JPS60149757A - Continuous type hot dipping installation - Google Patents

Abstract

PURPOSE:To perform a plating treatment with decreased energy and a simple installation by supplying the high-temp. and high-pressure air to a gas throttling device for controlling the coating amt. of plating through a heat exchanger which subjects the waste combustion gas from a heat treating furnace to a heat exchange from an ordinary temp. pressure increasing device. CONSTITUTION:A strip S is heat-treated in a heat-treating furnace 1 and is then dipped in a metal hot dipping bath 2 and right after the strip emerges from the bath 2, a gas is ejected thereto from a gas throttling device 3 to control the coating weight of plating. An ordinary temp. pressure increasing device 4 for air and a heat exchanger 5 are provided there so that the air from the device 4 is subjected to a heat exchange with the waste combustion gas from the furnace 1 in the heat exchanger 5. The air increased in pressure by the device 4 and heated by the heat exchanger 5 is conducted through a supply piping 6 to the device 3 and is sprayed to the surface of the strip S from the nozzle 31 of the device 3. The heat of the waste combustion gas of the furnace 1 is thus effectively utilized and the pressure is increased without the need for a special device such as pressure increasing device for high temp. or the like and without decreasing the volumetric efficiency. The purpose is thus achieved.

Description

[Detailed description of the invention] The present invention relates to continuous hot-dip metal plating equipment.

As shown in Figure 1, a continuous molten metal plating system is known in which a heat treatment furnace (1), a molten metal plating bath (2), and a gas throttling device (3) are sequentially arranged as basic equipment. After the strip (S) is heated in a heat treatment furnace (1), it is immersed in a plating bath (2) and plated. Gas is sprayed from the injection nozzle (31) of the squeezing device (3) to control the amount of plating deposited.In addition, after this series of treatments, post-processing equipment (7) such as pickling and chemical conversion treatment is used. Post-processing is performed at the machine.

By the way, in the above-mentioned gas squeezing device (3), if low-temperature gas is used for injection, depending on the amount of plating deposited, hot water wrinkles (abnormal solidification of the plated surface) may occur, which may affect product quality. Therefore, as shown in Figure 1, a method has been adopted in which high-temperature combustion waste gas from a heat treatment furnace (1) is used as an injection gas. The hot gas pressure booster (11) raises the pressure as it is and supplies it to the gas throttling device (3).However, although this method has the advantage of being able to utilize the waste heat of the heat treatment furnace, A special high-temperature gas pressure booster is indispensable to boost the pressure of the combustion waste gas, and there is also the problem of lowering the volumetric efficiency due to boosting the pressure of the high-temperature gas. It's hard to say.

The present invention was devised in view of the conventional problems described above, and is capable of controlling the amount of plating deposited by efficiently supplying high-temperature gas to a gas throttling device without requiring any special equipment. Therefore, the present invention provides a plating equipment with an air room temperature pressurization device, and a system in which the air from the air room temperature pressurization device and the combustion waste gas from the heat treatment furnace are connected to the plating equipment. and a heat exchanger for heat exchange, and an air supply system for supplying high-temperature and high-pressure air from the room temperature pressurization device to the gas throttling device via the heat exchanger. Basic characteristics.

An embodiment of the present invention shown in FIG. 2 will be described below.

The basic equipment of the continuous molten metal plating equipment shown in Fig. 2 is the same as the conventional equipment shown in Fig. 1, including a heat treatment furnace (1), a molten metal plating bath (2), and a gas pattern plate. Device(
3) are arranged in the order of -C.

In the present invention, in such basic plating equipment, room temperature air is pressurized and then heated using the waste heat of the heat treatment furnace (1), and this high pressure and high temperature air is passed through the gas throttling device (3).
), and for this purpose, an air room temperature pressurization device (4) and air pressurized by this air room temperature external pressure device (4) and combustion waste gas from the heat treatment furnace (1) are provided. A heat exchanger (5) is attached to exchange heat with the air, and the high temperature and high pressure air is passed from the room temperature pressurization device (4) to the heat exchanger (5) to the gas throttling device (3). An air supply pipe (6) to be supplied is provided.

In the map, (3) shows the injection nozzle constituting the gas throttle device, (7) shows the after-treatment device, (8) shows the zinc roll, (9) the haphazard roll, and the acm hathnut roll.

In the equipment of the present invention, (i) the IJ tube (S) is subjected to a heat treatment such as annealing in the heat treatment furnace (1);
Immediately after being immersed in the molten metal plating bath (2) and leaving the plating bath (2), gas is injected onto the surface to control the amount of plating deposited. During the plating process, the air taken from the atmosphere into the air supply pipe (6) is pressurized by the air pressure booster (4) at room temperature, and then the combustion waste gas is discharged from the heat treatment furnace (1). It is heated by the introduced heat exchanger (5), and then sent as it is to the gas throttling device (3), where it is sprayed onto the strip surface from the spray nozzle (31). Generally heat treatment furnace (1)
The combustion gas from the heat exchanger (5) has a temperature of about 500°C, and the air supplied to the gas throttling device (3) has a temperature of about 500°C.
Heat exchange is performed within the limit of x400℃. With the equipment of the present invention, it is possible not only to effectively utilize the waste heat of the heat treatment furnace (1) to obtain high-temperature gas for the gas throttling device (3), but also to increase the pressure of air at room temperature. Because of this structure, there is no need for a special pressure booster for high temperatures as in the past, and since the air is boosted at room temperature, the volumetric efficiency can be increased (efficient pressure boosting can be performed without reducing the volumetric efficiency). can.

In addition, in conventional systems that use combustion waste gas directly as the injection gas, a large amount of moisture in the waste gas condenses while the booster is inactive, creating oxidized scale, which causes clogging of the injection nozzle, resulting in uniform throttling. However, since the present invention is based on the premise of using clean air, such problems can be avoided.

According to the present invention described above, it is possible not only to effectively utilize the heat of the combustion waste gas emitted from the heat treatment furnace, but also to increase the pressure without using special equipment such as a high-temperature booster, and without reducing volumetric efficiency. This method has the advantage of being able to obtain high-temperature, high-pressure gas for a gas throttling device with less energy and simple equipment, and to perform this type of plating process rationally and economically.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a conventional continuous hot-dip metal plating equipment. FIG. 2 is an explanatory diagram showing the continuous hot-dip metal plating equipment of the present invention. In the figure, (1) is a heat treatment furnace, (2) is a plating bath, (
3) is a gas throttling device, (4) is an air room temperature pressurization device, and (5)
) indicates the heat exchanger, (6 indicates the air supply piping. Patent issued by Nippon Steel Tube Co., Ltd. Inventor: Hamaguchi, Ito, Department: Tadashi Ishizono, Patent attorney, Yoshihara, Miyoshi) Hiroko Yoshihara, Attorney at Law, Takahashi Department

Claims (1)

[Claims] In continuous molten metal plating equipment, which has a heat treatment furnace, a molten metal plating bath, and a gas throttling device arranged in sequence as basic equipment, an air room temperature pressurization device, and air from the air room temperature pressurization device and air from the heat treatment furnace are provided. A heat exchanger for exchanging heat with the combustion waste gas is attached, and an air supply system is provided for supplying high-temperature and high-pressure air from the room temperature pressurization device to the gas throttling device via the heat exchanger. Continuous hot-dip metal plating equipment featuring the following features: