Preparation method of high-temperature-resistant prefabricated thermal insulation pipeline

Abstract

The invention relates to a preparation method of a high-temperature-resistant prefabricated heat-preservation pipeline, which belongs to the heat-preservation pipeline preparation technology, and comprises the steps of inner steel pipe preparation, composite layer preparation, part preparation and part assembly: taking a seamless steel pipe as an inner steel pipe foundation, welding a central fixing ring at the central position of the inner steel pipe, and then cleaning the surface of the inner steel pipe; the composite layer is arranged on the outer wall of the inner steel pipe to remove oil stains, rust and dust impurities, then the inner steel pipe is subjected to anti-corrosion treatment, specifically, the inner steel pipe can be coated with anti-corrosion paint or subjected to hot galvanizing treatment, and the composite layer is composed of a heat preservation steel pipe arranged on the outer wall of the inner steel pipe, an anti-tearing layer wrapping the heat preservation steel pipe and an outer protection layer wrapping the anti-tearing layer. According to the pipeline leakage alarm device, the heat preservation effect is good, the intelligent degree is high, an alarm can be given in time when leakage occurs, rapid assembly between pipelines is facilitated, and high application value is achieved.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation pipe manufacturing technology, and in particular to a method for manufacturing a high-temperature resistant pre-insulated pipe. Background Technology

[0002] Insulated pipes are a type of piping material used for transporting liquids, gases, and other media. They possess excellent thermal insulation properties and are widely used in various fields such as petroleum, chemical, aerospace, and power systems. Insulated pipes mainly consist of a working steel pipe, an insulation layer, a protective shell, and a leak alarm line. The insulation layer typically uses rigid polyurethane foam or aerogel felt, providing good thermal insulation. The protective shell is made of high-density polyethylene or fiberglass to enhance the pipe's mechanical strength and corrosion resistance. However, leaks in existing insulated pipe systems are difficult to detect or pinpoint in a timely manner, potentially leading to significant accidents.

[0003] To address the aforementioned issues, Chinese invention patent CN106641592A discloses an intelligent insulated pipe with an alarm device. This pipe comprises an insulated pipe consisting of a steel pipe, an insulation layer, and an outer protective pipe. It also includes a test line, an alarm line, a lead-out connector, a lead-out wire, and a detection device. The test line and alarm line are embedded in the insulation layer, parallel to the axis of the steel pipe and maintaining a predetermined distance from the outer surface of the steel pipe. The lead-out connector is fixed at a pre-set monitoring point on the outer protective pipe of the insulated pipe. Two insulated leads are provided on the lead-out connector, one connected to the steel pipe and the other to the test line or alarm line, respectively. The lead-out wire connects the lead-out connector and the detection device. One end of the lead-out wire has a plug matching the lead-out connector, and the other end has a connector matching the detection device. This invention provides a reasonably structured and easy-to-operate intelligent insulated pipe with an alarm device. It can quickly detect leaks in the insulated pipe, facilitating timely repairs and preventing insulation layer erosion and carbonization caused by leaks of high-temperature media in the pipe.

[0004] However, its leakage detection function relies on a large number of electrical components and on the capacitance change caused by the medium entering the insulation layer for detection. This means that some gaseous media or media that have little impact on the insulation layer may not have a significant capacitance change, thus affecting the detection effect. Therefore, this application is made. Summary of the Invention

[0005] To overcome the technical defects of the existing technology, the present invention provides a method for preparing high-temperature resistant prefabricated insulated pipes, which has the advantages of good insulation effect, high degree of intelligence, and easy rapid assembly between pipes.

[0006] The technical solution adopted in this invention is: a method for preparing a high-temperature resistant pre-insulated pipe, comprising the following steps:

[0007] S1. Inner steel pipe preparation: a seamless steel pipe is used as the base of the inner steel pipe. A central fixing ring is welded at the center of the inner steel pipe. Then, the surface of the inner steel pipe is cleaned to remove oil, rust and dust impurities. Then, the inner steel pipe is treated with anti-corrosion coating or hot-dip galvanizing.

