Aerosol-generating device with induction actuated airflow pump

Abstract

The invention relates to an aerosol-generating device comprising a substrate cavity for receiving an aerosol-forming substrate. Further, the aerosol-generating device comprises an induction actuated airflow pump. The pump is fluidly connected with the substrate cavity. The pump is configured to pump air into the substrate cavity. The invention further relates to a method of removing excess moisture in an aerosol-generating device.

Description

[0001] Philip Morris Products S.A.

[0002] -1-

[0003] AEROSOL-GENERATING DEVICE WITH INDUCTION ACTUATED AIRFLOW PUMP

[0004] The present invention relates to an aerosol-generating device. The invention further relates to a method of removing excess moisture in an aerosol-generating device.

[0005] It is known to provide an aerosol-generating device for generating an inhalable vapor. Such devices may heat aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate are volatilised without burning the aerosolforming substrate. Aerosol-forming substrate may be provided as part of an aerosolgenerating article. The aerosol-generating article may have a rod shape for insertion of the aerosol-generating article into a substrate cavity, such as a heating chamber, of the aerosolgenerating device. A heating element may be arranged in or around the heating chamber for heating the aerosol-forming substrate once the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device. In humid environments, an undesirable warm first puff may be created due to a high moisture content in the aerosol-generating substrate of the aerosol-generating article.

[0006] It would be desirable to have an aerosol-generating device preventing an undesirable warm first puff in humid environments.

[0007] According to an embodiment of the invention there may be provided an aerosolgenerating device comprising a substrate cavity for receiving an aerosol-forming substrate. Further, the aerosol-generating device may comprise an induction actuated airflow pump. The pump may be fluidly connected with the substrate cavity. The pump may be configured to pump air into the substrate cavity.

[0008] According to an embodiment of the invention there is provided an aerosol-generating device comprising a substrate cavity for receiving an aerosol-forming substrate. Further, the aerosol-generating device comprises an induction actuated airflow pump. The pump is fluidly connected with the substrate cavity. The pump is configured to pump air into the substrate cavity.

[0009] The pump enables the creation of an airflow in the substrate cavity. This airflow in the substrate cavity may create a pumping action in the substrate cavity. The airflow in the substrate cavity may be utilized to remove undesired humid air or aerosol from the substrate cavity. Particularly in humid environments, the aerosol-forming substrate of an aerosolgenerating article may have a humidity higher than usual. This may be particularly problematic if the pack of aerosol-generating articles is open for multiple hours before usage of an aerosol-generating article in the aerosol-generating device. Exemplarily, a user may insert a fresh aerosol-generating article into the substrate cavity. The aerosol-forming substrate of this aerosol-generating article may have a humidity that would lead to an undesired hot first puff as the increased humidity has to be removed from the aerosolforming substrate. During a preheating period, the present invention may enable to create a drawing or pumping effect in the substrate cavity and thus in the aerosol-generating article via the pump. The drawing or pumping effect can create an airflow through the aerosolforming substrate of the aerosol-generating article and thus remove the humid air / aerosol in the aerosol-generating article. After removal of the humid air / aerosol, a user can use the aerosol-generating article optimally without experiencing an undesired hot first puff.

[0010] The preheating phase of the aerosol-generating device may be signaled to a user. For example, an acoustic, haptic, or optical signal may be provided by the aerosol-generating device signaling the end of the preheating phase. A user may want to purge excess humidity from the substrate cavity when the aerosol-generating device is indicating an end of the preheating phase. Alternatively or additionally, the aerosol-generating device may be configured to produce an excess moisture purging signal during the preheating phase indicating to a user when to perform the pumping action.

[0011] The aerosol-generating device may comprise a humidity sensor in or adjacent the substrate cavity to determine the moisture of aerosol-forming substrate in the aerosolgenerating article. A controller of the aerosol-generating device may control the signal generation based upon the output of the moisture detector. Alternatively, the controller may be configured to perform an automatic excess moisture purging process depending upon the output of the moisture detector.

[0012] The aerosol-generating device may comprise a printed circuit board. The printed circuit board may control the pump.

[0013] The aerosol-generating device may comprise a main air inlet. During use, ambient air may be drawn via the main air inlet into the aerosol-generating device, preferably into the substrate cavity. An airflow channel may run through the substrate cavity. Ambient air may be drawn into the aerosol-generating device, into the substrate cavity and towards the user through the airflow channel. Downstream of the substrate cavity, a mouthpiece may be arranged or a user may directly draw on the aerosol-generating article. The airflow channel may extend through the mouthpiece.

[0014] The pump may be configured to pump ambient air drawn into the airflow channel in a downstream direction leading to a pumping action in the substrate cavity. The pump may be configured to pump ambient air drawn into the airflow channel in an upstream direction leading to a drawing action in the substrate cavity. Activation of the pump may lead to a pumping action followed by drawing action or vice versa.

[0015] The pump may be an induction actuated air flow pump. The pump may comprise a conductor surrounding or being surrounded by a movable magnet with a static magnetic field. Upon power supply to the conductor, a magnetic field may be generated around the conductor. The magnetic field may interact with the static magnetic field of the movable magnet. The interaction between the magnetic field of the conductor and the static magnetic field may result in a force acting upon the movable magnet. This resulting force may either be repulsive or attractive. The resulting force may be used to cause the displacement of the movable magnet within the pump. The movement of the movable magnet may generate an airflow from the ambient environment into the pump and from the pump into the substrate cavity.

[0016] The pump may comprise the movable magnet. The movable magnet may be received within the pump. The movable magnet may be a permanent magnet. The movable magnet may comprise a permanent magnet. The movable magnet may comprise a first and a second element. The first element may be a permanent magnet. The first element may be an electromagnet. The second element may be a non-magnetic element. The second element may be a ferromagnetic element. The first element comprising the permanent magnet may be mounted on the second element. The second element may be configured movable relative to the rest of the pump. The second element may be configured as one or more guiding elements as described in more detail below.

[0017] The movable magnet may comprise a third element. The movable magnet may comprise several elements.

[0018] The movable magnet may be movable relative to the substrate cavity. The movable magnet may be movable parallel to a longitudinal central axis of the substrate cavity.

[0019] The movable magnet may comprise a permanent magnet and one or more nonmagnetic elements. The movable magnet may comprise a permanent magnet and ferromagnetic elements. The permanent magnet may be enclosed in a magnetic structure. The magnetic structure may be ferromagnetic. The magnetic structure may amplify the static magnetic field generated by the permanent magnet. The magnetic structure may comprise or consist of a flux concentrator.

[0020] The pump may comprise an induction coil. The conductor may be configured as the induction coil. The pump may comprise the induction coil and the movable magnet. The induction coil may be arranged at least partly surrounding the movable magnet. The induction coil may be arranged fully surrounding the movable magnet. Alternatively, the movable magnet may be arranged at least partly surrounding an induction coil. The movable magnet may be arranged fully surrounding the induction coil.

