Blower having a blower tube incorporating a reduction device for reducing the clear flow cross section of said blower tube at idle operation

A blower comprising:

• a housing;
• a single blower pipe connected to said housing;
• an internal combustion engine for providing an adjustable power output and said engine being located within said housing;
• a blower wheel driven by said engine for generating an air flow in said blower pipe;
• a reduction device mounted in said air flow downstream of said blower wheel for changing the clear flow cross section of said blower pipe in dependence upon the adjusted power output of said engine so as to reduce said clear flow cross section during idle operation of said engine;
• said reduction device including a throttle flap pivotally mounted and eccentrically journalled in said air flow downstream of said blower wheel;
• and,
• resilient biasing means for applying a resilient biasing force to said throttle flap sufficient to overcome the force of said air flow when said engine is in said idle operation to thereby automatically effect a reduction of said clear flow cross section at said idle operation and thereby reducing the engine power required to move the air flow, said eccentrically journalled throttle flap and resilient biasing means being adapted in a way, that during full load operation, as a result of the dynamic pressure of the air flow applied to the throttle flap, said flap is in its open position.