A cooling system control method for a multi-stage centrifugal compressor and a cooling system

Abstract

The application belongs to the technical field of air compressors, and provides a cooling system control method and a cooling system of a multistage centrifugal compressor. The method is characterized in that pressure sensors and liquid level sensors are respectively installed at key positions such as each stage intercooler, aftercooler, water inlet and water outlet separators, and power source heat exchanger. Through the collection of water pressure and liquid level data of each monitoring point, combined with the cooling water temperature difference, the control system executes safety exhaust judgment logic and energy-saving adjustment logic. When the water pressure and liquid level meet the preset conditions, the exhaust operation is allowed to be executed. When the water pressure and liquid level do not meet the preset conditions, manual operation is prohibited and automatic safety pressure relief discharge is executed. After the pressure is reduced below the safety threshold, the exhaust is completed, thereby effectively avoiding the risk of manual operation under pressure. Through the temperature sensors, the temperature difference of each monitoring point is detected. When the cooling water temperature difference is lower than the set value and the liquid level is higher than the set value, the cooling water supply amount is automatically reduced to realize energy saving.

Description

Technical Field

[0001] This invention relates to the field of air compressor technology, and in particular to a cooling system control method and cooling system for a multi-stage centrifugal compressor. Background Technology

[0002] Centrifugal compressors typically employ multi-stage compression and interstage cooling. The high-temperature air exiting each stage of compression must be cooled by an intercooler before entering the next stage for further compression. When the compressor power is high, a liquid-cooled (water-cooled) system is preferred. This system generally consists of external equipment such as an externally circulating cooling tower, water pump, and piping. In existing liquid-cooled systems, cooling water enters through the main inlet pipe and is distributed to various intercoolers, aftercoolers, and plate heat exchangers, completing heat exchange before being discharged through the main outlet pipe.

[0003] However, existing centrifugal compressor liquid cooling systems still have the following shortcomings: There are potential safety hazards. Existing water coolers and cooling medium channels (pipelines) generally lack pressure relief and air venting devices. Taking intercoolers as an example, while relevant technical regulations require the installation of liquid level controllers and indicators, they do not provide a safe venting control scheme based on both pressure and liquid level assessments. When operators perform maintenance and venting of the cooling system, they cannot ascertain the true internal pressure and air accumulation, often recklessly removing plugs or opening vents while the system is pressurized. This pressurized operation can easily lead to the splashing of high-temperature cooling medium, causing burns or impact injuries to operators, and can also allow cooling medium to enter the equipment, causing electrical short circuits and moisture damage, posing a serious safety hazard.

[0004] The lack of effective system status awareness means that operators in existing cooling systems cannot obtain real-time information on key parameters such as the space occupied by air and the liquid level inside each stage of the cooler and piping. When air enters the system, it not only reduces the heat exchange efficiency of the coolers but may also lead to uneven distribution of cooling water flow, affecting the overall operating efficiency of the compressor. The lack of effective status awareness methods makes it difficult to accurately determine the timing of exhaust operations, often requiring blind operation based on experience.

[0005] The technical problem to be solved by this invention is: how to solve the problem that the existing compressor cooling system cannot accurately obtain parameters such as water pressure and liquid level in real time, which easily leads to safety accidents due to pressurized operation during maintenance. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a cooling system control method and cooling system for a multi-stage centrifugal compressor. By monitoring the water pressure and liquid level at key locations of the cooling system and judging whether the conditions for exhaust are met based on the data, the operation and maintenance of the air compressor are made safer and more efficient.

[0007] The first aspect of this application is to provide a cooling system control method for a multi-stage centrifugal compressor, comprising: Multiple monitoring points are set in the cooling system, including: water inlet water separator, at least one stage intercooler, aftercooler, power source heat exchanger and water outlet water separator. Each monitoring point is equipped with a pressure sensor and a liquid level sensor. Real-time acquisition of water pressure and liquid level data at each monitoring point; Determine whether the cooling system meets the exhaust safety conditions based on water pressure and liquid level data; The exhaust safety conditions are: the water pressure data is less than or equal to the preset pressure value X and the liquid level data is greater than or equal to the preset liquid level value Y, or the water pressure data is less than or equal to the preset pressure value X and the liquid level data is less than or equal to the preset liquid level value Y. When the venting safety conditions are met, the venting operation is permitted; when the venting safety conditions are not met, the manual venting operation is prohibited, and the automatic venting actuator is controlled by the control system to safely release pressure and discharge water. The venting operation is completed after the water pressure data drops below the preset pressure value X.