[0021] The induction coil may be configured to inductively move the movable magnet upon power supply to the induction coil. Upon power supply to the induction coil a magnetic field is generated surrounding the induction coil. The magnetic field of the induction coil may interact with the static magnetic field of the movable magnet, which may result in displacement of the movable magnet. Preferably, an alternating current is supplied to the induction coil for creating an alternating magnetic field around the induction coil.

[0022] The substrate cavity of the aerosol-generating device may have an open end into which the aerosol-generating article is inserted. The open end may be a proximal end. The substrate cavity may have a closed end opposite the open end. The closed end may be the base of the substrate cavity. The closed end may be closed, except for the provision of air apertures arranged in the base. The base of the substrate cavity may be flat. The base of the substrate cavity may be circular. The base of the substrate cavity may be arranged upstream of the substrate cavity. The open end may be arranged downstream of the substrate cavity. The substrate cavity may have an elongate extension. The substrate cavity may have a longitudinal central axis. A longitudinal direction may be the direction extending between the open and closed ends along the longitudinal central axis. The longitudinal central axis of the substrate cavity may be parallel to the longitudinal axis of the aerosol-generating device.

[0023] The substrate cavity may be configured as a heating chamber. The substrate cavity may have a cylindrical shape. The substrate cavity may have a hollow cylindrical shape. The substrate cavity may have a shape corresponding to the shape of the aerosol-generating article to be received in the substrate cavity. The substrate cavity may have a circular crosssection. The substrate cavity may have an elliptical or rectangular cross-section. The substrate cavity may have an inner diameter corresponding to the outer diameter of the aerosol-generating article.

[0024] The pump may comprise a pumping cavity. The pumping cavity may define a volume. The pumping cavity may define a volume enclosed by the pump housing.

[0025] Alternatively, the pumping cavity may define a volume, in which air is compressed or expanded. The pumping cavity may define a volume, in which pump actuation occurs. The pumping cavity may be partially or fully sealingly encompassed by means of a sealing element as described in more detail below. The pumping cavity may additionally comprise further elements.

[0026] The pump may comprise at least one pumping cavity. The pump may comprise more than one pumping cavity. The pump may comprise multiple pumping cavities. The pumping cavity may comprise a first chamber. The pumping cavity may comprise a second chamber. The first chamber and the second chamber may be fluidly separated from each other. Alternatively, and preferred, a one-way valve may be arranged between the first chamber and the second chamber. The one-way valve may allow airflow from the second chamber into the first chamber. The one-way valve may prevent airflow from the first chamber into the second chamber. The first chamber may be fluidly connected with the substrate cavity. The second chamber may be fluidly separated from the substrate cavity, preferably by means of the one-way valve. The pumping cavity may be arranged at least partly surrounding the substrate cavity. The pumping cavity may be arranged fully surrounding the substrate cavity.

[0027] The pump may be arranged upstream of the substrate cavity. The pump may be arranged upstream of the substrate cavity, particularly proximal to the base of the substrate cavity. The pump may be arranged upstream of the substrate cavity, particularly adjacent to the base of the substrate cavity. The pump may be arranged proximal to the base of the substrate cavity, wherein a connection element may connect the pump to the base of the substrate cavity. The connection element may be part of the pump.

[0028] The pumping cavity may comprise a first end. The pumping cavity may comprise a second end. The second end may be arranged opposite to the first end. The first end of the pumping cavity may be connected to the base of the substrate cavity. The first end of the pumping cavity may be connected to the base of the substrate cavity via the connection element. The first end of the pumping cavity may be proximal to the base of the substrate cavity. The second end of the pumping cavity may be arranged on an opposite side of the pumping cavity, distal to the base of the substrate cavity.

[0029] The pump may comprise a first aperture for pressure equalization. The pump may comprise a second aperture for pressure equalization. The pump may comprise several apertures for pressure equalization. The first aperture and the second aperture may be arranged in the pump housing. The first aperture and the second aperture may be arranged at the first end of the pumping cavity. The first aperture and the second aperture may be arranged at the second end of the pumping cavity. One or both of the first aperture and the second aperture may allow ambient air to be drawn into the pump, preferably into the second chamber of the pump.

[0030] The pumping cavity may have a hollow cylindrical shape. The pumping cavity may have a hollow frustoconical shape. The pumping cavity may have a shape corresponding to the shape of the movable magnet to be received in the pumping cavity. The pumping cavity may have a circular cross-section. The pumping cavity may have an elliptical or rectangular cross-section. The pumping cavity may have a ring-shaped cross-section. The pumping cavity may have an inner diameter corresponding to an outer diameter of the substrate cavity. The pumping cavity may have a circular shape. The pumping cavity may have an annular shape. The pumping cavity may be tubular. The pumping cavity may be tubular and may preferably surround the substrate cavity.

[0031] The movable magnet may be received within the pump, preferably within the pumping cavity. The movable magnet may be configured to be movable within the pumping cavity. The movable magnet may be configured to be movable within the pumping cavity so as to move air through the pumping cavity. The movable magnet may act as a piston within the pumping cavity. The movable magnet may push air into the substrate cavity with each complete movement.

[0032] The pumping cavity may be fluidly connected to the substrate cavity. The pumping cavity may be fluidly connected to the substrate cavity via an airflow channel. The pumping cavity may be fluidly connected to the substrate cavity via an aperture. The pumping cavity may be fluidly connected to the substrate cavity via the connection element.

[0033] The pumping cavity may be fluidly connected with the substrate cavity via a first oneway valve. The first one-way valve may be arranged at a distal portion of the aerosolgenerating device. The first one-way valve may be arranged at a distal end of the aerosolgenerating device. The first one-way valve may be arranged within the substrate cavity. The first one-way valve may be arranged at the first end of the pumping cavity. The first one-way valve may be arranged at the second end of the pumping cavity. The first one-way valve may be arranged downstream of the pumping cavity.

[0034] The first one-way valve may allow airflow from the pumping cavity into the substrate cavity. The first one-way valve may prevent airflow from the substrate cavity into the pumping cavity. The first one-way valve may allow airflow from the pumping cavity into the substrate cavity in case of a pump actuation.

[0035] The pumping cavity may be fluidly connected with the ambient environment via a second one-way valve. The second one-way valve may be arranged within an air inlet of the aerosol-generating device. This air inlet may be configured as a pump air inlet. The pump air inlet may exclusively allow airflow into the pump. The second one-way valve may be arranged at a distal portion of the aerosol-generating device. The second one-way valve may be arranged at a distal end of the aerosol-generating device. The second one-way valve may be arranged upstream of the pumping cavity.

[0036] The second one-way valve may allow airflow from the ambient environment into the pumping cavity. The second one-way valve may prevent airflow from the pumping cavity into the ambient environment.

[0037] Movement of the movable magnet may pressurize the pumping cavity thereby forcing air into the substrate cavity. Movement of the movable magnet may generate a vacuum in the pumping cavity thereby drawing air from the ambient environment into the pumping cavity.

