Effect of Insertion Depth of Injection Pipe into Powder Bed on Pneumatic Conveying Characteristics of Suction Nozzle

In the negative pressure system of pneumatic conveying, the authors previously proposed a highly-efficient and constant feeding system of a powder, which was equipped with an injection pipe at the center of the suction nozzle. In this paper, we examined the effect of insertion depth of injection pipe into the powder bed from the tip of the suction nozzle. As a result, it was found that the optimum insertion depth which gives the highest nozzle efficiency and constant feeding exists for a given condition. The powders behavior near the injection pipe at a different insertion depth was identified through the powder flow visualization.