[ Technical Field]

The present invention relates to an aerosol generation unit . In particular, the present invention relates to mechanisms for generating an aerosol in the speci fic context of aerosol generation devices , such as inhalers , e-cigarettes , and the like .

[Background]

By vapori zing a liquid an aerosol is generated which can then be inhaled by a user . Vapori zation arrangements are typically provided in electronic cigarettes , electronic air fresheners or medical inhalers . The heating engines of conventional vapori zation arrangements are based on resistive heating in which electrical energy is delivered to a resistive heater such as a coil or thin wire . The resistive heater converts the electrical energy into heat which is then trans ferred to a wick attached to the resistive heater . Typical material s for wicks include ceramic, such as Zeolite Y, and cotton . Resistive heaters are typically made from nichrome with a resistance of the order of 1 Q . The wick is heated to a high temperature , typically in the range of 150 to 250 ° C, such that liquid, which is absorbed by the wick, is vapori zed . The generated aerosol can then be inhaled by a user, for example , by "puf fing" that is by generating an air flow by sucking . The air flow may also be generated by natural convection or with a fan .

However, such wick-based vapori zation arrangements may have several problems . Vapori zation arrangements using a cotton wick run the risk of "dry puf fs" , which occur when there i s not enough liquid available such that the resistive heater is trans ferring heat to a dry wick . In this case , the wick can reach very high temperatures and emit potentially increased quantities of undesired components . Furthermore , "dry puf fs" may be an unpleasant experience for the user inhaling these substances .

Another problem of wick-based vapori zation arrangements is that a residue in the liquid can clog the ceramic or cotton wick, thereby hindering the flow of liquid . The type of residue depends on the formulation of the liquid . A typical residue is tobacco . The residue may get burned after a limited time period, thereby generating smoke which again leads to an unpleasant experience for the user . Furthermore , the wick may be damaged such that the wick-based vapori zation arrangement cannot be used anymore .

Furthermore , the inhalation experience of the user strongly depends on the water content of the liquid to be vapori zed . Conventional liquids used in electronic cigarettes may be strongly hygroscopic . Due to moisture in the air, liquid, which may, for example , be stored in sealed containers on a shel f , may absorb water with time even under good storage conditions and with the best barrier properties of the packaging solutions . Therefore , the longer the liquid containers rests on the shel f and the higher the ambient temperature , the more water content is found in the liquid . Hence , the liquid becomes diluted with water which results in an inferior taste experienced by the user inhaling the aerosol generated by vapori zing said diluted liquid .

[ Summary]

The novel vapori zation arrangement proposed in the present disclosure is based on the ohmic heating principle . Ohmic heating means that an electric current flows directly through a liquid in a vapori zation volume . In this case , the liquid can be considered as an electric resistance in which heat is directly generated . The heating of the liquid is therefore achieved more ef ficiently compared to conventional approaches using resistive heaters .

Furthermore , the proposed vapori zation arrangement does not require any wicking material . I f there is no liquid in the vapori zation volume , there is no flow of electric current and the problem of "dry puf fs" can be eliminated . Additionally, this wickless design may also eliminate the problem o f clogging of the wick . Hence , user experience and safety of the vapori zation arrangement may be improved .

By omitting the resistive heater and wick, the number of components of the proposed vapori zation arrangement may be reduced compared to conventional implementations , which may result in a reduction of the overall manufacturing costs and in a longer service li fe of the vapori zation arrangement .

Furthermore , the ohmic heating method may of fer the possibility to continuously monitor the liquid resistance , which is directly related to the temperature of the liquid and indirectly to the heating dynamics . This way, it may be possible to determine the water content of the liquid . By applying such liquid resistance monitoring the present invention may of fer a method to prevent the user from inhaling aerosol generated by vapori zing liquids with inacceptable water content . Thus , the proposed vapori zation arrangement based on the ohmic heating principle may of fer quality control means .

Moreover, agents may be added to the liquid in order to improve its electrical conductivity such that the liquid resistance is lowered . Hence , by monitoring the liquid resistance and comparing it to one or more reference values , it may be possible to detect whether or not the liquid is genuine . Thus , the proposed vapori zation arrangement based on the ohmic heating principle may of fer anti-counterfeit means .

