Double-fan exhaust air exhaust control circuit

Abstract

This utility model relates to a dual-fan exhaust gas control circuit, comprising: a power supply, circuit breaker one, circuit breaker two, circuit breaker three, frequency converter one, frequency converter two, fan one, fan two, a switching power supply, and a PLC controller. Frequency converter one is electrically connected to fan one and is used to control the speed of fan one. Frequency converter two is electrically connected to fan two and is used to control the speed of fan two. The power input terminal of the switching power supply is connected to the power supply, and the output terminal of the switching power supply is connected to the PLC controller to provide power. The dual-fan exhaust gas control circuit of this utility model achieves intelligent control for automatic switching between two exhaust fans (one in use and one in standby) in case of failure, timed switching, and automatic simultaneous start of both exhaust fans for forced exhaust in emergencies. It can detect signals through an air volume sensor to control the two frequency converters to work together, achieving the effect of maintaining a basically constant exhaust volume during the switching process.

Description

Technical Field

[0001] This utility model relates to the field of automation control technology, and in particular to a dual-fan exhaust gas control circuit. Background Technology

[0002] In some chemical and biological laboratories and hazardous waste warehouses, where hazardous waste gases are discharged, exhaust fan systems are installed. Currently, most exhaust fan systems use single exhaust fans for ventilation. Even those that use dual exhaust fans (one for use and one for backup) still require manual switching to start the corresponding fan. In particular, the exhaust air volume can change significantly during the switching process, affecting normal air supply and exhaust, indicating a low level of intelligence.

[0003] The current control method cannot achieve intelligent control such as automatic fault switching, timed switching, and automatic simultaneous start-up of two fans for forced ventilation in emergency situations. In particular, it cannot achieve the effect of constant air volume ventilation. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is to overcome the problem that the existing technology of dual-row fans cannot achieve reasonable intelligent automatic switching.

[0005] To solve the above-mentioned technical problems, this utility model provides a dual-fan exhaust gas control circuit, including: a power supply, a circuit breaker 1, a circuit breaker 2, a circuit breaker 3, a frequency converter 1, a frequency converter 2, a fan 1, a fan 2, a switching power supply, and a PLC controller. The power supply is connected to circuit breaker 1 and then splits into two circuits to supply power to circuit breaker 1 and circuit breaker 2 respectively. Circuit breaker 1 is used to connect or disconnect the power supply circuit of frequency converter 1, and circuit breaker 2 is used to connect or disconnect the power supply circuit of frequency converter 2. Frequency converter 1 is electrically connected to fan 1 and is used to control the speed of fan 1. Frequency converter 2 is electrically connected to fan 2 and is used to control the speed of fan 2. The power input terminal of the switching power supply is connected to the power supply, and the output terminal of the switching power supply is connected to the PLC controller to provide power. This utility model discloses a dual-fan exhaust gas control circuit. An external three-phase power supply is connected to the main circuit breaker Q1 of the control cabinet. Then, two 380VAC three-phase power supplies are split from the main circuit breaker Q1 to power two circuit breakers Q2 to Q3. Q2 is the power supply circuit for the first frequency converter, and Q3 is the power supply circuit for the second frequency converter. A live wire is connected from the L1 phase of the main circuit breaker Q1 to terminal 1 of fuses F1 and F2. Terminal 2 of fuse F1 is connected to the L terminal of the control cabinet cooling fan; terminal 2 of fuse F2 is connected to the L input terminal of the switching power supply. Two neutral wires are connected from the neutral terminal to the N terminal of the control cabinet cooling fan and the N terminal of the switching power supply, respectively. The two fans are controlled by frequency converters. Start / stop operation buttons for the two fans are installed in the local control cabinet and both inside and outside the laboratory or hazardous waste warehouse.

[0006] In one embodiment of this utility model, the power supply is a three-phase power supply, and the switching power supply is a 24V switching power supply.

[0007] In one embodiment of this utility model, the control circuit further includes a fuse and a cooling fan. A live wire is connected to the L1 phase of the circuit breaker to the first terminal of the fuse, and the second terminal of the fuse is connected to the L input terminal of the cooling fan. The neutral wire of the circuit breaker is connected to the N terminal of the cooling fan. The cooling fan is used for heat dissipation of the control cabinet where the control circuit is located.

