Boring head for blast furnace and protection method thereof

Abstract

The present application belongs to the technical field of metallurgical blast furnace ironmaking, and provides a drill bit for blast furnace hole opening and a protection method thereof. The drill bit comprises: a main drill body embedded in a secondary drill body, the end face of the secondary drill body away from the secondary drill body being inlaid with a plurality of first drill teeth; and a secondary drill body inlaid with a plurality of second drill teeth distributed on the periphery of the main drill body and on the same side as the first drill teeth; wherein the main drill body is internally installed with a first temperature measuring element, the secondary drill body is internally installed with a second temperature measuring element, and the first temperature measuring element and the second temperature measuring element are respectively electrically connected with a control panel of a blast furnace front robot. The first drill teeth and the second drill teeth arranged in a staggered manner greatly improve the drilling capacity of the drill bit, and can improve the drilling efficiency. The working temperature of the main drill body and the secondary drill body is monitored in real time by the first temperature measuring element and the second temperature measuring element, so that the drill bit can be processed in time by workers, which is conducive to prolonging the service life of the drill bit and reducing the operation cost.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology in metallurgy, specifically to a drill bit for opening blast furnace holes and a method for protecting it. Background Technology

[0002] The furnace-front robot is mainly used for the automatic opening and plugging of the blast furnace taphole. The blast furnace taphole is formed by a liner filled with taphole clay. During opening, a drill bit is installed at the far end of the drill rod to drill through the taphole clay filled in the liner when plugging.

[0003] However, most existing blast furnace drilling bits have the following problems: 1. During the drilling process, the working temperature of the drill bit cannot be monitored in real time. This not only prevents workers from taking timely action on the drill bit (such as reducing speed or cooling), which reduces the service life of the drill bit, but also leads to a delay in judging the timing of drill bit removal. This causes the drill bit to come into direct contact with the high-temperature medium in the furnace when the tap hole is opened, resulting in damage or premature scrapping, which increases operating costs. 2. The drill bit has a one-piece molded structure design, which has poor cooling effect. The drill bit cannot be cooled sufficiently, and its thermal strength cannot be guaranteed. It is prone to overheating and softening during the drilling process, losing its drilling performance. It is necessary to replace the drill bit multiple times to complete the drilling operation of a single iron outlet, resulting in high drill bit consumption and low drilling efficiency.

[0004] Therefore, how to monitor the working temperature of the drill bit in real time and improve the structural design of the drill bit to protect it has become a major problem that industry professionals urgently need to solve. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a drill bit for blast furnace drilling and its protection method, thereby solving the problems of short service life due to the inability to monitor the working temperature of existing drill bits in real time and poor cooling effect due to unreasonable structural design.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A drill bit for drilling holes in a blast furnace, comprising: The main drill body is fitted into the auxiliary drill body, and a plurality of first drill teeth are embedded on its end face away from the auxiliary drill body; and The auxiliary drill body is inlaid with several second drill teeth distributed around the main drill body and on the same side as the first drill teeth; The main drill body has a first temperature measuring element installed inside, and the auxiliary drill body has a second temperature measuring element installed inside. The first and second temperature measuring elements are electrically connected to the control panel of the furnace robot.

[0007] Optionally, the main drill body has a first frustum portion and a second frustum portion with their large ends abutting each other and their small ends moving away from each other, and the first drill tooth is embedded in the small end of the first frustum portion; The first temperature sensing element is inserted into the second frustum from the middle of the small end of the second frustum and extends into the first frustum, for real-time monitoring of the working temperature of the main drill body. The auxiliary drill body has a third frustum, a fourth frustum, and a straight cylinder arranged in sequence. The large ends of the third frustum and the fourth frustum abut against each other, while their small ends are far apart. The second drill tooth is embedded in the side of the third frustum. The second temperature sensing element is inserted obliquely into the fourth frustum section from the straight cylinder section to monitor the working temperature of the auxiliary drill body in real time. The auxiliary drill body has a frustum hole, which extends axially from the middle of the small end of the third frustum to the fourth frustum, and the second frustum is fitted into the frustum hole. The end of the straight section away from the fourth truncated cone section is machined with an external thread to connect with the chisel of the furnace robot.

