Patent Publication Number: US-2023148664-A1

Title: Cartridge for an Electronic Cigarette

Description:
The present invention relates to a cartridge for an electronic cigarette. 
     BACKGROUND 
     Electronic cigarettes are an alternative to conventional cigarettes. Instead of generating a combustion smoke, they vaporize a liquid, which can be inhaled by a user. The liquid typically comprises an aerosol-forming substance, such as glycerin or propylene glycol that creates the vapor. Other common substances in the liquid are nicotine and various flavorings. 
     The electronic cigarette is a hand-held inhaler system, comprising a mouthpiece section, a liquid store and a power supply unit. Vaporization is achieved by a vaporizer or heater unit which typically comprises a heating element in the form of a heating coil and a fluid transfer element, such as a wick, arranged to transfer fluid from the liquid store to the heating element. Vaporization occurs when the heater heats up the liquid in the fluid transfer element until the liquid is transformed into vapor. The vapor can then be inhaled via an air outlet in the mouthpiece. 
     The electronic cigarette may comprise a cartridge seating which is configured to receive disposable consumables in the form of cartridges. Cartridges comprising the liquid store and the vaporizer are often referred to as “cartomizers”. In this case, the vaporizer of the cartomizer is connected to the power supply unit when received in the cartridge seating such that electricity can be supplied to the heater of the cartomizer to heat the liquid to generate the vapor. Often some form of mechanical mechanism is used to retain the cartridge in the cartridge seating such that it does not fall out and separate from the device. 
     In order to transfer liquid from the liquid store to the heating element, the wick must be arranged between the liquid store and vaporization chamber such that, when the wick is heated, capillary action transports liquid through the porous structure of the wick from the liquid store to the hating element. A common problem with electronic cigarettes is leakage of liquid from the liquid store to the vaporization chamber, other than through the wick as intended. This results in liquid pooling in the vaporization chamber which can be transported in the air flow route to the mouthpiece, leading to large liquid droplets in the inhaled vapor which is unpleasant to a user. Similarly the liquid collecting in the vaporization chamber can come into contact with the electrical contacts of the heating element and it can leak through the air inlets in the cartridge seating itself, possibly causing degradation of the battery contacts and coating the electronic cigarette and cartridge making it unpleasant to handle. 
     It is an object of the present invention to provide an electronic cigarette which makes progress in solving some of the problems of prior art devices identified above. 
     SUMMARY OF THE INVENTION 
     In a first aspect of the invention there is provided a liquid store arranged to contain a liquid to be vaporized; a vaporization chamber having at least one opening which connects the vaporization chamber to the liquid store; a fluid transfer element held within the opening and extending between the liquid store and vaporization chamber, the fluid transfer element arranged to transfer liquid between the liquid store and vaporization chamber by capillary action; a heating element positioned within the vaporization chamber and arranged to heat a liquid transferred to the vaporization chamber by the fluid transfer element; wherein the cartridge comprises an upper housing portion and a lower housing portion which are configured to connect together around the fluid transport element to form the liquid store, the vaporization chamber and the at least one opening. 
     The upper housing portion and lower housing portion together preferably provide an outer housing of the cartridge. 
     As the cartridge housing comprises two parts which fit together to provide the opening holding the fluid transport element, a precisely dimensioned and positioned opening can be provided which is configured to closely fit around the fluid transport element to reduce leakage through the opening around the fluid transfer element. Furthermore the assembly process is simplified as the fluid transport element does not need to be fed through the opening but is simply enclosed within it as the two housing parts are connected together. By forming the liquid store, vaporization chamber and the connecting opening in this way the number of parts required is also reduced, which further simplifies the assembly process and reduces the manufacturing cost. Because the cartridge housing closes around the fluid transport element to form the openings, the position of the fluid transport element can be precisely configured and therefore the performance of the cartridge is improved over known devices in which the fluid transport element is first positioned within a vaporizer which is then positioned within a device, which can results in the numerous components not being correctly positioned, leading to leakage within the cartridge. This arrangement also allows for the liquid transport element to be held securely in place during assembly of the device, in particular for connection of the heating wire to the cartridge contact plates. 
     Preferably the fluid transport element is a capillary structure, for example a capillary wick preferably comprising a porous and/or fibrous structure. 
