WO2022048322A1

WO2022048322A1 - Vacuum switch tube for circuit breaker and method for manufacturing outer casing thereof

Info

Publication number: WO2022048322A1
Application number: PCT/CN2021/106396
Authority: WO
Inventors: 南寅; 刘万里; 沈迪; 任庆庆; 陈金枢; 余佳; 蒋志浩
Original assignee: 天津首瑞智能电气有限公司
Priority date: 2020-09-04
Filing date: 2021-07-15
Publication date: 2022-03-10
Also published as: CN111916303A; CN114342030A

Abstract

A vacuum switch tube for a circuit breaker and a manufacturing method for an outer casing thereof, which belong to the technical field of vacuum switch tubes. The vacuum switch tube for a circuit breaker comprises a casing body (1), a moving end assembly and a fixed end assembly, the casing body (1) comprises an outer insulated portion (11) and an inner insulated portion (12) arranged within the outer insulated portion (11), the fixed end assembly and the moving end assembly are both arranged within the outer insulated portion (11), the moving end assembly and the fixed end assembly establish mutual contact so as to implement an electrical pathway, and the moving end assembly and the fixed end assembly separate so as to implement an electrical open circuit; a sealed chamber usable for arc extinguishing is formed between the outer insulated portion (11), the inner insulated portion (12), the moving end assembly and the fixed end assembly, and by means of the arrangement of the inner insulated portion (12), creepage distance can be increased as much as possible, while also reducing the size of the vacuum switch tube to a relatively large extent, and consequently allowing manufacturing costs to be reduced.

Description

A vacuum switch tube for circuit breaker and method for making the same

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Chinese Patent Application No. 202010924361.0, which was filed on September 4, 2020, and is entitled "A Method for Making a Vacuum Switch for Circuit Breakers and Its Housing", the entire contents of which are incorporated herein by reference. .

technical field

The application belongs to the technical field of vacuum switch tubes, and in particular relates to a manufacturing method of a vacuum switch tube for circuit breakers and a casing thereof.

Background technique

Vacuum switch is a promising power switch. In recent years, the demand for medium-voltage vacuum switches has accounted for 70-80% of the total production in the world market. In addition, with the continuous improvement of the technical level, high-voltage and ultra-high-voltage vacuum switches are also being vigorously developed. The vacuum switch tube (also known as the vacuum interrupter) is the key component of the vacuum switch. People often call it the heart of the vacuum switch. Its design and manufacture has a history of more than 30 years in my country, and it has formed a domestic A team with the ability to research, develop, design and manufacture various types of vacuum switch tubes. At present, the vacuum switch tubes required for various vacuum switches have been widely used in various fields such as power system, petroleum, chemical industry, coal mine, metallurgy and electrified railway, which basically meet the needs of my country's national economic construction and development.

Most of the existing vacuum circuit breakers used in 3.6kV-40.5kV three-phase AC power systems use air as the insulating medium. (referred to as phase and ground) is not broken down by voltage, and sufficient air insulation distance must be ensured, while the vacuum interrupter is exposed to the air. Under the action of the electric field, the surface of the insulating shell of the vacuum interrupter is easy to accumulate dust, and the changes of ambient temperature and humidity are prone to condensation on the surface of the insulating shell of the vacuum interrupter. In order to avoid the adverse effects of dust and condensation on the insulation of the vacuum circuit breaker It is necessary to ensure that the insulating shell of the vacuum interrupter has sufficient height and the creepage distance along the surface of the shell, which will inevitably lead to an increase in the volume of the vacuum circuit breaker and the associated switchgear, and the volume of the vacuum interrupter is also larger and the cost is higher. .

SUMMARY OF THE INVENTION

1. Technical problems to be solved

In view of the problems existing in the prior art, the purpose of the present application is to provide a method for manufacturing a vacuum switch tube for circuit breaker and its casing, which can increase the creepage distance as much as possible through the setting of the inner insulating part, and at the same time, to a greater extent Therefore, the volume of the vacuum switch tube is reduced, thereby reducing the manufacturing cost.