[0008] Optionally, a first insertion hole extending into the first frustum is provided at the middle of the small end of the second frustum, and a pair of slots are provided at the entrance of the first insertion hole along its radial direction. The first temperature sensing element includes a first temperature sensing rod and a first signal cable connected to each other. A pair of strong magnetic blocks are provided at one end of the first temperature sensing rod near the first signal cable. Each of the strong magnetic blocks is magnetically embedded into each of the slots after the first temperature sensing rod is inserted into the first socket. The fourth frustum portion is provided with an inclined second insertion hole, the entrance of which is a first countersunk hole facing the inside of the straight cylindrical portion; The second temperature sensing element includes a second temperature sensing rod and a second signal cable connected to each other. The end of the second temperature sensing rod near the second signal cable is a strong magnetic cylinder. After the second temperature sensing rod is inserted into the second socket, the strong magnetic cylinder is embedded into the first countersunk hole by magnetic force. The fourth truncated cone section has a wire hole to connect the truncated cone hole and the straight cylinder section. The first signal cable passes through the wire hole and extends into the straight cylinder section. Together with the second signal cable, it passes through the hollow rod and is electrically connected to the control panel of the furnace robot.

[0009] Optionally, both the first temperature sensing element and the second temperature sensing element are armored thermocouple sensors; The second temperature sensing element is arranged in a pair at 180° intervals, and the second socket corresponds to it one by one.

[0010] Optionally, the second frustum portion has a pair of threaded holes symmetrically arranged at 180° intervals on its side, and the fourth frustum portion has a pair of second countersunk holes symmetrically arranged at 180° intervals on its side, the second countersunk holes communicating with the frustum holes and corresponding to the threaded holes; A screw is installed in the second countersunk hole, and the screw is screwed into the threaded hole to detachably fit the second frustum into the frustum hole.

[0011] Optionally, the side of the second frustum is provided with a pair of key bars symmetrically arranged at a 180° interval, the key bars being offset from the threaded hole by 90°; A pair of keyways symmetrically arranged at 180° intervals are provided on the side of the frustum hole, and the keyways are offset from the second countersunk hole by 90°. When the second frustum portion is embedded in the frustum hole, the key bar is engaged with the keyway.

[0012] Optionally, the large end diameter of the first frustum is greater than the large end diameter of the second frustum and smaller than the small end diameter of the third frustum, and the large end diameters of the third frustum and the fourth frustum are equal. The third truncated cone portion has multiple circumferentially distributed first slag discharge channels extending along its generatrix on its side, and the fourth truncated cone portion has multiple circumferentially distributed second and third slag discharge channels extending along its generatrix on its side. The second slag discharge trough corresponds one-to-one with the first slag discharge trough and is interconnected to form a main slag discharge channel. The third slag discharge trough is staggered from the second slag discharge trough to form a secondary slag discharge channel.

[0013] Optionally, the second slag discharge trough is connected to the interior of the straight cylinder through the air jet hole built into the fourth frustum portion, for spraying positive pressure nitrogen gas to cool the drill bit; The nitrogen gas comes from an external gas supply source, and the gas pump of the gas supply source is connected to the inside of the straight cylinder through a hollow rod.

[0014] Optionally, both the first drill tooth and the second drill tooth are hemispherical, wherein the radius of the first drill tooth is larger than the radius of the second drill tooth; The first drilling tooth is embedded in the small end of the first frustum by insert welding, and the second drilling tooth is embedded in the side of the third frustum by insert welding.

