Energy-saving device for industrial circulating water

Abstract

The utility model discloses an industrial circulating water energy -conserving device, include: cooling tower, cooling tower fan, water collecting pool, multiple temperature sensor, circulating water pipeline and controller, the cooling tower is equipped with the water inlet, the cooling tower fan sets up the cooling tower top, the cooling tower fan is suitable for the circulating water ventilation cooling in cooling tower, the water collecting pool sets up the cooling tower bottom, the water collecting pool is suitable for the collection and storage after cooling tower circulating water of cooling tower cooling fan, temperature sensor is along the height direction interval and is arranged in the water collecting pool, the circulating water pipeline includes water supply pipeline and backwater pipeline, water supply pipeline one end with water collecting pool intercommunication, the other end with the cooling water import intercommunication of external heat exchange equipment, backwater pipeline one end with the cooling water export intercommunication of external heat exchange equipment, the utility model discloses can through the accurate reflection water collecting pool temperature, realizes circulating water cooling energy -conserving.

Description

Technical Field

[0001] This utility model relates to the field of industrial circulating water treatment technology, and specifically to an energy-saving device for industrial circulating water. Background Technology

[0002] Currently, industrial circulating water systems suffer from low levels of industrial control due to limitations in their application scenarios and inherent conditions. Circulating water systems, especially those in steel mills and power plants, involve significant energy consumption, including water and electricity. These systems typically consist of numerous, dispersed individual units connected by pipelines. The monitoring points along these pipelines are often singular and primarily serve only for monitoring and display, without participating in control. Even when controlled via DCS, the equipment is only remotely started and stopped.

[0003] Industrial cooling towers typically use fans powered by fixed-frequency motors. These fans cannot adjust in time with seasonal climate changes, resulting in excessive airflow at low temperatures and wasting both electricity and evaporated water. Similarly, circulating water pumps are often fixed-frequency pumps, with head selections based on estimates and large margins during design. In actual use, as air temperature changes and water temperature decreases, the required cooling water volume at the equipment level reduces. However, the pump flow rate and head cannot be adjusted, directly leading to wasted electricity.

[0004] A search of existing technologies revealed Chinese patent CN213300897U, which discloses a circulating water cooling device. This device mainly consists of a circulating water tank, a cooling tower, a cooling fan, a water pan, a remote temperature detector, and a wet-bulb temperature detector. The device automatically controls the fan's operation by placing a remote temperature detector in the connection space between the cooling tower and the circulating water tank, and combining this with the wet-bulb temperature detector to monitor air humidity and temperature. Based on these temperature values, the operating frequency of the cooling fan is controlled. However, shortcomings remain: using only a single remote temperature detector makes it difficult to accurately reflect the true temperature distribution in the circulating water tank, especially in large industrial circulating water systems where the tank is deep and the water temperature varies in different areas; single-point temperature detection cannot provide a reliable basis for precise control. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide an industrial circulating water energy-saving device that can realize energy saving of circulating water cooling by accurately reflecting the temperature of the water collection pool.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is: an energy-saving device for industrial circulating water, comprising:

[0007] The cooling tower is equipped with a water inlet;

[0008] A cooling tower fan is disposed above the cooling tower and is adapted to ventilate and cool the circulating water inside the cooling tower.

[0009] A water collection tank is provided at the bottom of the cooling tower, and the water collection tank is adapted to collect and store the circulating water of the cooling tower after being cooled by the cooling tower fan;

[0010] Multiple temperature sensors are spaced apart along the height direction within the water collection tank;

[0011] The circulating water pipeline includes a water supply pipeline and a water return pipeline. One end of the water supply pipeline is connected to the water collection tank, and the other end is connected to the cooling water inlet of the external heat exchange equipment. One end of the water return pipeline is connected to the cooling water outlet of the external heat exchange equipment, and the other end is connected to the water inlet of the cooling tower.

[0012] The controller is electrically connected to the temperature sensor and the cooling tower fan respectively;

[0013] The controller is adapted to adjust the operating frequency of the cooling tower fan based on the average temperature value of the plurality of temperature sensors.

