Cryocooler
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Solution Overview
Problem
Large cryocoolers require significant flow rate adjusting devices to manage pressure and cooling capacity, leading to increased size and power consumption, particularly when using single electric valves for bypass line control.
Innovation Solution
A cryocooler design incorporating a bypass line with both a variable flow rate bypass using a flow rate control valve and a fixed flow rate bypass using an on/off valve, allowing for precise and approximate flow rate control through a combination of opening degree adjustments and switching, to manage pressure and cooling capacity without enlarging the flow rate adjusting device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electric valve is used for bypass line control to manage pressure and cooling capacity, then the control function is simplified, but the device size and power consumption increase significantly
Solution Approach 1:
The bypass line flow rate control is segmented into two independent bypasses: a variable flow rate bypass with a flow rate control valve for continuous adjustment, and a fixed flow rate bypass with an on/off valve for discrete flow rate levels. This segmentation allows the system to achieve comprehensive flow rate control while using smaller, more efficient valves in each bypass, thereby reducing the overall device size and power consumption compared to using a single large electric valve.
2Device complexity
If a single electric valve is used for bypass line control to manage pressure and cooling capacity, then the control function is simplified, but the power consumption increases
Solution Approach 1:
The control system is segmented into two independent valve control circuits: one for the variable flow rate bypass and another for the fixed flow rate bypass. Each bypass handles a portion of the total flow rate control requirement, allowing the use of smaller, lower-power valves. The flow rate control unit can independently control each bypass, optimizing power consumption by activating only the necessary bypass based on the required cooling capacity and pressure conditions.
3Device complexity
If a single electric valve is used for bypass line control, then the system structure is simplified, but the device size increases
Solution Approach 1:
The bypass line is divided into multiple parallel bypasses (variable flow rate bypass and fixed flow rate bypass), each equipped with its own valve. This segmentation allows the system to distribute the flow rate control function across multiple smaller components rather than relying on a single large valve, thereby reducing the overall device volume while maintaining comprehensive control capability.
4Device complexity
If a single electric valve is used for bypass line control, then the control mechanism is simplified, but the precision of flow rate control decreases
Solution Approach 1:
The flow rate control is segmented into continuous control (variable flow rate bypass with flow rate control valve) and discrete control (fixed flow rate bypass with on/off valve). This segmented approach provides multiple control levels and modes, allowing the system to achieve high precision flow rate control by combining the fine adjustment capability of the variable bypass with the stable flow rate levels of the fixed bypass, thereby improving overall control precision compared to a single valve system.
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 design allows for efficient pressure control and reduced size of the flow rate adjusting device, enabling effective management of cooling capacity while minimizing power consumption and device size, even in large cryocoolers.
Implementation Method 1
The working gas is expanded by the expander to generate cold. The expansion reduces a pressure of the working gas.
Implementation Method 2
The variable flow rate bypass 27 includes a flow rate control valve 30...The flow rate control unit 52 controls a flow rate of the working gas flowing in the bypass line 24 through a combination of opening degree adjustment of the flow rate control valve 30
Implementation Method 3
The fixed flow rate bypass 28 includes an on/off valve 32...through a combination of opening degree adjustment of the flow rate control valve 30 and switching of the on/off valve 32
Implementation Method 4
The compressor 12 compresses a working gas of the cryocooler 10 at a high pressure and supplies the working gas to the expander 14.
Data Source
AI summary
A cryocooler includes a compressor, an expander, a gas line that allows a working gas to be circulated between the compressor and the expander and includes a high pressure line through which the working gas is supplied from the compressor to the expander and a low pressure line through which the working gas is collected from the expander to the compressor, a bypass line that connects the high pressure line to the low pressure line such that the working gas bypasses the expander and returns from the high pressure line to the low pressure line, and a bypass flow rate control unit that controls a flow rate of the working gas flowing in the bypass line to provide pressure control of the gas line. The bypass line includes a variable flow rate bypass and a fixed flow rate bypass.