Abstract:
The invention relates to a sensor device ( 30; 30   a   ; 30   b   ; 30   c ) for a packaging machine ( 100 ) designed as a capsule filling and sealing machine or for a capsule control device ( 100   a ), said device having a positioning element ( 35; 35   a ) for positioning a container (c) having a longitudinal axis ( 15 ) and filled with a filling material in the region of the sensor device ( 30; 30   a   ; 30   b   ; 30   c ) and at least one radiation source ( 31; 31   a;    3   b ) and at least one detector ( 40; 40   a   ; 40   b ) for detecting the radiation after said radiation radiates through the container (c). According to the invention, the at least one radiation source ( 31; 31   a   ; 31   b ) radiates through the container (c) perpendicular to the longitudinal axis ( 15 ) thereof and the positioning element is designed as a tubular or shaft-shaped conveying element ( 35; 35   a ) which can be penetrated by the radiation in a radiation cone ( 38 ) of the radiation source ( 31; 31   a   ; 31   b ).

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a sensor apparatus for a packaging machine, which is in the form of a capsule filling and closing machine, or for a capsule monitoring apparatus. 
     A sensor apparatus such as this is known from DE 10 2005 016 124 A1. The known sensor apparatus is arranged in the area of a capsule filling and closing device and has an X-ray radiation source which passes radiation through containers in the longitudinal direction, which containers are filled with a filling material, for example a pharmaceutical product in the form of powder. A detector is arranged on the side of the container opposite the X-ray radiation source, measures the X-ray radiation after it passes through the container, and supplies this in analog form to an evaluation device. In particular, the weight of the filling material in the containers is determined by means of the sensor apparatus that is so far known. 
     This has the disadvantage that, because the containers are arranged in step-like holding holes in holding segments, when the radiation is passed through the containers, their entire cross section is not detected, with a portion of the cross section instead being covered by the holding hole. The result is therefore dependent on the geometry of the holding hole, and the measurement result may be corrupted. Additional statements can be made only with difficulty, if at all, because radiation is passed through the containers in the direction of the longitudinal axis of the containers, since the radiation passes through only a relatively limited area of the container. 
     DE 198 19 395° C.1, from the same applicant, discloses a weighing device for weighing hard-gelatin capsules, which has a feed element in the form of a flywheel which in each case moves a capsule into the area of a weighing goods holder, which is arranged in a suspended manner, and feeds the capsule on further therefrom. 
     U.S. Pat. No. 5,864,600 discloses an image-processing monitoring device, in which the filling level in containers is checked by means of a beam source, with the beam passing through the containers at right angles to their container longitudinal axis. The containers are in this case arranged at a distance from one another on a horizontally arranged feed device. 
     SUMMARY OF THE INVENTION 
     In the light of the described prior art, the invention is based on the object of developing a sensor apparatus for a packaging machine, which is in particular in the form of a monitoring device or a capsule filling and closing device, such that its measurement accuracy is improved, and further conclusions relating to the container and its filling material are made possible in a simple manner. The sensor device is intended to have a high performance and to be to feed and to position the capsules easily in the area of the sensor device. In this case, the invention is based on the idea that, by passing radiation through the container at right angles to its longitudinal axis, this allows radiation to be passed through a greater area of the container, and allows a greater area of the container to be detected, thus allowing a quantitatively and quantitatively better statement to be made about said characteristics. Furthermore, the positioning element, which is tubular or in the form of a shaft and through which the radiation lobe from the beam source can pass makes it possible to position the capsules very easily and at the same time precisely in the area of the sensor device. 
     In one preferred embodiment of the invention, an X-ray radiation source is provided as the radiation source. An X-ray radiation source not only makes it possible to detect the filling weight of the container in a simple manner, but also, for example, makes it possible to detect the filling height in the container and damage to the container, or the like. 
     Furthermore, in order to improve the performance of the apparatus and to reduce the hardware complexity, the invention particularly preferably provides for a plurality of feed elements to be arranged parallel to one another, and for a plurality of feed elements to be arranged such that they are operatively connected to a common radiation source and to a common detector. A plurality of containers can thus each be checked in one step at the same time, by means of a single radiation source and by means of a single detector. 
