of the nozzle  74  into the container  34  under pressure of the pressurised propellant in the fluid chamber  60 . The closure device  10  is now in the third firing position. 
     In practice one turn or less of the cap member  36  is required to move the closure device  10  from the armed position to the firing position. Further rotation of the cap member  36  allows the cap member  36  and the housing  54  to be removed from the neck of the container. In the embodiment of  FIG. 1  corresponding detents  82 ,  84  on the inner surface of the wall  56  of the housing  54  and the outer surface of the wall  62  of the fluid chamber  60  prevent the fluid chamber  60  being removed completely from the housing  54 . Hence as the cap member  38  is unscrewed, the low friction force holding the housing  54  in the neck  38  is overcome, and the closure device  10  is removed in its entirety. 
     The embodiment of  FIGS. 5A, 5B and 5C  is similar to the embodiment of  FIG. 1 , but has a different plug member  464 . Components which are similar to those illustrated in the embodiment of  FIG. 1  have the same reference number. The closure device  410  is shown in the closed, armed and firing positions in  FIGS. 5A, 5B and 5C  respectively. 
     The closure device  410  is adapted to be fitted to the neck  38  of a container that contains a fluid (not shown), for example, a PET bottle. 
     The closure device  410  includes a cap member  436  with a threaded side wall  437 . A fluid chamber or tank  460  is connected to the cap member  436 . In the example the cap member  436  includes a cylindrical wall  437  which surrounds the tank  460 , which may be formed separately. The cap member  436  is bonded or moulded to the tank  460 . 
     A separate housing  454  sits inside the neck  38  of the bottle. The casing includes a sleeve portion  440  which surrounds the tank  460  and has a plug member  464  at its lower end. At its upper end the housing  454  includes a collapsible flange  58  as described with reference to  FIG. 1 . 
     The fluid chamber  460  contains an additive liquid and a pressured propellant fluid. The fluid held in the fluid chamber  460  may be of significantly greater pressure than the beverage held in the container. The fluid chamber  460  is enclosed by a fluid chamber wall  462 . The fluid chamber  460  may be formed using plastic injection moulding and may be formed of PET or any other suitable plastic. In the example of  FIG. 5A  the fluid chamber  460  is formed as a separate blow moulded chamber and secured to the closure  436  by moulding the cap member  436  around it. However the fluid chamber  460  may be simply bonded to the cap member  436  by adhesive or formed by any other means. 
     The housing  454  and the plug member  464  may be formed by injection moulding or another suitable method. 
     In the closed or storage position of  FIG. 5A  and the armed position of  FIG. 5B  the fluid chamber  460  is sealed closed by a valve arrangement comprising an annular boss member  463  and the plug member  464 . The annular boss member  463  is formed from an open end of the cylindrical wall  462  of the tank  460 . In the example the annular boss member  463  has a wall thickness greater than the remainder of the tank wall  462 . The plug member  464  has an annular channel  470  arranged in the first upper side  472  of the plug member  464 . The channel  470  has inner and outer concentric side walls and a channel floor  471 . 
     The channel  470  has a first seal  474  provided on the inner concentric side wall of the channel  470  which seals between the plug member  464  and an internal surface of the annular boss member  463  in the closed and armed positions of  FIGS. 5A and 5B . The internal surface of the annular boss member  463  is an internal surface of the wall  462  of the tank  460 . 
     The channel  470  also has a second seal  476  provided on the outer concentric side wall of the channel  470  which seals between the plug member  464  and an external surface of the annular boss member  463  in the closed and armed positions of FIGS.  5 A and  5 B. The external surface of the annular boss member  463  is an external surface of the wall  462  of the tank  460 . 
     The annular channel  470  has one or more orifices  480  extending from the channel floor  471  through the plug member  464  to a second lower side  473  of the plug member  464  opposite the first upper side  472 . 
     The plug member  464  includes a stopper portion  478  which in the closed position projects inside the boss member  463 , and acts with the first and second seals  474 ,  476  to form a secure and positive seal, capable of maintaining the pressure within the pressurised tank  460 . The seals  474 ,  476  ensure that when the closure device  410  is in the closed and armed positions shown in  FIGS. 5A and 5B  the one or more orifices  480  are sealed closed and are not in communication with the interior volume of the tank  460 . 
