Vacuum pump sealing system and method of controlling the same

Abstract

The application relates to the technical field of vacuum pumps, in particular to a vacuum pump sealing system and a control method thereof. A shaft head pressure regulating air channel is arranged on a rotor shaft and communicates with a middle cavity of a suction end sealing assembly and a suction end lubricating cavity, so that the pressure difference on both sides of a one-way outer sealing ring is reduced, the sealing performance between the one-way outer sealing ring and the rotor shaft is ensured, and the abrasion between the one-way outer sealing ring and the rotor shaft is reduced. A suction end pressure regulating air channel which communicates with the middle cavity is arranged on a pump body, an air channel of an air source assembly is communicated with the suction end pressure regulating air channel, the air flow output of the air source assembly is controlled according to the air pressure change of a rotor cavity suction port detected by an air pressure detection device, the air pressure of the middle cavity is adjusted according to the air pressure of the rotor cavity suction port, the air pressure difference between the rotor cavity suction port and the middle cavity is reduced, the pressure difference borne by a one-way inner sealing ring is reduced, the sealing performance of the one-way inner sealing ring is ensured, and the abrasion between the one-way inner sealing ring and the rotor shaft is reduced.

Description

Technical Field

[0001] This application relates to the field of vacuum pump technology, specifically to a vacuum pump sealing system and its control method. Background Technology

[0002] In a vacuum pump, the rotor shaft has two shaft extensions located at the intake end and the exhaust end, respectively. Each shaft extension extends from the rotor cavity into the lubrication cavity at the corresponding end. A sealing structure is required between the rotor cavity and the lubrication cavity at the intake end, and between the rotor cavity and the lubrication cavity at the exhaust end, to ensure the normal operation of the vacuum pump.

[0003] In the intake end sealing structure, two one-way lip seals in opposite directions are usually used to contact the rotor shaft to achieve the sealing between the rotor cavity and the intake end lubrication cavity. The one closer to the rotor cavity is the inner sealing ring, which is used to prevent process gas or particles from entering the bearing or lubrication cavity. The one closer to the bearing housing is the outer sealing ring, which is used to prevent lubricating oil in the lubrication cavity from entering the rotor cavity.

[0004] During the operation of a vacuum pump, when the air pressure at the rotor cavity intake port is greater than the air pressure in the middle area between the inner and outer sealing rings, the pressure on the inner sealing ring increases, and the friction between the inner sealing ring and the rotor shaft increases, which leads to accelerated wear of the inner sealing ring. When the air pressure in the middle area between the inner and outer sealing rings is less than the air pressure in the lubrication chamber at the intake end, the pressure on the outer sealing ring increases, and the friction between the outer sealing ring and the rotor shaft increases, which leads to accelerated wear of the outer sealing ring. Summary of the Invention

[0005] This application provides a vacuum pump sealing system and its control method to solve the technical problem of accelerated wear of the inner and outer sealing rings at the suction end of the vacuum pump.

[0006] According to the first aspect, one embodiment provides a vacuum pump sealing system, including a vacuum pump, a gas source assembly, a gas pressure detection device, and a control device;

[0007] The vacuum pump includes a pump body, a rotor shaft, and an intake end sealing assembly. The pump body has a rotor cavity and an intake end lubrication cavity. The rotor cavity has an intake port and an exhaust port. The rotor shaft is rotatably mounted in the pump body. The intake end sealing assembly is sealed between the pump body and the rotor shaft to separate the rotor cavity and the intake end lubrication cavity.

[0008] The suction end sealing assembly includes a one-way inner sealing ring and a one-way outer sealing ring. The suction end sealing assembly and the rotor shaft enclose an intermediate cavity between the one-way inner sealing ring and the one-way outer sealing ring. The pump body has a suction end pressure regulating air passage, which connects the intermediate cavity with the air passage of the air source assembly. The rotor shaft has a shaft head pressure regulating air passage, which connects the intermediate cavity with the suction end lubrication cavity.

[0009] The air pressure detection device is used to detect the air pressure at the air inlet. The control device is electrically connected to both the air pressure detection device and the air source assembly. The control device can control the airflow output of the air source assembly based on the detection result of the air pressure detection device.

[0010] In one optional embodiment, along the axial direction of the rotor shaft, the one-way inner sealing ring is located between the rotor cavity and the one-way outer sealing ring, and the one-way inner sealing ring is used to achieve a seal from the rotor cavity to the suction end lubrication cavity; the one-way outer sealing ring is located between the one-way inner sealing ring and the suction end lubrication cavity, and the one-way outer sealing ring is used to achieve a seal from the suction end lubrication cavity to the rotor cavity; both the one-way inner sealing ring and the one-way outer sealing ring seal the rotor shaft.

[0011] In an optional embodiment, the intake end sealing assembly further includes a connecting ring located radially outside the one-way inner sealing ring and the one-way outer sealing ring. The connecting ring, the one-way inner sealing ring, the one-way outer sealing ring, and the rotor shaft enclose the intermediate cavity. The connecting ring has an intermediate channel connecting the intermediate cavity and the intake end pressure regulating air passage.

