Double-wall corrugated pipe with good corrosion-resistant effect

Abstract

The utility model relates to the technical field of double-wall corrugated pipes, in particular to a double-wall corrugated pipe with a good corrosion-resistant effect, which comprises an outer pipe and an inner pipe, a cavity is formed between the outer pipe and the inner pipe, the outer surface of the outer pipe is coated with a corrosion-resistant coating, the inner surface of the inner pipe is coated with an anti-sticking layer, and the seam of the outer pipe and the inner pipe is sealed by a sealing ring. The corrosion-resistant coating is composed of multiple layers of different materials and comprises a bottom coating, a middle coating and a surface coating, and the anti-sticking layer is a polytetrafluoroethylene (PTFE) coating. The outer pipe and the inner pipe are both made of high-density polyethylene (HDPE). The double-wall corrugated pipe further comprises reinforcing ribs and protrusions which are arranged on the outer surface of the outer pipe, connecting pieces are arranged at the two ends of the outer pipe, and supporting ribs are arranged in the cavity. The service life of the double-wall corrugated pipe in a high-corrosion environment can be prolonged, and meanwhile the mechanical strength and the pressure bearing capacity of the double-wall corrugated pipe are enhanced.

Description

Technical Field

[0001] This utility model belongs to the field of pipeline technology, specifically a double-wall corrugated pipe with good corrosion resistance. Background Technology

[0002] In pipeline engineering, double-wall corrugated pipes are widely used in underground drainage, sewage, and ventilation due to their excellent mechanical properties and long service life. Traditional double-wall corrugated pipes are mainly made of polyethylene (PE) or polyvinyl chloride (PVC), which exhibit good corrosion resistance under normal conditions. However, in some special environments, such as soils with strong acid and alkali corrosion or industrial wastewater discharge systems with high chemical content, traditional double-wall corrugated pipes are prone to corrosion, leading to a shortened service life and even pipe rupture and leakage, posing potential risks to project safety. Furthermore, existing double-wall corrugated pipes often lack effective anti-corrosion treatment measures during manufacturing, further exacerbating corrosion problems in harsh environments. Therefore, developing a double-wall corrugated pipe with good corrosion resistance to improve its stability and service life in harsh environments has significant practical importance and application value. Utility Model Content

[0003] The purpose of this invention is to provide a double-wall corrugated pipe with good corrosion resistance, which solves the problem of short service life of existing double-wall corrugated pipes in highly corrosive environments, and has excellent corrosion resistance and technical effect.

[0004] A double-wall corrugated pipe with good corrosion resistance includes an outer pipe and an inner pipe, forming a cavity between them. The outer surface of the outer pipe is coated with a corrosion-resistant coating, and the inner surface of the inner pipe is coated with an anti-sticking layer. The joint between the outer and inner pipes is sealed with a sealing ring. The corrosion-resistant coating consists of multiple layers of different materials, including a primer, an intermediate coating, and a topcoat. The primer is epoxy resin, the intermediate coating is polyurethane, and the topcoat is fluorocarbon resin. The anti-sticking layer is a polytetrafluoroethylene coating. Both the outer and inner pipes are made of high-density polyethylene (HDPE).

[0005] The double-walled corrugated pipe also includes reinforcing ribs on the outer surface of the outer pipe. The reinforcing ribs are spirally distributed and are made of glass fiber reinforced plastic (FRP). The outer surface of the outer pipe also has several protrusions, which are evenly distributed between the reinforcing ribs. The protrusions are also made of glass fiber reinforced plastic (FRP) and have a height of 1-2 mm.

[0006] It also includes connectors located at both ends of the double-walled corrugated pipe. The connectors include circular flanges and sealing gaskets. The circular flanges have several fixing holes with a diameter of 10-15mm. The sealing gaskets are made of nitrile rubber and have a thickness of 5-8mm. The outer diameter of the sealing gasket matches the inner diameter of the circular flange.

