Inspection well with inner surface coated with epoxy resin and production process of inspection well

Abstract

The inspection well with the inner surface coated with epoxy resin comprises a well base, a well body is installed at the top of the well base, the well body comprises a lower well cylinder, a connecting well cylinder and an upper well cylinder which are sequentially distributed and installed from bottom to top, and the lower well cylinder and the well base are of an integrated pouring forming structure; a plurality of pipeline connectors are evenly arranged on the lower portion of the side wall of the lower shaft in the circumferential direction, connecting pipelines are installed in the pipeline connectors, the connecting shaft is installed at the top of the lower shaft, the upper shaft is installed at the top of the connecting shaft, a well lid is installed at the top of the upper shaft, and an epoxy resin coating is arranged on the inner side of the well body and comprises an inner side transition coating. The outer side of the inner side transition coating is coated with a middle anti-corrosion coating, and the outer side of the middle anti-corrosion coating is coated with a surface abrasion-resistant coating.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inspection wells, and particularly relates to an inspection well with an inner surface coated with epoxy resin and a production process thereof. BACKGROUND

[0002] With the rapid advancement of urbanization, the scale of urban infrastructure construction continues to expand, and various pipeline systems such as rainwater and sewage drainage, gas transportation, and power communication have become the "lifeline" to ensure the normal operation of the city. In order to achieve daily maintenance, repair, and fault handling of the pipeline, a large number of inspection wells are set at key nodes along the pipeline, and their performance directly determines the operational stability of the urban pipeline system.

[0003] At present, reinforced concrete inspection wells have become the most widely used type of inspection well in urban construction due to their low construction cost, high overall strength of the well body, and strong stability during long-term use, accounting for more than 80% of the total market application. However, the ordinary Portland cement concrete material used in ordinary reinforced concrete inspection wells has poor shrinkage, and microcracks are easily generated after pouring and forming due to water evaporation. With the influence of environmental factors such as temperature changes and soil settlement, the microcracks gradually expand into macrocracks. At the same time, the city's rainwater and sewage contain a large amount of acidic substances and corrosive ions, which can penetrate into the interior of the concrete and react with the cement hydration products, causing the concrete surface to peel off and the internal steel to rust, thereby causing the well body structure to deform and leak, shortening the service life of the inspection well, increasing the maintenance cost, and possibly causing safety hazards such as underground pipeline blockage and road collapse, seriously affecting the normal operation of the urban drainage system and the daily life of residents. Therefore, an inspection well with an inner surface coated with epoxy resin and a production process thereof are urgently needed to solve the above problems. SUMMARY

[0004] In view of the problems in the above background art, the purpose of the present application is to provide an inspection well with an inner surface coated with epoxy resin and a production process thereof.

[0005] To achieve the above technical purpose, the technical solution adopted by the present application is as follows: An inspection well with an epoxy resin coating on its inner surface includes a well base, a well body mounted on top of the well base, and the well body comprising a lower well cylinder, a connecting well cylinder, and an upper well cylinder arranged sequentially from bottom to top. The lower well cylinder and the well base are integrally cast and molded. Several pipe interfaces are evenly arranged along the circumferential direction on the lower side wall of the lower well cylinder, and connecting pipes are installed in the pipe interfaces. The connecting well cylinder is installed on top of the lower well cylinder, and the upper well cylinder is installed on top of the connecting well cylinder. A well cover is installed on top of the upper well cylinder. The inner side of the well body is provided with an epoxy resin coating, which includes an inner transition coating, an intermediate anti-corrosion coating on the outer side of the inner transition coating, and a surface wear-resistant coating on the outer side of the intermediate anti-corrosion coating.

[0006] Furthermore, the pipe interface and the lower shaft are integrally cast and molded, and the inner side of the pipe interface is flush with the inner wall of the lower shaft. This structural design facilitates manufacturing.

[0007] Furthermore, the axis of the connecting pipe is perpendicular to the axis of the lower shaft, and the inner diameter of the connecting pipe matches the outer diameter of the urban pipeline to be connected. This structural design facilitates connection with urban pipelines.

