Closed Loop System and Method for Controlling a Position of a Susceptor in an Aerosol-Generating Article

The present disclosure relates to a closed loop system and method for controlling a position of a susceptor in an aerosol-generating article, in particular in a rod-shaped aerosol-generating article. In particular, the disclosure relates to such a system and method in a manufacturing process of an aerosol-generating article.

For inductively heated tobacco consumables, an inductively heatable susceptor has to be provided in an aerosol-forming substrate. A susceptor should be allocated in the center of a rod-shaped article and should not be damaged or deformed. The position and integrity of the susceptor in the consumable may alter a heating efficiency, a temperature distribution or may lead to inconsistency of the performance of the consumable. Also a reduction of waste may be achieved by enhancing the quality of the manufactured consumables.

Thus, there is need for a system and method to manufacture aerosol-generating articles that allow for consistent positioning of a susceptor in an aerosol-generating article, in particular at high production volume.

According to an aspect of the present invention, there is provided a closed-loop system for controlling a position of a susceptor in an aerosol-generating article. The system comprises: a supply for continuous sheet material;

The closed-loop system according to the invention measures, preferably in real time, a condition of a susceptor in a manufactured aerosol-generating article. This information is used to adjust production parameters to keep the susceptor in the predefined position in the manufactured article. Preferably, the predefined position of the susceptor corresponds to a central position in the article.

Adjustable production parameters are either a positioning of the continuous susceptor when said continuous susceptor is inserted in the continuous sheet material upon rod forming or it is an adjustment of a crimping depth of the continuous sheet material. Adjustable production parameters may be both a positioning of the continuous susceptor when said continuous susceptor is inserted in the continuous sheet material upon rod forming and an adjustment of a crimping depth of the continuous sheet material.

Thus, at least one, preferably several physical properties of the articles being produced are measured or determined and used to adjust other production parameters to keep the susceptor in the predefined position.

The output control may detect, for example, an absolute position of the susceptor in the article. For example, the output control may detect a displacement of the susceptor out of the center of the article and in the direction of the circumference of a rod-shaped article. The output control may also detect a form of the susceptor, for example if the susceptor has a deformed, for example bent, shape. These parameters have to be within a certain predefined threshold in order to be acceptable and accepted by the output control or in the control unit, respectively. If the predefined threshold is exceeded, the article is detected as not meeting the predefined quality specifications. Depending on acceptable deviations from a threshold, for example a percentage of articles exceeding the predefined threshold, adjustment signals to the positioning unit or the crimping depth adjuster may be given and a position of the susceptor is adapted. Alternatively, if a threshold is exceeded the article may be rejected as waste.

Preferably, the output control comprises a rejection system, rejecting defective articles that comprise conditions of the susceptor that do not meet at least minimum quality specifications.

Preferably, the output control is adapted for rejecting the aerosol-generating article as waste when the detected condition of the susceptor exceed a predefined waste threshold. Thus, a waste threshold may correspond to minimum quality specifications that must be fulfilled in order for an article to be acceptable.

The detected condition of the aerosol-generating article may 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. An absolute displacement of the susceptor from a center of the article to a more radial position in the rod, a deformation of the susceptor, in particular a deformation of the cross-section of the susceptor or a bending of a susceptor band or also an inhomogeneous distribution of the gathered sheet material around the susceptor may lead to inhomogeneous heating of the aerosol-forming substrate of the article.

Accordingly, the output control is preferably adapted to capture information of a cross-section of the aerosol-generating article.

Preferably, the output control is adapted to capture information of a cross-section of at least one end of the aerosol-generating article. The output control may also be adapted to capture information of a cross-section of both ends of the aerosol-generating article.

To detect the condition of the susceptor in the article, the output control may comprise any detection system suitable for capturing information on the condition of the susceptor in the article, in particular of the position of the susceptor in in the article, for example on the cross-section of the susceptor in the article. The output control may comprise, for example, an optical system, an infrared system, an X-ray system or an induction detection system.

Preferably, the output control comprises one or several cameras.

