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Furnace Charge Surface Monitoring Feasibility Scheme
Yoseen infrared is a company focusing on the R & D, production and sales of temperature - measuring infrared thermal camera. Our thermal cameras are widely used in human body temperature measurement, metallurgy, power system, security and other fields.
System introduction

1. Industry Overview

Blast furnace is made of steel as the furnace shell, the shell lined with firebrick. Due to the advantages of good technical and economic indicators, simple process, large production capacity, high labor production efficiency and low energy consumption, this method accounts for the vast majority of the world's iron production. During the production of a blast furnace, iron ore, coke and slag flux (limestone) are loaded from the top of the furnace, and the preheated air is blown from the tuyere located at the bottom of the furnace along the circumference of the furnace. At high temperature, the carbon in coke (some blast furnaces also spray coal powder, heavy oil, natural gas and other auxiliary fuels) is burned with the oxygen pumped into the air to generate carbon monoxide and hydrogen. In the rising process of the furnace, the oxygen in iron ore is removed, so as to reduce the iron. The molten iron is discharged from the mouth. Un-reduced impurities in iron ore combine with flux such as limestone to form slag, which is discharged from the slag mouth. The gas produced is discharged from the top of the furnace and used as fuel for hot air furnace, heating furnace, coke oven and boiler after dust removal. The main products of blast furnace smelting are pig iron, blast furnace slag and blast furnace gas.

2. Industry Application and Pain Points

With the continuous progress of iron-making technology, the operation and control level of blast furnace is also constantly improving. It is required to evaluate the furnace condition quantitatively according to the changes of smelting process. In the normal production of blast furnace, the interaction between the rising movement of gas flow and the falling movement of charge constitutes the burden surface, and the shape of the charge surface is the objective result of the contradictory and unified movement of gas flow and top distribution, and it is also an important basis for material operators to judge the distribution of gas flow and control the smelting process of blast furnace. For a long time, only after the wind rest open the top of the furnace to directly observe the static state of the material surface. In normal production, the distribution of gas flow in furnace can only be judged by the comprehensive analysis of monitoring parameters of furnace body. However, the blast furnace is a large closed high temperature convection reactor, and the factors affecting smelting are complex

The temperature of the material surface in the blast furnace is below 800℃. Under the production condition, there is no visible light in the furnace. Even with the addition of light source, visible light cannot penetrate the environment of high dust and humidity in the blast furnace. Because of the narrow space on the top of the furnace, it is necessary to develop a special wide-angle lens to observe the whole material surface. Due to the furnace top gas seal on the rising tube, material ruler and other technological devices, available space is limited, the camera equipment must be miniaturized.

3. Infrared Thermal Imaging System

Infrared thermal imager uses infrared detector and optical imaging objective lens to accept the infrared radiation energy distribution pattern of the target to reflect on the photosensitive element of infrared detector, so as to obtain infrared thermal image. Different colors on the thermal image represent different temperatures of the object to be measured. The non-contact temperature measurement method of the infrared thermal imager can measure the real time temperature without affecting the work of the roller and take cooling measures at any time. The principle of infrared thermal camera: All objects with temperatures above absolute zero (-273℃) in nature emit infrared rays (or thermal radiation), which are widespread in nature. The atmosphere and clouds absorb visible and near-infrared light, but are transparent to 3-5 microns and 8-14 microns. Therefore, these two bands are called "atmospheric Windows" of infrared. With these two Windows, we can get a clear view of what is ahead on a completely dark night or in a thick cloud of smoke. Using infrared thermal imaging technology to observe the situation in the blast furnace can effectively solve the furnace no visible light, high dust, high humidity environment clearly display the situation. Based on the technology base, Yoseen Infrared has been developed specially for the optimal letter technology co., LTD specially used for burden surface monitoring of infrared thermal imaging system, the system is a kind of installed on the blast furnace top, through the hole to real-time continuous monitoring of furnace production situation, on the control of indoor monitor can within the furnace on the distribution of the material surface, material layer combustion situation in real time observation, real-time and accurate for the blast furnace operators make more correct and scientific judgment and decision-making, improve the production efficiency.

Schematic diagram of infrared monitoring system for furnace charge surface


The whole system is composed of special infrared thermal imager, protective cover and transmission protection device, network wire transmission system, background display system and software.


3.1 special infrared thermal imager, according to the requirements of high burden surface observation we special produce the small aperture pinhole camera, through the thermal imager in blast furnace roof opening into the hole on the condition of the furnace monitoring, large field of view Angle of pinhole lens can not only ensure the scope of the observation can also reduce the risk of material churning the lens damage.