[0008] Furthermore, the inner transition coating is manufactured using a mixture of epoxy resin and silane coupling agent, the intermediate anti-corrosion coating is manufactured using a composite coating of epoxy resin and glass fiber, and the surface wear-resistant coating is manufactured using a mixture of epoxy resin and alumina powder. This structural design achieves a sealing and corrosion-resistant effect.

[0009] Furthermore, the bottom of the well base is equipped with several fixing piles, and the surface of the fixing piles is provided with several barbs. This structural design improves the effect of fixed installation.

[0010] Furthermore, positioning rods are installed on all four sides of the well base surface, and positioning holes matching the positioning rods are provided in the lower well casing, connecting well casing, and upper well casing. This structural design achieves the effect of positioning and installation.

[0011] Furthermore, the top of the upper well casing is provided with an annular assembly groove, and an assembly base is installed within the annular assembly groove. The top of the assembly base is fixedly installed on the bottom of the well cover. This structural design facilitates the positioning and installation of the well cover.

[0012] Furthermore, an annular mounting frame is installed on the inner side of the upper shaft, and a fall-prevention net is installed inside the annular mounting frame. This structural design provides a fall-prevention effect.

[0013] Furthermore, the lower shaft has a mating groove at its top, the upper shaft has a mating protrusion at its bottom that matches the mating groove, the connecting shaft has a connecting protrusion on its lower side that matches the mating groove, and the connecting shaft has a connecting groove at its top that matches the mating protrusion. This structural design further enhances the effectiveness of positioning, connection, and installation.

[0014] A manufacturing process for inspection wells with an inner surface coated with epoxy resin, characterized by the following steps: S1: Prefabrication of the well body. The steel reinforcement skeleton of the well body (including the reinforcement of the well cover, the reinforcement of the well seat, the reinforcement of the pipe interface and the reinforcement of the positioning hole) is tied according to the design dimensions. The steel reinforcement skeleton is placed into a customized cylindrical mold. Ordinary Portland cement, crushed stone, sand and water are mixed in the mass ratio to prepare concrete. The concrete is poured into the mold, vibrated to compact it, and then cured. After curing, the mold is removed to obtain the prefabricated well body. S2: Surface pretreatment, grinding the inner wall of the precast well body to remove surface laitance, burrs and impurities. After grinding, the surface is rinsed with a high-pressure water gun and then dried with compressed air to ensure surface dryness. S3: Preparation of epoxy resin coating Preparation of inner transition coating: Epoxy resin, silane coupling agent and diluent are mixed in mass ratio and stirred evenly to obtain inner transition coating. The inner transition coating is evenly coated on the pretreated well body wall using a high-pressure airless sprayer. After coating, it is allowed to stand and cure to form inner transition coating. Preparation of intermediate anti-corrosion coating: Epoxy resin, glass fiber, curing agent and toughening agent are mixed in mass ratio and stirred evenly to obtain intermediate anti-corrosion coating. The intermediate anti-corrosion coating is evenly applied to the inner transition coating surface by scraping. During the scraping process, it is ensured that the coating is evenly filled and there are no bubbles or missed coating. After coating, it is allowed to stand and cure to form intermediate anti-corrosion coating. Preparation of surface wear-resistant coating: Epoxy resin, alumina powder, curing agent and diluent are mixed in mass ratio and stirred evenly to obtain surface wear-resistant coating; the surface wear-resistant coating is evenly coated on the surface of intermediate anti-corrosion coating by roller coating, and then allowed to stand for curing to form surface wear-resistant coating. S4: Manhole cover installation. Place the manhole cover over the upper manhole casing to complete the overall production and assembly of the inspection manhole.

