Centrifugal blower and power working machine

A power working machine comprising a centrifugal blower, a driving source for driving said centrifugal blower, and a backpack frame having a first portion adapted to be carried on a back of a user and a second portion extending from one end of said first portion, said centrifugal blower and said driving source being mounted on said second portion of said backpack frame,

• said centrifugal blower comprising:
• an impeller having a hub plate driven by said driving source to rotate about an axis, a set of blades disposed on at least one surface of said hub plate so as to surround said axis, and an air inlet defined by inner ends of said blades, said impeller taking air into said air inlet upon rotation so as to discharge said air radially outward;
• a casing surrounding said impeller, said casing having an intake port communicating with said air inlet and having a volute portion disposed at an outer periphery thereof, said casing being mounted on said second portion of said backpack frame such that the intake port is directed to said first portion of said backpack frame;
• and
• sound absorbing means disposed at only a portion of said casing which is adjacent and opposite said set of blades and which is between said first portion of said backpack frame and said set of blades.