JPS5921264B2 - Molten metal check control device for electromagnetic pump automatic pouring machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a molten metal check control device for an electromagnetic pump type automatic pouring machine that prevents the molten metal from flowing out by applying a thrust toward the container when the molten metal is not being poured.

Generally, devices are known that supply check power in the direction of the container to an electromagnetic pump to stop the pouring of molten metal, weaken this check power, or actively apply molten metal supply power to perform pouring.

An example of this will be described with reference to FIG. 1. Reference numeral 1 denotes a container in which molten metal 2 (hereinafter referred to as molten metal) is accumulated.

Reference numeral 3 designates an electromagnetic pump, which includes a moving magnetic field generating coil 3c and a coil 3c housing which generate a thrust force in the direction of the container 1 or the opposite direction to the fireproof wall 3b forming the molten metal introduction hole 3a and the molten metal 2 existing in the molten metal 2 existing in the molten metal introduction hole 3a. It consists of a steel core 3d.

In this electromagnetic pump 3, one end of the molten metal introducing hole 3a is connected to the container 1.
The molten metal outlet 1a is connected to the molten metal outlet 1a, and an orifice 3e is provided at the molten metal pouring port on the side opposite to the container of the molten metal guide hole 3a.

In the configuration of this electromagnetic pouring machine, when supplying a fixed amount of molten metal to the external mold, for example, up to the maximum molten metal level H of container 1, the thrust force is applied 10 times more than the container.

I-Eyo L/<yvl)'s-Ka, U□. The thrust force is varied in accordance with the molten metal level in the direction of each of the 14-bracket containers, and the amount of poured metal per unit time is kept constant.

However, when the melt is not being poured, a constant electric power is supplied to the coil 3c in order to give the electromagnetic pump 3 the maximum thrust in the direction of the container 1.

Therefore, the amount of molten metal present in the molten metal introducing hole 3a of the electromagnetic pump 3 is regulated by the balance between the thrust of the electromagnetic pump 3 and the static pressure of the molten metal 2 in the container 1.
It changes depending on the level.

That is, the distance from the tip of the molten metal guided into the molten metal introducing hole 3a to the pouring port where the orifice 3e exists changes depending on the molten metal level in the container 1.

Such a change in the amount of molten metal in the molten metal introduction hole 3a increases as the time from the time when each molten pouring start command is supplied until the time when molten metal pouring is actually started decreases as the molten metal level in the container decreases.

Therefore, when issuing a constant-time fixed-time supply control command, the actual pouring time changes (decreases as the molten metal level in the container decreases), so molds of the same shape that are continuously sent are If molten metal is poured, the amount of molten metal poured into each mold will not be constant.

Conventionally, it has been difficult to compensate for this discrepancy in pouring amount.

On the other hand, in the conventional check control of the electromagnetic pump 3, the maximum thrust is applied regardless of the molten metal level in the container 1, so an unnecessary large amount of power is supplied to the electromagnetic pump especially when the molten metal level is low. This tends to result in large power losses.

The purpose of the present invention is to automatically control the check force of an electromagnetic pump type pouring machine so that the amount of molten metal entering the electromagnetic pump molten metal hole remains constant regardless of the level of molten metal in the container, thereby making effective use of electric power. In addition, the time required for molten metal to actually come out from the tip of the electromagnetic pump at the start of pouring is made constant, thereby improving the accuracy of quantitatively supplying molten metal.

The illustrated embodiment will be specifically described below.

FIG. 2 is a specific circuit diagram embodying the present invention, and the components of the electromagnetic pump type water pouring machine shown in FIG. 1 are designated by the same reference numerals.

In the figure, numeral 4 denotes a load cell that measures the weight of the container 1, the molten metal 2 contained therein, and the electromagnetic pump 3, and supplies a command according to the weight.

Reference numeral 5 denotes a static reversible voltage regulator that supplies power to the electromagnetic pump 3 in accordance with various commands to be described later.

Reference numeral 1 designates a function generator for setting the flow rate, which obtains the output signals of the load cells 4 and changes the output signal level of the polarity shown in the figure according to the signal level, thereby supplying the molten metal 2 in a fixed quantity. ing.

The output terminal of this flow rate setting function generator 7 is connected to a fixed contact 8b of a changeover switch 8.

Reference numeral 9 denotes a function generator for setting a check voltage, and the output signal of the load cell is supplied to the input side of the function generator. It is assumed that the output signal pattern for the input signal is determined by the illustrated polarity so as to keep the amount of molten metal contained in the molten metal constant.

The output terminal of this function generator 9 is connected to the fixed contact 8c of the changeover switch 8.

10 is a forward/reverse phase regulator, and a movable contact 8a of the changeover switch 8
Specifically, a signal compared with the output signal of the function generator 7 or the function generator 9 in the illustrated polarity is supplied to the input side of the absolute value circuit 11 and the positive/negative phase determination circuit 12 through the circuit.

At this time, it is desirable to switch the direction of thrust generation during pouring when the molten metal level in the container 1 is around the maximum level.

The output of the absolute value circuit 11 controls the phase of the control element in the reversible voltage regulator 5 to adjust the voltage applied to the electromagnetic pump 3, and the output of the positive/negative phase determination circuit 12 controls the moving magnetic field applied to the electromagnetic pump 3. The direction is regulated.

In the above configuration, first, when supplying the molten metal 2 in the container 1 in a fixed amount by controlling the thrust of the electromagnetic pump 3, that is, adjusting the voltage of the reversible voltage regulator 5, the movable contact 8a of the changeover switch 8 is replaced with the fixed contact 8b. , and the forward/reverse phase adjuster 10 is set so that the forward/reverse phase determination circuit 12 issues a reversal command when the molten metal level in the container 1 is at a level corresponding to half of the maximum level.

