A gas duct rod assembly for transformer casting

Abstract

This utility model relates to a gas channel rod assembly for transformer casting, comprising a gas channel rod group, wherein the gas channel rod group includes multiple round rods arranged in a line and wrapped with a thin film. The round rods have reinforcing metal wires inside, and the outer surface of the thin film is coated with oil. This utility model allows for the use of round rods of appropriate diameter and quantity according to actual needs, forming gas channel rod assemblies of different lengths by wrapping them with the thin film. Furthermore, the gas channel rod assembly of this utility model can be freely bent according to the curvature of the gas channel orifice, making it more flexible in use. Multiple reinforcing metal wires are provided inside each round rod to improve strength, thus extending the service life of the round rods. This utility model utilizes the thin film to wrap each round rod, thereby forming a complete and smooth curved surface on the inner wall of the gas channel orifice after casting, thus avoiding the problem of resin tip formation.

Description

Technical Field

[0001] This utility model relates to the field of transformers, specifically to a gas channel rod assembly for transformer casting. Background Technology

[0002] In the winding process of traditional dry-type transformer coils, air passage rods or plates are used in conjunction with casting molds to form the coil air passages. For example, in patent CN216054269U, an outer mold, inner mold, upper end plate, and lower end plate are used in conjunction with a fixed air passage rod for casting. After casting, the air passage rod is removed to form the air passage structure of the coil. However, the air passage structure formed by this patent includes multiple air passage holes arranged along the circumference of the coil, and the cross-section of the air passage holes is approximately rectangular. Similarly, the air passage structure in patent CN210628075U also includes multiple air passage holes arranged along the circumference of the coil, and its cross-section is also approximately rectangular.

[0003] With technological advancements, the dry-type transformer industry has seen the emergence of arc-shaped elongated air duct structures, which increase the heat dissipation space of the air duct. Existing technologies typically use combined, spliced ​​air duct rods or plates to create these elongated air ducts. For example, patent CN104157444A discloses a transformer air duct structure that utilizes a group of air duct rods with a similar square cross-section arranged side-by-side to form arc-shaped elongated air ducts. However, this combined, spliced ​​air duct rod assembly has the following drawbacks:

[0004] First, its materials are only polyoxymethylene and modified resin, and it can only be used about 20 times in the curing environment of the casting coil, and it is prone to aging and cracking.

[0005] Second, these air duct rods or air duct plates are usually approximately square or rectangular in cross-section. Due to the rounded corners of the air duct rods at the joints, there is a problem that the resin tips cannot be eliminated after the coil is cast and cured. In dry-type transformer products with voltage levels of 10kV and above, the tips of the insulation material will cause uneven electric field distribution, and charges are more likely to accumulate at the tips, forming a stronger electric field than other parts. When the local electric field strength exceeds the withstand strength of the insulation material, it will trigger partial discharge. This partial discharge will generate heat and active substances, and gradually erode the insulation material, causing the insulation performance to decline, and then problems such as short circuits and leakage will occur.

[0006] Another existing technology involves directly using an arc-shaped air duct plate for casting. For example, patent CN205984548U discloses a tile-type air duct, which includes an upper limit position of the air duct plate, a lower limit position of the air duct plate, a mold base, an air duct plate, an inner mold, an outer mold, and other structures. The air duct plate in this patent includes both arc-shaped and straight air duct plates. However, the arc-shaped air duct plate is a fixed structure, and its length and curvature cannot be flexibly adjusted according to actual conditions. In addition, the arc-shaped air duct plate is made of iron material, and its processing requires maintaining high pressing precision to meet the curvature requirements of the long holes in the air duct. Utility Model Content

[0007] The purpose of this invention is to provide a gas channel bar assembly for transformer casting, which can form gas channel bar groups of different lengths and curvatures as needed, while improving the service life of the round bars and avoiding the problem of resin tip formation on the inner wall of the long holes of the gas channel.

