Abstract:
A system for producing and transporting portions of food includes a filling machine for continuously transporting a stream of food, a separating device for dividing portions from the transported food stream, and a transport device for delivering the portions to a subsequent processing device. To prevent fluctuations in portion size and weight, the system further includes a sensor unit for generating a portion request signal in response to a portion request from the subsequent processing device. The sensor unit outputs the portion request signal to the filling machine, which is designed to control the continuous transportation of the food stream using the portion request signal. The system is operable to synchronize the entire line, including the filling machine, the separating device, the transport device, and the subsequent processing device.

Description:
TECHNICAL FIELD 
     The present invention relates to a system and a method for producing and transporting food portions, and more specifically, to a system including a filling machine for continuous transportation of a stream of food. 
     BACKGROUND 
     Food portions are frequently produced as follows: A food supply is stored in a filling machine, and is dispensed from the filling machine to a cut-off device. The cut-off device divides the stream of food delivered by the filling machine into individual portions and delivers these portions to a conveyor belt or other transport apparatus. The conveyor belt transports the food portion to a subsequent processing device, which packages or reshapes the food portion or carries out other work steps thereon. 
     Various designs, interactions, and methods of operation of the individual components are known. The filling machine, for example, can operate in a start-and-stop mode, i.e., the filling machine starts to deliver the stream of food in response to a portion request signal and stops delivery of the stream of food in response to the end of the portion request signal. In another example, such a filling machine may issue a cutting signal to the cut-off device, whereupon the cut-off device separates the stream of food at the end of the portion. Such a method of operation is referred to as a discontinuous system because the filling machine starts and stops its operation according to the portion request signal. 
     Another system is also known in which the filling machine delivers the stream of food continuously, without changing a filling speed. An external portion request signal is received by the cut-off device, which divides the stream of food into individual portions in response to the portion request signal. To this end, the portion request signal also functions as the cutting signal. 
     Still another known system includes a higher-level controller that controls the food delivery sequence. In this system, the higher-level controller issues a filling speed signal to the continuously operating filling machine and a cutting signal to the cut-off device. The higher-level controller thus determines the operation of both the cut-off device and the filling machine simultaneously. 
     An exemplary  100  system having a higher-level controller  147  is depicted in  FIG. 5 . The path of the food portions in the system  100  is as follows: a dough or a mass of meat is fed to a dough divider or knife  120  and is divided into individual portions by the knife  120 . The shaping belt  130  receives the divided dough portions from the knife  120 , shapes the portions, and delivers the portions to a chute or flouring device  141 . From the flouring device  141 , the shaped portions are then delivered to a rotary gate  142 , which delivers the shaped portions to a proofing conveyor (also referred to as proofer)  143 . The dough shapes are transported from the proofer  143  to a baking sheet  144  and deposited on the baking sheet  144 . The dough shapes are then delivered from the baking sheet  144  to a proofing cabinet  145  and then to an oven  146 . 
     The signal control by the higher-level controller  147  of the system  100  of  FIG. 5  is as follows: measurement data “D” from the knife  120  and the proofer  143  are input into the controller  147 . On the basis of these entered data D, the controller  147  calculates signals which are then issued to the knife  120  and the proofer  143 , as well as to the rotary gate  142  and to the flouring device  141   
     In the exemplary embodiment of the system  100  shown in  FIG. 5 , the dough is fed continuously. Thus, the portion request signal issued by the controller  147  corresponds to the cutting signal. In this regard, the portion size is determined by the cut-off timing, which is actuated by the controller  147  to the knife  120 . The portion request signal is referred to as “A” and the cutting signal is referred to as “B.” As shown in  FIG. 5 , the portion request signal A is equivalent to the cutting signal B. 
     The known devices have various disadvantages. When portioning some products (dough, for example), greater weight fluctuations in the portions result when the filling machine is accelerated and slowed for each portion compared to when the portioning is done (for example by cutting) during continuous operation of the filling machine. However, if continuously operating machines in a line define the moment when portions are produced in order for the line to work optimally, that operation results in a contradiction of competing interests. On the one hand, the filling machine must transport at the most constant possible speed for exact portioning of a certain number of portions, yet on the other hand, subsequent components on the line specify whether 99 or 101 portions per minute are needed at that moment as the certain number of portions. 
