A PLC-based constant-pressure air blowing system for sawing line in finishing plant

Abstract

The utility model relates to a blowing control technical field especially, relates to a kind of finishing workshop saw cut line compressed air constant pressure blowing system based on PLC, including compressed air tank, electric actuator, spray head, blowing pipeline, photoelectric opposite radiation switch, compression motor, frequency converter, ac measurement loop, compression motor control loop and PLC control system, the opposite radiation switch is set in finishing workshop saw cut line transport roller and saw cut roller junction, the blowing pipeline is connected to compressed air tank, spray head is set in blowing pipeline gas outlet end, and it is set in the position that transport roller starting point directly above can be carried out blowing to rolled piece, electric actuator is set on blowing pipeline and is connected to PLC control system output end;The utility model has realized the full blowing of rolled piece on finishing workshop saw cut line, and timely remove the cooling liquid and the iron filings of rolled piece surface after sawing, the constant of the pressure in blowing pipeline is proved, and the effect of blowing is ensured.

Description

Technical Field

[0001] This utility model relates to the field of purging control technology, and in particular to a PLC-based compressed air constant pressure purging system for sawing lines in finishing workshops. Background Technology

[0002] In the steel rolling process, the rolled parts enter the sawing line in the finishing workshop for cut to length. During sawing, coolant from the saw blade and sawdust generated during the sawing process remain on the surface of the rolled parts. After sawing, the rolled parts are transported to the stacking rack via conveyor rollers for stacking before leaving the factory. Because the coolant that remains for a long time can corrode the surface of the rolled parts, and the large amount of sawdust can also affect the appearance of the product, the quality of the product will be greatly reduced, affecting subsequent delivery and acceptance. Therefore, timely removal of coolant and residual sawdust from the surface of the finished rolled parts after sawing has become a crucial part of product quality control. Utility Model Content

[0003] This invention provides a PLC-based compressed air constant pressure purging system for a finishing workshop sawing line, which realizes full purging of the rolled parts on the finishing workshop sawing line, timely removes coolant and residual iron filings from the surface of the finished rolled parts after sawing, ensures constant pressure in the purging pipeline, and ensures the purging effect.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A PLC-based compressed air constant pressure purging system for a sawing line in a finishing workshop includes a compressed air tank, an electric actuator valve, a nozzle, a purging pipe, a photoelectric photoelectric switch, a compressor motor, a frequency converter, an AC measurement circuit, a compressor motor control circuit, and a PLC control system. The photoelectric switch is located at the junction of the transport roller and the sawing roller in the finishing workshop sawing line. The purging pipe is connected to the compressed air tank. The nozzle is located at the air outlet of the purging pipe and is positioned directly above the starting point of the transport roller to purge the rolled workpiece. The electric actuator valve is located on the purging pipe and connected to the output of the PLC control system. The compressor motor control circuit includes a manual / automatic selection button, a stop button, a start button, relays KA1, KA2, K1, K2, K3, and K4, a running indicator light, and a fault indicator light. The manual / automatic selection button is connected to the normally closed contact of relay KA1 and the stop button SB1. The normally closed contact of relay KA1 is connected to a parallel circuit of the normally open contact of relay KA2 and the normally open contact of relay K1. The parallel circuit of the normally open contact of relay KA2 and the normally open contact of relay K1 is connected to the coil of relay K1. The stop button SB1 is connected to a parallel circuit of the normally open contact of relay K2 and the start button SB2. The parallel circuit of the normally open contact of relay K2 and the start button SB2 is connected to the coil of relay K2. The output terminals of coil 1 and relay K2 are connected to the normally closed contact of relay K4. The inverter's running signal output terminal is connected to relay K3 coil, and the inverter's fault signal output terminal is connected to relay K4 coil. The normally open contact of relay K3 is connected to the running indicator light, and the normally open contact of relay K4 is connected to the fault indicator light. The coils of relays KA1 to KA4 are connected to the digital output terminals of the PLC control system. Relays K3 to K4, K7 to K8, and the photoelectric photoelectric switch are connected to the digital input terminals of the PLC control system. The normally open contact of relay K1 is connected to the inverter's automatic start signal input terminal, and the normally open contact of relay K2 is connected to the inverter's manual start signal input terminal. The inverter's frequency setpoint terminal is connected to the analog output terminal of the PLC control system.