One embodiment relates to a vapori zation arrangement for an inhaler and configured to generate an aerosol to be inhaled by a user comprising a vapori zation chamber comprising a pair of electrodes defining a vapori zation volume between the pair of electrodes , a de power source arranged to apply an electric de potential to the pair of electrodes to generate a de current flow between the two electrodes and liquid in the vapori zation volume , and an electric circuitry arranged to measure a current associated with the de current flow, determine a liquid resistance based on the electric de potential and the measured current , and control an operation of the vapori zation arrangement based on the liquid resistance .

[Brief description of the drawings ]

Embodiments of the present invention, which are presented for better understanding the inventive concepts , but which are not to be seen as limiting the invention, will now be described with reference to the figures in which : Fig . 1 shows a vapori zation arrangement according to an embodiment of the present invention;

Fig . 2A shows a vapori zation arrangement with a compact design according to an embodiment of the present invention;

Fig . 2B shows a vapori zation arrangement with a compact design further comprising a sediment trap according to an embodiment of the present invention;

Fig . 3 shows a vapori zation arrangement with a compact design further comprising a gauze and a recess structure for channeling the air flow according to an embodiment of the present invention;

Fig . 4 shows a vapori zation arrangement according to an embodiment of the present invention .

Fig . 5A shows from an angled point of view a pair of electrodes according to an embodiment of the present invention;

Fig . 5B shows from a side view a pair of electrodes according to an embodiment of the present invention;

Fig . 6 shows a circuit diagram compri sing a de power source , a current regulator and resistor given by a liquid in a vapori zation volume ; Fig . 7 shows a plot of the conductivity of the liquid with respect to the temperature of the liquid;

Fig . 8A shows a plot of the resistance of di f ferent formulations of the liquid with respect to time ;

Fig . 8B shows a plot of the temperature o f di f ferent formulations of the liquid with respect to time ;

Fig . 9 shows a plot of the conductivity of the liquid with respect to the concentration of NaCl in the liquid; and

Fig . 10 shows a flowchart representing the control logic of a vapori zation arrangement with quality control and anti-counterfeit means .

[ Detailed description]

The present invention shall now be described in conj unction with speci fic embodiments . The speci fic embodiments serve to provide the skilled person with a better understanding but are not intended to in any way restrict the scope of the invention, which is defined by the appended claims . In particular, the embodiments described independently throughout the description can be combined to form further embodiments to the extent that they are not mutually exclusive . Fig. 1 shows a vaporization arrangement 1 according to an embodiment of the invention in a cross-sectional view. The vaporization arrangement 1 is configured to generate an aerosol 2 to be inhaled by a user. The vaporization arrangement 1 comprises a vaporization chamber 3 comprising a pair of electrodes 4a, 4b. The pair of electrodes 4a, 4b define a vaporization volume 5 between them. A liquid is supplied to the vaporization chamber 3. A de power source 11, not shown in Fig. 1, is arranged to apply an electric de potential to the pair of electrodes 4a, 4b such that one electrode of the pair of electrodes 4a, 4b is positively charged while the other electrode is negatively charged. A de current flow is generated between the pair of electrodes 4a, 4b and passes through the liquid 8 in the vaporization volume 5. This way, the liquid 8 can be heated via ohmic heating to its boiling temperature to generate the aerosol 2. The vaporization arrangement 1 further comprises an electric circuitry arranged to measure a current associated with the de current flow, determine a liquid resistance based on the electric de potential and the measured current, and control an operation of the vaporization arrangement 1 based on the liquid resistance.

A liquid conduit 6 may be arranged to supply, from a liquid store 7, the liquid 8 to the vaporization chamber 3. A vapor conduit 9 may be arranged to discharge the aerosol 2, generated in the vaporization volume 5, from the vaporization chamber 3. The air flow 10, indicated by the arrow in Fig. 1, illustrates the direction in which the aerosol 2 may be discharged to then be inhaled by a user.

