A stainless steel roots vacuum pump

Abstract

The utility model relates to a kind of stainless steel roots vacuum pumps, including stainless steel pump body, the front and rear of stainless steel pump body are equipped with first cooling water spacer sleeve, first cooling water spacer sleeve is respectively equipped in front end cover and rear end cover, cooling water spacer cavity is formed between the front and rear end cover of front end cover, between the front and rear end cover of rear end cover;Second cooling water spacer sleeve is equipped in stainless steel pump body, cooling water spacer cavity is formed between stainless steel rotor and stainless steel pump body;Two groups of end cap dynamic sealing components are equipped in front end cover, two groups of end cap dynamic sealing components are equipped in rear end cover;The out shaft end of main shaft is provided with out shaft end mechanical sealing component.The utility model uses stainless steel welded pump body to replace traditional cast pump body, combined with composite sealing system and integrated cooling structure, significantly improve corrosion resistance, sealing reliability and temperature rise control ability, suitable for suction delivery corrosive, high temperature and contain dust gas, manufacturing cost is reduced, service life is extended.

Description

Technical Field

[0001] This utility model relates to the field of Roots vacuum pump technology, and in particular to a stainless steel Roots vacuum pump, which is especially suitable for pumping and conveying corrosive, high-temperature and dusty gases in industrial scenarios, such as chemical, pharmaceutical, new energy and lithium battery manufacturing fields. Background Technology

[0002] Roots pumps are positive displacement pumps that achieve gas compression or vacuum suction through a pair of meshing rotors, and are widely used in industrial gas transportation. The main components of traditional Roots pumps (such as the pump body, end covers, and rotors) are mostly made of cast iron or carbon steel, and the sealing system relies on labyrinth piston ring seals and skeleton oil seals. Existing technology has the following drawbacks:

[0003] (1) Insufficient corrosion resistance of materials: Cast iron and carbon steel are easily corroded by corrosive gases, resulting in short pump life and high maintenance costs;

[0004] (2) Poor sealing reliability: Labyrinth seals and skeleton oil seals are prone to failure in high temperature or corrosive media, resulting in lubricating oil contamination or gas leakage;

[0005] (3) Casting process limitations: Stainless steel casting is difficult and has problems such as cold shuts, hot cracks, and compositional segregation, resulting in low yield and high cost;

[0006] (4) Insufficient temperature rise control: Traditional pump bodies lack efficient cooling systems, and the rotor temperature rises significantly under high pressure differential conditions, which can easily lead to thermal deformation and jamming.

[0007] Some existing technologies propose using ceramic coatings to improve the corrosion resistance of Roots pumps, but this does not address the overall corrosion resistance of the material. Other solutions using a split-type cast stainless steel pump body do not optimize the sealing structure and still rely on complex casting processes. Therefore, existing technologies have not yet achieved a comprehensive solution that optimizes both low-cost processing of stainless steel materials and the synergistic optimization of sealing and cooling. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a stainless steel Roots vacuum pump, which is based on stainless steel welded parts, a composite sealing system and an integrated cooling structure, thereby improving corrosion resistance, reducing manufacturing costs and enhancing operational stability.

[0009] The purpose of this utility model is achieved as follows:

[0010] A stainless steel Roots vacuum pump includes a stainless steel pump body, with a front end cover at the front end and a rear end cover at the rear end. The pump body has an air inlet at the upper end and an air outlet at the lower end, thereby forming the suction and exhaust chamber of the Roots pump. Inside the stainless steel pump body, a pair of figure-eight shaped stainless steel rotors are arranged horizontally in parallel, with one of the active stainless steel rotors sleeved on a main shaft, which is located inside the stainless steel pump body.

[0011] The front end cover includes two end covers arranged in parallel front and rear, with a ring connecting the two end covers. The ring is fitted onto the main shaft. The end cover closer to the stainless steel pump body is connected to the stainless steel pump body. The structure of the rear end cover is the same as that of the front end cover. The front end cover and the rear end cover are symmetrically arranged at the front and rear ends of the stainless steel pump body. The front end cover is provided with a lubricating oil tank, and the rear end cover is provided with a gearbox.

