PLC-based water descaling control system

Abstract

This utility model relates to the field of control technology, and in particular to a PLC-based water descaling control system. It includes a heating furnace host computer, a heating furnace sequential control PLC, a water descaling PLC, an oil pump motor, a frequency converter, indicator lights, local operation buttons, a circulation valve, a jet valve, a pressure transmitter, detection switches, and a descaling pump motor. The heating furnace host computer is connected to the heating furnace sequential control PLC via optical fiber. The heating furnace sequential control PLC is connected to the water descaling PLC via cable. The output terminal of the water descaling PLC is connected to the frequency converter, and the output terminal of the frequency converter is connected to the descaling pump motor. The multi-function input terminal of the frequency converter is connected to the digital output terminal of the water descaling PLC and the input terminal of the oil pump motor. This utility model enables local and remote control of the water descaling process, saving manpower and resources. It also automates the operation of the water descaling equipment through the control of detection switches and valves, ensuring the accuracy and safety of the descaling process.

Description

Technical Field

[0001] This utility model relates to the field of control technology, and in particular to a PLC-based water descaling control system. Background Technology

[0002] The primary water descaling system in a steel rolling production line is located between the furnace exit roller conveyor and the roughing mill. It removes iron oxide scale from the surface of the steel billet, ensuring surface quality during the rolling process. This primary water descaling equipment is a reused system; its control is limited to on-site electrical control boxes for starting and stopping oil pumps, descaling pumps, and other equipment, as well as monitoring their operational status. Furnace operators must travel to the furnace electrical room to start and stop the primary water descaling system as needed during the rolling process. However, due to limited personnel, the descaling system may not start even after the billet has passed through the furnace. Starting the descaling system prematurely wastes energy, especially during trial rolling when there is no fixed time for steel output. To save electricity, operators must frequently travel back and forth to start and stop the equipment on-site. This frequent operation can even lead to operator negligence, such as forgetting to stop the descaling pump, resulting in significant energy waste. Utility Model Content

[0003] This invention provides a PLC-based water descaling control system that enables local and remote control of water descaling, saving manpower and resources. It also enables automated operation of the water descaling equipment by detecting switches and controlling valves, ensuring the accuracy and safety of the descaling process.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A PLC-based water descaling control system includes a heating furnace host computer, a heating furnace sequential control PLC, a water descaling PLC, an oil pump motor, a frequency converter, indicator lights, local operation buttons, a circulation valve, a jet valve, a pressure transmitter, a detection switch, and a descaling pump motor. The heating furnace host computer is connected to the heating furnace sequential control PLC via optical fiber. The heating furnace sequential control PLC is connected to the water descaling PLC via cable. The output terminal of the water descaling PLC is connected to the frequency converter, and the output terminal of the frequency converter is connected to the descaling pump motor. The multi-function input terminal of the frequency converter is connected to the digital output terminal and the oil pump motor input terminal of the water descaling PLC. The pressure transmitter is connected to the analog input terminal of the water descaling PLC. The local operation buttons are connected to the digital input terminal of the water descaling PLC. The indicator lights, circulation valve, and jet valve are connected to the digital output terminal of the water descaling PLC. The detection switches include a pump set oil circuit pressure switch, a circulation valve open position proximity switch, a circulation valve close position proximity switch, a billet arrival detector, an injection valve open position proximity switch, and an injection valve close position proximity switch. The pump set oil circuit pressure switch, circulation valve open position proximity switch, circulation valve close position proximity switch, billet arrival detector, injection valve open position proximity switch, and injection valve close position proximity switch are connected to the digital input terminal of the water descaling PLC.

[0005] Furthermore, it also includes a touch screen and a DP coupler. The touch screen is connected to the DP coupler via a PROFIBUS-DP communication cable, and the DP coupler is connected to the water descaling PLC via a PROFIBUS-DP communication cable.

[0006] Furthermore, the heating furnace sequential control PLC includes a power supply module, a CPU module, a digital input module, and a digital output module. The power supply module supplies power to the CPU module. The input terminals of the digital input module are connected to the output terminals of the water descaling PLC for displaying the start and stop of the oil pump on the heating furnace sequential control PLC. The output terminals of the digital output module are connected to the digital input terminals of the water descaling PLC for sending remote start / stop signals from the water descaling PLC to the water descaling PLC.