[0012] The connecting ring includes a first ring body and a second ring body arranged axially on the rotor shaft at intervals. The one-way inner sealing ring is connected to the first ring body, and the one-way outer sealing ring is connected to the second ring body. The intermediate channel is located between the first ring body and the second ring body; or, the connecting ring, the one-way inner sealing ring, and the one-way outer sealing ring are integrally formed.

[0013] In one alternative embodiment, the air pressure detection device is mounted on the pump body and is located at the air inlet.

[0014] In one optional embodiment, the air source assembly includes an air source and an air valve, the air valve being electrically connected to the control device; the air passage of the air source is connected to the intermediate cavity through the pressure regulating air passage at the intake end, and the air valve is used to control the airflow output of the air source;

[0015] Alternatively, the air source assembly includes an air source with an adjustable airflow output, the air source being electrically connected to the control device, and the control device being able to control the airflow output of the air source.

[0016] In an optional embodiment, the pump body further includes an exhaust end lubrication chamber, and the vacuum pump includes an exhaust end sealing assembly. The exhaust end sealing assembly seals the pump body and the rotor shaft respectively to separate the rotor cavity from the exhaust end lubrication chamber. The exhaust end sealing assembly and the rotor shaft enclose an intermediate sealing cavity. The gas passage of the gas source is also connected to the intermediate sealing cavity for supplying gas to the intermediate sealing cavity.

[0017] In one alternative embodiment, the vacuum pump sealing system includes a pressure sensor electrically connected to the control device, the pressure sensor being used to detect the pressure in the intermediate cavity.

[0018] According to a second aspect, one embodiment provides a control method for a vacuum pump sealing system as described in any of the preceding claims, comprising:

[0019] When the air pressure detection device detects an increase in air pressure at the air inlet, the control device controls the air source assembly to increase the airflow output;

[0020] When the air pressure detection device detects a decrease in air pressure at the air inlet, the control device controls the air source component to reduce or stop the airflow output.

[0021] In one optional embodiment, when the air pressure detection device detects that the air pressure at the air inlet has decreased to a limit value, the control device controls the air source component to stop airflow output.

[0022] In one optional embodiment, the vacuum pump sealing system includes a pressure sensor electrically connected to the control device, the pressure sensor being used to detect the pressure in the intermediate cavity;

[0023] The control method of the vacuum pump sealing system further includes: when the control device controls the airflow output of the gas source component, it controls the air pressure of the intermediate cavity to be greater than the air pressure of the air inlet and less than the sum of the air pressure of the air inlet and the sealing pressure of the one-way inner sealing ring.

[0024] In an optional embodiment, the pump body further has an exhaust end lubrication chamber, the vacuum pump includes an exhaust end sealing assembly, the exhaust end sealing assembly seals the pump body and the rotor shaft respectively to separate the rotor cavity from the exhaust end lubrication chamber, the exhaust end sealing assembly and the rotor shaft enclose an intermediate sealing chamber; the gas source assembly includes a gas source, the gas passage of the gas source is also in communication with the intermediate sealing chamber;

[0025] The control method for the vacuum pump sealing system also includes:

[0026] The gas source supplies gas to the intermediate sealing cavity, controlling the gas pressure in the intermediate sealing cavity to be higher than the gas pressure in the exhaust end lubrication cavity, and also higher than the gas pressure at the exhaust port.

[0027] According to the vacuum pump sealing system and control method of the above embodiments, a shaft head pressure regulating air passage is provided on the rotor shaft, connecting the suction end lubrication chamber and the intermediate cavity in the suction end sealing assembly, so that the air pressure in the intermediate cavity and the suction end lubrication chamber are equal, thereby reducing the pressure difference on the one-way outer sealing ring. While ensuring the sealing performance between the one-way outer sealing ring and the rotor shaft, the wear between the one-way outer sealing ring and the rotor shaft is reduced. Furthermore, a suction end pressure regulating air passage is provided on the pump body, connecting the air passage of the air source assembly and the suction end pressure regulating air passage. The airflow output of the air source assembly is controlled according to the air pressure change at the rotor cavity suction port detected by the air pressure detection device, thereby adjusting the air pressure in the intermediate cavity according to the air pressure at the rotor cavity suction port, so as to reduce the air pressure difference between the rotor cavity suction port and the intermediate cavity, reduce the pressure difference on the one-way inner sealing ring, and reduce the wear between the one-way inner sealing ring and the rotor shaft while ensuring the sealing performance of the one-way inner sealing ring. Attached Figure Description

[0028] Figure 1 This is a partial structural schematic diagram of a vacuum pump sealing system according to an embodiment of this application;

[0029] Figure 2 This is a schematic diagram of the structure of an intake end sealing assembly according to an embodiment of this application;

[0030] Figure 3 This is a schematic diagram of the overall structure of a vacuum pump sealing system according to an embodiment of this application.

