Ultra-wide working condition multistage time-sharing series-parallel centrifugal vacuum pump system

Abstract

The invention discloses an ultra-wide working condition multistage time-sharing series-parallel centrifugal vacuum pump system applied to the related field of vacuum pumps, which is characterized in that a first-stage vacuum pump unit, a second-stage centrifugal vacuum pump and a third-stage centrifugal vacuum pump which can be connected in parallel or in series are arranged, and a plurality of switching valves are matched; four time-sharing switching operation modes of independent operation of a first-stage unit, independent operation of a second-stage unit and a third-stage unit, and parallel connection and series connection are realized, so that the system can cover an ultra-wide working condition range from low vacuum degree and high flow to high vacuum degree and low flow, the stable working interval is obviously widened, and the surge margin is increased; in addition, a buffer tank comprising a laminated pressure relief assembly is arranged at each key pipeline node, and a precision regulating valve is arranged on an air inlet pipeline, so that pressure relief or air supply can be performed in a self-adaptive manner during mode switching or air flow sudden change, the pressure fluctuation peak value is effectively inhibited, the problems of gas grabbing and transient pressure impact are solved, and the service life of the system is prolonged. Therefore, the high efficiency and the stability of the system in the operation under the ultra-wide working condition and the long-time-varying working condition are ensured.

Description

Technical Field

[0001] This invention relates to the field of vacuum pumps, and in particular to an ultra-wide operating condition multi-stage time-sharing series-parallel centrifugal vacuum pump system. Background Technology

[0002] In the system design of centrifugal vacuum pumps, the traditional multi-stage pure series mode can improve the system pressure ratio, but it will lead to a narrower stable operating flow range and increase the risk of surge. On the other hand, the multi-stage pure parallel mode can broaden the flow range, but it cannot improve the system pressure ratio and is prone to uneven airflow distribution phenomena such as 'air grabbing', which affects stability.

[0003] Chinese patent CN120231764B discloses a centrifugal vacuum pump set for high flow rate and low pressure, which aims to meet the requirements of high flow rate and high compression ratio at the same time. However, its multi-stage series structure still cannot avoid the inherent disadvantage that the stable operating range decreases with the increase of the number of stages.

[0004] To address the surge problem that easily occurs during series operation, Chinese patent CN111828367A discloses an anti-surge protection device and method for high-speed centrifugal vacuum pumps, which prevents surge and backflow through valve group control, pressure monitoring, and check valves. However, this solution mainly focuses on safety protection and does not solve the fundamental problem of efficient and stable operation of series-parallel combined systems over a wide pressure ratio and flow range. Furthermore, during the series-parallel switching process, transient pressure shocks may occur due to rapid changes in gas momentum, threatening the safety of the pump unit.

[0005] Therefore, for scientific research projects such as hypersonic wind tunnels that simultaneously require a wide pressure ratio range (1-36 or higher), a wide flow range, and long-term variable operating conditions, the traditional combination of multi-stage pure series and multi-stage pure parallel centrifugal vacuum pumps can no longer meet the above-mentioned ultra-wide operating conditions and long-term variable operating conditions.

[0006] Therefore, there is an urgent need to provide a centrifugal vacuum pump system with ultra-wide operating conditions, multi-stage time-sharing series and parallel connection, and the ability to effectively overcome the defect that the working stability decreases with the increase of the number of stages. Summary of the Invention

[0007] 1. Technical problems to be solved The core of this invention lies in effectively solving the problem of decreased stability due to the increase in the number of vacuum pump stages in the prior art by using a multi-stage vacuum pump system with switchable series and parallel operation modes; at the same time, under the action of the buffer tank, it can adaptively depressurize according to the actual gas pressure under different operating conditions.

[0008] 2. Technical Solution To solve the above problems, the present invention adopts the following technical solution.

