The utility model discloses a closed
powder feeding device which comprises a
steel frame platform, an upper-layer support, a main material metering
system, a compensation feeding metering
system, a vacuumizing pipeline, a microbead feeding
system, a vacuum system, a weight sensor and a conveying pipeline. The main material metering system and the compensation feeding system are located on the uppermost portion of the whole device, and the microbead feeding system, the vacuum system and the
steel frame platform are all installed on the ground. A main
material transfer hopper in the main material metering system is connected with a vacuum system through a vacuumizing pipeline, the main material metering system and the compensation feeding metering system are both installed in a suspension mode and fixedly supported on a main material weight sensor on an upper-layer support, and the main material weight sensor is connected with the device
control system and detects the feeding weight in real time. And the microbead feeding system is communicated with the main material metering system through a
pneumatic valve and a conveying pipeline. A secondary
feeding mode is adopted, the self-cleaning effect of the pipeline is achieved through simple valve
layout and control, and a traditional mode that a feeding pipeline is cleaned through a draught fan is replaced.