Shisha system having a heating unit including two electrodes

Abstract

A shisha system includes an aerosol-generating article (90) and a shisha device (50). The aerosol-generating article (90) includes an aerosol-forming substrate (92). The shisha system further includes a first electrode (15) and a second electrode (16). The shisha device (50) includes a liquid cavity (54) configured to contain a liquid, the liquid cavity (54) having a headspace outlet (60), an article cavity (14) configured to receive the aerosol-forming substrate (92), and the article cavity (14) in fluid communication with the liquid cavity (54). The shisha device further includes an oscillator circuit (10) configured for connection to the first electrode (15) and the second electrode (16). The oscillator circuit (10) is configured to supply a radio frequency (RF) alternating current voltage to the first electrode (15) and the second electrode (16), and when an aerosol-generating article (90) is received in the article cavity (14), the oscillator circuit providing the RF voltage between the first electrode (15) and the second electrode (16) generates an alternating current radio frequency (RF) electromagnetic field between the first electrode (15) and the second electrode (16) to heat the aerosol-forming substrate (92).

Description

[Technical field]

[0001] The present disclosure relates to a shisha system for generating an aerosol from an aerosol-forming substrate. In particular, the present disclosure relates to a shisha system, a shisha device, and a shisha article for use with a shisha device. [Background technology]

[0002] A conventional shisha device is sometimes referred to in the art as a water cigarette, kalyan, nargil, or water pipe. A conventional shisha device differs from other aerosol generating devices in that volatile compounds released from a heated substrate in the shisha device are drawn through a liquid disk before being inhaled by the user. A conventional shisha device may contain one outlet, or may contain two or more outlets so that more than one user can use the device at one time.

[0003] Conventional shisha devices are typically used in combination with a shisha substrate, sometimes referred to in the art as water tobacco, tobacco molasses, or simply molasses. Conventional shisha substrates are relatively high in sugar, in some cases up to about 50 percent sugar, compared to the approximately 20 percent that may be found in conventional combustible cigarettes.

[0004] Conventional shisha devices also utilize charcoal to heat and sometimes combust the shisha base to generate an aerosol for inhalation by the user. The use of charcoal to heat the shisha base may completely or partially combust the tobacco and other ingredients in the shisha base.

[0005] Different types of electrically operated shisha systems have been proposed. Electrically operated shisha systems replace the charcoal heat source of a conventional shisha device with an electrically operated heater. Nearly all proposed electrically operated shisha systems heat the aerosol-forming substrate by one or more of the following: conduction of heat from a heating element to the aerosol-forming substrate, radiation of heat from a heating element to the aerosol-forming substrate, or drawing heated air through the aerosol-forming substrate. Most commonly, heating is achieved by passing an electric current through an electrically resistive heating element, causing Joule heating of the heating element. Induction heating systems have also been proposed, where Joule heating occurs as a result of eddy currents induced in a susceptor heating element.

[0006] One problem with previously proposed electrically operated shisha devices is that they can result in uneven heating of the aerosol-forming substrate, with the portion of the aerosol-forming substrate closest to the heating element heating up faster or to a higher temperature than the portion of the aerosol-forming substrate further away from the heating element.

[0007] It would be desirable to be able to provide uniform heating of the aerosol-forming substrate in a manner that allows for greater design flexibility and allows for heating control. Summary of the Invention

[0008] In the present disclosure, a shisha system is provided. The shisha system may include an aerosol-generating article including an aerosol-forming substrate. The shisha system may include a first electrode. The shisha system may include a second electrode. The shisha system may include a shisha device. The shisha device may include a liquid cavity configured to accommodate a liquid, the liquid cavity having a head space outlet. The shisha device may include an article cavity configured to receive an aerosol-forming article, the article cavity and the liquid cavity being in fluid communication. The shisha device may include an oscillator circuit configured for connection to the first electrode and the second electrode. The oscillator circuit may be configured to provide a radio frequency (RF) alternating voltage to the first electrode and the second electrode to heat the aerosol-forming substrate when the aerosol-generating article is received in the article cavity. The RF voltage between the first electrode and the second electrode may generate an alternating radio frequency (RF) electromagnetic field between the first electrode and the second electrode.

[0009] As used herein, the term "radio frequency (RF) alternating voltage" refers to an alternating voltage that alternates at a frequency within the radio frequency (RF) range.

[0010] In particular, the present disclosure provides a shisha system comprising a shisha device and an aerosol-generating article. The aerosol-generating article comprises an aerosol-forming substrate. The shisha system further comprises a first electrode and a second electrode. The shisha device comprises a liquid cavity configured to contain a liquid, the liquid cavity having a headspace outlet. The shisha device further comprises an article cavity configured to receive an aerosol-forming article, the article cavity and the liquid cavity being in fluid communication. The shisha device further comprises an oscillator circuit configured for connection to the first electrode and the second electrode. The oscillator circuit is configured to provide a radio frequency (RF) alternating voltage to the first electrode and the second electrode to heat the aerosol-forming substrate when the aerosol-generating article is received in the article cavity.

[0011] Such a shisha device is configured to cause dielectric heating of the aerosol-forming substrate in the article cavity when an RF voltage between the first and second electrodes generates an alternating radio frequency (RF) electromagnetic field between the first and second electrodes. The dielectric heating can be uniform across the aerosol-forming substrate without the generation of hot spots. In particular, the dielectric heating reduces the possibility of combustion of the substrate in contact with the first and second electrodes compared to conventional heaters that transfer heat to the substrate via a conductor. The shisha device allows for considerable design flexibility with respect to the shape, volume and composition of the aerosol-forming substrate and correspondingly the shape and volume of the article cavity.

[0012] The first and second electrodes may have any suitable size, shape, and configuration.

[0013] In some embodiments, the first electrode and the second electrode are disposed in or around the article cavity when the aerosol-generating article is received in the article cavity.

[0014] In some embodiments, the first electrode and the second electrode are positioned to contact the aerosol-generating article when the aerosol-generating article is received within the article cavity. Contact between the aerosol-generating article and the first and second electrodes may improve the efficiency of dielectric heating of the aerosol-forming substrate.

[0015] In some embodiments, the aerosol-generating article may comprise a wrapper or housing about the aerosol-forming substrate, and the first and second electrodes may contact the wrapper or housing of the aerosol-generating article when the aerosol-generating article is received within the article cavity. Providing a wrapper or housing about the aerosol-forming substrate may result in the elimination of the need to clean the first and second electrodes, compared to conventional heating element arrangements where aerosol-forming substrate residue may build up on the heating element.

[0016] In some embodiments, at least one of the first electrode and the second electrode is arranged to contact an aerosol-forming substrate of the aerosol-generating article when the aerosol-generating article is received within the article cavity, hi some preferred embodiments, both the first electrode and the second electrode are configured to contact the aerosol-forming substrate when the aerosol-generating article is received within the article cavity.

[0017] In some preferred embodiments, the second electrode is spaced apart from the first electrode such that at least a portion of the aerosol-forming substrate is received between the first and second electrodes. In particular, the second electrode is spaced apart from the first electrode such that at least a portion of the aerosol-forming substrate is received between the first and second electrodes when the aerosol-generating article is received within the article cavity. In these embodiments, the first electrode, the second electrode, and the aerosol-forming substrate may be considered to form a capacitor.

[0018] In some embodiments, at least one of the first and second electrodes may be substantially planar. A substantially planar electrode may have a substantially oval, circular, square, rectangular, or any other polygonal shape.

[0019] In some preferred embodiments, the first electrode is a substantially planar electrode and the second electrode is a substantially planar electrode. In these embodiments, the second electrode can be disposed substantially parallel to the first electrode. In some particularly preferred embodiments, the second electrode is disposed opposite the first electrode. The first electrode and the second electrode can be disposed on opposite sides of the article cavity. The first electrode can be disposed directly opposite the second electrode. In other words, the second electrode can be disposed facing the first electrode. The second electrode can be disposed facing the opposite of the first electrode. In some embodiments, the second electrode is disposed adjacent to or next to the first electrode. When the second electrode is disposed adjacent to or next to the first electrode, the third electrode is electrically grounded when the first electrode and the second electrode are spaced apart on the opposite side of the third electrode.

[0020] In some embodiments, at least one of the first and second electrodes may be substantially tubular. In some embodiments, at least one of the first and second electrodes may be substantially cylindrical. The electrode may be a tubular electrode having a substantially cylindrical shape.

[0021] In some embodiments, at least one of the first and second electrodes may be substantially elongated in shape.

[0022] In some preferred embodiments, one of the first electrode and the second electrode is a substantially tubular electrode, and the other of the first electrode and the second electrode is disposed within the tubular electrode. In other words, the tubular electrode may substantially surround the other cylindrically shaped electrode. In some embodiments, the first electrode is a tubular electrode, and the second electrode is disposed within the tubular first electrode. In some embodiments, the second electrode is a tubular electrode, and the first electrode is disposed within the tubular second electrode. The tubular electrode comprises an inner passage. The electrode disposed within the tubular electrode may be disposed within the inner passage of the tubular electrode. In these preferred embodiments, the first electrode and the second electrode may be disposed substantially coaxially.

[0023] In some embodiments, at least one of the first electrode and the second electrode is gas permeable to allow air to flow through the electrode. In some embodiments, at least a portion of at least one of the first electrode and the second electrode may be formed from a gas permeable material. In some embodiments, one or more slots are created in at least one of the first electrode and the second electrode. The one or more slots may be of any shape, size, number, and arrangement to allow sufficient air to flow through the electrode. In some embodiments, at least one of the first electrode and the second electrode is formed from a metal mesh.

[0024] The electrodes may have any suitable surface area. A suitable electrode surface area is about 0.5 square centimeters (cm 2 ) ~ Approximately 100 square centimeters (cm 2 For example, a suitable electrode surface area may be from about 1 square centimeter to about 80 square centimeters (cm 2 In some preferred embodiments, the electrodes may be approximately 20 square centimeters (cm 2 ) or approximately 25 square centimeters (cm 2 ) surface area.

[0025] The second electrode may be spaced apart from the first electrode by any distance, for example, the second electrode may be spaced apart from the first electrode by a distance of about 0.1 mm to about 20 mm, or about 0.1 mm to about 10 mm, or about 1 mm to about 10 mm.

[0026] In some embodiments, the shisha device includes a first electrode and a second electrode. In these embodiments, the first electrode and the second electrode may be disposed in or around the article cavity of the shisha device. The second electrode may be disposed via a gap from the first electrode such that at least a portion of the aerosol-forming substrate is received between the first electrode and the second electrode. The first electrode and the second electrode may be disposed and configured to contact the aerosol-generating article when the aerosol-generating article is received in the article cavity. In some of these embodiments, the first electrode and the second electrode are disposed in a substantially fixed position such that the aerosol-generating article may be introduced into a predetermined space between the first electrode and the second electrode. In some of these embodiments, at least one of the first electrode and the second electrode is movable relative to the other electrode to allow the aerosol-generating article to be introduced into the article cavity and to be removed from the article cavity. In some of these embodiments, any one of the first electrode and the second electrode may be disposed to penetrate the aerosol-generating article when the aerosol-generating article is received in the article cavity.

[0027] In some of these embodiments, the electrode may be configured to penetrate the aerosol-forming substrate. For example, the electrode may be in the form of a pin or a blade. Preferably, the electrode configured to penetrate the aerosol-forming substrate is elongated. In particular, when one of the first electrode and the second electrode is substantially surrounded by the other of the first electrode and the second electrode, the electrode surrounded by the other electrode may be configured to penetrate the aerosol-generating article when the aerosol-generating article is received in the article cavity. The electrode configured to penetrate the aerosol-generating article may extend into the article cavity. In some of these embodiments, where one of the first electrode and the second electrode is a cylindrical tubular electrode, the cylindrical tubular electrode may define a surface of the article cavity. In some of these embodiments, where the first electrode and the second electrode are planar electrodes, the first electrode and the second electrode may form opposing faces of the article cavity.

