Overview

    after repeated experiments and research, SDF(D) energy saving four-stage counter rotating axial flow fans for long and large tunnels are fans especially designed for long and large tunnels, and have got national patents. They are applicable to the long distance and constant air volume ventilation of tunneling construction of highway, railway and diversion works, and have the characteristics of long air delivery distance, low noise, high efficiency and large air volume, thus they solve the problem that ordinary axial flow fans cannot meet air delivery demand when tunneling distance is long.

SDF(D) energy saving four-stage counter rotating axial flow fans for long and large tunnels are applicable to the ventilation requirement under plateau environment.for construction ventilation under special environment, various spraying treatments of blades could also be made according to the requirements of users.

Each stage of SDF(D) energy saving four-stage counter rotating axial flow fans for long and large tunnels is driven by the same power motor. Impeller and motor are directly connected and the rotation between adjacent impellers is in opposite direction. Air flow could get energy after entering to primary impeller, accelerate through secondary impeller and then accelerate the removal after the last impeller. The last impeller plays the function of static guide vane in ordinary axial flow fan, which increases the energy of air flow while getting the velocity component in straightening circumference direction, and then reach the higher air pressure and efficiency than that of two-stage counter rotating fans.

4.2 Characteristics

Characteristics are long air delivery distance, high efficiency, low noise, high air pressure, large air volume, constant air volume and energy saving. Either single-stage or double-stage or three-stage could be opened for operation according to ventilation requirements. The energy saving effect is obvious.