[0008] S2. Composite layer preparation: The composite layer consists of an insulated steel pipe for mounting on the outer wall of the inner steel pipe, a tear-resistant layer wrapped around the insulated steel pipe, and an outer protective layer wrapped around the tear-resistant layer. Seamless steel pipe is used as the insulated steel pipe surrounding the inner steel pipe. A composite fabric woven from cotton fiber and rubber filaments is used as the insulation material to prepare the tear-resistant layer. The cotton fiber provides insulation, while the highly elastic rubber filaments produce a loud sound when torn and rebound to a certain extent, which frightens wild animals from damaging the insulated pipe and prevents further damage. The composite fabric is tightly wrapped around the surface of the insulated steel pipe and fixed with wire mesh, so that the outer surface of the insulated steel pipe is fully covered with the composite fabric to form an insulated tear-resistant layer. Finally, an outer protective layer is wrapped around the outside of the tear-resistant layer.

[0009] S3. Component preparation: The components include an elastic telescopic plug rod for installation on the inner steel pipe, a gas density meter, a signal transmitter, a pipe wall detector, and a traction assembly for controlling the movement of the pipe wall detector. The pipe wall detector includes a sleeve ring and an ultrasonic detector fixedly installed on the inner wall of the sleeve ring. The sleeve ring is movably sleeved on the inner steel pipe. The outer wall of the sleeve ring has an external thread that connects to the threaded groove of the insulated steel pipe. It also includes a snap-fit ​​end and a mating end for connecting the two ends of the inner steel pipe, for realizing manual splicing and installation without drive or screws.

[0010] S4. Component assembly: Drill a number of holes in a uniform circular array on the central fixing ring, insert an elastic telescopic plug rod into each hole, and drill four mounting slots symmetrically on the two side walls of the central fixing ring, inserting a gas density meter and a signal transmitter into the slots.

[0011] Assemble and connect the pipe wall detection component and the traction assembly. The traction assembly is connected to both sides of each individual pipe wall detection component. Insertion grooves and threaded grooves are machined into the insulated steel pipe within the composite layer. The insertion grooves are used for inserting the elastic telescopic insertion rod. The composite layer and inner steel pipe are assembled and connected by inserting the elastic telescopic insertion rod into the insertion groove. Then, one side of the traction assembly is installed onto the side wall of the central fixing ring. Next, the pipe wall detection component is fitted onto the inner steel pipe and gradually screwed in using the threaded groove. The other side of the traction assembly is installed on the outer convex edge. Finally, the outer convex edge is welded to both ends of the inner steel pipe, connecting and sealing the inner steel pipe and the central fixing ring through the outer convex edge. Then, on the outer convex edge... An inflation valve is installed to fill the cavity between the inner steel pipe and the insulated steel pipe with inert gas. This, combined with a tear-resistant layer that provides insulation, forms a double insulation structure. The inert gas fills the cavity between the inner steel pipe and the composite layer, reducing thermal conductivity and improving insulation performance. It also makes the gas density inside the cavity different from that of ordinary air, which is used for leak detection by a gas density meter. The detection principle is as follows: after the inert gas is filled, the gas density meter reading is constant. When the inner steel pipe is partially cracked or damaged, the inert gas exchanges with the air in the inner steel pipe, causing the gas density meter reading to change. This change is then detected by an alarm signal transmitter.

[0012] S5. Overall assembly: Install snap-fit ​​ends and butt joint ends on both ends of the assembled inner steel pipe and composite layer, and add sealing gaskets at the connection to complete the preparation of the insulated pipe. The pipes can be connected by the cooperation of snap-fit ​​ends and butt joint ends.

[0013] When a pipeline leak occurs, the signal transmitter issues an alarm, and the traction component and ultrasonic detector are activated simultaneously. As the traction component moves the connecting ring, the ultrasonic detector detects the wall thickness of various parts of the inner steel pipe. After detecting the damage, it stops moving. At this time, the leak is temporarily sealed by the connecting ring to reduce material leakage in the insulated pipeline. The detection cycle of the ultrasonic detector can be set to one month or three months as needed to conduct regular pipeline inspections. A decrease or increase in the pipe wall thickness indicates that there may be an abnormality inside the pipeline.

[0014] Preferably, both the snap-fit ​​end and the mating end are composed of an integrally formed sealing cap and a mating ring. The sealing gasket is located inside the sealing cap, and the mating ring is located on the outer side of the sealing cap. In actual use, the sealing gasket is first placed inside the sealing cap, and then the sealing cap is put on the end of the assembled inner steel pipe and composite layer. The sealing gasket effectively seals the gap between the inner steel pipe and the composite layer to prevent air leakage.

