A mineral insulated prefabricated branch cable lifting hardware and a manufacturing method thereof

Abstract

The present invention discloses a mineral insulated prefabricated branch cable lifting hardware and a manufacturing method thereof, wherein the lifting hardware comprises a metal mesh sleeve (22) with a hanging ring, wherein an insulating flame retardant layer is arranged inside the metal mesh sleeve (22), wherein a trunk cable conductor (1) is arranged inside the insulating flame retardant layer, wherein the trunk cable conductor (1) is stripped from a trunk cable (7) and molded into a T-shaped cylinder, and a fire-resistant and anti-skid layer is arranged outside the unstripped trunk cable (7). The present invention solves the safety and quality defects that the prior art cannot meet the static load weight test requirements of the mineral insulated prefabricated branch cable lifting hardware, and the lifting hardware structure often falls off when the lifting hardware is hoisted to bear the load weight, and the lifting hardware cannot withstand the water immersion pressure test.

Description

Technical Field

[0001] The invention relates to the technical field of cable lifting hardware, and in particular to a mineral insulated prefabricated branch cable lifting hardware and a manufacturing method thereof. Background Art

[0002] Welded corrugated copper tube sheathed mineral insulated cable (hereinafter referred to as mineral insulated cable or cable) has been introduced into my country from abroad for more than ten years. It is now widely used in fire protection power supply and distribution lines of important projects such as urban high-rise buildings, large complexes, stadiums, museums, hospitals, etc., and in some fire protection power supply and distribution branch lines, mineral insulated prefabricated branch cables are increasingly used.

[0003] Since the mineral insulated prefabricated branch cable has a copper conductor and a layer of welded corrugated copper tube sheath (hereinafter referred to as copper sheath) outside the cable core, compared with the traditional plastic insulated ordinary cable, the weight of the mineral insulated cable is at least 1.5 times or more of the ordinary cable. At the same time, the main cable of the mineral insulated prefabricated branch cable is also connected to the branch cable, especially the single-core mineral insulated prefabricated branch cable, the cross-sectional area of ​​the main cable conductor can reach 185~300mm 2 , the weight of the cable system can reach tons, which makes laying and installation extremely difficult. If vertical laying is required, the copper sheath of the mineral insulated prefabricated branch cable is cut into sections at the branch connector and then connected by the branch connector metal box (see Figure 1 ), cannot withstand any axial tension or gravity at all, so when vertically lifting the mineral insulated prefabricated branch cable trunk cable, the existing lifting hardware can no longer guarantee the cable quality and lifting safety, which has become a defect of the prior art. Summary of the invention

[0004] In order to improve the convenience, safety and reliability of lifting and hoisting of mineral insulated prefabricated branch cables during vertical laying and fill the gap in the prior art, the present invention proposes a mineral insulated prefabricated branch cable lifting hardware and a manufacturing method thereof.

[0005] The present invention is implemented by adopting the following technical scheme: a mineral insulated prefabricated branch cable lifting fitting, comprising a metal mesh sleeve with a hanging ring, an insulating flame retardant layer is arranged inside the metal mesh sleeve with a hanging ring, a main cable conductor is arranged inside the insulating flame retardant layer, the main cable conductor is stripped from the main cable and molded into a T-shaped cylinder, and a fire-resistant and anti-slip layer is arranged outside the unstripped main cable.

[0006] Furthermore, the insulating flame-retardant layer comprises a fire-resistant sealed insulating sleeve, a fixed sleeve is arranged inside the fire-resistant sealed insulating sleeve, and the fixed sleeve is used to wrap the upper end of the T-shaped cylinder.

[0007] Furthermore, an insulating ring is provided in the fire-resistant sealing insulating sleeve, and the insulating ring is used to wrap the lower end of the T-shaped cylinder, and a part of the lower end of the T-shaped cylinder is provided with a main cable mineral insulation layer.

