Magnetically-driven two-stage water ring vacuum pump

Abstract

The invention provides a magnetically-driven two-stage water ring vacuum pump. The magnetically-driven two-stage water ring vacuum pump comprises a pump shell, a switching body and a magnetically-driven assembly, the pump shell is divided into two pump chambers through an adapter body, a rotatable rotor is eccentrically installed in each pump chamber, each rotor is provided with a plurality of rotor blades, and media conveyed from an inlet to an outlet of the pump chamber are compressed through rotation of the rotor blades. A magnetic unit is mounted in the rotor; a gas flow channel and a service liquid flow channel are arranged between the switching body and the two pump chambers, and the gas flow channel is used for inputting corrosive gas into the pump chambers for treatment and outputting the treated gas; the service liquid flow channel is used for conveying service liquid for treating corrosive gas into the pump chamber and outputting corrosion products; the magnetic driving assembly drives the rotor to rotate through a magnetic field. The water ring vacuum pump can effectively solve the problems of leakage, low pumping efficiency, component abrasion, remarkable reduction of residual pressure of gas and the like of the water ring vacuum pump.

Description

Technical Field

[0001] The invention relates to the field of water ring vacuum pumps, and in particular to a magnetically driven two-stage water ring vacuum pump. Background Art

[0002] Water ring vacuum pumps are used to pump a variety of gases, but their typical structural materials (such as stainless steel, cast iron, brass, etc.) make them unsuitable for long-term use with highly corrosive or reactive gases (i.e., acidic, alkaline, oxidizing, or reducing gases). Known water ring vacuum pumps are made of exotic materials such as titanium, ceramics, and polymers. However, these materials are not only expensive but also difficult to manufacture with the required precise dimensional tolerances, especially the tolerances between certain components, such as the rotor and stator.

[0003] During the vacuum pumping process of some semiconductor manufacturing processes, such as plasma etching, the exhaust gas generated chemically reacts or dissolves with the service liquid (usually water) in the water ring vacuum pump. This produces a corrosive working liquid, which then reacts with the internal components of the pump to produce corrosion products. These corrosion products may cause further corrosion and wear within the pump system. Single-stage water ring vacuum pumps have limited ultimate vacuum, and in some low-pressure areas close to the ultimate vacuum, the pumping rate will drop significantly, resulting in insufficient performance. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a magnetically driven two-stage water ring vacuum pump, which can effectively solve the problems of leakage, low pumping efficiency, component wear, and significantly reduce the residual pressure of the gas in the water ring vacuum pump, and has the characteristics of greater stability and energy saving.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] A magnetically driven two-stage water ring vacuum pump comprises a pump housing, an adapter, and a magnetic drive assembly. The pump housing is divided into two pump chambers by the adapter, wherein a rotatable rotor is eccentrically mounted in each pump chamber, the rotor having a plurality of rotor blades. The rotor blades rotate to compress a medium transported from an inlet to an outlet of the pump chamber. A magnetic unit is mounted within the rotor.

[0007] A gas flow channel and a service liquid flow channel are provided between the adapter and the two pump chambers. The gas flow channel is used to input corrosive gas into the pump chamber for treatment and output the treated gas; the service liquid flow channel is used to transport the service liquid for treating corrosive gas into the pump chamber and output corrosion products; the magnetic drive assembly drives the rotor to rotate through a magnetic field.

[0008] Furthermore, a pivot is installed in the pump housing, and the pivot passes through the adapter and two pump chambers; the rotor is supported on the pivot; and the pivot eccentrically passes through the pump chamber.

[0009] Furthermore, the adapter body is respectively provided with a gas inlet, a gas outlet, a water inlet and a drain port, the gas inlet and the water inlet are respectively connected to a pump chamber, the gas outlet and the water outlet are respectively connected to another pump chamber, and the adapter body is provided with a fluid channel connecting the two pump chambers, the gas inlet, a pump chamber, the fluid channel, another pump chamber and the gas outlet constitute a gas flow channel; the water inlet, a pump chamber, the fluid channel, another pump chamber and the drain port constitute a service liquid flow channel.

