Rotary Joint for Converter Powder Injection and Treatment Method for Abrasion of Powder Delivery Pipe

Abstract

The present invention discloses a rotary joint for converter powder injection and a method for dealing with abrasion of a powder delivery pipe, including a single-channel rotary joint, a multi-channel rotary joint, a third powder delivery pipe, a fourth powder delivery pipe, and a converter trunnion; the multi-channel rotary joint includes a housing, a core shaft, a second powder delivery pipe, and a second powder delivery pipe alarm pipe; the housing is sleeved outside the core shaft and is rotationally connected to the core shaft; the second powder delivery pipe is located inside the core shaft; the second powder delivery pipe includes an inner pipe, an outer pipe, and a filter cloth coated on the outer wall of the inner pipe, the filter cloth is adhered to the outer wall of the inner pipe through an adhesive, the outer pipe is sleeved outside the inner pipe and there is a gap between the outer pipe and the inner pipe; the second powder delivery pipe alarm pipe is communicated with the gap. After the inner pipe of the powder delivery pipe is abraded, the powder is blocked inside the inner pipe by the filter cloth; the air supply valve supplies air into the gap through the alarm pipe; the treatment of the abrasion of the inner pipe is completed. The present invention uses the filter cloth to block the powder to avoid leakage and abrasion of other components, and gives a breakage warning through the alarm pipe.

Description

Technical Field

[0001] The present invention belongs to the technical field of converter steelmaking, and particularly relates to a rotary joint for converter powder injection and a method for treating a worn powder delivery pipe with the rotary joint. Background Art

[0002] Powder injection metallurgy is to make solid materials into powders or fine particles and continuously inject them into the molten bath by using gas as the carrier gas. It changes the traditional way of adding metallurgical materials into the furnace in the form of "lumps" and "batch materials", significantly increases the contact area between the materials and the molten metal, and improves the kinetic conditions of metallurgical reactions. The powder injection metallurgy process is easy to achieve continuous and controllable batching and feeding, can more reasonably control the reactions in the molten bath and the temperature of the molten bath, and avoid sudden changes in the slag composition and the temperature of the molten bath caused by the traditional feeding method.

[0003] Converter steelmaking is currently the most important steelmaking method in the world. Converter powder injection includes various forms such as bottom blowing powder injection, side blowing powder injection, and tapping hole powder injection. Different powder injection methods can achieve different metallurgical effects and have significant advantages compared with the traditional steelmaking method. However, the converter does not remain stationary but rotates 360° around the trunnion, which requires the powder delivery pipeline to rotate with the furnace, posing new requirements for the structure of the rotary joint. Moreover, the powder flows at high speed in the powder delivery pipeline, which will cause wear to the pipe wall. If the pipe wall is worn through and not discovered and emergently disposed of in time, on the one hand, it is easy to cause steelmaking accidents, and on the other hand, it is easy to damage other components of the rotary joint. Existing rotary joints do not have the above functions. At the same time, once the powder delivery pipeline is worn through, the rotary joint must be replaced. The structure and connection method of the rotary joint determine the time required for replacement. The structure and connection method of existing rotary joints are complex, time-consuming and laborious to disassemble and install, and delay the production rhythm. Summary of the Invention

[0004] Aiming at the problems existing in the existing rotary joint, the present invention provides a rotary joint for converter powder injection, which can provide an alarm signal and perform an emergency operation instantly when the powder delivery pipeline is worn through, ensure the normal smelting of this heat, and then perform the replacement operation after tapping; moreover, the structure and connection method of the rotary joint of the present invention are simple, easy to disassemble and install, and save the replacement time.

[0005] The present invention adopts the following technical solutions:

[0006] The rotary joint for converter powder injection includes a single-channel rotary joint, a multi-channel rotary joint, a third powder delivery pipe, a fourth powder delivery pipe, and a converter trunnion. The single-channel rotary joint includes a rotary joint and a first powder delivery pipe located inside the rotary joint. The multi-channel rotary joint includes a housing, a core shaft, a second powder delivery pipe, and a second powder delivery pipe alarm pipe. One end of the core shaft is connected to the rotary joint, and the other end is connected to the converter trunnion. The housing is sleeved outside the core shaft and is rotatably connected to the core shaft. The second powder delivery pipe is located inside the core shaft. The second powder delivery pipe includes an inner pipe, an outer pipe, and a filter cloth bonded to the outer wall of the inner pipe. The outer pipe is sleeved outside the inner pipe and there is a gap between the outer pipe and the inner pipe. The second powder delivery pipe alarm pipe is communicated with the gap. The first powder delivery pipe, the second powder delivery pipe, the third powder delivery pipe, and the fourth powder delivery pipe are communicated in sequence.

[0007] The present invention further discloses a rotary joint for converter powder injection with alarm function, which includes a single-channel rotary joint, a multi-channel rotary joint, a third powder delivery pipe, a fourth powder delivery pipe, a converter trunnion, a pressure alarm instrument, and a gas supply valve. The single-channel rotary joint includes a rotary joint and a first powder delivery pipe located inside the rotary joint. The multi-channel rotary joint includes a housing, a core shaft, a second powder delivery pipe, and a second powder delivery pipe alarm pipe. The first powder delivery pipe, the second powder delivery pipe, the third powder delivery pipe, and the fourth powder delivery pipe are communicated in sequence. One end of the core shaft is connected to the rotary joint, and the other end is connected to the converter trunnion. The housing is sleeved outside the core shaft and is rotatably connected to the core shaft. The second powder delivery pipe is located inside the core shaft. The second powder delivery pipe includes an inner pipe, an outer pipe, and a filter cloth bonded to the outer wall of the inner pipe. The outer pipe is sleeved outside the inner pipe and there is a gap between the outer pipe and the inner pipe. One end of the second powder delivery pipe alarm pipe is communicated with the gap, and the other end is connected with a pressure alarm instrument and a gas supply valve. Preferably, the rotary joint for converter powder injection with alarm function includes a pressure regulating valve and a backflush gas source. The gas supply valve, the pressure regulating valve, and the backflush gas source are communicated in sequence. The gas given by the gas source is adjusted by the pressure regulating valve and then blown by the gas supply valve into the second powder delivery pipe alarm pipe and then into the gap, which can not only maintain the carrier gas balance in the inner pipe but also avoid the accumulation of powder at the worn-out place.

