A control device and method for preventing the cable of a hot rolling roll changing trolley from being broken

Abstract

A control device and method for preventing the cable of a hot rolling roll changing trolley from being broken belongs to the technical field of hot rolling mill equipment and methods, and is used to prevent the power cable of the roll changing trolley from being broken. The technical solution is: the proximity switch of the invention is installed on both sides of the cable drum, and the proximity switch can monitor the rotation of the cable drum during the operation of the roll changing trolley. The proximity switch transmits the monitoring signal to the programmable controller (PLC), and the programmable controller (PLC) judges the rotation of the cable drum. When the monitoring signal shows that the cable drum stops rotating, it promptly issues an instruction to stop the operation of the roll changing trolley to prevent the power cable of the trolley from being broken due to mechanical obstruction of the drum. The invention has an ingenious design concept and a simple control process. It is the first of its kind in hot rolling control technology, filling the gap in the field of control technology for preventing the power cable of the roll changing trolley from being broken, completely eliminating the accident of the cable breaking of the roll changing trolley, and greatly improving production efficiency.

Description

Technical Field

[0001] The invention relates to a control device and method for preventing a power cable of a roll-changing trolley from being broken during roll-changing operations of a hot rolling finishing mill and a roughing mill, and belongs to the technical field of hot rolling mill equipment and methods. Background Art

[0002] During the high-speed rolling process, the working rolls of the hot rolling production line are greatly worn. After each rolling plan is completed, the working rolls need to be replaced, and the working rolls are replaced more than 5 times a day. The high-load and fast-paced production of the hot rolling line requires the roll replacement process to be completed efficiently, quickly and automatically. Therefore, reducing the failure rate of the roll replacement trolley is of great significance to the smooth production of the hot rolling production line. Since the hot rolling was put into production, the failure of the roll replacement system has mainly focused on the cable reel of the roll replacement trolley. During the roll replacement process, the cable reel has stopped due to mechanical blocking many times, while the roll replacement trolley continues to move forward, causing the cable to break. It takes 2 hours to replace the cable of the roll replacement trolley, which seriously affects the normal production of hot rolling and causes great economic losses. At present, there is a lack of control technology to prevent the power cable of the roll replacement trolley from breaking in the hot rolling automatic control system at home and abroad, making the breaking of the power cable a common and high-incidence accident in the roll replacement process of the hot rolling production line. It is urgent to develop a control device and method to prevent the cable of the hot rolling roll replacement trolley from breaking to ensure the normal production. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a control device and method for preventing the cable of a hot rolling roll changing trolley from being pulled apart. This device and method can prevent cable pulling-off accidents caused by mechanical obstruction of the cable reel during the movement of the roll changing trolley, and can effectively solve the technical problem of high incidence of cable pulling-off failures in the roll changing system of the hot rolling production line, filling the technical gap in the field of cable pulling-off prevention control in the roll changing system of the hot rolling production line.

[0004] The technical solution to solve the above technical problems is:

[0005] A control device for preventing the cable of a hot rolling roll changing trolley from being pulled off comprises a proximity switch and a programmable controller (PLC). Two proximity switches are respectively installed on both sides of the cable drum of the roll changing trolley. The proximity switches are connected to a counter module of the programmable controller (PLC). The signal output end of the programmable controller (PLC) is respectively connected to a control end and an alarm of a roll changing trolley driving device.

[0006] The above control device for preventing the cable of the hot rolling roll changing trolley from being pulled apart, the two proximity switches are installed at opposite sides of the center of the cable drum of the roll changing trolley, and the distance between the two proximity switches and the center of the cable drum of the roll changing trolley is 350 mm respectively.

