Evaporator device

Abstract

The present invention provides an evaporator device comprising: a housing comprising an air inlet; a heating element within the housing, the heating element comprising a non-linear positive resistivity temperature coefficient material; a heat exchanger thermally coupled to the heating element and arranged to receive the airflow from the air inlet, the heat exchanger configured to transfer heat between the heating element and the airflow to generate a heated airflow wherein the heated airflow exiting the heat exchanger is configured to vaporize the vaporizable material; a cartridge having a first air inlet, where the cartridge comprises: a stocker containing a vaporizable material; a wicking device in fluid communication with the vaporizable material, the wicking device being arranged to receive the heated airflow from the heat exchanger to vaporize the vaporizable material to produce a vapor and / or a first aerosol; and a mouthpiece configured to receive the vapor and / or the first aerosol through a vapor inlet.

Description

[0001] This patent application is a divisional application of Chinese Patent Application No. CN 202180029707.3 (International Application No. PCT / US2021 / 018327) titled "Mouthpiece for Vaporizer Including Positive Temperature Coefficient of Resistivity Heater" filed on February 17, 2021.

[0002] Cross - Reference

[0003] This application claims the priority of U.S. Provisional Patent Application No. 62 / 978,236 titled "Mouthpiece for Vaporizer Including Positive Temperature Coefficient of Resistivity Heater" filed on February 18, 2020, which is incorporated herein by reference in its entirety to the extent permitted. Technical Field

[0004] The subject matter described herein relates to vaporizer devices, such as portable personal vaporizer devices, which are used to produce an inhalable aerosol from one or more vaporizable materials and include a heating element and a mouthpiece that utilize a semiconductor material having a non - linear positive temperature coefficient of resistivity (PTCR). Background Art

[0005] Vaporizer devices, which may also be referred to as electronic vaporizer devices or e - vaporizer devices, can be used to deliver an aerosol (sometimes also referred to as "vapor") containing one or more active ingredients by inhalation of the aerosol by a user of the device. An electronic cigarette, which may also be referred to as an e - cigarette, is a type of vaporizer device that is typically battery - powered and can be used to simulate the experience of smoking without burning tobacco or other substances. When using a vaporizer device, a user inhales an aerosol commonly referred to as vapor, which can be produced by a heating element that evaporates (generally causing a liquid or solid to at least partially transform into the gas phase) a vaporizable material, which can be in the form of a liquid, solution, solid, wax, or any other form as long as it is compatible with the use of a particular vaporizer device.

[0006] To receive the inhalable aerosol generated by the evaporator device, in some examples, the user can activate the evaporator device by sucking, by pressing a button, or by some other method. Sucking, as a commonly used term (and also used herein), refers to the inhalation by the user in such a way that a certain volume of air is drawn through the evaporator device, such that the evaporated evaporable material combines with the air to produce an inhalable aerosol. A typical method for an evaporator device (e.g., which may include an air inlet, an air outlet fluidly coupled to a mouthpiece, and an evaporation chamber therebetween) to produce an inhalable aerosol from an evaporable material includes heating the evaporable material in the evaporation chamber (sometimes also referred to as the heating chamber) to convert the evaporable material into the gaseous (vapor) phase. The evaporation chamber generally refers to an area or volume within the evaporator device where a heat source heats the evaporable material to produce a mixture of air and the evaporable material, achieving a certain equilibrium between the gaseous phase and the condensed phase (e.g., liquid and / or solid).

[0007] Some components of the gaseous-phase evaporable material may condense after evaporation due to cooling and / or pressure changes, thereby forming an aerosol that includes condensed-phase (e.g., liquid and / or solid) particles suspended in at least some of the air inhaled through the evaporator device by sucking. If the evaporable material includes semi-volatile compounds (e.g., compounds such as nicotine that have a relatively low vapor pressure at the inhalation temperature and pressure), the inhalable aerosol may include semi-volatile compounds in some local equilibrium between the gaseous phase and the condensed phase. SUMMARY OF THE INVENTION

[0008] In one aspect, a mouthpiece for an evaporator device includes a vapor inlet, an aerosol outlet, a first plurality of air inlets, and a second plurality of air inlets. The first plurality of air inlets are disposed between the vapor inlet and the aerosol outlet and are configured to provide a first plurality of air streams. The first plurality of air streams form a first vortex. The first vortex has a first axis of rotation and a first direction of rotation about the first axis of rotation. The second plurality of air inlets are also disposed between the vapor inlet and the aerosol outlet and are configured to provide a second plurality of air streams. The second plurality of air streams form a second vortex. The second vortex has a second axis of rotation and a second direction of rotation about the second axis of rotation. The first plurality of air streams and the second plurality of air streams are configured to mix with the vapor entering through the vapor inlet and form an aerosol that exits through the aerosol outlet.

[0009] One or more of the following features may be included in any feasible combination. For example, each inlet of the first plurality of air inlets may be a round hole that passes through a certain thickness of the mouthpiece and forms an angle of about 15 degrees to 45 degrees with the outer surface of the mouthpiece. The interior of the angle for each round hole may open towards the first rotational direction. Each inlet of the second plurality of air inlets may also be a round hole that passes through a certain thickness of the mouthpiece and forms an angle of about 15 degrees to 45 degrees with the outer surface of the mouthpiece. The interior of the angle for each round hole of the second plurality of air inlets may open towards the second rotational direction. The first rotational direction and the second direction may be opposite directions. For example, the first rotational direction may be counterclockwise and the second rotational direction may be clockwise. The first rotational axis and the second rotational axis may not be parallel. The first plurality of air inlets and the second plurality of air inlets may provide a turbulent mixing of the inlet air and the vapor entering the mouthpiece from the vapor inlet. The first plurality of air inlets and the second plurality of air inlets may be arranged in a plane. The first plurality of air inlets and the second plurality of air inlets may each be arranged in a circular shape. The cross-sectional area of the vapor inlet may be at least four times the cross-sectional area of the aerosol outlet. The vapor inlet may have a vapor inlet temperature, and the aerosol outlet may have an aerosol outlet temperature, and the difference between the vapor inlet temperature and the aerosol outlet temperature may be at least 100 °C.

[0010] In another aspect, an evaporator device includes a housing that includes an air inlet. The evaporator device further includes a heating element within the housing. The heating element includes a material having a non-linear positive resistivity temperature coefficient. The evaporator device further includes a heat exchanger that is thermally coupled to the heating element and is arranged to receive an air flow from the air inlet. The heat exchanger is configured to transfer heat between the heating element and the air flow to produce a heated air flow. The heated air flow exiting the heat exchanger is configured to evaporate an evaporable material. The evaporator device further includes a mouthpiece that is configured to receive the evaporated evaporable material through a vapor inlet. The mouthpiece has a vapor inlet, an aerosol outlet, a first plurality of air inlets, and a second plurality of air inlets. The first plurality of air inlets are disposed between the vapor inlet and the aerosol outlet and are configured to provide a first plurality of air streams. The first plurality of air streams form a first vortex. The first vortex has a first rotational axis and a first rotational direction around the first rotational axis. The second plurality of air inlets are also disposed between the vapor inlet and the aerosol outlet and are configured to provide a second plurality of air streams. The second plurality of air streams form a second vortex. The second vortex has a second rotational axis and a second rotational direction around the second rotational axis. The first plurality of air streams and the second plurality of air streams are configured to mix with the evaporated evaporable material entering from the vapor inlet and form an aerosol that exits through the aerosol outlet.

[0011] One or more of the following features may be included in any feasible combination. For example, each inlet of the first plurality of air inlets may be a round hole that passes through a certain thickness of the mouthpiece and forms an angle between about 15 degrees and 45 degrees with the outer surface of the mouthpiece. The interior of the angle for each round hole may be open towards the first rotational direction. Each inlet of the second plurality of air inlets may also be a round hole that passes through a certain thickness of the mouthpiece and forms an angle between about 15 degrees and 45 degrees with the outer surface of the mouthpiece. The interior of the angle for each round hole of the second plurality of air inlets may be open towards the second rotational direction. The first rotational direction and the second direction may be opposite directions. For example, the first rotational direction may be counterclockwise and the second rotational direction may be clockwise. The first rotational axis and the second rotational axis may not be parallel. The first plurality of air inlets and the second plurality of air inlets may provide a turbulent mixing of the inlet air and the vapor entering the mouthpiece from the vapor inlet. The first plurality of air inlets and the second plurality of air inlets may be arranged in a plane. The first plurality of air inlets and the second plurality of air inlets may each be arranged in a circular pattern. The cross-sectional area of the vapor inlet may be at least four times the cross-sectional area of the aerosol outlet. The vapor inlet may have a vapor inlet temperature and the aerosol outlet may have an aerosol outlet temperature, and the difference between the vapor inlet temperature and the aerosol outlet temperature may be at least 100 °C. The heat exchanger may include a first heat exchanger thermally coupled to the first side of the heating element. The heat exchanger may include a second heat exchanger thermally coupled to the second side of the heating element. The heat exchanger may include a plurality of fin features. The heat exchanger may be made of aluminum, copper, steel, stainless steel, or titanium. The heat exchanger may be made by extrusion of a thermally conductive material. The device may include a diverter located in the airflow path, the diverter being configured to divert a portion of the airflow through the heat exchanger. The housing may include a heater assembly cover that houses the heat exchanger. The device may include a power source configured to provide electrical energy to heat the heating element. The device may include a cartridge located downstream of the heating element and oriented to receive the heated airflow, where downstream is with respect to the airflow. The housing may include a connector configured to couple the housing to a cartridge containing an evaporable material. The evaporable material may be a solid evaporable material.

[0012] The evaporator device may include a cartridge configured to hold an evaporable material. The cartridge may include a first air inlet. The housing may include a connector configured to couple the housing to the cartridge. The cartridge may include a solid evaporable material. The cartridge may include a reservoir, a liquid evaporable material within the reservoir, and a wick in fluid communication with the liquid evaporable material, wherein the cartridge is configured to receive a heated air stream and direct the heated air stream across the wick. The cartridge may include a mouthpiece, and the wick may be located in an air flow path between a heating element and the mouthpiece. The cartridge may include a second air inlet configured to draw a second air stream into the cartridge for mixing with the heated air stream and within a condensation chamber located downstream in the air flow path of the heat exchanger and the evaporable material. The cartridge may include a reservoir, a liquid evaporable material within the reservoir, and a wick in fluid communication with the liquid evaporable material. The wick may be arranged to receive a heated air stream from the heat exchanger to produce an evaporated evaporable material in the form of a vapor and / or a first aerosol. The solid evaporable material may be arranged to receive the vapor and / or the first aerosol and produce a second aerosol. The mouthpiece may be configured to receive the second aerosol after the vapor and / or the first aerosol passes through the solid evaporable material.

[0013] The evaporator device may include a first cartridge containing an evaporable material, a first air inlet, and a wick. The evaporable material may be a liquid evaporable material, and the wick may be in fluid communication with the liquid evaporable material. The wick may be arranged to receive a heated air stream from a heat exchanger through the first air inlet to evaporate the evaporable material, thereby producing a vapor and / or a first aerosol. The evaporator device may further include a second cartridge containing a solid evaporable material and a mouthpiece. The solid evaporable material may be arranged to receive the vapor and / or the first aerosol to produce a second aerosol. The mouthpiece may be configured to receive the second aerosol after the vapor and / or the first aerosol passes through the solid evaporable material. The first cartridge may be removably coupled to the housing. The second cartridge may be removably coupled to the housing and / or the first cartridge. The first cartridge and the second cartridge may be disposable cartridges. The second cartridge may include a second air inlet for mixing ambient temperature air with the evaporated evaporable material after the evaporated evaporable material passes through the solid evaporable material. The device may include a fibrous body arranged to receive and cool the second aerosol after the vapor and / or the first aerosol passes through the solid evaporable material.

[0014] The non-linear positive resistivity temperature coefficient material includes a resistivity transition region in which the resistivity increases within a certain temperature range such that when the heating element is heated to a temperature higher than a first temperature within the resistivity transition region, the current from the power source is reduced to a level that limits further temperature rise of the heating element. The resistivity transition region may start at a first temperature between 150 °C and 350 °C. The resistivity transition region may start at a first temperature between 220 °C and 300 °C. The resistivity transition region may start at a first temperature between 240 °C and 280 °C. The increase in resistivity within the temperature range of the resistivity transition region may include an increase factor of at least 10, an increase factor of at least 100, or an increase factor of at least 1000. The increase factor characterizes the relative resistivity change between the resistivity at the first temperature associated with the start of the resistivity transition region and the resistivity at a second temperature associated with the end of the resistivity transition region. The resistivity transition region may start at a first temperature, and the resistivity of the heating element at a temperature below the first temperature may be between 0.2 ohm-cm and 200 ohm-cm, between 2.0 ohm-cm and 20 ohm-cm, or between 20 ohm-cm and 200 ohm-cm.

[0015] The device may include a power source configured to supply current to the heating element at a voltage between 3 volts and 50 volts, a pressure sensor, and a controller coupled to the pressure sensor and configured to detect inhalation and, in response, electrically connect the power source to the heating element. The housing may be cylindrical, the heating element may be cylindrical, and the heat exchanger may be cylindrical. The housing may also be rectangular, the heating element may also be rectangular, and the heat exchanger may also be rectangular. The power source may supply direct current (DC) or alternating current (AC).