[0008] The cooling system control method of the multi-stage centrifugal compressor of this application sets monitoring points at various locations in the cooling system where air is easily trapped, and sets pressure sensors and liquid level sensors at each monitoring point. By utilizing the dual judgment logic of pressure sensors and liquid level sensors, it ensures that the exhaust operation is carried out only under safe conditions, completely eliminating the risk of personnel injury and equipment damage caused by pressurized operation. The exhaust operation has almost zero safety risk, and can scientifically and intuitively judge the air accumulation status inside the cooling system, reducing blind manual operation and avoiding equipment damage and personnel injury caused by cooling water splashing.

[0009] In some implementations, it also includes: Temperature sensors installed at the inlet and outlet of each monitoring point are used to obtain real-time temperature difference data at each monitoring point. When the water pressure of the cooling system remains constant, the cooling water supply of the cooling system is adjusted according to the cooling water temperature difference data and liquid level data.

[0010] By adopting the above technical solution, the cooling water supply can be dynamically adjusted based on a comprehensive judgment of the cooling water temperature difference and liquid level data under constant water pressure, thus avoiding the waste of water resources and energy caused by excessive cooling and achieving greater energy efficiency.

[0011] In some implementations, when the cooling water temperature difference is less than a preset temperature difference value Z and the liquid level data is greater than or equal to a preset liquid level value Y, the cooling water supply is reduced and the air inside the system is discharged. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, a fault warning is issued and the air inside the system is discharged. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the current operating state is maintained. A fault warning is issued when the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y.

[0012] Using the above technical solution, when the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level is greater than the preset liquid level value Y, it indicates that the cooling water supply is too large and the heat exchange efficiency has a margin. At this time, the control system will promptly provide feedback to the customer through the Internet of Things system, which can appropriately reduce the cooling water supply. At the same time, it can automatically or manually discharge the air inside the system to reduce the cooling water volume and achieve energy saving effect. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level is greater than the preset liquid level value Y, it indicates that the heat exchange is insufficient and there is too much air in the system. At this time, the control system will issue a fault warning and control the exhaust actuator to safely release pressure and discharge air to remove the air inside the system. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level is less than the preset liquid level value Y, it indicates that the cooling system is operating normally and can maintain normal operation without adjustment. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level is less than the preset liquid level value Y, it indicates that the heat exchange is seriously insufficient. At this time, the control system will issue a fault warning to facilitate maintenance and troubleshooting.

[0013] In some implementations, the operation of reducing the cooling water supply specifically involves: determining the reduction range of the cooling water supply based on the difference between the cooling water temperature difference and the preset temperature difference value Z, and controlling the operation of the water pumps in the cooling system based on the water supply.

[0014] By adopting the above technical solution, the water supply volume can be adjusted by controlling the speed or operating frequency of the water pump, so that the water supply volume is matched with the cooling demand, thus saving more energy and water resources.

[0015] In some implementations, the pressure sensor and the level sensor are positioned at a high position at each monitoring point.

[0016] By adopting the above technical solution, it is possible to accurately detect the true situation of air accumulation and liquid level at each monitoring point.

[0017] In some implementations, the power source heat exchanger is used to regulate the temperature of the motor and / or frequency converter.

[0018] Using the above technical solution, the motor and / or frequency converter need to be cooled with coolant (oil). A pump draws cold coolant from the storage tank and then sends it to the inlet of each stage of the motor and the inlet of each stage of the frequency converter. The cold coolant carries away the heat from the motor and frequency converter and becomes hot coolant. The hot coolant enters the power source heat exchanger. After exchanging heat with the cooling water, the cold coolant returns to the storage tank. This cycle is repeated to control the temperature of the motor and / or frequency converter and ensure that the motor and / or frequency converter always operate at a suitable temperature.