[0009] A multi-stage time-sharing series-parallel centrifugal vacuum pump system with ultra-wide operating conditions includes an inlet pipe, a primary inlet pipe fixedly connected to the inlet pipe, a three-way splitter pipe fixedly connected to the middle of the primary inlet pipe, a primary vacuum pump unit connected to the three-way splitter pipe, a secondary centrifugal vacuum pump, a tertiary centrifugal vacuum pump, and two frequency converters. A tertiary inlet pipe is fixedly connected between the exhaust end of the secondary centrifugal vacuum pump and the inlet end of the tertiary centrifugal vacuum pump. The primary vacuum pump unit includes two primary centrifugal vacuum pumps. A secondary inlet pipe is fixedly connected between the end of the primary inlet pipe and the inlet of the secondary centrifugal vacuum pump, and a pre-connected parallel switching valve is installed at the connection point. The inlets of the two primary centrifugal vacuum pumps are respectively fixedly connected to the two exhaust ends of the three-way splitter pipe, and a primary inlet switching valve is fixedly installed at the inlet end of the three-way splitter pipe. The exhaust ends of the two primary centrifugal vacuum pumps are jointly connected... There is a primary exhaust pipe. One end of the primary exhaust pipe is fixedly connected to a manifold exhaust pipe. The exhaust end of the tertiary centrifugal vacuum pump is fixedly connected to the manifold exhaust pipe. The other end of the primary exhaust pipe is fixedly connected to the outer end of the secondary intake pipe. A primary exhaust parallel switching valve is fixedly installed at the outer end of the primary exhaust pipe near the manifold exhaust pipe. A series switching valve is fixedly installed at the outer end of the primary exhaust pipe near the secondary intake pipe. A make-up air pipe is also fixedly connected to the outer end of the primary exhaust pipe. Multiple evenly distributed precision regulating valves are fixedly installed at the outer ends of the inlet pipe and the make-up air pipe. The make-up air pipe is located between the cooler and the series switching valve. The primary exhaust parallel switching valve and the series switching valve are located outside the exhaust ports of the two primary centrifugal vacuum pumps, respectively. Coolers are connected in series on the inlet pipe, the end of the primary exhaust pipe away from the manifold exhaust pipe, and the tertiary intake pipe. A quick shut-off valve is also installed on the manifold exhaust pipe. Buffer tanks are connected in series on the two arms of the three-way splitter pipe near the outer ends of the two primary centrifugal vacuum pumps, the secondary intake pipe near the outer end of the secondary centrifugal vacuum pump, the tertiary intake pipe near the outer end of the tertiary centrifugal vacuum pump, and the manifold exhaust pipe. The buffer tank on the manifold exhaust pipe is located between the end of the dual-flow-channel pressure relief plate and the quick shut-off valve. A stacked pressure relief assembly is fixedly installed inside the buffer tank. The stacked pressure relief assembly includes multiple dual-flow-channel pressure relief plates, multiple conical pressure relief cylinders that are fixedly connected between the air inlet of the buffer tank and the adjacent dual-flow-channel pressure relief plate, and between two adjacent dual-flow-channel pressure relief plates. Multiple connecting blocks are fixedly connected between the outer end of the dual-flow-channel pressure relief plate and the inner wall of the buffer tank.

[0010] Furthermore, the variable frequency unit includes a dual-shaft variable frequency motor, two gearboxes respectively connected to the two output shafts of the dual-shaft variable frequency motor, two primary centrifugal vacuum pumps sharing one variable frequency unit, and a secondary centrifugal vacuum pump and a tertiary centrifugal vacuum pump sharing one variable frequency unit.

[0011] Furthermore, multiple conical pressure relief cylinders and dual-channel pressure relief plates are connected in sequence, and along the direction of air flow, the last dual-channel pressure relief plate is directly opposite the exhaust port of the buffer tank and communicates directly with the inside of the buffer tank.

[0012] Furthermore, the exhaust side of the pressure relief straight hole is connected to the next conical pressure relief cylinder, the exhaust side of the L-shaped exhaust hole is directly connected to the inside of the buffer tank, and a flow-limiting ring is fixedly connected to the end of the dual-channel pressure relief plate near the air inlet side of the buffer tank.

[0013] Furthermore, the dual-channel pressure relief plate is drilled with multiple pressure relief straight holes arranged in a ring array, and the dual-channel pressure relief plate is also drilled with multiple L-shaped exhaust holes arranged in a ring array. The L-shaped exhaust hole array, the pressure relief straight hole array, and the flow limiting ring are all coaxially arranged, and the three are arranged sequentially along the direction away from the axis. The multiple L-shaped exhaust holes and pressure relief straight holes are staggered and distributed.