[0038] The movable magnet may be configured movable parallel to the longitudinal central axis of the substrate cavity. The longitudinal central axis of the substrate cavity is also referred to as the longitudinal axis of the substrate cavity. The movable magnet may be configured movable in a first direction parallel to a longitudinal axis of the substrate cavity. The movable magnet may be configured movable in a second direction parallel to a longitudinal axis of the substrate cavity. The movable magnet may be configured movable in a second direction parallel to a longitudinal axis of the substrate cavity and opposite to the first direction. The first direction may be a proximal axial direction. The second direction may be a distal axial direction.

[0039] The movable magnet may be configured movable along the longitudinal central axis of the pumping cavity. The longitudinal central axis of the pumping cavity is also referred to as the longitudinal axis of the pumping cavity. The longitudinal axis of the pumping cavity may be parallel or along to the longitudinal axis of the substrate cavity. The longitudinal axis of the pumping cavity may align with the longitudinal axis of the substrate cavity. The movable magnet may be configured movable in a first direction along the longitudinal axis of the pumping cavity. The movable magnet may be configured movable in a second direction along the longitudinal axis of the pumping cavity. The movable magnet may be configured movable in a second direction along the longitudinal axis of the pumping cavity and opposite to the first direction. The first direction may be a proximal axial direction. The second direction may be a distal axial direction.

[0040] The movable magnet may be configured movable in the first direction along a longitudinal axis of the pumping cavity, wherein movement of the movable magnet in a first direction may pressurize the pumping cavity. The movement of the movable magnet in the first direction may force air into the substrate cavity. The movement of the movable magnet in the second direction may expand the pumping cavity. The expansion of the pumping cavity may draw air from the ambient environment into the pumping cavity.

[0041] The first chamber may be fluidly connected to the substrate cavity through the first one-way valve. The first chamber may be fluidly connected to the second chamber through the second one-way valve. The second chamber may be fluidly connected to the ambient environment through a pump air inlet.

[0042] Alternatively, airflow may extend from the ambient environment through the first chamber into the substrate cavity. The airflow may not extend through the second chamber. The first chamber may be fluidly connected with the ambient environment via a second oneway valve, preferably arranged in a pump air inlet. The first chamber may be fluidly connected with the with the substrate cavity via a first one-way valve. The second one-way valve may allow an airflow from the ambient environment into the first chamber. The second one-way valve may prevent backflow of air from the first chamber to the ambient environment. The first one-way valve may allow airflow from the first chamber into the substrate cavity. The first one-way valve may prevent backflow of air from the substrate cavity into the first chamber. The second chamber may comprise a first aperture and a second aperture for pressure equalization.

[0043] The movable magnet may comprise a first guiding element. The movable magnet may comprise a second guiding element. The first guiding element may be arranged radially inwards of a permanent magnet. The second guiding element may be arranged radially outwards of the permanent magnet. The permanent magnet may be received in-between the first guiding element and the second guiding element.

[0044] The first guiding element may be tubular. The second guiding element may be tubular. The second guiding element may have a larger diameter than the first guiding element. This may allow the permanent magnet to be received in-between the first guiding element and the second guiding element. The permanent magnet may be tubular.

[0045] The first guiding element may be magnetic. The first guiding element may not be magnetic. The first guiding element may be ferromagnetic. The second guiding element may be magnetic. The second guiding element may not be magnetic. The second guiding element may be ferromagnetic. The first guiding element and the second guiding element may not be magnetic. The first guiding element and the second guiding element may be ferromagnetic. The first guiding element and the second guiding element may be magnetic.

[0046] The first guiding element may comprise a first surface. The first surface of the first guiding element may face the first end of the pumping cavity. The first guiding element may comprise a second surface. The second surface of the first guiding element may face the second end of the pumping cavity.

[0047] The first guiding element may comprise a groove. The groove may extend from the second surface of the first guiding element to the first surface of the guiding element, preferably parallel to the longitudinal axis of the pumping cavity. The groove may be shaped cylindric. The groove may be tubular. The groove may be of any suitable shape. The first guiding element may comprise at least one groove. The first guiding element may comprise more than one groove. The first guiding element may comprise several grooves.

[0048] The groove may receive a protrusion. The protrusion may be attached to the second end of the pumping cavity. The protrusion may be attached to the second end of the pumping cavity facing the second surface of the first guiding element, preferably facing the groove. The second end of the pumping cavity may comprise more than one protrusion. The protrusion may act as an axial guide for the movable magnet.

[0049] The movable magnet may be tubular. The movable magnet may be tubular and may be received within a tubular pumping cavity. The movable magnet may be of any shape suitable for the pumping cavity.

[0050] The pump may comprise an elastic sealing element. The elastic sealing element may be elastic. The elastic sealing element may be flexible. The elastic sealing element may be impermeable to air. The elastic sealing element may be impermeable to liquids. The elastic sealing element may be a membrane.

[0051] The elastic sealing element may sealingly encompass the pumping cavity. The elastic sealing element may sealingly encompass the pumping cavity and the first one-way valve. The elastic sealing element may sealingly encompass the pumping cavity, the first one-way valve and the second one-way valve. The elastic sealing element may be a membrane, which may sealingly encompass the pumping cavity, the first one-way valve and the second one-way valve.

[0052] The elastic sealing element may be attached to the first end of the pumping cavity. The elastic sealing element may be attached to the first surface of the first guiding element. The elastic sealing element may be attached to the first end of the pumping cavity. The elastic sealing element may be attached to the first end of the pumping cavity and to the first surface of the first guiding element. The elastic sealing element may sealingly encompass the pumping cavity, the first one-way valve and the second one-way valve.

[0053] The elastic sealing element may fluidly separate the pumping cavity from the interior of the aerosol-generating device apart from the substrate cavity. The membrane may be circular. The membrane may be annular. The membrane may be of any shape suitable to separate the pumping cavity from the interior of the aerosol-generating device apart from the substrate cavity. Separating the pumping cavity from the interior of the aerosol-generating device apart from the substrate cavity may lead to a more effective airflow during the actuation of the pump, thereby improving energy efficiency.

[0054] The aerosol-generating device may further comprise a first biasing element. The first biasing element may be flexible. The first biasing element may be attached to the first end of the pumping cavity. The first biasing element may be attached to the first surface of the first guiding element. The first biasing element may be attached to the first end of the pumping cavity and to the first surface of the first guiding element. The first biasing element may bias the movable magnet. The first biasing element may bias the movable magnet, preferably towards the second end of the pumping cavity.

[0055] The first biasing element may be configured to bias the movable magnet against a movement direction induced by the induction coil. The induction coil may move the movable magnet from a first position along the longitudinal axis of the pumping cavity to a second position. The first biasing element applies a biasing force to the movable magnet, which biases the movable magnet towards the first position. If the biasing force exceeds the magnetic force induced by the induction coil, the movable magnet may be moved into its first position. During operation, the induction coil may move the movable magnet from the first position to the second position. When the movable magnet reaches the second position, the polarity of the alternating current supplied to the induction coil may switch such that the induction coil no longer pushes the movable magnet towards the second position. Subsequently, the first biasing element pushes the movable magnet back to the first position.

