A PE pipe fitting induction welding joint and an induction welding method

Abstract

The present invention discloses a PE pipe fitting induction welding joint and an induction welding method, including a joint body. The joint body includes an interface, and a metal layer is provided on the inner peripheral wall of the interface. The metal layer has an annular structure and is provided with a channel penetrating through the inner and outer peripheries of the metal layer. The metal layer is a metal mesh structure, and a plurality of through holes are provided on the side wall of the metal layer. An observation hole is provided on the side wall of the interface. One end of the observation hole can communicate with the metal layer, and the other end opens towards the outer wall of the interface. The present invention uses induction heating to heat and melt the materials around the mesh, and enables the surface materials in contact with the pipe fittings to be welded through melting and then cooling.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe fittings, and more specifically, to an induction welding joint for PE pipe fittings, and also to an induction welding method for PE pipe fittings. Background Art

[0002] When connecting some pipe fittings and joints, electric fusion welding is used to achieve welding. For the pipe fitting joint of electric fusion welding, during the production process, a metal conductive wire is preset inside the joint layer, and a power connection point is formed outside the pipe fitting. During the welding process, the power supply is connected to the conductive wire, and the conductive wire acts as a heating wire and can generate heat. The materials near the conductive wire will be heated and melted, thereby realizing the welding and fixing of the pipe fitting joint and the pipe.

[0003] The joint of electric fusion welding has high requirements for the wiring and materials of the internal conductive wire. The conductive wire needs to be energized to generate heat, and then electric fusion welding can be achieved. However, during the production process and operation process, problems such as broken wire and short circuit are likely to occur inside the joint of electric fusion welding, resulting in the inability of the conductive wire to conduct electricity and generate heat smoothly, and local normal heating cannot be achieved. Local welding defects are likely to occur during welding, resulting in poor welding quality.

[0004] Therefore, a new solution needs to be proposed to solve this problem. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art, and provide an induction welding joint and an induction welding method for PE pipe fittings, which can achieve welding by electromagnetic induction.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] An induction welding joint for PE pipe fittings includes a joint body. The joint body includes an interface, and a metal layer is provided on the inner peripheral wall of the interface. The joint body and the metal layer are integrally injection-molded. The metal layer is in a ring structure and is provided with a channel penetrating the inner and outer peripherals of the metal layer. A protruding limiting portion is formed on the inner periphery of the interface, and the limiting portion is used to block and position the pipe body inserted into the interface. The first end of the metal layer faces the open side of the interface, and the other end is the second end. A first cooling area is formed between the first end of the metal layer and the open mouth of the interface, and a second cooling area is formed between the second end of the metal layer and the limiting portion.

[0008] The present invention is further provided that the metal layer is in a ring-shaped spring structure, and the metal layer can elastically expand and contract along the length direction.

[0009] The present invention is further configured such that the metal layer gradually narrows towards the second end, a lining layer is formed between the metal layer and the inner peripheral surface of the interface, and the thickness of the lining layer gradually narrows towards the second end of the metal layer.

[0010] The present invention is further configured such that two observation holes are provided on the side wall of the interface, namely a first observation hole and a second observation hole. The first observation hole is located at the outer peripheral position of the first end of the metal layer, and the second observation hole is located at the outer peripheral position of the second end of the metal layer.

[0011] The present invention is further configured to further include a support member. The support member has a rod-shaped structure. A part of the support member is fixedly connected to the first end of the metal layer, and the other part extends towards the joint body and is fixedly connected to the joint body by embedding.

[0012] The present invention is further configured such that the joint body includes two joints. The two joints are arranged coaxially. The metal layers are provided on the inner walls of the two joints, and both ends of the support member are fixedly connected to the two joints on both sides.

[0013] The present invention is further configured such that the metal layer is a metal mesh structure, and a plurality of through holes are provided on the side wall of the metal layer.

[0014] The present invention is further configured such that an observation hole is provided on the side wall of the interface. One end of the observation hole can communicate with the metal layer, and the other end opens towards the outer wall of the interface.

[0015] The present invention also provides an induction welding method for a PE pipe fitting, including a pipe body and the PE pipe fitting induction welding joint as described above. The outer diameter of the pipe body is adapted to the inner diameter of the interface. The pipe body is inserted into the interface, and the metal layer in the interface is heated by electromagnetic induction. The materials on the inner layer of the interface and the outer layer of the pipe body are melted after being heated, and are welded and fixed to each other after cooling.