[0015] Preferably, the docking ring at the docking end has several combined grooves arranged in a ring array. The combined grooves include circular through grooves and strip through grooves. The circular through groove has a larger diameter, which allows a larger diameter actuating rod to slide into the strip through groove and be locked in place.

[0016] Preferably, the mating ring of the snap-fit ​​end is provided with a plurality of elastic retractable rods arranged in a ring array. The telescopic end of the elastic retractable rod is connected to a lever. The elastic retractable rod is composed of an outer rod, an inner rod, and a highly elastic spring. The inner rod is slidably installed inside the outer rod through the spring, so that although the elastic retractable rod has a certain telescopic capacity, it has a strong retraction capacity when pulled out. That is, it can apply a strong pulling force to the snap-fit ​​end that is snapped by the lever, thereby ensuring that the snap-fit ​​end and the mating end can have a high connection strength after connection.

[0017] Preferably, the diameter of the actuating rod is smaller than the diameter of the circular through groove and larger than the width of the strip through groove. The diameter of the telescopic end of the elastic retractable rod is smaller than the width of the strip through groove, so that the actuating rod can pass through the circular through groove and then be engaged in the strip through groove. In actual use, a sealing ring is first placed between the snap-fit ​​end and the butt joint end of the two insulation pipes. Then the snap-fit ​​end and the butt joint end are joined together, so that the actuating rod passes through the circular through groove. Then the actuating rod is controlled to move into the strip through groove, so that the actuating rod is engaged in the strip through groove and will not come off.

[0018] Preferably, a flange is provided on one side of the combined groove, and the thickness of the flange gradually increases from the circular through groove to the strip through groove. A snap ring is fixedly provided on one side of the actuating rod, which can be snapped into the flange after the actuating rod moves to the end of the strip through groove. After the actuating rod slides from the circular through groove to the strip through groove, as the sliding distance increases, the actuating rod will be continuously pushed up by the flange to pull out the elastic telescopic rod. The spring applies a pull-back force, so that the snap-fit ​​end and the mating end can have a high connection strength after connection, so as to ensure the sealing effect of the sealing ring.

[0019] Preferably, the traction assembly includes a reel and a traction rope. The reel consists of a housing, a motor, and a reel connected to the output shaft of the motor. Both the motor and the reel are installed inside the housing. One end of the traction rope is fixed to the reel, and the other end is fixedly connected to the side wall of the sleeve ring. The sleeve ring is pulled by the reel. When the sleeve ring moves, it can rotate due to the setting of the threaded groove and internal thread, so as to carry the ultrasonic detector to perform pipe wall detection in multiple directions.

[0020] The beneficial effects of this invention are: 1. The insulated steel pipe and the inner steel pipe obtained by this invention have a cavity between them. In actual use, inert gas can be filled in, and a double insulation structure is formed with a tear-resistant layer with insulation capabilities. This effectively improves the insulation performance of the insulated pipe. The tear-resistant layer is made of cotton fiber, which has an insulation effect. The highly elastic rubber filaments can make a loud noise when torn and will rebound to a certain extent, thereby frightening wild animals when they damage the insulated pipe, thus preventing further damage to the insulated pipe.

[0021] 2. The thermal insulation pipe prepared by the present invention includes a snap-fit ​​end and a butt joint end. The connection between thermal insulation pipes is achieved by the cooperation of the snap-fit ​​end and the butt joint end, which enables installation without drive or screws. The splicing can be completed manually. Under the premise of ensuring the sealing effect, no other parts are needed, which greatly improves the installation efficiency.

[0022] 3. The insulated pipe prepared by this invention has an intelligent leak detection and emergency handling structure. When a pipe leak occurs, the signal transmitter issues an alarm, and the traction component and ultrasonic detector are also activated at the same time. During the process of the traction component moving the sleeve ring, the ultrasonic detector detects the wall thickness of each part of the inner steel pipe. After the damaged area is detected, the movement stops. At this time, the leak can be temporarily sealed by the sleeve ring to reduce the leakage of materials in the insulated pipe. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the cross-sectional structure of the insulated pipe prepared according to the present invention.

