Method for operating an electronic vapour inhaler

Abstract

The present invention relates to an electronic vapour inhaler, and in particular to a method of operating an electronic vapour inhaler in which a non-liquid flavour-release medium is heated to produce a vapour for inhalation by a user.SOLUTION: A method of operating an electronic vapour inhaler 10 comprising an induction heating device 34, the induction heating device 34 comprising an induction coil 36 for generating an alternating electromagnetic field to heat an induction heatable element 28 and thereby heat a non-liquid flavour-release medium 30, the method comprising intermittently energising the induction coil 36 to generate an intermittent alternating electromagnetic field which provides pulsed heating and cooling of the induction heatable element 28.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to electronic vapor inhalers, and more particularly to a method of operating an electronic vapor inhaler in which a non-liquid flavor-releasing medium is heated to produce a vapor for inhalation by a user. [Background technology]

[0002] The use of electronic vapor inhalers (also known as e-cigarettes, e-cigarettes, and personal vaporizers), which can be used as an alternative to traditional smoking articles such as lit-end cigarettes, cigars, and pipes, is becoming increasingly common and widespread. The most widely used electronic vapor inhalers are typically battery-powered and use a resistive heating element to heat and atomize a nicotine-containing liquid to produce a nicotine-containing vapor that can be inhaled by the user. The vapor is inhaled through a mouthpiece to deliver the nicotine to the lungs, and the vapor exhaled by the user generally mimics the appearance of smoke from a traditional smoking article. Inhaling the vapor produces a physical sensation similar to that of a traditional smoking article, but because no combustion is involved, harmful chemicals such as carbon dioxide and tar are not produced or inhaled.

[0003] In the aforementioned conventional electronic cigarettes, the liquid is drawn up to a resistive heating element. This provides rapid atomization of the liquid, allowing the electronic cigarette to start quickly when activated by a user, but the flavor may not be optimal. Conventional tobacco material or other non-liquid flavor-releasing medium may be used in place of the liquid to provide enhanced flavor characteristics. However, the start-up time (i.e., "time to first puff") after a user first activates the electronic cigarette is longer because it takes longer for the tobacco material or other non-liquid flavor-releasing medium to heat to a temperature that produces a sufficient amount of vapor. This is due to the higher thermal mass and slower response of the resistive heating element.

[0004] Patent Document 1 proposes a solution to this problem by providing a resistively heated aerosol generating device with three heating stages. Specifically, there is a first stage in which the temperature of the heating element is raised from ambient temperature to a first temperature, a second stage in which the temperature of the heating element is lowered below the first temperature, and a third stage in which the temperature of the heating element is raised again. The first stage is a high-temperature stage in which the temperature of the heating element is raised as close as possible to the combustion temperature of the aerosol-forming substrate used in the device. The second stage is a low-temperature stage in which the temperature of the heating element is lowered to provide sustained delivery of aerosol to the user. The third stage is also a high-temperature stage and is intended to provide sustained delivery of aerosol to the user as the aerosol-forming substrate is depleted.

[0005] Patent Document 1 lists a preferred temperature range for the first stage as 340°C to 400°C, with specific examples of 360°C for 45 seconds, 340°C for 60 seconds, and 380°C for 30 seconds. Patent Document 1 states that the maximum operating temperature for each of the first, second, and third stages is preferably no higher than approximately 380°C, which is the combustion temperature of undesirable compounds present in conventional, end-lit cigarettes. Therefore, it is clear that the temperature of the heating element during the first stage is very high and close to the maximum allowable temperature for a relatively long period of time. This can be extremely unpleasant, potentially causing scorching of the aerosol-forming substrate and producing an aerosol with an unpleasant or off-tasting flavor. This can also initiate the generation of undesirable compounds that occur in conventional, end-lit cigarettes as a result of combustion. Furthermore, even at the very high temperatures described in Patent Document 1, the start-up time is still unacceptably long, especially compared to the instantaneous availability of end-lit cigarettes or electronic cigarettes that heat and atomize liquids.

