System and method for remotely controlling accident water by using PID (Proportion Integration Differentiation) through continuous casting machine

Abstract

The invention belongs to the technical field of steelmaking and continuous casting, and particularly relates to a system and method for remotely controlling accident water through a continuous casting machine by applying PID. The system comprises a first connecting pipe, a machine cooling pump, an accident water tank, an accident water inlet pipe, an accident water return pipe, a second connecting pipe and a PID control unit. A water return port of the continuous casting machine is connected with one end of the machine cooling pump through a first connecting pipe, and the other end of the machine cooling pump is connected with a water inlet of the continuous casting machine through a second connecting pipe. The accident water tank is connected with the second connecting pipe through an accident water inlet pipe; the PID control unit comprises an accident water return valve control unit and a PIC control unit; the accident water return valve control unit is arranged on the accident water return pipe; the PIC control unit is connected with the first connecting pipe; and the accident water return valve control unit is connected with the PIC control unit. Based on the system and the method, the problems that a traditional accident water control method is large in error, insufficient in reliability, weak in anti-interference capacity and high in maintenance cost can be solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steelmaking continuous casting, and particularly relates to a system and method for PID remote control of emergency water for a continuous casting machine. BACKGROUND

[0002] In modern steel continuous casting production, the segment and crystallizer are the core components of the continuous casting equipment, and their stable operation is crucial to the quality of the cast slab and production efficiency. The emergency water system is an important safety guarantee facility for the continuous casting machine. When the conventional cooling water system fails, the emergency water system needs to be quickly started to ensure the cooling of the segment and crystallizer equipment, so as to avoid serious production accidents and equipment damage caused by overheating of the equipment. Therefore, it is of great engineering significance and practical application value to realize reliable and accurate remote control of the emergency water system.

[0003] The traditional remote control mode of the emergency water mainly relies on an electrical control system. The system usually measures the pressure of the pressure point water through an electrical pressure sensor, converts the pressure signal into an electrical signal, and transmits the electrical signal to a controller. The controller outputs an electrical signal to control an electric valve according to a preset control logic, so as to realize the opening and closing control of the emergency water return valve. However, this traditional control mode has obvious limitations. On the one hand, the electrical elements are easily affected by electromagnetic interference, environmental temperature changes, humidity fluctuations and other factors, resulting in large pressure measurement errors, unstable control signal transmission, and thus affecting the response speed and control accuracy of the emergency water system. On the other hand, the electrical elements may age, have poor contact and other problems after long-term operation, increasing the system failure rate and maintenance cost. In addition, the electrical control system needs complex circuit design and power support, and has poor applicability in some special environments (such as high dust, high humidity and strong electromagnetic interference environment), and is difficult to meet the requirements of high reliability and high stability of the emergency water system for continuous casting production. SUMMARY

[0004] To solve the above technical problems, the application discloses a system and method for PID remote control of emergency water for a continuous casting machine, to solve the problems of large measurement error, insufficient reliability, weak anti-interference ability and high maintenance cost of the traditional remote control mode of the emergency water.

[0005] The application provides a system for PID remote control of emergency water for a continuous casting machine, the continuous casting machine having a water inlet and a water return outlet; the system comprising a first connecting pipe, a machine cooling pump, an emergency water tank, an emergency water inlet pipe, an emergency water return pipe, a second connecting pipe and a PID control unit; the water return outlet of the continuous casting machine being connected to one end of the machine cooling pump through the first connecting pipe, the other end of the machine cooling pump being connected to the water inlet of the continuous casting machine through the second connecting pipe; the emergency water tank being connected to the second connecting pipe through the emergency water inlet pipe; the PID control unit comprising an emergency water return valve control unit and a PIC control unit; the emergency water return valve control unit being arranged on the emergency water return pipe; the PIC control unit being connected to the first connecting pipe; and the emergency water return valve control unit being connected to the PIC control unit.

