Pneumatic conveying in the plastics industry has traditionally been dilute phase. Many products, however, cannot be successfully handled by rotary valve type systems, and dense phase has become an accepted method for conveying plastic pellets (e.g., angel hair, streamers, etc.), powders and many flake and pelletized resins. Many of these materials, such as flake resins and phenolic resin pellets, are very fragile and benefit from gentle handling using low velocity. Furthermore, some resin powders can be very cohesive and sticky, hence more suitable for conveying in a dense phase regime.