A prefabricated insulated ductile iron flexible pipe for heating pipe network

Abstract

The present invention discloses a prefabricated insulated ductile iron flexible pipe for a heating pipe network, comprising a pipe and a joint, wherein two pipes are symmetrically inserted into the two ends of the joint, and a gap is provided between the pipe and the joint for enabling the pipe to deflect; the two ends of the joint are provided with three grooves from outside to inside, namely an outer groove, a push groove, and an inner groove; an outer sealing ring is placed in the outer groove, an inner sealing ring is placed in the inner groove, a push-and-hold assembly is provided in the push groove, and the push-and-hold assembly pushes and holds the outer sealing ring and the inner sealing ring tightly; the push-and-hold assembly comprises a plurality of push-and-hold groups, each of which comprises a base arc plate, an outer push plate, and an inner push plate, the base arc plate is slidably connected to the outer push plate and the inner push plate, and the outer push plate and the inner push plate respectively push the outer sealing ring and the inner sealing ring to seal and hold. The present invention is provided with an outer sealing ring and an inner sealing ring to form a double seal, and further utilizes screws to push the outer push plate and the inner push plate to hold the two sealing rings tightly, so as to achieve a good sealing effect.

Description

Technical Field

[0001] The invention relates to the field of heating pipes, in particular to a prefabricated insulation layer ductile iron flexible pipe for a heating pipe network. Background Art

[0002] Existing heating pipe networks mostly use gray cast iron pipes, which have the advantages of easy smelting, low price, and good corrosion resistance. However, gray cast iron also has extremely low ductility, making it highly brittle and extremely fragile. Existing gray cast iron pipes can only be rigidly connected. Even small angles of deflection require custom-made elbows. Therefore, when geological disasters occur, gray cast iron pipes often rupture due to geological activity, interrupting heating. Due to this rigid connection, gray cast iron pipes must be equipped with compensators to accommodate volume changes caused by thermal expansion and contraction to avoid damage to the pipe fittings. Furthermore, gray cast iron pipes are difficult to connect to each other and must be heat-welded and wrapped in multiple layers to ensure a seal. This construction process is time-consuming and labor-intensive.

[0003] Gray cast iron pipes still account for a significant portion of existing heating pipe systems. The main advantages of this material are: 1) a mature smelting process, enabling easy industrial production; 2) cost-effectiveness; and 3) excellent corrosion resistance, particularly in buried environments.

[0004] However, gray cast iron pipes have the following technical defects:

[0005] 1. Mechanical performance limitations

[0006] Gray cast iron has very low ductility (typically less than 1%), making it highly brittle and prone to sudden cracking under external impact or stress concentration conditions.

[0007] 2. Rigid connection

[0008] Existing gray cast iron pipes generally use rigid joints, which have the following structural characteristics: 1) The ability to adjust the angles between pipe sections is insufficient, and even slight deflections require the customization of special elbow fittings; 2) The joints rely on hot-melt welding and multi-layer sealing and wrapping processes, which significantly prolongs the construction period and consumes a lot of manpower.

[0009] 3. Weak ability to resist geological disasters

[0010] When foundation settlement or seismic activity causes soil displacement, the rigid connection system cannot absorb stress through deformation, resulting in a chain reaction of pipeline ruptures and interruption of heating supply.

[0011] 4. High dependence on thermal compensation

[0012] Due to the dual effects of material thermal expansion coefficient and joint stiffness, pipe networks must be equipped with additional compensators, such as bellows compensators and sleeve compensators, to eliminate thermal expansion and contraction stress. Otherwise, pipe joint failure or pipe cracking will occur.

[0013] 5. High maintenance complexity

[0014] Repairing a rupture requires cutting and replacing the entire pipe section, and on-site welding and sealing are subject to environmental conditions, significantly increasing maintenance costs and system downtime.

[0015] Studies have shown that the above defects are directly related to the flaky graphite microstructure of gray cast iron, which leads to the interruption of stress transfer path and the decrease of resistance to crack propagation. The current technological development of the industry has tended to use ductile materials such as ductile iron to replace traditional gray cast iron pipes. Summary of the Invention

[0016] The object of the present invention is to provide a prefabricated insulated ductile iron flexible pipe for a heating pipe network, so as to solve the problems raised in the above background technology.

