A surface treatment process for hot-dip galvanized zinc pot rollers

Abstract

This invention discloses a surface treatment process for hot-dip galvanized zinc pot rollers, relating to the field of zinc pot roller surface pretreatment, including the following steps: Step 1, zinc stripping; Step 2, old coating removal; Step 3, sandblasting; Step 4, nitrogen purging; Step 5, acetone cleaning. After the top of the acetone cleaning tank is opened, a lifting device hoists the roller body four onto the roller body support device inside the acetone cleaning tank. The roller body support device supports the roller body four and simultaneously drives the roller body four to rotate. A movable acetone cleaning device inside the acetone cleaning tank moves along the axial direction of the roller body four. During the movement of the movable acetone cleaning device, acetone vapor is sprayed onto the surface of the roller body four from above and recovered from below. The acetone vapor removes contaminants from the surface of the roller body four to obtain a pretreated roller body. The zinc pot roller surface treatment process of this invention can thoroughly remove impurities from the roller body surface before the roller body is recoated.

Description

Technical Field

[0001] This invention mainly relates to the technical field of surface pretreatment of zinc pot rollers, specifically a surface treatment process for hot-dip galvanized zinc pot rollers. Background Technology

[0002] Hot-dip galvanizing is a crucial process for corrosion protection of steel materials. Submerged rolls and stabilizing rolls, among other zinc pot roll components, are key equipment for ensuring the quality of the coating on the strip steel surface. These rolls operate for extended periods in a high-temperature, highly corrosive zinc bath environment, resulting in the formation of a zinc-iron alloy layer on their surfaces. They may also be coated with special ceramic or other protective coatings as required by the process. After a certain service life, the roll surfaces may exhibit wear, corrosion, or coating failure, necessitating repair and recoating to restore their performance. Therefore, efficient and thorough surface pretreatment of old rolls is a core prerequisite for ensuring remanufacturing quality and extending their service life.

[0003] Currently, surface pretreatment for such rollers typically includes high-temperature zinc stripping, machining to remove old coatings, sandblasting for roughening, and cleaning. However, in the final precision cleaning stage, existing technologies mostly employ manual wiping with organic solvents or alkaline cleaning solutions. These methods have significant limitations: manual wiping is inefficient and makes it difficult to ensure uniform cleanliness on large roller surfaces, easily leaving oil stains or fingerprints; while water-based cleaning agents may introduce moisture, which, if not thoroughly dried subsequently, can easily lead to zinc explosion risks in the high-temperature galvanizing environment, seriously threatening production safety. In addition, conventional steam cleaning technology often suffers from low solvent utilization and unsatisfactory cleaning results due to insufficient precision in temperature and fluid control, or may result in solvent residue and environmental pollution.

[0004] Therefore, there is an urgent need in the field for a pretreatment process that can thoroughly remove impurities from the surface of the roller before recoating it. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a surface treatment process for hot-dip galvanized zinc pan rollers to solve the technical problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a surface treatment process for hot-dip galvanized zinc pan rollers, comprising the following steps: Step 1, zinc stripping treatment: the roller body is placed in a sealed electrically heated zinc stripping furnace, the roller body temperature is raised to 550 degrees Celsius and held for two hours to melt and drip the zinc layer on the roller body surface, thus obtaining roller body one. During zinc stripping, positive pressure nitrogen is maintained in the furnace to prevent the roller body from oxidizing; Step 2, old coating removal: roller body one is machined using a CNC lathe, with a machining thickness of 0.4-0.6 mm, resulting in roller body two; Step 3, sandblasting treatment: roller body two is sandblasted using an automatic sandblasting machine, with sandblasting parameters of: pressure 0.45 MPa, gun distance 150 mm, coverage 150%, and surface Ra 4-8µm, after sandblasting, roller body three is obtained; Step four, nitrogen purging, the surface of roller body three is purged with nitrogen air knife, the gas pressure at the nitrogen knife nozzle is 0.2Mpa, after purging, roller body four is obtained; Step five, acetone cleaning, after the top of the acetone cleaning tank is opened, the lifting device lifts roller body four onto the roller support device inside the acetone cleaning tank. The roller support device supports roller body four and drives roller body four to rotate; the mobile acetone cleaning device inside the acetone cleaning tank moves along the axis of roller body four. During the movement of the mobile acetone cleaning device, acetone vapor is sprayed from above the roller body four onto the surface of roller body four, and acetone vapor is recovered from below the roller body four. The acetone vapor removes contaminants from the surface of roller body four to obtain the pre-treated roller body.

[0007] Preferably, in step five, the acetone vapor outlet temperature of the mobile acetone cleaning device is 55-60°C, and the acetone vapor recovery port of the mobile acetone cleaning device is maintained at -5 kPa and the inner wall temperature is 10°C. In this preferred embodiment, the acetone vapor outlet temperature of the mobile acetone cleaning device is 55-60°C, which is only 2-4°C higher than the boiling point of acetone. The superheat is small, and the vapor remains in the gas phase when it reaches the roller surface. All the latent heat is used to dissolve impurities, and no heat is wasted.

