A HEATING ELEMENT HAVING INCREASED RESISTANCE

Abstract

There is provided a heating element (11) for an aerosol-generating system, the heating element (11) comprising a mesh (12). The mesh (12) comprises a plurality of first filaments (20) extending in a first direction (21), wherein each of the first filaments (20) comprises a first end (24) and a second end (26). The mesh (12) also comprises a plurality of second filaments (22) extending in a second direction (23), wherein the first direction (21) is perpendicular to the second direction (23). Each of the second filaments (22) comprises a third end (28) and a fourth end (30). The second ends (26) of the first filaments (20) are electrically connected to the third ends (28) of the second filaments (22).

Claims

1. A heating element for an aerosol-generating system, the heating element comprising a mesh, the mesh comprising: a plurality of first filaments extending in a first direction, wherein each of the first filaments comprises a first end and a second end; a plurality of second filaments extending in a second direction, wherein the first direction is perpendicular to the second direction, and wherein each of the second filaments comprises a third end and a fourth end; and wherein the second ends of the first filaments are electrically connected to the third ends of the second filaments.

2. A heating element according to claim 1, further comprising an electrically conductive portion extending between the second ends of the first filaments and the third ends of the second filaments.

3. A heating element according to claim 2, wherein the first filaments comprise a first material having a first electrical conductivity, wherein the second filaments comprise a second material having a second electrical conductivity, wherein the electrically conductive portion comprises a third material having a third electrical conductivity, and wherein the third electrical conductivity is greater than both the first electrical conductivity and the second electrical conductivity.

4. A heating element according to claim 2, wherein the electrically conductive portion comprises at least one of silver, gold and platinum.

5. A heating element according to claim 1, wherein each of the first filaments comprises stainless steel.

6. A heating element according to an claim 1, wherein each of the second filaments comprises stainless steel.

7. A heating element according to claim 1, wherein the mesh is a woven mesh.

8. A heater assembly for an aerosol-generating system, the heater assembly comprising: a heating element according to claim 1; a first electrical contact connected to the first end of at least one of the first filaments; and a second electrical contact connected to the fourth end of at least one of the second filaments.

9. A heater assembly according to claim 8, further comprising a substrate defining an aperture extending through the substrate, wherein at least part of the heating element overlies the aperture, and wherein each of the first electrical contact and the second electrical contact is provided on the substrate.

10. A heater assembly according to claim 9, further comprising an electrically conductive portion extending between the second ends of the first filaments and the third ends of the second filaments.

11. A heater assembly according to claim 10, wherein the electrically conductive portion is provided on the substrate.

12. A heater assembly according to claim 8, further comprising a transport material for conveying a liquid aerosol-forming substrate to the heating element.

13. A cartridge for an aerosol-generating system, the cartridge comprising: a heater assembly according to claim 8; and a liquid storage compartment for holding a liquid aerosol-forming substrate.

14. An aerosol-generating system comprising: a cartridge according to claim 13; and an aerosol-generating device arranged to be removably coupled to the cartridge, the aerosol-generating device comprising a power supply for supplying electrical power to the heating element.

Description

[0093] Examples will now be further described with reference to the figures in which:

[0094] FIG. 1 is a schematic side view of a heater assembly in accordance with an example of the present disclosure;

[0095] FIG. 2 is schematic top view of the heater assembly of FIG. 1;

[0096] FIG. 3 is a schematic side cross-sectional view of an example aerosol-generating system comprising a cartridge and an aerosol-generating device; and

[0097] FIG. 4 a schematic side cross-sectional view of the aerosol-generating system of FIG. 3 rotated through 90 degrees about the longitudinal axis of the aerosol-generating system.

[0098] Referring to FIGS. 1 and 2, there is shown a heater assembly 10 comprising a heating element 11 and a ceramic transport material 14.

[0099] The heating element 11 comprises an electrically conductive mesh 12 arranged on a substrate 13. The mesh 12 is woven and comprises a plurality of first filaments 20 extending in a first direction 21 and a plurality of second filaments 22 extending in a second direction 23 perpendicular to the first direction 21. Each of the first filaments 20 has a first end 24 and a second end 26. Each of the second filaments 22 has a third end 28 and a fourth end 30. Each of the first and second filaments 20, 22 is formed from stainless steel.

[0100] A first electrical contact 32 is arranged on the substrate 13 and is electrically connected to the first ends 24 of the first filaments 20. A second electrical contact 34 is arranged on the substrate 13 and is electrically connected to the fourth ends 30 of the second filaments 22. An electrically conductive portion 36 is arranged on the substrate 13 and electrically connects the second ends 26 of the first filaments 20 to the third ends 28 of the second filaments 22. The electrically conductive portion 36 is formed from a material having an electrical conductivity that is higher than the electrical conductivity of the stainless steel forming the first and second filaments 20, 22. For example, the electrically conductive portion 36 may be formed from brass or copper. During use, a voltage is applied across the first and second electrical contacts 32, 34 to drive an electric current through the first filaments 20 and the second filaments 22 via the electrically conductive portion 36.

[0101] In the example shown in FIG. 2, the first electrical contact 32 is connected to a positive terminal of a DC power supply and the second electrical contact 34 is connected to the negative terminal of the DC power supply. The resulting electric current flows from the first electrical contact 32 along the first filaments 20 to the electrically conductive portion 36, and from the electrically conductive portion 36 along the second filaments 22 to the second electrical contact 34, as illustrated by the dashed line 38. The electric current flowing through the first filaments 20 and the second filaments 22 resistively heats the mesh 12. Advantageously, the electrically conductive portion 36 facilitates resistive heating along the length of both the first filaments 20 and the second filaments 22.

