Water ring vacuum pump unit and control method

Abstract

The invention provides a water ring vacuum pump unit and a control method, and belongs to the technical field of water ring vacuum pumps, the water ring vacuum pump unit comprises a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a vacuum pump, a steam-water separator, a cooling unit, a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor and a control unit, the first pipeline is connected with the vacuum pump, the vacuum pump is connected with the steam-water separator through a second pipeline, the steam-water separator is connected with the cooling unit through a third pipeline, the steam-water separator is connected with the vacuum pump through a fourth pipeline, and an exhaust pipe is arranged on the steam-water separator. Separated water circulates and flows back into the vacuum pump again, waste of water resources is reduced, meanwhile, water pollution is reduced, the separated water is cooled through the cooling unit and then flows back to the vacuum pump, the cavitation phenomenon is effectively avoided, and the service life of the vacuum pump is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of water ring vacuum pumps, and particularly to a water ring vacuum pump unit and a control method thereof. Background Art

[0002] A water ring vacuum pump is a positive displacement pump that forms a vacuum through liquid sealing. Its core component is an eccentric cylindrical pump chamber equipped with a radial vane impeller. During operation, an appropriate amount of working fluid (usually water) is injected. When the impeller rotates at high speed, the liquid forms an equi-thickness water ring under the action of centrifugal force, and together with the impeller, it forms a periodically changing sealed space to achieve gas inhalation, compression, and discharge. This pump has the characteristics of simple structure, stable operation, and strong corrosion resistance, and is widely used in gas suction, vacuum drying, and material transportation in fields such as chemical industry, pharmaceuticals, and food processing. Its unique water circulation system can not only maintain the vacuum degree but also achieve heat exchange, and is particularly suitable for working environments containing a small amount of condensable gases, with low maintenance costs and strong tolerance to polluted media.

[0003] However, traditional water ring vacuum pumps have cavitation problems during operation: when the local pressure of the liquid in the pump drops below its saturated vapor pressure, the liquid vaporizes to form bubbles. When these bubbles move to the high-pressure area, they quickly burst, generating shock waves, resulting in the erosion of the impeller surface material. Long-term cavitation will damage the impeller and affect the performance and lifespan of the pump. This phenomenon is particularly obvious in high-temperature environments. Summary of the Invention

[0004] The purpose of the present invention is to overcome the disadvantages and deficiencies of the prior art, and to provide a water ring vacuum pump unit and a control method thereof.

[0005] The technical solution adopted by the present invention is as follows: In the first aspect, the present application provides a water ring vacuum pump unit, including a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a vacuum pump, a steam-water separator, a cooling unit, a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, and a control unit. The first pipeline is connected to the vacuum pump for inputting gas thereto. The vacuum pump is connected to the steam-water separator through the second pipeline. The steam-water separator is connected to the cooling unit through the third pipeline. The steam-water separator is connected to the vacuum pump through the fourth pipeline. An exhaust pipe is provided on the steam-water separator. The steam-water separator is used to separate the water vapor transported by the vacuum pump, and the separated gas is discharged through the exhaust pipe, and the separated water is cooled by the cooling unit and then transported back to the vacuum pump. The first temperature sensor is used to detect the ambient temperature, the second temperature sensor is used to detect the temperature of the return water, the third temperature sensor is used to detect the temperature of the cooling water, and the fourth temperature sensor is used to detect the working temperature of the vacuum pump.

[0006] In some embodiments, a fifth pipeline is provided on the first pipeline, a vacuum gauge is provided on the fifth pipeline, and a second control valve, a third control valve are respectively provided on both sides of the vacuum gauge and connected to the first pipeline.

[0007] In some embodiments, a check valve is provided at one end of the first pipeline close to the vacuum pump, and an air ejector is provided on a portion of the first pipeline between the second control valve and the third control valve.

[0008] In some embodiments, a liquid level gauge is provided on the steam-water separator, a water inlet pipe and a drain pipe are provided on the steam-water separator, a water inlet control valve is provided on the water inlet pipe, and a drain control valve is provided on the drain pipe.

