Production process of metal inner liner vacuum tube with inverted flange

Abstract

The present invention provides a production process of an inverted flange metal liner vacuum tube, which belongs to the technical field of solar heat collecting tubes, and includes the following steps: an inverted flange pipe mouth is provided at one end of a glass outer tube; the outer edge of the end cover is heat-pressed and sealed with the inverted flange pipe mouth; the two ends of the metal liner are respectively sealed and connected with a head, one of which is provided with an opening; the tail end of the tube head is welded to the opening edge of the head; the outer wall of the tube head is welded to one end of a metal sealing bellows; the glass outer tube is sealed at the bottom, wherein a spring clip is fixedly installed on the bottom, and a getter is placed on the spring clip; the other end of the metal sealing bellows is welded to the end cover; exhaust is performed through the exhaust nozzle welded on the end cover to form a vacuum between the glass outer tube and the metal liner; the exhaust nozzle is sealed by step-by-step cooling; the vacuum tube is baked and the getter is evaporated to complete the process. The inverted flange metal liner vacuum tube produced by the invention has the characteristics of good sealing effect, convenient welding and high production efficiency.

Description

Technical Field

[0001] This invention provides a manufacturing process for an inward-turning flange metal inner liner vacuum tube, belonging to the field of solar collector tube technology. Background Technology

[0002] Solar energy is the most important basic energy source among various renewable energy sources. It boasts advantages such as abundant resources, inexhaustibility, and no environmental pollution or disruption of the ecological balance. Therefore, in today's world, with fossil fuels dwindling and the international energy situation becoming increasingly severe, developing and utilizing solar energy is one of the important ways to diversify energy supply and ensure energy security. Concentrator-type solar vacuum collectors can be applied in industrial heating and power generation, representing an important future development direction for the solar thermal industry. Their performance directly affects the speed of future solar thermal industry development.

[0003] Currently, there are three basic types of solar water heaters in my country: 1. All-glass vacuum tube solar water heaters; 2. Flat-plate water heaters; and 3. Confined solar water heaters. As buildings develop towards mid-rise and high-rise structures, low-rise buildings often feature pitched roofs, creating a challenge for the widespread adoption of integrated solar water heater designs. Existing solar vacuum collector tubes, whether double-glass tube or metal-tank type, are all single-opening and generally closed at the bottom. In actual production, due to technological limitations, this often results in poor sealing, complex manufacturing processes, and is time-consuming and labor-intensive. Summary of the Invention

[0004] The purpose of this invention is to provide a manufacturing process for inward-turning flange metal inner liner vacuum tubes that can overcome the above-mentioned defects. This process enables the produced inward-turning flange metal inner liner vacuum tubes to have good sealing effect, convenient welding, and high production efficiency.

[0005] To address the above problems, this invention provides a manufacturing process for an inward-flange metal inner vacuum tube. The inward-flange metal inner vacuum tube includes an end cap with a through hole, a metal sealing bellows, a metal inner liner, and a hollow glass outer tube. The manufacturing process includes the following steps:

[0006] I. One end of the outer glass tube is equipped with an inward-turned flange.

[0007] II. Heat-press the outer edge of the end cap to the inward flange pipe opening;

[0008] III. The metal inner liner is sealed at both ends with a cap, and one of the caps has an opening;

[0009] IV. Weld the end of the pipe head to the opening edge of the end cap;

[0010] V. The outer wall of the pipe head is welded to one end of the metal-sealed corrugated pipe;

[0011] VI. Seal the bottom of the glass outer tube, and fix the spring clips in place at the bottom, with getter placed on the spring clips;

[0012] VII. Weld the other end of the metal-sealed bellows to the end cap;

[0013] VIII. Exhaust air is released through the exhaust nozzle welded on the end cap, creating a vacuum between the glass outer tube and the metal inner liner;

[0014] IX. The exhaust nozzle is sealed using a stepped cooling system.

[0015] X. Sterilize the vacuum tube by baking and evaporate the getter to complete the process.

