Vacuum pump combination

Abstract

This invention belongs to the field of vacuum pump technology, specifically relating to vacuum pump assemblies. Addressing the shortcomings of existing dry-volume vacuum pump and centrifugal vacuum pump assemblies, which offer only a single operating mode, this invention adopts the following technical solution: The vacuum pump assembly includes: a centrifugal unit; a dry-volume unit; a channel switching device; the centrifugal unit and the dry-volume unit are controlled independently; the channel switching device is configured to allow the vacuum pump assembly to switch between at least two of the following operating modes: Mode 1: The inlet end of the centrifugal unit is connected to the evacuated container, and the outlet end is connected to the atmosphere; Mode 2: The inlet end of the centrifugal unit is connected to the evacuated container, the outlet end is connected to the inlet end of the dry-volume unit, and the outlet end of the dry-volume unit is connected to the atmosphere; Mode 3: The inlet end of the dry-volume unit is connected to the evacuated container, the outlet end is connected to the inlet end of the centrifugal unit, and the outlet end of the centrifugal unit is connected to the atmosphere. The beneficial effect of this invention is that it provides multiple operating modes.

Description

Technical Field

[0001] This invention belongs to the field of vacuum pump technology, and specifically relates to vacuum pump assemblies. Background Technology

[0002] Dry positive displacement vacuum pumps and centrifugal vacuum pumps are two widely used types of vacuum pumps. When used alone for evacuation, dry positive displacement vacuum pumps are larger and consume more power than centrifugal vacuum pumps, especially when high pumping speeds are required at rough vacuum levels. Centrifugal vacuum pumps, on the other hand, have poor ultimate vacuum levels when used alone, and their efficiency decreases further with decreasing inlet pressure, while their operating temperature rises sharply.

[0003] Currently, some solutions combine different types of vacuum pumps, such as Roots-rotary vane combination and screw-Roots combination. The combination forms are divided into compound vacuum pumps and vacuum pump units. The former emphasizes the integration of internal structural principles, while the latter emphasizes the complete system-level combination.

[0004] However, existing technologies rarely combine dry positive displacement vacuum pumps and centrifugal vacuum pumps. Furthermore, the very few existing combinations of dry positive displacement vacuum pumps and centrifugal vacuum pumps operate in a single mode and fail to fully realize the combined effect. Summary of the Invention

[0005] This invention addresses the limitation of existing positive displacement centrifugal vacuum pump combinations in terms of their single operating mode by providing a vacuum pump combination that integrates a dry positive displacement vacuum pump and a centrifugal vacuum pump. This combination offers multiple operating modes, enhancing adaptability. The dry positive displacement vacuum pump and the centrifugal vacuum pump can be in the form of a combined vacuum pump or a vacuum pump unit.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a vacuum pump assembly, the vacuum pump assembly comprising: At least one centrifugal vacuum unit; At least one dry volumetric vacuum unit; Channel switching device; Among them, the centrifugal vacuum unit and the dry volumetric vacuum unit are controlled separately; The channel switching device is configured to switch between at least two of the following operating modes when the vacuum pump assembly is operating: Working mode 1: The inlet of the centrifugal vacuum unit is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. Working mode 2: The inlet of the centrifugal vacuum unit is connected to the container being evacuated, and the outlet is connected to the inlet of the dry volumetric vacuum unit. The outlet of the dry volumetric vacuum unit is connected to the recovery container or the atmosphere. In working mode 3, the inlet of the dry volumetric vacuum unit is connected to the container being evacuated, and the outlet is connected to the inlet of the centrifugal vacuum unit. The outlet of the centrifugal vacuum unit is connected to the recovery container or the atmosphere.

[0007] The vacuum pump assembly of this invention combines a centrifugal vacuum unit and a dry volumetric vacuum unit and incorporates a channel switching device. This device enables three operating modes for the vacuum pump assembly. In the first operating mode, only the centrifugal vacuum unit operates, utilizing its high efficiency for evacuation during the coarse evacuation stage. In the second operating mode, the centrifugal vacuum unit and the dry volumetric vacuum unit are connected in series, operating simultaneously. The centrifugal vacuum unit performs pre-evacuation, resulting in lower energy consumption and lower power consumption for the dry volumetric vacuum unit. In the third operating mode, the dry volumetric vacuum unit and the centrifugal vacuum unit are connected in series, operating simultaneously (the centrifugal vacuum unit can operate intermittently). This provides optimal exhaust pressure for the dry volumetric vacuum unit, reduces the compression ratio of the volumetric pump, improves the manufacturability of the dry volumetric vacuum unit, reduces backflow, and enhances the vacuum level. Furthermore, the centrifugal vacuum pump unit may also include the dry volumetric vacuum unit.

