A multi-stage high-temperature roots vacuum pump with a hollow rotor

Abstract

The utility model discloses a kind of multistage high-temperature Roots vacuum pumps with hollow rotor, belong to vacuum pump technical field, including pump body assembly, the pump body assembly includes the upper shell and lower shell fixed by fixed bolt, the first stage pressurizing chamber, second stage pressurizing chamber and third stage pressurizing chamber are separated in the pump body assembly inner portion;Two mutually matched rotors are provided in each pressurizing chamber, rotor is made of special alloy material, and it is hollow structure inside, and pump body assembly is equipped with rotating rod, rotating rod is supported by bearing, and sequentially passes all rotors;The pump body assembly is equipped with the conveying channel of intercommunication adjacent pressurizing chamber, and first adjusting channel and second adjusting channel between adjacent conveying channel, and the upper shell is equipped with adjusting assembly for controlling the opening and closing of adjusting channel.The utility model provides Roots vacuum pump that can be long-term operation under high temperature, reduce energy consumption simultaneously, and can optimize its pumping performance according to working condition.

Description

Technical Field

[0001] This utility model relates to the field of vacuum pump technology, and in particular to a multi-stage high-temperature Roots vacuum pump with a hollow rotor. Background Technology

[0002] Vacuum technology plays a vital role in modern industry, especially in high-tech fields such as semiconductor manufacturing, photovoltaic industry, flat panel display production and fine chemicals. In these applications, Roots vacuum pumps are widely used as main pumps or booster pumps in vacuum systems due to their advantages such as high pumping speed, oil-free operation and simple and reliable structure in the medium and low vacuum range.

[0003] Traditional Roots pump rotors are typically solid metal structures. When such massive solid rotors are heated to temperatures as high as 150°C, significant and uneven thermal expansion becomes a fatal problem. Even slight deformation can cause the disappearance of the micron-level precision operating gaps between rotors or between the rotor and the pump casing, resulting in scraping, collisions, or even seizure. Furthermore, the large mass and rotational inertia of solid rotors not only mean that more electrical energy is required during startup and operation, but also that the transmission system (such as bearings and synchronous gears) will be subjected to greater loads and impacts, affecting the long-term operational stability and lifespan of the pump. Utility Model Content

[0004] The purpose of this invention is to provide a Roots vacuum pump that can operate at high temperatures for extended periods while reducing energy consumption and optimizing its pumping performance according to operating conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a multi-stage high-temperature Roots vacuum pump with a hollow rotor, comprising a pump body assembly, wherein the pump body assembly comprises an upper shell and a lower shell fixed by fixing bolts, and the pump body assembly is internally divided into a first-stage pressurization chamber, a second-stage pressurization chamber and a third-stage pressurization chamber; Each pressurization chamber is equipped with two rotors that rotate in coordination with each other. The rotors are made of special alloy material and have a hollow internal structure. The pump body assembly is equipped with a rotating rod, which is supported by bearings and passes through all the rotors in sequence. The pump assembly is provided with a delivery channel connecting adjacent booster chambers, and a first adjustment channel and a second adjustment channel located between adjacent delivery channels. The upper housing is provided with an adjustment component for controlling the opening and closing of the adjustment channels.

[0006] As a further description of the above technical solution: the top of the upper housing is provided with a gas input pipe communicating with the first-stage pressurization chamber, and the bottom of the lower housing is provided with a gas output pipe communicating with the third-stage pressurization chamber.

[0007] As a further description of the above technical solution: the conveying channel includes a first conveying channel connecting the bottom of the first-stage pressurization chamber and the top of the second-stage pressurization chamber, and a second conveying channel connecting the bottom of the second-stage pressurization chamber and the top of the third-stage pressurization chamber.

[0008] As a further description of the above technical solution: several limiting grooves are evenly distributed circumferentially on the inner wall of the rotor center hole, and a limiting block that cooperates with the limiting groove is fixed on the outer ring of the rotating rod located in the center hole.

[0009] As a further description of the above technical solution: it also includes a synchronizing gear disposed at the end of the rotating rod, and the synchronizing gears on the two rotating rods mesh with each other.

[0010] As a further description of the above technical solution: the adjustment assembly includes a sealing plate, a return spring, and an adjustment screw that are slidably disposed in the adjustment channel; One end of the reset spring is fixed to the boss on the inner wall of the adjustment channel, and the other end is connected to the sealing plate; the adjustment screw passes through the upper housing and abuts against the sealing plate.

[0011] As a further description of the above technical solution: the reset spring pushes the sealing plate upward under normal conditions to open the adjustment channel, and when the adjustment screw is tightened, the sealing plate moves downward to close the adjustment channel.

[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are: 1. The rotor adopts a hollow structure and uses special alloy materials with high temperature resistance and low thermal expansion coefficient. The hollow design greatly reduces the rotor weight, which allows the rotor to maintain extremely high dimensional accuracy and stability at high temperatures. It effectively suppresses thermal deformation, thereby ensuring the long-term trouble-free operation of the vacuum pump under harsh high-temperature conditions and significantly improving the reliability and service life of the equipment.

