Smoke-free cigarette

Abstract

The present invention relates to a smoke-free cigarette with a thermal unit for the autarkical generation of heat and a nicotine reservoir in which nicotine or a nicotine-containing compound is contained, wherein the thermal unit comprises a crystallizable medium which releases heat during its crystallization.

Claims

1. A method for manufacturing a smoke-free cigarette, comprising the following steps: providing a thermal unit, heating crystallizable medium to a temperature of at least 50 C. at which the crystallizable medium at least partly goes into solution, before being filled into the thermal unit, then filling the thermal unit with the solution, providing a nicotine reservoir, providing a mouthpiece, and arranging the mouthpiece, the nicotine reservoir and the thermal unit in a common outer envelope comprising three layers in the following order, an outermost layer including paper and having optical properties of a conventional cigarette, an intermediate layer being a desorption barrier including metal and configured to prevent or restrict desorption of nicotine and/or flavoring agents, and an innermost layer stabilizing layer including plastic and configured to provide the cigarette with mechanical stability.

2. The method according to claim 1, wherein the crystallizable medium is a salt hydrate and is heated to a temperature at which the salt at least partly goes into solution in its own crystal water.

3. The method according to claim 1, wherein the medium contains hydrate and water and filling is performed under a water vapor pressure which lies above a desorption pressure of the water of the medium.

4. The method according to claim 1, comprising surrounding the thermal unit with the nicotine reservoir.

5. The method according to claim 1, wherein the thermal unit is autarkical.

6. The method according to claim 1, wherein the crystallizable medium has a temperature of at least 60 C.

7. The method according to claim 1, wherein the thermal unit is filled with the crystallizable medium through one or more cannulas from a storage container in which the crystallizable medium is heated.

8. A method for manufacturing a smoke-free cigarette, comprising the following steps: providing a thermal unit, surrounding the thermal unit with a nicotine reservoir, providing a mouthpiece, and arranging the mouthpiece, the nicotine reservoir and the thermal unit in a common outer envelope comprising three layers in the following order, an outermost layer including paper and having optical properties of a conventional cigarette, an intermediate layer being a desorption barrier including metal and configured to prevent or restrict desorption of nicotine and/or flavoring agents, and an innermost layer stabilizing layer including plastic and configured to provide the cigarette with mechanical stability.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details and advantages of the invention will be explained in detail with reference to an embodiment illustrated in the drawing.

(2) FIG. 1: shows a smoke-free cigarette in accordance with the present invention in a longitudinal section in a first embodiment,

(3) FIG. 2: shows an enlarged segment of the trigger mechanism shown in FIG. 1,

(4) FIG. 3: shows a smoke-free cigarette in accordance with the present invention in a longitudinal section in a second embodiment,

(5) FIG. 4: shows a smoke-free cigarette in accordance with the present invention in a longitudinal section in a third embodiment,

(6) FIG. 5: shows a smoke-free cigarette in accordance with the present invention in a longitudinal section in a fourth embodiment,

(7) FIG. 6: shows a sectional view through a three-layer outer envelope of a smoke-free cigarette in accordance with the invention, and

(8) FIG. 7: shows a schematic drawing of a filling operation of a thermal unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) The smoke-free cigarette in accordance with the present invention should supply nicotine, but rather not noxious and carcinogenic substances to the smoker. The smoke-free cigarette 10 comprises an autarkical thermal unit 14 or 40, a nicotine-containing substrate 15 or 50 and a mouthpiece 20.

(10) The smoke-free cigarette 10 in accordance with the present invention functions without supply of heat or energy from outside and thus is autarkical. The smoke-free cigarette of the present invention is configured such that it is immediately ready for operation, if this is desired by the user. In particular, it is a disposable cigarette, which can be used only once and is then thrown away.

(11) In the interior of the thermal unit a liquid to be crystallized is contained, which is able to release heat during the crystallization. The crystallization process is started by actuation of a trigger mechanism, wherein the entire unit is heated to about 45 to 55 C. and continuously releases heat for about 5 to 10 minutes. These values are exemplary values. The temperature and the time period during which heat is released can for example be adjusted via the amount of salt to be crystallized.

(12) Advantageously, the thermal unit is dimensioned such that the same releases heat for at least one minute, preferably for a period in the range from 2 to 4 minutes.

(13) When the user pulls air through the mouthpiece 20, the stream of air is guided through the tobacco 15, 50 and thereby heated over the effective length due to the heat generated by the thermal unit 14, 40. The air stream absorbs the evaporating nicotine along with flavoring agents and is passed through the mouthpiece 20, which can also serve as filter. The mouthpiece 20 limits the air stream and is dimensioned such that maximum nicotine limit values are not reached or exceeded.