[0008] Furthermore, the fire-resistant and anti-slip layer includes a highly flame-retardant heat-shrinkable tube, which is arranged on the outside of the unstripped trunk cable and connected to the insulating ring.

[0009] Furthermore, a highly flame-retardant heat-shrinkable sealing cap is arranged outside the metal mesh sleeve with a hanging ring.

[0010] Furthermore, a stainless steel locking hoop is arranged outside the highly flame retardant heat shrinkable sealing cap, and a fire-resistant anti-skid pad is arranged between the stainless steel locking hoop and the highly flame retardant heat shrinkable sealing cap.

[0011] Furthermore, the main cable conductor is molded into a T-shaped cylinder by a hydraulic device.

[0012] Furthermore, the hydraulic device includes a symmetrically arranged left mold mechanism and a right mold mechanism, the left mold mechanism includes a left mold pressure cylinder and a left mold, and the right mold mechanism includes a right mold pressure cylinder and a right mold.

[0013] Furthermore, the hydraulic device also includes an upper mold mechanism, which includes an upper mold pressure cylinder and an upper mold. Through the joint action of the left mold, the right mold and the upper mold, the main cable conductor is molded into a T-shaped cylinder.

[0014] A method for manufacturing a mineral insulated prefabricated branch cable lifting fitting comprises the following steps:

[0015] S1: stripping the main cable conductor at the end of the main cable;

[0016] S2: Set the insulating ring at the bottom of the stripped main cable conductor to completely isolate the main cable conductor from the main cable sheath;

[0017] S3: Place the exposed main cable conductor after stripping into a hydraulic device for molding to form a T-shaped cylinder;

[0018] S4: Use highly flame-retardant heat shrink tubing to seal the main cable sheath;

[0019] S5: Use a fixing sleeve to fasten the T-shaped cylinder;

[0020] S6: Install the fire-resistant sealing insulating sleeve on the outside of the fixing sleeve and the insulating ring;

[0021] S7: After the metal mesh sleeve with hanging ring is stretched tightly, it is put on the outside of the fire-resistant sealing insulation sleeve and the high flame retardant heat shrinkable sleeve, and sealed with a high flame retardant heat shrinkable sealing cap.

[0022] The beneficial effects of the present invention are as follows: the present invention solves the safety and quality defects that the prior art cannot meet the static load weight test requirements of the mineral insulated prefabricated branch cable lifting hardware, and the lifting hardware structure often falls off when lifting to bear the load weight, making it unable to withstand the water immersion pressure test. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0024] Figure 1 It is a schematic diagram of the branch connector structure of the top of the mineral insulated prefabricated branch cable and its adjacent trunk cable and branch cable;

[0025] Figure 2 It is a schematic diagram of the main cable structure after stripping;

[0026] Figure 3 It is a schematic diagram of the insulating ring structure;

[0027] Figure 4 This is a schematic diagram of the trunk cable structure after the insulation ring is installed;

[0028] Figure 5 It is a schematic diagram of the structure of the hydraulic device;

[0029] Figure 6 It is a schematic diagram of the structure after the hydraulic device is compressed;

[0030] Figure 7 It is a front view of the fixed sleeve;

[0031] Figure 8 It is a top view of the fixed sleeve;

[0032] Fig. 9 It is a schematic diagram of the structure of the fire-resistant sealing insulation sleeve;

[0033] Fig.10 This is a schematic diagram of the structure of a metal mesh sleeve with a hanging ring;

[0034] Fig.11 To enhance the schematic diagram of the hardware structure;

