Control method for automatic speed increasing and decreasing of dust removal fan

Abstract

The invention provides a control method for automatic speed increasing and decreasing of a dust removal fan. The control method comprises the following steps that firstly, relevant data of an LF furnace are collected in real time; 2, according to the related data conditions, the current LF furnace production state is judged; and thirdly, according to the current LF furnace production state, the rotating speed gear of the dust removal fan is dynamically adjusted. According to the method, the rotating speed gear of the dust removal fan is adjusted only when the current production state changes clearly and periodically, frequent adjustment is not needed, the number of times of starting, stopping and speed changing of the motor is greatly reduced, mechanical stress, bearing abrasion and frequency converter switching loss are remarkably reduced, and therefore the overall service life of the fan, the motor and the frequency converter is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of LF furnace dust removal, and in particular to a method for controlling the automatic speed increase and decrease of a dust removal fan. Background Art

[0002] LF furnace is a secondary refining equipment commonly used in steel metallurgy. It is mainly used for further refining of molten steel after primary refining in a converter or electric furnace. In the steelmaking production line, LF furnace is an important equipment component in the refining process. LF furnace mainly heats the molten steel by heating with graphite electrodes, and at the same time adds raw materials such as silicon manganese, lime, pre-melted slag, and nickel iron to adjust the alloy cost. Dust will be generated during the smelting process, and the dust removal fan is an important environmental protection equipment supporting the LF furnace. Dust removal by dust removal fan is an indispensable part of the smelting process.

[0003] In the actual production process, in order to ensure the dust removal effect, most companies adopt a long-term high-speed operation during production, and manually adjust the fan to a low speed or stop it when the furnace is stopped or production is stopped. The speed is generally not adjusted during the production process or is adjusted manually. The fan speed is not adjusted according to the production rhythm and smelting status, resulting in obvious waste of electricity. At the same time, because the dust removal fan is in a high-speed state, the graphite electrode is weathered during the smelting gap, and some powdered materials (such as lime) are easily sucked away by the fan, resulting in the problem of waste of raw materials.

[0004] In the existing technology, PID algorithm is usually used to control the fan speed in real time through the frequency converter. Although this can achieve the coordinated cooperation between the dust removal fan and the production rhythm and avoid energy waste, the smelting conditions are often accompanied by dust, high temperature, and electromagnetic interference. The PID algorithm may cause frequent misadjustments due to interference, and requires high-precision frequency converters, real-time sensor networks and complex controllers to cooperate with each other. Frequent adjustment of the dust removal fan speed through the frequency converter will increase the loss of the dust removal fan and the frequency converter, and increase the overall failure rate of the dust removal system. Summary of the Invention

[0005] The present invention is made in view of the above problems, and its purpose is to provide a control method for automatically raising and lowering the speed of a dust removal fan, which can dynamically adjust the speed of the dust removal fan according to the production rhythm and smelting status, thereby meeting the dust removal requirements, reducing operating power consumption, and reducing the consumption of electrodes and pulverized materials.

[0006] Specifically, a first aspect of the present invention provides a method for controlling the automatic speed increase and decrease of a dust removal fan, comprising the following steps: Step 1: Real-time collection of relevant data of LF furnace; Step 2: judging the current LF furnace production status according to the relevant data; Step 3: Dynamically adjust the dust removal fan speed gear according to the current LF furnace production status.

[0007] Furthermore, the relevant data of the LF furnace include the position of the ladle transport vehicle, the position of the furnace cover, the position of the electrode, the electrode power supply current, and the status of the feeding valve of the LF furnace.

[0008] The LF furnace (Ladle Furnace) is a crucial secondary refining equipment in steel metallurgy. It is mainly responsible for heating the molten steel, fine-tuning the composition (alloying), desulfurization, deoxidation, removing inclusions, and uniforming the composition and temperature of the molten steel.

[0009] Furthermore, the positions of the ladle transport vehicle include smelting positions and non-smelting positions.

