JPS6147625B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for automatically pouring molten metal into a mold.

In conventional automatic pouring, methods for determining or detecting the completion of pouring, that is, when the mold is full of molten metal, include measuring changes in the weight of the mold or ladle;
Alternatively, a well-known method is to provide a separate hole in the mold in addition to the sprue and detect it with a phototube.

The major disadvantages of the above-mentioned weight measurement method are that the equipment is expensive and that the detection accuracy is insufficient due to the weight of the ladle or mold.

The method of detecting mold lift has drawbacks such as tedious molding work and decreased pouring yield. In the actual pouring process, if the determination of fullness is too late, the molten metal may spill, which is dangerous, and if the determination is made too early, there will be insufficient pouring, or what is commonly called drying, resulting in products with poor hot water performance.

The present invention automatically controls the pouring of molten metal into a mold by using the level of the molten metal in the mold sump and a predetermined period of time including the scheduled completion time of pouring as control elements. It is an attempt to improve the shortcomings of technology.

The present invention will be explained below based on examples.

FIG. 1 is an example of an apparatus for carrying out the present invention. In the figure, 1 is a mold reservoir, 2 is a ladle, 3 is a ladle tilting cylinder, 4 is an electromagnetic flow control valve that controls the ladle tilting cylinder 3, and 5 is a control circuit that determines the pouring speed pattern. It is a control device consisting of. A detector 6 detects the level of molten metal in the sump 1 of the mold. As this detector 6, a two-dimensional sensor can be used.

Fig. 2 shows that a two-dimensional sensor is used in the detector 6 of Fig. 1 to form an image of the mold sump within the detection field of view 10 of the detector 6 from directly above or diagonally above the sump. The detection state is shown divided into a bright area consisting of the flow 7 of hot water from the pot and the molten metal 8, and a dark area consisting of the other area 9. In the figure, a shows a state immediately after the start of pouring, b shows a state controlled to maintain the reference level I in FIG. 3 during pouring, and c shows a state in which the molten metal 8 exceeds the reference level A and fills the mold. In this manner, the detector 6 of FIG. 1 detects the level of molten metal in the mold sump.

Next, the pouring control method of the present invention will be explained.

FIG. 4 shows an example of a pouring speed pattern for a certain type of mold when pouring control according to the present invention is performed. T ₀ is a period during which molten metal starts to be dispensed from the ladle 2, and the ladle is tilted at a high speed of V ₀ . During period T ₁ after the start of tapping, control is performed at medium tilting speeds of V ₁ and V ₂ in order to quickly fill the mold reservoir with hot water.
A indicates that the molten metal has reached the standard level (A in Figure 3) that should be maintained in the sump of the mold.
During the T ₂ period, there are multiple stages, e.g. t ₁ to t ₅ .
It is divided into stages and rotated at a tilting speed of V ₃ to _{V 7} . B
is the expected filling point at which the mold completes the teacup.
V ₃ to _{V 7} are predetermined at appropriate speeds to maintain the hot water level at a constant level (reference level A) under normal conditions. During the _T3 period, reverse tilting is performed at a tilting speed of _V8 to drain the hot water, completing one cycle of pouring work.

The ladle tilting speeds V ₀ to V ₇ shown in FIG. 4 are gradually decreased. This is to correspond to the pouring speed of the molten metal in the mold, and represents an ideal pouring speed pattern.

The present invention controls the pouring of metal into the mold by detecting the fullness of the mold during period _t5 of the above-mentioned pouring cycle. This control method will be explained with reference to FIG.

