Raining sand feeder is a special sand adding equipment in V process. The working principle of this equipment is that the vibrating table will raise when sand box move to the position under the raining sand feeder. Then the up surface of the sand box will be tightly sealed with under surface of raining sand feeder. There is a rubber blanket at the under surface of raining sand feeder to avoid RNTR. ESTS and guarantee the sealed condition and then the cylinder rod will come out and gate and at the same time, we begin to add sand into flask.