A production method of a screen roll-coating PFA anticorrosion equipment

Abstract

The application discloses a production method of a screen roll-coating PFA anti-corrosion equipment, and comprises the following steps: S1, preparing a container body and PFA lining raw materials in advance; S2, laying a diamond steel screen on the inner surface of the container body in the step S1, and then performing sand blasting treatment again; S3, performing primer spraying on the inner surface of the container body in the step S2; S4, after the step S3, closing all the pipe openings of the container body on which the primer is sprayed, and leaving only one feeding opening; S5, after the step S4, transporting the container body in the step S3 into a roll molding furnace by using a tool, and then performing heating treatment and adding PFA lining powder for treatment; S6, naturally cooling the container body processed in the step S5; and S7, taking the container body in the step S6 out of the roll molding furnace to obtain a finished product. The application ends the existing technology by using the production process of the roll-coating PFA, and makes the container body have better corrosion resistance, so that the container body can be applied to the heavy anti-corrosion field environment.

Description

Technical Field

[0001] This invention relates to the field of atmospheric pressure vessel technology, and in particular to a method for manufacturing a PFA anti-corrosion equipment with a mesh coating. Background Technology

[0002] Atmospheric pressure vessels generally refer to equipment such as corrosion-resistant reactors, storage tanks, or towers. Since they are in direct contact with corrosive media, the core protection objective is to achieve media isolation through material selection or lining / coating to ensure structural integrity and operational safety. Therefore, they are core equipment in industrial production fields such as chemical, pharmaceutical, and food industries.

[0003] Atmospheric pressure vessels are exposed to corrosive environments such as acids, alkalis, solvents, and salt spray for extended periods. The protection of their internal surfaces directly impacts equipment lifespan and production safety. Proper painting not only provides an aesthetically pleasing appearance but, more importantly, forms an effective corrosion barrier. Based on long-term engineering practice, a high-quality atmospheric pressure vessel coating system should possess multiple protective functions, such as resistance to strong acids and alkalis (pH range typically covering 1-14), tolerance to organic solvent erosion, adaptability to extreme temperature fluctuations from -190°C to 200°C, and stability under high pressure or vacuum conditions. Currently, the internal surfaces of atmospheric pressure vessels generally rely on corrosion-resistant materials (such as 316L, Hastelloy, and titanium) or lining / coating protection (such as PTFE, PP, glass flakes, and rubber linings) to prevent corrosive media from contacting the pressure-bearing / load-bearing substrate (usually carbon steel). However, existing technologies involve adding coatings inside atmospheric pressure vessels through spraying processes. These coatings often employ fluoroplastics such as PFA. This technology requires precise control within a thickness range of 300-1000µm, and the spraying process must be carried out in multiple layers. The interval between each coating layer application must be strictly controlled by the ambient temperature and humidity, and 100% electric spark testing (test voltage is usually 3-7kV / mm) is required to ensure the absence of pinhole defects. However, atmospheric pressure vessels made using this type of spraying cannot be used in heavy-duty corrosion-resistant environments (high temperature resistance, high corrosion resistance, and high negative pressure resistance). Therefore, there is an urgent need for improvement. Summary of the Invention

[0004] (a) Technical problems that need to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a method for manufacturing PFA anti-corrosion equipment using a mesh-coated roller coating process. This method eliminates the need for simple spraying processes in existing technologies. The resulting anti-corrosion equipment exhibits resistance to negative pressure and high temperatures, along with enhanced corrosion resistance, making it more suitable for heavy-duty anti-corrosion applications and demonstrating strong practicality.

[0006] (ii) Technical solutions to be adopted

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for manufacturing a PFA anti-corrosion coating equipment with a screen and roller coating includes the following steps:

[0009] S1. Prepare the container body and PFA lining powder in advance;

[0010] S2. Lay a diamond-shaped steel mesh on the inner surface of the tank in step S1 above, and then perform sandblasting again.

[0011] S3. Apply a primer to the inner surface of the container in step S2 above.

[0012] S4. After step S3 above, seal all the openings of the container body that has been sprayed with primer, leaving only one feeding port.