[0016] Preferably, the outer glass tube includes an outer glass tube I and an outer glass tube II. After the inward flange at one end of the outer glass tube I is heat-sealed with the end cap, the edge of the other end is fused with the edge of one end of the outer glass tube II.

[0017] Preferably, the sealing connection described in step III specifically includes: the convex surface of the end cap facing the inside of the metal inner liner; the inner wall of one end of the metal inner liner and the outer wall of the end cap are sealed by roller welding; and then the end cap is welded to the edge of the metal inner liner. Roller welding ensures water sealing and enhances pressure resistance, while welding along the edge ensures a vacuum inside the pipe.

[0018] Preferably, step IV specifically includes: the opening of the end cap is provided with a protruding welded part; the welded part is rolled and sealed to the outer wall of the pipe head tail end by a roller weld; the pipe diameter of the pipe head tail end is reduced twice during processing to form a boss; and the front end of the welded part is fused and welded to the side of the boss.

[0019] Preferably, step V specifically includes welding the long side of the J-type connecting ring to the outer wall of the pipe head, and connecting the short side of the J-type connecting ring to the edge of the metal-sealed corrugated pipe.

[0020] Preferably, the top of the tube head is provided with a bayonet and threads.

[0021] Preferably, the end cap is equipped with an vent before being heat-sealed with the inward flange port.

[0022] Preferably, step VIII specifically includes:

[0023] The inward-flange metal inner vacuum tube is placed inside the insulation box, while the end caps and tube heads are placed outside. The insulation box is evacuated at a temperature of 260-550℃ for 1-3 hours. The process continues until the vacuum level inside the tube reaches 5*10⁻⁶. -2 —5*10 - 4 After pa, the exhaust port is sealed after cooling.

[0024] Preferably, step VIII may further include: inserting an electric heating element into the metal inner tube; the temperature of the insulation box during vacuuming is 260-550℃, and the heating time is 1-3 hours; when the vacuum degree inside the tube reaches 5*10... -2 —5*10 -4 After pa, the exhaust port is sealed after cooling.

[0025] Preferably, step VIII may further include: covering the vacuum tube of the inner metal liner of the inverted flange with a reflective protective cover to prevent heat dissipation.

[0026] The integrated design of the flange and glass cover prevents intergranular corrosion at the weld seam caused by the internal medium, thus improving the lifespan and safety of the collector tubes. This solves the problems of collector tube bursting, difficulty in sealing, and easy leakage caused by existing sealing methods.

[0027] A supporting spring clip is installed on the metal inner liner, and a getter is placed on the supporting spring clip or the outer wall of the metal inner liner. The supporting spring clip supports the metal inner liner against the inner wall of the glass outer cover, and the getter is a barium-aluminum getter. The barium-aluminum getter ensures the heating and heat preservation functions of the heat collection tube. This invention uses supporting spring clips to support the glass outer cover and the metal inner liner. During storage and transportation, the end seal is subjected to external impact, and the supporting spring clips can effectively reduce the impact of external forces on the seal, while also avoiding problems caused by thermal expansion and contraction.

[0028] Preferably, the outer wall of the metal liner is coated with a selective heat-absorbing coating.

[0029] Preferably, the inner wall of the metal liner is provided with a metal layer or a non-metallic anti-corrosion material.

[0030] The beneficial effects achieved by this invention are:

[0031] This invention achieves a welded seal by connecting the boss of the pipe head to the welded part of the end cap, and by using a J-type connecting ring to weld the metal sealing bellows and the pipe head, ensuring a good sealing effect for the inward-turning flange metal inner liner vacuum tube, which is convenient to weld and has high production efficiency. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the present invention;

[0033] Figure 2 This is a partial enlarged view of part A of the present invention;

[0034] In the diagram: 1. End cap; 2. Metal-sealed bellows; 3. Metal inner liner; 4. Glass outer tube; 5. Inward-facing flange; 6. End cap; 7. Pipe head; 8. Welded part; 9. Boss; 10. J-type connecting ring; 11. Vent; 12. Spring clip. Detailed Implementation