     As explained above, other systems are known in which the filling machine is started by an individual signal for each portion, whereupon the filling machine transports the set portion size and then stops again. The separating of the portions takes place at the end of each portion. Such a system has the disadvantage that the starting and stopping operation may result in poor weight precision for the portions. 
     Also mentioned above are other systems that transport food at a velocity wherein continuous transporting is possible without readjusting the velocity. The separating of the portions in such systems takes place at the cut-off device, controlled by time to cut periodically or by a signal. Such systems have the disadvantage that the portioning yield of the line may drop during operation, for example, from 101 to 99 portions per minute because of fluctuations in the power grid. As a result, the portions are either too heavy or the production is interrupted by a malfunction. 
     The object of the invention is to address these and other disadvantages of the systems and methods known in the existing art for producing and transporting food portions. 
     SUMMARY OF THE INVENTION 
     According to the invention, a system for producing and transporting food portions is proposed. The system includes the following: a filling machine for continuously transporting of a stream of food, a separating device for separating food portions from the transported stream of food, a transporting device for transporting the portions to a subsequent processing device, and a sensor unit for generating a portion request signal on the basis of a portion request from the subsequent processing device. The sensor unit issues the portion request signal to the filling machine, which controls the continuous transporting of the food stream according to the portion request signal. Line synchronization is achieved by the system 
     A signal which originates at the subsequent processing machine reports to the filling machine when portions are to be produced. This signal is a portion request signal for the continuously operating filling machine. The disadvantages of discontinuous operation of the filling machine, including rapid wear and high waste of food, are avoided by using the continuously operating filling machine. Fluctuations in the power grid leading to fluctuations of portions per minute can also be evened out because the machines run synchronously. More specifically, the filling machine is synchronized with the subsequent processing device. 
     Preferably, the filling machine is also designed to generate a separating signal in response to receiving the portion request signal. The filling machine issues the separating signal to the separating device, which then separates the portions in response to the separating signal. Such a system offers the advantage that the line synchronization of the filling machine and the subsequent processing device also extends to the separating device. Because the separating device is operating synchronously with the filling machine, the size and weight of the portions are as constant as possible and fluctuations in portion size and weight are reduced or prevented. 
     Preferably, at least one of the portion request signal or the separating signal is a timing signal. A timing signal as used in this description is a signal which includes a frequency that determines the working cycle of the filling machine or the separating device. The timing signal is a square-wave signal, alternating between a logical “1” value and a logical “0” value. As used in this description, the “timing signal” can also be a triangular signal, saw tooth signal, or any other signal that is suitable for determining the working cycle of at least one of the filling machine and the separating device. 
     Preferably, one cycle of the timing signal represents at least one of the request of one portion or the separation of one portion. Alternatively, one cycle of the timing signal represents at least one of the request or the separation of two portions. In another example, two cycles of the timing signal represent at least one of the request or the separation of one portion. In this regard, any combination of the ratio of number of a cycles of the timing signal to requests and/or separations of a number of portions is possible within the scope of the invention. The possibility of setting the ratio of portions to signals has the advantage that imprecisions in the signal sequence (i.e., jitters) can be compensated for, by setting, for example, three portions per three signals instead of one portion per one signal. 
     Preferably the filling machine has a control unit to control both the continuous transportation of the food stream according to the portion request signal, and the generation of the separating signal in response to the portion request signal. Such a control unit in the filling machine offers the advantage that no higher-level controller is necessary. To this end, the system for producing and transporting food portions can be simplified such that the disadvantages of the higher-level controller are avoided. The system is inherently synchronous, without having to rely on an external control unit. Therefore, the system provides simple and reliable line synchronization according to the invention. 
     Preferably the control unit of the filling machine is designed to synchronize the separating signal with the portion request signal. This operation offers the advantage that the separating device is constantly synchronized with the filling machine. 
     Preferably the control unit is designed to calculate a mean value for the cycle lengths of the portion request signal. The control unit is also designed to control the continuous transportation of the food stream by the filling machine according to the mean value. The control unit is also configured to generate the separating signal using the mean value. The signals or cycle lengths are preferably processed algorithmically (e.g., by taking the mean value), and are used as the basis for the speed of the filling machine and for the timing the separating signal. In that way, high precision is attained by transporting the food at nearly constant speed, and adaptation to slight fluctuations in the positioning performance of the line is also made possible. Although the filling machine transports continuously, the situation is prevented in which a different number of portions is produced than was requested by the downstream system. 
