JP2010099666A - Molten metal distribution method in molten metal retaining furnace for casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molten metal distribution method, for automatically distributing molten metal from a molten metal retaining furnace for replenishment without oxidizing molten metal in molten metal retaining furnaces for casting, and easily managing the amount of the molten metal in the molten metal retaining furnaces for casting. <P>SOLUTION: Molten metal in the molten metal retaining furnace for replenishment, molten metal in optional one molten metal retaining furnace for casting and molten metal in the respective molten metal retaining furnaces for casting are communicated via a communication pipe having a siphon function, respectively, while performing management in such a manner that the molten metal level in the molten metal retaining furnace for replenishment is controlled to a range within a low molten metal level at which the siphon effect in the communication pips is not destroyed and within a high molten metal level at which the molten metal in the respective molten metal retaining furnaces for casting does not overflow, the molten metal in the molten metal retaining furnace for replenishment is distributed into the respective molten metal retaining furnaces for casting by the siphon action of the communication pipe. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method for distributing molten metal in a molten metal holding furnace for distributing molten metal to a molten metal holding furnace for casting that stores molten metal supplied to a casting machine such as a die casting machine or a low pressure casting machine.

A casting machine such as a die casting machine or a low pressure casting machine is provided with a molten metal holding furnace for each casting machine, and the molten metal produced in the melting furnace is appropriately distributed to the molten metal holding furnace. It is.

As a hot water distribution method, a molten metal transfer rod having a lid is connected to a molten metal holding furnace for replenishment, and a plurality of hot water distribution rods are connected in parallel to the molten metal transfer rod, and each of the molten metal distribution rods is used for casting. There is a method in which the molten metal stored in the replenishing molten metal holding furnace is distributed to the casting molten metal holding furnace via the molten metal transfer tub and the distributed water tub by connecting the molten metal holding furnace (Patent Document 1). .

In addition, as a method of transferring the molten metal for the hot water distribution tank to the molten metal storage tank, each pipe end of the inverted U-shaped distribution pipe is positioned in the molten metal for the hot water distribution tank and the molten metal storage tank, respectively. There is a method in which a vacuum exhaust unit is provided at an upper position of the hot water distribution pipe and the molten metal is transferred from the hot water distribution tank to the molten metal storage tank by a siphon action (Patent Document 2).
Japanese Patent Laid-Open No. 61-046367 JP-A-6-269919

Since the molten metal transfer iron and the hot metal molten metal described in Patent Document 1 are composed of a steel plate iron part lined with a heat insulating material and a lid part that closes the upper opening of the collar part, When the part receives heat from the molten metal and expands thermally, the heat insulating material cracks or breaks, resulting in poor durability. In addition, although it is essential to prevent oxidation of the molten metal, it is practically difficult to ensure the airtightness between the lid and lid, so take anti-oxidation measures such as supplying inert gas into the bowl. The equipment or control system becomes complicated accordingly. Furthermore, since the distribution of molten metal to each molten metal holding furnace is performed by managing the amount of molten metal decreased in each molten metal holding furnace, a control system for managing the amount of molten metal in the molten metal holding furnace for casting. There is a problem that becomes complicated.

On the other hand, since Patent Document 2 uses an inverted U-shaped connecting pipe having a siphon function to transfer the molten metal, there is an advantage that airtightness can be secured and oxidation of the molten metal in the hot water distribution can be achieved. Similarly to Patent Document 1, it is necessary to manage the amount of decrease in the molten metal in the molten metal storage tank, and there is a problem that the control system for managing the amount of molten metal in the molten metal storage tank becomes complicated.

According to the present invention, the molten metal in each casting melt holding furnace installed for each casting machine does not have the same molten metal reduction ratio (weight reduction rate) depending on the casting operation status. However, there is a difference between the upper and lower molten metal levels between the molten metal holding furnace and the molten metal holding furnace connected by a communication pipe having a siphon function. Pay attention to the fact that the molten metal is transferred from the holding furnace to the casting molten metal holding furnace on the lower molten metal level side, and that the molten metal is automatically stopped if the molten metal level is the same. It has been done.

In order to solve the problems in the conventional method, the present invention comprises a replenishing molten metal holding furnace and a plurality of casting molten metal holding furnaces, and the molten metal in the replenishing molten metal holding furnace is used as the molten metal holding furnace for each casting. In the hot water distribution method of distributing hot water to
The molten metal in the molten metal holding furnace, the molten metal in one of the molten molten metal holding furnaces, and the molten metal in the molten molten metal holding furnaces are communicated with each other via a communication pipe having a siphon function. The molten metal level in the molten metal holding furnace is controlled to be within a range between a low molten metal level that does not destroy the siphon action in the communication pipe and a high molten metal level that does not overflow the molten metal in the casting molten metal holding furnace. However, the molten metal in the replenishing molten metal holding furnace is distributed to the casting molten metal holding furnaces by the siphon action of the communication pipe.

As is apparent from the above description, according to the present invention, the hot water distribution is not performed by the passage formed by the flange portion and the lid portion as in the prior art, but is performed by the communication pipe. A gap or the like does not occur due to a crack in the connection portion or thermal expansion, so that there is no leakage of hot water, and it is not necessary to supply an inert gas into the communication pipe to prevent oxidation of the molten metal.

