US 3588067 A
Description (OCR text may contain errors)
United States Patent Primary Examiner-Gerald A. Dost Attorney-Flynn and Frishauf ABSTRACT; A control apparatus for blast furnace operation comprising an infrared video monitor for receiving output image signals obtained by picking up the image of a pattern of heat rays radiated from the top portion of a blast furnace charge using an infrared vidicon camera and detecting the condition of a stock line and gas streams at the furnace top, a monitor of temperature distribution pattern for receiving output image signals from the vidicon camera and indicating a pattern of temperature distribution at the furnace top in the corresponding hues, a data processing device for being previously stored with information on optimum operating requirements related to various furnace conditions and analyzing output image signals from the vidieon camera in comparison with the stored information and a control means for continuously bringing operating factors prevailing within and without the blast furnace to a most suitable condition on the basis of summed up information on output at least from the data processing device, infrared video monitor and monitor of temperature distribution pattern.
PATENTED JUH28 I97! SHEET 3 OF 7 FIG. 3
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SHEET 8 [IF 7 FIG. 8A FIG. 8B
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sum 7 OF 7 FIG. 12A
FURNACE TOP FURNACE I NTER IOR FIGQiZC FURNACE TOP FIG. 12B
FURNACE TOP FURNACE WALL FURNACE CQRE FURNACE WALL FURNACE CORE CONTROL APPARATUS FOR-BLAST FURNACE OIERATION The present. invention relates to a control apparatus for blast furnace operation and more particularly to a control apparatus which involves the use of a data processing device consisting of an industrial television camera and electronic computer system.
As is well known it is of vital importance for blast furnace operation to obtain accurate information on the temperature distribution pattern at the furnace top (particularly that of gas streams) and the height and shape of a stock line charged in the furnace thereby to diagnose the furnace condition and quickly determine an optimum operating process so as to match said condition.
Accurate knowledge of the temperature distribution pattern at the furnace top is indispensable to maintain gas temperature there within s suitable range for proper control of heat exchange between hot gas rising upward through the furnace shaft and falling charged material and also to prevent the occurrence of abnormalities such as ignition of hot gas when its temperature increases over a certain level and the overheating of the structure of the furnace top.
Also information on the exact height and shape of the stock line is very important properly to maintain the residence time of furnace charge so as to control its downward travel and promote necessary processes such as reduction and melting under most favourable conditions.
However, a typical control process for furnace operation heretofore commonly practised only consists in inserting a thermocouple horizontally into the furnace about 1 to 2 metres from that part of the furnace wall which is positioned about 1 to 3 meters above a stock line in order to determine temperature at about 4 to 6 points in the peripheral direction and defining the height and shape of the stock line at about 2 points in the direction of the furnace diameter, using a suitable gauge such as a graduated rod or weight.
However, the aforementioned process of determining the temperature distribution pattern at the furnace top and the height and shape of the stock line was handicapped by the disadvantage of only obtaining information on the measurements conducted at several discontinuous points.
Since furnace operation has heretofore had to be carried out on the basis of insufficient information obtained by determination at such discontinuous points and additionally experimental consideration or findings, it has been next to impossible to keep the blast furnace in an optimum operating condition at all times. Absence of sufficient information often presented difficulties in preventing the occurrence of any abnormal furnace condition when it was expected and setting various factors associated with the furnace operation at optimum values, thus failing to maintain high efficiency production. In place of the aforementioned gauge, there has been proposed a process of determining the height and shape of the stock line from its permeability to radiation from an introduced radioisotope. This process also failed to obtain accurate information as was the case with the aforesaid gauge.
It is accordingly the object of the present invention to eliminate the drawbacks encountered with the prior art processes and provide a control apparatus for blast furnace operation which consists in using an industrial television camera visibly to determine the shape of the whole stock line and the condition and temperature distribution pattern of gas streams at the furnace top continuously and without physically touching them, and also employing a data processing device previously stored with information on optimum operating requirements associated with various furnace conditions so as to bring a blast furnace to an optimum operating condition as quickly as possible.