[0035] In the figure, 1-main cable conductor, 2-main cable mineral insulation layer, 3-main cable sheath, 4-branch connector shell, 5-fire-resistant filler, 6-branch connector, 7-main cable, 8-branch cable, 9-insulating ring, 10-press frame, 11-left mold pressure cylinder, 12-left mold pressure cylinder fixing block, 13-left mold, 14-upper mold pressure cylinder fixing bracket, 15-upper mold pressure cylinder, 16-upper mold, 17-right mold, 18-right mold pressure cylinder fixing block, 19-right mold pressure cylinder, 20-fixing sleeve, 21-fire-resistant sealing insulation sleeve, 22-metal mesh sleeve with hanging ring, 23-high flame retardant heat shrinkable sleeve, 24-fire resistant anti-slip pad, 25-stainless steel locking hoop, 26-high flame retardant heat shrinkable sealing cap. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0038] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0039] Prefabricated branch cables are assembled cables (systems) that are composed of a trunk cable and multiple branch cables (spaced at a certain distance) connected together and are used in trunk branch line systems. Figure 1 It is a diagram showing the branch connector structure of the top of the mineral insulated prefabricated branch cable and its adjacent trunk cable and branch cable. In the figure, the trunk cable 7 is composed of the trunk cable conductor 1, the trunk cable mineral insulation layer 2 and the trunk cable sheath 3 from the inside to the outside, wherein the trunk cable 7 branches out the branch cable 8 through the branch connector 6, and a refractory filler 5 is also provided at the connection between the trunk cable 7 and the branch cable 8, and a branch connector shell 4 is also provided outside the refractory filler 5. It is well known to those skilled in the art that the lifting hardware required for lifting during cable laying and installation is installed on the top of the trunk cable. Since the outer sheath of the mineral insulated prefabricated branch cable is copper, and there are multiple branch cables connected to the trunk cable, the weight of the system is 1.5 to 2 times that of ordinary cables or ordinary prefabricated branch cables, so the traditional prefabricated branch cable lifting hardware (load bearing capacity) can no longer be used on mineral insulated prefabricated branch cables.

[0040] Since the copper sheath of the main cable of the mineral insulated prefabricated branch cable is cut off at the branch connector (connected by the copper shell of the branch connector), it cannot withstand axial tension and load. That is to say, when the cable is lifted, the system load borne by the lifting fittings installed on the main cable of the mineral insulated branch cable can only be borne by the main cable conductor. From the technical requirements, even during lifting, the cable conductor at the lifting fittings installed on the top of the main cable must have reliable and excellent electrical insulation performance and waterproof and moisture-proof performance from the outside world (including the lifting fittings).

[0041] To this end, the present invention provides a mineral insulated prefabricated branch cable lifting hardware, see Figures 2 to 11 The lifting hardware includes a metal mesh sleeve 22 with a hanging ring, and an insulating flame-retardant layer is arranged in the metal mesh sleeve 22 with a hanging ring. A main cable conductor 1 is arranged in the insulating flame-retardant layer. The main cable conductor 1 is stripped from the main cable 7 and molded into a T-shaped cylinder. The unstripped main cable 7 is provided with a fire-resistant and anti-slip layer on the outside. The insulating flame-retardant layer includes a fire-resistant sealed insulating sleeve 21, and a fixed sleeve 20 is arranged in the fire-resistant sealed insulating sleeve 21. The fixed sleeve 20 is used to wrap the upper end of the T-shaped cylinder. A (high-strength) insulating ring 9 is also arranged in the fire-resistant sealed insulating sleeve 21. The insulating ring 9 is used to wrap the lower end of the T-shaped cylinder. A part of the lower end of the T-shaped cylinder is provided with a main cable mineral insulation layer 2.

[0042] In this embodiment, the fire-resistant and anti-slip layer includes a highly flame-retardant heat-shrinkable sleeve 23, which is arranged on the outside of the unstripped trunk cable 7 and connected to the insulating ring 9. A highly flame-retardant heat-shrinkable sealing cap 26 is arranged outside the metal mesh sleeve 22 with a hanging ring, and a stainless steel locking hoop 25 is arranged outside the highly flame-retardant heat-shrinkable sealing cap 26. A fire-resistant and anti-slip pad 24 is also arranged between the stainless steel locking hoop 25 and the highly flame-retardant heat-shrinkable sealing cap 26.