[0012] The front end of the main shaft extends out of the lubricating oil tank and is connected to the coupling, which is connected to the motor.

[0013] The stainless steel pump body is provided with a first cooling water baffle at the front and rear, respectively. The front end cover is provided with a first cooling water baffle inside the ring and the rear end cover is provided with a first cooling water baffle outside the ring. Cooling water cavities are formed between the front and rear end covers of the front end cover and between the front and rear end covers of the rear end cover. The stainless steel pump body is provided with a second cooling water baffle. The second cooling water baffle is provided outside the stainless steel rotor. Cooling water cavities are formed between the stainless steel rotor and the stainless steel pump body.

[0014] The front cover is provided with two sets of end cover dynamic sealing assemblies, and the rear cover is provided with two sets of end cover dynamic sealing assemblies. The end cover dynamic sealing assemblies are respectively arranged between the annulus of the front cover and the rear cover and the main shaft.

[0015] The output end of the main shaft is provided with an output end mechanical seal assembly, which includes a rotating ring assembly and a stationary ring assembly. The rotating ring assembly includes a rotating ring, a rotating ring seat, a stainless steel spring, and a rotating ring seal ring. The stationary ring assembly includes a stationary ring, a stationary ring seat, and a stationary ring seal ring. The rotating ring seat, rotating ring, stationary ring, and stationary ring seat are sequentially sleeved on the output end of the main shaft. The rotating ring is provided on the rotating ring seat, and the stationary ring is provided on the stationary ring seat. The rotating ring is located on the side close to the stainless steel pump body.

[0016] Furthermore, the lubricating oil tank is fixedly connected to the front side of the front end cover with hexagon socket screws, and the gearbox is fixedly connected to the rear side of the rear end cover with hexagon socket screws; the front end of the front end cover is provided with a bearing, and the rear end of the rear end cover is also provided with a bearing, which is sleeved on the main shaft.

[0017] Furthermore, the motor is connected to the lubricating oil tank via a motor connecting bracket, which is located outside the coupling.

[0018] Furthermore, the gearbox is equipped with a synchronizing gear, which is sleeved on the end of the main shaft.

[0019] Furthermore, the cooling water inside the stainless steel pump body and the cooling water inside the end cover are interconnected through stainless steel pipes to form the cooling system of the Roots pump.

[0020] Furthermore, the end cover dynamic sealing assembly includes a skeleton oil seal, a ceramic bushing, piston rings, piston ring seats, an oil baffle, a sealing bushing, and an O-ring. The ceramic bushing, oil baffle, and piston ring seat 12.4 are sequentially fitted onto the main shaft, with the piston ring seat located on the side closest to the stainless steel pump body. The piston ring seat has multiple piston rings, and a sealing bushing is provided on the outer side of the piston ring seat. A skeleton oil seal is provided between the ceramic bushing and the outer end cover.

[0021] Furthermore, an O-ring is provided between the ceramic bushing and the oil baffle.

[0022] Furthermore, multiple sets of stainless steel springs are provided between the moving ring and the moving ring seat, and a moving ring sealing ring is provided inside the moving ring seat; a stationary ring sealing ring is provided between the stationary ring seat and the lubricating oil tank.

[0023] Furthermore, the moving ring is a graphite sealing ring, and the moving ring seat is a stainless steel support.

[0024] Furthermore, the stationary ring is a hard alloy sealing ring, and the stationary ring seat is a cast iron stationary ring seat.

[0025] Compared with the prior art, the beneficial effects of this utility model are:

[0026] This utility model provides a stainless steel Roots vacuum pump. By replacing the traditional cast pump body with a stainless steel welded pump body, combined with a composite sealing system and integrated cooling structure, it significantly improves corrosion resistance, sealing reliability, and temperature rise control capability. It is suitable for pumping and conveying corrosive, high-temperature, and dust-containing gases, reducing manufacturing costs and extending service life. It can meet the stringent operating conditions of the chemical, pharmaceutical, and new energy industries. It has the following advantages:

[0027] (1) Significantly improved corrosion resistance: All stainless steel welded parts are resistant to acid, alkali and organic solvent corrosion, and the service life is greatly extended compared with traditional cast iron pumps;

[0028] (2) Reduced manufacturing costs: By replacing the traditional cast pump body with a stainless steel welded pump body, the yield rate is increased to over 95%, and the manufacturing cost is greatly reduced.