(14) The smoke-free cigarette 10 in accordance with the present invention functions without supply of heat or energy from outside and thus is autarkical. After activation of the thermal unit the crystallization of the supersaturated, metastable solution begins. For example, it can be a solution of sodium acetate trihydrate (CH.sub.3COONa 3 H.sub.2O) in liquid. The crystallization heat released during the exothermal reaction is released in several steps.

(15) After activation, the sodium acetate trihydrate spontaneously crystallizes out and releases the heat stored in the unit in the form of latent heat (CH.sub.3COO.sup.(aq.)+Na.sup.+ (aq.).fwdarw.CH.sub.3COONa 3 H.sub.2O (solid) plus heat), wherein the ions present in the unit initially form the ionic lattice.

(16) Simultaneously with this process, the water molecules take the places defined in the interstices of the ionic lattice formed in this way, with their dipoles being aligned exactly. In this way, the water molecules form a lattice in the crystal lattice.

(17) In the case of the sodium acetate trihydrate three water molecules are arranged per formula unit.

(18) The heat released during crystallization thus on the one hand consists of the latent heat of the salt, i.e. of its heat of solution or heat of crystallization. On the other hand, heat is produced during the strongly exothermal formation of the lattice of water molecules, which takes place in parallel thereto. This heat of formation of the hydrate likewise is a latent heat.

(19) Alternatively or in addition to the use of sodium acetate trihydrate, sodium sulfate or the so-called Glauber's salt, i.e. the decahydrate (Na.sub.2SO.sub.4 10 H.sub.2O) can be used. Alternatively or in addition, the use of magnesium nitrate hexahydrate (Mg(NO.sub.3).sub.2 6 H.sub.2O) as such or in a mixture with lithium nitrate (LiNO.sub.3) can also be considered.

(20) The mouthpiece 20 ensures a constant draft of air inside the cigarette.

(21) FIG. 1 shows a first embodiment of the present invention. The cigarette 10 includes an outer envelope 22, which can have a design as it corresponds to a conventional cigarette. The outer envelope 22 and hence the outer shape of the cigarette 10 preferably is cylindrical. The outer envelope can be constructed as it will yet be shown in detail with reference to FIG. 6.

(22) At its end facing the user, the cigarette 10 includes a filter 20, by means of which the air volume to be inhaled per unit time can be limited or be maintained at a constant value.

(23) Adjacent to the filter 20 a tobacco piece 30 is provided, in which the end region of a thermal unit 40 facing the user is arranged. The thermal unit 40 is located in the interior of the cigarette 10 and in peripheral direction is completely surrounded by tobacco 50 which is enriched with nicotine. This tobacco filling 50 is disposed in the annular space which surrounds the thermal unit 40.

(24) Adjacent to this tobacco substrate 50 enriched with nicotine a further tobacco piece 60 is provided, which forms the end of the cigarette 10 facing away from the user.

(25) The smoke-free cigarette 10 furthermore comprises a sheath surrounding the thermal unit 40 on its outside, which consists e.g. of a plastic film.

(26) The trigger mechanism of the first embodiment, which is shown again in detail in FIG. 2, will now be described. In the region of the thermal unit 40 facing away from the user one or more resilient guides 70 are fixed to the same.

(27) The spring 70 has an inclined portion which extends at an acute angle with respect to the longitudinal axis of the thermal unit 40, and an adjoining portion which extends parallel to the longitudinal axis of the thermal unit 40 or of the cigarette 10.

(28) In one region, the springs 70 are surrounded by a fixing ring 80 which is deformable.

(29) On the fixing ring 80 or on the spring(s) 70, one or more injection pins 90 are arranged, which extend vertical to the thermal unit 40.

(30) If the injection pin(s) 90 is(are) arranged on the spring 70, this preferably is the case in the region in which the spring 70 extends parallel to the longitudinal axis of the thermal unit 40.

(31) While the spring 70 exerts a force directed away from the thermal unit 40, it can be provided that the fixing ring 80 has the function to position the springs 70 and hence the injection pins 90 such that in the non-actuated condition they sit on the surface of the thermal unit 40 or only have a small distance from the same, but only penetrate into the same when a compressive force acts on the fixing ring 80 or on the injection pins 90 from outside.

(32) As can be taken from FIG. 2, the injection pins 90 have a pointed end with which they penetrate into the thermal unit 40 upon actuation of the trigger mechanism.

(33) Due to the penetration of the injection pin(s) 90, a change of stage, in particular a crystallization, can be initiated, in which heat is released. It is conceivable that the change of state is caused by the penetration of the injection pin 90 into the thermal unit 40 or that the injection pin 90 for example includes means which promote the change of stage, such as crystallization nuclei.

(34) The configuration of the cigarette in accordance with the invention includes a comparatively simply constructed and easily actuated trigger mechanism. In addition, the same can be fabricated such that it is small sized, so that miniaturization is possible.

