Combined metering device

Abstract

A combination weighing device repeatedly performs the following cycle: feeding articles to multiple weighing hoppers for weighing, determining a combination of the multiple weighing hoppers based on multiple weighing values, selecting a combination close to a target weight value from the determined combinations, and discharging articles from the multiple weighing hoppers associated with the selected combination. The combination weighing device comprises: a storage unit that stores a time series of weighing values ​​successively acquired from the weighing hoppers; a time measurement unit that measures, when the time series of weighing values ​​stored in the storage unit converges into a region deemed stable, the time elapsed from the time corresponding to the feeding of articles to the weighing hoppers to the time when the time series of weighing values ​​enter the region deemed stable, as a stabilization time until the weighing values ​​stabilize; and a selection unit that can acquire the stabilization time using the time measurement unit over multiple cycles and select a recommended stabilization time that can maintain a specified weighing accuracy based on the standard deviation of the acquired stabilization times over the multiple cycles.

Description

Technical Field

[0001] One aspect of the present invention relates to a combination metering device. Background Art

[0002] There is known a combination metering device that repeatedly performs the following cycle: articles are supplied to a plurality of metering hoppers for metering, a combination of a plurality of metering hoppers is determined based on the plurality of measured values ​​obtained, a combination close to a target weight value is selected from the determined combinations, and articles are discharged from a plurality of metering hoppers associated with the selected combination. In such a combination metering device, a stabilization time is set as one of the action moments until the metering value stabilizes. Furthermore, for example, the stabilization time from the moment the article is supplied to the metering hopper until the metering value stabilizes is measured, and when the stabilization time has elapsed, the metering value of the metering hopper is obtained. The stabilization time is usually set according to the capacity of the combination metering device. Therefore, for example, in the combination metering device described in Japanese Patent Application Laid-Open No. 9-113348, the stabilization time is found by obtaining the waveform of the time series of metering values ​​obtained successively by the metering hoppers and displaying it on a measuring device, etc., and then set in the device. Summary of the Invention

[0003] However, in the aforementioned combination weighing device, depending on the type of item, the fed items may sometimes bounce around in the weighing hopper. Consequently, the stabilization time is not always appropriate, and the measured value obtained after the stabilization time has elapsed may not match the actual weight of the item. In such cases, the stabilization time must be adjusted, but such adjustments often rely on experience and intuition.

[0004] Therefore, one aspect of the present invention is to provide a combination metering device that can set an appropriate stabilization time without relying on experience or intuition.

[0005] A combination weighing device according to one aspect of the present invention repeatedly performs the following cycle: feeding articles to a plurality of weighing hoppers for weighing, determining a combination of the plurality of weighing hoppers based on the plurality of obtained weighing values, selecting a combination close to a target weight value from the determined combinations, and discharging articles from the plurality of weighing hoppers associated with the selected combination, the combination weighing device comprising: a storage unit for storing a time series of weighing values ​​successively obtained by the weighing hoppers; a time measuring unit for measuring, when the time series of weighing values ​​stored in the storage unit converge into a region considered stable, the time elapsed from the time corresponding to the feeding of the articles to the weighing hoppers to the time when the time series of weighing values ​​entered the region considered stable, as a stabilization time until the weighing values ​​stabilize; and a selection unit for obtaining the stabilization time by the time measuring unit in a plurality of cycles and selecting a recommended stabilization time based on a standard deviation of the obtained stabilization times in the plurality of cycles, the recommended stabilization time being a stabilization time capable of maintaining a specified weighing accuracy.

[0006] This combined weighing device can obtain the stabilization time, which varies each time items are added to the weighing hopper, over multiple cycles. Based on the standard deviation derived from the statistical data of the obtained stabilization times, a recommended stabilization time that maintains the specified weighing accuracy is selected. This allows the appropriate stabilization time to be set without relying on experience or intuition.

[0007] In a combined metering device according to one aspect of the present invention, a time measurement unit calculates convergence values ​​of time-series metering values ​​stored in a storage unit over multiple cycles and determines a region of a certain width based on the convergence values ​​of each cycle as a stable region. This allows specific determination of a region considered stable.

