KR20210080305A - Detection system - Google Patents

Abstract

The present invention relates to a system which evaluates a possibility to permit when a product filter rod including a core extended in a longitudinal direction of filtering materials, filter, or filter element moves along a predefined path. The system comprises an image capture device (404) configured to capture a plurality of images of at least a part of a surface extended in a longitudinal direction of an imaging area (403) when the filter rod, filter, or filter element passes through the imaging area (403). A processing unit (408) is provided to receive image data from the image capture device, and is configured to identify a defect in the filtering materials for each captured image. In addition, a rolling mechanism (405) is provided to roll when the filter rod, filter, or filter element passes through the imaging area. The present invention is able to automatically inspect a longitudinal external surface of the filter rod, filter, or filter element by rolling the filter rod when the filter rod passes through the imaging area.

Description

Detection system {DETECTION SYSTEM}

The present invention relates to a system for evaluating the quality and acceptability of a product filter or filter element of a product filter or filter element, for example as part of a filter manufacturing process.

Conventional filtering materials used in tobacco filters are formed as continuous tows of filamentary cellulose acetate, which are brought together in rods to form a filter, or filter element, having a generally cylindrical structure.

The manufacture of tobacco filters, or related products, having a cylindrical structure is well known in the art. Such filters typically comprise a longitudinally extending generally cylindrical core of tobacco smoke filtering material, optionally with a wrapper. They may be self-supporting (eg unwrapped acetate, or NWA), or may require a wrapper or plugwrap.

1 shows one end (downstream or mouth end) of an example of a filter element. The filter element comprises a thermoformed longitudinally extending core 1 of filtering material of substantially circular cross-section; A typical filter element or rod may have a perimeter, for example in the range of 14 to 28 mm. The longitudinally extending core 1 is made by thermoforming a plasticised cellulose acetate fibrous tow. Filters made of different materials, such as paper, may be used. The filtering material may consist of one or more different segments. For example, a filter element may be coupled to or adjacent to another filter element (not shown in FIG. 1 ) at its upstream end and an adjacent filter element wrapped with a plugwrap to form a dual filter as is well known in the art. have. A dual filter comprising a filter element engages a wrapped tobacco rod at its upstream end, for example using a full tipping overwrap that wraps and binds the entire length of the dual filter and only the proximal end of the wrapped tobacco rod. may be used to form filter cigarettes.

It is possible for imperfections or defects to be incorporated in the filter material and in particular on the outer surface of the filter. It is advantageous to ensure that such defective filters are not supplied to the customer, and that any errors in production that cause imperfections may be quickly filtered out as production is stopped.

To date, there are no simple automated techniques available for monitoring visual properties across the outer surface of a filter. Instead, visual quality checks will be performed in a fixed order by skilled personnel after filter production. Obviously, this is time consuming and expensive and depends on the operator involved. Furthermore, if the error is common to a large number of product filters, it may be due to a problem in the manufacturing process; Monitoring product quality after production does not account for stopping production if there is a problem with the process. Accordingly, there is a need for a visual inspection system that can be easily integrated "in the production line" as part of a rapid, accurate, reliable and high-speed filter production process for generally cylindrically shaped filters.

The invention is defined in the independent claims, to which reference is now made. Preferred features are stated in the dependent claims.

According to one embodiment of the present invention, there is provided a system for evaluating the acceptability of a product filter rod, filter or filter element comprising a longitudinally extending core of filtering material as it travels along a predefined path. The system includes an image capture device configured to capture a plurality of images of at least a portion of a surface of a filter rod, filter or filter element extending in a longitudinal direction thereof as it passes through an imaging area. A processing unit is provided for receiving image data from the image capture device and is configured to identify for each captured image a defect in the filtering material. A rolling mechanism is also provided and configured to cause the filter rod, filter or filter element to roll as it passes through the imaging area. By rolling the filter rod as it passes through the imaging area, it is possible to automatically inspect the longitudinal outer surface of each filter rod, filter or filter element.

