Abstract
There is disclosed a mouth piece, filter element or cooling element for an aerosol generating article comprising: a first section comprising a longitudinally extending core of filtering material having an outer surface and an inner surface, the inner surface defining a channel extending longitudinally from an end of the first section; a second section comprising a longitudinally extending core of filtering material; wherein the first section and the second section are adjacent and integral; wherein the channel has a non-circular transverse cross section which varies in the longitudinal direction by rotating about a longitudinal axis of the first section.
Claims
1. A mouth piece, filter element or cooling element for an aerosol generating article comprising: a first section comprising a longitudinally extending core of filtering material having an outer surface and an inner surface, the inner surface defining a channel extending longitudinally from an end of the first section; a second section comprising a longitudinally extending core of filtering material; wherein the first section and the second section are adjacent and integral; wherein the channel has a non-circular transverse cross section which varies in the longitudinal direction by rotating about a longitudinal axis of the first section.
2. The mouth piece, filter element or cooling element according to claim 1, wherein the channel has a transverse cross section which is a modified circle having one or more protuberant portions extending towards the centre of the circle, a cross shape, or a rectangle; and/or wherein the inner surface comprises one or more ridges which extend helically about a longitudinal axis of the first section.
3. (canceled)
4. The mouth piece, filter element or cooling element according to claim 1, comprising a third section comprising a longitudinally extending core of filtering material having an outer surface and an inner surface, the inner surface defining a channel extending longitudinally from an end of the third section; for example wherein the third section channel has a non-circular transverse cross section which varies in the longitudinal direction by rotating about a longitudinal axis of the third section; for example wherein the third section channel has a transverse cross section which is a modified circle having one or more protuberant portions extending towards the centre of the circle, a cross shape, or a rectangle.
5-6. (canceled)
7. A mouth piece, filter element or cooling element for an aerosol generating article comprising: a first section comprising a longitudinally extending core of filtering material having an outer surface and an inner surface, the inner surface defining a channel extending longitudinally from an end of the first section; a second section comprising a longitudinally extending core of filtering material; wherein the inner surface comprises one or more ridge(s) which extend helically about a longitudinal axis of the first section; and wherein the first section and the second section are adjacent and integral.
8. The mouth piece, filter element or cooling element according to claim 7 comprising: a third section comprising a longitudinally extending core of filtering material having an outer surface and an inner surface, the inner surface defining a channel extending longitudinally from an end of the third section; for example, wherein the inner surface comprises one or more ridge(s) which extend helically about a longitudinal axis of the third section.
9. (canceled)
10. The mouth piece, filter element or cooling element according to claim 4, wherein the third section is adjacent to the second section and integral with the second section, such that the second section is between the first section and the third section.
11. The mouth piece, filter element or cooling element according to of claim 2, wherein the or each ridge extends along the entire length of the inner surface; and/or wherein the inner surface comprises two or more ridges.
12. (canceled)
13. The mouth piece filter element or cooling element according to claim 1, wherein the filtering material comprises a plasticiser.
14. A filter for an aerosol-generating article comprising a filter element according to claim 1.
15. A multiple rod comprising a plurality of mouthpieces, filter elements or cooling elements according to claim 1 joined end-to-end in a mirror image relationship.
16. An aerosol-generating article comprising a mouthpiece, filter element or cooling element according to claim 1 or a filter for an aerosol-generating article comprising the filter element.
17. (canceled)
18. An apparatus for making a mouth piece filter element or cooling element for an aerosol generating article, the apparatus comprising: a shaping chamber having an inlet for receiving filtering material and an outlet for discharging a rod of filtering material; and a shaping rod; wherein the shaping rod is configured to rotate; wherein the shaping chamber comprises a curing zone extending longitudinally along at least part of the length of the shaping chamber; and wherein the shaping rod is configured to move longitudinally between a first position in which the end of the shaping rod is positioned at an end of the curing zone and the shaping rod extends along the entire length of the curing zone; and a second position in which the end of the shaping rod is distanced longitudinally from the first position and the shaping rod does not extend along the entire length of the curing zone.
19. The apparatus according to claim 18, wherein the shaping rod is coupled to a first motor for rotating the shaping rod; and/or wherein the shaping rod is coupled to a second motor for moving the shaping rod between the first and second position; and/or wherein the shaping chamber comprises a hollow substantially cylindrical element for shaping the filtering material; and/or wherein the shaping rod has a non-circular transverse cross section; for example wherein the non-circular transverse cross section is a modified circle having one or more indentations, a cross shape or a rectangle.