     The housing portions preferably provide the outer housing of the cartridge and preferably include one or more internal walls of divisions which, when connected together, define the liquid store, the vaporization chamber and the at least one opening. In some example of the invention the upper housing portion comprises the upper and side walls of the liquid chamber and the upper and side walls of the vaporization chamber and the lower housing portion comprises the base surface of the liquid store and the base surface of the vaporization chamber. 
     The vaporization chamber may be positioned substantially within the liquid store such that the liquid store at least partially surrounds the vaporization chamber. 
     Preferably the vaporization chamber comprises two openings which connect the vaporization chamber to the liquid store and the fluid transfer element is elongate; wherein the elongate fluid transfer element extends across the vaporization chamber with two opposing ends held within the openings and interfacing with the liquid store. In this way, liquid from the liquid store is more efficiently transported to the vaporization chamber through the capillary action of the liquid transport element. 
     Preferably, the upper housing comprises a curved upper supporting surface and the lower housing portion comprises an opposing curved lower supporting surface; wherein the upper and lower supporting surfaces together form the at least one opening holding the fluid transfer element when the upper and lower housing portions are connected together. In this way the curved surfaces meet the fluid transport element and may press into the sides of the fluid transport element to reduces leakage. Preferably the curved shape of the supporting surfaces fits the cross-sectional shape of the fluid transport element to provide a tight connection between the fluid transport element and supporting surfaces. 
     Preferably the upper supporting surface and lower supporting surfaces are semi-circular such that the at least one opening is circular when the upper and lower housing portions are connected together. Preferably the fluid transport element has a substantially circular cross section to match the opening. Preferably the diameter of the opening is less than the diameter of the wick. 
     In preferable examples of the invention the cartridge further includes an annular seal mounted in each of the one or more openings which connect the vaporization chamber to the liquid store; the annular seal engaged around the fluid transfer element such that liquid is restricted in passing through the opening other than through the liquid transfer element. In this way, the sealing around the fluid transport element is further enhanced to reduce leakage around the liquid transport element. Because the cartridge comprises two housing parts which are connected together to form the openings, the annular seals can be precisely positioned to optimize the sealing. 
     In some examples the annular seal comprises an upper seal segment attached to the upper housing portion and a lower seal segment attached to the lower housing portion; wherein the upper and lower seal segments together form the annular seal around the fluid transfer element when the upper and lower housing portions are connected. In this way, the annular seal is formed as the housing parts are connected. This removes the need to sleeve the annular seal on the wick prior during assembly and position the annular seal within the seating, which simplifies the assembly process. 
     In other example the cartridge comprises a curved upper supporting surface and the lower housing portion comprises an opposing curved lower supporting surface; wherein the corresponding upper and lower supporting surfaces provide a seating configured to receive the annular seal. Preferably the annular seal is an integral annular seal formed in a single part and is preferably sleeved on the fluid transfer element, prior to mounting in the cartridge. In this way a tighter connection around the fluid transfer element is provided which reduces the risk of parts of the fluid transfer element, such as loose fibers, coming away from the fluid transfer element and breaking the seal. 
     Preferably the upper and lower supporting surfaces are shaped to form a circumferential groove when the upper and lower housing portions are connected, wherein the circumferential groove is configured to receive the annular seal. A circumferential groove provides a reliable mount for the annular wick to hold it in place. Preferably the circumferential grooves comprises two circumferential surfaces forming a V-shaped cross-section and the annular seal comprises a rounded profile which meets both of the surfaces to provide two circumferential contacts between the annular seal and its seating. In this way, the annular seal meets the seating at two points along the axis of the annular seal which provides two sealing points to stop the passage of fluid around the fluid transfer element, through the opening, thus enhancing the sealing properties. 
     Preferably the annular seal comprises a substantially cylindrical body with a rounded circumferential protrusion extending radially outward to meet the surfaces bounding the openings. Preferably the length of the cylindrical body is greater than the length through the opening. This can aid in keeping loose fibers from the fluid transfer element getting between the contacting surfaces of the two housing parts when they are joined, The radially extending outward protrusion creates a tight seal against the seal seating of the opening. 
     The annular seal preferably comprises a substantially cylindrical body with an internal circumferential protrusion extending radially inward to press into the liquid transfer element within the seal. In this way, a tight seal between the annular seal and fluid transfer element is provided to minimize leakage through the annular seal. The distance of extension of the protrusion into the fluid transfer element also restricts fluid transport through the wick by compressing the capillary structure. The distance of radial extension of this protrusion can be configured to adapt the force pressing into the wick such that the balance between sealing around the wick and the restriction of fluid transfer through the wick can be tailored appropriately. Preferably the width of the inner protrusion is less than the width of the outer protrusion. 
