Gas circuit insulator and method for manufacturing the same

Abstract

The present invention discloses a gas path insulator and a manufacturing method thereof; wherein the gas path insulator comprises a main insulator made of ceramic, A ceramic tube plugs and B ceramic tube plugs alternately arranged inside the main insulator, and upper and lower end caps for pressing the A ceramic tube plugs and the B ceramic tube plugs in the main insulator are respectively arranged at the upper and lower ends of the main insulator. When a given voltage is applied to both ends of the gas path insulator, the tortuous gas channel reduces the voltage on the gas per unit length. At the same time, due to the slender and curved channel, the electrons will collide with the channel wall after a very short distance, and cannot obtain enough energy to ionize the gas molecules; under the combined effect of the above two factors, the gas path insulator of the present invention can not only ensure the circulation of gas, but also play the role of electrical insulation.

Description

Technical Field

[0001] The present invention relates to the technical field of gas discharge, and in particular to a gas path insulator and a manufacturing method thereof. Background Art

[0002] The electric propulsion system of a spacecraft burns inert gas to generate thrust. The tank storing inert gas is often not at the same potential as the thrust unit. This requires that the electrical insulation between the thrust unit and the tank be ensured while supplying a certain flow rate of gas to the thrust unit. Usually, there is a potential difference of up to several hundred volts to several thousand volts between the thrust unit and the tank. Even if a non-conductive gas pipeline such as a plastic pipe or a ceramic pipe is used, the gas in the pipeline will also undergo gas breakdown and discharge under the action of high voltage. Once the gas in the pipeline breaks down, a high-density plasma is generated in the pipeline, and the thrust unit and the tank are essentially in a short-circuit or semi-short-circuit state, causing the thrust unit to fail to work normally or even the entire spacecraft to be paralyzed. The role of the gas path insulator is to prevent gas breakdown and discharge while ensuring the gas supply, thereby playing the role of electrical insulation. Electric thrusters at home and abroad all use gas path electrical insulators of different structures to achieve gas path electrical isolation. For example, the XIPS-25 and NSTAR-30 ion thrusters of the United States use gas path electrical insulators with multi-stage segmented structures, and the 40cm ion thrusters of the NEXT program of the United States use porous gas path insulators filled with tiny spherical alumina ceramic particles. However, the existing gas path insulators are prone to structural failure under the conditions of ensuring the given working voltage and gas flow rate of the thruster. Summary of the invention

[0003] Based on the deficiencies of the prior art, the present invention discloses a gas path insulator with a firm structure and easy manufacturing, which can not only ensure that the thruster does not suffer structural failure under given working voltage, gas flow rate and other conditions, but also reliably suppress gas breakdown discharge.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a gas path insulator, comprising a main insulator made of ceramic, A ceramic tube plugs and B ceramic tube plugs alternately arranged inside the main insulator, and upper and lower end covers for pressing A ceramic tube plugs and B ceramic tube plugs tightly inside the main insulator are respectively arranged at the upper and lower ends of the main insulator.

[0005] As a further description of the above technical solution:

[0006] The upper end cover and the lower end cover are respectively connected to the main insulator by ceramic-metal sealing technology to achieve airtight connection, and the A ceramic tube plug and the B ceramic tube plug are laminated and pressed tightly into the main insulator.

[0007] As a further description of the above technical solution:

[0008] The other ends of the upper end cover and the lower end cover are provided with appropriate pipe joints according to use requirements, so as to be connected with the pipes of the gas circuit.

[0009] As a further description of the above technical solution:

[0010] The upper end cover and the lower end cover are both made of metal material.

[0011] As a further description of the above technical solution:

[0012] The A ceramic tube plug and the B ceramic tube plug are both made of ceramic materials.

[0013] As a further description of the above technical solution:

[0014] One side of the A ceramic tube plug and the B ceramic tube plug is engraved with a groove, and the other side thereof is a plane.

[0015] As a further description of the above technical solution:

[0016] The channel surface of the A ceramic tube plug contacts the plane of the B ceramic tube plug, and the channel surface of the B ceramic tube plug contacts the plane of the A ceramic tube plug.

[0017] As a further description of the above technical solution:

[0018] A first vent hole is provided at the center of the A ceramic tube plug.

[0019] As a further description of the above technical solution:

[0020] A second vent hole is provided at the edge of the B ceramic tube plug.

