Aerosol-generating device with a first airflow passage and a second airflow passage

Abstract

An aerosol-generating device (100), comprising: a housing (20); an air inlet (17), an air outlet (18), and a first airflow passage extending within the housing (20) from the air inlet (17) to the air outlet (18), a pressure sensor (500) within the housing, the pressure sensor having: a first pressure sensing element (501) positioned in a first chamber and in fluid communication with the first airflow passage; and a second pressure sensing element (502) positioned in a second chamber, the second chamber being in fluid communication with a second airflow passage and sealed from the first chamber and the first airflow passage; and wherein the aerosol-generating device (100) further comprises an air release outlet (275, 276) in fluid communication with the second airflow passage for coupling the second chamber to an environment external to the aerosol-generating device.

Description

[0001] AEROSOL-GENERATING DEVICE WITH A FIRST AIRFLOW PASSAGE AND A SECOND AIRFLOW PASSAGE

[0002] The present specification relates to an aerosol-generating device for heating an aerosol-forming substrate to generate an aerosol. Particularly, but not exclusively, the invention relates to an aerosol-generating device comprising a synchronizing air flow path within the aerosol-generating device. The synchronizing path ensures a synchronised pressure between the external environment and the internal environment of the aerosolgenerating device.

[0003] In a number of handheld aerosol-generating devices, an electronic pressure sensor may be used to detect when or how a user is using the aerosol-generating device. For example, the electronic pressure sensor may be configured to detect a “puff action” when the user begins puffing on the aerosol-generating device. During a puff action, air from the environment external to the aerosol-generating device flows into the aerosol-generating device. This influx of air temporarily increases the internal pressure of the aerosol-generating device. The increase in the internal pressure is detected by the pressure sensor as a “puff action”. When the electronic pressure sensor detects a puff action, it usually sends a signal to a controller which then activates other components of the aerosol-generating device, such as the heating element which heats the aerosol-forming substrate to form an aerosol.

[0004] A number of handheld aerosol-generating devices also comprise a differential pressure sensor that that measures a relative change in internal pressure due to the influx of air from the external environment, during puff action. Differential pressure sensors can suffer from a phenomenon known as false triggering due to various reasons. False triggering can have many undesirable effects such as battery depletion, overheating of the aerosolgenerating device, and incorrect performance of the aerosol-generating device. It would therefore be desirable to provide an aerosol-generating device which does not or is less likely to suffer from such problems.

[0005] According to an aspect of the present invention, there is provided an aerosolgenerating device, comprising: a housing; an air inlet, an air outlet, and a first airflow passage extending within the housing from the air inlet to the air outlet, a pressure sensor within the housing, the pressure sensor having: a first pressure sensing element positioned in a first chamber and in fluid communication with the first airflow passage; and a second pressure sensing element positioned in a second chamber, the second chamber being in fluid communication with a second airflow passage and sealed from the first chamber and the first airflow passage; and wherein the aerosol-generating device further comprises an air release outlet in fluid communication with the second airflow passage for coupling the second chamber to an environment external to the aerosol-generating device. With an aerosol-generating device of the type of the first aspect of the invention, there may be various reasons for providing the device with a pressure sensor having: a first pressure sensing element positioned in a first chamber and in fluid communication with the first airflow passage; and a second pressure sensing element positioned in a second chamber, the second chamber being in fluid communication with a second airflow passage and sealed from the first chamber. For example, the inventors have found that such arrangements are known to improve the sensitive and accuracy of measurement for the pressure sensors. However, the present inventors have also found that such arrangement could lead to problems in the performance of the pressure sensor. For example, changes within the internal pressure within the housing can be unintentionally detected by the pressure sensor. For example, if an external force is applied onto the housing, the internal pressure within the housing may increase and this increase in the internal pressure may be detected by the pressure sensor. Where the pressure sensor (such as a puff sensor) is used to detect one or more parts of a puff action so as to control the use of a heating element, the detection of such altered conditions (such as an increase in pressure) by the pressure sensor may trigger unintentional activation of the heating element.

