An insulating shielding tube without inner mold preparation and a preparation method thereof

Abstract

The invention discloses an insulating shielding tube and a preparation method thereof which do not require inner mold preparation, and belongs to the technical field of shielding tubes. It includes an inner support frame, an insulating jacket coaxially arranged outside the inner support frame, and epoxy resin filling therebetween; the inner support frame includes a voltage-equalizing tube in the middle, two flanges at both ends, and two insulating support tubes between the voltage-equalizing tube and the flange, the voltage-equalizing tube, the insulating support tube and the flange are coaxially arranged and sealed with each other by adhesive seal or sealing ring, the voltage-equalizing tube and the insulating support tube are wrapped with a crepe paper functional layer and a copper tape functional layer, the two ends of the insulating jacket are sleeved and fastened on the flanges on the corresponding sides to form an annular insulating filling cavity with the inner support frame and the flange, a plurality of flange holes are provided on the flange, and only some of the flange holes are connected to the insulating filling cavity to form a casting functional hole, the epoxy resin material enters the insulating filling cavity through the casting functional hole to form epoxy resin filling and impregnates the crepe paper functional layer to form a frame, and the insulating jacket includes a heat shrinkable insulating tube layer.

Description

Technical Field

[0001] The invention belongs to the technical field of shielding tubes, and in particular relates to an insulating shielding tube that does not require inner mold preparation and a preparation method thereof. Background Art

[0002] With the extensive application of tubular busbars, especially the application of insulated tubular busbars, higher and higher requirements are placed on the methods and requirements of intermediate connections. According to the requirements of busbar connection, the busbar intermediate joints must be reliably connected and the insulation performance must meet the standard requirements. At the same time, in order to meet the maintenance and inspection requirements of busbar insulating joints, they need to be removable.

[0003] Existing shielding tubes are manufactured using steel molds as molds, such as Figure 1-3 As shown, the flange is bonded after demolding. However, there are many problems in the prior art, such as high mold costs, demolding after manufacturing is completed (usually a jack or a special demolding tool is required for demolding), the demolding process is difficult and can easily cause insulation damage, and the flange needs to be fixed and bonded after demolding. The flange bonding process can easily cause loose fixation and poor sealing. In addition, in the prior art, it is necessary to design inner molds of corresponding specifications for products of different specifications, which has the disadvantages of high cost and long design time; at the same time, in the prior art, the sealing requirements for the inner mold are high, and a demolding angle is also set on the product. Summary of the invention

[0004] In order to solve the above problems, the embodiment of the present invention provides an insulating shielding tube and a preparation method thereof that does not require an inner mold. The insulating shielding tube can be prepared without an inner mold, which saves time and effort and is convenient for obtaining products of various specifications. At the same time, some flange holes have the function of both flange holes and casting holes. A combination of an equalizing tube, an insulating support tube and a flange is used, and a corrugated paper functional layer and a copper tape functional layer are wrapped around the outside, so that it can withstand the casting pressure while having the functions of insulation and shielding. The technical scheme is as follows:

[0005] On the one hand, an embodiment of the present invention provides an insulating shielding tube that does not require inner mold preparation, including an inner support skeleton 1, an insulating jacket 2 coaxially arranged outside the inner support skeleton 1, and epoxy resin filling 3 therebetween; the inner support skeleton 1 includes a voltage-equalizing tube 4 in the middle, two flanges 5 at both ends, and two insulating support tubes 6 between the voltage-equalizing tube 4 and the flange 5, the voltage-equalizing tube 4, the insulating support tube 6 and the flange 5 are all coaxially arranged and sealed with each other by adhesive sealing or sealing rings, the voltage-equalizing tube 4 and the insulating support tube 6 are wrapped with a corrugated paper functional layer and a copper tape functional layer, the two ends of the insulating jacket 2 are sleeved and fastened on the flange 5 on the corresponding side to form an annular insulating filling cavity with the inner support skeleton 1 and the flange 5, the flange 5 is provided with a plurality of flange holes and only some of the flange holes are connected to the insulating filling cavity to form a casting functional hole 7, the epoxy resin material enters the insulating filling cavity through the casting functional hole 7 to form the epoxy resin filling 3 and impregnates the corrugated paper functional layer to form a skeleton, and the insulating jacket 2 includes a heat shrinkable insulating tube layer.

