JPH089095B2 - Controller for automatic pouring furnace - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic pouring furnace which pressurizes the inside of the furnace and discharges the molten metal stored in the furnace from the pouring port, and particularly detects wear of the pouring port. The present invention relates to a control device for an automatic pouring furnace.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional pressurized pouring furnace 1. In FIG. 3, reference numeral 2 is a hot water storage chamber in which the molten metal 3 is stored. A pouring chamber 4 is provided with a pouring port 5 for discharging the molten metal 3 at a predetermined portion of the pouring chamber 4. Reference numeral 6 denotes a pressure pipe for applying a pressure to the molten metal 3 in the hot water storage chamber 2 and is connected to a pressure adjusting device (not shown). Reference numeral 7 denotes a hot water inlet for supplying molten metal to the pouring furnace 1. During standby, a predetermined base pressure is applied to the molten metal 3 in the hot water storage chamber 2.

FIG. 4 shows the pouring of the pouring furnace 1 shown in FIG. By applying a predetermined pressure (shot pressure) to the molten metal 3 in the hot water storage chamber 2 from the pressure adjusting device and pushing down the molten metal level in the hot water storage chamber 2, the molten metal level in the molten metal pouring chamber 4 is pushed up, and Molten metal 3 is poured from a mold 5 (not shown) located below.

The pouring amount Q at this time is expressed by the following formula 1 where H is the molten metal level in the pouring chamber 4, S is the opening area of the pouring port 5, and T is the shot pressure application time.

[0005]

## EQU1 ## Q = k.S (2g.H) ¹ / 2.T where k is a proportional constant and g is a gravitational constant. As can be seen from this equation, the molten metal level H, that is, the shot pressure and the shot pressure application time T were controlled in order to discharge a certain amount of molten metal.

[0006]

However, if the pouring port 5 wears more than a predetermined amount and its diameter increases, and the opening area S of the pouring port 5 increases, the pouring amount Q also increases, so that automatic pouring is performed. I can't do hot water. Therefore, it is necessary to accurately grasp the wear amount of the pouring port and replace the part of the pouring port 5 before the pouring amount changes significantly.

Conventionally, the pouring port 5 has been replaced at a replacement cycle known from experience, such as the number of pouring frames or every week.

[0008] Therefore, an object of the present invention is to provide a control device for an automatic pouring furnace capable of knowing an optimum pouring opening replacement period while maintaining pouring accuracy.

[0009]

According to the present invention, such an object is to detect the amount of wear at the pouring port,
Based on the furnace body weight measuring instrument installed in the lower part of the furnace body and measuring the weight of the furnace body, and the output signal of this furnace body weight measuring machine, the weight of the past n times of pouring for each pouring as the moving average pouring amount Pouring amount calculation means for calculating changes w ₀ , w ₁ , w ₂ ...
By providing a wear amount calculation means for calculating the wear amount of the pouring port by comparing the initial average value w ₀ by the first n times of pouring with each subsequent average value w ₁ , w ₂ ... To be achieved.

[0010]

According to the present invention, the weight of the furnace body is measured by the furnace body weight measuring device provided in the lower part of the furnace body, and the moving average pouring amount is calculated from the output signal of the furnace body weight measuring device by the pouring amount calculation means. For each pouring, the weight changes w ₀ , w ₁ , w _2, ... Due to the past n times of pouring are calculated, and the wear amount calculating means calculates the initial average value of the first n times of pouring. The wear amount of the pouring spout is calculated by comparing w ₀ with each subsequent average value w ₁ , w _2, ...

[0011]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a control device according to the present invention. In FIG. 1, reference numeral 10 is a load cell for measuring the weight of the pressure pouring furnace 1. Reference numeral 11 is a molten metal weight detector for calculating the weight W _i (i = 0 to n) of only the molten metal 3 after each pouring by subtracting the tare weight of the furnace body from the weight of the furnace body obtained by this load cell. ₀ indicates the weight of the molten metal before pouring. Reference numeral 12 is a memory circuit for storing each molten metal weight W _i obtained by the molten metal weight detector 11. Reference numeral 13 is an arithmetic circuit for sequentially calculating an average pouring amount w _i over n times of pouring from the respective molten metal weights W _i stored in the memory circuit 12, as shown in Formula 2.

[0013]

[Number 2] _{w 0 = (W 0 -W n} ) / n w 1 = (W 1 -W n + 1) / n w 2 = (W 2 -W n + 2) / n w 3 = (W 3 −W _{n + 3} ) / n ··· w _i = (W _i −W _{n + i} ) / n

In this way, the reason why the average value over n times is adopted is that the load cell 10 detects the tare weight of the furnace near several tens of tons, and the weight reduction amount that decreases with each pouring amount is detected. Is difficult in terms of accuracy. The average pouring amount is calculated once from the weight difference after pouring after n times. By setting the value of n to about 20 to 30, it is possible to eliminate variations in the detected weight and obtain highly reliable data. In this embodiment, 20 is adopted as the value of n.

In reference numerals 14 and 15, w ₀ is used as an initial value based on the weight of the average pouring amount obtained from the arithmetic circuit 13, and this initial value w _{0 is used.}
And first and second determination circuits for comparing the magnitude of each weight after w ₁ . When the pouring weight w _i exceeds k ₁ · w ₀ , the first determination circuit 14 outputs a replacement command signal for notifying the replacement cycle of the pouring port 5. When the pouring weight w _i exceeds k ₂ · w ₀ (k ₂ <k ₁ ), the pressure adjusting device 16 for controlling the pressure applied from the second judging circuit 15 to the pouring furnace 1 is sent. The correction signal is output.

