Dry screw vacuum pump sealing structure

Abstract

A kind of dry screw vacuum pump sealing structure belongs to vacuum pump technical field. Including end cover, rotor, sealing sleeve, shaft sleeve, oil retaining ring, bearing and shaft seal, the sealing sleeve, shaft sleeve, oil retaining ring and bearing are sequentially arranged on the rotor shaft handle from the rotor side, the end of the sealing sleeve at both ends is provided with sealing ring respectively at the matching place of rotor shaft handle, the outer wall between the corresponding gas passage of sealing sleeve and shaft sleeve and the cavity wall of sealing sleeve chamber is also provided with multiple sealing rings, the end face between the sealing sleeve and end cover is installed by annular concave-convex step structure cooperation. Advantage: can block the entry of exhaust particulate matter, effectively protect shaft seal, so that shaft seal is not impacted by exhaust pressure, and then prolong service life;Effectively prevent medium with higher content of water vapor, dust particles, corrosive gas and other media from entering the shaft sealing position, and achieve good sealing effect.

Description

Technical Field

[0001] This utility model belongs to the field of vacuum pump technology, specifically relating to a sealing structure for a dry screw vacuum pump. Background Technology

[0002] Dry screw vacuum pumps, also known as oil-free screw vacuum pumps, are pumping devices that utilize a pair of screws rotating synchronously at high speed in opposite directions within a pump casing to generate suction and exhaust. The pump chamber of a dry screw vacuum pump is oil-free, avoiding oil contamination problems, making it particularly suitable for process environments with high cleanliness requirements. Furthermore, it operates without contact or wear, achieving high vacuum levels. Dry screw vacuum pumps offer advantages such as energy saving, environmental friendliness, emission reduction, and maintenance-free operation, and are widely used, especially in special environments with high moisture content, dust, and corrosive gases. However, when pumping gases with high moisture content and corrosiveness, these gases can easily enter the bearing chamber under exhaust pressure, causing lubricating oil emulsification and deterioration. When pumping gases containing dust particles, these particles can easily enter the sealing components, causing wear and premature failure of the seals.

[0003] In view of the above-mentioned existing technology, it is necessary to improve the sealing structure of the existing dry screw vacuum pump. To this end, the applicant has made a useful design, and the technical solution to be introduced below is produced in this context. Utility Model Content

[0004] The purpose of this utility model is to provide a sealing structure for a dry screw vacuum pump. This structure has good sealing performance, is simple in structure but not easy to clog, and has a low failure rate and long maintenance cycle.

[0005] The purpose of this utility model is achieved as follows: a sealing structure for a dry screw vacuum pump includes an end cover, a rotor, a sealing sleeve, a shaft sleeve, an oil baffle ring, a bearing, and a shaft seal. The end cover forms a sealing sleeve chamber at one end facing the pump cavity, and a bearing chamber at the other end. A shaft seal chamber is also formed between the sealing sleeve chamber and the bearing chamber. A gas passage from the outside to the sealing sleeve chamber is provided on the end cover. The rotor has a rotor shaft that passes through the sealing sleeve chamber and the bearing chamber. The sealing sleeve, shaft sleeve, oil baffle ring, and bearing are sequentially mounted on the rotor shaft from the rotor side. The sealing sleeve and the... The sealing sleeve and the sealing chamber are fitted together. The outer wall of the sealing sleeve has a groove that communicates with the gas passage. The bushing corresponds to the position of the shaft seal chamber. The shaft seal is set between the bushing and the cavity wall of the shaft seal chamber. The bearing is equipped with a bearing seat. The oil baffle ring and part of the bearing seat are installed in the bearing chamber. The sealing sleeve is provided with sealing rings at the ends where it mates with the rotor shaft. Multiple sealing rings are also provided between the outer wall of the sealing sleeve corresponding to the gas passage and the bushing and the cavity wall of the sealing sleeve chamber. The sealing sleeve and the end face of the end cover are fitted together by an annular concave-convex step structure.