[0024] Figure 2 This is a schematic diagram of the overall structure of the insulated pipe.

[0025] Figure 3 This is a schematic diagram of the structure of the insulated pipe from the left side.

[0026] Figure 4 This is a schematic diagram of the connection end structure of an insulated pipe.

[0027] Figure 5 This is a schematic diagram of the clamping end structure of an insulated pipe.

[0028] Figure 6 for Figure 5 Enlarged view of a portion of point A in the middle.

[0029] Figure 7 This is a schematic diagram showing the connection between the docking end and the snap-fit ​​end.

[0030] Figure 8 This is a schematic diagram of the external structure of the inner steel pipe of an insulated pipeline.

[0031] Figure 9This is a schematic diagram of the pipe wall detection component and the traction assembly.

[0032] Figure 10 This is a schematic diagram of the internal structure of an insulated steel pipe.

[0033] Explanation of reference numerals in the attached figures: 1. Inner steel pipe; 101. Outer convex edge; 102. Central fixing ring; 103. Elastic telescopic plug-in rod; 104. Gas density meter; 105. Signal transmitter; 2. Insulated steel pipe; 201. Plug-in groove; 202. Threaded groove; 3. Tear-resistant layer; 4. Outer protective layer; 5. Snap-fit ​​end; 501. Elastic retraction rod; 502. Actuating rod; 503. Snap-fit ​​ring; 6. Butt joint end; 601. Sealing cap; 602. Butt joint ring; 603. Sealing gasket; 604. Circular through groove; 605. Strip through groove; 606. Flange; 7. Pipe wall detection component; 701. Sleeve ring; 702. Ultrasonic detector; 703. External thread; 8. Traction assembly; 801. Winding reel; 802. Traction rope. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings:

[0035] like Figures 1-10 As shown, this embodiment provides a method for preparing a high-temperature resistant pre-insulated pipe, including the following steps:

[0036] S1. Preparation of inner steel pipe 1: A seamless steel pipe is used as the base of inner steel pipe 1. A central fixing ring 102 is welded at the center of inner steel pipe 1. Then, the surface of inner steel pipe 1 is cleaned to remove oil, rust and dust impurities, which facilitates subsequent processing and reduces the surface friction of inner steel pipe 1. This makes the resistance of the pipe wall detection element 7 installed on inner steel pipe 1 less when it moves. Then, the inner steel pipe 1 is subjected to anti-corrosion treatment, which can be coated with anti-corrosion paint or hot-dip galvanized to effectively improve the corrosion resistance of inner steel pipe 1 and thus improve the service life of the pipeline.

[0037] S2. Composite Layer Preparation: The composite layer consists of an insulated steel pipe 2 installed on the outer wall of the inner steel pipe 1, a tear-resistant layer 3 wrapped around the insulated steel pipe 2, and an outer protective layer 4 wrapped around the tear-resistant layer 3. A seamless steel pipe is used as the insulated steel pipe 2, fitted over the inner steel pipe 1. A composite fabric woven from cotton fibers and rubber filaments is used as the insulation material to prepare the tear-resistant layer 3. The composite fabric is tightly wrapped around the surface of the insulated steel pipe 2 and fixed with wire mesh, ensuring that the outer surface of the insulated steel pipe 2 is fully covered with the composite fabric, forming an insulated tear-resistant layer 3. Finally... An outer protective layer 4 is wrapped around the outside of the tear-resistant layer 3. There is a cavity between the insulated steel pipe 2 and the inner steel pipe 1. In actual use, inert gas can be filled in. Together with the tear-resistant layer 3 with heat preservation capabilities, a double heat preservation structure is formed, which effectively improves the heat preservation performance of the insulated pipe. The tear-resistant layer 3 is made of cotton fiber, which has a heat preservation effect. The highly elastic rubber filament can make a loud noise when torn and will rebound to a certain extent, so that wild animals will be frightened when they damage the insulated pipe, thus avoiding further damage to the insulated pipe.

[0038] S3. Component preparation: The components include an elastic telescopic plug rod 103 for installation on the inner steel pipe 1, a gas density meter 104, a signal transmitter 105, a pipe wall detector 7, and a traction assembly 8 for controlling the movement of the pipe wall detector 7. It also includes a snap-fit ​​end 5 and a butt joint end 6 for connecting the two ends of the inner steel pipe 1. The various insulated pipes can be installed without drive or screws through the cooperation of the snap-fit ​​end 5 and the butt joint end 6. Under the premise of ensuring the sealing effect, no other components are needed, which greatly improves the installation efficiency.

