JPS6237678A - Decompression scouring device for melt - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is a continuous refining facility for melting and refining a molten material containing glass, steel, copper, etc. under reduced pressure.

(Prior Art) Generally, in a glass melting furnace, the melting and refining section of the melting furnace must be maintained at a high temperature for a long period of time in order to melt glass raw materials and remove gas contained in the glass. The effect of this degassing becomes more pronounced at higher temperatures, and it is an important process that affects various properties of glass, such as coloring, viscosity, surface tension, and devitrification.

This requires consuming a large amount of heavy oil as a heating source, installing a heat exchanger such as a hot air stove to heat the air for heating the heavy oil, and using high-grade bricks that are fireproof and resistant to corrosion, which reduces equipment costs. This is an uneconomical melting furnace, which is large in size and the degassing time occupies more than half of the total melting process, resulting in extremely large heat losses.

In addition, in the production of melted glass, it is possible to keep the molten glass in a reduced pressure state and refine it at a low temperature, for example, as described in Japanese Patent Publication No. 51-3.
It is known from Publication No. 3926.

(Problems to be Solved by the Invention) In order to compensate for the drawbacks of conventional glass melting furnaces, the present invention reduces the pressure in the fining section to promote degassing, shortens the length of the fining section, and further The present invention provides a vacuum refining device for molten material that is capable of operating at a lower temperature of molten glass, shortens the time for changing glass types, saves raw materials, and improves energy saving effects.

(Means for Solving the Problems) The present invention includes a first chamber that stores the molten metal by providing a charging port for raw materials or molten metal and a heating source, and a raised bed at the bottom of the furnace in the direction of the furnace +i to direct the molten metal. It consists of a second chamber with an outlet to enable depressurization.A gas seal wall is installed horizontally on the furnace ceiling to completely isolate the first and second chambers, and the bottom of the furnace is electrically connected to connect the first chamber to the second chamber. The feature is that the molten metal flows in two chambers and the layer thickness of the molten metal on the raised bed is controlled.

An example in which the present invention is applied to glass melting and refining will be described below.

In the apparatus of the present invention, the glass raw material charged from the raw material charging port of the glass raw material hopper 1 is melted in a first chamber (hereinafter referred to as a melting section) 5, and the melt becomes a lath 2.

Three combustion burners 4 are installed on each side wall of the melting section. The entire burner area of this combustion burner can be changed depending on the amount of glass melted.

A second chamber (hereinafter referred to as the clarification section) 8 of the apparatus of the present invention is separated from the melting section 3 by a gas seal wall 7 that extends horizontally over the furnace ceiling 15. As will be described later, the gas seal wall 7 is designed so that the melting section 6 and the refining section 8 share a furnace bottom 16 and are electrically connected to each other.

The combustion burners in the melting section 6 are alternately fired, and the heat exchanger 5 recovers the exhaust heat. The outlet air temperature of this heat exchanger is 300-400℃, whereas the conventional melting furnace has a high temperature of about 1000℃.
A low temperature of 00°C is sufficient. Since the heat exchanger can have a simple structure, the equipment cost can be reduced by about 1/10 compared to conventional ones.

The reason why this low-temperature air blowing is possible is that the refining section 8 is depressurized to increase the degassing rate. The glass is dissolved to 80% in the melting section 3, and most of the gas in the glass is degassed here. However, the temperature atmosphere in the melting section is lower than the conventional conditions due to the action of the clarification section 3, which is the decompression equipment in the next process. 100-20
Q℃ can be lowered.

For this reason, even if the gas in the glass does not escape sufficiently in the melting section and remains in the fining section, it can be immediately degassed by reducing the pressure and there is no problem. That is, in the present invention, glass is melted in a melting section in a glass melting furnace, the clarification section for degassing is reduced in pressure, the melting section and the gas atmosphere are completely isolated, and the glass phase flows continuously through the melting section and the clarification section.