20-23. (canceled)
24. The apparatus according to claim 18, comprising a heating element for applying heat to the filtering material; and/or comprising a steam element for applying steam to the filtering material; for example wherein the shaping chamber comprises a steam element for applying steam to the filtering material within the curing zone.
25-26. (canceled)
27. The apparatus according to claim 18, comprising a cutting element for cutting the rod of filtering material; and/or comprising a plasticising element for applying plasticiser to the filtering material before the filtering material enters the shaping chamber.
28. (canceled)
29. A method of making a mouth piece, filter element or cooling element for an aerosol generating article, the method comprising: advancing filtering material in a longitudinal direction; drawing the filtering material into and through a shaping chamber, wherein the shaping chamber comprises an inlet for receiving filtering material and an outlet through which a rod of filtering material exits the shaping chamber; wherein the shaping chamber comprises a curing zone extending longitudinally along at least part of the length of the chamber; moving a shaping rod longitudinally between a first position in which the end of the shaping rod is positioned at an end of the curing zone and the shaping rod extends along the entire length of the curing zone, and a second position in which the end of the shaping rod is distanced longitudinally from the first position, and the shaping rod does not extend along the entire length of the curing zone; rotating the shaping rod; such that in the first position the advancing filtering material advances through the space defined by the inner surface of the chamber and the shaping rod to form a first section comprising a longitudinally extending core of filtering material having an outer surface and an inner surface, the inner surface defining a longitudinally extending channel having a non-circular transverse cross section which varies in the longitudinal direction by rotating about a longitudinal axis of the first section, and in the second position filtering material advances into the space defined by the end of the shaping rod, the inner surface of the chamber and the end of the curing zone to form a second section comprising a longitudinally extending core of filtering material; to thereby form a longitudinally extending rod of filtering material having alternating first and second sections.
30. The method according to claim 29, wherein heat is applied to the filtering material within the curing zone; and/or wherein steam is applied to the filtering material within the curing zone; and/or wherein the shaping chamber comprises a substantially cylindrical hollow element comprising an inlet for receiving filtering material and an outlet for discharging a rod of filtering material; and/or wherein shaping rod has a non-circular transverse cross section; for example wherein the non-circular transverse cross section is a modified circle having one or more indentations, a cross shape or a rectangle.
31-34. (canceled)
35. The method according to claim 29, comprising applying plasticiser to the filtering material before the filtering material is drawn into the shaping chamber; and/or comprising a step of expanding the filtering material before the filtering material enters the shaping chamber; and/or wherein the filtering material is drawn into a stuffer jet before entering the shaping chamber; and/or comprising a step of cutting the longitudinally extending rod of filtering material to form one or more filter element(s), mouthpiece(s) or cooling element(s).
36-38. (canceled)
Description
[0202] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
[0203] FIG. 1 is a perspective view of a mouthpiece, filter element or cooling element according to the present invention.
[0204] FIG. 2 is an end view of a mouthpiece, filter element or cooling element according to the present invention.
[0205] FIG. 3 is a perspective view of a mouthpiece, filter element or cooling element according to the present invention.
[0206] FIG. 4 is a side view of a mouthpiece, filter element or cooling element according to the present invention.
[0207] FIG. 5 is a sectional view of a mouthpiece, filter element or cooling element shown in FIG. 3.
[0208] FIG. 6 is sectional view of a mouthpiece, filter element or cooling element according to the invention.
[0209] FIG. 7 is sectional view of a mouthpiece, filter element or cooling element according to the invention.
[0210] FIG. 8 is an end view of a mouthpiece, filter element or cooling element according to the invention.
[0211] FIG. 9 is a sectional view of a mouthpiece, filter element or cooling element according to the invention.
[0212] FIG. 10 is an end view of a mouthpiece, filter element or cooling element according to the invention.
[0213] FIG. 11 is a sectional view of a mouthpiece, filter element or cooling element according to the invention.
[0214] FIG. 12 is a perspective view of a mouthpiece, filter element or cooling element according to the invention.
[0215] FIG. 13 is a schematic view of an apparatus for making a mouthpiece, filter element or cooling element in use.
[0216] FIGS. 14a and 14b are sectional views of part of the apparatus for making a mouthpiece, filter element or cooling element in use.