[0014] Furthermore, the conical pressure relief cylinder includes a conical ring plate fixedly connected to the radial inner wall of the buffer tank or the end face of the dual-flow-channel pressure relief plate facing the air inlet end of the buffer tank, a plurality of split rings arranged in a ring array and slidably connected to the other end face of the dual-flow-channel pressure relief plate, and a plurality of path modification components fixedly connected to the middle of the plurality of split rings respectively. An outer sealing layer is also fixedly connected to the middle of the outer end of the conical ring plate. The outer sealing layer is in contact with the connecting block and the surface of the dual-flow-channel pressure relief plate, and the end of the outer sealing layer away from the conical ring plate crosses the flow-limiting ring and is fixedly connected to the outer wall of the flow-limiting ring. The outer sealing layer is made of a flexible sealing material.

[0015] Optionally, each of the ends of the multiple split rings that are close to each other is chiseled with a receiving groove, and a reset spring is fixedly connected between two adjacent receiving grooves. The reset spring is made of elastic material, and when the two split rings are in contact with each other, the reset spring is in a taut state.

[0016] Furthermore, the path modification component includes a sealing plate and a connecting rod fixedly connected between the sealing plate and the middle of the inner wall of the split ring. When the split ring and the flow-limiting ring are in contact, the sealing plate completely covers the L-shaped exhaust hole.

[0017] 3. Beneficial Effects Compared with the prior art, the advantages of this invention are: (1) By setting up a primary vacuum pump unit that can be connected in parallel or in series, as well as secondary and tertiary centrifugal vacuum pumps, and with multiple switching valves, four time-sharing operation modes are realized: primary unit operating alone, secondary and tertiary unit operating alone, parallel and series connection, etc. This enables the system to cover an ultra-wide operating range from low vacuum and high flow rate to high vacuum and low flow rate, significantly expanding the stable operating range and increasing surge margin.

[0018] (2) In addition, by setting buffer tanks containing stacked pressure relief components at each key pipeline node and setting precision regulating valves in the intake pipeline, pressure relief or air replenishment can be adaptively performed when the mode is switched or the airflow changes suddenly, effectively suppressing the pressure fluctuation peak and overcoming the problems of "air grabbing" and transient pressure shock, thereby ensuring the efficiency and stability of the system in ultra-wide operating conditions and long-term time-varying operating conditions. Attached Figure Description

[0019] Figure 1 This is a right-side perspective view of the present invention; Figure 2 This is a left-side perspective view of the present invention; Figure 3 This is a perspective view of the primary vacuum pump unit of the present invention; Figure 4 This is a perspective view of the two-stage centrifugal vacuum pump and the three-stage centrifugal vacuum pump of the present invention; Figure 5 This is a schematic diagram of the first-stage vacuum pump unit of the present invention operating independently; Figure 6 This is a schematic diagram of the two-stage and three-stage centrifugal vacuum pumps of the present invention operating independently; Figure 7 This is a schematic diagram of the first-stage vacuum pump unit and the second and third-stage centrifugal vacuum pumps operating in parallel according to the present invention; Figure 8 This is a schematic diagram of the first-stage vacuum pump unit and the second and third-stage centrifugal vacuum pumps of the present invention operating in series. Figure 9 This is a perspective view of the invention with the buffer tank installed. Figure 10 This is a top view of the present invention when the buffer tank is installed; Figure 11 This is a perspective view of the invention with the buffer tank installed. Figure 12 This is a front cross-sectional view of the buffer tank of the present invention during depressurization; Figure 13 This is a schematic diagram of the radial cross-section of the buffer tank of the present invention; Figure 14 This is a schematic diagram of the radial cross-section of the buffer tank of the present invention during depressurization; Figure 15 This is a diagram showing the changes in the conical pressure relief cylinder of the present invention during the pressure stabilization process.

[0020] Explanation of the labels in the diagram: 101 Inlet pipe, 102 Primary intake pipe, 103 Three-way branch pipe, 104 Primary exhaust pipe, 105 Secondary intake pipe, 106 Tertiary intake pipe, 107 Tertiary exhaust pipe, 108 Manifold exhaust pipe, 109 Make-up air pipe, 21 Primary centrifugal vacuum pump, 22 Dual-shaft variable frequency motor, 23 Gearbox, 3 Cooler, 41 Secondary centrifugal vacuum pump, 42 Tertiary centrifugal vacuum pump, 501 Primary inlet switching valve, 502 Primary exhaust parallel switching valve, 503 Series switching valve, 504 Front parallel switching valve; 6. Buffer tank, 7. Dual-channel pressure relief plate, 71. Connecting block, 72. Flow limiting ring, 701. L-shaped exhaust hole, 702. Pressure relief straight hole, 8. Conical pressure relief cylinder, 81. Split ring, 821. Sealing plate, 822. Connecting rod, 83. Conical ring plate, 84. Outer sealing layer, 85. Reset spring. Detailed Implementation

