JPH10175050A - Fixed molten metal surface melting and holding furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the surface level of molten metal to a fixed position by preventing a failure caused by elevating/lowering of the molten metal. SOLUTION: This molten metal holding furnace is provided with an elevating/ lowering means 32 for elevating/lowering an immersion body between two positions of an upper limit position where the immersion body 30 rises from the molten metal surface and a lower limit position a where the whole immersion body sinks below the molten metal surface, a set molten metal surface detecting means 36a for detecting whether the molten metal surface in the molten metal holding chamber 20 exists in the set level or not, a tap 26 in the molten metal for opening/closing a transfer passage 24 of the molten metal, an actuator 27 for driving open/close of the tap 26 in the molten metal and a molten metal surface level control means 37 for controlling the actuator 27 and the elevating/lowering means 32 so that the tap 26 in the molten metal opens when the molten metal surface lowers below the set level based on a molten metal detecting signal while keeping the immersion body 30 to the lower limit position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant melting furnace for supplying molten metal to a casting machine such as a die casting machine.

[0002]

2. Description of the Related Art Conventionally, molten metal supplied to a casting machine such as a die-casting machine is stored in a holding furnace to maintain a constant temperature, and is supplied to the casting machine by an electromagnetic pump or the like. As this type of holding furnace, a holding furnace having a function of maintaining a constant level of the molten metal is used. In such a holding furnace, an immersion body is lowered in accordance with a decrease in the level of the molten metal to keep the level of the molten metal constant (for example, Japanese Patent Publication No. 2-3078).
No. 7 publication) is known.

Conventionally, in order to maintain the level of the molten metal at a constant level by this immersion method, an elevating device for raising and lowering the immersion object and a position of the immersion object or the level of the immersion object to detect the level of the immersion object. A control device for controlling the position accurately is provided.

[0004]

However, in the conventional immersion body type constant temperature control, since the immersion body is frequently moved up and down, there are the following problems. Repeatedly raising and lowering the immersion body, oxide film formed on the surface of the immersion body,
The surface of the immersed body is deteriorated and a part of the immersed body is peeled off. When the immersed body sinks into the molten metal, it enters the molten metal. In order to prevent this, the maintenance frequency of the immersion body had to be increased. Further, there is a problem that the temperature of the molten metal fluctuates in accordance with the amount of sinking of the immersion body in the molten metal, that is, if the amount of sinking of the immersion body is large, the change in the temperature of the molten metal also increases.

[0005] A molten metal such as aluminum or magnesium (including an alloy) is active, and absorbs a much larger amount of hydrogen gas in a molten state than in a solid state. Therefore, hydrogen gas is inevitably contained in the molten metal, and this hydrogen gas is trapped as bubbles in the structure of the casting during the solidification process of the molten metal. The presence of these bubbles causes porosity defects, and lowers mechanical properties such as strength and toughness of the cast product.

Further, inclusions inevitably mixed into the molten metal during the casting process not only reduce the mechanical strength such as strength and toughness, but also cause surface damage of the cast product and tools during the cutting process. This may lead to breakage of the surface and greatly affect the surface treatment properties.

[0007] Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, to prevent the above-mentioned problems caused by raising and lowering of the immersion body, and to maintain a constant level of molten metal. An object of the present invention is to provide a surface melting and holding furnace.

Another object of the present invention is to provide a constant temperature melting furnace having a function of effectively removing hydrogen gas and inclusions present in the molten metal.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a molten metal melting chamber in which a casting material is heated by a heating device to store molten metal, and a molten metal to be supplied to a casting machine. The molten metal holding chamber is divided into a furnace main body, a molten metal transfer passage for supplying the molten metal in the molten metal melting chamber to the molten metal holding chamber is formed in the furnace main body, and an immersion body is disposed inside the molten metal holding chamber so as to be movable up and down. A constant temperature melting and holding furnace in which the immersion body is immersed in the molten metal so as to maintain the level of the molten metal in the molten metal holding chamber at a predetermined set level; Raising and lowering means for raising and lowering the immersion body between a position and a lower limit position where the entire immersion body has settled below the surface of the molten metal; and whether or not the surface of the molten metal holding chamber is at a set level. Setting level detection means for detecting
A tap for opening and closing the transfer passage for the molten metal, an actuator for driving the tap for opening and closing the tap, and the level of the molten metal dropped below a set level based on the level detection signal while holding the immersion body at the lower limit position. And a level control means for controlling the actuator and the elevating means so that the tap in the hot water is sometimes opened.

According to the present invention having the above-described structure, the immersion body is opened and closed along the top and bottom of the molten metal while maintaining the lower limit position where the entire immersion body is immersed in the molten metal. Level is kept constant. In the meantime, in the molten metal holding chamber, since the immersion body remains settled in the molten metal at the lowermost position, it is possible to solve the problem caused by repeatedly raising and lowering the immersion body as in the related art.

In the present invention, the level of the molten metal in the molten metal holding chamber when the dipped body is raised to the upper limit position is set to a position lower than the suction pipe of the molten metal feeding device for supplying the molten metal to the casting machine. According to this, the level of the molten metal is lowered by the amount of drained water from the immersion body, and rapid rapid drainage becomes possible.

Further, the present invention provides a molten metal melting chamber for heating a casting material by a heating device to store a molten metal melted therein, a molten metal processing chamber communicating with the molten metal melting chamber for purifying the molten metal, and a casting machine. A molten metal holding chamber for storing the molten metal to be supplied is partitioned into a furnace main body, and a transfer passage of the molten metal for supplying the molten metal in the molten metal processing chamber to the molten metal holding chamber is formed in the furnace main body. What is claimed is: 1. A constant-temperature melting and holding furnace comprising a level control means for maintaining a level of a molten metal at a predetermined level according to a variation, wherein an inert gas is made into fine bubbles and diffused into the molten metal in the molten metal processing chamber. A molten metal treatment device for purifying the molten metal is provided.

[0013] According to the constant melting surface melting and holding furnace of the present invention, the molten metal melted in the molten metal melting chamber contains hydrogen gas and inclusions inevitably. It is stored in the molten metal processing chamber. In the molten metal processing chamber, the inert gas that has been made into fine bubbles is diffused into the molten metal by the molten metal processing apparatus. As a result, the hydrogen gas and inclusions existing in the molten metal are collected by the bubbles of the injected inert gas, floated together with the bubbles, and removed from the molten metal.

According to a preferred embodiment of the present invention, a change in the level of the molten metal in the molten metal processing chamber is detected, and in the molten metal processing apparatus, the molten metal is replenished from the molten metal melting chamber and the level of the molten metal reaches the set level. Sometimes driven intermittently.

By operating the molten metal processing apparatus in this manner, the processing of removing hydrogen gas and inclusions from the molten metal can be performed effectively as soon as the molten metal is supplied from the molten metal melting chamber.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a furnace for melting and holding a molten metal according to an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a furnace main body of a constant melting point melting and holding furnace according to an embodiment of the present invention, and 12 denotes a base.

The furnace main body 10 is supported by wheels 11 rolling on rails 13 laid on a base 12, and is operated together with the wheels 11 by a moving cylinder 14 which constitutes a moving device. Are connected.

The furnace body 10 has a molten metal melting chamber 18 therein.
And the molten metal holding chamber 20 are a furnace having an integral structure partitioned by a partition wall 22. The molten metal 50 heated by the melting burner 16 as a heating device and melted from the casting material is stored in the molten metal melting chamber 18 and subjected to processing such as degassing and deslagging. A transfer passage 24 that communicates the molten metal melting chamber 18 and the molten metal holding chamber 20 is provided in a partition wall 22 that separates the molten metal melting chamber 18 and the molten metal holding chamber 20. Melt holding chamber 20
Inside, the molten metal 50 is stored while being maintained at a constant molten metal level L.

A seat 25 is attached to the entrance of the transfer passage 24, and a tap 26 in the hot water can be seated on the seat 25. The hot tap 26 is connected to an opening / closing actuator 27 via a rod 28, and the hot tap 26 moves up and down by driving the actuator 27, thereby opening and closing the entrance of the transfer passage 24. I have.

