A hot galvanizing device and method with uniform plating

Abstract

The application belongs to the technical field of galvanization, and discloses a hot galvanizing device with uniform coating, which comprises a galvanizing pool and a supporting plate symmetrically arranged on the top of the galvanizing pool, and further comprises a scraper mechanism fixedly arranged on the top of the supporting plate, wherein the scraper mechanism comprises a lead screw motor and a supporting sliding block arranged at two ends of the top of the supporting plate respectively, and the supporting sliding block is threadedly sleeved on the lead screw part of the lead screw motor. According to the above scheme, when the metal part is subjected to the galvanizing operation, the nitrogen gas is filled in the galvanizing pool and covers the upper layer of the molten zinc liquid, the lead screw motor is operated to drive the supporting sliding block to move and drive the scraper to move to the edge of the galvanizing pool, the side surface of the scraper pushes the oxidized part of the upper layer of the molten zinc liquid to move to the edge of the galvanizing pool in the moving process of the scraper, meanwhile, the surface layer of the molten zinc liquid is isolated from the external gas by the assistance of the nitrogen gas, and at this time, the operator can put the metal part into the galvanizing pool by the hoisting equipment to perform the galvanizing operation.

Description

Technical Field

[0001] This invention belongs to the field of galvanizing technology, specifically a hot-dip galvanizing apparatus and method for achieving uniform coating. Background Technology

[0002] Hot-dip galvanizing is a corrosion-resistant process that involves immersing steel products in molten zinc to form a dense zinc-iron alloy protective layer on their surface.

[0003] In the hot-dip galvanizing process, the parts first need to be degreased to remove surface oil, pickled to remove iron oxide and rust layers, and coated with flux to prevent oxidation. Then, the workpiece is immersed in molten zinc at approximately 450°C, where a metallurgical reaction occurs to form a zinc-iron alloy layer and a pure zinc coating. Finally, the workpiece is removed and cooled to solidify, achieving the galvanizing process. However, in actual operation, the surface of the molten zinc is easily exposed to external gases and oxidized. If the resulting zinc ash and dross are not removed promptly, they will adhere to the workpiece surface or the molten zinc, causing localized roughness and uneven thickness of the coating. Furthermore, removing oxide impurities from the molten zinc surface can easily cause excessive fluctuations in the zinc solution, leading to safety hazards. Therefore, to solve these problems, a hot-dip galvanizing device and method for achieving uniform coating is proposed. Summary of the Invention

[0004] To address the problems mentioned in the background art, the present invention provides a hot-dip galvanizing apparatus and method for achieving uniform coating, which solves the problem that the molten zinc in the surface layer of the galvanizing bath oxidizes and affects the uniformity of the coating on subsequent metal parts.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a hot-dip galvanizing apparatus with uniform coating, comprising a galvanizing tank and a support plate symmetrically installed on the top of the galvanizing tank, further comprising: a scraper mechanism fixedly installed on the top of the support plate, the scraper mechanism comprising a lead screw motor and a support slider respectively installed at both ends of the top of the support plate, the support slider being threaded onto the lead screw portion of the lead screw motor, and the support slider sliding on the top of the support plate, a scraper component for scraping off the molten zinc oxide layer on the surface of the galvanizing tank is provided between the two support sliders; the galvanizing tank is filled with nitrogen gas located above the molten zinc layer.

[0006] Preferably, the top of the support plate is provided with a guide rib, which can contact the bottom of the support slider on the outward side.

[0007] Preferably, the two ends of the scraper are rotatably mounted on two support sliders; Both of the support sliders are fixedly mounted with support top frames. The support top frames overlap with the shaft of the scraper in the vertical direction. One end of the support top frame extends above the end of the scraper and is hinged with a spring telescopic rod. The other end of the spring telescopic rod is hinged to the top of the scraper. In the initial state, the top of the scraper will remain tilted due to the elastic force of the spring telescopic rod; The top of the galvanizing tank is also equipped with two sets of pins for changing the tilt direction of the scraper components.

[0008] Preferably, the ejector pin includes a top column installed symmetrically at the top edge of the galvanizing tank, and the top of the scraper can be kept stationary by the end limit when the scraper moves, so that the part located below the scraper shaft can continue to move and deflect.

