Operation control method for hot rolling multi-mode dust removal fan

Abstract

The invention discloses a hot rolling multi-mode dust removal fan operation control method, which comprises the following steps of: establishing a dust removal fan operation mode according to an actual working condition in combination with a field detection signal in a process section from dephosphorization to finish rolling and steel throwing of a hot rolling production line; and the operation mode of the dust removal fan is established according to the actual working condition, specifically, maintenance operation adaptive control, roller changing operation adaptive control and normal rolling operation adaptive control of the dust removal fan under the maintenance working condition, the roller changing working condition and the normal rolling working condition are established. The invention discloses an operation control method for a hot rolling multi-mode dust removal fan. The operation control method is technically set around energy consumption reduction; reliable operation is taken as a technical support, and a technical scheme which considers selection of frequency conversion types, control of how to establish operation reliably and reflection of energy consumption reduction in multi-dimensional and multi-level optimization setting of each control link is formed. And the working frequency of the frequency converter is always matched with the production working condition, so that better dust removal and energy conservation effects are achieved.

Description

Technical Field

[0001] The invention belongs to the field of automatic control of metallurgical steel rolling, and in particular relates to an operation control method of a hot rolling multi-mode dust removal fan. Background Art

[0002] The dust removal system on the existing hot rolling production line usually makes the dust removal fan work at the rated speed. Even if there is a variable air volume that adapts to the real-time working conditions, either the variable air volume is achieved by changing the air door opening while maintaining the rated speed; or it is theoretically proposed to achieve real-time variable air volume through frequency conversion control. However, if the former adjustment method of still maintaining the rated speed and using the variable air door opening is adopted, there will be additional waste of large energy consumption; if the variable air volume adjustment is achieved based on the theoretically proposed real-time frequency conversion method, there will be a risk of overcurrent or overvoltage in actual use, which will accelerate the aging of equipment components and cause additional cost burden. At the same time, there are problems of complex settings or complex controls. How to reduce energy consumption in a simple way while maintaining the life of the equipment and not increasing the control or equipment complexity too much has become a problem that requires technical optimization and solution.

[0003] The invention application with the publication number CN1197118A discloses "a fuzzy-controlled fully automatic dust removal system", including a fan, dust removal device accessories, and an industrial control computer and a variable frequency speed regulator. The above equipment is based on the fuzzy control theory and forms a closed-loop control system that automatically tracks and sets the expected value at any time through the industrial control computer. The present invention automatically tracks the smoke concentration during the iron-making period of the blast furnace, and controls the exhaust volume according to the smoke concentration. The dust removal system stops working during the iron-making period of the blast furnace, thereby minimizing the energy consumption of the motor, extending the service life of the motor, and achieving a good dust removal effect.

[0004] The invention application with application number: CN201810139919 7 discloses "a dust removal fan time period control system and a dust removal system modification method", which includes: a human-computer interaction device, connected to an intelligent speed control device, for setting the production time period division time point and the corresponding gas negative pressure gear value D in the intelligent speed control device; an air pressure detection device, installed in the dust collecting pipeline, real-time collecting the actual gas negative pressure value P in the dust collecting pipeline and transmitting it to the intelligent speed control device; an intelligent speed control device, connected to the dust removal fan, determining the production time period of the dust removal system, and comparing the actual gas negative pressure value P and the gas negative pressure gear value D, and adjusting the speed of the dust removal fan according to the comparison result and the most unfavorable principle, so that P is equal to D.

[0005] The invention application with application number: CN201910698294.2 discloses "a dust removal method and device based on a hot rolling process". This method can determine the first dust concentration value and the first difference between the second dust concentration at the flue baffle when the hot rolling four-roll mill rolls the current material to be rolled, and when the first difference reaches a set threshold and the hot rolling four-roll mill completes rolling of the current material to be rolled, before the hot rolling four-roll mill rolls the next material to be rolled, control the flue baffle to move from the initial position to the set position, then control the cleaning equipment to clean the flue baffle, and obtain the target image, and control the flue baffle to move from the set position to the initial position when the target image reaches the cleaning standard. Summary of the invention

[0006] The object of the present invention is to provide a hot rolling dust removal method which reduces energy consumption without reducing the service life of equipment.

[0007] In order to achieve the above technical objectives, the present invention provides a hot rolling multi-mode dust removal fan operation control method, and its technical solution is as follows:

[0008] A hot rolling multi-mode dust removal fan operation control method,

[0009] From the dephosphorization to the finishing and polishing process of the hot rolling production line, the dust removal fan operation mode is established according to the actual working conditions in combination with the on-site detection signals;

[0010] The dust removal fan operation mode is established according to the actual working conditions, specifically:

[0011] Establish maintenance operation adaptation control, roll changing operation adaptation control and normal rolling operation adaptation control of the dust removal fan under maintenance conditions, roll changing conditions and normal rolling conditions respectively.

[0012] Further,

[0013] A dust removal control machine that is independent of the process control machine and the basic automation control machine and is used to establish the maintenance operation adaptation control, roll change operation adaptation control and normal rolling operation adaptation control of the dust removal fan.

