CN118257724A - Multistage Roots vacuum pump with adjustable compression ratio - Google Patents
Multistage Roots vacuum pump with adjustable compression ratio Download PDFInfo
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- CN118257724A CN118257724A CN202410290013.0A CN202410290013A CN118257724A CN 118257724 A CN118257724 A CN 118257724A CN 202410290013 A CN202410290013 A CN 202410290013A CN 118257724 A CN118257724 A CN 118257724A
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- 230000006835 compression Effects 0.000 title claims abstract description 35
- 238000007906 compression Methods 0.000 title claims abstract description 35
- 230000001360 synchronised effect Effects 0.000 claims abstract description 41
- 238000000605 extraction Methods 0.000 claims description 18
- 230000000694 effects Effects 0.000 abstract description 3
- 238000005086 pumping Methods 0.000 description 13
- 238000007789 sealing Methods 0.000 description 11
- 239000010410 layer Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000009434 installation Methods 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 239000011229 interlayer Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
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Abstract
The invention provides a multi-stage Roots vacuum pump with an adjustable compression ratio, which comprises an air inlet and an air outlet, wherein the air inlet is communicated with a first-stage pump cavity; a first-stage rotor is arranged in the first-stage pump cavity, a second-stage rotor is arranged in the second-stage pump cavity, and the first-stage rotor and the second-stage rotor are respectively arranged on corresponding pump shafts; one end of each pump shaft is provided with a synchronous gear, the other end of one pump shaft corresponding to the first-stage rotor is provided with a speed change gear, and correspondingly, the other end of one pump shaft corresponding to the second-stage rotor is also provided with a speed change gear; oil tanks are respectively arranged beside the speed change gear and the synchronous gear. The technical effect of the invention is obviously better than the prior art because the technical means that only one rotor (impeller) and a plurality of rotor groups from top to bottom are arranged on the same main shaft and the compression ratio of the rotor groups is adjustable are adopted.
Description
Technical Field
The invention belongs to the technical field of vacuum pump manufacturing, and particularly relates to a multistage Roots vacuum pump with an adjustable compression ratio.
Background
The multistage Roots vacuum pump disclosed in the patent application publication No. CN114576165A comprises a cavity and two rotors, wherein the cavity comprises an air inlet cavity, a first-stage compression cavity and a second-stage compression cavity which are sequentially communicated, the number of the first-stage compression cavities is two, and the two first-stage compression cavities are in a symmetrical form relative to the middle plane of the two first-stage compression cavities; the two rotors are installed in the cavity, the two rotors are meshed with each other and synchronously rotate reversely, the rotors comprise an air inlet rotor, a first-stage Roots rotor and a second-stage Roots rotor, and the air inlet rotor, the first-stage Roots rotor and the second-stage Roots rotor are respectively located in the air inlet cavity, the first-stage compression cavity and the second-stage compression cavity. The two first-stage compression chambers are in a symmetrical form relative to the middle plane of the two first-stage compression chambers, so that the two first-stage Roots rotors of the rotors are also in a symmetrical form relative to the middle plane of the two first-stage Roots rotors.
Generally, the multistage Roots vacuum pump disclosed in the patent application No. CN114576165A can reduce the volume of the equipment, and effectively reduce the axial force born by a rotor (impeller). However, the invention also has obvious technical defects, which are specifically shown as follows:
First, the greatest technical disadvantage of the invention is that a plurality of rotors (impellers) share a main shaft, and the length of the main shaft can only be limited to a small range for use because the main shaft bears radial force generated when the rotors work at the same time. In the case of a smaller length spindle, arranging a plurality of impellers in parallel on the spindle means that each impeller can be distributed in a short length, which results in a small pumping cavity of the Roots pump. Because the whole pumping capacity of the Roots pump is sucked from the first-stage rotor, the pumping capacity of the whole pump is already determined by the pumping capacity of the first-stage rotor, and the second-stage rotor and the third-stage rotor only increase the compression ratio of the Roots pump, the scheme that a plurality of rotors (impellers) share one main shaft can cause the pumping capacity of the Roots pump to be small.
Secondly, the invention divides the second rotor and the third rotor into two halves, and then the two halves are symmetrically distributed at the two ends of the first rotor and are divided into two ends for exhaust, so that the axial force of the rotor can be reduced, but another more serious defect is caused, namely, the structure of the single-side 3 impellers is changed into the structure of the single-side 5 impellers, the number of parts is increased, the structure is more complex, the sealing plate between each impeller occupies the length space on the main shaft, the length of the arrangeable impellers is further reduced, and the exhaust quantity is smaller than that of the structure of the traditional single-side 3 impellers. In addition, in the case where a plurality of impellers are coaxial, the greater the number of impellers, the greater the difficulty of installation, which is due to: each impeller is required to be provided with a sealing partition plate for sealing, and the smaller the gap between the impeller and the sealing partition plate is, the better the sealing performance is, and the smaller the internal leakage amount is when the pump works. The axial position of the impeller on the main shaft is fixed, but the deviation of each impeller can occur in the processing or mounting process, the more the number of the impellers is, the deviation of the processing or mounting of each impeller can be mutually contained, the more difficult the clearance between the impeller and the sealing plate is to control, and the problem of interference friction between the impeller and the sealing plate is easy to occur. Especially, because the part generates heat and expands in the working process, the more parts on the shaft are, the more easily the problem of clamping is generated.
Thirdly, although the invention adopts a technical means of multistage layered compression, the compression ratio between layers is fixed, which makes the invention difficult to be suitable for complex and variable working conditions.
Disclosure of Invention
The invention aims to overcome the technical defects that the extraction quantity of the Roots pump is small due to the fact that a plurality of rotors (impellers) are arranged on the same main shaft in the prior art, the installation structure is complex due to the fact that the impellers and matched components share the main shaft, and the interlayer compression ratio is not adjustable, so that complicated and variable working conditions are difficult to apply.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
The multi-stage Roots vacuum pump with the adjustable compression ratio comprises an air inlet and an air outlet, wherein the air inlet is communicated with a first-stage pump cavity, the first-stage pump cavity is communicated with a second-stage pump cavity below the first-stage pump cavity, and the second-stage pump cavity is communicated with the air outlet; a first-stage rotor is arranged in the first-stage pump cavity, a second-stage rotor is arranged in the second-stage pump cavity, and the first-stage rotor and the second-stage rotor are respectively arranged on corresponding main shafts; bearings are arranged at two ends close to each main shaft, and shaft sealing components are arranged at the contact positions of each main shaft and the bearings;
One end of each main shaft is provided with a synchronous gear, and the synchronous gear is positioned at the outer side of a bearing at the end; the other end of one main shaft corresponding to the first-stage rotor is provided with a speed change gear which is positioned at the outer side of a bearing at the end;
correspondingly, the other end of one main shaft corresponding to the second-stage rotor is also provided with a speed change gear, and the speed change gear is positioned at the outer side of the bearing at the end; an oil tank is respectively arranged beside the speed change gear and the synchronous gear;
The number of the first-stage rotors is two, the two first-stage rotors are arranged in the first-stage pump cavity in parallel, and when the synchronous rotary pump works, the two first-stage rotors realize synchronous reverse rotation through the mutual engagement of synchronous gears arranged on respective main shafts, wherein one first-stage rotor is driven by a motor to rotate, and the other first-stage rotor is driven by the synchronous gears to rotate;
correspondingly, the number of the second-stage rotors is two, the two second-stage rotors are arranged in the second-stage pump cavity in parallel, and synchronous reverse rotation is realized through the mutual engagement of synchronous gears arranged on the respective main shafts;
In the two first-stage rotors, a speed change gear is arranged on a main shaft where one first-stage rotor driven by a motor is positioned, and correspondingly, a speed change gear is also arranged on a main shaft where one second-stage rotor positioned right below the first-stage rotor is positioned, when the motor drives the first-stage rotor to rotate, the second-stage rotor positioned right below the motor is driven to reversely rotate through the mutual meshing of the upper speed change gear and the lower speed change gear, and the driven second-stage rotor drives the second-stage rotor positioned right below the motor to reversely rotate synchronously through a synchronous gear at the other end of the driven second-stage rotor.
