JPS6147627B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for producing a liquid material (e.g., molten metal such as molten copper) from a tilting container (e.g., refining furnace, horizontal cylindrical furnace, etc.) that operates in a tilting manner for the next process. The present invention relates to a device that automatically controls the supply flow rate of a liquid material in a device that continuously supplies a liquid material at a preset flow rate to a device (for example, a casting device, etc.).

A typical example of this type of supply device and manufacturing device is one that supplies molten copper from a refining furnace to a casting device by tilting motion. Below, these devices will be explained by taking them as examples.

In order to continuously perform casting for reasons such as improving productivity, it is necessary to constantly drain an appropriate amount of molten copper from the refining furnace and supply it to the casting apparatus. The amount of molten copper flowing out from the refining furnace depends on the tilting angle and the tilting speed of the refining furnace.

Conventional techniques for controlling the flow of molten copper from a refining furnace to a constant level include the following. That is, the rough adjustment speed command device roughly adjusts the tilting speed in steps in accordance with the tilting angle of the refining furnace. Then, a fine adjustment speed command device is used to compare the weight of the distiller pot measured at regular intervals with the set value of the pot weight, and when the difference exceeds a certain value, the refining furnace tilting speed is finely adjusted. It is something.

By the way, the relationship between the tilting angle and the tilting speed in order to maintain a constant flow rate from the refining furnace should theoretically and ideally be represented by a continuous curve.

However, with conventional equipment, the tilting angle of the refining furnace is detected by a plurality of limit switches placed at appropriate intervals, and the tilting speed is coarsely adjusted in steps based on the relationship between the limit switch positions and detection time. It's becoming like that. Therefore, a large error will occur between the actual adjustment signal and the theoretical value. Additionally, many limit switches are required to improve accuracy. For example, one operation of a refining furnace requires 5 to 8 hours;
If the time is 6 hours (360 minutes), even if one limit switch is used for detection every 5 minutes, a total of 72 limit switches would be required.

On the other hand, when finely adjusting the tilting speed, the stepping relay is switched when the difference between the measured value and the set value of the weight of the reservoir exceeds a certain value.
However, since this operation is performed regardless of the magnitude of the weight difference, it is difficult to improve accuracy.

Furthermore, in the conventional apparatus, the tilting speed is finely adjusted so as to keep the weight of the reservoir constant at regular intervals. However, it is meaningless to control the flow rate by measuring the weight of molten copper in the reservoir at regular intervals. In other words, when flowing out, the flow rate is not necessarily maintained at a constant level due to deformation of the molten copper at the outlet from the refining furnace due to heat, etc., and may vary due to other disturbance factors.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a control device that can suppress fluctuations in the supply amount, that is, the outflow amount, of a liquid material such as molten copper, and can supply the liquid material with high accuracy.

The main features of the present invention are that the tilting angle of the tilting vessel (hereinafter referred to as a refining furnace) is continuously detected, and the basic adjustment of the tilting speed is made continuous using the theoretical formula described below. The point is that accuracy is improved by correcting using a theoretical formula.

Hereinafter, the present invention will be described in detail based on illustrated embodiments. First, a molten copper supply device and a casting device to which the supply flow rate control device of the present invention is applied will be explained.

Outline of the configuration and operation of the molten copper supply device In FIG. Molten copper 2 is once stored in a reservoir 4 and is intermittently discharged to a weighing pan 6 by a reservoir drive device 5. The molten copper 2 stored in the weighing ladle 6 is intermittently and sequentially cast into molds 8, 9, and 10 of the casting device 12 by the weighing ladle driving device 7. As a result, product 11 is produced. It is assumed that the molds 8, 9, and 10 of the casting apparatus 12 move sequentially in the direction of the arrow shown in the figure.

In FIG. 1b, the refining furnace 1 has a cylindrical shape, and tires (a non-drive side tire 13 and a drive side tire 14) are fitted on each of its axial peripheral ends. It is rotatably supported by support rollers (not shown).

The refining furnace 1 is rotationally driven via a ring gear 15 fixed to a driving tire 14. That is,
A pinion 16 is meshed with the ring gear 15,
A main reduction gear 17 is connected to this pinion 16 . A high-speed electric motor 19 is connected to the main reduction gear 17 via a high-speed brake 18 . This high-speed electric motor 19 is used during high-speed operation when driving the refining furnace 1 to rotate at high speed or when pouring blister copper smelted in the converter in the previous step.