[0009] Preferably, a set of limiting rods is fixedly connected to each of the two supporting sliders on opposite sides, and the limiting rods are located on both sides of the scraper component; In the initial state, the scraper is located on one side of the shaft body and abuts against the limiting stop.

[0010] Preferably, the spring telescopic rod includes a sleeve rod and a spring piston rod; wherein the top end of the spring piston rod is hinged to the support top frame, the bottom end of the sleeve rod is hinged to the top of the scraper, the bottom end of the spring piston rod is movably sleeved in the sleeve rod cavity, and in the initial state, the spring piston rod has an upward tendency due to its own elastic force.

[0011] Preferably, the upper part of the spring piston rod is provided with an exhaust port that can communicate with the spring piston rod and the sleeve rod cavity, and a one-way valve plate that can conduct upward unidirectionally is installed in the spring piston rod cavity, and a valve disc hole is provided in the middle of the one-way valve plate.

[0012] Preferably, the bottom of the scraper is fitted with an auxiliary scraper made of aluminum material, and a set of protective arc plates are installed symmetrically on the top of the auxiliary scraper.

[0013] Preferably, the scraper component has a guide hole located above the auxiliary scraper.

[0014] A method for using a hot-dip galvanizing apparatus for achieving uniform coating, wherein the method of using such an apparatus is as follows: In use, nitrogen is first filled into the galvanizing tank and used to cover the upper layer of molten zinc. When the operator needs to galvanize the metal parts, the support slider is moved by the screw motor and the scraper is moved to the edge of the galvanizing tank. During the movement of the scraper, its side will push the oxidized part on the upper layer of molten zinc to the edge of the galvanizing tank. At the same time, the nitrogen helps to isolate the surface of the molten zinc from the outside gas. At this time, the operator can put the metal parts into the galvanizing tank for galvanizing using the hoisting equipment. Secondly, the scraper is initially tilted due to the support of the spring telescopic rod. As the scraper moves toward the edge of the galvanizing tank, the top of the scraper comes into contact with the end of the top column, forcing the scraper to deflect around the axis. During the deflection of the scraper, the spring telescopic rod retracts first. After the scraper passes the vertical state and changes direction, the spring telescopic rod extends and resets, providing support for the scraper after it changes its tilt direction. By changing the tilt direction of the reciprocating scraper mechanism, it can move in the direction of flow and reduce resistance, making it easier for zinc oxide to be pushed toward the edge of the tank to avoid accumulation or backflow. When the spring telescopic rod is in the compressed or rebound state, the bottom end of the spring piston rod will move downward inside the sleeve rod and discharge the gas inside the sleeve rod to the outside. When the scraper piece crosses the vertical state and changes its deflection direction, the piston end at the bottom of the spring piston rod will move upward inside the sleeve rod. The opening of the valve orifice will restrict the outside gas from entering the sleeve rod through the valve orifice. At this time, the spring telescopic rod will slowly extend. At the same time, when the scraper piece changes its deflection direction from the vertical state, it will also be affected by the spring telescopic rod and deflect slowly, avoiding the situation where the molten zinc liquid is splashed up due to the excessive amplitude when the scraper piece deflects rapidly.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The above scheme fills the galvanizing tank with nitrogen and covers the upper layer of molten zinc. When the operator needs to galvanize the metal parts, the support slider is moved by running the screw motor and the scraper is moved to the edge of the galvanizing tank. During the movement of the scraper, its side will push the oxidized part of the upper layer of molten zinc to the edge of the galvanizing tank. At the same time, the surface of the molten zinc is isolated from the outside gas by the assistance of nitrogen. At this time, the operator can put the metal parts into the galvanizing tank for galvanizing by hoisting equipment. (2) The above scheme uses the support of the spring telescopic rod to make the scraper piece in an inclined state at the beginning. When the scraper piece moves toward the edge of the galvanizing pool, the top of the scraper piece will abut against the end of the top column piece, thereby forcing the scraper piece to deflect around the axis. During the deflection of the scraper piece, the spring telescopic rod will retract first. After the scraper piece passes the vertical state and changes direction, the spring telescopic rod will extend and reset, and provide support for the scraper piece after changing its tilt direction. By changing the tilt direction of the reciprocating scraper mechanism, it can move in the direction of flow and reduce resistance, making it easier for zinc oxide to be pushed to the edge of the pool to avoid accumulation or backflow. (3) In the above scheme, when the spring telescopic rod is in the compression or rebound state, the bottom end of the spring piston rod will move downward in the sleeve rod and discharge the gas in the sleeve rod to the outside. When the scraper passes the vertical state and changes the deflection direction, the piston end at the bottom of the spring piston rod will move upward in the sleeve rod. The opening of the valve hole will restrict the external gas from entering the sleeve rod through the valve hole. At this time, the spring telescopic rod will slowly extend. At the same time, when the scraper changes from the vertical state and changes the deflection direction, it will also be affected by the spring telescopic rod and deflect slowly, avoiding the situation where the molten zinc liquid is splashed up when the scraper deflects too quickly. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the scraper mechanism of the present invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the structure of the supporting slider of the present invention; Figure 5 This is a schematic side cross-sectional view of the galvanizing tank of the present invention; Figure 6 This is a side sectional view of the spring telescopic rod of the present invention; Figure 7 for Figure 6 Enlarged view of point B in the middle; Figure 8 for Figure 6 A magnified view of point C in the middle.