[0015] The beneficial effects of this invention are as follows: By coating the inner wall of the well body with an epoxy resin coating, and using a mixture of epoxy resin and silane coupling agent for the inner transition coating, the adhesion between the coating and the well body is enhanced, and tiny gaps on the concrete surface are filled, blocking the penetration path of corrosive media. The intermediate anti-corrosion coating is made of epoxy resin and glass fiber composite. The excellent anti-permeability of glass fiber and the anti-corrosion properties of epoxy resin work synergistically to effectively resist the erosion of the well body by acidic substances, corrosive ions in urban rainwater and sewage, and chemicals in the soil, preventing the concrete surface from peeling off and the internal steel reinforcement from rusting. The surface wear-resistant coating adds alumina powder, which has high hardness and strong wear resistance, and can resist friction and collision during installation and use, preventing the coating from being damaged and exposing the internal anti-corrosion layer, ensuring the integrity of the anti-corrosion system, improving the corrosion resistance and load-bearing performance of ordinary concrete inspection wells, and solving the problems of well body deformation and leakage caused by corrosion and cracks in ordinary inspection wells. Attached Figure Description

[0016] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings; Figure 1 This is a schematic diagram of the axial side structure of a manhole with an inner surface coated with epoxy resin, according to an embodiment of the present invention. Figure 2 This is a schematic cross-sectional view of a manhole with an inner surface coated with epoxy resin, according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the positioning rod connection structure of a manhole with an inner surface coated with epoxy resin, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the epoxy resin coating structure of an inspection well with an inner surface coated with epoxy resin, according to an embodiment of the present invention. The symbols for the main components are explained below: 1. Well base; 2. Well body; 3. Lower well casing; 4. Connecting well casing; 5. Upper well casing; 6. Pipe interface; 7. Connecting pipe; 8. Well cover; 9. Epoxy resin coating; 10. Inner transition coating; 11. Intermediate anti-corrosion coating; 12. Surface wear-resistant coating; 13. Fixing pile; 14. Barb; 15. Positioning rod; 16. Positioning hole; 17. Annular assembly groove; 18. Assembly seat; 19. Annular mounting bracket; 20. Fall protection net; 21. Butt joint groove; 22. Butt joint protrusion; 23. Connecting protrusion; 24. Connecting groove. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] Example 1, such as Figure 1 , Figure 2 and Figure 4As shown, an inspection well with an inner surface coated with epoxy resin has a well body 2 installed on top of a well base 1. The well body 2 includes a lower well cylinder 3, a connecting well cylinder 4, and an upper well cylinder 5 installed sequentially from bottom to top. The lower well cylinder 3 and the well base 1 are integrally cast and molded. Several pipe interfaces 6 are evenly arranged along the circumferential direction on the lower part of the side wall of the lower well cylinder 3. Connecting pipes 7 are installed in the pipe interfaces 6. The connecting well cylinder 4 is installed on top of the lower well cylinder 3. The upper well cylinder 5 is installed on top of the connecting well cylinder 4. A well cover 8 is installed on top of the upper well cylinder 5. The inner side of the well body 2 is provided with an epoxy resin coating 9. The epoxy resin coating 9 includes an inner transition coating 10, an outer intermediate anti-corrosion coating 11, and an outer surface wear-resistant coating 12.

[0019] In this embodiment, during production, the reinforcing steel skeleton of the well body, including the well cover steel skeleton, well seat steel skeleton, pipe interface steel skeleton, and positioning hole steel skeleton, is tied according to the design dimensions. The reinforcing steel skeleton is placed in a customized cylindrical mold. Concrete is prepared by mixing ordinary silicate cement, crushed stone, sand, and water in a certain mass ratio. The concrete is poured into the mold, vibrated to compact it, and then cured. The curing temperature is 20-25℃, the curing humidity is not less than 90%, and the curing time is 28 days. After curing, the mold is removed, resulting in the well seat 1, lower well cylinder 3, connecting well cylinder 4, upper well cylinder 5, and well cover 8. The surfaces of these components are pretreated. After pretreatment, an epoxy resin coating 9 is applied to the inner walls of the lower well cylinder 3, connecting well cylinder 4, and upper well cylinder 5 to improve the corrosion resistance and load-bearing performance of the ordinary concrete inspection well.

