| 摘要 |
PURPOSE:To prevent abrasion of the inner surface of a transport pipe and crushing of granular powder by blocking a discharge opening when a tank contains a predetermined very little amount of granular powder in transporting granules such as ore in the tank by pressurized air. CONSTITUTION:A predetermined quantity of granular powder 10 is poured into a blow tank 1, and the interior of the tank 10 is pressurized to be a set pressure P1 through a pressure alarm device 8 from a valve 19. The, valves 12, 21 are opened to supply the granular powder 10 together with pressurized air through a discharge opening 11, a pipe 15, the valve 12 and a pipe 13 to a hopper 14. When the granular powder 10 in the tank 1 comes to a predetermined very little amount, powder flow resistance in the pipe 13 decreases remarkably so that the pressure in the tank 1 drops below steady pressure P2. Such dropped pressure is detected by the pressure alarm device 8, and the valve 12 is blocked by the detecting signal to stop discharging the granular powder 10, which can prevent abrasion of the inner surface of a transport pipe and crushing of the granular powder 10. |
