JP3121129B2 - Powder production equipment with bulk density control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a granular material with bulk density control in a granular material production plant.

[0002]

2. Description of the Related Art In a powder production apparatus for continuously supplying a powder material to a mixer, control of the bulk density of the obtained powder is a very important factor from the viewpoint of quality control.

[0003] For example, in the case of using a continuous mixer of a type having a stirring shaft inside a mixing tank and attaching a stirring blade to the shaft to mix powder and granules, a conventional operation method is as follows.
For a while after the start of operation, the retention amount adjusting member is set to a certain value based on past operation results, and then the operator checks the change in the value of the bulk density meter or other process data correlated with the bulk density value. There is known a method of adjusting the bulk density by manual operation, such as changing the setting of the retention amount adjusting member based on the experience of the above.

[0004]

However, directly,
Whether to change the setting of the stagnation amount adjustment member by the change in the bulk density value, or to change the setting of the stagnation amount adjustment member by the change of another process data correlated with the bulk density value,
It is up to the driver, and the change cycle varies, and the same change in the bulk density is not always taken in the same manner, so that sometimes an excessive operation may be added.

[0005] Therefore, when the operating conditions are changed due to a composition change or the like, there is a problem that the driving method has no past record as a driver and relies entirely on intuition.

As a conventional technique for improving this, a PI obtained by adding a first-order lag to continuous measurement values from a bulk density meter is used.
By the D control, for example, a method of continuously and automatically controlling the setting of the stay amount adjusting member described above is widely used. However, the time delay of the plant cannot be accurately simulated, or the measured value of the bulk density meter is continuously measured. If a continuous input cannot be obtained, it is impossible to set a control cycle, and practical automatic control is impossible.

Further, in order to manage a plurality of plants with a small number of operators, it is impossible to constantly monitor and adjust the fluctuation of the bulk density value. As described above, there is a problem that the effect is extremely low even if the conventional control method is adopted and automated.

The present invention has been made in consideration of the above-mentioned problems. By inputting the operation knowledge of a skilled driver as a fuzzy production rule, the residence time of the granular material is controlled, and the bulk density is set to a predetermined reference value. An object of the present invention is to provide an apparatus for producing a granular material with bulk density control of the granular material to be stabilized.

[0009]

FIG. 1 is a block diagram showing the basic configuration of the present invention. As shown in FIG. 1, the present invention relates to a mixer having a powder supply port, a powdery material discharge port, a mixing tank for mixing powder, and a retention amount adjusting member for adjusting the amount of powder retained in the mixing tank. 101, a powder feeder 102 that continuously supplies a powder material to a powder feed port of the mixer 101, and a bulk density measuring unit that measures the bulk density of the powder discharged from the powder discharge port 103 and a fuzzy calculating means for calculating the staying amount adjustment value of the staying amount adjusting member by fuzzy inference in order to control the formed granular material to a predetermined bulk density value using the measured bulk density value 104 and control means 10 for controlling the stay amount adjusting member to the calculated stay amount adjustment value
5 is a powder-particle production apparatus with bulk density control, comprising:

In the above configuration, the fuzzy calculating means 104 calculates the change rate of the bulk density from the bulk density value of the granular material, performs fuzzy inference using the bulk density value and the change rate of the bulk density, Preferably, it is configured to calculate an adjustment value.

The fuzzy calculating means 104 calculates a moving average value of the bulk density value of the granular material, makes a fuzzy inference using the moving average value of the bulk density value and the rate of change thereof, and calculates the staying amount adjustment value. More preferably, it is configured to calculate.

Further, as shown in FIG. 2, a supply flow rate measuring means 106 for measuring a supply flow rate value of the powder supplied from the powder supply device is further provided, and the fuzzy operation means 10 is provided.
4 may be configured to calculate the rate of change from the measured supply flow rate value, perform fuzzy inference using the bulk density value and the change rate of the supply flow rate value, and calculate the retention amount adjustment value.

Further, there is further provided a supply flow rate measuring means for measuring a supply flow rate value of the powder supplied from the powder supply device, and the fuzzy calculating means 104 comprises a moving average value of the bulk density and a change rate of the bulk density. Most preferably, fuzzy inference is performed from the rate of change of the supply flow rate to calculate the retention amount adjustment value.

In the present invention, the mixer 101
For example, a generally known type in which a powder supply port, a granular material discharge port, and a mixing tank are provided, and a stirring shaft having a stirring blade attached inside the mixing tank is used to mix powder. Is used. This mixer 101 is provided with a retention amount adjusting member for adjusting the bulk density of the powder raw material at the powder / particle discharge port. As the stay amount adjusting member, a gate for adjusting the discharge amount of the granular material discharged from the granular material discharge port is used.

