JPS624809A - Method for controlling position of lance for addition - Google Patents

Abstract

PURPOSE:To control the relative positional relation between a lance and molten metal level with good accuracy by downward moving a lance insulated and connected at the front end and rear end, detecting the contact thereof with the molten metal and rising the lance at a high speed in accordance with the signal thereof. CONSTITUTION:The front end 20A and rear end 20B of the lance 20 are connected via an insulating flange 22 to constitute an integral construction. The lance 20 is lowered by a vertical driving device 30. The position of the top end 20E of the lance is detected by a pulse generator 72 and a lance position detecting circuit 74 and the result thereof is displayed on a display device 82. A molten iron detecting circuit 76 detects the molten iron surface when the end 20E contacts with the molten iron surface 15. The lance 20 is stopped by the signal thereof and the molten iron level is displayed on the device 82. The once stopped lance 20 is raised at a high speed by as much as the set height by a pole change motor 32 of the vertical driving device 30. The lance 20 is raised at a high speed by as much as the set height by the operation similar to the above-mentioned operation when the molten iron surface 15 rises and contacts the lance 20 again.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for controlling the position of an additive lance, and is particularly suitable for applying an additive to molten metal that has flowed down a tap trough and fallen into a tilting trough, which is suitable for use in desiliconization equipment in a blast furnace cast bed. Position of addition lance for projectile addition 1III11 Method.

[Conventional technology]

In steelmaking facilities, as each process becomes more continuous, reducing the amount of silicon in pig iron in the pig iron making process is considered the most effective means for optimizing the hot metal smelting process in the steel making process. Today, desiliconization equipment is being actively introduced into blast furnace casthouses. This desiliconization equipment has two methods: a top-sprinkling method in which the desiliconizing agent is simply dropped onto the hot metal gutter in the blast furnace casthouse using conveyor equipment, and a top-sprinkling method in which the desiliconizing agent is injected into hot pig iron. There are two types of driving methods (Japanese Patent Laid-Open No. 143010/1983) in which the hot pig iron is injected directly above the hot pig iron in the trough or tilting pipe using a dosing lance. Among these, the driving method using an addition lance in the tilting trough has recently attracted attention because it has advantages such as a reduction in the unit consumption of the desiliconizing agent, suppression of slag foaming, and easy installation. The lance 20 and lance cart 60 of this desiliconizing agent driving method are configured as shown in FIG. 3, for example, and the hot metal falls from the hot metal trough 10 onto the tilting trough 12 as shown by arrow B in the figure. However, after temporarily staying here, the flow becomes injected into the torpedo car on the tilting direction side of the tilting trough 12. The lance 2o can be moved up and down by the vertical drive device 30 on the lance cart 60, can be oscillated in the left-right direction about the fulcrum 20C by the left-right tilting device 40, and can be moved around the fulcrum 20C by the front-back tilting device 50. It has a configuration that allows rocking movements in the front and rear directions with 20D as the rocking center,
Through a comprehensive combination of movements, the tip 20E of the lance 20
is the movement range shown by the shaded area C in the figure. On the other hand, the desiliconizing agent is injected from the upper part of the lance 20 via the flexible hose 24, passes through the hollow lance 20, and is sprayed with compressed air from the tip 20E of the lance 20 against the surface of the hot metal under strong pressure to desiliconize it. The reaction is accelerated. The desiliconizing agent is aimed at the surface of the hot metal immediately after it has fallen from the hot metals 8 and 10, or at the surface of the hot metal that has temporarily stagnated after falling and is about to change its flow direction. Further, the lance truck 60 is configured to raise the lance 20 to the upper limit and retreat when the iron is not tapped. In addition, 70 in the figure is a lance control device.