[0006] The insulating support tube 6 in the embodiment of the present invention is an epoxy resin tube or a polytetrafluoroethylene tube, and its thickness is 1-5 mm; the thickness of the heat shrinkable insulating tube layer is 1-3 mm.

[0007] The crepe paper functional layer in the embodiment of the present invention is formed by wrapping crepe paper with shielding and insulating functions, and its thickness is 0.1-0.5 mm.

[0008] Among them, the voltage-equalizing tube 4 in the embodiment of the present invention is a non-magnetic metal tube, and annular bosses are coaxially provided at both ends of the tube; the annular boss is inserted into the insulating support tube 6 to realize the connection between the voltage-equalizing tube 4 and the insulating support tube 6, and its length is 10-30mm; the outer diameter of the voltage-equalizing tube 4 is consistent with the outer diameter of the insulating support tube 6, and its inner diameter is 0.5-2.0mm smaller than the inner diameter of the insulating support tube 6.

[0009] Furthermore, the flange 5 in the embodiment of the present invention is a non-magnetic metal flange or a high-strength non-metallic flange, which is an annular columnar structure that matches the size of the insulating sleeve 2, and its inner hole is flush with the inner wall of the insulating support tube 6 and is coaxially provided with a step hole for inserting the insulating support tube 6, and a plurality of outer annular grooves 9 are coaxially provided on its outer peripheral surface; the insulating support tube 6 is inserted in the step hole to realize the connection between the insulating support tube 6 and the flange 5.

[0010] Preferably, two pouring function holes 7 are symmetrically provided on the flange 5 in the embodiment of the present invention, and the flanges 5 at both ends of the inner support frame 1 are symmetrically arranged.

[0011] Among them, the flange holes in the embodiments of the present invention are all threaded holes that penetrate the flange 5 and are arranged axially along the inner support frame 1. The inner ends of other flange holes except the pouring function hole 7 are provided with plugs 10 to close them. The pouring function hole 7 can be threadedly connected with the pouring head 11.

[0012] On the other hand, an embodiment of the present invention further provides a method for preparing an insulating shielding cylinder without inner mold preparation, comprising the following steps:

[0013] (1) Two insulating support tubes 6 are sleeved on the annular bosses at both ends of the equalizing tube 4, and flanges 5 are sleeved on the other ends of the two insulating support tubes 6. The equalizing tube 4, the insulating support tube 6 and the flanges 5 are sealed by adhesive or sealing rings to form an internal support skeleton 1, and the inner ends of some flange holes are closed, while the unclosed flange holes are used as casting function holes 7;

[0014] (2) A tensioning mold 12 is arranged on the inner support frame 1 to tighten and fix the pressure equalizing tube 4, the insulating support tube 6 and the flange 5 together along the axial direction;

[0015] (3) Wrapping the crepe paper and copper tape with shielding function and insulation function around the equalizing tube 4 and the insulating support tube 6 from the inside to the outside in sequence to form a crepe paper functional layer and a copper tape functional layer respectively;

[0016] (4) a heat-shrinkable insulating tube is arranged outside the inner support frame 1 to form an insulating jacket 2, and both ends of the heat-shrinkable insulating tube are sleeved on the outer wall of the flange 5 on the corresponding side and fixed by gluing;

[0017] (5) A clamping structure 13 is provided outside the insulating jacket 2 and located at the flange 5 to fasten the insulating jacket 2 to the flange 5;

[0018] (6) Wrapping a cloth tape around the outside of the insulating jacket 2 to form a cast reinforcement layer 19;

[0019] (7) Under vacuum conditions, epoxy resin material is poured into the pouring function hole 7 of the flange 5 on one side, the pouring temperature is 110-150° C., and the pouring pressure is 0.1-0.3 MPa; the material is discharged from the pouring function hole 7 of the flange 5 on the other side, and the pouring is stopped when there are no bubbles in the discharged material;

[0020] (8) After cooling and molding, the tensioning mold 12, the clamping structure 13 and the pouring reinforcement layer 19 are removed to obtain the product.