[0013] S5. After step S4 above, use tools to transport the container body from step S3 above into the rotational molding furnace, and then fix the container body to the rotational molding furnace with fixtures.

[0014] S6. After step S5 above, close the door of the rotational molding furnace, and then control the heating temperature to the temperature at which the material can melt. When the temperature is reached, add PFA lining powder through the reserved feeding port for processing.

[0015] S7. Allow the container body processed in step S6 to cool naturally, so that the PFA raw material inside the container body has completely solidified and formed the inner lining layer.

[0016] S8. Remove the container from the rotational molding furnace in step S7 to obtain the finished product.

[0017] Preferably, the container body in step S1 needs to be sandblasted, and the prepared container body and PFA lining material need to be inspected according to relevant regulations, and their density should meet the standards.

[0018] Preferably, in step S2, a diamond-shaped steel mesh is first welded, and then the welded diamond-shaped steel mesh is laid to cover the entire inner surface of the tank. Next, it is welded using a CO2 gas shielded welding machine, and then sandblasted again after welding.

[0019] Preferably, in step S2, high-pressure compressed air generated by an air compressor is used as power to spray bearing steel sand from the spray gun at high speed onto the surface of the container for rust removal, sand removal, strengthening, or surface treatment.

[0020] Preferably, after step S2, the container body is sandblasted using an air compressor, and then the inner metal surface of the container body is subjected to manual mechanical high-pressure sandblasting.

[0021] Preferably, the air compressor is a six-cubic-meter air compressor.

[0022] Preferably, before applying the primer, the container body from step S2 above needs to be thoroughly cleaned, and then the primer is applied to the container body using a spray gun, ensuring that the primer covers the entire inner surface of the container.

[0023] Preferably, residual sand and dust in the container are cleaned using a high-powered vacuum cleaner.

[0024] Preferably, the raw material of the primer is TC-11000.

[0025] Preferably, in step S4 above, a fixing ring is made by rolling a sheet metal and placing it on the outer edge of the flange sealing surface of the container body. A cover plate is placed on the fixing ring, and the cover plate is locked to the fixing ring with screws. After completion, each bolt hole needs to be checked to ensure that all gaps are sealed. Only one feeding port is left in the container body, and all other pipe ports are sealed.

[0026] Preferably, in step S5 above, the lower clamp is installed first in the rotational molding furnace. After the container body is transported into the rotational molding furnace by tools, the container body is then clamped by the lower clamp and the upper clamp, and finally welded in place with welding rods.

[0027] Preferably, the melting temperature of the material in step S6 is 360°C to 370°C.

[0028] Preferably, in step S6 above, after the temperature is reached, PFA liner material is added through the reserved feeding port, and the container body in the rotational molding furnace is immediately subjected to three-dimensional rotational coating for 2 hours to form. The rotation in the rotational molding furnace allows the PFA material to reach every corner, achieving one-time molding.

[0029] Preferably, after step S8, the processed container body needs to be shaped and tested for integrity in sequence, and only after passing the test can it officially become a product.

[0030] (III) The technical effects to be achieved

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] Firstly, the present invention uses a production process of adding a screen and rolling PFA to end the existing technology of using a spraying process. The anti-corrosion equipment manufactured in this way has the properties of resistance to negative pressure, high temperature and corrosion, and can be used in heavy anti-corrosion environments, which has strong practicality.

[0033] Secondly, the production process of PFA by adding a screen and rolling it can greatly increase the coating thickness. Compared with the traditional spraying process, the anti-corrosion equipment has stronger corrosion resistance and can be more suitable for heavy-duty anti-corrosion environments, and can better meet the needs of modern users. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0035] In the description of this invention, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to or indirectly connected to the other element.

[0036] In the description of this invention, it should be noted that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0037] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0039] Example 1: See Figure 1A method for manufacturing a PFA anti-corrosion coating equipment with a screen and roller coating includes the following steps:

[0040] S1. Prepare the tank body and PFA lining powder in advance.