[Problem to be Solved by the Invention 1] However, when using the equipment shown in FIG. 3 to inject the desiliconizing agent into the hot metal on the tilting gutter 12 using the addition lance 20, the following procedure is required. There are problems. That is, immersing the lance 20 in hot metal must be avoided because the tip 20E of the lance 20 will melt, and from the viewpoint of improving the reaction efficiency of the desiliconizing agent, the lance 20 should be kept at a certain distance from the surface of the hot metal. It is necessary to secure it. For this purpose, it is essential to understand the mutual positional relationship between the tip of the lance 20 and the surface of the hot metal. However, since the desiliconization reaction is very violent and involves a large amount of smoke and dust, it is impossible to monitor visually, and therefore, the tip of the lance 20
There is a problem in that it is difficult to grasp the mutual positional relationship between the 0E and the hot metal surface. Furthermore, the mutual positional relationship between the tip 20E of the lance 20 and the hot metal surface is not always constant, and the hot metal surface level may change due to changes in the tapping speed or changes in the tilting direction and tilting angle of the tilting gutter 12. Fluctuations in the molten metal surface level due to changes, wear and tear of the gutter material of the tilting l1112, and changes in the tip 20 of the lance 20.
It is dominated by many unstable variables such as E wear. Therefore, from the viewpoint of preventing contact with the hot metal surface, preventing collision with the tilting trough 12, and operational aspects, it is necessary to three-dimensionally detect the position of the tip 20E of the lance 20 and to detect the level of the hot metal surface. However, the environment around the tilting gutter 12 is bad, with strong suction wind from the dust collector, splash from the desiliconization reaction, and high temperature.
The problem is that it is difficult to detect the three-dimensional spatial position of the metal and the level of the hot metal surface. Further, although it is important to understand the amount of wear on the tip 20E of the lance 20 in terms of maintenance management, conventionally there is a problem in that it is difficult to properly understand the amount of wear due to the above-mentioned adverse environment. Moreover, since the cast bed desiliconization equipment using additive lances was developed in response to new requirements, it is not possible to provide information on the fil control of the lance 20 used in this equipment or the detection of the mutual positional relationship between the lance tip 20E and the hot metal. Despite this, in reality, the lance 2° The current situation is that it is necessary to carry out silica-free operations. OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to accurately detect the mutual positional relationship between the lance and the molten metal level under severe conditions, and to It is an object of the present invention to provide a method for controlling the position of an addition lance that can appropriately control the addition lance of a driving type cast bed desiliconization equipment or the like.

[Means to solve the problem]

The present invention relates to a method for controlling the position of an additive lance that sprays and adds additives to molten metal that has flowed down a tap trough and fallen into a tilting trough, in which the tip and rear ends are electrically isolated and connected. A lance having an integral structure is movable up and down above the molten metal, and the lance is moved down to electrically detect contact between the molten metal and the tip of the lance. The above objective is achieved by separating the tip of the lance from the molten metal for a predetermined period of time after detecting the lance at a rising speed higher than the descending speed of the lance, thereby maintaining a constant distance between the molten metal surface and the lance tip. It is. Further, in an embodiment of the present invention, the contact between the molten metal and the lance tip is electrically detected by detecting the presence or absence of a weak current in a closed loop including the molten metal and the lance tip. Further, in another embodiment of the present invention, the electrical detection of the contact between the molten metal and the lance tip is performed by electrostatic detection depending on whether or not the lance tip contacts the molten metal in a closed loop including the molten metal and the lance tip. This is done by detecting changes in capacitance. Another practical IM aspect of the present invention is to electrically detect the contact between the molten metal and the lance tip based on the presence or absence of a weak current in a closed loop including the molten metal and the lance tip, and to determine whether the lance tip is melted in the closed loop. This is done by detecting the change in capacitance depending on whether or not it contacts the metal, and when the two detection signals almost match, it is adopted as a detection signal of contact between the molten metal and the tip of the lance. It is something.

