Radio frequency shielding type flange structure and installation method thereof

Abstract

The invention discloses a radio frequency shielding type flange structure and an installation method thereof, the radio frequency shielding type flange structure comprises a first flange, the inner side of the sealing surface of the first flange is provided with a plurality of first protruding parts; a plurality of second convex parts are arranged on the inner side of the sealing surface of the second flange; a first step groove is formed in the inner edge of the first sealing face of the sealing ring, a plurality of third protruding parts are arranged in the first step groove, a second step groove is formed in the inner edge of the second sealing face of the sealing ring, and a plurality of fourth protruding parts are arranged in the second step groove; the first protruding parts are inserted into the first step grooves and distributed with the third protruding parts in a staggered mode. The second protruding parts are inserted into the second step grooves and distributed with the fourth protruding parts in a staggered mode. The inner diameter of the first flange, the inner diameter of the second flange and the inner diameter of the sealing ring are equal. Smooth transition between the first flange and the second flange is achieved through the sealing ring and the protruding parts, and impedance at the connecting position of the first flange and the second flange is reduced.

Description

Technical Field

[0001] The present invention relates to the field of flange technology, and in particular to a radio frequency shielding flange structure and an installation method thereof. Background Art

[0002] The charged particle beam in the accelerator will interact electromagnetically with the vacuum chamber it passes through and generate an electromagnetic field called a wake field. When the wake field is generated, it will in turn act on the electron beam, thereby interfering with the movement of the electron beam and making it unstable. This is especially important in situations where the electron beam has a high repetition frequency. During the operation of the accelerator, there are high requirements for the stability of the electron beam, so it is necessary to avoid electromagnetic interaction between the electron beam and the vacuum chamber. Generally, it can be characterized by the beam vacuum impedance. The discontinuous transition of the inner wall of the vacuum chamber and the non-uniform inner diameter will cause the impedance to rise. The greater the impedance, the stronger the wake field generated by the electron beam. Although the impedance generated by a single traditional CF (Conflat Flang) flange is small, due to the large number of ultra-high vacuum flanges in the particle accelerator device (hundreds to thousands), the impedance generated by the flange cannot be ignored and becomes one of the main sources of impedance in the particle accelerator. Therefore, in the process of particle accelerator engineering design, it is very important to use RF (Radio Frequency) shielding structure for flange connection to ensure the quality of particle bunches and maintain the good operation of the accelerator.

[0003] Charged particles in the accelerator must pass through various obstacles during operation, and the obstacles are mainly concentrated in the connection parts between the vacuum equipment itself and different equipment (between vacuum chambers, between vacuum chambers and bellows, between vacuum tubes and other system equipment cavities). Flange connections are now commonly used for connections between different equipment. The CF-type knife-edge sealing flanges commonly used in ultra-high vacuum equipment are prone to produce transverse steps and longitudinal grooves at the connection. These steps and grooves will produce electromagnetic interactions with charged particles. In order to describe this electromagnetic interaction, the concept of impedance is introduced. The higher the impedance, the stronger the electromagnetic interaction. Normally, the impedance of a pair of flange connection transition sections is very small, but due to the large number of flanges on the entire platform, the total impedance of all flanges becomes very large.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a radio frequency shielding flange structure and an installation method thereof in view of the above-mentioned defects of the prior art, aiming to solve the problem of large impedance of the flange structure in the prior art.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] A radio frequency shielding flange structure, comprising:

[0008] A first flange, wherein a plurality of first protrusions are arranged on an inner side of a sealing surface of the first flange;

[0009] A second flange, wherein a plurality of second protrusions are arranged on an inner side of a sealing surface of the second flange;

[0010] A sealing ring, wherein the inner edge of the first sealing surface of the sealing ring is provided with a first step groove, a plurality of third protrusions are provided in the first step groove, and the inner edge of the second sealing surface of the sealing ring is provided with a second step groove, and a plurality of fourth protrusions are provided in the second step groove;

[0011] Wherein, the first protrusion is inserted into the first step groove and is staggered with the third protrusion;

[0012] The second protrusion is inserted into the second step groove and is staggered with the fourth protrusion;

[0013] The inner diameter of the first flange, the inner diameter of the second flange and the inner diameter of the sealing ring are equal.

[0014] The radio frequency shielding flange structure, wherein the height of the first raised portion is less than or equal to 0.5 mm, the radial width of the first raised portion is less than or equal to 0.5 mm, and the central angle corresponding to the first raised portion is less than or equal to 4°;

[0015] The height of the second protrusion is less than or equal to 0.5 mm, the radial width of the second protrusion is less than or equal to 0.5 mm, and the central angle corresponding to the second protrusion is less than or equal to 4°;

[0016] The height of the third protrusion protruding from the first step groove is less than or equal to 0.5 mm, the radial width of the third protrusion is less than or equal to 0.5 mm, and the central angle corresponding to the third protrusion is less than or equal to 4°;

[0017] The height of the fourth protrusion protruding from the second step groove is less than or equal to 0.5 mm, the radial width of the fourth protrusion is less than or equal to 0.5 mm, and the central angle corresponding to the fourth protrusion is less than or equal to 4°;

[0018] The third protrusion protrudes from the first sealing surface;

[0019] The fourth protrusion protrudes from the second sealing surface;

[0020] The height of the first protrusion protruding from the first step groove is less than the height of the third protrusion;

[0021] A height of the second protrusion protruding from the second step groove is smaller than a height of the fourth protrusion.

