MEASUREMENT DEVICE AND PROCESS FOR AN AEROSOL GENERATING DEVICE LIFECYCLE TESTING ARRANGEMENT

Abstract

There is provided a testing apparatus for analysing an aerosol generated by an aerosol-generating system comprising an aerosol-forming substrate and a mouthpiece. The testing apparatus comprises an airflow channel that extends from a first channel opening that is configured to receive a mouthpiece of an aerosol-generating system. The testing apparatus further comprises a sensing assembly comprising an emitter configured to emit electromagnetic radiation into the airflow channel and a receiver configured to receive at least some of the electromagnetic radiation from the airflow channel. The testing apparatus further comprises a pump assembly that, in a first configuration of the testing apparatus, is configured to draw air through the airflow channel in a first direction such that an aerosol generated by the aerosol-generating system in use is drawn from the mouthpiece received in the first channel opening and through the airflow channel; and a controller configured to determine at least one characteristic of the aerosol drawn through the airflow channel based on signals received from the sensing assembly. There is also provided a method of analysing an aerosol using the testing apparatus and a method detecting a defect in an aerosol-generating system.

Claims

1-15. (canceled)

16. A testing apparatus for analysing an aerosol generated by an aerosol-generating system comprising an aerosol-forming substrate and a mouthpiece, the testing apparatus comprising: an airflow channel that extends from a first channel opening that is configured to receive a mouthpiece of an aerosol-generating system; a sensing assembly comprising an emitter configured to emit electromagnetic radiation into the airflow channel and a receiver configured to receive at least some of the electromagnetic radiation from the airflow channel; a pump assembly that, in a first configuration of the testing apparatus, is configured to draw air through the airflow channel in a first direction such that an aerosol generated by the aerosol-generating system in use is drawn from the mouthpiece received in the first channel opening and through the airflow channel; and a controller configured to determine at least one characteristic of the aerosol drawn through the airflow channel based on signals received from the sensing assembly; the airflow channel further comprising a second channel opening and the testing apparatus further comprising a valve assembly; wherein the pump assembly, in a second configuration of the testing apparatus, is configured to draw purge air through the airflow channel in a second direction that is opposite to the first direction; and wherein the pump assembly, in a third configuration of the testing apparatus, is configured to draw purge air through the airflow channel in the first direction; wherein the valve assembly is configured such that when the testing apparatus is in the first configuration, the first channel opening is open and the second channel opening is closed; wherein the valve assembly is further configured such that when the testing apparatus is in the second and third configurations, the first channel opening is closed and the second channel opening is open.

17. A testing apparatus according to claim 16, wherein the controller is configured to compare the at least one determined characteristic to one or more predetermined values for the or each characteristic or one or more predetermined range of values for the or each characteristic.

18. A testing apparatus according to claim 17, wherein the controller is configured to determine that the aerosol-generating system is defective if at least one of the determined characteristics is not equal to one of the predetermined values for that characteristic or does not fall within one of the predetermined ranges of values for that characteristic.

19. A testing apparatus according to claim 16, wherein a first characteristic of the aerosol determined by the controller is related to the transmittance of the aerosol.

20. A testing apparatus according to claim 16, wherein the sensing assembly further comprises a temperature sensor configured to measure a temperature of a portion of the airflow channel.

21. A testing apparatus according to claim 20, wherein a second characteristic of the aerosol determined by the controller is temperature.

22. A testing apparatus according to claim 16, wherein the sensing assembly further comprises a pressure sensor configured to measure a pressure in a portion of the airflow channel.

23. A testing apparatus according to claim 22, wherein a third characteristic determined by the controller is a pressure drop.

24. A testing apparatus according to claim 16, wherein the emitter comprises one or more LEDs.

25. A method of analysing an aerosol generated by an aerosol-generating system comprising an aerosol-forming substrate and a mouthpiece using the testing apparatus of claim 16, the method comprising: positioning the mouthpiece of the aerosol-generating system such that the mouthpiece is received in the first channel opening; when the testing apparatus is in the first configuration, using the pump assembly to draw air through the airflow channel in a first direction such that an aerosol generated by the aerosol-generating system is drawn from the mouthpiece received in the first channel opening and through the airflow channel; determining at least one characteristic of the aerosol drawn through the airflow channel based on signals received from the sensing assembly; using the pump assembly, in a second configuration of the testing apparatus, to draw purge air through the airflow channel in a second direction that is opposite to the first direction; and using the pump assembly, in a third configuration of the testing apparatus, to draw purge air through the airflow channel in the first direction; wherein when the testing apparatus is in the first configuration, the first channel opening is open and the second channel opening is closed; wherein when the testing apparatus is in the second and third configurations, the first channel opening is closed and the second channel opening is open.

26. A method according to claim 25, further comprising comparing the at least one determined characteristic to one or more predetermined values for the at least one characteristic or one or more predetermined range of values for the at least one characteristic.