[0017] To achieve the above-mentioned object, the present invention provides the following technical solution: a prefabricated insulated ductile iron flexible pipe for a heating pipe network, comprising a pipe and a joint, wherein two pipes are symmetrically inserted into the joint at both ends, and a gap is provided between the pipes and the joint to enable the pipes to deflect;

[0018] The two ends of the joint are provided with three grooves from outside to inside, namely an outer groove, a push groove and an inner groove;

[0019] The cross section of the outer groove is a right triangle;

[0020] The cross section of the inner groove is L-shaped;

[0021] An outer sealing ring is placed in the outer groove, an inner sealing ring is placed in the inner groove, and a pushing and pressing component is provided in the push groove, which pushes and presses the outer sealing ring and the inner sealing ring;

[0022] The side of the outer sealing ring close to the outer groove bevel is arc-shaped, and the side of the outer sealing ring close to the push groove is flat;

[0023] The inner sealing ring is fixedly connected to a raised edge on one side close to the push groove, and the raised edge enters the L-shaped bottom edge of the inner groove to form a seal;

[0024] The pushing and pressing assembly includes a plurality of pushing and pressing groups, each pushing and pressing group includes a base arc plate, an outer pushing plate, and an inner pushing plate. The base arc plate is slidably connected to the outer pushing plate and the inner pushing plate, and the outer pushing plate and the inner pushing plate respectively push the outer sealing ring and the inner sealing ring to seal and press;

[0025] The base arc plate is fixedly connected with a screw rod, and the screw rod is threadedly connected with a screw.

[0026] Preferably, the pipe is provided with a flange at the insertion end, and after the pipe is inserted into the joint, the flange is located inside the outer sealing ring and outside the push groove.

[0027] Preferably, a plurality of sliding grooves are provided between the outer groove and the push groove.

[0028] Preferably, the plane side of the outer sealing ring is fixedly connected to a plurality of pressure blocks, with two pressure blocks forming a group.

[0029] Preferably, a slope is provided on one side of the outer sealing ring close to the joint port to facilitate the insertion of the pipe.

[0030] Preferably, multiple sections of the base arc plate, the outer push plate, and the inner push plate can be spliced ​​together to form a full circle.

[0031] Preferably, the push plate is fixedly connected to push blocks, the number of push blocks is half of the pressure blocks, each push block pushes two pressure blocks, and the push blocks are slidably connected in the slide groove.

[0032] Preferably, both the pressure block and the extrapolation block are provided with inclined surfaces for causing the pressure block to be pressed toward the pipeline.

[0033] Preferably, the outside of the joint is further provided with a plurality of rib grooves for accommodating reinforcing ribs, the rib grooves are parallel to the axis of the joint, and each reinforcing rib is rotatably connected to two screws, the positions of the screws corresponding to the positions of the push grooves at both ends of the joint.

[0034] Preferably, the screw passes through the joint and is threadedly connected to the screw rod, and the end of the screw close to the base arc plate is set to a gradient diameter, which is thinner at the position close to the base arc plate and thicker at the position away from the base arc plate. The gradient diameter contacts and connects the outer push plate and the inner push plate, and the screw is rotated to push the outer push plate and the inner push plate to tighten the outer sealing ring and the inner sealing ring.

[0035] Compared with the prior art, the beneficial effects of the present invention are: the pipe made of ductile iron in the present invention has high strength, good toughness, corrosion resistance, good shock resistance, and convenient construction, and the present invention is provided with an outer sealing ring and an inner sealing ring to form a double seal, and further uses screws to push the outer push plate and the inner push plate to compress the two sealing rings, thereby achieving a good sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the main structure of the present invention;

[0037] Figure 2 Schematic diagram of the structure of the connector of the present invention;

[0038] Figure 3 This is a schematic diagram of the cross-section structure of the pipeline and joint of the present invention;

[0039] Figure 4 for Figure 3 A local enlarged view of point A;

[0040] Figure 5 It is a structural schematic diagram of the main section of the present invention;

[0041] Figure 6 for Figure 5 A local enlarged view of point B;

[0042] Figure 7 Schematic diagram of the structure of the outer sealing ring of the present invention;

[0043] Figure 8 It is a structural schematic diagram of the extrapolation plate of the present invention;

[0044] Figure 9 It is a structural schematic diagram of the compression block and the extrapolation block in the present invention in the extrusion state;

[0045] Figure 10 It is a structural schematic diagram of the pipeline of the present invention;

[0046] Figure 11 It is a schematic diagram of the structure of the present invention covered with a thermal insulation layer.

