JPH11159493A - Molecular drag compressor having finned rotor structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously achieve a high exhaust pressure and a high pumping speed. SOLUTION: A rotor disk 100 includes fins 120, 122, 124, 126 arranged inside a passage in such a manner as to be uniformly fixed over the circumferential edge of the rotor disk 100 and spaced apart from each other, so that transverse sub passages 130, 132, 134 are defined to be connected to an inlet and an outlet which are shut out from each other via baffles. The baffles are complementarily arranged in such a manner as to substantially shut out the transverse sub passages 130, 132, 134, and are adapted to increase an exhaust pressure of a molecular drag vacuum pumping stage when the rotor disk 100 is rotated. In another embodiment, a stator includes fins spaced apart from each other, and a rotor includes baffles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molecular drag compressor used for exhausting a closed chamber, and more particularly to a molecular drag compressor having a finned rotor or a finned stator structure for improving its performance.

[0002]

2. Description of the Prior Art A conventional turbomolecular pump includes a housing having an inlet port, a chamber having a plurality of pumping stages therein in an axial direction, and an outlet port. Each pumping stage includes a stator having inclined blades and a rotor having inclined blades. The blades of the rotor are rotated at high speed to pump gas between the inlet and outlet ports.

[0003] Vacuum pumping systems using axial pumping stages in combination with other types of pumping stages are known in the prior art. In one prior art configuration, one or more axial pumping stages are replaced by a high speed rotating disk that functions like a molecular drag stage. This arrangement is disclosed in U.S. Pat. No. 5,238,362, assigned to the assignee of the present invention (Casar).
o et al., issued August 24, 1993). Varian Associates, Inc. vacuum pump (model number 969-9007) that includes an axial turbo molecular compressor and a molecular drag compressor in a common housing
Are sold. Vacuum pumps using molecular drag disks and vortex impellers are disclosed in German Patent No. 3,919,52.
No. 9 (issued January 18, 1990).

[0004] A molecular drag compressor includes a rotating disk and a stator. The stator forms a tangential flow (or cross flow) flow path and an inlet and an outlet of the cross flow flow path. As is known in the prior art, the momentum of the rotating disk is transferred to gas molecules in the cross flow channel, which directs the molecules toward the outlet. The rotating disk and stator of the molecular drag compressor are
They are separated by a small gap, typically on the order of about 0.005 inches, which is selected to minimize leakage through this gap and to allow free rotation of the disk.

[0005] "Vacuum Science and
Technology, Pioneers of
the 20th Century (pp. 47-48,
P. A. Redhead Editor, AIP Pr
ess, 1994), a molecular pump of W. Gaede, in which multiple stages are arranged in series and the rotor is finned.

[0006]

Prior art vacuum pumps, including axial turbo molecular compressors and molecular drag compressors, perform almost satisfactorily under a variety of conditions. However, one drawback of such pumps is that there is a trade-off between pumping speed (volume of gas pumped per unit time) and exhaust pressure. That is, designing the pump to be optimal for high pumping speeds reduces the achievable exhaust pressure, and conversely reduces pumping speed for pump designs that optimize exhaust pressure. In the molecular drag stage, the pumping speed can be increased by increasing the cross-sectional area of the cross flow channel. However, this will increase the backflow through the cross flow channel, thereby reducing the achievable exhaust pressure. It is desirable to be able to evacuate to atmospheric pressure, which eliminates the need for a roughing pump.

[0007] Accordingly, it is desirable to provide a structure of a molecular compressor that simultaneously achieves high exhaust pressure and high pumping speed.

