WO2022167449A1

WO2022167449A1 - Method for minimization of contamination

Info

Publication number: WO2022167449A1
Application number: PCT/EP2022/052405
Authority: WO
Inventors: Alec WRIGHT; Eduardo Jose GARCIA GARCIA; Grzegorz Aleksander PILATOWICZ; Simon Dodd; David Steven HUNT
Original assignee: Jt International Sa
Priority date: 2021-02-02
Filing date: 2022-02-02
Publication date: 2022-08-11
Also published as: EP4287859A1

Abstract

The invention relates to a method for operating an aerosol generating device comprising: - an aerosol generating unit adapted to transform an aerosolisable liquid into aerosol comprising a micro electro-mechanical system (MEMS) comprising a microfluidic die and, - at least one exchangeable liquid cartridge in fluid connection to the aerosol generating unit. The method is characterized by operating the micro electro-mechanical system with a control unit, which operates a cleaning operation of the microfluidic die. The liquid contained in the die is aerosolized and ejected from the die with a cleaning unit comprising means for cleaning the die.

Description

Method for minimization of contamination

Description

The present invention is directed to a method for operating a micro electro-mechanical system with a control unit of an aerosol generating device and in particular to the aerosol generating device comprising an aerosol generating unit and at least one exchangeable cartridge.

Many kinds of the electronic smoking devices are available at the market. See, for example, the microfluidic vaporizer set forth in the prior art described in US10172388B2. Another example could be a hand-held vaporizer apparatus described in US20180199627A1. These all simulate the feeling or experience of smoking tobacco with a traditional cigarette by generating liquid to a vapor that cools and condenses to form an aerosol. This aerosol is than inhaled by the user. The invention is especially directed to a MEMS (micro electro mechanical system) style device. In the state of the art the MEMS devices are used to control a die which produces the vapor. The die is located within the device and is in connection to a capsule including vaporizing liquid. The vaporizing liquid often includes flavor enhancers or additives which change the traditional tobacco taste. Due to this, after changing or removing the cartridge a residual liquid remains in the fluid path and/or the vapor generating unit, which may mix with new liquid and/or may not. In this situation the residual liquid is undesired because it causes an unpleasant taste during the few first puffs and contaminates the fluid path and/or the vapor generating unit.

It is therefore an object of the invention to provide a method and an aerosol generating device that removes the undesired residual liquid out of the fluid path and/or the vapor generating unit. Preferably the device may remove the undesired liquid especially after exchange or removing of the capsule out of the aerosol generating device.

The above-mentioned requirement is met by the object of claim 1. Preferred embodiments are objects of the dependent claims.

The afore mentioned problems are solved by a method for operating an aerosol generating device comprising an aerosol generating unit and at least one exchangeable liquid cartridge, which is in fluid connection to the aerosol generating device. The aerosol generating unit is adapted to transform an aerosolisable liquid into aerosol comprising a micro electromechanical system (MEMS) and comprises a microfluidic die. The method is characterized by operating a micro electro-mechanical system with a control unit, which operates a cleaning operation of a microfluidic die, wherein a liquid contained in the die is aerosolized and ejected from the die with a cleaning unit comprising means for cleaning the die.

Preferably the microfluidic die comprised in MEMS is electrically and electronically connected to the control unit which sends and receives signals. Preferably the signals comprise relevant information for calculating the operating steps which are executed by MEMS. Also preferably MEMS operates the cleaning unit via signals. In case of contamination of the liquid paths and/or the aerosol generating unit with an unwanted residual liquid, the control unit sends MEMS signals which comprise information to give an instruction to the cleaning unit. After receiving the signals in the cleaning unit, a cleaning operation is preferably implemented. The cleaning operation is preferably executed with cleaning means. In a preferred embodiment the cleaning means comprise a cover or closing plate.

Preferably the closing plate is arrangeable in an open or closed position and is operated by a MEMS. The cover can be configured to be moved between an open position and a closed position of the aerosol channel during the cleaning operation. Additionally or alternatively, the cleaning means comprise an absorbing material configured to collect the aerosolized liquid ejected from the die.

