Ultrahigh vacuum sealing structure and sealing method

Abstract

The invention discloses an ultrahigh vacuum sealing structure and a sealing method. The ultrahigh vacuum sealing structure comprises two butted shells and a metal sealing piece, each shell comprises a butt joint surface and a through hole, and a gap is formed between the butt joint surfaces of the two shells; the metal sealing piece is arranged in the gap and comprises two opposite side faces and a communicating hole penetrating from one side face to the other side face, and the two side faces face the two butt joint faces respectively. More than two sealing rings surrounding the communicating hole are arranged on the side surface in a protruding manner, and one of any two sealing rings falls into the other sealing ring; the distances between at least two sealing rings on each side face and the butt joint face opposite to the side face are not equal, and at least one sealing ring on the side face is matched with the butt joint face opposite to the side face in a pressing mode. The sealing structure formed by at least one sealing ring can meet the ultrahigh vacuum sealing requirement, so that the whole system is simple and convenient to install and easy to machine.

Description

Technical Field

[0001] The present invention relates to the field of vacuum sealing technology, and in particular to an ultra-high vacuum sealing structure and a sealing method. Background Art

[0002] Generally speaking, vacuum is usually divided into four levels, namely, rough vacuum (105-102Pa), low vacuum (102-10-1Pa), high vacuum (10-1-10-6Pa), and ultra-high vacuum (<10-6Pa). Under ultra-high vacuum conditions, the number of gas molecules per cubic centimeter is required to be less than 100, and the leakage needs to be less than 1.0e-11 Pascal cubic meter. Therefore, higher requirements are put forward for sealing, and the commonly used sealing structure is difficult to be applied to ultra-high vacuum environment. At present, the sealing method for ultra-high vacuum is usually achieved by using metal seals. For example, in the commonly used knife-edge sealing structure, a sharp knife-shaped sealing part is set on the hard metal surface, and the sharp knife-shaped sealing part is pressed onto the soft metal surface during sealing to achieve sealing. When the above-mentioned metal sealing structure is used for sealing, when there are tiny defects, the leakage rate at the sealing point does not meet the requirements, and its tiny leakage rate is extremely difficult to be detected, which easily leads to the failure risk of the ultra-high vacuum system in this sealing system. Summary of the invention

[0003] In view of the deficiencies in the prior art, the first object of the present invention is to propose an ultra-high vacuum sealing structure, which is easy to install, has a simple structure, and can meet the sealing requirements of ultra-high vacuum.

[0004] The second purpose of the present invention is to provide a sealing method.

[0005] To achieve the above-mentioned purpose 1, the present invention adopts the following technical solution:

[0006] An ultra-high vacuum sealing structure, comprising two butted shells and a metal seal;

[0007] The shell includes a butt joint surface and a through hole arranged on the butt joint surface and communicating with the inner cavity of the shell. The butt joint surfaces of the two shells are arranged opposite to each other and a gap is formed therebetween.

[0008] The metal seal is placed in the gap, and includes two opposite side surfaces and a connecting hole extending from one of the side surfaces to the other side surface, and the two side surfaces face two butt joint surfaces respectively; two or more sealing rings are protruding from the side surfaces and arranged around the connecting holes, and one of any two sealing rings falls into the inside of the other sealing ring; at least two sealing rings on each side surface are at unequal distances from the butt joint surface opposite to the side surface, and at least one sealing ring on the side surface is pressed and fitted with the butt joint surface opposite to the side surface.

[0009] Preferably, the butt joint surface and the side surface are both planes, and in any two adjacent sealing rings, the height of the outer sealing ring is greater than the height of the inner sealing ring.

[0010] Preferably, more than three sealing rings are provided on the side surface, and the height of the sealing rings gradually increases from the inside to the outside.

[0011] Preferably, the height difference between any two adjacent sealing rings is h, where h≥0.2 mm.

[0012] Preferably, the sealing ring is circular, elliptical or polygonal.

[0013] Preferably, the width of the cross section of the sealing ring gradually decreases from the side connected to the side toward the side close to the butt joint surface.

[0014] Preferably, the width of the sealing ring at a side close to the butt joint surface is 0 to 1.6 mm.

[0015] Preferably, the metal seal is made of oxygen-free copper, aluminum, indium or silver.

[0016] Preferably, the two shells are fixed by bolt connection.