The vaporization arrangement 1 may be provided in an electronic cigarette, an electronic air freshener or a medical inhaler. Depending on the application, the vaporization arrangement 1 may be adapted in its size, shape and capacity to fulfill the given requirements such as, for example, requirements related to weight, size, shape, operational safety, aerosol production rate, or electric or liquid capacity.

The formulation of the liquid 8 may vary depending on the intended purpose. Typically, the formulation of the liquid 8 can be adapted to provide different flavors to the generated aerosol 2. For the application in electronic cigarettes, for example, the main ingredients of the liquid 8 are typically propylene glycol, glycerin, which serve as the solvent, and may further include various flavorings and, most often, nicotine in liquid form. For example, flavorings may contain menthol, sugars, esters, and pyrazines. The formulation of the liquid may contain acid. The formulation of the liquid 8 may contain additives that increase the conductivity of the liquid 8. An example for such an additive is sodium chloride, NaCl, which is widely used for cold vaporizers and inhalators. Based on measurements of typical formulations of the liquid 8 for the use in electronic cigarettes, wherein the formulations comprise 18 mg/ml nicotine diluted with 10 volume percent of ultrapure water and mixed with acid, the conductivity of the liquid 8 may be 63 pS/cm, 199 pS/cm or 962 pS/cm for formulations without NaCl, with 10 mg/ml NaCl or with 50 mg/ml NaCl, respectively.

The liquid store 7 may serve as a reservoir for the liquid 8. The liquid store 7 may be provided as an exchangeable capsule or pod, which a user can insert into the vaporization arrangement 1 in a detachable manner. For example, the user can attach a capsule to the vaporization arrangement 1 such that the liquid 8 therein can flow from it, through the liquid conduit 6 and into the vaporization chamber 3. Then, when the liquid 8 in the capsule is depleted, that is most of the liquid 8 therein has been vaporized, the user may detach the depleted capsule in order to insert a new one . The liquid store 7 may be connected to a secondary reservoir, not shown in Fig . 1 , which may serve as the exchangeable capsule or pod in this case . The liquid store 7 may be provided with a transparent enclosure such that the user may observe the fill level of the liquid 8 .

The liquid conduit 6 may connect the liquid store 7 with the vapori zation chamber 3 such that the liquid 8 can flow from the liquid store 7 to the vapori zation chamber 3 . The liquid conduit 6 may be provided as one or more rigid or flexible tubes or as one or more holes provided in an enclosure of the vapori zation chamber 3 . For example , a sidewall of a bottom section of the vapori zation chamber 3 may comprise a liquid inlet allowing the liquid 8 to flow into the vapori zation chamber 3 . For an exchangeable liquid store 7 the liquid conduit 6 may be provided with sealings , such as gaskets , that prevent leakage of the liquid 8 . The liquid conduit 6 may be provided with a valve which can be opened or closed to allow or prevent the flow of liquid 8 to the vapori zation chamber 3 . The valve may be a one-way valve that only allows the liquid 8 to flow in the direction of the vapori zation chamber 3 . The liquid conduit 6 may be provided with a filter to prevent pollutants from entering the vapori zation chamber 3 .

The vapori zation chamber 3 houses the pair of electrodes 4a , 4b . The liquid 8 may flow into the vapori zation chamber 3 where it may be exposed to the electric de potential in the vapori zation volume 5 between the pair of electrodes 4a, 4b . The pair of electrodes 4a, 4b may be metal based electrodes , such as electrodes made from stainless steel , copper, nickel or gold . In Fig . 1 , the pair of electrodes 4a, 4b is provided parallel to the flow direction of liquid 8 , such that the de electric potential is perpendicular to the flow direction . However, the pair of electrodes 4a, 4b may also be provided perpendicular to the flow direction of the liquid 8 , such that the de electric potential is ( approximately) parallel to the flow direction of the liquid 8 . In this case , the pair of electrodes 4a, 4b may be provided with holes or as a grating in order to allow the liquid 8 to enter, and the aerosol 2 to exit the vapori zation volume 5 . Such an embodiment will be exempli fied with reference to Figs . 2A and 2B and Figs . 3A and 3B .