[0016] The evaporator device may include an input terminal configured to electrically connect the power source to the PTCR heating element (PTCR heater) in response to a user input. The input terminal may include a button. The PTCR heating element of the evaporator device is self-regulating to maintain a predetermined temperature at startup. The evaporator device does not require a pressure sensor and / or a controller coupled to the pressure sensor to electrically connect the power source to the PTCR heating element and regulate its temperature.

[0017] On the other hand, an evaporator device for evaporating a solid evaporable material using a heated air stream includes a housing that includes an air inlet and a power source configured to supply an electric current at a certain voltage, and a PTCR heater assembly within the housing. The PTCR heater assembly includes a heating element that is within the housing and is configured to be electrically coupled to the power source to receive the current. The PTCR heating element includes a PTCR material having a resistivity that varies based on temperature. The resistivity includes a resistivity transition region in which the resistivity increases within a certain temperature range such that when the PTCR heating element is heated to a temperature higher than a first temperature within the transition region, the current from the power source is reduced to a level that limits further temperature rise of the PTCR heating element. The heater assembly further includes a heat exchanger that is thermally coupled to the heating element and is arranged to receive an air stream from the air inlet. The heat exchanger is configured to transfer heat between the heating element and the air stream to produce a heated air stream. The heated air stream exiting the heat exchanger is configured to evaporate the solid evaporable material. The evaporator device further includes a nozzle that is configured to receive the evaporated evaporable material through a vapor inlet. The nozzle has a vapor inlet, an aerosol outlet, a first plurality of air inlets, and a second plurality of air inlets. The first plurality of air inlets are disposed between the vapor inlet and the aerosol outlet and are configured to provide a first plurality of air streams. The first plurality of air streams form a first vortex. The first vortex has a first axis of rotation and a first direction of rotation about the first axis of rotation. The second plurality of air inlets are also disposed between the vapor inlet and the aerosol outlet and are configured to provide a second plurality of air streams. The second plurality of air streams form a second vortex. The second vortex has a second axis of rotation and a second direction of rotation about the second axis of rotation. The first plurality of air streams and the second plurality of air streams are configured to mix with the evaporated evaporable material entering through the vapor inlet and form an aerosol that exits through the aerosol outlet.

[0018] One or more of the following features may be included in any feasible combination. For example, each inlet of the first plurality of air inlets may be a round hole that passes through a certain thickness of the mouthpiece and forms an angle of about 15 degrees to 45 degrees with the outer surface of the mouthpiece. The interior of the angle for each round hole may be open towards the first rotational direction. Each inlet of the second plurality of air inlets may also be a round hole that passes through a certain thickness of the mouthpiece and forms an angle of about 15 degrees to 45 degrees with the outer surface of the mouthpiece. The interior of the angle for each round hole of the second plurality of air inlets may be open towards the second rotational direction. The first rotational direction and the second direction may be opposite directions. For example, the first rotational direction may be counterclockwise and the second rotational direction is clockwise. The first rotational axis and the second rotational axis may not be parallel. The first plurality of air inlets and the second plurality of air inlets may provide a turbulent mixing of the inlet air and the vapor entering the mouthpiece from the vapor inlet. The first plurality of air inlets and the second plurality of air inlets may be arranged in a plane. The first plurality of air inlets and the second plurality of air inlets may each be arranged in a circular pattern. The cross-sectional area of the vapor inlet may be at least four times the cross-sectional area of the aerosol outlet. The vapor inlet may have a vapor inlet temperature and the aerosol outlet has an aerosol outlet temperature, and the difference between the vapor inlet temperature and the aerosol outlet temperature may be at least 100 °C. A solid evaporable material may be included in the evaporator device. The solid evaporable material may be a medium containing tobacco. The evaporator device may include an input terminal configured to electrically connect a power source to the PTCR heating element in response to a user input. The input terminal may include a button. The evaporator device may not include a controller. The evaporator device may not include a pressure sensor. In another aspect, the evaporator device includes a pressure sensor and a controller, the controller being coupled to the pressure sensor and configured to detect inhalation and, in response, electrically connect the power source to the PTCR heating element. The heat exchanger may include a first heat exchanger thermally coupled to the first side of the heating element. The heat exchanger may include a second heat exchanger thermally coupled to the second side of the heating element. The heat exchanger may include a plurality of fin features. The heat exchanger may be made of aluminum, copper, steel, stainless steel or titanium. The heat exchanger may be extruded from a thermally conductive material. The heat exchanger may be made of metal foam, such as aluminum foam. The PTCR heater assembly may include a heater assembly cover. The heater assembly cover may include a non-conductive material. The heater assembly cover may include a non-thermally conductive material. The heater assembly cover may include a metal with a non-conductive coating that isolates the heater assembly cover from the heat exchanger. The heater assembly cover may contain polytetrafluoroethylene (PTFE).

[0019] The resistivity transition region can start at a first temperature between 150 °C and 350 °C. The resistivity transition region can also start at a first temperature between 220 °C and 300 °C. The resistivity transition region can also start at a first temperature between 240 °C and 280 °C. The first temperature can be greater than 225 °C. The PTCR heating element can be heated to an operating temperature between 240 °C and 280 °C. The PTCR heating element can be heated to an operating temperature between 245 °C and 255 °C. The PTCR heating element can be heated to an operating temperature of about 250 °C. The PTCR heater assembly can increase the resistivity by an increase factor of at least 10, at least 100, or at least 1000 within the temperature range of the resistivity transition region. The increase factor characterizes the relative change in resistivity between the resistivity at a first temperature associated with the start of the resistivity transition region and the resistivity at a second temperature associated with the end of the resistivity transition region. The resistivity transition region can start at a first temperature and end at a second temperature, where the difference between the first temperature and the second temperature is 500 °C or less, 200 °C or less, 100 °C or less, or 50 °C or less. The resistivity transition region can start at a first temperature and the resistivity of the PTCR heating element at a temperature below the first temperature can be between 0.2 ohm-cm and 2.0 ohm-cm, between 2.0 ohm-cm and 20 ohm-cm, or between 20 ohm-cm and 200 ohm-cm.

[0020] In another aspect, a method of evaporating an evaporable material includes receiving user input through an evaporator device and heating an air stream using a PTCR heater assembly to produce a heated air stream, the PTCR heater assembly including a heat exchanger thermally coupled to a PTCR heating element. The PTCR heating element is configured to be electrically coupled to a power source. The PTCR heating element includes a resistivity that varies based on temperature. The resistivity includes a resistivity transition region that includes an increase in resistivity within a temperature range from a first temperature to a second temperature such that when the PTCR heating element is heated between the first temperature and the second temperature, the current from the power source is reduced to a level that limits further temperature rise of the PTCR heating element due to the current. The method further includes evaporating the evaporable material with the heated air stream. The evaporable material can include nicotine.

[0021] Details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the following description. Other features and advantages of the subject matter described herein will become more apparent from the specification and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Illustrates the thermogeneration behavior within an isotropic PTCR material;

[0023] Figure 2is a block diagram showing an exemplary evaporator device in accordance with some embodiments of the present subject matter, which can utilize convective heating to provide uniform heating of an evaporable material;

[0024] Figure 3 is a block diagram of an exemplary evaporator device and a cartridge having a liquid evaporable material, which can utilize convective heating to provide uniform heating of the evaporable material;

[0025] Figure 4 is a cross-sectional view of an exemplary evaporator device having a liquid evaporable material.

[0026] Figure 5 is a cross-sectional view of an exemplary evaporator device having a solid evaporable material (e.g., a heat-not-burn product);

[0027] Figure 6 is a block diagram of an exemplary evaporator device and a cartridge having a liquid evaporable material and a solid evaporable material, which can utilize convective heating to provide uniform heating of the evaporable material;

[0028] Figure 7 is a block diagram of an exemplary evaporator device having multiple cartridges;

[0029] Figure 8 is a cross-sectional view of an exemplary evaporator device having both a liquid evaporable material and a solid evaporable material.

[0030] Figure 9 is a graph illustrating an exemplary resistivity-versus-temperature curve of a non-linear positive resistivity temperature coefficient (PTCR) material;

[0031] Figure 10 presents Figure 9 a table of resistivity-versus-temperature curve data for the non-linear PTCR semiconductor material shown;

[0032] Figure 11 is a graph illustrating an exemplary resistivity-versus-temperature curve of a non-linear positive resistivity temperature coefficient (PTCR) material;

[0033] Figure 12A is a diagram showing an exemplary PTCR heating element capable of improving evaporator heating;

[0034] Figure 12B is Figure 12A a cross-section of the exemplary PTCR heating element shown;

[0035] Figures 13A to 13E shows the modeled temperature of an exemplary PTCR heater;

[0036] Figures 14A to 14FShows the modeled temperature of an exemplary PTCR heater;

[0037] Figure 15 Shows the modeled temperature of an exemplary heater after applying voltage for 6.0 seconds in a free convection state;

[0038] Figure 16A Shows the modeled surface temperature of an exemplary heater as a function of time;

[0039] Figure 16B Shows the modeled and measured maximum surface temperature of an exemplary heater as a function of time;

[0040] Figure 16C Shows the modeled and measured average surface temperature of an exemplary heater as a function of time;

[0041] Figure 17 Shows the transient current response of an exemplary heater as a function of time;

[0042] Figure 18 Is a perspective view of an exemplary evaporator assembly, which includes a PTCR heater and a heat exchanger element capable of achieving convective heating and improving the uniform heating of the evaporable material;

[0043] Figure 19 Is an exploded view of a rectangular PTCR evaporation device, including an exploded view of an exemplary evaporator assembly;

[0044] Figure 20 Is a perspective view of an exemplary PTCR evaporation assembly;

[0045] Figure 21 Is a perspective view of an exemplary PTCR evaporation assembly and a disposable rectangular product;

[0046] Figure 22 Is a perspective view of an exemplary PTCR evaporation assembly and a disposable rectangular product after activation for 0.2 seconds;

[0047] Figure 23 Is a perspective view of an exemplary PTCR evaporation assembly and a disposable rectangular product after activation for 0.5 seconds;

[0048] Figure 24 Is a perspective view of an exemplary PTCR evaporation assembly and a disposable rectangular product after activation for 1.0 second;

[0049] Figure 25 Is a perspective view of an exemplary PTCR evaporation assembly and a disposable rectangular product after activation for 2.0 seconds;

[0050] Figure 26Is a perspective view of an exemplary PTCR evaporation assembly and a disposable rectangular product after 3.0 seconds of activation;

[0051] Figure 27 Is a perspective view of an exemplary PTCR heater having a cylindrical geometry;

[0052] Figure 28 Is an exploded view showing a cylindrical exemplary PTCR heater;

[0053] Figure 29 Is a perspective view of an exemplary assembled PTCR heater;

[0054] Figure 30 Is a perspective view of an exemplary PTCR evaporation device with the outer cover and cylindrical diverter removed;

[0055] Figure 31 Is a perspective view of an exemplary PTCR evaporation device;

[0056] Figure 32 Is a graph showing the variation of the logarithm of resistivity with temperature for a cylindrical exemplary evaporation device having a PTCR heater;

[0057] Figure 33 Is a cross-sectional view showing the temperature simulation of an exemplary embodiment of a cylindrical evaporation device having a PTCR heater;

[0058] Figures 34A to 34G Is a shear diagram showing the transient response of temperature as color for an exemplary embodiment of a cylindrical evaporation device having a PTCR heater;

[0059] Figure 35 Shows a perspective view and an end view of a nozzle including a plurality of air inlets;

[0060] Figure 36 Is a perspective view of a nozzle attached to a PTCR rectangular evaporation assembly;

[0061] Figure 37 Is a perspective view of a nozzle attached to a PTCR rectangular evaporation assembly, showing the air flow and temperature field pattern without an active air inlet;

[0062] Figure 38 Is a transparent end view observed through the aerosol outlet of a nozzle including a plurality of air inlets, showing the air flow field pattern;

[0063] Figure 39 Is a perspective view of a nozzle attached to a PTCR rectangular evaporation assembly, showing the air flow and temperature field pattern after 0.1 second of activation;

[0064] Figure 40is a perspective view of a nozzle attached to a PTCR rectangular evaporation module, showing the air flow and temperature field patterns after 0.2 seconds of activation;

[0065] Figure 41 is a perspective view of a nozzle attached to a PTCR rectangular evaporation module, showing the air flow and temperature field patterns after 0.3 seconds of activation;

[0066] Figure 42 is a perspective view of a nozzle attached to a PTCR rectangular evaporation module, showing the air flow and temperature field patterns after 0.4 seconds of activation;

[0067] Figure 43 is a perspective view of a nozzle attached to a PTCR rectangular evaporation module, showing the air flow and temperature field patterns after 0.5 seconds of activation;

[0068] Figure 44 is a perspective view of a nozzle attached to a PTCR rectangular evaporation module, showing the air flow and temperature field patterns after 1.0 second of activation;

[0069] Figure 45 is a perspective view of a nozzle attached to a PTCR rectangular evaporation module, showing the air flow and temperature field patterns after 2.0 seconds of activation;

[0070] Figure 46 is a perspective view of a nozzle attached to a PTCR rectangular evaporation module, showing the air flow and temperature field patterns after 3.0 seconds of activation;

[0071] Figure 47 illustrates the air temperature exiting the nozzle as a function of time for an exemplary evaporator device including a PTCR heater;

[0072] Figure 48 illustrates the current response as a function of time for an exemplary evaporator device including a PTCR heater; and

[0073] Figure 49 is a top view of a nozzle attached to a PTCR rectangular evaporation module, showing the differential current density within the PTCR heater in response to the cold ambient air flow entering the PTCR heater module.