[0010] The ladle must be accurately transported and positioned to the working position (i.e., smelting position) below the LF furnace. After the ladle transport vehicle reaches the smelting position, the block welded on the transport vehicle will trigger the limit switch. At this time, the collected position of the ladle transport vehicle is set to the smelting position, otherwise it is the non-smelting position.

[0011] The center of the ladle must be strictly aligned with the center of the furnace cover and the center of the electrode. If the alignment is poor, the arc generated by the electrode will deviate to one side of the ladle wall, resulting in uneven heating of the molten steel, reduced heating efficiency, and prolonged heating time. Arc deflection will cause the arc to directly burn local areas of the ladle lining, accelerating the melting loss of the refractory material in that area, shortening the life of the ladle, increasing the cost of the refractory material, and possibly melting the refractory material into the molten steel and contaminating the steel quality.

[0012] Furthermore, the furnace cover position includes an upper limit position, a lower limit position and other positions.

[0013] The airtightness of the furnace cover is the physical guarantee for the LF furnace to realize its core refining functions (especially desulfurization, oxygen control, and prevention of air inhalation). When the furnace cover is at the lower limit position, it means that the LF furnace is in the heating preparation or heating state. When the furnace cover is at the upper limit position, it means that the heating has ended or is still in the smelting preparation state. The upper limit switch and the lower limit switch are used to determine whether the corresponding position has been reached.

[0014] Furthermore, the electrode position includes an upper limit position and a non-upper limit position.

[0015] The electrode position (usually automatically adjusted by the electrode lifting mechanism) directly determines the arc length. An arc that is too short (electrode inserted too deeply) can cause a short circuit or arc burial, resulting in large current fluctuations, low thermal efficiency, and even equipment damage. An arc that is too long (electrode raised too high) results in excessive heat dissipation, low thermal efficiency, arc instability, high noise, and increased radiant heat to the ladle lining. A stable arc is the foundation for efficient and uniform heating. Electrode position affects the arc's heating area on the molten steel surface. Proper distribution contributes to a uniform temperature of the molten steel.

[0016] When the electrode is at the upper limit, it is far away from the molten steel, and it is in the smelting preparation state or smelting completion state. When the electrode is not at the upper limit, it has entered the smelting process, and the current sent by the electrode is used to determine whether it is in the heating state.

[0017] The magnitude of the electrode power supply current directly determines the temperature rise rate of the molten steel. In the non-heating state, the magnitude of the electrode power supply current is 20A~40A, and in the heating state, the magnitude of the electrode power supply current is 30KA~40KA. Therefore, the magnitude of the electrode power supply current can be used to determine whether it is in the heating state.

[0018] Furthermore, the feeding valve state includes whether the feeding valve is open or closed.

[0019] In the smelting and feeding state, the feeding valve is open, otherwise the feeding valve is closed.

[0020] Furthermore, the step 2 specifically includes: If the ladle transport vehicle is at the smelting position, the furnace cover is at the upper limit, and the electrode is at the upper limit, the current LF furnace production state is determined to be the smelting preparation state; If the ladle transport vehicle is at the smelting position, the furnace cover is at the lower limit position, and the charging valve is open, the current LF furnace production state is determined to be the smelting and charging state; If the ladle transport vehicle is at the smelting position and the furnace cover is at the lower limit, the current LF furnace production status is judged to be the smelting waiting state; If the ladle transport vehicle is at the smelting position, the furnace cover is at the lower limit, the electrode is at the non-upper limit, and the electrode power supply current is greater than 1000A, the current LF furnace production state is judged to be the smelting heating state; If the ladle transport vehicle is in a non-smelting position, the furnace cover is at the upper limit, and the electrode is at the upper limit, the current LF furnace production status is determined to be a smelting completion status.

[0021] Furthermore, the step three specifically includes: When the current LF furnace production status is smelting preparation status, adjust the dust removal fan speed gear to low speed gear; When the current LF furnace production status is smelting and charging status, adjust the dust removal fan speed gear to the medium speed gear; When the current LF furnace production status is smelting waiting status, adjust the dust removal fan speed gear to the medium speed gear; When the current LF furnace production state is smelting heating state, adjust the dust removal fan speed gear to high gear; When the current LF furnace production status is the smelting completion status, adjust the dust removal fan speed gear to the low speed gear.