[0021] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0022] Example 1: Please see Figures 1-2 A multi-stage time-sharing series-parallel centrifugal vacuum pump system with ultra-wide operating conditions includes an inlet pipe 101, a first-stage inlet pipe 102 fixedly connected to the inlet pipe 101, a three-way diverter pipe 103 fixedly connected to the middle of the first-stage inlet pipe 102, a first-stage vacuum pump unit connected to the three-way diverter pipe 103, a second-stage centrifugal vacuum pump 41, a third-stage centrifugal vacuum pump 42, and two variable frequency drives, such as... Figures 3-4 A three-stage intake pipe 106 is fixedly connected between the exhaust end of the two-stage centrifugal vacuum pump 41 and the intake end of the three-stage centrifugal vacuum pump 42. The first-stage vacuum pump unit includes two first-stage centrifugal vacuum pumps 21. The frequency converter unit includes a dual-shaft frequency converter motor 22 and two gearboxes 23 respectively connected to the two output shafts of the dual-shaft frequency converter motor 22. The two first-stage centrifugal vacuum pumps 21 share one frequency converter unit, and the two-stage centrifugal vacuum pumps 41 and the three-stage centrifugal vacuum pump 42 share one frequency converter unit.

[0023] A secondary intake pipe 105 is fixedly connected between the end of the primary intake pipe 102 and the intake port of the secondary centrifugal vacuum pump, and a pre-connected parallel switching valve 504 is installed at the connection point. The intake ports of the two primary centrifugal vacuum pumps 21 are respectively fixedly connected to the two exhaust ends of the three-way diverter pipe 103, and a primary inlet switching valve 501 is fixedly installed at the intake end of the three-way diverter pipe 103. The exhaust ends of the two primary centrifugal vacuum pumps 21 are jointly fixedly connected to a primary exhaust pipe 104, and a manifold is fixedly connected to one end of the primary exhaust pipe 104. The exhaust pipe 108 is connected to the manifold exhaust pipe 107 via a three-stage exhaust pipe 108. The other end of the first-stage exhaust pipe 104 is fixedly connected to and communicates with the outer end of the second-stage intake pipe 105. A first-stage exhaust parallel switching valve 502 is fixedly installed on the outer end of the first-stage exhaust pipe 104 near the manifold exhaust pipe 108. A series switching valve 503 is fixedly installed on the outer end of the first-stage exhaust pipe 104 near the second-stage intake pipe 105. A makeup air pipe 109 is also fixedly connected to the outer end of the first-stage exhaust pipe 104. 09 is located between the series switching valve 503 and the cooler 3. Multiple evenly distributed precision regulating valves are fixedly installed at the outer ends of both the inlet pipe 101 and the make-up air pipe 109. When a sudden drop in air pressure occurs in this system, the precision regulating valves at the inlet pipe 101 and the make-up air pipe 109 can be opened to make up for the pressure drop, thereby reducing the lower limit of air pressure fluctuations during actual operation and improving stability. The make-up air pipe 109 is located between the cooler 3 and the series switching valve 503, and the first-stage exhaust is connected in parallel. The switching valve 502 and the series switching valve 503 are located outside the exhaust ports of the two first-stage centrifugal vacuum pumps 21, respectively. Coolers 3 are connected in series on the inlet pipe 101, the end of the first-stage exhaust pipe 104 away from the manifold exhaust pipe 108, and the third-stage inlet pipe 106. The coolers 3 can pre-cool the inlet gas of each stage centrifugal vacuum pump so that the gas temperature will not be too high when it enters the first-stage centrifugal vacuum pump 21, the second-stage centrifugal vacuum pump 41, or the third-stage centrifugal vacuum pump 42. A quick shut-off valve is also installed on the manifold exhaust pipe 108. This system has several different operating modes, as detailed below: like Figure 5 When the primary vacuum pump unit is being debugged and operated independently, the system controls the primary inlet switching valve 501 and the primary exhaust parallel switching valve 502 to open, and controls the series switching valve 503 and the pre-parallel switching valve 504 to close, so that the incoming flow passes through the primary inlet switching valve 501 and the three-way diverter 103 to reach the two primary centrifugal vacuum pumps 21. Then the exhaust from the two primary centrifugal vacuum pumps 21 merges in the primary exhaust pipe 104 and passes through the primary exhaust parallel switching valve 502 to reach the confluence exhaust pipe 108 for discharge. like Figure 6When the second and third stage centrifugal vacuum pumps are being debugged and run separately, the system controls the first stage inlet switching valve 501, the first stage exhaust parallel switching valve 502, and the series switching valve 503 to all close, and controls the front parallel switching valve 504 to open. The incoming flow comes from the inlet pipe 101 and the first stage inlet pipe 102, passes through the front parallel switching valve 504 and directly reaches the second stage inlet pipe 105 and enters the second stage centrifugal vacuum pump 41. Then it enters the third stage centrifugal vacuum pump 42 through the third stage inlet pipe 106, and then reaches the manifold exhaust pipe 108 through the third stage exhaust pipe 107 and is discharged. like Figure 7 When the primary vacuum pump unit and the secondary and tertiary centrifugal vacuum pumps are connected in parallel, the system controls the opening of the primary inlet switching valve 501, the primary exhaust parallel switching valve 502, and the pre-parallel switching valve 504, and controls the closing of the series switching valve 503, so that... Figure 5 and Figure 6 The two gas paths shown are parallel; like Figure 8 When the primary vacuum pump unit and the secondary and tertiary centrifugal vacuum pumps are connected in series, the system controls the opening of the primary inlet switching valve 501 and the series switching valve 503, and controls the closing of the primary exhaust parallel switching valve 502 and the pre-parallel switching valve 504. This allows the incoming flow to first enter the primary vacuum pump unit through the primary inlet switching valve 501 and the three-way diverter pipe 103, then converge into the primary exhaust pipe 104, and then directly reach the secondary centrifugal vacuum pump through the series switching valve 503 and the secondary intake pipe 105. After that, it enters the tertiary centrifugal vacuum pump 42 through the tertiary intake pipe 106, and then reaches the confluence exhaust pipe 108 through the tertiary exhaust pipe 107 and is discharged.

