What are the Structural Characteristics and Working Theory of SDF Series Tunnel Axial Flow Fan?

The SDF series tunnel axial flow fan is a ventilation device specifically designed for tunnel applications. It combines an axial flow fan unit with noise reduction features to provide efficient air circulation with minimal noise emission.

Structure:

The fan consists of several key components: collector, front muffler, main unit group, impeller group, motor, and back muffler.

The barrel and structural parts are welded steel plates. The inner barrel utilizes a perforated plate filled with sound-absorbing material to dampen airflow noise.

The motor is an assembly-type, three-phase asynchronous motor (Y series) mounted on the barrel with bolts. The rated voltage can be customized to 380/660V or 660/1140V based on user requirements.

Each air duct connects to the fan using flanged bolts, ensuring a secure and leak-proof connection.

The impeller directly connects to the motor for a robust and stable structure, promoting ease of operation and maintenance.

Working Theory:

1. Contra-rotating Design: The SDF series fan employs a contra-rotating structure, featuring two impellers spinning in opposite directions. This design reduces internal resistance within the fan, thereby increasing overall efficiency.

2. Multi-stage Operation: The fan can be configured for multi-stage operation to cater to varying ventilation needs. However, using a single stage results in lower efficiency.

3. Aerodynamic Performance: The overlapping blades between the front and back stages are strategically designed with coprime numbers to prevent inter-stage gas pulsation. This ensures the fan delivers efficient airflow over long distances and performs stably even at low flow rates. Additionally, it maintains a wide operational range with high efficiency and low noise levels.

4. Electrical Safety: The fan is equipped with a grounding device for reliable earthing. This is crucial to prevent electrical leakage and ensure safe operation.

5. Flanged Outlet: The diffuser section of the barrel features a flanged outlet for easy connection with a flexible air duct.

In summary, the SDF series tunnel axial flow fan offers a well-designed solution for tunnel ventilation. Its combination of efficient airflow, noise reduction features, and robust construction makes it a valuable tool for various tunnel applications.