Vacuum pump based on advanced pressure relief and one-way exhaust structure and working method of vacuum pump

Abstract

The invention provides a vacuum pump based on an advanced pressure relief and one-way exhaust structure and a working method of the vacuum pump, and belongs to the technical field of roots pump exhaust structure design of multi-stage dry vacuum pumps. A group of exhaust channels are additionally arranged at the middle stage to serve as advanced pressure relief exhaust channels, and aiming at the easy compression characteristic of high-flow gas compression at the initial stage of air exhaust, gas which reaches preset exhaust pressure at the middle stage is exhausted out of a rotor group working cavity of the vacuum pump in advance through a pressure relief opening; and the vacuum pump does not need to continuously and sequentially perform subsequent-stage compression like a traditional vacuum pump which only exhausts air from the tail part, so that the air exhaust efficiency of the vacuum pump can be improved, the energy waste is reduced, and the aim of saving energy is fulfilled. And meanwhile, the extensive mode of evenly distributing pressure relief openings in the prior art is broken through, accurate matching of the advanced pressure relief channel and the dynamic pressure characteristics of the multi-stage pump is achieved, and the air exhaust efficiency is remarkably improved while the system reliability is guaranteed.

Description

Technical Field

[0001] This invention belongs to the technical field of Roots pump exhaust structure design for multi-stage dry vacuum pumps. Specifically, it relates to a vacuum pump based on a pre-depressurization and unidirectional exhaust structure and its working method, which has the characteristics of working in a wide pressure range, having a large compression ratio, and being able to directly exhaust to the atmosphere. Background Technology

[0002] Roots vacuum pumps, as a type of positive displacement vacuum pump, have been widely used in many key fields such as semiconductor manufacturing, chemical production, food processing, pharmaceutical research and development, and metallurgy due to their significant advantages, including high pumping speed over a wide pressure range, rapid start-up, and insensitivity to gas impurities.

[0003] As an upgraded form of the Roots vacuum pump, the multistage Roots pump forms a progressively compressed vacuum system by connecting multiple pump stages in series. This enables the achievement of even lower ultimate vacuum levels (multistage configurations can reach below 1 Pa), demonstrating irreplaceable advantages in high-vacuum applications such as semiconductor wafer-level vacuum deposition and aerospace material vacuum melting. Thanks to its progressively increasing compression ratio, it can maintain a stable pumping speed over a wide pressure range, effectively meeting the stringent vacuum environment requirements of precision manufacturing.

[0004] However, in the initial stage of pumping, the operating efficiency of multi-stage Roots pumps still faces significant bottlenecks. The core problem lies in the inability to prematurely discharge gas that has already reached its discharge pressure. Specifically, the pump stages of a multi-stage Roots pump operate in a fixed series sequence, requiring gas to pass through the first stage for intake, intermediate stages for compression, and the final stage for discharge, forming a complete process. In the initial stage of pumping, the system pressure rapidly decreases from atmospheric pressure to the target vacuum level. Some intermediate or final stages may have already reached their discharge pressure during gas transmission. However, due to the fixed inter-stage linkage structure, this gas still needs to complete the remaining stroke with the rotor before it can be discharged from the final stage, leading to an "overcompression" phenomenon—gas that has already met the discharge conditions is continuously compressed within the pump chamber. This not only consumes extra energy but also generates redundant heat due to unnecessary compression work, exacerbating the pump body temperature rise. This "overcompression" not only reduces the pump's energy efficiency but also severely affects the pumping efficiency, significantly prolonging the time it takes for the system to reach the target vacuum level.

