JPS6359790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a melting furnace having a pressurized water distribution device.

[Conventional technology]

Conventionally, various types of industrial kilns, such as pressurized pouring furnaces and closed heat-retaining furnaces, have been known as devices for quantitatively feeding molten metal into molds and the like.

[Problems with the prior art] In the case of this type of industrial kiln, the main purpose is to supply molten metal to the mold accurately and quantitatively, so a furnace separate from the molten metal storage furnace (or forehearth) is used. It was necessary to install a melting furnace to melt the metal lumps. For this reason, since two devices, a storage furnace and a melting furnace, are used, the structure of the industrial kiln becomes large, and it is not possible to quickly supply a large amount of stored molten metal. In addition, there was a risk of danger occurring when transferring molten metal from the melting furnace to the storage furnace.

[Purpose of the invention]

In view of the above-mentioned conventional problems, the present invention has been made to melt metal lumps safely and stably, to continuously perform the melting, and to melt the molten metal stored in the hot water storage tank without interrupting the melting process. It is an object of the present invention to provide a melting furnace with a pressurized molten metal distribution device that can maintain cleanliness and distribute molten metal to the outside of the furnace without being contaminated by foreign substances derived from furnace materials or the like.

[Means for solving problems]

In order to solve the above problems, the present invention provides a melting furnace having a melting deck for melting metal lumps and a hot water storage tank for storing the molten metal, and a pipe having a pressurizing port and a discharge port and communicating with the hot water storage tank. It is characterized by comprising a hot water chamber, a hot water distribution pipe in which a molten metal inlet is located in the hot water distribution chamber, and a pressure control device that controls overflow pressure in the hot water distribution chamber.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are diagrams showing the structure of a melting furnace with a pressurized hot water distribution device according to an embodiment of the present invention. In the figure, the melting furnace is made of a material such as silica board that has fire resistance and heat insulation properties, and includes a melting chamber 2 in which a metal ingot 1 is melted and a distribution chamber 3 for distributing molten metal. It is formed. Metal lump 1 is
It is an ingot of a size suitable for melting, etc. The melting chamber 2 is formed in a substantially sealed box shape, and inside thereof there is a melting chamber 4 formed in the shape of a table for placing the metal lump 1, and a hot water storage tank 5 for storing the molten metal. is formed. The upper surface position of the melting deck 4 is formed in the middle of the melting chamber 2 in the height direction, and is slightly inclined (approximately 5 degrees) toward the hot water storage tank 5, so that the molten metal flows into the hot water storage tank 5. It is designed to be stored as molten metal 6. In this embodiment, the ratio of the bottom area occupied by the melting deck 4 and the hot water storage tank 5 is approximately 6:4. An input port 7 for the metal lump 1 is formed on the upper side wall of the melting chamber 2 on the side where the melting deck 4 is formed, and a lid 8 is provided to cover and seal the input port 7 from the outside. . A resistive heating element 9 such as a panel heater having rod-shaped silicon carbide or nichrome wire is provided on the entire upper surface of the melting chamber 2, and this heating element 9 is connected to a power source (not shown). The melting chamber 2 includes an atmosphere temperature measuring element 10 which penetrates its upper wall and has a detection end disposed near the metal lump 1 inside, and a hot water storage tank 5 which penetrates its lateral wall obliquely and has a detection end. A molten metal temperature sensing element 11 disposed inside the molten metal 6 is provided. Further, the melting chamber 2 is provided with a molten metal level sensor 12 that penetrates the upper wall thereof and whose detection end is disposed near the upper surface of the molten metal 6 in the hot water storage tank 5. The ambient temperature sensor 10 and the molten metal temperature sensor 11 are connected via a temperature controller 13 and an overheat alarm 14, respectively, and the molten metal level sensor 12 is directly connected to a temperature controller 15 (a programmable controller). or sequencer).
The ambient temperature thermometer 10 detects the ambient temperature near the metal lump 1 on the melting deck 4, and the molten metal temperature thermometer 11 detects the temperature of the molten metal 6. and,
The temperature control device 15 performs temperature control by comparing the detected temperature with the temperatures set by the temperature controller 13 and the overheat alarm meter 14, respectively. That is, the temperature control device 15 performs temperature control (including overheating prevention, etc.) by controlling (for example, on/off control) the amount of heat supplied to the heating element 9 based on the comparison temperature. The temperature control device 15 also controls the temperature of the molten metal 6 in the hot water storage tank 5 using the molten metal level sensor 12.
By detecting the level, over-melting is prevented so that the molten metal does not rise above the upper surface of the melting deck 4.