[0008] As an improvement, in working mode two, when the pressure in the container being pumped is higher than the set threshold, the centrifugal vacuum unit is in the main pumping state, and when the pressure in the container being pumped is lower than the set threshold, the dry volumetric vacuum unit is in the main pumping state. In operating mode three, the dry volumetric vacuum unit is in main pumping mode throughout the entire process; the centrifugal vacuum unit maintains the back pressure on the exhaust side of the dry volumetric vacuum unit within a set range below atmospheric pressure. In some preferred embodiments, the vacuum pump assembly has at least operating modes two and three.

[0009] As an improvement, the vacuum pump assembly has only one centrifugal vacuum unit and one dry volumetric vacuum unit. In the working mode, the centrifugal vacuum unit is working, while the dry volumetric vacuum unit is not working. In operating mode two, both the centrifugal vacuum unit and the dry volumetric vacuum unit are in operation; In operating mode three, both the centrifugal vacuum unit and the dry volumetric vacuum unit are in operation.

[0010] As an improvement, First three passages; First check valve; Second and third passages; Third passage; Second check valve; First control valve; Fourth and third passages; Fifth and third passages; Third check valve; Fourth check valve; Second control valve; pipeline; In the first working mode, the pumped container, the first three-way valve, the first check valve, the second three-way valve, the centrifugal vacuum unit, the third three-way valve, the second check valve, the recovery container, or the atmosphere are connected in sequence. In working mode two, the pumped container, the first three-way valve, the first one-way valve, the second three-way valve, the centrifugal vacuum unit, the third three-way valve, the first control valve, the fourth three-way valve, the dry volumetric vacuum unit, the fifth three-way valve, the third one-way valve, the recovery container, or the atmosphere are connected in sequence. In operating mode three, the pumped container, the fourth one-way valve, the dry volumetric vacuum unit, the fifth three-way valve, the second control valve, the second three-way valve, the centrifugal vacuum unit, the third three-way valve, the second one-way valve, the recovery container, or the atmosphere are connected in sequence.

[0011] As an improvement, the impeller of the centrifugal vacuum unit adopts a backward-curved split-flow blade structure, and the impeller outlet is equipped with an angle-adjustable guide vane, the angle of which can be adjusted as the pressure in the evacuated container decreases; and / or, The impeller surface of the centrifugal vacuum unit is provided with a hydrophobic and corrosion-resistant coating; and / or, The pumping speed of a centrifugal vacuum unit is 1.2-1.5 times that of a dry volumetric vacuum unit; and / or, The high-efficiency operating pressure range of centrifugal vacuum units is greater than that of dry volumetric vacuum units; and / or, The power of a centrifugal vacuum unit is less than that of a dry volumetric vacuum unit; and / or, Centrifugal vacuum units include an inducer wheel; and / or, In operating mode three, the dry volumetric vacuum unit operates continuously, while the centrifugal vacuum unit operates intermittently or at a speed below its rated speed; and / or, During the transition from working mode two to working mode three, the centrifugal vacuum unit first slows down and then speeds up.

[0012] As an improvement, the vacuum pump assembly includes a centrifugal vacuum unit one, a centrifugal vacuum unit two, and a dry volumetric vacuum unit. In the first working mode, the inlet of the centrifugal vacuum unit is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. In working mode two, the inlet of centrifugal vacuum unit one is connected to the container being evacuated, the outlet is connected to the inlet of dry volumetric vacuum unit, and the outlet of dry volumetric vacuum unit is connected to the recovery container or the atmosphere. In operating mode three, the inlet of the dry volumetric vacuum unit is connected to the container being evacuated, the outlet is connected to the inlet of the centrifugal vacuum unit two, and the outlet of the centrifugal vacuum unit two is connected to the recovery container or the atmosphere.

[0013] As an improvement, in the first working mode, centrifugal vacuum unit one is working, while dry volumetric vacuum unit and centrifugal vacuum unit two are not working. In working mode two, both centrifugal vacuum unit one and dry volumetric vacuum unit one are working, while centrifugal vacuum unit two is not working. In operating mode three, both centrifugal vacuum unit two and dry volumetric vacuum unit are working, while centrifugal vacuum unit one is turned off after its speed is reduced.

[0014] As an improvement, the channel switching device includes: Three connections and one channel; One-way valve; Three-way connection; One-way valve two; Three-way connection; Three-way four; One-way valve three; One-way valve four; One-way valve five; pipeline; In the first working mode, the pumped container, three-way valve one, one-way valve one, centrifugal vacuum unit one, three-way valve two, one-way valve two, recovery container or atmosphere are connected in sequence. In working mode two, the pumped container, three-way valve one, one-way valve one, centrifugal vacuum unit one, three-way valve two, three-way valve three, dry volumetric vacuum unit, three-way valve four, one-way valve three, recovery container or atmosphere are connected in sequence; In working mode three, the pumped container, one-way valve four, three-way valve three, dry volumetric vacuum unit, three-way valve four, centrifugal vacuum unit two, one-way valve five, recovery container or atmosphere are connected in sequence.

