Vacuum glass window assembly and design method thereof

Abstract

The invention provides a vacuum glass window assembly which is used for a vacuum container with a non-circular opening and comprises an adapter flange used for being installed on the non-circular opening of the vacuum container, and the shape of the adapter flange is designed to be matched with the shape of the non-circular opening of the vacuum container so as to cover the non-circular opening; the round welding neck flange is mounted on the adapter flange, a window is formed in the welding neck flange, the welding neck flange is provided with a glass mounting seat surrounding the window, and a mounting surface is arranged on the glass mounting seat; the annular glass gland is mounted on the glass mounting seat of the welding neck flange; the vacuum glass is mounted between the mounting surface of the glass mounting seat of the welding neck flange and the glass gland; and the protection plate is mounted on the glass gland so as to cover the vacuum glass. According to the vacuum glass window assembly provided by the invention, the safety problem of mounting the vacuum glass on the non-circular window of the vacuum container can be solved, and the sealing of the vacuum chamber under high vacuum is met.

Description

Technical Field

[0001] The invention belongs to the technical field of vacuum component design, and relates to a vacuum glass window component under high vacuum and a design method thereof. Background Art

[0002] The vacuum test chamber used to simulate the vacuum environment of space is often used for optical tests, temperature tests, etc. on the basis of vacuum conditions. The vacuum glass window assembly is a functional component that combines various vacuum components. It is usually used to observe the internal conditions of the vacuum container or as an optical test window. Its use on vacuum containers is essential.

[0003] The vacuum glass window assembly must not only meet the optical light transmission requirements, but also be able to withstand a certain vacuum pressure to ensure no damage and airtightness. Therefore, the design of vacuum components is a means to ensure the product quality, engineering quality and reliability of important tasks of vacuum equipment. At present, the vacuum windows used on vacuum containers are usually circular, and all kinds of vacuum design manuals also specify circular windows. In consideration of pressure bearing capacity, the light aperture of the window generally does not exceed DN200.

[0004] However, under certain special experimental conditions, in order to be compatible with optical experimental equipment, the window of the vacuum test chamber must be non-circular and large in size, such as a square window with a side length of 200mm-500mm. The square window needs to be matched with square vacuum glass. However, the processing technology of square vacuum glass is very complicated and costly. The glass is unevenly stressed and extremely easy to deform and break, and its safety is poor. If the square vacuum glass is to meet the safety requirements, the thickness of the glass can only be increased. However, the thickness of the glass affects the transmittance of the glass. The thicker the glass, the worse the transmittance, which can easily affect its use. Therefore, it is difficult to take into account both the safety and transmittance of square vacuum glass, and the practicality and safety of subsequent use cannot be improved at the same time. Summary of the invention

[0005] The purpose of the present invention is to provide a vacuum glass window assembly to solve the above problems and to solve the safety problem of installing vacuum glass on a non-circular window of a vacuum container.

[0006] The present invention provides a vacuum glass window assembly for a vacuum container having a non-circular opening, the vacuum glass window assembly comprising:

[0007] An adapter flange has a circular through hole in the middle, and the adapter flange is used to be installed on the non-circular opening of the vacuum container. The shape of the adapter flange is designed to match the shape of the non-circular opening of the vacuum container so as to cover the non-circular opening;

[0008] A circular high-neck flange is mounted on the adapter flange, the high-neck flange is provided with a window, and has a glass mounting seat surrounding the window, and the glass mounting seat has a mounting surface;

[0009] The annular glass gland is installed on the glass mounting seat of the high neck flange;

[0010] The vacuum glass is installed between the mounting surface of the glass mounting seat of the high-neck flange and the glass gland. The high vacuum seal between the vacuum glass and the high-neck flange is achieved by using the O-type vacuum glass sealing ring on the mounting surface. The glass mounting seat and the glass gland are connected by fastening bolts, so that the vacuum glass is pressed between the glass mounting seat and the glass gland.

[0011] A protective plate is installed on the glass cover to cover the vacuum glass.

[0012] According to at least one embodiment of the present application, the thickness of the vacuum glass is determined according to the allowable stress of the vacuum glass, the center distance of the vacuum glass sealing ring, and the safety factor.

[0013] According to at least one embodiment of the present application, the adapter flange is square.

[0014] According to at least one embodiment of the present application, the surface where the adapter flange contacts the vacuum container is a plane, and the portion where the vacuum container contacts the adapter flange has a sealing ring groove for accommodating the sealing ring.

[0015] According to at least one embodiment of the present application, the adapter flange is compressed and connected to the vacuum container by bolts, and a sealing ring is used to seal the adapter flange and the vacuum container.

