Method for treating conduit to improve flow characteristic and resulting conduit product

In an apparatus for reducing the formation of fines and streamers in the gas conveying of plastic particles wherein

• the interior of a plurality of particle conveying conduit sections are treated by shot-peeing the interior wall means of each of said sections, with shot being impacted against said wall means of each of said section at an acute, impacting angle, the apex of which points generally longitudinally of each said section toward one thereof;
• the improvement comprising:
• an assembly of said plurality of shot-peened, particle conveying conduit sections defining conduit means wherein the apexes of said acute, impacting angles all point generally in an intended longitudinal flow direction of said plastic particles;
• means for flowing said plastic particles through said assembly of shot-peened particle conveying conduit sections in said intended flow direction with
• the generally longitudinal flow direction of said particles through each said section forming, at the shot-peended interior wall means thereof, and acute, particle flow to shot impact direction related angle, with respect to the directions of impacting of said shot, with these angles being oriented in each of said sections with the angle apex thereof generally pointing toward said one end thereof;
• and
• said orientation of said particle flow to shot impact direction related angles being maintained throughout said conduit means and being operable to reduce the level of fines which would be generated by a reversal of said flow direction of said plastic particles.