When power is supplied to the electromagnetic pump 3 with the molten metal in the container 1 at the maximum level in this manner, the output of the function generator 7 initially shows the minimum value in the ten polarities shown.

That is, the load cell 4 outputs the maximum output, the output absolute value of the function generator 7 shows the minimum, and the output of the positive/negative phase adjuster 10 is superior. As a result, the positive/negative phase determination circuit issues a negative phase command and the absolute Value circuit 11 issues a maximum command.

As a result, the electromagnetic pump 3 generates a large thrust in the direction of the container and pours the molten metal by the static pressure of the molten metal in the container.

Afterwards, as the molten metal in the container decreases, the load cell 4
As the output of the function generator 7 decreases, the output signal of the function generator 7 increases, so the output of the absolute value circuit 11 also decreases.
As a result, the voltage supplied to the electromagnetic pump 3 also decreases, and as the molten metal level decreases, the check thrust of the electromagnetic pump 3 in the direction of the container is weakened, and the difference between the molten metal pressure and the check force remains constant and constant supply is achieved.

If the molten metal in the container 1 is reduced by half due to repeated pouring, etc., the absolute values of the output level of the function generator 7 and the output level from the positive/negative phase regulator 10 become equal, and in principle, the absolute value circuit 11 Kamo's output disappears, and the electromagnetic pump 3 is no longer supplied with electric power, and the molten metal is poured only by the static pressure of the molten metal.

When pouring is carried out further, the output of the load cell 4 is further weakened, the output of the function generator 7 is further increased, and the thrust direction of the electromagnetic pump 3 is reversed in the opposite direction to the container due to the action of the forward/reverse phase determination circuit 120. The thrust is added to the static pressure of the molten metal 2 to compensate for the decrease in static pressure and continue constant supply.

The above describes the state in which the movable contact 8a of the changeover switch 8 is connected to the fixed contact 8b in order to supply a fixed amount of molten metal with the electromagnetic pump 3. It is therefore necessary to provide a non-pouring time for the next pouring.

The operation during non-pouring will be described next. That is, the movable contact 8a of the changeover switch 8 is connected to the fixed contact 8C.

Therefore, when the molten metal level in the container 1 is maximum, the output of the load cell 4 is also maximum, and the output of the function generator 9 for setting the check voltage has the highest absolute value with the polarity shown in the figure. With the action of the value circuit 110, a check force in the direction of the container is applied at maximum thrust to overcome the static pressure of the high molten metal level and reliably prevent the molten metal from flowing out.

Next, as the molten metal level in the container 1 decreases by repeating pouring and non-pouring, the output of the load cell 4 also decreases, so the output of the function generator 9 for setting the check voltage is as shown in the figure. The absolute value decreases with polarity.

Therefore, the output of the absolute value circuit 11 decreases, and the check thrust of the electromagnetic pump 3 decreases.

Since the function generator 9 for setting the check voltage is set so that the degree of decrease in the check thrust is balanced with the decrease in the thrust force for moving the molten metal out due to the decrease in the molten metal level, the level of the introduced metal in the container 1 ends up being set. Even if the amount changes, the amount of molten metal that enters the molten metal introduction hole 3a of the electromagnetic pump 3 from the container during non-pouring can be kept almost constant.

Although the above embodiment shows an example in which the molten metal level in the container 1 is detected by a load cell, the molten metal level detection means is not limited to this load cell. For example, an electrode that follows the surface of the molten metal in the container may be used. Can be replaced.

Furthermore, when pouring molten metal, the thrust direction of the electromagnetic pump 3 is not limited to the above-mentioned embodiment in which the direction of the thrust of the electromagnetic pump is reversed before and after half of the maximum molten metal level in the container, but it is possible to pour the molten metal so that the thrust of the electromagnetic pump 3 is always directed toward the container. This can also be implemented as check control for stopping pouring in hot water control.

As described above, the molten metal check control device in the electromagnetic pump type automatic pouring machine according to the present invention detects the molten metal level in the container, and the molten metal flows outside due to the static pressure caused by the decrease in the molten metal level. The check voltage setting function generator 9 is set so that the change in the static pressure of the electromagnetic pump is compensated for by the change in the check force of the electromagnetic pump.

Based on this configuration, the overall power consumption is significantly reduced compared to the conventional case where the maximum check power is applied to the electromagnetic pump 3 during non-pouring, regardless of the level of molten metal in the container. can be reduced.

The main feature of the present invention is that the amount of molten metal that enters the electromagnetic pump at the start of pouring remains constant regardless of the molten metal level in the container, so when pouring, the electromagnetic pump The time required for molten metal to start coming out from the tip is always maintained constant.

As a result, there is no room for errors in quantitative supply, and the amount of poured metal after a certain period of time has elapsed from the start of pouring control can be maintained at a constant level to ensure constant constant supply.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electromagnetic pump type automatic pouring device embodying the present invention, and FIG. 2 is a control circuit diagram according to the present invention. 1... Container, 2... Molten metal, 3...
... Electromagnetic pump, 3a ... Electromagnetic pump inlet, 4 ... Load cell, 9 ... Function generator for setting check voltage.

Claims (1)

[Claims] 1 An electromagnetic pump type automatic pourer that automatically pours molten metal stored in a container by the action of an electromagnetic pump, and when not pouring, prevents the molten metal from flowing outside based on the check force of the electromagnetic pump. The hot water machine is equipped with a means for detecting the level of molten metal in the container, and receives a signal from the molten metal level detecting means when not pouring, and sends the electromagnetic pump to a static pressure fluctuation according to the level of molten metal in the container. A check control device for molten metal in an electromagnetic pump type automatic pouring machine, characterized in that it is equipped with a function generator for check voltage control that issues a thrust command to compensate.