[0029] (3) Enhanced sealing reliability: The leakage rate of the composite sealing system is reduced to below 0.1%, and it can withstand high temperature of 150℃ and pressure difference of 10MPa.

[0030] (4) Temperature rise control optimization: The integrated cooling system greatly reduces the rotor temperature rise and avoids rotor rubbing problems caused by thermal deformation;

[0031] (5) Expanded scope of application: It can handle media containing dust, gas-liquid mixtures and highly corrosive media, and is suitable for emerging fields such as lithium battery electrolyte transportation. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of this utility model.

[0033] Figure 2 This is a radial cross-sectional view of the stainless steel pump body of this utility model.

[0034] Figure 3 This is an enlarged schematic diagram of the end cap dynamic sealing assembly of this utility model.

[0035] Figure 4 This is an enlarged schematic diagram of the mechanical seal assembly at the output shaft end of this utility model.

[0036] Figure 5 This is a schematic diagram of the stainless steel pump body of this utility model.

[0037] Figure 6 This is a radial cross-sectional view of the stainless steel pump body of this utility model.

[0038] in:

[0039] 1. Stainless steel pump body, 1.1 air inlet, 1.2 exhaust outlet, 2. front end cover, 3. lubricating oil tank, 4. coupling, 5. rear end cover, 6. gearbox, 7. synchronous gear, 8. first cooling water diaphragm, 9. second cooling water diaphragm, 10. stainless steel rotor, 11. main shaft, 12. end cover dynamic seal assembly, 12.1 skeleton oil seal, 12.2 ceramic bushing, 12.3 piston ring, 12.4 piston ring seat, 12.5 oil baffle, 12.6 sealing bushing, 12.7 O-ring seal, 13. outlet shaft mechanical seal assembly, 13.1 rotating ring, 13.2 rotating ring seat, 13.3 stainless steel spring, 13.4 rotating ring seal, 13.5 stationary ring, 13.6 stationary ring seat, 13.7 stationary ring seal, 14. motor connecting frame, 15. motor. Detailed Implementation

[0040] To better understand the technical solution of this utility model, a detailed description will be provided below in conjunction with relevant illustrations. It should be understood that the specific embodiments described below are not intended to limit the specific implementation of the technical solution of this utility model, but are merely possible implementations of the technical solution of this utility model. It should be noted that the descriptions of the positional relationships of the components herein, such as component A being located above component B, are based on the relative positions of the components in the illustrations and are not intended to limit the actual positional relationships of the components. Example 1

[0041] See Figures 1-4 , Figure 1 A structural schematic diagram of this utility model has been drawn. As shown in the figure, this utility model relates to a stainless steel Roots vacuum pump, which includes a stainless steel pump body 1. The front end of the stainless steel pump body 1 is provided with a front end cover 2, and the rear end is provided with a rear end cover 5. The upper end of the pump body 1 is provided with an air inlet 1.1, and the lower end is provided with an exhaust outlet 1.2, thereby forming the suction and exhaust chamber of the Roots pump.

[0042] A pair of figure-eight shaped stainless steel rotors 10 are arranged horizontally and parallel inside the stainless steel pump body 1, one of which is an active stainless steel rotor 10, which is sleeved on a main shaft 11, which is located inside the stainless steel pump body 1.

[0043] The front end cover 2 includes two end covers arranged in parallel front and rear, with a ring connecting the two end covers. The ring is sleeved on the main shaft 11. The end cover closer to the stainless steel pump body 1 is connected to the stainless steel pump body 1. The structure of the rear end cover 5 is the same as that of the front end cover 2. The front end cover 2 and the rear end cover 5 are symmetrically arranged at the front and rear ends of the stainless steel pump body 1.