[0008]

SUMMARY OF THE INVENTION A molecular vacuum pumping stage according to a first aspect of the present invention comprises a stationary element and a rotating element, wherein the elements permit rotation of the rotating element with respect to the stationary element. It is arranged in cooperation. The stationary and rotating elements form a flow path having an inlet and an outlet.
One of the fixed and rotating elements includes fins that are uniformly fixed around the periphery and are spaced apart from each other and arranged in the flow path. The fins define one or more crossflow sub-channels, each of which communicates with an inlet and an outlet of the channel. The other of the stationary and rotating elements includes baffles arranged in the flow path. The baffles and fins have complementary geometries such that the baffle substantially blocks the crossflow sub-channel. As the rotating element rotates relative to the stationary element, gas is pumped from the inlet of the flow path through the cross flow sub-flow path to the outlet of the flow path.

In a first configuration, the fins are mounted on a rotating element and the baffles are mounted on a stationary element. In a second configuration, the fins are attached to a stationary element and the baffles are attached to a rotating element. In each case, rotation of the rotating element causes the fin to move with respect to the baffle.

A molecular vacuum pumping stage according to another aspect of the present invention comprises a rotor disk connected to a drive shaft that rotates about an axis, a stator arranged around the rotor disk, and a baffle. The stator defines a flow path having an inlet and an outlet, and the rotor disk includes two or more fins that are uniformly fixed around the periphery thereof and are spaced apart from each other and arranged in the flow path. The fins define one or more crossflow sub-channels, each of which communicates with an inlet and an outlet of the channel. The baffles and fins have complementary geometries such that the baffle substantially blocks the crossflow sub-channel. As the rotor disk rotates relative to the stator, gas is pumped from the inlet of the flow path through the cross flow sub-flow path to the outlet of the flow path.

In a first embodiment, the fins project radially within the cavity. In a second embodiment, the fins
Protrudes axially in the cavity. One or more crossflow sub-channels have a total cross-sectional area that determines the pumping speed of the molecular drag compressor.

An integrated high vacuum pump according to another aspect of the present invention comprises an external pump housing having an axis, an axial turbo-molecular compressor arranged in the housing, and a molecular drag compressor arranged in the housing. Consists of Each of the turbo molecular compressor and the molecular drag compressor has a rotating part connected to a single drive shaft arranged coaxially with the housing axis. The molecular drag compressor includes at least one molecular drag stage having a finned rotor or finned stator configuration, as described above.

[0013]

DETAILED DESCRIPTION OF THE INVENTION An integral high vacuum pump suitable for incorporation of the present invention is shown in FIG. The housing 10 has an inner chamber 12 having an inlet port 14 and an outlet port 16.
Is formed. The housing 10 includes a vacuum flange 18 for sealing an inlet port 14 connected to a vacuum chamber to be evacuated (not shown). Exit port 1
6 is typically connected to a roughing pump (not shown). If the illustrated vacuum pump is capable of evacuating to atmospheric pressure, a roughing pump is not required. An axial turbo molecular compressor 20 and a molecular drag compressor 22 are arranged inside the housing 10. Typically, the axial turbomolecular compressor 20 includes several stages of axial turbomolecular stages, and the molecular drag compressor 22 includes several stages of molecular drag stages. Each stage of the axial turbo-molecular compressor 20 includes a rotor 24 and a stator 26. Each of the rotor and the stator
With inclined blades known from the prior art. Each stage of the molecular drag compressor 22 includes a rotor disk 30 and a stator 3
2 is included. The molecular drag compressor 22 will be described later in detail. The rotor 24 of each turbo molecular stage and the rotor 30 of each molecular drag stage are mounted on a drive shaft 34. The drive shaft is rotated at high speed by a motor provided in the motor housing 38.

A first embodiment of a molecular drag stage suitable for use in the molecular drag compressor 22 is shown in FIGS. The molecular drag stage includes a rotor disk 100 and a stator 102.
And mounted in a housing as shown in FIG. 1 as described above. The stator forms a flow path 104, and the rotor disk 100 rotates in the flow path 104. As is known in the prior art, the stator 102
It can be manufactured in an assembled manner. For example, the upper stator portion may be located proximate the upper surface of rotor disk 100 and the lower stator portion may be located proximate the lower surface of rotor disk 100. These stator portions are fixed together to form a single stator body. Disk 100
Attached to shaft 108 and rotates about axis 110.

