JPH0456672B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an operation control device for a grinding system, and in particular, to prevent the grinding system from being unable to operate due to a clogging phenomenon, and to prevent the grinding system from operating in the same system. This invention relates to an improved system that automatically optimizes the settings of a plurality of grinding systems.

[Background of the invention and its problems]

Generally, the operation control device for a grinding system such as a ball mill uses a CFW constant flow rate control method using a so-called constant feedway (hereinafter referred to as CFW) to control the amount of material to be ground fed into the grinding system. Ta. However, since this method does not take into account changes in the operating conditions of the grinding system, it is not always possible to obtain satisfactory control results.

For this reason, recent efforts have been made to detect physical quantities that change according to the operating conditions of the crushing system and to keep them constant.
A CFW flow rate variable control system that variably controls the CFW flow rate is adopted.

By the way, especially in the case of a grinding system that uses a ball mill, during its operation, an undesirable clogging phenomenon called mill clogging causes the material to be ground to stay inside the mill and leave the mill as a ground material. There may be a situation where it is no longer being discharged,
Eventually, the vehicle often becomes inoperable. In particular, in the latter method, when the so-called bucket elevator load value is controlled as a physical quantity, the bucket elevator load value detected in a state where the mill is prone to clogging becomes small, so the amount of material to be crushed is This results in a feedback that increases the amount of water, which in turn promotes clogging of the mill. Furthermore, when controlling the mill sound pressure as a physical quantity, even if the reverse action as described above does not occur, the avoidance action is slow and often comes too late. Similar trends can be observed in control using other physical quantities.

If a clogging phenomenon occurs in the grinding system and it takes time to recover from the clogging, not only the operating efficiency of the grinding system will be significantly lowered, but also the quality of the resulting pulverized product will become unstable, resulting in large losses.

In addition, the above CFW flow rate variable control method determines in advance the bucket elevator (BE) current value, mill sound pressure value, etc. when the mill crushes the maximum amount, and provides these as set values to operate the mill. This method maintains conditions at optimal conditions. However, the optimum values of BE current and sound pressure often shift due to changes in the properties of the feed ore, changes over time of the balls in the mill, and other various disturbances (type 1 disturbances). It was impossible to drive.

Recently, in sound pressure control, an invention has been proposed to avoid the influence of stopping and starting an adjacent mill (Japanese Patent Application Laid-open No. 194054/1982). In addition, a method has been proposed in which the optimum point is automatically found by varying the set values of BE current, sound pressure, etc. (Patent Application No. 56-80508
issue).

However, this type of method has the following problems. In other words, it is not only ineffective against process fluctuations (second type disturbance) that occur regardless of the control method, or disturbances that are shorter than the time required for the control system to track them even if they are related to the control method. There was a possibility that the setting value could be changed in the wrong direction.

The first type of disturbance is one that shifts the optimum point of the control set value used to control the amount of ore feed, as shown in FIG. Furthermore, the second type of disturbance is one that increases or decreases the amount of pulverization no matter where the control setting value is placed, as shown in FIG.
This disturbance is normally applied as a common disturbance to all mills when a plurality of mills are operated in parallel in the same system.

[Purpose of the invention]

Therefore, this invention was made in view of the above points, and it is possible to avoid the inoperable state due to the phenomenon of clogging of the grinding system, or to prevent it as much as possible even if such a tendency occurs. By making it possible to recover in a short time, it is possible to improve the operational efficiency as much as possible, and also to improve the quality of the obtained pulverized product as much as possible. When optimizing operating conditions by varying the control settings of multiple grinding systems, it is possible to eliminate type 2 disturbances that are particularly harmful, and it is possible to accurately and quickly search for the optimum point of the settings. The object of the present invention is to provide an extremely good operation control device for a grinding system that has been improved as described above.