[0041] The tank body needs to be sandblasted to remove burrs, rust, and debris, and the outer surface should be roughened to increase the adhesion of the PFA lining powder. The PFA lining powder should be prepared according to the "Technical Specifications for Design of Lined Steel Shells," ensuring the steel parts are ground to remove sharp edges and corners, with rounded transitions at the branch pipe openings. Welds must be free of porosity, undercut, cracks, and any other surface holes or incomplete penetration defects. Since the PFA lining powder is a protective inner layer of industrial components made of soluble polytetrafluoroethylene (PFA) material, its main characteristics are strong corrosion resistance and high temperature resistance (-200℃ to 260℃). The prepared tank body and PFA lining powder need to be inspected according to the relevant regulations, "General Technical Conditions for Fluoroplastic Lined Equipment." Its density should conform to relevant standards (the density testing method for fluoroplastic materials is GB / T1033.1 or ASTM D792), and impurities are not allowed.

[0042] S2. Lay a diamond-shaped steel mesh on the inner surface of the tank in step S1 above, and then perform sandblasting again.

[0043] The process steps for laying and sandblasting the diamond-shaped steel mesh are as follows: First, the diamond-shaped steel mesh is welded. Then, the welded diamond-shaped steel mesh is laid to cover the entire inner surface of the tank. Next, it is welded using a CO2 gas shielded welding machine. After welding, it is sandblasted again. In this embodiment, the diamond-shaped steel mesh is welded manually. The 20*20*2mm diamond-shaped steel mesh is laid to cover the entire tank. It is welded manually using a CO2 gas shielded welding machine with 0.8mm welding wire, welding each intersection point. After welding, it is sandblasted again.

[0044] Sandblasting utilizes high-pressure compressed air generated by an air compressor to propel bearing steel grit from a spray gun at high speed onto the tank surface for rust removal, sandblasting, strengthening, or surface treatment. To further explain, in practical work, manual mechanized high-pressure sandblasting of the tank's inner metal surface can be performed by manually holding the spray gun inside the tank, sweeping back and forth across the inner surface to remove all grease, scale, rust products, and debris, achieving a uniform metallic color with a certain degree of roughness and no visible residue on the inner metal surface. The tank's inner metal surface should meet the Sa2 standard specified in HG / T 20679-2014, the Code for Design of External Corrosion Protection for Chemical Equipment and Pipelines. The technical requirements and standards must be met for the tank's metal shell to meet the requirements for roller coating. The air compressor used is a six-cubic-meter air compressor, which typically refers to a device with a discharge capacity of 6 cubic meters per minute. The mainstream power configuration is 37 kilowatts. Brands such as Yongbang, Denair, and Ingersoll Rand all supply this type of air compressor on the market. Specific models and prices need to be determined based on pressure requirements and brand configuration.

[0045] S3. Apply a primer to the inner surface of the tank in step S2 above.

[0046] a. Before applying the primer, the can in step S2 above needs to be cleaned. Specifically, a high-powered vacuum cleaner can be used to clean the residual sand and dust from the can.

[0047] b. Apply a primer to the can using a spraying device. The primer material is TC-11000, and it must be free of impurities. Before spraying, clean the surrounding environment, ensure the compressed air in the air compressor is free of water, connect the air hose to the spray gun, and spray the primer onto the entire inner surface of the can to enhance adhesion. Applying a primer refers to the process of spraying a layer of primer / base coat before the formal application of the topcoat or protective layer. The core functions of the primer are to enhance adhesion, prevent rust and corrosion, fill imperfections, and provide a uniform base for subsequent coatings. TC-11000 is a PFA (perfluoroalkoxy resin) based solvent-based primer manufactured by Daikin Japan, used as an adhesive undercoat for fluoropolymer (such as PTFE, PFA) powder coatings. The spraying equipment used is a manual electrostatic powder sprayer, which is easy for users to operate flexibly and adjust in real time, making the primer application process easier.

[0048] S4. After step S3 above, seal all the ports of the tank that has been sprayed with primer, leaving only the feeding port open.

