IMPROVEMENT OF COOLING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a temperature control system for cooling a magnetic element of an MRI(magnetic resonance imaging) instrument. SOLUTION: This control system is provided with wax 16, which is substantially retained at a phase transition temperature between a solid and liquid, but substantially retains a solid state and is in a contact relation with the magnetic element 14. A sensor 18 is dipped in the wax 16 and provides a signal expressing the state transition of the wax 16. The sensor 18 is connected to a controller 20, and the controller controls the operation of a heating element 26 dipped in the wax 16 so as to adjust its temperature. In the operation of the MRI, the wax 16 is changed into liquid by using the heat generated by the magnetic element 14, the sensor 18 senses the change and transmits a signal to the controller 20, and the controller turns off the heating element 26. When the sensor 18 detects the wax 16 substantially returned to its solid state, the controller turns on the heating element 26 so as to retain the wax 16 in the phase transition temperature but in the substantially solid state.