[0020] Example 2, as Figure 1 and Figure 2 As shown, this embodiment adds the following structure to the embodiment 1: the pipe interface 6 and the lower shaft 3 are integrally cast and molded, and the inner side of the pipe interface 6 is flush with the inner wall of the lower shaft 3.

[0021] In this embodiment, the pipe interface 6 and the lower well casing 3 are integrally cast, which greatly simplifies the production process and effectively improves production efficiency. At the same time, the flush inner wall structure design can avoid protrusions or depressions at the connection between the pipe interface 6 and the lower well casing 3, ensuring that the fluid flows smoothly in the well casing.

[0022] Example 3, as Figure 1 and Figure 2 As shown, this embodiment adds the following structure based on embodiment 1: the axis of the connecting pipe 7 is perpendicular to the axis of the lower well 3, and the inner diameter of the connecting pipe 7 matches the outer diameter of the urban pipeline to be connected.

[0023] In this embodiment, the connecting pipe 7 can achieve precise docking with the urban pipeline without the need for complex angle adjustments, reducing construction difficulty and ensuring a tight fit between the connecting pipe 7 and the urban pipeline, effectively avoiding gaps at the connection point and reducing the risk of water leakage and seepage at the pipe connection.

[0024] Example 4, as Figure 4 As shown, this embodiment adds the following structure based on embodiment 1: the inner transition coating 10 is made of a mixed coating of epoxy resin and silane coupling agent, the intermediate anti-corrosion coating 11 is made of a composite coating of epoxy resin and glass fiber, and the surface wear-resistant coating 12 is made of a mixed coating of epoxy resin and alumina powder.

[0025] In this embodiment, the inner transition coating 10 enhances the adhesion between the coating and the well body 2, effectively fills the tiny gaps on the surface of the well body 2, and improves the inner sealing performance. At the same time, the presence of epoxy resin provides basic anti-corrosion protection for the inner side. The glass fiber of the intermediate anti-corrosion coating 11 has excellent resistance to the penetration of corrosive media. It works synergistically with epoxy resin to form a strong anti-corrosion barrier, which can resist the erosion of the well barrel by various corrosive substances in groundwater and chemicals in the soil, and significantly extend the service life of the well body 2. The alumina powder in the surface wear-resistant coating 12 has high hardness and strong wear resistance, which can effectively resist the external forces such as friction and collision that the well barrel is subjected to during installation and use, and avoid the exposure of the internal anti-corrosion layer due to damage to the surface coating, thereby ensuring the integrity of the anti-corrosion system of the well body 2 and ensuring that the well body 2 maintains a good sealing and anti-corrosion state for a long time.

[0026] Example 5, as Figure 2 As shown, this embodiment adds the following structure to the embodiment 1: several fixing piles 13 are installed at the bottom of the well base 1, and several barbs 14 are provided on the surface of the fixing piles 13.

[0027] In this embodiment, during installation, after the fixing pile 13 is inserted into the soil, the barbs 14 can tightly interlock with the surrounding soil, greatly enhancing the friction and pull-out resistance between the fixing pile 13 and the soil, preventing the fixing pile 13 from loosening or being pulled out under the influence of external forces, and further strengthening the fixing effect of the well base 1.

[0028] Example 6, as Figure 3 As shown, this embodiment adds the following structure based on embodiment 1: positioning rods 15 are installed on the four sides of the surface of the well base 1, and positioning holes 16 that match the positioning rods 15 are provided in the lower well tube 3, the connecting well tube 4 and the upper well tube 5.

[0029] In this embodiment, during the assembly of the well body 2, the cooperation between the positioning rod 15 and the positioning hole 16 can quickly determine the relative positions between the components, avoid problems such as component misalignment and offset during assembly, and ensure precise docking and installation between the lower well casing 3, the connecting well casing 4 and the upper well casing 5 and the well base 1.

[0030] Example 7, as Figure 2 As shown, this embodiment adds the following structure based on embodiment 1: the top of the upper well casing 5 is provided with an annular assembly groove 17, and an assembly base 18 is installed in the annular assembly groove 17. The top of the assembly base 18 is fixedly installed on the bottom of the well cover 8.

