Patent Description:
A flavor inhaler (smoking article), by which flavor is enjoyed without combusting a flavor source such as tobacco, has been proposed instead of a cigarette. <CIT> discloses a flavor inhaler including an aerosol generation source that generates aerosol without combusting. The flavor inhaler has a cooling element that cools the aerosol generated at the aerosol generation source.

<CIT> is related to the preamble of claim <NUM>, and <CIT>, <CIT>, <CIT> and <CIT> show similar flavor inhalers.

The invention is defined in claim <NUM> and its appended dependent claims. A first feature is summarized as a flavor inhaler comprising: a flavor source configured to generate flavor without combusting; a cylindrical holding member including at least the flavor source inside; a flow path that is provided in the cylindrical holding member and that is extending from the flavor source toward a suction port for sucking the flavor; and a cooling layer provided only downstream of the flavor source, wherein the cooling layer is provided on an inner surface of the cylindrical holding member, and faces the flow path. The cooling layer preferably surrounds a second flow path, in at least a part of section of the second flow path.

A second feature is summarized as the flavor inhaler according to the first feature, wherein the cylindrical holding member has a hole to directly flow external air into the flow path, and at least a part of the cooling layer is provided downstream of the hole. Here, "directly flow" means that external air flows into the flow path without passing a flavor source.

A third feature is summarized as the flavor inhaler according to the second feature, wherein the hole is formed to flow external air into the flow path toward a direction crossing to a direction in which the flow path extends.

A fourth feature is summarized as the flavor inhaler according to the second feature or third feature, wherein the hole is provided on an opposite side to the suction port with respect to a center of the cylindrical holding member in the direction in which the flow path extends.

A fifth feature is summarized as the flavor inhaler according to any one of the second feature to the fourth feature, wherein a plurality of the holes are provided in a circumferential direction of the cylindrical holding member at intervals.

A sixth feature is summarized as the flavor inhaler according to the fifth feature, wherein one of the holes is arranged at a position displaced from a straight line connecting another one of the plurality of holes and a center axis of the cylindrical holding member.

A seventh feature is summarized as the flavor inhaler according to the first feature to the sixth feature, further comprising a first thermal conductor that transmits heat generated by a combustion heat source to the flavor source, the combustion heat source provided at an ignition end of the cylindrical holding member, wherein the cooling layer is separated from the first thermal conductor.

An eighth feature is summarized as the flavor inhaler according to the seventh feature, wherein the cylindrical holding member has a hole to directly flow external air into the flow path, and the hole is provided between the first thermal conductor and the cooling layer.

A ninth feature is summarized as the flavor inhaler according to the seventh feature or the eighth feature, wherein the cooling layer is formed by a same material as a material configuring the first thermal conductor.

A tenth feature is summarized as the flavor inhaler according to any one of the first feature to the ninth feature, wherein the cooling layer defines a single channel to pass the flavor.

An eleventh feature is summarized as the flavor inhaler according to any one of the first feature to the tenth feature, wherein inside of the cooling layer is hollow. Here, "hollow" means that any member is not present inside the cooling layer, other than a filter provided to the suction port.

A twelfth feature is summarized as the flavor inhaler according to any one of the first feature to the eleventh feature, wherein the cooling layer has a length equal to or longer than a half length of the flow path in the direction in which the flow path extends.

Embodiments are described below. In the description of the drawings below, same or similar reference numerals are given to same or similar parts. It should be noted that, however, the drawings are schematic, in which a ratio or the like of each dimension may differ from that in actuality.

Therefore, a specific dimension or the like should be determined in consideration of the following description. Naturally, even between the drawings, there is included a part in which a relation or a ratio of dimensions of those may differ from each other.

A flavor inhaler according to an embodiment includes: a flavor source that generates flavor without combusting; a cylindrical holding member including at least the flavor source inside; a flow path that is provided in the cylindrical holding member and extending from the flavor source toward a suction port where the flavor is sucked; and a cooling layer provided only downstream of the flavor source. In the flavor inhaler, the cooling layer is provided on an inner surface of the cylindrical holding member, and facing the flow path. Since the cooling layer facing the flow path is provided on the inner surface of the cylindrical holding member, inside of the cylindrical holding member does not need to be filled with a cooling element. For example, it is not necessary to fill inside of the holding member with a cooling element that is curled so as to form many channels, as described in <CIT>. If inside of the cylindrical holding member is filled the cooling element, a ventilation resistance is increased, complicating a design of the ventilation resistance. In this embodiment, inside of the cylindrical holding member does not need to be filled with the cooling element, achieving an easy design of the ventilation resistance.

