Adjustable air stream introducing device

An adjustable air stream introducing device for reinforcement of a blowing power of a primary air stream flowing through a duct which is confined by a tubular wall, the tubular wall including a surrounding end portion to define an outlet port for delivering the primary air stream, said adjustable air stream introducing device comprising:

• a tubular coupler having an inner surrounding wall which surrounds an axis and which confines a conduit adapted to be disposed downstream of the duct, said inner surrounding wall including proximate and distal surrounding segments relative to the surrounding end portion, said proximate surrounding segment being adapted to surround and to be disposed distant from the surrounding end portion in radial directions with an annular space therebetween;
• a surrounding seat member including
• a first inner peripheral edge disposed to surround the axis and adapted to engage the surrounding end portion,
• a first outer peripheral edge which is opposite to said first inner peripheral edge in the radial directions and which is disposed to engage said proximate surrounding segment, and
• a surrounding seat area interposed between and integrally formed with said first inner and outer peripheral edges,
• said surrounding seat member having a plurality of internal ports which are disposed in said surrounding seat area to communicate with said conduit and which are angularly displaced from one another about the axis;
• a surrounding sash member including
• a second inner peripheral edge disposed to surround the axis and adapted to be disposed adjacent to the surrounding end portion,
• a second outer peripheral edge which is opposite to said second inner peripheral edge in the radial directions and which is disposed adjacent to said proximate surrounding segment, and
• a surrounding sash area interposed between and integrally formed with said second inner and outer peripheral edges,
• said surrounding sash member having a plurality of external ports which are disposed in said surrounding sash area and which are angularly displaced from one another about the axis, said surrounding sash member being disposed to overlie and to be turnable relative to said surrounding seat member about the axis between a fully open position, where said external ports fully coincide with said internal ports, respectively, and a partially open position, where said external ports partly overlap said internal ports, respectively;
• and
• a motor-driven actuator member disposed to initiate rotating movement of said surrounding sash member about the axis between the fully open position and the partially open position.