On the basis of the technical scheme, the invention can be added with the following technical means so as to better or more pertinently solve the technical problems to be solved by the invention:
The air extraction rate of the first-stage rotor is 1.5-3 times of the air extraction rate of the second-stage rotor. Specifically, the pumping speed of the first stage rotor is set to be 1.5-3 times of the pumping speed of the second stage rotor through the adjustment of the upper and lower variable gears, so that the interlayer compression ratio of the first stage pump cavity and the first stage pump cavity is adjusted
Further, still be provided with third level pump chamber in the below of second level pump chamber, second level pump chamber and the third level pump chamber intercommunication of its below, third level pump chamber and the gas vent intercommunication of its below are equipped with two tertiary rotors in the third level pump chamber, synchronous gear is installed respectively to the same end of two tertiary rotor place main shafts, through synchronous gear's intermeshing, realize synchronous counter-rotation, the speed change gear is installed to the other end of one of them tertiary rotor place main shaft, during operation, through this speed change gear with the speed change gear intermesh on the main shaft at second level rotor place, the second level rotor can drive this tertiary rotor counter-rotation.
Further, the pumping speed of the second-stage rotor is 1.5-3 times of that of the third-stage rotor.
Further, a fourth-stage pump cavity is further arranged below the third-stage pump cavity, the third-stage pump cavity is communicated with the fourth-stage pump cavity below the third-stage pump cavity, the fourth-stage pump cavity is communicated with an exhaust port below the third-stage pump cavity, two fourth-stage rotors are arranged in the fourth-stage pump cavity, a synchronous gear is arranged at the same end of a main shaft where the two fourth-stage rotors are located, synchronous reverse rotation is achieved through mutual engagement of the synchronous gears, a speed change gear is arranged at the other end of the main shaft where one fourth-stage rotor is located, and in operation, the speed change gear is engaged with the speed change gear on the main shaft where the third-stage rotor is located through the speed change gear, and the third-stage rotor can drive the fourth-stage rotor to reversely rotate.
Further, the pumping speed of the third-stage rotor is 1.5-3 times of that of the fourth-stage rotor.
Compared with the prior art, the invention has the main beneficial effects as follows:
Firstly, because the whole machine extraction quantity of the Roots pump is sucked from the first-stage rotor set, the extraction capacity of the first-stage rotor set already determines the extraction capacity of the whole pump, and the second-stage rotor set and the third-stage rotor set only have the effect of increasing the compression ratio of the Roots pump, therefore, the invention adopts the technical scheme that only one impeller (rotor) is arranged on each main shaft, the length of the impeller can occupy the whole length of the main shaft capable of bearing the load, and the extraction capacity of the whole pump can be greatly improved. Specifically, compared with a structure with a plurality of coaxial impellers, the pumping volume of a single impeller is obviously increased, and the total pumping capacity is improved by 2-6 times compared with a structure with a plurality of coaxial impellers with the same diameter.
Second, only one impeller is arranged on each main shaft, the processing and installation difficulty is obviously lower than that of a coaxial structure of a plurality of impellers, and the gap between the impellers and the sealing plate is easier to control. The production and processing difficulty is reduced, and meanwhile, the failure rate of impeller blocking is reduced, so that the Roots pump works more stably and reliably.
Thirdly, the compression ratio between each layer can be adjusted by adjusting the speed ratio of the speed change gear, the adjusting method is flexible, and the adaptability to complex working conditions is higher, so that the working efficiency is higher.