The rolling mechanism is optionally configured to cause the filter rod, filter, or filter element to perform at least one full rotation as it passes through the imaging area such that the entire longitudinal surface of the rod, filter, or filter element can be inspected. The rolling mechanism is optionally configured to cause the filter rod, filter or filter element to roll at a substantially constant rate, wherein the image capture rate of the image capture device is synchronized with the rolling rate of the filter rod, filter or filter element to obtain an image to ensure that the capture operation is more reliable, wherein the image capture rate of the image capture device is a plurality that covers all of the perimeter of at least a portion of the longitudinally extending surface of the filter rod, filter or filter element passing through the imaging area. It is enough to capture an image of a dog. The image capture device is configured to capture six images of a filter rod, filter or filter image as it passes through the image area, each image covering about 60 ^o of circumference. This turns out to be a good compromise when considering image capture rate, imaging area and rolling rate.

A detector may be provided coupled to the transporter and configured to provide an output indicative of a distance traveled by the transporter. The processing unit may be configured to determine an image capture rate of the image capture device based on a radius or perimeter of a filter rod, filter or filter element to be evaluated and an output of the detector. In particular, the output of the detector may be a series of pulses or binary outputs, where a change in each pulse or state indicates that the transporter has traveled a fixed distance, and the image capture rate is the rate at which the transporter moves the filter rod. , may be set based on the number of pulses generated when moving a distance equal to the circumference of the filter or filter element. The image capture rate may be set based on the number of pulses or state changes that separate successive images, the number of which occurs when the transporter moves a distance equal to the circumference of the filter rod, filter or filter element. Number of pulses divided by the number of images required to image substantially the entire perimeter of at least a portion of the longitudinally extending surface of the filter rod, filter or filter element passing through the imaging area. The detector may be an encoder, in particular a rotary encoder that may be coupled to a shaft used to drive a conveyer.

Multiple filter rods, filters or filter elements optionally pass through the imaging area simultaneously to increase the throughput of the system.

The system may optionally further include a conveyer for conveying the filter rod, filter or filter element through the imaging area, the rolling mechanism being configured to cause the filter rod, filter or filter element to pass through the imaging area. and a roller unit configured to contact them when in contact with them and induce them to roll. This arrangement allows control over the rolling rate and where the rolling occurs. The conveyer optionally includes a first belt, and the roller unit optionally includes one or more second belts, the first belt being within a filter rod, filter or filter element in contact with the first and second belts. It has a different speed than the second belt to induce rolling. Using the belt in this way allows for more precise control of the rolling speed of the rod. The first belt may optionally move in the opposite direction of the second belt. The first belt may optionally move at a higher speed with the second belt.

The roller unit is optionally supported relative to the conveyor such that the one or more second belts are substantially parallel to the first belt over the imaging area. One or more second belts are separated from the first belt by a distance such that the filter rods, filters or filter elements contact both the first belt and the one or more second belts as they pass through the imaging area. This ensures rolling of the rod while avoiding excessive pressure on the rod that may cause the system to jam.

The roller unit optionally includes one or more adjusters for regulating the separation of the roller unit from the conveyer. In particular, the roller unit optionally comprises a main support used to mount the roller unit in a fixed position relative to the conveyer, the main support being between the roller unit and the conveyer as determined by the adjuster. adjustable mounting means to accommodate different separations of Allowing this adjustment mechanism allows for fine tuning of the pressure applied on the rod by the rolling unit to cause the rod to roll.

The rolling mechanism may optionally be a slope or ramp with an inclination angle that causes the filter rod, filter or filter element to roll under gravity through the imaging area. The tilt angle may be between 5° and 25°, in particular between 10° and 15°. The system may optionally further comprise a fluted wheel comprising a plurality of grooves or flutes around it, each of which engages a single filter rod, filter or filter element. ), wherein the fluted wheel is positioned between the rolling mechanism and a container holding a plurality of filter rods, filters or filter elements. This arrangement allows for a simplified inspection method requiring less power input and maintenance.

The processing unit may optionally be configured to identify defects in the filtering material by comparing images of one or more filter rods, filters or filter elements with images of one or more standard filter rods, filters or filter elements. The processing unit may optionally determine a value for the amount of visible defects in at least a portion of the longitudinal surface of the filter material and compare it to a predetermined value.