[0031] In the diagram: 1. Pump body; 11. Suction end lubrication chamber; 12. Rotor chamber; 121. Suction port; 122. Exhaust port; 13. Exhaust end lubrication chamber; 14. Suction end mounting base; 141. Suction end pressure regulating air passage; 2. Rotor shaft; 21. Shaft head pressure regulating air passage; 211. First pressure regulating air passage; 212. Second pressure regulating air passage; 3. Suction end sealing assembly; 31. One-way inner sealing ring; 32. One-way outer sealing ring; 33. Connecting ring; 331. Intermediate channel; 34. Intermediate cavity; 5. Exhaust end sealing assembly; 6. Air source; 7. Air valve; 8. Air pressure detection device; 9. Control device. Detailed Implementation

[0032] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0033] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments, and the operational steps involved in each embodiment can also be rearranged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for clearly describing a particular embodiment and do not imply that they represent the necessary components and / or order.

[0034] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0035] This application provides a vacuum pump sealing system. Please refer to [link / reference]. Figures 1 to 3 The vacuum pump includes a pump body 1 and a rotor shaft 2 rotatably mounted in the pump body 1. The pump body 1 has an intake end and an exhaust end, which are arranged at both ends of the rotor shaft 2. The pump body 1 has a rotor cavity 12, an intake end lubrication cavity 11 and an exhaust end lubrication cavity 13. The intake end lubrication cavity 11 is located at the intake end, and the exhaust end lubrication cavity 13 is located at the exhaust end.

[0036] The rotor shaft 2 is rotatably mounted in the pump body 1 via an intake bearing (not shown in the figure) and an exhaust bearing (not shown in the figure). The intake bearing is located in the intake lubrication chamber 11 to ensure normal operation of the intake bearing. The intake sealing assembly 3 is installed between the pump body 1 and the rotor shaft 2. The intake sealing assembly 3 is located in the axial direction of the rotor shaft 2 between the rotor cavity 12 and the intake lubrication chamber 11 to separate the rotor cavity 12 and the intake lubrication chamber 11. The exhaust bearing is located in the exhaust lubrication chamber 13 to ensure normal operation of the exhaust bearing. The exhaust sealing assembly 5 is installed between the pump body 1 and the rotor shaft 2. The exhaust sealing assembly 5 is located in the axial direction of the rotor shaft 2 between the rotor cavity 12 and the exhaust lubrication chamber 13 to separate the rotor cavity 12 and the exhaust lubrication chamber 13.

[0037] In some embodiments, the intake end sealing assembly 3 includes a one-way inner sealing ring 31 and a one-way outer sealing ring 32. Both the one-way inner sealing ring 31 and the one-way outer sealing ring 32 can be one-way lip seals. Of course, in other embodiments, they can also be one-way sealing rings of other structures besides lip seals. In the axial direction of the rotor shaft 2, the one-way inner sealing ring 31 is located between the rotor cavity 12 and the one-way outer sealing ring 32, and is used to achieve a seal from the rotor cavity 12 to the intake end lubrication cavity 11; the one-way outer sealing ring 32 is located between the one-way inner sealing ring 31 and the intake end lubrication cavity 11, and is used to achieve a seal from the intake end lubrication cavity 11 to the rotor cavity 12. Both the one-way inner sealing ring 31 and the one-way outer sealing ring 32 seal the rotor shaft 2.

[0038] In one embodiment, please refer to Figure 1 and Figure 2 Both the one-way inner sealing ring 31 and the one-way outer sealing ring 32 have arc-shaped cross-sections. In the axial direction of the rotor shaft 2, the radial inner end of the one-way inner sealing ring 31 is located between the radial outer end of the one-way inner sealing ring 31 and the rotor cavity 12, and the radial inner end of the one-way outer sealing ring 32 is located between the radial outer end of the one-way outer sealing ring 32 and the suction end lubrication cavity 11. Both the one-way inner sealing ring 31 and the one-way outer sealing ring 32 can be made of rubber material. The radial inner end of the one-way inner sealing ring 31 elastically abuts against the rotor shaft 2, and the radial inner end of the one-way outer sealing ring 32 elastically abuts against the rotor shaft 2 to ensure that the one-way inner sealing ring 31 and the one-way outer sealing ring 32 achieve a good seal with the rotor shaft 2 through elastic abutment. This design prevents process gases or particles from entering the suction end bearing or suction end lubrication chamber 11 through the one-way inner seal ring 31, thus preventing wear on the suction end bearing or contamination of the suction end lubrication chamber 11. The one-way outer seal ring 32 also blocks lubricating oil in the suction end lubrication chamber 11 from entering the rotor chamber 12, preventing contamination of the rotor. In this way, the entire suction end sealing assembly 3 ensures the normal operation of the entire vacuum pump.

