MAGNETIC DISK DEVICE

PURPOSE:To attain efficient cooling with energy saving by checking the operation state of a head disk assembly (HDA) by a discriminator detecting whether the assembly is in operation or not and by a temperature detector detecting temperature and regulating a control value in response to the detection signal. CONSTITUTION:A liquid refrigerant flows to a pipe 6, a detector (discriminator) 12-1 detects that the HDA 3-1 is stopped and a controller 13 outputs a control signal closing an expansion value 7-1 and no refrigerant flows to a path 4-1 of the HDA 3-1. Detectors (discriminators) 12-2- 12-4 detect that HDAs 3-2-3-4 are in operation, a control signal opening expansion values 7-2-7-4 is outputted from the controller 13 and the refrigerant flows to paths 4-2-4-4 of the HDAs 3-2-3-4. In this case, the refrigerant is transformed into gas/liquid 2-phas flow at low temperature and low pressure by the expansion valve, the coolant flows to each path to cool the heat in the HDAs, the refrigerant is vaporized while being gradually evaporated to gas refrigerant at low temperature and low pressure.