[0031] In this embodiment, during installation, the annular assembly groove 17 provides a precise installation positioning space for the assembly base 18, enabling the assembly base 18 to be quickly and accurately installed on the top of the upper well casing 5, thus preventing the well cover 8 from shifting or misaligning during installation.

[0032] Example 8, as Figure 2 As shown, this embodiment adds the following structure to the embodiment 1: an annular mounting frame 19 is installed on the inner side of the upper shaft 5, and a fall protection net 20 is installed inside the annular mounting frame 19.

[0033] In this embodiment, during installation, the annular mounting frame 19 provides a stable mounting carrier for the fall arrest net 20, ensuring that the fall arrest net 20 can be fixedly installed inside the upper shaft 5. When in use, the fall arrest net 20 can effectively block pedestrians, vehicles or other objects from accidentally falling into the shaft 2, thus avoiding safety accidents such as personal injury and property damage.

[0034] Example 9, as Figure 2 As shown, this embodiment adds the following structure based on embodiment 1: the top of the lower shaft 3 is provided with a docking groove 21, the bottom of the upper shaft 5 is provided with a docking protrusion 22 that matches the docking groove 21, the lower side of the connecting shaft 4 is provided with a connecting protrusion 23 that matches the docking groove 21, and the top of the connecting shaft 4 is provided with a connecting groove 24 that matches the docking protrusion 22.

[0035] In this embodiment, during the assembly of each well casing component, the combined use of the docking groove 21, docking protrusion 22, connecting protrusion 23 and connecting groove 24 can further enhance the positioning and connection installation effect of the lower well casing 3, connecting well casing 4 and upper well casing 5, resulting in high coaxiality between each well casing component and avoiding misalignment.

[0036] A manufacturing process for inspection wells with an inner surface coated with epoxy resin, characterized by the following steps: S1: Prefabrication of the well body. The steel reinforcement skeleton of the well body (including the reinforcement of the well cover, the reinforcement of the well seat, the reinforcement of the pipe interface and the reinforcement of the positioning hole) is tied according to the design dimensions. The steel reinforcement skeleton is placed into a customized cylindrical mold. Ordinary Portland cement, crushed stone, sand and water are mixed in the mass ratio to prepare concrete. The concrete is poured into the mold, vibrated to compact it, and then cured. After curing, the mold is removed to obtain the prefabricated well body. S2: Surface pretreatment, grinding the inner wall of the precast well body to remove surface laitance, burrs and impurities. After grinding, the surface is rinsed with a high-pressure water gun and then dried with compressed air to ensure surface dryness. S3: Preparation of epoxy resin coating Preparation of inner transition coating: Epoxy resin, silane coupling agent and diluent are mixed in mass ratio and stirred evenly to obtain inner transition coating. The inner transition coating is evenly coated on the pretreated well body wall using a high-pressure airless sprayer. After coating, it is allowed to stand and cure to form inner transition coating. Preparation of intermediate anti-corrosion coating: Epoxy resin, glass fiber, curing agent and toughening agent are mixed in mass ratio and stirred evenly to obtain intermediate anti-corrosion coating. The intermediate anti-corrosion coating is evenly applied to the inner transition coating surface by scraping. During the scraping process, it is ensured that the coating is evenly filled and there are no bubbles or missed coating. After coating, it is allowed to stand and cure to form intermediate anti-corrosion coating. Preparation of surface wear-resistant coating: Epoxy resin, alumina powder, curing agent and diluent are mixed in mass ratio and stirred evenly to obtain surface wear-resistant coating; the surface wear-resistant coating is evenly coated on the surface of intermediate anti-corrosion coating by roller coating, and then allowed to stand for curing to form surface wear-resistant coating. S4: Manhole cover installation. Place the manhole cover over the upper manhole casing to complete the overall production and assembly of the inspection manhole.