27. A method according to claim 26, further comprising determining that the aerosol-generating system or the aerosol-forming substrate is defective if at least one of the determined characteristics is not equal to one of the predetermined values for that characteristic or does not fall within one of the predetermined ranges of values for that characteristic.

28. A method of detecting a defect in an aerosol-generating system comprising an aerosol-forming substrate and a mouthpiece, the method comprising: positioning the mouthpiece of the aerosol-generating device such that the mouthpiece is received in a first channel opening of an airflow channel of a testing apparatus according to claim 16; using the pump assembly of the testing apparatus, in a first configuration of the testing apparatus, to draw air through the airflow channel in a first direction such that an aerosol generated by the aerosol-generating system is drawn from the mouthpiece received in the first channel opening and through the airflow channel; determining at least one characteristic of the aerosol drawn through the airflow channel using the sensing assembly; comparing the at least one determined characteristic to one or more predetermined values for the or each characteristic or one or more predetermined range of values for the or each characteristic; and determining that the aerosol-generating system is defective if at least one of the determined characteristics is not equal to one of the predetermined values for that characteristic or does not fall within one of the predetermined ranges of values for that characteristic; using the pump assembly, in a second configuration of the testing apparatus, to draw purge air through the airflow channel in a second direction that is opposite to the first direction; and using the pump assembly, in a third configuration of the testing apparatus, to draw purge air through the airflow channel in the first direction; wherein when the testing apparatus is in the first configuration, the first channel opening is open and the second channel opening is closed; wherein when the testing apparatus is in the second and third configurations, the first channel opening is closed and the second channel opening is open.

29. A method according to claim 28, wherein the at least one characteristic comprises a first characteristic that is the transmittance of electromagnetic radiation through the aerosol.

30. A method according to claim 28, wherein the at least one characteristic comprises a second characteristic that is the temperature of the aerosol.

31. A method according to claim 29, wherein the at least one characteristic comprises a second characteristic that is the temperature of the aerosol.

Description

[0233] Examples will now be further described with reference to the figures in which:

[0234] FIG. 1 is a schematic of a testing apparatus according to a first embodiment in combination with a first aerosol-generating system;

[0235] FIG. 2 is a schematic cross-section of the first aerosol-generating system of FIG. 1;

[0236] FIG. 3 is a flow diagram of a method of analysing an aerosol generated by the first aerosol-generating system of FIG. 2 using the testing apparatus of FIG. 1;

[0237] FIG. 4 is a schematic of the testing apparatus of FIG. 1 in a first configuration;

[0238] FIG. 5 is a graph representing the transmittance of aerosol generated in use of the first aerosol-generating system of FIG. 1 for successive puffs;

[0239] FIG. 6 is a graph representing the temperature of aerosol generated in use of the aerosol-generating system of FIG. 1 for successive puffs;

[0240] FIG. 7 is a schematic of the testing apparatus of FIG. 1 in a second configuration;

[0241] FIG. 8 is a schematic of the testing apparatus of FIG. 1 in a third configuration;

[0242] FIG. 9 is a schematic of a second embodiment of a testing apparatus that is suitable for analysing the aerosol generated by two aerosol-generating systems;

[0243] FIG. 10 is a schematic of third embodiment of a testing apparatus that is suitable for analysing the aerosol generated by two aerosol-generating systems, the testing apparatus being in a first position; and

[0244] FIG. 11 is schematic of the third embodiment of the testing apparatus, the testing apparatus in a second position.

[0245] FIG. 1 is a schematic of a testing apparatus 100 in which a first aerosol-generating system 200 is received. The aerosol-generating system 200 is shown in more detail, separately from the testing apparatus 100, as a cross-sectional schematic view in FIG. 2.

[0246] The testing apparatus 100 comprises an airflow channel 102.

[0247] A first branch 104 of the airflow channel extends from a first channel opening 105 that is configured to receive a mouthpiece of the aerosol-generating system 200. The first channel opening 105 comprises a machined mouthpiece receiving portion (not shown in the figures) which is shaped to receive the mouthpiece of the aerosol-generating system 200 in an opening of the mouthpiece receiving portion and to provide a seal between the testing apparatus and the mouthpiece of the aerosol-generating system 200. The mouthpiece of the aerosol-generating system 200 is not shown in FIG. 1 because it is received in the first channel opening 105 but is shown in FIG. 2 as feature 204.

[0248] A second branch 106 of the airflow channel extends from a second channel opening 107 that is open to the atmosphere. The first branch 104 and second branch 106 merge at a first junction 108.

[0249] Between the first channel opening 105 and the first junction 108 is a first valve 112. The first valve 112 is a pinch valve and is controllable to open or close. When the first valve 112 is open, air is able to flow from the first channel opening 105, through the first branch 104 and on through the airflow channel 102 (or vice versa). When the first valve 112 is closed, air is prevented from being able to flow from the first channel opening 105 and through the first branch 104 (or vice versa). When the first valve 112 is closed, the first channel opening 105 may be referred to as being closed.