[0009] In some embodiments, a first control valve is provided at the inlet end of the first pipeline for controlling the gas flow rate, and a fourth control valve is provided on the fourth pipeline for controlling the cooling water flow rate.

[0010] In some embodiments, a sixth pipeline is provided on the exhaust pipe and connected to the first pipeline through the sixth pipeline, and a fifth control valve is provided at one end of the sixth pipeline close to the exhaust pipe.

[0011] In some embodiments, a seventh pipeline is provided between the steam-water separator and the inlet end of the vacuum pump, and a sixth control valve is provided on the seventh pipeline.

[0012] In a second aspect, the present application provides a control method applied to the water ring vacuum pump unit, including the following steps: S1: Obtain the ambient temperature based on the first temperature sensor, compare it with the pre-stored optimal working temperature of the vacuum pump, and generate an estimated temperature of the cooling water according to the difference between the two; S2: Obtain the actual working temperature of the vacuum pump in real time based on the fourth temperature sensor, calculate the deviation value between it and the optimal working temperature, and based on the current deviation value, perform progressive correction on the estimated temperature according to a preset convergence coefficient until the absolute value of the deviation value does not exceed the allowable range; S3: Record an operation data set formed by the optimal working temperature, ambient temperature, estimated temperature, actual working temperature and deviation value in each adjustment process in the database. When the deviation amount of the new data set is less than the historical record under the same working conditions, perform data optimization and replacement; where the same working conditions refer to the same optimal working temperature and ambient temperature; S4: When the water ring vacuum pump unit operates subsequently, directly call the corresponding estimated temperature in the database based on the ambient temperature.

[0013] In some embodiments, in step S2, based on the temperature of the returned water obtained by the second temperature sensor, adjust the cooling power of the cooling unit so that the temperature of the cooling water approaches the estimated temperature. Based on the actual temperature of the cooling water obtained by the third temperature sensor, compare it with the estimated temperature. If it exceeds the allowable range, readjust the cooling power of the cooling unit.

[0014] In some embodiments, if the current ambient temperature is lower than the optimal operating temperature, open the fifth control valve and the sixth control valve, and then adjust the opening degree of the fourth control valve according to the actual operating temperature obtained by the fourth temperature sensor to control the actual operating temperature to approach the optimal operating temperature; When the actual operating temperature is lower than the optimal operating temperature, close the fourth control valve, and reduce the power of the cooling unit or turn off the cooling unit.

[0015] The beneficial effects of the present invention are as follows: In the present invention, the steam and water are separated by a steam-water separator, and the separated water is recycled back into the vacuum pump, saving the waste of water resources, reducing water pollution at the same time, and cooling the separated water by a cooling unit and then recycling it back into the vacuum pump, effectively avoiding the occurrence of cavitation phenomenon and prolonging the service life of the vacuum pump.

[0016] In the present invention, through the coordinated control of a four-way temperature sensing system (ambient temperature, return water temperature, cooling water temperature, pump body temperature) and a closed-loop water circulation system, the dynamic optimization of cavitation protection is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, obtaining other drawings based on these drawings still belongs to the scope of the present invention.

[0018] Figure 1 Schematic diagram of a water ring vacuum pump unit in the present invention Figure 1 ; Figure 2 Schematic diagram of a water ring vacuum pump unit in the present invention Figure 2 ; Figure 3 Schematic diagram of a water ring vacuum pump unit in the present invention Figure 3 ; Figure 4 Schematic diagram of another water ring vacuum pump unit in the present invention; Figure 5 Flowchart of the control method in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following description provides specific application scenarios and requirements of this specification, aiming to enable those skilled in the art to manufacture and use the content in this specification. For those skilled in the art, various partial modifications to the disclosed embodiments are obvious, and the general principles defined here can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the disclosed embodiments, but has the broadest scope consistent with the claims.

[0020] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the orientation or positional relationships indicated by terms such as "longitudinal", "lateral", "radial", "length", "width", "thickness", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation.

[0021] Secondly, terms such as "first", "second" and similar words do not represent any order, quantity or importance, but are only used to distinguish different components, and should not be construed as a limitation on the embodiments of this application.