[0007] Furthermore, the local operation buttons include a descaling pump motor start button, a descaling pump motor stop button, an oil pump motor start button, an oil pump motor stop button, a circulation valve open button, a circulation valve close button, a system manual / automatic switch button, a system emergency stop button, and an alarm clear button.

[0008] Furthermore, the indicator lights include a descaling pump motor running light, a descaling pump motor stopping light, an oil pump motor running light, an oil pump motor stopping light, a circulation valve running light, a circulation valve stopping light, an injection valve running light, an injection valve stopping light, a descaling pump inlet pressure too high alarm light, a descaling pump inlet pressure too low alarm light, an oil pump thermal protection alarm light, a billet arrival indicator light, and a system fault buzzer alarm.

[0009] Furthermore, the water descaling PLC includes a power supply module, a CPU module, an analog input module, a digital input module, and a digital output module. The power supply module supplies power to the CPU module, the analog input module is connected to the pressure transmitter, the digital input module is connected to the local operation button and the detection switch, and the digital output module is connected to the indicator light, the circulation valve, the injection valve, the frequency converter, and the oil pump motor.

[0010] Furthermore, it also includes relays. The output terminals of the heating furnace sequential control PLC digital output module are electrically connected to the digital input terminals of the water descaling PLC through relays. The digital output module of the water descaling PLC is electrically connected to indicator lights, circulation valves, injection valves, frequency converters, and oil pump motors through relays.

[0011] Compared with the prior art, the beneficial effects of this utility model are: 1) Through real-time monitoring of pressure transmitters, pump group oil circuit pressure switches, circulation valve open position proximity switches, circulation valve closed position proximity switches, billet arrival detectors, injection valve open position proximity switches and injection valve closed position proximity switches, combined with the control function of PLC, the key parameters of the water descaling system, such as pressure, flow rate, billet precise position, and valve opening and closing, remain stable, thus ensuring the effectiveness of water descaling. 2) The touch screen and the heating furnace host computer provide an intuitive local and remote operation interface, which simplifies parameter adjustment and system monitoring. The entire system has a high degree of automation, reduces manual intervention, and lowers the labor intensity of operators. The touch screen communicates with the water descaling PLC through a DP coupler, ensuring the stability of data transmission. 3) By connecting the circulation valve and the injection valve to the PLC, their switching can be controlled as needed, avoiding unnecessary energy waste. At the same time, the stable operating pressure also reduces the impact on key equipment such as pumps and valves, which helps to extend their service life. Attached Figure Description

[0012] Figure 1 This is a wiring diagram of the digital input module of the heating furnace sequential control PLC of this utility model.

[0013] Figure 2 This is a wiring diagram of the PLC digital output module for sequential control of the heating furnace of this utility model.

[0014] Figure 3 This is a schematic diagram of the structure of the water descaling PLC described in this utility model.

[0015] Figure 4 This is a wiring diagram of the indicator light described in this utility model.

[0016] Figure 5 This is a wiring diagram of the PLC digital input module for water descaling in this utility model.

[0017] Figure 6 This is a wiring diagram of the PLC digital output module for water descaling in this utility model.

[0018] Figure 7 This is a wiring diagram of the PLC analog input module for water descaling in this utility model.

[0019] Figure 8 This is a wiring diagram of the motor of the No. 1 descaling pump described in this utility model.

[0020] Figure 9 This is a wiring diagram of the motor of the No. 2 descaling pump described in this utility model.

[0021] Figure 10 This is a wiring diagram of the oil pump motor described in this utility model. Detailed Implementation

[0022] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings: This utility model discloses a PLC-based water descaling control system, which includes a heating furnace host computer, a heating furnace sequential control PLC, a water descaling PLC, an oil pump motor, a frequency converter, indicator lights, local operation buttons, a circulation valve, a jet valve, a pressure transmitter, a detection switch, a relay, a descaling pump motor, a touch screen, and a DP coupler.

[0023] In this embodiment, there are two descaling pump motors and two corresponding oil pump motors, and two frequency converters are also set up to control the descaling pump motors.

[0024] The detection switches include oil circuit pressure switches for pump groups 1 and 2, proximity switches for circulating valve open and closed, billet arrival detectors, proximity switches for injection valve open and closed.

