A Heater Assembly for an Aerosol Generating System

The present disclosure relates to a heater assembly for an aerosol-generating system, a device comprising the heater assembly, a cartridge for use with the heater assembly, an aerosol-generating system comprising the device and the cartridge, and methods of using the heater assembly.

Aerosol-generating systems configured to generate an aerosol from an aerosol-forming substrate, such as a tobacco-containing substrate, are known in the art. Many known aerosol-generating systems generate aerosol by the application of heat to the substrate by a heater assembly. In electrically operated aerosol-generating systems, heat is applied to the substrate when the heater assembly is supplied with power from a power supply. The generated aerosol can then be inhaled by a user of the device.

In many aerosol-generating devices, a heater element of the heater assembly is configured to heat a quantity of aerosol-forming substrate contained in a porous material such as a wick or capillary element provided adjacent to or in contact with the heater element. The porous material can transport aerosol-forming substrate in liquid form from a reservoir provided in the aerosol-generating system. In this way, aerosol-generating substrate in the vicinity of the heater element that is vaporised during use of the aerosol-generating system is continuously replenished.

Efficient heating of aerosol-forming substrate contained in the porous material is desirable to reduce the power requirements of the heater assembly. This is particularly important when the aerosol-generating system is portable and comprises a portable power supply such as a battery. Heating of the aerosol-forming substrate contained in the porous material may be efficient when there is direct contact between the porous material and the heater element. An example of such a heater assembly comprises a resistive heating element in the form of a coil of wire wrapped around a wick. At least one end of the wick extends into a reservoir of aerosol-forming substrate.

One problem with aerosol-generating systems in which a heater element is in direct contact with a porous material, such as a coil and wick type arrangement, is that, over the course of many heating cycles, the porous material can degrade. Degradation can be caused by heating of the porous material. Degradation can also be caused by chemical interactions between the aerosol-forming substrate and the porous material, mechanical stress on the porous material and particle accumulations on the surface of the porous material. Degradation of the porous material can result in less efficient heat transfer between the heating element and the porous material and less efficient transfer of liquid from the reservoir towards the heater element by the porous material. As such, the porous material has a limited useful lifetime. The useful lifetime of the porous material is typically significantly shorter than the lifetime of other components of the aerosol-generating system, for example the heater element. It is not typically possible to replace a degraded porous material without taking the system, and the heater assembly, apart. This is not something that a normal consumer is capable of doing or is inclined to do.

Some aerosol-generating systems comprise a reusable aerosol-generating device and a disposable cartridge. The disposable cartridge comprises the aerosol-forming substrate and, when the aerosol-forming substrate is depleted, the cartridge can be replaced. Such cartridges can comprise the heater element and the porous material, for example the cartridge can comprise a coil and wick type arrangement. In such cases, the heater element and the porous material are disposed of along with the rest of the cartridge when the aerosol-forming substrate of the cartridge is depleted.

When the porous material is provided in a disposable cartridge, it will generally be disposed of and replaced before significant degradation as occurred and so the problem of degradation of the porous material may be avoided. However, including both the heater element and the porous material in the cartridge increases the material cost of the cartridge and the complexity of the cartridge.

More generally, high speed manufacturing of a heater element and porous material provided together and in contact with one another is difficult with at least some of the steps of the manufacturing process required to be performed by hand. In particular, high speed manufacturing of coil and wick-type arrangements is difficult. This further increases the cost of manufacturing cartridges comprising a heater element and porous material.

It would be desirable to provide a heater assembly for an aerosol-generating system in which efficient heating of an aerosol-forming substrate contained in a porous material is achieved during use. It would be desirable to provide such a heater assembly wherein degradation of components of the system, in particular the heater assembly and the porous material, is reduced compared to prior art systems, particularly compared to coil and wick type arrangements. It would further be desirable to provide such a heater assembly that is cheaper and easier to manufacture. In the context of an aerosol-generating systems comprising a disposable cartridge, it would be desirable to provide a cartridge that is cheap, simple to manufacture and that has lower a material cost.

According to a first aspect of the present disclosure there is provided a heater assembly for an aerosol-generating system. The heater assembly may comprise a heating element. The heater assembly may comprise a receiving chamber. The receiving chamber may be at least partially defined by the heating element. The receiving chamber may comprise an opening. The opening may be for receiving a wicking element of the aerosol-generating system.

The receiving chamber may have a first configuration. The receiving chamber may have a second configuration. An internal volume of the receiving chamber may be larger when the receiving chamber is in the first configuration than when the receiving chamber is in the second configuration. In the second configuration, the heating element may be in contact with the wicking element when the wicking element is received in the receiving chamber.

The receiving chamber having the first and second configuration may advantageously provide a simple and effective means by which the heater assembly can be coupled or decoupled from a wicking element received in the receiving chamber. By providing two configurations in this way, the heating element need not always be in contact with the wicking element received in the receiving chamber.