[0008] The mobile acetone cleaning device maintains an acetone vapor recovery port at -5kPa and an inner wall temperature of 10°C. The negative pressure of -5kPa can effectively draw away the vapor without damaging the vapor curtain, preventing unreacted vapor from being drawn away prematurely. The 10°C inner wall temperature causes most of the acetone vapor to condense into a liquid film within 0.1s, which is then forcibly drawn away along with the dissolved oil. By first condensing into liquid and then drawing it away, the volume is reduced by several times in an instant.

[0009] Preferably, the device includes an acetone cleaning tank, a roller support device located at the bottom of the inner wall of the acetone cleaning tank, and a mobile acetone cleaning device. The top of the acetone cleaning tank is equipped with an automatic opening and closing component. The mobile acetone cleaning device includes a positioning component located at the bottom of the inner wall of the acetone cleaning tank, and an upper arc-shaped outer cover and a lower arc-shaped outer cover symmetrically arranged at the actuating end of the positioning component. It also includes an acetone vapor guide hood located within the upper arc-shaped outer cover, a first temperature control component located within the acetone vapor guide hood, and an annular cooling component protruding from the bottom of the acetone vapor guide hood on its outer wall. Furthermore, it includes an acetone vapor recovery hood located within the lower arc-shaped outer cover, and a second temperature control component located within the acetone vapor recovery hood. In this preferred embodiment, the acetone cleaning tank achieves acetone vapor cleaning of the roller surface.

[0010] Preferably, the first temperature control component includes a temperature sensor disposed on the outer wall of the acetone vapor guide shroud with its sensing end extending into the acetone vapor guide shroud, a resistance heater disposed within the acetone vapor guide shroud, and a corrosion-resistant and heat-conducting layer covering the outside of the resistance heater. In this preferred embodiment, the first temperature control component facilitates precise control of the acetone vapor temperature.

[0011] Preferably, the annular cooling component includes an annular guide box fitted outside the acetone vapor guide shroud, an input pipe and an output pipe connected at one end to the annular guide box and extending at the other end to the outside of the upper arc-shaped outer cover, a heat-conducting ring disposed at the bottom of the annular guide box and protruding from the acetone vapor guide shroud, and a plurality of heat-conducting rods connected at one end to the heat-conducting ring and extending at the other end into the annular guide box. In this preferred embodiment, the annular cooling component facilitates localized weight gain and sinking of the steam, thereby facilitating the steam's action on the outer wall of the roller.

[0012] Preferably, the acetone vapor recovery hood includes a funnel-shaped cover located at the bottom of the inner wall of the lower arc-shaped outer cover, and two recovery holes symmetrically disposed at the bottom of the side wall of the funnel-shaped cover. In this preferred embodiment, the acetone vapor recovery hood facilitates the full recovery of acetone vapor or liquid.

[0013] Preferably, the second temperature control component includes two positioning boxes symmetrically arranged on both sides of the funnel cover, a semiconductor cooling chip disposed within the positioning box, a heat-conducting frame disposed on the inner wall of the funnel cover with its outer wall abutting against the semiconductor cooling chip, a plurality of heat-conducting cones disposed on the heat-conducting frame, and a plurality of heat-conducting ribs arranged in a ring array on the outer wall of the heat-conducting cones. In this preferred embodiment, the second temperature control component facilitates the condensation of acetone vapor into droplets.

[0014] Preferably, the positioning component includes two first support frames symmetrically arranged at the bottom of the inner wall of the acetone cleaning tank, two first linear modules connected to the top of the two first support frames at their respective ends, a second linear module disposed at the execution end of the first linear module and arranged in a cross shape with the first linear module, and a first bidirectional linear module vertically disposed at the execution end of the second linear module; the execution end of the first bidirectional linear module is connected to an upper arc-shaped outer cover and a lower arc-shaped outer cover. In this preferred embodiment, the positioning component enables the positioning and movement of the upper arc-shaped outer cover and the lower arc-shaped outer cover.

[0015] Preferably, the roller support device includes a second bidirectional linear module disposed at the bottom of the inner wall of the acetone cleaning tank, two second support frames disposed at the execution end of the second bidirectional linear module, a V-groove limiting frame disposed at the top of the second support frame, two support wheels symmetrically disposed within the V-groove limiting frame, and a drive motor disposed on the second support frame for driving one of the support wheels to rotate. In this preferred embodiment, the roller support device achieves both roller support and rotation drive.

[0016] Preferably, the automatic opening and closing component includes two opening and closing plates symmetrically arranged on the top of the acetone cleaning tank, and hydraulic cylinders symmetrically arranged on the side walls at both ends of the acetone cleaning tank for driving the opening and closing plates to move. In this preferred embodiment, the opening or closing of the top of the acetone cleaning tank is achieved by the automatic opening and closing component.

[0017] In summary, the present invention has the following main beneficial effects:

[0018] The zinc pot roller surface treatment process in this invention can completely remove impurities from the roller surface before the roller body is recoated.

[0019] The zinc stripping process effectively removes the old zinc layer and prevents substrate oxidation. Precision turning on a CNC lathe then completely removes the old coating. Sandblasting imparts a uniform and controllable surface roughness. Subsequent nitrogen purging ensures a clean, residue-free surface.