[0014] The dust removal control machine can communicate with the process control machine;

[0015] or

[0016] A dust removal control unit is added to the basic automation control machine, and the added dust removal control unit establishes adaptation control for the maintenance operation of the dust removal fan, the roll changing operation adaptation control and the normal rolling operation adaptation control.

[0017] Further,

[0018] When in maintenance condition, the dust removal fan is stopped by the dust removal control machine or dust removal control unit;

[0019] When in the roller changing condition, the dust removal control machine or dust removal control unit controls the dust removal fan status accordingly according to the current roller changing time;

[0020] When in normal rolling conditions, the dust removal fan or dust removal control unit performs corresponding dust removal fan status control according to the on-site detection signal.

[0021] Further,

[0022] When in the roller changing condition, the dust removal control machine or dust removal control unit controls the dust removal fan status accordingly according to the current roller changing time, specifically:

[0023] When the roller replacement time exceeds the set threshold, the dust removal control machine or the dust removal control unit controls the dust removal fan to stop;

[0024] Otherwise, the dust removal fan is put into standby mode by the dust removal control machine or the dust removal control unit.

[0025] Further,

[0026] When the roll is changed for the first stand of rough rolling, the judgment and control are directly carried out according to the roll change exceeding the set threshold;

[0027] When changing the rolls of the second stand of rough rolling, the judgment and control are directly carried out according to the fact that the roll change does not exceed the set threshold;

[0028] When the rollers of the finishing mill are changed, the roller changing time is counted. When the roller changing time exceeds the set threshold, the dust removal control machine or the dust removal control unit controls the dust removal fan to stop; otherwise, the dust removal control machine or the dust removal control unit controls the dust removal fan to standby.

[0029] Further,

[0030] When in normal rolling conditions, the dust removal fan or dust removal control unit performs corresponding dust removal fan status control according to the on-site detection signal, specifically:

[0031] When the dust removal control machine or the dust removal control unit receives the dephosphorization signal of the first strip steel, the dust removal fan is controlled to maintain a standby state with a constant low air volume;

[0032] When the dust removal control machine or the dust removal control unit receives the flying shear signal or the steel biting signal of the first finishing rolling stand or the steel biting signal of the second finishing rolling stand or the steel biting signal of the third finishing rolling stand, the dust removal fan is controlled to enter the variable frequency control state based on the target air volume based on one of the signals;

[0033] When the dust removal control machine or the dust removal control unit receives the steel throwing signal of the last stand of finishing rolling, the dust removal fan is controlled to enter the standby state.

[0034] Further,

[0035] When the dust removal control machine or the dust removal control unit receives the phosphorus removal signal, it controls the dust removal fan to maintain a standby state at a constant low air volume. It also establishes a detection and judgment on whether the dust removal fan is maintained in a standby state at a constant low air volume based on the steel biting signal of the first rough rolling stand. When the detection result shows that the dust removal fan is maintained in a standby state at a constant low air volume, it returns to the monitoring of the flying shear signal. Otherwise, a fault alarm is issued, and the dust removal fan is manually started to maintain a standby state at a constant air volume after the fault is eliminated.

[0036] Further,

[0037] According to the steel biting signal of the first rough rolling stand, the detection and judgment of whether the dust removal fan is maintained in the standby state with a constant low air volume is established, and the steel biting signal of the side press, the position sensor signal between the side press and the first rough rolling stand, and the steel biting signal of the first rough rolling stand are comprehensively determined.

[0038] When both the side press steel biting signal and the first rough rolling stand steel biting signal are present, and the position sensor signal between the side press and the first rough rolling stand is continuous, then the detection and judgment of whether the dust removal fan is maintained in a standby state with a constant low air volume is established according to the steel biting signal of the first rough rolling stand, otherwise the detection and judgment will not be entered.

[0039] Further,

[0040] When the side press has a steel biting signal and the position sensor signal between the side press and the first rough rolling stand is continuous, but the first rough rolling stand has no steel biting signal, a detection and judgment is established based on the position sensor signal to determine whether the dust removal fan is maintained in a standby state with a constant low air volume.

[0041] Further,

[0042] When the dust removal fan is controlled to enter the variable frequency control state based on the target air volume based on the flying shear signal, the steel biting signal of the first finishing stand, the steel biting signal of the second finishing stand, or the steel biting signal of the third finishing stand, the specific signal is determined according to the frequency conversion speed.

[0043] Further,

[0044] When the signal of the position sensor is normal but the dust removal control machine or the dust removal control unit does not receive the flying shear signal, the dust removal fan is controlled to enter a variable frequency control state based on the target air volume according to the signal of the position sensor combined with the signal of the finishing inlet thermometer.

[0045] Further,

[0046] When the dust removal control machine or the dust removal control unit receives the steel throwing signal of the second to last rack of finishing rolling and / or the steel throwing signal of the last rack, the dust removal fan is controlled to enter a shutdown state.

[0047] Further,

[0048] The target air volume is determined according to the type of rolled steel.

