A static sheet isolation ring integrated component and its application

Abstract

The present application discloses an integrated static blade isolation ring assembly and its application, the technical key points of which are: the internal fixed ring serves as the internal fixed end of the blade; the outer surface of the external fixed ring is fixedly arranged on the inner surface of the isolation ring, and the external fixed ring and the isolation ring together serve as the external fixed end of the blade; m blades are evenly distributed between the internal fixed end and the external fixed end; the blades include: an upper surface, a lower surface, and a vertical surface; the upper surface includes: a first horizontal surface and a second upper inclined surface; the lower surface includes: a third lower inclined surface and a fourth horizontal surface; the first horizontal surface is adjacent to the second upper inclined surface and the third lower inclined surface respectively; the fourth horizontal surface is adjacent to the third lower inclined surface and the vertical surface respectively; the vertical surface is adjacent to the fourth horizontal surface and the second upper inclined surface respectively; the second upper inclined surface is parallel to the third lower inclined surface. The technical solution of the present application can eliminate air gap backflow and optimize molecular flow conditions.

Description

Technical Field

[0001] The present application relates to the field of static plate isolation ring assemblies, and more specifically, to an integrated static plate isolation ring assembly and applications thereof. Background Art

[0002] like Figure 1 As shown in CN114593075B, the turbomolecular pump mainly includes: pump housing, turbine, static piece, main shaft assembly, stator assembly, base, isolation ring, etc. The turbomolecular pump pumps gas through a combination of high-speed rotating multi-stage turbine rotor blades and static blades, and produces a very high compression ratio for the pumped gas in the molecular flow area, thereby obtaining the high and ultra-high vacuum environment required for the closed cavity.

[0003] The isolating ring is connected to the static piece to support and stabilize the static piece. The static piece and the isolating ring are key core components that affect the performance indicators of the molecular pump, such as the pumping speed and compression ratio. Among them, the key parameters such as the angle, tooth length, and number of teeth of the static piece parts have a significant impact on the core indicators of the molecular pump; and the isolating ring has a significant impact on the tooth clearance between the dynamic and static pieces.

[0004] Therefore, for molecular pumps, the improvement of the isolation ring and the static plate is a very important aspect.

[0005] For molecular pump stators and isolation rings, the existing technology is summarized as shown in Table 1:

[0006] Table 1

[0007]

[0008] From the above analysis, it can be seen that the existing technologies are mostly aimed at the research of magnetic suspension molecular pumps with a diameter of DN60~DN83. There are relatively few studies on static pieces with a large diameter such as DN160 to DN400.

[0009] For magnetic levitation molecular pumps with a diameter of DN160 to DN400, the static plate and isolation ring components are still designed and processed separately. There are the following problems in processing and design:

[0010] (1) Processing: For static pieces, they are generally processed by lathe plus saw blade or 5-axis CNC. When the static piece is processed by lathe plus saw blade, it is necessary to customize the saw blade separately, which is easy to produce blade vibration during the processing, resulting in poor processing effect. When the 5-axis CNC method is used for processing, the processing unit price and working hours are high, and the processing cost has no advantage. The isolation ring is processed by a lathe. Due to the annular structure of the isolation ring, the diameter to wall thickness ratio is extremely large, and the thin-walled parts are greatly deformed during processing, resulting in low product yield.

[0011] (2) Design:

[0012] 2.1, The static plate and the isolation ring are two independent parts, and there will inevitably be a gap between them when they are assembled. During the operation of the turbomolecular pump, gas molecules are prone to flow back through the gap between the isolation ring and the static plate, causing the key performance of the molecular pump, such as pumping speed and compression ratio, to decrease.

[0013] 2.2, the first static piece 1-1 to the seventh static piece 1-7 are similar, so the seventh static piece 1-7 is analyzed below.

[0014] Figure 2 The force analysis diagram of the seventh static piece 1-7 - static displacement is shown. Since the static piece is separated from the isolation ring, the static piece has a low strength and is greatly affected by the impact of external gas, which is prone to resonance impact.