[0039] In some embodiments, please refer to Figure 1 The pump body 1 includes a pump casing, a rotor cavity 12 and a suction end lubrication cavity 11, both of which are located inside the pump casing. The vacuum pump also includes a suction end mounting seat 14 located inside the pump casing. The suction end mounting seat 14 has an annular structure and is fixedly connected to the pump casing. The suction end mounting seat 14 is located between the rotor cavity 12 and the suction end lubrication cavity 11 in the axial direction of the rotor shaft 2.

[0040] In some embodiments, the intake end mounting seat 14 can be used as part of the intake end sealing assembly 3. The radially outer ends of the one-way inner sealing ring 31 and the one-way outer sealing ring 32 are respectively sealed with the intake end mounting seat 14. The stepped structure on the intake end mounting seat 14 can also cooperate with the retaining ring structure installed on the intake end mounting seat 14 to limit the position of the one-way inner sealing ring 31 and the one-way outer sealing ring 32 in the axial direction of the rotor shaft 2. This fixes the position of the one-way inner sealing ring 31 and the one-way outer sealing ring 32 in the axial direction of the rotor shaft 2. In this way, the intake end mounting seat 14, the one-way inner sealing ring 31 and the one-way outer sealing ring 32 form an intermediate cavity 34.

[0041] In other embodiments, please refer to Figure 1 and Figure 2 The suction end mounting seat 14 can be used as part of the pump body 1. The suction end sealing assembly 3 also includes a connecting ring 33, which is also made of rubber material. The connecting ring 33 is located on the radial outer side of the one-way inner sealing ring 31 and the one-way outer sealing ring 32, and the connecting ring 33 is connected to the radial outer end of the one-way inner sealing ring 31 and the radial outer end of the one-way outer sealing ring 32. The connecting ring 33 is sealed and fitted with the suction end mounting seat 14. The connecting ring 33, the one-way inner sealing ring 31, the one-way outer sealing ring 32 and the rotor shaft 2 enclose and form an intermediate cavity 34.

[0042] For the connecting ring 33, in one embodiment, please refer to... Figure 2 The connecting ring 33 may include a first ring body and a second ring body arranged axially on the rotor shaft 2. The first ring body is connected to the radial outer end of the one-way inner sealing ring 31, and the second ring body is connected to the radial outer end of the one-way outer sealing ring 32. The two ring bodies seal against each other axially on the rotor shaft 2.

[0043] In another embodiment, please refer to Figure 2 The connecting ring 33 can also be integrally formed, and the connecting ring 33 is connected to the radial outer end of the one-way inner sealing ring 31 and the radial outer end of the one-way outer sealing ring 32 respectively.

[0044] In one embodiment, please refer to Figure 1The rotor shaft 2 is provided with a shaft head pressure regulating air passage 21. The shaft head pressure regulating air passage 21 includes a first pressure regulating air passage 211 extending radially on the rotor shaft 2, and a second pressure regulating air passage 212 extending axially on the rotor shaft 2. The first pressure regulating air passage 211 is connected to the intermediate cavity 34 in the axial direction of the rotor shaft 2. One end of the second pressure regulating air passage 212 is connected to the first pressure regulating air passage 211, and the other end is connected to the suction end lubrication cavity 11, so that the intermediate cavity 34 and the suction end lubrication cavity 11 are connected through the shaft head pressure regulating air passage 21. This can ensure the pressure balance between the intermediate cavity 34 and the suction end lubrication cavity 11, and can avoid the generation of pressure difference on both sides of the one-way external sealing ring 32. While achieving axial sealing on both sides of the one-way external sealing ring 32 to prevent the lubricating oil in the suction end lubrication cavity 11 from entering the intermediate cavity 34 from the one-way external sealing ring 32, it can also reduce the wear between the one-way external sealing ring 32 and the rotor shaft 2.

[0045] In some embodiments, the pump body 1 is provided with an intake end pressure regulating air passage 141 for external gas, and the pump housing has an opening; in embodiments where the intake end mounting seat 14 is part of the intake end sealing assembly 3, the opening on the pump housing surrounds to form the intake end pressure regulating air passage 141, and the intake end mounting seat 14 has a through hole that penetrates in its radial direction, and the through hole corresponds to and communicates with the intake end pressure regulating air passage 141 and the intermediate cavity 34 in the axial direction of the rotor shaft 2, so that the intake end pressure regulating air passage 141 communicates with the intermediate cavity 34.

[0046] In an embodiment where the suction end mounting base 14 is part of the pump body 1, please refer to... Figure 1 and Figure 2 The through hole on the suction end mounting base 14 corresponds to the opening on the pump housing to form a suction end pressure regulating air passage 141 on the pump body 1. The connecting ring 33 is provided with a through hole that penetrates in its radial direction. This through hole forms an intermediate channel 331 on the connecting ring 33 that communicates with the intermediate cavity 34. Alternatively, two adjacent rings in the connecting ring 33 are spaced apart to form an intermediate channel 331 that communicates with the intermediate cavity 34. The suction end pressure regulating air passage 141 communicates with the intermediate channel 331 in the axial direction of the rotor shaft 2. In this way, the suction end pressure regulating air passage 141 can communicate with the intermediate cavity 34 through the intermediate channel 331.

