A centrifugal vacuum pump unit for high flow rate and low pressure

Abstract

The present invention relates to a centrifugal vacuum pump group for large flow and low pressure applied to the technical field related to vacuum pumps. It adopts a three-stage series arrangement to obtain a high compression ratio, which can meet the target requirement of lower absolute pressure, and the first-stage vacuum pump adopts double-sided air intake, which can meet the target requirement of large flow; in addition, the compressed gas is cooled by spray cooling in the internal circulation, thereby replacing the heat exchanger cooling in the prior art, effectively reducing the floor space of the vacuum pump group, and the structure is compact and the cost is lower; in addition, during the internal circulation cooling process, it can automatically perform adaptive deformation according to the temperature of the gas. When the gas temperature is high, it can automatically stretch, and then form a plurality of cooling plates spaced apart from each other in the water-cooling cylinder, so that the contact range with the gas is greatly improved, so that the heat of the gas can be quickly taken away when passing through the water-cooling cylinder, thereby achieving cooling.

Description

Technical Field

[0001] The present invention relates to a centrifugal vacuum pump group for large flow and low pressure, and in particular to a centrifugal vacuum pump group for large flow and low pressure applied in the technical field related to vacuum pumps. Background Art

[0002] A vacuum pump is a device or equipment that uses mechanical, physical, chemical or physicochemical methods to evacuate the container to create a vacuum.

[0003] Under the working conditions of low target absolute pressure and large flow, the operating performance of the existing centrifugal vacuum pump system is not ideal. The efficiency and stability of the pump are easily affected, and the required pressure ratio and flow requirements cannot be met. In addition, the air heats up seriously during vacuum compression.

[0004] In order to solve the problem of gas heating caused by compression, existing technologies such as the dual-pump vacuum pump unit disclosed in Chinese patent CN104595160A and the Roots water ring vacuum pump unit disclosed in Chinese patent CN115853773A often separately set up a heat exchanger to cool the compressed air. This method leads to higher design and manufacturing costs of the vacuum pump unit and increases the overall investment of the system. Summary of the Invention

[0005] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that the existing vacuum pumps are difficult to meet the pressure ratio and flow requirements, and the design cost is relatively high.

[0006] In order to solve the above problems, the present invention provides a centrifugal vacuum pump group for large flow and low pressure, comprising a motor, a speed-increasing gearbox connected to the motor drive shaft, and a multi-stage compression unit connected to two output shafts of the speed-increasing gearbox respectively. The air inlet sides of the two multi-stage compression units are fixedly connected with a Y-shaped air guide pipe, the air inlet end of the Y-shaped air guide pipe is fixedly connected with an air guide main pipe, the air inlet end of the air guide main pipe is fixedly connected with a pre-cooling heat exchanger, the exhaust sides of the two multi-stage compression units are fixedly connected with an inverted Y-shaped air collecting pipe, the upper end of the inverted Y-shaped air collecting pipe is fixedly connected with a muffler, and the multi-stage compression The unit includes a second-stage and third-stage vacuum pump and a first-stage vacuum pump connected in series. The output shaft of the speed-increasing gearbox is connected to the second-stage and third-stage vacuum pumps and the first-stage vacuum pump in sequence through a coupling. The second-stage and third-stage vacuum pumps include a main outer cover shell and a sub-outer cover shell connected by bolts, and the upper ends of the main outer cover shell and the sub-outer cover shell are fixedly connected to an exhaust pipe and an air intake pipe respectively. Spray ports are opened at the upper and lower ends of the main outer cover shell near the sub-outer cover shell. A cooling gap is formed between the main outer cover shell and the sub-outer cover shell, and a sealing sheet is sealed and fixed between the inner ring edge of the impeller side, and the spray port is connected to the cooling gap.

