Terminal for PE electrofusion fitting and PE electrofusion fitting

Abstract

The present application discloses a terminal for a PE electrofusion fitting and a PE electrofusion fitting, which relate to polyethylene pipes for buried pipelines. The terminal is formed by stamping a copper alloy plate, and the terminal includes: a hollow cylinder, a connecting section, and a rectangular base. After the terminal is tightly engaged with the resistance wire, it is integrally injection-molded into the body of the PE electrofusion fitting. The terminal of the present application is formed by stamping a copper alloy, which greatly saves copper resources while ensuring performance, reduces costs and improves processing efficiency. By adopting a specific hollow structure composed of a hollow cylinder, a connecting section and a rectangular base, which is tightly engaged with the resistance wire and then integrally injection-molded into the body of the PE electrofusion fitting, it effectively avoids the problem of welding failure of the PE electrofusion fitting caused by poor contact due to insufficient interference, effectively improves the electrical performance of the PE electrofusion fitting, and greatly ensures the use safety of the PE electrofusion fitting.

Description

Technical Field

[0001] This application relates to polyethylene (hereinafter referred to as PE) pipes for buried pipelines, and particularly to a terminal for a PE electrofusion fitting and a PE electrofusion fitting. Background Art

[0002] The PE pipes for buried pipelines include PE pipes and buried pipeline connectors. The buried pipeline connectors include PE electrofusion fittings. The PE electrofusion fitting is a PE fitting with resistance wires embedded inside. The PE electrofusion fitting includes a PE main body, resistance wires embedded in the inner wall of the PE main body, and terminals. Among them, two wiring ports are correspondingly provided at positions near the ends of the PE fitting, and each wiring port is internally provided with a terminal, and the terminal is connected to the resistance wire. During welding, after the two PE pipes to be welded are inserted into the same PE electrofusion fitting from two directions, the electrofusion welder energizes the resistance wires embedded in the PE electrofusion fitting through the terminals, thereby heating and melting the inner surface of the PE electrofusion fitting and the outer surface of the adjacent PE pipes. After the melted part cools, the PE electrofusion fitting and the two PE pipes form an integral body, thus completing the connection of the two PE pipes.

[0003] The terminal is a key connecting part for the electrofusion welder to energize the PE electrofusion fitting. The existing terminals are all solid terminal posts made of copper rods. The upper part is a solid cylinder for connecting to the external electrofusion welder, and the lower part is a bamboo joint type base or a protruding solid base for connecting to the PE main body by interference press-fitting. There are fine holes on the base for initial positioning when winding the resistance wire.

[0004] In the prior art, the terminal is made of solid copper metal, resulting in a high cost problem. The connection method between the terminal and the heating wire is either winding and then press-fitting together by interference, or a mechanical method of drilling a hole and then inserting the heating wire into the hole and then clamping it flat. The above connection methods all have insufficient interference, and often cause poor contact due to pressure changes during power-on, resulting in welding failure. Summary of the Invention

[0005] The purpose of this application is to overcome the above problems or at least partially solve or alleviate the above problems.

[0006] According to one aspect of this application, a terminal for a PE electrofusion fitting is provided, which is used to connect and energize the resistance wire embedded in the PE electrofusion fitting with an external electrofusion welder. The terminal is formed by stamping a copper alloy plate, and the terminal includes:

[0007] A hollow cylinder, located at the upper part, the outer diameter of the hollow cylinder is a standard size for connecting to an external electrofusion welder. A PE material inlet is provided on the wall surface of the hollow cylinder, and the inside of the hollow cylinder is used to be filled with PE material;

[0008] A connecting section, located in the middle, is formed by the partial arc-shaped wall of the bottom surface of the hollow cylinder extending downward, and is used to connect the hollow cylinder and the rectangular base; and

[0009] A rectangular base, located at the lower part, is formed by the connecting section extending downward to form a first section, bending toward the opposite end of the connecting section in the hollow cylinder to form a second section, then bending upward to form a third section, and then bending toward the connecting section to form a fourth section, finally forming a rectangular base that penetrates left and right. A slender groove is provided in the third section of the rectangular base in the axial direction parallel to the axis of the terminal, for embedding the resistance wire and forming a firm bite;

[0010] Wherein, after the terminal is firmly bitten with the resistance wire, the whole is injection-molded into the body of the PE electrofusion fitting.

