JP3633668B2 - Operation method of powder packaging machine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for operating a powder packaging machine.
[0002]
[Prior art]
Conventionally, screw blowing type powder bagging machines have been used to wrap wheat flour, cement and the like in craft bags and the like. In this filling machine, a valve provided in a kraft bag is opened by a nozzle by opening a valve provided in a kraft bag, and the inside of the nozzle is pushed in and combined with air to be packed. This type of filling machine used for powdered foods mainly composed of wheat flour and flour often changes its performance extremely when the type of powder to be filled changes. It looks like a wet powder, making it difficult to fill or it takes a very long filling time.
[0003]
In order to fill such a powder into a kraft bag, it is not possible to fill the kraft bag simply by increasing the amount of air, but rather, a filling method in which the amount of air is reduced and the screw is mainly pushed in is often desirable. In addition, even in the case of a powder that is easy to handle, such as wheat flour, the non-use of air is preferable because the dust generation phenomenon is reduced. The present inventor has developed and applied for a patent for various devices that can be filled accurately and while maintaining capacity in a powder packaging machine using a small amount of air (Japanese Patent Application Nos. 58-225278 and 62-62). 196886). The development of such a powder packaging machine was mainly related to its structure. In addition, regarding a method for supplying powder to the weighing device, a method has been developed in which the amount of supply at the time of small input in the second stage is continuously reduced to maintain high accuracy and high capacity (Japanese Patent Application No. 7-98554). ).
[0004]
[Problems to be solved by the invention]
On the other hand, when placed in a mix plant that uses wheat flour as the main raw material, a variety of powders can be used in a single packaging machine or system, ranging from products containing a large amount of fats and oils to easy-to-handle powders similar to flour. In each packaging line, they are switched according to brands. In such a case, it is necessary to have good performance per unit time and good weighing accuracy, but it is also necessary to make adjustments as soon as possible at the time of product switching and shorten the switching time. .
[0005]
This switching operation is to flow several bags of target products and package them as switching products, and adjust the measurement value and the filling speed during this period, and the products in the meantime often become defective products. From this point of view, it is necessary to perform the switching adjustment work with as few products as possible. Specifically, this operation is based on the adjustment value of the previous operation, and the adjustment of the weighing and filling speed and the time distribution of large and small dispensing are performed manually. It is required to be able to automatically start up during this switching operation.
[0006]
Moreover, in the operation of such a powder packaging machine, the load fluctuates due to changes in the powder temperature, etc., depending on the type of powder raw material to be packaged. Therefore, it is common to operate at a low load in order to operate stably. For such a raw material, a control method is desired that can be operated with a sufficient load at all times and can be operated with an increased filling capacity.
[0007]
The present invention has been made in view of the above points, and in a powder packaging machine equipped with a supply screw feeder and a filling screw, when the load fluctuates due to changing the type of powder to be packed, etc. An object of the present invention is to provide a method for operating a powder packaging machine that can quickly adjust the operating conditions of the powder packaging machine, always operate with sufficient load, and improve the filling capacity.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention feeds powder from a supply screw feeder to a filling screw, fills the bag with the filling screw, automatically measures the amount of the filled powder, and the measured value is In a filling type powder packaging machine that automatically drops filled bags when the set value is reached, so that the load current of the filling screw falls within a predetermined range of rated current values. After supplying a constant amount by controlling the rotation speed of the supply screw feeder, the rotation speed is adjusted so that the load current is maintained slightly higher than 0 when the filling speed of the filling screw in the second stage is continuously reduced. It is characterized by reducing.
[0009]
Further, the present invention is characterized in that it is performed while adjusting the supply amount in the second stage so that the load current value of the filling screw at the time of stepless deceleration is maintained larger than zero (0).
[0010]
Further, the present invention is characterized in that the adjustment is repeated for each bag.
[0011]
【Example】
The present invention will be described below with reference to the drawings.
[0012]
FIG. 1 is a diagram illustrating a schematic configuration of a powder packaging machine.
[0013]
The powder packaging machine 11 feeds the powder stored in the storage tank 12 to the filling screw 16 through the communication port 15 by the supply screw feeder 14 and further receives the filling bag (not shown) received by the nozzle 1 through the reducer 17. )). The filling bag is filled with powder from the nozzle 1 while receiving a load at the bag receiving base 25. The load of the bag cradle 25 is transmitted to the load cell 26a by a bag to read the weight.
[0014]
When the powder of a constant weight is supplied and reaches a predetermined value, for example, 25 kg, the bag cradle 25 rotates due to the movement of the center of gravity and falls off the nozzle 1 and falls. These operating cycles are started automatically by inserting a blank bag into the nozzle 1 and by a switch set in this part. The screw feeder 14 is driven by a variable motor. In this embodiment, the rotational speed is changed by adjusting the voltage of the DC motor. The filling screw 16 rotates simultaneously with the screw feeder 14. Shifting is performed by adjusting the servo motor voltage. The stirrer 13 agitates the powder in the storage tank 12 and assists its discharging action.