[0022] The radio frequency shielding flange structure, wherein the outer side of the sealing ring is provided with at least two positioning portions, the positioning portions are located on a side close to the fourth raised portion, and the second flange is provided with at least two positioning grooves;

[0023] The positioning portion is located in the positioning groove, and a radial distance between an outer side surface of the positioning portion and a groove wall of the positioning groove is less than or equal to 0.036 mm.

[0024] The radio frequency shielding flange structure, wherein the first flange comprises:

[0025] A body formed with a groove;

[0026] A loose set, located in the groove;

[0027] Wherein, the first protrusion is arranged on the loose fitting member.

[0028] The radio frequency shielding flange structure, wherein the first flange and the second flange are both CF flanges;

[0029] The sealing surface of the first flange is provided with a first placement groove, and the first protrusion is located in the first placement groove;

[0030] The sealing surface of the second flange is provided with a second placement groove, and the second protrusion is located in the second placement groove;

[0031] Wherein, the sealing ring is located in the first placement groove and the second placement groove.

[0032] The radio frequency shielding flange structure, wherein a first blade is provided in the first placement groove, and the first blade is provided around the first protrusion;

[0033] A second blade is disposed in the second placement groove, and the second blade is disposed around the second raised portion;

[0034] At least one first leak detection groove and a plurality of first locking holes are formed on the first flange, the first leak detection groove is communicated with the first placement groove, and the first locking holes are located outside the first placement groove;

[0035] At least one second leak detection groove and a plurality of second locking holes are formed on the second flange. The second leak detection groove is communicated with the second placement groove, and the second locking holes are located outside the second placement groove.

[0036] The radio frequency shielding flange structure, wherein the first blade has a first vertical wall and a first inclined wall, the first vertical wall faces the first protruding portion, and the first inclined wall faces away from the first protruding portion;

[0037] The second blade has a second vertical wall and a second inclined wall, wherein the second vertical wall faces the second protruding portion, and the second inclined wall faces away from the second protruding portion.

[0038] In the radio frequency shielding flange structure, there is a radial gap between the sealing ring and the first placement groove, and between the sealing ring and the second placement groove.

[0039] A method for installing the radio frequency shielding flange structure as described above, comprising the steps of:

[0040] Assembling the sealing ring and the first flange on the second flange;

[0041] The first flange and the second flange are pre-tightened to complete the installation; wherein the pre-tightening torque of the pre-tightening operation is greater than or equal to 6 N·m.

[0042] The installation method of the radio frequency shielding flange structure, wherein the leakage rate of the radio frequency shielding flange structure is less than or equal to 5×10 -13 Pa·m 3 / s; the axial distance between the end face of the third protrusion and the sealing surface of the first flange is less than or equal to 0.1mm, and the axial distance between the end face of the fourth protrusion and the sealing surface of the second flange is less than or equal to 0.1mm.

[0043] Beneficial effects: There is a gap between the sealing surface of the first flange and the first sealing surface of the sealing ring, and the first protrusion and the third protrusion are filled in the gap; there is a gap between the sealing surface of the second flange and the second sealing surface of the sealing ring, and the second protrusion and the fourth protrusion are filled in the gap. A smooth transition is achieved between the first flange and the second flange through the sealing ring and the protrusions, which reduces the impedance at the connection between the first flange and the second flange. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of the radio frequency shielding flange structure in an embodiment of the present invention.

[0045] Figure 2 It is a cross-sectional view of the radio frequency shielding flange structure in an embodiment of the present invention.

[0046] Figure 3 yes Figure 2 Enlarged view of point A in the middle.

[0047] Figure 4It is an exploded view of the radio frequency shielding flange structure in an embodiment of the present invention.

[0048] Figure 5 It is a schematic structural diagram of the first flange in an embodiment of the present invention.

[0049] Figure 6 Schematic diagram of the structure of the sealing ring in the embodiment of the present invention.

[0050] Figure 7 Schematic diagram of the structure of the second flange in an embodiment of the present invention.

[0051] Figure 8 It is an exploded view of the first flange and the sealing ring in the embodiment of the present invention.

[0052] Fig. 9 It is a schematic diagram of the structure of the test device for ultra-high vacuum debugging in an embodiment of the present invention.

[0053] Description of reference numerals:

[0054] 10. First flange; 11. First protrusion; 12. Main body; 13. Loose set; 14. First placement groove; 15. First knife edge; 151. First vertical wall; 152. First inclined wall; 16. First leak detection groove; 17. First locking hole; 20. Second flange; 21. Second protrusion; 22. Positioning groove; 23. Second placement groove; 24. Second knife edge; 241. Second vertical wall; 242. Second inclined wall; 25. Second leak detection groove; 26. Second locking hole; 30. Sealing ring; 31. First step groove; 32. Third protrusion; 33. Second step groove; 34. Fourth protrusion; 35. Positioning part; 40. Locking accessory. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0056] Please also see Figure 1-Figure 9 The present invention provides some embodiments of a radio frequency shielding flange structure.

[0057] In the structural design process of the shielding flange-sealing ring, the simplicity of the structure and the versatility of the materials are first considered to ensure that no complicated process is added during mass production; it is also necessary to ensure that in actual engineering, a smaller pre-tightening torque can achieve effective ultra-high vacuum sealing, thereby reducing the difficulty of engineering implementation; the most important thing is to ensure that after the shielding flange and the sealing ring are pre-tightened, the transition section can achieve a good smooth transition.