(35) FIG. 3 now shows a second embodiment which differs from the first embodiment in the arrangement of nicotine reservoir and thermal unit and in the trigger mechanism. The medium used in the thermal unit is configured exactly as described above.

(36) In the second embodiment, conventional tobacco which is slightly enriched with nicotine is disposed in a cylindrical inner space 15, which is surrounded by the hollow cylindrically arranged or configured thermal unit 14. The mouthpiece 20 provides a constant draft of air within the system. Via a trigger mechanism not shown in detail in FIG. 3, the crystallization is started and thereby the process of releasing heat is initiated. The initiation of the crystallization process is effected e.g. by a metal clip protruding into the solution, which is actuated mechanically and by which the crystallization is started and accelerated.

(37) The smoke-free cigarette 10 furthermore comprises a sheath 12 surrounding the thermal unit 14 on its outside. The same consists of a doubly sheathed plastic film, in whose interior the crystalline liquid or the liquid to be crystallized is contained, which is able to store heat. In accordance with the embodiment shown in the drawing, the sheath 12 only surrounds the thermal unit, but not the mouthpiece as well. In principle, however, it is also conceivable to provide the sheath 12 also over the entire length of the smoke-free cigarette and hence also over the mouthpiece 20.

(38) The sheath 12 of the cigarette on the one hand serves to prevent the direct contact with the heat source in the form of the thermal unit 14 and/or is designed such that it optically resembles a conventional cigarette. The sheath 12 can be configured such as it will yet be shown below with reference to FIG. 6.

(39) In contrast to the embodiment as shown in FIG. 3, it is provided in accordance with FIG. 4 that the end of the cigarette 10 spaced from the mouthpiece 20 is closed by a capping 25. Prior to use, the user separates or tears off the cap 25 from the cigarette 10, which results in the fact that air can be sucked through the cigarette 10 or through the nicotine-containing substrate 15.

(40) Apart from the embodiments shown in FIGS. 1 to 4 it is also conceivable to change the arrangement of the thermal unit and of the nicotine-containing substrate. It is conceivable, for example, to arrange the thermal unit and the nicotine-containing substrate one behind the other in longitudinal direction of the cigarette. It is conceivable, for example, to arrange the thermal unit at the end of the cigarette spaced from the mouthpiece 20 and the nicotine-containing substrate between thermal unit and mouthpiece.

(41) Such configuration of the cigarette can be taken from FIG. 5. Between thermal unit 14 and mouthpiece 20 the nicotine-containing substrate 15 is disposed. In the embodiment of FIG. 5, the thermal unit 14 also is closed by the cap 25 which prevents the access of air to the substrate 15, until it is removed by the user.

(42) FIG. 5 furthermore shows that the thermal unit 14 is interspersed with air ducts 16. The same extend in longitudinal direction of the cigarette 10. The feature that one or more air ducts 16 are arranged in the thermal unit 14, in order to improve or just provide for the air supply, is not limited to the embodiment as shown in FIG. 5, but is an aspect of the present invention which is possible in principle.

(43) It is conceivable to make the sheath of the cigarette air-tight. It is also conceivable, however, to make the sheath air-permeable, which results in that oxygen also (or exclusively) penetrates into the thermal unit 14 or into the substrate 15 via the sheath surface. To prevent that this happens before it is desired by the user, it can be provided to enclose the sheath with a preferably air-tight envelope which can be removed by the user.

(44) FIG. 6 shows a longitudinal section through an embodiment of a three-layer outer envelope of a smoke-free cigarette. In particular, such outer envelope can be used in one of the aforementioned embodiments.

(45) As shown, the outer envelope consists of three material layers. The outer paper layer 1 serves the configuration of haptic, optical and tactile properties of a conventional cigarette.

(46) This paper layer 1 inwardly is adjoined by an aluminum layer 2, which forms the desorption barrier for nicotine and flavoring agents/flavors present in the space surrounded by the outer envelope.

(47) During the phase of use of the smoke-free cigarette, i.e. during the generation of heat by the autarkical thermal unit, the aluminum layer also serves for heat regulation.

(48) The aluminum layer 2 inwardly is adjoined by a plastic layer 3. The same consists of a plastic sheet and on the one hand provides the necessary total stability of the smoke-free cigarette, puff regulation and flavor stability.

(49) As can be taken from FIG. 6, three layers can thus be provided, in order to form the entire outer envelope.

(50) It is, however, also comprised by the invention that between two or all of the layers shown intermediate layers are provided, which have certain functional properties, such as improvement of the adhesion of the layers to each other, etc.

(51) Preferably, however, the outer envelope only consists of the three layers shown. An essential advantage of the illustrated arrangement consists in that a smokeless cigarette is provided, which can be stored over an extended period, since the desorption of nicotine or flavoring agents is largely impeded or completely prevented, without having to omit the familiar haptics of conventional cigarettes.