[0024] Additionally, it is worth noting that when the system is performing evacuation to maintain a vacuum environment, no gas replenishment is required, and multiple precision regulating valves are kept closed during this time. However, when switching between series and parallel operation modes, the system pressure will fluctuate, and multiple precision regulating valves will be kept open to replenish gas in a timely manner if the pressure is insufficient.

[0025] In summary, in the aforementioned ultra-wide operating condition multi-stage time-sharing series-parallel centrifugal vacuum pump system, the multi-stage time-sharing series-parallel centrifugal vacuum pump configuration allows for different operating modes, thus covering a wider range of operating conditions and increasing surge margin. Combined with the precision regulating valve, it enables gas replenishment operations based on system conditions, reducing the adverse effects of gas competition. Furthermore, by pre-calculating the operating range of different modes, planning operating strategies, and pre-writing them into the control system, it is possible to control the first-stage inlet switching valve 501, the first-stage exhaust parallel switching valve 502, the series switching valve 503, and the pre-parallel switching valve 504 to be in different states under different operating conditions. This achieves time-sharing series-parallel control of the first-stage vacuum pump unit and the second and third-stage centrifugal vacuum pumps, effectively reducing system control complexity. The modular design of the unit facilitates transportation, installation, and maintenance.

[0026] Example 2: like Figures 9-10 Buffer tanks 6 are connected in series on the two arms of the three-way diverter 103 near the outer ends of the two primary centrifugal vacuum pumps 21, the secondary intake pipe 105 near the outer end of the secondary centrifugal vacuum pump 41, the tertiary intake pipe 106 near the outer end of the tertiary centrifugal vacuum pump 42, and the manifold exhaust pipe 108. The buffer tank 6 on the manifold exhaust pipe 108 is located between the end of the dual-flow-channel pressure relief plate 7 and the quick-closing valve. Figure 11 The buffer tank 6 is equipped with a stacked pressure relief assembly, which includes multiple dual-channel pressure relief plates 7 and multiple conical pressure relief cylinders 8 that are fixedly connected between the air inlet of the buffer tank 6 and the adjacent dual-channel pressure relief plates 7, as well as between two adjacent dual-channel pressure relief plates 7. Multiple connecting blocks 71 are fixedly connected between the outer end of the dual-channel pressure relief plate 7 and the inner wall of the buffer tank 6. The multiple conical pressure relief cylinders 8 and the dual-channel pressure relief plates 7 are connected in sequence and along the direction of air flow. The last dual-channel pressure relief plate 7 is directly opposite the exhaust port of the buffer tank 6 and is directly connected to the inside of the buffer tank 6. When the gas pressure is too high, it is discharged from the last dual-channel pressure relief plate 7 after being relieved by all the dual-channel pressure relief plates 7 and conical pressure relief cylinders 8 in the buffer tank 6. It can be discharged directly into the buffer tank 6 and then discharged from the buffer tank 6.