[0074] Like reference numerals in the figures indicate like elements where possible. DETAILED DESCRIPTION

[0075] Some aspects of the present subject matter relate to an evaporator heater that utilizes a non-linear positive resistivity temperature coefficient (PTCR) heating element (also referred to as a PTCR heater) as a convection heater. In such a convection heater for an evaporator, air is heated by the heating element and passes over or through an evaporable material to form a vapor and / or aerosol for inhalation. In an embodiment, the evaporable material can include a solid evaporable material (e.g., loose tobacco leaf material commonly used in heat-not-burn (HNB) evaporators) and / or a liquid evaporable material (e.g., pre-filled cartridges / cartomizers, pods, and the like). The PTCR heating element for convective heating can result in more uniform heating of the evaporable material. Improving heating uniformity can provide a number of advantages, including avoiding temperature differences within the evaporable material that act as insulators, preventing contamination of the heating element, and the like. And because the heating element can be formed from a PTCR material, the heating element can be self-limiting in temperature and will not heat above a specific temperature within a known applied voltage range, thereby avoiding the formation of unwanted and potentially dangerous chemical by-products.

[0076] Thermogeneration within an isotropic PTCR material is characterized in that for each control volume within the isotropic PTCR material that is subject to a voltage gradient the control volume control volume will be heated to a temperature within the PTCR transition region and maintained at within a wide range, as Figure 1 shown. Thermogeneration can be expressed as: where P is the thermogeneration, vol is the control volume (e.g., ), and ρ is the resistivity.

[0077] By utilizing a PTCR heating element, some embodiments can have the temperature controlled within the applied voltage range and do not require a temperature sensor, an electronic circuit, a microprocessor, and / or an algorithm to provide power control to the heating element.

[0078] As used herein, the term solid vaporizable material generally refers to a vaporizable material that includes a solid material. For example, some evaporator devices heat materials derived from plant leaves or other plant components to extract aromatic agents and other products with specific plant flavors as vapors. These plant materials can be chopped and mixed with a variety of plant products that may include tobacco into a homogenized structure, in which case nicotine and / or nicotine compounds can be produced and delivered to the user of such an evaporator device in the form of an aerosol. The homogenized structure can also include vaporizable liquids such as propylene glycol and glycerol to increase the vapor density and aerosol produced upon heating. To avoid generating unwanted harmful or potentially harmful components (HPHCs), this type of evaporator device benefits from having a heater with temperature control measures. An evaporator device that heats plant leaves or the homogenized structure as described above such that the temperature is kept below the combustion level is generally referred to as a heat-not-burn (HNB) device.

[0079] As used herein, the term liquid vaporizable material generally refers to a vaporizable material that does not include a solid material. Liquid vaporizable materials can include, for example, liquids, solutions, waxes, or any other form that is compatible with the use of a particular evaporator device. In an embodiment, the liquid vaporizable material can include any form suitable for using a wick or wicking element to draw the vaporizable material into an evaporation chamber. Liquid vaporizable materials can include components of plant origin such as nicotine and / or nicotine compounds. Liquid vaporizable materials can include vaporizable liquids such as propylene glycol and glycerol.

[0080] An evaporator device operates in such a way that it heats the vaporizable material to a suitable temperature to produce an aerosol, but does not cause the vaporizable material to burn or carbonize. One class of evaporator devices is more complex because it utilizes relatively strict temperature control to prevent overheating and the formation of associated HPHCs. Due to the inherent non-uniformity of the vaporizable material to be heated and the associated spatially inconsistent thermal characteristics, this complexity typically requires an electronic circuit that includes a microprocessor, which is generally difficult in HNB devices. This can result in over-temperature regions and the potential generation of HPHCs. And some existing solutions cannot control the local temperature within the evaporator device, leading to a high likelihood of the generation of vaporizable material and HPHCs in the over-temperature regions.

[0081] Another class of evaporator devices is simpler because no temperature control measures are provided, making the construction of the evaporator device potentially cheaper but including the risk of overheating and thereby resulting in unwanted chemical by-products.

[0082] In an HNB evaporator device (e.g., where the evaporable material is a solid), some existing methods lack the ability to apply a uniform temperature due to one or more of the following reasons. For example, the solid evaporable material to be heated has a low thermal diffusivity, such that the diffusion of high temperature from the heating element into the solid evaporable material is both slow and results in a high thermal gradient. As a result, non-uniform heating may be an inevitable outcome. As another example, if heating element temperature control is employed, the heating element temperature control typically deals with the average temperature, such that heating a non-uniform solid evaporable material by the high temperature within the heating element can lead to high temperatures within the solid evaporable material. As yet another example, in order to allow heating of the insulating material, some existing HNB devices require a preheating time equal to or exceeding 30 seconds, along with costs in terms of energy consumption, battery consumption, and user inconvenience.

[0083] In an evaporator device that evaporates a fluid by bringing a heating element into contact with the fluid to be evaporated, contamination of the heating element may occur, which can lead to performance degradation. A solution to this problem can be to incorporate the heating element into a disposable part of the evaporator, such that the heating element is replaced by each new disposable part, thereby limiting but not eliminating contamination of the heating element.

[0084] To overcome the difficulty of uniformly heating the evaporable material, some embodiments of the present subject matter may be configured to use one or more PTCR heating elements in combination with a heat exchanger to preheat air. When the user inhales air into the evaporator device, the incoming air stream is heated to a controlled temperature as it passes through the heat exchanger and then passes through or over the evaporable material to be heated. The evaporable material can be a solid material (e.g., as in HNB material) or a liquid (e.g., a fluid together with a porous wick). In an embodiment, the air stream can pass through the heat exchanger, then through and / or over a porous wick filled with the liquid evaporable material, then through the solid evaporable material (e.g., HNB material), and then reach the user. In an embodiment, the geometry for cooling the incoming air can be included between the wick and the user, such as a balanced air inlet (i.e., a second air inlet). Additionally, the present subject matter can provide a PTCR heater with inherent temperature control, e.g., for a given range of power supply voltages (which can vary by a factor of ten or more in some embodiments), the designed peak temperature will not be exceeded. Compared with some traditional methods, this method can result in improved uniform heating of the evaporable material.

[0085] Furthermore, using this convective heating method, the PTCR heating element can be placed upstream of the wick, the fluid container, and / or the evaporable material, such that the PTCR heating element can be completely removed from any disposable part of the mechanism. By including the PTCR heating element in the non-disposable part of the evaporator device, unnecessary waste can be avoided.

[0086] Figure 2 FIG. 2 is a block diagram showing an exemplary evaporator device 100 according to some embodiments of the present subject matter, which can provide uniform heating to an evaporable material using convective heating. The exemplary evaporator device 100 includes an air inlet 105, a PTCR heater 110 with a heat exchanger, and a power source 115, such as a battery, a capacitor, and / or the like. The exemplary evaporator device 100 may include a housing 120, which may be coupled to one or more of the PTCR heater 110 with a heat exchanger and the power source 115. In an embodiment, the exemplary evaporator device 100 may include an optional controller 102 and an optional pressure sensor 107. In an embodiment, the housing 120 may define the air inlet 105.

[0087] The PTCR heater 110 with a heat exchanger may include a heating element formed of a PTCR material, which will be described in more detail below. The heat exchanger may be thermally coupled to the heating element and may be configured to transfer heat between the heating element and an air flow passing through and / or across the PTCR heater 110 with a heat exchanger to generate a heated air flow. The PTCR heater 110 with a heat exchanger may include a plurality of heat exchangers, for example, coupled to different sides of the heating element, and may include splitters for splitting the air flow through and / or over the fins of the heat exchanger to improve heat transfer. Reference is made below Figures 9 to 34G to a more detailed discussion of an exemplary PTCR heater 110 with a heat exchanger.

[0088] The exemplary evaporator device 100 may include a connector 117 ( Figure 4 , Figure 5 and Figure 8 as shown in FIGS. 3A-3C), for coupling the housing 120 to one or more cartridges 125 including an evaporable material 130. In an embodiment, the cartridge 125 may include a mouthpiece 135. In an embodiment, the coupling may be releasable such that a user can easily couple and decouple the cartridge 125 from the evaporator device 100 through the connector 117.

[0089] When the evaporator device 100 is coupled to the cartridge 125, the evaporator device 100 and the cartridge 125 may be arranged to define an air flow path from the air inlet 105, through and / or over the PTCR heater 110 with a heat exchanger, through a first air inlet of the cartridge, through the evaporable material 130, and out through the mouthpiece 135.

[0090] An optional controller 102 (e.g., a processor, circuitry, etc. capable of performing logic) is used to control the transfer of heat such that an evaporable material is converted from a condensed form (e.g., solid, liquid, solution, suspension, a portion of at least partially unprocessed plant material, etc.) to a gaseous phase. The optional controller can be part of one or more printed circuit boards (PCBs) consistent with certain embodiments of the present subject matter.

[0091] Power source 115 can include any power source suitable for applying power to the PTCR heater 110 with a heat exchanger. For example, power source 115 can include a battery, a capacitor (even with a resistor-capacitor (RC) decay), and / or the like. In an embodiment, power source 115 can provide a voltage selectable from a wide range of voltages. For example, in some embodiments, power source 115 can provide a voltage between 3 volts and 50 volts or higher. In an embodiment, the voltage provided to the PTCR heater 110 with a heat exchanger can vary by an order of magnitude with little effect on the performance of the PTCR heater 110 with a heat exchanger. In an embodiment, power source 115 can include multiple power sources, which can be selected based on operating conditions and / or desired evaporator device performance.

[0092] In operation, a user can inhale air through the mouthpiece 135 (e.g., by sucking), which can be detected by the optional controller 102 using the optional pressure sensor 107. In response to detecting the suck, the optional controller 102 can cause current from the power source 115 to be applied to the PTCR heater 110 with a heat exchanger, thereby heating up the PTCR heater 110 with a heat exchanger. Since the PTCR heater 110 with a heat exchanger is formed of a PTCR material, the heating will be self-limiting and the heating element will not overheat.

[0093] The air flow passes through the air inlet 105 and over and / or through the PTCR heater 110 with a heat exchanger, uniformly heating the air in the air flow. The heated air flow continues to reach the evaporable material 130, uniformly heating the evaporable material 130 as well and forming a vapor (gas). The evaporable material 130 can include a liquid, a solution, a solid, a wax, or any other form. In an embodiment, the incoming air passing along the air flow path passes over, through, and in a similar manner past a region or chamber (e.g., an atomizer) in which the gaseous-phase evaporable material is entrained into the air.

[0094] The entrained vaporizable material may condense as it passes through the remainder of the airflow path such that an inhalable dose of the vaporizable material in aerosol form may be delivered to the mouthpiece 135 for inhalation by the user in the form of vapor and / or aerosol. In an embodiment, the cartridge 125 includes a balance air inlet (i.e., a second air inlet) 140 that may be used to provide ambient temperature air to mix with the heated airflow entering the cartridge through the first air inlet. The ambient temperature air may be mixed with the heated airflow in the condensation chamber. The balance air inlet 140 is positioned downstream of the heated airflow passing through the vaporizable material (e.g., downstream of the heat exchanger and the vaporizable material) to cool the heated airflow prior to user inhalation. In an embodiment, the balance air inlet 140 is integrated with the mouthpiece 135.

[0095] Activation of the PTCR heating element may be caused by an automatically detected puff based on one or more signals generated by one or more sensors, such as an optional pressure sensor 107 or a sensor configured to detect a change in pressure along the airflow path relative to ambient pressure (or optionally measure absolute pressure), one or more motion sensors of the evaporator, one or more flow sensors of the evaporator, a capacitive lip sensor of the evaporator; receiving a signal from a computing device in communication with the evaporator in response to detecting user interaction with one or more input devices (e.g., a button or other tactile control device of the evaporator, such as a manual toggle switch, pushbutton switch, pressure switch, etc.); and / or by other means of determining that a puff is occurring or about to occur.

[0096] As mentioned in the previous paragraph, an evaporator consistent with embodiments of the present subject matter may be configured to connect (e.g., wirelessly or by a wired connection) to a computing device (or optionally two or more devices) in communication with the evaporator. To this end, the optional controller 102 may include communication hardware. The optional controller 102 may also include a memory. The computing device may be a component of an evaporator system that also includes the evaporator, and the computing device may include its own communication hardware that may establish a wireless communication channel with the communication hardware of the evaporator. For example, a computing device used as part of an evaporator system may include a general computing device (e.g., a smartphone, a tablet computer, a personal computer, some other portable device, such as a smartwatch, etc.) that executes software to generate a user interface such that a user of the device may interact with the evaporator. In other embodiments of the present subject matter, such a device used as part of an evaporator system may be dedicated hardware, such as a remote control or other wireless or wired device having one or more physical or software interface controls (e.g., configurable on a screen or other display device and may be actuated by user interaction with a touch-sensitive screen or some other input device, such as a mouse, pointer, trackball, cursor button, etc.). The evaporator may also include one or more output features or devices for providing information to the user.