In accordance with the present invention, the rotor disk 100 includes two or more fins 12 that are uniformly secured around the periphery thereof and that are spaced apart from each other and arranged in the flow path 104.
0, 122, 124 and 126 are provided. In the embodiment of FIGS. 2-4, fins 120, 122, 124, 126 project radially about axis 110 into flow path 104. These fins form one or more transverse sub-channels. In the embodiment of FIGS. 2-4, the fins 120, 122 define a crossflow sub-channel 130, the fins 122, 124 define a crossflow sub-channel 132, and the fins 124, 126 define a crossflow sub-channel 134. ing. In the embodiment of FIGS. 2 to 4, the fins 120, 122, 124, 126 protrude a fixed distance laterally from the periphery of the rotor disk 100. That is, the fins 120, 122, 124,
126 is formed in the periphery of the rotor disk 100 in an annular shape. In the cylindrical coordinate system defined by axis 110, fins 120, 122, 124, 126 have r-θ
Lies on a plane.

A small space is provided between the rotor disk 100 and the stator 102 in addition to the cross flow sub-channels 130, 132, and 134. In particular, the upper surface 12 of the fin 120
0a and the stator 102, the lower surface 12 of the fin 126
A small clearance space is provided between 6 a and the stator 102 and between the lower surface 126 a of the fin 126. Similarly, the fins 120, 122, 124, 1
A small clearance space is also provided between the outer peripheral edge of 26 and the inner peripheral wall 102a of the stator 102. The clearance space is typically a few thousandths of an inch and is selected to allow the rotor disk 100 to rotate freely and to limit gas leakage between the rotor disk 100 and the stator 102.

The fins 120, 122, 124, 126,
And the size of the space between the fins is selected based on the desired performance of the molecular drag stage. Typically,
Fins 120, 122, 124, 126 are 1-3 cm
And has a thickness in the order of 0.5 to 1.0 mm. 1-2 mm between fins
About a degree apart. The size of these fins is selected to provide structural rigidity during high speed rotation. The size of the cross flow sub-channels 130, 132, 134 is selected to provide the desired pumping speed, as described below. The rotor disk 100 has a diameter of about 10 to 20 cm. Here, the sizes described above are merely examples, and do not limit the scope of the present invention.

The stator 102 includes a baffle 140 that blocks each of the laterally located sub-flow passages. Fins 120,
122, 124, 126 and baffle 140 have complementary geometries such that the baffle substantially blocks each crossflow channel. In particular, the baffle 140 includes fingers 142 projecting into the crossflow sub-channel 130, fingers 144 projecting into the crossflow sub-channel 132, and fingers 146 projecting into the crossflow sub-channel 134.
These fingers 142, 144, 146 provide fins 120, 122, 12 so as to provide a small clearance space between rotor disk 100 and stator 102.
4 and 126. As shown in FIG. 2, the stator 102 has an inlet 150 into each crossflow sub-channel.
And an outlet 152 from each transverse sub-channel. Typically, inlet 150 and outlet 152 are provided with baffle 140
It is arranged on the opposite side.

