Rotary Valve Mechanism for Cryocooler Load Torque Reduction
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Solution Overview
Problem
Existing cryocoolers face challenges in increasing cooling capacity without proportionally increasing the size of the drive motor, particularly due to the need for larger expansion chambers and the resulting larger displacers and cylinders.
Innovation Solution
The implementation of a rotary valve mechanism with a valve rotor and stator design that includes communication grooves and recessed portions, allowing for controlled fluid communication and reduced pressure peaks, thereby minimizing the load torque on the motor and preventing the need for a larger motor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the expansion chamber size is increased to enhance cooling capacity, then the cooling capacity is improved, but the displacer and cylinder sizes must also increase, leading to larger overall system dimensions
Solution Approach 1:
The patent changes the pressure parameters within the expansion chamber by introducing a low-pressure region and controlling pressure distribution through the valve mechanism. This allows the same chamber volume to produce greater cooling effect by optimizing the pressure differential across the displacer, thereby improving cooling capacity without increasing chamber size.
Solution Approach 2:
The patent employs a dynamic valve mechanism that rotates to alternately connect high-pressure and low-pressure gas sources to different regions of the expansion chamber. This dynamic control of pressure distribution enables the system to maximize cooling capacity within a fixed chamber volume by creating optimal pressure differentials during different phases of the cycle.
2Productivity
If the displacer size is increased to accommodate larger expansion chamber, then the cooling capacity is improved, but the load torque on the motor increases, requiring a larger motor size
Solution Approach 1:
The patent changes the pressure parameters within the expansion chamber by introducing a low-pressure region and controlling pressure distribution through the valve mechanism. This allows the same chamber volume to produce greater cooling effect by optimizing the pressure differential across the displacer, thereby improving cooling capacity without increasing chamber size.
Solution Approach 2:
The patent employs a dynamic valve mechanism that rotates to alternately connect high-pressure and low-pressure gas sources to different regions of the expansion chamber. This dynamic control of pressure distribution enables the system to maximize cooling capacity within a fixed chamber volume by creating optimal pressure differentials during different phases of the cycle.
3Productivity
If the cylinder size is increased to accommodate larger displacer, then the cooling capacity is improved, but the overall system dimensions increase, reducing system compactness
Solution Approach 1:
The patent changes the pressure parameters within the expansion chamber by introducing a low-pressure region and controlling pressure distribution through the valve mechanism. This allows the same chamber volume to produce greater cooling effect by optimizing the pressure differential across the displacer, thereby improving cooling capacity without increasing chamber size.
Solution Approach 2:
The patent employs a dynamic valve mechanism that rotates to alternately connect high-pressure and low-pressure gas sources to different regions of the expansion chamber. This dynamic control of pressure distribution enables the system to maximize cooling capacity within a fixed chamber volume by creating optimal pressure differentials during different phases of the cycle.
4Device complexity
If a conventional valve mechanism is used to control pressure, then the system structure is simple, but pressure peaks occur during operation, increasing load torque on the motor
Solution Approach 1:
The patent employs a dynamic valve mechanism that rotates to alternately connect high-pressure and low-pressure gas sources to different regions of the expansion chamber. This dynamic control of pressure distribution enables the system to maximize cooling capacity within a fixed chamber volume by creating optimal pressure differentials during different phases of the cycle.
Solution Approach 2:
The patent introduces a low-pressure gas source that connects to the expansion chamber before the high-pressure gas injection. This preliminary creation of a low-pressure region prepares the chamber to receive high-pressure gas more efficiently, reducing pressure peaks and the resulting load torque on the motor during the high-pressure gas injection phase.
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 enhances the cooling capacity of cryocoolers by reducing the load torque on the motor, enabling the use of a smaller motor size while maintaining efficient operation, thus preventing an increase in motor size and improving overall system efficiency.
Implementation Method 1
a valve rotor which includes a rotor plane which is perpendicular to a valve rotation axis and is in surface-contact with the stator plane, a rotor recessed portion which is open to the rotor plane and communicates with the high-pressure gas inflow port, and a first rotor communication path which is open to the rotor plane and extends toward the rotor recessed portion, the valve rotor being disposed in the low-pressure gas chamber so as to rotate around the valve rotation axis with respect to the valve stator
Implementation Method 2
The expander can generate coldness by appropriately synchronizing a volume change and a pressure change of the expansion chamber
Implementation Method 3
a displacer which is engaged to the motor so as to be reciprocated by the motor
Data Source
AI summary
A rotary valve mechanism of a cryocooler includes a valve rotor and a valve stator. A rotor recessed portion is formed such that the rotor recessed portion fluidally communicates with a stator recessed portion at a first opening degree at a second phase of a valve rotation. The valve rotor includes a first rotor communication groove and/or a second rotor communication groove formed in the valve rotor such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at a first phase preceding the second phase, and/or the valve stator includes a stator communication path formed in the valve stator such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at the first phase preceding the second phase.