[0015] As an improvement, the pumping speed of centrifugal vacuum unit one is 1.2-1.5 times that of dry volumetric vacuum unit; and / or, The high-efficiency operating pressure range of centrifugal vacuum unit one is greater than that of dry volumetric vacuum unit; and / or, The power of a dry volumetric vacuum unit is greater than that of a centrifugal vacuum unit; and / or, The power of a dry volumetric vacuum unit is greater than that of a centrifugal vacuum unit. Centrifugal vacuum unit two includes an inducer wheel; and / or, In operating mode three, the dry volumetric vacuum unit works continuously, while the centrifugal vacuum unit two works intermittently or operates at a speed lower than the rated speed.

[0016] As an improvement, the vacuum pump combination is a compound vacuum pump or a vacuum pump unit.

[0017] The beneficial effects of the vacuum pump combination of the present invention are: combining a centrifugal vacuum unit and a dry volumetric vacuum unit and setting a channel switching device, the channel switching device realizes the switching between at least two of the three working modes of the vacuum pump combination during operation; the three working modes have their own advantages, so that they can be applied to different scenarios and / or different working stages in the same scenario. Attached Figure Description

[0018] Figure 1 This is a structural block diagram of the vacuum pump assembly according to Embodiment 1 of the present invention.

[0019] Figure 2 This is a structural block diagram of the vacuum pump assembly according to Embodiment 2 of the present invention.

[0020] Figure 3 This is a structural block diagram of the vacuum pump assembly according to Embodiment 3 of the present invention.

[0021] Figure 4 This is a structural block diagram of the vacuum pump assembly according to Embodiment 4 of the present invention.

[0022] In the diagram, 1. First tee; 2. First check valve; 3. Second and third passages; 4. The third three-way junction; 5. Second check valve; 6. First control valve; 7. Fourth three-way; 8. Fifth Three-Way Pass; 9. Third check valve; 10. Fourth check valve; 11. Second control valve; 12. Pipeline; 13. Three connections and one outlet; 14. One-way valve; 15. Three-way connection, two-way connection; 16. One-way valve two; 17. Three-way connection; 18. Three-way connection; 19. One-way valve three; 20. One-way valve four; 21. One-way valve five; CP, centrifugal vacuum unit; PP, dry volumetric vacuum unit; CP1, Centrifugal Vacuum Unit 1; CP2, Centrifugal Vacuum Unit Two. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be explained and described below. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0024] See Figures 1 to 4 The vacuum pump assembly of this invention includes: At least one centrifugal vacuum unit; At least one dry volumetric vacuum unit; Channel switching device; Among them, the centrifugal vacuum unit and the dry volumetric vacuum unit are controlled separately; The channel switching device is configured such that the vacuum pump assembly has at least the following operating modes: Working mode 1: The inlet of the centrifugal vacuum unit is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. Working mode 2: The inlet of the centrifugal vacuum unit is connected to the container being evacuated, and the outlet is connected to the inlet of the dry volumetric vacuum unit. The outlet of the dry volumetric vacuum unit is connected to the recovery container or the atmosphere. In working mode 3, the inlet of the dry volumetric vacuum unit is connected to the container being evacuated, and the outlet is connected to the inlet of the centrifugal vacuum unit. The outlet of the centrifugal vacuum unit is connected to the recovery container or the atmosphere.

[0025] The vacuum pump assembly of this invention combines a centrifugal vacuum unit and a dry volumetric vacuum unit and includes a channel switching device. This device enables three operating modes for the vacuum pump assembly. In the first operating mode, only the centrifugal vacuum unit operates, utilizing its high efficiency for evacuation during the coarse evacuation stage. In the second operating mode, the centrifugal vacuum unit and the dry volumetric vacuum unit are connected in series, operating simultaneously. The centrifugal vacuum unit performs pre-evacuation, resulting in lower energy consumption and lower power consumption for the dry volumetric vacuum unit. In the third operating mode, the dry volumetric vacuum unit and the centrifugal vacuum unit are connected in series, operating simultaneously (the centrifugal vacuum unit can operate intermittently). This provides optimal exhaust pressure for the dry volumetric vacuum unit, reduces the compression ratio of the volumetric pump, improves the manufacturability of the dry volumetric vacuum unit, reduces backflow, and increases the vacuum level. Furthermore, the centrifugal vacuum pump unit may also include a dry volumetric vacuum unit.

[0026] Example 1 See Figure 1 The vacuum pump assembly of Embodiment 1 of the present invention includes: A centrifugal vacuum unit CP; A dry volumetric vacuum unit PP; Channel switching device; Among them, the centrifugal vacuum unit CP and the dry volumetric vacuum unit PP are controlled separately; The channel switching device is configured to enable the vacuum pump assembly to operate in the following modes: Working mode 1: The inlet of the centrifugal vacuum unit CP is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. Working Mode 2: The inlet of the centrifugal vacuum unit CP is connected to the container being evacuated, and the outlet is connected to the inlet of the dry volumetric vacuum unit PP. The outlet of the dry volumetric vacuum unit PP is connected to the recovery container or the atmosphere. In working mode 3, the inlet of the dry volumetric vacuum unit PP is connected to the container being evacuated, and the outlet is connected to the inlet of the centrifugal vacuum unit CP. The outlet of the centrifugal vacuum unit CP is connected to the recovery container or the atmosphere.