In the molecular drag stage of the present invention, the inlet and outlet are arranged in different directions. Examples of axial and radial inlet and outlet arrangements are shown in FIGS. 5 and 6, respectively. 2 to 6, similar components are denoted by the same reference numerals. FIG. 5 shows the entrance 150a in the axial direction.
This inlet is typically provided at one location on the periphery of the molecular drag stage. The inlet 150 a receives gas in the axial direction about the axis 110 near the periphery of the rotor 100. The inlet 150a is connected to the cross flow sub-channels 130, 132, 13
4 includes a passage 160 for distributing gas. FIG. 6 shows a radial entrance 150b. The entrance 150b
The gas is received radially with respect to axis 110. The gas is passed through the passage 162 to the transverse sub-channels 130, 132,
134. A similar configuration may be used at the exit of the molecular drag stage. For example, the molecular drag stage is
It may have an axial inlet on one side and an axial outlet on the other side. Such a configuration is particularly useful for vacuum pumps having one or more stages. Here, various inlets and outlets arranged in different directions may be implemented within the scope of the present invention. However, it is important to maximize the conductance of the gas from the previous stage to all fins without reducing pumping speed. If the axial gas inlet is in the middle of the fin 120, the speed of the stage will be significantly reduced. Also, the molecular drag stage may have one or more inlets and one or more outlets, as shown below in FIGS.

In operation, gas is received through inlet 150 from the previous stage or other source. The stage immediately before this is a molecular drag stage, an axial turbo molecular stage,
Or any other available vacuum pumping stage. The gas enters the transverse flow sub-channels 130, 132, 134 and is pumped around the periphery of these transverse flow sub-channels by the molecular drag generated by the rotation of the disk 100. The gas is then sent through outlet 152 to the next stage or outlet port of the pump. Thus, FIGS.
The above described molecular drag stage differs in important points from prior art molecular drag pumps. As shown in FIG. 3, each of the cross flow sub-channels 130, 132, 134 contacts three surfaces of the rotor disk 100. For example, the cross flow sub-channel 130 contacts the lower surface of the fin 120 of the rotor disk 100, the upper surface of the fin 122, and the inner end surface 130a thereof. In contrast, the cross-flow channels of prior art molecular drag stages typically contact only one of the planes of rotation. That is, compared to one moving surface of the conventional molecular drag stage, the molecular drag stage of FIGS.
Gas molecules in the cross flow sub-channel impinge on three moving surfaces of the rotor disk. Since the actuation of the molecular drag stage is performed by transferring the momentum of the rotating disk to gas molecules, the molecular drag stage of the present invention, in which the moving area is large compared to the fixed area, increases the gas pumping efficiency. Also, the exhaust pressure is substantially increased as compared to prior art molecular drag pumps. The exhaust pressure of the molecular drag pump according to the invention is lower than that of the prior art molecular drag pump.
It increased about two-fold.

Each of the cross flow sub-channels 130, 132, 134 has an inlet and an outlet, the inlet and outlet being juxtaposed.
The fins 120, 122, 124, 126 divide the flow path 104 into transverse flow sub-flow paths 130, 132, 134, which connect between the inlet and outlet of the side-by-side molecular drag stage. The overall pumping speed of the molecular drag stage is proportional to the total cross-sectional area of the cross flow sub-channels 130, 132, 134. By increasing the number of cross flow sub-channels and / or their cross-sectional area, the pumping speed may be increased.

A performance comparison test was conducted between the finned rotor structure of the present invention and the molecular drag stage structure of the prior art. The test was performed by arranging a rotor disk comprising three fins with a radial depth of 19.5 mm, a thickness of 1.6 mm and a space of 2.0 mm between the fins on a molecular drag stage. Was. Molecular drag compressors have particularly been considered as stages additionally mounted on the rotor of large pumps because of the need to maintain both high pumping speeds and compression ratios with viscous fluids. FIG. 8 shows the finned rotor structure that was tested. Testing of the molecular drag stage with a similar disk without fins was also performed. These test results are shown in FIG. FIG.
Means compression (foreline or front pressure) (mb
ar) as a function. Curve 17
0 shows the performance of a molecular drag stage with a finned rotor and curve 172 shows the performance of a molecular drag stage with a conventional finless rotor. The compression of the finned rotor (curve 170) is higher at higher pressures (from 2 mbar to 1
0 mbar). The higher maximum compression ratio of prior art stages is due to the greater lateral separation between the rotor and the flow path walls.