The absorbing material is preferably attached to the cover or closing plate. It is conceivable that the cleaning operation purges residues out of the device along the channel in which the cleaning means are arranged. Preferably, if the cleaning means comprise a cover and or closing plate, the channel can be closed or opened towards the environment of the device upon actuating the cover and or closing plate.

Further it is conceivable that residues are purged into the absorbing material if the cover and or closing plate is in a closed position during a cleaning operation. Alternatively, it is conceivable that residues are purged into the environment of the device if the cover and or closing plate is in an open position during a cleaning operation.

In case of changing or disconnecting the cartridge from the aerosol generating device, this cartridge exchange or disconnecting operation may activate and perform a certain number of short firing “dummy” puffs. The “dummy” puffs ensure the removal of the residual liquid in the liquid paths and/or the aerosol generating unit, in particular in the die. The removed liquid is preferably aerosolized and not inhaled by the user. It is particularly advantageous to remove the residual liquid for preventing the unpleasant taste or clogging of the paths and/or other components of the aerosol generating device which are in contact with the aerosolizable liquids.

Dummy puffy are preferably understood as short (material) blasts which purge the residues of material and/or liquid and/or gas out of the die. Preferably the dummy puffs thereby eject the residues and/or liquid at least partially along the aerosol channel by the blast catching the residues and thereby preferably purging them out of the smoking device, or onto the absorbing material.

Preferably the number of maximal “dummy” puffs per full capacity of an internal electrical supply source is impacted depending on the number of times the cartridge is changed. Furthermore, a small fraction of energy in the internal electrical supply source is preferably reserved in the internal electrical supply source for the use case when the cartridge is replaced on the aerosol generating device with fully discharged internal electrical support source. Preferably an energy management system of the aerosol generating device do not allow the user to discharge the internal electrical supply source fully. In this case a sufficient fraction of the energy is always reserved for the cleaning operation.

According to another embodiment, the method is characterized by delaying the cleaning operation, wherein the cleaning operation is practicable only when the aerosol generating device is charged to an external electrical supply source. In case of charging to the external supply source, it is possible to delay the cleaning operation. It is conceivable that the control unit or MEMS sends a signal for requesting the charging state. Preferably the aerosol generating device comprises a charge-control unit which can receive the signal for requesting the charging state and send an answer. The answer could be positive, if the aerosol generating device is charging to the external electrical supply source and/or an internal electrical supply source has a low level. Preferably the cleaning operation is not initiated, if the answer is positive. Alternatively, it is possible that the answer is negative, if the aerosol generating device is charging to the external electrical supply source and/or an internal electrical supply source has a low level. In this case, it is possible that the cleaning operation is delayed, if the answer is negative.

This operating step prevents the removal of the liquid if the device is uncharged. In this case the user could be prompted to connect the aerosol generating device to a charger to perform the cleaning operation. The energy needed for firing the “dummy” puffs is then provided by the charger, therefore it does not impact the actual amount of energy stored in the internal electrical supply source.

According to another embodiment, the method is characterized by operating the cleaning operation after the liquid cartridge is disconnected from the aerosol generating unit, wherein the control unit receives a disconnecting signal from a detector comprised in the micro electro-mechanical system. Alternatively the detector is associated to the micro-electro- mechanical system.

Preferably MEMS comprises a detector which sends disconnecting or connecting signals to the control unit. The cleaning operation preferably starts after receiving the disconnecting or connecting signal from the detector. This prevents the cleaning operation from being started by mistake while the aerosol generating device is still in use with the old cartridge, for example. Nevertheless, starting the cleaning operation by the disconnecting or connecting signal is advantageous for the user because they do not have to worry about cleaning the aerosol generating device. The cleaning operation preferably starts automatically. This implementation is very efficient because it ensures that the user is never exposed to unpleasant vaping experience caused by contamination.

According to another embodiment, the method is characterized by operating the cleaning operation, wherein a second cartridge is connected to aerosol generating unit, wherein the control unit receives a connecting signal from the detector. In this embodiment, the cleaning operation could start after changing or removing of at least one liquid cartridge from the aerosol generating device. During removing of at least one cartridge, the connecting or disconnecting signal is preferably sent from at least one detector to the control unit. Preferably after receiving the disconnecting signal, the cleaning operation starts. It is conceivable that two disconnecting or connecting signals from both cartridges are necessary for operating the cleaning operation. This is in particular advantageous, if both cartridges are used for a mixed flavor or for a longer vaping experience.

