Fan Dampers of Centrifugal Fan

Abstract

A centrifugal fan is provided with an electric motor; an impeller driven by the electric motor; and fan dampers around an inner surface of fan housing and surrounding the impeller. Each fan damper has a windward, concave surface facing a rotational direction of the impeller. A spiral airflow created by the impeller passes the windward curved portions of the fan dampers and the motor toward an outlet. A portion of the kinetic energy of the spiral airflow is transmitted axially and the remaining kinetic energy of the spiral airflow is converted into static pressure to convey the spiral airflow toward the outlet so as to converge the spiral airflow from the electric motor to the outlet, thereby causing most of the spiral airflow to flow axially when it reaches the outlet.

What is claimed is: 
     
         1 . A centrifugal fan comprising:
 an inlet housing including an axial inlet;   an outlet housing including an axial outlet, the outlet housing being secured to the outlet housing to define an interior;   an electric motor disposed in the interior;   an impeller disposed in the interior and driven by the electric motor; and   a plurality of fan dampers disposed around an inner surface of the interior and surrounding the impeller, each of the fan dampers having a windward, concave surface facing a rotational direction of the impeller;   wherein a spiral airflow created by the impeller passes the windward curved portions of the fan dampers and the motor toward the outlet, and wherein a portion of the kinetic energy of the spiral airflow is transmitted axially and the remaining kinetic energy of the spiral airflow is converted into static pressure to convey the spiral airflow toward the outlet so as to converge the spiral airflow from the electric motor to the outlet, thereby causing most of the spiral airflow to flow axially when it reaches the outlet.   
     
     
         2 . The centrifugal fan of  claim 1 , wherein the fan dampers are formed integrally with the inlet housing or the outlet housing. 
     
     
         3 . The centrifugal fan of  claim 1 , wherein the fan dampers are manufactured separately prior to securing to an inner surface of the inlet housing or the outlet housing. 
     
     
         4 . The centrifugal fan of  claim 1 , wherein each of the fan damper has a windward end and a leeward end, wherein the impeller has a disc, wherein the windward end is at angle of 0-45 degrees with respect to the disc with the angle being increased axially, and wherein the leeward end is at angle of 70-90 degrees with respect to the disc. 
     
     
         5 . A centrifugal fan comprising:
 a fan housing;   an impeller disposed in a forward end of the fan housing;   a starter motor disposed adjacent to the impeller in the fan housing;   a combustion chamber disposed in an intermediate portion of the fan housing;   a turbine disposed in a rear end of the fan housing; and   a plurality of fan dampers disposed proximate to an inner surface of the fan housing and around the impeller, each of the fan dampers having a windward, concave surface facing a rotational direction of the impeller;   wherein a spiral airflow created by the impeller passes the windward curved portions of the fan dampers toward the combustion chamber, wherein a portion of the kinetic energy of the spiral airflow is transmitted axially and the remaining kinetic energy of the spiral airflow is converted into static pressure to convey the spiral airflow toward the combustion chamber, wherein fuel is injected into the combustion chamber to mix with air prior to combustion, and wherein the combusted mixture rotates the turbine to generate mechanical energy.