JP4682755B2 - Pulper control device - Google Patents

Description

  The present invention relates to a pulper control device for papermaking that disperses raw pulp into water to produce a paper stock having an optimum concentration, and in particular, a pulper that controls the paper stock concentration by controlling the rotational speed of a circulator. The present invention relates to a control device.

A conventional pulper control device will be described with reference to FIG.
The pulper 1 shown in FIG. 3 includes a circulator 1 </ b> A for stirring the liquid and a level meter 13. The raw material 19 is carried by the conveyor 2, and white water is poured from the white water pipe 9. The paper stock obtained by disaggregating the raw material 19 by stirring is discharged from the discharge pipe 15 to the next process (see Patent Document 1).
The input amount of the raw material 19 is controlled by a conveyor input amount control system, the amount of white water injected is controlled by a flow rate control system, the level of the liquid in the pulper 1 is controlled by a level control system, and the discharge pipe The density of the stock discharged from 15 is controlled by a density control system. On the other hand, the circulator 1A is ON / OFF controlled by a pulser motor 1B. The entire electrical components of these control systems constitute a pulper control device.
The conveyor input amount control system includes a weight detector 5 that detects the total weight of the tare, such as the raw material 19 and the conveyor 2, a conveyor motor 3 that drives the conveyor 2, and a conveyor activation that opens and closes the power supply of the conveyor motor 3. In response to the switch 4, the conveyor input command signal Q _s , the weight detector 5 signal W _f , and the conveyor constant setting device 23, the input amount of the raw material 19 to be input to the pulper 1 is set by the conveyor constant setting device 23. The conveyor input amount controller 6 controls the opening and closing of the conveyor start switch 4 so as to have a predetermined value.
The flow rate control system works with the valve 10 and the flow meter 11 provided in the white water pipe 9 and the flow rate of the white water to be input to the pulper 1 in response to the signal q _f of the flow meter 11 to be equal to the flow rate command q _s. It is comprised from the flow rate controller 12 which controls the opening degree.
The level control system is provided in the pulper 1 to measure the water level in the pulper 1, and receives the signal L _f to keep the water level in the pulper 1 at a predetermined value, and the flow rate command q of the flow control system. _The level controller 14 outputs _s and the flow rate control system described above.
The density control system is provided in the discharge pipe 15 to detect the density ρ of the paper, and the density of the paper discharged from the discharge pipe 15 in response to the density command ρ _s and the signal ρ _f of the density meter 17. Is configured to be close to the concentration command ρ _s and output a conveyor input command signal Q _s , and the conveyor input control system described above.
The rotation of the circulator 1A is controlled by turning on and off the switch 20 to start and stop the electric motor 1B for the pulper, and the stirring of the pulper 1 is controlled.