FIGS. 9 and 10 show a second embodiment of the molecular drag stage according to the present invention. The illustrated molecular drag stage includes a rotor disk 200 and a stator, which are mounted in a housing as shown in FIG. 1 described above. The stator 202 forms a flow path 204, and the rotor disk 200 rotates in the flow path 204. The rotor disk 200 is mounted on a shaft (not shown) and rotates about a central axis 210.

The rotor disk 200 has two or more fins 220, 222, 224, which are uniformly fixed around the periphery thereof and are arranged in the flow path 204 with a space therebetween.
226. In the embodiment of FIGS.
20, 222, 224, 226 project axially within the channel 204 with respect to the axis 210. In the embodiment of FIGS. 9 and 10, the fins 220, 222
The fins 222 and 224 form a cross flow channel 232, and the fins 224 and 226 form a cross flow channel 234. The fins 220, 222, 224, 226 are fixed and project over the periphery of the rotor disk.
That is, the fins 220, 222, 224, and 226 are provided in a coaxial columnar shape. As in the embodiment of FIGS. 2-4, the size of the fins 220, 222, 224, 226 and the space between the fins is selected based on the desired performance of the molecular drag stage. Cross-flow sub-channel 2
The size of 30, 232, 234 is selected to provide the desired pumping speed.

The stator 202 includes a baffle 240 that blocks each of the peripherally located transverse flow channels. The fins and baffles have complementary geometries such that the baffle substantially blocks each crossflow sub-channel. In particular, baffle 2
40 includes a finger 242 projecting into the lateral flow sub-channel 230, a finger 244 projecting into the lateral flow sub-channel 232, and a finger 246 projecting into the lateral flow sub-channel 234. These fingers 242, 24
4, 246 are provided with fins 22 so as to provide a small clearance space between the rotor disk and the baffle 240.
0, 222, 224, and 226.
Stator 240 also forms inlets and outlets to each of the cross flow sub-channels 230, 232, 234, as described above in connection with FIGS.

Here, various molecular drag stages are included within the scope of the present invention. The number of fins in the molecular drag stage may be a practical number, and the size of the fins and the distance between the fins are specifically selected in the application. In the rotor disk 100 illustrated in FIGS. 2 to 4, the fins 120, 122, 124, 12
The size of the region 6 in the axial direction is larger than the size of the central region in the axial direction. Generally, the rotor disk has a uniform or non-uniform axial dimension and the stator has a complementary geometry. In a multi-stage vacuum pump, it is convenient to use a rotor disk having a uniform axial thickness. Additional fins may be provided on a rotor disk having an increasing axial thickness near its outer periphery. The size of the fins and the space between the fins is specifically selected for the application. In accordance with the present invention, a vacuum pump can include one or more molecular drag stages. Although the molecular drag stage of the present invention has been described as having fins fixed to the periphery of the rotor disk and baffles attached to the stator, the fins can be attached to either the rotor or the stator. In configurations where the fins overhang the stator in the cavity where the rotor disk rotates, a baffle may be attached to the rotor.

With reference to FIGS. 11 to 15, a description will be given of a molecular drag stage in which fins are provided on a stator. FIG.
15 to 15, the same components are denoted by the same reference numerals. Stator 300 has a substantially cylindrical inner peripheral wall 302 having a central axis 320. Annular fin 310,
312, 314 project inward from the cylindrical inner peripheral wall 302. These fins 310, 312, 314 are uniformly fixed around their periphery and are in the r-θ plane with respect to axis 320. Rotor disk 324, which is positioned for rotation about axis 320, includes flange 326 proximate fin 310 and flange 32 proximate fin 314.
8 is included. A flow path is formed between the flanges 326 and 328. The fins 310 and 312 and the rotor disk 324 form the cross flow sub-channel 330 and the fin 31
2, 314 and the rotor disk 324
32 are formed.

