3.Structural Introduction
The RT3-1000-12 bogie hearth furnace is mainly comprised of furnace
shell, lining, furnace door and door compression system, bogie,
heating
element and fixed device, and temperature control system.
3.1 furnace shell
The car bottom furnace body steel structure is made from
10-14# sectional steel and ≥3mm 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.
3.2 lining
The industrial heat treatment furnace body 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 1300℃.
The fiber fasteners are made of stainless steel.
3.3 furnace door and door up-down system
The car bottom furnace door is comprised of all-fiber lining and
steel
structure casing. The furnace shell is made of 14# plate and 14mm
steel plate for
the door frame. 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 self-weight of the
furnace door.
3.4 bogie
The bogie is comprised of bogie frame, wheels, refractory
bricklaying body, heat
resistant bogie hearth plate, heating elements, and bogie driving
mechanism.
bogie structure: the bogie frame is made from 18# beam and 14mm
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
pairs of wheels, and each
wheel is of diameter 300mm. The bogie is motorized. And the driving
motor is equipped
with a braking speed reduction device to relieve the inertia at the
start-up and stop
movement. There are 2 limit switches to avoid over-travel of the
bogie.
bricklaying body: The bogie is built with a heavy combination of
high alumina
refractory bricks, light refractory bricks, and heat preservation
bricks. 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 hearth plate: 30mm thick Cr25Ni20 heat resistant steel
casting part with max
working temperature≤1250℃. It can prevent scales from falling into
the heating elements
slot which would form a short circuit.
bogie moving mechanism: The bogie has a self-moving method. The
reducing gear drives
the bogie wheel to move. The bogie movement is smooth and stable.
Sealing among furnace door, furnace body and bogie: Sealing between
the furnace door
and the furnace body is through spring. The sealing between the
bogie and the furnace
body is through soft special shape bricks and fiber cotton block.
3.5 heating element
heating element: The 0Cr27AL7Mo2 (HRE)resistance spiral-shape alloy
resistance strips
are mounted in 2 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 6 heating zones. All lead-out
conductor bars are made of φ16 0
Cr27AL7Mo2 material.
3.6 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 6 temperature control zones 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.