A flavor inhaler according to a first embodiment is described below. <FIG> is a side view of the flavor inhaler <NUM> according to the first embodiment. <FIG> is a cross-sectional view of the flavor inhaler <NUM> along 2A-2A line in <FIG>. <FIG> is a cross-sectional view of the flavor inhaler <NUM> along 3A-3A line in <FIG>. The flavor inhaler <NUM> has a cylindrical holding member <NUM>, an inside holding member <NUM>, a combustion heat source <NUM>, and a flavor source <NUM>.

The cylindrical holding member <NUM> extends from an ignition end E1 toward a non-ignition end E2. The ignition end E1 is an end on a side provided with the combustion heat source <NUM>. Non-ignition end E2 is an end on a side provided with a suction port <NUM>. The suction port <NUM> is positioned where a user holds in the mouth for sucking a flavor. The cylindrical holding member <NUM> may have, for example, a cylindrical shape or a rectangular cylindrical shape. An opening on the ignition end E1 side of the cylindrical holding member <NUM> is preferably closed. In this embodiment, at least the inside holding member <NUM> and the combustion heat source <NUM> close the opening on the ignition end E1 side of the cylindrical holding member <NUM>. Thus, the flavor inhaler <NUM> is preferably configured such that gas does not enter into the cylindrical holding member <NUM> from the opening on the ignition end E1 side of the cylindrical holding member <NUM>.

The inside holding member <NUM> is provided in the cylindrical holding member <NUM>. However, a part of the inside holding member <NUM> may extend outside of the cylindrical holding member <NUM>. The inside holding member <NUM> retains at least a part of the combustion heat source <NUM> and at least a part of the flavor source <NUM>. The inside holding member <NUM> has the first side wall <NUM> in a cylindrical shape and an introduction port <NUM>. The first side wall <NUM> surrounds at least a part of the flavor source <NUM> and at least a part of the combustion heat source <NUM>. Alternatively, the first side wall <NUM> may surround at least a part of the flavor source <NUM> without surrounding the combustion heat source <NUM>. The introduction port <NUM> is provided so as to introduce air to the flavor source <NUM> in the first side wall <NUM>. The introduction port <NUM> may be formed from a hole formed on the first side wall <NUM>.

The combustion heat source <NUM> is provided on the ignition end E1 side of the cylindrical holding member <NUM>. The combustion heat source <NUM> is composed from a combustible material. The combustible material is, for example, a mixture including a carbon material, an incombustible additive, a binder (an organic binder or an inorganic binder), and water. As the carbon material, it is preferable to use a material from which volatile impurities have been removed by a heat treatment or the like. When a total weight of the combustion heat source <NUM> is <NUM> wt. %, the combustion heat source <NUM> preferably includes a carbonaceous material in a range of <NUM> wt. % to <NUM> wt. %, more preferably includes the carbonaceous material in a range of <NUM> wt. % to <NUM> wt.

The combustion heat source <NUM> is designed such that a part on the ignition end E1 side is burned, but an end part on a non-ignition end E2 side is not burned. Namely, the end part on the non-ignition end E2 side of the combustion heat source <NUM> forms a non-combustion part, while other part of the combustion heat source <NUM> forms a combustion part.

The flavor source <NUM> is provided inside the cylindrical holding member <NUM>, on the non-ignition end E2 side from the combustion heat source <NUM>. The flavor source <NUM> may be adjacent to the combustion heat source <NUM>. The flavor source <NUM> is configured to generate flavor without combusting. To be more precise, the flavor source <NUM> generates flavor by heating with the combustion heat source <NUM>.

As the flavor source <NUM>, for example, a tobacco material can be used. In such a case, the flavor source <NUM> may include general cut tobacco that is used for cigarettes (paper rolled tobacco), and may include granular tobacco that is used for snuff tobacco. The flavor source <NUM> may include glycerin and/or propylene glycol, in addition to the tobacco material. The flavor source <NUM> may include a flavoring agent.

The cylindrical holding member <NUM> has a second side wall <NUM> having a cylindrical shape to surround the first side wall <NUM> of the inside holding member <NUM>. The second side wall <NUM> may extend long from the ignition end E1 side toward the non-ignition end E2 side. The second side wall <NUM> may include, for example, a paper tube formed by deforming a rectangular cardboard into a cylindrical shape.