Next, the control operation of the above apparatus will be described. First, the weight of the pouring furnace 1 before pouring is measured by the load cell 10, and by the molten metal weight detector 11, the pouring furnace 1
The pre-measured tare weight of only the pouring furnace 1 is subtracted from the weight to obtain the molten metal weight W ₀ before pouring. This weight W ₀ is stored in the memory circuit 12. Next, when the first pouring is completed by the pressurization by the pressure adjusting device 16, the weight W ₁ of the molten metal is determined again by the load cell 10 and the molten metal weight detector 11, and is stored in the memory circuit 12. Thereafter, in the same manner, when the molten metal weight W _{20 is} sequentially measured and stored, the arithmetic circuit 13 calculates the initial average pouring amount w ₀ by the calculation of (W ₀ −W ₂₀ ) / 20, and the initial average is calculated. The pouring amount w ₀ is sent to the first and second determination circuits 14 and 15. Next, when the load cell 10, the molten metal weight detector 11, and the memory circuit 12 measure and store the molten metal weight W ₂₁ after the _21st pouring, the arithmetic circuit 13 calculates the average molten metal amount w ₁ as (W ₁ − W ₂₁ ) /
The average molten metal amount w ₁ obtained by the calculation of 20 is the first
And to the second decision circuits 14 and 15.

In the first judgment circuit 14, the average molten metal amount w ₁
Is larger than a value obtained by multiplying the initial average molten metal amount w ₀ by a constant k _1, and if it is not larger, then the second determination circuit determines that the average molten metal amount w ₁ is the initial average molten metal. It is determined whether or not the value obtained by multiplying the amount w ₀ by a constant k ₂ is exceeded, and if it is not exceeded, the wear amount of the pouring port 5 is within an allowable limit and the molten metal amount is within a range in which automatic pouring can be performed. It is determined that there is, nothing is output from the second determination circuit 15, and the 22nd pouring is continuously performed. In the same manner, the average molten metal amount w _{2 and} thereafter are sequentially obtained, and each time, the determination is made by the first and second determination circuits 14 and 15.

FIG. 2 is a graph for making the following control operation easy to understand, and shows the relationship between the opening area S of the pouring port 5 and the pouring amount Q with respect to the number of pouring frames. The number of possible pouring frames is until the pouring amount reaches the automatic pouring limit point Q _2, and in the case of the conventional control method that does not perform any correction control for the wear of the pouring port 5, it is shown in the graph of FIG. It is assumed that the number is 1000. In the embodiment of the present invention, the pouring amount Q
There when it is to Q ₁ automatic pouring limit point Q ₂ vicinity Note when the water frame number became 800 or so, the second decision circuit 15
The value of the proportional constant k ₂ is set so that the correction signal is output from the. That is, the correction output signal is output by the second determination circuit 15 before and after the signal of the average molten metal amount w ₈₀₀ is output. Once this correction signal is input, the shot pressure by the pressure adjusting device 16 is reduced by a predetermined amount, as shown in FIG.
The level H of the molten metal in the pouring chamber 4 shown in FIG. 3 decreases, and the pouring amount Q returns to the initial pouring amount Q ₀ .

After that, the opening area S of the pouring port 5 also increases, and along with this, the pouring amount Q also increases. The number of pouring frames is 1
When the number of molten metal reaches nearly 600, the pouring amount reaches Q ₁ , so that the correction signal is sent from the second determination circuit 15 again.
However, since the pressure adjusting device 16 holds the correction signal input last time, the pressure applied by the pressure adjusting device does not change. Further, when the pouring amount Q reaches the limit point Q ₂ due to wear of the pouring port 5, or when the number of pouring frames reaches about 1800, the first determination circuit 14 sends a replacement instruction signal for the pouring port 5. The value of the proportional constant k ₁ is set so as to be output. With such control, it is possible to increase the total number of pourable frames of 1000 without control to 1800, which is about double.

In this embodiment, the pouring amount is controlled by the signal from the second judging circuit 15. However, only the first judging circuit is provided and the alarm for notifying the wear of the pouring port 5 is simply provided. You may make it output a signal.

[0021]

According to the present invention, it is possible to accurately know the replacement time of the pouring spout, and it is possible to use the pouring spout until the end of its service life. Further, if the amount of hot water discharged is controlled based on the detection of wear, it is possible to discharge a fixed amount of water, so that automatic pouring is possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an operation diagram showing a control operation in the apparatus shown in FIG.

FIG. 3 is a schematic view showing a conventional automatic pouring furnace.

FIG. 4 is a schematic view showing the automatic pouring furnace shown in FIG. 3 during pouring.

[Explanation of symbols]

 1 Pouring Furnace 3 Molten Metal 5 Pouring Port 6 Pressure Tube 10 Load Cell 11 Molten Metal Weight Detector 12 Memory Circuit 13 Arithmetic Circuit 14 First Judgment Circuit 15 Second Judgment Circuit 16 Pressure Regulator

Claims (1)

[Claims] 1. A controller for an automatic pouring furnace which pressurizes the inside of the furnace to discharge molten metal stored in the furnace from a pouring port, which is provided at a lower part of the furnace body in order to detect a wear amount at the pouring port. Based on the furnace body weight measuring device for measuring the weight of the furnace body and the output signal of the furnace body weight measuring device, the weight change w ₀ due to the past n times of pouring for each pouring as the moving average pouring amount,
By comparing the pouring amount calculation means for calculating w ₁ , w ₂ ... With the initial average value w ₀ by the first n times of pouring and each subsequent average value w ₁ , w _2, ... An automatic pouring furnace control device comprising: a wear amount calculating means for calculating the wear amount of the sprue.