JPH07116531A - Control method for roller mill - Google Patents

Abstract

PURPOSE:To provide a control method for a roller mill by which the startup of the roller mill is surely performed and also the stationary operating condition is rapidly derived. CONSTITUTION:In startup control, the value of the thickness of a layer of a raw material put between a table 12 and a roller 13 on startup and the value of the vibration of a roller mill 10 at that time are measured, and each measured values are checked against fuzzy variables previously set them to change against quantity of the fed raw material by a rule of control based on fuzzy variables. In rising control to stationary operation, the value of the thickness of the layer of the raw material on startup, the rate of change in the value of the thickness of the layer within a prescribed time from startup, the rate of change in the driving power for the roller mill and the rate of change in the vibration of the roller mill are measured, and each measured values are checked against fuzzy variables previously set against the value of the thickness of the layer and the rate of change in it, the rate of change in the driving power and the rate of change in the vibration to regulate the rate of a rise in the quantity of the fed raw material from the startup to the stationary operation by the rule of control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a roller mill for crushing agglomerates such as cement raw materials and water granulated slag, and more particularly, for a large roller mill in which start-up and startup to normal operation are difficult to control. The present invention relates to a control method for optimally controlling startup and startup.

[0002]

2. Description of the Related Art In a large-sized roller mill, the roller is in a raised position at the time of start-up, and when the operation is started, the roller is lowered and grounded on the raw material initially put on the table. Pressure is applied to the roller and it rotates in cooperation with the rotation of the table,
Crushing of the raw material between the roller and the table is started.
The pressure applied to this roller is gradually increased from the above-mentioned grounded state, and the amount of raw material charged is also increased accordingly. After the pressing force of the roller reaches a predetermined value, the amount of raw material input is increased to a predetermined value for steady operation. As described above, in the roller mill, from the start up to the steady operation, by adjusting the amount of raw material input according to each state, control is performed to prevent the roller mill from excessive vibration and deterioration of product quality. . Conventionally, the control for adjusting the input amount of the above raw materials is
Manual changes were mainly made by the operator.

[0003]

However, with the above-mentioned manual control, it is not easy to follow changes in the amount and quality of the raw material charged into the roller mill at startup, resulting in excessive vibration at startup and the mill motor. In many cases, the start-up fails due to the occurrence of overload, etc., and there was the problem that it was not easy to control the amount of raw material input during start-up. When the vibration exceeds a preset vibration trip set value, the roller mill is forcibly stopped. In the worst case, the vibration may cause a failure of the roller mill, and even if the roller mill is restarted after being forcibly stopped, the product quality is deteriorated for a while after the start. Therefore, in order to prevent breakdowns and quality deterioration, startup must be performed reliably. In addition, the increase in the amount of raw material input from startup to the steady operation state needs to be properly adjusted according to the operating state of the roller mill, and constant program control addresses fluctuations in the amount and quality of raw material. Can not. In addition, labor saving cannot be achieved by relying on monitoring based on the experience of a skilled operator. Considering a great amount of time for training skilled operators, automation of operations from start-up to steady operation is required. It was Therefore, an object of the present invention is to provide a method for controlling a roller mill that surely executes the start-up of a large-sized roller mill that is not easy to start up and quickly leads to a steady operation state.

[0004]

In order to achieve the above object, the first method adopted by the present invention is to lower a roller in a raised position onto a table, and feed a raw material supplied onto the table. A method of controlling a roller mill in which a table is rotated while controlling the amount of the raw material to crush and crush the raw material between the table and the table, when the roller is pressed at a predetermined pressure on the table at startup, A fuzzy variable for the layer thickness value of the raw material sandwiched between the roller and the vibration value of the roller mill at that time and a control rule based on the variable are set in advance, and the layer thickness value and the A method for controlling a roller mill, characterized in that vibration values are measured, each measured value is collated with the set fuzzy variable, and the amount of the raw material input is adjusted based on the control rule. . In the second method, the roller in the raised position is lowered onto the table, the table is rotated while adjusting the amount of the raw material supplied to the table, and the raw material is fed between the roller and the table. In the control method of the roller mill for crushing and crushing the powder, the layer thickness value of the raw material sandwiched between the table and the roller and the layer thickness A fuzzy variable for the change amount, the change amount of the roller mill driving power, and the change amount of the roller mill vibration and a control rule based on the variable are set in advance, and the layer thickness value, the change amount of the layer thickness,
It is characterized in that the amount of change in driving power and the amount of change in vibration are measured, the measured values are collated with the set fuzzy variables, and the rate of increase in the amount of raw material input is adjusted based on the control rule. It is a method of controlling the roller mill.

