Hot air treatment in fluidised bed - esp. of heat sensitive material with air inlets above bed floor

摘要

A fluidised bed operates with hot gas, esp. hot air; all the hot air inlets are in the fluidised be chamber at some distance above the chamber floor and oriented so as to directed the hot air jets towards the floor; in all parts of the chamber, the inner walls which come into contact with the flow paths of the incoming gas are insulated. Pref. the directions of the jets as viewed in plan are oriented not towards the centre of the chamber but at an acute angle from it. Both this angle and the angle of vertical tilt are pref. adjustable. In any form of treatment where hot air or gas is used, but in particular where a heat sensitive granulate is treated in the bed. The positioning of the hot air inlets within the chamber rather than below a perforated floor ensures that neither the floor nor any other part of the structure is at a temp. excessively higher than the material in the bed. It is not therefore necessary to allow for such a high temp. drop between incoming air and treatment temp., nor is there a danger of heat-sensitive material becoming damaged by contact with hot metal parts.