Axial-flow roof fan

Axial Flow Roof Fan – Product Introduction

1. Product Overview

The axial flow roof fan (typical model: DWT-I) is a ventilation device installed on building rooftops. Its airflow direction is parallel to the blade axis, offering high air volume with moderate static pressure. This fan series features a molded axial-flow impeller and a dedicated motor with direct drive. The complete unit mainly consists of the impeller, fan casing, cowl, transmission components, hinged dampers, bird screens, safety nets, and other parts.

2. Core Features

1. High air volume, moderate pressure

The axial flow roof fan delivers high airflow with lower pressure compared to centrifugal fans, making it suitable for applications with short or no ductwork and direct exhaust.

2. Low noise operation

With wide blades, large chord length, spatially twisted and inclined blade profiles, and CAD multi-objective optimization, the fan achieves the required airflow and pressure at low rotational speeds, effectively reducing noise.

3. Lightweight, high strength, and corrosion resistance

Key components such as the casing and cowl can be manufactured from FRP (fiber-reinforced plastic), offering corrosion resistance, aging resistance, and light weight. Depending on the corrosiveness of the medium, the impeller can be made of ABS (engineering plastic), FRP, or aluminum alloy.

4. Smooth operation and long service life

Low moment of inertia and high dynamic balance accuracy ensure stable long‑term performance, exceeding industry standards.

5. Bidirectional reversible function

Upon request, the fan can be designed for reversible operation, providing equivalent performance in both forward and reverse directions, enabling dual-purpose supply and exhaust ventilation.

6. Attractive appearance

The cowl is made of FRP with smooth curved surfaces. Alternatively, it can be manufactured from steel with galvanized and powder‑coated finish per customer requirements.

3. Application Scenarios

Axial flow roof fans are widely used in the following fields:

– Industrial plants: ventilation and exhaust in power plants, chemical plants, rubber factories, machinery manufacturing, metallurgy, paper mills, etc.

– Commercial buildings: air exchange in shopping malls, gymnasiums, cinemas, underground parking garages, and other crowded spaces.

– Warehousing and logistics: forced exhaust and heat dissipation in warehouses and distribution centers.

– Agriculture: ventilation, temperature and humidity control in farms and greenhouses.

– Special environments: available in corrosion‑resistant versions (for chemical, electroplating, wastewater treatment, and other corrosive environments) or explosion‑proof versions (for flammable and explosive locations).

4. Installation Essentials

1. Foundation preparation: Before installation, prepare a concrete foundation on the roof with embedded anchor bolts; the centerline deviation shall not exceed 10 mm.
2. Vibration isolation: Place rubber vibration‑isolating pads with a thickness of no less than 6 mm between the foundation and the fan base.
3. Vertical installation: The fan must be installed vertically, with a levelness deviation not exceeding 1/1000.
4. Clearance adjustment: The radial and axial clearances between the impeller and the casing must be uniform and comply with the technical documentation.
5. Motor protection: For outdoor rooftop installation, an IP55‑rated motor must be used.

5. Selection Considerations

1. Calculate air volume: Required air volume = space volume × air changes per hour (typical workshops: 6–10 changes/hour).
2. Determine static pressure: Estimate system resistance based on duct length, number of bends, etc. Choose axial flow for low resistance; choose centrifugal for higher resistance (>300 Pa).
3. Material selection: For ordinary air, use carbon steel / galvanized steel; for corrosive gases, use FRP or 304 stainless steel.
4. Explosion‑proof requirements: In flammable and explosive areas, an explosion‑proof motor (Exd II BT4 grade) must be used and carry CCC explosion‑proof certification.
5. Fire protection needs: For smoke exhaust in fire scenarios, select a fan with CCCF certification specifically designed for fire protection.