CN209818301U - Multi-stage vacuum pump sharing drive shaft - Google Patents

Abstract

The utility model discloses a multistage vacuum pump of sharing drive shaft, establish ties or parallel connection forms multistage vacuum drive chamber including a plurality of vacuum drive chambeies, sets up an at least rotor in every independent vacuum drive intracavity, and the direct atmosphere of entry in first order vacuum drive chamber wherein has two vacuum drive chambeies at least to drive with a sharing drive shaft, and wherein this sharing drive shaft includes two at least separation drive shafts. The vacuum pump composed of the plurality of vacuum driving cavities can be a coaxial multi-stage pump, such as a multi-stage roots pump, driven by a single motor, or at least one non-coaxial vacuum driving cavity is driven by an independent or shared driving motor. Due to the adoption of the sectional type driving shaft, expansion and contraction of heat and cold of a pair of impellers and the shaft in each vacuum cavity cannot be transmitted to the other vacuum cavity adjacent to the axial direction, and the influence of expansion and contraction of heat and cold of the adjacent cavity in the axial direction cannot be caused.

Description

Multi-stage vacuum pump sharing drive shaft

Technical Field

The utility model relates to a vacuum pump field especially relates to a multistage vacuum pump including at least a shared drive shaft.

Background

In the field of vacuum technology, the equipments capable of directly exhausting air and forming vacuum mainly include liquid ring pumps, direct exhaust air-cooled roots vacuum pumps, ejector pumps (including steam ejector pumps, water ejector pumps), slide valve pumps, reciprocating pumps, rotary vane vacuum pumps (divided into oil-type rotary vane vacuum pumps and oil-free dry rotary vane vacuum pumps), screw vacuum pumps, claw vacuum pumps, multistage roots vacuum pumps, scroll vacuum pumps, etc. The common roots vacuum pump can form higher vacuum, but the exhaust pressure cannot reach the pressure of direct exhaust atmosphere, and the vacuum pump is required to be equipped as a backing pump to ensure that the pump can normally and safely operate. The roots type air cooling pump can directly discharge air, but the efficiency is reduced, the power consumption and the noise are large because the exhausted air must be led back to the pump cavity after being cooled, and the maximum working vacuum degree is only about 2 ten thousand pascals.

In order to solve the problems related to the vacuum pump in the prior art, the inventor provides a multi-drive-cavity non-coaxial vacuum pump which comprises a plurality of independent vacuum drive cavities, wherein the plurality of vacuum drive cavities are connected in series to form a multi-stage vacuum drive cavity, a pair of independent rotors are arranged in each independent vacuum drive cavity, the multi-drive-cavity non-coaxial vacuum pump is characterized in that the air flow direction of the plurality of vacuum drive cavities and a rotor drive shaft form a vertical or large included angle of 30 ~ 90 degrees, an inlet of a first-stage vacuum drive cavity is communicated with the atmosphere, all or part of the plurality of vacuum drive cavities are not coaxial, all the non-coaxial vacuum cavities are driven by adopting independent drive motors, the plurality of vacuum drive cavities are stacked in sequence from top to bottom to form the multi-stage vacuum drive cavities connected in series, a suction inlet of a lower-stage vacuum drive cavity is connected with an upper-stage vacuum drive cavity, and water outlets are respectively arranged at two sides of each vacuum drive cavity, and a water layer is arranged below each vacuum drive cavity.

However, although the vacuum pump in the above prior art can solve some problems in terms of environmental protection, when the multi-stage vacuum driving chambers use a common driving shaft, the impeller/shaft in each vacuum chamber may expand or contract due to the expansion and contraction of the adjacent vacuum chambers.

Therefore, the present invention provides a multi-stage vacuum pump to improve the above problems, and to eliminate the axial influence of the driving shaft of the vacuum driving chamber caused by thermal expansion and contraction on the driving shaft of another connected vacuum driving chamber.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a multistage vacuum pump including an at least sharing drive shaft, this multistage vacuum pump is a section can bear certain dust, certain corruption, be convenient for maintain, the dry vacuum pump that the extraction volume is big.

According to the preferred embodiment of the scheme, the plurality of vacuum driving cavities are sequentially stacked into the multistage vacuum driving cavities connected in series from top to bottom, the suction inlet of the lower vacuum driving cavity is connected with the exhaust outlet of the upper vacuum driving cavity, the suction inlet of each vacuum driving cavity is located above, the exhaust outlet is located below or on the side, and each vacuum driving cavity is driven by the independent motor.

