Gas filtering arrangement for magnetic disk information storage apparatus

Magnetic disk information storage apparatus of the kind employing heads flying in a gaseous medium adjacent a magnetic disk and comprising:

• at least one magnetic disk;
• at least one magnetic head for transducing signals representative of information onto or from said disk;
• a housing substantially enclosing and sealing said at least one disk and said at least one head, and comprising first and second end walls spaced axially from said disk on opposite sides thereof and a side wall surrounding said disk;
• a spindle supporting and being rigidly connected to said at least one disk and having one free end within said housing and a second end external to said housing;
• a bearing located in said first wall of said housing and supporting said spindle for rotation about an axis thereof, said bearing constituting a path for gas leakage between the interior and exterior of said housing;
• an impeller mounted on said free end of said spindle for rotation therewith;
• a main filter within said housing for filtering said gaseous medium;
• means for supporting said main filter in a position spaced from and between said impeller and said second wall of said housing;
• and means for rotating said spindle thereby developing a pressure distribution within said housing with which is characterized by a region of relatively lower pressure in the vicinity of said impeller and a region of relatively higher pressure in the vicinty of said bearing;
• said apparatus further comprising
• breather filter means having at least one external gas port to the exterior of said housing and having an internal gas port to the interior of said housing, said internal gas port being located in said relatively low pressure region whereby the pressure in said region is substantially equalized with the ambient pressure exterior to said housing and the pressure in the vicinity of said bearing is above ambient pressure so as to reduce the likelihood of contaminants entering the storage apparatus.