Molecular pump

Abstract

The embodiment of the utility model relates to the field of vacuum equipment. More specifically, the utility model relates to a molecular pump. A molecular pump includes: a housing having an air inlet and an air outlet; the motor is fixedly arranged in the shell; the turbine component is arranged in the shell and fixedly arranged on a rotating shaft of the motor in a sleeving manner; the air exhaust channel is formed between the turbine part and the inner wall of the shell and is communicated with the air inlet and the air outlet; the turbine component comprises a turbine body, a plurality of layers of moving blade sets and a plurality of first spiral grooves, wherein the turbine body is provided with an air exhaust part, a first compression part and a second compression part which are sequentially connected, and the first spiral grooves are evenly formed in the first compression part of the turbine body at intervals in the circumferential direction. The turbine component includes a plurality of second helical grooves. The molecular pump has higher compression ratio and better backflow inhibition capability, and is more suitable for long-term stable operation.

Description

Technical Field

[0001] The embodiments of this utility model relate to the field of vacuum equipment. More specifically, this utility model relates to a molecular pump. Background Technology

[0002] Molecular pumps, as key equipment in the field of high vacuum technology, are widely used in cutting-edge fields such as semiconductor manufacturing, materials science research, aerospace, and nuclear energy technology. Their superior performance, especially their high pumping speed, high compression ratio, and low backflow characteristics, is crucial for maintaining and creating extreme vacuum environments.

[0003] Existing molecular pumps mainly consist of a housing with an inlet and an outlet, a motor fixed inside the housing, and a turbine component housed inside the housing and fixedly mounted on the motor shaft. An extraction channel is formed between the turbine component and the inner wall of the housing, connecting the inlet and outlet. During operation, the motor drives the turbine component to rotate at high speed within the housing. The rotating blades of the turbine component continuously cut and compress gas molecules entering from the inlet. These compressed gas molecules are then guided along the extraction channel to the outlet, where they are further propelled by the turbine component and guided by the inner wall of the housing, ensuring that the gas molecules are efficiently and orderly discharged from the pump.

[0004] Despite significant progress made in existing molecular pumps, they still face two major challenges: first, the room for improvement in compression ratio is limited, making it difficult to meet increasingly stringent vacuum requirements; second, backflow is difficult to control effectively, affecting the stability and long-term operating efficiency of molecular pumps. Utility Model Content

[0005] In order to solve one or more of the technical problems mentioned above, this utility model provides a molecular pump, which aims to improve the turbine structure of existing molecular pumps, thereby effectively increasing the compression ratio of the molecular pump while reducing its backflow, which is beneficial to maintaining the long-term stable operation of the molecular pump.

[0006] According to the present invention, a molecular pump is provided, comprising: a housing having an inlet and an outlet; a motor fixedly disposed within the housing; a turbine component disposed within the housing and fixedly sleeved on the shaft of the motor; and an extraction channel formed between the turbine component and the inner wall of the housing and communicating with the inlet and outlet; wherein the turbine component includes a turbine body having an extraction section, a first compression section and a second compression section sequentially connected, a multi-layer moving blade assembly spaced axially on the extraction section of the turbine body, and a plurality of first helical grooves spaced evenly circumferentially on the first compression section of the turbine body; the turbine component includes a plurality of second helical grooves spaced evenly circumferentially on the second compression section of the turbine body, or the inner wall of the housing is provided with a plurality of second helical grooves evenly arranged circumferentially and surrounding the second compression section of the turbine body.

[0007] Furthermore, the radial dimension of the extraction section is smaller than the radial dimension of the first compression section, so that the flow area of ​​the extraction passage at the location of the first compression section of the turbine body is smaller than its flow area at the location of the extraction section of the turbine body. The radial dimension of the first compression section is larger than the radial dimension of the second compression section, but the flow area of ​​the extraction passage at the location of the first compression section of the turbine body is larger than its flow area at the location of the second compression section of the turbine body.

[0008] Furthermore, the number of the second spiral grooves is 19, the spiral angle is 32°, and the ratio of their total cross-sectional area to the cross-sectional area at the gas inlet of the molecular pump is 1:5.5.

[0009] Furthermore, the number of the first spiral grooves is 17, the spiral angle is 32°, and the ratio of their total cross-sectional area to the cross-sectional area at the gas inlet of the molecular pump is 1:4.7.