[0047] Please refer to Figure 3 The vacuum pump sealing system also includes a gas source component, a gas pressure detection device 8, and a control device 9. The gas source component has a gas channel for supplying gas to the outside. The gas channel of the gas source component is connected to the pressure regulating gas channel 141 at the suction end to facilitate the supply of gas to the intermediate cavity 34 through the gas source component. The gas flow rate output by the gas source component is adjustable, so different flow rates of gas can be input into the intermediate cavity 34 through the gas source component.

[0048] In some embodiments, the air source assembly includes an air pump, the air passage of the air pump exhaust port is connected to the pump housing opening on the pump body 1 so that the air pump is connected to the intermediate cavity 34. The size of the air pump exhaust port is adjustable, that is, the airflow output size of the air pump is adjustable. The air pump is electrically connected to the control device 9, and the size of the air pump exhaust port can be controlled by the control device 9 to adjust the size of the air pump output airflow.

[0049] In other embodiments, the gas source assembly includes a gas source 6 and a gas valve 7. The gas source 6 can be a gas storage tank or external air from the vacuum pump. When the gas source 6 is external air from the vacuum pump, it satisfies the requirement that the rotor chamber 12 in the vacuum pump can vary between vacuum and atmospheric pressure. When the gas source 6 is a gas storage tank, the gas storage tank can provide an airflow with a pressure higher than atmospheric pressure, satisfying the requirement that the rotor chamber 12 in the vacuum pump has a pressure higher than atmospheric pressure. The gas source 6 is connected to the gas valve 7, which can be a throttle valve. The outlet of the gas valve 7 is connected to the opening of the pump casing through a gas passage, and the airflow output in the gas passage can be adjusted by the gas valve 7.

[0050] The rotor cavity 12 has an intake port 121 and an exhaust port 122 located axially at both ends of the rotor shaft 2. The intake port 121 and the intake end are located on the same side of the rotor cavity 12, and the exhaust port 122 and the exhaust end are located on the same side of the rotor cavity 12. The exhaust port 122 is directly connected to the external space of the vacuum pump, and the air pressure of the exhaust port 122 is atmospheric pressure. The intake port 121 is connected to external equipment. The intake end sealing assembly 3 is located between the intake port 121 of the rotor cavity 12 and the intake end lubrication cavity 11.

[0051] In one embodiment, the air pressure detection device 8 can be installed on the pump body 1, and the detection end of the air pressure detection device 8 is located at the air intake 121 of the rotor cavity 12 to detect the air pressure at the air intake 121 of the rotor cavity 12.

[0052] In another embodiment, the air pressure detection device 8 can be installed outside the pump body 1. The air pressure detection device 8 can be connected to the air intake 121 of the rotor cavity 12 through an air pipe to detect the air pressure in the air intake 121 of the rotor cavity 12.

[0053] The control device 9 is electrically connected to the air pressure detection device 8 and the air source component, such as to the air pump or the air valve 7. The control device 9 can control the airflow output of the air source component according to the detection result of the air pressure detection device 8.

[0054] In this way, during the process of air pressure change at the air intake port 121 of the rotor cavity 12, the air pressure at the air intake port 121 of the rotor cavity 12 can be detected in real time by the air pressure detection device 8, and the control device 9 can control the airflow output of the air source component in real time according to the air pressure change at the air intake port 121 of the rotor cavity 12 detected by the air pressure detection device 8. For example, during the process of changing from vacuum to high pressure at the air intake port 121 of the rotor cavity 12, the opening size of the air valve 7 can be gradually increased as the air pressure at the air intake port 121 of the rotor cavity 12 gradually increases, thereby gradually increasing the air pressure in the intermediate cavity 34. Alternatively, during the process of changing from high pressure to vacuum at the air intake port 121 of the rotor cavity 12, the opening size of the air valve 7 can be gradually decreased as the air pressure at the air intake port 121 of the rotor cavity 12 gradually decreases. As the one-way inner sealing ring 31 opens, the air pressure in the intermediate cavity 34 can be gradually reduced to decrease the pressure difference on both sides of the one-way inner sealing ring 31, thereby balancing the pressure difference on both sides of the one-way inner sealing ring 31. This ensures a good seal for the one-way inner sealing ring 31 while effectively reducing wear between the one-way inner sealing ring 31 and the rotor shaft 2, and extending the service life of the one-way inner sealing ring 31.