[0049] Further,

[0050] When the dust removal control machine or dust removal control unit has not received the steel throwing signal from the last stand of finishing rolling within the set time,

[0051] or

[0052] If the steel throwing signal of the second to last rack of finishing rolling and the steel throwing signal of the last rack are not received within the set time, the dust removal fan is controlled to enter the shutdown state.

[0053] Further,

[0054] The dust removal fan is driven by a variable frequency motor controlled by a vector inverter.

[0055] Further,

[0056] The vector inverter is established based on speed vector control.

[0057] The present invention provides a hot rolling multi-mode dust removal fan operation control method, which establishes control of the dust removal fan based on actual working conditions and in combination with on-site detection signals, so as to achieve the purpose of energy saving and consumption reduction. Compared with the existing control method of only stopping the fan or operating it at a constant air volume based on whether it is under maintenance, the control strategy and fan operation mode are added to form three operation modes: maintenance operation adaptation control under maintenance conditions, roll changing operation adaptation control under roll changing conditions, and normal rolling operation adaptation control under normal rolling conditions. When in maintenance conditions, the dust removal fan is controlled to stop; when in roll changing conditions, the dust removal fan is controlled to maintain a standby state with a constant low air volume; when in normal rolling conditions, the dust removal fan is controlled to adapt the target air volume and remove dust according to the type of rolled steel. The standby mode under the roller changing condition formed by the above settings can, on the one hand, reduce energy consumption, and on the other hand, avoid the risks such as overcurrent caused by sudden start-stop switching when dust removal is required. It can make a smooth transition to the dust removal condition and ensure the stability of the dust removal operation, which is beneficial to the dust removal quality and product quality.

[0058] The difficulty in the practical transformation of the above technical innovations lies in how to establish accurate tracking and control. The applicant thought of using the existing position sensor signals and thermometers, but these signals may also be lost or inaccurate. The applicant further thought of using the steel biting signals set in each process section, but although these signals are more reliable in theory, they do not rule out the occurrence of empty. At the same time, considering the potential risks such as overcurrent during start-up and shutdown, the normal rolling operation adaptation control under normal rolling conditions is adopted. Before the strip reaches the flying shear station, the fan is allowed to run at a constant low speed. When the strip reaches the flying shear station, the fan is allowed to change frequency to the target air volume. In this way, on the one hand, overcurrent during start-up and shutdown is avoided, and on the other hand, the frequency conversion time is well adapted, so that a good air volume adaptation can be formed when the target dust removal station is reached. Here, the signal credibility problem and the control optimization problem will continue to be involved. In order to solve the signal credibility problem and establish a reliable control based on the on-site detection signal, this technical solution adopts the control based on the flying shear signal and supplemented by the position sensor and thermometer. At the same time, considering the stability of frequency conversion, it is set to run at low speed before dust removal, and continue to switch to low speed after steel throwing. Considering that the frequency conversion transition requires a certain amount of time, the frequency conversion time point is not based on the strip reaching the target rack, but on the strip reaching the flying shear position. At the same time, the change from dust removal state back to standby state is based on the strip reaching the steel throwing position of the last rack of finishing rolling. Control optimization is reflected through the following settings: In order to leave time for inspection and correction of accidents and faults, the start-up of the fan in the technical solution is not based on a certain position before the strip reaches the flying shear, but is set to start the fan and control it in standby state when the strip reaches the dephosphorization position, because this can leave time for subsequent fault inspection and elimination, and the time for fault inspection and elimination is set when the strip reaches the first rack of rough rolling. At the same time, considering that the steel biting signal of the first rough rolling stand may correspond to a strip that is not the target strip, a judgment is established here based on the side press signal and the position sensor signal whether the steel biting of the first rough rolling stand corresponds to the strip. At the same time, the position sensor can also form a replacement when the first rough rolling stand is missing. Correspondingly, the above-mentioned flying shear signal can also be replaced by the position sensor when it is missing; at the same time, since the flying shear signal is not a fixed position point, the first finishing stand, the second finishing stand, or the third finishing stand can also be considered as the frequency conversion time point according to the actual frequency conversion speed. The setting principle and setting purpose are: in a smooth transition manner, when the strip reaches the dust removal target position, the corresponding dust removal air volume is also frequency-converted to the target air volume.

[0059] Some edge-attention optimizations in the above settings, for example, in order to prevent problems with the steel throwing signal of the last stand in the finishing rolling, the steel throwing signal of the F6 stand is combined for control optimization processing; for example, when a fault occurs, there is no steel throwing in the finishing rolling, and the fan needs to be stopped at this time. For example, in the case of roll changing conditions, in order to further reduce energy consumption, attention and tracking of the roll changing time of each roll change is also established, and fan adaptation control based on the specific roll changing time is established.