[0010] Furthermore, the magnetic drive assembly includes a driven permanent magnet and a stator winding. The driven permanent magnet is driven by the stator winding. The driven permanent magnet is located inside the rotor. The stator winding is located inside the pump casing. An isolation sleeve is installed between the stator winding and the driven permanent magnet.

[0011] Furthermore, the rotor has a hub for mounting a support body at its center, and a groove is provided between the hub and the edge of the rotor; the hub is mounted on the pivot through the support body; blades are mounted in the groove on the outside of the hub; distribution plates are respectively mounted on both sides of the adapter, and one side of the distribution plate has a protrusion extending axially into the groove of the rotor, and an eccentric hole in the protrusion is sleeved on the outside of the blade; the eccentric hole and the wall of the groove form a pump chamber.

[0012] Furthermore, the service fluid entering the pump is transported between the pivot and the rotor for lubricating and flushing the outer surface of the pivot; an axially or / and radially extending channel is provided between the pivot and the rotor for transporting the service fluid to the pivot.

[0013] Furthermore, at least one pair of repulsive anti-touch magnets is installed inside one end of the rotor and inside the distribution plate.

[0014] Furthermore, both ends of the pivot are mounted in the pump housing via thrust plates; the rotor includes a bearing surface for cooperating with the thrust plate, and the service fluid entering the pump is guided between the bearing surface and the thrust plate to form a non-contact fluid dynamic axial bearing.

[0015] The beneficial effects of the present invention are:

[0016] 1. The magnetically driven two-stage water ring vacuum pump of the present invention transmits torque to the rotor in the pump chamber through magnetic drive. This arrangement avoids the need for a rotating shaft seal and significantly reduces the risk of leakage.

[0017] 2. The magnetically driven two-stage water ring vacuum pump described in the present invention has a gas flow channel and a service liquid flow channel provided between the adapter and the two pump chambers, allowing the service liquid to flow in each pump cavity. The gas flow channel is used to input corrosive gas into the pump chamber for treatment and output the treated gas; the service liquid flow channel is used to transport the service liquid for treating the corrosive gas into the pump chamber and output corrosion products, thereby preventing corrosion and wear caused by the corrosion products in the pump system.

[0018] 3. The magnetically driven two-stage water ring vacuum pump of the present invention is mounted vertically, with the shaft typically extending vertically. Vertical mounting allows the pump inlet to be parallel to the axis, allowing the particle-laden gas flow from the process chamber to enter the pump chamber unimpeded, thereby minimizing the possibility of blockage. Vertical mounting also significantly reduces the footprint. The use of an exhaust port perpendicular to the axis (horizontal to the ground) allows for very close coupling of the gas / liquid separator tank, further improving pumping packaging and reducing the footprint.

[0019] 4. The magnetically driven two-stage water ring vacuum pump described in the present invention can provide a higher pressure output through a staged pressurization design, and enables the pump to operate at a lower compression ratio, thereby reducing energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a cross-sectional view of the outlet phase of the magnetically driven two-stage water ring vacuum pump described in the present invention.

[0022] Figure 2 This is a cross-sectional view of the inlet phase of the magnetically driven two-stage water ring vacuum pump described in the present invention.

[0023] Figure 3 for Figure 1 BB cross-sectional view.

[0024] Figure 4 for Figure 1 AA cross-sectional view.

[0025] Figure 5 It is a cross-sectional schematic diagram of the distribution plate of the present invention.

[0026] Figure 6 Schematic diagram of the liquid distribution channel according to the present invention.