FIG. 5 shows an embodiment of a logic circuit for detecting fullness. Input conditions 11 to 14 correspond to hours t ₁ to t ₄ in FIG. 4, and if the pouring process occurs during any of these hours, input conditions 1
It becomes one. 15 is one of the input conditions when the detector detects that the molten metal level in the mold sump shown in FIG. 3 is at the overflow level H. 16
17 is the input condition that the pouring process is in period _t5 in Figure 4, and 17 is the input condition when the detector detects that the molten metal level in the mold reservoir is at the upper limit level RO shown in Figure 3. This is one thing. 18 is input condition 11
- OR circuit where the output turns ON when any one of 14 is satisfied, 19 is OR with input condition 15
AND circuit whose output turns ON after both input conditions from circuit 18 are met; 20 is input condition 16 and 1;
21 is a delay circuit whose output is turned ON after the input from the AND circuit 19 is held for a certain period of time, and 22 is a delay circuit whose output is turned ON after the input from the AND circuit 20 is held for a certain period of time. 23 is an OR circuit whose output turns ON when the input condition of either delay circuit 21 or 22 is satisfied.
4 is an amplifier, 25 is an arithmetic circuit, 26 is a control valve 4 shown in FIG. 1, 27 is a tilting cylinder 3 shown in FIG. 1, and 28 is a hydraulic power source.

The input condition 16,1 is determined by the logic circuit explained above.
7 is established, and the delay circuit 22 holds the output for a certain period of time, and then the AND circuit 23 turns on the output, that is, it is determined that the ladle is full, and the ladle tilting cylinder 27 is operated by the control valve 26 via the amplifier 24 and the arithmetic circuit 25. Tilt the ladle in the opposite direction to stop pouring.

The present invention described above has the following effects.

(1) During pouring, the level of the hot water in the reservoir may jump from time to time, and there is a risk that detection based only on the level of hot water may lead to the conclusion that the tank is full when it is actually not. On the other hand, under normally managed or controlled working conditions, the time required for pouring does not vary greatly. In the present invention, as mentioned above, the determination of fullness is based on three factors: the time factor, the hot water level itself, and the fact that the teacup is no longer filled even though pouring has been temporarily stopped. , the above-mentioned errors in judgment are almost eliminated.

(2) By making a judgment based on the level B below the hot water level, rather than the level on the verge of spilling, as in the hot water level C in Figure 3, there is the effect of reducing the amount of hot water spilling and saving hot water.

(3) In actual work, if a part of the mold breaks, that part may be crushed. In this case, the pouring time will be significantly shorter than the standard pouring time, so it will not fit within the set time period. In the present invention, only in such a case, when the level is on the verge of spilling, that is, input condition 15 is satisfied, and the delay circuit 21 determines that the water is full after holding the water for a certain period of time, and stops pouring.

In addition, in the present invention, the period _t5 in Fig. 4, which includes the scheduled time until filling, is a normal state, that is, the period t5 until filling takes into account various factors such as slight variations in molding, errors in tilting speed, and changes in hot water temperature. Needless to say, the time zone must be such that deviations from the scheduled time can be tolerated. In addition to the step-by-step programmed pouring method as described in the embodiment until period _t4 in FIG. Needless to say, this method can be easily applied to other systems.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an apparatus for carrying out the present invention, and Fig. 2 is a diagram showing the state in which the molten metal level in the mold sump is detected by the detector shown in Fig. 1, and a is immediately after the start of pouring. , b shows the state in the middle of pouring, and c shows the state filled with molten metal. Figure 3 shows the level of the molten metal in the mold sump of Figure 1. Figure 4 shows the mold pouring speed pattern. , FIG. 5 is an example of a logic circuit of the control method of the present invention. 1: Water reservoir, 2: Ladle, 5: Control device, 6: Detector.

Claims (1)

[Scope of Claims] 1. A control method for pouring molten metal into a mold by detecting the level of the molten metal in the mold sump with a detector and tilting the ladle, from the start of pouring to the completion of pouring. The time period is divided into a plurality of time periods, a pattern of the time periods and the tilting speed of the ladle is registered in advance in the control device, and the control device controls the tilting speed of the ladle based on the pattern. The pouring time is within the expected full time period of the time period, and the level of the hot water in the mold sump as detected by the detector rises above a predetermined limit, and the pouring time is within the scheduled full time period of the time period, and A molten metal pouring control method characterized in that molten metal pouring is completed when the above-mentioned conditions are satisfied.