Heating device for an aerosol-generating device

Abstract

The invention relates to a heating device (100) for an aerosol-generating device (1), comprising at least one heating element (101, 101') and a sleeve (102), in particular a sleeve with a cylindrical design, wherein the sleeve (102) has a first section (103) and a second section (104), the sleeve has a heat exchanger structure (105) in the first section (103), and the sleeve has a chamber for receiving a solid or liquid material, in particular a tobacco stick, in the second section (102). At least one flow channel (106) is introduced into the heat exchanger structure (105). The first section (103) is arranged in front of the second section (104) in the flow direction ((I)) such that when a user inhales, a fluid flows first through the flow channel of the heat exchanger structure (105) and then through the chamber. The at least one heating element (101, 101') is arranged with respect to the first section (103) of the sleeve (102) such that the heating element (101, 101') heats the fluid flowing through the flow channel of the heat exchanger structure (105) in the flow direction ((I)) in order to release ingredients from the material upon flowing through the chamber, and the heat exchanger structure (105) is designed such that a specified flow resistance of the fluid is achieved when the fluid flows through the flow channel of the heat exchanger structure (105).

Description

[0001] Heating device for an aerosol generating device

[0002] The invention relates to a heating device for an aerosol generating device. Furthermore, the invention relates to an aerosol generating device comprising the heating device according to the invention.

[0003] The tobacco industry uses various approaches to address the health risks associated with tobacco consumption. These include methods in which a liquid is vaporized, after which the resulting aerosol can be inhaled by the consumer. A variety of handheld vapor-generating devices for consumption, referred to below as aerosol generating devices, are known from the prior art. What all of these aerosol generating devices have in common is that they are designed to accommodate a consumable product containing a solid or liquid medium that is heated by the aerosol generating device so that it assumes a gaseous state or an aerosol form. This vapor is then inhaled by a consumer or user.

[0004] Other products forgo heating substances altogether. In so-called heat-not-burn (HnB) applications, specially manufactured tobacco sticks (HTU = "Heated Tobacco Unit") are heated to a temperature far below the normal burning temperature of, for example, a cigarette. While various ingredients are released from the HTU (e.g., flavorings, active ingredients, etc.), the significantly lower temperatures are said to release fewer harmful substances compared to conventional combustion.

[0005] Heating the HTU can be accomplished in various ways. Common methods include inserting an electrically heated element into the HTU, inductive heating of a susceptor located within the HTU, or heating a sleeve located on the outside of the HTU. Important parameters for all of these heating methods are temperature homogeneity and accuracy throughout the entire HTU range, as well as the response time and dynamics of the temperature behavior. While the temperature inside the HTU should enable the extraction of the desired substances, the target temperature should not be exceeded in any area to the point where harmful combustion products are formed. Due to the generally low thermal conductivity of the HTU, temperature control and regulation are of central importance.Since such HnB devices are generally designed to be portable, it is also desirable to minimize the power consumption of an ideal heating system as much as possible.

[0006] Furthermore, users want to feel a resistance when pulling on the devices, similar to that experienced when pulling on traditional cigarettes.

[0007] The invention is based on the object of presenting a heating device which makes it possible to heat a material in an aerosol generating device evenly and dynamically and at the same time to generate a proven draft feeling for a user.

[0008] The object is achieved by a heating device according to patent claim 1 and by an aerosol generating device according to patent claim 14.

[0009] With regard to the heating device, it is provided that it is intended for an aerosol generating device and comprises at least one heating element and a sleeve, wherein the sleeve has a first section and a second section, wherein the sleeve has a heat exchanger structure in the first section, wherein the sleeve has a chamber in the second section for receiving a solid or liquid material, in particular a tobacco stick, wherein at least one flow channel is introduced into the heat exchanger structure, wherein the first section is arranged upstream of the second section in the flow direction, so that when a user draws a fluid, a fluid first flows through the flow channel of the heat exchanger structure and then through the chamber, wherein the at least one heating element is arranged in relation to the first section of the sleeve in such a way thatthat the at least one heating element heats the fluid flowing in the flow direction through the flow channel of the heat exchanger structure to release ingredients from the material as it flows through the chamber, and wherein the heat exchanger structure is designed such that a predetermined flow resistance of the fluid is achieved as it flows through the flow channel of the heat exchanger structure.