[0005]

When the roller in the raised position is lowered to a predetermined position on the table at the time of starting the roller mill, if the amount and quality of the raw material supplied on the table fluctuates,
The amount of biting into the roller changes and the vibration value of the roller mill changes. Therefore, it is necessary to adjust the amount of raw material input to increase the amount of raw material in accordance with the situation when the roller is descending. According to the first method of the present invention, the layer thickness value of the raw material sandwiched between the table and the roller at the time of start-up and the vibration value of the roller mill at that time are measured, and the measured value is set in advance as described above. The fuzzy variables set for the layer thickness value and the vibration value are collated with each other, and the feed amount of the raw material is changed according to the control rule based on the fuzzy variables. By controlling by this method, reliable start-up can be performed, and labor saving, compliance with the production plan, and reduction of defects are brought about. In addition, according to the second method, the layer thickness value of the raw material, the variation amount of the layer thickness value, the variation amount of the roller mill driving power, and the variation amount of the roller mill vibration are measured at regular intervals within the period for starting the steady operation. , The measured values are set in advance to the layer thickness value and the amount of change of the layer thickness value at the above-mentioned constant time,
The fuzzy variables set for the amount of change in driving power and the amount of change in vibration are collated, and the rate of increase in the amount of raw material input from startup to steady operation is adjusted by a control rule based on the fuzzy variables. By controlling by this method,
The start-up can be performed reliably and the start-up to steady operation can be performed smoothly.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings for the understanding of the present invention. still,
The following example is an example embodying the present invention and does not limit the technical scope of the present invention. Figure 1
Is a schematic diagram showing a schematic configuration of a roller mill to which the control method according to the present invention is applied, FIG. 2 is a pattern diagram showing a control pattern of a raw material input amount, FIG. 3 is a block diagram showing a starting control method, and FIG. 4 is a fuzzy reasoning. 6 is a graph showing the membership function of the layer thickness value (a) and the vibration value (b) detected for the start control by FIG. 5, FIG. 5 is a graph of the membership function for obtaining the changed value of the initial input amount, and FIG. A block diagram showing a raising control method, and FIGS. 7 to 11 are graphs of membership functions for obtaining the amount of increase or decrease in the amount C ₃ of rise.

First, a schematic structure of a roller mill 10 to which the control method of the embodiment is applied will be described with reference to FIG.
In FIG. 1, the raw material charged through the raw material charging port 14 provided on the side of the mill casing 11 is the mill motor 18
It is dropped on the table 12 which is rotationally driven by.
The raw material put on the table 12 is crushed under pressure with the roller 13 which rotates in cooperation with the table 12. Here, the particles that have been made finer than a predetermined size are
The hot air is blown upward from the hot air generating furnace 16 into the mill casing 11 through the air supply port 21, and is classified into coarse particles and fine particles by the separator 19 which is rotationally driven by the separator motor 20. The fine particles, together with hot air, exit the mill 15 at the upper part of the mill casing 19.
Is guided to the bag filter 22 through the feed duct 17 and collected as a product. On the other hand, the coarse particles fall inside the mill casing 11, are returned to the table 12 and are crushed. Large particles that have not been blown up by the hot air and the raw material overflowing from the table 12 fall to the bottom of the mill casing 11 and are collected on the raw material side by a basket elevator or the like.