[0016] In summary, the present invention has the following beneficial effects:

[0017] By providing an annular metal layer in the joint, heating can be achieved by electromagnetic induction. After heating, the surrounding materials are heated and melted, and the surface materials in contact with the pipe fittings are bonded together after melting and cooling. By using electromagnetic induction for heating, the layout structure of the metal layer inside the joint can be simplified. Compared with the joints of electrofusion welding, the production requirements are lower, the manufacturing cost can be reduced, and moreover, the problems of broken wires and short circuits that are prone to occur during the welding process of the joints of electrofusion welding can be overcome, and the problem of water leakage caused by uneven welding and missed welding during the welding process can be avoided.

[0018] By using a spring as the metal layer, the spring can achieve elastic deformation in the length direction. During the induction welding process, the inserted pipe fitting will drive the spring and the nearby molten material to adhere. The adhesion effect can drive the spring to produce a small deformation. After the pipe fitting is completely inserted, the spring will gradually elastically recover, forming a pressure effect, enabling the local molten material to gather towards the middle section of the metal layer. The molten material can be gathered to ensure that the two can be effectively welded and fixed.

[0019] By pre-burying and fixing the support member in the joint, the first end of the metal layer can be supported and fixed, enabling the first end of the metal layer to maintain a stable position even in the molten state. During the welding process, the support member can always be fixed. Therefore, during the elastic expansion and contraction of the second end of the metal layer, the first end of the metal layer is basically not affected by displacement, and thus the structure of the metal layer can be kept basically stable. Brief Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of a PE pipe fitting induction welding joint in the first embodiment;

[0021] Figure 2 It is a cross-sectional view of a PE pipe fitting induction welding joint in the first embodiment;

[0022] Figure 3 It is a schematic external structural diagram of a PE pipe fitting induction welding joint in the first embodiment;

[0023] Figure 4 It is a cross-sectional view of a PE pipe fitting induction welding joint in the second embodiment;

[0024] Figure 5 It is a schematic structural diagram of the metal layer in the second embodiment;

[0025] Figure 6 It is a schematic structural diagram after the joint body is connected to the pipe body in the second embodiment.

[0026] Reference Numerals: Joint Body 1; Interface 2; First Cooling Zone 21; Second Cooling Zone 22; Metal Layer 3; First End 31; Second End 32; Lining Layer 33; Limiting Portion 4; Observation Hole 5; First Observation Hole 51; Second Observation Hole 52; Support Member 6; Pipe Body 7. Detailed Embodiments

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] Example 1

[0029] This embodiment discloses an induction welding joint for PE pipe fittings. Referring to Figure 1 、 Figure 2 and Figure 3 as shown, it includes a joint body 1. A metal layer 3 is provided on the inner peripheral wall of the interface 2. The joint body 1 and the metal layer 3 are integrally injection molded; the metal layer 3 is in an annular structure and is lined on the inner layer of the interface 2. During induction welding, an electromagnetic heater is used to heat-treat the joint body 1, and eddy currents are generated in the metal layer 3 by electromagnetic induction to achieve heating, thereby melting the materials near the metal layer 3, and then the joint body 1 can be welded to the inserted pipe body 7 to realize electromagnetic induction welding and fixation of the two.

[0030] Taking the joint body 1 as a tee for example, it has three interfaces, and at least one of the interfaces is provided with a metal layer 3, which can realize electromagnetic induction welding.

[0031] In order to realize the flow of the molten material, a plurality of channels are opened on the side wall of the metal layer 3. Through the channels, the inner and outer layers of the metal layer 3 can be connected, so that the molten plastic material can flow smoothly. On the one hand, during the injection molding process, the material of the joint body 1 can partially penetrate through the metal layer 3, so that the metal layer 3 and the joint body 1 can adhere to form a whole; on the other hand, during the welding process of the joint body 1 and the pipe body 7, the molten plastic material can flow inside and outside the metal layer 3 and blend with each other to ensure that the two can be welded to form a whole, which is beneficial to the welding strength of the two.

[0032] Specifically, the metal layer 3 can be made of stainless steel material, which has good rust prevention performance. After welding and forming, it can avoid the occurrence of rust inside and extend the service life of the pipe fittings. The structure of the metal layer 3 can be a mesh structure processed from stainless steel metal wires, and a plurality of through holes are formed on the surface, which are used as the above-mentioned channels.