[0006] Further, the PIC control unit comprises a machine cooling water connecting pipe, a pneumatic transmitter, a two-position three-way air control reversing valve A, a first pressure regulating valve and a second pressure regulating valve; the first end of the two-position three-way air control reversing valve A being connected to the emergency water return valve control unit, the second end of the two-position three-way air control reversing valve A being connected to the second pressure regulating valve; the third end of the two-position three-way air control reversing valve A being connected to the first end of the pneumatic transmitter, the second end of the pneumatic transmitter being connected to the first pressure regulating valve; and the third end of the pneumatic transmitter being connected to the first connecting pipe through the machine cooling water connecting pipe.

[0007] Further, the emergency water return valve control unit comprises a PV valve, a two-position three-way air control reversing valve B and a third pressure regulating valve; the PV valve being arranged on the emergency water return pipe; the control end of the PV valve being connected to the first end of the two-position three-way air control reversing valve B, the second end of the two-position three-way air control reversing valve B being connected to the third pressure regulating valve; and the third end of the two-position three-way air control reversing valve B being connected to the first end of the two-position three-way air control reversing valve A.

[0008] Further, the emergency water inlet pipe is provided with a first butterfly valve and a first pneumatic cut-off valve.

[0009] Further, the second connecting pipe is provided with a first check valve; the first connecting pipe is provided with a second pneumatic cut-off valve and a third pneumatic cut-off valve; the emergency water return pipe is provided with a fourth pneumatic cut-off valve, a first ball valve and a second butterfly valve; and the machine cooling water connecting pipe is provided with a second ball valve.

[0010] The application also provides a method for PID remote control of emergency water for a continuous casting machine, the method being based on the system; compressed air A being introduced into the first pressure regulating valve, compressed air B being introduced into the second pressure regulating valve, and compressed air C being introduced into the third pressure regulating valve; the compressed air A entering the pneumatic transmitter through the first pressure regulating valve; the pneumatic transmitter sensing the pressure of the machine cooling water through the machine cooling water connecting pipe; the pressure of the machine cooling water being transmitted to the PIC control unit through the pneumatic transmitter; the PIC control unit sending a signal to the emergency water return valve control unit; the emergency water return valve control unit controlling the opening and closing of the PV valve; and the PV valve being opened or closed according to the signal of the PIC control unit. Before the continuous casting machine starts working, the first butterfly valve, the second butterfly valve, the first ball valve and the second ball valve are opened, and the fourth pneumatic cut-off valve is closed; the second pneumatic cut-off valve and the third pneumatic cut-off valve are opened, and the machine cooling pump is opened; when the pressure of the machine cooling water reaches a set balance value, the first pneumatic cut-off valve is opened, and the fourth pneumatic cut-off valve is opened; When the continuous casting machine works normally, the pressure of the machine cooling water in the pneumatic transmitter and the pressure of the compressed air A are balanced, the first end of the pneumatic transmitter has no gas pressure, and the emergency water return valve control unit is not actuated; If the continuous casting machine does not work normally, the pressure of the machine cooling water in the pneumatic transmitter and the pressure of the compressed air A are not balanced, the first end of the pneumatic transmitter has gas pressure, which drives the two-position three-way pneumatic reversing valve A to act, the compressed gas B passes through the second pressure regulating valve and the two-position three-way pneumatic reversing valve A to drive the two-position three-way pneumatic reversing valve B to act, the compressed gas C passes through the third pressure regulating valve and the two-position three-way pneumatic reversing valve B to drive the PV valve to open; the emergency water in the emergency water tank enters the first connecting pipe to cool the continuous casting machine.

[0011] The beneficial effects of the present application are: (1) Accurate measurement: the pneumatic transmitter accurately measures the pressure of the pressure point water and compares it with the compressed air A in real time, and uses a pure mechanical structure to realize the conversion and transmission of the pressure signal, avoiding the measurement error of electrical elements and other adverse factors, and more accurately reflecting the actual pressure state, providing a reliable basis for the control of the emergency water system.