Optionally, removal means may be included to remove the filter rod, filter or filter element from the pre-selected path if it is identified as containing one or more defects. The processing unit may optionally be in communication with the removal means, wherein the processing unit and removal means are included within the imaging area when an image is captured and the image is captured and the image is determined to include one or more defects. configured to remove any filter rods, filters or filter elements that have been

According to an embodiment of the present invention, there is provided a corresponding method for evaluating the acceptability of a product filter rod, filter or filter element comprising a longitudinally extending core of filtering material as it moves along a predefined path. This way:

a) causing the filter rods, filters or filter elements to roll as they pass through the imaging area;

b) capturing a plurality of images of the longitudinally extending surfaces of the filter rod, filter or filter element as they roll through the imaging area; and

c) processing the image to identify defects in the filtering material.

Also as a computer program, when executed, controlling the image capture device to capture a plurality of images of at least a portion of a surface of a filter rod, filter or filter element extending in a longitudinal direction thereof as it passes through an imaging area, and A computer program may be provided that causes the system described herein to perform the method described herein by processing the image to identify defects in the filtering material.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the present invention will now be described with reference to the accompanying drawings:
1 is a cross-sectional view of a tobacco smoke filter element;
2 is a top-down view of a plurality of filter rods comprising filter elements along a predefined path through an imaging area;
3 is a diagram illustrating a general stage involved in the inspection of a filter rod, filter or filter element, according to an embodiment of the present invention;
4 is a schematic diagram illustrating a system for evaluating the acceptability of a product filter rod, filter or filter element, in accordance with an embodiment of the present invention;
5 is a diagram illustrating an example of how rod rolling may be induced using upper and lower conveyer belt configurations;
6 is a cross-sectional view of a tobacco smoke filter element showing the amount of arcing around a longitudinal area capturing a single image;
7 is a schematic illustration showing the movement of a rod through an image area, for subsequent image capture;
8 is a perspective view of a roller unit that may be used in an embodiment of the present invention;
9 is an illustration showing the modifications necessary to mount an existing conveyer unit in order to produce a system according to an embodiment of the present invention;
10 is a diagram illustrating a side view and a top-down view of an exemplary conveyer unit;
11 shows side, front, and perspective views of an “offline” unit for evaluating the acceptability of a product filter rod, filter or filter element, in accordance with an embodiment of the present invention; And
12 is a cross-sectional view of an alternative tobacco smoke filter element.

2 shows a top-down view of a plurality of exemplary filter rods 201 . Each rod 201 is comprised of an ingredient filter element that may be cut during the manufacturing process to produce a filter for inclusion in a cigarette. In the example of FIG. 2 , each filter rod consists of portions of an acetate tow separated by a section comprising another material, such as activated carbon 203 . A plugwrap or similar may be used to wrap the components to form a filter rod ready for subsequent processing.

As can be seen in FIG. 2 , imperfections or contamination can be seen in the fourth rod from the top of the figure. In this example, the contaminant shown is known as "carbon carry over" (CCO), in particular applicable to a dual filter configuration in which one of the filter segments is loaded into activated carbon. Loose carbon particles within a carbon segment may bury on the outer perimeter of an adjacent “white” segment during the bonding process, and these dark particles of carbon may be visible under a common wrapper used to join the segments together. CCO is one example of a type of imperfection or defect that should not be present on the filter material. Embodiments of the present invention may be adapted to inspect for a variety of other defects, such as discoloration due to tears in the wrapper or leakage of liquid that may be retained in the filter, which may be visible on the outside of the filter rod, filter article or filter element. may be A system of visual inspection of the outer surface of the combined filter may be used to monitor for such defects, or other similar defects.

3 shows a general stage involved in the inspection of a filter rod, filter or filter element, according to an embodiment of the present invention. The filter rod follows a predefined path between the input stage 301 and the output stage 304 . This may be an “in line” route that is part of the high-speed filter production process. Alternatively, as will be discussed in detail below, this may be part of a separate process using separate machinery from those used on the main production line.

