Casing
The all-metal casing shall be manufactured using pre-galvanised sheet steel suitably stiffened. Casings shall incorporate flange connections at each end. Motor supports shall be of pre-galvanised sheet steel construction and shall have an aerodynamic profile.
Motors
The single range of units shall have an AC external rotor motor fitted as standard. The motor contains sealed for life bearings. Thermal Class of motors to THCL 130 or 155 dependent on size. All motors are suitable for use in ambient air conditions up to +60°C. Electrical connection shall be via an IP55 terminal box mounted on the side for easy customer connection.
Impellers
Impellers shall be made from high-performance composite material with backward-curved, aerofoil section blades. Three-dimensional blade geometry with diagonal air discharge shall provide high efficiency and low acoustic emissions, directly driven by the motor to provide a smooth airflow through the unit.
Control
Speed control shall be via stepped Transformer.
Quality Management
Units are to be designed and manufactured with procedures as defined in BS EN ISO 9001. All Multiflow SMB units are to be tested to ISO 5801 (airside performance) and BS ISO 13347-1 (sound performance).