[0012] (2) High reliability: the pneumatic transmitter is a mechanical device without electrical elements, and there are no problems such as electrical element aging and electromagnetic interference, which can stably operate in harsh environments such as high dust, high humidity and strong electromagnetic interference, greatly improving the reliability and stability of the emergency water system.

[0013] (3) Strong anti-interference ability: the pneumatic signal transmission and control are not affected by electromagnetic interference, the signal transmission is stable, and the accurate transmission and execution of control instructions in complex industrial environments can be ensured.

[0014] (4) Low maintenance cost: the use of electrical elements is reduced, the maintenance demand caused by electrical element failure is reduced, and the structure of the pneumatic device is relatively simple and easy to maintain, which can effectively reduce the maintenance cost of the system. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic diagram of the PID control unit of the present application; Figure 2 is a schematic diagram of the system of the present application.

[0016] MARKING OF THE DRAWINGS 1, first butterfly valve, 2, first pneumatic cut-off valve, 3, pipeline reducing, 4, second ball valve, 5, second check valve, 6, first check valve, 7, machine cooling pump, 8, second pneumatic cut-off valve, 9, third pneumatic cut-off valve, 10, first ball valve, 11, fourth pneumatic cut-off valve, 12, PID control unit, 13, second butterfly valve. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other manners different from those described herein, and those skilled in the art can make similar generalizations without departing from the concept of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0018] The present application discloses a system and method for PID remote control of emergency water for a continuous casting machine, to solve the problems of large measurement error, insufficient reliability, weak anti-interference ability and high maintenance cost of traditional emergency water remote control mode.

[0019] The present application discloses a system for PID remote control of emergency water for a continuous casting machine, specifically, the system of the present application is used on a crystallizer of a continuous casting machine. The crystallizer of the continuous casting machine has a water inlet and a backwater outlet.

[0020] The system includes a first connecting pipe, a machine cooling pump 7, an emergency water tank, an emergency water inlet pipe, an emergency water backwater pipe, a second connecting pipe and a PID control unit 12, as shown in Figures 1-2 .

[0021] The backwater outlet of the crystallizer of the continuous casting machine (the "equipment" in Figure 2 ) is connected to one end of the machine cooling pump 7 through the first connecting pipe, the other end of the machine cooling pump 7 is connected to the water inlet of the crystallizer of the continuous casting machine through the second connecting pipe, and the first connecting pipe and the second connecting pipe are filled with machine cooling water. The third pneumatic cut-off valve 9 and the second pneumatic cut-off valve 8 are arranged on the first connecting pipe, wherein the second pneumatic cut-off valve 8 is located closer to the machine cooling pump 7. The first check valve 6 is arranged on the second connecting pipe. The emergency water from the backwater outlet of the crystallizer of the continuous casting machine passes through the third pneumatic cut-off valve 9 and the second pneumatic cut-off valve 8 into the machine cooling pump 7 for cooling, and then reenters the crystallizer of the continuous casting machine from the water inlet through the first check valve 6, thereby forming a machine cooling water circulation loop, as shown in Figure 2 .

[0022] The emergency water tank is arranged at a high position. The emergency water tank is connected to the second connecting pipe through the emergency water inlet pipe, and the connection point of the emergency water inlet pipe and the second connecting pipe is between the first check valve 6 and the water inlet.

[0023] The first butterfly valve 1, the first pneumatic cut-off valve 2 and the second check valve 5 are arranged on the accident water inlet pipe; the accident water inlet pipe can also be provided with a pipe diameter reducer 3 to adjust the pipe diameter of the accident water inlet pipe, so that the accident water inlet pipe and the second connecting pipe can be normally connected. When necessary, the accident water in the accident water tank enters the second connecting pipe through the first butterfly valve 1, the first pneumatic cut-off valve 2, the second check valve 5 and the pressure difference of the high position, and is supplied to the continuous casting machine for cooling.

