The FMC Technologies' Roto-Tube™ is designed for high-volume cooling of free-flowing granular materials. Its unique design with hollow tubes provides an extremely large heat-transfer surface per linear foot of drum for rapid, high-volume cooling. This design relies on little or no air circulation through the drum, minimizing or eliminating the need for auxiliary dust collection equipment.
Applications are any free flowing material that requires cooling. Sample applications include gypsum, ammonium nitrate, sodium phosphate, and soda ash.
The Roto-Tube™ drum consists of a series of tube sections positioned alternately at 90°. The drum is partially submerged in water. Each tube is a separate heat exchanger with its own water entry and discharge. As the drum revolves, the material is conveyed gently through the drum minimizing dusting and degradation. Water (or other liquid) flows through the tank for counter-current cooling and highest cooling efficiency.
The surfaces containing hot material are immersed in the cooling water with each revolution. Thus, the surfaces that contact the hot material are continually cooled. As the cooled material reaches the end of the drum, it is efficiently collected by an arrangement of annular buckets and then discharged. With large radiation and conduction surface, the drum can be considerably shorter than comparable coolers of equal capacity requiring less floor space. Externally heated air, along with any water vapors generated in the cooling bath is free to escape through flues and stacks rather than through restrictive pipes and headers.