[0008] In one embodiment of this utility model, the control circuit further includes a second fuse. A live wire is connected from the L1 phase of the first circuit breaker to the first terminal of the second fuse. The second terminal of the second fuse is connected to the L input terminal of the switching power supply. The neutral wire of the first circuit breaker is connected to the N terminal of the switching power supply.

[0009] In one embodiment of this utility model, the on / off ports of frequency converter one and frequency converter two are both 485 communication ports, and the 485A and 485B ports of frequency converter one are respectively connected to the 485A and 485B ports of frequency converter two.

[0010] In one embodiment of this utility model, the control circuit further includes several buttons, one end of which is connected to the 24+ of the switching power supply, and the other end of which is connected to the input terminal of the PLC controller.

[0011] In one embodiment of this utility model, the air outlet of the first fan is provided with a solenoid valve one, the air outlet of the second fan is provided with a solenoid valve two, the output terminal of the PLC controller is connected to one end of the coil of the first solenoid valve, the other end of the coil of the first solenoid valve is connected to the 24- of the switching power supply, the output terminal of the PLC controller is connected to one end of the coil of the second solenoid valve, and the other end of the coil of the second solenoid valve is connected to the 24- of the switching power supply.

[0012] In one embodiment of this utility model, the control circuit further includes several indicator lights, one end of which is connected to the output terminal of the PLC controller, and the other end of which is connected to the 24- of the switching power supply.

[0013] In one embodiment of this utility model, the control circuit further includes a buzzer, one end of which is connected to the output terminal of the PLC controller, and the other end of which is connected to the 24-pin switch power supply.

[0014] In one embodiment of this utility model, the PLC controller is model S7-200SMART, and the 24+ and 24- terminals of the switching power supply are respectively connected to the L and M terminals of the PLC controller.

[0015] Compared with the prior art, the above-mentioned technical solution of this utility model has the following beneficial effects:

[0016] This utility model describes a dual-fan exhaust gas control circuit that achieves intelligent control by automatically switching between two exhaust fans (one in operation and one on standby) in case of failure, timed switching, and automatic simultaneous activation of both exhaust fans for forced exhaust in emergencies. It employs frequency conversion control with an airflow sensor added to the exhaust duct. During operation, the airflow measurement value controls the frequency converter output, maintaining a constant exhaust volume. Specifically, during switching, the airflow sensor detects signals and controls the two frequency converters to work collaboratively, maintaining a essentially constant exhaust volume throughout the process. Furthermore, a pneumatic damper is added after each fan, characterized by rapid response and extremely short opening / closing times, making it particularly suitable for environments requiring quick response. Attached Figure Description

[0017] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0018] Figure 1 The electrical principle of the dual-fan exhaust gas control circuit in the preferred embodiment of this utility model. Figure 1 ;

[0019] Figure 2 The electrical principle of the dual-fan exhaust gas control circuit in the preferred embodiment of this utility model. Figure 2 ;

[0020] Figure 3 The electrical principle of the dual-fan exhaust gas control circuit in the preferred embodiment of this utility model. Figure 3 .

[0021] Instruction manual diagram labeling: Power supply 1, Circuit breaker 1, Circuit breaker 2, Circuit breaker 3, Variable frequency drive 1, Variable frequency drive 2, Fan 1, Fan 2, Switching power supply 9, PLC controller 10, Fuse 1, Cooling fan 12, Fuse 2, Button 14, Solenoid valve 1, Solenoid valve 2, Indicator light 17, Buzzer 18, Emergency stop button 19, Touch screen 20. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0023] Reference Figure 1-3This utility model discloses a dual-fan exhaust gas control circuit, comprising: a power supply 1, a circuit breaker 2, a circuit breaker 3, a circuit breaker 4, a frequency converter 5, a frequency converter 6, a fan 7, a fan 8, a switching power supply 9, and a PLC controller 10. The power supply 1 is connected to circuit breaker 2 and then splits into two circuits, supplying power to circuit breaker 2 and circuit breaker 3 respectively. Circuit breaker 2 is used to connect or disconnect the power supply circuit of frequency converter 5, and circuit breaker 3 is used to connect or disconnect the power supply circuit of frequency converter 6. Frequency converter 5 is electrically connected to fan 7 and is used to control the speed of fan 7. Frequency converter 6 is electrically connected to fan 8 and is used to control the speed of fan 8. The power input terminal of the switching power supply 9 is connected to the power supply 1, and the output terminal of the switching power supply 9 is connected to the PLC controller 10 to provide power. The power supply 1 is a three-phase power supply, and the switching power supply 9 is a 24V switching power supply. When the fan is changed from fan 7 to fan 8, the PLC controller 10 outputs an electrical signal to regulate the two frequency converters. The frequency converter 5 regulates the fan 7 to decelerate slowly. At the same time, the PLC controller 10 regulates the fan 8 to accelerate slowly through the frequency converter 6. Under the action of the PLC controller 10, when one fan is decelerating, the other fan is accelerating. By coordinating the wind speeds of the two fans, the exhaust volume output by the two fans is kept constant.

