Multi-stage roots vacuum pump
By installing a pressure relief ball in the secondary compression chamber of a multi-stage Roots vacuum pump, the problem of motor overload during the start-up phase of the Roots pump is solved, thus protecting the motor and extending its service life.
Patent Information
- Application Number
- CN202511516900.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2025-11-21
AI Technical Summary
Existing Roots pumps have a defect where the motor is prone to overload during the startup phase, causing motor damage.
A multi-stage Roots vacuum pump was designed. By setting a pressure relief ball in the secondary compression chamber, when the gas pressure exceeds the set pressure, the pressure relief ball lifts the pressure relief port to release pressure, reducing excessive pressure load during secondary compression and protecting the motor.
This effectively reduces the load on the motor and extends its service life.
Smart Images
Figure CN120990887A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of vacuum pumps, specifically a multi-stage Roots vacuum pump. Background Technology
[0002] Multistage Roots dry vacuum pumps are widely used vacuum generation devices in industrial production and scientific research. They achieve direct atmospheric discharge through staged compression, reducing power consumption and lowering operating costs.
[0003] A Roots pump is a type of variable displacement vacuum pump containing two lobe-shaped rotors rotating synchronously in opposite directions. The rotors and the inner wall of the pump casing have small gaps between them, preventing direct contact. As market demands increase, the requirements for Roots pumps are also rising. However, current technology suffers from a drawback: venting only occurs in the final stage of the Roots pump, which can overload the motor and cause damage during startup.
[0004] Based on this, the present invention designs a multi-stage Roots vacuum pump to solve the above problems. Summary of the Invention
[0005] To achieve the above objectives, the present invention provides the following technical solution: a multi-stage Roots vacuum pump, comprising a pump body, a rotor disposed within the pump body, and a motor for driving the rotor to rotate, wherein the rotor comprises a male rotor and a female rotor, and the pump body is provided with a first-stage gas delivery chamber, a second-stage compression chamber, a third-stage compression chamber, a fourth-stage compression chamber, and a fifth-stage compression chamber; a first gas delivery channel is provided between the first-stage gas delivery chamber and the second-stage compression chamber; a second gas delivery channel is provided between the second-stage and third-stage compression chambers; a third gas delivery channel is provided between the third-stage and fourth-stage compression chambers; and a fourth gas delivery channel is provided between the fourth-stage and fifth-stage compression chambers. The pump body has an exhaust chamber, which is connected to the five-stage compression chamber. Rotors are installed in the first-stage, second-stage, third-stage, fourth-stage, and fifth-stage compression chambers. The pump body has a pressure relief chamber, which is connected to the second air delivery channel. The pressure relief chamber has a pressure relief port, and a pressure relief ball is placed in the pressure relief port. The pressure in the second air delivery channel is F1, and the pressure of the pressure relief ball on the pressure relief port is F2. F2 satisfies F2=m*g, where m is the weight of the pressure relief ball and g is the acceleration due to gravity. When F1>F2, the pressure relief ball opens the pressure relief port.
[0006] By adopting the above technical solution, after the gas enters the secondary compression stage, when the gas pressure exceeds the set required pressure, the pressure relief ball is lifted, thereby opening the pressure relief port and allowing the gas to be depressurized in the secondary compression chamber. This reduces the excessive load caused by excessive pressure during secondary compression, protects the motor, and improves the service life of the motor.
[0007] Preferably, the pressure relief port is configured to be larger at the top and smaller at the bottom.
[0008] By adopting the above technical solution, the design of the pressure relief port, which is larger at the top and smaller at the bottom, allows the pressure relief ball to fully return to its original position after it is lifted.
[0009] Preferably, the pressure relief ball is made of stainless steel.
[0010] By adopting the above technical solution, the corrosion of the pressure relief ball made of stainless steel can be reduced, and its service life can be improved.
[0011] Preferably, the air outlet chamber is provided with an air outlet, the air outlet has the same structure as the pressure relief port, a placement ball is placed on the air outlet, the pressure in the air outlet chamber is F3, the pressure of the placement ball on the pressure relief port is F4, and F4 satisfies F4=m*g, where m is the weight of the pressure relief ball and g is the acceleration due to gravity. When F3>F4, the placement ball opens the air outlet.
[0012] By adopting the above technical solution, after the gas pressure in the fourth-stage compression chamber reaches the required value, the ball will be placed up to exhaust the gas.