[0055] In one embodiment, the vacuum pump sealing system includes a pressure sensor connected in series on the air pipe between the air source assembly and the intermediate cavity 34. The pressure sensor is connected to the control device 9 to detect the air pressure of the intermediate cavity 34 in real time. When the control device 9 controls the airflow output of the air source assembly, it also monitors the air pressure of the intermediate cavity 34 and the air pressure of the air intake 121 of the rotor cavity 12 in real time to ensure that the air pressure of the intermediate cavity 34 is slightly greater than the air pressure of the air intake 121 of the rotor cavity 12, but less than the sum of the air pressure of the air intake 121 of the rotor cavity 12 and the sealing pressure of the one-way inner sealing ring 31, so that the wear of the one-way inner sealing ring 31 is minimized.

[0056] In one embodiment, please refer to Figure 1 The structure of the exhaust end sealing assembly 5 can be the same as that of the intake end sealing assembly 3. The exhaust end sealing assembly 5 has an intermediate sealing cavity (not shown in the figure) corresponding to the intermediate cavity 34 in the intake end sealing assembly 3. The pump body 1 is provided with an exhaust end pressure regulating air passage (not shown in the figure). The exhaust end pressure regulating air passage is connected to the intermediate sealing cavity. The structure of the exhaust end pressure regulating air passage and the connection between the exhaust end pressure regulating air passage and the intermediate sealing cavity is the same as the structure of the intake end pressure regulating air passage 141 and the connection between the intake end pressure regulating air passage 141 and the intermediate cavity 34. It will not be described again here.

[0057] The gas source 6 in the gas source assembly is also connected to the pressure regulating gas channel at the exhaust end through a gas pipe. In this way, gas can be supplied to the intermediate sealing cavity of the exhaust end sealing assembly 5 through the gas source 6. Since the gas pressure of the exhaust port 122 in the exhaust end lubrication cavity 13 and the rotor cavity 12 is roughly the same, and the exhaust port 122 is connected to atmospheric pressure, it is necessary to supply high-pressure gas with a pressure greater than atmospheric pressure into the intermediate sealing cavity in order to form a high-pressure cavity sealing structure between the exhaust end lubrication cavity 13 and the rotor cavity 12. This helps to improve the sealing performance of the exhaust end of the vacuum pump.

[0058] This application also provides a control method for the vacuum pump sealing system in any of the above embodiments, the method comprising:

[0059] When the air pressure detection device 8 detects an increase in air pressure at the air inlet 121, the control device 9 controls the air source assembly to increase the airflow output;

[0060] When the air pressure detection device 8 detects a decrease in air pressure at the air inlet 121, the control device 9 controls the air source component to reduce or stop the airflow output.

[0061] The gas supply flow rate of the gas source component is mainly controlled in real time according to the operating conditions of the vacuum pump. In one embodiment, in the initial state of the vacuum pump, the air intake 121 of the rotor cavity 12 is at normal pressure, and the intermediate cavity 34 is also at normal pressure. During the process of the air intake 121 of the rotor cavity 12 changing from normal pressure to low pressure, the air pressure detection device 8 can convert the real-time air pressure value of the air intake 121 of the rotor cavity 12 into an air pressure signal of the air intake 121 of the rotor cavity 12 and transmit it to the control device 9. The control device 9 can control the opening of the air pump exhaust port or the air valve 7 in the gas source component to gradually decrease according to the decrease of the air pressure of the air intake 121 of the rotor cavity 12, so as to reduce the air pressure difference between the intermediate cavity 34 and the air intake 121 of the rotor cavity 12, reduce the opening size of the one-way inner sealing ring 31, or even prevent the one-way inner sealing ring 31 from opening, reduce the pressure difference on both sides of the one-way inner sealing ring 31, thereby reducing the wear of the one-way inner sealing ring 31.

[0062] Furthermore, in one embodiment, when the air pressure at the intake port 121 of the rotor cavity 12 decreases, the control device 9 controls the air pump exhaust port or the opening of the air valve 7 in the air source assembly to gradually decrease until the air pressure at the intake port 121 of the rotor cavity 12 decreases to a limit value and no longer decreases, then controls the air pump exhaust port or the opening of the air valve 7 in the air source assembly to close to stop supplying air to the intermediate cavity 34.

[0063] In another embodiment, the control device 9 can also directly close the exhaust port of the air pump or the opening of the air valve 7 in the air source assembly according to the decrease of the air pressure at the air intake port 121 of the rotor cavity 12. In this way, as the air pressure at the air intake port 121 gradually decreases, the one-way inner sealing ring 31 opens, and the air pressure in the intermediate cavity 34 also decreases accordingly, until the air pressure at the air intake port 121 and the air pressure in the intermediate cavity 34 are approximately equal. The inner end of the one-way inner sealing ring 31 elastically abuts against the rotor shaft 2, and the pressure difference on both sides of the one-way inner sealing ring 31 is small, which can achieve the purpose of reducing the wear of the one-way inner sealing ring 31.