[Summary of the invention]

That is, in order to achieve the above object, the present invention includes a detection means for detecting a physical quantity that changes depending on the operating conditions of a crushing system as a controlled signal, and a detection means for detecting a physical quantity that changes depending on the operating conditions of a grinding system, and a detection means for detecting a physical quantity that changes depending on the operating conditions of a crushing system, and a detection means for detecting a physical quantity that changes depending on the operating conditions of a grinding system. and a control system that sends a control signal to the grinding system for a constant value control mode that variably controls the amount of material to be crushed to be supplied to the grinding system based on a target value, and is operated in parallel as the same system. In a grinding system operation control device that variably controls each setting value of a mill so that each grinding amount of each of a plurality of grinding systems is maximized, a first level L in which a controlled signal from the detection means is lower than the target value; _{The L1} level data required to determine that the grinding system is in a state where the grinding system has a tendency to clog when the level has decreased to ₁ or less, and the L1 level data necessary to determine that the grinding system is in a state where the grinding system is in a state where the grinding system is in a state where there is a tendency to clog. a second level L 2 in which the F ₁ level data necessary for setting the amount of crushed material fed to a predetermined low level F ₁ and the controlled signal from the detection means are higher than at least the first level L _{1 ;} A storage means in which _L2 level data necessary for determining that the above-recovered state is a state in which the grinding system has recovered from a state where the grinding system has a tendency to become clogged is stored in advance; a first determining means for determining that the control signal has fallen below the _L1 level data read from the storage means; and temporarily suspending the fixed value control mode in accordance with a determination result by the first determining means. A command is sent from the control system to the grinding system, and a control signal is sent from the control system to the grinding system to give a feeding amount for the grinding system clogging mode set based on the _F1 level data read from the storage means. a feeding amount setting means for the crushing system clogging treatment mode to be sent to the system; and a second means for determining that the controlled signal from the detection means has recovered to the _L2 level data read out from the storage means. a determining means, a command means for sending a command to return to the fixed value control mode from the control system to the crushing system according to a determination result by the second determining means, and a command means for sending a command to the crushing system from the control system to the crushing system for each of the plurality of crushing systems. Each setting value is calculated as the amount of crushing per unit time of the relevant crushing system F _A and the amount of crushing per unit time of the adjacent crushing system.
The present invention is characterized by comprising a control means that performs variable control so that the difference (F _A - F _B ) with respect to F _B is maximized.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to the drawings.

First, a basic example will be explained. In FIG. 1, 10 is a crushing system, which includes a ball mill 11, a bucket elevator 12, a separator 13,
It is comprised of a scale 14, sound pressure detectors 15a, 15b, etc. such as microphones. The crushed clinker, which is the material to be crushed discharged from the ball mill 11, is then transferred to the separator 13 via the bucket elevator 12. The pulverized clinker transferred to the separator 12 is classified here, and a part of it is discharged as a pulverized product from the discharge port 131, and the remainder is returned to the ball mill 11 via the return path 132. Injected.

Further, clinker, which is a material to be crushed, is fed into the ball mill 11 in an amount according to a command by a control signal outputted from a control unit 30 as a control system, which will be described later, using a belt scale 14. .

The bucket elevator 12 is provided with a detector 16 for detecting a driving load (for example, bucket elevator current or electric power) of a motor (not shown) that is a driving source of the bucket elevator 12.

Further, the ball mill 11 is provided with a detector 17 for detecting a mill drive load (for example, electric power consumption E), and the return path 132
A detector 18 is provided for detecting the return amount of crushed clinker.

And each of the detectors 15a, 15b, 16,
Each detection output from 17 and 18 is sent to an analog-to-digital converter (hereinafter referred to as ADC) 31 of a control unit 30 in the grinding system 1.
It is supplied as a controlled signal component that provides a physical quantity that changes according to the zero operating conditions.

On the other hand, the control unit 30 as the control system includes, in addition to the ADC 31, a digital input unit (hereinafter referred to as DI) 32, a central processing unit (hereinafter referred to as CPU) 33, and a read-only memory (hereinafter referred to as ROM). )34
a, random access memory (hereinafter referred to as RAM) 34b, interface 35 and digital-to-analog converter (hereinafter referred to as DAC)
It is composed of 36 mag.

The detection outputs, that is, the controlled signals and the grinding system clogging detection signal components inputted to the ADC 31 are digitized and then supplied to the CPU 33 via the DI 32.