[0015] Figure 3 The modal analysis diagram of the seventh static piece 1-7 is shown. The material of the seventh static piece 1-7 is 6061 aluminum alloy, the instantaneous pressure difference is 100Pa (impact pressure), and the calculated modes of the first 10 orders (the 10th order frequency 530Hz is greater than 350Hz, and the pump operating frequency is 350Hz) are shown in Table 2: Among them, the maximum displacement is 36.77mm at the 8th order 380.05Hz, and the instantaneous 100Pa impact pressure will cause the distance between the moving piece and the static piece to exceed 2.80mm at this time, and the moving and static pieces will interfere, and the molecular pump will have the risk of failure.

[0016] Table 2

[0017]

[0018] (3) There is an air gap between the static plate and the isolation ring, and backflow occurs during operation.

[0019] Therefore, how to improve the design of the stator and isolation ring of large-diameter magnetic levitation molecular pumps such as DN160 to DN400 has become a technical problem that needs to be solved urgently in the field of turbomolecular pumps. Summary of the invention

[0020] The purpose of the present application is to provide an integrated static plate isolation ring assembly in view of the above-mentioned deficiencies in the prior art.

[0021] Another object of the present application is to provide an application of a static plate isolation ring integrated assembly.

[0022] The technical solution of this application is as follows:

[0023] A static plate isolation ring integrated assembly, comprising: an inner fixing ring, an outer fixing ring, an isolation ring, and m blades; m represents a natural number greater than or equal to 20;

[0024] Wherein, the inner fixing ring, the outer fixing ring and the isolation ring are concentrically arranged;

[0025] The inner fixing ring serves as the inner fixing end of the blade; the outer surface of the outer fixing ring is fixedly arranged on the inner surface of the isolating ring, and the outer fixing ring and the isolating ring serve together as the outer fixing end of the blade; m blades are evenly distributed between the inner fixing end and the outer fixing end;

[0026] The blade includes: an upper surface, a lower surface, and a vertical surface; the upper surface includes: a first horizontal surface and a second upper inclined surface; the lower surface includes: a third lower inclined surface and a fourth horizontal surface; the first horizontal surface is adjacent to the second upper inclined surface and the third lower inclined surface respectively; the fourth horizontal surface is adjacent to the third lower inclined surface and the vertical surface respectively; the vertical surface is adjacent to the fourth horizontal surface and the second upper inclined surface respectively; the second upper inclined surface is parallel to the third lower inclined surface;

[0027] Among them, assuming that the radius of the outer side of the inner fixing ring is r0, and the radius of the inner side of the outer fixing ring is r1, then the horizontal cross-sectional area of ​​the ring between the inner fixing ring and the outer fixing ring is π (r1 2 - r0 2 ); The projection area of ​​the upper surface of m blades on the horizontal plane is γπ (r1 2 - r0 2 );

[0028] Wherein, the inclination angle between the second upper inclined plane and the first horizontal plane is [10°, 80°];

[0029] Among them, γ is in the range of [0.95, 1.0].

[0030] Furthermore, the thickness range of the external fixing ring is: [2mm, 4mm], and the thickness of the isolation ring is: [5mm, 45mm].

[0031] Further, the outer upper portion of the blade is fixed to the outer fixing ring, and the outer lower portion of the blade is fixed to the isolation ring.

[0032] Furthermore, an inclination angle between the second upper inclined surface and the first horizontal plane is 16°.

[0033] Furthermore, the static plate isolation ring integrated component is made by die casting.

[0034] An application of a static plate isolation ring integrated component, wherein the static plate isolation ring integrated component is applied to a magnetic suspension molecular pump.

[0035] Furthermore, the opening diameter of the magnetic levitation molecular pump is DN160~DN400.

[0036] The beneficial effects of this application are:

[0037] (1) The basic inventive concept of the present application is to "fix and connect the external fixing ring and the isolation ring into one body", which significantly improves the rigidity and modal properties of the component.

[0038] (2) This application proposes an idea for improving the static piece for large-caliber molecular pumps:

[0039] 2.1 How to avoid backflow. Based on numerical analysis, it is found that the contact surface between the static plate and the isolation ring has a low-pressure area above and a high-pressure area below. Due to the air gap between the static plate and the isolation ring, there will inevitably be a phenomenon of airflow backflow. For the molecular pump, its purpose is to pump away the gas, and backflow will cause the gas to return, which is not conducive to the operation of the molecular pump.

