CN118302069A - Method of forming tubular heater - Google Patents

Abstract

A method of forming a tubular heater (6) for an aerosol-generating system, the method comprising: providing a heat pipe (61); providing a flexible heating element (62); at least partially defining a heat pipe (61) with a flexible heating element (62); clamping the flexible heating element (61) to the heat conducting tube (61) with a clamping clamp (300); and heating the clamped heat conducting tube (61) and the flexible heating element (62).

Description

Method of forming tubular heater

Technical Field

The present disclosure relates to a method of forming a tubular heater for an aerosol-generating system. More specifically, the present disclosure relates to a method of forming a tubular heater for an aerosol-generating system.

Background

It is known to provide an aerosol-generating device for generating an inhalable aerosol. Such devices may heat the aerosol-forming substrate to a temperature that volatilizes one or more components of the aerosol-forming substrate without combusting the aerosol-forming substrate. Vapor generated from the heated aerosol-forming substrate forms an aerosol when cooled before reaching the user's mouth. The aerosol-forming substrate may be provided as part of an aerosol-forming article. The aerosol-forming article may have a strip shape for inserting the aerosol-generating article into a cavity of an aerosol-generating device. A tubular heater may be arranged around the cavity to heat the aerosol-forming substrate once the aerosol-forming article has been inserted into the cavity of the aerosol-generating device. The tubular heater may comprise a resistive heating element or an inductive heating element, such as a susceptor.

Disclosure of Invention

It is desirable to provide a tubular heater for an aerosol-generating device that is robust and easy to manufacture.

In accordance with the present disclosure, a method of forming a tubular heater for an aerosol-generating system is provided. The method may include providing a heat pipe. The method may further comprise providing a flexible heating element. The method may further include at least partially defining a heat pipe with the flexible heating element. The method may further include clamping the flexible heating element to the heat pipe with a clamping clamp. The method may further include heating the heat pipe, the flexible heating element, and the clamping fixture.

Advantageously, heating the heat pipe and the flexible heating element may secure the flexible heating element to the heat pipe while the heat pipe and the flexible heating element are clamped together by the clamping fixture. In some preferred embodiments, heating the heat pipe and the flexible heating element while the heat pipe and the flexible heating element are held together by a holding fixture may secure the flexible heating element to the heat pipe by thermal compression. In a preferred embodiment, an adhesive is disposed between the heat pipe and the flexible heating element, and heating the heat pipe and the flexible heating element while the heat pipe and the flexible heating element are held together by the holding fixture activates the adhesive to secure the flexible heating element to the heat pipe.

Advantageously, the tubular heater formed by this method is compact and efficient because the flexible heating element is in close proximity to the heat pipe. Advantageously, the tubular heater formed by this method is robust because the flexible heating element is firmly bonded to the heat conducting tube. Advantageously, the tubular heater formed by this method facilitates uniform heating of the aerosol-forming substrate received in the tubular heater because the heat-conducting tube evenly distributes heat from the flexible heater around the aerosol-forming substrate received in the tubular heater.

The tubular heater includes a heat pipe. The heat pipe may be formed of any suitable heat conductive material. As used herein, the term "thermally conductive" refers to a material having a bulk thermal conductivity greater than about 10 watts per meter kelvin (W/(m·k)) at 23 degrees celsius and 50% relative humidity as measured using the Modified Transient Planar Source (MTPS) method. Preferably, the heat conducting tube comprises a metal. In some preferred embodiments, the heat pipe comprises stainless steel, such as SAE 304.

The heat pipe may be open at one end to receive the aerosol-forming substrate. Preferably, the heat transfer tube is open at both ends. The heat pipe may have any suitable cross-sectional shape. For example, the heat pipe may have a circular, oval, triangular, or rectangular cross-sectional shape. Preferably, the heat conductive pipe has a circular cross-sectional shape. Preferably, the heat conducting tube is dimensioned to receive an aerosol-forming substrate, such as an end of a strip-shaped aerosol-generating article. The heat pipe may have any suitable thickness. For example, the heat pipe may have a thickness of between about 50 microns and about 200 millimeters, and preferably has a thickness of about 100 microns.

The tubular heater further comprises a flexible heating element. As used herein, the term "flexible" is used to mean that the heating element can be bent or rolled at 23 degrees celsius to substantially conform to the shape of the tubular heating element. For example, the flexible heating element may be rolled into a tube.

The flexible heating element at least partially defines a heat pipe. In some preferred embodiments, the flexible heating element defines a heat pipe. The heat pipe and the flexible heating element may form a coaxially aligned pipe. The heat pipe may be received inside the flexible heating element when the flexible heating element is rolled into a tube.

In some preferred embodiments, the flexible heating element comprises an electrically insulating substrate. As used herein, the term "electrically insulating" refers to a material having a volume resistivity of greater than about 1x 10-6 ohm-meters (Ω -m) at 20 degrees Celsius (DEG C), typically between about 1x 10-9 ohm-meters (Ω -m) and about 1x 10-21 ohm-meters (Ω -m).

The electrically insulating substrate may be formed of any suitable electrically insulating material. The electrically insulating substrate may be formed of any suitable material capable of withstanding high temperatures, for example, temperatures in the range between 150 degrees celsius and 250 degrees celsius, or in the range between 250 degrees celsius and 350 degrees celsius. The electrically insulating material may be a dielectric material. The electrically insulating substrate may comprise a polymer. In some preferred embodiments, the electrically insulating substrate comprises polyimide. The electrically insulating substrate may be composed of polyimide. The electrically insulating substrate may comprise a polyimide film, for example

Preferably, the electrically insulating substrate is flexible. The flexible electrically insulating substrate may be bent or rolled at 23 degrees celsius to substantially conform to the shape of the tubular heating element.

