Molecular pump anti-impact device and molecular pump
Through the unidirectional transmission design of the mechanical structure, the turbine rotor avoids obstacles when rotating in the forward direction and blocks them when rotating in the reverse direction, forming a physical barrier. This solves the problem of backflow airflow impact in molecular pumps and improves the safety and reliability of the system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-03-27
AI Technical Summary
In existing technologies, molecular pumps experience delays in electronic control response when subjected to backflow gas impacts, which may prevent timely intervention to stop the impact on the rotor, leading to the risk of rotor breakage and equipment damage.
The mechanical structure employs a unidirectional transmission design, including a turbine rotor and a unidirectional transmission structure. The turbine rotor avoids the airflow when rotating in the forward direction and blocks it when rotating in the reverse direction, forming a physical barrier that limits the rate and volume of reverse airflow and slows down the pressure rise.
It achieves instantaneous response without electrical control triggering, protects the molecular pump rotor and equipment safety, improves the operational reliability and safety of the vacuum system, and avoids equipment damage and personnel injury.
Smart Images
Figure CN121738951A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of molecular pump technology, specifically to a molecular pump shock-resistant device and a molecular pump. Background Technology
[0002] Molecular pumps are core equipment in modern high-vacuum and ultra-high-vacuum systems for achieving a clean vacuum environment. Their working principle involves using high-speed rotating blades to directionally drag gas molecules, thereby achieving the purpose of pumping gas.
[0003] When a molecular pump is operating normally, if the upstream pipeline suddenly experiences a large-scale gas leak or is directly exposed to the atmosphere due to external force damage, valve misoperation, bellows rupture, or mechanical pump failure, a large amount of gas will instantly rush back into the molecular pump chamber. The high-speed reverse-flowing airflow will drastically increase the load on the molecular pump rotor, generating huge resistance torque and heat, which can easily cause the rotor to break and shatter due to excessive stress, forming high-speed splashing metal fragments.
[0004] Existing technologies often employ pressure sensors and electrical control systems that rely on vacuum gauges. When an abnormal increase in the forestage pressure is detected, the system issues an alarm and urgently stops the molecular pump. However, there is an unavoidable delay in the electrical control response. Therefore, there is an urgent need for a physical barrier device based on a purely mechanical structure that can respond instantaneously, to buy time for the electrical control system to react and thus prevent catastrophic accidents. Summary of the Invention
[0005] This invention provides a molecular pump anti-impact device and a molecular pump to solve the problem in the prior art that the reliance on electronic control response has a time delay, which leads to the inability to stop the backflow of airflow from impacting the molecular pump rotor in time.
[0006] In a first aspect, the present invention provides a molecular pump shock-resistant device, comprising: Pipe casing; The hub is located inside the pipe casing; The turbine rotor is rotatably mounted on a hub; the turbine rotor includes a shaft and multiple sets of turbine blades, which are spaced apart along the axial direction of the shaft. The unidirectional transmission structure is configured corresponding to the turbine rotor. The unidirectional transmission structure has an avoidance state and a blocking state. When the turbine rotor rotates in the forward direction, the unidirectional transmission structure is in the avoidance state to allow the turbine rotor to rotate normally; when the turbine rotor rotates in the reverse direction, the unidirectional transmission structure switches to the blocking state to prevent the turbine rotor from rotating.
[0007] Beneficial effects: Through the unidirectional transmission design of the mechanical structure, instantaneous response can be achieved without electronic triggering. During normal pumping, the resistance to airflow is minimal, without affecting the system's pumping performance. When a reverse pressure impact occurs in the pre-stage system connected to the molecular pump's shock-resistant device, the unidirectional transmission structure can lock instantly and automatically. Multiple turbine blades form a physical barrier, limiting the rate and volume of the reverse impact airflow. By slowing the pressure rise, time is provided for the control system to make judgments and respond, preventing the molecular pump rotor from receiving a devastating impact in a short period. This improves the operational reliability and safety of the molecular pump and the entire vacuum system, protecting equipment and personnel safety.
