Dilute phase conveying is the act of using a pneumatic conveyor to transfer materials from one place to another inside an enclosed are. Dilute phase conveyors are used for conveying non-abrasive loose materials when high material velocities and product degradation is not present. One of the main uses for this style of conveyor system is to unload materials from a rail car into a factory for further processing.
First, the dilute phase conveying system uses vacuum pressure to unload the railcars into storage silos. Vacuum blowers transfer the material to the designated silos based on weight or size. Most systems have the option for manual or automatic material sorting. A second stage of the system uses vacuum pressure to transfer the material from the silo to the in-plant processing bins. Another blower sends the air back to the silo to help continue the vacuum circuit. Without the return air system, the pressure build-up inside the silo could lead to problems with the conveyor system.
After the materials are placed inside the in-factory hoppers, the materials can then be used for processing inside the factory. In many cases, the bins inside the factory have spouts at the bottom of the container to allow for easy transfer of the materials in further processing. The kinds of materials that are transported this way often include grain, seeds, corn, and small pieces of coal. Depending on the power level of the vacuum, a variety of sizes of materials can be picked up through this system. However, since the conveyor uses high pressure to transfer the items, it is not ideal for use with products that can break down easily or become damaged from abrasions or vibrations.