KR102568342B1 - Detection system - Google Patents

Abstract

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 404 configured to capture a plurality of images of at least a portion of a longitudinally extending surface of a filter rod, filter or filter element as it 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 defects in the filtering material for each captured image. A rolling mechanism 405 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.

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, for example as part of a filter manufacturing process.

Conventional filtering materials used in cigarette filters are formed as a continuous tow of filamentary cellulose acetate, which is gathered together in a rod to form a filter, or filter element, having a generally cylindrical structure.

The manufacture of cigarette filters, or related products, having a cylindrical structure is well known in the art. Such filters typically include a generally cylindrical core extending longitudinally 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 in the range of eg 14 to 28 mm. The longitudinally extending core 1 is produced by thermoforming plasticised cellulose acetate fibrous tow. Filters composed of different materials such as paper may also be used. The filtering material may be composed of one or more different segments. For example, a filter element may be coupled or adjacent to another filter element (not shown in FIG. 1) and an adjacent filter element wrapped with a plugwrap at its upstream end to form a dual filter as is well known in the art. there is. A dual filter comprising a filter element is joined to 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 adjacent end of the wrapped tobacco rod. to form a filter cigarette.

It is possible for imperfections or imperfections to be incorporated into 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 customers, and also that any errors in production that cause imperfections may be quickly rectified by stopping production.

To date, there is no simple automated technique available for monitoring visual properties across the outer surface of a filter. Instead, visual quality checks will be performed in a set sequence by skilled personnel after filter production. Clearly, this is time consuming, expensive and subject to judgment depending on the operators involved. Furthermore, if the error is common to a large number of product filters, it may be due to problems in the manufacturing process; Monitoring product quality after production does not allow for stopping production if there is a problem with the process. Accordingly, there is a need for a visual inspection system that is fast, accurate, reliable, and easily integrated "in the production line" as part of a 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, a system for evaluating 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 is provided. The system includes an image capture device configured to capture a plurality of images of at least a portion of a longitudinally extending surface of a filter rod, filter or filter element as it passes through an imaging area. A processing unit is provided to receive image data from the image capture device and is configured to identify defects in the filtering material for each captured image. 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 so 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 produce an image To ensure that the capture operation is more reliable, the image capture rate of the image capture device is plural, covering the entire circumference of at least a portion of the longitudinally extending surface of the filter rod, filter or filter element passing through the imaging area. 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 ^degrees of circumference. This turns out to be a good compromise when considering image capture rate, imaging area and rolling rate.

A detector coupled to the conveyor and configured to provide an output indicative of the distance traveled by the conveyor may be provided. The processing unit may be configured to determine an image capture rate of the image capture device based on a radius or circumference 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, each pulse or change in state indicating that the conveyor has moved a fixed distance, and the image capture rate is such that the conveyor 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, which number occurs when the conveyor moves a distance equal to the circumference of the filter rod, filter or filter element. The number of pulses divided by the number of images required to image substantially the entire circumference 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 conveyor.

Multiple filter rods, filters or filter elements are selectively passed simultaneously through the imaging area to increase the throughput of the system.

Optionally, the system may further comprise a conveyor for conveying the filter rods, filters or filter elements through the imaging area, the rolling mechanism to cause the filter rods, filters or filter elements to pass through the imaging area. and a roller unit configured to contact them and induce them to roll when they are in contact with them. This arrangement allows control over the rate of rolling and where the rolling occurs. The conveyor optionally comprises a first belt and the roller unit optionally comprises one or more second belts, the first belt being in a filter rod, filter or filter element contacting the first and second belts. It has a different speed than the second belt to induce rolling. Using the belt in this way allows more precise control of the rolling speed of the bar. 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.

Optionally, the roller unit is 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 belts 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 which may cause the system to jam.