[0102] The skilled person will appreciate that the arrangement illustrated in FIG. 2 is only exemplary, and the polarity of the first and second electrical contacts 32, 34 can be reversed. It is also possible to electrically connect the first and second electrical contacts 32, 34 to opposite terminals of an AC power supply.

[0103] The ceramic transport material 14 is in direct contact with the mesh 12 via an aperture 15 in the substrate 13. The ceramic transport material 14 is arranged to convey a liquid aerosol-forming substrate to the mesh 12. A plurality of interstices 16 are defined between the first and second filaments 20, 22 of the mesh 12. During heating, vaporised aerosol-forming substrate is released from the heater assembly 10 via the interstices 16 to generate an aerosol.

[0104] FIG. 3 is a schematic cross-sectional view of an example aerosol-generating system. FIG. 4 shows the same cross-sectional view with the aerosol-generating system rotated through 90 degrees about its longitudinal axis.

[0105] The aerosol-generating system comprises two main components, a cartridge 100 and an aerosol-generating device 200. A connection end 115 of the cartridge 100 is removably connected to a corresponding connection end 205 of the aerosol-generating device 200. The connection end 115 of the cartridge 100 and connection end 205 of the aerosol-generating device 200 each have electrical contacts or connections (not shown) which are arranged to cooperate to provide an electrical connection between the cartridge 100 and the aerosol-generating device 200. The aerosol-generating device 200 contains a power supply 210 in the form of a battery, which in this example is a rechargeable lithium ion battery, and control circuitry 220. The aerosol-generating system is portable and has a size comparable to a conventional cigar or cigarette. A mouthpiece 125 is arranged at the end of the cartridge 100 opposite the connection end 115.

[0106] The cartridge 100 comprises a cartridge housing 105 containing the heater assembly 10 of FIGS. 1 and 2 and a liquid storage compartment having a first storage portion 130 and a second storage portion 135. A liquid aerosol-forming substrate is held in the liquid storage compartment. As shown in FIG. 4, the first storage portion 130 of the liquid storage compartment is connected to the second storage portion 135 of the liquid storage compartment by an annular part of the first storage portion 130. Therefore, liquid aerosol-forming substrate in the first storage portion 130 can pass to the second storage portion 135. The heater assembly 10 receives liquid from the second storage portion 135 of the liquid storage compartment. At least a portion of the ceramic transport material 14 of the heater assembly 10 extends into the second storage portion 135 of the liquid storage compartment to contact the liquid aerosol-forming substrate therein.

[0107] An air flow passage 140, 145 extends through the cartridge 100 from an air inlet 150 formed in a side of the cartridge housing 105, past the mesh 12 of the heater assembly 10, and from the heater assembly 10 to a mouthpiece opening 110 formed in the cartridge housing 105 at an end of the cartridge 100 opposite to the connection end 115.

[0108] The components of the cartridge 100 are arranged so that the first storage portion 130 of the liquid storage compartment is between the heater assembly 10 and the mouthpiece opening 110, and the second storage portion 135 of the liquid storage compartment is positioned on an opposite side of the heater assembly 10 to the mouthpiece opening 110. In other words, the heater assembly 10 lies between the first and second portions 130, 135 of the liquid storage compartment and receives liquid from the second storage portion 135. The first storage portion 130 of the liquid storage compartment is closer to the mouthpiece opening 110 than the second storage portion 135 of the liquid storage compartment. The air flow passage 140, 145 extends past the mesh 12 of the heater assembly 10 and between the first 130 and second 135 portions of the liquid storage compartment.

[0109] The aerosol-generating system is configured so that a user can puff or draw on the mouthpiece 125 of the cartridge to draw aerosol into their mouth through the mouthpiece opening 110. In operation, when a user puffs on the mouthpiece 125, air is drawn through the airflow passage 140, 145 from the air inlet 150, past the heater assembly 10, to the mouthpiece opening 110. The control circuitry 220 controls the supply of electrical power from the power supply 210 to the cartridge 100 when the system is activated. This in turn controls the amount and properties of the vapour produced by the heater assembly 10. The control circuitry 220 may include an airflow sensor (not shown) and the control circuitry 220 may supply electrical power to the heater assembly 10 when user puffs are detected by the airflow sensor. This type of control arrangement is well established in aerosol-generating systems such as inhalers and e-cigarettes. When a user puffs on the mouthpiece opening 110 of the cartridge 100, the heater assembly 10 is activated and generates a vapour that is entrained in the air flow passing through the air flow passage 140. The vapour cools within the airflow in passage 145 to form an aerosol, which is then drawn into the user's mouth through the mouthpiece opening 110.

[0110] In operation, the mouthpiece opening 110 is typically the highest point of the system. The construction of the cartridge 100, and in particular the arrangement of the heater assembly 10 between the first and second storage portions 130, 135 of the liquid storage compartment, is advantageous because it exploits gravity to ensure that the liquid aerosol-forming substrate is delivered to the heater assembly 10 even when the liquid storage compartment is becoming empty, but prevents an oversupply of liquid to the heater assembly 10 which might lead to leakage of liquid into the air flow passage 140.