On the other hand, the immersion body 30 is
Are provided so as to be movable up and down. The surface of the immersion body 30 is formed of a material made of a molten metal. The immersion body 30 is supported so as to be immersed in the molten metal 50 from directly above the furnace by an elevating device 32 attached via a bracket 31. The lifting device 32 is provided with the immersion body 3
Reel 34 around which wire 33 directly connected to 0 is wound
And a motor 35 for driving the reel 34 to rotate. The lower limit position of the immersion body 30 shown by a solid line in FIG.
The immersion body 30 is moved up and down between an ascending limit position indicated by a two-dot chain line.

A molten metal level setting device 36a using a thermocouple is disposed in the molten metal holding chamber 20, and the position of the tip of the molten metal level setting device 36a is set during the casting process. The position is adjusted to a position corresponding to the level L which is the level. The level setting unit 36 a is connected to the control device 37. The control device 37 includes a central processing unit (CPU) and includes a set level detecting means for detecting whether or not the level is at a set level L from a level detection signal provided from a level setting unit 36a. It is configured together with the level setting unit 36a, controls the motor 35 of the elevating device 32 as described later, and opens and closes the in-water tap 26 so that the level of the level is maintained at the set level L. The actuator 27 is controlled.

The level of the molten metal in the molten metal holding chamber 20 is as follows:
In addition to the set level L, the set levels L1 and L3
Is set. Of these, the set level L1 is the level of the molten metal when the immersed body 30 rises above the molten metal, and is set at a position lower than the position of the suction pipe 38 attached to the side wall of the furnace body 10. . In this case, in relation to the set level L, the level of the molten metal is lowered by the volume V of the immersion body 30.

The set level L3 is such that when the molten metal level in the molten metal melting chamber 18 is L2, the dipped body 30 is raised above the molten metal level, and the molten metal level when the tap 26 is opened at that time. Level. In this case, in relation to the set level L2 of the molten metal melting chamber 18, the molten volume in the molten metal melting chamber 18 flows into the molten metal holding chamber 20 and the inflow volume V1 when the molten metal surface falls from L2 to L3 is equal to the inflow volume V1. L1 and L
It corresponds to the volume of the level difference of 3. Therefore, tap 2
6, the molten metal melting chamber 18, the molten metal holding chamber 20
The same level L3 lower than the suction pipe 38
It is supposed to be. Therefore, for example, even if a malfunction occurs in the tap 26 in the molten metal and a molten metal leaks from the molten metal melting furnace 18 to the molten metal holding chamber 20, if the level of the molten metal is set as described above, the inside of the molten metal holding chamber 20 can be reduced. The molten metal does not overflow into the molten metal supply system.

Also in the molten metal melting chamber 18, a level setting unit 36b for setting the level to L2 is provided, and the level comes into contact with the level setting unit 36b, and the detection signal is controlled. When given to the device 37, the control device 3
7 extinguishes the melting burner 16 and controls the melting burner 16 to ignite when the molten metal level falls below L2, so that the molten metal melting chamber 18 has a constant molten metal level at L2 during the casting operation. Is to be retained. The molten metal level L2 of the molten metal melting chamber 18 is set higher than the set molten metal level L of the molten metal holding chamber 20 by the head [Delta] h. Thereby, the molten metal can flow into the molten metal holding chamber 20 through the transfer passage 24.

The suction pipe 38 is connected to a discharge pipe 42 of an electromagnetic pump 40 as a molten metal pumping device. The discharge pipe 42 of the electromagnetic pump 40 is detachably connected to a hot water supply pipe of a casting machine (not shown). When the cylinder 14 advances, the entire furnace body moves to the casting machine side along the rail 13 and is indicated by a two-dot chain line in the figure. At the position indicated by, the discharge pipe 42 is connected to the hot water supply pipe of the casting machine.

Next, the operation of the present embodiment configured as described above will be described. First, when the molten metal 50 stored in the molten metal melting chamber 18 is supplied to the molten metal holding chamber 20, the control device 37 places the immersion body 30 at the lower limit position in FIG. Give a command. When the tap 26 is opened, the molten metal melting chamber 18 is opened.
Is supplied to the molten metal holding chamber 20 through the transfer passage 26. In the molten metal holding chamber 20, the level of the molten metal 50 gradually increases, but the control device 37
Is stopped, and the position of the immersion body 30 is held at the lower limit position.