[0097] A computing device that is part of an evaporator system as defined above can be used for any one of one or more functions, such as dose control (e.g., dose monitoring, dose setting, dose limiting, user tracking, etc.), session control (e.g., session monitoring, session setting, session limiting, user tracking, etc.), nicotine delivery control (e.g., switching between nicotine and non-nicotine vaporizable materials, adjusting the amount of nicotine delivered, etc.), obtaining location information (e.g., the location of other users, retailer / commercial establishment locations, e-cigarette use locations, relative or absolute location of the evaporator itself, etc.), evaporator personalization (e.g., naming the evaporator, locking / password protecting the evaporator, adjusting one or more parental controls, associating the evaporator with a user group, registering the evaporator with a manufacturer or warranty maintenance organization, etc.), engaging in social activities with other users (e.g., games, social media communication, interacting with one or more groups, etc.), etc. The terms "conducting a session", "session", "evaporator session", or "vaping session" are generically used to refer to a period of time dedicated to using the evaporator. This period can include time intervals, number of doses, amount of vaporizable material, etc.

[0098] In an example where the computing device provides a signal related to the activation of a PTCR heating element, or in other examples where the computing device is coupled to the evaporator to enable various controls or other functions, the computing device executes one or more sets of computer instructions to provide a user interface and underlying data processing. In one example, the detection by the computing device of a user's interaction with one or more user interface elements can cause the computing device to signal the evaporator to activate the PTCR heating element to a full operating temperature for generating an inhalable dose of vapor / aerosol. Other functions of the evaporator can be controlled by the user's interaction with a user interface on the computing device that communicates with the evaporator.

[0099] The temperature of the PTCR heating element of the evaporator can depend on a variety of factors, including conductive heat transfer to other parts of the electronic evaporator and / or the environment, latent heat loss due to evaporation of the evaporable material from the wicking element and / or atomizer as a whole, and convective heat loss due to air flow (e.g., when a user inhales on the electronic evaporator, air moves through the heating element or atomizer as a whole). As described above, in order to reliably activate the PTCR heating element or heat the PTCR heating element to a desired temperature, in some embodiments of the present subject matter, the evaporator can utilize a signal from an optional pressure sensor 107 to determine when the user inhales. The optional pressure sensor 107 can be positioned in the air flow path and / or can be connected (e.g., via a passage or other path) to the air flow path that connects the air inlet 105 (which allows air to enter the device) and the outlet (e.g., in the mouthpiece 135), through which the user inhales the generated vapor and / or aerosol, such that the optional pressure sensor experiences a pressure change while air passes from the air inlet 105 through the evaporator device to the air outlet. In embodiments of the present subject matter, the PTCR heating element can optionally be activated in association with the user's draw, e.g., by automatically detecting the draw, e.g., by detecting a pressure change in the air flow path by the optional pressure sensor 107. In an embodiment, a switch is an input device that can be used to electrically complete the circuit between the power source and the PTCR heating element. In an embodiment, the input device includes a relay, solenoid, and / or solid state device that can be used to electrically complete the circuit between the power source and the PTCR heating element to activate the evaporator device.

[0100] Typically, the optional pressure sensor 107 (and any other sensors) can be located on or coupled to (e.g., electrically connected or electronically connected, physically connected or wirelessly connected) the optional controller 102 (e.g., a printed circuit board assembly or other type of circuit board). To accurately measure and maintain the durability of the evaporator, it is beneficial to provide a resilient seal to separate the airflow path from other parts of the evaporator. The seal (which can be a gasket) can be configured to at least partially surround the optional pressure sensor 107 such that the connection of the optional pressure sensor 107 to the internal circuitry of the evaporator is separated from the portion of the optional pressure sensor 107 that is exposed to the airflow path. In an example of a cartridge-based evaporator, the seal or gasket can also separate portions of one or more electrical connections between the evaporator body and the evaporator cartridge. This arrangement of gaskets or seals in the evaporator can help mitigate potential damaging effects on evaporator components due to interaction with environmental factors (such as water in the vapor or liquid phase, other fluids (such as evaporable materials, etc.)), and / or reduce air leakage from the designed airflow path in the evaporator. Unwanted air, liquid, or other fluids passing through and / or contacting the circuitry of the evaporator can cause various undesirable effects, such as altering pressure readings, and / or may cause unwanted materials (such as moisture), evaporable materials, etc. to accumulate in various parts of the evaporator, where the unwanted materials, evaporable materials, etc. may cause poor pressure signals, degradation of the optional pressure sensor or other components, and / or a shortened lifespan of the evaporator. Leakage in the seal or gasket can also cause the user to inhale air that has passed through parts of the evaporator device that contain or are composed of materials that may not be suitable for inhalation.

[0101] In an embodiment, the cartridge 125 can include a fibrous body for cooling the heated airflow after it passes through the evaporable material 130.

[0102] As described above, the evaporable material 130 can include a solid evaporable material (e.g., an HNB material) and / or a liquid evaporable material (e.g., a liquid, a solution, etc.). Figure 3is a block diagram of an exemplary evaporator device 100 and a cartridge 125 having a liquid evaporable material, which can provide uniform heating to the evaporable material using convective heating. The evaporable material 130 includes an atomizer that includes a porous wick 150 in fluid communication with a fluid tank or reservoir 145. The porous wick 150 is located within the path of the heated air flow between the PTCR heater 110 with a heat exchanger and the mouthpiece 135. The porous wick 150 is positioned such that during operation the heated air flow passes over and / or through the porous wick 150, the porous wick 150 is saturated with the evaporable fluid, and the liquid evaporable material filling the porous wick 150 evaporates to form a vapor and / or an aerosol. In an embodiment, the porous wick 150 may allow air to enter the reservoir 145 to replace the removed liquid volume. In other words, capillary action draws the liquid evaporable material into the wick 150 to be evaporated by the heated air flow, and in some embodiments of the present subject matter, air may return through the wick to the reservoir 145 to at least partially balance the pressure in the reservoir 145. Other methods of allowing air to return to the reservoir 145 to balance the pressure are also within the scope of the present subject matter. Figure 4 is a cross-sectional view of an exemplary evaporator device having a liquid evaporable material, and Figure 5 is a cross-sectional view of an exemplary evaporator device having a solid evaporable material (e.g., an HNB product).

[0103] In an embodiment, the evaporable material 130 may include both a liquid evaporable material and a solid evaporable material. For example, Figure 6 is a block diagram of an exemplary evaporator device 100 and a cartridge 125 having a liquid evaporable material and a solid evaporable material, which can provide uniform heating to the evaporable material using convective heating. The evaporable material 130 includes a reservoir 145 that houses a liquid evaporable material; a wick 150 in fluid communication with the liquid evaporable material and a solid evaporable material 155 downstream (with respect to the air flow) of the porous wick 150. The porous wick 150 is arranged to receive a heated air flow from the heater 110 with a heat exchanger to evaporate the evaporable material to produce a vapor and / or a first aerosol. The solid evaporable material 155 is arranged to receive the vapor and / or the first aerosol from the wick and produce a second aerosol. The mouthpiece 135 is configured to receive the second aerosol after the evaporated evaporable material has passed through the solid evaporable material 155. By combining both a liquid evaporable material and a solid evaporable material, an improved flavor can be achieved. In addition, by using convective heating via a PTCR material to evaporate both the liquid evaporable material and the solid evaporable material, only a single heater is required to heat both materials.

[0104] In an embodiment, the liquid evaporable material and the solid evaporable material may be included in different cartridges. For example,Figure 7 is a block diagram of an exemplary evaporator device 100 with multiple cartridges. The first cartridge 605 includes a liquid evaporable material (including a reservoir 145 and a porous wick 150), while the second cartridge 610 includes a solid evaporable material 130, which can provide uniform heating for the evaporable material using convective heating. The first cartridge 605 can be detachably coupled to the evaporator device 100 and the second cartridge 610 can be detachably coupled to the first cartridge 605. As shown, the first cartridge 605 includes a reservoir 145 (e.g., a tank), the liquid evaporable material within the reservoir 145, and a wick 150 in fluid communication with the liquid evaporable material. When the first cartridge 605 is coupled to the evaporator device 100, the wick 150 is arranged to receive a heated air stream from a heater 110 with a heat exchanger to evaporate the evaporable material to produce vapor and / or a first aerosol. The second cartridge 610 includes a solid evaporable material 130, a balanced air inlet 140, and a mouthpiece 135. When the second cartridge 610 is coupled to the first cartridge, the solid evaporable material 130 is arranged to receive the vapor and / or aerosol from the wick 150 and produce a second aerosol. The mouthpiece 135 is configured to receive the second aerosol after the vapor and / or the first aerosol has passed through the solid evaporable material 155. In an embodiment, the balanced air inlet (i.e., the second air inlet) 140 can provide ambient temperature air for cooling the heated first aerosol that has passed through the solid evaporable material 155. Figure 8 is a cross-sectional view of an exemplary evaporator device with both a liquid evaporable material and a solid evaporable material.

[0105] Compared to conventional conduction heating methods, this convective heating method can provide several advantages for evaporating solid materials (e.g., HNB materials). For example, instead of poorly conducting orthogonally to the air flow direction into an insulating material (e.g., the solid evaporable material), creating volatiles and differential porosity of the evaporable material to be heated, some embodiments of the present subject matter can provide incoming preheated air that uniformly enters the evaporable material as a ripple uniformly covering the cross-section of the evaporable material. The volatiles are then released in a direction parallel to the heated air flow while the porosity increases. As another example, due to the uniform cross-sectional release of volatiles and the simultaneous increase in porosity, the problem of differential flow paths can be eliminated in some embodiments. As yet another example, the problem of deterioration of conductive heat transfer through the product can be eliminated in some embodiments of the present subject matter. As yet another example, the need for a prior preheating period can be eliminated in some embodiments of the present subject matter, such that the present subject matter can provide an aerosol on demand from the heated evaporable material.

[0106] Similarly, this convective heating method can offer several advantages for evaporating a liquid vaporizable material. For example, instead of applying heat directly to the liquid vaporizable material using a heating element in direct contact with the liquid vaporizable material, some embodiments of the present subject matter can provide incoming preheated air that acts as a ripple uniformly covering the cross-section of a porous wick saturated with the fluid to be evaporated, thereby avoiding potential temperature differences and heating element contamination.

[0107] As another example, by placing the wick near and upstream (with respect to the air flow) of a solid vaporizable material (e.g., loose tobacco leaves), undesired aerosol condensation within the device can be minimized.

[0108] Furthermore, since no specific thermal feedback is required, the inherent temperature control behavior of a PTCR heater can simplify the power delivery circuit. By eliminating the need for a typical power delivery system that provides a relatively constant voltage to the power source, the power transmission circuit to the PTCR heater can be further simplified. In an embodiment, the applied voltage can vary by more than an order of magnitude without significantly affecting the temperature of the resulting heating element.

[0109] Exemplary PTCR heaters will now be described in more detail. A PTCR includes a semiconductor material having a resistivity that varies non-linearly with increasing temperature. A typical PTCR material has a relatively low resistivity when the temperature is maintained below a temperature transition region. Above the temperature transition region, the resistivity of the PTCR material is higher than that of the same PTCR material at a temperature below the temperature transition region. Within a temperature transition region of 50 degrees Celsius or less, the resistivity change can increase by several orders of magnitude.

[0110] The heating element can utilize the non-linear PTCR material to achieve inherent temperature control. For example, a heating element at ambient temperature can be connected to a power source that provides a voltage gradient and resulting current. Since the resistivity of the heating element is relatively low at ambient temperature (e.g., ambient temperature is below the transition region), current will flow through the heating element. When current flows through the non-linear PTCR material, resistance generates heat (e.g., dissipation of electrical energy). The heat generated causes the temperature of the heating element to increase, thereby changing the resistivity of the heating element. When the temperature of the heating element reaches the transition region, the resistivity increases significantly within a small temperature range. The change in resistivity can be caused by the physical properties of the material. For example, a phase change may occur in the material. This increase in resistivity (resulting in an overall increase in resistance) reduces the current, thereby reducing the heat generation. The transition region includes a temperature at which there is an inflection point such that the heat generated is not sufficient to further raise the temperature of the heating element, thereby limiting the temperature of the heating element. As long as the power source remains connected and supplies current, the heating element will maintain a uniform temperature with minimal temperature variation. In this case, the power applied to the PTCR heating element can be given by the formula PI = voltage 2 / resistance. The heat loss of the PTCR heating element can be represented by P L and includes any combination of conduction, convection, radiation, and latent heat. During steady-state operation, P I = P L . As P L increases, the temperature of the PTCR heating element decreases, thus reducing the resistance, and thus increasing the current flowing through the PTCR heating element. As P L decreases, the temperature of the PTCR heating element increases, thus increasing the resistance, and thus reducing the current flowing through the PTCR heating element. When P L approaches 0, the resistance of the PTCR heating element increases logarithmically. The limited operating temperature of the PTCR heating element may be affected by factors such as the element material, element geometry, element resistivity as a function of temperature characteristics, power supply, circuit characteristics (such as voltage gradient, current, time-varying characteristics), etc.