[Function 1] The present invention electrically connects the tip and rear ends when controlling the position of the addition lance that sprays and adds additives to the molten metal that has flowed down the tap runner and fallen into the tilting runner. A lance that is insulated and connected and has an integral structure is used so as to be able to move up and down above the hot metal. This allows the lance to be utilized as a moving electrode for molten metal level detection. Moreover, the electrode is molten metal, and the return path is the earth via the tilting gutter.
A book that comes with a book lance! ! By using the rod type, there is no need to use other electrodes, etc., and the configuration can be simplified. The present invention also provides for electrically detecting contact between the molten metal and the tip of the lance by lowering the lance. As a result, it can be used in desiliconization reactions, etc., which produce extremely large amounts of smoke and dust and cannot be visually monitored. It is possible to accurately detect the lance tip position and the level of the molten metal surface, which have high stability fluctuation factors, and to grasp the mutual positional relationship with high precision. Therefore, it is possible to prevent collisions with the molten metal surface and the pouring gutter, and to prevent wear on the tip of the lance. The present invention further provides a method for electrically detecting contact between the molten metal and the lance tip, and then separating the lance tip from the molten metal for a predetermined period at a rising speed higher than the descending speed of the lance, thereby bringing the molten metal surface and the lance tip into contact with each other. I try to maintain a constant distance between them. This improves the accuracy of stopping on the molten metal surface when the lance is lowered and prevents the lance tip from being submerged in the molten metal, and when the lance is raised, it quickly moves away from the molten metal surface and melts the lance tip. losses can be prevented. In addition, electrical detection of contact between molten metal and lance tip is
By detecting the presence or absence of a weak current in a closed loop that includes the molten metal and the lance tip, or detecting changes in capacitance depending on whether or not the lance tip contacts the molten metal in a closed loop that includes the molten metal and the lance tip. By doing this, it is possible to accurately detect contact between the molten metal and the tip of the lance even under harsh environments. Further, the presence or absence of a weak current in a closed loop including the molten metal and the tip of the lance, and the change in capacitance depending on whether or not the tip of the lance contacts the molten metal in the closed loop, are detected, and the two detection signals are detected. By outputting a judgment that the molten metal and the lance tip have contacted each other when they almost match, the reliability of detection is improved by electrically detecting the contact between the molten metal and the lance tip. be able to. In particular, it becomes possible to prevent malfunctions caused by instantaneous splashes from the desiliconization reaction. Embodiments Hereinafter, embodiments of a position control device for a desiliconization agent addition lance to which the present invention is applied will be described in detail with reference to the drawings. In this embodiment, as shown in FIG. 3, a desiliconizing agent addition lance 20 is positioned [1 As shown in FIGS. 1 and 3, the device includes a lance 20 having an integral structure in which a front end 2OA and a rear end 20B are electrically insulated and connected via an insulating flange 22, and the lance 20 is A vertical drive device 30 that moves up and down, a left-right tilt device 4o that tilts the lance 20 in the left-right direction, a front-back tilt device 50 that tilts the lance 20 in the front-back direction, the lance 20, the vertical drive device 30, and a left-right tilt device. Device 40, forward and backward tilting device 50
a lance truck 60 that holds the lance 2'0 and lifts the lance 2'0 to the upper limit and retracts it from above the tilting trough 12 when the iron is not tapped;
The contact between the hot metal 14 and the tip of the lance 20 is electrically detected, and the vertical drive device 30 separates the tip of the lance 20 from the hot metal 14 for a predetermined period at a rising speed higher than the falling speed of the lance 2o. 14 and the end of the lance 205'c is maintained constant.
It is equipped with a lance control device 70 that controls each of the left-right tilting device 40 and the front-back tilting device 50, and a wear amount detector 100 that detects mechanical wear caused by the jetting of the desiliconizing agent at the tip of the lance 20. In order to use the tip of the lance 20 as a moving electrode, an insulating flange 22 made of silicon mica is provided near the center of the lance 20, and the lance 2o is electrically separated vertically by this insulating flange 22. There is. Therefore, the distal end 20A of the lance 20 is
is electrically disconnected from the earth. Also, with this insulating flange 22, the lance 20 can be mechanically separated into the leading end 20A and the rear end 20B, so that when the leading end of the lance 20 is worn out, the parts below the insulating flange 22 can be removed. We are making it possible to do so. The lance 2o also has a flexible hose 24 connected at one end to the lance control device 70, and a heat-resistant insulation MltA26 along the rear end 20B of the lance 20. The other end of the insulated wire 26 is connected to a lance 20 insulated by an insulating flange 22.
It is connected to the tip portion 20A1 of the electrode, that is, the portion used as an electrode. Note that since a conductive desiliconizing agent passes through the inside of the hollow lance 20, the tip portion 2OA used as an electrode is connected to the rear end portion 20B of the lance 20 or the hot metal 14 through the desiliconizing agent.
