Patent ID: 11964823
Assignee: JOHN BEAN TECHNOLOGIES AB
Field: Handling (Mechanical engineering)
Classification: CPC A  B | IPC B

Claim 15:
16. A thermal processing apparatus, comprising:
(a) a housing;
(b) a conveyor belt arranged into two spiral interconnected stacks positioned side-by-side to each other within the housing, the conveyor belt of each stack having an inside edge engaged against the exterior of an upright drum tower for driving the conveyor belt in tiered angular travel paths for supporting work products during thermal processing;
(c) the drum towers having a covered exterior with openings formed in the covered exterior that constitute from about 5% to about 20% of the area of the covered exterior;
(d) an upright partition wall positioned between the two spiral stacks of the conveyor belt;
(e) a top sheeting disposed over the two spiral stacks of the conveyor belt;
(f) a circulation system positioned in the housing with respect to each spiral conveyor stack at locations spaced away from the partition wall to draw spent gaseous thermal processing medium from the tiers of the spiral stacks and direct the thermal processing medium along upward flow paths located outward of the spiral stacks to an elevation above the top sheeting, and then across the top sheeting toward the center partition wall, and then downwardly along a flow path exterior of the spiral stacks and adjacent the partition wall to laterally enter the tiers of the conveyor belt stacks;
(g) the top sheeting for each of the conveyor belt stacks defining at least one entrance opening disposed above a corresponding drive drum tower to provide an alternative flow route for a portion of the thermal processing medium downwardly into the drive drum towers and then flow out of the drive drum towers through the openings in the covered exterior of the drive drum towers and across the tiers of the conveyor belt stacks; and
(h) wherein the percentage of thermal processing medium flowing through the at least one entrance opening in the top sheeting is in the range of 2% to 12% of the total flow of the gaseous thermal processing fluid.