[0060] In summary, the hot rolling multi-mode dust removal fan operation control method of the present invention is technically set up with all the technical settings centered around reducing energy consumption; with reliable operation as the technical support, it forms a technical solution that takes into account the selection of frequency conversion types, how to control how to reliably establish operation, and the reduction of energy consumption, which is reflected in the multi-dimensional and multi-level optimization settings of each control link; the operating frequency of the frequency converter is always matched with the production conditions, thereby achieving better dust removal and energy-saving effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a control flow diagram of the present invention;

[0062] Figure 2 It is a schematic diagram of the working principle and process of the present invention;

[0063] Figure 3 It is a schematic diagram of the hot rolling process flow in the present invention. DETAILED DESCRIPTION

[0064] Below, a hot rolling multi-mode dust removal fan operation control method of the present invention is further described in detail according to the accompanying drawings and specific implementation methods of the specification.

[0065] In order to better understand this technical solution, its working principle and process are described as follows:

[0066] Before explaining, let me first introduce the surrounding areas involved.

[0067] Hot rolling production line:

[0068] like Figure 3The figure shows a complete hot rolling production line. After the strip is discharged from the heating furnace, it reaches the dephosphorization equipment (the HSB signal mentioned in the text is the dephosphorization signal), removes the iron oxide scale, etc., and then reaches the side press (the SSP signal mentioned in the text is the side press steel biting signal) to enter the rough rolling process section. In the rough rolling process section, the first rough rolling stand R1 and the second rough rolling stand R2 are set in sequence, and then the flying shear (CS mentioned in the text is the flying shear) is set in front, and then it reaches the finishing section. A finishing entrance temperature meter FET is also set at the finishing entrance, and a finishing stand FIE is also set in front of the first finishing stand F1; the finishing section usually has seven stands F1 to F7, and the dust removal section is only for the four stands F4 to F7. In the process section from dephosphorization to steel throwing after the end of finishing rolling, there are position sensors along the way to track the position of each strip, and a temperature meter is also set to perform corresponding temperature tests.

[0069] Communication part:

[0070] Basic communication involves process control machines and basic automation control machines. The basic automation control machine is facing each mechanical execution end and signal acquisition end, and is used to upload each acquired signal to the process control machine for calculation and processing. At the same time, it accepts various control instructions from the process control machine and sends them to the corresponding mechanical execution end.

[0071] The present technical solution involves dust removal control, which can be set up independently of the existing process control machine and the basic automation control machine to form an independent dust removal control machine. Then, by establishing communication with the process control machine, corresponding control can be established according to the existing detection signal. Dust removal control can also be formed by adding functional modules based on the existing basic automation control machine.

[0072] Frequency conversion part:

[0073] Existing frequency conversion technologies include V / F control, vector control and direct torque control. Considering the smoothness and stability of control, as well as low-frequency torque, mechanical characteristics, dynamic performance and other factors, this technical solution adopts vector frequency conversion to establish the control of dust removal air volume, and further selects vector control with speed sensor; the motor selects variable frequency motor to well respond to the low-frequency work required in the technical solution.

[0074] The advantages of the selected vector frequency conversion are as follows:

[0075] 1. Large torque at low frequency. Even when running at 1Hz (or 0.5Hz), it can generate sufficiently large torque and will not produce the magnetic circuit saturation phenomenon that is easily encountered in the U / f control mode.

[0076] 2. Good mechanical properties. In the entire frequency adjustment range, it has relatively hard mechanical properties, and all mechanical properties are basically parallel.

[0077] 3. Good dynamic response. Especially for vector control with speed feedback, the dynamic response time is generally less than 100ms.

[0078] At the same time, in order to give full play to the characteristics of large torque, good mechanical characteristics and good dynamic response of vector control at lower frequencies, and to avoid the micro-defects of soft mechanical characteristics, small system torque and poor state stability at extremely low frequencies, the dust removal standby state of this technical solution is set according to 10% of the rated frequency, that is, the switching input is based on 10% of the rated frequency as the threshold value of vector control input, which truly achieves control that maximizes strengths and avoids weaknesses. Give full play to the advantages of vector control with good adjustability, high stability and low energy consumption.

[0079] Working principle and process, the understanding of the following can be combined with Figure 1 , Figure 2 conduct:

[0080] In order to achieve the purpose of energy saving and consumption reduction, this technical solution first optimizes the original start and stop, based on the maintenance operation adaptive control under the maintenance condition, the roll change operation adaptive control under the roll change condition, and the normal rolling operation adaptive control under the normal rolling condition. Figure 2 Working mode, roll changing mode and maintenance mode.

[0081] This optimization setting has achieved the first level of energy saving and consumption reduction, which is mainly reflected by the newly added roll changing mode. Previously, the dust removal control had only two operating states, either the shutdown state under maintenance conditions or the continuous operation state with constant air volume under non-maintenance conditions. After adding the roll changing mode, energy saving and consumption reduction are achieved by setting the fan in the roll changing mode to maintain a low-speed air volume in the standby state. At the same time, this setting also establishes a good smooth transition step for the corresponding target dust removal control to enter normal rolling after the roll changing is completed, avoiding the potential risks caused by factors such as overcurrent when the motor starts and stops, so that the control can be carried out smoothly. In the roll changing mode, considering that the roll changing time of various rolls is different, further optimization for energy saving and consumption reduction is established for the roll changing time. The control processing is directly stopped for R1 roll changing, because the R1 roll changing time is longer; the standby control processing is performed for R2 roll changing, and the roll changing of the finishing mill is determined according to the specific roll changing time; if the roll changing time exceeds the set time, the shutdown control processing is adopted, otherwise the standby control processing is adopted. Figure 2 As shown, the set duration here is set to about 20 minutes in this technical solution. Under specific working conditions, specific settings can be made according to respective conditions and considerations of various factors.