[0056] The aerosol-generating device may further comprise a second biasing element. The second biasing element may be attached to the second end of the pumping cavity. The second biasing element may be attached to the second surface of the first guiding element The second biasing element may bias the movable magnet towards the first end of the pumping cavity. The second biasing element may be flexible. The second biasing element may bias the movable magnet towards the second position. The average biasing force exerted by the second biasing element may be smaller than the average biasing force exerted by the first biasing element. In other words, the second biasing element may be weaker than the first biasing element. The additional use of a second biasing element may improve control over the actuation of the pump.

[0057] The second biasing element may be configured to bias the movable magnet against a biasing direction of the first biasing element. The biasing force of the second biasing element may be directed into the same direction as the induction force applied by the induction coil, thereby supporting the induction coil to move the movable magnet. Electric energy required to move the movable magnet may be reduced and thereby the energy consumption of the aerosol-generating device may be minimized.

[0058] The induction coil may be configured to move the movable magnet with a frequency corresponding to a resonance frequency of one or both of the first biasing element and the second biasing element. This resonant frequency may be the frequency of the alternating current supplied to the induction coil. Moving the movable magnet with a frequency corresponding to the resonance frequency of one or both of the first biasing element and the second biasing element may increase control over the actuation of the pump and thereby improve energy efficiency.

[0059] One or both of the first biasing element and the second biasing element may be configured as a spring. The first biasing element may be configured as a spring. The second biasing element may be configured as a spring. The first biasing element and the second biasing element may be each configured as a spring. The first biasing element may be configured as a first spring. The second biasing element may be configured as a second spring. The first spring may comprise a higher spring stiffness than the second spring. The second spring may comprise a higher spring stiffness than the first spring. The first spring may comprise the same spring stiffness as the second spring.

[0060] The first biasing element may be arranged proximal of the movable magnet and the second biasing element may be arranged distal of the movable magnet.

[0061] The first biasing element may be encompassed by the sealing element. The second biasing element may be encompassed by the sealing element. The first biasing element and the second element may be encompassed by the sealing element. The first biasing element may be not encompassed by the sealing element. The second biasing element may be not encompassed by the sealing element. Neither the first biasing element nor the second biasing element may be encompassed by the sealing element. Advantages of such a design, where the elastic sealing element may not encompass the biasing elements, may be an increased volume of the pumping cavity, an improved motion of the airflow inside the pumping cavity and that the spring would not be in contact with the aerosol.

[0062] The induction coil may be configured as a single direction coil or as a dual direction coil. A single direction coil may also be referred to as single coil. A single coil may comprise a first part and a second part, wherein the first part is wound into a first direction and the second part is wound into a second direction, opposite of the first direction. A single coil with the first part and the second part wound in opposite directions may also be referred to as dual coil. A first coil and a second coil arranged in parallel, wherein the first coil is wound into a first direction and wherein the second coil is wound into a second direction opposite to the first direction, may also be referred to as dual coil.

[0063] The induction coil may be configured as a dual coil, wherein both coils of the dual coil may be operated by the same power source. Alternatively, each coil of the dual coil may be operated by an individual power source. Both coils of the dual coil may be arranged in parallel. The coils of the dual coil may be concentrically arranged. Both coils of the dual coil may be arranged in series.

[0064] The induction coil may be operated with an AC current, preferably an AC current with a Square wave, Triangle wave, Sine wave or sawtooth pattern. The induction coil may be operated with an AC current via the microprocessor, preferably via a H-bridge controlled by the microprocessor.

[0065] The induction coil may be configured as a single coil, wherein the single coil may be operated with an AC current.

[0066] Alternatively, the induction coil may be operated by a DC current, preferably a pulsed DC current. The induction coil may be configured as a dual coil, wherein both coils of the dual coil may be operated by the same power source, wherein the power source provides a DC, and wherein both coils of the dual coil may be arranged in parallel. The induction coil may be configured as a dual coil, wherein both coils of the dual coil may be operated by the same power source, wherein the power source provides a DC, and wherein both coils of the dual coil may be arranged in series. Each coil of the dual coil may comprise an individual DC power source, wherein the individual power sources may be alternately activated. The individual DC power sources may be alternately activated by the controller of the aerosolgenerating device.

[0067] As used herein, the terms ‘proximal’, ‘distal’, ‘downstream’ and ‘upstream’ are used to describe the relative positions of components, or portions of components, of the aerosol- generating device in relation to the direction in which a user draws on the aerosol-generating device during use thereof.

[0068] The aerosol-generating device may comprise a mouth end through which in use an aerosol exits the aerosol-generating device and is delivered to a user. The mouth end may also be referred to as the proximal end. In use, a user draws on the proximal or mouth end of the aerosol-generating device in order to inhale an aerosol generated by the aerosolgenerating device. Alternatively, a user may directly draw on an aerosol-generating article inserted into an opening at the proximal end of the aerosol-generating device. The opening at the proximal end may be an opening of the substrate cavity. The substrate cavity may be configured to receive the aerosol-generating article. The aerosol-generating device comprises a distal end opposed to the proximal or mouth end. The proximal or mouth end of the aerosol-generating device may also be referred to as the downstream end and the distal end of the aerosol-generating device may also be referred to as the upstream end. Components, or portions of components, of the aerosol-generating device may be described as being upstream or downstream of one another based on their relative positions between the proximal, downstream or mouth end and the distal or upstream end of the aerosolgenerating device.

[0069] As used herein, an ‘aerosol-generating device’ relates to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, for example part of a smoking article. An aerosolgenerating device may be a smoking device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is directly inhalable into a user’s lungs thorough the user's mouth. An aerosol-generating device may be a holder. The device may be an electrically heated smoking device. The aerosol-generating device may comprise a housing, electric circuitry, a power supply, a heating chamber and a heating element.

[0070] As used herein with reference to the present invention, the term ‘smoking’ with reference to a device, article, system, substrate, or otherwise does not refer to conventional smoking in which an aerosol-forming substrate is fully or at least partially combusted. The aerosol-generating device of the present invention is arranged to heat the aerosol-forming substrate to a temperature below a combustion temperature of the aerosol-forming substrate, but at or above a temperature at which one or more volatile compounds of the aerosolforming substrate are released to form an inhalable aerosol.

[0071] The aerosol-generating device may comprise electric circuitry. The electric circuitry may comprise a microprocessor, which may be a programmable microprocessor. The microprocessor may be part of a controller. The electric circuitry may comprise further electronic components. The electric circuitry may be configured to regulate a supply of power to the heating element. Power may be supplied to the heating element continuously following activation of the aerosol-generating device or may be supplied intermittently, such as on a puff-by-puff basis. The power may be supplied to the heating element in the form of pulses of electrical current. The electric circuitry may be configured to monitor the electrical resistance of the heating element, and preferably to control the supply of power to the heating element dependent on the electrical resistance of the heating element.

