Disk Drive Pressure-Controlled Particle Count and Filter Test Method
Original Publication Date: 1988-Nov-01
Included in the Prior Art Database: 2005-Feb-15
This method allows a file to be particle counted, while maintaining the file at its normal internal operating pressure, and simultaneously checks the integrity of the breather filter. The pressure sensor 1, via the pressure sense line 2, measures pressure inside the disk drive file 3 via the file PC port 4 and particle count tube 6. As sample air is removed form the disk drive file 3, pressure inside the file decreases due to the pressure drop across the atmospheric breather filter 7. When the pressure inside the file goes negative as compared to the preset value stored in the pressure sensor 1, the pressure sensor 1 sends a proportional voltage signal 8 to the flow controller 9. The flow controller 9 increases the air flowing through the make-up air line 10 to the disk drive file 3.