Pneumatic conveyor may be defined as the art of transporting dry bulk materials through a pipeline by either a negative or a positive pressure air stream. It is also described as the harnessing of air movement to accomplish work. This air stream or air movement is nothing more than air in motion. When in motion air becomes wind, and does such things as gently waving growing grain, pushing ships or even devastating miles of forests. The simple pneumatic conveyor is only a miniature hurricane directed to a certain destination by means of a pipe, with the movement of air caused by introducing it into the pipe at a pressure above normal or by lowering the pressure below normal at the delivery end. In either way, this air moves to regain a normal or absolute pressure and when moving with sufficient velocity, will carry objects in its path, depending on its substance or weight.
Pneumatic conveyors applied to the handling of materials between segments of processes have provided adaptability and complete reliability thus affording economics in not only the process but also the overall plant layout and arrangement. Pneumatic conveyors applied to so many industries like a cement, baking, brewing & distillery, kaolin, plastic, rubber, pulp & paper, feed.
The term pneumatic conveyor is commonly used to describe two methods or transporting bulk materials by means of compressed air power, negative or positive. The first method is the production of a low, medium or high velocity air stream into a pipe line system suspending the material in the air stream. The second method is aerating or fluidizing the material and then poring the fluidized column of material through pipeline system by the energy of expanding compressed air. The basic equipment operating under this two method may be divided into six distinct type part by reference their air requirement which may range from a few cubic feet of air per minute to substantial volume. There are six type of pneumatic conveyor Vacuum, Low pressure, medium pressure, High pressure, combination vacuum pressure system, Air activated gravity, Closed circuit system.