Eventually, when the molten metal level reaches L, the molten metal level comes into contact with the tip of the molten metal level setting device 36a, and the control device 37 detects from the detection signal that the molten metal level has reached the set level L. Then, a signal to close the hot water tap 36 is output to the actuator 27. Thus, the molten metal holding chamber 20
In, the molten metal level is accurately maintained at the set level L.

Next, during the casting operation, the molten metal level in the molten metal holding chamber 20 is maintained as follows.

When the molten metal 50 in the molten metal holding chamber 20 starts to be supplied to the casting machine by the electromagnetic pump 40, the molten metal holding chamber 20
Of the molten metal 50 tends to fall from the set level L.
At this time, the level of the molten metal 50 is set to the level setting unit 36a.
The controller 37 detects that the level of the molten metal has dropped, and the actuator 27 operates to open the tap 26 in the molten metal.
Command.

When the tap 26 in the molten metal is opened and the molten metal 50 in the molten metal melting chamber 18 is sent to the molten metal holding chamber 20, the molten metal holding chamber 2
When the water level of 0 starts to rise and returns to level L, it comes into contact with the water level setting unit 36a, so that the hot tap 26 is closed. During this time, the immersion body 30 is kept at the lowermost position where it is completely immersed in the molten metal 50, and the tap 26 in the hot water is opened and closed along with the rise and fall of the molten metal surface, so that the level of the molten metal surface is maintained at L.

In this way, the molten metal 50 is automatically and efficiently replenished directly from the molten metal melting chamber 18 and the level of the molten metal is maintained at the set level L during that time. In addition, it is possible to prevent deterioration of the quality of the molten metal due to the transfer of the molten metal. Further, temperature fluctuation due to the immersion body 30 can be prevented.

In the molten metal holding chamber 20, since the immersion body 30 remains settled in the molten metal at the lowermost position, the immersion body 30 is repeatedly raised and lowered as in the prior art. The coating and the surface of the immersion body 30 are not deteriorated and part of the immersion body is peeled off, and the immersion body does not enter the molten metal when sinking into the molten metal.

Next, FIG. 2 is a view showing the position of the immersion body 30 when the molten metal in the molten metal holding chamber 20 is quickly drained. In this embodiment, when the push button 44 dedicated to the quick drain operation is pressed, the control device 37 rotates the motor 35 to
The immersion body 30 is raised to the upper limit position. This allows
Since the level of the molten metal drops rapidly to a position lower than the suction pipe 38 by the amount of the molten metal discharged from the immersion body 30, rapid drainage from the molten metal supply system to the molten metal holding chamber 18 becomes possible.

The quick drainage described above is performed by tap 26
In addition to the manual operation using the push button 44 when an abnormality occurs, for example, when a leak occurs in the molten metal supply system, a leak sensor (not shown) is provided. The control device 37 that has detected the hot water leak from the detection output of the above may automatically raise the immersion body 30 to perform the rapid hot water discharge.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a view showing a constant melting surface melting and holding furnace provided with a molten metal treatment device for removing hydrogen gas and inclusions from the molten metal. In the constant melting surface melting and holding furnace of FIG. 3, the same components as those of FIG. 1 are denoted by the same reference numerals.

In this constant melting furnace, the portion where the molten metal melting chamber 18 of FIG. 1 is provided is divided by a partition wall 60 into a molten metal melting chamber 61 and a molten metal processing chamber 62. The molten metal melting chamber 61 and the molten metal processing chamber 62 communicate with each other through an opening 63 formed in the partition wall 60. The molten metal 50 heated by the melting burner 16 and melted from the casting material in the molten metal melting chamber 61 is subjected to molten metal processing. It is temporarily stored in the chamber 62. Then, a process of removing dehydrogenation gas and inclusions is performed by a molten metal processing device 64 mounted and supported above the furnace.

In the partition wall 22 that separates the molten metal processing chamber 62 from the molten metal holding chamber 20, a transfer passage 24 communicating the molten metal processing chamber 62 and the molten metal holding chamber 20 is provided. In the molten metal processing chamber 62, the molten metal 50 is stored while being maintained at a constant level L2.