[0007] The first-stage vacuum pump includes two back-to-back double-sided air intake vacuum pump units. The air intakes of the two vacuum pump units are fixedly connected to an F-shaped double-port air intake pipe. The ends of the two first-stage vacuum pumps that are away from each other are both provided with a collecting exhaust port.

[0008] The upper end of the collecting exhaust port is fixedly connected to a water-cooling cylinder, and an inverted U-shaped tube is fixedly connected between the upper end of the water-cooling cylinder and the air inlet pipe mouth on the same side. The water-cooling cylinder has a double-layer structure, and a water-cooling cavity is formed between the double layers of the water-cooling cylinder. The outer end of the water-cooling cylinder is fixedly connected to two water inlets and two drain outlets, and the two water inlets and two drain outlets are all connected to the water-cooling cavity.

[0009] In the above-mentioned centrifugal vacuum pump group for large flow and low pressure, a three-stage series arrangement is adopted to obtain a high compression ratio, which can meet the target lower absolute pressure requirement, and a dual-head scheme is adopted in parallel arrangement to obtain a large suction flow, and the first-stage vacuum pump adopts double-sided air intake, which can meet the target large flow requirement; in addition, the temperature is reduced by the internal circulation spray cooling method, which effectively reduces the space occupied by the vacuum pump group compared with the heat exchanger, and has a compact structure and lower cost.

[0010] As a further improvement of the present application, the two water inlets are coaxial, the two drain outlets are coaxial, and the two axes are perpendicular to each other.

[0011] As another improvement of the present application, two shunt pipes are provided inside the water-cooling chamber, which are centrally symmetrical about the axis of the water-cooling cylinder. A plurality of evenly distributed cooling fins are fixedly connected to the inner wall of the water-cooling cylinder. The plurality of cooling fins are divided into two groups, and the two groups of cooling fins are respectively connected to the two shunt pipes. The inner layer of the water-cooling cylinder is provided with a plurality of water inlet holes corresponding to the plurality of cooling fins.

[0012] As another improved supplement to the present application, the diversion pipeline includes a semi-ring liquid guide pipe fixed and connected to the drain outlet and a plurality of return pipes fixedly connected to the outer end of the semi-ring liquid guide pipe. The plurality of return pipes respectively pass through a plurality of water inlet holes and are connected to a plurality of cooling fins.

[0013] As another improved supplement of the present application, the cooling plate includes a hemispherical water collecting cover and a gap heat exchange plate fixedly connected to the outer end of the hemispherical water collecting cover, and two adjacent gap heat exchange plates are overlapped with each other.

[0014] As another improved supplement to the present application, the gap heat exchange plate includes an outer envelope and an inner isolation layer fixedly connected to the middle part of the hemispherical water collecting cover. The inner isolation layer is located on the inner side of the outer envelope, and the end of the inner isolation layer away from the hemispherical water collecting cover does not contact the inner wall of the end of the outer envelope, and the inner isolation layer divides the interior of the outer envelope into two interconnected transfer cavities. Two water outlets are opened on the hemispherical water collecting cover, and the return pipe is fixed to the edge of one of the water outlets.

[0015] As another improved supplement of the present application, the outer covering layer includes an outer carrier sheet and a plurality of lining bones fixedly embedded in the inner wall of the outer carrier sheet. The plurality of lining bones are in a wavy shape, the outer carrier sheet is in a wrinkled state, and the inner isolation layer is an arc-shaped structure.

[0016] As another improved supplement of the present application, the lining bone and the inner isolation layer are both made of a two-way shape memory alloy material, and after the temperature exceeds the critical temperature, the lining bone and the inner isolation layer are both in a flat state.