[0005] In the prior art, patent CN222102292 discloses a multi-stage pressure relief structure for a vacuum pump, which has explored the optimization of exhaust in multi-stage vacuum pumps. This technical solution involves setting multiple interconnected chambers of decreasing volume within the housing, allowing gas to move progressively from larger to smaller chambers. Pressure relief ports are provided on the top cover corresponding to each chamber, and the opening and closing of these ports are dynamically controlled by a sealing assembly based on the chamber pressure. From a structural design perspective, its initial intention is to improve pumping efficiency and ensure smooth exhaust through multi-stage pressure relief; however, it has significant limitations in practical applications: On the one hand, the structure adopts a "full-stage pressure relief" design, with pressure relief ports configured in each stage before the final stage, resulting in high redundancy in the system structure. Experimental verification shows that during the high-flow-rate pumping stage (such as the initial stage of pumping), the gas pressure changes rapidly along the inter-stage gradient. Often, only a single-stage chamber can reach the preset exhaust pressure, and the amount of gas discharged in this stage accounts for more than 90% of the total exhaust volume in this stage. The pressure relief ports of the remaining stages remain closed for a long time due to insufficient pressure, with only a few upstream stages occasionally opening briefly. In reality, they do not play an effective pressure relief role, but instead increase the complexity of the pump structure and manufacturing cost.

[0006] On the other hand, in this design, the exhaust ports of each stage of the pressure relief system are located on the upper side of the pump body's air inlet, while the exhaust port of the final stage of the pump is located on the lower side. The two positions span the entire pump body and are quite far apart. This requires an additional T-joint to collect the discharged gas, which not only increases the complexity of the pipeline connection and the risk of leakage, but may also lead to increased exhaust resistance due to excessively long pipelines, affecting exhaust efficiency.

[0007] In response to the core deficiencies of the existing technologies, this design proposes a precise improvement scheme. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a vacuum pump and its operating method based on a pre-depressurization and unidirectional exhaust structure. A single pressure relief port is set only in the critical stage with the largest exhaust volume during the initial pumping phase. Experimental data is used to identify the chamber with the highest pressure compliance frequency as the pressure relief node, avoiding the structural redundancy of "full-stage valve arrangement" while ensuring maximum pressure relief efficiency. Furthermore, the pressure relief port and the final-stage exhaust port are integrated into the same structural component, thus avoiding the problem in existing technologies where the pressure relief port and the final-stage exhaust port are located on the upper and lower sides of the pump body, requiring additional T-joints to collect the exhaust gas. This simplifies the structure, reduces exhaust resistance, and improves exhaust efficiency.

[0009] Meanwhile, a valve ball is added to the final exhaust channel. With the reverse shut-off characteristic of the one-way valve, the gas backflow path between the exhaust pipe and the final chamber can be effectively blocked. This prevents the outside atmosphere from flowing back through the exhaust port after the vacuum pump stops unexpectedly, and prevents the airflow from carrying impurities into the pump body and the connected process chamber, thereby ensuring the cleanliness and process stability of the vacuum system.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a vacuum pump based on an early pressure relief and unidirectional exhaust structure. The pump body includes an intake component, an upper housing, a rotor assembly, a lower housing, and an exhaust component arranged sequentially from top to bottom. An HV support component and an LV support component are respectively arranged on both sides of the rotor assembly. The HV support component includes a gearbox inside, and the LV support component includes a drive motor inside. The exhaust component is provided with two sets of exhaust branches, including a first exhaust branch located below any intermediate stage chamber of the lower housing, and a second exhaust branch located below the final stage of the lower housing.

[0011] The rotor assembly consists of two rotors, both coaxial and arranged with several Roots rotor blades in sequence. Each blade has the same profile and its thickness decreases sequentially from intake to exhaust.

[0012] The exhaust component, from top to bottom, includes a sealing partition, an exhaust main board, and a main board sealing plate. The sealing partition is provided with intermediate-stage vent holes and final-stage vent holes. The exhaust main board includes two sets of exhaust branches with identical structures. Each exhaust branch includes a vertical exhaust chamber, a horizontal exhaust chamber, and a valve chamber. The vertical exhaust chamber runs longitudinally through the exhaust main board. The upper end of the vertical exhaust chamber is aligned with and connected to the intermediate-stage vent holes and the final-stage vent holes, respectively. The lower end of the vertical exhaust chamber is connected to the horizontal exhaust chamber, and the horizontal exhaust chamber is connected to the valve chamber.