[0021] As a further description of the above technical solution:

[0022] The A ceramic tube plug and the B ceramic tube plug are alternately stacked in the order of ...ABABA... After stacking, the channel surface of any ceramic tube plug fits with the plane of the other ceramic tube plug to form a gas channel. The number of stacking layers is determined by the operating voltage. When the A ceramic tube plug and the B ceramic tube plug are alternately stacked, the first vent hole, the second vent hole and the channel and the inner wall of the main insulator together form a slender and tortuous gas channel.

[0023] A method for manufacturing the above-mentioned gas circuit insulator comprises the following steps:

[0024] (1) The main insulating ceramic tube 1 is ground into the required size and then subjected to ceramic metallization treatment;

[0025] (2) After grinding and polishing the upper and lower surfaces and the side surfaces of the A ceramic tube plug and the B ceramic tube plug, a first vent hole and a second vent hole are respectively punched in the center and the edge, and then the grooves of the A ceramic tube plug and the B ceramic tube plug are pressed into shape by a mold when the ceramic blank is pressed;

[0026] (3) Assemble the upper and lower end covers, the main insulator and the pipe plug together, place solder at the sealing part and fix them in the brazing fixture, and complete the brazing according to the brazing process.

[0027] The present invention has the following beneficial effects:

[0028] When a given voltage is applied to both ends of the gas path insulator, the tortuous gas channel reduces the voltage on the gas per unit length. At the same time, since the channel is slender and curved, electrons will collide with the channel wall after moving a very short distance and cannot obtain sufficient energy to ionize the gas molecules. Under the combined effect of the above two factors, the gas path insulator of the present invention can not only ensure the circulation of gas, but also play a role in electrical insulation.

[0029] From a manufacturing perspective, the gas path insulator of the present invention can adopt mature ceramic materials and ceramic-metal sealing technology, with low process difficulty and high strength, and can withstand the thermal shock and force shock required by spacecraft applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a gas path insulator disclosed in the present invention;

[0031] Figure 2 A is a schematic diagram of the structure of a ceramic tube plug;

[0032] Figure 3 It is a schematic diagram of the structure of the ceramic tube plug B;

[0033] Figure 4 A schematic diagram of an example structure disclosed in the present invention;

[0034] Figure 5 It is a schematic diagram of an example structure of a ceramic tube plug A disclosed in the present invention;

[0035] Figure 6 This is a schematic diagram of the structure of an example of the B ceramic tube plug disclosed in the present invention.

[0036] Reference numerals:

[0037] 1-main insulating ceramic tube; 2-A ceramic tube plug; 3-B ceramic tube plug; 4-upper end cover; 5-lower end cover; 6-channel; 7-first vent hole; 8-second vent hole. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Reference Figure 1-3 , a gas path insulator, comprising a main insulator 1 made of ceramic, A ceramic tube plugs 2 and B ceramic tube plugs 3 alternately arranged inside the main insulator, the upper and lower ends of the main insulator 1 are respectively provided with upper and lower end caps for pressing the A ceramic tube plugs 2 and the B ceramic tube plugs 3 in the main insulator 1; the upper end cap 4 and the lower end cap 5 are respectively connected to the main insulator 1 by ceramic-metal sealing technology to achieve airtight connection, and the A ceramic tube plugs 2 and the B ceramic tube plugs 3 are laminated and pressed in the main insulator 1; the other ends of the upper end cap 4 and the lower end cap 5 are provided with suitable The invention relates to a pipe joint for connecting with the pipe of the gas circuit; the upper end cover 4 and the lower end cover 5 are both made of metal materials; the A ceramic tube plug 2 and the B ceramic tube plug 3 are both made of ceramic materials; one side of the A ceramic tube plug 2 and the B ceramic tube plug 3 is engraved with a groove, and the other side is a plane; the groove surface of the A ceramic tube plug 2 is in contact with the plane of the B ceramic tube plug 3, and the groove surface of the B ceramic tube plug 3 is in contact with the plane of the A ceramic tube plug 2; a first air vent 7 is provided in the center of the A ceramic tube plug 2; a second air vent 8 is provided at the edge of the B ceramic tube plug 3.

[0041] In this embodiment, the A ceramic tube plug 2 and the B ceramic tube plug 3 are alternately stacked in the order of ...A2B3A2B3A2... After stacking, the channel surface of any ceramic tube plug fits with the plane of another ceramic tube plug to form a gas channel. The number of stacking layers is determined by the operating voltage. When the A ceramic tube plug 2 and the B ceramic tube plug 3 are alternately stacked, the first vent 7, the second vent 8, the channel 6 and the inner wall of the main insulator 1 together form a slender and tortuous gas channel.