The filter rods travel along a path in the direction of the arrows in FIG. 2 , generally perpendicular to their length. In stage 302 the filter rods are induced to roll as they move along a path. During rolling, the filter rod passes through a sensor area where the properties of the filter rod are measured. By rolling the rods as they pass through the sensor area, it is possible to measure the desired properties of the rods substantially all around the perimeter of the rods over at least a portion of their length. The detected properties of the rods may then be compared to predetermined properties to determine whether some of the rods passing through the sensor area contain imperfections or defects, such as contaminants or impurities.

The sensor region may be an image capture region, wherein the camera captures a plurality of images of at least a portion of each rod as it passes through the region. The image taken by the camera may be processed by a suitable processing unit to determine whether a defect exists by determining and comparing image properties. Multiple rods may be present within the image capture area at a given time, so each image may capture multiple rods. The image may be processed to determine whether any of the rods contain a defect. At least a portion of each of the multiple rods may exist within the image capture area at a given time, and thus each image may capture only a portion of each of the rods. The image may be processed to determine whether some of the rods included in the captured image contain defects. The imaging area may be limited to the portion of the rod visible in the final product, and particularly the portion adjacent to the mouth end of the cigarette, where it is most important to ensure that defects such as CCO are not present.

An optional ejection mechanism 303 provides a way to remove rods from the path that do not meet quality criteria. The emission mechanism may be controlled by the processing unit based on the analysis of the sensor information. The processing unit may transmit a signal that either retains the filter rod as it passes through the exhaust mechanism (if the rod is acceptable) or discharges the rod into the reject bin (if not). Such an ejector system may be accurate up to one rod, filter or filter element, ie it is possible to eject only the problematic rod. Alternatively, multiple rods may be emitted. Additionally, or alternatively, the processing unit may generate a visual and/or audible signal for ascertaining whether a given filter rod or set of filter rods is acceptable or not. The processing unit may also stop the production process if it determines that a certain number or proportion of filter rods, filters, or filter elements is unacceptable.

4 shows an example of one embodiment of a system or apparatus for evaluating the acceptability of a product filter rod, filter, or filter element. The system generally includes a path for the filter rods parallel to a conveyor 402 that carries the rods in the direction indicated by the arrows; an imaging area 403 covered by an image capture device in the form of a camera 404 ; a rolling mechanism in the form of a roller unit 405 and an ejection mechanism in the form of a rejector 406 which may be triggered by a triggering mechanism 407 . A processing unit 408 is provided to receive image data from the camera 404 and perform an analysis to determine the acceptability of the imaged rod. The processing unit may suitably control the emitter 406 and emit an alert using one or more output devices, such as an optional display 409 .

The filter rods are carried along the path by a conveyer 402, which may be any suitable type of conveyer for conveying the rods. Preferably the conveyor transports the rods at least partially in a direction substantially perpendicular to the linear path as shown in FIG. 2 . In particular, the conveyor 402 may include one or more moving belts on which the rods are placed. As the rods move along the conveyer, they contact the roller unit 405 which causes the rod to rotate about a longitudinal axis while traveling along a path defined by the conveyer through the imaging area.

The roller unit 405 may include one or more actuating means to induce rolling within the rod. In particular, as shown in FIG. 4 , the roller unit 405 may include one or more belts 410 moving in a direction substantially parallel or anti-parallel to the belt of the conveyor 402 . By providing the rolling unit on the existing (lower) belt on the main conveyor, an upper/lower belt configuration is formed ^{that allows the rods to rotate 360 0 full around their longitudinal axis while in the imaging area.} This allows at least a portion of the longitudinal region of each rod to be imaged over its entire perimeter to detect defects. The rolling rate is set so that the rods do not jam and there is sufficient space between the rods to reliably distinguish between the individual rods within the captured image.

5 provides an example of how the rolling of the rod may be induced when using upper and lower conveyer belt configurations. The four examples of FIG. 5 show a lower belt/transferr 502 , an upper belt/transferr 505 and an exemplary rod 501 , respectively. One of the belts (preferably the lower belt of the main conveyor) is used to convey the rod along a predetermined path, while the other belt (preferably the upper belt) is used to control the rotation of the rod. It will be appreciated that a combination of motion and/or velocity of the upper and lower belts may be used to simultaneously induce rotation within the rod for imaging purposes while simultaneously transporting the rods along a predetermined path.