When the receiving chamber is in the second configuration, and when the wicking element is received in the receiving chamber, the contact between the heating element and the wicking element may advantageously provide for efficient heating of the wicking element by the heating element. Aerosol-forming substrate contained in the wicking element may be heated efficiently when the receiving chamber is in the second configuration. Efficient heating may advantageously be achieved because the contact between the heating element and the wicking element allows for heat conduction. Furthermore, the contact between the heating element and the wicking element may draw liquid out of the wicking element to the heating element.

When the receiving chamber is in the second configuration, and when the wicking element is received in the receiving chamber, the heater assembly may be referred to as being coupled to the wicking element.

When the receiving chamber is in the first configuration, the wicking element may be receivable and removable from the receiving chamber. The internal volume of the receiving chamber being larger when the receiving chamber is in the first configuration may advantageously mean that the heating element is not in contact with the wicking element in the first configuration of the receiving chamber such that the heater assembly is not coupled to the wicking element and the wicking element is removable.

The heater assembly may advantageously be provided as a separate component to the wicking element. The wicking element received in the receiving chamber may advantageously be replaceable separately from the heater assembly. For example, the wicking element may be replaced when it is degraded. In particular, the wicking element may advantageously be replaceable when the receiving chamber is in the first configuration without the need to disassemble the heater assembly.

Because the heater assembly can be provided as a separate component to the wicking element, the two components may advantageously be manufactured separately. Therefore, high speed manufacturing techniques may be used to manufacture the heater assembly separately from the wicking element. This might not be possible if the two components were manufactured together. For example, winding of a wick around a capillary element is difficult to achieve in a high speed automated process.

Preferably, the heater assembly may be provided as part of an aerosol-generating device. The aerosol-generating device may be configured to be used with a cartridge comprising the wicking element. The wicking element may be configured to be receivable in the receiving chamber of the heater assembly. Therefore, to use the cartridge with the aerosol-generating device, the wicking element may be insertable into the receiving chamber when the receiving chamber is in the first configuration. In use of the heater assembly to heat aerosol-forming substrate, the receiving chamber may be in the second configuration.

The aerosol-generating device may be reusable. The cartridge may be disposable. When the cartridge is to be disposed of, the receiving chamber can simply be placed in the first configuration to decouple the heater assembly from the wicking element and the cartridge be disposed of and replaced. The heater assembly may be reused. The material cost of such a cartridge is reduced compared to a cartridge that comprises both the heater assembly and the wicking element.

Providing a heater assembly which can be coupled and uncoupled from a wicking element may advantageously reduce degradation of at least one of the heating element and the wicking element received in the receiving chamber.

Degradation of the heating element and the wicking element may be caused by contact between the at least one heating element and the wicking element received in the receiving chamber of the heater assembly. A heater assembly comprising a receiving chamber having the first and second configurations may allow for reduced contact between the at least one heating element and a wicking element received in the receiving chamber compared to a heater assembly in which there is permanent contact between a heating element and a wicking element. This may reduce the degradation of the wicking element.

For example, the receiving chamber may be placed in the second configuration only during use of the aerosol-generating system when the heating element is used to heat the wicking element. Otherwise, the receiving chamber may be placed in the first configuration. In this way, the heating element may be in contact with the wicking element only during heating of the wicking element to ensure efficient heating of the wicking element is achieved. This may significantly reduce the length of time that there is contact between the heating element and the wicking element. This may advantageously extend the lifetime of the wicking element.

The heating element may be moveable or deformable to reduce the internal volume of the receiving chamber in the second configuration relative to the first configuration. The heating element may be moved or deformed in the second configuration relative the first configuration so as to contact a wicking element received in the receiving chamber.

The heater assembly may comprise an actuator. The actuator may be configured to move or deform the heating element for transition of the receiving chamber from the first configuration to the second configuration. The actuator may be configured to move or deform the heating element to reversibly configure the receiving chamber between the first configuration and the second configuration.

The receiving chamber may be configured such that the wicking element is receivable in the receiving chamber along a longitudinal direction. The longitudinal direction may define a central axis through the receiving chamber.

At least a first portion of the heating element may be closer to the central axis in the second configuration than in the first direction.

At least a first component of the motion of the first portion of the heating element when the heating element is moved or deformed may be perpendicular to the longitudinal direction. The actuator may be configured such that the first component of the motion of the first portion of the heating element may be towards the central axis when the receiving chamber is reconfigured from the first configuration to the second configuration.

The heating element may comprise a second portion different to the first portion. In the second configuration of the receiving chamber, the second portion of the heating element May not contact a wicking element when the wicking element is received in the receiving chamber.