[0013] The valve cavity is equipped with a valve ball. The valve cavity includes a front cavity, a valve port, and a guide cavity connected in sequence. The front cavity is connected to the transverse exhaust cavity. Gas expands in the front cavity. The valve port includes a contraction sealing section and an exhaust expansion section. The port of the contraction sealing section is set as a conical surface that cooperates with the valve ball to control the up and down movement of the valve ball inside the guide cavity. The exhaust expansion section is set as an annular groove and is connected to the guide cavity.

[0014] When the gas pressure in the current chamber has not reached the preset exhaust pressure, the valve ball is in its initial state, blocking gas discharge; when the gas pressure in the current chamber reaches the preset exhaust pressure, the upward thrust of the pressure in the front chamber on the valve ball is greater than the downward gravity of the valve ball itself, opening the valve port, and the gas pushes the valve ball upward along the guide chamber.

[0015] One end of the exhaust branch is connected to the exhaust expansion section of the guide cavity and the valve cavity, and the other end is connected to the gas collection cavity. It is used to guide the gas discharged from the valve port to the gas collection cavity and finally discharge it through the main exhaust cavity. The outlet of the main exhaust cavity is connected to the exhaust pipe.

[0016] The valve ball is spherical and includes an outer shell layer, a support layer, and filling particles. The support layer is located inside the outer shell layer, and the filling particles are filled inside the support layer.

[0017] The outer shell layer is made of wear-resistant and high-temperature resistant rubber material.

[0018] The mainboard sealing plate seals the lower open areas of the two sets of exhaust branches to form two independent exhaust channels.

[0019] Secondly, the present invention provides a working method for a vacuum pump based on a pre-depressurization and unidirectional exhaust structure. In the initial stage of pumping, there is a lot of gas in the vacuum pump, which reaches the preset pressure of the first exhaust branch of the intermediate stage of the pump body. The gas is depressurized in advance through the first exhaust branch. As pumping proceeds, the amount of gas in the pump body decreases and does not reach the preset pressure of the intermediate stage of the pump body. The gas is depressurized from the second exhaust branch of the final stage of the pump body.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a vacuum pump and its operating method based on a pre-depressurization and unidirectional exhaust structure. By adding an extra exhaust channel in the intermediate stage as a pre-depressurization exhaust channel, the gas, which has already reached a preset exhaust pressure in the initial stage of pumping, is discharged from the working chamber of the vacuum pump rotor through the pressure relief port, taking advantage of the easily compressible characteristics of the large flow of gas during the initial stage of pumping. This eliminates the need for the gas to continue being compressed through subsequent stages as in traditional vacuum pumps with only tail-end exhaust, thus improving the pumping efficiency of the vacuum pump and reducing energy waste, achieving energy saving. It also breaks through the crude "uniformly distributed pressure relief ports" model of existing technologies, achieving precise matching between the pre-depressurization channel and the dynamic pressure characteristics of the multi-stage pump, significantly improving pumping efficiency while ensuring system reliability. By integrating the pre-depressurization channel and the conventional exhaust channel into the same exhaust component, a modular design with dual pathways is achieved. Specifically, the two channels share the gas collection chamber, the main exhaust chamber, and the exhaust pipe. Independent airflow paths are formed by the partitioned sealing of the sealing partition and the main board sealing plate, avoiding gas interference between channels and reducing redundant connecting pipes and support structures in traditional discrete designs. This improves the compactness of the vacuum pump structure, while reducing assembly difficulty and the risk of seal failure, providing greater flexibility for the installation and deployment of equipment in confined spaces.

