A control method and system for an out-of-furnace heat preservation roller table

Abstract

The present invention discloses a control method and system for an out-of-furnace heat preservation roller table. The method includes: arranging a first heat detector beside the starting roller of the heat preservation roller table and a second heat detector beside the end roller of the heat preservation roller table. The first heat detector is close to the heating furnace, and the second heat detector is close to the rolling mill; when the first heat detector detects a billet, switching the roller speed in the heating furnace to keep it synchronized with the speed of the heat preservation roller table; when the current billet enters the rolling mill along the heat preservation roller table and receives a signal of steel biting, switching the speed of the heat preservation roller table to keep it synchronized with the rolling mill speed; when the second heat detector detects the arrival of the falling edge of the signal, increasing the speed of the heat preservation roller table to make the next billet move forward quickly along the heat preservation roller table until the arrival of the next steel biting signal. By specifically adjusting the speed of the heat preservation roller table, the present invention avoids roller wear and power loss, saves the cost of replacing rollers and spare parts, and reduces work delays and time delays.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, specifically to a control method and system for a furnace outlet heat preservation roller conveyor. Background Technology

[0002] In steel rolling mills that primarily produce rebar of 20mm and above and round steel of 82mm and below, the heating furnaces are regenerative walking beam furnaces. A section of insulated roller conveyor runs outside the furnace. Because this insulated roller conveyor is controlled by a frequency converter, it operates at a relatively high frequency for extended periods during production (to facilitate billet entry into the rolling mill). The billet exit time is adjusted to control the billet exit from the heating furnace. This long-term operation presents the following problems: ① After the billet enters the rolling mill, the mill's linear speed is significantly lower than the insulated roller conveyor's linear speed, causing severe wear on the rollers behind the insulated roller conveyor; ② It results in wasted electrical energy; ③ If the worn roller conveyors are not replaced in time, the billet head, when running at the worn position, will be lower than the insulated roller conveyor's surface, causing it to collide with the rollers behind it. This leads to damage to the roller bearings, reduced roller conveyor transmission efficiency, and collisions with the roll inlet guides. When the billet has difficulty entering the rolling mill, operators further increase the insulated roller conveyor speed, which worsens the situation, frequently resulting in the billet failing to enter the rolling mill, causing delays. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides a control method and system for the furnace outlet heat preservation roller conveyor, in order to solve at least one of the above-mentioned technical problems.

[0004] According to one aspect of the present invention, a method for controlling a furnace outlet heat-preserving roller conveyor is provided, the method comprising:

[0005] A first thermal detector is installed next to the starting roller of the heat preservation roller conveyor, and a second thermal detector is installed next to the ending roller of the heat preservation roller conveyor. The first thermal detector is close to the heating furnace, and the second thermal detector is close to the rolling mill.

[0006] When the first thermal detector detects the steel billet, the speed of the roller conveyor in the heating furnace is switched to keep it synchronized with the speed of the heat preservation roller conveyor.

[0007] When the current steel billet enters the rolling mill along the heat-insulating roller table and receives the bite signal, switch the speed of the heat-insulating roller table to keep it synchronized with the rolling mill speed.

[0008] When the second thermal detector detects the arrival of the falling edge of the signal, the speed of the heat preservation roller is increased, so that the next steel billet moves forward quickly along the heat preservation roller until the next bite signal arrives.

[0009] The above technical solution avoids roller wear and power consumption by adjusting the speed of the heat preservation roller conveyor, saves the cost of replacing roller conveyors and spare parts, and reduces downtime.

[0010] As a further technical solution, the method also includes: when receiving the next bite signal, switching the speed of the heat preservation roller table to keep it synchronized with the rolling mill speed.

[0011] As a further technical solution, the method also includes: when the second thermal detector detects the arrival of the signal falling edge, determining the height adjustment speed of the heat preservation roller table based on the distance between the previous steel billet and the next steel billet.

[0012] As a further technical solution, the method also includes: when the second thermal detector detects the arrival of the falling edge of the signal, determining the height adjustment speed of the heat preservation roller conveyor by adjusting the steel delay.