This invention can be more fully understood from the following detailed description when taken in connection with reference to the accompanying drawings, in which:
FIG. 1 presents a schematic longitudinal sectional view of a blast furnace equipped with an industrial television camera according to the present invention, showing its general arrangement;
FIG. 2 is a schematic block diagram of a control apparatus for blast furnace operation according to an embodiment of the present invention;
FIGS. 3A to 3H indicate the concrete wave forms during operation of the various circuit sections of FIG. 2; 7
FIG. 4 is a more concrete schematic block diagram of the monitor 30 of temperature distribution pattern of FIG. 2;
FIG. 5 is a more concrete circuit diagram of the data processing means Ito 3 of FIG. 4;
FIG. 6 indicates the divisions of an image received bythe aforementioned embodiment;
FIG. 7 shows the wave forms of signals for forming the divisions of FIG. 6;
FIGS. 8A to 8D illustrate typical temperature distribution patterns at the furnace top obtained by picking up an image by the vidicon camera of the control apparatus for blast furnace operation according to the present invention and reproducing it on a picture tube;
FIG. 9 shows gas distribution patterns corresponding tothe temperature distribution patterns of FIGS. 8A to 8D;
FIG. 10A is a sectional view of a concrete means for fitting a vidicon camera to a blast furnace;
FIG. 10B is a plan view of a rotary plate section taken out of the fitting means of FIG. 10A;
FIG. 11 is a sectional view of another concrete means for fitting a vidicon camera to a blast furnace; and
FIGS. 12A to 12C present the typical distribution patterns of raw material located in the blast shaft.
There will now be described an embodiment of the present invention by reference to the appended drawings. FIG. 1 presents a schematic longitudinal sectional view of a blast furnace 11 showing its general arrangement. The furnace is closed at the bottom and comprises an elongated cylindrical wall construction consisting, as mentioned from the top, of a furnace top 13, shaft 14, belly l5, bosh I6 and hearth 17. In a furnace core 18 at the bottom 12 is generally packed coke, and on the sidewall of the hearth 17 section are provided a tuyere l9, cinder notch 20 and tapping hole 21. In the interior of the furnace top 12, shaft 14, belly l5 and bosh 16 above the furnace core 18 are piled up in suitable thickness alternate layers of ore and coke as shown in FIGS. 12A to 12C. FIG. 2 is a schematic block diagram of an entire apparatus for controlling the operation of a blast furnace l1 constructed as illustrated in FIG. 1. The image of a pattern of heat rays radiated from a stock line 22 constituting the topmost portion of the aforesaid pile of ore and coke is picked up by one or two units of the later described infrared vidicon cameras 23 fitted to that portion of the furnace wall above the stock line 22. This arrangement enables image signals corresponding to the height and shape of the stock line and the temperature distribution pattern associated with gas streams in the stock line area to be taken out of the infrared vidicon camera. From the vidicon camera are issued image signals V V corresponding to charged image patterns (not shown) formed on the photoelectric plane of said vidicon by being interposed between the horizontal synchronizing signals I-Is I-Is associated with the raster scanning as shown in FIG. 3A. Output image signals containing the horizontal synchronizing signals l-ls I-Is from the vidicon camera 23 are supplied to a signal processing circuit 25 for cutting signals at a suitable pedestal level Vp adapted to remove the horizontal synchronizing signals I-Is I-Is through a camera control unit 24 consisting of an ordinary amplifier and other elements. Therefore from the output terminal of said'signal processing circuit25 are obtained only the required image signals V V as shown in FIG. 3B. Numeral 26 denotes an automatic control circuit provided, if necessary, to control the vidicon camera 23 by feed back. The circuit 26 is so designed as to detect continuously or intermittently the pedestal level Vp of the signals processing circuit 25 and thereby render the image picking up property of the vidicon camera 23 always stable.