[0014] Furthermore, the temperature sensor is configured to be three, which are respectively located at the upper, middle and lower parts of the water collection tank. The controller is adapted to adjust the operating frequency of the cooling tower fan based on the average value detected by the three temperature sensors.

[0015] Furthermore, the controller also includes a delay component and a control component connected to each other. The delay component is adapted to control the control component. After the temperature value of the temperature sensor changes, the delay component delays the control of the cooling tower fan according to a preset delay time in the delay component.

[0016] Furthermore, the water supply pipeline includes:

[0017] A main water inlet pipeline, one end of which is connected to the water collection tank;

[0018] A main outlet water pipeline, one end of which is connected to the heat exchange equipment;

[0019] The first branch pipeline has one end connected to the other end of the main inlet pipeline and the other end connected to the other end of the main outlet pipeline. A first valve and a first circulating water pump are sequentially installed on the first branch pipeline along the water flow direction.

[0020] The second branch pipeline has one end connected to the other end of the main inlet pipeline and the other end connected to the other end of the main outlet pipeline. A second valve and a second circulating water pump are sequentially installed on the second branch pipeline along the water flow direction.

[0021] Furthermore, a pressure transmitter is installed on the return water pipeline, and the pressure transmitter is connected to the controller.

[0022] The controller is adapted to adjust the first circulating water pump or the second circulating water pump according to the detection value of the pressure transmitter.

[0023] Furthermore, the industrial circulating water energy-saving device also includes a bypass filter pipeline, which has an outlet end and an inlet end. The outlet end is connected to the main inlet pipeline, and the inlet end is connected to the main outlet pipeline. A filter is provided on the bypass filter pipeline.

[0024] Furthermore, a flow meter is installed on the main water outlet line, and the flow meter is connected to the controller.

[0025] Furthermore, the industrial circulating water energy-saving device also includes a dosing device pipeline, which has an inlet and an outlet. The inlet is connected to the water supply pipeline, and the outlet is connected to the water collection tank. A dosing device is installed on the dosing device pipeline.

[0026] Furthermore, the industrial circulating water energy-saving device also includes a conductivity meter, which is installed in the water collection tank and connected to the controller;

[0027] The controller is adapted to control the start and stop of the dosing device based on the conductivity value detected by the conductivity meter.

[0028] By adopting the above technical solution, this utility model has the following beneficial effects:

[0029] In this invention, multiple temperature sensors are spaced apart along the height of the water collection tank, enabling accurate detection of water temperature changes at different depths within the tank. The controller adjusts the operating status of the cooling tower fan based on the average temperature values ​​from the multiple sensors, solving the problem of inaccurate temperature detection in the circulating water leading to inaccurate control of the cooling tower fan. The supply water pipeline transports the cooled circulating water to external heat exchange equipment, while the return water pipeline returns the heat-exchanged circulating water to the cooling tower inlet, forming a loop.

[0030] In addition, the delay component works in conjunction with the control component to avoid frequent control of the cooling tower fan when the temperature changes; the pressure transmitter is installed on the return water pipeline to provide pressure feedback for the control of the circulating water pump; the filter in the bypass pipeline improves the water quality of the circulating water; the dosing device pipeline and dosing device realize dosing based on the conductivity meter.

[0031] In summary, this utility model effectively solves the technical problems of low control accuracy and serious energy waste in circulating water by using multi-point temperature detection, thus achieving water and electricity saving in the circulating water system. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the industrial circulating water energy-saving device of this utility model in Embodiment 1;

[0033] Figure 2 This is a schematic diagram of the industrial circulating water energy-saving device of this utility model in Embodiment 2. Detailed Implementation

[0034] 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.

[0035] Example 1: As Figure 1 As shown, an industrial circulating water energy-saving device includes:

[0036] Cooling tower 1, cooling tower 1 is equipped with a water inlet;

[0037] A cooling tower fan is installed above the cooling tower 1 and is suitable for ventilating and cooling the circulating water inside the cooling tower 1.