[0035] Example 1

[0036] like Figure 1-2 As shown in the accompanying drawings, the present invention will be further described below: A manufacturing process for an inward-turning flange metal inner liner vacuum tube, wherein the inward-turning flange metal inner liner vacuum tube includes an end cap 1 with a through hole, a metal sealing bellows 2, a metal inner liner 3, and a hollow glass outer tube 4, the manufacturing process comprising the following steps:

[0037] I. One end of the outer glass tube 4 is equipped with an inward flange port 5;

[0038] II. Heat-press the outer edge of end cap 1 to the inward flange port 5;

[0039] III. The metal inner liner 3 is sealed at both ends to a cap 6, and one of the caps 6 has an opening;

[0040] IV. Weld the end of the pipe head 7 to the opening edge of the end cap 6;

[0041] V. The outer wall of the pipe head 7 is welded to one end of the metal-sealed corrugated pipe 2;

[0042] VI. Seal the bottom of the outer glass tube 4, and fix the spring clip 12 in the bottom seal, and place the getter on the spring clip;

[0043] VII. Weld the other end of the metal-sealed bellows 2 to the end cap 1;

[0044] VIII. Exhaust air is vented through the exhaust nozzle welded on the end cap 1, so that a vacuum is formed between the glass outer tube 4 and the metal inner liner 3.

[0045] IX. The exhaust nozzle is sealed using a stepped cooling system.

[0046] X. Sterilize the vacuum tube by baking and evaporate the getter to complete the process.

[0047] The outer glass tube 4 includes an outer glass tube I and an outer glass tube II. After the inner flange port 5 at one end of the outer glass tube I is heat-sealed with the end cap 1, the edge of the other end is fused with the edge of one end of the outer glass tube II.

[0048] The sealing connection described in step III specifically includes: the convex surface of the end cap facing the inside of the metal inner liner 3; the inner wall of one end of the metal inner liner 3 being sealed to the outer wall of the end cap 6 using a roller welding method; and then the end cap 6 being welded to the edge of the metal inner liner 3. The roller welding method ensures a water seal and enhances pressure resistance, while welding along the edge ensures a vacuum inside the pipe.

[0049] Step IV specifically includes the following: the opening of the end cap 6 is provided with a protruding welding part 8, the welding part 8 is rolled and sealed to the outer wall of the tail end of the pipe head 7, the diameter of the tail end of the pipe head 7 is reduced twice during processing to form a boss 9, and the front end of the welding part 8 is fused and welded to the side of the boss 9.

[0050] Step V specifically includes welding the long side of the J-type connecting ring 10 to the outer wall of the pipe head 7, and connecting the short side of the J-type connecting ring 10 to the edge of the metal-sealed bellows 2.

[0051] The top of the tube head 7 is equipped with a bayonet and threads.

[0052] The end cap 1 is equipped with an exhaust nozzle 11 before being heat-sealed with the inward flange port 5.

[0053] Step VIII specifically includes:

[0054] The inward-flange metal inner vacuum tube is placed inside the insulation box, while the end cap 1 and tube head 7 are placed outside. The insulation box is evacuated at a temperature of 260-550℃ for 1-3 hours. The process continues until the vacuum level inside the tube reaches 5*10⁻⁶. -2 —5*10 -4 After pa, the exhaust port is sealed after cooling.

[0055] Step VIII may further include: inserting an electric heating tube into the metal inner liner tube 3; the temperature of the insulation box during vacuuming is 260-550℃, and the heating time is 1-3 hours; when the vacuum degree inside the tube reaches 5*10... -2 —5*10 -4 After pa, the exhaust port is sealed after cooling.

[0056] Step VIII may also include: using a reflective protective cover to cover the vacuum tube inside the metal liner of the inverted flange to prevent heat dissipation.