[0250] Between the second channel opening 107 and the first junction 108 is a second valve 116. The second valve 116 is an electromechanically operated valve and is controllable to open or close. When the second valve 116 is open, air is able to flow from the second channel opening 107, through the second branch 106 and on through the airflow channel 102 (or vice versa). When the second valve 116 is closed, air is prevented from being able to flow from the second channel opening 107 and through the second branch 106 (or vice versa). When the second valve 116 is closed, the second channel opening 107 may be referred to as being closed.

[0251] Downstream of the first junction 108, the airflow channel 108 passes through a sensing assembly 118 and continues to a second junction 113. Between the second junction 113 and the second valve 116 is positioned a filter element 121.

[0252] The sensing assembly 118 comprises an emitter 140 comprising a plurality of LEDs configured to emit electromagnetic radiation into the airflow channel. The electromagnetic radiation has a wavelength in the visible range of the electromagnetic spectrum. In particular, the LEDs are configured to emit electromagnetic radiation at a single wavelength of 625 nanometres.

[0253] The sensing assembly 118 further comprises a receiver 142 in the form of a fibre sensor. The receiver 142 is configured to receive at least some of the electromagnetic radiation emitted into the airflow channel by the emitter 140. The emitter 140 and receiver 142 are positioned on opposite sides of the airflow channel 102. In this way, electromagnetic radiation received by the receiver 142 from the emitter 140 must have passed through the airflow channel 102. Thus, the electromagnetic radiation must have interacted with the air in the airflow channel.

[0254] The sensing assembly 118 further comprises a temperature sensor 144. The temperature sensor 144 is a thermocouple. The temperature sensor is suitable for measuring temperatures of between about minus 50 degrees Celsius and 350 degrees Celsius. The temperature sensor 144 is configured to measure a temperature of a portion of the airflow channel 102. In this way, it is possible to determine the temperature of air flowing through the airflow channel 102.

[0255] The sensing assembly 118 further comprises a pressure sensor 146. The pressure sensor 146 is configured to measure a pressure drop of a portion of the airflow channel 102.

[0256] A third branch 122 of the airflow channel 102 extends from the second junction 113 to a third channel opening 124. The third channel opening 124 is open to the atmosphere.

[0257] A fourth branch 126 of the airflow channel 102 extends from the second junction 113 to a fourth channel opening 128. Again, the fourth channel opening 128 is open to the atmosphere.

[0258] Between the second junction 113 and the third channel opening 124 is positioned a third valve 130 and a first pump 132. The third valve 130 is an electromechanical valve and is controllable to open or close. When the third valve 130 is open, air is able to flow from the second junction 113, through the third branch 122 and on to the third channel opening 124 (or vice versa). When the third valve 130 is closed, air is prevented from being able to flow from the second junction 113, through the third branch 122 and on to the third channel opening 124 (or vice versa). When the third valve 130 is closed, the third channel opening 124 may be referred to as being closed.

[0259] The first pump 132 is a suction pump. The first pump 132 is controllable to be either on or off. When the first pump 132 is controlled to be switched on, the first pump 132 is configured to draw air through the airflow channel 102 in a first direction such that air is drawn through the airflow channel so as to flow from the first junction 108 towards the second junction 113.

[0260] Between the second junction 113 and the fourth channel opening 128 is positioned a fourth valve 134 and a second pump 136. The fourth valve 134 is an electromechanical valve and is controllable to open or close. When the fourth valve 134 is open, air is able to flow from the second junction 113, through the fourth branch 126 and on to the fourth channel opening 128 (or vice versa). When the fourth valve 134 is closed, air is prevented from being able to flow from the second junction 113, through the fourth branch 126 and on to the fourth channel opening 128 (or vice versa). When the fourth valve 134 is closed, the fourth channel opening 128 may be referred to as being closed.

[0261] The second pump 136 may be referred to as an exhaust pump. The second pump 136 is controllable to be off, on in a suction mode or on in a blowing mode. When the second pump 136 is controlled to be switched on in the suction mode, the second pump 136 is configured to draw air through the airflow channel 102 in the first direction such that air is drawn through the airflow channel so as to flow from the first junction 108 towards the second junction 113. When the second pump 136 is controlled to be switched on in the blowing mode, the second pump 136 is configured to draw air through the airflow channel 102 in a second direction such that air is drawn through the airflow channel so as to flow from the second junction 113 towards the first junction 108.

[0262] The first and second pumps 132, 136 together may together be referred to as a pump assembly 138. The pump assembly 138 and the first, second, third and fourth valves 112, 116, 130 and 134 are controlled by a controller of the testing assembly, not shown in the figures. The controller is configured to control the first and second pumps to be switched on or off, and in the case of the second pump, to be in the suction or blowing modes when switched on. The controller is also configured to open or close the first, second, third and fourth valves, as required. In particular, the controller controls the pumping assembly and valves according to different configurations of the testing apparatus. This is described in more detail below.