[0006] Therefore, there is a need for an electronic vapor inhaler that overcomes these obstacles. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2014 / 102091 Summary of the Invention

[0008] According to a first aspect of the present disclosure, there is provided a method of operating an electronic vapor inhaler comprising an induction heating device, the induction heating device comprising an induction coil for generating an alternating electromagnetic field to heat an inductively heatable element and thereby heat a non-liquid flavor-releasing medium, the method comprising intermittently exciting the induction coil to generate an intermittent alternating electromagnetic field that provides pulsed heating and cooling of the inductively heatable element.

[0009] According to a second aspect of the present disclosure, an induction heating device comprising an induction coil for generating an alternating electromagnetic field to heat an inductively heatable element and thereby heat the non-liquid flavor-releasing medium; a controller for controlling operation of the induction heating apparatus to intermittently energize the induction coil to generate an intermittent alternating electromagnetic field that provides pulsed heating and cooling of the induction heatable element; An electronic vapor inhaler comprising:

[0010] The non-liquid flavor-releasing medium may include any material or combination of materials that can be heated to release a vapor for inhalation by a user. The non-liquid flavor-releasing medium is a dry material and can be easily handled. The non-liquid flavor-releasing medium may be tobacco or a tobacco material, or a dry herbal material. The non-liquid flavor-releasing medium may be in any suitable shape, including fine pieces or pellets, or a fibrous shape. The non-liquid flavor-releasing medium may be impregnated with a vapor-forming medium, such as propylene glycol, glycerol, or a combination of both.

[0011] The inductively heatable element has a low thermal mass, allowing it to heat rapidly in the presence of an alternating electromagnetic field generated by the induction coil of an induction heating device. For example, the inductively heatable element can heat from ambient temperature to approximately 250°C in 0.2 seconds. The low thermal mass also allows the inductively heatable element to cool rapidly in the absence of an alternating electromagnetic field, as thermal energy is transferred to the surrounding non-liquid flavor-releasing medium. By intermittently energizing the induction coil to provide an intermittent alternating electromagnetic field and intermittent or pulsed heating and cooling of the inductively heatable element, a large amount of energy can be delivered to the inductively heatable element without burning or overheating the non-liquid flavor-releasing medium. Heat transfer from the inductively heatable element to the non-liquid flavor-releasing medium, for example by conduction, radiation, or convection, can result in the non-liquid flavor-releasing medium, or one or more localized regions thereof, being rapidly heated to a temperature within the operating temperature range that generates vapor having suitable (including flavor and aroma) characteristics for inhalation by a user. The intermittent or pulsed heating and cooling of the inductively heatable element, combined with the low thermal mass of the inductively heatable element, ensures that the non-liquid flavor-releasing medium does not reach temperatures higher than the operating temperature range where overheating, burning, or scorching would occur, and allows the non-liquid flavor-releasing medium to be rapidly heated to temperatures within the operating temperature range.

[0012] The method may include varying a pulse frequency of power supplied to the induction coil to intermittently energize the induction coil. The method may include varying a pulse amplitude of power supplied to the induction coil to intermittently energize the induction coil. The method may include varying a duty cycle of power supplied to the induction coil to intermittently energize the induction coil. The pulse frequency and / or pulse amplitude and / or or duty cycle, provides controlled pulsed heating and cooling of the inductively heatable element, thereby allowing the operating temperature of the non-liquid flavour releasing medium to be controlled.

[0013] By pulsating heating and cooling of the inductively heatable element, the non-liquid flavor-releasing medium may be heated to an operating temperature within an operating temperature range having a lower limit of 150°C to 200°C and an upper limit of 200°C to 250°C. Typically, the operating temperature range is 180°C to 240°C. When the non-liquid flavor-releasing medium is tobacco material, which may typically have a combustion temperature in the range of 380°C, it is clear that the upper limit of the operating temperature range is substantially lower than the combustion temperature. As a result, scorching or burning of the tobacco material is avoided, ensuring that the vapor generated by heating the tobacco material has optimal properties.

