CLOSED LOOP SYSTEM AND METHOD FOR CONTROLLING A POSITION OF A SUSCEPTOR IN AN AEROSOL-GENERATING ARTICLE

Abstract

A closed-loop system for controlling a position of a susceptor in an aerosol-generating article, the system comprising: a supply for continuous sheet material, a supply for a continuous susceptor, a crimping device for crimping the continuous sheet material, a shaping device for gathering the continuous sheet material and for forming the continuous sheet material with inserted continuous susceptor into a continuous rod. The system also comprises a cutting device for cutting the continuous rod into aerosol-generating articles and a control unit comprising an output control for detecting a condition of the susceptor in an aerosol-generating article, and for comparing a detected condition with quality specifications. The system further comprises a positioning device for manipulating the position of the continuous susceptor or a crimping depth adjuster, wherein the control unit is adapted for triggering the positioning device to adjust the position of the continuous susceptor or for triggering the crimping depth adjuster to adjust a crimping depth of the sheet material in the crimping device, when the detected condition do not meet quality specifications

Claims

1-15. (canceled)

16. A closed-loop system for controlling a position of a susceptor in an aerosol-generating article, the system comprising: a supply for continuous sheet material; a supply for a continuous susceptor; a crimping device for crimping the continuous sheet material; a shaping device for gathering the continuous sheet material and for forming the continuous sheet material with inserted continuous susceptor into a continuous rod; a cutting device for cutting the continuous rod into aerosol-generating articles; a control unit comprising an output control for detecting a condition of the susceptor in an aerosol-generating article, and for comparing a detected condition with quality specifications; wherein the system further comprises a positioning device for manipulating the position of the continuous susceptor or a crimping depth adjuster, wherein the positioning device is movable relative to a supply direction of the continuous susceptor, wherein the positioning device is movably arranged to be movable in three directions perpendicular to each other, wherein the positioning device includes rotation means for rotating the continuous susceptor along a longitudinal direction of the continuous susceptor, and wherein the control unit is adapted for triggering the positioning device to adjust the position of the continuous susceptor or for triggering the crimping depth adjuster to adjust a crimping depth of the sheet material in the crimping device, when the detected condition do not meet quality specifications.

17. The closed-loop system according to claim 16, wherein the detected condition of the aerosol-generating article comprise any one or several of: a position of the susceptor in the aerosol-generating article, a form of the susceptor in the aerosol-generating article, an eccentricity of the susceptor in the aerosol-generating article or a shape of gathering of sheet material surrounding the susceptor.

18. The closed-loop system according to claim 16, wherein the output control is adapted to capture information of a cross-section of at least one end of the aerosol-generating article.

19. The closed-loop system according to claim 16, wherein the positioning device is moveably arranged in the shaping device.

20. The closed-loop system according to claim 16, wherein the positioning device has the shape of a cone.

21. The closed-loop system according to claim 16, wherein the crimping depth adjuster is adapted to vary a distance between two interacting crimping elements of the crimping device.

22. The closed-loop system according to claim 16, wherein the control unit further comprises a moisture sensor for measuring a moisture of the continuous sheet material, and wherein the control unit is adapted for triggering the crimping depth adjuster to adjust a crimping depth of the sheet material in the crimping device, depending on a measured moisture content of the continuous sheet material.

23. A method for controlling a position of a susceptor in an aerosol-generating article, the method comprising: providing a continuous sheet material; crimping the continuous sheet material; providing a continuous susceptor; gathering the continuous sheet material and inserting the continuous susceptor into the continuous sheet material thereby forming a continuous rod; cutting the continuous rod into aerosol-generating articles; performing an output control, thereby detecting a condition of the susceptor in an aerosol-generating article and comparing a detected condition with quality specifications; thereby, when the detected condition do not meet quality specifications for an aerosol-generating article: adjusting a position of the continuous susceptor by moving the continuous susceptor along three directions perpendicular to each other and/or by rotating the continuous susceptor along a longitudinal direction of the continuous susceptor or adjusting a crimping depth of the continuous sheet material.