In order to achieve the above object, the present invention provides a multi-stage vacuum pump including at least one common driving shaft, comprising a plurality of independent vacuum driving chambers, wherein the plurality of vacuum driving chambers are connected in series or in parallel to form a multi-stage vacuum driving chamber, at least one rotor is arranged in each independent vacuum driving chamber, and an inlet of a first stage vacuum driving chamber is directly connected to atmosphere or a front stage device; wherein at least two vacuum drive chambers are driven by a common drive shaft, wherein the common drive shaft comprises at least two separate drive shafts.

Preferably, the at least two vacuum driving chambers driven by the common driving shaft are a first vacuum driving chamber and a second vacuum driving chamber respectively, the common driving shaft includes a first separation driving shaft and a second separation driving shaft, the first separation driving shaft is located in the first vacuum driving chamber, the second separation driving shaft is located in the second vacuum driving chamber, wherein the first separation driving shaft and the second separation driving shaft are connected by a first connecting member, and the first separation driving shaft and the second separation driving shaft are spaced apart by a distance.

It is further preferred that the common drive shaft further comprises a third split drive shaft, the first split drive shaft being located on one side of the second split drive shaft and the third split drive shaft being located on the other side of the second split drive shaft, the second split drive shaft being connected to the third split drive shaft by a second connection.

It is further preferred that the third separating drive shaft is connected to the motor shaft of a drive motor.

Further preferably, the first vacuum driving chamber further comprises a first driven shaft, and the first driven shaft is connected with a first gear; wherein the first split drive shaft is connected with a second gear; the first gear engages the second gear.

Further preferably, the second vacuum driving chamber further comprises a second driven shaft, and the second driven shaft is connected with a third gear; wherein the second split drive shaft is connected with a fourth gear; the third gear engages the fourth gear.

Preferably, the vacuum pump comprising a plurality of the vacuum driving chambers is a coaxial multi-stage pump.

Further preferably, the vacuum pump is a multistage roots pump or a screw vacuum pump or a multistage claw vacuum pump.

Preferably, the vacuum pump is a non-coaxial multi-stage vacuum pump having at least one coaxial line.

In practical applications, the multi-stage vacuum chambers that may be selected according to the present invention may be 2, 3, 4, 5, 6 or even more stages, depending on the actual requirements. The driving motors may share power through a transmission device, or the motors may correspond to the vacuum chambers in number one by one.

According to the utility model discloses a preferred embodiment, the vacuum drive chamber adopts the lobe pump design, and the vacuum drive chamber can adopt and decide frequently or variable frequency drive motor drive, and its rotor drive shaft is connected with deciding frequently or variable frequency drive motor promptly.

Drawings

Fig. 1 is a schematic diagram of the present invention.

Fig. 2 is a schematic structural view of an embodiment of the present invention, which is not completely coaxial.

Fig. 2-1 is another embodiment of fig. 2.

FIG. 3 is a cross-sectional view of a coaxial vacuum drive chamber.

Fig. 4 is a schematic structural view of another partially coaxial embodiment of the present invention.

Fig. 5 is a cross-sectional view of fig. 4.

Fig. 5-1 is another embodiment of fig. 5.

Detailed Description

The utility model discloses a multistage vacuum pump including an at least sharing drive shaft also adopts multistage compression, and the principle is by the independent vacuum drive chamber of a plurality of (decide to adopt how many vacuum drive chamber modules according to actual need) in this vacuum pump intracavity, and each independent real empty room all has a pair of independent roots's rotor. Referring to fig. 1, in this embodiment, four vacuum driving chambers are included, namely a 1-stage vacuum driving chamber 1, a 2-stage vacuum driving chamber 2, a 3-stage vacuum driving chamber 3 and a 4-stage vacuum driving chamber 4, and the principle is as follows: when the non-coaxial vacuum pump suction inlet 5 of many drive chamber bodies reaches 1 mbar's limit vacuum, the gas vent is 20mbar, the compression ratio is approximately 20 times, the gas vent in 2 grades of vacuum drive chamber is 120mbar, the compression ratio is approximately about 6 times, the gas vent in 3 grades of vacuum drive chamber is 360mbar, the compression ratio is approximately about 3 times, the gas vent 6 in 4 grades of vacuum drive chamber is 1080mbar, the compression ratio is also approximately about 3 times, in the actual project, then according to different demands, design independent pump chamber, realize different compression ratios.