[0015]
The conventional powder packaging machine 11 uses the hollow rotating shaft of the filling screw 16 to blow high-pressure air from the hollow portion toward the tip of the filling screw 16 for auxiliary filling or main filling of the powder. However, air assistance may not be used in the present invention.
[0016]
Adjustment at the time of product switching in the powder packaging machine 11 was performed as follows.
[0017]
The rotation speed of the filling screw 16 is adjusted by changing the charging speed in two stages of large charging and small charging. First, large charging is performed with large capacity, and small charging is performed on the way with small capacity. The weight at the time of switching between large input and small input is determined for each brand. The screw feeder 14 adjusts the rotational speed so that the load current of the filling screw 16 is within the rating.
[0018]
In this conventional adjustment method, the above parameters are set once and packaged, and the weight is weighed bag by bag. As a result, the load current of the motor of the filling screw 16 is confirmed, and if it is less than the rated current, it is left as it is. If it is too small, the rotation speed of the screw feeder 14 is increased so as to increase the large input current. However, even if it is adjusted in this way, it can be operated as it is during normal operation, but if the state of the powder changes, the load current of the filling screw 16 may increase and exceed the rating. In this case, a failure may occur.
[0019]
For this reason, the load is reduced so that the load of the filling screw 16 can be accommodated to some extent, that is, the screw feeder 14 is often set and operated at a low rotation speed, resulting in the capability. You are driving with a drop. Therefore, the filling capacity is increased by performing control that can sufficiently and automatically cope with the load fluctuation.
[0020]
FIG. 2 is a block diagram of an apparatus for carrying out the method for operating the powder packaging machine according to the present invention.
[0021]
The screw feeder 14 and the filling screw 16 are driven by DC motors 14a and 16a, respectively. The load currents of the DC motors 14a and 16a are measured by the current measuring device 31, respectively. These DC motors 14a and 16a are provided with control voltage increase / decrease devices 30 and 34, respectively, in order to increase or decrease the rotational speed by increasing or decreasing the voltage. There is a weighing unit 24 for measuring the weight of the bag-packed powder filled by the filling screw 16, and when the bag is filled with the powder, its weight is weighed. Both the weight signal from the weighing unit 24 and the current signal from the current measuring device are sent to the setting calculation device 35. Only the current value 14 a is sent from the current measuring device 31 to the comparator 33. Weighing and brands to be packed are input from the set value input device. These values are sent to the arithmetic unit 35 and become control signals, while parameters are set based on these values. Among the set values, the upper and lower limit values of the control width for the initial value 14a are sent to the comparator 33. When the empty bag is loaded, the operation is automatically performed by the first control voltage based on the set values of the DC motors 14a and 16a. The step width control 32 is performed by the difference between the current value of 14a and the set value, and an increase / decrease command is sent to the control voltage increase / decrease device 30. Here, the voltage of 14a is changed to change the rotation speed. On the other hand, the voltage 16a is commanded from the arithmetic unit 35 to the increase / decrease device 34 so that the rotational speed changes steplessly by the weight of the weighing unit 24 and the set value.
[0022]
FIG. 3 is a flowchart of a method for operating a powder packaging machine according to the present invention.
[0023]
The automatic operation method of the powder packaging machine according to the present invention is a two-stage control method, that is, a two-stage filling method consisting of a large input and a small input, and the second stage is not a quantitative supply method, and the powder is supplied steplessly. This is a stepless control system that reduces the supply.
The automatic driving method of the present invention will be described in detail with reference to FIG.