[0013] Preferably, one end of the first air supply channel is connected to the lower side of the primary air supply chamber, and the other end is connected to the upper side of the secondary compression chamber; one end of the second air supply channel is connected to the lower side of the secondary compression chamber, and the other end is connected to the upper side of the tertiary compression chamber; and so on, one end of the fourth air supply channel is connected to the lower side of the fourth compression chamber, and the other end is connected to the upper side of the fifth compression chamber.
[0014] By adopting the above technical solution, the gas is transported from top to bottom, which facilitates the layout while avoiding mutual interference between gases.
[0015] Preferably, the primary air delivery chamber is located between the secondary and tertiary compression chambers.
[0016] By adopting the above technical solution, when the gas enters the tertiary compression chamber from the secondary compression chamber, it travels a longer path, allowing the secondary compression chamber to have a larger buffer space during compression.
[0017] Preferably, the pump body has a secondary air inlet, which is connected to the second air delivery channel, and a solenoid valve is provided on the secondary air inlet.
[0018] By adopting the above technical solution, when only secondary compressed gas is needed, the solenoid valve is opened to allow the gas in the secondary compression chamber to be sent out through the secondary gas outlet.
[0019] In summary, this application has the following beneficial technical effects: after the gas enters the secondary compression stage, when the gas pressure exceeds the set required pressure, the pressure relief ball is lifted, thereby opening the pressure relief port and allowing the gas to be depressurized in the secondary compression chamber. This reduces the excessive load caused by excessive pressure during secondary compression, protects the motor, and improves the service life of the motor. Attached Figure Description
[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the overall structure of the pump body in this embodiment; Figure 2 This is a schematic diagram of the rotor's position structure in this embodiment; Figure 3 This is a schematic diagram of the compression chamber in this embodiment; Figure 4 This is a schematic diagram of the pressure relief chamber in this embodiment; Figure 5 This is a schematic diagram of the installation structure of the pressure relief ball in this embodiment; Figure 6 This is a schematic diagram of the connecting cavity in this embodiment; Figure 7 This is a schematic diagram showing all the gas flow within the body in this embodiment.
[0022] The attached diagram lists the components represented by each number as follows: 1. Pump body; 2. Rotor; 3. Motor; 4. Primary air delivery chamber; 5. Secondary compression chamber; 6. Tertiary compression chamber; 7. Quaternary compression chamber; 8. Fifth compression chamber; 9. Air outlet chamber; 10. First air delivery channel; 11. Second air delivery channel; 12. Third air delivery channel; 13. Fourth air delivery channel; 14. Pressure relief chamber; 15. Air vent; 16. Pressure relief ball; 17. Air outlet; 18. Placement ball; 19. Secondary air delivery port; 20. Pressure relief port; 21. Connecting chamber; 22. Air inlet. Detailed Implementation
[0023] 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, and 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.
[0024] The following is in conjunction with the appendix Figure 1-7 This application will be described in further detail.
[0025] Reference Figures 1-7 A multi-stage Roots vacuum pump includes a pump body 1, a rotor 2 disposed in the pump body 1, and a motor 3 for driving the rotor 2 to rotate. The rotor 2 includes a male rotor 2 and a female rotor 2. The pump body 1 is provided with a primary air supply chamber 4, a secondary compression chamber 5, a tertiary compression chamber 6, a quaternary compression chamber 7, and a quinary compression chamber 8. An exhaust chamber 9 is opened on the main body. The quinary compression chamber 8 communicates with the exhaust chamber 9. The male rotor 2 and the female rotor 2 cooperate with each other to form a set. A set of rotor 2 is disposed in each of the primary air supply chamber 4, the secondary compression chamber 5, the tertiary compression chamber 6, the quaternary compression chamber 7, and the quinary compression chamber 8. The primary air supply chamber 4 is located between the secondary compression chamber 5 and the tertiary compression chamber 6. Reference Figures 1-7 The pump body 1 has an air inlet 22, which is connected to the primary air delivery chamber 4. The rotor 2 in the primary air delivery chamber 4 is used to deliver external air into the secondary compression chamber 5. The rotor 2 in the secondary compression chamber 5 compresses the air delivered in the primary stage, and the compressed air enters the tertiary compression chamber 6. The rotor 2 in the tertiary compression chamber 6 further compresses the compressed air delivered in the secondary compression chamber 5 and then delivers it into the quaternary compression chamber 7. The rotor 2 in the quaternary compression chamber 7 further compresses the compressed air delivered in the quaternary compression chamber 6, and the rotor 2 in the quaternary and quaternary compression chambers 8 further