Dichtstromförderung

High density pneumatic conveying . In distinguishing between high density pneumatic conveying and low density conveying it is insufficient to merely use the solids loading to characterize the various flow states. Less ambiguous classification is possible only on the basis of the diagram of state of pneumatic conveying. Most flowable bulk solids can be transported through normal smooth‐walled piping in the high density mode with normal conveying equipment. In contrast, fine‐grained products in particular tend to adhere to the wall and form blockages. Paying due attention to the differing flow properties of various bulk solids and to the mechanisms of blockage formation and clearance, various new conveying techniques and piping types have been developed in recent years, permitting in some cases the transport of adhering, abrasive, and attrition‐sensitive materials. Since conveying pressures up to about 6 bar are usual in the high‐density regime, various combinations of pressure vessels are primarily used for feeding the bulk solids into the conveying pipes. The advantages of conventional, and also special high‐density conveying systems are discussed with the aid of examples.