[0037] In this embodiment, the reinforcing steel skeleton of the well body, including the well cover steel, well seat steel, pipe interface steel, and positioning hole steel, is tied according to the design dimensions. The reinforcing steel skeleton is placed in a customized cylindrical mold. Concrete is prepared using ordinary Portland cement, crushed stone, sand, and water in a mass ratio of 1:3:2.5:0.5. The concrete is poured into the mold, vibrated to compact it, and then cured. The curing temperature is 20-25℃, the curing humidity is not less than 90%, and the curing time is 28 days. After curing, the mold is removed to obtain the precast well body. The surface of the precast well body is pretreated, and the inner wall of the precast well body is... Grinding is performed to remove surface laitance, burrs, and impurities. After grinding, the surface is rinsed with a high-pressure water gun at a pressure of 3–5 MPa, and then dried with compressed air at a pressure of 0.6–0.8 MPa, ensuring that the surface moisture content is no more than 6%. Preparation of the inner transition coating: Epoxy resin, silane coupling agent, and diluent are mixed according to the mass ratio and stirred evenly at a speed of 300–500 r / min for 15–20 min to obtain the inner transition coating. The inner transition coating is then sprayed using a high-pressure airless sprayer at a pressure of 15–20 MPa. The coating is uniformly applied to the pretreated wellbore wall. After coating, it is allowed to cure at 25-30℃ for 12-16 hours to form an inner transition coating. The intermediate anti-corrosion coating is prepared by mixing epoxy resin, glass fiber, curing agent, and toughening agent according to the mass ratio, stirring at a speed of 400-600 r / min for 20-25 minutes to obtain the intermediate anti-corrosion coating. This intermediate anti-corrosion coating is then uniformly applied to the surface of the inner transition coating using a scraping method. During the scraping process, it is ensured that the coating fills evenly, without bubbles or missed areas. After coating, it is allowed to cure at 30-35℃. After standing and curing for 24–30 hours, an intermediate anti-corrosion coating is formed. The surface wear-resistant coating is prepared by mixing epoxy resin, alumina powder, curing agent, and diluent according to a mass ratio, stirring at a speed of 300–500 r / min for 15–20 minutes to obtain a surface wear-resistant coating. The surface wear-resistant coating is then uniformly applied to the surface of the intermediate anti-corrosion coating using a roller coating method. After application, it is left to stand and cure for 18–22 hours at 25–30℃ to form the surface wear-resistant coating. The well cover is then placed on top of the upper well casing, completing the overall production and assembly of the inspection well.

[0038] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A manhole with an inner surface coated with epoxy resin, comprising a manhole base (1), characterized in that: The well body (2) is installed on the top of the well base (1). The well body (2) includes a lower well cylinder (3), a connecting well cylinder (4) and an upper well cylinder (5) installed sequentially from bottom to top. The lower well cylinder (3) and the well base (1) are integrally cast and molded. Several pipe interfaces (6) are evenly arranged along the circumferential direction on the lower side wall of the lower well cylinder (3). A connecting pipe (7) is installed in the pipe interface (6). The connecting well cylinder (4) is installed on the top of the lower well cylinder (3). The upper well cylinder (5) is installed on the top of the connecting well cylinder (4). A well cover (8) is installed on the top of the upper well cylinder (5). An epoxy resin coating (9) is provided on the inner side of the well body (2). The epoxy resin coating (9) includes an inner transition coating (10). An intermediate anti-corrosion coating (11) is coated on the outer side of the inner transition coating (10). A surface wear-resistant coating (12) is coated on the outer side of the intermediate anti-corrosion coating (11).

2. The inspection well with its inner surface coated with epoxy resin according to claim 1, characterized in that: The pipe interface (6) and the lower shaft (3) are integrally cast and molded structures, and the inner side of the pipe interface (6) is flush with the inner wall of the lower shaft (3).

3. A manhole with an inner surface coated with epoxy resin according to claim 2, characterized in that: The axis of the connecting pipe (7) is perpendicular to the axis of the lower shaft (3), and the inner diameter of the connecting pipe (7) matches the outer diameter of the urban pipeline to be connected.