The second portion of the heating element may have a lower resistance per unit length than the first portion of the heating element. This may advantageously ensure that the second portion of the heating element is maintained at a lower temperature than the first portion of the heating element.

The second portion of the heating element may comprise or consist of material having a resistivity that is lower than the resistivity of a material of the first portion of the heating element. Providing such a material may advantageously result in the second portion of the heating element having a lower resistance per unit length than the first portion of the heating element. The second portion of the heating element may comprise a coating. The coating may comprise a material having a resistivity that is lower than the resistivity of a material of the first portion of the heating element.

The second portion of the heating element may have a cross-sectional area that is larger than the first portion. This may advantageously result in the second portion of the heating element having a lower resistance per unit length than the first portion of the heating element. In such cases, the second portion of the heating element may consist of the same material or materials as the first portion of the heating element.

In the first configuration, the receiving chamber may be configured such that the wicking element is freely removable or receivable within the receiving chamber. This may be achieved as a result of the heating element not contacting the wicking element received in the receiving chamber when the receiving chamber is in the first configuration.

In the second configuration, the receiving chamber may be configured to apply a retaining force on the wicking element when a wicking element is received in the receiving chamber. The retaining force may be at least partially applied by the heating element. The retaining force may advantageously ensure that there is contact between the heating element and the wicking element received in the receiving chamber to provide efficient heating.

The heating element may comprise or consist of a resilient material. This may be particularly advantageous when the heating element is deformable to reduce the internal volume of the receiving chamber. The heating element may be deformed in the second configuration relative to the first configuration. A heating element comprising or consisting of a resilient material may advantageously return to the shape of the first configuration when released from the second configuration.

The internal volume of the receiving chamber may be at least 5% larger, preferably at least 10% larger, preferably at least 15% larger, preferably at least 20%, even more preferably at least 30% and even more preferably at least 50% larger when the receiving chamber is in first configuration than when the receiving chamber is in the second configuration.

Preferably, the receiving chamber has an axisymmetric shape, at least in the first configuration. The axis of symmetry of the axisymmetric shape is preferably the central axis that is parallel to the longitudinal direction. Preferably, the receiving chamber is cylindrical in at least the first configuration.

The receiving chamber may have an axis symmetric shape in the second configuration. The axis of symmetry of the axisymmetric shape is preferably the central axis that is parallel to the longitudinal direction. Preferably, the receiving chamber is cylindrical the second configuration.

At least in the first configuration, the receiving chamber may have a width of between 1 millimeter and 12 millimeters, preferably between 3 millimeters and 7 millimeters. If the receiving chamber is cylindrical, the values for the width correspond to values for the diameter of the cylindrical chamber.

A cross-sectional dimension of the receiving chamber may be larger when the when the receiving chamber is in first configuration than when the receiving chamber is in the second configuration. The cross-sectional dimension may be a cross-sectional area or a width of a cross-section of the receiving chamber. When the receiving chamber is cylindrical, the cross-sectional dimension may be the diameter of the receiving chamber.

The cross-sectional dimension of the receiving chamber may be at least 5% larger, preferably at least 10% larger, preferably at least 15% larger, preferably at least 20%, even more preferably at least 30% and even more preferably at least 50% larger when the receiving chamber is in first configuration than when the receiving chamber is in the second configuration.

The cross-sectional dimension may be a dimension of a cross-section of the receiving chamber that is perpendicular to the longitudinal direction.

The heating element may comprise a coil. The coil may be wound around the central axis. The receiving chamber may be at least partially defined by the coil.

The coil may have an electrical resistance of between 0.4 ohms to 4 ohms.

The coil may be formed by a coil of wire. The wire may have a diameter of between 0.1 millimeters and 1 millimeter, preferably between 0.2 millimeters and 0.5 millimeters. The length of the wire may be between 10 millimeters and 150 millimeter, preferably between 20 millimeter and 50 millimeter.

The coil may be deformable to reduce the internal volume of the receiving chamber in the second configuration relative to the first configuration. The heater assembly may comprise an actuator configured to deform the coil for transition of the receiving chamber from the first configuration to the second configuration.

In the second configuration of the receiving chamber, at least a first portion of the coil may contact the wicking element when the wicking element is received in the receiving chamber.

The heating element may comprise a first end and a second end. The coil may be defined between the first end and the second end.

The first and second ends of the heating element may further comprise or form one or more contact portions. The first and seconds ends of the heating element may not be in the shape of a coil.

The first and second contact portions may advantageously be mechanically connected to, or connectable to, the actuation means. The actuation means may be configured to deform the heating element by manipulating the first and second contact portions.

Preferably, the first and second contact portions are electrical contact portions. The first heater element may advantageously be connectable to a power supply via the first and second electrical contact portions. The power supply may be external to the heater assembly. For example, an aerosol-generating device that comprises the heater assembly may also comprise the power supply.