EA043259B1 - AEROSOL GENERATING DEVICE WITH POROUS CONVECTION HEATER - Google Patents

Description

Technical field

The invention generally relates to aerosol generating devices. In particular, the present invention relates to aerosol generating devices comprising a convection heating element.

Background of the invention

Aerosol generating devices typically use convection heaters that heat air that is used to heat the aerosol generating substrate to generate an aerosol or vapor. However, current convection heater configurations have several drawbacks. If the convection heater is in the form of a heating plate, the heating plate only allows a small air contact surface to be heated, and thus results in non-uniform and insufficient heating performance. Other configurations use a heating element in combination with a heat spreader that either distributes the heat generated by the heating element or diffuses the air heated by the heater to achieve more uniform heating of the aerosol generating substrate. This may further serve the purpose of helping to enable the heating element itself to be heated in a more uniform manner, so as to avoid thermal instability as much as possible. However, since the heat spreader is not an active heating element, the heating performance is insufficient.

Therefore, it is an object of the present invention to provide a convection heater that enables improved heating performance and/or more uniform heating of the heater.

The essence of the invention

The above object is achieved by the invention as defined by the features of the independent claims. Its preferred preferred embodiments are defined by the features of the dependent claims.

According to a first aspect, the present invention provides an aerosol generating apparatus comprising a chamber configured to at least partially accommodate an aerosol generating substrate, an air flow passage through the chamber, a convection heater located upstream of the chamber in the direction of flow along an air flow passage, and a heating element having a porous structure configured to cause air to flow through the air flow passage through the heating element to reach the chamber. The porous structure of the heating element provides a higher ratio of heating surface to volume, in contrast to the heating element in the form of a plate or pin. This allows efficient and uniform heating of the air passing through the porous structure.

In a first preferred embodiment according to the first aspect of the present invention, the heating element consists of or contains a sintered metal material. The use of a sintered metal material is advantageous because the sintering process already allows a porous structure to be obtained without the need for machining steps, such as when trying to create a porous structure from a single piece of metal material.

In a second preferred embodiment according to any of the previous embodiments of the present invention, the heating element comprises a metal material having a low temperature coefficient of resistance a. Having a lower temperature coefficient of resistance means that even when the metal material is heated, the electrical resistance of the metal materials does not change much. This is advantageous because it inhibits hot spots in the heating elements and thus reduces the chance of thermal instability that could lead to fatal heater failure and/or heat damage to the aerosol generating device and potentially to the user of the aerosol generating device.

In the third preferred embodiment according to any of the previous embodiments of the present invention, the temperature coefficient of resistance α is 0.0000 to 0.001, preferably 0.0000 to 0.0009, more preferably 0.0000 to 0.0008, even more preferably from 0.0000 to 0.0007, even more preferably from 0.0000 to 0.0006, even more preferably from 0.0000 to 0.0005, even more preferably from 0.0000 to 0.0004, even more preferably from 0.0000 to 0.0003, even more preferably 0.0000 to 0.00025, even more preferably 0.0000 to 0.0002, even more preferably 0.0000 to 0.00015.

In a fourth preferred embodiment according to any of the preferred embodiments of the present invention, the first to third metallic material comprises stainless steel, NiCr, CuNi, NiCrAl and/or SiCrN, preferably NiCr.

In a fifth preferred embodiment according to any of the previous embodiments of the present invention, the aerosol generating device comprises a component

- 1 043259 in the form of a conductive heater, configured to heat at least some parts of the aerosol-forming substrate. By providing an additional conductive heater, the aerosol generating device can generate an aerosol from aerosol generating substrates that require or prefer conductive heating, such as, for example, tobacco based aerosol generating substrates.

In a sixth preferred embodiment according to any of the previous embodiments of the present invention, the heating element is provided with a first electrode which is a bias plate and a second electrode which is a ground plate. By providing a bias contact and a plate-like ground contact, more uniform heating of the heating element can be achieved due to a more spatially uniform current flow through the heating element. By way of example, a voltage greater than 3V, preferably greater than 4V, more preferably greater than 5V, most preferably greater than 6V may be applied to the bias plate.

In the seventh preferred embodiment according to the sixth preferred embodiment of the present invention, the heating element is located between the bias plate and the ground plate. This further enables more uniform heating of the heating element due to the more uniform electric field due to this arrangement.

