Method and apparatus for automatically punching the tuyeres of a converter

Method and apparatus for punching the tuyeres of a converter with a mechanical puncher mounted upon a carriage running on rails. Light intercepting plates encoded by light transmission holes are disposed opposite each tuyere. Light is shone towards the light intercepting plates and detected on the opposite side thereof by photoelectric elements the outputs of which are coupled to a digital processor which controls the speed and position of the carriage. The mechanical puncher has two cylinders each of which drives two punching rods to successively punch the tuyeres. If it is impossible to punch a tuyere with the mechanical puncher were moving in one direction, the position of the puncher is shifted by one tuyere to start the punching again in the opposite direction.

BACKGROUND OF THE INVENTION 
The invention relates to a method for automatically punching the tuyeres of 
a converter. 
Converters are extensively employed for smelting metals. In smelting copper 
with a converter, air is blown into a matte containing 40% to 60% copper, 
and the remaining contents, iron and sulfur, are removed by converting 
them into iron oxides and sulfur dioxide so as to obtain blister copper 
containing about 98% copper. The air blowing nozzles are relatively small 
in diameter, typically several tens of millimeters. Molten materials in 
the converter is solidified and form encrustations at inner tips of the 
tuyeres by adiabatically cooling the molten materials with blowing air. In 
this case, it becomes difficult to supply sufficient amount of air into 
the converters, as a result of which the converting operation must be 
suspended, when the solidified encrustations has been grown up. Therefore, 
mechanical punching operation is carried out in order to remove the 
solidified encrustations frequently. 
Heretofore, an operator seated on an operator's seat on the carriage of a 
mechanical puncher having punching rods coupled to a fluid-driven cylinder 
visually confirmed the positions of the tuyeres of a converter and 
controlled the running and stopping of the carriage to achieve a punching 
operation to clear the nozzles. Accordingly, the punching operation could 
not be accomplished without considerable operator skill. Furthermore, with 
a mechanical puncher having four punching rods driven by a single cylinder 
in order to reduce the time required for punching operation, much higher 
skill is required for the operator to accurately position the carriage 
correctly with respect to the intended tuyeres. The working environmental 
conditions around the converter are poor because of the presence of noise, 
heat, dust, etc. In addition, there is the danger that the converter may 
"foam", that is jet out high-temperature molten materials. The provision 
of a method for automatically and positively punching the tuyeres and an 
apparatus for practicing the method has been strongly demanded in the art. 
Accordingly, an object of this invention is to provide a method for 
automatically, positively and safely punching the tuyeres of a converter. 
SUMMARY OF THE INVENTION 
In accordance with this object, a specific advantageous feature of the 
invention resides in that an AC variable speed motor with a brake is 
employed to run a mechanical puncher carriage on the rails so that the 
carriage is run and stopped quickly and positively. A non-contacting type 
position detecting device having detectable elements and a control device 
for processing signals outputted by the position detecting device are used 
to quickly and positively detect the positions of the tuyeres and to 
automatically punch the tuyeres. 
Another specific advantageous feature of the invention resides in the 
travel of the carriage which mounts mechanical puncher. That is, according 
to the present invention, since a pair of punching rods are simultaneously 
driven by a single cylinder, if hard or rigid encrustation is formed in 
one of the tuyeres, the neighbouring tuyere can not be subject to punching 
during travel of the carriage in one direction along the converter. In 
this case however, during opposite travelling of the carriage, the 
carriage is initially shifted by one tuyere to start the punching 
operation, so that said unpunched tuyere can be punched. The tuyere formed 
with rigid encrustation can be punched manually or other suitable 
mechanical means so that all of the tuyeres are punched. Also, before the 
tuyeres are punched, the position or posture of the mechanical puncher is 
adjusted in conformance with the displacement of the tuyeres which are 
changed according to operational requirements of the converter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The invention will be described with reference to the accompanying 
drawings. 
FIG. 1 is a side view, partly in longitudinal section, of a converter 1. 
Compressed air is supplied to tuyeres 2 through corresponding flexible 
tubes 4 coupled to the nozzles of a header 3. FIG. 2 is a sectional view 
of an essential part of the tuyere 2. When solidified encrustations 2a are 
formed in the tuyere 2, they can be removed by inserting a punching rod 5 
into the converter 1 through the tuyere 2 through a closing mechanism of 
the tuyere, here simply a ball in the open position. 
FIG. 3 shows a section taken along line A--A in FIG. 1 and the positional 
relationship of a mechanical puncher 12 constructed according to the 
invention. The mechanical puncher 12 is so designed that it may be tilted 
and displaced vertically and horizontally by means of a link drive device 
13 and turning arms 14. 