[0008] In a combination metering device according to one aspect of the present invention, a time measurement unit tracks time-series meter values ​​stored in a storage unit retroactively to determine the time when the time-series meter values ​​enter a region considered stable. This allows for specific determination of the time when the time-series meter values ​​enter a region considered stable.

[0009] In a combination metering device according to one aspect of the present invention, the selection unit includes a display unit that displays a bar graph of stabilization times for a plurality of cycles and also displays the recommended stabilization time on the bar graph. This allows the recommended stabilization time to be easily confirmed on the display unit.

[0010] In the combination metering device according to one aspect of the present invention, the recommended stabilization time is the time obtained by adding a time equivalent to twice the standard deviation to the average of the stabilization times obtained for a plurality of cycles. In this case, an appropriate stabilization time can be specifically set.

[0011] In a combination weighing device according to one aspect of the present invention, the time corresponding to the supply of articles to a weighing hopper is related to at least one of the closing time of an article discharge gate in the weighing hopper, the opening time of an article discharge gate in the weighing hopper, and the opening time of an article discharge gate in a supply hopper that supplies articles to the weighing hopper. In this case, the starting point of the stabilization time can be a time related to any one of the closing time of the article discharge gate in the weighing hopper, the opening time of the article discharge gate in the weighing hopper, and the opening time of the article discharge gate in the supply hopper. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic configuration diagram of a combination metering device according to an embodiment.

[0013] Figure 2 Yes Figure 1 A diagram showing the functional structure of the control unit.

[0014] Figure 3 Yes Figure 1 A flowchart of an example of processing based on a control unit.

[0015] Figure 4 This is a graph showing an example of stabilization time.

[0016] Figure 5 A diagram showing a display example of a touch panel display. DETAILED DESCRIPTION

[0017] Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings. In addition, in each figure, the same or corresponding parts are marked with the same reference numerals, and repeated descriptions are omitted.

[0018] like Figure 1 As shown, the combination weighing device 1 includes a feeding trough 2, a dispersed feeder 3, multiple radial feeders 4, multiple pool hoppers (supply hoppers) 5, multiple weighing hoppers 6, a collecting trough 8, a timing hopper 9, a weighing unit 11, a control unit 20, and an interface 30. The combination weighing device 1 repeatedly performs the following cycle: articles M are fed to the multiple weighing hoppers 6 for weighing, combinations of the multiple weighing hoppers 6 are determined based on the weight values ​​of the individual articles in the multiple weighing hoppers 6, a combination of articles M that is close to a target weight value is selected from the determined combinations, and the articles are discharged from the multiple weighing hoppers 6 associated with the selected combination.

[0019] The combination weighing device 1 weighs the articles M supplied by the conveyor 50 to a target weight and supplies the articles M to the bag-making and packaging machine 60. The conveyor 50 is an external device that supplies the articles M to the combination weighing device 1. The articles M may be agricultural products, marine products, processed foods, or other items whose individual quality may vary.

[0020] The feed chute 2 is located below the conveying end 50a of the conveyor 50. The feed chute 2 receives articles M dropped from the conveying end 50a of the conveyor 50 and discharges them downward. The disperser feeder 3 conveys articles M supplied from above toward the periphery. The disperser feeder 3 is located below the feed chute 2. The disperser feeder 3 vibrates with an electromagnetic vibrator, thereby conveying articles M on the conveying surface 3a toward the periphery.

[0021] The radial feeders 4 further radially convey the articles M conveyed from the dispersed feeder 3. The radial feeders 4 are radially arranged along the outer edge of the conveying surface 3a of the dispersed feeder 3. The radial feeders 4 convey the articles M by vibrating with an electromagnetic vibrator.

[0022] Multiple pool hoppers 5 are arranged around the vertical centerline CL. Each pool hopper 5 is located below the front end of the trough 4a of each radial feeder 4. Each pool hopper 5 has an openable and closable gate (article discharge gate) 5a. The gate 5a is located at the bottom of the pool hopper 5. By closing the gate 5a, each pool hopper 5 temporarily stores articles M discharged from the front end of the corresponding trough 4a. By opening the gate 5a, each pool hopper 5 discharges the temporarily stored articles M downward.

