Method and apparatus for manufacturing inductively heatable aerosol-forming rods

Abstract

The present invention relates to a method for manufacturing inductively heatable aerosol-forming rods (100). The method comprises the steps of supplying a continuous susceptor profile (20) to a continuous rod-forming process such as to enter and pass the rod-forming process along a center axis (80) of the rod-forming process, supplying a continuous substrate web (30) comprising an aerosol-forming substrate to the continuous rod-forming process such as to enter the rod-forming process laterally to the susceptor profile and passing the substrate web and the susceptor profile through the rod-forming process, thereby gathering the substrate web into a rod shape around the susceptor profile substantially coaxially to the center axis. The invention further relates to an apparatus (1) for manufacturing inductively heatable aerosol-forming rods (100). The apparatus comprises a rod-forming device (10) configured for gathering a continuous substrate web (30) comprising an aerosol-forming substrate into a rod shape around a continuous susceptor profile (20) coaxially to a center axis (80) of the rod-forming device as the substrate web and the susceptor profile pass through the rod-forming device. The apparatus further comprises a susceptor supply (21) configured for supplying the susceptor profile to the rod-forming device such as to enter and pass the rod-forming device along the center axis of the rod-forming device. The apparatus also comprises a substrate supply (35) configured for supplying the substrate web to the rod-forming device such as to enter the rod-forming device laterally to the susceptor profile.

Claims

1. Method for manufacturing inductively heatable aerosol-forming rods, the method comprising the steps of: supplying a continuous susceptor profile to a continuous rod-forming process such as to enter and pass the rod-forming process along a center axis of the rod-forming process; supplying a substrate web comprising an aerosol-forming substrate to the continuous rod-forming process such as to enter the rod-forming process laterally to the susceptor profile; passing the substrate web and the susceptor profile through the rod-forming process, thereby gathering the substrate web into a rod shape around the susceptor profile substantially coaxially to the center axis.

2. The method according to claim 1, wherein the susceptor profile is dimensionally stable.

3. The method according to claim 1, wherein the step of passing the susceptor profile through the rod-forming process comprises longitudinally guiding the susceptor profile at least along an upstream section of the rod-forming process.

4. The method according to claim 1, further comprising the step of partially gathering the substrate in a transverse direction with respect to a transport direction of the substrate web prior to gathering the substrate web into a rod shape around the susceptor profile.

5. The method according to claim 4, wherein the susceptor profile is a susceptor sheet, and wherein the susceptor sheet is substantially orthogonal to the substrate web prior to partially gathering the substrate web.

6. The method according to claim 4, wherein the substrate web includes at least two separate sub-webs, wherein the two sub-webs are supplied to the rod-forming process such as to enter the rod-forming process laterally to the susceptor profile at opposite sides of the susceptor profile.

7. The method according to claim 6, wherein the susceptor profile is a susceptor sheet, and wherein the susceptor sheet is substantially co-planar to the sub-webs prior to partially gathering the sub-webs.

8. The method according to claim 1, further comprising the step of supplying a wrapper to the rod-forming process and wrapping the wrapper around the substrate web.

9. The method according to claim 1, wherein the susceptor profile is a susceptor sheet, and wherein the susceptor sheet is substantially orthogonal to the substrate web prior to gathering the substrate web.

10. The method according to claim 1, wherein the substrate web includes at least two separate sub-webs, wherein the two sub-webs are supplied to the rod-forming process such as to enter the rod-forming process laterally to the susceptor profile at opposite sides of the susceptor profile.

11. The method according to claim 10, further comprising the steps of cutting and separating the substrate web lengthwise into the two sub-webs of the aerosol-forming substrate prior to supplying the two continuous sub-webs to the rod-forming process.

12. The method according to claim 10, wherein the susceptor profile is a susceptor sheet, and wherein the susceptor sheet is substantially co-planar to the sub-webs prior to gathering the sub-webs.

13. Apparatus for manufacturing inductively heatable aerosol-forming rods, the apparatus comprising: a rod-forming device configured for gathering a continuous substrate web comprising an aerosol-forming substrate into a rod shape around a continuous susceptor profile coaxially to a center axis of the rod-forming device as the substrate web and the susceptor profile pass through the rod-forming device; a susceptor supply configured for supplying the susceptor profile to the rod-forming device such as to enter and pass the rod-forming device along the center axis of the rod-forming device; a substrate supply configured for supplying the substrate web to the rod-forming device such as to enter the rod-forming device laterally to the susceptor profile.