[0008] In one optional embodiment, the pipe casing has an air inlet and an air outlet, and the direction from the air inlet to the air outlet is defined as the first direction; Along the first direction, multiple sets of turbine blades are arranged in sequence, the angle of attack of the multiple sets of turbine blades decreases in sequence, and the number of blades in each set of turbine blades increases in sequence.
[0009] Beneficial effects: The blades at the end closest to the molecular pump have the largest angle of attack. When the backflow reaches the inlet of the molecular pump, the blades with the largest angle of attack can convert the impact force of the airflow into a huge reverse torque and axial force to the maximum extent. The blades at the end closest to the fore-stage system have the smallest angle of attack, which reduces the resistance to the airflow and can maximize the pumping speed of the system.
[0010] In one alternative implementation, the blades and blade gaps of two adjacent sets of turbine blades overlap each other in the axial projection.
[0011] Beneficial effects: From the axial perspective of the turbine rotor, the blade region forms a nearly sealed barrier with no direct passage. This prevents airflow from passing directly through and forces it to traverse a tortuous path between the blades, increasing the flow resistance of the reverse airflow and preventing the formation of instantaneous pressure shocks from the reverse airflow.
[0012] In one alternative implementation, the unidirectional transmission structure includes: A ratchet, which is mounted on a rotating shaft; The pawl is mounted on the hub, and the ratchet and pawl are engaged.
[0013] In one alternative embodiment, the hub at one end of the pipe housing is detachably connected to the pipe housing; or the hubs at both ends of the pipe housing are detachably connected to the pipe housing; or the hubs at both ends of the pipe housing are fixedly connected to the pipe housing.
[0014] Beneficial effects: One or both hubs can be detachably connected, eliminating the need to completely disassemble the pipe casing, reducing the use of tools and assembly steps, shortening operation time, and facilitating subsequent maintenance; fixed connection at both ends allows the molecular pump impact-resistant device to be installed in place in one go, avoiding misalignment and loosening after installation, and reducing the probability of backlash; three connection methods can be selected as needed, reducing labor and time costs.
[0015] In one alternative implementation, the turbine blades are provided in four sets.
[0016] In one optional embodiment, the device further includes a bearing mounted on a hub via a bearing housing. The hub has a stepped structure with a first stepped section and a second stepped section sequentially arranged along the hub axial direction. The device also includes a pressure relief device disposed between the hub and the turbine rotor. The pressure relief device includes at least one first elastic element, one end of which abuts against the bearing housing and the other end of which abuts against the first stepped section. The first elastic element is used to buffer axial vibration between the shaft and the hub.
[0017] Beneficial effects: When the turbine rotor is locked, the huge reverse pressure difference acts on the turbine blades, forming a huge axial force. When the axial force exceeds the preload of the first elastic element, the turbine rotor will produce a slight axial movement. The greater the pressure difference, the greater the axial force, and the spring compression is also appropriately increased, thereby achieving stable axial pressure relief, improving the safety of the device operation, extending the service life of core components, and enhancing the overall reliability of the system. In one alternative embodiment, the pressure relief device further includes at least one second elastic element, one end of which abuts against the bearing housing and the other end of which abuts against the second stepped section. The second elastic element is used to buffer radial vibration between the shaft and the hub.
[0018] Beneficial effects: The second elastic element can buffer the radial vibration and offset between the shaft and the hub, improve the overall vibration resistance of the device, avoid structural loosening or increased sealing gap caused by radial vibration, and ensure the smooth operation of the molecular pump under complex working conditions.
[0019] In one alternative embodiment, the pipe housing includes a connector for connecting the molecular pump shock absorber and the molecular pump.
[0020] Secondly, the present invention also provides a molecular pump, comprising: Pump body, including a gas inlet end and a gas outlet end; And a molecular pump shock resistant device, which can be detachably installed at the gas outlet end of the pump body.