[0022] Furthermore, the speed range corresponding to the speed gear of the dust removal fan is: When the dust removal fan speed gear is low speed gear, the speed is 300r / min~400r / min; When the dust removal fan speed gear is medium speed gear, the speed is 550r / min~650r / min; When the dust removal fan speed gear is high gear, the speed is 750r / min~850r / min. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 is a flow chart of the steps of the present invention; Figure 2 This is the control logic diagram of the present invention.

[0025] The purpose, features and advantages of this drawing will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0027] Obviously, the drawings described below are merely examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios based on these drawings without inventive effort. Furthermore, it is understood that while the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the disclosure of the present invention, any design, manufacturing, or production changes based on the technical content disclosed in the present invention are merely conventional technical means and should not be construed as an inadequacy of the disclosure of the present invention.

[0028] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0029] Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0030] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0031] Unless otherwise specified, the terms "include" and "comprising" used in the present invention may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0032] Unless otherwise specified, the term "or" is inclusive in this disclosure. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0033] In order to better understand the solutions of the embodiments of the present invention, some relevant terms and concepts that may be involved in the embodiments of the present invention are first introduced below.

[0034] (1) LF furnace (Ladle Furnace) is a crucial secondary refining equipment in steel metallurgy. It is mainly used for further refining of molten steel after primary refining in converter or electric furnace. LF furnace is an important equipment component in the refining process of steelmaking production line. LF furnace mainly heats the molten steel by graphite electrode heating, and at the same time adds raw materials such as silicon manganese, lime, pre-melted slag, nickel iron, etc. to adjust the alloy cost.

[0035] (2) A dust removal fan is an industrial environmental protection device that is primarily used to remove dust and pollutants from the air, safeguarding the air quality and human health of the working environment. Its core function is to draw in dust-laden air through the fan's suction force, separate the dust through filtering devices (such as filter bags, electrostatic precipitators, etc.), and finally discharge clean air.

[0036] In this embodiment, Figure 1 As shown, a method for controlling the automatic speed increase and decrease of a dust removal fan comprises the following steps: Step 1: Real-time collection of relevant data of LF furnace; Step 2: judging the current LF furnace production status according to the relevant data; Step 3: Dynamically adjust the dust removal fan speed gear according to the current LF furnace production status.

[0037] Furthermore, the relevant data of the LF furnace include the position of the ladle transport vehicle, the position of the furnace cover, the position of the electrode, the electrode power supply current, and the status of the feeding valve of the LF furnace.

[0038] The LF furnace (Ladle Furnace) is a crucial secondary refining equipment in steel metallurgy. It is mainly responsible for heating the molten steel, fine-tuning the composition (alloying), desulfurization, deoxidation, removing inclusions, and uniforming the composition and temperature of the molten steel.

[0039] Furthermore, the positions of the ladle transport vehicle include smelting positions and non-smelting positions.

[0040] The ladle must be accurately transported and positioned to the working position (i.e., smelting position) below the LF furnace. After the ladle transport vehicle reaches the smelting position, the block welded on the transport vehicle will trigger the limit switch. At this time, the collected position of the ladle transport vehicle is set to the smelting position, otherwise it is the non-smelting position.

[0041] The center of the ladle must be strictly aligned with the center of the furnace cover and the center of the electrode. If the alignment is poor, the arc generated by the electrode will deviate to one side of the ladle wall, resulting in uneven heating of the molten steel, reduced heating efficiency, and prolonged heating time. Arc deflection will cause the arc to directly burn local areas of the ladle lining, accelerating the melting loss of the refractory material in that area, shortening the life of the ladle, increasing the cost of the refractory material, and possibly melting the refractory material into the molten steel and contaminating the steel quality.

[0042] Furthermore, the furnace cover position includes an upper limit position, a lower limit position and other positions.