[0016] According to at least one embodiment of the present application, the high neck flange is connected to the high neck flange by argon arc welding.

[0017] According to at least one embodiment of the present application, the length of the neck tube of the high-neck flange is one third to two thirds of the diameter of the window of the high-neck flange.

[0018] According to at least one embodiment of the present application, the neck tube length of the high-neck flange is 150 mm or 250 mm.

[0019] The present application also provides a vacuum container comprising the vacuum glass window assembly.

[0020] The present application also provides a design method for the above-mentioned vacuum glass window assembly, comprising:

[0021] S1: Determine the thickness of the vacuum glass according to the allowable stress of the vacuum glass, the center distance of the vacuum glass sealing ring, and the safety factor;

[0022] S2: Calculate the center stress of the vacuum glass to determine whether it meets the use requirements;

[0023] S3: Calculate the maximum deflection of the vacuum glass to determine whether it meets the use requirements;

[0024] S4: Determine the tightening torque of the fastening bolts used to install the vacuum glass.

[0025] The vacuum glass window assembly provided by the present invention changes the non-circular window into a circular window, which can meet the vacuum degree lower limit of 10 -5 The sealing of the vacuum chamber of Pa. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following will further explain the above characteristics, technical features, advantages and implementation methods of the present application in a clear and understandable manner through the description of the preferred embodiments and in combination with the accompanying drawings. The following drawings are only intended to illustrate and explain the present application, and do not limit the scope of the present application. Among them:

[0027] Figure 1 is a three-dimensional schematic diagram of a vacuum glass window assembly according to the present application;

[0028] Figure 2 is a side view of a vacuum glass window assembly according to the present application;

[0029] Figure 3 is a top view of a vacuum glass window assembly according to the present application;

[0030] Figure 4 is a side view of a glass mount according to the present application;

[0031] Figure 5 is a side view of a glass gland according to the present application;

[0032] Figure 6a The ANSYS finite element analysis results of the 150mm neck pipe are shown below;

[0033] Figure 6b The ANSYS finite element analysis results of the 150mm neck pipe are shown below;

[0034] Figure 7 is the relationship curve between pressure coefficient f and height coefficient β;

[0035] Figure 8 The relationship between α and β after the sealing ring is compressed;

[0036] Fig. 9 This is the relationship between the hardness and elastic modulus of fluororubber. DETAILED DESCRIPTION

[0037] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific implementation methods of the present application are now described with reference to the accompanying drawings.

[0038] The present invention provides a vacuum glass window assembly for a vacuum container having a non-circular opening thereon, such as Figures 1 to 3 As shown, the vacuum glass window assembly includes:

[0039] The adapter flange 1 has a circular through hole 11 in the middle. The adapter flange 1 is used to be installed on the non-circular opening of the vacuum container. The shape of the adapter flange 1 is designed to match the shape of the non-circular opening of the vacuum container to cover the non-circular opening. In this embodiment, in order to cover the non-circular opening on the vacuum container into a square shape, the adapter flange 1 is designed to be square;

[0040] The round high-neck flange 2 is installed on the adapter flange 1, such as Figure 2 As shown, the high neck flange 2 is provided with a window 21 and a glass mounting seat 22 (such as Figure 2 and Figure 4 As shown), the glass mounting seat 22 has a mounting surface;

[0041] Annular glass gland 4 (such as Figure 2 and Figure 5 As shown), mounted on the glass mounting seat 22 of the high neck flange 2;

[0042] The vacuum glass 3 is installed between the mounting surface of the glass mounting seat 22 of the high-neck flange 2 and the glass gland 4. The high vacuum seal between the vacuum glass 3 and the high-neck flange 2 is achieved by using the O-type vacuum glass sealing ring on the mounting surface. The glass mounting seat 22 and the glass gland 4 are connected by fastening bolts 7, so that the vacuum glass 3 is pressed between the glass mounting seat 22 and the glass gland 4.

[0043] The protection plate 6 is installed on the annular glass pressure cover 4 to cover the vacuum glass 3.

[0044] In this embodiment, the specific connection method of the adapter flange 1 to the vacuum container is as follows: the surface of the adapter flange 1 in contact with the vacuum container is a plane, and the portion of the vacuum container in contact with the adapter flange 1 has a sealing ring groove for accommodating the sealing ring; the adapter flange 1 is pressed and connected to the vacuum container by bolts, and the sealing between the adapter flange 1 and the vacuum container is achieved by the sealing ring between the two.