     The cap member  436  optionally includes a detachable or frangible portion  490 , referred to as a tamper-evident band, of the type which is known in the art. The frangible portion  490  prevents the cap member  436  from being unscrewed from the neck  38  of the bottle until the frangible portion  490  has been removed. 
       FIG. 5C  shows the closure device  410  in the open or firing position. The frangible portion  490  has been separated from the cap member  436 , and the cap member  436  and tank  460  have been raised relative to the housing  454  and plug member  464 , so that the plug member  464  is no longer fully engaged with the open end of the tank  460 . The stopper portion  478  is below the annular boss member  463 , which no longer is engaged in the annular channel  470 . The one or more orifices  480  are now in communication with the interior volume of the tank  460 , so that the liquid additive is fired through the orifices under the action of the pressurised propellant in the tank  460 . 
     A further detent or stop mechanism (not shown) may be provided to prevent further rotation of the cap member  436  relative to the housing  454 , so that further rotation of the cap member  436  causes both the cap member  436  and housing  454  to be lifted on the threads of the neck  38  so that the closure device  410  can be removed from the neck  38  of the bottle. 
     Bridge Embodiment 
     The embodiment of  FIG. 2  operates in a similar way, as the closure device  110  moves between the three positions, closed, armed and firing. Like components have the same reference numerals as in the embodiment of  FIG. 1 . In the closure device  110  of  FIG. 2  the flange member  158  has a cantilever flange  160 , which extends in a cantilevered manner across all or part of the top of the container neck. The flange member  158  is connected to the housing wall by a plurality of bridge portions  162  of reduced thickness. The flange member  158  includes an abutment portion  159  which engages with a detent member  180  provided on the outer wall  62  of the fluid chamber  66 . 
     During the deformation step, when the cap member  36  is screwed down tightly onto the neck  38 , the flange member  158  is deformed by fracturing one or more bridge portions  162  so that the flange member  158  is separated from the housing wall  56  and the housing  54 . As a result the housing can no longer be engaged by the detent member  180 . The flange member  158  is pushed upwards relative to the detent member  180 , while the protruding part of the housing wall  56  just below the detent member  180 , formed by the “necking” of the wall  56  to form the bridge portions  162 , is restrained by the detent member  108  so that the bridge portions  162  are stretched until they break. In practice the bridge portions may be arranged around the perimeter of the housing wall  56 , with circumferential spaces in between. The bridge portions may be of the form of bridge portions known in tamper-proof bands. 
     In the embodiment of  FIG. 2  corresponding detents  182 ,  184  on the inner surface of an upstand wall  186  on the housing  54  and the outer surface of the aperture wall  162  of the fluid chamber  60  prevent the fluid chamber  60  being removed completely from the housing  54 . Hence as the cap member  38  is unscrewed, the low friction force holding the housing  54  in the neck  38  is overcome, and the closure device  10  is removed in its entirety. 
     Although illustrated with a plastic screw cap, the closure device of  FIGS. 1 and 2  can include a crown cap as the cap member. 
     Detachable Detent Embodiment 
     The embodiment of  FIGS. 3A, 3B and 3C  also operates in a similar way, and  FIGS. 3A, 3B and 3C  show the closure device  210  in the three positions, closed, armed and firing respectively. 
     The closure device  210  includes a crown cap  236 , which engages with a standard flange  202  provided on the neck  238  of a bottle  234 , typically a glass bottle. The flange  202  may be a threaded flange, so that the crown cap  236  can be removed by unscrewing, or the flange  202  can be unthreaded, so that the crown cap  236  is removed in the known way using a conventional bottle opener. 
     A fluid chamber  260  is attached to the underside of the cap member  236  by bonding. The fluid chamber  260  contains an additive liquid and a pressured propellant fluid. The fluid held in the fluid chamber  260  may be of significantly greater pressure than the beverage held in the container  234 . The fluid chamber  260  is enclosed by a fluid chamber wall  262 . The fluid chamber  260  may be formed using plastic injection moulding and may be formed of PET or any other suitable plastic. In the example of  FIG. 3A  the fluid chamber is shown as being formed of two components, including an upper portion  260 A which is attached directly to the cap member  236  and welded to the lower portion of the fluid chamber  260 . However any form of fluid chamber may be used, such as a single blow moulded fluid chamber  260  which may be bonded directly to the underside of a cap member  236 . 