(52) The paper layer can form the outermost layer of the multilayer outer envelope. In principle, however, it is also comprised by the invention that a further layer, such as a coating or the like, is applied onto this layer. Similarly, the inner layer, i.e. the plastic layer 3 can form the innermost layer of the multilayer outer envelope. However, it is also comprised by the invention that a further layer, such as an inner coating, adjoins the inner layer.

(53) In the drawing, the three layers 1, 2, 3 of the outer envelope are shown with an identical or largely identical thickness. However, the invention also comprises the case that different thicknesses can be provided. For example, it can be sufficient to provide the desorption barrier in the form of a comparatively thin aluminum foil, which can represent the thinnest layer of the three illustrated layers.

(54) The outer envelope shown in FIG. 6 in a longitudinal section has the shape of a hollow cylindrical body in whose interior a matrix is disposed, on which nicotine and flavoring agents are provided. In the interior, the autarkical thermal unit furthermore is provided in the form of a crystallizable medium. This autarkical thermal unit can be activated for example by the user applying pressure from outside on the illustrated outer envelope. This results in crystallization and hence in the release of heat. On the one hand, a draft of air which is drawn through the interior of the smoke-free cigarette and possibly a mouthpiece is heated by this release of heat. Heating furthermore leads to the fact that the desorption of nicotine and/or flavoring agents from said matrix is facilitated.

(55) The manufacture of a thermal unit will now be described in detail. For filling the thermal unit with a supersaturated metastable solution the salt initially is heated. First of all, the crystal water lattice collapses. At the same time, the ionic lattice also is destroyed. This process takes place when heating the salt to a temperature of about 58 C.

(56) This process is a process of dissolution.

(57) In the case of the sodium acetate trihydrate this process takes place at a temperature of about 58 C. Initially, anhydrous sodium acetate is obtained. If heating is continued, the sodium acetate obtained is at least partly dissolved in its own crystal water. Corresponding processes take place when using Glauber's salt, i.e. the sodium sulfate decahydrate, and also when using magnesium nitrate hexahydrate, which can be present in a combination with lithium nitrate.

(58) A method for manufacturing a thermal unit will now be described in detail with reference to FIG. 7. In a schematic view, FIG. 7 shows the thermal pad tube 100, which upon filling with a crystallizable medium is closed and then used as an autarkical thermal unit of a smoke-free cigarette.

(59) As shown in the Figure, the thermal pad tube, which can have a maximum diameter of 6 mm and a maximum total length of 100 mm, is filled by means of a filling cannula 120 which in turn is connected with a storage container 130. The storage container 130 is connected with a non-illustrated filling hydraulic which has the function to fill the crystallizable medium through the filling cannula 120 into the interior of the thermal pad tube 100.

(60) As is illustrated by the double arrow in the Figure, the storage container 130 or the filling cannula 120 can be moved relative to the thermal pad tube 100 in axial direction thereof, so that for example first the left portion of the tube 100 as shown in the Figure and subsequently the regions adjoining thereto in the direction of the opening of the thermal pad tube 100 are filled.

(61) In the embodiment shown here in detail, sodium acetate in the liquid condition ready for use should be processed and filled in.

(62) Into the prefabricated, unilaterally closed thermal pad tubes 100, the sodium acetate is introduced by means of one or more cannulas 120, and subsequently the tubes 100 are closed. As explained above, to prevent the unintended spontaneous crystallization and the unintended doping with crystallization nuclei, the sodium acetate is maintained and processed at a temperature of more than 60 C. in the storage container 130 and possibly in addition also in the filling cannula 120. This procedure prevents both the spontaneous crystallization and the doping with crystallization nuclei.

(63) To prevent a change in the water content of the sodium acetate solution, the water vapor pressure of the salt hydrate solution in the storage container 130 or in the filling cannula 120 is adjusted to a value higher than the desorption pressure of the water in the salt hydrate solution.

(64) In principle, it is possible to adjust the temperature conditions described above and the water vapor pressure in the storage container 130 and/or in the filling cannula 120 and/or in the thermal pad tube 100 itself. In this way, it is reliably prevented that an undesired, premature crystallization occurs.

(65) The sodium acetate thermal pad in accordance with the embodiment described here is immediately ready for use upon filling. Due to the filling operation described above, the further processing of the thermal pad or of the thermal pad tubes 100 is unproblematic, and they or the smoke-free cigarettes provided therewith for example can also be stored over an extended period without the occurrence of an unintended crystallization of the sodium acetate.

(66) The present invention not only relates to cigarettes in the actual sense, but also to cigars. Thus, the term cigarette stands both for cigarettes and for cigars.