In Example A, both the upper and lower belts are stopped, meaning that the rods are also stopped.

In Example B, the lower conveyer is moving in the first direction at a relatively high rate, for example, 11 to 15 meters per minute, while the upper conveyer is stationary. This configuration makes it possible to transport the rods along the path while inducing rotation, so that the roller unit 405 is designed to contact the rods as they pass under them and is replaced by a fixed contact member such as a plate that allows them to roll. Possible configurations can be envisaged. However, such a configuration may jam the rods, as the rods may not travel reliably enough in the direction of movement of the lower belt along a predetermined path.

In Example C, the lower conveyer is moving in a first direction at a relatively high rate, eg, 11 to 15 meters per minute, and the upper conveyer is moving at the same or similar rate but in the opposite direction. This configuration will cause the rods to rotate as shown, but will not translate or move the rods along a path through the imaging area.

A preferred example is that the lower conveyer is moving in the first direction at a relatively high rate, for example 11 to 15 meters per minute, and the upper conveyer is moving in the opposite direction at a relatively low rate, for example 4-5 meters per minute. It is shown in D. This configuration in which a first transporter (eg lower transporter) moves in a first direction at a first rate and a second transporter (upper transporter) moves in the opposite direction at a second rate determines the speed and guidance of transport The second rate is lower than the first rate, providing a favorable compromise between the speed of rolling applied.

Examples where the upper and lower conveyers move in the same direction but at different rates are also possible.

Referring again to FIG. 4 , the camera 404 is directed with its lens focused on the imaging area 403 , beyond which the filter rod passes along the main conveyor 402 . The imaging area may be divided into two or more sub-regions as shown in FIG. 2 . This may be achieved by using multiple cameras to select regions of the image for processing using software running on the processor. Preferably the image areas are established by setting the area for each segment of the filter (eg the white segment) that needs to be analyzed for defects using control software for use with the camera system. The camera may be any suitable high-speed camera. Digital cameras of the CCD variety are particularly suitable. One example of a suitable camera includes the Keyence(TM) CV-200M CCD with a CA-L H50 lens.

The camera is coupled in communication with a processing unit 408 , which may be suitably programmed computer-executed image processing software. Examples may include a control unit such as a model CV-5501, or CV-3001, all available from Keyence(TM). The processing unit determines from an image such as that shown in FIG. 2 a value indicative of the amount of contaminants or defects in the image (equal to the number of pixels), and compares this value with a predetermined value to determine whether the filter rods in the image are acceptable. Evaluate. In some instances, such as looking for CCO, any detectable amount of contaminant/impurity may be too high, thus causing the rod to be released.

In embodiments related to CCO defects the parameters may include the strength and/or size of the CCO defect. This may be detected by identifying an image portion or pixel that has a specific color or other property that matches that of an acceptable filter material or a color or other property that is different from it. The defect may only be of interest near the portion of the filter rod that would be proximate to the user's mouse in use if formed in a complete cigarette. In this way, the image region may be defined as one or more discrete regions, for example as shown in FIG. 2 , including the region of the rod that will be proximal to the mouth-end region.

The processing unit 408 may optionally be coupled to a display or screen 409 , which may require a TV tuner or similar device. The screen may provide information such as progress to the user if imperfections are detected. For example, a signal “NG” may be provided if it is determined that the imaged rod portion within the imaging area is unacceptable.

In order to capture and analyze the area of each rod over its entire perimeter as it passes through the imaging area, it is necessary to take multiple images while the rod is rolling. In the example of Figure 4, a linear system is used to cause the rod to move and rotate at a constant speed through the imaging area. It is possible to capture part of the rod area around the entire perimeter by taking images at regular intervals. This constant spacing should be substantially synchronized with the speed at which the rod rotates as it passes through the imaging area as closely as possible.

