Cryocooler High-Pressure Line Volume Control to Shorten Cooldown Time
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Solution Overview
Problem
Cryocoolers require extended cooldown times to reach cryogenic temperatures, which hinders the efficient cooling of target objects such as superconducting devices.
Innovation Solution
The method involves increasing the volume of the high pressure line during cooldown, controlling the compressor operation frequency based on pressure or differential pressure, and then decreasing the volume once the cryogenic temperature is reached to maintain the cold head at that temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the volume of the high pressure line is increased during cooldown, then the cooldown time is shortened, but the device complexity increases due to the buffer volume component
Solution Approach 1:
The high pressure line is segmented into two functional sections: a main high pressure line for normal operation and a buffer volume for cooldown enhancement. This segmentation allows the buffer volume to be selectively connected during cooldown and disconnected during normal operation, reducing its impact on overall device complexity while maximizing its benefit for shortening cooldown time.
Solution Approach 2:
The buffer volume is pre-connected to the high pressure line before the cooldown process begins. This preliminary action ensures that the additional volume is immediately available to store refrigerant gas and accelerate the cooldown process from the start, rather than needing to be added dynamically during the cooling process.
2Productivity
If the operation frequency of the compressor is controlled based on pressure, then the cooling efficiency is improved, but the control system complexity increases
Solution Approach 1:
The compressor operation frequency is controlled based on real-time pressure feedback from the high pressure line. The control system continuously monitors the pressure and adjusts the compressor frequency accordingly, creating a closed-loop feedback system that optimizes cooling efficiency while maintaining relatively simple control logic.
Solution Approach 2:
The system uses its own operational parameters (pressure in the high pressure line) to automatically regulate its performance (compressor frequency). This self-service approach allows the system to optimize its own cooling efficiency without requiring complex external control systems or multiple sensors.
3Temperature
If the volume of the high pressure line is decreased after cooldown, then the cold head is maintained at cryogenic temperature, but the device complexity increases due to the switching mechanism
Solution Approach 1:
The volume of the high pressure line is made dynamic rather than static. The buffer volume is connected during cooldown to accelerate cooling, then disconnected during normal operation to maintain optimal system performance. This dynamic reconfiguration allows the system to adapt its volume based on operational requirements, improving temperature stability while managing complexity through a single switching mechanism.
Solution Approach 2:
The buffer volume serves multiple functions: it accelerates cooldown when connected and is then disconnected to maintain normal operation. This multi-functionality allows a single component to address both cooldown time reduction and normal operation efficiency, reducing the need for separate systems for each function.
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 approach significantly shortens the cooldown time of the cryocooler, enhancing its cooling capacity and efficiency.
Implementation Method 1
a compressor (12)... through which a refrigerant gas is supplied from the compressor (12)
Implementation Method 2
a cold head (14)... to cool various target objects such as a superconducting device
Implementation Method 3
cooling the cold head (14) from the room temperature to a cryogenic temperature
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A starting method for a cryocooler (10) includes increasing a volume of a high pressure line (35) when a cold head (14) is at a room temperature, cooling the cold head (14) from the room temperature to a cryogenic temperature while controlling an operation frequency of a compressor (12) based on a pressure of the high pressure line (35) or a differential pressure between the high pressure line (35) and a low pressure line (36), after the volume of the high pressure line (35) is increased, decreasing the volume of the high pressure line (35) after the cold head (14) is cooled to the cryogenic temperature, and maintaining the cold head (14) at the cryogenic temperature after the volume of the high pressure line (35) is decreased.