     Preferably the control unit is designed to stop the operation of the filling machine and the separating device if no clock cycle is received for a certain time. Consequently, a production backup or empty line can be prevented. 
     Preferably the system also includes a filling stream divider. The filling stream divider is operable to divide the food stream or the food portions (i.e., before or after the separating device) into a plurality of parallel food streams or food portions transported synchronously on the transport device. 
     Preferably the subsequent processing device is designed to shape and package the portions. Other subsequent processing device designs are also possible within the scope of the invention, such as a chute or flouring device, a shaping belt, a rotary gate, a proofing conveyor, a baking sheet, a proofing cabinet, or an oven. 
     Preferably the filling machine is a vacuum based filling machine. Preferably the separating device includes a knife or scraper. Other designs of the separating device are also possible within the scope of the invention. 
     In another aspect, the invention relates to a filling machine for continuous transportation of a stream of food and for use in the system described above. The filling machine is designed to control the continuous transportation of the stream of food according to a portion request signal. 
     In still another aspect, the invention relates to a method for producing and transporting food portions. The method includes these steps: transporting of a stream of food continuously, separating portions from the transported stream of food, transporting the portions to a subsequent processing device, generating a portion request signal on the basis of a portion request from the subsequent processing device, and controlling the continuous transporting of the stream of food using the portion request signal. 
     Preferably the method further includes generating a separating signal using the portion request signal, and separating the portions using the separating signal. Preferably the method also includes synchronizing the separating signal with the portion request signal. 
     Preferably the method further includes calculating a mean value from the cycle lengths of the portion requesting signal, controlling the continuous transporting of the food stream according to the mean value, and generating the separating signal using the mean value. 
     Preferably the method also includes stopping the continuous transporting and separating if no clock cycle of the portion request signal is received for a certain time. Preferably the method further includes shaping and packaging the portions in the subsequent processing device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The system will be explained below on the basis of exemplary embodiments illustrated in the following figures. 
         FIG. 1  is a schematic view of the system according to one embodiment of the invention. 
         FIG. 2  is a view of a signal scheme used with the system of  FIG. 1 . 
         FIG. 3  is a view of a signal scheme used with the control unit of the filling machine of the system of  FIG. 1 . 
         FIG. 4  is a schematic view of another embodiment of the system according to the invention. 
         FIG. 5  is a schematic view of a conventional system for producing and transporting food portions. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates schematically a system  200  according to one embodiment of the invention for producing and transporting food portions. The system  200  includes a filling machine  10  for continuously transporting a food stream. The system  200  also includes a separating device  20 , which is designed to separate portions from the transported food stream. The system  200  further includes a transporting device  30  for transporting the portions to a subsequent processing device  40 . The transporting device  30  is preferably a conveyor belt. The system  200  also includes a sensor unit  50  designed to generate a portion request signal A on the basis of a portion request produced by the subsequent processing device  40 . The sensor unit  50  issues the portion request signal A to the filling machine  10 . The subsequent processing device  40  may include a device for packaging the individual portions. 
     To ensure that every one of the packages  48 , indicated schematically in  FIG. 1  by semicircles on subsequent processing device  40 , is filled, the subsequent processing device  40  serves as a so-called “master” to generate the portion request signal A. During operation, an empty package  48  carried by the subsequent processing device  40  and the portion being transported by the conveyor belt  30  to the location to fill the package  48  are synchronized by the sensor unit  50 . To this end, the sensor unit  50  measures the position of the empty package  48  and generates the portion request signal A on the basis of the measurement to synchronize the delivery of a portion into the empty package  48 . 
     Based on the generated portion request signal A from the sensor unit  50 , which may be located at the end of the transport device  30  or at the subsequent processing device  40 , the line is synchronized with the filling machine  10  or the separating device  20 . It is preferred that the sensor unit  50  generates the portion request signal A in response to the transfer of a portion from the transport device  30  to the subsequent processing device  40 . 
     The sensor unit  50  can be designed to determine the weight and the size of the portion that is being transported by the transport device  30 , and to synchronize the line with the filling machine  10  or the separating device  20  accordingly. The filling machine  10  controls the continuous transporting of the food stream on the basis of the generated portion request signal A, thereby achieving the line synchronization according to the invention. 