4. A manhole with an inner surface coated with epoxy resin according to claim 3, characterized in that: The inner transition coating (10) is made of a mixed coating of epoxy resin and silane coupling agent, the intermediate anti-corrosion coating (11) is made of a composite coating of epoxy resin and glass fiber, and the surface wear-resistant coating (12) is made of a mixed coating of epoxy resin and alumina powder.

5. A manhole with an inner surface coated with epoxy resin according to claim 4, characterized in that: The bottom of the well base (1) is equipped with several fixed piles (13), and the surface of the fixed piles (13) is provided with several barbs (14).

6. A manhole with an inner surface coated with epoxy resin according to claim 5, characterized in that: The well base (1) is equipped with positioning rods (15) on all four sides of its surface. The lower well barrel (3), the connecting well barrel (4) and the upper well barrel (5) are provided with positioning holes (16) that match the positioning rods (15).

7. A manhole with an inner surface coated with epoxy resin according to claim 6, characterized in that: The top of the upper shaft (5) is provided with an annular assembly groove (17), and an assembly seat (18) is installed in the annular assembly groove (17). The top of the assembly seat (18) is fixedly installed on the bottom of the well cover (8).

8. A manhole with an inner surface coated with epoxy resin according to claim 7, characterized in that: An annular mounting frame (19) is installed on the inner side of the upper shaft (5), and a fall protection net (20) is installed inside the annular mounting frame (19).

9. A manhole with an inner surface coated with epoxy resin according to claim 8, characterized in that: The lower shaft (3) has a docking groove (21) at the top, the upper shaft (5) has a docking protrusion (22) at the bottom that matches the docking groove (21), the connecting shaft (4) has a connecting protrusion (23) at the bottom that matches the docking groove (21), and the connecting shaft (4) has a connecting groove (24) at the top that matches the docking protrusion (22).

10. A manufacturing process for a manhole with an inner surface coated with epoxy resin as described in any one of claims 1 to 9, characterized in that: Includes the following steps: S1: Prefabrication of the well body. The steel reinforcement skeleton of the well body (including the reinforcement of the well cover, the reinforcement of the well seat, the reinforcement of the pipe interface and the reinforcement of the positioning hole) is tied according to the design dimensions. The steel reinforcement skeleton is placed into a customized cylindrical mold. Ordinary Portland cement, crushed stone, sand and water are mixed in the mass ratio to prepare concrete. The concrete is poured into the mold, vibrated to compact it, and then cured. After curing, the mold is removed to obtain the prefabricated well body. S2: Surface pretreatment, grinding the inner wall of the precast well body to remove surface laitance, burrs and impurities. After grinding, the surface is rinsed with a high-pressure water gun and then dried with compressed air to ensure surface dryness. S3: Preparation of epoxy resin coating Preparation of inner transition coating: Epoxy resin, silane coupling agent and diluent are mixed in mass ratio and stirred evenly to obtain inner transition coating. The inner transition coating is evenly coated on the pretreated well body wall using a high-pressure airless sprayer. After coating, it is allowed to stand and cure to form inner transition coating. Preparation of intermediate anti-corrosion coating: Epoxy resin, glass fiber, curing agent and toughening agent are mixed in mass ratio and stirred evenly to obtain intermediate anti-corrosion coating. The intermediate anti-corrosion coating is evenly applied to the inner transition coating surface by scraping. During the scraping process, it is ensured that the coating is evenly filled and there are no bubbles or missed coating. After coating, it is allowed to stand and cure to form intermediate anti-corrosion coating. Preparation of surface wear-resistant coating: Epoxy resin, alumina powder, curing agent and diluent are mixed in mass ratio and stirred evenly to obtain surface wear-resistant coating; the surface wear-resistant coating is evenly coated on the surface of intermediate anti-corrosion coating by roller coating, and then allowed to stand for curing to form surface wear-resistant coating. S4: Manhole cover installation. Place the manhole cover over the upper manhole casing to complete the overall production and assembly of the inspection manhole.

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