Cryopump Regeneration with Staged Heating to Prevent Convection Cooling
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Solution Overview
Problem
Cryopumps require efficient regeneration methods to release trapped gases, but existing techniques are inefficient due to prolonged heating times caused by convection cooling from purge gases, which can prevent the cryopump from reaching target temperatures.
Innovation Solution
A cryopump system that uses a purge gas to heat the cryopanel to a first temperature zone above the melting point of water, then suspends purge gas supply and utilizes a separate heat source to further heat the cryopanel to a second temperature zone higher than the purge gas temperature, enhancing heating efficiency by mitigating cooling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If purge gas is continuously supplied to heat the cryopanel, then the cryopanel temperature increases, but convection cooling from the purge gas prevents the cryopump from reaching target temperatures efficiently
Solution Approach 1:
The purge gas supply is operated periodically rather than continuously. The control unit opens the purge valve to supply purge gas for heating, then closes it to suspend supply, creating periodic heating cycles that avoid continuous convection cooling while still achieving temperature increases
Solution Approach 2:
Purge gas is supplied in advance to heat the cryopanel to a first temperature zone above the melting point of water before using the main heat source. This preliminary heating reduces the burden on the heat source and prepares the system for more efficient subsequent heating
2Temperature
If purge gas supply is used for heating, then the cryopanel reaches higher temperatures, but the regeneration time is prolonged due to cooling effects
Solution Approach 1:
The control unit implements periodic purge gas supply by opening and closing the purge valve at predetermined intervals. This allows the system to accumulate heat during purge gas supply periods while minimizing cooling effects by suspending supply during heating periods, thereby reducing overall regeneration time
Solution Approach 2:
The harmful convection cooling effect is extracted and eliminated by suspending purge gas supply during the heating phase. The control unit specifically closes the purge valve to stop the cooling effect while the heat source is operating, separating the heating and cooling functions in time
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 method allows for rapid and efficient heating of cryopump components, reducing regeneration time and ensuring effective discharge of gases, particularly water, by preventing convection cooling and allowing for higher temperature attainment.
Implementation Method 1
supplying a purge gas to a cryopump in order to heat a cryopanel to a first temperature zone higher than the melting point of water
Implementation Method 2
heating the cryopanel from the first temperature zone to a second temperature zone higher than a purge gas temperature
Implementation Method 3
A cryopump is a vacuum pump that traps and pumps gas molecules by condensing or adsorbing them on cryopanels cooled to ultracold temperatures
Implementation Method 4
A cryopump is a vacuum pump that traps and pumps gas molecules by condensing or adsorbing them on cryopanels cooled to ultracold temperatures
Data Source
AI summary
A method of regenerating a cryopump includes: supplying a purge gas to a cryopump in order to heat a cryopanel to a first temperature zone higher than the melting point of water; suspending supply of the purge gas to the cryopump while a cryopanel temperature is in the first temperature zone, and heating the cryopanel from the first temperature zone to a second temperature zone higher than a purge gas temperature.