[0111] Figure 9 is a graph showing an exemplary resistivity versus temperature curve of a nonlinear PTCR material. The vertical axis is logarithmic. A heating element (referred to as a PTCR heater) composed of (e.g., formed from) a nonlinear PTCR material can have advantageous characteristics. For example, when a sufficient voltage gradient (e.g., ) is applied, the PTCR heater will generate heat and increase the temperature until it reaches the transition region. In the Figure 9 shown curve, the transition region spans between temperatures T1 and T2. In the Figure 9 shown curve, the resistivity versus temperature curve is nonlinear between T1 and T2, but in other embodiments, the resistivity versus temperature curve can be close to linear or linear or other shapes. At some temperatures above T1, the resistivity of the nonlinear PTCR material will increase to a point where further temperature increase will stop because the total resistance will increase to a point that limits the current. In other words, the implementation of the PTCR heater can be considered temperature self-limiting, and within a known range of a given applied voltage, it will not heat above a temperature just above the low point T1 of the temperature transition region.

[0112] The performance of the PTCR heater can depend on Figure 9PTCR behavior and heater geometry in. A PTCR heater having a relatively long and narrow geometry and having electrical contacts for applying a differential voltage at each end of the longer dimension of the PTCR heater may be ineffective because the resistivity of the non-linear PTCR material is typically too high at temperatures below T1. A non-linear PTCR material having a steep transition region (where the temperature difference between T1 and T2 is less than 10 °C) may cause all voltages to drop within a small fraction of the length of the long and narrow geometry and give an inevitable spatial non-uniformity within any material. Accordingly, some embodiments of the PTCR heater include an electrode configuration for the PTCR heater such that the non-linear PTCR material is provided within a parallel circuit. In some embodiments where improved heating uniformity can be provided, the geometry of the PTCR heater may include a thin section of non-linear PTCR material sandwiched between electrical conductors or conductive coatings to which a differential voltage can be applied.

[0113] Figure 10 Presents for Figure 9Table of resistivity versus temperature curve data for the nonlinear PTCR semiconductor material shown in [figure reference]. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 100 ohm-cm at 100 °C and a resistivity between 50,000 ohm-cm and 150,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 20 ohm-cm and 200 ohm-cm at 100 °C and a resistivity between 100,000 ohm-cm and 200,000 ohm-cm at 265 °C. In an embodiment, the PTCR heating element has a resistivity less than 100 ohm-cm at 100 °C and a resistivity greater than 100,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity less than 100 ohm-cm at 100 °C and a resistivity greater than 250,000 ohm-cm at 275 °C. In an embodiment, the PTCR heating element has a resistivity less than 100 ohm-cm at 100 °C and a resistivity greater than 300,000 ohm-cm at 295 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 110 ohm-cm at 25 °C, a resistivity between 10 ohm-cm and 110 ohm-cm at 100 °C, and a resistivity between 100,000 ohm-cm and 325,000 ohm-cm at 280 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 150 ohm-cm at 25 °C, a resistivity between 10 ohm-cm and 150 ohm-cm at 100 °C, and a resistivity between 100,000 ohm-cm and 350,000 ohm-cm at 280 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 200 ohm-cm at 25 °C, a resistivity between 10 ohm-cm and 200 ohm-cm at 100 °C, and a resistivity between 100,000 ohm-cm and 375,000 ohm-cm at 280 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 300 ohm-cm at 25 °C, a resistivity between 10 ohm-cm and 300 ohm-cm at 100 °C, and a resistivity between 100,000 ohm-cm and 400,000 ohm-cm at 280 °C.In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 400 ohm-cm at 25°C, between 10 ohm-cm and 400 ohm-cm at 100°C, and between 100,000 ohm-cm and 450,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 500 ohm-cm at 25°C, between 10 ohm-cm and 500 ohm-cm at 100°C, and between 100,000 ohm-cm and 500,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 110 ohm-cm at 25°C, between 50 ohm-cm and 110 ohm-cm at 100°C, and between 150,000 ohm-cm and 325,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 150 ohm-cm at 25°C, between 50 ohm-cm and 150 ohm-cm at 100°C, and between 150,000 ohm-cm and 350,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 200 ohm-cm at 25°C, between 50 ohm-cm and 200 ohm-cm at 100°C, and between 150,000 ohm-cm and 375,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 300 ohm-cm at 25°C, between 50 ohm-cm and 300 ohm-cm at 100°C, and between 150,000 ohm-cm and 400,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 400 ohm-cm at 25°C, between 50 ohm-cm and 400 ohm-cm at 100°C, and between 150,000 ohm-cm and 450,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 500 ohm-cm at 25°C, between 50 ohm-cm and 500 ohm-cm at 100°C, and between 150,000 ohm-cm and 500,000 ohm-cm at 280°C.In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 110 ohm-cm at 25°C, between 90 ohm-cm and 110 ohm-cm at 100°C, and between 200,000 ohm-cm and 325,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 150 ohm-cm at 25°C, between 90 ohm-cm and 150 ohm-cm at 100°C, and between 200,000 ohm-cm and 350,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 200 ohm-cm at 25°C, between 90 ohm-cm and 200 ohm-cm at 100°C, and between 200,000 ohm-cm and 375,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 300 ohm-cm at 25°C, between 90 ohm-cm and 300 ohm-cm at 100°C, and between 200,000 ohm-cm and 400,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 400 ohm-cm at 25°C, between 90 ohm-cm and 400 ohm-cm at 100°C, and between 200,000 ohm-cm and 450,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 500 ohm-cm at 25°C, between 90 ohm-cm and 500 ohm-cm at 100°C, and between 200,000 ohm-cm and 500,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 110 ohm-cm at 50°C, between 10 ohm-cm and 50 ohm-cm at 150°C, and between 50,000 ohm-cm and 125,000 ohm-cm at 260°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 150 ohm-cm at 50°C, between 10 ohm-cm and 100 ohm-cm at 150°C, and between 50,000 ohm-cm and 150,000 ohm-cm at 260°C.In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 200 ohm-cm at 50 °C, between 10 ohm-cm and 150 ohm-cm at 150 °C, and between 50000 ohm-cm and 175000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 300 ohm-cm at 50 °C, between 10 ohm-cm and 200 ohm-cm at 150 °C, and between 50000 ohm-cm and 200000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 400 ohm-cm at 50 °C, between 10 ohm-cm and 250 ohm-cm at 150 °C, and between 50000 ohm-cm and 250000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 500 ohm-cm at 50 °C, between 10 ohm-cm and 300 ohm-cm at 150 °C, and between 50000 ohm-cm and 300000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 110 ohm-cm at 50 °C, between 20 ohm-cm and 50 ohm-cm at 150 °C, and between 75000 ohm-cm and 125000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 150 ohm-cm at 50 °C, between 20 ohm-cm and 100 ohm-cm at 150 °C, and between 75000 ohm-cm and 150000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 200 ohm-cm at 50 °C, between 20 ohm-cm and 150 ohm-cm at 150 °C, and between 75000 ohm-cm and 175000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 300 ohm-cm at 50 °C, between 20 ohm-cm and 200 ohm-cm at 150 °C, and between 75000 ohm-cm and 200000 ohm-cm at 260 °C.In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 400 ohm-cm at 50 °C, between 20 ohm-cm and 250 ohm-cm at 150 °C, and between 75000 ohm-cm and 250000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 500 ohm-cm at 50 °C, between 20 ohm-cm and 300 ohm-cm at 150 °C, and between 75000 ohm-cm and 300000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 110 ohm-cm at 50 °C, between 30 ohm-cm and 50 ohm-cm at 150 °C, and between 100000 ohm-cm and 125000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 150 ohm-cm at 50 °C, between 30 ohm-cm and 100 ohm-cm at 150 °C, and between 100000 ohm-cm and 150000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 200 ohm-cm at 50 °C, between 30 ohm-cm and 150 ohm-cm at 150 °C, and between 100000 ohm-cm and 175000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 300 ohm-cm at 50 °C, between 30 ohm-cm and 200 ohm-cm at 150 °C, and between 100000 ohm-cm and 200000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 400 ohm-cm at 50 °C, between 30 ohm-cm and 250 ohm-cm at 150 °C, and between 100000 ohm-cm and 250000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 500 ohm-cm at 50 °C, between 30 ohm-cm and 300 ohm-cm at 150 °C, and between 100000 ohm-cm and 300000 ohm-cm at 260 °C.In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 110 ohm-cm at 25°C, between 10 ohm-cm and 50 ohm-cm at 150°C, and between 100,000 ohm-cm and 325,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 150 ohm-cm at 25°C, between 10 ohm-cm and 100 ohm-cm at 150°C, and between 100,000 ohm-cm and 350,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 200 ohm-cm at 25°C, between 10 ohm-cm and 150 ohm-cm at 150°C, and between 100,000 ohm-cm and 375,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 300 ohm-cm at 25°C, between 10 ohm-cm and 200 ohm-cm at 150°C, and between 100,000 ohm-cm and 400,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 400 ohm-cm at 25°C, between 10 ohm-cm and 250 ohm-cm at 150°C, and between 100,000 ohm-cm and 450,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 500 ohm-cm at 25°C, between 10 ohm-cm and 300 ohm-cm at 150°C, and between 100,000 ohm-cm and 500,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 110 ohm-cm at 25°C, between 20 ohm-cm and 50 ohm-cm at 150°C, and between 150,000 ohm-cm and 325,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 150 ohm-cm at 25°C, between 20 ohm-cm and 100 ohm-cm at 150°C, and between 150,000 ohm-cm and 350,000 ohm-cm at 280°C.In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 200 ohm-cm at 25°C, between 20 ohm-cm and 150 ohm-cm at 150°C, and between 150,000 ohm-cm and 375,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 300 ohm-cm at 25°C, between 20 ohm-cm and 200 ohm-cm at 150°C, and between 150,000 ohm-cm and 400,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 400 ohm-cm at 25°C, between 20 ohm-cm and 250 ohm-cm at 150°C, and between 150,000 ohm-cm and 450,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 500 ohm-cm at 25°C, between 20 ohm-cm and 300 ohm-cm at 150°C, and between 150,000 ohm-cm and 500,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 110 ohm-cm at 25°C, between 30 ohm-cm and 50 ohm-cm at 150°C, and between 200,000 ohm-cm and 325,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 150 ohm-cm at 25°C, between 30 ohm-cm and 100 ohm-cm at 150°C, and between 200,000 ohm-cm and 350,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 200 ohm-cm at 25°C, between 30 ohm-cm and 150 ohm-cm at 150°C, and between 200,000 ohm-cm and 375,000 ohm-cm at 280°C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 300 ohm-cm at 25°C, between 30 ohm-cm and 200 ohm-cm at 150°C, and between 200,000 ohm-cm and 400,000 ohm-cm at 280°C.In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 400 ohm-cm at 25 °C, between 30 ohm-cm and 250 ohm-cm at 150 °C, and between 200,000 ohm-cm and 450,000 ohm-cm at 280 °C. In an embodiment, the PTCR heating element has a resistivity between 90 ohm-cm and 500 ohm-cm at 25 °C, between 30 ohm-cm and 300 ohm-cm at 150 °C, and between 200,000 ohm-cm and 500,000 ohm-cm at 280 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 110 ohm-cm at 50 °C, between 10 ohm-cm and 110 ohm-cm at 100 °C, and between 50,000 ohm-cm and 125,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 150 ohm-cm at 50 °C, between 10 ohm-cm and 150 ohm-cm at 100 °C, and between 50,000 ohm-cm and 150,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 200 ohm-cm at 50 °C, between 10 ohm-cm and 200 ohm-cm at 100 °C, and between 50,000 ohm-cm and 175,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 300 ohm-cm at 50 °C, between 10 ohm-cm and 300 ohm-cm at 100 °C, and between 50,000 ohm-cm and 200,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 400 ohm-cm at 50 °C, between 10 ohm-cm and 400 ohm-cm at 100 °C, and between 50,000 ohm-cm and 250,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 10 ohm-cm and 500 ohm-cm at 50 °C, between 10 ohm-cm and 500 ohm-cm at 100 °C, and between 50,000 ohm-cm and 300,000 ohm-cm at 260 °C.In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 110 ohm-cm at 50 °C, between 50 ohm-cm and 110 ohm-cm at 100 °C, and between 75000 ohm-cm and 125000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 150 ohm-cm at 50 °C, between 50 ohm-cm and 150 ohm-cm at 100 °C, and between 75000 ohm-cm and 150000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 200 ohm-cm at 50 °C, between 50 ohm-cm and 200 ohm-cm at 100 °C, and between 75000 ohm-cm and 175000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 300 ohm-cm at 50 °C, between 50 ohm-cm and 300 ohm-cm at 100 °C, and between 75000 ohm-cm and 200000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 400 ohm-cm at 50 °C, between 50 ohm-cm and 400 ohm-cm at 100 °C, and between 75000 ohm-cm and 250000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 50 ohm-cm and 500 ohm-cm at 50 °C, between 50 ohm-cm and 500 ohm-cm at 100 °C, and between 75000 ohm-cm and 300000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 110 ohm-cm at 50 °C, between 90 ohm-cm and 110 ohm-cm at 100 °C, and between 100000 ohm-cm and 125000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 150 ohm-cm at 50 °C, between 90 ohm-cm and 150 ohm-cm at 100 °C, and between 100000 ohm-cm and 150000 ohm-cm at 260 °C.In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 200 ohm-cm at 50 °C, between 90 ohm-cm and 200 ohm-cm at 100 °C, and between 100,000 ohm-cm and 175,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 300 ohm-cm at 50 °C, between 90 ohm-cm and 300 ohm-cm at 100 °C, and between 100,000 ohm-cm and 200,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 400 ohm-cm at 50 °C, between 90 ohm-cm and 400 ohm-cm at 100 °C, and between 100,000 ohm-cm and 250,000 ohm-cm at 260 °C. In an embodiment, the PTCR heating element has a resistivity between 75 ohm-cm and 500 ohm-cm at 50 °C, between 90 ohm-cm and 500 ohm-cm at 100 °C, and between 100,000 ohm-cm and 300,000 ohm-cm at 260 °C.