[0263] Although the second, third and fourth channel openings have all been described as being open to the atmosphere, it is also possible for any or all of these openings to be connected to a ventilation system or a waste container that is separate to the testing apparatus. This would ensure that any exhausted air from the testing apparatus is contained. In such embodiments, it may not be necessary to include the filter elements 121 in the testing apparatus 100. However, the presence of the filter elements 121 would still provide the benefit of protecting the pump from the generated aerosol.

[0264] FIG. 2 is a cross-sectional schematic view of the first aerosol-generating system 200 that is shown in combination with the testing apparatus 100 in FIG. 1. The aerosol-generating system 200 comprises an aerosol-generating device 202 comprising a chamber 210 defined by a device housing. The chamber 210 is tubular, made of a stainless steel and has at an upstream end a base. The chamber 210 is configured for receiving an aerosol-generating article 300.

[0265] The aerosol-generating article 300 received in the chamber 210 contains an aerosol-forming substrate 306. The aerosol-forming substrate is a solid tobacco-containing substrate. In particular, the aerosol-forming substrate is a gathered sheet of homogenised tobacco. As shown in FIG. 2, the aerosol-generating article and chamber are configured such that a mouth end of the aerosol-generating article 300 protrudes out of the chamber 10 and out of the aerosol-generating device when the aerosol-generating article is received in the chamber. This mouth end forms a mouthpiece 304. In normal use of the aerosol-generating system 200, a user of the system may puff on the mouthpiece 304 in use. However, when the aerosol-generating system 200 is used with the testing apparatus 100 of FIG. 1, the mouthpiece 304 is instead received in the first channel opening 105 of the testing apparatus 100.

[0266] The aerosol-generating device 202 comprises a heater assembly comprising a heating element 211. The heating element 211 surrounds the chamber 10 along a portion of the chamber in which the aerosol-forming substrate 306 of the aerosol-generating article 202 is received. The heating element 211 is a resistive heating element.

[0267] An airflow channel 220 extends from an air inlet 222 of the aerosol-generating device 100. Upstream of the chamber, the airflow channel 220 is primarily defined by an airflow channel wall 224. Downstream of the airflow channel wall 224, the airflow channel 220 passes through an air inlet defined in the base of the chamber. The airflow channel 220 then extends through the chamber 210. In particular, air flowing through the airflow channel 220 passes into the aerosol-generating article 300 at its distal end.

[0268] The aerosol-generating device 202 further comprises a power supply 242 in the form of a rechargeable battery for powering the heating element 211 controllable by a controller of the device (not shown). The power supply is connected to the controller and the heating element 211 via electrical wires and connections that are not shown in the Figures. The aerosol-generating device may comprise further elements, not shown in the Figures, such as a button for activating the aerosol-generating device.

[0269] In use of the aerosol-generating system 100, air is drawn through the mouthpiece 304 of the received aerosol-generating article 300 resulting in air being drawn through the airflow channel 220 towards the mouthpiece 304. Air will be drawn from outside of the aerosol-generating device into the airflow channel 220 through air inlet 222. Because the aerosol-generating article 300 is received in the chamber, the air drawn into the chamber will enter the aerosol-generating article 300 at its distal end. Thus, the air passes through the aerosol-forming substrate 306. In doing so, volatile compounds generated by the heating of the substrate 306 will become entrained in the air. As the air continues towards the mouthpiece 304 of the aerosol-generating article 300, the volatile compounds cool to form an aerosol. The air and entrained aerosol then exits the aerosol-generating article 300 through the mouthpiece 304

[0270] In normal use of the aerosol-generating system 200, it is a user puffing on the mouthpiece 304 that results in air being drawn through the airflow channel 220, as described above. During a puff, a user inhales through the aerosol-generating system 100 and so draws air through the aerosol-generating system 200.

[0271] However, when the aerosol-generating system 200 is used with the testing apparatus 100, as shown in FIG. 1, it is the testing apparatus 100, and specifically the pump assembly 138 of the testing apparatus 100, that imitates a user puffing and draws air through the aerosol-generating system 200. The purpose of this is so that the generated aerosol enters the airflow channel 102 and past the sensing assembly 118 of the testing apparatus 100 to be analysed. Analysis of the generated aerosol allows defective aerosol-generating systems 200 to be detected and is particularly important in the context of quality assurance testing in relation to the production of the aerosol-generating system 200 or components of that system (particularly consumable components of that system).

[0272] FIG. 3 shows a flow diagram showing the steps analysing an aerosol generated by the aerosol-generating system of FIG. 2 using the testing apparatus shown in FIG. 1.

[0273] Step 402 of the method is to position the aerosol-generating system 200 in the testing apparatus 100. In particular, the mouthpiece 304 of the aerosol-generating system is inserted into the mouthpiece receiving portion of the first channel opening 105 of the testing apparatus 100.