As shown in FIGS. 12 and 13, the rotor disk 324 includes baffles 340 and 342. The baffles 340, 342 are preferably spaced 180E about the axis 320 to ensure that the rotating rotor disk 324 is balanced. As shown in FIG. 12, the baffle 340 includes a finger 344 projecting into the sub flow path 330 and a finger 346 projecting into the sub flow path 332. These fingers 344, 346
Is about the same size as the fins 310, 312, 314 so as to provide a small clearance space between the baffle 340 and the fins 310, 312, 314. The fins and baffles have complementary geometries such that the baffle substantially blocks each crossflow sub-channel. The baffle 342 has a similar structure.

As shown in FIGS. 13 and 14, the rotor disk 324 is provided with inlets 350 and 352, and the inlets 350 and 352 are connected to the upper surface 3 of the rotor disk 324.
Extends downwardly from 54 to access the cross flow sub-channels 330, 332 adjacent to each baffle. Figures 13 and 14
As shown in the figure, the rotor disk 324 has an outlet 360,
362 are provided and these outlets 360, 362 extend upwardly from the lower surface 364 of the rotor disk 324 to access the cross flow channels 330, 332 adjacent to each baffle. The molecular drag stages of FIGS. 11-15 include an inlet and an outlet for each baffle. Inlet 350 and outlet 36
2 are disposed on both sides of the baffle 340, on the side opposite to the baffle 342. In such a configuration, it operates like two pumping stages in parallel, each consisting of half the circumference of the rotor disk. In operation, gas is received through inlets 350, 352,
This gas flows into the cross flow sub-channels 330 and 332. The gas is pumped over the periphery of the transverse sub-channel by molecular drag due to the rotation of the rotor disk 324. The gas then exits to the next stage or pump exhaust port through outlets 360,362.

In general, the molecular drag stage of the present invention includes a stationary element and a rotating element, which are arranged in tandem to permit rotation of the rotating element with respect to the stationary element. The stationary and rotating elements form a flow path having an inlet and an outlet. One of the fixed and rotating elements includes fins that are uniformly fixed around the periphery and are spaced apart from each other and arranged in the flow path. The fins define one or more crossflow sub-channels, each of which communicates with an inlet and an outlet. The other of the fixed and rotating elements is
Including a baffle arranged in the flow path. The baffles and fins have complementary geometries such that the baffle substantially blocks the crossflow sub-channel. That is, the fins may rotate as in the embodiments of FIGS. 2-6, 9 and 10, or may be fixed as in the embodiments of FIGS. When the fins are secured, the baffle rotates about the fins.

While the preferred embodiment of the present invention has been described above, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention, which is defined by the appended claims. It is clear.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view of a high vacuum pump including an axial turbo molecular compressor and a molecular drag compressor.

FIG. 2 is a plan sectional view of a first embodiment of a molecular drag vacuum pumping stage according to the present invention.

FIG. 3 is a partial side cross-sectional view of the molecular drag vacuum pumping stage of FIG. 2, showing a cross flow sub-channel formed by rotor fins.

FIG. 4 is a side partial cross-sectional view of the molecular drag stage of FIG. 2, showing a fixed baffle between an inlet and an outlet.

FIG. 5 is a partial side sectional view of the molecular drag stage of FIG. 2, showing a first example of an inlet configuration;

FIG. 6 is a partial side sectional view of the molecular drag stage of FIG. 2, showing a second example of an inlet configuration.

FIG. 7 is a graph of compression as a function of pressure, showing the performance of a molecular drag stage of the present invention and a prior art molecular drag stage.

8 is a side partial cross-sectional view of a molecular drag stage used in a performance comparison test with the conventional molecular drag stage performance of FIG. 7;

FIG. 9 is a partial side cross-sectional view of a second embodiment of a molecular drag stage according to the present invention, illustrating a cross-flow sub-channel formed by rotor fins.