[0019] In some implementations, the venting operation includes manually removing the plug at the monitoring point to vent air and / or activating an automatic venting device to vent air.

[0020] Using the above technical solution, exhaust can be performed manually or automatically via an automatic exhaust device, depending on actual needs.

[0021] In some implementations, fault warnings are sent to remote terminals in real time via an Internet of Things (IoT) system.

[0022] Using the above technical solution, users can monitor the operating status of the cooling system through a remote terminal, and remotely control the exhaust and adjust the delivery of cooling water through the remote terminal.

[0023] A second aspect of this application is to provide a cooling system for a multi-stage centrifugal compressor for performing any of the methods described above, comprising: Multiple monitoring units are set at multiple monitoring points in the cooling system. Each monitoring unit includes a pressure sensor and a liquid level sensor to acquire water pressure data and liquid level data of the corresponding monitoring point in real time. The control system is connected to each monitoring unit to receive water pressure and liquid level data from each monitoring point, and to determine whether the cooling system meets the exhaust safety conditions based on the water pressure and liquid level data. The exhaust actuator is used to allow the exhaust operation when the control system determines that the exhaust safety conditions are met, and to prohibit the manual exhaust operation when the exhaust safety conditions are not met. The control system controls the exhaust actuator to safely release pressure and discharge water. The exhaust operation is completed after the water pressure data drops below the preset pressure value X.

[0024] The cooling system of the multi-stage centrifugal compressor in this application uses a dual judgment logic of pressure sensor and liquid level sensor to ensure that the exhaust operation is carried out only under safe conditions, completely eliminating the risk of personnel injury and equipment damage caused by pressurized operation. The exhaust operation has a low risk, and the air accumulation status inside the cooling system can be judged scientifically and intuitively, reducing blind manual operation and avoiding equipment moisture caused by cooling water splashing.

[0025] In some implementations, the monitoring unit further includes a temperature sensor for acquiring cooling water temperature difference data at the inlet and outlet of each monitoring point in the cooling system; the control system is also used to adjust the cooling water supply of the cooling system based on the cooling water temperature difference data and liquid level data when the water pressure of the cooling system remains constant. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues a command to reduce the cooling water supply and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues a fault warning and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system maintains the current operating state. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system issues a fault warning.

[0026] By adopting the above technical solution, the cooling water supply can be dynamically adjusted based on the comprehensive judgment of cooling water temperature difference and liquid level data under constant water pressure, avoiding the waste of water resources and energy caused by excessive cooling, thus saving more energy. Furthermore, it can provide fault early warning based on monitoring data, thereby improving the efficiency of fault troubleshooting. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the cooling system of a multi-stage centrifugal compressor according to a preferred embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the cooling system control method for a multi-stage centrifugal compressor from another perspective; Figure 3 for Figure 1 A schematic diagram of the cooling system control method for a multi-stage centrifugal compressor from another perspective; Figure 4 for Figure 1 The diagram shows a simplified structure of the cooling system for a multi-stage centrifugal compressor.

[0028] In the diagram: 10, water inlet water separator; 20, intercooler; 30, aftercooler; 40, power source heat exchanger; 50, water outlet water separator; 60, pressure sensor; 70, liquid level sensor; 80, temperature sensor; 90, motor; 100, main unit. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. When the number of elements is referred to as "multiple," it can be any number of two or more. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] Please see Figures 1 to 4 A preferred embodiment of the present invention provides a cooling system control method for a multi-stage centrifugal compressor, comprising: Multiple monitoring points are set in the cooling system, including: water inlet water separator 10, at least one intermediate cooler 20, aftercooler 30, power source heat exchanger 40, and water outlet water separator 50. Each monitoring point is equipped with a pressure sensor 60 and a liquid level sensor 70. Real-time acquisition of water pressure and liquid level data at each monitoring point; Determine whether the cooling system meets the exhaust safety conditions based on water pressure and liquid level data; The exhaust safety conditions are: the water pressure data is less than or equal to the preset pressure value X and the liquid level data is greater than or equal to the preset liquid level value Y, or the water pressure data is less than or equal to the preset pressure value X and the liquid level data is less than or equal to the preset liquid level value Y. When the venting safety conditions are met, the venting operation is permitted; when the venting safety conditions are not met, the manual venting operation is prohibited, and the automatic venting actuator is controlled by the control system to safely release pressure and discharge water. The venting operation is completed after the water pressure data drops below the preset pressure value X.