When the inlet is loaded, the vacuum level at the suction port is below 1mbar and the compression ratio of each adjacent vacuum driven chamber is correspondingly reduced (the overall compression ratio is reduced).

The compression ratio is mainly based on the heat and the consumed power that each vacuum driving cavity can bear, and the higher the vacuum environment, the higher the compression ratio is, but the mass flow of the compressed gas is lower (under the same volume), the accumulated heat is lower (mainly affected by heat dissipation), and the consumed power is also lower, so the compression ratio can be larger at the moment. In a rough vacuum environment, the mass flow rate of the compressed gas is high (under the same volume), the accumulated heat is large (the heat dissipation effect is small), and the consumed power is large, so that the compression ratio is required to be as small as possible.

In view of the schematic diagram of the apparatus, the rotation direction of the rotor of the stage 1 vacuum driving chamber of the variable speed variable capacity dry vacuum pump of this embodiment is the same as the rotation direction of the rotor of the stage 3 vacuum driving chamber (the driving shafts of the stage 1 and the stage 3 vacuum driving chambers are the same axis), but is the same as the rotation direction of the rotor of the stage 2 vacuum driving chamber and the stage 4 vacuum driving chamber (the driving shafts of the stage 2 and the stage 4 vacuum driving chambers are the same axis), so the driving shafts of the four vacuum driving chambers are not on the same axis, which is completely different from the conventional multistage roots vacuum pump, claw vacuum pump, and screw vacuum pump.

In order to further optimize the operation effect, the utility model discloses still provide the frequency conversion drive mode of individual or whole vacuum drive cavity, through frequency conversion control at any time along with concrete requirements such as time, pressure, pumping speed, temperature, give the optimization of full pump operation to including but not limited to compression ratio, motor and heat management etc. every aspect. These characteristics are not realized by a coaxial multistage roots pump, a screw pump and a claw pump.

What has been described above is the technical principle of the present invention, i.e. the continuously variable compression non-coaxial or incomplete coaxial variable-speed variable-capacity dry vacuum pump with multiple driving cavities.

FIG. 2 is an external view of a second embodiment of a multi-drive chamber non-coaxial vacuum pump, and FIG. 3 is a cross-sectional view of FIG. 2. In the figure: 1 is 1 level vacuum drive chamber, 3 is 3 level vacuum drive chambers, 5 is the vacuum pump sunction inlet, 6 is the vacuum pump discharge port, 7 is the median septum double-ended face mechanical seal, 8 is the gear, 9 is the bearing, 10 is the drive end cover, 11 is first drive shaft, 12 is the second drive shaft.

In this embodiment, the vacuum driving chamber includes four independently disposed vacuum driving chambers, which are respectively a 1-stage vacuum driving chamber, a 2-stage vacuum driving chamber, a 3-stage vacuum driving chamber and a 4-stage vacuum driving chamber connected in series in sequence, wherein the 1-stage vacuum driving chamber and the 3-stage vacuum driving chamber share one motor drive (as can be seen in the figure, the 1-stage vacuum driving chamber and the 3-stage vacuum driving chamber share a first driving shaft 11 and are connected with the motor through a gear 8), the 2-stage vacuum driving chamber and the 4-stage vacuum driving chamber share a second driving shaft 12, and are driven by another motor, the rotation directions of the rotors of the 1-stage vacuum driving chamber 1 and the 3-stage vacuum driving chamber 3 are the same, but are exactly opposite to the rotation directions of the rotors of the 2-stage vacuum driving chamber and the 4-stage vacuum driving chamber, and the exhaust port of the 1-stage vacuum driving chamber and the suction port of the 2-stage vacuum driving chamber are disposed in the same direction, i, the exhaust port of the 2-stage vacuum driving cavity and the suction inlet of the 3-stage vacuum driving cavity are arranged in the same direction, and the exhaust port of the 3-stage vacuum driving cavity and the suction inlet of the 4-stage vacuum driving cavity are arranged in the same direction.

The driving shafts of the four vacuum driving chambers are not on the same shaft in the embodiment, which is completely different from the existing multi-stage roots vacuum pump, claw vacuum pump and screw vacuum pump.

