Composite multi-compression mechanism vacuum pump with high compression ratio and high pumping speed

Abstract

The invention provides a composite multi-compression mechanism vacuum pump with high compression ratio and high pumping speed, a multi-compression mechanism comprises a turbine, traction wheels and a vortex blade array, the traction wheels are divided into a first-stage traction wheel and a second-stage traction wheel, a first-stage exhaust port and a second-stage exhaust port are formed in a base, and a valve is arranged on the first-stage exhaust port; in the first air exhaust stage, the valve is opened, most of air flows through the turbine and the first-stage traction wheel to be exhausted from a first-stage exhaust port, and a small part of air flows through the turbine, the first-stage traction wheel, the second-stage traction wheel and the vortex blade row in sequence to be exhausted from a second-stage exhaust port; and in the second air exhaust stage, the valve is closed, and the air flows through the turbine, the first-stage traction wheel, the second-stage traction wheel and the vortex blade row and is exhausted from a second-stage exhaust port. According to the invention, through serial use of various compression mechanisms, the problems that high pumping speed and high vacuum degree cannot be achieved at the same time and a molecular pump must be additionally provided with a backing pump are solved, a single vacuum pump can be used for replacing a plurality of traditional vacuum pumps, and the cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum pumps, and specifically, to a compound multi-compression mechanism vacuum pump with a high compression ratio and a large pumping speed. Background Art

[0002] As a key basic equipment in the industrial and scientific research fields, the performance core of a vacuum pump lies in balancing a large pumping speed and a high compression ratio. In the prior art, due to the differences in their characteristics, turbine compression, traction wheel compression, and scroll compression structures are often applied to compound pumps in the form of pairwise combinations, but there are still significant limitations. The compound pumps in the prior art have the following technical problems: 1. Turbine-traction wheel compound pump; This type of compound pump has a turbine stage and a traction wheel stage in series, such as in the design of some molecular pumps. The turbine stage realizes gas compression through a hierarchical design of moving blades and stationary blades, and the traction wheel stage further increases the compression ratio through momentum transfer. However, the overall compression ratio of the turbine-traction wheel compound pump is still insufficient, and it cannot directly exhaust to the atmospheric environment. It needs to rely on a pre-stage mechanical pump / dry pump to pre-pump the vacuum. This defect limits its application scenarios. Especially in working conditions that require rapid start-stop or frequent exposure to the atmosphere, an additional pre-stage pump group needs to be configured, increasing the system complexity and cost.

[0003] 2. Traction wheel-scroll compound pump; This type of compound pump combines a traction wheel stage and a scroll stage, and uses the high compression ratio characteristic of scroll compression to achieve direct atmospheric exhaust. However, due to the natural defects of the traction wheel, its pumping speed and compression ratio are much lower than those of the turbine stage; and the scroll stage relies on the principle of volume compression, and the gas processing capacity drops sharply as the pressure increases. After the two are connected in series, the overall pumping speed and compression ratio are insufficient, making it difficult to meet the rapid pumping requirements of a large-volume cavity, and the vacuum degree is not ideal.

[0004] Therefore, there is an urgent need in the art for a vacuum pump that can directly exhaust to the atmosphere and has both a large pumping speed and a high compression ratio. Summary of the Invention

[0005] Aiming at the defects in the prior art, the purpose of the present invention is to provide a compound multi-compression mechanism vacuum pump with a high compression ratio and a large pumping speed.

[0006] The compound multi-compression mechanism vacuum pump with a high compression ratio and a large pumping speed according to the present invention includes a base, a motor, a rotor, a housing, and a main shaft; The base is fixedly installed inside the housing, the rotor is rotatably sleeved outside the base, the main shaft is rotatably installed inside the base and is coaxially connected to the rotor, and the motor is fixedly installed inside the base for driving the main shaft to rotate; The rotor includes a rotor body, a main shaft, a turbine structure, a traction wheel, and a scroll blade row. The turbine structure is disposed at the intake end of the rotor body and forms a turbine compression structure with the stationary blades inside the pump body. The traction wheel and the scroll blade row are sequentially arranged on the rotor body until the outlet end; A scroll compression structure is formed between the scroll blade row and the scroll guide groove of the casing. The traction wheel compression structure includes a first-stage traction wheel located on the outside and a second-stage traction wheel located on the inside. A first-stage exhaust port and a second-stage exhaust port are provided on the base; The gas path outlet of the turbine compression structure is communicated with the gas path inlet of the first-stage traction wheel. The gas path outlet of the first-stage traction wheel is simultaneously communicated with the first-stage exhaust port and the gas path inlet of the second-stage traction wheel. The gas path outlet of the second-stage traction wheel is communicated with the gas path inlet of the scroll compression structure. The gas path outlet of the scroll compression structure is communicated with the second-stage exhaust port; A valve is installed on the first-stage exhaust port. During the first air extraction stage, the valve is opened, and most of the gas sequentially passes through the turbine compression structure and the first-stage traction wheel and is discharged from the first-stage exhaust port. A small part of the gas sequentially passes through the turbine compression structure, the first-stage traction wheel, the second-stage traction wheel, and the scroll compression structure and is discharged from the second-stage exhaust port; During the second air extraction stage, the valve is closed, and the remaining gas sequentially passes through the turbine compression structure, the first-stage traction wheel, the second-stage traction wheel, and the scroll compression structure and is discharged from the second-stage exhaust port.