[0217] FIG. 1 shows a perspective view of a mouthpiece, filter element or cooling element 100 for an aerosol generating device according to an embodiment of the present invention. The mouthpiece, filter element or cooling element 100 comprises a first section 110 and a second section 120. The first section 110 comprises a longitudinally extending core 112 of filtering material in the form of a cylindrical core of filtering material. The filtering material may be cellulose acetate, although it will be appreciated that other filtering materials are also suitable The cylindrical core 112 of filtering material forming the first section includes an outer surface 116 and an inner surface (shown as 118 in FIG. 2). The outer surface 116 defines the cylindrical core and the inner surface 118 defines a channel 114. The channel 114 extends from the free end of the first section 110 and extends along the entire length of the first section 110. In the case of a filter element or mouthpiece, the channel 114 extends from the mouth end. The channel 114 has a non-circular transverse cross section, and as shown in FIG. 1, the transverse cross section is a modified circle having two protuberant portions 119. The transverse cross section varies in the longitudinal direction by rotating about a longitudinal axis of the first section 110, for example about a longitudinal axis of the channel 114. The protuberant portions 119 are formed as ridges (as shown in FIG. 2) which extend helically about the longitudinal axis L. The ridges 119 extend along the inner surface 118 that defines the channel 114 and the ridges protrude from that inner surface. The two ridges 119 are integral with the inner surface 118 and are defined by the filtering material that makes up the core. As illustrated in FIG. 1, the channel is located centrally with respect to the core 112.
[0218] Integral with the first section 110 is the second section 120. The second section 120 comprises a longitudinally extending core 122 of filtering material in the form of a cylindrical core of filtering material. The filtering material may be cellulose acetate, although it will be appreciated that other filtering materials are also suitable. The filtering material forming the second section 120 is continuous and homogenous. The filtering material forming the second section 120 is the same type of filtering material that formed the first section. The second section does not include a channel. The cylindrical core of filtering material 122 is defined by an outer surface 126.
[0219] FIG. 2 shows an end view of the mouthpiece, filter element or cooling element shown in FIG. 1, which also amounts to the end view of the first section 110. FIG. 2 illustrates the ridges 119 in more detail.
[0220] FIG. 3 shows a perspective view of the first section as illustrated in FIG. 1. As shown in FIG. 3, the core 112 extends along the longitudinal axis (L), and the channel 114 extends along the longitudinal axis L of the core 112.
[0221] FIG. 4 shows a side view of the first section along the plane defined by the y and L axis shown in FIG. 3.
[0222] FIG. 5 shows a sectional view of the first section along line A-A, as shown in FIG. 4. The channel transverse cross section shown in FIG. 5 includes a modified circle having two diametrically opposed protuberant parts which extend from the edge of the circle towards the centre of the circle. The diametrically opposed protuberant parts correspond to the ridges 119 which extend helically about the longitudinal axis of the first section 110. As shown in FIG. 5, the transverse cross section of the channel 114 is rotated with respect to the channel cross section shown at the end of the first section as shown in FIG. 3.
[0223] The ridges 119 extend helically with respect to the longitudinal axis (L) of the first section 110, so the position of the ridges 119 with respect to the circumference of the channel 114 varies along the length of the first section 110.
[0224] FIG. 6 shows a further sectional view of the first section 110 along line B-B as shown in FIG. 4. As is shown in FIG. 6, the transverse cross section of the channel 114 is rotated with respect to both the transverse cross section shown in FIG. 5 and the end cross section shown in FIG. 3.
[0225] FIG. 7 shows a sectional view of the first section of a further filter element, mouth piece or cooling element 200 according to the present invention. The filter element or mouthpiece 200 shown in FIG. 7 is similar to that shown in FIGS. 5 and 6, but includes four ridges 219 extending along the inner surface of the core 214 helically about the longitudinal axis of the first section.
[0226] FIG. 8 shows an end view and FIG. 9 shows a sectional view of the first section of a further filter element, mouthpiece or cooling element 300 according to the present invention. The first section shown in FIGS. 7 and 8 is similar to that shown in FIGS. 1 to 6, but the first section shown in FIGS. 7 and 8 has a channel 314 having a rectangular transverse cross section. The transverse cross section of the channel varies in the longitudinal direction of the core by rotating about a longitudinal axis of the first section.
[0227] FIG. 10 shows an end view and FIG. 11 shows a sectional view of the first section of a further filter element, mouth piece or cooling element 400 according to the present invention. The first section shown in FIG. 10 is similar to that shown in FIGS. 1 to 8, but the first section shown in FIGS. 10 and 11 has a channel 414 having a cross shaped transverse cross section. The transverse cross section of the channel varies in the longitudinal direction of the core by rotating about a longitudinal axis of the first section.
