Stainless steel and carbon steel composite pipe, expansion ring composite system and process

Abstract

The application discloses a stainless steel and carbon steel composite pipe, which comprises a stainless steel pipe coaxially arranged at an outer layer and a carbon steel pipe at an inner layer, and the stainless steel pipe and the carbon steel pipe are filled and bonded through PE. The application also provides a ring expansion composite system and process, a stainless steel and carbon steel composite pipe, a clamping mechanism symmetrically arranged at two ends of the stainless steel pipe and the carbon steel pipe, a PE supply device for pressing flowy PE into an annular cavity between the stainless steel pipe and the carbon steel pipe through the clamping mechanism, and a heating and heat preserving device for heating and heat preserving the carbon steel pipe. The stainless steel and carbon steel composite pipe has the advantages that the outer layer of stainless steel is used for resisting oxidation and corrosion, the inner layer of carbon steel is used for resisting water pressure, the strength of the composite pipe is ensured, the PE at the middle part is used for bonding the stainless steel layer and the carbon steel layer into a whole, the overall strength of the composite pipe is improved, and the manufacturing difficulty of the composite pipe is reduced.

Description

A stainless steel and carbon steel composite pipe, an expansion ring composite system and process Technical Field

[0001] This invention relates to the field of water supply and drainage steel pipes and their manufacturing technology, and particularly to composite steel pipes and their manufacturing systems and manufacturing processes. Specifically, it relates to a stainless steel and carbon steel composite pipe, an expansion ring composite system and process. Background Technology

[0002] Pipes are indispensable in water supply and drainage engineering. Existing pipes vary in material, diameter, and strength depending on their intended use and installation environment. For small- to medium-diameter pipes used in non-pressure applications, PVC pipes are generally used; for small- to medium-pressure applications, thickened PE pipes are typically used; and for large-diameter pressure applications, metal pipes are usually employed. Metal pipes are generally made of steel. Since steel pipes oxidize when in contact with water, rust forms, affecting water quality, increasing impurities in the water, and reducing pipe strength. To address this issue, pipe manufacturers have improved metal pipes by applying a rust-preventive layer to the inner wall through hot-melt embedding, self-adhesion, or spraying, thus protecting the metal pipe and preventing corrosion. However, large-diameter water supply pipes are installed underground, exposed, or overhead. Therefore, the outer wall of the pipe also needs rust prevention treatment to prevent the pipe structure and strength from being affected or damaged over time. Due to the large diameter and weight of the pipes, painting is usually done after installation to isolate the pipe wall from external contact, preventing oxidation and corrosion and extending service life. Paint itself will also oxidize, harden, peel, and flake off during long-term exposure to sunlight or rain, offering very limited protection. Therefore, this application provides a novel composite pipe to address the oxidation and corrosion resistance issues of large-diameter pipes, simultaneously meeting the requirements of high structural strength, strong corrosion resistance, and long service life. Summary of the Invention

[0003] To address the problem of large-diameter metal water supply pipes inevitably corroding during long-term use, thus reducing pipe strength and pressure resistance and affecting pipe lifespan, this application provides a stainless steel and carbon steel composite pipe, an expansion ring composite system, and a process for manufacturing a novel high-strength, long-life composite pipe to replace existing large-diameter metal pipes. Large-diameter metal pipes are most widely used in the main pipelines of water supply systems, typically employing large-diameter metal pipes. Although existing plastic pipes also have large-diameter versions with high structural strength, in water supply systems, large-diameter pipes need to withstand high pressure for extended periods. Leakage repairs are difficult, and since large-diameter water pipes are often buried underground, leaks or bursts can lead to widespread water outages, making repairs challenging and potentially causing localized ground subsidence or collapse. Considering these factors, large-diameter high-pressure water pipes are typically made of high-strength metal pipes. Existing buried large-diameter metal pipes, due to their large thickness, mostly use bare pipes or bare pipes with anti-rust layers or coatings. In the long-term humid underground environment, they will also be oxidized and corroded. In order to achieve the effect of long-term stable use after one installation, this invention provides a new composite pipe structure to replace the existing ordinary metal pipes. At the same time, this invention also provides a system and process for preparing composite pipes for manufacturing stainless steel and carbon steel composite pipes.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0005] A stainless steel and carbon steel composite pipe includes a stainless steel pipe coaxially arranged on the outer layer and a carbon steel pipe located on the inner layer, wherein the stainless steel pipe and the carbon steel pipe are bonded together by PE filler.

