Core fixing pipe for manufacturing multi-core magnesium oxide mineral insulated cable

Abstract

The utility model provides a core fixing tube for manufacturing a multi-core magnesium oxide mineral insulated cable, which comprises an outer tube, a positioning pin and a plurality of inner tubes, the plurality of inner tubes and the positioning pin are welded and fixed together, the positioning pin is clamped in the outer tube, and a gap between the inner tube and the outer tube is used as an injection channel of magnesium oxide powder; the conductor of the magnesium oxide mineral insulated cable manufactured by the core fixing pipe does not shift, and the insulation thickness can be ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of insulated cables, in particular to a core fixing tube for manufacturing multi-core magnesium oxide mineral insulated cables. Background Art

[0002] There are many processing methods for magnesium oxide mineral insulated cables, the two main ones are the prefabricated magnesium oxide porcelain column method and the new magnesium oxide filling insulation welding copper tube method. There were about 15 prefabricated magnesium oxide porcelain column methods built before 2016 in China, and the construction was stopped after 2016, mainly because the length of the cables manufactured by this processing technology is limited. For example, the length of the finished cable of a single-core 150mm2 is about 150m, which is far from the 1000m of ordinary low-voltage cables. Therefore, it has gradually been replaced by the new magnesium oxide filling insulation welding copper tube production line. The new magnesium oxide filling insulation welding copper tube production line completes the filling, welding, rolling, annealing and other processes at one time. The equipment has a high degree of automation, and the length of the magnesium oxide mineral insulated cable produced by this equipment is not limited; but the cables produced by this processing technology have eccentricity, thin insulation thickness, and reduced compressive strength, which cannot meet the standard requirements. The important factor affecting eccentricity is the unstable positioning of the fixed core tube used on the equipment. The core tube used in multi-core mineral insulated cables produced by the new magnesium oxide filling insulation welding copper tube method is generally welded from stainless steel tubes with a diameter of 5mm to 17mm, a wall thickness of 0.5mm, and a length of about 3m. The 3m long, 0.5mm thick thin stainless steel tube is easy to bend and unstable. In addition, the welding speed is increased, the powder filling is not sufficient, and the insulation thickness does not meet the standard and the pressure resistance is unqualified. Utility Model Content

[0003] The utility model solves the problems of core deviation, thin insulation thickness and reduced compressive strength in the prior art production of magnesium oxide mineral insulated cables, and provides a core fixing tube for manufacturing multi-core magnesium oxide mineral insulated cables. The conductor of the magnesium oxide mineral insulated cable manufactured by the core fixing tube of the utility model is not core-deviant and the insulation thickness can be guaranteed.

[0004] In order to achieve the above objectives, the following technical solutions are proposed:

[0005] A core fixing tube for making a multi-core magnesium oxide mineral insulated cable comprises an outer tube, a positioning pin and a plurality of inner tubes. The plurality of inner tubes are fixed together by welding with the positioning pin, the positioning pin is clamped in the outer tube, and the gap between the inner tube and the outer tube serves as an injection channel for magnesium oxide powder.

[0006] The inner tube of the utility model is used to limit the conductor. The conductor passes through the inner tube so that the position of the conductor will not be offset when the magnesium oxide powder is injected. When the conductor and the magnesium oxide powder channel are stable, the wire core of the welded semi-finished cable will be stable, and the insulation thickness of the magnesium oxide powder can be guaranteed. The outer tube serves as a carrier of the wire core of the semi-finished cable. When the conductor and the magnesium oxide powder channel are stable, the copper tube welding equipment will wrap the copper tape on the outside of the outer tube, and then weld it into a copper tube. The copper tube and the semi-finished cable are extruded through the mobile device. The utility model improves the structure of the core-fixing tube on the basis of the existing magnesium oxide filling insulation welding copper tube method, so that the produced magnesium oxide mineral insulated cable will not have the core deviation phenomenon. The remaining copper tube welding equipment and mobile equipment are not within the scope of improvement of the utility model.

[0007] Preferably, the positioning pin includes a plurality of circular rings and a support section arranged on the outside of the circular rings, the outside of the support section is an arc surface, the radius of the arc surface is the same as the inner radius of the outer tube, the support section is clamped in the outer tube, the inner radius of the circular ring is the same as the outer radius of the inner tube, and the inner tube is welded and fixed in the circular ring.

[0008] The positioning pin of the utility model is provided with a circular ring for being welded and fixed with the inner tube, and the outer side of the circular ring is provided with a supporting section for being clamped and fixed with the outer tube.

[0009] Preferably, the circular ring is provided with a notch, and the size of the notch is smaller than one quarter of the circular ring.

