Vertical Continuous Vacuum Pan

An apparatus for the improved vertical continuous pan for crystallization of sugar and the like, the apparatus comprising, in combination

• a cylindrical housing having a vertical axis in which plurality of vacuum chambers are stacked one above the other on a common axis;
• each chamber substantially having a ‘W’-shaped bottom with space below being surrounded by the passive steam of the chamber below;
• each operation chamber having associated therewith a fixed set point control for condition of massecuite and discharge volume per hour and that the per hour discharge volume of a given operation chamber is greater than the per hour discharge volume of the immediately preceding operation chamber;
• a heat supply means comprising vertical tube fixed annular calandria supplied by active heating steam from a common supply external to the cylindrical housing;
• a central downtake in which an axial flow impeller or a mechanical circulator is located;
• one or more mechanisms for controlling
• a) heating steam pressure,
• b) vapour pressure,
• c) massecuite condition,
• d) feed syrup supply proportion and flow rate,
• e) ratio of feed syrup to seed supply,
• f) massecuite level, and
• g) transfer of massecuite from the upper to the lower pan using transferring means which include gravity discharge means;
• a massecuite discharge pipe in the floor of every chamber equipped with a control valve regulated by a level sensor of the same chamber and connected to the massecuite supply pipe of the next lower chamber;
• an inlet means for introduction of feed syrup in each chamber connected to a common syrup feed header through a control valve regulated by a brix sensor;
• a means for continuously introducing seed crystals into the first operation chamber;
• an outlet means for continuously withdrawing sugar syrup and product cystals from the last operation vacuum chamber;
• means for exhausting vapour and non-condensables through a common vapour line connected to a condenser/vapour recompressor and also equipped with means for entrainment separation;
• means for removal of condensate;
• means for bypassing a particular operation chamber by arrangement of appropriate pipes;
• means for cleaning comprising valve-controlled steam supply line, hot and cold water supply lines with a wash out drain line connected to the massecuite discharge duct in the floor of the chamber and regulated by a control valve, outflowing into a common wash out drain pipe;
• characterized in that each operation chamber has a bottom mounted mechanical circulator housed in an insulated pocket in the vapour space segment of each chamber and not in additional space above the chamber.