Patent Publication Number: US-2022218033-A1

Title: Aerosol provision device

Description:
TECHNICAL FIELD 
     The present invention relates to an aerosol provision device, a method of generating an aerosol using the aerosol provision device, and an aerosol-generating system comprising the aerosol provision device. 
     BACKGROUND 
     Articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. Attempts have been made to provide alternatives to these types of articles, which burn tobacco, by creating products that release compounds without burning. Apparatus is known that heats smokable material to volatilise at least one component of the smokable material, typically to form an aerosol which can be inhaled, without burning or combusting the smokable material. Such apparatus is sometimes described as a “heat-not-burn” apparatus or a “tobacco heating product” (THP) or “tobacco heating device” or similar. Various different arrangements for volatilising at least one component of the smokable material are known. 
     The material may be for example tobacco or other non-tobacco products or a combination, such as a blended mix, which may or may not contain nicotine. 
     SUMMARY OF INVENTION 
     According to a first aspect of the present invention, there is provided an aerosol provision device comprising: a heating chamber for receiving the aerosol-generating material; an inductive heating unit for heating the aerosol-generating material during a session of use; and a conduit having an interior surface, the conduit fluidically connecting the heating chamber with the exterior of the aerosol provision device; wherein the aerosol provision device is configured so that the interior surface of the conduit is heated during a session of use to thereby substantially prevent accumulation of condensation within the conduit. 
     According to a further aspect of the present invention, there is provided an aerosol provision device for generating aerosol from aerosol-generating material, the aerosol provision device comprising: a heating chamber for receiving the aerosol-generating material; an inductive heating unit for heating the aerosol-generating material during a session of use, when the aerosol-generating material is located in the heating chamber; and a conduit having an interior surface, the conduit fluidically connecting the heating chamber with the exterior of the aerosol provision device; wherein the aerosol provision device is configured so the interior surface of the conduit is heated during the session of use, so that at least a portion of the interior surface attains a temperature greater than or equal to 85° C. 
     According to a still further aspect of the present invention there is provided an aerosol provision device for generating aerosol from aerosol-generating material, the aerosol provision device comprising: a heating chamber for receiving the aerosol-generating material; a heating unit for heating the aerosol-generating material during a session of use; and a conduit having an interior surface, the conduit fluidically connecting the heating chamber with the exterior of the aerosol provision device; wherein at least a portion of the interior surface has a thermal conductivity greater than or equal to 1 W/m/K. 
     According to a still further aspect of the present invention there is provided an aerosol provision device for generating aerosol from aerosol-generating material, the aerosol provision device comprising: a heating chamber for receiving the aerosol-generating material; a heating unit for heating the aerosol-generating material during a session of use; and a conduit having an interior surface, the conduit fluidically connecting the heating chamber with the exterior of the aerosol provision device; wherein the aerosol provision device is configured so the interior surface of the conduit is heated during the session of use and thereby at least a middle portion of the interior surface, which is mid-way between the proximal and distal ends of the conduit, attains a temperature greater than or equal to 70° C. 
     According to another aspect of the present invention there is provided an aerosol provision device for generating aerosol from aerosol-generating material, the aerosol provision device comprising: a heating chamber for receiving the aerosol-generating material; a heating unit for heating the aerosol-generating material during a session of use; a conduit fluidically connecting the heating chamber with the exterior of the aerosol provision device; and an air heating unit for heating air within the conduit to thereby substantially prevent accumulation of condensation within the conduit. 
     According to yet a further aspect of the present invention there is provided an aerosol provision device for generating aerosol from aerosol-generating material, the aerosol provision device comprising: a heating assembly comprising an inductor; a heating chamber for receiving the aerosol-generating material and within which the aerosol-generating material is heatable by the heating assembly; and a conduit fluidically connecting the heating chamber with an opening at an exterior of the aerosol provision device, wherein at least a portion of the conduit is defined by a component comprising a first susceptor; wherein the device is configured such that the first susceptor is heatable by the inductor to heat the conduit, thereby to substantially prevent accumulation of condensation within the conduit. 
     According to a still further aspect of the present invention there is provided an aerosol provision device for generating aerosol from aerosol-generating material, the aerosol provision device comprising: a heating assembly comprising a heating element that is heatable by the heating assembly; a heating chamber for receiving the aerosol-generating material and within which the aerosol-generating material is heatable by the heating element; and a conduit fluidically connecting the heating chamber with an opening at an exterior of the aerosol provision device, wherein at least a portion of the conduit is defined by a component comprising thermally conductive material; wherein the thermally conductive material of the component abuts the heating element so as to be heatable by thermal conduction from the heating element to heat the conduit, thereby to substantially prevent accumulation of condensation within the conduit. 
     According to yet another aspect of the present invention there is provided an aerosol provision device for receiving an article comprising aerosol-generating material and for generating aerosol from the aerosol-generating material, the aerosol provision device comprising: a stop, which prevents a distal end of the article from moving distally beyond a limit position when the article is inserted in the aerosol provision device; and a heating assembly for heating the aerosol-generating material during a session of use, the heating assembly comprising a heating element, within which heat is generated during use of the heating assembly; wherein, when the article is fully inserted into the device with the distal end of the article located at the limit position, there is a first portion of a length of the article that does not overlap with any heating element that is heatable to heat the article, the first portion extending either a first distance proximally from the distal end of the article, or a first distance distally from a proximal end of the article. 
     According to yet another aspect of the present invention there is provided an aerosol provision device for generating aerosol from aerosol-generating material, the aerosol provision device comprising: a heating assembly; and one or more components that define: a heating chamber for receiving the aerosol-generating material and within which the aerosol-generating material is heatable by the heating assembly; and a conduit fluidically connecting the heating chamber with an exterior of the aerosol provision device; wherein the one or more components provide a hermetic seal where the heating chamber and the conduit meet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a front view of an example of an aerosol provision device; 
         FIG. 2  shows an enlarged cross-sectional view of a heating assembly within an aerosol provision device; 
         FIG. 3 a    is close-up view of a cross-section through a modified version of the device of  FIGS. 1 and 2 , which includes a layer of thermally conductive material on the interior surface of the inlet conduit; 
         FIG. 3 b    is a close-up view of a cross-section through an alternative modified version of the device of  FIGS. 1 and 2 ; 
         FIG. 3 c    is a close-up view of a cross-section through a further modified version of the device of  FIGS. 1 and 2 ; 
         FIG. 3 d    is a close-up view of a cross-section through a still further modified version of the device of  FIGS. 1 and 2 ; 
         FIG. 4  is close-up view of a cross-section through a modified version of the device of  FIGS. 1 and 2 , which includes an air heating unit for heating air within the inlet conduit of the device; 
         FIG. 5 a    is close-up view of a cross-section through a modified version of the device of  FIGS. 1 and 2 , which includes an inductively heated component defining the inlet conduit; 
         FIG. 5 b    is a schematic view of an alternative modified version of the device of  FIGS. 1 and 2 , which includes respective inductively heated components defining the inlet and outlet conduits; 
         FIG. 6 a    is a schematic view of another modified version of the device of  FIGS. 1 and 2 , in which components defining the conduits and heating chamber are sealingly joined to one another; 
         FIG. 6 b    is a schematic view of a modified version of the device of  FIG. 6 a   , in which respective inductors are provided for causing the heating of the components defining the inlet conduit, the outlet conduit and the heating chamber; 
         FIG. 6 c    is a schematic view of yet another modified version of the device of  FIGS. 1 and 2 , in which a unitary component defines the inlet and outlet conduits and heating chamber; 
         FIG. 6 d    is a schematic view of a modified version of the device of  FIG. 6 c   , in which respective inductors are provided for causing the heating of the components defining the inlet conduit, the outlet conduit and the heating chamber; 
         FIG. 7 a    is close-up view of a cross-section through a modified version of the device of  FIGS. 1 and 2 , which is configured such that a distal end portion of the aerosol-generating material in an inserted article is unheated; 
         FIG. 7 b    is schematic view of an alternative modified version of the device of  FIGS. 1 and 2 , which is configured such that proximal and distal end portions of the aerosol-generating material in an inserted article are unheated; 
         FIG. 8  shows a front view of the aerosol provision device of  FIG. 1  with an outer cover removed; 
         FIG. 9  shows a cross-sectional view of the aerosol provision device of  FIG. 1 ; 
         FIG. 10  shows an exploded view of the aerosol provision device of  FIG. 1 ; 
         FIG. 11A  shows a cross-sectional view of a heating assembly within an aerosol provision device; and 
         FIG. 11B  shows a close-up view of a portion of the heating assembly of  FIG. 11A . 
     
    
    
     DETAILED DESCRIPTION 
     To facilitate formation of an aerosol in use, aerosol-generating material for aerosol provision devices (e.g. tobacco heating products) usually contains more water and/or aerosol-generating agent than the smokeable material within combustible smoking articles. This higher water and/or aerosol-generating agent content can increase the risk of condensate collecting within the aerosol provision device during use, particularly in locations away from the heating unit(s). 
     The inventors consider that this problem may be greater in devices with enclosed heating chambers. In such devices, the heating chamber may be fluidically connected with the exterior of the device by a conduit, for example an inlet or outlet conduit. Having studied the results of tests of devices having such conduits, the inventors consider that there is a particular risk that condensate collects within the conduits. 
     Such collected condensate may, in some cases, leak out of the device, leading to a less pleasant smoking experience for the user. In addition, or instead, such condensate may dry out over time, potentially forming a gum on the interior surfaces of the conduits. This gum may be difficult to remove and may therefore agglomerate over time. Furthermore, where the aerosol-generating material is contained within a consumable, the gum may adhere to the consumable, potentially discolouring it or hindering its removal after use. 