[0006] The present invention also provides an expansion ring composite system for the above-mentioned stainless steel and carbon steel composite pipe, including a clamping mechanism, which is symmetrically installed at both ends of the stainless steel pipe and the carbon steel pipe and fixes the stainless steel pipe and the carbon steel pipe coaxially.

[0007] A PE supply device is used to press flowing PE into the annular cavity between the stainless steel pipe and the carbon steel pipe through a clamping mechanism;

[0008] Heating and insulation device, used for heating and insulation of carbon steel pipes.

[0009] Preferably, the clamping mechanism includes a plurality of clamping claws arranged in a circular array for clamping the carbon steel pipe, each clamping claw being slidably disposed radially on the clamping seat, a dynamic expansion ring slidably disposed in the annular cavity, and a static sealing ring disposed between the stainless steel pipe and the carbon steel pipe near the end for sealing the annular cavity, wherein at least one guide pipe is provided through the static sealing ring for connecting the annular cavity and the PE supply device.

[0010] Preferably, the clamping mechanism includes a plurality of clamping claws arranged in a circular array for clamping the stainless steel pipe, each clamping claw being radially slidably disposed on the clamping seat, a dynamic expansion ring slidably disposed within the annular cavity, and a static sealing ring disposed between the stainless steel pipe and the carbon steel pipe near the end for sealing the annular cavity, the static sealing ring having at least one guide pipe passing through it for connecting the annular cavity and the PE supply device; it also includes a central base disposed along the central axis of the clamping seat, the central base having a mounting plate detachably and fixedly connected to one end near the carbon steel pipe for fixing and supporting the carbon steel pipe.

[0011] Preferably, the mounting plate includes a metal plate body, the metal plate body having a circumferential conical surface, and a high-temperature resistant sealing layer is bonded to the circumferential conical surface.

[0012] Preferably, the high-temperature resistant sealing layer is carbon fiber filled PTFE.

[0013] Preferably, the heating and heat preservation device includes a tank for holding a fluid medium, a heating unit for heating the fluid, a pump for driving the fluid to circulate between the carbon steel pipe and the tank, a temperature sensor and a liquid level sensor installed in the tank for collecting the fluid temperature, and a control unit electrically connected to the temperature sensor, the liquid level sensor, the heating unit and the pump.

[0014] The present invention also provides an expanding ring composite process, which is based on the expanding ring composite system provided above and is implemented through the following steps:

[0015] S100 material cleaning is used to clean the inner and outer surfaces of stainless steel and carbon steel pipes that need to be processed.

[0016] S200 sealing installation: The clamping mechanism is sealed and fixed at both ends of the stainless steel pipe and the carbon steel pipe.

[0017] S300 heating and heat preservation: turn on the heating and heat preservation device to heat the fluid and circulate it in the carbon steel pipe to heat the carbon steel pipe until the temperature reaches the preset temperature value T = 80℃-110℃.

[0018] S400 hot melt bonding: Turn on the PE supply device to press the PE heated to a molten state into the annular cavity until the dynamic expansion ring slides to the end of the annular cavity away from the end into which the flowing PE enters;

[0019] After S500 cooling and molding, the expansion ring composite system is turned off and the composite tube is cooled to room temperature before being removed and allowed to set naturally.

[0020] Beneficial effects:

[0021] 1. The stainless steel-carbon steel composite pipe provided by the present invention has an outer layer of stainless steel for anti-oxidation and corrosion, an inner layer of carbon steel for resisting water pressure and ensuring the strength of the composite pipe, and a PE layer in the middle for bonding the stainless steel layer and the carbon steel layer together, thereby improving the overall strength of the composite pipe and reducing the manufacturing difficulty of using direct metal sleeves for the composite pipe.

[0022] 2. The expansion ring filling PE structure provided by the present invention can effectively avoid air bubbles during the PE filling process, and avoid voids between stainless steel pipe and carbon steel pipe, thereby reducing the deformation resistance of the stainless steel outer layer.

[0023] 3. The expansion ring composite process provided by the present invention can quickly bond stainless steel pipe and carbon steel pipe together to form an integrated structure. The resulting composite pipe has the advantages of high strength, strong pressure resistance, good corrosion and oxidation resistance, and long service life. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 is a schematic diagram of an embodiment of the clamping mechanism of the present invention connected to the composite pipe.

[0026] Figure 2 is the right view of Figure 1.

[0027] Figure 3 is a full sectional view along the section symbol AA in Figure 2.

[0028] Figure 4 is a schematic diagram of another embodiment of the clamping mechanism of the present invention connected to the composite pipe.

[0029] Figure 5 is the right view of Figure 4.

[0030] Figure 6 is a full sectional view along the section symbol BB in Figure 5.