[0020] The core of the process lies in its mobile acetone steam cleaning system. This system maintains the steam outlet temperature at 55-60℃ through precise temperature control, just slightly above the boiling point of acetone. This ensures that the steam remains in the gas phase upon reaching the roller surface, allowing its latent heat to be fully utilized to dissolve impurities, thus achieving highly efficient cleaning with immediate drying. At the recovery end, the system maintains a negative pressure of -5kPa and a low inner wall temperature of 10℃, enabling rapid condensation and efficient steam recovery. This avoids damage to the steam curtain and significantly reduces the steam volume, lowering the recovery load. The design of the annular cooling components guides the steam downwards, forming a stable steam curtain, ensuring uniform and thorough cleaning. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention;

[0022] Figure 2 This is an isometric view of the acetone cleaning tank structure of the present invention;

[0023] Figure 3 This is an exploded view of the acetone cleaning tank structure of the present invention;

[0024] Figure 4 This is an isometric view of the mobile acetone cleaning device of the present invention.

[0025] Figure 5 This is an isometric view of the roller support device structure of the present invention;

[0026] Figure 6 This is an exploded view of the mobile acetone cleaning device of the present invention.

[0027] Figure 7 This is an exploded view of the mobile acetone cleaning device of the present invention.

[0028] Figure 8 This is a cross-sectional view of the roller support device structure of the present invention;

[0029] Figure 9 This is a cross-sectional view of the mobile acetone cleaning device of the present invention.

[0030] Figure 10 In this invention Figure 7 Enlarged view of the structure at point A in the image;

[0031] Figure 11 In this invention Figure 9 Enlarged view of the structure at point B in the image.

[0032] Figure Descriptions: 10. Acetone cleaning tank; 11. Automatic opening and closing component; 111. Opening and closing plate; 112. Hydraulic cylinder; 20. Roller support device; 21. Second bidirectional linear module; 22. Second support frame; 23. V-groove limiting frame; 24. Support wheel; 25. Drive motor; 30. Mobile acetone cleaning device; 31. Positioning component; 311. First support frame; 312. First linear module; 313. Second linear module; 314. First bidirectional linear module; 32. Upper arc-shaped outer cover; 33. Lower arc-shaped outer cover; 34. 35. Acetone vapor guide hood; 35. First temperature control component; 351. Temperature sensor; 352. Resistance heater; 353. Corrosion-resistant heat-conducting layer; 36. Annular cooling component; 361. Annular guide box; 362. Input pipe; 363. Output pipe; 364. Heat-conducting ring; 365. Heat-conducting rod; 37. Acetone vapor recovery hood; 371. Funnel hood; 372. Recovery hole; 38. Second temperature control component; 381. Positioning box; 382. Semiconductor cooling chip; 383. Heat-conducting frame; 384. Heat-conducting cone; 385. Heat-conducting rib. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0034] The embodiments of the present invention will now be described.

[0035] Please refer to the appendix for details. Figure 1-3As shown, in a preferred embodiment of the present invention, a surface treatment process for a hot-dip galvanized zinc pan roller includes the following steps: Step 1, zinc stripping treatment: The roller body is placed in a sealed electrically heated zinc stripping furnace, the roller body temperature is raised to 550 degrees Celsius and held for two hours to melt and drip the zinc layer on the roller body surface to obtain roller body one. During zinc stripping, positive pressure nitrogen is maintained in the furnace to prevent the roller body from oxidizing; Step 2, old coating removal: Roller body one is machined using a CNC lathe to a thickness of 0.4-0.6 mm to obtain roller body two; Step 3, sandblasting treatment: Roller body two is sandblasted using an automatic sandblasting machine with the following sandblasting parameters: pressure 0.45 MPa, gun distance 150 mm, coverage 150%, surface Ra 4-8 µm to obtain roller body three; Step 4, nitrogen purging: The surface of roller body three is purged using a nitrogen air knife. The gas pressure at the nitrogen knife nozzle is 0.2 MPa. After purging, roller body four is obtained. Step five: acetone cleaning. After the top of the acetone cleaning tank 10 is opened, the lifting device hoists the roller body four onto the roller support device 20 inside the acetone cleaning tank 10. The roller support device 20 supports the roller body four and drives the roller body four to rotate. The mobile acetone cleaning device 30 inside the acetone cleaning tank 10 moves along the axial direction of the roller body four. During the movement of the mobile acetone cleaning device 30, acetone vapor is sprayed from above the roller body four onto the surface of the roller body four, and acetone vapor is recovered from below the roller body four. The acetone vapor removes contaminants from the surface of the roller body four to obtain a pre-treated roller body. In step five, the outlet temperature of the acetone vapor nozzle of the mobile acetone cleaning device 30 is 55-60℃, and the acetone vapor recovery port of the mobile acetone cleaning device 30 is maintained at -5 kPa and the inner wall temperature is 10℃.

[0036] It should be noted that in this embodiment, for the zinc stripping process, the zinc pot roller to be repaired is hoisted into a well-type closed electric heating zinc stripping furnace. The heating rate is controlled at 8°C per minute, and the temperature is raised from room temperature to 550°C and held for 2 hours. During the holding period, 99.9% nitrogen gas is introduced into the furnace at a flow rate of 15 m³ / h, maintaining a positive pressure of 200-300 Pa. After the holding period, the roller is cooled to ≤200°C with the furnace, and the roller body is then removed from the furnace. Visual inspection: The original silver-gray zinc layer on the surface is completely melted and dripped off, with no blue-black high-temperature oxide spots, which is considered acceptable.