In the above structure, the raw material fed from the raw material feeding port 14 is supplied by the conveyor 9, and the feeding amount is controlled by adjusting the feed rate of the raw material by the conveyor 9 by the speed controller 8. Further, the roller 13 is provided on the table 12 when the roller mill 10 is stopped.
It is placed on the upper side of the table, and is lowered at the start of activation, and the hydraulic pressure gradually increases the pressing force in the direction of the table 12 and increases to a predetermined pressing force that enables steady operation. A detector is installed at a required position in order to collect data necessary for controlling the roller mill 10. The roller 1 is used as a detector necessary for performing the control method according to the present embodiment.
3 for detecting the layer thickness value of the raw material sandwiched between the table 3 and the table 12, the vibration sensor 6 for detecting the vibration value of the roller mill 10, and the power of the table motor 18 for rotating the table 12 ( A power sensor 7 for detecting a mil power value is installed. The detection data from each detector is input to the start-up control device 1, and the start-up control device 1 calculates an appropriate raw material input amount corresponding to the situation of the roller mill 10 based on each detection data, and determines the appropriate raw material input amount. The input amount data is output to the speed controller 8 so that The control method at the time of starting the roller mill 10 by the start control device 1 and the startup control method from the startup to the transition to the steady operation will be described below. Note that the control for the steady operation is performed by separately prepared steady operation control software, and when the predetermined raw material input amount is reached by the start control and the start control, the control of the roller mill 10 is performed by the steady operation control software. Is taken over by.

First, a control method for starting the roller mill 10 will be described. In the roller mill 10, when the roller 13 is started, the roller 13 in the raised position starts to descend, and the raw material supply is started by driving the conveyor 9. As shown in the control pattern of FIG. 2, the timing of feeding the raw material by the conveyor 9 is made to coincide with the timing of the lowering of the roller 13, and after a predetermined time T ₁ from the start, the raw material is fed at the initial feeding amount C ₁ . As supplied on the table 12. Therefore, the roller 13 is grounded on the raw material which has been charged with the initial charging amount C ₁ on the table. Since the roller 13 is pressed in the direction of the table 12 by hydraulic pressure after it comes into contact with the ground, it rotates in cooperation with the rotation of the table 12 and starts the crushing and crushing of the raw material sandwiched between the roller 13 and the roller 12. The pressing force of the roller 13 is gradually increased,
It goes down until it becomes a predetermined interval between which the raw material can be properly crushed. If the layer thickness of the raw material when the roller 13 is grounded is not appropriate or the physical properties of the raw material are changed, the vibration of the roller mill 10 increases. If excessive vibration occurs, the roller mill 10 will be forcibly stopped and may fail to start. Therefore, when the roller 13 is grounded, the layer thickness of the raw material sandwiched between the roller 13 and the table 12 is detected by the layer thickness sensor 5, and further, the roller mill 1 at that time is detected.
Vibration 0 is detected by the vibration sensor 6. From the detected values of the layer thickness and the vibration, the change amount ΔC _{1 is} changed so that the initial input amount C ₁ of the raw material becomes an appropriate value. This change amount ΔC ₁
3 is determined by fuzzy inference using the detected layer thickness value and vibration value as input data.

The control by the above fuzzy reasoning is shown in FIG.
As shown in (a) and (b), a membership function corresponding to each detected value of the detected layer thickness value (a) of the roller 13 and the vibration value (b) is set, and this is set. by collating the change amount of the membership functions shown in FIG. 5, to output a change value [Delta] C ₁ initial charge amount C _1. The fuzzy variables that determine the above-mentioned input variables and the corresponding outputs are set as shown in Table 1.

[Table 1] The control rules for the change amount ΔC ₁ of the initial input amount C ₁ corresponding to the fuzzy variable due to the layer thickness value and the vibration value are set as shown in Tables 2 and 3 below.

[Table 2]

[Table 3] When the layer thickness value and the vibration value are detected by the layer thickness sensor 5 and the vibration sensor 6, the change amount of the initial input amount is changed according to the control rules for the layer thickness value and the vibration value shown in Tables 2 and 3 above. ΔC ₁ is obtained from the membership function of the change amount ΔC ₁ shown in FIG. Activation control apparatus 1, since the initial input amount C ₁ in the determined change amount [Delta] C ₁ outputs the data change amount [Delta] C ₁ to speed controller 8 so as to be changed, the speed controller 8 conveying speed of the conveyor 9 To adjust the input amount of raw material to an appropriate value.