The output control may comprise a detection system to determine the orientation of the susceptor in the article for positioning the article to be controlled by the output control in a defined control position. The information on the orientation of the susceptor in the article may either be used as correction factor in the output control when determining the condition of the susceptor in the article. Alternatively, the information on the orientation of the susceptor may be used to align the articles, for example before capturing information on a cross-section of an end of the article.

For example, a visual system may detect an overlap of a wrapper wrapping the rod-shaped aerosol-generating article. In a manufacturing process of the continuous rod of aerosol-forming substrate containing a continuous susceptor, a mutual position of continuous wrapping material relative to its content remains substantially constant. Thus, by visually detecting an overlap, rough information on the position of the susceptor in the article may be gained. This may be used for adapting a detection system to an orientation of the susceptor in the article to perform the output control. An orientation of the susceptor in the article may also be gained by other means, for example by induction means, infrared means or similar. Accordingly, the closed-loop system, in particular the control unit may comprise article rotation means for rotating the articles in order to align them preferably all at a same orientation for passing the output control.

In addition, a position of the susceptor, in particular or a susceptor band, that is defined and consistent for all articles may be advantageous or even mandatory for articles that have to be cut or processed otherwise, for example for assembly with other segments, wherein a specific mutual relative position of the susceptor band with another segments is desired or mandatory. It has been found that a random orientation of a susceptor band in the article may lead to irregular cutting, deformation of the susceptor or even a reduced lifetime of a cutting knife. It has been found that the relative position of a susceptor band with respect to a cutting knife has a large impact on the quality of the cut.

Thus, a defined position of the article corresponds to an optimized cutting angle of the susceptor band with respect to the cutting device. Accordingly, it may be beneficial to provide an optimized rotational positioning of the article for the output control but also before cutting the article or otherwise further processing the article.

As mentioned above, the position of a continuous susceptor in the sheet material may be adjusted by a positioning device or by a crimping depth adjuster. In some embodiments of the closed-loop system, the system comprises the positioning device and the crimping depth adjuster. Accordingly, in these embodiments, the control unit is adapted for triggering the positioning device to adjust the position of the continuous susceptor and for triggering the crimping depth adjuster to adjust the crimping depth of the sheet material in the crimping device, if the detected condition do not meet quality specifications.

The closed-loop system may comprise a positioning device directly manipulating the position of the continuous susceptor when the susceptor is combined with the continuous sheet material. For example, the position of the continuous susceptor may be adjusted upon insertion of the continuous susceptor into partially gathered sheet material. Preferably, insertion and positioning of the continuous susceptor occurs in the shaping device while or upstream of the rod forming process.

Preferably, the continuous susceptor is guided by the positioning device. Preferably, position of the continuous susceptor is adjusted by moving the positioning device.

The positioning device may be movably arranged to be movable in at least two directions perpendicular to each other, for example along an x-axis and y-axis.

Preferably, the positioning device is movable relative to a supply direction of the continuous susceptor. Thus, the x-axis may correspond to a transport direction of the continuous materials along a manufacturing line. This allows to change an insertion position of the continuous susceptor into the partially gathered sheet material. Adjusting the location, where the continuous susceptor is inserted into the sheet material, may result in insertion of the continuous susceptor in more or less densely gathered sheet material in a more upstream or more downstream location along the rod forming process. By this, an insertion depth in the sheet material may be adjusted or an insertion resistance may be reduced. By reducing an insertion resistance, also risk that the continuous susceptor is damaged upon insertion into the sheet material may be reduced.

Preferably, the positioning device is movable in three directions perpendicular to each other. This allows an adjustment of the position of the continuous susceptor in all three dimensions.

In order to combine a rod-forming and an adjustment of the position of the continuous susceptor, preferably, the shaping device and the positioning device are combined.

Preferably, the positioning device is moveably arranged in the shaping device.

The positioning device may also include rotation means for rotating the continuous susceptor along a longitudinal direction of the continuous susceptor.

Preferably, the positioning device is rotatable and thereby rotating the continuous susceptor. For example, the positioning device may comprise an opening, where the continuous susceptor passes through. The opening of the positioning device may have a shape corresponding to the shape of the cross-section of the continuous susceptor. When the positioning device is rotated or sideways displaced, the continuous susceptor automatically follows the movement of the positioning device.