[0010] Furthermore, the axial dimension of the second compression section is larger than the axial dimension of the first compression section.

[0011] Furthermore, each layer of the moving blade assembly includes a plurality of moving blades evenly spaced along the circumference outside the turbine body.

[0012] Furthermore, in the axial direction, the moving blades farther from the first helical groove have a greater thickness, a greater difference between their inner and outer diameters, and a smaller number compared to the moving blades closer to the first helical groove.

[0013] Furthermore, the turbine component is made of stainless steel, aluminum alloy, titanium alloy, or ceramic material.

[0014] Furthermore, the molecular pump is a magnetically levitated molecular pump.

[0015] This invention discloses a molecular pump, the main improvement of which lies in the application of a novel turbine structure. Compared with existing turbine components, this turbine component, in addition to having an air extraction section of the turbine body and a multi-layered moving blade assembly located in the air extraction section, also includes a first compression section and a second compression section of the turbine body, as well as multiple first helical grooves on the first compression section of the turbine body and multiple second helical grooves on the second compression section or the housing of the turbine body. In operation, the motor drives the turbine component to rotate at high speed within the housing. The multi-layered moving blades of the turbine component continuously cut and compress gas molecules entering from the inlet as they rotate, causing the gas molecules to travel along the air extraction channel through the first and second helical grooves and exit from the outlet. The first and second helical grooves further compress the gas molecules along their path, increasing the compression ratio of the molecular pump during operation. Furthermore, the additional first and second helical grooves also increase the overall length of the air extraction channel, making it easier to reduce backflow during operation and facilitating long-term, stable operation of the molecular pump.

[0016] Experimental verification shows that, compared with existing turbine components, this turbine component has a stronger ability to capture gas molecules such as hydrogen and helium, and the degree of improvement in compression ratio is more significant. Attached Figure Description

[0017] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0018] Figure 1 A schematic diagram of the molecular pump according to an embodiment of the present invention is shown;

[0019] Figure 2 A cross-sectional view of the molecular pump in the axial direction is shown when the second helical groove is provided on the turbine body;

[0020] Figure 3 A cross-sectional view of the molecular pump in the axial direction is shown when the second helical groove is provided on the housing;

[0021] Figure 4 A perspective view of the turbine component of a molecular pump according to an embodiment of the present invention is shown.

[0022] Explanation of reference numerals in the attached drawings: 100, molecular pump; 1, housing; 11, air inlet; 12, air outlet; 3, turbine component; 31, extraction section; 32, first compression section; 321, first helical groove; 33, second compression section; 322, second helical groove; 4, extraction channel; 5, turbine body; 51, moving blade assembly; 52, fixed blade assembly. Detailed Implementation

[0023] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0024] This utility model embodiment provides a molecular pump 100, see reference Figure 1 The molecular pump 100 is a mechanical vacuum pump that relies on momentum transfer to achieve gas extraction, and it is widely used in industries such as semiconductor electronics, semiconductor lighting, flat panel displays, solar cells, and optical components. The turbomolecular pump 100, in particular, is widely used due to its high pumping speed, oil-free operation, and simple maintenance. The molecular pump 100 in this application is preferably a magnetically levitated molecular pump 100, which has a longer bearing life and allows the rotor to reach higher speeds more easily, thus improving the compression ratio of gas molecules.

[0025] Reference Figure 2 , Figure 3 as well as Figure 4 The molecular pump 100 includes a housing 1 having an inlet 11 and an outlet 12, a motor (not shown, also called an electric motor) fixedly disposed within the housing 1, a turbine component 3 disposed inside the housing 1 and sleeved on the shaft of the motor, and an extraction passage 4 formed between the turbine component 3 and the inner wall of the housing 1 and communicating between the inlet 11 and the outlet 12. The turbine component 3 includes a turbine body 5 having an extraction section 31, a first compression section 32 and a second compression section 33 connected in sequence, and a multi-layer moving blade assembly 51 disposed axially spaced on the extraction section 31 of the turbine body 5.

[0026] To increase the compression ratio of the molecular pump 100, the turbine component 3 further includes a plurality of first helical grooves 321 evenly spaced along the circumference on the first compression section 32 of the turbine body 5, and a plurality of second helical grooves 322 evenly spaced along the circumference on the second compression section 33 of the turbine body 5. It should be noted that the plurality of second helical grooves 322 may not be provided on the turbine body 5, but rather evenly spaced along the circumference on the inner wall of the housing 1 and surrounding the second compression section 33 of the turbine body 5.

