The use of high pressure blow tanks for the pneumatic conveying of pelletised materials

Abstract

Blow tanks are widely used in industry as a material feeding device in pneumatic conveying systems. Because of their flexibility in operation they are also widely used to obtain conveying data for system design purposes. This is because a single unit is capable of feeding a very wide range of materials. They have a very high pressure capability and are capable of operation over a large turn-down ratio. In this chapter, the issue of their control is addressed, particularly with regard to the conveying of pelletized materials. Blow tank control characteristics are also presented, to illustrate both the means by which control is obtained, and the degree of stability achieved in conveying. A comparison with granular and fine materials is also included. Pelletized materials generally have a very distinct pressure minimum point in their operating characteristics and this feature is clearly illustrated. For comparative purposes, similar material conveying characteristics, and blow tank control characteristics, obtained for materials having good air retention, and for materials having neither good air retention nor good permeability, are also included, to illustrate the similarities and differences in material conveying capability, and the potential control of blow tanks used as conveying pipeline feeding devices for these materials.