[0021] Among them, the tensioning mold 12 in the embodiment of the present invention includes a screw rod 14 and two top plates 15 at both ends thereof, wherein the screw rod 14 is arranged along the axis of the inner support frame 1; the top plate 15 is arranged perpendicular to the screw rod 14, and its two ends are pressed on the end surface of the flange 5 and are respectively fixedly connected to two symmetrically arranged flange holes to center the screw rod 14, and a buffer pad 16 is provided on the inner side thereof; one of the top plates 15 is fixed to the screw rod 14 by two nuts 17 on its inner and outer sides, and the other top plate 15 can be adjusted along the position of the screw rod 14 by a nut 17 on its outer side, and a through hole for the screw rod 14 to pass through is provided in the middle of the top plate 15.

[0022] In step (5) of the embodiment of the present invention, the thickness of the cast reinforcement layer 19 is 1-3 mm and it is formed by wrapping a woven cloth tape with a thickness of 0.1-0.3 mm.

[0023] The technical solution provided by the embodiment of the present invention has the following beneficial effects: the embodiment of the present invention provides an insulating shielding tube and a preparation method thereof that does not require an inner mold to prepare, and the insulating shielding tube can be prepared without an inner mold, which saves time and effort and is convenient for obtaining products of various specifications. At the same time, some flange holes have the functions of flange holes and casting holes, and there is no need to bond the flange after demolding, and the flange has good stability; a combination of an equalizing tube, an insulating support tube and a flange is used, and a corrugated paper functional layer and a copper tape functional layer are wrapped around the outside, so that it can withstand the casting pressure under the premise of having functions such as insulation and shielding. The obtained insulating shielding tube has good sealing performance and can also meet the electrical performance of the insulating shielding tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the combination of an insulating shielding tube and an inner mold in the prior art;

[0025] Figure 2 It is a schematic diagram of the structure of the insulating shielding tube in the prior art when demoulding;

[0026] Figure 3 It is a structural schematic diagram of a flange of an insulating shielding tube in the prior art;

[0027] Figure 4 It is a structural schematic diagram of the combination of the inner support frame and the tensioning mold provided by an embodiment of the present invention;

[0028] Figure 5 It is a structural schematic diagram of the combination of the inner support frame and the insulating jacket provided in an embodiment of the present invention;

[0029] Figure 6 It is a schematic structural diagram of the insulating shielding tube provided by an embodiment of the present invention during casting;

[0030] Figure 7 It is a schematic structural diagram of an insulating shielding tube provided by an embodiment of the present invention;

[0031] Figure 8 It is a schematic structural diagram of a flange of an insulating shielding cylinder provided in an embodiment of the present invention;

[0032] Fig. 9 yes Figure 4 A partial enlarged view of

[0033] Fig.10 This is a usage status diagram of the insulating shielding tube provided by an embodiment of the present invention.

[0034] In the figure: 1 inner support frame, 2 insulating jacket, 3 epoxy resin filling, 4 equalizing tube, 5 flange, 6 insulating support tube, 7 pouring function hole, 8 ordinary flange hole, 9 outer ring groove, 10 plug, 11 pouring head, 12 tensioning mold, 13 clamping structure, 14 screw, 15 top plate, 16 buffer pad, 17 nut, 18 inner ring groove, 19 pouring reinforcement layer. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0036] Example 1

