Centrifugal pump anti-freezing device and water circulation cooling system applying same

Abstract

The invention provides a centrifugal pump anti-freezing device and a water circulation cooling system applying the centrifugal pump anti-freezing device, and belongs to the technical field of water circulation cooling systems.The centrifugal pump anti-freezing device comprises a centrifugal pump, a low-pressure fluid cavity, a high-pressure fluid cavity and a backflow assembly, and the low-pressure fluid cavity communicates with the high-pressure fluid cavity through the centrifugal pump. The backflow assembly comprises a control valve, a first backflow pipe and a second backflow pipe, an inlet of the control valve communicates with the high-pressure fluid cavity through the first backflow pipe, and an outlet of the control valve communicates with the outlet end through the second backflow pipe. During operation, the centrifugal pump pumps fluid in the low-pressure fluid cavity into the high-pressure fluid cavity. When the centrifugal pump is in a low-temperature environment and shut down, fluid in the high-pressure fluid cavity flows back into the valve cavity through the backflow assembly under the action of pressure difference, so that the fluid in the valve cavity is in a moving state all the time, and the situation that the impeller is frozen and is difficult to start is avoided. The backflow fluid can automatically flow under the action of the pressure difference between the high-pressure fluid cavity and the low-pressure fluid cavity without additionally arranging power equipment.

Description

Technical Field

[0001] The present application belongs to the technical field of water circulation cooling systems, and more specifically, relates to a centrifugal pump anti-freezing device and a water circulation cooling system using the same. Background Art

[0002] The petrochemical industry's circulating water system is a crucial component for cooling petrochemical equipment. Centrifugal pumps, as a key component of the circulating water system, are the power source for the entire system. Within the system, the cooling pool acts as a low-pressure fluid chamber, while the equipment side acts as a high-pressure fluid chamber, with an internal pressure higher than the cooling pool. The centrifugal pump is responsible for pumping cooled water from the cooling pool to the equipment side, where it is then sent to the cooling tower for cooling before returning to the cooling pool. This cycle continues, exchanging heat and cooling the equipment.

[0003] In some usage scenarios, such as equipment maintenance, or when the ambient temperature drops to a point where the cooling demand can be met without the need for a water circulation system, the centrifugal pump will be in a long-term shutdown state. Alternatively, for the reliability of the equipment, some water circulation systems will install a spare centrifugal pump circuit, which is also in a long-term shutdown state during normal use. For the centrifugal pump in the above-mentioned shutdown state, when encountering cold weather, the residual cooling water inside it will freeze the impeller inside the centrifugal pump, which may make it difficult to start the centrifugal pump or even freeze and crack and be damaged. In order to insulate the centrifugal pump to avoid freezing, the prior art maintains the temperature inside the centrifugal pump by setting up an insulation room or a separate heating system, but this solution is complex and costly. Summary of the Invention

[0004] In order to address the deficiencies of the prior art, the present application provides a centrifugal pump anti-freezing device and a water circulation cooling system using the same, which ensures that the fluid in the valve cavity is always in a flowing state through the reflux fluid, thereby preventing the impeller from freezing and becoming difficult to start.

[0005] To achieve the above-mentioned objectives, the technical solution of the present application provides a centrifugal pump anti-freezing device, comprising a centrifugal pump, a low-pressure fluid chamber, and a high-pressure fluid chamber. The centrifugal pump has a valve body, the valve body having a valve chamber, an inlet end, and an outlet end. An impeller is arranged in the valve chamber, the inlet end is communicated with the low-pressure fluid chamber, the outlet end is communicated with the high-pressure fluid chamber, and an outlet valve is installed between the outlet end and the high-pressure fluid chamber; the centrifugal pump also includes a reflux assembly, the reflux assembly includes a control valve, a reflux pipe 1, and a reflux pipe 2, the inlet of the control valve is communicated with the high-pressure fluid chamber through the reflux pipe 1, and the outlet of the control valve is communicated with the outlet end through the reflux pipe 2;

