MRI Radiation Shield Cooling With Mode-Switched Gas Routing
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Solution Overview
Problem
The efficiency of cooling the radiation shield in magnetic resonance imaging apparatuses using superconducting magnets is inadequate during certain operations, leading to temperature fluctuations that degrade image quality, and existing systems fail to optimally manage refrigerant discharge and heat exchange.
Innovation Solution
A system with multiple pipes and valves is implemented to control the flow of refrigerant gas, allowing for efficient heat exchange with the radiation shield by routing the gas through different paths based on operational needs, thereby optimizing cooling efficiency and maintaining temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single pipe configuration is used for refrigerant discharge, then the device complexity is low, but the cooling efficiency cannot be optimized for different operational modes
Solution Approach 1:
The single pipe is divided into multiple separate pipes (first pipe for initial cooling, second pipe for quenching, third pipe for refrigeration machine stop) with dedicated functions. This segmentation allows each pipe to be optimized for its specific operational mode while maintaining overall system versatility through the switching assembly that selects appropriate pipes based on operational requirements.
Solution Approach 2:
The system employs a switching assembly that dynamically selects which pipe to open based on the current operational mode (initial cooling, quenching, refrigeration machine stop, or normal operation). This dynamic configuration allows the system to adapt the refrigerant discharge path in real-time, optimizing cooling efficiency for each mode without requiring all pipes to be permanently open or complex multi-valve arrangements.
2Temperature
If refrigerant gas is continuously discharged to cool the radiation shield, then the cooling efficiency is high, but the temperature stability deteriorates due to excessive cooling during certain operations
Solution Approach 1:
Different pipes are designed with different discharge characteristics suited to different operational modes. The first pipe has characteristics optimized for initial cooling, the second for quenching, and the third for refrigeration machine stop conditions. Each pipe's local characteristics (discharge rate, flow path) are tailored to the specific cooling needs of that operational mode, preventing excessive cooling during normal operation while maintaining high cooling efficiency when needed.
Solution Approach 2:
The system changes the refrigerant discharge parameters (flow rate, discharge path) based on operational mode by selecting different pipes through the switching assembly. During initial cooling, quenching, or refrigeration machine stop, the system opens appropriate pipes to increase cooling capacity. During normal operation, the system maintains different discharge parameters to prevent excessive cooling and maintain temperature stability.
3Adaptability or versatility
If multiple pipes are used to optimize cooling for different modes, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The switching assembly serves multiple functions: it selects which pipe to open based on operational mode, controls refrigerant discharge timing, and coordinates with the refrigeration machine operation. This multi-functionality reduces the need for separate control mechanisms for each pipe, thereby limiting the increase in device complexity while maintaining high operational mode adaptability.
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 system effectively maintains the radiation shield's temperature within a stable range, reducing the time to reach steady state and preventing excessive temperature fluctuations, thus enhancing image quality and operational efficiency.
Implementation Method 1
routing the gas through different paths based on operational needs, thereby optimizing cooling efficiency and maintaining temperature stability
Implementation Method 2
control the flow of refrigerant gas, allowing for efficient heat exchange with the radiation shield
Implementation Method 3
efficient heat exchange with the radiation shield
Implementation Method 4
A magnetic resonance imaging apparatus includes a superconducting magnet that can generate a magnetic force stronger than a magnetic force generated by a normal electromagnet
Implementation Method 5
a pipe for discharging evaporated refrigerant to the outside is arranged in the radiation shield
Implementation Method 6
evaporated refrigerant may be temporarily released into the outside air when initial cooling is performed
Data Source
AI summary
A magnetic resonance imaging apparatus according to an exemplary embodiment includes a superconducting coil, a first container, a radiation shield, a second container, first to third pipes, and a switching assembly. The first container houses the superconducting coil which is immersed in refrigerant liquid, and also contains refrigerant gas generated by vaporization of the refrigerant liquid. The radiation shield houses the first container. The second container houses the radiation shield. The first pipe directs the refrigerant gas in the first container into an outside of the radiation shield. The second pipe allows the refrigerant gas from the first pipe, to pass through so as to enable the refrigerant gas to exchange heat with the radiation shield. The third pipe discharges the refrigerant gas from the first pipe, to an outside. The switching assembly directs the refrigerant gas from the first pipe, into the second pipe or the third pipe.