[0022] In addition, terms such as "installed", "set", "provided with", "connected", "linked" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, elements or components.

[0023] For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0024] The flowcharts used in this application illustrate the operations implemented by the system according to some embodiments in this specification. It should be clearly understood that the operations in the flowchart may not be implemented in sequence. On the contrary, the operations can be implemented in reverse order or simultaneously. In addition, one or more other operations can be added to the flowchart. One or more operations can be removed from the flowchart.

[0025] Regarding the drawings of this application, it should be clearly understood that the drawings are only for the purpose of illustration and description, and are not intended to limit the scope of this specification. It should also be understood that the drawings are not necessarily drawn to scale.

[0026] As Figures 1 to 3As shown in the figure, this specification provides a water ring vacuum pump unit, including a first pipeline 1, a second pipeline 2, a third pipeline 3, a fourth pipeline 4, a vacuum pump 5, a steam-water separator 6, and a cooling unit 7. The first pipeline 1 is connected to the vacuum pump 5 for inputting gas thereto. The vacuum pump 5 is connected to the steam-water separator 6 through the second pipeline 2. The steam-water separator 6 is connected to the cooling unit 7 through the third pipeline 3. The steam-water separator 6 is connected to the vacuum pump 5 through the fourth pipeline 4. An exhaust pipe 8 is provided on the steam-water separator 6. The steam-water separator 6 is used to separate the water vapor transported by the vacuum pump 5. The separated gas is discharged through the exhaust pipe 8, and the separated water is cooled by the cooling unit 7 and then transported back to the vacuum pump 5. With such a setting, the steam and water are separated by the steam-water separator 6, and the separated water is recycled back into the vacuum pump 5, saving the waste of water resources, reducing water pollution at the same time, and cooling the separated water by the cooling unit and then returning it to the vacuum pump, effectively avoiding the occurrence of cavitation phenomenon and prolonging the service life of the vacuum pump.

[0027] A first control valve 9 is provided at the inlet end of the first pipeline 1. The first control valve 9 is used to control the gas flow rate, allowing the system to optimize the gas input under different working conditions, ensuring that the vacuum pump 5 operates in the best state, thereby improving the efficiency of the entire system.

[0028] In some embodiments, a fifth pipeline 10 is provided on the first pipeline 1, and a vacuum gauge 11 is provided on the fifth pipeline 10. By monitoring the vacuum degree, the operator can timely understand the performance of the pump, detect faults or abnormalities early, and improve the reliability of the system. Second control valve 12 and third control valve 13 are respectively provided on both sides of the vacuum gauge 11 and connected to the first pipeline 1, enabling the operator to flexibly adjust the gas flow rate when monitoring changes in the vacuum degree, helping to quickly respond to system changes, preventing the occurrence of an excessive vacuum state, and thus avoiding damage to components such as the vacuum pump and pipeline due to excessive air extraction.

[0029] In some embodiments, a check valve 14 is provided at one end of the first pipeline 1 close to the vacuum pump 5 to prevent gas from flowing back into the vacuum pump when the system stops or fails.

[0030] In some embodiments, an air ejector 15 is provided on the part of the first pipeline 1 between the second control valve 12 and the third control valve 13, which uses atmospheric pressure to introduce external air into the system. This can provide additional air flow when the vacuum pump is working, thereby improving the gas fluidity and the suction capacity of the pump.

[0031] In some embodiments, a liquid level gauge 16 is provided on the steam-water separator 6. An inlet pipe 17 and a drain pipe 18 are provided on the steam-water separator 6. An inlet control valve is provided on the inlet pipe 17, and a drain control valve is provided on the drain pipe 18. The liquid level gauge 16 can monitor the liquid level in the steam-water separator in real time, ensuring that the water volume during the operation of the water ring pump always meets the requirements, which helps to improve the working efficiency and stability of the pump.

