Pouring type XLPE cable major insulation recovery device and use method thereof

Abstract

The invention discloses a pouring type XLPE cable main insulation recovery device and a using method thereof, and relates to the field of cable laying construction, the pouring type XLPE cable main insulation recovery device comprises a heating unit, a heat preservation pipe and a mold unit, and the heating unit comprises a heating tank used for heating crosslinked polyethylene. On the basis that a cable core and an inner semi-conductor are recovered, two cable joints are placed between an upper template and a lower template, the upper template and the lower template are fixed on a supporting seat of a vibration table through bolts, cross-linked polyethylene liquid is injected into the upper template and the lower template, and in the injection process, the cross-linked polyethylene liquid is injected into the upper template and the lower template; the two groups of electric heating wires can continuously heat the crosslinked polyethylene liquid in the upper template and the lower template, and meanwhile, the vibration table works and is used for discharging bubbles in the crosslinked polyethylene liquid, so that the crosslinked polyethylene liquid uniformly fills a cavity, the main insulation of a cable is recovered to be uniform, the overall performance of the intermediate joint is improved, and the service life of the intermediate joint is longer; the power supply reliability is improved.

Description

Technical Field

[0001] The invention belongs to the field of cable laying construction, and in particular relates to a pouring type XLPE cable main insulation recovery device and a use method thereof. Background Art

[0002] Cross-linked polyethylene cable is composed of outer sheath, metal armor, inner sheath, filler, copper shielding layer, outer semi-conducting layer, insulating layer, inner semi-conducting layer, conductor, core, etc., among which the insulating layer is made of cross-linked polyethylene.

[0003] After the cable is laid, in order to make it a continuous line, each section must be connected as a whole, and these connection points are called cable joints. The cable joint in the middle of the cable line is called the intermediate joint (abbreviated as the intermediate head), and the cable joints at both ends of the line are called terminal heads.

[0004] After the cable route is put into operation, the intermediate joints and outdoor terminal heads are the weakest and most vulnerable links in the entire line. According to statistics, the failure rate of the intermediate joints accounts for more than 85% of the total failures. After the intermediate joint fails, it is necessary to remake the intermediate joint, so the number of intermediate joints should be minimized. However, due to production process and transportation reasons, the length of a cable drum is 250-500m, so the production of intermediate joints is almost unavoidable. At the same time, due to the uneven craftsmanship of the production personnel and the quality of cable accessories, it is always difficult to achieve the life of the cable body by relying on manually made intermediate joints. Common cable intermediate joints are made in the form of cold shrink, heat shrink, hot melt, etc.

[0005] The manufacturing process of heat shrinkable cable intermediate joint is simple, and it is light, cheap and easy to maintain, but the material itself has no elasticity, only the function of "elastic memory"; the main insulation part of the cold shrinkable cable intermediate joint adopts a method of close cooperation with the cable insulation, and uses the high elasticity of rubber to keep a certain pressure on the interface for a long time, and the insulation performance is stable. At the same time, there is also a carefully designed stress cone inside it, which properly solves the problem of stress concentration at the cut-off point. The cold shrinkable cable intermediate joint has the advantages of good electrical performance, heat resistance, flame retardancy, aging resistance and long service life, but its mechanical strength is poor. At present, the cold shrinkable cable intermediate joint has gradually replaced the heat shrinkable intermediate joint and is widely used in the power system; the hot melt intermediate joint adopts the method of winding cross-linked polyethylene tape and then heating to melt and connect the wire core, inner shield, main insulation and outer shield into one, enhance the waterproof and insulation performance of the cable, and greatly extend the life of the cable intermediate joint, but it is expensive.

[0006] The above cable intermediate joint production methods all have certain limitations. The best performance is the hot-melt cable intermediate joint, which is not only expensive, but also takes a lot of time to produce, up to 5 hours or more, which seriously delays the repair time and power supply time. Therefore, we propose a cast XLPE cable main insulation recovery device and its use method to quickly and cheaply solve the problem of intermediate joint production. Summary of the invention

[0007] Aiming at the problem that a common method for manufacturing a cable intermediate joint has certain limitations, the present invention provides a cast-type XLPE cable main insulation recovery device and a method for using the same.