[0017] In summary, a three-stage series arrangement is adopted to obtain a high compression ratio, which can meet the target lower absolute pressure requirement, and a dual-head parallel arrangement is adopted to obtain a large suction flow, and the first-stage vacuum pump adopts double-sided air intake, which can meet the target large flow requirement; in addition, the compressed gas is cooled by the internal circulation spray cooling method, thereby replacing the heat exchanger cooling in the existing technology, effectively reducing the footprint of the vacuum pump group, and the structure is compact and the cost is lower; in addition, during the internal circulation cooling process, it can automatically perform adaptive deformation according to the temperature of the gas. When the gas temperature is high, it can automatically stretch, and then form a plurality of mutually spaced cooling plates in the water-cooling cylinder, so that the contact range with the gas is greatly improved, so that when the gas passes through the water-cooling cylinder, the heat can be quickly taken away, thereby achieving cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a perspective view of the first embodiment of the present application;

[0019] Figure 2 A three-stage cascade vacuum pump portion according to a first embodiment of the present application;

[0020] Figure 3 A top view of a three-stage series vacuum pump portion of the first embodiment of the present application;

[0021] Figure 4 A perspective view of a two-stage and three-stage vacuum pump according to a first embodiment of the present application;

[0022] Figure 5 A perspective view of a first-stage vacuum pump according to a first embodiment of the present application;

[0023] Figure 6 This is a radial cross-sectional view of the water-cooling cylinder portion of the first embodiment of the present application;

[0024] Figure 7 A three-dimensional diagram of the water-cooling cylinder portion of the first embodiment of the present application;

[0025] Figure 8 This is a radial cross-sectional view of the water-cooling cylinder portion of the second embodiment of the present application;

[0026] Figure 9 This is a schematic diagram of a diversion pipeline according to a second embodiment of the present application;

[0027] Figure 10 This is a cross-sectional schematic diagram of a cooling fin according to a second embodiment of the present application;

[0028] Figure 11 This is a schematic cross-sectional view of the cooling fin portion of the second embodiment of the present application;

[0029] Figure 12 This is a radial cross-sectional view of the water-cooling cylinder portion when the gas temperature is high in the second embodiment of the present application.

[0030] Description of the numbers in the figure:

[0031] 1 Motor, 2 Speed increasing gearbox, 3 Second and third stage vacuum pump, 301 Inlet pipe, 302 Exhaust pipe, 303 Inverted Y-shaped collecting pipe, 304 Muffler, 31 Main outer cover, 32 Secondary outer cover, 33 Sealing plate, 4 First stage vacuum pump, 401 F-shaped double-port inlet pipe, 402 Collecting exhaust port, 51 Air guide main pipe, 52 Y-shaped air guide pipe, 53 Inverted U-shaped pipe, 6 Pre-cooling heat exchanger, 7 Water cooling cylinder, 701 Water inlet, 702 Drain port, 703 Semi-ring liquid guide pipe, 704 Return water pipe, 705 Water inlet hole, 8 Hemispherical water collecting cover, 9 Gap heat exchanger, 91 Outer cladding, 92 Inner isolation layer, 911 Outer carrier sheet, 912 Inner lining bone. DETAILED DESCRIPTION

[0032] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0033] The first implementation method:

[0034] Figure 1-3 A centrifugal vacuum pump group for large flow and low pressure is shown, comprising a motor 1, a speed-increasing gearbox 2 connected to the drive shaft of the motor 1, and a multi-stage compression unit respectively connected to the two output shafts of the speed-increasing gearbox 2. The air inlet sides of the two multi-stage compression units are fixedly connected to a Y-shaped air duct 52, the air inlet end of the Y-shaped air duct 52 is fixedly connected to an air guide pipe 51, and the air inlet end of the air guide pipe 51 is fixedly connected to a pre-cooling heat exchanger 6. The exhaust sides of the two multi-stage compression units are fixedly connected to an inverted Y-shaped air collecting pipe 303, and the upper end of the inverted Y-shaped air collecting pipe 303 is fixedly connected to a muffler 304. The multi-stage compression unit comprises a second and third stage vacuum pump 3 and a first stage vacuum pump 4 connected in series. The output shaft of the speed-increasing gearbox 2 is sequentially connected to the second and third stage vacuum pump 3 and the first stage vacuum pump 4 through a coupling, as shown in FIG. Figure 5 The first-stage vacuum pump 4 includes two vacuum pump units with double-sided air intakes, and the air intakes of the two vacuum pump units are fixedly connected to an F-shaped double-port air intake pipe 401. The ends of the two first-stage vacuum pumps 4 that are away from each other are both provided with a collecting exhaust port 402. Figure 3 When in use, after the centrifugal vacuum pump group absorbs the gas, it first passes through the pre-cooling heat exchanger 6 to cool the air flow to a predetermined temperature below 40°C, and then enters the two multi-stage compression units with back-to-back double-sided air intake under the diversion effect of the Y-shaped air guide pipe 52, and first passes through the F-shaped double-port air intake pipe 401 for double-sided air intake into the first-stage vacuum pump 4. After being compressed separately by the two vacuum pump units with back-to-back double-sided air intake, it is collected at the collecting exhaust port 402, and enters the second and third-stage vacuum pumps 3 along the water-cooling cylinder 7 and the inverted U-shaped pipe 53. After the secondary compression and tertiary compression of the two impellers connected in series in the second and third-stage vacuum pumps 3, it is discharged along the exhaust pipe 302, and under the action of the inverted Y-shaped gas collecting pipe 303, the two paths of gas obtained through the third-stage compression are introduced into the muffler 304 for silencing and discharge.

[0035] In the above process, two sets of multi-stage compression units can simultaneously compress the air three times, and intake air from both sides, thereby meeting the requirements of large flow and high compression ratio.

[0036] like Figure 6-7 , c in the figure represents a water-cooling cavity, the upper end of the collecting and exhausting port 402 is fixedly connected to a water-cooling cylinder 7, the upper end of the water-cooling cylinder 7 and the inlet pipe 301 on the same side are fixedly connected with an inverted U-shaped tube 53, the water-cooling cylinder 7 is a double-layer structure, and a water-cooling cavity is formed between the double layers of the water-cooling cylinder 7, the outer end of the water-cooling cylinder 7 is fixedly connected to two water inlets 701 and two drain ports 702, the two water inlets 701 and the two drain ports 702 are both connected to the water-cooling cavity, the two water inlets 701 are coaxial, the two drain ports 702 are coaxial, and the two axes are perpendicular to each other, at the inlet of the water-cooling cylinder 7 The water inlet 701 can be connected to an external cooling water connection, so that the cooling water is circulated into the water-cooling chamber through the two water inlets 701 and discharged from the two drain outlets 702, so that the water-cooling cylinder 7 is in a low-temperature state. When the gas is compressed at the first-stage vacuum pump 4, the temperature rises. When the gas moves to the second and third-stage vacuum pumps 3, it will pass through the water-cooling cylinder 7 and the circulating low-temperature cooling water will carry a lot of heat, thereby achieving cooling of the gas. Compared with setting up a heat exchanger separately, this cooling setting can effectively reduce the space occupied by the vacuum pump, has a compact structure, and can effectively reduce the setting cost.

[0037] The secondary and tertiary vacuum pump 3 includes a main outer cover shell 31 and a secondary outer cover shell 32 connected by bolts, and the upper ends of the main outer cover shell 31 and the secondary outer cover shell 32 are fixedly connected with an exhaust pipe 302 and an air inlet pipe 301 respectively. Spray ports are opened at the upper and lower ends of the main outer cover shell 31 near the secondary outer cover shell 32. A cooling gap is formed between the main outer cover shell 31 and the secondary outer cover shell 32, and a sealing plate 33 is sealed and fixed between the inner ring edge of the two near the impeller side. The sealing plate 33 is used to protect the impeller so that the cooling water does not easily penetrate into the internal impeller after entering the cooling gap. At the same time, the sealing plate 33 keeps the cooling gap sealed, which is convenient for stable cooling. The spray port is connected to the cooling gap, such as Figure 4 In the figure, a represents the impeller and b represents the spray port. The spray port can be connected to cooling water. When in use, the cooling water can fill the cooling gap, so that the heat generated by the gas during compression can be immediately taken away by the cooling water, thereby effectively reducing the temperature of the gas after compression, achieving the effect of cooling while compressing. Compared with the existing technology, it further reduces the demand for heat exchangers caused by cooling after the air is heated.