[0044] The front cover 2 is provided with a lubricating oil tank 3, which is fixedly connected to the front side of the front cover 2 with hexagon socket screws. The rear cover 5 is provided with a gearbox 6, which is fixedly connected to the rear side of the rear cover 5 with hexagon socket screws. The front end of the front cover 2 is provided with a bearing, and the rear end of the rear cover 5 is also provided with a bearing, which is sleeved on the main shaft 11.

[0045] The front end (outlet end) of the main shaft 11 extends out of the lubricating oil tank 3 and is connected to the coupling 4. The coupling 4 is connected to the motor 15. The motor 15 is connected to the lubricating oil tank 3 through the motor connecting frame 14. The motor connecting frame 14 is located outside the coupling 4. The gearbox 6 is provided with a synchronous gear 7, which is sleeved on the end of the main shaft 11.

[0046] The stainless steel pump body 1 is provided with a first cooling water baffle 8 at the front and rear respectively. The first cooling water baffle 8 is provided inside the ring of the front end cover 2 and outside the ring of the rear end cover 5 respectively, forming a cooling water baffle cavity between the front and rear end covers of the front end cover 2 and between the front and rear end covers of the rear end cover 5.

[0047] The stainless steel pump body 1 is provided with a second cooling water baffle 9, which is located outside the stainless steel rotor 10, forming a cooling water baffle between the stainless steel rotor 10 and the stainless steel pump body 1. This is equivalent to setting a cooling water baffle on the outer ring of the pump body's suction and exhaust chambers, which is used to cool the rotor and the pumped gas inside the pump body. The cooling water inside the pump body and the cooling water in the end cover are connected to each other through stainless steel pipes to form the cooling system of the Roots pump.

[0048] Therefore, a cooling water baffle is set around the outer ring and end cover of the stainless steel pump body, which is connected by stainless steel pipelines to form a circulating cooling channel, reducing the rotor temperature rise to below 80°C; the cooling water baffle also cools the sealing components and bearings, extending the life of the seals.

[0049] The front cover 2 is provided with two sets of end cover dynamic sealing assemblies 12. Similarly, the rear cover 5 is provided with two sets of end cover dynamic sealing assemblies 12. The end cover dynamic sealing assemblies 12 are respectively arranged between the annulus of the front cover 2 and the rear cover 5 and the main shaft 11. These four sets of end cover dynamic sealing assemblies 12 are used to isolate the lubricating oil in the lubricating oil tanks and gearbox at both ends of the Roots pump from the contamination of the pumped chemical gas.

[0050] The end cap dynamic sealing assembly 12 includes a skeleton oil seal 12.1, a ceramic bushing 12.2, a piston ring 12.3, a piston ring seat 12.4, an oil baffle 12.5, a sealing bushing 12.6, and an O-ring 12.7. The ceramic bushing 12.2, the oil baffle 12.5, and the piston ring seat 12.4 are sequentially fitted onto the main shaft 11. The piston ring seat 12.4 is located on the side close to the stainless steel pump body 1. The piston ring seat 12.4 is provided with multiple piston rings 12.3, and the outer side of the piston ring seat 12.4 is provided with a sealing bushing 12.6. The skeleton oil seal 12.1 is provided between the ceramic bushing 12.2 and the outer end cap, and the O-ring 12.7 is provided between the ceramic bushing 12.2 and the oil baffle 12.5, forming a double sealing barrier of labyrinth seal and ceramic bushing.

[0051] The output shaft end of the main shaft 11 is provided with an output shaft end mechanical seal assembly 13, which adopts a balanced mechanical seal. The output shaft end mechanical seal assembly 13 includes a rotating ring assembly and a stationary ring assembly. The rotating ring assembly includes a rotating ring 13.1, a rotating ring seat 13.2, a stainless steel spring 13.3, and a rotating ring sealing ring 13.4. The stationary ring assembly includes a stationary ring 13.5, a stationary ring seat 13.6, and a stationary ring sealing ring 13.7. The rotating ring seat 13.2, rotating ring 13.1, stationary ring 13.5, and stationary ring seat 13.6 are sequentially sleeved on the output shaft end of the main shaft 11. The rotating ring 13.1 is provided on the rotating ring seat 13.2, and the stationary ring 13.5 is provided on the stationary ring seat 13.6. The rotating ring 13.1 is located on the side close to the stainless steel pump body 1.

