the circulating movement being promoted by inducing differing degrees of fluidisation in different parts of the bed

Full Title

Fluidised bed combustion apparatus > with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed > the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone > the circulating movement being promoted by inducing differing degrees of fluidisation in different parts of the bed