However, since the volume ratio of the desiliconizing agent to the compressed air is only 0.00714%, the insulation of the tip 20A of the lance 20 is not impaired, and this tip 2OA can be effectively used as an electrode. The vertical drive device 30 includes a pole number changing motor 32, a pinion 34 provided on the drive shaft of the pole number changing motor 32, and a rear end portion 20 of the lance 20 that meshes with the pinion 34.
It consists of a recess 36 formed on the side surface of B. The left-right tilting device 40 is constituted by a hydraulic cylinder 42 that presses the side surface of the lance 20 with the fulcrum 20C of the lance 20 as the center of swing. Further, the longitudinal tilting device 50 has a fulcrum 20D of the lance 20.
It is composed of a hydraulic cylinder 52 that presses the side surface of the lance 20 with the oscillation center being the hydraulic cylinder 52. As shown in FIG. 1, the lance control device 70 includes a pulse generator 72 connected to the drive shaft of the motor 32 of the vertical drive device 30, and counts the number of pulses from the pulse generator 72 to control the tip of the lance 20. A lance position detection circuit 74 that detects the position and the tip 2 of the lance 20
A weak current or change in capacitance is detected in the closed loop A formed by the OA, the hot metal 14 in the tilting gutter 12, and the ground 18, and this is amplified to determine the contact between the hot metal surface 15 and the tip of the lance 20. a logic circuit 78 that controls the position of the lance 20 according to signals from the lance position detection circuit 74 and the hot metal detection circuit 76 and internally stored control logic; It is composed of a drive device 30, a left-right tilting device 40, and a drive circuit 80 that drives the front-back tilting device 50. or,
The lance control device 70 includes the lance position detection circuit 74.
and the detection signal from the hot metal detection circuit 76, the lance 2
Display device 8 that displays the tip position of 0 and the level of the hot metal surface
2 are provided. As shown in FIG. 2, the hot metal detection circuit 76 detects a weak N* in a closed loop A including the insulated wire 26, the tip 2OA of the lance 20, the hot metal 14, the pouring gutter 12, and the ground 18, and thereby In the method of detecting contact between the hot metal 14 and the tip 2OA of the lance 20, and in the closed loop A, a change in capacitance is detected, whereby the hot metal 14
Two types of detection circuits 84 and 86 are built-in to detect the contact between the front end 2OA of the lance 20 and the tip 2OA of the lance 20.
The output signal of 86 is connected to contacts 85 and 87 and a timer (hereinafter referred to as DT).
)1 and DT2, a signal correct/incorrect judgment circuit 88
The hot metal level is detected by contacting the hot metal surface 15 as the lance 20 moves. The output that has passed through the signal correctness determination circuit 88 is output to the logic circuit 78 and the display device 82. The signal correct/incorrect judgment circuit 88 converts the output of the DT1 into an AN
The input terminal of D gate (hereinafter referred to as AND) 1 and the AN
The output of DT2 is connected to the input terminal having an inverting function (hereinafter referred to as an inverter terminal) of D2, and the output of DT2 is connected to the AND
The other inverter terminal of 1 and the input terminal of AND2 are connected, and the outputs of ANDl and AND2 are connected to an OR gate (hereinafter referred to as
The output of OR1 is connected to the inverter terminal of AND3 via DT3, and the outputs of DT1 and DT2 are connected to the input terminal of 0R2 (7). The output terminal is connected to the input terminal of the AND3, and the output of the AND3 is obtained as an output for determining whether the molten metal detection signal is correct or incorrect. That is, the two hot metal contact detection signals from the low current detection circuit 84 and the capacitance detection circuit 86 should always be the same state signal, although there is a slight time difference, and mutually opposite signals are long. If it continues (this time can be set by the DT 3), it is determined that one of them is malfunctioning, and the output is not output to the logic circuit 78 and the display device 82. The wear amount detector 100 is for detecting mechanical wear due to the jetting of the desiliconizing agent at the tip of the lance 20, and as shown in FIG. The detection plate 104 is held approximately horizontally by a coil spring 1o6 so as to be able to swing downward.
A lance 20 is provided in the middle of the downward movement trajectory for adding the desiliconizing agent. Note that the detection plate 104 is connected to the ground 1
8 to a hot metal detection circuit 76 of a lance control device 70. The operation of this embodiment will be explained below. The lowering of the lance 20 for adding the desiliconizing agent is performed by the vertical drive device 3o, and the drive motor 3 of the vertical drive device 30
Since the lance 20 is composed of a pole number changing motor, the lance 20 descends slowly at a low speed as if searching for the molten metal surface 15. Further, when the lance 20 is lowered, the pulse generator 72 and the lance position detection circuit 74 detect the position of the lance 20 on the next @20 days, and the detection result is displayed on the display device 82. The tip of the lance 20, ie l! Tip 20 adopted as a pole
When E contacts the hot metal surface 15, a closed loop A is formed by current and capacitance, as shown by the broken line in FIG. 1, and the hot metal detection circuit 76 detects the hot metal surface 15. Based on this molten metal surface detection signal, the lance 20 is instantaneously stopped by processing by the logic circuit 78 and the drive circuit 80. The position of the tip of the lance 20 at this time means the level of the molten metal surface 15, and the lance position detection circuit 74 indicates the level of the molten metal surface 15.
