JPS58164732A - Air permeable solid wall in continuous heat treatment furnace - Google Patents

Abstract

PURPOSE:To provide a titled solid wall which reduces initial costs, improves heat transfer efficiency and is safe against the rupture of the plate, etc., by disposing solid walls in frames formed of heat resistant supporting members and protectors in a heat treatment furnace, and disposing burners between two rows of the solid walls. CONSTITUTION:Two rows of air permeable solid walls 4 facing a strip material 1 forming plural passes with hearth rolls 17 are disposed within the frames formed of horizontal supporting pipes 2 having refractory materials 13 and protectors 3 provided at prescribed intervals in the transverse direction of the furnace in a vertical type continuous heat treatment furnace of a direct heating type without oxidation wherein said walls 4 are provided and the material 1 is heat-treated efficiently with the uniform gaseous flow 15 in the arrow direction formed of the combustion gases generated with heaters 18. Combustion pipes 8 connected to combustion mehanisms or air pipes 10 for secondary combustion, or heat exchangers 7 for preheating, etc. are provided between two rows of the adjacent walls 4, whereby the efficiency of the furnace is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion device in a direct-fire non-oxidation heating type vertical continuous heat treatment furnace (hereinafter referred to as NOF, including a preheating furnace) or a permeable solid-walled air pipe with a built-in air pipe for secondary combustion. It's about structure.

Generally, in a continuous heat treatment furnace for strip material, as shown in Fig. 1, the strip material 1 is 7% in the furnace - throttle 1
A plurality of passes are formed through 7 and heated by a heating device 18 . The strip material I is heated from 250 to 300 C to 500 to 700 C using combustion gas in a weakly oxidizing atmosphere with an air ratio of 0.87 to 0.98 in order to make the oxide film as thin as possible. Therefore,
Combustion equipment or air injection for secondary combustion is used to convert unburned gas into thermally engineered wood in the preheating furnace, but in the low temperature range of the strip due to free 〇 caused by incomplete combustion of unburned gas. There is a problem of oxidation.

In place of the furnace wall 14 of the conventional furnace shown in Fig. 1C Fig. 2 5 = A uniform gas flow 15 indicated by the arrow toward the downstream side is ensured on the permeable solid surface on the upstream side by flowing the baking gas.

By promoting the combustion of the air and unburned gas blown in from between the two rows of the permeable solid walls 4 in the permeable solid wall 4 on the downstream side, and eliminating the free 02, the free 02 is added to the strip.
It is possible to prevent the formation of an oxide film by preventing contact between the two. It is also possible to incorporate a heat exchanger 7 for combustion air in place of the air pipe 10.

On the other hand, in a vertical continuous heat treatment furnace for strip material, the strip material may break, and the broken strip material may damage the air-permeable solid. However, due to its nature, the breathable solid does not have the strength to withstand external forces such as plate breakage, and the structure of installing the breathable solid in the furnace poses a problem.

In view of the above points, the present invention provides a direct-fired non-oxidizing furnace with the following objectives: ■ To increase heat transfer efficiency and save energy; ■ NOF
In order to reduce equipment costs by shortening the length of the equipment due to changes in the heat transfer surface configuration, it is possible to place more than 65% of the gas passage area within a permeable solid wall, kNOF. The purpose of this invention is to effectively support the air-permeable solid wall and to obtain a structure of the air-permeable solid wall that has high strength against external forces such as breakage due to summer trips. Further, the present invention seeks to provide a breathable solid wall structure that can suppress the formation of oxide film on the strip.

The feature of the present invention is a split type two-row breathable solid;
It consists of a support pipe, a protector, a breathable solid support frame, etc.

Note that the breathable solid here refers to a porous material that has air permeability and a suitable pressure drop.Metallic materials include foamed metals, sintered metals, etc., and refractory materials include porous ceramics, porous SiC, and alumina. There are things such as ball joints.

In general, this type of breathable solid is porous, so the heat transfer phenomenon between the breathable solid and the passing gas is approximately similar to heat transfer in a packed bed of granular material, and the equivalent diameter of the breathable solid is 0.1 ~11■
If the temperature is about 100 kcal/w?hc, a large convective heat transfer coefficient of 1 O” to 10 kcal/w?hc can be obtained, making it breathable;
The surface temperature of the solid is almost instantaneously close to the gas temperature (up to i'')
It is said to be heated (or cooled) and has the following characteristics:
) An embodiment of the present invention will be explained below with reference to the drawings.

