Screw vacuum pump

Abstract

The utility model relates to the technical field of vacuum pump, and disclose screw vacuum pump, including the pump shell, the pump shell opening side is provided with sealing assembly, the inner wall rotation of pump shell far from sealing assembly one side is installed with the main shaft, the main shaft is penetrated in sealing assembly and extends to the outside of pump shell, the cooperation of gas assembly through condensation copper pipe and drainage spiral, high -efficient recovery oil mist in exhaust and recycling, reduce lubricating oil waste, filter screen and pressure gauge guarantee air inlet cleanliness and pressure stability in the air inlet end, through the cooperation of pressure sensing cavity and pressure guide pipe, make sealing force can change automatically with the vacuum degree inside pump shell and adjust, provide enough sealing force under low vacuum high pressure difference working condition and prevent leakage, reduce sealing force under high vacuum low pressure difference working condition and avoid excessive wear, the design of bellows and sealing pad further strengthens sealing effect, ensures the sealing reliability under the whole working condition, solved the problem that traditional sealing structure is difficult to adapt to different vacuum working condition.

Description

Technical Field

[0001] This utility model relates to the field of vacuum pump technology, specifically to screw vacuum pumps. Background Technology

[0002] As an oil-free dry vacuum pump, the screw vacuum pump is widely used in fields with stringent requirements for vacuum environment and cleanliness, such as semiconductor manufacturing, biomedicine, and chemical reactions, thanks to its advantages of wide pumping speed range, high ultimate vacuum, and no oil pollution.

[0003] Currently, screw vacuum pumps on the market mainly consist of a pump casing, rotor, motor, sealing structure, and inlet / outlet pipes. Existing equipment has a major problem: the sealing force of the sealing structure cannot be adjusted according to changes in the vacuum level inside the pump casing. Under low vacuum and high pressure differential conditions, the pre-tightening force may be insufficient, leading to gas leakage and affecting the stability of the vacuum environment. Conversely, under high vacuum and low pressure differential conditions, excessive sealing force will exacerbate wear on the dynamic and static rings, shorten the lifespan of the sealing components, and increase maintenance costs. Furthermore, the direct emission of lubricating oil mist contained in the exhaust not only wastes resources but also pollutes the environment. If the oil mist adheres to the inner wall of the pipe, long-term accumulation will clog the pipe, reduce exhaust efficiency, and further affect the pump's operational stability.

[0004] Therefore, a screw vacuum pump is proposed to solve the problem that traditional sealing structures are difficult to adapt to different vacuum conditions. Utility Model Content

[0005] The purpose of this invention is to provide a screw vacuum pump to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a screw vacuum pump, including a pump housing, a sealing assembly provided on one side of the pump housing opening, and a main shaft rotatably mounted on the inner wall of the pump housing away from the sealing assembly, the main shaft passing through the sealing assembly and extending to the outside of the pump housing;

[0007] The sealing assembly includes a sealing end cap, which is bolted to one side of the pump housing opening. A dynamic sealing ring is fixedly installed on the outer wall of the main shaft, located on the side where the main shaft passes through the sealing end cap. A static sealing ring is fitted to the side of the dynamic sealing ring away from the pump housing. A bellows is welded to the side of the static sealing ring away from the dynamic sealing ring. The end of the bellows away from the static sealing ring is welded to the inner wall of the sealing end cap. A warning spring is also fixedly installed between the static sealing ring and the inner wall of the sealing end cap, located on the outside of the bellows.

[0008] The pressure sensing chamber, composed of the inner wall of the sealing end cover, the outer surface of the bellows, and the side of the static sealing ring furthest from the dynamic sealing ring, is used to sense the pressure inside the pump. This pressure sensing chamber is connected to the inside of the pump casing via a pressure-conducting pipe, which is located inside the sealing end cover.

[0009] The sealing cavity is formed by the side of the static sealing ring away from the dynamic sealing ring, the inner side of the bellows, and the inner wall of the sealing end cover, and is used to adjust the position of the static sealing ring.

[0010] Preferably, a sealing gasket is provided between the sealing cavity, the sealing end cover, and the main shaft. One end of the main shaft extends out of the sealing end cover and is connected to the motor output end. The motor is fixedly installed on the side of the sealing end cover away from the pump casing.

[0011] Preferably, it also includes an air intake assembly, which is located on the outside of the pump housing at the end away from the sealing assembly. The air intake assembly includes an air intake pipe that passes through the pump housing for air intake into the equipment. A filter screen is installed at the interface of the air intake pipe by bolts.

