2. Structural Introduction
The RT3-100-12 bogie hearth furnace is mainly comprised of furnace body,
lining, furnace door and door compression system, bogie, heating element,
circulation device and temperature control system.
2.1 furnace body
The wholesale car bottm furnace body steel structure is made from 8-12#
sectional steel and ≥4mm steel plates. The side pillar and back pillars are
made from sectional steel, and are reinforced with sectional steel bracings.
The external wall of the furnace is painted with 2 layers of primers, and 2
layers of coating paint. The key part of the furnace is painted with heat resistant
paint.
2.2 lining
The heat treatment furnace trolley is built with an all-fiber system. The lining
material used is quality aluminum fibers fixed by round steel parts. The aluminum
fibers are pre-compressed into blocks (compression gravity: ≥230Kg/m3 ) and then
fixed to the furnace body by round stainless steel parts. This refractory lining
structure has the advantages of low heat conductivity, strong anti-shock capacity,
and anti-erosion. The lining has a total thickness of 350mm. The silicate aluminum
fiber resists a maximum temperature of 1260℃.
2.3 furnace door and door up-down system
The high temperature trolley type furnace door is comprised of all-fiber lining and
steel structure casing. The door frame is made of 12mm steel plate. The door is
built with silicate aluminum fiber blocks same as that for the furnace body. The
overall structure of the furnace maintains its shape while heated.
Driving method of door: The furnace door is electrically lifted upward and downward
by the hoist. And it is sealed by spring.
2.4 bogie
The bogie is comprised of bogie frame, wheels, refractory bricklaying body, heat
resistant bogie face plate, heating elements, and bogie driving mechanism.
bogie structure: the bogie frame is made from 14# beam and 12mm steel plates.
The bogie could work for a long time without deformation at full load.
wheel: The wheels are made from ZG55# steel casting. The transmission shaft is
made from 45# steel, and it is heat treated. The transmission bearing is of the heavy
type pillar bearing to bear the weight. There are a total of 6 of wheels, and each
wheel is of diameter 240mm.
bricklaying body: The bogie is built with a combination of high alumina refractory bricks,
light refractory bricks, and heat preservation bricks. The bricklaying body of the bogie
has heating elements installation slot for easy installation of the heating elements.
The impacted parts and weight bearing area are bricked especially with heavy type
high aluminum refractory bricks. There is also free space left for the refractory lining
expansion when heated.
Bogie face plate is cast with Ni7N, 30mm. The max temperature≤1200℃. It has
long - term use without deformation and cracking.
Sealing: The seal between furnace door and furnace body and bogie is more important.
The seal between furnace door and furnace body adopts spring compression structure.
The seal between bogie and furnace body is seal of special-shaped brick and fiber
cotton block.
2.5 heating element
heating element: The 0Cr27AL7Mo2 resistance spiral-shape alloy resistance strips
are mounted in 5 side walls, two side walls, back wall, furnace door and bogie bottom.
The resistance strips are produced through special molds, and are installed in the
furnace wall by porcelain nails. And there is a porcelain gasket between the fiber wall
and the resistance strips to avoid short-circuit. There are 1 heating zone. All lead-out
conductor bars are made of φ16 0Cr27AL7Mo material.
2.6 electrical control system
Temperature control: the furnace adopts intelligent temperature controller to control
the temperature which has self-tuning function to calculate the ideal PID parameter
and achieve a temperature stability. The temperature controller has the functions of
over-temperature alarm and thermal couple breakage protection.
The furnace has 1 temperature control zone for controlling the linkage between the
temperature and the motor movements. Each zone is set with an over-temperature alarm.
The heating loop adopts the double-direction SCR and trigger control. The power is regulated
in the time proportional regulation manner.
The control actuation system is a large-power triggering one complete with a radiator and
an air cooling system. There is also an air switch. The heating loop is equipped with
ammeter, voltmeter, heating element on-off indicator, power-on interlock protection,
and safe earthing measures.
Movement control: The control system mainly controls the door up-down movement,
door compression, and door in-out movement. Also the movements are necessarily
linked to ensure the operation safety.