[0011] Optionally, there are two symmetric protrusions on both sides of the first section of the rectangular base for injection-molding positioning, and the protruding direction of each protrusion is perpendicular to the axis of the slender groove.

[0012] Optionally, the outer diameter of the hollow cylinder is Φ4mm or Φ4.7mm.

[0013] Optionally, the width of the slender groove is about 0.75 times the outer diameter of the resistance wire.

[0014] Optionally, the thickness of the copper alloy plate is 0.3mm - 0.8mm.

[0015] According to another aspect of the present application, a PE electrofusion fitting is provided, including a PE body, a PE inner sleeve, a resistance wire and the above-mentioned terminal. Wherein, the PE inner sleeve has a slot for accommodating the rectangular base of the terminal and having an interference fit with it, and multiple annular grooves are provided on the outer wall of the PE inner sleeve for winding and fixing the resistance wire.

[0016] For the terminal for PE electrofusion fitting and the PE electrofusion fitting of the present application, due to the manufacturing method of stamping the terminal from copper alloy, while ensuring performance, it greatly saves copper resources, reduces costs and improves processing efficiency. The present application adopts a specific hollow structure composed of a hollow cylinder, a connecting section and a rectangular base, which is firmly bitten with the resistance wire and then injection-molded into the body of the PE electrofusion fitting as a whole, that is, an integral injection-molding is used to replace the mechanical assembly method, effectively avoiding the problem of welding failure of the PE electrofusion fitting caused by poor contact due to insufficient interference, improving the electrical performance of the PE electrofusion fitting, and greatly ensuring the use safety of the PE electrofusion fitting. Therefore, the present application can improve the electrical performance of the PE electrofusion fitting while reducing costs.

[0017] Those skilled in the art will better understand the above and other objects, advantages and features of the present application from the following detailed description of specific embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Some specific embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings in an illustrative but not restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0019] Figure 1 is a schematic front view of a terminal for a PE electrofusion fitting according to an embodiment of the present application;

[0020] Figure 2 is Figure 1 a schematic left view of the shown terminal;

[0021] Figure 3 is a schematic structural view at the terminal post of a PE electrofusion fitting according to another embodiment of the present application.

[0022] The meanings of the symbols in the drawings are as follows:

[0023] 1 PE electrofusion fitting,

[0024] 10 terminal, 20 resistance wire, 30 PE inner sleeve, 31 slot hole, 32 annular groove, 40 PE body,

[0025] 11 hollow cylinder, 111 PE material inlet,

[0026] 12 connecting section,

[0027] 13 rectangular base, 131 first section, 132 second section, 133 third section, 134 fourth section, 135 elongated slot, 136 protrusion. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Figure 1 is a schematic front view of a terminal for a PE electrofusion fitting according to an embodiment of the present application. Figure 2 is Figure 1 a schematic left view of the shown terminal. Figure 3 is a schematic structural view at the terminal post of a PE electrofusion fitting according to another embodiment of the present application.

