Automatic sand blasting machine for inner walls of pipelines

The invention provides an automatic sand blasting machine for the inner walls of pipelines. The automatic sand blasting machine comprises a material storage device, a conveying device, a feeding device, V-shaped supports, pipe rotation driving devices and sand blasting devices. The V-shaped supports, the pipe rotation driving devices and the sand blasting devices are arranged as two groups to formtwo sand blasting stations, and sand blasting operation can be carried out on two steel pipes at the same time; the sand blasting devices can adjust the positions of spray guns according to the pipediameters of the steel pipes, and L-shaped rocker arms for mounting the spray guns do reciprocating swinging motion under the driving of air cylinders and are matched with the rotation of the steel pipes to evenly spray grinding materials to the inner walls of the steel pipes; the two spray guns are respectively connected with two sand blasting tanks, when one of the spray guns is used for carrying out sand blasting operat