[0025] The local operation buttons include: Descaling pump motor start button SB1, Descaling pump motor stop button SD1, Descaling pump motor start button SB3, Descaling pump motor stop button SD3, Oil pump motor start button SB2, Oil pump motor stop button SD2, Oil pump motor start button SB4, Oil pump motor stop button SD4, Circulation valve open button SB5, Circulation valve close button SD5, Standby open button SB6, Standby close button SD6, System manual / automatic switch button SD7, System emergency stop button SA1, Standby SA2, and Alarm clear button E-STOP.

[0026] The indicator lights include: GN1 (No. 1 descaling pump motor running light), RD1 (No. 1 descaling pump motor stop light), GN2 (No. 1 oil pump motor running light), RD2 (No. 1 oil pump motor stop light), GN3 (No. 2 descaling pump motor running light), RD3 (No. 2 descaling pump motor stop light), GN4 (No. 2 oil pump motor running light), RD4 (No. 2 oil pump motor stop light), GN5 (circulation valve running light), RD5 (circulation valve stop light), GN6 (injection valve running light), RD6 (injection valve stop light), HL1 (No. 1 descaling pump inlet pressure too high alarm light), HL2 (No. 1 descaling pump inlet pressure too low alarm light), HL3 (No. 2 descaling pump inlet pressure too high alarm light), HL4 (No. 2 descaling pump inlet pressure too low alarm light), HL5 (No. 1 oil pump thermal protection alarm light), HL6 (No. 2 oil pump thermal protection alarm light), HL7 (billet arrival indicator light), and HA (system fault buzzer alarm).

[0027] See Figure 3-7The water descaling PLC includes a power supply module, a CPU module, an analog input module, a digital input module, and a digital output module. The power supply module supplies power to the CPU module. The two analog input channels of the analog input module are respectively connected to two pressure transmitters SP1 and SP2 that detect the inlet pressure of descaling pumps No. 1 and No. 2. The first eight input channels of the digital input module are correspondingly connected to the motor start button SB1, motor stop button SD1, motor start button SB3, motor stop button SD3, oil pump motor start button SB2, oil pump motor stop button SD2, oil pump motor start button SB4, and oil pump motor stop button SD4 of descaling pump No. 1. The second eight channels of the digital input module are correspondingly connected to the circulation valve open button S. B5, Circulation valve close button SD5, Standby open button SB6, Standby close button SD6, System manual / automatic switch button SD7, System emergency stop button SA1, Standby button SA2, and Alarm clear button E-STOP; The third eight channels of the digital input module are respectively connected to the normally open contacts of contactor KM1, thermal relay FR1, contactor KM2, thermal relay FR2, relay KA1, relay KA2, relay KA3, and relay KA4, used to input the operation and fault signals of 2 oil pump motors and 2 frequency converters; The fourth eight channels of the digital input module are respectively connected to the oil circuit pressure switch 1PL of pump group 1, the oil circuit pressure switch 2PL of pump group 2, the circulation valve open proximity switch, the circulation valve closed proximity switch, the billet arrival detector, the injection valve open proximity switch, and the injection valve closed proximity switch; The 32 output channels of the digital output module are connected to the coils of relays K1-K32. The normally open contact of relay K1 is connected to the running light GN1 of the No. 1 descaling pump motor, and the normally closed contact of relay K1 is connected to the stop light RD1 of the No. 1 descaling pump motor. The normally open contact of relay K2 is connected to the running light GN2 of the No. 1 oil pump motor, and the normally closed contact of relay K2 is connected to the stop light RD2 of the No. 1 oil pump motor. The normally open contact of relay K3 is connected to the running light GN3 of the No. 1 descaling pump motor, and the normally closed contact of relay K3 is connected to the stop light RD1 of the No. 1 descaling pump motor. 3. The normally open contact of relay K4 is connected to the No. 1 oil pump motor running light GN4, and the normally closed contact of relay K4 is connected to the No. 1 oil pump motor stop light RD4. The normally open contact of relay K5 is connected to the circulation valve running light GN5, and the normally closed contact of relay K5 is connected to the circulation valve stop light RD5. The normally open contact of relay K6 is connected to the injection valve running light GN6, and the normally closed contact of relay K6 is connected to the injection valve stop light RD6. The normally open contact of relay K7 is connected to the No. 1 descaling pump inlet pressure over-high alarm light HL1. The normally open contact of relay K8 is connected to the No. 1... The following alarms are connected: HL2 (low inlet pressure alarm for pump #1), HL3 (high inlet pressure alarm for pump #2), HL4 (low inlet pressure alarm for pump #2), HL5 (thermal protection alarm for pump #1), HL6 (thermal protection alarm for pump #2), HL7 (billet arrival indicator), and HA (system fault buzzer alarm). The normally open contact of relay K15 is connected to the control terminal of the circulation valve, the normally open contact of relay K16 is connected to the control terminal of the injection valve, the normally open contacts of relays K17-K19 are respectively connected to the start, stop and standby terminals of the multi-function input terminal of inverter No. 1, the normally open contacts of relays K20-K22 are respectively connected to the start, stop and standby terminals of the multi-function input terminal of inverter No. 2, the normally open contact of relay K23 is connected to the coil of contactor KM1, and the normally open contact of relay K24 is connected to the coil of contactor KM2, thereby controlling the operation of oil pump motor No. 1 and oil pump motor No. 2.