In an eighth preferred embodiment according to any of the sixth to seventh preferred embodiments of the present invention, at least one of the bias plate and the ground plate has pores configured to allow air to flow through the bias plate and/or the ground plate. By providing pores in the bias plate and/or ground plate, air can flow through the heating element from the sides where the bias plate and/or ground plate are provided, thereby increasing the airflow rate through the heating element.

In the ninth preferred embodiment according to the previous embodiments, the porosity of the bias plate and/or the ground plate is greater than the porosity of the porous structure of the heating element, and in the tenth preferred embodiment according to any of the eighth or ninth preferred embodiments of the present invention, the average pore size bias plate and/or ground plate is larger than the average pore size of the porous structure of the heating element. These two embodiments are advantageous because they allow the heating element to be the rate limiting factor for the rate of air flow through the heating element rather than the bias plate and/or ground plate, thus providing sufficient air to pass through the heating element.

In an eleventh preferred embodiment according to one of the preferred embodiments of the present invention, the seventh to tenth bias plate is provided with a bias connection located substantially in the center of the bias plate.

In a twelfth preferred embodiment according to any of the seventh to eleventh preferred embodiments of the present invention, the ground plate is provided with one or more ground connections that ground the ground plate, wherein the one or more ground connections are located at one or more locations around the circumference of the ground plate. plates. The ground connections can help provide an improved or more stable ground connection for the ground plane.

In the thirteenth preferred embodiment according to the fourteenth embodiment, the ground plate is provided with one or more ballast resistors located at locations corresponding to one or more ground connections. Ballast resistors provided with earth connections improve the reliability and durability of the heating element because the ballast resistors compensate for the difference in current at each earth connection and thus provide a more uniform spatial current flow through the heating element and thus more uniform spatial heating of the heating element. .

In a fourteenth preferred embodiment according to any of the previous embodiments of the present invention, the porous structure is a microporous structure.

In the fifteenth preferred embodiment according to the fourteenth preferred embodiment of the present invention, the average pore size of the porous structure of the heating element is in the range of 0.025±0.02 mm, preferably 0.025±0.01 mm, more preferably 0.025±0.005 mm, most preferably 0.025± 0.0025 mm.

- 2 043259

In a sixteenth preferred embodiment according to any of the tenth to thirteenth preferred embodiments of the present invention, the average pore size of the ground plate and/or bias plate is 100-400 µm, preferably 150350 µm, more preferably 175-325 µm, even more preferably 200 -300 µm, even more preferably 225-275 µm and most preferably 240-260 µm.

Brief description of graphic materials

In FIG. 1 is a schematic cross-sectional view of an aerosol generating device with a convection heater in accordance with embodiments of the present invention;

in fig. 2A is a schematic perspective view of a convection heater in accordance with embodiments of the present invention;

in fig. 2B, 2C, and 2D are schematic plan views of a bias plate, a ground plate, and a heating element, respectively, according to embodiments of the present invention.

Detailed description

Preferred embodiments of the present invention are described hereinafter and in connection with the accompanying drawings.

As illustrated in FIG. 1, aerosol generating device 100 may include a housing 110. Housing 110 is configured to receive a chamber 120 that may at least partially accommodate an aerosol generating substrate 105 for generating aerosol in chamber 120. Chamber 120 may be is open on one side of the aerosol generating device 100, whereby the aerosol generating substrate 105 can be at least partially inserted into the chamber 120. The aerosol generating substrate 105 can be any substrate suitable for an e-vapor vapor aerosol. or t-vapor. The aerosol forming substrate 105 may contain tobacco material in various forms such as cut tobacco and tobacco granules, and/or the tobacco material may contain tobacco leaf and/or reconstituted tobacco if suitable for t-vapor type vapor.

The aerosol generating device 100 includes a convection heater 200 that is located upstream of the airflow passage through the chamber 120. The airflow passage may, for example, be formed by an opening located opposite the side of the housing 110 on which an opening may be provided to at least partially accommodate the aerosol generating substrate 105. Additionally or alternatively, although not shown in the drawings, the airflow passage may also be provided by one or more airflow channels provided in the housing, which extend from an inlet open outward relative to the aerosol generating device 100, at any suitable location, up to an outlet located upstream of the convection heater 200 such that at least a portion of the air exiting the outlet passes through the convection heater 200. The convection heater 200 may be a convection heater as described below in the context of FIG. 2A, 2B, 2C and 2D. Additionally, a conductive heater 150 may be provided, whereby the aerosol-forming substrate at least partially located in the chamber 120 is heated by conductive heat exchange. This can be achieved by the conductive heater 150, whereby the conductive heater 150 heats at least some portions of the aerosol-forming substrate directly. Additionally or alternatively, a conductive heater may be provided such that the conductive heater 150 heats the chamber wall 120, whereby the chamber wall heats at least some portions of the aerosol-forming substrate by conductive heat exchange. The conductive heater 150 may be any type of heater that is suitable for heating the aerosol generating substrate directly or indirectly. For example, the conductive heater 150 may be a film heater comprising an electrically conductive heating track for resistive heating and one or more base layers containing an insulating material. The insulating material may be a polymeric material such as polyimide, silicone and/or PEEK.