Also, the molten metal holding furnace for replenishment and the molten metal holding furnace for casting are connected by a communication pipe, and the molten metal level between the holding furnaces is made the same level by the siphon action of the communication pipe.
Therefore, when the amount of molten metal in any of the molten metal holding furnaces decreases, the decrease finally appears as a change in the surface of the molten metal holding furnace for replenishment. Therefore, unlike the conventional method, it is not necessary to manage the molten metal storage amount for each casting molten metal holding furnace and supply the molten metal directly. It is only necessary to manage the molten metal stored amount in the molten metal holding furnace. System management is easy.

In addition, each molten metal holding furnace automatically complements the molten metal with the adjacent molten metal holding furnace, so that the shortage of molten metal in the specific molten metal holding furnace can be avoided and stable casting work can be continued. Can do.

Furthermore, even when restarting after the casting line is stopped, the molten metal levels of all the molten metal holding furnaces are the same, so that the operation can be started smoothly.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a facility for carrying out molten metal distribution in a molten metal holding furnace for casting according to the present invention.
In the figure, Ta is a replenishment holding furnace, a steel plate main body 1 lined with a heat insulating material 2, and a steel plate lid member 4 lined with a heat insulating material 2 that closes the upper surface of a hot water storage section 3 provided on the main body 1. And is installed at the same horizontal position as the molten metal holding furnace Tb (Tb ₁ ).

The lid member 4 is provided with a float type hot water level sensor 5. The float type hot water level sensor 5 has a low hot water level α for supplying molten metal to the hot water storage section 3 and a high hot water surface for stopping the supply of molten metal. Level β is set.

When the float type hot water level sensor 5 detects that the hot water surface level in the hot water storage section 3 of the replenishing molten metal holding furnace Ta has become the lower hot water surface level α, a new molten metal is supplied to the replenishing holding furnace Ta. Thus, for example, if the hot water level rises as the molten metal is supplied and a high hot water surface level β is detected, the fact that the hot water is full is notified and the molten metal supply is stopped. The lower hot water surface level α of the float type hot water surface sensor 5 is set at a position above the lower end surface of the vertical pipe portion 12 so that the siphon function of the communication pipe 10 described below is not destroyed.

Further, the hot water level sensor for detecting the low or high hot water surface level is not limited to the float type hot water surface sensor, and for example, an electrode type hot water surface sensor may be used. In this case, the low hot water surface level is detected. An electrode type hot water level sensor and an electrode type hot water level sensor for detecting a high hot water level are provided.

Tb (Tb ₁ ) is a molten metal holding furnace for storing a molten metal to be supplied to a casting machine such as a die casting machine or a low pressure casting machine (not shown), and a main body 6 made of a steel plate lined with a heat insulating material 7 and provided on the main body. And a lid member 9 made of a steel plate lined with a heat insulating material 7 that closes the upper surface of the hot water storage section 8.

Further, in the figure, only _one casting melt holding furnace Tb ₁ is shown, but a plurality of casting melt holding furnaces Tb ₂ , Tb ₃ ,... ing. Furthermore, a molten metal holding furnace for casting may be disposed on the right side of the figure.

Note that the capacity of the hot water storage section 3 of the replenishment molten metal holding furnace Ta is larger than the capacity of the respective hot water storage sections 8 of the casting molten metal holding furnaces Tb ₁ , Tb ₂ ,.

The replenishment holding furnace Ta, the casting molten metal holding furnace Tb ₁ , the casting molten metal holding furnace Tb ₁ and Tb ₂ , Tb ₂ and Tb ₃ ,... Are horizontally provided with vertical pipe portions 12 and 12 at both ends. The hot water storage units 3, 8 and the hot water storage units 8 are connected to each other by a substantially inverted U-shaped communication pipe 10 constituted by the straight pipe unit 11.

  The vertical pipe parts 12 and 12 and the horizontal straight pipe part 11 are connected by a joint 13, and the whole is covered with a heat insulating material 14, and the inside of the pipe can be kept warm by a heater 15. Further, the horizontal straight pipe part 11, the vertical pipe part 12 and the joint 13 are made of a member having resistance to melting, such as silicon nitride ceramics.

A vacuum exhaust unit 16 is provided at a substantially central portion of the horizontal straight pipe part 11 of the communication pipe 10. That is, a storage part 17 made of a member having resistance to damage such as silicon nitride ceramics is interposed between the horizontal straight pipe parts 11, and the opening part of the storage part 17 is a lid member 18 made of a heat insulating material. It is blocked. The lid member 18 is provided with a float type hot water level sensor 19 for detecting the level of the hot water level and an electrode type hot water level sensor 20 for detecting an abnormal rise of the molten metal. A lower hot water surface level a for starting the vacuum exhaust in the vacuum exhaust section 16 and an upper hot water surface level b for stopping the vacuum exhaust are set. A vacuum pump 21 that is operated by the sensors 19 and 20 communicates with the storage portion 17 through a pipe P. In addition, 22 is a vacuum filter, 23 is a first electromagnetic valve, 24 is a vacuum regulator, 25 is a needle valve, and 26 is a second electromagnetic valve for opening the vacuum pump 21 to the atmosphere.