[0028] See Figure 1-2The heating furnace sequential control PLC includes a power supply module, a CPU module, a digital input module, and a digital output module. The power supply module supplies power to the CPU module. The first four channels of the heating furnace sequential control PLC's digital input module are respectively connected to the normally open contacts of relays K1-K4, feeding back the start and stop signals of oil pumps No. 1 and No. 2 to the heating furnace sequential control PLC. The first eight channels of the heating furnace sequential control PLC's digital output module are respectively connected to relays KA1-KA6 and 14KA3-14KA. 4. The normally open contacts of relays KA1-KA6 and 14KA3-14KA4 are respectively connected in parallel with the No. 1 descaling pump motor start button SB1, No. 1 descaling pump motor stop button SD1, No. 2 descaling pump motor start button SB3, No. 2 descaling pump motor stop button SD3, No. 1 oil pump motor start button SB2, No. 1 oil pump motor stop button SD2, No. 2 oil pump motor start button SB4, and No. 2 oil pump motor stop button SD4, and are connected to the first 8 channels of the digital input module of the water descaling PLC.

[0029] See Figure 8-9 The three-phase power supply is connected to circuit breakers QF1 and QF2. The power input terminal of the inverter for motor No. 1 of the descaling pump is connected in series with reactor 1L and circuit breaker QF1, and communicates with the water descaling PLC through its communication port. The +24V, Y1, and Y2 terminals of the inverter for motor No. 1 of the descaling pump are connected to the coils of relays KA1 and KA2. The power input terminal of the inverter for motor No. 2 of the descaling pump is connected in series with reactor 2L and circuit breaker QF2, and communicates with the water descaling PLC through its communication port. The +24V, Y1, and Y2 terminals of the inverter for motor No. 2 of the descaling pump are connected to the coils of relays KA13 and KA4.

[0030] See Figure 10 The three-phase power supply is connected to circuit breakers QF11 and QF12. The power input terminal of oil pump motor No. 1 is connected in series with thermal relay FR1, normally open contact of contactor KM1, and circuit breaker QF11. The power input terminal of oil pump motor No. 2 is connected in series with thermal relay FR2, normally open contact of contactor KM2, and circuit breaker QF12.

[0031] Working principle: Automatic or manual operation is selected via the local operation button. When manual operation is selected, the water descaling control is local control. The local operation button controls the start and stop of motors No. 1 and No. 2 of the descaling pump, as well as oil pumps No. 1 and No. 2. It also controls the opening and closing of the circulation valve, the system emergency stop, and the clearing of alarms. The detection switch detects whether the oil pump pressure is too low or too high, whether the billet is in place, and whether the injection valve and circulation valve are in the correct opening and closing position. These input signals are output as control commands through the water descaling PLC to achieve local control of the water descaling motor, frequency converter, oil pump, and other equipment.

[0032] When automatic mode is selected, the host computer of the heating furnace selects remote mode and issues an automatic control command. The digital output module of the heating furnace sequential control PLC automatically outputs start and stop commands for the descaling motor and oil pump, and sends the commands to the digital input module of the water descaling PLC. Then, the output module of the water descaling PLC outputs control commands to realize the automatic remote control of equipment such as water descaling motor, frequency converter, and oil pump.

[0033] Locally, control parameters can also be input via a touchscreen and sent to the water descaling PLC via a DP coupler.

[0034] The billet arrival detector uses a hot metal detector to detect the signal of the billet entering the descaling area, triggering the circulation valve to close and the frequency converter to switch to high frequency mode, and starting high-pressure water jetting.

