Automatic control device for fans

Abstract

This utility model discloses an automatic control device for a fan, relating to the field of industrial fan control technology. It includes a detection element, a temperature controller, an intermediate relay, a changeover switch, and an AC contactor. The signal output terminal of the detection element is connected to the signal input terminal of the temperature controller, and the alarm output channel of the temperature controller is connected to the coil of the intermediate relay. The first output terminal of the changeover switch is connected to an automatic control circuit, and the normally open contact of the intermediate relay is connected in series in the automatic control circuit. The automatic control circuit is connected to the fan motor through the coil of the AC contactor. Compared with existing technologies, this utility model can solve the problem that existing axial flow fans in factories require operators to monitor ambient temperature and manually start and stop them on-site, resulting in wasted manpower and energy.

Description

Technical Field

[0001] This utility model relates to the field of industrial fan control technology, and in particular to an automatic fan control device. Background Technology

[0002] In industrial production enterprises such as metallurgy, machining, and chemicals, multiple axial flow fans are typically installed in the factory for environmental ventilation and equipment cooling. The operating status of these fans directly affects the production environment and energy consumption within the factory. Currently, the control of multiple axial flow fans in a factory generally adopts the traditional manual operation mode: operators need to conduct regular inspections in the factory, monitor the ambient temperature, and then judge whether to start or stop the fans and the number of fans to start or stop based on experience.

[0003] This control method has significant drawbacks: 1. High labor costs: Factory areas are usually large, and it takes a lot of time and energy for operators to check the temperature of the entire area and operate the fans. Especially in multi-shift production scenarios, it is necessary to continuously allocate dedicated personnel to be responsible for fan control, which greatly increases the company's labor costs.

[0004] 2. Delayed temperature monitoring: Manual inspections have time intervals, making it impossible to monitor the ambient temperature in real time. When the temperature rises suddenly, the failure to start the machine in time may lead to excessively high temperatures in the factory, affecting the normal operation of production equipment. When the temperature drops, if the machine is not stopped in time, the extra running fans will continue to consume electricity, resulting in serious energy waste.

[0005] 3. Low control precision: Operators rely solely on experience to determine the number of fans to start and stop, making it impossible to achieve precise "temperature segment-multiple fan combination" control based on temperature changes. For example, when the temperature rises slightly, starting a small number of fans may meet the demand, but due to experience deviations, too many fans may be started, further exacerbating energy waste.

[0006] While some existing fan control technologies attempt to incorporate automation, they are mostly designed for single fans or a fixed number of fan units. They cannot achieve flexible control by adjusting the combined operation of multiple fans according to temperature segments, and thus fail to address the core issues of high labor costs and energy waste. Therefore, there is an urgent need for a device that can achieve automated operation of multiple fans in controlled temperature segments, fundamentally replacing manual operation and reducing labor costs and energy consumption. Utility Model Content

[0007] The purpose of this invention is to provide an automatic control device for fans, which can solve the problem that existing axial flow fans in factories require operators to monitor the ambient temperature and manually start and stop them on-site, resulting in high manpower consumption and energy waste.

[0008] To solve the above problems, the technical solution adopted by this utility model is as follows: This automatic control device for a fan includes a detection element, a temperature controller, an intermediate relay, a changeover switch, and an AC contactor; the signal output terminal of the detection element is connected to the signal input terminal of the temperature controller, and the alarm output channel of the temperature controller is connected to the coil of the intermediate relay; the first output terminal of the changeover switch is connected to the automatic control circuit, the normally open contact of the intermediate relay is connected in series in the automatic control circuit, and the automatic control circuit is connected to the fan motor through the coil of the AC contactor.

[0009] A more specific technical solution than the above-mentioned technical solution could be: a thermal relay is provided between the coil of the AC contactor and the fan motor.

[0010] Furthermore, a low-voltage circuit breaker is provided between the temperature controller and the input power supply.

[0011] Furthermore, the second output terminal of the changeover switch is connected to the coil of the AC contactor via a manual control circuit. The manual control circuit includes a normally closed push-button switch and a normally open push-button switch. The normally closed push-button switch is located near the changeover switch, and the normally open push-button switch is located near the coil of the AC contactor.

