Hot-rolled ribbed steel bar oxygen-free on-line galvanizing device

Abstract

The application provides a hot-rolled ribbed steel bar oxygen-free on-line galvanizing device, which comprises a reduction sealing cover and a galvanizing sealing cover in communication, and a reduction mechanism in the reduction sealing cover, a galvanizing mechanism in the galvanizing sealing cover and an air knife mechanism; the reduction mechanism comprises a reduction cylinder horizontally arranged and internally traversed by a rectangular channel, and the two ends of the reduction cylinder are respectively connected with a head nitrogen pipe and a tail nitrogen pipe; a plurality of mixed reduction gas inlets are arranged in parallel along the length direction of the middle part of the reduction cylinder; the galvanizing mechanism comprises a zinc pot, a galvanizing tank arranged above the zinc pot and a zinc liquid lifting assembly for transferring the zinc liquid from the zinc pot to the galvanizing tank. The surface treatment, galvanizing and coating thickness control are all carried out in a nitrogen atmosphere environment, so that the oxygen harm is avoided, and meanwhile, the on-line galvanizing is used to replace the original immersion galvanizing, so that the galvanizing requirements of ribbed steel bars with any length can be met, and a plurality of ribbed steel bars can be simultaneously galvanized, so that the galvanizing efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of ribbed steel bar technology, and more specifically to an oxygen-free online galvanizing device for hot-rolled ribbed steel bars. Background Technology

[0002] Hot-rolled ribbed steel bars, commonly known as threaded steel, possess high strength, high toughness, and good seismic performance, making them an ideal steel product for high-rise buildings and widely used in the field of concrete construction. To increase the corrosion resistance of the steel bars and improve the strength and lifespan of reinforced concrete, hot-rolled ribbed steel bars are typically hot-dip galvanized. After hot-dip galvanizing, the surface of the steel bar is completely covered by a pure zinc layer for physical protection. A Zn-Fe alloy layer is also formed between the pure zinc layer and the steel bar matrix, isolating the steel bar matrix from the atmosphere and thus protecting it from corrosion.

[0003] The existing technology involves downstream galvanizing plants using ribbed steel bars of a certain length (a few meters) produced by upstream hot rolling plants as raw materials. The ribbed steel bars at room temperature are ground to remove iron oxide scale, degreased, heated, and then bundled and hoisted into a zinc pot for hot-dip galvanizing and post-galvanizing treatment. This is a discontinuous, small-batch, short-size production process, which is not suitable for galvanizing steel bars longer than ten meters. At the same time, it results in high labor intensity for workers, poor working environment, low production efficiency, low output, and high energy consumption per unit.

[0004] Since ribbed steel bars are in a high-temperature state during galvanizing, once the iron oxide scale is removed and the steel substrate is exposed, the steel substrate is easily oxidized by the air during transportation, which will affect the subsequent galvanizing effect. Moreover, during the galvanizing process, the high-temperature steel bars will inevitably undergo an oxidation reaction to generate iron oxide scale, which will affect the bonding strength between the coating and the substrate.

[0005] Therefore, how to avoid the influence of oxygen on the galvanization of ribbed steel bars, improve the bonding strength between the coating and the substrate, and solve the problem that existing galvanizing technology cannot meet the requirements for galvanizing steel bars longer than ten meters has become a key factor restricting the mass production of galvanized ribbed steel bars. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides an oxygen-free online galvanizing device for hot-rolled ribbed steel bars, which solves the problem of oxygen affecting the steel bar matrix and achieves online galvanizing, meeting the galvanizing requirements of ribbed steel bars of any length.

[0007] The technical solution adopted by this invention to solve its technical problem is: A hot-rolled ribbed steel bar oxygen-free online galvanizing device includes a reduction sealing cover and a galvanizing sealing cover connected by a transfer channel, as well as a reduction mechanism and a galvanizing mechanism disposed within the reduction sealing cover; the front end of the reduction sealing cover is provided with an inlet for the ribbed steel bar to pass through, and the rear end of the galvanizing sealing cover is provided with an outlet for the ribbed steel bar to exit. The reduction mechanism includes a horizontally arranged reduction cylinder with a rectangular channel running through its interior. The two ends of the reduction cylinder are connected to a head nitrogen pipe and a tail nitrogen pipe, respectively. The head nitrogen pipe and tail nitrogen pipe pass through a reduction sealing cover and are connected to a compressed nitrogen pipeline. Multiple mixed reducing gas inlets are arranged in parallel along the length of the reduction cylinder, and these inlets are connected to a mixed reducing gas source outside the reduction cylinder. The nitrogen pressure introduced into the head nitrogen pipe and tail nitrogen pipe is greater than the mixed reducing gas pressure introduced into the mixed reducing gas inlets. The galvanizing mechanism includes a galvanizing tank, a zinc pot, and a zinc liquid lifting assembly. The zinc pot contains molten zinc, and the galvanizing tank is horizontally positioned above the zinc pot along its length. A zinc liquid lifting assembly is provided on one side of the galvanizing tank to lift the molten zinc in the zinc pot to a higher position and pour it into the galvanizing tank.

[0008] A further improvement of the present invention is that the mixed reducing gas is a nitrogen mixture, wherein the hydrogen content is 5% to 8%.

[0009] A further improvement of the present invention is that: a water removal and descaling device is also provided inside the reduction sealing cover; the water removal and descaling device is located upstream of the reduction mechanism.