Preferably, the electrically insulating substrate is thermally insulating. As used herein, the term "thermally insulating" refers to a material having a bulk thermal conductivity of less than about 6 watts per meter kelvin (W/(m·k)) at 23 degrees celsius and 50% relative humidity as measured using the Modified Transient Planar Source (MTPS) method.

The electrically insulating substrate may have any suitable thickness. For example, the electrically insulating substrate may have a thickness of between about 15 microns and 50 microns, or between about 20 microns and about 30 microns. Preferably, the electrically insulating substrate has a thickness of about 25 microns.

In some preferred embodiments, the flexible heating element comprises a conductive track. As used herein, the term "conductive" refers to a material having a volume resistivity of less than about 1x 10-5 ohm-meters (Ω -m) at 20 ℃, typically between about 1x 10-5 ohm-meters (Ω -m) and about 1x 10-9 ohm-meters (Ω -m).

The conductive tracks may be formed of any suitable conductive material. For example, the conductive tracks may comprise at least one of copper, gold, platinum, and stainless steel (e.g., SAE 304). The conductive track may comprise conductive ink. Where the conductive tracks comprise conductive ink, the conductive tracks may be printed on an electrically insulating substrate. Suitable conductive inks may include silver to provide conductivity.

In some preferred embodiments, the electrically insulating substrate comprises a first electrically insulating substrate and a second electrically insulating substrate. In these preferred embodiments, the conductive track may be arranged between the first electrically insulating substrate and the second electrically insulating substrate.

The conductive tracks may form resistive heating tracks. The resistive heating track may act as a resistive heater.

In some embodiments, the conductive rail comprises a single rail. In other embodiments, the conductor rail comprises at least two conductor rails.

The conductive tracks may have any suitable thickness. For example, the conductive tracks may have a thickness between about 20 microns and about 60 microns or between about 30 microns and about 50 microns. Preferably, the conductive tracks have a thickness of about 40 microns.

In some embodiments, the clamped heat pipe and flexible heating element may be heated to a temperature sufficient to directly bond the heat pipe and flexible heating element. This bond may be due to the simultaneous application of pressure and heat, thereby creating a thermo-compression bond.

In some preferred embodiments, an adhesive is disposed between the heat pipe and the flexible heating element. Heating the heat pipe and the flexible heating element while they are held together by the holding fixture may activate the adhesive. Any suitable adhesive may be used. The adhesive may be any suitable adhesive that is capable of withstanding high temperatures once cured, for example, temperatures in the range of between 150 degrees celsius and 250 degrees celsius, or in the range of between 250 degrees celsius and 350 degrees celsius. The adhesive may be a thermosetting adhesive. As used herein, a thermoset adhesive is an adhesive that irreversibly hardens after the application of heat and pressure. The adhesive may include an epoxy resin. The binder may include an acrylic resin. The adhesive may comprise polyimide.

The adhesive may have any suitable thickness. For example, the adhesive may have a thickness of between about 3 microns and about 10 microns. Preferably, the adhesive has a thickness of about 5 microns.

In some embodiments, an adhesive may be applied to the heat pipe. In some embodiments, an adhesive may be applied to the flexible heating element.

In some preferred embodiments, wherein the flexible heating element comprises an electrically insulating substrate comprising a first electrically insulating substrate, a second electrically insulating substrate, and a conductive track disposed between the first electrically insulating substrate and the second electrically insulating substrate, an adhesive may be disposed between the first electrically insulating substrate and the second electrically insulating substrate. The adhesive may be any suitable adhesive that is capable of withstanding high temperatures once cured, for example, temperatures in the range of between 150 degrees celsius and 250 degrees celsius, or in the range of between 250 degrees celsius and 350 degrees celsius. The adhesive may be a thermosetting adhesive. The adhesive may include an epoxy resin. The binder may include an acrylic resin. The adhesive may comprise polyimide.

The adhesive may have any suitable thickness. For example, the adhesive may have a thickness of between about 3 microns and about 10 microns. Preferably, the adhesive has a thickness of about 5 microns.

In some embodiments, the adhesive between the heat pipe and the flexible heating element may be the same as the adhesive between the first electrically insulating substrate and the second electrically insulating substrate. In some embodiments, the adhesive between the heat pipe and the flexible heating element may be different than the adhesive between the first electrically insulating substrate and the second electrically insulating substrate.

The heat pipe, flexible heating element and optional adhesive are held together by a holding clamp. In some embodiments, the clamping force is no greater than 50 newtons, 100 newtons, 150 newtons, 200 newtons, or 250 newtons. Preferably, the clamping force is no greater than 200 newtons. Advantageously, limiting the clamping force reduces the likelihood of clamping damage to the heat pipe. Advantageously, limiting the clamping force may reduce the likelihood of pressing adhesive out from between the heat pipe and the flexible heating element during clamping.

Preferably, the clamping fixture is configured to provide a uniform clamping force around the surface of the heat pipe and the flexible heating element.

Preferably, the clamping fixture comprises a non-stick coating. The clamping fixture may include a friction reducing coating. For example, the clamping fixture may include a Polytetrafluoroethylene (PTFE) coating. Providing a non-stick coating or friction reducing coating on the clamping fixture may reduce the likelihood of damage to the flexible heating element during heating.

The method includes heating the held heat pipe and the flexible heating element. The heating may be performed at any suitable temperature and for any suitable duration to enable the flexible heating element to be coupled with the heat pipe.