[0027] In the picture:

[0028] 1- pump housing; 2- pivot; 3- isolation sleeve; 4- rear thrust plate; 5- second bearing; 6- secondary pump chamber; 7- rear distribution plate; 8- adapter; 9- front distribution plate; 10- anti-touch magnet; 11- gas outlet; 12- hub; 13- driven permanent magnet; 14- primary pump chamber; 15- rotor; 16- first bearing; 17- front thrust plate; 18- fluid channel; 19- water inlet; 20- stator winding; 21- gas inlet; 22- drain outlet; 23- inlet hole; 24- outlet hole; 26- protrusion; 27- liquid distribution channel; 28- blade; 29- eccentric hole; 30- radial gap; 31- axial gap. DETAILED DESCRIPTION

[0029] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "axial", "radial", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] like Figure 1 and Figure 2As shown, the magnetically driven two-stage water ring vacuum pump of the present invention includes a pump housing, an adapter body 8, and a magnetic drive assembly. The pump housing is divided into two pump chambers by the adapter body 8, wherein a rotatable rotor is eccentrically mounted in each pump chamber. The rotor has a plurality of blades 28 extending radially from the rotor axis. The rotation of the blades 28 compresses the medium transported from the inlet to the outlet of the pump chamber. A magnetic unit is mounted within the rotor, and the water ring vacuum pump includes a magnetic coupling device for driving the rotor to rotate. As the rotor 15 rotates, the blades 28 come into contact with the liquid and form the liquid into an annular liquid ring within the annular pump chamber.

[0033] A gas flow channel and a service liquid flow channel are provided between the adapter 8 and the two pump chambers. The gas flow channel is used to input corrosive gas into the pump chamber for treatment and output the treated gas; the service liquid flow channel is used to transport the service liquid for treating corrosive gas into the pump chamber and output corrosion products; the magnetic drive component drives the rotor to rotate through the magnetic field.

[0034] Example

[0035] The pump housing 1 is divided into a primary pump chamber 14 and a secondary pump chamber 6 by an adapter 8, a pivot 2 is installed in the pump housing 1, and the pivot 2 passes through the adapter 8, the primary pump chamber 14 and the secondary pump chamber 6; a rotor 15 is provided in the primary pump chamber 14 and the secondary pump chamber 6 respectively, the rotor 15 in the primary pump chamber 14 is mounted on the pivot 2 through a first bearing 16; the rotor 15 in the secondary pump chamber 6 is mounted on the pivot 2 through a second bearing 5; an axial gap 31 is provided between the pivot 2 and the center hole of the adapter 8 through which liquid can flow; a gas inlet 21, a gas outlet 11, The water inlet 19 and the drain outlet 22, the gas inlet 21 and the water inlet 19 are respectively connected to the primary pump chamber 14, the gas outlet 11 and the water outlet 22 are respectively connected to the secondary pump chamber 6, and a fluid channel 18 connecting the primary pump chamber 14 and the secondary pump chamber 6 is provided in the adapter 8, and the gas-liquid mixture enters the secondary chamber 6 directly through the fluid channel 18; the gas inlet 21, the primary pump chamber 14, the fluid channel 18, the secondary pump chamber 6 and the gas outlet 11 constitute a gas flow channel; the water inlet 19, the primary pump chamber 14, the fluid channel 18, the secondary pump chamber 6 and the drain outlet 22 constitute a service liquid flow channel.

