Vacuum pumps with auxiliary pumping stages
a technology of vacuum pumps and auxiliary pumping stages, applied in the direction of non-positive displacement pumps, liquid fuel engines, mechanical devices, etc., can solve the problem of limited efficiency under certain operating conditions
Inactive Publication Date: 2008-10-16
VARIAN INC
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Benefits of technology
[0008]According to a first aspect of the invention, vacuum pumping apparatus comprises a housing, one or more primary pumping stages disposed in the housing, a motor coupled to the primary pumping stages, the motor including at least one stationary surface and at least one moving surface when the motor is energized, the stationary and moving surfaces of the motor defining an auxiliary pumping stage coupled in series with the primary pumping stages to pump gas through a pumping channel between the stationary and moving surfaces of the motor, the housing having a first exhaust port between the primary pumping stages and the auxiliary pumping stage, and a second exhaust port at an outlet of the auxiliary pumping stage, and a valve connected in series with the first exhaust port and configured to close when an inlet pressure of the vacuum pumping apparatus is below a predetermined pressure.
[0009]According to a second aspect of the invention, a method is provided for operating vacuum pumping apparatus of the type including a
Problems solved by technology
Known vacuum pump structures have certain drawbacks, including but not limited to the need for a roughing vacuum pump in many applications and limited efficiency under certain operating conditions.
Method used
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[0017]A prior art high vacuum pump is shown in FIG. 1. An upper housing 10 defines an interior chamber 12 having an inlet port 14. The housing 10 includes a vacuum flange 18 for sealing the inlet port 14 to a vacuum chamber (not shown) to be evacuated. A motor housing 15 includes an exhaust port 16. The exhaust port 16 is typically connected to a roughing vacuum pump (not shown). In cases where the vacuum pump is capable of exhausting to atmospheric pressure, the roughing vacuum pump is not required. Located within housing 10 is an axial turbomolecular compressor 20, which typically includes several axial turbomolecular stages, and a molecular drag compressor 22, which typically includes several molecular drag stages. Each stage of the axial turbomolecular compressor 20 includes a rotor 24 and a stator 26. Each rotor and stator has inclined blades as is known in the art. Each stage of the molecular drag compressor 22 includes a rotor disk 30 and a stator 32. The rotor 24 of each tur...
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Vacuum pumping apparatus includes a housing, one or more primary pumping stages disposed in the housing, a motor coupled to the primary pumping stages, the motor including at least one stationary surface and at least one moving surface when the motor is energized, the stationary and moving surfaces of the motor defining an auxiliary pumping stage coupled in series with the primary pumping stages to pump gas through a pumping channel between the stationary and moving surfaces of the motor, the housing having a first exhaust port between the primary pumping stages and the auxiliary pumping stage, and a second exhaust port at an outlet of the auxiliary pumping stage, and a valve connected in series with the first exhaust port and configured to close when an inlet pressure of the vacuum pumping apparatus is below a predetermined pressure.
Description
FIELD OF THE INVENTION[0001]This invention relates to high vacuum pumps and, more particularly, to high vacuum pumps and methods for vacuum pumping that include one or more auxiliary pumping stages. The invention relates to vacuum pumps of the type which incorporate an electric motor, such as for example turbomolecular pumps, molecular drag pumps and hybrid pumps.BACKGROUND OF THE INVENTION[0002]Conventional turbomolecular vacuum pumps include a housing having an inlet port, an interior chamber containing a plurality of axial pumping stages, and an exhaust port. The exhaust port is typically attached to a roughing vacuum pump. Each axial pumping stage includes a stator having inclined blades and a rotor having inclined blades. The rotor and stator blades are inclined in opposite directions. The rotor blades are rotated at high speed by a motor to pump gas between the inlet port and the exhaust port. A typical turbomolecular vacuum pump may include six to twelve axial pumping stages....
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Login to View More IPC IPC(8): F04B5/00
CPCF04D19/042F04D25/0606F04D29/522F04D19/046
Inventor HABLANIAN, MARSBED
Owner VARIAN INC