[0045] The high neck flange 2 can be connected to the adapter flange 1 by argon arc welding. After welding, a helium mass spectrometer leak test is performed to ensure that the vacuum environment is available.

[0046] The high-neck flange 2 is used to connect the non-circular adapter flange 1 and the vacuum glass 3. In order to avoid additional stress on the vacuum glass due to the deformation of the non-circular adapter flange 1, the neck tube length of the high-neck flange 2 is determined according to the minimum deformation of the mounting surface of the glass mounting seat 22. Preferably, the neck tube length of the high-neck flange 2 is 1 / 3 to 2 / 3 of the diameter of its window.

[0047] In one embodiment of the present invention, a DN400 high neck flange is used to connect the adapter flange 1 and the vacuum glass 3. In order to avoid the additional stress on the vacuum glass caused by the deformation of the square flange of the vacuum container, the length of the flange neck tube is determined according to the minimum deformation of the glass seat mounting surface. Through ANSYS finite element analysis of the two lengths of 150mm and 250mm neck tubes, it is found that the maximum deformation of the 150mm neck tube on the glass mounting seat is 2.0899 (as shown in Figure 2). Figure 6a The maximum deformation of the 250mm neck tube on the glass mount is 2.0891 (as shown in Figure 6b As shown), it can be seen that these two neck tube lengths have little effect on the deformation of the vacuum glass mounting flange surface.

[0048] According to one aspect of the present invention, a protective plate 4 is installed outside the vacuum glass 3. To prevent the vacuum glass from being bumped during use, the protective plate is selected to meet the light transmittance requirements.

[0049] The vacuum glass window assembly provided by the present invention changes the non-circular window on the vacuum container into a circular window through the adapter flange and the high neck flange, which can effectively improve the force uniformity of the vacuum glass, so that the safety and transmittance of the vacuum glass can be taken into account, and the vacuum degree lower limit is 10 -5 The sealing of Pa's vacuum chamber meets the requirements for transmittance.

[0050] The present invention also provides a design method for the above vacuum glass window assembly, which further improves the safety of the vacuum glass window assembly by optimizing parameters such as the thickness of the vacuum glass and the tightening torque of the vacuum glass fastening bolts. The design method for the vacuum glass window assembly provided by the present invention includes the following steps:

[0051] S1: Determine the thickness of the vacuum glass according to the allowable stress of the vacuum glass, the center distance of the vacuum glass sealing ring, and the safety factor;

[0052] The thickness of vacuum glass is calculated by formula (1):

[0053]

[0054] D—center distance of vacuum glass sealing ring, mm;

[0055] K—structural characteristic coefficient;

[0056] p—design pressure, MPa;

[0057] [σ]—allowable stress of vacuum glass, MPa;

[0058] C—Additional margin.

[0059] For a circular flat cover vacuum glass installed by fastening bolts, the characteristic coefficient K is calculated by the following formula (2):

[0060]

[0061] P L —Total load of preloaded bolts, N;

[0062] b′—the distance between the center of the vacuum glass sealing ring and the center of the bolt, mm;

[0063] Without considering the additional margin, the calculated thickness of the vacuum glass is obtained. According to the experience of using vacuum glass, the thickness of the glass affects the transmittance of the glass. The thicker the glass, the worse the transmittance, which can easily affect the use. Taking into account the situation that it does not affect the transmittance, the safety factor should be 3 to 10 times.

[0064] S2: Calculate the center stress of the vacuum glass to determine whether it meets the use requirements;

[0065] The center point stress of vacuum glass is calculated by the following formula (3):

[0066]

[0067] q—design pressure, MPa;

[0068] R—vacuum glass radius, mm;

[0069] h—vacuum glass thickness, mm;

[0070] S3: Calculate the maximum deflection of the vacuum glass to determine whether it meets the use requirements;

[0071] The maximum deflection of vacuum glass is calculated by the following formula (4):

[0072]

[0073] E—elastic modulus of vacuum glass, MPa;

[0074] S4: Determine the tightening torque of the fastening bolts used to install the vacuum glass;

[0075] When installing vacuum glass, the fastening bolts need to be tightened. If the tightening force is greater than the force of atmospheric pressure on the glass, the force on the vacuum glass will not be consistent with the design, which may cause the glass to break. Therefore, the design principle of the tightening torque of the fastening bolts should be that when the fastening bolts are tightened, the compression height of the vacuum glass sealing ring is greater than the compression height of the sealing ring after the glass is compressed.