[0039] S4. Component assembly: Drill a number of holes in a uniform circular array on the central fixing ring 102, insert an elastic telescopic plug rod 103 into each hole, drill four mounting slots symmetrically on the two side walls of the central fixing ring 102, and install a gas density meter 104 and a signal transmitter 105 into the slots.

[0040] Assemble and connect the pipe wall detection component 7 and the traction assembly 8. The traction assembly 8 is connected to both sides of each individual pipe wall detection component 7. A insertion groove 201 and a threaded groove 202 are machined into the insulated steel pipe 2 within the composite layer. The insertion groove 201 is used for the insertion of the elastic telescopic insertion rod 103. The composite layer and the inner steel pipe 1 are assembled and connected by inserting the elastic telescopic insertion rod 103 into the insertion groove 201. Then, one side of the traction assembly 8 is installed onto the side wall of the central fixing ring 102. The pipe wall detection component 7 is then fitted onto the inner steel pipe 1 and gradually screwed into the interior using the threaded groove 202. The other side of the traction assembly 8 is installed on the outer protrusion 101. Finally, the outer protrusion 101 is welded to both ends of the inner steel pipe 1, connecting and sealing the inner steel pipe 1 and the central fixing ring 102 through the outer protrusion 101. An inflation valve is then installed on the outer protrusion 101 to inflate the inner steel pipe. Inert gas is filled into the cavity between pipe 1 and insulated steel pipe 2. The purpose of filling inert gas is twofold: firstly, it fills the cavity between the inner steel pipe 1 and the composite layer, reducing thermal conductivity and improving insulation performance; secondly, it makes the gas environment density in the cavity different from that of ordinary air, which is beneficial for leak detection by gas density meter 104. The specific detection principle is as follows: after filling inert gas, the detection value of gas density meter 104 remains constant. When the inner steel pipe 1 has a local crack or damage, the inert gas exchanges with the air in the inner steel pipe 1. At this time, the value detected by gas density meter 104 will change, and then an alarm signal can be sent through signal transmitter 105. Compared with existing insulated pipes with intelligent alarms, this application uses fewer electrical components, has lower cost, and higher application value.

[0041] S5. Overall assembly: Install snap-fit ​​ends 5 and butt joint ends 6 at both ends of the assembled inner steel pipe 1 and composite layer, and add sealing gaskets 603 at the connection to complete the preparation of the insulated pipe. The pipes can be connected by the cooperation of snap-fit ​​ends 5 and butt joint ends 6.

[0042] Both the snap-fit ​​end 5 and the mating end 6 are composed of an integrally formed sealing cap 601 and mating ring 602. The sealing gasket 603 is located inside the sealing cap 601, and the mating ring 602 is located on the outer side of the sealing cap 601. In actual use, the sealing gasket 603 is first placed inside the sealing cap 601, and then the sealing cap 601 is fitted onto the assembled inner steel pipe 1 and the end of the composite layer. The sealing gasket 603 effectively seals the gap between the inner steel pipe 1 and the composite layer to prevent air leakage. The mating ring 602 of the mating end 6 has several combined grooves arranged in a ring array. The combined grooves include a circular through groove 604 and a strip through groove 605. The circular through groove 604 has a larger diameter, which allows the larger diameter actuating rod 502 to pass through. The actuating rod 502 can be locked when it slides into the strip through groove 605.

[0043] The mating ring 602 of the snap-fit ​​end 5 is provided with several elastic contraction rods 501 arranged in a ring array. The telescopic end of the elastic contraction rod 501 is connected to a lever 502. The elastic contraction rod 501 is composed of an outer rod, an inner rod and a highly elastic spring. The inner rod is slidably installed inside the outer rod through the spring, so that although the elastic contraction rod 501 has a certain telescopic capacity, it has a strong retraction capacity when pulled out. That is, it can apply a strong pulling force to the snap-fit ​​end 5 that is snapped by the lever 502, thereby ensuring that the snap-fit ​​end 5 and the mating end 6 can have a high connection strength after connection. In actual use, a sealing ring is installed between the two insulated pipes, and the sealing effect of the sealing ring is ensured by the compression of the snap-fit ​​end 5 and the mating end 6.