[0008] The objective of this utility model is achieved through the following technical solution:

[0009] A transformer casting air channel bar assembly includes an air channel bar group, wherein the air channel bar group includes a plurality of round bars arranged in a line and wrapped by a film, the round bars having reinforcing metal wires inside, and the film being coated with oil on the outside.

[0010] The upper end of the airway rod assembly is fixed by an upper end plate, and the lower end is fixed by a lower end plate.

[0011] The upper end plate is provided with an arc-shaped hole for inserting the upper end of the air supply rod assembly; the lower end plate is provided with an arc-shaped hole for inserting the lower end of the air supply rod assembly.

[0012] The airway rod assembly is equipped with end clamps at both the upper and lower ends.

[0013] The end clamp includes a hollow joint, a sphere, a metal rope, a locking bolt, and a locking nut. The hollow joint and the sphere are staggered and connected in series by the metal rope. The front end of the locking bolt is inserted into the adjacent hollow joint and fixed to the metal rope. The locking nut is sleeved on the locking bolt. The locking bolts of the two end clamps located on the same side are connected by a connecting assembly.

[0014] The connecting assembly includes a connecting bolt and a connecting nut, wherein the connecting bolt passes sequentially through a locking bolt located on the same side of the two end clamps and is then threadedly connected to the connecting nut.

[0015] After the film wraps around each round bar, a binding guide wire is wrapped around the outer side of the middle part of the film.

[0016] The advantages and positive effects of this utility model are as follows:

[0017] 1. This utility model can use round bars of appropriate diameter and quantity according to actual needs, and form airway bar assemblies of different lengths by wrapping them with a film. At the same time, the airway bar assemblies of this utility model can be freely bent according to the curvature of the airway orifice, making them more flexible to use.

[0018] 2. Each round bar in this invention has multiple reinforcing metal wires inside to improve its strength, which can increase the service life of the round bar.

[0019] 3. This utility model utilizes a thin film to wrap each round rod, thereby forming a complete and smooth curved surface on the inner wall of the long hole of the air channel after casting, thus avoiding the problem of resin tip formation.

[0020] 4. This utility model can use flexible end clamps to help fix both ends of the airway rod assembly and use binding guide wires to fix the middle part of the airway rod assembly. This can ensure that the membrane is firmly fixed during installation, while also allowing the airway rod assembly to be flexibly bent to form the required arc. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the usage state of this utility model.

[0022] Figure 2 for Figure 1 Schematic diagram of the end structure of the middle airway rod assembly.

[0023] Figure 3 for Figure 2 Front view of the end of the middle airway rod assembly.

[0024] Figure 4 This is a schematic diagram of an airway rod structure in the prior art.

[0025] Figure 5 This is a schematic diagram illustrating the state in which an end clamp is used for auxiliary fixing in one embodiment of the present invention.

[0026] Figure 6 for Figure 5 Enlarged schematic diagram of the mid-end clamp.

[0027] Among them, 1 is a round bar, 101 is a reinforcing metal wire, 2 is a thin film, 3 is an airway elongated hole, 4 is an airway rod, 401 is a rounded corner, 5 is an end clamp, 501 is a hollow section, 502 is a sphere, 503 is a locking nut, 504 is a locking bolt, 505 is a connecting bolt, and 506 is a connecting nut. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings.

[0029] like Figures 1-3As shown, the present invention includes an airway rod assembly, and the airway rod assembly includes a plurality of round rods 1 arranged in a line and wrapped by a film 2. The round rods 1 are provided with reinforcing metal wires 101 inside, and the film 2 is coated with oil on the outside.

[0030] In this embodiment, the round rod 1 can be made of insulating materials such as polyoxymethylene, polytetrafluoroethylene, and polyesterimide, the reinforcing metal wire 101 is a steel wire, the film 2 is a polyester film, and the outer side of the film 2 is coated with silicone oil.