[0076] When the O-shaped vacuum glass sealing ring is compressed to a certain height, the required sealing force F is calculated by the following formula (5):

[0077] F=fdπDE……………………(5)

[0078] d—O-shaped vacuum glass sealing ring cross-section diameter, mm;

[0079] D—Inner diameter of O-shaped vacuum glass sealing ring, mm;

[0080] E—Elastic modulus of O-shaped vacuum glass sealing ring, MPa;

[0081] f—pressure coefficient, which is the relationship curve between pressure coefficient f and height coefficient β (such as Figure 7 shown) can be found.

[0082] The tightening torque of the fastening bolt is calculated by the following formula (6):

[0083] T=K*F 0 *d……………………(6)

[0084] K—tightening torque coefficient, 0.2;

[0085] d—nominal thread diameter, mm.

[0086] The O-shaped vacuum glass sealing ring can freely stretch to both sides after being compressed by atmospheric pressure. The experimental relationship curve of the width coefficient α and the height coefficient β after compression is as follows: Figure 8 shown.

[0087] The pressure σ on the vacuum glass sealing ring after being compressed refers to the force per unit area on the compressed part of the O-shaped vacuum glass sealing ring in contact with the flange (glass). σ can be calculated using the following formula (7):

[0088] σ=1.1(1.02-β)E……………………(7)

[0089] σ—sealing pressure, MPa;

[0090] β—width coefficient;

[0091] E—Elastic modulus of sealing ring, MPa.

[0092] The relationship between the hardness and elasticity model of the sealing ring Fig. 9 shown.

[0093] From the Vacuum Design Manual, we know that the sealing pressure σ, height coefficient β. That is, the height of the sealing ring after compression is:

[0094] H=β·d……………………(8)

[0095] After H is obtained by calculation, after the vacuum glass sealing ring is compressed, the distance between the sealing surface of the vacuum glass 3 and the mounting surface of the high neck flange 2 must be greater than (H-groove depth) to ensure that the mounting surfaces of the vacuum glass 3 and the high neck flange 2 will not interfere with each other and the sealing ring meets the use requirements.

[0096] The following takes the example of converting a square opening into a vacuum glass window assembly with a size of DN400 as an example to describe in detail the design method of the vacuum glass window assembly according to the present invention. The design method of the vacuum glass window assembly provided in this embodiment includes the following steps:

[0097] S1: Determine the thickness of the vacuum glass according to the allowable stress of the vacuum glass, the center distance of the vacuum glass sealing ring, and the safety factor;

[0098] The thickness of vacuum glass is calculated by formula (1):

[0099] D—center distance of vacuum glass sealing ring, 417mm;

[0100] K—structural characteristic coefficient;

[0101] p—design pressure, 0.1MPa;

[0102] [σ]—allowable stress of vacuum glass, 16.7MPa;

[0103] C—Additional margin.

[0104] For the circular flat cover vacuum glass installed by fastening bolts, the characteristic coefficient K is calculated by formula (2), and K = 0.34. Without considering the additional margin, the calculated thickness of DN400 vacuum glass is 18.5mm. According to the experience of using vacuum glass, the safety factor should be more than 2.5 times, and the thickness of DN400 vacuum glass is taken as 50mm.

[0105] S2: Calculate the center stress of the vacuum glass to determine whether it meets the use requirements;

[0106] The center point stress of the vacuum glass is calculated by formula (3). After calculation, the center point stress of the vacuum glass is σ=3.3MPa, which meets the use requirements.

[0107] S3: Calculate the maximum deflection of the vacuum glass to determine whether it meets the use requirements;

[0108] The maximum deflection of vacuum glass is calculated by formula (4), and the elastic modulus E of vacuum glass is 7.25×10 4 MPa. After calculation, the maximum deflection of vacuum glass is f=0.05mm, which meets the use requirements.

[0109] S4: Determine the tightening torque of the fastening bolts used to install the vacuum glass.

[0110] When installing vacuum glass, the fastening bolts need to be tightened. If the tightening force is greater than the force of atmospheric pressure on the glass, the force on the vacuum glass will not be consistent with the design, which may cause the glass to break. Therefore, the design principle of the tightening torque of the fastening bolts should be that when the fastening bolts are tightened, the compression height of the vacuum glass sealing ring is greater than the compression height of the sealing ring after the glass is compressed.

[0111] When the O-shaped vacuum glass sealing ring is compressed to a certain height, the required sealing force F is calculated by formula (5). After calculation, when the sealing ring is compressed to a height of 5.6 mm, the sealing force F = 5697 N. That is, the bolt preload is less than 5697 N, corresponding to the single bolt preload F 0 It is 475N.