     Preferably the seal comprises an elastic deformable material, for example silicone. In this way the seal deforms around the shape of the supporting surfaces and/or the fluid transfer element to further limit leakage. 
     Preferably the contacting surfaces of the upper housing portion and the lower housing portion when connected define a plane which runs lengthwise through the liquid transport element. In particular the plane of connection between the upper and lower housing portions runs through the liquid transport element. Otherwise stated, the upper and lower housing portion comprise surfaces of the outer housing which meet when the upper and lower housing portions are connected, the plane defined by these surfaces when connected runs through the liquid transport element, preferably through the center of the liquid transport element, preferably along the elongate axis. This improves the ease of assembly of the housing parts around the fluid transport element. 
     Preferably, the lower housing portion comprises air inlets to allow air into the vaporization chamber; wherein the air inlets are provided on a raised portion of a lower internal surface of the vaporization chamber. In this way, even if liquid were to leak into the vaporization chamber, because the air inlets are provided on raised surfaces above the inner base surface of the vaporization chamber, liquid will collect on the base surface but will not leak through the air inlets into the device. Furthermore, it will not enter the air stream such that large un-vaporized liquid droplets in the inhaled vapor are reduced. In some examples, a liquid absorbing material is provided on the lower internal surface of the vaporization chamber around the raised portions in order to collect and store any liquid collecting in this region to prevent it reaching the air inlets if the orientation of the device is changed. 
     In a further aspect of the invention there is provided an electronic cigarette comprising the cartridge as defined in any of the claims and a power source arranged to provide power to the heating element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1 A and  1 B  show a cartridge for an electronic cigarette according to the present invention; 
         FIGS.  2 A and  2 B  show a cartridge for an electronic cigarette according to the present invention which does not use an annular seal; 
         FIGS.  3 A to  3 B  illustrate details of a cartridge for an electronic cigarette according to the present invention; 
         FIG.  4    illustrates an aerosol generating device configured to receive a cartridge according to the present invention; 
     
    
    
     DETAILED DESCRIPTION 
       FIGS.  1 A and  1 B  schematically illustrate a cartridge  100  for an electronic cigarette according to the present invention. The cartridge  100  includes a liquid store  30  arranged to contain a liquid to be vaporized and a vaporization chamber  40 , where the vaporization chamber  40  has at least one opening  60  which connects the vaporization chamber  40  to the liquid store  30 . A fluid transport element  50  extends between the liquid store  30  and the vaporization chamber  40  and is supported within the opening  60 . The fluid transfer element  50  is arranged to transfer liquid between the liquid store  30  and the vaporization chamber  40  by capillary action. A heating element  41  is positioned within the vaporization chamber  40  and is arranged to heat the liquid that is transferred by capillary action to the vaporization chamber  40  by the fluid transfer element  50 . As most clearly shown in  FIG.  1 B  the cartridge comprises an upper housing portion  10  and a lower housing portion  20  which are configured to connect together around the fluid transfer element  50  to form the liquid store  30 , the vaporization chamber  40  and the at least one opening  60  connecting the vaporization chamber  40  and the liquid store  30 . 
     The cartridge according to the present invention improves that use of assembly and allows for a fluid transfer element  40  or “wick”  40  to be positioned so as to be tightly fitted within the opening  60  connecting the vaporization chamber  40  and liquid store  30 , thereby reducing leakage from the liquid store through the opening  60  into the vaporization chamber  40 . This “tight fit” of the fluid transfer element reduces the amount of liquid that normally tends to travel along the surface of a fluid transfer element. The present arrangement therefore forces the liquid transportation through the interior of the fluid transfer element by capillary action, which leads to a more controlled flow. Moreover, the flow of liquid through the fluid transfer element essentially only takes place during vaporization as liquid is drawn by capillary action in order to compensate for the liquid being vaporized in the contact area with the heating element. This improves the user experience by reducing the amount of large liquid droplets entering the vaporization chamber  40  and accordingly being inhaled by a user rather than solely be vapor generated by the heater  41 . 