Next, a method for distributing molten metal will be described with reference to FIG.

Prior to the operation of the casting machine, the molten metal produced in the melting furnace (not shown) is supplied to the molten metal holding furnace Ta and the molten metal holding furnaces Tb ₁ , Tb ₂ ,. The molten metal holding furnace Ta and the casting molten metal holding furnaces Tb ₁ , Tb ₂ ,... Of the hot water storage parts 3, 8 from the molten metal supply port (not shown) to the hot water storage surface levels of the holding furnaces Ta, Tb ₁ , Tb ₂ ,. Are supplied so that the lower end of the vertical pipe portion 12 of each communication pipe 10 is immersed in the molten metal.

In this state, the first electromagnetic valve 23 is opened, the second electromagnetic valve 26 is closed, and the vacuum pump 21 is operated to evacuate the communication pipe 10.

Due to the evacuation, the molten metal flows into the horizontal straight pipe 11 and the storage part 17 from both the vertical pipe parts 12, 12, and when the molten metal reaches the upper hot water level b in the storage part 17, The operation is stopped and the first electromagnetic valve 23 is closed. In this case, the second solenoid valve 26 is kept closed. In this state, the hot water storage parts 3 and 8 of each holding furnace are in a communication state, and the communication pipe 10 has a siphon function.

Next, the casting operation is started in each casting machine, and when the molten metal holding furnaces Tb ₁ , Tb ₂ ,... Are consumed for casting, each molten metal for casting depends on the operation mode or operational status of each casting machine. A change occurs in the hot water level in the hot water storage section 8 of the holding furnaces Tb ₁ and Tb ₂ . However, the molten metal holding furnace Ta and the molten metal holding furnace Tb communicate with each other via the communication pipe 10, and therefore, from each holding furnace, the holding furnace having a relatively high level surface level. The molten metal is automatically transferred to the holding furnace at the lower level by the siphon action.

As described above, as the molten metal in each of the casting molten metal holding furnaces Tb is consumed, the molten metal level in the replenishing molten metal holding furnace Ta also decreases, and the molten metal surface level is set to the set lower molten metal surface level α ( When the float type surface sensor 5 detects that the molten metal replenishment level has been reached, a replenishment command is issued, and the molten metal is supplied from the melting furnace to the molten metal holding furnace Ta.

Then, the liquid level rises as the molten metal is supplied, and when the float type molten metal level sensor 5 detects that the molten metal has reached the set high molten metal surface level β (replenishment stop level), a stop alarm is issued, Supply is stopped.

During the operation, the float type hot water level sensor 19 detects that the molten metal in the reservoir 17 has decreased due to air leakage, that is, has reached a lower hot water level a which is a danger zone that destroys the siphon action. Then, the first electromagnetic valve 23 is opened and the vacuum pump 21 is operated. When the molten metal surface reaches the upper molten metal surface level b, the first electrode valve 23 is closed and the vacuum pump 21 is stopped. Is.

In place of the float type hot water level sensor 19, an electrode type hot water level sensor for detecting a lower hot water level for operating the vacuum pump 21 and an electrode type hot water level sensor for detecting the upper limit hot water level for stopping the operation of the vacuum pump. May be used.

Further, the second solenoid valve 26 is opened in the event of an emergency such as an earthquake or when the molten metal in each holding furnace is taken out at the time of shutting down, and is returned to the holding furnace in which the molten metal in the communication pipe 10 is communicated. is there.

It is sectional drawing which shows the installation applied to the hot water distribution method in this invention.

Explanation of symbols

A molten metal holding furnace for supplying Ta,
Tb ₁ , Tb ₂ , ... molten metal holding furnace for casting,
1,6 body,
3,8 Hot water storage,
4,9 lid member,
5, 19 Float type hot water level sensor,
10 communication pipe,
11 Horizontal straight pipe section,
12 Vertical pipe section,
16 Vacuum exhaust part,
20 electrode level sensor,
21 vacuum pump,
23 1st solenoid valve,
26 Second solenoid valve.

Claims (1)

In the hot water distribution method, which comprises a molten metal holding furnace for replenishment and a plurality of molten metal holding furnaces for casting, and distributes the molten metal in the molten metal holding furnace for replenishment to each molten metal holding furnace for casting,
The molten metal in the molten metal holding furnace, the molten metal in one of the molten molten metal holding furnaces, and the molten metal in the molten molten metal holding furnaces are communicated with each other via a communication pipe having a siphon function. The molten metal level in the molten metal holding furnace is controlled to be within a range between a low molten metal level that does not destroy the siphon action in the communication pipe and a high molten metal level that does not overflow the molten metal in the casting molten metal holding furnace. However, a molten metal distribution method in the casting molten metal holding furnace is characterized in that the molten metal in the replenishing molten metal holding furnace is distributed to the casting molten metal holding furnaces by a siphon action of the communication pipe.

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