I. Overview

SDF series tunnel ventilation fans are suitable for tunnel construction ventilation in highway, railway, and hydropower projects, as well as other underground engineering construction ventilation. Main products include SDF _(A) type tunnel construction dedicated contra-rotating axial flow fan, SDF _(B) type tunnel worker dedicated contra-rotating axial flow fan, SDF _(C) type tunnel construction dedicated variable-speed contra-rotating axial flow fan, SDF _(D4) Energy-saving long construction tunnel four-stage contra-rotating axial flow fan, SDF _(E) New type tunnel dedicated axial flow fan, SDF _(P) New type tunnel construction dedicated variable frequency energy-saving fan, and hundreds of other specifications in five series.

II. Working Principle

The number of blades in the first and second stages is different. The two-stage impellers are very close to each other and rotate relatively. The first-stage impeller rotates clockwise, and the second-stage impeller rotates counterclockwise. After the first-stage impeller obtains energy, it directly enters the second-stage impeller for boosting and then discharges. The function of the second-stage impeller, in addition to increasing the airflow energy, also has the function of the stationary guide vanes of other types of axial flow fans. While obtaining the guided straightening circumferential velocity component, it smooths the airflow impact, increases the airflow energy, and reduces noise.

III. Structural Features

1. Impeller: The impellers of the fans manufactured by our company adopt an adjustable impeller design, which can be adjusted according to different ventilation needs. It also meets the ventilation needs of plateau environments. Material: Steel, and arc flame spraying treatment; its strength is 20 times that of ordinary materials, with advantages such as corrosion resistance and high strength.

2. Dynamic Balance Test: Our company has a ø2.0 dynamic balance test bench. All fans are tested before leaving the factory to ensure product quality.

3. Fan Noise and Vibration: Silencers are installed at the inlet and outlet ends of the fan to meet the standard values stipulated in JB/T8690 "Noise Limits for Industrial Ventilation Fans"; the A-weighted sound level noise LSA ≤25dB(A) at the best efficiency operating point; vibration is lower than the vibration effective value (RMS) 4.6mm/s stipulated in JB/T8689 "Ventilation Fan Vibration Detection and Its Limit Values".

4. Housing and Other Component Materials: The housing adopts double-layer plate welding, with ultra-fine glass fiber cotton lining in the middle to achieve good noise reduction effect. The fan is sturdy and durable, has a long lifespan, and has undergone rigorous surface treatment; the minimum design service life of the fan is not less than 15 years.

5. Fan Manufacturing Standards: The fans are strictly manufactured in accordance with national standards and relevant industry standards.

6. The fan has the characteristics of compact structure, long air delivery distance, high efficiency, convenient maintenance, and convenient repair.

7. The performance of the fan is strictly inspected before leaving the factory, and a relevant certificate of conformity is included.