24. The method according to claim 23, therein capturing information of a cross-section of the aerosol-generating article.

25. The method according to claim 23, comprising adjusting the position of the continuous susceptor, while gathering the continuous sheet material.

26. The method according to claim 23, comprising adjusting the position of the continuous susceptor by guiding the continuous susceptor in and along a movable positioning device.

27. The method according to claim 23, therein measuring a moisture content of the continuous sheet material and adjusting the crimping depth depending on the moisture content of the continuous sheet material.

28. The method according to claim 23, therein providing a continuous sheet material in the form of a non-aerosol forming sheet material and changing the non-aerosol-forming sheet material into an aerosol-forming sheet material by adding an aerosol-forming substance to the non-aerosol-forming sheet material before forming the continuous rod.

Description

[0268] Examples will now be further described with reference to the figures in which:

[0269] FIG. 1 shows a schematic closed loop control system;

[0270] FIG. 2 shows a schematic cross section along a shaping device with positioning device;

[0271] FIG. 3 shows a crimping closed loop control system;

[0272] FIG. 4 shows an output control;

[0273] FIG. 5 shows a cross section of a rod-shaped article with position control; and

[0274] FIG. 6 shows a cross section of a rod-shaped article with eccentricity and deformation control.

[0275] FIG. 1 illustrates a manufacturing line for aerosol-generating articles and a closed control loop system for a position control of a susceptor in a crimped and gathered sheet material forming the aerosol-generating article.

[0276] In FIG. 1, black arrows 77 indicate a physical flow of products. Dotted arrows 88 indicate information flow from various measurement devices 81,82,83,84,85,86,89 including sensors to the control unit 8. The two dash-dotted arrows 99 indicate information flow from the control unit 8 to actuators of the crimping device 4 or to the positioning device 6 in the shaping device 5, which may be embodied as cone formation module.

[0277] In the supply unit 7, a continuous sheet material, for example a tobacco containing sheet material, in particular a cast leaf, is unwound from a bobbin. In an optional flavour module 78, flavours, but also nicotine, aerosol-formers or other substances may be applied to the continuous sheet material. For example, with the flavour module 78, an originally non-aerosol-forming sheet material may be changed into an aerosol-forming sheet material and this into an aerosol-forming substrate.

[0278] The sheet material is further transported to a crimping device 4, where the sheet material is crimped. The sheet material is preferably provided with longitudinal crimps along the length and transport direction of the sheet material. Further downstream in the manufacturing line, a susceptor band insertion module 76 is arranged. The susceptor band insertion module 76 is preferably integrated in a shaping device 5, which shaping device 5 also includes a positioning device 6 for the susceptor band in the partially gathered sheet material. With the positioning device 6 the position of the continuous susceptor relative to the sheet material may be adjusted. In the shaping device 5, the aerosol-forming sheet material is gathered, mainly along the crimps and aerosol-forming sheet material and the susceptor are formed into a continuous rod, The continuous rod is further downstream cut into individual rod-shaped articles in the cutting device 79. The articles may, for example be single or double rods of aerosol-generating articles, thus having single or double length.

[0279] The cut rods are subject to an output control 86. The output control 86 is preferably a visual inspection of a cross-section of the rod. The output control 86 controls the condition of the susceptor in the rod-shaped article, preferably mainly by controlling the position of the susceptor in the article. The measured and determined conditions of the susceptor are compared with quality specifications in the output control 86 or in the control unit 8.

[0280] The information of the output control 86 is fed to the control unit 8. The control unit 8 will, dependent on the result of the quality control, send according signals to the positioning device 6 or to the crimping device 4, or to both, the positioning device 6 and the crimping device 4, in order to adjust the position of the continuous susceptor into the sheet material upon rod forming, or to adjust a crimping depth of the sheet material in the crimping device 4.