[0037] See also Figure 4-9 The embodiment of the present invention provides an insulating shielding tube that does not require inner mold preparation, including an inner support skeleton 1, an insulating jacket 2 coaxially arranged outside the inner support skeleton 1, and epoxy resin filling 3 therebetween. The inner support skeleton 1 includes a voltage-equalizing tube 4 in the middle, two flanges 5 at both ends, and two insulating support tubes 6 between the voltage-equalizing tube 4 and the flange 5. The voltage-equalizing tube 4, the insulating support tube 6, and the flange 5 are coaxially arranged and sealed with each other by adhesive sealing or sealing rings to ensure sealing. The voltage-equalizing tube 4 and the insulating support tube 6 are wrapped with a corrugated paper functional layer (not shown) and a copper tape functional layer (not shown); the corrugated paper functional layer has four functions: the first is insulation, the second is shielding, the third is skeleton (after impregnation with epoxy resin), and the fourth is sealing; the copper tape functional layer is formed by wrapping copper tape and has a grounding function; the inner support skeleton 1, the corrugated paper functional layer, and the copper tape functional layer together form an inner mold. The two ends of the insulating jacket 2 are sleeved and fastened on the outer wall of the flange 5 on the corresponding side to form a ring-shaped insulating filling cavity with the inner support skeleton 1 and the flange 5. The flange 5 is provided with a plurality of flange holes and only some of the flange holes are connected to the insulation filling cavity to form a pouring function hole 7; the flange holes are arranged along the axial direction of the inner support frame 1, and include a pouring function hole 7 and an ordinary flange hole 8; the pouring function hole 7 simultaneously functions as a pouring hole and a flange hole, and the inner end of the ordinary flange hole 8 is closed and only functions as a flange hole. The epoxy resin material enters the insulation filling cavity through the pouring function hole 7 to form the epoxy resin filling 3 and impregnates the crepe paper functional layer to form a frame. The insulating jacket 2 includes a heat shrinkable insulation tube layer, and both ends of the heat shrinkable insulation tube layer are specifically flush with the outer end surface of the flange 5. The heat shrinkable insulation tube layer is a conventional heat shrinkable insulation tube, which needs to be wrapped with a pouring reinforcement layer 19 to restrain the pressure when filling the epoxy resin during pouring, and acts as an external mold.

[0038] The insulating support tube 6 in the embodiment of the present invention is an epoxy resin tube or a polytetrafluoroethylene tube, etc., and its thickness is 1-5 mm. The thickness of the heat shrinkable insulating tube layer is 1-3 mm. The thickness of the epoxy resin filling 3 is designed according to the insulation grade of the product.

[0039] The crepe paper functional layer in the embodiment of the present invention is formed by wrapping crepe paper with shielding and insulating functions, and its thickness is 0.1-0.5 mm. The wrapping method is dense winding; specifically, semi-conductive crepe paper, insulating crepe paper and copper tape are wrapped around the equalizing tube 4 and the insulating support tube 6 in sequence to form the crepe paper functional layer and the copper tape functional layer respectively.

[0040] Among them, see Figure 4-7 The voltage-equalizing tube 4 in the embodiment of the present invention is a non-magnetic metal tube, and annular bosses are coaxially provided at the circular holes at both ends thereof. The voltage-equalizing tube 4 is specifically an aluminum tube or an aluminum alloy tube. The annular boss is gap-matched with the inner wall of the insulating support tube 6 or is slightly smaller than the inner diameter of the insulating support tube 6. The annular boss is inserted into the insulating support tube 6 (fixed by gluing or sealing ring (an annular groove for accommodating the sealing ring can be provided on one of the structures)) to realize the connection between the voltage-equalizing tube 4 and the insulating support tube 6, and its length is 10-30mm to ensure the stability of the connection. The outer diameter of the voltage-equalizing tube 4 is consistent with the outer diameter of the insulating support tube 6 (for easy wrapping), and its inner diameter is 0.5-2.0mm smaller than the inner diameter of the insulating support tube 6 (for easy installation of equipotential wires).

[0041] Further, see Figure 4-9 The flange 5 in the embodiment of the present invention is a non-magnetic metal flange (aluminum flange or steel flange, preferably) or a high-strength (mechanical strength) non-metallic flange, etc. It is a ring-shaped columnar structure (the outer diameter is basically the same as the inner diameter of the insulating jacket 2) that matches the size of the insulating jacket 2. Its inner hole is flush with the inner wall of the insulating support tube 6 and a step hole for inserting the insulating support tube 6 is coaxially provided on it (at the circular hole). A plurality of outer ring grooves 9 are coaxially provided on its outer peripheral surface to ensure the stability of gluing and the sealing of the connection. The step hole is clearance-matched with the insulating support tube 6 or its inner diameter is slightly larger than the outer diameter of the insulating support tube 6; the insulating support tube 6 is inserted into the step hole to realize the connection between the insulating support tube 6 and the flange 5, and they are fixed by gluing or sealing ring (a ring groove for accommodating the sealing ring can be provided on one of the structures). Further, if the flange 5 and the insulating support tube 6 are sealed by gluing, a plurality of inner ring grooves 18 can be provided on the inner wall of the step hole to ensure the stability of gluing and the sealing of the connection. The plurality of outer annular grooves 9 are all coaxially arranged with the flange 5 and arranged side by side in the axial direction of the flange 5 , and the plurality of inner annular grooves 18 are all coaxially arranged with the flange 5 and arranged side by side in the axial direction of the flange 5 .