[0021] Beneficial effects: The molecular pump anti-impact device can form a protective barrier at the pump outlet to avoid the instantaneous pressure difference impact of the backflow airflow. It effectively prevents the backflow airflow from causing the pump rotor to reverse and generate violent vibration, and avoids safety hazards such as pump casing damage or bolt breakage caused by the high-speed rotating pump rotor releasing a large amount of kinetic energy due to airflow impact. Attached Figure Description
[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0023] Figure 1 This is a schematic diagram of a molecular pump shock-resistant device and a molecular pump according to an embodiment of the present invention; Figure 2 for Figure 1 Enlarged schematic diagram of the structure at point A in the middle; Figure 3 for Figure 1 A schematic diagram of the turbine rotor.
[0024] Explanation of reference numerals in the attached figures: 1. Pipe casing; 11. Connecting part; 2. Hub; 21. First step; 22. Second step; 3. Turbine rotor; 31. Shaft; 32. Turbine blade; 4. Ratchet; 5. Pawl; 6. Pressure relief device; 61. First elastic element; 62. Second elastic element; 7. Bearing; 8. Bearing housing; 9. Support; 10. Locking element. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] Molecular pumps are core equipment in modern high-vacuum and ultra-high-vacuum systems for achieving a clean vacuum environment. Their working principle involves using high-speed rotating blades to directionally drag gas molecules, thereby achieving the purpose of pumping gas.
[0027] When a molecular pump is operating normally, if a large-scale gas leak suddenly occurs in the upstream pipeline due to external force damage, valve misoperation, bellows rupture, or mechanical pump failure, or if it is directly exposed to the atmosphere, a large amount of gas will instantly backflow into the molecular pump chamber. This high-speed, reverse-flowing gas will drastically increase the load on the molecular pump rotor, generating enormous resistance torque and heat. This can easily lead to rotor overload stall or breakage, causing the rotor to fracture and shatter due to excessive stress, forming high-speed spinning metal fragments. These high-speed flying metal fragments threaten equipment and personal safety; they may puncture the molecular pump body and pose an extremely serious threat to the personal safety of on-site personnel. Simultaneously, they can contaminate the vacuum system, requiring shutdown for cleaning and resulting in significant losses.
[0028] Existing technologies often employ pressure sensors and electrical control systems that rely on vacuum gauges. When an abnormal increase in the upstream pressure is detected, the system issues an alarm and urgently stops the molecular pump. However, there is an unavoidable delay in the electrical control response; from detection and judgment to execution of shutdown, it takes hundreds of milliseconds or even longer. But physical airflow impacts can occur within milliseconds. Therefore, there is an urgent need for a physical barrier device based on a purely mechanical structure that can respond instantaneously, to buy time for the electrical control system to react and thus prevent serious accidents from occurring.
[0029] The following is combined Figures 1 to 3 The following describes embodiments of the present invention.
[0030] According to an embodiment of the present invention, in one aspect, a molecular pump shock-resistant device is provided, comprising: Pipe casing 1; Hub 2, hub 2 is installed inside pipe housing 1; The turbine rotor 3 is rotatably mounted on the hub 2. The turbine rotor 3 includes a rotating shaft 31 and multiple sets of turbine blades 32, which are spaced apart along the axial direction of the rotating shaft 31. A one-way transmission structure is provided corresponding to the turbine rotor 3. The one-way transmission structure has an avoidance state and a blocking state. When the turbine rotor 3 rotates in the forward direction, the one-way transmission structure is in the avoidance state so that the turbine rotor 3 can rotate normally. When the turbine rotor 3 rotates in the reverse direction, the one-way transmission structure switches to the blocking state to prevent the turbine rotor 3 from rotating.