The distance between the pair of electrodes 4a, 4b may be determined based on the required de electric potential to be applied and the electric power provided by the de power source 11 in order to ensure that the liquid 8 is heated and vapori zed suf ficiently quick . The smaller the distance between the pair of electrodes 4a, 4b is , the larger the applied de electric potential is at a given output power level of the de power source 11 , which may result in faster heating of the liquid 8 and thus in an increased amount o f aerosol 2 generated . Hence , a lower distance between the pair of electrodes 4a, 4b may result in a better heating ef ficiency . The distance between the pair of electrodes 4a, 4b may be arranged using an insulating spacer . The distance between the pair of electrodes 4a, 4b may preferably be 1 mm or less , and more preferably be 0 . 5mm or less . Further, the distance between the pair of electrodes 4a, 4b may preferably be 0 . 5 mm or less , and more preferably be 1 mm or less . Especially the latter options may provide advantages in relation to manufacturing costs .

The vapori zation chamber 3 may be provided with a gauze 16 in the direction of the vapor conduit 9 . In other words , the gauze 16 may be arranged above the pair of electrodes 4a, 4b . The gauze 16 may allow the generated aerosol 2 to pass through but prevent any liquid 8 which has not yet been vapori zed from exiting the vaporization volume 5 . This way, leakage of the liquid 8 into the vapor conduit 9 may be prevented, thereby ensuring that the user does not take in the liquid 8 directly .

Furthermore , the vapori zation chamber 3 may be provided with a valve in the direction of the vapor conduit 9 . The valve can be opened or closed to allow or prevent the aerosol 2 from flowing into the vapor conduit 9 . This way, the discharge of aerosol 2 may be immediately disabled . The valve may be a one-way valve that only allows the aerosol 2 to flow in the direction of the vapor conduit 9 .

Moreover, the vapori zation chamber 3 may be provided with one or more sediment traps that can hold a residue after heating . The sediments traps may serve as reservoirs in which particles suspended in the liquid 8 can accumulate . The type of residue depends on the formulation of the liquid 8 . A typical residue is , for example , tobacco . The sediment traps may be provided as recesses and may be arranged within the vapori zation chamber 3 in the direction of the liquid conduit 6 . The sediments traps may prevent residue from depositing within the vapori zation volume 5 where it may negatively af fect the ohmic heating process by partially shielding the de current flow . Such an embodiment will be exempli fied with reference to Fig . 2B .

Within the vapori zation volume 5 , electric energy may be trans ferred directly to the liquid 8 . The de current flow may flow from one electrode 4a/b through the liquid 8 in the vapori zation volume 5 to the other electrode 4b/a, wherein the liquid 8 may be treated as a resistor . Heat may be generated rapidly and uni formly in the liquid 8 vapori zation volume 5 without any intermediate steps . The larger the amount of de current flow between the pair of electrodes 4a, 4b is , the larger the heating rate is . The amount of de current flow between the pair of electrodes 4a, 4b through the liquid 8 in the vapori zation volume 5 depends on the conductivity of the liquid 8 . The conductivity may depend on various factors such as the temperature of the liquid 8 and its composition, speci fically concentrations of ions and the type of ions .

When the liquid 8 in the vapori zation volume 5 is heated to its boiling temperature , aerosol 2 may be generated . The aerosol 2 may flow out of the vapori zation chamber 3 towards the vapor conduit 9 . The air flow 10 inside the vapor conduit 9 may transport the aerosol 2 out of the vapori zation arrangement 1 such that it may be inhaled by the user . The air flow 10 may be generated by a vacuum generated by the user through sucking, by natural convection, with a fan or similar means of generating a pressure di f ference . The vapor conduit 9 may be provided with a valve which can be opened or closed to allow or prevent the air flow 10 through the vapor conduit 9 . The vapor conduit 9 may be provided with one or more filters to prevent pollutants such as dust or soot particles from entering and/or exiting the vapor conduit 9 .

