An enhanced plastic pipe coupling structure

Abstract

The application relates to the field of plastic pipe connection, in particular to a reinforced plastic pipe connection structure. The reinforced plastic pipe connection structure comprises a socket pipe fitting and a spigot pipe fitting fixed in the socket pipe fitting; an annular pressure response cavity surrounding the spigot pipe fitting is defined between the inner wall of the socket pipe fitting and the outer wall of the spigot pipe fitting, the spigot pipe fitting is provided with a pressure guide channel communicating with the response cavity; an adaptive locking mechanism is further arranged in the response cavity, the adaptive locking mechanism comprises a driving assembly capable of axially sliding along the socket pipe fitting and a plurality of locking assemblies capable of radially sliding along the socket pipe fitting; a limiting reinforcing sleeve is further fixed outside the socket pipe fitting, the limiting reinforcing sleeve extends to the outside of the spigot pipe fitting and is used for gradually elastically limiting the bending deformation of the spigot pipe fitting. The reinforced plastic pipe connection structure can improve the installation stability and use safety of the conveying pipe.

Description

Technical Field

[0001] This invention relates to the field of plastic pipe connections, and more particularly to a reinforced plastic pipe connection structure. Background Technology

[0002] Plastic pipes are widely used in urban water supply and drainage, oil and gas transportation, chemical pipelines, and integrated pipe corridors due to their advantages such as corrosion resistance, light weight, and long service life. The reliability of pipe connections is the lifeline of the entire transportation system; their failure directly leads to leaks, pollution, work stoppages, and even safety accidents.

[0003] In plastic piping systems, especially in applications requiring detachable, repairable, or non-thermofusion-compatible pipes (such as flanged equipment interfaces or transitions between pipes of different materials), threaded locking mechanical connections are a common technique. This involves external threads machined onto the end of the socket fitting, while internal threads or a matching nut are provided on the spigot fitting or a separate connecting sleeve. During installation, the nut is rotated, screwing it along the socket threads to axially press against the sealing ring on the socket end face or the stepped surface of the spigot fitting, achieving a seal and fixation.

[0004] However, the following defects and shortcomings still exist in the process of implementing the application: When the internal pressure of the pipeline increases, the axial force generated by the pressure will further attempt to separate the connection surface, and the fixed thread preload cannot respond to or compensate for this, posing a risk of leakage or disengagement.

[0005] Therefore, it is necessary to provide a new reinforced plastic pipe connection structure to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an enhanced plastic pipe connection structure.

[0007] The reinforced plastic pipe connection structure provided by the present invention includes a socket fitting and a spigot fitting fixed inside the socket fitting; The inner wall of the socket fitting and the outer wall of the spigot fitting define an annular pressure response cavity surrounding the spigot fitting. The spigot fitting has a pressure guiding channel that connects to the response cavity, so as to introduce the internal pressure of the spigot fitting into the response cavity. The response cavity is also equipped with an adaptive locking mechanism, which includes a drive assembly that can slide along the axial direction of the socket fitting and multiple sets of locking assemblies that can slide radially along the socket fitting. The drive assembly and each set of locking assemblies are linked to convert the axial displacement of the drive assembly under pressure into the radial inward movement of each locking assembly, thereby pressing the socket fitting. The socket fitting is also fixed to the outside of a limiting reinforcing sleeve, which extends to the outside of the spigot fitting to provide progressive elastic restraint on the bending deformation of the spigot fitting.

[0008] Preferably, the circumferential surface of the socket fitting has a radially convex thickened portion, and the response cavity is formed within the thickened portion.

[0009] Preferably, the driving component is an annular piston that slides coaxially inside the response chamber. O-rings are provided on both the inner and outer circumferential surfaces of the annular piston to divide the response chamber into a back pressure chamber and a pressure chamber located on both sides of the annular piston. A tension spring is also provided between the inner end wall of the pressure chamber and the annular piston to drive the annular piston to reset. The socket fitting is connected to the pressure chamber through a pressure guiding channel to introduce internal pressure into the pressure chamber.

[0010] Preferably, the pressure guiding channel is a plurality of damping holes formed on the circumferential surface of the socket fitting.

[0011] Preferably, the locking assembly includes a pressing block that slides on the inner end wall of the back pressure chamber, the pressing block having an inclined groove, and a plurality of friction pads that can contact the outer circumferential surface of the socket fitting fixed on one side of the pressing block. The inner end wall of the back pressure cavity is provided with multiple circumferentially distributed guide grooves, and the extrusion block is installed inside the guide grooves.

[0012] Preferably, the annular piston has a transmission block fixed on the side facing the back pressure chamber, which corresponds one-to-one with the locking assembly. The transmission block has an integrally connected inclined plate, which slides inside the inclined groove.