Furthermore, the high-speed electric motor 19 is equipped with an electromagnetic clutch 2.
0, a low speed reducer 21, a low speed variable speed electric motor 22, and a low speed brake 23 are connected in series. 24 is a rotating generator for detecting the rotational speed of the electric motor 22. The low-speed variable speed electric motor 22 and its associated devices 21, 23, and 24 described above are used during cooperative operation with the casting device 12. Note that, at this time, the power to the high-speed electric motor 19 is turned off.
The refining furnace 1 is stopped by the low speed brake 23.

Further, a tilt angle detection reducer 25 is connected to the main reducer 17 in order to detect the tilt angle θ of the refining furnace 1 as described later. The speed reducer 25 and the Sershin generator 26 are connected, and the tilt angle signal θ is output from the Sershin transmitter 26 to the Sershin receiver 27.

Related Operations between the Molten Copper Supply Device and the Casting Device First, the operations of the sump 4 and weighing pot 6 will be described (see FIG. 1a). For example, when the mold 9 reaches the casting start position (the position shown in the figure), the weighing pan 6 starts tilting by the weighing pan drive device 7, and the molten copper in the weighing pan 6 is discharged into the mold 9. Ru. At this time, the weighing device 7A provided in the weighing pan drive device 7
The weight of the molten copper in the weighing pan 6 is continuously weighed. When the completion of discharging the weight of molten copper to be poured is detected, the weighing pan 6 is raised and returned to its original standby position in response to a return command.

Naturally, while the molten copper is being poured from the weighing pot 6 into the mold 9, the molten copper is not discharged from the sump pot 4 to the weighing pot 6. This is to accurately measure the casting amount using the weighing device 7A.

By the way, from the time when the weighing pan 6 completes discharging the molten copper until the weighing pan 6 returns to its original standby position, the weighing pan 6 comes into contact with a limit switch (not shown) installed at an appropriate position, and the accumulated copper is removed. A command to start tilting the pot 4 is issued. In response to this start command, the basin 6 starts tilting by the basin driving device 5. and,
At the time when molten copper starts to be discharged from the reservoir 4, the weighing pan 6 has completed casting. Therefore, the weight of the molten copper discharged from the reservoir 4 to the weighing pan 6 is accurately weighed as the received weight by the weighing device 7A. When a predetermined weight of molten copper is stored in the weighing pot 6, the weighing device 7A detects this and outputs a return command to the reservoir pot 4. The basin 4 returns to its original standby position and waits for the next tilt command.

I will explain in more detail. In FIG. 1a, the starting position C is located at a relative distance L from the outlet B of the weighing pan 6, where C is the starting position for receiving molten copper on the molds 8, 9, and 10, and D is the receiving end position. Once there, the control device (not shown) of the casting device 12 sends the weighing pan 6
A tilting start command is issued. Casting ends at position D
is carried out until the position of the relative distance L is reached, and during that time, the casting of a predetermined weight of molten copper is completed. Then, as described above, the weighing pan 6 returns to its original standby position. Next, the molten copper is discharged from the reservoir 4 to the weighing pan 6, and the same process as described above is carried out.

During and after the above casting operation, the casting device 12
continues to move in the direction of the arrow. Then, casting is performed in the next mold 8 by the same operation as described above.

It should be noted that although the above description is based on the operation under ideal conditions, in reality, "clogging" may occur at the outlet B of the weighing pot 6. In such a case, depending on the situation, the end position D may be a relative distance L.
Even when the position is reached, the casting of a predetermined weight of molten copper may not be completed. In that case, the casting device 12
The movement of the weighing device 7A is automatically stopped, waits for completion of casting, and restarted at the timing determined by the weighing device 7A.

Conversely, if the area through which molten copper passes increases due to deterioration of the refractories at the outlet B, casting will be completed before the end position D reaches the relative distance L. However, no particular problem occurs in subsequent operations.