     Because the cartridge is formed of two housing components  10 ,  20  which fit around the fluid transfer element to define the openings and the vaporization chamber  40  and liquid store  30  when connected together, the fluid transfer element  50  may be positioned in a straightforward manner with the housing components closed around it, rather than requiring the fluid transfer element to in some way be threaded into an opening within the housing. The present invention therefore allows for the wick  50  to be tightly fitted in an improved cartridge in which the ease of manufacture is enhanced. 
     In the example of the present invention shown in the figures the fluid transfer element  50  is in the form of a capillary wick  50  which may be formed for example by a bundle of fibers such as cotton fibers or another porous structure which is configured to transport liquid from the liquid store  30  through to the vaporization chamber  40  via capillary action through the porous wick structure, driven by the evaporation of liquid from the center of the wick by the heating element  41 . The fluid transport element  50  preferably comprises an elastic or compressible material such that it is compressible in a radial direction. In this way, the upper and lower housing portions  10 ,  20  compress the wick at the engagement points to restrict passage of the liquid through the openings, as will be described. The two housing portions  10 ,  20  together form a central vaporization chamber  40  and surrounding liquid store  30 . In particular, as shown in  FIG.  1 B  the upper housing portion  10  includes an outer wall  11  forming the outer boundary of the liquid store  30  and a number of internal walls  12 ,  13 . In particular the upper housing portion  10  includes a tubular central wall  12  which defines a tubular air flow passage aligned along the elongate axis of the cartridge which leads from the vaporization chamber  40  to an inhalation outlet  43  at a mouth end of the cartridge  100 . The internal side wall  12  forming the inhalation passage  42  within the surrounding liquid store  30  extends radially outwards around the wick  50  and heater  41  to form the outer bounds of the vaporization chamber  40  around the fluid transfer element  50 . As shown in  FIG.  1 B  the internal walls  12  forming the air flow passage to the mouthpiece are connected to the walls  13  of the vaporization chamber  40 . The internal vaporization chamber walls  13  form part of the side walls and upper walls which define the upper portion of the vaporization chamber  40  when the cartridge  100  is assembled. 
     The lower housing portion  20  comprises an outer housing wall  21  defining the outer bounds of the housing portion  20 . As most clearly shown in  FIG.  2 A  the lower housing portion  20  also has a number of internal walls  23  which, together with the internal walls  13  of the upper housing portion  10 , form the internal walls defining the volume of the vaporization chamber  40 . In particular, the lower housing portion has an internal lower base wall  22 , shown in  FIG.  1 A , and two internal side walls  23 , as shown in  FIG.  2 A . As shown in  FIG.  1 A , the internal walls  13 ,  23  of the upper housing portion  10  and lower housing portion  20  fit together when the upper and lower housing portions  10 ,  20  are connected to define the outer bounds of the vaporization chamber  40 , within the internal volume of the cartridge  100  defined by outer side walls  11  and  21  of the upper and lower housing portions. In this way, the internal vaporization chamber  40  is partially surrounded by the liquid store  30 . In particular, the internal walls are shaped so as to provide a vaporization chamber  40  centrally within the internal volume of the cartridge, with the volume of the liquid store defined at least partially around it extending down on at least two opposing sides of the vaporization chamber  40 . 
     This structure differs to known devices in that two integral housing portions, the upper and lower housing portions  10 ,  20 , together form the outer housing of the cartridge and each of the vaporization chamber  40 , liquid store  30  and the connecting openings  60 . Known devices often require the insertion of separate components within the outer housing to provide the vaporization chamber and therefore require much more complex assembly and alignment of components which, when not precisely achieved, can lead to leakage. 
     As shown in  FIGS.  2 A and  2 B , the internal side walls  13 ,  23  provided by the upper  10  and lower  20  housing portions which define the vaporization chamber  40  each comprise curved surfaces  61 ,  62  which together also form the opening  60  which connects the liquid store and heating chamber  40  when the housing portions are connecting together. In this way, the vaporization chamber  40  is provided centrally within the internal volume of the cartridge  100  with, in the example of the figures, two openings  60  within the side walls of the vaporization chamber, which place the vaporization chamber in fluid communication with the surrounding liquid store  30 . As shown in  FIG.  2 A , the surfaces  62  which define the opening  60 , support the ends  51  of the capillary wick  50 , such that when the housing portions  10 ,  20  are brought together the ends  51  of the capillary wick are tightly received within the opening  60  formed by the surfaces  61 ,  62  as shown in  FIGS.  1 A and  1 B . 