[0032] A first temperature sensor is provided on the first pipeline 1 for detecting the ambient temperature. A second temperature sensor is provided on the third pipeline 3 for detecting the temperature of the water input into the cooling unit 7, that is, the temperature of the return water. A third temperature sensor and a fourth control valve 19 are provided on the fourth pipeline 4. The third temperature sensor is used for detecting the temperature of the cooling water; the fourth control valve 19 is used for controlling the flow rate of the cooling water. A fourth temperature sensor is provided on the vacuum pump 5 for detecting the working temperature of the vacuum pump 5. With such a setting, by real-time monitoring of the temperatures at each key part, potential problems can be discovered in a timely manner, and corresponding measures can be taken to prevent equipment damage or failures and improve the safety of the system.

[0033] In some embodiments, as Figure 4 shown, a sixth pipeline 20 is provided on the exhaust pipe 8 and is connected to the first pipeline 1 through the sixth pipeline 20, generally connected between the first control valve 9 and the ejector 15. A fifth control valve 21 is provided at one end of the sixth pipeline 20 close to the exhaust pipe 8 to prevent the gas discharged from the steam-water separator 6 from affecting the gas normally inhaled by the first pipeline 1 when the fifth control valve 21 is not opened. A seventh pipeline 22 is provided between the steam-water separator 6 and the inlet end of the vacuum pump 5. A sixth control valve 23 is provided on the seventh pipeline 22. The sixth control valve 23 is provided at one end of the seventh pipeline 22 close to the steam-water separator 6.

[0034] It should be understood that in this water ring vacuum pump unit, each control valve is set as an on-off valve, a flow regulating valve, etc. according to the required functions. The valves in the drawings are only for illustration, and each temperature sensor can adopt common temperature detectors in the fields of pipelines, pump bodies, valves, etc.

[0035] As Figure 5 shown, based on the above-mentioned water ring vacuum pump unit in this specification, a control method is provided, including the following steps: S1: Obtain the ambient temperature based on the first temperature sensor, compare it with the pre-stored optimal working temperature of the vacuum pump 5, and generate an estimated temperature of the cooling water according to the difference between the two; if the ambient temperature is higher than the optimal working temperature, then the temperature of the gas entering the vacuum pump will be relatively high, so it is necessary to lower the temperature of the cooling water, generally to below the optimal working temperature.

[0036] If the current ambient temperature is lower than the optimal operating temperature, open the fifth control valve 21 and the sixth control valve 23, and then adjust the opening degree of the fourth control valve 19 according to the actual operating temperature obtained by the fourth temperature sensor to control the actual operating temperature to approach the optimal operating temperature.

[0037] When the actual operating temperature is lower than the optimal operating temperature, close the fourth control valve 19 and reduce the power of the cooling unit 7 or turn off the cooling unit 7.

[0038] S2: Based on the actual operating temperature of the vacuum pump 5 obtained by the fourth temperature sensor in real time, calculate the deviation value between it and the optimal operating temperature, and based on the current deviation value, perform progressive correction on the estimated temperature according to the preset convergence coefficient until the absolute value of the deviation does not exceed the allowable range; use the preset convergence coefficient to avoid overshoot or oscillation. The allowable range is the deviation range, which is set according to the actual working conditions, such as ±1°C, which is a common industrial standard. For example, the initial estimated temperature is 38°C, but the actual operating temperature is 48°C, and the deviation is +8°C. According to the preset convergence coefficient, such as the convergence coefficient is 0.5, the correction amount each time is the deviation multiplied by the coefficient, that is, 4°C. In this way, the corrected cooling water temperature is reduced to 34°C, and the actual temperature is detected again until the deviation enters the allowable range.

[0039] Further, when adopt aggressive correction , quickly eliminate large deviations. Among them, is the deviation between the actual operating temperature and the optimal operating temperature.

[0040] In the interval, start proportional-integral regulation to avoid overshoot, and the overshoot .

[0041] When it reaches , switch to the maintenance mode, and only perform micro-amplitude fluctuation compensation.

[0042] Using this method, feedback control is realized only through the temperature sensor, without the need for a large amount of calculation and with strong real-time performance. Specifically, if the optimal temperature of the cooling water is directly calculated based on the optimal operating temperature of the vacuum pump and the ambient temperature, a heat balance model needs to be involved. The heat generated by the vacuum pump during operation needs to be taken away by the cooling water, and at the same time, the ambient air inhaled will also bring in heat or take away heat, which depends on the difference between the ambient temperature and the internal temperature of the pump. Therefore, in the heat balance equation, these two parts of heat exchange need to be considered, and the intake air flow and the coolant flow need to be considered, etc.