[0072] The aerosol-generating device may comprise a power supply, typically a battery, within a main body of the aerosol-generating device. In one embodiment, the power supply is a Lithium-ion battery. Alternatively, the power supply may be a Nickel-metal hydride battery, a Nickel cadmium battery, or a Lithium based battery, for example a Lithium-Cobalt, a Lithium-lron-Phosphate, Lithium Titanate or a Lithium-Polymer battery. As an alternative, the power supply may be another form of charge storage device such as a capacitor. The power supply may require recharging and may have a capacity that enables to store enough energy for one or more usage experiences; for example, the power supply may have sufficient capacity to continuously generate aerosol for a period of around six minutes or for a period of a multiple of six minutes. In another example, the power supply may have sufficient capacity to provide a predetermined number of puffs or discrete activations of the heating element.

[0073] In any of the aspects of the disclosure, the heating element may comprise an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum platinum, gold and silver. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium- titanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-, gold- and iron- containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai® and iron-manganese-aluminium based alloys. In composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required.

[0074] As described, in any of the aspects of the disclosure, the heating element may be part of an aerosol-generating device. The aerosol-generating device may comprise an internal heating element or an external heating element, or both internal and external heating elements, where "internal" and "external" refer to the aerosol-forming substrate. An internal heating element may take any suitable form. For example, an internal heating element may take the form of a heating blade. Alternatively, the internal heater may take the form of a casing or substrate having different electro-conductive portions, or an electrically resistive metallic tube. Alternatively, the internal heating element may be one or more heating needles or rods that run through the center of the aerosolforming substrate. Other alternatives include a heating wire or filament, for example a Ni-Cr (Nickel-Chromium), platinum, tungsten or alloy wire or a heating plate. Optionally, the internal heating element may be deposited in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track on a suitable insulating material, such as ceramic material, and then sandwiched in another insulating material, such as a glass. Heaters formed in this manner may be used to both heat and monitor the temperature of the heating elements during operation.

[0075] An external heating element may take any suitable form. For example, an external heating element may take the form of one or more flexible heating foils on a dielectric substrate, such as polyimide. The flexible heating foils can be shaped to conform to the perimeter of the substrate cavity. Alternatively, an external heating element may take the form of a metallic grid or grids, a flexible printed circuit board, a molded interconnect device (MID), ceramic heater, flexible carbon fibre heater or may be formed using a coating technique, such as plasma vapour deposition, on a suitable shaped substrate. An external heating element may also be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between two layers of suitable insulating materials. An external heating element formed in this manner may be used to both heat and monitor the temperature of the external heating element during operation.

[0076] As an alternative to an electrically resistive heating element, the heating element may be configured as an induction heating element. The induction heating element may comprise an induction coil and a susceptor. In general, a susceptor is a material that is capable of generating heat, when penetrated by an alternating magnetic field. When located in an alternating magnetic field. If the susceptor is conductive, then typically eddy currents are induced by the alternating magnetic field. If the susceptor is magnetic, then typically another effect that contributes to the heating is commonly referred to hysteresis losses. Hysteresis losses occur mainly due to the movement of the magnetic domain blocks within the susceptor, because the magnetic orientation of these will align with the magnetic induction field, which alternates. Another effect contributing to the hysteresis loss is when the magnetic domains will grow or shrink within the susceptor. Commonly all these changes in the susceptor that happen on a nano-scale or below are referred to as “hysteresis losses”, because they produce heat in the susceptor. Hence, if the susceptor is both magnetic and electrically conductive, both hysteresis losses and the generation of eddy currents will contribute to the heating of the susceptor. If the susceptor is magnetic, but not conductive, then hysteresis losses will be the only means by which the susceptor will heat, when penetrated by an alternating magnetic field. According to the invention, the susceptor may be electrically conductive or magnetic or both electrically conductive and magnetic. An alternating magnetic field generated by one or several induction coils heat the susceptor, which then transfers the heat to the aerosol-forming substrate, such that an aerosol is formed. The heat transfer may be mainly by conduction of heat. Such a transfer of heat is best, if the susceptor is in close thermal contact with the aerosol-forming substrate.

[0077] As used herein, the term ‘aerosol-generating article’ refers to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. For example, an aerosol-generating article may be a smoking article that generates an aerosol that is directly inhalable into a user’s lungs through the user's mouth. An aerosolgenerating article may be disposable.

[0078] As used herein, the term ‘aerosol-forming substrate’ relates to a substrate capable of releasing one or more volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. An aerosol-forming substrate may conveniently be part of an aerosol-generating article or smoking article.

[0079] The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosolforming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating. The aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may comprise an aerosol former that facilitates the formation of a dense and stable aerosol. Examples of suitable aerosol formers are glycerine and propylene glycol.

[0080] The aerosol-generating substrate preferably comprises homogenised tobacco material, an aerosol-former and water. Providing homogenised tobacco material may improve aerosol generation, the nicotine content and the flavour profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process of making homogenised tobacco involves grinding tobacco leaf, which more effectively enables the release of nicotine and flavours upon heating.

[0081] The invention further relates to a method for removing excess moisture in an aerosolgenerating device as described herein, wherein the method comprises actuating the pump before a user experience of the aerosol-generating device. 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.

[0082] Example 1. An aerosol-generating device comprising: a substrate cavity for receiving an aerosol-forming substrate, an induction actuated airflow pump, wherein the pump is fluidly connected with the substrate cavity, and wherein the pump is configured to pump air into the substrate cavity.

[0083] Example 2. The aerosol-generating device according to example 1, wherein the pump comprises a movable magnet.

[0084] Example 3. The aerosol-generating device according to example 2, wherein the pump comprises an induction coil arranged at least partly surrounding the magnet.

[0085] Example 4. The aerosol-generating device according to example 3, wherein the induction coil is configured to inductively move the movable magnet upon power supply to the induction coil.

[0086] Example 5. The aerosol-generating device according to any of the preceding examples, wherein the pump comprises a pumping cavity.

[0087] Example 6. The aerosol-generating device according to example 5, wherein the pumping cavity is fluidly connected with the substrate cavity via a first one-way valve.

[0088] Example 7. The aerosol-generating device according to example 6, wherein the first one-way valve allows airflow from the pumping cavity to the substrate cavity.

[0089] Example 8. The aerosol-generating device according to any of examples 5 to 7, wherein the pumping cavity is fluidly connected with the ambient environment via a second one-way valve.

[0090] Example 9. The aerosol-generating device according to example 8, wherein the second one-way valve allows airflow from the ambient environment to the pumping cavity.

[0091] Example 10. The aerosol-generating device according to example 4 and any of examples 5 to 9, wherein movement of the movable magnet pressurizes the pumping cavity thereby forcing air into the substrate cavity.

[0092] Example 11. The aerosol-generating device according to any of the preceding examples, wherein the movable magnet of example 2 is configured movable parallel to a longitudinal axis of the substrate cavity.