The roller unit optionally includes one or more regulators that regulate the separation of the roller unit from the conveyor. In particular, the roller unit optionally includes a main support used to mount the roller unit in a fixed position relative to the conveyor, the main support being between the roller unit and the conveyor as determined by the adjuster. and adjustable mounting means for accommodating different separations of This adjustment mechanism allows 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 having an inclination angle that allows 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 its circumference, 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 that requires less power input and maintenance.

Optionally, the processing unit may be configured to identify defects in the filtering material by comparing an image of one or more filter rods, filters or filter elements with images of one or more standard filter rods, filters or filter elements. Optionally, the processing unit may 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 predefined 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 capture an image and if the image is captured and it is determined that the image comprises one or more defects, the processing unit and the removal means include within the imaging area. and to remove any filter rods, filters or filter elements that have been removed.

According to one embodiment of the present invention, a corresponding method is provided for assessing acceptability when a product filter rod, filter or filter element comprising a longitudinally extending core of filtering material 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 a longitudinally extending surface of the filter rod, filter or filter element as it rolls through the imaging area; and

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

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

Embodiments 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 containing filter elements following a predefined path through an imaging area;
3 is a diagram illustrating the general stages involved in inspecting a filter rod, filter or filter element, in accordance with 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, according to one embodiment of the present invention;
5 is a diagram showing an example of how rolling of a rod may be induced using an upper and lower conveyor belt arrangement;
6 is a cross-sectional view of a cigarette smoke filter element showing the amount of arc around a longitudinal area capturing a single image;
7 is a diagrammatic 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;
Figure 9 is an illustration showing the modifications that may need to be made to an existing conveyor unit to produce a system according to an embodiment of the present invention;
10 is a diagram illustrating side and top-down views of an exemplary conveyor 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, according to one 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 number of exemplary filter rods 201 . Each rod 201 is composed of component filter elements that may be cut during the manufacturing process to produce the filter to be incorporated into a cigarette. In the example of FIG. 2 , each filter rod is composed of portions of acetate tow separated by sections containing another material, such as activated carbon 203 . Flowwrap or the like may be used to wrap the components to form a filter rod ready for further processing.

As can be seen in FIG. 2, an imperfection or contamination can be seen on the fourth bar from the top of the drawing. In this example, the contaminant shown is known as “carbon carry over” (CCO), and applies specifically to dual filter configurations in which one of the filter segments is loaded into activated carbon. Loose carbon particles within the carbon segments may bury themselves on the outer periphery of adjacent "white" segments during the bonding process, and these dark particles of carbon may be visible under the common wrapper used to bond the segments. A CCO is one example of a type of imperfection or defect that should not be present on a filter material. Embodiments of the present invention may be adapted to inspect filter rods, filter articles or filter elements for a variety of other defects, such as discoloration due to tears in the wrapper or leakage of liquid that may be retained within the filter, which may be visible from the outside. may be A visual inspection system of the outer surface of the bonded filter can be used to monitor for these or other similar defects.

Figure 3 shows the general stages 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 from the input stage 301 to 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 machinery separate from those used on the main production line.

The filter rods move along the path in the direction of the arrow in Figure 2, generally perpendicular to their length. At stage 302 the filter rods are induced to roll as they travel along the 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 region, it is possible to measure a desired property of the rods substantially all around the circumference of the rods over at least a portion of their length. The detected properties of the rods may then be compared to a pre-determined property to determine if some of the rods passing through the sensor area contain imperfections or defects, such as contaminants or impurities.

The sensor area may be an image capture area, where the camera captures multiple images of at least a portion of each wand as it passes through the area. Images captured by the camera may be processed by suitable processing units to determine and compare image properties to determine if a defect exists. Multiple peaks may exist 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 defects. At least a portion of each of the multiple rods may be present 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 if some of the rods included in the captured image contain defects. The imaging area may be limited to the portion of the wand visible in the final product, and in particular the portion adjacent to the mouth end of the cigarette, which is the most important area to ensure that defects such as CCO do not exist.