[0013] As a further technical solution, the distance between the second thermal detector and the rolling mill is less than the length of the steel billet.

[0014] As a further technical solution, the method further includes: after the first thermal detector detects the billet signal and the signal lasts for a preset time, a steel demand signal is sent.

[0015] As a further technical solution, the method also includes: after the steel demand signal is issued, the steel feeding operation is started after a set steel demand delay time.

[0016] According to one aspect of the present invention, a control system for a furnace outlet heat preservation roller conveyor is provided, comprising a PLC controller configured to: be connected to the heat preservation roller conveyor for controlling the running speed of the heat preservation roller conveyor; be connected to the furnace outlet roller conveyor inside the heating furnace for controlling the running speed of the furnace outlet roller conveyor; be connected to a first thermal detector for switching the speed of the furnace outlet roller conveyor according to the signal from the first thermal detector; be connected to a second thermal detector for switching the speed of the heat preservation roller conveyor according to the signal from the second thermal detector; and be connected to a human-machine interface for setting and displaying mill parameters.

[0017] As a further technical solution, the mill parameters include, but are not limited to, rolling specifications, final rolling speed, rolling parameter table, and steel demand delay.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention adjusts the speed of the insulation roller table to keep it synchronized with the speed of the rolling mill after the billet is bitten into the rolling mill, thus avoiding the problem of severe wear on the surface of the rollers behind the insulation roller table due to the rolling mill's linear speed being lower than that of the insulation roller table.

[0020] When the second thermal detector detects the falling edge of the signal, the present invention increases the speed of the heat preservation roller, so that the subsequent steel billet moves forward quickly. In the best case, it can control the next steel billet to catch up with the previous steel billet at the rolling mill, thereby improving the utilization rate and avoiding the waste of electricity caused by the previous steel billet being thrown away while the next steel billet is still far away from the rolling mill. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the control method for the furnace outlet heat preservation roller conveyor according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the furnace outlet heat preservation roller conveyor according to an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of various embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

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

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

[0027] In existing rolling mill operation, the mill's linear speed is significantly lower than the linear speed of the insulation roller conveyor after the billet bites into the mill, causing severe wear on the roller surfaces of the rollers behind the insulation roller conveyor. Furthermore, the large distance between the preceding and following billets results in wasted electrical energy. In addition, if the roller conveyors are not replaced in time after wear, the billet head will run at a lower elevation than the insulation roller conveyor surface when it is at the worn position, causing it to collide with the rollers behind it, resulting in damage to the roller bearings, reduced roller conveyor transmission efficiency, and collision with the roll inlet guides. When the billet has difficulty biting into the mill, the existing technology allows operators to further increase the speed of the insulation roller conveyor, which will further worsen the situation, leading to timeouts due to the billet not being able to bite into the mill.

[0028] This invention provides a control method for the furnace outlet heat preservation roller conveyor, which adjusts the speed of the heat preservation roller conveyor in a targeted manner, avoiding roller conveyor wear and power consumption, saving the cost of replacing roller conveyors and spare parts, and reducing downtime.

[0029] like Figure 1 As shown, the method includes:

[0030] A first thermal detector is installed next to the starting roller of the heat preservation roller conveyor, and a second thermal detector is installed next to the ending roller of the heat preservation roller conveyor. The first thermal detector is close to the heating furnace, and the second thermal detector is close to the rolling mill.

[0031] When the first thermal detector detects the steel billet, the speed of the roller conveyor in the heating furnace is switched to keep it synchronized with the speed of the heat preservation roller conveyor.

[0032] When the current steel billet enters the rolling mill along the heat-insulating roller table and receives the bite signal, switch the speed of the heat-insulating roller table to keep it synchronized with the rolling mill speed.

[0033] When the second thermal detector detects the arrival of the falling edge of the signal, the speed of the heat preservation roller is increased, so that the next steel billet moves forward quickly along the heat preservation roller until the next bite signal arrives.

[0034] Optionally, the method further includes: upon receiving the next bite signal, switching the speed of the heat-insulating roller table to synchronize it with the mill speed.