     The inventors have, however, determined that, by configuring the device so that the interior surface of a given conduit is heated during a session of use, the accumulation of condensate within the conduit in question may be limited and, in some cases, substantially prevented. In particular, the deposition of condensate on the interior surfaces of the conduit may be reduced. 
     Reference is directed to  FIG. 1 , which is a side view of an example of an aerosol provision device  100  for generating aerosol from an aerosol-generating medium/material. In broad outline, the device  100  may be used to heat a replaceable article  110  comprising the aerosol-generating medium, to generate an aerosol or other inhalable medium which is inhaled by a user of the device  100 . 
     The device  100  comprises a housing  102  (in the form of an outer cover) which surrounds and houses various components of the device  100 . The device  100  has an opening  104  in one end, through which the article  110  may be inserted for heating by a heating assembly. In use, the article  110  may be fully or partially inserted into the heating assembly where it may be heated by one or more components of the heater assembly. 
       FIG. 2  depicts a cross-section of selected internal components of the device  100  of  FIG. 1 . As shown, the device  100  includes a heating chamber  101  for receiving the aerosol-generating material  110   a . The device  100  additionally includes an inlet conduit  103   a , which fluidically connects the heating chamber  101  with the exterior of the device  100 . During use, air may be drawn into the device  100 , flowing along inlet conduit  103   a  prior to flowing into heating chamber  101 . 
     As is apparent from  FIG. 2 , the width of the inlet conduit  103   a  may be different from, for example less than, the width of the heating chamber  101 . For instance, an average width value of the inlet conduit  103   a  may be less than an average width value of the heating chamber  101 . This may, for example, provide the user with a desirable amount of draw or impedance to flow. 
     The device  100  further includes an outlet conduit  103   b , which fluidically connects the heating chamber  101  with the exterior of the device  100  (and which, in the particular example shown, includes an expansion chamber  144 ). During use, aerosol generated within the heating chamber  101  may flow along outlet conduit  103   b  prior to flowing out of the device  100 . 
     As is apparent from  FIG. 2 , the width of the outlet conduit  103   b  may be different from, for example greater than, the width of the heating chamber  101 . For instance, an average width value of the outlet conduit  103   b  may be greater than an average width value of the heating chamber  101 . This may, for example, allow the aerosol to expand and cool before being inhaled by the user. 
     As also shown in  FIG. 2 , the device  100  includes two heating units  161 ,  162  for heating the aerosol-generating material  110   a . Although the illustrated example includes two heating units  161 ,  162 , it should be understood that this is by no means essential and the device  100  could include only one heating unit, or could include three or more heating units, as appropriate. 
     The inventors have studied the results of tests of devices of similar construction to the device  100  of  FIGS. 1 and 2 . Based on these test results, the inventors foresee a particular risk that condensate collects within conduits that fluidically connect the heating chamber  101  with the exterior of the device, such as inlet conduit  103   a  and outlet conduit  103   b.    
     A possible contributing factor is that, in some cases, unheated portions of the complete path through the device may experience a pressure drop, in comparison to the heated portions, including, in particular, the heating chamber. Therefore, any condensate formed in the device would tend, owing to the pressure differential with the hot heating chamber, to move towards the cooler regions upstream and downstream of the heating chamber, i.e. the inlet and outlet conduits  103   a ,  103   b.    
     A further possible contributing factor is that, in some cases, the device  100  may be designed to offer resistance or impedance to the flow of air into the device, so as to regulate the flow of air through the device  100 ; such resistance/impedance may hinder the exit of condensate-forming substances from the inlet conduit  103   a  and/or outlet conduit  103   b.    
     An additional contributing factor, in the case of the inlet conduit  103   a , is that, in many cases, for condensate-forming substances to exit the inlet conduit  103   a  would involve them travelling in the opposite direction to the flow of air along the inlet conduit  103   a  during use. 
     Without seeking to be bound by this understanding of the contributing factors, the inventors have determined that, by configuring the device  100  so that the interior surface of one or both of the inlet conduit  103   a  and the outlet conduit  103   b  is heated during a session of use, the accumulation of condensate within the conduit(s) in question may be limited and, in some cases, substantially prevented. Such heating of the interior surface of the inlet conduit  103   a  and/or outlet conduit  103   b  may encourage condensate to re-evaporate, assisting the exit of condensate-forming substances from the inlet conduit  103   a  and/or outlet conduit  103   b . Additionally or alternatively, such heating of the interior surface of the inlet conduit  103   a  and/or outlet conduit  103   b  may cause the air within the conduit in question to be heated, thereby increasing the amount of moisture retained by the air and thus reducing the likelihood that condensate forms in the conduit in question. 
     In devices according to one aspect of this disclosure, the heating of the interior surface results in at least a portion of the interior surface attaining a temperature greater than or equal to 85° C. The inventors consider that attaining a temperature of 85° C. for at least a portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 90° C. for at least a portion of the interior surface, in other cases at least 95° C., in still other cases at least 100° C. As may be appreciated, this may encourage condensate to re-evaporate, assisting the exit of condensate-forming substances from the inlet conduit. 
     In devices according to another aspect of this disclosure, the heating of the interior surface results in a middle portion of the interior surface, which is mid-way between first and second ends of the conduit in question, attaining a temperature greater than or equal to 70° C. The temperature of this middle portion is considered to be technically significant, as it may be generally representative of the degree of heating provided by the interior surface to the condensate, as compared with, for example, the temperature of the portion at the end nearest the heating chamber, where the condensate may additionally be heated by residual heat from the heating chamber. The inventors consider that attaining a temperature of at least 70° C. in the middle portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 80° C. in the middle portion of the interior surface, in other cases at least 90° C., in still other cases at least 100° C. 
     As mentioned above, heating of the interior surface of the inlet conduit  103   a  and/or outlet conduit  103   b  may cause the air within the conduit in question to be heated, thereby increasing the amount of moisture retained by the air and thus reducing the likelihood that condensate forms in the conduit in question. The inventors accordingly envisage that, in some devices in accordance with the aspects mentioned above, heating of the interior surface of the inlet conduit  103   a  and/or outlet conduit  103   b  may cause the air within the conduit in question to be heated to a temperature greater than or equal to 120° C. The inventors consider that attaining such an air temperature will, in many cases, be sufficient to materially reduce the likelihood that condensate forms in the conduit in question. Nonetheless, the inventors consider that, in other cases, it may be appropriate to configure the device such that the air is heated to a temperature of greater than or equal to 150° C., or, in still other cases, greater than or equal to 170° C., or, in yet further cases, greater than or equal to 200° C. 
     Returning now to  FIGS. 1 and 2 , it should be noted that, in the particular example device shown, the heating units  161 ,  162  are inductive heating units. Inductive heating units may provide rapid heating of aerosol-generating material. However, the inventors consider such rapid heating may be a risk factor for the accumulation of condensate, for example because inductive heating units may generate condensate-forming substances at a greater rate than they can be carried away. 
     In the particular example device  100  shown in  FIG. 2 , each inductive heating unit  161 ,  162  comprises a respective coil  124 ,  126  and a respective heating element  134 ,  136 . In the particular example shown, the electrically conductive heating elements  134 ,  136  of the two heating units  161 ,  162  correspond to respective sections of a single metal tube  132 . However, in other examples, each heating element may be a separate and distinct structure. More generally, it should be understood that the device may include any suitable number of heating elements for heating the aerosol-generating material; for instance, two, three or more heating elements may be provided. 
     In general, the coil of an inductive heating unit may, for example, be configured to cause heating of one or more electrically-conductive heating elements, for instance so that heat energy is conductible from such electrically-conductive heating elements to aerosol-generating material to thereby cause heating of the aerosol-generating material. An inductive heating unit may be configured to cause the coil to generate a varying magnetic field for penetrating the at least one heating element, to thereby cause induction heating of the at least one heating element. In the device  100  shown in  FIG. 2 , the coil  124 ,  126  of each inductive heating unit  161 ,  162  causes heating of its corresponding electrically-conductive heating element  134 ,  136 . Each heating element  134 ,  136  then conducts heat to the aerosol-generating material  110   a.    
     As will be appreciated, heating units other than induction heating units might be employed in other examples. For instance, the device might include one or more resistive heating units. As an example, a resistive heating unit could be substituted for each of inductive heating units  161 ,  162 . A resistive heating unit may comprise (or consist essentially of) one or more resistive heating elements. By “resistive heating element”, it is meant that on application of a voltage to the element, current flows within the element, with electrical resistance in the element transducing electrical energy into thermal energy which heats the aerosol-generating substrate. A resistive heating element may, for example, be in the form of a resistive wire, mesh, coil and/or a plurality of wires. The heat source may be a thin-film heater. 
     Reference is now directed to  FIG. 3 a    which is close-up view of a cross-section through a modified version  100 ′ of the device  100  of  FIGS. 1 and 2 . In the device  100 ′ shown in  FIG. 3 a   , a portion  1035  of the the interior surface of inlet conduit  103   a  is thermally conductive. Based on experimental testing, the inventors consider that the thermally conductive portion  1035  may suitably have a thermal conductivity greater than 1 W/m/K. For instance, a thermally conductive ceramic, such as zirconia or alumina might be employed. Such thermal conductivity may assist in transferring heat from the heating chamber  101 , by conduction. The transferred heat may then encourage condensate to re-evaporate, assisting the exit of condensate-forming substances from the inlet conduit  103   a.    