Output image signals from the signal processing circuit 25 are supplied to a video monitor 27 directly to be reproduced as black and white infrared images so as to monitor the height and shape of the stock line 22 and the condition of gas streams at all times, and thereafter to a first and second signal processing circuit 28 and 29. These first and second signal processing circuits 28 and 29 are provided, if required, to cut unnecessary wave forms included in the output image signals V V The image signals V,, V, as shown in FIG. 3B obtained from the first signal processing circuit 28 are supplied to the monitor 30 of temperature distribution pattern having an arrangement detailed in FIG. 4. Where there is good agreement between the level of the image signals V,, V, and the temperature distribution pattern of a heated foreground subject, said signals divide the temperature zone to be determined into a plurality of levels such as R,, R R and R, of FIG. 3B, and pass through a plurality of Schmidt circuits which have set a plurality of isothermal voltage levels T,, T T T and T corresponding to the border lines between the divided temperature levels, for example, at their threshold values. Thereafter said image signals V,, V are supplied to a circuit 41 for generating a composite isothermal voltage pattern Vt consisting, as shown in FIG. 3C, of a plurality of isothermal voltages Vt Vi Vt Vt, having different levels and in consequence collectively presenting a stepped wave form pattern. If it is desired to take out any given isothermal voltage level, for example, Vi it is differentially detected by subtracting other levels, i.e., Vt,, V1 and Vt from the entire composite voltage pattern Vt. Thus there is formed an isothermal image signal pattern comprising, as shown in FIGS. 3D to 3G, a plurality of isothermal voltages Vt V1 V1 and Vt Said isothermal image pattern is presented in high intensity and separate hues on the fluorescent surface of a color picture tube 42 with the respective temperature zones defined by the isothermal lines, or those between T and T between T and T between T and T and between T, and T,. On the other hand, the image signals V V of FIG. 38 issued from the first signal processing circuit 28 are branched ofi' to an A-D conversion circuit 43 to form a temperature distribution pattern by being processed to their time-averaged values and converted to image signals V11 Vd by digital indication as shown in FIG. 3H. These output signals Vd Vd from the A-D conversion circuit pass in turn through the first to their data processing devices 34, 35 and 36 having the later described arrangement and are conducted to a means for indicating pattern of average temperature distribution. FIG. 5 shows the detailed arrangement of the first to third data processing devices 34 to 36. The A-D converted image signals Vd Vd from the A-D conversion circuit 43 are supplied to nine gate circuits G G G G G G G G and G These gate circuits G to G correspond to the divisions of an image indicated on the picture tube as shown in FIG. 6. The component signals corresponding to the divisions of said image are selectively controlled by horizontal gate signals GH GH and GI-l and vertical gate signals GV (3V and GV;,. As illustrated, the image has nine divisions, but it may be separated into any desired number of divisions according to the required precision of determination and processing method for average values. If the gate signals OH, to GV supplied to the gate circuits 6,, to G;,;, are so set as to have timedivided wave forms as illustrated in FIG. 7, signals corresponding to the respective divisions of the image will be taken out of the gate circuits G to G and temporarily stored in the first to ninth memory circuits M to M constituting the second data processing means 45. Signals from the memory circuits M to M are integrated for a given time by a means 48 for obtaining time-averaged values which consists of a counter or the like using, for example, a plurality of R-S flip-flop circuits and are taken out in the time-averaged form. Said signals are further subjected to a digital to analogue conversion by a D-A converter 49 provided, if required, to form image signals denoting the temperature distribution pattern of a heated foreground subject at its prescribed parts. The signals from said D-A converter 49 represent the image signals of said pattern obtained by being picked up by the vidicon camera ill, the momentary values of which were averaged on the basis of a suitably chosen length of time. If said image signals are stored in a video tape recorder 50 (hereinafter referred to as the VTR"), then there will be obtained great convenience in later reproducing and studying a temperature distribution pattern bearing values averaged over a long period.
There is further provided a third data processing device 46, which comprises a voltage signal generating circuit 51 to which there are supplied image signals stored in the video tape recorder 50. Where the levels of the image signals obtained from the data processing means 45 which represent a timeaveraged temperature distribution pattern well agree with the determined temperature of the stock line 22, the aforesaid circuit S1 is arranged and operated in substantially the same manner as the isothermal voltage generating circuit 41 of FIG. 4. Said circuit 51 generateswith respect to a suitably chosen length of time a plurality of average isothermal voltages corresponding to a plurality of average isothermal lines, thereby forming, substantially as in the case of FIGS. 3E to 3G, the wave form patterns of image signals representing isothermal lines averaged with respect to a suitably chosen length of time. Output image signals from the voltage signal generating circuit 51 are formed into color television image signals, in which, for example, the portions interposed between adjacent isothermal lines are distinguished in separate hues by a color indicating mixing circuit 52 formed of the known matrix circuit. Thus on a color television picture tube 47 there is presented a timeaveraged temperature distribution pattern distinguished in separate hues. For example, where the temperature range of a foreground subject is divided into nine parts, the 1st, 4th and 7th temperature zones as counted from the lowest zone are indicated in the three primary colors of a color television apparatus, namely, blue, green and red. And the other zones lying between the aforesaid zones, i.e., 2nd, 3rd, 5th, 6th 8th and 9th are denoted in any two out of the three primary colors of blue, green and red combined in suitable proportion. Accordingly, the actual time-averaged temperature distribution of a foreground subject is shown in the corresponding temperature hue pattern.