     In the example of the figures, the fluid transfer element  50  is an elongate capillary wick as shown in  FIG.  2 A  which extends across the internal volume of the heating chamber  40  with its opposing ends  51  received in the openings  60  within the internal side walls of the vaporization chamber  40 . In this way, when the housing portions are brought together as shown in  FIG.  1 B  and the internal volume of the liquid store  30  is filled with liquid, the capillary wick fills the openings  60  such that the ends  51  of the wick are in communication with the liquid within the internal volume of the liquid store  30  and liquid is drawn into the vaporization chamber  40  through the capillary wick  50  during heating. Since the openings  60  are formed by the opposing surfaces  61 ,  62  of two separate housing parts  10 ,  20  the construction of the cartridge  100  is simplified and a tighter connection of the opening  60  around the wick  50  can be achieved. 
     A known problem in such devices is constricting the wick with sufficient pressure within the opening  60  connecting the liquid store  30  and vaporization chamber  40  so as to not allow liquid to leak around the wick into the vaporization chamber, whilst not applying excessive pressure such that transport of liquid through the interstices formed by the fibers of the wick  50  such that fluid transport through the wick  50  is restricted. By providing the opening  60  in the form of two constituent parts which are fitted together around the wick  50  the diameter of the opening  60  can be precisely engineered to provide the required tight fit whilst still allowing sufficient liquid flow through the capillary wick  50 . Furthermore, the shape of the upper and lower  61 ,  62  supporting surfaces which form the opening  60  holding the wick  50  can be provided with specific shapes or surface features to securely hold the wick with the correct pressure. In the example of the figures, the supporting surfaces are semi-circular in shape to together form a substantially circular opening  60 . The surfaces may be formed for example with a circumferential protrusion which presses into the capillary wick  50  to restrict liquid flow around the wick  60 . 
     As shown most clearly in  FIG.  2 A , the heating element is a heating coil  41  which is coiled around the wick and has two ends  42  which extend out from the wick to contact electrical contact plates  70 . By providing power to the electrical contact plates  70  and subsequently to the heating element the current can be provided through the heating element to heat the electrical coil and vaporize a liquid transported from the liquid store  30  through the liquid transport element  50  within the vaporization chamber  40 . 
     In the example of  FIGS.  2 A and  2 B  the capillary wick  50  is simply received within the opening  60  formed by the supporting surfaces  61 ,  62  of the upper  10  and lower  20  housing portions. Preferably, the sealing of the opening around the capillary wick  50  is further enhanced by the use of annular seals  80  which are mounted in each opening  60  wherein the annular seals  80  are engaged around the fluid transfer element  50  such that liquid is restricted in passing through the opening  60  other than through the liquid transfer element  50 , as shown in  FIG.  1 A . The annular seals  80  are preferably made of a deformable elastic material and bound the parameters of the opening  60  such that the capillary wick  50  passes through the annular seals  80  within each opening  60  to interface with the liquid store  30 . The annular seals  80  provide a tight engagement with the supporting surfaces  61 ,  62  to substantially restrict the passage of liquid around the wick  50  through the opening  60  into the vaporization chamber  40 . 
     The annular seals  80  may be provided in a number of different ways. In one example, the annular seals  80  may comprise two components, an upper seal segment  80   a  which is attached to the upper supporting surface  61  of the upper housing portion  10  and a lower seal segment  80   b  which is attached to the lower supporting surfaces  62  of the lower housing portion  20 . In particular, the annular seals  80  may be formed by the curved supporting surfaces  61 ,  62  themselves being formed of an elastic deformable material such that when the housing portions  10 ,  20  are connected together around the wick  50  the seal segments  80   a,    80   b  form a complete annular seal  80  around the wick  50  to seal the openings  60 . For example, looking at  FIG.  1 A  the annular seal  80  may be formed by upper seal segment  80 A and lower segment  80 B, attached to the lower housing portion  20 , such that when the housing portions  10 ,  20  are brought together they form a complete annulus around the capillary wick  50 . 
