A device for humidifying in a galvanizing furnace

Abstract

The utility model relates to a kind of galvanizing furnace inner humidifying device, including humidifying chamber, the strip steel entrance and strip steel outlet of humidifying chamber both sides are equipped with sealing roller;Temperature sensor for measuring strip steel temperature is equipped on the outside of sealing roller;At least two groups of gas collector parallel to strip steel are equipped in humidifying chamber, and gas collector is equipped with gas outlet hole;Gas collector is connected dry nitrogen pipe and wet nitrogen pipe respectively by gas inlet pipe, and control valve is equipped on dry nitrogen pipe and wet nitrogen pipe;Humidification water tank or heating humidifying device is equipped on wet nitrogen pipe;Exhaust valve and exhaust duct are equipped on the upper and lower sides of humidifying chamber, and gas pressure sensor is arranged in humidifying chamber.The utility model realizes the humidification control of strip steel by setting humidifying chamber on the strip steel of specified temperature range and inputting humidity controllable nitrogen, to realize the controllable oxidation of product, to inhibit the uncontrollable oxidation of other elements by the control of oxide film, to realize the effective control of surface adhesion.

Description

Technical Field

[0001] This utility model belongs to the technical field of auxiliary devices for hot-dip galvanizing annealing furnaces, and specifically relates to a humidification device inside a galvanizing furnace. Background Technology

[0002] In the hot-dip galvanizing process of steel strip, ensuring excellent adhesion between the zinc layer and the steel strip substrate is a core quality requirement. The basic principle is that after the steel strip enters the zinc bath, its surface reacts with the aluminum in the molten zinc, forming a thin and dense Fe-Al alloy layer (usually Fe2Al5). This alloy layer acts as an adhesion layer, effectively promoting a tight bond between the subsequent zinc layer and the steel substrate.

[0003] However, this reaction process is extremely sensitive to the cleanliness and chemical state of the strip surface. If oxides are present on the surface of the strip before it enters the zinc bath, these stable oxides will hinder the effective contact and reaction between aluminum and iron, resulting in the inability to form a uniform and continuous Fe-Al alloy adhesion layer, ultimately leading to defects in the adhesion of galvanized products.

[0004] To address the aforementioned problems, existing technologies generally employ the method of creating and maintaining a strong reducing atmosphere (typically a hydrogen-nitrogen mixture) within the annealing furnace. This approach aims to neutralize the oxidizing atmosphere by utilizing the reaction of reducing gases (such as hydrogen) with oxygen within the furnace, thereby preventing secondary oxidation of the strip steel during annealing. However, those skilled in the art have discovered inherent limitations in practice. Due to factors such as equipment sealing, the precision of the atmosphere control system, and production costs, the reducing atmosphere within the annealing furnace cannot completely and thoroughly eliminate all oxygen. Typically, a residual oxidizing atmosphere of 20 ppm to 50 ppm remains within the furnace.

[0005] The residual, low-concentration oxidizing atmosphere is particularly harmful to modern high-strength galvanized steel strip. To meet the strength requirements of industries such as automobiles and home appliances, steel strip typically contains various alloying elements such as silicon, manganese, and chromium. These reactive alloying elements readily react with residual oxygen to form corresponding oxides. Crucially, these alloy oxides formed at high temperatures in the annealing furnace possess extremely high stability and are difficult to reduce using conventional reducing atmospheres in subsequent processes. Once formed, these oxides firmly adhere to the steel strip surface, disrupting the formation of the Fe-Al alloy adhesion layer and becoming a persistent problem leading to poor adhesion of the galvanized layer, severely impacting product yield and performance.

[0006] Therefore, the existing technology that relies on neutralizing oxygen in a reducing atmosphere cannot fundamentally solve the problem of poor adhesion caused by the reaction of residual oxygen with alloying elements in the strip. A more effective and reliable technical means is urgently needed to overcome this technical bottleneck. Utility Model Content

[0007] This utility model provides a humidification device for galvanizing furnaces to solve the technical problems existing in the prior art. By setting up a humidification chamber in a certain temperature range in the furnace and introducing a certain proportion of wet nitrogen, the strip steel is effectively humidified and controlled, thereby realizing the controllable oxidation of the product and the effective control of surface adhesion.