     Preferably, the filling machine  10  generates a cutting or separating signal B, which is issued to the separating device  20 , in response to the portion request signal A. Because the separating signal B is generated in the filling machine  10  on the basis of the portion request signal A, the operation of the filling machine  10  and the separating device  20  are synchronized with each other, enabling fluctuations in portion size or weight to be evened out. 
       FIG. 2  illustrates an overview of the signals of the sensor unit  50 , the filling machine  10 , and the separating device  20 . The signals of the sensor unit  50  and the filling machine  10  are illustrated as square-wave timing signals. Timing signals of any other shape are equally possible within the scope of the invention, however. The square-wave signal is shown in  FIGS. 2 and 3  to explain the frequency of the working cycle of the filling machine  10  and of the separating device  20 . As illustrated in  FIG. 2 , the maximum value of the timing or square-wave signal is designated with a logical 1 and the minimum value with a logical 0. 
     The sensor unit  50  generates the portion request signal A, which serves as the master signal for the portioning cycle. According to the invention, the master signal is then passed to the line by the sensor unit  50  or the subsequent processing device  40 . As shown in  FIG. 2 , the clock cycle or cycle length of the portion request signal A may vary. Such a fluctuation or change in the clock cycle of the portion request A signal may be caused unintentionally, for example by power fluctuations in the power grid, or intentionally, for example by portion size or weight rearrangement. 
     The filling machine  10  receives the portion request signal A from the sensor unit  50  and in response, generates the cutting signal B.  FIG. 2  illustrates how the filling machine  10  or a control unit  60  of the filling machine  10  evens out the fluctuation in the portion request signal A. To this end, a mean value is calculated from the fluctuating or changing cycle lengths of 480 ms and 520 ms of the portion request signal A, and this calculated signal cycle mean value controls the issuance of cutting signal B to the cut-off device  20 . 
     The signal of the cut-off device  20  in  FIG. 2  represents the operation of the knife drive, which is variable between 0% and 100% in order to divide the food stream into individual portions. The knife drive is controlled by the clock cycle or the cycle length of the cutting signal B. More specifically, at each actuation of the cutting cycle signal B, the knife drive is operated from 0% to 100% in order to effect a separation of a portion from the food stream. Synchronization of the portion request signal A, the cutting signal B, and the knife drive is thus achieved, and synchronization of the line caused by synchronization of the signals substantially prevents fluctuation in portion size or weight. 
       FIG. 3  shows another signal scheme, in which the control operation within the filling machine  10  is depicted in greater detail. The sensor unit  50  specifies the master signal for the portioning cycle in the form of portion request signal A. The portion request signal A preferably alternates between a logical value of 0 (inactive) and a logical value of 1 (active).  FIG. 3  depicts a situation where the clock cycle of the portion request signal A is shortened from 480 ms to 470 ms such that a change occurs in the tempo of the portion request signal A. 
     The filling machine  10  or the control unit  60  of the filling machine  10  receives the portion request signal A as an input IN. The control unit  60  initially detects a cycle length of 480 ms, until the tempo change to 470 ms occurs. Upon detecting the tempo change, control unit  60  undergoes a change processing, in order to synchronize the filling machine  10  and the cut-off device  20  with the tempo-modified portion request signal A. To that end, the control module  60  issues modified signals at an output OUT, which adjust the velocity of the conveyor drive (mean signal pattern of the schematic filling machine  10  of  FIG. 3 ) and the timing of the cutting signal B to correspond to the tempo-modified portion request signal A. 
     The conveyor drive velocity is variable between 0% and 100%. In the illustrated example of  FIG. 3 , a portion is to have a weight of X grams. The conveyor drive is actuated so that X grams of the food stream are delivered from the filling machine  10  within the cycle length of the portion request signal A, in order to be separated by the cut-off device  20  into a portion weighing X grams. If the time interval of the portion request signal is lowered, as shown in the example in  FIG. 3 , the conveyor drive receives the signal from the control unit  60  to increase velocity accordingly, so as to continue transporting the predefined weight of X grams in the shorter time of 470 ms. The control unit  60  controls the conveyor drive so that a transition cycle (highlighted by arrows  62 ) is used after the tempo change from 480 to 470 ms to undergo a change processing and adjust the transport performance of filling machine  10  to the new tempo. 