[0006] By providing an air release outlet in fluid communication with the second air flow passage for coupling the second chamber to an environment external to the aerosolgenerating device, such adverse effects can be avoided or mitigated. In particular, the second airflow passage and air release outlet can provide a means for preventing activity occurring within the housing from influencing the performance of the pressure sensor. For example, the second airflow passage and air release outlet can prevent an increase in pressure occurring at the pressure sensor in response to an increase in pressure within the housing, because air can be pushed out of the housing via the second airflow passage and air release outlet to stabilise the internal pressure within the housing. The construction of the device of the first aspect may therefore, in some embodiments, be able to provide an internal air flow pathway that ensures a synchronised pressure between the external environment and the internal environment of the aerosol-generating device when the aerosol-generating device is not being used.

[0007] As used herein, the term “pressure sensor” may refer to any suitable sensing means for sensing one or more signals one or more signals indicative of an change in pressure within the aerosol-generating device.

[0008] As used herein, the term “first surface of the pressure sensor” relates to a component of the pressure sensor, for instance, a deformable membrane suitable for sensing one or more signals indicative of a change in pressure. As used herein, the term “air inlet” refers to an opening in the housing of the aerosolgenerating device that allows air from the external environment to flow into the aerosolgenerating device during a puff action.

[0009] As used herein, the term “air outlet” refers to an opening in the housing of the aerosolgenerating device which allows aerosol to flow out of the aerosol-generating device during a puff action.

[0010] As used herein, the term “air release outlet” refers to an opening in the housing of the aerosol-generating device that allows air to be released from within the aerosol-generating device to the external environment.

[0011] The air inlet may be a first air inlet and the aerosol-generating device may further comprises one or more second air inlets in a plurality of air inlets. This may advantageously allow more air to flow into the aerosol-generating device during a puff action, which may result in greater amount of aerosol production.

[0012] The air release outlet may be a first air release outlet and the aerosol-generating device may further comprises one or more second air release outlets in a plurality of air release outlets. This may advantageously provide a lower resistance to the flow of air outside the aerosol-generating device, which may enhance the prevention of air being drawn into the aerosol-generating device whilst the device is not being used.

[0013] The housing may comprise a mouthpiece for delivering aerosol to a user. The mouthpiece may comprises the air outlet. The air outlet may be in fluid communication with the mouthpiece.

[0014] The aerosol-generating device may comprise a plurality of components within the housing, the plurality of components including the pressure sensor.

[0015] The first pressure sensing element may be configured to measure a pressure Pi that characterises the pressure in the first air flow passage, and wherein the second pressure sensing element may be configured to measure a pressure P2 that characterises the pressure in the second air flow passage. This may advantageously measure the relative pressure of the air flowing through the first air flow passage when compared to the ambient pressure inside the aerosol-generating device. This may advantageously provide an increased sensitivity and precision for determining a puff action.

[0016] The aerosol-generating device may further comprises a battery, wherein the battery is configured to supply power to at least the pressure sensor within the housing.

[0017] The aerosol-generating device may further include a plurality of wires, wherein the plurality of wires are configured to connect to at least the pressure sensor within the housing. The plurality of wires advantageously facilitate an electrical connection between the pressure sensor and the control circuitry. The housing may comprises a housing wall. The housing wall may further comprise an external surface and an internal surface. The external surface of the housing wall may form the external surface of the housing. The internal surface of the housing wall may form the internal surface of the housing.

[0018] The internal surface of the housing wall may define an internal volume of the housing.

[0019] The air inlet may extend through the housing from the external surface of the housing wall to the internal surface of the housing wall.

[0020] The air release outlet may extend through the housing from the external surface of the housing wall to the internal surface of the housing wall.

[0021] The housing wall may be a housing side wall, and wherein the air release outlet may extend from an external surface of the housing side wall to an internal surface of the housing side wall.

[0022] The air release outlet may extend along a periphery of the housing side wall, from the external surface of the housing side wall to the internal surface of the housing side wall.

[0023] The air release outlet may extend along at least 2 percent, preferably at least 10 percent, more preferably at least 20 percent, even more preferably at least 40 percent of the perimeter of the housing side wall.