[0023] A plurality of weighing hoppers 6 are arranged around the center line CL. Each weighing hopper 6 is arranged below the gate 5a of each tank hopper 5. Each weighing hopper 6 has a main body 61 for storing articles M and a gate (article discharge gate) 62 that can be opened and closed at its bottom. The gate 62 is provided on the main body 61. The gate 62 is located at the bottom of the weighing hopper 6. Each weighing hopper 6 temporarily stores the articles M discharged from the corresponding tank hopper 5 in the main body 61 by closing the gate 62. Each weighing hopper 6 discharges the articles M temporarily stored in the main body 61 downward by opening the gate 62.

[0024] The collecting trough 8 collects the articles M discharged from each metering hopper 6 to the discharge port 8a. The discharge port 8a is located on the lower center line CL relative to the multiple metering hoppers 6. The collecting trough 8 has an upper trough portion 81 and a lower trough portion 82. The upper trough portion 81 receives the articles M discharged from each metering hopper 6 and slides the articles M toward the discharge port 8a side (i.e., the center line CL side and the lower side). The lower trough portion 82 is a truncated cone-shaped cylinder that is tapered downward and has an upper opening 82a and a lower opening 82b. The lower trough portion 82 uses the lower opening 82b as the discharge port 8a and discharges the articles M downward from the discharge port 8a.

[0025] The timing hopper 9 is located below the discharge port 8a. The timing hopper 9 has an openable and closable gate 9a. The gate 9a is located at the bottom of the timing hopper 9. When the gate 9a is closed, the timing hopper 9 temporarily stores the articles M discharged from the collecting chute 8. When the gate 9a is opened, the timing hopper 9 discharges the temporarily stored articles M into the bag making and packaging machine 60.

[0026] The weighing unit 11 is disposed within a housing 13 supported by a frame 12. The weighing unit 11 includes multiple load cells 11a. Each load cell 11a supports a corresponding weighing hopper 6. When items M are temporarily stored in each weighing hopper 6, the weighing unit 11 measures (acquires) the weight of each weighing hopper (a measured value corresponding to the mass of the items M). In this embodiment, the weighing unit 11 performs real-time (sequential) measurement in at least one of the multiple weighing hoppers 6, acquiring measured values ​​in a time series.

[0027] The control unit 20 is disposed within the housing 13. The control unit 20 includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The control unit 20 controls the operations of various components of the combined weighing device 1, including the conveying operations of the dispersed feeder 3 and the radial feeder 4, the opening and closing operations of the gates 5a of each pool hopper 5, the opening and closing operations of the gates 62 of each weighing hopper 6, and the opening and closing operations of the gates 9a of each time hopper 9. The control unit 20 is communicatively connected to the bag-making and packaging machine 60.

[0028] The control unit 20 associates and stores the weight values ​​measured by the weighing unit 11 with the weighing hoppers 6 storing the articles M corresponding to those weight values. From the multiple weight values ​​of the articles M measured by the weighing unit 11 and corresponding to the respective weighing hoppers 6, the control unit 20 selects a combination of articles M such that the total value reaches a target weight value. More specifically, the control unit 20 combines the weight values ​​of the individual articles M output by the respective weighing units 11 and selects a combination of articles M such that the total value of the combination approaches the target weight value and falls within a predetermined range. In other words, based on the weight values ​​of the individual articles M in the multiple weighing hoppers 6 obtained by the weighing unit 11, the control unit 20 calculates a combination of articles M that is equal to or close to a pre-set target weight value. The control unit 20 then causes the articles M to be discharged from the weighing hoppers 6 containing the articles M associated with the calculated combination.

[0029] The interface 30 is a device that receives information input from a user such as an operator. The interface 30 includes a touch panel display (display unit) 30t, such as a liquid crystal display. The interface 30 allows selection of a stabilization time (described in detail later) via the touch panel display 30t.

[0030] Next, the control unit 20 will be described in detail.

[0031] like Figure 2 As shown, the control unit 20 includes a storage unit 22, a time measurement unit 24, and a recommended stabilization time calculation unit 26. The control unit 20 includes the storage unit 22, the time measurement unit 24, and the recommended stabilization time calculation unit 26 as conceptual components that execute various control processes. This conceptual component is configured as software, for example, by loading a program stored in ROM into RAM and executing it on the CPU.