[0058] like Figure 1 , Figure 3 as well as Figure 6 As shown, the radio frequency shielding flange structure of the present invention comprises:

[0059] A first flange 10, wherein a plurality of first protrusions 11 are provided on the inner side of a sealing surface of the first flange 10;

[0060] A second flange 20, wherein a plurality of second protrusions 21 are provided on the inner side of the sealing surface of the second flange 20;

[0061] A sealing ring 30, wherein the inner edge of the first sealing surface of the sealing ring 30 is provided with a first step groove 31, wherein the first step groove 31 is provided with a plurality of third protrusions 32, and the inner edge of the second sealing surface of the sealing ring 30 is provided with a second step groove 33, wherein the second step groove 33 is provided with a plurality of fourth protrusions 34;

[0062] Among them, the first protrusion 11 is inserted into the first step groove 31 and is staggered with the third protrusion 32; the second protrusion 21 is inserted into the second step groove 33 and is staggered with the fourth protrusion 34; the inner diameter of the first flange 10, the inner diameter of the second flange 20 and the inner diameter of the sealing ring 30 are equal.

[0063] Specifically, the first flange 10 and the second flange 20 are sealed by the sealing ring 30. The first flange 10 and the second flange 20 can be connected to the pipe structure to be connected. For example, the first flange 10 is welded to the structure to be connected, and the second flange 20 is welded to another structure to be connected. The connection of the two structures to be connected is achieved through the first flange 10 and the second flange 20, and the sealing ring 30 is sealed. The first flange 10 and the second flange 20 can adopt CF (Conflat Flang) flanges. CF flanges are commonly used for flange connections in ultra-vacuum and ultra-high vacuum, and can withstand high-temperature baking. The first flange 10 and the second flange 20 are usually made of stainless steel, such as 304 stainless steel and 316 stainless steel. The sealing ring 30 is usually made of metal materials, such as oxygen-free copper.

[0064] The first flange 10, the second flange 20 and the sealing ring 30 all have inner holes. The inner holes of the first flange 10, the second flange 20 and the sealing ring 30 are coaxially arranged, and the inner diameters of the inner holes are equal. Usually, the coaxiality error of the inner hole of the first flange 10 and the inner hole of the second flange 20 is small. The coaxiality error between the inner hole of the sealing ring 30 and the inner hole of the first flange 10 is less than or equal to 0.036mm, and the coaxiality error between the inner hole of the sealing ring 30 and the inner hole of the second flange 20 is less than or equal to 0.036mm. The error of the inner hole diameter of the flange is less than or equal to 0.02mm, and the error of the inner hole diameter of the sealing ring 30 is less than or equal to 0.02mm. The inner hole diameter of the sealing ring 30 can also be slightly increased to compensate for the deformation of the sealing ring after being pressed. For example, the inner hole diameter of the sealing ring 30 is D+0.02mm, and D represents the theoretical inner hole diameter of the sealing ring 30. There is a gap between the sealing surface of the first flange 10 and the first sealing surface of the sealing ring 30, and the first protrusion 11 and the third protrusion 32 are filled in the gap; there is a gap between the sealing surface of the second flange 20 and the second sealing surface of the sealing ring 30, and the second protrusion 21 and the fourth protrusion 34 are filled in the gap, and the protrusions cross each other to form an interdigitated structure. The first flange 10 and the second flange 20 achieve a smooth transition through the sealing ring 30 and the protrusions, reducing the impedance of the connection between the first flange 10 and the second flange 20.

[0065] The sealing surface of the first flange 10 is perpendicular to the inner hole of the first flange 10 (no chamfer is set), and the sealing surface of the second flange 20 is perpendicular to the inner hole of the second flange 20 (no chamfer is set). When the inner hole of the sealing ring 30 is connected with the inner hole of the first flange 10 and the inner hole of the second flange 20, the inner surface of the inner hole forms a smooth hole wall to reduce the beam vacuum impedance caused by the change of the inner diameter of the connecting transition section. At the same time, it also has the advantages of low cost, simple structure and easy sealing.

[0066] The protrusion (including the first protrusion 11, the second protrusion 21, the third protrusion 32 and the fourth protrusion 34) has an end face, two circumferential side faces and two radial side faces. The axial direction refers to the axial direction of the flange (including: the first flange 10 and the second flange 20), and the radial direction refers to the radial direction of the flange. The radial side face is an arc-shaped side face, which matches the arc shape of the inner hole. The circumferential side face of the first protrusion 11 and the circumferential side face of the third protrusion 32 are close to or fit each other, and the circumferential side face of the second protrusion 21 and the circumferential side face of the fourth protrusion 34 are close to or fit each other. In order to facilitate the insertion of each protrusion, there is a certain circumferential gap between the first protrusion 11 and the third protrusion 32, and there is a certain circumferential gap between the second protrusion 21 and the fourth protrusion 34. Of course, the smaller the circumferential gap, the smaller the impedance. The number of the protrusions is determined as needed. For example, the number of the first protrusion 11 , the second protrusion 21 , the third protrusion 32 and the fourth protrusion 34 are all 36.