[0015] A method for protecting drill bits used for blast furnace drilling, comprising the following steps: S1. Select the first and second temperature measuring elements with the maximum range greater than the blast furnace ironmaking temperature, and embed them in the main drill body and the auxiliary drill body respectively. After the first and second temperature measuring elements are electrically connected to the control panel of the furnace robot, install the drill bit on the chisel of the furnace robot. S2. Start the furnace robot through the control panel to drive the drill bit to drill into the blast furnace taphole. At the same time, start the gas pump of the gas supply source to pump nitrogen into the straight section so that it is sprayed out from the jet hole. The current furnace temperature, furnace wall thickness, drill bit speed, drilling depth and nitrogen flow rate are displayed on the control panel. S3. The working temperatures of the main drill body and the auxiliary drill body are collected in real time using the first and second temperature measuring elements respectively. Then, the temperature rise curves of the main drill body and the auxiliary drill body are plotted with time as the horizontal axis and temperature as the vertical axis and displayed on the control panel. Among them, time is the working time of the drill bit, and the temperature of the auxiliary drill body temperature rise curve is the average value of the working temperature of the auxiliary drill body collected by a pair of second temperature measuring elements. S4. Based on the temperature rise curves of the main drill body and the auxiliary drill body, the temperature derivative of the main drill body and the auxiliary drill body with respect to time is calculated by the built-in program of the control panel to analyze the temperature rise rate and identify the temperature change point. S5. Compare the temperature rise curves of the main drill body and the auxiliary drill body through the built-in program on the control panel, and make the following adjustments to the working status of the drill bit for protection purposes: When the drill bit's depth of cut is less than 2 / 3 of the furnace wall thickness: If the smaller value of the temperature rise curves of the main drill body and the auxiliary drill body at the current time is less than the first preset temperature, the drill bit will continue drilling at the current rotation speed. If the smaller of the temperature values ​​corresponding to the current time in the temperature rise curves of the main drill body and the auxiliary drill body is greater than or equal to the first preset temperature and less than the second preset temperature, the drill bit will reduce its speed by one level and then continue drilling. If the temperature rise curves of the main drill body and the auxiliary drill body at the current time are smaller than or equal to the second preset temperature and less than the third preset temperature, the drill bit will reduce its speed by one level and continue drilling. The operating frequency of the air pump will be adjusted by the built-in program on the control panel to double the current nitrogen flow rate. When the drill bit's depth of cut is greater than or equal to 2 / 3 of the furnace wall thickness but less than the furnace wall thickness: If the smaller value of the temperature rise curves of the main drill body and the auxiliary drill body corresponding to the current time is greater than or equal to the second preset temperature and less than the third preset temperature, and the time difference between the temperature change point of the main drill body and the temperature change point of the auxiliary drill body is greater than or equal to the preset time, the drill bit will continue to drill at the current rotation speed. If the smaller of the temperatures corresponding to the current time in the temperature rise curves of the main drill body and the auxiliary drill body is greater than or equal to the third preset temperature, or if the time difference between the temperature change points of the main drill body and the auxiliary drill body is less than the preset time, the drill bit reverses and retracts to remove the drill rod from the blast furnace taphole. When the drill bit's depth of cut equals the furnace wall thickness: the drill bit reverses and retracts to remove the drill rod from the blast furnace taphole.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The staggered arrangement of the first and second drilling teeth greatly enhances the drilling capability of this drill bit and improves drilling efficiency. The real-time monitoring of the working temperature of the main drill body and auxiliary drill body by the first and second temperature measuring elements allows the operator to handle the drill bit in a timely manner, which helps to extend the service life of the drill bit and reduce operating costs.

[0017] 2. The main slag discharge channel formed by the first and second slag discharge channels and the secondary slag discharge channel formed by the third slag discharge channel greatly enhances the slag discharge capacity of this drill bit, thereby further improving drilling efficiency.

[0018] 3. Nitrogen gas is sprayed through the jet hole to fully cool the main drill body and auxiliary drill body, ensuring the thermal strength of the drill bit and preventing softening. This ensures the drilling performance of the first and second drilling teeth, avoids frequent drill bit replacements, reduces drill bit consumption, and thus reduces operating costs.

[0019] 4. The working temperatures of the main drill body and the auxiliary drill body are collected in real time by the first and second temperature measuring elements to obtain their temperature rise curves. Combined with specific working parameters (such as drill bit speed and depth of cut), a multi-stage control and protection strategy is formed. This strategy can adjust the working state of the drill bit in a timely manner, accurately determine the timing of drill bit withdrawal, and prevent the drill bit from being damaged, thereby achieving drill bit protection. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a top view of the structure of the present invention; Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure along the middle AA direction; Figure 4 for Figure 2 A schematic diagram of the structure after a cross-section along the BB direction and a 90° counterclockwise rotation; Figure 5 for Figure 2A schematic diagram of the structure after a cross-section along the CC direction and rotation counterclockwise by 45°. Figure 6 A three-dimensional structural diagram of the main drill body; Figure 7 A three-dimensional structural diagram of the auxiliary drill body; Figure 8 A top view of the auxiliary drill body; Figure 9 A schematic diagram of the auxiliary drill body from below; Figure 10 This is a three-dimensional structural diagram of the first temperature sensing element; Figure 11 This is a three-dimensional structural diagram of the second temperature sensing element. Detailed Implementation

[0022] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.

[0028] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] See Figures 1 to 11 As shown, in one aspect, the present invention provides a drill bit for blast furnace drilling, comprising: A main drill body 100 is fitted into a secondary drill body 200, and a plurality of first drill teeth 110 are embedded on its end face away from the secondary drill body 200; and The auxiliary drill body 200 is inlaid with several second drill teeth 210 distributed around the main drill body 100 and on the same side as the first drill teeth 110; The main drill body 100 is equipped with a first temperature measuring element 120, and the auxiliary drill body 200 is equipped with a second temperature measuring element 220. The first temperature measuring element 120 and the second temperature measuring element 220 are electrically connected to the control panel of the furnace robot (not shown in the figure).

[0030] Specifically, the main drill body 100 has a first frustum and a second frustum with their large ends abutting each other and their small ends moving away from each other. A first drill tooth 110 is embedded in the small end of the first frustum. A first temperature sensing element 120 is inserted into the second frustum from the middle of its small end and extends into the first frustum, used to monitor the working temperature of the main drill body 100 in real time. The auxiliary drill body 200 has a third frustum, a fourth frustum, and a straight cylindrical section arranged sequentially. The large ends of the third and fourth frustums abut each other, and their small ends moving away from each other. The second drilling tooth 210 is embedded in the side of the third truncated cone (the curved surface where its generatrix is ​​located); the second temperature measuring element 220 is inserted obliquely into the fourth truncated cone from the straight cylinder to monitor the working temperature of the auxiliary drill body 200 in real time; the auxiliary drill body 200 is provided with a truncated cone hole 230, which extends axially from the middle of the small end of the third truncated cone to the fourth truncated cone, and the second truncated cone is fitted into the truncated cone hole 230; the end of the straight cylinder away from the fourth truncated cone is machined with an external thread to connect with the chisel of the furnace robot. When the blast furnace needs to be drilled, this drill bit is installed on the chisel of the furnace-front robot. The chisel is then adjusted to align with the blast furnace's preset tapping channel direction and the drill bit is aligned with the tapping reference point. The furnace-front robot is then activated via the control panel to drive the chisel to drill (feed + rotation), which in turn drives the drill bit to drill the tapping mud filling the tapping channel. During drilling, the first drilling tooth 110 contacts the tapping mud before the second drilling tooth 210, playing a primary role. The second drilling tooth 210, positioned later, expands the drilling range and plays an auxiliary role. The two work together to complete the drilling and obtain a perfect tapping channel. Simultaneously, the first temperature sensing element 120 and the second temperature sensing element 220 transmit the real-time operating temperatures of the main drill body 100 and the auxiliary drill body 200 to the furnace-front robot, thereby adjusting the drill bit's operating status (e.g., reducing the drill bit's rotation speed when the operating temperature is ≥600℃, rapidly retracting when the temperature is ≥1500℃, and timely retraction of the chisel), achieving a protective purpose. In other words, the staggered arrangement of the first drilling teeth 110 and the second drilling teeth 210 greatly enhances the drilling capability of this drill bit and improves drilling efficiency. The real-time monitoring of the working temperature of the main drill body 100 and the auxiliary drill body 200 by the first temperature measuring element 120 and the second temperature measuring element 220 enables the operator to handle the drill bit in a timely manner, which helps to extend the service life of the drill bit and reduce operating costs.

[0031] See Figure 6 As shown, a first insertion hole 101 extending into the first truncated cone is provided at the middle of the small end of the second truncated cone portion, and a pair of slots 102 are provided radially at the entrance of the first insertion hole 101; see also Figure 10As shown, the first temperature sensing element 120 includes a first temperature sensing rod 121 and a first signal cable 123 connected to each other. A pair of strong magnetic blocks 122 are provided at one end of the first temperature sensing rod 121 near the first signal cable 123. Each strong magnetic block 122 is magnetically embedded into a slot 102 after the first temperature sensing rod 121 is inserted into the first insertion hole 101. (See also...) Figure 3 and Figure 9 As shown, the fourth frustum portion has an inclined second insertion hole 201, the entrance of which faces the first countersunk hole 202 into the straight cylindrical portion; see also Figure 11 As shown, the second temperature sensing element 220 includes a second temperature sensing rod 221 and a second signal cable 223 connected to each other. The end of the second temperature sensing rod 221 near the second signal cable 223 is a strong magnetic cylinder 222. After the second temperature sensing rod 221 is inserted into the second insertion hole 201, the strong magnetic cylinder 222 is embedded into the first countersunk hole 202 by magnetic force. A wire hole is opened in the fourth frustum to connect the frustum hole 230 and the straight cylinder. The first signal cable 123 passes through the wire hole and extends into the straight cylinder. Together with the second signal cable 223, it passes through the hollow rod and is electrically connected to the control panel of the furnace robot. Before the second frustum portion is fitted into the frustum hole 230, the first temperature sensing rod 121 of the first temperature sensing element 120 is inserted into the first socket 101, and then the first signal cable 123 is passed through the wire hole. Before the straight cylinder portion is connected to the drill rod, the second temperature sensing rod 221 of the second temperature sensing element 220 is inserted into the second socket 201. The second signal cable 223 can be bundled together with the first signal cable 123, so that it passes through the hollow drill rod and is electrically connected to the control panel of the furnace robot. That is to say, the above structure makes the disassembly and assembly of the first temperature sensing element 120 and the second temperature sensing element 220 more convenient, which is beneficial for later maintenance.

[0032] In this embodiment, both the first temperature sensing element 120 and the second temperature sensing element 220 are armored thermocouple sensors, and a pair of second temperature sensing elements 220 are arranged symmetrically at 180° intervals, with the second socket 201 corresponding to each of them.