[0047] In the figure: 1. Pipe, 101. Flange, 2. Joint, 201. Outer groove, 202. Push groove, 203. Inner groove, 204. Slide groove, 3. Outer sealing ring, 301. Pressure block, 4. Inner sealing ring, 401. Raised edge, 5. Base arc plate, 501. Outer push plate, 502. Outer push block, 503. Inner push plate, 6. Reinforcement rib, 601. Rib groove, 7. Screw, 701. Screw, 8. Insulation layer, 9. Outer protective tube, 10. Bracket. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] See also Figure 1-11To address the issues of extremely low ductility, rigid connection methods, weak resistance to geological disasters, strong dependence on thermal compensation, and high maintenance complexity of gray cast iron pipes, the present invention aims to achieve pipes made of ductile iron with high strength, good toughness, corrosion resistance, good seismic resistance, and convenient construction. The present invention provides an outer sealing ring 3 and an inner sealing ring 4 to form a double seal, and further utilizes screws 7 to push the outer push plate 501 and the inner push plate 503 to compress the two sealing rings, achieving a good sealing effect. The present invention provides a technical solution: a prefabricated insulated ductile iron flexible pipe for a heating network, comprising a pipe 1 and a joint 2. Two pipes 1 are symmetrically inserted into the ends of the joint 2, with a gap between the pipes 1 and the joint 2 to allow the pipes 1 to deflect. The pipes 1 are provided with a flange 101 at the insertion end. After the pipes 1 are inserted into the joint 2, the flange 101 is located within the outer sealing ring 3 and outside the push groove 202. The pipe 1 is wrapped with an insulation layer 8, and the insulation layer 8 is wrapped with an outer protective tube 9. As needed, a bracket 10 and an alarm line can also be set in the insulation layer 8. The pipe 1 and the joint 2 are made of ductile iron, the insulation layer is made of polyurethane, the outer protective tube is made of PE, and the outer sealing ring 3 and the inner sealing ring 4 are made of existing materials. When in use, first bend the outer sealing ring 3 and the inner sealing ring 4 and put them into the outer groove 201 and the inner groove 203 of the joint 2, and place the pressure block 301 of the outer sealing ring 3 to the side of the push groove 202, and the raised edge 401 of the inner sealing ring 4 to the side of the push groove 202. The outer sealing ring 3 and the inner sealing ring 4 are expanded due to their own elasticity, and the outer sealing ring 3 and the inner sealing ring 4 are placed into the outer groove 201 and the inner groove 203. Then install the pushing and pressing assembly, install the outer push plate 501 into the push groove 202, align the outer push block 502 on the outer push plate 501 with the slide groove 204, and then install the inner push plate 503 into the push groove 202 , and then install the base arc plate 5 into the push groove 202, aligning the screw 701 on the base arc plate 5 with the hole on the joint 2 for passing the screw 7, and at the same time placing the reinforcing rib 6 in the rib groove 601, passing the screw 7 through the reinforcing rib 6 and the joint 2 and threading it on the screw 701, and not tightening it. At this time, the base arc plate 5, the outer push plate 501, and the inner push plate 503 are all suspended in the push groove 202; after all the outer sealing ring 3, the inner sealing ring 4, the reinforcing rib 6, the screw 7, and the pushing and clamping components are installed, insert the pipe 1 into the joint 2, and then turn the screw 7 to press down to tighten the outer sealing ring 3 and the inner sealing ring 4.

[0050] By spheroidizing the molten iron, the graphite's form within the cast iron matrix is ​​altered, transforming from the flakes found in ordinary cast iron to spherical forms. This imparts excellent ductility while retaining the corrosion resistance of ordinary cast iron. Pipes made from ductile iron possess numerous advantages, including high strength, toughness, corrosion resistance, seismic resistance, and ease of construction. Ductile iron pipelines offer excellent resistance to electrochemical corrosion, extending their service life to 50 years. Ductile iron also boasts a high resistivity of 50-70 μΩ / cm³, approximately three times that of carbon steel. Furthermore, the insulating rubber seals at the pipe joints generally eliminate the need for cathodic protection. Unlike steel pipes, which use rigid welded joints, ductile iron pipes utilize flexible, spigot-and-socket connections, offering superior safety and significantly reducing the risk of accidents in heating pipelines. Flexible joints offer a secure and reliable seal. Thermal expansion and contraction of the pipe do not affect the joint seal, significantly reducing the risk of pipeline leakage. Flexible joints are capable of deflection and expansion, minimizing damage to the pipe caused by uneven foundation settlement and ensuring stable operation of the heating system. Flexible joints feature installation clearances to fully release thermal expansion forces generated by ambient temperature differences, eliminating the need for compensators. This reduces leakage caused by structural damage due to inadequate compensation design and reduces the number of leak points. Ductile iron (ductile iron) pipes significantly reduce stress levels in the pipeline, reaching only one-third that of steel pipes. Ductile iron pipes are simple and convenient to construct and install, with installation speeds 5 to 10 times greater than steel pipes. Their safe operating lifespan is more than twice that of steel pipes, offering significant advantages over steel pipes in terms of lifecycle costs. Maintenance costs are also low during operation. Repairs do not require extensive modifications to the entire pipeline system; damaged pipe sections or joints can simply be replaced, resulting in lower maintenance costs and time, resulting in lower overall costs.

[0051] To facilitate installation and sealing, three grooves are provided at both ends of the joint 2 from outside to inside: an outer groove 201, a push groove 202, and an inner groove 203. Several sliding grooves 204 are provided between the outer groove 201 and the push groove 202. The cross-section of the outer groove 201 is a right triangle; the cross-section of the inner groove 203 is L-shaped. The side of the inner sealing ring 4 near the push groove 202 is fixedly connected to a raised edge 401, which enters the L-shaped bottom edge of the inner groove 203 to form a seal. The outer sealing ring 3 is placed in the outer groove 201, and the inner sealing ring 4 is placed in the inner groove 203. A pushing and pressing assembly is provided in the push groove 202, which pushes and presses the outer sealing ring 3 and the inner sealing ring 4 together. The side of the outer sealing ring 3 near the hypotenuse of the outer groove 201 is arc-shaped, and the side of the outer sealing ring 3 near the push groove 202 is flat. The flat side of the outer sealing ring 3 is fixedly connected to several pressure blocks 301, with two pressure blocks 301 in a group. The outer sealing ring 3 is provided with an inclined surface on the side near the end of the connector 2 to facilitate the insertion of the pipe 1. During the insertion process, the pipe 1 is pushed to move, which drives the flange 101 to move. The flange 101 is guided by the inclined surface of the outer sealing ring 3 and can pass over the outer sealing ring 3. The outer sealing ring 3 is restricted by the outer groove 201 and cannot move. When the end face of the pipe 1 passes over the inner sealing ring 4, the movement of the pipe 1 can be stopped. At this time, the outer sealing ring 3 and the inner sealing ring 4 can be further compressed by the pushing and pressing assembly.

[0052] To further tighten the outer seal ring 3 and the inner seal ring 4, a push-and-press assembly is provided. The push-and-press assembly includes multiple push-and-press groups, each of which includes a base arc plate 5, an outer push plate 501, and an inner push plate 503. The outer push plate 501 and the inner push plate 503 are slidably connected to the base arc plate 5. The outer push plate 501 and the inner push plate 503 respectively push the outer seal ring 3 and the inner seal ring 4 to seal and compress them. Multiple sections of the base arc plate 5, the outer push plate 501, and the inner push plate 503 can be spliced ​​together to form a complete circle. The outer push plate 501 is fixedly connected to an outer push block 502. The number of outer push blocks 502 is half of the number of pressure blocks 301. Each outer push block 502 pushes two pressure blocks 301. The outer push blocks 502 are slidably connected in the chute 204. The pressure blocks 301 and the outer push blocks 502 are both provided with inclined surfaces that compress the pressure blocks 301 toward the pipeline 1. When the screw 7 is pressed down, the gradual diameter of the screw 7 pushes the outer push plate 501 and the inner push plate 503 in contact with it. The outer push plate 501 and the inner push plate 503 slide on the base arc plate 5, and the outer push plate 501 drives the outer push block 502 to move. The outer push block 502 slides in the slide groove 204. One outer push block 502 pushes the two pressure blocks 301 in contact with it, and applies an outward centripetal force to the pressure block 301 through the action of the inclined surface, so that the pressure block 301 moves away from the push groove 202 and close to the pressure block 301. The pipe 1 moves in the direction of rotation, and the pressure block 301 drives the outer sealing ring 3 to move, so that the arc-shaped side of the outer sealing ring 3 rests on the oblique side of the outer groove 201 to form an outer seal; the inner push plate 503 pushes the inner sealing ring 4 to move, and the inner sealing ring 4 drives the raised edge 401 to move, so that the raised edge 401 is pressed on the L-shaped short side of the inner groove 203 to form an inner seal. Under the double seal, the seal between the pipe 1 and the joint 2 is ensured, and at the same time, it can ensure that the pipe 1 does not leak during the deflection activity.