The pulper control device configured as described above operates as follows.
First, the level of the pulper 1 is controlled as follows. The level of the pulper 1 is detected by the level meter 13 when the next process requires a predetermined amount of paper and the paper in the discharge pipe 15 having a predetermined concentration is discharged at a predetermined flow rate by the pump 16 or the like. Then, the level controller 14 works, and if it is lower than the predetermined level, the flow rate command signal q _s is increased to increase the flow rate of white water, and if it is higher, the signal q _s is decreased to decrease the flow rate of white water and the level of the pulper 1 is increased. It is maintained at a predetermined value. At this time, the flow rate adjusting meter 12 enters the flow command q _s level adjusting meter 14, as compared to the flow meter 11 of the signal q _f for detecting the flow rate of the white water of white water pipe 9, the direction of the signal q _f small flow rate if is less increased flow rate by opening the valve 10, the more greatly the flow direction of the signal q _f reduce flow by closing the valve 10, the signal q _f is controlled to be equal to the flow rate instruction q _s.
When the level controller 14 inputs the signal L _f of the level meter 13, it is compared with the internally set level command L _s . If the signal L _f is smaller than the level command L _{s and} the level of the pulper 1 is low, the flow rate command q _s is increased to increase the amount of white water injected, and if the signal L _f is greater than the level command L _{s and} the level of the pulper 1 is high, the flow rate command q _s is decreased to reduce the amount of white water injected, and the signal L _f is a level command Control to be equal to L _s .
The stock concentration is then controlled as follows. When the density of the stock is detected by the densitometer 17 and the density signal ρ _s is input, the density controller 18 increases the conveyor input amount command Q _s if the density signal ρ _f is smaller than the density command ρ _s , and the density command ρ If the density signal ρ _f is larger than _{s, the} conveyor input amount command Q _s is decreased. That is, the density controller 18 increases the conveyor input amount command Q _s if the density of the stock is lower than the concentration set by the concentration setting unit 8, and decreases the conveyor input amount command Q _s if it is dark.
When the conveyor controller 6 inputs the conveyor input amount Q _s , the raw material 19 is determined from the total weight W _f of the tare and the raw material such as the conveyor 2 detected by the weight detector 5 and the conveyor constant set by the conveyor constant setting unit 23. to determine the excess and deficiency of input amount in search of actual input amount Q _f of. The constants of the conveyor set by the conveyor constant setting unit 23 are the conveying speed of the conveyor, the weight per raw material 19, the interval between the raw materials 19, the length of the conveyor, and the like. The input amount of the raw material 19 per unit time is determined. Based on the determination of excess and deficiency and the conveyor constant set by the conveyor constant setting unit 23, the frequency of opening and closing the conveyor start switch 4 is obtained and commanded, and the drive of the conveyor motor 3 is controlled to make a bulk material. input of 19 is controlled to be equal to the amount set by the conveyor input amount command Q _s.
In this manner, the paper material concentration required for the next step is discharged through the discharge pipe 15 and the paper material concentration is maintained at a predetermined value while keeping the level of the pulper 1 constant.
JP-A-7-145580

However, in the conventional pulser control device, the motor for the pulser performs on / off control according to the output of the concentration controller, and the circulator is intermittently rotated at a constant speed, so the disaggregation time until a predetermined concentration is obtained is accurately controlled. It is not easy to do, and the concentration after disaggregation is also unstable. In recent years, the output of the electric motor for the pulser has increased in proportion to the increase in the capacity of the pulser. It is necessary to adopt a starting method that limits a voltage drop due to a starting current such as reactor starting.
However, these start-up methods not only limit the current at start-up, but also result in limiting the torque at start-up. A large torque is required to disaggregate raw materials that have not been disaggregated as a characteristic of the pulper at the start-up, and if the start-up torque is insufficient, not only can disaggregation occur, but the possibility of starting failure and shortening the life of the motor increases. Yes. Further, since the circulator is operated at a constant speed and the rotational speed cannot be changed, there is a problem that the mechanical loss is large by always rotating at a high rotational speed.
In addition, the densitometer is attached in the middle of the discharge pipe, and as time passes, it becomes difficult to accurately measure the concentration because the paper material adheres, and labor such as disassembly and cleaning is required.
The present invention has been made in view of such problems, and ensures a necessary torque at the time of start-up, eliminates a voltage drop due to a start-up current at the time of start-up, reduces a mechanical loss of the pulper, and causes a start-up failure. The purpose is to prevent incurring, extend the life of the motor, stabilize the concentration after disaggregation, and eliminate the need for labor such as disassembly and cleaning. It is still another object of the present invention to provide a pulper control device that can obtain a stock having a constant concentration without a densitometer.