[0042] Preferably, see Figure 4-9 In the embodiment of the present invention, two pouring function holes 7 are symmetrically arranged on the flange 5 (the two pouring function holes 7 are poured at the same time to ensure uniformity), and the flanges 5 at both ends of the inner support frame 1 are symmetrically arranged, and the positions of the pouring function holes 7 of the two flanges 5 are the same to ensure uniformity of pouring.

[0043] Among them, see Figure 4-9The flange holes in the embodiment of the present invention are all threaded holes that penetrate the flange 5 and are arranged axially along the inner support frame 1. Multiple flange holes are evenly distributed. For example, there are six flange holes evenly distributed on the flange 5, two of which are pouring function holes 7, and the remaining four are ordinary flange holes 8. The inner ends of the other flange holes (ordinary flange holes 8) except the pouring function hole 7 are provided with plugs 10 (specifically, they can be made of plastic) to close them, and the pouring function hole 7 can be threadedly connected with the pouring head 11.

[0044] Example 2

[0045] See also Figure 4-9 Embodiment 2 provides a method for preparing an insulating shielding tube without an inner mold, comprising the following steps:

[0046] (1) Two insulating support tubes 6 are sleeved on the annular bosses at both ends of the equalizing tube 4, and flanges 5 are sleeved on the other ends of the two insulating support tubes 6. The equalizing tube 4, the insulating support tube 6 and the flange 5 are coaxially fixed together, and the equalizing tube 4, the insulating support tube 6 and the flange 5 are sealed by adhesive or sealing rings to form an internal support skeleton 1. The inner ends of some flange holes are closed to form ordinary flange holes 8, and the unclosed flange holes are connected to the insulating filling cavity as casting function holes 7.

[0047] (2) A tensioning mold 12 is arranged on the inner support frame 1 to tighten and fix the pressure equalizing tube 4, the insulating support tube 6 and the flange 5 together along the axial direction.

[0048] (3) Corrugated paper and copper tape with shielding and insulating functions are wrapped around the voltage-equalizing tube 4 and the insulating support tube 6 from the inside to the outside to form a corrugated paper functional layer and a copper tape functional layer respectively.

[0049] (4) A heat shrinkable insulating tube (matched with the outer wall of the flange 5) is arranged outside the inner support frame 1 to form an insulating jacket 2. Both ends of the heat shrinkable insulating tube are sleeved on the outer wall of the flange 5 on the corresponding side and fixed by gluing.

[0050] (5) A clamping structure 13 is provided outside the insulating jacket 2 and located at the flange 5 to fasten the insulating jacket 2 (end portion) to the flange 5; wherein the clamping structure 13 is specifically a clamping hoop, and its function is to ensure the sealing between the flange 5 and the insulating jacket 2.

[0051] (6) A cloth tape is wrapped around the outside of the insulating jacket 2 to form a casting reinforcement layer 19 to restrict the pressure of subsequent casting and prevent the heat shrinkable insulating tube layer from being deformed due to pressure.

[0052] (7) Under vacuum conditions, epoxy resin material is poured into the pouring function hole 7 of the flange 5 on one side at a pouring temperature of 110-150°C and a pouring pressure of 0.1-0.3MPa; the pouring function hole 7 of the flange 5 on the other side discharges the material until there are no bubbles in the material (the purpose of removing bubbles is to meet the insulation electrical performance indicators and to avoid ionization discharge of bubbles inside under high voltage, thereby affecting the insulation performance of the shielding tube).