[0007] A control method for preventing the cable of a hot rolling roll changing trolley from being broken using the above control device is carried out by the following steps:

[0008] a. There are multiple rotating shafts on the circumference of the cable drum, which are radially distributed with the center of the cable drum as the center. The spacing between adjacent rotating shafts is equal. During the movement of the roller-changing trolley, multiple rotating shafts continuously pass by the proximity switch, triggering the proximity switch, which continuously transmits the trigger signal to the signal input terminal of the programmable controller (PLC);

[0009] b. In the programmable logic controller (PLC), the counter module counts the number of shaft rotations detected by the proximity switch;

[0010] c. During the operation of the roller-changing trolley, the roller-changing trolley has different speeds at different stages and specific positions, and the corresponding shafts also have different revolutions. In the programmable controller (PLC), different delay times are set according to the actual operating speed and specific positions of the roller-changing trolley, and different delay times correspond to the corresponding revolutions of the shaft;

[0011] d. The programmable logic controller (PLC) monitors the number of detections of the rotating shaft. When it detects that the number of rotations of the rotating shaft is significantly reduced or no longer increases compared with the set rotation value within the corresponding delay time, the programmable logic controller (PLC) determines that a mechanical jam has occurred in the cable reel and automatically issues a command to stop the roller-changing trolley to prevent the cable from breaking.

[0012] The above-mentioned control method for preventing the cable of the hot rolling roll changing trolley from being pulled apart is that the roll changing trolley has bidirectional movement on the roll changing roller table, and there are high-speed operation stages and low-speed operation stages in the movement in different directions. When the roll changing trolley is running at high speed and low speed, the running linear speed of the cable reel is consistent with the running speed of the roll changing trolley, and the time interval at which the proximity switch detects the cable reel rotating shaft in the high-speed operation stage of the roll changing trolley is shorter than the time interval at which the proximity switch detects the cable reel rotating shaft in the low-speed operation stage of the roll changing trolley, and the corresponding programmable controller (PLC) sets different delay times.

[0013] The above-mentioned control method for preventing the cable of the hot rolling roll changing trolley from being pulled apart, the roll changing trolley has a reversing operation stage and a cable drum reversing area on the roll changing roller table, during the reversing operation stage and the cable drum reversing area, the rotation speed of the cable drum changes, the rotation interval of the rotating shaft detected by the proximity switch increases, and the corresponding programmable controller (PLC) sets different delay times.

[0014] The above-mentioned control method for preventing the cable of the hot rolling roll changing trolley from being pulled apart is as follows: when the roll changing trolley is in the high-speed operation stage, the fault alarm time interval of the programmable controller (PLC) counter is set to 16 seconds, and when the roll changing trolley is in the low-speed operation stage, the fault alarm time interval of the programmable controller (PLC) counter is set to 4 seconds; in the cable reel reeling area, the fault alarm time interval of the programmable controller (PLC) counter is set to 24 seconds.

[0015] The beneficial effects of the present invention are:

[0016] The proximity switch of the present invention is installed on both sides of the cable drum. The proximity switch can effectively monitor the rotation of the cable drum during the operation of the roller-changing trolley. The proximity switch transmits the monitoring signal to the programmable controller (PLC). The programmable controller (PLC) judges the rotation of the cable drum and issues a command to stop the operation of the roller-changing trolley in time when the monitoring signal shows that the cable drum stops rotating, so as to prevent the phenomenon that the power cable of the trolley is broken due to the mechanical obstruction of the drum. The present invention realizes effective monitoring of the rotation state of the cable drum, and the control method has high accuracy in operation.

[0017] The present invention is the first of its kind in hot rolling control technology, filling the gap in the field of control technology for preventing the power cable of the roll-changing trolley from breaking, and effectively solving the technical problem of frequent cable breaking failures in the roll-changing system of the hot rolling production line. The present invention has an ingenious design concept, a simple control process, and is easy to implement. After nearly two years of practice in the hot rolling line, it has been proven to have a good effect, completely eliminating the cable breaking accident of the roll-changing trolley, greatly improving production efficiency, and has a high promotion value in the same type of production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a control device for preventing the cable of a hot rolling roll changing trolley from being pulled off according to the present invention;

[0019] Figure 2 This is a schematic diagram of the roller changing trolley traveling on the roller table.