     Alternatively, the upper supporting surface  61  in the upper housing portion  10  and the lower supporting surface  62  in the lower housing portion  20  may provide a seal seating configured to receive an integral annular seal  80 , as shown in  FIG.  3 A  in a plan view of the liquid transfer element  50  received in the lower housing portion  20 . As shown in  FIG.  3 A , the lower supporting surfaces are shaped to form a groove  63  which is configured to receive the annular seal  80 . A corresponding groove is provided by the upper supporting surfaces  61  as shown in  FIGS.  3 B and  2 B . In this way, the upper and lower supporting surfaces  61 ,  62  form a seating which retains an integral annular seal  80  in place within the opening  60 . A cross section of such an annular seal  80  when received in the seating provided by the groove  63  is shown in  FIG.  3 B . As shown in  FIG.  3 B  the circumferential groove  63  comprises two circumferential surfaces which form a V shaped cross section. 
     In particular, the upper supporting surface  61  comprises angled circumferential surfaces  61   a  and  61   b  which together form a V-shaped cross section of the circumferential groove  63 . Similarly, the lower supporting surfaces provided by the lower housing portion comprise angled supporting surfaces  62   a,    62   b  which together form a V-shaped cross section such that, when the upper  10  and lower  20  housing portions are connected together a complete circumferential V-shaped groove is provided around the opening  60 , as shown in  FIG.  3 B . This V-shaped groove acts to hold the annular seal  80  in place forming a tight connection to prevent it being dislodged and to provide a tight seal to prevent the passage of liquid. The annular seal  80  itself may be configured with a number of additional features to further enhance the sealing properties are provided by the annular seal  80  within the opening  60 . 
     As shown in  FIG.  3 B , the annular seal  80  comprises a substantially tubular body  81  formed in this example of a cylindrical main body  81 . The seal  80  also includes a rounded circumferential protrusion  82  extending radially outward around the circumference of the annular seal  80 , as clearly shown in  FIG.  3 A . The rounded profile of this protrusion  82  meets the two surfaces forming the V-shaped groove  63  to provide enhanced sealing properties. In particular because the rounded profile of the protrusion  82  meets the two angled surfaces  61   a,    61   b  of the upper housing  10  and the angled surfaces  62   a,    62   b  of the lower housing  20 , the annular seal provides two sealing points along the tubular axis of the annular seal  80 . In particular, the contact points on each of these angled surfaces provide a complete circumferential contact line such that the seating provided by the supporting surfaces and the annular seals together provide two circumferential contact lines around the opening  60  which significantly restrict the passage of liquid around the annular seal  80  into the vaporization chamber  40 . The annular seal  80  of this example also includes an internal circumferential protrusion extending radially inward from the cylindrical body  81  to press into the capillary wick  50 . By configuring the length of radial extension of this internal circumferential protrusion  83 , the tightness of the grip on the wick  50  can be configured to optimize the seal  80  to prevent the passage of liquid between the wick  50  and the annular seal  80  whilst allowing the capillary transport of liquid through the wick  50 . 
     As described above the seal preferably comprises an elastic deformable material which deforms under the contact force against the angled surfaces forming the seating  63  and so conforms to the surfaces of the seating and the wick  50  to provide a tight seal. Silicone provides a particularly preferably material which can be adapted to provide the right degree of elasticity and can be produced in a straightforward manner by moulding. 
     As shown in  FIGS.  2 A and  2 B  the upper housing portion and lower housing portion  20  contact each other around the perimeter of the cross section of the outer walls  11 ,  21  at corresponding contacting surfaces  14 ,  24 . In particular, the upper and lower housing portions  10 ,  20  are brought together in the direction of the arrow in  FIG.  1 B  such that the upward facing contact surface  24  of the outer wall  21  of the lower housing portion comes into contact with the opposing downward facing contact surface  14  of the outer wall  11  of the upper housing portion  10 . These contacting surfaces may be attached by a number of different manufacturing techniques such as via an adhesive or ultrasonic welding. Preferably this plane of connection defined by the opposing contacting attachment surfaces  24 ,  14  defines a plane of connection L shown in  FIG.  1 A  which runs centrally through the elongate axis of the capillary wick  60 . This aids in manufacture and allows the wick to be placed on the supporting surfaces and the opposing attachment surfaces bonded together to attach the housing portions  10 ,  20 . 