[0008] The solution adopted by the present invention to solve the technical problem is: a cast XLPE cable main insulation recovery device, comprising a heating unit, an insulation pipe and a mold unit, the heating unit comprising a heating tank for heating cross-linked polyethylene, and a detachable tank cover is arranged on the top of the heating tank; The tank cover is provided with an injection pressure interface, a pressure gauge and a thermometer, and the lower part of the heating tank is provided with a three-way pipe, and the three-way pipe is provided with a valve; The mold unit comprises an upper mold plate and a lower mold plate, the upper mold plate and the lower mold plate are detachably connected, and a cavity for accommodating the cable connector is formed between the upper mold plate and the lower mold plate; The interiors of the upper and lower templates are both hollow, and electric heating wires are installed in the inner cavities of the upper and lower templates respectively; A liquid inlet interface and at least one pressure relief valve are installed on the top of the upper template, and the bottom ends of the liquid inlet interface and the pressure relief valve are respectively connected to the cavity; The two ends of the insulation pipe are detachably connected to the liquid inlet interface and the three-way pipe respectively.

[0009] Preferably, the valve is a manual valve or a solenoid valve.

[0010] Preferably, it also includes a vibration table, on the table top of which two groups of support seats are installed, and the support seats are provided with reserved holes.

[0011] Preferably, a support frame is further included, and the support frame is installed at the bottom of the heating tank.

[0012] Preferably, the two ends of the upper template extend outward to form upper edges on both sides, and the two ends of the lower template extend outward to form lower edges on both sides. The upper edge and the lower edge are respectively provided with through holes connected up and down, and the same bolt is arranged in the upper and lower corresponding reserved holes and the two through holes.

[0013] Preferably, one side of the upper template and the lower template are connected by a hinge, and the other side of the upper template and the lower template are detachably connected by a buckle.

[0014] Preferably, the upper surface of the upper template and the lower surface of the lower template are respectively provided with a heat insulation layer, and both ends of the upper template and the lower template are respectively made of ceramic material.

[0015] A method for using a cast XLPE cable main insulation recovery device comprises the following steps: S1. Use thermite reaction or welding to restore the cable core and polish it smooth; S2. The main insulation at both ends of the cable core is processed into a pencil head shape and polished smooth; S3, restore the inner semi-conductive layer of the cable; S4, placing the lower template on two sets of support seats; S5. Place the cable cores on both sides in the lower mold respectively, and buckle the upper mold onto the lower mold. Then, connect the upper mold, the lower mold and the support base with bolts. For three-core cables, three sets of mold units can be used to restore the main insulation of the three phases at the same time. S6. The solid cross-linked polyethylene liquid in the tank body is heated by a heating tank, the heating temperature is set to 260° C., and the pressure pipe of the pressurizing device is connected to the injection pressure interface; S7. When the center temperature of the cross-linked polyethylene liquid reaches 185°C, the pressurizing device, the vibration table and the two sets of electric heating wires are started one by one. The pressurizing device injects 3.5MPa high-pressure gas into the heating tank. At the same time, the valve is opened to allow the cross-linked polyethylene liquid in the heating tank to be injected between the upper mold plate and the lower mold plate through the insulation pipe. S8, two sets of electric heating wires heat the cross-linked polyethylene liquid in the upper template and the lower template respectively to prevent the cross-linked polyethylene liquid from solidifying, and at the same time the vibration table works to discharge the bubbles in the cross-linked polyethylene liquid; S9. When the pressure relief valve automatically releases pressure and cross-linked polyethylene liquid flows out, close the pressurizing device and valve and stop injecting cross-linked polyethylene liquid; S10, turning off the vibration table and the two sets of electric heating wires to allow the cross-linked polyethylene liquid in the upper mold plate and the lower mold plate to cool automatically; S11. After the cross-linked polyethylene liquid is cooled, remove the bolts one by one, take down the upper template, and complete the main insulation restoration work at the connection between the two cables.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. After the cable is pre-treated, the cable core and the inner semi-conductivity are restored, and then two cable connectors are placed between the upper template and the lower template, and the upper template and the lower template are fixed on the support seat of the vibration table by bolts. The cross-linked polyethylene liquid is injected into the upper template and the lower template. During the injection process, two groups of electric heating wires are used to continuously heat the cross-linked polyethylene liquid in the upper template and the lower template. At the same time, the vibration table works to discharge the bubbles in the cross-linked polyethylene liquid, so that the cross-linked polyethylene liquid uniformly fills the cavity, the main insulation of the cable is restored uniformly, the overall performance of the intermediate joint is improved, the service life of the intermediate joint is extended, the power supply reliability is improved, and the three sets of mold units simultaneously restore the three-phase main insulation, which greatly improves the production speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front view structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the three-dimensional structure of the mold unit and the vibration table of the present invention; Figure 3 It is a schematic diagram of the left-side cross-sectional structure of the mold unit of the present invention; Figure 4 It is a schematic diagram of the front cross-sectional structure of the mold unit of the present invention.

