Two-stage dry vacuum pump

Abstract

The utility model discloses a two-stage dry vacuum pump which comprises a pump body, a front end cover is arranged at one end of the pump body, a rear end cover is arranged at the other end of the pump body, and a pair of rotor shafts penetrating through the front end cover and the rear end cover and used for driving rotor blades to rotate is arranged in the pump body. The joint parts of the pump body, the front end cover and the rear end cover with the rotor shaft are provided with reinforced shaft seals; the reinforced shaft seal comprises a spacer sleeve arranged on the peripheral side of the rotor shaft in a sleeving mode, a first-stage rotary seal is installed at one end of the inner side of the spacer sleeve, the shaft seal can be primarily sealed through the first-stage rotary seal in the face of a conveying occasion with large pressure, and when redundant air pressure enters a labyrinth groove, the shaft seal can be tightly sealed through the first-stage rotary seal. The annular labyrinth structure can quickly disturb the linear impact force of air pressure and block the entering air pressure under the cooperation of the first-stage rotary seal and the second-stage rotary seal, the impact speed of the rotary seal is reduced, meanwhile, the bad load and abrasion borne by the rotary seal can be reduced, and the whole pressure field is kept stable.

Description

Technical Field

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

[0002] A two-stage dry vacuum pump is a vacuum pump that uses two stages connected in series. Each stage is equipped with a rotor and vane slots. These synchronously rotate to draw gas from the low-pressure end to the high-pressure end, where it is discharged into the atmosphere or another vacuum system. This pump offers high efficiency, low noise, and stable operation, without generating oil, gas, or water vapor.

[0003] In actual use, since two-stage dry vacuum pumps have a higher pumping speed and pressure ratio than single-stage vacuum pumps, the requirements for the shaft seal matching the pump rotor shaft will be higher, otherwise it will lead to undesirable conditions such as air leakage or pressure relief. At present, the existing two-stage dry vacuum pumps do not have targeted and efficient rotor shaft seal measures. The more common method of strengthening the shaft seal is mainly to use a superposition method to achieve the purpose of strengthening the seal. However, this method has the disadvantage of only treating the symptoms and not the root cause. Especially for some high-pressure conveying occasions, the load and wear rate of the shaft seal will increase significantly, which also increases the subsequent maintenance and use costs, bringing inconvenience to the use of the vacuum pump. Utility Model Content

[0004] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and in the abstract and title of the utility model to avoid obscuring the purpose of this section, the abstract and the title of the utility model, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0005] Therefore, the purpose of the present invention is to provide a two-stage dry vacuum pump to solve the problem that the existing two-stage dry vacuum pump proposed in the above background technology does not have targeted and efficient rotor shaft sealing measures. In particular, for some high-pressure conveying occasions, the load and wear rate borne by the shaft seal will increase significantly, which will also increase the subsequent maintenance and use costs, bringing inconvenience to the use of the vacuum pump.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a two-stage dry vacuum pump, comprising a pump body, wherein one end of the pump body has a front end cover and the other end has a rear end cover, the pump body internally comprises a pair of rotor shafts passing through the front end cover and the rear end cover and used to drive the rotor blades to rotate, and the connection portions between the pump body, the front end cover, the rear end cover and the rotor shaft are provided with reinforced shaft seals;

[0007] The reinforced shaft seal includes a spacer sleeve sleeved on the outer circumference of the rotor shaft, a primary rotary seal installed at one end of the inner side of the spacer sleeve, a secondary rotary seal installed at the other end of the inner side of the spacer sleeve, and an annular labyrinth structure is provided inside the spacer sleeve and between the primary rotary seal and the secondary rotary seal;

[0008] Wherein, the primary rotary seal is close to the air chamber end of the pump body.

[0009] As a preferred solution of the two-stage dry vacuum pump described in the utility model, one end of the pump body has a Roots rotor chamber connected to the air inlet, and the other end of the pump body has a screw rotor chamber connected to the Roots rotor chamber and the exhaust port.

[0010] As a preferred solution of the two-stage dry vacuum pump described in the utility model, a gear box is further provided at one end of the pump body and located on the side of the rear end cover, the active rotor shaft and the auxiliary rotor shaft form an engaged transmission through the gears at the end, and a motor connected to the active rotor shaft is also provided on the outside of the pump body.

