| 摘要 |
PURPOSE:To quantitatively discharge powder and to keep the seal condition by disposing a group of small-diameter paths having a function of self opening and closing midway in a powder layer. CONSTITUTION:Powder A supplied from a receiver tank 3 into the upper powder bath 11 forms a powder seal layer H1 in the upper powder bath 11, and further the powder A flows through each path of small-diameter pipes 5 of a unit 4 to form a powder seal layer H2 in the lower powder bath 12. The first seal layer H1 and the second seal layer H2 are summed up to form a set of seal layers H between a discharge port of the receiver tank 3 and an inlet port of a rotary valve 2. When the negative pressure of the receiver tank 3 is temporarily below a setpoint, each small-diameter pipe 5 is closed up, so that the negative pressure may have no effect upon the second seal layer H2. Thus, the powder A continues to be discharged quantitatively. |