[0038] Among them, the second and third stage vacuum pumps 3 are set up with two impellers connected in series. An impeller is set on the side close to the air inlet pipe 301, and an impeller is also set on the side close to the exhaust pipe 302. Therefore, when the gas passes through the interior of the second and third stage vacuum pumps 3 from the air inlet pipe 301 and is discharged from the exhaust pipe 302, double compression can be achieved.

[0039] In the above-mentioned centrifugal vacuum pump group for large flow and low pressure, a three-stage series arrangement is adopted to obtain a high compression ratio, which can meet the target lower absolute pressure requirement, and a dual-head scheme is adopted in parallel arrangement to obtain a large suction flow, and the first-stage vacuum pump 4 adopts a double-sided air intake, which can meet the target large flow requirement; in addition, the temperature is reduced by the internal circulation spray cooling method, which effectively reduces the space occupied by the vacuum pump group compared with the heat exchanger, and has a compact structure and lower cost.

[0040] Second implementation method:

[0041] Based on the first embodiment, this embodiment adds a plurality of cooling fins and related structures, and the rest of the structure remains the same as the first embodiment.

[0042] Figure 8-9As shown, two shunt pipes are provided inside the water-cooling chamber, which are centrally symmetrical about the axis of the water-cooling cylinder 7. A plurality of evenly distributed cooling fins are fixedly connected to the inner wall of the water-cooling cylinder 7. The plurality of cooling fins are divided into two groups, and the two groups of cooling fins are respectively connected to the two shunt pipes. The inner layer of the water-cooling cylinder 7 is provided with a plurality of water inlet holes 705 corresponding to the plurality of cooling fins. The shunt pipe includes a semi-circular liquid guide pipe 703 fixed and connected to the drain port 702, and a plurality of return pipes 703 fixedly connected to the outer end of the semi-circular liquid guide pipe 703. 04. Multiple return water pipes 704 respectively pass through multiple water inlet holes 705 and are connected to multiple cooling fins. When cooling is performed, the cooling water enters the water-cooling chamber along the water inlet 701, and then directly enters the multiple cooling fins along the multiple water inlet holes 705 and circulates once in the cooling fins. Then, the cooling water is gathered into the semi-annular liquid guide pipe 703 along the multiple return water pipes 704 and discharged along the drain port 702, thereby realizing the diversion of cooling water inlet and drainage, thereby effectively ensuring the circulating cooling effect of the compressed air.

[0043] like Figure 9-10 The cooling plate includes a hemispherical water collecting cover 8 and a gap heat exchange plate 9 fixedly connected to the outer end of the hemispherical water collecting cover 8. Two adjacent gap heat exchange plates 9 overlap each other. The gap heat exchange plate 9 includes an outer cover 91 fixedly connected to the middle part of the hemispherical water collecting cover 8 and an inner isolation layer 92. The inner isolation layer 92 is located on the inner side of the outer cover 91, and the end of the inner isolation layer 92 away from the hemispherical water collecting cover 8 does not contact the inner wall of the end of the outer cover 91, and the inner isolation layer 92 divides the interior of the outer cover 91 into two mutually connected transfer chambers. Two water outlets are opened on the hemispherical water collecting cover 8, and the return pipe 704 is fixed to the edge of one of the water outlets. The cooling water enters the transfer chamber inside the gap heat exchange plate 9 along the exposed water outlet, bypasses the inner isolation layer 92 and enters the other transfer chamber, and then returns to the return pipe 704 and is discharged, thereby realizing the circulation of cooling water in the gap heat exchange plate 9.