[0031] Through the unidirectional transmission design of the mechanical structure, instantaneous response can be achieved without electronic control triggering. When the molecular pump is pumping gas normally, the resistance to airflow is minimal, and it does not affect the pumping performance of the system. When a reverse pressure shock occurs in the backstage system connected to the molecular pump shock absorber, the airflow generates a reverse driving torque on the turbine blades 32. Driven by the reverse airflow, the turbine rotor 3 reverses direction. The unidirectional transmission structure immediately locks the turbine rotor 3 in place, and multiple sets of turbine blades 32 form a physical barrier, limiting the rate and total volume of the reverse impact airflow. By slowing the pressure rise, the control system has time to make a judgment and respond, preventing the molecular pump rotor from experiencing a large impact in a short period. This improves the operational reliability and safety of the molecular pump and the entire vacuum system, protecting equipment and personnel safety.
[0032] In one embodiment, the pipe housing 1 is provided with an air inlet and an air outlet, and the direction from the air inlet toward the air outlet is defined as the first direction; Along the first direction, multiple sets of turbine blades 32 are arranged in sequence, the angle of attack of the multiple sets of turbine blades 32 decreases in sequence, and the number of blades in each set of turbine blades 32 increases in sequence.
[0033] The turbine blade 32 closest to the molecular pump has the largest angle of attack. When the backflow reaches the inlet of the molecular pump, the turbine blade 32 with the largest angle of attack can convert the impact force of the airflow into a huge reverse torque and axial force to the maximum extent. The turbine blade 32 closest to the fore-stage system has the smallest angle of attack, which has less resistance to the airflow and can ensure the pumping speed of the system to the maximum extent.
[0034] In one embodiment, the blades and blade gaps of two adjacent sets of turbine blades 32 overlap each other in axial projection.
[0035] From the axial perspective of the turbine rotor 3, the blade region forms a nearly sealed barrier with no direct passage. This prevents airflow from passing directly through and forces it to traverse a tortuous path between the blades, increasing the flow resistance of the reverse airflow and preventing the formation of instantaneous pressure shocks from the reverse airflow.
[0036] In one embodiment, the unidirectional transmission structure includes: Ratchet 4 is mounted on shaft 31; Pad 5 is mounted on hub 2, and ratchet 4 and pad 5 are engaged.
[0037] Pawls 5 are provided on the hubs 2 at one or both ends of the pipe housing, and ratchet 4 is correspondingly set on the rotating shaft 31. When a sudden air leakage occurs in the pre-stage, the airflow direction is reversed instantly, and the reverse airflow impacts the turbine blades 32 at extremely high speed, generating a torque that causes the turbine rotor 3 to rotate in the opposite direction. At this time, ratchet 4 and pawl 5 lock, preventing the rotating shaft 31 from rotating in the opposite direction.
[0038] Alternatively, the unidirectional transmission structure can also use unidirectional bearings, worm gear structures, etc.
[0039] In one embodiment, the hub 2 at one end of the pipe housing 1 is detachably connected to the pipe housing 1; or the hubs 2 at both ends of the pipe housing 1 are detachably connected to the pipe housing 1; or the hubs 2 at both ends of the pipe housing 1 are fixedly connected to the pipe housing 1.
[0040] One or both hubs 2 can be detachably connected, eliminating the need to completely disassemble the pipe shell 1, reducing the use of tools and assembly steps, shortening operation time, and facilitating subsequent maintenance. The connection method can be selected as needed, reducing labor and time costs.
[0041] Optionally, the hub 2 can be detachably fixed to the pipe shell 1 by means of flange connection, bolt connection, clamp structure, etc.
[0042] In one embodiment, the turbine blades 32 are provided in four sets.