[0082] The energy-saving and consumption-reducing setting in the second dimension of this technical solution is reflected in the working mode part. At the same time, the difficulty of implementing this technical solution is also here, because the technical concept is as follows: in order to avoid the instability caused by the risk of motor overcurrent during start-stop to the dust removal, and because the frequency conversion requires time transition, first according to the frequency conversion transition time, before the target frequency moment, a low-frequency standby state is formed, and then according to the frequency conversion duration, a smooth transition is made so that when the strip reaches the dust removal destination, the corresponding dust removal air volume is also converted to the target air volume as the setting basis, and the distance corresponding to this time before the target dust removal area is determined. Obviously, this distance is related to the frequency conversion speed, so the specific position needs to be determined according to the specific frequency conversion speed. In the process of putting this technical concept into practice, the first problem encountered is the determination of each target point. This technical solution adopts a solution combining on-site detection signals, but in the actual investment process, control errors caused by the lack or inaccuracy of various signals will continue to occur. In order to further solve these practical problems and make the technical conception practical, the applicant divided the field detection signals into two categories: one is various steel biting signals and steel throwing signals on the hot rolling production line, and the other is various position tracking signals (i.e. HMD signals) and temperature signals of thermometers (i.e. pyrometer signals). A control based on field detection signals was established, which is based on steel biting and steel throwing signals, and supplemented and replaced by HMD signals and pyrometer signals when necessary. Figure 1 As shown, it is specifically reflected in the correct start-up judgment and replacement plan of R1 biting steel, the replacement plan of flying shear signal (the optimization plan based on frequency conversion speed of flying shear signal corresponds to the above purpose of "smooth transition so that when the strip reaches the dust removal target position, the corresponding dust removal air volume is also converted to the target air volume"), and the optimization plan of F7 rack throwing steel.

[0083] The basic control under the working mode established above is:

[0084] When the strip arrives at the dephosphorization station, the process control machine sends a signal to the dust removal control machine or the dust removal control unit. After receiving the signal, the dust removal control unit starts the fan to run at a constant low speed in a standby state. When the strip arrives at the flying shear position, the frequency conversion is started again according to the arrival signal. At this time, the fan is driven by the variable frequency motor to change the frequency from the standby state to the target air volume. According to the preset, when the strip arrives at the fourth rack of the finishing rolling, the frequency conversion from low frequency to target frequency is almost completed synchronously. Then, the dust removal of the target process section is carried out according to the current target frequency, until the last rack of the finishing rolling sends a steel throwing signal, and then the fan is controlled to change the frequency from the target frequency operation state to a constant low speed operation in a standby state, waiting for the next piece of strip. The specific value of the target air volume here is determined according to the specific strip type and is determined by the process requirements.

[0085] In the above basic control, in order to ensure that the fan is started in standby mode when the strip reaches the flying shear position, a control based on the detection of R1 steel biting position is established to determine whether it is started normally. Specifically:

[0086] When the dust removal control machine receives the steel biting signal of the first rough rolling stand sent by the process control machine, it determines whether it is started normally. When the detection result is a normal start, no processing is performed and the control continues according to the set control. When it is detected that it is not started normally, it is immediately checked and processed, and after elimination, it is manually controlled to start through the set dry contact to restore it to the normal standby operation state. Due to the continuity of the front and rear strips, there may be a situation where the steel biting signal of the first rough rolling stand may not correspond to the target strip. Therefore, in order to avoid the control confusion caused by this problem, a correct start judgment is established here. Specifically: the steel biting signal of the side press, the position sensor signal between the side press and the first rough rolling stand, and the steel biting signal of the first rough rolling stand are combined to determine. When both the side press steel biting signal and the rough rolling first frame steel biting signal are present, and the position sensor signal between the side press and the rough rolling first frame is continuous, then the detection and judgment of whether the dust removal fan is maintained in a standby state with a constant low air volume is established according to the steel biting signal of the rough rolling first frame, otherwise the detection and judgment is not entered. At the same time, a replacement scheme can also be formed here when the steel biting signal is missing, specifically: when the side press has a steel biting signal and the position sensor signal between the side press and the rough rolling first frame is continuous, but the rough rolling first frame does not have a steel biting signal, then the detection and judgment of whether the dust removal fan is maintained in a standby state with a constant low air volume is established according to the position sensor signal.

[0087] According to the various optimizations established in each link, the final optimized control logic is:

[0088] First, the control mode is switched according to the current working conditions. When the fan is in the maintenance mode, the fan is controlled to be in the shutdown state.