[0274] Step 404 of the method is to draw generated aerosol into the testing apparatus 100 using the pump assembly 138. Step 404 first comprises configuring the testing apparatus 100 of FIG. 1 to be in a first configuration, as shown in FIG. 4. The controller of the testing apparatus is configured to open the first valve 112 and the third valve 130 and to close the second valve 116 and the fourth valve 134. If the valves are already in their respective open or closed state for the first configuration, the controller is configured to maintain the valves in that state. For example, if the first valve 112 is already open, the controller is maintains the first valve in that open position.

[0275] The controller is also configured to turn on the first pump 132 to draw air through the airflow channel in the first direction. Air is not able to enter the airflow channel 102 through the second or fourth channel openings 107, 128 because the second and fourth valves 116, 134 are closed. Thus, when the first pump 132 draws air through the airflow channel 102 in the first direction, that air must be drawn into the airflow channel 102 through the first channel opening 105 and so also through the aerosol-generating system 200 whose mouthpiece 204 is received in the first channel opening 105. The pump assembly 138 mimics a user puffing on the aerosol-generating system 200. The air flow through the testing apparatus 100 in the first configuration is represented by the dotted arrows in FIG. 4.

[0276] The aerosol-generating system 200 is an electrically heated aerosol-generating system and so, for aerosol to be generated, the aerosol-generating device 202 should be activated to heat the aerosol. In some embodiments, the aerosol-generating device 202 comprises a button for activating the device which should be pressed by the user to activate the device. This may be before or during the step of the pump assembly drawing air through the airflow channel. Alternatively or additionally, in other embodiments, the aerosol-generating device 200 comprises a puff detector system that is configured to activate the device upon detecting a puff. In such embodiments, the aerosol-generating device 200 is activated automatically upon detection of a puff and so is activated by the pump assembly 138 drawing air through the airflow channel 102.

[0277] Once the aerosol-generating device 202 has been activated, the heater element 210 will heat up the aerosol-forming substrate 306 to generate an aerosol, as described above in relation to FIG. 2. This generated aerosol will then be entrained in the air drawn through the airflow channel 102 by the pump assembly 138.

[0278] Step 406 of the method is to determine a characteristic of the generated aerosol. This step is performed by the controller of the testing apparatus based on signals received from the sensing assembly 118.

[0279] Step 406 comprises determining a first characteristic of the generated aerosol which is the transmittance of the aerosol. The transmittance of a material is defined as the ratio of light energy transmitted through a body to the light energy falling on it. In this case, the body is the generated aerosol.

[0280] The light energy transmitted through the generated aerosol is determined by the controller based on signals received from the receiver 142 while generated aerosol is drawn through the airflow channel 102. This is because the generated aerosol will pass through the sensing assembly 118 such that electromagnetic radiation emitted by the emitter 140 will interact with (and be absorbed by) the aerosol. Thus, the intensity of electromagnetic radiation received by the receiver 142 is representative of the amount of energy transmitted through the generated aerosol. This intensity is a first intensity.

[0281] In some embodiments, the light energy falling on the generated aerosol is a predetermined value that is stored in a memory of the controller of the testing apparatus. In some embodiments, the light energy falling on the generated aerosol is alternatively or additionally measured prior to step 404. In particular, the controller of the testing apparatus is configured to measure the intensity of electromagnetic radiation received at the receiver 142 from the emitter 140 when no aerosol has yet been generated. This intensity is a second intensity.

[0282] The controller of the testing apparatus 100 is configured to determine the transmittance of the generated aerosol by calculating the ratio of the first intensity to the second intensity.

[0283] Step 408 of the method comprises comparing the first characteristic (i.e. the determined transmittance) to a predetermined range of values for the transmittance. The predetermined range of values represent values for the transmittance of an aerosol generated by an aerosol-generating system that is operating correctly.

[0284] The predetermined range of values are known values that are determined from prior experimentation. For example, such experimentation may comprise measuring the transmittance of an aerosol generated by a large number of aerosol-generating systems that are known to operate correctly (i.e. without a defect). The predetermined range of values may then be determined based on an average of the transmittance values and the spread or standard deviation of the transmittance values.

[0285] The predetermined range of values used in the comparison are specific to the type of aerosol-generating system being tested. The predetermined range of values are also specific to the type of aerosol-forming substrate of the aerosol-generating system being tested (if the aerosol-generating system is capable of operating with different aerosol-forming substrates).

[0286] The predetermined range of values are stored in a memory of the controller of the testing apparatus. In some embodiments, the method can additionally comprise inputting the predetermined range of values into the memory manually or by uploading the predetermined range of values to the memory from a central database, for example.

[0287] Step 408 comprises step 409 of checking if the characteristic is outside of a predetermined range.