2. Technical solutions

In order to solve the above-mentioned problems, the application adopts the following technical solutions:

A vacuum switch tube for a circuit breaker, comprising a casing, a moving end assembly and a static end assembly;

the housing includes an outer insulating part and an inner insulating part arranged in the outer insulating part;

The static end assembly and the moving end assembly are both arranged in the outer insulating part;

The moving end assembly and the static end assembly are in contact to realize an electrical path; the moving end assembly and the static end assembly are disengaged to realize an electrical open circuit;

A sealed chamber that can be used for arc extinguishing is formed between the outer insulating part, the inner insulating part, the moving end assembly and the static end assembly;

When the static end assembly is in contact with the moving end assembly, the creepage distance is the difference between the vertical height of the outer insulating part and the vertical height of the inner insulating part and the sum of the vertical height of the outer insulating part.

Further, the static end assembly includes a static conductive rod, a static end cover fixed on the outer side of the static conductive rod, and a static contact fixed on the upper end of the static conductive rod;

The movable end assembly includes a movable end cover, a fixed ring fixed on the upper end face of the movable end cover, a guide sleeve fixed inside the fixed ring, a movable conductive rod slidably connected to the inner side of the guide sleeve, and fixed on the lower end of the movable conductive rod. The movable contact and the bellows fixed between the inner top end of the movable end cover and the lower part of the movable conductive rod, the upper end surface of the movable conductive rod is higher than the upper end surface of the fixed ring.

Further, the static contact and the moving contact are both copper-chromium alloy materials.

Further, a shielding cover is fixed on the outer wall of the movable conductive rod close to the lower side, the upper end surface of the shielding cover is located between the bellows and the movable contact, and the lower end surface of the shielding cover is lower than the lower end surface of the static contact.

Further, the movable conductive rod, the movable end cover, the static conductive rod, the static end cover and the shielding cover are all conductive oxygen-free copper materials.

Further, the outer insulating portion and the inner insulating portion are both made of ceramic materials, and the outer insulating portion and the inner insulating portion are of an integrated structure, the outer insulating portion is in the shape of a straight tube, and the inner insulating portion is located at the outer portion of the outer insulating portion. At the non-central part, the upper end surface of the static end cover is fixed with the lower end surface of the inner insulating part, the lower end surface of the movable end cover is fixed with the upper end surface of the inner insulating part, and the lower end surface of the static conducting rod is insulated from the outer surface. The lower ends of the parts are flush.

Further, the outer insulating portion and the inner insulating portion are both made of ceramic materials, and the outer insulating portion and the inner insulating portion are of an integrated structure, the outer insulating portion is in the shape of a straight tube, and the inner insulating portion is located at the outer portion of the outer insulating portion. At the central part, the upper end surface of the static end cover is fixed with the lower end surface of the inner insulating part, the lower end surface of the movable end cover is fixed with the upper end surface of the inner insulating part, and the lower end surface of the static conducting rod is higher than the outer insulating part. lower end face of the part.

Further, the outer insulating part includes a hard insulator, a mounting groove opened on the inner wall of the hard insulator, and a soft insulator fixed on the inner wall of the installation groove, the inner insulating part is fixed on the inner wall of the soft insulator, the static The upper end face of the end cap is fixed with the lower end face of the inner insulating part, the lower end face of the movable end cap is fixed with the upper end face of the inner insulating part, the hard insulator is epoxy resin or thermoplastic material, and the soft insulator is Silica gel.

A vacuum switch tube for a circuit breaker, and a method for making the shell of the vacuum switch tube includes the following steps:

Step 1, ball milling, the alumina raw material and industrial paraffin are ground in a ball mill according to a certain proportion to obtain mixed powder;

Step 2, heating and stirring, pouring the mixed powder obtained in step 1 into a mixer for heating and stirring, the heating temperature is 80-90 °, and the mixed powder is gradually melted into a flowable mixed slurry;

Step 3, hot die casting, pour the slurry obtained in step 2 into the die casting machine, and use the pneumatic principle to extrude the mixed slurry into the mold to realize the molding of ceramic blanks to obtain blanks;

Step 4. Wax removal from the embryo, and discharge the paraffin in the embryo within a certain temperature range;

Step 5, high temperature sintering, the blanks after wax removal are placed in a bowl in an orderly manner, and then sintered in a high temperature kiln;

Step 6: Grinding the blanks, grinding the sharp edges and corners of the blanks sintered in step 5, and then processing the metallized surface to obtain a ceramic shell in the shape of a straight tube.

