EP2769632B2 - Measurement method and measurement assembly for detecting the position of an object in a filter rod conveyed along the longitudinal axis, and machine for the tobacco processing industry - Google Patents

Description

The invention relates to a measuring method for detecting the position of an object, in particular a capsule-shaped object, in a filter train in the tobacco processing industry that is conveyed along the longitudinal axis. The invention also relates to a corresponding measuring arrangement and a machine in the tobacco processing industry.

In the tobacco and cigarette filter processing industry, capsules containing special aromas, mostly in liquid form, are increasingly being introduced into the filter material. The capsules can be crushed by the consumer immediately before consumption in order to release the aromatic substances in a targeted and fresh manner into the filter. For example, one capsule per filter is automatically inserted into the filter rod of a production machine using an insertion device.

It is known in the prior art to check the presence and the cycle-related position of the capsules in the axial or strand direction. On the one hand, the exact position in the axial or strand direction is important for the further processing of the product, so that, for example, any laser perforation on the finished product does not damage the capsule. Furthermore, the wrapping paper of the end product usually has a marking of the capsule position in order to make it easier for the consumer to crush the capsule, which is then no longer visible. The capsule should then always be exactly below the mark in the axial direction.

the WO 2009/099793 A2 discloses a measuring device for determining the condition of an object in a filter rod of a filter rod manufacturing machine. The condition to be determined includes, for example, the absence of an object, incorrect arrangement or defective object. The measuring device can have, for example, a microwave sensor, a beta radiation sensor, an infrared sensor or an X-ray sensor.

From the DE 10 2009 017 963 A1 a microwave measuring device for determining the position of the capsule in the longitudinal axial direction of the rod in a filter rod machine is known. Depending on the measurement signal, the rotational speed of a capsule insertion wheel or a cutting device for cutting the filter rod into filter rods can be controlled.

If the capsule position deviates perpendicularly to the strand axis, i.e. if the capsule is not in the middle of the filter material, the capsule can be damaged or destroyed, especially in further processing. For example, a filter with a capsule in a cigarette manufacturing machine is subject to different forces, e.g. during the rolling process with a starting bar. If the capsule is damaged or destroyed, the flavoring is released in an uncontrolled manner and the desired controlled release by the consumer of the end product is no longer possible. So far, attempts have been made with great design effort to avoid mechanical stress on the capsule, which is not always in the middle, from the outset, for example by means of undercuts, avoidance of guides in the vicinity of the capsule, etc. However, these efforts are subject to design limits.

WO 2011/083406 A2 discloses a measuring method for detecting an object in a longitudinally axially conveyed filter rod in the tobacco processing industry, the filter rod being irradiated on the casing side along at least three optical axes which are mutually independent of one another.

EP 1 557 100 A1 discloses a device for testing a filter rod in the tobacco processing industry using the transmitted light method, the light propagating in the filter rod in a conical manner as a result of scattering in the filter material of the filter rod.

U.S. 4,986,285 discloses a method for determining the density of tobacco material in a tobacco rod by means of transmission of infrared light along three independent optical axes.

The invention is based on the object of providing a measuring method and a measuring arrangement in which the probability of damage to the object during filter production or processing and thus of a defective end product can be reduced.

The invention solves this problem with the features of the independent claims. The position of the object can be determined easily and with high accuracy in two directions perpendicular to the axis of the filter rod due to the radiation through the filter rod on the casing side by means of at least three optical axes which are mutually independent of one another. On the basis of the determined position of the object, different suitable measures can be taken in order to be able to prevent damage to the inserted object during further processing. Elaborate structural measures to avoid mechanical stress on an object that is not located in the center are unnecessary due to the invention. Finally, the use of an optical measuring device is generally less complex and therefore considerably more cost-effective than the microwave measuring devices used in the prior art. If the position of the object in the direction of the strand is advantageously also determined from the measurement signals, maximum position information is available in all three spatial directions.

The object can in particular be a hollow object and filled with an in particular liquid aroma substance. These are preferably discrete objects, ie objects that are not continuous in the strand direction and are arranged at a regular axial distance from one another, in particular capsules or spheres. However, the application of the invention for a continuous object such as, for example, a thread impregnated with flavoring substance is not ruled out in principle.

The optical measuring device preferably works in the visible wavelength range and/or in the infrared range. An ultraviolet measuring device is also conceivable.

