| 摘要 |
PURPOSE:To prevent turbulence of flowing air and reduce the whiz of the flow by providing a pair of air flow-controlling valves each of which is gently curved with regard to the direction of a flow of air. CONSTITUTION:A pair of air flow-controlling valves 11, 11 are attached, by means of hinges 15, 15, to a cross-shaped supporting member 12 set at right angles to the axis in a duct 14 with a rectangular cross section. Each of the air flow-controlling valves 11 consists of a rectangular plate corresponding in shape to the rectangular duct 14 and this rectangular plate 11a is gently curved with regard to the direction of a flow of air. Each air flow-controlling valve 11 moves on the hinge 15 and opens or closes the duct downstream. Opening-adjusting screws 13 are also provided, each having the base end 13a on the downstream side; the forward end part of each screw is run through the base end part of the air flow-controlling valve 11 and fixed to the cross- shaped supporting member 12. |