[0042] A method for manufacturing the above-mentioned gas circuit insulator comprises the following steps:

[0043] (1) The main insulating ceramic tube 1 is ground into the required size and then subjected to ceramic metallization treatment;

[0044] (2) After grinding and polishing the upper and lower surfaces and the side surfaces of the A ceramic tube plug 2 and the B ceramic tube plug 3, a first vent hole 7 and a second vent hole 8 are respectively punched in the center and the edge, and then the grooves of the A ceramic tube plug 2 and the B ceramic tube plug 3 are pressed into shape by a mold when the ceramic blank is pressed;

[0045] (3) Assemble the upper and lower end covers, the main insulator and the pipe plug together, place solder at the sealing part and fix them in the brazing fixture, and complete the brazing according to the brazing process.

[0046] Example

[0047] like Figure 4-6 As shown, the gas path insulator of this example is composed of a main insulating ceramic tube 1, two A ceramic tube plugs 2, one B ceramic tube plug 3, an upper end cover 4 and a lower end cover 5. The specific structure is: the gas path insulator is composed of a main insulator 1 made of ceramic and two metal end covers 4 and 5, which are formed into a vacuum sealed container with gas path connection joints at both ends through ceramic-metal sealing technology, and two A ceramic tube plugs 2 and one B ceramic tube plug 3 are pressed by the end covers in the order of A ceramic tube plug-B ceramic tube plug-A ceramic tube plug inside the main insulator 1. The first vent hole 7 of the A ceramic tube plug 2, the channel 6, the second vent hole 8 of the B ceramic tube plug 3, the gap between the chamfers of the A ceramic tube plug and the B ceramic tube plug and the inner wall of the main insulator 1 constitute a gas flow channel.

[0048] The manufacturing process of this example is as follows: the main insulating ceramic tube 1 is ground into the required size and then subjected to ceramic metallization treatment; the upper and lower surfaces and sides of the A ceramic tube plug and the B ceramic tube plug are ground and polished, and the first vent hole 7 and the second vent hole 8 are respectively punched in the center and the edge; the channels of the A and B ceramic tube plugs are pressed and formed by the mold when the ceramic blank is pressed. Figure 5 As shown in the figure, the end cover, the main insulator and the pipe plug are assembled together, and after solder is placed at the sealing position, they are fixed in a brazing fixture, and brazing is completed according to the brazing process.

[0049] The manufacturing process of the gas circuit insulator in this example is simple. The pipe plug and the main insulator porcelain tube can be made of ceramic materials with the same composition and sintering process, and have the same thermal expansion coefficient, which can ensure the good temperature shock resistance of the gas circuit insulator. The ceramic-metal sealing process is mature and the sealing parts have high mechanical strength. Therefore, the gas circuit insulator in this example meets the use requirements of the electric thruster.

[0050] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas circuit insulator, characterized in that: The invention comprises a main insulator made of ceramic, and ceramic tube plugs A and B alternately arranged inside the main insulator. The upper and lower ends of the main insulator are respectively provided with upper and lower end covers for pressing ceramic tube plugs A and B in the main insulator. The upper end cover and the lower end cover are respectively sealed with the main insulator by ceramic-metal sealing technology. One side of ceramic tube plugs A and B is engraved with a groove, and the other side is a plane. The groove surface of ceramic tube plug A contacts the plane of ceramic tube plug B, and the groove surface of ceramic tube plug B contacts the plane of ceramic tube plug A. A first vent is arranged at the center of ceramic tube plug A; a second vent is arranged at the edge of ceramic tube plug B. Ceramic tube plugs A and B are alternately overlapped in the order of ...ABABA... After overlap, the first vent, the second vent, the groove and the inner wall of the main insulator together form a slender and tortuous gas passage.

2. The gas circuit insulator according to claim 1, characterized in that: The other ends of the upper end cover and the lower end cover are provided with pipeline joints for connecting with pipelines of the gas circuit.

3. The gas circuit insulator according to claim 2, characterized in that: The upper end cover and the lower end cover are both made of metal material.

4. A method for manufacturing a gas circuit insulator according to any one of claims 1 to 3, characterized in that: The steps include: (1) Grind the main insulating ceramic tube into the required size and then perform ceramic metallization treatment; (2) After grinding and polishing the upper and lower surfaces and the side surfaces of the A ceramic tube plug and the B ceramic tube plug, a first vent hole and a second vent hole are respectively punched in the center and the edge, and then the grooves of the A ceramic tube plug and the B ceramic tube plug are pressed into shape by a mold when the ceramic blank is pressed; (3) Assemble the upper and lower end covers, the main insulator and the pipe plug together, place solder at the sealing part and fix them in the brazing fixture, and complete the brazing according to the brazing process.

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