Patent ID: 8197198
Filing Date: 2012-06-12
Classification: F04D

Abstract:
1. A fan system, comprising: n or more axial flow fans and n-1 ducts that are alternately disposed on the same axis, where n is an integer of 2 or more, the n or more axial flow fans each comprising: the n-1 ducts each comprising: an end surface of a rear end portion of each stationary blade and an end surface of a front portion of the duct blade corresponding to the stationary blade have the same shape, and they align together and contact each other to form one composite stationary blade, with the discharge port of each axial flow fan communicating with the inlet port of the duct housing located behind the axial flow fan; each duct blade is shaped to transform a vortex flow into a substantially laminar flow without reducing a flow rate in the duct so that a substantially laminar air flow is discharged from the outlet port; the plurality of stationary blades of the axial flow fan located in front of the duct each have a rear end portion located in one direction of the axis and a front end portion located in the other direction of the axis, the front end portion being shifted with respect to the rear end portion in a direction opposite to a rotational direction of the impeller, each stationary blade being curved to form a convex surface in the rotational direction of the impeller from the motor case toward the housing body, and each stationary blade being shaped such that a cross section of the stationary blade taken in a direction perpendicular to a direction from the motor case toward the housing body is curved to form a convex surface in the rotational direction; the front portion of each duct blade is shaped such that a cross section of the duct blade is an extension of the cross section of the corresponding stationary blade as the duct blade is viewed in cross section taken in the perpendicular direction, and a rear portion of each duct blade is shaped such that a tangent plane to a surface of the rear portion located in the rotational direction includes a tangent line extending in parallel to the axis; the duct housing includes a cylindrical body coupled to the housing body of the fan housing, and a core concentrically disposed inside the cylindrical body; one end of each of the duct blades is fixed to an inner periphery of the cylindrical body and the other end of each of the duct blades is fixed to an outer periphery of the core; a length of each auxiliary duct blade in the axial direction is the same as a length of the rear portion of each duct blade in the axial direction.