[0021] Furthermore, both sets of exhaust channels of the pump are equipped with valve ports and corresponding valve balls. On the one hand, the valve ball can automatically determine whether the gas pressure in the front chamber has reached the preset pressure value, and maintain the pressure of the gas that has not reached the preset pressure value and cut off the backflow of gas to avoid additional energy consumption and reduce the pump's operating power consumption. In the initial stage of gas extraction, the gas pushes open the valve ball at the pre-pressure relief channel and is mainly discharged through the pre-pressure relief channel; in the normal gas extraction stage, the gas pressure at the pre-pressure relief channel has not reached the preset pressure, and under the combined action of the pressure difference and the gravity of the valve ball, the valve ball and the valve port are in contact, and the pre-pressure relief channel is closed.

[0022] Furthermore, the valve ball has a multi-layered structure. The outermost rubber shell layer improves the sealing performance of the pressure relief port and prevents direct collision between the metal of the support layer and the metal of the pressure relief port. The internal filling material is granular, which facilitates replenishment and adjustment of the valve ball's mass to achieve the designed mass, and can also reduce impact vibration and noise. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the vacuum pump of the present invention; Figure 2 This is an exploded view of the vacuum pump of the present invention; Figure 3 This is an exploded view of the exhaust component of the vacuum version of the present invention; Figure 4 This is a cross-sectional view of the vacuum pump of the present invention; Figure 5 This is a half-sectional view of the exhaust component of the vacuum pump of the present invention; Figure 6 This is a cross-sectional view of the valve ball of the vacuum pump of the present invention; Explanation of reference numerals in the figure: 1. Intake component; 11. Intake port; 2. Upper housing; 3. Rotor assembly; 4. Lower housing; 5. Exhaust component; 51. Sealing partition; 511. Intermediate stage vent; 512. Final stage vent; 52. Exhaust main plate; 521. Vertical exhaust chamber; 5211. First vertical exhaust chamber; 5212. Second vertical exhaust chamber; 522. Horizontal exhaust chamber; 5221. First horizontal exhaust chamber; 5222. Second horizontal exhaust chamber; 523. Valve chamber; 5231. Front chamber; 5232. Valve port; 5 2321. Shrink sealing section; 52322. Exhaust expansion section; 5233. Guide cavity; 5234. First valve cavity; 5235. Second valve cavity; 524. Exhaust branch; 5241. First exhaust branch; 5242. Second exhaust branch; 525. Gas collection cavity; 526. Main exhaust cavity; 53. Main board sealing plate; 54. Exhaust pipe; 55. Valve ball; 551. Outer shell layer; 552. Support layer; 553. Filler particles; 6. HV support component; 7. LV support component; 8. Heat dissipation component; 81. Heat dissipation fins. Detailed Implementation

[0024] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0025] Example 1 A vacuum pump based on a pre-depressurization and unidirectional exhaust structure has the following structural components: like Figures 1-2 As shown, a vacuum pump based on a pre-depressurization and unidirectional exhaust structure includes, from top to bottom, an intake component 1, an upper housing 2, a rotor assembly 3, a lower housing 4, and an exhaust component 5. HV support components 6 and LV support components 7 are respectively provided on the left and right sides of the rotor assembly 3, and heat dissipation components 8 are provided on both the front and rear sides of the rotor assembly 3.

[0026] The intake component 1 is a standard-sized vacuum flange, serving as the intake channel for the entire pump; the exhaust component 5 is equipped with an exhaust port, serving as the exhaust channel for the entire pump; the HV support component 6 includes a gearbox containing a pair of timing synchronous gears for power transmission and ensuring phase relationship between the rotor groups 3, and two sets of bearings and shaft end sealing elements are located within the HV support component 6; the LV support component 7 includes a motor housing containing a drive motor that generates power, and two additional sets of bearings and shaft end sealing elements are located within the LV support component 7; to facilitate heat dissipation, heat dissipation fins 81 are provided on the intake component 1, the exhaust component 5, and the housing heat dissipation component 8. The heat dissipation fins 81 are arranged in the same direction as the axis of the rotor group 3, which facilitates the removal of heat when the gas flows along the axial direction, thereby improving heat dissipation efficiency.