The powder feeder 102, for example, mixes the powder raw material continuously sent from the powder raw material manufacturing equipment with the mixer 10
It is preferable that the apparatus is provided with a quantitative supply control device capable of continuously and quantitatively supplying to one supply port and a powder flow rate measuring device for measuring a powder supply flow rate.

As the bulk density measuring means 103, for example,
Sampling type bulk density measurement device (for example, Takemoto Electric Instruments
(Produced by K.K.). The bulk density measuring means 103 is provided in the flow path of the powder discharged from the powder outlet of the mixer 101.

The fuzzy calculation means 104 includes a CPU (Central Processing Unit) for calculating a moving average value of bulk density and its change rate and a change rate of powder supply amount, and fuzzy inference, and a ROM (Read Only). It is convenient to use a computer system including a memory), a RAM (random access memory), an I / O port, and an external storage device such as a hard disk or a floppy disk.

The control means 105 is a fuzzy arithmetic means 104
The position of the stay amount adjustment member is added to the stay amount adjustment value given by
It is composed of a drive unit that drives the rotation angle and a control unit that controls the position / rotation angle. Further, the drive unit includes a detection unit that detects the position / rotation angle of the stay amount adjustment member.

[0019]

According to the present invention, in FIG.
02, the powder raw material is continuously supplied to the powder supply port of the mixer 101 in a constant amount, and the granules mixed and formed in the mixing tank are continuously discharged from the granule discharge port. The bulk density of the discharged granular material is measured by the bulk density measuring means 103, and the fuzzy calculating means 104 uses the measured bulk density value to divide the formed granular material by the fuzzy inference into the amount of the retained amount adjusting member. By calculating the staying amount adjustment value and controlling the staying amount adjusting member to the calculated staying amount adjustment value by the control means 105, a powder or granular material having a predetermined bulk density value can be obtained.

That is, when the amount of residence is increased by adjusting the residence amount adjusting member, the residence time of the powder in the mixing tank increases, the formation of powder from the powder proceeds, and the bulk density of the powder decreases. Increase. In addition, when the amount of residence is reduced, the state is reversed, and the bulk density of the granular material decreases. In the present invention, the bulk density of the powder is controlled based on this principle.

The fuzzy computing means 104 calculates the rate of change from the bulk density value of the granular material measured by the bulk density measuring means 103, and uses the bulk density value and the rate of change of the bulk density to perform fuzzy inference. Is performed to calculate a retention amount adjustment value. Therefore, the controllability is improved because the change in the bulk density can be detected.

Further, the fuzzy calculating means 104 calculates a moving average value of the bulk density value of the granular material, performs fuzzy inference using the moving average value of the bulk density value and the rate of change thereof, Is calculated, the measurement error of the measured bulk density value is smoothed, so that the controllability is improved.

A supply flow rate measuring means 106 for measuring a supply flow rate value of the powder supplied from the powder supply device 102.
In further provided, said fuzzy computation unit 104 calculates a rate of change from the measured feed amount value, performs a fuzzy inference using the bulk density change rate of the supply flow rate to calculate a retention amount adjustment value constitutes a If it is, fluctuations in the supply flow rate can be captured, so that fuzzy control with good controllability can be performed.

A supply flow rate measuring means 106 for measuring the supply flow rate value of the powder supplied from the powder supply device 102.
The fuzzy calculation means 104 performs fuzzy inference using the moving average value of the bulk density, the change rate of the bulk density, and the change rate of the supply flow rate, and calculates the retention amount adjustment value. Fuzzy control can be performed because the fluctuation of the flow rate, the measurement error of the bulk density value, and the fluctuation of the supply flow rate can all be captured.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. The present invention is not limited by this.

FIG. 3 is a block diagram showing one embodiment of the apparatus for producing a powdery substance with bulk density control according to the present invention. In FIG. 3, one or more powder raw materials continuously supplied from a powder raw material manufacturing facility 1 are quantitatively mixed by a mixer 3 by one or more powder quantitative feeders 2. The mixture is supplied to the tank, and a stirring shaft is provided inside the mixing tank of the mixer 3, and a stirring blade is attached to the shaft to mix the powder and produce powder and granules.