[0014] The method may include a first operating stage in which the induction coil is intermittently energized to generate an intermittent alternating electromagnetic field that provides pulsed heating and cooling of the inductively heatable element to heat the non-liquid flavor-releasing medium to a temperature within the operating temperature range. The first operating stage may typically have a duration not exceeding 10 seconds. More typically, the duration is not exceeding 5 seconds. It is therefore clear that the start-up time (i.e., "time to first puff") is significantly shorter than the start-up time of the aerosol generating device described in U.S. Patent No. 5,649,499.

[0015] The method may include a second operating phase in which the induction coil is intermittently energized to generate an intermittent alternating electromagnetic field that provides pulsed heating and cooling of the inductively heatable element to maintain the average temperature of the non-liquid flavor-releasing medium within an operating temperature range. The intensity of the alternating electromagnetic field is typically lower during the second operating phase than during the first operating phase. This is possible because the components of the electronic vapor inhaler have already been heated during the first operating phase and because the amount of moisture and vapor-forming medium in the non-liquid flavor-releasing medium is reduced. Therefore, less energy is required to maintain the average temperature of the non-liquid flavor-releasing medium within the operating temperature range.

[0016] During the second operating phase, the induction coil may be intermittently energized based on user demand. Such implementation is also possible due to the low thermal mass and rapid heating and cooling characteristics of the inductively heatable element, which allows it to heat rapidly in the presence of an electromagnetic field and cool rapidly in the absence of an electromagnetic field. User demand may be detected by any suitable means indicating that a user's inhalation of the electronic vapor inhaler is occurring or is imminent. For example, the electronic vapor inhaler may include an accelerometer that detects the user's movement of the electronic vapor inhaler toward the lips, a capacitance sensor that detects contact with the lips, or a flow meter or flow switch that detects actual inhalation by the user.

[0017] The induction coil may be intermittently energized according to a predetermined heating profile, which may be selected by a user, for example, in real time via a wireless (e.g., Bluetooth) communication interface, or the predetermined heating profile may be selected automatically, for example, based on detected characteristics associated with the non-liquid flavor-releasing medium.

[0018] The electronic vapor inhaler may comprise a plurality of inductively heatable elements, the number of which may be selected to provide optimal heating of the non-liquid flavor-releasing medium. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional diagram of an example of an electronic vapor inhaler that can be operated according to the method of the present disclosure. [Figure 2] (a) is a schematic diagram of a pulsed heating profile in an inductively heatable element, showing intermittent heating and cooling of the inductively heatable element; (b) is a schematic diagram of the intermittent operation of an induction coil to generate the pulsed heating profile of (a); and (c) is a schematic diagram of the average operating temperature of a non-liquid flavor release medium provided by the pulsed heating profile of (a). DETAILED DESCRIPTION OF THE INVENTION

[0020] Embodiments of the present disclosure will now be described, by way of example only, and with reference to the accompanying drawings.

[0021] 1, electronic vapor inhaler 10 comprises a generally elongated housing 12 having a proximal end 14 and a distal end 16. Electronic vapor inhaler 10 includes a mouthpiece 18 at proximal end 14 through which a user can inhale vapor generated by heating a non-liquid flavor-releasing medium 30. Electronic vapor inhaler 10 includes a controller 20, e.g., in the form of a microprocessor, and a power source 22, e.g., in the form of one or more batteries that are inductively rechargeable.

[0022] The housing 12 includes a chamber 24 containing a non-liquid flavor-releasing medium 30. The chamber 24 is located at the proximal end 14 of the housing 12, adjacent the mouthpiece 18, although this is not strictly necessary and may be located at any suitable location between the proximal end 14 and the distal end 16. In the illustrated embodiment, the chamber 24 is formed within the housing 12 and is accessed by removing a cover 25 from the proximal end 14 of the housing 12, with which the mouthpiece 18 is integrally formed. In alternative embodiments, the chamber 24 may itself be formed as a removable component and may be accessed by removing that component from the housing 12.