[0027] In this embodiment, operating mode two is suitable for scenarios requiring high instantaneous pumping speed and shorter vacuuming time. Operating mode three is suitable for scenarios with harsh working environments, such as pumping high water vapor conditions.

[0028] In this embodiment, operating mode one, operating mode two, and operating mode three are switched sequentially. In other embodiments, the switching order of each operating mode can be adjusted as needed.

[0029] In this embodiment, when the pressure in the pumped container reaches the first preset threshold, the system switches from working mode one to working mode two. When the pressure in the pumped container reaches the second preset threshold, the system switches from working mode two to working mode three. The first preset threshold is greater than the second preset threshold.

[0030] In this embodiment, in the first working mode, the centrifugal vacuum unit CP is working, while the dry volumetric vacuum unit PP is not working. In operating mode two, both the centrifugal vacuum unit CP and the dry volumetric vacuum unit PP are working; In operating mode three, both the centrifugal vacuum unit CP and the dry volumetric vacuum unit PP are working.

[0031] In this embodiment, the channel switching device includes: First three-way connector 1; First check valve 2; Second three-way 3; Third three-way 4; Second check valve 5; First control valve 6; Fourth Three Pass 7; Fifth Third Pass 8; Third check valve 9; Fourth check valve 10; Second control valve 11; Pipeline 12; In the first operating mode, the pumped container, the first three-way valve 1, the first one-way valve 2, the second three-way valve 3, the centrifugal vacuum unit CP, the third three-way valve 4, the second one-way valve 5, and the recovery container or atmosphere are connected in sequence; the airflow path in the first operating mode is as follows: Figure 1 As shown by the red dashed line in the middle; In operating mode two, the pumped container, first three-way valve 1, first one-way valve 2, second three-way valve 3, centrifugal vacuum unit CP, third three-way valve 4, first control valve 6, fourth three-way valve 7, dry volumetric vacuum unit PP, fifth three-way valve 8, third one-way valve 9, and recovery container or atmosphere are connected in sequence; the airflow path in operating mode two is as follows: Figure 1 As shown by the blue dashed line in the image; In operating mode three, the pumped container, fourth one-way valve 10, dry volumetric vacuum unit PP, fifth three-way valve 8, second control valve 11, second three-way valve 3, centrifugal vacuum unit CP, third three-way valve 4, second one-way valve 5, and recovery container or atmosphere are connected in sequence; the airflow path in operating mode three is as follows: Figure 1 As shown by the green dashed line in the image.

[0032] In this embodiment, the first control valve 6 and the second control valve 11 are closed, the centrifugal vacuum unit CP is activated, the dry volumetric vacuum unit PP is not activated, and the system enters working mode one. The gas in the evacuated container flows along... Figure 1 The red dashed line in the middle flows.

[0033] In this embodiment, when the pressure in the evacuated container reaches the first preset threshold, the second control valve 11 opens, activating the dry volumetric vacuum unit PP and entering working mode two. The gas in the evacuated container then flows along... Figure 1 The blue dashed line flows.

[0034] In this embodiment, when the pressure in the pumped container reaches the second preset threshold, the second control valve 11 is closed and the first control valve 6 is opened, entering working mode three. The centrifugal vacuum unit CP first decelerates and then accelerates, and the gas in the pumped container moves along... Figure 1 The green dashed line flows.

[0035] In this embodiment, the pumping speed of the centrifugal vacuum unit CP is 1.2-1.5 times that of the dry volumetric vacuum unit PP.

[0036] In this embodiment, the high-efficiency operating range of the centrifugal vacuum unit CP is when the pressure of the recovery container or atmospheric pressure reaches a first preset threshold, and the high-efficiency operating range of the dry volumetric vacuum unit PP is greater than or equal to the first preset threshold.

[0037] In this embodiment, the power of the centrifugal vacuum unit CP is less than that of the dry volumetric vacuum unit PP.

[0038] In this embodiment, the centrifugal vacuum unit CP includes an induction wheel.

[0039] In this embodiment, under operating mode three, the dry volumetric vacuum unit PP operates continuously, while the centrifugal vacuum unit CP operates intermittently.

[0040] In this embodiment, during the process of switching from working mode two to working mode three, the centrifugal vacuum unit CP first slows down and then speeds up.

[0041] In this embodiment, in the first working mode, only the centrifugal vacuum unit CP works, utilizing the high efficiency of the centrifugal vacuum pumping unit in the rough pumping stage from low to medium vacuum.