[0038] Water collection tank 3 is located at the bottom of cooling tower 1. Water collection tank 3 is suitable for collecting and storing the circulating water of cooling tower 1 after being cooled by cooling tower fan.

[0039] Multiple temperature sensors 5 are spaced apart along the height direction in the water collection tank 3;

[0040] The circulating water pipeline includes a water supply pipeline and a return water pipeline 10. One end of the water supply pipeline is connected to the water collection tank 3, and the other end is connected to the cooling water inlet of the external heat exchange equipment. One end of the return water pipeline 10 is connected to the cooling water outlet of the external heat exchange equipment, and the other end is connected to the water inlet of the cooling tower 1.

[0041] The controller is connected to temperature sensor 5 and cooling tower fan respectively;

[0042] The controller is adapted to adjust the operating frequency of the cooling tower fan based on the average temperature value of multiple temperature sensors 5.

[0043] In this embodiment, as Figure 1As shown, multiple temperature sensors 5 are distributed along the height of the water collection tank 3, collecting water temperature data at different depths sequentially from the bottom of the tank 3 upwards. Due to temperature stratification within the water collection tank 3, there is a difference between the upper and lower water temperatures. By placing temperature sensors 5 at different heights, the controller receives the detection signals from each sensor 5 and calculates the average value. This average value is used as the basis for frequency adjustment of the cooling tower fan, ensuring that the operating frequency of the cooling tower fan matches the actual water temperature within the water collection tank 3.

[0044] The controller is a DCS controller. The input terminals of the DCS controller are connected to the signal output terminals of each temperature sensor 5, and the output terminals are connected to the control terminal of the frequency converter controlling the cooling tower fan. The temperature sensors 5 transmit the temperature signals from the water collection tank 3 to the DCS controller. The DCS controller receives the temperature signals from each temperature sensor 5 and calculates the average value. Based on a preset temperature-frequency correspondence, it outputs a corresponding control signal to the frequency converter of the cooling tower fan. The frequency converter adjusts its output frequency according to the received control signal, thereby changing the speed of the cooling tower fan. For example, when the average temperature decreases, the DCS controller outputs a control signal with a reduced frequency, thus reducing the cooling tower fan speed; when the average temperature increases, the DCS controller outputs a control signal with a increased frequency, thus increasing the cooling tower fan speed.

[0045] In addition, the temperature adjustment scale value of the DCS controller in this embodiment is set to 0.5℃. The controller will only adjust the operating frequency of the cooling tower fan when the average temperature value changes by more than 0.5℃.

[0046] In some embodiments, the controller can also be a PLC. Besides connecting the controller to the cooling tower fan via a frequency converter, frequency regulation can also be achieved through a servo driver.

[0047] Specifically, such as Figure 1 As shown, there are three temperature sensors 5, which are respectively located at the top, middle and bottom of the water collection tank 3. The controller is adapted to adjust the operating frequency of the cooling tower fan according to the average value detected by the three temperature sensors 5.

[0048] In this embodiment, as Figure 1 As shown, three temperature sensors 5 are fixed at the upper, middle, and lower parts of the inner wall of the water collection tank 3, respectively. The upper temperature sensor 5 detects the temperature of the upper layer of water in the water collection tank 3, the middle temperature sensor 5 detects the temperature of the middle layer of water in the water collection tank 3, and the lower temperature sensor 5 detects the temperature of the bottom layer of water in the water collection tank 3. The controller receives the temperature signals transmitted by the three temperature sensors 5, performs an arithmetic average calculation on the three temperature values, and obtains the average temperature value of the circulating water in the water collection tank 3. This average temperature value is used as the basis for adjusting the operating frequency of the cooling tower fan.

[0049] In some embodiments, temperature sensors 5 may be configured as two, respectively located at the upper and lower parts of the water collection tank 3; or as four or more, evenly distributed along the height of the water collection tank 3. Temperature sensors 5 may be resistance temperature sensors.

[0050] Specifically, such as Figure 1 As shown, the controller also includes a delay component and a control component that are interconnected. The delay component is suitable for controlling the control component. After the temperature value of the temperature sensor 5 changes, the delay component delays and controls the cooling tower fan according to the preset delay time in the delay component.