[0029] As Figure 1 shown, reference may also be made to Figures 2-3 , this embodiment provides a terminal 10 for a PE electrofusion fitting, which is used to connect an external electrofusion welder to a resistance wire 20 (see Figure 3 ) embedded in the PE electrofusion fitting 1 (see Figure 3)Connect and energize. The terminal 10 is formed by stamping a copper alloy plate, and the thickness of the copper alloy plate is preferably 0.3 mm - 0.8 mm. The terminal 10 includes: a hollow cylinder 11, a connecting section 12, and a rectangular base 13. The hollow cylinder 11 is located at the upper part, and the outer diameter of the hollow cylinder 11 is a standard size for connecting to an external electric fusion welder. The outer diameter of the hollow cylinder 11 is Φ4 mm or Φ4.7 mm. A PE material inlet 111 is provided on the wall surface of the hollow cylinder 11 for the molten PE material to enter during injection molding, and the inside of the hollow cylinder 11 is filled with PE material. The connecting section 12 is located in the middle and is formed by the downward extension of the partial arc wall at the bottom surface of the hollow cylinder 11 for connecting the hollow cylinder 11 and the rectangular base 13. The rectangular base 13 is located at the lower part and is formed by the connecting section 12 extending downward to form a first section 131, then bending toward the opposite end of the connecting section 12 in the hollow cylinder 11 to form a second section 132, then bending upward to form a third section 133, and then bending toward the connecting section 12 to form a fourth section 134, finally forming a rectangular base 13 that penetrates left and right. A slender groove 135 that penetrates the front surface and the rear surface of the third section 133 is provided in the third section 133 of the rectangular base 13 in the direction parallel to the axis of the terminal 10 for the resistance wire 20 to be embedded and form a firm bite. Among them, after the terminal 10 and the resistance wire 20 are firmly bitten, they are integrally injection-molded into the body of the PE electrofusion fitting 1.

[0030] See Figure 3 , the resistance wire 20 is first wound and fixed at the annular groove 32 of the PE inner sleeve 30, then the terminal 10 is inserted into the slot hole 31 of the PE inner sleeve 30 by an interference fit method, and then one end of the resistance wire is embedded into the slender groove 135 of the rectangular base 13 of the terminal 10 and firmly bitten. Then the assembled terminal 10, resistance wire, and PE inner sleeve 30 are placed in a mold and processed into a complete PE electrofusion fitting 1 by an injection molding machine. In the PE electrofusion fitting 1, the inside, outside, the inside and outside of the connecting section 12, and the hollow part of the upper hollow cylinder 11 of the rectangular base 13 of the terminal 10 are all wrapped with PE material, and the PE material plays a role of support, protection, and connection here and forms an organic whole with the PE body 40.

[0031] This application is for the terminal 10 of the PE electrofusion fitting 1. Since the terminal 10 is manufactured by stamping copper alloy, while ensuring performance, it greatly saves copper resources, reduces costs and improves processing efficiency. It adopts a specific hollow structure composed of a hollow cylinder 11, a connecting section 12 and a rectangular base 13. After being tightly engaged with the resistance wire 20, it is integrally injection-molded into the PE body 40. This application uses one-piece injection molding to replace the mechanical assembly method, effectively avoiding the problem of poor contact caused by insufficient interference fit, which leads to the welding failure of the PE electrofusion fitting 1, improving the electrical performance of the PE electrofusion fitting 1, and greatly ensuring the use safety of the PE electrofusion fitting 1. Therefore, this application can improve the electrical performance of the PE electrofusion fitting 1 while reducing costs.

[0032] Further, as Figure 1 shown, it can also be seen in Figure 2 that there are two symmetrical protrusions 136 on both sides of the first section 131 of the rectangular base 13 for injection molding positioning, and the protruding direction of each protrusion 136 is perpendicular to the axis of the elongated groove 135.

[0033] Further, as Figure 1 shown, it can also be seen in Figure 2 that the width of the elongated groove 135 is about 0.75 times the outer diameter of the resistance wire 20 to ensure that the terminal 10 is embedded in the resistance wire 20 for firm connection.

[0034] As Figure 3 shown, this embodiment also provides a PE electrofusion fitting 1, including a PE body 40, a PE inner sleeve 30, a resistance wire 20 and the terminal 10 in the above embodiment. Among them, the PE inner sleeve 30 has a slot hole 31 for accommodating the rectangular base 13 of the terminal 10 and having an interference fit with the rectangular base 13, and multiple annular grooves 32 are provided on the outer wall of the PE inner sleeve 30 for winding and fixing the resistance wire 20.