[0008] The present invention discloses a method for dealing with the abrasion of the inner pipe of the second powder delivery pipe by using the above-mentioned rotatable joint for alarming converter powder injection. After the inner pipe of the second powder delivery pipe is abraded, the carrier gas leaks to the air pressure alarm instrument, triggering the alarm of the air pressure alarm instrument; the powder is blocked by the filter cloth inside the inner pipe of the second powder delivery pipe; the air supply valve supplies air to the gap through the alarm pipe of the second powder delivery pipe; the treatment of the abrasion of the inner pipe of the second powder delivery pipe is completed, that is, the alarm and backwashing are realized. The so-called backwashing means blowing the gas from the outside of the powder delivery pipe into the powder delivery pipe. Preferably, the air supply pressure of the air supply valve is adjusted by the pressure regulating valve to be 0.03-0.1 MPa higher than the carrier gas pressure in the second powder delivery pipe. After the pipe wall is abraded and the carrier gas leaks, the pressure regulating valve adjusts the pressure of the backwashing gas source according to the gas pressure in the alarm pipe shown by the air pressure alarm instrument, so that the pressure of the backwashing gas source is 0.03-0.1 MPa higher than the pressure in the alarm pipe (i.e., the carrier gas pressure), and then the air supply valve is opened to blow the gas of the backwashing gas source into the alarm pipe, and the backwashing gas enters the second powder delivery pipe through the gap and the abrasion opening. Similarly, the third powder delivery pipe is the same, which can be understood by those skilled in the art.

[0009] The creativity of the present invention lies in disclosing the structure of the second powder delivery pipe. Through the inner pipe, the outer pipe and the filter cloth coated on the outer wall of the inner pipe, combined with the outer pipe sleeved outside the inner pipe and having a gap between the inner pipe, this innovative structure realizes the technical effects of abrasion alarm and balanced air flow, which are not thought of and not mentioned in the prior art. In actual production, the powder delivery pipe at the position of the second powder delivery pipe of the present invention is more likely to be worn than other parts. Maybe due to the relationship of the conveying position, the prior art has no countermeasures, and only replacement can be carried out after inspection and discovery of abrasion, which is likely to cause steelmaking accidents and increase the loss of other components. The present invention adopts a new technical idea. When the powder abrades the inner pipe, the filter cloth is used to block the powder to avoid leakage, keep the powder amount sprayed into the converter basically unchanged, and more importantly, avoid the powder from wearing other components. By connecting an air pressure gauge outside through the alarm pipe on the shell, it is easier to find the damage of the pipe wall. Further, the externally connected air pressure alarm instrument can give sound and light warnings and display the pressure, realizing the effect of timely alarm for the abrasion of the pipe wall. On the other hand, the alarm pipe is a hollow pipe, externally connected with an air supply valve, then connected with a pressure regulating valve and a backwashing gas source. After the pipe wall is abraded and the carrier gas leaks, the pressure regulating valve adjusts the pressure of the backwashing gas source according to the gas pressure in the alarm pipe, so that the pressure of the backwashing gas source is 0.03-0.1 MPa higher than the pressure in the alarm pipe, and then the air supply valve is opened to blow the gas of the backwashing gas source into the alarm pipe, and the backwashing gas enters the second powder delivery pipe through the abrasion opening, avoiding the continuous leakage of the powder, keeping the powder air flow in the powder delivery pipe stable, and inhibiting the continuous erosion of the powder on the abrasion opening, preventing the abrasion opening from further expanding. The third powder delivery pipe can also have the same structure and effect.

[0010] Preferably, the back-blowing gas is nitrogen; the back-blowing gas source can be an independent, movable gas source, such as a nitrogen bottle, or a fixed gas source in the workshop. The air pressure alarm has the function of alarming and displaying pressure. After obtaining the carrier gas pressure, the pressure of the pressure regulating valve can be manually adjusted and the back-blowing gas source and the gas supply valve can be opened to realize the back-blowing of gas into the inner tube. The existing conventional controller can also be used to automatically adjust the pressure of the pressure regulating valve and open the back-blowing gas source and the gas supply valve after obtaining the carrier gas pressure signal to realize the back-blowing of gas into the inner tube. The specific operation method is conventional technology.

[0011] In the present invention, the shell is provided with a fluid inlet pipe and a fluid outlet pipe, and the fluid can be a liquid for cooling or a gas for bottom blowing; preferably, the liquid inlet pipe and the gas inlet pipe are independently provided, and the liquid outlet pipe and the gas outlet pipe are independently provided; as common sense, the liquid inlet pipe and the liquid outlet pipe are conventionally connected, and the gas inlet pipe and the gas outlet pipe are conventionally connected.

[0012] In the present invention, a bearing and a sealing ring are provided between the shell and the core shaft. The shell is sleeved on the outside of the core shaft and is rotatably connected to the core shaft through the bearing. The sealing ring improves the sealing effect between the shell and the core shaft.

[0013] Furthermore, the third powder conveying pipe is located in the converter ear axis; the third powder conveying pipe includes an inner pipe, an outer pipe and a filter cloth coated on the outer wall of the inner pipe, the outer pipe is sleeved on the outside of the inner pipe and a gap is provided between the outer pipe and the inner pipe; at the same time, the shell is provided with a third powder conveying pipe alarm pipe, and the third powder conveying pipe alarm pipe is connected to the gap. The prior art does not have any discovery and response measures for the wear of the powder conveying pipe. The pipe breakage can only be known through inspections and powder is found, which is very untimely and has even caused steelmaking accidents or wear of other components. In particular, for a section of the horizontal pipe located in the converter ear axis, it is very difficult to be discovered after the objective position determines that it is very difficult to be discovered after the breakage. The three-layer structure of the powder conveying pipe of the present invention is combined with an alarm pipe, which can collect the carrier gas leaked after the pipe is broken, and can give sound and light warnings in combination with a barometer or a pressure alarm, so as to achieve the effect of timely alarm when the pipe wall is worn; further, the external air supply valve can be used to blow air into the powder conveying pipe to keep the carrier gas stable, and the air supply valve is preferably connected to a pressure regulating valve and a back-blowing air source. The working mode and technical effect of the third powder conveying pipe can refer to the second powder conveying pipe.

[0014] The present invention designs the powder conveying pipe as a structure in which the first powder conveying pipe, the second powder conveying pipe, the third powder conveying pipe, and the fourth powder conveying pipe are connected in sequence. The first powder conveying pipe is the central pipe of the rotary joint, which is short and not easy to be worn, connected to the existing pipeline, and receives external powder; the fourth powder conveying pipe is a vertical structure, most of which is located in the converter ear shaft and is conventionally connected to the converter's own pipeline. Therefore, the structure of the present invention is called a joint, that is, a component connecting the existing pipeline and the converter, which has a rotating function and is called a rotary joint. The four pipes are conventionally connected, and the advantage is that they can be replaced according to the worn position, especially for the second powder conveying pipe that is more easily worn, which is easy to load and unload.

[0015] Furthermore, the rotary joint for converter powder spraying includes a gas pipeline and a liquid pipeline located in the converter ear shaft, and the gas pipeline, the liquid pipeline, and the third powder conveying pipe are separated by a solid space, that is, any two pipes are not in the same channel; as common sense, a channel is opened on the converter ear shaft for laying the powder conveying pipe, the gas pipeline, and the liquid pipeline. The prior art is to open a channel and lay all the pipelines in the channel, which have an impact on each other, especially if one pipeline leaks, which will affect other pipelines and is not easy to replace. As common sense, a liquid inlet pipe, a gas inlet pipe, a liquid outlet pipe, and a gas outlet pipe are arranged on the shell at the same time, and the liquid outlet pipe is conventionally connected to the liquid pipeline, and the gas outlet pipe is conventionally connected to the gas pipeline; when used, the gas pipeline and the liquid pipeline are conventionally connected to the pipeline of the converter.

[0016] The rotary joint for converter powder spraying of the present invention comprises a single-channel rotary joint, a multi-channel rotary joint, a third powder conveying pipe, a fourth powder conveying pipe and a converter trunnion; the central channel of the single-channel rotary joint is the first powder conveying pipe, one end of the single-channel rotary joint is used for rotational connection with the existing pipeline, and the other end is connected to the mandrel of the multi-channel rotary joint; the multi-channel rotary joint comprises a housing, a bearing, a sealing ring, a mandrel, a second powder conveying pipe, an alarm pipe, a fluid inlet pipe, and a fluid outlet pipe, the second powder conveying pipe is located at the center of the mandrel, and is respectively connected to the first powder conveying pipe and the third powder conveying pipe; one end of the mandrel is connected to the single-channel rotary joint, and the other end is connected to the converter trunnion through a flange; one end of the third powder conveying pipe is connected to the second powder conveying pipe through a flange, and the other end is connected to the fourth powder conveying pipe through a thread, and the other end of the fourth powder conveying pipe is used to be connected to the existing converter pipeline. Such a structure enables the powder to enter the converter from the existing pipeline through the first powder conveying pipe, the second powder conveying pipe, the third powder conveying pipe, and the fourth powder conveying pipe, and can rotate with the furnace.

[0017] Furthermore, the second powder conveying pipe and the third powder conveying pipe both include an inner pipe, a filter cloth and an outer pipe, the filter cloth is wrapped on the outer wall surface of the inner pipe, there is a gap between the filter cloth surface and the inner wall surface of the outer pipe, and the gap width can be 1 to 10 mm; the alarm pipe is the second powder conveying pipe alarm pipe and the third powder conveying pipe alarm pipe; the gap of the second powder conveying pipe is connected to the second powder conveying pipe alarm pipe through a hose, and the gap of the third powder conveying pipe is connected to the third powder conveying pipe alarm pipe through a hose; the other ends of the second powder conveying pipe alarm pipe and the third powder conveying pipe alarm pipe are respectively connected to the air pressure alarm, the air supply valve, the pressure regulating valve and the backblowing air source.

[0018] In the present invention, the housing of the multi-channel rotary joint is provided with a plurality of fluid inlet pipes and fluid outlet pipes, and the fluid inlet pipes and the fluid outlet pipes correspond to each other and are connected. The air pressure alarm, the air supply valve are connected to the alarm pipe, the air supply valve, the pressure regulating valve and the backflush air source are connected. After the pipe wall is worn through and the carrier gas leaks, the pressure regulating valve adjusts the pressure of the backflush air source according to the gas pressure in the alarm pipe, then opens the air supply valve to blow the gas of the backflush air source into the alarm pipe, and then into the inner pipe.

