JPH0711169Y2 - Heating equipment for alloying furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a heating device for an alloying furnace for alloying a plated portion of a steel strip having a surface plated.

[Conventional technology]

FIG. 7 shows a sectional view of a conventional alloying furnace. Figure 7 (a)
Is a sectional view, FIG. 7 (b) is BB in FIG. 7 (a).
FIG. This apparatus is an apparatus used for forming an alloyed layer of zinc and iron on the surface of a steel sheet. In the figure, 1 is a strip, 2 is a zinc plating tank for immersing the strip and plating the surface thereof, 3 is a heating device for heating the plated strip, and 4 is a heat insulator for the strip that has passed through the heating device. It is a heat retention device. Reference numeral 5 denotes an open flame burner such as a cup burner arranged on the furnace wall for radiatively heating the strip 1 in the heating device 3 described above, and the arrow in the figure indicates the moving direction of the strip. The part consisting of the heating device 3 and the heat retaining device 4 described above is the part of the alloying furnace called the galvannealing device, and the plating tank 2
The plated strip in 1 is passed through this device to treat its surface for alloying.

[Problems to be solved by the device]

The in-furnace gas temperature is determined by the heat load such as the combustion load of the direct-burning burner 5, the infiltration gas from the outside of the furnace, the heat radiation amount to the outside of the furnace, and the heating amount to the strip. When the temperature becomes higher, the temperature of the strip edge portion becomes too high due to the effect of gas radiation, and the temperature in the width direction of the strip becomes non-uniform, so that the combustion load of the open flame burner cannot be arbitrarily increased.

Further, since the appropriate furnace gas temperature depends on the emissivity of the strip to be heated, it is necessary to control the furnace temperature according to the surface condition of the strip. For example, the higher the strip emissivity, the lower the furnace gas temperature must be. In this case, if the combustion load of the direct-burning burner is lowered in order to lower the temperature of the gas in the furnace, high-temperature combustion gas flows unevenly in the furnace, which causes inconveniences such as temperature unevenness in the width direction of the strip. The combustion load of an open flame burner cannot be arbitrarily lowered.

For the above reasons, it is difficult to uniformly heat the strips having various emissivities in the width direction only by the combustion load of the direct-burning burner at an appropriate furnace temperature.

The present invention intends to maintain the gas temperature in the furnace appropriately by controlling the gas temperature in the furnace independently of the combustion load of the direct-burning burner, and to realize a uniform gas temperature distribution in the width direction of the strip. It is a thing.

[Means for Solving the Problems]

The present invention has solved the above problems and relates to the following devices.

(1) An alloying furnace comprising a heating device equipped with a direct-burning burner and a heat-retaining device provided in contact with the upper part of the heating device. The steel strip that has passed through the plating tank is continuously passed through to alloy the plating part. In the above heating device, the heating of the alloying furnace is provided with means for adjusting the temperature of the combustion gas extracted from the inside of the heating device, and means for returning the gas to the inside of the heating device again. apparatus.

(2) A means for spraying the recirculated combustion gas onto the surface of the steel strip through nozzles arranged in the width direction of the steel strip before the front burner or before and after the direct burner. A heating device for an alloying furnace according to item (1).

[Action]

Regarding the means of the above item (1), by extracting the combustion gas from the inside of the heating device, adjusting the temperature to an appropriate temperature and returning the same to the inside of the heating device, independent of the combustion load of the direct-fired burner, The gas temperature can be controlled.

With regard to the means of (2) above, the combustion gas to be recirculated is sprayed on the surface of the steel strip through a nozzle arranged in the width direction of the steel strip in front of or before and after the direct burner, The surface of the strip is covered with a flowing combustion gas, which avoids impingement heating of the flame of an open flame burner, which results in a uniform temperature across the width of the steel strip.

〔Example〕

FIG. 1 shows a sectional view of a first embodiment of the invention according to claim (1). The parts denoted by reference numerals 1 to 5 have the same functions as in the case of the conventional technique, and therefore the description thereof will be omitted. In the figure, 6 is a combustion gas extraction pipe for extracting a part of combustion gas from the inside of the heating device 3, 7 is a combustion gas extraction amount control valve provided on the pipe, and 8 is air sucking room temperature air from outside the device. Air intake pipe, 9 is an air intake adjusting valve provided on the pipe, 10 is a booster fan provided at a portion where the combustion gas extraction pipe 6 and the air intake pipe 8 merge, and 11 is the booster fan 10. A hot air supply pipe connected to the outlet to supply hot air into the furnace.

The parts denoted by reference numerals 6 to 11 constitute a hot air supply device.

With the above-mentioned device, a part of the combustion gas is sucked from the extraction pipe 6 by the fan 10 and, on the other hand, is mixed with the room temperature air sucked from the air suction pipe 8 to be adjusted to an appropriate temperature, and from the hot air supply pipe 11 Reflux is supplied to the furnace. The temperature of the supplied gas is controlled by operating the openings of valves 7 and 9.

As described above, in the apparatus according to the first embodiment, the temperature of the atmosphere inside the furnace can be controlled independently of the combustion load of the direct-burning burner by adjusting the gas temperature and returning the gas.

FIG. 2 shows a sectional view of a second embodiment of the invention according to claim (2). 2 (a) is a sectional view, and FIG. 2 (b) is a second view.
It is an AA cross section arrow line view in Drawing (a). In the figure, reference numerals 1 to 11 are parts having the same functions as those in the prior art and the first embodiment, and therefore description thereof will be omitted. In the present embodiment, the combustion gas extraction pipes 6 are provided at two positions on the front surface side and the back surface side of the strip, and accordingly, the hot air supply device has two systems. In each line,
A hot air supply pipe 11 connected to the booster fan 10 branches in three directions. In the figure, 12 is a hot air blowing nozzle provided in front of or in front of the open flame burner in the furnace wall at the tip of each hot air supply pipe 11, and has a shape as shown in the perspective view of FIG. There is. In this embodiment, in order to blow hot air evenly in the width direction on the surface of the strip through the nozzle 12, the nozzle 12 has a long slit shape in the width direction of the strip, and is formed on each side of the strip. Three are provided. The number of nozzles is not limited. The parts denoted by reference numerals 6 to 12 form a hot air supply device.