Claims

1. A production process for an inverted flange metal liner vacuum tube, characterized in that: The inward-turned flange metal liner vacuum tube comprises an end cap (1) with a through hole, a metal sealing bellows (2), a metal liner (3) and a hollow glass outer tube (4), and its production process comprises the following steps: I. One end of the glass outer tube (4) is provided with an inverted flange pipe opening (5); II. Heat-pressing the outer edge of the end cover (1) and the inverted flange pipe opening (5); III. The two ends of the metal liner (3) are respectively sealed with a sealing head (6), and one of the sealing heads (6) is provided with an opening; IV. The tail end of the pipe head (7) is welded to the edge of the opening of the sealing head (6); V. The outer wall of the pipe head (7) is welded to one end of the metal sealing bellows (2); VI. The glass outer tube (4) is sealed at the bottom, wherein a spring clip (12) is fixedly installed at the bottom, and a getter is placed on the spring clip; VII. Welding the other end of the metal sealing bellows (2) to the end cover (1); VIII. Exhausting air through the exhaust nozzle welded on the end cover (1) to form a vacuum between the glass outer tube (4) and the metal inner liner (3); IX. Seal the exhaust nozzle by step-by-step cooling; X. Bake out the vacuum tube, evaporate the getter, and complete the process; The glass outer tube (4) comprises a glass outer tube I and a glass outer tube II. After the inverted flange tube opening (5) at one end of the glass outer tube I is heat-pressed and sealed with the end cover (1), the edge of the other end is welded to the edge of one end of the glass outer tube II. The sealing connection described in step III specifically includes: the convex surface of the head is facing the inside of the metal liner (3), the inner wall of one end of the metal liner (3) and the outer wall of the head (6) are sealed by roller welding, and then the head (6) and the edge of the metal liner (3) are welded, the roller welding is used to ensure water sealing and enhance pressure bearing capacity, and the welding along the edge is used to ensure vacuum in the tube; Step IV specifically includes: the opening of the sealing head (6) is provided with a protruding welding portion (8); the welding portion (8) is roller-welded and sealed with the outer wall of the rear end of the pipe head (7); the diameter of the rear end of the pipe head (7) is reduced twice during processing to form a boss (9); the front end of the welding portion (8) is fusion-welded with the side of the boss (9); Step V specifically includes: welding the outer wall of the pipe head (7) to the long side of the J-shaped connecting ring (10), and connecting the short side of the J-shaped connecting ring (10) to the edge of the metal sealing bellows (2).

2. The process for producing an inward-turned flange metal liner vacuum tube according to claim 1, characterized in that: The top of the pipe head (7) is provided with a bayonet and a thread.

3. The process for producing an inward-turned flange metal liner vacuum tube according to claim 1, characterized in that: The end cover (1) is provided with an exhaust nozzle (11) before being heat-pressed and sealed with the inward-turned flange pipe opening (5).

4. The process for producing an inward-turned flange metal liner vacuum tube according to claim 1, characterized in that: Step VIII specifically includes: Place the metal inner tube with inverted flange in an incubator, and place the end cap (1) and tube head (7) outside the incubator. When the incubator is evacuated, the temperature is 260-550°C, and the heating time is 1h-3h. When the vacuum degree in the tube reaches 5*10 -2 —5*10 -4 After pa, cool down and seal the exhaust nozzle.

5. The process for producing an inward-turned flange metal liner vacuum tube according to claim 4, characterized in that: Step VIII specifically includes: inserting an electric heating tube into the metal inner tube (3), the temperature of the insulated box is 260-550°C when the vacuum is evacuated, the heating time is 1h-3h, and when the vacuum degree in the tube reaches 5*10 -2 —5*10 -4 After pa, cool down and seal the exhaust nozzle.

6. The process for producing an inward-turned flange metal liner vacuum tube according to claim 1, characterized in that: Step VIII specifically also includes: using a reflective layer protective cover to cover the inward-turned flange metal inner vacuum tube to prevent heat dissipation.

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