[0007] Preferably, the turbine structure includes a plurality of turbine blades arranged in a stacked manner. A plurality of stationary blades arranged in a stacked manner are fixedly installed inside the base through a retaining ring. The stationary blades and the turbine blades are alternately installed in sequence to form a turbine compression structure.

[0008] Preferably, a vertical cylindrical partition is provided in the middle of the traction wheel compression structure. A first spiral structure is provided outside the vertical cylindrical partition to form a first-stage traction wheel. A second spiral structure is provided inside the vertical cylindrical partition to form a second-stage traction wheel; The first-stage traction wheel is used to guide gas molecules from the gas path inlet of the first-stage traction wheel to the gas path outlet in the first direction by rotation. The second-stage traction wheel is used to guide gas molecules from the gas path inlet of the second-stage traction wheel to the gas path outlet in the second direction opposite to the first direction by rotation.

[0009] Preferably, the gas path inlet of the first-stage traction wheel is directly communicated with the turbine compression structure; The gas path outlet of the first-stage traction wheel is communicated with the gas path inlet of the second-stage traction wheel through the gap between the vertical cylindrical partition and the base.

[0010] Preferably, a radial magnetic levitation unit is fixedly installed inside the base, and the radial magnetic levitation unit is sleeved outside the main shaft.

[0011] Preferably, the rotor includes a first rotor and a second rotor, and the first rotor and the second rotor are installed in pairs at both ends of the main shaft; The mechanical rotation directions of the turbine structure, the traction wheel, and the scroll blade row of the first rotor are opposite to those of the turbine structure, the traction wheel, and the scroll blade row of the second rotor.

[0012] Preferably, the first rotor and the second rotor are installed face to face; The air outlet ends of the rotor bodies of the first rotor and the second rotor are arranged opposite to each other, and the air inlet ends of the rotor bodies are arranged back to back and respectively face both ends of the base. Openings are provided at both ends of the base and serve as the air inlets of the first turbine structure in the first rotor and the second turbine structure in the second rotor respectively; A first traction wheel and a second traction wheel are arranged at the top of the first rotor. The first traction wheel and the second traction wheel serve as the primary traction wheel and the secondary traction wheel respectively. A second scroll blade row is arranged at the top of the first rotor and is used to form a first scroll compression structure with the scroll guide groove of the base; A third traction wheel and a fourth traction wheel are arranged at the bottom of the second rotor. The third traction wheel and the fourth traction wheel serve as the secondary traction wheel and the primary traction wheel respectively. A first scroll blade row is arranged at the bottom of the second rotor and is used to form a second scroll compression structure with the scroll guide groove of the base; A first exhaust port, a second exhaust port, and a third exhaust port are arranged in the middle of the base. The first exhaust port serves as the secondary exhaust port and is respectively communicated with the gas path outlets of the first scroll compression structure and the second scroll compression structure; A first valve and a second valve are respectively arranged on the second exhaust port and the third exhaust port. The second exhaust port and the third exhaust port serve as the primary exhaust ports and are respectively communicated with the gas path outlets of the first traction wheel and the fourth traction wheel.