A seat 25 is attached to the outlet of the transfer passage 24, and a tap 26 in the hot water can be seated on the seat 25. The hot tap 26 is connected to an opening / closing actuator 27 via a rod 28, and the hot tap 26 moves up and down by driving the actuator 27, thereby opening and closing the outlet of the transfer passage 24. I have.

The molten metal processing apparatus 64 includes a main body 70 having a built-in motor, and a discharge pipe 72 connected to a drive shaft of the main body 70 via a joint 71. Main unit 70
Is supplied with an inert gas (for example, argon gas, nitrogen gas, or the like) from a gas pipe 73 connected to an inert gas source. The inert gas passes through a discharge pipe 72. And the rotating body 74 attached to the tip thereof
Is discharged from.

As shown in FIG. 4, the rotating body 74 has a large number of small-diameter discharge ports 75 opened on the lower surface thereof. The rotator 74 discharges the inert gas from the discharge port 75 while rotating, so that the inert gas can be made into fine bubbles and diffused into the molten metal.

The molten metal processing apparatus 64 is suspended by elevating means composed of a rotating reel 76 and a wire 77. When the molten metal holding furnace is in operation, the rotating body 74 rotates the molten metal 5.
0. The operation of the molten metal processing apparatus 64 is as follows.
The operation is controlled by the control device 37 and linked with the elevation of the molten metal level in the molten metal melting chamber 61 and the molten metal processing chamber 62. In this embodiment, the operation is intermittently performed based on the detection signal of the level setting unit 36b for setting the level of the molten metal in the melting chamber 61 to L2.

In the molten metal holding chamber 20, during the casting operation, the immersion body 30 is kept in exactly the same manner as in the embodiment of FIG.
The tap 26 in the hot water is opened and closed with the water still sinking in the molten metal. Thus, the molten metal in the molten metal processing chamber 62 is automatically replenished, and the molten metal level is maintained at a constant L.

Further, the position of the immersion body 30 at the time of rapid drainage (the position indicated by the two-dot chain line in the figure) and the molten metal level L at that time
1 is the same as in the first embodiment, and a description thereof will be omitted.
Next, the operation of the present embodiment configured as described above will be described. FIG. 5 is a time chart showing an operation example of the molten metal processing apparatus 64 during the casting operation. In the molten metal melting chamber 61 and the molten metal processing chamber 62, when the level of the molten metal falls below L2, the molten burner 16 is ignited and the molten metal is newly supplied. Then, in FIG. 5 (a), the level is returned to L2 and the level is set to the level setting unit 36.
When it comes into contact with b (the molten metal level setting device is ON), the molten metal processing device 64 is operated for a certain period of time, in this case, for 5 minutes.

During the operation of the molten metal processing apparatus 64, the rotating body 74 rotates at a high rotation speed of, for example, 500 rpm, and diffuses the inert gas which has become fine bubbles into the molten metal in the molten metal processing chamber 62. . Hydrogen gas and inclusions that existed in the molten metal are collected by bubbles of the injected inert gas, floated together with the bubbles, and removed from the molten metal.

In this way, in the molten metal processing chamber 62, as soon as the molten metal is replenished from the molten metal melting chamber 61, a treatment for removing hydrogen gas and inclusions from the molten metal 50 is effectively added. The molten metal 50 purified by removing the inclusions is supplied.

As shown in FIG. 5B, the operation of the molten metal processing apparatus 64 is such that the level setting unit 36b is turned on.
After that, normal rotation and reverse rotation may be alternately performed for a certain time.

[0047]

[Table 1] Here, Table 1 shows an experimental example of the effect of removing dehydrogenated gas and inclusions by the molten metal processing apparatus 64. Further, as comparative examples, the hydrogen gas amount and the K value by the K mold method under no treatment under the same conditions, and the hydrogen gas amount and the K value under the conventional flux treatment are listed.

Operating conditions Casting material AC4CH Melt volume 500 kg Melt temperature 700 ° C. Argon gas flow rate 20 l / min Rotating body rotation speed 500 rpm Processing time 5 min Measuring method of hydrogen gas amount Lansley method The mold was cast according to Utility Model No. 1206274), the flat portion of the cast product was broken, and the number of inclusions in the fractured surface was measured by visual observation.