[0017] To achieve the above-mentioned second objective, the present invention adopts the following technical solution:

[0018] The sealing method uses the above-mentioned ultra-high vacuum sealing structure to perform sealing, comprising the following steps performed in sequence:

[0019] S1. Place the metal seal in the gap formed between the butt surfaces of the two shells so that the connecting holes on the metal seal face the through holes on the two shells;

[0020] S2, bring the two shells closer together to gradually reduce the width of the gap, so that the sealing rings on the two side surfaces closest to the two butt joint surfaces are in contact with the two butt joint surfaces respectively;

[0021] S3, continue to move the two shells closer together, so that the sealing ring in contact with the butt joint surface in step S2 is deformed, and when the next sealing ring is about to approach the butt joint surface, stop moving the two shells, and the inner cavities of the two shells are connected to form a sealed cavity through the connecting hole;

[0022] S4, evacuate the sealing chamber and check the leakage rate; if the leakage rate meets the requirement, complete the sealing; if the leakage rate does not meet the requirement, proceed to the following step S5;

[0023] S5, continue to bring the two shells closer together to clamp the metal seal, so that the next sealing ring in step S3 contacts the butt joint surface and deforms.

[0024] The beneficial effects of the present invention are:

[0025] The present invention arranges more than two sealing rings on the side surface directly facing the metal seal and the shell, so that when the mating surface of the shell approaches the metal seal, the sealing rings can successively contact the mating surface and deform, and the sealing structure formed by at least one sealing ring meets the ultra-high vacuum sealing requirement; during assembly, it is only necessary to make the shell close to the metal seal in one direction, so that the installation of the entire system becomes simple and convenient; in addition, the multiple sealing rings on the metal seal can be formed at one time by machining, so that the metal seal is easy to process and form. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0027] Figure 2 for Figure 1 Schematic diagram of the structure of the metal seal;

[0028] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of Embodiment 3 of the present invention;

[0030] Figure 5 A schematic diagram of a state of the sealing method of the present invention;

[0031] Figure 6 It is another state schematic diagram of the sealing method of the present invention. DETAILED DESCRIPTION

[0032] Below, in conjunction with the accompanying drawings and specific embodiments, the present invention is further described:

[0033] like Figure 1 , 2As shown, it is an ultra-high vacuum sealing structure of the first embodiment of the present invention, which includes two butted shells 20 and a metal seal 10. The shell 20 is a hollow structure, and an end wall is formed at one end thereof. The outer surface of the end wall forms a butt joint surface 21, and a through hole 22 is provided on the butt joint surface 21 to communicate with the inner cavity through the end wall. The butt joint surfaces 21 of the two shells 20 are arranged opposite to each other, so that the through holes 22 on the two shells 20 are aligned or roughly aligned. After the two butt joint surfaces 21 are facing each other, a gap is formed between them. The metal seal 10 is placed in the gap between the two butt joint surfaces 21. The metal seal 10 includes two opposite side surfaces 11 and a connecting hole 12. The connecting hole 12 is located in the middle of the metal seal 10, and is formed by a side surface 11 penetrating through the metal seal 10. To the other side surface 11, after the metal seal 10 is placed between the two butt joint surfaces 21, the two side surfaces 11 face the two butt joint surfaces 21 respectively, and the two side surfaces 11 are respectively arranged corresponding to the two butt joint surfaces 21, and a sealing ring 13 and a sealing ring 14 are protrudingly arranged on each side surface 11, wherein the sealing ring 13 and the sealing ring 14 are both arranged around the connecting hole 12, wherein the sealing ring 14 is located on the inner side of the sealing ring 13, so that the sealing ring 14 completely falls into the inside of the sealing ring 13, the protruding height of the sealing ring 13 on the side surface 11 is d1, and the protruding height of the sealing ring 14 on the side surface 11 is d2, wherein d1 is greater than d2, the above-mentioned butt joint surface 21 is set to a plane, and the side surface 11 is also set to a plane, and the housing 20 is arranged on the side surface 11 with the seal 10 During assembly, the butt joint surface 21 and the side surface 11 opposite thereto are arranged in parallel, so that the distance between the sealing ring 14 and the butt joint surface 21 is smaller than the distance between the sealing ring 13 and the butt joint surface 21. In addition, since the distance between the sealing ring 14 and the butt joint surface 21 is relatively small, when the two shells 20 are brought closer to the metal seal 10, the sealing ring 13 first contacts the butt joint surface 21, and the sealing ring 13 is deformed to a certain extent after contacting the butt joint surface 21 by applying external pressure, so as to achieve the sealing of the butt joint portion of the two shells 20. After the two shells 20 clamp the metal seal 10 to complete the sealing, the sealing ring 13 located on the outside is squeezed and deformed, and the sealing ring 14 fails to contact the butt joint surface 21. In this way, at the periphery of the communicating hole 12 and the through hole 22, the sealing ring 13 is deformed by forming The deformed sealing ring 13 forms a sealing structure to achieve partial sealing of the two shells 20. When the leakage rate is detected and it is found that the sealing structure formed by the sealing ring 13 can achieve the ultra-high vacuum sealing requirement, the butt sealing of the two shells 20 is completed; when the sealing structure formed by the sealing ring 13 has defects or other factors cause the ultra-high vacuum sealing requirement to fail to be met, the two shells 20 can be squeezed continuously to further reduce the gap width between the two shells 20, and the sealing ring 13 is squeezed again to make the sealing ring 13 continue to deform while the sealing ring 14 with a relatively small height contacts the butt surface 21 and deforms. In this way, two sealing structures are formed on the periphery of the connecting hole 12 and the through hole 22 by the deformed sealing ring 14 and the sealing ring 13.