[0027] like Figure 2 As shown, rotor group 3 consists of two rotors, both of which are coaxial and have multiple Roots rotor blades arranged sequentially. Each blade has the same profile and its thickness decreases sequentially from intake to exhaust.

[0028] Furthermore, the upper housing 2 and lower housing 4 each have corresponding chambers for accommodating multiple Roots rotor blades. The upper part of the first-stage chamber is connected to the intake component; each stage chamber has connecting air passages on its outer side, connecting to the lower part (chamber exhaust port) of each stage chamber except the final stage. The discharged gas is transported through the connecting air passages to the upper part (next stage chamber intake port) of the next stage chamber, so that each stage chamber is connected in series; the lower part of the final-stage chamber is connected to a set of gas discharge channels of the exhaust component 5. Accordingly, the volume of each chamber decreases sequentially from intake to exhaust, compressing the incoming gas sequentially to reach a preset pressure for discharge. Additionally, the lower part of a selected first-stage chamber is also connected to another set of gas discharge channels of the exhaust component 5.

[0029] like Figures 3-5 As shown, the exhaust component 5 includes, from top to bottom, a sealing partition 51, an exhaust main board 52 and a main board sealing plate 53. Two valve balls 55 are provided above the exhaust main board 52, and an exhaust pipe 54 is connected to the exhaust port of the exhaust main board 52.

[0030] The sealing baffle 51 is used to seal each stage of the lower housing 4 to prevent gas leakage from the pump to the atmosphere and to prevent leakage between stages. It is provided with an intermediate stage vent 511 and a final stage vent 512. The final stage vent 512 is located below the final stage and is connected to the gas discharge channel used during normal operation. The intermediate stage vent 511 is located below a certain intermediate stage chamber of the pump body and is connected to the gas pre-pressure relief channel used to pre-depressurize the gas by reaching a preset pressure in the early stage of pumping.

[0031] The exhaust main board 52 includes: two sets of gas discharge channels, two sets of exhaust branches 524, a gas collection chamber 525, and a main exhaust chamber 526. The two sets of gas discharge channels have identical structures, each including: a vertical exhaust chamber 521, a horizontal exhaust chamber 522, and a valve chamber 523. The vertical exhaust chamber 521 is a vertically arranged channel that penetrates the exhaust main board 52, and its upper end is aligned with and connected to the vent holes of the sealing partition 51. The horizontal exhaust chamber 522 is horizontally arranged and connected to the lower end of the vertical exhaust chamber 521.

[0032] The two sets of gas discharge channels, the second vertical exhaust chamber 5212 is connected to the final vent 512 at the end of the sealing partition 51, which is the conventional gas discharge channel used in normal operation; the first vertical exhaust chamber 5211 is connected to the intermediate vent 511 of the sealing partition 51, which is the pre-pressure relief channel for the gas that has reached the preset pressure in advance at the beginning of the gas extraction, and is the large flow gas in the initial stage of the gas extraction.

[0033] Valve chamber 523 serves as the discharge channel when gas reaches a preset pressure. It comprises a front chamber 5231, a valve port 5232, and a guide chamber 5233 connected in sequence. The front chamber 5231 is connected to the transverse exhaust chamber 522, allowing gas to fully expand within it. The valve port 5232 consists of a contraction sealing section 52321 and an exhaust expansion section 52322. The contraction sealing section 52321 is a relatively small-diameter through-hole, with its upper edge configured as a conical surface (equivalent to a gas collector nozzle) that mates with the valve ball 55. When the gas pressure in the front chamber 5231 has not reached the preset exhaust pressure, the valve ball 55 remains in its initial state, blocking gas discharge. The exhaust expansion section 52322 is a relatively large-diameter annular groove, which increases the exhaust area and reduces airflow resistance during exhaust, facilitating gas flow. The guide chamber 5233 is a cylindrical space used to accommodate the valve ball 55 and control its movement range, further assisting the valve port 5232 in gas discharge. Furthermore, when the valve ball 55 falls, the valve ball 55 and the contraction sealing section 52321 of the valve port 5232 come into contact and seal under the combined action of gravity and external gas pressure, blocking the external gas backflow channel.