[0037] After removing the old coating, the first roller body is clamped onto a CNC lathe. The spindle speed of the CNC lathe is 80 r / min, and the tool post traverse speed is 0.25 mm / r. The turning is completed in 3 cuts, with a total cutting thickness of 0.4-0.6 mm, to obtain the second roller body.

[0038] Sandblasting treatment: Roller body two is fed into a four-gun automatic through-type sandblasting machine. Process parameters: compressed air pressure 0.45MPa, spray gun distance from roller surface 150mm, roller rotation speed 3r / min, carriage lateral movement 80mm / min, to achieve 150% coverage. The surface roughness after sandblasting is Ra4-8µm, to obtain roller body three.

[0039] Nitrogen purging is performed by slit-type nitrogen air knives arranged above the outlet station of the same sandblasting machine. The nitrogen source is an on-site nitrogen generator, which reduces the pressure to 0.2MPa after passing through a 0.01µm precision filter, with a flow rate of 90Nm³ / h. The air knife is at a 15° angle to the tangent of the roller surface and a distance of 10mm. The roller body rotates at 2r / min, and the trolley moves synchronously to obtain four roller bodies.

[0040] After the automatic opening and closing component 11 at the top of the acetone cleaning tank 10 is opened, the lifting device hoists the roller body four onto the roller support device 20 inside the acetone cleaning tank 10. The roller support device 20 supports the roller body four and drives the roller body four to rotate. The mobile acetone cleaning device 30 moves along the axial direction of the roller body four and supplies acetone steam through the acetone steam guide hood 34 connected to the acetone steam supply system via a pipeline. The acetone steam cleans the surface of the roller body. At this time, the acetone recovery system connected to the acetone steam recovery hood 37 starts to work. The acetone steam or acetone liquid after the roller body is cleaned is recovered by the acetone recovery system through the acetone steam recovery hood 37.

[0041] Furthermore, as a strong organic solvent, acetone can instantly dissolve impurities with similar properties on the roller surface. The liquid droplets containing dissolved impurities drip off under gravity. At the same time, due to the high volatility of acetone, when the surface temperature of the roller rises to near the boiling point of acetone in a steam environment, the trace amount of acetone remaining on the surface will quickly and completely evaporate into gas, leaving no residue or stains, thus achieving instant washing and drying.

[0042] Furthermore, the mobile acetone cleaning device has an acetone vapor nozzle outlet temperature of 55-60℃, which is only 2-4℃ higher than the boiling point of acetone. The superheat is small, and the vapor phase is maintained when it reaches the roller surface. All the latent heat is used to dissolve impurities, without wasting heat.

[0043] The mobile acetone cleaning device maintains a acetone vapor recovery port of -5kPa and an inner wall temperature of 10°C. The negative pressure of -5kPa can draw away the vapor without damaging the vapor curtain, and will not draw away unreacted vapor in advance. The inner wall temperature of 10°C causes most of the acetone vapor to condense into a liquid film within 0.1s, which is then forcibly drawn away along with the dissolved oil. The vapor is first condensed into liquid and then drawn away, instantly reducing the volume by several times.

[0044] Furthermore, the acetone vapor supply system includes a solvent storage tank, a solvent pump, an evaporator, a saturated vapor pressure stabilizing tank, and a heated steam pipeline. The heated steam pipeline is connected to the acetone vapor guide hood 34. Liquid acetone is stored in the solvent storage tank and precisely pumped into the evaporator by the solvent pump. The evaporator is heated to 58°C and maintained at a constant temperature to completely vaporize the liquid acetone into saturated acetone vapor. The saturated acetone vapor then enters the saturated vapor pressure stabilizing tank to stabilize its pressure and flow rate. Finally, the vapor is transported via the heated steam pipeline.

[0045] The acetone recovery system includes an explosion-proof variable frequency fan, a heat exchanger, and a liquid-gas separator. The input end of the explosion-proof variable frequency fan is connected to the funnel hood 371 through a pipe. Acetone vapor containing contaminants and unreacted substances is drawn into the recovery pipe and first passes through the heat exchanger, which cools the mixed gas to below 10°C, causing most of the acetone vapor to condense into droplets. Subsequently, the gas-liquid mixture enters the liquid-gas separator, where liquid acetone and dissolved oil are separated and collected. This can be purified and reused in the solvent storage tank, while the separated non-condensable gas is discharged through a safety outlet. The explosion-proof variable frequency fan is preferably installed after the liquid-gas separator to handle dry gas and ensure safe operation.

[0046] When acetone vapor is supplied and recovered, the acetone vapor supply system first preheats the evaporator to 58°C and stabilizes it for 3 minutes. The explosion-proof variable frequency fan is then used to generate negative pressure, and the valve of the saturated steam pressure stabilizing tank is opened to supply acetone vapor.