[0010] A further improvement of the present invention is that: the interior of the descaling device has a transverse channel that can accommodate multiple parallel ribbed steel bars, the front end of the channel corresponds to the inlet of the reduction sealing cover, and the rear end of the channel corresponds to the rectangular channel of the reduction cylinder; a purge air knife is provided at the top and bottom of the descaling device, and the purge air knife is connected to a high-pressure nitrogen pipe.

[0011] A further improvement of the present invention is that the blowing direction of the blowing air knife makes an angle of 45° with the horizontal direction.

[0012] A further improvement of the present invention is that the top of the reduction sealing cover and the top of the galvanized sealing cover are connected by an escape pipe, and an exhaust tower for high-altitude nitrogen emission is provided at the tail end of the galvanized sealing cover.

[0013] A further improvement of the present invention is that: the zinc liquid lifting assembly includes a lifting wheel, zinc buckets, a tilting support block, and a lifting motor for driving the lifting wheel to rotate; the lifting wheel is a rotary supported circular wheel, and several zinc buckets are connected circumferentially along the axis of the lifting wheel. The zinc buckets can be immersed in the zinc pot as the lifting wheel rotates and lift the zinc liquid to a high place for transfer; the lifting wheel is also provided with a tilting support block for gradually tilting the zinc buckets lifted out of the zinc pot toward the galvanizing tank side.

[0014] A further improvement of the present invention is that the tilting support block is fixedly mounted on the hoist wheel and does not rotate with the rotation of the hoist wheel, and the tilting support block is a wedge-shaped block with a gradually increasing inclination angle.

[0015] A further improvement of the present invention is that a slag discharge component for removing zinc dross from the zinc liquid is also provided on the opposite side of the zinc liquid lifting component.

[0016] A further improvement of the present invention is that: the air knife mechanism includes a first air knife, a second air knife, and a third air knife arranged sequentially downstream of the galvanizing tank; the first air knife, the second air knife, and the third air knife are all hollow "U"-shaped structures, and the first air knife, the second air knife, and the third air knife are also provided with nozzles that communicate with their internal air chambers; the blowing direction of the first air knife is inclined toward the running direction of the ribbed steel bar, the blowing direction of the second air knife is perpendicular to the running direction of the ribbed steel bar, and the blowing direction of the third air knife is inclined in the opposite direction to the running direction of the ribbed steel bar.

[0017] A further improvement of the present invention is that the angle α between the blowing direction of the first air knife and the running direction of the ribbed steel bar, and the angle β between the blowing direction of the third air knife and the running direction of the ribbed steel bar, are respectively consistent with the inclination angles on both sides of the transverse rib of the ribbed steel bar.

[0018] A further improvement of the present invention is that: a gas collection hood is provided outside the reduction sealing cover and the galvanized sealing cover, the gas collection hood is connected to the outside through an external exhaust pipe, a fan is installed on the external exhaust pipe, and a nitrogen gas alarm is installed inside the gas collection hood.

[0019] The beneficial effects of this invention are: This invention provides an oxygen-free online galvanizing device for hot-rolled ribbed steel bars. Surface treatment, galvanizing, and coating thickness control are all performed in a nitrogen atmosphere. The oxygen-free environment before and after galvanizing effectively avoids the harmful effects of oxygen on the steel bar substrate and coating. Furthermore, by replacing the original immersion galvanizing with online galvanizing, the limitation of steel bar length is solved, meeting the galvanizing requirements for ribbed steel bars of any length, including those over 10m in length. Moreover, this invention can simultaneously galvanize multiple ribbed steel bars arranged side-by-side, greatly improving galvanizing efficiency.

[0020] This invention employs interconnected reduction sealing hoods and galvanizing sealing hoods. The surface layer of high-temperature ribbed steel bars is reduced by mixing reducing gases, and then transported to the galvanizing unit for galvanizing in an inert gas atmosphere. The reduction, transportation, and galvanizing processes are all carried out in an oxygen-free environment, effectively avoiding oxidation of the steel bar surface and solving the problem of the impact of the steel bar oxide layer on the galvanizing quality.

[0021] In this invention, the reduction cylinder is filled with nitrogen and a mixed reducing gas, serving as the first level of protection; the reduction sealing cover and the galvanizing sealing cover are filled with nitrogen, serving as the second level of protection. This two-level protection, with its positive pressure setting, effectively isolates the ribbed steel bars from the outside air, ensuring that the high-temperature ribbed steel bars undergo reduction and galvanizing in an inert, oxygen-free environment. This improves the surface composition of the steel bars during galvanizing, resulting in a stronger and more stable bond between the coating and the steel bar substrate.

[0022] This invention's galvanizing mechanism, operating in an oxygen-free environment, uses a rotating lifting wheel to continuously elevate molten zinc to a high position and transfer it into a galvanizing tank. This allows the molten zinc to accumulate within the tank. When hot-rolled ribbed steel bars pass through the molten zinc-filled tank, the surface of the steel bars is coated, eliminating any dead zones. The galvanizing process is continuous, allowing for the simultaneous galvanizing of multiple ribbed steel bars. Furthermore, depending on the required zinc layer thickness, one or more molten zinc lifting mechanisms can be selected for operation, employing multi-layer coating to achieve a thicker coating. Compared to direct coating, the multi-layer, multi-coating process results in a coating with superior density and bonding strength to the substrate.

