Abstract: A spiral gas stream is generated in a pipeline when a uniform flow of gas flowing in a cylinder having inner diameter larger than that of the pipeline is introduced through a funnelform reducer into the inlet of the pipeline and bringing the mean gas stream velocity in the pipeline faster than 20 meter per second. The uniform flow of gas is formed in the cylinder easily when outside low pressure gas is fed into the cylinder through a feed gas inlet pipe installed diagonally at the side of the cylinder apart from the bottom plate so as to make the flow line of the feed gas to cross the axis of the cylinder and inclined toward the bottom plate. When solid particles are introduced into the spiral gas stream zone, they are transported to the outlet of the pipeline. As the compressed gas layer is formed along the inside wall of the pipeline by the spiral motion of gas stream, solid particles don't contact directly with the inside wall of the pipeline and don't hurt it.