[0047] Please refer to the appendix for details. Figure 3 , 5 As shown in Figure 8, in another preferred embodiment of the present invention, the device includes an acetone cleaning tank 10, a roller support device 20 disposed at the bottom of the inner wall of the acetone cleaning tank 10, and a movable acetone cleaning device 30. The top of the acetone cleaning tank 10 is provided with an automatic opening and closing component 11. The roller support device 20 includes a second bidirectional linear module 21 disposed at the bottom of the inner wall of the acetone cleaning tank 10, two second support frames 22 disposed at the execution end of the second bidirectional linear module 21, a V-groove limiting frame 23 disposed at the top of the second support frame 22, two support wheels 24 symmetrically disposed in the V-groove limiting frame 23, and a drive motor 25 disposed on the second support frame 22 for driving one of the support wheels 24 to rotate. The automatic opening and closing component 11 includes two opening and closing plates 111 symmetrically disposed at the top of the acetone cleaning tank 10, and hydraulic cylinders 112 symmetrically disposed at both ends of the acetone cleaning tank 10 for driving the opening and closing plates 111 to move.

[0048] It should be noted that, in this embodiment, when the automatic opening and closing component 11 is working, the actuator of the hydraulic cylinder 112 drives the opening and closing plate 111 to move.

[0049] Furthermore, when the roller support device 20 is working, the execution end of the second bidirectional linear module 21 drives the two second support frames 22 to move, so as to adjust the distance between the two second support frames 22 to the set value. The lifting device lifts the roller body to the roller body end located in the V groove limit frame 23 and abuts against the support wheel 24. The execution end of the drive motor 25 amplifies the torque through the reducer and drives the support wheel 24 to rotate. The support wheel 24 can drive the roller body to rotate.

[0050] Please refer to the appendix for details. Figure 4 , 6As shown in Figures 7, 9, 10, and 11, in another preferred embodiment of the present invention, the mobile acetone cleaning device 30 includes a positioning component 31 disposed at the bottom of the inner wall of the acetone cleaning tank 10, and an upper arc-shaped outer cover 32 and a lower arc-shaped outer cover 33 symmetrically disposed at the execution end of the positioning component 31; it also includes an acetone vapor guide hood 34 disposed within the upper arc-shaped outer cover 32, a first temperature control component 35 disposed within the acetone vapor guide hood 34, and an annular cooling component 36 on the outer wall of the acetone vapor guide hood 34 with its bottom protruding from the acetone vapor guide hood 34; it also includes an acetone vapor recovery hood 37 disposed within the lower arc-shaped outer cover 33, and an acetone vapor recovery hood 38 disposed within the lower arc-shaped outer cover 33. The second temperature control component 38 within the 7th layer, the first temperature control component 35 includes a temperature sensor 351 disposed on the outer wall of the acetone vapor guide hood 34 with its detection end extending into the acetone vapor guide hood 34, a resistance heater 352 disposed within the acetone vapor guide hood 34, and a corrosion-resistant heat-conducting layer 353 covering the outside of the resistance heater 352, the annular cooling component 36 includes an annular guide box 361 sleeved on the outside of the acetone vapor guide hood 34, an input pipe 362 connected at one end to the annular guide box 361 and an output pipe 363 extending at the other end to the outside of the upper arc-shaped outer cover 32, and a component disposed at the bottom of the annular guide box 361 and protruding from the acetone vapor guide hood 34. The vapor guide shroud 34 includes a heat-conducting ring 364 and multiple heat-conducting rods 365, one end of which is connected to the heat-conducting ring 364 and the other end of which extends into the annular guide box 361. The acetone vapor recovery shroud 37 includes a funnel shroud 371 located at the bottom of the inner wall of the lower arc-shaped outer shroud 33, and two recovery holes 372 symmetrically arranged at the bottom of the side wall of the funnel shroud 371. The second temperature control component 38 includes two positioning boxes 381 symmetrically arranged on both sides of the funnel shroud 371, a semiconductor cooling chip 382 located in the positioning box 381, a heat-conducting frame 383 located on the inner wall of the funnel shroud 371 with its outer wall abutting against the semiconductor cooling chip 382, ​​and a heat-conducting frame 383 located on the heat-conducting frame. The positioning component 31 includes two first support frames 311 symmetrically arranged at the bottom of the inner wall of the acetone cleaning tank 10, two first linear modules 312 respectively connected to the top of the two first support frames 311 at both ends, a second linear module 313 arranged at the execution end of the first linear module 312 and divided in a cross shape with the first linear module 312, and a first bidirectional linear module 314 vertically arranged at the execution end of the second linear module 313; the execution end of the first bidirectional linear module 314 is connected to the upper arc-shaped outer cover 32 and the lower arc-shaped outer cover 33.

[0051] It should be noted that, in this embodiment, when the mobile acetone cleaning device 30 is working, the positioning component 31 drives the upper arc-shaped outer cover 32 and the lower arc-shaped outer cover 33 to hug the outer wall of the roller body and move along the roller body axis at a set speed. The first temperature control component 35 adjusts the temperature of the acetone vapor. When the acetone vapor sprayed through the acetone vapor guide hood 34 passes through the ring cooling component 36, the vapor locally increases in weight and sinks, so that the vapor can act on the outer wall of the roller body. The cleaned acetone vapor is recovered through the acetone vapor recovery hood 37. The second temperature control component 38 can condense the acetone vapor into liquid.