[0281] Next to the output control 86, the various measurement devices 81,82,83,84,85,89 arranged along the manufacturing line may provide input for the control unit 8. This information may be used to adjust the individual devices 7,78,4,5,6,76,79 arranged along the manufacturing line. The various measurement devices 81,82,83,84,85,89 are: [0282] A measurement device 81 for detecting the travel position of the sheet material, such as a left or right deviation from a central transport direction. A deviation of the travel position of the sheet material may be corrected by repositioning the sheet material to a more central transport direction. Information of a deviation of the travel position of the sheet material may also be input into other further downstream arranged devices, such as for example, the flavour module 78. [0283] A measurement device 82 for measuring a width and a thickness of the sheet material. This information may, for example, be used in the crimping device 4 and the susceptor strip insertion module 76. Exemplary values for a cast leaf are a width of 125 mm and a thickness of 200 m. [0284] A discoloration measurement device 83, for example following the flavour module 78; [0285] A measurement device for measuring a crimping depth 84 and a moisture sensor 87 measuring the moisture content of the sheet material. While humidity information of the sheet material may have a significant influence on the crimping process, information on the crimping depth may directly be used for adjusting the distance of crimping elements in the crimping device 4. An exemplary value for a crimping depth for a cast leaf is 250 m (mean peak; thickness of 200 m) at a moisture content of 8 percent of water. [0286] An impedance measurement device 89 may be provided to control the susceptor before the susceptor is inserted into the sheet material. By this measure, it may be avoided that defective susceptors or susceptors of inadequate quality are used for the manufacturing of articles. An exemplary value for a metallic susceptor sheet impedance and resistance is 600 mOhm.

[0287] A resistance measurement device 85 is provided at the location of the susceptor strip insertion module 76. The resistance measurement device 85 measures an insertion resistance of a susceptor into the sheet material. A high insertion resistance may deform a susceptor during the insertion process or may result in a susceptor having an insufficient insertion depth in the sheet material. Adjusting, for example, the location, where the susceptor is inserted into the sheet material, may reduce said risks as the sheet material is more or less densely gathered in a more upstream or more downstream location.

[0288] The system shown in FIG. 1 comprises several measurement devices arranged along the manufacturing line of aerosol-generating articles. These devices may be present to enhance the accuracy and reliability of the system but may also be optional, may be positioned at other process stages of the manufacturing line or of the control system, or may, for example, be duplicated to be available also at other process stages in the manufacturing line. As an example only, the moisture sensor 87 may be provided before or upon supplying the sheet material, shortly before crimping the sheet material or after crimping the sheet material but before rod formation. A moisture sensor may also be provided at some or all of these locations. It has also been found that width and thickness of the sheet material have a minor impact on the crimping process of the sheet material, such that measurement device 82 may possibly be omitted. In addition, for example, the insertion module 76 for susceptor insertion also comprises a positioning device. Preferably, deviations from a reference in a range of about 0.2 millimeter distance from a reference travel distance are detected.

[0289] FIG. 2 is a schematic view of a shaping device 5 in the form of a shaping cone 51. In the shaping cone 51, a continuous crimped sheet material 70 is gathered and a continuous susceptor 72 is inserted into the partially gathered continuous sheet material 70. Both materials are formed into a continuous rod 71. The continuous susceptor 72 is preferably centrally arranged in the rod 71 along a central longitudinal axis of the rod and entirely surrounded by sheet material 70. Preferably, the continuous susceptor 72 is arranged in between crimps or folds of the partially gathered aerosol-forming sheet material 70.

[0290] The continuous crimped sheet material 70 may, for example, be an aerosol-forming sheet, such as, for example, a cast leaf comprising homogenized tobacco material and an aerosol-former. The continuous susceptor 72 may be a continuous metal band, for example a ferromagnetic stainless-steel band.