[0093] Example 12. The aerosol-generating device according to example 11, wherein the movable magnet further comprises a first guiding element and a second guiding element, wherein the first guiding element is arranged radially inwards of a permanent magnet and the second guiding element is arranged radially outwards of the permanent magnet. Example 13. The aerosol-generating device according to any of the preceding examples, wherein the movable magnet of example 2 is tubular.

[0094] Example 14. The aerosol-generating device according to any of the preceding examples, wherein the pump comprises an elastic sealing element.

[0095] Example 15. The aerosol-generating device according to example 14, wherein the elastic sealing element sealingly encompasses the pumping cavity of example 5.

[0096] Example 16. The aerosol-generating device according to example 15, wherein the elastic sealing element fluidly separates the pumping cavity from the interior of the aerosolgenerating device apart from the substrate cavity.

[0097] Example 17. The aerosol-generating device according to any of the preceding examples, wherein the aerosol-generating device further comprises a first biasing element.

[0098] Example 18. The aerosol-generating device according to example 17, wherein the first biasing element is configured to bias the movable magnet of example 2 against a movement direction induced by the induction coil of example 4.

[0099] Example 19. The aerosol-generating device according to any of the preceding examples, wherein the aerosol-generating device further comprises a second biasing element.

[0100] Example 20. The aerosol-generating device according to example 19, wherein the second biasing element is configured to bias the movable magnet of example 2 against a biasing direction of the first biasing element of example 17.

[0101] Example 21. The aerosol-generating device according to any of the preceding examples, wherein the induction coil of example 3 is configured to move the movable magnet with a frequency corresponding to a resonance frequency of one or both of the first biasing element of example 17 and the second biasing element of example 19.

[0102] Example 22. The aerosol-generating device according to any of the preceding examples, wherein one or both of the first biasing element of example 17 and the second biasing element of example 19 is configured as a spring.

[0103] Example 23. The aerosol-generating device according to any of the preceding examples, wherein the first biasing element of example 17 is arranged proximal of the movable magnet of example 2 and the second biasing element of example 19 is arranged distal of the movable magnet.

[0104] Example 24. The aerosol-generating device according to any of the preceding examples, wherein the induction coil of example 3 is configured as a single direction coil or as a dual direction coil.

[0105] Example 25. A method of removing excess moisture in an aerosol-generating device according to any of the preceding examples, wherein the method comprises actuating the pump before a user experience of the aerosol-generating device. Example 26. Use of an induction actuated airflow pump according to any of the preceding examples for an aerosol-generating device, wherein the aerosol-generating device is configured to vaporize an aerosol-generating substrate to generate an aerosol, and wherein the generated aerosol is released from the aerosol-generating device via the induction actuated airflow pump, preferably when the induction actuated airflow pump is activated.

[0106] Example 27. Use of an induction actuated airflow pump according example 26, wherein the generated aerosol comprises one or more of a scent, flavor or medicament.

[0107] Example 28. Use of an induction actuated airflow pump according to example 27, wherein the aerosol-generating device is portable.

[0108] Example 29. Use of an induction actuated airflow pump according to example 28, wherein the aerosol-generating device is a hand-held device.

[0109] Example 30. Use of the induction actuated airflow pump according to example 29, wherein the aerosol is a medicament, which is inhalable by a user, preferably without puffing.

[0110] Example 31. Use of the induction actuated airflow pump according to example 27, wherein the aerosol-generating device can be mounted onto a surface.

[0111] Example 32. Use of the induction actuated airflow pump according to example 31 , wherein the surface is part of a building’s interior, preferably one of a wall, ceiling or floor.

[0112] Example 33. Use of the induction actuated airflow pump according to example 31 , wherein the surface is part of a vehicle’s interior, preferably the interior of a car.

[0113] Example 34. Use of an induction actuated airflow pump according to any of the preceding examples, wherein the aerosol is released as a scent, preferably as an air refreshener.

[0114] Example 35. Use of an induction actuated airflow pump according to any of the preceding examples, wherein the induction actuated airflow pump is activated by the user, preferably with one of a button, interface, or switch.

[0115] Example 36. Use of an induction actuated airflow pump according to examples 31 to 35, wherein the aerosol-generating device is part of the car interior and is activated by the user, preferably via car controls.

[0116] Example 37. Use of the induction actuated airflow pump according to example 31 , wherein the aerosol is released as a scent, preferably the scent being repellant to insects.

[0117] Features described in relation to one embodiment may equally be applied to other embodiments of the invention.

[0118] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0119] Fig. 1 shows a sectional side view of an embodiment of an aerosol-generating device; Fig. 2 shows a top view of the aerosol-generating device of Fig. 1 ;

[0120] Fig. 3 shows an embodiment of an induction actuated air flow pump;

[0121] Fig. 4 shows an embodiment of the induction actuated air flow pump;

[0122] Fig. 5 shows an embodiment of the induction actuated air flow pump;

[0123] Figure 1 shows an aerosol-generating device 10. The aerosol-generating device 10 comprises a substrate cavity 12 for receiving an aerosol-generating article comprising an aerosol-forming substrate. The substrate cavity 12 is arranged at a proximal end 14 of the aerosol-generating device 10. At a distal end 16 of the aerosol-generating device 10, a main air inlet 18 is arranged. The main air inlet 18 enables ambient air to be drawn into substrate cavity 12. When a user draws on the proximal end 14 of the aerosol-generating article, the air will be drawn from the ambient environment into the substrate cavity 12 and subsequently through the aerosol-generating article received in the substrate cavity 12 to be inhaled by the user.

[0124] Further, Figure 1 shows a printed circuit board 20 and an induction actuated airflow pump 22. The pump 22 is formed by a pump housing 24, which is arranged around a sidewall 26 of the substrate cavity 12. The volume inside the pump housing 24 defines a pumping cavity 28. A membrane 30 is arranged dividing the pumping cavity 28 into a first chamber 32 and a second chamber 34.

[0125] The first chamber 32 is fluidly connected with the substrate cavity 12 via a first oneway valve 36. The first one-way valve 36 enables airflow in the direction of the substrate cavity 12 and prevents airflow from the substrate cavity 12 into the first chamber 32. The first one-way valve 36 is arranged in the sidewall 26 of the substrate cavity 12. The first chamber 32 is further fluidly connected to the second chamber 34 via a second one-way valve 38. The second one-way valve 38 enables airflow from the second chamber 34 into the first chamber 32 and prevents backflow from the first chamber 32 into the second chamber 34.

[0126] The second chamber 34 is fluidly connected to the ambient environment through a tube 40 with a pump air inlet 42. The pump air inlet 42 is arranged at the distal end 16 of the aerosol-generating device 10.

[0127] The pumping cavity 28 is tubular and a tubular movable magnet 44 is arranged within the pumping cavity 28. The movable magnet 44 comprises a permanent magnet 46 and a magnetic structure 48, which encloses the permanent magnet 46. The movable magnet 44 is movable parallel to a longitudinal axis Lsof the substrate cavity 12.