[0033] The cooling system control method of the multi-stage centrifugal compressor of this application sets monitoring points at various locations in the cooling system where air is easily trapped, and sets pressure sensors 60 and liquid level sensors 70 at each monitoring point. By utilizing the dual judgment logic of pressure sensors 60 and liquid level sensors 70, it ensures that the exhaust operation is carried out only under safe conditions, completely eliminating the risk of personnel injury and equipment damage caused by pressurized operation. The exhaust operation has almost zero safety risk, and can scientifically and intuitively judge the air accumulation status inside the cooling system, reduce blind manual operation, and avoid equipment moisture caused by cooling water splashing.

[0034] Specifically, the safety exhaust judgment logic in this embodiment is as follows: When the water pressure is less than or equal to the preset pressure value X and the liquid level is greater than or equal to the preset liquid level value Y, it is permissible to remove the plug or start the automatic air venting device to release air. When the water pressure is greater than the preset pressure value X and the liquid level is greater than or equal to the preset liquid level value Y, it is forbidden to directly remove the plug or rashly start the venting device. At this time, the control system will automatically start the safety pressure relief device to slowly release the internal high-pressure gas at a controllable rate. After the water pressure drops below the preset pressure value X, the venting operation will be completed. When the water pressure is less than or equal to the preset pressure value X and the liquid level is less than the preset liquid level value Y, it is permissible to remove the plug or start the automatic air venting device to release air. When the water pressure is greater than the preset pressure value X and the liquid level is less than the preset liquid level value Y, it is forbidden to directly remove the plug or rashly start the venting device. At this time, the control system will automatically start the safety pressure relief device to slowly release the internal high-pressure gas at a controllable rate. After the water pressure drops below the preset pressure value X, the venting operation will be completed.

[0035] The core of the above logic is that when the water pressure is greater than the preset pressure value X, there may be high-pressure air (trapped air) in the system. If the plug is removed directly to release the air at this time, a high-temperature and high-pressure medium splashing accident is very likely to occur. Therefore, this invention prohibits direct manual operation in this situation. Instead, the control system automatically starts the pressure relief device to perform controllable, phased, and safe pressure relief. The venting action is only allowed to be completed after the internal pressure of the system drops back to below the safe threshold (i.e., the preset pressure value X). When the water pressure is less than or equal to the preset pressure value X, it indicates that the system pressure is at a safe level, and the venting operation is safe and feasible. This is because circulating water carries air into the cooling system. When there is space inside the cooling system, the air brought in by the water pump gradually accumulates, forming a compressible air cavity, and its pressure can rise to close to the water pump head (usually 3-5 kg). The preset pressure value X is the safe threshold for determining whether there is dangerous pressure inside the system, and the preset liquid level value Y is the safe threshold for determining whether the internal water level is sufficient.

[0036] In the above logic, the preset pressure value X is the safe water pressure threshold, and the preset liquid level value Y is the safe liquid level threshold. The specific values ​​are determined by those skilled in the art based on the actual equipment parameters and operating conditions, and no specific numerical limit is made here.

[0037] Furthermore, the control method also includes: Temperature difference data at each monitoring point is acquired in real time by temperature sensors 80 installed at the inlet and outlet of each monitoring point. When the water pressure of the cooling system remains constant, the cooling water supply of the cooling system is adjusted according to the cooling water temperature difference data and liquid level data.

[0038] By dynamically adjusting the cooling water supply based on a comprehensive assessment of the cooling water temperature difference and liquid level data under constant water pressure, the waste of water resources and energy caused by excessive cooling can be avoided, resulting in greater energy efficiency.