[0035] Optionally, the method further includes: when the second thermal detector detects the arrival of the falling edge of the signal, determining the height adjustment speed of the heat preservation roller conveyor based on the distance between the previous billet and the next billet.

[0036] Optionally, the method further includes: determining the height adjustment speed of the heat preservation roller conveyor by adjusting the steel delay when the second thermal detector detects the arrival of the falling edge of the signal.

[0037] Optionally, the distance between the second thermal detector and the rolling mill is less than the length of the billet.

[0038] Optionally, the method further includes: sending a steel billet demand signal after the first thermal detector detects the billet signal and the signal persists for a preset time. The preset time can be 2.5 seconds.

[0039] Optionally, the method further includes: after the steel demand signal is issued, the steel feeding operation begins only after a set steel demand delay time has elapsed. The steel demand delay setting varies slightly depending on the specifications and rolling adjustment parameters, but is generally 4 to 6 seconds.

[0040] This invention also provides a control system for a furnace outlet heat-preserving roller conveyor, including a PLC controller. The PLC controller is configured to: connect to the heat-preserving roller conveyor for controlling its operating speed; connect to the furnace outlet roller conveyor for controlling its operating speed; connect to a first thermal detector for switching the speed of the furnace outlet roller conveyor based on the signal from the first thermal detector; connect to a second thermal detector for switching the speed of the heat-preserving roller conveyor based on the signal from the second thermal detector; and connect to a human-machine interface for setting and displaying mill parameters. The system is used to implement the steps of the method described in this invention.

[0041] like Figure 2 As shown, the left side is the heating furnace. The first roller conveyor next to the heating furnace is the last one for exiting the furnace. Rollers numbered 2 to 10 from left to right are the heat preservation roller conveyors. Behind them are the pinch rolls, and then the No. 1 rolling mill. The steel billets used are 160mm*160mm*9m fixed weight billets.

[0042] During normal production, operators will pre-set parameters such as rolling specifications, final rolling speed, rolling parameter table, and steel demand delay settings in the HMI (Human Machine Interface).

[0043] The automatic steel tapping process is as follows:

[0044] Steel is tapped from the heating furnace, and the red-hot steel passes through the HMD1 heat detector on the heat-insulating roller conveyor. When the heat detector detects a signal, it sends a steel demand signal after 2.5 seconds. After a delay (set by the steel demand delay), the walking beam begins to move. It first rises to lift the steel billet from the furnace, then moves forward, then descends to place the billet on the fixed beam inside the furnace. After descending to the correct position, it retreats to the origin. Each cycle of the walking beam is the same; our heating furnace walking beam cycle is 30 seconds (with very small deviation). When the walking beam has descended about halfway (the billet is exactly placed on the fixed beam), the furnace tapping roller conveyor starts to tap out the first billet from the furnace. It takes approximately 22 seconds from the start of the walking beam movement to the steel being placed on the roller conveyor. This means that the time it takes for the head of the previous steel billet to pass through HMD1 is 2.5 + the time set for the steel demand delay + 22 seconds. The steel demand delay setting varies slightly depending on the specifications and rolling adjustment parameters, but is generally 4 to 6 seconds. At this time, the distance between the head of the steel billet on the furnace roller conveyor and the tail of the previous steel billet is: the distance from the head of the steel billet on the furnace roller conveyor to HMD1 + V_maintain * (2.5 + 4 + 22) - 9, where V_maintain is the speed of the heat preservation roller conveyor. The original speed of the heat preservation roller conveyor is much greater than the speed of the No. 1 rolling mill, and the lack of automatic speed adjustment causes many problems in actual use.

[0045] Calculations show that when the billet falls onto the furnace roller conveyor, the roller conveyor runs at high speed to deliver the red billet. When HMD1 detects the billet, the speed of the furnace roller conveyor switches to synchronize with the heat preservation roller conveyor (to avoid the heat preservation roller conveyor being too slow and the furnace roller conveyor being too fast, causing wear on the furnace roller conveyor floor roller). When the falling edge of the detection signal from HMD2 (HMD2 was originally a heat detector used by the pinch roller; we moved it slightly so that it aligns with the last roller of the heat preservation roller conveyor) arrives, the heat preservation roller conveyor switches to high speed, and the next steel billet starts to catch up with the previous steel billet. The increased speed is roughly adjusted according to the actual distance between the two steel billets. Operators can also optimize this by adjusting the steel demand delay setting, just enough to control the billet to catch up at the No. 1 rolling mill. When the No. 1 rolling mill throws the steel billet and the next bite signal arrives, the speed of the heat preservation roller conveyor decreases to synchronize with the speed of the No. 1 rolling mill, and so on.

