"Micro Cooling Fan" scroll effect is to bring together the impeller exit gas stream and are directed to the blower outlet, while the part of the flow kinetic energy into pressure energy. Volute shape logarithmic spiral or Archimedean spiral best, with the highest efficiency. Volute axial plane is rectangular, and the width unchanged. Flow velocity at the outlet of the volute is still large, in order to effectively utilize the energy stream, the "Micro Cooling Fan" volute diffuser outlet means, the outlet gas stream due to scroll by the inertia effect of the impeller rotation direction skewed, so diffuser Usually made to expand along the oblique direction, the diffusion angle is typically 6 to 8, centrifugal fan volute exit site have tongue structure, generally referred to as vortex tongue. "Micro Cooling Fan" vortex tongue can prevent the gas circulating within the housing. Generally vortex fan efficiency tongue, tongue pressure than those without fans.