3. Beneficial effects

Compared with the prior art, the embodiments of the present application have some or all of the following advantages:

(1) This solution can increase the creepage distance as much as possible through the arrangement of the inner insulating part, and at the same time reduce the volume of the vacuum switch tube to a large extent, thereby reducing the manufacturing cost.

(2) Both the static contact and the moving contact are sealed in the sealed cavity, which has the function of waterproof and anti-oxidation, can work in extreme environments, and has strong environmental adaptability.

(3) Ceramics are used as the material of the arc extinguishing chamber. In the middle and later stages of the electrical life, the withstand voltage and insulation performance between the contacts is better than the products of the plastic arc extinguishing chamber. Under the same electrical life requirements, higher power loads can be switched on and off. , reliable performance.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic cross-sectional three-dimensional structure diagram of Embodiment 1 of the application;

FIG. 2 is a schematic three-dimensional structure diagram of a housing part of Embodiment 1 of the application;

3 is a schematic cross-sectional three-dimensional structure diagram of Embodiment 2 of the application;

FIG. 4 is a schematic three-dimensional structure diagram of the housing part of Embodiment 2 of the application;

5 is a schematic cross-sectional three-dimensional structure diagram of the housing, the static end assembly and the moving end assembly part of Embodiment 3 of the application;

FIG. 6 is a schematic cross-sectional structure diagram of a housing part of Embodiment 3 of the present application;

FIG. 7 is a schematic cross-sectional structure diagram of the outer insulating portion of Embodiment 3 of the present application;

8 is a schematic cross-sectional structure diagram of the soft insulator part of Example 3 of the application;

9 is a schematic three-dimensional structure diagram of the static conductive rod, the shielding cover and the movable conductive rod part of the embodiment 1, the embodiment 2 and the embodiment 3 of the application;

Fig. 10 is a schematic three-dimensional structure diagram of the static contact and the movable contact of Embodiment 1, Embodiment 2 and Embodiment 3 of the application when they are in contact and conducting.

Description of the labels in the figure:

1 shell, 11 outer insulating part, 111 hard insulator, 112 mounting groove, 113 soft insulator, 12 inner insulating part, 21 movable conductive rod, 22 guide sleeve, 23 fixed ring, 24 movable end cover, 25 bellows, 26 moving contacts, 31 static conductive rods, 32 static end caps, 33 static contacts, 4 shielding covers.

detailed description

The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, but not to limit the present application. It will be apparent to those skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating examples of the present application.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprises" does not preclude the presence of additional identical elements in a process, method, article, or device that includes the element.

Example 1:

Please refer to Figures 1-6 and 9-10 of a vacuum switch tube for circuit breakers, which includes a housing 1, a moving end assembly and a static end assembly.

The casing 1 includes an outer insulating portion 11 and an inner insulating portion 12 provided in the outer insulating portion 11 .

Both the static end assembly and the moving end assembly are arranged in the outer insulating portion 11 .

The static end assembly includes a static conductive rod 31 , a static end cover 32 fixed on the outer side of the static conductive rod 31 , and a static contact 33 fixed on the upper end of the static conductive rod 31 .

The movable end assembly includes a movable end cover 24 , a fixed ring 23 fixed on the upper end surface of the movable end cover 24 , a guide sleeve 22 fixed inside the fixed ring 23 , a movable conductive rod 21 slidably connected to the inner side of the guide sleeve 22 , The movable contact 26 at the lower end of the movable conductive rod 21 and the bellows 25 fixed between the inner top end of the movable end cover 24 and the lower part of the movable conductive rod 21 (the bellows 25 is a kind of elastic element, and the sidewall is wavy. The metal tube can be longitudinally stretched and stretched. Since the bellows 25 is introduced between the movable end cover 24 and the movable conductive rod 21, the outer insulating part 11 is completely sealed, and the movable conductive rod 21 can move vertically up and down. The sealing performance of the outer insulating portion 11 is destroyed), and the upper end surface of the movable conductive rod 21 is higher than the upper end surface of the fixed ring 23 .

A shielding cover 4 is fixed on the outer wall of the movable conductive rod 21 close to the lower side. The upper end surface of the shielding cover 4 is located between the bellows 25 and the movable contact 26. The lower end surface of the shielding cover 4 is lower than the lower end surface of the static contact 33. 4 is fixed by connecting with the movable conductive rod 21, which can effectively prevent the shielding cover 4 from contacting the outer insulating part 11, and can shield the static contact 33 and the movable contact 26 in the axial direction.

Both the static contact 33 and the moving contact 26 are made of copper-chromium alloy. The copper-chromium alloy not only has high strength and good shape, but also has excellent electrical conductivity, thermal conductivity and corrosion resistance.

The movable conductive rod 21, the movable end cover 24, the static conductive rod 31, the static end cover 32 and the shielding cover 4 are all oxygen-free copper materials with good electrical conductivity, oxygen-free copper has no hydrogen embrittlement phenomenon, high conductivity, processing performance and welding. Performance, corrosion resistance and low temperature performance are good.

A sealed chamber that can be used for arc extinguishing is formed between the outer insulating part 11 , the inner insulating part 12 , the moving end assembly and the static end assembly.

The movable end assembly and the static end assembly are in contact to realize the electrical connection. Specifically, the movable contact 26 is in contact with the static contact 33 to realize the electric connection.

The moving end assembly and the static end assembly are disengaged to realize an electrical open circuit, and the specific moving contact 26 is disengaged from the static contact 33 to realize an electrical open circuit.

The outer insulating portion 11 and the inner insulating portion 12 are both made of ceramic materials, and the outer insulating portion 11 and the inner insulating portion 12 are integral structures. At the location, the upper end face of the static end cover 32 is fixed with the lower end face of the inner insulating portion 12 , the lower end face of the movable end cover 24 is fixed with the upper end face of the inner insulating portion 12 , and the lower end face of the static conducting rod 31 and the outer insulating portion 11 . The bottom face is flush.

When the static end assembly is in contact with the moving end assembly, the creepage distance is the difference between the vertical height of the outer insulating part 11 and the vertical height of the inner insulating part 12 and the sum of the vertical height of the outer insulating part 11, which is the same as the vacuum switch tube of the prior art. Compared with the creepage distance (the creepage distance in the prior art is the height of the outer wall of the vacuum switch tube), the volume of the outer insulating part 11 is smaller when the creepage distance is equal, thereby reducing the assembly volume and saving Cost of production.

When the external force moves the movable conductive rod 21 upward, the movable contact 26 is separated from the static contact 33, and an electrical open circuit is formed. In this state, the bellows 25 is compressed, and the sealed chamber is still in a vacuum state. The external force makes the movable conductive rod 21 When moving down and returning to its original position, the moving contact 26 contacts the static contact 33, an electrical path is formed, and the bellows 25 returns to its original state. The creepage distance is the vertical height of the outer insulating part 11 and the vertical height of the inner insulating part 12. The sum of the difference and the vertical height of the outer insulating part 11 can increase the creepage distance as much as possible while reducing the volume of the outer insulating part 11. Through the setting of the inner insulating part 12, while increasing the creepage distance as much as possible, The volume of the vacuum switch tube is reduced to a certain extent, thereby reducing the manufacturing cost.

A vacuum switch tube for circuit breaker, the manufacturing method of its shell 1 is as follows: comprising the following steps:

Step 6: Grinding the blanks, grinding the sharp edges and corners of the blanks sintered in step 5, and then processing the metallized surface to obtain the ceramic shell 1 in the shape of a straight tube.

Example 2:

3-4, the outer insulating portion 11 and the inner insulating portion 12 are both made of ceramic materials, and the outer insulating portion 11 and the inner insulating portion 12 are integral structures, the outer insulating portion 11 is in the shape of a straight tube, and the inner insulating portion 12 is located at At the center of the outer insulating portion 11, the upper end surface of the static end cover 32 is fixed with the lower end surface of the inner insulating portion 12, the lower end surface of the movable end cover 24 is fixed with the upper end surface of the inner insulating portion 12, and the lower end surface of the static conductive rod 31 is fixed. higher than the lower end surface of the outer insulating portion 11 .

The creepage distance is the difference between the vertical height of the outer insulating portion 11 and the vertical height of the inner insulating portion 12 and the sum of the vertical height of the outer insulating portion 11 .

Example 3:

Please refer to FIGS. 5-8 , the outer insulating portion 11 includes a rigid insulator 111 , an installation groove 14 formed on the inner wall of the rigid insulator 111 , and a soft insulator 113 fixed on the inner wall of the installation groove 14 , and the inner insulating portion 12 is fixed on the soft insulator 113 . The inner wall of the material insulator 113, the upper end surface of the static end cover 32 is fixed with the lower end surface of the inner insulating part 12, the lower end surface of the movable end cover 24 is fixed with the upper end surface of the inner insulating part 12, the rigid insulator 111 is epoxy resin or thermoplastic material , the soft insulator 113 is silica gel, the soft insulator 113 is used to buffer the force between the hard insulator 111 and the inner insulating part 12, and can make the sealing between the hard insulator 111 and the inner insulating part 12 better ( It is not easy for the arc to break down from the contact surface of the two).

Example 4:

Step 1. Grinding alumina raw material and industrial paraffin in a ball mill in a certain proportion to obtain mixed powder;

Step 2, making the mixed powder into a straight tube-shaped ceramic by isostatic pressing;

In step 3, the casing 1 is obtained by performing a rotary cutting operation on the central part of the straight-tube-shaped ceramic.

Example 5:

The outer insulating portion 11 and the inner insulating portion 12 are both made of ceramic materials, and the outer insulating portion 11 and the inner insulating portion 12 are integral structures. The outer insulating portion 11 is in the shape of a straight tube, and the inner insulating portion 12 is located at the center of the outer insulating portion 11 The upper end surface of the static end cover 32 is fixed with the lower end surface of the inner insulating portion 12 , the lower end surface of the movable end cover 24 is fixed with the upper end surface of the inner insulating portion 12 , and the lower end surface of the static conducting rod 31 is higher than the outer insulating portion 11 . lower end face.

The manufacturing method of the shell 1 includes the following steps:

Those skilled in the art should understand that the above-mentioned embodiments are all illustrative and not restrictive. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Those skilled in the art should be able to understand and implement other variant embodiments of the disclosed embodiments on the basis of studying the drawings, the description and the claims. In the claims, the term "comprising" does not exclude other means or steps; an item is intended to include one/one or more/kinds of items when not modified by a quantifier, and may be combined with "one/one or more/kinds of items" "Used interchangeably"; the terms "first", "second" are used to designate names and not to indicate any particular order. Any reference signs in the claims should not be construed as limiting the scope of protection. The functions of multiple parts appearing in the claims can be realized by a single hardware or software module. The appearance of certain technical features in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.

Claims

A vacuum switch tube for a circuit breaker, comprising a casing (1), a moving end assembly and a static end assembly, wherein,

The housing (1) includes an outer insulating portion (11) and an inner insulating portion (12) provided in the outer insulating portion (11);

Both the static end assembly and the moving end assembly are arranged in the outer insulating portion (11);

The moving end assembly and the static end assembly are in contact to realize an electrical path, and the moving end assembly and the static end assembly are disengaged to realize an electrical open circuit;

A sealed chamber that can be used for arc extinguishing is formed between the outer insulating part (11), the inner insulating part (12), the moving end assembly and the static end assembly;

When the static end assembly is in contact with the moving end assembly, the creepage distance is the difference between the vertical height of the outer insulating part (11) and the vertical height of the inner insulating part (12) and the outer insulating part (12). 11) and the sum of the vertical heights.
The vacuum switch tube for circuit breaker according to claim 1, wherein the static end assembly comprises a static conducting rod (31), a static end cover (32) fixed on the outer side of the static conducting rod (31), and a fixed a static contact (33) on the upper end of the static conductive rod (31);