Here, the CPU 33 receives the controlled signal as the input signal and the crushing system clogging detection signal component according to the program contents stored in the ROM 34a.
The so-called PID is based on the target setting value data for the constant value control mode by normal automatic control that is registered in advance in the RAM 34b and each data required in the crushing system clogging treatment mode described later.
By performing calculations and other necessary operations, the so-called
Control signals for the normal constant value control mode and the crushing system clogging treatment mode based on the CFW flow rate variable control method are transmitted to the interface 35 and DAC 36.
The analog signal is converted into an analog signal and supplied to the belt scale 14 in the grinding system 10.

Note that the CPU 33 is supplied with an operation ON or OFF signal from an operation switch 37 via the DI 32.

In addition, the RAM 34b stores target setting value data for the fixed value control mode based on normal automatic control regarding the amount of material to be crushed, as well as data for the respective detectors 15a, 15b, 1 necessary for the crushing system clogging treatment mode.
A state in which the grinding system clogging detection signals from 6, 17, and 18 have fallen below the first level _L1 , which is lower than the target value setting data for the normal constant value control mode, is a state in which the grinding system 10 tends to become clogged. _L1 level data necessary for determining that the grinding system 10 is in a state where it is determined that the grinding system 10 has a tendency to clog, that is, in the grinding system clogging treatment mode, the amount of material to be crushed is set to a predetermined low level. Level F ₁
F ₁ data necessary for setting the above-mentioned detectors 15a, 15b, 16, 17,
A state in which the grinding system clogging detection signal from the grinding system 10 has recovered to at least a second level _L2 higher than the _first level L1 is determined to be a state in which the grinding system 10 has recovered from a state in which it had a tendency to become clogged. The _L2 level data required for this purpose is written.

Next, the operation of the pulverization system operation control device configured as described above will be explained with reference to the flowchart shown in FIG.

That is, in step _S1 , the operation switch 3
7 is turned on, the CPU 33 takes in the operation-on signal and reads out a program for operation control operation from the ROM 34a. First, the startup processing mode of step _S2 is started. Next, the process proceeds to step _S3 , and when the start-up processing mode becomes stable, a transition is made to a fixed value control mode using normal automatic control. Next, the process proceeds to step _S4 , where it is determined whether or not the grinding system 10 is in a state where it has a tendency to become clogged. The judgment in this step _S4 is made by CPU3.
3 reads _L1 level data from the RAM 34b and outputs it to each detector 15a, 15b, 16, 17, 18.
By determining whether or not the crushing system clogging detection signal from the sound pressure detectors 15a and 15b (in particular, the sound pressure detectors 15a and 15b) has fallen below the _L1 level (for example, 60% of the target setting data in constant value control mode). I am treated well. If the judgment in step _S4 is NO, the process returns to step _S4 to continue the constant value control mode and make the same judgment as described above, but if YES, the grinding system 10 tends to be clogged. When it is determined that this is the case, the process proceeds to the next step _S5 , where the constant value control mode is temporarily stopped and the following crushing system clogging treatment mode is performed.

That is, first, in step _S6 , the CPU 33
reads the F ₁ data from the RAM 34b and determines the amount of material to be crushed by F ₁ (for example, 0 in the target value setting data above).
A control signal is sent from the control system 30 to the grinding system 10 to reduce the amount of the powder to a level below 50%). Next,
Proceed to step _S7 , read the _L2 level data from the RAM34b, and confirm that the crushing system clogging detection signal is the corresponding L2 _level data.
(For example, 80% of the above target value setting data) It is determined whether or not the level has been recovered. This step S ₇
If the judgment is NO, return to step _S6 above and keep the feed amount below the _F1 level, but YES
If so, it is determined that the grinding system 10 has recovered from the clogging state, and the process proceeds to the next step _S8 to return to the constant value control mode, and then returns to step _S4 , where it is determined that the grinding system 10 has the same tendency to become clogged as described above. This means that the constant value control mode is continued while repeatedly determining whether or not the current state is present. After performing such fixed value control mode for a desired time, when the operation switch is turned off in step _S9 , the CPU 33 controls the DI3.
The control system 30 receives the operation-off signal via the control system 30 and sends a command to stop the operation control operation to the crushing system 10. This ends the series of operation control operations.