[0027] like Figure 11 and Figure 13The dual-channel pressure relief plate 7 has multiple pressure relief straight holes 702 arranged in a ring array. It also has multiple L-shaped exhaust holes 701 arranged in a ring array. The L-shaped exhaust hole array 701, the pressure relief straight hole array 702, and the flow-limiting ring 72 are all coaxially arranged and sequentially arranged along a direction away from the axis. The multiple L-shaped exhaust holes 701 and pressure relief straight holes 702 are staggered. The exhaust side opening of the pressure relief straight hole 702 communicates with the next conical pressure relief cylinder 8. The exhaust side opening of the L-shaped exhaust hole 701 directly communicates with the interior of the buffer tank 6. The dual-channel pressure relief plate 7 is located near the air inlet side of the buffer tank 6. One end is also fixedly connected to a flow-limiting ring 72. The conical pressure relief cylinder 8 includes a conical ring plate 83 fixedly connected to the radial inner wall of the buffer tank 6 or the end face of the dual-channel pressure relief plate 7 facing the air inlet end of the buffer tank 6, a plurality of split rings 81 arranged in a ring array and slidably connected to the other end face of the dual-channel pressure relief plate 7, and a plurality of path modification components fixedly connected to the middle of the plurality of split rings 81 respectively. The path modification components include a sealing plate 821 and a connecting rod 822 fixedly connected between the sealing plate 821 and the middle of the inner wall of the split rings 81. When the split rings 81 abut against the flow-limiting ring 72, the sealing plate 821 completely covers the L-shaped exhaust hole 701, such as Figure 13 When the air pressure is too low to push the conical pressure relief cylinder 8 to expand, it does not need to be depressurized. The gas can be directly discharged into the buffer tank 6 through the L-shaped exhaust hole 701, and then continue to be discharged outwards, such as... Figure 14 When the gas pressure is too high and needs to be released, the gas pressure will push the end of the small diameter of the conical pressure relief cylinder 8 to expand until it flips over the pressure relief straight hole 702, so that the gas in the conical pressure relief cylinder 8 can flow through the pressure relief straight hole 702 to the next conical pressure relief cylinder 8 to continue to release pressure, thus achieving adaptive pressure relief.

[0028] An outer sealing layer 84 is fixedly connected to the middle of the outer end of the conical ring plate 83. The outer sealing layer 84 is in contact with the surface of the connecting block 71 and the dual-channel pressure relief plate 7. The end of the outer sealing layer 84 away from the conical ring plate 83 crosses the flow-limiting ring 72 and is fixedly connected to the outer wall of the flow-limiting ring 72. The outer sealing layer 84 is made of flexible sealing material. The outer sealing layer 84 can effectively seal the gap at the connection between the dual-channel pressure relief plate 7 and the conical pressure relief cylinder 8, so that the gas is not easy to leak directly into the buffer tank 6 along the gap between the two before the pressure is released. This effectively avoids the impact of this unreleased gas on the stability of the system.

[0029] Multiple split rings 81 have receiving grooves cut into their close-to-each ends. A reset spring strip 85 is fixedly connected between two adjacent receiving grooves. The reset spring strip 85 is made of elastic material, and when two split rings 81 are in contact with each other, the reset spring strip 85 is in a taut state. By setting the reset spring strip 85, after the pressure is released, its deformation recovery function can assist the reset of the conical ring plate 83, which is convenient for the next series-parallel switching.