[0007] The thickness of the corrosion-resistant coating is 0.3-0.5 mm, and the thickness of the anti-stick layer is 0.1-0.2 mm. The spiral spacing of the reinforcing ribs is 10-20 mm, and the width of the reinforcing ribs is 5-10 mm.

[0008] The double-wall corrugated pipe also includes support ribs installed within the cavity. These support ribs are corrugated and made of fiberglass reinforced plastic (FRP), with a height of 2-3 mm. The support ribs help improve the pressure-bearing capacity of the double-wall corrugated pipe and prevent deformation of the inner and outer pipes under high pressure.

[0009] This utility model designs a double-wall corrugated pipe with good corrosion resistance, which not only improves the service life of the double-wall corrugated pipe in highly corrosive environments, but also improves the mechanical strength and pressure bearing capacity of the double-wall corrugated pipe by setting reinforcing ribs and supporting ribs, thus having multiple technical effects. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of the double-walled corrugated pipe in an embodiment of this utility model.

[0011] Figure 2 This is a cross-sectional structural diagram of the double-walled corrugated pipe in an embodiment of this utility model.

[0012] Figure 3 This is a partial enlarged view of the outer surface of the double-walled corrugated pipe in an embodiment of this utility model.

[0013] Figure 4 This is a schematic diagram of the structure of the double-walled corrugated pipe connector in an embodiment of this utility model.

[0014] The reference numerals in the attached drawings are as follows: 1. Outer tube; 2. Inner tube; 3. Cavity; 4. Corrosion-resistant coating; 5. Anti-stick layer; 6. Sealing ring; 7. Reinforcing rib; 8. Protrusion; 9. Connector; 91. Circular flange; 92. Fixing hole; 93. Sealing gasket; 10. Support rib. Detailed Implementation

[0015] This utility model provides a double-wall corrugated pipe with good corrosion resistance, aiming to solve the problem of short service life of existing double-wall corrugated pipes in highly corrosive environments. By optimizing the materials and coatings of the inner and outer pipes, and by setting reinforcing ribs and supporting ribs, the corrosion resistance and mechanical strength of the double-wall corrugated pipe are significantly improved. The following is in conjunction with the appendix... Figure 1 To be continued Figure 4 The specific embodiments of this utility model are described in detail.

[0016] First, refer to the appendix Figure 1 and attached Figure 2The double-wall corrugated pipe of this invention includes an outer pipe 1 and an inner pipe 2, with a cavity 3 formed between the outer pipe 1 and the inner pipe 2. Both the outer pipe 1 and the inner pipe 2 are made of high-density polyethylene (HDPE), which has good weather resistance and mechanical strength and can effectively resist the influence of various environmental factors. The outer surface of the outer pipe 1 is coated with a corrosion-resistant coating 4, and the inner surface of the inner pipe 2 is coated with an anti-sticking layer 5.

[0017] Specifically, the corrosion-resistant coating 4 consists of multiple layers of different materials, including a primer, intermediate coating, and topcoat. The primer is epoxy resin with a thickness of 0.2 mm. Epoxy resin has excellent adhesion and can effectively adhere to the surface of the outer tube 1, forming a preliminary protective layer. The intermediate coating is polyurethane with a thickness of 0.1 mm. Polyurethane has good flexibility and chemical corrosion resistance, which can further improve the corrosion resistance of the coating. The topcoat is fluorocarbon resin with a thickness of 0.2 mm. Fluorocarbon resin has extremely high chemical stability and weather resistance, which can effectively resist the erosion of various corrosive media and extend the service life of the double-walled corrugated pipe.

[0018] The anti-stick layer 5 is a polytetrafluoroethylene (PTFE) coating with a thickness of 0.15 mm. PTFE has an extremely low coefficient of friction and good anti-stick properties, which can effectively prevent the medium being transported in the inner tube 2 from adhering to the tube wall, reduce medium loss during transmission, and improve transmission efficiency.