Referring to the operating time required for signals to enter the VTR 50, the memory circuit is continuously supplied with information, so that there occurs a dead time for each cycle of computing average values. However, such dead time is of a negligible order as compared with a given time of integration and also checked by a monitor of momentary patterns, so that there is not raised any problem in connection with such dead time. For complete elimination of the dead time, however, it will be advisable to provide another group of circuits in parallel relationship to the original one, and use both groups by turns.
Referring again to FIG. 2, the image signals V,, V of FIG. 33 obtained from the second signal processing circuit 29 are supplied to a data processing device 35 comprising another VTR 31 provided, if required, electronic computer 32 and analyzing means 33 formed of an electronic computer, etc.
To the electronic computer 32 of the data processing device 35 which is stored in advance with information on the optimum operating conditions associated with the furnace top such as the shape of a stock line and the condition of gas streams are supplied image signals V,, V obtained through the VTR 31 from the second signal processing circuit. Where there are also supplied command signals for comparative analysis from a command circuit 34 attached to the electronic computer 32 or analyzing means 33, said image signals V V are analyzed in comparison with the optimum operating conditions associated with the furnace top. Output signals resulting from said comparative analysis and output information signals from a detecting circuit 36 for detecting from the furnace 11 information in connection with the furnace bottom conditions, for example. chemical compositions associated with the temperature of molten metal and slag are supplied to the analyzing means prcuously stored with information on the optimum operating conditions of the furnace bottom. thereby carrying out comparative analysis of the actual operating conditions of the furnace top and bottom and the prescribed optimum operating requirements for these parts ofthe furnace.
Output information signals from the infrared video monitor 27, monitor 30 of temperature distribution pattern and data processing device 35 are fed back, along with information signals from an analyzer 37 of external operating factors including burden, for control of furnace operation to various analyzers, such as those 38 of the primary operating factors 38 related to the raw materials for the blast furnace 11 such as the coke base, conditions in which the armature plate is employed, stock line level, etc, and those 39 of secondary operating factors related to the blower system of the blast furnace 11 such as the volume, temperature, humidity and pressure of blasts and amount ofinjected materials.
A 5 described above, the control apparatus for blast furnace operation according to the present invention enables the furnace operation to be controlled easily as well as continuously to optimum conditions and also the previously mentioned abnonnalities to be readily foreseen and prevented. Namely, the present invention allows any abnormality in the height and shape of the stock line of the furnace charge and gas streams to be observed in the form of an infrared image because a pattern of heat rays generated from the top of the blast furnace 11 by a vidicon camera, and the resultant image signals are supplied to the infrared video monitor 29 through the signal processing circuit 25. Further, the invention permits the momentary and time-averaged temperature distribution patterns of the furnace top to be visually checked using the monitor 30 of temperature distribution pattern and also the operating condition of the furnace to be analyzed by the data processing device 35. Further, the furnace condition can always be analyzed or estimated by summing up output information signals from the infrared video monitor 27, monitor 30 of temperature distribution pattern and data processing device 35. Also the furnace operation can be continuously controlled to optimum conditions by associating data thus analyzed or estimated with the requirements for controlling the primary and secondary operating factors checked by the respective analyzers 38 and 39.
Application of a control apparatus for blast furnace operation according to the present invention arranged as described above to an actual blast furnace (No. l blast furnace of the Tsurumi Plant, Nippon Kokan K.K.) permitted the detection and estimation of abnormal furnace conditions, uniform air permeability in the furnace shaft section, maintenance of optimum operating conditions of the furnace and attainment of very efficient production.
Reference is now made to FIGS. 8A to 8D which present the typical temperature distribution patterns actually observed by the monitor 30 of temperature distribution pattern of the present invention while the aforesaid No. l blast furnace was in operation. The isothermal divisions of these FIGS. represent several groups of temperature: (1) over 500 C., (2) 400 to 500 C., (3) 300 to 400 C., (4) 200 to 300 C. and (5) below 200 C. Namely, FIG. 8A denotes the temperature distribution pattern of said furnace in mean operation, FIG. 8B in wall operation, FIG. SC in inner operation and FIG. 8D in hanging operation. Although such temperature distribution patterns may vary with the manner in which raw materials are charged into the furnace, the various furnace conditions can be estimated by computing a means permeability in the shaft section using the following formula of permeability resistance.