[0010] The heating device according to the invention thus achieves this objective by providing a heat exchanger structure arranged upstream of the chamber containing the material to be converted into the vapor phase. The heat exchanger structure transfers the heat generated by the heating element(s) to the fluid flowing through it, in particular air, which then contacts the material. The material is therefore not in direct contact with the heating element(s). Furthermore, the heat exchanger structure has a special internal design through the dimensioning of the flow channel, so that this flow channel forms a predetermined flow resistance for the fluid. The flow resistance ensures a noticeable resistance when the user draws, which can be dimensioned so that the user can compare their experience to traditional smoking or vaporizing products.

[0011] The material is a liquid (so-called "liquid") or a solid material (e.g., tobacco), whose corresponding ingredients can be converted into the vapor phase through heating. The ingredients that can be released from the material include, for example, flavors and / or active ingredients such as nicotine or medicinal substances such as aspirin.

[0012] The heating element itself attached to the heat exchanger structure can be designed in a variety of ways. For example, a heating element based on the principle of resistance heating or an inductively heatable heating element made of a susceptor material can be used. The use of other types of heating elements is also conceivable. Further developments of the heating device make it possible to increase the efficiency of heat transfer between the sleeve and the air flow by intensifying the mixing of the air flow and the interaction with the heat exchanger surface. The interior of the heat exchanger structure is specially designed for this purpose. Three variants are presented below:

[0013] According to a first variant of the heating device, the heat exchanger structure is designed such that at least one passive fluidic valve is arranged in the flow channel, wherein the passive fluidic valve is arranged in the flow channel such that the fluid flows through the passive fluidic valve in a blocking direction of the passive fluidic valve. Passive fluidic valves are valves that do not contain any moving mechanical parts. Such a valve has a preferred direction and a blocking direction. In the blocking direction, the flow resistance of the fluid flowing through the valve is significantly higher than in the preferred direction. They are therefore also referred to as fluidic diodes. Such valves are typically used to conduct fluids in (micro)fluidic systems and to specify a flow direction.In the case of the invention, however, the flow resistance is used to create the preferred draw sensation for the user. Furthermore, such valves create turbulence in the mostly laminar flow profile to achieve a homogeneous heat distribution in the fluid.

[0014] One embodiment provides for the passive fluidic valve to consist of Tesla elements, nozzles, diffusers, or a combination thereof. All of these elements have a preferred direction and a blocking direction and generate turbulence when flowing through in the blocking direction. The predetermined flow resistance can be adjusted by arranging several passive fluidic valves in series and / or by dimensioning the respective passive fluidic valves. The exact dimensioning and its effect on the flow resistance depends on the type of valve. According to a second variant of the heating device, the heat exchanger structure is designed such that the flow channel has a spiral course. In this case, it is advantageous for the spiral course of the flow channel to comprise one or more complete turns.The windings create turbulence in the flow profile and therefore improve the homogeneity of the heat distribution in the flow profile.

[0015] It is advantageous if the flow channel is routed along the outer wall of the sleeve. The outer wall of the sleeve is typically in contact with the heating element(s) and is therefore heated. By routing the flow channel along the outer wall, the heat can be effectively transferred to the fluid. Advantageously, the flow channel is designed such that the surface of the flow channel facing the outer wall is maximized relative to the inner surface. In such a case, the flow channel does not have a round cross-section.

[0016] In this variant, the predetermined flow resistance can be adjusted by adjusting the number of channels and / or the channel geometry, particularly the diameter and length, or the number of turns. The smaller the diameter, and thus the cross-section, of the flow channel, the higher the flow resistance. The flow resistance also increases with the length of the flow channel.

[0017] According to a third variant of the heating device, the heat exchanger structure is designed such that the heat exchanger structure comprises at least one lamella or rib arranged in the flow channel. A lamella or rib is a structure which is inserted into the flow channel and spans a surface orthogonal to the direction of flow, thereby locally narrowing the flow channel. This also creates the turbulence already described and achieves the effects caused thereby. An advantageous embodiment provides for at least two lamellae or ribs arranged in the flow channel, wherein the lamellae or ribs are designed and arranged in the flow channel in such a way that the lamellae or ribs each form an opening between the lamellae or rib and the wall through which the fluid flows, and that the arrangement of the openings between a lamellae or rib and the lamella or rib following it.The openings are designed in such a way that the area of ​​each opening is advantageously smaller than the area spanned by the fin or fin in the flow channel. Alternating means that the position of an opening in the channel (viewed from the orthogonal cross-section of the flow channel) changes and alternates with each fin or fin.