[0024] The accident water return pipe is connected with the first connecting pipe, and the connection point of the accident water return pipe and the first connecting pipe is between the third pneumatic cut-off valve 9 and the water return port. The second butterfly valve 13, the accident water return valve control unit, the fourth pneumatic cut-off valve 11 and the first ball valve 10 are arranged on the accident water return pipe from one end to the other end of the first connecting pipe in sequence. The other end of the accident water return pipe can be arranged at a ditch.

[0025] The second connecting pipe is also connected with a PIC control unit through the machine cooling water connecting pipe. The PIC control unit is connected with the accident water return valve control unit. The PIC control unit and the accident water return valve control unit jointly constitute a PID control unit 12.

[0026] As shown in Figure 1 , the PIC control unit comprises a machine cooling water connecting pipe, a pneumatic transmitter, a two-position three-way air control reversing valve A, a first pressure regulating valve and a second pressure regulating valve. The first end of the two-position three-way air control reversing valve A is connected with the accident water return valve control unit, and the second end of the two-position three-way air control reversing valve A is connected with the second pressure regulating valve. The third end of the two-position three-way air control reversing valve A is connected with the first end of the pneumatic transmitter through an outlet air source pipe, the second end of the pneumatic transmitter is connected with the first pressure regulating valve, and the third end of the pneumatic transmitter is connected with the second connecting pipe through the machine cooling water connecting pipe. The second ball valve 4 is arranged on the machine cooling water connecting pipe. The first pressure regulating valve is connected with compressed air A, and the second pressure regulating valve is connected with compressed air B. The compressed air A passes through the first pressure regulating valve to set a suitable comparison pressure corresponding to the pressure of the machine cooling water, and is used for comparison with the pressure of the machine cooling water.

[0027] The accident water return valve control unit comprises a PV valve, a two-position three-way air control reversing valve B and a third pressure regulating valve. The PV valve is arranged on the accident water return pipe. The control end of the PV valve is connected with the first end of the two-position three-way air control reversing valve B, the second end of the two-position three-way air control reversing valve B is connected with the third pressure regulating valve, and the third end of the two-position three-way air control reversing valve B is connected with the first end of the two-position three-way air control reversing valve A. The third pressure regulating valve is connected with compressed air C.

[0028] The present application realizes PID control by using a pneumatic transmitter. A branch pipe (machine cooling water connecting pipe) is installed on the second connecting pipe and connected to the water pressure measurement inlet point (the third end of the pneumatic transmitter) of the PID control unit 12, so that the pressure of the machine cooling water is measured.

[0029] In normal working condition, the pressure of compressed gas A in the pneumatic transmitter of the PID control unit 12 is balanced with the pressure of the machine cooling water, the outlet gas source pipe of the first end of the pneumatic transmitter of the PID control unit 12 has no gas pressure, and the emergency water return valve control unit has no action.

[0030] In abnormal working condition (i.e. the pressure of the machine cooling water is reduced to a certain value), the pressure of compressed gas A in the pneumatic transmitter of the PID control unit 12 is greater than the pressure of the machine cooling water, the first end of the pneumatic transmitter of the PID control unit 12 has gas pressure, which drives the two-position three-way pneumatic reversing valve A 15 to act, at this time, compressed air B passes through the two-position three-way pneumatic valve A 15, drives the two-position three-way pneumatic valve B 16 to act, and compressed air C passes through the two-position three-way pneumatic valve B to drive the PV valve to act (open the PV valve), and the emergency water in the emergency water tank enters the second connecting pipe through the pipeline for cooling use.

[0031] Based on this, the application further discloses a method for PID remote control of emergency water of a continuous casting machine, before the continuous casting machine starts to work, the first butterfly valve 1, the second butterfly valve 13, the first ball valve 10 and the second ball valve 4 are opened, and the fourth pneumatic cut-off valve 11 is closed; the second pneumatic cut-off valve 8 and the third pneumatic cut-off valve 9 are opened, and the machine cooling pump 7 is opened, when the pressure of the machine cooling water reaches a set balance value, the first pneumatic cut-off valve 2 is opened, and the fourth pneumatic cut-off valve 11 is opened.