[0032] The storage unit 22 stores information related to the operation of the combination metering device 1. The storage unit 22 stores time-series measurement values ​​measured in real time by the metering unit 11 in the metering hopper 6. Time-series measurement values ​​are data representing measurement values ​​measured over time by the metering unit 11 during a period (e.g., three seconds) that includes at least one cycle repeated by the combination metering device 1. Time-series measurement values ​​are, for example, data represented by waveforms on a graph with time and measurement value as the horizontal and vertical axes. The storage unit 22 stores and accumulates time-series measurement values ​​for one or more metering hoppers 6 over multiple different periods. The storage unit 22 stores and accumulates a plurality of the aforementioned stabilization times.

[0033] The time measurement unit 24 starts timing from the time point when the metering value becomes unstable due to the mechanical vibration generated by the opening and closing of the gate of the metering hopper 6 or the pool hopper 5. The timing start time point in this case is, for example, the moment when the control unit 20 outputs a drive signal to the gate 5a, 62 of the pool hopper 5 or the metering hopper 6. From this moment on, the metering value of the metering hopper 6 is input successively and stored in the storage unit 22. The metering values ​​of the time series stored in the storage unit 22 converge to a fluctuation range that is considered to be within the stable area as time passes. The stable area in this case is an area of ​​a predetermined width. The time measurement unit 24 can obtain the convergence value of the metering value of the time series stored in the storage unit 22 in multiple cycles, and obtain an area of ​​a certain width based on the convergence value of each cycle obtained as the stable area. The time measurement unit 24 measures the time from the moment corresponding to the supply of the item M to the weighing hopper 6 to the moment when the measured value of the time series stored in the storage unit 22 converges into the stable area (the area considered to be stable) as the stabilization time until the measured value stabilizes.

[0034] The convergence value of each cycle depends on the supply amount of the article M supplied to the metering hopper 6 in each cycle. In addition, in the present embodiment, the fluctuation range that is considered to be within the stable area includes not only the fluctuation range when it is completely within the stable area, but also includes the fluctuation range when, for example, it momentarily exceeds the stable area but otherwise remains within the stable area. The fluctuation range is a prescribed upper limit value and a lower limit value based on the convergence value. In the present embodiment, the time corresponding to the supply of the article M to the metering hopper 6 is related to the time of opening the gate 5a in the pool hopper 5 that supplies the article M to the metering hopper 6. In addition, the time corresponding to the supply of the article M to the metering hopper 6 is not particularly limited, and may be a time related to the time of closing the gate 62 in the metering hopper 6, or a time related to the time of opening the gate 62 in the metering hopper 6.

[0035] The time measurement unit 24 tracks the time series of measured values ​​stored in the storage unit 22 retroactively over time to determine the time when the measured values ​​entered the stable region. For example, a measured value that is converging within a range of fluctuation considered to be within the stable region may actually experience a widening of the fluctuation over time. Therefore, when the measured values ​​that are converging within a range of fluctuation considered to be within the stable region intersect the upper or lower limit of the stable region through retroactive tracking, the time measurement unit 24 determines that the time point is the time when the measured values ​​enter the stable region.

[0036] The recommended stabilization time calculator 26 obtains stabilization times over multiple cycles using the time measurement unit 24 and stores the obtained stabilization times as statistical data in the storage unit 22. The recommended stabilization time calculator 26 calculates the standard deviation of the stabilization times over multiple cycles stored in the storage unit 22. Based on the calculated standard deviation, the recommended stabilization time calculator 26 calculates a recommended stabilization time that maintains the specified measurement accuracy. The recommended stabilization time is the average of the obtained stabilization times over multiple cycles plus a time equivalent to twice the standard deviation.

[0037] The recommended stabilization time calculation unit 26 displays a bar graph of the stabilization times for multiple cycles on the touch panel display 30t of the interface 30. The recommended stabilization time calculation unit 26 also displays the recommended stabilization times on the bar graph on the touch panel display 30t. This allows the interface 30 to select the recommended stabilization time via the touch panel display 30t. The recommended stabilization time calculation unit 26 and the interface 30 constitute a selection unit.

[0038] Next, refer to Figure 3 An example of processing in the case where the control unit 20 selectably displays the recommended stabilization time on the touch-panel display 30t will be described in detail with reference to the flowchart of FIG.