[0064] In one embodiment, when the suction port 121 of the rotor chamber 12 of the vacuum pump is in a low-pressure state, the air pressure in the intermediate cavity 34 is similar to or equal to the air pressure in the suction port 121 of the rotor chamber 12. During the process of the air pressure in the suction port 121 of the rotor chamber 12 changing from low pressure to high pressure, the air pressure detection device 8 can convert the real-time air pressure value of the suction port 121 of the rotor chamber 12 into an air pressure signal of the suction port 121 of the rotor chamber 12 and transmit it to the control device 9. The control device 9 can control the air pump exhaust port or the opening of the air valve 7 in the air source assembly to gradually increase according to the increase of the air pressure in the suction port 121 of the rotor chamber 12, so as to reduce the air pressure difference between the air pressure in the intermediate cavity 34 and the air pressure in the suction port 121 of the rotor chamber 12, thereby achieving the purpose of reducing the wear of the one-way inner sealing ring 31.

[0065] In summary, the control method of the vacuum pump sealing system of this application mainly controls the airflow output of the air source component in real time based on the air pressure change of the suction port 121 of the rotor cavity 12, so as to reduce the pressure difference between the intermediate cavity 34 and the suction port 121 of the rotor cavity 12, reduce the pressure difference between the inside and outside of the one-way inner sealing ring 31, and reduce the wear of the one-way inner sealing ring 31. Of course, since the rotor shaft 2 has a shaft head pressure regulating air passage 21 connecting the intermediate cavity 34 and the suction end lubrication cavity 11, the intermediate cavity 34 is always connected to the suction end lubrication cavity 11 through the shaft head pressure regulating air passage 21. When the air pressure in the intermediate cavity 34 changes, the air pressure in the suction end lubrication cavity 11 also changes accordingly. This can also reduce the pressure difference on both sides of the one-way outer sealing ring 32, thereby reducing the wear of the one-way outer sealing ring 32.

[0066] Furthermore, in one embodiment, a pressure sensor can be connected in series on the air pipe between the air source assembly and the intermediate cavity 34, and the pressure sensor can be connected to the control device 9. The control device 9 can then detect the air pressure in the intermediate cavity 34 in real time. Throughout the process of controlling the change in the airflow output of the air source assembly, the control device 9 can control the rate of change of the airflow output of the air source assembly based on the comparison between the air pressure in the intermediate cavity 34 and the air pressure at the intake port 121 of the rotor cavity 12, so as to maintain the air pressure in the intermediate cavity 34 always greater than that at the intake port 121 of the rotor cavity 12. The air pressure is 1, and less than the sum of the air pressure at the air intake 121 of the rotor cavity 12 and the sealing air pressure of the one-way inner sealing ring 31. This avoids the air source component's output flow increasing too slowly during the process of increasing the output flow, or the air source component's output flow decreasing too quickly during the process of decreasing the output flow, which would cause the air pressure in the intermediate cavity 34 to be less than the air pressure at the air intake 121 of the rotor cavity 12. This can more effectively reduce the wear of the one-way inner sealing ring 31 and increase the impact of the air source component's output flow regulation on reducing the wear of the one-way inner sealing ring 31.

[0067] In an embodiment where the gas source 6 of the vacuum pump sealing system is connected to the intermediate sealing cavity of the vacuum pump exhaust end sealing assembly 5, the control method of the vacuum pump sealing system further includes supplying gas to the intermediate sealing cavity through the gas source 6. The gas source 6 can be a high-pressure gas source higher than atmospheric pressure, such as a gas storage tank. By supplying high-pressure gas to the intermediate sealing cavity through the gas source 6, the gas pressure in the intermediate sealing cavity is made higher than the gas pressure in the exhaust end lubrication cavity 13 and also higher than the gas pressure in the exhaust port 122, thereby achieving a better seal at the exhaust end of the vacuum pump. Of course, in other embodiments, if the sealing effect at the exhaust end of the vacuum pump is good, it may not be necessary to supply gas to the intermediate sealing cavity of the exhaust end sealing assembly 5.

[0068] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A vacuum pump sealing system, characterized in that, Includes vacuum pumps, gas source components, gas pressure detection devices, and control devices; The vacuum pump includes a pump body, a rotor shaft, and an intake end sealing assembly. The pump body has a rotor cavity and an intake end lubrication cavity. The rotor cavity has an intake port and an exhaust port. The rotor shaft is rotatably mounted in the pump body. The intake end sealing assembly is sealed between the pump body and the rotor shaft to separate the rotor cavity and the intake end lubrication cavity. The suction end sealing assembly includes a one-way inner sealing ring and a one-way outer sealing ring. The suction end sealing assembly and the rotor shaft enclose an intermediate cavity between the one-way inner sealing ring and the one-way outer sealing ring. The pump body has a suction end pressure regulating air passage, which connects the intermediate cavity with the air passage of the air source assembly. The rotor shaft has a shaft head pressure regulating air passage, which connects the intermediate cavity with the suction end lubrication cavity. The air pressure detection device is used to detect the air pressure at the air inlet. The control device is electrically connected to both the air pressure detection device and the air source assembly. The control device can control the airflow output of the air source assembly based on the detection result of the air pressure detection device to reduce the air pressure difference between the air inlet and the intermediate cavity. When controlling the airflow output of the air source assembly, the control device controls the air pressure in the intermediate cavity to be greater than the air pressure at the air inlet and less than the sum of the air pressure at the air inlet and the sealing pressure of the one-way inner sealing ring.