[0036] Since the structures inside the primary pump chamber 14 and the secondary pump chamber 6 are similar, the primary pump chamber 14 will be specifically described below. Figure 2 、 Figure 3 and Figure 4As shown, the center of the rotor 15 in the primary pump chamber 14 has a hub 12 for mounting a first bearing 16, and an annular groove is provided between the hub 12 and the edge of the rotor 15; the hub 12 is mounted on the pivot 2 via the first bearing 16; a plurality of blades 28 are provided on the outer side of the hub 12 extending from the hub 12 toward the edge; a front distribution plate 9 is installed on one side of the adapter body 8, and a protrusion 26 is provided on one side of the front distribution plate that extends axially into the groove of the rotor, as shown in FIG. Figure 3 As shown, the eccentric hole 29 in the raised portion is sleeved on the outside of the blade 28; the eccentric hole 29, the front distribution plate 9, and the wall of the groove form an eccentric primary pump chamber 14, that is, the rotor 15 is eccentrically located within the primary pump chamber 14. The magnetic drive assembly includes a driven permanent magnet 13 and a stator winding 20. The driven permanent magnet 13 is driven by the stator winding 20 and is located within the rotor 15; the stator winding 20 is located within the pump housing 1; and an isolation sleeve 3 is installed between the stator winding 20 and the driven permanent magnet 13. The motor (not shown) causes the stator winding 20 to generate a magnetic field and drive the rotor 15 to rotate. This arrangement avoids the need for rotating shaft seals, significantly reducing the risk of leakage. To prevent collisions, at least a pair of repelling anti-touch magnets 10 are installed inside one end of the rotor 15 and inside the front distribution plate 9. The installation direction of the blade 28 on the rotor 15 in the primary pump chamber 14 is relative to the blade 28 on the rotor 15 in the secondary pump chamber 6 (back-to-back arrangement). Specifically, when observed from the fluid inflow direction, the inclination angle direction of the blade 28 in the primary pump chamber 14 is opposite to the inclination angle direction of the blade 28 in the secondary pump chamber 6. This can be compared to the two blades being installed in a mutually opposed manner, so that the fluid flow direction corresponding to the upstream surface (i.e., the surface that the fluid first contacts) of the blade 28 of the primary pump chamber 14 is opposite, and the fluid flow direction of its downstream surface (i.e., the surface that the fluid contacts last) is also correspondingly opposite. Back-to-back arrangement can improve higher pressure output on the one hand, and structural stability is higher on the other hand.

[0037] Service fluid entering the pump is transported between the pivot 2 and the rotor 15 to lubricate and flush the outer surface of the pivot 2. Axially and / or radially extending channels are provided between the pivot 2 and the rotor 15 for transporting service fluid to the pivot 2. Specifically, regarding the primary pump chamber 14, an axial gap 31 for fluid flow is defined between the pivot 2 and the center hole of the adapter body 8. A radial gap 30 is defined between the rotor 15 and the front distribution plate 9. A labyrinthine gap D exists between the first bearing 16, the rotor 15, and the front distribution plate 9. Figure 2As shown, the labyrinth gap D is composed of axial and radial gaps; similarly, a radial gap 30 is provided between the rotor 15 and the rear distribution plate 7 in the secondary pump chamber 6, and a labyrinth gap D is provided between the second bearing 5, the rotor 15 and the rear distribution plate 7. One or more of the above-mentioned axial gaps and radial gaps constitute an axial or / and radial extension channel for conveying service fluid to the pivot 2. The axial or / and radial extension channel ensures that the entire axial and circumferential range of the pivot 2 is lubricated. The channel flows water along the shaft, and through the rotation of the first bearing 5 and the second bearing 16, the service liquid (such as water) flushes the circumferential surface of the shaft, and clean water is used to remove particulate matter downstream of the shaft. After completing the lubrication task, the service liquid is discharged from the rear end of the first bearing 5 and enters the pump chamber through the gap between it and the adapter plate 8.

[0038] like Figure 1 and Figure 5 As shown in the embodiment, both ends of the pivot shaft 2 are respectively installed in the pump housing 1 through the front thrust plate 17 and the rear thrust plate 4; a gap is provided between the front thrust plate 17 and the rotor 15, and the service fluid is guided to the gap to form a non-contact fluid dynamic axial bearing. The non-contact axial bearing can ensure that the axial force generated during the rotation of the rotor 15 is overcome, thereby preventing the axial movement of the rotor 15.

[0039] like Figure 2 As shown, on the gas inlet side of the primary pump chamber 14, the gas in the compression zone between adjacent rotor blades 28 is moving radially outward, away from the rotor axis. On the gas outlet side of the secondary pump chamber 6, the gas is moving radially inward, toward the rotor axis. The exhaust gas stream entering through the gas inlet 21 is drawn into the spaces between adjacent blades 28. The gas is compressed by the blades 28 and discharged through the gas outlet 11, leaving the pump with a processed gas stream consisting primarily of processed gas but also containing some liquid from the liquid ring. The service fluid can become contaminated by corrosion products or particles generated during the processing of the gas stream. Over time, the liquid may become less effective in treating the gas or become excessively corrosive or abrasive. Therefore, it is necessary to drain the fluid from the pump and replenish it with fresh service fluid. The rate of liquid replenishment depends on several factors, such as the reactivity or solubility rate of certain components in the exhaust stream with the service fluid. The fluid exiting the pump can then be treated to remove corrosion products and / or particles before being reused or directly disposed of. The fluid is discharged from the pump through the drain port 22, and fresh service fluid enters the pump through the water inlet 19.