[0049] In this process, a retaining ring made of sheet metal is placed on the outer edge of the flange sealing surface of the tank. A cover plate (sealing plate) is placed on top of the retaining ring and secured to the retaining ring with screws. After completion, each bolt hole must be checked to ensure that all gaps are sealed to prevent leakage. Only one feeding port is left on the tank, while all other pipe openings are sealed. In this embodiment, a thin strip of sheet metal (such as galvanized iron or tinplate) with a width of 5cm to 7cm is rolled into a ring structure, which facilitates subsequent installation. In this embodiment, all gaps are filled and sealed with waste fiberglass tape.

[0050] S5. After step S4 above, use tools to transport the can from step S3 above into the rotational molding furnace, and then fix the can to the rotational molding furnace with fixtures.

[0051] The process involves first installing the lower clamp in the rotational molding furnace. After the tank is transported into the furnace using tools, it is then clamped together using both the lower and upper clamps, and finally secured with welding rods to prevent it from falling off during rotation. The tool used is an overhead crane, a lifting device for transporting heavy objects, commonly known as a crane or hoist. The overhead crane is used to lift the tank into the rotational molding furnace.

[0052] S6. After step S5 above, close the door of the rotational molding furnace, and then control the heating temperature to the temperature at which the material can melt (generally 360℃~370℃). When the temperature is reached, add PFA lining powder (PFA raw material is PFA lining powder in step 1) through the reserved feeding port for processing.

[0053] Once the temperature is reached, PFA lining powder is added through the reserved feeding port. The tank in the rotational molding furnace is then immediately subjected to three-dimensional rotational coating for 2 hours to form the final product. The rotation inside the rotational molding furnace allows the PFA lining powder to reach every corner, such as pipe openings, manholes, and inner walls. This ensures that the tank is fully covered with PFA lining powder, achieving a seamless, one-time molding effect.

[0054] S7. Allow the tank body processed in step S6 to cool naturally, so that the PFA raw material inside the tank has completely solidified and formed the inner lining layer.

[0055] When the temperature naturally cools down to below 200℃, the door of the rotational molding furnace is opened. At this temperature, the inner lining layer formed by the PFA raw material can be completely solidified and molded.

[0056] S8. Remove the can from the rotational molding furnace in step S7 to obtain the finished product.

[0057] a. Use a cutting torch to cut open the reinforced block welded on the tank body in step S7 above, and remove the lower clamp and the upper clamp.

[0058] b. Use a crane to lift the tank out, use a wrench to remove the cover plate (sealing), and then remove the retaining ring.

[0059] S9. The tank body from step S8 above is reshaped.

[0060] After removing excess material from the tank using an electric cutter, a shaping machine is used to flatten the surface, leaving allowance according to the thickness required by the user. Then, a wool wheel is used to polish the surface to make it flat and smooth.

[0061] S10. Conduct an integrity test on the tank after step S9.

[0062] a. After the inner lining of the tank body is completed, an integrity test is required - an electric spark test is carried out in accordance with the "Test Method for Electric Spark of Fluoroplastic Lining". A 10Kv high-frequency electric spark detector is used. The probe moves slowly and continuously on the inner surface of the lining layer of the tank body at a speed not exceeding 100mm / s. If there is no intense spark, it is qualified. If it is unqualified, repairs are allowed and then the electric spark detection is carried out again. If it is non-conductive, it is qualified.

[0063] b. Visual inspection of the tank body - The inner surface of the lining layer of the tank body should be smooth and flat, without cracks or pores. It is judged whether it meets the standard by visual inspection.

[0064] S11. Finally, the qualified tank bodies in the above step S10 are packaged and shipped.

[0065] The reaction kettle made by the present invention has negative pressure resistance, high temperature resistance and corrosion resistance, and can be applied to the field of heavy corrosion prevention, with strong practicability. Compared with the spraying process in the prior art, it has the following:

[0066]

[0067] It can be seen that the reaction kettle with the spraying forming process in the prior art has a thin coating. In the present invention, through the process of adding a mesh and roll-coating PFA, the coating is thick, and it can withstand a pressure of -0.1 MPa to 0.4 MPa, a temperature range of 150°C to 250°C, and a coating thickness of 4 mm to 6 mm. It is more suitable for the field of heavy corrosion prevention. At a high temperature of 250 degrees, it has negative pressure resistance. The PFA roll-coating with a steel mesh process in the present invention can withstand a pressure of -0.1 to 0.4 MPa, a temperature range of 150°C - 250°C, and a coating thickness of 4 mm to 6 mm, and is more suitable for use in the environment in the field of heavy corrosion prevention.