In another embodiment of fig. 2-1, the stage 1 vacuum drive chamber 1 and the stage 3 vacuum drive chamber 3 are driven by a common drive shaft 13. The common drive shaft 13 is formed by at least two separate drive shafts, in this case three separate drive shafts 131, 132, 133 forming the common drive shaft 13. Wherein the first separation driving shaft 131 is located in the stage 1 vacuum driving chamber 1; the second split drive shaft 132 is located within the 3-stage vacuum drive chamber 3. The first separating driving shaft 131 is located at one side of the second separating driving shaft 132, and the third separating driving shaft 133 is located at the other side of the second separating driving shaft 132. Wherein the first split driving shaft 131 is connected to the second split driving shaft 132 by a first connecting member 136, and the first split driving shaft 131 is spaced apart from the second split driving shaft 132; and the second separating driving shaft 132 is connected with the third separating driving shaft 133 by a second connecting member 137.

In the example of this embodiment, the dual motors are adopted, and the rotation speeds of the two driving shafts are different at different rotation speeds, the rotation speeds of the rotors in the 1-stage vacuum driving cavity, the 3-stage vacuum driving cavity and the 2-stage vacuum driving cavity are different, and the rotation speeds of the rotors in the 4-stage vacuum driving cavity are opposite, so that the shortest distance between the air flows passing through the 4 vacuum driving cavities is realized, and no dead angle exists. This is a substantial difference from the existing multi-stage roots vacuum pumps and claw vacuum pumps. The variable compression ratio in the vacuum driving cavity can be realized due to the adjustable rotating speed, so that the multi-driving-cavity non-coaxial or incomplete-coaxial vacuum pump has the characteristic that the vacuum degree and the suction amount of a pump suction inlet can be adjusted through the rotating speed, which is not possessed by any other vacuum pump. The principle is that the original compression ratio of the vacuum driving cavity is changed through different speeds, so that the vacuum degree and the suction amount of the suction port of the 1-stage vacuum driving cavity are influenced. The actual requirements of the customers can be really realized.

The existing multi-stage roots pump adopts a coaxial design, namely impellers of the multi-stage roots pump are arranged on the same shaft, so that gas exhausted from a certain stage of exhaust port needs to be wound to the other side of the stage of exhaust port to enter the gas inlet of the next stage. Different from multistage lobe pump, the utility model discloses the vacuum drive impeller shaft of well many drive chambeies is non-coaxial, and the impeller turns to and can arrange in a flexible way, therefore a benefit of non-coaxial vacuum cavity drive makes the tolerance can follow the most straight, the principle of shortest path flow is nimble arranges, and because of unlike multistage lobe pump, the combustion gas must be wound back to the other one side of this level gas vent and just can enter into the income gas port of next stage, make at gaseous loss energy in long-distance flow, and make the dust wherein subside that slows down more easily, the jam passageway.

Similarly, the advantage that the gas can flow smoothly along the gravity direction and the air quantity direction and pass through the large-sized exhaust port, so that the dust wrapped in the gas can be discharged easily is remarkably superior to the advantage that the gas in the screw pump moves horizontally in the closed rectangular cavity, and the wrapped dust can not be discharged from the small exhaust port at the single side of the tail end by virtue of gravity and air flow.

And, compare multistage roots pump again, because coaxial design for the progression can not too much, the size can not too big, otherwise the axle can become very long, mechanical stability descends. The utility model discloses then do not have this restriction.

Fig. 4 and 5 are another arrangement of the present embodiment. In the figure: the vacuum pump comprises a vacuum driving cavity 1, a vacuum driving cavity 2, a vacuum pump suction inlet 5, a vacuum pump discharge outlet 6, a middle partition plate double-end-face mechanical seal 7, a gear 8, a shared driving shaft 13, a first driven shaft 14 and a second driven shaft 15. The vacuum driving cavity of the present embodiment adopts a staggered arrangement form, the rotation direction of the rotor of the 1-stage vacuum driving cavity 1 is opposite to the rotor direction of the 2-stage vacuum driving cavity 2 (the driving shafts of the 1-stage vacuum driving cavity 1 and the 2-stage vacuum driving cavity 2 are the same common driving shaft 13, but the driven shafts thereof are staggered, so that the rotation directions of the two are opposite), the rotation direction of the rotor of the 3-stage vacuum driving cavity is also opposite to the rotation direction of the rotor of the 4-stage vacuum driving cavity (the driving shafts of the 3-stage vacuum driving cavity and the 4-stage vacuum driving cavity are the same shaft, but the driven shafts thereof are staggered, so that the rotation directions of the two are opposite), similarly, the exhaust port of the 1-stage vacuum driving cavity and the suction port of the 2-, namely, the exhaust port of the 2-stage vacuum driving cavity and the suction port of the 3-stage vacuum driving cavity are arranged in the same direction, and the exhaust port of the 3-stage vacuum driving cavity and the suction port of the 4-stage vacuum driving cavity are arranged in the same direction.