As described above, the time interval required for one cyclically repeated step in the casting operation process is not constant, even when observing the time interval at which the command to start tilting the basin 4 is issued. That is, as mentioned earlier, this tilting start command is issued when the limit switch detects a fixed position on the way back to the weighing pan 6, and the outflow port B of the weighing pan 6 is detected. The repetition time interval of one step cannot be strictly constant due to the change in flow rate due to the conditions of . Therefore, it is meaningless in terms of flow rate control to adjust the tilting speed of the refining furnace so as to keep the weight of the reservoir constant at regular intervals.

Based on the above, embodiments of the present invention will now be described.

Basic adjustment of the tilting speed of the refining furnace 1 First, with reference to FIGS. 2 and 3, the relationship between the tilting angle θ of the refining furnace 1, the rotation speed N, and the flow rate Q of molten copper 2 per unit time is explained. state

In FIG. 2, a straight line V-V is a vertical line passing through the center O in the cross section of the refining furnace 1, and a straight line H-H is a horizontal line. The angle formed by the line segment connecting the outlet point A and the center point O and the vertical line V-V is defined as the tilt angle θ of the refining furnace 1. Let the flow rate of molten copper per unit time be Q, the tilting speed of the refining furnace 1 be N, and the specific gravity γ of the molten copper, the brick inner length L of the refining furnace 1, the brick inner diameter D, the width W of the outlet, etc. Assuming that K is a constant determined by the rotation speed, the tilting speed N is expressed as N=K・Q・f(θ) (1) based on these geometric relationships.

Here, f(θ) is a function of the tilt angle θ.
The relationship between the tilting angle θ and the tilting speed N is illustrated in FIG. 3. It can be seen from Figure 3 that in order to keep the flow rate Q constant, the tilt angle θ must be
The tilting speed N must be slowed down when the angle is close to 90 degrees, and increased as it approaches 0 degrees (or 180 degrees). Furthermore, as is clear from equation (1), at any tilting angle θ, the tilting speed N is directly proportional to the flow rate Q of molten copper per unit time set at that time.

Also, as shown in Figure 3, the flow rate is Q ₁ and
Tilt angles θ _a and θ _b when kept constant at Q ₂
The tilting speeds at N _1a , N _2a and N _1
b and N _2b , between them Q ₁ /Q ₂ =N _1a /N _2a =N _1b /N _2b ...
…The relationship (2) holds true. The control method of the present invention is realized by using the relationships of equations (1) and (2) above.

Next, a basic adjustment circuit for performing basic adjustment using this principle will be explained. In FIG. 1C, the Sershin receiver 27 rotates in response to the output signal from the Sershin transmitter 26 (FIG. 1b). The rotation angle of the Sershin receiver 27 is proportional to the tilt angle θ of the refining furnace 1. Therefore, the signal output from the tilt angle signal generating potentiometer (hereinafter referred to as tilt angle potentiometer) 28 connected to the Sershin receiver 27 is also proportional to the tilt angle θ. The tilt angle signal θ is input to the function generator 29. The function generator 29 generates the function f of equation (1).
A signal corresponding to (θ) is output. This output signal f(θ) is multiplied by a constant K in an operational amplifier 30, and converted into a level as a control signal for the low speed variable speed motor 22 (FIG. 1b).

In addition, in equation (1), K is treated as a constant, but in order to compensate for changes in the brick inner length L, brick inner diameter D, etc. during the operation process of the refining furnace 1, a correction circuit is used as an amplifier. 30 can be provided. By doing so, more appropriate adjustment becomes possible.

The signal output from the operational amplifier 30 corresponds to K·f(θ) in equation (1). Flow rate setting potentiometer (hereinafter referred to as flow rate potentiometer)
31 is the output signal K·f(θ) of the operational amplifier 30
This is to make the change proportional to the flow rate Q of molten copper set from the production process or the like. Therefore, depending on the setting of this potentiometer 31, the flow rate setting can be arbitrarily changed according to the plant.

In this way, in the circuit from the Sershin transmitter 26 to the flow rate potentiometer 31, the ideal basic tilting speed N=K・Q・
A basic adjustment signal V _B corresponding to f(θ) is obtained.

By the way, the discharge of molten copper from the refining furnace 1 is ideal as shown in equation (1), and the outlet A, the gutter 3, etc. do not act as disturbance elements to the flow of molten copper, and the flow of the molten copper in the sump 4 is ideal. If the measurement time period of molten copper weight is constant,
As shown in FIG. 4, the molten copper weight W _H in the reservoir 4 is always equal to the set value W _S at measurement times t ₁ and t ₂ .
In other words, the same values should be repeated like W _H1 and W _H2 .