[0006] In a specific embodiment of this utility model, the end cap forms an end cap protruding step one around the opening of the sealing sleeve chamber on the end face facing the pump cavity. An end cap protruding step two is formed at intervals around the outer ring of the end cap protruding step one. An end cap concave step is formed between the end cap protruding step one and the end cap protruding step two. A sealing sleeve concave step is formed around the circumference on the outer wall of the sealing sleeve, and a sealing ring protruding step is formed around the outer ring of the sealing sleeve concave step. The sealing sleeve concave step is fitted with the end cap protruding step one, and the sealing ring protruding step extends into the end cap concave step and is fitted with the end cap concave step, thereby forming an S-shaped air passage.

[0007] In another specific embodiment of this utility model, a reverse spiral groove is provided on the outer peripheral surface of the sealing ring protrusion step.

[0008] In another specific embodiment of this utility model, the outer diameter of the oil baffle ring is larger than the outer diameter of the bearing, and the oil baffle ring is set tightly against the bearing seat to prevent the lubricating oil overflowing from the bearing chamber from flowing to the pump chamber side.

[0009] In another specific embodiment of this utility model, the outer peripheral edge of the end surface of the oil baffle ring facing the bushing is formed with an annular trapezoidal portion, and the bearing chamber has an oil baffle ring mating ring protruding towards the oil baffle ring at the opening corresponding to the shaft seal chamber. The outer ring of the oil baffle ring mating ring is adapted to be installed with the inner ring of the trapezoidal portion of the oil baffle ring, and works with the shaft seal to prevent oil and gas from entering the pump chamber side to avoid lubricating oil loss.

[0010] Due to the aforementioned structure, this invention offers several advantages over existing technologies: it effectively prevents the entry of exhaust particles, protecting the shaft seal from the impact of exhaust pressure and extending its service life. In applications requiring the removal of media with high concentrations of water vapor, dust particles, or corrosive gases, compressed gas can be introduced into the gas channel. The compressed gas flows to the left under the obstruction of two sets of sealing rings, and the concave-convex step structure further reduces gas consumption and maintains internal pressure. Finally, it is released through the anti-spiral groove, effectively preventing the aforementioned media from entering the shaft seal position, achieving a good sealing effect. Furthermore, the sealing structure is less prone to clogging, resulting in a longer maintenance cycle. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1 Enlarged view of part A.

[0012] In the figure: 1. End cover, 11. Sealing sleeve chamber, 12. Bearing chamber, 121. Oil baffle ring mating ring, 13. Shaft seal chamber, 14. Gas passage, 15. End cover raised step one, 16. End cover raised step two, 17. End cover concave step; 2. Rotor, 21. Rotor shaft; 3. Sealing sleeve, 30. S-shaped gas passage, 31. Groove, 32. Sealing sleeve concave step, 33. Sealing ring raised step, 331. Reverse spiral groove; 4. Shaft sleeve; 5. Oil baffle ring, 51. Trapezoidal part; 6. Bearing, 61. Bearing housing; 7. Shaft seal; 8. Sealing ring; 9. Sealing ring. Detailed Implementation

[0013] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. However, the description of the embodiments is not a limitation on the technical solution. Any formal but not substantive changes made based on the concept of this utility model should be considered within the protection scope of this utility model.

[0014] In the following description, all directional (or orientational) concepts involving up, down, left, right, front, and back refer to the position of the figure being described, and are intended to facilitate public understanding. Therefore, they should not be construed as a special limitation on the technical solution provided by this utility model.

