| 摘要 |
PURPOSE:To stop the wasteful operation of a belt conveyor by refining and classifying the used molding sand for casting molds then putting once the sand into a hopper, taking out the recovered sand through the aperture of the hopper when the sand accumulates to a specified quantity in the hopper and conveying the sand by means of a belt conveyor to a storage tank. CONSTITUTION:Inclusions such as metals and clay are removed from the recovered sand obtd. by shaking out the used casting molds and cores, then the sand is pulverized and refined. The recovered sand subjected to such refining is classified by grain sizes in a classifier 17 and the classified sands are stored once in hoppers 24, 25, 26 for each of the classes. A spring 242 which supports the hopper is compressed by the weight of the recovered sand and a receiving hopper 241 descends when the recovered sand accumulates to the specified quantity in the hopper 241. The belt conveyor 18 is operated to drop the recovered sand into a storage tank 21 at the same instant when a valve 245 in the lower part of the hopper is opened upon contact of a limit switch 244 attached to the hopper with a supporting material 243. The belt conveyor 18 is operated only when needed without being constantly operated and therefore the electric power for driving is considerably economized. |