As can be clearly seen from Table 1, it is understood that the dehydrogenation gas is more than twice as effective as the conventional one and the inclusion removal is more effective. For the test of dehydrogenation gas, the flux treatment was 3 times.
The operation time of the molten metal processing apparatus 64 is 5 minutes, whereas the operation time is 0 minutes, which is excellent in terms of the time efficiency of the purification processing.

FIG. 6 shows still another embodiment of a constant-temperature-surface-melting / holding furnace provided with a molten-metal processing apparatus. As in the embodiment of FIG. 3, in this constant temperature melting furnace, a partition 60 divides a molten metal melting chamber 61 and a molten metal processing chamber 62, and the molten metal melting chamber 61 and the molten metal processing chamber 62 are formed on the partition 60. The openings 63 communicate with each other. The molten metal 50 heated by the melting burner 16 and melted in the molten metal melting chamber 61 is temporarily stored in the molten metal processing chamber 62.
Here, the molten metal processing device 64 diffuses the inert gas that has been made into fine bubbles from the rotating body 74 immersed in the molten metal 50 into the molten metal 50. Hydrogen gas and inclusions that existed in the molten metal
It is collected by the bubble of the injected inert gas, floats together with the bubble, and is removed from the molten metal. Thus, in the molten metal processing chamber 62, dehydrogenation gas and inclusions are removed. I have.

The partition 22 that separates the molten metal processing chamber 62 from the molten metal holding chamber 20 is provided with a transfer passage 24 that communicates the molten metal processing chamber 62 with the molten metal holding chamber 20. Transfer passage 2
A seat 25 is attached to the entrance of the seat 4, and a tap 26 in the hot water can be seated on the seat 25. The hot tap 26 is provided with an opening / closing actuator 27.
Via a rod 28, and the tap 26 moves up and down by the drive of the actuator 27, thereby opening and closing the entrance of the transfer passage 24.

In this embodiment, a pressurizing chamber 80 is provided in place of the immersion body as a level raising / lowering means for raising / lowering a fluctuating level, so that the level inside the pressurizing chamber 80 is pressurized by a pressure gas. It was done.

The pressurizing chamber 80 is formed in the molten metal holding chamber 20 as a space closed by a partition wall 81 which is hung down so as to be immersed in the molten metal 50. The level of the molten metal is set to the same reference level L3 inside and outside the partition wall 54. This reference level L3 is lower than the height position of the suction pipe 38 as in the embodiment of FIG. The pressurizing chamber 55 is supplied with a pressure gas inactive with respect to the molten metal from a supply pipe 82 via a control valve 83. During the casting process, the level of the molten metal in the molten metal holding chamber 20 is set to a predetermined level. L is maintained.
When the electromagnetic pump 40 is operated and the molten metal in the molten metal holding chamber 20 starts to be supplied to the casting machine, the molten metal level in the pressurizing chamber 80 is further pushed down, and the molten metal level on the suction side of the electromagnetic pump 40 becomes L. It is kept so that it does not fall below.

As means for detecting the position of the molten metal level inside the pressurizing chamber 80 in order to take the timing to open the hot water tap 26,
Non-contact type displacement sensor 84 using laser, ultrasonic wave, etc.
Is provided. The detection signal of the displacement sensor 84 is
Introduced to the control device 37, the control device 37
When it was detected that the inside of the bath had dropped to L4,
The tap 27 is opened by operating the actuator 27.

At this time, the molten metal supplied to the molten metal holding section 20 from the molten metal processing chamber 62 through the passage 24 is purified by removing the hydrogen gas and inclusions by operating the molten metal processing apparatus 64. .

[0056]

As is apparent from the above description, according to the first aspect of the present invention, the immersion body can be moved vertically above and below the surface of the molten metal while maintaining the lower limit position where the entire immersion body is immersed in the molten metal. Accordingly, the tap in the hot water is opened and closed, and the level of the hot water surface is kept constant. In the meantime, in the molten metal holding chamber, the immersed body remains settled in the molten metal at the lowermost position, so it is not necessary to repeatedly raise and lower the immersed body as in the related art, so that the oxide film formed on the surface of the immersed body can be reduced. , The surface is deteriorated and a part of the immersion body is peeled off, and the inconvenience of mixing in the molten metal when the immersed body sinks in the molten metal can be eliminated. This has the advantage that the maintenance of the device is simplified.