[0030] like Figure 12 When the gas pressure is high, after the gas enters the conical pressure relief cylinder 8, under the action of gas pressure, it can push the conical pressure relief cylinder 8 from the inside out, causing its inner diameter to gradually expand towards the outlet of the dual-channel pressure relief plate 7. On the one hand, this can consume a certain amount of gas pressure; on the other hand, such as... Figure 14 During its expansion process, the path modification component will move accordingly, thereby gradually blocking the opening of the L-shaped vent 701, such as... Figure 12 and 15 This forces the gas to exit only from the pressure relief hole 702 into the next conical pressure relief cylinder 8, and then perform another pressure relief. After one or more pressure reliefs, if the pressure is insufficient to allow the next conical pressure relief cylinder 8 to fully expand again, and the path modification component cannot cover or fully cover the L-shaped exhaust hole 701, the gas will be directly discharged from the L-shaped exhaust hole 701 into the buffer tank 6, and then discharged along the discharge end of the buffer tank 6.

[0031] By installing buffer tanks 6 containing stacked pressure relief components at each key pipeline node and precision regulating valves on the inlet pipe 101 and the secondary air intake pipe, the system can adaptively relieve pressure or replenish air when switching modes or experiencing sudden changes in airflow. This effectively suppresses pressure fluctuation peaks, overcomes the problems of "air grabbing" and transient pressure shocks, and ensures the system's high efficiency and stability in ultra-wide operating conditions and long-term time-varying operating conditions.

[0032] The above description is merely a preferred embodiment of the present invention; it encompasses all the protection scope of the present invention. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solutions and improved concepts of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A multi-stage time-sharing centrifugal vacuum pump system with ultra-wide operating conditions, comprising an inlet pipe (101), a first-stage inlet pipe (102) fixedly connected to the inlet pipe (101), a three-way diverter pipe (103) fixedly connected to the middle of the first-stage inlet pipe (102), a first-stage vacuum pump unit, a second-stage centrifugal vacuum pump (41), a third-stage centrifugal vacuum pump (42), and two frequency converters connected to the three-way diverter pipe (103), wherein a third-stage inlet pipe (106) is fixedly connected between the exhaust end of the second-stage centrifugal vacuum pump (41) and the inlet end of the third-stage centrifugal vacuum pump (42), characterized in that: The primary vacuum pump unit includes two primary centrifugal vacuum pumps (21). A secondary intake pipe (105) is fixedly connected between the end of the primary intake pipe (102) and the intake port of the secondary centrifugal vacuum pump (41), and a front-mounted parallel switching valve (504) is installed at the connection point. The intake ports of the two primary centrifugal vacuum pumps (21) are respectively fixedly connected to the two exhaust ends of a three-way diverter pipe (103), and a primary inlet switching valve (501) is fixedly installed at the intake end of the three-way diverter pipe (103). The exhaust ends of the two primary centrifugal vacuum pumps (21) are jointly fixedly connected to a primary exhaust pipe (104). One end of the primary exhaust pipe (104) is fixedly connected to a manifold exhaust pipe (108). A tertiary exhaust pipe (107) is fixedly connected between the exhaust end of the tertiary centrifugal vacuum pump (42) and the manifold exhaust pipe (108). The other end of the primary exhaust pipe (104) is fixedly connected to and communicates with the outer end of the secondary intake pipe (105). A primary exhaust parallel switching valve (502) is fixedly installed at the outer end of the primary exhaust pipe (104) near the confluence exhaust pipe (108). A series switching valve (503) is fixedly installed at the outer end of the primary exhaust pipe (104) near the secondary intake pipe (105). A make-up air pipe (109) is also fixedly connected to the outer end of the primary exhaust pipe (104). Multiple evenly distributed precision regulating valves are fixedly installed at the outer ends of both the incoming pipe (101) and the make-up air pipe (109). (109) is located between the cooler (3) and the series switching valve (503), and the first-stage exhaust parallel switching valve (502) and the series switching valve (503) are located outside the exhaust ports of the two first-stage centrifugal vacuum pumps (21), and the cooler (3) is connected in series on the end of the inlet pipe (101), the first-stage exhaust pipe (104) away from the confluence exhaust pipe (108) and the third-stage intake pipe (106). A quick shut-off valve is also installed on the confluence exhaust pipe (108). The two arms of the three-way diverter (103) near the outer ends of the two primary centrifugal vacuum pumps (21), the secondary intake pipe (105) near the outer end of the secondary centrifugal vacuum pump (41), the tertiary intake pipe (106) near the outer end of the tertiary centrifugal vacuum pump (42), and the manifold exhaust pipe (108) are all connected in series with buffer tanks (6). The buffer tank (6) on the manifold exhaust pipe (108) is located between the end of the dual-channel pressure relief plate (7) and the quick shut-off valve. The buffer tank (6) is fixedly installed with a stacked pressure relief assembly inside. The stacked pressure relief assembly includes multiple dual-channel pressure relief plates (7), multiple conical pressure relief cylinders (8) respectively fixedly connected between the air inlet of the buffer tank (6) and the adjacent dual-channel pressure relief plate (7), and between two adjacent dual-channel pressure relief plates (7). Multiple connecting blocks (71) are fixedly connected between the outer end of the dual-channel pressure relief plate (7) and the inner wall of the buffer tank (6).