It should be noted that, in the above example, we refer to the 4-stage driving cavity, the 1 and 3 driving cavities turn in the same direction, and the 2 and 4 drivers turn in the same direction in opposite directions, and a two-shaft differential motor is adopted, which is just a specific arrangement of the application principle of the present invention. In fact, according to the pump body that the customer applied the requirement to the vacuum degree and the requirement of each work vacuum section, the utility model discloses a concrete form of arranging can be the vacuum drive chamber progression that the figure is different, respectively specific vacuum drive chamber direction of rotation and different figure, different forms's motor.

In another embodiment of fig. 5-1, in which the common drive shaft 13 is constituted by at least two separate drive shafts, in this embodiment the common drive shaft 13 is constituted by three separate drive shafts 131, 132, 133. Wherein the first separation driving shaft 131 is located in the stage 1 vacuum driving chamber 1; the second split drive shaft 132 is located within the 2-stage vacuum drive chamber 2. The first separating driving shaft 131 is located at one side of the second separating driving shaft 132, and the third separating driving shaft 133 is located at the other side of the second separating driving shaft 132. Wherein the first split driving shaft 131 is connected to the second split driving shaft 132 by a first connecting member 136, and the first split driving shaft 131 is spaced apart from the second split driving shaft 132; and the second separating driving shaft 132 is connected with the third separating driving shaft 133 by a second connecting member 137.

Wherein the rear end 1311 of the first separating driving shaft 131, the rear end 141 of the first driven shaft 14, and the rear end 151 of the second driven shaft 15 have the same pattern in a uniform manner, so as to facilitate modular production.

As shown in fig. 5-1, the 1-stage vacuum driving chamber 1 includes the first driven shaft 14 therein, and the first driven shaft 14 is connected to a first gear 81; wherein the first split drive shaft 131 is connected to a second gear 82; the first gear 81 engages the second gear 82.

Wherein the 2-stage vacuum driving chamber 2 comprises the second driven shaft 15, and the second driven shaft 15 is connected with a third gear 83; wherein the second split drive shaft 132 is connected to a fourth gear 84; the third gear 83 engages the fourth gear 84.

The purpose of the above arrangement is to avoid the mutual interference of each vacuum driving chamber, so that the common driving shaft 13 is "disconnected" into at least two separate driving shafts, which can still transmit torque, and can eliminate the axial influence of the separate driving shaft of one vacuum driving chamber on the separate driving shaft of another connected vacuum driving chamber caused by thermal expansion and cold contraction, thereby ensuring that the impeller and the separate driving shaft in each vacuum driving chamber are not influenced by the expansion or contraction of the impeller and the separate driving shaft caused by thermal expansion and cold contraction of the adjacent vacuum driving chambers. This is advantageous for enlarging the multi-stage roots pump.

The utility model discloses also can adopt the principle the same, with speed at present each grade of each model lobe pump plus inverter motor or gear box control, including but not limited to, series connection-full open type series or rotation series, longitudinal arrangement, ladder are arranged (use the side gas vent to turn to) or the level is arranged, or parallelly connected, or mix the parallelly connected integrated multistage vacuum pump including at least a common drive shaft of cluster, wherein every lobe pump is a drive chamber.

The utility model discloses a vacuum principle of the non-coaxial or incomplete coaxial variable speed varactor dry vacuum pump of many drive cavitys accords with the hydrodynamics principle with current multistage roots vacuum pump, claw vacuum pump, screw vacuum pump, utilizes the mode of becoming the volume compression promptly, compresses the gas of vacuum sunction inlet step by step, finally surpasss atmospheric pressure and discharges. However, in addition to the various features of the present invention described above, there are different points or more advantages compared to the existing dry pumps as follows: compared with the existing multi-stage roots pump, the existing multi-stage roots pump adopts a coaxial integrated design, so that the compression ratio among stages, the position relation among vacuum cavities and the airflow direction are all completely fixed forever. Thus, the compression ratio between the pump chambers of the respective stages cannot be adjusted in any operating pressure range. Because the compression ratio of the Roots vacuum pump under the rough vacuum condition cannot be too large, otherwise, the pump is blocked due to too large temperature rise of the pump; and can be large under high vacuum, low compression ratios can reduce efficiency. Therefore, a multistage roots pump in which the position and the rotation speed of the vacuum chamber are coaxially fixed cannot maintain optimal performance in each vacuum degree range. Because the utility model discloses a different driving motor drives of non-coaxial use, consequently can make each vacuum drive chamber with different rotational speeds at any time (or when the design) according to needs nimble adjustment rotational speed, and then change the interstage compression ratio, make the pump can compromise safety and efficiency, it is controllable to reach the optimization, it is more even to make the pressure differential of each grade share with the heat share, but coaxial multistage lobe pump then only shares evenly in the initial stage, and will press most burden to last one-level when arriving the high vacuum.