[0046] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling a furnace outlet heat-preserving roller conveyor, characterized in that, The method includes: A first thermal detector is installed next to the starting roller of the heat preservation roller conveyor, and a second thermal detector is installed next to the ending roller of the heat preservation roller conveyor. The first thermal detector is close to the heating furnace, and the second thermal detector is close to the rolling mill. After the first thermal detector detects the billet signal and the signal lasts for a preset time, a steel demand signal is issued. After the steel demand signal is issued, and after a set steel demand delay time, the heating furnace begins to tap steel. When the billet is sent to the tapping roller conveyor in the heating furnace and is detected by the first thermal detector, the speed of the roller conveyor in the heating furnace is switched to keep it synchronized with the speed of the heat preservation roller conveyor. When the current steel billet enters the rolling mill along the heat-insulating roller table and receives the bite signal, switch the speed of the heat-insulating roller table to keep it synchronized with the rolling mill speed. When the second thermal detector detects the arrival of the falling edge of the signal, the speed of the heat preservation roller is increased, so that the next steel billet moves forward quickly along the heat preservation roller until the next bite signal arrives.

2. The control method for the furnace outlet heat preservation roller conveyor according to claim 1, characterized in that, The method further includes: upon receiving the next bite signal, switching the speed of the heat preservation roller table to keep it synchronized with the mill speed.

3. The control method for the furnace outlet heat preservation roller conveyor according to claim 1, characterized in that, The method further includes: when the second thermal detector detects the arrival of the falling edge of the signal, determining the height adjustment speed of the heat preservation roller conveyor based on the distance between the previous steel billet and the next steel billet.

4. The control method for the furnace outlet heat preservation roller conveyor according to claim 1, characterized in that, The method further includes: when the second thermal detector detects the arrival of the falling edge of the signal, determining the height adjustment speed of the heat preservation roller conveyor by adjusting the steel delay.

5. The control method for the furnace outlet heat preservation roller conveyor according to claim 1, characterized in that, The distance between the second thermal detector and the rolling mill is less than the length of the billet.

6. The control method for the furnace outlet heat preservation roller conveyor according to claim 1, characterized in that, The method further includes sending a steel billet signal after the first thermal detector detects the billet signal and the signal lasts for a preset time.

7. The control method for the furnace outlet heat preservation roller conveyor according to claim 6, characterized in that, The method further includes: after the steel demand signal is issued, the steel feeding operation is started after a set steel demand delay time.

8. A control system for a furnace outlet heat preservation roller conveyor, characterized in that, The system includes a PLC controller configured to: connect to the heat-insulating roller conveyor for controlling its operating speed; connect to the furnace exit roller conveyor for controlling its operating speed; connect to a first thermal detector for issuing a steel demand signal after the first thermal detector detects a billet signal and the signal persists for a preset time, and switching the speed of the furnace exit roller conveyor to synchronize it with the speed of the heat-insulating track according to the signal from the first thermal detector; connect to a second thermal detector for switching the speed of the heat-insulating roller conveyor according to the signal from the second thermal detector, including: controlling the heat-insulating roller conveyor to switch to synchronization with the mill speed when a steel bite signal is received; controlling the heat-insulating roller conveyor to increase its speed when the second thermal detector detects a falling edge of the signal, wherein the increase speed is coarsely adjusted based on the actual distance between the previous and subsequent billets, and can be optimized by combining the steel demand delay setting; and connect to a human-machine interface for setting and displaying mill parameters.

9. The control system for the furnace outlet heat preservation roller conveyor according to claim 8, characterized in that, The rolling mill parameters include, but are not limited to, rolling specifications, final rolling speed, rolling parameter table, and steel demand delay.

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