[0288] Step 410 of the method is carried out if the determined characteristic is outside the predetermined range of values for that characteristic. Step 410 of the method is to determine that the aerosol-generating system 200 is defective. If the aerosol-generating system 200 is determined to be defective, the testing device 100 will inform a user. This may be via a user interface of the testing device 100 (not shown in the Figures), for example in the form of an error message on a screen of the user interface, by emitting a sound or by lighting an error LED on the user interface.

[0289] Step 412 of the method is carried out if the determined characteristic is within the predetermined range of values for that characteristic. Step 412 on FIG. 4 is to take no action. In some embodiments, however, the testing device will inform a user that the aerosol-generating system 200 being tested is not defective.

[0290] In some embodiments, step 412 is followed by repeating steps 406 and 408 for further characteristics of the generated aerosol and while generated aerosol is drawn into the testing apparatus 100. In some embodiments, the controller performs steps 406 and 408 for further characteristics at the same time as for the first characteristics.

[0291] In some embodiments, the method may comprise comparing the or each characteristic to a respective single predetermined value rather than a range of predetermined values. The principle is the same. The single predetermined value is known from prior experimentation.

[0292] Steps 406 and 408 are repeated by determining a second and third characteristic of the generated aerosol and comparing the second and third characteristics to respective predetermined ranges of values. The second characteristic is the temperature of generated aerosol. The third characteristic is the pressure drop when aerosol is generated compared to an ambient pressure.

[0293] The second characteristic is determined by the controller of the testing apparatus based on signals received at the controller from the temperature sensor 144.

[0294] The third characteristic is determined by the controller of the testing apparatus based on signals received at the controller from the pressure sensor 146. The pressure sensor 146 is a differential pressure sensor and so the pressure drop in the airflow channel can be determined directly.

[0295] Again, the predetermined range of values for the second and third characteristics are known values derived from prior experimentation in relation to the specific type of aerosol-generating system and aerosol-forming substrate being tested.

[0296] In some embodiments, the controller is configured to determine that the aerosol-generating device is defective if any of one the first to third characteristics is outside of the respective predetermined range. In some embodiments, the controller is configured to determine that the aerosol-generating device is defective only if two or three of the first to third characteristics is outside of the respective predetermined range.

[0297] Steps 406 and 408 are performed (and repeated) simultaneously to step 404. Step 404 continues for a predetermined time that is representative a typical user puff. The predetermined time is 2 seconds. At the end of the predetermined time, step 404 comes to end and the controller of the testing apparatus 100 is configured to switch the first pump 132 off.

[0298] In some embodiments, the method comprises repeating steps 404 onwards of FIG. 3 for a number of subsequent puffs. In one embodiment, steps 404 onwards of FIG. 3 are repeated nine times (i.e. for nine further puffs). Optionally, there is a delay of about 30 seconds between each repetition of steps 404 onwards. This repetition is intended to mimic a real-world usage session of the aerosol-generating system 200.

[0299] The characteristics of an aerosol generated by a normally operating aerosol-generating system (i.e. one that is not defective) will typically vary for subsequent puffs.

[0300] FIG. 5 is a graph representing how the transmittance of an aerosol generated by a particular aerosol-generating system varies for subsequent puffs. y axis 502 represents transmittance, x axis 504 represents puff number. As the number of puffs progresses, the transmittance initially falls and then rises again towards the end of the usage session. The change in transmittance will depend on how the quantity of generated aerosol and chemical composition of that aerosol changes for subsequent puffs. Different aerosol-generating systems and different aerosol-forming substrates will have a different pattern.

[0301] FIG. 6 is a graph representing how the temperature of the aerosol generated by the aerosol-generating system of FIG. 5 varies for subsequent puffs. y axis 602 represents temperature, x axis 604 represent puff number. The general trend of aerosol temperature is to decrease as the number of puffs increases. This may be because of the heating profile employed by the aerosol-generating device of the particular aerosol-generating system. It may also result from a changing chemistry of the aerosol-forming substrate as the substrate is depleted.

[0302] The pressure drop can follow a similar pattern to the temperature wherein the pressure drop decreases for increasing puff number.

[0303] To account for the changing characteristics of an aerosol generated by a normally operating aerosol-generating system for subsequent puffs, the method comprises comparing the determined characteristics to different predetermined ranges of values for subsequent puffs. For example, the predetermined range of values for the transmittance follows a decreasing and then increasing pattern for subsequent puffs, similar to the trend shown in the graph of FIG. 5. The predetermined range of values for the temperature and the pressure drop follows a decreasing pattern similar to the trend shown in the graph of FIG. 6.

[0304] The method further comprises applying a purge air flow through the air flow channel to remove generated aerosol and other contaminants from the airflow channel which might impact future results. In some embodiments, the purge air flow is applied between each individual puff, at the end of the predetermined time of step 404 as described above. In other embodiments, the purge air flow is applied at the end of a usage session (i.e. after 10 subsequent puffs have been carried out). The step of applying a purge air flow comprises applying that purge air flow for 28 seconds.