FIG. 10 is a side partial cross-sectional view of the molecular drag stage of FIG. 9, showing a fixed baffle.

FIG. 11 is a partial cross-sectional view of a third embodiment of a molecular drag stage according to the present invention, illustrating a cross-flow sub-channel formed by stator fins.

FIG. 12 is a partial side cross-sectional view of the molecular drag stage of FIG. 11, showing the baffle formed by the rotor.

FIG. 13 is a sectional view of the rotor shown in FIGS. 11 and 12;

FIG. 14 is a plan view of the rotor shown in FIGS. 11 and 12;

FIG. 15 is a bottom view of the rotor shown in FIGS. 11 and 12;

[Explanation of symbols]

 100: Rotor disk 102: Stator 104: Flow path 110: Axis line 120, 122, 124, 126: Fin 130, 132, 134: Cross flow sub-flow path

Claims (23)

[Claims] 1. A molecular drag vacuum pumping stage, comprising: (1) a stationary element; and (2) a rotating element, wherein the stationary element and the rotating element permit rotation of the rotating element with respect to the stationary element. The fixed element and the rotating element form a flow path having an inlet and an outlet, and one of the fixed element and the rotating element is uniformly fixed around the periphery thereof. Fins spaced apart from each other and arranged in the flow path, wherein the fins form one or more cross flow sub-flow paths, and each of the cross flow sub-flow paths communicates with the inlet and the outlet. The other of the fixed element and the rotating element has a baffle arranged in the flow path, wherein the baffle and the fin are complementary such that the baffle substantially blocks the cross flow sub-flow path Na geo A molecular drag vacuum pumping stage having a metrology wherein gas is pumped from the inlet through the cross flow sub-flow path to the outlet as the rotating element rotates with respect to the stationary element. 2. The molecular drag vacuum pumping stage of claim 1 wherein said fins are attached to said rotating element and said baffles are attached to said stationary element. 3. The molecular drag vacuum pumping stage of claim 1 wherein said fins are attached to said stationary element and said baffles are attached to said rotating element. 4. The molecular drag vacuum pumping stage of claim 1, wherein said cross flow sub-channel has a total cross-sectional area that determines a pumping speed of said molecular drag vacuum pumping stage. 5. The molecular drag vacuum pumping stage of claim 1, wherein said fins project radially about an axis of rotation of said rotating element. 6. The molecular drag vacuum pumping stage of claim 1, wherein said fins project axially with respect to the axis of rotation of said rotating element. 7. The molecular drag vacuum pumping stage of claim 1, wherein said fins form a plurality of transverse sub-channels. 8. A molecular drag vacuum pumping stage comprising: (1) a rotor disk coupled to a drive shaft that rotates about an axis; and (2) a flow path arranged around the rotor disk and having an inlet and an outlet. A stator formed and (3) a baffle arranged in the flow passage, wherein two or more of the rotor disks are uniformly fixed around the periphery thereof and arranged in the flow passage with a space therebetween. Wherein the fins form one or more transverse sub-channels, each transverse sub-channel communicates with the inlet and the outlet, and wherein the baffle and the fin are such that the baffle is the one Having a complementary geometry to substantially obstruct the cross flow sub-flow path, wherein when the rotating element rotates with respect to the stationary element, gas flows from the inlet into the one or more transverse flow paths. The pumped to the outlet through the sub-channel molecular drag vacuum pumping stage as place. 9. The molecular drag vacuum pumping stage of claim 8, wherein said fins project radially within said flow path. 10. The molecular drag vacuum pumping stage of claim 8, wherein said fins project axially within said flow path. 11. The molecular drag vacuum pumping stage of claim 8, wherein said fins define a plurality of transverse sub-channels. 12. The molecular drag vacuum pumping stage of claim 8, wherein said baffle includes fingers extending into each of said one or more crossflow sub-channels. 13. A pump housing having an axis, an axial turbo-molecular compressor arranged within said housing,