[0023] The galvanizing mechanism of this invention also includes two types of heating components: an auxiliary heater on the zinc pot, which effectively ensures the temperature and fluidity of the molten zinc; and an electric heating component located at the top of the galvanizing sealing tank, which radiates heat to the molten zinc flowing into the slag removal mechanism, preventing heat loss from the molten zinc, reducing the proportion of zinc slag, and maintaining good fluidity of the molten zinc in the galvanizing tank. Generally, multiple sets of auxiliary heaters and electric heating components are installed. The auxiliary heaters are evenly distributed along the length of the zinc pot, and the electric heating plates are arranged along the length of the galvanizing tank. The electric heating component is usually located above the molten zinc lifting mechanism to ensure uniform heating and good fluidity of the molten zinc.

[0024] This invention, after galvanizing, uses three continuously set air knives with different blowing angles to blow off excess molten zinc adhering to the surface of the reinforcing steel. The variation in blowing angle matches the protrusion angle of the transverse ribs on the surface of the ribbed reinforcing steel, ensuring a consistent coating thickness across all parts of the reinforcing steel surface. This is particularly effective at areas where molten zinc tends to accumulate, such as the junction of the transverse ribs and the steel body. The consistent coating thickness on the surface of the ribbed reinforcing steel ensures that control parameters such as the height of the transverse ribs meet relevant requirements, further guaranteeing the strength and other performance parameters of the ribbed reinforcing steel. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the main structure of the galvanizing mechanism; Figure 3 This is a side view of the galvanizing mechanism. Figure 4 This is a schematic diagram of the slag discharge assembly. Figure 5 This is a schematic diagram of the overall structure of the air knife mechanism; Figure 6 This is a side view of the air knife structure. Figure 7 This is a schematic diagram showing the included angle α of the first air knife nozzle. Figure 8 This is a schematic diagram showing the included angle β of the third air knife nozzle. In the diagram: 1. Reduction sealing cover; 1-1. Descaling device; 1-2. Purge air knife; 1-3. Reduction cylinder; 1-4. Nitrogen pipe at the beginning; 1-5. Nitrogen pipe at the end; 1-6. Mixed reducing gas branch pipe; 1-7. Distribution horizontal pipe; 1-8. Mixed reducing gas main pipe; 2. Galvanized sealing cover; 2-1. Discharge tower; 2-2. Electric heating assembly; 3. Transfer channel; 4. Escape pipe; 5. Ribbed steel bar; 6. Galvanized tank; 7. Zinc pot; 7-1. Auxiliary heater; 7-2. Liquid level window; 8-1. Elevator wheel; 8-2. Zinc bucket; 8-3. Tilting support block; 8-5. Suspension beam; 8-6. 9. Cantilever; 9. Slag discharge assembly; 9-1. Separation chamber; 9-2. Flow stabilization chamber; 9-3. Slag baffle; 9-4. Zinc slag outlet; 9-5. Zinc slag discharge trough; 10. Zinc liquid; 11. Trumpet mouth; 12. Zinc slag; 13-1. First air knife; 13-2. Second air knife; 13-3. Third air knife; 13-4. First guide groove; 13-5. Second guide groove; 13-6. Third guide groove; 13-7. Zinc liquid recovery tank; 13-8. Heating plate; 14. Air chamber; 15. Nozzle; 16. Compressed nitrogen pipe; 17. Gas collection hood; 17-1. External discharge pipe; 17-2. Fan. Detailed Implementation

[0026] The invention will now be further described with reference to the accompanying drawings.

[0027] An oxygen-free online galvanizing device for hot-rolled ribbed steel bars, such as Figures 1-8 As shown, the device includes a reduction sealing cover 1 and a galvanizing sealing cover 2 that are interconnected, as well as a reduction mechanism disposed within the reduction sealing cover 1, a galvanizing mechanism disposed within the galvanizing sealing cover 2, and an air knife mechanism. The outlet of the reduction sealing cover 1 and the inlet of the galvanizing sealing cover 2 are connected by a transfer channel 3, which is horizontally arranged. The ribbed steel bar 5 first enters the reduction sealing cover 1 for surface reduction, and then is horizontally pushed into the galvanizing sealing cover 2 through the transfer channel 3 for galvanizing.

[0028] Both the reduction sealing cover 1 and the galvanized sealing cover 2 are welded from steel plates. The front end of the reduction sealing cover 1 is provided with an inlet for the ribbed steel bar 5 to pass through, and the rear end of the galvanized sealing cover 2 is provided with an outlet for the ribbed steel bar 5 to exit. The rest of the parts are sealed.

[0029] The reduction mechanism includes a reduction cylinder 1-3, which is a horizontal elongated cylinder with a rectangular channel in the middle. The two ends of the reduction cylinder 1-3 are connected to a first-end nitrogen pipe 1-4 and a last-end nitrogen pipe 1-5, respectively. The first-end nitrogen pipe 1-4 and the last-end nitrogen pipe 1-5 pass through the reduction sealing cover 1 and are connected to a compressed nitrogen pipeline. Multiple mixed reducing gas inlets are arranged in parallel along the length of the reduction cylinder 1-3. These inlets converge into a distribution horizontal pipe 1-7 via mixed reducing gas branch pipes 1-6, and then connect to a mixed reducing gas source outside the reduction cylinder 1-3 via a mixed reducing gas main pipe 1-8. The nitrogen pressure introduced into the nitrogen pipe 1-4 at the beginning and the nitrogen pipe 1-5 at the end is greater than the pressure of the mixed reducing gas introduced in the middle, thereby sealing the mixed reducing gas in the middle of the reduction cylinder 1-3 and preventing it from easily leaking out. When the ribbed steel bar 5 passes through the reduction cylinder 1-3, the hot steel bar surface comes into contact with the reducing gas and the surface oxides undergo a reduction reaction, the surface oxides are removed, and the steel substrate is exposed.