[0033] See Figure 4 As shown, the second frustum has a pair of threaded holes 103 symmetrically arranged at 180° intervals on its side, and the fourth frustum has a pair of second countersunk holes 203 symmetrically arranged at 180° intervals on its side. The second countersunk holes 203 communicate with the frustum hole 230 and correspond to the threaded holes 103. A screw (not shown in the figure) is installed in the second countersunk hole 203, and the screw is screwed into the threaded hole to detachably fit the second frustum into the frustum hole 230. That is to say, the main drill body 100 and the auxiliary drill body 200 are fitted together by a detachable threaded connection, making maintenance more convenient.

[0034] See Figure 6 and Figure 7As shown, the side of the second frustum is provided with a pair of key bars 104 symmetrically arranged at 180° intervals, and the key bars 104 are offset from the threaded holes 103 by 90°; the side of the frustum hole 230 is provided with a pair of keyways 204 symmetrically arranged at 180° intervals, and the keyways 204 are offset from the second countersunk hole 203 by 90°; when the second frustum is inserted into the frustum hole 230, the key bars 104 and the keyways 204 are engaged. In this way, the connection strength between the main drill body 100 and the auxiliary drill body 200 can be improved, making the drill bit stable and reliable, thereby ensuring the drilling capability of the drill bit.

[0035] See Figure 6 and Figure 7 As shown, the large end diameter of the first truncated cone is larger than the large end diameter of the second truncated cone and smaller than the small end diameter of the third truncated cone. The large end diameters of the third truncated cone and the fourth truncated cone are equal. Multiple circumferentially distributed first slag discharge troughs 205 extending along their generatrices are provided on the side of the third truncated cone. Multiple circumferentially distributed second slag discharge troughs 206 and third slag discharge troughs 207 extending along their generatrices are provided on the side of the fourth truncated cone. The second slag discharge troughs 206 and the first slag discharge troughs 205 correspond one-to-one and are interconnected to form a main slag discharge channel. The third slag discharge troughs 207 and the second slag discharge troughs 206 are staggered to form a secondary slag discharge channel. Thus, the first truncated cone abuts against the small end of the third truncated cone, allowing the cutting mud and debris generated during drilling by the first drill tooth 110 to promptly enter the first cuttings discharge groove 205. Simultaneously, because the large ends of the third and fourth truncated cones have the same diameter, the cutting mud and debris generated during drilling by the second drill tooth 210 can quickly enter the second and third cuttings discharge grooves 206 and 207, accelerating the movement of the cutting mud and debris in the opposite direction of drilling. In other words, the main cuttings discharge channel formed by the first and second cuttings discharge grooves and the secondary cuttings discharge channel formed by the third cuttings discharge groove greatly enhance the cuttings discharge capacity of this drill bit, further improving drilling efficiency.

[0036] See Figure 5As shown, the second slag discharge trough 206 is connected to the interior of the straight cylinder section through the air jet 208 built into the fourth truncated cone section, used to spray positive pressure nitrogen gas (or other inert gas) to cool the drill bit; the nitrogen gas comes from an external air supply source (not shown in the figure), and the air pump of the air supply source is connected to the interior of the straight cylinder section through the hollow drill rod. When drilling begins, the air pump of the air supply source starts, pumping nitrogen gas through the hollow drill rod and the interior of the straight cylinder section before spraying it out from the air jet 208, and then spreading along the second slag discharge trough 206 and the first slag discharge trough 205, while blowing away the cuttings and debris, and purging the main drill body 100 and the auxiliary drill body 200 to achieve cooling and protection of both. In other words, by spraying nitrogen gas through the jet hole 208, the main drill body 100 and the auxiliary drill body 200 can be fully cooled, ensuring the thermal strength of the drill bit and preventing softening. This ensures the drilling performance of the first drill tooth 110 and the second drill tooth 210, avoids multiple drill bit replacements, reduces drill bit consumption, and thus reduces operating costs.

[0037] In this embodiment, there are four slag discharge channels circumferentially distributed from the first to the third. The third slag discharge channel 207 is staggered from the second slag discharge channel 206 by 45°. The four first slag discharge channels 205 divide a number of second drill teeth 210 into four equal groups. The four third slag discharge channels 207 are divided into two pairs, one of which is connected to a pair of second countersunk holes 203.

[0038] See Figure 1 As shown, both the first drilling tooth 110 and the second drilling tooth 210 are hemispherical, with the radius of the first drilling tooth 110 being larger than that of the second drilling tooth 210. The first drilling tooth 110 is embedded in the small end of the first frustum by a plug-in welding method, and the second drilling tooth 210 is embedded in the side of the third frustum by a plug-in welding method. The hemispherical drilling teeth have high wear resistance, while the plug-in welding structure has high strength, making this drill bit stable and reliable, and further ensuring the drilling capability of this drill bit.