[0015] See Figure 1This utility model relates to a sealing structure for a dry screw vacuum pump. The dry screw vacuum pump includes a pump casing, in which a pair of screws rotate synchronously at high speed in opposite directions to generate suction and exhaust. The sealing structure corresponds to the shaft seal position of the vacuum pump and includes an end cover 1, a rotor 2, a sealing sleeve 3, a shaft sleeve 4, an oil baffle ring 5, a bearing 6, and a shaft seal 7. The end cover 1 forms a sealing sleeve chamber 11 at one end facing the pump cavity, and a bearing chamber 12 at the other end. A shaft seal chamber 13 is also formed between the sealing sleeve chamber 11 and the bearing chamber 12. A gas passage 14 is provided on the end cover 1, which extends from the outside to the sealing sleeve chamber 11. The rotor 2 has a rotor shaft 21 that passes through the sealing sleeve chamber 11 and the bearing chamber 12. The sealing sleeve 3, shaft sleeve 4, oil baffle ring 5, and bearing 6 are sequentially mounted on the rotor shaft 21 from the rotor 2 side. The sealing sleeve 3 is fitted into the sealing sleeve chamber 11, and a groove 31 communicating with the gas passage 14 is formed on the outer wall of the sealing sleeve 3. The bushing 4 corresponds to the position of the shaft sealing chamber 13, and the shaft seal 7 is disposed between the bushing 4 and the cavity wall of the shaft sealing chamber 13. The bearing 6 is equipped with a bearing seat 61, and the oil baffle ring 5 and part of the bearing seat 61 are installed in the bearing chamber 12. The bearing seat 61 has a lubricating oil inlet channel and an overflow channel.

[0016] The outer diameter of the oil baffle ring 5 is larger than that of the bearing 6. The oil baffle ring 5 is tightly fitted against the bearing housing 61 to prevent lubricating oil overflowing from the bearing chamber 12 from flowing to the pump cavity side. The outer peripheral edge of the end surface of the oil baffle ring 5 facing the bushing 4 has an annular trapezoidal portion 51. The bearing chamber 12 has an oil baffle ring mating ring 121 protruding towards the oil baffle ring 5 at the opening corresponding to the shaft seal chamber 13. The outer ring of the oil baffle ring mating ring 121 is fitted and installed to fit the inner ring of the trapezoidal portion 51 of the oil baffle ring 5. The oil baffle ring 5, in conjunction with the shaft seal 7, effectively prevents oil and gas from entering the pump cavity side, thus avoiding lubricating oil loss.

[0017] Furthermore, the sealing sleeve 3 is provided with sealing rings 8 at the ends of the two ends where it mates with the rotor shaft 21; a plurality of sealing rings 9 are also provided between the outer wall of the corresponding gas channel 13 and the shaft sleeve 4 of the sealing sleeve 3 and the cavity wall of the sealing sleeve chamber 11. In this embodiment, a pair of the sealing rings 9 are schematically provided.

[0018] See Figure 2 and combined Figure 1Furthermore, the sealing sleeve 3 and the end cover 1 are fitted together by an annular stepped structure. Specifically, the end cover 1 forms a raised step 15 around the opening of the sealing sleeve chamber 11 on the end face facing the pump cavity. A second raised step 16 is formed at intervals around the outer ring of the first raised step 15. A recessed step 17 is formed between the first raised step 15 and the second raised step 16. A recessed step 32 is formed circumferentially on the outer wall of the sealing sleeve 3, and a sealing ring raised step 33 is formed around the outer ring of the recessed step 32. The recessed step 32 fits into the first raised step 15, and the sealing ring raised step 33 extends into the recessed step 17 and fits into the recessed step 17, thereby forming an S-shaped air passage 30. A reverse spiral groove 331 is provided on the outer circumferential surface of the sealing ring raised step 33.

[0019] During operation, under the action of exhaust pressure, the dry screw vacuum pump discharges gas towards the vacuum pump shaft seal. First, the anti-spiral groove 331 rotates to block the entry of exhaust particles. Second, the airflow speed is slowed down by the S-shaped air passage 30. Finally, a pair of sealing rings 9 block the airflow, effectively protecting the shaft seal 7 from the impact of exhaust pressure, thereby extending its service life. When pumping media with high content of water vapor, dust particles, corrosive gases, etc., compressed gas can be introduced into the gas passage 14. The compressed gas flows to the left side of the pump chamber under the obstruction of the pair of sealing rings 9. Then, through the tiny gaps formed between the end cover step-15 and the sealing sleeve 3, and between the end cover step-15 and the sealing ring step-33, and the S-shaped air passage 30, the consumption of compressed gas can be reduced and the internal pressure can be maintained. Finally, it is released into the exhaust chamber through the anti-spiral groove 331. The above-mentioned media will not be able to enter the shaft seal position, thus achieving a very good sealing effect. Moreover, the sealing structure is not easy to clog, the maintenance cycle is long, and the invention objective is achieved.