[0018] In the figure: 1 support frame, 2 heating tank, 21 injection pressure interface, 22 pressure gauge, 23 thermometer, 24 tank cover, 25 three-way pipe, 26 valve, 3 insulation pipe, 41 upper template, 42 bolts, 43 lower template, 44 electric heating wire, 45 liquid inlet interface, 46 pressure relief valve, 48 ceramic material, 51 vibration table, 52 support seat. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0020] See also Figure 1-4 The present invention provides a technical solution for a cast XLPE cable main insulation recovery device: Embodiment 1: according to Figure 1-4 As shown, it includes a heating unit, an insulation pipe 3 and a mold unit. The heating unit includes a heating tank 2 for heating cross-linked polyethylene. A detachable tank cover 24 is provided on the top of the heating tank 2. By opening the tank cover 24, the cross-linked polyethylene is placed in the heating tank 2.

[0021] The surfaces of the heating tank 2 and the insulation tube 3 are respectively provided with heat insulation layers, and the heat insulation layers are provided to avoid scalding of the user.

[0022] The tank cover 24 is provided with an injection and pressure interface 21, a pressure gauge 22 and a thermometer 23. A three-way pipe 25 is provided at the lower part of the heating tank 2. A valve 26 is provided on the three-way pipe 25. The valve 26 is a manual valve or a solenoid valve. By providing the three-way pipe 25, three insulation pipes 3 can be passed through at the same time to inject cross-linked polyethylene liquid into the three groups of mold units at the same time, and the main insulation of the three-phase cable can be restored at the same time.

[0023] The vibrating table 51 is also included. Two groups of supporting seats 52 are installed on the table top of the vibrating table 51. The supporting seats 52 are provided with reserved holes.

[0024] The mold unit includes an upper mold plate 41 and a lower mold plate 43. The upper surface of the upper mold plate 41 and the lower surface of the lower mold plate 43 are respectively provided with a heat insulation layer. By providing the heat insulation layer, burns to the user can be avoided.

[0025] The upper template 41 and the lower template 43 are detachably connected, and the specific disassembly method is: the two ends of the upper template 41 extend outward to form upper edges on both sides, and the two ends of the lower template 43 extend outward to form lower edges on both sides. The upper edge and the lower edge are respectively provided with through holes connected to each other up and down, and the same bolt 42 is provided in the upper and lower corresponding reserved holes and the two through holes. While the upper template 41 and the lower template 43 are connected and fixed, the lower template 43 is fixed on the support seat 52, so that the vibration table 51 can drive the upper template 41 and the lower template 43 to vibrate synchronously.

[0026] A cavity for accommodating the cable connector is formed between the upper template 41 and the lower template 43 , so that the processed cable connector can be placed between the upper template 41 and the lower template 43 .

[0027] The parts of the upper and lower templates 41 and 43 that are in contact with the original insulation of the cable are made of ceramic material 48 for heat insulation to prevent high temperature from melting the original insulation.