In order to solve the above problem, the present invention is configured as follows.
In the first aspect of the present invention, the bulk material and white water are put into a pulper and stirred by a circulator,
The flow rate is controlled to control the water level of the pulper, and the concentration of the paper discharged from the pulper
In the pulper control device that controls so that the value becomes a predetermined value, the density for detecting the density of the paper stock
And a second density controller for controlling the density of the paper by comparing the density command and the signal of the density meter
And a speed control device that controls the rotational speed of the flow circulator in response to a command from the second concentration controller.
It is characterized by having.
The second aspect of the present invention controls the density of the paper by comparing the density command and the signal of the densitometer.
And the operation of the conveyor is controlled according to the input amount output by the concentration controller.
And a conveyor controller that feeds raw materials into the pulper.
3rd this invention is for the conveyor which conveys the said raw material, and the conveyor which drives the conveyor
An electric motor, and a conveyor start switch for opening and closing between the electric motor for the conveyor and a power source;
A conveyor and a weight detector for detecting the weight of the raw material, the conveyor controller
The actual input amount obtained from the weight detector signal and the conveyor constant determined by the conveyor setter is
Control the opening and closing of the conveyor start switch by calculating to be equal to the input amount command
It is characterized by controlling the drive of the conveyor.
According to a fourth aspect of the present invention, when the speed control device receives a speed command, the circulator receives the speed command.
A speed controller that works to rotate at a corresponding speed and outputs a frequency command, and the frequency command
And a pulser driving device that drives a motor connected to the circulating device at that frequency when received
It is characterized by becoming.
According to a fifth aspect of the present invention, there is provided a torque set value and a speed control device for setting the driving torque of the circulating device.
Torque controller for giving a speed command to the speed control device based on the detected torque of the circulator
It is characterized by having.
According to a sixth aspect of the present invention, when a difference between the torque setting value and the detected torque is equal to or less than a predetermined value, the predetermined value is determined.
A torque discriminator that outputs a speed command of the motor, an output of the torque discriminator and an output of the torque controller.
A minimum value discrimination circuit that outputs the smaller one of the forces is provided.
According to a seventh aspect of the present invention, when the speed control device receives a speed command, the circulator receives the speed command.
Speed controller that works to rotate at a speed according to the output and outputs a frequency command, and its frequency command
And a pulser driving device that drives a motor connected to the circulating device at that frequency.
It is characterized by

According to the first aspect of the invention, the second concentration controller controls the concentration based on the signal from the densitometer, and receives the command to control the rotational speed of the circulator, so that the concentration of the paper stock can be stabilized. effective.
According to the second invention, the density is controlled by the density controller, and the conveyor operation is controlled by the conveyor controller. Therefore, there is an effect that the life of the motor can be extended and the density of the paper stock can be stabilized.
According to the third invention, since the opening and closing of the conveyor start switch is controlled to control the driving of the conveyor, there is an effect that the density of the paper stock can be stabilized.
According to the fourth invention, since the speed control device is composed of the speed controller and the pulser drive device, the start torque is secured to prevent the start failure, the voltage drop is limited, and the life of the motor is extended. There is an effect that the density of the stock can be stabilized.
According to the fifth invention, since the torque controller performs torque control and gives a speed command to the speed control device, the density control is performed without a densitometer, the mechanical loss is reduced, the density of the paper stock is stabilized, There is an effect that labor for cleaning can be eliminated.
According to the sixth invention, if the difference between the torque setting value and the detected torque is less than or equal to a predetermined value, any of a torque determiner that outputs a predetermined speed command, an output of the torque determiner, and an output of the torque controller Since the minimum value discriminating circuit that outputs the smaller one is provided, the mechanical loss can be reduced.
According to the seventh invention, since the speed control device is composed of the speed controller and the pulser drive device, the start torque is secured to prevent the start failure, the voltage drop is limited, and the life of the motor is extended. There is an effect that the density of the stock can be stabilized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a pulper control device according to the present invention. What differs from FIG. 3 is that a second concentration controller 18A, a pulper driving device 21, and a speed controller 22 are provided. Since the same operations as those in FIG. 3 perform the same operations, only differences from FIG. 3 will be described.
A speed control system is configured by the motor 1B for pulper, the speed controller 22 and the pulser driving device 21 which are not shown in FIG. 3, and the speed control device is constituted by the pulser driving device 21 and the speed controller 22. The concentration controller 8, the concentration meter 17, the second concentration controller 18 </ b> A, and the speed control system constitute a second concentration control system.
The speed controller 22 inputs a rotational speed signal (not shown) of the speed command v _s and pulper electric motor 1B, pulper drive working so that the rotational speed of the pulper electric motor 1B matches the rotation speed corresponding to the speed command v _s The frequency command is output to 21. For example, an inverter is used for the pulser driving device 21, and when a frequency command is input, a rotating magnetic field corresponding to the frequency is generated in the stator of the pulser motor 1B to rotate the rotor of the pulser motor 1B. Such pulper electric motor 1B in the rotational speed of the whirling machine 1A is rotated at a rotational speed corresponding to the speed command v _s is controlled.
The second concentration controller 18A inputs the concentration command ρ _s of the concentration setting device 8 and the concentration signal ρ _f of the concentration meter 17 which are the same as those of the concentration controller 18, and works so as to reduce the difference between them and the speed command v _s . Output.
The second concentration controller 18A and the concentration controller 18 receiving the same signals ρ _s and ρ _f have different time constants, that is, responsiveness. The same density control system as in FIG. 3 that inputs the density signal ρ _f of the densitometer 17 and controls the input amount of the conveyor to control the density of the paper stock, even if the conveyor 2 is driven continuously, the raw material 19 is intermittent Therefore, the fluctuation range of the concentration becomes large and the responsiveness cannot be increased, the time constant is large, and the responsiveness is set low. On the other hand, the second concentration control system has a smaller time constant and higher response than the concentration control system in FIG. Even if the density fluctuation of the stock increases, the mixing speed of the white water and the raw material is quickly controlled by controlling the rotation speed of the flow circulator 1A, so that the density of the stock can be kept constant.
Further, when the pulper 1 dormant activates the circumfluence device 1A starts the operation, the second density controllers 18A gradually increases the speed command v _s. Accordingly, the speed controller 22 also gradually increases the frequency command and the pulser motor 1B gradually increases the rotational speed, so that the starting current can be suppressed and a large current such as direct start does not flow. No voltage drop occurs at startup. Therefore, a large-capacity pulper driving device is not required, and the mechanical loss of the pulper can be suppressed.