[0005] Furthermore, the compressor motor is configured with two units, the frequency converter is configured with two units, and the control loop is configured with two units, with one control loop connected to one frequency converter and one frequency converter connected to one compressor motor.

[0006] Furthermore, the PLC control system includes a power supply module, a CPU module, a digital input module, a digital output module, an analog input module, and an analog output module.

[0007] Furthermore, it also includes a pressure transmitter, which is installed on the purge pipe between the electric actuator valve and the compressed air tank, and the pressure transmitter is connected to the input terminal of the analog input module.

[0008] Furthermore, the photoelectric through-beam switch includes a photoelectric through-beam switch transmitter and a photoelectric through-beam switch receiver, which are respectively located at both ends of the junction of the transport roller conveyor and the sawing roller conveyor in the finishing workshop.

[0009] Furthermore, the inverter's model number is GD270-160-4.

[0010] Compared with the prior art, the beneficial effects of this utility model are: 1) The manual or automatic selection control of the compressor motor is realized through the compressor motor control circuit, frequency converter and PLC control system. The operation and faults of the motor are fed back and monitored in real time to ensure the stable operation of the compressor motor, thereby ensuring the stable blowing of the rolled parts on the sawing line of the finishing workshop. 2) A frequency converter is used to achieve energy saving and stable operation of the compressor motor; 3) By setting up a photoelectric beam switch, the workpiece is purged from the moment it enters the transport pipeline. The purging of the workpiece is precisely controlled by the nozzle, purging pipeline and electric actuator valve. Purging is carried out when it is needed and stopped when it is not needed, so as to remove the coolant and residual iron filings on the surface of the finished workpiece after sawing in a timely manner. 4) The pressure inside the purging pipeline is kept constant by real-time monitoring of the pressure transmitter and control by the PLC control system, thus ensuring the purging effect. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the purging structure of this utility model.

[0012] Figure 2 This is a wiring diagram of the frequency converter GD1 described in this embodiment of the utility model.

[0013] Figure 3 This is a wiring diagram of the control circuit of the compressor motor M1 described in this embodiment of the utility model.

[0014] Figure 4 This is a wiring diagram of the frequency converter GD2 described in this embodiment of the utility model.

[0015] Figure 5 This is a wiring diagram of the control circuit of the compressor motor M2 according to an embodiment of this utility model. Figure 6 This is a wiring diagram of the digital input module described in an embodiment of this utility model.

[0016] Figure 7 This is a wiring diagram of the digital output module described in an embodiment of this utility model.

[0017] Figure 8 This is a wiring diagram of the analog input module described in an embodiment of this utility model.

[0018] Figure 9 This is a schematic diagram of the analog output wiring according to an embodiment of the present invention.

[0019] In the diagram: 1. Compressed air tank; 2. Pressure transmitter; 3. Purge pipe; 4. Electric actuator valve; 5. Nozzle; 6. Photoelectric beam switch receiver; 7. Photoelectric beam switch transmitter; 8. Sawing roller conveyor; 9. Conveyor roller conveyor; 10. Rolled workpiece. Detailed Implementation

[0020] 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 compressed air constant pressure purging system for a sawing line in a finishing workshop, comprising purging equipment, compressed air tank 1, electric actuator valve 4, nozzle 5, purging pipeline 3, photoelectric photoelectric switch, pressure transmitter 2, compressor motor, frequency converter, compressor motor control circuit, and PLC control system.