[0089] When the current mode is roll changing, the fans are first controlled to run at a constant low speed in a standby state, and then further optimized control processing is performed according to the specific roll changing time. When the current roll changing is R1 roll changing, the fans are directly controlled to stop. When the current roll changing is R2 roll changing, the fans are directly controlled to run in a standby state. When the current roll changing is a finishing mill roll changing, specific control processing is performed in combination with the specific roll changing time. When the roll changing time exceeds the set threshold, the fans are controlled to stop. Otherwise, the fans are controlled to run in a standby state.

[0090] When the current mode is normal rolling operation, the fan is first started according to the dephosphorization signal, and then at the first rough rolling stand, a judgment is made on whether the start-up is successful according to the steel biting signal of the first rough rolling stand. When the start-up is successful, control is continued. Otherwise, manual troubleshooting and manual direct start-up are performed to return the control to normal main control. Here, there will be a judgment process for establishing a correct correspondence between the strip steel and the signal by combining the side press steel biting signal and the position sensor signal, as well as a replacement scheme when the steel biting signal is missing, that is, when the side press steel biting signal and the steel biting signal of the first rough rolling stand are both present, and the position sensor signal between the side press and the first rough rolling stand is continuous, then the detection and judgment of whether the dust removal fan is maintained in a standby state with a constant low air volume is established according to the steel biting signal of the first rough rolling stand, otherwise the detection and judgment will not be entered; when the side press has a steel biting signal and the position sensor signal between the side press and the first rough rolling stand is continuous, but the first rough rolling stand has no steel biting signal, then the detection and judgment of whether the dust removal fan is maintained in a standby state with a constant low air volume is established according to the position sensor signal. When the strip steel runs to the flying shear position, the frequency conversion action is started according to the CS on signal to make the air volume transition from the previous low air volume to the target air volume. When the CS signal is missing, a replacement scheme can be formed according to the second type of signal established, that is, when the signal of the position sensor is normal but the dust removal control machine or dust removal control unit does not receive the flying shear signal, the dust removal fan is controlled to enter the variable frequency control state based on the target air volume according to the signal of the position sensor combined with the thermometer signal at the finishing entrance. At the same time, the frequency conversion time point established according to the flying shear signal is not unique, because the setting basis for establishing the frequency conversion according to the flying shear signal is to see whether the current frequency conversion speed can make the strip at the flying shear position run to the F3 frame, and whether the corresponding air volume just reaches the target air volume, that is, the internal setting basis is to determine the frequency conversion time and frequency conversion position according to the current frequency conversion speed, so according to the specific frequency conversion speed, this position can be changed, but considering the control reliability, the thermometer signal at the finishing entrance, the steel biting signal of the first finishing frame, the steel biting signal of the second finishing frame, and the steel biting signal of the third finishing frame become alternative signals to form an adaptation with the specific frequency conversion speed. Finally, when the last stand of the finishing rolling mill sends a steel throwing signal, considering the cyclic nature of rolling, the fan is controlled to switch to a low-speed standby state according to the steel throwing signal. Then, when the second and subsequent strips undergo dephosphorization, it is not necessary to establish a start judgment based on the dephosphorization signal, but directly determine whether it is started normally based on the R1 signal. Similarly, in order to ensure the stability of operation and respond to emergencies, an optimization plan and a control plan for responding to faults are also established at the F7 steel throwing.In order to prevent problems with the steel-throwing signal of the last rack of finishing rolling, the steel-throwing signal of the F6 rack is combined to form an optimized control to control the dust removal fan to enter a shutdown state when the dust removal control machine or the dust removal control unit receives the steel-throwing signal of the second-to-last rack of finishing rolling and / or the steel-throwing signal of the last rack. At the same time, when the dust removal control machine or the dust removal control unit has not received the steel-throwing signal of the last rack of finishing rolling within the set time, or has not received the steel-throwing signal of the second-to-last rack of finishing rolling and the steel-throwing signal of the last rack within the set time, the dust removal fan is controlled to enter a shutdown state.

[0091] In order to quickly understand the above explanation, a brief summary of the above explanation is now formed as follows:

[0092] The control mode is automatically adapted according to the different production conditions of the main rolling line, and the inverter is controlled in real time according to different frequencies to achieve multi-mode control: maintenance mode, roll change mode, and working mode. At the same time, the dust removal system will automatically match the fan status according to the rolling line equipment status, that is, shutdown status, standby status, vector control status, and abnormal status. The inverter operating frequency and production conditions are always matched to each other, so as to achieve the best dust removal and energy saving effect;

[0093] The fan status and corresponding fan frequency can be preset in the dust removal system. Taking the production line involved in this technical solution as an example, the specific correspondence between the fan status and the operating frequency is as follows:

[0094]

[0095]

[0096] That is, standby: less than 10%; vector control: 10%-100%.

[0097] Dust removal fan mode selection

[0098] In order to realize the dust removal system in different working conditions of the rolling line, the dust removal system can manually or automatically select the corresponding control mode, namely the maintenance mode, roll change mode, and working mode. The dust removal system is operated in advance before the rolling line starts. The L1 and L2 systems need to optimize the relevant tracking and calculations and set the necessary operating data for the dust removal system.

