Heating Smokable Material Field
The invention relates to heating smokable material.
Background
Smoking articles such as cigarettes and cigars burn tobacco during use to create tobacco smoke. Attempts have been made to provide alternatives to these smoking articles by creating products which release compounds without creating tobacco smoke. Examples of such products are so-called heat-not-burn products which release compounds by heating, but not burning, tobacco.
Summary
According to the invention, there is provided an apparatus configured to heat smokable material to volatilize at least one component of the smokable material, comprising: a heater; and a heat conducting element, wherein the heat conducting element is configured to conduct heat from the heater into a smokable material heating region to heat smokable material. The heater may be located remotely from the smokable material heating region.
The heat conducting element may extend longitudinally across the smokable material heating region and may be configured to conduct heat to successive regions of smokable material in the smokable material heating region.
A first end of the heat conducting element may be arranged to be directly heated by the heater and a second end of the heat conducting element may be remote from the heater so as to be heated by conduction of heat from the first end. The heat conducting element may be configured to conduct heat from the first end to the second end so that the second end reaches substantially the same temperature as the first end after a period of between approximately five and ten minutes. The smokable material heating region may be a heating chamber for containing smokable material.
The heater may be located outside of the heating chamber and the heat conducting element may be located at least partially inside the heating chamber.
The heat conducting element may comprise a rod and the smokable material heating region may be located substantially co-axially outwardly of the rod. The rod may be substantially corkscrew shaped.
The heat conducting element may be substantially tubular and the smokable material heating region may be located substantially co-axially inwardly of the element. The apparatus may further comprise smokable material in the smokable material heating region.
The smokable material may comprise a cartridge configured to cooperate with a shape of the heat conducting element so as to receive heat from the element.
The heat conducting element may be configured to heat smokable material in the smokable material heating region to a temperature of at least 100°C.
The heat conducting element may be configured to heat smokable material in the smokable material heating region to a temperature of at least 120°C.
The heat conducting element may be configured to heat smokable material in the smokable material heating region to a temperature of between approximately 130°C and 180°C. The heat conducting element may be configured to heat smokable material in the smokable material heating region to a temperature in a range of approximately 150°C to 250°C. The apparatus may be configured to heat smokable material in the smokable material heating region without combusting the smokable material.
According to the invention, there is also provided a method of heating smokable material to volatilize at least one component of the smokable material, comprising conducting heat from a heater through a heat conducting element into a smokable material heating region to heat smokable material.
The heater may be located remotely from the smokable material heating region. For exemplary purposes only, embodiments of the invention are described below with reference to the accompanying figures in which:
Brief description of the figures
Figure 1 is a schematic illustration of an apparatus configured to heat smokable material to release aromatic compounds and/ or nicotine from the smokable material using a first configuration of heat conducting element;
figure 2 is a schematic illustration of an apparatus configured to heat smokable material to release aromatic compounds and/ or nicotine from the smokable material using a second configuration of heat conducting element;
figure 3 is a schematic illustration of an apparatus configured to heat smokable material to release aromatic compounds and/ or nicotine from the smokable material using a third configuration of heat conducting element;
figure 4 is a flow diagram showing a method of activating a heater and opening and closing heating chamber valves during puffing;
figures 5, 6 and 7 are illustrations of the propagation of heat from one end of a heat conducting element to the other end of the heat conducting element;
figure 8 is a schematic, cross-sectional illustration of a section of vacuum insulation configured to insulate heated smokable material from heat loss; figure 9 is a schematic, cross-sectional illustration of a heat resistive thermal bridge which follows an indirect path from a higher temperature insulation wall to a lower temperature insulation wall; and
figure 10 is a schematic illustration of communicative couplings between a controller and various apparatus components.
Detailed description
As used herein, the term 'smokable material' includes any material that provides volatilized components upon heating and includes any tobacco-containing material and may, for example, include one or more of tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes.
