CONTINUOUS MODE HEATER ASSEMBLY FOR AEROSOL-GENERATING SYSTEM

Abstract

A heater assembly for an aerosol-generating system is provided, including a heater element; a reservoir including aerosol-generating liquid; and a condenser configured to condense excess vapors generated in the heater assembly, such that condensate is at least partially conveyed back into the reservoir. A method of manufacturing a heater assembly for an aerosol-generating system is also provided.

Claims

1.-15. (canceled)

16. A heater assembly for an aerosol-generating system, comprising: a heater element; a reservoir comprising aerosol-generating liquid; and a condenser configured to condense excess vapors generated in the heater assembly, such that condensate is at least partially conveyed back into the reservoir.

17. The heater assembly according to claim 16, wherein the condenser is disposed in direct vicinity to the aerosol-generating liquid.

18. The heater assembly according to claim 16, wherein the condenser is a non-porous, non-absorbing, material.

19. The heater assembly according to claim 18, wherein the material is a polymeric material, a metallic material, or a ceramic material.

20. The heater assembly according to claim 16, wherein the condenser has a conical shape and a hole at an apex thereof, wherein the condensate is at a conical surface of the condenser viewed from a direction pointing to the heater assembly, and wherein the is further configured such that the condensate flows along the conical surface and drops onto the heater assembly.

21. The heater assembly according to claim 16, wherein the reservoir further comprises a porous material in which the aerosol generating liquid is absorbed.

22. The heater assembly according to claim 16, wherein the reservoir is removably disposed in the heater assembly.

23. The heater assembly according to claim 16, wherein the heater element is a resistive heater having a resistance between 0.1 Ohm and 10 Ohms.

24. The heater assembly according to claim 16, wherein the heater element is a resistive heater having a resistance of about 1.5 Ohms.

25. The heater assembly according to claim 16, wherein the heater assembly has an operating temperature in a range of between about 100° C. and about 200° C.

26. The heater assembly according to claim 16, wherein the aerosol-generating liquid comprises from 0.1% by weight to 10% by weight of nicotine.

27. The heater assembly according to claim 16, wherein the aerosol-generating liquid comprises from about 1% by weight to about 2% by weight of nicotine.

28. The heater assembly according to claim 16, wherein the aerosol-generating liquid comprises from 20% by weight to 60% by weight of compounds having a vapor pressure at 200° C. being at least 20% of a vapor pressure of nicotine at 200° C.

29. The heater assembly according to claim 16, wherein the aerosol-generating liquid comprises from 30% by weight to 50% by weight of compounds having a vapor pressure at 200° C. being at least 50% of a vapor pressure of nicotine at 200° C.

30. The heater assembly according to claim 16, wherein the aerosol-generating liquid comprises from 40% by weight to 80% by weight of compounds having a vapor pressure at 200° C. being less than 50% of a vapor pressure of nicotine at 200° C.

31. The heater assembly according to claim 16, wherein the aerosol-generating liquid comprises from 50% by weight to 70% by weight of compounds having a vapor pressure at 200° C. being less than 30% of a vapor pressure of nicotine at 200° C.

32. An aerosol-generating system, comprising: a heater assembly comprising a heater element; a reservoir comprising aerosol-generating liquid; and a condenser configured to condense excess vapors generated in the heater assembly, such that condensate is at least partially conveyed back into the reservoir.

33. The aerosol-generating system according to claim 32, further comprising a housing having at least two parts, wherein a first part of the at least two parts comprises a mouthpiece, the condenser, and the heater element, wherein a second part of the at least two parts comprises a power source, control circuitry, and a support for the reservoir, and wherein the reservoir is disposed between the first part and the second part, and is held between the heater element and the support in the housing.

34. The aerosol-generating system according to claim 32, further comprising an air flow path from an air inlet through an aerosol-formation chamber comprising the heater assembly to the mouth piece, wherein blocking means for blocking air flow are provided in the air flow path.

35. A method of manufacturing a heater assembly for an aerosol-generating system, comprising: providing a heater element; providing a reservoir comprising aerosol-generating liquid, the reservoir being disposed in thermal contact with the heater element; and providing a condenser being configured to condense excess vapors generated in the heater assembly, such that condensate is at least partially conveyed back into the reservoir.

Description

[0033] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0034] FIG. 1 shows a heater assembly according to the present invention;

[0035] FIG. 2 shows individual components of the heater assembly as used in an e-cigarette;

[0036] FIG. 3 shows the changing procedure for exchanging the liquid reservoir in an e-cigarette with two-part housing;

[0037] FIG. 4 shows an embodiment of an e-cigarette wherein the condenser is used as secondary heater; and

[0038] FIG. 5 shows an alternative embodiment of an e-cigarette comprising a secondary heater.

[0039] FIG. 1 shows the heater assembly of the present invention, comprising a support 10, a reservoir 12 for the e-liquid, a heater element 14 and a condenser 16. The reservoir 12 is placed on the support 10 and is sandwiched between the support 10 and the heater element 14. In peripheral areas of the support two feedthroughs 18 for the electrical contact portions 15 of the heater element 14 are provided. The heater element 14 is a flat etched stainless steel heater having a generally planar surface. The reservoir 12 is a generally cylindrical porous polymer disc made from thermo-resistant PET polymer. The thickness of the reservoir is about 2 millimetres. The reservoir 12 can store up to 250 milligramms of e-liquid. The e-liquid may have a composition of glycerol 50%, Propylene glycol 37%, nicotine 2%, water 10%, flavours 1% and the operating temperature of the heater element is 130 to 150 degree Celsius. The e-liquid may have a composition of glycerol 70%, Propylene glycol 14%, nicotine 2%, water 13%, flavours 1% and the operating temperature of the heater element is 150 to 200 degree Celsius.

[0040] In FIG. 2 an e-cigarette with a two-part housing comprising the heater assembly of FIG. 1 is depicted. For the sake of clarity only the second part of the housing 20 comprising a power source (not shown), electric circuitry (not shown) and an air inlet (not shown) is depicted. On the top side of the part 20, electric contacts 22 for contacting the power source to the heater element 14 and air flow slit 24 are provided. Support 10 is placed on top of part 20, such that the feedthroughs 18 of the support 10 coincide with the electric contacts 22 of part 20. The support 10 also comprises slits 26 such that air can flow therethrough.

[0041] On the support 10 reservoir 12 is placed. The reservoir is laterally surrounded by a circular element 30 that ensures radial localization of the reservoir 12. The circular element also has feedthroughs 32 for electric contacts 15 of the heater element. The outer dimensions of the circular element 30 correspond to the outer dimensions of the support 12. The circular element 30 has a thickness such that its top edge lies in the same plane as the upper surface of the reservoir 12. Heater element 14 is placed on top of the reservoir 12 and its electric contact portions 15 are inserted into the feedthroughs and connected to the below contacts 22 and via these contacts to the power source located in the second part 20 of the housing. Above the heater element 14 a cylindrical element 34 forming the side walls of the aerosol formation chamber 36. A condenser 16 forming the top wall of the aerosol formation chamber 36 is placed above cylindrical element 34. The condenser 16 has a conical shape with the conical apex pointing away from the heater element 14. At the apex of the conical condenser 16 a hole 38 is provided through which aerosol may leave the aerosol formation chamber 36. During a puff an air stream is created through the aerosol formation chamber and aerosol is inhaled by the consumer through the mouthpiece of the e-cigarette. The heater assembly is operated in continuous mode such that also between puffs e-liquid is vaporized. A large part of these excess vapors is condensed at the interior surface of the condenser. Due to the conical shape of the condenser the condensate flows along the side walls of the aerosol formation chamber and returns to the heater element and the surface of the reservoir in direct vicinity of the heater element.

[0042] In FIG. 3 the e-cigarette of FIG. 2 including the first part 40 of the two-part housing is depicted. The first part 40 includes a mouthpiece portion 42. At its lower end 44 the first part 40 of the housing comprises the condenser 16, the cylindrical element 34 the heater element 14 and the circular element 30 (not visible in FIG. 3). The heater element 14 is preferably replaceable such that upon a defect of the heater element 14, only the heater element 14 itself and not the complete first part 40 of the housing needs to be renewed. In order to insert or replace the reservoir 12 the two parts 20, 40 of the two-part housing are disconnected. The reservoir 12 is replaced or inserted on the support 10 and the two parts 20, 40 are reconnected again. In the embodiment shown in FIG. 3, the two parts 20, 40 of the housing are connected by a clamping connection.

[0043] FIG. 4 shows a further embodiment of the invention. The reservoir is a cylindrical container 50 comprising e-liquid absorbed in a porous material 52, and comprising an opening 54 at the lower end. A primary heater 56 is provided in the opening 54 of the container 50. The condenser is a secondary heater element 58. The secondary heater element 58 is activated only during a puff. Between puffs the secondary heater assembly 58 acts as condenser and excess vapours generated by the continuously operated primary heater element 56 are condensed at the secondary heater 58. An air flow channel 62 is defined between air inlets 60 and an outlet 64 of the aerosol forming chamber. Control circuitry 66 and a power supply 68 are provided for controlling and powering the heater elements 56, 58. When a user draws a puff the secondary heater element 58 is activated such that the condensed vapours adhering to the secondary heater element 58 are vaporized.

[0044] In FIG. 5 another embodiment of the invention is depicted. The heater assembly comprises a housing 70 with two openings 72, 74 at opposite sides of the housing 70. The housing 70 comprises porous liquid absorbing material for holding liquid aerosol generating substrate. A primary fluid permeable heater 76 is provided at the first opening 72 of the housing 70 and is connected to an exhaust flow portion 78 within the aerosol generating system. The primary heater 76 is continuously operated and continuously evaporated e-liquid that is exhausted from the system via the exhaust flow portion 78. The second opening 74 is provided with a secondary heater 80 which is only activated during puffs. The second opening 47 is connected to the air flow path 84 between an air inlet 82 and a mouthpiece. When a user draws a puff the aerosol generated by the secondary heater 80 is inhaled by the consumer.