[0039] Furthermore, the logic for this energy-saving regulation and fault early warning is as follows: When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues a command to reduce the cooling water supply and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues a fault warning and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system maintains the current operating state. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system issues a fault warning.

[0040] The principles behind the aforementioned cooling water volume regulation and fault warning are as follows: When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level is greater than the preset liquid level value Y, it indicates that the cooling water supply is too large and the heat exchange efficiency has a margin. At this time, the control system will promptly provide feedback to the customer through the Internet of Things system, which can appropriately reduce the cooling water supply and perform a safety pressure relief operation to remove any air that may have accumulated inside the system, thereby reducing the cooling water volume and achieving energy-saving effects. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level is greater than the preset liquid level value Y, it indicates that the heat exchange is insufficient but there is little air in the system. At this time, the control system will issue a fault warning and perform a safety pressure relief operation to remove the small amount of air that may exist in the system. If the temperature difference is still abnormal after eliminating the air resistance factor, further maintenance will be required. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level is less than the preset liquid level value Y, it indicates that the cooling system is operating normally and can maintain normal operation without adjustment. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level is less than the preset liquid level value Y, it indicates that the heat exchange is seriously insufficient and there may be a large amount of air in the system (a low liquid level means that there is a large space at the top, and air is easy to accumulate). At this time, the control system will issue a fault warning and prompt the system to prioritize the safe pressure relief and discharge operation. If the temperature difference is still abnormal after the discharge is completed, it is necessary to further investigate the heat exchanger blockage or other mechanical faults so that timely maintenance can be carried out to eliminate the fault.

[0041] A large temperature difference in cooling water actually indicates poor heat exchange efficiency. This is because, according to the heat transfer rate equation, the actual rate of heat exchange depends on the heat transfer rate equation:

[0042] Where Q is the heat exchange capacity, K is the overall heat transfer coefficient (reflecting the degree of heat exchange), A is the heat exchange area, and ΔTm is the logarithmic mean temperature difference, which is the average temperature difference between the two fluids. Given a fixed heat exchange capacity Q and a fixed heat exchange area A, the larger K is, the smaller the required ΔTm. Therefore, the smaller the temperature difference of the cooling water, the better the heat exchange effect.

[0043] In the above logic, the preset temperature difference value Z is the cooling water temperature difference threshold. The specific value is determined by those skilled in the art based on the actual equipment parameters and operating conditions. No specific value of the preset temperature difference value Z is limited here.

[0044] Specifically, reducing the cooling water supply involves determining the reduction range based on the difference between the cooling water temperature difference and the preset temperature difference value Z. The operation of the water pumps supplying the cooling system is then controlled according to the water supply volume. The reduction range corresponding to the difference between the cooling water temperature difference and the preset temperature difference value Z can be determined based on industry standards, industry experience, or equipment design parameters. By controlling the speed or operating frequency of the water pumps, the water supply volume is adjusted to match the cooling demand, thus saving energy and water resources.

[0045] To improve the accuracy of water pressure and liquid level detection, the pressure sensor 60 and the liquid level sensor 70 can be positioned at high points at each monitoring point. This ensures accurate detection of air accumulation and the true liquid level at each monitoring point.

[0046] Optionally, fault warnings can be issued through one or more information carriers such as sound, light, and text.

[0047] Because the motor 90 and the frequency converter generate a large amount of heat during operation, heat exchangers are typically installed to cool them down in order to ensure their continuous and stable operation. The refrigerant used in these heat exchangers is usually cooling oil or liquid. The motor 90 and / or the frequency converter require cooling with coolant (oil). A pump draws cold coolant from the storage tank and then sends it to the inlets of each stage of the motor 90 and the frequency converter. The cold coolant carries away the heat from the motor 90 and the frequency converter, becoming hot coolant. This hot coolant then enters the power source heat exchanger 40. After exchanging heat with cooling water in the power source heat exchanger 40, the cold coolant returns to the storage tank. This cycle continues, controlling the temperature of the motor 90 and / or the frequency converter to ensure they always operate at a suitable temperature.