[0018] In this variant, the predetermined flow resistance can be adjusted by adjusting the size and number of the openings. The flow resistance increases with increasing number of openings (and thus increasing number of fins / louvres) and decreasing size or area of ​​the openings.

[0019] An advantageous embodiment provides that the lamella or rib is designed and mounted in the flow channel in such a way that the lamella or rib is inclined against the flow direction. This increases the number and intensity of the turbulence.

[0020] An advantageous embodiment of the heating device provides that the at least one heating element is in thermal contact with the outer wall of the heat exchanger structure. As a result, the heat generated by the heating element(s) is transferred to the outer wall of the heat exchanger structure and from there into the fluid. It is advantageous if at least the outer wall is made of a material with high thermal conductivity, e.g., a metallic or suitable ceramic material. With regard to the aerosol generating device, it is provided that it has a heating device according to the invention. The aerosol generating device further comprises a housing into which the aerosol generating device is inserted.The housing contains a recess for inserting the material to be vaporized and, optionally, an attachment on which the user can pull to inhale the material (in the case of a tobacco stick, no attachment is required, as the user inhales through the tobacco stick). Also located within the housing are an electronics unit and a battery unit, which controls the heating element and supplies it with electrical energy. Furthermore, one or more control elements (e.g., for switching the aerosol generation device on and off) can be arranged on the housing.

[0021] The invention is explained in more detail with reference to the following figure.

[0022] Fig. 1: first embodiment of an aerosol generating device according to the invention;

[0023] Fig. 2: a first embodiment of a heat exchanger structure used in the aerosol generating device;

[0024] Fig. 3: a second embodiment of a heat exchanger structure used in the aerosol generating device;

[0025] Fig. 4 is a cross-sectional view of the heat exchanger structure of the second embodiment;

[0026] Fig. 5: a third embodiment of a heat exchanger structure used in the aerosol generating device; and

[0027] Fig. 6: a fourth embodiment of a heat exchanger structure used in the aerosol generating device. An aerosol generating device 1 according to the invention is depicted as an example in Fig. 1. The aerosol generating device comprises a housing 110 having an outlet at one end region. The outlet is part of a recess 120 and serves to receive aerosols generated by the aerosol generating device 1 by a user. The recess 120 serves to supply a liquid or solid material, e.g., in stick form or as a liquid tank, to a cylindrical sleeve 102. The material contains active ingredients, e.g., nicotine or aspirin.

[0028] The cylindrical sleeve 102 comprises a first section 103 and a second section 104. The material is introduced into the second section 104. The first section 103 comprises a heat exchanger structure 105.

[0029] The aerosols are generated by two heating elements 101, 101' thermally connected to an outer wall 107 of the sleeve, which emit heat. The heating elements 101, 101' are mounted at different positions (e.g., top and bottom) of the outer wall 107. This heat is supplied by the heat exchanger structure 105 to a fluid, in particular air, which flows through a flow channel 106, 106' of the heat exchanger structure 105 when the user inhales or draws air. The heated fluid then flows through the material, dissolving ingredients and transporting them to the outlet of the aerosol generating device 100.

[0030] In all figures shown here, the fluid flows in flow direction v.

[0031] The heating elements 101, 101' are, in particular, resistance heating elements or inductively heatable heating elements. A heating element 101, 101' can be switched on and off by a control unit 130. The control unit 130 and the heating elements 101, 101' are supplied with the electrical energy required for operation by a power supply unit 140, in particular a battery or an accumulator. Although, for reasons of efficiency (reduced response time), two heating elements 101, 101' are used in this exemplary embodiment, the use of a single heating element or more than two heating elements is also possible. The heat exchanger structure 105 must have certain properties in order to be able to generate optimal heating of the flowing fluid and a draw resistance familiar to users of conventional cigarettes.The dimensions underlying a typical aerosol generation device 1, as well as the properties of the fluid to be heated (air), mean that for physically relevant flow velocities, the flow inside the heat exchanger structure 105 is predominantly laminar. Therefore, mixing of the fluid is crucial for efficient heat transfer, so that the formation of warm boundary layers on the flow channel walls can be counteracted.