[0019] In the present invention, the inside of the converter trunnion includes a central horizontal channel, a vertical channel and a plurality of L-shaped fluid channels. The third powder conveying pipe is placed in the central horizontal channel, the fourth powder conveying pipe is placed in the vertical channel, and the plurality of L-shaped fluid channels are evenly distributed along the circumference of the converter trunnion for placing gas pipes and liquid pipes. The inlet ends of the gas pipes and the liquid pipes are connected to the gas outlet pipes and the fluid outlet pipes on the housing through hoses respectively, and the outlet ends of the gas pipes and the liquid pipes are connected to the converter pipes.

[0020] Once the inner pipe of the second powder conveying pipe or the third powder conveying pipe of the present invention is worn through by the powder to form a hole, the gas conveyed by the inner pipe will pass through the hole and the filter cloth into the gap, and enter the second powder conveying pipe alarm pipe or the third powder conveying pipe alarm pipe through the hose connected to the gap. The powder conveyed by the inner pipe will be intercepted by the filter cloth and cannot enter the gap. The pressure alarm device and the air pressure alarm detect the increase in the pressure in the alarm pipe, and immediately give a wear-through alarm signal, which can timely notify the staff. In the case of connecting an air supply valve, the emergency interlock is triggered, and the air supply valve starts to supply gas to the alarm pipe or the alarm pipe. The gas enters the inner pipe of the powder conveying pipe through the alarm pipe, the hose, the gap, the filter cloth and the hole. On the one hand, it avoids the leakage of the powder-air flow in the inner pipe, and on the other hand, blows the powder away from the hole to avoid further wear of the hole by the powder. After the smelting of this heat is completed, if the second powder conveying pipe alarm pipe alarms, the single-channel rotary joint is removed, the second powder conveying pipe is taken out, and after replacing the new second powder conveying pipe, the single-channel rotary joint is installed again to resume production. If the third powder conveying pipe alarm pipe alarms, the core shaft of the multi-channel rotary joint is disconnected from the converter trunnion, the third powder conveying pipe is disconnected from the fourth powder conveying pipe, the single-channel rotary joint is disconnected from the pipeline, and then the single-channel rotary joint, the multi-channel rotary joint and the third powder conveying pipe are translated outward as a whole. After the third powder conveying pipe is removed from the horizontal channel of the trunnion, the third powder conveying pipe is disconnected from the second powder conveying pipe, and after replacing the new third powder conveying pipe, it is reconnected. Then the single-channel rotary joint, the multi-channel rotary joint and the third powder conveying pipe are translated inward as a whole, the core shaft of the multi-channel rotary joint is connected to the converter trunnion, the third powder conveying pipe is connected to the fourth powder conveying pipe, and the single-channel rotary joint is connected to the pipeline to resume production.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention solves for the first time the problem that the prior art cannot timely and effectively detect the abrasion of the powder conveying pipeline. On the premise of completing the basic function of powder conveying, it realizes the abrasion alarm of the powder conveying pipeline, gives an alarm signal in time, and executes disposal measures to avoid accidents. In particular, the prior art can only detect when the powder leaks to a visible place after abrasion, and at that time, a steelmaking accident has already occurred or other components have been worn. The present invention makes a noise through the alarm pipe, especially through the air pressure alarm, and can give an abrasion signal in time for the staff to take corresponding measures.

[0023] (2) The present invention discloses for the first time an emergency disposal method after the abrasion of the powder conveying pipeline. Adjust the pressure of the backflush air source according to the pressure in the alarm pipe, make the pressure of the backflush air source slightly higher than the pressure in the alarm pipe, and then open the air supply valve to start backflushing, which can effectively control the flow rate of the backflush gas, avoid the impact on the powder air flow in the powder conveying pipeline caused by too large a flow rate, and can also reduce the pollution of the molten steel in the converter caused by the backflush gas being blown into the converter.

[0024] (3) The present invention discloses for the first time a powder conveying pipe with a three-layer structure. Even if the powder conveying pipeline is abraded, it can prevent the powder from leaking, avoid the damage of other devices or components caused by the powder leakage, and only need to replace the inner pipe of the powder conveying pipeline after abrasion, with lower maintenance costs.

[0025] (4) The present invention is a multi-section split structure, and the connection method between each part is simple. Welding is not required during the disassembly and installation process, saving replacement time.

[0026] (5) The conventional fluids such as gas and cooling water of the present invention are conveyed through the L-shaped fluid channels on the circumference of the converter trunnion, avoiding the situation that all pipelines occupy the central channel of the converter trunnion. On the one hand, it solves the situation of overcrowded or insufficient space in the central channel, and on the other hand, it greatly reduces the difficulty of overhauling or replacing pipelines.

[0027] (6) The powder conveying pipeline is arranged in the central channel of the converter trunnion, and the conventional fluids such as gas and cooling water are conveyed through the L-shaped fluid channels on the circumference of the converter trunnion, which can isolate the medium in the powder conveying channel from the media such as gas and cooling water, with higher safety. Brief Description of the Drawings

[0028] Figure 1 Schematic diagram of the rotary joint structure for converter powder injection in Embodiment 1;

[0029] Figure 2 Schematic diagram of the structure of the second powder conveying pipe;

[0030] Figure 3 Schematic diagram of the structure of the third powder conveying pipe;

[0031] Figure 4 Schematic diagram of the rotary joint structure for converter powder injection in Embodiment 2;

[0032] Figure 5 Schematic diagram of the rotary joint structure for converter powder injection in Example 3;

[0033] Figure 6 Schematic diagram of the rotary joint structure for converter powder injection in Example 4;

[0034] Figure 7 Schematic diagram of the rotary joint structure for converter powder injection in Example 5;