[0008] This utility model includes the following technical solution: a humidification device for a galvanizing furnace, comprising a humidification chamber, wherein sealing rollers are provided at both the strip inlet and strip outlet on both sides of the humidification chamber; a temperature sensor for measuring the strip temperature is provided on the outer side of the sealing rollers; at least two sets of gas collecting pipes parallel to the strip are provided in the humidification chamber, and the gas collecting pipes are provided with gas outlet holes; the gas collecting pipes are respectively connected to a dry nitrogen pipe and a wet nitrogen pipe through an air inlet pipe, and both the dry nitrogen pipe and the wet nitrogen pipe are provided with control valves; a humidification water tank or a heating humidification device is provided on the wet nitrogen pipe; exhaust valves and exhaust pipes are provided on the upper and lower sides of the humidification chamber, and a pressure sensor is installed in the humidification chamber.

[0009] Furthermore, under normal production conditions, when producing ordinary galvanized steel strip, the temperature of the strip measured by the temperature sensor is 600℃-650℃.

[0010] Furthermore, both ends of each set of air collection pipes are connected outside the humidification chamber and connected to the air inlet pipe.

[0011] Furthermore, the gas inlet pipe enters the furnace from outside and connects to the gas collecting pipe. Both the dry nitrogen pipe and the wet nitrogen pipe are located outside the galvanizing furnace.

[0012] Furthermore, the gas collecting pipe has several air outlet holes evenly arranged on the side of the strip steel within the humidification chamber.

[0013] Furthermore, the diameter of the air outlet is 5mm, and the spacing between the outlets is 10mm.

[0014] Furthermore, the dry nitrogen pipe and the wet nitrogen pipe are respectively equipped with a first control valve and a second control valve, and the dry nitrogen pipe and the wet nitrogen pipe are connected to the air inlet pipe at the same point.

[0015] Furthermore, the second control valve is located at the air inlet of the humidifying water tank and connected to its bottom side, while the air outlet of the humidifying water tank is located at its top side.

[0016] Furthermore, the intake pipe is provided with a dew point detection device, a flow meter, and a heating device in sequence along the intake direction.

[0017] Furthermore, the second control valve is located at the air outlet of the heating and humidifying device, and the other end of the heating and humidifying device is the air inlet, with a water inlet pipe connected to its side; the water inlet pipe is equipped with a third control valve and a flow meter, through which demineralized water is added to the heating and humidifying device and vaporized into water vapor mixed with nitrogen.

[0018] Furthermore, the heating and humidifying device is equipped with a heating wire for heating nitrogen gas.

[0019] The advantages and positive effects of this utility model are as follows: This invention achieves effective humidification control of the strip steel by setting up a humidification chamber on the strip steel within a specified temperature range and introducing nitrogen gas with controllable humidity, thereby realizing controllable oxidation of the product. By controlling the oxide film, the uncontrollable oxidation of other elements is suppressed, thereby achieving effective control of surface adhesion.

[0020] The humidification device and the heating humidification device used in this utility model are both located outside the galvanizing furnace, which does not require high temperature resistance design and is convenient for daily maintenance. The humidification device uses a traditional water tank ventilation method to make the nitrogen gas contain a certain amount of moisture. The temperature of the humidified atmosphere is generally low, so a separate heating device is set up. The heating humidification device uses the method of directly introducing demineralized water into the nitrogen heating device to humidify the nitrogen gas. The structure is more streamlined and it is conducive to the precise control of moisture parameters.

[0021] This invention employs a dew point detection device installed on the air inlet pipe to monitor the ratio and flow rate of wet nitrogen and dry nitrogen, so as to adjust the opening of the control valve in a timely manner. Attached Figure Description

[0022] Figure 1 This is a schematic cross-sectional view of the main structure of this utility model; Figure 2 This is a left view of the main structure of this utility model; Figure 3 This is a schematic diagram of the gas source connection structure in Example 1; Figure 4 This is a schematic diagram of the gas source connection structure in Example 2; In the diagram, 1-humidification chamber; 2-sealing roller; 3-temperature sensor; 4-strip steel; 5-gas collecting pipe; 501-gas outlet; 6-gas inlet pipe; 7-dry nitrogen pipe; 8-wet nitrogen pipe; 9-humidification water tank; 10-heating and humidification device; 11-dew point detection device; 12-flow meter; 13-heating device; 14-first control valve; 15-second control valve; 16-third control valve; 17-exhaust valve; 18-exhaust pipe. Detailed Implementation

[0023] To further disclose the invention content, features, and effects of this utility model, the following examples are provided in conjunction with the accompanying drawings for detailed description. In the following description of the embodiments, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this patent and simplifying the description. They do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this patent.