[0035] The PE electrofusion fitting 1 of the present application includes the terminal 10 in the above embodiment, and thus also has all its advantages. In the present application, since the terminal 10 is manufactured by stamping copper alloy, while ensuring the performance, it greatly saves copper resources, reduces the cost and improves the processing efficiency. Adopting a specific hollow structure composed of a hollow cylinder 11, a connecting section 12 and a rectangular base 13 and tightly engaging with the resistance wire 20 and then integrally injecting into the PE body 40, the present application uses integral injection molding to replace the mechanical assembly method, effectively avoiding the problem of welding failure of the PE electrofusion fitting 1 caused by poor contact due to insufficient interference fit, improving the electrical performance of the PE electrofusion fitting 1, and greatly ensuring the use safety of the PE electrofusion fitting 1. Therefore, the present application can improve the electrical performance of the PE electrofusion fitting 1 while reducing the cost. Therefore, the present application can improve the electrical performance of the PE electrofusion fitting 1 while reducing the cost.

[0036] It should be noted that unless otherwise specified, the technical terms or scientific terms used in the present application should have the ordinary meanings understood by those skilled in the art to which the present application belongs.

[0037] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0038] In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. In the description of the present application, the meaning of "a plurality" is more than two, unless otherwise specifically defined.

[0039] In the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0040] In this application, unless otherwise clearly stipulated and defined, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0041] As mentioned above, the above are only the preferred specific embodiments of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A terminal for a PE electrofusion fitting, which is used to connect an external electrofusion welding machine to a resistance wire embedded in the PE electrofusion fitting for power supply. Characterized in that, the terminal (10) is formed by stamping a copper alloy plate, and the terminal (10) includes: A hollow cylinder (11), located at the upper part, the outer diameter of the hollow cylinder (11) is a standard size, which is used to connect with an external electrofusion welding machine. A PE material inlet (111) is provided on the wall surface of the hollow cylinder (11), and the inside of the hollow cylinder (11) is used to be filled with PE material; A connecting section (12), located in the middle, is formed by the local arc wall of the bottom surface of the hollow cylinder (11) extending downward, and is used to connect the hollow cylinder (11) and the rectangular base (13); and A rectangular base (13), located at the lower part, is formed by the connecting section (12) extending downward to form a first section (131), bending towards the opposite end of the connecting section (12) in the hollow cylinder to form a second section (132), then bending upward to form a third section (133), and then bending towards the connecting section (12) to form a fourth section (134), finally forming a rectangular base (13) that penetrates left and right. A slender groove (135) parallel to the axis direction of the terminal (10) is provided in the third section (133) of the rectangular base (13), which penetrates the front surface and the rear surface of the third section (133), and is used to embed the resistance wire and form a firm bite; wherein, after the terminal (10) is firmly bitten with the resistance wire, it is integrally injection-molded into the body of the PE electrofusion fitting; There are two symmetrical protrusions (136) on both sides of the first section (131) of the rectangular base (13), which are used for injection molding positioning, and the protruding direction of each protrusion (136) is perpendicular to the axis of the slender groove (135); The outer diameter of the hollow cylinder is Φ4mm or Φ4.7mm.

2. The terminal according to claim 1, Characterized in that, The width of the slender groove (135) is about 0.75 times the outer diameter of the resistance wire.

3. The terminal according to any one of claims 1-2, Characterized in that, The thickness of the copper alloy plate is 0.3mm - 0.8mm.

4. A PE electrofusion fitting, Characterized in that, It includes a PE body (40), a PE inner sleeve (30), a resistance wire (20) and the terminal (10) according to any one of claims 1-3. Among them, the PE inner sleeve (30) has a slot hole (31), which is used to accommodate the rectangular base (13) of the terminal (10) and has an interference fit with it. A plurality of annular grooves (32) are provided on the outer wall of the PE inner sleeve (30), which are used to wind and fix the resistance wire (20).

Images