[0027] Compared with existing turbine components 3, this turbine component 3, in addition to having an extraction section 31 of the turbine body 5 and a multi-layer moving blade assembly 51 provided in the extraction section 31, also has a first compression section 32 and a second compression section 33 of the turbine body 5, as well as multiple first spiral grooves 321 provided on the first compression section 32 of the turbine body 5, and multiple second spiral grooves 322 provided on the second compression section 33 of the turbine body 5 or the housing 1. In use, the motor drives the turbine component 3 to rotate at high speed in the housing 1. As the turbine component 3 rotates, the multi-layer moving blades continuously cut and compress the gas molecules entering from the inlet 11, causing the gas molecules to pass through the first spiral grooves 321 and the second spiral grooves 322 along the extraction channel 4 and be discharged from the outlet 12. The first spiral grooves 321 and the second spiral grooves 322 can further compress the gas molecules along the way and increase the compression ratio of the molecular pump 100 during operation. In addition, the additional introduction of the first spiral groove 321 and the second spiral groove 322 can also increase the overall length of the pumping channel 4, which makes it easier to reduce the backflow of the molecular pump 100 during operation and helps to maintain the long-term and stable operation of the molecular pump 100.

[0028] In this embodiment, the radial dimension of the extraction section 31 is smaller than the radial dimension of the first compression section 32, so that the flow area of ​​the extraction channel 4 at the location of the first compression section 32 in the turbine body 5 is smaller than its flow area at the location of the extraction section 31 in the turbine body 5. The radial dimension of the first compression section 32 is larger than the radial dimension of the second compression section 33, but the flow area of ​​the extraction channel 4 at the location of the first compression section 32 in the turbine body 5 is larger than its flow area at the location of the second compression section 33 in the turbine body 5. Thus, the extraction channel 4 has multiple inflection points, and its flow area gradually decreases along the flow direction of gas molecules, ensuring that the molecular pump 100 can not only effectively improve the compression ratio, but also effectively suppress backflow.

[0029] In this embodiment, the number of first spiral grooves 321 is 17, the spiral angle is 32°, and the ratio of their total cross-sectional area to the cross-sectional area at the gas inlet of the molecular pump 100 is 1:4.7. The number of second spiral grooves 322 is 19, the spiral angle is 32°, and the ratio of their total cross-sectional area to the cross-sectional area at the gas inlet of the molecular pump 100 is 1:5.5. Extensive experiments have shown that when the first spiral grooves 321 and the second spiral grooves 322 meet the above conditions, the compression ratio and backflow suppression effect of the molecular pump during operation can be maximized.

[0030] In this embodiment, the axial dimension of the second compression section 33 is larger than the axial dimension of the first compression section 32. Gas molecules undergo a final compression at the second compression section 33 before being discharged from the molecular pump 100. Given a fixed internal space within the molecular pump 100, increasing the axial dimension of the second compression section 33 further reduces backflow when gas molecules are discharged from the molecular pump 100, while also enhancing the compressibility of the gas molecules, ultimately increasing the pumping speed and compression ratio of the molecular pump 100.

[0031] In this embodiment, each layer of moving blades includes multiple moving blades evenly spaced along the circumference outside the turbine body 5, specifically three layers, with 16, 20, and 33 moving blades sequentially along the gas molecule transport direction. This facilitates the molecular pump 100 in extracting gas at the inlet 11 and also enhances the cooling effect of the moving blades, thereby increasing their service life. From a material perspective, when the molecular pump 100 is working, the moving blades cut gas molecules at high speed, generating a large amount of heat energy. The moving blades are in a high-temperature region for a long time, so the turbine component 3 can be made of high-temperature resistant materials such as stainless steel, aluminum alloy, titanium alloy, or ceramic materials, thereby improving the service life of the moving blades.

[0032] In this embodiment, the inner wall of the housing 1 is provided with a multi-layer fixed blade group 52 arranged at intervals along the axial direction, and a multi-layer moving blade group 51 is alternately arranged in the multi-layer fixed blade group 52 along the axial direction. The high-speed rotating moving blades transfer momentum through collisions with gas molecules, while the fixed blades help guide the flow direction of gas molecules. Through the cooperation of the moving and fixed blades, the pumping efficiency of the molecular pump 100 can be improved.