The movable end assembly includes a movable end cover (24), a fixing ring (23) fixed on the upper end surface of the movable end cover (24), and a guide sleeve (22) fixed inside the fixing ring (23) , a movable conductive rod (21) slidably connected to the inner side of the guide sleeve (22), a movable contact (26) fixed on the lower end of the movable conductive rod (21), and a movable end cover (26) fixed on the lower end of the movable conductive rod (21). 24) The bellows (25) between the inner top end and the lower part of the movable conductive rod (21), the upper end surface of the movable conductive rod (21) is higher than the upper end surface of the fixed ring (23).
The vacuum switch tube for circuit breaker according to claim 2, wherein the static contact (33) and the moving contact (26) are both copper-chromium alloy materials.
The vacuum switch tube for circuit breaker according to claim 2, wherein a shielding cover (4) is fixed on the outer wall of the movable conductive rod (21) close to the lower side, and the upper end surface of the shielding cover (4) is located on the corrugated Between the tube (25) and the movable contact (26), the lower end surface of the shielding cover (4) is lower than the lower end surface of the static contact (33).
The vacuum switch tube for circuit breaker according to claim 4, wherein the movable conductive rod (21), the movable end cover (24), the static conductive rod (31), and the static end cover (32) Both the shielding cover (4) are made of conductive oxygen-free copper material.
The vacuum switch tube for circuit breaker according to claim 2, wherein the outer insulating part (11) and the inner insulating part (12) are both ceramic materials, and the outer insulating part (11) and the inner insulating part (11) are made of ceramic material. The insulating portion (12) has an integral structure, the outer insulating portion (11) is in the shape of a straight pipe, the inner insulating portion (12) is located at a non-central part of the outer insulating portion (11), and the static end The upper end face of the cover (32) is fixed with the lower end face of the inner insulating portion (12), the lower end face of the movable end cover (24) is fixed with the upper end face of the inner insulating portion (12), and the static electricity The lower end surface of the rod (31) is flush with the lower end surface of the outer insulating portion (11).
The vacuum switch tube for circuit breaker according to claim 2, wherein the outer insulating part (11) and the inner insulating part (12) are both ceramic materials, and the outer insulating part (11) and the inner insulating part (11) are made of ceramic material. The insulating portion (12) has an integral structure, the outer insulating portion (11) is in the shape of a straight pipe, the inner insulating portion (12) is located at the center of the outer insulating portion (11), and the static end cover The upper end surface of (32) is fixed with the lower end surface of the inner insulating part (12), the lower end surface of the movable end cover (24) is fixed with the upper end surface of the inner insulating part (12), and the static conducting rod The lower end surface of (31) is higher than the lower end surface of the outer insulating portion (11).
The vacuum switch tube for a circuit breaker according to claim 2, wherein the outer insulating part (11) comprises a rigid insulator (111), a mounting groove (14) opened on the inner wall of the rigid insulator (111), and a solid insulator (111). A soft insulator (113) disposed on the inner wall of the installation groove (14), the inner insulating portion (12) is fixed on the inner wall of the soft insulator (113), and the upper end surface of the static end cover (32) It is fixed with the lower end surface of the inner insulating part (12), the lower end surface of the movable end cover (24) is fixed with the upper end surface of the inner insulating part (12), and the rigid insulator (111) is epoxy resin. resin or thermoplastic material, and the soft insulator (113) is silica gel.
The vacuum switch tube for circuit breaker according to any one of claims 6 or 7, wherein the manufacturing method of the casing (1) comprises the following steps:

Step 1, ball milling, the alumina raw material and industrial paraffin are ground in a ball mill according to a certain proportion to obtain mixed powder;

Step 2, heating and stirring, pouring the mixed powder obtained in step 1 into a mixer for heating and stirring, the heating temperature is 80-90 °, and the mixed powder is gradually melted into a flowable mixed slurry;

Step 3, hot die casting, pour the slurry obtained in step 2 into the die casting machine, and use the pneumatic principle to extrude the mixed slurry into the mold to realize the molding of ceramic blanks to obtain blanks;

Step 4. Wax removal from the embryo, and discharge the paraffin in the embryo within a certain temperature range;

Step 5, high temperature sintering, the blanks after wax removal are placed in a bowl in an orderly manner, and then sintered in a high temperature kiln;

Step 6: Grinding the blanks, grinding the sharp edges and corners of the blanks sintered in step 5, and then performing metallized surface treatment to obtain a ceramic shell (1) in the shape of a straight tube.
The vacuum switch tube for circuit breaker according to any one of claims 6 or 7, wherein the manufacturing method of the casing (1) comprises the following steps:

Step 1. Grinding alumina raw material and industrial paraffin in a ball mill in a certain proportion to obtain mixed powder;

Step 2, making the mixed powder into a straight tube-shaped ceramic by isostatic pressing;

In step 3, the casing (1) is prepared by performing a rotary cutting operation on the central part of the straight-tube-shaped ceramic.