[0034] In the above scheme of the present invention, two sealing rings are arranged on the side opposite to the metal seal and the shell, and the gaps between the two sealing rings and the butt joint surface are set to be unequal, so that when the butt joint surface of the shell approaches the metal seal, the two sealing rings can successively contact with the butt joint surface and then deform; during sealing, if the sealing ring that first contacts with the butt joint surface of the shell and deforms fails to meet the sealing requirements, the butt joint surface of the shell can be further brought closer to the sealing ring, so that the other sealing ring contacts with the butt joint surface and then deforms, so that two sealing structures are formed by the two sealing rings, so that the inner cavity of the shell meets the requirements of ultra-high vacuum sealing.

[0035] The above-mentioned sealing ring 13 and sealing ring 14 are arranged to be circular in structure, and the connecting hole 12 is arranged opposite to the two through holes 22 so that the central axes coincide or approximately coincide, and the center of the circle of the extension trajectory of the sealing ring 13 and the sealing ring 14 falls on the central axis of the connecting hole 12; in other embodiments, the sealing ring 13 and the sealing ring 14 can also be arranged to be elliptical or polygonal, etc. In short, the sealing ring 13 and the sealing ring 14 only need to be a closed ring structure that can extend continuously on the side 11 to the periphery of the connecting hole 12.

[0036] In order to make the sealing ring easily deformed by the butt joint surface 21 when it contacts the butt joint surface 21, the sealing ring may be set to a structure with a gradually changing width. Specifically, the cross-sectional width of the sealing ring gradually decreases from the side connected to the side 11 toward the side close to the butt joint surface 21. On the side close to the butt joint surface 21, the sealing ring has a relatively small cross-sectional width. Therefore, when the butt joint surface 21 squeezes the sealing ring, the portion of the sealing ring with a smaller cross-sectional width is easy to deform. The width of the side of the sealing ring close to the butt joint surface 21 may be set to 0 to 1.6 m. m, when the width is 0, it is equivalent to setting the side of the sealing ring close to the butt joint surface 21 to a pointed structure, that is, the two side surfaces of the sealing ring meet at the end of the pointed structure. When the width of the side of the sealing ring close to the butt joint surface 21 is not 0, the side of the sealing ring close to the butt joint surface 21 can be formed into a plane with a width less than 1.6 mm, or the side of the sealing ring close to the butt joint surface 21 can be set to an arc surface, or the side of the sealing ring close to the butt joint surface 21 can be set to a V-shaped structure with a concave middle portion, so that the sealing ring can be deformed when squeezed by the butt joint surface 21.

[0037] The height difference between the sealing ring 13 and the sealing ring 14 is h, preferably within the range of h≥0.2mm. In this way, sufficient deformation space is reserved for the sealing ring 13. That is to say, when the sealing ring 13 is initially deformed, the sealing ring 14 has not yet contacted the docking surface 21. This ensures that when the housing 20 and the metal seal 30 are brought closer in steps, the sealing ring 13 and the sealing ring 14 can successively form two sealing structures.

