Two-stage vacuum pump

Abstract

The utility model relates to a two-stage vacuum pump, which belongs to the technical field of vacuum pumps and comprises a pump body, a front end cover and a rear end cover are respectively arranged at the front end and the rear end of the pump body, a pair of rotors is arranged in the pump body, and a pair of gears meshed with each other are arranged in the front end cover. One rotor extends to the outer side of the front end cover and is connected with a motor output shaft coupling; the pump body comprises a first-stage pump body and a second-stage pump body, the first-stage pump body and the second-stage pump body are respectively provided with an air inlet and an air outlet, the air outlet of the first-stage pump body and the air inlet of the second-stage pump body are respectively used for being connected with a heat exchanger, a separation cavity is arranged in the second-stage pump body, and a communicating pipe is arranged between the separation cavity and the air return port end of the first-stage pump body. In the embodiment of the utility model, the communicating pipe is arranged between the first-stage pump body and the second-stage pump body and is used for returning air of the second-stage pump body to cool the first-stage pump area, so that the volume of a pump set cooling system is saved, the structure is simple, and the manufacturing cost is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of vacuum pumps, and in particular relates to a double-stage vacuum pump. Background Art

[0002] The function of Roots vacuum pump is to discharge air or other gases in closed containers and closed systems to achieve a certain vacuum. It is widely used in traditional industries, food and light industries. The air-cooled Roots vacuum pump is based on the ordinary Roots vacuum pump with a bypass gas cooling system. The external cooler allows the gas to automatically circulate and cool the rotor and pump body. The cooling gas enters the suction chamber of the pump from both sides of the pump body, so that the pump will not be overheated due to compressed gas, so that it can operate reliably for a long time under high pressure difference and high compression ratio. In the prior art, the external cooler usually uses a heat exchanger. The pump body of the multi-stage Roots vacuum pump needs to be equipped with a heat exchanger cooling system, which occupies a large space and has a high manufacturing cost. Utility Model Content

[0003] In order to overcome the defects of the prior art, the purpose of the utility model is to provide a two-stage vacuum pump for solving the technical problem of inconvenience in use in the prior art.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] The cam is provided with a pair of gears which are meshed with each other and are connected with the front and rear ends of the pump respectively.

[0006] According to the above technical solution, it is further preferred that the connecting pipes are in two groups, which are respectively arranged on both sides of the pump body.

[0007] Preferably, a plurality of heat sinks are provided on the pump body.

[0008] Preferably, a grease cavity filled with grease is provided in the rear end cover for providing lubrication to the bearing.

[0009] Preferably, a lubricating oil cavity filled with lubricating oil is provided in the front end cover for providing lubrication for the bearings and gears.

[0010] Preferably, supports are fixedly provided on the front end cover and the rear end cover respectively.

[0011] Preferably, the impeller is provided with an anti-corrosion coating, and the anti-corrosion coating is made of titanium alloy or ceramic polymer material.

[0012] Preferably, the impeller is a two-blade involute impeller or a three-blade involute impeller.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1. The utility model provides a two-stage vacuum pump. In the embodiment of the utility model, a connecting pipe is provided between the primary pump body and the secondary pump body, which is used to return the air in the compartment of the secondary pump body to cool the primary pump body, thereby saving the volume of the return air pipeline of the pump group cooling system, having a simple structure and low manufacturing cost.

[0015] 2. The utility model provides a two-stage vacuum pump. The impeller of the utility model is provided with an anti-corrosion layer, which can make the rotating impeller have better corrosion resistance and effectively extend its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the utility model device;

[0017] Figure 2 A schematic diagram of the longitudinal cross-sectional structure of the pump body of the utility model device;

[0018] Figure 3 This is a schematic diagram of the transverse cross-sectional structure of the pump body of the utility model.