[0012] Preferably, a pressure gauge is installed on the outside of the air intake pipe for real-time pressure monitoring.

[0013] Preferably, it also includes an exhaust assembly, which is located on the outside of the pump housing at the end away from the intake assembly. The exhaust assembly includes an exhaust pipe, which is fixedly connected to the pump housing via a connecting pipe. A guide spiral is fixedly installed inside the exhaust pipe near the connecting pipe. A condensing copper tube is fixedly installed inside the exhaust pipe and surrounds the guide spiral. An oil droplet guide groove is opened inside the exhaust pipe below the guide spiral. An oil droplet recovery hole is opened inside the oil droplet guide groove, which penetrates the exhaust pipe and is used to connect to an oil droplet recovery pipe.

[0014] Preferably, the inlet and outlet of the condenser copper tube are connected to an external condenser circulation device, and the end of the oil droplet recovery tube away from the oil droplet recovery hole is connected to a lubricating oil recovery device.

[0015] Preferably, a frame is provided at the bottom of the pump casing for supporting and fixing the equipment. The pump casing and the frame are connected by bolts. A secondary shaft is rotatably installed between the frame and the sealing end cover, parallel to the main shaft. Two synchronously rotating rotors are fixedly installed on the outside of the main shaft and the secondary shaft.

[0016] Compared with the prior art, the present invention provides a screw vacuum pump, which has the following beneficial effects:

[0017] 1. This screw vacuum pump, through the cooperation of the pressure sensing chamber and the pressure guiding pipe, enables the sealing force to be automatically adjusted according to the change of vacuum degree inside the pump casing. It provides sufficient sealing force to prevent leakage under low vacuum and high pressure differential conditions, and reduces the sealing force to avoid excessive wear under high vacuum and low pressure differential conditions. At the same time, the design of the bellows and sealing gasket further enhances the sealing effect, ensuring sealing reliability under all operating conditions, and solving the problem that traditional sealing structures are difficult to adapt to different vacuum conditions.

[0018] 2. This screw vacuum pump's exhaust assembly, through the cooperation of a condenser copper tube and a guide spiral, efficiently recovers and recycles oil mist in the exhaust, reducing lubricant waste. Under high vacuum conditions, the sealing force automatically decreases, reducing friction loss on the sealing surface and lowering motor drive energy consumption. At the same time, the filter and pressure gauge at the intake end ensure the cleanliness and pressure stability of the intake air, indirectly reducing additional energy consumption caused by impurities or abnormal pressure, thus improving the economic efficiency of the device. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the appearance and structure of this utility model;

[0021] Figure 2 This is a schematic diagram of the sealing assembly structure of this utility model;

[0022] Figure 3 This utility model Figure 2 Enlarged schematic diagram of the structure at point A in the middle;

[0023] Figure 4 This is a schematic diagram of the air outlet component structure of this utility model.

[0024] In the diagram: 1. Pump casing; 2. Sealing assembly; 201. Sealing end cover; 202. Dynamic sealing ring; 203. Static sealing ring; 204. Warning spring; 205. Bellows; 206. Sealing cavity; 207. Pressure sensing cavity; 208. Pressure guide pipe; 209. Sealing gasket; 3. Motor; 4. Inlet assembly; 401. Inlet pipe; 402. Filter screen; 403. Pressure gauge; 5. Outlet assembly; 501. Connecting pipe; 502. Outlet pipe; 503. Drainage spiral; 504. Condensation copper pipe; 505. Oil droplet guide groove; 506. Oil droplet recovery hole; 507. Oil droplet recovery pipe; 6. Frame; 7. Main shaft; 8. Secondary shaft. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0027] Please see Figure 1-3 The present invention provides a technical solution: a screw vacuum pump, including a pump housing 1, a sealing component 2 is provided on the open side of the pump housing 1, and a main shaft 7 is rotatably mounted on the inner wall of the pump housing 1 away from the sealing component 2, the main shaft 7 passing through the sealing component 2 and extending to the outside of the pump housing 1.

[0028] The sealing assembly 2 includes a sealing end cap 201, which is bolted to one side of the pump housing 1 opening. A dynamic sealing ring 202 is fixedly installed on the outer wall of the main shaft 7, located on the side of the main shaft 7 that passes through the sealing end cap 201. A static sealing ring 203 is fitted to the side of the dynamic sealing ring 202 away from the pump housing 1. A bellows 205 is welded to the side of the static sealing ring 203 away from the dynamic sealing ring 202. The end of the bellows 205 away from the static sealing ring 203 is welded to the inner wall of the sealing end cap 201. A warning spring 204 is also fixedly installed between the static sealing ring 203 and the inner wall of the sealing end cap 201, located on the outside of the bellows 205.