In a preferred embodiment, the aerosol generating device comprises a second liquid cartridge which comprises a cleaning liquid. In this case, the cleaning operation preferably starts, if the control unit receives a connecting or disconnecting signal from at least one detector. It is possible that the connecting signal from the cleaning cartridge and the disconnecting signal from the liquid cartridge are necessary for starting the cleaning operation. In this case, the probability of an incorrect start of the cleaning operation is very low because the user has to actively insert the cleaning cartridge and/or disconnect the liquid cartridge from the aerosol generating device to start the cleaning operation.

According to another embodiment, the method is characterized by receiving a cleaning signal for operating the cleaning operation by a user’s action on the aerosol generating device.

It is possible that the aerosol generating device additionally or alternatively further comprises a communication means and/or at least one button to generate command and/or feedback signals. Alternatively or additionally the aerosol generating device preferably gives an acoustic signal to the user. In this case the cleaning operation preferably starts only if the user pushes the button after being advised to activate the cleaning operation. The detection of the removal of at least one cartridge as well as insertion of the new liquid cartridge is preferably not necessary. The communication means could comprise at least one display or light emitting diode. It is conceivable that the user can start the cleaning operation by a gesture, touchpad or other input means.

According to another embodiment, the method is characterized in that the cleaning operation comprises a pulsating operation, wherein the micro electro-mechanical system generates a number of aerosol cycles. Preferably the pulsating operation is operated by the aerosol generating unit. In this case the aerosol generating device preferably comprises an attachment which is configured to apply an internal pressure on at least one cartridge so as to pulsate the liquid to the aerosol generating unit. Preferably the pulsating operation also operates the die which in this embodiment requires a priming. Alternatively or additionally the pulsating is a part of the usual operation during the vaping experience. In particular the liquid is preferably ejected from the liquid path and/or aerosol generating unit, in particular from the die, during the pulsation operation.

According to another embodiment, the method is characterized by collecting the aerosolized and ejected liquid from the die on an absorbing material.

Preferably the absorbing material is positioned immediately downstream or above the aerosol generating unit, in particular immediately downstream or above the die. The ejected aerosolized liquid from the liquid path and/or the aerosol generating unit is preferably collected on the absorbing material. In this case, the cleaning operation can be operated fully automated. It is not necessary to hold the aerosol generating device in the hand during the cleaning operation. The user can leave the aerosol generating device inside his bag or pocket for a longer period of time without worrying about the cleaning of his device.

According to another embodiment, the method is characterized in that the absorbing material is positioned on the second exchangeable cartridge replacing the first exchangeable cartridge.

According to another embodiment, the method is characterized by absorbing the aerosolized and ejected liquid from the die with the absorbing material, wherein the absorbing material is positioned on a cover of an aerosol channel of the exchangeable cartridge.

Preferably the aerosol channel is in fluid connection to the aerosol generating unit. It is possible that the aerosol channel leads the aerosolized liquid from at least one cartridge to the mouthpiece. Preferably the cover is moveably hinged on a seat of the aerosol generating device. In this case it is possible that the aerosol generating device comprises means for moving the cover which can receive signals from the control unit and/or MEMS. It is possible that the control unit sends signals to the means for moving the cover during the cleaning operation. Preferably dependent on the received signal, the means for moving the cover open or close the aerosol channel during the cleaning operation. It is particularly advantageous to close the aerosol channel during the cleaning operation because the ejected aerosolized liquid can be collected on the absorbing material arranged on at least one surface of the cover.

According to another embodiment, the method is characterized by ejecting the aerosolized liquid from the die to ambient air. Alternatively the cover of the aerosol channel is preferably opened during the cleaning operation. In this case the absorbing material is preferably not needed because the aerosolized liquid is ejected to the ambient air.

According to another embodiment, the method is characterized by supplying a cleaning liquid from a cleaning cartridge to the microfluidic die and ejecting the cleaning fluid therefrom, wherein the cleaning cartridge is mounted on the aerosol generating unit. The cleaning liquid preferably comprises a neutral fluid such as deionised water. It is also possible that the cleaning cartridge comprises a neutral gas under pressure which can be ejected during the cleaning operation.