[0043] The turbine blade 32 closest to the inlet side of the molecular pump is the first stage. The first-stage turbine blade 32 has the largest angle of attack and the longest chord length, but the number of blades is relatively small. When the reverse impact airflow reaches the first-stage turbine blade 32, its maximum angle of attack characteristic can maximize the conversion of the airflow's impact force into a huge reverse torque and axial force. The first-stage turbine blade 32 generates the largest torque force, and its large projected area also makes it the main sealing surface after locking. During normal operation, because the first-stage turbine blade 32 is located at the beginning of the flow channel, its large angle of attack has a controllable impact on the overall flow channel. The second-stage turbine blade 32 is adjacent to the first stage. Its angle of attack is smaller than that of the first-stage turbine blade 32, and the number of blades is greater than that of the first-stage turbine blade 32. The second-stage turbine blade 32 works in conjunction with the first-stage turbine blade 32 and is one of the main sources of the reverse torque required for locking, further converting the kinetic energy of the impact airflow into braking torque. The third-stage turbine blade 32 is located in the middle of the turbine rotor 3. Its angle of attack is further reduced compared to the second-stage turbine blade 32, and its blade density is increased. This allows for secondary braking of the impacting airflow penetrating the first and second stages, guiding the airflow to the high-angle-of-attack curved surfaces of the first and second-stage turbine blades 32. The fourth-stage turbine blade 32 is closest to the preceding system, with the smallest angle of attack and the largest number of blades. Its small angle of attack and high density design minimize resistance to the forward airflow, maximizing the system's pumping speed and ultimate vacuum. While the braking force of a single fourth-stage turbine blade 32 is relatively small, the accumulation of multiple blades generates significant initial drag, immediately transmitting the impact signal to the second-stage blades.
[0044] Optionally, the turbine blades 32 can also be three-stage, five-stage, etc.
[0045] In one embodiment, the device further includes a bearing 7, which is mounted on the hub 2 via a bearing seat 8. The hub 2 has a stepped structure, with a first stepped section 21 and a second stepped section 22 sequentially arranged along the axial direction of the hub 2. The device also includes a pressure relief device 6, which is disposed between the hub 2 and the turbine rotor 3. The pressure relief device 6 includes at least one first elastic element 61, one end of which abuts against the bearing seat 8 and the other end of which abuts against the first stepped section 21. The first elastic element 61 is used to buffer the axial vibration between the shaft 31 and the hub 2.
[0046] The wheel hub 2 is manufactured using a one-piece molding process. The first step 21 and the second step 22 are integral features processed by turning and other processes. The one-piece design in this embodiment can avoid vibration caused by gaps at the connection and avoid the risk of loosening at the connection.
[0047] Optionally, the first elastic element 61 can be a spring, damper, or the like.
[0048] When the turbine rotor 3 is locked, the huge reverse pressure difference acts on the turbine blades 32, forming a huge axial force. When the axial force exceeds the preload of the first elastic element 61, the turbine rotor 3 will produce a slight axial movement. The greater the pressure difference, the greater the axial force, and the spring compression is also appropriately increased, thereby achieving stable axial pressure relief, improving the safety of device operation, extending the service life of core components, and enhancing the overall reliability of the system. In one embodiment, the pressure relief device 6 further includes at least one second elastic element 62, one end of which abuts against the bearing seat 8 and the other end of which abuts against the second stepped section 22. The second elastic element 62 is used to buffer the radial vibration between the shaft 31 and the hub 2.
[0049] Optionally, the second elastic element 62 can be a damping rubber ring, rubber bushing, etc.
[0050] The second elastic element 62 can buffer the radial vibration and offset between the rotating shaft 31 and the hub 2, improve the overall vibration resistance stability of the device, avoid structural loosening or increased sealing gap caused by radial vibration, and ensure the smooth operation of the molecular pump under complex working conditions.
[0051] In one embodiment, the pipe housing 1 includes a connector 11 for connecting the molecular pump shockproof device and the molecular pump.
[0052] Optionally, the connecting part 11 can be a flange, quick-release clamp, etc.
[0053] A support member 9 is also provided between the hub 2 and the molecular pump. The support member 9 is used to fix the hub 2. In this embodiment, as shown... Figure 1 As shown, the support member 9 is set as a cylindrical shape.
[0054] Locking elements 10 are provided at both ends of the rotating shaft 31. The locking elements 10 abut against the bearings 7 at both ends of the rotating shaft 31. In this embodiment, the locking elements 10 are lock nuts.
[0055] According to an embodiment of the present invention, in another aspect, a molecular pump is also provided, comprising: Pump body, including a gas inlet end and a gas outlet end; And a molecular pump shock resistant device, which can be detachably installed at the gas outlet end of the pump body.