[0042] In this embodiment, under operating mode two, the centrifugal vacuum unit CP and the dry volumetric vacuum unit PP are connected in series and both operate, which improves the pumping speed of the fine pumping stage from medium vacuum to high vacuum; the power of the volumetric pump can be reduced; through parameterized design and reasonable allocation of pumping speed ratio, efficiency can be maximized.

[0043] In this embodiment, under operating mode three, the dry volumetric vacuum unit PP and the centrifugal vacuum unit CP are connected in series and both operate. The centrifugal vacuum unit CP can provide the optimal exhaust port pressure for the dry volumetric vacuum pump, reduce the pressure ratio design of the volumetric pump, and improve the manufacturability of the volumetric pump. The centrifugal vacuum unit CP can reduce the backflow of the volumetric pump and improve the ultimate vacuum. The centrifugal vacuum unit CP can protect the dry volumetric vacuum unit PP. The gas passage structure of the centrifugal vacuum pump is simple, which is conducive to the removal of dust and water vapor. The centrifugal vacuum pump has low precision requirements for the manufacture of parts, few components, and can be made of special materials. It can be used in some harsh working conditions, such as high moisture / corrosion scenarios, and has a wider range of applications.

[0044] In this embodiment, the centrifugal vacuum unit CP includes a centrifugal pump motor and a centrifugal rotor, and the dry volumetric vacuum unit PP includes a volumetric pump motor and a volumetric rotor. The centrifugal pump motor and the volumetric pump motor are controlled to achieve their respective start-stop and / or speed regulation.

[0045] In this embodiment, both the first control valve 6 and the second control valve 11 are solenoid valves. Other valves that need to be controlled can also be solenoid valves to achieve automatic control.

[0046] In this embodiment, the vacuum pump assembly is a compound vacuum pump, which includes a pump body. A portion of the pipe 12 is formed by a channel within the pump body.

[0047] In this embodiment, there may also be a working mode in which only the dry volumetric vacuum unit PP works (the airflow does not or hardly passes through the centrifugal vacuum unit CP).

[0048] The beneficial effects of the vacuum pump combination in Embodiment 1 of the present invention are as follows: the centrifugal vacuum unit CP and the dry volumetric vacuum unit PP are combined and a channel switching device is set up. The channel switching device realizes three working modes of the vacuum pump combination. The three working modes have their own advantages, so they can be applied to different scenarios and / or different working stages in the same scenario. The working mode can be switched during the working process. The mode switching is convenient.

[0049] Example 2 See Figure 2 In this embodiment, the vacuum pump assembly includes a centrifugal vacuum unit CP1, a centrifugal vacuum unit CP2, and a dry volumetric vacuum unit PP.

[0050] In this embodiment, in the first working mode, the inlet of the centrifugal vacuum unit CP1 is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. In working mode two, the inlet of centrifugal vacuum unit CP1 is connected to the container being evacuated, and the outlet is connected to the inlet of dry volumetric vacuum unit PP. The outlet of dry volumetric vacuum unit PP is connected to the recovery container or the atmosphere. In operating mode three, the inlet of the dry volumetric vacuum unit PP is connected to the container being evacuated, and the outlet is connected to the inlet of the centrifugal vacuum unit CP2. The outlet of the centrifugal vacuum unit CP2 is connected to the recovery container or the atmosphere.

[0051] In this embodiment, in the first working mode, centrifugal vacuum unit CP1 is working, while dry volumetric vacuum unit PP and centrifugal vacuum unit CP2 are not working. In working mode two, centrifugal vacuum unit CP1 and dry volumetric vacuum unit PP are both working, while centrifugal vacuum unit CP2 is not working. In operating mode three, both centrifugal vacuum unit CP2 and dry volumetric vacuum unit PP are working, while centrifugal vacuum unit CP1 shuts down after its speed is reduced.

[0052] In this embodiment, the channel switching device includes: Three-way connector 13; One-way valve 14; Three-way connector 2.15; One-way valve 2 16; Three-way three-17; Three-way four-18; One-way valve 319; One-way valve 420; One-way valve 521; Pipeline 12; In the first working mode, the pumped container, three-way valve 13, one-way valve 14, centrifugal vacuum unit CP1, three-way valve 2 15, one-way valve 2 16, and recovery container or atmosphere are connected in sequence; the airflow path in the first working mode is as follows: Figure 2 As shown by the red dashed line in the middle; In operating mode two, the pumped container, three-way valve 13, one-way valve 14, centrifugal vacuum unit CP1, three-way valve 2 15, three-way valve 3 17, dry volumetric vacuum unit PP, three-way valve 4 18, one-way valve 3 19, and recovery container or atmosphere are connected in sequence; the airflow path in operating mode two is as follows: Figure 2 As shown by the blue dashed line; In operating mode three, the evacuated container, one-way valve four 20, three-way valve three 17, dry volumetric vacuum unit PP, three-way valve four 18, centrifugal vacuum unit two CP2, one-way valve five 21, and recovery container or atmosphere are connected in sequence; the airflow path in operating mode three is as follows: Figure 2 As shown by the purple dashed line in the middle.

