DE102022124016A1 - Method and device for checking a cut surface of a rod-shaped heat-not-burn product in the tobacco processing industry, machine in the tobacco processing industry and use - Google Patents

Abstract

The invention relates to a method and a device for checking cut surfaces of rod-shaped tobacco sticks (10) of heat-not-burn products (20) in the tobacco processing industry, which are partially or completely penetrated along their longitudinal axis by an inductively heatable metal thread (14). . The invention further relates to a machine in the tobacco processing industry and to a use. According to the invention, at least one thermal imaging camera (64a, 64b) is used to check the cut surfaces of the rod-shaped tobacco sticks (10) of heat-not-burn products (20). whether cut edges of the inductively heatable metal thread (14) conform to a predetermined or predeterminable specification.

Description

In the tobacco processing industry, modern rod-shaped heat-not-burn products are manufactured from several rod-shaped components. An important component is a rod-shaped tobacco stick, which has a metal thread running through it along its longitudinal extent, usually along its entire length, which can be heated inductively in a smoking device. The heating of the metal thread is dosed in such a way that the tobacco material surrounding the metal thread emits an aerosol containing nicotine. The temperature remains below the ignition temperature of the tobacco material, so that no harmful combustion products are produced as with conventional cigarettes.

So that the surrounding tobacco material can be heated effectively, such a metal thread has a large specific surface area, i.e. it is narrow in one transverse direction and wide in the other transverse direction. The metal thread therefore forms a flat strip or a flat band. It should also be located as centrally as possible in the tobacco hive.

Such tobacco sticks are usually produced using a rod process. For example, a CLT (Cast Leaf Tobacco) film can be used as the tobacco material, which is crimped and gathered or folded around the centrally arranged metal thread or strip during strand production. The material is then covered with a wrapping material. After the strand forming has been completed, individual tobacco sticks are cut from the strand in a cutting device, i.e. cut off. The cutting edges of the cutting device cut through the entire strand including the metal thread it contains. The applicant produces, among other things, the KDF 2ER strand machine, which carries out this process. A similar procedure is, for example, in WO 2017/184928 A1 described. Other methods use sharpened metal strips that are inserted into the tobacco material with the pointed end. This is for example in WO 2015/176898 A1 described.

Checking the quality of the tobacco sticks includes checking the cut edges. With the metal thread-encrusted tobacco sticks of the Heat-not-Burn products, special attention is paid to the condition and position of the metal thread in the tobacco stick. Since it has already completely passed through the tobacco rod, it is visible at the cut edges and can therefore be visually checked. The applicant sells an optical camera and light source-based testing system known as ICPS - CS, with which the cut edges of the tobacco sticks, which are well illuminated using white light, are recorded two-dimensionally in visible light and automatically evaluated using conventional image analysis algorithms. In some cases, there are problems with detecting the metal thread and the resulting ejection of good products. In particular, in some cases it happens that the system does not detect the metal thread across its entire width, even though the thread can be seen with the naked eye in the images taken by ICPS-CS as being present and not damaged or obscured. Incomplete detection of the metal thread leads to the rejection of good products.

In contrast, the present invention is based on the object of improving the inspection of tobacco sticks covered with a metal thread or rod-shaped heat-not-burn products made therefrom, in particular of reducing the rejection rate for tobacco sticks or products that conform to the specification.

This task is solved by a method for checking cut surfaces of rod-shaped tobacco sticks of heat-not-burn products from the tobacco processing industry, the tobacco sticks being partially or completely penetrated along their longitudinal axis by an inductively heatable metal thread, the cut tobacco sticks being along a Conveying paths are conveyed transversely axially one behind the other past at least one thermal imaging camera, which record two-dimensional thermal images of thermal radiation emitted from the cut surfaces of the tobacco sticks, the thermal images then being evaluated to determine whether cut edges of the inductively heatable metal thread appear in the respective thermal image in accordance with a predetermined or predeterminable specification.