Drawings
FIG. 1 is a schematic view of a vertical section of an embodiment of the present invention;
FIG. 2 is a schematic view of the horizontal section A-A of FIG. 1;
Fig. 3 is a partial enlarged view of fig. 2.
In the figure:
1-a first stage rotor; 2-a second stage rotor;
3-an air inlet; 4, an exhaust port;
5-a speed change gear; 6-synchronous gears;
7-a shaft seal member; 8, bearing;
9-an oil tank.
Detailed Description
In order to facilitate a more complete understanding of the technical solution of the present invention and its working principle by a person skilled in the art, an embodiment of the present invention is described below with reference to the accompanying drawings.
As shown in fig. 1 and fig. 2 and 3 in combination, the multi-stage Roots vacuum pump with adjustable compression ratio comprises an air inlet 3 and an air outlet 4, wherein the air inlet 3 is communicated with a first-stage pump cavity, the first-stage pump cavity is communicated with a second-stage pump cavity below the first-stage pump cavity, and the second-stage pump cavity is communicated with the air outlet 4; a first-stage rotor 1 is arranged in the first-stage pump cavity, a second-stage rotor 2 is arranged in the second-stage pump cavity, and the first-stage rotor 1 and the second-stage rotor 2 are respectively arranged on corresponding main shafts. Bearings 8 are arranged at two ends close to each main shaft (the main shafts are sleeved on the bearings 8 close to the left end and the right end of the main shaft, two bearings 8 corresponding to each main shaft are arranged), and shaft sealing parts 7 are arranged at the contact positions of each main shaft and the bearings 8 and are used for enabling a pump cavity where the main shaft is positioned to be in a closed state. At one end (left end in the drawing) of each spindle, a synchronizing gear 6 is mounted, the synchronizing gear 6 being located outside a bearing 8 at that end. A speed change gear 5 is arranged at the other end (right end in the figure) of one main shaft corresponding to the first-stage rotor 1, and the speed change gear 5 is positioned outside a bearing 8 at the end; accordingly, a speed change gear 5 is also mounted on the other end (right end in the drawing) of one main shaft corresponding to the second-stage rotor 2, and the speed change gear 5 is located outside the bearing 8 at that end. An oil tank 9 is disposed beside each of the speed change gear 5 and the synchronizing gear 6.
As shown in fig. 2, the number of the first-stage rotors 1 is two, the two first-stage rotors 1 are arranged in parallel in the first-stage pump cavity (the two first-stage rotors 1 form a first-stage rotor group), and when in operation, the two first-stage rotors 1 realize synchronous reverse rotation through the mutual engagement of the synchronous gears 6 arranged on respective main shafts, wherein one first-stage rotor 1 is driven to rotate by a motor, and the other first-stage rotor 1 is driven to rotate by the transmission of the synchronous gears 6. Correspondingly, the number of the second-stage rotors 2 is also two, the two second-stage rotors 2 are arranged in the second-stage pump cavity in parallel (the two second-stage rotors 1 form a second-stage rotor group), and synchronous reverse rotation is realized through the mutual engagement of the synchronous gears 6 arranged on the respective main shafts. In the two first-stage rotors 1, a speed change gear 5 is arranged on a main shaft of one first-stage rotor 1 driven by a motor, and correspondingly, a speed change gear 5 is also arranged on a main shaft of one second-stage rotor 2 positioned right below the first-stage rotor 1, when the motor drives the first-stage rotor 1 to rotate, the two speed change gears 5 are meshed with each other to drive the second-stage rotor 2 right below the motor to reversely rotate, and the driven second-stage rotor 2 drives the second-stage rotor of the other second-stage rotor to reversely rotate relative to the driven second-stage rotor through a synchronous gear 6 at the other end of the driven second-stage rotor. By adopting the technical means of the speed change gear 5, the invention can adjust the rotating speeds of the first-stage rotor 1 and the second-stage rotor 2 according to actual needs, thereby adjusting the interlayer compression ratio.
