Holweck Stator Sleeve with Variable Thread Geometry
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Solution Overview
Problem
Existing vacuum pumps, particularly turbomolecular vacuum pumps, have limited design flexibility in adjusting Holweck pump stage parameters such as suction and compression capacity and power consumption due to fixed axial extensions of Holweck-Stator sleeves, restricting fine-tuned adjustments.
Innovation Solution
The design of the Holweck-Stator sleeve features varying thread geometry along its axial extension, with different thread sections having distinct parameters like the number of bridges, width, and height, allowing for incremental changes in compression and suction capacities without increasing axial length, enabling more precise control over pump performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the Holweck stator sleeve is formed by several separate sleeve sections arranged axially one behind the other to adjust thread parameters, then the parameters of the Holweck pump stage (suction capacity, compression capacity, power consumption) can be adjusted, but the axial extension of the stator sleeve increases and is limited by manufacturing and assembly reasons
Solution Approach 1:
The stator sleeve is divided into multiple axially arranged threaded sections, each with different thread parameters (number of lands, thread pitch, groove width). This segmentation allows independent optimization of each section's pumping characteristics while maintaining a compact overall structure, resolving the contradiction between parameter adjustability and axial length limitation.
Solution Approach 2:
Different sections of the stator sleeve are assigned different thread geometries optimized for specific functions: the first section has parameters optimized for suction capacity, the second section for compression capacity, and the third section for final compression. This local differentiation of properties allows fine-tuned adjustment of pump stage parameters without increasing the overall axial extension.
2Ease of manufacture
If the Holweck geometry is kept constant across the axial extent of the stator sleeve for manufacturing simplicity, then manufacturing and assembly are easier, but the parameters of the Holweck pump stage can only be adjusted to a limited extent
Solution Approach 1:
The stator sleeve is divided into multiple axially arranged threaded sections, each with different thread parameters (number of lands, thread pitch, groove width). This segmentation allows independent optimization of each section's pumping characteristics while maintaining a compact overall structure, resolving the contradiction between parameter adjustability and axial length limitation.
Solution Approach 2:
Different sections of the stator sleeve are assigned different thread geometries optimized for specific functions: the first section has parameters optimized for suction capacity, the second section for compression capacity, and the third section for final compression. This local differentiation of properties allows fine-tuned adjustment of pump stage parameters without increasing the overall axial extension.
3Length of moving object
If the axial extension of the stator sleeve is minimized for compact design, then the pump size is reduced, but the ability to finely adjust parameters through multiple sleeve sections is lost
Solution Approach 1:
The stator sleeve is divided into multiple axially arranged threaded sections, each with different thread parameters (number of lands, thread pitch, groove width). This segmentation allows independent optimization of each section's pumping characteristics while maintaining a compact overall structure, resolving the contradiction between parameter adjustability and axial length limitation.
Solution Approach 2:
Different sections of the stator sleeve are assigned different thread geometries optimized for specific functions: the first section has parameters optimized for suction capacity, the second section for compression capacity, and the third section for final compression. This local differentiation of properties allows fine-tuned adjustment of pump stage parameters without increasing the overall axial extension.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for finer adjustments in suction and compression capacities and power consumption of the Holweck pump stage, enhancing operational flexibility and efficiency by modifying thread parameters in small steps, even with minimal axial extensions, thus overcoming manufacturing and assembly constraints.
Implementation Method 1
Holweck pumping stages generally belong to the class of molecular vacuum pumps and generate a molecular flow by rotating a Holweck rotor relative to a stationary Holweck stator
Data Source
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AI summary
The present invention relates to a vacuum pump with at least one Holweck pumping stage having an inlet and an outlet downstream of the inlet in the pumping direction. The Holweck pumping stage comprises a Holweck rotor with a rotor sleeve and a Holweck stator with a stator sleeve arranged coaxially to the Holweck rotor, forming a Holweck gap. The stator sleeve has a Holweck thread with multiple thread grooves bounded by webs formed on the stator sleeve and by a groove base formed by the stator sleeve. The stator sleeve is formed in one piece, and at least one thread parameter of the Holweck thread from the group of thread parameters consisting of the number of webs, the thread pitch, the width of the thread grooves, the width of the webs, and the height of the webs above the groove base changes along the axial extent of the stator sleeve.