An optional ejection mechanism 303 provides a way to remove rods from the path that do not meet quality criteria. The ejection mechanism may be controlled by the processing unit based on analysis of the sensor information. The processing unit may send a signal to retain the filter rod as it passes through the ejection mechanism (if the rod is acceptable) or to release the rod into a reject bin (if not acceptable). Such an ejector system may be accurate to one rod, filter or filter element, ie it is possible to eject only the rod in question. Alternatively, multiple rods may be emitted. Additionally or alternatively, the processing unit may generate a visual and/or audible signal to ascertain 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 percentage of filter rods, filters or filter elements are not acceptable.

4 illustrates an example of one embodiment of a system or apparatus for evaluating the acceptability of a product filter rod, filter or filter element. This system generally routes the filter rods parallel to the conveyor 402 which conveys 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; It includes 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 camera 404 and perform analysis to determine the acceptability of an imaged rod. The processing unit may suitably control emitter 406 and emit an alert using one or more output devices, such as optional display 409 .

The filter rods are conveyed along the path by conveyor 402, which may be any suitable type of conveyor for transporting 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, conveyor 402 may include one or more moving belts on which rods are placed. As the rods move along the conveyor, they contact roller units 405 which cause the rods to rotate around a longitudinal axis while moving along a path defined by the conveyor through the imaging area.

The roller unit 405 may include one or more actuating means for inducing rolling within the rod. In particular, as shown in FIG. 4 , roller unit 405 may include one or more belts 410 that move in a direction substantially parallel, or anti-parallel, to the belts of 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 be rotated a full 360 ^° around their longitudinal axis while in the imaging area. This allows at least a portion of the longitudinal area of each rod to be imaged over its entire circumference to detect defects. The rolling rate is set such that there is sufficient space between the rods so that the rods do not jam and to reliably distinguish between the individual rods in the captured image.

5 provides an example of how rolling of a rod may be induced when using an upper and lower conveyor belt configuration. The four examples of FIG. 5 show lower belt/conveyor 502 , upper belt/conveyor 505 and 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 speed of the upper and lower belts may be used to transport the rods along a predetermined path while simultaneously inducing rotation within the rods for imaging purposes.

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

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

In Example C, the lower conveyor is moving in the first direction at a relatively high rate, for example 11 to 15 meters per minute, and the upper conveyor 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 where the lower conveyor is moving in the first direction at a relatively high rate, eg 11 to 15 meters per minute, and the upper conveyor is moving in the opposite direction at a relatively low rate, eg 4-5 meters per minute. is shown in D. This configuration, in which the first conveyor (eg the lower conveyor) moves in a first direction at a first rate and the second conveyor (the upper conveyor) moves in the opposite direction at a second rate, determines the speed and direction of transport. It provides an advantageous compromise between the speed of rolling, the second rate being lower than the first rate.

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

Referring again to FIG. 4 , the camera 404 is directed with its lens focused on the imaging area 403 , past which the filter rod passes along the main feeder 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 areas of the image for processing using software running on the processor. Preferably, the image areas are established by using control software for use with the camera system to set the area for each segment of the filter (e.g. white segment) that needs to be analyzed for defects. 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 a Keyence(TM) CV-200M CCD with a CA-L H50 lens.

The camera is communicatively coupled to a processing unit 408, which may be appropriately programmed computer implemented image processing software. Examples may include a control unit such as the model CV-5501, or CV-3001, both available from Keyence(TM). The processing unit determines from an image such as that shown in FIG. 2 a value indicative of the amount (equal to the number of pixels) of contaminants or defects in the image, and compares this value to 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 emission of rods.

In embodiments involving CCO defects, the parameters may include the intensity and/or size of the CCO defect. This may be detected by identifying image portions or pixels that have a particular color or other property that matches or differs from that of an acceptable filter material. The defect may be of interest only near the portion of the filter wand that, if formed into a complete cigarette, would be close to the user's mouse in use. In this way, the image area may be defined by one or more discrete areas, for example as shown in FIG. 2, including the area of the rod that will approximate the area of the mouth end.