[0051] In this embodiment, as Figure 1 As shown, after receiving the temperature signal from temperature sensor 5, the delay component counts the time according to a preset delay period. After the timer expires, it transmits the signal to the control component. The control component generates a frequency adjustment command based on the received signal and outputs it to the frequency converter of the cooling tower fan. By setting the delay component, frequent speed adjustments of the cooling tower fan caused by short-term temperature fluctuations are avoided.

[0052] In some embodiments, the delay time ranges from 30 seconds to 300 seconds, and can be specifically set to 60 seconds or 120 seconds. The delay time can be set according to the actual operating conditions of the circulating water system.

[0053] Specifically, such as Figure 1 As shown, the water supply pipeline includes:

[0054] The main water inlet pipe 11 is connected at one end to the water collection tank 3;

[0055] The main outlet water pipe 12 is connected to the heat exchange equipment at one end.

[0056] The first branch pipe 13 is connected at one end to the other end of the main inlet pipe 11 and at the other end of the main outlet pipe 12. The first branch pipe 13 is provided with a first valve 14 and a first circulating water pump 16 in sequence along the water flow direction.

[0057] The second branch pipe 18 is connected at one end to the other end of the main inlet pipe 11 and at the other end to the other end of the main outlet pipe 12. A second valve 19 and a second circulating water pump 21 are sequentially installed on the second branch pipe 18 along the water flow direction.

[0058] In this embodiment, as Figure 1As shown, the inlet end of the main inlet pipe 11 is located at the bottom of the water collection tank 3, drawing cooled circulating water from the bottom of the water collection tank 3. The outlet end of the main inlet pipe 11 is connected to the inlet ends of the first branch pipe 13 and the second branch pipe 18, respectively. The first branch pipe 13 and the second branch pipe 18 are arranged in parallel, and the outlet ends of both branch pipes are connected to the inlet end of the main outlet pipe 12, which transports the circulating water to the external heat exchange equipment. By setting up two parallel branch pipes, the standby function of the circulating water pump and the flow regulation function are realized.

[0059] The first valve 14 is located upstream of the first circulating water pump 16, and the second valve 19 is located upstream of the second circulating water pump 21. Both valves are butterfly valves. The first and second circulating water pumps 16 and 21 are centrifugal pumps. The inlets of the first and second circulating water pumps 16 and 21 are connected to the outlets of the first and second valves 14 and 19, respectively. The outlets of the first and second circulating water pumps 16 and 21 are connected to the main outlet pipeline 12, respectively. During normal operation, the valve and circulating water pump of one branch pipeline are opened, while the other branch pipeline remains as a backup. When a larger flow rate is required, both branch pipelines operate simultaneously. When one branch pipeline requires maintenance or repair, the other branch pipeline is switched to operation.

[0060] In addition, a flow meter is installed on the main outlet water line 12. The flow meter is connected to the controller. The controller makes a comprehensive judgment based on the flow rate value detected by the flow meter and the return water temperature, and adjusts the operating frequency of the cooling tower fan and the circulating water pump.

[0061] In some embodiments, the first circulating water pump 16 and the second circulating water pump 21 may also be axial flow pumps or mixed flow pumps.

[0062] Specifically, such as Figure 1 As shown, a pressure transmitter 23 is installed on the return water pipeline 10, and the pressure transmitter 23 is connected to the controller.

[0063] The controller is adapted to adjust the first circulating water pump 16 or the second circulating water pump 21 according to the detection value of the pressure transmitter 23.

[0064] In this embodiment, as Figure 1 As shown, pressure transmitter 23 is installed on the return water pipeline 10 to detect the pipeline pressure when circulating water returns from the external heat exchange equipment. The signal output terminal of pressure transmitter 23 is connected to the signal input terminal of the controller to transmit the pressure signal to the controller. Based on the return water pressure value detected by pressure transmitter 23, the controller determines the actual head requirement of the circulating water system and adjusts the operating frequency of the first circulating water pump 16 or the second circulating water pump 21 accordingly to match the output head of the circulating water pump with the system requirements.