[0035] Among them: single-channel rotary joint 1, rotary joint 11, first powder delivery pipe 12, multi-channel rotary joint 2, housing 21, core shaft 22, second powder delivery pipe 23, inner pipe 231, outer pipe 232, filter cloth 233, gap 234, hose 235, second powder delivery pipe alarm pipe 24, liquid inlet pipe 25, gas inlet pipe 26, liquid outlet pipe 27, gas outlet pipe 28, bearing 29, sealing ring 20, third powder delivery pipe 3, third powder delivery pipe alarm pipe 31, hose 32, inner pipe 33, outer pipe 34, filter cloth 35, gap 36, fourth powder delivery pipe 4, converter trunnion 5, gas pipeline 51, liquid pipeline 52, air pressure alarm instrument 6, gas supply valve 7, pressure regulating valve 8, backflush gas source 9, air pressure alarm instrument 61, gas supply valve 71, pressure regulating valve 81, backflush gas source 91. Specific implementation mode

[0036] All specific components involved in the present invention are commercially available conventional products, and the specific connection methods and usage methods are all conventional technologies; the powder delivery function of the rotary joint of the present invention is the same as that of the existing ones. The creativity lies in that the powder does not leak after the pipe is broken, an alarm can be given in time and emergency treatment can be carried out after the pipe is broken, and it is easy to replace, and the solid intervals of the pipelines in the converter trunnion do not affect each other.

[0037] Example 1

[0038] See Figure 1 、 Figure 2 :

[0039] The rotary joint for converter powder injection is composed of the following components:

[0040] Single-channel rotary joint 1, multi-channel rotary joint 2, third powder delivery pipe 3, fourth powder delivery pipe 4, converter trunnion 5; The single-channel rotary joint consists of a rotary joint 11 and a first powder delivery pipe 12 located inside the rotary joint; The multi-channel rotary joint consists of a housing 21, a mandrel 22, a second powder delivery pipe 23, and a second powder delivery pipe alarm pipe 24; The second powder delivery pipe includes an inner pipe 231, an outer pipe 232, and a filter cloth 233 coated on the outer wall of the inner pipe. The outer pipe is sleeved outside the inner pipe and there is a gap 234 between the outer pipe and the inner pipe, and the width of the gap is 3 mm; The housing is provided with a liquid inlet pipe 25, a gas inlet pipe 26, a liquid outlet pipe 27, and a gas outlet pipe 28; There are a bearing 29 and a sealing ring 20 between the housing and the mandrel; Inside the converter trunnion, there are a gas pipeline 51 and a liquid pipeline 52;

[0041] The first powder delivery pipe, the second powder delivery pipe, the third powder delivery pipe, and the fourth powder delivery pipe are connected in sequence; One end of the mandrel is connected to the rotary joint, and the other end is connected to the converter trunnion; The housing is sleeved outside the mandrel and is rotationally connected to the mandrel; The second powder delivery pipe is located inside the mandrel; The second powder delivery pipe alarm pipe is connected to the gap through a hose 235, and the alarm pipe is a conventional hollow pipe; The fluid can be liquid for cooling and gas for bottom blowing; As common knowledge, the liquid inlet pipe, the liquid outlet pipe, and the liquid pipeline are conventionally connected, and the gas inlet pipe, the gas outlet pipe, and the gas pipeline are conventionally connected; The housing is sleeved outside the mandrel and is rotationally connected to the mandrel through the bearing, and the sealing ring improves the sealing effect between the housing and the mandrel;

[0042] There is a solid interval between the gas pipeline, the liquid pipeline, and the third powder delivery pipe, that is, any two pipes are not in the same channel; As common knowledge, channels are opened on the converter trunnion for laying the powder delivery pipe, the gas pipeline, and the liquid pipeline. In the prior art, one channel is opened and all the pipes are laid in this channel, which affects each other. Especially, if one pipe leaks, it will affect other pipes, and it is not easy to replace;

[0043] The inside of the converter trunnion includes a central horizontal channel, a vertical channel, and two L-shaped fluid channels, and the L-shaped fluid channels are evenly distributed along the circumference of the converter trunnion; The third powder delivery pipe is placed in the central horizontal channel, the fourth powder delivery pipe is placed in the vertical channel, and the L-shaped fluid channels are used to place the gas pipeline and the liquid pipeline. The inlet ends of the gas pipeline and the liquid pipeline are connected to the gas outlet pipe and the fluid outlet pipe on the housing through hoses respectively. During application, the outlet ends of the gas pipeline and the liquid pipeline are connected to the converter pipeline.

[0044] Embodiment 2

[0045] For the rotary joint for converter powder injection, on the basis of Embodiment 1, the third powder delivery pipe includes an inner pipe 33, an outer pipe 34, and a filter cloth 35 coated on the outer wall of the inner pipe (the structure is shown in Figure 3), the outer tube is sleeved outside the inner tube and there is a gap 36 between the outer tube and the inner tube, and the width of the gap is 5 mm; at the same time, the housing is provided with a third powder conveying pipe alarm pipe 31, and the third powder conveying pipe alarm pipe is communicated with the gap through a hose 32; the rest is the same as that of the first embodiment, see Figure 4 。

[0046] Embodiment Three

[0047] The rotatable joint for alarmable converter powder injection, on the basis of the first embodiment, adds a pneumatic alarm instrument 6 and a gas supply valve 7. One end of the second powder conveying pipe alarm pipe is communicated with the gap through a hose 235, and the other end is connected with a pneumatic alarm instrument and a gas supply valve. The rest is the same as that of the first embodiment, see Figure 5 ; after the pipe wall is worn through and the carrier gas leaks, the pneumatic alarm instrument gives a warning, and then the gas supply valve is opened to blow the backflush gas into the alarm pipe. The backflush gas enters the second powder conveying pipe through the worn-through opening to prevent the powder from leaking out continuously. The backflush gas is nitrogen.

