Manufacturing mold and process for ultra-high-voltage ultra-long narrow-edge angle ring

Abstract

The invention provides a mold and process for manufacturing an ultra-high-pressure ultra-long narrow-corner ring, the mold comprises an inner mold, an outer mold and a locking piece, and a G-shaped clamp is adopted as a fastening piece; processing the wet paper into an arc paper tape according to a mold arc; the mold is cleaned; the wet paper is laid along the arc of the mold and flatted by hand, and the wet paper cannot be wrinkled; the two pieces of angle steel are subjected to mold closing, the outer portions are clamped through a plurality of G-shaped clamps, and mold neutral areas between the adjacent G-shaped clamps are wound and fastened through elastic bandages; the whole body is put into a drying oven to be dried, the drying temperature is 110-115 DEG C, and the drying time is 6-8 hours; and demolding after baking, cutting edge margins, and processing to the size of a finished product according to specifications. According to the manufacturing method, the specific mold is used, the single angle ring can be manufactured under the condition that a pressing machine is not used, the arc length of the angle ring is not limited, and manufacturing of the angle ring with the long arc length is achieved.

Description

Technical Field

[0001] This invention relates to the field of ultra-high voltage transformer technology, and in particular to a manufacturing mold and process for an ultra-high voltage ultra-long narrow-angle ring. Background Technology

[0002] With the increasing voltage and capacity of ultra-high voltage and extra-high voltage oil-immersed power transformers, the diameter of the transformer coils is also increasing. Considering ease of use and to reduce manufacturing difficulties, coil end insulation structures typically use coil corner rings with an arc length of approximately 600mm installed at the coil ends. These corner rings are formed by overlapping multiple pieces end-to-end. However, due to the increased transformer diameter, using conventional end ring overlapping methods results in excessive overlap at the coil ends, increasing the difficulty of transformer assembly and degrading end insulation performance, thus increasing the risk of failure. Therefore, for corner rings used in ultra-high voltage and extra-high voltage oil-immersed power transformers, a longer arc length for a single corner ring is better. This not only reduces the risk of transformer testing failures but also simplifies the product assembly process, further improving its reliability.

[0003] Generally, insulation component manufacturers can only process corner rings with an arc length of around 600mm, mainly due to limitations in the corner ring hot-pressing process. Currently, domestic corner ring presses have a fixed upper mold structure, with the lower mold using a hydraulic cylinder to drive a movable work platform to achieve mold closing. The entire manufacturing process involves using a corner ring mold to hot-press a wet paper blank into a corner ring product of a certain thickness. Corner ring production is limited by the process, mold, and press, so the arc length of narrow-edge corner rings generally cannot be too long (typically 400-700mm). An excessively long arc length will prevent the wet paper from being laid flat during hot pressing, resulting in uneven product thickness. In severe cases, it can even cause wrinkles on the edges of the hot-pressed corner ring, leading to products that do not meet usage requirements. While the traditional wet molding process can produce corner rings with arbitrary arc lengths, the manufacturing cost is too high, with a single mold costing 5,000 to 6,000 yuan, and the manufacturing efficiency is low, making it uneconomical for corner ring products.

[0004] In view of this, it is necessary to improve the existing corner ring manufacturing molds and processes to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in order to overcome the shortcomings of the prior art, the present invention provides a manufacturing mold and process for ultra-high voltage ultra-long narrow-edge corner rings. By using a specific mold, a single corner ring can be manufactured without the use of a press, and the arc length of the corner ring is not limited, thus realizing the manufacturing of long arc long corner rings.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a manufacturing mold for ultra-high voltage ultra-long narrow corner ring, including an inner mold, an outer mold and a locking component. The cross-section of the inner mold and the outer mold is L-shaped. The outer mold is a concave mold and the inner mold is a convex mold. The inner mold is embedded in the inner corner of the outer mold and can form a mold cavity with uniform thickness between the two opposing surfaces. The mold cavity is used to place wet paper to form the corner ring. The locking component is used to lock the inner mold and the outer mold, so that the two are clamped together and pressure is applied to the wet paper in the mold cavity.

[0007] If the inner corner of the narrow corner ring is a sharp corner, stress concentration will occur in the wet paper during manufacturing, which can easily damage the wet paper and cause cracking in the product. Therefore, the outer edge of the inner mold is rounded, so that the inner corner of the molded product is rounded, avoiding stress concentration. Preferably, the radius R of the rounded corner is ≤1mm.

[0008] Preferably, both the inner and outer molds are made of angle steel. Preferably, the angle steel is made of 304 stainless steel.

[0009] Preferably, the locking element is a G-type clamp.

[0010] Furthermore, in order to fully fix the mold and ensure that the wet paper is subjected to uniform force, an elastic strap is also included, which is wrapped around the outside of the inner mold and the outer mold to secure them.

[0011] Furthermore, the height of the cavity between the inner mold and the outer mold is H1, and the width of the cavity is H2, then H1≤50mm, H2≤50mm. Preferably, H1=H2, and is generally 50mm.

[0012] A manufacturing process for an ultra-high voltage ultra-long narrow corner ring, which uses the aforementioned manufacturing mold to manufacture the ultra-long narrow corner ring, further includes the following steps: S1: Wet paper preparation, processing the wet paper into an arc paper strip according to the arc of the mold; the wet paper production process adopts the conventional wet paper process; S2: Mold preparation and cleaning; the mold is made of angle steel, such as 304 stainless steel. The cleaning process usually involves removing foreign objects attached to the surface of the mold, such as paper scraps, black oxide layer, etc.

[0013] S3: Lay the wet paper along the arc of the outer mold, and pat it flat by hand. The wet paper should not have any wrinkles. S4: Close the inner mold and the outer mold together, and use several G-clamps to clamp the outside. Use elastic straps to wrap and secure the mold gap area between adjacent G-clamps. S5: Place the whole thing in an oven to dry at a temperature of 110-115℃ for 6-8 hours. S6: After baking, demold, trim the edge excess, and process to the finished product size according to specifications.

[0014] Preferably, the arc length of the manufactured ultra-long narrow corner ring can be machined to a maximum of 40% of the total circumference of the narrow corner ring. The arc of a single narrow corner ring can be machined to 140°-150°. The height h1 of the narrow corner ring can be machined to 8-40mm. The width h2 of the narrow corner ring can be machined to 8-40mm, and H1>h1, H2>h2 are satisfied.

[0015] Further optimization is made, with H1-h1 ranging from 10 to 15 mm and H2-h2 ranging from 10 to 15 mm.

[0016] The beneficial effects of this invention are as follows: This invention provides a manufacturing process for an ultra-high voltage ultra-long narrow-sided corner ring, which uses two angle steels as corner ring forming molds, lays wet paper between the two angle steels, and then uses elastic straps and G-clamps to apply external force to the angle steels to achieve the stress on the corner ring, thereby ensuring the uniformity of the corner ring thickness. Finally, the ultra-long corner ring is manufactured by heating the angle steel wrapped with wet paper as a whole. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a schematic diagram of the structure of the mold of the present invention.

[0019] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure of CC.

[0020] Figure 3 yes Figure 2 A magnified structural diagram of point A in the middle.

[0021] Figure 4 This is a schematic diagram of corner ring manufacturing using molds.

[0022] In the diagram: 1. Inner mold, 2. Outer mold, 3. Corner ring, 4. Rounded corner, 5. G-clamp. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figures 1-4 As shown, the present invention discloses a manufacturing mold for an ultra-high voltage ultra-long narrow-edge corner ring, comprising an inner mold 1, an outer mold 2, and a locking component. Both the inner mold 1 and the outer mold 2 have L-shaped cross-sections. The inner mold 1 is embedded within the inner corner of the outer mold 2, forming a uniformly thick mold cavity between their opposing surfaces. The mold cavity is used to hold wet paper to form the corner ring 3. The locking component is used to lock the inner mold 1 and the outer mold 2, clamping them together and applying pressure to the wet paper within the mold cavity. Preferably, the locking component is a G-type clamp 5. The outer edge of the inner mold 1 is rounded 4. Preferably, the radius R of the rounded corner 4 is ≤1mm. Preferably, both the inner mold 1 and the outer mold 2 are made of angle steel. To fully fix the mold and ensure uniform stress on the wet paper, an elastic strap is also included, which is wrapped around the outside of the inner mold 1 and the outer mold 2 to secure them. The height of the cavity between the inner and outer molds is H1, and the width of the cavity is H2. Therefore, H1 ≤ 50 mm and H2 ≤ 50 mm. Preferably, H1 = H2, and is generally 50 mm.

[0027] A manufacturing process for an ultra-high voltage ultra-long narrow corner ring 3, which uses the aforementioned manufacturing mold to manufacture the ultra-long narrow corner ring 3, further includes the following steps: S1: Prepare wet paper by processing the wet paper into an arc-shaped paper strip according to the arc of the mold.

[0028] S2: Mold preparation, cleaning the mold; in this embodiment, the mold is made of stainless steel and the surface is polished. No cleaning with any reagents is required before use. Just use soapy water to clean the oil stains on the surface of the mold, and then rinse it with clean water before use.

[0029] S3: Lay the wet paper along the arc of the outer mold, and flatten it by hand, ensuring there are no wrinkles. Whether it's a positive or negative angle ring, it's generally laid on one side of the concave mold, with the other half of the mold serving as the convex mold. In this embodiment, the outer mold is a concave mold, and the inner mold is a convex mold. Therefore, when laying the wet paper, it's first laid inside the inner corner of the outer mold. After laying, the inner mold is inserted into the inner corner of the outer mold to close the mold and press it onto the wet paper.

[0030] S4: After the inner mold and outer mold are closed, several G-type clamps 5 are used to clamp the outside. The gap area between adjacent G-type clamps 5 is secured with elastic straps. Preferably, the elastic straps and G-type clamps 5 are used together to apply external force. The G-type clamps 5 are evenly distributed at 100mm intervals. The G-type clamps 5 in the height and width directions can be set directly opposite each other or staggered. When arranging the G-type clamps 5, they are evenly fixed from the middle of the mold to both sides to avoid the mold from not being able to fit with the wet paper due to deformation and uneven pressure. Finally, the elastic straps are used for reinforcement to further improve the mold closing force.

[0031] S5: Place the whole unit in an oven to dry at a temperature of 110-115℃ for 6-8 hours.

[0032] S6: After baking, demold, trim the edge excess, and process to the finished product size according to specifications.

[0033] Preferably, the arc length of the manufactured ultra-long narrow corner ring 3 can be machined to 40% of the total circumference of the narrow corner ring, the arc corresponding to a single narrow corner ring can be machined to 140°-150°, the height h1 of the narrow corner ring can be machined to 8-40mm, and the width h2 of the narrow corner ring can be machined to 8-40mm, and satisfy H1>h1, H2>h2.

[0034] It should be noted that (1) during manufacturing, the wet paper at the edge of the mold cavity should not exceed the width of the mold cavity, that is, H1 > h1 and H2 > h2 are required. Preferably, the value range of H1-h1 is 10-15mm and the value range of H2-h2 is 10-15mm. In this embodiment, it is preferred that H1-h1 = H2-h2 = 10mm.

[0035] (2) The manufacturing of wet paper is a conventional process. The wet paper is cut into an arc shape using a water jet cutter. The arc of the wet paper and the arc of the mold must be basically aligned. When the width and height of the mold are 50mm, corner rings with a width and height of less than 40mm can generally be processed. Therefore, the wet paper can be fully laid on the surface of the mold. After the corner ring is formed, the edges need to be trimmed at the factory to obtain the final product size.

[0036] Application examples: Comparing the standard arc length of a 3-segment corner ring with an extra-long arc length of a 3-segment corner ring, taking a coil with a diameter of φ2100 as an example: A typical φ2100 diameter corner ring needs to be divided into 12 segments, with each segment overlapping 80mm, resulting in a single corner ring segment having an arc length of 630mm. If it could be manufactured with 8 segments, the arc length of a single corner ring segment would need to be processed to 905mm.

[0037] A conventional corner ring press can produce a corner ring 3 with an arc length of about 600mm, but it cannot increase the arc length to 900mm. However, by using the corner ring making mold and manufacturing method of the present invention, the arc length of the corner ring 3 is not limited. Only angle steel of the corresponding length is needed as the inner mold 1 and the outer mold 2, and with the help of G-type clamps 5, the production of corner rings 3 of a specific length can be achieved. This mold simplifies the corner ring 3 manufacturing equipment and manufacturing process, reduces costs, and realizes the production of long arc corner rings 3.

[0038] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the scope of the present invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A manufacturing mold for an ultra-high voltage, ultra-long, narrow-angle ring, characterized in that: It includes an inner mold, an outer mold, and a locking component. The cross-sections of the inner mold and the outer mold are both L-shaped. The inner mold is embedded in the inner corner of the outer mold and can form a mold cavity with uniform thickness between their opposing surfaces. The mold cavity is used to place wet paper to form a corner ring. The locking component is used to lock the inner mold and the outer mold, so that they are clamped together and pressure is applied to the wet paper in the mold cavity.

2. The manufacturing mold for the ultra-high voltage ultra-long narrow-angle ring as described in claim 1, characterized in that: The outer edges of the inner mold are rounded.

3. The manufacturing mold for the ultra-high voltage ultra-long narrow-angle ring as described in claim 1, characterized in that: Both the inner and outer molds are made of angle steel.

4. The manufacturing mold for the ultra-high voltage ultra-long narrow-angle ring as described in claim 1, characterized in that: The locking element is a G-type clamp.

5. The manufacturing mold for the ultra-high voltage ultra-long narrow-angle ring as described in claim 1, characterized in that: The height of the cavity between the inner mold and the outer mold is H1, and the width of the cavity is H2. Then H1≤50mm, H2≤50mm.

6. The manufacturing mold for the ultra-high voltage ultra-long narrow-angle ring as described in any one of claims 1-5, characterized in that: It also includes elastic straps that are wrapped around the outside of the inner and outer molds to secure them.

7. A manufacturing process for an ultra-high voltage ultra-long narrow-angle ring, characterized in that: Manufacturing the ultra-long narrow corner ring using the manufacturing mold as described in any one of claims 1-6 further includes the following steps: S1: Prepare wet paper by processing the wet paper into an arc-shaped paper strip according to the arc of the mold. S2: Mold preparation, cleaning the mold; S3: Lay the wet paper along the arc of the mold, and pat it flat by hand. The wet paper should not have any wrinkles. S4: Close the two angle steel pieces together and clamp them on the outside with several G-clamps. Use elastic straps to wrap and secure the mold gap area between adjacent G-clamps. S5: Place the whole thing in an oven to dry at a temperature of 110-115℃ for 6-8 hours. S6: After baking, demold, trim the edge excess, and process to the finished product size according to specifications.

8. The manufacturing process of the ultra-high voltage ultra-long narrow-angle ring as described in claim 7, characterized in that: The maximum arc length of the manufactured ultra-long narrow corner ring can be machined to 40% of the total circumference of the narrow corner ring. The arc of a single narrow corner ring can be machined to 140°-150°. The height h1 of the narrow corner ring can be machined to 8-40mm, and the width h2 of the narrow corner ring can be machined to 8-40mm, while satisfying H1>h1 and H2>h2.

9. The manufacturing process of the ultra-high voltage ultra-long narrow-angle ring as described in claim 8, characterized in that: The values ​​of H1-h1 are in the range of 10-15 mm, and the values ​​of H2-h2 are in the range of 10-15 mm.

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