The hot water distribution chamber 3 is sealed and formed into a box shape that is slightly smaller than the melting chamber 2.
The hot water storage tank 5 is connected to the side wall of the hot water storage tank 5 with the bottom surface at a common level, and is integrally formed. Further, the hot water distribution chamber 3 is formed higher than the upper surface of the melting deck 4 and slightly lower than the melting chamber 2. That is, the hot water distribution chamber 3 and the hot water storage tank 5 form a molten metal tank that is elongated and communicates with each other and stores the molten metal 6. In this embodiment, the ratio of the bottom areas occupied by the hot water storage tank 5 and the hot water distribution chamber 3 is approximately 2:1. The total storage volume of the hot water storage tank 5 and the hot water distribution chamber 3 is set to a sufficient volume when the metal lump 1 is completely melted. In addition, the hot water distribution room 3
A pressurizing port 16 for introducing gas to pressurize the interior of the hot water distribution chamber 3, and an exhaust port 17 for discharging the body and releasing the pressure are provided at the upper part of the tank. The above pressure port 16
is piped outside and connected to a pressure source 19 with a pressure valve 18 interposed in the middle. This pressurization source 19 is, for example, a device capable of supplying pressurized gas such as air compressed by a compressor or an inert gas. The pressurizing valve 18 is a solenoid valve or the like that opens and closes based on a predetermined control signal from a pressurizing control device 20, which will be described later. Further, the exhaust port 17 is externally connected to an exhaust valve 21 via piping, and is opened to the atmosphere. Above exhaust valve 2
Reference numeral 1 denotes a solenoid valve or the like that is opened and closed based on a predetermined control signal from the pressurization control device 20 or manually. Furthermore, the hot water distribution chamber 3 is provided with a hot water distribution pipe 22 made of a heat-resistant material such as ceramics. One end of the metal distribution pipe 22 is opened at the bottom of the metal distribution chamber 3 as a molten metal inlet 23, and the other end is opened from the top of the metal distribution chamber 3 as a molten metal outlet 24 to the outside. has been done. This molten metal outlet 24 communicates with a supplied side (not shown).

The temperature control device 15 and the pressure control device 20 are controlled by a central control device 25. This central control device 25 adjusts the temperature control device 15 and the pressurization control device 20 in response to external hot water distribution requests. That is, when a metal distribution request is made and the molten metal 6 is not sufficiently stored or the molten metal temperature is not appropriate, the pressurization control device 2
Avoid pressurizing by 0. Further, when there is no metal ingot 1 or molten metal 6 even when there is a request for distribution of metal, an instruction to supply the metal ingot 1 is issued.

Next, the operation of the melting furnace having the above configuration will be explained. First, the amount of metal lump 1 required for distributing hot water is poured into the inlet 7.
Place it on the melting deck 4, and close the lid 8 to seal it. Next, the temperature controller 13 is set to a temperature at which the metal lump 1 melts, and the overheat alarm meter 14 is set to a temperature that will not cause overheating, and then heating is started by the temperature control device 15. As a result, the temperature gradually rises and the metal lump 1 melts, flowing from the melting deck 4 into the hot water storage tank 5.
stored. This molten metal is quietly moved from the hot water storage tank 5 to the hot water distribution chamber 3 as molten metal 6.
Dissolution continues until a predetermined liquid level is reached. metal lump 1
The melting temperature of the metal and the temperature of the molten metal 6 are controlled by a temperature control device 15, and the liquid level is also detected by a molten metal level sensor 12, and is controlled to a level that does not over-dissolve. At this time, impurities such as oxides generated from the molten metal lump 1, foreign substances derived from the furnace materials, etc. are separated from the molten metal and stored in a suspended state on the surface of the molten metal. Next, in response to a hot water distribution request from the outside, the pressurization control device 20 closes the exhaust valve 21 and opens the pressurization valve 18 under the control of the central control device 25. As a result, the pressure source 19
From there, a gas such as compressed air or inert gas flows into the hot water supply chamber 3, and the internal pressure increases. Due to this increase in internal pressure, the molten metal that has been stabilized and held within the molten metal distribution chamber 3 flows into the molten metal distribution pipe 22 from the molten metal inlet 23, flows out from the molten metal outlet 24, and is distributed to the outside.