[0013] Preferably, the first rotor and the second rotor are installed back to back; The air outlet ends of the rotor bodies of the first rotor and the second rotor are arranged back to back, and the air inlet ends of the rotor bodies are arranged opposite to each other and respectively face the middle of the base. An air inlet is arranged in the middle of the base and serves as the air inlets of the first turbine structure in the first rotor and the second turbine structure in the second rotor respectively; A first traction wheel and a second traction wheel are arranged at the bottom of the first rotor. The first traction wheel and the second traction wheel serve as the primary traction wheel and the secondary traction wheel respectively. A second scroll blade row is arranged at the bottom of the first rotor and is used to form a first scroll compression structure with the scroll guide groove of the base; A third traction wheel and a fourth traction wheel are arranged at the top of the second rotor. The third traction wheel and the fourth traction wheel serve as a secondary traction wheel and a primary traction wheel respectively. A first scroll blade row is arranged at the top of the second rotor and is used to form a second scroll compression structure with the scroll guide groove on the base. Primary exhaust ports and secondary exhaust ports are arranged at both ends of the base. The secondary exhaust ports at both ends are respectively communicated with the gas path outlets of the first scroll compression structure and the second scroll compression structure. Valves are arranged on the primary exhaust ports at both ends and are respectively communicated with the gas path outlets of the first traction wheel and the fourth traction wheel.

[0014] Preferably, a thrust disc, an axial magnetic levitation unit and an axial sensor are coaxially installed in sequence at one end of the main shaft. The axial magnetic levitation unit is connected to the end of the main shaft through the thrust disc. The thrust disc, the axial magnetic levitation unit and the axial sensor form an axial magnetic levitation bearing.

[0015] Preferably, a first protective bearing and a second protective bearing are sleeved outside the main shaft. The first protective bearing is arranged between the main shaft and the base, and the second protective bearing is arranged between the main shaft and the axial magnetic levitation unit.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By using the series connection of a turbine compression structure, a traction wheel compression structure and a scroll compression structure and timely controlling the valve action of the primary exhaust port, the present invention can achieve a high compression ratio while realizing a large pumping speed, solves the problem that a large pumping speed and a high vacuum degree of a vacuum pump cannot be achieved at the same time, and a molecular pump must be equipped with another set of fore pumps. A single vacuum pump can replace several sets of traditional vacuum pumps, greatly reducing the production and manufacturing costs and the use costs.

[0017] 2. By arranging the opening and closing actions of the valves at the primary exhaust ports, the air extraction process is divided into two stages. In the first stage, most of the gas is discharged through the primary exhaust ports, and the air pressure can be quickly reduced to the kilopascal level or even the hectopascal level. In the second stage, through the closing action of the valves, the remaining gas in the vacuum chamber is forced to be discharged through the secondary exhaust ports, so as to achieve a high vacuum degree or even an ultra-high vacuum degree.

[0018] 3. By using the series connection of a turbine compression structure, a traction wheel compression structure and a scroll compression structure, the pumping speed in the low vacuum stage can reach up to tens of thousands of cubic meters per hour at most, and the pumping speed in the high vacuum stage can reach up to tens of thousands of liters per second at most, or even higher. The ultimate vacuum can be directly evacuated from the atmosphere to 10 －6 Pa~10 －7 Pa. Description of the Drawings

[0019] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 Schematic diagram of the overall structure of Embodiment 1 in the present invention; Figure 2 is Figure 1 Partial enlarged schematic diagram of part A in Figure 3 Schematic diagram of the overall structure of Embodiment 2 in the present invention; Figure 4 is Figure 3 Partial enlarged schematic diagram of part A in

[0020] The figure shows: Specific embodiments

[0021] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all fall within the protection scope of the present invention.

[0022] The present invention discloses a compound multi-compression mechanism vacuum pump with a high compression ratio and a large pumping speed. By means of the series operation of turbine compression, traction wheel compression, and scroll blade pair compression and the timely control of the action of the exhaust port valve, the vacuum pump achieves excellent performance with both a large pumping speed and a high compression ratio. The pumping speed in the low vacuum stage can reach up to tens of thousands of cubic meters per hour at most, and the pumping speed in the high vacuum stage can reach up to tens of thousands of liters per second at most, or even higher; the ultimate vacuum can be directly evacuated from the atmosphere to 10 －5 Pa to 10 －6 Pa, and can even reach a higher ultimate vacuum, such as 10 －6 Pa to 10 －7 Pa, which can meet the needs of most industrial production and experimental equipment, thus avoiding the complexity of the series combination system of a molecular pump and a fore pump. It is not only more efficient, but also can significantly reduce costs. In short, the goal of being able to pump from the atmospheric state to a high vacuum degree or even an ultra-high vacuum using only one vacuum pump has incomparable advantages in terms of cost savings, mechanism simplification, and reduction of the full life cycle usage cost.