In addition, in the above, the startup processing mode is a mode in which the initial feeding amount required at the start of operation is set, the material to be crushed is actually fed in that amount, and the processing necessary to start the operation control operation is performed. mode. Also, fixed value control mode means that the CPU
33 to each detector 15a, 15b, 16, 1
7, 18 (especially sound pressure detectors 15a, 15b)
This mode is based on normal automatic control performed by the CFW flow rate variable control method so that the controlled signal detected from the RAM 34b is constant based on the target value setting data read from the RAM 34b.

By the way, in the above basic example, it has been explained that it is desirable that the controlled signal and the crushing system clogging detection signal are both detected from the sound pressure detectors 15a and 15b, but the present invention is not limited to this. For example, one of the signals may be from the detector 16 for detecting the load value of the bucket elevator 12, and the other may be from the sound pressure detectors 15a, 15b. In the former case, each of the levels L ₁ , L ₂ and F ₁ is set to a value obtained by multiplying the target value setting data in the normal constant value control mode by a predetermined constant ratio, as described above. In the latter case, each level of L ₁ , L ₂ and F ₁ may be simply set to a predetermined constant value.

In other words, in the grinding system operation control device according to the basic example described above, the grinding system clogging detection signal (controlled signal) is constantly monitored during the normal constant value control mode to speed up the clogging tendency of the grinding system. By detecting this and forcibly reducing the amount of material to be crushed, it is possible to prevent the crushing system from becoming clogged, or to prevent the crushing system from clogging quickly even if it does become clogged. It can be made possible to recover. As a result, it is possible to reliably prevent the grinding system from becoming inoperable due to clogging, thereby improving the operating efficiency as much as possible, and the resulting pulverized product. It becomes possible to improve the quality as much as possible.

FIG. 3 is a schematic configuration diagram showing an embodiment of a crushing device system in which the above-mentioned basic example is applied to multiple crushing systems of the same system.
It is assumed that it is done in the same way as shown in the figure. In the figure, 10 and 20 are crushing systems, and the first crushing system 10 includes a ball mill 11 and a bucket elevator (hereinafter referred to as
(abbreviated as BE) is the separator 13, belt
It is composed of a scale 14, microphones 15a and 15b, and the like. The crushed clinker, which is the crushed material to be crushed, discharged from the ball mill 11 is transferred to the separator 13 by the BE 12.
The pulverized clinker transferred to the separator 13 is classified, a part of which is discharged as a product, and the remainder is fed into the mill 11 again via a return circuit. The clinker, which is the material to be crushed, is transported to a control unit 3 (described later) by means of a belt scale 14.
An amount corresponding to the command from 0 is fed into the mill 11. Note that the BE 12 is provided with a current detector 16 for detecting a drive current (BE current) of a motor (not shown) that is its drive source.

On the other hand, the second crushing system 20 is
Similar to the grinding system of Ball Mill 21, BE22,
It is composed of a separator 23, a belt scale 24, microphones 25a and 25b, a current detector 26, and the like. And the microphone 15a,
Each detection output (sound pressure signal) of the current detectors 15b, 25a, 25b and each detection output (BE current signal) of the current detectors 16, 26 are sent to the control unit 30.
is supplied to

The control unit 30 includes an analog-to-digital converter (hereinafter abbreviated as ADC) 3
1. Digital input unit (hereinafter referred to as DI)
) 32, central processing unit (hereinafter abbreviated as
(abbreviated as CPU) 33, memory 34a, 34b
and an interface 35. The input signal is digitized by the ADC and supplied to the CPU 33 via the DI. CPU3
3 performs various calculations such as PID calculation based on the input signal and the setting values registered in the memories 34a and 34b, and the CPU 33 sends out a CFW flow rate control signal. This CFW flow rate control signal is then given to the belt scales 14 and 24 via the interface 35.