In addition, in FIG. 4, W _H1 , W _H2 , W _Hi , W _Hi+
1 and W _Hi+2 indicate the weight of molten copper in the reservoir 4 at the time when the command to start tilting was issued to the reservoir 4, that is, at the time of measurement. At that time of measurement, Tamanenabe 4
Molten copper is continuously flowing in through the gutter 3, and this state is measured by the weighing device 5A. Therefore, as shown in FIG. 4, the weight of molten copper in the reservoir 4 continues to increase. Each top point of the graph indicates the weight at the moment when the molten copper begins to flow out, and each bottom point indicates the weight at the moment when the discharge from the reservoir pot 4 to the weighing pot 6 is completed. Although the details will be described later, the fact that the weight in the reservoir 4 at the time of measurement becomes a broken line toward the highest point with boundaries of W _Hi , W _Hi+1 , and W _Hi+2 is due to the correction adjustment of the present invention. This is because the current flow rate is changed to a new value.

Now, the refining furnace 1 is basically adjusted to an ideal tilting speed N in accordance with equation (1). However, this works effectively when the conditions of the supply device are ideal, and as mentioned earlier, during actual operation,
The flow rate of molten copper per unit time from the refining furnace 1 does not match the set value Q due to the influence of various disturbance factors. In addition, due to the influence of the condition of the refractory material of the weighing pan 6 and the condition of the outlet B, the cycle of measuring the weight of molten copper in the basin 4 is not constant. The molten copper weight W _H varies depending on the measurement period and is not constant. Therefore, it is necessary to bring the molten copper weight W _H in the reservoir 4 close to the set value W _S at each measurement period. This is the purpose of the correction circuit described below.

Correction of the molten copper weight W _H in the reservoir 4 As shown in Fig. 4, there is a certain measurement time t _i during operation.
Let W _Hi be the actual value of the weight of molten copper in the reservoir 4 at , and let W _S be the weight of molten copper set at that time, then the difference △W _i is △W _i = W _Hi - W _S ...... (3) In the case of Fig. 4, for example, △W _i is shown as a positive value, so in order to make this difference △W _i = 0 at the next measurement time, the flow rate Q must be reduced. Needs to be corrected.

By the way, during general operation, the types of products (cast products) that can be produced are limited, and the production amount is determined by weight/time or number of products/time. Therefore, the time required to cast one product is calculated backwards, and this value is hereinafter referred to as the nominal cycle time. As mentioned earlier, the actual cycle time is not constant. However, when comparing the actual cycle time and the nominal cycle time individually, they are close. Therefore, if △Q _i is the value obtained by dividing △W _i in equation (3) by the nominal cycle time CT, then △Q _i =△W _i /CT (4). This ΔQ′ _i , like Q above, represents the weight of molten copper per unit time.

Therefore, if the flow of molten copper from the refining furnace 1 to the sump 6 is not affected by disturbances and the actual cycle time is equal to the nominal cycle time, then between the measurement times t _i and t _i+1 , by correcting the basic tilting angular velocity N so as to subtract the molten copper flow rate ΔQ _i from Q, the molten copper weight in the sump 4 reaches the set value W _S after time CT from t _i , that is, at t _i+1. be equal. In reality, the flow of molten copper from the refining furnace 1 to the weighing pan 6 is not ideal due to disturbances, and the actual cycle time is not equal to the nominal cycle time. Strictly speaking, there is a difference between the measured value of the weight of molten copper in the reservoir and the set value _WS , but the difference is extremely small and good operating conditions can be obtained.

Correction of tilting speed N A method for correcting tilting speed N according to ΔQ _i in equation (4) will be described. The corrected tilting speed (hereinafter referred to as corrected tilting speed) is N', and the corrected flow rate is Q-△Q _i , so by substituting this into equation (1), N'=K・( Q-△Q _i )・f(θ) =K・Q・f(θ)−K・△Q _i・f(θ)
......(5) is obtained. The first term on the right side of equation (5) is equal to the basic rotational speed N, and if the second term is for the corrected flow rate △Q _i and the corrected tilting speed is △N _Qi , then equation (5) becomes N' It can be expressed as =K・Q・f(θ)−K・△Q _i・f(θ) =N−△N _Qi (6).

