1. Application
The RT3-110-11 electric bogie hearth furnace is mainly used for annealing, quenching and normalizing of steel parts, casting parts and stainless steel parts, etc.
2. Structural Introduction
The RT3-110-11 bogie hearth furnace is mainly comprised of furnace
shell, lining, furnace door, furnace door lifting mechanism and door
compression mechanism, bogie, bogie traction mechanism, sealing
between furnace body and bogie, heating element and fixed device,
and temperature control system.
2.1 furnace shell
The electric resistance car bottom furnace body steel structure is made
from 8-10# 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.
2.2 lining
The gas car bottom 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 325mm. The silicate aluminum fiber resists a maximum temperature of
1260℃. The fiber fasteners are made of stainless steel.
2.3 furnace door and door up-down system
The fast quenching heat treatment furnace door is comprised of all-fiber lining
and steel structure casing. The furnace shell is made of 12mm 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.
2.4 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 12mm steel plates and 12# steel
beam. 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 2 pairs of wheels,
and each wheel is of diameter 240mm. 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 ZG35Cr24Ni7SiN heat resistant steel casting
part with max working temperature≤1200℃. 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 self-weight pressure tightening
mechanism. The sealing between the bogie and the furnace body is through
soft special shape bricks and fiber cotton block.
2.5 heating element
heating element: The 0Cr27AL7Mo2 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 1 heating zone.
All lead-out conductor bars are made of φ16 0Cr27AL7Mo2 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.
A. According to the process requirements, the temperature rise program is set in
the intelligent instrument and distributed to each temperature zone for control.
Call and edit the corresponding process, send signals to the lower level, and
collect the temperature of each zone from the upper instrument.
B. When the main power supply is turned on for operation, the equipment will normally
control the electric furnace according to the program process set in the intelligent
instrument.
(2) Power control: it adopts high-power trigger system, equipped with radiator and
a full set of air cooling system. Each group of electric heating elements shall be
equipped with ammeter, voltmeter and on-off indication of electric heating elements,
with power on interlocking protection and safe grounding measures to ensure safe use.
The lifting of the furnace door and movement of bogie are all completed in the control
cabinet. There is reliable electrical interlocking between each action and power on
interlocking protection with the electric heating system.