[0033] An observation hole 5 is opened on the side wall of the interface 2. One end of the observation hole 5 can communicate with the vicinity of the metal layer 3, and the other end opens towards the outer wall of the interface 2. During the induction welding process, the materials near the metal layer 3 will be heated and melted. The melted materials have a certain fluidity. Under the condition of being inserted and extruded by the pipe body 7, the melted materials will enter the observation hole 5 and gradually overflow outside the observation hole 5. At this time, it indicates that the two have been welded and the induction power supply can be removed. Through the observation hole 5, it is convenient for the operator to observe to judge the welding situation.

[0034] Referring to Figure 1 、 Figure 2As shown, a protruding limiting portion 4 is formed on the inner circumference of the interface 2. The limiting portion 4 is generally an annular convex structure and has a stepped surface facing the interface 2. When the pipe body 7 is inserted into the interface 2, the end of the pipe body 7 can abut against the limiting portion 4 to ensure that the pipe body 7 is inserted into the interface 2 to a certain depth, ensuring the strength performance after the two are welded.

[0035] Along the axial direction of the interface 2, the two ends of the metal layer 3 are respectively the first end and the second end. Among them, the first end 31 of the metal layer 3 is the open side facing the interface 2, and the second end 32 of the metal layer 3 is the open side facing away from the interface 2, and the second end 32 faces the direction of the limiting portion 4.

[0036] Along the axial direction of the interface 2, the length of the metal layer 3 is shorter than the distance from the open end of the interface 2 to the limiting portion 4, and the metal layer 3 cannot completely cover the range from the open end of the interface 2 to the limiting portion 4. A first cooling zone 21 is formed between the first end 31 of the metal layer 3 and the open end of the interface 2, and a second cooling zone 22 is formed between the second end 32 of the metal layer 3 and the limiting portion 4. There is no metal layer 3 at the first cooling zone 21 and the second cooling zone 22. During the induction welding process, the materials at the first cooling zone 21 and the second cooling zone 22 will not be melted. When the melted materials flow to the first cooling zone 21 and the second cooling zone 22, the temperature will decrease, and a cooling blocking area can be formed at both axial ends of the metal layer 3 to prevent the melted materials from overflowing the welding area, resulting in lack of materials and false soldering, and ensuring stable welding fixation in the connection area.

[0037] This embodiment also discloses an induction welding method for PE pipe fittings. This induction welding method welds the pipe body 7 and the induction welding joint of the PE pipe fitting in the above embodiment. The outer diameter of the pipe body 7 is adapted to the inner diameter of the interface 2, and the end of the pipe body 7 can be inserted into the interface 2. The insertion depth of the pipe body 7 can be positioned through the limiting portion 4.

[0038] During welding, first insert the pipe body 7 to be welded into the interface 2, and use electromagnetic induction heating to heat the metal layer 3 in the interface 2. The materials on the inner layer of the interface 2 and the outer layer of the pipe body 7 are melted by heat and are welded and fixed to each other after cooling.

[0039] During the welding process, observe through the observation hole 5 whether there is material overflow to judge whether the induction heating is completed. When there is material overflow, the heating effect is achieved, and the power supply for the induction heating can be turned off. After welding is completed, the welded part of the pipe fitting needs to be kept for 3 - 8 minutes without shaking or displacement to prevent de-soldering.

[0040] By using the method of electromagnetic induction for welding, the labor and material costs of traditional electrofusion wire routing can be changed. The requirements for the metal layer 3 in induction welding are relatively low, and the manufacturing cost of the joint can be significantly reduced.

[0041] Traditional electrofusion welding has high requirements for the welding voltage. The welding process requires joints for connecting wires, which is not only cumbersome to operate but also has certain safety hazards. Electromagnetic induction has low requirements for voltage and does not require strict voltage control at the construction site. It is convenient to operate and safe and reliable.

[0042] In traditional electrofusion welding, the metal mesh inside the joint needs to conduct current and act as a heating wire, so there are certain requirements for the continuity of the metal mesh. Problems such as broken wires and short circuits are likely to occur inside the electrofusion welding joint, and local leakage welding is likely to occur during welding, resulting in local water leakage problems. In the solution of this embodiment, the metal layer 3 is heated by electromagnetic induction, and heat is generated by the eddy current inside the metal material. As long as the metal material exists in the induction area, heating can be achieved. Induction welding is relatively stable, and problems such as broken wires and short circuits will not affect the actual welding effect.