     In some cases, the device  100  may be constructed so that the thermally conductive portion&#39;s thermal conductivity is greater than or equal to 5 W/m/K, for example where ceramic materials with higher thermal conductivity (e.g. alumina, or aluminum nitride) are used to form the thermally conductive portion of the interior surface of the inlet conduit  103   a . In some cases, the device  100  may be constructed so that the thermally conductive portion&#39;s thermal conductivity is greater than 10 W/m/K, for example where metallic materials, e.g. metals or alloys, are used to form the thermally conductive portion of the interior surface of inlet conduit  103   a . Illustrative examples of suitable metallic materials include brass, copper, aluminium, and steel, e.g. stainless steel. (It may be noted that most metals and most steels have thermal conductivity greater than 10 W/m/K). In other cases, the device may be constructed so that the thermally conductive portion&#39;s thermal conductivity is greater than 20 W/m/K, or greater than 50 W/m/K, for example, where metallic materials such as brass, copper, aluminium are used. (It may be noted that, for example, aluminium and aluminium alloys typically have a thermal conductivity considerably greater than 100 W/m/K). 
     It should be appreciated that, although  FIG. 3 a    illustrates an example where a portion  1035  of the the interior surface of inlet conduit  103   a  is configured to be thermally conductive, a portion of the interior surface of the outlet conduit  103   b  could be configured to be thermally conductive using essentially the same approach, e.g. by using the materials described above. 
     The device  100 ′ of  FIG. 3 a    may therefore more generally be viewed as an example of a device in which the heating of the interior surface of a conduit during a session of use results, at least in part, from conduction of heat generated by the heating unit. Still more generally, this may be viewed as just one way in which the device may be configured such that the interior surface of a conduit is heated during a session of use. 
     Returning to the particular example illustrated in  FIG. 3 a   , it may be noted that the thermally conductive portion  1035  of the interior surface of inlet conduit  103   a  is conveniently provided by a coating of thermally conductive material on an inlet conduit support  131 . As shown in  FIG. 3 a   , this inlet conduit support  131  may, for example, provide the remainder of the interior surface of the inlet conduit  103   a . In some examples, the inlet conduit support  131  may be made by molding and hence (or otherwise) may suitably be constructed from a moldable polymeric material, such as polyether ether ketone (PEEK). Hence, or otherwise, the inlet conduit support  131  may, in some examples be integrally-formed (for example, being constructed from a single homogenous material); nonetheless, in other examples, the inlet conduit support  131  may comprise plural components and/or may be of composite construction. 
     Furthermore, although the device  100 ′ includes only a single portion of thermally conductive material, coating  1035 , in other examples the device might include plural portions of thermally conductive material, each of which provides a respective portion of the interior surface of conduit  103   a . Different portions of thermally conductive material may comprise different (thermally conductive) materials. 
     It may be noted that, in the particular device  100 ′ shown in  FIG. 3 a   , the distal end of coating  1035  is located proximally of the distal end  1031  of the inlet conduit  103   a . This may, for example, reduce the risk of the user coming into contact with a hot surface of the device. For the same reasons, in devices having multiple portions of thermally conductive material that provide part of the inner surface of inlet conduit  103   a , such portions of thermally conductive material may have their distal ends located proximally of the distal end  1031  of the inlet conduit  103   a.    
     It may also be noted that, in the particular device  100 ′ shown in  FIG. 3 a   , the coating  1035  extends to the proximal end  1032  of the inlet conduit  103   a . This may assist the thermally conductive material of the coating in transferring heat away from the heating chamber  101 , particularly (but not exclusively) where the proximal end of the inlet conduit abuts the distal end of heating chamber  101 , as is the case in  FIG. 3 . In general, in devices having one or more portions of thermally conductive material that provide part of the inner surface of inlet conduit  103   a , at least some of these portions may extend to the proximal end of the inlet conduit so as to assist in heat transfer. 
     Referring once more to  FIG. 3 a   , it may be noted that the particular example device  100 ′ shown includes a number of apertures  141 , each of which opens, on one side, to the distal end  1031  of the inlet conduit  103   a , and, at an opposite side, to the exterior of the device. Accordingly, such apertures  141  may, for example, be described as fluidically connecting the inlet conduit to the exterior of the device. During use of the device, air may flow into the inlet conduit  103   a  through these apertures  141 . Such apertures  141  may provide suitable impedance to the flow of air into the device, so as to regulate the flow of air through the device  100 . However, such impedance may equally increase the risk that condensate collects within the inlet conduit  103   a . Nonetheless, by configuration of the device  100 ′, in accordance with one of the aspects of this disclosure, the accumulation of condensate within the inlet conduit may be limited and, in some cases, substantially prevented. 
     While a coating  1035  is referred to herein, it will of course be appreciated this is merely an example of a layer (and, more particularly, a conformal layer) of thermally conductive material providing the thermally conductive portion  1035  of the interior surface of inlet conduit  103   a . Accordingly, the teaching is not limited to layers formed by coating techniques. As will be understood, there are many techniques for forming a conformal layer of material, such as physical or chemical deposition techniques; as a particular example, plating techniques (e.g. electro-plating) might be used to form a layer of thermally conductive material. 
     Furthermore, while in the device  100 ′ only a portion of the interior surface of inlet conduit  103   a  is thermally conductive, it should be understood that, in other examples, substantially the entirety of the interior surface might be thermally conductive, having a thermal conductivity greater than 1 W/m/K, 5 W/m/K (or 20 W/m/K, or 50 W/m/K, depending on the particular arrangement). Such an example is shown in  FIG. 3 b   , where coating  1035 ′ extends all the way to the distal end  1031  of inlet conduit  103   a.    
     Moreover, it is of course by no means essential that the device includes a conformal layer of thermally conductive material, such as a coating  1035 . Indeed, there are various constructional approaches to providing a thermally conductive portion of the interior surface of inlet conduit  103   a . As one example, the device might include a liner in the inlet conduit  103   a.    
     As a further example, the device might include a tubular/cylindrical component  1036  constructed entirely of thermally conductive material (for example: a metallic material, such as a metal or an alloy, illustrative examples of suitable metallic materials including brass, copper, aluminium, and steel, e.g. stainless steel; or a thermally conductive ceramic material, such as as zirconia or alumina), with the thermally conductive portion of the interior surface of the inlet conduit  103   a  being provided by the tubular component. Such an example is shown in  FIG. 3 c   , where the device includes tubular component  1036 , which defines the entirety of the interior surface of inlet conduit  103   a . In a particular example, the tubular component  1036  might suitably be constructed entirely from metallic materials such as brass, aluminium, steel (e.g. stainless steel), and/or copper. In the particular example shown, the tubular component  1036  has generally the same shape as the inlet conduit support  131  shown in  FIGS. 3 a  and 3 b   , and therefore connects to and supports other components in the device, including the metal tube  132  that provides the two heating elements  134 ,  136 ; however, this is of course not essential, and the tubular component  1036  could have any appropriate shape. 
     A still further example of a construction that provides a thermally conductive portion of an interior surface of an inlet conduit  103   a  is shown in  FIG. 3 d   , where a tubular component  1037  constructed entirely of thermally conductive material (for example: a metallic material, such as a metal or an alloy, illustrative examples of suitable metallic materials including brass, copper, aluminium, and steel, e.g. stainless steel; or a thermally conductive ceramic material, such as as zirconia or alumina), is provided as an insert within another component, which may, for instance, be constructed of thermally insulating materials, such as polymeric materials. In the particular example shown in  FIG. 3 d   , tubular component  1037  is provided as an insert within inlet conduit support  131 , which, as noted above, may be made of moldable polymeric material, such as polyether ether ketone (PEEK). The tubular component  1037  might suitably be constructed entirely from metallic materials such as brass, aluminium, steel (e.g. stainless steel), and/or copper. 
     It should also be understood that any of the approaches described above for providing a thermally conductive portion  1035  of the the interior surface of inlet conduit  103   a  could equally be adopted to provide a thermally conductive portion of the interior surface of outlet conduit  103   b . Thus, outlet conduit  103   b  could, for example, include a coating  1035 , tubular/cylindrical component  1036  and/or tubular insert  1037  as described above. 
     Furthermore, while coating  1035 , tubular/cylindrical component  1036  and tubular insert  1037  have been described as being formed of a thermally conductive material, it should be understood that they could also be formed of an electrically conductive material, such as a metallic material, for example a metal or an alloy. Illustrative examples of suitable metallic materials include brass, copper, aluminium, and steel (e.g. stainless steel). These should more generally be understood as examples of devices in which at least a portion of the interior surface of inlet conduit is formed of electrically conductive material. Furthermore, it should be appreciated that, where such devices include at least one inductive heating unit that heats the device&#39;s heating chamber (such as inductive heating units  161 ,  162  of device  100 ′) the inductive heating unit may also cause the electrically conductive portion of the interior surface of inlet conduit to be inductively heated. Still further, this electrically conductive portion may, in some examples, be formed of ferromagnetic and/or ferrimagnetic material, so as to be additionally be heated as a result of magnetic hysteresis losses. 
     Still more generally, such inductive heating may be viewed as an additional (or alternative) way in which the interior surface of a conduit may be heated during a session of use. 
     With the benefit of the teaching of this disclosure, further ways of heating the interior surface of an inlet or outlet conduit during a session of use should be apparent. For instance, in other examples, one or more dedicated heating units could be provided for heating the interior surface of a conduit. 
     Moreover, in accordance with a further aspect of this disclosure, it is envisaged that a heating unit may be provided that heats the air within an inlet or an outlet conduit. In this regard, reference is directed to  FIG. 4 , which shows a device  100 ″ according to this aspect of this disclosure. In general, the device  100 ″ is a modified version of the device  100  of  FIGS. 1 and 2 . 
     Notably, the device  100 ″ includes an air heating unit  163  for heating air within the inlet conduit  103   a . In accordance with the present aspect of the disclosure, this heating of air within the conduit  103   a  substantially prevents accumulation of condensation within the conduit  103   a . In particular examples, the air is heated to a temperature of greater than or equal to 120° C. The inventors consider that attaining such an air temperature will, in many cases, be sufficient to substantially reduce the likelihood that condensate forms in the conduit in question. Nonetheless, the inventors consider that, in other cases, it may be appropriate to configure the device  100 ″ such that the air is heated to a temperature of greater than or equal to 150° C., or, in still other cases, greater than or equal to 170° C., or, in yet further cases, greater than or equal to 200° C. 
