ATOMISER ASSEMBLY WITH OSCILLATION CHAMBER

Abstract

An atomiser assembly is provided, including: an oscillation chamber having a cavity containing a liquid to be atomized, a liquid inlet configured to provide a supply of the liquid to be atomized to the cavity, an elastically deformable element, and a mesh element comprising a plurality of nozzles; and an actuator configured to oscillate the elastically deformable element, the oscillation chamber and the liquid being contained in the cavity of the oscillation chamber form an oscillation system, in which oscillation of the elastically deformable element by the actuator varies pressure inside the cavity, and the actuator being further configured to oscillate the elastically deformable element at a resonant frequency of the oscillation system to eject liquid contained in the cavity from the cavity through the plurality of nozzles of the mesh element. An aerosol-generating system, an aerosol-generating device, and a method of operating an atomiser assembly are also provided.

Claims

1.-17. (canceled)

18. An atomiser assembly, comprising: an oscillation chamber having: a cavity containing a liquid to be atomized, a liquid inlet configured to provide a supply of the liquid to be atomized to the cavity, an elastically deformable element, and a mesh element comprising a plurality of nozzles; and an actuator configured to oscillate the elastically deformable element, wherein the oscillation chamber and the liquid contained in the cavity of the oscillation chamber form an oscillation system, wherein oscillation of the elastically deformable element by the actuator varies pressure inside the cavity, and wherein the actuator is further configured to oscillate the elastically deformable element at a resonant frequency of the oscillation system to eject liquid contained in the cavity from the cavity through the plurality of nozzles of the mesh element.

19. The atomiser assembly according to claim 18, wherein the actuator is further configured to oscillate the elastically deformable element at a resonant frequency of the oscillation system that is equal to or greater than a second harmonic of the oscillation system.

20. The atomiser assembly according to claim 18, wherein the oscillation chamber comprises walls defining the cavity configured to receive the liquid to be atomised, wherein a first one of the walls comprises the elastically deformable element, wherein a second one of the walls opposite the first wall comprises the mesh element, and wherein one of the walls comprises the liquid inlet.

21. The atomiser assembly according to claim 20, wherein the actuator is further configured to oscillate the elastically deformable element towards and away from the mesh element.

22. The atomiser assembly according to claim 18, wherein the actuator comprises a piezoelectric element.

23. The atomiser assembly according to claim 22, further comprising a pre-loading element, wherein the piezoelectric element is disposed between the pre-loading element and the elastically deformable element.

24. The atomiser assembly according to claim 23, wherein the piezoelectric element is compressed between the pre-loading element and the elastically deformable element, and wherein the pre-loading element is adjustable to vary compression of the piezoelectric element between the pre-loading element and the elastically deformable element.

25. The atomiser assembly according to claim 18, further comprising a heater configured to heat the liquid to be atomised contained in the cavity of the oscillation chamber.

26. The atomiser assembly according to claim 25, wherein the heater is disposed at or on the mesh element.

27. An aerosol-generating system, comprising: an atomiser assembly according to claim 18; and a liquid reservoir containing a supply of the liquid to be atomised, the liquid reservoir being in fluid communication with the fluid inlet of the oscillation chamber to supply liquid from the liquid reservoir to the cavity of the oscillation chamber.

28. The aerosol-generating system according to claim 27, wherein the system further comprises a cartridge comprising the liquid reservoir and an aerosol-generating device configured to removably receive the cartridge.

29. The aerosol-generating system according to claim 28, wherein the cartridge further comprises the atomiser assembly.

30. The aerosol-generating system according to claim 28, wherein the aerosol-generating device comprises the atomiser assembly.

31. The aerosol-generating system according to claim 30, wherein the aerosol-generating device further comprises a liquid identification system configured to identify the liquid to be atomised contained in the liquid reservoir of the cartridge.

32. The aerosol-generating system according to claim 31, wherein the cartridge further comprises an identifier configured to identify the liquid contained in the liquid reservoir, and wherein the liquid identification system of the aerosol-generating device comprises a detector configured to detect the identifier of the cartridge when the cartridge is received on the aerosol-generating device.

33. An aerosol-generating device, comprising: an atomiser assembly according to claim 18; a power supply; a controller configured to control a supply of power from the power supply to the actuator; and a connector configured to receive a liquid reservoir and to supply liquid from a liquid reservoir to the liquid inlet.

34. A method of operating an atomiser assembly, the atomiser assembly comprising: an oscillation chamber having: a cavity containing a liquid to be atomised, a liquid inlet configured to provide a supply of the liquid to be atomized to the cavity, an elastically deformable element, and a mesh element comprising a plurality of nozzles, and an actuator configured to oscillate the elastically deformable element, wherein the oscillation chamber and the liquid contained in the cavity of the oscillation chamber form an oscillation system; and the method comprising driving the actuator to oscillate the elastically deformable element at a resonant frequency of the oscillation system to eject liquid contained in the cavity from the cavity through the nozzles of the mesh element.

Description

[0137] The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0138] FIG. 1 shows a cross-sectional view of a mesh element of an atomiser assembly according to an embodiment of the present invention;

[0139] FIG. 2 shows a plan view of the mesh element of FIG. 1;

[0140] FIG. 3 shows an enlarged cross-sectional view of a portion of the mesh element of FIG. 1;

[0141] FIG. 4 shows a cross-sectional view of a single nozzle of the mesh element of FIG. 1;

[0142] FIG. 5 shows a cross-sectional view of a single nozzle of the mesh element of FIG. 1 illustrating an alternative outer surface of the second layer;

[0143] FIG. 6 shows a perspective cross-sectional view of an atomiser assembly according to an embodiment of the present invention having the mesh element of FIG. 1; and

[0144] FIG. 7 shows a partially exploded cross-sectional view of an aerosol-generating system according to an embodiment of the present invention.

[0145] FIGS. 1 and 2 show a mesh element 10 for an atomiser assembly according to an embodiment of the present invention. The mesh element 10 comprises a first layer 12 defining a plurality of cylindrical channels 14 and a second layer 16 defining a plurality of nozzles 18. The nozzles 18 are arranged into groups, wherein each group of nozzles 18 overlies one of the channels 14.

[0146] The mesh element 10 also comprises an electrical heating element 19 positioned on the second layer 16. During use, the electrical heating element 19 heats the mesh element 10, which heats liquid being ejected through the nozzles 18.

[0147] FIGS. 3 and 4 show enlarged cross-sectional views of one of the channels 14 and one of the nozzles 18. The first layer 12 comprises a first surface 20 and a second surface 22. The second layer 16 comprises an inner surface 24 facing the second surface 22 of the first layer 12. The second layer 16 also comprises an outer surface 26 on which a hydrophobic coating 28 is provided. The first and second layers 12, 16 are formed from silicon wafers. A buried oxide layer 30 is formed by oxidation of the second surface 22 of the first layer 12 before the first and second layers 12, 16 are bonded together during the manufacture of the mesh element 10.

[0148] Each channel 14 has a minimum diameter 32 and a length corresponding to a thickness 33 of the first layer 12. The minimum diameter 32 of each channel 14 is significantly larger than a maximum diameter 34 of each overlying nozzle 18. Therefore, each channel 14 has a minimum cross-sectional area that is larger than the maximum cross-sectional area of each nozzle 18. As such, the length of the channel 14 does not contribute to a length of each nozzle 18 when determining the pressure required to force a given liquid through each nozzle 18. Advantageously, the thickness 33 of the first layer 12 can be selected to provide the mesh element with a desired strength and rigidity without affecting the pressure required to eject liquid droplets from the nozzles 18.

[0149] Each nozzle 18 has a triangular cross-sectional shape such that each nozzle 18 has a maximum diameter 34 at the inner surface 24 of the second layer 16 and a minimum diameter 36 at the outer surface 26 of the second layer 16. The minimum diameter 36 of each nozzle 18 is selected according to the desired size of liquid droplets to be ejected through the nozzle 18 during use. Each nozzle 18 has a length corresponding to a thickness 38 of the second layer 16. The thickness 38 of the second layer 16 is significantly smaller than the thickness 33 of the first layer 12 to minimise the length of each nozzle 18. The triangular cross-sectional shape of each nozzle 18 and the minimised length of each nozzle 18 reduce or minimise the pressure required to force a given liquid through each nozzle 18.

[0150] As shown in FIG. 5, the outer surface 26 of the second layer 16 may comprise an annular portion 40 of increased thickness surrounding each nozzle 18. The semi-circular cross-sectional shape of each annular portion 40 facilitates separation of liquid droplets from liquid remaining inside each nozzle 18 during use.

[0151] FIG. 6 shows a perspective cross-sectional view of an atomiser assembly 50 comprising the mesh element 10 of FIG. 1. The mesh element 10 is received within a mesh element housing 52. The atomiser assembly 50 also comprises an elastically deformable element 54 and an actuator 56 arranged to oscillate the elastically deformable element 54. The actuator 56 is a piezoelectric actuator.

[0152] The atomiser assembly 50 also comprises a pre-loading element 58 arranged to compress the actuator 56 between the pre-loading element 58 and the elastically deformable element 54. The pre-loading element 58, the actuator 56 and the elastically deformable element 54 are arranged within an actuator housing 60. The actuator housing 60 is attached to the mesh element housing 52 to define a cavity 62 between the mesh element 10 and the elastically deformable element 54. The actuator housing 60 defines a liquid inlet 64 for providing a supply of liquid to be atomised to the cavity 62.

[0153] The elastically deformable element 54 extends radially outward of the mesh element 10, over the mesh element housing 52 to the actuator housing 60. The region of the cavity 62 between the mesh element 10 and the elastically deformable element 54 is substantially circularly cylindrical. The mesh element housing 52 comprises a raised region 63 about the circumference of the mesh element 10, such that the gap between the mesh element housing 52 and the elastically deformable element 54 is narrowed around the circumference of the mesh element 10. The narrow gap between the raised region 63 of the mesh element housing 52 and the elastically deformable element 54 restricts the flow of liquid into and out of the region of the cavity 62 directly between the mesh element 10 and the elastically deformable element 54, which facilitates the generation of a high pressure of the liquid in this region. The outer region of the cavity 62, radially outward from the raised region 63 of the mesh element housing 52, extends partially into the actuator housing 60, to provide a region of the cavity 62 that is able to hold a small volume of liquid outside of the region directly between the mesh element 10 and the elastically deformable element 54. This outer region of the cavity 62 provides a reserve supply of liquid to the region between the mesh element 10 and the elastically deformable element 54 as liquid is depleted from that region during operation. The liquid inlet 64 is provided in the actuator housing 60 to supply liquid to the outer region of the cavity 62. The liquid inlet 64 is arranged offset from the region of the cavity 62 between the mesh element 10 and the elastically deformable element 54. This arrangement of the liquid inlet may reduce the possibility of liquid being pushed out of the cavity through the liquid inlet when subjected to oscillations from the elastically deformable element. This may also reduce the likelihood of air being drawn directly into that region from the liquid inlet 64.

[0154] During use, liquid to be atomised is supplied to the cavity 62 through the liquid inlet 64. The actuator 56 oscillates the elastically deformable element 54 to force at least some of the liquid within the cavity 62 through the channels 14 and the nozzles 18 of the mesh element 10. The liquid forced through the nozzles 18 of the mesh element 10 form droplets. The momentum of the liquid forced through the nozzles 18 to form the droplets carries the droplets away from the mesh element 10. Therefore, during use, the atomiser assembly 50 generates an aerosol comprising liquid droplets ejected through the mesh element 10.

[0155] FIG. 7 shows a cross-sectional view of an aerosol-generating system 70 according to an embodiment of the present invention. The aerosol-generating system 70 comprises an aerosol-generating device 72 and a liquid reservoir 74.

[0156] The aerosol-generating device 72 comprises a housing 76 comprising a first housing portion 78 and a second housing portion 80. A controller 82 and a power supply 84 comprising a battery are positioned within the first housing portion 78. A mouthpiece 85 defining a mouthpiece channel 87 is connectable to the second housing portion 80.

[0157] The second housing portion 80 defines a liquid reservoir chamber 86 for receiving the liquid reservoir 74. The first housing portion 78 is detachable from the second housing portion 80 to allow replacement of the liquid reservoir 74.

[0158] The aerosol-generating device 72 also comprises a device connector 88 positioned within the liquid reservoir chamber 86 for engagement with a reservoir connector 90 that forms part of the liquid reservoir 74.

[0159] The aerosol-generating device 72 comprises the atomiser assembly 50 of FIG. 6 positioned within the second housing portion 80. The liquid inlet 64 of the atomiser assembly 50 is in fluid communication with the device connector 88. The mesh element 10 of the atomiser assembly 50 is positioned within an aerosol chamber 92 defined by the second housing portion 80.

[0160] The liquid reservoir 74 comprises a container 94 and a liquid aerosol-forming substrate 96 positioned within the container 94. When the reservoir connector 90 is engaged with the device connector 88, liquid aerosol-forming substrate 96 from the liquid reservoir 74 is supplied to the cavity 62 of the atomiser assembly 50 through the reservoir connector 90, the device connector 88, and the liquid inlet 64 of the atomiser assembly 50.

[0161] When the first housing portion 78 is connected to the second housing portion 80, the controller 82 controls a supply of power from the power supply 84 to the actuator 56 to eject droplets of the liquid aerosol-forming substrate 96 into the aerosol chamber 92 from the mesh element 10. The controller 82 comprises a memory storing frequency calibration data. The frequency calibration data comprises information corresponding to the power required to be supplied to the actuator 56 to oscillate the elastically deformable element 54 at a resonant frequency of the oscillation system. During operation, the controller 82 accesses the frequency calibration data stored on the memory and controls the power supplied to the actuator 56 based on the frequency calibration data such that the elastically deformable element 54 is oscillated at a resonant frequency of the oscillation system.

[0162] The second housing portion 80 defines an air inlet 98 and an air outlet 100 each in fluid communication with the aerosol chamber 92. During use, a user draws on the mouthpiece 85 to draw air into the aerosol chamber 92 through the air inlet 98. The air flows through the aerosol chamber 92 where droplets of liquid aerosol-forming substrate 96 ejected from the mesh element 10 are entrained within the airflow to form an aerosol. The aerosol flows out of the aerosol chamber 92 through the air outlet 100 and is delivered to the user through the mouthpiece channel 87.

[0163] The aerosol-generating device 72 also comprises an airflow sensor 102 positioned within the aerosol chamber 92. The airflow sensor 102 is arranged to provide a signal to the controller 82 indicative of a user drawing on the mouthpiece 85. The controller 82 is arranged to supply power from the power supply 84 to the actuator 56 of the atomiser assembly 50 only when the controller receives a signal from the airflow sensor 102 indicative of a user drawing on the mouthpiece 85.