As described above, in the second embodiment, the temperature of the gas in the furnace can be controlled independently of the operation of the combustion load of the direct burner, and the surface of the strip is covered with the flowing combustion gas, whereby the flame of the direct burner is burned. Impact heating is avoided, and as a result, the temperature distribution in the width direction of the steel strip can be made uniform.

FIG. 4 is a perspective view of the nozzle in the third embodiment.
This nozzle is a nozzle having the same effect as the nozzle shown in FIG. 3, and is used in place of the nozzle shown in FIG. 3 in the hot air supply device shown in FIG. A plurality of circular hole nozzles 13 are provided adjacent to each other in a row in the width direction of the strip. In short, the shape of the hot air blowing nozzle may be any shape as long as uniform heating is performed in the width direction of the strip. In this embodiment, the parts other than the above are the same as those in the second embodiment, and the description thereof will be omitted.

FIG. 5 is a perspective view of the nozzle in the fourth embodiment.
This nozzle is also used in the hot air supply apparatus shown in FIG. 2 instead of the nozzle shown in FIG. This nozzle is made of refractory brick, plastic refractory material, castable refractory material, etc. to make a plenum chamber independent of the furnace body.
It is a nozzle that is installed in the furnace body in the same way as when installing an open flame burner in the furnace body, and in the case of damage, it is easy to repair and replace. In the figure, 14 is a plenum chamber,
Reference numeral 15 is a flange for attachment to the furnace body. The present embodiment is the same as the second embodiment except for the structure of the nozzle described above, and the description thereof is omitted.

FIG. 6 is a sectional view of the nozzle in the fifth embodiment.
This nozzle is also used in the hot air supply apparatus shown in FIG. 2 instead of the nozzle shown in FIG. This nozzle is the fifth
Although it has almost the same structure as that shown in the figure and has a plenum chamber 14 and is independent of the furnace body, when hot air blows from the plenum chamber 14, refractory powder is simultaneously ejected. Therefore, the inner surface of the plenum chamber is further covered with heat-resistant steel as shown in FIG. In the figure, 16 is a heat-resistant steel lining. The present embodiment is the same as the second embodiment except for the structure of the nozzle described above, and the description thereof is omitted.

[Effect of device]

The heating apparatus for the alloying furnace of the present invention is provided with means for adjusting the temperature of the combustion gas extracted from the inside of the heating apparatus and means for returning the gas to the inside of the heating apparatus again. Without having to operate the combustion load of the fire burner
The gas temperature in the heating device can be controlled.

Further, since the combustion gas to be recirculated is sprayed onto the surface of the steel strip through nozzles arranged in the width direction of the steel strip before the front burner or before and after the direct burner, the width of the steel strip is provided. The heating temperature in the direction can be made uniform.

[Brief description of drawings]

1 is a sectional view of a first embodiment of the present invention, FIG. 2 is a sectional view of a second embodiment of the present invention, and FIG. 3 is a perspective view of a nozzle portion of the second embodiment. FIG. 6 is a perspective view of the nozzle portion of the third embodiment, FIG. 5 is a perspective view of the nozzle portion of the fourth embodiment, and FIG.
FIG. 7 is a sectional view of the nozzle portion of the fifth embodiment, and FIG. 7 is a sectional view of the prior art. 1 ... Strip, 2 ... Galvanizing tank, 3 ... Heating device, 4 ... Heat retention device, 5 ... Direct burner, 6 ... Combustion gas extraction pipe, 7 ... Combustion gas extraction amount control valve, 8 ...... Air intake pipe, 9 ...... Air intake amount control valve, 10 ...... Pressurizing fan, 11 ...... Hot air supply pipe, 12 ...... Hot air blowing nozzle, 13
…… Circular hole nozzle, 14 …… Plenum chamber, 15 …… Mounting flange, 16 …… Heat resistant steel lining.

Front page continuation (72) Inventor Yonosuke Hoshi 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Toshio Kato 4-6 Kannon-shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture No.22 Mitsubishi Heavy Industries, Ltd. Hiroshima Research Institute (72) Inventor Junkichi Yoneda 4-6-22 Kannon-Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute (72) Yuida Iida Mizushima Kurashiki, Okayama Prefecture Kawasaki Dori 1-chome (without street number) Inside Kawashima Steel Co., Ltd. Mizushima Steel Works (72) Inventor Harumi Shigemoto Mizushima Kurashiki City, Okayama Prefecture Kawashima Street 1-chome (without street number) Kawasaki Steel Co., Ltd. Mizushima Steel Works (56) References Japanese Patent Publication Sho 50-3980 (JP, B1)

Claims (2)

[Scope of utility model registration request] 1. An alloying system comprising a heating device equipped with an open flame burner and a heat retaining device provided in contact with the upper part of the heating device. In the above heating device of the furnace, an alloying furnace comprising means for adjusting the temperature of the combustion gas extracted from the inside of the heating device and means for returning the gas to the inside of the heating device again. Heating device. 2. A means for spraying the recirculated combustion gas onto the surface of the steel strip through nozzles arranged in the width direction of the steel strip before the front burner or before and after the direct burner. The heating device for the alloying furnace according to claim 1.