[0020] The markings in the figure are as follows: roller changing roller table 1, roller table gear 2, rotating pulley 3, drum shaft 4, proximity switch 5, cable drum 6, trolley power cable 7. DETAILED DESCRIPTION

[0021] The control device for preventing the cable of the hot rolling roll changing trolley from being pulled off of the present invention comprises a proximity switch 5 and a programmable logic controller (PLC).

[0022] Figure 1It is shown that two proximity switches 5 are respectively installed on both sides of the cable drum 6 of the roll-changing trolley, the proximity switches 5 are connected to the counter module of the programmable controller (PLC), and the signal output end of the programmable controller (PLC) is respectively connected to the control end and the alarm of the roll-changing trolley drive device.

[0023] Figure 1 It is shown that the installation positions of the two proximity switches 5 are opposite to each other on both sides of the center of the cable drum 6 of the roller changing trolley, and the distances between the two proximity switches 5 and the center of the cable drum 6 of the roller changing trolley are 350 mm respectively.

[0024] The present invention installs a proximity switch 5 on a baffle plate of a cable drum 6 of a roll-changing trolley, one of which is installed on each side of the cable drum 6, to detect the rotation of the cable drum 6 of the roll-changing trolley, and accumulates and calculates the number of times the proximity switch 5 detects the rotating shaft 4 of the cable drum 6 in each scanning cycle of a programmable controller (PLC). When the output result of the accumulator CTU in a certain scanning cycle is equal to the output result before a specific time, that is, the proximity switch 5 continuously fails to detect the rotating shaft 4, the programmable controller (PLC) determines that a mechanical blocking fault occurs in the cable drum 6, and automatically sends a roll-changing trolley fault signal to the roll-changing control system, and the roll-changing trolley stops running, thereby preventing the trolley power cable 7 from being pulled apart due to the mechanical blocking of the drum.

[0025] A proximity switch 5 of an embodiment of the present invention is installed on a baffle plate 350 mm away from the center of a cable drum 6. There are 12 rotating shafts 4 on the cable drum 6, and the angle between two rotating shafts 4 is 30 degrees. During the operation of the trolley, the proximity switch 5 detects the 12 rotating shafts 4. Each time the proximity switch 5 detects a rotating shaft 4, the output result of the counter is increased by 1, and the programmable controller (PLC) scans the output result in each scanning cycle.

[0026] Figure 2 It is a schematic diagram of the roller changing trolley in the running state on the roller changing roller table 1.

[0027] During operation, the roll-changing roller table 1 is divided into 13 positions from E1 to E13. The roll-changing trolley switches speed and running direction at different positions, and the programmable controller (PLC) controls the rolling mill to perform corresponding actions. When the roll-changing trolley moves forward from E6 to E8, it first runs to E8, lifts the trolley hook to disengage the new working roll, and then runs backward to E6. The transverse platform moves transversely in the rough rolling direction. The roll-changing trolley runs forward without new working rolls until the finishing mill extracts the old working rolls. In this process, the running direction is switched between E6 and E8. When the roll-changing trolley runs in the direction of the initial position E1, it also switches the running direction between E6 and E8. During the entire operation of the roll-changing trolley, there are three position control points at E4, E9, and E10. At this position, the roll-changing trolley switches from high speed to low speed, and there is a conversion of the running speed at this position. In the present invention, the high speed is 0.4m / s and the low speed is 0.08m / s.

[0028] Figure 2 The display shows that the roller changing trolley is moving on roller changing roller table 1 as follows:

[0029] Firstly, during the operation of the roller changing trolley, the running linear speed of the cable reel 6 is matched with the traveling speed of the roller changing trolley. The rotational angular velocity of the cable reel 6 can be calculated in real time according to the formula of angular velocity and linear speed: V=wr and the radius of the circle where the outer and inner circles of the cable are located; the cable reel 6 is on the roller changing roller table 1 from the initial position E1 to the position 17000mm away from E1, and the cable is rolled from the inner diameter of the cable reel 6 onto the cable reel 6 from the roller changing roller table 3 in a clockwise direction as the roller changing trolley runs; from the position of 17000mm to the end position of 30823mm of the roller changing roller table 1, the cable is laid out in a counterclockwise direction from the outer diameter of the cable reel 3 into the cable trough of the roller changing roller table 3. During this process, the running line speed of the cable drum 6 is consistent with that of the roller-changing trolley. Due to the change in the cable reel diameter, the angular velocity of the cable drum changes in real time: the high-speed running speed of the roller-changing trolley is 0.4m / s, and the low-speed running speed is 0.08m / s. The inner diameter of the cable drum 6 is 630mm and the outer diameter is 1400mm. Based on this calculation, it can be obtained that when the roller-changing trolley is running at high speed, the proximity switch 6 detects the shaft 4 once in 0.4-0.9 seconds, and detects the shaft 4 once in 2-4.5 seconds when running at low speed. When the trolley is running at high speed, the fault alarm time interval of the programmable controller (PLC) counter is set to 16 seconds, and the fault alarm time is 4 seconds when running at low speed.

[0030] Secondly, there are two special positions of the roll-changing trolley during operation. The first is the E6-E8 position of the roll-changing roller table 1. When the roll-changing trolley pushes the new working roll forward into the finishing mill, it first runs to the E8 position of the roll-changing roller table 1. At this position, the roll-changing trolley is unhooked and lifted to detach from the working roll, and then runs backward to the E6 position. During this process, the running direction of the roll-changing trolley changes. At this time, the programmable controller (PLC) detects one of the shafts 4. In the next scanning cycle of the programmable controller (PLC), the next shaft 4 is about to rotate to the detection position of the proximity switch 5, but the rotation direction of the cable drum 6 changes from clockwise to counterclockwise. In this case, the proximity switch 5 detects once that the angle of the shaft 4 changes from 30 degrees to 60 degrees, and the detection cycle is doubled. At this time, the fault scanning time needs to be designed separately. Add the E6 and E8 position trolley reversing judgment and fault alarm delay control functions in the automatic control system.

[0031] Another special position is the cable drum reel direction change position, which is located at 17000mm of the roller changing roller 1. In the 0-17000mm area of ​​the roller changing roller 1, the cable drum 6 rotates in a clockwise direction from the initial position E0 of the roller changing roller 1, and the cable is rolled from the cable trough of the roller changing roller 1 to the cable drum 6. When it runs to the 17000mm position, all the cables are rolled onto the cable drum 6. In the 17000-30823mm area, the cable drum 6 rotates counterclockwise, and the cable is laid flat in the cable trough as the roller changing trolley runs. Therefore, the 17000mm position is the cable drum 6 rotation direction change position, and there is also the problem of extended detection time of the two shafts 4 at this position. In the cable drum reel direction change area, the fault alarm time is set to 24 seconds, and the counter reset control function is designed to avoid the system from producing false alarms when the count value reaches the upper limit of the count and no longer accumulates.

[0032] Finally, after receiving the cable drum 6 fault alarm signal, the programmable controller (PLC) sends a roll-changing trolley fault signal to the roll-changing control system, and the roll-changing trolley stops running to prevent the trolley power cable 7 from being broken due to mechanical obstruction of the drum.

[0033] In the present invention, the counting range of the programmable controller (PLC) counter CTU is 0-37273. In order to prevent the count value from reaching the maximum value of 37273 during the roll changing process and the detection value from no longer accumulating to cause a false alarm, the method of the present invention has the function of timely resetting the count value. By using the closed point of the running signal of the frame roll changing trolley, that is, when the trolley stops running, the system automatically assigns the count value to 0, and CTU restarts counting from 0. This method effectively shields the false alarm caused by the counter reaching the upper limit setting value.

[0034] The present invention effectively prevents the occurrence of accidents in which the power cable 7 of the trolley is pulled off due to the failure of the cable drum 6 to rotate by detecting the actual rotation of the rotating shaft 4 and setting different control methods for different speeds and positions of the roller-changing trolley. At the same time, this method effectively shields the occurrence of false alarms of the system. After more than two years of practice in the hot rolling mill, good application results have been achieved. The method has stable control, significantly reduced the failure rate of the roller-changing trolley, increased the daily operation rate of the production line, and further reduced the cost of spare parts such as cables. This method fills the technical gap in the field of preventing the power cable from being pulled off in the roller-changing trolley, and has a high promotion value in the same type of production line.