Here, the actual weight difference at measurement time t _i is △
W _i , the calculated corrected flow rate is called △Q _i , and the subscript “i” is added to the tilting angle, basic tilting speed, and corrected tilting speed, and θ _i , N _i , N′ Let it be _i . Further, the corrected tilting speed will be expressed as ΔN _Qi( 〓 _i) by adding a subscript "θ _i " to mean the value at the tilting angle θ _i .

Therefore, equation (6) is N′ _i =K・Q・f(θ _i )−K・△Q _i・f(θ _i )=N _i −△N _Qi( 〓 _i) ………(7 ) becomes.

The corrected flow rate ΔQ _i is maintained until the next measurement time t _{i +1} . On the other hand, basic tilting speed N, modified tilting speed
N' and the corrected tilting speed ΔN _Qi change as a function of the tilting angle θ. When the measurement time t _i+1 is reached, the tilting angle becomes θ _i+1 , and if each of the above values is expressed as in equation (7), N′ _i +1=K・Q・f ₍ 〓 _i+1) −K・△Q _i・f ₍ 〓 _i+1 ) =N _i+1 −△N _Qi( 〓 _i+1) ………(8).

Similarly, the next measurement is performed at measurement time ti ₊₁ , and a new measurement value W _Hi+1 , weight difference ΔW _i+1 , and corrected flow rate ΔQ _i+1 are obtained. This weight difference △W _i+
If the value of ₁ is a negative value as shown in FIG. 4, it is necessary to increase the flow rate Q until the next measurement time t _{i +2} . Taking these into consideration, and expressing it using equation (7), N' _i+1 = K・Q・f ₍ 〓 _i+1) +K・△Q _i+1・f ₍ 〓 _i+1) = N _i+1 +△N _Qi+1( 〓 _i+i) ......(9). Then, the corrected flow rate △Q _i+1 is maintained until the next measurement time t _i+2 , and at the measurement time t _i+2 N′ _i+2 =K・Q・f ₍ 〓 _i+2) +K・△Q _i+1・f ₍ 〓 _i+2) =N _i+2 +△N _Qi+1( 〓 _i+2) ......(10) is the same as equation (8) . Then, corrections are made in the same manner for the next and subsequent measurement times.
The process from equations (7) to (10) above is shown in FIG.

Next, a correction adjustment circuit for performing correction adjustment using this principle will be described.

In FIG. 1C, a molten copper weight signal W _H in the basin 4 is continuously supported at one end of the fixed contact of the contact 32 from the weighing device 5A (FIG. 1a). Also,
From the weighing device 7A (FIG. 1a), a command to start tilting the reservoir pot is given as a measurement timing signal _ti . Therefore, each time the measurement timing signal is input, the molten copper weight W _Hi at the time t _i is obtained at the other end of the contact 32.

On the other hand, a set weight W _S is set by a potentiometer (hereinafter referred to as a weight potentiometer) 33 for setting the weight of molten copper in the reservoir 4 .

The molten copper weight W _Hi and the set weight W _S are compared by a comparator 34, and as a result, the weight difference △W
_i (see equation (3)) is calculated. This ΔW _i takes a positive or negative value according to equation (3). And this weight difference△
W _i is input to the operational amplifier 35, and the amplifier 35 calculates W i according to the preset nominal cycle time CT.
Equation (4) is calculated, and as a result, the flow rate △Q _i
get.

Then, in the amplifier 36, the function generator 29
The function f(θ) is extracted from the contact point 40, and the second term on the right side of equation (6) is calculated from that value and the flow rate ΔQ _i . That is, the corrected tilting speed △N _Qi △N _Qi =K·△Q _i ·f(θ) is calculated, and as a result, a corrected signal V _R is obtained. This correction signal V _R acts to decrease or increase the set flow rate Q depending on the positive or negative sign of the weight difference ΔW _i .

The basic adjustment signal V _B and correction signal V _R obtained in this way are input to a comparator 37, and the deviation signal thereof is sent to the next comparator 39 as a modified control signal V _S.