The aerosol generating device may further comprise a portable power source 130, such as a battery, for supplying power to the aerosol generating device to generate an aerosol. Furthermore, a control circuit 140 may be provided to control any function for operating and/or controlling the aerosol generating device 100. To enable the portable power supply 130 to be charged by any suitable means, a charging connector 141 may be provided. Additionally or alternatively, the portable power supply 130 may be replaceable/removable.

As illustrated in FIG. 2A-2D, the convection heater 200 includes a heating element 210 with a porous structure. Although the porous structure heating element 210 is shown to be substantially in the form of a plate with a circular base shape, the heating element may be of any shape or form suitable for heating the air passing through the heating element.

- 3 043259 element 210. Depending on the configuration and dimensions of the aerosol generating device 100 and/or the chamber 120, the heating element 210 may alternatively have, for example, a pin shape, a cube shape, or a ball shape. The heating element 210 with the porous structure 210 includes a plurality of heating element pores 211 that allow air to pass through the heating element 210. The heating element 210 may be composed of or contain a sintered metal material. The metallic material may be any metallic material with a low temperature coefficient of resistance a. The drag coefficient α may be from 0.0000 to 0.001, preferably from 0.0000 to 0.0009, more preferably from 0.0000 to 0.0008, even more preferably from 0.0000 to 0.0007, even more preferably from 0 .0000 to 0.0006, even more preferably 0.0000 to 0.0005, even more preferably 0.0000 to 0.0004, even more preferably 0.0000 to 0.0003, even more preferably 0.0000 up to 0.00025, even more preferably 0.0000 to 0.0002, most preferably 0.0000 to 0.00015. The metallic material may comprise stainless steel, NiCr, CuNi, NiCrAl and/or SiCrN, preferably NiCr, or any metallic material with similar characteristics. The pores 211 of the heating element may be substantially the same size and/or substantially the same shape. Each of the pores 211 of the heating element may have a different size and/or different shape. The average pore size of the porous structure of the heating element 210 may be in the range of 0.025±0.02 mm, preferably 0.025±0.01 mm, more preferably 0.025±0.005 mm, most preferably 0.025±0.0025 mm.

The bias plate 220 may be provided on the first side of the heating element 210, and the ground plate 230 may be provided on the second side opposite the first side of the heating element. While the bias plate 220 and ground plate 230 are shown to be substantially plate-shaped and substantially cover the entire first or second side of the heating element 210, they may be of any suitable shape and size and cover the entire first and/or second side of the heating element 210 or only part of them. In addition, the bias plate may be provided on any side of the heating element 210 where the ground plate is not provided. As shown in FIG. 2A, the thickness of the bias plate 220 is less than the thickness of the heating element 210; preferably the thickness of the bias plate 220 is no more than 80%, more preferably no more than 70%, even more preferably no more than 60%, and most preferably no more than 50% of the thickness of the heating element 210. This will minimize the chance of any cooling of the air before reaching them a tobacco product. The bias plate 220 and/or ground plate 230 may include a plurality of pores 221/231 configured to allow air to flow through the bias plate and/or ground plate. The bias plate pores 221 and/or the ground plate pores 231 may each be substantially the same size and/or substantially the same shape. Alternatively, each of the bias plate pores 221 and/or the ground plate pores 231 may be of a different size and/or shape. Additionally, the porous structure of the bias plate, with respect to any of the size, shape, and/or average size of the plurality of pores, may be the same or different than the porous structure of the ground plate.

The porosity of the bias plate 220 and/or the ground plate 230 may be greater than the porosity of the porous structure of the heating element. In addition, the average pore size of the plurality of pores 221/231 of the bias plate 220 and/or ground plate 230 may be larger than the average pore size of the porous structure of the heating element 210. Additionally, the bias plate may be contacted via a substantially centrally located bias connection 222. displacement plate. The bias plate may also be contacted via one or more bias connections 222 at one or more locations.