[0006] During normal operation, the outlet valve is open, the control valve is closed, and the centrifugal pump pumps the fluid in the low-pressure fluid chamber into the high-pressure fluid chamber. In a low-temperature environment and after the centrifugal pump is shut down, the outlet valve is closed and the control valve is opened. The fluid in the high-pressure fluid chamber passes through return pipe 1, the control valve, and return pipe 2 in sequence under its own pressure, and then flows back into the valve chamber through the outlet end, and finally flows back into the low-pressure fluid chamber from the inlet end. The refluxed fluid always remains in a flowing state in the valve chamber, preventing the impeller from being frozen due to shutdown and becoming difficult to start. The refluxed fluid does not need to be driven by additional power equipment, and can flow automatically under the action of the pressure difference between the high-pressure fluid chamber and the low-pressure fluid chamber. The entire centrifugal pump anti-freeze device has a simple structure, does not require the installation of a complex insulation room or heating system, and is highly practical.

[0007] Optionally, an outlet connecting pipe is further included, to which an outlet valve is mounted, and the outlet connecting pipe is divided by the outlet valve into pipe section one and pipe section two, wherein pipe section one is connected to the high-pressure fluid chamber, and pipe section two is connected to the outlet end, and the end of return pipe one away from the control valve is connected to pipe section one, and the end of return pipe two away from the control valve is connected to pipe section two. The outlet valve and the reflux assembly are both connected to the outlet connecting pipe, which can be used as an integral assembly, making it easy to produce and install between the existing high-pressure fluid chamber and the outlet end of the centrifugal pump, facilitating the modification of existing equipment. The outlet connecting pipe can be bent to form different directions as needed, providing greater adaptability.

[0008] Optionally, the outlet connecting pipe is further provided with a check valve, which is located between the outlet valve and the connection between the return pipe 2 and the outlet connecting pipe. The check valve can prevent backflow during operation of the centrifugal pump, and the check valve will not affect the return flow of the fluid along the return assembly during shutdown.

[0009] Optionally, an inlet connecting pipe is further included, through which the low-pressure fluid chamber is connected to the outlet end, and an inlet valve is installed in the middle of the inlet connecting pipe to achieve on-off control between the centrifugal pump and the low-pressure fluid chamber.

[0010] Optionally, the system further includes expansion joint 1, reducer 1, expansion joint 2, and reducer 2. The outlet is sequentially connected to pipe section 2 via reducer 1 and expansion joint 1, and the inlet is sequentially connected to the inlet connecting pipe via reducer 2 and expansion joint 2. In environments with large temperature fluctuations, expansion joints 1 and 2 can compensate for additional stress caused by temperature changes or external vibrations.

[0011] A water circulation cooling system using any of the above-mentioned centrifugal pump anti-freezing devices includes a cooling pipe, a cooling tower and a cooling pool, wherein the cooling pipe serves as the high-pressure fluid chamber, the cooling pool serves as the low-pressure fluid chamber, the end of the cooling pipe away from the centrifugal pump is connected to the inlet of the cooling tower, and the outlet of the cooling tower is connected to the cooling pool.

[0012] The cooling pipe is wrapped around the outside of the equipment that needs cooling. When the system is running, the outlet valve opens, the control valve closes, and the centrifugal pump pumps cooling water from the cooling pool into the cooling pipe to cool the equipment. The cooling water absorbs heat, its temperature rises, and then it is cooled by the cooling tower before returning to the cooling pool to complete a cycle. The pressure in the cooling pipe is greater than the pressure in the cooling pool. When the centrifugal pump is shut down in cold temperatures, the outlet valve is closed and the control valve is opened. The high-pressure fluid in the cooling pipe flows back into the valve cavity along the return assembly due to the pressure difference, keeping the water in the valve cavity in a flowing state, making it more difficult to freeze and preventing the centrifugal pump from being difficult to start due to freezing.