The invention will be described with reference to the case where the 
element to be detected is a light intercepting plate and the 
non-contacting type detector used is a photoelectric tube device. However, 
it should be noted that the invention is not limited thereto or thereby. 
That is, a detecting iron piece may be employed as the element to be 
detected and a contactless switch may be employed as the non-contacting 
type detector. 
A number of light intercepting plates 7 as shown in FIG. 1 are provided 
which are equal to the number of tuyeres, as shown, 48 of each. The upper 
and lower end portions of each light intercepting plate 7, provided at a 
position corresponding to the respective tuyeres, are held by belt-shaped 
plates 9a and 9b, respectively, which are fixedly secured to posts (not 
shown) provided in the vicinity of the ends of the converter. 
FIG. 4 is a front view showing the arrangement of a photoelectric tube 
device 10 and light intercepting plate 7 used with the invention. FIG. 5 
is a sectional view taken along line B--B in FIG. 4. 
Light emitting units 10a and light receiving units 10b are provided on both 
sides of the plate 7 in such a manner that the light emitting units 10a 
accurately confront the corresponding light receiving unit through the 
plate 7. The light emitting units produce non-diffused light beams. The 
light receiving units are preferably photoelectric tubes. The light 
emitting units 10a and the light receiving units 10b are fixedly mounted 
on the mounting plates 10c of a frame 10d in such a manner that the units 
10a are positioned along a single vertical line and are arranged at equal 
intervals, and the units 10b are similarly positioned along a single 
vertical line at equal intervals. 
The light intercepting plate 7 provided as a thin metal plate 150 mm in 
width and 520 mm in length, for instance. The plate 7, as shown in FIG. 6, 
has a group S of spaced holes in the form of rectangular slits and cuts, a 
group P of position holes formed as a plurality of rectangular slits which 
are used to determine the position of the corresponding tuyere and 
mounting holes 11. The light emitting units 10a and the light receiving 
units 10b are arranged on common axes and the axes of the units are the 
same level as horizontal lines passing the centers of the rectangular 
slits. 
A preferred method for punching the tuyeres of a converter according to the 
invention will now be described. 
The converter is rotated according to operational requirements and 
accordingly the level of the line of tuyeres is displaced. Prior to the 
tuyere punching operation, the position of the mechanical puncher is 
changed by operating the link drive device according to the displacement 
of the tuyeres. As a result, the central axis of the punching rod of the 
mechanical puncher is brought into coincidence with the central axis of a 
tuyeres no matter what the operational requirements of the converter 
whereby the punching of the tuyeres can be achieved smoothly. 
First, the case where the tuyeres are selectively punched will be 
described. A tuyere to be punched is set in a control device (not shown). 
Upon instruction of the start of operation, the carriage of the mechanical 
puncher is run with its run drive motor (not shown). While the carriage is 
being run, the numbers of the tuyeres are successively detected. When the 
tuyere of a number smaller by one than the number of the desired tuyere is 
detected, the speed of the carriage is automatically reduced. Then, the 
light receiving unit, the uppermost unit, detects the timing light 
transmission hole t.sub.1 of the light intercepting plate corresponding to 
the desired tuyere whereupon the carriage is braked to a stop. This 
operation will be referred to as "step t.sub.1 " hereinafter. The run 
drive motor is preferably an AC variable speed motor with a brake the 
speed of which can be readily controlled. 
If the carriage has run beyond the center of the desired tuyere, the 
over-run is detected by the light receiving unit corresponding to the 
light transmission cut t.sub.2. The control device provides an instruction 
signal to return the carriage to the center of the desired tuyere. This 
operation will be referred to as "step t.sub.2 " hereinafter. 
If in the return the carriage is moved too far, the fact of excessive 
return is detected by the light receiving unit corresponding to the light 
transmission cut t.sub.3 and the control device outputs an instruction 
signal to return the carriage to the center of the desired tuyere. This 
operation will be referred to as "step t.sub.3 " hereinafter. 
Usually, the carriage positioning operation is achieved in step t.sub.1 or 
in step t.sub.2 and the carriage stopped at the intended correct position. 
That is, in practice, step t.sub.3 is most often unnecessary. 
Once the carriage has been accurately positioned, the number of the desired 
tuyere is confirmed by a combination of the group of position holes or 
light transmission slits P.sub.1 through P.sub.6 and an instruction is 
applied to the mechanical puncher to start the punching of the desired 
tuyere. 