[0039] In this embodiment, both the first drilling tooth 110 and the second drilling tooth 210 are preferably made of tungsten-cobalt alloy. This results in high strength and a long service life.

[0040] On the other hand, the present invention provides a method for protecting drill bits used in blast furnace drilling, comprising the following steps: S1. Select the first temperature measuring element 120 and the second temperature measuring element 220 with the maximum range greater than the blast furnace ironmaking temperature, and embed them in the main drill body 100 and the auxiliary drill body 200 respectively. After the first temperature measuring element 120 and the second temperature measuring element 220 are electrically connected to the control panel of the furnace robot, the drill bit is installed on the chisel of the furnace robot.

[0041] Specifically, if the blast furnace ironmaking temperature is 1500℃, then the maximum range of the selected first temperature measuring element 120 and the second temperature measuring element 220 can be 1600℃.

[0042] S2. Start the furnace robot via the control panel to drive the drill bit to drill into the blast furnace taphole. At the same time, start the gas pump of the gas supply source to pump nitrogen into the straight section so that it is sprayed out from the jet hole 208. The control panel displays the current blast furnace temperature, furnace wall thickness, drill bit speed, drilling depth and nitrogen flow rate.

[0043] Specifically, the furnace temperature is collected from the temperature sensor on the blast furnace itself, the furnace wall thickness is taken from the furnace wall thickness near the taphole, the drill bit rotation speed is the real-time rotation speed, the depth of cut is the feed rate, and nitrogen gas is sprayed out from the jet hole 208 to cool the main drill body 100 and the auxiliary drill body 200 in real time.

[0044] S3. The working temperatures of the main drill body 100 and the auxiliary drill body 200 are collected in real time using the first temperature measuring element 120 and the second temperature measuring element 220, respectively. Then, the temperature rise curves of the main drill body 100 and the auxiliary drill body 200 are plotted with time as the horizontal axis and temperature as the vertical axis and displayed on the control panel. Among them, time is the working time of the drill bit, and the temperature of the auxiliary drill body 200 temperature rise curve is the average value of the working temperature of the auxiliary drill body 200 collected by a pair of second temperature measuring elements 220.

[0045] S4. Based on the temperature rise curves of the main drill body 100 and the auxiliary drill body 200, the temperature derivative of the main drill body 100 and the auxiliary drill body 200 with respect to time is calculated by the built-in program of the control panel to analyze the temperature rise rate and identify the temperature change point.

[0046] Specifically, the temperature derivatives with respect to time for the main drill body 100 and the auxiliary drill body 200 are calculated using the first derivative formula dy / dx=dT / dt.

[0047] S5. Compare the temperature rise curves of the main drill body 100 and the auxiliary drill body 200 through the built-in program on the control panel, and make the following adjustments to the working status of the drill bit for protection purposes: When the drill bit's depth of cut is less than 2 / 3 of the furnace wall thickness: If the smaller of the temperature values ​​corresponding to the current time in the temperature rise curves of the main drill body 100 and the auxiliary drill body 200 is less than the first preset temperature, the drill bit will continue drilling at the current rotation speed. If the temperature rise curves of the main drill body 100 and the auxiliary drill body 200 at the current time are smaller than or equal to the first preset temperature and less than the second preset temperature, the drill bit will reduce its speed by one level and then continue drilling. If the temperature rise curves of the main drill body 100 and the auxiliary drill body 200 correspond to the smaller value of the temperature at the current time that is greater than or equal to the second preset temperature and less than the third preset temperature, the drill bit will reduce its speed by one level and continue drilling. The operating frequency of the air pump will be adjusted by the built-in program on the control panel to double the current nitrogen flow rate. When the drill bit's depth of cut is greater than or equal to 2 / 3 of the furnace wall thickness but less than the furnace wall thickness: If the smaller of the temperatures corresponding to the current time of the temperature rise curves of the main drill body 100 and the auxiliary drill body 200 is greater than or equal to the second preset temperature and less than the third preset temperature, and the time difference between the temperature change point of the main drill body 100 and the temperature change point of the auxiliary drill body 200 is greater than or equal to the preset time, the drill bit will continue to drill at the current rotation speed. If the smaller of the temperatures corresponding to the current time of the temperature rise curves of the main drill body 100 and the auxiliary drill body 200 is greater than or equal to the third preset temperature, or if the time difference between the temperature change point of the main drill body 100 and the temperature change point of the auxiliary drill body 200 is less than the preset time, the drill bit reverses and retracts to remove the drill rod from the blast furnace taphole. When the drill bit's depth of cut equals the furnace wall thickness: the drill bit reverses and retracts to remove the drill rod from the blast furnace taphole.