In some embodiments, the clamped heat pipe and the flexible heating element may be heated at a temperature of at least 250 degrees celsius, at least 300 degrees celsius, or at least 360 degrees celsius. In some embodiments, the clamped heat pipe and the flexible heating element may be heated at a temperature between about 250 degrees celsius and about 400 degrees celsius. In some embodiments, the clamped heat pipe and the flexible heating element may be heated at a temperature within 380 degrees celsius or 380 degrees celsius ± five degrees celsius.

In some embodiments, the clamped heat pipe and the flexible heating element may be heated at a temperature of at least 250 degrees celsius, at least 300 degrees celsius, or at least 360 degrees celsius for at least 5 minutes. In some embodiments, the clamped heat pipe and the flexible heating element may be heated at a temperature between about 250 degrees celsius and about 400 degrees celsius for about 5 minutes to about 20 minutes. In some embodiments, the clamped heat pipe and flexible heating element may be heated at a temperature within 380 degrees celsius or 380 degrees celsius ± five degrees celsius for 10 to 15 minutes.

After heating, the clamped heat pipe and flexible heating element may be cooled before removing the clamping fixture. The clamped heat pipe and flexible heating element may be cooled at any suitable temperature and for any suitable duration.

In some embodiments, after heating the clamped heat pipe and the flexible heating element, the clamped heat pipe and the flexible heating element are cooled at room temperature.

In some preferred embodiments, the clamped heat pipe and the flexible heating element are cooled at a temperature of at least about 160 degrees celsius. In some preferred embodiments, the clamped heat pipe and the flexible heating element are cooled at a temperature between about 160 degrees celsius and about 240 degrees celsius. In some preferred embodiments, the clamped heat pipe and the flexible heating element are cooled at a temperature within 200 degrees celsius or 200 degrees celsius ± five degrees celsius.

In some preferred embodiments, the clamped heat pipe and flexible heating element are cooled at a temperature of at least about 160 degrees celsius for at least 1 minute. In some preferred embodiments, the clamped heat pipe and flexible heating element are cooled at a temperature between about 160 degrees celsius and about 240 degrees celsius for about 1 minute to about 5 minutes. In some preferred embodiments, the clamped heat pipe and flexible heating element are cooled at a temperature within 200 degrees celsius or 200 degrees celsius ± five degrees celsius for about 3 minutes.

After heating the clamped heat pipe and flexible heating element, the clamping fixture may be removed from the heat pipe and flexible heating element and a temperature sensor provided. The method may comprise, after heating the clamped heat pipe and the flexible heating element: removing the clamping fixture from the heat pipe and flexible heating element; providing a temperature sensor; positioning the temperature sensor on one of the heat pipe and the flexible heating element with a positioning fixture; and securing the temperature sensor to at least one of the heat pipe and the flexible heating element. Advantageously, providing a temperature sensor on the heat pipe or the flexible heating element may enable the tubular heater to provide accurate feedback of the temperature of the tubular heater to the aerosol-generating device during use.

The temperature sensor may be secured to at least one of the heat pipe and the flexible heating element by any suitable means. In some preferred embodiments, the temperature sensor is welded to at least one of the heat pipe and the flexible heating element. In some particularly preferred embodiments, the temperature sensor is welded to at least one of the heat pipe and the flexible heating element by resistance welding.

The temperature sensor may be any suitable temperature sensor capable of withstanding high temperatures, for example, in the range of 150 degrees celsius to 250 degrees celsius, or in the range of 250 degrees celsius to 350 degrees celsius. In some preferred embodiments, the temperature sensor is a resistance thermometer. In some particularly preferred embodiments, the temperature sensor is a platinum resistance temperature detector, such as PT100 or PT1000.

In some embodiments, a conductive track is provided for electrically connecting to a temperature sensor. In some preferred embodiments, a conductive track is provided on the flexible heating element to electrically connect to the temperature sensor.

Where the flexible heating element comprises an electrically insulating substrate and a conductive track, the flexible heating element may comprise a first conductive track and a second conductive track. The first electrically conductive track may be disposed on a first side of the electrically insulating substrate and the second electrically conductive track may be disposed on a second side of the electrically insulating substrate opposite the first side. The first conductive track may act as a resistive heating element and the second conductive track may be electrically connected to a temperature sensor.

In the case where the flexible heating element comprises a first electrically insulating substrate, a second electrically insulating substrate, and a conductive track arranged between the first electrically insulating substrate and the second electrically insulating substrate, the conductive track arranged between the first electrically insulating substrate and the second electrically insulating substrate may be the first conductive track, and the flexible heater may comprise the second conductive track arranged on an outer surface of the second electrically insulating substrate. The first conductive track may act as a resistive heating element and the second conductive track may be electrically connected to a temperature sensor.

In some embodiments, an electrically insulating substrate may be disposed at least partially over the conductive tracks to electrically connect to the temperature sensor. Advantageously, positioning the electrically insulating substrate at least partially over the electrically conductive track for electrical connection to the temperature sensor may help to protect the electrically conductive track from damage during heating of the clamped heat pipe and flexible heating element.