A parity light transmission slit 0 is used as an error detecting hole. The 
slits in the group P correspond to 2.sup.0, 2.sup.1, 2.sup.2, 2.sup.3, 
2.sup.4 and 2.sup.5 respectively beginning with the uppermost slit. That 
is, the slits represent numbers 1, 2, 4, 8, 16 and 32, respectively. For 
example, a light intercepting plate 7 having the slits 2.sup.0 and 2.sup.1 
is provided for No. 3 (2.sup.0 +2.sup.1 =3) tuyere. Similarly, a light 
intercepting plate 7 having the slits 2.sup.1 and 2.sup.3 is provided for 
No. 10 tuyere and a light intercepting plate 7 having the slits 2.sup.0, 
2.sup.1 and 2.sup.3 is provided for No. 11 tuyere. Upon completion of the 
punching of the desired tuyere, the carriage is moved to the next desired 
tuyere. 
The dimensions of the light transmission holes in the example given here 
are w.sub.1 =50 mm, w.sub.2 =15 mm and w.sub.3 =110 mm as shown in FIG. 8 
so that the carriage can be stopped with an error of .+-.15 mm with 
respect to the center of an aimed tuyere. Thus, the carriage can be 
automatically stopped at a position suitable for punching a tuyere. 
However, it should be noted that the dimensions of the light transmission 
holes are not limited to these particular values. 
Next, the case where the forty-eight tuyeres shown in FIG. 1 are 
successively and continuously punched will be described. FIG. 7 shows a 
part of the tuyeres in FIG. 1 and more specifically the tuyeres No. 1 
through No. 10 in the left end group and the tuyeres No. 44 through No. 48 
in the right end group. In the conventional mechanical puncher, four 
punching rods are driven by one cylinder. In contrast, in the mechanical 
puncher of the invention, two punching rod sets are provided. In each set, 
two punching rods are driven by one cylinder thereby to improve the 
flexibility in punching operation. 
It is assumed that the tuyeres are punched by the two punching rod sets, 
that is, four punching rods beginning with tuyere No. 1. The start of the 
punching of the tuyeres can be commenced by detecting a reduction in the 
amount of air blown through the converter. By way of example, the 
operation will be described with reference to the case where solidified 
encrustations are formed in tuyere No. 8 to the extent that they cannot be 
removed by the punching force of the cylinder. Solidified encrustations in 
the forty-eight tuyeres should be removed by repeating the punching 
operation twelve times (12.times.4 punching rods=48). For this discussion, 
it is assumed that the tuyere No. 7 remains unpunched because it has been 
impossible to punch tuyere No. 8. 
Before the mechanical puncher returns, the position of the mechanical 
puncher is shifted by one tuyere so that the punching operation is started 
with tuyeres No. 47 through No 44. Although the other tuyeres may be 
successively punched, the tuyere No. 9 remains unpunched because it has 
been impossible to punch tuyere No. 8 as described above. Accordingly, 
after the punching operation has otherwise been completed, the tuyeres No. 
48 and No. 9 have not punched. The solidified encrustations in the tuyere 
No. 8 should be removed by other means. The abovedescribed series of 
operations are carried out in response to instruction signals from the 
control device. 
The control of the positioning of the carriage and mechanical puncher is 
accomplished by a control device constituted by a digital processor 
system. In this system, the output signals from the light receiving units, 
speed detector and punching rod position detector are assembled using 
standard data assembly techniques and coupled to data inputs of a digital 
processor. The digital processor then operates to produce the necessary 
control signals to move the carriage to the appropriate positions. The 
operation of the digital processor is in accordance with the flow diagrams 
of FIGS. 9A-9C. 
According to the invention, to selectively punch the tuyeres, the punching 
rod can be correctly set to punch the selected tuyeres and the selected 
tuyeres punched completely automatically. To successively punch the 
tuyeres, the number of the tuyere the punching of which has been 
impossible can be displayed by employing a method in which, when it is 
impossible to insert the punching rod thoroughly into the tuyere, the 
reaction force occurring in the rear end of the punching rod is detected 
and converted into an electrical signal and the tuyeres except those the 
punching of which has been found to be impossible are sequentially and 
automatically punched. 
As the punching operation can be started upon detection of a reduction of 
the amount of air blown through the converter, the punching operation of 
the tuyeres of the converter can be completely automatically accomplished. 
Thus, the invention contributes significantly to safety and to a reduction 
in the number of operators and accordingly to a reduction in personnel 
expenses. Furthermore, according to the invention, the position of a 
tuyere can be readily and positively detected.