Return-free gas-powder conveying device

The invention discloses a non-return gas-powder conveying device which comprises a fan, a mixer, a blanking bin and a storage bin, the mixer comprises a mixing pipe extending in the horizontal direction, a blanking pipe is mounted on the upper side of the mixing pipe, and the mixing pipe is divided into an air inlet section and a mixing section by taking the blanking pipe as a boundary; a spiral plate is arranged in the air inlet section, an air inlet connecting pipe is arranged at the end part of the air inlet section, and an expansion pipe is mounted at the end part of the mixing section; a discharging opening is formed in the lower end of the discharging pipe and extends downwards into the mixing pipe; an outlet of the fan is communicated with the air inlet connecting pipe, the expansion pipe is communicated with the storage bin through a conveying pipe, and a discharging port in the bottom of the discharging bin is communicated with the discharging pipe through a feeding pipe. According to the powder conv