The de power source 11 applies the electric de potential to the pair of electrodes 4a, 4b . The de power source 11 may be provided by a recti fied ac power source or, preferably, by a battery . The battery may, for example , be a single-use battery such as an alkaline battery or the like , or a rechargeable battery such as a lithium ion accumulator or the like . The vapori zation arrangement 1 may be provided with an interface , comprising, for example , an actuation element such as a button, a slider and/or a rotary knob, in order to allow the user to control an output power of the de power source 11 . The interface may further be used to control one or more valves , to display a current level of the electric or liquid capacity or to ej ect the liquid store 7 or any capsule or pod used to store the liquid 8 . The interface may further comprise a display, such as one or more indicator LEDs for indicating an operation of the vapori zation arrangement 1 , an electric and/or liquid capacity or the like .

Figs . 2A and 2B illustrate a more compact design of the vapori zation arrangement 1 according to other embodiments , wherein the pair of electrodes 4a, 4b is provided perpendicular to the flow direction of the liquid 8 . Figs . 2A and 2B show a cross-sectional view of the vapori zation arrangement 1 which may have a cylindrical shape , wherein the arrow indicating the air flow 10 may coincide with the axis of symmetry . Hence , each electrode 4a/b may have the shape of a disc which is provided with a plurality of holes or as a grating in order to allow the liquid 8 to enter, and the aerosol 2 to exit the vapori zation volume 5 .

The liquid store 7 may be arranged to surround the vapor conduit 9 and the vapori zation chamber 3 . The liquid store 7 may be connected to a secondary reservoir, not shown in Figs . 2A and 2B, such as an exchangeable capsule or pod .

The vapori zation arrangement 1 shown in Fig . 2B is provided with a sediment trap 12 that can hold a residue after heating . The sediment trap 12 may be provided such that it can be easily accesses from the outside in order to remove the residue . The sediment trap 12 may be provided may be provided in the vapori zation chamber 3 in the direction of the liquid conduit 6 . In other words , the sediment trap 12 may be provided below the vapori zation volume 5 to collect the residue after heating .

As shown in Fig . 3 , in addition to a gauze 16 above the pair of electrodes 4a, 4b, leakage of the liquid 8 toward the vapor conduit 9 may further be prevented by providing a recess structure inside the vapori zation chamber 3 and/or the vapor conduit 9 . The recess structure may be arranged to channel the air flow 10 such that intake air flows over the pair of electrodes 4a, 4b above which the recess structure is arranged to capture any unvapori zed liquid and guide it back toward the vapori zation volume 5 . The channeled air flow 10 may ef ficiently skim the aerosol 2 generated in the vapori zation volume 5 . This way, the vapor saturation of the air flow 10 may be increased . The air flow 10 may then be channeled such as to discharge only the generated aerosol 2 toward the vapor conduit 9 .

Figs . 1 , 2A and 2B illustrate embodiments in which the vapori zation chamber 3 is arranged below the fill level of the liquid 8 in the liquid store 7 so that the liquid 8 flows from the liquid store 7 into the vapori zation volume 3 . In other words , as long as the vapori zation volume 5 is located below a current fill level of the liquid 8 within the liquid store 7 , liquid 8 can flow from the liquid store 7 through the liquid conduit 6 into the vapori zation volume 5 via gravity .

Fig . 4 shows the vapori zation arrangement 1 in another embodiment in a cross-sectional view . Here , the liquid store 7 is , for the most part , located below the vapori zation volume 5 . The current fill level of the liquid 8 within the liquid store 7 may lie below the vapori zation volume 5 . However, the liquid conduit 6 and/or the vapori zation chamber 3 may be arranged as part of a capillary arranged to draw liquid 8 from the liquid store 7 into the vapori zation volume 5 . This way, the liquid 8 can flow from the liquid store 7 through the liquid conduit 6 into the vapori zation volume 5 via capillary action : I f a diameter of the capillary is suf ficiently small , then the combination of surface tension and adhesive forces between the liquid 8 and the wall of the capillary act to propel the liquid 8 . The capillary action can occur without the assistance of , or even in opposition to , external forces like gravity . Therefore , the vapori zation arrangement according to this embodiment may operate more reliably in di f ferent orientations .

The vapori zation arrangement 1 of Fig . 4 may further comprise an expansion chamber 15 . The expansion chamber 15 may be arranged to temporarily accommodate the aerosol 2 before trans fer to the vapor conduit 9 . The expansion chamber 15 may be connected to the vapor conduit to allow mixture of the aerosol 2 and air in vapor conduit 9 . In the expansion chamber 15 the aerosol 2 may cool down before it is inhaled by the user . The expansion chamber 15 may be provided with a transparent enclosure such that the user may observe the mixture of the aerosol 2 and air .