Therefore, compared to the conventional melting furnace, the fuel oil consumption of the melting furnace according to the present invention can be reduced by 60 to 70 tons per glass product. The glass in the melting section passes under the gas seal wall 7 and is guided to the fining section 8 using the reduced pressure in the fining section and the mechanical stretching of the product glass as a driving force. The combustion gas in the melting section is sealed here with the clarification section. In order to prevent combustion gas from the melting section from flowing into the clarification section, the gas sealing depth 6 of the molten glass is set to a maximum value considering the maximum vacuum pressure in the clarification section. Gas seal wall 7
Inside the water-cooled pipe, there is a gas seal wall that controls the temperature according to the amount of water so that it does not exceed a certain temperature. Therefore, only the melting section is structurally the same as the conventional furnace, but the equipment scale can be reduced if the production volume and combustion temperature are the same. A combustion burner 9 is also provided in the clarification section, which is used to raise the temperature of the furnace wall at 9 hours of startup, and is stopped in a steady state.

Inside the fining section 8, a raised bed 10 is installed on the furnace bottom 16 in the width direction of the furnace. Therefore, the layer thickness of the glass under reduced pressure can be controlled. That is, in the raised bed 10, the glass flow is held up due to the reduced pressure in the fining section, and plays an important role in determining the glass layer thickness 11 in the degassing zone. The main factors that affect the degassing rate are temperature, degree of vacuum, and layer thickness.Of these, temperature and degree of vacuum can be easily changed during operation, but the layer thickness cannot exceed a certain level. The height of the raised floor is determined and controlled in terms of equipment.

Moreover, the layer thickness can also be controlled operationally.

The depressurization in the clarification section is carried out by a vacuum pump through three decompression ports 12 and 16 in two stages, upper and lower, and the layer thickness 11 is controlled.

By this operation, it is possible to operate so that the layer thickness 11 does not exceed 30 crn. Due to this raised bed and two upper and lower stages of pressure reduction, the length of the conventional clarification section can be shortened to approximately 173 mm, and the temperature of the gas atmosphere in the melting tank and clarification tank section can be lowered by the pressure reduction effect. In addition, the wear and tear on the refractories can be reduced, so you can save on refractory bricks compared to traditional furnaces.

The outlet of the fining section is sealed by the partition wall 14 only when the furnace starts up, and when the glass is melted and filled into the fining section, the partition wall 14 is sealed.
Remove the glass and let it flow to the next glass process. Partition walls will be removed using a mobile crane. As the outflow mechanism, it is preferable to use a method of mechanically pulling the glass, such as a pinch roll, as in conventional glass manufacturing.

In the present invention, if the inside of the clarification tank is reduced to a pressure of about 200 m of mercury, the average temperature of the molten glass will be 1260°C, which is sufficient.1 This can be lowered by 100 to 200°C compared to conventional methods, and the life of the bricks will be extended. The reduction in technology, stingray saving and effectiveness, and reduction in equipment scale are remarkable.

Although the present invention has been mainly explained above regarding glass melting and vacuum operation, the present invention is not limited thereto, and can of course be applied to melting and refining of iron or non-ferrous metals or vacuum degassing refining. However, it does not depart from the scope of the present invention.

(Effects of the Invention) As described above in detail, the present invention obtains molten metal in the first chamber and maintains it under reduced pressure in the second chamber.

? Since the layer thickness of the molten metal on the raised bed provided in chamber 52 is controlled to a desired value for degassing, the equipment can be made compact and operating costs can be significantly reduced, which has great industrial effects.

[Brief explanation of drawings]

FIG. 1 is a plan view of the present invention, and FIG. 2 is a side view of FIG. 1.

Claims (1)

[Claims] It consists of a first chamber that stores the molten metal with a charging port for raw materials or molten metal and a heating source, and a second chamber that has a raised bed installed at the bottom of the furnace in the direction of the width of the furnace and an outlet for the molten metal so that it can be depressurized. , a gas seal wall is installed horizontally on the furnace ceiling to isolate the first and second chambers,
Conducting the bottom of the furnace to obtain a flow of molten metal from the first chamber to the second chamber,
A vacuum refining device for molten metal that controls the layer thickness of molten metal on a raised bed.