By the way, in the grinding system operation control device using the system with the above configuration, the grinding system clogging treatment mode is the same as the basic example, so other operations will be explained here with reference to the flowchart in FIG. 4. .

First, the memory 3 of the control unit 30
4a, in addition to the program for the crushing system clogging treatment mode as in the basic example above, a program for the setting value optimization mode, which will be described later, is registered. In addition, the memory 34b also stores the control setting values for the first mill 11 (BE current value or sound pressure value) in addition to the above-mentioned data for the crushing system clogging treatment mode, and the control setting values for the second mill 21. It is assumed that it is registered. BE for Mill 11, 21
Characteristic values such as current and sound pressure (microphones 15a, 1
5b, 25a, 25b, current detectors 16, 26, etc.) is input to the control unit 30 as a controlled signal, the CPU 33 performs PID calculation based on the above set values and characteristic values, and calculates the CFW flow rate. A control signal is output. This control signal is for controlling the amount of cranker supplied to the mills 11, 21 so that each characteristic value of the mills 11, 21 becomes equal to the respective set value. Also,
The CPU 33 integrates the grinding amounts of the mills 11 and 21 for a certain period of time. When the cumulative time ends, the average amount of pulverization (amount of pulverization per unit time) F _A and F _B of each of the mills 11 and 21 is calculated.

Next, the average pulverization amounts F _A and F _B are compared,
The difference is calculated. Here, if the mill to be controlled is, for example, the first mill 11, the CPU 33 calculates (F _A - F _B ), and this difference is compared with the difference in the previous average amount of pulverization. Then, the above difference (F _A
-F _B ) is larger than a specified value. If the amount of change is greater than the specified value,
The set value of the first mill 11 is changed and the process returns to the initial process. In other words, the above set value is the difference (F _A −
F _B ) is changed so that it becomes larger. Furthermore, if the amount of change is smaller than a specified value, the above process is repeated with the same settings up to a specified number of times. If the amount of change is smaller than the specified value for more than the specified number of times,
The setting value of the first mill 11 is considered to be optimized,
The mill to be controlled is switched from the first mill 11 to the second mill 21. Then, in the same way as above, the second
The settings of the mill 21 continue to be changed until the settings are optimized. In this case, the difference in the average amount of pulverization is calculated as (F _B - F _A ).

When the set value of the second mill 21 is optimized, the mill to be controlled is switched to the first mill 11 again.
From then on, by repeating this operation, mill 1
Optimization control is performed for each setting value of mills 11 and 21, so that mills 11 and 21 are always operated under optimal conditions.

Thus, according to this embodiment, in addition to the crushing system clogging treatment mode in the basic example, a plurality of mills 11,
Since the optimal point of the setting values of 21 can be searched for accurately and quickly, the mills 11 and 21 can be operated stably with high efficiency. This effect will be specifically explained with reference to FIG. 5 as follows.

That is, suppose that the mill had been operating at the sound pressure optimum point x ₁ until a certain point t ₀ , but this optimum point changed significantly due to a change in the feed ore and became x ₂ . At this time, if a type 2 disturbance that increases the amount of all mill grinds is simultaneously introduced, in the conventional method, this increase may be interpreted as a result of accidentally changing the sound pressure to a lower value. In this case, the sound pressure setting value is continuously lowered during the period when the disturbance has a slope of ten, and the sound pressure setting value deviates significantly from the true optimum point _x2 . Therefore, it takes a lot of time to find the true optimal point _x2 . This state is shown by a broken line P in FIG. On the other hand, in this embodiment, which evaluates the difference between adjacent mills, unnecessary type 2 disturbances that apply equally to each mill are eliminated, so a new optimal point x ₂ is created as shown by the solid line Q in FIG. can be found quickly. It has also been confirmed that the optimum point search speed of this embodiment is faster even for random disturbances with a frequency comparable to the sampling period.