[0067] The sealing surface of the first flange 10 is the side of the first flange 10 facing the second flange 20, the sealing surface of the second flange 20 is the side of the second flange 20 facing the first flange 10, and the two sides of the sealing ring 30 are the first sealing surface and the second sealing surface respectively. In order to achieve the sealing between the first flange 10 and the sealing ring 30, and the sealing between the second flange 20 and the sealing ring 30, the first flange 10 and the second flange 20 will be pressed. The end face of the first protrusion 11 abuts against the first step groove 31, and the end face of the second protrusion 21 abuts against the second step groove 33; the end face of the third protrusion is close to or abuts against the sealing surface of the first flange 10, and the end face of the fourth protrusion 34 is close to or abuts against the sealing surface of the second flange 20, then the axial clearance between the sealing ring 30 and the first flange 10 and the second flange 20 is small.

[0068] In a preferred implementation of the embodiment of the present invention, Figure 7 As shown, the height of the first protrusion 11 is less than or equal to 0.5 mm, the radial width of the first protrusion 11 is less than or equal to 0.5 mm, and the central angle corresponding to the first protrusion 11 is less than or equal to 4°.

[0069] Specifically, the height of the first protrusion 11 refers to the height of the first protrusion 11 protruding from the sealing surface of the first flange 10, the radial width of the first protrusion 11 refers to the distance between the two radial side surfaces of the first protrusion 11, and the central angle corresponding to the first protrusion 11 refers to the central angle corresponding to the first protrusion 11 with the center of the inner hole of the flange as the center of the circle. The height and radial width of the first protrusion 11 are not greater than 0.5 mm, and the central angle corresponding to the first protrusion 11 is not greater than 4°, for example, the central angle corresponding to the first protrusion 11 is 3.6°.

[0070] In a preferred implementation of the embodiment of the present invention, Figure 5 As shown, the height of the second protrusion 21 is less than or equal to 0.5 mm, the radial width of the second protrusion 21 is less than or equal to 0.5 mm, and the central angle corresponding to the second protrusion 21 is less than or equal to 4°.

[0071] Specifically, the height of the second protrusion 21 refers to the height of the second protrusion 21 protruding from the sealing surface of the second flange 20, the radial width of the second protrusion 21 refers to the distance between the two radial side surfaces of the second protrusion 21, and the central angle corresponding to the second protrusion 21 refers to the central angle corresponding to the second protrusion 21 with the center of the inner hole of the flange as the center of the circle. The height and radial width of the second protrusion 21 are not greater than 0.5 mm, and the central angle corresponding to the second protrusion 21 is not greater than 4°, for example, the central angle corresponding to the second protrusion 21 is 3.6°.

[0072] In a preferred implementation of the embodiment of the present invention, Figure 6 As shown, the height of the third protrusion 32 protruding from the first step groove 31 is less than or equal to 0.5 mm, the radial width of the third protrusion 32 is less than or equal to 0.5 mm, and the central angle corresponding to the third protrusion 32 is less than or equal to 4°.

[0073] Specifically, the radial width of the third protrusion 32 refers to the distance between the two radial side surfaces of the third protrusion 32, and the central angle corresponding to the third protrusion 32 refers to the central angle corresponding to the third protrusion 32 with the center of the inner hole of the flange as the center. The height and radial width of the third protrusion 32 are not greater than 0.5 mm, and the central angle corresponding to the third protrusion 32 is not greater than 4°, for example, the central angle corresponding to the third protrusion 32 is 3.6°.

[0074] In a preferred implementation of the embodiment of the present invention, Figure 6 As shown, the height of the fourth protrusion 34 protruding from the second step groove 33 is less than or equal to 0.5 mm, the radial width of the fourth protrusion 34 is less than or equal to 0.5 mm, and the central angle corresponding to the fourth protrusion 34 is less than or equal to 4°.

[0075] Specifically, the radial width of the fourth protrusion 34 refers to the distance between the two radial side surfaces of the fourth protrusion 34, and the central angle corresponding to the fourth protrusion 34 refers to the central angle corresponding to the fourth protrusion 34 with the center of the inner hole of the flange as the center. The height and radial width of the fourth protrusion 34 are not greater than 0.5 mm, and the central angle corresponding to the fourth protrusion 34 is not greater than 4°, for example, the central angle corresponding to the fourth protrusion 34 is 3.6°.

[0076] In a preferred implementation of the embodiment of the present invention, Figure 3 and Figure 6 As shown, the third protrusion 32 protrudes from the first sealing surface; and the fourth protrusion 34 protrudes from the second sealing surface.

[0077] Specifically, the third protrusion 32 protrudes from the first sealing surface, and the fourth protrusion 34 protrudes from the second sealing surface. Compared with the first sealing surface, the third protrusion 32 is easier to abut against the sealing surface of the first flange 10. Compared with the second sealing surface, the fourth protrusion 34 is easier to abut against the sealing surface of the second flange 20.

[0078] In a preferred implementation of the embodiment of the present invention, Figure 6 As shown, the groove depth of the first step groove 31 is less than or equal to 0.4 mm; the groove depth of the second step groove 33 is less than or equal to 0.4 mm.

[0079] Specifically, the groove depth of the first step groove 31 is not greater than 0.4 mm, and the groove depth of the second step groove 33 is not greater than 0.4 mm.

[0080] In a preferred implementation of the embodiment of the present invention, Figure 3 As shown, the height of the first protrusion 11 protruding from the first step groove 31 is smaller than the height of the third protrusion 32 .