     The fluid chamber  260  is surrounded by a housing  254  that sits within the container neck  238  in use. The housing  254  includes a cylindrical housing wall  256  that extends substantially parallel to the container neck  238 . At the top of the housing wall  256  is a flange member  258  which extends over the top of the container neck  238  when the closure device  210  is inserted in a container  234 . 
     A detachable detent member  204  is provided on the outside surface of the fluid chamber  260 , which forms part of the cap member  236 . The housing  254  has an internal rib  206  at the top of the cylindrical housing wall  256  which is adapted to engage with the detent member  204  to hold the closure device in the closed position illustrated in  FIG. 3A . Wthout the rib  206  the fluid chamber  260  would be free to lift under the action of the internal pressure of the fluid in the fluid chamber against the plug member  264 . 
     The housing  254  includes an abutment member  208 , in the form of an internal ledge or step below the flange  258 . The abutment member  208  is below the detent member  204  in the closed position of  FIG. 3A , and prevents lowering of the fluid chamber  260  relative to the housing  254  without removal of the detent member  204 . 
     The detent member  204  is shown more clearly in  FIGS. 3D and 3E . In the illustrated embodiment the detent member  204  is discontinuous and comprises a plurality of discrete detent portions  204 A,  204 B,  204 C. The detent portion is formed integrally on the upper portion  260 A of the fluid chamber  260 . The detent member  204  is connected to the fluid chamber wall  262  by narrow bridge portions  205 , so that the detent member  204  is detachable from the fluid chamber  260  by tearing. 
     The upper portion  260 A of the fluid chamber  260  also includes a detent  284  which is adapted to engage with a corresponding detent  282  on the housing  254 . As can be seen from  FIG. 4 , the detent  284  may also be discontinuous. The corresponding detents  282 ,  284  on the housing  254  and the fluid chamber  260  prevent the fluid chamber  260  being removed completely from the housing  254 . 
     The housing  254  may further comprise leg members  255  that extend from the cylindrical wall  256  to the plug member  264 . Alternatively the housing wall  256  may extend itself to the plug member  264 . 
     Both the housing  254  and the plug member  264  may be formed by injection moulding or another suitable method. Typically the housing  254  fits with a friction fit in the neck  238 , so that it may resist a small force, but can be extracted from the neck without requiring a large force. 
     In the example of  FIG. 3A  the plug member  264  of the housing  254  is a cylindrical member which extends upwards from the base of the housing  254  and is adapted to engage sealingly with an aperture  266  in the fluid chamber  260 . The plug member  264  includes a lateral passage  270  that extends between the outer walls of the plug member  264 . The plug member  264  further includes a longitudinal internal nozzle passage  272  that extends downwards from the lateral passage  270  to a nozzle  274 . The plug member  264  has a coating of formed of a resilient, soft plastic or rubber material such as mouldable thermo plastic elastomer or nitrile rubber, which acts to form a seal between the plug member  264  and the aperture  266  in the fluid chamber  260 . Alternatively, separate O-ring seals could be utilised to form the seals between the plug member  264  and the aperture  266 . 
     The operation of the closure device  210  is as follows. The closure device  210  can be assembled in a separate process and at a separate location from the filling process by which the bottle  234  is filled with a beverage. A liquid additive and a pressurised propellant are introduced into the fluid chamber  260  and the closure device is assembled to adopt the closed position illustrated in  FIG. 3A , for example by filing and assembling in a pressurised environment. In this position the internal pressure of the fluid chamber urges the plug member  264  out of the aperture  266 , and so urges the housing  254  downwards relative to the fluid chamber  260  and cap member  236 . However the engagement of the internal rib  206  with the detent member  204  prevents the separation of the housing  254  and cap member  236 , and maintains the plug member  264  in the aperture  266 . 
     The closure device  210  may be transported to the container filling station in the closed position. After the container  234  has been filled with a beverage, the closure device  210  is placed on the neck  238  of the container, still in the closed position of  FIG. 3A . The closure device  210  is then lowered onto the neck  238  of the container until the top of the neck  238  of the container contacts the flange member  258  of the housing  254 . Further lowering of the crown cap member  236  onto the neck  238  of the container results in the detent member  204  being deformed and separated from the fluid chamber  260  by tearing of the bridge portions  205  through the shearing action of the abutment  206 . 