     Although in the example device  100 ″ of  FIG. 4  the heating unit  163  is arranged so as to heat air within the inlet conduit  103   a  of the device  100 ″ it should be understood that, in other examples, a similar heating unit could be provided to heat air within the outlet conduit  103   b . Indeed, in still further embodiments, respective air heating units could be provided for the inlet and outlet conduits  103   a ,  103   b.    
     In the particular example shown in  FIG. 4 , the air heating unit  163  includes a resistive heating element  1034 . Resistive heating elements may be suitable because they are relatively compact. However, devices according to further examples might utilise other types of heating element. 
     As illustrated in  FIG. 4 , the heating element  1034  may, for example, define a portion of the interior surface of the inlet conduit  103   a . However, this is not essential and in other examples other components may define the interior surface of the conduit. In such examples, the heating element might, for instance, be arranged so as to transfer heat to the conduit-defining components by conduction. The conduit-defining components might therefore be constructed from one of the thermally conductive materials discussed above. 
     As is apparent from  FIG. 4 , the heating element  1034  extends circumferentially around inlet conduit  103   a . However, in other examples, the heating element(s) of the heating unit  163  could instead be provided at an end of the conduit  103   a , for example the end furthest from the heating chamber  101 . In such examples, the heating element(s) might be arranged such that air passes through or between the heating element(s) when entering the conduit (in the case of an inlet conduit  103   a ) or when leaving the conduit (in the case of an outlet conduit  103   b ). In a particular example, the heating element(s) could be provided on or in a cap  140  or door that separates the conduit from the exterior of the device. 
     As also shown in  FIG. 4 , the heating element  1034  is spaced from the exterior of the device, for example such that it is inaccessible to the user during use of the device  100 ″. Arranging the heating element(s) of the heating unit  163  such that they are spaced from the exterior of the device may, for example, reduce the risk of the user coming into contact with a hot surface of the device  100 ″. 
     In a number of examples, the air heating unit  163  is controlled separately from the heating unit(s)  161 ,  162  that heat aerosol-generating material within the heating chamber  101  of the device  100 ″. As a result, the air heating unit  163  may be operated at different times to the heating unit(s)  161 ,  162  for the heating chamber  101 . In general, the heating unit(s)  161 ,  162  for the heating chamber  101  may be activated prior to the air heating unit  163  for the conduit  103   a , for example because condensation is not expected to be formed until the aerosol-generating material has been heated for a meaningful period of time. 
     It is further envisaged that the air heating unit  163  may be controlled in dependence upon the output from one or more sensors. The output from the one or more sensors may, in some examples, be provided to a controller, such as a microcontroller, which in turn controls the air heating unit  163  based on such output, or, in other examples, may be provided directly to the air heating unit  163 , which may, for instance include suitable logic circuitry to control the operation of the air heating unit  163 . 
     In one example, the one or more sensors may comprise one or more sensors that sense whether aerosol-generating material is present within the heating chamber  101  used. Such sensors might, for example, include pressure sensors arranged such that any aerosol-generating material present in the chamber applies pressure to them, or optical sensors arranged such that any aerosol-generating material reduces the amount of light reaching the optical sensors. The output from such sensors may be used to control the air heating unit  163  such that it heats air within the conduit (e.g. to above a threshold temperature) in response to the sensor output indicating that aerosol-generating material has been removed from the heating chamber. In such an example, the air heating unit  163  may assist in removing moisture from the device  100 ″ that was generated during a session of use by the user. 
     In another example, the one or more sensors may comprise one or more sensors that sense whether the user is inhaling aerosol generated by the device. Such sensors might, for example, sound sensors (e.g. microphones) or air pressure sensors. The output from such sensors may be used to control the air heating unit  163  such that it heats air within the conduit (e.g. to above a threshold temperature) in response to the sensor output indicating that the user has inhaled aerosol. For example, the air heating unit  163  may achieve the threshold temperature shortly after the user finishes inhaling. Hence, or otherwise, the air heating unit  163  may be operated between puffs by the user. 
     Attention is now directed to  FIG. 5 a   , which shows a device  100 ′″ according to a further aspect of this disclosure, in which a component  1038   a  defining at least a portion of the inlet conduit  103   a  includes a susceptor  1039   a  that is heatable by an inductor  126 . As shown in  FIG. 5 a   , the susceptor  1039   a  may, for example, surround a part of the inlet conduit. 
     In the particular example shown in  FIG. 5 a   , the entirety of component  1038   a  is constructed of the same electrically conductive material. For instance, component  1038   a  might be formed of a metallic material, e.g. a metal or metal alloy. Illustrative examples of suitable metallic materials include brass, copper, aluminium, and steel, e.g. stainless steel. Nonetheless, in other examples, the susceptor  1039   a  could be constructed from different materials as compared with the other parts of the component  1038   a.    
     As shown in  FIG. 5 a   , in some embodiments the susceptor  1039   a  may simply correspond to a proximal portion of component  1038   a  that is surrounded by the inductor  126 . In still other examples, the susceptor  1039   a  might make up substantially the entirety of the component  1038   a . In one such example, the inductor  126  might extend beyond the distal end of inlet conduit-defining component  1038   a , to surround the entirety of component  1038   a , rather than just a proximal portion thereof, as is the case in  FIG. 5   a.    
     It may be noted that, in the particular example shown in  FIG. 5 a   , susceptor  1039   a  abuts susceptor  136 . As a result, susceptor  1039   a  is additionally heated by thermal conduction from susceptor  136 . However, this is not essential and, in other example devices according to the present aspect, susceptor  1039   a  and susceptor  136  could be spaced apart from one another and, indeed, could be thermally insulated from one another. 
     It may further be noted that, as shown in  FIG. 5 a   , the proximal end of component  1038   a  circumferentially surrounds the distal end of the susceptor  136 . This may assist in reliably positioning the susceptor  136  during assembly of the device and/or may provide effective heat conduction from the susceptor to component  1038   a.    
     As also shown in  FIG. 5 a   , the device  100 ′″ may additionally include a support  131  that comprises (or is constructed substantially entirely of) thermally insulating material. For example, support  131  might comprise (or be constructed substantially entirely of) plastic or polymeric material, such as a moldable polymeric material, e.g. polyether ether ketone (PEEK). As is apparent, support  131  includes a passageway that extends between two ends of the support  131 , with component  1038   a  being located within this passageway. 
     As also shown in  FIG. 5 a   , susceptor  1039   a , and component  1038   a  in general, is spaced from the outermost end of the passageway within support  131 . This may, for example, reduce the risk of the user coming into contact with a hot surface of the device. 
     It will further be noted that, in the particular example shown in  FIG. 5 a   , inductor  126  is operable to cause heat to be generated within both susceptor  1039   a  (thereby causing heating of the inlet conduit  103 ) and susceptor  136  (thereby causing heating of heating chamber  101 ). However, it is envisaged that, in some embodiments according to this aspect of the disclosure, the heating chamber  101  might instead be heated by a separate, dedicated heating unit. Thus, for example, a separate inductor could be provided to generate heat within susceptor  136 . Additionally, or alternatively, susceptor  1039   a  might be configured so as to be inherently less susceptible to inductive heating than susceptor  136 . For example, the susceptor  1039   a  might be constructed from a material that is inherently less susceptible to inductive heating than the material from which susceptor  136  is constructed. In one example, susceptor  1039   a  might be constructed from stainless steel and susceptor  136  might be constructed from mild or carbon steel. 
     Moreover, in some embodiments, the heating unit for the heating chamber  101  might not be an inductive heating unit; it could instead be a resistive heating unit, for instance. Therefore, the device could, for example, include a resistive heating element, such as a coil of resistive heating wire, or one or more interconnected conductive tracks provide on a substrate (e.g. forming part of a film heater). 
     More generally, it is envisaged that any of the approaches described above for inductively heating the inlet conduit  103   a  may, additionally or alternatively, be employed to heat an outlet conduit  103   b . In this regard, reference is directed to  FIG. 5 b   , which is a schematic diagram of a device where both an inlet conduit-defining component  1038   a  and an outlet conduit-defining component  1038   b  are inductively heated. While  FIG. 5 b    shows a device in which both an inlet conduit-defining component  1038   a  and an outlet conduit-defining component  1038   b  are inductively heated, it should be understood that the device could equally be configured such that only the outlet conduit-defining component  1038   b  is inductively heated. 
     Referring to  FIG. 5 b   , as may be seen, outlet conduit-defining component  1038   b  includes a portion (or part) that acts as a susceptor  1039   b , so as to be inductively heated by inductor coil  126 . In the particular example shown, inductor coil  126  causes the inductive heating of susceptor  136 , which heats the heating chamber  101  (and any aerosol-generating material within it), the inductive heating of susceptor  1039   b  of outlet conduit-defining component  1038   b , and the inductive heating of susceptor  1039   a  of outlet conduit-defining component  1038   a . However, this is by no means essential and, in other embodiments, respective inductor coils could be provided to cause inductive heating of the inlet conduit-defining component  1038   a  and outlet conduit-defining component  1038   b . Furthermore, as noted above, the heating chamber  101  may also be provided with a dedicated heating unit, which need not be inductive; the heating chamber  101  might, therefore, be heated by one or more resistive heating elements in some embodiments. 
     Still further, in some embodiments one or both of the susceptors  1039   a ,  1039   b  of the conduit-defining components  1038   a ,  1038   b  may be configured so as to be inherently less susceptible to inductive heating than susceptor  136 , which heats the heating chamber  101 . For example, they might be constructed from a material that is inherently less susceptible to inductive heating than the material from which susceptor  136  is constructed. In one example, they might be constructed from stainless steel, while susceptor  136  might be constructed from mild or carbon steel. 