[0028] In some embodiments, the shisha device includes one of the first electrode and the second electrode, and the aerosol-generating article includes the other of the first electrode and the second electrode. In these embodiments, the shisha device includes electrical contacts for electrically connecting the electrodes of the aerosol-generating article to the oscillator circuit when the aerosol-generating article is received in the article cavity. In these embodiments, the electrodes of the shisha device may be disposed in or around the article cavity, and the electrical contacts of the shisha device may be disposed in or around the article cavity.

[0029] In these embodiments, the electrode of the shisha device may be any suitable type of electrode. For example, the electrode may be a planar electrode or a tubular electrode. In these embodiments, the electrode may be an elongated electrode. The electrode may be arranged to contact the aerosol-generating article when the aerosol-generating article is received within the article cavity. The electrode may be arranged to contact an aerosol-forming substrate of the aerosol-generating article when the aerosol-generating article is received within the article cavity. The electrode may be configured such that the susceptor element penetrates the aerosol-forming substrate of the aerosol-generating article when the aerosol-generating article is received within the article cavity.

[0030] In these embodiments, the electrical contacts of the shisha device are arranged to electrically connect to the electrical contacts of the aerosol-generating article when the aerosol-generating article is received in the article cavity. In these embodiments, the electrodes of the shisha device are spaced apart from the electrical contacts of the shisha device. The electrical contacts of the shisha device may be of any suitable shape and size and may be arranged in any suitable position to electrically connect with the electrical contacts of the aerosol-generating article when the aerosol-generating article is received in the article cavity. For example, the electrical contacts may be arranged on the side walls of the article cavity. The electrical contacts of the shisha device may form point contacts, ring contacts, or pin contacts.

[0031] In some embodiments, the aerosol-generating article includes a first electrode and a second electrode, and the shisha device includes a first electrical contact for contacting the first electrode and a second electrical contact for contacting the second electrode when the aerosol-generating article is received in the article cavity. The first electrical contact is arranged to electrically connect to the first electrode of the aerosol-generating article when the aerosol-generating article is received in the article cavity. The second electrical contact is arranged to electrically connect to the second electrode of the aerosol-generating article when the aerosol-generating article is received in the article cavity. The first electrical contact may be arranged in any suitable position to electrically connect to the first electrical contact of the aerosol-generating article when the aerosol-generating article is received in the article cavity. The second electrical contact may be arranged in any suitable position to electrically connect to the second electrical contact of the aerosol-generating article when the aerosol-generating article is received in the article cavity. For example, the first and / or second electrical contacts may be arranged on a sidewall of the article cavity. The first and second electrical contacts of the shisha device may form a point contact, a ring contact, or a pin contact. In some embodiments, the second electrical contact is substantially identical to the first electrical contact. In some embodiments, the second electrical contact may be different from the first electrical contact.

[0032] The shisha device includes an oscillator circuit configured to supply a radio frequency (RF) alternating voltage to a first electrode and a second electrode to heat the aerosol-forming substrate when the aerosol-generating article is received in the article cavity.

[0033] The oscillator circuit may include a radio frequency (RF) signal generator. The RF signal generator may be any suitable type of RF signal generator. In some embodiments, the RF signal generator is a solid-state RF transistor. Advantageously, the solid-state RF transistor may be configured to generate and amplify the RF electromagnetic field. Using a single transistor to provide both the generation and amplification of the RF electromagnetic field allows the shisha device to be compact. The solid-state RF transistor may be, for example, an LDMOS transistor, a GaAs FET, a SiC MESFET, or a GaN HFET.

[0034] In some embodiments, the oscillator circuit may further include a frequency synthesizer disposed between the RF signal generator and the first electrode and the second electrode.

[0035] In some embodiments, the oscillator circuit may further include a phase shift network disposed between the RF signal generator and the first and second electrodes. When the oscillator circuit includes a phase shift network, the phase shift network splits the RF energy received from the RF signal generator into two separate equal components that are out of phase with each other. Typically, the phase shift network provides one of the components to the first electrode and the other component to the second electrode. The two substantially equal components of the RF energy received from the RF signal generator are preferably substantially 90 degrees or 180 degrees out of phase with each other. The two substantially equal components may be out of phase with each other by any multiple of 90 degrees or 180 degrees. It will be understood that the exact phase relationship between the two components is not important, but rather that the two components are not in phase.

[0036] In some embodiments, the phase network is configured to split the RF energy from the RF signal generator into two substantially equal components, one out of phase with the other, with each component being applied to a different one of the first and second electrodes. In some of these embodiments, the first and second electrodes may be arranged oppositely, facing each other. In some of these embodiments, the first and second electrodes are arranged side-by-side, spaced apart from a grounded third electrode and facing the third electrode. The space between the first and second electrodes and the third electrode may form an article cavity.

[0037] As used herein, radio frequency (RF) refers to a frequency between about 1 Hertz (Hz) and about 300 Megahertz (MHz). Thus, as used herein, RF frequency includes microwave frequencies. Preferably, the RF electromagnetic field has a frequency between about 1 Hertz (Hz) and about 300 Megahertz (MHz). More preferably, the RF electromagnetic field has a frequency between about 1 Megahertz (MHz) and about 300 Megahertz (MHz). In one embodiment, the RF electromagnetic field has a frequency of about 4 Megahertz (MHz).

[0038] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate is typically a part of an aerosol-generating article. For example, the aerosol-forming substrate may be a shisha aerosol-forming substrate.

[0039] Shisha aerosol-forming substrates may also be referred to in the art as water tobacco, tobacco molasses, or simply molasses. Shisha aerosol-forming substrates may have a relatively high sugar content compared to traditional combustible cigarettes, or tobacco-based consumables that are intended to be heated without burning to mimic the experience of smoking. Aerosol-forming substrates are described in more detail below.

[0040] As used herein, the term "aerosol-generating article" refers to an article that includes an aerosol-forming substrate capable of emitting a volatile compound that can form an aerosol. For example, the aerosol-generating article may be a cartridge for a shisha device. The cartridge for a shisha device includes an aerosol-forming substrate. The cartridge for a shisha device preferably includes a shisha aerosol-forming substrate. The cartridge for a shisha device is receivable by the shisha device and operable with the shisha device to generate an aerosol that can be inhaled by a user by drawing or puffing from the mouthpiece of the shisha device. The aerosol-generating article may be disposable.

[0041] As used herein, the term "shisha device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The shisha device is separate from the aerosol-forming substrate. The shisha device is configured for combination with the aerosol-forming substrate to heat the aerosol-forming substrate. The aerosol-forming substrate may be provided as part of an aerosol-generating article. The shisha device is separate from the aerosol-generating article. The shisha device is configured for combination with the aerosol-generating article to heat the aerosol-forming substrate of the aerosol-generating article. The shisha device differs from other aerosol-generating devices in that at least the volatile compounds released from the heated substrate are drawn through the liquid plate of the shisha device before being inhaled by the user. The shisha device may include two or more outlets so that more than one user can use the device at once. The shisha device may include an airflow conduit, such as a stem pipe, for directing the volatile compounds released from the aerosol-forming substrate to the liquid plate.

[0042] The term "shisha system" as used herein refers to a combination of a shisha device and an aerosol-forming substrate or an aerosol-generating article comprising an aerosol-forming substrate, in which the aerosol-forming substrate or an aerosol-generating article comprising an aerosol-forming substrate and the shisha device cooperate to generate an aerosol.

[0043] Shisha devices differ from other aerosol generating devices in that the aerosol generated by the shisha device is drawn through a liquid (typically water) before the aerosol is inhaled by the user. More specifically, when a user puffs on a shisha device, volatile compounds released from a heated aerosol-forming substrate are drawn through an airflow conduit of the shisha device into the liquid. The volatile compounds are drawn from the liquid into the headspace of the shisha device, where they form an aerosol. The aerosol in the headspace is then drawn from the headspace at a headspace outlet for inhalation by the user. The liquid (typically water) volume acts to reduce the temperature of the volatile compounds and may impart additional water content to the aerosol formed in the headspace of the shisha device. This process adds a unique characteristic to the process of using a shisha device for the user and imparts a unique characteristic to the aerosol generated by the shisha device and inhaled by the user.

[0044] In some preferred embodiments, the shisha device comprises an airflow conduit for transporting the volatile compound released from the heated aerosol-forming substrate from the article cavity to the liquid cavity. More specifically, the shisha device may include an airflow conduit configured to transport the volatile compound released from the heated aerosol-forming substrate from the article cavity to the liquid in the liquid cavity. Typically, the airflow conduit is configured to transport the aerosol from the article cavity to below the liquid fill level of the liquid cavity. The liquid fill level of the liquid cavity is the level at which the liquid cavity is intended to be filled with liquid so that the shisha device can be optimally operated. The airflow conduit may have an opening of the liquid cavity below the liquid fill level of the liquid cavity.

[0045] The shisha device comprises a head space outlet. The head space outlet is an outlet through which aerosol may be drawn from the liquid cavity. The head space outlet may be disposed above the liquid fill level of the liquid cavity. The space above the liquid fill level of the liquid cavity is called the head space. The head space of the liquid cavity is a space in which volatile compounds drawn from the article cavity through the liquid in the liquid cavity may condense to form an aerosol suitable for inhalation by a user. The head space of the liquid cavity is not intended to contain any of the liquid in the liquid cavity. Thus, the head space may be disposed above the liquid fill level of the liquid cavity, which is the level at which the liquid cavity is intended to be filled with liquid. The head space outlet may be positioned to allow aerosol to be drawn from the liquid cavity. The head space outlet may be in fluid communication with the head space.

[0046] The mouthpiece may be fluidly connected to the head space outlet. The mouthpiece may be configured for a user to inhale the aerosol generated by the shisha device. In some embodiments, the mouthpiece may be fixed to the head space outlet. In other words, the mouthpiece may be attached to the head space outlet such that the mouthpiece cannot be removed from the head space outlet without damaging one or both of the mouthpiece and the head space outlet. The mouthpiece may be removably connectable to the head space outlet. In other words, the mouthpiece may be configured to be attached to and removed from the head space outlet. In some embodiments, the mouthpiece may be compatible with a removable standby air valve. In this way, when multiple head space outlets are provided, the number of mouthpieces can be adjusted depending on the number of users in any given use session without adversely affecting the resistance to withdrawal (RTD) of the device. The mouthpiece may include a hose connected to the head space outlet. The hose may be a flexible hose.

[0047] The mouthpiece may include an activation element. The activation element may comprise a switch that is activateable by a user. The mouthpiece may comprise a puff sensor arranged to detect a user puffing on the mouthpiece. The activation element may comprise a switch that is activateable by both a user and a puff sensor. The activation element may be operably coupled to a control circuit of the shisha device. The activation element may be wirelessly coupled to the control circuit of the shisha device. Activation of the activation element may cause the control circuit of the shisha device to activate the heating element, rather than constantly supplying power to the heating element. As a result, use of an activation element may function to conserve energy compared to devices not employing such an element, providing on-demand heating rather than constant heating.

[0048] The shisha device may include multiple head space outlets. For example, the shisha device may include two, three, four, five, or six head space outlets. Providing multiple head space outlets may allow multiple users to draw aerosol from the liquid cavity at one time. In other words, providing multiple head space outlets may allow multiple users to use the shisha device simultaneously.

[0049] The shisha device comprises an article cavity configured to receive an aerosol-generating article that includes an aerosol-forming substrate.

[0050] The article cavity may include one or more walls that define the article cavity.

[0051] One of the one or more walls of the article cavity may include a first electrode. One of the one or more walls of the article cavity may include a second electrode. In some embodiments, at least a portion of one of the one or more walls may form the first electrode. In some embodiments, at least a portion of one of the one or more walls may form the second electrode. One wall of the article cavity may form the first electrode. One wall of the article cavity may form the second electrode. In some embodiments, the article cavity includes a first wall that forms the first electrode and a second wall that forms the second electrode. Opposing walls of the article cavity may form the first electrode and the second electrode.

[0052] A portion of at least one of the one or more walls may form an electrical contact for contacting an electrode of an aerosol-generating article. In some embodiments, the article cavity comprises a first wall comprising a first electrical contact for contacting a first electrode of an aerosol-generating article received within the article cavity, and the article cavity comprises a second wall comprising a second electrical contact for contacting a second electrode of an aerosol-generating article received within the article cavity. Opposing walls of the article cavity may include the first electrical contact and the second electrical contact.