[0043] The airtightness of the furnace cover is the physical guarantee for the LF furnace to realize its core refining functions (especially desulfurization, oxygen control, and prevention of air inhalation). When the furnace cover is at the lower limit position, it means that the LF furnace is in the heating preparation or heating state. When the furnace cover is at the upper limit position, it means that the heating has ended or is still in the smelting preparation state. The upper limit switch and the lower limit switch are used to determine whether the corresponding position has been reached.

[0044] Furthermore, the electrode position includes an upper limit position and a non-upper limit position.

[0045] The electrode position (usually automatically adjusted by the electrode lifting mechanism) directly determines the arc length. An arc that is too short (electrode inserted too deeply) can cause a short circuit or arc burial, resulting in large current fluctuations, low thermal efficiency, and even equipment damage. An arc that is too long (electrode raised too high) results in excessive heat dissipation, low thermal efficiency, arc instability, high noise, and increased radiant heat to the ladle lining. A stable arc is the foundation for efficient and uniform heating. Electrode position affects the arc's heating area on the molten steel surface. Proper distribution contributes to a uniform temperature of the molten steel.

[0046] When the electrode is at the upper limit, it is far away from the molten steel, and it is in the smelting preparation state or smelting completion state. When the electrode is not at the upper limit, it has entered the smelting process, and the current sent by the electrode is used to determine whether it is in the heating state.

[0047] The magnitude of the electrode power supply current directly determines the temperature rise rate of the molten steel. In the non-heating state, the magnitude of the electrode power supply current is 20A~40A, and in the heating state, the magnitude of the electrode power supply current is 30KA~40KA. Therefore, the magnitude of the electrode power supply current can be used to determine whether it is in the heating state.

[0048] Furthermore, the feeding valve state includes whether the feeding valve is open or closed.

[0049] In the smelting and feeding state, the feeding valve is open, otherwise the feeding valve is closed.

[0050] Furthermore, the step 2 specifically includes: If the ladle transport vehicle is at the smelting position, the furnace cover is at the upper limit, and the electrode is at the upper limit, the current LF furnace production state is determined to be the smelting preparation state; If the ladle transport vehicle is at the smelting position, the furnace cover is at the lower limit position, and the charging valve is open, the current LF furnace production state is determined to be the smelting and charging state; If the ladle transport vehicle is at the smelting position and the furnace cover is at the lower limit, the current LF furnace production status is judged to be the smelting waiting state; If the ladle transport vehicle is at the smelting position, the furnace cover is at the lower limit, the electrode is at the non-upper limit, and the electrode power supply current is greater than 1000A, the current LF furnace production state is judged to be the smelting heating state; If the ladle transport vehicle is in a non-smelting position, the furnace cover is at the upper limit, and the electrode is at the upper limit, the current LF furnace production status is determined to be a smelting completion status.

[0051] Furthermore, the step three specifically includes: When the current LF furnace production status is smelting preparation status, adjust the dust removal fan speed gear to low speed gear; When the current LF furnace production status is smelting and charging status, adjust the dust removal fan speed gear to the medium speed gear; When the current LF furnace production status is smelting waiting status, adjust the dust removal fan speed gear to the medium speed gear; When the current LF furnace production state is smelting heating state, adjust the dust removal fan speed gear to high gear; When the current LF furnace production status is the smelting completion status, adjust the dust removal fan speed gear to the low speed gear.

[0052] In the embodiment of the present invention, the control logic diagram is as follows Figure 2 As shown, the corresponding relationship between the relevant data of the LF furnace in step 2 and step 3 and the current LF furnace production status and the dust removal fan speed gear.

[0053] Furthermore, the speed range corresponding to the speed gear of the dust removal fan is: When the dust removal fan speed gear is low speed gear, the speed is 300r / min~400r / min; When the dust removal fan speed gear is medium speed gear, the speed is 550r / min~650r / min; When the dust removal fan speed gear is high gear, the speed is 750r / min~850r / min.