2. The ultra-wide operating condition multi-stage time-sharing series-parallel centrifugal vacuum pump system according to claim 1, characterized in that: The variable frequency unit includes a dual-shaft variable frequency motor (22), two gearboxes (23) respectively connected to the two output shafts of the dual-shaft variable frequency motor (22), two primary centrifugal vacuum pumps (21) share one variable frequency unit, and the secondary centrifugal vacuum pump (41) and the tertiary centrifugal vacuum pump (42) share one variable frequency unit.

3. The ultra-wide operating condition multi-stage time-sharing series-parallel centrifugal vacuum pump system according to claim 2, characterized in that: Multiple conical pressure relief cylinders (8) and dual-channel pressure relief plates (7) are connected in sequence and along the direction of air flow. The last dual-channel pressure relief plate (7) is directly opposite the exhaust port of the buffer tank (6) and is directly connected to the inside of the buffer tank (6).

4. The ultra-wide operating condition multi-stage time-sharing series-parallel centrifugal vacuum pump system according to claim 3, characterized in that: The dual-channel pressure relief plate (7) has multiple pressure relief straight holes (702) arranged in a ring array. The dual-channel pressure relief plate (7) also has multiple L-shaped exhaust holes (701) arranged in a ring array. The exhaust side opening of the pressure relief straight hole (702) is connected to the next conical pressure relief cylinder (8). The exhaust side opening of the L-shaped exhaust hole (701) is directly connected to the inside of the buffer tank (6). The dual-channel pressure relief plate (7) is also fixedly connected to the air inlet side of the buffer tank (6) with a flow limiting ring (72).

5. A multi-stage time-sharing centrifugal vacuum pump system with ultra-wide operating conditions according to claim 4, characterized in that: The L-shaped exhaust port (701) array, the pressure relief straight hole (702) array, and the flow limiting ring (72) are all coaxially arranged, and the three are arranged sequentially along the direction away from the axis. Multiple L-shaped exhaust ports (701) and pressure relief straight holes (702) are distributed in an alternating manner.

6. The ultra-wide operating condition multi-stage time-sharing series-parallel centrifugal vacuum pump system according to claim 5, characterized in that: The conical pressure relief cylinder (8) includes a conical ring plate (83) fixedly connected to the radial inner wall of the buffer tank (6) or the side face of the dual-channel pressure relief plate (7) facing the air inlet end of the buffer tank (6), a plurality of split rings (81) arranged in a ring array and slidably connected to the other end face of the dual-channel pressure relief plate (7), and a plurality of path modification components fixedly connected to the middle of the plurality of split rings (81). The outer end of the conical ring plate (83) is also fixedly connected to an outer sealing layer (84). The outer sealing layer (84) is in contact with the surface of the connecting block (71) and the dual-channel pressure relief plate (7), and the end of the outer sealing layer (84) away from the conical ring plate (83) crosses the flow limiting ring (72) and is fixedly connected to the outer wall of the flow limiting ring (72). The outer sealing layer (84) is made of a flexible sealing material.

7. A multi-stage time-sharing centrifugal vacuum pump system with ultra-wide operating conditions according to claim 6, characterized in that: Each of the multiple split rings (81) has a receiving groove at its close end. A reset spring strip (85) is fixedly connected between two adjacent receiving grooves. The reset spring strip (85) is made of elastic material, and when the two split rings (81) are in contact with each other, the reset spring strip (85) is in a taut state.

8. A multi-stage time-sharing centrifugal vacuum pump system with ultra-wide operating conditions according to claim 7, characterized in that: The path modification component includes a sealing plate (821) and a connecting rod (822) fixedly connected between the sealing plate (821) and the middle of the inner wall of the split ring (81). When the split ring (81) abuts against the flow limiting ring (72), the sealing plate (821) completely covers the L-shaped exhaust hole (701).

Images