[0023] According to the compound multi-compression mechanism vacuum pump with a high compression ratio and a large pumping speed provided by the present invention, it includes a base, a motor 37, a rotor, a radial magnetic levitation unit, and a main shaft 10; the radial magnetic levitation unit 40 and the motor 37 are fixedly installed inside the base, the rotor is rotatably sleeved outside the radial magnetic levitation unit 40 and the motor 37, the main shaft 10 is rotatably installed inside the radial magnetic levitation unit 40 and the motor 37, and is coaxially connected to the rotor. The motor 37 is fixedly installed inside the base and is used to drive the main shaft 10 to rotate; The rotor includes a rotor body, a turbine structure, a traction wheel, and a scroll blade row. The turbine structure is arranged at the air inlet end of the rotor body and forms a turbine compression structure with the stationary vanes at all levels inside the base. The traction wheel and the scroll blade row are sequentially arranged at the air outlet end of the rotor body from outside to inside; A scroll compression structure is formed between the scroll blade row and the scroll guide groove of the base. The traction wheel compression structure includes a first-stage traction wheel located on the outside and a second-stage traction wheel located on the inside. A first-stage exhaust port and a second-stage exhaust port are arranged on the base; the gas path outlet of the turbine compression structure is communicated with the gas path inlet of the first-stage traction wheel, the gas path outlet of the first-stage traction wheel is simultaneously communicated with the first-stage exhaust port and the gas path inlet of the second-stage traction wheel, the gas path outlet of the second-stage traction wheel is communicated with the gas path inlet of the scroll compression structure, and the gas path outlet of the scroll compression structure is communicated with the second-stage exhaust port; A valve is installed on the first-stage exhaust port. When in the first air extraction stage, the valve is opened, and most of the gas sequentially passes through the turbine compression structure and the first-stage traction wheel and is discharged from the first-stage exhaust port; a small part of the gas sequentially passes through the turbine compression structure, the first-stage traction wheel, the second-stage traction wheel, and the scroll compression structure and is discharged from the second-stage exhaust port; when in the second air extraction stage, the valve is closed, and the remaining gas in the vacuum chamber sequentially passes through the turbine compression structure, the first-stage traction wheel, the second-stage traction wheel, and the scroll compression structure and is discharged from the second-stage exhaust port.

[0024] Specifically, the turbine structure includes a plurality of turbine blades arranged in a stacked manner. Inside the base, a plurality of stator blades arranged in a stacked manner are fixedly installed through a retaining ring. The stator blades and the turbine blades are alternately installed in sequence to form a turbine compression structure. A vertical cylindrical partition is provided in the middle of the traction wheel compression structure. A first spiral structure is provided outside the vertical cylindrical partition to form a primary traction wheel, and a second spiral structure is provided inside the vertical cylindrical partition to form a secondary traction wheel. The primary traction wheel is used to guide gas molecules from the gas path inlet of the primary traction wheel to the gas path outlet in the first direction by rotation. The secondary traction wheel is used to guide gas molecules from the gas path inlet of the secondary traction wheel to the gas path outlet in the second direction opposite to the first direction by rotation. The gas path inlet of the primary traction wheel is directly communicated with the turbine compression structure. That is to say, after the gas passes through the turbine compression structure, it directly enters the primary traction wheel. The gas path outlet of the primary traction wheel is communicated with the gas path inlet of the secondary traction wheel through the gap between the vertical cylindrical partition and the base. A radial magnetic levitation unit 40 and a motor stator 37 are fixedly installed inside the base, and the radial magnetic levitation unit 40 and the motor stator 37 are sleeved outside the main shaft 10.

[0025] The above is the basic embodiment of the present invention, and its working principle is as follows: Taking Figure 1 the rotor in the upper middle part as an example, the gas to be pumped is first compressed layer by layer in the second turbine structure 42. Among them, the second turbine structure 42 can be designed with compression levels according to needs. Then it enters the fourth traction wheel 39 for further compression. After being compressed by the fourth traction wheel 39, most of it is directly discharged through the third exhaust port 36, and a small part enters the third traction wheel 38 for compression through the gap between the second rotor 9 and the base. The compressed gas is sent to the first scroll blade row 8 for the fourth stage of compression, and finally discharged outside the pump through the first exhaust port 11. There is a key point that has been ignored in the art, and it is also a technical problem that has not been broken through. If the vacuum pump is directly started to pump air under a relatively high pressure environment, the problem of holding air is likely to occur due to the mismatch between the vortex compression structure and the turbine compression structure, which will greatly affect the work efficiency. The second valve 35 provided at the third exhaust port 36 of the present invention, in the initial stage of pumping, when the gas passes through the compression of the second turbine structure 42 and the fourth traction wheel 39, the cavity pressure drops to a certain level - such as the kilopascal level or even the hectopascal level - the compression ratio reaches the limit of the second turbine structure 42 and the fourth traction wheel 39, and the cavity pressure no longer drops or drops slowly, and the second valve 35 can be closed to force the gas to be discharged from the pump body along the path of "second turbine structure 42 → fourth traction wheel 39 → third traction wheel 38 → first vortex blade row pair → first exhaust port 11". In this way, under the premise that most of the gas is discharged from the vacuum cavity, the amount of remaining gas at this time is very small. Under the support of the compression ratio of the third traction wheel 38 and the first vortex blade row pair, it can not only be quickly pumped out, but also reach the ideal ultimate vacuum degree.