[0038] like Figure 3As shown, it is an ultra-high vacuum sealing structure of the second embodiment of the present invention. Different from the above-mentioned first embodiment, the present invention respectively sets three sealing rings on the two sides of the metal seal, and the three sealing rings are all around the periphery of the connecting hole, and of any two adjacent sealing rings, the inner sealing ring falls inside the outer sealing ring, and the height of the three sealing rings gradually increases from the inside to the outside. When the butt joint surface of the shell is sealed, the outermost sealing ring contacts the butt joint surface of the shell and deforms. When the detection leak rate fails to meet the requirements, the gap width between the two shell butt joint surfaces is reduced, and the metal seal is compressed so that the middle sealing ring contacts the butt joint surface and deforms. When the detection leak rate has not yet met the requirements, the gap width between the two shell butt joint surfaces is further reduced, and the metal seal is further compressed so that the innermost sealing ring contacts the butt joint surface and deforms. Finally, at the outer periphery of the connecting hole and the through hole, three sealing structures are formed by three sealing rings. In this second embodiment, the height of the three sealing rings gradually increases from the inside to the outside, so that the distances between the three sealing rings and the butt joint surface are different. In fact, the heights of the three sealing rings are not necessarily arranged in a manner that gradually increases from the inside to the outside. The heights of the three sealing rings can be set to gradually increase from the outside to the inside, or the height of the middle sealing ring can be set to the maximum. In short, in the process of gradually reducing the gap between the butt joint surfaces of the two shells, the three sealing rings can contact the butt joint surfaces in sequence and produce deformation.

[0039] like Figure 4As shown, it is an ultra-high vacuum sealing structure of the third embodiment of the present invention, which includes two shells 40 and a metal seal 30, two sealing rings 33 and a sealing ring 34 are respectively arranged on the two side surfaces 31 of the metal seal 30, wherein the sealing ring 33 is located on the outside of the sealing ring 34, and the height of the sealing ring 33 protruding from the side surface 31 is less than the height of the sealing ring 34 protruding from the side surface 31, and the docking surfaces 41 of the two shells 40 are both set to a non-planar structure, wherein the docking surface 41 of the upper shell 40 includes a matching portion 411 corresponding to the upper sealing ring 33 and a matching portion 412 corresponding to the upper sealing ring 34, and the docking surface 41 of the lower shell 40 includes a matching portion 413 corresponding to the lower sealing ring 33 and a matching portion 414 corresponding to the lower sealing ring 34. 14. Since the gap between the fitting part 411 and the fitting part 413 is relatively small, and the gap between the fitting part 412 and the fitting part 414 is relatively large, although the height of the sealing ring 33 is relatively low, when the two shells 40 approach the metal seal 30, the sealing ring 33 first contacts the two fitting surfaces 41. Specifically, the upper sealing ring 33 contacts the fitting part 411, and the lower sealing ring 33 contacts the fitting part 413, so that the sealing ring 33 is first squeezed and deformed. When the sealing structure formed by the sealing ring 33 fails to meet the ultra-high vacuum sealing requirement, the two shells 40 continue to approach the metal seal 30, so that the fitting part 412 squeezes the upper sealing ring 34, and the fitting part 414 squeezes the lower sealing ring 34, and the sealing ring 34 is squeezed and deformed to form a sealing structure.

[0040] At least two sealing rings are respectively arranged on the side surfaces opposite to the two shells on the metal seal of the present invention. When the shell approaches the metal seal, the two sealing rings can be squeezed and deformed by the shell successively to form two sealing structures successively. When the first sealing structure fails to meet the requirements of super-pressure vacuum sealing, the shell gap can be further reduced so that the next sealing ring is deformed into the second sealing structure until the requirements of ultra-high vacuum sealing are met. The sealing structure of the present invention can meet the requirements of ultra-high vacuum sealing. During assembly, it is only necessary to make the shell approach the metal seal in one direction. For example, the two shells can be fixed by bolts, and the bolts are tightened to bring the two shells close to clamp the metal seal. After the first sealing ring is squeezed and deformed, the leakage rate of the sealed chamber is detected. If it does not meet the requirements, the bolts are further tightened so that the subsequent sealing rings can be squeezed and deformed. As long as one sealing ring can meet the requirements of ultra-high vacuum sealing in the sealing structure formed by sufficient deformation, the sealing of the entire system can be achieved. In this way, the installation of the entire system becomes simple and convenient; in addition, the multiple sealing rings on the metal seal can be formed at one time by machining, so that the metal seal is easy to process and form.

[0041] The material of the metal seal of the present invention is oxygen-free copper or other soft metals such as aluminum, indium, silver, etc.