[0099] Combined with the different states of the current rolling line, namely maintenance mode, roll changing mode, working mode and other states.

[0100] The dust removal system PLC returns to the basic automation L1 to set multiple digital DI contacts, that is,

[0101] (1) Dust removal fan control mode automatic / manual;

[0102] (2) Dust removal control system operating status: running / stop;

[0103] (3) Dust removal fan body, transmission device and PLC status equipment: normal / fault;

[0104] (4) Frequency conversion control and vector control of dust removal fan:

[0105] In order to realize the 1880 dust removal system in different working conditions of the rolling line, namely maintenance mode, roll change mode, and working mode, the following table shows the HMD and pyrometer signal status currently involved in the hot rolling line:

[0106]

[0107] The above table can be used to calculate whether the equipment in the rough rolling or finishing rolling area is currently in maintenance mode, roll changing mode, working mode, etc.

[0108] Maintenance mode

[0109] The status of the dust removal equipment is displayed in combination with the HMI (dust removal) screen of the finishing main rolling line (red for stop, green for operation, and yellow for fault). At the same time, the above status is displayed on the HMI screen of the finishing oil depot, and the maintenance mode button is selected under the condition of scheduled maintenance of the entire plant or long-term shutdown, and the dust removal fan enters the shutdown state.

[0110] Roller changing mode

[0111] The L2 server sends the roller changing status information to the dust removal system, guiding the dust removal system to enter the roller changing mode.

[0112] When the dust removal system receives the roller change message sent by the server, a ROLL_STATUS event is generated and corresponding processing is performed. ROLL_STATUS event definition:

[0113]

[0114] FmRollchangeLongTime is issued by the dust removal setting program, and other roll change status is issued by the L2 receiving program.

[0115] Depending on the roller changing time, the dust removal fan adopts two states: standby and shutdown. Taking the 1880 production line as an example, the roller changing time exceeding 20 minutes adopts the shutdown state.

[0116] When changing rolls on the rolling line, the status of the L2 fan is as follows:

[0117] When R1 changes rollers, the fan shutdown status is sent;

[0118] When R2 changes rollers, the fan standby state is sent;

[0119] When FM changes rollers, the fan standby state is sent;

[0120] When FM roll changing continues for 20 minutes without rolling steel, the sending fan enters the shutdown state.

[0121] Working Mode

[0122] When the L2 server sends the working status information to the dust removal system, the fan enters the standby state. When the strip reaches R1, that is, in the R1ON state, the fan status is checked. If the fan still does not start, an abnormal alarm message is sent to L1; when the strip reaches the flying shear, that is, in the CS ON state, the fan enters the vector control state. When the strip is thrown, that is, in the F7 OFF state, the fan enters the standby state.

[0123] To prevent abnormal conditions such as scrap steel from causing signal loss, if L1 does not receive the F7 OFF signal within 120 seconds after receiving CS ON, it will send an abnormal alarm and switch to standby mode.

Claims

1. A hot rolling multi-mode dust removal fan operation control method, characterized in that: From the dephosphorization to the finishing and polishing process of the hot rolling production line, the dust removal fan operation mode is established according to the actual working conditions in combination with the on-site detection signals; The dust removal fan operation mode is established according to the actual working conditions, specifically: Establish maintenance operation adaptation control, roll changing operation adaptation control and normal rolling operation adaptation control of the dust removal fan under maintenance conditions, roll changing conditions and normal rolling conditions respectively.

2. A hot rolling multi-mode dust removal fan operation control method according to claim 1, characterized in that: A dust removal control machine that is independent of the process control machine and the basic automation control machine and is used to establish the maintenance operation adaptation control, roll change operation adaptation control and normal rolling operation adaptation control of the dust removal fan. The dust removal control machine can communicate with the process control machine; or A dust removal control unit is added to the basic automation control machine, and the added dust removal control unit establishes adaptation control for the maintenance operation of the dust removal fan, the roll changing operation adaptation control and the normal rolling operation adaptation control.

3. A hot rolling multi-mode dust removal fan operation control method according to claim 2, characterized in that: When in maintenance condition, the dust removal fan is stopped by the dust removal control machine or dust removal control unit; When in the roller changing condition, the dust removal control machine or dust removal control unit controls the dust removal fan status accordingly according to the current roller changing time; When in normal rolling conditions, the dust removal fan or dust removal control unit performs corresponding dust removal fan status control according to the on-site detection signal.

4. A hot rolling multi-mode dust removal fan operation control method according to claim 3, characterized in that: When in the roller changing condition, the dust removal control machine or dust removal control unit controls the dust removal fan status accordingly according to the current roller changing time, specifically: When the roller replacement time exceeds the set threshold, the dust removal control machine or the dust removal control unit controls the dust removal fan to stop; Otherwise, the dust removal fan is put into standby mode by the dust removal control machine or the dust removal control unit.