[0053] Air must also be permitted to enter the article cavity. Thus, in some embodiments, at least a portion of one or more walls may be formed from a gas permeable material. In some of these embodiments, one or more walls of the article cavity may be formed from a gas permeable material. In some embodiments, one or more slots may be formed in one or more walls to allow air to enter the article cavity. The one or more slots may have any suitable shape and size that allows air to enter the article cavity. For example, at least one of the one or more slots may have an L-shape, an S-shape, a T-shape, or an I-shape.

[0054] In some embodiments, a portion of one or more walls of the article cavity is formed from a gas permeable material or includes one or more slots, and a different portion of the one or more walls includes or forms one of either the first electrode or the second electrode.

[0055] The article cavity may have any suitable shape and size. In particular, the article cavity may have a shape and size complementary to the aerosol-generating article. In other words, the article cavity may have the same or similar shape and dimensions as at least a portion of the aerosol-generating article. The article cavity may be configured to receive the aerosol-generating article with a tight fit. In other words, the walls of the article cavity may be in contact with the aerosol-generating article when the aerosol-generating article is received within the article cavity.

[0056] The article cavity may have any suitable transverse cross-section. For example, the article cavity may have a circular, oval, rectangular, square, triangular, or other polygonal transverse cross-sectional shape.

[0057] In some embodiments, the article cavity is substantially cuboid.

[0058] In some embodiments, the article cavity is substantially cylindrical in shape.

[0059] In some embodiments, the article cavity is substantially frusto-conical. In some embodiments, the width or diameter of one end of the article cavity is greater than the width or diameter of the other end of the article cavity. In other words, the article cavity may taper from one end to the other. Providing an article cavity with one end narrower than the other end may enable the article cavity to retain the aerosol-generating article in the article cavity under the influence of gravity alone.

[0060] The article cavity may comprise an opening. The article cavity may be configured to receive an aerosol-generating article containing the aerosol-forming substrate through the opening. The article cavity may comprise an open end. The article cavity may be configured to receive an aerosol-forming article containing the aerosol-forming substrate through the open end.

[0061] In some embodiments, the article cavity may comprise a movable closure. The movable closure may be configured to substantially close an open end of the article cavity. When the movable closure is arranged to substantially close an open end of the article cavity, the movable closure may substantially prevent the aerosol-forming article from being removable from the article cavity. The movable closure may be rotatably movable to close the open end of the article cavity. The movable closure may be slidably movable to close the open end of the article cavity. The movable closure may be removably coupleable to the open end of the article cavity to substantially close the open end of the article cavity.

[0062] In embodiments including a movable occluding portion, the movable occluding portion may include one of the first electrode and the second electrode. The movable occluding portion may include the first electrode. The movable occluding portion may include the second electrode.

[0063] In embodiments including a movable closure, the movable closure may include electrical contacts for electrically connecting to an electrode of the aerosol-generating article when the aerosol-generating article is received within the article cavity. The movable closure may include electrical contacts electrically connected to an oscillator circuit. The movable closure may include electrical contacts electrically connected to the oscillator circuit by a flexible circuit.

[0064] In some embodiments, the article cavity may include two open ends. For example, the article cavity may include a first open end and a second open end opposite the first end. Advantageously, providing the article cavity with two open ends may allow air to be drawn through the article cavity between the open ends.

[0065] In some embodiments, the article cavity may include an open end and a closed end. The closed end may enable the article cavity to retain an aerosol-generating article within the article cavity.

[0066] In some embodiments, the article cavity is substantially frustoconical, with a first end narrower than the second end. In these embodiments, the first end of the article cavity may be open and the second end of the article cavity may also be open. This may allow air to be drawn through the article cavity from the first end to the second end. In these embodiments, the aerosol-generating article configured to be received in the article cavity may comprise a fluid-permeable first end exterior surface and a fluid-permeable second end exterior surface. The fluid-permeable first end and second end exterior surfaces of the aerosol-generating article may allow air to flow through the article cavity between the first end and the second end when the aerosol-generating article is received in the article cavity.

[0067] The article cavity may have any suitable shape and size. The article cavity may have a length of about 10 millimeters to about 100 millimeters, about 20 millimeters to about 90 millimeters, or about 25 millimeters to about 80 millimeters. In some preferred embodiments, the article cavity may have a length of about 33 millimeters, about 34 millimeters, about 35 millimeters, about 36 millimeters, about 37 millimeters, about 38 millimeters, 39 millimeters, about 40 millimeters, about 41 millimeters, or about 42 millimeters. The article cavity may have a width or diameter of about 5 millimeters to about 70 millimeters, or about 10 millimeters to about 60 millimeters, or about 10 millimeters to about 50 millimeters. In some preferred embodiments, the article cavity may have a width or diameter of about 35 millimeters, about 36 millimeters, about 37 millimeters, about 38 millimeters, 39 millimeters, about 40 millimeters, about 41 millimeters, about 42 millimeters, about 43 millimeters, about 44 millimeters, or about 45 millimeters.

[0068] The term "length" as used herein refers to the maximum longitudinal dimension of a shisha device, a component of a shisha device, an aerosol-generating article, or a component of an aerosol-generating article between the base or bottom end and the top end. The term "width" or "diameter" as used herein refers to the maximum transverse dimension of a shisha device, a component of a shisha device, an aerosol-generating article, or a component of an aerosol-generating article. For example, if an aerosol-generating article has a frustoconical shape, the width or diameter of the aerosol-generating article is the width or diameter of the base of the frustoconical shape, which is the widest part of the aerosol-generating article at any point along the length of the aerosol-generating article. The transverse dimension is the dimension measured in a direction measured in a direction transverse to the longitudinal direction, and the longitudinal direction is the direction in which the longitudinal dimension is measured. The term "transverse cross section" as used herein refers to a cross section taken along a transverse plane.

[0069] The terms "top" and "bottom" as used herein refer to the relative positions of an element or part of an element of a shisha device, a component of a shisha device, an aerosol generating article or a component of an aerosol generating article.

[0070] The article cavity may be located in the heating unit. The heating unit may include the article cavity. The heating unit may include one or more of the first electrode, the second electrode, and one or more electrical contacts for electrical connection to the electrodes of an aerosol-generating article received in the article cavity. The heating unit may further include one or more of a control circuit including an oscillator circuit and a power source. The heating unit may further include one or more electrical connectors for electrically connecting one or more electrical components to the heating unit, such as the control circuit and the power source.

[0071] The heating unit may comprise one or more housings formed from a material that is opaque to RF fields. It is preferred that all of the exterior walls of the heating unit are formed from a material that is opaque to RF fields. However, it is understood that the heating unit may comprise a housing having one or more exterior walls formed from a material that is transparent to RF fields. In some embodiments, it is preferred that all of the exterior walls of the heating unit are formed from a material that is transparent to RF fields. The heating unit may comprise an opening that allows an aerosol-generating article to be inserted into the article cavity. The heating unit may comprise a movable closure, such as a lid or door, that is movable between an open position and a closed position. The open position may allow an aerosol-generating article to be inserted into the article cavity, and the closed position may substantially prevent or inhibit removal of the aerosol-generating article from the article cavity. The movable closure may be movably coupled, e.g., rotatably connected or slidably coupled, to an exterior wall of the housing of the heating unit. The movable closure may be removably coupled to an exterior wall of the housing of the heating unit.

[0072] The shisha device may comprise an air inlet. The air inlet may allow ambient air to be drawn into the shisha device. The device housing of the shisha device may comprise an air inlet. The air inlet may allow ambient air to be drawn into the article cavity. In embodiments where one or more ends of the article cavity are on an exterior surface of the shisha device, the article cavity may comprise an air inlet. In embodiments where the article cavity comprises an open end for receiving an aerosol-generating article, the open end may form the air inlet.

[0073] An airflow path may be defined between the air inlet and the head space outlet. The airflow path may extend through the article cavity. The airflow path may extend from the article cavity into the liquid cavity. The airflow path may extend from the article cavity through an airflow conduit into the liquid cavity below the liquid fill level of the liquid cavity. The airflow path may extend from below the liquid fill level of the liquid cavity to the head space of the liquid cavity and out the head space outlet.

[0074] The airflow path may include one or more convoluted portions. The one or more convoluted portions may extend beyond one or more radiation-shielding elements. In embodiments where the airflow path passes through the article cavity or through the generated RF electromagnetic field, the airflow path may include a convoluted portion beyond one or more radiation-shielding elements to prevent RF radiation from escaping through the air inlet or air outlet. One or more fluid-permeable radiation-shielding elements may be provided in the airflow path. For example, a metal mesh may be provided in the airflow path.

[0075] In some embodiments, the article cavity is configured such that the airflow path through the article cavity is aligned with the airflow conduit. In some embodiments, the article cavity is configured such that the airflow path through the article cavity is aligned substantially perpendicular to one or both of the first electrode and the second electrode. In some embodiments, the article cavity is configured such that the airflow path through the article cavity is aligned substantially parallel to one or both of the first electrode and the second electrode.

[0076] A closed loop control scheme may also be used. The shisha device may include a sensor located in or adjacent to the article cavity, the sensor providing a signal indicative of the temperature in the article cavity, and the shisha device may also include a controller connected to receive the signal from the sensor and connected to control the oscillating circuit in dependence on the signal from the sensor.

[0077] The sensor may include a temperature sensor that directly measures temperature. The sensor may comprise a sampling antenna or multiple sampling antennas configured to detect perturbations in the electromagnetic field in the article cavity that are indicative of the temperature in the article cavity. The dielectric properties of the aerosol-forming substrate change depending on the temperature. The frequency or amplitude, or both the frequency and amplitude, of the electromagnetic field may be adjusted by the controller based on the signal from the sensor to control the heating provided by the device.

[0078] Overheating may be detected by the sensor and underheating may be detected by the sensor. By detecting overheating or underheating, the frequency and amplitude of the electromagnetic field may be adjusted accordingly. The control circuitry of the shisha device may be configured to adjust at least one of the frequency and amplitude of the electromagnetic field based on whether overheating is detected by the sensor or underheating is detected by the sensor.

[0079] A malfunction may be detected by the sensor. If a malfunction is detected, the shisha device may be automatically switched off. It may also be possible to detect the presence of an inappropriate material in the article cavity. If an inappropriate material is detected in the article cavity, the shisha device may be automatically switched off. Similarly, if the signal of the sensor indicates that no aerosol-forming substrate is present in the article cavity, the shisha device may be automatically switched off. In order to automatically switch off the shisha device, the control circuit of the shisha device may be configured to prevent power from being supplied to the oscillation circuit.

[0080] It may be desirable to maintain the temperature within the article cavity within a predetermined temperature range. It may be desirable to maintain the temperature of the aerosol-forming substrate below the temperature of the aerosol-forming substrate combustion product.

[0081] The ability to control the amount of heat provided by the shisha device based on a feedback signal also allows for the use of different aerosol-forming substrates. It may be desirable to heat different aerosol-forming substrates to different temperatures. Thus, providing a mechanism for temperature control allows for optimal conditions to be achieved for different aerosol-forming substrates or different designs of aerosol-forming articles.

[0082] The shisha device may comprise a puff detector configured to detect when a user puffs on the shisha device. As used herein, the term "puff" is used to refer to a user puffing on the shisha device to receive aerosol. The puff detector may comprise a temperature sensor. The puff detector may comprise a pressure sensor. The puff detector may comprise both a temperature sensor and a pressure sensor.

[0083] The shisha device may include a control circuit. The control circuit may be configured to control the power supply to the oscillation circuit. The control circuit may include one or more of a microprocessor, a programmable microprocessor, a microcontroller, and an application specific integrated circuit chip (ASIC) or other electronic circuitry capable of providing control. The control circuit may include further electronic components. For example, in some embodiments, the control circuit may include one or more of a sensor, a switch, and a display element. The control circuit may include an RF power sensor. The control circuit may include a power amplifier.

[0084] In some embodiments, the shisha device is configured to connect to an external power source. For example, the shisha device may be configured to connect to a mains power source.

