A structure of a ceramic-sealed electrode for a titanium sublimator

Abstract

This invention belongs to the field of titanium sublimators, specifically a ceramic-sealed electrode structure for titanium sublimators. It includes a guide tube, a sealing flange, a cap, three conductive electrodes made of titanium-molybdenum wires, and a common electrode. The three conductive electrodes and the common electrode are arranged circumferentially along the cap and fixedly connected to it. The cap is fixed inside the sealing flange, and the guide tube is fixed to one side of the sealing flange. The conductive electrodes of the titanium-molybdenum wires include a titanium wire support rod, an upper cap, a ceramic tube, and a lower cap. The ceramic tube is connected to the upper and lower caps on both sides, respectively. The lower cap is fixed inside the cap. The titanium wire support rod passes through the upper cap, the ceramic tube, and the lower cap, and is fixedly connected to the upper cap. The common electrode includes a ground cap and a ground support rod. The ground cap is fixed inside the cap, and the ground support rod passes through the ground cap and is fixedly connected to it. This invention can prevent deformation of the ground support rod and titanium wire support rod caused by the heating of the titanium-molybdenum wires, avoiding poor contact with the power cable due to deformation of the titanium sublimator connector.

Description

Technical Field

[0001] This invention belongs to the field of titanium sublimators, specifically a ceramic-sealed electrode structure for titanium sublimators. Background Technology

[0002] Titanium sublimators are one of the main pump types for achieving clean ultra-high vacuum. Their main principle is to utilize the reactive gas properties of titanium to continuously or intermittently deposit a getter (titanium) onto the pump's suction surface to achieve the purpose of evacuation. The ceramic-sealed electrode is the core component of the titanium sublimator, and its structure and vacuum sealing performance are crucial indicators affecting the sublimator's quality. Currently, existing ceramic-sealed electrode structures use flanges and thick-walled plates welded together. When the titanium-molybdenum wire sublimates, the temperature of the titanium wire reaches over 1000℃. This heat is transferred through the sublimator electrode to the electrode plug, causing the plug to expand due to heat. This easily leads to poor contact at the electrode plug, resulting in malfunction and preventing the sublimator from operating normally. Therefore, optimizing the ceramic-sealed electrode structure is essential. Summary of the Invention

[0003] To avoid poor contact with the cable plug caused by thermal deformation of the titanium sublimator electrode plug, the present invention aims to provide a ceramic-sealed electrode structure for a titanium sublimator.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] This invention includes a guide tube, a sealing flange, a cap, three conductive electrodes of titanium-molybdenum wires, and a common electrode. The three conductive electrodes of titanium-molybdenum wires and the common electrode are arranged circumferentially along the cap and are respectively fixed to the cap. The cap is fixed inside the sealing flange, and the guide tube is fixed to one side of the sealing flange. The conductive electrodes of the titanium-molybdenum wires include titanium wire support rods, an upper cap, a ceramic tube, and a lower cap. The two sides of the ceramic tube are connected to the upper and lower caps respectively. The lower cap is fixed inside the cap. The titanium wire support rod passes through the upper cap, the ceramic tube, and the lower cap and is fixed to the upper cap. The common electrode includes a ground-level cap and a ground-level support rod. The ground-level cap is fixed inside the cap, and the ground-level support rod passes through the ground-level cap and is fixed to the ground-level cap. One end of the ground-level support rod and each titanium wire support rod is located on one side of the sealing flange, and the other end of the ground-level support rod and each titanium wire support rod is inserted into the guide tube located on the other side of the sealing flange.

[0006] Wherein: the upper cap, lower cap, subgrade cap and cover are all thin-walled structures, the upper cap has a wall thickness of 0.2-0.4 mm, the lower cap has a wall thickness of 0.2-0.4 mm, the subgrade cap has a wall thickness of 0.2-0.4 mm, and the cover has a wall thickness of 0.4-0.8 mm.

[0007] The verticality and coaxiality of the titanium wire support rod, ground support rod, cap, and sealing flange are all within 0.05mm.

[0008] The ceramic tube is brazed to the upper and lower caps on both sides, respectively. The lower cap is brazed to the inside of the cap, and the titanium wire support is brazed to the upper cap.

[0009] The brazing filler metal is silver-copper wire with a diameter of 0.5–0.8 mm. The amount of brazing filler metal is one ring between the upper cap and the ceramic tube, with the outer diameter of the filler ring being 0.6–0.8 times the outermost diameter of the upper cap. Another ring of brazing filler metal is placed between the ceramic tube and the lower cap, with the outer diameter of the filler ring being 0.6–0.8 times the outermost diameter of the lower cap. The brazing holding time is 0.4–0.6 hours, followed by furnace cooling.

