JPH0811287B2 - Electromagnetic pouring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to the temperature of a heater when the molten metal accumulated in a container (for example, an expensive molten metal containing iron as a main component and an expensive additive is added) is used. The present invention relates to an electromagnetic pouring device that supplies a fixed amount by the action of an electromagnetic pump that extends obliquely upward from the bottom portion on the container side under compensation for deterioration.

[Prior Art] Generally, the basic configuration except the control unit of the electromagnetic pouring device is the second
The configuration is as shown in the figure. In FIG. 2, 1
Is a molten metal container, which holds the molten metal 2 supplied from the outside, and keeps the temperature of the molten metal 2 constant by an induction heater 3 arranged at the bottom of the container 2 (this action is performed by the molten metal in the container). This can be achieved by known means for controlling the energization time of the heater 3 so that the surface temperature of 2 becomes constant). Reference numeral 4 denotes an electromagnetic pump, which comprises a refractory tube 4a for guiding the molten metal 2 obliquely upward from the side bottom of the molten metal container 1 and an inductor 4b for providing thrust to the molten metal 2 in the refractory tube 4a obliquely upward.

In the above configuration, a fixed amount of molten metal is supplied within a range up to a configuration (a region L / 3 below the length L relative to the length L of the dielectric 4b) in which the suction force is reduced due to the vertical end effect of the electromagnetic pump inductor 4b. The molten metal 2 was replenished to the container 1 for constant quantity supply.

[Problems to be Solved by the Invention] In the above-mentioned conventional fixed amount of molten metal supply, even though there is no problem in the process of repeatedly supplying and pouring molten metal, the amount of remaining molten metal reaches a considerable amount, and for example, operation is stopped at night. At the time of keeping the temperature of the residual hot water, a considerable amount of electric power is required and the number of times of replenishment of the molten metal is increased, resulting in a decrease in work efficiency.

[Means for Solving Problems] The gist of the present invention is a control means for continuing the constant supply of the molten metal from the molten metal container to the end effect generation region of the electromagnetic pump inductor.

[Operation] The increase rate of the power supply amount is increased to compensate for the thrust decrease corresponding to the end effect from the time when the molten metal held in the container decreases to the end effect generation region of the electromagnetic pump inductor.

[Embodiment] The control circuit shown in FIG. 1 will be specifically described below. In FIG. 1, 11 is a potentiometer, which is a container 1
Output according to the molten metal level inside (the output is small when the molten metal level is high, and increases as the molten metal level decreases)
Supply. Reference numeral 12 is an amplifier, the amplification degree of which changes depending on the resistance value connected to the input / output side. Reference numeral 13 denotes a power control circuit, which controls the power supplied by the input from the amplifier 12 (phase control of the thyristor) and supplies the power to the inductor 4b. Reference numerals 14 and 15 denote comparators, which receive inputs from the potentiometer 11 respectively. For example, at inputs 0 to 5V, the comparator 14 is inverted at 3V, and the comparator 15 is
Set to invert at 4V (set to generate the edge effect of the electromagnetic pump inductor 4b at 3V input). The relays 16 and 17 are excited by the outputs from the comparators 14 and 15, respectively. R ₁ , R ₂ , R ₃ , and R ₄ are resistors, 16a is an A contact of the relay 16, 16b is a B contact of the relay 16, 17a is an A contact of the relay 17,
17b ₁ and 17b ₂ are B contacts of the relay 17, which are connected as shown in the drawing.

The operation of the above-described structure will be described with reference to FIG. 3 (a relationship diagram between the molten metal level L in the container and the electric power W supplied to the electromagnetic pump). First, in a state where the molten metal 2 is fully filled in the container 1 (molten metal level L ₀ ), the output of the potentiometer 11 is very small and the amplifier 12 is determined by the resistors R ₁ and R _2. The power supply circuit 13 is controlled by the amplification factor (supplied power W ₀ to the electromagnetic pump at this time), and pouring is started from the electromagnetic pump 4. In this process, as the molten metal level in the container 1 decreases, the output of the potentiometer 11 correspondingly increases. Along with this, by increasing the conduction time of the thyristor in the power supply circuit 13, the power to the electromagnetic pump inductor 4b is increased at a substantially constant amplification factor.

Now, in the pouring process, when the molten metal level in the container 1 reaches L ₁ , the output of the potentiometer 11 increases to 3V (from this time, the thrust of the electromagnetic pump decreases due to the end effect), and the input to the electromagnetic pump W ₁ Then, the output from the comparator 14 is obtained. Along with this, the relay 16 operates and the A contact 16a of the relay 16 is closed, and at the same time, the B contact 16b is opened. Therefore, the amplification factor of the amplifier 12 is determined by the resistors R ₁ and R ₃ (the amplification factor is larger than before) and the coil of the electromagnetic pump 4 is amplified.
The input to 4b is increased and the thrust of the electromagnetic pump 4 is increased.

Further, the level of the molten metal 2 in the container 1 is lowered to L ₂ and the output of the potentiometer 11 is increased to 4 V, so that the electromagnetic pump 4
When the input to the relay reaches W ₂ kW, the output from the comparator 15 is obtained in addition to the comparator 14, and the B contact 17 of the relay 17
b ₁ and 17b ₂ are opened, and A contact 17a is closed. As a result, the amplification factor of the amplifier 12 is regulated by the resistors R ₁ and R ₄ , and the increase rate of the power supplied to the electromagnetic pump 4 relative to the constant reduction rate of the molten metal level is increased.

It should be noted that in the above embodiment, since the molten metal level in the container causes the thrust to decrease due to the end effect of the electromagnetic pump 4, the electromagnetic pump is connected to the electromagnetic pump in two stages when the power supply amount is increased for the purpose of increasing the thrust. Although the example in which there is a change in the increase rate of the supply power of is shown, in the fixed amount supply of the molten metal regardless of the accuracy of the fixed amount supply, one-stage control may be used.
In particular, when high accuracy is required, the characteristics of three or more steps may be given.

[Effect] As described above, in the electromagnetic pouring device according to the present invention, when performing fixed quantity pouring per unit time by the electromagnetic pump extending obliquely upward from the bottom of the container side, the same ratio is obtained due to the end effect of the electromagnetic pump. When the region where the thrust is reduced by increasing the power supply is reached, the increase rate of the power supply is changed to one or a plurality of stages in order to compensate for the thrust decrease of the electromagnetic pump due to the end effect. Based on this configuration, when the molten metal is supplied in a fixed amount, the amount of the residual molten metal in the container can be remarkably reduced, and it is possible to reduce the loss due to the discard of the residual molten metal or the energy for keeping the expensive molten metal.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a sectional view of an apparatus for carrying out the present invention, and FIG. 3 is a graph for explaining the operation. 1 …… Molten container 2 …… Molten metal 3 …… Induction heater 4 …… Electromagnetic pump 11 …… Potentiometer 12 …… Amplifier 14, 15 …… Comparator 16, 17 …… Relay

Claims (1)

[Claims] 1. An electromagnetic pouring device (A) a molten metal container (B) having the following items: an induction heater for maintaining the temperature of the molten metal contained in the molten metal container (C) a bottom portion of the molten metal container Electromagnetic pump that is arranged more obliquely upward and is responsible for the constant supply of molten metal (D) Inversely proportional to the level of molten metal until it reaches a region where thrust is reduced due to the end effect of the lower part of the electromagnetic pump. Power supply control means for the electromagnetic pump, which supplies a fixed amount of power to increase the power supply increase rate to one or a plurality of steps within a range where molten metal can be supplied from the region where the thrust is reduced.