Negative pressure material fed circularlation recovery type sand blast machine

The utility model relates to a negative-pressure material feeding circulation recovery type sand spraying machine, which comprises a high-pressure air source, a spray gun, a sand material cylinder, a filtering cylinder, a dust cylinder, a vacuum pump and a plurality of pipelines, valves. Through making use of the negative pressure that the high-pressure air can generate the internal expansion in the nozzle of the spray gun; the sand materials are sucked into the mixing chamber of the spray gun; then, through making use of the expanded high-velocity airflow, the sand materials are accelerated in the sand spraying pipe of the spray gun, and finally, the sand materials are sprayed onto the surface to be treated. Accordingly, the corrosion layer or the oxidation scale on the surface is removed; through the recovery of the vacuum pump and the filtering of the filtering cylinder, the sand materials can be used circularly, and simultaneously, the pollution of the dust to the environment can be avoided. Through adopting the negative-pressure feeding way, the stable and continuous feeding can be formed, and accordingly, the treating efficiency of the surface can be improved.