[0012] Furthermore, a self-locking circuit is connected in parallel to both ends of the normally open push button switch, and the normally open contact of the AC contactor is connected in series in the self-locking circuit.

[0013] Furthermore, the normally closed contact of the intermediate relay is connected in series in the self-locking circuit.

[0014] Furthermore, the detection element is a thermistor.

[0015] By adopting the above technical solution, this utility model has the following beneficial effects compared with the prior art: 1. This utility model eliminates the need for manual temperature monitoring and fan operation, significantly reducing labor costs. Temperature is collected in real time through detection elements, and the temperature controller and intermediate relay automatically realize the combined operation of multiple fans in different temperature segments. There is no need for operators to regularly inspect and monitor the temperature or manually start and stop the fans on site, which can reduce the configuration of dedicated fan control personnel and significantly reduce the company's labor costs.

[0016] 2. Based on preset temperature thresholds, different combinations of fans can be automatically operated. Fewer fans are started when the temperature is low and more fans are started when the temperature is high, avoiding situations where "multiple fans are running even when the temperature is insufficient" or "fans are not started in time when the temperature is too high", thus reducing the increase in equipment energy consumption caused by excessively high temperature and the waste of electricity caused by excessively low temperature.

[0017] 3. This utility model supports "manual / automatic" switching. In automatic mode, precise temperature control can be achieved, while in manual mode, it can handle equipment maintenance or special working conditions. At the same time, it avoids circuit failure or motor overload damage through isolation by the normally closed contact of the intermediate relay, protection by the low-voltage circuit breaker and thermal relay. Attached Figure Description

[0018] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model; however, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0020] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] Figure 1 This is an electrical schematic diagram of the fan control system in a factory building. The factory building has 9 fans and 2 streetlights. Fans #1 to #4 and the 2 streetlights are all manually controlled, while fans #5 to #9 are controlled by both automatic and manual methods.

[0022] The automatic control device used for fans #5 to #9 includes a detection element, a temperature controller TC, intermediate relays KA1, KA2, and KA3, a changeover switch SA, and AC contactors KM5, KM6, KM7, KM8, and KM9. The signal output terminal of the detection element is connected to the signal input terminal of the temperature controller TC. One alarm output channel of the temperature controller TC is connected to the coils of intermediate relays KA1 and KA2, and the other alarm output channel is connected to the coil of intermediate relay KA3. The first input of the changeover switch SA... The output terminal is connected to 5 automatic control circuits. The two normally open contacts of intermediate relay KA1 are connected in series in the automatic control circuits of fan motors #5 and #6, respectively. The one normally open contact of intermediate relay KA2 is connected in series in the automatic control circuit of fan motor #7, and the two normally open contacts of intermediate relay KA3 are connected in series in the automatic control circuits of fan motors #8 and #9, respectively. The 5 automatic control circuits are connected to fan motors #5, #6, #7, #8, and #9 respectively through the coils of AC contactors KM5, KM6, KM7, KM8, and KM9.

[0023] Thermal relays FR5, FR6, FR7, FR8, and FR9 are respectively installed between the coils of the 5 AC contactors and the 5 fan motors; a low-voltage circuit breaker QF1 is installed between the temperature controller TC and the input power supply.

[0024] The second output terminal of the changeover switch SA is connected to the coils of AC contactors KM5, KM6, KM7, KM8, and KM9 through five manual control circuits. Each of the five manual control circuits is equipped with normally closed push-button switches SB9, SB11, SB13, SB15, and SB17 and normally open push-button switches SB10, SB12, SB14, SB16, and SB18. The normally closed push-button switches are located closer to the changeover switch SA, and the normally open push-button switches are located closer to the coils of the AC contactors.

[0025] Each of the five normally open push-button switches has a self-locking circuit connected in parallel at both ends. The normally open contacts of AC contactors KM5 and KM6 are connected in series with the two pairs of normally closed contacts of intermediate relay KA1 in the self-locking circuits of fan motors #5 and #6, respectively. The normally open contact of AC contactor KM7 is connected in series with the normally closed contact of intermediate relay KA2 in the self-locking circuit of fan motor #7. The normally open contacts of AC contactors KM8 and KM9 are connected in series with the self-locking circuits of fan motors #8 and #9. Each fan has a corresponding indicator light. One end of the indicator light is connected to the fan motor, and the other end is connected to the automatic control circuit, the manual control circuit, and the self-locking circuit.

