Turbomolecular Pump Blocking Stage for Spindle Bearing Protection
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Solution Overview
Problem
Turbomolecular pumps are susceptible to external influences such as process gases and ambient dust, which can affect the spindle unit components, particularly the bearing system, especially when active magnetic bearings are used.
Innovation Solution
A blocking stage is arranged in the intermediate space between the spindle housing and the rotor, formed by structures on the outside of the spindle housing and/or inside of the rotor, acting as a barrier to prevent the ingress of contaminants, and can include labyrinth seals or Holweck pump stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the spindle housing is left open to allow access to components, then ease of maintenance is improved, but contamination from process gases and dust worsens
Solution Approach 1:
The pump is divided into two pressure zones: a high-vacuum zone containing the rotor and stators, and a lower-vacuum zone containing the spindle housing with bearing cartridge. The blocking stage creates a physical segmentation between these zones, allowing the spindle housing to be accessed for maintenance while the high-vacuum components remain protected from contamination.
Solution Approach 2:
The blocking stage acts as an intermediary barrier between the process gas pathway and the spindle housing. It prevents direct contact between process gases and the bearing cartridge while still allowing the spindle unit to be removed and serviced. The blocking stage mediates between the need for component accessibility and the need for contamination protection.
2Reliability
If the blocking stage is formed by separate components placed in the gap, then protection effectiveness is improved, but device complexity worsens
Solution Approach 1:
The blocking stage is merged with either the rotor or the spindle housing, forming an integrated structure rather than a separate component. This combining approach maintains the protective function while reducing the number of discrete parts, simplifying assembly and reducing potential failure points from additional components.
Solution Approach 2:
The structure that forms the blocking stage serves multiple functions: it is part of the rotor or housing structure, provides mechanical support, and simultaneously acts as a barrier to process gases. This multi-functionality reduces the need for additional dedicated blocking components, thereby reducing overall device complexity.
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
Effectively protects the spindle unit components from external contaminants, ensuring the integrity of the pump's internal components by preventing the ingress of process gases and other impurities.
Implementation Method 1
The blocking stage can include labyrinth seals
Implementation Method 2
A blocking stage is arranged in the intermediate space between the spindle housing and the rotor, formed by structures on the outside of the spindle housing and/or inside of the rotor, acting as a barrier to prevent the ingress of contaminants
Implementation Method 3
a pumping system effective in a pumping direction from the inlet to the outlet and comprising at least one turbomolecular pumping stage, which has a rotor comprising rotor elements and stator elements that interact with the rotor elements during operation to effectively pump
Data Source
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AI summary
The invention relates to a turbomolecular pump with an inlet, an outlet, a pumping system operating in a pumping direction from the inlet to the outlet and comprising at least one turbomolecular pumping stage, the pumping system comprising a rotor with rotor elements and stator elements that interact with the rotor elements during operation to effectively pump, and a spindle unit comprising a spindle housing and, within the spindle housing, a shaft rotatably connected to the rotor, and for the shaft a drive motor and a bearing arrangement, wherein the shaft can be driven into rotation about an axis of rotation by means of the drive motor and is rotatably mounted by the bearing arrangement, wherein the spindle housing is at least partially surrounded by the rotor, and wherein at least one blocking stage is arranged in an intermediate space between the spindle housing and the rotor, which blocks at least one direction, in particular for a process gas pumped by the pumping system,has a blocking effect and is formed by an area on the outside of the spindle housing and/or by an area on the inside of the rotor.