The correction control signal V _S is the variable speed electric motor 22 for low speed.
When considered, this corresponds to a target value signal for the electric motor 22. Therefore, ideally it should rotate at a speed that corresponds to this modified control signal V _S .
Therefore, the electric motor 22 is connected to the rotary generator 24 and the amplifier 3.
A feedback loop of 8 is provided and feedback control is performed via a comparator 39.

That is, a signal nF proportional to the rotation speed of the electric motor 22 is output from the rotary generator 24 and input to the amplifier 38. The amplified signal V _F is compared with the modified control signal V _S in a comparator 39, and the deviation is applied to the motor 22 as the motor control signal V _C.

In the above embodiment, the weight W of molten copper in the reservoir 4
The measurement timing of _H may be arbitrarily set as long as the molten copper is not being discharged from the reservoir 4 to the weighing weight 6. In addition to the nominal cycle time CT, the time interval used to calculate the corrected flow rate ΔQ _i may be the time interval before one process, or the next measurement time interval predicted using a computer or the like. Regarding the corrected flow rate ΔQ _i itself, in addition to making sure that the difference between the actual value of the molten copper weight in the reservoir 4 and the set value becomes zero at the next measurement time, for example, at the 0.5th, 1st, 5th, etc.
Even if the value is set to zero after the second or third time interval, there will be few problems in actual operation. The present invention is also applicable to molten copper to be controlled, other molten metals, or liquids. Furthermore, the present invention can be applied to any shape of container or liquid as long as the relationship between the outflow amount per unit time, the tilt angle, and the speed is expressed mathematically.

As described above, according to the present invention, the tilting speed of the tilting container is continuously controlled, and moreover, it is ideally controlled by the basic adjustment and further theoretical correction adjustment is performed. Highly accurate flow rate control can be performed. As a result, fluctuations in the amount of liquid discharged can be suppressed as much as possible, making it possible to provide products with stable quality.

[Brief explanation of the drawing]

Fig. 1a is a schematic diagram showing the general configuration of a liquid material supply device including a refining furnace and a casting device, Fig. 1b is a block diagram showing a driving device of the refining furnace, and Fig. 1c is a liquid material supply according to the present invention. A block diagram showing the configuration of the flow rate control device, Fig. 2 is a longitudinal sectional view showing the relationship between the outlet in the refining furnace and its tilting angle, and Fig. 3 shows the relationship between the refining furnace's tilting angle θ and the tilting speed N. A diagram showing the relationship between
FIG. 4 is a diagram showing the relationship between the molten copper weight measurement timing t and the measured weight W _H , and FIG. 5 is a diagram showing the manner of correcting the tilting speed N. 1... Refining furnace, 4... Water pot, 6... Weighing pot, 2
2...Low speed variable speed electric motor, 26...Selsyn transmitter, 27...Selsyn receiver, 29...Function generator, 35...Operation amplifier, 37...Comparator, θ
...Tilt angle signal, f(θ)...Tilt angle function,
t _i ...measurement time, V _B ...basic adjustment signal, V _R ...
...correction signal, V _S ...correction control signal, △Q _i ...correction flow rate, W _Hi ...molten copper weight in the reservoir, W _S ...set weight, △W _i ...weight difference.

Claims (1)

[Scope of Claims] 1. A tilting container that continuously discharges a liquid material through a tilting motion, a reservoir that receives the discharged liquid matter, stores it, and discharges it every predetermined weight by a tilting motion; In a liquid supply device equipped with a weighing pot that receives liquid discharged from a pot, stores it, and discharges it to the next production process every predetermined weight, the tilting angle of the tilting container is continuously detected. The basic tilting speed control signal includes a function generator that continuously generates a corresponding tilting speed signal to keep the amount of liquid flowing out from the tilting container constant based on the tilting angle signal obtained from the tilting angle signal. and a basic adjustment circuit that outputs a deviation value between the weight of the liquid in the reservoir and the set reference weight at a certain measurement time set during a period in which no liquid is discharged from the reservoir to the weighing pan. a correction adjustment circuit that outputs a correction signal that converts the basic tilting speed control signal into a value per one process operation time of the pot and corrects the basic tilting speed control signal based on the converted value and the tilting speed signal; A liquid material supply flow rate control device comprising: a comparator for outputting a rotational speed control signal to a tilting container drive device based on a speed control signal and a correction signal.