The optical axes of the measuring device preferably enclose an angle of at least 30°, more preferably at least 45°, with one another, as a result of which the accuracy of the position determination can be increased. The optical axes are particularly advantageously arranged at equal angular distances around the filter rod. Each optical axis is expediently assigned a single-axis measuring device with a light source and a sensor. The light source and sensor of each measuring device are preferably arranged on opposite sides of the filter rod. The measuring devices therefore work advantageously using the radiographic method. The number of optical axes is particularly advantageously three, as a result of which the invention is implemented with a minimum of effort.

Various advantageous measures can be taken on the basis of the determined position of the object. A deviation of the determined position from a target position is preferably determined. This enables an advantageous good/bad evaluation of the position of the object based on a comparison of the determined deviation with a preferably adjustable threshold value.

According to the invention, a position signal containing information on the determined position of the objects is automatically and continuously provided in a filter production or filter processing machine. The position signal is preferably provided in a cycle-related manner relative to the cycle of a machine in the tobacco processing industry.

On the basis of the position signal, a device for inserting the objects into the filter rod is controlled and/or regulated according to the invention. In particular, the two-dimensional position of the inserted object can advantageously also be adjusted or controlled perpendicularly to the line axis, with the actual value of the position measured by the measuring device corresponding to the generally central setpoint value of the position in the filter line. This was not previously known in the prior art. Of course, the axial position of the object can also be adjusted or regulated.

In one embodiment, the clock-related position signal can advantageously be used to eject filter elements with an incorrect object position. In general, the position information can advantageously be displayed on an operator terminal of a filter-processing machine.

Fig. 1

eine schematische Ansicht einer Filterstab-Herstellungsmaschine;

Fig. 2

eine Querschnittsansicht einer optischen Messvorrichtung; und

Fig. 3, 4

Kurvendiagramme der Messintensität bei einer mittig und einer exzentrisch in einem Filterstrang liegenden Kapsel.

The invention is explained below on the basis of preferred embodiments with reference to the accompanying figures. It shows:

1

a schematic view of a filter rod manufacturing machine;

2

a cross-sectional view of an optical measuring device; and

Figures 3, 4

Curve diagrams of the measuring intensity with a capsule lying in the middle and an eccentric one in a filter rod.

The filter rod manufacturing machine 10 according to FIG figure 1 comprises a filter tow processing unit 120 and a subsequent filter rod machine 140. In the processing unit 120, a filter tow strip 61 is stretched after being pulled off the filter tow bale 110, spread out and sprayed with a plasticizer, for example triacetin. The strip of material 61 prepared in this way is subsequently fed to the filter rod machine 140 , in particular through an inlet funnel 141 . A format device 53 is provided in the filter rod machine 140, which forms a filter rod 40 from the filter tow strip 61 by wrapping it with a wrapping strip (not shown) drawn off a bobbin.

An insertion device 42 for inserting capsules filled with flavoring substance and removed from a reservoir 12 into the material strip 61 is arranged between the inlet hopper 141 and the format device 53 . The insertion device 42 can be designed in different ways, for example as an insertion wheel, insertion finger, or in some other suitable way. The insertion device 42 is preferably adjustable with regard to the axial position and the position of the capsules perpendicular thereto in the filter rod. In particular, the insertion device 42 can be controlled by an electronic control unit 13 with regard to the axial and perpendicular position of the capsules in the filter rod.

In other embodiments, the insertion device 42 is arranged in the filter tow processing unit 120 .

The filter rod 40 is cut into filter rods 41 by means of a cutting device 46, which usually have a multiple, for example double, useful length. One capsule is usually provided for each filter element corresponding to a cigarette. Following the cutting device 46, a reject device 51 can be provided, which is set up to remove individual filter rods 41 identified as defective from the filter flow, for example by means of compressed air. After leaving the filter rod machine 140, the filter rods 41 are temporarily stored or fed to subsequent processing, for example in a cigarette manufacturing machine.

Between the formatting device 53 and the cutting device 46 is an in figure 1 only schematically shown optical measuring device 45 arranged, by means of the two-dimensional position (x, y) perpendicular to the filter rod and preferably also the axial position (z) of the capsules 20 in the filter train 40 is continuously determined. A preferred embodiment of the optical measuring device 45 is explained in more detail below. The measuring device 45 therefore provides a signal with the continuous coordinates of the capsule in the x, y and z directions. The determined position of the capsules is transmitted to the electronic control unit 13 and displayed, for example, on an operator terminal 14 connected to the control unit 13 .