P mean permeability V gas velocity at given point H layer thickness dr Dd (d shape factor; d: particle diameter) v kinetic viscosity of particles 6 void fraction m mean value K K and K constants 10 From the raw material condition and computed permeability index associated with the typical temperature distribution patterns as shown in FIGS. 8A to 8C there are derived Tables 1 and 2 below.
TABLE 1 (ore Intermediate Peripheral Furnace zone zone zone condition (A) 1. 04 1. O2 0. 98 Mean operation. (13).... 1.01 0.99 1.12 Wail operation.
(C) 1.21 0.98 0.94 Inner operation.
TABLE '2 Weight ratio Proportions of raw (ore/coke) Coke base materials, percent Pellets, 30. (A) 3.1 6. 7 t/ch Ore, 30.
i e li 0 9 5, [0 (B) 3 630 1 r, 6 (D) a 2 6.6 40
As apparent from Tables 1 and 2 above, the furnace conditions corresponding to the temperature distribution patterns actually determined by the control apparatus for blast furnace operation according to the present invention well accord with the theoretical values computed by equation 1. If, therefore, a
target temperature distribution pattern is defined in advance and measures are taken to realize the desired operating condition of the furnace, it will be possible to carry out most suitable control, elevate productivity, reduce the ratio of coke to ore and additionally foresee to some extent the occurrence of abnormalities such as hanging operation, blow through, etc. with the resultant maintenance of high operating efficiency.
Further, determination was made of the temperature distribution pattern of gas streams at a point about l.5 meters above the furnace top stock line, the temperature distribution pattern of which was determined as described above, the results being presented in FIG. 9. The curves A, B, C and D of this FIG. correspond to the temperature distribution patterns of FIGS. 8A to 8D.
FIG. 10 illustrates the manner in which the infrared vidicon camera 23 is actually fitted. The furnace wall is bored with an opening 61 for determination. On the outside of the opening 6] is disposed a rotary plate 63 in a manner to rotate around a rotary shaft 62. In said rotary plate 63 are formed three determination holes positioned at the apices of an equilateral triangle with the rotary shaft 62 as the center. All these determination holes are fixed by bolt and nut 65 and sealed by heat-resistant transparent glass material 67 with heat-resistant packing made of, for example, asbestos or silicon rubber allowed to lie therebetween. When any of the determination holes is selectively allowed to face the opening 61 by rotating the rotary plate 63, the remaining two are shielded by blind flange 64. Outside of the heat-resistant glass material 67 is securely set the infrared vidicon camera 23 in a camera case by means of a support cylinder 68 so as to photograph the furnace interior. Numeral 70 denotes a pipe for supplying nitrogen gas for dust purge and cooling. The reason why there are provided in this case a plurality of determination holes is that dust generated in the operating furnace contaminates the surface of the heat-resistant transparent glass material 67 fitted to the detennination hole exposed to the furnace interior with the resultant decrease in the image picking-up capacity of the vidicon camera and that if the determination holes are used by turns in time sequence for removal of said dust, then the vidicon camera will always display a good image picking-up effect.
When the assembly of the infrared vidicon camera 23 is actually fitted to the furnace top, there is used consideration in fully resolving technical problems associated with the deposition of gas dust at the furnace top, cooling means for hot atmosphere, scope of field of vision, etc.
While the number of said cameras to be fitted to the furnace top is suitably determined according to the angle at which it is set in place, the preferred number will be one or two.
FIG. 11 illustrates a vidicon camera assembly additionally provided with a condenser 71. This condenser 71 is supplied with nitrogen gas for dust purge and cooling through a pipe 70, and that part of the heat-resistant glass material 67 which faces the furnace interior is supplied with said nitrogen gas through a pipe 72. It will be apparent, therefore, that the means of FIGS. and 11 may be jointly used in order to operate the infrared vidicon camera 23 under a more suitable condition.
FIGS. 12A to 12C are associated with the case where the control apparatus of the present invention was applied to another blast furnace. In this case, there was formed at the furnace top a peep hole whose maximum field of vision had a horizontal angle of 60 and vertical angle of 50, in a manner as shown in FIG. 10 and there was fitted an infrared vidicon camera to said peep hole. Determination of the temperature of a stock line at the furnace top resulted in the temperature distribution patterns of FIGS. 8A to 8D according to the various furnace conditions prevailing at the time of said determination. Further, from the observation of the shape of the stock line and the data of a sounding meter there were derived the distribution patterns of furnace charge in the shaft section as illustrated in FIGS. 12A to 12C. FIG. 12A represents a distribution pattern in the mean operation of the aforesaid blast furnace, FIG. 128 such pattern in the wall operation and FIG. 12C such pattern in the inner operation. These results prove the aforesaid good permeability of furnace charge controlled by the control apparatus of the present invention.