[0010] The prefecture-level cap is brazed and fixed inside the cap, and the prefecture-level support rod is brazed and fixed to the prefecture-level cap.

[0011] The brazing filler material is silver-copper wire with a diameter of 0.5–0.8 mm. The amount of brazing filler material is one ring of filler material placed between the pre-level cap and the top cap. The outer diameter of the filler material ring is equal to 0.6–0.8 times the outermost diameter of the pre-level cap. The brazing holding time is 0.4–0.6 hours, followed by furnace cooling.

[0012] The upper cap, lower cap, ground level cap, cover, ground level support rod, and titanium wire support rod are all made of Kovar alloy.

[0013] The sealing flange has an annular groove on its surface facing the guide tube for positioning the guide tube.

[0014] The cap, which has three titanium-molybdenum wires as conductive electrodes and one common electrode, is fixed to the sealing flange by brazing and then fixed to the sealing flange by argon arc welding. The guide tube is fixed to the sealing flange by argon arc welding.

[0015] The advantages and positive effects of this invention are as follows:

[0016] 1. The upper cap, lower cap, ground cap, and cover of the present invention all adopt a thin-walled structure, which makes the electrode weldment have excellent thermal conductivity and can better release the deformation of the ground support rod and titanium wire support rod caused by the heating of titanium molybdenum wire, thus solving the problem of electrode joint deformation due to heat and poor contact of cable plug.

[0017] 2. The perpendicularity and coaxiality of the four support rods, cap and sealing flange of the present invention are within 0.05mm, ensuring good connection effect and greatly improving welding quality and yield. Attached Figure Description

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

[0019] Figure 2 for Figure 1 The right view;

[0020] Wherein: 1 is the guide tube, 2 is the sealing flange, 3 is the titanium wire support rod, 4 is the ground support rod, 5 is the ground cap, 6 is the lower cap, 7 is the cover cap, 8 is the ceramic tube, 9 is the upper cap, and 10 is the annular groove. Detailed Implementation

[0021] The invention will now be described in further detail with reference to the accompanying drawings.

[0022] For titanium sublimators, the superior structure of their core components (electrode weldments) is a crucial factor in ensuring their reliability and a necessary condition for producing high-quality titanium sublimators. Addressing the problems of poor contact at the joints and short-circuit malfunctions common in existing titanium sublimators, this invention designs a novel ceramic-sealed electrode structure, resolving the issues of electrode joint deformation due to heat and poor contact in the cable plug. The structure of this invention will now be further described.

[0023] like Figure 1 , Figure 2 As shown, the present invention includes a guide tube 1, a sealing flange 2, a cap 7, three conductive electrodes of titanium molybdenum wires and a common electrode. The three conductive electrodes of titanium molybdenum wires and the common electrode are evenly arranged along the circumference of the cap 7 and are fixedly connected to the cap 7 respectively. The cap 7 is fixedly connected to the inner hole of the sealing flange 2, and the guide tube 1 is fixedly connected to one side of the sealing flange 2.

[0024] The conductive electrode of the titanium-molybdenum wire in this embodiment includes a titanium wire support rod 3, an upper cap 9, a ceramic tube 8, and a lower cap 6. The two sides of the ceramic tube 8 are connected to the upper cap 9 and the lower cap 6, respectively. The lower cap 6 is fixed inside the cap 7. The titanium wire support rod 3 passes through the upper cap 9, the ceramic tube 8, and the lower cap 6, and is fixedly connected to the upper cap 9.

[0025] The common electrode in this embodiment includes a ground cap 5 and a ground support rod 4. The ground cap 5 is fixed inside the cap 7, and the ground support rod 4 passes through the ground cap 5 and is fixedly connected to the ground cap 5.

[0026] In this embodiment, the three titanium wire support rods 3 and the ground support rod 4 are parallel to each other. One end of the ground support rod 4 and each titanium wire support rod 3 is located on one side of the sealing flange 2, and the other end of the ground support rod 4 and each titanium wire support rod 3 is inserted into the guide tube 1 located on the other side of the sealing flange 2.

[0027] In this embodiment, four axial through holes are evenly opened on the cap 7 along the circumferential direction. The lower cap 6 is fixed in three of the through holes, and the ground cap 5 is fixed in the other through hole.

[0028] In this embodiment, the upper cap 9, lower cap 6, ground level cap 5, cover 7, ground level support rod 4, and titanium wire support rod 3 are all made of Kovar alloy, which has a coefficient of thermal expansion similar to that of ceramics and has good weldability.

[0029] In this embodiment, the sealing flange 2 has an annular groove 10 for positioning the guide tube 1 on its surface facing the guide tube 1. The sealing flange 2 is made of 304 stainless steel, which is commonly used in vacuum, and also has good weldability with Kovar alloy.

[0030] In this embodiment, the upper cap 9, lower cap 6, ground cap 5, and cover cap 7 are all thin-walled structures. The wall thickness of the upper cap 9 is 0.2–0.4 mm, the lower cap 6 is 0.2–0.4 mm, the ground cap 5 is 0.2–0.4 mm, and the cover cap 7 is 0.4–0.8 mm. This thin-walled structure provides excellent thermal conductivity for the ceramic-sealed electrode structure, effectively mitigating the heat deformation of the ground support rod 4 and titanium wire support rod 3 caused by the heating of the titanium molybdenum wire. This significantly avoids the problem of poor contact between the titanium sublimator connector and the power cable plug due to deformation.

[0031] The perpendicularity and coaxiality of the ground-level support rod 4, the three titanium wire support rods 3, the cap 7, and the sealing flange 2 in the electrode welding component directly affect the connection effect with the cable plug. Poor perpendicularity and coaxiality can easily lead to an overly tight connection, making installation difficult, and can also cause uneven stress on the titanium wire support rods 3, ground-level support rods 4, and guide tube 1. Under the dual influence of thermal stress, this can cause deformation of the titanium wire support rods 3 and ground-level support rods 4, easily leading to vacuum leakage at the brazing joint. In this embodiment, the perpendicularity and coaxiality of the titanium wire support rods 3, ground-level support rods 4, cap 7, and sealing flange 2 are all within 0.05mm, ensuring a good connection effect.

[0032] When brazing the ceramic sealing electrode, the amount of silver-copper solder and the welding holding time must be strictly controlled to avoid insufficient solder, which would prevent vacuum sealing; and excessive solder, which would reach the outer edge of the cap 7 and affect the argon arc welding with the sealing flange 2. In this embodiment, the two sides of the ceramic tube 8 are brazed and fixed to the upper cap 9 and the lower cap 6, respectively. The lower cap 6 is brazed and fixed inside the cap 7, and the titanium wire support rod 3 is brazed and fixed to the upper cap 9. The brazing solder is silver-copper wire solder with a diameter of 0.5-0.8 mm. The amount of solder used is as follows: a ring of solder is placed between the upper cap 9 and the ceramic tube 8, and the outer diameter of the solder ring is equal to 0.6-0.8 times the outermost diameter of the upper cap 9; a ring of solder is also placed between the ceramic tube 8 and the lower cap 6, and the outer diameter of the solder ring is equal to 0.6-0.8 times the outermost diameter of the lower cap 6. The brazing holding time is 0.4-0.6 hours, followed by furnace cooling. In this embodiment, the geostationary cap 5 is brazed and fixed inside the cap 7, and the geostationary support rod 4 is brazed and fixed to the geostationary cap 5. The brazing material is silver-copper wire brazing material with a diameter of 0.5-0.8 mm. The amount of brazing material is one ring of brazing material placed between the geostationary cap 5 and the cap 7, and the outer diameter of the brazing circle is equal to 0.6-0.8 times the outermost diameter of the geostationary cap 5. The brazing holding time is 0.4-0.6 hours, and the furnace is cooled.

[0033] In the manufacturing process of this invention, the upper cap 9, ceramic tube 8, lower cap 6, and titanium wire support rod 3 are installed sequentially to form the conducting electrode of three titanium-molybdenum wires; the grounding cap 5 and grounding support rod 4 are installed sequentially to form the common electrode; the ceramic tube 8 is used to isolate the conducting electrode and the common electrode; then, the three titanium-molybdenum wire conducting electrodes, one common electrode, and the cap 7 are installed together on the brazing fixture and brazed in the furnace; after brazing, they are argon-arc welded to the sealing flange 2 to form a vacuum seal with a vacuum leakage rate of less than 1×10E-8 Pa.L / s. Finally, it is argon-arc welded to the guide tube 1 to form a ceramic-sealed electrode.

[0034] The novel ceramic-sealed electrode structure described above can solve the problems of poor contact between the electrode joint and the cable plug due to thermal deformation. Moreover, it greatly improves the quality and yield of the ceramic-sealed electrode structure, providing a new structure and approach for optimizing the ceramic-sealed structure of titanium sublimators.