[0013] Preferably, the limiting and reinforcing sleeve includes an installation cylinder coaxially fixed to the outside of the socket fitting, and one end of the installation cylinder is integrally connected with a plurality of circumferentially distributed pressure plates, the cross-section of which is arc-shaped.

[0014] Preferably, the mounting cylinder is positioned corresponding to the protruding section, and there is an annular gap between the mounting cylinder and the protruding section, with a damping pad provided inside the annular gap; The fitting has an integrally connected mounting plate on its outer circumferential surface, and the mounting cylinder is fixed to the mounting plate.

[0015] Preferably, the socket portion of the socket fitting has an external thread, and the spigot fitting is fixed to the socket fitting by a nut.

[0016] Compared with related technologies, the reinforced plastic pipe connection structure provided by the present invention has the following beneficial effects: By combining a socket fitting, an internal annular piston, a compression block, a transmission block, and an external limiting and reinforcing sleeve, a pipe connection structure with adaptive locking and bending resistance is formed. Compared to traditional threaded connections that rely on a fixed preload, this structure utilizes the internal fluid pressure of the pipe to drive the locking mechanism, achieving dynamic adaptive enhancement where "the higher the pressure, the tighter the lock." This solves the problem of preload attenuation and leakage risks caused by material creep, vibration, and pressure shock in traditional connections. By linking the annular piston and the extrusion block through a transmission block and incorporating a return spring, the locking force can be adjusted automatically and in real time according to changes in the internal pressure of the pipeline system. When the internal pressure of the pipeline system increases, the pressure drives the annular piston to move axially, which in turn drives the extrusion block to move radially inward to compress the pipeline. When the pressure decreases, the spring drives the piston to return to its original position, and the locking force decreases accordingly, thus avoiding unnecessary long-term overload. By installing a reinforcing sleeve structure with a pressure plate and a damping pad on the outside of the socket fitting, and fixing its position in the corresponding response cavity, when the spigot fitting bends due to external loads, the pressure plate can provide a progressive restraining force to limit the bending curvature, while the damping pad can absorb vibration. This not only positions the spigot fitting but also provides a certain degree of protection for the socket fitting. Attached Figure Description

[0017] Figure 1 A schematic diagram of a preferred embodiment of the reinforced plastic pipe connection structure provided by the present invention; Figure 2 This is a schematic diagram of the structure of the socket pipe fitting and spigot pipe fitting connected together as shown in this invention; Figure 3 This is a partial cross-sectional structural schematic diagram of the socket pipe fitting shown in this invention; Figure 4 This is a schematic diagram of the internal structure of the socket fitting shown in this invention; Figure 5 This is a schematic diagram of the annular piston structure shown in this invention; Figure 6 This is a schematic diagram of the structure of the annular piston and the extrusion block connected in the present invention; Figure 7 This is a schematic diagram of the extrusion block shown in the present invention; Figure 8 This is a schematic diagram of the limiting and reinforcing sleeve shown in the present invention; Figure 9 This is a schematic diagram of the structure of the socket fitting shown in this invention.

[0018] The following are the labels in the diagram: 1. Socket fitting; 2. Mounting plate; 3. Response chamber; 4. Back pressure chamber; 5. Pressure chamber; 6. Annular piston; 7. O-ring seal; 8. Tension spring; 9. Transmission block; 10. Inclined plate; 11. Extrusion block; 12. Inclined groove; 13. Friction pad; 14. Guide groove; 15. Socket fitting; 16. Nut; 17. Damping hole; 18. Mounting cylinder; 19. Damping pad; 20. Pressure plate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0021] Please see Figures 1 to 9 The present invention provides an enhanced plastic pipe connection structure, which includes a socket fitting 1, a spigot fitting 15, an adaptive locking mechanism, and a limiting reinforcement sleeve sleeved on the outside of the socket fitting 1.

[0022] Please see Figure 2 The end of the socket fitting 1 is a socket portion for installing the spigot fitting 15, and an external thread is machined on the outer circumferential surface of the socket portion. The spigot fitting 15 is initially axially fixed inside the socket fitting 1 by engaging the external thread with a matching nut 16.

[0023] Please see Figure 3 and Figure 9 On the circumferential surface of the socket fitting 1, a radially convex annular thickened section is designed. Inside this thickened section, an annular cavity surrounding the axis is formed, namely the response cavity 3. This cavity is located between the inner wall of the socket fitting 1 and the outer wall of the insertion part of the spigot fitting 15. On the wall of the spigot fitting 15, a plurality of tiny damping holes 17 are evenly distributed circumferentially. These damping holes 17 smoothly guide the pressure of the working medium inside the pipe into the response cavity 3, while attenuating pressure fluctuations.

