Cooling apparatus

Abstract

Described herein is a temperature control system for cooling magnetic elements (14) in MRI apparatus (10). The control system comprises a wax (16) in contact with the elements (14) which is substantially maintained at its phase transition temperature between a solid state and a liquid state, but in a substantially solid state. A sensor (18) is immersed in the wax (16) and operates to provide a signal on the change of state of the wax (16). The sensor (18) is connected to a controller (20) which controls the operation of a heating element (26) also immersed in the wax (16) to control the temperature thereof. When the MRI apparatus is operational, heat is generated by the magnetic elements (14) is used to change the wax (16) to a liquid, this change being detected by the sensor (18) which sends signals to the controller (20) to turn off the heating element (26). Once, the sensor (18) detects that the wax (16) has reverted to a substantially solid state, the controller (20) turns the heating element (26) on to maintain the wax (16) at its phase transition temperature but in a substantially solid form.

Dependencies are inferred from the claim text.