[0024] In the following description of the embodiments, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0025] Example 1: See Appendix Figure 1-3 A humidification device for a galvanizing furnace includes a humidification chamber 1. Sealing rollers 2 are provided at both the inlet and outlet of the strip 4 on both sides of the humidification chamber 1. A set of sealing rollers 2 is provided inside the humidification chamber 1 at the inlet of the strip 4, and a set of sealing rollers 2 is provided both inside and outside the humidification chamber 1 at the outlet of the strip 4. A temperature sensor 3 for measuring the temperature of the strip 4 is provided on the outer side of the sealing rollers 2. Under normal production conditions, when producing ordinary galvanized steel strip, the temperature of the strip 4 measured by the temperature sensor 3 is 600℃-650℃. The humidification chamber 1 is equipped with at least two sets of gas collecting pipes 5 parallel to the strip steel 4, each with an outlet 501. The gas collecting pipes 5 are connected to a dry nitrogen pipe 7 and a wet nitrogen pipe 8 via an inlet pipe 6, both equipped with control valves. A humidification water tank 9 is mounted on the wet nitrogen pipe 8. Exhaust valves 17 and exhaust pipes 18 are located on the upper and lower sides of the humidification chamber 1. A pressure sensor is installed inside the humidification chamber 1, near the exhaust valves 17. The exhaust pipes 18 are connected to a waste gas recovery device or waste gas treatment device outside the galvanizing furnace, or directly discharged outside the factory building.

[0026] Both ends of each set of air collecting pipes 5 are connected outside the humidification chamber 1 and connected to the air inlet pipe 6. In this example, two sets of air collecting pipes 5 are connected to the air inlet pipe 6, but each set of air collecting pipes 5 can also be connected to the air inlet pipe 6 separately.

[0027] The inlet pipe 6 enters the furnace from outside and connects to the gas collecting pipe 5. Both the dry nitrogen pipe 7 and the wet nitrogen pipe 8 are located outside the galvanizing furnace. The gas collecting pipe 5 has several evenly spaced outlet holes 501 on the side facing the strip 4. The diameter of each outlet hole 501 is 5 mm, and the spacing between the holes is 10 mm.

[0028] like Figure 3 As shown, the dry nitrogen pipe 7 and the wet nitrogen pipe 8 are respectively equipped with a first control valve 14 and a second control valve 15, and the dry nitrogen pipe 7 and the wet nitrogen pipe 8 are connected to the inlet pipe 6 at the same location. The second control valve 15 is located at the air inlet end of the humidifying water tank 9 and connected to its bottom side, while the air outlet end of the humidifying water tank 9 is located at its top side. Along the air inlet direction, the inlet pipe 6 is sequentially equipped with a dew point detection device 11, a flow meter 12, and a heating device 13. The flow meter 12, the dew point detection device 11, and the heating device 13 are all located outside the galvanizing furnace.

[0029] Operating Procedure: Before starting the machine, a measured amount of demineralized water is injected into the humidifying water tank 9 to enable its humidification function. After the temperature sensor 3 checks that the temperature has reached the target temperature, the second control valve 15 is opened to start the humidification system. The ratio of dry nitrogen to wet nitrogen is adjusted by adjusting the opening of the first control valve 14 and the second control valve 15 to control the dew point. The dew point is adjusted according to the degree of oxidation on the surface of the strip steel 4. During the ventilation process, the exhaust valve 17 is intermittently opened according to the data from the pressure sensor to maintain the air pressure. After continuous ventilation for a certain period of time, an oxide film forms on the surface of the strip steel 4. The second control valve 15 is then closed to stop the flow of wet nitrogen, and dry nitrogen is introduced instead. After continuing to introduce dry nitrogen for a certain period of time, the atmosphere in the humidifying chamber 1 is replaced. Then, the sealing roller 2 is opened to send the next section of strip steel 4 into the humidifying chamber 1.

