JP2000121250A - Immersion pipe type liquid heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an immersion pipe of a melting metal holding furnace from being corroded near liquid surface by a simple structure. SOLUTION: A liquid heating device is constructed such that both end suspended sections of a metallic immersion pipe 1 immersed in liquid are out of liquid surface, a burner 2 is fixed to one end of the pipe and combustion discharged gas blown from the burner 2 is discharged out of the other end, wherein a combustion cylinder 3 of the burner 2 is separately arranged from the immersion pipe 1 and inserted from the upper end of the vertical section of the immersion pipe 1 up to a position lower than the liquid surface and at the same time the upper end of a space 4 formed between the combustion cylinder 3 and the immersion pipe 1 is closed or upper end flange sections 3f, 1f of the combustion cylinder 3 and the immersion pipe 1 are provided with a clearance 5 for use in sucking air into a space 4 between the combustion cylinder 3 and the immersion pipe 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submerged liquid heating apparatus suitable for heating and holding molten metals such as zinc and lead.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional liquid heating apparatus of this type, in which vertical portions 1a and 1b at both ends of a metal immersion pipe 1 immersed in a liquid are exposed to the liquid surface. Burner 2 at one end
And the combustion exhaust blown from the burner 2 is discharged from the discharge port 7 at the other end. In this conventional structure, the immersion pipe 1 also serves as the combustion cylinder 3 of the burner 2, and the air-fuel mixture ejected from the burner nozzle 6 in the immersion pipe 1 burns, and the flame directly contacts the inner wall of the immersion pipe 1. In particular, there is a problem that the outer wall surface of the immersion pipe 1 is easily eroded near the liquid surface of the molten metal. Therefore, the immersion pipe 1 used for heating and holding the metal is thicker than the immersion pipe 1 for water heating. Had to be used.

[0003]

FIG. 5 shows another conventional example. In order to prevent erosion of the outer circumference of the immersion tube 1, a cylindrical jacket 8 is provided outside the immersion tube 1. FIG. By blowing cooling air into the jacket 8 with a blower, the erosion near the liquid level is reduced, but the air pipe and the blower are required and the structure becomes complicated, and the upper end of the jacket 8 is welded. There was a problem that the portion 9 was eroded by high heat and was easily broken. The present invention, in view of these problems,
It is an object of the present invention to provide a liquid heating apparatus of this kind in which the outer periphery of the immersion tube 1 is hardly eroded with a very simple structure.

[0004]

As shown in FIGS. 1 and 2, a immersion tube type liquid heating apparatus according to the present invention is characterized in that both ends vertical portions 1a and 1b of a metal immersion tube 1 immersed in a liquid are liquid level. The burner 2 is attached to one end of the liquid heater, and the combustion exhaust blown from the burner 2 is discharged from the other end. In the liquid heating device, the combustion cylinder 3 of the burner 2 is provided separately from the immersion pipe 1. The combustion tube 3 is inserted from the upper end of the vertical portion 1a of the immersion tube 1 to a position lower than the liquid level, and the upper end of the space 4 formed between the combustion tube 3 and the immersion tube 1 is closed. 3) or, as shown in FIG. 3, a gap 5 for sucking air into the space 4 between the combustion tube 3 and the immersion tube 1 is provided in the above-described combustion tube 3 and upper end flange portions 3f, 1f of the immersion tube 1. According to this configuration, the immersion pipe 1 and the combustion cylinder 3 are double near the liquid level. And it has become a structure, the space between them 4
Since high-temperature exhaust gas does not enter the immersion pipe 1, erosion of the immersion pipe 1 near the liquid level of the molten metal can be reduced.

[0005]

1 (a) and 1 (b) are a side view and a plan view, respectively, showing an example in which the present invention is applied to a furnace for holding molten zinc. FIG. 2 is an enlarged sectional view of a main part of the furnace. The vertical part 1a, 1b at both ends of the metal immersion tube 1 in which the horizontal part 1c immersed in the inside is formed in a zigzag shape is exposed to the liquid surface, and the burner 2 is attached downward at the end on the inlet side thereof. The combustion exhaust gas blown from 2 is exhausted to the outside from an exhaust port 5 at the other end through an exhaust duct. Burner 2
4 or 5, the combustion tube 3 of the burner 2 is separate from the submerged tube 1, and the outer diameter of the combustion tube 3 is perpendicular to the inlet side of the submerged tube 1. A position where the length D of the combustion cylinder 3 is smaller than the inner diameter of the portion 1a and the length D of the combustion cylinder 3 is longer than the distance L from one end of the immersion pipe 1 on the inlet side to the liquid level, Is configured to come to. Therefore, when the combustion tube 3 is inserted into the immersion tube 1 and the burner 2 is fixed to the end of the immersion tube 1, the lower end opens into the immersion tube 1 and the upper end extends between the combustion tube 3 and the immersion tube 1. Closed cylindrical space 4
Are formed. Reference numeral 6 denotes a burner nozzle.

In the configuration shown in FIG. 1, the air-fuel mixture ejected from the burner 2 burns in the combustion cylinder 3 or below the combustion cylinder 3, and high-temperature combustion exhaust gas passes through the zigzag immersion pipe 1 and passes through the other end. At this time, part of the combustion exhaust gas enters the space 4 from the lower end of the combustion tube 3. However, since the upper end is closed in the space 4, there is almost no convection. Therefore, the gas in the space 4 is heated from the combustion tube 3 side and at the same time is cooled by the outside air or molten metal through the pipe wall of the immersion tube 1. An intermediate temperature is attained, thereby preventing the immersion tube 1 from being eroded by overheating near the liquid level of the molten metal. Further, in the structure shown in FIG.
Since there is no welded portion 9 as in the above, the durability can be improved accordingly. In this embodiment, the inlet-side vertical portion 1a having a large pipe diameter is close to the bottom of the immersion tube 1 where the temperature of the combustion exhaust gas has cooled to some extent, and the horizontal portion 1 having a predetermined thickness is provided.
c, there is no danger that the welded portion 10 will be eroded or broken by thermal stress, and the diameter of the combustion tube 3 can be the same as that of the conventional immersion tube 1.
Can be made common with the conventional type or for water heating.

FIG. 3 shows another embodiment of the present invention, in which air is sucked into the space 4 between the combustion tube 3 and the dip tube 1 from the upper end of the dip tube 1. In the configuration of FIG. 1, the upper end of the space 4 is closed, and the gas in the space 4 stagnates and considerably rises due to the heat from the combustion tube 3.
Although there is still room for improvement in the erosion prevention effect, FIG.
According to the configuration described above, the kinetic energy of the gas ejected from the burner 2 causes the upper end flange 3
External cold air can be sucked from the gap 5 between the f and 1f, whereby the immersion pipe 1 can be cooled to further enhance the erosion prevention effect near the liquid surface. Gap 5
For example, a ring-shaped spacer having unevenness on the upper surface may be sandwiched between the flanges 1f and 3f, or a concave groove may be provided on the upper surface of the flange 1f of the immersion tube 1.

[0008]

According to the first aspect of the present invention, the combustion tube 3 of the burner 2 and the immersion tube 1 can be formed in a double tube structure near the liquid level by a very simple structure, so that the molten metal There is an advantage that the erosion of the outer peripheral surface of the immersion pipe 1 in the vicinity of the liquid level can be easily prevented, and the welded portion 9 that is weak against thermal stress as shown in FIG. 5 can be eliminated. For example, there is an advantage that cooling air can be introduced into the space 4 between the immersion tube 1 and the combustion tube 3 with a very simple and inexpensive structure without using a blower or the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view (a) and a plan view (b) of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the above.

FIG. 3 is an enlarged sectional view of a main part of another embodiment of the embodiment.

FIG. 4 is a longitudinal sectional view of a main part of a conventional example.

FIG. 5 is a vertical sectional view of a main part of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Submerged pipe 2 Burner 3 Combustion cylinder 4 Space 5 Gap 6 Burner nozzle 7 Outlet 8 Jacket 9 Welded part 10 Welded part

Claims (2)

[Claims] 1. A liquid heating system in which a vertical portion at both ends of a metal immersion pipe immersed in a liquid is exposed to the liquid surface, a burner is attached to one end thereof, and combustion exhaust blown from the burner is discharged from the other end. In the apparatus, the combustion cylinder of the burner is provided separately from the submerged pipe, and the combustion cylinder is inserted from the upper end of the vertical portion of the submerged pipe to a position lower than the liquid level to form between the combustion cylinder and the submerged pipe. Immersion tube type liquid heating device that closes the upper end of a closed space. 2. A liquid heating device in which a vertical portion at both ends of a metal immersion pipe immersed in a liquid is exposed to the liquid surface, a burner is attached to one end thereof, and combustion exhaust blown from the burner is discharged from the other end. In the apparatus, the combustion cylinder of the burner is provided separately from the submerged pipe, the combustion cylinder is inserted from the upper end of the vertical portion of the submerged pipe to a position lower than the liquid level, and the combustion cylinder and the upper end flange of the submerged pipe are connected. An immersion tube type liquid heating device comprising a gap between the combustion tube and the immersion tube for sucking air into the space.