[0128] The movable magnet 44 is biased towards the distal end 16 of the aerosol-generating device 10 by a first biasing element in the form of a spring disc 50. An induction coil in form of a single coil 52 is wound around the sidewall 26 of the substrate cavity 12. The single coil 52 is arranged between the sidewall 26 of the substrate cavity 12 and the movable magnet 44.

[0129] Upon power supply of an AC current from a power supply (not shown) of the aerosolgenerating device 10, the AC current is fed to the single coil 52, which generates a magnetic field. The magnetic field of the single coil 52 interacts with the permanent magnetic field of the permanent magnet 46 resulting in a magnetic force. The magnetic force is applied to the movable magnet 44, leading to the displacement of the movable magnet 44 towards the proximal end 14 of the aerosol-generating device 10 along the longitudinal axis Ls of the substrate cavity 12. Simultaneously, the spring disc 50 applies an elastic force to the movable magnet 44 opposing to the magnetic force.

[0130] The movement of the movable magnet 44 stops, once the elastic force exceeds the magnetic force or when the polarity of the AC current switches. In this case, the movable magnet 44 is displaced towards the distal end 16 of the aerosol-generating device 10 by means of the spring disc 50.

[0131] Upon a constant power supply the displacement direction of the movable magnet 44 alternates constantly resulting in a reciprocating movement of the movable magnet 44.

[0132] Displacement of the movable magnet 44 towards the proximal end 14 of the aerosolgenerating device 10 leads to an expansion of the second chamber 34. As a result, a vacuum is generated inside the second chamber 34, which draws air from the ambient environment through the pump air inlet 42 and the tube 40 into the second chamber 34.

[0133] The subsequent movement of the movable magnet 44 towards the distal end 16 of the aerosol-generating device 10 forces the air from the second chamber 34 through the second one-way valve 38 into the first chamber 32.

[0134] Due to the reciprocating movement, the movable magnet 44 moves again towards the proximal end 14 of the aerosol-generating device 10 and thereby the air from the first chamber 32 is forced through the first one-way valve 36 into the substrate cavity 12.

[0135] Figure 2 shows a cross-section of the embodiment of Figure 1 from a top view. This view shows a part of the first chamber 32, which is separated from the second chamber 34 via the membrane 30. The single coil 52 is wound around the substrate cavity 12. The permanent magnet 46 enclosed in the magnetic structure 48 surrounds the single coil 52, while being radially distanced from the single coil 52. Due to the reciprocating movement of the movable magnet 44, airflow is forced into the first chamber 32 from the second chamber 34 (not depicted in Figure 2).

[0136] Figure 3 shows an embodiment of the induction actuated airflow pump 22. The pump 22 is fluidly connected to the substrate cavity 12 via a connection element 54. The pumping cavity 28 comprises a first end 56 and a second end 58. The first end 56 of the pumping cavity 28 is adjacent to the connection element 54. The second end 58 of the pumping cavity 28 is arranged in an opposite direction, distal to the connection element 54.

[0137] The pumping cavity 28 is tubular and arranged surrounding the sidewall 26 of the substrate cavity 12. The tubular pumping cavity 28 receives the tubular movable magnet 44. The movable magnet 44 comprises a permanent magnet 46 sandwiched between a first guiding element 60 and a second guiding element 62. The movable magnet 44 is movable parallel to a longitudinal axis LP of the pumping cavity 28.

[0138] The first guiding element 60 is arranged surrounding the sidewall 26 of the substrate cavity 12. The first guiding element 60 comprises a first surface 64 facing the first end 56 of the pumping cavity 28 and a second surface 66 facing the second end 58 of the pumping cavity 28. The second guiding element 62 is in contact with the pump housing 24. Additionally, the permanent magnet 46 is enclosed within a magnetic structure 48.

[0139] In contrast to the embodiment of Figure 1, the movable magnet 44 in Figure 3 is surrounded by the induction coil 68. In particular, the induction coil 68 is configured as a dual coil 68, which is wound around the pump housing 24.

[0140] The pump 22 comprises a first aperture 70 for pressure equalization and a second aperture 72 for pressure equalization, which are arranged in the second end 58 of the pumping cavity 28.

[0141] The pump 22 comprises a first one-way valve 36 and a second one-way valve 38 at the first end 56 of the pumping cavity 28. The first one-way valve 36 allows an airflow from the pumping cavity 28 through the connection element 54 into the substrate cavity 12. Additionally, the substrate cavity 12 comprises a main air inlet 18, through which air is forced drawn the ambient environment into the substrate cavity 12 during a puff. The second oneway valve 38 is arranged in a pump air inlet 42 and allows an airflow from the ambient environment into the pumping cavity 28.

[0142] During use, power is supplied to the dual coil 68, which generates a magnetic field surrounding the dual coil 68. The magnetic field of the permanent magnet 46 interacts with the generated magnetic field of the dual coil 68, which results in a magnetic force. The magnetic force displaces the movable magnet 44 towards the first end 56 of the pumping cavity 28 pressurizing the pumping cavity 28. Subsequently, the airflow is forced through the first one-way valve 36 and the connection element 54 into the substrate cavity 12.

[0143] Switching the polarity of the current results in an inversion of the dual coil 68’s magnetic field. The interaction of the dual coil 68’s inversed magnetic field with the static magnetic field of the permanent magnet 46 redirects the magnetic force in an opposite direction, thereby displacing the movable magnet 44 towards the second end 58 of the pumping cavity 28. Movement of the movable magnet 44 towards the second end 58 of the pumping cavity 28 generates a vacuum within the pumping cavity 28. Due to the vacuum, air is forced from the ambient environment through the second one-way valve 38 into the pumping cavity 28. Periodically switching of the current polarity results in a reciprocating movement of the movable magnet 44.

[0144] Figure 4 shows a variation of the embodiment of Figure 3. In this example, the pump 22 comprises an elastic sealing element in the form of a membrane 30. The membrane 30 is attached to the first surface 64 of the first guiding element 60 and to the first end 56 of the pumping cavity 28. The membrane 30 sealingly encompasses the pumping cavity 28, the first one-way valve 36, the second one-way valve 38 and a first surface 64 of the first guiding element 60. Additionally, the induction coil of the embodiment in Figure 4 is a single coil 52 wound over a half of the pump 22 housing and arranged proximal to the first end 56 of the pumping cavity 28. Similar to the embodiment of Figure 1, the movable magnet 44 in Figure 4 is displaced due to power supply, particularly an AC current, to the single coil 52. The airflow extends through the pumping cavity 28 within the membrane 30. Displacement of the movable magnet 44 towards the first end 56 of the pumping cavity 28 compresses the membrane 30. The compression of the membrane 30 forces air from the pumping cavity 28 within the membrane 30 into the substrate cavity 12 via the first one-way valve 36. Displacement of the movable magnet 44 towards the second end 58 of the pumping cavity 28 expands the membrane 30. The expansion of the membrane 30 draws air from the ambient environment into the pumping cavity 28 within the membrane 30.