At the discharge port of the mixing tank, there is provided a stagnation amount adjusting member 4 for adjusting the bulk density of the granular material. The stagnation amount adjusting member 4 is connected via a link / gear to operate the stagnation amount adjusting member 4. It has a drive unit 5 (for example, a servomotor) and a controller 6 for controlling the drive unit 5.

A bulk density meter 7 for measuring the bulk density of the granular material is provided in the flow path of the granular material. The powder metering device 2 is provided with a powder flow meter 8 for measuring a supply flow rate (input flow rate) of the powder supplied to the mixing tank. When a plurality of powders are continuously charged into the mixing tank, the input flow rate is adjusted to a constant flow rate by the powder quantitative supply device 2 for each powder. By adding the instantaneous flow rates of the powder metering device 2, the flow rate of the powder charged into the mixing tank is calculated.

The control computer 9 calculates the retention amount adjustment value (operating amount / gate opening degree) from the bulk density value of the granular material measured by the bulk density meter 7 and the supply flow rate (input flow rate) measured by the powder flow meter 8. ) Is fuzzy inferred, and when this stay amount adjustment value is given to the controller 6, the driving unit 5 drives the stay amount adjustment member 4 to control the stay volume density value to the target value.

In the equipment according to the embodiment of the present invention, a gate is used as the staying amount adjusting member 4 for adjusting the bulk density of the granular material. The gate opening is controlled by controlling the rotation direction and the number of rotations. Since the servomotor can detect a value corresponding to the rotation angle, feedback control is performed by the controller 7 so that the detected value matches the gate opening set value.

By opening the gate, the amount of residence is reduced and the bulk density value is reduced, and by closing the gate, the amount of residence is increased and the bulk density value is increased. That is,
The target bulk density value can be obtained by controlling the gate with the controller 7 at the gate opening (retention amount adjustment value) given from the control computer. The powder and granules thus generated to the target bulk density value are continuously supplied to the next step.

In such a continuous equipment, it is necessary to balance the production capacity of the powder raw material manufacturing equipment 1 with the processing capacity of the present equipment. It is changed by the weight-reduction-type quantitative supply control device provided in the main body of the powder quantitative supply device 2 in a cycle.

FIG. 4 is a block diagram showing the configuration of the control computer shown in FIG. 3 and the flow of input / output signals. As shown in FIG. 4, the control computer 9 includes an input / output unit 91, an auxiliary storage unit.
92, a main storage unit 93, and a central processing unit 94. The input / output unit 91 reads input data such as the bulk density value measured by the bulk density meter 7 and the input flow rate value of the granular material, and controls the data processing for passing the data to the central processing unit 94 and the gate of the mixer 3. Gate opening output to controller 6, powder metering machine 2
Performs output data processing of set values for changing the input flow rate of

The auxiliary storage unit 92 is a storage device such as a hard disk, a floppy disk, or a tape in which a file in which fuzzy production rules for fuzzy operation and membership functions are registered is stored. Main memory 93
Is an area for reading and storing membership functions and fuzzy production rules registered in the auxiliary storage unit 92, an area for storing input / output data such as bulk density value, powder input flow rate value, gate opening degree, and data being processed. RO consisting of
A storage device such as an M, a RAM, a hard disk, or a floppy disk.

The central processing unit 94 converts the data such as the moving average value of the bulk density, the rate of change thereof, and the rate of change of the input flow rate into a fuzzy calculation program by numerical conversion and fuzzy calculation, and converts the calculation result into a gate opening. To perform change processing on
U, a ROM / RAM in which an I / F program 94a for processing and numerically converting input / output data and a fuzzy inference program 94b for performing fuzzy arithmetic processing based on membership functions and fuzzy production rules, and transfer of each program / data It is composed of a computer system consisting of I / O ports.

FIG. 5 is a flowchart showing an embodiment of the bulk density fuzzy control according to the present invention. In FIG. 5, the bulk density of the granular material is inferred from the moving average value of the bulk density value of the granular material, its rate of change, and the rate of change of the input flow rate by fuzzy inference to the gate opening (set opening) of the gate. An embodiment of the fuzzy control will be described with reference to FIGS.

The processing from step S10 to step S50 is performed by I /
This is executed when the bulk density measurement is completed by the F program. Step S10: It is determined whether or not the measurement of the bulk density value of the granular material by the bulk density meter has been completed. Step S20: If the measurement of the bulk density value is completed, the measured bulk density value of the powder and the input flow rate value measured by the powder flow meter 8 are input to and read from the input / output unit.