[0024] Please see Figures 3 to 7 The adaptive locking mechanism is located in the response cavity 3, and includes a driving component and multiple locking components, which are linked together.

[0025] The drive assembly consists of an annular piston 6, coaxially aligned with the response chamber 3 and capable of axial sliding. O-rings 7 are fitted onto both the inner and outer circumferential surfaces of the annular piston 6, tightly dividing the response chamber 3 into two sub-chambers: a back pressure chamber 4 near the insertion end of the connector 15 and a pressure chamber 5 away from the insertion end of the connector 15. A damping hole 17 on the connector 15 faces and communicates with the pressure chamber 5. A tension spring 8 connects the end wall of the pressure chamber 5 to the corresponding end face of the annular piston 6. In the absence of internal pressure or under low pressure, the tension of the spring 8 causes the annular piston 6 to tend to move towards the pressure chamber 5, thus returning to its reset state.

[0026] The locking assembly consists primarily of a compression block 11. Multiple circumferentially distributed guide grooves 14 are machined on the end wall of the back pressure chamber 4, with a compression block 11 slidably mounted within each guide groove 14. A friction pad 13 is adhered to the side of the compression block 11 facing the socket fitting 15, for direct contact and gripping of the outer wall of the socket fitting 15. An inclined groove 12 is formed on the back side of the compression block 11.

[0027] For each extrusion block 11, a transmission block 9 is fixed on the end face of the annular piston 6 facing the back pressure chamber 4, and a protruding inclined plate 10 is connected to the transmission block 9. The end of the inclined plate 10 is inserted into and slidably fitted in the inclined groove 12 of the extrusion block 11, thereby forming an inclined surface transmission pair that converts axial motion into radial motion.

[0028] Please see Figure 1 and Figure 8 The limiting and reinforcing sleeve includes an installation cylinder 18, and the outer circumferential surface of the socket fitting 1 has an integrally formed installation plate 2. The installation cylinder 18 is fixed to the installation plate 2 by bolts. An annular gap is maintained between the inner wall of the installation cylinder 18 and the outer wall of the thickened part of the socket fitting 1. A damping pad 19 made of high-damping rubber material is filled in this gap to uniformly distribute stress, absorb vibration, and provide heat insulation. At the end of the installation cylinder 18 facing the spigot fitting 15, multiple elastic pressure plates 20 with pre-bent arcs are integrally extended circumferentially and evenly distributed. The inner diameter of these pressure plates 20 is slightly smaller than or equal to the outer diameter of the spigot fitting 15, so that they slightly contact or are very close to the outer wall of the pipe when no external force is applied. This allows the pressure plates 20 to provide a gradual restraining force to limit the bending curvature when the spigot fitting 15 bends due to external load, while the damping pad 19 absorbs vibration. While positioning the spigot fitting 15, it also provides a certain degree of protection for the socket fitting 1.

[0029] The working principle and process of this embodiment are as follows: First step: Insert the end of the spigot fitting 15 into the socket of the socket fitting 1 to the predetermined depth, and then tighten the nut 16 to complete the mechanical fixing and initial sealing of the foundation. At this time, the adaptive locking mechanism is in standby state: the tension spring 8 keeps the annular piston 6 in the reset position, the compression block 11 is in a radially contracted state under the action of elastic force, and the friction pad 13 has not yet pressed the pipe.

[0030] The second step: When the piping system begins to transport fluid and generate pressure, the pressure enters the pressure chamber 5 through the damping orifice 17. The pressure acts on the end face of the annular piston 6, generating an axial thrust. When this thrust overcomes the preload of the tension spring 8, it pushes the annular piston 6 to move axially towards the back pressure chamber 4. The movement of the annular piston 6 drives the inclined groove 12 on the extrusion block 11 through the inclined plate 10 on it. Due to the inclined surface, the axial displacement of the annular piston 6 is converted into the radial inward displacement of the extrusion block 11. Multiple extrusion blocks 11 move radially inward synchronously, tightly gripping the outer circumferential surface of the spigot fitting 15 through the friction pads 13 on them, generating a radial locking force. Moreover, this locking force is proportional to the system pressure, realizing a dynamic adaptive enhancement of "the higher the pressure, the stronger the locking".

[0031] The third step: When the pipeline tends to bend due to external factors (such as foundation settlement), the spigot fitting 15 will deflect relative to the socket fitting 1. At this time, the elastic pressure plate 20 on the limiting reinforcing sleeve begins to function. The arc-shaped design of the pressure plate 20 allows it to conform to the initial bend of the pipeline, providing a gradually increasing constraint reaction force through its own elastic deformation, limiting further increase in the bending curvature. At the same time, the localized concentrated stress generated by the bend is dispersed and absorbed by the mounting sleeve 18 and the internal damping pad 19 to prevent stress from acting on the threaded connection or the root of the socket. The damping characteristics of the damping pad 19 can also attenuate the vibration transmission of the pipeline.