[0024] The housing wall may further comprise a housing bottom wall, and wherein the air release outlet may be positioned at a location proximate the housing bottom wall.

[0025] The housing may comprise a first housing component and a second housing component. The first housing component may define a first end of the housing. The second housing component may define a second end of the housing. This may advantageously simplify the manufacturing process of the aerosol-generating device.

[0026] The air inlets may be part of the first housing component. The air release outlets may be part of the second housing component.

[0027] The second housing component may comprise peripheral perforations configured to form the air release outlet.

[0028] The air release outlet may extend along at least a portion of the periphery of the second housing component.

[0029] The air release outlet may extend along at least 2 percent, preferably at least 10 percent, more preferably at least 20 percent, even more preferably at least 40 percent of the perimeter of the second housing component. This may advantageously allow for more air within the aerosol-generating device to escape through the air release outlet, resulting in a quicker stabilisation of the internal pressure within the housing of the aerosol-generating device.

[0030] The second housing component may be configured to engage with the first housing component, such that an interstice is present between the first housing component and the second housing component, and wherein the interstice is in fluid communication with an environment external to the aerosol-generating device.

[0031] The second housing component may be configured to engage with the first housing component at the second end of the housing, such that an interstice is present between the first housing component and the second housing component, and wherein the interstice is in fluid communication with an environment external to the aerosol-generating device.

[0032] The interstice may be a gap between a side wall of the first housing component and a side wall of the second housing component.

[0033] The air inlets may be part of the first housing component, and the air release outlets may be part of the second housing component and, the interstice may be in fluid communication with the second airflow passage by way of the interstice being in fluid communication with the air release outlet.

[0034] The air inlets may be part of the first housing component and wherein the interstice may form the air release outlet in fluid communication with the second airflow passage.

[0035] The interstice may be no more than 0.2mm.

[0036] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0037] EX 1 : An aerosol-generating device, comprising: a housing; an air inlet, an air outlet, and a first airflow passage extending within the housing from the air inlet to the air outlet, a pressure sensor within the housing, the pressure sensor having: a first pressure sensing element positioned in a first chamber and in fluid communication with the first airflow passage; and a second pressure sensing element positioned in a second chamber, the second chamber being in fluid communication with a second airflow passage and sealed from the first chamber and the first airflow passage; and wherein the aerosol-generating device further comprises an air release outlet in fluid communication with the second airflow passage for coupling the second chamber to an environment external to the aerosol-generating device.

[0038] EX 2: The aerosol-generating device according to EX 1 wherein the air inlet is a first air inlet and the aerosol-generating device further comprises one or more second air inlets in a plurality of air inlets

[0039] EX 3: The aerosol-generating device according to any of EX 1 or EX 2 wherein the air release outlet is a first air release outlet and the aerosol-generating device further comprises one or more second air release outlets in a plurality of air release outlets. EX 4: The aerosol-generating device according to any preceding EX, wherein the housing comprises a mouthpiece for delivering aerosol to a user.

[0040] EX 5: The aerosol-generating device according to EX 4, wherein the mouthpiece comprises the air outlet.

[0041] EX 6: The aerosol-generating device according to EX 5, wherein the air outlet is in fluid communication with the mouthpiece.

[0042] EX 7: The aerosol-generating device according to any preceding EX, wherein the device comprises a plurality of components within the housing, the plurality of components including the pressure sensor.

[0043] EX 8: The aerosol-generating device according to any preceding EX, wherein the first pressure sensing element is configured to measure a pressure Pi that characterises the pressure in the first air flow passage, and wherein the second pressure sensing element is configured to measure a pressure P2 that characterises the pressure in the second air flow passage.

[0044] EX 9: The aerosol-generating device according to any EX, wherein the aerosol-generating device further comprises a battery, wherein the battery is configured to supply power to at least the pressure sensor within the housing.

[0045] EX 10: The aerosol-generating device according to any preceding EX, wherein the aerosol-generating device further includes a plurality of wires, wherein the plurality of wires are configured to connect to at least the pressure sensor within the housing.