[0040] To address this issue, the present application adopts the design of "an external fixing ring and an isolating ring acting together as the external fixing end of the blade, the external upper part of the blade is fixed to the external fixing ring, and the external lower part of the blade is fixed to the isolating ring", thereby avoiding the air gap between the isolating ring and the static sheet, and thus avoiding the backflow phenomenon.

[0041] 2.2, How to improve the extraction efficiency.

[0042] For molecular pumps, improving the pumping efficiency must be the focus of optimization in the field of molecular pumps.

[0043] In response to this problem, the present application states that “the blades include: an upper surface, a lower surface, and a vertical surface; the upper surface includes: a first horizontal plane and a second upper inclined plane; the lower surface includes: a third lower inclined plane and a fourth horizontal plane; the first horizontal plane is adjacent to the second upper inclined plane and the third lower inclined plane, respectively; the fourth horizontal plane is adjacent to the third lower inclined plane and the vertical plane, respectively; the vertical plane is adjacent to the fourth horizontal plane and the second upper inclined plane, respectively; the second upper inclined plane is parallel to the third lower inclined plane”, that is, through the shape design of the blades, a bell-mouth structure design is formed at the lower part of the adjacent blades, which optimizes the flow direction of the gas molecules and thereby improves the air extraction efficiency of the static plate.

[0044] 2.3, how to strike a balance between compression ratio and pumping efficiency. γ in [0.95, 1.0] is a more reasonable choice for large-caliber molecular pump stators. The setting of the vertical surface 1045 is an important design to make γ close to 1.0.

[0045] Taking the DN400 molecular pump blade as an example, the relationship between γ and compression ratio and pumping efficiency is as follows:

[0046] (1) As γ increases, the exhaust efficiency first increases slowly and then decreases continuously;

[0047] (2) The compression ratio continues to increase as γ increases;

[0048] In the stage of γ≤1.0, as γ increases, the increase in the pumping efficiency is not obvious, but the increase in the compression ratio is large. Therefore, γ is selected in [0.95, 1.0].

[0049] The above analysis shows that, unlike the design of small-diameter molecular pumps, such as US20080317590A1 and CN202091252U, γ is generally around 0.6, which is significantly less than 1.0. The reason is that the pumping efficiency and compression ratio required by small-diameter molecular pumps do not need to be too high. For large-diameter molecular pumps, it is necessary to balance the two core indicators of pumping efficiency and compression ratio. At the same time, when γ is greater than 1.0, the difficulty of manufacturing is significantly increased.

[0050] In summary, it is appropriate to select [0.95, 1.0] for γ in this application.

[0051] 2.4, limitation of reflux angle.

[0052] As shown in Table 3 below, when the reverse flow angle increases, the Ho coefficient of the blade row shows an increasing trend, that is, the pumping speed increases and the compression ratio component decreases.

[0053] Table 3

[0054]

[0055] As for the backflow angle δ, it is related to the inclination angles β, γ, etc. between the second upper inclined surface and the first horizontal plane.

[0056] When β is between 10° and 80°, γ is between 0.95 and 1.0, and δ is generally between 82.8 and 115.5°. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The present application is further described in detail below in conjunction with the embodiments in the accompanying drawings, but does not constitute any limitation to the present application.

[0058] Figure 1 It is a structural diagram of a turbomolecular pump of the prior art.

[0059] Figure 2 It is a schematic diagram of force analysis of the seventh static piece in the prior art.

[0060] Figure 3 It is a modal analysis diagram of the seventh static piece of the prior art.

[0061] Figure 4 It is a three-dimensional design schematic diagram of a static plate isolation ring integrated component of a large-caliber molecular pump of the present application.

[0062] Figure 5 It is a schematic diagram of the three-dimensional design of the blade of this application.

[0063] Figure 6 It is a three-dimensional design schematic diagram of the blade of the present application from another perspective.

[0064] Figure 7 It is a schematic plan view of the lower surface of a static plate isolation ring integrated component of a large-caliber molecular pump of the present application.