The method according to the invention can be used alone or in addition to existing testing devices such as the applicant's ICPS - CS. In contrast to conventional optical, including infrared-optical, inspection systems, external lighting is not required when taking thermal images. Rather, the heat radiation emitted by the tobacco material and the metal thread at the cutting edge itself is absorbed. The metal strip stands out clearly from the surrounding tobacco material in the thermal image and contrasts much more strongly with the tobacco material than would be the case with a conventional optical inspection under external illumination with visible or infrared light.

This increased contrast results from two factors. On the one hand, the metal thread can differ in temperature from the surrounding tobacco material during production. This means that the metal thread heats up when it is cut to length the friction with the cutting edges of the cutting device is greater than the surrounding tobacco material. In addition, the metal thread can also be brought to an elevated temperature in other ways.

The second factor is that the metal thread has a significantly lower emissivity than the tobacco material. Despite the similar temperature, the metal is therefore recognized as significantly cooler than the tobacco material.

The actual contrast in the thermal image depends on both factors, the temperature difference and the difference in emissivity. This is taken into account when selecting the location along the conveyor path where the thermal images are taken, as well as additional heating of the metal strip if necessary.

The metal threads in the tobacco sticks are therefore inductively heated in further developments of the method along part of the conveying path of the tobacco sticks, in particular a heating is or is set that creates a sufficient contrast to the surrounding tobacco material in the thermal image and also remains below a temperature at which the Surrounding tobacco material begins to emit aerosols.

The heat radiation from the cut surface of the tobacco sticks can be superimposed by intense external heat sources, whose heat radiation is partially reflected on the cut surface. Since this can greatly affect the contrast, embodiments of the method provide for interference radiation to be suppressed, in particular by shielding external heat sources and/or by cooling components in the environment or in the field of view of the at least one thermal imaging camera.

In embodiments, both cut surfaces of the tobacco sticks are checked using at least two thermal imaging cameras at opposite ends of the tobacco sticks being conveyed past. This checks the complete integrity of the metal strip in the tobacco stick.

In various embodiments, the thermal images are recorded shortly after the tobacco sticks have been cut to length from an endless tobacco rod on an insertion drum or downstream in the conveying direction on a trough conveyor device, in particular a trough conveyor drum. The insertion drum is the first drum into which the tobacco sticks, which have been conveyed along the longitudinal axis, are inserted immediately after they have been cut to length from the endless strand. The insertion drum transfers the tobacco sticks from a longitudinal to a transverse axial conveyance. The thermal images can be recorded at any suitable point on the machine during the transverse axial conveyance of the tobacco sticks or the products with the tobacco sticks, where a cut edge of the tobacco sticks is freely visible to a thermal imaging camera.

In embodiments, the predefined or predefinable specification includes information on the length of the cut edge of the metal thread, the minimum distance between the ends of the cut edges of the metal thread and the outer edge of the tobacco stick, the orientation of the cut edge of the metal thread and/or a degree of deflection of the cut edge of the metal thread. Furthermore, in embodiments, tobacco sticks in which no metal thread or no metal thread conforming to the specification is detected in the thermal image, or heat-not-burn products with such tobacco sticks, are excluded from further processing.

In a further development, together with the thermal images, additional camera recordings in visible light, in particular in black and white, grayscale or colors, are evaluated with regard to the cutting edge of the inductively heatable metal thread or the cutting surface of the rod-shaped tobacco stick. An example of an evaluation in visible light is the applicant's ICPS-CS system. The joint evaluation can be carried out, for example, by both systems carrying out separate evaluations, the results of which produce probabilities or other criteria for a defective or defect-free product, which are then offset against each other in order to arrive at a consolidated probability for a defective or defect-free product. Alternatively, it is also possible to combine the thermal images and images in visible light for the cut surfaces of the individual products into a composite image after geometric adjustment and to evaluate this.

The object on which the invention is based is also achieved by a device for checking cut surfaces of rod-shaped tobacco sticks of heat-not-burn products from the tobacco processing industry, which are partially or completely penetrated along their longitudinal axis by an inductively heatable metal thread, which has a conveyor device , a testing device and an evaluation device, wherein the conveying device is set up to convey the rod-shaped tobacco sticks or rod-shaped heat-not-burn products with such tobacco sticks in a transverse axial orientation, the testing device being arranged on the conveying device and oriented so that it takes two-dimensional images of the frontal cut surfaces of tobacco sticks conveyed past, the evaluation device being designed to evaluate images of the cut surfaces th, whether cut edges of the inductively heatable metal thread emerge in the respective recording in accordance with a predetermined or predeterminable specification, characterized in that the testing device comprises at least one thermal imaging camera in order to record two-dimensional thermal images of thermal radiation emitted by the cut surfaces of the tobacco sticks.