[0053] (8) After cooling and molding, the tensioning mold 12, the clamping structure 13, the pouring reinforcement layer 19 and the pouring head 11 are removed to obtain the product.

[0054] Among them, see Figure 4-6 The tensioning die 12 in the embodiment of the present invention is used to press the flange, which plays a further role in sealing and ensuring, and is also convenient for axial rotation during the wrapping operation. Specifically, the tensioning die 12 includes a screw 14 and two top plates 15 at both ends thereof (specifically angle steels arranged outward), and the screw 14 is arranged along the axis of the inner support frame 1. The top plate 15 is arranged perpendicular to the screw 14 (arranged along the radial direction of the inner support frame 1), and its two ends are pressed against the outer end surface of the flange 5 and are respectively fixedly connected to two symmetrically arranged flange holes (ordinary flange holes 8) (fixed by bolts or fixed by pins, etc.) to center the screw 14, and a buffer pad 16 (specifically a rubber pad) is provided on the inner side to prevent damage or deformation of the flange. One of the top plates 15 is fixed to the screw rod 14 by two nuts 17 on its inner and outer sides, and the other top plate 15 can be adjusted along the position of the screw rod 14 on the screw rod 14 by a nut 17 on its outer side (the nut is usually disassembled to achieve the combination of the tensioning mold 12 and the shielding tube), and a through hole (specifically a round hole smaller than the nut 17) is provided in the middle of the top plate 15 for the screw rod 14 to pass through.

[0055] In step (5) of the embodiment of the present invention, the thickness of the poured reinforcement layer 19 is 1-3 mm and it is wrapped with a woven cloth tape with a thickness of 0.1-0.3 mm.

[0056] Among them, see Figure 6 In step (7) of the embodiment of the present invention, the pouring head 11 is threadedly connected to the pouring function hole 7 to realize the feeding and discharging of the epoxy resin.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An insulating shielding cylinder without inner mold preparation, characterized in that: The invention comprises an inner support frame (1), an insulating jacket (2) coaxially arranged outside the inner support frame (1), and epoxy resin filling (3) therebetween; the inner support frame (1) comprises a voltage-equalizing tube (4) in the middle, two flanges (5) at both ends, and two insulating support tubes (6) between the voltage-equalizing tube (4) and the flanges (5); the voltage-equalizing tube (4), the insulating support tube (6) and the flanges (5) are coaxially arranged and sealed with each other by adhesive sealing or sealing ring; the voltage-equalizing tube (4) and the insulating support tube (6) are wrapped with a corrugated outer layer. The two ends of the insulating jacket (2) are sleeved and fastened on the flanges (5) on the corresponding sides to form a ring-shaped insulating filling cavity with the inner support frame (1) and the flange (5); the flange (5) is provided with a plurality of flange holes and only some of the flange holes are connected to the insulating filling cavity to form a pouring functional hole (7); the epoxy resin material enters the insulating filling cavity through the pouring functional hole (7) to form the epoxy resin filling (3) and impregnates the crepe paper functional layer to form a frame; the insulating jacket (2) includes a heat shrinkable insulating tube layer.

2. The insulating shielding cylinder without inner mold preparation according to claim 1 is characterized in that: The insulating support tube (6) is an epoxy resin tube or a polytetrafluoroethylene tube, and its thickness is 1-5 mm; the thickness of the heat shrinkable insulating tube layer is 1-3 mm.

3. The insulating shielding cylinder without inner mold preparation according to claim 1 is characterized in that: The crepe paper functional layer is formed by wrapping crepe paper with shielding and insulating functions, and has a thickness of 0.1-0.5 mm.

4. The insulating shielding cylinder without inner mold preparation according to claim 1 is characterized in that: The voltage-equalizing tube (4) is a non-magnetic metal tube, and annular bosses are coaxially arranged at both ends of the tube; the annular boss is inserted into the insulating support tube (6) to realize the connection between the voltage-equalizing tube (4) and the insulating support tube (6), and its length is 10-30 mm; the outer diameter of the voltage-equalizing tube (4) is consistent with the outer diameter of the insulating support tube (6), and its inner diameter is 0.5-2.0 mm smaller than the inner diameter of the insulating support tube (6).