[0019] The joint between the outer tube 1 and the inner tube 2 is sealed with a sealing ring 6 made of nitrile rubber with a thickness of 6mm. Nitrile rubber has good oil and corrosion resistance, effectively preventing external corrosive media from entering the cavity 3 of the double-walled corrugated pipe, thus protecting the inner tube 2 from corrosion. The outer diameter of the sealing ring 6 matches the joint between the outer tube 1 and the inner tube 2, ensuring the reliability and effectiveness of the seal.

[0020] To improve the mechanical strength and pressure-bearing capacity of the double-walled corrugated pipe, this invention incorporates reinforcing ribs 7 on the outer surface of the outer pipe 1. The reinforcing ribs 7 are spirally distributed with a spacing of 15 mm and a width of 8 mm, and are made of glass fiber reinforced plastic (FRP). Glass fiber reinforced plastic possesses excellent mechanical properties and corrosion resistance, effectively enhancing the strength of the outer pipe 1 and preventing deformation under high pressure. (See attached figure.) Figure 3 The outer surface of the outer tube 1 is also provided with several protrusions 8, which are evenly distributed between the reinforcing ribs 7. The material is also glass fiber reinforced plastic (FRP), and the height is 1.5mm. These protrusions 8 not only increase the roughness of the outer tube 1 and improve its friction with soil or other external media, but also further enhance the overall structural stability of the double-wall corrugated pipe.

[0021] The double-walled corrugated pipe has connectors 9 at both ends. Connector 9 includes a circular flange 91, a fixing hole 92, and a sealing gasket 93. (See attached diagram.) Figure 4 The circular flange 91 has eight fixing holes 92, each 12mm in diameter. These holes are used to bolt the double-walled bellows to other pipes or equipment, ensuring a secure and reliable connection. The sealing gasket 93 is made of nitrile rubber, 7mm thick, and its outer diameter matches the inner diameter of the circular flange 91. The function of the sealing gasket 93 is to provide a seal during connection, preventing media leakage and resisting the intrusion of external corrosive media.

[0022] To further improve the pressure-bearing capacity of the double-wall corrugated pipe, this invention incorporates a support rib 10 within the cavity 3. The support rib 10 is corrugated, made of fiberglass reinforced plastic (FRP), and has a height of 2.5 mm. The support rib 10 not only enhances the internal structural stability of the double-wall corrugated pipe, preventing deformation of the inner and outer pipes under high pressure, but also effectively disperses pressure within the pipe, thereby improving its load-bearing capacity. The corrugated shape of the support rib 10 provides good elasticity under pressure, enabling it to absorb and buffer external pressure to a certain extent, thus extending the service life of the double-wall corrugated pipe.

[0023] In specific implementation, the production steps of double-wall corrugated pipes are as follows:

[0024] Fabrication of Outer Tube 1 and Inner Tube 2: First, outer tube 1 and inner tube 2 are fabricated using high-density polyethylene (HDPE) material through an extrusion molding process. The wall thickness of outer tube 1 and inner tube 2 is adjusted according to the actual usage environment and pressure requirements; generally, the wall thickness of outer tube 1 is 3-5mm, and the wall thickness of inner tube 2 is 2-4mm. After fabrication, outer tube 1 and inner tube 2 are fitted together to form the main structure of the double-walled corrugated pipe, ensuring that the cavity 3 between the inner and outer tubes has good sealing performance.

[0025] Application of the corrosion-resistant coating 4: The outer surface of the outer tube 1 is pretreated to remove grease and impurities, improving coating adhesion. Then, a primer, intermediate coating, and topcoat are applied using a spraying process. The primer is epoxy resin with a thickness of 0.2 mm after spraying; the intermediate coating is polyurethane with a thickness of 0.1 mm after spraying; and the topcoat is fluorocarbon resin with a thickness of 0.2 mm after spraying. After coating, the outer tube 1 is placed in an oven for curing to ensure optimal adhesion and corrosion resistance between the coating and the outer tube 1.