14. The apparatus according to claim 13, wherein further comprising a longitudinal guide for guiding the susceptor profile along the center axis.

15. The apparatus according to claim 14, wherein the longitudinal guide extends downstream at least into an upstream section of the rod-forming device.

16. The apparatus according to claim 14, wherein an upstream end of the longitudinal guide is positioned upstream of an upstream end of the rod-forming device.

17. The apparatus according to claim 14, wherein the longitudinal guide comprises a guiding tube.

18. The apparatus according to claim 13, wherein the rod-forming device comprises at least one funnel coaxial to the center axis.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 schematically illustrates an exemplary embodiment of an apparatus according to the invention;

(3) FIG. 2 is a schematic cross-sectional view of a first embodiment of an aerosol-forming rod manufactured by using the method and the apparatus according to the invention; and

(4) FIG. 3 is a schematic cross-sectional view of a second embodiment of an aerosol-forming rod manufactured by using the method and the apparatus according to the invention.

(5) FIG. 1 schematically illustrates an exemplary embodiment of an apparatus 1 according to the invention. The apparatus 1 is configured for manufacturing aerosol-forming rods 100 comprising a susceptor profile 20 in the center which a substrate web 30 including an aerosol-forming substrate is coaxially gathered around. The apparatus 1 as shown in FIG. 1 is particularly configured for performing the method according to the invention and as described herein.

(6) Main component of the apparatus 1 is a rod-forming device 10 configured for gathering the substrate web 30 around the susceptor profile 20 coaxially to a center axis 80 of the rod-forming device 10, thus resulting in the final rod shape. The rod-forming process is a continuous process. That is, the substrate web 30 and the susceptor profile 20 enter and pass the rod-forming device 10 as continuous materials. Accordingly, gathering of the substrate web 30 around the susceptor profile 20 occurs as the substrate web 30 and the susceptor profile 20 together pass through the rod-forming device 10. The center axis 80 also defines a transport line through the rod-forming device 10.

(7) Upstream of the rod-forming device 10, the apparatus 1 comprises a substrate supply 35 for supplying the substrate web 30 to the rod-forming device 10. In the present embodiment, the substrate web 30 is provided from below, for example, from a bobbin (symbolized by the arrow pointing upwards) and deflected towards the upstream end 13 (entrance) of the rod-forming device 10 by a horizontally oriented deflection roller 36. The substrate web 30 preferably is a continuous tobacco web, for example a cast leaf. The substrate web 30 enters the rod-forming device 10 as substantially flat material. In particular, the substrate web 30 is supplied such as to enter the rod-forming device 10 below the center axis 80. As can be seen from FIG. 1, the flat sides of the web 30 are arranged substantially horizontally when entering the rod-forming device 10.

(8) The apparatus 1 further comprises a susceptor supply 21 for supplying the continuous susceptor profile 20 downstream towards the rod-forming device 10. In the present embodiment, the susceptor profile 20 is a continuous sheet 20 of a susceptor material having a rectangular cross-section, such as a continuous band made of ferromagnetic stainless steel. The susceptor profile 20 may be provided, for example, on a horizontally oriented bobbin, arranged laterally with regard to the transport line through the rod-forming device 10 (symbolized by the arrow pointing towards the center axis 80). The bobbin is part of the susceptor supply 21. The susceptor profile 20 is unwound from the bobbin and supplied from a side towards the center axis 80 upstream of the rod-forming device 10.

(9) According to the invention it has been recognized that accurate positioning of the susceptor profile 20 within the cross-section of the aerosol-forming rod 100 is crucial for an adequate heating of the substrate and thus for an adequate aerosol formation. Hence, in order to ensure an accurate positioning, the susceptor profile 20 is supplied to the rod-forming device 10 such as to enter and pass the rod-forming device 10 along the center axis 80. Due to the central positioning, the susceptor profile 20 is accurately placed at its desired final position within the aerosol-generating rod, that is, coaxially to, in particular on-axis with a center axis of the aerosol-generating rod 100. To achieve the central positioning, the susceptor supply 21 according to the present embodiment comprises a vertically oriented deflection roller 22 which is arranged and configured such as to deflect the susceptor profile 20 towards to the center axis 80. Thus, the susceptor profile 20 is positioned along the center axis 80 having the flat sides of the susceptor profile 20 arranged substantially vertically. In particular, the susceptor profile 20 is positioned on-axis with regard to the center axis 80 of the rod-forming device 10. That is, a longitudinal axis of the susceptor profile 20 extending through a center of mass or a geometric center of the susceptor profile 20 is coaxial to the center axis 80 of the rod-forming device 10. In particular, the susceptor profile 20 is already pre-positioned on-axis upstream of the continuous rod-forming device and prior to getting into contact with the substrate web 30. Thus, the pre-positioned susceptor profile 20 defines a physical center for the rod-forming process which the substrate web 30 is coaxially gathered around. Advantageously, this causes the rod-forming process to be reliable and reproducible with regard to an accurate center position of the susceptor within the surrounding substrate.