The electrically insulating substrate, which is at least partially disposed over the conductor rails to be electrically connected to the temperature sensor, may be formed of any suitable electrically insulating material. The electrically insulating substrate may be formed of any suitable material capable of withstanding high temperatures, for example, temperatures in the range between 150 degrees celsius and 250 degrees celsius, or in the range between 250 degrees celsius and 350 degrees celsius. The electrically insulating material may be a dielectric material. The electrically insulating substrate may comprise a polymer. In some preferred embodiments, the electrically insulating substrate comprises polyimide. The electrically insulating substrate may be composed of polyimide. The electrically insulating substrate may comprise a polyimide film, for example

Preferably, the electrically insulating substrate is thermally insulating. As used herein, the term "thermally insulating" refers to a material having a bulk thermal conductivity of less than about 6 watts per meter kelvin (W/(m·k)) at 23 degrees celsius and 50% relative humidity as measured using the Modified Transient Planar Source (MTPS) method.

The electrically insulating substrate may have any suitable thickness. For example, the electrically insulating substrate may have a thickness of between about 15 microns and 50 microns, or between about 20 microns and about 30 microns. Preferably, the electrically insulating substrate has a thickness of about 25 microns.

In some embodiments, an adhesive may be disposed between the conductive track for electrically connecting to the temperature sensor and an electrically insulating substrate disposed at least partially over the conductive track for electrically connecting to the temperature sensor. The adhesive may be any suitable adhesive that is capable of withstanding high temperatures once cured, for example, temperatures in the range of between 150 degrees celsius and 250 degrees celsius, or in the range of between 250 degrees celsius and 350 degrees celsius. The adhesive may be a thermosetting adhesive. The adhesive may include an epoxy resin. The binder may include an acrylic resin. The adhesive may comprise polyimide.

The adhesive may have any suitable thickness. For example, the adhesive may have a thickness of between about 3 microns and about 10 microns. Preferably, the adhesive has a thickness of about 5 microns.

In some embodiments, the adhesive between the conductive track for electrically connecting to the temperature sensor and the electrically insulating substrate disposed at least partially over the conductive track for electrically connecting to the temperature sensor may be the same as the adhesive between the first electrically insulating substrate and the second electrically insulating substrate. In some embodiments, the adhesive between the conductive track for electrically connecting to the temperature sensor and the electrically insulating substrate disposed at least partially over the conductive track for electrically connecting to the temperature sensor may be different from the adhesive between the first electrically insulating substrate and the second electrically insulating substrate.

In some embodiments, the flexible heating element may include one or more electrical contacts. The electrical contacts may be arranged at the periphery of the flexible heating element. The electrical contacts may extend away from the heat pipe. The electrical contacts may provide points of contact for the wires to electrically connect the tubular heater to other electrical components of the aerosol-generating device. In these embodiments, the method may further comprise: providing one or more wires; positioning one or more wires over each of one or more electrical contacts of the flexible heating element; and securing the one or more wires to one or more electrical contacts of the flexible heating element.

The one or more wires may be secured to one or more electrical contacts of the flexible heating element by welding. In particular, the one or more wires may be secured to one or more electrical contacts of the flexible heating element by resistance welding or laser welding.

In the method of forming the tubular heater, the one or more wires may be secured to one or more contact points of the flexible heating element at any suitable point. For example, one or more wires may be secured to one or more contact points prior to securing the temperature sensor to at least one of the heat pipe and the flexible heating element. In a preferred embodiment, the one or more wires are secured to the one or more contact points of the flexible heating element after the temperature sensor is secured to at least one of the heat pipe and the flexible heating element.

After securing the temperature sensor to at least one of the heat pipe and the flexible heating element, the method may further comprise: providing a heat-shrinkable sleeve configured to decrease in size when heated; inserting the heat pipe, the flexible heating element and the temperature sensor into the heat-shrinkable sleeve; a heating heat pipe, a flexible heating element, a temperature sensor and a heat shrinkable sleeve.

The heat-shrinkable sleeve may be formed of any suitable material that enables the sleeve to decrease in size when heated. In some embodiments, the heat-shrinkable sleeve comprises a polymer. In some particularly preferred embodiments, the heat-shrinkable sleeve comprises Polyetheretherketone (PEEK).

Preferably, the heat-shrinkable sleeve is heated to a suitable temperature for a suitable duration to reduce the size of the heat-shrinkable sleeve. Providing a heat-shrinkable sleeve over the heat pipe, the flexible heating element, and the temperature sensor and heating such that the heat-shrinkable sleeve is reduced in size may cause the heat-shrinkable sleeve to compress the temperature sensor against at least one of the heat pipe and the flexible heating element. Advantageously, this may improve the accuracy of the temperature reading from the temperature sensor and ensure that the temperature sensor is held firmly against at least one of the heat pipe and the flexible heating element.

In some preferred embodiments, the heat pipe, flexible heating element, temperature sensor, and heat shrinkable sleeve are heated at a temperature of at least 300 degrees celsius. In some preferred embodiments, the heat pipe, flexible heating element, temperature sensor, and heat shrinkable sleeve are heated at a temperature between about 300 degrees celsius and 400 degrees celsius, and at a temperature within 340 degrees celsius or 340 degrees celsius ± 5 degrees celsius.

In some preferred embodiments, the heat pipe, flexible heating element, temperature sensor, and heat shrinkable sleeve are heated at a temperature of at least 300 degrees celsius for at least 5 seconds. In some preferred embodiments, the heat pipe, flexible heating element, temperature sensor, and heat shrinkable sleeve are heated at a temperature between about 300 degrees celsius and 400 degrees celsius for about 5 seconds to about 15 seconds. In some preferred embodiments, the heat pipe, flexible heating element, temperature sensor, and heat shrinkable sleeve are heated at a temperature within 340 degrees celsius or 340 degrees celsius ± 5 degrees celsius for 8 seconds to 10 seconds.

According to the present disclosure, there is also provided a tubular heater formed by the above method.