[0011] As a preferred solution of a two-stage dry vacuum pump described in the utility model, one end of the inner side of the spacer sleeve has a first rotary seal mounting groove corresponding to the first-level rotary seal, the other end of the inner side of the spacer sleeve has a second rotary seal mounting groove corresponding to the second-level rotary seal, and the center of the inner side of the spacer sleeve has a labyrinth groove corresponding to the annular labyrinth structure.

[0012] As a preferred solution of the two-stage dry vacuum pump described in the utility model, one end of the spacer sleeve has a first cover corresponding to the first rotary seal installation groove, and the other end of the spacer sleeve has a second cover corresponding to the second rotary seal installation groove.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: this two-stage dry vacuum pump, by adopting a multi-stage reinforced shaft seal with a unique structure, can form a preliminary seal on the shaft seal through the first-stage rotary seal when facing a conveying situation with relatively high pressure. When excess air pressure enters the labyrinth groove, the annular labyrinth structure will quickly disrupt the linear impact force of the air pressure, and form a barrier to the incoming air pressure with the cooperation of the first and second stage rotary seals, thereby reducing its impact speed while also reducing the adverse load and wear on the rotary seal, so that the entire pressure field is stabilized. In this way, the pressure on the front and rear rotary seals can be significantly reduced, effectively improving the service stability and service life of the shaft seal, and reducing the later maintenance and use costs of the vacuum pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the overall structure of the utility model;

[0015] Figure 2 This is a schematic diagram of the semi-sectional structure of the reinforced shaft seal of the utility model.

[0016] In the figure: 100, pump body; 110, front end cover; 120, rear end cover; 130, rotor shaft; 140, Roots rotor chamber; 150, screw rotor chamber; 160, gear box; 200, reinforced shaft seal; 210, spacer sleeve; 2101, first rotary seal mounting groove; 2102, second rotary seal mounting groove; 2103, labyrinth groove; 220, annular labyrinth structure; 230, first sealing cover; 240, second sealing cover; 300, motor. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0018] Next, the present invention is described in detail with reference to schematic diagrams. For ease of illustration, cross-sectional views of device structures may be partially enlarged and not to scale when describing the embodiments of the present invention. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0020] Figure 1-Figure 2 Shown is a schematic diagram of the entire structure of a two-stage dry vacuum pump of the utility model, please refer to Figure 1-Figure 2 , a two-stage dry vacuum pump of the present embodiment includes a pump body 100, which has a front end cover 110 at one end of the pump body 100 and a rear end cover 120 at the other end, and a pair of rotor shafts 130 passing through the front end cover 110 and the rear end cover 120 and used to drive the rotor blades to rotate inside the pump body 100, and a reinforced shaft seal 200 is provided at the connection part between the pump body 100, the front end cover 110 and the rear end cover 120 and the rotor shaft 130; the reinforced shaft seal 200 includes a spacer sleeve 210 sleeved on the outer peripheral side of the rotor shaft 130, a primary rotary seal is installed at one end of the inner side of the spacer sleeve 210, and a secondary rotary seal is installed at the other end of the inner side of the spacer sleeve 210, and an annular labyrinth structure 220 is provided inside the spacer sleeve 210 and between the primary rotary seal and the secondary rotary seal; wherein, the primary rotary seal is close to the air chamber end of the pump body 100.

[0021] One end of the pump body 100 houses a Roots rotor chamber 140 connected to the air inlet, while the other end houses a screw rotor chamber 150 connected to both the Roots rotor chamber 140 and the exhaust port. The two-stage coordination of the Roots rotors in the Roots rotor chamber 140 and the screw rotors in the screw rotor chamber 150 significantly improves the pumping speed compared to a single-stage vacuum pump. A gearbox 160 is located at one end of the pump body 100, near the rear end cap 120. The driving rotor shaft and the auxiliary rotor shaft mesh with each other through gears at the ends. A motor 300, connected to the driving rotor shaft, is also located on the outside of the pump body 100. One end of the inner side of the spacer sleeve 210 has a first rotary seal mounting groove 2101 corresponding to the primary rotary seal. The other end of the spacer sleeve 210 has a second rotary seal mounting groove 2102 corresponding to the secondary rotary seal. A labyrinth groove 2103 corresponding to the annular labyrinth structure 220 is located in the center of the inner side of the spacer sleeve 210. One end of the spacer sleeve 210 has a first sealing cover 230 corresponding to the first rotary seal mounting groove 2101, and the other end of the spacer sleeve 210 has a second sealing cover 240 corresponding to the second rotary seal mounting groove 2102. It will be understood that the cooperation of the first rotary seal mounting groove 2101, the first sealing cover 230, the second rotary seal mounting groove 2102, and the second sealing cover 240 enables the positioning and installation of the primary and secondary rotary seals. Furthermore, the connection between the first sealing cover 230 and the sleeve 210, and between the first sealing cover 230 and the sleeve 210, can be achieved through clamps, threaded connections, or other means, without limitation. Specifically, in this embodiment, by adopting a multi-stage reinforced shaft seal 200 with a unique structure, when facing a conveying situation from a relatively large pressure, the shaft seal can be initially sealed by the first-stage rotary seal. When excess air pressure enters the labyrinth groove 2103, the annular labyrinth structure 220 will quickly disrupt the linear impact force of the air pressure, and with the cooperation of the first and second stage rotary seals, it will form a barrier to the incoming air pressure, while reducing its impact speed. At the same time, it can also reduce the adverse load and wear of the rotary seal, so that the entire pressure field can be stabilized. In this way, the pressure on the front and rear rotary seals can be significantly reduced, which effectively improves the stability and life of the shaft seal and reduces the later maintenance and use costs of the vacuum pump.

