Method for controlling solid particle flow in an evaporator

A method for controlling a flow of solid particles having a size larger than a critical size in an evaporator, the evaporator for concentrating slurries or solutions containing solid particles and liquid, the critical size being a predetermined size above which the solid particles cause unacceptable clogging of the evaporator, said method comprising the following steps:

• separating from the liquid the solid particles which have a size larger than the critical size by introducing the slurry or solution to the interior of a separation chamber having apertures which allow particles of the critical size or smaller to pass therethrough, and which apertures do not allow particles larger than the critical size to pass from the separation chamber;
• retaining inside said separation chamber at least a portion of said particles initially larger than the critical size, until at least a portion of the particles initially larger than the critical size are reduced in size to at least the critical size or smaller by impact of oversize particles against a separation chamber wall, so that particles which are reduced to the critical size or smaller can pass through said apertures;
• channeling from the separation chamber to a reservoir (i) a portion of the separated solid particles larger than the critical size, and (ii) a portion of the liquid;
• channeling the remaining liquid from which the solid particles were removed to a heat exchanger within the evaporator for concentration of the remaining liquid;
• and
• channeling the concentrated liquid to said reservoir for recombining with the separated solid particles larger than the critical size and with the portion of the liquid which carried said solid particles larger than the critical size to said reservoir.