[0043] Embodiment Two

[0044] This embodiment discloses a PE pipe fitting induction welding joint. On the basis of Embodiment One, with reference to Figure 4 、 Figure 5 and Figure 6 for a detailed description, the shape and structure of the metal layer 3 are further designed.

[0045] With reference to Figure 4 、 Figure 5 shown, in this embodiment, the metal layer 3 is in a ring-shaped spring-like structure and has certain elastic properties, capable of elastic expansion and contraction along the length direction.

[0046] Moreover, the metal layer 3 gradually narrows towards the second end 32 direction, forming a necked structure. A lining layer 33 is formed between the metal layer 3 and the inner peripheral surface of the interface 2. The lining layer 33 has a certain thickness, and its thickness is slightly thicker at the position of the first end 31 of the metal layer 3 and gradually decreases towards the second end 32 direction.

[0047] During the electromagnetic welding process, the joint 2 can be preheated first, and the materials near the metal layer 3 will gradually be heated and melted. Since the lining layer 33 on the inner circumference of the second end 32 of the metal layer 3 is thinner and easier to be completely melted, while the lining layer 33 on the inner circumference of the first end 31 of the metal layer 3 is thicker and cannot be completely melted in a short time.

[0048] After preheating, the tube body 7 to be welded is inserted into the interface 2. During the insertion process, since the vicinity of the second end 32 of the metal layer 3 has melted, the outer peripheral wall of the tube body 7 can adhere to the material near the second end 32 of the metal layer 3, thereby driving the second end 32 of the metal layer 3 to move toward the limit portion 4. The spring-shaped metal layer 3 will also be driven, thereby causing the metal layer 3 to elastically stretch, and the second end 32 of the metal layer 3 will stretch toward the limit portion 4.

[0049] Then, electromagnetic induction heating is continued to heat the metal layer 3 in the interface 2, and the materials of the inner layer of the interface 2 and the outer layer of the tube body 7 continue to be heated and gradually melted until the lining layer 33 on the inner periphery of the first end 31 of the metal layer 3 is also completely melted.

[0050] After the metal layer 3 is elastically stretched, as the material near the metal layer 3 melts, the second end 32 of the metal layer 3 will elastically recover, and the second end 32 will elastically retract toward the first end 31, thereby driving the material near the second end 32 of the metal layer 3 to move, and the molten material will gather from the second end 32 toward the first end 31 of the metal layer 3, so that the material near the second end 32 of the metal layer 3 can gather in the middle section of the metal layer 3, and then the molten material can achieve melt welding in the middle section of the metal layer 3, ensuring that the two can be welded and fixed.

[0051] After the molten material cools down, the joint body 1 and the tube body 7 can be welded and fixed to each other.

[0052] Furthermore, for joints with larger pipe diameters, a flexible metal mesh layer structure can be coated on the outer periphery of the spring-shaped metal layer 3, so that a metal layer covering structure can also be formed outside the spring-shaped metal layer 3, thereby facilitating eddy currents in the spring-shaped metal layer 3 and the metal mesh, making it easier to achieve heating. Moreover, the metal mesh is also partially bonded and fixed to the spring-shaped metal layer 3, and the flexible metal mesh will not affect the elastic expansion and contraction of the metal layer 3.

[0053] Reference Figure 5 As shown, a support member 6 is embedded in the joint 2, and the support member 6 is a rod-shaped structure. A portion of the support member 6 is fixedly connected to the first end 31 of the metal layer 3, and another portion extends toward the joint body 1 and is embedded and fixedly connected to the joint body 1.

[0054] By pre-burying and fixing the support member 6 within the joint 2, the first end 31 of the metal layer 3 can be supported and fixed. Moreover, since the first end 31 of the metal layer 3 is connected to the support member 6 and a portion of the support member 6 is pre-buried in the middle section of the joint 2, the support member 6 can always be fixed during the welding process. Therefore, at the second end 32 of the metal layer 3, during the elastic expansion and contraction process, the first end 31 of the metal layer 3 is basically not affected by displacement, and thus the structure of the metal layer 3 can be kept basically stable.

[0055] Furthermore, two observation holes 5 are provided on the side wall of each interface 2, namely a first observation hole 51 and a second observation hole 52. Among them, the first observation hole 51 is opened at the outer peripheral position of the first end 31 of the metal layer 3, and the second observation hole 52 is opened at the outer peripheral position of the second end 32 of the metal layer 3. Thus, the melting conditions of the materials at two positions can be realized at the two observation holes 5, and the melting conditions at multiple positions in the length direction of the metal layer 3 can be ensured, which is conducive to conveniently observing the melting state of the material within the joint 2.