[0048] Embodiment Four

[0049] The rotatable joint for alarmable converter powder injection, on the basis of the third embodiment, adds a pressure regulating valve 8 and a backflush gas source 9. One end of the second powder conveying pipe alarm pipe is communicated with the gap through a hose, and the other end is connected with a pneumatic alarm instrument, a gas supply valve. The gas supply valve, the pressure regulating valve and the backflush gas source nitrogen cylinder are connected in sequence; the rest is the same as that of the third embodiment, see Figure 6 。After the pipe wall is worn through and the carrier gas leaks, the pressure regulating valve adjusts the pressure of the backflush gas source according to the gas pressure in the alarm pipe, so that the pressure of the backflush gas source is 0.03 - 0.05 MPa higher than the pressure in the alarm pipe. Then the gas supply valve is opened to blow the gas of the backflush gas source into the alarm pipe. The backflush gas enters the second powder conveying pipe through the worn-through opening to prevent the powder from leaking out continuously, keep the air flow stable, and avoid the extrusion of the powder at the worn-through opening to prevent the worn-through opening from further expanding; the backflush gas is nitrogen.

[0050] Embodiment Five

[0051] The rotatable joint for alarmable converter powder injection, on the basis of the second embodiment, adds a pneumatic alarm instrument, a gas supply valve, a pressure regulating valve and a backflush gas source for the second powder conveying pipe, and a pneumatic alarm instrument, a gas supply valve, a pressure regulating valve and a backflush gas source for the third powder conveying pipe; one end of the second powder conveying pipe alarm pipe is communicated with the gap through a hose 235, and the other end is connected with a pneumatic alarm instrument 6, a gas supply valve 7. The gas supply valve 7, the pressure regulating valve 8, the backflush gas source 9 (nitrogen cylinder) are connected in sequence; one end of the third powder conveying pipe alarm pipe is communicated with the gap through a hose 32, and the other end is connected with a pneumatic alarm instrument 61, a gas supply valve 71. The gas supply valve, the pressure regulating valve 81, the backflush gas source 91 (nitrogen cylinder) are connected in sequence; the rest is the same as that of the second embodiment, see Figure 7 。

[0052] The creativity of the present invention lies in disclosing the structure of the second powder conveying pipe, which is composed of an inner pipe, an outer pipe and a filter cloth wrapped on the outer wall of the inner pipe, in combination with the outer pipe sleeved on the outside of the inner pipe and a gap provided between the outer pipe and the inner pipe. This innovative structure realizes the technical effects of wear alarm and balanced airflow through backblowing, which is not thought of or mentioned in the prior art. In actual production, the powder conveying pipe located at the second powder conveying pipe position of the present invention is more susceptible to wear than other parts. Perhaps due to the conveying position, the prior art has no countermeasures and can only be replaced after wear is found during inspection, which leads to steelmaking accidents and increases the loss of other components. The present invention adopts a new technical idea. When the powder wears out the inner tube, the existing filter cloth is used to block the powder to prevent leakage, keep the powder dosage unchanged, and prevent the powder from wearing other parts. Through the external pressure gauge, it is easier to find the damage of the tube wall. Furthermore, the external air pressure alarm can give sound and light warnings, thereby achieving the effect of timely alarm when the tube wall is worn out. On the other hand, the alarm tube is a hollow tube with an external air supply valve, which can supply air to the tube after the tube wall is worn out and the carrier gas leaks, thereby maintaining a stable airflow and avoiding the pushing of the powder at the worn-out opening, thereby preventing the worn-out opening from further expanding.

[0053] The prior art does not have any detection and countermeasures for the wear and tear of the powder conveying pipe. The pipe can only be known to be broken when the powder is found through inspection, which is very untimely and may even cause steelmaking accidents or wear and tear of other components. In particular, for a section of the horizontal pipe located in the ear axis of the converter (the third powder conveying pipe position of the present invention), it is very difficult to be discovered after the break due to the objective position. The three-layer structure of the powder conveying pipe of the present invention is combined with an alarm pipe, which can collect the carrier gas leaked after the pipe is broken. In combination with a barometer or a pressure alarm, sound and light warnings can be given, achieving the effect of timely alarm when the pipe wall is worn; further, air can be blown into the powder conveying pipe through an external air supply valve to keep the carrier gas stable. The air pressure alarm is used in conjunction with the air supply valve, the pressure regulating valve, and the back-blowing gas source. Once the powder conveying pipe is worn and ruptured, the pressure regulating valve can adjust the back-blowing gas source pressure according to the pressure in the alarm pipe, so that the back-blowing gas source pressure is slightly higher than the pressure in the alarm pipe, and then the air supply valve is opened to spray the back-blowing gas into the alarm pipe.

[0054] The present invention designs the powder conveying pipe as a structure in which the first powder conveying pipe, the second powder conveying pipe, the third powder conveying pipe, and the fourth powder conveying pipe are connected in sequence. The first powder conveying pipe is the central pipe of the rotary joint, which is short and not easy to be worn, connected to the existing pipeline, and receives external powder; the fourth powder conveying pipe is a vertical structure, most of which is located in the converter ear shaft and is conventionally connected to the converter's own pipeline. Therefore, the structure of the present invention is called a joint, that is, a component connecting the existing pipeline and the converter, which has a rotating function and is called a rotary joint. The four pipes are conventionally connected, and the advantage is that they can be replaced according to the worn position, especially for the second powder conveying pipe that is more easily worn, which is easy to load and unload.