[0085] In some embodiments, the shisha device comprises a power source. The power source may be a DC power source. The power source may include a battery or another form of charge storage device, such as a capacitor. The power source may include a rechargeable lithium ion battery. In some embodiments, the power source is a rechargeable power source. The shisha device may be configured to connect to an external power source to recharge the rechargeable power source.

[0086] The control circuit may be configured to control the supply of power from the power supply to the oscillator circuit.

[0087] The power source may provide between about 0.5 Watts and about 50 Watts of power. In some embodiments, the power source may provide between about 1 Watt and about 40 Watts, or between about 2 Watts and about 30 Watts of power.

[0088] The shisha device may include a vessel. The liquid cavity may be an interior volume of the vessel. The vessel may be configured to contain a liquid. The vessel may define a liquid cavity. The vessel may include a head space outlet. The vessel may define a liquid fill level. For example, the vessel may include a liquid fill level perimeter. The liquid fill level perimeter is an indicator provided on the vessel to indicate a desired level at which the liquid cavity is intended to be filled with liquid. The head space outlet may be disposed above the liquid fill level. The head space outlet may be disposed above the liquid fill level perimeter. The vessel may include an optically transparent portion. The optically transparent portion may allow a user to observe the contents contained in the vessel. The vessel may be formed of any suitable material. For example, the vessel may be formed of glass or a hard plastic material. In some embodiments, the vessel is removable from the remainder of the shisha assembly. In some embodiments, the vessel is removable from the aerosol-generating portion of the shisha assembly. Advantageously, a removable vessel allows a user to fill the liquid cavity with liquid, empty the liquid cavity of liquid, and clean the vessel.

[0089] The vessel may be filled by a user to a liquid fill level. The liquid preferably comprises water. The liquid may comprise water infused with one or more of a colorant and a flavorant. For example, the water may be infused with one or both of a botanical infusion and an herbal infusion.

[0090] The vessel may have any suitable shape and size. The liquid cavity may have any suitable shape and size. The headspace may have any suitable shape and size.

[0091] Typically, the shisha device according to the present disclosure is intended to be placed on a surface during use, rather than being carried by a user. Thus, the shisha device according to the present disclosure may have a particular use orientation, or a range of orientations, in which the device is intended to be oriented during use. Thus, the terms "above" and "below" as used herein refer to the relative positions of features of the shisha device or shisha system when the shisha device or shisha system is held in a use orientation.

[0092] In some embodiments, the article cavity is disposed above the liquid cavity. In these embodiments, the airflow conduit may extend from the article cavity below the liquid fill level of the liquid cavity. Advantageously, this may ensure that volatile compounds released from the aerosol-forming substrate in the article cavity are delivered from the article cavity to the liquid in the liquid cavity, rather than to the head space above the liquid cavity. In these embodiments, the airflow conduit may extend from the aerosol cavity through the head space of the liquid cavity above the liquid fill level into the liquid cavity and into the liquid below the liquid fill level. The airflow conduit may extend into the liquid cavity through the top or upper end of the liquid cavity.

[0093] In some embodiments, the article cavity is disposed below the liquid cavity. In these embodiments, a one-way valve may be disposed between the article cavity and the liquid cavity. The one-way valve may prevent liquid from the liquid cavity from entering the article cavity under the influence of gravity. In these embodiments, the one-way valve may be provided in an airflow conduit that extends from the article cavity into the liquid cavity. In these embodiments, the airflow conduit may extend below the liquid fill level in the liquid cavity. The airflow conduit may extend into the liquid cavity through a bottom end of the liquid cavity.

[0094] The present disclosure also provides a shisha device.

[0095] In some embodiments, the shisha device includes a liquid cavity, an article cavity, a first electrode, a second electrode, and an oscillator circuit. The liquid cavity is configured to contain a liquid, the liquid cavity comprising a head space outlet. The article cavity is configured to receive an aerosol-generating article, and the article cavity is in fluid communication with the liquid cavity. The first electrode and the second electrode are disposed in or around the article cavity, and the second electrode is spaced apart from the first electrode such that when the aerosol-generating article is received in the article cavity, at least a portion of the aerosol-generating article is received between the first electrode and the second electrode. The oscillator circuit is connected to the first electrode and the second electrode, and is configured to provide a radio frequency (RF) alternating voltage to the first electrode and the second electrode to heat the aerosol-forming substrate when the aerosol-generating article is received in the cavity between the first electrode and the second electrode.

[0096] In some embodiments, the shisha device includes a liquid cavity, an article cavity, a first electrode, an electrical contact, and an oscillation circuit. The liquid cavity is configured to contain a liquid, and the liquid cavity includes a head space outlet. The article cavity is configured to receive an aerosol-generating article, and the article cavity is in fluid communication with the liquid cavity. The first electrode may be disposed in or around the article cavity. The electrical contact may be disposed in the article cavity to electrically connect to the second electrode when an aerosol-generating article including the second electrode is received in the article cavity. The oscillation circuit is connected to the first electrode and the second electrode, and is configured to supply a radio frequency (RF) alternating voltage to the first electrode and the electrical contact. When an aerosol-generating article including an aerosol-forming substrate and a second electrode is received in the article cavity, the RF alternating voltage supplied to the electrical contact is supplied to the second electrode, and the aerosol-forming substrate between the first electrode and the second electrode is heated.

[0097] In some embodiments, the shisha device includes a liquid cavity, an article cavity, a first electrical contact, a second electrical contact, and an oscillation circuit. The liquid cavity is configured to contain a liquid, and the liquid cavity includes a head space outlet. The article cavity is configured to receive an aerosol-generating article, and the article cavity is in fluid communication with the liquid cavity. The first electrical contact may be disposed in or around the article cavity, and the first electrical contact is disposed to electrically connect to a first electrode of the aerosol-generating article received in the article cavity. The second electrical contact may be disposed in or around the article cavity to electrically connect to a second electrode of the aerosol-generating article received in the article cavity. The oscillation circuit is connected to the first electrical contact and the second electrical contact, and is configured to supply a radio frequency (RF) AC voltage to the first electrode and the electrical contacts. When an aerosol-generating article including an aerosol-forming substrate and a first electrode and a second electrode is received in the article cavity, an RF alternating voltage supplied to the first electrical contact is supplied to the first electrode and an RF alternating voltage supplied to the second electrical contact is supplied to the second electrode, heating the aerosol-forming substrate between the first electrode and the second electrode.

[0098] The present disclosure also provides an aerosol generating article for use with a shisha device, as previously described.

[0099] The aerosol generating article may be any suitable type of aerosol generating article for use with a shisha device. An aerosol generating article specifically designed for use with a shisha device may be referred to as a cartridge for the shisha device.

[0100] The aerosol-generating article may have any suitable shape and size. In particular, the aerosol-generating article may have a shape and size that is complementary to the article cavity of the shisha device.

[0101] The aerosol-generating article may have any suitable transverse cross-section, for example, the aerosol-generating article may have a circular, oval, rectangular, square, triangular, or other polygonal transverse cross-sectional shape.

[0102] In some embodiments, the aerosol-generating article is substantially cylindrical in shape.

[0103] In some embodiments, the aerosol-generating article is substantially cubic.

[0104] In some embodiments, the aerosol-generating article is substantially frusto-conical. In some embodiments, the width or diameter of a first end of the aerosol-generating article is greater than the width or diameter of a second end of the aerosol-generating article opposite the first end. In other words, the aerosol-generating article may taper from the first end to the second end. By providing an aerosol-generating article with a second end that is narrower than the first end, the aerosol-generating article can be held in a complementary article cavity under the influence of gravity.

[0105] The aerosol-generating article may have a length of about 10 millimeters to about 100 millimeters, about 20 millimeters to about 90 millimeters, or about 25 millimeters to about 80 millimeters. In some preferred embodiments, the aerosol-generating article may have a length of about 33 millimeters, about 34 millimeters, about 35 millimeters, about 36 millimeters, about 37 millimeters, about 38 millimeters, 39 millimeters, about 40 millimeters, about 41 millimeters, or about 42 millimeters. The aerosol-generating article may have a width or diameter of about 5 millimeters to about 70 millimeters, or about 10 millimeters to about 60 millimeters, or about 10 millimeters to about 50 millimeters. In some preferred embodiments, the aerosol-generating article may have a width or diameter of about 35 millimeters, about 36 millimeters, about 37 millimeters, about 38 millimeters, 39 millimeters, about 40 millimeters, about 41 millimeters, about 42 millimeters, about 43 millimeters, about 44 millimeters, or about 45 millimeters.

[0106] The aerosol-generating article may include one or both of a first electrode and a second electrode. In some embodiments, the aerosol-generating article includes one of a first electrode and a second electrode. In some embodiments, the aerosol-generating article includes a first electrode and a second electrode.

[0107] The electrode may form at least a portion of the outer surface of the aerosol-generating article. The electrode may form a portion of the outer surface of the aerosol-generating article. In some embodiments, at least a portion of the electrode may contact the aerosol-forming substrate. In some embodiments, at least a portion of the electrode may be embedded in the aerosol-forming substrate. In other words, at least a portion of the electrode may be substantially surrounded by the aerosol-forming substrate. When at least a portion of the electrode is embedded in the aerosol-forming substrate, a portion of the electrode is not surrounded by the aerosol-forming substrate such that the electrode can contact an electrical contact of the shisha device when the aerosol-generating article is received in the article cavity.

[0108] When the aerosol-generating article includes both a first electrode and a second electrode at the outer surface of the aerosol-generating article, an electrically insulating element may be disposed on the outer surface of the aerosol-generating article between the first electrode and the second electrode. The electrically insulating element may ensure that the first electrode and the second electrode are not in electrical contact. In some of these embodiments, at least a portion of the first electrode may contact the aerosol-forming substrate. In some of these embodiments, at least a portion of the second electrode may contact the aerosol-forming substrate.

[0109] As used herein, "conductivity" refers to a conductivity of 1×10 -4 Electrically insulating means made of a material having a resistivity of less than 1×10 ohm. 4 This means that it is made of a material that has a resistivity of at least an ohm-meter.

[0110] The aerosol-generating article comprises an aerosol-forming substrate. The aerosol-forming substrate may be enclosed in a wrapper or container. In some embodiments, the aerosol-forming substrate may be completely covered with a coating.

[0111] The wrapper may define a substrate cavity. The aerosol-forming substrate may be disposed in the substrate cavity within the wrapper.

[0112] In some embodiments, at least a portion of the wrapper may comprise a conductive material. In some embodiments, the entire wrapper may comprise a conductive material. The conductive material may form one of the first electrode and the second electrode. The conductive material may form both the first electrode and the second electrode. When the wrapper comprises a first portion formed from a conductive material that forms the first electrode and a second portion formed from a conductive material that forms the second electrode, the wrapper may also include a portion formed from an electrically insulating material disposed between the first portion and the second portion.

[0113] At least a portion of the wrapper may be formed from a gas permeable material to allow air to enter the aerosol-forming substrate and the egress of volatile compounds from the aerosol-generating article. One or more slots may be formed in the wrapper to allow air to enter the aerosol-forming substrate and the egress of volatile compounds from the aerosol-generating article.

[0114] In some embodiments, the portion of the wrapper formed from the electrically conductive material is gas permeable. In these embodiments, the conductive portion of the wrapper may be formed from a metal mesh. In some embodiments, the portion of the wrapper formed from the electrically insulating material may be gas permeable.

[0115] The aerosol-forming substrate may be enclosed in a container. The container may define a substrate cavity. The aerosol-forming substrate may be located within the container in the substrate cavity.

[0116] In some embodiments, the container may comprise an electrically conductive material. In some embodiments, the container may comprise an electrically insulating material.

[0117] In some embodiments, the container may comprise one or more walls. At least one wall of the container may comprise an electrically conductive material. At least one wall of the container may comprise an electrically insulating material. Two opposing walls of the container may comprise an electrically conductive material. All walls of the container may comprise an electrically conductive material. When two opposing walls of the container comprise an electrically conductive material, one or more walls of the container extending between the two opposing walls may comprise an electrically insulating material.