[0033] In this embodiment, in the axial direction, compared with the moving blades near the first helical groove 321, the moving blades farther away from the first helical groove 321 have a greater thickness, a larger difference between their inner and outer diameters (i.e., the difference between the outer diameter and the inner diameter), and a smaller number. This gradual design of the thickness, number, and inner and outer diameter difference of the moving blades in the axial direction is beneficial for the stepwise compression and acceleration of the pumped gas, forming a smoother gas flow path, reducing the resistance, backflow, and energy loss of gas molecules during the flow process, and thus improving the pumping efficiency and compression ratio of the molecular pump 100.

[0034] In summary, the molecular pump 100, due to the use of the improved turbine component 3, has a higher compression ratio and better backflow suppression capability, making it more suitable for long-term stable operation.

[0035] In the foregoing description of this application, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "linked" should be interpreted broadly. For example, the term "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this application, those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0036] Based on the above description of this application, those skilled in the art will also understand that the terms used, such as "inner," "outer," "axial," "radial," and "circumferential," which indicate orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings of this application. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in the specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as a limitation on the present invention.

[0037] Furthermore, the terms "first" or "second," etc., used in this application to refer to numbers or ordinal numbers are for descriptive purposes only and should not be construed as explicitly or implicitly indicating relative importance or specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0038] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention. The appended claims are intended to define the scope of protection of the present invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A molecular pump, characterized in that, include: The housing has an air inlet and an air outlet; The motor is fixedly installed inside the housing; A turbine component, which is located inside the housing and fixedly mounted on the motor shaft; as well as An air extraction passage is formed between the turbine component and the inner wall of the housing and connects the air inlet and the air outlet; The turbine component includes a turbine body having an extraction section, a first compression section and a second compression section connected in sequence, a multi-layer moving blade assembly spaced axially on the extraction section of the turbine body, and a plurality of first spiral grooves spaced circumferentially on the first compression section of the turbine body. The turbine component includes a plurality of second spiral grooves evenly spaced along the circumference on the second compression section of the turbine body, or the inner wall of the housing is provided with a plurality of second spiral grooves evenly arranged along the circumference and surrounding the second compression section of the turbine body.

2. The molecular pump according to claim 1, characterized in that, The radial dimension of the extraction section is smaller than the radial dimension of the first compression section, such that the flow area of ​​the extraction channel at the location of the first compression section of the turbine body is smaller than its flow area at the location of the extraction section of the turbine body. The radial dimension of the first compression section is larger than the radial dimension of the second compression section, but the flow area of ​​the extraction channel at the location of the first compression section of the turbine body is larger than its flow area at the location of the second compression section of the turbine body.

3. The molecular pump according to claim 1, characterized in that, The second spiral groove has 19 grooves, a spiral angle of 32°, and a total cross-sectional area ratio of 1:5.5 to the cross-sectional area at the gas inlet of the molecular pump.

4. The molecular pump according to claim 3, characterized in that, The number of the first spiral grooves is 17, the spiral angle is 32°, and the ratio of their total cross-sectional area to the cross-sectional area at the gas inlet of the molecular pump is 1:4.

7.

5. The molecular pump according to claim 1, characterized in that, The axial dimension of the second compression section is greater than that of the first compression section.

6. The molecular pump according to claim 1, characterized in that, Each layer of the moving blade assembly includes multiple moving blades that are evenly spaced along the circumference outside the turbine body.

7. The molecular pump according to claim 1, characterized in that, The inner wall of the housing is provided with multiple layers of fixed blade groups arranged at intervals along the axial direction, and the multiple layers of moving blade groups are alternately arranged in the multiple layers of fixed blade groups along the axial direction.

8. The molecular pump according to claim 1, characterized in that, In the axial direction, the moving blades farther from the first helical groove have a greater thickness, a greater difference between their inner and outer diameters, and a smaller number compared to the moving blades closer to the first helical groove.

9. The molecular pump according to claim 1, characterized in that, The turbine component is made of stainless steel, aluminum alloy, titanium alloy, or ceramic material.

10. The molecular pump according to claim 1, characterized in that, The molecular pump is a magnetically levitated molecular pump.

Images