Figs . 5A and 5B illustrate the pair of electrodes 4a, 4b according to the embodiment described with reference to Figs . 2A and 2B, wherein the pair of electrodes 4a, 4b are connected to the de power source 11 and have the shape of a disc which is provided with a plurality of holes . Fig . 5A shows the pair of electrodes 4a, 4b from an angled point o f view . The central hole may serve as a duct for the vapor conduit 9 . The smaller holes in electrode 4b may allow liquid 8 to enter the vapori zation volume 5 . The smaller holes in electrode 4a may allow the aerosol 2 , generated via ohmic heating, to exit the vapori zation volume 5 in the direction of the vapor conduit 9 . A gauze 16 may be provided above the electrode 4a to prevent leakage of the liquid 8 into the vapor conduit 9 . Fig . 5B shows the pair of electrodes 4a, 4b from a side view . An insulating spacer 13 may be provided between the pair of electrodes 4 , 4b in order to set a distance between the pair of electrodes 4a, 4b to a certain value . The insulating spacer 13 does not conduct the de current flow . In order to maximi ze the heating ef ficiency, the distance may preferably be 1 mm or less , and more preferably be 0 . 5mm or less .

The vapori zation arrangement 1 may be provided with a current regulator 14 , as shown schematically in the circuit diagram of Fig . 6 . The de power source 11 is connected via the current regulator 14 to the pair of electrodes 4 , 4b, not shown in Fig . 6 . The de current flow may flow through the liquid 8 in the vapori zation volume 5 and said liquid 8 may be treated as a resistor .

The current regulator 14 may control the de current flow between the two electrodes 4a, 4b and the liquid 8 in the vapori zation volume 5 on the basis of a target vapori zation power . The target vapori zation power may be based on the conductivity or resistance of the liquid 8 , an output voltage of the de power supply 11 , the distance between the pair o f electrodes 4a, 4b and a desired amount of generated aerosol 2 .

Fig . 7 shows a plot of the conductivity of the liquid 8 with respect to the temperature of the liquid 8 . The curve corresponds to a polynomial fit of second order to data points taken from the literature . The solid part of the curve represents the range described by the literature and the dotted part of the curve represent the extrapolation of the former . The conductivity is normali zed to the value o f conductivity of the liquid 8 at a temperature of 20 ° C of the liquid 8 . As can be seen from Fig . 7 , below around 25 ° C, the liquid 8 has a low conductivity which corresponds to a high resistance of the liquid 8 .

In the following, several exemplary values of the resistance and conductivity of typical formulations of the liquid 8 for the use in electronic cigarettes are given, wherein it i s assumed that the liquid 8 has a temperature of or below 25 ° C . One formulation comprising 12 mg/ml nicotine may have a conductivity of 5 pS/cm resulting in a resistance of 20 kQ or 10 kQ for electrodes having a distance of 1 mm or 0 . 5 mm, respectively . Another formulation comprising 18 mg/ml nicotine and mixed with benzoic acid may have a conductivity of 18 pS/cm resulting in a resistance of 5555 Q or 2778 Q for electrodes having a distance of 1 mm or 0 . 5 mm, respectively . When diluted with 10 ( 20 ) volume percent of ultrapure water , said formulation comprising 18 mg/ml nicotine and mixed with benzoic acid may have a conductivity of 68 ( 124 ) pS/cm resulting in a resistance of 1471 Q ( 806 Q) or 735 Q ( 403 Q) for electrodes having a distance of 1 mm or 0 . 5 mm, respectively .