[0046] EX 11 : The aerosol-generating device according to any preceding EX, wherein the housing comprises a housing wall, wherein the housing wall further comprises an external surface and an internal surface, and wherein the external surface of the housing wall forms the external surface of the housing and wherein the internal surface of the housing wall forms the internal surface of the housing.

[0047] EX 12: The aerosol-generating device according to EX 11 , wherein the internal surface of the housing wall defines an internal volume of the housing.

[0048] EX 13: The aerosol-generating device according to any of EX 11 to 12, wherein the air inlet extends through the housing from the external surface of the housing wall to the internal surface of the housing wall.

[0049] EX 14: The aerosol-generating device according to any of EX 12 to 13, wherein the air release outlet extends through the housing from the external surface of the housing wall to the internal surface of the housing wall.

[0050] EX 15: The aerosol-generating device according to any of EX 11 to EX 14, wherein the housing wall is a housing side wall, and wherein the air release outlet extends from an external surface of the housing side wall to an internal surface of the housing side wall. EX 16: The aerosol-generating device according to EX 15, wherein the air release outlet may extend along a periphery of the housing side wall, from the external surface of the housing side wall to the internal surface of the housing side wall.

[0051] EX 17: The aerosol-generating device according to EX 16, wherein the air release outlet extends along at least 2 percent, preferably at least 10 percent, more preferably at least 20 percent, even more preferably at least 40 percent of the perimeter of the housing side wall.

[0052] EX 18: The aerosol-generating device according to any of EX 11 to EX 17, wherein the housing wall further comprises a housing bottom wall, and wherein the air release outlet is positioned at a location proximate the housing bottom wall.

[0053] EX 19: The aerosol-generating device according to any preceding EX, wherein the housing comprises a first housing component and a second housing component, wherein the first housing component defines a first end of the housing, and wherein the second housing component defines a second end of the housing.

[0054] EX 20: The aerosol-generating device according to EX 19, wherein the air inlets are part of the first housing component, and wherein the air release outlets are part of the second housing component.

[0055] EX 21 : The aerosol-generating device according to EX 20, wherein the second housing component comprises peripheral perforations configured to form the air release outlet.

[0056] EX 22: The aerosol-generating device according to EX 21 , wherein the air release outlet extends along at least a portion of the periphery of the second housing component.

[0057] EX 23: The aerosol-generating device according to EX 22, wherein the air release outlet extends along at least 2 percent, preferably at least 10 percent, more preferably at least 20 percent, even more preferably at least 40 percent of the perimeter of the second housing component.

[0058] EX 24: The aerosol-generating device according to any of EX 19 to 23, wherein the second housing component engages with the first housing component, such that an interstice is present between the first housing component and the second housing component, and wherein the interstice is in fluid communication with an environment external to the aerosolgenerating device.

[0059] EX 25: The aerosol-generating device according to any of EX 19 to EX 23, wherein the second housing component engages with the first housing component at the second end of the housing, such that an interstice is present between the first housing component and the second housing component, and wherein the interstice is in fluid communication with an environment external to the aerosol-generating device. EX 26: The aerosol-generating device according to EX 24 or 25, wherein the air inlets are part of the first housing component, and wherein the air release outlets are part of the second housing component and, wherein the interstice is in fluid communication with the second airflow passage by way of the interstice being in fluid communication with the air release outlet.

[0060] EX 27: The aerosol-generating device according to EX 26, wherein the air inlets are part of the first housing component and wherein the interstice forms the air release outlets in fluid communication with the second airflow passage.

[0061] EX 28: The aerosol-generating device according to any of EX 24 to 27, wherein the interstice is no more than 0.2mm.

[0062] EX 29: The aerosol-generating device according to any of EX24 to EX 28, wherein the interstice is a gap between a side wall of the first housing component and a side wall of the second housing component.

[0063] EX 30: The aerosol-generating device according to any preceding EX, wherein the aerosol-generating device comprises an assembly within the housing of the aerosolgenerating device.