[0010] Preferably, the width of the support section is at least half of the outer diameter of the ring. In order to increase the connection strength between the support section and the outer tube and reduce the pressure per unit area of ​​the outer tube, the utility model makes the width of the support section at least half of the outer diameter of the ring.

[0011] Preferably, the center distance D between two adjacent circular rings is the same, and the value of the center distance D depends on the thickness of the magnesium oxide insulation.

[0012] Preferably, an inner fixing sleeve is welded on the outer side of the inner tube, and an outer fixing sleeve is welded on the outer side of the outer tube.

[0013] Preferably, the inner tube and the outer tube are stainless steel tubes with a diameter of 5 mm to 17 mm, a wall thickness of 0.5 mm, and a length of about 3 m.

[0014] The beneficial effect of the utility model is that the utility model improves the structure of the core-fixing tube on the basis of the existing magnesium oxide filling insulation welding copper tube method, so that the produced magnesium oxide mineral insulated cable will not have the core deviation phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a schematic diagram of the inner tube structure of the utility model;

[0016] Figure 2 It is a schematic diagram of the outer tube structure of the utility model;

[0017] Figure 3 It is a schematic diagram of the positioning pin structure of the utility model;

[0018] Figure 4 It is a schematic diagram of the structure of the internal fixing sleeve of the utility model;

[0019] Figure 5 This is a schematic diagram of the structure of the external fixing sleeve of the utility model;

[0020] 1. Positioning pin; 2. Inner tube; 3. Inner fixing sleeve; 4. Outer tube; 5. Inner fixing sleeve; 11. Ring; 12. Support section. DETAILED DESCRIPTION

[0021] Example:

[0022] This embodiment provides a core fixing tube for making a multi-core magnesium oxide mineral insulated cable, comprising an outer tube 4, a positioning pin 1 and four inner tubes 2. The inner tube 2 and the outer tube 4 are stainless steel tubes with a diameter of 5 mm to 17 mm, a wall thickness of 0.5 mm and a length of about 3 m. An inner fixing sleeve 3 is welded to the outer side of the inner tube 2, and an outer fixing sleeve 5 is welded to the outer side of the outer tube 4.

[0023] refer to Figure 1 The main components of the inner tube of the core tube include: a positioning pin 1, an inner tube 2 and an inner fixing sleeve 3. The four inner tubes 2 are welded and fixed together with the positioning pin 1, the positioning pin 1 is clamped in the outer tube 4, and the gap between the inner tube 2 and the outer tube 4 serves as an injection channel for magnesium oxide powder.

[0024] refer to Figure 2 and Figure 5 The main components of the outer tube of the core tube include: outer tube 4 and outer fixing sleeve 5. The outer diameter of the outer tube 4 depends on the outer diameter and thickness of the copper tube to be welded. The gap between the inner tube 2 and the outer tube 4 is the injection channel for magnesium oxide powder. The size of the outer fixing sleeve 5 depends on the size left at the fixed position of the equipment. The material is generally 45# steel, and the inner hole is generally the outer diameter of the outer tube 4 + 0.2mm, which is convenient for the inner tube 2 to penetrate.

[0025] The positioning pin 1 includes four circular rings 11 and a support section 12 arranged on the outside of the circular rings 11. The outside of the support section 12 is an arc surface, and the radius of the arc surface is the same as the inner radius of the outer tube 4. The support section 12 is clamped in the outer tube 4. The inner radius of the circular ring 11 is the same as the outer radius of the inner tube 2, and the inner tube 2 is welded and fixed in the circular ring 11.

[0026] The positioning pin 1 of the utility model is provided with a circular ring 11 for being welded and fixed with the inner tube 2 , and a supporting section 12 for being clamped and fixed with the outer tube 4 is provided on the outer side of the circular ring 11 .

[0027] The ring 11 is provided with a notch, and the size of the notch is smaller than one quarter of the ring 11. Figure 3 , A is the center powder outlet, the size of the four gaps of the powder outlet cannot be larger than one-fourth of each ring, and three-fourths of the ring can be effectively connected with the stainless steel pipe during welding; B is the inner diameter of the stainless steel pipe of the outer sizing tube; C is the outer diameter of the stainless steel pipe of the inner sizing tube. Figure 4 The D value in the inner fixing sleeve 3 should be consistent with the D value in the positioning pin 1, and the D value depends on the thickness of the magnesium oxide insulation.

[0028] The width of the support section 12 is at least half of the outer diameter of the ring 11. In order to increase the connection strength between the support section 12 and the outer tube 4 and reduce the pressure per unit area of ​​the outer tube 4, the width of the support section 12 is at least half of the outer diameter of the ring 11.

[0029] The center distance D between two adjacent circular rings 11 is the same, and the value of the center distance D depends on the thickness of the magnesium oxide insulation.