[0044] The diameter of the actuating rod 502 is smaller than the diameter of the circular through groove 604 and larger than the width of the strip through groove 605. The diameter of the telescopic end of the elastic retractable rod 501 is smaller than the width of the strip through groove 605, allowing the actuating rod 502 to pass through the circular through groove 604 and then engage with the strip through groove 605. In actual use, a sealing ring is first placed between the snap-fit ​​end 5 and the mating end 6 of the two insulated pipes. Then, the snap-fit ​​end 5 and the mating end 6 are joined together, allowing the actuating rod 502 to pass through the circular through groove 604. Then, the actuating rod 502 is moved into the strip through groove 605, thus securing the actuating rod 502 into the strip through groove 605 and preventing it from detaching. A flange 606 is provided on one side of the combined groove, and the thickness of the flange 606 gradually increases from the circular through groove 604 to the strip through groove 605. A snap-fit ​​ring 503 is fixedly provided on one side of the actuating rod 502. After the actuating rod 502 moves to the end of the strip groove 605, it can be snapped into the flange 606. After the actuating rod 502 slides from the circular groove 604 to the strip groove 605, as the sliding distance increases, the actuating rod 502 will be continuously pushed up by the flange 606, pulling out the elastic telescopic rod. The spring applies a pull-back force, so that the snap-fit ​​end 5 and the mating end 6 can have a high connection strength after connection, so as to ensure the sealing effect of the sealing ring. Compared with the existing pipe connection structure, the present invention adopts a snap-fit ​​structure for assembly, which does not require other installation tools and can be spliced ​​manually. At the same time, it can still maintain a high-strength sealing effect, which greatly improves the installation efficiency of the thermal insulation pipe.

[0045] The pipe wall detection component 7 includes a sleeve ring 701 and an ultrasonic detector 702 fixedly mounted on the inner wall of the sleeve ring 701. The sleeve ring 701 is movably fitted onto the inner steel pipe 1. The outer wall of the sleeve ring 701 has an external thread 703 that connects to the threaded groove 202 of the insulated steel pipe 2. This allows the sleeve ring 701 to slide outside the inner steel pipe 1 while rotating during the lateral movement controlled by the traction component 8 due to the threaded connection with the insulated steel pipe 2. This rotation causes the ultrasonic detector 702 to rotate while laterally moving outside the inner steel pipe 1, allowing the ultrasonic detector 702 to detect the wall thickness of the inner steel pipe 1. This function works in conjunction with a leak detection function. Specifically, when a pipe leak occurs, the signal transmitter 105... Simultaneously with the alarm, the traction component 8 and the ultrasonic detector 702 are also activated. As the traction component 8 moves the connecting ring 701, the ultrasonic detector 702 detects the wall thickness of various parts of the inner steel pipe 1. After detecting the damage, it stops moving. At this time, the connecting ring 701 can also temporarily seal the leak to minimize material leakage in the insulated pipe. In addition, preventive detection can be performed. The detection cycle of the ultrasonic detector 702 can be set to one month or three months as needed to regularly detect the pipeline. When the wall thickness decreases or increases, it indicates that there may be an abnormality inside the pipeline. At this time, staff can be arranged to carry out maintenance, further improving the intelligence level of the insulated pipeline.

[0046] The traction assembly 8 includes a reel 801 and a traction rope 802. The reel 801 consists of a housing, a motor, and a reel connected to the output shaft of the motor. Both the motor and the reel are installed inside the housing. One end of the traction rope 802 is fixed to the reel, and the other end is fixedly connected to the side wall of the sleeve ring 701. The sleeve ring 701 is pulled by the reel 801. When the sleeve ring 701 moves, it can rotate due to the setting of the threaded groove 202 and the internal thread, so as to carry the ultrasonic detector 702 to perform pipe wall detection in multiple directions.

