Cryocooler
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Solution Overview
Problem
Cryocoolers with multiple compressors connected in parallel face issues with backflow of working gas when one compressor stops, which can degrade cooling performance and increase manufacturing costs due to the need for additional components like check valves to prevent backflow.
Innovation Solution
Implementing a system with state detection sensors and a compressor control unit that synchronously stop all compressor main bodies when any one compressor is detected as stopped, eliminating the need for backflow countermeasures like check valves by managing the operation of multiple compressors to prevent backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If check valves are added to prevent backflow, then backflow is prevented, but manufacturing costs increase and cooling performance decreases due to pressure loss
Solution Approach 1:
The patent replaces the mechanical backflow prevention system (check valves) with a control system that uses sensors to detect compressor stoppage and electronically controls the contactors to prevent backflow. The control unit receives stoppage detection signals and opens the contactor for the stopped compressor while closing contactors for operating compressors, eliminating the need for mechanical check valves.
Solution Approach 2:
The patent introduces a control unit as an intermediary between the compressors and the power supply. This control unit mediates the operation by detecting compressor stoppage and controlling the contactors to prevent backflow, serving as a smart intermediary that replaces the need for passive mechanical check valves in each compressor line.
2Reliability
If check valves are added to prevent backflow, then backflow is prevented, but cooling performance decreases due to pressure loss
Solution Approach 1:
The patent replaces the mechanical check valves that cause pressure loss with an electronic control system using contactors. By opening the contactor for stopped compressors and closing contactors for operating compressors, the system prevents backflow without the continuous pressure drop that would occur through check valves, thereby maintaining cooling performance.
3Productivity
If multiple compressors operate in parallel, then cooling capacity increases, but backflow occurs when one compressor stops
Solution Approach 1:
The patent implements a feedback control system where stoppage detection sensors continuously monitor compressor operation and provide feedback to the control unit. When a compressor stops, the sensor detects it and sends a signal to the control unit, which then adjusts the contactor states to prevent backflow, creating a closed-loop feedback mechanism that maintains system reliability.
Solution Approach 2:
The patent makes the compressor system dynamic by enabling individual compressors to be independently controlled through contactors. Instead of all compressors operating rigidly in parallel, the system dynamically adjusts which compressors are active based on real-time conditions, allowing one compressor to stop while others continue operating without causing backflow.
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 effectively mitigates backflow without reducing cooling performance and avoids the increased manufacturing costs associated with adding countermeasures, ensuring reliable operation and cost-effectiveness.
Implementation Method 1
a plurality of state detection sensors that are provided to correspond to the plurality of compressor main bodies respectively and each detect a state of a corresponding compressor main body to output a state detection signal
Implementation Method 2
a compressor control unit that is configured to, in a case where the state detection signal from any one state detection sensor of the plurality of state detection sensors indicates that the corresponding compressor main body is stopped, stop also the other compressor main bodies
Implementation Method 3
The compressor compresses a working gas of the cryocooler to a high pressure and supplies the working gas to the expander
Implementation Method 4
The working gas is expanded by the expander to generate cold. The expansion decreases a pressure of the working gas
Data Source
AI summary
A cryocooler includes a cold head, a plurality of compressor main bodies that are connected to the cold head in parallel, a plurality of state detection sensors that are provided to correspond to the plurality of compressor main bodies respectively and each detect a state of a corresponding compressor main body to output a state detection signal, and a compressor control unit that is configured to, in a case where the state detection signal from any one state detection sensor of the plurality of state detection sensors indicates that the corresponding compressor main body is stopped, stop also the other compressor main bodies.