     Still further, in devices according to this aspect of this disclosure, the heating of the susceptor may result in an interior surface of the associated inlet or outlet conduit attaining a temperature greater than or equal to 85° C. As noted above, the inventors consider that attaining a temperature of 85° C. for at least a portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 90° C. for at least a portion of the interior surface, in other cases at least 95° C., in still other cases at least 100° C. 
     Alternatively, or additionally, in devices according to this aspect of this disclosure, the heating of a conduit may result in a middle portion of its interior surface, which is mid-way between first and second ends of the conduit in question, attaining a temperature greater than or equal to 70° C. The temperature of this middle portion is considered to be technically significant, as it may be generally representative of the degree of heating provided by the interior surface to the condensate, as compared with, for example, the temperature of the portion at the end nearest the heating chamber, where the condensate may additionally be heated by residual heat from the heating chamber. The inventors consider that attaining a temperature of at least 70° C. in the middle portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 80° C. in the middle portion of the interior surface, in other cases at least 90° C., in still other cases at least 100° C. 
     Returning to  FIG. 5 b   , it may be noted that the width of the heating chamber  101  is substantially constant over its length. Thus, the heating chamber&#39;s width w 2  at is distal end is substantially the same as its width w 3  at its proximal end and its width w 1  at its middle. However, this is not essential. In other examples, the width of the chamber may increase from its middle towards its proximal and/or distal ends (e.g. so that the chamber is hourglass-shaped). Particularly (but not exclusively) where the heating elements for the chamber surround or define the chamber, the greater width of the proximal and distal end portions of the chamber may result in the proximal and/or distal ends of the smoking article receiving less heating. Reduced heating of the end portions of the article and, in particular, the end portions of the aerosol-generating material within the article, may result in those end portions acting to collect and/or absorb condensation. In addition, reduced heating of the proximal end of the article may be particularly appropriate where the article includes a filter at its proximal end, as it may reduce the risk of damage to the filter. 
     It should be noted that the inventors view the device  100 ′″ of  FIG. 5 a    and the device  100 ′″ of  FIG. 5 b    as embodying a further aspect of this disclosure, which will now be described. 
     As may be seen from  FIG. 5 a   , component  1038   a , which defines at least a portion of the inlet conduit  103   a  of the device  100 ′″, abuts susceptor  136 . It may therefore be understood that, where this component  1038   a  comprises thermally conductive material it may be heated by thermal conduction from the susceptor  136 . This may in turn cause heating of inlet conduit  103   a , thereby assisting in preventing accumulation of condensation within the inlet conduit  103   a.    
     In the device of  FIG. 5 b   , both inlet conduit-defining component  1038   a  and outlet conduit-defining component  1038   b  abut susceptor  136 . Thus, where components  1038   a  and  1038   b  comprise thermally conductive material, they may each be heated by thermal conduction from the susceptor  136 , in turn causing heating of inlet conduit  103   a  and outlet conduit  103   b.    
     According to the present aspect it is envisaged that such conducted heat may be used to heat inlet conduit  103   a  and/or outlet conduit  103   b  and to thereby prevent accumulation of condensation within the associated conduit(s)  103   a ,  103   b , without it being necessary for the corresponding conduit-defining component(s)  1038   a ,  1038   b  to include any part that is inductively heated, such as susceptor  1039   a . Furthermore, given that such inductive heating is optional in this aspect of the disclosure, the inventors envisage that the corresponding conduit-defining components  1038   a ,  1038   b  may abut a non-inductive heating element. Thus, in devices according to the present aspect, a conduit-defining component  1038   a ,  1038   b  might, for example, abut a resistive heating element, rather than abutting susceptor  136 , as is shown in  FIG. 5 . 
     In the embodiment shown in  FIG. 5 a   , component  1038   a  and susceptor  136  not only abut, but are also “keyed”, being rotationally locked or interlinked. Nonetheless, in other embodiments, they might be fixed to one another other to prevent relative movement in general, such as by soldering, welding, brazing, adhesion, mechanical-interlinking or otherwise. 
     In some embodiments, the thermally conductive material of a conduit-defining component may have a thermal conductivity of greater than or equal to 1 W/m/K, for instance where a thermally conductive ceramic, such as zirconia or alumina is employed. In other embodiments, the thermally conductive material may have a thermal conductivity of greater than or equal to 5 W/m/K, for example where ceramic materials with higher thermal conductivity (e.g. alumina, or aluminum nitride) are used. In still other embodiments, the thermally conductive material may have a thermal conductivity of greater than 10 W/m/K, for example where metallic materials, e.g. metals or alloys, are used. Illustrative examples of suitable metallic materials include brass, copper, aluminium, and steel, e.g. stainless steel. (It may be noted that most metals and most steels have thermal conductivity greater than 10 W/m/K). In still other embodiments, the thermally conductive material may have a thermal conductivity of greater than 20 W/m/K, or greater than 50 W/m/K, for example, where metallic materials such as brass, copper, aluminium are used. (It may be noted that, for example, aluminium and aluminium alloys typically have a thermal conductivity considerably greater than 100 W/m/K). 
     In some embodiments, substantially the entirety of a conduit-defining component  1038   a ,  1038   b  might be constructed from thermally conductive material as described above. 
     In devices according to this aspect of this disclosure, the heating of an inlet and/or outlet conduit may result in an interior surface of the conduit(s) in question attaining a temperature greater than or equal to 85° C. As noted above, the inventors consider that attaining a temperature of 85° C. for at least a portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 90° C. for at least a portion of the interior surface, in other cases at least 95° C., in still other cases at least 100° C. 
     Alternatively, or additionally, in devices according to this aspect of this disclosure, the heating of an inlet and/or outlet conduit may result in a middle portion of the interior surface of the conduit(s) in question attaining a temperature greater than or equal to 70° C. (the middle portion of a conduit being defined as the portion mid-way between first and second ends of that conduit.) The temperature of this middle portion is considered to be technically significant, as it may be generally representative of the degree of heating provided by the interior surface to any condensate, as compared with, for example, the temperature of the portion at the end nearest the heating chamber, where the condensate may additionally be heated by residual heat from the heating chamber. The inventors consider that attaining a temperature of at least 70° C. in the middle portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 80° C. in the middle portion of the interior surface, in other cases at least 90° C., in still other cases at least 100° C. 
     Although  FIG. 5 a    shows inlet conduit-defining component  1038   a  and susceptor  136  as being rotationally locked or interlinked, they may instead, as mentioned above, be fixed to one another other to prevent relative movement in general. For example, they may be fixed together by soldering, welding, brazing, adhesion, mechanical attachment (e.g. crimping or push-fitting) or mechanical interlinking. In accordance with yet another aspect of this disclosure, it is envisaged that inlet conduit-defining component  1038   a  and susceptor  136  may be sealingly joined to one another (e.g. by welding, soldering, brazing, adhesive or mechanical attachment), such that a hermetic seal is provided where the heating chamber  101  and the inlet conduit  103   a  meet. Some embodiments may be described as providing a hermetic seal in the vicinity of a confluence or junction of the heating chamber  101  with the inlet conduit  103   a.    
     Indeed, the same approach may be employed with respect to an outlet conduit-defining component  1038   b . For example, outlet conduit-defining component  1038   b  in  FIG. 5 b    may be sealingly joined to susceptor  136  such that a hermetic seal is provided where the heating chamber  101  and the outlet conduit  103   b  meet. Some embodiments may be described as providing a hermetic seal in the vicinity of a confluence or junction of the heating chamber  101  with the outlet conduit  103   b.    
     It is considered that there is a particular risk of escape of condensate-forming substances where the heating chamber meets an inlet or an outlet conduit. Such substances could contaminate the space between the heating chamber  101  and an insulating member  128  (described below) that is radially outwards of the heating chamber  101 , for example. Such a hermetic seal significantly reduces this risk. 
     Reference is now directed to  FIG. 6 a   , which shows a device  100  according to an embodiment of this aspect of the disclosure. As may be seen, the device  100  includes a susceptor  136 , which is welded or brazed to inlet conduit-defining component  1038   a  at one end (as indicated by emboldened lines  1033   a ) and is welded or brazed to outlet conduit-defining component  1038   b  at the other end (as indicated by emboldened lines  1033   b ). As may be seen, the welding/brazing  1033   a ,  1033   b  has taken place about an exterior of the susceptor  136  and the conduit-defining components  1038   a ,  1038   b . This avoids the welding or brazing impacting upon the shape of the interior passageway that comprises heating chamber  101  and inlet and outlet conduits  103   a ,  103   b . However, in other embodiments, the welding or brazing could take place on the interior in addition to, or instead of, the exterior. 
     In some embodiments, at least a portion of the inlet conduit-defining component  1038   a  and/or the outlet conduit-defining component  1038   b  comprises (or is formed of) thermally conductive material. 
     In some embodiments, the thermally conductive material of a conduit-defining component may have a thermal conductivity of greater than or equal to 1 W/m/K, for instance where a thermally conductive ceramic, such as zirconia or alumina is employed. In other embodiments, the thermally conductive material may have a thermal conductivity of greater than or equal to 5 W/m/K, for example where ceramic materials with higher thermal conductivity (e.g. alumina, or aluminum nitride) are used. In still other embodiments, the thermally conductive material may have a thermal conductivity of greater than 10 W/m/K, for example where metallic materials, e.g. metals or alloys, are used. Illustrative examples of suitable metallic materials include brass, copper, aluminium, and steel, e.g. stainless steel. (It may be noted that most metals and most steels have thermal conductivity greater than 10 W/m/K). In still other embodiments, the thermally conductive material may have a thermal conductivity of greater than 20 W/m/K, or greater than 50 W/m/K, for example, where metallic materials such as brass, copper, aluminium are used. (It may be noted that, for example, aluminium and aluminium alloys typically have a thermal conductivity considerably greater than 100 W/m/K). 