In a particularly preferred embodiment, a tubular heater according to the present disclosure comprises: a heat conduction pipe; a flexible heating element at least partially defining a heat pipe; a temperature sensor secured to at least one of the heat pipe and the flexible heating element; and a heat shrinkable tube defining a heat pipe, a flexible heating element, and a temperature sensor.

Drawings

Examples in accordance with aspects of the present disclosure will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic cross-sectional view showing the interior of an aerosol-generating device 100 and an aerosol-generating article 200 received within the aerosol-generating device 100;

FIG. 2 is a schematic exploded view of a tubular heater according to the present disclosure for use in the system shown in FIG. 1;

FIG. 3 is a side view of the tubular heater of FIG. 2;

FIG. 4 is a cross-sectional view showing the inner layers of the tubular heater of FIG. 1;

FIG. 5 is a diagrammatic representation of the inner layers of the tubular heater of FIG. 1;

FIG. 6 is a diagrammatic representation of the inner layers of an alternative tubular heater according to the present disclosure;

FIG. 7 is a diagrammatic representation of the inner layers of an alternative tubular heater according to the present disclosure;

FIG. 8 is a schematic view of a clamping fixture in an open position for use in a method according to the present disclosure; and

Fig. 9 is a schematic view of the clamping fixture of fig. 8 in a closed position.

Detailed Description

Fig. 1 is a schematic cross-sectional view showing the interior of an aerosol-generating device 100 and an aerosol-generating article 200 received within the aerosol-generating device 100. The aerosol-generating device 100 and the aerosol-generating article 200 together form an aerosol-generating system. In fig. 1, an aerosol-generating device 100 is shown in a simplified manner. In particular, the elements of the aerosol-generating device 100 are not drawn to scale. Furthermore, elements not relevant for understanding the aerosol-generating device 100 are omitted.

The aerosol-generating device 100 comprises a housing 102 housing the tubular heater 6, the power supply 103 and the control circuit 105. In fig. 1, a bottom heater housing portion 2, a heater mount 8 and a top heater housing portion 4 are shown. The power source 103 is a battery, and in this example, is a rechargeable lithium ion battery. The control circuit 105 is connected to both the power supply 103 and the heating element and controls the supply of electrical energy from the power supply 103 to the heater to regulate the temperature of the heater.

The housing 102 comprises an opening 104 at a proximal or mouth end of the aerosol-generating device 100 through which the aerosol-generating article 200 is received. The opening 104 is connected to an opening 12 in the heater module 1 through which aerosol exits the heater module 1. However, it should be appreciated that the aerosol leaves the heater module 1 and the aerosol-generating device 100 for the most part via the aerosol-generating article 200. The housing 102 further comprises an air inlet 106 at the distal end of the aerosol-generating device 100. The air inlet 106 is connected to an air inlet arranged at the distal end of the first tubular section 2b of the bottom housing part 2. The first tubular section 2b delivers air from the air inlet 106 to the aerosol-generating article.

The aerosol-generating article 200 comprises an end plug 202, an aerosol-forming substrate 204, a hollow tube 206 and a mouthpiece filter 208. Each of the above-described components of the aerosol-generating article 100 is a substantially cylindrical element, each having substantially the same diameter. The components are arranged in sequence in contiguous coaxial alignment and are defined by an outer wrapper 210 to form a cylindrical bar. The aerosol-forming substrate 204 is a tobacco rod or rod comprising an aggregated sheet of crimped homogenized tobacco material defined by a wrapper (not shown). The crimped sheet of homogenized tobacco material comprises glycerin as an aerosol former. The end plug 202 and mouthpiece filter 208 are formed from cellulose acetate fibers.

The distal end of the aerosol-generating article 200 is inserted into the aerosol-generating device 100 via the opening 104 in the housing 102 and pushed into the aerosol-generating device 100 until it engages a stop (not shown in fig. 1) arranged on the heater mount 8, at which point the aerosol-generating article is fully inserted. The stop aids in properly positioning the aerosol-forming substrate 204 within the heater so that the heater can heat the aerosol-forming substrate 204 to form an aerosol.

The aerosol-generating device 100 may further comprise: a sensor (not shown) for detecting the presence of the aerosol-generating article 200; a user interface (not shown), such as a button, for activating the heater; and a display or indicator (not shown) for presenting information to the user (e.g., remaining battery power, heating status, and error message).

In use, as shown in fig. 1, a user inserts an aerosol-generating article 200 into the aerosol-generating device 100. The user then begins the heating cycle by activating the aerosol-generating device 100 (e.g., by pressing a switch to turn the device on). In response, the control circuit 105 controls the supply of power from the power supply 103 to the heater to heat the heater. During the heating cycle, the heater is heated to a predetermined temperature or a predetermined temperature range according to the temperature profile. The heating cycle may last for about 6 minutes. Heat from the heater 6 is transferred to the aerosol-forming substrate 204, which releases volatile compounds from the aerosol-forming substrate 204. The volatile compounds form an aerosol within an aerosolization chamber formed by the hollow tube 206. During the heating cycle, the user places the mouthpiece filter 208 of the aerosol-generating article 200 between the lips of its mouth and draws or inhales on the mouthpiece filter 208. The generated aerosol is then drawn into the mouth of the user through the mouthpiece filter 102.