[0031] In this embodiment, during casting, the upper end of the airway rod assembly is fixed by an upper end plate, and the lower end is fixed by a lower end plate. The upper end plate has an arc-shaped hole for inserting and fixing the upper end of the airway rod assembly, and the lower end plate has an arc-shaped hole for inserting and fixing the lower end of the airway rod assembly. During fixing, the film 2 wrapping each round rod 1 is held in place by the arc-shaped holes in the upper and lower end plates, thus achieving the purpose of tightly wrapping each round rod 1 with the film 2. Both the upper and lower end plates are technologies known in the art. For example, the upper and lower end plate structure in patent CN216054269U (this utility model uses arc-shaped holes instead of conventional airway rod holes) can be used, or the upper and lower limit plate structure of the airway in patent CN205984548U can be used.

[0032] Other examples Figures 5-6 As shown, this utility model can also provide end clamps 5 at the ends of the airway rod assembly to achieve auxiliary fixation according to actual needs. For example, if the airway rod assembly contains a large number of round rods 1 and has a long arc length, after the airway rod assembly is placed between the inner mold and the outer mold of the casting mold during installation, its two ends are first clamped and fixed by the end clamps 5, and then inserted into the arc holes on the corresponding end plates. This can prevent the film 2 of the airway rod assembly from spreading out during installation.

[0033] like Figures 5-6 As shown, in this embodiment, the end clamp 5 includes a hollow section 501, a sphere 502, a metal rope, and a locking assembly. The hollow section 501 and the sphere 502 are staggered and connected in series by the metal rope. Both the hollow section 501 and the sphere 502 have through holes for the metal rope to pass through. The two ends of the metal rope are respectively fixed to the locking assemblies on corresponding sides. The locking assemblies of the two end clamps 5 located on the same side are connected by a connecting assembly, thereby achieving the purpose of clamping the end of the airway rod assembly. Both the hollow section 501 and the sphere 502 are made of metal.

[0034] like Figures 5-6As shown, in this embodiment, the locking assembly of the end clamp 5 includes a locking bolt 504 and a locking nut 503, wherein the locking nut 503 is sleeved on the locking bolt 504, and the front end of the locking bolt 504 is inserted into the adjacent hollow section 501 and fixedly connected to the metal rope. In use, the locking bolts 504 in the locking assemblies on both sides are respectively inserted into the corresponding adjacent hollow sections 501. Then, the operator screws the locking nuts 503 on both sides and moves them along the locking bolts 504 to clamp each hollow section 501 and each ball 502, thereby locking the overall length and position of each hollow section 501 and each ball 502.

[0035] like Figures 5-6 As shown, in this embodiment, the metal rope can be a steel wire rope, and its end can be fixed to the front end of the locking bolt 504 by welding.

[0036] like Figures 5-6 As shown, in this embodiment, the connecting assembly includes a connecting bolt 505 and a connecting nut 506. The connecting bolt 505 passes through the locking bolt 504 located on the same side of the two end clamps 5 in sequence and is threadedly connected to the connecting nut 506. In this embodiment, the position of the connecting nut 506 on the connecting bolt 505 can be adjusted by screwing the connecting nut 506, and the clamping force of the two end clamps 5 on the end of the airway rod assembly can also be flexibly fine-tuned.

[0037] In addition, during the installation of the airway rod assembly, a binding guide wire can be first wrapped around the outer side of the middle of the membrane 2 to ensure that the middle of the membrane tightly wraps around each round rod 1, for example when the axial length of the airway rod assembly is relatively long, and then the airway rod assembly is inserted between the inner mold and the outer mold. In this embodiment, the binding guide wire can be a copper guide wire.