     One feed option for the containers whose design is simple, in the area of the radiation source, and which at the same time prevents corruption of the measurement results by parts of the apparatus, is achieved in that the containers are arranged stowed in a row in the feed element, and are fed by mutual touching contact of the containers at least in the area of the sensor apparatus. 
     It is particularly preferable if the detector is in the form of an image-evaluating detector and interacts with an evaluation device which allows digital data evaluation. This makes it possible to produce various parameters and measurement results from the signals and recordings obtained, in a simple manner. 
     In order to achieve accurate measurement, particularly of the weight of a capsule, the invention preferably provides that the at least one radiation source is additionally arranged such that it is operatively connected to a reference object, and that the detector at the same time additionally detects the image of the reference object, in addition to the image of the container, and supplies this to the evaluation device. The image of the container and/or of the capsule is therefore always related to the reference object, thus precluding absolute fluctuations between two successive images, which would lead to corruption of the measurement result. 
     In this case, in order to improve the measurement accuracy and to simplify the evaluation, it is particularly advantageous and necessary that the reference object is composed of a material which at least approximately has the same absorption characteristics for the radiation, in particular for the X-ray radiation, as the container. 
     In order to ensure that accurate and correct measurement results are achieved over the entire tolerance range of the characteristic to be measured, it is furthermore essential that the reference object has areas of different absorptions for the radiation, with at least one area being provided whose absorption, within the tolerances of the characteristic of the container to be measured, is less than the minimum absorption of the container, and an area whose absorption, within the tolerances of the characteristic of the container (c) to be measured, is greater than the maximum absorption of the container. 
     One advantageous refinement, which can be manufactured easily, of the reference object, in which the information relating to the reference object can be processed easily by means of the evaluation device, is made possible if the reference object is in the form of a wedge or step, and if the reference object is arranged such that the thickness of the reference object varies in the radiation direction of the radiation source. 
     In a further design refinement of the invention, the sensor device is followed by a weighing device which has at least one weighing cell for weighing the container. A refinement such as this provides a second monitoring option for the containers, as a result of which not only is the X-ray image used for evaluation and/or qualitative or quantitative detection of the container, but also the weighing device. In addition, this allows duplicated monitoring of the filling weight, as a result of which the two measurement results can be compared with one another, and a faulty test device can be deduced if they do not match. The claimed sensor apparatus for a packaging machine therefore operates particularly safely and reliably. 
    
    
     
       BACKGROUND OF THE INVENTION 
       Further advantages will become evident from the following description of preferred exemplary embodiments and from the drawings, in which: 
         FIG. 1  shows a simplified plan view of a capsule filling and closing machine, 
         FIG. 2  shows a sensor apparatus according to the invention, as used for a packaging machine as shown in  FIG. 1 , in the form of a schematic side view and partially sectioned, 
         FIG. 3  shows a modified sensor apparatus using holding sections, in which two rows of capsules are in each case fed, 
         FIG. 4  shows a simplified front view of the sensor apparatus as shown in  FIG. 3 , 
         FIG. 5  shows examples of images recorded by means of an apparatus according to the invention and which are supplied to a digital evaluation device for evaluation, 
         FIG. 6  shows a simplified longitudinal section through a monitoring device for capsules, 
         FIG. 7  shows a simplified side view of a capsule filling and closing machine which has been modified in comparison to  FIGS. 3 and 4 , and 
         FIG. 8  shows examples of images which have been recorded by means of the capsule filling and closing machine as shown in  FIG. 7 , which images supplied to a digital evaluation device for evaluation. 
     
    
    
     The same components are provided with the same reference number in the figures. 
     DETAILED DESCRIPTION 
       FIG. 1  shows a packaging machine in the form of a capsule filling and closing machine  100 . The capsule filling and closing machine  100  has a feed wheel  21  which is rotated in steps on a vertical axis  20 . The capsule filling and closing machine  100  is used for filling and closing capsules c, which consist of a capsule lower part a and a plugged-on cap b. In this case, the capsule c forms a container, which is elongated overall, with a longitudinal axis  15  for a filling material, which in particular is a pharmaceutical product or the like in the form of pieces or powder. 