While the temperature distribution pattern on the surface of the furnace charge, particularly the stock line, could not heretofore be determined unless it was inferred from the measurements of gas temperature conducted at a few discontinuous points or was defined by insertion of a zonde or the like, the present invention now permits such temperature distribution pattern to be determined externally without physically touching the furnace charge over the entire horizontal crosssectional area of the furnace top continuously and at the same time and further momentary changes in the temperature distribution pattern over said cross-sectional area to be followed quickly. Also, the control apparatus of the present invention enables the shape of the stock line to be monitored continuously at the same time the temperature distribution pattern is determined over the entire horizontal cross-sectional area of the furnace top, though said shape was formerly only inferred from the data obtained by inserting a rod gauge or the like.
In addition, the control apparatus of the present invention can be employed in the most desired control processes for elevated efficiency as listed below:
i. determining a continuous temperature distribution pattern of furnace charge over the entire horizontal crosssectional area of the furnace top where there occur changes in the kind and size of raw materials such as pellets, untreated and sintered ores, coke and fluxes; coke requirements per charge, amounts of ore and other auxiliary raw materials to be charged and sequence of their charges; the height of a stock line, shape of a projecting tuyere at the furnace bottom through which there is introduced hot air; and the volume, temperature and pressure of hot air passing through the tuyere;
ii. recording information on the furnace efficiency under the aforesaid conditions, namely, consumption of fuel, tapping efficiency, variations in the composition of tapped product and amount of dust generated and storing a memory device such as an electronic computer with said recorded information properly combined with the related temperature distribution patterns; and
iii. selecting that temperature distribution pattern directly associated with the current operating condition of the furnace and varying according to said pattern the kind, size and amount of raw materials, the sequence of their charges, the height of stock line, and the volume, temperature and pressure of air to be introduced.
Simultaneous and continuous determination of a temperature distribution pattern over the entire horizontal cross-sectional area of the furnace makes it possible to discover the appearance of various undesirable phenomena such as uneven decrease of furnace charge, blow through and hanging, which it was difficult for the conventional control device to find. Accordingly, the control apparatus of the present invention permits the instant application of control processes of varying the above-listed factors so as to obtain an optimum temperature distribution pattern and is also very effective for early discovery of abnormalities. Also procurement of continuous information on the shape and temperature distribution pattern of stock line at the fumace top offers great advantage in properly estimating or controlling the furnace operation for its improvement.
It will be apparent that the control apparatus of the present invention is not limited to the operation of the aforementioned type of blast furnace, but is also applicable to all other general shaft-type blast furnaces including low shaft and cupola types, thus offering great convenience in realizing the optimum operation of blast furnaces in general. Further, the control apparatus of the present invention can be employed in determining the temperature distribution pattern over the horizontal cross-sectional area of a sintering apparatus just before the sintered ore is discharged so as to control its optimum operating process, thereby obtaining high quality product.
l. A control apparatus for blast furnace operation which comprises an infrared vidicon camera for picking-up the image of a pattern of heat rays radiated from the top portion of a blast furnace charge, an infrared video monitor for receiving output signals from said vidicon camera and detecting the condition of a stock line and gas streams at the furnace top, a monitor of temperature distribution pattern for receiving output image signals from the vidicon camera and indicating a pattern of temperature distribution at the furnace top in the corresponding hues, a data processing device for being previously stored with information on optimum operating requirements related to various furnace conditions and analyzing output image signals from the vidicon camera in comparison with the stored information and a control means for continuously bringing operating factors prevailing within and without the last furnace to a most suitable condition on the basis of summed up information on outputs at least from the data processing device, infrared video monitor and of monitor of temperature distribution pattern.
2. A control apparatus according to claim 1 wherein there-is provided one infrared vidicon camera or two disposed in a manner to face an opening formed in that part of the furnace wall which is positioned slightly above the stock line charged at the furnace top.
3. A control apparatus according to claim 2 wherein the infrared vidicon camera involves a rotary plate perforated with a plurality of determination holes fitted with heat-resistant transparent glass material, said holes being opened to the outside of that part of the furnace wall facing the stock line.
4. A control apparatus according to claim 1 wherein the data processing device comprises an electronic computer system.