(10) As mentioned above, the substrate web 30 is supplied such as to enter the rod-forming device 10 below the center axis 80 of the rod-forming device 10. That is, the substrate web 30 enters the rod-forming device 10 laterally to the susceptor profile 20. In particular, the substrate web 30 enters the rod-forming device 10 alongside the susceptor profile 20 at an angle of zero degrees, that is, parallel to the center axis 80. Alternatively the substrate web 30 may enter the rod-forming device 10 from below towards the susceptor profile 20, that is, at an angle greater than zero degrees to the center axis 80, for example at an angle of 5 degrees. In that case, a width extension of the substrate web 30—prior to being gathered—preferably still extends horizontally though the substrate web 30 ascends upward at angle along its length extension.

(11) In any case, having the substrate web 30 entering the rod-forming device 10 laterally to the susceptor profile 20 advantageously ensures that there is little or essentially no divergence of the susceptor profile 20 from its pre-defined on-axis position upon entering the rod-forming device 10. In particular, having the substrate web 30 arranged substantially horizontally below the susceptor profile 20 and the susceptor profile 20 arranged substantially vertically advantageously facilities gathering, in particular folding the substrate web 30 symmetrically around the left flat side and the right flat side of the susceptor profile 20. Furthermore, as the substrate web 30 is arranged below the susceptor profile 20 the substrate web 30 advantageously supports the susceptor profile 20 as both pass through the rod-forming device 10. This also facilitates to keep a stable position of the susceptor profile 20 along the center axis 80.

(12) In the present embodiment, the rod-forming device 10 comprises two stages, a first stage 11 defining an upstream section of the device 10, and a second stage 12 defining a downstream section of the device 10. The first stage 11 comprises a frustum-shaped funnel 71 arranged coaxially to the center axis 80. A circular inner cross-sectional profile of the funnel 71 continuously decreases from an upstream end 13 towards a downstream end 14 of the funnel 71. The funnel 71 gathers the substrate web 30 in a transverse direction with respect to a transport direction of the substrate web 30 or a length extension of the substrate web 30, respectively. Upon having passed the first stage 11, the substrate web 30 is partially gathered but has not yet assumed the final rod shape.

(13) In order to prevent the susceptor profile 20 from being displaced from the center axis 80 as passing through the rod-forming device 10, the apparatus 1 further comprises a longitudinal guide 23 for guiding the susceptor profile 20 along the center axis 80. In the present embodiment, the longitudinal guide is a guiding tube 23 extending coaxially to the center axis 80 through the entire funnel 71.

(14) The guiding tube 23 also extends in the upstream direction beyond an upstream end 13 of the funnel 71. That is, an upstream end 24 of the guiding tube 23 is positioned upstream of the funnel 71. Advantageously, this supports an accurate pre-positioning and guiding of the susceptor profile 20 along the center axis 80 prior to entering the rod-forming device 10.

(15) Advantageously, the guiding tube 23 ends at a downstream position where the susceptor profile 20 preferably is at least partially surrounded and thus supported by the partially gathered substrate web 30. In the present embodiment, a downstream end 25 of the guiding tube 23 is positioned adjacent to an upstream end 15 of the second stage 12.

(16) The second stage 12 of the rod-forming device is configured for completing the step of gathering the substrate web 30 coaxially around the susceptor profile 20 into the final rod shape. In the present embodiment, the second stage 12 comprises a semi-funnel 72 arranged above the center axis 80 which comprises a rod-forming concave surface having a C-shaped cross-section. The C-shaped cross-section progressively decreases in size downstream from the upstream end 15 to a downstream end 16 of the second stage 12. The second stage 12 further comprises a conveyor belt 17, in the present embodiment a garniture tape 17, which interacts with the semi-funnel 72 to form the final rod shape. For this, the garniture tape 17 progressively takes a cross-sectional U-shape as it runs along the second stage 12 downstream below the center axis 80. In operation, the U-shaped garniture tape 17 in combination with the semi-funnel 72 gathers the partially pre-gathered substrate web 30 coaxially around the susceptor profile 20 into the final circular rod shape.

