Patent ID: 7724515

Claim:
A disk array apparatus, comprising: a disk array and a controller thereof; a first fan unit including a plurality of fans in an upper part of the disk array apparatus, the plurality of fans being arranged in a horizontal direction in the first fan unit; an exhaust duct unit having an exhaust structure and an exhaust port for exhaust to an outside from the first fan unit; and a cooling air flow path for air flow extending from a lower part of the disk array apparatus through which air is taken in from the outside via operation of the first fan unit, through the disk array apparatus, and through the fans of the first fan unit to the outside through the exhaust duct unit, wherein the exhaust structure of the exhaust duct unit is divided into a plurality of exhaust flow paths extending from the plurality of fans of the first fan unit to the exhaust port by a plurality of partition plates being arranged in accordance with the fans of the first fan unit such that a respective pair of exhaust flow paths of the plurality of exhaust flow paths is associated with each pair of fans of the plurality of fans of the first fan unit, and wherein a difference in flow path length between a first exhaust flow path and a second exhaust flow path of each pair of exhaust flow paths is equivalent to a half wavelength of a specific frequency of noise generated by air flow passing along the cooling air flow path through the first fan unit such that a first sound of the specific frequency generated by the first fan unit is synthesized by a second sound of a phase that is inverted to that of the first sound produced by air flow passing along the cooling air flow path through the exhaust structure to reduce the noise generated by air flow passing along the cooling air flow path through the first fan unit.