[0056] The molecular pump anti-impact device can form a protective barrier at the pump outlet to avoid the instantaneous pressure difference impact of the backflow airflow. It effectively prevents the backflow airflow from causing the pump rotor to reverse and generate violent vibration, and avoids safety hazards such as pump casing damage or bolt breakage caused by the high-speed rotating pump rotor releasing a large amount of kinetic energy due to airflow impact.
[0057] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A molecular pump shock-resistant device, characterized in that, include: Pipe casing (1); Hub (2), said hub (2) is disposed inside the pipe housing (1); A turbine rotor (3) is rotatably mounted on the hub (2); the turbine rotor (3) includes a shaft (31) and multiple sets of turbine blades (32), the multiple sets of turbine blades (32) being spaced apart along the axial direction of the shaft (31); A one-way transmission structure is provided corresponding to the turbine rotor (3). The one-way transmission structure has an avoidance state and a blocking state. When the turbine rotor (3) rotates in the forward direction, the one-way transmission structure is in the avoidance state so that the turbine rotor (3) can rotate normally. When the turbine rotor (3) rotates in the reverse direction, the one-way transmission structure switches to the blocking state to prevent the turbine rotor (3) from rotating.
2. The molecular pump shock-resistant device according to claim 1, characterized in that, The outer casing of the pipe (1) is provided with an air inlet and an air outlet, and the direction from the air inlet toward the air outlet is defined as the first direction; Along the first direction, multiple sets of turbine blades (32) are arranged in sequence, the angle of attack of the multiple sets of turbine blades (32) decreases in sequence, and the number of blades in each set of turbine blades (32) increases in sequence.
3. The molecular pump shock-resistant device according to claim 2, characterized in that, The blades and blade gaps of two adjacent sets of turbine blades (32) overlap each other in axial projection.
4. The molecular pump shock-resistant device according to claim 1, characterized in that, The unidirectional transmission structure includes: A ratchet (4) is mounted on the rotating shaft (31); Pawl (5), the pawl (5) is disposed on the hub (2), and the ratchet (4) and the pawl (5) are engaged.
5. The molecular pump shock-resistant device according to claim 1, characterized in that, The hub (2) at one end of the pipe shell (1) is detachably connected to the pipe shell (1); or the hubs (2) at both ends of the pipe shell (1) are detachably connected to the pipe shell (1); or the hubs (2) at both ends of the pipe shell (1) are fixedly connected to the pipe shell (1).
6. The molecular pump shock-resistant device according to claim 2, characterized in that, The turbine blades (32) are provided in four sets.
7. The molecular pump shock-resistant device according to claim 1, characterized in that, It also includes a bearing (7), which is mounted on the hub (2) via a bearing seat (8). The hub (2) has a stepped structure, with a first stepped section (21) and a second stepped section (22) arranged sequentially along the axial direction of the hub (2). It also includes a pressure relief device (6), which is disposed between the hub (2) and the turbine rotor (3). The pressure relief device (6) includes at least one first elastic element (61), one end of which abuts against the bearing seat (8) and the other end of which abuts against the first stepped section (21). The first elastic element (61) is used to buffer the axial vibration between the shaft (31) and the hub (2).
8. The molecular pump shock-resistant device according to claim 7, characterized in that, The pressure relief device (6) further includes at least one second elastic element (62), one end of which abuts against the bearing seat (8) and the other end of which abuts against the second stepped section (22). The second elastic element (62) is used to buffer the radial vibration between the shaft (31) and the hub (2).
9. The molecular pump shock-resistant device according to claim 1, characterized in that, The pipe housing (1) includes a connecting part (11) for connecting the molecular pump shockproof device and the molecular pump.
10. A molecular pump, characterized in that, include: Pump body, including a gas inlet end and a gas outlet end; And a molecular pump shock resistant device as described in any one of claims 1 to 9, wherein the molecular pump shock resistant device is detachably disposed at the gas outlet end of the pump body.