One image of the rod may capture approximately 60 degrees of the arc around it for a given portion of its length, generally in the longitudinal direction. This is shown in FIG. 6 , where the rod is shown as a cross-section. Therefore, at least six images of a given rod are required to ensure that the longitudinal surface of the rod has been analyzed over its entire perimeter for defects. 2 shows an exemplary imaging area 403 configured to cover a sufficient area to allow a sufficient number of images to be taken as the rod passes. Consequently, at any given time, the imaging area may include a number of rods (or a portion of the number of rods) corresponding to the number of images captured during the time required for a particular rod to pass through the imaging area. In the example of FIG. 2 , this corresponds to six rods. 7 shows the movement of the rod through the image area during the first and second images. As shown, the position of each rod has been shifted one to the left, and six images are needed for the rod to pass through the entire imaging area. In other examples, more images may be taken, and if 8 images are taken, more rods, such as 8 rods, may be present when the image is taken to ensure full coverage with a greater degree of reliability. Preferably the rolling rate of the rod is controlled to perform at least one complete rotation as the rod passes through the imaging area. Even more preferably the rod performs substantially one complete rotation. This ensures optimum process efficiency as a minimum number of images need to be taken and processed to cover the entire perimeter of the rod.

The capture rate and imaging area of the camera may be set by trial and error or by any suitable method, such that images of all segments of the outer surface of the rod as indicated in FIG. 6 are captured. For example, a test rod may be marked on its surface at suitable regularly spaced locations around its perimeter to divide the rod into a predetermined number of segments, eg, six segments as indicated in FIG. 6 . An image is then captured and it is determined whether all marked sections are captured by the resulting image. If all sections are captured then the capture rate and image area are sufficient, otherwise the capture rate and/or image area should be increased. Similarly, this testing can be used to adjust the image capture rate and image area for greater efficiency. If all segments are captured but multiple images of one or more segments are captured, this indicates that the image capture rate or image area is too large. These parameters can be appropriately reduced until each segment is captured only once.

Alternatively, the capture rate of the camera may be determined based on the rate at which the conveyer is operated and the circumference of the filter rod being inspected. Also included in the system of FIG. 4 is an encoder 413 . The encoder may be a rotary type encoder coupled to the main feeder 402 , in particular coupled to a rotating shaft used to apply thrust to the main feeder through which the filter rod moves accordingly. For example, the rotating shaft may be coupled to one of the pulleys that actuate the main conveyor. The encoder is also coupled to the processing unit 408 , in particular to an image processing unit or an image controller, for example “F210” within the processing unit. The encoder may be coupled to the image processing unit via a programmable logic circuit “PLC”. As an example, the encoder may operate at about 1000 pulses per revolution, an example of a suitable encoder is the Omron(TM) EB6B2-CWZ6C.

An encoder may be used to determine the rate of image capture required by the system. A value P _c may be determined for the number of pulses output by the encoder per unit of distance traveled by the main transporter. This can be determined by dividing the number of pulses occurring in a given time period by the distance traveled by the transporter in that time period. Dividing P _{c by the perimeter of the rod being tested gives P r} the number of pulses output by the encoder during a single rotation of the rod. Dividing this value P _r by the number N of images required to examine the entire longitudinal area of the rod gives the number of pulses output by the encoder between the images, and thus the rate of image capture required by the imaging device. . As an example, for a movement of the feeder of 120 mm, the encoder may output 560 pulses, resulting in a value _{of P c of 4.6 pulses per mm.} For a filter rod with a circumference of 16.7 mm, _{the value of P r} will be 76.8 pulses during a single rotation of the rod. For N=6, the number of pulses between images becomes 12.8, which means that one image has to be captured every 12.8 pulses to image the entire longitudinal area of the rod. The calculated capture rate may be set automatically based on a command from the processing unit, or it may be set manually. The release of the rod may require the release of multiple rods in some embodiments. When images are taken to detect impurities or defects, it may not be possible or efficient to precisely identify which rods in the image contain the defect. For example, the imaging area may cover a length corresponding to the number N of rods passing along the main conveyor. In the example of Figure 2, the imaging area covers a length corresponding to six rods (N = 6). Instead of trying to determine which rods contain the defect, it may be more straightforward to eject all rods contained within the image. In this way, the processing unit only needs to identify a defect such as a CCO in an image, and all rods in that image can be ejected. This multiple release can be achieved by waiting for a period of time to release the rods. This period of time corresponds to the amount of time required for all rods in the imaging area at the time of capturing the image containing the defect to travel to a point on the path/transferr from which they can be ejected.

