JPH0227302Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a molten metal heating device that heats molten metal stored in a bath by heating an immersion cylinder in the molten metal.

[Prior art and its problems] Conventionally, such a molten metal heating device includes a burner installed in an immersion cylinder, a combustion flame of the burner colliding with the inner bottom of the immersion cylinder, and further a connection between the immersion cylinder and the burner. It is well known that the immersion tube is heated by turning the flame upward from the gap.

However, according to the molten metal heating device, the combustion flame intensively collides with the inner bottom of the immersion cylinder, causing the inner bottom to locally overheat. This has resulted in a disadvantage that a difference in thermal expansion occurs at the bottom or side wall of the dipping tube, causing cracks and making the dipping tube unusable.

For this reason, for example, in the device described in Japanese Patent Application Laid-open No. 61-272517, a cap made of ceramic is provided at the tip of the outer tube of the radiant tube corresponding to the immersion tube, facing the tip of the inner tube. This prevents local overheating and cracks at the tip of the outer tube.

However, the tip of the outer tube has a corner section where the inner bottom and the inner circumferential wall connect at right angles, and the outer diameter of the planar circular cap that is fitted into the tip is approximately the same as the inner diameter of the planar circular tip. Since they are identical, the cap fits into the inner bottom of the distal end of the outer tube without any gaps. For this reason, all of the hot air impinges on the cap, so no hot air is blown onto the tip of the outer tube, and the radiant tube itself is heated unevenly, which is a problem.

Furthermore, there is a difference in thermal expansion between the cap, which is placed inside the outer tube and is exposed to hot air directly, and the outer tube, which is in contact with a lower temperature, even if they are made of the same material. This also has the disadvantage that cracks may occur at the tip of the outer tube, resulting in a shortened service life.

[Purpose and structure of the invention] The purpose of the invention is to solve the above-mentioned problems, and involves immersing a bottomed cylindrical ceramic immersion tube into molten metal stored in a hot water tank, and In a molten metal heating device in which a burner is provided in a cylinder and the combustion flame of the burner collides with the inner bottom of the immersion cylinder and is bent upward, a corner where the inner bottom of the immersion cylinder and the inner circumferential wall are connected A heat-resistant protector whose corners are formed into arcuate surfaces or sloped surfaces and whose planes are formed into polygonal shapes is placed in the immersion cylinder so that its corners are supported by the arcuate surfaces or sloped surfaces. It is composed of

[Operation] After most of the combustion flame collides with the heat-resistant protector, it rises along the inner circumferential wall of the immersion cylinder and heats the side wall. At the same time, a portion of the combustion flame passes through the gap between the polygonal protector and the arcuate or sloping corner of the immersion tube, and also heats the bottom of the immersion tube. The heated protector also radiates and heats the bottom of the immersion tube. As a result, the bottom and side walls of the immersion cylinder are heated uniformly, thereby preventing local differences in thermal expansion from occurring.

Even if the heat-resistant protector is thermally expanded by the flame, it will not cause cracks on the side wall of the immersion tube because the protector has a polygonal shape and is arranged in an arcuate corner or on a slope so that it can expand and contract freely.

[Example] Next, an embodiment of the present invention will be described with reference to the drawings.

Reference numeral 1 denotes a cylindrical ceramic immersion tube with a bottom, the tip of which is suspended and immersed in molten metal 3 stored in a hot water tank 2. The immersion tube 1 has an intermediate upper support portion 1a fixed to the upper edge of the bath 2.

A burner 4 is disposed at the center of the interior of the immersion cylinder 1, and its tip part hangs down near the inner bottom 12. 6 is the burner 4
7 is a combustion pipe leading to a gas source (not shown); gas pipes 8a and 8b are air passages leading to an air pipe (not shown); 9 is an ignition source and a flame detector. 10
is a flow path for exhaust gas of combustion gas that communicates with the inside of the immersion tube 1.

