COOLING ELEMENT

Abstract

The present invention provides a cooling element (4) with a longitudinally extending core of cellulose acetate material having a profiled outer surface including a plurality of grooves or channels (9) which extend the full length of the core for use with a smoking article such as a tobacco heated product (1) or heat-not-burn product (1).

Claims

1. A cooling element comprising a longitudinally extending core of cellulose acetate material; the longitudinally extending core of cellulose acetate material having a profiled outer surface including a plurality of grooves or channels of depth 0.5 to 2.6 mm which extend the full length of the core.

2. A cooling element according to claim 1 further comprising an outer wrapper engaged around the longitudinally extending core which defines with the profiled outer surface of the core a plurality of covered grooves or channels of depth 0.5 to 2.6 mm which extend the full length of the tubular core.

3. A cooling element comprising a longitudinally extending tubular core of cellulose acetate material; the longitudinally extending tubular core of cellulose acetate material having an inner surface which defines a bore extending longitudinally through the full length of the tubular core, and a profiled outer surface including a plurality of grooves or channels of depth 0.5 to 2.6 mm which extend the full length of the tubular core.

4. A cooling element according to claim 3 further comprising an outer wrapper engaged around the longitudinally extending tubular core which defines with the profiled outer surface of the core a plurality of covered grooves or channels of depth 0.5 to 2.6 mm which extend the full length of the tubular core.

5. A cooling element according claim 1 wherein the profiled outer surface defines 3 to 10, for example 3 to 7, for example 4 to 6, for example 5, channels of depth between 0.5 mm and 2.6 mm.

6. A cooling element according to claim 1 wherein the depth of each channel is from 0.5 to 2.5 mm, for example 0.8 to 2.2 mm, for example 1.30 to 2.1 mm, preferably from 1.35 to 2 mm, for example 1.4 to 1.9 mm.

7. A cooling element according to claim 1 wherein the length of the cooling element is from 5 to 35 mm, e.g. 10 to 2 5mm, e.g. 15 to 20 mm, e.g. 18 mm.

8. A cooling element according to claim 1 wherein the circumference of the cooling element is from 12 to 30 mm, e.g. 15 to 28 mm, more preferably 17 to 25 mm.

9. A cooling element according to claim 1 wherein the cooling element is thermoformed from cellulose acetate.

10. (canceled)

11. A cooling element for a tobacco heated product and/or HNB product comprising a longitudinally extending tubular core of cellulose acetate material; the longitudinally extending tubular core of cellulose acetate material having an inner surface which defines a bore extending longitudinally through the full length of the tubular core, and a profiled outer surface including a plurality of grooves or channels which extend the full length of the tubular core.

12. A cooling element for a tobacco heated product and/or HNB product comprising a longitudinally extending core of cellulose acetate material; the longitudinally extending core of cellulose acetate material having a profiled outer surface including a plurality of grooves or channels which extend the full length of the tubular core.

13. A smoking article (e.g. Tobacco heating product, HNB product) comprising a cooling element according to claim 1.

14. A smoking article comprising: a hollow tubular element, the hollow tubular element having bore of diameter A; and, abutted thereto, a cooling element comprising a longitudinally extending tubular core of cellulose acetate material; the longitudinally extending tubular core of cellulose acetate material having an inner surface which defines a bore extending longitudinally through the full length of the tubular core, and a profiled outer surface including a plurality of grooves or channels of depth 0.5 to 2.6 mm which extend the full length of the tubular core; wherein diameter A is sufficiently large such that a part of the bore of the hollow tubular element is in register with a part of the bore of the cooling element, and a part of the bore of the tubular element is in register with at least a part of a (or preferably each) groove (channel).

15. A smoking article comprising: a hollow tubular element, the hollow tubular element having bore of diameter A; and, abutted thereto, a cooling element comprising a longitudinally extending core of cellulose acetate material; the longitudinally extending core of cellulose acetate material having a profiled outer surface including a plurality of grooves or channels of depth 0.5 to 2.6 mm which extend the full length of the core; wherein diameter A is sufficiently large such that a part of the bore of the tubular element is in register with at least a part of a (or preferably each) groove (channel).

16. A smoking article according to claim 14 where the hollow tubular element is formed from cellulose acetate.

17. A smoking article according to claim 14 where the hollow tubular element has walls of thickness 0.3 mm to 5.5 mm, for example 0.4 mm to 5.5 mm, for example 0.4 to 1.0 mm or 1.0 to 5.5 mm.