[0029] The pressure sensing chamber 207 is formed by the inner wall of the sealing end cover 201, the outer side of the bellows 205, and the side of the static sealing ring 203 away from the dynamic sealing ring 202. This chamber is used to sense the pressure inside the pump. The pressure sensing chamber 207 is connected to the inside of the pump casing 1 via a pressure guiding pipe 208, which is located inside the sealing end cover 201.

[0030] The sealing cavity 206 is formed by the side of the static sealing ring 203 away from the dynamic sealing ring 202, the inner side of the bellows 205, and the inner wall of the sealing end cover 201, and is used to adjust the position of the static sealing ring 203.

[0031] Through the cooperation of the sealing end cap 201, dynamic sealing ring 202, static sealing ring 203, warning spring 204, bellows 205, pressure sensing chamber 207, and pressure guiding pipe 208, the sealing force can be automatically adjusted according to the vacuum level inside the pump casing 1. Under low vacuum conditions, the pressure inside the pressure sensing chamber 207 increases, and the elastic force of the warning spring 204 enhances the sealing force to prevent leakage. Under high vacuum conditions, the pressure inside the pressure sensing chamber 207 decreases, and only the warning spring 204 provides a moderate sealing force to avoid excessive wear of the dynamic sealing ring 202 and static sealing ring 203, thus extending the life of the sealing pair. The bellows 205 can move and extend axially with the static sealing ring 203 to ensure the sealing performance of the sealing chamber 206. The design of the pressure sensing chamber 207 and pressure guiding pipe 208 makes the sealing adjustment more precise, significantly improving the adaptability and reliability of the sealing assembly 2.

[0032] Furthermore, a sealing gasket 209 is provided between the sealing cavity 206, the sealing end cover 201, and the main shaft 7. One end of the main shaft 7 extending out of the sealing end cover 201 is connected to the output end of the motor 3. The motor 3 is fixedly installed on the side of the sealing end cover 201 away from the pump housing 1.

[0033] The sealing gasket 209 can effectively fill the gap between the sealing cavity 206 and the sealing end cover 201 and the main shaft 7, prevent gas from leaking out of the gap, and further enhance the sealing effect.

[0034] Please see Figure 1 and Figure 4 Furthermore, it is also found that the pump housing 1 includes an air intake assembly 4, which is located on the outside of the pump housing 1 at the end away from the sealing assembly 2. The air intake assembly 4 includes an air intake pipe 401, which passes through the pump housing 1 and is used for air intake of the equipment. A filter screen 402 is installed at the interface of the air intake pipe 401 by bolts.

[0035] The air intake pipe 401 of the air intake assembly 4 provides a stable channel for gas to enter the pump housing 1. The filter screen 402 at the interface can filter impurities in the air intake, preventing impurities from entering the pump housing 1 and wearing the rotor or affecting the sealing effect of the sealing assembly 2, thus extending the life of the internal components of the equipment. The filter screen 402 is installed by bolts, which is convenient for later disassembly, cleaning or replacement, reducing maintenance costs.

[0036] Furthermore, a pressure gauge 403 is provided on the outside of the air intake pipe 401 for real-time pressure monitoring.

[0037] The intake pressure status can be intuitively monitored through the pressure gauge 403, and abnormal intake pressure can be detected in time. This facilitates the adjustment of intake parameters or troubleshooting of intake system faults, and avoids the instability of the vacuum inside the pump casing 1 caused by abnormal intake pressure, which in turn affects the sealing effect of the sealing component 2 or the normal operation of the rotor, thus ensuring the stability of equipment operation.

[0038] Furthermore, it also includes an exhaust assembly 5, which is located on the outside of the pump housing 1 at the end away from the intake assembly 4. The exhaust assembly 5 includes an exhaust pipe 502, which is fixedly connected to the pump housing 1 through a connecting pipe 501. A guide spiral 503 is fixedly installed inside the exhaust pipe 502 near the connecting pipe 501. A condensing copper pipe 504 is fixedly installed inside the exhaust pipe 502 and surrounds the guide spiral 503. An oil droplet guide groove 505 is opened inside the exhaust pipe 502 and located below the guide spiral 503. An oil droplet collection hole 506 is opened inside the oil droplet guide groove 505 and passes through the exhaust pipe 502 for connecting an oil droplet collection pipe 507.