[0030] Example 2: See Appendix Figure 1 , 2 4. A humidification device for a galvanizing furnace, wherein a heating and humidification device 10 is provided on the wet nitrogen pipe 8; a second control valve 15 is provided at the outlet end of the heating and humidification device 10, and the other end of the heating and humidification device 10 is the inlet end, with a water inlet pipe connected to its side; a third control valve 16 and a flow meter 11 are provided on the water inlet pipe, through which demineralized water is added to the heating and humidification device 10 and vaporized into water vapor to mix with nitrogen. The heating and humidification device 10 is provided with a heating wire for heating nitrogen. A dew point detection device 11 can be provided on the inlet pipe 6 to monitor the ratio of dry to wet nitrogen, and the ratio of dry to wet nitrogen can also be calculated based on the flow rate of the demineralized water. Other structures are basically the same as in Embodiment 1.

[0031] Working Principle: Before starting the machine, ensure the inlet pipe is filled with demineralized water and has humidification function. After temperature sensor 3 checks that the temperature has reached the target temperature, open the second control valve 15 and the third control valve 16 to start the humidification system. Adjust the opening of the first control valve 14 and the second control valve 15 to regulate the ratio of dry nitrogen to wet nitrogen and control the dew point; or directly adjust the opening of the third control valve 16 to control the dew point. Adjust the dew point according to the degree of oxidation on the surface of the strip steel 4. During the ventilation process, intermittently open the exhaust valve 17 to maintain the air pressure based on the data from the air pressure sensor. After continuous ventilation for a certain period of time, an oxide film forms on the surface of the strip steel 4. Close the second control valve 15 and the third control valve 16 to stop the flow of wet nitrogen and switch to only dry nitrogen. Continue ventilation for a certain period of time to replace the atmosphere in the humidification chamber 1. Then open the sealing roller 2 to send the next section of strip steel 4 into the humidification chamber 1.

[0032] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications under the guidance of the present invention without departing from the spirit and scope of the claims. These modifications all fall within the protection scope of the present invention.

Claims

1. A humidification device for a galvanizing furnace, characterized in that: The device includes a humidification chamber, with sealing rollers installed at both the strip inlet and outlet on both sides. A temperature sensor for measuring the strip temperature is installed on the outer side of each sealing roller. The humidification chamber contains at least two sets of gas collecting pipes parallel to the strip, each with an outlet. These pipes are connected to a dry nitrogen pipe and a wet nitrogen pipe via inlet pipes, both equipped with control valves. A humidification water tank or a heating and humidification device is installed on the wet nitrogen pipe. Exhaust valves and exhaust pipes are located on the upper and lower sides of the humidification chamber, and a pressure sensor is installed within the chamber.

2. The humidification device for a galvanizing furnace according to claim 1, characterized in that: Both ends of each set of air collection pipes are connected outside the humidification chamber and connected to the air inlet pipe.

3. The humidification device for a galvanizing furnace according to claim 2, characterized in that: The air inlet pipe enters the furnace from outside and connects to the gas collecting pipe.

4. The humidification device for a galvanizing furnace according to claim 1, characterized in that: The gas collecting pipe has several air outlets evenly arranged on the side of the strip steel in the humidification chamber.

5. A humidification device for a galvanizing furnace according to claim 4, characterized in that: The diameter of the air outlet is 5mm, and the spacing between the outlets is 10mm.

6. A humidification device for a galvanizing furnace according to any one of claims 1-5, characterized in that: The dry nitrogen pipe and the wet nitrogen pipe are respectively equipped with a first control valve and a second control valve, and the dry nitrogen pipe and the wet nitrogen pipe are connected to the air inlet pipe at the same point.

7. A humidification device for a galvanizing furnace according to claim 6, characterized in that: The second control valve is located at the air inlet of the humidifying water tank and connected to its bottom side, while the air outlet of the humidifying water tank is located at its top side.

8. A humidification device for a galvanizing furnace according to claim 7, characterized in that: The air intake pipe is equipped with a dew point detection device, a flow meter, and a heating device in sequence along the air intake direction.

9. A humidification device for a galvanizing furnace according to claim 6, characterized in that: The second control valve is located at the air outlet of the heating and humidifying device, and the other end of the heating and humidifying device is the air inlet, with a water inlet pipe connected to its side; a third control valve and a flow meter are provided on the water inlet pipe.

10. A humidification device for a galvanizing furnace according to claim 9, characterized in that: The heating and humidifying device is equipped with a heating wire for heating nitrogen gas.

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