Fig. 2 shows an exploded view of a tubular heater 6 suitable for use in the aerosol-generating device 100 of fig. 1. The tubular heater 6 comprises a heat conducting tube 61 having a circular cross section and two open ends. The heat pipe 61 is formed of a SAE 304 stainless steel sheet 100 μm thick. The tubular heater 6 further comprises a flexible heating element 62 comprising a serpentine conductor rail 63 arranged between a first electrically insulating substrate 64 and a second electrically insulating substrate 64. The conductor rail 63 is formed from SAE 304 stainless steel 40 microns thick. The first electrically insulating substrate 64 and the second electrically insulating substrate 65 are made of polyimide having a thickness of 25 μmFilm formation. Another disconnected conductor rail 66 is provided on the outer surface of the second electrically insulating substrate 65 on the side opposite to the conductor rail 63. Another disconnected conductor rail 66 is used to electrically connect a temperature sensor 67, which in this embodiment is a PT1000 platinum resistance detector. Four electrical contacts 68 extend from the flexible heating element 62 to electrically connect the tubular heater to other electrical components of the aerosol-generating device. Two of the electrical contacts 68 are electrically connected to the conductive tracks 66 to power the flexible heating element 62. The other two electrical contacts 68 are connected to opposite ends of the broken conductor rail 66 to be electrically connected to the temperature sensor 67. The tubular heater also includes a heat-shrinkable sleeve 69 fitted over the heat-conducting tube 61 and the flexible heater 62. The heat-shrinkable sleeve 69 reduces in size when heated and compresses the temperature sensor 67 against the second electrically insulating substrate 65 of the flexible heating element 62 to ensure that the temperature sensor 67 remains tightly against the flexible heating element 62 and is held in a secure manner that is unlikely to be dislodged during normal use. In this embodiment, the heat shrinkable sleeve is formed from PEEK and is configured to decrease in diameter from about 10 millimeters prior to heating to about 8.5 millimeters after heating.

An adhesive layer (not shown in fig. 2) is provided between the heat conductive pipe 61 and the first electrically insulating substrate 64. In this embodiment, the adhesive is a thermosetting adhesive that requires heat and pressure to form a strong bond.

Another adhesive layer (also not shown in fig. 2) is provided between the conductive tracks 63 and the second electrically insulating substrate 65. In this embodiment, the two adhesive layers are formed of the same adhesive and have a thickness of about 5 microns. It should be appreciated that in other embodiments, different adhesives may be used.

Fig. 3 shows the tubular heater 6 of fig. 2 in assembled form ready for connection to an aerosol-generating device.

Fig. 4 shows a cross-sectional view of the tubular heater of fig. 1 taken through the temperature sensor 68, showing the inner layers forming the tubular heater 6. Fig. 5 shows a diagrammatic representation of the inner layers of the tubular heater of fig. 1. As shown in fig. 4 and 5, the tubular heater 6 of fig. 2 and 3 starts from the inner layer and moves towards the outer layer comprises the following layers: a heat pipe 61, an adhesive layer 70, a first electrically insulating substrate 64, a conductive track 63, a further adhesive layer 70, a second electrically insulating substrate 65, a temperature sensor 67 and a disconnected conductive track 66, and a heat-shrinkable sleeve 69.

Fig. 6 shows a diagrammatic representation of the inner layers of the alternative tubular heater shown in fig. 2 to 5. The tubular heater 6 of fig. 6 is substantially similar to the tubular heater 6 of fig. 2-5, and like reference numerals refer to like features. The only difference between the tubular heater 6 of fig. 6 compared to the tubular heater 6 of fig. 2-5 is that the tubular heater 6 of fig. 6 comprises an additional adhesive layer 70 between the second electrically insulating substrate 64 and the disconnected electrically conductive tracks 66.

Fig. 7 shows a diagrammatic representation of the alternative tubular heater shown in fig. 2 to 5 and the inner layers of the tubular heater 6 of fig. 6. The tubular heater 6 of fig. 7 is substantially similar to the tubular heater 6 of fig. 2-5 and the tubular heater 6 of fig. 6, and like reference numerals refer to like features. The only difference between the tubular heater 6 of fig. 7 compared to the tubular heater 6 of fig. 6 is that the tubular heater 6 of fig. 7 comprises a third electrically insulating substrate 71 above the broken conductor rails 66 and the third electrically insulating substrate comprises apertures or holes for receiving the temperature sensors 67.

The tubular heater 6 described above with reference to fig. 2 to 5 is formed by the following method:

1. Providing a heat conductive pipe 61;

2. Providing a flexible heating element 62;

3. The heat pipe 61 is fully defined by a flexible heating element 62;

4. clamping the flexible heating element 62 to the heat conductive pipe 61 with a clamping jig 300 as shown in fig. 8 and 9;

5. heating the clamped heat pipe 61 and the flexible heating element 62 in a tunnel oven at a temperature of 380 degrees celsius (±5 degrees celsius) for 12 minutes, wherein the conveyor is configured to move the clamped heat pipe 61 and the flexible heating element 62 from one end of the tunnel oven to the other;

6. Cooling the clamped heat pipe 61 and the flexible heating element 62 in another tunnel oven at a temperature of 200 degrees celsius (±5 degrees celsius) for about 3 minutes, wherein the conveyor is configured to move the clamped heat pipe 61 and the flexible heating element 62 from one end of the tunnel oven to the other;

7. Cooling the clamped heat pipe 61 and flexible heating element 62 to room temperature (about 23 degrees celsius);

8. removing the heat pipe 61 and the flexible heating element 62 from the clamping jig 300;

9. The heat pipe 61 and flexible heating element 62 are inspected and the resistance of the conductive track 63 is tested, which in this embodiment should be about 1 ohm (+ -2%);

10. providing a temperature sensor 67;

11. Positioning the temperature sensor 67 on the flexible heating element 62 with a positioning fixture (not shown) and aligning the disconnected conductor rail 66 with the temperature sensor 67 such that the temperature sensor 67 is electrically connected to the disconnected conductor rail 66;

12. fixing the temperature sensor 67 to the flexible heating element 62 by resistance welding or laser welding;

13. Removing the heat pipe 61, the flexible heating element 62 and the temperature sensor 67 from the positioning jig;

14. testing the resistance of the temperature sensor 67;

15. providing one or more wires;

16. Positioning one or more wires (not shown) over each of the one or more electrical contacts 68 of the flexible heating element 62 with another positioning fixture;

17. One or more wires are secured to one or more electrical contacts 68 of the flexible heating element 62 by resistance welding or laser welding;

18. Removing the heat pipe 61, the flexible heating element 62, the temperature sensor 67 and the wires from the localization fixture;

19. Inspecting the heat pipe 61, the flexible heating element 62, the temperature sensor 67 and the wires;

20. Providing a heat shrinkable sleeve 69;

21. Inserting the heat pipe 61, the flexible heating element 62 and the temperature sensor 67 into the heat-shrinkable sleeve 69;

22. Heating the heat pipe 61, the flexible heating element 62, the temperature sensor 67 and the heat shrinkable sleeve 69 at a temperature of 340 degrees celsius (±5 degrees celsius) for 8 seconds to 10 seconds; and

23. The completed tubular heater 6 is inspected.

It should be appreciated that some steps in this method are not necessary to form the tubular heater 6, and that some additional or alternative steps may be required to provide a tubular heater according to various embodiments of the present disclosure. It should also be appreciated that some of the steps in this method may be performed in a different order or simultaneously. For example, in some embodiments, some inspection steps may be combined.

Regarding the step of clamping the flexible heating element 62 to the heat conductive pipe 61 with the clamping jig 300 (as shown in fig. 8 and 9), the clamping jig 300 includes a main shaft 301 on which the heat conductive pipe 61 is received and a pair of clamps 302, 303. The clamps 302, 303 may be arranged together in a closed position, as shown in fig. 9, in which the clamps 302, 303 define a cavity of complementary shape to the heat pipe 61 but slightly larger diameter. Each clamp 302, 303 defines half of a cavity. As shown in fig. 8, the jaws 302, 303 may be separated from each other to an open position. In the open position, the flexible heating element 62 may be disposed across half of the cavity defined by the clamp 301. The spindle 301 and heat pipe 61 may then be pressed into one half of the cavity defined by the clamp 301, deforming a portion of the flexible heating element 62 around a portion of the heat pipe 61. The remainder of the flexible heating element 62 may then be bent around the remainder of the heat pipe 61 and the clamp 302 placed over the clamp 303 to move the clamping clamp 300 to the closed position and clamp the flexible heating element 62 to the heat pipe 61. The clamps 302, 303 may be secured in the closed position by various means including torque screws that may be used to vary the clamping force on the flexible heating element 62 against the heat pipe 61. The clamping force on the flexible heating element 62 to the heat pipe 61 is maintained at 200 newtons or less to reduce the likelihood of clamping damage to the heat pipe.

For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing quantities, amounts, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Additionally, all ranges include the disclosed maximum and minimum points, and include any intervening ranges therein, which may or may not be specifically enumerated herein. Thus, in this context, the number a is understood to be a±5 percent (5%) a. In this context, the number a may be considered to include values within a general standard error for the measurement of the property of the modification of the number a. In some cases, as used in the appended claims, the number a may deviate from the percentages recited above, provided that the amount of deviation a does not materially affect the basic and novel characteristics of the claimed invention. Additionally, all ranges include the disclosed maximum and minimum points, and include any intervening ranges therein, which may or may not be specifically enumerated herein.

Claims (40)

1. A method of forming a tubular heater for an aerosol-generating system, the method comprising:

providing a heat conducting pipe;

providing a flexible heating element;

At least partially defining the heat pipe with the flexible heating element;

Clamping the flexible heating element to the heat pipe with a clamping clamp; and

Heating the clamped heat pipe and the flexible heating element.

2. The method of claim 1, wherein the flexible heating element comprises an electrically insulating substrate and a conductive track.

3. The method of claim 2, wherein the electrically insulating substrate comprises a first electrically insulating substrate and a second electrically insulating substrate, and wherein the conductive track is disposed between the first electrically insulating substrate and the second electrically insulating substrate.

4. A method according to claim 2 or claim 3, wherein the electrically insulating substrate comprises a polymer and optionally the electrically insulating substrate comprises polyimide.

5. The method of any of claims 1-4, further comprising providing an adhesive between the heat pipe and the flexible heating element.

6. The method of claim 5, wherein the method further comprises applying the adhesive to the heat pipe.

7. The method of claim 5, wherein the method further comprises applying the adhesive to the flexible heating element.

8. The method according to any one of claims 1 to 7, wherein the heat conducting tube comprises stainless steel, such as SAE 304.

9. The method of any of claims 1-8, wherein the clamping comprises clamping the flexible heating element to the heat pipe with a force of no more than 200 newtons.

10. The method of any one of claims 1 to 9, wherein the clamping fixture comprises a Polytetrafluoroethylene (PTFE) coating.

11. The method of any of claims 1-10, wherein the heating comprises heating the clamped heat pipe and flexible heating element at a temperature of at least 360 degrees celsius.

12. The method of any one of claims 1 to 11, wherein the heating comprises heating the clamped heat pipe and flexible heating element at a temperature between about 360 degrees celsius and about 400 degrees celsius.