[0039] The guiding spiral 503 inside the gas outlet pipe 502 extends the gas residence time, allowing the gas to fully contact the condensing copper pipe 504 and improving the oil mist condensation efficiency; the oil droplet guide groove 505, together with the oil droplet recovery hole 506 and the oil droplet recovery pipe 507, can efficiently collect the oil droplets formed by condensation and realize oil mist recovery.

[0040] Furthermore, the inlet and outlet of the condensing copper pipe 504 are connected to an external condensing circulation device, and the end of the oil droplet recovery pipe 507 away from the oil droplet recovery hole 506 is connected to a lubricating oil recovery device.

[0041] The condensing copper tube 504 is connected to the external condensing circulation equipment to continuously obtain low-temperature cooling water, ensuring the stability of the oil mist condensation effect and avoiding the decrease in oil mist recovery efficiency due to insufficient cooling; the oil droplet recovery tube 507 is connected to the lubricating oil recovery device, so that the recovered oil mist can be reused, reducing the cost of device use, and avoiding direct discharge of waste oil that causes environmental pollution.

[0042] Furthermore, a frame 6 is provided at the bottom of the pump casing 1 for supporting and fixing the equipment. The pump casing 1 and the frame 6 are connected by bolts. A secondary shaft 8 is rotatably installed between the frame 6 and the sealing end cover 201, parallel to the main shaft 7. Two synchronously rotating rotors are fixedly installed on the outside of the main shaft 7 and the secondary shaft 8.

[0043] The frame 6 is connected to the pump housing 1 by bolts, which provides stable support for the pump body, reduces vibration during equipment operation, and prevents the dynamic sealing ring 202 and static sealing ring 203 of the sealing assembly 2 from shifting due to vibration, or loosening of the connection between the air inlet and outlet components; the rotors of the main shaft 7 and the secondary shaft 8 rotate synchronously in opposite directions to ensure gas suction and compression efficiency, and provide a stable working condition for the oil mist recovery of the outlet assembly 5 and the sealing adjustment of the sealing assembly 2.

[0044] In actual operation, the motor 3 is started, which drives the main shaft 7 and the dynamic sealing ring 202 fixed outside the main shaft 7 to rotate synchronously. The secondary shaft 8, which is parallel to the main shaft 7, rotates synchronously in the opposite direction with the main shaft 7 under the transmission action. The external rotors of the two work together to achieve gas suction. Gas enters the pump housing 1 from the air intake pipe 401 of the air intake assembly 4. The filter screen 402 at the interface of the air intake pipe 401 performs preliminary filtration of the gas to prevent impurities from entering the pump housing 1. The pressure gauge 403 monitors the pressure inside the air intake pipe 401 in real time to facilitate the monitoring of the air intake status.

[0045] After being compressed by the rotor, the gas inside the pump casing 1 enters the outlet pipe 502 of the outlet assembly 5 through the connecting pipe 501. The guiding spiral 503 in the outlet pipe 502 guides the gas to flow along the spiral path, extending the gas residence time. The cooling water of the external condensation circulation equipment is introduced into the condensing copper pipe 504 surrounding the guiding spiral 503 to cool the oil mist-containing gas. The oil mist condenses into oil droplets upon encountering the condenser and falls into the oil droplet guide groove 505 below under the action of gravity. Then, it enters the oil droplet recovery pipe 507 through the oil droplet recovery hole 506 and finally flows into the lubricating oil recovery device for recovery.