[0017] In the diagram: 1. Galvanizing tank; 11. Support plate; 12. Guide rib; 2. Top column; 3. Scraper mechanism; 31. Lead screw motor; 32. Support slider; 321. Support top frame; 322. Limiting stop bar; 33. Scraper component; 331. Auxiliary scraper; 332. Protective arc plate; 333. Guide hole; 4. Spring telescopic rod; 41. Sleeve rod; 42. Spring piston rod; 421. Exhaust port; 422. One-way valve plate; 423. Valve disc hole. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figures 1 to 8 As shown, the present invention provides a hot-dip galvanizing apparatus and method with uniform coating, including a galvanizing tank 1 and a support plate 11 symmetrically installed on the top of the galvanizing tank 1, and further including: a scraper mechanism 3 fixedly installed on the top of the support plate 11. The scraper mechanism 3 includes a lead screw motor 31 and a support slider 32 respectively installed on both ends of the top of the support plate 11. The support slider 32 is threaded onto the lead screw part of the lead screw motor 31 and slides on the top of the support plate 11. A scraper component 33 for scraping off the molten zinc oxide liquid on the inner surface of the galvanizing tank 1 is provided between the two support sliders 32. The galvanizing bath 1 is filled with nitrogen gas located above the molten zinc layer; The top of the support plate 11 is provided with a guide rib 12, which can contact the bottom of the support slider 32 on the outward side and limit the movement of the support slider 32. By using the above solution, nitrogen is filled into the galvanizing bath 1 and covers the upper layer of molten zinc. When the operator needs to galvanize the metal parts, the screw motor 31 drives the support slider 32 to move and moves the scraper 33 towards the edge of the galvanizing bath 1. During the movement of the scraper 33, its side will push the oxidized part of the upper layer of molten zinc towards the edge of the galvanizing bath 1. At the same time, with the help of nitrogen, the surface of the molten zinc is isolated from the outside gas. At this time, the operator can put the metal parts into the galvanizing bath 1 for galvanizing using the hoisting equipment, thus solving the problem that the molten zinc on the surface of the galvanizing bath will oxidize and affect the uniformity of the coating of the subsequent metal parts.