The objective is also reached by an aerosol generating device comprising an aerosol generating unit and at least one exchangeable liquid cartridge which is in fluid connection to the aerosol generating unit. The aerosol generating unit is adapted to transform an aerosolisable liquid into aerosol comprising a micro electro-mechanical system (MEMS) comprising a microfluidic die. The aerosol generating device is characterized in that the micro electro-mechanical system comprises a control unit for operating a cleaning operation of the microfluidic die and a cleaning unit comprising means for cleaning the die.

Preferably the aerosol generating device comprises a mouthpiece. The mouthpiece could be integrated into the exchangeable liquid cartridge or be a fixed component of the aerosol generating device being attached on top of the device. It is also conceivable that the aerosol generating device and/or the cartridge comprise at least two parts which create the mouthpiece by merging. Furthermore the aerosol generating device preferably comprises at least one duct or liquid channel for channeling the liquid arranged inside the cartridge to the aerosol generating unit. Preferably at least one cartridge is arranged in the aerosol generating device at least partially. Also preferably a second cartridge is in fluid connection to the aerosol generating unit via at least one duct or liquid channel. It is conceivable that the liquid is projected from the cartridge to the aerosol generating unit through the duct or liquid channel. In this case the aerosol generating device preferably comprise an urging means, which urges the liquid from the cartridge to the aerosol generating unit. The urging means could preferably create a flow path of a flowable and aerosolisable medium, especially a liquid. Preferably the urging means is given by the design of the exchangeable liquid cartridge.

According to another embodiment, the aerosol generating device is characterized in that the aerosol generating device further comprises a detector for detecting a mechanical and/or fluid connectivity between the aerosol generating unit and at least one exchangeable liquid cartridge.

Preferably MEMS comprises a detector which sends disconnecting and/or connecting signals to the control unit. Preferably the detector detects the removal and/or insertion of at least one cartridge. It is possible that the aerosol generating device comprises a second detector for detecting the connectivity between the aerosol generating unit and the second cartridge. Such a detector may be a magnetic position sensor, photoelectric, inductive, capacitive, ultrasonic or optical sensor.

According to another embodiment, the aerosol generating device is characterized in that the aerosol generating device further comprises a second liquid cartridge and/or a cleaning cartridge comprising a cleaning fluid, preferably deionised water.

It is conceivable that the cleaning fluid can be any fluid which is suitable to purge residues from the die. The fluid could be in gaseous and/or liquid state. The usage of heated or cooled fluids could also be advantageous.

Residues are preferably purged from the die by flushing the cleaning fluid through the die. In a preferred embodiment the flushing occurs with a certain pressure to blow the residues out of the die. Thus the residues preferably stick to the cleaning fluid and are released from the die.

The cleaning fluid with the residues is afterwards preferably released into the environment and/or the absorbent material. Thereby the residues are either released from the device, or stuck to the absorbent material. It is conceivable that a cleaning method with an absorbent pad requires temporarily change of the absorbent pad, if the maximum absorbing amount of residues is reached.

Preferably the aerosol generating device is in fluid connection to a first and a second exchangeable liquid cartridge. It is possible that both cartridges comprise the aerosolisable liquid. The liquid in each cartridge could be similar or different to each other. The liquid may differ as to their flavor and/or other additives. In case of different liquids, it is possible that the user can decide which cartridge he would like to vape. It is advantageous in view of duration of the vaping experience because the liquids in the first and the second cartridges are useable in a row. The cleaning operation is preferably operable when the first cartridge is empty. It is also conceivable to use both cartridges simultaneously. In this case the cleaning operation is preferably operable before or after insertion of both cartridges. It is also conceivable that the first or the second liquid cartridge comprises cleaning liquid. In this case the second liquid cartridge is preferably only useful for the cleaning operation. The cartridge(s) may comprise a cleaning liquid and the aerosolisable liquid in separate compartments.

According to another embodiment, the aerosol generating device is characterized in that the aerosol generating unit and/or the liquid cartridge further comprises an absorbing material. Preferably the absorbent material comprises cotton, felt or wool.

According to another embodiment, the aerosol generating device is characterized in that the absorbing material is applied on one surface of a cover, which seals an aerosol channel of the aerosol generating device from the ambient air. Preferably the absorbent material is formed as a sheet with a thickness in a range of from 0.1 mm to 3 mm. It is conceivable that the absorbent material is glued, pressed or sprayed to the cover of the aerosol channel.

Further advantages, objectives and features of the present invention will be described, by way of example only, in the following description with reference to the appended figures. In the figures, like components in different embodiments can exhibit the same reference symbols.

The figures show:

Fig. 1 a partial schematic sectional view of an aerosol generating device with a movable cover in a closed position;

Fig. 1a an enlarged schematic sectional view of a movable cover;

Fig. 2 a partial schematic sectional view of an aerosol generating device with a movable cover in an opened position; Fig. 3 a schematic view of an aerosol generating device according to one embodiment of the invention;

Fig. 4 a schematic three-dimensional view of an aerosol generating unit;

Fig. 5 a flow chart of a method for minimization of contamination;

Fig. 6 a schematic view of fluidic and electronic/electric connections between the components of an aerosol generating device.

Figure 1 shows a partial schematic sectional view of an aerosol generating device 24 with a movable cover 13 in a closed position. This aerosol generating device 24 comprises at least one exchangeable liquid cartridge 1, a mouthpiece 3 and an aerosol generating unit 5. The shown liquid cartridge 1 comprises an inner volume 2 in which an aerosolisable liquid, preferably an e-liquid, is comprised. The shown aerosol generating unit 5 comprises a micro electro-mechanical system (MEMS) 20 (shown in fig. 4) and a microfluidic die 7a. The liquid cartridge 1 is connected to the aerosol generating unit 5 by at least one liquid channel 7, preferably two liquid channels 7 which are arranged parallel to each other. The liquid channel 7 creates a liquid path 6 which provides a fluid connection between the liquid cartridge 1 and the aerosol generating unit 5. Preferably, the liquid channel 7 leads the liquid from the liquid cartridge 1 to a filter chamber 8 which is connected to the aerosol generating unit 5 via a further channel or tube (not shown). Also preferably the liquid is drawn from the liquid cartridge 1 and the liquid channel 7 to the aerosol generating unit 5 by capillary force. The microfluidic die 7a is preferably ejecting the aerosol parallel or perpendicular to the aerosol channel 4.

The aerosol generating device 24 further comprises an aerosol channel 4 which is attached between the aerosol generating unit 5 and the mouthpiece 3. When the aerosol generating device 24 is not in use, the aerosol channel 4 is closed at least in part with a cover 10.

Figure 1a shows an enlarged schematic sectional view of a movable cover 10. Preferably, the cover 10 is formed as a closing plate 11 which keeps the aerosol generating unit 5 clean and protected from external influences such as dirt. The cover 10 further comprises a seat 12 a hinge 13 which keeps the closing plate 11 movable. It is conceivable that the hinge 13 also comprises at least one spring 17 and is operated by an electrical closing mechanism (not shown) which is in electrical/electronical connection to MEMS 20. Preferably the cover 10 in the closed position touches at least in part the seat 12 which is formed as a protrusion. It is conceivable that the cover 10 further comprises an absorbent material 16. This could be attached on an upper 15 and/or lower 14 face of the closing plate 11. Preferably the absorbent material comprises cellulose pulp or other fibrous materials.

In one embodiment of the invention the closed cover 10 in the aerosol channel 4 is used for absorbing the last liquid comprised in the liquid path 6 or the liquid channel 7 after changing the liquid cartridge 1. In this case the MEMS 20 operates the aerosol generating unit 5 to perform a dummy puff, wherein the cover 10 is closed and the absorbent material 16 absorbs the ejected aerosol. The procedure is described in detail in figures 5 and 6.

Figure 2 shows a partial schematic sectional view of the aerosol generating device 24, as already shown in figure 1 , with the movable cover 10 in an opened position. The cover 10 comprising the closing plate 11 is opened, whereby the aerosol which is generated in the aerosol generating unit 5 can escape along the aerosol channel 4 out of the mouthpiece 3. Preferably the MEMS 20 operates the cover 10 to open, if at least one cartridge 1 is changed or by a user’s action on the aerosol generating device 24. It is conceivable that the MEMS 20 receives a disconnecting signal from a detector (not shown here). The opened cover 10 in the aerosol channel 4 is preferably used for ejecting the old liquid comprised in the liquid path 6, the liquid channel 7 or the aerosol generating unit 5 after changing the liquid cartridge 1 to the ambient air. In this case MEMS 20 operates the aerosol generating unit 5 to perform a dummy puff, wherein the cover 10 is opened and the generated aerosol is ejected to the ambient air. The procedure is described in detail in figures 5 and 6.