[0046] Throughout the operation, the sealing assembly 2 ensures the internal sealing of the pump casing 1: When the pump is not started or is under atmospheric pressure, the pressure in the pressure sensing chamber 207 is atmospheric pressure, and the elastic force of the warning spring 204 pushes the static sealing ring 203 to fit against the dynamic sealing ring 202, providing basic sealing force; when the pump starts and enters the low vacuum condition, the internal pressure of the pump casing 1 is transmitted to the pressure sensing chamber 207 through the pressure guide pipe 208, and the pressure acts on the back of the static sealing ring 203, which is superimposed with the elastic force of the warning spring 204 to increase the sealing force to overcome the high pressure difference and prevent leakage; after entering the high vacuum condition, the internal pressure of the pump casing 1 decreases, and the pressure in the pressure sensing chamber 207 decreases synchronously. The pressure on the back of the static sealing ring 203 decreases, and the sealing force relies only on the elastic force of the warning spring 204 to avoid excessive wear of the sealing surface; the bellows 205 extends and retracts with the axial movement of the static sealing ring 203 to ensure the sealing of the sealing chamber 206, and the sealing gasket 209 further prevents gap leakage between the sealing chamber 206 and the sealing end cover 201 and the main shaft 7. The frame 6 provides support and fixation for the entire pump body, ensuring stable operation of the equipment.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A screw vacuum pump, comprising a pump housing (1), characterized in that: A sealing assembly (2) is provided on the opening side of the pump housing (1), and a main shaft (7) is rotatably installed on the inner wall of the pump housing (1) away from the sealing assembly (2). The main shaft (7) passes through the sealing assembly (2) and extends to the outside of the pump housing (1). The sealing assembly (2) includes a sealing end cap (201), which is fixedly installed on one side of the opening of the pump housing (1) by bolts. A dynamic sealing ring (202) is fixedly installed on the outer wall of the main shaft (7) on the side where the main shaft (7) passes through the sealing end cap (201). A static sealing ring (203) is fitted on the side of the dynamic sealing ring (202) away from the pump housing (1). A bellows (205) is welded and fixed on the side of the static sealing ring (203) away from the dynamic sealing ring (202). One end of the bellows (205) away from the static sealing ring (203) is welded and installed on the inner wall of the sealing end cap (201). A warning spring (204) is also fixedly installed between the static sealing ring (203) and the inner wall of the sealing end cap (201) on the outside of the bellows (205). The pressure sensing chamber (207) is formed by the inner wall of the sealing end cover (201), the outer side of the bellows (205), and the side of the static sealing ring (203) away from the dynamic sealing ring (202). It is used to sense the pressure inside the pump. The pressure sensing chamber (207) is connected to the inside of the pump casing (1) through a pressure guiding pipe (208). The pressure guiding pipe (208) is located inside the sealing end cover (201). The sealing cavity (206) is formed by the side of the static sealing ring (203) away from the dynamic sealing ring (202), the inner side of the bellows (205), and the inner wall of the sealing end cap (201), which is used to adjust the position of the static sealing ring (203).

2. The screw vacuum pump according to claim 1, characterized in that: A sealing gasket (209) is provided between the sealing cavity (206), the sealing end cover (201), and the main shaft (7). The main shaft (7) extends out of the sealing end cover (201) and is connected to the output end of the motor (3). The motor (3) is fixedly installed on the side of the sealing end cover (201) away from the pump casing (1).

3. The screw vacuum pump according to claim 1, characterized in that: It also includes an air intake assembly (4), which is located on the outside of the pump housing (1) away from the sealing assembly (2). The air intake assembly (4) includes an air intake pipe (401) that passes through the pump housing (1) for air intake of the equipment. A filter screen (402) is installed at the interface of the air intake pipe (401) by bolts.

4. The screw vacuum pump according to claim 3, characterized in that: A pressure gauge (403) is installed on the outside of the air intake pipe (401) for real-time pressure monitoring.

5. The screw vacuum pump according to claim 1, characterized in that: It also includes an exhaust assembly (5), which is located on the outside of the pump housing (1) away from the intake assembly (4). The exhaust assembly (5) includes an exhaust pipe (502), which is fixedly connected to the pump housing (1) through a connecting pipe (501). A flow-guiding spiral (503) is fixedly installed inside the exhaust pipe (502) near the connecting pipe (501). A condensing copper pipe (504) is fixedly installed inside the exhaust pipe (502) and surrounds the flow-guiding spiral (503). An oil droplet guide groove (505) is opened inside the exhaust pipe (502) and located below the flow-guiding spiral (503). An oil droplet recovery hole (506) is opened inside the oil droplet guide groove (505) and passes through the exhaust pipe (502) for connecting the oil droplet recovery pipe (507).

6. The screw vacuum pump according to claim 5, characterized in that: The inlet and outlet of the condensing copper pipe (504) are connected to an external condensing circulation device, and the end of the oil droplet recovery pipe (507) away from the oil droplet recovery hole (506) is connected to a lubricating oil recovery device.

7. The screw vacuum pump according to claim 1, characterized in that: The bottom of the pump casing (1) is provided with a frame (6) for supporting and fixing the equipment. The pump casing (1) and the frame (6) are connected by bolts. A secondary shaft (8) is rotatably installed between the frame (6) and the sealing end cover (201), parallel to the main shaft (7). Two synchronously rotating rotors are fixedly installed on the outside of the main shaft (7) and the secondary shaft (8).

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