FIG. 2 is a diagram showing the configuration of the pulper control device of the second embodiment. 1 is different from FIG. 1 in that a torque controller 24, a torque determiner 25, and a minimum value discriminating circuit 26 are provided in place of the two concentration controllers 18A and 18, and the signal of the densitometer 17 is not fed back and the conveyor The command is not output to the controller 6. The densitometer 17 shown in the figure is used only for monitoring the concentration.
The speed control system is configured by the motor 1B for the pulper, the speed controller 22, and the pulser driving device 21, and the speed control device is configured by the pulser driving device 21 and the speed controller 22. Further, a torque controller 24 which outputs a speed signal v _TR by entering the torque difference ΔT of the difference between the detected torque T _f of the torque set value T _s and pulper driving device 21 outputs, pulper driving device 21, the speed controller 22 constitutes a torque control system.
Working as the rotational speed of the speed controller 22 the speed command v _s and by entering the speed signal (not shown) of the electric motor 1B for pulper pulper electric motor 1B matches the rotation speed corresponding to the speed command v _s pulper drive 21 The frequency command is output to. For example, an inverter is used for the pulser driving device 21. When a frequency command is input, a rotating magnetic field corresponding to the frequency is generated in the stator of the pulser motor 1B, and the rotor of the pulser motor 1B rotates at the frequency. Rotate by number. Thus the pulper electric motor 1B at a rotational speed corresponding to the speed command v _s rotates, the rotation speed of the swirling flow device 1A is controlled.
The torque determiner 25 receives the torque difference ΔT and the disaggregation completion torque difference set value ΔT _s . If the torque difference ΔT is smaller than the disaggregation completion torque difference set value ΔT _s , it is determined that disaggregation is completed and the signal v _min is received. Output. The value of v _min at this time is the minimum speed at which the disaggregated raw material does not precipitate. When the minimum value judgment circuit 26 inputs a velocity signal _{v TR} and the signal _{v min,} and outputs the better one small speed controller 22 as a speed command _{v s.}
When the torque difference ΔT is larger than the disaggregation completion torque difference set value ΔT _s , the torque discriminator 25 changes v _min to the value of the maximum speed of the motor 1B, assuming that disaggregation is not completed. It velocity signal v _TR minimum determination circuit 26 in the torque controller 24 is given priority by. Accordingly, the torque controller 24 works so that the torque of the motor 1B becomes equal to the torque set value T _s, and sets the speed command v _s of the speed controller 22, and the rotational speed of the motor 1B is controlled by the speed set value. The Thus circumfluence device 1A is disaggregation until the torque difference [Delta] T is smaller than the macerating completion torque difference setting value [Delta] T _s ultimately continues macerated until a predetermined raw material concentration is continued.
Since it is in this way, rotation of the circulating machine 1A can be stabilized, and the circulating machine 1A can be rotated at the number of rotations at which electric power is minimized.
Incidentally, when starting the circumfluence machine 1A it is stopped, gradually increases the speed command value v _s output by the torque controller 24. Accordingly, the speed controller 22 also gradually increases the frequency command and the pulser motor 1B gradually increases the rotational speed, so that the starting current can be suppressed and a large current such as a direct-on start does not flow. No voltage drop occurs at startup. Therefore, a large-capacity pulper driving device is not required, and mechanical loss of the pulper can be suppressed.