[0034] The exhaust branch 524 is connected at one end to the exhaust expansion section 52322 of the guide cavity 5233 and the valve cavity 523, and at the other end to the gas collection cavity 525. It is used to guide the gas discharged from the valve port 5232 to the gas collection cavity 525, and finally discharge it through the main exhaust cavity 526.

[0035] The main board sealing plate 53 is used to seal the lower open area of ​​the two sets of exhaust branches 524 to form two independent sets of exhaust channels.

[0036] The exhaust pipe 54 is fixed to the exhaust main plate 52, and one end of its internal channel is connected to the main exhaust chamber 526 of the exhaust main plate 52 to discharge gas outside the pump. The other end of the exhaust pipe 54 is an exhaust port, which is a standard-sized vacuum flange for easy connection to other subsequent equipment.

[0037] like Figure 6 As shown, the valve ball 55 is spherical in shape and can move up and down within the guide cavity 5233 under constraint. It consists of three parts: an outer shell layer 551, a support layer 552, and filling particles 553. The outer shell layer 551 is located on the outermost layer and mainly serves a sealing function, ensuring good sealing performance throughout the entire service life of the vacuum pump. The support layer 552 is located inside the outer shell layer 551 and is a hollow metal shell that provides support. It is tightly fixed to the outer shell layer 551 and its main function is to maintain the shape of the valve ball 55. The filling particles 553 are granular fillers (such as quartz sand or metal particles), which facilitate the replenishment and adjustment of the valve ball 55's mass to achieve the designed mass, and the interaction between the particles can reduce impact vibration and lower noise.

[0038] Preferably, the outer shell layer 551 is made of wear-resistant and high-temperature resistant rubber, such as nitrile rubber, polyacrylate rubber and fluororubber; when the valve ball 55 falls and collides with the sealing surface of the valve port 5232, it can effectively reduce noise.

[0039] Example 2 A vacuum pump based on a pre-depressurization and unidirectional exhaust structure operates as follows: I. Main gas compression and early pressure relief emission paths in the initial stage of gas extraction: 1. Inhalation: Gas enters the upper part of the first stage through the air inlet 11 and the air intake component 1; 2. Compression: The gas is compressed through the first stage and part of the intermediate stage (the lower part of each stage in the pump is connected to the upper part of the next stage) to reach the preset exhaust pressure; 3. Pre-depressurization: Gas enters the pre-depressurization channel (first exhaust branch 5241) through the intermediate stage vent 511 on the intermediate stage sealing partition 51 below the intermediate stage, and enters the front chamber 5231 of the first valve chamber 5234 in sequence through the first vertical exhaust chamber 5211 and the first horizontal exhaust chamber 5221. Since the gas pressure has reached the preset pressure, the upward thrust of the pressure in the front chamber 5231 on the valve ball 55 is greater than the downward gravity of the valve ball 55 itself. The gas pushes the valve ball 55 to move upward along the guide chamber 5233, opening the valve port 5232. The gas enters the corresponding first exhaust branch 5241 through the contraction sealing section 52321 and the exhaust expansion section 52322.

[0040] 4. Exhaust: Gas enters the gas collection chamber 525 through the first exhaust branch 5241, and finally enters the exhaust pipe 54 through the main exhaust chamber 526 to reach the exhaust port.

[0041] II. Gas Compression and Emission Paths in the Conventional Stage: 1. Inhalation; gas enters the upper part of the first stage through the air inlet and air intake component 1; 2. Compression: The gas is compressed stage by stage, through the first stage, intermediate stage, and final stage. It enters the conventional discharge channel through the final stage vent 512 of the sealing baffle 51 below the final stage, and then passes through the second vertical exhaust chamber 5212 and the second horizontal exhaust chamber 5222 before entering the second valve chamber 5235. As the pumping progresses, the gas in the pump body decreases. Because the pressure in the pre-depressurization channel located in the intermediate stage has not reached the preset value, the gas cannot pass through here.