[0038] The working principle of this utility model is as follows:

[0039] The following steps are included when using this utility model:

[0040] Step 1: Lay a film 2 of appropriate width and coated with oil on both sides according to the arc length of the airway orifice 3. In this embodiment, the width of the film 2 is 2.5 times the arc length of the airway orifice 3, and the length of the film 2 is greater than the height of the coil, so as to ensure that the upper and lower ends of the film 2 can be fixed by the upper and lower end plates.

[0041] In this embodiment, the film 2 is made of polyester film because it has good flexibility and insulation properties. At the same time, the two sides of the film 2 are coated with silicone oil to facilitate subsequent operations and final removal.

[0042] Step 2: Select a suitable diameter and number of round rods 1, and arrange each round rod 1 in a row on one side of the film 2. During the arrangement process, ensure that the adjacent round rods 1 are in close contact, so that the whole group of round rods 1 are arranged tightly and neatly on the film 2 until the designed length of the coil air passage 3 is reached.

[0043] Step 3: Fold the unused side of the film 2 over each of the round rods 1. When folding, ensure that the film 2 completely and tightly wraps around each of the parallel round rods 1, so that each round rod 1 is completely sealed inside the film 2, thus forming a complete air channel rod assembly. Additionally, during the wrapping process, smooth the film 2 to avoid wrinkles or air bubbles, which could affect subsequent coil winding and casting / curing processes.

[0044] In this step, after the membrane 2 wraps around each round rod 1, a guide wire can be wrapped around the outer side of the middle part of the membrane 2 as needed (for example, when the axial length of the airway rod group is relatively long) to ensure that the middle part of the membrane tightly wraps around each round rod 1, thereby ensuring that the membrane 2 will not come apart locally during subsequent installation.

[0045] Step 4: Place the air channel rod assembly in the casting mold (between the inner mold and the outer mold) and position it at the air channel long hole 3 of the coil. Use the upper end plate to fix the upper end of the air channel rod assembly and use the lower end plate to fix the lower end of the air channel rod assembly.

[0046] In this step, such as Figures 5-6 As shown, depending on the needs (e.g., when the airway rod assembly contains a large number of round rods 1 and the arc length is long), end clamps 5 can be set at both ends of the airway rod assembly to help fix the film 2, ensuring that the film 2 can tightly wrap each round rod 1 during subsequent installation and will not come apart. Then, the upper end plate and the lower end plate are used to fix the airway rod assembly.

[0047] Once all the air duct rods have been placed, this invention can proceed with the winding of the transformer coil and subsequent casting.

[0048] like Figure 1 As shown, after the coil completes the resin casting and curing process, the air channel rod assembly (including the film 2 and each round rod 1) needs to be removed from the cast coil. At this time, since the polyester film used in this embodiment is coated with silicone oil on both sides, the adhesion between it and the cured resin is small, making it easy to extract and remove the air channel rod assembly. After removal, an elongated air channel hole 3 that meets the design requirements is formed inside the coil.

[0049] Compared to existing technologies, this invention firstly allows for the use of round rods 1 of appropriate diameter and quantity according to actual needs, which are then wrapped with a thin film 2 to form airway rod assemblies of different lengths. Furthermore, the airway rod assemblies of this invention can be freely bent according to the curvature of the airway elongated holes 3, thus offering greater flexibility in use. Secondly, each round rod 1 in this invention has multiple reinforcing metal wires 101 inside to improve strength, thereby increasing the service life of the round rod 1. Compared to the existing technology where the airway rod 4 can be used approximately 20 times in the curing environment of the casting coil, the round rod 1 of this invention can be used approximately 40 times. Furthermore... Figure 4 As shown, the airway rod 4 in the prior art is usually an approximately square or rectangular structure with rounded corners 401. However, for assembled airway rod groups, the presence of two adjacent rounded corners 401 on the splicing side of two adjacent airway rods 4 results in resin sharp points between adjacent rounded corners 401 after casting, which cannot be eliminated. This leads to uneven electric field distribution, causing problems such as partial discharge. Figures 1-3 As shown, this utility model utilizes a thin film 2 to wrap each round rod 1, thereby forming a complete and smooth curved surface on the inner wall of the elongated air passage 3 after casting, thus avoiding the aforementioned problem of resin tip.

