Specifications

Section 1
1-4 LA-306 Operation & Theory
1.3 Furnace Elements
1.3.1 Furnace Arrangement
Parts are carried from the load station through the heating and cooling sections of the furnace to the unload
station on a 152 mm (6-inch) wide belt driven by an adjustable speed motor. Maximum vertical parts clearance
inside the furnace is 50 mm (2 inches).
Figure 1-9 Process Sections
Process atmosphere is controlled much like a clean room: pressurized gas is pushed through the heating chamber
insulation providing a pre-heated, laminar flow for a uniform, stable atmosphere.
The heating chamber is divided into 3 zones separated by insulation dividers so that adjacent zones can have
different setpoint temperatures if required. Control starts with K-type thermocouples in each zone quickly
sensing changing conditions and feeding these signals to individual digital PID controllers for each zone. The
PID loop controllers drive arrays of IR quartz heating lamps inside the heating chamber so as to maintain the
desired temperature setpoint in each zone.
Product cooling is by radiant cooling and CDA or N2 gas convective cooling in an enclosed tunnel, with exterior
fan heat removal.
1.3.2 The Process Chamber
The process chamber contains an entrance baffle with an eductor equipped exhaust stack, an IR heating section,
a transition tunnel between the heating and cooling sections, and a closed atmosphere cooling tunnel, arranged as
shown here:
Figure 1-10 Furnace Internals
Together, the individual sections function as a unit to provide a carefully controlled gas atmosphere, precise
temperature profile and two-stage controlled atmosphere cooling.