[0026] The sensing element is a resistance temperature detector (RTD), and the temperature controller TC is a digital display temperature controller.

[0027] When the selector switch SA is switched to the first output terminal, the working principle of the above-mentioned automatic control device is as follows: the temperature controller TC has two alarm output channels. One alarm output channel has a temperature alarm value of 40℃, and the other alarm output channel has a temperature alarm value of 50℃. The temperature is divided into three temperature levels based on the two temperature alarm values. The temperature is below the two alarm values ​​and the fan is fixed in the first stage. The temperature is between the two alarm values ​​and the second stage. The temperature is above the two alarm values ​​and the third stage. Each time the temperature level increases, an additional set of fans is controlled to be turned on. When the temperature is below 40℃, KA1, KA2, and KA3 do not operate; only the fixed fans (1# to 4#) controlled manually run. When the temperature is above 40℃ but below 50℃, the coils of intermediate relays KA1 and KA2 are simultaneously energized. KA1's two normally open contacts close, and its two normally closed contacts open, energizing the coils of AC contactors KM5 and KM6. This powers and runs the motors of fans 5# and 6#. KA2's one normally open contact closes, and its one normally closed contact opens, energizing the coil of AC contactor KM7. The No. 7 fan motor is energized and operates together with the No. 5 and No. 6 fan motors. When the temperature exceeds 50℃, the coil of the intermediate relay KA3 is energized, its two normally open contacts close, and the coils of the AC contactors KM8 and KM9 are energized, so all five fan motors are energized and operate together. The normally closed contacts of the intermediate relays are set on the self-locking circuits of the No. 5, No. 6, and No. 7 fan motors to prevent the control circuits of different groups of fan motors from being connected through the self-locking circuit and failing to stop automatically in automatic control mode. The normally closed contacts of the intermediate relays open after being energized to effectively isolate the fan motors.

[0028] When the changeover switch SA is switched to the second output terminal, all five fans switch to manual control mode. Pressing the normally open push-button switches SB10, SB12, SB14, SB16, and SB18 energizes the coils of AC contactors KM5, KM6, KM7, KM8, and KM9, causing their normally open contacts to close and self-lock, ensuring stable operation of each fan motor. To shut down a fan, simply open the corresponding normally closed push-button switch.

[0029] The temperature controller can be set with different temperature alarm values ​​as needed to control the action of different intermediate relays. Then, the intermediate relays can be linked to control the operation of multiple fans simultaneously, thereby achieving the requirement of controlling the number of fans in operation by temperature segment.

[0030] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An automatic control device for a fan, characterized in that: The system includes a detection element, a temperature controller, an intermediate relay, a changeover switch, and an AC contactor. The signal output terminal of the detection element is connected to the signal input terminal of the temperature controller, and the alarm output channel of the temperature controller is connected to the coil of the intermediate relay. The first output terminal of the changeover switch is connected to an automatic control circuit, and the normally open contact of the intermediate relay is connected in series in the automatic control circuit. The automatic control circuit is connected to the fan motor through the coil of the AC contactor.

2. The automatic control device for a fan according to claim 1, characterized in that: A thermal relay is provided between the coil of the AC contactor and the fan motor.

3. The automatic control device for a fan according to claim 2, characterized in that: A low-voltage circuit breaker is provided between the temperature controller and the input power supply.

4. The automatic control device for a fan according to any one of claims 1 to 3, characterized in that: The second output terminal of the changeover switch is connected to the coil of the AC contactor via a manual control circuit. The manual control circuit includes a normally closed push-button switch and a normally open push-button switch. The normally closed push-button switch is located near the changeover switch, and the normally open push-button switch is located near the coil of the AC contactor.

5. The automatic control device for a fan according to claim 4, characterized in that: The normally open push button switch has a self-locking circuit connected in parallel at both ends, and the normally open contact of the AC contactor is connected in series in the self-locking circuit.

6. The automatic control device for a fan according to claim 5, characterized in that: The normally closed contact of the intermediate relay is connected in series in the self-locking circuit.

7. The automatic control device for a fan according to claim 6, characterized in that: The detection element is a resistance temperature detector (RTD).

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