[0043] When the ambient temperature is higher than the optimal operating temperature, the ambient air will bring additional heat. At this time, the cooling water temperature needs to be lower than the optimal operating temperature to provide stronger cooling capacity and offset the heat brought by the ambient air. Conversely, when the ambient temperature is lower than the optimal operating temperature, the ambient air may help with cooling. At this time, the cooling water temperature can be appropriately increased to reduce cooling energy consumption. Therefore, the determination of the optimal cooling water temperature should be a dynamic adjustment process, calculated in real time according to the changes in ambient temperature. This may require the establishment of a mathematical model to quantify the relationship between ambient temperature and cooling water temperature. This requires a large amount of data collection and data calculation.

[0044] In step S2, based on the return water temperature acquired by the second temperature sensor, the cooling power of the cooling unit 7 is adjusted so that the cooling water temperature approaches the estimated temperature, thereby ensuring that the cooling unit 7 is adjusted quickly.

[0045] The actual temperature of the cooling water obtained by the third temperature sensor is compared with the estimated temperature. If it exceeds the tolerance range, the cooling power of the cooling unit 7 is readjusted, and an additional calibration is performed to improve the reliability of the system.

[0046] S3: Recording the optimal working temperature, ambient temperature, estimated temperature, actual working temperature and deviation value in each adjustment process in the database to form an operation data set, and when the deviation of the new data set is less than the historical record of the same working condition, perform data optimization replacement; wherein the same working condition means the same optimal working temperature and ambient temperature; S4: When the water ring vacuum pump unit is subsequently operated, the corresponding estimated temperature in the database is directly called based on the ambient temperature. If there is no identical ambient temperature, the estimated temperature corresponding to the similar ambient temperature is used, and steps S2 and S3 are repeated.

[0047] By adopting the above method, the continuous evolution of the control system is achieved by establishing a working condition-temperature self-optimization database, and the estimated temperature under the same working condition is dynamically calibrated and optimized at the data level, which not only ensures the reliable prediction capability of the new working condition in the initial stage, but also automatically selects better operating parameters through the deviation comparison mechanism to enable the system to continuously converge and improve the temperature prediction accuracy under repeated working conditions. After optimization, the temperature control deviation under the same working condition can be reduced, while avoiding the real-time computing load required by the traditional model predictive control, taking into account both control accuracy and response speed.

[0048] In summary, after reading this detailed disclosure, those skilled in the art will appreciate that the foregoing detailed disclosure may be presented only by way of example and may not be restrictive. Although not explicitly stated herein, those skilled in the art will appreciate that the requirements of this application encompass various reasonable changes, improvements and modifications to the embodiments. These changes, improvements and modifications are intended to be proposed by the present application and are within the spirit and scope of the exemplary embodiments of the present application.

[0049] In addition, it should be understood that in the foregoing description of the embodiments of the present application, for the purpose of helping to understand a feature and for the purpose of simplifying the present application, the present application combines various features in a single embodiment, drawing, or description thereof. However, this does not mean that the combination of these features is necessary, and those skilled in the art may very well mark out some of the devices as separate embodiments when reading the present application. That is to say, the embodiments in the present application can also be understood as the integration of multiple sub-embodiments. And it also holds when the content of each sub-embodiment is less than all the features of a single foregoing disclosed embodiment.

[0050] Finally, it should be understood that the embodiments of the application disclosed herein are illustrative of the principles of the embodiments of the present application. Other modified embodiments are also within the scope of the present application. Therefore, the embodiments disclosed in the present application are merely examples and not limitations. Those skilled in the art can adopt alternative configurations according to the embodiments in the present application to implement the application in the present application. Therefore, the embodiments of the present application are not limited to the embodiments precisely described in the application.