At least the first side wall <NUM> of the inside holding member <NUM> may be formed by a thermal conductor. Additionally, it is preferable that the inside holding member <NUM> is integrally formed by the thermal conductor. Heat conductivity of this thermal conductor at normal temperature is preferably equal to or more than <NUM> W/(m·K) in a direction along the ignition end E1 to the non-ignition end E2. As the thermal conductor, for example, stainless steel can be used. As the stainless steel, for example, SUS430 may be used. When the inside holding member <NUM> is made from stainless steel, a thickness of the first side wall <NUM> of the inside holding member <NUM> is preferably <NUM> or less.

The second side wall <NUM> of the cylindrical holding member <NUM> may include a first thermal conductor <NUM> facing the inside holding member <NUM>. The first thermal conductor <NUM> is arranged so as to cover at least a part of at least the first side wall <NUM> of the inside holding member <NUM>. The first thermal conductor <NUM> does not need to be directly in contact with the combustion heat source <NUM>.

The first thermal conductor <NUM> promotes the heat conduction from the combustion heat source <NUM> to the flavor source <NUM>. The first thermal conductor <NUM> preferably extends to the non-ignition end E2 side from an end face on the non-ignition end E2 side of the inside holding member <NUM>. The first thermal conductor <NUM> is preferably formed from a metal material excellent in heat conductivity. Heat conductivity of the first thermal conductor <NUM> is preferably higher than heat conductivity of the first side wall <NUM>. For example, the first thermal conductor <NUM> is formed from aluminum.

The second side wall <NUM> of the cylindrical holding member <NUM> has a through-hole <NUM> that is fluidly coupled to external air. The through-hole <NUM> may be provided on the ignition end E1 side from an end part on the non-ignition end E2 side of the flavor source <NUM>.

At least between the first side wall <NUM> and the second side wall <NUM>, a flow-path forming member <NUM> is provided. The flow-path forming member <NUM> defines a first flow path <NUM> inside the cylindrical holding member <NUM>, for allowing external air to flow to the flavor source <NUM>. The flow-path forming member <NUM> may also be formed from a member that is separate from the first side wall <NUM> and the second side wall <NUM>. Alternatively, the flow-path forming member <NUM> may also be formed from a member that is integrally formed on the first side wall <NUM> or the second side wall <NUM>. The first flow path <NUM> connects the through-hole <NUM> of the second side wall <NUM> and the introduction port <NUM> of the inside holding member <NUM>, and passes between the first side wall <NUM> and the second side wall <NUM>.

The inside holding member <NUM> may also have a thermal conductor (not shown) provided on an outer surface of the first side wall <NUM>. This thermal conductor may be arranged so as to cover at least a part of at least the first side wall <NUM> of the inside holding member <NUM>, as with the first thermal conductor <NUM>. This thermal conductor promotes heat conduction from the combustion heat source <NUM> to the flavor source <NUM>. This thermal conductor is preferably formed from a metal material excellent in heat conductivity, for example, formed from aluminum. When the inside holding member <NUM> has a thermal conductor adjacent to the outer surface of the first side wall <NUM>, the first thermal conductor <NUM> does not need to be provided. In this case, the flow-path forming member <NUM> may be provided between the second side wall <NUM> and the thermal conductor on the outer surface of the first side wall <NUM>.

In the cylindrical holding member <NUM>, there is provided a second flow path <NUM> for allowing flavor generated at the flavor source <NUM> to flow to the suction port <NUM>. The second flow path <NUM> connects the flavor source <NUM> and the suction port <NUM> where the flavor generated at the flavor source <NUM> is sucked. The introduction port <NUM> of the inside holding member <NUM> may be provided on the ignition end E1 side from the through-hole <NUM> of the cylindrical holding member <NUM>. Additionally, the first flow path <NUM> is preferably provided only on the ignition end E1 side from the end part on the non-ignition end E2 side of the flavor source <NUM>.

During a puff action of a user, external air enters into the first flow path <NUM> from the through-hole <NUM> (arrow F1 in <FIG>). Then, the external air reaches the flavor source <NUM> through the introduction port <NUM> (arrow F2 in <FIG>). The external air passing through the first flow path <NUM> reaches the flavor source <NUM> without coming into contact with the combustion part of the combustion heat source <NUM>. The air having reached the flavor source <NUM> goes to the suction port <NUM> by passing through the second flow path <NUM>, along with the flavor (arrows F3 and F5 in <FIG>). Since the flavor source <NUM> is heated by the combustion heat source <NUM>, a temperature of the gas passing the flavor source <NUM> to flow into the second flow path <NUM> is high.