The control unit 13 preferably regulates the insertion device 42 in such a way that the two-dimensional position of the capsules, determined by the measuring device 45, corresponds perpendicularly to the filter rod, in particular to the desired central position. The axial position of the capsules is preferably also regulated to its desired value in a similar manner.

In addition to the regulation of the two-dimensional position of the capsules perpendicular to the filter rod, capsules whose distance from the particularly central target position exceeds a specific threshold value can also be ejected by actuating the reject device 51 .

On the basis of the determined axial position of the capsules in the filter rod, the cutting device 46 can also be controlled or regulated in such a way that the axial position of the capsule in the individual filter element corresponds to the desired axial position.

A preferred embodiment of the optical measuring device 45 is in figure 2 shown. The measuring device 45 comprises a plurality of here three measuring devices 15, 15', 15". Each measuring device 15 (15', 15") is preferably a uniaxial measuring device and comprises a light source 16 (16', 16") and a light-sensitive sensor element 17 (17', 17"), which are arranged along an optical axis 18 (18', 18") in such a way that the light from the light source 16 (16', 16") entering the filter rod 40 on the casing side passes through the filter rod, on the casing side exits the filter rod 40 and falls on the light-sensitive sensor element 17 (17', 17"). The light sources 16, 16', 16" can be light-emitting diodes, for example. The light-sensitive sensor elements can be photodiodes or CCD elements, for example. The light sources 16, 16′, 16″ and/or the sensor elements 17, 17′, 17″ can be arranged at a distance from the filter train 40, in which case the optical connection to the filter train 40 can be made in particular by means of light guides. This enables a small design and a flexible arrangement of the measuring device 45. The measuring devices 15, 15', 15'' can work with red light or infrared light, for example.

The measuring devices 15, 15′, 15″ and the optical axes 18, 18′, 18″ are preferably arranged perpendicular to the axis of the strand and advantageously independently of one another, ie they intersect in a view along the axis of the strand as in FIG figure 2 at a non-zero angle of preferably at least 30°, more preferably at least 45°. The measuring devices 15, 15′, 15″ and the optical axes 18, 18′, 18″ are preferably arranged regularly or at equal angular distances, here 60°, relative to one another around the filter rod 40 . The measuring devices 15, 15′, 15″ are in the embodiment according to figure 2 arranged in the same plane, in particular perpendicular to the strand axis. However, this is not necessarily the case; the measuring devices 15, 15', 15" can also be arranged one behind the other in the direction of the rod or at an axial distance from one another or at different axial positions of the filter rod. This can be advantageous in order to avoid unwanted interference between the measuring devices 15 , 15', 15" to prevent.

The wavelength of the measuring devices 15, 15', 15" is advantageously chosen such that the filter material 21, in particular cellulose acetate fibers, and the enveloping strip cause only a slight attenuation of the light emitted by the light sources 16, 16', 16" compared to the capsule 20. The filter material 21 and the wrapping strip are thus essentially translucent or transparent with respect to the measurement wavelength. Each of the measuring devices 15, 15′, 15″ therefore essentially measures the shading of the light emitted by the corresponding light source 16, 16′, 16″ by the capsule 20. When the capsule 20 is in the middle of the filter rod 40, the measuring signal is all Measuring devices 15, 15', 15" are ideally of the same size. If the capsule 20 is not located in the middle of the filter rod 40, the measuring signals of the measuring devices 15, 15', 15" differ from one another. The position of the capsule 20 in the radial direction or in the x/y direction, i.e. in a plane perpendicular to the strand axis (paper plane in figure 2 ), determine quantitatively. The corresponding evaluation of the measurement signals is carried out in the electronic control unit 13 .

The measuring signals are continuously taken from the measuring devices 15, 15′, 15″. Due to the transport of the filter rod 40 in the direction of the rod, there is a time course as shown in FIGS Figures 3 and 4 is reproduced. The curves I, I' and I" represent the measurement intensity of the measurement signals recorded by the light-sensitive sensor elements 17, 17' and 17". Due to the transport in the z-direction, the curves reflect the progression in the z-direction. At time t o , the capsule 20 is in the center of the measuring plane in the direction of the strand. In this position, the measurement intensity is minimal due to the shadowing of the incident light by the capsule 20. By determining to or another characteristic point in time, a position reference in the z-direction related to the machine cycle can be determined. The areas of maximum intensity in the Figures 3 and 4 correspond to the phases between the capsules, where the light falls unhindered through the capsules 20 onto the light-sensitive sensor elements 17, 17' or 17". The duration of the curves in Figures 3 and 4 extends over each slightly more than a capsule length 20.