[0024] The control circuit described above further includes a fuse 11 and a cooling fan 12. A live wire is connected to the L1 terminal of the circuit breaker 11, and the second terminal of the fuse 11 is connected to the L input terminal of the cooling fan 12. The neutral wire of the circuit breaker 12 is connected to the N terminal of the cooling fan 12. The cooling fan 12 is used for heat dissipation in the control cabinet where the control circuit is located. The control circuit also includes a fuse 13. A live wire is connected to the L1 terminal of the circuit breaker 13, and the second terminal of the fuse 13 is connected to the L input terminal of the switching power supply 9. The neutral wire of the circuit breaker 12 is connected to the N terminal of the switching power supply 9.

[0025] In the above circuit, the on / off ports of inverter 5 and inverter 6 are both 485 communication ports. The 485A and 485B ports of inverter 5 are connected to the 485A and 485B ports of inverter 6, respectively. Then, the 485A and 485B ports of inverter 6 are connected to terminals X22 and X23, respectively.

[0026] The control circuit described above further includes several buttons 14 and an emergency stop button 19. One end of each button 14 is connected to the 24+ pin of the switching power supply 9, and the other end of each button 14 is connected to the input terminal of the PLC controller 10. One end of each emergency stop button 19 is connected to the 24+ pin of the switching power supply 9, and the other end of each emergency stop button 19 is connected to the input terminal of the PLC controller 10. The emergency stop button 19 is used to urgently stop either fan 7 or fan 8.

[0027] In the above circuit, the air outlet of fan 7 is equipped with solenoid valve 15, the air outlet of fan 8 is equipped with solenoid valve 26, the output terminal of PLC controller 10 is connected to one end of the coil of solenoid valve 15, the other end of the coil of solenoid valve 15 is connected to 24- of switching power supply 9, the output terminal of PLC controller 10 is connected to one end of the coil of solenoid valve 26, and the other end of the coil of solenoid valve 26 is connected to 24- of switching power supply 9.

[0028] The control circuit described above also includes several indicator lights 17. One end of each indicator light 17 is connected to the output terminal of the PLC controller 10, and the other end of each indicator light 17 is connected to terminal 24 of the switching power supply 9. The indicator lights 17 are each set to a different color to indicate different operating states.

[0029] The control circuit described above also includes a buzzer 18, one end of which is connected to the output terminal of the PLC controller 10, and the other end of which is connected to the 24-pin terminal of the switching power supply 9.

[0030] The control circuit described above also includes a touchscreen 20, whose power supply terminals L and M are connected to terminals 24+ and 24- of the switching power supply 9, respectively. The network communication port of the PLC controller 10 is connected to the network communication port of the touchscreen 20 via a network cable.

[0031] The control circuit mainly consists of a PLC controller 10, relays, buttons, and indicator lights connected to the PLC controller 10. The PLC model for the control circuit is S7-200SMART, and pins 24+ and 24- of the switching power supply 9 are connected to the L and M terminals of the PLC controller 10, respectively.

[0032] The above-mentioned dual-fan exhaust gas control circuit is connected to the hazardous area gas sensor, air volume sensor and frequency converter control signal via RS485 communication. This connection method is simple to wire, has strong anti-interference ability, and at the same time greatly reduces the number of control modules, saves control costs and control cabinet space.

[0033] This utility model's dual-fan exhaust gas control circuit operates as follows: under normal circumstances, pressing the start button on either fan 7 (or fan 8) at the local control cabinet, indoors or outdoors, starts one fan. When the running fan reaches its set running time, it automatically switches to the other fan for alternating operation. During the switching process, the damper of the non-running fan is opened first, and the non-running fan is slowly started at low speed while the running fan is gradually decelerated. Throughout the switching process, the PLC controller 10 coordinates the acceleration and deceleration speeds of the two fans based on the airflow sensor installed at the exhaust vent, ensuring a relatively constant exhaust volume during the switching process. When the frequency of the decelerating fan drops to 0, its exhaust valve is quickly closed, completing the switching process.