[0043] In this embodiment, the main cable conductor 1 is molded into a T-shaped cylinder by a hydraulic device, and the hydraulic device includes a left mold mechanism and a right mold mechanism that are symmetrically arranged. The left mold mechanism includes a left mold pressure cylinder 11 and a left mold 13, and a left mold pressure cylinder fixing block 12 is also arranged between the left mold pressure cylinder 11 and the left mold 13; the right mold mechanism includes a right mold pressure cylinder 19 and a right mold 17, and a right mold pressure cylinder fixing block 18 is also arranged between the right mold pressure cylinder 19 and the right mold 17, wherein the left mold 13 and the right mold 13 are connected to each other. The molds 17 are all semi-cylindrical forming molds; the hydraulic device also includes an upper mold mechanism, which includes an upper mold pressure cylinder 15 and an upper mold 16, and an upper mold pressure cylinder fixing bracket 14 is also arranged between the upper mold pressure cylinder 15 and the upper mold 16. The hydraulic devices are all arranged on the press frame 10, and the left mold 13, the right mold 17 and the upper mold 16 are driven by the left mold pressure cylinder 11, the right mold pressure cylinder 19 and the upper mold pressure cylinder 15 respectively to move together, so as to realize the molding of the trunk cable conductor 1 into a T-shaped cylinder.

[0044] A method for manufacturing a mineral insulated prefabricated branch cable lifting fitting comprises the following steps:

[0045] Step 1: First, strip the conductor at the end of the trunk cable 7. Figure 2 The length L0+L1 is shown, where L0 is the given length of 10 mm in the process, and L1 is the length of the conductor required for subsequent cold pressing of the end conductor into a "T"-shaped cylinder. L1 is determined by formula (1):

[0046] (1)

[0047] Where d is the diameter of the main cable conductor, unit: mm; D is the diameter of the cold-pressed "T" cylinder (see Figure 6 As shown), D=d+2k1 (the value of k1 is shown in Table 1), unit: mm; L2 is the height of the "T"-shaped cylinder formed by cold pressing (see Figure 6 As shown in Table 1, L2 values ​​are in mm; k0 is the compression coefficient, which ranges from 0.88 to 0.92.

[0048] Table 1 Values ​​of k1 and L2 (unit: mm)

[0049] .

[0050] Step 2: Figure 3 The insulating ring 9 shown is inserted into the bottom of the stripped main cable conductor 1 (see Figure 4 As shown), it completely isolates the main cable conductor 1 and the main cable sheath 3.

[0051] Step 3: Place the exposed main cable conductor 1 into a hydraulic device (such as Figure 5The left and right semi-cylindrical pressure molds are combined to tightly fix the main cable conductor 1.

[0052] Step 4: Operate the hydraulic device to Figure 5 The bulk main cable conductor 1 is formed by cold pressing under a given pressure (F=SP, F is pressure, S is area, P is pressure, P≥3000MPa) of the mold. Figure 6 The role of cold pressing is to make the original single wire in the "T"-shaped cylinder produce strong plastic deformation, the original small amount of oxide film on the surface is destroyed and squeezed out, so that a new metallurgical combination is formed between the original single wire interfaces, making it have excellent mechanical strength and rigidity. Figure 6 In the process, the diameter of the "T"-shaped cylinder formed by molding is D (D=d+2k1) and the height is L2. After this step is completed, the main cable lifting hardware installation stage will begin.

[0053] Step 5: After the end of the trunk cable conductor 1 is cold-pressed into a "T"-shaped cylinder and demoulded, a highly flame-retardant heat-shrinkable sleeve 23 is used to seal the trunk cable sheath 3 at the end of the trunk cable 7.

[0054] Step 6: Use Figure 7 , Figure 8 The (copper) fixing sleeve 20 shown fastens the "T" shaped cylinder to increase the structural stability of the lifting hardware.