[0145] Figure 5 shows an embodiment of the induction actuated airflow pump 22. The pump 22 is arranged at the distal end 16 of the substrate cavity 12. The pumping cavity 28 is fluidly connected through a connection element 54 to the distal end 16 of the substrate cavity 12. The pumping cavity 28 comprises a first end 56 and a second end 58. The first end 56 of the pumping cavity 28 is arranged adjacent to the connection element 54 and the second end 58 of the pumping cavity 28 is arranged distal to the connection element 54.

[0146] The pump 22 comprises a pump housing 24. An induction coil is wound as a single coil 52 around the pumping housing 26, particularly proximal to the first end 56 of the pumping cavity 28. The pumping cavity 28 receives a movable magnet 44, which is movable along a longitudinal axis LP of the pumping cavity 28. In this example, the longitudinal axis of the pumping cavity 28 aligns with the longitudinal axis Ls of the substrate cavity 12, which is not depicted.

[0147] The movable magnet 44 comprises a permanent magnet 46 sandwiched between a first guiding element 60 and a second guiding element 62. The movable magnet 44 comprises the magnetic structure 48, which encloses the permanent magnet 46. The first guiding element 60 is arranged radially central within the pumping cavity 28 and comprises a first surface 64 and a second surface 66. The first surface 64 of the first guiding element 60 faces the first end 56 of the pumping cavity. The second surface 66 of the first guiding element 60 faces the second end 58 of the pumping cavity 28. A groove 80 is extends from the first surface 64 of the first guiding element 60 to the second surface 66 of the first guiding element 60. The groove 80 aligns with a longitudinal axis of the pumping cavity 28. The groove 80 is configured to receive a similarly shaped protrusion 82. The protrusion 82 is attached to the second end 58 of the pumping cavity 28. The protrusion 82 aligns with the longitudinal axis LP of the pumping cavity 28 and extends along the longitudinal axis LP of the pumping cavity 28 facing the second surface 66 of the first guiding element 60.

[0148] The second guiding element 62 is in contact with the pump housing 24.

[0149] Further, the pumping cavity 28 comprises two biasing elements in the form of a first spring 76 and a second spring 78. The first spring 76 is attached to the first end 56 of the pumping cavity 28 and to the first surface 64 of the first guiding element 60. The first spring 76 biases the movable magnet 44 towards the proximal end 14 of the pumping cavity 28. The second spring 78 is attached to the second end 58 of the pumping cavity 28 and to the second surface 66 of the first guiding element 60. The second spring 78 biases the movable magnet 44 towards the second end 58 of the pumping cavity 28. The first spring 76 and the second spring 78 each comprise a compressed and an extended state. When the first spring 76 is compressed, the second spring 78 is extended and vice versa.

[0150] Similar to the embodiment of Figure 4, the pump of Figure 5 comprises a membrane 30, which is attached to the first end 56 of the pumping cavity 28 and to the first surface 64 of the first guiding element 60. The membrane 30 encompasses a first one-way valve 36, a second one-way valve 38 and a portion of the proximal half of the pumping cavity 28.

[0151] The first one-way valve 36 is arranged radially central in the first end 56 of the pumping cavity 28. The second one-way valve 38 is also arranged in the first end 56 of the pumping cavity 28, but radially distanced to the first one-way valve 36. The first one-way valve 36 is fluidly connected to the substrate cavity 12. The main air inlet 18 is arranged orthogonally to the substrate cavity 12. The main air inlet 18 is fluidly connected to the substrate cavity 12 and the ambient environment. When the user draws at the proximal end of the aerosol-generating article (not depicted), air is drawn from the ambient environment into the substrate cavity 12 via the main air inlet 18.

[0152] Upon power supply, the single coil 52 generates a magnetic field, which interacts with the static magnetic field of the permanent magnet 46 and results in a magnetic force acting on the movable magnet 44. In combination with the elastic forces of the first spring 76 and the second spring 78, the movable magnet 44 is oscillating in a reciprocating movement. The reciprocating movement results in a pumping action. Similar to the embodiments of Figures 1 to 4 the displacement of the movable magnet 44 towards the first end 56 of the pumping cavity 28 pressurizes the pumping cavity 28 and forces thereby air through the first one-way valve 36 into the substrate cavity 12. Displacement of the movable magnet 44 towards the second end 58 of the pumping cavity 28 generates a vacuum in the pumping cavity 28, due to the expansion of the pumping cavity 28. The vacuum within the pumping cavity 28 draws air from the ambient environment through the second one-way valve 38 into the pumping cavity 28.

[0153] Further, the pump 22 comprises a first aperture for pressure equalization 70 and a second aperture for pressure equalization 72, which are arranged in the pump housing 24.

Claims

CLAIMS1. An aerosol-generating device comprising: a substrate cavity for receiving an aerosol-forming substrate, an induction actuated airflow pump, wherein the pump is fluidly connected with the substrate cavity, and wherein the pump is configured to pump air into the substrate cavity.

2. The aerosol-generating device according to claim 1, wherein the pump comprises a movable magnet.

3. The aerosol-generating device according to claim 2, wherein the pump comprises an induction coil arranged at least partly surrounding the magnet.

4. The aerosol-generating device according to claim 3, wherein the induction coil is configured to inductively move the movable magnet upon power supply to the induction coil.

5. The aerosol-generating device according to any of the preceding claims, wherein the pump comprises a pumping cavity.

6. The aerosol-generating device according to claim 5, wherein the pumping cavity is fluidly connected with the substrate cavity via a first one-way valve.

7. The aerosol-generating device according to any of claims 5 or 6, wherein the pumping cavity is fluidly connected with the ambient environment via a second one-way valve.

8. The aerosol-generating device according to claim 4 and any of claims 5 to 7, wherein movement of the movable magnet pressurizes the pumping cavity thereby forcing air into the substrate cavity.

9. The aerosol-generating device according to any of the preceding claims, wherein the pump comprises an elastic sealing element.

10. The aerosol-generating device according to any of the preceding claims, wherein the aerosol-generating device further comprises a first biasing element.

11. The aerosol-generating device according to claim 10, wherein the first biasing element is configured to bias the movable magnet of claim 2 against a movement direction induced by the induction coil of claim 4.

12. The aerosol-generating device according to any of the preceding claims, wherein the aerosol-generating device further comprises a second biasing element.

13. The aerosol-generating device according to any of the preceding claims, wherein the induction coil of claim 3 is configured to move the movable magnet with a frequency corresponding to a resonance frequency of one or both of the first biasing element of claim 10 and the second biasing element of claim 12.

14. The aerosol-generating device according to any of the preceding claims, wherein the induction coil of claim 3 is configured as a single direction coil or as a dual direction coil.

15. A method of removing excess moisture in an aerosol-generating device according to any of the preceding claims, wherein the method comprises actuating the pump before a user experience of the aerosol-generating device.

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