[0065] The controller's pressure signal input is connected to the pressure transmitter 23, and its frequency control output is connected to the frequency converters of the first circulating water pump 16 and the second circulating water pump 21, respectively. When the pressure transmitter 23 detects that the return water pressure is higher than the set value, it indicates that the circulating water pump's output head is excessive. The controller outputs a control signal to the running circulating water pump frequency converter to reduce the circulating water pump speed. When the pressure transmitter 23 detects that the return water pressure is lower than the set value, the controller outputs a control signal to increase the frequency to increase the circulating water pump speed. Through pressure feedback regulation, the excessive head loss of the circulating water pump is reduced.

[0066] Specifically, such as Figure 1 As shown, the industrial circulating water energy-saving device also includes a bypass filter pipeline 24. One end of the bypass filter pipeline 24 is connected to the main outlet water pipeline 12, and the other end is connected to the water collection tank 3. A filter is installed on the bypass filter pipeline 24.

[0067] In this embodiment, as Figure 1 As shown, a portion of the circulating water is diverted from the main outlet water line 12 via a bypass filtration pipeline 24 for filtration. The inlet of the bypass filtration pipeline 24 is connected to the main outlet water line 12 via a T-joint, and the outlet of the bypass filtration pipeline 24 is directly discharged into the collection tank 3. The filter is installed on the bypass filtration pipeline 24. The pressure generated by the first circulating water pump 16 or the second circulating water pump 21 drives a portion of the circulating water to flow through the filter, filtering impurities from the flowing circulating water. The filtered clean water is then returned to the collection tank 3 to maintain the water quality of the circulating water.

[0068] Specifically, such as Figure 1 As shown, a flow meter 26 is installed on the main water outlet pipeline 12, and the flow meter 26 is connected to the controller.

[0069] In this embodiment, as Figure 1 As shown, the flow meter 26 is installed on the main outlet water pipe 12 to detect the flow rate of the circulating water supplied to the external heat exchange equipment. The signal output terminal of the flow meter 26 is connected to the signal input terminal of the controller to transmit the flow signal to the controller in real time. In addition, a return water temperature sensor is also installed on the return water pipe 10 of the circulating water pipe. The controller simultaneously receives the flow signal from the flow meter 26, the supply water temperature signal from the temperature sensor 5, and the return water temperature signal from the return water temperature sensor on the return water pipe 10.

[0070] The heat exchange in a circulating water system follows the heat balance equation Q = C × m × Δt, where Q is the heat load, i.e., the heat that the external heat exchange equipment needs to remove per unit time; C is the specific heat capacity of water, which is a constant; m is the mass flow rate of the circulating water; and Δt is the temperature difference between the supply and return water, i.e., the difference between the return water temperature and the supply water temperature. When the heat output of the external heat exchange equipment is fixed, the value of Q remains constant. Since C is a constant, the product of m × Δt is also a constant value. This indicates that the circulating water flow rate m is inversely proportional to the supply and return water temperature difference Δt. When the flow rate decreases, the temperature difference will inevitably increase; when the flow rate increases, the temperature difference will decrease accordingly.

[0071] Based on the above principles, the controller achieves energy-saving control by adjusting the circulating water flow rate. When the controller reduces the operating frequency of the first circulating water pump 16 or the second circulating water pump 21, the circulating water flow rate m decreases, the supply and return water temperature difference Δt increases accordingly, and the return water temperature rises. Although the return water temperature rises, because the total circulating water volume decreases, the amount of water that the cooling tower needs to process decreases. Therefore, the required ventilation volume is reduced while removing the same amount of heat. Thus, the controller can reduce the operating frequency of the cooling tower fan. Simultaneously, the power consumption of the circulating water pump is directly proportional to the flow rate; reducing the flow rate directly reduces the pump's energy consumption.