An apparatus 1 for heating smokable material comprises an energy source 2, a heater 3 and a heating chamber 4. The energy source 2 may comprise a battery such as a Li-ion battery, Ni battery, Alkaline battery and/ or the like, and is electrically coupled to the heater 3 to supply electrical energy to the heater 3 when required. The apparatus 1 also comprises a heat conducting element 25 which is configured to conduct heat from the heater 3 to the heating chamber 4. The heating chamber 4 is configured to receive smokable material 5 so that the smokable material 5 can be heated in the heating chamber 4. For example, the heating chamber 4 may be located around or inside the heat conducting element 25 so that thermal energy which has been conducted from the heater 3 via the heat conductive element 25 to the heating chamber 4 heats the smokable material 5 therein to volatilize aromatic compounds and nicotine in the smokable material 5 without burning the smokable material 5. A mouthpiece 6 is provided through which a user of the apparatus 1 can inhale the volatilized compounds during use of the apparatus 1. The smokable material 5 may comprise a tobacco blend. The heat conducting element 25 may comprise a substantially elongate element 25. As is described in more detail below, the element 25 is configured to conduct heat from one of its ends 26, which is coupled directly to the heater 3, to the other of its ends 27 so as to progressively heat more of the heating chamber 4 and smokable material 5 therein as time passes.
For example, as shown in figure 1, the heat conducting element 25 may comprise a thermally conductive rod 25. The rod 25 may be cylindrical or any other suitable shape. For example, the heat conducting rod 25 may comprise an elongate element 25 having a substantially triangular cross-sectional shape. Another alternative is an elongate element 25 having a rectangular cross-sectional shape such as a square. In this configuration, the heating chamber 4 is located around an external, for example circumferential, longitudinal surface of the heat conducting rod 25. The heating chamber 4 and smokable material 5 therein therefore comprise co-axial layers around the heat conducting element 25. However, other shapes and configurations of the heat conducting element 25 and heating chamber 4 can alternatively be used. For example, in a first alternative configuration, the heat conducting element 25 comprises a spirally shaped thermally conductive element 25. An example is shown in figure 2. The spirally shaped heat conducting element 25 may be configured to screw into the smokable material 5, for example in the manner of a corkscrew, when the smokable material 5 is inserted into the heating chamber 4.
In both of these configurations, the heat conducting element 25 is located in a central region of the housing 7 and the heating chamber 4 and smokable material 5 are located around the longitudinal surface of the heat conducting element 25. Thermal energy emitted by the heat conducting element 25 travels in a radial direction outwards from the longitudinal surface of the element 25 into the heating chamber 4 and the smokable material 5 therein.
However, in a second alternative configuration, the heat conducting element 25 comprises a substantially hollow tube, which may be cylindrical, and the heating chamber 4 is located inside the tube 3 rather than around the outside of the heat conducting element 25. An example is shown in figure 3. The heat conducting element 25 is therefore arranged to heat smokable material 5 located radially inwardly from the element 25 in the heating chamber 4, rather than radially outwardly as previously described. Thermal energy emitted by the heat conducting element 25 travels in a radial direction inwards from a longitudinal surface of the element 25 into the heating chamber 4. As with the configurations described previously, the heat conducting element 25 may alternatively have a substantially rectangular or triangular cross-sectional shape, or any other suitable cross-sectional shape.
A housing 7 may contain components of the apparatus 1 such as the energy source 2, heater 3 and heat conducting element 25. As shown in figure 1, the housing 7 may comprise an approximately cylindrical tube with the energy source 2 located towards its first end 8 and the mouthpiece 6 located towards its opposite, second end 9. The heat conducting element 25, heating chamber 4 and heater 3 are located between the energy source 2 and the mouthpiece 6. The energy source 2, heat conducting element 25 and heater 3 extend along the longitudinal axis of the housing 7. For example, as shown in figures 1 to 3, the energy source 2, heat conducting element 25 and heater 3 can be aligned along the central longitudinal axis of the housing 7 in an end-to-end arrangement so that an end face of the energy source 2 faces an end face 27 of the heat conducting element 25. The opposite end face 26 of the heat conducting element 25 faces and is thermally coupled to the heater 3. The heater 3 is located externally of the smokable material 5 and heating chamber 4. The location of the heater 3 in the housing 7 may be downstream of the smokable material 5 and heating chamber 4.