[0042] 3. Pressure holding and pressure relief: When the gas pressure does not reach the preset pressure, the valve ball 55 falls on the contraction sealing section 52321 of the valve port 5232, preventing the external gas at the tail from flowing back into the pump body; when the gas pressure reaches the preset pressure, the gas pushes open the valve ball 55 and is discharged from the valve port 5232.

[0043] 4. Exhaust: Gas enters the gas collection chamber 525 through the second exhaust branch 5242, and finally enters the exhaust pipe 54 through the main exhaust chamber 526 to reach the exhaust port.

[0044] This patent describes a multi-stage compression Roots vacuum pump, primarily designed for the initial stage of pumping. In contrast to traditional single-exhaust pumps, where the gas has already reached the preset exhaust pressure in the intermediate stage, the single-outlet limitation forces it to continue through subsequent stages, resulting in overcompression, energy waste, and excessively high pump body temperature. This patent addresses this by conducting experiments under specific operating conditions to identify the most suitable chamber for early pressure relief and exhaust under these conditions. An additional exhaust channel is provided within this chamber as an early pressure relief and exhaust channel.

[0045] Furthermore, since both sets of exhaust channels have valve ports 5232 with reverse shut-off function, this function is achieved through the fit between the valve ball 55 and the pressure relief port contraction sealing section 52321. When the pressure in the front chamber is insufficient for the preset exhaust pressure, the valve ball 55 seals against the conical surface, preventing gas backflow. Therefore, the gas pressure flowing to the valve port 5232 is allowed to be slightly lower than the preset pressure. The gas reaching the valve port 5232 but not reaching the preset pressure value collects in the front chamber 5231 of the valve port 5232. As the vacuum pump rotor assembly 3 continues to operate and generates periodic exhaust, the gas collected in the front chamber 5231 gradually increases. Until the preset exhaust pressure is reached, the gas pushes open the valve ball 55 to exhaust.

[0046] Specifically, the device used to determine whether the gas pressure has reached the preset value is the valve ball 55, and its main metric is the mass of the valve ball 55. A rough calculation method is as follows: The theoretical mass (kg) of valve ball 55 = the cross-sectional area (m²) of the constriction sealing section 52321.2 * (Preset pressure (Pa) - Exhaust pressure (Pa)); In actual use, in order to ensure the best pressure relief and reverse shut-off functions, and taking into account the sealing and venting states, the actual weight of the valve ball 55 is slightly heavier than the theoretical weight. Preferably, the actual weight of the valve ball 55 is 7-10% higher than the theoretical weight.

[0047] Preferably, the mass of the valve ball 55 of the valve port 5232 of the pre-depressurization exhaust channel can be set to be slightly higher than that of the valve ball 55 of the conventional exhaust channel port. This ensures that the valve ball 55 moves with a small amplitude and has low exhaust noise during the high flow rate of the initial stage of the exhaust.

[0048] In the exhaust main board 52, the two sets of gas discharge channels are independent of each other and are connected to the final stage and the early pressure relief stage respectively. Through their respective internal channels, they enter their respective exhaust branches 524 through valve chambers 523 with the same structure but different functions, and are collected in the gas collection chamber 525 and finally discharged through a total exhaust chamber 526.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure, characterized in that, The pump body includes an intake component (1), an upper housing (2), a rotor assembly (3), a lower housing (4), and an exhaust component (5) arranged sequentially from top to bottom. An HV support component (6) and an LV support component (7) are respectively arranged on both sides of the rotor assembly (3). The HV support component (6) includes a gearbox inside, and the LV support component (7) includes a drive motor inside. The exhaust component (5) is provided with two sets of exhaust branches (524). The two sets of exhaust branches (524) include a first exhaust branch (5241) located below any intermediate stage chamber of the lower housing (4) and a second exhaust branch (5242) located below the final stage of the lower housing (4).

2. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 1, characterized in that, The rotor assembly (3) consists of two rotors, both of which are coaxial and have several Roots rotor blades arranged in sequence. Each blade has the same profile and its thickness decreases sequentially from intake to exhaust.

3. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 1, characterized in that, The exhaust component (5) includes, from top to bottom, a sealing partition (51), an exhaust main board (52), and a main board sealing plate (53). The sealing partition (51) is provided with an intermediate stage vent (511) and a final stage vent (512). The exhaust main board (52) includes two sets of exhaust branches (524) with the same structure. The exhaust branch (524) includes a vertical exhaust chamber (521), a horizontal exhaust chamber (522), and a valve chamber (523). The vertical exhaust chamber (521) runs longitudinally through the exhaust main board (52). The upper end of the vertical exhaust chamber (521) is aligned with and connected to the intermediate stage vent (511) and the final stage vent (512), respectively. The lower end of the vertical exhaust chamber (521) is connected to the horizontal exhaust chamber (522). The horizontal exhaust chamber (522) is connected to the valve chamber (523).

4. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 3, characterized in that, The valve cavity (523) is provided with a valve ball (55). The valve cavity (523) includes a front cavity (5231), a valve port (5232), and a guide cavity (5233) connected in sequence. The front cavity (5231) is connected to the transverse exhaust cavity (522). Gas expands in the front cavity (5231). The valve port (5232) includes a contraction sealing section (52321) and an exhaust expansion section (52322). The port of the contraction sealing section (52321) is set as a conical surface that cooperates with the valve ball (55) to control the up and down movement of the valve ball (55) inside the guide cavity (5233). The exhaust expansion section (52322) is set as an annular groove and is connected to the guide cavity (5233).

5. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 4, characterized in that, When the gas pressure in the current chamber (5231) has not reached the preset exhaust pressure, the valve ball (55) is in the initial state, blocking gas discharge; when the gas pressure in the current chamber (5231) reaches the preset exhaust pressure, the upward thrust of the pressure in the front chamber (5231) on the valve ball (55) is greater than the downward gravity of the valve ball (55), opening the valve port (5232), and the gas pushes the valve ball (55) to move upward along the guide chamber (5233).

6. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 4, characterized in that, One end of the exhaust branch (524) is connected to the exhaust expansion section (52322) of the guide cavity (5233) and the valve cavity (523), and the other end is connected to the gas collection cavity (525). It is used to guide the gas discharged from the valve port (5232) to the gas collection cavity (525) and finally discharge it through the main exhaust cavity (526). The outlet of the main exhaust cavity (526) is connected to the exhaust pipe (54).

7. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 4, characterized in that, The valve ball (55) is spherical and includes an outer shell layer (551), a support layer (552) and filling particles (553). The support layer (552) is located inside the outer shell layer (551), and the filling particles (553) are filled inside the support layer (552).

8. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 7, characterized in that, The outer shell layer (551) is made of wear-resistant and high-temperature resistant rubber material.

9. A vacuum pump based on a pre-depressurization and unidirectional exhaust structure according to claim 3, characterized in that, The main board sealing plate (53) seals the lower open area of ​​the two sets of exhaust branches (524) to form two independent exhaust channels.

10. A method for operating a vacuum pump based on an early pressure relief and unidirectional exhaust structure, based on a vacuum pump based on an early pressure relief and unidirectional exhaust structure as described in any one of claims 1 to 9, characterized in that, In the initial stage of pumping, there is a lot of gas in the vacuum pump, which reaches the preset pressure of the first exhaust branch (5241) of the intermediate stage of the pump body. The gas is depressurized in advance through the first exhaust branch (5241). As pumping proceeds, the amount of gas in the pump body decreases and does not reach the preset pressure of the intermediate stage of the pump body. The gas is depressurized through the second exhaust branch (5242) of the final stage of the pump body.

Images