[0035] The circulation valve controls the water circulation path. The circulation valve is open when the billet has not entered the system to maintain internal circulation. The circulation valve is closed when the billet arrives and the system switches to high-pressure injection mode.

[0036] The above embodiments are implemented based on the technical solution of this utility model, providing detailed implementation methods and specific operation processes. However, the protection scope of this utility model is not limited to the above embodiments. Unless otherwise specified, the methods used in the above embodiments are conventional methods.

Claims

1. A PLC-based water descaling control system, characterized in that, The system includes a heating furnace host computer, a heating furnace sequential control PLC, a water descaling PLC, an oil pump motor, a frequency converter, indicator lights, local operation buttons, a circulation valve, a jet valve, a pressure transmitter, a detection switch, and a descaling pump motor. The heating furnace host computer is connected to the heating furnace sequential control PLC via optical fiber. The heating furnace sequential control PLC is connected to the water descaling PLC via cable. The output terminal of the water descaling PLC is connected to the frequency converter, and the output terminal of the frequency converter is connected to the descaling pump motor. The multi-function input terminal of the frequency converter is connected to the digital output terminal and the oil pump motor input terminal of the water descaling PLC. The pressure transmitter is connected to the analog input terminal of the water descaling PLC. The local operation buttons are connected to the digital input terminal of the water descaling PLC. The indicator lights, circulation valve, and jet valve are connected to the digital output terminal of the water descaling PLC. The detection switches include a pump set oil circuit pressure switch, a circulation valve open position proximity switch, a circulation valve close position proximity switch, a billet arrival detector, an injection valve open position proximity switch, and an injection valve close position proximity switch. The pump set oil circuit pressure switch, circulation valve open position proximity switch, circulation valve close position proximity switch, billet arrival detector, injection valve open position proximity switch, and injection valve close position proximity switch are connected to the digital input terminal of the water descaling PLC.

2. The PLC-based water descaling control system according to claim 1, characterized in that, It also includes a touch screen and a DP coupler. The touch screen is connected to the DP coupler via a PROFIBUS-DP communication cable, and the DP coupler is connected to the water descaling PLC via a PROFIBUS-DP communication cable.

3. The PLC-based water descaling control system according to claim 1, characterized in that, The heating furnace sequential control PLC includes a power supply module, a CPU module, a digital input module, and a digital output module. The power supply module supplies power to the CPU module. The input terminals of the digital input module are connected to the output terminals of the water descaling PLC and are used to display the start and stop of the oil pump on the heating furnace sequential control PLC. The output terminals of the digital output module are connected to the digital input terminals of the water descaling PLC and are used to send the remote start and stop signals of the water descaling PLC to the water descaling PLC.

4. The PLC-based water descaling control system according to claim 1, characterized in that, The local operation buttons include a descaling pump motor start button, a descaling pump motor stop button, an oil pump motor start button, an oil pump motor stop button, a circulation valve open button, a circulation valve close button, a system manual / automatic switch button, a system emergency stop button, and an alarm clear button.

5. The PLC-based water descaling control system according to claim 1, characterized in that, The indicator lights include a descaling pump motor running light, a descaling pump motor stopping light, an oil pump motor running light, an oil pump motor stopping light, a circulation valve running light, a circulation valve stopping light, an injection valve running light, an injection valve stopping light, a descaling pump inlet pressure too high alarm light, a descaling pump inlet pressure too low alarm light, an oil pump thermal protection alarm light, a billet arrival indicator light, and a system fault buzzer alarm.

6. The PLC-based water descaling control system according to claim 3, characterized in that, The water descaling PLC includes a power supply module, a CPU module, an analog input module, a digital input module, and a digital output module. The power supply module supplies power to the CPU module. The analog input module is connected to the pressure transmitter. The digital input module is connected to the local operation button and the detection switch. The digital output module is connected to the indicator light, the circulation valve, the injection valve, the frequency converter, and the oil pump motor.

7. A PLC-based water descaling control system according to claim 6, characterized in that, It also includes relays. The output terminals of the heating furnace sequential control PLC digital output module are electrically connected to the digital input terminals of the water descaling PLC through relays. The digital output module of the water descaling PLC is electrically connected to indicator lights, circulation valves, injection valves, frequency converters and oil pump motors through relays.

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