[0118] At least a portion of the container may be fluid-permeable. The fluid-permeable portion of the container may allow volatile compounds released from the aerosol-forming substrate to be released from the aerosol-generating article.

[0119] The walls of the container comprising an electrically insulating material may be fluid permeable. The walls of the container comprising an electrically conductive material may be fluid permeable. For example, the fluid permeable conductive material may be a metal mesh. Thus, at least a portion of the container may be formed from a metal mesh. In some embodiments, the container may be formed from a metal mesh. In some embodiments, one or more slots are formed in the container to allow the ingress of air to the aerosol-forming substrate and the egress of volatile compounds from the aerosol-generating article.

[0120] In some embodiments, at least a portion of the aerosol-forming substrate is coated with a coating. As used herein, the term "coating" refers to a layer of material that covers and adheres to the aerosol-forming substrate. The coating can be applied to cover and adhere to at least a portion of the aerosol-forming substrate by any suitable method known in the art, including, but not limited to, spray painting, vapor deposition, dipping, mass transfer (e.g., brushing or gluing), electrostatic deposition, or any combination thereof.

[0121] In some embodiments, the coating may comprise an electrically conductive material. In some embodiments, the coating may comprise an electrically insulating material.

[0122] One or more areas of the outer surface of the aerosol-forming substrate may be exposed. In other words, one or more areas of the outer surface of the aerosol-forming substrate may not include any coating. This may ensure that volatile compounds released from the aerosol-forming substrate escape from the aerosol-generating article.

[0123] In some embodiments, the covering may include a fluid-permeable material.

[0124] In some embodiments, one or more regions of the exterior surface of the aerosol-forming substrate may be coated with a first coating and one or more regions of the exterior surface of the aerosol-forming substrate may be coated with a second coating.

[0125] One of the first coating and the second coating may include an electrically conductive material. One of the first coating and the second coating may include an electrically insulating material. One of the first coating and the second coating may include an electrically conductive material and the other of the first electrode and the second electrode may include an electrically insulating material. Both the first coating and the second coating may include an electrically conductive material such that the first coating forms the first electrode and the second coating forms the second electrode.

[0126] One of the first coating and the second coating may comprise a fluid-permeable material. Both the first coating and the second coating may comprise a fluid-permeable material. In some preferred embodiments, one of the first coating and the second coating comprises an electrically conductive material and the other of the first coating and the second coating comprises a fluid-permeable, electrically insulating material.

[0127] In some embodiments, at least a portion of the wrapper or container surrounding the aerosol-forming substrate is coated with a coating, which may comprise an electrically conductive material.

[0128] The aerosol-forming substrate can be any suitable substrate capable of releasing a volatile compound when heated.

[0129] In some preferred embodiments, the aerosol-forming substrate is in the form of a suspension. For example, the aerosol-forming substrate may include molasses. As used herein, "molasses" refers to an aerosol-forming substrate composition that includes a suspension having at least about 20 weight percent sugar. For example, molasses may include at least about 25 weight percent sugar, such as at least about 35 weight percent sugar. Typically, molasses contains less than about 60 weight percent sugar, such as less than about 50 weight percent sugar.

[0130] The aerosol-forming substrate is preferably a shisha substrate. As used herein, "shisha substrate" refers to an aerosol-forming substrate composition that includes at least about 20 percent by weight of sugar. The shisha substrate may include molasses. The shisha substrate may include a suspension having at least about 20 percent by weight of sugar.

[0131] The aerosol-forming substrate may be solid or liquid, or may contain both solid and liquid components.

[0132] The aerosol-forming substrate may comprise nicotine. The nicotine-containing aerosol-forming substrate may comprise a nicotine salt matrix. The aerosol-forming substrate may comprise a plant-derived material. The aerosol-forming substrate preferably comprises tobacco. The tobacco-containing material preferably contains volatile tobacco flavour compounds which are released from the aerosol-forming substrate on heating. The aerosol-forming substrate may comprise a homogenised tobacco material. The homogenised tobacco material may be formed by agglomerating particulate tobacco. The aerosol-forming substrate may comprise a non-tobacco-containing material. The aerosol-forming substrate may comprise a homogenised plant-derived material.

[0133] The aerosol-forming substrate may, for example, comprise one or more of a powder, granules, pellets, pieces, spaghetti, strips, or sheets. The aerosol-forming substrate may contain one or more of herbal leaves, tobacco leaves, tobacco stem pieces, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. The tobacco may be flame-cured.

[0134] The aerosol-forming substrate may include at least one aerosol former. Suitable aerosol formers include compounds or mixtures of compounds that facilitate the formation of a dense, stable aerosol during use and that are substantially resistant to thermal decomposition at the operating temperature of the shisha device. Suitable aerosol formers are well known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate, etc.), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.). Particularly preferred aerosol formers are polyhydric alcohols or mixtures thereof (such as triethylene glycol, 1,3-butanediol, and most preferably glycerin). The aerosol former may be propylene glycol. The aerosol-forming substrate may include any suitable amount of aerosol former. For example, the aerosol former content of the substrate may be 5 percent or more on a dry weight basis, and preferably greater than 30 percent on a dry weight basis. The aerosol former content may be less than about 95 percent on a dry weight basis. Preferably, the aerosol former content is up to about 55 percent on a dry weight basis.

[0135] The aerosol-forming substrate preferably comprises nicotine and at least one aerosol former. In some embodiments, the aerosol former is glycerin or a mixture of glycerin and one or more other suitable aerosol formers (such as those described above). In some embodiments, the aerosol former is propylene glycol.

[0136] The aerosol-forming substrate may include other additives and ingredients, such as flavorings. In some embodiments, the aerosol-forming substrate includes one or more sugars in any suitable amount. Preferably, the aerosol-forming substrate includes invert sugar. Invert sugar is a mixture of glucose and fructose obtained by splitting sucrose. Preferably, the aerosol-forming substrate includes about 1 weight percent to about 40 weight percent of a sugar, such as invert sugar. In some embodiments, the one or more sugars may be mixed with a suitable carrier, such as corn starch or maltodextrin.

[0137] In some embodiments, the aerosol-forming substrate comprises one or more sensory enhancers.Suitable sensory enhancers include flavorants and sensates (such as cooling agents).Suitable flavorants include natural or synthetic menthol, peppermint, spearmint, coffee, tea, spices (such as cinnamon, clove, ginger, or combinations thereof), cocoa, vanilla, fruit flavors, chocolate, eucalyptus, geranium, eugenol, agave, juniper, anethole, linalool, and any combination thereof.

[0138] Any suitable amount of aerosol-forming substrate (e.g., molasses or tobacco substrate) may be provided in the aerosol-generating article. In some preferred embodiments, from about 3 grams to about 25 grams of aerosol-forming substrate are provided in the aerosol-generating article. The cartridge may contain at least 6 grams, at least 7 grams, at least 8 grams, or at least 9 grams of aerosol-forming substrate. The cartridge may contain up to 15 grams, up to 12 grams, up to 11 grams, or up to 10 grams of aerosol-forming substrate. Preferably, from about 7 grams to about 13 grams of aerosol-forming substrate are provided in the aerosol-generating article.

[0139] The aerosol-forming substrate may be provided on or embedded within a thermally stable carrier. The term "thermally stable" is used herein to denote a material that does not substantially degrade at temperatures to which the substrate is typically heated (e.g., from about 150°C to about 300°C). The carrier may comprise a thin layer of the substrate deposited on a first major surface, or on a second outer major surface, or on both the first and second major surfaces. The carrier may be formed, for example, of paper or paper-like material, non-woven carbon fiber mat, low-mass open mesh metal screen, or perforated metal foil, or any other thermally stable polymeric matrix. Alternatively, the carrier may take the form of a powder, granules, pellets, pieces, spaghetti, strips, or sheets. The carrier may be a non-woven fiber or fiber bundle incorporating tobacco components. The non-woven fiber or fiber bundle may comprise, for example, carbon fiber, natural cellulose fiber, or cellulose derivative fiber.

[0140] In some preferred embodiments, the aerosol-forming substrate may comprise tobacco, sugar, and an aerosol former. In these embodiments, the aerosol-forming substrate may comprise 10 to 40 percent by weight of tobacco. In these embodiments, the aerosol-forming substrate may comprise 20 to 50 percent by weight of sugar. In these embodiments, the aerosol-forming substrate may comprise 25 to 55 percent by weight of aerosol former. In some particularly preferred embodiments, the aerosol-forming substrate comprises 20 to 30 percent by weight of tobacco, 30 to 40 percent by weight of sugar, and 35 to 45 percent by weight of aerosol former. In some preferred embodiments, the aerosol-forming substrate may comprise about 25 percent by weight of tobacco, about 35 percent by weight of sugar, and about 40 percent by weight of aerosol former. In some preferred embodiments, the aerosol-forming substrate may comprise 15 to 30 percent by weight of tobacco, 15 to 30 percent by weight of sugar, and 45 to 55 percent by weight of aerosol former. In these preferred embodiments, the tobacco may be flue-cured tobacco. In these preferred embodiments, the sugar may be sucrose or invert sugar. In these preferred embodiments, the aerosol former may be propylene glycol.

[0141] It should of course be understood that features described in relation to shisha devices or aerosol generating articles according to the present disclosure may also be applicable to shisha systems.

[0142] It should also be understood that particular combinations of the various features described above may be implemented, provided or used independently.

[0143] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0144] [Figure 1]FIG. 1 is a schematic diagram of a dielectric heating system. [Diagram 2] FIG. 2 is a schematic diagram of a closed loop control system for a shisha system having a dielectric heating system according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 is a schematic diagram of one embodiment of a shisha system having a dielectric heating system. [Figure 4] FIG. 4 is a schematic diagram of a heating unit of a shisha device and an aerosol generating article configured for use with a shisha device according to an embodiment of the present disclosure. [Diagram 5] FIG. 5 is a schematic diagram of a heating unit of a different embodiment of a shisha device according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic diagram of a heating unit of a shisha device and an aerosol generating article configured for use with a shisha device according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a schematic diagram of a heating unit of a shisha device and an aerosol generating article configured for use with a shisha device according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a schematic diagram of a heating unit of a shisha device and an aerosol generating article configured for use with a shisha device according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a schematic diagram of a heating unit of a shisha device and an aerosol generating article configured for use with a shisha device according to an embodiment of the present disclosure. [Figure 10] FIG. 10 is a schematic diagram of one embodiment of a shisha system having the heating unit shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0145] FIG. 1 is a schematic diagram of a heating system using radio frequency electromagnetic radiation (RF), sometimes referred to as dielectric heating. The system includes an oscillator circuit 10 including a radio frequency (RF) signal generator 11 and a phase shift network 12. The system further includes a first electrode 15 connected to a first output of the phase shift network 12 and a second electrode 16 connected to a second output of the phase shift network 12. The second electrode 16 is spaced apart from the first electrode 15 and defines an article cavity 14 between the first electrode 15 and the second electrode 16. The article cavity 14 is configured to receive an aerosol-generating article 18. The aerosol-generating article 18 to be heated is placed in the article cavity 14 and receives radio frequency electromagnetic radiation between the first electrode 15 and the second electrode 16. Polar molecules within the aerosol-generating article 18 align with the oscillating electromagnetic field and are agitated by the electromagnetic field as they oscillate. This causes an increase in temperature of the aerosol-generating article 18. This type of heating has the advantage of being uniform throughout the aerosol-generating article 18 (if the polar molecules are uniformly distributed), and it also has the advantage of reducing the possibility of burning the substrate in contact with the first and second electrodes, as compared to conventional heating elements that transfer heat to the substrate via a conductor.

[0146] Figure 2 shows a control scheme that may be used in any of the embodiments described in Figures 3-10. As previously mentioned, the system includes a control circuit for an oscillator circuit. In the example of Figure 2, the oscillator circuit 10 includes an RF signal generator 10 and a phase shift network 12 for splitting the signal from the RF signal generator 10 into two equal components, 180 degrees out of phase with each other.