Step S30: The read bulk density measurement value is subjected to moving average processing. Here, in the measurement of the bulk density by the bulk density meter 7, the sample period of the bulk density meter 7 and the delay time of the plant are taken into account, and the moving average is calculated due to the variation of the powder sample and the measurement error of the bulk density. Preferably, a moving average of five bulk densities measured every 90 seconds was used in this example. By performing this moving average, the fluctuation of the bulk density is smoothed and the controllability is improved. Further, the update of the gate opening set value by the fuzzy inference of the present invention is also performed every 90 seconds (step S60).

Step S40: The change rate of the bulk density is calculated, and the change rate of the input flow rate of the powder is calculated. By using the rate of change of the bulk density and the rate of change of the amount of powder input, fluctuations in the bulk density are captured and controllability is improved. Step S50: Since the moving averaged value and the change rate need to be evaluated with the same weight when performing fuzzy inference, each is normalized to a value of -1 to 1.

The processing in steps S60 to S80 is processed by a fuzzy inference program. Step S60: After normalization, a fuzzy operation is performed by a membership function, a fuzzy production rule, and a fuzzy inference program registered in the auxiliary storage unit.

The driving know-how of a skilled driver is replaced by fuzzy production rules, and the following rules are used.
Rules 1 to 15 are determined. Rule 1: If the high density value is considerably large, the gate opening is greatly increased. Rule 2: If the bulk density value is slightly large, the gate opening is slightly opened. Rule 3: If the bulk density value is just right, the gate opening is kept as it is. Rule 4: If the high density value is slightly smaller, close the gate opening slightly. Rule 5: If the high density value is very small, close the gate opening considerably.

Rule 6: If the rate of change of the high density value is fairly large, the gate opening is greatly increased. Rule 7: If the change rate of the high density value is slightly larger, the gate opening is slightly opened. Rule 8: If there is no change in the high density value, the gate opening is kept as it is. Rule 9: If the rate of change of the high density value is slightly negative, the gate opening is slightly closed. Rule 10: If the rate of change of the high density value is negatively large, the gate opening is closed considerably.

Rule 11: If the rate of change of the input flow rate is quite large, close the gate opening considerably. Rule 12: If the rate of change of the input flow rate is slightly larger, close the gate slightly. Rule 13: If the input flow rate does not change, keep the gate opening as it is. Rule 14: If the rate of change of the input flow rate is slightly negative, open the gate slightly. Rule 15: If the rate of change of the input flow rate is negatively large, the gate opening is considerably increased.

The fuzzy calculation is described in detail in Nikkan Kogyo Shimbun, "Fuzzy Control" (Michio Sugano), pp. 76-84, which can be referred to.

FIG. 6 is an explanatory diagram showing the membership function of the input and output of the gate opening in the present invention. In FIG. 6, the reference value of the membership function of the bulk density value indicates a case where the reference value of the bulk density of the powder obtained by the mixer 3 is 0.0. In order to cope with the change of the reference value, a membership function having a horizontal axis obtained by normalizing the actual numerical value from “−1.0” to “+1.0” is used. The rate of change of the bulk density value,
The change rate of the input flow rate indicates a value in the range of -1.0 to +1.0, and the gate opening operation amount indicates a numerical value in the range of -1.0 to +1.0.

FIG. 7 shows a situation inferred by the above fuzzy production rules and membership functions. FIG. 7 is an explanatory diagram showing a fuzzy calculation process of the gate opening in the present invention. In FIG. 7, before the fuzzy arithmetic processing is performed by the fuzzy inference program, step S20,
From the input data of the bulk density moving average value, the bulk density change rate, and the input flow rate change rate calculated in the processing steps of S30, S40, S40, S50, the degree of conformity calculated from the membership function based on each fuzzy production rule from the input data. The operation amounts are overlapped, and the center of gravity of the area is obtained as the inference result.

Here, for example, an inference result is obtained by performing a MIN operation on the membership function of the manipulated variable calculated from the bulk density value at this time and the rule 2 of the matching situation (FIG. 7-1). Similarly, an inference result is obtained by performing a MIN operation on the membership function of the manipulated variable calculated from the bulk density change rate and the rule 10 of the matching situation (FIG. 7B). Similarly, the rate of change of input flow rate and the rules of conformity
An inference result is obtained by performing a MIN operation on the membership function of the manipulated variable calculated from FIG.
3). Superposition of manipulated variables of inference results of each rule (Fig. 7
-4), a MAX operation is performed on the result obtained by superposing the inference results of the respective rules (total area is obtained) to obtain an overall inference result (FIG. 7-5). Finally, the center of gravity of the comprehensive inference result is obtained, and the obtained gate opening / operation amount is used as an output of the input / output unit 91 (X coordinate of the center of gravity in FIG. 7-6).