[0053] To further strengthen the joint 2, several grooves 601 are provided on the outside of the joint 2 for accommodating reinforcing ribs 6. These grooves 601 are parallel to the axis of the joint 2. Two screws 7 are rotatably connected to each rib 6, and their positions correspond to the push grooves 202 at each end of the joint 2. The screws 7 pass through the joint 2 and are threadedly connected to the screw rods 701. The screws 7 are fixedly connected to the base arc plate 5. The end of the screw 7 near the base arc plate 5 is configured with a tapered diameter, becoming thinner near the base arc plate 5 and thicker farther away. This tapered diameter contacts and connects the outer push plate 501 and the inner push plate 503. Rotating the screw 7 pushes the outer push plate 501 and the inner push plate 503, thereby compressing the outer sealing ring 3 and the inner sealing ring 4. Rotating the screw 7 causes the screw 7 to move toward the center of the pipe 1 due to the thread action, driving the reinforcing rib 6 into the grooves 601. When the screw 7 is rotated to its maximum distance, the reinforcing rib 6 is fully embedded in the grooves 601.

[0054] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A prefabricated insulated ductile iron flexible pipe for a heating network, comprising a pipe (1) and a joint (2), wherein two pipes (1) are symmetrically inserted into both ends of the joint (2), and characterized in that: There is a gap between the pipe (1) and the joint (2) for enabling the pipe (1) to deflect; The two ends of the joint (2) are provided with three grooves from outside to inside, namely an outer groove (201), a push groove (202), and an inner groove (203); The cross section of the outer groove (201) is a right triangle; The cross section of the inner groove (203) is L-shaped; An outer sealing ring (3) is placed in the outer groove (201), an inner sealing ring (4) is placed in the inner groove (203), and a pushing and pressing assembly is provided in the push groove (202), and the pushing and pressing assembly pushes and presses the outer sealing ring (3) and the inner sealing ring (4); The side of the outer sealing ring (3) close to the bevel of the outer groove (201) is arc-shaped, and the side of the outer sealing ring (3) close to the push groove (202) is flat; The inner sealing ring (4) is fixedly connected to a raised edge (401) on one side close to the push groove (202), and the raised edge (401) enters the L-shaped bottom edge of the inner groove (203) to form a seal; The pushing and pressing assembly includes a plurality of pushing and pressing groups, each pushing and pressing group includes a base arc plate (5), an outer pushing plate (501), and an inner pushing plate (503), the base arc plate (5) is slidably connected to the outer pushing plate (501) and the inner pushing plate (503), and the outer pushing plate (501) and the inner pushing plate (503) respectively push the outer sealing ring (3) and the inner sealing ring (4) to seal and press; The base arc plate (5) is fixedly connected with a screw rod (701), which is threadedly connected to the screw (7).

2. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 1, characterized in that: The pipe (1) is provided with a flange (101) at the insertion end. After the pipe (1) is inserted into the joint (2), the flange (101) is located inside the outer sealing ring (3) and outside the push groove (202).

3. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 1, characterized in that: A plurality of sliding grooves (204) are provided between the outer groove (201) and the push groove (202).

4. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 3, characterized in that: The plane side of the outer sealing ring (3) is fixedly connected to a plurality of pressure blocks (301), with two pressure blocks (301) forming a group.

5. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 1, characterized in that: A sloped surface is provided on one side of the outer sealing ring (3) close to the port of the joint (2) to facilitate insertion of the pipe (1).

6. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 1, characterized in that: Multiple sections of the base arc plate (5), the outer push plate (501), and the inner push plate (503) can be spliced ​​together to form a full circle.

7. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 1, characterized in that: The push plate (501) is fixedly connected to the push block (502), the number of the push blocks (502) is half of the pressure blocks (301), each push block (502) pushes two pressure blocks (301), and the push blocks (502) are slidably connected in the slide groove (204).

8. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 7, characterized in that: The pressure block (301) and the push block (502) are both provided with inclined surfaces for causing the pressure block (301) to be pressed in the direction of the pipeline (1).

9. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 1, characterized in that: The joint (2) is further provided with a plurality of rib grooves (601) for accommodating reinforcing ribs (6), the rib grooves (601) being parallel to the axis of the joint (2), and each reinforcing rib (6) being rotatably connected to two screws (7), the positions of the screws (7) corresponding to the positions of the push grooves (202) at both ends of the joint (2).

10. The prefabricated insulated ductile iron flexible pipe for a heating network according to claim 9, characterized in that: The screw (7) passes through the joint (2) and is threadedly connected to the screw rod (701). The end of the screw (7) close to the base arc plate (5) is set to a gradually changing diameter, which is thinner at a position close to the base arc plate (5) and thicker at a position away from the base arc plate (5). The gradually changing diameter contacts and connects the outer push plate (501) and the inner push plate (503). Rotating the screw (7) pushes the outer push plate (501) and the inner push plate (503), thereby pressing the outer sealing ring (3) and the inner sealing ring (4).

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