[0021] See Figure 1 The photoelectric beam switch includes a photoelectric beam switch transmitter 7 and a photoelectric beam switch receiver 6. The photoelectric beam switch transmitter 7 and the photoelectric beam switch receiver 6 are respectively located at the two ends of the junction of the conveyor roller 9 and the sawing roller 8 of the finishing workshop sawing line. The purging pipe 3 is connected to the compressed air tank 1. The nozzle 5 is located at the air outlet of the purging pipe 3 and is located at a position directly above the starting point of the conveyor roller 9 that can purge the rolled piece 10. The electric actuator valve 4 is located on the purging pipe 3. The pressure transmitter is located on the purging pipe 3 between the electric actuator valve 4 and the compressed air tank 1.

[0022] The PLC control system includes a power supply module, a CPU module, a digital input module, a digital output module, an analog input module, and an analog output module. The power supply module supplies power to the CPU module. The PLC control system uses a Siemens ET200SP series PLC.

[0023] The compressor motor is configured with two units, the frequency converter is configured with two units, and the control loop is configured with two units. One control loop is connected to one frequency converter, and one frequency converter is connected to one compressor motor. See Figure 2-9For the first compressor motor GD1, its corresponding compressor motor control circuit includes a manual / automatic selection button SA, a stop button SB1, a start button SB2, relays KA1, KA2, K1, K2, K3, and K4, a running indicator light HG, and a fault indicator light HY. The manual / automatic selection button SA is connected to the normally closed contact of relay KA1 and the stop button SB1. The normally closed contact of relay KA1 is connected to the parallel circuit of the normally open contact of relay KA2 and the normally open contact of relay K1. The parallel circuit of the normally open contact of relay KA2 and the normally open contact of relay K1 is connected to the coil of relay K1. The stop button SB1 is connected to the parallel circuit of the normally open contact of relay K2 and the start button SB2. The parallel circuit of the normally open contact of relay K2 and the start button SB2 is connected to the coil of relay K2. The output terminals of the coils of relays K1 and K2 are both connected to the relay K4. The normally closed contact of relay 4, the inverter's running signal output terminals R01-1A and R01-1C are connected to the coil of relay K3, the inverter's fault signal output terminal is connected to the coil of relay K4, the normally open contact of relay K3 is connected to the running indicator HG, the normally open contact of relay K4 is connected to the fault indicator HY, the coils of relays KA1 to KA4 and the coil of electric actuator valve 4 are connected to the output terminal of the digital output module of the PLC control system, relays K3 to K4, K7 to K8 and photoelectric photoelectric switch are connected to the input terminal of the digital input module of the PLC control system, the normally open contact of relay K1 is connected to the inverter's automatic start signal input terminal, the normally open contact of relay K2 is connected to the inverter's manual start signal input terminal, the inverter's frequency setpoint terminals AI1 and GND are connected to the output terminal of the PLC control system's analog output module, and the pressure transmitter 2 is electrically connected to the input terminal of the analog input module through an isolator; For the second compressor motor GD2, the connection method and control principle of its corresponding compressor motor control circuit are the same as those of compressor motor GD1.

[0024] Working Principle: A photoelectric photoelectric switch for material detection is installed at the interface between the sawing roller conveyor 8 and the transport roller conveyor 9 after sawing. After sawing, the sawing platform descends, and the cut-length rolled piece 10 falls onto the sawing roller conveyor 8. The sawing roller conveyor 8 and the transport roller conveyor 9 start operating simultaneously. When the head of the sawn rolled piece 10 passes through the interface between the sawing roller conveyor 8 and the transport roller conveyor 9, the material detection switch detects the passing of the head of the rolled piece 10. At this time, the electric actuator valve 4 of the purging system is opened, and a large amount of compressed air is blown onto the surface of the rolled piece 10, blowing away the coolant and surface iron filings. When the tail of the rolled piece 10 passes through the material detection switch, the valve of the purging system is closed, and the operation stops. To ensure the pressure stability of the entire purging system, a pressure transmitter 2 is installed in the pipeline. The frequency of the compressor motor is adjusted by setting and feedback pressure through a PLC to ensure constant pressure in the pipeline and ensure the purging effect. The compressor motors are used in a one-in-one standby configuration, which also ensures the stable operation of the entire system.