Figure 3 shows a schematic view of an aerosol generating device 24 according to one embodiment of the invention. The shown aerosol generating device 24 comprises a mouthpiece 3, an aerosol generating unit 5, two liquid cartridges 1 with inner volume 2, a battery 18 and a main printed circuit board 19. Preferably all components are in fluidic and/or electrical connection to each other. The main printed circuit board 19 is preferably connected to at least one further printed circuit board 21 (shown in fig. 4). For an energy supply, the battery 18 is connected at least to the main printed circuit board 19 and the aerosol generating unit 5. Preferably the aerosol generating unit 5 is a part of MEMS 20 as shown in figure 4 and is operated by at least one printed circuit board 21.

Figure 4 shows a schematic three-dimensional view of an aerosol generating unit 5.

Preferably the aerosol generating device 5 comprises at least one printed circuit board 21. On its at least one surface electrical and electronical components are mounted for operating different operations, in particular the cleaning operation. The printed circuit board 21 is preferably mounted to the main printed circuit board 19 via electrical connections and comprises inlet ports 23 for leading the liquid from the liquid cartridge to the upper surface of MEMS 20. Preferably MEMS 20 further comprises a heating component (not shown here) which transforms the liquid from the inlet port 23 to an aerosol. The heating component may take the form of a heating resistor. It is conceivable to apply a heater control circuit to the aerosol generating unit 5 (not shown here). Preferably the aerosol generating unit 5 or the heating component heats the liquid rapidly on the upper surface of MEMS 22 until the liquid starts to boil and forms an aerosol bubble. Preferably the bubble comprises a phase change of the liquid and the air which is trapped in the liquid. The aerosol is preferably pushed out and flow into the aerosol channel 4 (shown in figure 1) due to a force provided by the volume differences of the liquid and the air. The bubble grows as it is heated until it is preferably large enough that it forces liquid droplets to flow out through the die 7a (shown in figure 1). Preferably the bubble might escape when the droplets are ejected creating thereby a vacuum. The vacuum preferably causes more liquid to be drawn into the aerosol generating unit 5 from the liquid channel 7 (shown in figure 1) or inlet ports 23. Preferably the liquid is drawn from the liquid channel 7 and/or the inlet ports 23 into MEMS 20 by capillary action. Also preferably the capillary action allows fluid communication between the liquid channel 7 and/or the inlet port 23 and the aerosol generating unit 5.

The aerosol flows substantially in a direction towards the mouthpiece 3 (shown in figure 2) when the user draws upon the mouthpiece 3. The inlet ports 23 connect the aerosol generating unit 5 to the mouthpiece 3 for the passage of liquid through the aerosol generating unit 5. The shown embodiment of the aerosol generating unit comprises two inlet ports 23. It is conceivable that MEMS 20 is connected and/or mounted to the main printed circuit board 19 and the mouthpiece 3 (shown in figure 3). But it is also conceivable to mount MEMS 20 to a separate printed circuit board (not shown here).

Preferably the upper surface of MEMS 22 is parallel to the microfluidic die 7a which is shown in figure 1. It is conceivable that the surface 22 may be offset to the die 7a (not shown here). In this case the aerosol may flow sideways along the heating component and/or the upper surface of MEMS 22 and then being ejected or pulled up from the die 7a. Alternatively the aerosol may flow directly into the aerosol channel 4 in a direction towards the mouthpiece 3 (shown in figure 1). Alternatively, the die 7a and the surface of MEMS 22 may align direction one above the other. Figure 5 shows a flow chart of a method for minimization of contamination. The basic steps for cleaning operation are: operating MEMS with a control unit 100; operating the cleaning operation 101; aerosolizing of the liquid 102 and ejecting the aerosolized liquid 103. These steps are preferably always executed in view of different embodiments of the method. Some examples of the method are described below.