[0032] In normal working condition of the continuous casting machine, the pressure of the machine cooling water in the pneumatic transmitter is balanced with the pressure of compressed air A, the first end of the pneumatic transmitter has no gas pressure, and the emergency water return valve control unit has no action.

[0033] If the continuous casting machine works abnormally, the pressure of the machine cooling water in the pneumatic transmitter is not balanced with the pressure of compressed air A, the first end of the pneumatic transmitter has gas pressure, which drives the two-position three-way pneumatic reversing valve A to act, compressed gas B passes through the second pressure regulating valve and the two-position three-way pneumatic reversing valve A to drive the two-position three-way pneumatic reversing valve B to act, compressed gas C passes through the third pressure regulating valve and the two-position three-way pneumatic reversing valve B to drive the PV valve to open, and the emergency water in the emergency water tank enters the first connecting pipe to cool the continuous casting machine.

[0034] Specifically, taking the emergency water of a crystallizer of a certain continuous casting and rolling continuous casting machine as an example, the normal working water flow of the wide surface of the crystallizer is 7000-8000 L / min, the normal working water flow of the narrow surface of the crystallizer is 490-560 L / min, the normal working pressure of the cooling water (machine cooling water) in the crystallizer is 16.4 bar (a set balance value), and the continuous casting machine takes the OMC-80 series pneumatic transmitter as the PID control unit 12 to realize remote control of the emergency water.

[0035] 1. The cooling water pressure of the crystallizer equipment with a flow rate of 50% of the normal working water flow rate on the wide and narrow copper plates of the crystallizer is set as 6 bar as the low alarm value. To ensure the safety of the crystallizer operation, 7 bar is set as the alarm value for the crystallizer to start in case of emergency water flow (that is, the set pressure for the PID control unit 12 to execute the action). When the cooling water pressure of the crystallizer equipment is lower than 7 bar, the PID control unit starts to execute the action.

[0036] 2. Before the continuous casting machine starts pouring steel, set the first butterfly valve 1, the second butterfly valve 13, the second ball valve 4, and the first ball valve 10 to the open state, and close the fourth pneumatic shut-off valve 11. Open the second pneumatic shut-off valve 8 and the third pneumatic shut-off valve 9, start the machine cooling pump 7, and maintain the pressure when the pressure of the cooling water reaches 16.4 bar. Then open the first pneumatic shut-off valve 2 and the fourth pneumatic shut-off valve 11.

[0037] 3. During normal steel pouring, the machine cooling water will not enter the emergency water inlet pipe due to the second check valve 5.

[0038] 4. Under abnormal operating conditions (such as steel leakage in the crystallizer or a rupture in the cooling water pipeline), when the pressure of the cooling water in the continuous casting machine's crystallizer drops to 7 bar, the PID control unit 12 is activated, ultimately opening the PV valve. Due to the pressure difference caused by the height difference in the high-level water tank, the emergency water enters the crystallizer of the continuous casting machine for cooling. Because of the first check valve 6, the emergency water can only enter through the first connecting pipe from the inlet and then flow out from the outlet of the crystallizer. The emergency water continues to flow for 30 minutes before finally draining into the drainage ditch.

[0039] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A system for remotely controlling emergency water using PID for a continuous casting machine, characterized by, The continuous casting machine has a water inlet and a water outlet; the system comprises a first connecting pipe, a machine cooling pump, an emergency water tank, an emergency water inlet pipe, an emergency water outlet pipe, a second connecting pipe and a PID control unit; the water outlet of the continuous casting machine is connected to one end of the machine cooling pump through the first connecting pipe, the other end of the machine cooling pump is connected to the water inlet of the continuous casting machine through the second connecting pipe; the emergency water tank is connected to the second connecting pipe through the emergency water inlet pipe; the PID control unit comprises an emergency water outlet valve control unit and a PIC control unit; the emergency water outlet valve control unit is arranged on the emergency water outlet pipe; the PIC control unit is connected to the first connecting pipe; the emergency water outlet valve control unit is connected to the PIC control unit.