18-20. (canceled)

Description

[0040] The present invention will now be discussed in further detail with reference to the attached FIG. 1 which shows (not to scale) a longitudinal cross section of a tobacco heated product according to the invention which includes a cooling element according to the invention;

[0041] FIG. 2 which shows (not to scale) an axial cross section (along line X-X of FIG. 1) of the cooling element of the invention shown in FIG. 1;

[0042] FIG. 3 which shows (not to scale) an axial cross section (along line X-X of FIG. 1) of a different cooling element to that of FIG. 2, which is also of the invention, which could be used in the tobacco heated product according to the invention shown in FIG. 1; and

[0043] FIG. 4 which compares pressure drop (mmWG) of cooling elements of the invention (B, C, D, E) with a conventional PLA cooling element (A).

[0044] FIG. 1 shows a longitudinal cross section along the centre line of a cylindrical HNB product 1. Cylindrical HNB product 1 comprises four segments: a cylindrical plug of reconstituted tobacco 2; a cylindrical hollow acetate tube 3; a cooling element 4; and a cylindrical plug of cellulose acetate tow 5.

[0045] Plug 2 of reconstituted tobacco 2 is 12 mm long and has circumference 23.2 mm, and forms one end of the HNB product 1. Such plugs are well known in the art. This plug is heated in use by a heating device as is well known in the art. The plug 2 of reconstituted tobacco material is abutted at one end to a 7 mm long cylindrical hollow acetate tube 3, also of circumference 23.2 mm, and wall thickness 1.3 mm. Tube 3 has a cylindrical bore 3a. The end of the cylindrical hollow acetate tube 3 opposite to plug 2 is abutted to cooling element 4. Hollow acetate tubes and their manufacture are well known in the art of tobacco smoke filters (see e.g. GB970817, e.g. FIG. 7 embodiment and associated discussion).

[0046] Cooling element 4 comprises a longitudinally extending tubular core of thermoformed cellulose acetate material of length 18 mm. The longitudinally extending tubular core of cellulose acetate material is thermoformed with an inner surface which defines a bore (or hole) 8 of diameter 2 mm extending longitudinally through the full length of the tubular core, and a profiled outer surface including five longitudinally extending channels or grooves 9 of generally shallow U-shaped cross section with maximum depth 1.80 mm and width 1.5 mm which extend the full length of the tubular core. The five channels 9 are spaced equidistantly around the perimeter of the profiled outer surface (as can be seen from FIG. 2). The longitudinally extending tubular core of cellulose acetate material is of uniform axial cross section, as shown in FIG. 2. It will be appreciated that the cross section of the cooling element 4 can be considered to be generally annular with five shallow U-shaped grooves or channels 9 disposed equidistantly about its perimeter. The term “circumference”, when used with reference to the grooved/channeled cooling element, refers to an imaginary circular line which runs around the outer (circular) part of the cooling element but ignores the channels; thus the circumference of element is approximately 23.2 mm such that it is generally in register with the outer surface of the hollow acetate tube 3 (which has similar circumference) to which it abuts. Cooling element 4 is thermoformed using a steam bonded process, as is well known in the art. Cellulose acetate tow is processed and then fed into a steam die which has a lead in but tapers down to the size and shape of cross section that is required (e.g. the cross section shown in FIG. 2). As the tow passes through the die it is formed and partially cured to form the shape required. There may be more than one steam die which may be followed by a number of drying stations which blow hot air onto the rod to rid it of any excess steam/moisture. The rod is then fed onto a garniture where it is pulled through and cut to the desired length.

[0047] Cylindrical plug 5 is of length 8 mm and circumference 23.2 mm and comprises a rod of cellulose acetate tow with plug wrap disposed there around. Such “wrapped acetate” plugs are well known in the art of tobacco smoke filters. Plug 5 is abutted to the opposite end of cooling element 4 to hollow acetate tube 3 such that cooling element 4 is between plug 5 and hollow acetate tube 3.

[0048] The cylindrical plug of reconstituted tobacco 2, cylindrical hollow acetate tube 3, cooling element 4, and a cylindrical plug of cellulose acetate tow 5 are further wrapped with a plug wrap (not shown) of conventional plugwrap paper (that is well known in the art) which surrounds the plug 2, tube 3, element 4 and plug 5 and which provides an external appearance similar to a cigarette.

[0049] The diameter of bore 3a (which may be referred to herein as dimension “A”) is sufficiently large such that a part of the bore 3a of the tubular element 3 is in register with (e.g. a part of) the bore 8 of the cooling element, and a part of the bore of the tubular element is in register with at least a part (i.e. the lowest extremities) of each groove (channel) 9. It will be therefore be appreciated that the external grooves or channels 9 of the cooling element 4, as well as the central bore 8, partially overlap with the wider bore 3a of the hollow acetate tube 3. During use, hot vapour from the plug of tobacco (which is heated in the conventional manner) is drawn through the bore 3a of the hollow acetate tube 3 and into the bore 8 and channels 9 of the cooling element 4, and then on into and through the final acetate plug 5 to the smoker's mouth. It is believed that this drawing of the hot vapour through both the bore 8 and channels 9 of the cooling element 4 provides adequate cooling, an effect which is not expected from cellulose acetate material.