At this time, since the molten metal inlet 23 is arranged in the middle layer on the bottom side of the molten metal chamber 3, the molten metal is distributed from impurities such as oxides floating on the surface or deposited at the bottom of the furnace, and from furnace materials, etc. No derived foreign matter is mixed in, and a clean portion is supplied.

The pressure inside the hot water distribution chamber 3 during the above-mentioned pressurization is determined by opening the pressurizing valve 18 intermittently in order to maintain the pressurization amount necessary for overflowing based on a method preprogrammed by the pressurizing control device 17. , controlled by repeated closing. For example, as shown in Fig. 4, a pre-programmed method is a method that is based on a graph of the relationship between the amount of melt delivered per unit time and the pressure that has been verified in advance for each individual melting furnace with a pressurized water distribution device. It is set based on the numerical relationship. this is,
This is performed based on settings such as the pressure corresponding to the amount of hot water to be distributed, the number of times and timing of opening and closing of the pressurizing valve 18, and the timer time set to match the required amount of hot water to be distributed.

FIG. 3 is a graph showing the furnace internal pressure and the passage of time during the pressure control described above. That is, the molten metal that has risen in the distribution pipe 22 after pressurization starts, eventually reaches an overflowing pressure and starts distributing the molten metal. The pressurization continues thereafter, and the pressure reaches the pressure set to the pressurization amount that defines the required amount of hot water distributed per unit time, which is set based on the graph of the relationship between the amount of hot water distributed per unit time and the pressure shown in Figure 4 above. When this point is reached, the pressurization is stopped according to an instruction from a pressure regulator provided in the pressurization control device 20. When the molten metal is distributed to the outside through the distribution pipe 22, the pressure inside the furnace decreases, and when the pressure decreases to a level exceeding the hysteresis (adjustment operation gap) of the pressure regulator, it is pressurized again.

That is, as shown in FIG. 3, when a predetermined overflow pressure (ΔP ₁ ) added to the overflow start pressure indicated by the dashed line is reached, the pressure control device 20 controls the pressure control valve 18. is closed to cut off the pressure supply from the pressurization source 19. Then, when the pressure decreases by the hysteresis pressure ΔP ₂ due to hot water distribution, the pressurizing valve 18 is opened again and pressure from the pressurizing source 19 is supplied. Thereafter, by repeating the above operation as shown in FIG. 3, the pressure is controlled as on-off control is repeated at a predetermined timing, and almost quantitative hot water distribution is continued. Then, the exhaust valve 21 is opened by an external stop command, an internal timer of the pressurization control device 20, or manually, the pressure is reduced, and the hot water distribution is stopped.

In the configuration of this invention, from melting to hot water distribution, as explained above, there are two fundamentally important requirements.
Points can be presented.

First, in the structure of the melting furnace with a pressurized hot water distribution device, the metal lump 1 is basically melted on the melting deck 4, and the large metal lump 1 falls from the top of the melting deck 4 into the hot water storage tank 5. However, since the hot water distribution pipe 22 is installed in the hot water distribution chamber 3, which is separate from the hot water storage tank 5 of the melting chamber 2, the hot water distribution pipe 22 may be damaged by the falling metal lump 1. Otherwise, the melting inlet 23 will not be blocked.