[0026] For ease of understanding, the present invention can be regarded as dividing the exhaust process into two stages: in the first stage, in this stage, the second valve 35 is open, most of the gas is compressed by the second turbine structure 42 and the fourth traction wheel 39, and discharged from the pump through the third exhaust port 36 and the second valve 35, and a small part is discharged from the pump body through the path of "second turbine structure 42→fourth traction wheel 39→third traction wheel 38→first vortex blade row pair→first exhaust port 11". The exhaust speed in the first stage is very high, and the pressure can be quickly reduced to the kilopascal level or even the hectopascal level; in the second stage, when the pressure of the pumped cavity drops to a certain level, such as the kilopascal level or even the hectopascal level, the second valve 35 is closed, forcing all the remaining gas to be discharged from the pump body through the path of "second turbine structure 42→fourth traction wheel 39→third traction wheel 38→first vortex blade row pair→first exhaust port 11". In this stage, the compression ratio is very large, and the vacuum degree can be drawn to 10 －5 Pa~10 －6 Pa, even better.

[0027] Furthermore, the present invention adopts two mechanical structures: face-to-face design or back-to-back design. Two rotors rotate coaxially, but their mechanical rotation directions are opposite. Please note: Here, the rotation direction refers not to the direction of rotation, but to the machining rotation direction. Assuming the upper rotor is left-handed, the lower rotor must be right-handed, which not only cancels the unidirectional force of the compression effect, but also doubles the pumping speed compared with the same caliber. The difference between the two is that in the face-to-face design, air enters from both ends of the pump body and is discharged through the exhaust port in the central part of the pump body; in the back-to-back design, air enters from the center of the pump body and is discharged from both ends of the pump body. The axial force deviation part is compensated by the axial magnetic bearing composed of the axial sensor 22, the thrust disk 23, and the axial magnetic levitation unit 24; the above two mechanical structures of the face-to-face design and the back-to-back design will be further specifically described through Embodiment 1 and Embodiment 2; Embodiment 1: As Figure 1 , Figure 2 shown, this embodiment discloses a form of vacuum pump with a face-to-face installation. Specifically, the first rotor 13 and the second rotor 9 are paired and installed at both ends of the main shaft 10, and the mechanical rotation directions of the turbine structure, the traction wheel, and the scroll vane row pair of the first rotor 13 are opposite to those of the turbine structure, the traction wheel, and the scroll vane row pair of the second rotor 9.

[0028] The air outlet ends of the rotor bodies of the first rotor 13 and the second rotor 9 are arranged opposite to each other, and the air inlet ends of the rotor bodies are arranged back to back and respectively face both ends of the base. Openings are provided at both ends of the base, which are respectively used as the air path inlets of the first turbine structure 25 in the first rotor 13 and the second turbine structure 42 in the second rotor 9; A first traction wheel 31 and a second traction wheel 32 are arranged at the top of the first rotor 13. The first traction wheel 31 and the second traction wheel 32 are respectively used as the primary traction wheel and the secondary traction wheel. A second scroll vane row 12 is arranged at the top of the first rotor 13, which is the first scroll compression structure; a third traction wheel 38 and a fourth traction wheel 39 are arranged at the bottom of the second rotor 9. The third traction wheel 38 and the fourth traction wheel 39 are respectively used as the secondary traction wheel and the primary traction wheel. A first scroll vane row 8 is arranged at the bottom of the second rotor 9, which is the second scroll compression structure; A first exhaust port 11, a second exhaust port 33, and a third exhaust port 36 are arranged in the middle of the base. The first exhaust port 11 is used as the secondary exhaust port and is respectively communicated with the air path outlets of the first scroll compression structure and the second scroll compression structure; first valves 34 and second valves 35 are respectively arranged on the second exhaust port 33 and the third exhaust port 36. The second exhaust port 33 and the third exhaust port 36 are used as the primary exhaust ports and are respectively communicated with the air path outlet of the first traction wheel 31 and the air path outlet of the fourth traction wheel 39.