[0055] Step 7: Fig. 9 The fire-resistant sealing insulating sleeve 21 shown is firmly installed outside the fixing sleeve 20 and the insulating ring 9, so that the lifting hardware is both fastened and has excellent insulating performance.

[0056] Step 8: Fig.10 The metal mesh sleeve 22 with hanging ring is stretched tightly and sleeved on the lifting hardware fire-resistant sealing insulation sleeve 21 and the high flame retardant heat shrink sleeve 23, and is sealed with a high flame retardant heat shrink sealing cap 26 outside the metal mesh sleeve 22 with hanging ring. Fig.11 The hanging ring on the upper end of the middle band hanging ring metal net cover 22 becomes the hanging ring of the trunk cable when lifting the prefabricated branch cable. For guaranteeing that the metal net does not slip when lifting, it is fastened firmly with stainless steel locking hoop 25 and fire-resistant anti-skid pad 24 at three places of lifting hardware lower end.

[0057] The technical requirements for trunk cable lifting fittings in the relevant product standards for prefabricated branch cables are shown in Table 2 below.

[0058] Table 2 Technical requirements for prefabricated branch cable lifting fittings

[0059] .

[0060] The technical methods and measures adopted in the research and development of the mineral insulated prefabricated branch cable lifting hardware of the present invention are to solve the safety and quality defects that the existing technology cannot meet the static load weight test requirements of the mineral insulated prefabricated branch cable lifting hardware, and the lifting hardware structure often falls off when lifting to bear the load weight, and it cannot withstand the water immersion pressure test. When the mineral insulated prefabricated branch cable of the present invention is subjected to the static load test, the "T"-shaped round standard conductor formed by cold pressing in the lifting hardware structure bears the load weight, ensuring the reliability and safety of the mineral insulated prefabricated branch cable of the present invention in bearing the static load weight. At the same time, the copper conductor in the lifting hardware of the mineral insulated prefabricated branch cable of the present invention and the copper fixing sleeve connected to the conductor are respectively sealed and isolated by a special high-strength insulating ring and a high-strength fire-resistant sealing sleeve, and are sealed on the outside of the lifting hardware by a high-flame-retardant heat-shrinkable sleeve and a high-flame-retardant heat-shrinkable sealing cap, respectively, so that it has excellent waterproof and moisture-proof sealing performance and insulating dielectric properties.

[0061] The technical performance of the mineral insulated prefabricated branch cable lifting hardware of the present invention has been tested by a certain testing center and all meet the relevant product technical requirements. The specific data are as follows:

[0062] Table 3-1 Test results of the technical performance of the lifting hardware of the present invention

[0063] .

[0064] Table 3-2 Test results of the technical performance of the hardware of the present invention

[0065] .

[0066] Compared with the prior art, the technical advantages of the present invention are as follows:

[0067] Prior art 1: utility model patent (CN201868831U); Prior art 2: utility model patent (CN201260053Y). The structural principles of prior art 1 and 2 are consistent, and both are lifting fittings suitable for ordinary plastic insulated prefabricated branch cables, but not suitable for the mineral insulated prefabricated branch cables of the present invention. The main reason is that this type of lifting fittings uses expansion nails on the end face of the conductor to expand the conductor of the main cable and tighten it with the clamping piece (ring), and the clamping piece is connected to the outer insulating waterproof layer and the metal connecting sleeve of the installation ring. When this type of lifting fittings lifts the prefabricated branch cable (system), the load weight is mainly borne by the friction between the fastener and the swollen conductor. Whether it is the load weight or the safety and reliability, it is not comparable to the lifting fittings of the present invention.

[0068] It should be noted that, for the above embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification belong to preferred embodiments, and the actions involved are not necessarily required by the present application.

[0069] The above embodiments describe the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the changes and modifications made by those skilled in the art shall be within the scope of protection of the appended claims of the present invention without departing from the spirit and scope of the present invention.