[0048] Optionally, the venting operation includes manually removing the plug at the monitoring point to vent air and / or activating the automatic venting device. Venting can be performed manually or automatically via the automatic venting device, depending on actual needs.

[0049] Alternatively, the automatic exhaust device may be a solenoid valve or other type of electrically controlled valve.

[0050] In one specific embodiment, fault warnings are sent to a remote terminal in real time via an Internet of Things (IoT) system. Users can monitor the operating status of the cooling system through the remote terminal and remotely control the exhaust and adjust the cooling water supply.

[0051] Optionally, the IoT system can connect to remote terminals via Bluetooth, infrared, wired networks, or wireless networks. Remote terminals can be computers, tablets, mobile phones, dedicated controllers, or other similar devices.

[0052] Please refer to the following: Figures 1 to 4 A second aspect of this application is to provide a cooling system for a multi-stage centrifugal compressor for performing any of the methods described above, comprising: Multiple monitoring units are set at multiple monitoring points in the cooling system. Each monitoring unit includes a pressure sensor 60 and a liquid level sensor 70, which are used to acquire water pressure data and liquid level data of the corresponding monitoring point in real time. The control system is connected to each monitoring unit to receive water pressure and liquid level data from each monitoring point, and to determine whether the cooling system meets the exhaust safety conditions based on the water pressure and liquid level data. An exhaust actuator is used to allow exhaust operation when the control system determines that exhaust safety conditions are met, and to prohibit exhaust operation when exhaust safety conditions are not met.

[0053] The cooling system of the multi-stage centrifugal compressor in this application ensures that the exhaust operation is carried out only under safe conditions through the dual judgment logic of pressure sensor 60 and liquid level sensor 70, completely eliminating the risk of personnel injury and equipment damage caused by pressurized operation. The exhaust operation has almost zero safety risk, and can scientifically and intuitively judge the air accumulation status inside the cooling system, reduce blind manual operation, and avoid the equipment getting damp due to cooling water splashing.

[0054] Furthermore, the monitoring unit also includes a temperature sensor 80, used to acquire cooling water temperature difference data at the inlet and outlet of each monitoring point of the cooling system; the control system is also used to adjust the cooling water supply of the cooling system according to the cooling water temperature difference data and liquid level data when the water pressure of the cooling system remains constant. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues a command to reduce the cooling water supply and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues a fault warning and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system maintains the current operating state. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system issues a fault warning.

[0055] By dynamically adjusting the cooling water supply based on a comprehensive judgment of cooling water temperature difference and liquid level data under constant water pressure, the system avoids water and energy waste caused by overcooling, thus saving energy. Furthermore, it can provide early warning of faults based on monitoring data, thereby improving the efficiency of troubleshooting.

[0056] In this embodiment, the centrifugal compressor is a four-stage centrifugal compressor, comprising a primary compressor 100, a secondary compressor 100, a tertiary compressor 100, and a fourth-stage compressor 100. The primary and secondary compressors 100 are driven by a first motor 90, while the tertiary and fourth-stage compressors 100 are driven by a second motor 90. Its working principle is as follows: After the four-stage centrifugal compressor starts, compression begins. Air enters the inlet of the primary compressor 100 through the air filter. After primary compression, it is cooled by the primary intercooler 20 and then enters the inlet of the secondary compressor 100. After secondary compression, it enters the secondary intercooler 20 and then enters the tertiary compressor 100. After tertiary compression, it is cooled by the tertiary intercooler 20 and then enters the inlet of the fourth-stage compressor 100. After tertiary compression, it enters the aftercooler 30 and is finally supplied to the customer.

[0057] Correspondingly, the circulation path of the cooling system is as follows: After the water pump of the circulating water cooling system starts, the cooling water enters the cold water inlet of the centrifuge, and then enters the inlet water separator 10. The inlet water separator 10 sends the cold water to the first-stage intercooler 20, the second-stage intercooler 20, the third-stage intercooler 20, the power source heat exchanger 40, and the aftercooler 30 in parallel. After completing the heat exchange, the cooling water that has absorbed heat returns from the above-mentioned coolers to the outlet water combiner 50 and enters the hot water outlet.