[0023] In the illustrated embodiment, the non-liquid flavor-releasing medium 30 is embodied as a cartridge 26 that can be removably inserted into the chamber 24. The cartridge 26 includes an elongated inductively heatable element 28 and a non-liquid flavor-releasing medium 30 that can be adhered or fixed to the surface of the inductively heatable element 28. It will be understood that the embodiment of the electronic vapor inhaler 10 shown in FIG. 1 is provided merely by way of example to facilitate explanation of the method of operation according to the present disclosure. Other configurations, such as those using multiple inductively heatable elements, each of which has a different geometric shape, and in which the cartridge 26 is replaced by a breathable capsule containing the non-liquid flavor-releasing medium 30 and one or more inductively heatable elements 28, are fully within the scope of the present disclosure.

[0024] The non-liquid flavor-releasing medium 30 typically comprises a tobacco material, although other non-liquid flavor-releasing products can be used. The non-liquid flavor-releasing medium 30 is typically impregnated with a vapor-forming medium, such as propylene glycol, glycerol, or a combination of both, and when heated to a temperature within the operating temperature range, produces a vapor that is inhaled by a user through the mouthpiece 18 of the electronic vapor inhaler 10.

[0025] The electronic vapor inhaler 10 includes an induction heating device 34 that includes an induction coil 36 that can be energized by the power supply 22. As will be appreciated by those skilled in the art, energizing the induction coil 36 creates an alternating electromagnetic field that generates eddy currents in the inductively heatable element 28, causing the inductively heatable element 28 to heat. Heat is then transferred from the inductively heatable element 28 to the non-liquid flavor-releasing medium 30 by, for example, conduction, radiation, and convection, thereby heating the non-liquid flavor-releasing medium 30. Operation of the induction heating device 34 is controlled by the controller 20, which will be described in more detail below.

[0026] 2(a)-(c), when the electronic vapor inhaler 10 is activated by a user, the controller 20 causes the induction heating device 34, and more specifically the induction coil 36, to be intermittently energized by the power supply 22. This intermittent or pulsed operation is clearly shown in FIG. 2(b). The intermittent or pulsed operation of the induction coil 36 is represented by "on" and "off" pulses. This intermittent or pulsed operation causes the induction coil 36 to generate an intermittent or pulsed alternating electromagnetic field, which in turn provides pulsed heating and cooling of the inductively heatable element 28. The pulsed heating and cooling of the inductively heatable element 28 is clearly shown in FIG. 2(a), which illustrates the temperature change of the inductively heatable element 28 over time. The pulsed heating and cooling characteristics can be influenced by controlling the pulse frequency (i.e., the number and / or length of pulses within a given time period) of the power supplied to the induction coil 36, for example, as shown in FIG. 2(b). Alternatively, or in addition, the pulsed heating and cooling characteristics can be influenced by controlling the pulse amplitude of the power supplied to the induction coil 36 and / or by varying the duty cycle of the power supplied to the induction coil 36.

[0027] As shown in FIG. 2( a ), the pulsed heating and cooling of the inductively heatable element 28 heats the non-liquid flavor-releasing medium 30 , and particularly localized regions thereof, to an ambient temperature T A from, typically 18 The device is rapidly heated to an operating temperature T1 between 0°C and 220°C (see Figure 2(c)). The temperature T1 is significantly lower than the combustion temperature of typical tobacco materials (approximately 380°C), ensuring that tobacco Do not allow materials to overheat, burn, or combust.

[0028] The controller 20 may be configured to maintain the pulsed heating and cooling of the inductively heatable element 28 (by intermittently energizing the induction coil 36) throughout the duration of use of the electronic vapor inhaler 10 until it is stopped by the user, for example, when components of the non-liquid flavor-releasing medium 30 are depleted such that the vapor no longer has satisfactory characteristics, such as flavor and aroma.

[0029] Referring to FIG. 2(c), the pulse of the inductively heatable element 28 to achieve the operating temperature T1 is The rapid heating and cooling occurs during a first operational phase 40 after activation of the electronic vapor inhaler 10. This first operational phase 40 involves an initial heating of the non-liquid flavor-releasing medium 30, thereby raising the temperature of at least a localized region of the non-liquid flavor-releasing medium 30 to an ambient temperature T A to the temperature at which vapor suitable for inhalation is generated. After the end of the first operating phase 40, at the beginning of the second operating phase 42, the average temperature of the non-liquid flavor releasing medium 30 rises until it reaches a higher temperature T2. The typical duration of the first operating phase 40 is less than 10 seconds, more typically in the range of 5 seconds or less. It will be appreciated that this heating is much more rapid than the heating provided during the first phase of operation of the device described in the '661 patent (30-60 seconds), resulting in a more rapid start-up time and therefore the shortest possible "time to first puff."