[0013] Optionally, the outlet valve, centrifugal pump, and reflux assembly are combined into a flow unit, which can be arranged in several groups and connected in parallel between the cooling pipe and the cooling pool. Some of these flow units serve as the main operating units and are always open, while the remaining flow units serve as backup units and are generally not operated. For the backup unit, its outlet valve is always closed during normal operation, and the control valve is open. This ensures that fluid always flows back during normal operation to prevent ice from forming in the valve cavity, which could hinder startup due to prolonged non-use. When the main operating unit needs to be shut down due to a fault, the control valve of the backup unit is closed, the outlet valve is opened, and the centrifugal pump is started to operate in place of the main operating unit. During troubleshooting, the outlet valve of the main operating unit is closed and the control valve is opened. This ensures that fluid always flows in the valve cavity of the centrifugal pump in the main operating unit, making it less likely to freeze and reducing the risk of freezing during maintenance and troubleshooting. Since some of the flow units are always in operation, the pressure in the high-pressure fluid chamber is always higher than that in the low-pressure fluid chamber, ensuring that the reflux fluid, driven by the pressure differential, can consistently drive the impeller in the non-operating centrifugal pump.

[0014] The technical solution of this application has the following advantages over the prior art:

[0015] During normal operation, the centrifugal pump pumps the fluid in the low-pressure fluid chamber into the high-pressure fluid chamber. When in a low-temperature environment and the centrifugal pump is shut down, the fluid in the high-pressure fluid chamber passes through return pipe 1, the control valve and return pipe 2 in sequence under its own pressure, and then flows back to the valve chamber through the outlet end, so that the fluid in the valve chamber is always in a flowing state, and finally flows back to the low-pressure fluid chamber from the inlet end. Since flowing fluid is more difficult to freeze than static fluid, it reduces the risk of the impeller being frozen due to shutdown. The reverse reflux fluid does not need to be driven by additional power equipment, and it can flow automatically under the pressure difference between the high-pressure fluid chamber and the low-pressure fluid chamber. The entire centrifugal pump anti-freeze device has a simple structure, does not require the installation of a complex insulation room or heating system, and is highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 This is a schematic diagram of the overall structure of the centrifugal pump anti-freezing device;

[0018] Figure 2 It is a schematic diagram of the connection structure of the centrifugal pump;

[0019] Figure 3 Schematic diagram of the overall structure of the water circulation cooling system.

[0020] Icons: 1. Centrifugal pump; 11. Valve body; 12. Inlet end; 13. Outlet end; 21. Low-pressure fluid chamber; 22. High-pressure fluid chamber; 31. Outlet valve; 32. Check valve; 33. Inlet valve; 41. Control valve; 42. Return pipe 1; 43. Return pipe 2; 5. Outlet connecting pipe; 51. Pipe section 1; 52. Pipe section 2; 6. Inlet connecting pipe; 71. Expansion joint 1; 72. Reducer 1; 73. Expansion joint 2; 74. Reducer 2; 81. Cooling pipe; 82. Cooling tower; 83. Cooling pool; 84. Main operating unit; 85. Spare unit. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0022] Example 1:

[0023] This embodiment provides a centrifugal pump anti-freezing device based on Figure 1 and Figure 2 As shown, it includes a centrifugal pump 1, a low-pressure fluid chamber 21 and a high-pressure fluid chamber 22. The centrifugal pump 1 has a valve body 11, the valve body 11 has a valve chamber, an inlet end 12 and an outlet end 13, an impeller is arranged in the valve chamber, the inlet end 12 is connected to the low-pressure fluid chamber 21, and the outlet end 13 is connected to the high-pressure fluid chamber 22. The internal pressure of the high-pressure fluid chamber 22 is greater than the internal pressure of the low-pressure fluid chamber 21. After the centrifugal pump 1 is started, the liquid in the low-pressure fluid chamber 21 can be pumped into the high-pressure fluid chamber 22. An outlet valve 31 is installed between the outlet end 13 and the high-pressure fluid chamber 22. The outlet valve 31 is open when the centrifugal pump 1 is working normally. When the centrifugal pump 1 is shut down, the outlet valve 31 is closed to isolate the low-pressure fluid chamber 21 and the high-pressure fluid chamber 22 to prevent the liquid from flowing back under the action of the pressure difference.