In addition, in the actual implementation process of the present invention, the first stage rotor, the second stage rotor, the third stage rotor, and even the fourth stage rotor may be disposed from top to bottom according to actual needs, and the same stage rotor is still two (i.e., the first stage rotor set, the second stage rotor set, the third stage rotor set, and even the fourth stage rotor set are respectively formed). The motor can drive the multi-stage rotors to rotate through the meeting meshing of the speed change gears arranged at the same end of the main shaft where the first-stage rotor, the second-stage rotor, the third-stage rotor and the fourth-stage rotor are positioned, and in the same-stage (group) rotor, one rotor can drive the other rotor to synchronously and reversely rotate through the meeting meshing of the synchronous gears. In addition, in the process of implementing the invention, through the adjustment of the upper and lower adjacent speed change gears, the pumping speed of the upper stage rotor (the upper layer rotor) can be set to be 1.5-3 times of the pumping speed of the lower stage rotor (the lower layer rotor), thereby realizing multistage layered compression. Of course, the speed ratio of the speed change gear can be adjusted according to the working condition, namely, the compression ratio between layers can be further adjusted through the change of the rotation speeds of the rotors of different levels.
In general, the technical effect of the invention is obviously better than that of the technical proposal disclosed in the patent application No. CN114576165A because the technical means that only one rotor (impeller) and a plurality of rotor groups from top to bottom are arranged on the same main shaft and the compression ratio is adjustable are adopted, and the specific reasons are as follows:
Firstly, the whole machine extraction quantity of the Roots pump is sucked from a first-stage rotor set, the extraction volume of the first-stage rotor set determines the extraction capacity of the whole pump, the second-stage rotor set, the third-stage rotor set and even the fourth-stage rotor set only increase the compression ratio of the Roots pump, and the multistage Roots pump is characterized in that only one impeller is arranged on each main shaft, the length of the impeller can occupy the whole length of the main shaft capable of bearing load, compared with a coaxial structure of a plurality of impellers, the extraction volume of a single impeller is obviously increased, and the total extraction capacity is improved by 2-6 times compared with a coaxial structure of a plurality of impellers with the same diameter.
Secondly, only one impeller is arranged on each main shaft, the processing and installation difficulty is obviously lower than that of a plurality of coaxial impellers, and the gap between the impeller and the sealing plate is easier to control, so that the production and processing difficulty of the Roots pump is reduced, the failure rate of the impeller blocking is reduced, and the working process of the Roots pump is more stable and reliable.
Thirdly, by configuring a multi-stage (layer) rotor set, the compression ratio of the Roots pump is increased (the specific ratio can be adjusted according to actual needs), so that complex and variable working conditions can be more effectively dealt with.
Claims (6)
1. The multi-stage Roots vacuum pump with the adjustable compression ratio comprises an air inlet and an air outlet, wherein the air inlet is communicated with a first-stage pump cavity, the first-stage pump cavity is communicated with a second-stage pump cavity below the first-stage pump cavity, and the second-stage pump cavity is communicated with the air outlet; a first-stage rotor is arranged in the first-stage pump cavity, a second-stage rotor is arranged in the second-stage pump cavity, and the first-stage rotor and the second-stage rotor are respectively arranged on corresponding main shafts; bearing is all disposed at the both ends that are close to every main shaft, all is provided with shaft seal part at every main shaft and the contact department of bearing, its characterized in that:
One end of each main shaft is provided with a synchronous gear, and the synchronous gear is positioned at the outer side of a bearing at the end; the other end of one main shaft corresponding to the first-stage rotor is provided with a speed change gear which is positioned at the outer side of a bearing at the end;
correspondingly, the other end of one main shaft corresponding to the second-stage rotor is also provided with a speed change gear, and the speed change gear is positioned at the outer side of the bearing at the end; an oil tank is respectively arranged beside the speed change gear and the synchronous gear;
The number of the first-stage rotors is two, the two first-stage rotors are arranged in the first-stage pump cavity in parallel, and when the synchronous rotary pump works, the two first-stage rotors realize synchronous reverse rotation through the mutual engagement of synchronous gears arranged on respective main shafts, wherein one first-stage rotor is driven by a motor to rotate, and the other first-stage rotor is driven by the synchronous gears to rotate;
correspondingly, the number of the second-stage rotors is two, the two second-stage rotors are arranged in the second-stage pump cavity in parallel, and synchronous reverse rotation is realized through the mutual engagement of synchronous gears arranged on the respective main shafts;
In the two first-stage rotors, a speed change gear is arranged on a main shaft where one first-stage rotor driven by a motor is positioned, and correspondingly, a speed change gear is also arranged on a main shaft where one second-stage rotor positioned right below the first-stage rotor is positioned, when the motor drives the first-stage rotor to rotate, the second-stage rotor positioned right below the motor is driven to reversely rotate through the mutual meshing of the upper speed change gear and the lower speed change gear, and the driven second-stage rotor drives the second-stage rotor positioned right below the motor to reversely rotate synchronously through a synchronous gear at the other end of the driven second-stage rotor.