[0047] The foregoing has shown and described the basic principles, main features and advantages of this invention. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of this invention. Various changes and modifications can be made to this invention without departing from the spirit and scope of this invention. All such changes and modifications fall within the scope of this invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-temperature-resistant pre-insulated pipe, characterized in that, Includes the following steps: S1. Preparation of inner steel pipe (1): Using seamless steel pipe as the base of inner steel pipe (1), a central fixing ring (102) is welded at the center position of the inner steel pipe (1). Then, the surface of the inner steel pipe (1) is cleaned to remove oil, rust and dust impurities. Then, the inner steel pipe (1) is treated with anti-corrosion, specifically by coating with anti-corrosion paint or hot-dip galvanizing. S2. Composite layer preparation: The composite layer consists of an insulated steel pipe (2) for mounting on the outer wall of the inner steel pipe (1), a tear-resistant layer (3) wrapped around the insulated steel pipe (2), and an outer protective layer (4) wrapped around the tear-resistant layer (3). Seamless steel pipe is used as the insulated steel pipe (2) installed outside the inner steel pipe (1). A composite fabric woven from cotton fiber and rubber filament is used as the insulation material to prepare the tear-resistant layer (3). The cotton fiber has an insulation effect, and the highly elastic rubber filament can make a loud noise when torn and will rebound to a certain extent. This is used to frighten wild animals when they damage the insulated pipe, so as to avoid further damage to the insulated pipe. The composite fabric is tightly wrapped around the surface of the insulated steel pipe (2) and fixed with wire mesh so that the outer surface of the insulated steel pipe (2) is fully covered with the composite fabric to form an insulated tear-resistant layer (3). Finally, an outer protective layer (4) is wrapped around the outside of the tear-resistant layer (3). S3. Component preparation. The components include an elastic telescopic plug rod (103) for installation on the inner steel pipe (1), a gas density meter (104), a signal transmitter (105), a pipe wall detector (7), and a traction assembly (8) for controlling the movement of the pipe wall detector (7). The pipe wall detector (7) includes a sleeve ring (701) and an ultrasonic detector (702) fixedly installed on the inner wall of the sleeve ring (701). The sleeve ring (701) is movably sleeved on the inner steel pipe (1). The outer wall of the sleeve ring (701) is provided with an external thread (703) that connects to the threaded groove (202) of the heat-insulating steel pipe (2). It also includes a snap-fit ​​end (5) and a butt joint end (6) for connecting the two ends of the inner steel pipe (1) to achieve manual splicing and installation without drive or screws. S4. Component assembly: Drill a number of holes in a uniform circular array on the central fixing ring (102), and install an elastic telescopic plug rod (103) in each hole. Drill four mounting slots symmetrically on the two side walls of the central fixing ring (102), and install a gas density meter (104) and a signal transmitter (105) in the slots. The pipe wall detection component (7) and the traction component (8) are assembled and connected. The traction component (8) is connected to both sides of a single pipe wall detection component (7). The insulation steel pipe (2) in the composite layer is processed with a plug groove (201) and a threaded groove (202). The plug groove (201) is used for the insertion of the elastic telescopic plug rod (103). The composite layer is assembled and connected to the inner steel pipe (1) by inserting the elastic telescopic plug rod (103) into the plug groove (201). Then, the traction component (8) on one side is installed on the side wall of the central fixing ring (102). The pipe wall detection component (7) is then sleeved on the inner steel pipe (1) and then gradually screwed into the interior using the threaded groove (202). The traction component (8) on the other side is installed on the outer protrusion (101). Finally, the outer protrusion (101) is welded to both ends of the inner steel pipe (1). The inner steel pipe is then connected by the outer protrusion (101). (1) Connect and seal with the central fixing ring (102), and then install an air valve on the outer convex edge (101) to fill the cavity between the inner steel pipe (1) and the insulation steel pipe (2) with inert gas. Combined with the anti-tear layer (3) with heat preservation capability, a double heat preservation structure is formed. The inert gas can fill the cavity between the inner steel pipe (1) and the composite layer to reduce the heat conduction effect and improve the heat preservation performance. At the same time, it can make the gas environment density in the cavity different from that of conventional air, which is used for the leakage detection of the gas density meter (104). The detection principle is: after filling with inert gas, the detection value of the gas density meter (104) is constant. When the inner steel pipe (1) is partially cracked or damaged, the inert gas exchanges with the air in the inner steel pipe (1), and the value detected by the gas density meter (104) will change. Then, an alarm signal is sent through the signal transmitter (105). S5. Overall assembly: Install snap-fit ​​ends (5) and butt joint ends (6) on both ends of the assembled inner steel pipe (1) and composite layer, and add sealing gaskets (603) at the connection to complete the preparation of the heat-insulated pipe. The pipes can be connected by the cooperation of snap-fit ​​ends (5) and butt joint ends (6). When a pipeline leak occurs, the signal transmitter (105) issues an alarm, and the traction assembly (8) and ultrasonic detector (702) are also activated simultaneously. During the process of the traction assembly (8) moving the sleeve ring (701), the ultrasonic detector (702) detects the wall thickness of each part of the inner steel pipe (1). After finding the damaged area, it stops moving. At this time, the leak is temporarily sealed by the sleeve ring (701) to reduce the leakage of materials in the insulated pipeline. The detection cycle of the ultrasonic detector (702) is set to one month or three months according to the needs to conduct regular detection of the pipeline. When the wall thickness decreases or increases, it indicates that there may be an abnormality inside the pipeline.