(17) In addition, a paper wrapper 51 is supplied from a wrapper supply 50 into the upstream end 15 of the second stage 12. As can be seen from FIG. 1, the wrapper 51 is supported on a top surface of the garniture tape 17 which faces the center axis 80. Thus, in operation the wrapper 51 is automatically wrapped around the substrate web 30 as the latter is progressively gathered around the susceptor profile 20. Preferably, glue is added to at least one longitudinal edge of the wrapper 51 for connecting both longitudinal edges of the wrapper upon being wrapped around the rod-shaped material of the substrate web 30. Thus, the wrapper 51 serves to stabilize the final rod shape. For adding glue and connecting the longitudinal edges of the wrapper 51, the rod-forming device 10 according to the present embodiment comprises a folding and compressing device 18 downstream of the second stage 12.

(18) At a downstream end 19 of the overall rod-forming device 10, the device 10 provides a continuous aerosol-forming rod 100 having the final rod-shape in which the substrate web 30 is fully gathered around the susceptor profile 20 and entirely surround by the wrapper 51.

(19) Downstream of the rod-forming device 10, the apparatus 1 further comprises a cutting device 60 for cutting the continuous rod 100 into inductively heatable aerosol-forming rod segments 101.

(20) FIG. 2 shows a cross-sectional view of a continuous aerosol-forming rod 100 or rod segment 101, respectively, manufactured using the apparatus and the method as illustrated in FIG. 1 and described before. The circular cross-section of the rod shape may have a diameter between about 4 millimeters and about 10 millimeters, in particular, between about 5 millimeters and about 8 millimeters. The rectangular shape of the susceptor profile 20 preferably has a width extension between about 2 millimeters and about 8 millimeters, in particular between about 3 millimeters and about 5 millimeters, and a thickness extension between about 0.03 millimeter and about 0.15 millimeter, more preferably between about 0.05 millimeter and about 0.09 millimeter. As can be seen from FIG. 2, the susceptor profile 20 is positioned substantially symmetrically with regard to a center 81 of the circular cross-section of the rod-shape. This position is preferred with regard to a homogeneous, in particular symmetric and reproducible heat distribution in the aerosol-generating rod. Thus, heat generated in the susceptor profile 20 symmetrically dissipates into the circumferential periphery of the susceptor profile 20 allowing to homogeneously heat-up the aerosol-forming substrate of the substrate web 30 gathered around. As can be further seen from FIG. 2, the substrate web 30 is substantially symmetrically gathered from below around a left and a right flat side of the susceptor profile 20. This is due to supplying the susceptor profile 20 substantially vertically along the center axis 80 and the substrate web 30—as a single web—substantially horizontally below the center axis 80.

(21) With reference to FIG. 3, a modification of the method according to the invention is described hereafter. Instead of supplying the substrate web 30 as a single web, the substrate web 30 may be alternatively supplied as two sub-webs 31, 32. The two sub-webs 31, 32 may be a starting material of the overall process. For example, each sub-web 31, 32 may be provided on a separate bobbin. Alternatively, a single substrate web may be a starting material which is divided into two sub-webs 31, 32 upstream of the rod-forming device. In both cases, the two sub-webs 31, 32 preferably are supplied separately to the rod-forming device. In particular, the two sub-webs 31, 32 are supplied to the rod-forming device such as to enter the device laterally to the susceptor profile 20 at opposite sides of the susceptor profile. That is, the susceptor profile 20 is sandwiched between the two sub-webs 31, 32.

(22) In case of a flat susceptor profile 20, the two sub-webs 31, 32 and the susceptor profile 20 are preferably supplied to the rod-forming device such that the susceptor profile is substantially co-planar to the sub-webs 31, 32 prior to gathering the sub-webs 31, 32 around the susceptor profile 20. Advantageously, this facilitates to ensure that the substrate material is substantially symmetrically gathered around both flat sides of the susceptors sheet 20.

(23) Even more preferably, the two sub-webs 31, 32 and the susceptor profile 20 are supplied to the rod-forming device in a substantially horizontal arrangement. Advantageously, this enables the lower sub-web 31 to support the susceptor profile 20 which in turn proves advantageous for keeping a stable position of the susceptor profile 20 along the center axis 80. FIG. 3 shows a cross-sectional view of an aerosol-forming rod 100 or rod segment 101, respectively, which has been manufactured accordingly.