[0058] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cooling system control method for a multi-stage centrifugal compressor, characterized in that, include: Multiple monitoring points are set in the cooling system, including: water inlet water separator (10), at least one intermediate cooler (20), aftercooler (30), power source heat exchanger (40) and water outlet water separator (50), and each monitoring point is equipped with a pressure sensor (60) and a liquid level sensor (70). Real-time acquisition of water pressure and liquid level data at each monitoring point; Determine whether the cooling system meets the exhaust safety conditions based on the water pressure data and the liquid level data; The exhaust safety conditions are: the water pressure data is less than or equal to the preset pressure value X and the liquid level data is greater than or equal to the preset liquid level value Y, or the water pressure data is less than or equal to the preset pressure value X and the liquid level data is less than or equal to the preset liquid level value Y. When the exhaust safety conditions are met, the exhaust operation is permitted; when the exhaust safety conditions are not met, the manual exhaust operation is prohibited, and the automatic exhaust actuator is controlled by the control system to safely release pressure and discharge water. The exhaust operation is completed after the water pressure data is reduced to below the preset pressure value X.

2. The method according to claim 1, characterized in that, Also includes: Temperature difference data of each monitoring point is acquired in real time by temperature sensors (80) installed at the inlet and outlet of each monitoring point. When the water pressure of the cooling system remains constant, the cooling water supply of the cooling system is adjusted according to the cooling water temperature difference data and liquid level data.

3. The method according to claim 2, characterized in that, When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the cooling water supply is reduced and the air inside the system is discharged. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, a fault warning is issued and the air inside the system is discharged. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the current operating state is maintained. A fault warning is issued when the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y.

4. The method according to claim 3, characterized in that, The operation of reducing the cooling water supply is specifically as follows: the reduction range of the cooling water supply is determined according to the difference between the cooling water temperature difference and the preset temperature difference value Z, and the operation of the water pump in the cooling system is controlled according to the water supply.

5. The method according to claim 1, characterized in that, The pressure sensor (60) and the level sensor (70) are located at high positions at each monitoring point.

6. The method according to claim 1, characterized in that, The power source heat exchanger (40) is used to regulate the temperature of the motor (90) and / or the frequency converter.

7. The method according to claim 1, characterized in that, The venting operation includes manually removing the plug at the monitoring point to vent air and / or activating the automatic venting device to vent air.

8. The method according to claim 3, characterized in that, The fault warning is sent to a remote terminal in real time via an Internet of Things (IoT) system.

9. A cooling system for a multi-stage centrifugal compressor, characterized in that, For performing the method as described in any one of claims 1 to 8, comprising: Multiple monitoring units are respectively set at multiple monitoring points of the cooling system. Each monitoring unit includes a pressure sensor (60) and a liquid level sensor (70) for real-time acquisition of water pressure data and liquid level data of the corresponding monitoring point. The control system is communicatively connected to each of the monitoring units and is used to receive water pressure data and liquid level data from each monitoring point, and to determine whether the cooling system meets the exhaust safety conditions based on the water pressure data and liquid level data. The exhaust actuator is used to allow the exhaust operation when the control system determines that the exhaust safety conditions are met, and to prohibit the manual exhaust operation when the exhaust safety conditions are not met. The control system controls the exhaust actuator to safely release pressure and discharge water. The exhaust operation is completed after the water pressure data drops below the preset pressure value X.

10. The system according to claim 9, characterized in that, The monitoring unit also includes a temperature sensor (80) for acquiring the cooling water temperature difference data at the inlet and outlet of each monitoring point of the cooling system; the control system is also used to adjust the cooling water supply of the cooling system according to the cooling water temperature difference data and liquid level data when the water pressure of the cooling system remains constant. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues an instruction to reduce the cooling water supply and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is greater than or equal to the preset liquid level value Y, the control system issues a fault warning and controls the exhaust actuator to safely release pressure and discharge air to remove air from the system. When the cooling water temperature difference is less than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system maintains the current operating state; When the cooling water temperature difference is greater than the preset temperature difference value Z and the liquid level data is less than the preset liquid level value Y, the control system issues a fault warning.

Images