[0029] Embodiment 2: AsFigure 1 , Figure 2 As shown, this embodiment discloses a vacuum pump type that is installed back-to-back. Specifically, the first rotor 13 and the second rotor 9 are installed in pairs at both ends of the main shaft 10, and the turbine structure, traction wheel and vortex blade row pair of the first rotor 13 have a mechanical rotation direction opposite to that of the turbine structure, traction wheel and vortex blade row pair of the second rotor 9.

[0030] The air outlet ends of the rotor bodies of the first rotor 13 and the second rotor 9 are arranged in opposite directions, and the air inlet ends of the rotor bodies are arranged opposite to each other and face the middle of the base respectively. The middle of the base is provided with an air inlet 43, which serves as the air path inlet of the first turbine structure 25 in the first rotor 13 and the second turbine structure 42 in the second rotor 9 respectively. A first traction wheel 31 and a second traction wheel 32 are provided at the bottom of the first rotor 13, and the first traction wheel 31 and the second traction wheel 32 serve as a primary traction wheel and a secondary traction wheel respectively. A second vortex blade row 12 is provided at the bottom of the first rotor 13, which is a first vortex compression structure; a third traction wheel 38 and a fourth traction wheel 39 are provided at the top of the second rotor 9, and the third traction wheel 38 and the fourth traction wheel 39 serve as a secondary traction wheel and a primary traction wheel respectively. A first vortex blade row 8 is provided at the top of the second rotor 9, which is a second vortex compression structure; Both ends of the pump body are provided with a primary exhaust port and a secondary exhaust port. The secondary exhaust port first exhaust port 11 at both ends is respectively connected to the air path outlets of the first scroll compression structure and the second scroll compression structure. The primary exhaust port second exhaust port 33 and the third exhaust port 36 at both ends are respectively provided with a first valve 34 and a second valve 35, and are respectively connected to the air path outlets of the first traction wheel 31 and the fourth traction wheel 39.

[0031] Through the above designs of Example 1 and Example 2, the axial force of the compression effect can be effectively offset, and the pumping speed is doubled compared with the same caliber; In a preferred embodiment, in order to compensate for part of the axial force that cannot be offset by the two rotors and to achieve dynamic control, a thrust plate 23, an axial magnetic suspension unit 24 and an axial sensor 22 are coaxially installed in sequence at one end of the main shaft 10; the axial magnetic suspension unit 24 is connected to the end of the main shaft 10 through the thrust plate 23, and the thrust plate 23, the axial magnetic suspension unit 24 and the axial sensor 22 form an axial magnetic suspension bearing.

[0032] The main shaft 10 is externally sleeved with a first protective bearing 21 and a second protective bearing 41 ; the first protective bearing 21 is disposed between the main shaft 10 and the base, and the second protective bearing 41 is disposed between the main shaft 10 and the axial magnetic suspension unit 24 .

[0033] It should be noted that although the magnetic levitation bearing is adopted in this embodiment, the magnetic levitation bearing is not the main inventive point of the design. It is only the bearing mechanism and the axial force compensation mechanism of the rotor system. Therefore, not too much description will be made on the magnetic levitation bearing mechanism. However, it should be emphasized that since the magnetic levitation bearing is adopted in the present invention, 360-degree omnidirectional installation can be achieved, and installation methods such as upright, inverted, and horizontal are all within the scope covered by the present invention.

[0034] Furthermore, the present invention can be flexibly modified according to the actual needs of the user, that is, the user's own requirements for pumping speed and vacuum degree, for the number of stages of turbine compression from one to a dozen, the length of the traction wheel compression, the number of spiral heads and the spiral angle, and the number of turns of the scroll blade row pair from one to a dozen to meet the actual needs. It is even possible to cancel a certain structure, such as canceling the traction wheel and only leaving the turbine and the scroll blade row pair; or canceling the turbine and only leaving the traction wheel and the scroll blade row pair; or canceling the scroll blade row pair and only leaving the turbine and the traction wheel.

[0035] It is even possible in a relatively smaller model, such as when the turbine diameter ≤ 350 mm, that the design of double-rotor symmetry cancellation is not required. Only one rotor is needed, and the axial magnetic levitation bearing is designed to be larger to generate sufficient axial magnetic force to stabilize the rotor. Therefore, whether a double-rotor design or a single-rotor design is adopted, it should not be construed as a limitation to this application.