     In some embodiments, substantially the entirety of a conduit-defining component  1038   a ,  1038   b  might be constructed from thermally conductive material as described above. In other embodiments, only a portion of the interior surface of the inlet and/or outlet conduit-defining components  1038   a , 1038   b  may be constructed from thermally conductive material. 
     Although heating chamber  101  is defined by susceptor  136  in the embodiment of  FIG. 6 a   , this is by no means essential and in other embodiments the heating chamber  101  could be defined by one or more components, none of which acts as a susceptor. For instance, the components defining the heating chamber  101  might include a thermally conductive component (such as a tube formed of thermally-conductive material) upon which one or more resistive heating elements are mounted. 
     In the particular embodiment shown in  FIG. 6 a   , the inlet conduit-defining component  1038   a  and the outlet conduit-defining component  1038   b  each act as a susceptor and are heatable by the same inductor  126  that causes the heating of susceptor  136 . However, in other embodiments, such as that shown in  FIG. 6 b   , each of inlet conduit-defining component  1038   a  and outlet conduit-defining component  1038   b  may be heatable by a respective, dedicated inductor  127   a ,  127   b . In such a case, the device may be configured to individually control the heating of inlet conduit-defining component  1038   a  and outlet conduit-defining component  1038   b.    
     In still other embodiments, multiple inductors may be provided for causing the heating of respective portions of the susceptor  136 . For instance, multiple inductors may cause the heating of respective lengthwise portions of a susceptor  136 , as is the case in the device shown in  FIG. 2 , which includes inductors  124  and  126 . In some embodiments where multiple inductors are provided, a first inductor (or a first group of inductors) may be arranged to cause the heating of a portion of a susceptor that defines the heating chamber, as well as a portion of a susceptor that defines one of the inlet or outlet conduits. By contrast, a second inductor (or a second group of inductors) may be arranged to cause the heating of a different portion of the susceptor that defines the heating chamber, as well as a portion of a susceptor that defines the other of the inlet and outlet conduits. 
     Still further approaches of configuring the aerosol provision device so that the interior surface of a conduit is heated during a session of use will be apparent from the discussion further above. For instance, heat may be transferred by thermal conduction from the heating element (e.g. susceptor  136 ) for the heating chamber  101 . Accordingly, it will be understood that it is by no means essential that inlet conduit-defining component  1038   a  and outlet conduit-defining component  1038   b  act as susceptors. 
     It should be understood that sealingly joining components that define a heating chamber to components that define an inlet or outlet conduit is considered just one approach for providing a hermetic seal where a heating chamber meets an inlet or outlet conduit. An alternative approach is illustrated in  FIG. 6 c   , which shows a device which includes a unitary, or integrally-formed component  1011  that defines a heating chamber  101 , an inlet conduit  103   a  and an outlet conduit  103   b . As shown, a continuous passageway or lumen may extend through the unitary component  1011 . In the embodiment shown, this passageway includes heating chamber  101 , inlet conduit  103   a  and outlet conduit  103   b . In some embodiments, this entire passageway may be hermetically sealed, so as to substantially inhibit the escape of condensate-forming substances, except from, for example, the longitudinal ends of the passageway. 
     Although such a passageway that is sealed along substantially its entire length is described with reference to an embodiment including a unitary component, it should be understood that such a substantially sealed passageway may equally be present in embodiments such as those shown in  FIGS. 6 a  and 6 b    where multiple components define a heating chamber and inlet and/or outlet conduits. 
     Returning to the embodiment of  FIG. 6 c   , it should be appreciated that the unitary component  1011  may be formed by a variety of suitable processes. For example, the unitary component  1011  may—particularly where the unitary component  1011  is formed of a metal or an alloy—be formed in a spin forming or flow forming process. In other examples, the unitary component  1011  may be formed by an additive manufacturing/3D printing process, by extrusion, or by casting. 
     In the particular embodiment shown in  FIG. 6 c   , a first portion  1361  of the integrally-formed component  1011  defines the heating chamber  101  and acts as a first susceptor, which heats aerosol-generating material within the heating chamber  101 . Second and third portions  1362 ,  1363  of the integrally-formed component  1011  define, respectively inlet conduit  103   a  and outlet conduit  103   b  and are inductively heatable by the same inductor  126  that causes inductive heating of the first portion  1361 . 
     However, in other embodiments, such as that shown in  FIG. 6 d   , second and third portions  1362 ,  1363  of the integrally-formed component  1011  may be heatable by a respective inductor  127   a ,  127   b . In such a case, the device may be configured to individually control the heating of inlet conduit-defining component  1038   a  and outlet conduit-defining component  1038   b.    
     While in the embodiments of  FIGS. 6 c  and 6 d    the same integrally-formed component  1011  defines heating chamber  101 , inlet conduit  103   a  and outlet conduit  103   b , in other embodiments an integrally-formed component might instead define just heating chamber  101  and inlet conduit  103   a , or just heating chamber  101  and outlet conduit  103   b . In such a case, one or more separate components may define the outlet conduit  103   b  or inlet conduit  103   a  respectively, with those components for example being sealingly joined to the unitary component, for instance by welding (e.g. as described above) soldering, brazing, or adhesive. 
     In devices according to this aspect of this disclosure, the heating of an inlet and/or outlet conduit may result in an interior surface of the conduit(s) in question attaining a temperature greater than or equal to 85° C. As noted above, the inventors consider that attaining a temperature of 85° C. for at least a portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 90° C. for at least a portion of the interior surface, in other cases at least 95° C., in still other cases at least 100° C. 
     Alternatively, or additionally, in devices according to this aspect of this disclosure, the heating of an inlet and/or outlet conduit may result in a middle portion of the interior surface of the conduit(s) in question attaining a temperature greater than or equal to 70° C. (the middle portion of a conduit being defined as the portion mid-way between first and second ends of that conduit.) The temperature of this middle portion is considered to be technically significant, as it may be generally representative of the degree of heating provided by the interior surface to any condensate, as compared with, for example, the temperature of the portion at the end nearest the heating chamber, where the condensate may additionally be heated by residual heat from the heating chamber. The inventors consider that attaining a temperature of at least 70° C. in the middle portion of the interior surface will in many cases be sufficient to cause significant re-evaporation of condensate. Nonetheless, in some cases, the device may be configured to attain a temperature of at least 80° C. in the middle portion of the interior surface, in other cases at least 90° C., in still other cases at least 100° C. 
     Reference is now directed to  FIG. 7 a   , which shows a device  100 ″″ according to a still further aspect of this disclosure. Similarly to the devices shown in  FIGS. 1-5   d,  the device  100 ″″ of  FIG. 7 a    is configured to receive an article  110  comprising aerosol-generating material and the device  100 ″″ is configured to generate aerosol from the aerosol-generating material  1105  when the article  110  is received within the device  100 ″″. The device  100 ″″ accordingly includes a heating assembly for heating the aerosol-generating material  1105  during a session of use. The heating assembly includes at least one heating element, such as a susceptor  136 , as in shown in  FIG. 7   a.    
     The device of  FIG. 7 a    further includes a stop  105 . Stop  105  prevents a distal end of the article  110  from moving distally beyond a limit position when the article  110  is inserted in the aerosol provision device. As may be seen, in the particular example shown in  FIG. 7 , stop  105  defines a limit position that is located distally of the distal end of the susceptor  136 . By contrast, in the devices shown in  FIGS. 1-5b , the stop  105  defines a limit position at the distal end of the susceptor  136 . 
     As may be appreciated, as a result of the limit position being located distally of the distal end of the susceptor  136 , there is a portion of the length of the aerosol-generating material  1105  within the smoking article that, when the article  110  is fully inserted in the device, does not overlap with any heating element. This portion extends proximally by a first distance  151  from the distal end  1101  of the aerosol-generating material  1105 . The inventors consider that this portion, which is heated to a significantly lesser degree than other parts of the aerosol-generating material  1105 , may act to collect and/or absorb condensation, which might otherwise build up within the device, for instance within inlet or outlet conduits. 
     In the particular example shown in  FIG. 7 a   , the stop  105  comprises an annular surface. However, it could instead comprise an array of circumferentially spaced protrusions, or any suitable structure. 
     In many cases, stop  105  will be aligned with the opening  104  in the device  100  through which article  110  is inserted (and also with the article receiving chamber  101 ). Furthermore, the stop  105  may have a minimum internal diameter that is smaller (for example by 2 mm or more) than a minimum internal diameter of the opening  104 , so that, while the article may move freely through the opening  104 , its movement is blocked by stop  105 . 
     It may also be noted that in the particular embodiment shown in  FIG. 7 a   , the distal end of the susceptor  136  is flared outwardly. In some embodiments, this flared distal end may have an extent of 2 mm or less in the length direction of the susceptor. A flared distal end may assist in reliably positioning the susceptor  136  during assembly of the device. For example, as shown in  FIG. 7 a   , the flared distal end may engage with (or abut with) an abutment  1315 . In the particular example shown in  FIG. 7 a   , the abutment  1315  comprises an annular surface. However, it could instead comprise an array of circumferentially spaced protrusions, or any suitable structure. 
     In the particular example shown in  FIG. 7 a   , abutment  1315  is provided by component  1038 , which defines inlet conduit  103   a  (at least in part). Thus, in the example shown in  FIG. 7 a   , component  1038  provides both stop  105  and abutment  1315 . Nonetheless, this is merely an illustrative arrangement and abutment  1315  could be provided by any suitable component of the device  1 . 
     As may be seen from  FIG. 7 a   , the device  100 ″″ includes an article-receiving or heating chamber  1010  and an inlet conduit  103   a . As is apparent, the width of the inlet conduit  103   a  is smaller than the width of the article-receiving chamber  1010 ; this may, for example, provide the user with a desirable amount of draw or impedance to flow. 
     As may also be seen from  FIG. 7 a   , a distal portion  1015  of the article-receiving chamber  1010 , which extends from the distal end of susceptor  136  (or, more generally, from the distal end of the distalmost heating element, where the device  100 ″″ has several heating elements) has a width that is greater than or equal to a portion of the article-receiving chamber  1010  that is located proximally. Such an arrangement may assist the insertion of the article into the distal portion  1015  of the article-receiving chamber. 
     As shown in  FIG. 7 a   , the distal portion  1015  of the article-receiving chamber  1010  may be separated from inlet conduit  103   a  by stop  105 . In the particular example shown, stop  105  is provided at the juncture of the distal portion  1015  of article-receiving chamber  1010  and inlet conduit  103   a.    
     In some embodiments, the distal portion  1015  of the article-receiving chamber  1010  may be defined by thermally insulating material. This may further assist in reducing the amount of heat applied to the distal portion of the smoking article. Suitably, the thermally insulating material may be a plastic, for example polyether ether ketone. 
     It should be understood that, while a susceptor  136  is employed as a heating element in the device  100 ″″ of  FIG. 7 a   , the present aspect is not so limited. Indeed, it is considered that various different types of heating element might be utilised, depending on the particular application. For example, susceptor  136  might be replaced by a resistive heating element, such as a resistive wire coil, or one or more interconnected conductive tracks provided on a substrate (e.g. forming part of a film heater). 
     Furthermore, the inventors envisage that it may be appropriate to additionally (or alternatively) provide an unheated portion at the proximal end  1102  of the aerosol-generating material  1105  within the smoking article  110 . 
     To illustrate the broad scope of this aspect of the disclosure, reference is directed to  FIG. 7 b   , which is a schematic diagram showing a smoking article  110  fully inserted into a device according to a further embodiment of this aspect of the disclosure. For ease of explanation, the device shown in  FIG. 7 b    includes only a single heating element  1200 , which is shown schematically; however, it will be understood that the device could include two, three or more heating elements, depending on the particular application. 
     As is apparent,  FIG. 7 b    shows the article  110  fully inserted into the device, with the distal end  111  of the article  110  at the limit position defined by stop  105 . 
       FIG. 7 b    further shows the aerosol-generating material  1105  within the article  110 . The length of the aerosol-generating material  1105  is indicated in  FIG. 8  by double-headed arrow  1005 . 
     As illustrated in  FIG. 7 b   , in some embodiments, the distal end  111  of the article  110  may be defined by the distal end  1101  of the aerosol-generating material  1105 . As also illustrated in  FIG. 7 b   , the aerosol-generating material  1105  may be in the form of an elongate body, for example a cylindrical body. It may be further noted that, in the particular example shown in  FIG. 7 b   , the article  110  includes a filter  1106 , which extends from the proximal end  1102  of the aerosol-generating material  1105 . 
     As shown in  FIG. 7 b   , when the article  110  is in the fully inserted position, there is a first portion of the length of the aerosol-generating material  1105 , which extends a first distance  1001  proximally from the distal end  1101  of the aerosol-generating material  1105 , that does not overlap with any heating element. 
     As also shown in  FIG. 7 b   , there is, in addition, a second portion of the length of the aerosol-generating material  1105 , which extends a second distance  1002  distally from the proximal end  1102  of the aerosol-generating material  1105 , that likewise does not overlap with any heating element. 
     The first and second portions of the article may each act to collect and/or absorb condensation, which might otherwise build up within the device, for instance within inlet or outlet conduits. 
     The first distance  1001  may, for example, be greater than or equal to 2 mm and less than or equal to 10 mm. In certain cases it may be greater than or equal to 3 mm and less than or equal to 7 mm. In other cases it may be about 5 mm. Likewise, the second distance  1002  may, for example, be greater than or equal to 2 mm and less than or equal to 10 mm. In certain cases, it may be greater than or equal to 3 mm and less than or equal to 7 mm. In other cases it may be about 5 mm. In some cases, the first and second distances  1001 ,  1002  may be substantially equal. 
     Although  FIG. 7 b    shows a device where neither the first portion  1001  nor the second portion  1002  of the length of the aerosol-generating material  1105  overlaps with any heating element, it should be understood that, in other embodiments, the device may be configured such that only the second portion of the length of the aerosol-generating material  1105  does not overlap with any heating element. (Such embodiments will therefore have at least one heating element that overlaps with the proximal end of the aerosol-generating material  1105 .) 
     Reference is next directed to  FIGS. 8-11B , which illustrate various features of the construction and operation of the devices of  FIGS. 1-3 . Similar features may also be employed in the devices of  FIGS. 5 a   - 7   b.    
     Turning first to  FIG. 8 , as shown, the device  100  may comprise a first end member  106  which comprises a lid  108  which is moveable relative to the first end member  106  to close the opening  104  when no article  110  is in place. In  FIG. 1 , the lid  108  is shown in an open configuration, however the lid  108  may move into a closed configuration. For example, a user may cause the lid  108  to slide in the direction of arrow “A”. 
     The device  100  may also include a user-operable control element  112 , such as a button or switch, which operates the device  100  when pressed. For example, a user may turn on the device  100  by operating the switch  112 . 
     The device  100  may also comprise an electrical component, such as a socket/port  114 , which can receive a cable to charge a battery of the device  100 . For example, the socket  114  may be a charging port, such as a USB charging port. 
       FIG. 8  depicts the device  100  of  FIG. 1  with the outer cover  102  removed and without an article  110  present. The device  100  defines a longitudinal axis  180 . 
     As shown in  FIG. 8 , the first end member  106  is arranged at one end of the device  100  and a second end member  116  is arranged at an opposite end of the device  100 . The first and second end members  106 ,  116  together at least partially define end surfaces of the device  100 . For example, the bottom surface of the second end member  116  at least partially defines a bottom surface of the device  100 . Edges of the outer cover  102  may also define a portion of the end surfaces. In this example, the lid  108  also defines a portion of a top surface of the device  100 . 
     The end of the device closest to the opening  104  may be known as the proximal end (or mouth end) of the device  100  because, in use, it is closest to the mouth of the user. In use, a user inserts an article  110  into the opening  104 , operates the user control  112  to begin heating the aerosol generating material and draws on the aerosol generated in the device. This causes the aerosol to flow through the device  100  along a flow path towards the proximal end of the device  100 . 
     The other end of the device furthest away from the opening  104  may be known as the distal end of the device  100  because, in use, it is the end furthest away from the mouth of the user. As a user draws on the aerosol generated in the device, the aerosol flows away from the distal end of the device  100 . 
     The device  100  may further comprise a power source  118 . The power source  118  may be, for example, a battery, such as a rechargeable battery or a non-rechargeable battery. Examples of suitable batteries include, for example, a lithium battery (such as a lithium-ion battery), a nickel battery (such as a nickel-cadmium battery), and an alkaline battery. The battery is electrically coupled to the heating assembly to supply electrical power when required and under control of a controller (not shown) to heat the aerosol generating material. In this example, the battery is connected to a central support  120  which holds the battery  118  in place. 
     The device may further comprise at least one electronics module  122 . The electronics module  122  may comprise, for example, a printed circuit board (PCB). The PCB  122  may support at least one controller, such as a processor, and memory. The PCB  122  may also comprise one or more electrical tracks to electrically connect together various electronic components of the device  100 . For example, the battery terminals may be electrically connected to the PCB  122  so that power can be distributed throughout the device  100 . The socket  114  may also be electrically coupled to the battery via the electrical tracks. 
     As noted above, in the example device  100 , the heating assembly is an inductive heating assembly and comprises various components to heat the aerosol generating material  110   a  via an inductive heating process. Induction heating is a process of heating an electrically conducting object (such as a susceptor) by electromagnetic induction. An induction heating assembly may comprise an inductive element, for example, one or more inductor coils, and a device for passing a varying electric current, such as an alternating electric current, through the inductive element. The varying electric current in the inductive element produces a varying magnetic field. The varying magnetic field penetrates a susceptor suitably positioned with respect to the inductive element, and generates eddy currents inside the susceptor. The susceptor has electrical resistance to the eddy currents, and hence the flow of the eddy currents against this resistance causes the susceptor to be heated by Joule heating. In cases where the susceptor comprises ferromagnetic material such as iron, nickel or cobalt, heat may also be generated by magnetic hysteresis losses in the susceptor, i.e. by the varying orientation of magnetic dipoles in the magnetic material as a result of their alignment with the varying magnetic field. In inductive heating, as compared to heating by conduction for example, heat is generated inside the susceptor, allowing for rapid heating. Further, there need not be any physical contact between the inductive heater and the susceptor, allowing for enhanced freedom in construction and application. 
     The induction heating assembly of the example device  100  comprises a susceptor arrangement  132  (herein referred to as “a susceptor”), a first inductor coil  124  and a second inductor coil  126 . The first and second inductor coils  124 ,  126  are made from an electrically conducting material. In this example, the first and second inductor coils  124 ,  126  are made from Litz wire/cable which is wound in a helical fashion to provide helical inductor coils  124 ,  126 . Litz wire comprises a plurality of individual wires which are individually insulated and are twisted together to form a single wire. Litz wires are designed to reduce the skin effect losses in a conductor. In the example device  100 , the first and second inductor coils  124 ,  126  are made from copper Litz wire which has a rectangular cross section. In other examples the Litz wire can have other shape cross sections, such as circular. 