[0147] A first output of the oscillator circuit 10 is transmitted to a first electrode 15. A second output 16 of the oscillator circuit 10 is transmitted to a second electrode 16. The first electrode 15 and the second electrode 16 are positioned on opposite sides of the article cavity 14 in a spaced relationship such that the first electrode 15 and the second electrode 16 are not in electrical contact and such that an aerosol-generating article 18 can be positioned in the space between the first electrode 15 and the second electrode 16. The aerosol-generating article 18 is placed in the space between the first electrode 15 and the second electrode 16 in the article cavity 14.

[0148] More specifically, the phase shift network 12 comprises a transformer having a primary winding 21, a first secondary winding 22 and a second secondary winding 23. The primary winding 21 is connected at one end to the output of the RF signal generator 11 and at the other end to ground. One end of the first secondary winding 22 is connected to the first electrode 15 and one end of the second secondary winding 23 is connected to the second electrode 16. The other ends of the first secondary winding 22 and the second secondary winding 23 are connected together and a center tap between the first secondary winding 22 and the second secondary winding 23 is grounded. When power is supplied to the oscillator circuit 10, at any instant in time the voltages at the first electrode 15 and the second electrode 16 are substantially equal but opposite in polarity (i.e., 180 degrees out of phase with each other).

[0149] The control circuitry includes a microcontroller 26 capable of controlling both the frequency and power output of the RF signal generator 11. One or more sensors provide input to the microcontroller 26. The microcontroller 26 adjusts the frequency or power output, or both the frequency and power output, of the RF signal generator 11 based on the sensor input. In the embodiment shown in FIG. 2, there is a temperature sensor 28 positioned to sense the temperature within the article cavity 14. A sampling antenna 30 may be provided in the article cavity 14 as an alternative to or in addition to the temperature sensor 28. The sampling antenna 30 is configured as a receiver and is capable of detecting perturbations in the electromagnetic field in the article cavity 14 that are indicative of the efficiency of energy absorption by the aerosol-forming substrate 20. An RF power sensor 32 is also provided to detect the power output from the RF signal generator 11.

[0150] The microcontroller 26 receives signals from the RF power sensor 32, the temperature sensor 28, and the sampling antenna 30. The signals can be used to determine at least one of whether the temperature in the article cavity 14 is too low, whether the temperature is too high, if there is a defect, and if there is no substrate or a substrate with inadequate dielectric properties.

[0151] Based on the decision made by the microcontroller 26, the frequency and power of the electromagnetic field generated by the RF solid-state transistors are adjusted or the electromagnetic field is turned off. Typically, it is desirable to provide a stable and consistent volume of aerosol, which means maintaining the aerosol-forming substrate within a certain temperature range. However, the desired target temperature may change over time as the composition of the aerosol-forming substrate changes and the temperature of the surrounding system changes. Also, the dielectric properties of the aerosol-forming substrate change with temperature, so it may be necessary to adjust the electromagnetic field as the temperature increases or decreases.

[0152] It will be apparent that features described with respect to one embodiment may also be applied to other embodiments. The described embodiment offers the advantage of uniform, non-contact heating of the aerosol-forming substrate in a manner that can be controlled to provide specific desired aerosol characteristics.

[0153] The embodiment described with reference to FIGS. 3-10 uses the basic heating and control principles illustrated in FIGS.

[0154] FIG. 3 is a schematic diagram of a shisha system according to an embodiment of the present disclosure.

[0155] The shisha device 50 comprises a vessel 52 defining a liquid cavity 54. The vessel 52 is configured to hold a liquid in the liquid cavity 54 and is formed from a rigid, optically transparent material, such as glass. In this embodiment, the vessel 52 has a substantially frustoconical shape and is supported in use at its wide end on a flat, horizontal surface, such as a table or shelf. The liquid cavity 54 is divided into two sections: a liquid section 56 for receiving liquid and a head space 58 above the liquid section 58. A liquid fill level 60 is located at the boundary between the liquid section 56 and the head space 58, the liquid fill level 60 being defined on the vessel 52 by a dashed line marked on the outer surface of the vessel 52. A head space outlet 62 is provided above the liquid fill level 60 on a side wall of the vessel 52. The head space outlet 62 allows fluid to be drawn from the head space 58 out of the liquid cavity 54. A mouthpiece 64 is connected to the head space outlet 62 by a flexible hose 66. A user may suck on mouthpiece 64 to draw fluid from headspace 58 for inhalation.

[0156] The shisha device 50 further comprises a heating unit 70 comprising an electrical oscillator circuit as disclosed herein. Different heating unit examples are discussed in more detail with reference to Figures 4, 5, 6, 7 and 8. The heating unit 70 is disposed above the vessel 52 by an airflow conduit 72. In this embodiment, the heating unit 70 is supported above the vessel 52 by the airflow conduit 72, but it will be understood that in other embodiments, the heating unit 70 may be supported above the vessel 52 by the housing of the shisha device or another suitable support. The airflow conduit 72 extends from the heating unit 70 into the liquid cavity 54 of the vessel 52. The airflow conduit 72 extends through the head space 58, below the liquid fill level 60 and into the liquid section 58. The airflow conduit 72 comprises an outlet 74 in the liquid section 56 of the liquid cavity 54 below the liquid fill level 60. This arrangement allows air to be drawn from the heating unit 70 to the mouthpiece 64. Air may be drawn from the external environment into the device 50, enter the heating unit 70, pass through the heating unit 70, through the airflow conduit 72, into the liquid in the liquid section 56 of the liquid cavity 54, exit the liquid into the headspace 58, exit the vessel from the headspace 58 at the headspace outlet 62, through the hose 66 and drawn to the mouthpiece 64.

[0157] In use, a user may suck on the mouthpiece 64 of the shisha device 50 to receive an aerosol from the shisha device 50. More specifically, an aerosol-generating article including an aerosol-forming substrate may be positioned in an article cavity in a heating unit 70 of the shisha device 50. The heating unit 70 may be operated to heat the aerosol-forming substrate in the aerosol-generating article and release volatile compounds from the heated aerosol-forming substrate. When a user sucks on the mouthpiece 64 of the shisha device 50, the pressure in the shisha device 50 is reduced, which draws the released volatile compounds from the aerosol-forming substrate to the heating unit 70 and into the airflow conduit 72. The volatile compounds are drawn from the airflow conduit 72 at the outlet 74 into the liquid in the liquid section 56 of the liquid cavity 54. The volatile compounds are cooled by the liquid and released into the headspace 58 above the liquid fill level 60. Volatile compounds in the headspace 58 condense to form an aerosol, which is drawn out of the headspace at headspace outlet 62 and into mouthpiece 64 for inhalation by the user.

[0158] Figure 4 shows a schematic diagram of the heating unit 70 of the shisha device 50 of Figure 3 in combination with an aerosol-generating article 90 to form a shisha system according to an embodiment of the present disclosure. Figure 4a shows the heating unit 70 and the aerosol-generating article 90 prior to insertion of the aerosol-generating article 90 into the article cavity 14 of the heating unit 70. Figure 4b shows the aerosol-generating article 90 received in the article cavity 14 of the heating unit 70.

[0159] As shown in Figure 4a, the heating unit 70 comprises an outer housing 71. The outer housing 71 forms a cylindrical tube that is open at one end for insertion of the aerosol-generating article 90 and substantially closed at the opposite end. In this embodiment, the outer housing 71 is formed from a material that is opaque to RF electromagnetic radiation, such as aluminum. However, it will be appreciated that the housing 71 need not be formed from a material that is opaque to RF electromagnetic radiation, but rather in some embodiments may be formed from a material that is substantially opaque to RF electromagnetic radiation, such as a ceramic or plastic material.

[0160] The closure 75 is movable over the open end of the outer housing 71 of the heating unit 70 to substantially close the open end. In this position, the outer housing 71 and the closure 75 define a heating unit cavity. The closure 75 comprises an outer housing similar to the outer housing 71 of the heating unit, formed from a material opaque to RF electromagnetic fields, and sized and shaped to align and engage with the outer housing 71 to close the open end. The closure 75 is rotatably connected to the outer housing 71 by a hinge and is rotatable between an open position shown in FIG. 4a and a closed position shown in FIG. 4b. When the closure 75 is in the open position, the open end of the outer housing 71 is open for inserting and removing an aerosol-generating article 90 from the heating unit cavity. When the closure 75 is in the closed position, the heating unit cavity is surrounded by a material opaque to RF electromagnetic fields such that the RF fields cannot propagate out of the heating unit cavity.

[0161] The sidewall of the outer housing 71 is provided with an air inlet (shown in FIG. 4b) to allow ambient air to enter the heating unit cavity.

[0162] The heating unit 70 is disposed above the vessel 52 of the shisha device 50 on top of the airflow conduit 72. The airflow conduit 72 extends into the heating unit cavity and is fixedly attached to a substantially closed end of an outer housing 71 of the heating unit 70. It will be appreciated that in other embodiments, the heating unit 70 may be removably attached to the airflow conduit 72 such that the heating unit 70 may be removed for cleaning or replacement as needed. An opening 73 is provided in the substantially closed end of the outer housing 71 for fluidly connecting the resonant cavity 80 to the airflow conduit 72.

[0163] An article cavity 14 is defined in the heating unit cavity for receiving an aerosol-generating article 90. The article cavity 14 is defined by a first electrode 15, a second electrode 16 opposite the first electrode 15, and a sidewall 76 extending between the first electrode 15 and the second electrode 16. The article cavity 14 is configured to receive the aerosol-generating article 90 and has a shape and size complementary to the aerosol-generating article 90. The first electrode 15 and the second electrode 16 are substantially identical planar electrodes having a substantially circular shape. The first electrode 15 is secured to an inner surface of the closure 15 such that the first electrode 15 moves with the closure 75 and the second electrode 16 and the sidewall 76 are supported within the heating unit cavity by the airflow conduit 72. The second electrode 16 forms the base of the article cavity cavity 14, the sidewall 76 forms the sidewall of the article cavity 14, and the first electrode 15 forms the top wall of the article cavity 14 when the closure 75 is in the closed position. The sidewall 76 is formed from an electrically insulating material, in this embodiment a ceramic material such as PEEK. Thus, the sidewall 76 prevents the first electrode 15 and the second electrode 16 from making electrical contact with each other.

[0164] 4b, the sidewalls 76 of the article cavity 14 are gas permeable and have slots formed therein to allow air to flow through the article cavity 14 from one side to the other. Thus, the heating unit 70 is configured such that air can be drawn through the air inlet, through the article cavity 14, through the slots in the sidewalls 76 of the article cavity 14, into the heating unit cavity, and from the heating unit cavity, through the openings 73 and into the airflow conduit 72.

[0165] The heating unit 70 further includes an oscillation circuit 10. The oscillation circuit 10 is connected to a power supply (not shown) and a control circuit (not shown) of the shisha device, the control circuit being configured to control the supply of power from the power supply to the oscillation circuit 10. In this embodiment, the power supply is a rechargeable lithium ion battery, and the shisha device 50 includes a power connector that allows the shisha device 50 to be connected to a mains power supply for recharging the power supply. Providing the shisha device 50 with a power supply, such as a battery, makes the shisha device 50 portable and allows it to be used outdoors or in places where a mains power supply is not available.

[0166] The first electrode 15 is electrically connected to the oscillator circuit 10 by a flexible circuit. The second electrode 16 is also electrically connected to the oscillator circuit 10.

[0167] The aerosol-generating article 90 includes an aerosol-forming substrate 92. In this embodiment, the aerosol-forming substrate 92 is a shisha substrate including molasses and tobacco. The aerosol-forming substrate 92 is enclosed within a wrapper 94 formed from a gas-permeable, electrically insulating material, such as tipping paper. The aerosol-generating article 90 has a substantially cylindrical shape, similar to a hockey puck, that is complementary to the shape of the article cavity 14 of the shisha device 50.

[0168] 4b, when the aerosol-generating article 90 is received in the article cavity 14 of the heating unit 70, the circular base of the aerosol-generating article 90 contacts the second electrode 16 of the article cavity 14 and the side of the aerosol-generating article 90 contacts the sidewall 76 of the article cavity 14. When the closure 75 is placed in the closed position, the circular top of the aerosol-generating article 90 contacts the first electrode 15 of the article cavity 14. In this arrangement, the first electrode 15, the second electrode 16 and the aerosol-generating article 90, together with the aerosol-forming substrate 90, form a capacitor, defining a dielectric material between the first electrode 15 and the second electrode 16.