5. The insulating shielding cylinder without inner mold preparation according to claim 1 is characterized in that: The flange (5) is a non-magnetic metal flange or a high-strength non-metallic flange, and is a cylindrical structure that matches the size of the insulating sleeve (2). Its inner hole is flush with the inner wall of the insulating support tube (6) and a step hole for inserting the insulating support tube (6) is coaxially provided on it, and a plurality of outer annular grooves (9) are coaxially provided on its outer peripheral surface; the insulating support tube (6) is inserted into the step hole to achieve the connection between the insulating support tube (6) and the flange (5).

6. The insulating shielding cylinder without inner mold preparation according to claim 1, characterized in that: Two pouring function holes (7) are symmetrically arranged on the flange (5), and the flanges (5) at both ends of the inner support frame (1) are symmetrically arranged.

7. The insulating shielding cylinder without inner mold preparation according to claim 1 is characterized in that: The flange holes are all threaded holes that penetrate the flange (5) and are arranged axially along the inner support frame (1). The inner ends of the other flange holes except the pouring function hole (7) are provided with plugs (10) to close them. The pouring function hole (7) can be threadedly connected with the pouring head (11).

8. A method for preparing an insulating shielding tube without inner mold preparation, characterized in that: The following steps are involved: (1) Two insulating support tubes (6) are sleeved on the annular bosses at both ends of the equalizing tube (4), and flanges (5) are sleeved on the other ends of the two insulating support tubes (6). The equalizing tube (4), the insulating support tube (6) and the flanges (5) are sealed by adhesive or sealing rings to form an internal support framework (1), the inner ends of some flange holes are closed, and the unclosed flange holes are used as casting function holes (7); (2) a tensioning mold (12) is arranged on the inner support frame (1) to tighten and fix the pressure equalizing tube (4), the insulating support tube (6) and the flange (5) together in the axial direction; (3) Wrapping crepe paper and copper tape having shielding and insulating functions around the voltage-equalizing tube (4) and the insulating support tube (6) from the inside to the outside in order to form a crepe paper functional layer and a copper tape functional layer, respectively; (4) a heat-shrinkable insulating tube is arranged outside the inner support frame (1) to form an insulating jacket (2), and both ends of the heat-shrinkable insulating tube are sleeved on the outer wall of the flange (5) on the corresponding side and fixed by gluing; (5) a clamping structure (13) is provided outside the insulating jacket (2) and at the flange (5) to fasten the insulating jacket (2) to the flange (5); (6) wrapping a cloth tape around the insulating jacket (2) to form a cast reinforcement layer (19); (7) pouring epoxy resin material into the pouring function hole (7) of the flange (5) on one side under vacuum conditions, with a pouring temperature of 110-150° C. and a pouring pressure of 0.1-0.3 MPa; discharging material from the pouring function hole (7) of the flange (5) on the other side, and stopping pouring when there are no bubbles in the discharged material; (8) After cooling and forming, the tensioning mold (12), the clamping structure (13) and the pouring reinforcement layer (19) are removed to obtain the product.

9. The method according to claim 8, characterized in that In step (2), the tensioning mold (12) includes a screw (14) and two top plates (15) at both ends thereof, wherein the screw (14) is arranged along the axis of the inner support frame (1); the top plate (15) is arranged perpendicular to the screw (14), and its two ends are pressed against the end surface of the flange (5) and are respectively fixedly connected to two symmetrically arranged flange holes to center the screw (14), and a buffer pad (16) is provided on the inner side thereof; one of the top plates (15) is fixed to the screw (14) by two nuts (17) on its inner and outer sides, and the other top plate (15) can be adjusted along the position of the screw (14) by a nut (17) on its outer side, and a through hole for the screw (14) to pass through is provided in the middle of the top plate (15).

10. The method according to claim 8, characterized in that In step (5), the pouring reinforcement layer (19) has a thickness of 1-3 mm and is formed by wrapping a woven fabric tape with a thickness of 0.1-0.3 mm.

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