In figure 3 shows the course of measurement for a capsule 20 that is ideally located in the middle. Here, at time t o , all curves I, I', I" are at the same minimum intensity level. In figure 4 the course of measurement for an eccentric position of the capsule 20 is shown. Here the curves I, I', I" are at different intensity levels at time t o .

The measuring device 45 can also have more than three measuring devices 15, 15', 15", . . . , as a result of which the measuring accuracy can be increased if necessary.

In addition to determining the position of the capsules 20, the measuring device 45 can also perform other functions, for example segment monitoring or control, for example in the case of filter segments of a multi-segment filter having different translucency, and/or gap monitoring.

Claims (12)

1. Measuring method for detecting the position of an in particular capsular object (20) in a longitudinally conveyed filter strand (40) of the tobacco processing industry, wherein radiation is transmitted through the circumferential surface of the filter strand (40) along at least three optical axes (18, 18', 18") located mutually independent of one another, as a result of which at least three independent measuring signals are obtained, and the position of the object (20) is determined in two directions perpendicular to the filter strand (40) through appropriate combination of the measuring signals, wherein the method is a transmittive method, wherein the respective shadowing of the optical radiation passing through the filter strand (40) caused by the object (20) is measured, characterized in that a position signal containing information on the determined position is provided automatically and continuously, wherein a means (42) for inserting the objects (20) into the filter strand (40) is controlled and/or regulated by means of the position signal.
2. Measuring method according to claim 1, characterized in that the deviation of the determined position from a target position is determined.
3. Measuring method according to claim 2, characterized in that a good/bad evaluation of the position of the object (20) is performed on the basis of a comparison of the determined deviation with a threshold.
4. Measuring method according to any one of the preceding claims, characterized in that the provision of the position signal is cycle-related relative to the work cycle of an apparatus (140) of the tobacco processing industry.
5. Measuring method according to claim 4, characterized in that the position signal is used to discharge filter elements (41) with incorrect object position.
6. Measuring method according to one of the preceding claims, characterized in that the position information is displayed on an operation terminal (14) of a filter processing apparatus (10).
7. Measuring arrangement comprising a measuring device (45) for detecting the position of an object (20) in a longitudinally conveyed filter strand (40) of the tobacco processing industry and an electronic control unit (13) for evaluating the measuring signals transmitted by the measuring device (45), wherein the measuring device (45) is configured to transmit radiation through the circumferential surface of the filter strand (40) along at least three optical axes (18, 18', 18") located mutually independent of one another, and to generate at least three corresponding independent measuring signals, and wherein the electronic control unit (13) is configured to determine the position of the object (20) in a plane perpendicular to the filter strand (40) through appropriate combination of the measuring signals, wherein the measuring device (45) is configured to measure the respective shadowing of the optical radiation passing through the filter strand (40) caused by the object (20), characterized in that the electronic control unit (13) is configured to control and/or regulate a means (42) for inserting the objects (20) into the filter strand (40) by means of a position signal provided automatically and continuously and containing information on the determined position.
8. Measuring arrangement according to claim 7, characterized in that the optical axes (18, 18', 18") of the measuring device (45) mutually form an angle of at least 30° between them.
9. Measuring arrangement according to one of the claims 7 or 8, characterized in that the optical axes (18, 18', 18") are located at regular angular distances around the filter strand (40).
10. Measuring arrangement according to one of the claims 7 to 9, characterized in that one measuring means (15, 15', 15") comprising a light source (16, 16', 16") and a light-sensitive sensor element (17, 17', 17") which are arranged in particular on opposite sides of the filter strand (40) is allocated to each optical axis (18, 18', 18").
11. Measuring arrangement according to one of the claims 7 to 10, characterized in that the number of optical axes (18, 18', 18") or of optical measuring means (15, 15', 15") is three.
12. Apparatus of the tobacco processing industry, in particular filter strand apparatus (140), characterized in that the apparatus includes a measuring arrangement according to one of the claims 7 to 11.

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