4 also shows an illumination 411 used to illuminate the imaging area. Additionally, or alternatively, backlighting 412 may be provided, wherein the light source is positioned with the imaging area between the light source and the camera. Such illumination allows defects to be identified more accurately, and also allows defects to be identified through a rod wrapper (eg plug wrap).

8 shows an example of a roller unit 405 that may be used in an embodiment of the present invention. The roller unit comprises a gear motor 802 used to drive at least a first pulley or wheel 803 . Belt 804 passes over first pulley 803 and second pulley 805 causing the belt to move in a conveyor type motion. Optionally, an additional belt 807 may be provided. A third pulley 806 may be coupled to the first pulley by a shaft, a fourth pulley 808 may be coupled to a second pulley by a shaft, and the second belt 807 may be coupled to the third pulley Providing a second belt passing over 806 and fourth pulley 808 may more reliably direct and control the rolling of the contacting rod.

The roller unit can be fitted to an existing conveyer system to provide a rolling mechanism that allows the rods to roll as they pass through the imaging area. The main support 809 couples the roller unit to the conveyor belt support structure and provides means for supporting the roller unit thereon. The main support 809 may be configured such as the conveyor described in connection with FIG. 10 , using an adjustable coupling device, such as an elongated or oval hole 810 , that receives a bolt and connects to the conveyor support structure in an adjustable manner. It may be attached to the side of the main conveyor. The bolt can be tightened to lock the rolling system relative to the conveyor, eliminating any movement.

An adjustable mechanism may be provided for varying heights of the roller unit relative to the lower conveyer belt, and therefore of the upper conveyer belt. In the example of FIG. 8 , the mechanism is in the form of a plurality of separate adjusters 811 located at alternate corners of the main frame of the roller unit. The adjusters may be in the form of bolts or screws that can each be adjusted independently so that some extend under the frame of the roller unit and hold the roller unit at a certain height relative to the lower conveyer by contacting the support structure of the lower conveyer. The lower conveyer height is adjusted so that the upper conveyer 804 applies sufficient friction to cause the rod to roll while preventing the upper conveyer 804 from applying excessive pressure to the rod that could contact any passing filter rod and cause machine jamming. The adjustable coupling arrangement on the main support 809 may be configured to allow the main support to be attached to the main conveyor while accommodating different heights relative to the adjuster 811 thanks to the elongated or elongated hole 810 .

Optionally, one or more sensor supports 812 may be provided. The sensor support may be used to support the sensor to count and check its position as the rods pass through the system. Alternatively, a shift register may be used to track the rods.

9 shows the modifications necessary to mount an existing conveyer unit in order to produce a system according to an embodiment of the present invention. In addition to adding a rolling unit in the discharge system, and a suitable camera system, the speed of the conveyer unit is preferably adjusted by changing the ratio of the conveyer pulleys/gears. The conveyer unit speed is increased, for example from 11 meters per minute to 15 meters per minute, thereby preferably ensuring that the separation between successive rods is sufficient for imaging resolution and for decreasing friction between rods, and also ensures that the rods roll while ensuring that their throughput is sufficient to handle the incoming rod rate and maintain a constant production output, while allowing rolling to be achieved as discussed above.

Fig. 10 shows an example of a lower conveyer when viewed from the side (top view) and from below (bottom view). For illustrative purposes, the main support 809 of the rolling system 405 is shown in a side view. The speed of the lower conveyer can be adjusted by changing the ratio of the pulley 1002 . The filter rods are passed on the lower conveyer belt surface by a transfer drum 1003 where they are conveyed past a rolling system 405 .

11 shows an “offline” unit for evaluating the acceptability of a product filter rod, filter or filter element. The principle of operation for the unit of FIG. 11 is similar to those described above with two differences. Firstly, this unit is designed as a free-standing unit and not as part of a production line, and secondly, the rolling mechanism uses an inclined rolling lane instead of a conveyer belt configuration to induce rolling. .