As described above, the initial amount of the raw material charged is appropriately changed based on the layer thickness value and the vibration value detected when the roller 13 is grounded, so that the roller mill 10 is caused to generate excessive vibration. It can be started without any trouble, and the failure of starting can be prevented, and the deterioration of the product quality and the failure of the roller mill due to the forced stop due to excessive vibration can be prevented. In the control method at the time of starting, the control method based on the layer thickness value and the vibration value detected when the roller 13 is in contact with the ground has been described. Further, as shown in FIG. It is also possible to perform control in which the power of the roller mill 10, that is, the value of the mill power is added as detection data. When the roller 13 touches the ground, the roller 1
3, the change in the biting amount, that is, the change in the work amount occurs. Therefore, as shown in FIG. 1, the change in the mill power is detected by the power sensor 7, and the above-mentioned data is obtained based on the data obtained by adding the power to the layer thickness and vibration. Fuzzy inference is performed in the same manner as above, and the initial input amount C ₁
The change amount ΔC ₁ can be determined. Further, two of the above three detection data can be selected as control data. After the grounding of the roller 13, the roller 13 is pressurized by hydraulic pressure, and is lowered to a predetermined interval where the raw material can be pinched and crushed between the roller 13 and the roller 12,
The descent of 3 is completed. After the lowering of the roller 13 is completed,
As shown in FIG. 2, the input amount of the raw material is gradually increased to a preset input amount C ₂ . Rate of increase in input amount C during this period
_3, the control of the C ₄ are in accordance with the operating state of the roller mill 10, decrease amount [Delta] C ₃ in each case is done by determining the [Delta] C _4.

Next, the amounts of the above raw materials added are increased by C ₃ , C
The control method for the startup control to the steady operation, which is increased in step ₄ , is explained below. The rate of rise C ₃ is the rate of rise C ₄ during the period including the time T ₂ until the hydraulic system stabilizes after the pressure of the roller 13 is lowered by the hydraulic pressure to a predetermined pressure after the completion of the lowering of the roller 13. Is the rate of increase from the rate of increase C ₃ to the input amount C ₂ for steady operation, and the rate of increase C ₃ is set larger than the rate of increase C ₄ . These rate of increase C ₃ , C ₄
Is set based on the data collected from the operation results of the same type roller mill. For the control of the rising rates C ₃ and C ₄ , the change amount of the layer thickness, the change amount of the vibration, and the change amount of the power consumption (mill power) during the period are calculated to detect the layer thickness at the time of control. Then, based on these calculated values and detected values, fuzzy inference is performed as shown in FIG. 6 to determine the increase / decrease amounts ΔC ₃ and ΔC ₄ of the input amount for each predetermined time. Specifically, the values detected by the layer thickness sensor 5, the vibration sensor 6, and the power sensor 7 shown in FIG. 1 are taken into the start-up control device 1, and the respective amounts of change are calculated at predetermined time intervals. Based on these, the increase / decrease amounts ΔC ₃ and ΔC _{4 for} each predetermined time are determined by fuzzy inference, and the raw material conveying speed of the conveyor 9 by the speed controller 8 is controlled by this data. That is, increase / decrease amount ΔC
₃ and ΔC ₄ are appropriate values according to the state of the roller mill 10 for each predetermined time, and the above-mentioned rising rates C ₃ and C ₄ are changed, and the raw materials in an unstable state during the start-up until steady operation In order to prevent excessive vibration and deterioration of quality of the roller mill 10 due to a change in the amount and quality of the material charged, The fuzzy rule for determining the increase / decrease amounts ΔC ₃ and ΔC ₄ is set by a fuzzy variable according to the relation between the layer thickness and the layer thickness change amount, a fuzzy variable according to the mill power change amount, and a fuzzy variable according to the vibration change amount. To be done. The fuzzy variables shown in each table are the same as those described in Table 1 above.

Membership functions for determining the increase / decrease amount ΔC ₃ based on the fuzzy rules shown in the above tables are, as shown in FIGS. 7 to 10, respectively, a layer thickness (FIG. 7) and a layer thickness change amount (FIG. 8), mill power change amount (FIG. 9), and vibration change amount (FIG. 10). The membership function shown in FIGS. 7 to 10 is applied to the membership function for obtaining the increase / decrease amount ΔC ₃ shown in FIG. 11 to obtain the grade of the membership function with the increase / decrease amount ΔC ₃ . The increase / decrease amount ΔC ₃ obtained here is added to the current input amount. By performing this control at every predetermined time, the rate of increase C ₃ corresponding to the operating state of the roller mill 10 at every predetermined time can be obtained. The rate of increase C ₄ is also increased / decreased by a predetermined time Δ in the same manner as above.
C ₄ is determined and added to the current input amount. The control of the rise rates C ₃ and C ₄ uses the data of the layer thickness value, the layer thickness change amount within a predetermined time, the vibration change amount, and the mill power change amount. The same control as above can be performed by the added six data. It is also possible to control based on four data obtained by extracting arbitrary data from these six data.