[0052] Furthermore, when the first temperature control component 35 is working, the controller receives the acetone vapor temperature information measured by the temperature sensor 351 and adjusts the power of the resistance heater 352 after analysis. The heat is radiated to the acetone vapor through the anti-corrosion heat-conducting layer 353.

[0053] Furthermore, when the annular cooling component 36 is working, a horizontal plate can be installed at the execution end of the second linear module 313, and a cooling liquid circulation supply system can be installed on the horizontal plate. The cooling liquid circulation supply system supplies cooling liquid into the input pipe 362. The cooling liquid returns to the cooling liquid circulation supply system through the input pipe 362, the annular guide box 361 and the output pipe 363. The cooling liquid performs thermal radiation cooling on the heat-conducting rod 365 and the heat-conducting ring 364.

[0054] The cooling liquid circulation supply system includes a mixing tank, a circulation pump, a cooling module and a temperature monitoring module installed in the mixing tank. The controller receives the cooling liquid temperature information measured by the temperature monitoring module and triggers the cooling module until the cooling liquid in the mixing tank reaches the set value. The circulation pump pumps the cooling liquid in the mixing tank into the input pipe 362, and the cooling liquid returns to the mixing tank through the output pipe 363.

[0055] Furthermore, when the acetone vapor recovery hood 37 recovers vapor, the acetone vapor or droplets can be recovered through the second temperature control component 38 or the recovery hole 372.

[0056] Furthermore, when the second temperature control component 38 is working, the semiconductor cooling chip 382 is energized and cooled down. The heat from the semiconductor cooling chip 382 is conducted to the heat-conducting frame 383, the heat-conducting cone 384, and the heat-conducting rib 385, which facilitate the condensation of acetone vapor into liquid.

[0057] The working principle of this invention is as follows:

[0058] For zinc stripping, the zinc pot roller to be repaired is hoisted into a well-type closed electric heating zinc stripping furnace. The heating rate is controlled at 8℃ per minute, rising from room temperature to 550℃ and then held for 2 hours. During the holding period, 99.9% nitrogen gas is introduced into the furnace at a flow rate of 15 m³ / h, maintaining a positive pressure of 200-300 Pa. After the holding period, the roller is cooled to ≤200℃ with the furnace. The roller body is then removed from the furnace. Visual inspection: The original silver-gray zinc layer on the surface is completely melted and dripped off, with no blue-black high-temperature oxide spots, which is considered acceptable.

[0059] After removing the old coating, the first roller body is clamped onto a CNC lathe. The spindle speed of the CNC lathe is 80 r / min, and the tool post traverse speed is 0.25 mm / r. The turning is completed in 3 cuts, with a total cutting thickness of 0.4-0.6 mm, to obtain the second roller body.

[0060] Sandblasting treatment: Roller body two is fed into a four-gun automatic through-type sandblasting machine. Process parameters: compressed air pressure 0.45MPa, spray gun distance from roller surface 150mm, roller rotation speed 3r / min, carriage lateral movement 80mm / min, to achieve 150% coverage. The surface roughness after sandblasting is Ra4-8µm, to obtain roller body three.

[0061] Nitrogen purging is performed by slit-type nitrogen air knives arranged above the outlet station of the same sandblasting machine. The nitrogen source is an on-site nitrogen generator, which reduces the pressure to 0.2MPa after passing through a 0.01µm precision filter, with a flow rate of 90Nm³ / h. The air knife is at a 15° angle to the tangent of the roller surface and a distance of 10mm. The roller body rotates at 2r / min, and the trolley moves synchronously to obtain four roller bodies.

[0062] After the automatic opening and closing component 11 at the top of the acetone cleaning tank 10 is opened, the lifting device hoists the roller body four onto the roller support device 20 inside the acetone cleaning tank 10. The roller support device 20 supports the roller body four and drives the roller body four to rotate. The mobile acetone cleaning device 30 moves along the axial direction of the roller body four and supplies acetone steam through the acetone steam guide hood 34 connected to the acetone steam supply system via a pipeline. The acetone steam cleans the surface of the roller body. At this time, the acetone recovery system connected to the acetone steam recovery hood 37 starts to work. The acetone steam or acetone liquid after the roller body is cleaned is recovered by the acetone recovery system through the acetone steam recovery hood 37.

[0063] As a strong organic solvent, acetone can instantly dissolve impurities with similar properties on the roller surface. The dissolved impurity droplets fall off under gravity. At the same time, due to the high volatility of acetone, when the roller surface temperature rises to near the boiling point of acetone in a steam environment, the trace amount of acetone remaining on the surface will quickly and completely evaporate into gas, leaving no residue or stains, thus achieving instant washing and drying.

[0064] The mobile acetone cleaning device has an acetone vapor nozzle outlet temperature of 55-60℃, which is only 2-4℃ higher than the boiling point of acetone. The superheat is small, and the vapor phase is still maintained when it reaches the roller surface. All the latent heat is used to dissolve impurities, and no heat is wasted.