[0048] Specifically, the first preset temperature is 600℃, the second preset temperature is 1000℃, and the third preset temperature is 1500℃ (i.e., the ironmaking temperature and furnace temperature of the blast furnace); the rotation speed of the drill bit after the speed reduction is 0.8 times that before the speed reduction, for example, the rotation speed of the drill bit before the speed reduction is 100r / min, and the rotation speed after the speed reduction is 80r / min; the preset time is 120s (seconds).

[0049] In summary, this invention uses the first temperature sensing element 120 and the second temperature sensing element 220 to collect the working temperatures of the main drill body 100 and the auxiliary drill body 200 in real time to obtain their temperature rise curves. Combined with specific working condition parameters (such as drill bit speed and depth of cut), a multi-stage control and protection strategy is formed, which can adjust the working state of the drill bit in a timely manner, accurately determine the timing of drill bit withdrawal, and prevent the drill bit from being damaged, thereby achieving drill bit protection.

[0050] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the technical solutions of the present invention. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of the patent of the present invention.

Claims

1. A drill bit for opening holes in a blast furnace, characterized in that, include: The main drill body is fitted into the auxiliary drill body, and a number of first drill teeth are embedded on its end face away from the auxiliary drill body; and The auxiliary drill body is inlaid with several second drill teeth distributed around the main drill body and on the same side as the first drill teeth; The main drill body is equipped with a first temperature measuring element, and the auxiliary drill body is equipped with a second temperature measuring element. The first and second temperature measuring elements are electrically connected to the control panel of the furnace robot. The main drill body has a first frustum and a second frustum with their large ends abutting each other and their small ends moving away from each other, and the first drill tooth is embedded in the small end of the first frustum. The first temperature sensing element is inserted into the second frustum from the middle of the small end of the second frustum and extends into the first frustum, for real-time monitoring of the working temperature of the main drill body. The auxiliary drill body has a third frustum, a fourth frustum, and a straight cylinder arranged in sequence. The large ends of the third frustum and the fourth frustum abut against each other, while their small ends are far apart. The second drill tooth is embedded in the side of the third frustum. The second temperature sensing element is inserted obliquely into the fourth frustum section from the straight cylinder section to monitor the working temperature of the auxiliary drill body in real time. The auxiliary drill body has a frustum hole, which extends axially from the middle of the small end of the third frustum to the fourth frustum, and the second frustum is fitted into the frustum hole. The straight section has an external thread at the end away from the fourth truncated cone section to connect with the chisel of the furnace robot. The second frustum portion has a first insertion hole extending into the first frustum portion at its small end, and the entrance of the first insertion hole has a pair of slots along its radial direction. The first temperature sensing element includes a first temperature sensing rod and a first signal cable connected to each other. A pair of strong magnetic blocks are provided at one end of the first temperature sensing rod near the first signal cable. Each of the strong magnetic blocks is magnetically embedded into each of the slots after the first temperature sensing rod is inserted into the first socket. The fourth frustum portion is provided with an inclined second insertion hole, the entrance of which is a first countersunk hole facing the inside of the straight cylindrical portion; The second temperature sensing element includes a second temperature sensing rod and a second signal cable connected to each other. The end of the second temperature sensing rod near the second signal cable is a strong magnetic cylinder. After the second temperature sensing rod is inserted into the second socket, the strong magnetic cylinder is embedded into the first countersunk hole by magnetic force. The fourth truncated cone section has a wire hole to connect the truncated cone hole and the straight cylinder section. The first signal cable passes through the wire hole and extends into the straight cylinder section. Together with the second signal cable, it passes through the hollow rod and is electrically connected to the control panel of the furnace robot. The large end diameter of the first frustum is greater than the large end diameter of the second frustum and smaller than the small end diameter of the third frustum; the large end diameters of the third frustum and the fourth frustum are equal. The third truncated cone portion has multiple circumferentially distributed first slag discharge channels extending along its generatrix on its side, and the fourth truncated cone portion has multiple circumferentially distributed second and third slag discharge channels extending along its generatrix on its side. The second slag discharge trough corresponds one-to-one with the first slag discharge trough and is interconnected to form a main slag discharge channel. The third slag discharge trough is staggered from the second slag discharge trough to form a secondary slag discharge channel. The second slag discharge trough is connected to the inside of the straight cylinder through the air jet hole built into the fourth truncated cone section, and is used to spray positive pressure nitrogen gas to cool the drill bit; The nitrogen gas comes from an external gas supply source, and the gas pump of the gas supply source is connected to the inside of the straight cylinder through a hollow rod.

2. The drill bit for blast furnace drilling according to claim 1, characterized in that: Both the first and second temperature sensing elements are armored thermocouple sensors; The second temperature sensing element is arranged in a pair at 180° intervals, and the second socket corresponds to it one by one.