[0040] like Figure 5As shown, the front distribution plate 9 and the rear distribution plate 7 are internally provided with channels and crescent-shaped openings, which have lubrication, pressure balancing, and buffering functions, as well as control of the gas-liquid flow path, optimize compression efficiency, and reduce energy loss. They generally have an outlet hole 24 and an inlet hole 23. The outlet hole 24 is formed by multiple groups of holes and outputs gas from the secondary chamber 6; the inlet hole 23 receives gas entering from the outside and is a crescent-shaped opening. The fluid channel 18 connects the two-stage pump chamber, transferring gas and liquid for two-stage compression. The front distribution plate 9 and the rear distribution plate 7 are both equipped with magnetic poles that repel the magnetic poles of the rotor 15, ensuring that the impeller rotor and the distribution plate do not contact each other.

[0041] Implementation example Figure 6 As shown, three concave, blind-ended radial liquid distribution channels 27 are located between the adapter plate 8 and the pivot shaft 2. These channels allow liquid to flow between the secondary chamber 6 and the primary chamber 14, acting as a pressure relief device. These channels 27 are flush with the surface of the pivot shaft 2. The service liquid pressure in these channels creates a hydrodynamic bearing between the second bearing 16 and the front thrust plate 17, allowing a non-contact bearing to support the impeller's rotation while maintaining accurate axial clearance between the adapter plate 8 and the rotor 15.

[0042] The pumping capacity of the water ring vacuum pump can also be adjusted by changing the axial length of the impeller and the pivot 2 without redesigning any other components of the pump. The material selection of the pump components has good corrosion resistance and can resist a variety of corrosive substances encountered in the exhaust gas flow of the processing chamber. The pivot 2 and the front thrust plate 17 and the rear thrust plate 4 can be made of high-purity bauxite, sintered silicon carbide or other similar materials. The first bearing 5 and the second bearing 16 are made of self-lubricating materials such as graphite and graphite / PTFE composite materials (but not limited to these). The pump housing 1, the adapter plate 8, and the rotor 15 can be made of a series of polymer materials, such as polyvinyl chloride (PVC), filled polypropylene, polyphenylene sulfide, polyvinylidene fluoride (PVDF), and these materials can also contain PTFE.

[0043] The magnetically driven two-stage water ring vacuum pump can be installed vertically, with the axis usually extending vertically. The vertical installation of the pump allows the gas inlet 21 to be parallel to the axis. The gas flow carrying particles discharged from the processing chamber can enter the pump chamber smoothly, reducing the possibility of blockage (for example, in the piping system). Service liquid is supplied under the pressure of the liquid ring to flush the inlet path, thereby further reducing the possibility of blockage. Vertical installation also significantly reduces its footprint. Using an exhaust gas outlet 11 perpendicular to the axis (i.e. parallel to the ground) allows the gas / liquid separator tank to be very tightly coupled, further optimizing the packaging of the pump and reducing the footprint.

[0044] The working principle is:

[0045] The magnetically driven two-stage water ring vacuum pump transmits power through a magnetic coupling system, replacing traditional mechanical seal designs for completely leak-free operation and ensuring that the medium in the pump chamber is isolated from the outside world. The pump utilizes a two-stage blade design that progressively compresses the gas, effectively improving vacuum levels and operating efficiency, and maintaining efficient pumping performance at lower pressures. Magnetic drive technology not only improves equipment reliability, avoids seal wear and leakage, but also reduces operating and maintenance costs. Its design is particularly suitable for handling corrosive, toxic, volatile gases, or gases containing water vapor. This sophisticated design enables the water ring vacuum pump to achieve efficient and stable exhaust gas treatment under various operating conditions, ensuring long-term stable system operation and reducing energy consumption.