[0228] FIG. 12 shows a further filter element, mouthpiece or cooling element 500 according to the present invention. The filter element, mouthpiece or cooling element 500 is similar to that shown in FIG. 1 but includes a third section 130 which is integral with the second section. The first section 110 and second section 120 are the same as described above with respect to FIGS. 1-6. The third section 130 is similar to the first section 110 and includes a longitudinally extending core of filtering material in the form of a cylindrical core 132 of filtering material. The cylindrical core 132 of filtering material forming the third section includes an outer surface 136 and an inner surface. The outer surface 136 defines the cylindrical core 132 and the inner surface defines a channel 134. The channel 134 extends from the free end of the third section 130 and extends along the entire length of the third section 130. In the case of a filter element or mouthpiece, the first section channel 114 extends from the mouth end. The channel 134 has a non-circular transverse cross section, and as shown in FIG. 1, the transverse cross section is a modified circle having two protuberant portions 139. The transverse cross section varies in the longitudinal direction by rotating about a longitudinal axis of the third section, for example about a longitudinal axis of the channel 134. The protuberant portions 139 are formed as ridges which extend helically about the longitudinal axis. The ridges 139 extend along the inner surface that defines the channel 134 and the ridges 139 protrude from that inner surface. The two ridges 139 are integral with the inner surface and are defined by the filtering material that makes up the core. As illustrated in FIG. 12, the channel is located centrally with respect to the core 132.
[0229] The applicant has found that the filter element shown in FIG. 12 may be particularly suitable for use in a heated tobacco product because the channel in the first section or the third section can house a heating element and the second section and remaining section which does not house the heating element can provide filtration of the aerosol as well as act as a cooling element to cool the aerosol.
[0230] Any of the mouthpieces or filter elements illustrated in FIGS. 1 to 12 may form part of a filter which is included in a smoking article such as a cigarette. Some smoking articles, such as those containing marijuana, include a mouthpiece as described herein.
[0231] During use, smoke travels through the mouthpiece or filter element, and the smoke takes a helical path within the channel which means that smoke emerging from the mouthpiece or filter element will continues to follow a helical path, for example in the mouth of the user. The helical path taken by the smoke affects the mouthfeel of the smoke. The second section provides additional filtration of the smoke and the second section may include an additive to modify the properties of the smoke.
[0232] Any of the mouthpieces or filter elements illustrated in FIGS. 1 to 12 may also form part of a heated tobacco product or an electronic cigarette.
[0233] The cooling element as illustrated in FIGS. 1 to 12 may form part of a heated aerosol generating system which may form part of a non-combustible product, such a heated tobacco product. A heated aerosol generating system typically includes a heating element, a power source, a rod of tobacco, one or more cooling elements and a mouthpiece. The cooling element described herein may be incorporated into the heated aerosol generating system between the mouthpiece and the tobacco rod. During use, the heating element heats the rod of tobacco to form an aerosol. The aerosol then passes into the cooling element and is cooled by the cooling element. Due to the configuration of the channel, the aerosol takes a helically path through the cooling element which reduces the temperature of the aerosol. In the case of the cooling element illustrated in FIG. 12, either the first or third section may house the heating element thereby enabling the heating element and cooling element to be included in a single element.
[0234] FIG. 13 is a schematic view of the method and apparatus for making the filter elements, mouthpieces or cooling elements as described with respect to FIGS. 1 to 12.
[0235] Referring to FIG. 13, the apparatus comprises a stuffer jet 20 configured to receive filtering material 10. Spaced longitudinally from the stuffer jet is a shaping chamber 30. The space between the stuffer jet and the shaping chamber defines a filtering material expansion element in the form of a tow blooming section 25, into which filtering material expands as the filtering material exits the stuffer jet 20. A shaping rod in the form of a mandrel 60 extends longitudinally through the centre of the stuffer jet 20, the tow blooming section 25 and into the shaping chamber 30. The mandrel 60 is coupled to a first motor 70 which is configured to cause the mandrel to rotate about the central longitudinal axis of the mandrel. A second motor 80 is coupled to the mandrel and is configured to cause the mandrel 60 to reciprocate in a longitudinal direction. It will be appreciated that for the second motor 80 to cause the mandrel 60 to reciprocate while also rotate at the same time, the second motor 80 is coupled to the first motor 70 such that the second motor 80 will cause the first motor 70 to reciprocate together with the mandrel 60. Spaced longitudinally from the shaping chamber 30 is an air jet element 40 which is configured to apply a stream of fast moving air, such as compressed air, to the rod of filtering material 50 after it exits the shaping chamber 30. Spaced longitudinally from the air jet element 40 is a cutter 90 which is configured to cut the rod of filtering material 50 into one or more filter elements, mouthpieces or cooling elements 100. The mandrel 60, stuffer jet 20, tow blooming section 25 and shaping chamber 30 are described in more detail below with respect to FIGS. 14a and 14b.
