Abstract: A laminar flow fan is adapted to fit into a the internal cavity of a fan housing (70). The fan comprises a stack of parallel disk elements (12, 14, 16, 18, 20, 22) mounted for rotation on a motor (40) with the diameters of the disk elements varying within the stack to more fully utilize the available internal space of the housing. Apparatus which uses such a fan as part of its forced air cooling system is also described.

Abstract: Electrical apparatus is described which may include one or more electrical devices, each being located in a corresponding one of a plurality of device positions defined in a first section of a housing. The system further includes at least one dual side entry brushless dc motor driven centrifugal fan positioned such that each side entry is opposite a device position, and a power supply unit. In operation, the fans provide forced air cooling of the devices and power supply. Each of the devices is selected from a plurality of possible device types, each device type presenting a different impedance to the flow of cooling air.

Abstract: A multimedia data storage system including a compartmentalized drawer which can be tailored to accommodate the differing cooling requirements of different device types thus allowing each device type to be mounted in any device position. A cover in the form of a frame having a plurality of openings fits onto the front of the drawer. A first device type includes a front bezel which fills one opening in the cover and is cooled by air passing through a number of holes located along the length of the lower surface of the frame. A second device type is cooled by air passing through a number of holes located along the length of the lower surface of the frame. A second device type is cooled by air passing through a louvred panel located in one opening in the cover. The panel includes a blanking member which blocks off the frame cooling holes located in front of the second device type. Thus, for this device type, there is no air flow through the cooling holes.

Abstract: A centrifugal fan includes a brushless d.c. motor, an impeller mounted on the motor and a scroll on which the motor is mounted. The scroll defines the air inlet and outlet and has an outer wall curved around the impeller to define a divergent air flow path. By truncating the scroll at the outlet substantially to eliminate any flat portions on the outer wall susceptible to mechanical vibrations at frequencies excited by the d.c. motor, a noise reduction is achieved. Further noise reduction may be achieved by resiliently mounting the motor on the scroll.

Abstract: A disk file 10 employs at least two filters 15,16 for removal of airborne particles, one filter 16 having a relatively coarse mesh and a relatively high rate of airflow and the other 15 having a relatively fine mesh and a relatively low rate of airflow. The fine filter 15 may be combined with a third, breather filter 30 which removes particles from air entering the disk enclosure. The main purpose of the coarse filter 16 is to remove the larger, more damaging particles very rapidly, thereby reducing the risk of damage to the surfaces of the disks 12.

Abstract: Relative humidity within a machine enclosure is controlled by means of a desiccant and a circulatory breather flow through the enclosure walls. The desiccant absorbs moisture during power off periods to keep the relative humidity down. During power on periods the enclosure temperature rises, which drives off the absorbed moisture from the desiccant. Operation of the machine also creates a pressure differential between two breather orifices in the enclosure walls so that there is a circulatory exchange of air between the enclosure and atmosphere. If the desiccant has absorbed a significant amount of moisture during power off periods, the moisture concentration within the enclosure will exceed that outside and there will be a net expulsion of moisture to partially recharge the desiccant.