[0064] EX 31 : The aerosol-generating device according to EX 30 when dependent on any of EX 19 to 29, wherein the aerosol-generating device comprises an assembly within the first component of the housing of the aerosol-generating device.

[0065] EX 32: The aerosol-generating device according to EX 30 or 31 , wherein the assembly is configured house and protect at least the pressure sensor of the aerosol-generating device.

[0066] EX 33: The aerosol-generating device according to any of EX 30 to 32, wherein the assembly is configured to provide mechanical protection to the pressure sensor housed within the assembly of the aerosol-generating device.

[0067] EX 34: The aerosol-generating device according to any of EX 30 to 33, wherein the assembly defines the first chamber in fluid communication with the first airflow passage and the second chamber in fluid communication with the second airflow passage.

[0068] EX 35: The aerosol-generating device according to EX 34, wherein the first chamber comprises a first chamber opening and wherein the second chamber comprises a second chamber opening, wherein the first pressure sensing element is in fluid communication with the first airflow passage through the first chamber opening, and wherein the second pressure sensing element is in fluid communication with the second airflow passage through the second chamber opening.

[0069] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0070] Figure 1 is a schematic view of an aerosol-generating device according to an embodiment of the present invention; Figure 2 is a schematic view of the second housing component of the aerosolgenerating device of Figure 1 ;

[0071] Figure 3 is a schematic view of the aerosol-generating device of Figure 1 , showing the air flow path through the first airflow passage and through the first chamber opening; and

[0072] Figure 4 is also a schematic view of the aerosol-generating device of Figure 1 , showing the air flow path within the second airflow passage and through the air release outlet.

[0073] Figure 1 shows an aerosol-generating device 100 according to a first embodiment comprising a mouthpiece 10 for use with the aerosol-generating device. The aerosolgenerating device 100 comprises a liquid storage portion 12 containing a liquid-aerosol forming substrate for use with the aerosol-generating device 100. The liquid storage portion 12 is configured to deliver liquid aerosol-forming substrate to the heating element 15. As the user puffs on the mouthpiece 10, an air supply is drawn into the aerosol-generating device 100 through the air inlets 17. The air supply at an ambient temperature condenses the vapour to form a stream of generated aerosol. The mouthpiece 10 comprises an air outlet 18 and as the user puffs on the mouthpiece 10, the stream of generated aerosol may exit the device through the air outlet 18. As such, the aerosol-generating device 100 comprises a first air flow passage extending between the air inlets 17 and the air outlet 18, wherein, the first airflow passage is configured to deliver generated aerosol to the user.

[0074] The aerosol-generating device 100 comprises a housing 20. The housing comprises a housing wall 21 which further comprises an external surface 212 and an internal surface 211. The external surface 212 of the housing wall forms the external surface of the housing 20. The internal surface 211 of the housing wall forms the internal surface of the housing 20. The internal surface of the housing wall also defines an internal volume of the housing. The air inlets 17 extend through the housing wall 20 from the external surface 212 of the housing wall to the internal surface 211 of the housing wall.

[0075] The second housing component 30 of the aerosol-generating device 100 is also shown in Figure 1. A first end of the second housing component comprises a sealing edge 309 configured to engage with the inner wall 211 of the housing to create a tight fitting interference fit. The second housing component also comprises an opening 311 at the first end of the second housing component. The second housing component 30 is configured to be in fluid communication with the first air flow passage extending within the housing 20, through the opening 311 in the second housing component 30. The second housing component 30 also comprises a sealing edge 310 at a second end of the second housing component, wherein the sealing edge 310 is also configured to engage the inner wall 211 of the housing 20, at a second end of the housing 20, to create a tight-fitting interference fit. The second housing component 30 comprises peripheral perforations 271 , 272 at the second end of the second housing component 30. The engagement between the second housing component 30 and the housing 20, at the second end of the housing 20, is configured such that an interstice 275, 276 is present. The interstice is configured to form the air release outlet.