5. A hot rolling multi-mode dust removal fan operation control method according to claim 4, characterized in that: When the roll is changed for the first stand of rough rolling, the judgment and control are directly carried out according to the roll change exceeding the set threshold; When changing the rolls of the second stand of rough rolling, the judgment and control are directly carried out according to the fact that the roll change does not exceed the set threshold; When the rollers of the finishing mill are changed, the roller changing time is counted. When the roller changing time exceeds the set threshold, the dust removal control machine or the dust removal control unit controls the dust removal fan to stop; otherwise, the dust removal control machine or the dust removal control unit controls the dust removal fan to standby.

6. A hot rolling multi-mode dust removal fan operation control method according to claim 3, characterized in that: When in normal rolling conditions, the dust removal fan or dust removal control unit performs corresponding dust removal fan status control according to the on-site detection signal, specifically: When the dust removal control machine or the dust removal control unit receives the dephosphorization signal of the first strip steel, the dust removal fan is controlled to maintain a standby state with a constant low air volume; When the dust removal control machine or the dust removal control unit receives the flying shear signal or the steel biting signal of the first finishing rolling stand or the steel biting signal of the second finishing rolling stand or the steel biting signal of the third finishing rolling stand, the dust removal fan is controlled to enter the variable frequency control state based on the target air volume based on one of the signals; When the dust removal control machine or the dust removal control unit receives the steel throwing signal of the last stand of finishing rolling, the dust removal fan is controlled to enter the standby state.

7. A hot rolling multi-mode dust removal fan operation control method according to claim 6, characterized in that: When the dust removal control machine or the dust removal control unit receives the phosphorus removal signal, it controls the dust removal fan to maintain a standby state at a constant low air volume. It also establishes a detection and judgment on whether the dust removal fan is maintained in a standby state at a constant low air volume based on the steel biting signal of the first rough rolling stand. When the detection result shows that the dust removal fan is maintained in a standby state at a constant low air volume, it returns to the monitoring of the flying shear signal. Otherwise, a fault alarm is issued, and the dust removal fan is manually started to maintain a standby state at a constant air volume after the fault is eliminated.

8. A hot rolling multi-mode dust removal fan operation control method according to claim 7, characterized in that: According to the steel biting signal of the first rough rolling stand, the detection and judgment of whether the dust removal fan is maintained in the standby state with a constant low air volume is established, and the steel biting signal of the side press, the position sensor signal between the side press and the first rough rolling stand, and the steel biting signal of the first rough rolling stand are comprehensively determined. When both the side press steel biting signal and the first rough rolling stand steel biting signal are present, and the position sensor signal between the side press and the first rough rolling stand is continuous, then the detection and judgment of whether the dust removal fan is maintained in a standby state with a constant low air volume is established according to the steel biting signal of the first rough rolling stand, otherwise the detection and judgment will not be entered.

9. A hot rolling multi-mode dust removal fan operation control method according to claim 8, characterized in that: When the side press has a steel biting signal and the position sensor signal between the side press and the first rough rolling stand is continuous, but the first rough rolling stand has no steel biting signal, a detection and judgment is established based on the position sensor signal to determine whether the dust removal fan is maintained in a standby state with a constant low air volume.

10. A hot rolling multi-mode dust removal fan operation control method according to claim 6, characterized in that: When the dust removal fan is controlled to enter the variable frequency control state based on the target air volume based on the flying shear signal, the steel biting signal of the first finishing stand, the steel biting signal of the second finishing stand, or the steel biting signal of the third finishing stand, the specific signal is determined according to the frequency conversion speed.

11. A hot rolling multi-mode dust removal fan operation control method according to claim 6, characterized in that: When the signal of the position sensor is normal but the dust removal control machine or the dust removal control unit does not receive the flying shear signal, the dust removal fan is controlled to enter a variable frequency control state based on the target air volume according to the signal of the position sensor combined with the signal of the finishing inlet thermometer.

12. A hot rolling multi-mode dust removal fan operation control method according to claim 6, characterized in that: When the dust removal control machine or the dust removal control unit receives the steel throwing signal of the second to last rack of finishing rolling and / or the steel throwing signal of the last rack, the dust removal fan is controlled to enter a shutdown state.

13. A hot rolling multi-mode dust removal fan operation control method according to claim 6, characterized in that: The target air volume is determined according to the type of rolled steel.

14. A hot rolling multi-mode dust removal fan operation control method according to claim 6 or 12, characterized in that: When the dust removal control machine or dust removal control unit has not received the steel throwing signal from the last stand of finishing rolling within the set time, or If the steel throwing signal of the second to last rack of finishing rolling and the steel throwing signal of the last rack are not received within the set time, the dust removal fan is controlled to enter the shutdown state.

15. A hot rolling multi-mode dust removal fan operation control method according to claim 1 or 6, characterized in that: The dust removal fan is driven by a variable frequency motor controlled by a vector inverter.

16. A hot rolling multi-mode dust removal fan operation control method according to claim 15, characterized in that: The vector inverter is established based on speed vector control.

Images