According to the third aspect of the present invention,
A molten metal processing chamber is provided between the molten metal melting chamber and the molten metal holding chamber, and a molten metal processing apparatus is provided for purifying the molten metal by purifying the molten metal into fine particles by diffusing inert gas into the molten metal in the molten metal processing chamber. And inclusions are inevitably contained in the melt,
Before being sent to the molten metal holding chamber, it is temporarily stored in the molten metal processing chamber, and then subjected to purification processing by the molten metal processing apparatus. Thereby, the hydrogen gas and inclusions can be effectively removed from the molten metal by the inert gas which has been diffused into the molten metal and has been made into fine bubbles.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a constant temperature melting furnace according to an embodiment of the present invention.

FIG. 2 is a view showing the position of an immersion body when the molten metal in the molten metal holding chamber is quickly drained.

FIG. 3 is a cross-sectional view of a constant temperature melting furnace according to another embodiment of the present invention.

FIG. 4 is a side view showing a rotating body of the molten metal processing apparatus.

FIG. 5 is a time chart showing an operation example of the molten metal processing apparatus during a casting process.

FIG. 6 is a cross-sectional view of a constant melting surface melting and holding furnace according to another embodiment provided with a molten metal processing apparatus.

[Explanation of symbols]

 Reference Signs List 10 furnace body 18 molten metal melting chamber 20 molten metal holding chamber 24 transfer passage 26 tap in hot water 27 actuator 30 immersion body 32 elevating device 36a, 36b level setting device 37 controller 40 electromagnetic pump 62 molten metal processing chamber 64 molten metal processing device 74 rotation Body 80 Pressurizing chamber

Claims (4)

[Claims] 1. A molten metal melting chamber for storing a molten metal heated and melted by a heating device and a molten metal holding chamber for storing a molten metal to be supplied to a casting machine are partitioned into a furnace main body. A molten metal transfer passage for supplying the molten metal from the melting chamber to the molten metal holding chamber is formed, and an immersion body is disposed inside the molten metal holding chamber so as to be able to move up and down, and the immersion body is immersed in the molten metal to melt the molten metal in the molten metal holding chamber. In a constant temperature melting furnace for maintaining the surface at a predetermined set level, a rising end position of a position where the immersed body has risen above the surface of the molten metal,
Elevating means for raising and lowering the immersion body between two positions, that is, a lower limit position of a position where the entire immersion body has settled below the surface of the molten metal, and detecting whether or not the surface of the molten metal holding chamber is at a set level. A set level detecting means, a tap for opening and closing the transfer passage for the molten metal, an actuator for driving the tap for opening and closing the tap, and a signal for detecting the level of the molten metal while holding the immersion body at the lower limit position. And a level control means for controlling the actuator and the elevating means so that the tap is opened when the level falls below a set level. 2. The molten metal level of the molten metal holding chamber when the dipped body is raised to the ascending limit position is lower than a suction pipe of a molten metal feeding device for supplying molten metal to a casting machine. The constant-temperature melting / holding furnace according to claim 1. 3. A molten metal melting chamber for heating a casting material by a heating device and storing the molten metal melted therein, a molten metal processing chamber communicating with the molten metal melting chamber for purifying the molten metal, and a molten metal supplied to the casting machine. A molten metal holding chamber to be stored is partitioned into a furnace main body, a molten metal transfer passage for supplying the molten metal in the molten metal processing chamber to the molten metal holding chamber is formed in the furnace main body, and the molten metal in the molten metal holding chamber is changed according to a change in the amount of the molten metal. A constant melting level melting and holding furnace equipped with a level control means for maintaining a level of a molten level at a predetermined level, wherein an inert gas is finely bubbled and diffused into the molten metal in the molten metal processing chamber to purify the molten metal. A constant-temperature melting and holding furnace, comprising: 4. An operation for detecting a change in the level of the molten metal in the molten metal processing chamber and intermittently operating the molten metal processing apparatus when the molten metal is supplied from the molten metal melting chamber and the molten metal level reaches a set level. 4. The apparatus according to claim 3, further comprising control means.
2. A constant melting surface melting and holding furnace according to item 1.