[0030] The mixed reducing gas is a nitrogen-hydrogen mixture, with a hydrogen content of 5% to 8%. Excessive hydrogen content increases the risk of explosion, while insufficient hydrogen content fails to ensure adequate reduction of the steel reinforcement surface. Experiments have shown that a hydrogen content of 5% to 8% is sufficient for reducing a small amount of thin iron oxide scale on the surface of the ribbed steel reinforcement 5. For the reduction of thicker iron oxide scale, the hydrogen content can be appropriately increased based on the scale content, and an auxiliary heater can be added upstream of the reduction cylinder 1-3 to appropriately raise the temperature of the ribbed steel reinforcement 5, ensuring effective reduction.

[0031] To ensure the full reduction of iron oxide scale on the surface of the reinforcing bars, a descaling and dewatering device 1-1 is also installed inside the reduction sealing cover 1. The descaling and dewatering device 1-1 is located upstream of the reduction mechanism. The ribbed reinforcing bars 5, after surface cleaning, enter the reduction sealing cover 1, are first further cleaned and dried by the descaling and dewatering device 1-1, and then enter the reduction mechanism to fully reduce the trace oxides generated on the surface of the reinforcing bars. Finally, they are sent to the galvanizing mechanism for direct galvanizing.

[0032] The descaling and dewatering device 1-1 has a rectangular box-like structure with horizontally opened channels inside to accommodate multiple parallel ribbed steel bars 5. A purge air knife 1-2 is installed at both the top and bottom of the device 1-1. The purge air knife 1-2 is connected to a high-pressure nitrogen pipe, and the spray direction of the purge air knife 1-2 is at a 45° angle to the horizontal. Through the inclined purge of high-pressure nitrogen, trace amounts of oxide scale and moisture on the surface of the ribbed steel bars 5 are removed. The airflow channel inside the purge air knife 1-2 gradually narrows to ensure the pressure and purging effect of the purge nitrogen.

[0033] The top of the reduction sealing cover 1 and the top of the galvanized sealing cover 2 are connected by an escape pipe 4. One end of the escape pipe 4 is located on the reduction sealing cover 1 between the mixed reducing gas main pipe 1-8 and the tail nitrogen pipe 1-5, and the other end is connected to the front end of the galvanized sealing cover 2. Nitrogen gas introduced through the head nitrogen pipe 1-4 and the tail nitrogen pipe 1-5, as well as the mixed reducing gas, enter the galvanized sealing cover 2 through the transfer channel 3 and the escape pipe 4, respectively, to maintain an oxygen-free inert environment inside the galvanized sealing cover 2, ensuring that the ribbed steel bars 5 are in an inert atmosphere before and during galvanizing, and that their surface does not oxidize. An exhaust tower 2-1 is installed at the tail end of the galvanized sealing cover 2, through which nitrogen and trace amounts of hydrogen gas are discharged to a higher position.

[0034] Generally, the nitrogen pressure introduced into the nitrogen pipes 1-4 at the beginning and 1-5 at the end is 0.3 kg, the pressure of the mixed reducing gas introduced into the middle of the reduction cylinder 1-3 is 0.2 kg, and the nitrogen pressure introduced into the descaling and dewatering device 1-1 is 7-8 kg. The gas pressure can be adjusted adaptively during actual production.

[0035] The working principle of the reduction mechanism is as follows: In the reduction cylinder, the nitrogen gas introduced at both ends has a higher pressure than the mixed reducing gas introduced in the middle, sealing the mixed reducing gas in the middle of the cylinder and preventing hydrogen from escaping and reducing the hydrogen content. When the ribbed steel bars pass through the reducing atmosphere in the middle of the reduction cylinder, the oxides react with the hydrogen. As the gas is continuously introduced into the reduction cylinder, nitrogen (containing trace amounts of hydrogen that did not participate in the reduction reaction) gradually fills the reduction sealing hood, and enters and fills the galvanizing sealing hood through the transfer channel and the escape pipe, so that the galvanizing process is also carried out in an inert gas atmosphere, effectively isolating the ribbed steel bars from the influence of oxygen.

[0036] In addition, the nitrogen gas introduced into the descaling and dewatering device is at a pressure of 7-8 kg, and the inlet end of the reduction sealing cover is sealed to prevent air from entering the reduction sealing cover.

[0037] In summary, the reduction cylinder is filled with nitrogen and a nitrogen-hydrogen mixture, providing the first level of protection; the reduction sealing cover and the galvanized sealing cover are filled with nitrogen, providing the second level of protection. Relative to the outside environment, the reduction sealing cover / galvanized sealing cover and the reduction cylinder are all under positive pressure, effectively isolating them from air.

[0038] The zinc plating mechanism, such as Figures 2-4 As shown, it includes a galvanizing tank 6, a zinc pot 7, and a zinc liquid lifting assembly. The galvanizing mechanism is housed within a nitrogen-filled, positive-pressure galvanizing sealed enclosure 2, and the galvanizing process is carried out in an oxygen-free environment.

[0039] Normally, before galvanizing, the air inside the galvanizing sealing cover 2 needs to be replaced. Through one or more replacements, it is ensured that the air inside the galvanizing sealing cover 2 has been completely replaced by nitrogen before the normal galvanizing operation can be carried out.

[0040] The top of the galvanizing sealing tank 2 is equipped with an electric heating component 2-2, which can provide auxiliary heat during the galvanizing process, prevent the loss of heat from the zinc liquid 10, avoid the generation of zinc dross, and maintain the temperature of the zinc liquid 10 between 450℃ and 480℃. It has good fluidity and can be fully coated and film-formed on the surface of the hot-rolled ribbed steel bar 5.

[0041] The zinc pot 7 contains molten zinc 10. An auxiliary heater 7-1 is also installed on the zinc pot 7 to ensure the molten zinc 10 remains liquid and has good fluidity. The number of auxiliary heaters 7-1 is determined by the length of the zinc pot 7, and the auxiliary heaters 7-1 are typically arranged along the length of the zinc pot 7. The zinc pot 7 is also equipped with a level window 7-2 for monitoring the flow and level of the molten zinc 10, allowing for timely replenishment of the molten zinc 10.

[0042] A galvanizing tank 6 is arranged parallel to the zinc pot 7 along its length. The galvanizing tank 6 is a long strip with horizontally opened channels inside. A zinc liquid lifting assembly is provided on one side of the galvanizing tank 6 to lift and pour the zinc liquid 10 in the zinc pot 7 into the galvanizing tank 6. A slag discharge assembly is provided on the opposite side of the zinc liquid lifting assembly to remove zinc dross from the zinc liquid 10. Multiple hot-rolled ribbed steel bars 5 enter the galvanizing tank 6 side by side. As the hot-rolled ribbed steel bars 5 are conveyed forward, they come into contact with the zinc liquid 10 in the galvanizing tank 6 and complete the surface coating.

[0043] The length of the galvanizing tank 6 is less than the length of the zinc pot 7, so that when the molten zinc 10 flows out from the openings at both ends of the galvanizing tank 6, it falls directly into the zinc pot 7.

[0044] The zinc liquid lifting assembly includes a lifting wheel 8-1, a zinc bucket 8-2, a tilting support block 8-3, and a lifting motor for driving the lifting wheel 8-1 to rotate. The lifting wheel 8-1 is a rotary supported circular wheel. The power output shaft of the lifting motor is connected to a reducer, and the power output shaft of the reducer is connected to the wheel core of the lifting wheel 8-1 through a transmission connection. The lifting motor drives the lifting wheel 8-1 to rotate. A shaft balancer is also provided between the lifting motor and the wheel core of the lifting wheel 8-1 to ensure the constant speed and stable rotation of the lifting wheel 8-1.

[0045] It should be noted that, due to the high temperature of the zinc pot, in order to ensure the stable rotation of the hoist wheel, the hoist motor, reducer, and shaft balancer are all installed outside the galvanized sealing cover 2, and a cooling protection cover is installed around it to prevent the hoist motor from overheating.

[0046] Several zinc buckets 8-2 are connected to the lifting wheel 8-1. The zinc buckets 8-2 are evenly distributed circumferentially around the axis of the lifting wheel 8-1. When the zinc buckets 8-2 rotate into the zinc pot 7, they are filled with molten zinc 10 and lifted to a high position. The lifting wheel 8-1 is also equipped with a tilting support block 8-3 for gradually tilting the zinc buckets 8-2 that have been turned out of the zinc pot 7 toward the galvanizing tank 6.

[0047] like Figure 3 As shown, the hoist wheel 8-1 is provided with several suspension beams 8-5 evenly distributed around its circumference. The suspension beams 8-5 are perpendicular to the wheel body of the hoist wheel 8-1 and extend towards one side of the galvanizing tank 6. The zinc bucket 8-2 is hinged to the suspension beams 8-5 through two cantilever arms 8-6. The zinc bucket 8-2 is also hinged to the cantilever arms 8-6 on both sides through hinge shafts. When the hoist wheel 8-1 rotates, the zinc bucket 8-2 rotates with the suspension beams 8-5 as the axis, so that the opening of the zinc bucket 8-2 always faces upward.

[0048] One side of the elevator wheel 8-1 is also provided with a tilting support block 8-3 for gradually tilting the zinc bucket 8-2 during its upward lifting process until it tilts horizontally. The tilting support block 8-3 is fixedly mounted on the elevator wheel 8-1 and does not rotate with the elevator wheel 8-1. The tilting support block 8-3 is typically located in the area between the zinc bucket 8-2 exiting the zinc pot 7 and the zinc bucket 8-2 reaching its highest point. Figure 4As shown, the tilting support block 8-3 is a fan-shaped wedge with a central angle of 90° and a sloping top surface. The inclination angle of the top sloping surface of the tilting support block 8-3 gradually decreases from bottom to top, and the zinc bucket 8-2 contacts the top sloping surface of the tilting support block 8-3. The bottom of the zinc bucket 8-2 is arc-shaped. When the zinc bucket 8-2 is lifted upward from the galvanizing tank 6, the bottom of the zinc bucket 8-2 contacts the tilting support block 8-3 and is tilted along the hinge axis of the cantilever 8-6 due to the upward thrust of the tilting support block 8-3. As the lifting wheel 8-1 rotates, the inclination angle of the zinc bucket 8-2 gradually increases until it reaches the top of the lifting wheel 8-1, at which point the zinc bucket 8-2 becomes horizontal and pours the molten zinc 10 into the galvanizing tank 6. Subsequently, the zinc bucket 8-2 continues to descend under the action of the lifting wheel 8-1 and releases the support from the tilting support block 8-3. The zinc bucket 8-2 returns to its original position under the action of gravity, and the lifting and transfer of the molten zinc 10 is repeated.

[0049] The other side of the galvanizing tank 6 is provided with a slag discharge assembly 9 corresponding to the top of the elevator wheel 8-1. For example... Figure 3 As shown, the slag discharge mechanism 9 includes a separation chamber 9-1 and a flow stabilizing chamber 9-2 arranged side by side and connected at the bottom. The height of the connection between the separation chamber 9-1 and the flow stabilizing chamber 9-2 is adjusted by a slag baffle plate 9-3. The top of the separation chamber 9-1 is open and corresponds to the tilting point of the zinc bucket 8-2 of the elevator wheel 8-1. The top of the separation chamber 9-1 is provided with a zinc slag outlet 9-4 connected to the zinc slag discharge trough 9-3. The bottom of the flow stabilizing chamber 9-2 is connected to the galvanizing tank 6. The zinc liquid in the zinc bucket 8-2 flows in through the top opening of the separation chamber 9-1. Under the action of gravity, the zinc slag 12 floats on the surface of the zinc liquid 10 and enters the zinc slag discharge trough 9-5 through the zinc slag outlet 9-4. After collection and purification, it is reused as galvanizing liquid. The zinc liquid 10 enters the flow stabilizing chamber 9-2 through the connection and flows into the galvanizing tank 6 through the outlet at the bottom of the flow stabilizing chamber 9-2, where it coats multiple hot-rolled ribbed steel bars 5. During the flow of molten zinc, based on the principle of communicating vessels, the stabilizing chamber 9-2 can maintain a certain liquid level, and can maintain a stable flow of molten zinc even during the pouring intervals of zinc hopper 8-2, ensuring the height of molten zinc in galvanizing tank 6 and the galvanizing effect of ribbed steel bars.

[0050] A vertical slot is provided between the separation chamber 9-1 and the flow stabilizing chamber 9-2. A slag baffle 9-3 is inserted into the slot, forming a flow channel for the molten zinc between the slag baffle 9-3 and the bottom of the separation chamber 9-1. The slag baffle 9-3 can be fixed to the top of the flow stabilizing chamber 9-2 with pins. In this case, the slag baffle 9-3 is a fixed slag baffle, and the flow speed of the molten zinc is not adjustable. The position of the slag baffle 9-3 can also be adjusted by a pneumatic regulating cylinder. Specifically, a pneumatic regulating cylinder is installed on the top of the galvanized sealing cover 2. The front end of the pneumatic rod of the pneumatic regulating cylinder is connected to the top of the slag baffle. The height of the slag baffle 9-3 is controlled by the extension and retraction of the pneumatic rod, thereby adjusting the height of the flow channel between the slag baffle 9-3 and the bottom of the separation chamber 9-1.

[0051] During use, multiple sets of zinc liquid lifting components and slag removal components can be sequentially set according to the required zinc coating thickness on the surface of the ribbed steel bar 5, such as the two sets shown in the figure. A multi-layer coating method is used to achieve a thicker coating. Compared with direct coating, the coating after multiple layers has better density and stronger adhesion to the substrate.

[0052] The galvanized sealing cover 2 is also equipped with an air knife mechanism for controlling the zinc layer thickness of the galvanized ribbed steel bar 5. For example... Figure 5 As shown, the air knife mechanism includes a first air knife 13-1, a second air knife 13-2, and a third air knife 13-3 sequentially arranged downstream of the galvanizing tank 6. The first air knife 13-1, the second air knife 13-2, and the third air knife 13-3 are all hollow "U"-shaped structures. Corresponding conveying channels for the hot-rolled ribbed steel bars 5 to pass through are opened inside the first air knife 13-1, the second air knife 13-2, and the third air knife 13-3, forming an air cavity 14 between the conveying channels and the outer wall of the air knife. The top and bottom of the air cavity 14 are respectively connected to compressed nitrogen pipes 16.

[0053] Several nozzles 15 are arranged around the perimeter of the conveying channel. The nozzles 15 are connected to the air chamber 14, and all nozzles 15 face the center of the conveying channel. Compressed nitrogen gas is simultaneously sprayed out from the multiple nozzles 15 through the air chamber 14 to thoroughly purge the surface of the galvanized hot-rolled ribbed steel bar 5 during conveying, removing excess zinc liquid.

[0054] like Figure 7 , Figure 8 As shown, the blowing direction of the nozzle 15 of the first air knife 13-1 is inclined towards the running direction of the ribbed steel bar 5, and the angle α between the blowing direction of the nozzle 15 of the first air knife 13-1 and the running direction of the ribbed steel bar 5 is 130°~150°; the blowing direction of the nozzle 15 of the second air knife 13-2 is perpendicular to the running direction of the ribbed steel bar 5; the blowing direction of the nozzle 15 of the third air knife 13-3 is inclined against the running direction of the ribbed steel bar 5, and the angle β between the blowing direction of the nozzle 15 of the third air knife 13-3 and the running direction of the ribbed steel bar 5 is 40°~50°. By blowing with air knives at three different angles, excess zinc liquid adhering to the surface of the transverse ribs of the ribbed steel bar 5 is blown away. The angle between the blowing direction of the nozzle of the first air knife 13-1 / the blowing direction of the nozzle of the third air knife 13-3 and the running direction of the ribbed steel bar 5 can be adjusted according to the size of the transverse ribs of the ribbed steel bar 5 to make it consistent with the inclination angle of the transverse rib surface.

[0055] To ensure the stable forward transport of galvanized hot-rolled ribbed steel bars 5, a first guide groove 13-4 is provided between the first air knife 13-1 and the second air knife 13-2, a second guide groove 13-5 is provided between the second air knife 13-2 and the third air knife 13-3, and a third guide groove 13-6 is provided at the rear end of the third air knife 13-3.

[0056] Preferably, since the hot-rolled ribbed steel bars 5 are arranged side by side and conveyed forward synchronously, in order to ensure the effectiveness of the zinc removal solution blowing, the number of nozzles 15 located above and below is not less than the number of ribbed steel bars 5, and they are evenly distributed along the width direction to ensure that the surfaces of multiple ribbed steel bars 5 are synchronously blown. The number of nozzles 15 located on both sides of the ribbed steel bars 5 is preferably two.

[0057] Below the first air knife 13-1, the second air knife 13-2, and the third air knife 13-3, a zinc liquid recovery tank 13-7 is also provided, which is directly connected to the zinc pot 7. The zinc liquid blown off by the air knives falls into the zinc liquid recovery tank 13-7, is enriched, and then returned to the zinc pot 7 for reuse.

[0058] To prevent dripping molten zinc from solidifying in the zinc recovery tank 13-7 and becoming unrecoverable, a heating plate 13-8 is installed at the bottom of the zinc recovery tank 13-7. While maintaining the molten zinc in a liquid state, the zinc recovery tank 13-7 also affects the temperature of the galvanized ribbed steel bars 5 passing above it, keeping the galvanized ribbed steel bars 5 at a constant temperature and preventing the coating from cooling and solidifying prematurely, which would affect the subsequent air knife purging control of the coating.

[0059] To facilitate the return of zinc liquid in the zinc liquid recovery tank 13-7, the bottom of the zinc liquid recovery tank 13-7 is set to be inclined towards the zinc pot 7.

[0060] Since the hot-rolled ribbed steel bars 5 are arranged in multiple parallel rows and conveyed forward synchronously, in order to laterally constrain and straighten the ribbed steel bars 5 so that they can be conveyed smoothly and continuously without steel piling up, the inlet ends of the reduction cylinder, descaling device, galvanizing tank 6, first guide channel 13-4, second guide channel 13-5, and third guide channel 13-6 are all connected to a flared mouth 11 that is larger at the front and smaller at the back. This is used to laterally constrain and feed the multiple ribbed steel bars 5 into the box and convey them continuously, so as to avoid steel piling up.

[0061] The reduction sealing cover 1 and the galvanized sealing cover 2 are further equipped with a gas collection cover 17, which completely covers the reduction sealing cover 1 and the galvanized sealing cover 2. The emission tower 2-1 passes through the gas collection cover 17 and is connected to the outside. The gas collection cover 17 is connected to the outside through an external exhaust pipe 17-1, on which a fan 17-2 is installed. A nitrogen gas alarm is installed inside the gas collection cover 17. The nitrogen gas alarm and the fan 17-2 are controlled in coordination through a PLC control terminal. Although most of the nitrogen in the reduction sealing cover 1 and the galvanized sealing cover 2 is discharged by the emission tower 2-1, nitrogen leakage between various equipment and between equipment is still inevitable. If the nitrogen concentration is too high, it will cause harm to workers. Therefore, a nitrogen gas alarm is used to monitor the nitrogen concentration in the plant. When the nitrogen concentration in the exhaust exceeds the standard and triggers the nitrogen gas alarm, the fan 17-2 will automatically start to exhaust the air in the plant and reduce the nitrogen concentration.

[0062] The working process of this invention is as follows: Hot-rolled ribbed steel bars, after surface treatment, enter the reduction unit. First, a descaling device removes loose iron oxide scale from the surface of the ribbed steel bars. Then, they enter the reduction cylinder, where a high-temperature reduction reaction occurs under the action of hydrogen, reducing and removing any remaining trace oxides on the surface of the ribbed steel bars. The cleaned ribbed steel bars then enter the galvanizing unit within a sealed galvanizing hood under a nitrogen atmosphere.

[0063] As the elevator wheel rotates continuously, the zinc bucket is submerged in the zinc pot to hold molten zinc. During the upward lifting process, it is gradually tilted by the tilting support block. When it reaches the top of the elevator wheel, the zinc bucket tilts to the horizontal. The molten zinc in the zinc bucket flows into the slag discharge mechanism. The molten zinc after separating the zinc slag flows into the galvanizing tank to coat the hot-rolled ribbed steel bars passing through it. Excess molten zinc flows into the zinc pot from both ends of the galvanizing tank.

[0064] After galvanizing, the ribbed steel bars enter the air knife mechanism, where they are sprayed in three directions by the first, second, and third air knives to remove excess zinc, ensuring a uniform zinc layer thickness on the surface of the ribbed steel bars. After cooling, the zinc layer solidifies, resulting in galvanized ribbed steel bars. The excess zinc removed by the air knives flows back into the zinc pot through a zinc recovery tank.

