Patent ID: 7351031

Claim:
A centrifugal blower comprising: a housing comprising a compartment delimited by an annular wall, a radial air inlet being defined in the annular wall and communicated with the compartment, the compartment including an axial opening; an impeller rotatably mounted in the compartment, the impeller including a hub and a plurality of blades; and a guide cover mounted on top edges of the blades, the guiding cover including an axial air inlet in a central portion thereof and an outer end extending radially outward, the guiding cover covering the axial opening of the compartment without in contact with the housing, the outer end of the guiding cover covering a top of the axial opening of the compartment without being in contact with the housing, thereby maintaining wind pressure in the compartment; the blades and the guiding cover turning synchronously when the impeller turns, airflow being driven by the blades and guided by the guiding cover and exiting the housing via the radial air outlet.