[0068] The standard parts used in this application document can all be purchased from the market. The specific connection methods of each part all adopt conventional means such as bolts and rivets that are mature in the prior art. The switches, processors and the internal components of the manual powder electrostatic spraying machine all adopt conventional models in the prior art, and their internal structures belong to the prior art structures. Workers can complete the normal operation of them according to the prior art manuals. In addition, the circuit connection adopts the conventional connection method in the prior art, and no specific description will be made here.

[0069] It should be noted that although the above embodiments have been described in this article, the patent protection scope of the present invention is not limited thereby. Therefore, based on the innovative concept of the present invention, any changes and modifications made to the embodiments described in this article, or equivalent structural or equivalent process transformations made by using the content of the specification and drawings of the present invention, and directly or indirectly applying the above technical solutions to other related technical fields, are all included in the protection scope of the present invention patent.

Claims

1. A method for manufacturing a PFA anti-corrosion coating equipment with a screen coating, characterized in that, Includes the following steps: S1. Prepare the container and PFA lining powder in advance; S2. Lay a diamond-shaped steel mesh on the inner surface of the tank in step S1 above, and then perform sandblasting again. S3. Apply a primer to the inner surface of the container in step S2 above. S4. After step S3 above, seal all the openings of the container body that has been sprayed with primer, leaving only one feeding port. S5. After step S4 above, use tools to transport the container body from step S3 above into the rotational molding furnace, and then fix the container body to the rotational molding furnace with fixtures. S6. After step S5 above, close the door of the rotational molding furnace, and then control the heating temperature to the temperature at which the material can melt. When the temperature is reached, add PFA lining powder through the reserved feeding port for processing. S7. Allow the container body processed in step S6 to cool naturally, so that the PFA raw material inside the container body has completely solidified and formed the inner lining layer. S8. Remove the container from the rotational molding furnace in step S7 to obtain the finished product.

2. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 1, characterized in that: The container body mentioned in step S1 needs to be sandblasted. The prepared container body and PFA lining powder need to be inspected according to relevant regulations, and their density should meet the standards.

3. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 1, characterized in that: In step S2, firstly, diamond-shaped steel mesh is welded, then the welded diamond-shaped steel mesh is laid to cover the entire inner surface of the tank. Next, it is welded using a CO2 gas shielded welding machine, and then sandblasted again after welding.

4. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 3, characterized in that: Sandblasting is a process that uses high-pressure compressed air generated by an air compressor to propel bearing steel sand from a spray gun at high speed onto the surface of a container for rust removal, sand cleaning, strengthening, or surface treatment.

5. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 1, characterized in that: Before applying the primer, the container body in step S2 above needs to be thoroughly cleaned. Then, the primer is applied to the container body using a spray gun, and the primer needs to cover the entire inner surface of the container.

6. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 5, characterized in that: Use a high-powered vacuum cleaner to clean the container of residual sand and dust.

7. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 1, characterized in that: In step S5 above, the lower clamp is first installed in the rotational molding furnace. After the container body is hoisted into the rotational molding furnace by tools, the container body is then clamped by the lower clamp and the upper clamp, and finally welded in place with welding rods.

8. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 1, characterized in that: In step S6 above, the material can melt at a temperature of 360℃~370℃.

9. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 1, characterized in that: In step S6 above, after reaching the required temperature, PFA lining powder is added through the reserved feeding port. The container body in the rotational molding furnace is then immediately subjected to three-dimensional rotational coating for 2 hours to form the product. The rotation inside the rotational molding furnace allows the PFA lining powder to reach every corner, achieving one-time molding.

10. The method for manufacturing PFA anti-corrosion equipment by roller coating as described in claim 1, characterized in that: After step S8 above, the processed container body needs to undergo shaping and integrity testing in sequence, and only after passing the final test can it officially become a product.

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