Cryopump Controller Valve State Cooling Capacity
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Solution Overview
Problem
Cryopumps experience temperature overshoot during the crossover event when switching from rough pumping to cryopump evacuation, leading to potential delays in vacuum processes and reduced exhaust performance due to inadequate cooling capacity control.
Innovation Solution
A cryopump with a controller that detects the gate valve's closed state and increases the cryocooler's cooling capacity when closed, compared to when open, to mitigate temperature overshoot by adjusting the cryocooler's operation frequency and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cryocooler operates at standard cooling capacity during gate valve closure, then energy consumption is reduced, but temperature overshoot occurs during crossover events
Solution Approach 1:
The cryocooler operates in two dynamic modes: a first operation mode during gate valve closure with reduced cooling capacity to save energy, and a second operation mode during gate valve opening with increased cooling capacity to prevent temperature overshoot. The controller dynamically switches between these modes based on gate valve state detection.
Solution Approach 2:
The controller detects the gate valve closure state in advance and adjusts the cryocooler operation mode accordingly. By preliminarily switching to the first operation mode before crossover events occur, the system prepares to handle the incoming gas load efficiently when the valve opens, preventing temperature overshoot while minimizing energy consumption during valve closure.
2Reliability
If the cryocooler increases cooling capacity during gate valve closure, then temperature overshoot is prevented, but energy consumption increases unnecessarily
Solution Approach 1:
The system dynamically adjusts cooling capacity based on operational requirements. During gate valve closure, the cryocooler operates at reduced capacity (first operation mode) to conserve energy since no gas is flowing. During gate valve opening, it switches to high capacity (second operation mode) to handle the gas load and maintain temperature stability, thus optimizing the balance between reliability and energy efficiency.
Solution Approach 2:
The controller changes the operating parameters of the cryocooler based on gate valve state. When the gate valve is closed, the cryocooler operates at lower power consumption parameters. When the gate valve opens, the parameters are adjusted to increase cooling capacity, ensuring reliable vacuum performance only when needed.
3Temperature
If the cryocooler operates at high cooling capacity continuously, then temperature control is maintained, but the system response time during regeneration increases
Solution Approach 1:
The cryocooler operates periodically in two states: during regeneration, it operates at reduced capacity to allow faster warm-up and regeneration completion; during active pumping with gate valve open, it switches to high capacity to maintain temperature control. This periodic adjustment of cooling capacity optimizes both temperature control and regeneration speed.
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 cryopanel temperature overshoot during crossover events, ensuring consistent vacuum process performance and reducing the need for safety alerts and delays by maintaining the cryopanel temperature within the allowable range.
Implementation Method 1
A cryopump is a vacuum pump that captures gas molecules on a cryopanel cooled to a cryogenic temperature by condensation or adsorption
Implementation Method 2
A cryopump is a vacuum pump that captures gas molecules on a cryopanel cooled to a cryogenic temperature by condensation or adsorption
Data Source
AI summary
A cryopump capable of being mounted on a vacuum chamber via a gate valve, the cryopump includes a cryocooler, and a controller configured to detect whether or not the gate valve is closed, and to control the cryocooler such that a cooling capacity of the cryocooler when the gate valve is closed is increased compared to a cooling capacity of the cryocooler when the gate valve is opened.