[0114] Figure 11 Another exemplary PTCR resistivity versus temperature curve is illustrated. In this example, the density of the PTCR material is 5700 kg / m 3 , the heat capacity is 520 J / kg K, and the thermal conductivity is 2.1 W / m K. The resistivity coefficient begins to increase initially at a temperature after about 440 K and then increases sharply between 503 K and 518 K. At 298 K, the resistivity of the PTCR material forming the PTCR heating element is 0.168 ohm-m, while at 373 K, the resistivity of the PTCR material forming the PTCR heating element is 0.105 ohm-m, and at 518 K, the resistivity of the PTCR material forming the PTCR heating element is 3.669 ohm-m. In some exemplary embodiments, the PTCR material has a density between 5000 kg / m 3 and 7000 kg / m 3 , a heat capacity between 450 J / kg K and 600 J / kg K, and a thermal conductivity between 1.5 W / m K and 3.0 W / m.

[0115] Figure 12A is a diagram illustrating an exemplary PTCR heating element 50 capable of achieving improved heating of an evaporator. The thin section of the nonlinear PTCR material 10 is shown inFigure 12A in which the nonlinear PTCR material 10 is sandwiched between conductive layers 20, which in turn are attached to conductive leads 30 such that a differential voltage can be applied to the conductive leads 30. Figure 12B is Figure 12A a cross-section of the exemplary PTCR heating element 50 shown in

[0116] In some exemplary embodiments, the PTCR heater 50 includes Figure 12A the geometry shown, having a nonlinear PTCR material thickness of 0.5 mm (height) and 5.0 mm (length and width) in the other dimensions, which is effective in an evaporator device using a combined fluid such as a combination of propylene glycol and glycerol. The electrical characteristics of the nonlinear PTCR material include these values: the T1 value is between 150 °C and 300 °C, for example between 220 °C and 280 °C; the resistivity at temperatures below T1 is between 0.01 Ohm-m and 100 Ohm-m, for example between 0.1 Ohm-m and 1 Ohm-m; the resistivity change between T1 and T2 has an increase factor of more than 10, for example more than 100; and the temperature difference between T1 and T2 is less than 200 °C, for example less than 50 °C.

[0117] Figures 13A to 13E shows the modeled temperature of the exemplary PTCR heater 50. In the example shown, the nonlinear PTCR material 10 includes a flat plate geometry with dimensions of 5 mm × 5 mm × 0.5 mm; the conductive layer 20 is formed of silver (Ag) with dimensions of 5 mm × 5 mm × 0.025 mm; and the conductive lead 30 is formed of copper (CU) with dimensions of 12 mm × 2 mm × 0.2 mm. The nonlinear PTCR material 10 includes a PTCR resistivity versus temperature curve as shown in Figure 32 with a nonlinear transition region of approximately 240 °C to approximately 300 °C. A voltage of 3 to 6 volts is applied across the conductive leads 30 of the exemplary PTCR heater 50. In these cases, the temperature of the exemplary PTCR heater 50 in open air with a free convection air flow will increase, as shown in the modeled series of Figures 13A to 13E illustrating 0.0, 0.2, 0.5, 1.0, and 2.0 seconds after the application of the differential voltage, respectively. As shown, the temperature is relatively uniform after more than 1.0 second, and the peak temperature at the surface of the conductive layer 20 is less than 270 °C.

[0118] Figures 14A to 14FShows the modeled temperature of another example of the PTCR heater 50. A gradient temperature scale is shown on the left side of each figure, where red represents the hottest temperature of approximately 255 °C and progresses through the colors of the visible spectrum (i.e., red, orange, yellow, green, blue, and purple) to the coldest temperature of approximately 23 °C. In each of the illustrated examples, the non-linear PTCR material 10 includes a flat plate geometry with dimensions of approximately 5 mm × 5 mm × 0.5 mm; the conductive layer 20 is formed of silver (Ag) with dimensions of approximately 5 mm × 5 mm × 0.025 mm; and the conductive leads 30 are formed of copper (CU) with dimensions of approximately 12 mm × 2 mm × 0.2 mm. The flat plate geometry may include two parallel sides that include the conductive layer 20 to which the conductive leads 30 are attached. The conductive leads 30 are centrally attached to the conductive layer 20 on each side of the PTCR heating element 50 through a connector 40. In an embodiment, the connector 40 is a clamp, clip, conductive paste, high temperature, lead-free solder, and / or a combination thereof.

[0119] Figure 14A Shows the temperature after 1.0 second of activation by applying current to the PTCR heating element 50. The purple conductive lead 30 remains at approximately 25 °C. The temperature of most of the PTCR material 10 and the conductive layer 20 has risen to approximately 120 °C, where the region including the connector 40 in the center is slightly cooler at a temperature of approximately 80 °C.

[0120] Figure 14B Shows the temperature after 2.0 seconds of activation by applying current to the PTCR heating element 50. The temperature of the blue / green conductive lead 30 has increased to approximately 90 °C. The temperature of most of the PTCR material 10 and the conductive layer 20 has risen to approximately 210 °C, where the region including the connector 40 in the center is cooler at a temperature of approximately 160 °C.

[0121] Figure 14C Shows the temperature after 3.0 seconds of activation by applying current to the PTCR heating element 50. The temperature of the green conductive lead 30 has increased to approximately 140 °C. The temperature of most of the PTCR material 10 and the conductive layer 20 has risen to approximately 250 °C, where the region including the connector 40 in the center is cooler at a temperature of approximately 200 °C.

[0122] Figure 14D Shows the temperature after 4.0 seconds of activation by applying current to the PTCR heating element 50. The temperature of the green conductive lead 30 has increased to approximately 160 °C. The temperature of most of the PTCR material 10 and the conductive layer 20 remains at approximately 250 °C, where the region including the connector 40 in the center is cooler at a temperature of approximately 215 °C.

[0123] Figure 14EShows the temperature after 5.0 seconds of activation by applying current to the PTCR heater 50. The temperature of the green / yellow conductive lead 30 has increased to approximately 180°C. Most of the PTCR material 10 and the conductive layer 20 remain at a temperature of approximately 250°C, where the region including the connector 40 in the center is cooler at a temperature of approximately 225°C.

[0124] Figure 14F Shows the temperature after 6.0 seconds of activation by applying current to the PTCR heating element 50. The temperature of the yellow conductive lead 30 has increased to approximately 200°C. Most of the PTCR material 10 and the conductive layer 20 remain at a temperature of approximately 250°C, where the region including the connector 40 in the center is just slightly cooler at a temperature of approximately 235°C. Figure 15 Shows the modeled temperature of an exemplary heater after 6.0 seconds of voltage application in a free convection state.

[0125] Figure 16A Shows the modeled surface temperature of an exemplary PTCR heating element as a function of time. In the model, the surface temperature of the PTCR heater starts at 25°C (i.e., room temperature) at time zero. After applying current, the surface temperature linearly rises for approximately 2 seconds to a temperature of approximately 225°C. After approximately 2 seconds, the rate of temperature increase gradually decreases, reaching a steady-state operating temperature of approximately 250°C, which is reached approximately 3 seconds after activation. In the model, it is assumed that the non-linear PTCR material is in a non-contact, free convection state and the emitted radiation is measured from a certain distance. In an embodiment, the PTCR heating element is heated to an operating temperature between 240°C and 280°C. In an embodiment, the PTCR heating element is heated to an operating temperature between 245°C and 255°C. In an embodiment, the PTCR heating element is heated to an operating temperature of approximately 250°C.

[0126] Figure 16BIllustrated is the modeled and measured maximum surface temperature as a function of time for an exemplary PTCR heater. Four measurements were repeated using an infrared camera to measure the maximum surface temperature of the PTCR heater as a function of time and then plotted it against the model of the maximum surface temperature. In the model, it is assumed that the non-linear PTCR material is in a non-contact, free convection state and the emitted radiation is measured at a certain distance. In each case, the maximum surface temperature of the PTCR heating element starts at approximately 25 °C (i.e., room temperature) at time zero. After applying the current, the maximum surface temperature linearly increases for approximately 2 seconds to reach a temperature of approximately 225 °C. After approximately 2 seconds, the rate of temperature increase gradually decreases to reach a steady-state operating temperature of approximately 250 °C, which is reached approximately 3 seconds after activation. In an embodiment, the PTCR heating element is heated to an operating temperature between 240 °C and 280 °C. In an embodiment, the PTCR heating element is heated to an operating temperature between 245 °C and 255 °C. In an embodiment, the PTCR heating element is heated to an operating temperature of approximately 250 °C.

[0127] Figure 16C Illustrated is the modeled and measured average surface temperature as a function of time for an exemplary PTCR heating element. Four measurements were repeated using an infrared camera to measure the average surface temperature of the PTCR heating element as a function of time and then plotted it against the model of the average surface temperature. In the model, it is assumed that the non-linear PTCR material is in a non-contact, free convection state and the emitted radiation is measured at a certain distance. In each case, the average surface temperature of the PTCR heating element starts at approximately 25 °C (i.e., room temperature) at time zero. After applying the current, the maximum surface temperature linearly increases for approximately 2 seconds to reach a temperature of approximately 225 °C. After approximately 2 seconds, the rate of temperature increase gradually decreases to reach a steady-state operating temperature of approximately 250 °C, which is reached approximately 3 seconds after activation. In an embodiment, the PTCR heating element is heated to an operating temperature between 240 °C and 280 °C. In an embodiment, the PTCR heating element is heated to an operating temperature between 245 °C and 255 °C. In an embodiment, the PTCR heating element is heated to an operating temperature of approximately 250 °C.

[0128] Figure 17 Illustrated is the transient current response as a function of time for an exemplary heater consistent with an embodiment of the present subject matter. In the figure, the current is measured in amperes, which increases at a nearly linear rate and reaches peak consumption approximately 1.5 seconds after activation. Thereafter, as the PTCR heater reaches its self-regulating operating temperature, the resistance rapidly increases to reduce the current consumption.

[0129] A uniform temperature can be the ideal performance of a PTCR heater, offering distinct advantages over series coil heaters, which include a series heater with a power input controlled by a temperature sensor, an electronic circuit with a microprocessor, and a complex algorithm dedicated to temperature control purposes. These existing series heaters can have a total power that is modulated in response to a temperature measurement at a point or an average temperature estimated by combining the total resistivity with the TCR (temperature coefficient of resistivity) of typical series heating elements. However, in some series heaters, the temperature within the series heater can vary by 40 °C or more due to local differences in the thermal mass of the surrounding medium and local differences in detecting medium losses, resulting in changes in the local resistivity along the series heater.

[0130] In some embodiments, the PTCR heater 50 is composed of a material having a non-linear PTCR resistivity versus temperature curve that is the same or similar to that shown, has a parallel geometry such as that shown, and has a sufficient (e.g., 3 V to 6 V) differential voltage applied to the conductive leads 30. Each given control volume within such a PTCR heater will have a temperature within a narrow range, typically less than 10 °C. This can be achieved even in the case of differential heat loads. By controlling the material and geometric arrangement of the PTCR heating element, the range of less than 10 °C can be customized for evaporation. Figure 9 shown, has a parallel geometry such as that Figures 12A to 12B shown, and has a sufficient (e.g., 3 V to 6 V) differential voltage applied to the conductive leads 30. Each given control volume within such a PTCR heater will have a temperature within a narrow range, typically less than 10 °C. This can be achieved even in the case of differential heat loads. By controlling the material and geometric arrangement of the PTCR heating element, the range of less than 10 °C can be customized for evaporation.

[0131] Alternative PTCR heater designs and geometries are possible.

[0132] In an embodiment, the PTCR heater can include a heat exchanger for preheating the air entering and passing through the evaporable material. Figure 18 is a perspective view of an exemplary PTCR heater assembly 395, which includes a PTCR heater 390 and a heat exchanger element 320 that enables convective heating of the evaporable material and improved uniform heating.

[0133] Exemplary PTCR heater assembly 395 (also referred to as a rectangular PTCR air heater assembly) includes a PTCR heater 390 that includes a PTCR material 300 sandwiched between conductive layers 305. In contact with the conductive layers 305 is a heat exchanger element 320, which can be made of, for example, aluminum or other thermally conductive materials. The heat exchanger element 320 can be made by extrusion of a thermally conductive material or assembled. In an embodiment, the heat exchanger element 320 can be a metal foam, such as an aluminum foam. The heat exchanger element 320 can be made by extrusion, machining, milling, casting, foaming, printing, injection molding, forging, stamping, sintering, and other metal forming methods. Surrounding the heat exchanger element 320 is a heater assembly cover 350. In an embodiment, the heater assembly cover 350 includes a non-conductive material. In an embodiment, the heater assembly cover 350 includes a non-thermally conductive material. In an embodiment, the heater assembly cover 350 includes a metal with a non-conductive coating that isolates the heater assembly cover 350 from the heat exchanger element 320. In an embodiment, the heater assembly cover 350 contains polytetrafluoroethylene (PTFE).