[0030] The inner tube 2 of the utility model is used to limit the conductor. The conductor passes through the inner tube 2 so that the conductor position will not be offset when the magnesium oxide powder is injected. The positioning pin 1 can fix the inner tube of the core fixing tube as a whole in the copper tube welded by the copper strip, so that the copper rod passing through the stainless steel tube of the inner tube of the core fixing tube has a fixed position. The inner fixing sleeve 2 fastens the upper end of the inner tube of the core fixing tube to the equipment as a whole. After the upper and lower fixings are fixed, the position of the conductor is fixed. The outer fixing sleeve 5 connects the upper end of the outer tube of the core fixing tube to the equipment, and tightens the platform on the surface of the outer fixing sleeve with bolts, and the passage of the magnesium oxide powder is stabilized. When the conductor and the magnesium oxide powder passage are stable, the wire core of the welded semi-finished cable will be stable, and the insulation thickness of the magnesium oxide powder can be guaranteed. The outer tube 4 serves as a carrier of the wire core of the semi-finished cable. When the conductor and the magnesium oxide powder passage are stable, the copper tube welding equipment will wrap the copper strip around the outer side of the outer tube 4, and then weld it into a copper tube, and extrude the copper tube and the semi-finished cable through the mobile device. The utility model improves the structure of the core tube on the basis of the existing magnesium oxide filling insulation welding copper tube method, so that the produced magnesium oxide mineral insulated cable will not have the core deviation phenomenon. The other copper tube welding equipment and mobile equipment are not within the improvement scope of the utility model.

[0031] The production principle of this utility model is as follows:

[0032] 1. Use copper welding rods to weld the positioning pins, multiple inner tubes 2, positioning pins 1, and inner fixing sleeves 3. Specifically, first pass a stainless steel tube into one of the rings of the positioning pin 1, exposing about 10 mm, and mark the two ends of the inner tube 2 with the same number.

[0033] 2. Heat the positioning pin 1 with a welding gun, and then place the welding rod close to the gap between the positioning pin 1 and the inner tube 2 to allow the copper liquid to penetrate, and weld the other inner tubes 2 firmly in turn. After cooling, insert it into the outer tube 4. Do not twist the inner tube of the core tube during the insertion process, and ensure that the marked numbers are in the same direction after insertion.

[0034] 3. The welding method of the outer tube 4 is the same as above;

[0035] 4. Put on the rubber funnel of magnesium oxide powder.

[0036] 5. Insert the inner fixing sleeve 3 into the inner tube 2, leaving a distance of 10 mm exposed. The welding method is the same as above.

[0037] 6. After welding, the welding part needs to be carefully polished to remove the borax residue until the welding part is smooth and free of burrs.

Claims

1. A core tube for making a multi-core magnesium oxide mineral insulated cable, characterized in that: The invention comprises an outer tube (4), a positioning pin (1) and a plurality of inner tubes (2); the plurality of inner tubes (2) are fixed together with the positioning pin (1) by welding; the positioning pin (1) is clamped in the outer tube (4); and the gap between the inner tube (2) and the outer tube (4) serves as an injection channel for magnesium oxide powder.

2. The core fixing tube for making a multi-core magnesium oxide mineral insulated cable according to claim 1 is characterized in that: The positioning pin (1) comprises a plurality of circular rings (11) and a support section (12) arranged outside the circular rings (11); the outside of the support section (12) is an arc surface; the radius of the arc surface is the same as the inner radius of the outer tube (4); the support section (12) is clamped inside the outer tube (4); the inner radius of the circular ring (11) is the same as the outer radius of the inner tube (2); and the inner tube (2) is welded and fixed inside the circular ring (11).

3. The core fixing tube for making a multi-core magnesium oxide mineral insulated cable according to claim 2 is characterized in that: The circular ring (11) is provided with a notch, the size of which is smaller than one quarter of the circular ring (11).

4. The core fixing tube for making a multi-core magnesium oxide mineral insulated cable according to claim 2 is characterized in that: The width of the support section (12) is at least half of the outer diameter of the ring (11).

5. The core fixing tube for making a multi-core magnesium oxide mineral insulated cable according to claim 1 is characterized in that: The distance D between the centers of two adjacent circular rings (11) is the same.

6. The core-fixing tube for making a multi-core magnesium oxide mineral insulated cable according to claim 1 is characterized in that: An inner fixing sleeve (3) is welded to the outer side of the inner tube (2), and an outer fixing sleeve (5) is welded to the outer side of the outer tube (4).

7. A core fixing tube for making a multi-core magnesium oxide mineral insulated cable according to any one of claims 1 to 6, characterized in that: The inner tube (2) and the outer tube (4) are stainless steel tubes.

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