The ground plate may be provided with one or more ground connections 232, which may be located at one or more locations around the outer circumference of the ground plate 230 to achieve a ground connection. Additionally, one or more ballast resistors 232 may be provided on the ground plate 230 at locations corresponding to the locations of one or more ground connections. While one or more ground connections 232 and/or one or more ballast resistors 232 are shown in FIG. 2A and 2C located at locations equidistant from each other around the outer circumference of the ground plate 230, one or more ground connections 232 and/or one or more ballast resistors 232 may be placed at any suitable location with any suitable spacing between positions around the outer circumference of the ground plane. plate 230, for example, if this is required due to the geometric or structural parameters of the heating element 210 and/or chamber.

It should be noted that any of chamber 120, heater 200, heating element 210, bias plate 220, ground plate 230, or any combination thereof, may instead of the circular base shown in FIG. 2A-2D, have any suitably shaped base, such as an elliptical, rectangular, polygonal base profile, or an irregularly shaped base profile.

Although the present invention describes certain embodiments and generally related methods, variations and transformations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of exemplary embodiments does not define or limit the present invention. Other modifications, substitutions and changes are also possible without departing from the scope of the present invention as defined by the independent and dependent claims.

List of reference numerals used on graphics

100: an aerosol generating device;

105: aerosol-forming substrate;

110: body;

120: camera;

130: power supply;

140: PCB/control circuit;

141: charging connector;

150: conductive heater;

200: convection heater;

210: heating element with porous structure;

211: heating element pores;

220: offset plate;

221: pore of the bias plate;

222: offset connection;

230: ground plate;

231: ground plate pores;

232: ground connection/ballast resistor.

Claims (10)

1. An aerosol generating device, comprising: a chamber configured to at least partially accommodate an aerosol generating substrate; an air flow passage through the chamber; a convection heater located upstream of the chamber in the direction of flow along the flow passage and containing a heating element having a porous structure designed in such a way that air is caused to flow through the flow passage through the heating element to reach the chamber, wherein the heating element consists of or contains a sintered metal material. 2. The aerosol generating device according to the preceding claim, characterized in that the temperature coefficient of resistance α of the metallic material is 0.0000 to 0.001, preferably 0.0000 to 0.0009, more preferably 0.0000 to 0.0008, even more preferably 0.0000 to 0.0007, even more preferably 0.0000 to 0.0006, even more preferably 0.0000 to 0.0005, even more preferably 0.0000 to 0.0004, still more preferably 0.0000 to 0.0003, even more preferably 0.0000 to 0.00025, even more preferably 0.0000 to 0.0002, even more preferably 0.0000 to 0.00015. 3. An aerosol generating device according to any one of claims 1, 2, characterized in that the metallic material comprises stainless steel, NiCr, CuNi, NiCrAl and/or SiCrN, preferably NiCr. 4. An aerosol generating device according to any one of the preceding claims, characterized in that it comprises a conductive heater component configured to heat at least some portions of the aerosol generating substrate. 5. An aerosol generating device according to any one of the preceding claims, characterized in that the heating element is provided with a first electrode which is a bias plate and a second electrode which is a ground plate. 6. An aerosol generating device according to claim 5, characterized in that at least one of the bias plate and the ground plate contains pores configured to allow air to flow through the bias plate and/or the ground plate. 7. The aerosol generating device according to the preceding claim, characterized in that the porosity of the bias plate and/or the ground plate is greater than the porosity of the porous structure of the heating element, and/or the average pore size of the bias plate and/or the ground plate is greater than the average pore size of the porous structure of the heating element. element. 8. An aerosol generating device according to any one of claims 5 to 7, characterized in that the grounding - 5 043259 the plate is provided with one or more ground connections that ground the ground plate, wherein one or more ground connections are located in one or more places around the circumference of the ground plate. 9. An aerosol generating device according to the preceding claim, characterized in that the ground plate is provided with one or more ballast resistors located at locations corresponding to one or more ground connections. 10. An aerosol generating device according to the preceding claim, characterized in that the average pore size of the porous structure of the heating element is in the range of 0.025±0.02 mm, preferably 0.025±0.01 mm, more preferably 0.025±0.005 mm, most preferably 0.025 ±0.0025 mm, and/or the average pore size of the ground plate and/or bias plate is 100-400 µm, preferably 150-350 µm, more preferably 175-325 µm, even more preferably 200-300 µm, even more preferably 225 -275 µm and most preferably 240-260 µm.