compresses the compressed air delivered in the quaternary compression chamber 7. The compressed air is then delivered into the outlet chamber 9, thereby obtaining the required compressed air. Reference Figures 1-7 A first air supply passage 10 is provided between the primary air supply chamber 4 and the secondary compression chamber 5; a second air supply passage 11 is provided between the secondary compression chamber 5 and the tertiary compression chamber 6; a third air supply passage 12 is provided between the tertiary compression chamber 6 and the fourth compression chamber 7; and a fourth air supply passage 13 is provided between the fourth compression chamber 7 and the fifth compression chamber 8. One end of the first air supply passage 10 is connected to the lower side of the primary air supply chamber 4, and the other end is connected to the upper side of the secondary compression chamber 5; one end of the second air supply passage 11 is connected to the lower side of the secondary compression chamber 5, and the other end is connected to the upper side of the tertiary compression chamber 6; and so on. One end of the fourth air supply passage 13 is connected to the lower side of the fourth compression chamber, and the other end is connected to the upper side of the fifth compression chamber. Reference Figures 1-7The pump body 1 has a pressure relief chamber 14, and a pressure relief channel 15 is provided between the pressure relief chamber 14 and the second air supply channel 11. The pressure relief chamber 14 has a pressure relief port 20, and a pressure relief ball 16 is placed in the pressure relief port 20. The pressure in the second air supply channel 11 is F1, and the pressure of the pressure relief ball 16 on the pressure relief port 20 is F2. F2 satisfies F2=m*g, where m is the weight of the pressure relief ball 16 and g is the acceleration due to gravity. When F1>F2, the pressure relief ball 16 opens the pressure relief port 20. After the gas enters the secondary compression, when the gas pressure exceeds the set required pressure, the pressure relief ball 16 is lifted up, thereby opening the pressure relief port 20 and allowing the gas to be depressurized in the secondary compression chamber 5. This reduces the excessive load caused by excessive pressure during secondary compression, protects the motor 3, and improves the service life of the motor 3.
[0026] Reference Figures 1-7 The pressure relief port 20 is designed with a larger upper part and a smaller lower part. After the pressure relief ball 16 is lifted, the larger upper part and smaller lower part of the pressure relief port 20 can allow the pressure relief ball 16 to fully return to its original position. The pressure relief ball 16 is made of stainless steel, which reduces the corrosion of the pressure relief ball 16 when the gas comes into contact with it and improves its service life.
[0027] Reference Figures 1-7 An air outlet 17 is provided on the air outlet chamber 9. The air outlet 17 has the same structure as the pressure relief port 20. A placement ball 18 is placed on the air outlet 17. The pressure in the air outlet chamber 9 is F3, and the pressure of the placement ball 18 on the pressure relief port is F4. F4 satisfies F4=m*g, where m is the weight of the pressure relief ball 16 and g is the acceleration due to gravity. When F3>F4, the placement ball 18 opens the air outlet 17. After the gas pressure in the fourth-stage compression chamber 7 reaches the required value, the placement ball 18 is lifted up to exhaust gas.
[0028] Reference Figures 1-7 The gas in each chamber is transported from top to bottom, which facilitates the layout and avoids mutual interference between gases. The primary gas delivery chamber 4 is located between the secondary compression chamber 5 and the tertiary compression chamber 6, which allows the gas to travel a longer path when entering the tertiary compression chamber 6 from the secondary compression chamber 5, giving the secondary compression chamber 5 a larger buffer space during compression.
[0029] Reference Figures 1-7 The pump body 1 has a secondary air inlet 19, which is connected to the second air delivery channel 11. A solenoid valve (not shown in the figure) is installed on the secondary air inlet 19. When only secondary compressed gas is needed, the solenoid valve is opened to allow the gas in the secondary compression chamber 5 to be sent out through the secondary air inlet 19. The pump body has a connecting chamber 21, which is connected to an external device for conveying gas. The gas discharged from the outlet 17 enters the connecting chamber 21 and is discharged. At the same time, the gas discharged from the pressure relief port 20 also enters the connecting chamber and is discharged.
[0030] The implementation principle of this embodiment is as follows: when the pressure in the secondary chamber is greater than the pressure of the pressure relief ball 16 pressing on the pressure relief port 20, the pressure relief ball 16 opens the pressure relief port 20. After the gas enters the secondary compression, when the gas pressure exceeds the set required pressure, the pressure relief ball 16 is lifted up, thereby opening the pressure relief port 20 and allowing the gas to be depressurized in the secondary compression chamber 5. This reduces the excessive load caused by excessive pressure during secondary compression, protects the motor 3, and improves the service life of the motor 3.