FIG. 2 shows the hot water distribution chamber 3 in the pressurization control device 20.
This is a method of pressurization control for Generally, in a pressurized pouring furnace or a molten metal quantitative supply device,
In both cases where preliminary pressure (or preparation pressure) to a fixed point is required to enable pouring and pressurization, or in which case it is not required, the configuration from pressurization to evacuation is designed to handle a limited amount of molten metal. This is a short-term one cycle for quantitative supply.

However, in the present invention, the pressurizing valve 18 is repeatedly opened and closed based on the pre-programmed method as described above, and the furnace pressure is controlled so as to show the time course as shown in FIG.

It can be easily inferred that the amount of time that quantitative metal distribution can continue will eventually reach its limit under control using this hysteresis pressure ΔP ₂ due to a decrease in the molten metal in the metal distribution chamber 3. However, in our experience, the structure of the hot water storage tank 5 and the hot water distribution room 3 has been devised so that the amount of hot water commensurate with the amount of melted hot water distributed within a practically necessary and sufficient unit time can be achieved once or twice as described above. It has been realized that hot water can be distributed according to the hot water distribution cycle.

To give you an example, the amount of dissolution per hour is 150
The time required to distribute 150 kg of hot water per kg is
It has been confirmed that the total time is 100 seconds.

In the above embodiment, the hot water distribution chamber 3 only needs to be formed so that it communicates with at least the hot water storage tank 5 of the melting chamber 2 so that the molten metal 6 flows into it.
The shape, structure, etc. do not have to be integral as in the embodiment.

Furthermore, the molten metal inlet 23 of the molten metal distribution pipe 22 may be disposed at a middle layer on the bottom side sufficiently lower than the molten metal level, and the molten metal outlet 24 may be disposed at a position higher than the molten metal level.

〔Effect of the invention〕

As explained above, in the sealed melting furnace according to the present invention, the pressurized melting furnace is capable of stably, safely, and quantitatively distributing the clean portion of the molten metal that is highly efficient in terms of heat balance. It became possible to have a melting furnace with a hot water distribution device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a melting furnace with a pressurized hot water distribution device according to an embodiment of the present invention, where a is a cross-sectional view taken along the line A-A in FIG. 2, and FIG. Figure 2a is a plan view of the melting furnace with pressurized water distribution device,
Figure 2b is a cross-sectional view taken along the line C-C in Figure 1b, Figure 3 is an operating characteristic graph showing pressure changes in the furnace during distribution, and Figure 4 is a graph showing the distribution per unit time that is individually verified. It is a hot water amount-pressure relationship graph. 1... Metal lump, 2... Melting chamber, 3... Hot water distribution room, 4... Melting deck, 5... Hot water storage tank, 6... Molten metal 6, 7... Inlet, 8... Lid, 9... Heating element, 10... Ambient temperature Temperature measuring element, 11... Molten metal temperature measuring element, 12... Molten metal level sensor, 13... Temperature controller, 14... Overheat alarm meter, 15... Temperature control device, 16... Pressurizing port, 17...
Exhaust port, 18... Pressurization valve, 19... Pressure source, 20... Pressure control device, 21... Exhaust valve, 22... Hot water pipe, 23
... Molten metal inlet, 24... Molten metal outlet, 25... Central control device, ∆P ₁ ... Overflow pressure, ∆P ₂ ... Hysteresis pressure.

Claims (1)

[Claims] 1. A melting deck 4 of a melting furnace having an inlet 7 for the metal lump 1 and for holding the metal lump 1 and receiving the amount of heat necessary for melting it, and a hot water storage tank 5 for storing the molten metal 6. A molten metal level sensor 12 detects the stored amount of molten metal, a heating element 9 supplies a predetermined amount of heat necessary for melting the metal lump 1 on the melting deck 4, and measures the temperature of the molten metal and the temperature of the atmosphere, respectively. a hot water distribution chamber 3 having a pressurizing port 16 and a discharge port 17 and communicating with the hot water storage tank 5; and a molten metal inlet 23 in the hot water distribution chamber 3.
A melting furnace with a pressurized hot water distribution device, characterized in that it comprises a hot water distribution pipe 22 in which a hot water distribution pipe 22 is located, and a pressurization control device 20 that controls the overflow pressure in the hot water distribution chamber 3.