[0014]

As described above, according to the control method of the present invention, the layer thickness value of the raw material sandwiched between the table and the roller at the time of starting and the vibration value of the roller mill at that time are measured. The measured value is collated with a fuzzy variable set in advance for the layer thickness value and the vibration value, and the feed amount of the raw material is changed according to the control rule based on the fuzzy variable. Therefore, by controlling by this method, reliable start-up can be performed, and labor saving, compliance with the production plan, reduction of defects, etc. are brought about. Claim 1 corresponds to this. or,
Similarly to the above, the layer thickness value of the starting material, the rate of change of the layer thickness value within a predetermined time from the start, the rate of change of the roller mill driving power, and the rate of change of the roller mill vibration were measured, and these measured values were set in advance as described above. Layer thickness value and rate of change of layer thickness value, rate of change of driving power,
The rate of change in vibration is compared with the set fuzzy variable, and the rate of increase in the amount of raw material charged from startup to steady operation is adjusted by a control rule based on the fuzzy variable. Therefore, by controlling by this method, the start-up can be surely performed and the start-up to the steady operation can be smoothly performed. Claim 2 corresponds to this.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a roller mill to which a control method of the present invention is applied.

FIG. 2 is a pattern diagram showing a control pattern of a raw material input amount.

FIG. 3 is a block diagram showing a startup control method.

FIG. 4 is a graph showing a membership function of a layer thickness value (a) and a vibration value (b) detected for activation control by fuzzy reasoning.

FIG. 5 is a graph of a membership function for obtaining a changed value of the initial input amount.

FIG. 6 is a block diagram showing a startup control method.

FIG. 7 is a graph of a membership function (layer thickness value) for obtaining the amount of increase / decrease in the rate of increase C ₃ .

FIG. 8 Same as above (amount of change in layer thickness).

FIG. 9 Same as above (mill power change amount).

FIG. 10 Same as above (amount of change in vibration).

[FIG. 11] Same as above (increase / decrease amount ΔC ₃ ).

[Explanation of symbols]

 1 ... Startup control device 5 ... Layer thickness sensor 6 ... Vibration sensor 7 ... Power sensor 8 ... Speed controller 9 ... Conveyor 10 ... Roller mill 12 ... Table 13 ... Roller 14 ... Raw material input port

Claims (2)

[Claims] 1. A roller in a raised position is lowered onto a table, and the table is rotated while adjusting an input amount of the raw material supplied onto the table so as to clamp the raw material between the roller and the table. In a control method of a roller mill for crushing, when starting, the layer thickness value of the raw material sandwiched between the table and the roller when the roller is pressed on the table with a predetermined pressure, and the vibration value of the roller mill at that time. A fuzzy variable for and and a control rule based on the variable are set in advance, the layer thickness value and the vibration value are measured when the roller mill is started, and each measured value is collated with the set fuzzy variable, A method of controlling a roller mill, characterized in that the amount of the raw material charged is adjusted based on the control rule. 2. A roller in a raised position is lowered onto a table, and the table is rotated while adjusting an input amount of the raw material supplied onto the table so that the raw material is pinched between the roller and the table. In the control method of the roller mill for crushing, the layer thickness value of the raw material sandwiched between the table and the roller and the change amount of the layer thickness value at every constant time within the start-up period during which the start-up is changed to the steady operation. A fuzzy variable for the variation amount of the roller mill driving power and a variation amount of the roller mill vibration and a control rule based on the variable are set in advance,
The layer thickness value, the layer thickness change amount, the drive power change amount, and the vibration change amount are measured at each of the above-mentioned fixed times, and each measured value is collated with the set fuzzy variable to determine the amount of the raw material input. A method for controlling a roller mill, characterized in that the rate of rise is adjusted based on the above control rule.