The vapori zation arrangement 1 further comprises an electric circuitry that is arranged to measure a current associated with the de current flow between the pair of electrodes 4a, 4b . The electric circuit is further arranged to determine a liquid resistance based on the electric de potential and the measured current . The de power source 11 may apply a constant electric de potential to the pair of electrodes 4a, 4b during the measurement of the current . The electric circuitry may further be arranged to measure a voltage associated with the electric de potential . The electric circuitry may be implemented using a processing unit and a memory . Furthermore, the electric circuitry is arranged to control an operation of the vaporization arrangement based on the liquid resistance. The operation may, for example, control an amount of electric power delivered to the pair of electrodes 4a, 4b. The operation may, for example, store values of the current measurement and the electric de potential in a memory or retrieve said values therefrom. The operation may, for example, transmit a notification to the user. For example, the notification may be transmitted via a status LED or by generating a haptic feedback.

Figs. 8A shows a plot of the resistance of different formulations of the liquid with respect to time. From top to bottom, the curves correspond to 5.675 mg of liquid 8 with 0%, 10%, 20% and 30% water content, respectively, which is heated with 7 W of power. The liquid resistance may be associated with an amount of water and/or an amount of benzoic acid in the liquid.

Fig. 8B shows a plot of the temperature of different formulations of the liquid with respect to time. From top to bottom, the curves correspond to 5.675 mg of liquid 8 with 30, 20, 10 and 0 volume percent of water content, respectively, which is heated with 7 W of power. Water hay have a much higher specific heat parameter than the other main ingredients of the liquid. It is expected that the higher the water content of the liquid is, the slower the heat-up process is.

For example, in a time interval between 0.1 s and 0.2 s of heating, the liquid resistance decreases by 198 Q, 212 Q, 225 Q and 238 Q for a liquid 8 with 0, 10, 20 and 30 volume percent of water content, respectively. The time interval between 0.1 s and 0.2 s of heating may be a first puffing period in which aerosol 2 is generated in inhaled by the user .

The electric circuitry may further be arranged to measure a voltage associated with the electric de potential , measure a change in voltage associated with electric de potential and a change in current associated with the de current flow in a puf fing period, and determine a change rate of the liquid resistance in the puf fing period based on the change in voltage and the change in current in the puf fing period . The change in voltage/current may be measured by measuring a voltage/current and the start and end of the puf fing period .

The electric circuitry may further be arranged to disable generating the aerosol 2 i f the determined change rate of the liquid resistance is higher than a change rate threshold . In other words , it may be determined that the measured change rate is not compatible with the expectation for a liquid 8 with acceptable water content , as exempli fied in Fig . 8A, and, as a result , the generation of aerosol 2 may be disabled . An acceptable water content may, for example , be 10 volume percent or less . This method of quality control avoids the inhalation, by the user, of aerosol 2 generated from liquid 8 with high water content .

Fig . 9 shows a plot of the conductivity of the liquid 8 with respect to the concentration of NaCl in the liquid 8 . Here , the formulation of the liquid 8 comprises 18 mg/ml nicotine diluted with 10 volume percent of ultrapure water and mixed with acid . In order to improve the conductivity of the liquid and to enable anti-counterfeit functionality, an agent such as sodium chloride (NaCl ) may be added to the liquid 8 which may increase the electrical conductivity of the liquid 8 as shown in the plot . Hence , the liquid resistance decreases as the concentration of NaCl in the liquid 8 increases . Thi s way, the liquid 8 may be identified to be genuine i f the measured liquid resistance is compatible with the expectation for a formulation containing at least a speci fied concentration of NaCl .

The electric circuitry may be arranged to control the de power source 11 to apply the electric de potential to the pair of electrodes 4a, 4b at a first voltage level for a first period, to determine the liquid resistance based on the first voltage level and the measured current , and to compare the liquid resistance with a safety threshold . A liquid resistance smaller than the safety threshold may be indicative of a short circuit between the pair of electrodes 4a, 4b and thus present a potential safety hazard . Thus , the electric circuitry may further be arranged to control the vapori zation arrangement to noti fy the user about a technical error i f the liquid resistance is smaller than the safety threshold . The electric circuitry may further be arranged to control the de power source 11 to apply the electric de potential to the pair of electrodes 4a, 4b at a second voltage level for a second period, wherein the second voltage level is higher than the first voltage level , and to determine the liquid resistance based on the second voltage level and the measured current . The electric circuitry may further be arranged to obtain a mean value of liquid resistance in the second period based on a plurality of current measurements associated with the de current flow and compare the mean value with a working threshold, wherein the working threshold is higher than the safety threshold . The electric circuitry may then prohibit aerosol generation, i f the mean value of liquid resistance is higher than the working threshold, and enable aerosol generation i f the mean value of l iquid resistance is smaller or equal to the working threshold . This way, the liquid 8 may be identi fied to be genuine and an anti-counterfeiting functionally is provided .