Due to its equipment and functionality, this device is set up to carry out the method according to the invention described above and realizes the same advantages, properties and features.

In embodiments, an inductive heating device is included along a conveying path of the tobacco sticks upstream of the at least one thermal imaging camera, which is set up to inductively heat metal threads in the tobacco sticks.

To suppress interference radiation, in embodiments a shielding of external heat sources and/or cooling of components in the environment or in the field of view of the at least one thermal imaging camera is/are included.

In order to achieve a complete inspection of the tobacco sticks, in embodiments at least two thermal imaging cameras are arranged at opposite ends of the tobacco sticks conveyed past in order to check both cut surfaces of the tobacco sticks.

In further developments, there is a reject device which is set up to exclude from further processing those tobacco sticks in which no metal thread or no metal thread that conforms to the specification is detected in the thermal image, or heat-not-burn products with such tobacco sticks.

The object on which the invention is based is also achieved by a machine in the tobacco processing industry with a previously described device according to the invention. The machine realizes the same features, properties and advantages as the method and device according to the invention.

In one embodiment of the machine, the conveying device of the device is designed as an insertion drum, as a cutting drum or as a trough conveyor device, in particular a trough conveyor drum, which is arranged downstream of the insertion drum or cutting drum in the conveying direction.

In a further development, the testing device additionally comprises a camera in visible light in order to record two-dimensional black-and-white, gray-scale or color images of one of the cut surfaces of the tobacco sticks, the evaluation device being designed to record the two-dimensional black-and-white, gray-scale or color images together with the thermal images with respect to the Evaluate the cutting edge of the inductively heatable metal thread. Example alternatives to such a joint evaluation have been described in connection with the method and concern, among other things, adding up the probabilities or other criteria for defective or defect-free products calculated separately based on the thermal images and the visible light images, or the creation and evaluation of composite images Thermal images and images in visible light.

The object on which the invention is based is also achieved by using at least one thermal imaging camera for checking cut surfaces of rod-shaped tobacco sticks of heat-not-burn products from the tobacco processing industry, which are penetrated along their longitudinal axis by an inductively heatable metal thread, to see whether there are cut edges of the inductively heatable metal thread conform to a predetermined or predeterminable specification. The use also realizes the same features, properties and advantages as the other subject matter of the invention.

Further features of the invention can be seen from the description of embodiments of the invention together with the claims and the accompanying drawings. Embodiments according to the invention can fulfill individual features or a combination of several features.

Within the scope of the invention, features marked “in particular” or “preferably” are to be understood as optional features.

• 1 eine Draufsicht auf eine Schnittfläche eines Tabakstocks,
• 2 einen Querschnitt durch ein stabförmiges Heat-not-Burn-Produkt,
• 3 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung,
• 4 eine Darstellung eines erfindungsgemäßen Verfahrens und
• 5 eine schematische Darstellung einer Ausführungsform einer erfindungsgemäßen Vorrichtung.

The invention is described below without limiting the general idea of the invention using exemplary embodiments with reference to the drawings, with express reference being made to the drawings with regard to all details of the invention not explained in more detail in the text. Show it:

• 1 a top view of a cut surface of a tobacco stick,
• 2 a cross section through a rod-shaped heat-not-burn product,
• 3 a schematic representation of a device according to the invention,
• 4 a representation of a method according to the invention and
• 5 a schematic representation of an embodiment of a device according to the invention.

In the drawings, the same or similar elements and/or parts are provided with the same reference numbers, so that they are not presented again.