It is conceivable that the method further comprises receiving the disconnecting or connecting signals from a detector 28 step 106, wherein the detector 28 preferably is mounted in the aerosol generating device 24, preferably in a mounting port for the exchangeable liquid cartridge 1. It is also conceivable that the method comprises receiving the disconnecting or connecting signal from at least one cartridge step 105, before the basic steps 100 - 103 are executed. Alternatively the steps 105 and 106 could be operated after each other or simultaneously (not shown here) before the basic steps 100 - 103, wherein disconnecting and/or connecting signals are send from the cartridge 1 and the aerosol generating device 24. In this case, it is possible to send disconnecting or connecting signals from two detectors, wherein a first cartridge 1 is detected with a first detector 28 mounted in the device 24 and the second cartridge, e.g. the cleaning cartridge 1a, is detected with a second detector 28 mounted in the second cartridge 1. Preferably the detector 28 mounted in the cartridge 1 , 1a is connectable with MEMS 20 and/or control unit 25.

Alternatively or additionally, the receiving of a cleaning signal by a user step 107 is preferably executed before the basic steps 100 - 103. Also alternatively or additionally, the delaying of the cleaning operation step 104 is preferably executable. In this case the cleaning operation is preferably not operable because of a low level of an energy supply source, e.g., of the battery 18. It is possible to add the supplying of a cleaning liquid from the cleaning cartridge step 110 to the method. In this case the mandatory prerequisite is a second cartridge 1 with a cleaning liquid inside.

There are at least two possibilities for the last step of the method. In the first embodiment, the ejected aerosolized liquid is collected or absorbed 108 on the absorbent material 16 arranged on the cover 10. It is also possible in the second embodiment to eject the aerosolized liquid to the ambient air 109. In this case the cover 10 for the aerosol channel 4 could be not necessarily required. Figure 6 shows a schematic view of fluidic and electronic/electric connections between the components of an aerosol generating device 24. Preferably the exchangeable liquid cartridge 1 or the cleaning cartridge 1a is in fluid connection 29 to at least one detector 28 for detecting the connectivity between the aerosol generating device 24 and the cartridge 1, 1a. Also preferably the detector 28 is in electrical and/or electronical connection 30 to the control unit 25. The control unit 25 is further preferably electrically connected 30 to the cleaning unit 26 which comprise cleaning means 27 for operating the cleaning operation. Preferably the cleaning unit 26 is in electrical and/or electronical connection 30 and the cleaning means 27 in fluidic connection 29 to the microfluidic die 7a. The microfluidic die 7a is further preferably in fluidic connection 29 to the mouthpiece 3 via aerosol channel 4. It is conceivable that MEMS comprise at least one detector 28 for detecting the connectivity between the aerosol generating device 24 and the cartridge 1, 1a, the cleaning unit 26 comprising cleaning means 27, the control unit 25 and the microfluidic die 7a.

The applicant reserves his right to claim all features disclosed in the application document as being an essential feature of the invention, as long as they are new, individually or in combination, in view of the prior art. Furthermore, it is noted that in the figures features are described, which can be advantageous individually. Someone skilled in the art will directly recognize that a specific feature being disclosed in a figure can be advantageous also without the adoption of further features from this figure. Furthermore, someone skilled in the art will recognize that advantages can evolve from a combination of diverse features being disclosed in one or various figures.

List of reference symbols exchangeable liquid cartridge inner volume mouthpiece aerosol channel aerosol generating unit liquid path liquid channel a microfluidic die filter chamber filter 0 cover 1 closing plate 2 seat 3 hinge 4 lower face of the closing plate 5 upper face of the closing plate 6 absorbent material 7 spring 8 battery 9 main printed circuit board 0 micro electro-mechanical system (MEMS) 1 printed circuit board 2 upper surface of MEMS 3 inlet port 4 aerosol generating device 5 control unit 6 cleaning unit 7 cleaning means 8 detector for detecting the connectivity between aerosol generating device and cartridge 9 fluid connection 0 electrical/electronical connection 00 operating MEMS with a control unit 01 operating cleaning operation aerosolizing of the liquid ejecting the aerosolized liquid delaying the cleaning operation receiving disconnecting/connecting signal from a detector receiving disconnecting/connecting signal from at least one cartridge receiving a cleaning signal by user collecting/absorbing the aerosolized and ejected liquid ejecting aerosolized liquid to the ambient air supplying a cleaning liquid from the cleaning cartridge

