NEG Auxiliary Vacuum Pump Layout for Low-Vibration Evacuation
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Solution Overview
Problem
Existing vacuum pumping systems face challenges with mechanical vibrations from turbomolecular pumps, leading to decreased evacuation performance and increased system size and complexity, particularly in applications like Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), and existing combinations of pumps are not optimized for ease of installation and energy efficiency.
Innovation Solution
An auxiliary pumping system comprising a primary pump connected to an intermediate vacuum chamber through a flexible conduit, with a high-pressure Non-Evaporable Getter (NEG) pump inside, maintaining a specific distance and volume ratio to minimize vibration impact and optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If turbomolecular pumps are used to achieve ultra high vacuum, then vacuum level is improved, but mechanical vibrations increase and system size increases
Solution Approach 1:
A flexible vacuum conduit is introduced as an intermediary element between the turbomolecular pump and the vacuum chamber. This conduit acts as a vibration isolator, absorbing mechanical vibrations while maintaining vacuum integrity, thus allowing the pump to achieve ultra high vacuum without transmitting harmful vibrations to the chamber
Solution Approach 2:
The turbomolecular pump is extracted from direct mounting on the vacuum chamber and placed at a distance connected by a flexible conduit. This separation removes the source of mechanical vibrations from the sensitive chamber environment while preserving the pump's vacuum generation capability
2Object-affected harmful factors
If turbomolecular pumps are installed far from the vacuum chamber to reduce vibrations, then mechanical vibrations are reduced, but evacuation performance decreases
Solution Approach 1:
The physical properties of the connection between pump and chamber are changed by using a flexible conduit with specific characteristics (length, flexibility, vacuum tightness). This allows optimizing the balance between vibration isolation and evacuation performance by adjusting conduit parameters rather than simply increasing distance
3Manufacturing precision
If multiple pumps are combined to evacuate the vacuum chamber, then vacuum level is improved, but system complexity increases
Solution Approach 1:
A roughing pump and turbomolecular pump are merged into a single integrated vacuum system with a common vacuum chamber. The system combines the high vacuum capability of the turbomolecular pump with the roughing capability of the roughing pump, eliminating the need for separate pumping systems and reducing overall complexity
4Productivity
If the volume of the getter pump is increased to improve pumping performance, then evacuation performance is improved, but system size increases
Solution Approach 1:
The pumping performance is enhanced by optimizing the ratio between getter material volume and pump chamber volume, and by controlling the activation temperature and pressure parameters. This allows achieving high evacuation performance with a compact pump design rather than simply increasing overall pump size
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 system reduces mechanical vibrations, minimizes system size and energy consumption, and enhances adaptability to various devices by using NEG pumps, offering improved performance and efficiency.
Implementation Method 1
a high-pressure Non-Evaporable Getter (NEG) pump contained in the intermediate vacuum chamber, wherein the primary pump operates from atmospheric pressure to a first level of vacuum and the NEG pump operates from said first level of vacuum to a second level of vacuum
Data Source
AI summary
The present invention concerns an auxiliary pumping system (1000) for evacuating an equipment chamber (1), comprising a primary pump (12), an intermediate vacuum chamber (10) connected to the primary pump (12) through a vacuum conduit (14), and a high-pressure Non-Evaporable Getter (NEG) pump contained in the intermediate vacuum chamber (10), wherein the vacuum conduit (14) has a length comprised between 5 and 200 cm and the ratio between the volume of the high-pressure NE pump and the volume of the intermediate vacuum chamber (10) is comprised between 0.022 and 0.540.