1 shows a top view of a cut surface of a tobacco stick 10, as presented to the applicant's ICPS-CS system or the thermal imaging camera used according to the invention. The cut surface reveals the cut edge of a centrally located metal thread 14 embedded in a tobacco material 12, which in turn is covered by a wrapping material 16. The tobacco material is, for example, a CLT (Cast Leaf Tobacco) film that has been crimped and gathered or folded around the centrally arranged metal thread 14 during strand production. The metal thread 14 is flat in cross section, has a width between 1 mm and 5 mm and a thickness between 0.01 mm and 2 mm.

The metal thread 14 is placed essentially centrally in the tobacco stick 10 and has a slightly curved cross-sectional shape due to processing, in particular cutting to length. The ends or edges of the metal thread 14 are at a sufficient distance from the wrapping material 16, i.e. H. the outer edge of the tobacco stick 10.

Error patterns may, for example, appear such that the distances between the metal thread 14 and the outer edge of the tobacco stick 10 are not large enough, that the bending of the cross-sectional profile of the metal thread 14 is too strong compared to product specifications, or that part of the metal thread 14 is missing. Such non-specification tobacco sticks 10 or heat-not-burn products made from them must be excluded from further production.

In 2 shows a cross section in the longitudinal axial direction through an exemplary rod-shaped heat-not-burn product 20. This comprises several elements, which are each cylindrical or star-shaped and are put together to form a long rod-shaped product, which are covered and held together by means of a wrapping material 22 become. To the tobacco stick 10, which is already in 1 has been described, a support element 30, a cooling element 40 and a filter element 50 follow downstream.

The support element 30, which includes a mechanically stable hollow cylinder 32 with an inner cylindrical cavity 34, ensures that the tobacco stick 10 remains at the distal end of the heat-not-burn product 20. It also serves as a spacer to create a distance from the cooling element 40, which serves to cool the aerosol emanating from the tobacco stick 10. The cooling element 40 can contain a cooling material 42 encased in a wrapping material 44, for example a crimped and gathered film made of a polylactide. This film has a large number of channels extending longitudinally axially to align the product, which have a large specific surface area for cooling the aerosols.

At the mouth end, i.e. the proximal end, the cooling element 40 is adjoined by a filter element 50, which can be a conventional acetate filter. The materials mentioned here for the various elements of the product are to be understood as examples.

Conventional optical testing methods, in which the cut surface of each tobacco stick 10 is illuminated with bright white light and the reflected light is captured by an optical camera and the captured images are then evaluated with regard to the optical appearance of the metal thread 14 in tobacco material 12, suffer from a relatively low level Contrast between the metal thread 14 and the tobacco material 12, which leads to tobacco sticks 14 being recognized as defective in some cases by the automatic image processing, even though they actually have no defect.

According to the present invention, the cut surface or surfaces of the tobacco sticks 10 are scanned using thermal imaging cameras. A device 60 according to the invention is in 3 shown schematically. This includes a conveyor device 62, for example a trough drum or a trough conveyor belt, in the troughs of which tobacco sticks 10 are held and conveyed transversely axially in the conveying direction 63a along a conveyor path 63. In the embodiment shown here, both cut surfaces 11a, 11b are visible from the respective side. The tobacco sticks 10 are conveyed through the viewing area of a conveyor device 62, which in this exemplary embodiment comprises two thermal imaging cameras 64a, 64b, each of which takes a thermal image of the opposite cut edges 11a, 11b. These are forwarded via data lines 66a, 66b to an evaluation device 68, which carries out automated image processing on the thermal images, in which the thermal images are examined to determine whether the metal thread 14 is present in them as specified. If this is not the case, the evaluation device 68 outputs a signal to an output (not shown). Shooting device downstream, which shoots out the defective tobacco sticks 10 and thus removes them from further processing.

This in 3 The example shown represents the special case of checking the tobacco stick 10. In the case of checking the cut surfaces of the tobacco stick 10 in the complete heat-not-burn product 20 according to 2 This check is only possible from one side. Even if the thermal image inspection takes place on the bare tobacco stick 10, it may be sufficient to do this from one side, since the cut surface 11a of a tobacco stick 10 corresponds to the opposite cut surface 11b of the previous or subsequent tobacco stick 10 or resulted from the same cutting process .