[0081] Specifically, the height of the first protrusion 11 protruding from the first step groove 31 is less than the height of the third protrusion 32 , so the first protrusion 11 is more likely to abut against the first step groove 31 , and the third protrusion 32 is slightly more difficult to abut against the sealing surface of the first flange 10 .

[0082] In a preferred implementation of the embodiment of the present invention, Figure 3 As shown, the height of the second protrusion 21 protruding from the second step groove 33 is less than the height of the fourth protrusion 34 .

[0083] Specifically, the height of the second protrusion 21 protruding from the second step groove 33 is less than that of the fourth protrusion 34 , so the second protrusion 21 is more likely to abut against the second step groove 33 , while the fourth protrusion 34 is slightly less likely to abut against the sealing surface of the second flange 20 .

[0084] In a preferred implementation of the embodiment of the present invention, Figure 2 , Figure 3 as well as Figure 7 As shown, the sealing surface of the first flange 10 is provided with a first placement groove 14, and the first protrusion 11 is located in the first placement groove 14; the sealing surface of the second flange 20 is provided with a second placement groove 23, and the second protrusion 21 is located in the second placement groove 23; wherein, the sealing ring 30 is located in the first placement groove 14 and the second placement groove 23.

[0085] Specifically, the first flange 10 and the second flange 20 can adopt CF flanges, and a first placement groove 14 is provided on the sealing surface of the first flange 10, the inner hole of the first flange 10 is located at the bottom of the first placement groove 14, and the first protrusion 11 is located in the first placement groove 14 and is arranged around the inner hole of the first flange 10. A second placement groove 23 is provided on the sealing surface of the second flange 20, the inner hole of the second flange 20 is located at the bottom of the second placement groove 23, and the second protrusion 21 is located in the second placement groove 23 and is arranged around the inner hole of the second flange 20. The first placement groove 14 and the second placement groove 23 are used to place the sealing ring 30, and a part of the sealing ring 30 is located in the first placement groove 14, and the other part is located in the second placement groove 23.

[0086] In a preferred implementation of the embodiment of the present invention, Figure 3 and Figure 7 As shown, a first cutting edge 15 is arranged in the first placement groove 14, and the first cutting edge 15 is arranged around the first protrusion 11; at least one first leak detection groove 16 and a plurality of first locking holes 17 are formed on the first flange 10, the first leak detection groove 16 is connected to the first placement groove 14, and the first locking holes 17 are located outside the first placement groove 14.

[0087] Specifically, the first blade 15 in the first placement groove 14 is an annular blade and is arranged around the first protrusion. When the first flange 10 and the second flange 20 are pressed against each other, the first blade 15 is inserted into the first sealing surface of the sealing ring 30, thereby isolating the inside and outside of the first blade 15. The first leak detection groove 16 is connected to the first placement groove 14, and the air outside the first blade 15 circulates with the outside air through the first leak detection groove 16. The first locking hole 17 is for the locking accessory 40 to pass through, so as to realize the mutual pressing of the first flange 10 and the second flange 20.

[0088] In a preferred implementation of the embodiment of the present invention, Figure 3 and Figure 5 As shown, a second cutting edge 24 is arranged in the second placement groove 23, and the second cutting edge 24 is arranged around the second protrusion 21; at least one second leak detection groove 25 and a plurality of second locking holes 26 are formed on the second flange 20, the second leak detection groove 25 is connected to the second placement groove 23, and the second locking holes 26 are located outside the second placement groove 23.

[0089] Specifically, the second blade 24 in the second placement groove 23 is an annular blade and is arranged around the second protrusion. When the first flange 10 and the second flange 20 are pressed against each other, the second blade 24 is inserted into the second sealing surface of the sealing ring 30, thereby isolating the inner and outer sides of the second blade 24. The second leak detection groove 25 is connected to the second placement groove 23, and the air outside the second blade 24 circulates with the outside air through the second leak detection groove 25. The first blade 15, the first protrusion 11, the third protrusion 32, the first flange 10 and the sealing ring 30 form a relatively closed space around, and the second blade 24, the second protrusion 21, the fourth protrusion 34, the second flange 20 and the sealing ring 30 form a relatively closed space around. The relatively closed space is generally referred to as a "dead space", and a small amount of gas remaining inside is extracted when vacuuming. The second locking hole 26 is for the locking accessory 40 to pass through, so as to realize the mutual pressing of the first flange 10 and the second flange 20.

[0090] The locking attachment 40 can be a bolt and a nut. After the bolt passes through the first locking hole 17 and the second locking hole 26, the bolt and the nut are connected. When the nut is tightened, the first flange 10 and the second flange 20 are pressed against each other, and the first blade 15 and the second blade 24 are inserted into the sealing ring 30 to achieve a sealed connection between the first flange 10 and the second flange 20. The first leak detection groove 16 and the second leak detection groove 25 are both rectangular cross-section grooves with a width of 1.5 mm and a depth of 1.94 mm. The positions of the first leak detection groove 16 and the second leak detection groove 25 correspond to each other.

[0091] In a preferred implementation of the embodiment of the present invention, Figure 3 and Figure 7 As shown, the first blade 15 has a first vertical wall 151 and a first inclined wall 152 , wherein the first vertical wall 151 faces the first protruding portion 11 , and the first inclined wall 152 faces away from the first protruding portion 11 .