[0020] like Figures 1-5 As shown, the two ends of the scraper 33 are rotatably mounted on two support sliders 32 respectively; a support top frame 321 is fixedly mounted on the top of each of the two support sliders 32. The support top frame 321 has a portion that overlaps with the shaft of the scraper 33 in the vertical direction. One end of the support top frame 321 extends to the top of the end of the scraper 33 and is hinged to a spring telescopic rod 4. The other end of the spring telescopic rod 4 is hinged to the top of the scraper 33. In the initial state, the top of the scraper 33 will remain tilted due to the elastic force of the spring telescopic rod 4; The top of the galvanizing tank 1 is also equipped with two sets of ejector pins for changing the tilt direction of the scraper component 33; the ejector pins include ejector pins 2 installed symmetrically on the top edge of the galvanizing tank 1. When the top of the scraper component 33 moves, it can be kept stationary by the limit stop bar 322, so that the part located below the shaft of the scraper component 33 continues to move and deflect. By adopting the above scheme, the scraper 33 is initially tilted by the spring telescopic rod 4. When the scraper 33 moves toward the edge of the galvanizing tank 1, the top of the scraper 33 will abut against the end of the top column 2, thereby forcing the scraper 33 to deflect around the axis. During the deflection of the scraper 33, the spring telescopic rod 4 will retract first. After the scraper 33 passes the vertical state and changes direction, the spring telescopic rod 4 will extend and reset, and provide support for the scraper 33 after changing its tilt direction. By changing the tilt direction of the reciprocating scraper mechanism 3, it can move in the direction of flow and reduce resistance, making it easier for zinc oxide to be pushed to the edge of the tank to avoid accumulation or backflow.

[0021] like Figure 3 , Figure 4 and Figure 6 As shown, a set of limiting rods 322 are fixedly connected to the opposite side of the two supporting sliders 32. The limiting rods 322 are located on both sides of the scraper 33. In the initial state, the scraper 33 is located on the side of the shaft part and abuts against the limiting rods 322. By adopting the above solution, the limit stop bar 322 can support the scraper 33 in the deflection state, thus preventing accidental displacement caused by vibration or load changes.

[0022] like Figure 1 and Figures 3-7 As shown, the spring telescopic rod 4 includes a sleeve rod 41 and a spring piston rod 42; wherein the top end of the spring piston rod 42 is hinged to the support top frame 321, the bottom end of the sleeve rod 41 is hinged to the top of the scraper 33, the bottom end of the spring piston rod 42 is movably sleeved in the cavity of the sleeve rod 41, and in the initial state, the spring piston rod 42 has an upward tendency due to its own elastic force. The upper part of the spring piston rod 42 is provided with an exhaust port 421 that can communicate with the cavity of the spring piston rod 42 and the sleeve rod 41. A one-way valve plate 422 that can conduct upward unidirectionally is installed in the cavity of the spring piston rod 42, and a valve disc hole 423 is provided in the middle of the one-way valve plate 422. Using the above scheme, during the compression or rebound state of the spring telescopic rod 4, the bottom end of the spring piston rod 42 will move downward inside the sleeve rod 41 and discharge the gas inside the sleeve rod 41. When the scraper 33 crosses the vertical state and changes its deflection direction, the piston end at the bottom of the spring piston rod 42 will move upward inside the sleeve rod 41. The opening of the valve hole 423 will restrict the external gas from entering the sleeve rod 41 through the valve hole 423. At this time, the spring telescopic rod 4 will slowly extend. At the same time, when the scraper 33 changes its deflection direction from the vertical state, it will also be affected by the spring telescopic rod 4 and deflect slowly, avoiding the situation where the scraper 33 deflects too much and splashes up the molten zinc when it deflects quickly.

[0023] like Figures 4-8 As shown, the bottom of the scraper component 33 is fitted with an auxiliary scraper 331 made of aluminum material, and a set of protective arc plates 332 are installed symmetrically on the top of the auxiliary scraper 331. The scraper component 33 has a guide hole 333 located above the auxiliary scraper 331; By adopting the above scheme, by using an aluminum auxiliary scraper 331, which has a significantly higher melting point than zinc, it can float stably in the molten zinc liquid, thereby automatically adapting to the dynamic changes in the surface of the molten zinc liquid. The setting of the protective arc plate 332 will prevent the molten zinc liquid from passing over the top of the scraper 33 when the scraper 33 moves. When the scraper 33 moves, the nitrogen gas in the galvanizing bath 1 will flow through the guide hole 333, which can prevent some nitrogen gas from overflowing through the edge of the galvanizing bath 1 when the scraper 33 scrapes off the oxidized molten zinc layer.