[0053] In this embodiment, the pumping speed of the centrifugal vacuum unit CP1 is 1.2-1.5 times that of the dry volumetric vacuum unit PP.

[0054] In this embodiment, the high-efficiency operating range of the centrifugal vacuum unit CP1 is when the pressure of the recovery container or atmospheric pressure reaches a first preset threshold, and the high-efficiency operating range of the dry volumetric vacuum unit PP is greater than or equal to the first preset threshold.

[0055] In this embodiment, the power of the dry volumetric vacuum unit PP is greater than that of the centrifugal vacuum unit CP1.

[0056] In this embodiment, the power of the dry volumetric vacuum unit PP is greater than that of the centrifugal vacuum unit CP2.

[0057] In this embodiment, the centrifugal vacuum unit CP2 includes an induction wheel.

[0058] In this embodiment, under operating mode three, the dry volumetric vacuum unit PP operates continuously, while the centrifugal vacuum unit CP2 operates intermittently.

[0059] In this embodiment, the vacuum pump combination is a compound vacuum pump or a vacuum pump unit.

[0060] The main difference between Example 2 and Example 1 is that an additional centrifugal vacuum unit CP is configured.

[0061] The vacuum pump assembly in this embodiment can switch operating modes during operation; mode switching is convenient.

[0062] In this embodiment, there may also be a working mode in which only the dry volumetric vacuum unit PP works (the airflow does not or hardly passes through the centrifugal vacuum unit CP1 and the centrifugal vacuum unit CP2).

[0063] In other embodiments, more operating modes can be achieved by modifying the channel switching device. For example, in operating mode four, the pumped container, centrifugal vacuum unit CP1, dry volumetric vacuum unit PP, and centrifugal vacuum unit CP2 are connected in sequence.

[0064] Example 3 See Figure 3 In this embodiment, the channel switching device is configured to enable the vacuum pump assembly to have the following operating modes: Working mode 1: The inlet of the centrifugal vacuum unit CP is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. Working Mode 2: The inlet of the centrifugal vacuum unit CP is connected to the container being evacuated, and the outlet is connected to the inlet of the dry volumetric vacuum unit PP. The outlet of the dry volumetric vacuum unit PP is connected to the recovery container or the atmosphere.

[0065] In this embodiment, the vacuum pump assembly does not have operating mode three.

[0066] In this embodiment, the channel switching device includes a first one-way valve 2, a vacuum centrifuge unit CP, a third three-way valve 4, a second one-way valve 5, a dry volumetric vacuum pump unit PP, and a third one-way valve 9. The first one-way valve 2, the vacuum centrifuge unit CP, the third three-way valve 4, the dry volumetric vacuum pump unit PP, and the third one-way valve 9 are connected in series, and the second one-way valve 5 is connected to the third three-way valve 4.

[0067] In the first operating mode, the evacuated container, the first one-way valve 2, the centrifugal vacuum unit CP, the third three-way valve 4, the second one-way valve 5, and the recovery container or atmosphere are connected in sequence. At this time, the centrifugal vacuum unit CP is operational, while the dry volumetric vacuum unit PP is not operational. The airflow path in the first operating mode is as follows: Figure 3 As shown by the red dashed line.

[0068] In operating mode two, the evacuated container, the first one-way valve 2, the centrifugal vacuum unit CP, the third three-way valve 4, the dry volumetric vacuum unit PP, the third one-way valve 9, and the recovery container or atmosphere are connected in sequence. At this time, both the centrifugal vacuum unit CP and the dry volumetric vacuum unit PP are operational. The airflow path in operating mode two is as follows: Figure 3 As shown by the blue dashed line.

[0069] In this embodiment, a valve can be installed between the third three-way valve 4 and the dry volumetric vacuum unit PP. Other one-way valves can also be configured as controllable one-way valves.

[0070] The vacuum pump assembly in this embodiment can switch operating modes during operation; mode switching is convenient.

[0071] Example 4 See Figure 4 In this embodiment, the channel switching device is configured to enable the vacuum pump assembly to have the following operating modes: Working mode 1: The inlet of the centrifugal vacuum unit CP is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. In working mode 3, the inlet of the dry volumetric vacuum unit PP is connected to the container being evacuated, and the outlet is connected to the inlet of the centrifugal vacuum unit CP. The outlet of the centrifugal vacuum unit CP is connected to the recovery container or the atmosphere.

[0072] In this embodiment, the vacuum pump assembly does not have operating mode two.