     The first inductor coil  124  is configured to generate a first varying magnetic field for heating a first section  134  of the susceptor  132  and the second inductor coil  126  is configured to generate a second varying magnetic field for heating a second section  136  of the susceptor  132 . Thus, as discussed above with reference to  FIG. 2 , first inductor coil  124  and first section  134  of susceptor  132  may be considered part of a first heating unit  161 , in which first section  134  of susceptor  132  acts as a heating element, generating heat that is transferred to the aerosol-generating material. By contrast, second inductor coil  126  and second section  136  of susceptor  132  may be considered part of a second heating unit  162 , in which second section  136  of susceptor  132  acts as a heating element, generating heat that is transferred to the aerosol-generating material. 
     In the example shown in  FIG. 8 , the first inductor coil  124  is adjacent to the second inductor coil  126  in a direction along the longitudinal axis  180  of the device  100  (that is, the first and second inductor coils  124 ,  126  to not overlap). The susceptor arrangement  132  may comprise a single susceptor, or two or more separate susceptors. Ends  130  of the first and second inductor coils  124 ,  126  can be connected to the PCB  122 . 
     It will be appreciated that the first and second inductor coils  124 ,  126 , in some examples, may have at least one characteristic different from each other. For example, the first inductor coil  124  may have at least one characteristic different from the second inductor coil  126 . More specifically, in one example, the first inductor coil  124  may have a different value of inductance than the second inductor coil  126 . In  FIG. 10 , the first and second inductor coils  124 ,  126  are of different lengths such that the first inductor coil  124  is wound over a smaller section of the susceptor  132  than the second inductor coil  126 . Thus, the first inductor coil  124  may comprise a different number of turns than the second inductor coil  126  (assuming that the spacing between individual turns is substantially the same). In yet another example, the first inductor coil  124  may be made from a different material to the second inductor coil  126 . In some examples, the first and second inductor coils  124 ,  126  may be substantially identical. 
     In this example, the first inductor coil  124  and the second inductor coil  126  are wound in opposite directions. This can be useful when the inductor coils are active at different times. For example, initially, the first inductor coil  124  may be operating to heat a first section/portion of the article  110 , and at a later time, the second inductor coil  126  may be operating to heat a second section/portion of the article  110 . Winding the coils in opposite directions helps reduce the current induced in the inactive coil when used in conjunction with a particular type of control circuit. In  FIG. 8 , the first inductor coil  124  is a right-hand helix and the second inductor coil  126  is a left-hand helix. However, in another embodiment, the inductor coils  124 ,  126  may be wound in the same direction, or the first inductor coil  124  may be a left-hand helix and the second inductor coil  126  may be a right-hand helix. 
     The susceptor  132  of this example is hollow and therefore defines a heating chamber  101  within which aerosol generating material is received. For example, the article  110  can be inserted into the susceptor  132 . In this example the susceptor  120  is tubular, with a circular cross section. 
     The susceptor  132  may be made from one or more materials. In one example, the susceptor  132  comprises carbon steel having a coating of Nickel or Cobalt. 
     In some examples, the susceptor  132  may comprise at least two materials capable of being heated at two different frequencies for selective aerosolization of the at least two materials. For example, a first section of the susceptor  132  (which is heated by the first inductor coil  124 ) may comprise a first material, and a second section of the susceptor  132  which is heated by the second inductor coil  126  may comprise a second, different material. In another example, the first section may comprise first and second materials, where the first and second materials can be heated differently based upon operation of the first inductor coil  124 . The first and second materials may be adjacent along an axis defined by the susceptor  132 , or may form different layers within the susceptor  132 . Similarly, the second section may comprise third and fourth materials, where the third and fourth materials can be heated differently based upon operation of the second inductor coil  126 . The third and fourth materials may be adjacent along an axis defined by the susceptor  132 , or may form different layers within the susceptor  132 . Third material may the same as the first material, and the fourth material may be the same as the second material, for example. Alternatively, each of the materials may be different. The susceptor may comprise carbon steel or aluminium for example. 
     The device  100  of  FIG. 8  further comprises an insulating member  128  which may be generally tubular and at least partially surround the susceptor  132 . The insulating member  128  may be constructed from any insulating material, such as plastic for example. In this particular example, the insulating member is constructed from polyether ether ketone (PEEK). The insulating member  128  may help insulate the various components of the device  100  from the heat generated in the susceptor  132 . 
     The insulating member  128  can also fully or partially support the first and second inductor coils  124 ,  126 . For example, as shown in  FIG. 8 , the first and second inductor coils  124 ,  126  are positioned around the insulating member  128  and are in contact with a radially outward surface of the insulating member  128 . In some examples the insulating member  128  does not abut the first and second inductor coils  124 ,  126 . For example, a small gap may be present between the outer surface of the insulating member  128  and the inner surface of the first and second inductor coils  124 ,  126 . 
     In a specific example, the susceptor  132 , the insulating member  128 , and the first and second inductor coils  124 ,  126  are coaxial around a central longitudinal axis of the susceptor  132 . 
       FIG. 9  shows a side view of device  100  in partial cross-section. The outer cover  102  is present in this example. The rectangular cross-sectional shape of the first and second inductor coils  124 ,  126  is more clearly visible. 
     The device  100  further comprises inlet conduit support  131  which, in the particular example illustrated, engages one end of the susceptor tube  132  to hold the susceptor tube  132  in place. The inlet conduit support  131  is connected to the second end member  116 . 
     The device may also comprise a second printed circuit board  138  associated within the control element  112 . 
     The device  100  further comprises a second lid/cap  140  and a spring  142 , arranged towards the distal end of the device  100 . The spring  142  allows the second lid  140  to be opened, to provide access to the susceptor tube  132 . A user may open the second lid  140  to clean the susceptor tube  132  and/or the interior surface of inlet conduit  103   a.    
     The device  100  further comprises an expansion chamber  144  which extends away from a proximal end of the susceptor  132  towards the opening  104  of the device. As noted above, expansion chamber  144  forms part of the outlet conduit  103   b  in the example device  1  shown in  FIGS. 1 and 2 . Located at least partially within the expansion chamber  144  is a retention clip  146  to abut and hold the article  110  when received within the device  100 . The expansion chamber  144  is connected to the end member  106 . 
       FIG. 10  is an exploded view of the device  100  of  FIG. 1 , with the outer cover  102  omitted. 
       FIG. 11A  depicts a cross-section of a portion of the device  100  of  FIG. 8 .  FIG. 11B  depicts a close-up of a region of  FIG. 11A .  FIGS. 11A and 11B  show the article  110  received within the susceptor  132 , where the article  110  is dimensioned so that the outer surface of the article  110  abuts the inner surface of the susceptor  132 . This ensures that the heating is most efficient. The article  110  of this example comprises aerosol-generating material  110   a . The aerosol-generating material  110   a  is positioned within the susceptor  132 . The article  110  may also comprise other components such as a filter, wrapping materials and/or a cooling structure. 
       FIG. 11B  shows that the outer surface of the susceptor  132  is spaced apart from the inner surface of the inductor coils  124 ,  126  by a distance  150 , measured in a direction perpendicular to a longitudinal axis  158  of the susceptor  132 . In one particular example, the distance  150  is about 3 mm to 4 mm, about 3-3.5 mm, or about 3.25 mm. 
       FIG. 11B  further shows that the outer surface of the insulating member  128  is spaced apart from the inner surface of the inductor coils  124 ,  126  by a distance  152 , measured in a direction perpendicular to a longitudinal axis  158  of the susceptor  132 . In one particular example, the distance  152  is about 0.05 mm. In another example, the distance  152  is substantially 0 mm, such that the inductor coils  124 ,  126  abut and touch the insulating member  128 . 
     In one example, the susceptor  132  has a wall thickness  154  of about 0.025 mm to 1 mm, or about 0.05 mm. 
     In one example, the susceptor  132  has a length of about 40 mm to 60 mm, about 40 mm to 45 mm, or about 44.5 mm. 
     In one example, the insulating member  128  has a wall thickness  156  of about 0.25 mm to 2 mm, 0.25 mm to 1 mm, or about 0.5 mm. 
     Although the devices illustrated in  FIGS. 1-11B  have heating elements for the aerosol-generating material that surround the heating chamber, it should be understood that other devices embodying the various aspects disclosed herein could have at least one heating element (shaped, for example, like a pin, rod or blade) that projects into the heating chamber so as to heat the aerosol-generating material from the inside outwards. The at least one heating element may, for example, be aligned with a longitudinal axis of the heating chamber. 
     “Session of use” as used herein refers to a single period of use of the aerosol provision device by a user. The session of use begins at the point at which power is first supplied to at least one heating unit present in the heating assembly. The device will be ready for use after a period of time has elapsed from the start of the session of use. The session of use ends at the point at which no power is supplied to any of the heating elements in the aerosol provision device. The end of the session of use may coincide with the point at which the smoking article is depleted (the point at which the total particulate matter yield (mg) in each puff would be deemed unacceptably low by a user). The session will have a duration of a plurality of puffs. Said session may have a duration less than 7 minutes, or 6 minutes, or 5 minutes, or 4 minutes and 30 seconds, or 4 minutes, or 3 minutes and 30 seconds. In some embodiments, the session of use may have a duration of from 2 to 5 minutes, or from 3 to 4.5 minutes, or 3.5 to 4.5 minutes, or suitably 4 minutes. A session may be initiated by the user actuating a button or switch on the device, causing at least one heating element to begin rising in temperature. 
     A “heating chamber” as used herein may for example refer to a space that is heating by at least one heating element of at least one heating unit. In some examples, the heating chamber may have two open ends (e.g. open proximal and distal ends) and there may, for instance, be an abrupt change in cross-sectional area at one or both of these open ends. In some examples, a proximal end of the inlet conduit may open into, or connect directly to, a distal end of the heating chamber. There may thus be an abrupt change in cross-sectional area between the proximal end of the inlet conduit and the distal end of the heating chamber. Hence (or otherwise), the cross-sectional area of the proximal end of the inlet conduit may be smaller than the cross-sectional area of the distal end of the heating chamber. 
     The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.