[0024] Working principle and usage process of this invention: Nitrogen gas is filled into the galvanizing tank 1 and covers the upper layer of molten zinc. When the operator needs to galvanize the metal parts, the support slider 32 is moved by the screw motor 31 and the scraper 33 is moved towards the edge of the galvanizing tank 1. During the movement of the scraper 33, its side will push the oxidized part of the upper layer of molten zinc towards the edge of the galvanizing tank 1. At the same time, the surface of the molten zinc is isolated from the outside gas by the assistance of nitrogen gas. At this time, the operator can put the metal parts into the galvanizing tank 1 for galvanizing by the hoisting equipment. By setting the spring telescopic rod 4, the scraper 33 is initially in an inclined state. When the scraper 33 moves toward the edge of the galvanizing pool 1, the top of the scraper 33 will abut against the end of the top column 2, thereby forcing the scraper 33 to deflect around the axis. During the deflection of the scraper 33, the spring telescopic rod 4 will retract first. After the scraper 33 passes the vertical state and changes direction, the spring telescopic rod 4 will extend and reset, and provide support for the scraper 33 after changing its tilt direction. By changing the tilt direction of the reciprocating scraper mechanism 3, it can move in accordance with the flow direction and reduce resistance. Thus, it can move forward automatically in a paddle manner when moving in both directions, making it easier to push zinc oxide to the edge of the pool to avoid accumulation or backflow. Meanwhile, during the compression or rebound of the spring telescopic rod 4, the bottom end of the spring piston rod 42 will descend within the sleeve rod 41 and expel the gas inside the sleeve rod 41. When the scraper 33 crosses the vertical position and changes its deflection direction, the piston end at the bottom of the spring piston rod 42 will rise within the sleeve rod 41. The opening of the valve hole 423 will limit the speed at which external gas enters the sleeve rod 41 through the valve hole 423. At this time, the spring telescopic rod 4 will slowly extend. At the same time, when the scraper 33 changes its deflection direction from the vertical position, it will also be affected by the spring telescopic rod 4 and deflect slowly. This avoids the situation where the scraper 33 deflects too quickly and causes the molten zinc to be splashed up. This achieves automatic forward movement in a paddle manner during bidirectional movement without causing large fluctuations in the molten zinc, thus avoiding safety hazards.

[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hot-dip galvanizing apparatus for uniform coating, comprising a galvanizing tank (1) and support plates (11) symmetrically installed on top of the galvanizing tank (1), characterized in that, Also includes: A scraper mechanism (3) is fixedly installed on the top of the support plate (11). The scraper mechanism (3) includes a lead screw motor (31) and a support slider (32) respectively installed at both ends of the top of the support plate (11). The support slider (32) is threaded onto the lead screw part of the lead screw motor (31), and the support slider (32) slides on the top of the support plate (11). A scraper component (33) for scraping off the molten zinc liquid oxidized on the inner surface of the galvanizing pool (1) is provided between the two support sliders (32). The galvanizing bath (1) is filled with nitrogen gas located above the molten zinc layer.

2. The hot-dip galvanizing apparatus for uniform coating according to claim 1, characterized in that: The top of the support plate (11) is provided with a guide rib (12), which can contact the bottom of the support slider (32) on the outward side.

3. The hot-dip galvanizing apparatus for uniform coating according to claim 1, characterized in that: The scraper (33) is rotatably mounted on two support sliders (32) at both ends; The top of each of the two support sliders (32) is fixedly mounted with a support top frame (321). The support top frame (321) has a portion that overlaps with the shaft of the scraper (33) in the vertical direction. One end of the support top frame (321) extends above the end of the scraper (33) and is hinged with a spring telescopic rod (4). The other end of the spring telescopic rod (4) is hinged to the top of the scraper (33). In the initial state, the top of the scraper (33) will remain tilted due to the elastic force of the spring telescopic rod (4); The top of the galvanizing tank (1) is also equipped with two sets of pins for changing the tilt direction of the scraper (33).

4. The hot-dip galvanizing apparatus for uniform coating according to claim 3, characterized in that: The ejector pin includes a top post (2) installed symmetrically on the top edge of the galvanizing pool (1). When the top of the scraper (33) moves, it can be stopped by the end of the limiting stop (322) and remain stationary, so that the part located below the shaft of the scraper (33) continues to move and deflect.