[0073] In this embodiment, the channel switching device includes a first three-way valve 1, a first one-way valve 2, a second three-way valve 3, a vacuum centrifuge unit CP, a second one-way valve 5, a fourth one-way valve 10, and a dry volumetric vacuum pump unit PP. The first three-way valve 1, the first one-way valve 2, the second three-way valve 3, the vacuum centrifuge unit CP, and the second one-way valve 5 are connected in series. The fourth one-way valve 10 and the dry volumetric vacuum pump unit PP are connected in series. The inlet end of the fourth one-way valve 10 is connected to the first three-way valve 1, and the outlet end is connected to the inlet end of the dry volumetric vacuum pump unit PP. The outlet end of the dry volumetric vacuum pump unit PP is connected to the second three-way valve 3.

[0074] In the first operating mode, the evacuated container, the first three-way valve 1, the first one-way valve 2, the second three-way valve 3, the centrifugal vacuum unit CP, the second one-way valve 5, and the recovery container or atmosphere are connected in sequence. At this time, the centrifugal vacuum unit CP is operational, while the dry volumetric vacuum unit PP is not operational. The airflow path in the first operating mode is as follows: Figure 4 As shown by the red dashed line.

[0075] In operating mode three, the evacuated container, fourth one-way valve 10, dry volumetric vacuum pump unit PP, second three-way valve 3, vacuum centrifugal unit CP, second one-way valve 5, and recovery container or atmosphere are connected in sequence. At this time, both the centrifugal vacuum unit CP and the dry volumetric vacuum unit PP are operational. The airflow path in operating mode two is as follows: Figure 4 As shown by the green dashed line.

[0076] In this embodiment, the first check valve 2 and the fourth check valve 10 can be configured as controllable check valves, and a controllable check valve can be installed between the dry volumetric vacuum pump unit PP and the second three-way valve 3. Other check valves can also be configured as controllable check valves.

[0077] The vacuum pump assembly in this embodiment can switch operating modes during operation; mode switching is convenient.

[0078] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the content described in the above specific embodiments. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A vacuum pump assembly, characterized in that: The vacuum pump assembly includes: At least one centrifugal vacuum unit (CP); At least one dry volumetric vacuum unit (PP); Channel switching device; The centrifugal vacuum unit (CP) and the dry volumetric vacuum unit (PP) are controlled separately. The channel switching device is configured to switch between at least two of the following operating modes when the vacuum pump assembly is operating: Working mode 1: The inlet of the centrifugal vacuum unit (CP) is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. Working Mode 2: The inlet of the centrifugal vacuum unit (CP) is connected to the container being evacuated, and the outlet is connected to the inlet of the dry volumetric vacuum unit (PP). The outlet of the dry volumetric vacuum unit (PP) is connected to the recovery container or the atmosphere. In working mode 3, the inlet of the dry volumetric vacuum unit (PP) is connected to the container being evacuated, and the outlet is connected to the inlet of the centrifugal vacuum unit (CP). The outlet of the centrifugal vacuum unit (CP) is connected to the recovery container or the atmosphere.

2. The vacuum pump assembly according to claim 1, characterized in that: In working mode two, when the pressure in the container being pumped is higher than the set threshold, the centrifugal vacuum unit is in the main pumping state; when the pressure in the container being pumped is lower than the set threshold, the dry volumetric vacuum unit is in the main pumping state. In operating mode three, the dry volumetric vacuum unit is in the main pumping state throughout the entire process; the centrifugal vacuum unit maintains the back pressure on the exhaust side of the dry volumetric vacuum unit within a set range below atmospheric pressure.

3. The vacuum pump assembly according to claim 1 or 2, characterized in that: The vacuum pump assembly consists of only one centrifugal vacuum unit (CP) and one dry volumetric vacuum unit (PP). In the working mode, the centrifugal vacuum unit (CP) is working, while the dry volumetric vacuum unit (PP) is not working; In operating mode two, both the centrifugal vacuum unit (CP) and the dry volumetric vacuum unit (PP) are in operation; In operating mode three, both the centrifugal vacuum unit (CP) and the dry volumetric vacuum unit (PP) are in operation.

4. The vacuum pump assembly according to claim 3, characterized in that: The channel switching device includes: First three passages (1); First check valve (2); Second and third passages (3); Third passage (4); Second check valve (5); First control valve (6); Fourth Third Pass (7); Fifth Third Pass (8); Third check valve (9); Fourth check valve (10); Second control valve (11); Pipeline (12); In the first working mode, the pumped container, the first three-way valve (1), the first one-way valve (2), the second three-way valve (3), the centrifugal vacuum unit (CP), the third three-way valve (4), the second one-way valve (5), the recovery container or the atmosphere are connected in sequence; In working mode two, the pumped container, the first three-way valve (1), the first one-way valve (2), the second three-way valve (3), the centrifugal vacuum unit (CP), the third three-way valve (4), the first control valve (6), the fourth three-way valve (7), the dry volumetric vacuum unit (PP), the fifth three-way valve (8), the third one-way valve (9), the recovery container or the atmosphere are connected in sequence; In working mode three, the pumped container, the fourth one-way valve (10), the dry volumetric vacuum unit (PP), the fifth three-way valve (8), the second control valve (11), the second three-way valve (3), the centrifugal vacuum unit (CP), the third three-way valve (4), the second one-way valve (5), the recovery container, or the atmosphere are connected in sequence.

