POWDER FEEDER

PURPOSE: To quantitatively feed almost without weighing errors occurring in a powder quantitatively feeding device having a powder weighing hopper of small capacity below a powder feeding hopper of large capacity by fitting an air intake means having a filter communicating with open air on the ceiling surface of the powder weighing hopper. CONSTITUTION: When feeding powder, after the powder is first fed into a powder feeding hopper 3, a feeding port 2 is closed. Next, after a damper 5 is opened and a motor 12 is driven to rotate screw 10 and the powder is fed into a powder weighing hopper 7, a motor 12 is stopped and also the damper 5 is closed. Next, a feeding valve 20 is opened and a motor 16 is driven to feed the powder into the weighing hopper 7 little by little. The fed quantity is measured by a load cell 6, and when the measured quantity attains a prescribed one, the feeding valve 20 is closed to stop the supply. At this time, air is sucked into the powder weighing hopper 7 from an air intake means with a filter 14 to keep the inside of the hopper 7 at the same pressure as that of the atmosphere, thereby measuring errors do not occur.