Claims

1. A water-ring vacuum pump unit, characterized in that, It includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a vacuum pump, a steam-water separator, a cooling unit, a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor and a control unit. The first pipeline is connected to the vacuum pump for inputting gas thereto. The vacuum pump is connected to the steam-water separator through the second pipeline. The steam-water separator is connected to the cooling unit through the third pipeline. The steam-water separator is connected to the vacuum pump through the fourth pipeline. An exhaust pipe is provided on the steam-water separator. The steam-water separator is used for separating the water vapor conveyed by the vacuum pump. The separated gas is discharged through the exhaust pipe, and the separated water is cooled by the cooling unit and then conveyed back to the vacuum pump. The first temperature sensor is used for detecting the ambient temperature. The second temperature sensor is used for detecting the temperature of the return water. The third temperature sensor is used for detecting the temperature of the cooling water. The fourth temperature sensor is used for detecting the operating temperature of the vacuum pump.

2. The water ring vacuum pump unit according to claim 1, characterized in that, A fifth pipeline is provided on the first pipeline. A vacuum gauge is provided on the fifth pipeline, and a second control valve, a third control valve are respectively provided on both sides of the vacuum gauge and connected to the first pipeline.

3. The water ring vacuum pump unit according to claim 1, characterized in that, A check valve is provided at one end of the first pipeline close to the vacuum pump, and an air ejector is provided on the part of the first pipeline between the second control valve and the third control valve.

4. A water ring vacuum pump unit according to claim 1, characterized in that, A liquid level gauge is provided on the steam-water separator. An inlet pipe and a drain pipe are provided on the steam-water separator. An inlet control valve is provided on the inlet pipe, and a drain control valve is provided on the drain pipe.

5. The water ring vacuum pump unit according to claim 1, wherein, A first control valve is provided at the inlet end of the first pipeline for controlling the gas flow rate. A fourth control valve is provided on the fourth pipeline for controlling the cooling water flow rate.

6. The water ring vacuum pump unit according to claim 1, characterized in that, A sixth pipeline is provided on the exhaust pipe and connected to the first pipeline through the sixth pipeline. A fifth control valve is provided at one end of the sixth pipeline close to the exhaust pipe.

7. A water ring vacuum pump unit according to claim 6, characterized in that, A seventh pipeline is provided between the steam-water separator and the inlet end of the vacuum pump, and a sixth control valve is provided on the seventh pipeline.

8. A control method applied to the water ring vacuum pump unit according to any one of claims 1 to 7, characterized in that, It includes the following steps: S1: Obtain the ambient temperature based on the first temperature sensor, compare it with the pre-stored optimal operating temperature of the vacuum pump, and generate an estimated temperature of the cooling water according to the difference between the two. S2: Obtain the actual operating temperature of the vacuum pump in real time based on the fourth temperature sensor, calculate the deviation value between it and the optimal operating temperature, and based on the current deviation value, perform progressive correction on the estimated temperature according to a preset convergence coefficient until the absolute value of the deviation value does not exceed the allowable range. S3: Record an operation data set formed by the optimal operating temperature, ambient temperature, estimated temperature, actual operating temperature and deviation value in each adjustment process in the database. When the deviation amount of the new data group is less than the historical record under the same working conditions, perform data optimization and replacement; where the same working conditions refer to the same optimal operating temperature and ambient temperature. S4: When the water ring vacuum pump unit operates subsequently, directly call the corresponding estimated temperature in the database based on the ambient temperature.

9. The control method according to claim 8, characterized in that In step S2, based on the temperature of the return water obtained by the second temperature sensor, adjust the cooling power of the cooling unit so that the temperature of the cooling water approaches the estimated temperature. Based on the actual temperature of the cooling water obtained by the third temperature sensor, compare it with the estimated temperature. If it exceeds the allowable range, readjust the cooling power of the cooling unit.

10. The control method according to claim 8, characterized in that If the current ambient temperature is lower than the optimal operating temperature, open the fifth control valve and the sixth control valve, and then adjust the opening degree of the fourth control valve according to the actual operating temperature obtained by the fourth temperature sensor to control the actual operating temperature to approach the optimal operating temperature; When the actual operating temperature is lower than the optimal operating temperature, close the fourth control valve and reduce the power of the cooling unit or turn off the cooling unit.

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