[0052] Multiple sets of stainless steel springs 13.3 are provided between the moving ring 13.1 and the moving ring seat 13.2, and a moving ring sealing ring 13.4 is provided inside the moving ring seat 13.2; a stationary ring sealing ring 13.7 is provided between the stationary ring seat 13.6 and the lubricating oil tank 3;

[0053] The moving ring 13.1 is a graphite sealing ring, and the moving ring seat 13.2 is a stainless steel support; the stationary ring 13.5 is a hard alloy sealing ring, and the stationary ring seat 13.6 is a cast iron stationary ring seat, which is resistant to high temperature and chemical corrosion.

[0054] See Figures 5-6 , Figure 5 A structural schematic diagram of the stainless steel pump body of this utility model is shown. As shown in the figure, the stainless steel pump body 1 includes a front end cover plate, a rear end cover plate, a left semi-circular pump housing, and a right semi-circular pump housing. Both the left and right semi-circular pump housings are semi-circular annular shells. A front end cover plate is provided at the front end of the left and right semi-circular pump housings, and a rear end cover plate is provided at the rear end of the left and right semi-circular pump housings. Both the front and rear end cover plates are circular end cover plates with figure-eight shaped inner holes. The left and right semi-circular pump housings are symmetrically arranged and their shapes match the figure-eight shaped inner holes of the end cover plates. The front and rear ends of the left and right semi-circular pump housings are respectively attached to the hole walls of the figure-eight shaped inner holes of the front and rear end cover plates, forming the welded pump body of the Roots vacuum pump.

[0055] A transverse reinforcing rib is provided on the central axis of the outer wall of the left semi-circular pump housing, and a transverse reinforcing rib is also provided on the central axis of the outer wall of the right semi-circular pump housing. The two ends of the transverse reinforcing rib are respectively connected to the front end cover plate and the rear end cover plate, and the left semi-circular pump housing, the right semi-circular pump housing and the front and rear end cover plates are welded together.

[0056] A horizontally arranged air intake chamber is provided above the left and right semi-circular pump housings. The bottom surface of the air intake chamber is connected to the left and right semi-circular pump housings. A circular air inlet is provided on the top surface of the air intake chamber, and an air inlet is vertically connected to an air intake pipe. An air intake flange is provided on the top surface of the air intake pipe. Thus, the air intake pipe connects the air intake chamber and the interior of the left and right semi-circular pump housings to form an upper air intake chamber.

[0057] Below the left and right semicircular pump housings, there is a horizontally arranged exhaust chamber shell. The structure of the exhaust chamber shell is the same as that of the intake chamber shell, and it is arranged symmetrically with the intake chamber shell. The bottom surface of the exhaust chamber shell is provided with a circular exhaust port. The intake port is vertically connected to an exhaust pipe. The bottom surface of the exhaust pipe is provided with an exhaust flange. Thus, the exhaust pipe connects the exhaust chamber shell and the interior of the left and right semicircular pump housings to form a lower exhaust chamber.

[0058] The outer walls of the left and right semicircular pump housings are provided with multiple parallel and evenly distributed arc-shaped reinforcing ribs; the lower ends of the left and right semicircular pump housings are respectively provided with two front and rear support legs, which are distributed at the four corners of the bottom of the welded pump body to support the weight of the vacuum pump.

[0059] The air intake chamber shell has a U-shaped groove structure. The U-shaped groove of the air intake chamber shell faces the left semi-circular pump housing and the right semi-circular pump housing. One side of the U-shaped groove is welded to the top surface of the left semi-circular pump housing, and the other side is welded to the top surface of the right semi-circular pump housing.