     While undergoing the change processing, the output (the conveyor tempo) is higher for one portion length than for the new portioning cycle, so that the portion delivered during the change processing has the same weight as all other portions. After the change processing, the portion request signal A and the cutting signal B are again synchronized with each other. In the illustrated example, each signal corresponds to one portion. Alternatively, a different relationship of signal to portion may be chosen, so that for example (at a setting of “212”) every second portion request is ignored and the corresponding cutting signal is calculated as the mean between the signals. The signals may also be dependent not only on the number of portions, but on the “tolerance,” as well as other known parameters and algorithms. 
     As previously explained in reference to  FIG. 2 , the cutting signal B is synchronized with the portion request signal A by being generated in response to portion request signal A. Consequently, fluctuations or changes in the portion request signal A are converted directly to a modified clock signal or cycle length of cutting signal B. In the example of  FIG. 3 , this conversion is accomplished by a short transition cycle of 460 ms, which synchronizes the cutting signal B with the portion request signal A as quickly as possible. 
     The cut-off device  20  divides portions from the food stream in response to the cutting signal B such that the knife drive is modifiable between 0% and 100%. As depicted in  FIG. 3 , the knife drive is actuated from 0% to 100% in response to the actuation of the cutting signal B. 
       FIG. 4  illustrates another embodiment of the system  300  according to the invention. In this embodiment the production line of  FIG. 4  is divided into a master portion  301  and a slave portion  302 . The master portion  301  corresponds essentially to a conventional system, such as the system  100  described above in reference to  FIG. 5 . The slave portion  302  includes the filling machine  10 . According to this embodiment, the filling machine  10  is operated in combination with the master portion  301  as described in further detail below. 
     The filling machine  10  includes a control unit  60 . The control unit  60  is preferably a graphics PC. The filling machine  10  preferably also includes a cooling system  80 , which keeps the food stream, or the food mass from which the food stream is formed, at an appropriate temperature. The food stream is output from the filling machine  10  to a filling stream divider (also known as a “water wheel”)  70 , which divides the food stream into a plurality of food streams. The food streams  70  are then output to the cut-off device  20 . The cut-off device  20  divides the food streams into portions and delivers these portions to the transport device or shaping belt  30 . The shaping belt  30  delivers the food streams to the chute or flouring device  41 , and from there to the rotary gate  42 . The rotary gate  42  transfers the portions to a proofing conveyor  43 , after which the portions are placed on a baking sheet  44  and are forwarded to a proofing cabinet  45  and an oven  46 . 
     The master portion  301  may optionally include a higher-level controller  47 , as explained earlier in reference to  FIG. 5 . The filling machine  10  is operated as described below. The rotary gate  42  operates as a subsequent processing device  40 . The rotary gate  42  includes recesses into which the portions are received. The rotary gate  42  could operate in the same way for example for shaping or packaging the portions. The rotary gate  42  includes the sensor unit  50 , which picks up the clock signal, for example, at the shaft of the rotary gate  42  in order to generate the portion request signal A. The portion request signal A is output by the rotary gate  42  or the sensor unit  50  and is delivered to the filling machine  10 . The control unit  60  of the filling machine  10  generates the separating signal B in response to the portion request signal A, and then outputs it to the cut-off device  20 . In this manner, line synchronization of the filling machine  10  and the cut-off device  20  with the subsequent processing device  40  is achieved. 
     In order to correct recurring deviations of the master signal (i.e., the portion request signal A), the system  300  can be instructed to respond only to every second or third signal cycle, by entering a so-called “2/2” or “3/3” mode. The skipped cycles are replaced by calculated (jitter-free) signals. The algorithm preferably uses two different methods for the synchronization: a first method defining very slight speed change and a second method with a temporary rapid jump to a substantially higher or lower speed. By preference, the first method is used. But if the mismatch between the external signal cycle (portion request signal A) and the cutting signal (B) is greater than a set “tolerance,” the second method is used. When inputting a value for the “tolerance,” the tolerance is limited depending on the current portion size/duration. 
     A “timeout” option of the control unit  60  preferably specifies how many external signal cycles of portion request signal A may be lacking before the filling machine  10  is stopped. 
     Preferably, at the start-up of the line, the control unit  60  or the filling machine  10  analyzes the external signal cycle of signal A for a predetermined length of time before operation of the system  300  or the filling machine  10  begins. During this analysis, the tempo of the filling machine  10  and the portions per signal are determined.