The level of the hot metal surface at the time of denting is displayed in memory. In the hot metal detection circuit 76, as shown in FIG. 2, hot metal detection is performed by a low current detection circuit 84, a capacitance detection circuit 86, a DTl, 0-2, and a signal correctness determination circuit 88. That is,
In the low current detection circuit 84, a closed loop A is formed including the insulated wire 26, the tip 20A of the lance 20, and the hot metal 14.
A weak current is detected in the lance 20 and amplified to determine contact between the molten metal surface and the lance 20. Similarly, in the capacitance detection circuit 86, in the closed loop A, detection is performed based on a change in capacitance depending on whether or not the lance 20 contacts the hot metal 14. The signals detected by the two detection circuits in this way are transmitted through contacts 85 and 87 to DTl.
, is output to DT2. DTl and DT2 perform processing to cut signals that are shorter than a set time, and this is processed by the signal correct/incorrect judgment circuit 8 that follows.
Send to 8. The signal correctness determination circuit 88 sequentially checks the two detection signals from the low current detection circuit 84 and the capacitance detection circuit 86 to determine whether they are correct or incorrect. In other words, although there is a slight time difference between the signals from the two detection circuits 84 and 86, they should always be the same state signal, and if mutually opposite signals continue for a long time, it is determined that one of them is malfunctioning. Therefore, measures are taken not to output the signal to the logic circuit 78 and display device 82. As described above, the lance 20, which has been temporarily stopped after detecting the level of the surface of the hot metal 14, is raised from its stopping position by a certain set height at high speed by the pole number changing motor 32 of the vertical drive device 3o. , the tip of the lance 20 is maintained at a certain set height relative to the hot metal surface 15. Next, when the hot metal surface 15 rises and comes into contact with the tip of the lance 20 again, the lance 20 is raised by a set height at a high speed and escapes from the hot metal surface in the same manner as described above. The above-mentioned lance raising operation is performed by the lance movement distance measurement by the lance position detection circuit 74 and the arithmetic processing by the logic circuit 78. Further, the logic circuit 78 periodically lowers the lance 20 at a low speed, detects the molten metal surface level, and monitors the rising operation and prevention of collision with the tilting trough 12 and the lance 20. Next, detection of the amount of wear on the lance 20 will be explained. The lance 20 is in the standby position, that is, the lance 20 must be moved from its upper limit during the process of descending to add the desiliconizing agent.
is controlled by a logic circuit 78 to tilt the wear amount detector 100. By kicking this wear amount detector 100, the same judgment as that of detecting the hot metal surface 15 is made by the hot metal detection circuit 76.
done by. Here, the tip 2OA of the lance 20
When the amount of wear increases, that is, when the tip portion 2OA becomes shorter, the timing of kicking the wear amount detector 100, which is always fixed at a fixed position, becomes delayed. In other words, the lance position detection circuit 74 determines that the position of the lance 20 when kicking the wear amount detector 100 is lowered. This difference is the amount of wear, and the amount of wear is calculated by the lance position detection circuit 74 based on the detection timing of the hot metal detection circuit 76, and this result is corrected to calculate the tip position of the lance 20. . Although the tilting operation of the lance 20 has been omitted in the above description, the lance position detection circuit 74 also performs calculations to detect the amount of tilting. In this embodiment, the drive motor 3 of the vertical drive device 30
2 is used as a pole number conversion motor, and by using the low speed side when lowering the lance 20 and the high speed side when raising it, it is possible to improve the accuracy of stopping on the hot metal surface at low speed when lowering. It is possible to prevent the metal from being immersed in the hot metal 14 with a simple structure. Further, when rising, the lance 20 can quickly move away from the molten metal surface at a high speed, and the tip of the lance 20 can be prevented from melting and damage with a simple structure. In the above embodiment, the detection circuit for detecting the contact between the hot metal 14 and the tip of the lance 20 in the hot metal detection circuit 76 is composed of the low current detection circuit 84 and the capacitance detection circuit 86.
Although the present invention is not limited to this, the present invention is not limited to this, and the present invention is not limited to this.
As the detection circuit for detecting contact between the lance 20 and the lance 20, either the low current detection circuit 84 or the capacitance detection circuit 86 may be used. [Effects of the Invention] As explained above, according to the present invention, in the desiliconization reaction, which is accompanied by a large amount of very intense smoke and dust and cannot be visually monitored, it is also possible to avoid high temperatures, suction air from a dust collector, splash, etc. Under adverse conditions, it is possible to accurately detect the lance tip position and the level of the hot metal surface, which have high unstable fluctuation factors, and to grasp the mutual positional relationship with high precision. This has excellent effects such as being able to prevent collisions with other vehicles.