3. The drill bit for blast furnace drilling according to claim 1 or 2, characterized in that: The second frustum has a pair of threaded holes symmetrically arranged at 180° intervals on its side, and the fourth frustum has a pair of second countersunk holes symmetrically arranged at 180° intervals on its side. The second countersunk holes communicate with the frustum holes and correspond to the threaded holes. A screw is installed in the second countersunk hole, and the screw is screwed into the threaded hole to detachably fit the second frustum into the frustum hole.

4. The drill bit for blast furnace drilling according to claim 3, characterized in that: The side of the second frustum is provided with a pair of key bars symmetrically arranged at a 180° interval, and the key bars are offset from the threaded holes by 90°; A pair of keyways symmetrically arranged at 180° intervals are provided on the side of the frustum hole, and the keyways are offset from the second countersunk hole by 90°. When the second frustum portion is embedded in the frustum hole, the key bar is engaged with the keyway.

5. The drill bit for blast furnace drilling according to claim 1, characterized in that: Both the first and second drill teeth are hemispherical, wherein the radius of the first drill tooth is larger than the radius of the second drill tooth; The first drilling tooth is embedded in the small end of the first frustum by insert welding, and the second drilling tooth is embedded in the side of the third frustum by insert welding.

6. A method for protecting a drill bit used for blast furnace drilling, for protecting the drill bit used for blast furnace drilling as described in any one of claims 1 to 5, characterized in that, The protection method includes the following steps: S1. Select the first and second temperature measuring elements with the maximum range greater than the blast furnace ironmaking temperature, and embed them in the main drill body and the auxiliary drill body respectively. After the first and second temperature measuring elements are electrically connected to the control panel of the furnace robot, install the drill bit on the chisel of the furnace robot. S2. Start the furnace robot through the control panel to drive the drill bit to drill into the blast furnace taphole. At the same time, start the gas pump of the gas supply source to pump nitrogen into the straight section so that it is sprayed out from the jet hole. The current furnace temperature, furnace wall thickness, drill bit speed, drilling depth and nitrogen flow rate are displayed on the control panel. S3. The working temperatures of the main drill body and the auxiliary drill body are collected in real time using the first and second temperature measuring elements respectively. Then, the temperature rise curves of the main drill body and the auxiliary drill body are plotted with time as the horizontal axis and temperature as the vertical axis and displayed on the control panel. Among them, time is the working time of the drill bit, and the temperature of the auxiliary drill body temperature rise curve is the average value of the working temperature of the auxiliary drill body collected by a pair of second temperature measuring elements. S4. Based on the temperature rise curves of the main drill body and the auxiliary drill body, the temperature derivative of the main drill body and the auxiliary drill body with respect to time is calculated by the built-in program of the control panel to analyze the temperature rise rate and identify the temperature change point. S5. Compare the temperature rise curves of the main drill body and the auxiliary drill body through the built-in program on the control panel, and make the following adjustments to the working status of the drill bit for protection purposes: When the drill bit's depth of cut is less than 2 / 3 of the furnace wall thickness: If the smaller value of the temperature rise curves of the main drill body and the auxiliary drill body at the current time is less than the first preset temperature, the drill bit will continue drilling at the current rotation speed. If the smaller of the temperature values ​​corresponding to the current time in the temperature rise curves of the main drill body and the auxiliary drill body is greater than or equal to the first preset temperature and less than the second preset temperature, the drill bit will reduce its speed by one level and then continue drilling. If the temperature rise curves of the main drill body and the auxiliary drill body at the current time are smaller than or equal to the second preset temperature and less than the third preset temperature, the drill bit will reduce its speed by one level and continue drilling. The operating frequency of the air pump will be adjusted by the built-in program on the control panel to double the current nitrogen flow rate. When the drill bit's depth of cut is greater than or equal to 2 / 3 of the furnace wall thickness but less than the furnace wall thickness: If the smaller value of the temperature rise curves of the main drill body and the auxiliary drill body corresponding to the current time is greater than or equal to the second preset temperature and less than the third preset temperature, and the time difference between the temperature change point of the main drill body and the temperature change point of the auxiliary drill body is greater than or equal to the preset time, the drill bit will continue to drill at the current rotation speed. If the smaller of the temperatures corresponding to the current time in the temperature rise curves of the main drill body and the auxiliary drill body is greater than or equal to the third preset temperature, or if the time difference between the temperature change points of the main drill body and the auxiliary drill body is less than the preset time, the drill bit reverses and retracts to remove the drill rod from the blast furnace taphole. When the drill bit's depth of cut equals the furnace wall thickness: the drill bit reverses and retracts to remove the drill rod from the blast furnace taphole.

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