[0291] A positioning device 6 in the form of a movable cone 61 is arranged in the shaping cone 51. The outlet 52 of the shaping cone 51 of the shaping device 5 is co-centrically arranged with the outlet 63 of the movable cone 61 of the positioning device 6. The two outlets 52,63 may, but are generally not arranged at a same position along the X-axis, which X-axis corresponds to the travel direction of the sheet material 70 and the susceptor 72 in FIG. 2. Generally, the outlet 63 of the movable cone 61 is arranged upstream of the outlet 52 of the shaping cone 52.

[0292] The movable cone 61 guides the continuous susceptor 72 during insertion of the susceptor 72 into the sheet material 70 and by this defines the position of the susceptor in the rod 71.

[0293] The positioning device 6 preferably comprises linear guides, which allow to adjust the position of the movable cone 61 along X,Y,Z-direction, which axes are perpendicular to each other. Preferably, by adjusting the position of the movable cone 61, direction and orientation of the susceptor may be changed in real time. For example, the outlet 63 of the movable cone 61 has a form corresponding to the form of the cross-section of the continuous susceptor. By this, the susceptor is closely guided and any movement of the movable cone is directly transferred to the continuous susceptor.

[0294] The positioning device 6 is movable along the X-direction and it is also possible to vary a tilting angle 62 between positioning device 6 and shaping device 5.

[0295] The positioning device 6, in particular the movable cone 61 may also be rotatable, preferably around the longitudinal middle axis of the cone 61.

[0296] In FIG. 2, the X-direction is parallel to the travel direction of the sheet material 70. The Y-direction directs to the lateral sides of the travel direction of the sheet material 70 and perpendicular to the travel direction. The Z-direction directs to the top/down directions compared to the travel direction of the sheet material and is perpendicular to the travel direction.

[0297] FIG. 3 illustrates an example of a control loop of a crimping process of a continuous sheet material 70. The same reference signs are used for the same or similar elements as in FIG. 1.

[0298] Before the sheet material 70 is crimped, humidity, possibly also width and thickness measurements, are performed in an according measurement device, indicated by moisture sensor 87.

[0299] The sheet material 70 is then crimped in the crimping device 4 by passing in between two crimping rollers 41. The distance 40 between the crimping rollers 41 is measured and may be adjusted for adjusting a crimping depth 42 of the sheet material 70.

[0300] The information of the moisture sensor 87 is compared with reference data stored in the control unit 8. The reference data comprise settings for the crimping device 4, namely crimping roller distances 40 for specific sheet material, for example specific compositions of the sheet material, such as tobacco blends used in a tobacco material containing sheet material at specific moisture contents.

[0301] The graph indicated in the top right square in FIG. 3 indicated as control unit 8, shows crimping depth values d against moisture content M. For example, a low, medium or high moisture content M corresponds to target crimping depth values 43 between 0.20 millimeter and 0.23 millimeter. A low moisture content refers to a moisture M of lower than 7.6 percent of water and a high moisture content refers to a value M higher than 8.5 percent of water in a sheet material such as for example case leaf.

[0302] In a crimping depth measurement device 84, arranged downstream of the crimping device 4, for example, a depth profiler, the crimping depth 42 is measured. The target crimping depth 43 is compared with the measured crimping depth 42. Information of a deviation 44 of these values is provided to the control unit 8, which control unit 8 may give an according signal 99 to an actuator of the crimping device 4 to adjust the distance 40 of the crimping rollers 41. A distance 40 of crimping rollers 41 may, for example, be measured with laser sensors.

[0303] In the example shown, a measured moisture content M gives a target crimping depth value 43 of 0.204 millimeter. A measured crimping depth 42 in the measurement device 84 gives a measured crimping depth 42 of 0.173 millimeter. Thus, with this information, the distance 40 of the crimping rollers 41 in the crimping device 4 may be set to 0.2 millimeter.