[0013] 2. Because the rotor has a hollow structure, its weight is much lower than that of a solid rotor of the same size, and the moment of inertia is also significantly reduced. This reduces the load on the motor during startup and operation, saves energy consumption, and at the same time reduces the impact and wear on the bearings and synchronous gears. This also makes the pump run more smoothly with less vibration and noise.

[0014] 3. The adjustable bypass channel and adjustment components enable a single pump body to adapt to the needs of different working stages, thus optimizing the overall pumping efficiency. Attached Figure Description

[0015] Figure 1 A front view of the present invention is shown; Figure 2 A perspective view of the upper housing of this utility model is shown; Figure 3 A cross-sectional view of the rotor of this utility model is shown; Figure 4 A cross-sectional view of the pump body assembly of this utility model is shown; Figure 5 A perspective view of the rotor and rotating rod of this utility model is shown; Figure 6 A perspective view of the present invention is shown.

[0016] Legend: 10. Upper housing; 101. Input pipe; 11. Lower housing; 111. Output pipe; 12. Fixing bolt; 13. Rotor; 131. Restricting groove; 14. Rotating rod; 141. Restricting block; 15. Bearing; 16. Synchronous gear; 17. First conveying channel; 18. Second conveying channel; 19. First adjusting channel; 20. Second adjusting channel; 21. Sealing plate; 22. Return spring; 23. Adjusting screw. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0018] Please see Figures 1-6 This utility model provides a technical solution: a multi-stage high-temperature Roots vacuum pump with a hollow rotor, including an upper shell 10 and a lower shell 11. The upper shell 10 and the lower shell 11 are fastened together by a number of high-strength fixing bolts 12, forming a pump assembly with good sealing and pressure resistance.

[0019] The pump assembly is internally divided into three independent chambers connected in series along the gas flow direction through an integrated processing technology. These are the first-stage booster chamber, the second-stage booster chamber, and the third-stage booster chamber. The gas inlet is located at the beginning of the pump body flow channel. Specifically, an integrally formed gas input pipe 101 is provided at the top of the upper housing 10, which is directly connected to the first-stage booster chamber. The gas outlet is located at the end of the pump body flow channel. Specifically, an integrally formed gas output pipe 111 is provided at the bottom of the lower housing 11, which is connected to the third-stage booster chamber.

[0020] In each independent chamber, two rotors 13 are arranged in parallel and can cooperate to rotate synchronously in opposite directions. To adapt to the high temperature and high pressure environment brought about by multi-stage pressurization, the rotors 13 are made of special alloy materials with high strength, excellent heat resistance and low thermal expansion coefficient, and are precision machined.

[0021] Crucially, the rotor 13 is designed with a hollow structure inside. This hollow design, combined with the characteristics of special alloy materials, greatly improves the thermal stress distribution of the rotor 13 at high temperatures (such as 150°C), effectively suppresses thermal deformation, and ensures micron-level precision gaps between rotors 13 and between rotors 13 and the inner wall of the pump cavity, thereby achieving long-term stable operation of the equipment under high-temperature conditions.

[0022] To drive the rotor 13, at least two parallel rotating rods 14 are provided. The rotating rods 14 pass through the upper housing 10 and the lower housing 11, and pass through all the rotors 13 in the three-stage chamber in sequence. The rotating rods 14 are radially and axially positioned and supported by high-precision, heavy-duty bearings 15 set on the housing to ensure smooth rotation and high coaxiality.

[0023] Each rotor 13 has a central axial through-hole. The inner wall of the hole has several circumferentially distributed limiting grooves 131. Correspondingly, in the part of the rotating rod 14 located in the central hole of the rotor 13, the outer ring is fixed with limiting blocks 141 that match the limiting grooves 131 by means of fixed welding or key connection. When the rotating rod 14 rotates under the drive of external force, the torque is transmitted to the rotor 13 through the engagement of the limiting blocks 141 and the limiting grooves 131, driving it to rotate synchronously.

[0024] To achieve synchronous rotation of the two rotors 13 in opposite directions in each chamber without contact between the blades, a pair of meshing synchronous gears 16 are fixedly fitted on the outer rings of the two rotating rods 14 at one end of the pump assembly. The tooth surfaces of the synchronous gears 16 are precision ground to ensure minimal backlash during transmission, thereby ensuring that the rotors 13 maintain a precise phase relationship throughout the entire rotation cycle. This is the core guarantee for achieving oil-free and contactless operation of the Roots pump.

[0025] In order to transport gas from the previous stage chamber to the next stage chamber, an integrally cast interstage transport channel is provided inside the upper shell 10 and the lower shell 11. Specifically, the bottom of the first stage pressurization chamber is connected to the top of the second stage pressurization chamber through two parallel first transport channels 17, and the bottom of the second stage pressurization chamber is connected to the top of the third stage pressurization chamber through two parallel second transport channels 18.

