Non-Planar Siegbahn Stage Groove Geometry
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Solution Overview
Problem
Existing Siegbahn stages in vacuum pumps require complex machining to achieve variable groove cross sections, leading to increased production costs and complexity.
Innovation Solution
The Siegbahn stage features non-planar, structured pumping surfaces with spiral grooves that can vary in height and width, allowing for simpler and more cost-effective production by maintaining a constant groove width, enabling adaptive groove cross-sections without multiple machining steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flat planar surfaces are used for the pump-active surfaces of stator and rotor elements, then the machining process is simple, but the groove cross-section cannot be varied efficiently
Solution Approach 1:
The pump-active surfaces are changed from flat planar surfaces to curved non-planar surfaces (conical or cylindrical). This dimensional change allows the groove cross-section to be varied by changing the surface curvature and orientation, enabling different groove geometries to be achieved through single-pass machining while maintaining manufacturing simplicity.
Solution Approach 2:
The invention varies the geometric parameters of the pump-active surfaces (curvature radius, cone angle, cylindrical radius) to achieve different groove cross-sections. By changing these surface parameters, the groove geometry can be adapted to different vacuum technology requirements without complicating the machining process.
2Manufacturing precision
If multiple machining steps are used to create variable groove cross-sections, then the groove geometry can be precisely controlled, but the production cost and complexity increase
Solution Approach 1:
The pump-active surfaces are pre-formed with specific curved geometries (conical or cylindrical shapes) before the groove machining process. This preliminary shaping of the surfaces allows subsequent groove machining to be performed in a single pass with precise control over the groove cross-section, eliminating the need for multiple machining steps while maintaining manufacturing precision.
3Ease of manufacture
If non-planar structured surfaces are used, then the production cost and complexity are reduced, but the surface geometry becomes more complex
Solution Approach 1:
The non-planar structured surfaces are applied locally only to the pump-active surfaces of the stator and rotor elements, while the rest of the components maintain simple geometries. This localized application of complex surface geometry reduces overall manufacturing complexity and cost while still achieving the benefits of variable groove cross-sections where needed.
Data Source
Figure 1~2
Figure 3
AI summary
A conduction stage of a vacuum pump, in particular a turbomolecular pump or a side-channel pump, comprises a stator element and a rotor element, each having one of two opposing pump-active surfaces, wherein at least the pump-active surfaces of the stator element comprise a structured surface. The opposing pump-active surfaces of the stator element and the rotor element are not planar.