[0092] In a preferred implementation of the embodiment of the present invention, Figure 3 and Figure 5 As shown, the second blade 24 has a second vertical wall 241 and a second inclined wall 242 , wherein the second vertical wall 241 faces the second protruding portion 21 , and the second inclined wall 242 faces away from the second protruding portion 21 .

[0093] Specifically, the two sides of the knife edge are a vertical wall and an inclined wall. The vertical wall refers to the side that is upright relative to the sealing surface of the flange (the vertical wall is specifically a cylindrical side), and the angle between the vertical wall and the sealing surface of the flange is close to 90°. The inclined wall refers to the side that is inclined relative to the sealing surface of the flange (the inclined wall is specifically a conical table side), and the angle between the inclined wall and the sealing surface of the flange is about 20° to 50°. The vertical wall is the inner side of the knife edge, and the inclined wall is the outer side of the knife edge. Based on the knife edge, the sealing ring 30 is divided into an inner ring and an outer ring, with the vertical wall facing the inner ring and the inclined wall facing the outer ring. When the knife edge is inserted into the sealing surface of the sealing ring 30, the inclined wall is mainly extruded, and the outer ring undergoes a large extrusion deformation and expands outward, while the vertical wall is mainly cut in, and the inner ring undergoes a small deformation.

[0094] The positions of the first blade 15 and the second blade 24 correspond to each other, the vertical wall of the first blade 15 and the vertical wall of the second blade 24 are both facing the inner ring of the sealing ring 30, and the inclined wall of the first blade 15 and the inclined wall of the second blade 24 are both facing the outer ring of the sealing ring 30. When the first blade 15 and the second blade 24 are inserted into the sealing ring 30, the inner ring of the sealing ring 30 basically does not move, which is conducive to maintaining the inner diameter of the sealing ring 30 unchanged and maintaining good coaxiality with the inner hole of the flange.

[0095] In a preferred implementation of the embodiment of the present invention, Figure 2 and Figure 3As shown, there are radial gaps between the sealing ring 30 and the first placement groove 14 , and between the sealing ring 30 and the second placement groove 23 .

[0096] Specifically, there is a radial gap between the sealing ring 30 and the first placement groove 14, and there is a radial gap between the sealing ring 30 and the second placement groove 23. Since the outer ring of the sealing ring 30 expands outward when the first blade 15 and the second blade 24 are inserted into the sealing ring 30, the radial gap provides a reserved space for the outward expansion of the outer ring of the sealing ring 30, thereby not affecting the shape of the inner ring of the sealing ring 30.

[0097] In a preferred implementation of the embodiment of the present invention, Figure 4 , Figure 6 as well as Figure 8 As shown, at least two positioning portions 35 are provided on the outer side of the sealing ring 30 , and the positioning portion 35 is located on a side close to the fourth protrusion 34 . At least two positioning grooves 22 are provided on the second flange 20 ; and the positioning portion 35 is located in the positioning groove 22 .

[0098] Specifically, the outer side of the sealing ring 30 refers to the radial outer side of the sealing ring 30, and the positioning portion 35 extends radially along the sealing ring 30. The positioning portion 35 is located in the positioning groove 22, and the positioning groove 22 limits the sealing ring 30 in the axial direction, radial direction, and the direction of movement toward the second flange 20, so that the sealing ring 30 can be taken out from the direction away from the second flange 20. In particular, the positioning groove 22 limits the sealing ring 30 in the radial direction, which is conducive to maintaining the coaxiality between the sealing ring 30 and the flange. The positioning groove 22 is connected to the second leak detection groove 25, and the second leak detection groove 25 is connected to the second placement groove 23 through the positioning groove 22.

[0099] In a preferred implementation of the embodiment of the present invention, Figure 3 As shown, the radial distance between the outer side surface of the positioning portion 35 and the groove wall of the positioning groove 22 is less than or equal to 0.036 mm.

[0100] Specifically, the radial spacing between the outer side of the sealing ring 30 and the groove wall of the positioning groove 22 is not greater than 0.036mm, so the sealing ring 30 and the flange have a high coaxiality, and the sealing ring 30 will not deviate to form an axial step between the first flange 10 and the second flange 20, and the cooperation of each protrusion also avoids the radial step. The thickness of the positioning portion 35 is relatively thin and is completely located in the positioning groove 22. Even if the outer ring of the sealing ring 30 expands outward, the positioning portion 35 is squeezed against the groove wall of the positioning groove 22, and the positioning portion 35 is deformed. The depth of the positioning groove 22 does not exceed 1.94mm, the positioning groove 22 can be fan-shaped, and the radial processing tolerance of the positioning groove 22 is not greater than 0.011mm.

[0101] In a preferred implementation of the embodiment of the present invention, Figure 2 and Figure 3 As shown, the first flange 10 comprises:

[0102] The body 12 is formed with a groove;

[0103] A loose set 13, located in the groove;

[0104] Wherein, the first protrusions 11 are all arranged on the loose sleeve 13 .