[0026] Between the two first conveying channels 17, there is a first adjustment channel 19, and between the two second conveying channels 18, there is a second adjustment channel 20. These two adjustment channels also serve to connect the adjacent two-stage chambers.

[0027] An adjustment assembly is provided on the upper housing 10 to control the opening and closing of the adjustment channels. The adjustment assembly includes a sealing plate 21 that is slidably disposed in the inner wall of the first adjustment channel 19 and the second adjustment channel 20. A boss is provided on the inner wall of the adjustment channel, and a plurality of return springs 22 are installed on the boss. One end of the return spring 22 is fixedly connected to the boss, and the other end is fixedly connected to the lower surface of the sealing plate 21 to provide a tendency for the sealing plate 21 to return to its original position. An adjustment screw 23 is provided at a corresponding position on the top of the upper housing 10. The lower end of the adjustment screw 23 passes through the upper housing 10 and abuts against the upper surface of the sealing plate 21.

[0028] Work steps: In the initial or high-pressure stage, the adjusting screw 23 is in a loose state. Under the action of the return spring 22, the sealing plate 21 is pushed upward, so that the first adjusting channel 19 and the second adjusting channel 20 are in the open state. When the gas is discharged from the first stage to the second stage, it will flow through the first conveying channel 17 and the first adjusting channel 19 at the same time. When it is discharged from the second stage to the third stage, it will flow through the second conveying channel 18 and the second adjusting channel 20 at the same time. At this time, the gas flow cross-sectional area is large and the flow resistance is small, which is conducive to the pump starting and pumping quickly and smoothly under high inlet pressure, and avoids overload of the front stage.

[0029] When the pump operates in the lower pressure range, in order to improve the ultimate vacuum and compression ratio, the operator tightens the adjusting screw 23. The adjusting screw 23 moves down, pushing the sealing plate 21 to slide down against the elastic force of the return spring 22 until it completely closes the first adjusting channel 19 and the second adjusting channel 20. At this time, the interstage gas delivery depends entirely on the first delivery channel 17 and the second delivery channel 18. This design enhances the pressure difference between stages and effectively prevents the backflow of high-pressure gas to the low-pressure stage.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A multi-stage high-temperature Roots vacuum pump with a hollow rotor, characterized in that, The pump assembly includes an upper housing (10) and a lower housing (11) fixed by fixing bolts (12), and the pump assembly is internally divided into a first-stage pressurization chamber, a second-stage pressurization chamber and a third-stage pressurization chamber; Each pressurization chamber is equipped with two rotors (13) that rotate in coordination with each other. The rotors (13) are made of special alloy material and have a hollow internal structure. The pump body assembly is equipped with a rotating rod (14), which is supported by a bearing (15) and passes through all the rotors (13) in sequence. The pump assembly is provided with a delivery channel connecting adjacent booster chambers, and a first adjustment channel (19) and a second adjustment channel (20) located between adjacent delivery channels. The upper housing (10) is provided with an adjustment component for controlling the opening and closing of the adjustment channels.

2. A multi-stage high-temperature Roots vacuum pump with a hollow rotor according to claim 1, characterized in that: The upper housing (10) has a gas input pipe (101) at the top that communicates with the first-stage pressurization chamber, and the lower housing (11) has a gas output pipe (111) at the bottom that communicates with the third-stage pressurization chamber.

3. A multi-stage high-temperature Roots vacuum pump with a hollow rotor according to claim 1, characterized in that: The delivery channels include a first delivery channel (17) connecting the bottom of the first-stage pressurization chamber to the top of the second-stage pressurization chamber, and a second delivery channel (18) connecting the bottom of the second-stage pressurization chamber to the top of the third-stage pressurization chamber.

4. A multi-stage high-temperature Roots vacuum pump with a hollow rotor according to claim 1, characterized in that: The inner wall of the central hole of the rotor (13) is evenly distributed with several limiting grooves (131) along the circumference, and the outer ring of the rotating rod (14) located in the central hole is fixed with a limiting block (141) that cooperates with the limiting groove (131).

5. A multi-stage high-temperature Roots vacuum pump with a hollow rotor according to claim 1, characterized in that: It also includes a synchronizing gear (16) located at the end of the rotating rod (14), and the synchronizing gears (16) on the two rotating rods (14) mesh with each other.

6. A multi-stage high-temperature Roots vacuum pump with a hollow rotor according to claim 1, characterized in that: The adjustment assembly includes a sealing plate (21) slidably disposed in the adjustment channel, a return spring (22) and an adjustment screw (23); One end of the reset spring (22) is fixed to the boss on the inner wall of the adjustment channel, and the other end is connected to the sealing plate (21); the adjustment screw (23) passes through the upper housing (10) and abuts against the sealing plate (21).

7. A multi-stage high-temperature Roots vacuum pump with a hollow rotor according to claim 6, characterized in that: The reset spring (22) normally pushes the sealing plate (21) upward to open the adjustment channel. When the adjustment screw (23) is tightened, the sealing plate (21) moves downward to close the adjustment channel.

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