[0032] Fig. 2 shows a first embodiment of the heat exchanger structure 105. The heat exchanger structure 105 is enclosed by the outer walls 107 of the first section 103 of the sleeve 102. The heat exchanger structure 105 comprises a flow channel 106 through which the fluid flows in the flow direction v when the user pulls. In this exemplary embodiment, fins L1, L2, ..., Ln are introduced into the flow channel 106. These are designed and attached to the outer walls 107 such that some of the fins L1, L2, ..., Ln are inclined counter to the flow direction v. This stimulates mixing of the fluid by generated turbulence (see the arrows indicating the mixing), so that the heat distribution in the fluid is optimized by the heat radiated from the outer walls. However, since the flow regime is expected to be laminar, further optimizations can be implemented.

[0033] Fig. 3 shows a special arrangement of the fins L1, L2, ..., Ln for this purpose. The fins are arranged in the flow channel 106 and connected to the outer wall 107 in such a way that the fluid must flow through narrow openings O1, O2, ..., On when the user pulls. Fig. 4 shows the cross-section of the heat exchanger structure 105 or the sleeve 102 in the first section 103. The fins L1, L2, ..., Ln are arranged in such a way that the position of the opening O1, O2, ..., On changes from one fin to the next. In the present example, the openings O1, O2, ..., On are arranged alternately, i.e. they repeat alternately. This forces the deflection of the fluid flow even in laminar flow. This results in a pressure loss, which is perceived by the user as a desired resistance to tension, which can be adjusted by the number and size of the openings 01, 02, ..., On.Furthermore, the geometry shown has less “dead volume” compared to the embodiment shown in Fig. 2, which intensifies the interaction with the outer wall 107 heated by the heating element 101.

[0034] In Fig. 5, the flow channel 106 is designed such that two Tesla valves V1, V2 are formed within it. Two-dimensional Tesla valves V1, V2 are known from fields of microfluidics, where similar issues are often addressed. Tesla valves belong to the class of microfluidic passive valves, i.e. structures whose geometry allows for easier flow in one direction (preferred direction) compared to the other direction (blocked direction). In the case of the Tesla valve, this is achieved by partially redirecting the flow direction. The principle of redirection and recombination of the volume flow ensures uniform heat distribution in the fluid.

[0035] In this embodiment, the fluid flows through the two valves V1, V2 in the blocking direction. This creates a higher flow resistance when flowing through than in the opposite direction. The exact level of this flow resistance, and the associated desired draw resistance perceived by the user, can be adjusted by selecting the dimensions, number of bypasses in the valves V1, V2 and number of valves V1, V2 themselves. For the embodiment shown in Fig. 5, the known two-dimensional Tesla valves are adapted to a cylindrical component. This achieves maximum mixing in the laminar state, which also maximizes heat transfer.

[0036] A final embodiment is shown in Fig. 6. Here, the fluid is transported in two spiral-shaped flow channels 106, 106' along the heated outer wall 107. It goes without saying that the person skilled in the art will provide more or fewer than two flow channels 106, 106' depending on requirements. The pressure loss, which the user perceives as desired drag resistance, can be adjusted here by the dimensions of the individual flow channels. Furthermore, heat transfer is optimized by designing the channel geometry such that the surface of a flow channel 106, 106' facing the outer wall 107 is maximized in relation to the inner surface. In the present example, the cross-section of the flow channels is therefore not round, but D-shaped.

[0037] It goes without saying that the invention is not limited to the listed embodiments. Those skilled in the art can modify or supplement the dimensions of the individual structures as required. It is also possible to connect several of the embodiments of the heat exchanger structure 105 in series or parallel.