[0072] For example, when the external heat exchange equipment needs to remove 100kW of heat, the controller can select two operating modes: a high flow rate mode with a flow rate of 10m³ / h, where the supply and return water temperature difference is 2.4℃; and a low flow rate mode with a flow rate of 5m³ / h, where the supply and return water temperature difference increases to 4.8℃. The amount of heat removed is the same in both modes, but the low flow rate mode reduces the operating power of the circulating water pump and the cooling tower fan, thus achieving comprehensive energy savings for the circulating water system.

[0073] In some embodiments, flow meter 26 may be an electromagnetic flow meter.

[0074] Specifically, such as Figure 1 As shown, the industrial circulating water energy-saving device also includes a dosing device pipeline 25. The dosing device pipeline 25 is provided with an inlet and an outlet. The inlet is connected to the water supply pipeline, and the outlet is connected to the water collection tank 3. A dosing device is provided on the dosing device pipeline 25.

[0075] In this embodiment, as Figure 1 As shown, the inlet of the dosing device pipeline 25 is connected to the outlet main pipeline 12 of the water supply pipeline via a branch interface. A portion of the circulating water is drawn from the water supply pipeline as the carrier water for the chemical, and the outlet of the dosing device pipeline 25 is directly discharged into the collection tank 3. The dosing device is installed on the dosing device pipeline 25 to continuously inject the chemical into the circulating water. The chemical enters the collection tank 3 with the water flow and mixes with the circulating water in the collection tank 3.

[0076] The dosing device includes a chemical storage tank, a metering pump, and a mixer. The chemical storage tank stores water treatment chemicals. The inlet of the metering pump is connected to the chemical storage tank, and the outlet is connected to the mixer. The mixer is installed on the dosing device pipeline 25. The metering pump draws the chemicals from the storage tank and injects them quantitatively into the mixer. After the chemicals are fully mixed with the carrier water in the mixer, they are discharged into the collection tank 3.

[0077] The dosing device is existing technology and will not be described in detail in this embodiment.

[0078] Specifically, such as Figure 1 As shown, the industrial circulating water energy-saving device also includes a conductivity meter, which is installed in the water collection tank 3 and connected to the controller.

[0079] The controller is adapted to control the start and stop of the dosing device based on the conductivity value detected by the conductivity meter.

[0080] In this embodiment, as Figure 1 As shown, the conductivity meter is installed in the water collection tank 3. The probe of the conductivity meter is immersed in the circulating water to detect the conductivity value of the water. The signal output terminal of the conductivity meter is connected to the signal input terminal of the controller. The controller receives the conductivity signal transmitted by the conductivity meter. When the conductivity value exceeds the preset upper limit, the controller outputs a start signal to the metering pump of the dosing device, and the metering pump starts to work and adds chemicals to the circulating water. When the conductivity value drops to the preset lower limit, the controller outputs a stop signal, and the metering pump stops adding chemicals.

[0081] Example 2 is basically the same as Example 1, except that:

[0082] Specifically, such as Figure 2 As shown, the industrial circulating water energy-saving device also includes a bypass filter pipeline 24. The outlet end of the bypass filter pipeline 24 is connected to the main inlet pipeline 11, and the inlet end is connected to the main outlet pipeline 12. A filter is installed on the bypass filter pipeline 24.

[0083] In this embodiment, as Figure 2 As shown, a portion of the circulating water is diverted from the main outlet water line 12 for filtration. The inlet of the side filter line 24 is connected to the main outlet water line 12 via a T-joint, and the outlet of the side filter line 24 is connected to the main inlet water line 11. A filter is installed on the side filter line 24 to filter impurities from the circulating water. The filtered water then flows into the main inlet water line 11.

[0084] The bypass filtration line 24 utilizes the pressure in the main outlet line 12 to drive the circulating water through the filter. The filter requires an inlet pressure of 0.2-0.4 MPa, and the filtered water still retains residual pressure. The outlet end of the bypass filtration line 24 is connected to the main inlet line 11 near the inlet side of the first circulating water pump 16 and the second circulating water pump 21, using the residual pressure of the filtered water to increase the suction pressure of the circulating water pumps. A bypass filtration valve is also installed on the bypass filtration line 24 to control the bypass filtration flow rate.