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 the user with information such as progress if an imperfection is detected. For example, a signal "NG" may be provided if it is determined that the portion of the rod imaged within the imaging area is unacceptable.

To capture and analyze the area of each rod over its entire circumference 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 a portion of the rod area around the entire circumference 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 a rod may capture about 60 degrees of arc around it for a given portion of its generally longitudinal length. This is shown in Figure 6, where the rod is shown in cross section. Therefore, at least 6 images of a given rod are required to ensure that the longitudinal surface of the rod has been analyzed for defects over its entire circumference. 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 wand passes. Consequently, at any given time, an imaging area may contain a number of rods (or portions of that 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 figure 2, this corresponds to 6 rods. Figure 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 shifted to the left one by one, and six images are required for the rod to pass through the entire imaging area. In other examples, more images may be taken, and if 8 images are taken, there may be more bars, such as 8 bars, when an image is taken to ensure full coverage with a greater degree of reliability. Preferably the rolling rate of the wand is controlled to perform at least one full rotation of the wand as it passes through the imaging area. Even more preferably the rod performs substantially one complete revolution. This ensures optimal process efficiency since a minimum number of images need to be taken and processed to cover the entire circumference 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, the test rod may be marked on its surface at suitable regularly spaced locations around the circumference to divide the rod into a predetermined number of segments, for example six as indicated in FIG. 6 . The 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 must be increased. Similarly, such testing can be used to adjust 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 conveyor is operated and the circumference of the filter rod being inspected. An encoder 413 is also included in the system of FIG. 4 . The encoder may be a rotary type encoder coupled to the main conveyor 402 and, in particular, to a rotating shaft used to apply thrust to the main conveyor along which the filter rods move. For example, the rotational shaft may be coupled to one of the pulleys that actuate the main conveyor. The encoder is also coupled to the processing unit 408 and, in particular within the processing unit, may be coupled to an image processing unit or an image controller, for example “F210”. An encoder may be coupled to the image processing unit through a programmable logic circuit “PLC”. As an example, an 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 moved by the main conveyor. 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 circumference of the bar being tested gives the number of pulses P _r output by the encoder during a single rotation of the bar. Dividing this value P _r by the number N of images required to scan the entire lengthwise area of the rod gives the number of pulses output by the encoder between images, and thus the rate of image capture required by the imaging device. . As an example, for a travel of the conveyor 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 would be 76.8 pulses during a single revolution of the rod. For N=6, the number of pulses between images is 12.8, which means that one image must be captured for every 12.8 pulses to image the entire lengthwise 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 a 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 defects. 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 6 rods (N = 6). Instead of trying to determine which rods contain defects, it may be more direct to eject all rods contained within the image. In this way, the processing unit only needs to identify defects such as CCOs in an image, and all rods in that image can be emitted. Such multiple ejection can be obtained by waiting for a period of time to eject the rods. This time period corresponds to the amount of time required for all rods in the imaging area at the time of capturing an image containing defects to travel to a point on the path/transporter from which they can be ejected.

Figure 4 also shows lights 411 used to illuminate the imaging area. Additionally, or alternatively, backlighting 412 may be provided and the light source positioned with the imaging area between the light source and the camera. Such illumination allows defects to be more accurately identified and also allows defects to be identified through the 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 includes 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 to allow the belt to move in a conveyor type motion. Optionally, an additional belt 807 may be provided. The third pulley 806 may be coupled to the first pulley by a shaft, the fourth pulley 808 may be coupled to the second pulley by a shaft, and the second belt 807 may be coupled to the third pulley Providing a second belt to pass over 806 and fourth pulley 808 may more reliably direct and control the rolling of the contacting rods.

The roller unit can be fitted into an existing conveyor 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 a means for supporting the roller unit thereon. The main support 809, such as the conveyor described in connection with FIG. It can also be attached to the side of the main conveyor. The bolts can be tightened to lock the rolling system relative to the conveyor, eliminating any movement.

An adjustable mechanism may be provided for the fluctuating height of the roller unit relative to the lower conveyor belt, and therefore of the upper conveyor 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 also be in the form of bolts or screws, each independently adjustable, some of which extend below the frame of the roller unit and are capable of holding the roller unit at a certain height relative to the lower conveyor by contacting the support structure of the lower conveyor. The lower conveyor height is adjusted so that the upper conveyor 804 applies sufficient friction to cause the rods to roll while preventing the upper conveyor 804 from contacting any passing filter rods and applying excessive pressure to the rods that could cause the machine to jam. The adjustable coupling device on the main support 809 may be configured to allow the main support to be attached to the main conveyor while accommodating different heights for the adjuster 811 thanks to the elongated or elongated hole 810 .

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

Figure 9 illustrates the modifications that may need to be made to an existing conveyor unit to produce a system according to an embodiment of the present invention. In addition to adding a rolling unit in the ejection system and a suitable camera system, the speed of the conveyor unit is preferably adjusted by changing the conveyor pulley/gear ratio. The conveyor unit speed is increased, for example, from 11 meters per minute to 15 meters per minute, preferably ensuring that the separation between successive rods is sufficient for imaging resolution and for reducing friction between the rods, and also for the rods to roll. Allows rolling to be obtained as discussed above, while ensuring that their throughput is sufficient to handle the incoming bar rate and maintain a constant production output.

10 shows an example of the lower conveyor as viewed from the side (upper view) and from below (lower view). For illustrative purposes, the main support 809 of the rolling system 405 is shown in side view. The speed of the lower conveyor can be adjusted by changing the ratio of the pulleys 1002. The filter rods are passed over the lower conveyor belt surface by transfer drums 1003 as they are conveyed past a rolling system 405.

Figure 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 figure 11 is similar to that described above with two differences. Firstly, this unit is designed as a free-standing unit and not designed as part of a production line, and secondly, the rolling mechanism uses an inclined rolling lane instead of a conveyor belt configuration to guide the rolling. .

The unit 1101 includes a casing 1102 having an input unit 1103 for receiving a plurality of rods into the unit. The input unit may be in the form of a hopper or mini hopper. Adjacent to the hopper is a delivery device 1104 for conveying the wand from the input to the imaging area. The delivery device may be in the form of a fluted drum, for example. A fluted drum has around it 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 the same as the longitudinal axis of the longitudinally extending filter rod. Each groove is dimensioned so 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 an advanced flow of product filter rods, wherein each rod within the flow is oriented with the ends of the rods substantially perpendicular to the direction of travel.

After exiting the fluted drum, the filter rods pass onto a rolling lane 1105. The rolling lane is preferably an inclined path along which the rod may roll as it passes through the imaging area and into the tray-like receptacle 1106 . The rolling lane may have a substantially planar rolling surface. The rolling lane preferably slopes between 5 degrees and 25 degrees from horizontal, but may include between about 10 and 15 degrees from horizontal.

A camera 1107 is provided in a similar manner to the previous embodiment, the camera being focused on an 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 lengthwise surface of each rod. A methodology similar to that described with respect to FIG. 4 can be employed to determine optimal parameters for camera capture rate and imaging area size. The imaging area is such that the test rods are imaged on every segment, as shown in FIG. 6, with an additional margin for potential error included by increasing the area by a predetermined margin of error, such as 10%, along the direction of rod travel. may be set to. While multiple rods may be imaged at any one time, preferably only one single rod may be in the image 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 are suitable. For example, the embodiment shown in FIG. 11 uses an inclined ramp to induce rolling on the filter rods, while other embodiments are described, such as using two or more conveyor belts. A ramp may also be used in embodiments using a conveyor belt device (as shown in FIG. 4) instead of the rolling mechanism shown. Alternatively, an inclined conveyor belt may be used, whereby rolling is induced according to the angle of the conveyor belt, and the speed and direction of the conveyor belt are adjusted appropriately to obtain optimal rolling of the filter rods so that the imaging It allows the device to image around the entire circumference of the rod. Additionally, the embodiment of FIG. 11 may incorporate the same 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. Filter rods of different sizes may be used with any of the embodiments of the invention described herein. The system described herein can be adapted to inspect filter rods/elements of any suitable size, for example embodiments may be adapted to work with conventional filter rods/elements having a circumference of 14 to 28 mm. there is. Filter rods of different shapes or configurations may also be used with embodiments of the present invention. FIG. 12 shows one end (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 has longitudinal channels or bores of circular cross-section extending from one end of the core to the other (2). ) is defined. The filter element is formed by thermoforming the flow running a length of calcined tow of cellulose acetate to form a continuous length running tube or cylinder 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 finite length product rods containing two or more filter elements joined end to end. The dual product rod can be further processed into a dual filter (eg using a filter maker) and filter cigarettes by methods well known in the art. Other filter elements that may be used may have different channel cross-sections or no channels at all.

Claims (23)

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 moves along a predefined path, comprising:
a) an image capture device configured to capture a plurality of images of at least a portion of a longitudinally extending surface of the filter rod, filter or filter element as it passes through the imaging area;
b) a processing unit configured to receive image data from the image capture device and identify defects in the filtering material for each captured image; and
c) a rolling mechanism configured to cause the filter rod, filter or filter element to roll as it passes through the imaging area;
the rolling mechanism is configured to cause the filter rod, filter or filter element to perform substantially one complete rotation as it passes through the imaging area;
the rolling mechanism is configured to cause the filter rod, filter or filter element to roll at a substantially constant rate, and the image capture rate of the image capture device is synchronized with the rolling rate of the filter rod, filter or filter element;
the image capture rate of the image capture device is sufficient to capture 6 images of the filter rod, filter or filter image as it passes through the imaging area, each image covering 60 ^° of circumference;
The system further includes a conveyor for conveying the filter rod, filter or filter element through the imaging area, the rolling mechanism contacting the filter rod, filter or filter element as it passes through the imaging area, and a roller unit configured to induce them to roll;
The system further includes a detector coupled to the conveyor and configured to provide an output indicative of a distance traveled by the conveyor, wherein the processing unit determines a radius or perimeter of a filter rod, filter or filter element to be evaluated and the and determine an image capture rate of the image capture device based on an output of the detector. According to claim 1,
wherein multiple filter rods, filters or filter elements pass through the imaging area simultaneously. delete According to claim 1 or 2,
The conveyor includes a first belt, the roller unit includes one or more second belts, and the first belt is configured to induce rolling in a filter rod, filter or filter element contacting the first and second belts. system having a different speed than the second belt. delete delete delete delete According to claim 4,
The system of claim 1 , wherein the roller unit includes one or more adjusters for regulating separation of the roller unit from the conveyor. According to claim 9,
The roller unit includes a main support used to mount the roller unit in a fixed position relative to the conveyor, the main support providing differential separation between the roller unit and the conveyor as determined by the adjuster. A system comprising adjustable mounting means for accommodating. delete According to claim 1 or 2,
The output of the detector is a series of pulses, each pulse indicating that the conveyor has moved a fixed distance, and the image capture rate is such that the conveyor travels a distance equal to the circumference of the filter rod, filter or filter element. A system that is set based on the number of pulses that occur when moving. According to claim 12,
The image capture rate is set based on the number of pulses separating successive images, and the number of pulses generated when the conveyor moves a distance equal to the circumference of the filter rod, filter or filter element passes through the imaging area. is the number of images required to image substantially the entire circumference of at least a portion of a longitudinally extending surface of a filter rod, filter or filter element. According to claim 1 or 2,
wherein the detector is an encoder. According to claim 14,
Wherein the encoder is a rotary encoder coupled to a shaft used to drive the conveyor. delete delete delete delete delete delete delete delete