2. The adjustable compression ratio multi-stage roots vacuum pump of claim 1, wherein: the air extraction rate of the first-stage rotor is 1.5-3 times of the air extraction rate of the second-stage rotor.
3. The adjustable compression ratio multi-stage roots vacuum pump of claim 1, wherein: the lower part of the second-stage pump cavity is also provided with a third-stage pump cavity, the second-stage pump cavity is communicated with a third-stage pump cavity below the second-stage pump cavity, the third-stage pump cavity is communicated with an exhaust port below the second-stage pump cavity, two third-stage rotors are arranged in the third-stage pump cavity, synchronous gears are respectively arranged at the same ends of the spindles where the two third-stage rotors are located, synchronous reverse rotation is realized through the mutual engagement of the synchronous gears, and a speed change gear is arranged at the other end of the spindle where one third-stage rotor is located.
4. A multi-stage roots vacuum pump with adjustable compression ratio according to claim 3, wherein: the air extraction rate of the second-stage rotor is 1.5-3 times of the air extraction rate of the third-stage rotor.
5. A multi-stage roots vacuum pump with adjustable compression ratio according to claim 3, wherein: the lower part of the third-stage pump cavity is also provided with a fourth-stage pump cavity, the third-stage pump cavity is communicated with a fourth-stage pump cavity below the third-stage pump cavity, the fourth-stage pump cavity is communicated with an exhaust port below the third-stage pump cavity, two fourth-stage rotors are arranged in the fourth-stage pump cavity, synchronous gears are arranged at the same end of a main shaft where the two fourth-stage rotors are positioned, synchronous reverse rotation is realized through the mutual engagement of the synchronous gears, a speed change gear is arranged at the other end of the main shaft where one fourth-stage rotor is positioned, and in operation, the speed change gear is meshed with the speed change gear on the main shaft where the third-stage rotor is positioned, and the third-stage rotor can drive the fourth-stage rotor to reversely rotate.
6. The adjustable compression ratio multi-stage roots vacuum pump of claim 5, wherein: the air extraction rate of the third-stage rotor is 1.5-3 times of the air extraction rate of the fourth-stage rotor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410290013.0A CN118257724A (en) | 2024-03-14 | 2024-03-14 | Multistage Roots vacuum pump with adjustable compression ratio |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410290013.0A CN118257724A (en) | 2024-03-14 | 2024-03-14 | Multistage Roots vacuum pump with adjustable compression ratio |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118257724A true CN118257724A (en) | 2024-06-28 |
Family
ID=91612133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410290013.0A Pending CN118257724A (en) | 2024-03-14 | 2024-03-14 | Multistage Roots vacuum pump with adjustable compression ratio |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118257724A (en) |
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2024
- 2024-03-14 CN CN202410290013.0A patent/CN118257724A/en active Pending
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