Claims

1. A mineral insulated prefabricated branch cable lifting fitting, characterized in that: It comprises a metal mesh sleeve (22) with a hanging ring, wherein an insulating flame-retardant layer is arranged inside the metal mesh sleeve (22), wherein a trunk cable conductor (1) is arranged inside the insulating flame-retardant layer, wherein the trunk cable conductor (1) is stripped from a trunk cable (7) and molded into a T-shaped cylinder, and a fire-resistant and anti-slip layer is arranged outside the trunk cable (7) that has not been stripped; The insulating flame-retardant layer comprises a fire-resistant sealed insulating sleeve (21), a fixing sleeve (20) is arranged inside the fire-resistant sealed insulating sleeve (21), and the fixing sleeve (20) is used to wrap the upper end of the T-shaped cylinder; An insulating ring (9) is also provided inside the fire-resistant sealing insulating sleeve (21), and the insulating ring (9) is used to wrap the lower end of the T-shaped cylinder, and a portion of the lower end of the T-shaped cylinder is provided with a trunk cable mineral insulation layer (2).

2. A mineral insulated prefabricated branch cable lifting fitting as claimed in claim 1, characterized in that: The fire-resistant and anti-slip layer comprises a highly flame-retardant heat-shrinkable tube (23), which is arranged on the outside of the unstripped trunk cable (7) and connected to the insulating ring (9).

3. A mineral insulated prefabricated branch cable lifting fitting as claimed in claim 2, characterized in that: A highly flame-retardant heat-shrinkable sealing cap (26) is arranged outside the metal mesh sleeve (22) with a hanging ring.

4. A mineral insulated prefabricated branch cable lifting fitting as claimed in claim 3, characterized in that: A stainless steel locking hoop (25) is arranged inside the highly flame-retardant heat-shrinkable sealing cap (26), and a fire-resistant anti-skid pad (24) is also arranged between the stainless steel locking hoop (25) and the metal mesh sleeve (22) with a hanging ring.

5. The mineral insulated prefabricated branch cable lifting fitting according to claim 1, characterized in that: The main cable conductor (1) is molded into a T-shaped cylinder by a hydraulic device.

6. A mineral insulated prefabricated branch cable lifting fitting as claimed in claim 5, characterized in that: The hydraulic device comprises a left mold mechanism and a right mold mechanism which are symmetrically arranged, the left mold mechanism comprising a left mold pressure cylinder (11) and a left mold (13), and the right mold mechanism comprising a right mold pressure cylinder (19) and a right mold (17).

7. A mineral insulated prefabricated branch cable lifting fitting as claimed in claim 6, characterized in that: The hydraulic device also includes an upper die mechanism, which includes an upper die pressure cylinder (15) and an upper die (16). The left die (13), the right die (17) and the upper die (16) work together to mold the main cable conductor (1) into a T-shaped cylinder.

8. A method for manufacturing a mineral insulated prefabricated branch cable lifting fitting, used to manufacture a mineral insulated prefabricated branch cable lifting fitting as claimed in any one of claims 1 to 7, characterized in that: The steps include: S1: stripping the trunk cable conductor (1) at the end of the trunk cable (7); S2: placing an insulating ring (9) at the bottom of the stripped main cable conductor (1) to completely isolate the main cable conductor (1) from the main cable sheath (3); S3: placing the exposed main cable conductor (1) after stripping into a hydraulic device for molding to form a T-shaped cylinder; S4: Use a highly flame-retardant heat shrink tubing (23) to seal the main cable sheath (3); S5: Using a fixing sleeve (20) to fasten the T-shaped cylinder; S6: Installing the fire-resistant sealing insulating sleeve (21) on the outside of the fixing sleeve (20) and the insulating ring (9); S7: After the metal mesh sleeve with hanging ring (22) is stretched tightly, it is put on the outside of the fire-resistant sealing insulation sleeve (21) and the high flame retardant heat shrink sleeve (23), and sealed by the high flame retardant heat shrink sealing cap (26).

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