[0026] Coating of the anti-stick layer 5: The inner surface of the inner tube 2 is pretreated to remove grease and impurities, improving the adhesion of the coating. Then, a polytetrafluoroethylene (PTFE) coating with a thickness of 0.15 mm is applied by spraying or dip coating. After coating, the inner tube 2 is placed in an oven for curing to ensure optimal adhesion and anti-stick performance between the coating and the inner tube 2.

[0027] Installation of sealing ring 6: Clean the joint between outer tube 1 and inner tube 2 thoroughly, ensuring there are no impurities or grease. Then, install the nitrile rubber sealing ring 6 at the joint between outer tube 1 and inner tube 2, ensuring that the outer diameter of the sealing ring 6 matches the size of the joint. After installation, conduct a sealing performance test to ensure a good seal at the joint.

[0028] Installation of Reinforcing Ribs 7 and Protrusions 8: The required reinforcing ribs 7 and protrusions 8 are manufactured from fiberglass reinforced plastic (FRP) using molding or injection molding processes. The reinforcing ribs 7 are spirally distributed with a spiral spacing of 15mm and a width of 8mm. The reinforcing ribs 7 are evenly arranged along the outer surface of the outer tube 1 and fixed to the outer tube 1 by bonding or welding. The protrusions 8 are evenly distributed between the reinforcing ribs 7, with a height of 1.5mm, and are also fixed to the outer surface of the outer tube 1 by bonding or welding. After installing the reinforcing ribs 7 and protrusions 8, a mechanical strength test is performed to ensure that the double-walled corrugated pipe will not deform or be damaged under high pressure.

[0029] Installation of support ribs 10: Corrugated support ribs 10, with a height of 2.5mm, are made of glass fiber reinforced plastic (FRP) through molding or injection molding. The support ribs 10 are evenly distributed within the cavity 3 of the double-wall corrugated pipe and fixed by bonding or welding. After installing the support ribs 10, a pressure-bearing capacity test is conducted to ensure that the double-wall corrugated pipe will not deform or be damaged during high-pressure media transmission.

[0030] Installation of connector 9: Install the circular flange 91 and sealing gasket 93 at both ends of the double-wall bellows. The circular flange 91 has eight fixing holes 92, each with a diameter of 12mm. During installation, ensure that the outer diameter of the sealing gasket 93 matches the inner diameter of the circular flange 91. After installation, conduct a connection performance test to ensure the reliability and sealing of the double-wall bellows connection with other pipes or equipment.

[0031] This novel double-wall corrugated pipe is suitable for media transmission in various highly corrosive environments, such as chemical plants, sewage treatment plants, and marine engineering projects. Specific application scenarios are as follows:

[0032] In chemical plants, double-wall corrugated pipes are used to transport various chemical raw materials and products. Due to the strong corrosiveness of chemical media, traditional double-wall corrugated pipes are prone to corrosion of both the outer and inner pipes after a period of use, thus affecting their service life. This invention's double-wall corrugated pipe, by incorporating a corrosion-resistant coating 4 and an anti-sticking layer 5, effectively resists corrosion from chemical media, extending its service life. Simultaneously, the addition of reinforcing ribs 7 and supporting ribs 10 improves the mechanical strength and pressure-bearing capacity of the double-wall corrugated pipe, ensuring that it will not deform or be damaged during high-pressure transmission, thus enhancing the reliability of transmission.

[0033] In wastewater treatment plants, double-wall corrugated pipes are used to transport highly corrosive wastewater and sludge. Because wastewater and sludge contain a large amount of corrosive substances, traditional double-wall corrugated pipes are easily corroded during use, thus affecting their service life. This invention's double-wall corrugated pipe, by incorporating a corrosion-resistant coating 4 and an anti-sticking layer 5, can effectively resist corrosive substances in wastewater and sludge, extending its service life. Simultaneously, the addition of reinforcing ribs 7 and supporting ribs 10 improves the mechanical strength and pressure-bearing capacity of the double-wall corrugated pipe, ensuring that it will not deform or be damaged during high-pressure transmission, thus improving the reliability of transmission.