Special infrared thermal imager for blast furnace


3.2 Protective cover and transmission protection device

3.2.1 The pure air cooling technology of the protective cover adopts forced air cooling, which is simple to use, easy to maintain and not subject to regional restrictions. The cooling technology is used to ensure the normal operation of the system as a part of the air source for the blowing lens. According to the scientific design of airflow distribution, the rotating air curtain is formed in front of the lens, which increases the intensity of the air curtain and the area of blowing, and effectively prevents the dust and lens objects in the furnace


3.2.2 The overall structure of the transmission protection device is made of special high-temperature resistant stainless steel material, so it has high strength of high-temperature resistance and corrosion resistance. Based on the original technology, it adopts mold design, which makes the device beautiful in appearance, compact and light. The transmission part adopts high-precision metal guide rail transmission, and adopts self-locking motor as the power, the movement is flexible, which overcomes the traditional screw nut structure is easy to deformation stuck, the whole system structure is simple, compact, delicate, light weight. It can be used for both electric and manual operation to make the device reach in and exit smoothly and reliably. Manual push and pull the probe cover or press the push button on site, exit button and operator in the control room can both conduct remote control on the entry and exit of the thermal imager. When the compressed air pressure is lower than the set value ≤ 0.1mpa, or when the internal temperature of the thermal imager is higher than the set value ≥55℃, or when power is cut off (UPS power is required), the thermal imager can automatically exit the furnace, and the observation hole will automatically close and send an alarm signal. Temperature control adopts digital display, and the upper and lower limits of temperature control can be set in advance to realize over-temperature alarm.


3.3 The thermal imager of the network cable transmission system has a standard network interface, which can be transmitted through the network cable or optical fiber according to the site environment. The screen of the front-end thermal imager can be connected to the back-end computer software for staff to observe and record.


In the process of regional temperature analysis, the local temperature can be displayed by adding a temperature measuring object. The temperature measuring objects that can be added include point temperature measuring object, line temperature measuring object and polygon temperature measuring object.

After adding the temperature measuring object, the characteristic temperature of the temperature measuring object will be displayed, such as the highest temperature, the lowest temperature, the average temperature, etc., which is convenient for local analysis.


3.4.2 Unique DDE detail enhancement algorithm Aiming at the high temperature and high dust environment in the blast furnace, in order to solve the problem of clear image, for the monitoring system software of the blast furnace infrared thermal imager, we adopt a unique DDE detail enhancement algorithm, which can remove the influence of dust and flame and see the material surface clearly and intuitively.

4. Summarize


Wuhan Yoseen Infrared Technology Co., Ltd. has developed this monitoring system of infrared thermal imager for the image of furnace charge surface through years of accumulation and combined with complex working conditions on site. Through the temperature measurement of infrared thermal imager imaging characteristic solved inside the blast furnace sealed environment effectively through visible light observation problem, at the same time, using small aperture pinhole camera solve the problem of the blast furnace roof installation space is limited, at the same time through the air-cooled refund bore shield and automatic protection device to ensure thermal imager front working environment temperature, when the temperature anomalies in a timely manner will pop-up equipment, ensure the safety of the equipment. The unique DDE detail enhancement algorithm eliminates the influence of smoke and flame in the furnace, making the imaging picture sharpness of the furnace charge surface to a higher level, which has been recognized and praised by customers in the industry, providing great help for improving the iron making technology and efficiency.

technical parameter

It is a series of special thermal camera for metallurgy industry, small size and easy to install; clear image and wide temperature measurement range; high sensitivity, run stably in complex environment; small entrance, parts replace easily, low repair cost;professional industry monitoring software, complex business can be carried out
  • High sensitivity, run stably in complex environment
  • Small entrance, parts replace easily, low repair cost
  • Professional industry monitoring software, complex business can be carried out

Product Applications

Blast furnace burden surface, steel ladle, converter monitoring and others in harsh environment






Infrared resolution




Pixel size


Frame frequency



Working band


Field angle

100°* 78°, diagonal 115 °

Temperature range

80~800℃, 160-1600℃ (customizable)

Temperature accuracy

±2℃ or ±2%, can be raised to ±0.4℃





Imaging distance

About 20 times focal lengths to infinity

Temp measuring template

Global high and low temp tracking, point/line/rectangle/ellipse temp measuring template, and tracking in template

Image enhancement

Adaptive drawing, manual enhancement, electronic zoom

Color palette

White hot, black hot, iron red, red saturated, user-defined and others


Focus Mode

Electric/manual, electric lens supports autofocus


Single frame temp

PNG / BMP/ JPG image format with temperature information


Temperature flow

Total radiant temperature information storage

Digital video

H.264, RTSP stream media protocol, MP4 files, HDMI output interface

Electrical interface

Power supply

DC9~15V, typical power consumption 2.5W@25℃

Analog video

NTSC/PAL compound video output 


100/1000 Base, TCP, UDP, IP, DHCP, RTSP, ONVIF, etc.,provide SDK development kit

Environmental parameters


Non - Condensing 10%~95%

Temp range

Operating temp: -10~+60℃, Storage temp: -40ºC~+85℃

Level of protection

IP54, Impact resistance: 25G, Vibration resistance: 2G 



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