2. A system for remotely controlling emergency water using PID for a continuous casting machine according to claim 1, characterized in that, The PIC control unit comprises a machine cooling water connecting pipe, a pneumatic transmitter, a two-position three-way pneumatic reversing valve A, a first pressure regulating valve and a second pressure regulating valve; the first end of the two-position three-way pneumatic reversing valve A is connected to the emergency water outlet valve control unit, the second end of the two-position three-way pneumatic reversing valve A is connected to the second pressure regulating valve; the third end of the two-position three-way pneumatic reversing valve A is connected to the first end of the pneumatic transmitter, the second end of the pneumatic transmitter is connected to the first pressure regulating valve; the third end of the pneumatic transmitter is connected to the first connecting pipe through the machine cooling water connecting pipe.

3. The system for remotely controlling the emergency water using PID for a continuous casting machine according to claim 2, wherein The emergency water outlet valve control unit comprises a PV valve, a two-position three-way pneumatic reversing valve B and a third pressure regulating valve; the PV valve is arranged on the emergency water outlet pipe; the control end of the PV valve is connected to the first end of the two-position three-way pneumatic reversing valve B, the second end of the two-position three-way pneumatic reversing valve B is connected to the third pressure regulating valve; the third end of the two-position three-way pneumatic reversing valve B is connected to the first end of the two-position three-way pneumatic reversing valve A.

4. The system for remotely controlling the emergency water using PID for a continuous casting machine according to claim 3, wherein A first butterfly valve and a first pneumatic cut-off valve are arranged on the emergency water inlet pipe.

5. The system for remotely controlling the emergency water using PID for a continuous casting machine according to claim 4, wherein A first check valve is arranged on the second connecting pipe; a second pneumatic cut-off valve and a third pneumatic cut-off valve are arranged on the first connecting pipe; a fourth pneumatic cut-off valve, a first ball valve and a second butterfly valve are arranged on the emergency water outlet pipe; a second ball valve is arranged on the machine cooling water connecting pipe.

6. A method for remotely controlling the emergency water using PID for continuous casting machine, the method is implemented based on the system of claim 5, characterized in that, The first pressure regulating valve is connected to compressed air A, the second pressure regulating valve is connected to compressed air B, and the third pressure regulating valve is connected to compressed air C; The compressed air A enters the pneumatic transmitter through the first pressure regulating valve, and the pneumatic transmitter senses the pressure of the machine cooling water through the machine cooling water connecting pipe; Before the continuous casting machine starts to work, the first butterfly valve, the second butterfly valve, the first ball valve and the second ball valve are opened, and the fourth pneumatic cut-off valve is closed; the second pneumatic cut-off valve and the third pneumatic cut-off valve are opened, and the machine cooling pump is opened; when the pressure of the machine cooling water reaches a set balance value, the first pneumatic cut-off valve is opened, and the fourth pneumatic cut-off valve is opened; When the continuous casting machine works normally, the pressure of the machine cooling water in the pneumatic transmitter and the pressure of the compressed air A are balanced, the first end of the pneumatic transmitter has no gas pressure, and the emergency water outlet valve control unit has no action; When the continuous casting machine is not working normally, the pressure of the machine cooling water in the pneumatic transmitter and the pressure of the compressed air A are not balanced, the first end of the pneumatic transmitter has gas pressure, which drives the two-position three-way pneumatic reversing valve A to act, the compressed gas B passes through the second pressure regulating valve and the two-position three-way pneumatic reversing valve A to drive the two-position three-way pneumatic reversing valve B to act, the compressed gas C passes through the third pressure regulating valve and the two-position three-way pneumatic reversing valve B to drive the PV valve to open; the emergency water in the emergency water tank enters the first connecting pipe to cool the continuous casting machine.

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