[0085] The filter can be a sand filter, a bag filter, or a cartridge filter.

[0086] The specific embodiments described above further illustrate the technical problems, technical solutions, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An energy-saving device for industrial circulating water, characterized in that, include: Cooling tower (1), wherein the cooling tower (1) is provided with a water inlet; A cooling tower fan is provided above the cooling tower (1) and is adapted to ventilate and cool the circulating water in the cooling tower (1). A water collection tank (3) is provided at the bottom of the cooling tower (1). The water collection tank (3) is adapted to collect and store the circulating water of the cooling tower (1) after being cooled by the cooling tower fan. Multiple temperature sensors (5) are arranged at intervals along the height direction within the water collection tank (3); The circulating water pipeline includes a water supply pipeline and a return water pipeline (10). One end of the water supply pipeline is connected to the water collection tank (3), and the other end is connected to the cooling water inlet of the external heat exchange equipment. One end of the return water pipeline (10) is connected to the cooling water outlet of the external heat exchange equipment, and the other end is connected to the water inlet of the cooling tower (1). The controller is electrically connected to the temperature sensor (5) and the cooling tower fan respectively; The controller is adapted to adjust the operating frequency of the cooling tower fan based on the average temperature value of the plurality of temperature sensors (5).

2. The industrial circulating water energy-saving device according to claim 1, characterized in that: The temperature sensor (5) is configured as three, and the three temperature sensors (5) are respectively located at the upper, middle and lower parts of the water collection tank (3). The controller is adapted to adjust the operating frequency of the cooling tower fan according to the average value detected by the three temperature sensors (5).

3. The industrial circulating water energy-saving device according to claim 1, characterized in that: The controller also includes a delay component and a control component connected to each other. The delay component is adapted to control the control component. After the temperature value of the temperature sensor (5) changes, the delay component delays the control of the cooling tower fan according to a preset delay time in the delay component.

4. The industrial circulating water energy-saving device according to claim 1, characterized in that: The water supply pipeline includes: The main water inlet pipeline (11) is connected at one end to the water collection tank (3); The main outlet water pipeline (12) is connected at one end to the heat exchange equipment; The first branch pipe (13) is connected at one end to the other end of the main inlet pipe (11) and at the other end of the main outlet pipe (12). A first valve (14) and a first circulating water pump (16) are sequentially arranged on the first branch pipe (13) along the water flow direction. The second branch pipe (18) is connected at one end to the other end of the main inlet pipe (11) and at the other end to the other end of the main outlet pipe (12). A second valve (19) and a second circulating water pump (21) are sequentially installed on the second branch pipe (18) along the water flow direction.

5. The industrial circulating water energy-saving device according to claim 4, characterized in that: A pressure transmitter (23) is installed on the return water pipeline (10), and the pressure transmitter (23) is connected to the controller. The controller is adapted to adjust the first circulating water pump (16) or the second circulating water pump (21) according to the detection value of the pressure transmitter (23).

6. The industrial circulating water energy-saving device according to claim 4, characterized in that: It also includes a side filter pipeline (24), which has an outlet end and an inlet end. The outlet end is connected to the main inlet pipeline (11), and the inlet end is connected to the main outlet pipeline (12). The side filter pipeline (24) is equipped with a filter.

7. The industrial circulating water energy-saving device according to claim 4, characterized in that: A flow meter (26) is provided on the main water outlet pipeline (12), and the flow meter (26) is connected to the controller.

8. The industrial circulating water energy-saving device according to claim 1, characterized in that: It also includes a dosing device pipeline (25), which has an inlet and an outlet. The inlet is connected to the water supply pipeline, and the outlet is connected to the water collection tank (3). A dosing device is provided on the dosing device pipeline (25).

9. The industrial circulating water energy-saving device according to claim 8, characterized in that: It also includes a conductivity meter, which is installed in the water collection tank (3) and connected to the controller; The controller is adapted to control the start and stop of the dosing device based on the conductivity value detected by the conductivity meter.

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