The length of the housing 7 may be approximately 130mm. Within the housing 7, the length of energy source 2 may be approximately 59mm, and the length of the heating chamber 4 may be approximately 50mm. The length of the heat conducting element 25 is at least approximately the same length as the heating chamber 4 so that the heat conducting element 25 extends across the full length of the heating chamber 4. The diameter of the housing 7 may be between approximately 15mm and approximately 18mm. For example, the diameter of the housing's first end 8 may be 18mm whilst the diameter of the mouthpiece 6 at the housing's second end 9 may be 15mm. The diameter of the heat conducting element 25 may be between approximately 2.0mm and approximately 6.0mm. The diameter of the heat conducting element 25 may, for example, be between approximately 4.0mm and approximately 4.5mm or between approximately 2.0mm and approximately 3.0mm. Diameters outside these ranges may alternatively be used, particularly with the second alternative configuration of heat conducting element 25.
The heating chamber 4 may have an exterior diameter of approximately 10mm at its outwardly-facing surface. The diameter of the energy source 2 may be between approximately 14.0mm and approximately 15.0mm, such as 14.6mm. The housing 7 is suitable for being gripped by a user during use of the apparatus 1 so that the user can inhale volatilized smokable material compounds from the mouthpiece 6 of the apparatus 1.
Heat insulation 28 may be provided between the energy source 2 and the heating chamber 4 to prevent direct transfer of heat from one to the other. Heat insulation 28 may also be provided between the heater 3 and the heating chamber 4 so that heat from the heater 3 does not enter the heating chamber 4 by any means other than the heat conducting element 25. The insulation 28 may comprise vacuum insulation, a discussion of which is provided further below As referred to previously, the heater 3 is thermally coupled to an end 26 of the heat conducting element 25 so that the end 26 of the heat conducting element 25 is directly heated by the heater 3. The opposite end 27 of the heat conducting element 25 is not heated by direct contact with the heater 3, but receives heat by thermal conduction along the element 25. The heat conducting element 25 is formed of a thermally conductive material. The properties of the material are selected so that heat propagates relatively slowly along the element 25 from one end 26 to the other end 27. The time taken for the end 27 of the heat conducting element 25 which is furthest from the heater 3 to reach full operating temperature may be predetermined and may correspond to a normal smoking period for a cigarette. An example period is approximately ten minutes, as explained in more detail below. In this way, as time passes after activation of the heater 3, the passive heat conducting element 25 heats more of the smokable material 5 in the chamber 4. This causes a consistent release of volatile inhalable compounds from the freshly heated smokable material 5 in the chamber 4.
The heater 3 may comprise a ceramics heater 3. The ceramics heater 3 may, for example, comprise base ceramics of alumina and/ or silicon nitride which are laminated and sintered. Other types of heater 3 can alternatively be used.
The smokable material 5 may be comprised in a cartridge 11 which can be inserted into the heating chamber 4. For example, as shown in figure 1 , the cartridge 11 can comprise a smokable material tube 11 which can be inserted into the chamber 4 around the heat conducting element 25 so that the internal surface of the smokable material tube 11 faces the longitudinal surface of the heat conducting element 25. The cartridge 11 may comprise a longitudinal bore through its centre to facilitate the smokable material 5 being pushed over the conducting element 25. The diameter of the hollow bore may be substantially equal to, or slightly larger than, the diameter of the heat conducting element 25 so that the tube 11 is a close fit around the heat conducting element 25. If the cartridge 11 is not hollow, the heat conducting rod 25 may be configured to penetrate the smokable material cartridge 11 when the cartridge 11 is loaded into the heating chamber 4. An end 27 of the heat conducting element 25 may comprise a penetrative tip for aiding this process.