[0034] In marine engineering, double-wall corrugated pipes are used for the construction of subsea pipelines. Due to the strong corrosiveness of seawater, traditional double-wall corrugated pipes are easily corroded during use, thus affecting their service life. This invention's double-wall corrugated pipe, by incorporating a corrosion-resistant coating 4 and an anti-sticking layer 5, can effectively resist corrosive substances in seawater, extending its service life. Simultaneously, the addition of reinforcing ribs 7 and supporting ribs 10 improves the mechanical strength and pressure-bearing capacity of the double-wall corrugated pipe, ensuring that it will not deform or be damaged during high-pressure seawater transmission, thus improving the reliability of transmission.

[0035] Through the detailed description of the above embodiments and application scenarios, the double-wall corrugated pipe of this utility model not only has excellent corrosion resistance, but also significantly improves mechanical strength and pressure bearing capacity through the setting of reinforcing ribs 7 and supporting ribs 10, thus possessing broad application prospects and market value.

[0036] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A double-wall corrugated pipe with good corrosion resistance, comprising an outer pipe (1) and an inner pipe (2), a cavity (3) being formed between the outer pipe (1) and the inner pipe (2), characterized in that: the outer surface of the outer pipe (1) is coated with a corrosion-resistant coating (4), and the inner surface of the inner pipe (2) is coated with an anti-sticking layer (5); the joint between the outer pipe (1) and the inner pipe (2) is sealed with a sealing ring (6); the corrosion-resistant coating (4) is composed of a primer layer, an intermediate layer and a top layer, the primer layer is epoxy resin, the intermediate layer is polyurethane, and the top layer is fluorocarbon resin; the anti-sticking layer (5) is a polytetrafluoroethylene coating; the materials of the outer pipe (1) and the inner pipe (2) are both high-density polyethylene.

2. The thickness of the corrosion-resistant coating (4) is 0.3-0.5 mm.

3. The thickness of the anti-sticking layer (5) is 0.1-0.2 mm.

4. The outer surface of the outer pipe (1) is further provided with reinforcing ribs (7), which are distributed in a spiral shape and made of glass fiber reinforced plastic.

5. The spiral pitch of the reinforcing ribs (7) is 10-20 mm, and the width is 5-10 mm.

6. The outer surface of the outer pipe (1) is further provided with a plurality of protrusions (8), which are uniformly distributed between the reinforcing ribs (7) and made of glass fiber reinforced plastic, with a height of 1-2 mm.

2. The corrosion-resistant double-wall corrugated pipe according to claim 1, characterized in that, 7. The double-wall corrugated pipe further comprises connecting pieces (9) arranged at both ends of the double-wall corrugated pipe, the connecting pieces (9) comprising a circular flange (91) and a sealing gasket (93), the circular flange (91) being provided with a plurality of fixing holes (92), and the sealing gasket (93) being made of nitrile rubber with a thickness of 5-8 mm and an outer diameter matching the inner diameter of the circular flange (91).

3. The corrosion-resistant double-wall corrugated pipe according to claim 1, characterized in that, 8. The cavity (3) is further provided with support ribs (10), which are corrugated and made of glass fiber reinforced plastic with a height of 2-3 mm.

4. The corrosion-resistant double-wall corrugated pipe according to claim 1, characterized in that, 9. The support ribs (10) help to improve the pressure-bearing capacity of the double-wall corrugated pipe and prevent the inner and outer pipes from deforming under high pressure.

5. The corrosion-resistant double-wall corrugated pipe according to claim 4, characterized in that, ​ 6. The corrosion resistant double wall corrugated pipe according to claim 4, wherein ​ 7. The corrosion-resistant double-wall corrugated pipe according to claim 1, characterized in that, ​ 8. The corrosion resistant double wall corrugated pipe according to claim 1, wherein, ​ 9. The corrosion-resistant double-wall corrugated pipe according to claim 8, characterized in that, ​

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