The way that counter rotating local fan with the characteristics of high efficency, low noise, high pressure and large flow rate is not practical is put forward.
提出 对旋式局部通风机具有高效率、低噪声、高风压、大风量性能特性的说法是不符合实际的宣传。
2
The recuperators have high air resistance , low air preheating temperature and high fanpressure head , and fan has much noise to environment and are apt to break down with vibration .
此换热器空气阻力大，空气预热温度不高，风机压头高，环境噪声大，风机振动大、易损坏。
3
A new structure fan with small size, high pressure and low flow-rate is designed to meet the demands of industry.