[0034] When the system detects that the gas concentration in a hazardous area exceeds the set value, it automatically starts two fans (7) or one fan (8) to force ventilation. An alarm is also issued to indicate that the gas concentration in the area is too high. Once the gas concentration returns to normal, and after manual confirmation that the gas is normal and the reset button on the control cabinet is pressed, the system returns to normal operation.

[0035] When one of the fans fails during operation, an alarm is issued, and the system automatically switches to another working fan. During the switching process, because the failed fan is in an inertial stop state, the PLC controller 10 will quickly adjust the frequency of the normal fan during startup based on the detected air volume value to achieve a basically constant exhaust volume. When the frequency of the normal fan reaches the frequency required for the rated air volume, the air valve of the failed fan is closed, completing the fault switching process.

[0036] When the control system receives a signal indicating that the fire damper has activated, the system stops operating and triggers an alarm.

[0037] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A dual-fan exhaust air exhaust control circuit, characterized by, include: The system includes a power supply, circuit breaker 1, circuit breaker 2, circuit breaker 3, frequency converter 1, frequency converter 2, fan 1, fan 2, a switching power supply, and a PLC controller. The power supply is connected to circuit breaker 1 and then splits into two circuits, supplying power to circuit breaker 1 and circuit breaker 2 respectively. Circuit breaker 1 is used to connect or disconnect the power supply circuit of frequency converter 1, and circuit breaker 2 is used to connect or disconnect the power supply circuit of frequency converter 2. Frequency converter 1 is electrically connected to fan 1 and is used to control the speed of fan 1. Frequency converter 2 is electrically connected to fan 2 and is used to control the speed of fan 2. The power input terminal of the switching power supply is connected to the power supply, and the output terminal of the switching power supply is connected to the PLC controller to provide power.

2. The dual-fan exhaust air exhaust control circuit of claim 1, wherein: The power supply is a three-phase power supply, and the switching power supply is a 24V switching power supply.

3. The dual-fan exhaust air exhaust control circuit of claim 1, wherein: The control circuit also includes a fuse and a cooling fan. A live wire is connected to the L1 phase of the circuit breaker to the first terminal of the fuse. The second terminal of the fuse is connected to the L input terminal of the cooling fan. The neutral wire of the circuit breaker is connected to the N terminal of the cooling fan. The cooling fan is used for heat dissipation of the control cabinet where the control circuit is located.

4. The dual-fan exhaust air exhaust control circuit of claim 3, wherein: The control circuit also includes a second fuse. A live wire is connected from the L1 phase of the first circuit breaker to the first terminal of the second fuse. The second terminal of the second fuse is connected to the L input terminal of the switching power supply. The neutral wire of the first circuit breaker is connected to the N terminal of the switching power supply.

5. The dual-fan exhaust air exhaust control circuit of claim 1, wherein: The on / off ports of both inverter one and inverter two are 485 communication ports, and the 485A and 485B ports of inverter one are connected to the 485A and 485B ports of inverter two, respectively.

6. The dual-blower exhaust air exhaust control circuit of claim 2, wherein: The control circuit also includes several buttons, one end of which is connected to the 24+ of the switching power supply, and the other end of which is connected to the input terminal of the PLC controller.

7. The dual-fan exhaust gas control circuit according to claim 2, characterized in that: The air outlet of fan one is equipped with solenoid valve one, and the air outlet of fan two is equipped with solenoid valve two. The output terminal of the PLC controller is connected to one end of the coil of solenoid valve one, and the other end of the coil of solenoid valve one is connected to the 24- of the switching power supply. The output terminal of the PLC controller is connected to one end of the coil of solenoid valve two, and the other end of the coil of solenoid valve two is connected to the 24- of the switching power supply.

8. The dual-blower exhaust air exhaust control circuit of claim 2, wherein: The control circuit also includes several indicator lights, one end of which is connected to the output terminal of the PLC controller, and the other end of which is connected to the 24-pin switch power supply.

9. The dual-fan exhaust air exhaust control circuit of claim 8, wherein: The control circuit also includes a buzzer, one end of which is connected to the output terminal of the PLC controller, and the other end of which is connected to the 24-pin switch power supply.

10. The dual-blower exhaust air exhaust control circuit of claim 2, wherein: The PLC controller is model S7-200SMART, and the 24+ and 24- terminals of the switching power supply are respectively connected to the L and M terminals of the PLC controller.

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