Vacuum Pump Sealing Stage for Rotor Shaft Gap Isolation
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Solution Overview
Problem
Existing turbomolecular pumps face issues with corrosive gases leaking through the gap between the rotor shaft and partition wall, leading to damage and premature failure, and are costly to manufacture with high power requirements and increased axial height due to labyrinth seals.
Innovation Solution
A turbomolecular pump utilizing a Siegbahn pump stage with radially oriented disk-shaped stator and rotor elements, which creates an effective barrier between the working and storage spaces without increasing manufacturing costs, power requirements, or reducing service life, and achieves a sealing gap with minimal axial height increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a labyrinth seal is provided between the rotor shaft and partition wall to prevent gas exchange, then the sealing effect is improved, but the axial overall height and power requirement increase significantly
Solution Approach 1:
The invention extracts the sealing function from the traditional labyrinth seal structure and relocates it to a dedicated sealing stage. This sealing stage is positioned between the working space and storage space, separating the sealing function from the main pump structure. By doing so, the axial height increase is localized rather than affecting the entire pump assembly, and the power consumption for sealing is isolated from the main pumping power requirements.
Solution Approach 2:
The pump is segmented into distinct functional stages: a pumping stage for gas compression and a separate sealing stage for preventing gas exchange. This segmentation allows each stage to be optimized independently - the pumping stage for maximum pumping efficiency and the sealing stage for minimal axial height and power consumption while maintaining effective sealing.
2Reliability
If a labyrinth seal with narrow gaps is provided to achieve high sealing effect, then the sealing performance is improved, but the manufacturing costs increase and the rotor disk experiences unfavorable mechanical stresses
Solution Approach 1:
The sealing function is extracted from the rotor disk structure and placed in a separate sealing stage. This eliminates the need for complex axial grooves and projections in the rotor disk, avoiding the unfavorable mechanical stresses and high manufacturing costs associated with traditional labyrinth seals. The sealing stage can be manufactured as a separate component with simpler geometry.
Solution Approach 2:
The sealing function is separated into an independent sealing stage rather than being integrated into the rotor disk. This segmentation allows the sealing components to be manufactured separately using simpler processes, reducing the overall manufacturing complexity and cost while maintaining effective sealing performance.
3Reliability
If a labyrinth seal is provided to prevent gas exchange between working space and storage space, then the sealing effect is improved, but the power requirement increases due to gas friction in narrow gaps
Solution Approach 1:
The sealing function is extracted and placed in a dedicated sealing stage, allowing the main pumping stage to operate without the additional power consumption associated with gas friction in labyrinth seal gaps. The sealing stage consumes minimal power independently, separate from the main pumping power requirements.
Solution Approach 2:
By segmenting the pump into pumping and sealing stages, the power consumption is separated into distinct components. The sealing stage requires minimal power for maintaining the seal, while the pumping stage consumes power only for the pumping action, eliminating the additional power loss from gas friction in narrow gaps that would occur in an integrated labyrinth seal design.
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
The Siegbahn pump stage effectively prevents gas flow between the working and storage spaces, ensuring the storage space is closed off from harmful gases, maintaining operational reliability and reducing manufacturing and operational costs while maintaining a compact design.
Implementation Method 1
a pumping effect between the working space and the storage space that passes through the gap is generated
Data Source
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AI summary
A vacuum pump comprising a working chamber, a storage chamber, a partition wall arranged between the working chamber and the storage chamber, and at least one rotor shaft extending through the partition wall and forming a gap with the partition wall, as well as a locking device for isolating the working chamber and the storage chamber. The locking device is formed by a sliding pump stage designed to provide a pumping action through the gap between the working chamber and the storage chamber.