[0105] Specifically, in order to facilitate the assembly of the first flange 10 and the second flange 20, the first flange 10 adopts a loose flange, and the loose sleeve 13 and the body 12 can be separated from each other to achieve disassembly. The loose sleeve 13 includes: a loose shoulder ring or a loose blind plate, etc. An inner hole is formed on the loose sleeve 13 and the body 12, and the inner hole of the loose sleeve 13 and the inner hole of the body 12 form the inner hole of the first flange 10. The first protrusion 11 and the first blade 15 are both arranged on the loose sleeve 13. The first placement groove 14 can be a part of the groove, and the groove depth of the groove is large. After the loose sleeve 13 is placed, the groove is not completely filled. The unfilled part of the loose sleeve 13 in the groove serves as the first placement groove 14 to place the sealing ring 30.

[0106] The radio frequency shielding flange structure of the present application has the following effects:

[0107] 1. The RF shielding flange structure places a sealing ring on the second flange in sequence, and the loose set and the first flange are fastened by locking accessories to achieve ultra-high vacuum sealing connection of the front and rear devices. It has the advantages of shielding transition, low processing difficulty, simplified shielding structure, and low mass production cost.

[0108] 2. The RF shielding flange structure can easily achieve ultra-high vacuum sealing, effectively reducing the difficulty of engineering installation, effectively reducing the axial gap and radial step of the transition section after the flange and the sealing ring are compressed, and realizing a smooth transition of the connecting transition section. It can effectively improve the stability of the charged particle beam in the accelerator and thus increase the life of the electron beam.

[0109] 3. The RF shielding flange structure is suitable for the connection of any two knife-edge flange devices, and can be connected to different types of upstream and downstream equipment, greatly improving universal applicability.

[0110] Based on the radio frequency shielding flange structure described in any of the above embodiments, the present invention also provides a preferred embodiment of a method for installing a radio frequency shielding flange structure:

[0111] The installation method of the radio frequency shielding flange structure according to the embodiment of the present invention comprises the following steps:

[0112] Step S100, assembling the sealing ring and the first flange on the second flange;

[0113] Step S200: pre-tighten the first flange and the second flange to complete the installation; wherein the pre-tightening torque of the pre-tightening operation is greater than or equal to 6 N·m.

[0114] Specifically, when installing the RF shielding flange structure, first install a sealing ring (such as Figure 8 As shown in the figure), then assemble the first flange. Then pre-tighten the first flange and the second flange to complete the installation of the RF shielding flange structure. The pre-tightening torque of the pre-tightening operation is greater than or equal to 6N·m. Under a smaller pre-tightening torque, the sealing performance can also be greatly improved.

[0115] Step S100 specifically includes:

[0116] Step S110, align the fourth protrusion of the sealing ring with the position between two adjacent second protrusions of the second flange, align the positioning portion with the positioning groove, and place the sealing ring into the second placement groove;

[0117] Step S120, align the first protrusion of the loose sleeve with the position between two adjacent third protrusions of the sealing ring, and cover the loose sleeve and the body.

[0118] Specifically, when installing the sealing ring, the fourth protrusion and the second protrusion need to be inserted alternately so that the second protrusion is inserted into the second step groove, and the positioning portion is inserted into the positioning groove. Then, when installing the first flange, the first protrusion and the third protrusion are inserted alternately so that the first protrusion is inserted into the first step groove. The loose sleeve and the body can be covered successively or together.

[0119] Step S200 specifically includes:

[0120] Step S210: assemble the locking accessories to the first locking holes and the second locking holes, and pre-tighten the first flange and the second flange based on the locking accessories to complete the installation.

[0121] Specifically, align the first locking hole of the body with the second locking hole of the second flange, then insert the bolts into the first locking hole and the second locking hole in sequence, and install the nuts. Twist the nuts with the pre-tightening torque to complete the pre-tightening operation of the first flange and the second flange.

[0122] In order to achieve the best sealing and shielding effect during flange installation, it is required to achieve a smooth transition between the first flange, the sealing ring and the second flange, and ensure that the cross-sectional steps and gaps through which the beam passes are as small as possible. To achieve this goal, first, the inner surface roughness of the flange and the sealing ring meets the requirements, which is met by precision machining; second, the concentricity between the three is ensured during the installation process. In practice, the machining tolerance of the outer cylindrical surface of the first flange and the second flange can be controlled - the roundness and the coaxiality with the inner hole. During the installation process, an auxiliary installation fixture is used externally to ensure that the outer circles of the two flanges are coaxial, thereby achieving the coaxiality of the inner holes of the two flanges to meet the requirements.

[0123] The radio frequency shielding flange structure of the present application can easily achieve ultra-high vacuum sealing, the pre-tightening torque is greater than or equal to 6N·m, and the leakage rate of the radio frequency shielding flange structure is less than or equal to 5×10 -13 Pa·m 3 / s.

[0124] like Fig. 9 As shown in the figure, after the accelerator platform is installed, ultra-high vacuum debugging is required. During the debugging process, high-temperature baking and degassing at no less than 180°C (specifically, baking is performed in a baking machine). When the preload torque is ≥6N·m, after baking and cooling, the results show that the RF shielding flange structure can still meet the ultra-high vacuum sealing requirements, that is, the leakage rate is ≤5×10 -13 Pa·m 3 / s (specifically using a leak detector for detection).

[0125] The axial distance between the end surface of the third protrusion and the sealing surface of the first flange is less than or equal to 0.1 mm, and the axial distance between the end surface of the fourth protrusion and the sealing surface of the second flange is less than or equal to 0.1 mm.