The unit 1101 includes a casing 1102 having an input 1103 for receiving a plurality of rods into the unit. The input unit may be in the form of a hopper or a mini hopper. Adjacent to the hopper is a transfer device 1104 for transferring the rod from the input to the imaging area. The delivery device may, for example, be in the form of a fluted drum. A fluted drum has about itself a series of lateral flutes or grooves extending across the width of the fluted drum in the same direction as the axis around which the fluted drum rotates. The longitudinal axis of each groove is therefore oriented to be the same as the longitudinal axis of the longitudinally extending filter rod. Each groove is sized such that it accepts product filter rods from the hopper and holds them (eg, by suction) as the fluted drum rotates to transport the rods for subsequent processing. The fluted drum (and hopper) therefore provides a leading flow of product filter rods, wherein each rod in the flow is oriented with the ends of the rods facing substantially perpendicular to the direction of travel.

After exiting the fluted drum, the filter rod is passed onto a rolling lane 1105 . A rolling lane is preferably an inclined path through the imaging area to a receptacle 1106, such as a tray, through which the rod may roll. The rolling lane may have a substantially planar rolling surface. The rolling lanes are preferably inclined between 5 and 25 degrees from horizontal, and in particular may be comprised between about 10 and 15 degrees from horizontal.

A camera 1107 is provided in a manner similar to the previous embodiment, with the camera focused on the imaging area on the rolling lane 1105 . The camera captures multiple images of the rods as they roll through the imaging area to cover the entire longitudinal surface of each rod. A methodology similar to that described with respect to FIG. 4 may be employed to determine optimal parameters for camera capture rate and imaging area size. The imaging area, where the test rods are imaged on every segment as shown in FIG. 6 , has an additional margin for potential error covered by increasing that area by a predetermined error margin, such as 10%, along the direction of movement of the rod. It may be set to While multiple rods may be imaged at any one time, preferably only one single rod may be in its imaging area, or on a rolling lane, at any one time.

It will be appreciated that the various embodiments described above include different alternative features that may be used in combination with any other alternative features as suitable. While other embodiments are described, such as using two or more conveyer belts, for example, the embodiment shown in FIG. 11 uses an inclined ramp to induce rolling in the filter rod. A ramp may be used in embodiments using a conveyer belt arrangement (as shown in FIG. 4 ) instead of the rolling mechanism shown. Alternatively, an inclined conveyer belt may be used, whereby the rolling is induced according to the angle of the conveyer belt, the speed and direction of the conveyer belt being adjusted to obtain optimum rolling of the filter rod, thereby imaging Allows the device to image around the entire perimeter of the rod. Additionally, the embodiment of FIG. 11 may equally incorporate the type of conveyor/roller mechanism shown in FIG. 4 or described above.

It will be appreciated that embodiments of the present invention may be used with any suitable filter or filter article. Different sized filter rods may be used with any of the embodiments of the invention described herein. The system described herein may be adapted to inspect filter rods/elements of any suitable size, for example embodiments may be configured to operate with conventional filter rods/elements having a perimeter of 14 to 28 mm. have. Filter rods of different shapes or structures may also be used with embodiments of the present invention. 12 shows one stage (downstream or mouth end) of a further example of a filter element for the filter shown in FIG. 1 ; The filter element comprises a thermoformed longitudinally extending core 1 of filtering material of substantially annular cross-section. The longitudinally extending core 1 is again produced by thermoforming a calcined cellulose acetate fibrous tow, but also with longitudinal channels or bores 2 of circular cross-section extending from one end of the core to the other. ) is defined. The filter element thermoforms a stream running the length of the calcined tow of cellulose acetate to form a tube or cylinder running in continuous length by methods well known in the art, such as in GB 2091078 and references herein. can also be formed. The continuously running thermoformed tube is then cut into a finite length product rod comprising two or more filter elements joined together at the ends. The dual product rod is further processed by methods well known in the art to become a dual filter (eg using a filter maker) and filter cigarette. Other filter elements that may be used may have different channel cross-sections or may have no channels at all.

Claims (1)

A device as described in the detailed description or as shown in the drawings.

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