Blower fan features

Last time we introduced Centrifugal Fan. Next we will explain about blower fans.

Blower fan structure

A blower fan is structurally similar to Centrifugal Fan. Like Centrifugal Fan, it rotates an impeller to draw in air from an opening at the front and expel it from the side. The big difference is that the impeller is covered by an ammonite-shaped case, which has an exhaust port in one location. As the impeller rotates, the air coming out radially flows along the inside of the case and is expelled from the exhaust port.

▲Figure 1: Blower fan structure

Blower fan characteristics

Blower fans provide higher static pressure than axial fans of equivalent size or Centrifugal Fan by allowing air to flow along the inside of the case. On the other hand, they tend to produce less airflow. Also, the impeller has many smaller blades than Centrifugal Fan, which is also shaped to obtain higher static pressure.
The blower P-Q performance is similar to Centrifugal Fan as shown in Figure 2, with no swirl stall region, and the shape of P-Q performance is similar to that of . Power consumption does not increase or decrease with airflow as in axial fans and Centrifugal Fan, but tends to decrease as airflow decreases and static pressure increases. Therefore, the blower generally consumes the most power at maximum airflow. Sound pressure levels tend to be quietest in the middle of the P-Q performance range.

How to use a blower fan smartly

ブロアはP-Q特性に旋回失速領域が無いので，通風抵抗との動作点位置についても制限が無く使用推奨範囲が広いです。音圧レベルはP-Q特性の中心あたりでもっとも静かになるため，装置の低騒音化にはこの付近で動作させることがポイントです。
ブロアはファンのなかで高い静圧を得やすいという特長があります。そのため，部品が密集した通風抵抗が高い装置での使用に適しています。また，1ヵ所から空気が吐き出されるため，風を直接当てて局所的に冷却する用途にも適しています。

Supervised by: SANYO DENKI CO., LTD. Cooling System Design Department

release date: 2021-01-22 00:00