| 摘要 |
A system for delivering a particulate material has a closed storage hopper for the material, the hopper having a bottom hopper outlet and a check valve connected to a top portion of the chamber for venting positive pressure from the chamber; a venturi eductor having a material inlet for feeding the material, an eductor outlet, and a gas inlet; a gas feed valve, the gas feed valve being openable in response to a feed signal for activating the educator; a hopper passage connecting the hopper outlet to the eductor material inlet; a hopper outlet valve for closing the hopper outlet in response to a hopper signal; a stir valve for pressurizing the hopper passage in response to a stir signal for agitating the material in the hopper; and a pressure sensor for momentarily activating the stir signal in response to an absence of the material at the material inlet, the system being operative in a transporting mode wherein the hopper valve is open, the feed valve is open, and the stir valve is closed; a stirring mode wherein the hopper valve and stir valves are open; a purging mode wherein the hopper and feed values are closed and the stir value is activated; and an override mode wherein the hopper and stir valves are open and the feed valve is closed. The system automatically responds to a predetermined number of activations of the stir signal within a fixed period of time, by entering the purging mode. |