[0065] Figure 8 It is a schematic diagram of the force and displacement of the seventh static plate-isolation ring integrated assembly of the present application.

[0066] Fig. 9 It is a schematic diagram of the design of the bell-mouth opening on the lower side of adjacent blades of the present application.

[0067] The reference numerals are as follows:

[0068] A first static film 1-1, a second static film 1-2, a third static film 1-3, a fourth static film 1-4, a fifth static film 1-5, a sixth static film 1-6, and a seventh static film 1-7;

[0069] A first isolation ring 2-1, a second isolation ring 2-2, a third isolation ring 2-3, a fourth isolation ring 2-4, a fifth isolation ring 2-5, a sixth isolation ring 2-6, and a seventh isolation ring 2-7;

[0070] Static blade isolation ring integrated assembly 100, inner fixing ring 101, outer fixing ring 102, isolation ring 103, blade 104;

[0071] A first horizontal plane 1041 , a second upper inclined plane 1042 , a third lower inclined plane 1043 , a fourth horizontal plane 1044 , and a vertical plane 1045 . DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0073] The large-diameter molecular pump described in this application refers to a molecular pump with a diameter of DN160~DN400.

[0074] The reverse flow angle δ mentioned in the present application refers to the change angle of the molecular flow in adjacent blades.

[0075] <Example 1: Design of an integrated assembly of a static plate isolation ring for a large-caliber molecular pump>

[0076] <1. Structural design>

[0077] like Figure 4 As shown, a static plate isolating ring integrated assembly 100 of a large-caliber molecular pump includes an inner fixing ring 101, an outer fixing ring 102, an isolating ring 103, and m blades 104, which are arranged concentrically; m represents a natural number greater than or equal to 20. The outer fixing ring 102 is fixedly connected to the isolating ring 103; the inner fixing ring 101 serves as the inner fixing end of the blade 104; the outer fixing ring 102 and the isolating ring 103 serve together as the outer fixing end of the blade 104; the m blades 104 are evenly distributed between the inner fixing end and the outer fixing end (circular array).

[0078] Assuming that the radius of the outer side of the inner fixing ring is r0 and the radius of the inner side of the outer fixing ring 102 is r1, the horizontal cross-sectional area of ​​the ring between the inner fixing ring 101 and the outer fixing ring 102 is π (r1 2 - r0 2 ).

[0079] like Figure 5 As shown, the blade 104 includes: an upper surface, a lower surface, and a vertical surface 1045;

[0080] The upper surface includes: a first horizontal surface 1041 and a second upper inclined surface 1042;

[0081] The lower surface includes: a third lower inclined surface 1043 and a fourth horizontal surface 1044;

[0082] The first horizontal plane 1041 is adjacent to the second upper inclined plane 1042 and the third lower inclined plane 1043 respectively; the fourth horizontal plane 1044 is adjacent to the third lower inclined plane 1043 and the vertical plane 1045 respectively; the vertical plane 1045 is adjacent to the fourth horizontal plane 1044 and the second upper inclined plane 1042 respectively;

[0083] The second upper inclined surface 1042 is parallel to the third lower inclined surface 1043;

[0084] The projection area of ​​the upper surface of the m blades 104 on the horizontal plane is γπ (r1 2 - r0 2 ), the inclination angle is generally between 10°~80°, and γ=0.95~1.0.

[0085] The optimized design of the static plate isolation ring die-casting assembly of the large-caliber molecular pump of this application is described as follows:

[0086] (1) This application is applicable to molecular pumps with a diameter of DN160 to DN400.

[0087] (2) For a molecular pump, the thickness of the external fixing ring 102 is generally between 2 and 4 mm; and the thickness of the isolation ring 103 is between 5 mm and 45 mm. The external fixing ring 102 and the isolation ring 103 are used together as the external fixing end of the blade 104, that is, the upper part of the outer part of the blade is fixed to the external fixing ring 102, and the lower part of the outer part of the blade is fixed to the isolation ring. Through the above design, the backflow problem is avoided.

[0088] (3) Design of γ and vertical surface 1045. Through numerical simulation, it is found that the change of γ will affect the two core indicators of pumping efficiency and compression ratio. Different from small-diameter molecular pumps (small-diameter molecular pumps γ is generally 0.6), large-diameter molecular pumps need to balance the two core indicators of pumping efficiency and compression ratio. In this regard, this application selects a design with γ close to 1.0 through the setting of vertical surface 1045.

[0089] (4) If Fig. 9 As shown in (shown at A), the blade adopts the design of "third lower inclined surface 1043, fourth horizontal surface 1044, vertical surface 1045", and the lower side of adjacent blades can form a bell-mouth opening design, thereby improving the exhaust efficiency of the static plate.

[0090] (5) As shown in Table 4, the inclination angle between the second upper inclined surface 1042 and the first horizontal plane 1041 is 16°. According to the analysis of the first five frequencies after the optimization of the above-mentioned static plate assembly, the first-order lowest frequency is 368 Hz, which is greater than the operating frequency of 350 Hz. At the same time, the pump operating frequency is reduced due to the impact, which will be further away from the resonance range, and the vacuum assembly will operate more stably.

[0091] Table 4

[0092]

[0093] The above-mentioned embodiments are preferred implementation modes of the present application and are only used to facilitate the explanation of the present application. They are not intended to limit the present application in any form. Any person with ordinary knowledge in the relevant technical field, if they do not depart from the scope of the technical features of the present application, can make equivalent embodiments by making partial changes or modifications to the technical contents disclosed in the present application and do not depart from the technical features of the present application. All of these still fall within the scope of the technical features of the present application.

Claims

1. A static sheet isolation ring integrated assembly, characterized in that: include: An inner fixing ring, an outer fixing ring, an isolating ring, and m blades; m represents a natural number greater than or equal to 20; Wherein, the inner fixing ring, the outer fixing ring and the isolation ring are concentrically arranged; The inner fixing ring serves as the inner fixing end of the blade; the outer surface of the outer fixing ring is fixedly arranged on the inner surface of the isolating ring, and the outer fixing ring and the isolating ring serve together as the outer fixing end of the blade; m blades are evenly distributed between the inner fixing end and the outer fixing end; The blade includes: an upper surface, a lower surface, and a vertical surface; the upper surface includes: a first horizontal surface and a second upper inclined surface; the lower surface includes: a third lower inclined surface and a fourth horizontal surface; the first horizontal surface is adjacent to the second upper inclined surface and the third lower inclined surface respectively; the fourth horizontal surface is adjacent to the third lower inclined surface and the vertical surface respectively; the vertical surface is adjacent to the fourth horizontal surface and the second upper inclined surface respectively; the second upper inclined surface is parallel to the third lower inclined surface; Among them, assuming that the radius of the outer side of the inner fixing ring is r0, and the radius of the inner side of the outer fixing ring is r1, then the horizontal cross-sectional area of ​​the ring between the inner fixing ring and the outer fixing ring is π (r1 2 - r0 2 ); The sum of the projection areas of the upper surfaces of the m blades on the horizontal plane is γπ (r1 2 - r0 2 ); Wherein, the inclination angle between the second upper inclined plane and the first horizontal plane is [10°, 80°]; Among them, γ is in the range of [0.95, 1.0].

2. The stator isolation ring integrated assembly according to claim 1, characterized in that: The thickness range of the external fixing ring is: [2mm, 4mm], and the thickness of the isolation ring is: [5mm, 45mm].

3. The stator isolation ring integrated assembly according to claim 1 or 2, characterized in that: The outer upper part of the blade is fixed to the outer fixing ring, and the outer lower part of the blade is fixed to the isolation ring.

4. The stator isolation ring integrated assembly according to claim 1, characterized in that: The inclination angle between the second upper inclined surface and the first horizontal plane is 16°.

5. The stator isolation ring integrated assembly according to claim 1, characterized in that: The static plate isolation ring integrated component is made by die casting.

6. An application of a static plate isolation ring integrated assembly, characterized in that: The stator isolation ring integrated assembly is the stator isolation ring integrated assembly as claimed in any one of claims 1 to 5, and is applied to a magnetic levitation molecular pump.

7. The use of a static plate isolation ring integrated assembly according to claim 6, characterized in that: The opening diameter of the magnetic suspension molecular pump is DN160-DN400.

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