[0112] The tightening torque is calculated by formula (6), the tightening torque coefficient K = 0.2, and it is calculated that the tightening torque of each bolt shall not be greater than 1.14 N·m.

[0113] Vacuum glass diameter Glass mounting base glass mounting diameter The distance between the glass and the flange edge is 2mm. At the same time, a rubber flexible support is added between the glass and the glass mounting seat during installation.

[0114] The design of the vacuum glass mount is mainly based on the design of the sealing ring. For the DN400 observation window, an O-ring with a cross-sectional diameter of 7mm and an inner diameter of 410mm is selected. The corresponding sealing groove is 7mm wide and 4.2mm deep.

[0115] The O-shaped vacuum glass sealing ring can freely stretch to both sides after being compressed by atmospheric pressure. The experimental relationship curve of the width coefficient α and the height coefficient β after compression is shown in Figure 6.

[0116] The pressure σ on the vacuum glass sealing ring after being compressed refers to the force per unit area on the compressed part of the O-shaped vacuum glass sealing ring in contact with the flange (glass). σ can be calculated using formula (7). The relationship between the sealing ring hardness and the elastic model is shown in the figure below. Figure 7 As shown, the hardness of fluororubber is 70HS, and the corresponding elastic model is 5.4MPa.

[0117] It can be seen from the "Vacuum Design Manual" that the sealing pressure σ should be 1.3MPa, then the height coefficient β = 0.8.

[0118] After calculation, H = 5.6mm, so after the vacuum glass sealing ring is compressed, the distance between the sealing surface of the vacuum glass 3 and the mounting surface of the high neck flange 2 is 1.4mm (sealing groove depth 4.2mm). There will be no interference between the glass and the flange sealing surface, and the sealing ring meets the use requirements.

[0119] The above description is only an illustrative embodiment of the present application and is not intended to limit the scope of the present application. Any equivalent changes, modifications and combinations made by any technician in the field without departing from the concept and principle of the present application shall fall within the scope of protection of the present application.

Claims

1. A vacuum glass window assembly for a vacuum container having a non-circular opening, the vacuum glass window assembly comprising: An adapter flange has a circular through hole in the middle, and the adapter flange is used to be installed on the non-circular opening of the vacuum container. The shape of the adapter flange is designed to match the shape of the non-circular opening of the vacuum container so as to cover the non-circular opening; A circular high-neck flange is mounted on the adapter flange, the high-neck flange is provided with a window, and has a glass mounting seat surrounding the window, and the glass mounting seat has a mounting surface; The annular glass gland is installed on the glass mounting seat of the high neck flange; The vacuum glass is installed between the mounting surface of the glass mounting seat of the high-neck flange and the glass gland. The high vacuum seal between the vacuum glass and the high-neck flange is achieved by using the O-type vacuum glass sealing ring on the mounting surface. The glass mounting seat and the glass gland are connected by fastening bolts, so that the vacuum glass is pressed between the glass mounting seat and the glass gland. A protective plate is installed on the glass gland to cover the vacuum glass.

2. The assembly according to claim 1, wherein The thickness of vacuum glass is determined according to the allowable stress of vacuum glass, the center distance of vacuum glass sealing ring and the safety factor.

3. The assembly according to claim 1, wherein: The adapter flange is square.

4. The assembly according to claim 1, wherein: The surface where the adapter flange contacts the vacuum container is a plane, and the portion where the vacuum container contacts the adapter flange is provided with a sealing ring groove for accommodating the sealing ring.

5. The assembly according to claim 1, wherein: The adapter flange is compressed and connected to the vacuum container by bolts, and a sealing ring is used to seal the adapter flange and the vacuum container.

6. The assembly according to claim 1, wherein: The high neck flange is connected to the high neck flange by argon arc welding.

7. The assembly according to claim 1, wherein: The neck length of the high neck flange is one third to two thirds of the window diameter of the high neck flange.

8. The assembly of claim 1, wherein: The neck length of the high neck flange is 150mm or 250mm.

9. A vacuum container comprising the vacuum glass window assembly according to claim 1.

10. The method for designing a vacuum glass window assembly according to claim 1, comprising: S1: Determine the thickness of the vacuum glass according to the allowable stress of the vacuum glass, the center distance of the vacuum glass sealing ring, and the safety factor; S2: Calculate the center stress of the vacuum glass to determine whether it meets the use requirements; S3: Calculate the maximum deflection of the vacuum glass to determine whether it meets the use requirements; S4: Determine the tightening torque of the fastening bolts used to install the vacuum glass.

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