[0030] During the second operational phase 42, the controller 20 can reduce the energy supplied by the power supply 22 to the induction coil 36 to reduce the strength of the electromagnetic field and thereby reduce the temperature of the inductively heatable element 28. This is possible because the components of the electronic vapor inhaler 10 have been heated during the first operational phase 40, reducing the amount of moisture and vapor-forming medium in the non-liquid flavor-releasing medium 30. Thus, even with the lower energy input to the induction coil 36, the non-liquid flavor-releasing medium 30 can be maintained at the average operating temperature T2. In the second operating stage 42 shown in (c), the operating temperature T2 of the non-liquid flavor releasing medium 30 is , is shown to remain relatively constant. However, the operating temperature of the non-liquid flavor releasing medium 30 may be increased or decreased during the second operating phase 42 to ensure that satisfactory flavors and aromas continue to be delivered to the user.

[0031] In one embodiment, during the second operational phase 42, the controller 20 controls the non-liquid flavor release by varying the pulse ratio of the power source 22 to the induction coil 36 based on the user's request. The electronic vapor inhaler 10 controls the amount of energy transferred to the medium 30. Among other things, the electronic vapor inhaler 10 may include means for detecting when a user is about to inhale or when an inhalation is actually occurring. For example, the electronic vapor inhaler 10 may include an accelerometer for detecting movement of the user to the lips, a capacitance sensor (a so-called lip detector) attached to the mouthpiece 18 for detecting when the mouthpiece is in contact with the user's lips, or a flow meter / flow switch for detecting when the user is actually inhaling through the mouthpiece 18. It will be understood that these detection means are provided merely as examples, and that other detection means are fully within the scope of the present disclosure.

[0032] In this embodiment, when the controller 20 receives a signal from the detection means indicating an impending or actual inhalation by the user, the controller 20 increases the energy supplied by the power supply 22 to the induction coil 36, which increases the temperature of the inductively heatable element 28 and, in turn, increases the temperature of the non-liquid flavor releasing medium 30. The controller 20 is also configured, upon receiving the signal from the detection means, to cause the power supply 22 to intermittently energize the induction coil 36, which causes the induction coil 36 to generate an intermittent alternating electromagnetic field, which in turn provides pulsed heating and cooling of the inductively heatable element 28.

[0033] If desired, the induction coil 36 may be intermittently energized (during the first operating phase 40 and / or the second operating phase 42) according to a predetermined heating profile. The predetermined heating profile may be selected by a user, for example, to provide a higher or lower operating temperature depending on the user's preferences and / or the characteristics of the non-liquid flavor-releasing medium 30. Alternatively, or in addition, the predetermined heating profile may be automatically selected based on detected characteristics associated with the non-liquid flavor-releasing medium 30.

[0034] Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to these embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the exemplary embodiments described above. Each feature disclosed in this specification, including the claims and drawings, may be replaced by an alternative feature serving the same, equivalent, or similar purpose, unless expressly stated otherwise.

[0035] Unless the context clearly dictates otherwise, in the specification and claims, the terms "comprises," "comprising," and the like are to be construed in an inclusive or exhaustive sense, as opposed to an exclusive sense, so-called "including but not limited to."

[0036] Any combination of the above-described features in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or clearly contradicted by context.

Claims

[Claim 1] 1. A method of operating an electronic vapor inhaler comprising an induction heating device, the induction heating device comprising an induction coil for generating an alternating electromagnetic field to heat an inductively heatable element and thereby heat a non-liquid flavor-releasing medium, the method comprising intermittently energizing the induction coil to generate an intermittent alternating electromagnetic field that provides pulsed heating and cooling of the inductively heatable element.

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