Preferably, the positioning device has the shape of a cone.

Preferably, the shaping device has the shape of a cone, for example embodied as garniture tongue.

Preferably, the positioning device is arranged in the cone of the shaping device.

To simplify insertion of the continuous susceptor in the sheet material or to reduce an insertion resistance, the shaping device may comprise a channel former for forming a channel in partially gathered continuous sheet material. The continuous susceptor may then be inserted into the channel.

A crimping device may provide a sheet material with various kind of crimps. Preferred crimps extend in a longitudinal or transverse direction of a crimped sheet material. Since the crimping of sheet material is often used to support a later gathering of the sheet material, a sheet material is preferably crimped in longitudinal or transport direction.

Preferably, the crimping device is adapted to provide the continuous sheet material with longitudinally running crimps. The longitudinally running crimps are arranged in transport direction of the sheet material. The further downstream arranged gathering process, which is a gathering of the flat sheet material mainly from both lateral sides, may follow along crimps and lead to a more defined gathering and a accordingly to a homogeneously gathered rod.

The crimping device may comprise two interacting crimping elements. The crimping elements are arranged to allow the continuous sheet material to pass in between the two interacting crimping elements thereby crimping the continuous sheet material.

Preferably, a crimping depth adjuster is adapted to vary a distance between the two interacting crimping elements. A small distance of the crimping elements enhances a crimping depth of the sheet material, a large distance reduces a crimping depth of the sheet material.

Preferably, the two interacting crimping elements are crimping plates or crimping rollers.

Preferably, the crimping elements are interlocking crimping elements preferably comprising interlocking crimping structures.

Preferable, the control unit further comprises a moisture sensor for measuring a moisture of the continuous sheet material. It has been found that several parameters may influence a crimping depth of the sheet material. While sheet thickness only has a minor effect on a crimping depth, moisture content of the sheet material may significantly influence the crimping depth. The control unit may be adapted for triggering the crimping depth adjuster to adjust a crimping depth of the sheet material in the crimping device, depending on a moisture content of the continuous sheet material.

The control unit may comprise reference data stored in the control unit. The reference data may comprise information on a crimping behaviour of several kinds sheet material. For example, the reference data may comprise information on physical characteristics on specific compositions of sheet material, such as, for example, tobacco blends used in a tobacco material containing sheet material, at different moisture contents.

A moisture sensor may be arranged at different location along a manufacturing line. Preferably, a moisture sensor is arranged upstream or downstream of the crimping device.

The closed-loop system may further comprise a substance introduction device for introducing a substance to the continuous sheet material.

Preferably, the substance introduction device is a liquid introduction device.

A substance introduced into the continuous sheet material may be a flavour such as for example, menthol, fruit flavour or tobacco flavour. A substance may also be, for example water, nicotine or an aerosol-formers, such as for example glycerin. With the substance introduction device, a sheet material may be adapted to the consumable to be formed. In particular, original characteristics of the sheet material may be changed or adapted to a desired product. For example, by adding humidity, the manufacturing process of the aerosol-forming articles, such as, for example, the crimping process or the susceptor positioning process, may be influenced.

Article comprising different flavours may be manufactured from a same basic sheet material. Yet further, an originally non-aerosol-forming sheet material may be changed into an aerosol-forming sheet material by adding an aerosol-forming substance. While tobacco-based materials already comprise aerosol-forming substances, sheet material made, for example from cellulose-based materials do not.

The closed-loop system may comprise a wrapping device for wrapping the continuous rod with a wrapper. The wrapper may be made of wrapping material as known in the art, for example a wrapping paper or wrapping plastics.

In order to further improve the manufacturing process, the closed-loop system may comprise various controls, for example control sensors. The control system may in particular comprise measurement devices for measuring sheet material parameters before or after the sheet material is crimped, susceptor parameters before the susceptor is inserted into the sheet material, device parameters, such as for example of the crimping device or of a liquid insertion device, or parameters of the formed rod-shaped article.

For example, the control unit may comprise at least a further measurement device for measuring or detecting any one of a

According to another aspect of the present invention, there is provided a method for controlling a position of a susceptor in an aerosol-generating article, the method comprising: