Zinc ash extraction device and extraction method in zinc boiler nose of hot galvanizing unit

Abstract

The application relates to a zinc-ash extraction device and method in a zinc boiler nose of a hot galvanizing unit, which comprises an electromagnetic pump, a liquid metal loop arranged in the electromagnetic pump, one end of the liquid metal loop being provided with a zinc liquid inlet pipeline (1), the other end being provided with a zinc liquid outlet pipeline (2), the zinc liquid outlet pipeline (2) being provided with a pump filling valve (3), a vacuum extraction pipeline being arranged on the zinc liquid outlet pipeline (2) between the pump filling valve (3) and the electromagnetic pump, and the vacuum extraction pipeline being provided with a sealing valve (5). Compared with the prior art, the application provides a zinc-ash extraction device in a zinc boiler nose of a hot galvanizing unit, which adopts negative pressure pre-filling to solve the problem that the electromagnetic pump is difficult to self-suck when being installed at a high position, so that the electromagnetic pump can be reliably started in a full-liquid state.

Description

Technical Field

[0001] This invention relates to the field of hot-dip galvanizing technology for metal strips, specifically to a zinc ash extraction device and method for the zinc boiler nose of a hot-dip galvanizing unit. Background Technology

[0002] In the continuous hot-dip galvanizing process of cold-rolled strip steel, the furnace nose is a crucial gas-sealing component connecting the continuous annealing furnace and the zinc pot. After annealing, the strip steel enters the zinc pot through the furnace nose under a reducing protective atmosphere to complete the hot-dip galvanizing. Due to the high temperature of the zinc liquid and the presence of zinc vapor, trace amounts of oxygen, and atmospheric disturbances in the furnace nose area, zinc ash, mainly composed of zinc oxide, easily forms on the surface of the zinc liquid inside the furnace nose. If the zinc ash is not removed in time, it can easily be drawn into or adhere to the surface of the moving strip steel, resulting in surface quality defects such as black spots, inclusions, incomplete galvanizing, and uneven coating thickness.

[0003] Current production methods typically employ mechanical zinc pumps, manual slag removal, or periodic shutdowns for cleaning to remove zinc ash from the furnace nose. However, mechanical zinc pumps, operating for extended periods in a zinc molten environment at approximately 450°C to 460°C, are susceptible to high-temperature corrosion and wear on their moving parts, such as seals, bearings, and impellers, leading to short maintenance cycles, high spare parts consumption, and a high risk of downtime. Manual slag removal or intermittent cleaning struggles to achieve continuous dynamic capture of zinc ash within the confined space of the furnace nose and can easily introduce surface disturbances, affecting the stability of the strip coating.

[0004] Electromagnetic pumps utilize electromagnetic force to directly drive the flow of conductive liquid metal. They offer advantages such as no rotating impeller, no shaft seal, high temperature resistance, and low maintenance, making them suitable for circulating zinc liquid. However, the effective operation of an electromagnetic pump requires the flow channel to be filled with conductive liquid metal. When the electromagnetic pump is installed above the zinc pot's liquid level or when residual gas exists in the pipeline, it is difficult for the pump to self-prime, and problems such as no-load operation, localized overheating, or unstable flow may occur.

[0005] Therefore, there is an urgent need for a device that can reliably establish a full liquid state in the furnace nose area and continuously, stably, and with low disturbance extract zinc ash in the full liquid state. Summary of the Invention

[0006] The purpose of this invention is to overcome at least one of the defects of existing traditional zinc ash cleaning equipment and processes, such as high-temperature vulnerability, inability to operate continuously, difficulty in self-priming of electromagnetic pumps, and large liquid surface disturbance, and to provide a zinc ash extraction device and extraction method for the zinc boiler nose of a hot-dip galvanizing unit.

[0007] The objective of this invention can be achieved through the following technical solutions: One objective of this invention is to provide a zinc ash extraction device for the zinc boiler nose of a hot-dip galvanizing unit, comprising: Electromagnetic pump; A liquid metal circuit is installed inside the electromagnetic pump. One end of the liquid metal circuit is provided with a zinc liquid inlet pipe, and the other end is provided with a zinc liquid outlet pipe. A priming valve is installed on the zinc liquid outlet pipe. A vacuum line is installed on the zinc liquid outlet pipeline between the filling pump valve and the electromagnetic pump, and a sealing valve is installed on the vacuum line.

[0008] Furthermore, the electromagnetic pump is an induction electromagnetic pump or a conduction electromagnetic pump; when the electromagnetic pump is an induction electromagnetic pump, its operating frequency is 30Hz to 100Hz and its magnetic field strength is 0.1T to 1.5T. The electromagnetic pump is positioned above the liquid surface of the zinc pot, and there is a vertical height difference between the electromagnetic pump and the liquid surface of the zinc pot; the rated head of the electromagnetic pump is 0.5m to 5m, and the rated head is greater than the vertical height difference.

[0009] Furthermore, the electromagnetic pump includes an inner iron core, a coil, an outer iron core, and a heat-insulating outer shell arranged from the inside out.

[0010] Furthermore, the liquid metal circuit is formed by a metal pipe sleeved on the inner iron core and the inner iron core; The outer diameter of the metal pipe is 150mm to 300mm, and the wall thickness is 5mm to 12mm.

[0011] Furthermore, the heat-insulating outer shell includes an inner layer and an outer layer arranged from the inside out.

[0012] Furthermore, the outer interlayer is provided with nozzles, which are used to evacuate the inner and outer interlayers to form a vacuum insulation layer.

[0013] Furthermore, the space between the inner and outer interlayers is filled with a high-temperature resistant insulating medium.

[0014] Furthermore, the liquid metal circuit is also equipped with a liquid level detection device and a temperature control sensor.

[0015] The second objective of this invention is to provide a method for extracting zinc ash from the zinc boiler nose of a hot-dip galvanizing unit, which employs the device described above and includes the following steps: S1. Open the vacuum cylinder in the vacuum device and put the filling pump valve and the sealing valve into the vacuum connection state to evacuate the liquid metal circuit, so that the zinc liquid in the zinc pot enters the liquid metal circuit through the zinc liquid inlet pipe. S2. Determine whether the liquid metal circuit has reached the preset full state through the liquid level detection device; S3. When the liquid metal circuit reaches the preset full state, close or switch the negative pressure passage and start the electromagnetic pump. S4. The zinc liquid is driven by an electromagnetic pump to circulate in the liquid metal circuit, and the zinc liquid containing zinc ash in the furnace nose area is extracted and returned to the zinc pot through the zinc liquid outlet pipeline.

[0016] Furthermore, in step S4, the excitation frequency or current of the electromagnetic pump is adjusted according to the temperature signal detected by the temperature control sensor to maintain the zinc liquid temperature at 445°C to 470°C.

[0017] Compared with the prior art, the present invention has the following advantages: (1) The present invention provides a zinc ash extraction device in the nose of the zinc boiler of a hot-dip galvanizing unit. The device uses negative pressure pre-filling to solve the problem that the electromagnetic pump is difficult to self-prime when it is installed at a high position, so that the electromagnetic pump can be reliably started in a full liquid state.

[0018] (2) The present invention provides a zinc ash extraction device in the nose of the zinc boiler of a hot-dip galvanizing unit. The device uses electromagnetic drive to replace the traditional mechanical impeller drive, which reduces the wear of shaft seals, bearings and impellers, improves equipment life and reduces maintenance costs.

[0019] (3) The present invention provides a zinc ash extraction device in the nose of the zinc boiler of a hot-dip galvanizing unit. The device realizes the monitoring of start-up and operation status through liquid level detection and temperature feedback, thereby reducing the risk of idling, overheating and severe disturbance.

[0020] (4) The present invention provides a zinc ash extraction device inside the zinc boiler nose of a hot-dip galvanizing unit. The device reduces heat conduction through a heat-insulating shell, which is beneficial to protect the coil and maintain the thermal stability of the zinc liquid.

[0021] (5) The present invention provides a method for extracting zinc ash from the nose of a hot-dip galvanizing unit zinc boiler. This method can realize the continuous extraction of zinc ash from the nose of the boiler and reduce the probability of surface quality defects of the strip steel. Attached Figure Description

[0022] Figure 1 This is a cross-sectional schematic diagram of the electromagnetic pump in this invention; Figure 2 This is a schematic diagram of the three-dimensional equiaxial operation of zinc ash extraction from the zinc boiler nose in this invention.

[0023] The numbers in the diagram indicate: 1-Inlet zinc liquid pipeline; 2-Outlet zinc liquid pipeline; 3-Pouring pump valve; 4-Evacuation device; 5-Sealing valve; 6-Coil; 7-Outer iron core; 8-Inner iron core; 9-Insulation shell; 10-Furnace nose; 11-Zinc pot; 12-Strip steel. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0025] Example 1 Please see Figure 1-2 This embodiment provides a zinc ash extraction device from the zinc boiler nose of a hot-dip galvanizing unit, including an electromagnetic pump, a liquid metal circuit, and a vacuum pipeline.

[0026] The liquid metal circuit is housed within the electromagnetic pump, with a zinc inlet pipe 1 at one end and a zinc outlet pipe 2 at the other end. A filling valve 3 is installed on the zinc outlet pipe 2. The liquid metal circuit also includes a liquid level detection device and a temperature control sensor. The liquid level detection device is preferably an electromagnetic type, used to detect the zinc filling status. The temperature control sensor detects the operating temperature, providing a basis for adjusting process parameters.

[0027] The vacuuming pipeline is installed on the zinc liquid outlet pipeline 2 between the filling pump valve 3 and the electromagnetic pump, and a sealing valve 5 is installed on it.

[0028] In this embodiment, the electromagnetic pump is positioned above the liquid surface of the zinc pot, and there is a vertical height difference between the electromagnetic pump and the liquid surface of the zinc pot; the rated head of the electromagnetic pump is 0.5m to 5m, and the rated head is greater than the vertical height difference.

[0029] In this embodiment, the electromagnetic pump includes an inner iron core 8, a coil 6, an outer iron core 7, and a heat-insulating shell 9 arranged from the inside out. Specifically, the heat-insulating shell 9 is formed by bolting an outer encapsulation tube wall to a cover. The coil 6 and the outer iron core 7 are disposed inside the encapsulation shell, and the inner iron core 8 is arranged along the central axis of the electromagnetic pump. The two ends of the inner iron core 8 are supported and fixed by a supporting encapsulation assembly, maintaining a stable gap between the inner iron core 8 and the outer iron core 7, thereby improving the consistency of the magnetic field distribution during the operation of the electromagnetic pump.

[0030] In this embodiment, the liquid metal circuit is formed by a metal pipe sleeved on the inner iron core 8 and the inner iron core 8, so as to allow the high-temperature zinc liquid to pass through; the outer diameter of the metal pipe is 150mm to 300mm and the wall thickness is 5mm to 12mm.

[0031] In this embodiment, the heat insulation shell 9 includes an inner layer and an outer layer arranged from the inside out. That is, the heat insulation shell 9 adopts a double-layer structure, and nozzles can be installed on the double-layer structure. Before the device is put into operation, the double-layer structure can be evacuated through the nozzles to form a vacuum insulation layer, or a high-temperature resistant heat insulation medium can be filled into the double-layer structure to reduce the thermal impact of high-temperature zinc liquid on the coil 6.

[0032] The method for extracting zinc ash from the zinc boiler nose of a hot-dip galvanizing unit using the device provided in this embodiment includes the following steps: Before starting the equipment, keep the filling pump valve 3 and sealing valve 5 fully open and conductive, that is, keep the filling pump valve 3 and sealing valve 5 in a vacuum connection state. Turn on the vacuum cylinder of the vacuum pumping device 4 to create a negative pressure vacuum in the liquid metal circuit. Relying on the negative pressure siphon effect, the zinc liquid in the zinc pot 11 automatically fills the entire liquid metal circuit through the zinc liquid inlet pipe 1. The liquid level detection device provides real-time feedback of the liquid level signal. When the circuit is detected to be completely full, the control system automatically closes the sealing valve 5, cuts off the negative pressure passage, and supplies three-phase AC power to the electromagnetic pump coil 6 to start the electromagnetic pump to work normally.

[0033] The electromagnetic pump can be an induction type or a conduction type, preferably an induction type. When the induction type electromagnetic pump is running, its operating frequency can be set to 30Hz to 100Hz, its magnetic field strength to 0.1T to 1.5T, and its diameter to Φ150mm to Φ300mm. In this embodiment, the preferred diameter is Φ200mm, and the circulation flow rate is controlled between 10L / min and 100L / min. A temperature control sensor monitors the temperature of the zinc liquid at the inlet of the electromagnetic pump or within the liquid metal circuit in real time. When the zinc liquid temperature deviates from the target range of 445℃ to 470℃, the control unit adjusts the excitation frequency or current of the electromagnetic pump to reduce thermal disturbance caused by excessive circulation.

[0034] This embodiment ensures that the electromagnetic pump starts with full liquid by pre-filling with negative pressure, avoiding the electromagnetic pump from running under no-load; reduces mechanical wear by electromagnetic drive; and protects the coil 6 by the heat-insulating shell 9, thereby achieving continuous and reliable extraction of zinc ash from the furnace nose.

[0035] Example 2 Based on Example 1, this embodiment further provides an operation control method suitable for a hot-dip galvanizing production line for high surface quality automotive outer panels, thereby enhancing the feasibility of the invention under different production rhythms.

[0036] In this embodiment, the suction port of the liquid metal circuit is located in the furnace nose near the strip inlet side and in the liquid surface area where zinc ash easily accumulates, while the return port is located in the zinc pot area away from the strip inlet side, so that the suction direction matches the natural return direction of the zinc liquid, avoiding the formation of severe local eddies near the strip surface.

[0037] In continuous production, the control unit controls the electromagnetic pump in three stages: low-flow start-up, medium-flow stable extraction, and short-term high-flow enhanced cleaning. During the low-flow start-up stage, the electromagnetic pump operates at a lower excitation frequency, causing the zinc liquid flow rate in the liquid metal circuit to rise steadily. During the medium-flow stable extraction stage, the electromagnetic pump maintains a stable flow rate, allowing the zinc liquid containing zinc ash to continuously enter the zinc inlet pipe 1 from the furnace nose. When the liquid level detection device and temperature control sensor feedback are both within the normal range, and the production line surface quality monitoring indicates an increased risk of inclusions, the control unit enters the short-term high-flow enhanced cleaning stage, increasing the excitation frequency or current and maintaining this for a predetermined time to accelerate the extraction of zinc ash from the furnace nose.

[0038] In this embodiment, the zinc bath temperature is preferably controlled between 450°C and 465°C, the electromagnetic pump circulation flow rate is preferably controlled between 20L / min and 80L / min, and the duration of the enhanced cleaning stage is preferably between 1min and 5min. Through the above-mentioned staged control, the zinc ash removal efficiency can be improved while ensuring a stable liquid level in the furnace nose, making it particularly suitable for high-grade hot-dip galvanized products sensitive to surface inclusions.

[0039] Compared with Example 1, this example further defines the arrangement of the suction port and the return port, so that the present invention can not only solve the problem of electromagnetic pump start-up reliability, but also dynamically adjust the zinc ash removal intensity according to the quality fluctuation of the production line, thereby enhancing the adaptability of the zinc ash extraction method in continuous industrial production.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A zinc ash extraction device for the zinc boiler nose of a hot-dip galvanizing unit, characterized in that, include: Electromagnetic pump; A liquid metal circuit is installed inside the electromagnetic pump. One end of the liquid metal circuit is provided with a zinc liquid inlet pipe (1), and the other end is provided with a zinc liquid outlet pipe (2). A filling valve (3) is installed on the zinc liquid outlet pipe (2). A vacuum line is installed on the zinc liquid outlet line (2) between the filling pump valve (3) and the electromagnetic pump, and a sealing valve (5) is installed on the vacuum line.

2. The zinc ash extraction device inside the zinc boiler nose of a hot-dip galvanizing unit according to claim 1, characterized in that, The electromagnetic pump is an induction electromagnetic pump or a conduction electromagnetic pump; when the electromagnetic pump is an induction electromagnetic pump, its operating frequency is 30Hz to 100Hz and its magnetic field strength is 0.1T to 1.5T. The electromagnetic pump is positioned above the liquid surface of the zinc pot, and there is a vertical height difference between the electromagnetic pump and the liquid surface of the zinc pot; the rated head of the electromagnetic pump is 0.5m to 5m, and the rated head is greater than the vertical height difference.

3. The zinc ash extraction device inside the zinc boiler nose of a hot-dip galvanizing unit according to claim 1, characterized in that, The electromagnetic pump includes an inner iron core (8), a coil (6), an outer iron core (7), and a heat-insulating shell (9) arranged from the inside out.

4. The zinc ash extraction device inside the zinc boiler nose of a hot-dip galvanizing unit according to claim 3, characterized in that, The liquid metal circuit is formed by a metal pipe sleeved on the inner iron core (8) and the inner iron core (8); The outer diameter of the metal pipe is 150mm to 300mm, and the wall thickness is 5mm to 12mm.

5. The zinc ash extraction device inside the zinc boiler nose of a hot-dip galvanizing unit according to claim 3, characterized in that, The heat insulation shell (9) includes an inner layer and an outer layer arranged from the inside out. The inner layer and the outer layer are evacuated to form a vacuum insulation layer, or are filled with a high-temperature resistant heat insulation medium.

6. The zinc ash extraction device inside the zinc boiler nose of a hot-dip galvanizing unit according to claim 5, characterized in that, The outer interlayer is equipped with nozzles, which are used to evacuate the inner and outer interlayers to form a vacuum insulation layer.

7. A zinc ash extraction device for the zinc boiler nose of a hot-dip galvanizing unit according to claim 1, characterized in that, The liquid metal circuit is also equipped with a liquid level detection device and a temperature control sensor.

8. A method for extracting zinc ash from the nose of a zinc boiler in a hot-dip galvanizing unit, characterized in that, It employs the apparatus as described in any one of claims 1-7, and includes the following steps: S1. Open the vacuum bottle in the vacuum device (4) and put the filling pump valve (3) and the sealing valve (5) into a vacuum connection state to evacuate the liquid metal circuit, so that the zinc liquid in the zinc pot enters the liquid metal circuit through the zinc liquid inlet pipe (1). S2. Determine whether the liquid metal circuit has reached the preset full state through the liquid level detection device; S3. When the liquid metal circuit reaches the preset full state, close or switch the negative pressure passage and start the electromagnetic pump. S4. Drive the zinc liquid to circulate in the liquid metal circuit by electromagnetic pump, extract the zinc liquid containing zinc ash in the furnace nose area and return it to the zinc pot through the zinc liquid outlet pipeline (2).

9. A zinc ash extraction device for the zinc boiler nose of a hot-dip galvanizing unit according to claim 8, characterized in that, The suction port of the liquid metal circuit is located in the liquid surface area inside the furnace nose, near the strip inlet side, where zinc ash tends to accumulate, while the return port is located in the zinc pot area, away from the strip inlet side.

10. A zinc ash extraction device for the zinc boiler nose of a hot-dip galvanizing unit according to claim 8, characterized in that, In step S4, the excitation frequency or current of the electromagnetic pump is adjusted according to the temperature signal detected by the temperature control sensor to maintain the zinc liquid temperature at 445°C to 470°C.

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