[0060] The U-shaped groove of the exhaust chamber shell faces the left and right semi-circular pump housings. One side of the U-shaped groove is welded to the bottom surface of the left semi-circular pump housing, and the other side is welded to the bottom surface of the right semi-circular pump housing.

[0061] The arc-shaped reinforcing rib is a 1 / 4 circular stainless steel sheet.

[0062] The inner arc of the arc-shaped reinforcing rib plate is welded tightly to the outer wall of the pump housing, and the end cover plate, the semi-circular pump housing, the inlet and outlet chamber shell and the transverse reinforcing rib are welded together.

[0063] The inner walls of the air intake chamber shell and the exhaust chamber shell are provided with multiple parallel and evenly distributed inner cavity reinforcing ribs.

[0064] The outrigger includes an outrigger side plate, an outrigger rear cover plate, and an outrigger bottom plate. The outrigger rear cover plate is vertically connected between two parallel outrigger side plates, and the outrigger bottom plate is provided at the bottom of the outrigger side plates.

[0065] The intake pipe is connected to the front and rear end cover plates by intake and exhaust reinforcing ribs, and the exhaust pipe is connected to the front and rear end cover plates by intake and exhaust reinforcing ribs.

[0066] The front end cover, rear end cover, left semi-circular pump housing, right semi-circular pump housing, air inlet pipe, air inlet flange, exhaust pipe, exhaust flange, air inlet chamber shell, exhaust chamber shell, support leg, support leg side plate, support leg rear cover plate, support leg bottom plate, arc-shaped reinforcing rib plate, transverse reinforcing rib plate, inner cavity reinforcing rib, and air inlet and exhaust reinforcing rib are all made of stainless steel and are all processed by water jet cutting equipment. They are connected to each other by welding.

[0067] This utility model relates to a stainless steel Roots vacuum pump, the implementation steps of which are as follows:

[0068] 1. Material preparation: Select 304 or 316L stainless steel plates with a thickness of 3-10mm, and cut them into splicing units by CNC.

[0069] 2. Cold pressing: The sheet metal is cold pressed into the preset shape of pump body, end cover and rotor using special molds, with tolerance controlled within ±0.5mm.

[0070] 3. Welding and assembly: Position the splicing units in the welding fixture and use TIG welding for segmented welding, with weld gaps ≤0.2mm.

[0071] 4. Heat treatment: initial heat treatment after welding (hold at 650℃ for 2 hours, furnace cooling to 300℃ and then air cooling); secondary heat treatment after finishing (hold at 400℃ for 1 hour to eliminate residual stress).

[0072] 5. Installation of sealing and cooling systems:

[0073] 5.1 The end cover is equipped with a composite sealing component to ensure that the gap between the ceramic bushing and the spindle is ≤0.05mm;

[0074] 5.2 Connect the cooling water diaphragm to the external circulation pump, with a water flow rate ≥ 20 L / min.

[0075] Working principle:

[0076] This utility model provides a stainless steel Roots vacuum pump, comprising a pump body made of stainless steel welded parts, and a pair of rotors made of stainless steel welded parts disposed within the pump body for pump suction and exhaust. End caps at both ends of the pump body form the pump's suction and exhaust chambers, and lubrication oil tanks are respectively disposed on the outer sides of the end caps. A pair of synchronous gears are disposed within the lubrication oil tank at one end of the pump body, and a mechanical seal for the main shaft outlet is disposed within the lubrication oil tank at the other end. Four dynamic sealing assemblies are disposed within the end caps on both sides of the pump body, and four bearing seats are also disposed within the end caps, each housing ball bearings to support the two rotors within the pump body. The air inlet is located directly above the pump body, and the exhaust port is located directly below the pump body. A fully enclosed cooling water baffle is disposed outside the pump body, which can effectively cool the rotors inside the pump.

[0077] The pair of stainless steel welded rotors installed in the pump body are made of stainless steel plates through CNC cutting, welding, heat treatment, rough machining, heat treatment, and precision machining processes, and must undergo a strict dynamic balance test before assembly.