[0044] like Figure 11 The outer cladding 91 includes an outer carrier sheet 911 and a plurality of lining bones 912 fixedly embedded in the inner wall of the outer carrier sheet 911. The plurality of lining bones 912 are in a wavy shape, the outer carrier sheet 911 is in a wrinkled state, the inner isolation layer 92 is an arc-shaped structure, and the lining bones 912 and the inner isolation layer 92 are both made of a two-way shape memory alloy material, such as Figure 12 , and above the critical temperature, the lining bone 912 and the inner isolation layer 92 are in a straight state. When the compressed air temperature is low, multiple gap heat exchange fins 9 are in a mutually overlapping and wrinkled state. At this time, they are mainly concentrated near the inner wall of the water-cooling cylinder 7. When the gas passes through the water-cooling cylinder 7, it shuttles through multiple gap heat exchange fins 9 and performs heat exchange. Figure 12When the temperature is higher than the critical temperature of the inner lining bone 912 and the inner isolation layer 92, the two will be straightened, thereby causing the gap heat exchange plate 9 to expand toward the inside of the water-cooling cylinder 7, and at the same time causing the outer carrier plate 911 to gradually flatten, that is, increasing the distribution range of the multiple gap heat exchange plates 9, and also increasing the surface area of the gap heat exchange plates 9 that directly contact the air, thereby greatly improving the heat exchange speed with the compressed air and making the heat exchange effect better.

[0045] It is worth noting that, in specific implementation, the two-way shape memory alloy material can be selected according to actual needs to select a memory alloy material with a suitable critical temperature.

[0046] In summary, a three-stage series arrangement is adopted to obtain a high compression ratio, which can meet the target lower absolute pressure requirement, and a dual-head parallel arrangement is adopted to obtain a large suction flow, and the first-stage vacuum pump 4 adopts a double-sided air intake, which can meet the target large flow requirement; in addition, the compressed gas is cooled by the internal circulation spray cooling method, thereby replacing the heat exchanger cooling in the prior art, effectively reducing the floor space of the vacuum pump group, and the structure is compact and the cost is lower; in addition, during the internal circulation cooling process, it can automatically perform adaptive deformation according to the temperature of the gas. When the gas temperature is high, it can automatically stretch, and then form a plurality of mutually spaced cooling plates in the water-cooled cylinder 7, so that the contact range with the gas is greatly improved, so that when the gas passes through the water-cooled cylinder 7, the heat can be quickly taken away, thereby achieving cooling.