[0054] In this embodiment, the design speed of the dust removal fan used is 900r / min, the low speed gear is set to 350r / min, the medium speed gear is set to 600r / min, and the high speed gear is set to 800r / min. The specific speed value can be adjusted according to actual production requirements.

[0055] The present invention dynamically adjusts the speed gear of the dust removal fan according to the production rhythm and smelting status, which not only meets the dust removal requirements but also reduces the operating power consumption, avoids the energy waste caused by the dust removal fan being in a high-speed state during production, and reduces the problem of weathering of graphite electrodes in the smelting gap due to the dust removal fan being in a high-speed state, and part of the pulverized material (such as lime) being sucked away by the fan, resulting in waste of raw materials.

[0056] This invention adjusts the dust removal fan speed only when there are clear, periodic changes in the current production status. It eliminates the need for frequent adjustments like PID control. During a relatively stable smelting phase (which can last from a few minutes to over ten minutes), the speed remains constant. This significantly reduces the number of motor starts, stops, and speed changes, significantly reducing mechanical stress, bearing wear, and inverter switching losses. This extends the overall service life of the fan, motor, and inverter, reduces maintenance costs and failure rates, and better aligns with actual production rhythms and needs, offering more timely and predictable responses.

[0057] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the present invention, other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A method for controlling the automatic speed increase and decrease of a dust removal fan, characterized in that: The following steps are involved: Step 1: Real-time collection of relevant data of LF furnace; Step 2: judging the current LF furnace production status according to the relevant data; Step 3: Dynamically adjust the dust removal fan speed gear according to the current LF furnace production status.

2. A method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 1, characterized in that: The relevant data of the LF furnace include the position of the ladle transport vehicle, the position of the furnace cover, the position of the electrode, the electrode power supply current, and the status of the charging valve of the LF furnace.

3. A method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 2, characterized in that: The positions of the ladle transport vehicle include smelting positions and non-smelting positions.

4. A method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 2, characterized in that: The furnace cover position includes an upper limit position, a lower limit position and other positions.

5. The method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 2, characterized in that: The electrode position includes an upper limit position and a non-upper limit position.

6. A method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 2, characterized in that: The feeding valve state includes the feeding valve being open and closed.

7. The method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 1, characterized in that: The second step specifically includes: If the ladle transport vehicle is at the smelting position, the furnace cover is at the upper limit, and the electrode is at the upper limit, the current LF furnace production state is determined to be the smelting preparation state; If the ladle transport vehicle is at the smelting position, the furnace cover is at the lower limit position, and the charging valve is open, the current LF furnace production state is determined to be the smelting and charging state; If the ladle transport vehicle is at the smelting position and the furnace cover is at the lower limit, the current LF furnace production status is judged to be the smelting waiting state; If the ladle transport vehicle is at the smelting position, the furnace cover is at the lower limit, the electrode is at the non-upper limit, and the electrode power supply current is greater than 1000A, the current LF furnace production state is judged to be the smelting heating state; If the ladle transport vehicle is in a non-smelting position, the furnace cover is at the upper limit, and the electrode is at the upper limit, the current LF furnace production status is determined to be a smelting completion status.

8. The method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 1, characterized in that: The step three specifically includes: When the current LF furnace production status is smelting preparation status, adjust the dust removal fan speed gear to low speed gear; When the current LF furnace production status is smelting and charging status, adjust the dust removal fan speed gear to the medium speed gear; When the current LF furnace production status is smelting waiting status, adjust the dust removal fan speed gear to the medium speed gear; When the current LF furnace production state is smelting heating state, adjust the dust removal fan speed gear to high gear; When the current LF furnace production status is the smelting completion status, adjust the dust removal fan speed gear to the low speed gear.

9. The method for controlling the automatic speed increase and decrease of a dust removal fan according to claim 1, characterized in that: The speed range corresponding to the speed gear of the dust removal fan is: When the dust removal fan speed gear is low speed gear, the speed is 300r / min~400r / min; When the dust removal fan speed gear is medium speed gear, the speed is 550r / min~650r / min; When the dust removal fan speed gear is high gear, the speed is 750r / min~850r / min.

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