[0025] 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 compressed air constant pressure purging system for a sawing line in a finishing workshop, characterized in that, The system includes a purging device, a compressed air tank, an electric actuator valve, a nozzle, a purging pipe, a photoelectric photoelectric switch, a compressor motor, a frequency converter, a compressor motor control circuit, and a PLC control system. The photoelectric switch is located at the junction of the transport roller conveyor and the sawing roller conveyor in the finishing workshop. The purging pipe is connected to the compressed air tank. The nozzle is located at the air outlet of the purging pipe and is positioned directly above the starting point of the transport roller conveyor to purge the rolled workpiece. The electric actuator valve is located on the purging pipe and connected to the output of the PLC control system. The compressor motor control circuit includes a manual / automatic selection button, a stop button, a start button, relays KA1, KA2, K1, K2, K3, and K4, a running indicator light, and a fault indicator light. The manual / automatic selection button is connected to the normally closed contact of relay KA1 and the stop button SB1. The normally closed contact of relay KA1 is connected to a parallel circuit of the normally open contact of relay KA2 and the normally open contact of relay K1. The parallel circuit of the normally open contact of relay KA2 and the normally open contact of relay K1 is connected to the coil of relay K1. The stop button SB1 is connected to a parallel circuit of the normally open contact of relay K2 and the start button SB2. The parallel circuit of the normally open contact of relay K2 and the start button SB2 is connected to the coil of relay K2. The output terminals of coil 1 and relay K2 are connected to the normally closed contact of relay K4. The inverter's running signal output terminal is connected to relay K3 coil, and the inverter's fault signal output terminal is connected to relay K4 coil. The normally open contact of relay K3 is connected to the running indicator light, and the normally open contact of relay K4 is connected to the fault indicator light. The coils of relays KA1 to KA4 are connected to the digital output terminals of the PLC control system. Relays K3 to K4, K7 to K8, and the photoelectric photoelectric switch are connected to the digital input terminals of the PLC control system. The normally open contact of relay K1 is connected to the inverter's automatic start signal input terminal, and the normally open contact of relay K2 is connected to the inverter's manual start signal input terminal. The inverter's frequency setpoint terminal is connected to the analog output terminal of the PLC control system.

2. The PLC-based compressed air constant pressure purging system for a finishing workshop sawing line according to claim 1, characterized in that, The compressor motor is configured with two units, the frequency converter is configured with two units, and the control loop is configured with two units, one control loop connected to one frequency converter and one frequency converter connected to one compressor motor.

3. The PLC-based compressed air constant pressure purging system for a finishing workshop sawing line according to claim 1, characterized in that, The PLC control system includes a power supply module, a CPU module, a digital input module, a digital output module, an analog input module, and an analog output module.

4. A PLC-based compressed air constant pressure purging system for a finishing workshop sawing line according to claim 3, characterized in that, It also includes a pressure transmitter, which is installed on the purge pipe between the electric actuator valve and the compressed air tank, and the pressure transmitter is connected to the input terminal of the analog input module.

5. A PLC-based compressed air constant pressure purging system for a finishing workshop sawing line according to claim 1, characterized in that, The photoelectric beam switch includes a photoelectric beam switch transmitter and a photoelectric beam switch receiver, which are respectively located at both ends of the junction of the conveyor roller and the sawing roller in the finishing workshop.

6. A PLC-based compressed air constant pressure purging system for a finishing workshop sawing line according to claim 1, characterized in that, The inverter model is GD270-160-4.

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