[0038] List of reference symbols

[0039] 1 aerosol generating device

[0040] 100 heater

[0041] 101 Heating element

[0042] 102 sleeve

[0043] 103 first section of the sleeve

[0044] 104 second section of the sleeve

[0045] 105 Heat exchanger structure

[0046] 106, 106' flow channels

[0047] 107 Exterior wall

[0048] 110 housings

[0049] 120 recess

[0050] 130 control unit

[0051] 140 power supply unit

[0052] L1, L2, Ln slats

[0053] 01 , 02, ... , On openings

[0054] V1, V2 valves v flow direction

Claims

Patent claims 1 . Heating device (100) for an aerosol generating device (1), comprising at least one heating element (101, 102) and a sleeve (102), in particular of cylindrical design, wherein the sleeve (102) has a first section (103) and a second section (104), wherein the sleeve has a heat exchanger structure (105) in the first section (103), wherein the sleeve has a chamber for receiving a solid or liquid material, in particular a tobacco stick, in the second section (104), wherein at least one flow channel (106, 106') is introduced into the heat exchanger structure (105), wherein the first section (103) is arranged upstream of the second section (104) in the flow direction (v), so that when a user draws a fluid, a fluid first flows through the flow channel (106, 106') of the heat exchanger structure (105) and then through the chamber, wherein the at least one heating element (101 , 10T) is arranged relative to the first portion (103) of the sleeve (102),that the at least one heating element (101, 101') heats the fluid flowing in the flow direction (v) through the flow channel (106, 106') of the heat exchanger structure (105) to dissolve ingredients from the material as it flows through the chamber, and wherein the heat exchanger structure (105) is designed such that a predetermined flow resistance of the fluid is achieved as it flows through the flow channel (106, 106') of the heat exchanger structure (105).

2. Heating device according to claim 1, wherein the heat exchanger structure (105) is designed such that at least one passive fluidic valve (V1, V2) is arranged in the flow channel (106), wherein the passive fluidic valve (V1, V2) is arranged in the flow channel (106) such that the fluid flows through the passive fluidic valve (V1, V2) in a blocking direction of the passive fluidic valve (V1, V2).

3. Heating device according to claim 2, wherein the passive fluidic valve (V1, V2) consists of Tesla elements, nozzles, diffusers or a combination thereof.

4. Heating device according to claim 2 or 3, wherein the predetermined flow resistance is set by a series of several passive fluidic valves (V1, V2) and / or by dimensioning the respective passive fluidic valves (V1, V2).

5. Heating device according to claim 1, wherein the heat exchanger structure (105) is designed such that the flow channel (106, 106') has a spiral course.

6. Heating device according to claim 5, wherein the spiral course of the flow channel (106, 106') comprises one or more complete turns.

7. Heating device according to claim 5 or claim 6, wherein the flow channel (106, 106') is guided along the outer wall (107) of the heat exchanger structure (105).

8. Heating device according to one of claims 5 to 7, wherein the flow resistance is adjusted by the number of channels and / or the channel geometry, in particular the diameter and the length, or the number of turns.

9. Heating device according to claim 1, wherein the heat exchanger structure (105) comprises at least one lamella (L1, L2, ..., Ln) or fin arranged in the flow channel (106).

10. Heating device according to claim 9, wherein the heat exchanger structure (105) comprises at least two fins (L1, L2, ..., Ln) or ribs arranged in the flow channel (106), wherein the fins (L1, L2, ..., Ln) or ribs are designed and arranged in the flow channel (106) in such a way that the fins (L1, L2, ..., Ln) or ribs each form an opening (O1, O2, ..., On) between the fin (L1, L2, ..., Ln) or rib and the wall, through which the fluid flows, and that the arrangement of the openings (O1, O2, ..., On) between a lamella (L1, L2, ..., Ln) or rib and the lamella (L1, L2, ..., Ln) or rib following this is alternating.

11. Heating device according to claim 10, wherein the flow resistance is adjusted by the size and number of the respective openings (01, 02, ..., On).

12. Heating device according to claim 9, wherein the lamella (L1, L2, ..., Ln) or rib is designed and mounted in the flow channel (106) in such a way that the lamella (L1, L2, ..., Ln) or rib is inclined opposite to the flow direction (v).

13. Heating device according to one of the preceding claims, wherein the at least one heating element (101, 101') is in thermal contact with the outer wall (107) of the heat exchanger structure (105).

14. Aerosol generating device (1) comprising a heating device (100) according to one of claims 1 to 13.

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