Reference numeral 11 denotes an arcuate surface of a corner portion 14 where the inner bottom 12 and inner circumferential wall 13 of the immersion tube 1 are connected, and 15 is a regular square plane on which the corner portion 15a is supported by the arcuate surface 11. It is a heat-resistant protector made of shaped ceramics. The protector 15 and the inner bottom 12
As shown in FIG.
It is arranged so that it can expand and contract at will.

As shown by the arrow in FIG.
It collides with the protector 15 and locally overheats that part. Thereafter, a portion of the flame passes through the gap 16 between the protector 15 and the inner bottom 12 and heats the bottom 17 of the lower surface of the protector 15 appropriately. Most of the flame is blocked by the protector 15, turns upward, passes through the gap between the combustion tube 6 and the inner peripheral wall 13 of the immersion cylinder 1 as shown by the arrow, and rises while heating the side wall 18, and is combined with combustion gas. The gas is then discharged to the outside from the exhaust gas pipe 10. At this time, the bottom 17 of the immersion tube 1
The temperature of the molten metal 3 and the temperature of the side wall 18 are maintained substantially the same, and the molten metal 3 around the immersion tube 1 is heated evenly and substantially uniformly.

4 to 6 show a protector 15 according to another embodiment of the present invention. In FIG. 4, the protector 15 has a regular rectangular plane and has protrusions 19 at the center and side edges. Form. Due to this shape, the combustion flame that collides with the center circulates upward along a symmetrical curved shape,
The side wall 18 of the immersion cylinder 1 can be heated more uniformly.

In FIG. 5, a vertical hole 20 is formed in the square protector 15, and an appropriate amount of the flame that impinges on the surface of the protector 15 is allowed to pass therethrough, thereby heating the bottom portion 17 to an appropriate temperature.

FIG. 6 shows a vertical hole 2 in the peripheral wall of a protector 15 formed in the shape of a shallow dish with a square plane and a cross section.
A zero or horizontal hole 21 is opened to facilitate the upward circulation of the flame, and a portion of the flame passes through to uniformly heat the bottom 17 and side wall 18 of the immersion cylinder 1.

Although the above embodiments have all been described as having a regular rectangular shape in plan view, the shape may be an equilateral triangle or a polygon having a square shape or more. Alternatively, it may have a polygonal shape such as a star shape or a gear shape, and in short, the corner portions may be supported by an arcuate surface. Furthermore, the shape of the corners of the immersion cylinder may be formed into a sloped shape instead of an arcuate shape.

[Effect of idea]

As explained in the embodiments above, according to the present invention, the combustion flame injected from the burner uniformly heats the bottom and side walls of the immersion tube, so the molten metal can be heated evenly. This is useful because it can prevent the occurrence of cracks at the bottom and extend the life of the dipping tube.

[Brief explanation of the drawing]

The drawing shows one embodiment of the present invention.
The figure is a cross-sectional side view of the molten metal heating device, Figure 2 is an enlarged cross-sectional view taken along line A-A, and Figure 3 is B-B of Figure 2.
The line sectional views and FIGS. 4 to 6 are sectional views showing the respective protectors arranged on the inner bottom. 1... Immersion cylinder, 2... Water tank, 3... Molten metal,
4... Burner, 11... Arc-shaped surface, 12... Inner bottom, 13... Inner peripheral wall, 14... Corner portion, 15...
Protector, 15a...corner, 17...bottom, 1
8...Side wall.

Claims (1)

[Scope of utility model registration request] A bottomed cylindrical ceramic immersion cylinder is immersed in molten metal stored in a hot water tank, a burner is installed inside the immersion cylinder, and the combustion flame of the burner collides with the inner bottom of the immersion cylinder and moves upward. In the molten metal heating device that is folded back, the corner portion where the inner bottom and the inner circumferential wall of the immersion cylinder are connected is formed into an arcuate surface or an inclined surface, and a heat-resistant protector whose plane is formed in a polygonal shape is attached to the corner portion where the inner bottom and the inner circumferential wall are connected. A molten metal heating device characterized in that the molten metal heating device is disposed in an immersion cylinder such that a corner portion is supported by the arcuate surface or slope.