[0169] When a user inhales on the mouthpiece 64 of the shisha device 50, air is drawn into the shisha device 50 through the air inlet of the outer housing 71. The airflow path through the aerosol-generating article 90 and the heating unit 70 is shown by the arrows in FIG. 4b. Air is drawn into the heating unit cavity through the air inlet of the outer housing 71, and from the heating unit cavity into the aerosol-generating article 90 through the sidewall 76 of the article cavity 14. Air is drawn through the aerosol-forming substrate 92, returned to the heating unit cavity through the opposing portion of the sidewall 76 of the article cavity 14, and from the heating unit cavity into the airflow conduit 72 through the opening 73 in the outer housing 71 of the heating unit 70.

[0170] In use, when a user activates the shisha device 50, power is provided from the power source to the oscillation circuit 10. In this embodiment, the shisha device is activated by the user pressing an activation button (not shown) provided on the exterior surface of the heating unit 70. It will be appreciated that in other embodiments, the shisha device may be activated in other manners, such as when a puff sensor provided on the mouthpiece 64 detects that the user is taking a puff on the mouthpiece 64. When power is provided to the oscillation circuit 10, the oscillation circuit generates two substantially equal, out-of-phase RF electromagnetic signals having frequencies between 1 Hz and 300 MHz. One of the signals is provided to the first electrode 15 and the other signal is provided to the second electrode 16.

[0171] The RF electromagnetic signal provided to the first electrode 15 and the second electrode 16 establishes an alternating RF electromagnetic field within the article cavity 14, which inductively heats the aerosol-forming substrate 90, which releases the volatile compound. As described above, the temperature within the article cavity 14 can be regulated using a feedback control mechanism. The temperature within the article cavity 14 can be sensed, or another parameter indicative of the temperature within the substrate cavity can be sensed, to provide a feedback signal to a control circuit of the shisha device 50. The control circuit is configured to adjust the frequency or amplitude, or both the frequency and amplitude, of the RF electromagnetic field to maintain the temperature within the article cavity 14 within a desired temperature range.

[0172] When a user draws on the mouthpiece 64 of the shisha device 50, volatile compounds released from the heated aerosol-forming substrate 90 are entrained in the airflow passing through the aerosol-generating article 90 and are drawn from the aerosol-generating article 90, through the heating unit 70, through the opening 73 and into the airflow conduit 72. As described above, the volatile compounds are drawn from the airflow conduit 72, through the shisha device 50, and out to the mouthpiece 66 and its exterior.

[0173] Figure 5 shows a heating unit 70 and an aerosol-generating article 90 of a shisha device according to another embodiment of the present disclosure. The heating unit 70 shown in Figure 5 is substantially similar to the heating unit 70 shown in Figure 4, and like reference numbers are used to indicate like features. Figure 5a shows the heating unit 70 and the aerosol-generating article 90 prior to insertion of the aerosol-generating article 90 into the article cavity 14 of the heating unit 70. Figure 5b shows the aerosol-generating article 90 received in the article cavity 14 of the heating unit 70.

[0174] The heating unit 70 shown in Figure 5 differs from the heating unit 70 shown in Figure 4 in that the heating unit 70 shown in Figure 5 does not include the first electrode 15 and the second electrode 16. Instead, in this embodiment, the aerosol-generating article 90 comprises the first electrode 15 and the second electrode 16, and the heating unit 70 comprises a first electrical contact 82 and a second electrical contact 84.

[0175] A first electrical contact 82 is secured to the inner surface of the closure 75 in a position similar to the first electrical contact 15 of the embodiment of FIG. 4. A second electrical contact 84 is secured to a base 78 supported within the outer housing 71 in a position similar to the second electrode 16 of the embodiment of FIG. 4. In this embodiment, the article cavity is defined solely by the base 78 and does not include sidewalls. The first electrical contact 82 and the second electrical contact 84 are substantially identical and comprise circular sheets of metal having a diameter significantly smaller than the diameter of the aerosol-generating article 90. The first electrical contact and the second electrical contact are electrically connected to the oscillator circuit 10.

[0176] In this embodiment, the aerosol-generating article 90 has a cylindrical shape substantially similar to the aerosol-generating article 90 of the embodiment of FIG. 4. However, in this embodiment, the aerosol-forming substrate 92 is not enclosed in a wrapper, but rather is contained within a container. The circular bottom and top walls of the container are formed from an electrically conductive material, typically a metal. The circular top wall forms the first electrode 15, and the circular bottom wall forms the second electrode 16. A side wall 98 extends between the periphery of the bottom wall and the periphery of the top wall, and is formed from an electrically insulating material, such as a plastic material, that ensures that the bottom and top walls are not in electrical contact. A number of slots are provided in the side wall 98 to allow air to enter and exit the aerosol-generating article 90.

[0177] As shown in FIG. 5b, when the aerosol-generating article 90 is contained within the article cavity 14 and the closure portion 75 is rotated to the closed position, the first electrical contact 82 contacts the first electrode 15 and electrically connects the first electrode 15 to the oscillator circuit 10, and the second electrical contact 82 contacts the second electrode 15 and electrically connects the second electrode 15 to the oscillator circuit 10.

[0178] Also as shown in Figure 4b, during use, ambient air is drawn into the heating unit 70 through the air inlet and into the aerosol-generating article 90 through the slots in the sidewall 98. Air is drawn out of the aerosol-generating article 90 through the slots in the sidewall 98 and into the airflow conduit 72 where it enters the vessel of the shisha device.

[0179] FIG. 6 shows a heating unit 70 for a shisha device and an aerosol-generating article 90 forming a shisha system according to another embodiment of the present disclosure. The heating unit 70 and the aerosol-generating article 90 shown in FIG. 6 are substantially similar to the heating unit 70 and the aerosol-generating article 90 shown in FIG. 4, and like reference numbers are used to indicate like features. FIG. 6a shows the heating unit 70 and the aerosol-generating article 90 prior to inserting the aerosol-generating article 90 into the article cavity 14 of the heating unit 70. FIG. 6b shows the aerosol-generating article 90 received in the article cavity 14 of the heating unit 70.

[0180] The heating unit 70 shown in FIG. 6 differs from the heating unit 70 shown in FIG. 4 in that the first electrode 15 comprises an elongated, cylindrically shaped electrode and the second electrode 16 comprises an elongated tubular electrode surrounding the first electrode 15.

[0181] The article cavity 14 is defined between the first electrode 15, the second electrode 16, and the base 78, forming an elongated annular cavity that is open at one end and substantially closed at an opposite end. The base 78 is formed from an electrically insulating material, such as PEEK, and includes a plurality of slots to allow air to flow out of the article cavity 14. The base 78 is supported over the flared end of the airflow conduit 72 such that air flowing out of the article cavity 14 flows into the airflow conduit 72, as shown in FIG. 5b. In some embodiments, the flared end of the airflow conduit 72 is an integral part of the airflow conduit 72, however, in this embodiment, the flared end of the airflow conduit 72 is an integral part of the heating unit 70 and is removable from the heating unit 70 and the airflow conduit.

[0182] The heating unit 70 shown in FIG. 6 also differs from the heating unit 70 shown in FIG. 4 in that the outer housing 71 does not include a closure, but rather the article cavity 14 includes a closure 80 hinged to the second electrode 16. The closure 80 is movable between an open position for an aerosol-generating article to be inserted into the article cavity 14, as shown in FIG. 6a, and a closed position for closing the open end of the article cavity 14, as shown in FIG. 6b. The closure 80 is similar to the base 78 in that it is formed from an electrically insulating material, such as PEEK, and includes a number of slots that allow air to enter the article cavity 14 when the closure 80 is in the closed position. The closure 80 further includes an electrical contact 82 centrally located on the closure for contacting the first electrode 15 when the closure 80 is in the closed position, and electrically connecting the first electrode 15 to the oscillator circuit 10. The electrical contact 82 is electrically connected to the oscillator circuit via a flexible circuit. The outer surface of the second electrode 16 is also electrically connected to the oscillator circuit 10.

[0183] In this embodiment, the aerosol-generating article 90 has an elongated tubular shape that is complementary to the shape of the article cavity 14. In particular, the aerosol-forming substrate 92 includes an inner passageway 97 that is sized and shaped complementary to the first electrode 15. When the aerosol-generating article 90 is housed within the article cavity 14, the inner surface of the inner passageway 97 of the aerosol-generating article 90 contacts the outer surface of the first electrode 15 and the outer surface of the aerosol-generating article 90 contacts the inner surface of the second electrode 16.

[0184] FIG. 7 shows a heating unit 70 for a shisha device and an aerosol-generating article 90 forming a shisha system according to another embodiment of the present disclosure. The heating unit 70 and aerosol-generating article 90 shown in FIG. 7 are substantially similar to the heating unit 70 and aerosol-generating article 90 shown in FIG. 6, and like reference numbers are used to indicate like features. FIG. 7a shows the heating unit 70 and aerosol-generating article 90 prior to inserting the aerosol-generating article 90 into the article cavity 14 of the heating unit 70. FIG. 7b shows the aerosol-generating article 90 received in the article cavity 14 of the heating unit 70.

[0185] The heating unit 70 shown in Figure 7 differs from the heating unit 70 shown in Figure 6 in that the heating unit 70 of Figure 7 does not include a second electrode 16, but rather includes a tubular side wall 76 formed from an electrically insulating material such as PEEK, with an electrical contact 84 disposed on the inner surface of the side wall 76. The electrical contact 84 is a substantially point contact electrically connected to the oscillator circuit 10.

[0186] The heating unit 70 shown in FIG. 7 differs from the heating unit 70 shown in FIG. 6 in that the heating unit 70 shown in FIG. 7 does not include a closure.

[0187] The aerosol-generating article 90 shown in Figure 7 differs from the aerosol-generating article 90 shown in Figure 6 in that the aerosol-generating article 90 of Figure 7 comprises a second electrode 16 in the form of a conductive wrapper circumscribing the cylindrical outer surface of an aerosol-forming substrate 92. Furthermore, the aerosol-generating article 90 of Figure 7 does not include an internal passageway. Thus, the first electrode 15 is configured to penetrate the aerosol-forming substrate 92 when the aerosol-generating article 90 is received within the article cavity 14.

[0188] When the aerosol-generating article 90 is received within the article cavity 14 , the second electrode 16 contacts the electrical contact 84 on the inner surface of the cylindrical side wall 76 , electrically connecting the second electrode 16 to the oscillator circuit 10 .

[0189] FIG. 8 shows a heating unit 70 and an aerosol-generating article 90 for a shisha device forming a shisha system according to another embodiment of the present disclosure. The heating unit 70 and the aerosol-generating article 90 shown in FIG. 8 are substantially similar to the heating unit 70 and the aerosol-generating article 90 shown in FIG. 7, and like reference numbers are used to indicate like features. FIG. 8a shows the heating unit 70 and the aerosol-generating article 90 prior to inserting the aerosol-generating article 90 into the article cavity 14 of the heating unit 70. FIG. 8b shows the aerosol-generating article 90 received in the article cavity 14 of the heating unit 70.

[0190] The heating unit 70 shown in Figure 8 differs from the heating unit 70 shown in Figure 7 in that the heating unit 70 of Figure 8 does not include a first electrode 15 or a second electrode 16, but rather includes a first electrical contact 82 and a second electrical contact 84. The first electrical contact 82 is centrally disposed on the base 78 and is substantially similar to the electrical contact 82 on the closure 80 of the embodiment of Figure 6. The second electrical contact 84 is a ring contact that surrounds the inner surface of the sidewall 76.

[0191] The aerosol-generating article 90 shown in Figure 8 differs from the aerosol-generating article 90 shown in Figure 7 in that the aerosol-generating article 90 in Figure 7 includes a first electrode 15 and a second electrode 16. The first electrode 15 includes an elongated cylindrically shaped electrode that extends through the center of the aerosol-forming substrate 92. The second electrode 16 includes a conductive wrapper that surrounds the cylindrically shaped outer surface of the aerosol-forming substrate 92.