[0050] In this embodiment, the manufacturing process of the round rod 1 is as follows:

[0051] Step 1: Melting and plasticizing the polyoxymethylene resin granules. Specifically, the mixed raw materials are added to the hopper of an extruder, and the raw materials are conveyed forward by the rotating screw. The temperature in the heating section of the extruder is controlled at 160-200℃, and the raw materials are gradually heated and melted to form a uniform melt. The extruder is a commercially available product.

[0052] Step Two: The end of the steel wire coil (i.e., reinforcing metal wire 101) of the corresponding specification is placed inside the extrusion die. After the wire end passes through the extrusion die, it is clamped by a moving jaw to achieve uniform traction and movement. Then, the molten polyoxymethylene is pushed into the extrusion die (the die cavity is circular, which determines the diameter of the rod), and a cylindrical billet is continuously extruded through the die opening of the extrusion die. At the same time, the wire end is driven by the moving jaw to move in coordination with the billet extrusion process, so that the steel wire is placed in the cylindrical billet along with the billet. The moving jaw, extrusion die, etc. are all commercially available products.

[0053] Step 3: The extruded hot cylindrical billet enters a cooling sleeve and is rapidly cooled by cold air inside the sleeve, causing the billet to solidify and form a rod. The cooling sleeve is a commercially available product.

[0054] Step 4: After cooling, the bar stock is pulled at a constant speed by a traction machine, and the traction speed is matched with the extrusion speed of the extrusion die to ensure that the bar stock is not stretched or piled up. Finally, the bar stock is cut into individual bars by a cutting device according to a set length (e.g., 1 meter, 2 meters, etc.). Both the traction machine and the cutting device are commercially available products.

[0055] The manufacturing process of the above-mentioned round bar 1 is a well-known technology in this field.

Claims

1. A gas ducting rod assembly for transformer casting, characterized by: The application relates to a gas channel rod group, which comprises a plurality of round rods (1) arranged in a line and wrapped by a film (2), the round rods (1) are internally provided with reinforcing metal wires (101), and the outer side of the film (2) is coated with oil.

2. The transformer pouring vent rod assembly of claim 1, wherein: The upper end of the gas channel rod group is fixed by an upper end plate, and the lower end is fixed by a lower end plate.

3. The transformer pouring vented bushing assembly of claim 2, wherein: An upper end plate arc-shaped hole for inserting the upper end of the gas channel rod group is arranged on the upper end plate; and a lower end plate arc-shaped hole for inserting the lower end of the gas channel rod group is arranged on the lower end plate.

4. The transformer pouring vented bushing assembly of claim 2, wherein: The upper end and the lower end of the gas channel rod group are both provided with end clamps (5).

5. The transformer pouring venting rod assembly of claim 4, wherein: The end clamps (5) comprise hollow sections (501), spherical balls (502), metal ropes, locking bolts (504) and locking nuts (503), wherein the hollow sections (501) and the spherical balls (502) are alternately arranged and connected by the metal ropes, the locking bolts (504) are inserted into the adjacent hollow sections (501) and are fixedly connected with the metal ropes, the locking nuts (503) are sleeved on the locking bolts (504), and the locking bolts (504) on the same side of the two end clamps (5) are connected by a connecting assembly.

6. The transformer pouring vented rod assembly of claim 5, wherein: The connecting assembly comprises connecting bolts (505) and connecting nuts (506), wherein the connecting bolts (505) are sequentially threaded through the locking bolts (504) on the same side of the two end clamps (5) and are threadedly connected with the connecting nuts (506).

7. The transformer pouring vented bushing assembly of claim 1, wherein: After the film (2) wraps the round rods (1), a binding guide wire is wound on the outer side of the middle part of the film (2).

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