[0134] Figure 19 is an exploded view of a PTCR evaporation assembly 398, including an exploded view of an exemplary PTCR heater assembly 395. In some embodiments, the PTCR evaporation assembly 398 is rectangular. The PTCR evaporation assembly 398 includes an exemplary PTCR heater assembly 395 and a product cover 380 for housing a disposable product 360. In some embodiments, both the product cover 380 and the disposable product 360 are rectangular. In an embodiment, the disposable product 360 within the product cover 380 can include a disposable product containing a solid evaporable material. In an embodiment, the product cover 380 is a disposable liquid cartridge (e.g., pod) configured to house a liquid evaporable material. In an embodiment, the product cover 380 is a disposable liquid cartridge (e.g., pod) that includes a first air inlet and / or a wick and is configured to house a liquid evaporable material.

[0135] Figure 20 is a perspective view of an assembled exemplary PTCR evaporation assembly 398. The product cover 380 containing the disposable product can be attached to the heater assembly cover 350, the PTCR heater assembly, and / or an adjacent portion on the opposite side of the product cover 380 by an interference fit, press fit, snap fit coupling, magnetic coupling, adhesive, and other fastening means. The product cover 380 can be releasably attached such that it can be separated from the evaporator device to replace the disposable product and then reassembled.

[0136] Figure 21Is a perspective view of an exemplary PTCR evaporation assembly 398 and a disposable product 360. In an embodiment, the disposable product 360 and the product lid 380 may include a disposable product containing a solid evaporable material. In an embodiment, the disposable product 360 and the product lid 380 may include a disposable liquid cartridge (e.g., pod) that houses a liquid evaporable material. In an embodiment, the disposable product 360 and the product lid 380 may include a disposable liquid cartridge (e.g., pod) having a first air inlet and / or a wick, and containing a liquid evaporable material. Although Figure 21 the PTCR heater is not shown in, the PTCR heater is inserted into the volume portion 304 between the heat exchanger elements 320. Compared to having only a PTCR heater (without a heat exchanger) to heat the incoming air, the heat exchanger elements 320 provide an increased surface area for heating more incoming air. Surrounding the heat exchanger elements 320 is a heater assembly lid 350. In an embodiment, the flow rate of the incoming air through the PTCR heater assembly 395 is approximately 1.4 liters per minute. The heat exchanger elements 320 can reach a steady-state temperature of over 200 °C to quickly heat the incoming air. The heat exchanger elements 320 can be designed to maximize the specific surface area (mm 2 / mm 3 ), which provides improved heat transfer from the PTCR heater to the heat exchanger elements 320 and also provides improved heat transfer from the heat exchanger elements 320 to the incoming air. As Figure 21 shown, the heat exchanger elements 320 can be a fin design made of a thermally conductive material (e.g., metal, such as aluminum, copper, steel, stainless steel, titanium).

[0137] Figure 22 Is a perspective view of an exemplary PTCR evaporation assembly 398 and a disposable product 360 after the PTCR heater 390 has been activated for approximately 0.2 seconds. The PTCR heater 390 heats the heat exchanger elements 320, which transfer heat to the air entering the PTCR heater assembly 395. The air leaving the PTCR heater assembly 395 has been heated to a temperature between approximately 110 °C and approximately 160 °C. The heated air stream flows through the disposable product 360 (e.g., a tobacco-containing medium) at a flow rate of approximately 1.4 liters per minute. The vapor and / or aerosol leaving the PTCR evaporation assembly 398 contains evaporable material released from the disposable product 360 at a temperature between approximately 50 °C and approximately 150 °C.

[0138] Figure 23Is a perspective view of an exemplary PTCR evaporation assembly 398 and a disposable product 360 after the PTCR heater 390 has been activated for approximately 0.5 seconds. The PTCR heater 390 heats the heat exchanger element 320, which transfers heat to the air entering the PTCR heater assembly 395. The air leaving the PTCR heater assembly 395 has been heated to a temperature between approximately 150°C and approximately 210°C. The heated air stream flows through the disposable product 360 (such as a tobacco-containing medium) at a flow rate of approximately 1.4 liters per minute. The vapor and / or aerosol leaving the PTCR evaporation assembly 398 contains evaporation materials released from the disposable product 360 at a temperature between approximately 100°C and approximately 210°C.

[0139] Figure 24 Is a perspective view of an exemplary PTCR evaporation assembly 398 and a disposable product 360 after the PTCR heater 390 has been activated for approximately 1.0 second. The PTCR heater 390 heats the heat exchanger element 320, which transfers heat to the air entering the PTCR heater assembly 395. The air leaving the PTCR heater assembly 395 has been heated to a temperature between approximately 170°C and approximately 230°C. The heated air stream flows through the disposable product 360 (such as a tobacco-containing medium) at a flow rate of approximately 1.4 liters per minute. The vapor and / or aerosol leaving the PTCR evaporation assembly 398 contains evaporation materials released from the disposable product 360 at a temperature between approximately 110°C and approximately 220°C.

[0140] Figure 25 Is a perspective view of an exemplary PTCR evaporation assembly 398 and a disposable product 360 after the PTCR heater 390 has been activated for approximately 2.0 seconds. The PTCR heater 390 heats the heat exchanger element 320, which transfers heat to the air entering the PTCR heater assembly 395. The air leaving the PTCR heater assembly 395 has been heated to a temperature between approximately 180°C and approximately 240°C. The heated air stream flows through the disposable product 360 (such as a tobacco-containing medium) at a flow rate of approximately 1.4 liters per minute. The vapor and / or aerosol leaving the PTCR evaporation assembly 398 contains evaporation materials released from the disposable product 360 at a temperature between approximately 120°C and approximately 230°C.

[0141] Figure 26FIG. 0 is a perspective view of an exemplary PTCR vaporization assembly 398 and a disposable product 360 after the PTCR heater 390 has been activated for approximately 3.0 seconds. The PTCR heater 390 heats the heat exchanger element 320, which transfers heat to the air entering the PTCR heater assembly 395. The air exiting the PTCR heater assembly 395 has been heated to a temperature between approximately 180° C. and approximately 240° C. The heated air stream flows through the disposable product 360 (e.g., a tobacco-containing medium) at a flow rate of approximately 1.4 liters per minute. The vapor and / or aerosol exiting the PTCR vaporization assembly 398 contains vaporized material released from the disposable product 360 at a temperature between approximately 120° C. and approximately 230° C.

[0142] The present subject matter is not limited to rectangular geometries. In an embodiment, the PTCR heater is a polygon that is not rectangular. For example, alternative designs of the PTCR heater may differ from planar geometries in many configurations produced by extrusion or injection molding. For example, Figure 27 FIG. 5 is a perspective view of an exemplary PTCR heater 290 having a cylindrical geometry. In this example, the PTCR heater 290 includes a PTCR material 200 having a surface conductive layer 205, each surface conductive layer being cylindrical.

[0143] Figure 28 FIG. 9 is an exploded view showing an exemplary PTCR heater assembly 295, which includes an exemplary PTCR heater 290, an external heat exchanger 210, an internal heat exchanger 220, a diverter 230, and a heater assembly cover 250, each of the above components being cylindrical. Figure 29 FIG. 11 is a perspective view of the exemplary PTCR heater assembly 295. Figure 30 FIG. 13 is a perspective view of an exemplary PTCR vaporization assembly 298 with the outer cover and the diverter 230 removed, showing the orientation in which the PTCR heater 290, the external heat exchanger 210, and the internal heat exchanger 220 are aligned with the disposable product 260.

[0144] Figure 31 FIG. 17 is a perspective view of an exemplary PTCR vaporization assembly 298, which includes a PTCR heater 290, an external heat exchanger 210, an internal heat exchanger 220, a diverter 230, a heater assembly cover 250, and a product cover 280 (in Figure 18 which the product cover obscures the disposable product 260).

[0145] Figure 32 FIG. 23 is a graph of the logarithm of the resistivity of an exemplary vaporization device having a PTCR heater as a function of temperature. Figure 32The performance shown is calculated from an example representing the performance of an exemplary embodiment of a cylindrical PTCR evaporation assembly 298. The exemplary PTCR evaporation assembly 298 is an HNB device where a solid evaporable material (e.g., HNB product) is a disposable product 260, which is treated as a porous medium in the calculation, and the mass specific surface area Density Convective heat transfer coefficient The volume specific surface area can be calculated as S vol = S m x ρ = 10000 cm 2 / g × 1000 g / kg × m 2 / 10000 cm 2 , and From which the volume heat transfer coefficient is derived

[0146] For the above calculations, the environmental conditions are at a standard pressure of 1 atmosphere and a temperature of 20.05 °C. The input air flow rate is constant at 1.4 l / m, and the voltage applied across the opposing conductive layers 205 is constant at 3.7 volts. Beyond the Figure 32 shown PTCR behavior, no current limit is applied.

[0147] The calculated evaporation device with a PTCR heater includes a conductive layer 205 made of silver, a cylindrical external heat exchanger 210 and a cylindrical internal heat exchanger 220 (which is an aluminum extrusion), a diverter 230 and a heater assembly cover 250 made of PTFE, and a product cover 280 made of paper.

[0148] Figure 33 is a cross-sectional view showing the temperature simulation of an exemplary embodiment of the PTCR evaporation assembly 298, which PTCR evaporation assembly 298 is also described above in connection with Figure 32 . The PTCR evaporation assembly 298 includes a PTCR heater assembly 295 for heating a disposable product (e.g., a solid evaporable material) 260. Figures 34A to 34G is a cutaway view showing the transient response of temperature as colors for an exemplary embodiment of the PTCR evaporation assembly 298 with a PTCR heater assembly 295. Figures 34A to 34G Shows that the temperature anywhere does not exceed 280 °C, well below the combustion temperature of the disposable product 260. It can also be seen in Figures 34A to 34G that the heating of the disposable product (e.g., a solid evaporable material) 260 proceeds in a wave form from upstream to downstream, thus eliminating cross-sectional hotspots and the resulting voids with different porosities.

[0149] Figure 35A perspective view and an end view of a mouthpiece 335 having a vapor inlet 341, an aerosol outlet 342, and a plurality of air inlets are shown. The plurality of air inlets includes a first plurality of air inlets 340a and a second plurality of air inlets 340b. The first plurality of air inlets 340a includes 14 holes (each hole being an air inlet), and the second plurality of air inlets 340b includes an additional 14 holes (each hole being an air inlet). In some embodiments, the first plurality of air inlets 340a includes a number of holes between 4 and 24, and the second plurality of air inlets 340b includes a number of holes between 4 and 24. Each hole of the plurality of air inlets may be circular and have a diameter of about 0.4 mm. In some embodiments, each hole of the plurality of air inlets may be circular and have a diameter between about 0.2 mm and about 0.6 mm. Each hole of the plurality of air inlets may be arranged in a plane. Each hole may be formed through a certain thickness of the mouthpiece 335 at an angle α of about 30 degrees with respect to the outer surface of the mouthpiece 335. In some embodiments, each hole may be formed through a certain thickness of the mouthpiece 335 at an angle α between about 15 degrees and about 45 degrees with respect to the outer surface of the mouthpiece 335. Each hole of the first plurality of air inlets 340a may have an angle α that is internally oriented in the same direction with respect to the angle of an adjacent hole. Each hole of the second plurality of air inlets 340b may have an angle α that is internally oriented in the same direction with respect to the angle of an adjacent hole. The mouthpiece 335 may be tapered from the vapor inlet 341 to the aerosol outlet 342. The cross-sectional area of the vapor inlet 341 may be at least four times as large as the cross-sectional area of the aerosol outlet 342. In some embodiments, the cross-sectional area of the vapor inlet 341 may be about 1.5 times to 6 times the cross-sectional area of the aerosol outlet 342.

[0150] Figure 36 is a perspective view of the mouthpiece 335 attached to the PTCR rectangular evaporation assembly 395. The vapor inlet of the mouthpiece 335 may be attached to the PTCR rectangular evaporation assembly 395 by interference fit, press fit, snap fit coupling, magnetic coupling, adhesives, and other fastening means. The mouthpiece 335 may be releasably attached to the product cap 380 such that the two pieces may be separated to replace the evaporable product and then reconnected together. In other embodiments, the product cap 380 may be removed from the evaporator assembly 390 to replace the evaporable product contained therein and then reconnected together. In this embodiment, the first plurality of air inlets 340a may include eight holes, and the second plurality of air inlets 340b may include an additional eight holes. The tapered body of the mouthpiece 335 provides a comfortable and adjustable fit for the user inhaling the aerosol exiting through the aerosol outlet 342.

[0151] Figure 37is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns, without any benefit from the air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b. The air flow is substantially laminar and is not well mixed through the PTCR rectangular evaporation assembly 395 and the attached nozzle 335. The incoming air across the heat exchanger element 320 is rapidly heated to above 200 °C before passing through the disposable rectangular product. As Figure 37 shown, the aerosol exits from the aerosol outlet 342 of the nozzle 335 and has been cooled to an average temperature between 100 °C and 160 °C. The difference between the vapor inlet temperature and the aerosol outlet temperature is less than 100 °C.