(1) Set the same brand large lead-out time that has been set in advance or set each parameter to the previous adjustment value, the rotation speed (control voltage) of the supply screw feeder 14 at the large stick-out, and the large stick-out amount . (F-1)
(2) Operate under these set conditions and wrap one bag at the same time as the start. During this measurement, the maximum load current value during the supply time of the filling screw 16 is measured, and the load current during the small supply time (at this time during the stepless deceleration operation) is measured by switching . The first bag is the set value or the previous adjustment value and is not adjusted. (F-2)
(3) In filling the second bag , the maximum load current value of the filling screw 16 is observed, and if it is lower than the predetermined lower limit value, the control voltage of the supply screw feeder 14 is increased with the minimum step width ( supply screw). As a result , the control voltage of the supply screw feeder 14 is increased until the load current value of the filling screw 16 becomes larger than the lower limit value. If the maximum load current value of the charging screw 16 at this time needs to include within this range is above than the upper limit, lowering the control voltage value of the supply screw feeder 14 to this range. At this stage, the supply screw feeder 14 is controlled so that the load current of the filling screw 16 becomes maximum. (F-3) (F-4) (F-5)
(4) When the filling amount set by the first set value is reached and filling is performed by the second stepless control, the load current of the filling screw 16 is measured and filled. If the load current is positive at this time, the amount of stepless control is reduced under the next bag filling condition. To fill in the state of it. (F-6) (F-7)
(5) The load current value of the filling screw 16 is measured under the filling condition in the next bag, that is, in the state where the filling weight in the second stage (stepless control) is smaller than the previous bag, and still on the positive side If so, the amount of stepless control in the next bag is reduced and this adjustment is repeated. (F-8) (F-9) (F-10)
(6) When the amount of charge in the second stage is reduced and the load current value of the filling screw 16 becomes negative, the amount of charge in the second stage is increased again and the adjustment is finished when the load current becomes positive. To do. (F-11)
(7) If the load current shows a minus side in the stepless control of (4) in the initial setting , the filling weight in the stepless control is increased for packaging. Repeat this further. When the load current of the filling screw 16 becomes positive , the adjustment is finished. (F-12) (F-13) (F-14)
[0024]
In this second-stage continuously decreasing supply system, the rotational speed of the filling screw 16 is decreased in order to reduce the supply speed. However, if the deceleration is too fast, the brake will be in a brake state and the filling screw 16 will become clogged. Causes to stop. At this time, it is necessary to reduce the deceleration, and the reverse current generated in the motor is used as the index. In other words, when reverse current occurs, the deceleration of the second stage input is too fast, so it is determined that the reverse current has occurred in the motor due to inertial force, and it is necessary to adjust the second stage input speed. ing.
[0025]
In this second-stage stepless control, if the deceleration is large, the small input time is shortened. However, if the deceleration is too large, the brake state is established. However, the brake state is eliminated by reducing the deceleration. However, reducing the deceleration increases the time for stepless input, and therefore increases the amount of small input. In order to increase the small input amount, the switching time from the large input to the small input is increased. If no reverse current is generated, the deceleration is increased so that a small amount of reverse current is generated, that is, the amount of small inputs is increased.
[0026]
【The invention's effect】
As described above, the operation method of the powder packaging machine according to the present invention is that the powder is fed from the supply screw feeder to the filling screw, filled into the bag by the filling screw, and the amount of the filled powder is automatically set. In the powder packaging machine of the filling method in which the filled bag is automatically dropped when the measured value reaches the set value, the load current of the filling screw is set within a predetermined range. After supplying a constant amount by controlling the rotation speed of the supply screw feeder so that it falls within the rated current value, the load current is slightly increased when continuously reducing the filling speed of the filling screw in the second stage. Since it is configured to reduce the rotation speed so as to maintain, the following excellent effects can be obtained.
(1) The overall charging time was shortened and the charging accuracy was improved.
(2) Switching at the time of product switching has become faster and switching time has been shortened.
(3) The motor load at the time of large input is sufficiently applied, and the overall capacity is improved.
(4) The product switching operation in the filling adjustment operation of the powder packaging machine can be fully automated.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of a powder bagging machine.
FIG. 2 is a block diagram of an apparatus for carrying out a method for operating a powder packaging machine according to the present invention.
FIG. 3 is a flowchart of a method for operating a powder packaging machine according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Powder bagging machine 12 Storage tank 13 Stirrer 14 Screw feeder 14a DC motor 16 Filling screw 16a DC motor 17 Reducer 24 Weighing part 25 Bag receptacle 26 Control apparatus 26a Load cell 30 Control voltage increase / decrease apparatus 31 Load current value 32 Step width control 33 45 Upper / Lower Limit Comparator 34 Control Voltage Increase / Decrease Device 35 Setting Calculation Device 36 Weighing Measurement 37 Setting Value Input

Claims (3)

The powder is fed from the supply screw feeder to the filling screw, filled into the bag by the filling screw, the amount of the filled powder is automatically measured, and when the measured value reaches the set value, the filled bag In a powder packaging machine of a filling method that automatically drops the bag , the bag is filled in two stages, a first stage of large input and a second stage of small input,
In the first stage, the rotation speed of the supply screw feeder is controlled so that the load current of the charging screw falls within a preset rated current value within a predetermined range, so that the charging screw is rotated at a constant amount. Make the supply
In the second stage, the rotation speed of the filling screw is steplessly reduced and supplied to a set value, and the stepless reduction is performed so that the load current of the filling screw is maintained at 0 or a plus side. A method of operating a powder packaging machine, wherein the number of rotations of the screw is reduced. 2. The operation of the powder packaging machine according to claim 1 , wherein the adjustment method for maintaining the load current of the filling screw at 0 or on the plus side is performed by increasing or decreasing the supply amount in the second stage. Method. The method of operating a powder packaging machine according to claim 1 or 2, wherein the adjustment of the supply amount in the second stage is repeatedly performed for each bag.

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