[0065] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for oxygen-free online galvanizing of hot-rolled ribbed steel bars, characterized in that: It includes a reduction sealing cover (1) and a galvanized sealing cover (2) connected by a transfer channel (3), as well as a reduction mechanism set in the reduction sealing cover (1), a galvanizing mechanism and an air knife mechanism set in the galvanized sealing cover (2); the front end of the reduction sealing cover (1) is provided with an inlet for the ribbed steel bar (5) to pass through, and the rear end of the galvanized sealing cover (2) is provided with an outlet for the ribbed steel bar (5) to exit. The reduction mechanism includes a horizontally arranged reduction cylinder (1-3) with a rectangular channel running through its interior. The two ends of the reduction cylinder (1-3) are connected to a first-end nitrogen pipe (1-4) and a last-end nitrogen pipe (1-5), respectively. The first-end nitrogen pipe (1-4) and the last-end nitrogen pipe (1-5) pass through the reduction sealing cover (1) and are connected to a compressed nitrogen pipeline. Multiple mixed reducing gas inlets are arranged in parallel along the length of the middle of the reduction cylinder (1-3). The mixed reducing gas inlets are connected to a mixed reducing gas source outside the reduction cylinder (1-3). The nitrogen pressure introduced into the first-end nitrogen pipe (1-4) and the last-end nitrogen pipe (1-5) is greater than the mixed reducing gas pressure introduced into the mixed reducing gas inlet. The galvanizing mechanism includes a galvanizing tank (6), a zinc pot (7), and a zinc liquid lifting assembly. The zinc pot (7) contains molten zinc liquid. The galvanizing tank (6) is horizontally arranged above the zinc pot (7) along its length. A zinc liquid lifting assembly is provided on one side of the galvanizing tank (6) to lift the zinc liquid (10) in the zinc pot (7) to a high position and pour it into the galvanizing tank (6). The zinc liquid lifting assembly includes a lifting wheel (8-1), zinc buckets (8-2), a tilting support block (8-3), and a lifting motor for driving the lifting wheel (8-1) to rotate. The lifting wheel (8-1) is a rotary-supported circular wheel. Several zinc buckets (8-2) are connected circumferentially along the axis of the lifting wheel (8-1). The zinc buckets (8-2) can be immersed in the zinc pot (7) as the lifting wheel (8-1) rotates and lift the zinc liquid (10) to a high place for transfer. The lifting wheel (8-1) is also provided with a tilting support block (8-3) for gradually tilting the zinc buckets (8-2) lifted out of the zinc pot (7) toward the galvanizing tank (6). On the opposite side of the zinc liquid lifting assembly, a slag discharge assembly (9) for removing zinc dross from the zinc liquid (10) is also provided.

2. The oxygen-free online galvanizing device for hot-rolled ribbed steel bars according to claim 1, characterized in that: The mixed reducing gas is a nitrogen mixture, wherein the hydrogen content is 5% to 8%.

3. The oxygen-free online galvanizing device for hot-rolled ribbed steel bars according to claim 1, characterized in that: The reduction sealing cover (1) is also equipped with a descaling device (1-1); the descaling device (1-1) is located upstream of the reduction mechanism.

4. The oxygen-free online galvanizing device for hot-rolled ribbed steel bars according to claim 1, characterized in that: The top of the reduction sealing cover (1) and the top of the galvanized sealing cover (2) are also connected by an escaping pipe (4), and the tail end of the galvanized sealing cover (2) is provided with an exhaust tower (2-1) for high-altitude nitrogen exhaust.

5. The oxygen-free online galvanizing device for hot-rolled ribbed steel bars according to claim 1, characterized in that: The air knife mechanism includes a first air knife (13-1), a second air knife (13-2), and a third air knife (13-3) sequentially arranged downstream of the galvanizing tank (6); the first air knife (13-1), the second air knife (13-2), and the third air knife (13-3) are all "return" - shaped hollow structures, and nozzles (15) connected to their internal air cavities (14) are further provided on the first air knife (13-1), the second air knife (13-2), and the third air knife (13-3); the blowing direction of the first air knife (13-1) is inclined towards the running direction of the ribbed steel bar (5), the blowing direction of the second air knife (13-2) is perpendicular to the running direction of the ribbed steel bar (5), and the blowing direction of the third air knife (13-3) is inclined in the reverse direction of the running direction of the ribbed steel bar (5).

6. The oxygen-free online galvanizing device for hot-rolled ribbed steel bars according to claim 5, characterized in that: The included angle α between the blowing direction of the first air knife (13-1) and the running direction of the ribbed steel bar (5), and the included angle β between the blowing direction of the third air knife (13-3) and the running direction of the ribbed steel bar (5) are respectively consistent with the inclination angles on both sides of the transverse rib of the ribbed steel bar (5).

7. The oxygen-free online galvanizing device for hot-rolled ribbed steel bars according to claim 6, characterized in that: An air collecting hood (17) is further provided outside the reduction sealing cover (1) and the galvanizing sealing cover (2). The air collecting hood (17) is communicated with the outside through an exhaust pipe (17-1), a blower (17-2) is installed on the exhaust pipe (17-1), and a nitrogen gas alarm is arranged inside the air collecting hood (17).

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