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Catalogue of developments

Catalogue of developments/COMPLEX OF TECHNOLOGIES FOR TEMPERATURE CONTROL/2.Continuous temperature control
2.4 Light-guide temperature control of metal melts directly in metallurgical aggregates

2.4.1 Light-guide thermometry technologies - description


 The technologies are purposed for the technical realization of continuous light-guide temperature control of closed objects. For example, they provide continuous, during lining life, temperature control and regulation of metal melts under slag in metallurgical furnaces and aggregates. The technologies can also be used for temperature control of salt and ceramic melts, gaseous media and lining, the boundary of liquid and solid metal and other technological parameters

Operation principle

  It is based on the light-guide generation and transmission of heat radiation through the aggregate lining (wall). The radiation has thermometric characteristics synonymously coherent with the temperature of the controlled object. The light-guide unit, stationary mounted in aggregate lining (wall) performs generation and transmission of heat radiation. The main element of light-guide unit is cylindrical light-guide with straight faces, which provides optical contact between primary pyrometric transducer and controlled melt.

Main tеchnical characteristics

Range of measuring temperatures, °С 600...1800.
Measurement error, % ≤0,5.


  As a distinct from known solutions, the technologies, for the first time in world practice, provides continuous high-accuracy temperature control of closed type objects, including metal melts under slag in metallurgical furnaces and aggregates. For example, the measurement errors of liquid metal temperature in the induction crucible and channel melting, holding and pouring furnaces do not exceed 6,4; 4,9 and 4,3 °C, respectively within the temperature range from 1260 to 1600 °C.

Теchnical-economic efficiency

  The technologies provides continuous control and optimal operation of technological processes temperature regimes, including metallurgical processes of liquid metal obtaining, treatment and pouring. For example, during LGTS application on the industrial furnaces ICHT-10, we achieved a remarkable practically double reduction of the energy consumption to 434 kW*h for melting and overheating to 1400 °C of 1 t of cast iron.

Patent protection

  The technologies protected by copyright certificates and patents, as well as by 34 patents in Australia, Bulgaria, Germany, Great Britain, Canada, USA, Sweden and Japan.

2.4.2 Light-guide thermometry technologies under industrial conditions

Operation scheme of the light-guide thermometry technologies.

Main elements of the the light-guide thermometry system.

Construction of the light-guide unit (LGU).

Placement of the light-guide unit in hearth of induction crucible melting furnace.

Immersion end of the LGU in hearth of induction crucible melting furnace.

Mounting of the LGU in a side wall of induction crucible melting furnace<./strong>

The outer part of the LGU in induction crucible melting furnace.

LGU on the "cold" and operating induction crucible melting furnace.

Secondary measurement transducer (SMT), measuring registering device and carry-out digital indicator (CDI) on the induction channel copper-melting furnace.

Cooling unit (CU) on the induction crucible melting furnace.

CU on the induction channel mixering furnace.

CDI on the induction crucible furnace.

2.4.3 Technical-economical indices of exploitation of continuous light-guide temperature control in metallurgy

LGU and CU on the induction channel copper-melting furnace

Light-guide temperature control on the induction channel mixering furnace.

LGU on the induction pouring furnace.

Continuous temperature control of liquid metal in induction channel melting, holding and pouring furnaces

  On the base of modern optoelectronic, fiber, microprocessor and computer technologies, as well as new ceramic materials the light-guide thermometry technologies have been developed. The technologies are purposed for continuous control, registration and regulation of the metal melts temperature in the induction crucible and channel melting, holding and pouring furnaces.
  Light-guide thermometric systems are included in construction of induction furnaces. Developed on the basis of continuous temperature control processes and algorithms for receipt and processing liquid cast iron, algorithms and principles of management of the melting, mixering and pouring of metal are used by machine building branches in production control system (PCS) Electro-melting. Developments are used in branch instructions, which represent automatic production lines, specialized shops and technological processes of receipt, processing and pouring of liquid cast iron in foundry production.
  Economy is achieved mainly due to the reduction of spoilage level and consumption of electricity, fuel and charge materials, increasing lining life duration of metallurgical equipment, exception of failures caused by uncontrolled overheating or overcooling of metal.

Installation of light-guide thermometry system on the heating furnace (Japan, RDC of the NSC)

  Industrial tests of light-guide technology confirm the high efficiency of the light-guide thermometry for continuous precision high-temperature measurements in heating furnaces. For comparative periodic short-term temperature measurements in the heating furnace, the reference thermoelectric thermometer with S-type nominal static characteristic was used. Differences between the indications of the light-guide system and reference thermoelectric thermometer have not been established.

Continuous temperature control of steel in tundish

Continuous temperature control of converter process (joint project offer)

  In terms of technical-economical efficiency and complexity, the TOP-application of continuous temperature control in metallurgy is the convertor process. According to estimates of Western and Japanese experts, 1,5-2,0 billion USD has already been spent in the world on the development of continuous temperature control of the convertor process. Nevertheless, this problem has not yet been solved. According to the same information, our light-guide technology is the closest, among all known developments, to the solution of this global metallurgical problem. The main part of light-guide technology (optoelectronics, algorithms of primary pyrometric information processing and auxiliary devices) has undergone extensive tests under metallurgical conditions and is ready for continuous temperature control of the convertor process. To use this technology on the convertor, it is neccessary to adapt light-guide unit to the converter process conditions on base of modern thermal insulation materials, ceramics and nanoceramics.

© Leonid F. Zhukov. 2007-2023