| 摘要 |
PROBLEM TO BE SOLVED: To improve closability between inlet/outlet valves and end faces of wall parts of cases by forming first and second spaces around the wall parts of the cases which determine a powder inlet and powder outlet. SOLUTION: Inlet and outlet valves 13, 14 are, at the time of closing, in contact with end faces 25, 26 of wall parts 4A, 4C of cases for determining powder inlet and outlet 11, 12. Spaces 21, 22 communicated with a powder flow passage 24 and an operation chamber 8 are formed around the wall parts 4A, 4C of the cases, so that the contact area between the valves 13, 14 and the end faces 25, 26 is remarkably reduced. Even in the case that powder is accumulated on the end faces 25, 26 and the valves 13, 14, the inlet and outlet valves 13, 14 are brought into close contact with the end faces 25, 26 for improving closability. In addition, owing to the small contact area, the powder can be removed from the end faces 25, 26 accompanied with opening and closing of the valves 13, 14. The removed powder speedily enter the spaces 21, 22 around the end faces 25, 26. |