Step S70: However, the operation result is -1 to 1
Since this value is a unitless value, the value is denormalized as a gate opening change width, and the result is added to or subtracted from the current gate opening to obtain a set opening (operation amount). Step S80: The set opening is given to the controller 6 that controls the gate.

Accordingly, the above-mentioned steps S10 to S
By repeating the process of step 80, the set opening degree is given to the gate in a timely manner, so that the retention amount of the powder in the mixing tank is changed to obtain the target bulk density value.

[0050]

According to the present invention, it is possible to automatically control the bulk density control operation of a granular material in a granular material manufacturing plant, which has conventionally been performed based on the driver's intuition and experience, with high precision. In addition, in the bulk density fuzzy control, a moving average of the bulk density value and a change rate of the bulk density are calculated from the bulk density value measured at a predetermined cycle, and a change in the bulk density caused by a change in the powder supply flow rate. By measuring the fluctuation of the powder supply flow rate to avoid the fluctuation, calculating the rate of change of the powder supply flow rate and using it as an input of fuzzy inference, it is possible to capture the fluctuation of the bulk density and further improve the controllability. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram showing another basic configuration of the present invention.

FIG. 3 is a block diagram showing one embodiment of a powder production apparatus with bulk density control according to the present invention.

4 is a block diagram showing the configuration of the control computer shown in FIG. 3 and the flow of input / output signals.

FIG. 5 is a flowchart showing an embodiment of bulk density fuzzy control according to the present invention.

FIG. 6 is an explanatory diagram showing a membership function of input / output of a gate opening in the present invention.

FIG. 7 is an explanatory diagram showing a fuzzy calculation process of a gate opening in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Powder raw material manufacturing equipment 2 Powder quantitative feeder 3 Mixer 4 Retention amount adjusting member (gate) 5 Drive unit 6 Controller 7 Bulk density meter 8 Powder flow meter 9 Control computer 91 Input / output unit 92 Auxiliary storage unit 93 Main Storage unit 94 Central processing unit 94a I / F program 94b Fuzzy inference program

Continuation of front page (56) References JP-A-4-222628 (JP, A) JP-A-57-91732 (JP, A) JP-A-54-157775 (JP, A) JP-A-54-110180 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B01J 2/00 B01J 2/10

Claims (5)

(57) [Claims] 1. A mixer having a powder supply port, a powder outlet, a mixing tank for mixing powder, a retention amount adjusting member for adjusting the amount of powder retained in the mixing tank, and a powder of the mixer. A powder feeder for continuously supplying a powder raw material to the body supply port, a bulk density measuring means for measuring the bulk density of the powder discharged from the powder outlet, and a measured bulk density value. Fuzzy computing means for calculating the staying amount adjustment value of the staying amount adjusting member by fuzzy inference in order to control the formed granular material to a predetermined bulk density value using the calculated staying amount adjustment value. An apparatus for producing a granular material with bulk density control, comprising: a control means for controlling a retention amount adjusting member. 2. The fuzzy calculating means calculates a rate of change of the bulk density from the bulk density value of the granular material, performs fuzzy inference using the bulk density value and the rate of change of the bulk density, and calculates a retention amount adjustment value. The apparatus for producing a granular material with bulk density control according to claim 1, wherein the calculation is performed. 3. The fuzzy calculating means calculates a moving average value of the bulk density value of the granular material, performs fuzzy inference using the moving average value of the bulk density value and its rate of change, and calculates a retention amount adjustment value. The granular material device with bulk density control according to claim 1. 4. A supply flow rate measuring means for measuring a supply flow rate value of the powder supplied from the powder supply device, wherein the fuzzy operation means calculates a rate of change from the measured supply flow rate value, The apparatus for producing a powdery / granular material with bulk density control according to claim 1, wherein fuzzy inference is performed using the bulk density value and the rate of change of the powder supply flow rate to calculate a retention amount adjustment value. 5. A supply flow rate measuring means for measuring a supply flow rate value of the powder supplied from the powder supply device, wherein the fuzzy operation means determines a moving average value of the bulk density, a change rate of the bulk density, and a supply rate. The apparatus for producing a granular material with bulk density control according to claim 1, wherein fuzzy inference is performed from the rate of change of the flow rate to calculate a retention amount adjustment value.