[0126] The factors that affect the size of the axial clearance of the connection transition section between the flange and the sealing ring are the height of the third protrusion of the inner diameter edge of the sealing ring relative to the first step groove and the height of the fourth protrusion relative to the second step groove. The test preload torque is ≥6Nm. The sealing rings whose heights of the third protrusion relative to the first step groove and the fourth protrusion relative to the second step groove are both less than 0.5mm are selected for at least 5 compression tests. The axial clearance between the end face of the third protrusion and the sealing surface of the first flange, and the circumferential clearance between the end face of the fourth protrusion and the sealing surface of the second flange are measured with a feeler gauge. The axial clearance does not exceed 0.1mm.

[0127] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A radio frequency shielding flange structure, characterized in that: include: A first flange, wherein a plurality of first protrusions are arranged on an inner side of a sealing surface of the first flange; A second flange, wherein a plurality of second protrusions are arranged on an inner side of a sealing surface of the second flange; A sealing ring, wherein the inner edge of the first sealing surface of the sealing ring is provided with a first step groove, a plurality of third protrusions are provided in the first step groove, and the inner edge of the second sealing surface of the sealing ring is provided with a second step groove, and a plurality of fourth protrusions are provided in the second step groove; Wherein, the first protrusion is inserted into the first step groove and is staggered with the third protrusion; The second protrusion is inserted into the second step groove and is staggered with the fourth protrusion; The inner diameter of the first flange, the inner diameter of the second flange and the inner diameter of the sealing ring are equal.

2. The radio frequency shielding flange structure according to claim 1, characterized in that: The height of the first protrusion is less than or equal to 0.5 mm, the radial width of the first protrusion is less than or equal to 0.5 mm, and the central angle corresponding to the first protrusion is less than or equal to 4°; The height of the second protrusion is less than or equal to 0.5 mm, the radial width of the second protrusion is less than or equal to 0.5 mm, and the central angle corresponding to the second protrusion is less than or equal to 4°; The height of the third protrusion protruding from the first step groove is less than or equal to 0.5 mm, the radial width of the third protrusion is less than or equal to 0.5 mm, and the central angle corresponding to the third protrusion is less than or equal to 4°; The height of the fourth protrusion protruding from the second step groove is less than or equal to 0.5 mm, the radial width of the fourth protrusion is less than or equal to 0.5 mm, and the central angle corresponding to the fourth protrusion is less than or equal to 4°; The third protrusion protrudes from the first sealing surface; The fourth protrusion protrudes from the second sealing surface; The height of the first protrusion protruding from the first step groove is less than the height of the third protrusion; A height of the second protrusion protruding from the second step groove is smaller than a height of the fourth protrusion.

3. The radio frequency shielding flange structure according to claim 1, characterized in that: The outer side surface of the sealing ring is provided with at least two positioning parts, the positioning parts are located on a side close to the fourth protruding part, and the second flange is provided with at least two positioning grooves; The positioning portion is located in the positioning groove, and a radial distance between an outer side surface of the positioning portion and a groove wall of the positioning groove is less than or equal to 0.036 mm.

4. The radio frequency shielding flange structure according to claim 3, characterized in that: The first flange comprises: A body formed with a groove; A loose set, located in the groove; Wherein, the first protrusion is arranged on the loose fitting member.

5. The radio frequency shielding flange structure according to any one of claims 1 to 4, characterized in that: The first flange and the second flange are both CF flanges; The sealing surface of the first flange is provided with a first placement groove, and the first protrusion is located in the first placement groove; The sealing surface of the second flange is provided with a second placement groove, and the second protrusion is located in the second placement groove; Wherein, the sealing ring is located in the first placement groove and the second placement groove.

6. The radio frequency shielding flange structure according to claim 5, characterized in that: A first blade is disposed in the first placement groove, and the first blade is disposed around the first protrusion; A second blade is disposed in the second placement groove, and the second blade is disposed around the second raised portion; At least one first leak detection groove and a plurality of first locking holes are formed on the first flange, the first leak detection groove is communicated with the first placement groove, and the first locking holes are located outside the first placement groove; At least one second leak detection groove and a plurality of second locking holes are formed on the second flange. The second leak detection groove is communicated with the second placement groove, and the second locking holes are located outside the second placement groove.

7. The radio frequency shielding flange structure according to claim 6, characterized in that: The first blade has a first vertical wall and a first inclined wall, the first vertical wall faces the first protruding portion, and the first inclined wall faces away from the first protruding portion; The second blade has a second vertical wall and a second inclined wall, wherein the second vertical wall faces the second protruding portion, and the second inclined wall faces away from the second protruding portion.

8. The radio frequency shielding flange structure according to claim 7, characterized in that: There are radial gaps between the sealing ring and the first placement groove, and between the sealing ring and the second placement groove.

9. A method for installing a radio frequency shielding flange structure according to any one of claims 1 to 8, characterized in that: Includes steps: Assembling the sealing ring and the first flange on the second flange; The first flange and the second flange are pre-tightened to complete the installation; wherein the pre-tightening torque of the pre-tightening operation is greater than or equal to 6 N·m.

10. The method for installing the radio frequency shielding flange structure according to claim 9, characterized in that: The leakage rate of the radio frequency shielding flange structure is less than or equal to 5×10 -13 Pa·m 3 / s; the axial distance between the end face of the third protrusion and the sealing surface of the first flange is less than or equal to 0.1mm, and the axial distance between the end face of the fourth protrusion and the sealing surface of the second flange is less than or equal to 0.1mm.

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