Cryopump Baffle Design for Heat Radiation Shielding
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Solution Overview
Problem
Cryopumps face challenges in maintaining a vacuum state due to heat radiation from the vacuum chamber, which causes the cold head temperature to rise, making it difficult to condense gases like H2 and He, and ultimately leading to a failure in maintaining the required vacuum environment.
Innovation Solution
The implementation of a baffle system within the cryopump that includes intersecting gas passages and strategically arranged baffle elements to redirect and reflect heat radiation away from the cold head, ensuring it remains in a cryogenic state, thereby maintaining the vacuum environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cold head temperature is reduced below 15K to condense gases, then gas condensation capability is improved, but heat radiation from the vacuum chamber causes temperature rise making it difficult to maintain
Solution Approach 1:
A baffle structure is introduced as an intermediary element between the vacuum chamber and the cold head. The baffle includes intersecting first and second portions that create a shielded cavity, blocking direct heat radiation paths from the vacuum chamber to the cold head while allowing gas molecules to reach the cold head for condensation.
Solution Approach 2:
The baffle structure extends into the vacuum chamber space, creating a three-dimensional shielded region. The intersecting portions of the baffle form a cavity that blocks radiation from multiple directions, effectively adding spatial dimensions to the heat protection mechanism.
2Object-affected harmful factors
If a baffle structure is added to block heat radiation, then heat protection is improved, but device complexity increases
Solution Approach 1:
The baffle is divided into distinct first and second portions that intersect to form the shielded cavity. This segmentation allows the complex shielding function to be achieved through simpler, modular components that can be manufactured and assembled separately.
3Object-affected harmful factors
If the baffle completely covers the suction port projection, then heat radiation blocking is improved, but gas flow passage area is reduced
Solution Approach 1:
The baffle structure provides localized shielding where it is most needed (direct radiation paths to the cold head) while maintaining open passages for gas flow. The intersecting portions create a cavity that blocks radiation from specific directions without obstructing the overall gas flow path to the cold head.
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 solution effectively reduces direct heat radiation to the cryopump's interior, keeping the cold head at a cryogenic state, enhancing the pumping capacity and prolonging the service life of the cryopump by preventing temperature rises and ensuring efficient gas condensation.
Implementation Method 1
heat radiation of the vacuum chamber will affect the temperature of the cold head
Implementation Method 2
redirect and reflect heat radiation away from the cold head
Implementation Method 3
cooling and adsorbing the gas within in the cryopump
Implementation Method 4
cooling and adsorbing the gas within in the cryopump
Data Source
AI summary
The embodiments of the present disclosure relates a cryopump including a pump housing including a suction port, a cold head located within the pump housing, a shielding element located within the pump housing and covering the cold head, a baffle at the suction port, the baffle including a gas passage with an inlet and an outlet, an orthographic projection of the baffle to the cross section of the pump housing completely covers an orthographic projection of the suction port thereto, the gas passage includes a first portion and a second portion intersecting with each other, the inlet is defined by one end of the first portion, the outlet is defined by one end of the second portion.