13. The method of any one of claims 1 to 12, wherein the heating comprises heating the clamped heat pipe and flexible heating element at a temperature within 380 degrees celsius or 380 degrees celsius ± five degrees celsius.

14. The method of any one of claims 1 to 13, wherein the heating comprises heating the clamped heat pipe and flexible heating element at a temperature of at least 360 degrees celsius for at least 5 minutes.

15. The method of any one of claims 1 to 14, wherein the heating comprises heating the clamped heat pipe and flexible heating element at a temperature between about 360 degrees celsius and about 400 degrees celsius for about 5 minutes to about 20 minutes.

16. The method of any one of claims 1 to 15, wherein the heating comprises heating the clamped heat pipe and flexible heating element at a temperature within 380 degrees celsius or 380 degrees celsius ± five degrees celsius for 10 to 15 minutes.

17. The method of any one of claims 1 to 16, further comprising cooling the clamped heat pipe and flexible heating element after heating the clamped heat pipe and flexible heating element.

18. The method of claim 17, wherein the cooling comprises cooling the clamped heat pipe and flexible heating element at a temperature of at least about 160 degrees celsius.

19. The method of claim 17 or claim 18, wherein the cooling comprises cooling the clamped heat pipe and flexible heating element at a temperature between about 160 degrees celsius and about 240 degrees celsius.

20. The method of any of claims 17 to 19, wherein the cooling comprises cooling the clamped heat pipe and flexible heating element at a temperature within 200 degrees celsius or 200 degrees celsius ± five degrees celsius.

21. The method of any one of claims 17 to 20, wherein the cooling comprises cooling the clamped thermally conductive tube and flexible heating element at a temperature of at least about 160 degrees celsius for at least 1 minute.

22. The method of claim 17 or claim 21, wherein the cooling comprises cooling the clamped heat pipe and flexible heating element at a temperature between about 160 degrees celsius and about 240 degrees celsius for about 1 minute to about 5 minutes.

23. The method of any one of claims 17 to 22, wherein the cooling comprises cooling the clamped heat pipe and flexible heating element at a temperature within 200 degrees celsius or 200 degrees celsius ± five degrees celsius for about 3 minutes.

24. The method of any of claims 1 to 23, further comprising, after heating the clamped heat pipe and flexible heating element:

Removing the clamping fixture from the heat pipe and flexible heating element;

Providing a temperature sensor;

Positioning the temperature sensor on one of the heat pipe and the flexible heating element with a positioning fixture; and

The temperature sensor is secured to at least one of the heat pipe and the flexible heating element.

25. The method of claim 24, wherein the securing comprises welding the temperature sensor to at least one of the heat pipe and the flexible heating element.

26. The method of claim 25, wherein the securing comprises resistance welding or laser welding the temperature sensor to at least one of the heat pipe and the flexible heating element.

27. The method of any one of claims 24 to 26, wherein the temperature sensor is a resistance thermometer.

28. The method of any one of claims 24 to 27, wherein:

The flexible heating element includes one or more electrical contacts; and

The method further includes, after securing the temperature sensor to at least one of the heat pipe and the flexible heating element:

Providing one or more wires;

Positioning the one or more wires over each of one or more electrical contacts of the flexible heating element; and

The one or more wires are secured to one or more electrical contacts of the flexible heating element.

29. The method of claim 28, wherein securing the one or more wires to one or more electrical contacts of the flexible heating element comprises soldering the one or more wires to one or more electrical contacts of the flexible heating element.

30. The method of claim 28, wherein securing the one or more wires to one or more electrical contacts of the flexible heating element comprises resistance welding the one or more wires to one or more electrical contacts of the flexible heating element.

31. The method of any of claims 24 to 30, further comprising, after securing the temperature sensor to at least one of the heat pipe and the flexible heating element:

providing a heat-shrinkable sleeve configured to decrease in size when heated;

Inserting the heat pipe, the flexible heating element, and the temperature sensor into the heat-shrinkable sleeve; and

Heating the heat pipe, the flexible heating element, the temperature sensor and the heat shrinkable sleeve.

32. The method of claim 31, wherein the heat-shrinkable sleeve comprises a polymer, such as Polyetheretherketone (PEEK).

33. The method of claim 31 or claim 32, wherein heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve comprises heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve at a temperature of at least 300 degrees celsius.

34. The method of any of claims 31-33, wherein heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve comprises heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve at a temperature between about 300 degrees celsius and 400 degrees celsius.

35. The method of any of claims 31-34, wherein heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve comprises heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve at a temperature within 340 degrees celsius or 340 degrees celsius ± 5 degrees celsius.

36. The method of any of claims 31-35, wherein heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve comprises heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve at a temperature of at least 300 degrees celsius for at least 5 seconds.

37. The method of any of claims 31-36, wherein heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve comprises heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve at a temperature between about 300 degrees celsius and 400 degrees celsius for about 5 seconds to about 15 seconds.

38. The method of any of claims 31-37, wherein heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve comprises heating the heat pipe, the flexible heating element, the temperature sensor, and the heat-shrinkable sleeve at a temperature within 340 degrees celsius or 340 degrees celsius ± 5 degrees celsius for 8 seconds to 10 seconds.

39. A tubular heater formed by the method of any one of claims 1 to 38.

40. A tubular heater comprising:

A heat conduction pipe;

A flexible heating element at least partially defining the heat pipe;

A temperature sensor secured to at least one of the heat pipe and the flexible heating element; and

A heat-shrinkable tube defining the heat pipe, the flexible heating element, and the temperature sensor.