[0039] First, for example, one of a plurality of weighing hoppers 6 is selected as the weighing hopper 6 to be measured in real time (step S1). Real-time measurement is performed on the selected weighing hopper 6, and time-series measurement values ​​are acquired (step S2). The time measurement unit 24 measures the stabilization time of the acquired time-series measurement values, and the measured stabilization time is stored in the storage unit 22 (step S3).

[0040] A determination is made as to whether the accumulated number of stabilization times in the storage unit 22 is greater than or equal to a certain value (step S4). If the answer is "No" in step S4, the process returns to step S1. If the answer is "Yes" in step S4, the recommended stabilization time calculation unit 26 calculates the average and standard deviation of the stabilization times (step S5). The recommended stabilization time calculation unit 26 calculates the recommended stabilization time. Furthermore, a bar graph of the stabilization time and the recommended stabilization time are displayed on the touch panel display 30t (step S7).

[0041] Figure 4 This is a graph showing an example of the stabilization time S0. Figure 4 In the example, an example of a time series measurement value K is shown that is measured in real time. In the time series measurement value K, after rapidly increasing and reaching a peak value according to the supply of the article M to the measuring hopper 6 (the moment t0 when the gate 5a of the pool hopper 5 changes from a closed state to an open state), the amplitude of the change decreases while changing in a wave-like manner and converges to a certain convergence value. The moment of opening the gate 5a can be obtained based on the drive signal for the gate 5a. On the time series measurement value K, a stable region R0 of a certain width is set based on the convergence value. The time series measurement value K converges to the amplitude of the change that is considered to be within the stable region R0. In such a time series measurement value K, the waveform is traced in a retroactive time manner (from right to left in the figure), so as to determine the moment t1 when the value enters the stable region R0. As a result, the period from moment t0 to moment t1 is obtained as the stable time RT.

[0042] Figure 5 30t is a diagram showing a display example of the touch panel display 30t. Figure 5 In the example, a bar graph is shown with frequency on the vertical axis and stabilization time on the horizontal axis. The recommended stabilization time is also displayed on the bar graph. By displaying the accumulated statistical data of the stabilization time RT in the form of a bar graph, it is possible to show the criteria for adjusting the stabilization time RT. Furthermore, an appropriate stabilization time value is presented as the recommended stabilization time. For example, on such a touch-panel display 30t, the user can select the recommended stabilization time value by touching it or by entering the value displayed on another screen.

[0043] As described above, the combination weighing device 1 can obtain the stabilization time RT, which varies each time an article M is added to the weighing hopper 6, over multiple cycles. Based on the standard deviation obtained from the statistical data of the obtained stabilization time RT, a recommended stabilization time that can maintain a predetermined weighing accuracy can be selected. This allows for setting an appropriate stabilization time RT without relying on experience or intuition.

[0044] In the combined metering device 1, the time measurement unit 24 determines the convergence value of the time series measurement value K stored in the storage unit 22 over multiple cycles. It then determines a region of a certain width based on the convergence value of each cycle as the stable region R0. This allows the stable region R0 to be specifically determined. Alternatively, the stable region R0 may be a fixed value set by, for example, a remote controller.

[0045] In the combined metering device 1, the time measurement unit 24 tracks the time-series measurement values ​​K stored in the storage unit 22 in a retroactive manner to determine the time when the time-series measurement values ​​K entered the stable region R0. This allows the specific determination of the time when the time-series measurement values ​​K entered the stable region R0.

[0046] In the combination metering device 1, the interface 30 includes a touch panel display 30t that displays a bar graph of the stabilization time RT of a plurality of cycles and also displays the recommended stabilization time on the bar graph.

[0047] In the combination metering device 1, the recommended stabilization time is the time obtained by adding a time equivalent to twice the standard deviation to the average value of the stabilization time RT obtained in a plurality of cycles. In this case, an appropriate stabilization time RT can be specifically set.

[0048] In the combination metering device 1, the time t0 at which the article M is supplied to the metering hopper 6 (corresponding to the supply of the article M to the metering hopper 6) is correlated with the time t0 at which the gate 5a of the pool hopper 5, which supplies the article M to the metering hopper 6, is opened. In this case, the time t0 at which the gate 5a of the pool hopper 5 is opened can be used as the starting point of the stabilization time RT.