[0076] As show in Figure 2, the aerosol-generating device 100, also comprises a plurality of components within the second housing component 30. The plurality of components including the pressure sensor 500. The pressure sensor 500 is a differential pressure sensor and is configured to be positioned within a chamber 503 of the second housing component 30. The pressure sensor has a first pressure sensing surface 501 that is configured to measure a pressure P1 that characterises the pressure of the air flowing through the first air flow passage. The pressure sensor also has a second pressure sensing surface 502 that is configured to measure a pressure P2 that characterises the internal pressure within the housing 30 of the aerosol-generating device. The pressure sensor is electrically connected to the Printed Circuit Board (PCB) 504 through electrical connections 541 , 542. The PCB is positioned adjacent to the chamber 503 and comprises a small opening 507 that aligns with a chamber opening 508. The chamber also has a second chamber opening 509 opposite the first pressure sensing surface 501. The first pressure sensing surface 501 , of the pressure sensor 500, is configured to be in fluid communication with the first air flow passage through the chamber opening 509. The second surface of the pressure sensor 502 is configured to be in fluid communication with the internal environment within the housing through the PCB opening 507 and the chamber opening 508.

[0077] The differential pressure sensor 500 is configured to measure a relative change in pressure by measuring a pressure change between P1 and P2. That is, the first surface of the pressure sensor 501 is configured to measure the pressure P1 of the air flow in the first air flow passage. The second surface of the pressure sensor is configured to measure a pressure P2 of the second housing component and the second airflow passage. Therefore, a change in pressure P1 relative to the pressure P2, detected by the differential pressure sensor 500 can “trigger” the PCB to record a puff action. When the PCB does this, other components of the device such as the heating element are activated. For example, the first pressure sensing surface 501 , of the pressure sensor 500, comprises a deformable membrane that is configured to deforms when there is a change in pressure inside the chamber 503, due to a change in pressure during a “puff action”.

[0078] As shown in Figures 1 and 2, the aerosol-generating device 100 comprises an electrical energy supply 306, for example a lithium ion battery. The electrical energy supply 306 is configured to supply power to the electrical components of the device 100 such as the PCB 504 and the pressure sensor 500.

[0079] Figure 3 shows the events that occur to cause a change in pressure within the aerosolgenerating device 100 of Figure 1 , during a “puff action”. During a “puff action”, the change in pressure is caused when the user puffing through the mouthpiece 10 of the aerosol-generating device 100. When this happens, air from the external environment flows into the housing 20 of the aerosol generating device through the air inlets 17. As illustrated by the dashed arrows in Figure 3, a portion of the air flows through the first air flow passage, extending from the air inlets 17 to the air outlet 18 in the mouthpiece. Simultaneously, air is also configured to flow into the second housing component 30, through the opening 311 in the second housing component. The air flowing through the opening 311 in the second housing component is configured to be in fluid communication with the first pressure sensing surface 501 of the pressure sensor 500, through the chamber opening 509. This air flow is detected by the pressure sensor and “triggers” the PCB to record a puff action. When the PCB does this, other components of the device such as the heating element are activated or otherwise controlled.

[0080] The second pressure sensing surface 502 within the second housing component 30 is sealed from the first pressure sensing surface 501 through sealing elements 511 , 512. The internal pressure within the second housing component 30 can change even when the aerosol-generating device 100 is not in use, i.e. when the user is not puffing on the aerosolgenerating device.

[0081] The internal pressure within the second housing component 30 can vary due to various reasons, for instance by placing the device in a low pressure environment or when an external pressure is applied to the housing of 20 of the device 100. Therefore, a change in the internal pressure within the second housing component 30 can cause the deformable membranes of the pressure sensor 500 to deform, resulting in the pressure sensor detecting a “puff action” even when the user is not puffing. This is known as a “false trigger”.