[0065] The mobile acetone cleaning device maintains a acetone vapor recovery port of -5kPa and an inner wall temperature of 10°C. The negative pressure of -5kPa can draw away the vapor without damaging the vapor curtain, and will not draw away unreacted vapor in advance. The inner wall temperature of 10°C causes most of the acetone vapor to condense into a liquid film within 0.1s, which is then forcibly drawn away along with the dissolved oil. The vapor is first condensed into liquid and then drawn away, instantly reducing the volume by several times.

[0066] The acetone vapor supply system includes a solvent storage tank, a solvent pump, an evaporator, a saturated vapor pressure stabilizing tank, and a heated steam pipeline, which is connected to the acetone vapor guide hood 34.

[0067] The acetone recovery system includes an explosion-proof variable frequency fan, a heat exchanger, and a liquid-gas separator. The input end of the explosion-proof variable frequency fan is connected to the funnel cover 371 through a pipe.

[0068] When acetone vapor is recovered, the acetone vapor supply system first preheats the evaporator to 58°C and stabilizes it for 3 minutes. The explosion-proof variable frequency fan is then pulled into negative pressure, and the valve of the saturated steam pressure stabilizing tank is opened to supply acetone vapor.

[0069] When the automatic opening and closing component 11 is working, the actuator of the hydraulic cylinder 112 drives the opening and closing plate 111 to move.

[0070] When the roller support device 20 is working, the execution end of the second bidirectional linear module 21 drives the two second support frames 22 to move, so as to adjust the distance between the two second support frames 22 to the set value. The lifting device lifts the roller body to the roller body end located in the V groove limit frame 23 and abuts against the support wheel 24. The execution end of the drive motor 25 drives the support wheel 24 to rotate after the torque is amplified by the reducer. The support wheel 24 can drive the roller body to rotate.

[0071] When the mobile acetone cleaning device 30 is working, the positioning component 31 drives the upper arc-shaped outer cover 32 and the lower arc-shaped outer cover 33 to hug the outer wall of the roller body and move along the roller body axis at a set speed. The first temperature control component 35 adjusts the temperature of the acetone vapor. When the acetone vapor sprayed through the acetone vapor guide hood 34 passes through the ring cooling component 36, the vapor locally increases in weight and sinks, so that the vapor can act on the outer wall of the roller body. The cleaned acetone vapor is recovered through the acetone vapor recovery hood 37. The second temperature control component 38 can condense the acetone vapor into liquid.

[0072] When the first temperature control component 35 is working, the controller receives the acetone vapor temperature information measured by the temperature sensor 351 and adjusts the power of the resistance heater 352 after analysis. The heat is radiated to the acetone vapor through the anti-corrosion heat-conducting layer 353.

[0073] When the annular cooling component 36 is working, a horizontal plate can be installed at the execution end of the second linear module 313. A cooling liquid circulation supply system can be installed on the horizontal plate. The cooling liquid circulation supply system supplies cooling liquid into the input pipe 362. The cooling liquid returns to the cooling liquid circulation supply system through the input pipe 362, the annular guide box 361 and the output pipe 363. The cooling liquid performs thermal radiation cooling on the heat-conducting rod 365 and the heat-conducting ring 364.

[0074] The cooling liquid circulation supply system includes a mixing tank, a circulation pump, a cooling module and a temperature monitoring module installed in the mixing tank. The controller receives the cooling liquid temperature information measured by the temperature monitoring module and triggers the cooling module until the cooling liquid in the mixing tank reaches the set value. The circulation pump pumps the cooling liquid in the mixing tank into the input pipe 362, and the cooling liquid returns to the mixing tank through the output pipe 363.

[0075] When the acetone vapor recovery hood 37 recovers vapor, the acetone vapor or droplets can be recovered through the second temperature control component 38 or the recovery hole 372;

[0076] When the second temperature control component 38 is working, the semiconductor cooling chip 382 is energized to cool down. The heat from the semiconductor cooling chip 382 is conducted to the heat-conducting frame 383, the heat-conducting cone 384, and the heat-conducting rib 385. The heat-conducting frame 383, the heat-conducting cone 384, and the heat-conducting rib 385 facilitate the condensation of acetone vapor into liquid.