Note that the present invention is not limited to the embodiments described above. For example, the grinding system is not limited to a ball mill, and various types of mills may be used. Furthermore, it goes without saying that the number of mills is not limited to two, but can be changed to three or more as appropriate. In this case, the setting value of the target mill may be changed based on the difference in the amount of grinding between the target mill and the mill adjacent to the target mill, and the target mill may be sequentially switched to other mills. Further, the physical quantity determined as the set value is not limited to BE current, sound pressure, etc., and may be any value that changes depending on the operating conditions of the mill.
Moreover, as a value for evaluation, it is possible to use electric power consumption E instead of the amount of pulverization. In this case, instead of maximizing (F _A − F _B ), (E _A − F B )
Control should be performed to minimize E _B ). In addition, various modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

Therefore, as described in detail above, according to the present invention, it is possible to prevent an inoperable state due to a clogging phenomenon in the grinding system, or even if such a tendency occurs, it can be prevented in the shortest possible time. By making it possible to recover with When optimizing the operating conditions by varying the control settings of the grinding system, it is possible to eliminate particularly harmful type 2 disturbances, and to search for the optimum point of the settings accurately and quickly. Therefore, it is possible to provide an extremely good operation control device for a grinding system that has been improved in this way.

[Brief explanation of the drawing]

Fig. 1 is a configuration explanatory diagram showing a basic example of the operation control device for a grinding system according to the present invention, Fig. 2 is a flowchart for explaining the operation of Fig. 1, and Fig. 3 is an illustration of the basic example to which the above basic example is applied. A schematic configuration diagram showing a pulverizer system according to an embodiment of the present invention, FIG. 4 is a flowchart for explaining the operation control method of the above system, and FIG. 5 is a schematic diagram for explaining the effect of the above method. , FIG. 6, and FIG. 7 are schematic diagrams for explaining changes in the optimum point of the set value due to various disturbances. 10,20...Crushing system, 11,21...Ball mill, 12,22...Bucket elevator, 1
3, 23... Separator, 14, 24... Belt scale, 15a, 15b, 25a, 25b
... Sound pressure detector (microphone), 131 ... Exhaust port, 132 ... Return path, 16, 17,
18, 26...detector, 30...control/
Unit (control system), 31...ADC, 32...
DI, 33...CPU, 34a...ROM, 34b...
...RAM, 35...Interface, 36...
DAC, 37...operation switch.

Claims (1)

[Claims] 1. A detection means for detecting a physical quantity that changes depending on the operating conditions of the grinding system as a controlled signal, and a detection means for detecting the amount of material to be ground to be supplied to the grinding system so that the controlled signal from this detection means is constant. and a control system that sends a control signal for a fixed value control mode that is variably controlled based on a target value to the grinding system, and the grinding amount of each of the plurality of grinding systems operated in parallel as the same system is the maximum. In an operation control device for a grinding system that variably controls each setting value _of a mill so that L ₁ level data necessary for determining that the state is in a tendency to clog, and the amount of the material to be crushed to be fed is set to a predetermined low level F ₁ in a state in which the grinding system is determined to be in a state in which there is a tendency to clog. The crushing system is determined to have a tendency to become clogged when the F1 level data necessary for setting the _F1 level and the controlled signal from the detection means have recovered to at least the second level _L2 which is higher than the first level _L1 . storage means in which _L2 level data necessary for determining that the state has recovered from the state in which the L2 level data has been recovered; and the _L1 level data from which the controlled signal from the detection means is read out from the storage means. a first determining means for determining whether the level has fallen below the level data; and a command for temporarily stopping the constant value control mode from the control system to the crushing system in accordance with the determination result of the first determining means. In addition, a control signal for a crushing system clogging treatment mode is sent from the control system to the crushing system to give a feed amount for the crushing system clogging mode set based on the _F1 level data read from the storage means. a feeding amount setting means; a second determining means for determining whether the controlled signal from the detecting means has recovered to the _L2 level data read from the storage means; and a determination by the second determining means. a command means for sending a command from the control system to the grinding system to return to the fixed value control mode according to the result; Amount F _A and the amount of grinding per unit time of the grinding system adjacent to it
1. An operation control device for a crushing system, comprising: a control means for variable control so that the difference (F _A - F _B ) with respect to F _B is maximized.