Claims

1. A ceramic-sealed electrode structure for a titanium sublimator, characterized in that: The system includes a guide tube (1), a sealing flange (2), a cap (7), three conductive electrodes of titanium-molybdenum wires, and a common electrode. The three conductive electrodes of titanium-molybdenum wires and the common electrode are arranged circumferentially around the cap (7) and are fixedly connected to the cap (7). The cap (7) is fixedly connected to the inside of the sealing flange (2). The guide tube (1) is fixedly connected to one side of the sealing flange (2). The conductive electrodes of the titanium-molybdenum wires include a titanium wire support rod (3), an upper cap (9), a ceramic tube (8), and a lower cap (6). The two sides of the ceramic tube (8) are connected to the upper cap (9) and the lower cap (6), respectively. The lower cap (6) is fixed to the cap. Inside the cap (7), the titanium wire support rod (3) passes through the upper cap (9), ceramic tube (8) and lower cap (6) and is fixedly connected to the upper cap (9); the common pole includes a ground cap (5) and a ground support rod (4), the ground cap (5) is fixed inside the cap (7), the ground support rod (4) passes through the ground cap (5) and is fixedly connected to the ground cap (5); one end of the ground support rod (4) and each titanium wire support rod (3) is located on one side of the sealing flange (2), and the other end of the ground support rod (4) and each titanium wire support rod (3) is inserted into the guide tube (1) located on the other side of the sealing flange (2); The upper cap (9), lower cap (6), subgrade cap (5), and cover (7) are all thin-walled structures. The wall thickness of the upper cap (9) is 0.2-0.4 mm, the wall thickness of the lower cap (6) is 0.2-0.4 mm, the wall thickness of the subgrade cap (5) is 0.2-0.4 mm, and the wall thickness of the cover (7) is 0.4-0.8 mm.

2. The ceramic-sealed electrode structure for a titanium sublimator according to claim 1, characterized in that: The verticality and coaxiality of the titanium wire support rod (3), the ground support rod (4), the cap (7) and the sealing flange (2) are all within 0.05mm.

3. The ceramic-sealed electrode structure for a titanium sublimator according to claim 1, characterized in that: The ceramic tube (8) is brazed to the upper cap (9) and the lower cap (6) on both sides respectively. The lower cap (6) is brazed to the cap (7) and the titanium wire support rod (3) is brazed to the upper cap (9).

4. The ceramic-sealed electrode structure for a titanium sublimator according to claim 3, characterized in that: The brazing material is silver-copper wire brazing material with a diameter of 0.5-0.8 mm. The brazing amount is one ring of brazing material placed between the upper cap (9) and the ceramic tube (8), with the outer diameter of the brazing circle equal to 0.6-0.8 times the outermost diameter of the upper cap (9). A ring of brazing material is placed between the ceramic tube (8) and the lower cap (6), with the outer diameter of the brazing circle equal to 0.6-0.8 times the outermost diameter of the lower cap (6). The brazing holding time is 0.4-0.6 hours, and the furnace is cooled.

5. The ceramic-sealed electrode structure for a titanium sublimator according to claim 1, characterized in that: The prefecture-level cap (5) is brazed and fixed inside the cap (7), and the prefecture-level support rod (4) is brazed and fixed to the prefecture-level cap (5).

6. The ceramic-sealed electrode structure for a titanium sublimator according to claim 5, characterized in that: The brazing material is silver-copper wire brazing material with a diameter of 0.5 to 0.8 mm. The amount of brazing material is one ring of brazing material placed between the pre-level cap (5) and the cap (7). The outer diameter of the brazing material ring is equal to 0.6 to 0.8 times the outermost diameter of the pre-level cap (5). The brazing holding time is 0.4 to 0.6 hours, and the furnace is cooled.

7. The ceramic-sealed electrode structure for a titanium sublimator according to claim 1, characterized in that: The materials of the upper cap (9), lower cap (6), ground level cap (5), cap (7), ground level support rod (4) and titanium wire support rod (3) are all Kovar alloy.

8. The ceramic-sealed electrode structure for a titanium sublimator according to claim 1, characterized in that: The sealing flange (2) has an annular groove (10) on its surface facing the guide tube (1) for positioning the guide tube (1).

9. The ceramic-sealed electrode structure for a titanium sublimator according to claim 1, characterized in that: The cap (7), which has three conductive electrodes and one common electrode of titanium molybdenum wires, is fixed to the sealing flange (2) by brazing and is fixed to the sealing flange (2) by argon arc welding. The guide tube (1) is fixed to the sealing flange (2) by argon arc welding.

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