[0305] Applying a purge air flow comprises configuring the testing apparatus 100 to be in a second configuration, as shown in FIG. 7. To do this, the controller of the testing apparatus 100 closes the first valve 112 and the third valve 130 and opens the second valve 116 and the fourth valve 134. If the valves are already in their respective closed or open state for the second configuration, the controller is configured to maintain the valves in that state. For example, if the first valve 112 is already closed, the controller maintains the first valve in that closed position.

[0306] The controller is also configured to turn on the second pump 136 into its blowing mode to draw air through the airflow channel in a second direction which is opposite to the first direction such that air is drawn through the airflow channel 102 so as to flow from the second junction 113 towards the first junction 108. The flow of air is represented by dotted arrows in FIG. 7.

[0307] Air is not able to enter the airflow channel 102 through the first or third channel openings 105, 124 because the first and third valves 112, 130 are closed. Thus, when the second pump 136 draws air through the airflow channel 102 in the second direction, that air must be drawn into the airflow channel 102 through the fourth channel opening 128. The air that is drawn into the airflow channel 102 is fresh air that passes through the airflow channel 102, including through the sensing assembly 118. This fresh air flushes out any lingering aerosol or contaminants in the airflow channel 102. Any lingering aerosol or contaminants are entrained in the airflow and carried out of the airflow channel 102 through the second channel opening 107.

[0308] Applying a purge airflow further comprises configuring the testing apparatus 100 to be in a third configuration, as shown in FIG. 8. To do this, the controller of the testing apparatus 100 closes the first valve 112 and the third valve 130 and opens the second valve 116 and the fourth valve 134. As the valves are already in their respective closed or open state for the third configuration, when starting in the second configuration, the controller is configured to maintain the valves in that state. For example, the first valve 112 is already closed, so the controller maintains the first valve in that closed position.

[0309] The controller is also configured to turn on the second pump 136 into its suction mode to draw air through the airflow channel in the first direction such that air is drawn through the airflow channel 102 so as to flow from the first junction 108 towards the second junction 113. The flow of air is represented by the dotted lines in FIG. 8.

[0310] Air is not able to enter the airflow channel 102 through the first or third channel openings 105, 124 because the first and third valves 112, 130 are closed. Thus, when the second pump 136 draws air through the airflow channel 102 in the first direction, that air must be drawn into the airflow channel 102 through the second channel opening 107. The air that is drawn into the airflow channel 102 is fresh air that passes through the airflow channel 102, including through the sensing assembly 118. This fresh air flushes out any lingering aerosol or contaminants in the airflow channel 102. Any lingering aerosol or contaminants are entrained in the airflow and carried out of the airflow channel 102 through the second channel opening 107.

[0311] In the above described embodiment, a purge air flow is applied in two different directions in two different configurations of the testing apparatus. In some embodiments, applying a purge airflow only comprises applying the air flow in a single direction and in a single configuration of the testing apparatus.

[0312] The testing apparatus 100 has been described in combination with a first aerosol-generating system 200 of the type that receives and electrically heats an aerosol-generating article comprising an aerosol-forming substrate. However, it will be appreciated that the testing apparatus 100, or a similar testing apparatus 100, can be used with other types of aerosol-generating system provided that the aerosol-generating system comprises a mouthpiece through which, in normal use of the aerosol-generating system, a user of the system inhales.

[0313] For example, in some embodiments, the aerosol-generating system is of the type comprising an aerosol-generating device and a cartridge containing an aerosol-forming substrate. The aerosol-generating device may receive the cartridge in a cavity. Either the aerosol-generating device or the cartridge comprises a mouthpiece and that mouthpiece is received in the mouthpiece receiving portion of the testing apparatus 100. The aerosol-generating system is activated either by a user or automatically in response to detecting a user puff. The aerosol generated by the aerosol-generating device is then carried out in the same way as described above.

[0314] In other embodiments, the aerosol-generating system consists of an aerosol-generating article. The aerosol-generating article comprises a mouthpiece, an aerosol-forming substrate and a combustible carbonaceous heat source. The mouthpiece of the article is received in the mouthpiece receiving portion of the first channel opening 105. The aerosol-generating system is activated by igniting the combustible carbonaceous heat source. The aerosol generated by the aerosol-generating device is then carried out in the same way as described above. Because the pump assembly 138 mimics user puffs in the first configuration, the aerosol-generating article will combust (and so operate) in the same way as when used in a normal usage session.

[0315] In embodiments where the same testing apparatus 100 is used for different types of aerosol-generating system, the mouthpiece receiving portion of the first channel opening 105 is removable. In this way, the mouthpiece receiving portion can, if necessary, be removed and replaced with a mouthpiece receiving portion that is specifically shaped for the aerosol-generating system to be analysed.