[0055] In application, the rotary joint for converter powder injection of the present invention includes a single-channel rotary joint, a multi-channel rotary joint, a third powder delivery pipe, a fourth powder delivery pipe, and a converter trunnion; the central channel of the single-channel rotary joint is the first powder delivery pipe, one end of the single-channel rotary joint is used for rotatably connecting with an existing pipeline, and the other end is connected to the mandrel of the multi-channel rotary joint; the multi-channel rotary joint includes a housing, bearings, sealing rings, a mandrel, a second powder delivery pipe, an alarm pipe, a fluid inlet pipe, and a fluid outlet pipe. The second powder delivery pipe is located in the center of the mandrel and is respectively communicated with the first powder delivery pipe and the third powder delivery pipe; one end of the mandrel is connected to the single-channel rotary joint, and the other end is connected to the converter trunnion through a flange; one end of the third powder delivery pipe is connected to the second powder delivery pipe through a flange, and the other end is connected to the fourth powder delivery pipe through a thread. The other end of the fourth powder delivery pipe is used for connecting with an existing converter pipeline. Such a structure enables the powder to enter the converter through the existing pipeline, the first powder delivery pipe, the second powder delivery pipe, the third powder delivery pipe, and the fourth powder delivery pipe, and can rotate with the furnace.

[0056] In the present invention, the filter cloth is bonded to the outer wall of the inner pipe by an adhesive, and then the outer pipe and both ends of the inner pipe are conventionally closed and connected to form the second powder delivery pipe or the third powder delivery pipe, which is a conventional technology. The filter cloth is bonded to the surface of the inner pipe by an adhesive; the adhesive includes epoxy resin, diamine curing agent, and diluent. Apply an adhesive composed of epoxy resin (E-51), diamine curing agent (isophorone diamine), and diluent (dibutyl sebacate) with a mass ratio of 100:35:10 on one side of the filter cloth, then wrap the filter cloth around the outer wall of the inner pipe and place it at room temperature for 24 hours to bond the filter cloth to the outer wall of the inner pipe. Compared with sleeving the filter cloth on the outer wall of the inner pipe, the gluing method can prevent powder from entering between the filter cloth and the outer wall of the inner pipe after the inner pipe is worn. The adhesive can also be cured by heating, which is a conventional technology. The filter cloth is an existing product and can block powder, such as cotton filter cloth and polyester filter cloth.

[0057] In the present invention, the housing of the multi-channel rotary joint is provided with a plurality of fluid inlet pipes and fluid outlet pipes, and the fluid inlet pipes and fluid outlet pipes correspond to each other and are communicated, which is schematically described in the embodiment.

[0058] Comparative Example 1

[0059] For the rotary joint for converter powder injection, on the basis of Embodiment 1, the second powder delivery pipe is of a single-pipe structure, without a filter cloth and an outer pipe, and the housing is not provided with an alarm pipe for the second powder delivery pipe; the rest is the same as Embodiment 1.

[0060] Comparative Example 2

[0061] For the rotary joint for converter powder injection, on the basis of Embodiment 1, the filter cloth of the second powder delivery pipe is wrapped around the outer wall of the inner pipe and fixed with fastening pieces (the fixed positions are at both ends and in the middle, without gluing); the rest is the same as Embodiment 1.

[0062] Embodiment 6

[0063] The rotary joint for converter powder injection, on the basis of Embodiment 3, has no gas supply valve; the rest is the same as Embodiment 3.

[0064] Application Example

[0065] The simulated rotary joint is applied in the steelmaking process. The lime powder flow rate is 80 kg / min, and the carrier gas flow rate is 20 Nm 3 / min. Taking the actual steelmaking time as one furnace charge, the powder injection is started and stopped normally. Parallel experiments are carried out on each rotary joint, starting from a new converter.

[0066] Using the rotary joint of Embodiment 1 of the present invention, at the 6000th furnace charge, a hole appears in the second powder delivery pipe, and the alarm pipe emits an alarm signal, which is noticed by the staff. Due to a small amount of powder-carrying gas leaking from the alarm pipe, the back pressure of the powder delivery pipe drops by 0.01 MPa, but the normal smelting of the converter can still be maintained; during the smelting process, due to the continuous erosion of the powder on the hole, the hole gradually becomes larger, and the back pressure of the powder delivery pipe drops slowly accordingly. By the end of this furnace charge, the back pressure of the powder delivery pipe drops by 0.02 MPa. After the end of this furnace charge, the second powder delivery pipe is replaced. After disassembling, it is found that the hole size reaches 3 mm, and the filter cloth at the hole is covered with powder, but there is no powder at the gap. The quality of the molten steel after steelmaking meets the requirements, but it has reached the lower-middle level of the quality standard.

[0067] Using the rotary joint of Embodiment 3 of the present invention, at the 6080th furnace charge, a hole appears in the second powder delivery pipe, and the air pressure alarm instrument rings loudly. The staff immediately notices. At the same time, the gas supply valve cooperating with the gas alarm instrument sprays nitrogen into the alarm pipe (opening the nitrogen cylinder). The nitrogen enters the powder delivery pipe along the alarm pipe, gap, and hole, avoiding the drop of the back pressure of the powder delivery pipe, forming a gas film protection at the hole, and preventing the powder from continuously impacting the hole and causing the hole to expand. By the end of this furnace charge, after disassembling, it is found that the hole size is only 1.5 mm, there is a small amount of powder on the filter cloth at the hole, and there is no powder at the gap. The quality of the molten steel after steelmaking meets the requirements and reaches the middle level of the quality standard.