[0078] The external curved surface profiles of the aforementioned pair of rotors are composed of meshing involutes and circular arcs. This ensures that the curved surfaces of the two rotors maintain a good meshing clearance during operation, preventing backflow of the pumped gas and ensuring that the Roots pump has higher pumping efficiency.

[0079] The internal dynamic seal of the end cover is a composite seal consisting of a skeleton oil seal, a ceramic bushing, a sealing ring, a piston ring, a piston ring sleeve, a sealing ring bushing, and an oil baffle. Its purpose is twofold: first, to better prevent the pumped gas from entering the lubricating oil tanks at both ends of the pump body and contaminating the pump's lubricating oil; and second, to prevent the lubricating oil at both ends of the pump body from entering the pump's suction chamber, thus avoiding contamination of the transported gas by the lubricating oil.

[0080] The end cover is surrounded by a cooling water jacket to cool the seals, bearings, lubricating oil in the lubricating oil tank, synchronous gears, and mechanical seals at the output end of the main shaft.

[0081] This invention utilizes a stainless steel pump body and improves the dynamic seal structure of the end cover and the main shaft extension end of the Roots pump. A cooling water chamber is incorporated into the pump body casing, significantly reducing the temperature of the Roots pump and avoiding various defects of traditional Roots pumps such as temperature rise, jamming, oil leakage, and overload during high-pressure differential operation. This stainless steel Roots pump is particularly suitable for pumping and conveying corrosive gases in industries such as chemical, pharmaceutical, and lithium battery manufacturing.

[0082] This invention follows the compressibility characteristics of gas. It can be used individually or connected in series with each stage of the Roots pump at a certain gas volume ratio, from small to large. When multiple Roots pumps are connected in series to form a pump set, it offers higher delivery pressure differential, greater compression ratio, higher gas delivery efficiency, and larger gas delivery volume compared to using a single Roots pump, further expanding the application range of Roots pumps.

[0083] In summary, this utility model uses a stainless steel pump body, which is suitable for pumping various corrosive chemical gases; the pump body and end cover are all covered by cooling water, resulting in lower temperature rise and longer service life of the seals during operation; it is suitable for high pressure differential operation and has a wider range of applications.

[0084] The above are merely specific application examples of this utility model and do not constitute any limitation on the scope of protection of this utility model. All technical solutions formed by equivalent transformations or equivalent substitutions fall within the scope of protection of this utility model.

Claims

1. A stainless steel Roots vacuum pump, characterized in that: The system includes a stainless steel pump body (1), with a front end cover (2) at the front end and a rear end cover (5) at the rear end. The pump body (1) has an air inlet (1.1) at the upper end and an exhaust outlet (1.2) at the lower end. Inside the stainless steel pump body (1), a pair of figure-eight shaped stainless steel rotors (10) are arranged in parallel in the horizontal direction. One of the active stainless steel rotors (10) is sleeved on a main shaft (11), which is located inside the stainless steel pump body (1). The front end cover (2) includes two end covers arranged in parallel front and rear, with a ring connecting the two end covers. The ring is fitted on the main shaft (11). The end cover closer to the stainless steel pump body (1) is connected to the stainless steel pump body (1). The structure of the rear end cover (5) is the same as that of the front end cover (2). The front end cover (2) and the rear end cover (5) are symmetrically arranged at the front and rear ends of the stainless steel pump body (1). The front end cover (2) is provided with a lubricating oil tank (3), and the rear end cover (5) is provided with a gearbox (6). The front end of the main shaft (11) extends out of the lubricating oil tank (3) and is connected to the coupling (4), which is connected to the motor (15). The stainless steel pump body (1) is provided with a first cooling water baffle (8) at the front and rear respectively. The first cooling water baffle (8) is provided inside the ring of the front end cover (2) and outside the ring of the rear end cover (5). Cooling water baffles are formed between the front and rear end covers of the front end cover (2) and between the front and rear end covers of the rear end cover (5). The stainless steel pump body (1) is provided with a second cooling water baffle (9). The second cooling water baffle (9) is provided outside the stainless steel rotor (10). Cooling water baffles are formed between the stainless steel rotor (10) and the stainless steel pump body (1). The front cover (2) is provided with two sets of end cover dynamic sealing assemblies (12), and the rear cover (5) is provided with two sets of end cover dynamic sealing assemblies (12). The end cover dynamic sealing assemblies (12) are respectively arranged between the annulus of the front cover (2) and the rear cover (5) and the main shaft (11). The main shaft (11) is provided with a shaft-end mechanical seal assembly (13) at the shaft-end. The shaft-end mechanical seal assembly (13) includes a rotating ring assembly and a stationary ring assembly. The rotating ring assembly includes a rotating ring (13.1), a rotating ring seat (13.2), a stainless steel spring (13.3), and a rotating ring seal (13.4). The stationary ring assembly includes a stationary ring (13.5), a stationary ring seat (13.6), and a stationary ring seal (13.7). The rotating ring seat (13.2), rotating ring (13.1), stationary ring (13.5), and stationary ring seat (13.6) are sequentially sleeved on the shaft-end of the main shaft (11). The rotating ring seat (13.2) is provided with a rotating ring (13.1), and the stationary ring seat (13.6) is provided with a stationary ring (13.5). The rotating ring (13.1) is located on the side close to the stainless steel pump body (1).