[0049] In the combined metering device 1, the time until the metering value converges into the stable region R0 is measured starting from the moment when the metering value becomes unstable. For example, when the gate 62 of the metering hopper 6 is closed to receive the article M, or the gate 5a of the pool hopper 5 is opened to supply the article M to the metering hopper 6, the metering value becomes unstable, so it is preferable to start measuring from that moment. This is because these moments can be obtained by the output moment of the drive signal that opens and closes the gates 62 and 5a. However, the moment to start timing is not limited to this. For example, when a discharge request signal is received from an external device such as a packaging machine, and the article M is supplied to the metering hopper 6 a certain time after that point in time, the timing can also be started from the time when the discharge request signal is received, and the above-mentioned certain time is subtracted from the measured time at that time, thereby calculating the stabilization time until the unstable metering value stabilizes.

[0050] As mentioned above, although one embodiment of the present invention has been described, one embodiment of the present invention is not limited to the above-mentioned embodiment.

[0051] In the above embodiment, multiple pool hoppers 5 and metering hoppers 6 are arranged in a ring, but this is not limited to this and may also be arranged in a matrix. The above embodiment and the above modification may also include multiple auxiliary hoppers. In the above embodiment and the above modification, some of the functions of the control unit 20 may be performed by another control unit or by a server capable of communicating with the combination metering device 1.

[0052] In the above-described embodiment and variations, the recommended stabilization time may be automatically selected as the stabilization time RT when the recommended stabilization time is calculated. In the above-described embodiment and variations, the stabilization time RT for each item M may be collected to select a recommended stabilization time appropriate for the item M. In the above-described embodiment and variations, the stabilization time RT may be collected in association with actual operating conditions (operation rate and defect rate) to select a more optimal recommended stabilization time.

[0053] According to one aspect of the present invention, a combination metering device can be provided that can set an appropriate stabilization time without relying on experience or intuition.

Claims

1. A combination weighing device that repeatedly performs the following cycle: feeding articles to a plurality of weighing hoppers for weighing, determining a combination of the plurality of weighing hoppers based on the plurality of weighing values ​​obtained, selecting a combination close to a target weight value from the determined combinations, and discharging the articles from the plurality of weighing hoppers associated with the selected combination; The combined metering device comprises: a storage unit for storing time-series measurement values ​​successively acquired by the measuring hopper; a time measuring unit that measures an elapsed time as a stabilization time until the measured values ​​stabilize, the elapsed time being the time elapsed from the time corresponding to the supply of the article to the weighing hopper to the time when the measured values ​​of the time series stored in the storage unit converge into a region that is considered stable; and The selection unit includes a recommended stabilization time calculation unit, which is capable of obtaining the stabilization time through the time measurement unit in multiple cycles, storing and accumulating the stabilization time as statistical data in the storage unit, and calculating a recommended stabilization time based on a standard deviation of the multiple stabilization times when the stabilization time of the stored multiple cycles is greater than a specified number. The recommended stabilization time refers to the stabilization time that can maintain a specified measurement accuracy.

2. The combined metering device according to claim 1, wherein: The time measurement unit obtains convergence values ​​of the time-series measurement values ​​stored in the storage unit over the plurality of cycles, and obtains a region of a certain width based on the obtained convergence value of each cycle as the region considered stable.

3. The combined metering device according to claim 1 or 2, wherein: The time measurement unit traces the time-series measurement values ​​stored in the storage unit in a retroactive manner to identify the time when the time-series measurement values ​​enter the region considered to be stable.

4. The combined metering device according to claim 1 or 2, wherein: The selection unit includes a display unit that displays a bar graph of the stabilization time of a plurality of the cycles and also displays the recommended stabilization time on the bar graph.

5. The combined metering device according to claim 1 or 2, wherein: The recommended stabilization time is a time obtained by adding a time equivalent to twice the standard deviation to an average of the stabilization times obtained in a plurality of the cycles.

6. The combined metering device according to claim 1 or 2, wherein: The timing corresponding to supplying the article to the weighing hopper is related to at least any one of closing the article discharge gate in the weighing hopper, opening the article discharge gate in the weighing hopper, and opening the article discharge gate in the supply hopper that supplies the article to the weighing hopper.

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