The cylindrical holding member <NUM> has a hole <NUM> (hereinafter referred to as a "ventilation hole") that allows external air to directly flow into the second flow path <NUM>. Here, "directly flow" means that external air flows into the second flow path <NUM> without passing the flavor source <NUM>.

The ventilation hole <NUM> may be formed such that gas flows in a crossing direction to an extending direction of the second flow path <NUM> (arrow F4 in <FIG>). For example, the ventilation hole <NUM> may be formed such that gas flows in toward a center axis of the second flow path <NUM>, along a direction substantially orthogonal to the extending direction of the second flow path <NUM>. It is preferable that a plurality of the ventilation holes <NUM> are provided on a circumferential direction of the cylindrical holding member <NUM> at intervals. In this case, the intervals between the ventilation holes <NUM> may be constant. The ventilation hole <NUM> may be provided on an opposite side to the suction port <NUM>, with respect to a center CL of the cylindrical holding member <NUM> in the extending direction of the second flow path <NUM>. The ventilation hole <NUM> is preferably provided between the first thermal conductor <NUM> and a cooling layer <NUM>.

Any one of the plurality of ventilation holes <NUM> is preferably arranged at a position not opposed to another one among the plurality of ventilation holes <NUM>, and is more preferably arranged at a position displaced from a straight line connecting another one among the plurality of ventilation holes <NUM> and a center axis CA of the cylindrical holding member <NUM> (see <FIG>). In this case, each of the ventilation holes <NUM> is not arranged on an opposite side to each of the ventilation holes <NUM> across the center axis CA of the cylindrical holding member <NUM>. Additionally, the plurality of ventilation holes <NUM> are preferably arranged at same positions to each other in a direction along the center axis CA of the cylindrical holding member <NUM>. However, the plurality of ventilation holes <NUM> may also be arranged to be displaced to each other in a direction along the center axis CA of the cylindrical holding member <NUM>.

The cooling layer <NUM> is a layer that cools flavor generated at the flavor source <NUM>. The cooling layer <NUM> is provided on an inner surface of the cylindrical holding member <NUM> to face the second flow path <NUM>. The cooling layer <NUM> preferably surrounds the second flow path <NUM>, in at least a part of section of the second flow path <NUM>. The cooling layer <NUM> is preferably provided only downstream of the flavor source <NUM>. The cooling layer <NUM> preferably has a thickness not to remarkably increase a fluid resistance of the second flow path <NUM>. Depending on a diameter of the second flow path <NUM>, the thickness of the cooling layer <NUM> is, for example, preferably <NUM> or more to <NUM> or less. Further, in a cross section vertical to the center axis CA of the cylindrical holding member <NUM>, a ratio of a cross-sectional area of the cooling layer <NUM> with respect to a cross-sectional area inside an inner wall of the cylindrical holding member <NUM> is preferably <NUM>% or more to <NUM>% or less, more preferably <NUM>% or more to <NUM>% or less. For example, in the cross section vertical to the center axis CA of the cylindrical holding member <NUM>, an outer diameter of the cylindrical holding member <NUM> may be <NUM> to <NUM>, the thickness of the cylindrical holding member <NUM> may be <NUM> to <NUM>, and the thickness of the cooling layer <NUM> may be <NUM> to <NUM>.

In the first embodiment, the cooling layer <NUM> is provided only downstream of the ventilation holes <NUM>. In other words, the cooling layer <NUM> does not reach the upstream side from the ventilation holes <NUM>. Alternatively, a part of the cooling layer <NUM> may reach the upstream side of the ventilation holes <NUM>. Namely, only at least a part of the cooling layer <NUM> needs to be provided downstream of the ventilation holes <NUM>.

The cooling layer <NUM> preferably has a length equal to or longer than a half length of the second flow path <NUM> in the extending direction of the second flow path <NUM>. The cooling layer <NUM> is preferably separated from the first thermal conductor <NUM> that composes the cylindrical holding member <NUM>.