The vapori zation arrangement may further comprise an indication means to indicate the operation according to the liquid resistance . The indication means may be provided by a status LED or a display .

Fig . 10 shows a flowchart representing the control logic of a vapori zation arrangement 1 with quality control and anticounterfeit means .

In step S 10 , the insertion of liquid 8 is detected . The vapori zation arrangement 1 may further comprise a capsule comprising the liquid 8 to be vapori zed . The capsule may be provided in a detachable manner and the vapori zation arrangement 1 may be arranged to detect insertion of the capsule .

In step S20 , electric circuitry controls the de power source 11 to apply the electric de potential to the pair of electrodes 4a, 4b at a first voltage level for a first period . Furthermore , a counter N is set to zero (N = 0 ) . The first voltage level may, for example , be 4 V . The first period may, for example , be 10 ms .

In step S30 , the electric circuitry determines the liquid resistance based on the first voltage level and the measured current . Furthermore , the counter N is incremented by one (N + 1 ) . A vapori zation arrangement 1 comprising a capsule that holds the liquid 8 and that is arranged to detect insertion of the capsule and initiate determining the liquid resistance for the inserted capsule . In step S40, the electric circuitry compares the liquid resistance with a safety threshold and determine whether or not the current resistance is larger than the safety threshold. The safety threshold may, for example, be a value in the range between 10 and 100 Q.

If the current resistance is not larger than the safety threshold (NO in step S40) , it is determined, in step S50, whether or not the counter N is larger than three (N > 3) .

If the counter N is not larger than three (N > 3) (NO in step S50) , the control logic continues with step S30. This way, the measurement of the liquid resistance is repeated up to two times.

If the counter N is larger than three (N > 3) (YES in step S50) , the electric circuitry notifies user about a technical error. The technical error may, for example, be a short circuit between the pair of electrodes 4a, 4b. This way, the user may desist from operating the vaporization arrangement 1 and/or be advised to change the liquid 8.

If the current resistance is larger than the safety threshold (YES in step S40) , the electric circuitry controls, in step S70, the de power source 11 to apply the electric de potential to the pair of electrodes 4a, 4b at a second voltage level for a second period, wherein the second voltage level is higher than the first voltage level. The second voltage level may, for example, be 60 V.

In step S80, the electric circuitry obtains a mean value of liquid resistance in the second period based on a plurality of current measurements associated with the de current flow. For example, the electric circuitry may determine a plurality of five values for the liquid resistance based on the second voltage level and a plurality of five current measurements every 10 ms. The electric circuitry may obtain the mean value of liquid resistance by throwing away the minimum and maximum values and calculate an arithmetic mean from the remaining three values of the liquid resistance.

In step S90, the electric circuitry determines whether or not the mean value of liquid resistance is larger than a working threshold. The working threshold may, for example, be 514 Q. Alternatively, the working threshold may be slightly higher, for example 600 Q, that will still allow vaporization of the liquid 8 just with higher delay between activation and vapor delivery .

If the mean value of liquid resistance is larger than the working threshold (YES in step S90) , the electric circuitry detects, in step S100, that there is no liquid or that the liquid is not genuine. As a consequence, the electric circuitry may then prohibit aerosol generation.

If the mean value of liquid resistance is larger than the working threshold (No in step S90) , the electric circuitry enables, in step S110, aerosol generation, thereby allowing inhalation of the generated aerosol 2 by the user.

[Reference Signs]

1 vaporization arrangement

2 aerosol

3 vaporization chamber

4a, 4b pair of electrodes

5 vaporization volume

6 liquid conduit

7 liquid store 8 liquid

9 vapor conduit

10 air flow

11 de power source 12 sediment trap

13 insulating spacer

14 current regulator

15 expansion chamber

16 gauze