     As described above the coiled heating wire  41 , coiled around the wick, is contacted to the contacting plates  70 , as most clearly shown in  FIG.  3 A . In particular, there are two contacting plates  70  which extend upwards from the base surface  22  of the vaporization chamber  40  provided by the lower housing portion  20 . Each contacting plate  70  is preferably formed by an upwardly extending portion  71  which extends upwards approximately perpendicular to the base surface  22  of vaporization chamber  40  and a folded perpendicular portion  72  which lies flat along an outer surface at the base of the lower housing portion  20 . The contacting plates  70  are folded to form a perpendicular arrangement with the top wire-contacting portion  71  extending through an opening in the lower housing portion  20  and folded to form the second base contact portion  72  lying flush along the base surface  25  of the lower housing portion  20 . In this way when the cartridge  100  is received in an aerosol generating device the base contact portion  72  of the contacting plates  70  may contact corresponding contacts which are connected to the battery to provide current through the contact plate  70  to the heating wire  41 . 
     As shown in  FIG.  3 C  the top portion  71  of the contact plate  70  extends through raised portions  26  of the lower internal surface  22  of the vaporization chamber  40 . In particular, the base surface is formed by the lower internal surface  22  of the lower house portion and this has two protruding platforms  26  which extend upwardly from the base surface  22  and the wire engaging portion  71  of the contacting plates emerge from holes within these raised platforms  26  as shown in  FIG.  3 A . 
     By providing the contact plates  70  within raised platform portions  26  of the base of the vaporization chamber  22 , even if a small amount of liquid leaks passed the improved seal provided by the present invention, then this liquid will collect around the raised platforms  26  as shown in  FIG.  3 C , and not be in contact with the electrical terminals  70 . The air inlets to the vaporization chamber  43 , shown in  FIG.  3 A  are also provided through these raised platforms  26  such that, again, a liquid which leaks through pass the seals  80  is collected in the bottom of the vaporization chamber  40  and so droplets from any leaked liquid cannot get into the vapor flow stream through the air inlet  43  as these are provided below the inlets  43  at the base of the vaporization chamber. In this way, the improved sealing provided by the opening  60  around the wick  50 , together with the raised platforms  26  means that the amount of liquid droplets reaching the air flow through the mouth piece is significantly reduced. 
     Although in the illustrated embodiments the contact plates  70  are provided on the same side of the wick providing the fluid transport element  50  (i.e. both contact plates  70  are positioned adjacent to the same longitudinal side of the fluid transport element  50 ), in other embodiments the contact plates  70  may be positioned on opposite sides of the fluid transport element  50 . By positioning the contact plates  70  on opposite sides of the fluid transport element  50  (i.e. arranging the contact plates  70  such that the fluid transport element  50  runs between the contact plates), the contact plates may provide additional thermal insulation to the heating wire  41  and wick, thereby enhancing the efficiency of the device. 
     As shown in  FIG.  4    the cartridge  100  is configured to be received in the cartridge seating  201  of an aerosol generating device  200 . The contacts  72  on the outer base surface  25  of the lower housing portion  20  contact corresponding contacts  202  positioned at the base surface of the cartridge seating  201 . These contacts  202  may be spring biased such that they retract under contact back into recesses within the base of the cartridge seating  201 . The bias ensures that there is a sufficient contact between the contact  202  of the aerosol generating device and those  72  of the cartridge  100 . When the cartridge is received in the cartridge seating  201  current provided by a battery  203  may be provided to the contacts  72  and to the heating element  41  to vaporize liquid transported from the liquid chamber  30  to the vaporization chamber via the liquid transport element  50 . Wherein the provision of the current can be controlled by control circuitry  204  to control the amount of current applied to the heating element  41 . 
     With the cartridge  100  according to the present invention an increased resistance to leakage into the vaporization chamber is achieved, whilst providing a simplified manufacturing process. In particular, by providing a two part cartridge with an upper and lower housing portion  10 ,  20  which can be connected around the fluid transport element  50  to provide the openings between the liquid store  30  and the vaporization chamber  40 , an improved tight connection can be provided around the fluid transport element  50  to minimize leakage into the vaporization chamber. This can be improved further by the provision of annular seals  80  which are received in a seating provided by the opposing surfaces of the upper and lower housing portions  10 ,  20  which provide the opening  60  when connected. In this way, when the cartridge  100  is received in an aerosol generating device  200  as shown in  FIG.  4    there is less leakage through the air inlets into the cartridge seating  202  which accordingly prolongs the life of the device and ensures it continues to operate effectively. Furthermore, the user experience is further improved as less aerosol generating liquid stored in the liquid store  30  travels into the vaporization chamber and less is carried as large droplets during inhalation by the user.