Cryopump Lattice Adsorption Panels for Non-Condensable Gas Pumping
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Solution Overview
Problem
Cryopumps face challenges in effectively pumping non-condensable gases like hydrogen, as adsorbent materials can accumulate adhesive materials from ion implantation processes, leading to reduced pumping performance over time, requiring frequent maintenance and regeneration.
Innovation Solution
A cryopump design featuring a radiation shield and a cryopanel assembly with a lattice-shaped adsorption panel arrangement, where the adsorption sections are exposed to the radiation shield side portion, enhancing the capture of non-condensable gases and protecting adsorption areas from condensable gases and moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If adsorbent materials are used to pump non-condensable gases, then pumping performance is achieved, but adhesive materials accumulate on the adsorbent leading to reduced performance over time
Solution Approach 1:
The adsorption area is divided into multiple discrete adsorption sections arranged in a lattice pattern, with each section exposed to the shield side portion. This segmentation allows for better gas flow distribution and reduces accumulation of adhesive materials in any single location, maintaining pumping performance over time.
Solution Approach 2:
The adsorption panels are arranged in a three-dimensional lattice structure with multiple layers between the shield opening and shield bottom portion. This vertical and spatial arrangement increases the effective adsorption area while preventing material accumulation by distributing gas molecules across multiple dimensions.
2Productivity
If adsorption area is increased to improve pumping speed, then non-condensable gas capture efficiency increases, but system complexity increases
Solution Approach 1:
The lattice-shaped adsorption panel arrangement serves multiple functions: it provides extensive adsorption area for high pumping speed, protects adsorption areas from condensable gases through the shield configuration, and reduces radiant heat exposure. This multi-functionality achieves high performance without proportionally increasing complexity.
Solution Approach 2:
The adsorption sections are nested within the lattice structure formed by the first and second panel arrangements, with the shield providing an enclosing structure. This nested configuration maximizes the use of available space while maintaining a compact overall structure.
3Productivity
If cryopanel assembly is cooled to lower temperature to improve adsorption efficiency, then non-condensable gas capture improves, but energy consumption increases
Solution Approach 1:
The shield structure, which initially might be seen as a protective barrier, is actually utilized to expose adsorption sections to the side portion where non-condensable gases are concentrated. This converts the shield's protective function into an advantage for enhancing adsorption efficiency of non-condensable gases while the cryopanel assembly maintains lower temperature for optimal performance.
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 lattice-shaped panel arrangement increases the pumping speed of non-condensable gases by 20% compared to previous designs, reducing the number of cryopumps needed and lowering system costs while maintaining efficient gas capture and protection of adsorption areas.
Implementation Method 1
adsorbing the non-condensable gas molecule on a lattice-like adsorption panel arrangement of the cryopanel assembly
Implementation Method 2
A cryopump is a vacuum pump that captures and pumps gas molecules by condensing or adsorbing molecules on a cryopanel cooled to an extremely low temperature
Data Source
AI summary
A cryopump includes: a radiation shield that includes a shield front end that defines a shield opening, a shield bottom portion, and a shield side portion that extends between the shield front end and the shield bottom portion; and a cryopanel assembly that is cooled to a lower temperature than that of the radiation shield. The cryopanel assembly includes a first panel arrangement including a plurality of first adsorption panels and a plurality of second panel arrangements each including a plurality of second adsorption panels. The first panel arrangement forms a multitude of adsorption sections arranged in a lattice-shaped pattern in cooperation with the plurality of second panel arrangements, each of the adsorption sections being exposed to the shield side portion.