  The present invention can be applied not only to a circulator for separating materials such as papermaking machines but also to an agitator for a tank that stores the separated materials.

Configuration diagram of the pulper control device of the present invention Configuration diagram of the pulper control device of the second embodiment Configuration diagram of a conventional pulper control device

Explanation of symbols

1 Pulper, 1A Circulator,
1B Electric motor for pulper, 2 Conveyor,
3 Conveyor motor, 4 Conveyor start switch,
5 Weight detector, 6 Conveyor controller,
8 Concentration setter, 9 White water pipe,
10 valves, 11 flow meters,
12 Flow controller, 13 Level meter,
14 level controller, 15 discharge pipe,
16 discharge pump, 17 densitometer,
18 concentration controller, 19 raw material,
20 switches, 21 pulser drive,
22 speed controller, 24 torque controller,
25 Torque determiner, 26 Minimum value discriminating circuit

Claims (7)

A lump of raw material and white water are put into a pulper and stirred by a circulator, the flow rate of the white water is controlled to control the level of the pulper, and the concentration of the paper material discharged from the pulper is controlled to a predetermined value. In the pulper control device,
A densitometer for detecting the density of the stock;
A second density controller for controlling the density of the paper by comparing a density command and a signal of the densitometer;
A speed control device for receiving a command from the second concentration controller and controlling a rotational speed of the flow circulator;
A pulper control device characterized by comprising:
A density controller for controlling the density of the paper by comparing the density command and the signal of the densitometer;
A conveyor controller that controls the operation of the conveyor according to the input amount output by the concentration controller and inputs the raw material into the pulper;
The pulper control device according to claim 1, further comprising:
A conveyor for transporting the raw material, and a conveyor motor for driving the conveyor;
A conveyor start switch that opens and closes between the conveyor motor and the power source;
A weight detector for detecting the weight of the conveyor and the raw material;
The conveyor controller controls the opening / closing of the start switch for the conveyor by calculating so that an actual input amount obtained from a signal of the weight detector and a constant of the conveyor determined by the conveyor setting device is equal to the input amount command. 3. The pulper control device according to claim 2, wherein the driving of the conveyor is controlled.
When the speed control device (21, 22) receives a speed command, the speed controller (22) outputs the frequency command by operating the circulator (1A) to rotate at a speed corresponding to the speed command; 2. The pulser control device according to claim 1, comprising a pulser drive device (21) that drives a motor (1 </ b> B) connected to the circulating device at the frequency when a frequency command is received. 3.
A lump of raw material and white water are put into a pulper and stirred by a circulator, the flow rate of the white water is controlled to control the level of the pulper, and the concentration of the paper material discharged from the pulper is controlled to a predetermined value. In the pulper control device,
Torque setting value that sets the driving torque of the circulator
A pulper control device comprising a torque controller (24) for giving a speed command to the speed control device based on the detected torque of the circulator output from the speed control device (21, 22).
If the difference between the torque setting value and the detected torque is less than or equal to a predetermined value, a torque determiner (25) that outputs a predetermined speed command, an output of the torque determiner, and an output of the torque controller (24) 6. The pulper control device according to claim 5, further comprising a minimum value discriminating circuit (26) for outputting the smaller one of them.
When the speed controller (21, 22) receives a speed command, the speed controller (22) outputs the frequency command by operating the circulator (1A) to rotate at a speed corresponding to the speed command;
6. The pulper control device according to claim 5, further comprising a pulper driving device (21) that drives the motor (1B) connected to the circulating device at the frequency when the frequency command is received.

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