5. The vacuum pump assembly according to claim 3, characterized in that: The impeller of the centrifugal vacuum unit (CP) adopts a backward-curved split-flow blade structure, and the impeller outlet is equipped with an adjustable guide vane, the angle of which can be adjusted as the pressure in the evacuated container decreases; and / or, The impeller surface of the centrifugal vacuum unit (CP) is provided with a hydrophobic and corrosion-resistant coating; and / or, The pumping speed of a centrifugal vacuum unit (CP) is 1.2-1.5 times that of a dry volumetric vacuum unit (PP); and / or, The high-efficiency operating pressure range of centrifugal vacuum units (CP) is greater than that of dry volumetric vacuum units (PP); and / or, The power of a centrifugal vacuum unit (CP) is less than that of a dry volumetric vacuum unit (PP); and / or, Centrifugal vacuum unit (CP) includes an inducer wheel; and / or, In operating mode three, the dry volumetric vacuum unit (PP) operates continuously, while the centrifugal vacuum unit (CP) operates intermittently or at a speed below its rated speed; and / or, During the transition from working mode two to working mode three, the centrifugal vacuum unit (CP) first slows down and then speeds up.

6. The vacuum pump assembly according to claim 1 or 2, characterized in that: The vacuum pump assembly includes centrifugal vacuum unit one (CP1), centrifugal vacuum unit two (CP2), and a dry volumetric vacuum unit (PP). In the first working mode, the inlet of the centrifugal vacuum unit 1 (CP1) is connected to the container being evacuated, and the outlet is connected to the recovery container or the atmosphere. In working mode two, the inlet of centrifugal vacuum unit one (CP1) is connected to the container being evacuated, the outlet is connected to the inlet of dry volumetric vacuum unit (PP), and the outlet of dry volumetric vacuum unit (PP) is connected to the recovery container or the atmosphere. In operating mode three, the inlet of the dry volumetric vacuum unit (PP) is connected to the container being evacuated, and the outlet is connected to the inlet of the centrifugal vacuum unit two (CP2). The outlet of the centrifugal vacuum unit two (CP2) is connected to the recovery container or the atmosphere.

7. The vacuum pump assembly according to claim 6, characterized in that: In the working mode, centrifugal vacuum unit one (CP1) is working, while dry volumetric vacuum unit (PP) and centrifugal vacuum unit two (CP2) are not working. In operating mode 2, both centrifugal vacuum unit 1 (CP1) and dry volumetric vacuum unit (PP) are working, while centrifugal vacuum unit 2 (CP2) is not working. In operating mode three, both centrifugal vacuum unit two (CP2) and dry volumetric vacuum unit (PP) are working, while centrifugal vacuum unit one (CP1) shuts down after its speed is reduced.

8. The vacuum pump assembly according to claim 6, characterized in that: The channel switching device includes: Three-way connection (13); One-way valve (14); Three-way two (15); One-way valve two (16); Three-way three (17); Three-way four (18); One-way valve three (19); One-way valve four (20); One-way valve five (21); Pipeline (12); In the first working mode, the pumped container, three-way valve one (13), one-way valve one (14), centrifugal vacuum unit one (CP1), three-way valve two (15), one-way valve two (16), recovery container or atmosphere are connected in sequence. In working mode 2, the pumped container, three-way valve 1 (13), one-way valve 1 (14), centrifugal vacuum unit 1 (CP1), three-way valve 2 (15), three-way valve 3 (17), dry volumetric vacuum unit (PP), three-way valve 4 (18), one-way valve 3 (19), recovery container or atmosphere are connected in sequence; In working mode three, the pumped container, one-way valve four (20), three-way three (17), dry volumetric vacuum unit (PP), three-way four (18), centrifugal vacuum unit two (CP2), one-way valve five (21), recovery container or atmosphere are connected in sequence.

9. The vacuum pump assembly according to claim 6, characterized in that: The pumping speed of centrifugal vacuum unit 1 (CP1) is 1.2-1.5 times that of dry volumetric vacuum unit (PP); and / or, The high-efficiency operating pressure range of centrifugal vacuum unit 1 (CP1) is greater than that of dry volumetric vacuum unit (PP); and / or, The power of the dry volumetric vacuum unit (PP) is greater than that of the centrifugal vacuum unit (CP1); and / or, The power of the dry volumetric vacuum unit (PP) is greater than that of the centrifugal vacuum unit 2 (CP2). Centrifugal vacuum unit 2 (CP2) includes an inducer wheel; and / or, In operating mode three, the dry volumetric vacuum unit (PP) operates continuously, while the centrifugal vacuum unit two (CP2) operates intermittently or at a speed lower than the rated speed.

10. The vacuum pump assembly according to claim 1, characterized in that: The vacuum pump combination is either a compound vacuum pump or a vacuum pump unit.

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