[0046] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0047] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A magnetically driven two-stage water ring vacuum pump, characterized in that: The invention comprises a pump housing, an adapter body (8) and a magnetic drive assembly; the pump housing is divided into two pump chambers by the adapter body (8), wherein a rotatable rotor is eccentrically installed in each pump chamber, the rotor having a plurality of blades (28) and being used to compress a medium transported from an inlet of the pump chamber to an outlet through the rotation of the blades (28); a magnetic unit is installed in the rotor; A gas flow channel and a service liquid flow channel are provided between the adapter (8) and the two pump chambers. The gas flow channel is used to input corrosive gas into the pump chamber for treatment and output the treated gas; the service liquid flow channel is used to transport the service liquid for treating the corrosive gas into the pump chamber and output corrosion products; and the magnetic drive assembly drives the rotor to rotate through a magnetic field.

2. The magnetically driven two-stage water ring vacuum pump according to claim 1, characterized in that: A pivot (2) is installed in the pump housing, and the pivot (2) passes through the adapter (8) and two pump chambers; the rotor is supported on the pivot (2); and the pivot (2) eccentrically passes through the pump chamber.

3. The magnetically driven two-stage water ring vacuum pump according to claim 1, characterized in that: The adapter body (8) is respectively provided with a gas inlet (21), a gas outlet (11), a water inlet (19) and a drain outlet (22); the gas inlet (21) and the water inlet (19) are respectively communicated with one pump chamber, the gas outlet (11) and the water outlet (22) are respectively communicated with the other pump chamber; a fluid channel (18) communicating with the two pump chambers is provided in the adapter body (8); the gas inlet (21), one pump chamber, the fluid channel (18), the other pump chamber and the gas outlet (11) constitute a gas flow channel; the water inlet (19), one pump chamber, the fluid channel (18), the other pump chamber and the drain outlet (22) constitute a service liquid flow channel.

4. The magnetically driven two-stage water ring vacuum pump according to claim 1, characterized in that: The magnetic drive assembly comprises a driven permanent magnet (13) and a stator winding (20), wherein the driven permanent magnet (13) is driven by the stator winding (20), and the driven permanent magnet (13) is located inside the rotor; the stator winding (20) is located inside the pump casing; and an isolation sleeve (3) is installed between the stator winding (20) and the driven permanent magnet (13).

5. The magnetically driven two-stage water ring vacuum pump according to claim 1, characterized in that: The center of the rotor is provided with a hub for mounting a support body, and a groove is provided between the hub and the edge of the rotor; the hub is mounted on a pivot (2) through the support body; blades (28) are mounted in the groove outside the hub; distribution plates are respectively mounted on both sides of the adapter (8), one side of the distribution plate has a protrusion extending axially into the groove of the rotor, and an eccentric hole (29) in the protrusion is sleeved on the outside of the blade (28); the eccentric hole (29) and the wall of the groove form a pump chamber.

6. The magnetically driven two-stage water ring vacuum pump according to claim 2, characterized in that: The service fluid entering the pump is transported between the pivot (2) and the rotor for lubricating and flushing the outer surface of the pivot; an axially or / and radially extending channel is provided between the pivot (2) and the rotor for transporting the service fluid to the pivot (2).

7. The magnetically driven two-stage water ring vacuum pump according to claim 5, characterized in that: At least one pair of repulsive anti-touch magnets (10) is installed inside one end of the rotor and inside the distribution plate.

8. The magnetically driven two-stage water ring vacuum pump according to claim 2, characterized in that: The two ends of the pivot (2) are mounted in the pump housing via thrust plates; the rotor (15) includes a bearing surface for cooperating with the thrust plate, and the service fluid entering the pump is guided between the bearing surface and the thrust plate to form a non-contact fluid dynamic axial bearing.

9. The magnetically driven two-stage water ring vacuum pump according to claim 2, characterized in that: At least one concave blind-end radial liquid distribution channel (27) is provided between the adapter plate (8) and the pivot (2) for allowing liquid to flow between the two chambers.

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