[0019] In the figure: 1, pump body, 2, front cover, 3, rear cover, 4, rotor, 5, gear, 6, air inlet, 7, air outlet, 8, impeller, 17, heat sink, 18, support, 19, primary pump body, 20, secondary pump body, 21, partition, 22, connecting pipe, 23, compartment. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0021] Embodiment 1

[0022] like Figure 1 to Figure 3As shown, the utility model provides a two-stage vacuum pump, including a pump body 1, the pump body 1 includes a primary pump body 19 and a secondary pump body 20, the primary pump body 19 is provided with a front end cover 2 at the end, the secondary pump body 20 is provided with a rear end cover 3 at the end, the primary pump body 19 and the secondary pump body 20 are respectively sealed and fixedly connected with the front end cover 2 and the rear end cover 3 on both sides, and a spacer 21 is provided between the primary pump body 19 and the secondary pump body 20, which is used to separate the primary pump body 19 and the secondary pump body 20 to form two independent pump chambers. The primary pump body 19 and the secondary pump body 20 are respectively provided with an air inlet 6 and an air outlet 7. A pair of rotors 4 are provided in the pump body 1, and the two ends of the rotor 4 are respectively connected to the front cover 2 and the rear cover 3 with bearings. A pair of gears 5 meshing with each other are provided in the front cover 2, and the gears 5 are respectively fixedly connected to the rotors 4. The two rotors 4 are driven by two groups of gears 5 meshing with each other and rotate in opposite directions at the same speed. One of the rotors 4 extends to the outside of the front cover 2 and is connected to the motor output shaft coupling. An impeller 8 is fixedly provided on the rotor 4. When the two groups of rotors 4 rotate, they respectively drive the two groups of impellers 8 to rotate. The air is compressed between the adjacent impeller 8 blades to compress the air sucked into the air inlet 6 and discharge it from the air outlet 7. A connecting pipe 22 is fixedly arranged between the primary pump body 19 and the secondary pump body 20, and a partition cavity 23 is arranged in the secondary pump body 20. One end of the connecting pipe 22 is connected with the partition cavity 23, and the other end of the connecting pipe 22 is connected with the return air port end of the primary pump body 19. The air outlet 7 of the primary pump body 19 and the air inlet of the secondary pump body 20 are used to connect the heat exchanger. The compressed gas extracted from the primary pump body 19 is cooled by the cooling heat exchanger and then connected with the air inlet 6 of the secondary pump body 20 for secondary compression of the compressed air, and the cooled compressed air is sucked into the secondary pump body 20 at the same time. The gas outlet 7 of the primary pump body is connected to the gas input end of the heat exchanger through a pipeline. The heat exchanger adopts a water-cooling method. The heat exchanger is respectively provided with a cooling water inlet and a cooling water outlet for heat exchange cooling of the compressed air. The gas output end of the heat exchanger is respectively connected to the pump cavity through a pipeline. The connecting pipe 22 is respectively used to connect the compartment 23 of the primary pump body 19 and the secondary pump body 20. After the compressed air cooled by the heat exchanger enters the secondary pump body 20, most of the gas is discharged from the gas outlet 7 of the secondary pump body 20 after the secondary compression of the secondary pump body 20, and a small amount of gas is discharged from the gas outlet 7 of the secondary pump body 20. Part of the gas is connected with the connecting pipe 22 through the partition cavity 23 and enters the pump cavity return air port of the primary pump body 19. The connecting pipe 22 can be provided to use a small part of the cooling gas entering the secondary pump body 20 as return air to the primary pump body 19 to cool the primary pump body 19. In this way, the primary pump body and the rotor are cooled through the partition cavity 23 and the connecting pipe 22 of the secondary pump body 20 and the return air port of the primary pump body 19, thereby saving return air lines and pipelines, reducing the occupied space of the cooling system structure, and reducing the manufacturing cost of the cooling system.

[0023] As an improved embodiment of the utility model, the pump body 1 is divided into multiple groups, and the multiple groups of pump bodies 1 are interconnected in sequence to form multiple groups of multi-stage vacuum pump groups. The air outlet end of the previous stage pump body is respectively connected to the air inlet end of the next stage pump body. A heat exchanger can be added between each group of pump bodies, and a plurality of heat exchangers can be arranged between each group of pump bodies to cool the pump bodies. In this way, the need for multi-stage cascade vacuum extraction can be realized, and the purpose of fully cooling the multi-stage vacuum pump group can be met, thereby reducing the occupied volume of the vacuum pump unit, saving the cost of investing in multiple groups of heat exchangers, and having strong practicality.

[0024] In order to better cool the two-stage pump body, the connecting pipes 22 are divided into two groups, which are respectively arranged on both sides of the pump body 1.

[0025] The rear end cover 3 is provided with a grease cavity filled with grease for providing lubrication to the bearing.