[0152] Figure 38 is a transparent end view observed through the aerosol outlet of the nozzle 335 including a plurality of air inlets, which shows the air flow field pattern. The plurality of air inlets includes a first plurality of air inlets 340a and a second plurality of air inlets 340b. As Figure 38 shown, the first plurality of air inlets 340a includes eight holes (each hole being an air inlet), and the second plurality of air inlets 340b includes another eight holes (each hole being an air inlet). As discussed above with respect to Figure 35 , each hole can be formed to pass through a certain thickness of the nozzle 335 at an angle α between approximately 15 degrees and 45 degrees with respect to the outer surface of the nozzle 335. Each hole of the first plurality of air inlets 340a can each have an internal angle with respect to adjacent holes that is open in the same direction. Each hole of the second plurality of air inlets 340b can each have an internal angle with respect to adjacent holes that is open in the same direction.

[0153] Each hole of the plurality of air inlets is arranged in a plane. The plane formed by the holes of the first plurality of air inlets 340a and the second plurality of air inlets 340b passes through a cross-section of the nozzle 335, and this cross-section is in the shape of two overlapping circles. Due to the circular arrangement of the holes and the inner parts of the angle α opening in the same relative direction, the air passing through the holes flows in a circular motion to form a vortex. The first plurality of air streams passing through the first plurality of air inlets 340a form a first vortex, and the second plurality of air streams passing through the second plurality of air inlets 340b form a second vortex. The first vortex has a first rotation axis and a first rotation direction around the first rotation axis. The first rotation direction is the direction determined by the inner part of the angle α for each hole of the first plurality of air inlets 340a. The second vortex has a second rotation axis and a second rotation direction around the second rotation axis. The second rotation direction is the direction determined by the inner part of the angle α for each hole of the second plurality of air inlets 340b. The first rotation direction and the second rotation direction can be opposite directions. For example, the first rotation direction is counterclockwise and the second rotation direction is clockwise. In other embodiments, the first rotation direction is clockwise and the second rotation direction is counterclockwise. In other embodiments, the first rotation direction is clockwise and the second rotation direction is clockwise, or the first rotation direction is counterclockwise and the second rotation direction is counterclockwise. Due to the narrowing of the nozzle 335, the first rotation axis and the second rotation axis are not parallel. The first rotation axis and the second rotation axis intersect at a point outside the evaporator device and passing through the aerosol outlet.

[0154] The vortices generated in the nozzle 335 contribute to mixing the air entering through the plurality of air inlets to cool the aerosol leaving through the aerosol outlet. By generating counter-rotating vortices (i.e., the first vortex rotating counterclockwise and the second vortex rotating clockwise, or vice versa), the first plurality of air streams collide with the second plurality of air streams to generate turbulence, so as to further improve the mixing of the inlet air and the vapor / aerosol inside the nozzle. Due to the conservation of angular momentum, the narrowing of the nozzle 335 from the vapor inlet to the aerosol outlet makes the vortices rotate faster, which creates additional turbulence and improves the mixing. The turbulence of the mixing inside the nozzle 335 creates a more uniform temperature profile of the aerosol leaving through the aerosol outlet without generating excessive pressure drop. This provides an improved experience for the user, enabling the user to inhale the aerosol at a comfortable temperature without excessive sucking effort. The turbulence of the mixing inside the nozzle 335 also produces smaller aerosol droplets, which are suitable for delivering the aerosol to the deep lung tissue of the user and avoiding the deposition of the aerosol in the user's mouth or throat.

[0155] Although the present design is described with the air inlet configuration of the nozzle generating two vortices, it is contemplated to generate more than two vortices within the nozzle. While a single vortex can provide some mixing of the inlet air and the aerosol within the nozzle, a portion of the heated aerosol may flow along the axis of the single vortex and exit the aerosol outlet without sufficient cooling.

[0156] Figure 39 is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns 0.1 seconds after activation of the PTCR heater. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 70°C and approximately 90°C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20°C and approximately 25°C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 20°C and approximately 50°C.

[0157] Figure 40 is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns 0.2 seconds after activation of the PTCR heater. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 110°C and approximately 160°C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20°C and approximately 25°C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 25°C and approximately 60°C.

[0158] Figure 41 is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns 0.3 seconds after activation of the PTCR heater. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 140°C and approximately 180°C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20°C and approximately 25°C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 40°C and approximately 80°C.

[0159] Figure 42is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns 0.4 seconds after the activation of the PTCR heater. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 150 °C and approximately 200 °C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20 °C and approximately 25 °C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 50 °C and approximately 90 °C.

[0160] Figure 43 is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns 0.5 seconds after the activation of the PTCR heater. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 160 °C and approximately 210 °C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20 °C and approximately 25 °C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 50 °C and approximately 90 °C.

[0161] Figure 44 is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns 1.0 second after the activation of the PTCR heater. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 160 °C and approximately 210 °C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20 °C and approximately 25 °C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 55 °C and approximately 100 °C. The difference between the vapor inlet temperature and the aerosol outlet temperature is at least 100 °C.

[0162] Figure 45 is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field patterns 2.0 seconds after the activation of the PTCR heater. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 170 °C and approximately 220 °C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20 °C and approximately 25 °C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 60 °C and approximately 100 °C. The difference between the vapor inlet temperature and the aerosol outlet temperature is at least 100 °C.

[0163] Figure 46 is a perspective view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 395, showing the air flow and temperature field pattern after 3.0 seconds of PTCR heater activation. The air leaving the PTCR rectangular evaporation assembly 395 has been heated to a temperature between approximately 190°C and approximately 240°C. The air entering the first plurality of air inlets 340a and the second plurality of air inlets 340b is at room temperature (between approximately 20°C and approximately 25°C) and is mixed with the vapor entering the vapor inlet of the nozzle 335. The aerosol leaving the aerosol outlet 342 of the nozzle 335 has been cooled to a temperature between approximately 60°C and approximately 100°C. The difference between the vapor inlet temperature and the aerosol outlet temperature is at least 100°C.

[0164] Figure 47 Illustrates the air temperature leaving the nozzle as a function of time for an exemplary evaporator device with a PTCR heater. The air temperature leaving the nozzle rises sharply at a rate of approximately 6,000°C / minute between 0 and 0.4 seconds. Between 0.4 seconds and 0.6 seconds, the rate of temperature change for the air temperature leaving the nozzle decreases significantly until it reaches a steady-state rate of approximately 188°C / minute from 0.6 seconds to 3.0 seconds.

[0165] Figure 48 Illustrates the current response as a function of time for an exemplary evaporator device with a PTCR heater. At activation, the current of the PTCR heater is approximately 43 amperes until approximately 0.2 seconds after activation. Between 0.2 seconds and 0.3 seconds after activation, the current surges to a peak of approximately 47 amperes and then decreases to a steady-state current of approximately 2 amperes at approximately 2 seconds after activation.

[0166] Figure 49 Shows a top view of the nozzle 335 attached to the PTCR rectangular evaporation assembly 398 with the product cover and lid removed. Figure 49 The heat exchanger element and the conductive coating are also removed to show the exposed PTCR material 300. The PTCR material 300 is color-coded to represent the current density two seconds after the start of the following transient simulation, with air leaving the aerosol outlet 342 of the nozzle 335 at a flow rate of 1.4 liters per minute and a voltage difference of 3.7 volts applied across the PTCR material 300 arranged between the conductive coatings. The ambient incoming air flow on the side opposite the aerosol outlet 342 causes a greater heat load near the ambient air inlet side (upstream side) compared to the opposite side (downstream side). As Figure 49 shown, the differential heat load results in a differential current density within the PTCR material 300. A current density legend is also shown and ranges from 50,000 amperes per square meter to 100,000 amperes per square meter.Figure 49 is consistent with Figure 1 the principle of the PTCR material presented in

[0167] Any one of the above-mentioned nozzles can be attached to any one of the above-mentioned PTCR evaporation assemblies. For example, any one of the above-mentioned nozzles can be detachably attached to any one of the above-mentioned PTCR evaporation assemblies by interference fit, press fit, snap fit coupling, magnetic coupling, adhesives, and other fastening means. In an embodiment, the nozzle is separated from the PTCR evaporation assembly to replace the evaporable material contained therein, and then re-coupled together.

[0168] In the above specification and claims, phrases such as "at least one" or "one or more" may appear after a conjunctive listing of elements or features. The term "and / or" may also appear in a listing of two or more elements or features. Unless there is an implicit or explicit contradiction with the context in which it is used, the phrase is intended to mean any of the listed elements or features individually, or any combination of any of the listed elements or features with any of the other listed elements or features. For example, the phrases "at least one of A and B", "one or more of A and B", and "A and / or B" each are intended to mean "A alone, B alone, or A and B together". A similar interpretation applies to listings of three or more items. For example, the phrases "at least one of A, B, and C", "one or more of A, B, and C", "A, B, and / or C" each are intended to mean "A alone, B alone, C alone, A and B together, A and C together, B and C together, or A and B and C together". Additionally, the term "based on" as used above and in the claims is intended to mean "at least partially based on", such that unrecited features or elements are also permissible.

[0169] The subject matter described herein can be embodied specifically in a system, apparatus, method, and / or article, depending on the desired configuration. The embodiments listed in the above description do not represent all embodiments consistent with the subject matter described herein. Instead, they are merely examples consistent with relevant aspects of the subject matter. Although some variations have been described in detail above, other modifications or additions can be made. In particular, further features and / or variations can be provided in addition to the features and / or variations listed herein. For example, the embodiments described above can be directed to various combinations and sub-combinations of the disclosed features and / or combinations and sub-combinations of several further features disclosed above. Additionally, the logical flows described in the figures and / or the logical flows described herein do not necessarily require the specific order or sequential order shown to achieve the desired result. Other embodiments are within the scope of the following claims.

Claims

1. An evaporator device, comprising: A housing including an air inlet; A heating element within the housing, the heating element including a non-linear positive temperature coefficient of resistivity material; A heat exchanger thermally coupled to the heating element and arranged to receive an air flow from the air inlet, the heat exchanger configured to transfer heat between the heating element and the air flow to produce a heated air flow, wherein the heated air flow exiting the heat exchanger is configured to evaporate an evaporable material; A cartridge having a first air inlet, wherein the cartridge includes: A reservoir containing the evaporable material; A wick in fluid communication with the evaporable material, the wick arranged to receive the heated air flow from the heat exchanger to evaporate the evaporable material to produce a vapor and / or a first aerosol; And A mouthpiece configured to receive the vapor and / or the first aerosol through a vapor inlet.

2. The evaporator device according to claim 1, further comprising: A solid evaporable material arranged to receive the vapor and / or the first aerosol to produce a second aerosol, Wherein the mouthpiece is configured to receive the second aerosol after the vapor and / or the first aerosol passes through the solid evaporable material.

3. The evaporator device according to claim 1 or 2, wherein the cartridge is configured to receive the heated air flow through the first air inlet and direct the heated air flow across the wick.

4. The evaporator device according to claim 1 or 2, wherein the wick is located in the path of the heated air flow between the heating element and the mouthpiece.

5. The evaporator device according to claim 1 or 2, wherein the cartridge includes a second air inlet configured to draw a second air flow into the cartridge for mixing with the heated air flow.

6. The evaporator device according to claim 5, wherein the second air inlet is located within the mouthpiece.

7. The evaporator device according to claim 1 or 2, wherein the non-linear positive resistivity temperature coefficient material includes a resistivity transition region in which the resistivity increases within a certain temperature range such that when the heating element is heated to a first temperature above the resistivity transition region, the current from the power source is reduced to a level that limits further temperature rise of the heating element.

8. The evaporator device according to claim 7, wherein the resistivity transition region starts at the first temperature between 150 °C and 350 °C.

9. The evaporator device according to claim 8, wherein the resistivity transition region starts at the first temperature between 220 °C and 300 °C.

10. The evaporator device according to claim 9, wherein the resistivity transition region starts at the first temperature between 240 °C and 280 °C.

11. The evaporator device according to claim 7, wherein the increase in resistivity within the temperature range of the resistivity transition region includes an increase factor of at least 10, the increase factor characterizing the relative resistivity change between the resistivity at a first temperature associated with the start of the resistivity transition region and the resistivity at a second temperature associated with the end of the resistivity transition region.

12. The evaporator device according to claim 7, wherein the resistivity transition region starts at the first temperature, and the resistivity of the heating element at a temperature below the first temperature is between 0.2 ohm-cm and 200 ohm-cm.

13. The evaporator device according to claim 1 or 2, further comprising: A power source configured to provide a voltage between 3 volts and 50 volts to the heating element; A pressure sensor; And A controller coupled to the pressure sensor and configured to detect an inhalation and, in response, electrically connect the power source to the heating element.

14. The evaporator device according to claim 1, wherein the nozzle comprises: A vapor inlet and an aerosol outlet; A first plurality of air inlets disposed between the vapor inlet and the aerosol outlet and configured to provide a first plurality of air flows that form a first vortex having a first axis of rotation and a first direction of rotation about the first axis of rotation; And A second plurality of air inlets disposed between the vapor inlet and the aerosol outlet and configured to provide a second plurality of air flows that form a second vortex having a second axis of rotation and a second direction of rotation about the second axis of rotation, Wherein the first plurality of air flows and the second plurality of air flows are configured to mix with the vapor entering through the vapor inlet and form an aerosol that exits through the aerosol outlet.

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