[0236] Referring to FIG. 13, the method of making the filter element, mouthpiece or cooling element 100 will now be described. Tow 10 is continuously advanced in the longitudinal direction L. The tow may be cellulose acetate or another suitable filtering material. The tow may be drawn from a bale and may be pre-processed. For example, plasticiser may be sprayed directly on to the tow at a plasticising station (not shown) using methods known in the art. Alternatively, plasticiser may have been applied to the bale of tow using a separate process prior to the bale of tow being formed.
[0237] The tow 10 is advanced and flattened before entering stuffer jet 20. The stuffer 20 jet is configured to draw and gather the tow. As the tow exits the stuffer jet 20 via the stuffer jet outlet, the tow expands into a gap between the outlet of the stuffer jet 20 and the inlet of the shaping chamber 30. The tow 10 continues to advance into the shaping chamber 30 which shapes the tow into a longitudinally extending cylindrical rod 50 of filtering material. A mandrel 60 extends longitudinally through the centre of the stuffer jet 20, tow expansion section 25 and into the shaping chamber 30. The tow 10 advances around the mandrel 60, such that the mandrel 60 forms a longitudinally extending channel within the forming rod of tow.
[0238] Rotation of the mandrel 60, as the tow 10 passes through the shaping chamber 30, forms a longitudinally extending channel in which the channel cross section varies in the longitudinal direction by rotating about the central longitudinal axis of the channel.
[0239] Reciprocation of the mandrel 60 forms alternating first and second sections in the rod of filtering material. The first section comprises a longitudinally extending core of filtering material including an outer surface defining the core and an inner surface defining a channel, as described with respect to FIGS. 1 to 12. The second section comprising a longitudinally extending core of filtering material that is continuous and homogenous and does not include a channel.
[0240] The tow 10 is cured within the shaping chamber 30 by steam.
[0241] After the rod of filtering material exits the shaping chamber 30, it is treated with a fast moving stream of air by air jet element 40 to further cure the rod of filtering material 50. The rod of filtering material is subsequently cut into individual filter elements, mouth pieces or cooling elements by cutter 90.
[0242] The process and apparatus for shaping the rod of filter material, shaping the channel and forming alternating first and second sections will now be described in further detail with reference to FIGS. 14a and 14b.
[0243] FIGS. 14a and 14b show the configuration of the stuffer jet, tow expansion element, and shaping chamber in use and in a first and second configuration.
[0244] FIG. 14a shows the mandrel 60 in a first position. FIG. 14a shows the stuffer jet 20 which is a funnel shaped element having an inlet 24 and an outlet 26 for filtering material such as tow 10, and an air inlet 22 for applying fast moving air to the tow 10. The inlet 24 of the stuffer jet 20 has a larger diameter than the outlet 26 such that the stuffer jet 20 is tapered. Fast moving air passes into the stuffer jet 20 via air inlet 22 and causes the tow to advance longitudinally into and through the stuffer jet 20 where the tow is condensed into a cylinder. After the tow exits the stuffer jet via the outlet 26, the tow 10 expands into the gap 25 between the stuffer jet outlet 26 and the inlet of the shaping chamber which is spaced longitudinally from the outlet 26 of the stuffer jet 20. The expanded tow continues to advance longitudinally and enters the shaping chamber 30. The shaping chamber includes an inlet into which expanded tow enters and an outlet from which a longitudinally extending rod 50 of filtering material exits the shaping chamber 30. The shaping chamber 30 includes a steam inlet 32 through which steam enters the shaping chamber. As shown in FIG. 13a the shaping chamber includes a curing zone 35 which extends along the longitudinal length of the shaping chamber and across the width of the shaping chamber 30. The mandrel 60 extends longitudinally through the centre of the stuffer jet 20, the tow expansion element 25 and along the entire length of the curing zone 35 within the shaping chamber 30, such that the end of the mandrel 60 is in line with the end of the curing zone 35.