[0028] The diameter of the cable-accommodating cavity formed between the upper template 41 and the lower template 43 has various sizes, which are suitable for cables with different insulation thicknesses (voltage levels) and different conductor core cross-sectional areas.

[0029] The interior of the upper template 41 and the lower template 43 are both hollow, and electric heating wires 44 are respectively installed in the inner cavities of the upper template 41 and the lower template 43. During the process of injecting cross-linked polyethylene liquid into the upper template 41 and the lower template 43, the two groups of electric heating wires 44 are beneficial to continuously heat the cross-linked polyethylene liquid in the upper template 41 and the lower template 43 to prevent the cross-linked polyethylene liquid from solidifying.

[0030] A liquid inlet interface 45 and at least one pressure relief valve 46 are installed on the top of the upper template 41 , and the bottom ends of the liquid inlet interface 45 and the pressure relief valve 46 are respectively communicated with the cavity.

[0031] Both ends of the insulation pipe 3 are detachably connected to the liquid inlet interface 45 and the three-way pipe 25 , respectively, so that the cross-linked polyethylene liquid in the heating tank 2 is injected into between the upper mold plate 41 and the lower mold plate 43 through the insulation pipe 3 .

[0032] The present invention provides a method for using a cast-type XLPE cable main insulation recovery device, comprising the following steps: S1. Use thermite reaction or welding to restore the cable core and polish it smooth; S2. The main insulation at both ends of the cable core is processed into a pencil head shape and polished smooth; S3, restore the inner semi-conductive layer of the cable; S4, placing the lower template 43 on two sets of support seats 52; S5. Place the cable cores on both sides in the lower mold plate 43 respectively, and buckle the upper mold plate 41 on the lower mold plate 43, and then connect the upper mold plate 41, the lower mold plate 43 and the support seat 52 by bolts 42. For a three-core cable, three sets of mold units can be used at the same time to restore the main insulation of the three phases at the same time; S6, heating the solid cross-linked polyethylene liquid in the tank body by the heating tank 2, the heating temperature is set to 260° C., and at the same time, the pressure pipe of the pressurizing device is connected to the injection pressure interface 21; S7, when the center temperature of the cross-linked polyethylene liquid reaches 185°C, the pressurizing device, the vibration table 51 and the two sets of electric heating wires 44 are started one by one, and the pressurizing device injects 3.5MPa high-pressure gas into the heating tank 2. At the same time, the valve 26 is opened to allow the cross-linked polyethylene liquid in the heating tank 2 to be injected into the space between the upper mold plate 41 and the lower mold plate 43 through the insulation pipe 3; S8, two groups of electric heating wires 44 heat the cross-linked polyethylene liquid in the upper template 41 and the lower template 43 respectively to prevent the cross-linked polyethylene liquid from solidifying, and at the same time the vibration table 51 works to discharge the bubbles in the cross-linked polyethylene liquid; S9, when the pressure relief valve 46 automatically releases pressure and the cross-linked polyethylene liquid flows out, the pressurizing device and the valve 26 are closed, and the injection of the cross-linked polyethylene liquid is stopped; S10, turning off the vibration table 51 and the two sets of electric heating wires 44, so that the cross-linked polyethylene liquid in the upper mold plate 41 and the lower mold plate 43 is automatically cooled; S11. After the cross-linked polyethylene liquid is cooled, the bolts 42 are removed one by one, and the upper template 41 is removed to complete the main insulation restoration work at the connection between the two cables.

[0033] Embodiment 2: Based on the first embodiment, the differences are as follows: Figure 1 As shown, it also includes a support frame 1, which is installed at the bottom of the heating tank 2.

[0034] Embodiment three: Based on the first embodiment, the differences are as follows: one side of the upper template 41 and the lower template 43 are connected by a hinge, and the other side of the upper template 41 and the lower template 43 are detachably connected by a buckle.