[0082] When there is a change in the internal pressure within the second housing component when the aerosol-generating device is not in use, for instance, if the internal pressure increases due to an external force applied onto the housing 20, the ambient air at the first pressure sensing surface 501 can escape through the aerosol-generating device 100 through the opening 311 of the second housing component, and consequently through the air inlets 17, to stabilise the internal pressure at the first pressure sensing surface 501. Likewise, if the internal pressure decreases, for instance, due to placing the device 100 in a low pressure environment, ambient air, outside the device 100, can flow into the second housing component through the air inlets 17, and consequently through the opening 311 of the second housing component to stabilise the internal pressure at the first pressure sensing surface 501. This stabilisation of the internal pressure at the first pressure sensing surface 501 prevents the pressure sensor from experiencing a “false trigger” and recording a puff action when the aerosol-generating device 100 is not in use.

[0083] As illustrated by the dashed arrows in Figure 4, when there is a change in the internal pressure within the second housing component when the aerosol-generating device is not in use, for instance, if the internal pressure increases due to an external force applied onto the housing 20, the ambient air at the second pressure sensing surface 502 can escape the aerosol-generating device 100 through the opening 209 of the second housing component, and consequently through the openings 275, 276 of the air release outlet , to stabilise the internal pressure at the second pressure sensing surface 501. Likewise, if the internal pressure decreases, for instance, due to placing the device 100 in a low pressure environment, ambient air, outside the device 100, can flow into the second housing component through the openings 275, 276 of the air release outlet, and consequently through the opening 209 of the second housing component to stabilise the internal pressure at the second pressure sensing surface 502. This stabilisation of the internal pressure at the second pressure sensing surface 502 prevents the pressure sensor from experiencing a “false trigger” and recording a puff action when the aerosol-generating device 100 is not in use.

[0084] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 10% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1. CLAIMS1. An aerosol-generating device, comprising: a housing; an air inlet, an air outlet, and a first airflow passage extending within the housing from the air inlet to the air outlet, a pressure sensor within the housing, the pressure sensor having: a first pressure sensing element positioned in a first chamber and in fluid communication with the first airflow passage; and a second pressure sensing element positioned in a second chamber, the second chamber being in fluid communication with a second airflow passage and sealed from the first chamber and the first airflow passage; and wherein the aerosol-generating device further comprises an air release outlet in fluid communication with the second airflow passage for coupling the second chamber to an environment external to the aerosol-generating device.

2. The aerosol-generating device according to claim 1 wherein the air inlet is a first air inlet and the aerosol-generating device further comprises one or more second air inlets in a plurality of air inlets.

3. The aerosol-generating device according to claim 1 or claim 2 wherein the air release outlet is a first air release outlet and the aerosol-generating device further comprises one or more second air release outlets in a plurality of air release outlets.

4. The aerosol-generating device according to any preceding claim, wherein the housing comprises a mouthpiece for delivering aerosol to a user.

5. The aerosol-generating device according to claim 4, wherein the mouthpiece comprises the air outlet.

6. The aerosol-generating device according to claim 5, wherein the air outlet is in fluid communication with the mouthpiece.

7. The aerosol-generating device according to any preceding claim, wherein the device comprises a plurality of components within the housing, the plurality of components including the pressure sensor.

8. The aerosol-generating device according to any preceding claim, wherein the first pressure sensing element is configured to measure a pressure Pi that characterises the pressure in the first air flow passage, and wherein the second pressure sensing element is configured to measure a pressure P2 that characterises the pressure in the second air flow passage.

9. The aerosol-generating device according to any preceding claim, wherein the aerosolgenerating device further comprises a battery, wherein the battery is configured to supply power to at least the pressure sensor within the housing.

10. The aerosol-generating device according to any preceding claim, wherein the aerosolgenerating device further includes a plurality of wires, wherein the plurality of wires are configured to connect to at least the pressure sensor within the housing.11 . The aerosol-generating device according to any preceding claim, wherein the housing comprises a housing wall, wherein the housing wall further comprises an external surface and an internal surface, and wherein the external surface of the housing wall forms the external surface of the housing and wherein the internal surface of the housing wall forms the internal surface of the housing.

12. The aerosol-generating device according to claim 11 , wherein the internal surface of the housing wall defines an internal volume of the housing.

13. The aerosol-generating device according to any of claims 11 to 12, wherein the air inlet extends through the housing from the external surface of the housing wall to the internal surface of the housing wall.