5. The hot-dip galvanizing apparatus for uniform coating according to claim 3, characterized in that: A set of limiting rods (322) are fixed to one side of each of the two supporting sliders (32), and the limiting rods (322) are located on both sides of the scraper (33); In the initial state, the scraper (33) is located on one side of the shaft part and abuts against the limiting stop (322).

6. The hot-dip galvanizing apparatus for uniform coating according to claim 3, characterized in that: The spring telescopic rod (4) includes a sleeve rod (41) and a spring piston rod (42). The top end of the spring piston rod (42) is hinged to the support top frame (321), the bottom end of the sleeve rod (41) is hinged to the top of the scraper (33), the bottom end of the spring piston rod (42) is movably sleeved in the cavity of the sleeve rod (41), and in the initial state, the spring piston rod (42) has an upward tendency due to its own elastic force.

7. The hot-dip galvanizing apparatus for uniform coating according to claim 6, characterized in that: The upper part of the spring piston rod (42) is provided with an exhaust port (421) that can communicate with the cavity of the spring piston rod (42) and the sleeve rod (41). The cavity of the spring piston rod (42) is equipped with a one-way valve plate (422) that can conduct upward unidirectionally, and a valve disc hole (423) is provided in the middle of the one-way valve plate (422).

8. The hot-dip galvanizing apparatus for uniform coating according to claim 1, characterized in that: The bottom of the scraper component (33) is fitted with an auxiliary scraper (331) made of aluminum material, and a set of protective arc plates (332) are installed symmetrically on the top of the auxiliary scraper (331).

9. The hot-dip galvanizing apparatus for uniform coating according to claim 8, characterized in that: The scraper component (33) has a guide hole (333) located above the auxiliary scraper (331).

10. A method of using a hot-dip galvanizing apparatus for uniform coating, comprising using a hot-dip galvanizing apparatus for uniform coating as described in any one of claims 1-9, characterized in that, The usage method is as follows: When in use, nitrogen is first filled into the galvanizing tank (1) and covered on the upper layer of molten zinc. When the operator needs to galvanize the metal parts, the support slider (32) is moved by running the screw motor (31) and the scraper (33) is moved towards the edge of the galvanizing tank (1). During the movement of the scraper (33), its side will push the oxidized part on the upper layer of molten zinc towards the edge of the galvanizing tank (1). At the same time, the surface of the molten zinc is isolated from the outside gas by the assistance of nitrogen. At this time, the operator can put the metal parts into the galvanizing tank (1) for galvanizing by hoisting equipment. Secondly, the scraper (33) is initially tilted by the support of the spring telescopic rod (4). When the scraper (33) moves toward the edge of the galvanizing pool (1), the top of the scraper (33) will abut against the end of the top column (2), thereby forcing the scraper (33) to deflect around the axis. During the deflection of the scraper (33), the spring telescopic rod (4) will retract first. After the scraper (33) passes the vertical state and changes direction, the spring telescopic rod (4) will extend and reset and provide support for the scraper (33) after changing its tilt direction. By changing the tilt direction of the reciprocating scraper mechanism (3), it can move in the direction of flow and reduce resistance, making it easier for zinc oxide to be pushed to the edge of the pool to avoid accumulation or backflow. When the spring telescopic rod (4) is in the compression or rebound state, the bottom end of the spring piston rod (42) will move downward in the sleeve rod (41) and discharge the gas in the sleeve rod (41) outward. When the scraper (33) crosses the vertical state and changes the deflection direction, the piston end at the bottom of the spring piston rod (42) will move upward in the sleeve rod (41). The opening of the valve hole (423) will restrict the external gas from entering the sleeve rod (41) through the valve hole (423). At this time, the spring telescopic rod (4) will slowly extend. At the same time, when the scraper (33) changes from the vertical state and changes the deflection direction, it will also be affected by the spring telescopic rod (4) and deflect slowly, avoiding the situation where the molten zinc liquid is splashed up when the scraper (33) deflects too quickly.

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