Alternatively, as shown in figure 3, the cartridge 11 may comprise a smokable material rod 11 which can be inserted into a cavity defined by the tubular heat conducting element 25 discussed above. The diameter of the smokable material rod 11 may be substantially equal to the diameter of the cavity defined by the heat conducting element 25 so as to provide a close fit.
The length of the cartridge 11 may be approximately equal to the length of the heat conducting element 25 and the heating chamber 4 so that the heat conducting element 25 can heat the cartridge 11 along its whole length as heat energy propagates along the conducting element 25 from one end 26 to the other end 27. Heat transfer from the heat conducting element 25 to the smokable material 5 may be via direct contact between the element 25 and the smokable material 5. The external heating surface of the heat conducting element 25 which is in direct contact with the smokable material 5 during use of the apparatus 1 may be embossed to increase the surface area of the element 25 and thereby increase the rate of heat transfer to the smokable material 5.
The housing 7 of the apparatus 1 may comprise an opening through which the cartridge 11 can be inserted into the heating chamber 4. The opening may, for example, comprise a ring or circular-shaped opening located at the housing's second end 9 so that the cartridge 11 can be slid into the opening and pushed directly into the heating chamber 4. The opening is preferably closed during use of the apparatus 1 to heat the smokable material 5. Alternatively, a section of the housing 7 at the second end 9 is removable from the apparatus 1 so that the smokable material 5 can be inserted into the heating chamber 4. The apparatus 1 may optionally be equipped with a user-operable smokable material ejection unit, such as an internal mechanism configured to slide used smokable material 5 off and/or away from the heat conducting element 25. The used smokable material 5 may, for example, be pushed back through the opening in the housing 7. A new cartridge 11 can then be inserted as required.
Referring to figure 10, the apparatus 1 may comprise a controller 12, such as a microcontroller 12, which is configured to control operation of the apparatus 1. The controller 12 is electronically connected to the other components of the apparatus 1 such as the energy source 2 and heater 3 so that it can control their operation by sending and receiving signals. The controller 12 is, in particular, configured to control activation of the heater 3 to cause heating of the smokable material 5 via the thermally conductive element 25. For example, the controller 12 may be configured to activate the heater 3 in response to a user drawing on the mouthpiece 6 of the apparatus 1. In this regard, the controller 12 may be in communication with a puff sensor 13 via a suitable communicative coupling. The puff sensor 13 is configured to detect when a puff occurs at the mouthpiece 6 and, in response, is configured to send a signal to the controller 12 indicative of the puff. An electronic signal may be used. The controller 12 may respond to the signal from the puff sensor 13 by activating the heater 3 and thereby cause heating of the smokable material 5 via the heat conducting element 25. The use of a puff sensor 13 to activate the heater 3 is not, however, essential and other means for providing a stimulus to activate the heater 3 can alternatively be used. For example, the controller 12 may be configured to activate the heater 3 in response to another type of activation stimulus such as the actuation of a user-operable actuator. An example is a switch 29 which is selectively actuatable by a user of the apparatus 1. The volatilized compounds released during heating can then be inhaled by the user through the mouthpiece 6. The controller 12 can be located at any suitable position within the housing 7.
Referring to figures 4 to 7, an example heating method may comprise a first step SI in which an activation stimulus, such as a first puff, is detected followed by a second step S2 in which the heater 3 is activated to begin heating the heat conducting element 25 in response to the activation stimulus. This causes smokable material 5 which is located closest to the first end 26 of the heat conducting element 25 to be heated due to propagation of heat a short distance through the heat conducting rod 25. As time passes after activation of the heater 3, heat propagates further along the heat conducting rod 25 causing more of the heat conducting element 25 to be heated and thereby volatize compounds from the smokable material 5. Therefore, as time passes, more and more of the smokable material 5 in the heating chamber 4 is heated by the heat conducting element 25. This
progressive heating of the smokable material 5 over time causes a corresponding release of volatile compounds from the smokable material 5, which can then be inhaled by a user of the apparatus 1 in successive puffs in the mouthpiece 6.
Because fresh smokable material 5 is always being heated due to the steady progress of heat along the heat conducting element 25, the amount of freshly volatized inhalable compounds remains approximately consistent for each successive puff. For example, following the initial activation of the heater 3, a third step S3 of the method may comprise opening hermetically sealable inlet and outlet valves 24 to allow air to be drawn from the exterior of the housing 7 through the heating chamber 4 and out of the apparatus 1 through the mouthpiece 6, thereby carrying freshly volatized compounds from the smokable material which is located closest to the end 26 of the heat conducting element 25 being directly heated by the heater 3. In a fourth step S4, the valves 24 are closed. The third and fourth steps S3, S4 may occur in response to detection of a beginning and an end of a puff respectively. The valves 24 are described in more detail below with respect to figure 1. In fifth S5, sixth S6 and seventh S7 steps, the valves 24 re-open and re-close to allow more air to be drawn through the heating chamber 4 and out of the mouthpiece 6. As with the first volume of air, the second volume of air drawn through the heating chamber 4 carries freshly volatized compounds to the mouthpiece 6. These freshly volatized compounds are those that have been released by the propagation of heat along the heat conducting element 25 since the time of the last opening and closing of the valves 24. As before, the opening and closing of the valves 24 may occur in response to detection of a beginning and an end of a puff. This process continues for successive puffs. The temperature of the heating element 3 may be kept constant during use of the apparatus 1 and may be monitored using a temperature sensor, such as a
thermocouple (not shown), connected to the controller 12.
The controller 12 may be configured to de-activate the heater 3 after a
predetermined period, which may for example be approximately ten minutes after activation as previously described. The controller 12 may, for example, comprise a suitable timer, such as a counter stored in a memory of the controller 12, for counting the predetermined period. A suitable range is between five and ten minutes after activation of the heater 3. Alternatively, the heater 3 may be de- activated following a detection that the end 27 of the heat conducting element 25 which is furthest from the heater 3 has reached full operating temperature since this is an indication that all of the smokable material 5 in the chamber 4 has been heated. In this way, a fresh section of smokable material 5 is heated to volatilize nicotine and aromatic compounds for each new puff. The configuration and the materials used in the heater 3 and heat conducting element 25 may be such that the end 27 of the heat conducting element 25 which is furthest from the heater 3 only reaches full operating temperature after the predetermined period referred to above has elapsed. As illustrated in figures 5 to 7, in between the start and end of the predetermined period the conducting element 25 may be heated at a consistent rate so that the length of the element 25 heats smoothly in a linear fashion from one end 26 to the other 27. Once a particular region of the conductive element 25 has been heated to operating temperature, it remains substantially at that temperature until de-activation of the heater 3 causes it to cool.
Once all of the smokable material 5 has been heated by the heat conducting element 25, the controller 12 may be configured to indicate to the user that the cartridge 11 should be changed. The controller 12 may, for example, activate an indicator light at the external surface of the housing 7. The light may optionally also act as an indication that the user should switch off the heater 3, for example using the switch previously described.
It will be appreciated that progressively heating the smokable material 5 by thermal propagation along a heat conductive element 25 means that the heating apparatus 1 can be used to progressively heat different regions of the smokable material 5 over time to release inhalable aromatics and other compounds. There is no need for the use of a plurality of individually operable heating elements configured to heat different regions of the chamber 4. There is also no requirement for control programs for activating and de-activating such a plurality of heating elements during heating of a cartridge 11.