[0077] Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions, and variations to the embodiments as needed without departing from the principles and spirit of the invention, but such modifications, substitutions, and variations are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A surface treatment process for hot-dip galvanizing zinc pan rollers, characterized in that, Includes the following steps: Step 1: Zinc stripping treatment. Place the roller in a sealed electric heating zinc stripping furnace. Raise the roller temperature to 550 degrees Celsius and keep it at that temperature for two hours to melt and drip the zinc layer on the roller surface to obtain roller 1. During zinc stripping, maintain positive pressure nitrogen in the furnace to prevent the roller from oxidizing. Step 2: Remove the old coating. Use a CNC lathe to machine roller body one to a thickness of 0.4-0.6mm. After machining, roller body two is obtained. Step 3: Sandblasting treatment. Use an automatic sandblasting machine to sandblast the roller body two. The sandblasting parameters are: pressure 0.45MPa, gun distance 150mm, coverage 150%, surface Ra4-8µm. After sandblasting, roller body three is obtained. Step 4: Nitrogen purging. Use a nitrogen air knife to purge the three surfaces of the roller body. The gas pressure at the nitrogen knife nozzle is 0.2 MPa. After purging, the roller body is obtained. Step 5: Acetone cleaning. After the top of the acetone cleaning tank (10) is opened, the hoist will lift the roller four onto the roller support device (20) inside the acetone cleaning tank (10). The roller support device (20) supports the roller four and drives the roller four to rotate. The mobile acetone cleaning device (30) inside the acetone cleaning tank (10) moves along the four axes of the roller body. During the movement of the mobile acetone cleaning device (30), acetone vapor is sprayed from above the four roller bodies onto the four roller bodies and acetone vapor is recovered from below the four roller bodies. The acetone vapor removes contaminants from the four roller bodies to obtain a pre-treated roller body. In step five, the acetone steam nozzle outlet temperature of the mobile acetone cleaning device (30) is 55-60℃, and the acetone steam recovery port of the mobile acetone cleaning device (30) is maintained at -5kPa and the inner wall temperature is 10℃. It also includes an acetone cleaning tank (10), a roller support device (20) located at the bottom of the inner wall of the acetone cleaning tank (10), and a mobile acetone cleaning device (30). The top of the acetone cleaning tank (10) is provided with an automatic opening and closing component (11). The mobile acetone cleaning device (30) includes a positioning component (31) located at the bottom of the inner wall of the acetone cleaning tank (10), and an upper arc-shaped outer cover (32) and a lower arc-shaped outer cover (33) symmetrically located at the execution end of the positioning component (31). It also includes an acetone vapor guide hood (34) disposed inside the upper arc-shaped outer cover (32), a first temperature control component (35) disposed inside the acetone vapor guide hood (34), and an annular cooling component (36) on the outer wall of the acetone vapor guide hood (34) and protruding from the bottom of the acetone vapor guide hood (34). It also includes an acetone vapor recovery hood (37) disposed within the lower arc-shaped outer cover (33), and a second temperature control component (38) disposed within the acetone vapor recovery hood (37). The annular cooling component (36) includes an annular flow guide box (361) sleeved outside the acetone vapor guide hood (34), an input pipe (362) connected to the annular flow guide box (361) at one end and an output pipe (363) extending to the outside of the upper arc-shaped outer cover (32) at the other end, a heat-conducting ring (364) disposed at the bottom of the annular flow guide box (361) and protruding from the acetone vapor guide hood (34), and a heat-conducting ring (364) connected at one end to the heat-conducting ring (364). 364) The other end extends into the annular guide box (361) and a plurality of heat-conducting rods (365). The roller support device (20) includes a second bidirectional linear module (21) located at the bottom of the inner wall of the acetone cleaning tank (10), two second support frames (22) located at the execution end of the second bidirectional linear module (21), a V-groove limiting frame (23) located at the top of the second support frame (22), two support wheels (24) symmetrically located in the V-groove limiting frame (23), and a drive motor (25) located on the second support frame (22) for driving one of the support wheels (24) to rotate.

2. The surface treatment process for hot-dip galvanizing zinc pan rollers according to claim 1, characterized in that, The first temperature control component (35) includes a temperature sensor (351) disposed on the outer wall of the acetone vapor guide hood (34) and whose detection end extends into the acetone vapor guide hood (34), a resistance heater (352) disposed in the acetone vapor guide hood (34), and a corrosion-resistant heat-conducting layer (353) covering the outside of the resistance heater (352).

3. The surface treatment process for hot-dip galvanizing zinc pan rollers according to claim 1, characterized in that, The acetone vapor recovery hood (37) includes a funnel hood (371) located at the bottom of the inner wall of the lower arc-shaped outer hood (33), and two recovery holes (372) symmetrically arranged at the bottom of the side wall of the funnel hood (371).

4. The surface treatment process for hot-dip galvanizing zinc pan rollers according to claim 3, characterized in that, The second temperature control component (38) includes two positioning boxes (381) symmetrically arranged on both sides of the funnel cover (371), a semiconductor cooling chip (382) disposed in the positioning box (381), a heat-conducting frame (383) disposed on the inner wall of the funnel cover (371) and whose outer wall abuts against the semiconductor cooling chip (382), a plurality of heat-conducting cones (384) disposed on the heat-conducting frame (383), and a plurality of heat-conducting ribs (385) arranged in a ring array on the outer wall of the heat-conducting cones (384).

5. The surface treatment process for hot-dip galvanizing zinc pot rollers according to claim 1, characterized in that, The positioning component (31) includes two first support frames (311) symmetrically arranged at the bottom of the inner wall of the acetone cleaning tank (10), a first linear module (312) connected to the top of the two first support frames (311) at both ends, a second linear module (313) arranged at the execution end of the first linear module (312) and divided in a cross shape with the first linear module (312), and a first bidirectional linear module (314) vertically arranged at the execution end of the second linear module (313). The first bidirectional linear module (314) is connected to the upper arc-shaped outer cover (32) and the lower arc-shaped outer cover (33) at its execution end.

6. The surface treatment process for hot-dip galvanizing zinc pan rollers according to claim 1, characterized in that, The automatic opening and closing component (11) includes two opening and closing plates (111) symmetrically arranged on the top of the acetone cleaning tank (10), and hydraulic cylinders (112) symmetrically arranged on the side walls at both ends of the acetone cleaning tank (10) for driving the opening and closing plates (111) to move.

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