Gas Fired Car Bottom Bogie Hearth Furnace 4500×1500×1200mm 1150℃

4500×1500×1200mm Gas fired Bogie Hearth Furnace

1. Application

The gas fired bogie hearth furnace is mainly used for heat treatment of

metal parts

2.Structural Introduction

2.1 furnace body

The bogie hearth furnace body steel structure is made from 8# -12#U steel and

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 lining material is 1200℃ high aluminum refractory fibre compacted block.

This refractory lining structure has the advantages of low heat conductivity,

strong anti-shock capacity, and anti-erosion. Aluminum silicate fiber compression

block with thickness of 350mm is designed as the high temperature refractory layer.

2.3 bogie

The bogie hearth furnace manufacturer is comprised of heat preservation

material, bogie frame and moving mechanism. The refractory layer is divided

into 3 sub-layers, i.e., 1st top high-alumina brick layer, and 2nd and 3rd layer

with both light clay bricks.

The bogie framework is made of 16# U-steel and 16# I-steel. The edges of

the bogie are made of 20mm I-steel. The bogie is equipped with 6pieces of

wheels. Each wheel diameter is 300mm.

The heat preservation material is divided into 3 layers, the top layer being

high-alumina bricks, and 2nd and 3rd layer being both light clay bricks.

The bogie hearth furnace supplier is driven by motor reducer gear driving

mechanism. The moving speed of the bogie is 6-8m/min.

2.4 Sealing System

The sealing between the door and the body of the furnace and the trolley is

more critical.

2.5 furnace door

The car bottom furnace price door is comprised of all-fiber lining and steel

structure shell. The door is built with silicate aluminum compressed fiber blocks

same as that for the furnace body. The shell is a welding structure from sectional

steel and steel plates. The furnace door has the feature of simple, practical,

reliable and convenient maintenance. The furnace door is fixed on the bogie.

2.6 burning system

The burning system is comprised of Krom high speed burners, proportional

combustion control system, gas valve, solenoid valve, burner control box, etc.

The burner has the functions of automatic ignition, flame detection, and flame

out alarm. The burner controller receives the control signal of the temperature

controller and controls the large/small fire status of the burner based on the

heat load requirement so that adjustment of the temperature is realized.

A) The burner has adjustment function and the adjustment rate is 1:10 and the

air efficient is 1-5. The burner could meet the temperature uniformity of the heat

treatment process and effectively control the air-gas ratio so that the fuel

consumption is reduced.

B) When the furnace is working, the burning system could automatically cut off

the electrical gas valve and general safety valve in the case of power failure

detected by the alarm system. When the power supply is resumed, the worker

needs to open the safety valve and restart the ignition program after purging

function is confirmed.

The burner is set with a proportional control unit which enables alternative burning

of large and small fire, fire out alarm, and re-ignition. The burner control box has

both manual and self-run modes available. The worker could operate in front of

the furnace or in the control cabinet.

C) The pipe before the burner is equipped with solenoid valve, and manual gas

adjustment valve. The valve system could realize an ideal gas/air supply ratio

so that the air excess efficient is lower than 1.1.

2.6.1 air system

The air piping system is comprised of high pressure centrifugal fan, automatic

regulation valve, pressure gauge and pipes. The air volume is to match the

gas volume, and the air excess rate is lower than 1.20.

2.6.2 gas supply system

The general gas supply pipe is equipped with a pressure regulation device

(equipped with a filter), a low pressure switch and a pressure gauge. For

the sake of safety there is one fast cut-off valve on the general gas pipe.

2.6.3 discharge system

The gas bogie hearth furnace takes direct fume discharge method. The fume

is directly vented out through the flue pipe to the atmosphere. The fume

conducts heat exchange with the heat exchange before emission to the

atmosphere.

2.6.4 Furnace pressure control system

The pressure on the working table in the furnace is kept at (+15 Pa), which is

very beneficial to the uniformity of temperature and the thermal efficiency of

the furnace. When the pressure in the furnace is too high, the hot air in the

furnace will escape from the furnace mouth and other unsealed places, resulting

in the heat loss caused by the escape of the flue gas; because the high

temperature flue gas in the furnace escapes to the outside of the furnace, it will

affect the door, the side seal and burner of the furnace directly, which is related

to the overall service life of the furnace; when the pressure in the furnace is too

low, a large number of cold air outside the furnace will be absorbed into the furnace,

as well. The heat loss of off-furnace flue gas is increased. The low pressure of the

furnace causes the diffusion of cold air outside the furnace into the furnace, and

secondary combustion is formed due to the entry of oxygen-containing cold air,

which has adverse effects on the uniformity of furnace temperature, oxidation of

workpiece and thermal efficiency of the furnace. Therefore, effective technical

measures must be taken to control the furnace pressure with full automatic control.

Our method is to control the furnace pressure effectively by using a system consisting

of pressure taking device, pressure transmitter, intelligent instrument and so on. The

furnace pressure is controlled in the optimum state (the surface of the trolley is in a

slightly positive pressure). At this time, the exhaust gas is in a dynamic equilibrium

state, which can not only ensure that the furnace gas does not overflow, but also ensure

that the cold air outside the furnace is not sucked into the furnace, so as to save

energy and maximize the efficiency of the furnace.

2.6.5 Heat exchange and flue system

A flue is set at the back of the furnace, and it is carried out with the heat exchanger

(according to the national standard GB3486-83). The flue leads to the outside of the

factory building. The cold air is exchanged with the heat exchanger to preheat the

combustion-supporting air before entering the burner, so as to improve the heat

efficiency of the furnace.

Heat exchangers and flue gas exhaust pipes are insulated by internal insulation

(using fiber castables) to ensure the service life of heat exchangers and flues.

2.6.6 fault detection and alarm system

The fast quenching heat treatment furnace has a complete fault detection, alarm,

diagnosis, and safety protection system. On the control cabinet there is an alarm lamp.

2.7 control system

control system has the following parts: Ⅰ. Burning control system; Ⅱ. Electrical

power control system; Ⅲ.temperature control system .

Measures taken for burning control system:

K type thermal couple gets mV signal and sends it to temperature PID controller

(SHIMADEN brand). The temperature controller calculates the signal and outputs

4-20mADC control signal to the electrical actuator. The actuator further sends a

signal to the burner controller after calculation.

The burner controller is mainly responsible for ignition and flame detection. When

the terminal receives the ignition signal, the burner controller carries out flame

simulation and self testing stage. If during this simulation and self-test stage the

burner couldn’t detect the flame signal. The burner controller would open the

gas solenoid valve and convert the voltage 220VAC to 5KV for ignition (ignition

time about 3S). If the burner detects the flame signal in the safe time period

(about 8S), the yellow indication light of the burner would be on (ignition successful).

If the burner couldn’t detect the flame signal, the red light would be on (ignition failed).

The burner controller is locked and the gas solenoid valve is cut off.

B) electrical power control system: The electrical power control system mainly

controls ON/OFF of the fan, and IN/OUT of the bogie.

C) temperature control and record system

The system has the functions of temperature setup, control and digital display.

And also there is an audible and visual alarm at over-temperature situations.

Temperature control zone arrangement

A:temperature control system

The furnace is equipped with 2 thermal couple and an intelligent temperature

controller. The furnace is controlled by 2 zones.

B: instrument temperature control

The temperature controller allows setup of heating time, holding time, and cooling

time. It has self-tuning and self-adjustment function, and displays SV and PV.

3. Main Technical Parameters