Claims

1. A cast XLPE cable main insulation recovery device, comprising a heating unit, an insulation pipe and a mold unit, wherein the heating unit comprises a heating tank for heating cross-linked polyethylene, and a detachable tank cover is arranged on the top of the heating tank; The tank cover is provided with an injection pressure interface, a pressure gauge and a thermometer, the lower part of the heating tank is provided with a three-way pipe, and the three-way pipe is provided with a valve; the characteristics are: The mold unit comprises an upper mold plate and a lower mold plate, the upper mold plate and the lower mold plate are detachably connected, and a cavity for accommodating the cable connector is formed between the upper mold plate and the lower mold plate; The interiors of the upper and lower templates are both hollow, and electric heating wires are installed in the inner cavities of the upper and lower templates respectively; A liquid inlet interface and at least one pressure relief valve are installed on the top of the upper template, and the bottom ends of the liquid inlet interface and the pressure relief valve are respectively connected to the cavity; The two ends of the insulation pipe are detachably connected to the liquid inlet interface and the three-way pipe respectively.

2. The cast XLPE cable main insulation recovery device according to claim 1, characterized in that: The valve is a manual valve or a solenoid valve.

3. The cast XLPE cable main insulation recovery device according to claim 1, characterized in that: The utility model also comprises a vibration table, on the table top of which two groups of support seats are installed, and reserved holes are opened on the support seats.

4. The cast XLPE cable main insulation recovery device according to claim 1, characterized in that: Also included is a support frame, which is mounted on the bottom of the heating tank.

5. The cast XLPE cable main insulation recovery device according to claim 3, characterized in that: The two ends of the upper template extend outward to form upper edges on both sides, and the two ends of the lower template extend outward to form lower edges on both sides. The upper edge and the lower edge are respectively provided with through holes connected up and down, and the same bolt is arranged in the upper and lower corresponding reserved holes and the two through holes.

6. The cast XLPE cable main insulation recovery device according to claim 3, characterized in that: One side of the upper template and the lower template is connected by a hinge, and the other side of the upper template and the lower template is detachably connected by a tower buckle.

7. The cast XLPE cable main insulation recovery device according to claim 5, characterized in that: The upper surface of the upper template and the lower surface of the lower template are respectively provided with a heat insulation layer, and both ends of the upper template and the lower template are respectively made of ceramic material.

8. The method for using the cast XLPE cable main insulation recovery device according to claim 5, characterized in that: The following steps are involved: S1. Use thermite reaction or welding to restore the cable core and polish it smooth; S2. The main insulation at both ends of the cable core is processed into a pencil head shape and polished smooth; S3, restore the inner semi-conductive layer of the cable; S4, placing the lower template on two sets of support seats; S5. Place the cable cores on both sides in the lower mold respectively, and buckle the upper mold onto the lower mold. Then, connect the upper mold, the lower mold and the support base with bolts. For three-core cables, three sets of mold units can be used to restore the main insulation of the three phases at the same time. S6. The solid cross-linked polyethylene liquid in the tank body is heated by a heating tank, the heating temperature is set to 260° C., and the pressure pipe of the pressurizing device is connected to the injection pressure interface; S7. When the center temperature of the cross-linked polyethylene liquid reaches 185°C, the pressurizing device, the vibration table and the two sets of electric heating wires are started one by one. The pressurizing device injects 3.5MPa high-pressure gas into the heating tank. At the same time, the valve is opened to allow the cross-linked polyethylene liquid in the heating tank to be injected between the upper mold plate and the lower mold plate through the insulation pipe. S8, two sets of electric heating wires heat the cross-linked polyethylene liquid in the upper template and the lower template respectively to prevent it from solidifying, and at the same time the vibration table works to discharge the bubbles in the cross-linked polyethylene liquid; S9. When the pressure relief valve automatically releases pressure and cross-linked polyethylene liquid flows out, close the pressurizing device and valve and stop injecting cross-linked polyethylene liquid; S10, turning off the vibration table and the two sets of electric heating wires to allow the cross-linked polyethylene liquid in the upper mold plate and the lower mold plate to cool automatically; S11. After the cross-linked polyethylene liquid is cooled, remove the bolts one by one, take down the upper template, and complete the main insulation restoration work at the connection between the two cables.

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