The present invention provides a vertical continuous heat treatment furnace in which two or more rows of air-permeable facepiece walls are arranged between the strip materials, making up at least 65% of the gas passage area, and between the two rows of air-permeable solids. This relates to a support structure for a breathable solid wall 4 incorporating a heat exchanger 7, a secondary combustion air blowing pipe 10, or a combustion pipe 9, a breathable solid wall 4 support pipe protector 31, and a breathable solid support frame. It is characterized by being composed of 6 mag.

Heat-resistant support members 2 (hereinafter referred to as support pipes) are installed horizontally in the height direction to support the breathable solid wall 4 and to propagate external forces such as plate breakage to the furnace shell hardware 16, which is a strength member of the furnace body. do. This pipe 2 has the bending rigidity against its own weight of the refractory material 13 lined on the outer surface, and the strip material 1
It has sufficient strength under high-temperature atmospheric conditions to withstand external forces caused by breakage of the furnace, and is supported by furnace shell hardware 16, and its outer surface is lined with refractory material 13. Since the support pipe 2 is small in diameter and requires sufficient impact strength, a metal pipe is used, and if necessary, it is cooled by flowing air through the inner surface. Note that combustion air can be used as this cooling air.

In order to prevent the broken strip material from damaging the breathable solid wall 4, a protector 3 for protecting the breathable solid material is provided so as to be able to deal with the breakage of the strip material l of any width.

The protector can be provided with grooves to support the air permeable solid wall 4 and can also serve as a support frame. Further, a frame 6 is provided for supporting the breathable solid wall 4 with a support pipe. Each frame 6 has a groove with a slope on one side so that it can be easily replaced when the air permeable solid wall 4 is damaged.

Further, the frame 6 and the breathable solid wall 4 are designed so that the impact load at the time of plate breakage does not act on the breathable solid wall 4 through the support pipe 2.
In order to prevent damage to the breathable solid wall 4 due to the thermal deformation difference between the
A cushioning material 5 is inserted between the breathable solid wall 4 and the frame 6. In addition, a frame 6 is provided at the connection portion between the vertically divided breathable solid walls 4 and the breathable solid walls 4 to prevent mutual influence during thermal deformation.
Enter -1.

The device built between the two rows of air permeable solid walls 40 includes a combustion pipe 9 connected to a combustion mechanism, as shown in FIGS. 3 and 4.
, the air pipe 10 for secondary combustion, or the heat exchanger 7 for preheating, and has a structure in which it is attached by penetrating the protector 3. FIG. 4(a) shows an example in which a secondary combustion air pipe 10 or a heat exchanger 7 is installed, and FIG. 4(b) shows an example in which a combustion pipe 9 is installed. Furthermore, a plurality of holes are drilled at regular intervals in the combustion tube 9, etc., and combustion gas or air is blown into the furnace through these holes to promote combustion of unburned gas and reduce free 02.

For example, in a direct-fired non-oxidation heating type vertical continuous heat treatment furnace, energy can be saved by increasing the heat transfer efficiency of the direct-fired non-oxidation furnace, equipment costs can be reduced by changing the heat transfer surface configuration, and combustion gas can be freed. In order to reduce this, two or more rows of permeable solid walls are arranged horizontally in the furnace, and combustion equipment, etc. are built in between the rows, and protectors against plate breakage, support pipes, and support frames are installed. The effect of attaching and installing an air permeable solid wall to a structure, etc., is remarkable because it not only protects the air permeable solid wall but also enables the construction of a small air permeable wall.

[Brief explanation of drawings]

FIG. 1 shows the layout of a conventional direct-fired non-oxidizing furnace, and FIG. 2 shows the layout of a direct-fired non-oxidizing furnace incorporating the present permeable solid wall. Figure 3&), 6:I) is a vertical cross-sectional view showing the support structure of the air permeable solid wall, and Figure 4 (A), ←) is a cross-sectional view showing aspects such as combustion tubes between the air permeable solid walls. It is. l... Strip material, 2... Support pipe,
3...Protector, 4...Breathable solid wall, 6
...Support frame, 7. Heat exchanger, 9.. - Combustion tube, 10.. Air blowing pipe Tomoyuki Yabuki (and one other person), patent attorney representing the patent applicant, ) (B)

Claims (1)

[Claims] In a continuous heat treatment furnace where metal strip material forms multiple passes through rolls, two or more rows of heat-resistant support members are installed horizontally in parallel between the strip materials or between the strip materials and the furnace wall. Further, protectors are arranged at predetermined intervals in the height direction of the two furnaces, and protectors are disposed on each of the heat-resistant support members at predetermined intervals in the furnace width direction, and the heat-resistant support members and the protectors are arranged at predetermined intervals in the furnace width direction. A ventilated solid wall in a continuous heat treatment furnace, characterized in that a ventilated solid wall is disposed within each frame formed by the above, and a combustion device is disposed between the plurality of rows of ventilated solid walls.