14. The aerosol-generating device according to any of claims 12 to 13, wherein the air release outlet extends through the housing from the external surface of the housing wall to the internal surface of the housing wall.

15. The aerosol-generating device according to any of claims 11 to 14, wherein the housing wall is a housing side wall, and wherein the air release outlet extends from an external surface of the housing side wall to an internal surface of the housing side wall.

16. The aerosol-generating device according to claim 15, wherein the air release outlet may extend along a periphery of the housing side wall, from the external surface of the housing side wall to the internal surface of the housing side wall.

17. The aerosol-generating device according to claim 16, wherein the air release outlet extends along at least 2 percent, preferably at least 10 percent, more preferably at least 20 percent, even more preferably at least 40 percent of the perimeter of the housing side wall.

18. The aerosol-generating device according to any of claims 11 to 17, wherein the housing wall further comprises a housing bottom wall, and wherein the air release outlet is positioned at a location proximate the housing bottom wall.

19. The aerosol-generating device according to any preceding claim, wherein the housing comprises a first housing component and a second housing component, wherein the first housing component defines a first end of the housing, and wherein the second housing component defines a second end of the housing.

20. The aerosol-generating device according to claim 19, wherein the air inlets are part of the first housing component, and wherein the air release outlets are part of the second housing component.

21. The aerosol-generating device according to claim 20, wherein the second housing component comprises peripheral perforations configured to form the air release outlet.

22. The aerosol-generating device according to claim 21 , wherein the air release outlet extends along at least a portion of the periphery of the second housing component.

23. The aerosol-generating device according to claim 22, wherein the air release outlet extends along at least 2 percent, preferably at least 10 percent, more preferably at least 20 percent, even more preferably at least 40 percent of the perimeter of the second housing component.

24. The aerosol-generating device according to any of claims 19 to 23, wherein the second housing component engages with the first housing component, such that an interstice is present between the first housing component and the second housing component, and wherein the interstice is in fluid communication with an environment external to the aerosolgenerating device.

25. The aerosol-generating device according to any of claims 19 to 23, wherein the second housing component engages with the first housing component at the second end of the housing, such that an interstice is present between the first housing component and the second housing component, and wherein the interstice is in fluid communication with an environment external to the aerosol-generating device.

26. The aerosol-generating device according to claim 24 or 25, wherein the air inlets are part of the first housing component, and wherein the air release outlets are part of the second housing component and, wherein the interstice is in fluid communication with the second airflow passage by way of the interstice being in fluid communication with the air release outlet.

27. The aerosol-generating device according to claim 26, wherein the air inlets are part of the first housing component and wherein the interstice forms the air release outlets in fluid communication with the second airflow passage.

28. The aerosol-generating device according to any of claim 24 to 27, wherein the interstice is no more than 0.2mm.

29. The aerosol-generating device according to any of claims 24 to 28, wherein the interstice is a gap between a side wall of the first housing component and a side wall of the second housing component.

30. The aerosol-generating device according to any preceding claim, wherein the aerosolgenerating device comprises an assembly within the housing of the aerosol-generating device.31 . The aerosol-generating device according to claim 30 when dependent on any of claims 19 to 29, wherein the aerosol-generating device comprises an assembly within the first component of the housing of the aerosol-generating device.

32. The aerosol-generating device according to claim 30 or 31 , wherein the assembly is configured house and protect at least the pressure sensor of the aerosol-generating device.

33. The aerosol-generating device according to any of claims 30 to 32, wherein the assembly is configured to provide mechanical protection to the pressure sensor housed within the assembly of the aerosol-generating device.

34. The aerosol-generating device according to any of claims 30 to 33, wherein the assembly defines the first chamber in fluid communication with the first airflow passage and the second chamber in fluid communication with the second airflow passage.

35. The aerosol-generating device according to claim 34, wherein the first chamber comprises a first chamber opening and wherein the second chamber comprises a second chamber opening, wherein the first pressure sensing element is in fluid communication with the first airflow passage through the first chamber opening, and wherein the second pressure sensing element is in fluid communication with the second airflow passage through the second chamber opening.

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