Claims

1. A control device to prevent the cable of a hot rolling roll changing trolley from being pulled off, characterized in that: It comprises a proximity switch (5) and a programmable controller (PLC), wherein the two proximity switches (5) are respectively installed on both sides of the cable drum (6) of the roller-changing trolley, the proximity switches (5) are connected to a counter module of the programmable controller (PLC), and the signal output end of the programmable controller (PLC) is respectively connected to a control end of a roller-changing trolley driving device and an alarm; The control method for preventing the cable of the hot rolling roll changing trolley from being pulled off by the above control device is carried out by the following steps: a. A plurality of rotating shafts (4) are arranged on the circumference of the cable drum (6), the plurality of rotating shafts (4) are radially distributed with the center of the cable drum (6) as the center, and the spacing between adjacent rotating shafts (4) is equal. During the movement of the roller-changing trolley, the plurality of rotating shafts (4) continuously pass the proximity switch (5), triggering the proximity switch (5), and the proximity switch (5) continuously transmits the trigger signal to the signal input terminal of the programmable controller (PLC); b. In a programmable controller (PLC), a counter module counts the number of times the shaft (4) is detected by the proximity switch (5); c. During the operation of the roller changing trolley, the roller changing trolley has different speeds at different stages and specific positions, and the corresponding rotating shaft (4) also has different rotation speeds. In the programmable controller (PLC), different delay times are set according to the actual operating speed of the roller changing trolley and the specific position, and the different delay times correspond to the corresponding rotation speeds of the rotating shaft (4); d. The programmable controller (PLC) monitors the number of detections of the rotating shaft (4). When it is detected that the number of rotations of the rotating shaft (4) is significantly lower than the set rotation value during the corresponding delay time or no longer increases, the programmable controller (PLC) determines that a mechanical jam has occurred in the cable reel (6) and automatically issues a command to stop the roller-changing trolley to prevent the cable from being broken; The roller changing trolley moves in both directions on the roller changing roller table (1), and has a high-speed operation stage and a low-speed operation stage in the movement in different directions. When the roller changing trolley is running at high speed or low speed, the running line speed of the cable drum (6) is consistent with the running speed of the roller changing trolley. The time interval at which the proximity switch (5) detects the rotating shaft (4) of the cable drum (6) in the high-speed operation stage of the roller changing trolley is shorter than the time interval at which the proximity switch (5) detects the rotating shaft (4) of the cable drum (6) in the low-speed operation stage of the roller changing trolley. The corresponding programmable controller (PLC) sets different delay times.

2. The control device for preventing the cable of the hot rolling roll changing trolley from being pulled off according to claim 1 is characterized in that: The two proximity switches (5) are installed at opposite sides of the center of the cable drum (6) of the roller-changing trolley, and the distance between the two proximity switches (5) and the center of the cable drum (6) of the roller-changing trolley is 350 mm respectively.

3. The control device for preventing the cable of the hot rolling roll changing trolley from being pulled off according to claim 2 is characterized in that: The roller-changing trolley has a reversing operation stage and a cable drum reversing area on the roller-changing roller table (1). During the reversing operation stage and the cable drum reversing area, the rotation speed of the cable drum (6) changes, the rotation interval of the rotating shaft (4) detected by the proximity switch (5) increases, and the corresponding programmable controller (PLC) sets different delay times.

4. The control device for preventing the cable of the hot rolling roll changing trolley from being pulled off according to claim 3 is characterized in that: When the roller changing trolley is in the high-speed operation stage, the fault alarm time interval of the programmable controller (PLC) counter is set to 16 seconds, when the roller changing trolley is in the low-speed operation stage, the fault alarm time interval of the programmable controller (PLC) counter is set to 4 seconds, and in the cable reel reeling area, the fault alarm time interval of the programmable controller (PLC) counter is set to 24 seconds.

Images