The cooling layer <NUM> preferably defines a single channel to be passed with the flavor, in the cylindrical holding member <NUM>. More preferably, inside of the cooling layer <NUM> is hollow. Here, "inside of the cooling layer <NUM> is hollow" means that any member is not present inside the cooling layer <NUM>, other than a filter <NUM> provided to the suction port <NUM>. In this case, a volume of a cavity portion in the second flow path <NUM> can be larger. In this embodiment, the cooling layer <NUM> defines the single channel in the cylindrical holding member <NUM>, and inside of the cooling layer <NUM> is hollow.

In the first embodiment, inside of the cooling layer <NUM> is hollow. Alternatively, inside the cooling layer <NUM> may be provided with any member to an extent not to significantly increase a flow-path resistance of the second flow path <NUM>. For example, a cylindrical member may be provided along the center axis of the second flow path. This cylindrical member may also be provided with another cooling layer on its outer peripheral surface.

The cooling layer <NUM> may include a second thermal conductor. The second thermal conductor may be metal. As an example, the cooling layer <NUM> may be formed from a metal pipe. Alternatively, the cooling layer <NUM> may be formed from a metal-laminated paper including a paper, and a metal layer that is laminated to the paper. As the metal described above, for example, aluminum can be used. Further, instead of these, the cooling layer <NUM> may also be a layer including polylactic acid (PLA). Furthermore, the cooling layer <NUM> may be formed from a same material as that of the first thermal conductor <NUM> that composes the cylindrical holding member <NUM>.

The cooling layer <NUM> may have a plurality of projections and depressions for increasing a surface area of the cooling layer <NUM>. Such projections and depressions can be formed, for example, by crepe processing of a surface of the cooling layer <NUM>. These projections and depressions allow an increase in a heat-exchange-surface area of the cooling layer <NUM>, without making the cross-sectional area of the second flow path <NUM> too small.

According to one embodiment, a flavor inhaler <NUM> has a cooling layer <NUM> provided only downstream of a flavor source <NUM>, and the cooling layer <NUM> is provided on an inner surface of the cylindrical holding member <NUM> and facing a second flow path <NUM>. Since the cooling layer <NUM> facing the second flow path <NUM> is provided on the inner surface of the cylindrical holding member <NUM>, inside of the cylindrical holding member <NUM> does not need to be filled with a cooling element. If inside of the cylindrical holding member <NUM> is filled the cooling element, a ventilation resistance is increased, complicating a design of the ventilation resistance. In this embodiment, inside of the cylindrical holding member <NUM> does not need to be filled with the cooling element, achieving an easy design of the ventilation resistance.

According to one embodiment, a cylindrical holding member <NUM> has a ventilation hole <NUM> that allows external air to flow into a second flow path <NUM>, and at least a part of a cooling layer <NUM> is provided downstream of the ventilation hole <NUM>. Gas having passed the flavor source <NUM> is cooled by external air flowing in from the ventilation hole <NUM>, and is passed to the second flow path <NUM> to which the cooling layer <NUM> faces. This enables an increase in cooling efficiency of the gas flowing in the second flow path <NUM> passing through the flavor source <NUM>.

According to one embodiment, a ventilation hole <NUM> is formed such that external air flows into a second flow path <NUM> in a crossing direction to an extending direction of the second flow path <NUM>. It has been found that a cooling layer <NUM> and an inflow of external air from the ventilation hole <NUM> cause synergistic improvement of cooling effect. This may be because a gas flow flowing toward a non-ignition end E2 in the second flow path <NUM> (arrow F3 in <FIG>) is disturbed by external air flowing in from the ventilation hole <NUM> (arrow F4 in <FIG>) to cause a turbulent flow, allowing the gas flow having passed the flavor source to easily come into contact with the cooling layer <NUM>.

According to one embodiment, a ventilation hole <NUM> is provided on an opposite side to a suction port <NUM>, with respect to a center CL of a cylindrical holding member <NUM> in an extending direction of a second flow path <NUM>. Longer length of the second flow path <NUM> on a downstream side of the ventilation hole <NUM> allows increased cooling effect of gas having passed the flavor source <NUM>. Moreover, the ventilation hole <NUM> is relatively far away from the suction port <NUM>, preventing possibility that a user closes the ventilation hole <NUM> with a finger during a puff action.

According to one embodiment, a plurality of ventilation holes <NUM> are provided on a circumferential direction of a cylindrical holding member <NUM> at intervals. This enables uniform cooling of gas in a second flow path <NUM> in a circumferential direction of the second flow path <NUM>.