[0056] Refer to Figure 6 As shown, the joint body 1 includes two joints 2, and the two joints 2 are arranged coaxially. The two joints 2 axially penetrate through both ends of the joint body 1, and openings are formed at both ends.

[0057] And, metal layers 3 are provided on the inner walls of the two joints 2. The support member 6 adopts a rod-shaped structure, and both ends of the support member 6 are fixedly connected to the two joints 2 on both sides. The middle section of the support member 6 is pre-buried and fixed in the joint 2. During the welding process, one of the metal layers 3 will melt during the welding process, while the other metal layer 3 will always remain in a fixed state and can be supported by the joint body 1. In addition, a plurality of support members 6 are fixedly connected outside the two metal layers 3. Thus, a plurality of support members 6 can be arranged in the circumferential direction of the metal layer 3 for support, and the stability between the two metal layers 3 can be ensured, maintaining the stability of the metal layer 3.

[0058] The above are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. An induction welding joint for PE pipe fittings, characterized in that, It includes a joint body (1), the joint body (1) includes an interface (2), a metal layer (3) is provided on the inner peripheral wall of the interface (2), the joint body (1) and the metal layer (3) are integrally injection-molded, the metal layer (3) is in a ring structure and is provided with a channel penetrating the inner and outer circumferences of the metal layer (3); a protruding limiting part (4) is formed on the inner circumference of the interface (2), and the limiting part (4) is used to block and position the pipe body (7) inserted into the interface (2); the first end of the metal layer (3) facing the open side of the interface (2) is the first end (31), and the other end is the second end (32). A first cooling zone (21) is formed between the first end (31) of the metal layer (3) and the open mouth of the interface (2), and a second cooling zone (22) is formed between the second end (32) of the metal layer (3) and the limiting part (4). The metal layer (3) is in a ring-shaped spring-like structure, and the metal layer (3) can elastically expand and contract along the length direction. The metal layer (3) gradually narrows towards the second end (32). A lining layer (33) is formed between the metal layer (3) and the inner peripheral surface of the interface (2), and the thickness of the lining layer (33) gradually narrows towards the second end (32) of the metal layer (3). It further includes a support member (6), the support member (6) is in a rod-like structure. One part of the support member (6) is fixedly connected to the first end (31) of the metal layer (3), and the other part extends towards the joint body (1) and is fixedly connected to the joint body (1) by embedding.

2. The induction welding joint of a PE pipe fitting according to claim 1, characterized in that, Two observation holes (5) are provided on the side wall of the interface (2), namely a first observation hole (51) and a second observation hole (52). The first observation hole (51) is located at the outer peripheral position of the first end (31) of the metal layer (3), and the second observation hole (52) is located at the outer peripheral position of the second end (32) of the metal layer (3).

3. A kind of induction welding joint for PE pipe fittings according to claim 1, characterized in that, The joint body (1) includes two interfaces (2), the two interfaces (2) are arranged coaxially, and the metal layers (3) are provided on the inner walls of the two interfaces (2). Both ends of the support member (6) are fixedly connected to the two interfaces (2) on both sides.

4. The induction welding joint of a PE pipe fitting according to claim 1, characterized in that The metal layer (3) is in a metal mesh structure, and a number of through holes are provided on the side wall of the metal layer (3).

5. A PE pipe fitting induction welding joint according to claim 4, characterized in that, An observation hole (5) is provided on the side wall of the interface (2). One end of the observation hole (5) can communicate with the metal layer (3), and the other end is open towards the outer wall of the interface (2).

6. An induction welding method for PE pipe fittings, characterized in that, It includes a pipe body (7) and a PE pipe fitting induction welding joint as described in any one of claims 1-5. The outer diameter of the pipe body (7) is adapted to the inner diameter of the interface (2); during electromagnetic welding, the interface (2) is preheated, the lining layer at the inner circumference of the second end (32) is completely melted, and the lining layer (33) at the inner circumference of the first end (31) is not completely melted; after preheating, the pipe body (7) is inserted into the interface (2), and the metal layer (3) in the interface (2) is heated by electromagnetic induction heating. The materials of the inner layer of the interface (2) and the outer layer of the pipe body (7) are melted by heat, and after cooling, the joint body (1) and the pipe body (7) are welded and fixed to each other.

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