[0036] Adopt a face-to-face or back-to-back installation method. Such a design can cancel most of the axial forces generated during the compression process. It should be noted that whether it is face-to-face or back-to-back, there is no essential difference in the compression process and the gas path direction between the two, which is determined by the actual needs; Embodiment 3: This embodiment mainly makes a specific description of the number of stages of turbine compression. For example, Figure 1 or Figure 3 As shown, a first stator 1, a second stator 2, a third stator 3, a fourth stator 4, a fifth stator 5, a sixth stator 6, and a seventh stator 7 are successively installed on the outer ring of the second turbine structure 42, and the above-mentioned stators are fixed inside the base through the first retaining ring 26, the second retaining ring 27, the third retaining ring 28, the fourth retaining ring 29, and the fifth retaining ring 30 located in the gap; an eighth stator 14, a ninth stator 15, a tenth stator 16, an eleventh stator 17, a twelfth stator 18, a thirteenth stator 19, and a fourteenth stator 20 are successively installed on the outer ring of the first turbine structure 25, and the above-mentioned stators are fixed inside the base through the first retaining ring 26, the second retaining ring 27, the third retaining ring 28, the fourth retaining ring 29, and the fifth retaining ring 30 located in the gap. Through the cooperation of the above-mentioned stators and the turbine structure of the rotor, a multi-stage turbine compression structure is formed. It should be noted that the number of stages of turbine compression is not fixed and is also set according to actual needs.

[0037] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0038] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed, characterized in that: It includes a base, a motor (37), a rotor, a casing and a main shaft (10); The base is fixedly mounted inside the casing, the rotor is rotatably mounted outside the base, the main shaft (10) is rotatably mounted inside the base and is coaxially connected to the rotor, and the motor (37) is fixedly mounted inside the base and is used to drive the main shaft (10) to rotate; The rotor comprises a rotor body, a turbine structure, a traction wheel and a vortex blade row, wherein the turbine structure is arranged on the air inlet end of the rotor body and forms a turbine compression structure with the inside of the base, and the traction wheel and the vortex blade row are arranged on the air outlet end of the rotor body in sequence from the outside to the inside; A vortex compression structure is formed between the vortex blade row and the vortex guide groove of the casing, the traction wheel includes a primary traction wheel located on the outside and a secondary traction wheel located on the inside, and a primary exhaust port and a secondary exhaust port are provided on the base; The gas path outlet of the turbine compression structure is connected to the gas path inlet of the first-stage traction wheel, the gas path outlet of the first-stage traction wheel is connected to the first-stage exhaust port and the gas path inlet of the second-stage traction wheel at the same time, the gas path outlet of the second-stage traction wheel is connected to the gas path inlet of the vortex compression structure, and the gas path outlet of the vortex compression structure is connected to the second-stage exhaust port; A valve is installed on the first-stage exhaust port. When in the first exhaust stage, the valve is opened, and most of the gas passes through the turbine compression structure and the first-stage traction wheel in sequence and is discharged from the first-stage exhaust port, and a small part of the gas passes through the turbine compression structure, the first-stage traction wheel, the second-stage traction wheel and the vortex compression structure in sequence and is discharged from the second-stage exhaust port; In the second exhaust stage, the valve is closed, and the remaining gas passes through the turbine compression structure, the first-stage traction wheel, the second-stage traction wheel and the vortex compression structure in sequence, and is discharged from the second-stage exhaust port.

2. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 1 is characterized in that: The turbine structure comprises a plurality of stacked turbine blades, a plurality of stacked stators are fixedly mounted inside the base via a pressure ring, and the stators and turbine blades are alternately mounted in sequence to form a turbine compression structure.

3. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 1 is characterized in that: A vertical cylindrical partition is provided in the middle of the traction wheel, a first spiral structure is provided on the outer side of the vertical cylindrical partition to form a primary traction wheel, and a second spiral structure is provided on the inner side of the vertical cylindrical partition to form a secondary traction wheel; The primary traction wheel is used to guide the gas molecules from the gas path inlet to the gas path outlet of the primary traction wheel along a first direction by rotating, and the secondary traction wheel is used to guide the gas molecules from the gas path inlet to the gas path outlet of the secondary traction wheel along a second direction opposite to the first direction by rotating.

4. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 3 is characterized in that: The gas path inlet of the first-stage traction wheel is directly connected to the turbine compression structure; The air path outlet of the first-stage traction wheel is communicated with the air path inlet of the second-stage traction wheel through the gap between the vertical cylindrical partition and the base.

5. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 1, characterized in that: A radial magnetic suspension unit (40) is fixedly mounted inside the base, and the radial magnetic suspension unit (40) is sleeved outside the main shaft (10).

6. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 1, characterized in that: The rotor comprises a first rotor (13) and a second rotor (9), wherein the first rotor (13) and the second rotor (9) are mounted in pairs at two ends of a main shaft (10); The turbine structure, traction wheel and vortex blade row of the first rotor (13) have mechanical rotation directions opposite to those of the turbine structure, traction wheel and vortex blade row of the second rotor (9).

7. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 6, characterized in that: The first rotor (13) and the second rotor (9) are installed face to face; The air outlet ends of the rotor bodies of the first rotor (13) and the second rotor (9) are arranged opposite to each other, and the air inlet ends of the rotor bodies are arranged opposite to each other and respectively face the two ends of the base, and the two ends of the base are provided with openings, which respectively serve as air inlets for the first turbine structure (25) in the first rotor (13) and the second turbine structure (42) in the second rotor (9); A first traction wheel (31) and a second traction wheel (32) are arranged on the top of the first rotor (13), the first traction wheel (31) and the second traction wheel (32) serving as a primary traction wheel and a secondary traction wheel respectively, and a second vortex blade row (12) is arranged on the top of the first rotor (13) for forming a first vortex compression structure with the vortex guide groove of the base; A third traction wheel (38) and a fourth traction wheel (39) are provided at the bottom of the second rotor (9), the third traction wheel (38) and the fourth traction wheel (39) serving as a secondary traction wheel and a primary traction wheel respectively, and a first vortex blade row (8) is provided at the bottom of the second rotor (9) for forming a second vortex compression structure with the vortex guide groove of the base; A first exhaust port (11), a second exhaust port (33) and a third exhaust port (36) are provided in the middle of the base, wherein the first exhaust port (11) serves as a secondary exhaust port and is respectively connected to the gas path outlets of the first scroll compression structure and the second scroll compression structure; The second exhaust port (33) and the third exhaust port (36) are provided with a first valve (34) and a second valve (35), respectively. The second exhaust port (33) and the third exhaust port (36) serve as primary exhaust ports and are connected to the gas outlet of the first traction wheel (31) and the gas outlet of the fourth traction wheel (39), respectively.

8. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 6, characterized in that: The first rotor (13) and the second rotor (9) are installed back to back; The air outlet ends of the rotor bodies of the first rotor (13) and the second rotor (9) are arranged in opposite directions, and the air inlet ends of the rotor bodies are arranged opposite to each other and face the middle of the base respectively; the middle of the base is provided with an air inlet (43), which serves as the air inlet of the first turbine structure (25) in the first rotor (13) and the second turbine structure (42) in the second rotor (9); A first traction wheel (31) and a second traction wheel (32) are provided at the bottom of the first rotor (13), the first traction wheel (31) and the second traction wheel (32) serving as a primary traction wheel and a secondary traction wheel respectively, and a second vortex blade row (12) is provided at the bottom of the first rotor (13) for forming a first vortex compression structure with the vortex guide groove of the base; A third traction wheel (38) and a fourth traction wheel (39) are arranged on the top of the second rotor (9), the third traction wheel (38) and the fourth traction wheel (39) serving as a secondary traction wheel and a primary traction wheel respectively, and a first vortex blade row (8) is arranged on the top of the second rotor (9) for forming a second vortex compression structure with the vortex guide groove of the base; Both ends of the base are provided with a primary exhaust port and a secondary exhaust port, the secondary exhaust ports at both ends are respectively connected to the gas outlets of the first scroll compression structure and the second scroll compression structure, and the primary exhaust ports at both ends are provided with valves, and are respectively connected to the gas outlets of the first traction wheel (31) and the gas outlets of the fourth traction wheel (39).

9. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 1, characterized in that: A thrust plate (23), an axial magnetic suspension unit (24) and an axial sensor (22) are coaxially mounted in sequence on one end of the main shaft (10); The axial magnetic suspension unit (24) is connected to the end of the main shaft (10) via a thrust plate (23); the thrust plate (23), the axial magnetic suspension unit (24) and the axial sensor (22) form an axial magnetic suspension bearing.

10. The compound multi-compression mechanism vacuum pump with high compression ratio and high pumping speed according to claim 8, characterized in that: The main shaft (10) is externally sleeved with a first protective bearing (21) and a second protective bearing (41); The first protection bearing (21) is arranged between the main shaft (10) and the base, and the second protection bearing (41) is arranged between the main shaft (10) and the axial magnetic suspension unit (24).

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