2. The vacuum pump sealing system as described in claim 1, characterized in that, Along the axial direction of the rotor shaft, the one-way inner sealing ring is located between the rotor cavity and the one-way outer sealing ring, and the one-way inner sealing ring is used to achieve a seal from the rotor cavity to the suction end lubrication cavity; the one-way outer sealing ring is located between the one-way inner sealing ring and the suction end lubrication cavity, and the one-way outer sealing ring is used to achieve a seal from the suction end lubrication cavity to the rotor cavity; both the one-way inner sealing ring and the one-way outer sealing ring seal the rotor shaft.

3. The vacuum pump sealing system as described in claim 2, characterized in that, The intake end sealing assembly further includes a connecting ring, which is located radially outside the one-way inner sealing ring and the one-way outer sealing ring. The connecting ring, the one-way inner sealing ring, the one-way outer sealing ring and the rotor shaft enclose the intermediate cavity. The connecting ring has an intermediate channel connecting the intermediate cavity and the intake end pressure regulating air passage. The connecting ring includes a first ring body and a second ring body arranged axially on the rotor shaft at intervals. The one-way inner sealing ring is connected to the first ring body, and the one-way outer sealing ring is connected to the second ring body. The intermediate channel is located between the first ring body and the second ring body; or, the connecting ring, the one-way inner sealing ring, and the one-way outer sealing ring are integrally formed.

4. The vacuum pump sealing system as described in claim 1, characterized in that, The air pressure detection device is installed on the pump body and is located at the air inlet.

5. The vacuum pump sealing system as described in claim 1, characterized in that, The air source assembly includes an air source and an air valve, the air valve being electrically connected to the control device; the air passage of the air source is connected to the intermediate cavity through the pressure regulating air passage at the intake end, and the air valve is used to control the airflow output of the air source; Alternatively, the air source assembly includes an air source with an adjustable airflow output, the air source being electrically connected to the control device, and the control device being able to control the airflow output of the air source.

6. The vacuum pump sealing system as described in claim 5, characterized in that, The pump body also has an exhaust end lubrication chamber. The vacuum pump includes an exhaust end sealing assembly, which seals the pump body and the rotor shaft respectively to separate the rotor cavity from the exhaust end lubrication chamber. The exhaust end sealing assembly and the rotor shaft enclose an intermediate sealing cavity. The gas source's gas passage is also connected to the intermediate sealing cavity for supplying gas to the intermediate sealing cavity.

7. The vacuum pump sealing system as described in claim 1, characterized in that, The vacuum pump sealing system includes a pressure sensor, which is electrically connected to the control device and is used to detect the pressure in the intermediate cavity.

8. A control method for a vacuum pump sealing system as described in any one of claims 1 to 5, characterized in that, include: When the air pressure detection device detects an increase in air pressure at the air inlet, the control device controls the air source assembly to increase the airflow output; When the air pressure detection device detects a decrease in air pressure at the air inlet, the control device controls the air source component to reduce or stop the airflow output.

9. The control method for the vacuum pump sealing system as described in claim 8, characterized in that, When the air pressure detection device detects that the air pressure at the air inlet has decreased to a limit value, the control device controls the air source component to stop airflow output.

10. The control method for the vacuum pump sealing system as described in claim 8, characterized in that, The vacuum pump sealing system includes a pressure sensor, which is electrically connected to the control device and is used to detect the pressure in the intermediate cavity. The control method of the vacuum pump sealing system further includes: when the control device controls the airflow output of the gas source component, it controls the air pressure of the intermediate cavity to be greater than the air pressure of the air inlet and less than the sum of the air pressure of the air inlet and the sealing pressure of the one-way inner sealing ring.

11. The control method for the vacuum pump sealing system as described in claim 8, characterized in that, The pump body also has an exhaust end lubrication chamber, and the vacuum pump includes an exhaust end sealing assembly. The exhaust end sealing assembly seals the pump body and the rotor shaft respectively to separate the rotor cavity from the exhaust end lubrication chamber. The exhaust end sealing assembly and the rotor shaft enclose an intermediate sealing cavity. The gas source assembly includes a gas source, and the gas source's air passage is also connected to the intermediate sealed cavity; The control method for the vacuum pump sealing system also includes: The gas source supplies gas to the intermediate sealing cavity, controlling the gas pressure in the intermediate sealing cavity to be higher than the gas pressure in the exhaust end lubrication cavity, and also higher than the gas pressure at the exhaust port.

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