If the smokable material 5 comprises tobacco, a suitable temperature for volatilizing the nicotine and other aromatic compounds may be 100°C or above, such as 120°C or above. An example is a temperature between 100°C and 250°C, such as between 150°C and 250°C or between 130°C and 180°C. The temperature may be more than 100°C. An example of a full operating temperature of the heat conducting element 25 is 150°C, although other values such as 120°C and 250°C are also possible. Once the heater 3 has been activated, it may remain fully activated until the heater 3 is switched off. Therefore, the power supplied to the heater 3 remains substantially constant during use of the apparatus 1 to heat the smokeable material 5. The continued activation of the heater 3, causing heated regions of the heat conducting element 25 to retain full operating temperature until the heater 3 is de-activated, substantially prevents condensation of compounds such as nicotine volatized from the smokable material 5 in the heating chamber 4.
Referring to figure 1, the apparatus 1 may comprise air inlets 14 which allow external air to be drawn into the housing 7 and through the heated smokable material 5 during puffing. Each inlet 14 may direct external air to one or more of the hermetically sealable valves 24. The air inlets 14 comprise apertures 14 in the housing 7 and may be located upstream from the smokable material 5 and heating chamber 4 towards the first end 8 of the housing 7. Air drawn in through the inlets 14 travels through the heated smokable material 5 and therein is enriched with smokable material vapours, such as aroma vapours, before being inhaled by the user at the mouthpiece 6. Optionally, the apparatus 1 may comprise a heat exchanger configured to warm the air before it enters the smokable material 5 and/ or to cool the air before it is drawn through the mouthpiece 6. For example, the heat exchanger may be configured to use heat extracted from the air entering the mouthpiece 6 to warm new air before it enters the smokable material 5.
Referring to figure 8, thermal insulation 18 may be provided between the smokable material 5 and an external surface 19 of the housing 7 to reduce heat loss from the apparatus 1 and therefore improve the efficiency with which the smokable material 5 is heated. For example, a wall of the housing 7 may comprise a layer of insulation 18 which extends around the outside of the heating chamber 4. The insulation layer 18 may comprise a substantially tubular length of insulation 18 located co-axially around the heating chamber 4, heat conducting element 25 and smokable material 5. It will be appreciated that the insulation 18 could also be comprised as part of the hollow tubular smokable material cartridge 11 described above, in which it would be located co-axially around the outside of the smokable material 5.
The insulation 18 may comprise vacuum insulation 18. For example, the insulation 18 may comprise a layer which is bounded by a wall material 19 such as a metallic material. An internal region or core 20 of the insulation 18 may comprise an open- cell porous material, for example comprising polymers, aerogels or other suitable material, which is evacuated to a low pressure. The pressure in the internal region 20 may be in the range of 0.1 to 0.001 mbar. The wall 19 of the insulation 18 is sufficiently strong to withstand the force exerted against it due to the pressure differential between the core 20 and external surfaces of the wall 19, thereby preventing the insulation 18 from collapsing. The wall 19 may, for example, comprise a stainless steel wall 19 having a thickness of approximately ΙΟΟμπι. The thermal conductivity of the insulation 18 may be in the range of 0.004 to 0.005 W/mK. The heat transfer coefficient of the insulation 18 may be between approximately 1.10 W/ (m2K) and approximately 1.40 W/(m2K) within a
temperature range of between 100 degrees Celsius and 250 degrees Celsius, such as between approximately 150 degrees Celsius and approximately 250 degrees Celsius. The gaseous conductivity of the insulation 18 is negligible. A reflective coating may be applied to the internal surfaces of the wall material 19 to minimize heat losses due to radiation propagating through the insulation 18. The coating may, for example, comprise an aluminium IR reflective coating having a thickness of between approximately 0.3μπι and Ι .Ομπι. The evacuated state of the internal core region 20 means that the insulation 18 functions even when the thickness of the core region 20 is very small. The insulating properties are substantially unaffected by its thickness. This helps to reduce the overall size of the apparatus 1. As shown in figure 8, the wall 19 may comprise an inwardly- facing section 21 and an outwardly-facing section 22. The inwardly-facing section 21 substantially faces the smokable material 5 and heating chamber 4. The outwardly-facing section 22 substantially faces the exterior of the housing 7. During operation of the apparatus 1, the inwardly- facing section 21 may be warmer due to the thermal energy originating from the heat conducting element 25, whilst the outwardly-facing section 22 is cooler due to the effect of the insulation 18. The inwardly-facing section 21 and the outwardly-facing section 22 may, for example, comprise substantially parallel longitudinally-extending walls 19 which are at least as long as the heat conducting element 25. The internal surface of the outwardly-facing wall section 22, i.e. the surface facing the evacuated core region 20, may comprise a coating for absorbing gas in the core 20. A suitable coating is a titanium oxide film. A thermal bridge 23 may connect the inwardly-facing wall section 21 to the outwardly-facing wall section 22 at one or more edges of the insulation 18 in order to completely encompass and contain the low pressure core 20. The thermal bridge 23 may comprise a wall 19 formed of the same material as the inwardly and outwardly-facing sections 21, 22. A suitable material is stainless steel, as previously discussed. The thermal bridge 23 has a greater thermal conductivity than the insulating core 20 and therefore may undesirably conduct heat out of the apparatus 1 and, in doing so, reduce the efficiency with which the smokable material 5 is heated.