[0042] The sealing method of the present invention is implemented using the above-mentioned ultra-high vacuum sealing structure, which specifically includes the following steps:

[0043] S1. Place the metal seal in the gap formed between the butt surfaces of the two shells so that the connecting holes on the metal seal face the through holes on the two shells;

[0044] S2, bring the two shells closer together to gradually reduce the width of the gap, so that the sealing rings on the two side surfaces closest to the two butt joint surfaces are in contact with the two butt joint surfaces respectively;

[0045] S3, see Figure 5 As shown, the two shells are continuously brought closer together, so that the sealing ring in contact with the butt joint surface in step S2 is deformed. When the next sealing ring is about to approach the butt joint surface, the movement of the two shells is stopped, and the inner cavities of the two shells are connected to form a sealed cavity through the connecting hole.

[0046] S4, evacuate the sealing chamber and check the leakage rate; if the leakage rate meets the requirement, complete the sealing; if the leakage rate does not meet the requirement, proceed to the following step S5;

[0047] S5. See Figure 6 As shown, the two shells are continuously brought closer to clamp the metal seal, so that the next sealing ring in step S3 contacts the mating surface and is deformed.

[0048] The above description is only a preferred embodiment of the present invention, which is a further detailed description of the present invention in combination with a specific preferred embodiment, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Ultra-high vacuum sealing structure, characterized in that: It includes two butted shells and a metal seal; The shell comprises a butt joint surface and a through hole arranged on the butt joint surface and communicating with the inner cavity of the shell, and the butt joint surfaces of the two shells are arranged opposite to each other and a gap is formed therebetween; The metal seal is placed in the gap, and includes two opposite side surfaces and a connecting hole extending from one of the side surfaces to the other side surface, and the two side surfaces face two butt joint surfaces respectively; two or more sealing rings are protruding from the side surfaces and arranged around the connecting holes, and one of any two sealing rings falls into the inside of the other sealing ring; at least two sealing rings on each side surface are at unequal distances from the butt joint surface opposite to the side surface, and at least one sealing ring on the side surface is pressed and fitted with the butt joint surface opposite to the side surface.

2. The ultra-high vacuum sealing structure according to claim 1, characterized in that: The butt joint surface and the side surface are both planes, and in any two adjacent sealing rings, the height of the outer sealing ring is greater than the height of the inner sealing ring.

3. The ultra-high vacuum sealing structure according to claim 2, characterized in that: More than three sealing rings are arranged on the side surface, and the height of the sealing rings increases gradually from the inside to the outside.

4. The ultra-high vacuum sealing structure according to claim 2, characterized in that: The height difference between any two adjacent sealing rings is h, where h≥0.2mm.

5. The ultra-high vacuum sealing structure according to claim 1, characterized in that: The sealing ring is circular, oval or polygonal.

6. The ultra-high vacuum sealing structure according to claim 1, characterized in that: The width of the cross section of the sealing ring gradually decreases from the side connected with the side surface toward the side close to the butt joint surface.

7. The ultra-high vacuum sealing structure according to claim 6, characterized in that: The width of the sealing ring close to the butt joint surface is 0 to 1.6 mm.

8. The ultra-high vacuum sealing structure according to claim 1, characterized in that: The material of the metal seal is oxygen-free copper, aluminum, indium or silver.

9. The ultra-high vacuum sealing structure according to claim 1, characterized in that: The two shells are fixed by bolt connection.

10. A sealing method, characterized in that: Sealing using the ultra-high vacuum sealing structure according to any one of claims 1 to 9 comprises the following steps performed in sequence: S1. Place the metal seal in the gap formed between the butt surfaces of the two shells so that the connecting holes on the metal seal face the through holes on the two shells; S2, bring the two shells closer together to gradually reduce the width of the gap, so that the sealing rings on the two side surfaces closest to the two butt joint surfaces are in contact with the two butt joint surfaces respectively; S3, continue to move the two shells closer together, so that the sealing ring in contact with the butt joint surface in step S2 is deformed, and when the next sealing ring is about to approach the butt joint surface, stop moving the two shells, and the inner cavities of the two shells are connected to form a sealed cavity through the connecting hole; S4, evacuate the sealing chamber and check the leakage rate; if the leakage rate meets the requirement, complete the sealing; if the leakage rate does not meet the requirement, proceed to the following step S5; S5, continue to bring the two shells closer together to clamp the metal seal, so that the next sealing ring in step S3 contacts the butt joint surface and deforms.

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