In 4 Finally, a method according to the invention is shown with its successive process steps. First, a strand is formed from a tobacco material 12, which is placed around a continuous metal thread 14 and covered with a wrapping material 16 (step S101). Individual tobacco sticks 10 are cut to length from this endless strand in a cutting device (step S102). The tobacco sticks 10 that have so far been conveyed longitudinally axially are brought into a transverse axial order and further conveyed transversely axially, for example by means of an insertion drum (step S103). Optionally, the metal thread 14 in each tobacco stick 10 can be heated in an inductive heating section (step S104) in order to produce a desired contrast in the subsequently recorded thermal images (step S105) between the metal threads 14 and the surrounding tobacco material 12.

In the subsequent automatic image processing (step S106), each thermal image is examined to determine whether a metal thread 14 appears in the thermal image and whether the metal thread 14 corresponds to the specifications specified for it. Subsequently, a tobacco stick 10 that was recognized as out of specification is ejected from further processing (step S107).

5 schematically represents an embodiment of a device according to the invention, which has a, for example inductive, heating device 70 for the metal threads 14, a testing device 64 with one or more thermal imaging cameras and a reject device 72, lined up one behind the other on the conveying path 63 in the conveying direction 63a. The latter is controlled by an evaluation device 68, which evaluates the thermal images transmitted by the testing device and sends a reject signal to the reject device 72 if tobacco rods 10 were recognized as not conforming to the specification.

All of the features mentioned, including those that can be seen from the drawings alone as well as individual features that are disclosed in combination with other features, are viewed alone and in combination as essential to the invention. Embodiments according to the invention can be fulfilled by individual features or a combination of several features.

Reference symbol list

10

tobacco stick

11a, 11b

cutting surface

12

tobacco material

14

metal thread

16

wrapping material

20

Heat-not-burn product

22

wrapping material

30

Support element

32

Hollow cylinder

34

cavity

40

Cooling element

42

Cooling material

44

Cover material

50

Filter element

60

contraption

62

Conveyor device

63

conveying route

63a

Direction of conveyance

64

Testing device

64a, 64b

Thermal camera

66a, 66b

Data line

68

Evaluation device

70

Heating device

72

Reject device

S101

strand formation

S102

Cutting tobacco sticks to length

S103

Transition to cross-axial conveying

S104

optionally heating the metal threads

S105

Taking thermal images of the cut surfaces

S106

automatic image processing

S107

Rejecting out-of-spec tobacco sticks

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2017184928 A1 [0003]
• WO 2015176898 A1 [0003]

Claims (17)