     The feed wheel  21  has stations  1  to  12  which are arranged on the circumferential path of the feed wheel  21  and at which handling devices are arranged. The capsule filling and closing machine  100  which has been described so far is in the form of a standardized packaging machine, as a result of which there is no need to arrange handling devices at all of the stations  1  to  12 , depending on the application. Furthermore, twelve holding segments  22 , which consist of an upper part  27  and a lower part  28  (see station  12 ) are arranged at uniform angular intervals on the external circumference of the feed wheel  21 , for in each case five capsules c, which are arranged in a row. The holding segments  22  are format parts, which can be replaced on the feed wheel  21 , depending on the desired application and depending on the format of the capsules c being processed. 
     In order to hold the capsules c, each holding segment  22  in the exemplary embodiment has five holding holes  23  in the upper part  27  and in the lower part  28 . However, holding segments  22  with more than five holding holes  23  arranged in a row, and with more than one row of holding holes  23 , are also possible. The empty capsules c to be filled up are passed in an unorganized form to the station  1 , are aligned, and are supplied in an organized form to the feed wheel  21 . The caps b are then separated from the capsule lower parts a in the area of the station  3  and both are weighed, if required in advance on a sample basis, by a weighing device  25  in order to determine their net weight. In the station  4 , the caps b except for the cover are then fitted to the capsule lower parts a (not illustrated) thus allowing the capsule lower parts a to be filled with filling material in the station  5 . In the area of the station  7 , the caps b are once again moved to cover the capsule lower parts a and, in the station  8 , individual capsules c are weighed on a sample basis on a further weighing device  26  process which is gross weighing. In the area of the station  9 , the capsules c are checked for the presence of their caps b, with capsules c and individual capsule lower parts a and caps b being ejected in the area of the station  10 . A sensor apparatus  30  according to the invention is arranged in the area of the station  11 . Finally, the holding segments  22 , which have in the meantime been emptied, are cleaned, in particular by means of airblast, in the area of the station  12 . 
     By way of example, reference is furthermore made with respect to the precise operation of a capsule filling and closing machine such as this to DE 10 2005 016 124 A1, from the same applicant, which describes further details relating to the fundamental operation and method of operation thereof. 
     As can be seen in particular in  FIG. 2 , the sensor apparatus  30  is arranged above the lower parts  28  of the holding segments  22 . The sensor apparatus  30  operates by means of a radiation source, which is in the form of an X-ray radiation source  31 . 
     In addition, it should be mentioned, however, that the invention can also in principle operate using different optical inspection processes, for example by means of a through-lighting process with a light source and a camera. 
     An ejector pin  33  is arranged underneath the lower parts  28  of the holding segments  22  for each holding hole  23  and aligned with the holding holes  23 , which ejector pin  33  can be moved up and down as indicated by the double-headed arrow  34 , and is aligned with an aperture hole  29  in the lower part  28 . A feed element  35  which is tubular or in the form of a shaft is associated with each holding hole  23 , above and aligned with the holding holes  23  in the holding segments  22 . The longitudinal axis of the feed element  35  is aligned essentially vertically and, at its end facing the holding segment  22 , in each case has a respective clamping piece  36  for each holding hole  23 , which prevents the lowest capsule c from falling out of the feed element  35  back in the direction of the holding hole  23 . 
     The X-ray radiation source  31  emits an X-ray radiation lobe  38 , which can be detected by means of a detector  40 , which records and/or processes images, operates in particular digitally, is in the form of an X-ray large-area-sensor and is located on the opposite side of the capsule c to the X-ray radiation source  31 . 
     In order to prevent disturbances in the detection of the X-ray radiation lobe  38  in the area of the detector  40  by the feed element  35 , the feed element  35  is designed with suitable measures (for example by means of a plastic design) to allow X-ray radiation to pass through in the area of the X-ray radiation lobe  38 , and it is intended to be expressed by the dashed-line representation of the feed element  35  in the area of the X-ray radiation lobe  38 . Furthermore, according to the invention, it is important that the clamping piece  36  and the feed element  35  are arranged with respect to the X-ray radiation lobe  38  such that, as is shown in  FIG. 2 , a capsule c is located completely in the radiation lobe  38  when the lowest of the capsules c, which are positioned one above the other as a row, is held by the clamping piece  36 . An appropriate optic and/or an appropriate arrangement (separation) of the feed element  35  with respect to the X-ray radiation source  31  furthermore ensure that, as far as possible, the X-ray radiation lobe  38  does not cover any areas of capsules c below or above the capsule c that is currently being X-rayed. If this nevertheless were to occur, for example because of tolerances in the length of the capsules c, then, if appropriate, this can be compensated for by appropriate software in the evaluation device  47 , which will be mentioned further below. According to the invention, the feed element  35  is arranged with respect to the X-ray radiation source  31  and with respect to the X-ray radiation lobe  38  such that the X-ray radiation lobe  38  passes through the capsule c at right angles to its longitudinal axis  15 , which means that the detector  40  can record an image corresponding to a longitudinal section through the capsule c. 
     The detector  40  and the X-ray radiation source  31  are designed and arranged such that a plurality of capsules c, which are arranged alongside one another at one level, can each be X-rayed by them at the same time, and the X-ray radiation lobe  38  can be detected by the detector  40 . 
     In the exemplary embodiment illustrated in  FIGS. 1 and 2 , five capsules c are in each case arranged in a row in the holding segments  22 . The sensor apparatus  30  can therefore be used to simultaneously examine all five capsules c in each case in one test step during a phase when the capsules c are stationary in the feed element  35 . 
     A segregation device  42  is arranged above the feed element  35 . The segregation device  42  comprises a separately controllable segregation flap  43  for each of the feed elements  35 , which segregation flap  43  is mounted such that it can pivot on an axis  44  and, depending on the position of the segregation flap  43 , segregate individual capsules c in the direction of a good shaft  45  and a bad shaft  46 . 
     The sensor apparatus  30  which has been described so far for the capsule filling and closing machine  100  operates as follows: the feed wheel  21  transports the holding segments  22  cyclically below the area of the sensor apparatus  30 . In a phase when the feed wheel  21  is stationary, the capsules c which are located in the holding segment  22  are pushed synchronously by means of the ejector pins  33  out of the holding holes  23  in the lower part  28  of the holding segment  22 , upwards in the direction of the feed elements  35 . In the process, the capsules c which have in each case been pushed out previously still each rest on the clamping pieces  36  and, when subsequent capsules c are pushed in, are shifted further upwards by touching contact between the capsules, by one capsule length in each case. Because of the geometry of the feed elements  35 , capsules c are each still located exactly within the X-ray radiation lobe  38  of the X-ray radiation source  31 . During a phase in which the feed elements  35  are stationary, that is to say when no capsules c are currently being pushed over into the feed element  35  at an instant, the detector  40  in each case records an image of the capsules c which are located within the X-ray radiation lobe  38 , and supplies this to an evaluation device  47 . The evaluation device  47  allows digital evaluation and storage of the recorded image of the X-ray radiation lobe  38 . Once the evaluation device  47  has examined the recorded image for the desired characteristics, in particular with regard to the filling weight, any capsules c which have been identified as “bad capsules c” can be sorted out by means of the segregation device  42 . 
     By way of example,  FIG. 5  shows six different recordings  51  to  56 , recorded by a detector  40  alongside one another of capsules c filled with different filling materials and of different sizes. Different filling materials and different filling levels and arrangements of the filling materials in the capsules c can be seen in these recordings  51  to  56 . The evaluation program in the evaluation device  47  allows the sensor apparatus  30  to determine not only the respective filling weight of the capsule c, but also in addition to carry out further evaluations. By way of example, the status of the capsule casing (which means identification of defects in the capsule casing, such as cracks, fractures, pinches, deformations, etc.) may be mentioned. It is also possible to detect the state of the filling material, for example whether a pressed item is intact or has been destroyed, or whether a tablet is broken, etc. In principle, the capsule c can also be checked for the presence of the product. By way of example, this includes counting down tablets, microtablets or capsules in the capsule c, or their combinations. In principle, of course, it is also possible to identify capsules c which have not been filled or have been filled incorrectly. By way of example, mention should finally be made of the fact that the capsules c can also be examined for foreign bodies (in particular metal particles). In this case, it is particularly advantageous that the capsule c is detected completely, that is to say over its entire longitudinal extent, by the X-ray radiation lobe  38 , because of the arrangement and configuration of the feed elements  35 , without the capsules c in the process being concealed by parts of the feed elements  35  when lateral guides for the capsules c in the feed elements  35  may, for example, be composed of plastic. 
       FIGS. 3 and 4  show a modified sensor apparatus  30   a . In this case, holding segments  22   a  and lower parts  28   a  are provided which, in contrast to the holding segments  22 , have two rows  48 ,  49  of holding holes  23  for capsules c. As can be seen in particular from  FIG. 4 , six capsules c are in each case arranged within one holding segment  22   a  in each of the rows  48  and  49  in this case. In order nevertheless to make it possible to test the greater number of capsules c, in comparison to the holding segment  22 , in a single test step, provision is made for the capsules c to be pushed over into the individual feed elements  35  by means of a funnel-shaped distributor  50 , such that all twelve capsules c are arranged alongside one another on one plane, as can be seen in particular in  FIG. 4 . Because of the relatively large area of the capsules c which are arranged alongside one another, it may be necessary to use a plurality of X-ray radiation sources  31   a ,  31   b  as well as a plurality of detectors  40   a ,  40   b , which are arranged at right angles to the plane of the drawing in  FIG. 3 . 
       FIG. 6  shows a capsule monitoring apparatus  100   a . The capsule monitoring apparatus  100   a  may in this case be a component of an already described capsule filling and closing machine  100 , or may be operated as a separate monitoring apparatus  100   a . A filling material container  60  with capsules c which have already been filled and closed is provided for the capsule monitoring apparatus  100   a . The capsules c are separated from the filling material container  60  by means of a slide  61  which can be moved up and down, and are supplied to the feed element  35   a  in a row (or else in a plurality of rows arranged at right angles to the plane of the drawing in  FIG. 6 ). A sensor apparatus  30   b  is arranged under the filling material container  60 , the function of which sensor apparatus  30   b  has already been explained within the description of the capsule filling and closing machine  100  as shown in  FIGS. 1 to 5 . In particular, the sensor apparatus  30   b  can be used to detect the filling weight and possible damage to and contamination of the capsules c. 
     A blocking latch  62  is provided under the sensor apparatus  30   b  on the feed element  35   a  and in each case releases a capsule c which has previously been examined in the area of the sensor apparatus  30   b , or blocks it. Following the blocking latch  62 , the feed element  35   a  has a curved section  63  at whose outlet, and aligned with it, a weighing cell  64 , which is arranged in suspended form, is arranged. The weighing cell  64  is a component of a weighing device  65 , whose exact design and method of operation has already been explained in detail in DE 198 19 395 C1, from the same applicant, and to which reference is therefore made. 
     In particular, the weighing device  65  has an impeller wheel  66  which is moved in steps in the counterclockwise direction and with whose aid one capsule c is in each case fed into the area of the weighing cell  64 , and out of it. The weighing device  65  is followed, via a further curved area  67 , by an additional ejection device  68 , which has a moving flap  69 . The flap  69  makes it possible to separate good capsules c from bad capsules c depending on the result of the evaluations, in the area of the sensor apparatus  30   b  and of the weighing device  65 . 
     In addition, it should be mentioned that the capsule monitoring apparatus  100   a  can also be modified such that no filling material container  60  is provided. In this case, the weighing device  65  follows the sensor apparatuses  30  and  30   a , as shown in  FIGS. 1 to 3 , and is connected thereto. In other words, this means that a dedicated, separate impeller wheel  66  can be provided for each of the feed elements  35   a , with the weighing device  65  then likewise having a dedicated weighing cell  64  for each feed element  35   a.    
