Dense phase conveying moves the ingredients — usually blends — through similar piping as dilute phase conveying but with the intent of maintaining the integrity of the blend, according to Kevin Pecha, sales manager-food, AZO Inc., Memphis, TN. Dilute phase conveying has the potential to segregate  blends or mixes as the heavier and lighter particles travel through the  system. “Dense phase conveying tries to keep the product in a grouping, or slug, during this transport,” he explained. “Transporting in dense phase can be accomplished either using vacuum or pressure, but various densities of blends may require different settings on the equipment to optimize the dense phase conveying.”

Dense phase is preferred for either abrasive or friable materials, noted Jason Stricker, national accounts manager, Shick Solutions. For sensitive materials, using an inert gas instead of air may prevent oxidation. Additionally, the lower speeds increase energy efficiency and prevent materials from breaking down as well as reduce excessive wear on the pipes.