Claims

1. A sealing structure for a dry screw vacuum pump, comprising an end cover (1), a rotor (2), a sealing sleeve (3), a shaft sleeve (4), an oil baffle ring (5), a bearing (6), and a shaft seal (7), wherein the end cover (1) forms a sealing sleeve chamber (11) at one end facing the pump chamber, and a bearing chamber (12) at the other end, and a shaft seal chamber (13) is formed between the sealing sleeve chamber (11) and the bearing chamber (12), and a gas passage (14) is provided on the end cover (1) to the sealing sleeve chamber (11) from the outside, the rotor (2) having a rotor shaft (21) passing through the sealing sleeve chamber (11) and the bearing chamber (12), wherein the sealing sleeve (3), the shaft sleeve (4), the oil baffle ring (5), and the bearing (6) are sequentially mounted on the rotor shaft (21) from the rotor (2) side, wherein, The sealing sleeve (3) is fitted with the sealing sleeve chamber (11). A groove (31) communicating with the gas passage (14) is formed on the outer wall of the sealing sleeve (3). The bushing (4) is located at the position of the shaft seal chamber (13). The shaft seal (7) is set between the bushing (4) and the cavity wall of the shaft seal chamber (13). The bearing (6) is equipped with a bearing seat (61). The oil baffle (5) and part of the bearing seat (61) are installed in the bearing chamber (12). The sealing sleeve (3) is characterized by having sealing rings (8) at the ends of the sealing sleeve (3) where it fits with the rotor shaft (21). Multiple sealing rings (9) are also provided between the outer wall of the sealing sleeve (3) corresponding to the gas passage (14) and the bushing (4) and the cavity wall of the sealing sleeve chamber (11). The sealing sleeve (3) and the end face of the end cover (1) are fitted together by an annular concave-convex step structure.

2. The sealing structure of a dry screw vacuum pump according to claim 1, characterized in that: The end cap (1) forms an end cap protrusion step one (15) around the opening of the sealing sleeve chamber (11) on the end face facing the pump cavity. An end cap protrusion step two (16) is formed at intervals on the outer ring of the end cap protrusion step one (15). An end cap concave step (17) is formed between the end cap protrusion step one (15) and the end cap protrusion step two (16). A sealing sleeve concave step (32) is formed on the outer wall of the sealing sleeve (3) in the circumferential direction. A sealing ring protrusion step (33) is formed on the outer ring of the sealing sleeve concave step (32). The sealing sleeve concave step (32) is fitted with the end cap protrusion step one (15). The sealing ring protrusion step (33) extends into the end cap concave step (17) and is fitted with the end cap concave step (17), thereby forming an S-shaped air passage (30).

3. The sealing structure of a dry screw vacuum pump according to claim 2, characterized in that: The outer circumferential surface of the sealing ring protrusion step (33) is provided with a reverse spiral groove (331).

4. The sealing structure of a dry screw vacuum pump according to claim 1, characterized in that: The outer diameter of the oil baffle ring (5) is larger than the outer diameter of the bearing (6). The oil baffle ring (5) is set close to the bearing seat (61) to prevent the lubricating oil overflowing from the bearing chamber (12) from flowing to the pump chamber side.

5. The sealing structure of a dry screw vacuum pump according to claim 1, characterized in that: The outer peripheral edge of the oil baffle ring (5) facing the bushing (4) has a trapezoidal portion (51) in the shape of an annulus. The bearing chamber (12) has an oil baffle ring mating ring (121) protruding towards the oil baffle ring (5) at the opening corresponding to the shaft seal chamber (13). The outer ring of the oil baffle ring mating ring (121) is adapted to the inner ring of the trapezoidal portion (51) of the oil baffle ring (5) and is used in conjunction with the shaft seal (7) to prevent oil and gas from entering the pump chamber side to avoid loss of lubricating oil.

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