[0050] It will be appreciated that the hollow acetate tube, wrapped acetate segment, and cooling element may be made by methods well known in the art.

[0051] FIG. 3 shows (not to scale) an axial cross section (along line X-X of FIG. 1) of a different cooling element 40′, also of the invention, which could be used in the tobacco heated product according to the invention shown in FIG. 1. It will be appreciated that heating element 40′ may be used in place of element 4 in the tobacco heated product according to the invention shown in FIG. 1.

[0052] Cooling element 40′ comprises a longitudinally extending core of thermoformed cellulose acetate material of length 18 mm. The longitudinally extending core of cellulose acetate material is thermoformed with a profiled outer surface including five longitudinally extending channels or grooves 90′ of generally shallow U-shaped cross section with maximum depth 1.80 mm and width 1.5 mm which extend the full length of the core. The five channels 90′ are spaced equidistantly around the perimeter of the profiled outer surface (as can be seen from FIG. 3). The longitudinally extending core of cellulose acetate material is of uniform axial cross section, as shown in FIG. 3. It will be appreciated that the cross section of the cooling element 40′ can be considered to be generally circular with five shallow U-shaped grooves or channels 90′ disposed equidistantly about its perimeter. The term “circumference”, when used with reference to the grooved/channeled cooling element, refers to an imaginary circular line which runs around the outer (circular) part of the cooling element but ignores the channels; thus the circumference of element 40′ is approximately 23.2 mm such that it is generally in register with the outer surface of the hollow acetate tube 3 shown in FIG. 1 (which has similar circumference) to which it abuts if cooling element 40′ is used in place of cooling element 4 in FIG. 1. Cooling element 40′ is thermoformed using a steam bonded process, as is well known in the art. Cellulose acetate tow is processed and then fed into a steam die which has a lead in but tapers down to the size and shape of cross section that is required (e.g. the cross section shown in FIG. 3). As the tow passes through the die it is formed and partially cured to form the shape required. There may be more than one steam die which may be followed by a number of drying stations which blow hot air onto the rod to rid it of any excess steam/moisture. The rod is then fed onto a garniture where it is pulled through and cut to the desired length.

[0053] If the cooling element of FIG. 3 is used in the product of claim 1, it will be appreciated that the diameter of bore 3a (which may be referred to herein as dimension “A”) is sufficiently large such that a part of the bore of the tubular element is in register with at least a part (i.e. the lowest extremities) of each groove (channel) 90′. It will be therefore be appreciated that the external grooves or channels 90′ of the cooling element 40′ partially overlap with the bore 3a of the hollow acetate tube 3. During use, hot vapour from the plug of tobacco (which is heated in the conventional manner) is drawn through the bore 3a of the hollow acetate tube 3 and into the channels 90′ of the cooling element 40′, and then on into and through the final acetate plug 5 to the smoker's mouth. The cooling element 40′ provides adequate cooling, an effect which is not expected from cellulose acetate material.

EXPERIMENT

[0054] Cooling elements of the invention (B, C, D, E) were made. Cooling elements B and C have similar cross section to that shown in FIG. 3, with no central hole or bore. Cooling elements B and C thus have generally circular cross section of circumference 22.30 mm and 5 channels of depth 1.2 mm. Cooling elements D and E are as shown in FIG. 2, including a central bore. Cooling elements D and E also have generally circular cross section of circumference 22.30 mm and 5 channels of depth 1.2 mm, but include a central bore of diameter 1.2 mm. Cooling elements B, C, D and E were tested against a conventional PLA cooling element (A) in a HNB product.

[0055] Five HNB products as shown in FIG. 1 were assembled for testing, each including one of cooling elements of the invention B, C, D E or comparative example A (known PLA product). Cooling elements A, C and E were used with a hollow acetate tube (element 3 in FIG. 1) of circumference 22.30 mm and wall thickness 1.3 mm. Cooling elements B and D were used with a “thin walled tube (TWT)” hollow acetate tube (element 3 in FIG. 1) of circumference 22.30 mm and wall thickness 0.8 mm.

[0056] FIG. 4 compares pressure drop (mmWG) associated with cooling elements of the invention (B, C, D, E) and conventional PLA cooling element (A). This shows that the profiles are similar, indicating that the cooling elements of the invention are an excellent heat sink in a THP product and are suitable as a replacement for PLA. The cooling elements of the invention may therefore provide a biodegradable alternative to the known PLA cooling elements. It can be seen that B and C (no central bore) are closer in performance to PLA, indicating they perform better than D and E in this test.