[0032] Fourth step: After long-term operation, if the pressure plate 20 of the limiting reinforcement sleeve shows irreversible deformation, it indicates that the connection point has experienced a large abnormal load and requires close attention. If disassembly is required, the system pressure can be released first. Under the action of the tension spring 8, the annular piston 6 will reset, causing the compression block 11 to loosen radially, and then the nut 16 can be unscrewed for maintenance. The mounting cylinder 18, as an independent component, is also easy to replace individually.

[0033] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A reinforced plastic pipe connection structure, comprising a socket fitting (1) and a spigot fitting (15) fixed inside the socket fitting (1), characterized in that: The inner wall of the socket fitting (1) and the outer wall of the spigot fitting (15) define an annular pressure response cavity (3) surrounding the spigot fitting (2). The spigot fitting (15) has a pressure guiding channel that connects to the response cavity (3) so as to introduce the internal pressure of the spigot fitting (15) into the response cavity (3). The response cavity (3) is also provided with an adaptive locking mechanism. The adaptive locking mechanism includes a drive assembly that can slide along the axial direction of the socket fitting (1) and multiple sets of locking assemblies that can slide along the radial direction of the socket fitting (1). The drive assembly and each set of locking assemblies are linked to convert the axial displacement of the drive assembly under pressure into the radial inward movement of each locking assembly, thereby pressing the socket fitting (15). The socket fitting (1) is also fixed to the outside of a limiting reinforcement sleeve, which extends to the outside of the spigot fitting (15) to provide progressive elastic restraint on the bending deformation of the spigot fitting (15).

2. The reinforced plastic pipe connection structure according to claim 1, characterized in that, The circumferential surface of the socket fitting (1) has a radially convex thickened portion, and the response cavity (3) is formed in the thickened portion.

3. The reinforced plastic pipe connection structure according to claim 2, characterized in that, The driving component is an annular piston (6) that slides coaxially inside the response chamber (3). The inner and outer circumferential surfaces of the annular piston (6) are provided with O-ring seals (7) to divide the response chamber (3) into a back pressure chamber (4) and a pressure chamber (5) located on both sides of the annular piston (6). A tension spring (8) is also provided between the inner end wall of the pressure chamber (5) and the annular piston (6) to drive the annular piston (6) to reset. The socket fitting (15) is connected to the pressure chamber (5) through a pressure guiding channel to introduce internal pressure into the pressure chamber (5).

4. The reinforced plastic pipe connection structure according to claim 3, characterized in that, The pressure guiding channel is a plurality of damping holes (17) opened on the circumferential surface of the socket fitting (15).

5. The reinforced plastic pipe connection structure according to claim 4, characterized in that, The locking assembly includes a pressing block (11) that slides on the inner end wall of the back pressure chamber (4). The pressing block (11) has a groove (12) and a plurality of friction pads (13) that can contact the outer circumferential surface of the plug fitting (15) are fixed on one side of the pressing block (11). The inner end wall of the back pressure cavity (4) is provided with multiple circumferentially distributed guide grooves (14), and the extrusion block (11) is installed inside the guide grooves (14).

6. The reinforced plastic pipe connection structure according to claim 5, characterized in that, The annular piston (6) is fixed with a transmission block (9) corresponding to the locking assembly on the side facing the back pressure chamber (4). The transmission block (9) has an integrally connected inclined plate (10), which slides inside the inclined groove (12).

7. The reinforced plastic pipe connection structure according to claim 6, characterized in that, The limiting reinforcement sleeve includes an installation cylinder (18) coaxially fixed to the outside of the socket pipe fitting (1). One end of the installation cylinder (18) is integrally connected with a plurality of circumferentially distributed pressure plates (20), and the cross section of the pressure plates (20) is arc-shaped.

8. The reinforced plastic pipe connection structure according to claim 7, characterized in that, The mounting cylinder (18) is positioned corresponding to the protruding section, and there is an annular gap between it and the protruding section, and a damping pad (19) is provided inside the annular gap. Among them, the outer circumferential surface of the socket fitting (1) has an integrally connected mounting plate (2), and the mounting cylinder (18) is fixed on the mounting plate (2).

9. The reinforced plastic pipe connection structure according to claim 7, characterized in that, The socket portion of the socket fitting (1) has an external thread, and the spigot fitting (15) is fixed to the socket fitting (1) by a nut (16).

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