       FIG. 7  shows a sensor apparatus  30   c , which has once again been modified in comparison to  FIGS. 3 and 4 . In the sensor apparatus  30   c , a reference object  70  is arranged on each of the two opposite sides in the beam path of the X-ray radiation source (which is not illustrated). Two (identical) reference objects  70  are arranged with a view to in each case detecting and checking six capsules c, in each case by means of a detector  40   a ,  40   b . A reference object  70  is therefore associated with each detector  40   a ,  40   b . An important factor in this case is that, when using X-rays, the reference object  70  consists of a material which is as similar as possible to the atomic composition of the material to be analyzed, that is to say the material of the capsule c and the capsule content. Furthermore, provision is advantageously made for the reference object  70  to be in the form of a wedge or step. In this case, the reference object  70  is arranged such that the height of the reference object  70 , which is in the form of a wedge or step, varies in the direction in which the radiation from the X-ray radiation source  31  passes through. A further important factor is that the attenuation of the X ray radiation by the reference object  70 , at least in one area of the reference object  70 , is greater than the greatest attenuation caused by the capsule c (this is dependent on the density, the atomic composition and the thickness of the filling material and capsule c through which the radiation passes). Furthermore, the attenuation of the X-ray radiation by the reference object  70  at another point or on another area of the reference object  70  must be less than the smallest attenuation caused by the capsule c. In this case, any desired number of steps may be implemented between the two attenuation areas mentioned by the reference object  70  being in the form of a wedge or step.  FIG. 8  shows two images  72 ,  73 , which have been detected by means of two detectors  40   a ,  40   b  and are fed to the evaluation device  47 , with one reference object  70 , which is in the form of a step or staircase, being used in each case. 
     In order to adjust the detectors  40   a ,  40   b , it is necessary to be able to remove the reference object  70  from the image  72 ,  73 . Furthermore, it is essential that the position and orientation of the reference object  70  does not change during operation of the sensor apparatus  30   c . For starting up, the X-ray camera system, consisting of the X-ray radiation source  31 ,  31   a  and  31   b  and the detector  40 ,  40   a  and  40   b , is first of all adjusted without the reference object  70 . A reference object  70  and an object to be measured, that is to say a capsule c, are then measured and an image  72 ,  73  is recorded. This image  72  or  73  is stored. Radiation is then optionally passed through a second object to be measured and a second capsule c to be measured, and an image  72 ,  73  is recorded and stored. The capsule c is then located in the image  72 ,  73 . The grayscales of the reference object  70  are read and are linked or related to the actual geometric dimensions of the reference object  70 . The object to be measured, that is to say the capsule c to be measured, is then located in the image  72 ,  73 , and its information (for example individual grayscale values, area of the object on the image, etc.) is read by means of the evaluation device  47  from the image  72 ,  73 . This object information (for example grayscale values) is converted pixel-by-pixel to a virtual thickness, to be precise using the information from the reference object  70 . The mean value of these virtual individual thicknesses within the selected area can now be associated with the actual gravimetric weight of the capsule c, which was determined using a gravimetric weighing device. The reference object  70  is then located in the second image  72 ,  73 . The grayscales of the reference object  70  are likewise read and are compared with the grayscale values of the reference object  70  from the first image. If the grayscale values of the (second) reference object  70  are within a defined limit, the second recorded image  72 ,  73  is not corrected. If there is a change in the information, for example the grayscale values of the second reference object  70  outside defined limits, the image  72 ,  73  is appropriately corrected. The object (capsule c) to be measured is then located analogously to the manner in the first image  72 ,  73 , and its information is read from the image  72 ,  73 . In this case as well, the object information is then converted pixel-by-pixel to a virtual thickness, to be precise with the aid of the information from the reference object  70 . The mean value of these virtual individual thicknesses can now be associated with the actual gravimetric weight of the measurement object. If a third object to be measured and a third capsule c to be measured as well as the reference object  70  are now inserted into the X-ray camera system, the system is able to use the information from the two images  72 ,  73 , the reference object  70  and the gravimetric weights from the first two weighing processes to determine the weight of the third object (and of any desired number of further objects). 
     The capsule filling and closing machine  100  described so far and the capsule monitoring apparatus  100   a  can be modified in many ways. However, it is essential to the invention that the radiation sources are arranged with respect to the containers which pass through radiation such that radiation is passed through them at right angles to their longitudinal direction.