[0245] In this first configuration, tow 10 passes through the annular space between the mandrel 60 and the inside surface of the shaping chamber 30 to thereby form a channel extending along the length of the curing zone 35. Steam is applied to the filtering material within the shaping chamber 30 to thereby cure the filtering material by hardening the filtering material such that a first section is formed which comprises a longitudinally extending core of filtering material having an outer surface defining the longitudinally extending core of filtering material and an inner surface defining a longitudinally extending channel.
[0246] FIG. 14b shows the mandrel 60 in a second position in which the mandrel 60 is positioned rearward of the mandrel shown in FIG. 14a. In the second position, the end of the mandrel 60 is distanced longitudinally from the first position the mandrel took as shown in FIG. 14a, and the mandrel 60 does not extend along the entire length of the curing zone 35. As shown in FIG. 14b, the mandrel 60 is withdrawn to outside of the curing zone 35. In the second position, tow 10 passes into the space defined by the end of the mandrel 60 and the inner surface of the shaping chamber 30 to form a second section comprising a longitudinally extending core of filtering material without a channel.
[0247] As shown in FIG. 14b, the first section has advanced forwards and has retained its shape, including the channel, due to the steam applied to the filtering material within the curing zone 35. Accordingly, the method forms alternating first and second sections. It will be appreciated that the filtering material is advanced at a rate which is correlated with the speed at which the mandrel reciprocates such that alternating first and second sections are formed. The relative speeds of the advancing filtering material and the mandrel may be controlled by a controller (not shown).
[0248] The shape of the mandrel determines the cross sectional shape of the channel. For example, the rod used to make the mouthpiece, filter element or cooling element shown in FIGS. 1 to 6 is a cylinder which includes two diametrically opposed grooves which extend along the length of the mandrel. The mandrel used to make the mouthpiece, filter element or cooling element shown in FIG. 7 is a cylinder having two pairs of diametrically opposed grooves. The mandrel used to make the mouth piece, filter element or cooling element shown in FIGS. 8 and 9 has a rectangular cross section, and the mandrel used to form the mouthpiece, filter element or cooling element shown in FIGS. 10 and 11 has a cross shaped cross section.
[0249] The channel shape is defined by the mandrel as explained above. At all times during the method, the mandrel is rotating. Rotation of the mandrel, as the filtering material passes through the shaping chamber, forms a longitudinally extending channel in which the channel cross section varies in the longitudinal direction by rotating about the central longitudinal axis of the channel. In the case of a mandrel which includes grooves, such as used to make the mouthpiece, filter element or cooling element shown in FIGS. 1 to 6, the grooves in the mandrel define ridges on the inner surface of the core that defines the channel. The rotation of the mandrel and consequently the rotation of the grooves causes ridges to form on the inner surface of core that defines the channel. The ridges extend along the inner surface and follow a helical path about the longitudinal axis of the channel. It is possible to vary the helical pitch of the ridges by controlling the rotational speed of the mandrel and the speed at which the tow is drawn through the shaping chamber. The depth and width of each ridge may be modified by varying the depth and width of each groove in the mandrel. If additional ridges are desired, then the mandrel may include additional grooves. For example, the mouth piece, filter element or cooling element shown in FIG. 7 makes use of a mandrel having four grooves.
[0250] The diameter of the channel at its widest point may be varied by changing the diameter of the rod at its widest point. Similarly, the diameter and shape of the core of filtering material may be varied by modifying the diameter and shape of the shaping chamber.
[0251] The applicant has found that including a tow expansion element may improve the channel definition because the expanded tow is able to twist before entering the shaping chamber which aids formation of the channel as described above.
[0252] It will be appreciated that while the mandrel extends through the stuffer jet and the tow blooming section, in these sections channel formation may begin, but there is no application of heat so the filtering material does not cure. This means that a second section which does not include a channel can still be formed when the mandrel is withdrawn to the second position.
[0253] The cutting step is timed according to the type of filter element, mouthpiece or cooling element desired. For example the cutting step could be timed to form filter elements, mouthpieces or cooling elements that include a first section and section such as shown in FIG. 1. The rod of filtering material may be cut through the centre of each first section to thereby form a filter element, mouthpiece or cooling element having a first, second and third section in which the first and third sections are shorter than the second section. The rod could be cut such that each filter element, mouthpiece or cooling element includes a first section, second section and third section of the same length.