[0068] Using the rotary joint of the fourth embodiment of the present invention, at the 6100th furnace charge, a hole appeared in the second powder delivery pipe, and the air pressure alarm sounded loudly. The staff immediately noticed. At the same time, the gas supply valve, pressure regulating valve, and backflush gas source cooperating with the gas alarm implemented emergency disposal measures, and blew a small flow of nitrogen into the alarm pipe (the air pressure was greater than the carrier gas pressure by 0.03 MPa). The nitrogen entered the powder delivery pipe along the alarm pipe, gap, and hole, preventing the back pressure of the powder delivery pipe from dropping, forming an air film protection at the hole, and preventing the powder from continuously impacting the hole and causing the hole to expand. When the furnace charge ended and it was disassembled, the hole size was only 1 mm, there was no powder on the filter cloth at the hole, and there was no powder in the gap. The quality of the molten steel after steelmaking met the requirements and reached the upper-middle level of the quality standard. Compared with the third embodiment, the fourth embodiment can control the pressure difference between the backflush gas and the carrier gas, and avoid affecting the powder injection flow rate under the condition of maintaining the carrier gas balance, which is beneficial to maintaining the quality of the molten steel.

[0069] Using the rotary joint of Comparative Example 2, at the 6010th furnace charge, a hole appeared in the second powder delivery pipe, and the alarm pipe sent out an alarm signal. The staff noticed and the normal smelting of the converter could still be maintained; during the smelting process, due to the continuous erosion of the hole by the powder, the hole gradually became larger, and the back pressure of the powder delivery pipe slowly decreased. After the smelting of this furnace charge ended, the second powder delivery pipe was replaced. When disassembled, the hole size reached 3.6 mm, the filter cloth at the hole was covered with powder, and there was a small amount of powder (around the hole) in the gap. The quality of the molten steel after steelmaking met the requirements, but it had reached the lower limit of the quality standard.

[0070] Using the rotary joint of Comparative Example 1, at the 6055th furnace charge, a hole appeared in the second powder delivery pipe, and the staff did not notice. When the furnace charge ended, it was found that the phosphorus content of the molten steel was high, the basicity of the slag was significantly low, and the content of (CaO) in the slag was lower than the theoretical value. It was judged that the powder delivery pipe was worn out and a large amount of lime powder overflowed; upon inspection of the multi-channel rotary joint, it was found that a hole appeared in the second powder delivery pipe, and the lime powder leaked from the powder delivery pipe into the inner cavity of the mandrel. A large amount of lime powder had accumulated inside the mandrel, and the size of the hole in the powder delivery pipe had reached 5 mm; at this time, the multi-channel rotary joint had to be removed for cleaning and repair, delaying the production time. The quality of the molten steel after steelmaking did not meet the requirements.

Claims

1. Rotating joint for alarming converter powder injection, characterized in that, the rotating joint for alarming converter powder injection includes a single-channel rotating joint, a multi-channel rotating joint, a third powder conveying pipe, a fourth powder conveying pipe, a converter trunnion, a pneumatic alarm, and a gas supply valve; the single-channel rotating joint includes a rotating joint and a first powder conveying pipe located inside the rotating joint; the multi-channel rotating joint includes a housing, a mandrel, a second powder conveying pipe, and a second powder conveying pipe alarm pipe; one end of the mandrel is connected to the rotating joint and the other end is connected to the converter trunnion; the housing is sleeved outside the mandrel and is rotatably connected to the mandrel; the second powder conveying pipe is located inside the mandrel; the second powder conveying pipe includes an inner pipe, an outer pipe, and a filter cloth coated on the outer wall of the inner pipe, the outer pipe is sleeved outside the inner pipe and there is a gap between the outer pipe and the inner pipe, and the width of the gap is 3 mm; one end of the second powder conveying pipe alarm pipe is communicated with the gap, the other end is connected with a pneumatic alarm and a gas supply valve; the first powder conveying pipe, the second powder conveying pipe, the third powder conveying pipe, and the fourth powder conveying pipe are communicated in sequence; the gas supply valve is connected with a pressure regulating valve; the pressure regulating valve is connected with a backflush gas source; the filter cloth is adhered to the outer wall of the inner pipe by an adhesive, and the adhesive includes epoxy resin, diamine curing agent, and diluent; the gas supply pressure of the gas supply valve is adjusted by the pressure regulating valve to be 0.03 MPa higher than the carrier gas pressure in the second powder conveying pipe; there are a gas pipeline and a liquid pipeline in the converter trunnion; there is a solid interval between the gas pipeline, the liquid pipeline, and the third powder conveying pipe.

2. The rotating joint for alarming converter powder injection according to claim 1, characterized in that, the housing is provided with a fluid inlet pipe; there are a bearing and a sealing ring between the housing and the mandrel.

3. The rotating joint for alarming converter powder injection according to claim 2, characterized in that, the fluid inlet pipe includes a liquid inlet pipe and a gas inlet pipe; the fluid outlet pipe includes a liquid outlet pipe and a gas outlet pipe.

4. The rotating joint for alarming converter powder injection according to claim 1, characterized in that, the third powder conveying pipe includes an inner pipe, an outer pipe, and a filter cloth coated on the outer wall of the inner pipe, the outer pipe is sleeved outside the inner pipe and there is a gap between the outer pipe and the inner pipe; the housing is provided with a third powder conveying pipe alarm pipe, and the third powder conveying pipe alarm pipe is communicated with the gap.

5. Method for dealing with abrasion of the inner pipe of the second powder conveying pipe by the rotating joint for alarming converter powder injection according to claim 1, characterized in that, after the inner pipe of the second powder conveying pipe is abraded, the carrier gas leaks to the pneumatic alarm, triggering the pneumatic alarm to alarm; the powder is blocked inside the inner pipe of the second powder conveying pipe by the filter cloth; the gas supply valve supplies gas to the gap through the second powder conveying pipe alarm pipe; the treatment of the abrasion of the inner pipe of the second powder conveying pipe is completed; the gas supply pressure of the gas supply valve is adjusted by the pressure regulating valve to be 0.03 MPa higher than the carrier gas pressure in the second powder conveying pipe.

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