According to one embodiment, a cooling layer <NUM> is separated from a first thermal conductor <NUM>. This can prevent a direct flow of heat generated at a combustion heat source <NUM>, into the cooling layer <NUM>. This results in enabling prevention of a reduction in cooling effect of the cooling layer <NUM>. Moreover, the heat generated at the combustion heat source <NUM> is effectively transmitted to a flavor source <NUM>.

According to one embodiment, a ventilation hole <NUM> is provided between a first thermal conductor <NUM> and a cooling layer <NUM>. Namely, the ventilation hole <NUM> is provided where the first thermal conductor <NUM> or the cooling layer <NUM> is not present. This provides an advantage that the ventilation hole <NUM> can be easily formed to a cylindrical holding member <NUM>.

According to one embodiment, a cooling layer <NUM> is formed from a same material as that of a first thermal conductor <NUM>. This allows the first thermal conductor <NUM> and the cooling layer <NUM> to be formed in a same process, enabling easy production of a flavor inhaler <NUM>.

According to one embodiment, a cooling layer <NUM> defines a single channel to be passed with flavor. According to another embodiment, inside of a cooling layer <NUM> is hollow. This allows a ventilation resistance to be maintained relatively low, compared with an aspect in which inside of a cylindrical holding member <NUM> is filled with a cooling element curled so as to form a plurality of channels.

According to one embodiment, a cooling layer <NUM> has a length equal to or longer than a half length of a second flow path <NUM> in an extending direction of the second flow path <NUM>. Since the cooling layer <NUM> extends thus relatively long, cooling efficiency of gas in the second flow path <NUM> can be promoted.

A flavor inhaler 10A according to a second embodiment is described below with reference to <FIG>. The same reference numerals are given to the same configurations as those of the first embodiment. Differences from the first embodiment are mainly described below.

In the second embodiment, a cylindrical holding member <NUM> has a plurality of layers, at least at a section provided with a second flow path <NUM>. For example, the cylindrical holding member <NUM> may have an outer-wall portion <NUM>, and an inner-wall portion <NUM> provided inside the outer-wall portion. The inner-wall portion <NUM> may be formed from a sheet attached to an inner surface of the outer-wall portion <NUM>. Alternatively, the inner-wall portion <NUM> may also be formed from a pipe member inserted into the outer-wall portion <NUM>.

The cooling layer <NUM> is provided on an inner surface of the cylindrical holding member <NUM>, namely, on an inner surface of the inner-wall portion <NUM>. Thus, the cooling layer <NUM> may also be formed on the inner surface of the cylindrical holding member <NUM> that has a plurality of layers. In this case, from a viewpoint of a flow-path resistance, a thickness of the cylindrical holding member <NUM> and a thickness of the cooling layer <NUM> are preferably designed so as not to make a cross-sectional area of the second flow path <NUM> too small. The cross-sectional area of the second flow path <NUM> in a cross section vertical to a center axis CA of the cylindrical holding member <NUM> is preferably <NUM><NUM> or more to <NUM><NUM> or less, more preferably <NUM><NUM> or more to <NUM><NUM> or less. For example, in the cross section vertical to the center axis CA of the cylindrical holding member <NUM>, an outer diameter of the cylindrical holding member <NUM> may be <NUM> to <NUM>, the thickness of the cylindrical holding member <NUM> may be <NUM> to <NUM>, and the thickness of the cooling layer <NUM> may be <NUM> to <NUM>.

Claim 1:
A flavor inhaler (<NUM>) comprising:
a flavor source (<NUM>) configured to generate flavor without combusting;
a cylindrical holding member (<NUM>) including at least the flavor source (<NUM>) inside; and
a flow path (<NUM>, <NUM>) that is provided in the cylindrical holding member (<NUM>) and that is extending from the flavor source (<NUM>) toward a suction port (<NUM>) for sucking the flavor;
wherein the suction port (<NUM>) comprises a filter (<NUM>); and
wherein the cylindrical holding member (<NUM>) has one or more holes (<NUM>) arranged such that external air flows into the flow path (<NUM>, <NUM>) without passing the flavor source (<NUM>), characterized by a cooling layer (<NUM>) provided only downstream of the flavor source (<NUM>), wherein the cooling layer (<NUM>) is provided on an inner surface of the cylindrical holding member (<NUM>), and faces the flow path (<NUM>, <NUM>), and wherein inside of the cooling layer (<NUM>) is hollow.