[0026] The front end cover 2 is provided with a lubricating oil cavity filled with lubricating oil for providing lubrication for bearings and gears.

[0027] The pump body 1 is provided with a plurality of heat sinks 17. The heat sinks 17 can be used to cool the pump body 1 externally.

[0028] The front end cover 2 and the rear end cover 3 are respectively provided with a first cooling chamber and a second cooling chamber. The first cooling chamber is abuttedly connected to the front end cover 2, and the second cooling chamber is abuttedly connected to the rear end cover 3. The first cooling chamber and the second cooling chamber are connected through a pipeline. In an embodiment of the utility model, the first cooling chamber and the second cooling chamber are connected by a pipeline, and liquid coolant is arranged inside for cooling the pump body. The coolant can be water-cooled or oil-cooled.

[0029] Supports 18 are respectively fixedly provided on the front end cover 2 and the rear end cover 3 for fixing.

[0030] The impeller 8 is a two-blade involute impeller or a three-blade involute impeller. A vacuum pump with a suitable number of blades is selected according to the suction efficiency and exhaust capacity of the Roots pump. An anti-corrosion coating is provided on the impeller 8. The anti-corrosion coating is provided on the impeller 8, which can adapt to the application environment of vacuum pumps in multiple scenarios, especially suitable for environments with corrosive acidic gases. To avoid corrosion of the rotor impeller and affect the vacuum degree of the vacuum pump, the anti-corrosion coating is made of titanium alloy or ceramic polymer material. When making the coating, the anti-corrosion coating and the impeller 8 can be made by gluing or by electroplating. In the utility model, the rotor material can be cast iron infiltrated with Hastelloy alloy rotors and spiral blades, which have better corrosion resistance, effectively improve the rigidity of the rotor and spiral blades, and extend their service life.

[0031] Of course, the above embodiments are not intended to limit the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A two-stage vacuum pump, comprising a pump body (1), characterized in that: The pump body (1) is provided with a front cover (2) and a rear cover (3) at the front and rear ends respectively. A pair of rotors (4) are provided in the pump body (1). The two ends of the rotors (4) are respectively connected to the bearings of the front cover (2) and the rear cover (3). The front cover (2) is provided with a pair of gears (5) that are meshed with each other. The gears (5) are respectively fixedly connected to the rotors (4). One of the rotors (4) extends to the outside of the front cover (2) and is connected to the motor output shaft coupling. The pump body (1) comprises a primary pump body (19) and a secondary pump body (20). The primary pump body (19) and the secondary pump body (20) are respectively connected to the front cover (2) and the rear cover (3) at both sides. The cover (3) is sealed and fixedly connected, a partition cavity (23) is arranged in the secondary pump body (20), an air inlet (6) and an air outlet (7) are respectively arranged on the primary pump body (19) and the secondary pump body (20), the air outlet (7) of the primary pump body (19) and the air inlet (6) of the secondary pump body (20) are respectively used to connect to a heat exchanger, and a connecting pipe (22) is arranged between the primary pump body (19) and the secondary pump body (20); one end of the connecting pipe (22) is connected to the partition cavity (23), and the other end of the connecting pipe (22) is connected to the return air port of the primary pump body (19); an impeller (8) is fixedly arranged on the rotor (4).

2. A two-stage vacuum pump according to claim 1, characterized in that: The connecting pipes (22) are in two groups and are respectively arranged on both sides of the pump body (1).

3. A two-stage vacuum pump according to claim 1, characterized in that: The pump body (1) is provided with a plurality of cooling fins (17).

4. A two-stage vacuum pump according to claim 1, characterized in that: The rear end cover (3) is provided with a grease cavity filled with grease for providing lubrication for the bearing.

5. A two-stage vacuum pump according to claim 1, characterized in that: A lubricating oil cavity filled with lubricating oil is arranged inside the front end cover (2) and is used to provide lubrication for bearings and gears.

6. A two-stage vacuum pump according to claim 1, characterized in that: Supports (18) are fixedly arranged on the front end cover (2) and the rear end cover (3), respectively.

7. A two-stage vacuum pump according to claim 1, characterized in that: The impeller (8) is provided with an anti-corrosion coating, and the anti-corrosion coating is made of a titanium alloy material or a ceramic polymer material.

8. A two-stage vacuum pump according to claim 7, characterized in that: The impeller (8) is a two-blade involute impeller or a three-blade involute impeller.

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