A molecular drag compressor arranged in the housing, each of the axial turbo molecular compressor and the molecular drag compressor having a rotating portion coupled to a single motor drive shaft aligned coaxially with the axis. An integrated high vacuum pump, wherein the molecular drag compressor includes at least one molecular drag stage, wherein the molecular drag stage is coupled to a drive shaft that rotates about an axis; A stator arranged around the rotor disk and having a flow path having an inlet and an outlet, and (3) a baffle arranged in the flow path, wherein the rotor disk is uniformly distributed over the periphery thereof. Having two or more fins fixed and spaced from each other in the flow path, wherein the fins form one or more cross flow sub-flow paths; Wherein each baffle communicates with the inlet and the outlet, and wherein the baffle and the fin have complementary geometries such that the baffle substantially blocks the one or more baffle sub-channels; An integrated high vacuum pump, wherein gas is pumped from the inlet through the one or more crossflow sub-channels to the outlet as the rotating element rotates with respect to the stationary element. 14. The integrated high vacuum pump of claim 13, wherein said fins project radially within said flow path. 15. The integrated high vacuum pump of claim 13, wherein said fins project axially within said flow path. 16. The integrated high vacuum pump of claim 13, wherein said fins define a plurality of transverse sub-channels having a total cross-sectional area that determines a pumping speed of said molecular drag vacuum pumping stage. 17. The integrated high vacuum pump of claim 13, wherein said baffle includes fingers that extend into each of said one or more crossflow sub-channels. 18. A pump housing having an axis, an axial turbo-molecular compressor arranged in the housing,
A molecular drag compressor arranged in the housing, each of the axial turbo molecular compressor and the molecular drag compressor having a rotating portion coupled to a single motor drive shaft aligned coaxially with the axis. An integrated high vacuum pump, wherein the molecular drag compressor includes at least one molecular drag stage, wherein the molecular drag stage comprises: (1) a fixed element; and (2) a rotating element. An element and the rotating element are arranged in cooperation to allow rotation of the rotating element with respect to the stationary element, wherein the stationary element and the rotating element form a flow path having an inlet and an outlet; And one of the rotating elements has fins that are uniformly fixed around the periphery thereof and are arranged in the flow path with a space therebetween, and the fin has one or more fins. Wherein each of the transverse sub-channels communicates with the inlet and the outlet, and the other of the fixed element and the rotating element has a baffle arranged in the channel. The baffle and the fins have complementary geometries such that the baffle substantially obstructs the crossflow sub-flow path, wherein when the rotating element rotates with respect to the stationary element, gas flows from the inlet to the crossflow sub-flow. An integrated high vacuum pump where the pump is pumped to the outlet through a flow path. 19. The fin is attached to the rotating element and the baffle is attached to the fixed element.
19. The integrated high vacuum pump of claim 18. 20. The fin is attached to the fixed element and the baffle is attached to the rotating element.
19. The integrated high vacuum pump of claim 18. 21. A molecular drag vacuum pumping stage, comprising: (1) a stationary element; and (2) a rotating element, wherein the stationary element and the rotating element permit rotation of the rotating element with respect to the stationary element. The fixed element and the rotating element form a flow path having an inlet and an outlet, and the rotating element is uniformly fixed around the periphery thereof and is spaced apart from each other. Wherein the fins define one or more transverse sub-channels, each transverse sub-channel communicating with the inlet and the outlet, and A baffle arranged in a path, wherein the baffle and the fin have a complementary geometry such that the baffle substantially obstructs the cross flow sub-flow path, and wherein the rotating element rotates relative to the stationary element. Then, the gas is pumped into the outlet through the lateral flow subchannels from said inlet, molecular drag vacuum pumping stage where. 22. The molecular drag vacuum pumping stage of claim 21, wherein said inlet is disposed axially. 23. The molecular drag vacuum pumping stage of claim 21, wherein said inlet is radially disposed.