- Structure Type
Jet fans should be directly driven and be composed of axial airfoil blade impeller and streamlined air deflector on upstream of impeller and silencers collected to both sides of fan housing using high strength bolts. Safe guards should be mounted on both inlet and outlet of the fan to ensure safe running.
According to ventilation requirement, jet fans include unidirectional and bidirectional. Unidirectional jet fan is designed for one directional ventilation and for counter ventilation under special conditions sometimes with 50%～70% thrust force of normal ventilation. Bidirectional jet fans shall be used as normal and counter directional ventilation with same performance.
- Fan Shell
Jet fan shell should be in quality steel and be rolled to cylinder and then continually welded, with flanges turned up using special flange machine finally. Motor brackets are continually welded with fan casing to ensure high strength and stiffness to support dynamic loads.
Hub and blades of jet fans should be casted in high strength aluminum alloy. Each blade must be tested by X ray to ensure a high quality for reliable running.
Blades using optimal aerodynamic airfoil profile should be fastened to hub with high strength bolts. Every impeller should be dynamically balanced. Blade pitch should be adjustable in static state to meet different operating conditions.
The silencer should have two cylinder structure layers consisting of inner perforated plate and outer steel shell that is rolled and fully welded, and the middle is filled with special superfine glass fiber material which has flame retardant properties of A-class with non combustible, non pest risk, anti damp.
- Surface Treatment
Surface of jet fan casing should be treated with anticorrosion and antirust. Surface treatment should contain at least two layers of high temperature resistant primer. Fan surface should be galvanized to ensure long time corrosion proof for special requirements.
Jet fan should be fitted with squirrel cage asynchronous motor, standard product of totally enclosed type of damp heat, class H insulation, IP55. Motors are lubricated using sealing grease with extended lubricating nipple on fan shell. Motor lead cables should extend to the fan shell for easy wiring.
- Smoke Removal Certification
Jet fans should meet the requirements of JB/T10489《Technical conditions of jet fan in the tunnel》. This type of jet fans must pass testing according to GA211-2009《Test method for resistance to high temperature of fire smoke exhaust fan》by fire safety inspection agencies accredited by country. Fans shall continually run for 60min at 250℃ reliably and has test report by relevant agency with qualification.
Aluminum nameplate shall be permanently fixed and clearly indicate legible fan number, model and product serial number (i.e. unique identification of each fan), ensuring that customers can conveniently query the history records of the accessories.