[0031] Figure 7 is a schematic diagram of the composite system.

[0032] In the figure: 1-clamping mechanism; 2-central base; 3-mounting plate; 4-circumferential conical surface; 5-static sealing ring; 6-guide pipe; 7-dynamic expansion ring; 8-stainless steel pipe; 9-carbon steel pipe; 10-annular cavity. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this application, it should be noted that the use of terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product is in use. These terms are used solely for the convenience of describing this application 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 this application. Furthermore, the use of terms such as "first" and "second" in the description of this application is only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this application does not imply that the component is required to be absolutely horizontal or suspended, but rather that it may be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but rather that it may be slightly tilted.

[0038] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] Example 1:

[0040] As shown in Figure 3, a stainless steel and carbon steel composite pipe includes a stainless steel pipe 8 coaxially arranged on the outer layer and a carbon steel pipe 9 on the inner layer. The stainless steel pipe 8 and the carbon steel pipe 9 are bonded together with PE filler. The stainless steel and carbon steel composite pipe has extremely high compressive strength internally and excellent corrosion and oxidation resistance externally. The PE filler in the middle layer allows for rapid hot-melt bonding of the outer stainless steel pipe 8 and the inner carbon steel pipe 9, ensuring that the relatively thin stainless steel pipe 8 also possesses high resistance to external forces and excellent corrosion resistance. More importantly, the PE filler offers advantages such as fast speed, high efficiency, high strength, and good adhesion. The composite pipe structure provided in this embodiment is simple. Through gap nesting installation and fluid PE filling, the temperature environment during processing is greatly reduced, resulting in low manufacturing costs.

[0041] Example 2:

[0042] Referring to Figures 1-3 in the specification, this embodiment provides an expansion ring composite system for the aforementioned stainless steel and carbon steel composite pipe. It includes a clamping mechanism 1, symmetrically installed at both ends of a stainless steel pipe 8 and a carbon steel pipe 9, and coaxially fixing the stainless steel pipe 8 and carbon steel pipe 9. The clamping mechanism 1 includes multiple clamping claws arranged in a circular array for clamping the stainless steel pipe 8, each clamping claw slidingly on a clamping seat along the radial direction. It also includes a dynamic expansion ring 7 slidably disposed within the annular cavity 10 and a static sealing ring 5 disposed near the end between the stainless steel pipe 8 and the carbon steel pipe 9 for sealing the annular cavity 10. At least one guide pipe 6 is provided through the static sealing ring 5 for connecting the annular cavity 10 and a PE supply device. The system also includes a central base disposed along the central axis of the clamping seat. A mounting plate 3 for fixing and supporting the carbon steel pipe 9 is detachably and fixedly connected to one end of the central base near the carbon steel pipe 9. The mounting plate 3 includes a metal plate body with a circumferential conical surface 4, on which a high-temperature resistant sealing layer is adhered. The high-temperature resistant sealing layer is made of carbon fiber filled PTFE.

[0043] A PE supply device is used to press flowing PE into the annular cavity 10 between the stainless steel pipe 8 and the carbon steel pipe 9 through a clamping mechanism 1.

[0044] A heating and heat preservation device is used to heat and preserve the carbon steel pipe 9. The heating and heat preservation device includes a tank for holding a fluid medium, a heating unit for heating the fluid, a pump for driving the fluid to circulate between the carbon steel pipe 9 and the tank, a temperature sensor and a liquid level sensor installed in the tank for collecting the fluid temperature, and a control unit electrically connected to the temperature sensor, the liquid level sensor, the heating unit and the pump.

[0045] Working principle:

[0046] This embodiment is suitable for stainless steel pipe 8 with high strength, which can be used for clamping and fixing. If the thickness of stainless steel pipe 8 is small and it does not have strong resistance to deformation, then the fixing method of this embodiment is not suitable. In this embodiment, the clamping mechanism 1 plays a fixing role by clamping claws installed on the clamping seat. By adjusting the radial position of the clamping claws, stainless steel pipes 8 with different outer diameters can be clamped and fixed. The structure can adopt the existing three-jaw chuck structure or a similar structure. Of course, the number of clamping claws can be more than three, with the aim of stably clamping the stainless steel pipe 8. The clamping method is shown in Figure 1. Then, the dynamic expansion ring 7 and the static sealing ring 5 are sleeved on the carbon steel pipe 9, and the two ends of the carbon steel pipe 9 are respectively fixed on the mounting plate 3 to form a sealing structure. At this time, the dynamic expansion ring 7 and the static sealing ring 5 are both located at the ends of the stainless steel pipe 8 and the carbon steel pipe 9, and it should be ensured that the static sealing ring 5 abuts against the clamping claws or the clamping seat to avoid the PE supply device being washed away and causing PE leakage when injecting flowing PE into the annular cavity 10. After installation, molten PE is injected into the annular cavity 10 via a PE supply device. As the PE enters, it pushes the dynamic expansion ring 7 along the axis of the carbon steel pipe 9. Since the dynamic expansion ring 7 has a flexible structure that forms a contact seal with the inner wall of the stainless steel 8 and the outer wall of the carbon steel pipe 9 but does not have significant pressure resistance, the internal air bubbles can be naturally expelled under the push of the PE. As the PE continues to be injected, and given the high viscosity of the fluid PE, it cannot flow freely through the dynamic expansion ring 7, but instead pushes the dynamic expansion ring 7 to move until it reaches the other end of the carbon steel pipe 9. At this point, the entire annular cavity 10 is filled with PE, and after cooling, an integrated composite pipe structure is formed. In this embodiment, the dynamic expansion ring 7 is a key structure that ensures the high-viscosity PE can fill the annular cavity 10 segment by segment. It is the key point of this invention. Without the dynamic expansion ring 7, the stainless steel pipe 8 and carbon steel pipe 9 would need to be kept vertical, which would cause great manufacturing difficulties. The length of the large-diameter steel pipes ranges from tens of meters to hundreds of meters, and vertical filling is not feasible. At the same time, vertical PE injection would also result in extremely high liquid pressure at the bottom of the pipe, which would be a great challenge to the sealing structure. However, with the structure of this embodiment, there is almost no significant fluid pressure problem.

[0047] Example 3:

[0048] Referring to Figures 4-6 in the specification, this embodiment provides an expansion ring composite system for the aforementioned stainless steel and carbon steel composite pipe. It includes a clamping mechanism 1, symmetrically installed at both ends of the stainless steel pipe 8 and the carbon steel pipe 9, and coaxially fixing the stainless steel pipe 8 and the carbon steel pipe 9. The clamping mechanism 1 includes multiple clamping claws arranged in a circular array for clamping the carbon steel pipe 9, each clamping claw sliding radially on a clamping seat. It also includes a dynamic expansion ring 7 slidably disposed within the annular cavity 10 and a static sealing ring 5 disposed near the end of the stainless steel pipe 8 and the carbon steel pipe 9 for sealing the annular cavity 10. At least one guide pipe 6 is provided through the static sealing ring 5 for connecting the annular cavity 10 and a PE supply device.

[0049] A PE supply device is used to press flowing PE into the annular cavity 10 between the stainless steel pipe 8 and the carbon steel pipe 9 through a clamping mechanism 1.

[0050] A heating and insulation device is used to heat and insulate the carbon steel pipe 9. The device includes a tank for holding the fluid medium, a heating unit for heating the fluid, a pump for driving the fluid to circulate between the carbon steel pipe 9 and the tank, a temperature sensor and a level sensor installed inside the tank for collecting fluid temperature, and a control unit electrically connected to the temperature sensor, level sensor, heating unit, and pump. The principle of this embodiment is basically the same as that of Embodiment 2, only the fixing method is different. The biggest difference between this embodiment and Embodiment 2 is that it is applied to situations where the stainless steel pipe 8 is thin and does not have strong resistance to deformation. In this case, the stainless steel pipe 8 mainly serves to wrap and resist corrosion, and does not bear large external forces alone, as shown in Figure 4. The working principle of other parts is basically the same as that of Embodiment 2, and will not be described in detail here.

[0051] Example 4:

[0052] This embodiment provides an expanding ring composite process, which is implemented based on the expanding ring composite system provided above, and is achieved through the following steps:

[0053] S100 material cleaning involves cleaning the inner and outer surfaces of the stainless steel pipe 8 and carbon steel pipe 9 that need to be processed.

[0054] S200 sealing installation: The clamping mechanism 1 is sealed and fixed at both ends of the stainless steel pipe 8 and the carbon steel pipe 9.

[0055] The S300 heating and insulation device heats the fluid and circulates it through the carbon steel pipe 9 until the temperature reaches the preset value T = 80℃-110℃. In this embodiment, the temperature only needs to be around 100℃. Compared to the processing of other metal pipes, which often involves temperatures exceeding 1000℃, this embodiment provides a low-temperature operation, which greatly saves energy and reduces the safety hazards of high-temperature operations. Since molten PE can maintain a stable fluid state even at around 100℃ and will not solidify rapidly, it ensures that the PE can stably push the expansion ring 7 along the carbon steel pipe 9 to the other end, without the problem of increased viscosity and inability to flow due to temperature reduction. In other words, in this process, the temperature only needs to ensure normal PE flow; no additional heating of the PE is required. This allows the heating and insulation device to complete the process simply by heating and circulating water, resulting in extremely low insulation costs and broad application prospects.