     The crown cap member  236  is pushed down as far as it can go, and is engaged with the flange  202  on the bottle neck  238  in the conventional manner, by deformation of the side wall  237 . The plug member  264  penetrates further into the aperture  266  in the fluid chamber  260 , and the closure device  210  is now in the second armed position, as illustrated in  FIG. 3B . In the armed position the closure device  210  is ready to fire the additive through the nozzle  274 , but has not yet done so. 
     The container  234  and the closure device  210  remain in the armed position while the container  234  is transported to its point of sale or use. 
     When the container  234  is ready to be used, a user raises the closure device  210  on the neck  238  of the container  234 , by either unscrewing the cap member  236  or opening the cap member  236  with a lever action bottle opener, such that the cap member  236  and fluid chamber  260  are raised relative to the plug member  264 , and the closure device  210  is then in the third firing position, shown in  FIG. 3C , in which a fluid communication path is provided from the fluid chamber  260  through the nozzle  274  of the plug member  264 . This firing position is similar to that described in detail in WO2007/129116, and is not described further here. In the firing position the plug member  264  is at least partially removed from the aperture  266 , and the additive liquid is urged from the fluid chamber  260  through the bore  270  and out of the nozzle  274  into the container  234  under pressure of the pressurised propellant in the fluid chamber  260 . 
     The closure device  210  can then be removed from the bottle  234 . The corresponding detents  282 ,  284  on the inner surface of the wall  256  of the housing  254  and the outer surface of the wall  262  of the fluid chamber  260  prevent the fluid chamber  260  being removed completely from the housing  254 . Hence the low friction force holding the housing  254  in the neck  238  is overcome, and the closure device  210  is removed in its entirety. 
     The embodiment of  FIGS. 4A, 4B and 4C  operates in exactly the same way as the embodiment of  FIGS. 3A, 3B and 3C , and the operation is not further described. Like components have the same reference numerals as the embodiment of  FIGS. 3A to 3C . The only difference is in the nature of the plug member  364 , which in this embodiment is similar to the plug member  64  illustrated in  FIG. 1 .  FIGS. 4A, 4B and 4C  show the closure device  210  in the three positions, closed, armed and firing respectively. 
     The plug member  364  is a cylindrical member which extends upwards from the base of the housing  254  and is adapted to engage sealingly with an aperture  366  in the fluid chamber  260 . The plug member  364  has a central bore  390  which is itself plugged by a spike plug member  392  fixed by a number of radial arms  394  to the top of the aperture  366  in the fluid chamber  260 . The central bore  390  extends to an outlet nozzle  374  at the lower end of the plug member  364 . The plug member  364  has a coating  365  formed of a resilient, soft plastic or rubber material such as mouldable thermo plastic elastomer or nitrile rubber, which acts to form a seal between the plug member  364  and the aperture  366  in the fluid chamber  260 , and between the plug member  364  and the spike plug member  392 . 
     The embodiment of  FIGS. 6A, 6B and 6C  operates in exactly the same way as the embodiment of  FIGS. 3A, 3B and 3C , and the operation is not further described. Again the only difference is in the nature of the plug member  564 , which in this embodiment is similar to the plug member  464  illustrated in  FIGS. 5A, 5B and 5C . The same reference signs are used to denote components which are the same as those in  FIGS. 3A to 3C and 5A to 5C .  FIGS. 6A, 6B and 6C  show the closure device  510  in the three positions, closed, armed and firing respectively. The flange  202 , neck  238 , bottle  234  and crown cap  236  are not shown, but are similar to those in  FIGS. 3A to 3C . 
     Because the closure device of the present invention does not require a housing flange between the external thread of the bottle neck and the internal thread of an outer cap wall, the closure device of the present invention is no wider than a conventional closure. 
     The closure device of the present invention has a maximum of only one threaded connection so the problem with prior art closures, that the two threaded connections may not turn in the correct order, is eliminated. 
     The closure device of the present invention can operate with no threaded connection, making it suitable for use with crown corks and glass bottles. 
     The invention is not limited to the specific embodiments described, and modifications and alternatives are possible. The shape, material and size of the various components can be modified. In particular the shape and size of the flange portion can be varied, as can the nature of the deformation of the flange portion.