Method for checking cut surfaces of rod-shaped tobacco sticks (10) of heat-not-burn products (20) of the tobacco processing industry, which are partially or completely penetrated along their longitudinal axis by an inductively heatable metal thread (14), the cut tobacco sticks (10 ) are conveyed transversely axially one behind the other along a conveyor path (63) past at least one thermal imaging camera (64a, 64b), which record two-dimensional thermal images of thermal radiation emitted by the cut surfaces of the tobacco sticks (10), the thermal images then being evaluated to determine whether cut edges of the inductive Heatable metal thread (14) emerges in the respective thermal image in accordance with a predetermined or predeterminable specification. Procedure according to Claim 1 , characterized in that the metal threads (14) in the tobacco sticks (10) are inductively heated along part of the conveying path (63) of the tobacco sticks (10), in particular heating being or being set which provides a sufficient contrast to the surrounding tobacco material ( 12) and remains below a temperature at which the surrounding tobacco material (12) begins to secrete aerosols. Procedure according to Claim 1 or 2 , characterized in that interference radiation is suppressed, in particular by shielding external heat sources and/or by cooling components in the environment or in the field of view of the at least one thermal imaging camera (64a, 64b). Procedure according to one of the Claims 1 until 3 , characterized in that both cut surfaces of the tobacco sticks (10) are checked with at least two thermal imaging cameras (64a, 64b) at opposite ends of the tobacco sticks (10) conveyed past. Procedure according to one of the Claims 1 until 4 , characterized in that the thermal images are recorded shortly after the tobacco sticks (10) have been cut to length from an endless tobacco rod on an insertion drum or downstream in the conveying direction (63a) on a trough conveyor device, in particular trough conveyor drum. Procedure according to one of the Claims 1 until 5 , characterized in that the predetermined or predeterminable specification includes information on the length of the cut edge of the metal thread (14), the minimum distance between the ends of the cut edges of the metal thread (14) and the outer edge of the tobacco stick, and the orientation of the cut edge of the metal thread (14). and/or to a degree of deflection of the cutting edge of the metal thread (14). Procedure according to one of the Claims 1 until 6 , characterized in that such tobacco sticks (10) in which no metal thread (14) or no specification-compliant metal thread (14) is recognized in the thermal image, or heat-not-burn products (20) with such tobacco sticks (10), from which further processing can be excluded. Procedure according to one of the Claims 1 until 7 , characterized in that together with the thermal images, additional camera recordings in visible light, in particular in black and white, grayscale or colors, are evaluated with respect to the cutting edge of the inductively heatable metal thread (14) or the cutting surface of the rod-shaped tobacco stick (10). Device (60) for checking cut surfaces of rod-shaped tobacco sticks (10) of heat-not-burn products (20) of the tobacco processing industry, which are partially or completely penetrated along their longitudinal axis by an inductively heatable metal thread (14), comprising a conveyor device (62), a testing device (64) and an evaluation device (68), the conveying device (62) being set up to transport the rod-shaped tobacco sticks (10) or rod-shaped heat-not-burn products (20) with such tobacco sticks (10). transverse-axial alignment, the testing device (64) being arranged on the conveying device (62) and being oriented in such a way that it takes two-dimensional images of the frontal cut surfaces of tobacco sticks (10) conveyed past, the evaluation device (68) being designed to take images of the cut surfaces to evaluate whether cut edges of the inductively heatable metal thread (14) emerge in the respective receptacle in conformity with a predetermined or predeterminable specification, characterized in that the testing device (64) comprises at least one thermal imaging camera (64a, 64b) in order to produce two-dimensional thermal images of one of the cut surfaces to absorb the heat radiation emitted by the tobacco sticks. Device (60) after Claim 9 , characterized in that an inductive heating device (70) is included along a conveying path (63) of the tobacco sticks (10) upstream of the at least one thermal imaging camera (64a, 64b), which is set up to inductively detect metal threads (14) in the tobacco sticks (10). to heat up. Device (60) after Claim 9 or 10 , characterized in that for suppression from interference radiation, a shielding from external heat sources and / or a cooling of components in the environment or in the field of view of the at least one thermal imaging camera (64a, 64b) is or are included. Device (60) according to one of Claims 9 until 11 , characterized in that at least two thermal imaging cameras (64a, 64b) are arranged at opposite ends of the tobacco sticks (10) conveyed past in order to check both cut surfaces of the tobacco sticks (10). Device (60) according to one of Claims 9 until 12 , characterized in that there is a reject device (72) which is set up to remove tobacco sticks (10) in which no metal thread (14) or no specification-compliant metal thread (14) is detected in the thermal image, or heat-not-burn products (20) with such tobacco sticks (10) to exclude from further processing. Machine for the tobacco processing industry with a device (60) according to one of the Claims 9 until 13 . machine after Claim 14 , characterized in that the conveying device (62) of the device (60) is designed as an insertion drum, as a cutting drum or as a trough conveyor device, in particular a trough conveyor drum, arranged downstream of the insertion drum or cutting drum in the conveying direction (63a). machine after Claim 14 or 15 , characterized in that the testing device additionally comprises a camera in visible light in order to record two-dimensional black-and-white, gray-scale or color images of one of the cut surfaces of the tobacco sticks, the evaluation device (68) being designed to take the two-dimensional black-and-white, gray-scale or color images together with the thermal images regarding the cutting edge of the inductively heatable metal thread (14). Use of at least one thermal imaging camera (64a, 64b) for checking cut surfaces of rod-shaped tobacco sticks (10) of heat-not-burn products (20) in the tobacco processing industry, the tobacco sticks (10) being supported along their longitudinal axis by an inductively heatable metal thread (14 ) are interspersed, depending on whether cut edges of the inductively heatable metal thread (14) conform to a predetermined or predeterminable specification.

Images