Claims

Claims A method for operating (100) an aerosol generating device (24) comprising : an aerosol generating unit (5) adapted to transform an aerosolisable liquid into aerosol comprising a micro electro-mechanical system (MEMS) (20) comprising a microfluidic die (7a) and, at least one exchangeable liquid cartridge (1) in fluid connection to the aerosol generating unit (5), characterized by operating (100) the micro electro-mechanical system (20) with a control unit (25), which operates (101) a cleaning operation of the microfluidic die (7a), wherein the liquid contained in the die (7a) is aerosolized (102) and ejected (103) from the die (7a) with a cleaning unit (26) comprising means (27) for cleaning the die (7a), wherein the cleaning means (27) comprise a closing plate (11) for opening or closing an aerosol channel (4) through which the liquid is ejected and/or an absorbing material (16) configured to collect the aerosolized liquid ejected from the die (7a). The method according to claim 1, characterized by delaying (104) the cleaning operation, wherein the cleaning operation is practicable only when the aerosol generating device (24) is charged to an external electrical supply source. The method according to any one of the preceding claims, characterized by operating (101) the cleaning operation after the liquid cartridge (1) is disconnected from the aerosol generating unit (5), wherein the control unit (25) receives (105) a disconnecting signal from a detector (28) comprised in the micro electro-mechanical system (20). The method according to claim 3, characterized by operating (101) the cleaning operation, wherein a second cartridge (1) is connected to aerosol generating unit (5), wherein the control unit (25) receives (106) a connecting signal from the detector (28). The method according to any one of the preceding claims, characterized by receiving (107) a cleaning signal for operating the cleaning operation by a user’s action on the aerosol generating device (24). The method according to any one of the preceding claims, characterized in that the cleaning operation comprises a pulsating operation, wherein the micro electromechanical system (20) generates a number of aerosol cycles. The method according to any one of the preceding claims, characterized by collecting (108) the aerosolized and ejected liquid from the die (7a) on an absorbing material (16). The method according to claim 7, characterized in that the absorbing material (16) is positioned on the second exchangeable cartridge (1) replacing the first exchangeable cartridge (1). The method according to claims 7 or 8, characterized by absorbing (108) the aerosolized and ejected liquid from the die (7a) with the absorbing material (16), wherein the absorbing material (16) is positioned on a cover (10) of an aerosol channel (4) of the exchangeable cartridge (1). The method according to any one of claims 1 to 6, characterized by ejecting (109) the aerosolized liquid from the die (7a) to ambient air. 19 The method according to any one of the preceding claims, characterized by supplying (110) a cleaning liquid from a cleaning cartridge (1a) to the microfluidic die (7a) and ejecting (103) the cleaning liquid therefrom, wherein the cleaning cartridge (1a) is mounted on the aerosol generating unit (5). An aerosol generating device (24) comprising an aerosol generating unit (5) and at least one exchangeable liquid cartridge (1), which is in fluid connection to the aerosol generating unit (5), wherein the aerosol generating unit (5) is adapted to transform an aerosolisable liquid into aerosol comprising a micro electro-mechanical system (MEMS) (20) comprising a microfluidic die (7a), characterized in that the micro electro-mechanical system (20) comprises a control unit (25) for operating a cleaning operation of the microfluidic die (7a) and a cleaning unit (26) comprising means (27) for cleaning the die (7a). The aerosol generating device (24) according to claim 12, characterized in that the control unit (25) comprises a detector (28) for detecting a mechanical and/or fluid connectivity between the aerosol generating unit (5) and at least one exchangeable liquid cartridge (1). The aerosol generating device (24) according to claim 12 or 13, characterized in that the aerosol generating device (24) further comprises a second liquid cartridge (1) and/or a cleaning cartridge (1a) comprising a cleaning fluid, preferably deionised water. The aerosol generating device (24) according to any one of claims 12 to 14, characterized in that the aerosol generating unit (5) and/or the liquid cartridge (1, 1a) further comprises an absorbing material (16).