Many products within the food industry fall into this category. As an example, if a consumer opens a bag of cheese puffs and finds that half of them are broken into little pieces, they will quickly change product brands to someone with whole cheese puffs. Degradation to the final product is a highly important priority to any manufacturer of goods. The next best application for dense phase is on abrasive materials. The higher velocities associated with dilute phase conveying can lead to rapid pipe wear.
Many materials are so abrasive that they can wear a hole in a pipe elbow in just a few weeks.
Many minerals and chemicals fall into this category. The pipe wear can also result in a contamination problem because the pipe material will become mixed with the product. There is really only one other main reason for selecting dense phase. This is typically found within the plastics and petrochemical industry. Some of the softer plastics, such as polypropylene and polyethylene, will smear onto the pipe wall when the product slides along the outer wall of an elbow in a dilute phase transport system.