Compared to dry plunger pumps and direct atmospheric air-cooled pumps: in the positive displacement dry vacuum pump, the process gas is continuously compressed and exhausted to reach a high vacuum degree, and like a reciprocating pump and a gas-cooled roots vacuum pump which directly exhausts the atmosphere, part of the process gas circulates in a pump cavity or a system and is repeatedly compressed, so that a suction port of the vacuum pump is influenced by the residual gas, and when a piston of the reciprocating pump returns or the gas returns after the gas-cooled pump is cooled, the gas expands to occupy the working space of the positive displacement pump, so that the gas cannot reach the high vacuum degree, extra power is consumed, and extra mechanical materials are wasted. The utility model provides a many drive cavity non-coaxial or incomplete coaxial variable speed variable capacity dry vacuum pump though have 4 or a plurality of independent and mutual inclosed vacuum drive chamber, all process gas all are direct discharges after the continuous compression, consequently the efficiency is the highest.

When the multi-stage vacuum pump is coaxial with the driving motor, the connection between the vacuum cavity and the motor shaft can also adopt a sectional connecting key connecting shaft.

It is obvious that the described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Claims (9)

1. A multi-stage vacuum pump with a common driving shaft comprises a plurality of independent vacuum driving cavities, wherein the vacuum driving cavities are connected in series or in parallel to form the multi-stage vacuum driving cavities, and each independent vacuum driving cavity is internally provided with at least one rotor;

wherein at least two vacuum drive chambers are driven by a common drive shaft, wherein the common drive shaft comprises at least two separate drive shafts.

2. The multi-stage vacuum pump of claim 1, wherein the at least two vacuum drive chambers driven by the common drive shaft are a first vacuum drive chamber and a second vacuum drive chamber, respectively, the common drive shaft comprising a first split drive shaft and a second split drive shaft, the first split drive shaft being located in the first vacuum drive chamber and the second split drive shaft being located in the second vacuum drive chamber, wherein the first split drive shaft and the second split drive shaft are connected by a first connection member and the first split drive shaft is spaced apart from the second split drive shaft.

3. A common drive shaft multi-stage vacuum pump according to claim 2, wherein the common drive shaft further comprises a third split drive shaft, the first split drive shaft being located on one side of the second split drive shaft and the third split drive shaft being located on the other side of the second split drive shaft, the second split drive shaft and the third split drive shaft being connected by a second connection.

4. A multi-stage vacuum pump with a common drive shaft as in claim 3, wherein the third split drive shaft is connected to a motor shaft of a drive motor.

5. The multi-stage vacuum pump with a common drive shaft of claim 2, further comprising a first driven shaft in the first vacuum drive chamber, the first driven shaft being connected to a first gear; wherein the first split drive shaft is connected with a second gear; the first gear engages the second gear.

6. A multi-stage vacuum pump having a common drive shaft as in claim 2, further comprising a second driven shaft within the second vacuum drive chamber, the second driven shaft being coupled to a third gear; wherein the second split drive shaft is connected with a fourth gear; the third gear engages the fourth gear.

7. A multi-stage vacuum pump with a common drive shaft as in claim 1, wherein the vacuum pump comprising a plurality of vacuum drive chambers is a coaxial multi-stage pump.

8. A multi-stage vacuum pump sharing a drive shaft as claimed in claim 7, wherein the vacuum pump is a multi-stage roots pump or a screw vacuum pump or a multi-stage claw vacuum pump.

9. A multi-stage vacuum pump having a common drive shaft as in claim 1, wherein the vacuum pump is a non-coaxial multi-stage vacuum pump having at least one coaxial shaft.