[0304] In an output control 86, also the cross section of the gathered rod is measured. Next to information on the position of the susceptor in the rod, also information on the gathering of the sheet material may be determined. For example, a homogeneous or non-homogeneous gathering over the cross-section of the rod may be detected. In the exemplary drawing shown left in the square indicating the output control 86, an acceptable result 91 showing a homogeneous gathering of the sheet material over the cross-section of the rod may be seen. In the exemplary drawing shown in the middle of the square indicating the output control 86, a non-acceptable result 92 is shown. The non-acceptable result shows a cross section of an article including an area 921 not comprising sheet material. Articles delivering non-acceptable results 92 may be rejected. A rejection may be actuated by an according signal from the control unit 8 actuating a rejection device (not shown). Information on acceptable or non-acceptable results 91,92 are also used in the control unit 8 for a crimping depth adjustment.

[0305] FIG. 4 shows an example of an output control 86 including an image sensor 2, for example a camera. The camera takes pictures of the cross section of an end 730 of a rod-shaped article 73, for example, a double rod of an aerosol-forming article. By this, the position of the susceptor 74 in the double rod may be measured and compared with quality specification in order to detect or determine the condition of the susceptor.

[0306] In FIG. 4, the rod-shaped articles 73 are transported in flutes of a fluted conveyor drum 30 and preferably continuously pass the camera for position measurements. The articles 73 may be exactly positioned on the conveyor drum 30, such that a susceptor 74 in the article 73 has a specific and predefined orientation on the conveyor drum 30 relative to and when passing the camera. This may simplify a quality control. In particular, it may enhance the velocity for a comparison of measurements with quality specifications, in particular with predefined thresholds for acceptance or rejection of the article 73. A predefined and consistent orientation of the susceptor in the article may also be advantageous for further processes further downstream in the manufacturing line, such as, for example, a cutting of the article or an assembly of the article with further segments of an aerosol-generating product or device.

[0307] In FIG. 5 and FIG. 6 examples of different measurements of the condition of a susceptor 74 in the rod-shaped article 73 are shown.

[0308] In FIG. 5 and FIG. 6, pictures of cross sections of a rod-shaped aerosol-forming article 73, comprising a susceptor strip 74 surrounded by crimped and gathered aerosol-forming sheet material 75, for example cast leaf, is shown. The susceptor strips 74 are not entirely straight and not exactly in the central longitudinal axis of the article 73. In FIG. 5, two rectangles 201, 202 indicate limits for quality specifications. The two rectangles 201, 202 are symmetrically arranged around the central axis of the rod and indicate border distances for the susceptor strip position in the article 73.

[0309] The inner rectangle 201 may, for example, indicate a warning threshold, indicating a measured article 73 comprising a susceptor position outside of the inner rectangle 201. These articles are still considered acceptable. However, if a certain percentage of articles 73, for example, 5 percent to 20 percent, are outside of the inner rectangle 201 and thus exceeding the warning threshold, the control unit 8 may activate a positioning device 5 to adjust the position of the susceptor 74 upon insertion into the sheet material 75. Alternatively, or in addition, the control unit 8 may activate a crimping device 4 to adjust a crimping depth 40 of the sheet material 75 before insertion of the continuous susceptor band into the sheet material 75.

[0310] The outer rectangle 200 may, for example, be a waste threshold. If a controlled article provides susceptor positions outside of the outer rectangle 200, thus exceeding a waste threshold, the article 73 is rejected.

[0311] Preferably, a position of the susceptor 73 is adjusted or a crimping depth 40 is adjusted before a waste threshold increases.

[0312] In FIG. 6, the susceptor strip 74 is bent and displaced out of the center axis of the article 73.

[0313] The output control 8 may include eccentricity measurements or deformation measurements of the susceptor 74. For example, a center 202 and the lateral ends 203 of the susceptor 74 (lateral with respect to the cross-sectional view) may be detected. From these measurements general displacement and range of bending of the susceptor 74 may be detected and compared with acceptable ranges of predefined quality specifications. Several measurements along the susceptor 74 may enhance the accuracy of the susceptor position over the cross section of the article.

[0314] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term about. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A5% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.