[0192] When the aerosol-generating article 90 is received within the article cavity 14, an end of the first electrode 15 of the aerosol-generating article 90 contacts a first electrical contact 82 at the base 78 of the article cavity 14, electrically connecting the first electrode 15 to the oscillator circuit 10. And, the second electrode 16 of the aerosol-generating article contacts a second electrical contact 84 on the inner surface of the cylindrical sidewall 76, electrically connecting the second electrode 16 to the oscillator circuit 10.

[0193] Figures 9 and 10 show a shisha system according to another embodiment of the present disclosure. The shisha system is similar to the shisha system shown in Figure 3, and like reference numbers are used to denote like features.

[0194] The shisha device 50 comprises a vessel 52 defining a liquid cavity 54 divided into two sections, a liquid section 56 containing liquid, and a head space 58 above the liquid section. In this embodiment, the vessel 52 is substantially cylindrical. A liquid fill level 60 is defined at the boundary between the liquid section 56 and the head space 58 and is defined by a dashed line 60 on the exterior surface of the vessel 52. A head space outlet 62 is provided on a side wall of the vessel 52 above the liquid fill level and is configured to allow fluid to be withdrawn from the liquid cavity at the head space 58. A mouthpiece 64 is connected to the head space outlet 62 by a flexible hose 66.

[0195] The vessel 52 is disposed on a heating unit 70, which in this embodiment is a cylindrical unit having a diameter substantially equal to that of the vessel 52. Thus, when the vessel 52 and the heating unit 70 are disposed together for use, the shisha device 50 forms a substantially cylindrical unit.

[0196] Heating unit 70 is removably attached to vessel 52 by screws (not shown) and is shown separate from vessel 52 in Figure 9. Heating unit 70 is substantially similar to the heating unit shown in Figure 6, and like reference numbers are used to indicate like features.

[0197] The heating unit 70 comprises an outer housing 71 formed from a material opaque to RF electromagnetic radiation. The outer housing 71 forms a cylindrical tube that is substantially closed at one end and open at the other end.

[0198] The article cavity 14 is defined within the outer housing 71 between a tubular first electrode 15 and a cylindrically shaped second electrode 16. The tubular first electrode 15 comprises a sheet-like electrode bent into a cylindrical shape defining a cylindrically shaped inner passage. The cylindrically shaped second electrode 16 extends within the inner passage of the first electrode 15 and is coaxially aligned with the first electrode 15 such that the article cavity 14 is substantially annular. The diameter of the inner passage of the first electrode 15 is substantially the same as the diameter of the aerosol-generating article 90 such that the inner surface of the first electrode 15 contacts the outer surface of the aerosol-generating article 90 when the aerosol-generating article 90 is received within the article cavity 14. The second electrode 16 is configured to penetrate the aerosol-generating article 90 when the aerosol-generating article 90 is received within the article cavity 14. By penetrating the aerosol-generating article 90 , the second electrode 16 contacts the aerosol-forming substrate 92 of the aerosol-generating article 90 when the aerosol-generating article 90 is received within the article cavity 14 .

[0199] The article cavity 14 is open at the same end as the open end of the outer housing 71 to allow the aerosol-generating article 90 to be inserted into and removed from the article cavity 14. The opposite end of the article cavity 14 is substantially closed to allow proper placement of the aerosol-generating article 90 within the article cavity 14.

[0200] An air inlet 85 is provided in the outer housing 71, and an air flow passage extends between the air inlet 85 and the substantially closed end of the item cavity 14. The substantially closed end of the item cavity 14 includes a plurality of slots that allow air to be drawn from the air flow passage 86 into the item cavity 14.

[0201] An oscillator circuit 10 is provided within the heating unit 70 beneath the article cavity 14 and the airflow passage 86. The first electrode 15 and the second electrode 16 are electrically connected to the oscillator circuit 10 such that the oscillator circuit can provide an oscillating voltage to each of the first electrode 15 and the second electrode 16. An outer surface of the first electrode 15 is electrically connected to the oscillator circuit 10. A proximal end of the second electrode 16 extends beyond the substantially closed end of the article cavity 14 and through the airflow passage 86 and is electrically connected to the oscillator circuit 10.

[0202] The oscillator circuit 10 is connected to a control circuit (not shown) and a lithium ion battery (not shown), which are arranged and configured to control the supply of power to the oscillator circuit 10 in order to control the RF AC voltage generated by the oscillator circuit 10.

[0203] As shown in FIG. 10, the airflow conduit 72 extends from the vessel 52 into the article cavity 14 and fluidly connects the article cavity 14 to the liquid section 56 of the vessel 52. The airflow conduit 72 extends to a position in the liquid section 56 below the liquid fill level 60. A one-way valve (not shown) is disposed in the airflow conduit 72 at an opening 73 between the heating unit 70 and the vessel 52 to prevent liquid from flowing from the liquid section 56 through the airflow conduit 72 into the article cavity 14 under the influence of gravity. The one-way valve does not allow fluid to flow from the vessel 52 into the heating unit 70 and also requires a minimum pressure to be reached in order for fluid to flow from the heating unit 70 to the vessel 52. The end of the airflow conduit 72 that extends into the heating unit 70 flares outward to contact the outer periphery of the open end of the article cavity 14. The flared end of the airflow conduit 72 may be formed from a resilient material, such as silicone, such that the flared end of the airflow conduit 72 forms an airtight seal with the periphery of the open end of the article cavity 14 .

[0204] In use, when a user puffs on the mouthpiece 64, ambient air is drawn into the shisha device 50 through the air inlet 85 and the air flow passage 86 and into the article cavity 14. A puff sensor (not shown) provided in the article cavity 14 and connected to a control circuit and a battery senses that the user is puffing on the mouthpiece 64 as air flows into the article cavity 14. When the puff sensor detects that the user is puffing on the mouthpiece 64, the control circuit provides power from the battery to the oscillator circuit 10 to provide a first RF AC voltage to the first electrode 15 and a second RF AC voltage, 180 degrees offset from the first RF AC voltage, to the second electrode 16 to heat an aerosol-forming substrate of the aerosol-generating article 90 in the article cavity 14. Volatile compounds are released from the heated aerosol-forming substrate. The air drawn into the article cavity 14 entrains the released volatile compounds, which are drawn into the airflow conduit 72, through the one-way valve, and into the liquid section 56 of the vessel 52. The volatile compounds are cooled by the liquid in the liquid section 56 and are released from the liquid into the headspace 58, where they condense to form an aerosol. The aerosol is drawn from the headspace 58 through the headspace outlet 62, along the hose 66 and to the mouthpiece 64 for inhalation by the user.

[0205] It will be understood that the above-mentioned embodiments are only exemplary embodiments, and various other embodiments are also envisioned according to the present disclosure. For example, it will be understood that the above-mentioned heating unit embodiment can be used with any suitable design of the shisha device, such as the device shown in Figures 3 and 10. For example, it will be understood that the vessel, aerosol-forming article, and any other features of the shisha system according to the present disclosure can be any other shape and size as desired. For example, the liquid in the liquid section of the shisha device is preferably water, but can be another suitable liquid.

Claims

1. A shisha system, comprising: an aerosol-generating article comprising an aerosol-forming substrate; a first electrode and a second electrode; A shisha device, comprising: a liquid cavity configured to contain a liquid, the liquid cavity having a head space outlet; an article cavity configured to receive the aerosol-generating article, the article cavity being in fluid communication with the liquid cavity; and and an oscillator circuit configured for connection to the first electrode and the second electrode; A shisha system, wherein the oscillator circuit is configured to supply a radio frequency (RF) alternating voltage to the first electrode and the second electrode, and the RF voltage between the first electrode and the second electrode generates an alternating radio frequency (RF) electromagnetic field between the first electrode and the second electrode to heat the aerosol-forming substrate when the aerosol-generating article is received in the article cavity.

2. The shisha system of claim 1 , wherein the first electrode and the second electrode are positioned to contact the aerosol-generating article when the aerosol-generating article is received within the article cavity.

3. 3. The shisha system of claim 1 or 2, wherein the second electrode is spaced apart from the first electrode such that at least a portion of the aerosol-forming substrate is received between the first electrode and the second electrode.

4. The shisha system of claim 1 , 2 or 3 , wherein the shisha device comprises the first electrode and the second electrode, the first electrode and the second electrode being disposed within or around the article cavity.

5. the aerosol-generating article comprises the first electrode and the second electrode, at least a portion of the aerosol-forming substrate being positioned between the first electrode and the second electrode; The shisha device includes a first electrical contact for electrically connecting the first electrode to the oscillator circuit; The shisha system of claim 1 , 2 or 3 , wherein the shisha device includes a second electrical contact for electrically connecting the second electrode to the oscillator circuit.

6. the shisha device includes one of the first electrode and the second electrode; the aerosol-generating article comprising the other of the first electrode and the second electrode; The shisha system of claim 1 , 2 or 3 , wherein the shisha device further comprises an electrical contact for electrically connecting the other of the first electrode and the second electrode to the oscillator circuit.

7. The shisha system of any one of claims 1 to 6, wherein one or more slots are formed in at least one of the first electrode and the second electrode.

8. The shisha system according to any one of claims 1 to 7, wherein the first electrode and the second electrode are substantially planar, and the second electrode is disposed substantially parallel to the first electrode.

9. The shisha system according to any one of claims 1 to 8, wherein the first electrode is a tubular electrode and the second electrode is disposed within the tubular first electrode.

10. A shisha device, comprising: a liquid cavity configured to contain a liquid, the liquid cavity having a head space outlet; an article cavity for receiving an aerosol-generating article comprising an aerosol-forming substrate, said article cavity being in fluid communication with said liquid cavity; a first electrode and a second electrode, the first electrode and the second electrode being disposed within or around the article cavity; A shisha device comprising: an oscillator circuit connected to the first electrode and the second electrode and configured to supply a radio frequency (RF) alternating voltage to the first electrode and the second electrode, the RF voltage between the first electrode and the second electrode generating an alternating radio frequency (RF) electromagnetic field between the first electrode and the second electrode for heating the aerosol-forming substrate when the aerosol-generating article is received in the article cavity between the first electrode and the second electrode; and a transmitter circuit.

11. A shisha device, comprising: a liquid cavity configured to contain a liquid, the liquid cavity having a head space outlet; an article cavity for receiving an aerosol-generating article, said article cavity being in fluid communication with said liquid cavity; a first electrode disposed within or around the article cavity; an electrical contact disposed in or about the article cavity to electrically connect to the second electrode when an aerosol-generating article including the second electrode is received within the article cavity; and an oscillator circuit connected to the first electrode and the electrical contacts and configured to supply a radio frequency (RF) alternating voltage to the first electrode and the electrical contacts.

12. A shisha device, comprising: a liquid cavity configured to contain a liquid, the liquid cavity having a head space outlet; an article cavity for receiving an aerosol-generating article, said article cavity being in fluid communication with said liquid cavity; a first electrical contact disposed within or about the article cavity and configured for electrical connection to a first electrode received within the article cavity; a second electrical contact disposed within or about the article cavity and configured for electrical connection to a second electrode received within the article cavity; and an oscillator circuit connected to the first electrical contact and the second electrical contact and configured to supply a radio frequency (RF) alternating voltage to the first electrical contact and the second electrical contact.

13. 1. An aerosol generating article for an electrically heated shisha system, comprising: a first electrode and a second electrode spaced apart from the first electrode to define a substrate cavity; an aerosol-forming substrate disposed within the substrate cavity, the aerosol-forming substrate being a shisha substrate comprising at least 20 weight percent sugar.

14. 14. The aerosol-generating article of claim 13, wherein the first electrode and the second electrode are substantially planar, and the second electrode is disposed substantially parallel to the first electrode.

15. 14. The aerosol-generating article of claim 13, wherein the first electrode is a tubular electrode and the second electrode is disposed within the first electrode.

16. 16. An aerosol-generating article according to any one of claims 13 to 15, wherein one or more slots are formed in at least one of the first electrode and the second electrode.

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