[0047] In view of current actual needs, the protection scope of the above-mentioned implementation mode adopted in this application is not limited to this. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. A centrifugal vacuum pump unit for high flow and low pressure, characterized by: The invention comprises a motor (1), a speed-increasing gearbox (2) connected to a drive shaft of the motor (1), and a multistage compression unit respectively connected to two output shafts of the speed-increasing gearbox (2); the air inlet sides of the two multistage compression units are fixedly connected to a Y-shaped air guide pipe (52); the air inlet end of the Y-shaped air guide pipe (52) is fixedly connected to an air guide main pipe (51); the air inlet end of the air guide main pipe (51) is fixedly connected to a precooling heat exchanger (6); the exhaust sides of the two multistage compression units are fixedly connected to an inverted Y-shaped air collecting pipe (303); the upper end of the inverted Y-shaped air collecting pipe (303) is fixedly connected to a muffler (304); the multistage compression unit comprises a second-stage vacuum pump (3) and a third-stage vacuum pump (3) connected in series with each other, and a first-stage vacuum pump (5). (4), the output shaft of the speed increasing gearbox (2) is connected to the second and third stage vacuum pumps (3) and the first stage vacuum pump (4) in sequence through a coupling, the second and third stage vacuum pumps (3) include a main outer cover shell (31) and a sub-outer cover shell (32) connected by bolts, and the upper ends of the main outer cover shell (31) and the sub-outer cover shell (32) are fixedly connected with an exhaust pipe (302) and an air inlet pipe (301), respectively, and the main outer cover shell (31) is provided with spray ports at both upper and lower ends near the sub-outer cover shell (32), a cooling gap is formed between the main outer cover shell (31) and the sub-outer cover shell (32), and a sealing sheet (33) is sealed and fixed between the inner ring edge of the impeller side and the two, and the spray port is communicated with the cooling gap; The primary vacuum pump (4) comprises two vacuum pump units with double-sided air intakes, the air intakes of the two vacuum pump units being fixedly connected to an F-shaped double-port air intake pipe (401), and the ends of the two primary vacuum pumps (4) that are away from each other are each provided with a collecting exhaust port (402); The upper end of the collecting exhaust port (402) is fixedly connected to a water-cooling cylinder (7), and an inverted U-shaped tube (53) is fixedly connected between the upper end of the water-cooling cylinder (7) and the mouth of the air inlet pipe (301) on the same side. The water-cooling cylinder (7) is a double-layer structure, and a water-cooling cavity is formed between the double layers of the water-cooling cylinder (7). The outer end of the water-cooling cylinder (7) is fixedly connected to two water inlets (701) and two drain ports (702). The two water inlets (701) and the two drain ports (702) are both in communication with the water-cooling cavity. The two water inlets (701) are coaxial, the two drain ports (702) are coaxial, and the two axes are perpendicular to each other. Two shunt pipes are provided inside the water-cooling cavity and are centrally symmetrical about the axis of the water-cooling cylinder (7); a plurality of evenly distributed cooling fins are fixedly connected to the inner wall of the water-cooling cylinder (7); the plurality of cooling fins are divided into two groups, and the two groups of cooling fins are respectively connected to the two shunt pipes; the inner layer of the water-cooling cylinder (7) is provided with a plurality of water inlet holes (705) corresponding to the plurality of cooling fins; the shunt pipe includes a semi-circular liquid guide pipe (703) fixed and communicated with the drain port (702) and a plurality of return pipes (704) fixedly connected to the outer end of the semi-circular liquid guide pipe (703); the plurality of return pipes (704) respectively pass through the plurality of water inlet holes (705) and are connected to the plurality of cooling fins; the cooling fin includes a hemispherical water collecting cover (8) and a gap heat exchange plate (9) fixedly connected to the outer end of the hemispherical water collecting cover (8); two adjacent gap heat exchange plates (9) are overlapped with each other; The gap heat exchange plate (9) includes an outer cladding (91) fixedly connected to the middle of the hemispherical water collecting cover (8) and an inner isolation layer (92), the inner isolation layer (92) is located on the inner side of the outer cladding (91), and the end of the inner isolation layer (92) away from the hemispherical water collecting cover (8) does not contact the inner wall of the end of the outer cladding (91), and the inner isolation layer (92) divides the interior of the outer cladding (91) into two mutually connected transfer cavities, the hemispherical water collecting cover (8) is opened with two water outlets, and the return pipe (704) is fixed to the edge of one of the water outlets.

2. A centrifugal vacuum pump assembly for large flow and low pressure according to claim 1, characterized in that: The outer cladding (91) comprises an outer carrier sheet (911) and a plurality of lining bones (912) fixedly embedded in the inner wall of the outer carrier sheet (911); the plurality of lining bones (912) are in a wavy shape, the outer carrier sheet (911) is in a wrinkled state, and the inner isolation layer (92) is an arc-shaped structure.

3. A centrifugal vacuum pump assembly for large flow and low pressure according to claim 2, characterized in that: The inner lining bone (912) and the inner isolation layer (92) are both made of a two-way shape memory alloy material, and after the temperature exceeds a critical temperature, the inner lining bone (912) and the inner isolation layer (92) are both in a straight state.

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