[0316] A second embodiment of a testing apparatus 600 is shown in FIG. 9. The testing apparatus 600 of the second embodiment operates similarly to the testing apparatus of the first embodiment, as shown in FIG. 1. Like components are numbered accordingly. The testing apparatus 600 of the second embodiment differs in that is suitable for testing more than one aerosol-generating system 200 at once. Therefore, the testing apparatus 600 comprises two first channel openings 105, two first valves 112, two first branches 104 of air flow channel and two sensing assemblies 118. The airflow channel 102 and the above mentioned components are positioned and configured such that a single pump assembly 138 is used to draw air through the airflow channel in both the first and second directions. The first valves are controlled in unison. So, in the first configuration of the testing apparatus 600, both the first valves 112 are open and the single second valve 116 is closed. Air drawn in the first direction by the first pump 132 will therefore draw aerosol generated by both of the aerosol-generating systems into the airflow channel. As shown in FIG. 9, the airflow channel 102 is configured such that the aerosol from one of the aerosol-generating systems is drawn past one of the sensing assemblies 118 and the aerosol from the other of the aerosol-generating systems is drawn past the other of the sensing assemblies 118. In this way, aerosol generated by multiple aerosol-generating systems can be analysed separately and simultaneously.

[0317] The analysis of characteristics of the generated aerosol is as described above in relation to the testing apparatus 100.

[0318] In the second and third configurations of the testing apparatus 600, both of the first valves 112 are closed and the second valve 116 is opened. Therefore, purge air can be drawn through the airflow channel by the single pump assembly 138 in the same way as described in relation to the testing apparatus 100. As shown in FIG. 9, the airflow channel 102 is configured such that the purge airflow will pass through both sensor assemblies.

[0319] The testing apparatus 600 is designed for testing two aerosol-generating systems 200 simultaneously. However, it will be appreciated that the testing apparatus can be adapted for testing any number of aerosol-generating system 200 according in a similar way to testing the two aerosol-generating systems 200 as shown in FIG. 9.

[0320] A third embodiment of a testing apparatus 700 is shown in FIG. 10. The testing apparatus 700 of the third embodiment operates similarly to the testing apparatus of the first embodiment, as shown in FIG. 1. Like components are numbered accordingly.

[0321] The third embodiment of the testing apparatus 700 is another embodiment that is suitable for testing more than one aerosol-generating system at once, in particular two aerosol-generating systems. The testing apparatus 600 comprises two first channel openings 105 and two first branches 104 of air flow channel. The testing apparatus 700 also comprises two second channel openings 107 and two second branches 106 of airflow channel. Unlike the testing apparatus 600 of the second embodiment, the testing apparatus 700 of the third embodiment comprises a single sensor assembly 118.

[0322] The first and second branches 104 and 106 are connected to the sensor assembly through a rotatory valve mechanism 702. The rotatory valve mechanism 702 comprises a single opening 704 which is formed in a rotating disk 706, the rotating disk 706 being rotatable by an electrical motor of the rotatory valve mechanism, not shown in the Figures.

[0323] The rotatory valve mechanism 702 further comprises an airflow channel portion 708 for each of the first and second branches 104, 106. Each airflow channel portion 708 is connected to a central column 710. An airflow channel portion 712 connects the central column 710 to the sensor assembly 118.

[0324] In FIG. 10, the rotating disk 706 is positioned such that the single opening 704 is aligned with one of the first branches 104. In this way, the aerosol-generating system received in one of the first channel openings 105 can be tested by drawing generated aerosol through the sensor assembly 118 using the pump assembly 138, as described in relation to the first embodiment. The generated aerosol will be drawn through the first branch 104, into the central column 710 and then through airflow channel 712 before passing the sensor assembly 118 and on towards the pump assembly 138.

[0325] Because the rotating disk 706 only comprises a single opening 704, when the disk is positioned as shown in FIG. 10, the other branches are not engaged to the sensor assembly. In other words, only one of the first channel openings is open in FIG. 10, and both of the second channel opening are closed.

[0326] The rotating disk 706 can be controlled to be rotated by the electrical motor to connect different first or second branches (and associated first or second openings) to the sensor assembly and pump assembly.

[0327] FIG. 11 shows the rotating disk 706 in a second position in which the single opening 704 is aligned with one of the second branches 106 to connect one of the second channel openings to the sensor assembly 118 and pump assembly 138. In this position, a purge airflow can be applied through the sensor assembly, as described in relation to the first embodiment.

[0328] During operation of the testing apparatus 700, the rotating disk 706 is rotated so that the single opening 704 engages each of the first and second branches sequentially so as to draw aerosol from each aerosol-generating system past the sensor assembly and then perform a purge routine between drawing aerosol from an aerosol-generating system.

[0329] Unlike the testing apparatus 600 of the second embodiment, the testing apparatus 700 of third embodiment is not capable of simultaneous analysis of the aerosol generated by multiple aerosol-generating systems. Instead, the rotating disk 706 is rotated stepwise.

[0330] Of course, it is possible for the testing apparatus 700 to be configured to analyse more than two aerosol-generating systems. In that case, additional first and second channel openings and related features would be provided.