[0056] S400 hot melt bonding: turn on the PE supply device to press the PE heated to a molten state into the annular cavity 10 until the dynamic expansion ring 7 slides to the end of the annular cavity 10 away from the end into which the flowing PE enters.

[0057] After S500 cooling and molding, the expansion ring composite system is turned off and the composite tube is cooled to room temperature before being removed and allowed to set naturally.

[0058] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An expansion ring composite system for manufacturing a stainless steel and carbon steel composite pipe, characterized in that: The composite pipe includes a stainless steel pipe (8) coaxially arranged on the outer layer and a carbon steel pipe (9) on the inner layer, wherein the stainless steel pipe (8) and the carbon steel pipe (9) are bonded together by PE filling; it also includes a clamping mechanism (1) symmetrically installed at both ends of the stainless steel pipe (8) and the carbon steel pipe (9) and fixing the stainless steel pipe (8) and the carbon steel pipe (9) coaxially; and a PE supply device for pressing the flowing PE into the annular cavity (10) between the stainless steel pipe (8) and the carbon steel pipe (9) through the clamping mechanism (1); A heating and heat preservation device is used to heat and preserve the carbon steel pipe (9); the clamping mechanism (1) includes a plurality of clamping claws arranged in a circular array for clamping the carbon steel pipe (9), each clamping claw being slidably disposed on the clamping seat in the radial direction, as well as a dynamic expansion ring (7) slidably disposed in the annular cavity (10) and a static sealing ring (5) disposed between the stainless steel pipe (8) and the carbon steel pipe (9) near the end for sealing the annular cavity (10), and at least one guide pipe (6) is provided through the static sealing ring (5) for connecting the annular cavity (10) and the PE supply device.

2. The expanding ring composite system according to claim 1, characterized in that: The clamping mechanism (1) includes a plurality of clamping claws arranged in a circular array for clamping the stainless steel pipe (8), each clamping claw being slidably disposed on the clamping seat in the radial direction, as well as a dynamic expansion ring (7) slidably disposed in the annular cavity (10) and a static sealing ring (5) disposed near the end between the stainless steel pipe (8) and the carbon steel pipe (9) for sealing the annular cavity (10), and at least one guide pipe (6) for connecting the annular cavity (10) and the PE supply device is provided through the static sealing ring (5); it also includes a central base disposed along the central axis of the clamping seat, and a mounting plate (3) for fixing and supporting the carbon steel pipe (9) is detachably and fixedly connected to one end of the central base near the carbon steel pipe (9).

3. The expanding ring composite system according to claim 2, characterized in that: The mounting plate (3) includes a metal plate body, the metal plate body has a circumferential conical surface (4), and a high-temperature resistant sealing layer is bonded to the circumferential conical surface (4).

4. The expanding ring composite system according to claim 3, characterized in that: The high-temperature resistant sealing layer is made of carbon fiber filled PTFE.

5. The expanding ring composite system according to claim 1, characterized in that: The heating and heat preservation device includes a box for holding fluid medium, a heating unit for heating the fluid, a pump for driving the fluid to circulate between the carbon steel pipe (9) and the box, a temperature sensor and a liquid level sensor installed in the box for collecting fluid temperature, and a control unit electrically connected to the temperature sensor, the liquid level sensor, the heating unit and the pump.

6. An expanding ring composite process, implemented based on the expanding ring composite system according to any one of claims 1-5, characterized in that: The process is achieved through the following steps: S100 Material cleaning: Clean the inner and outer surfaces of the stainless steel pipe (8) and carbon steel pipe (9) to be processed; S200 Sealing installation: Seal and install the clamping mechanism (1) at both ends of the stainless steel pipe (8) and carbon steel pipe (9) and fix it; S300 Heating and heat preservation: Turn on the heating and heat preservation device to heat the fluid and circulate it in the carbon steel pipe (9) to heat the carbon steel pipe (9) until the temperature reaches the preset temperature value T=80℃-110℃; S400 Hot melt bonding: Turn on the PE supply device to press the PE heated to the molten state into the annular cavity (10) until the dynamic expansion ring (7) slides to the end of the annular cavity (10) away from the end into which the flowing PE enters; S500 Cooling and molding: Turn off the expansion ring composite system and cool to room temperature before removing the composite pipe and allowing it to set naturally.

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