Turbomolecular Pump Stage Geometry for Compact Axial Height
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Solution Overview
Problem
Conventional turbomolecular vacuum pumps face challenges in reducing axial height without compromising pumping speed, as the geometric parameters of rotor and stator disks influence performance.
Innovation Solution
The design of the most upstream turbomolecular pump stage is optimized by maintaining a ratio of 3 ≤ H/h ≤ 5 for rotor and stator disk heights, allowing for a compact pump without significant performance loss, where H is the rotor disk vane height and h is the stator disk vane height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of pumping stages is increased to maintain pumping speed, then the axial height of the pump increases
Solution Approach 1:
The invention changes the geometric parameters of the pump stages, specifically setting the ratio of rotor disk vane height (H) to stator disk vane height (h) within 3 ≤ H/h ≤ 5 in the most upstream stage. This parameter optimization allows reduction of axial height while maintaining pumping speed performance.
2Length of moving object
If the axial height of the pump is reduced, then the geometric parameters of rotor and stator disks must be optimized, but conventional designs require stator disk blade height to be at least half of rotor disk blade height
Solution Approach 1:
The invention fundamentally changes the conventional geometric parameter relationship by setting H/h ratio between 3 and 5, where H is rotor disk vane height and h is stator disk vane height. This breaks the conventional rule that stator blades should be at least half the height of rotor blades, enabling compact design.
Solution Approach 2:
The invention applies different geometric parameter ratios to different pump stages, with the most upstream stage having H/h ratio of 3-5, while other stages can use conventional ratios. This localized optimization reduces overall axial height without compromising overall pumping performance.
Data Source
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AI summary
The present invention relates to a turbomolecular vacuum pump with a pump inlet, a pump outlet, and a pumping mechanism driven by a rotor shaft for conveying a process gas from the pump inlet to the pump outlet. The pumping mechanism comprises several turbomolecular pumping stages connected in series between the pump inlet and the pump outlet, each with a rotor disk and a stator disk downstream of the rotor disk. Each rotor disk has several radially extending vanes that have a height H parallel to the rotor shaft. Each stator disk also has several radially extending vanes that have a height h parallel to the rotor shaft. The ratio H/h of the most upstream turbomolecular pumping stage is: 3 ≤ H/h ≤ 5.