2. The stainless steel Roots vacuum pump according to claim 1, characterized in that: The lubricating oil tank (3) is fixedly connected to the front side of the front end cover (2) with an internal hex screw, and the gearbox (6) is fixedly connected to the rear side of the rear end cover (5) with an internal hex screw; the front end of the front end cover (2) is provided with a bearing, and the rear end of the rear end cover (5) is also provided with a bearing, which is sleeved on the main shaft (11).

3. A stainless steel Roots vacuum pump according to claim 1, characterized in that: The motor (15) is connected to the lubricating oil tank (3) through the motor connecting frame (14), which is located outside the coupling (4).

4. A stainless steel Roots vacuum pump according to claim 1, characterized in that: The gearbox (6) is equipped with a synchronizing gear (7), which is sleeved on the end of the main shaft (11).

5. A stainless steel Roots vacuum pump according to claim 1, characterized in that: The cooling water inside the stainless steel pump body (1) and the cooling water inside the end cover are connected to each other through stainless steel pipes to form the cooling system of the Roots pump.

6. A stainless steel Roots vacuum pump according to claim 1, characterized in that: The end cap dynamic sealing assembly (12) includes a skeleton oil seal (12.1), a ceramic bushing (12.2), a piston ring (12.3), a piston ring seat (12.4), an oil baffle (12.5), a sealing bushing (12.6), and an O-ring (12.7). The ceramic bushing (12.2), the oil baffle (12.5), and the piston ring seat (12.4) are sequentially sleeved on the main shaft (11). The piston ring seat (12.4) is located on the side close to the stainless steel pump body (1). The piston ring seat (12.4) is provided with multiple piston rings (12.3), and the outer side of the piston ring seat (12.4) is provided with a sealing bushing (12.6). A skeleton oil seal (12.1) is provided between the ceramic bushing (12.2) and the outer end cap.

7. A stainless steel Roots vacuum pump according to claim 6, characterized in that: An O-ring (12.7) is provided between the ceramic bushing (12.2) and the oil baffle (12.5).

8. A stainless steel Roots vacuum pump according to claim 1, characterized in that: Multiple sets of stainless steel springs (13.3) are provided between the moving ring (13.1) and the moving ring seat (13.2), and a moving ring sealing ring (13.4) is provided inside the moving ring seat (13.2); a stationary ring sealing ring (13.7) is provided between the stationary ring seat (13.6) and the lubricating oil tank (3).

9. A stainless steel Roots vacuum pump according to claim 1, characterized in that: The moving ring (13.1) is a graphite sealing ring, and the moving ring seat (13.2) is a stainless steel support.

10. A stainless steel Roots vacuum pump according to claim 1, characterized in that: The stationary ring (13.5) is a hard alloy sealing ring, and the stationary ring seat (13.6) is a cast iron stationary ring seat.

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