To reduce heat losses due to the thermal bridge 23, the thermal bridge 23 may be extended to increase its resistance to heat flow from the inwardly- facing section 21 to the outwardly-facing section 22. This is schematically illustrated in figure 9. For example, the thermal bridge 23 may follow an indirect path between the inwardly- facing section 21 of wall 19 and the outwardly-facing section 22 of wall 19. This may be facilitated by providing the insulation 18 over a longitudinal distance which is longer than the lengths of the heater 3, heating chamber 4 and smokable material 5 so that the thermal bridge 23 can gradually extend from the inwardly- facing section 21 to the outwardly-facing section 22 along the indirect path, thereby reducing the thickness of the core 20 to zero, at a longitudinal location in the housing 7 where the heater 3, heat conducting element 25, heating chamber 4 and smokable material 5 are not present.
As previously discussed, the heating chamber 4 insulated by the insulation 18 may comprise inlet and outlet valves 24 which hermetically seal the heating chamber 4 when closed. The valves 24 can thereby prevent air from undesirably entering and exiting the chamber 4 and can prevent smokable material flavours from exiting the chamber 4. The inlet and outlet valves 24 may, for example, be provided in the insulation 18. For example, between puffs, the valves 24 may be closed by the controller 12 so that all volatilized substances remain contained inside the chamber 4 in-between puffs. The partial pressure of the volatized substances between puffs reaches the saturated vapour pressure and the amount of evaporated substances therefore depends only on the temperature in the heating chamber 4. This helps to ensure that the delivery of volatilized nicotine and aromatic compounds remains constant from puff to puff. During puffing, the controller 12 is configured to open the valves 24 so that air can flow through the chamber 4 to carry volatilized smokable material components to the mouthpiece 6. A membrane can be located in the valves 24 to ensure that no oxygen enters the chamber 4. The valves 24 may be breath-actuated so that the valves 24 open in response to detection of a puff at the mouthpiece 6. The valves 24 may close in response to a detection that a puff has ended. Alternatively, the valves 24 may close following the elapse of a predetermined period after their opening. The predetermined period may be timed by the controller 12. Optionally, a mechanical or other suitable opening/closing means may be present so that the valves 24 open and close automatically. For example, the gaseous movement caused by a user puffing on the mouthpiece 6 may be used to open and close the valves 24. Therefore, the use of the controller 12 is not necessarily required to actuate the valves 24.
The mass of the apparatus 1 as a whole may be in the range of 70 to 125g. A battery 2 with a capacity of 1000 to 3000mAh and voltage of 3.7V can be used.
It will be appreciated that any of the alternatives described above can be used singly or in combination.
In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed invention(s) may be practiced and provide for superior smokable material heating apparatuses and methods. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/ or exclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope and/or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. In addition disclosure includes other inventions not presently claimed, but which may be claimed in future.