[Brief explanation of drawings]

FIG. 1 is a front view including a partial block diagram, showing an embodiment of position control i0B of a desiliconization agent addition lance in which the m addition lance position control method according to the present invention is adopted, and FIG. ,
FIG. 3 is a block diagram showing the hot metal detection circuit in the same embodiment, and is a perspective view including a partial block diagram showing the main parts of the desiliconization equipment for a blast furnace casthouse to which the present invention is applied. 10... Hot metal gutter, 12... Tilt gutter, 14... Hot metal, 20... Lance, 30... Vertical drive device, 40... Right and left tilting device, 5o... Back and forth tilting device, 60... Lance truck, 70... Lance control lll device.

Claims (4)

[Claims] (1) In a method for controlling the position of an additive lance that sprays and adds additives to molten metal that has flowed down a tap trough and fallen into a tilting trough, the tip and rear ends are electrically insulated and connected. A lance having an integral structure is movable up and down above the molten metal, and the lance is moved down to electrically detect contact between the molten metal and the tip of the lance, and electrically detect contact between the molten metal and the tip of the lance. After detection, the lance tip is separated from the molten metal for a predetermined period at a rising speed higher than the lance's descending speed to maintain a constant distance between the molten metal surface and the lance tip. Method. (2) The addition according to claim 1, wherein the electrical detection of the contact between the molten metal and the lance tip is performed by detecting the presence or absence of a weak current in a closed loop including the molten metal and the lance tip. Lance position control method. (3) electrically detecting contact between the molten metal and the lance tip in a closed loop including the molten metal and the lance tip;
2. The method of controlling the position of an addition lance according to claim 1, wherein the method is performed by detecting a change in capacitance depending on whether or not the tip of the lance comes into contact with molten metal. (4) Electrical detection of contact between the molten metal and the lance tip is performed based on the presence or absence of a weak current in a closed loop including the molten metal and the lance tip, and the electrostatic charge depending on whether or not the lance tip contacts the molten metal in the closed loop. The addition according to claim 1, which is carried out by detecting a change in capacitance and, when the two detection signals substantially match, is adopted as a detection signal of contact between the molten metal and the tip of the lance. Lance position control method.