[0031] During the startup phase: the pressure in the second gas inlet 11 is higher than atmospheric pressure, the pressure relief ball is pushed open, and most of the gas is directly discharged to the atmosphere from the second stage. Only a small amount of gas continues to enter the subsequent third, fourth, and fifth stages. During the low-speed operation phase: when the inlet pressure drops to a certain level and the pressure in the second gas inlet 11 is lower than atmospheric pressure, the atmospheric pressure pushes the pressure relief ball 16 back to the pressure relief port 20, and the pressure relief port 20 is closed. At this time, all the gas is compressed by the last stage (the fifth stage) and directly discharged into the atmosphere. In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.
[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A multistage Roots vacuum pump, comprising a pump body (1), a rotor (2) disposed in the pump body (1), and a motor (3) for driving the rotor (2) to rotate, wherein the rotor (2) comprises a male rotor (2) and a female rotor (2), characterized in that: The pump body (1) is provided with a primary air supply chamber (4), a secondary compression chamber (5), a tertiary compression chamber (6), a quaternary compression chamber (7), and a quinary compression chamber (8). A first air supply channel (10) is provided between the primary air supply chamber (4) and the secondary compression chamber (5), a second air supply channel (11) is provided between the secondary compression chamber (5) and the tertiary compression chamber (6), a third air supply channel (12) is provided between the tertiary compression chamber (6) and the quaternary compression chamber (7), and a fourth air supply channel (13) is provided between the quaternary compression chamber (7) and the quinary compression chamber (8). An air outlet chamber (9) is provided on the main body. The quinary compression chamber (8) is connected to the air outlet chamber (9). The primary air supply chamber (4), the secondary compression chamber (5), the tertiary compression chamber (6), the quaternary compression chamber (7), and the quinary compression chamber (8) are connected to the pump body (1). Rotors (2) are respectively installed in the cavity (5), the three-stage compression cavity (6), the four-stage compression cavity (7), and the five-stage compression cavity (8); a pressure relief cavity (14) is opened in the pump body (1), the pressure relief cavity (14) is connected to the second air supply channel (11), a pressure relief port (20) is opened on the pressure relief cavity (14), a pressure relief ball (16) is placed in the pressure relief port (20), the pressure in the second air supply channel (11) is F1, the pressure of the pressure relief ball (16) on the pressure relief port (20) is F2, the F2 satisfies F2=m*g, where m is the weight of the pressure relief ball (16) and g is the gravitational acceleration. When F1>F2, the pressure relief ball (16) opens the pressure relief port (20).
2. The multi-stage Roots vacuum pump according to claim 1, characterized in that: The pressure relief port (20) is designed with a larger upper part and a smaller lower part.
3. A multi-stage Roots vacuum pump according to claim 2, characterized in that: The pressure relief ball (16) is made of stainless steel.
4. A multi-stage Roots vacuum pump according to claim 2, characterized in that: An air outlet (17) is provided on the air outlet chamber (9). The air outlet (17) has the same structure as the pressure relief port (20). A placement ball (18) is placed on the air outlet (17). The pressure in the air outlet chamber (9) is F3. The pressure of the placement ball (18) on the pressure relief port (20) is F4. F4 satisfies F4=m*g, where m is the weight of the pressure relief ball (16) and g is the gravitational acceleration. When F3>F4, the placement ball (18) opens the air outlet (17).
5. A multi-stage Roots vacuum pump according to claim 4, characterized in that: The first air supply channel (10) is connected at one end to the lower side of the first-stage air supply chamber (4) and at the other end to the upper side of the second-stage compression chamber (5); the second air supply channel (11) is connected at one end to the lower side of the second-stage compression chamber (5) and at the other end to the upper side of the third-stage compression chamber (6); and so on, the fourth air supply channel (13) is connected at one end to the lower side of the fourth compression chamber and at the other end to the upper side of the fifth compression chamber.
6. A multi-stage Roots vacuum pump according to claim 5, characterized in that: The primary air delivery chamber (4) is located between the secondary compression chamber (5) and the tertiary compression chamber (6).
7. A multi-stage Roots vacuum pump according to claim 5, characterized in that: The pump body (1) is provided with a secondary air inlet (19), which is connected to the second air supply channel (11). A solenoid valve is provided on the secondary air inlet (19).