| 摘要 |
PURPOSE:To steplessly regulate the opening area of an opening part, by a method wherein a cylindrical opening part, forming a feed opening part for a powdery material, is formed through combination of plural variable blades, and rotation of the variable blades is controlled. CONSTITUTION:Three or more variable blades 3 in a flat manner or having the same curvature of surface of positioned to a flange part 2 at the lower end of a cylindrical body 1 on a powdery material conveyance route so that adjoining edge parts are overlapped with each other to form a cylindrical opening part 31. A hopper 6 is disposed below the variable blades 3, forming the cylindrical opening part 31, and a portion between the hopper 6 and a flange part 2 is surrounded with a canvas 7. Free end parts 31a of the variable blades 3 are directed to a central direction by means of an expandable driving mechanism 8, formed with a position rod and a cylinder, for focussing. As a result, the opening area of the opening part 31 can be continuously and steplessly regulated in a manner to throttle the opening area.
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