[0022] Furthermore, the main structure of the reinforced shaft seal 200 in this embodiment is made of metal to ensure the structural strength and service life of the sealing shaft.

[0023] Furthermore, the inner diameter of the annular labyrinth structure 220 in this embodiment is slightly larger than the outer diameter of the rotor shaft 130 . Meanwhile, the patterns of the annular labyrinth structure 220 may be adjacent cross-shaped structures or irregular structures, which are not limited in this embodiment.

[0024] Furthermore, the interior of the reinforced shaft seal 200 in this embodiment is not limited to the three-stage sealing structure consisting of the first rotary seal installation groove 2101, the second rotary seal installation groove 2102 and the labyrinth groove 2103, and can be set to a two-stage sealing, a four-stage sealing structure, etc. according to actual needs.

[0025] While the present invention has been described above with reference to specific embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, as long as no structural conflicts exist, the various features of the embodiments disclosed herein may be combined with one another in any manner, and the omission of an exhaustive description of these combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A two-stage dry vacuum pump, characterized in that: The pump body (100) comprises a pump body (100), wherein one end of the pump body (100) comprises a front end cover (110) and the other end comprises a rear end cover (120), the pump body (100) comprises a pair of rotor shafts (130) passing through the front end cover (110) and the rear end cover (120) and used to drive the rotor blades to rotate, and a reinforced shaft seal (200) is provided at the connection portion between the pump body (100), the front end cover (110), the rear end cover (120) and the rotor shaft (130); The enhanced shaft seal (200) comprises a spacer sleeve (210) sleeved on the outer circumference of the rotor shaft (130), a primary rotary seal being installed at one end of the inner side of the spacer sleeve (210), a secondary rotary seal being installed at the other end of the inner side of the spacer sleeve (210), and an annular labyrinth structure (220) being provided inside the spacer sleeve (210) and between the primary rotary seal and the secondary rotary seal; Wherein, the primary rotary seal is close to the air chamber end of the pump body (100).

2. A two-stage dry vacuum pump according to claim 1, characterized in that: One end of the pump body (100) is provided with a Roots rotor chamber (140) connected to the air inlet, and the other end of the pump body (100) is provided with a screw rotor chamber (150) connected to the Roots rotor chamber (140) and the air outlet.

3. A two-stage dry vacuum pump according to claim 1, characterized in that: A gear box (160) is further provided at one end of the pump body (100) and located on one side of the rear end cover (120), and the driving rotor shaft and the auxiliary rotor shaft form a meshing transmission through the gears at the end. A motor (300) connected to the driving rotor shaft is also provided on the outside of the pump body (100).

4. A two-stage dry vacuum pump according to claim 1, characterized in that: One end of the inner side of the spacer sleeve (210) has a first rotary seal installation groove (2101) corresponding to the primary rotary seal, the other end of the inner side of the spacer sleeve (210) has a second rotary seal installation groove (2102) corresponding to the secondary rotary seal, and the center of the inner side of the spacer sleeve (210) has a labyrinth groove (2103) corresponding to the annular labyrinth structure (220).

5. A two-stage dry vacuum pump according to claim 4, characterized in that: One end of the spacer sleeve (210) has a first sealing cover (230) corresponding to the first rotary seal installation groove (2101), and the other end of the spacer sleeve (210) has a second sealing cover (240) corresponding to the second rotary seal installation groove (2102).

Images