2. The method for preparing a high-temperature resistant prefabricated insulated pipe according to claim 1, characterized in that, Both the snap-fit ​​end (5) and the mating end (6) are composed of an integrally formed sealing cap (601) and mating ring (602). The sealing gasket (603) is located inside the sealing cap (601), and the mating ring (602) is located on the outer side of the sealing cap (601). First, the sealing gasket (603) is placed inside the sealing cap (601), and then the sealing cap (601) is fitted onto the assembled inner steel pipe (1) and the end of the composite layer. The gap between the inner steel pipe (1) and the composite layer is sealed by the sealing gasket (603).

3. The method for preparing a high-temperature resistant prefabricated insulated pipe according to claim 2, characterized in that, The docking end (6) has several combined grooves arranged in a ring array on the docking ring (602), the combined grooves including a circular through groove (604) and a strip through groove (605).

4. The method for preparing a high-temperature resistant prefabricated insulated pipe according to claim 3, characterized in that, The snap-fit ​​end (5) has several elastic retractable rods (501) arranged in a ring array on the docking ring (602). The telescopic end of the elastic retractable rod (501) is connected to a lever (502). The elastic retractable rod (501) is composed of an outer rod, an inner rod and a highly elastic spring. The inner rod is slidably installed inside the outer rod through the spring, so that the elastic retractable rod (501) has a strong retraction ability when pulled out, and can apply a strong pulling force to the snap-fit ​​end (5) snapped by the lever (502), so as to ensure that the snap-fit ​​end (5) and the docking end (6) can have a high connection strength after connection. A sealing ring is installed between the two insulation pipes, and the sealing effect of the sealing ring is ensured by the compression of the snap-fit ​​end (5) and the docking end (6).

5. The method for preparing a high-temperature resistant prefabricated insulated pipe according to claim 4, characterized in that, The diameter of the actuating rod (502) is smaller than the diameter of the circular through groove (604) and larger than the width of the strip through groove (605). The diameter of the telescopic end of the elastic retractable rod (501) is smaller than the width of the strip through groove (605), so that the actuating rod (502) can pass through the circular through groove (604) and then be inserted into the strip through groove (605).

6. The method for preparing a high-temperature resistant prefabricated insulated pipe according to claim 5, characterized in that, A flange (606) is provided on one side of the combined groove. The thickness of the flange (606) gradually increases from the circular through groove (604) to the strip through groove (605). A snap ring (503) is fixedly provided on one side of the actuating rod (502). After the actuating rod (502) moves to the end of the strip through groove (605), it can be snapped into the flange (606). After the actuating rod (502) slides from the circular through groove (604) to the strip through groove (605), as the sliding distance increases, the actuating rod (502) will be continuously pushed up by the flange (606) to pull out the elastic telescopic rod. The spring applies a pull-back force, so that the snap-fit ​​end (5) and the mating end (6) can have a high connection strength after connection, so as to ensure the sealing effect of the sealing ring.

7. The method for preparing a high-temperature resistant prefabricated insulated pipe according to claim 5, characterized in that, The traction assembly (8) includes a reel (801) and a traction rope (802). The reel (801) consists of a housing, a motor, and a reel connected to the output shaft of the motor. The motor and the reel are both installed inside the housing. One end of the traction rope (802) is fixed to the reel, and the other end is fixedly connected to the side wall of the collar (701).

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