[0024] When the centrifugal pump 1 is shut down, if low temperatures occur, the residual liquid inside the valve chamber may freeze and freeze the impeller. Therefore, on the basis of the above structure, a reflux component is also provided. The reflux component includes a control valve 41, a reflux pipe 1 42 and a reflux pipe 2 43. The inlet of the control valve 41 is connected to the high-pressure fluid chamber 22 through the reflux pipe 1 42, and the outlet of the control valve 41 is connected to the outlet end 13 through the reflux pipe 2 43. When the centrifugal pump 1 is operating normally, the outlet valve 31 is open, the control valve 41 is closed, the reflux pipe 1 42 and the reflux pipe 2 43 are in a blocked state, and the centrifugal pump 1 pumps the fluid in the low-pressure fluid chamber 21 into the high-pressure fluid chamber 22. When the ambient temperature is higher than the freezing temperature, the control valve 41 is always in a closed state regardless of whether the centrifugal pump 1 is shut down. When the ambient temperature is below freezing and centrifugal pump 1 is shut down, outlet valve 31 closes and control valve 41 opens. Under the influence of the pressure differential, the fluid in high-pressure fluid chamber 22 passes through return pipe 1 42, control valve 41, and return pipe 2 43 in sequence, and then flows back into the valve chamber through outlet port 13. Because there is a certain gap between the impeller and the inner wall of the valve chamber, the returning fluid passes through the gap between the inner wall of the valve chamber and the impeller, and ultimately flows back into low-pressure fluid chamber 21 from inlet port 12, ensuring that the returning fluid remains in a flowing state within the valve chamber.

[0025] Since the fluid flowing back into the valve cavity is always in a flowing state in the valve cavity. At the same temperature, the flowing fluid is more difficult to freeze than the static fluid, which reduces the situation where the impeller is frozen due to shutdown and is difficult to start. The flow rate of the reflux is set to be able to keep the valve cavity from being frozen, that is, the reflux is in a small flow rate. In actual use, the reflux flow rate generally does not exceed 3% of the rated flow rate of the centrifugal pump 1. Specifically in this embodiment, the rated flow rate Q is 10000m 3 Taking a large centrifugal pump 1 with a flow rate of 100 rpm, a head H of 50 meters, and an impeller diameter of 0.91 meters as an example, the pressure in the high-pressure fluid chamber 22 is 50 meters of water column pressure, and the pressure in the low-pressure fluid chamber 21 is atmospheric pressure. For a centrifugal pump antifreeze device, ignoring the flow resistance and local resistance losses along the way, a return flow rate of only 1.38% of the rated flow rate Q is required to prevent the impeller from freezing in environments with temperatures not below -5°C. This smaller return flow rate does not affect the pressure distribution of the entire system. The lower the ambient temperature, the greater the required return flow rate. To adapt to different low-temperature environments, the control valve 41 can be an adjustable flow valve to control the return flow rate, ensuring that the return flow rate is maintained at the minimum value required to prevent the impeller from freezing. The control valve 41 can be manually switched on and off or remotely controlled via a control device such as a PLC controller. The centrifugal pump antifreeze device in this embodiment has a simple structure and can be applied to single-suction or double-suction pumps. It prevents impeller freezing in low-temperature environments without the need for a complex insulation room or heating system, making it highly practical.

[0026] For the large centrifugal pump 1 in this embodiment, the moment of inertia of its impeller can reach 192kg*m 2 The moment of inertia of the rotating parts in the motor of the centrifugal pump 1 can reach 367kg*m 2 The force exerted by the return fluid on the impeller is much smaller than the force required for the impeller and the motor rotating parts to rotate. The impeller in the centrifugal pump 1 will not rotate under the push of the return fluid, and the flow of the return fluid itself can keep the valve cavity from ice.

[0027] Furthermore, it also includes an outlet connecting pipe 5. The outlet connecting pipe 5 serves as a connecting component between the outlet end 13 of the centrifugal pump 1 and the high-pressure fluid chamber 22. The outlet valve 31 is installed on the outlet connecting pipe 5, and the outlet connecting pipe 5 is divided into pipe section 1 51 and pipe section 2 52 by the outlet valve 31. Pipe section 1 51 is connected to the high-pressure fluid chamber 22, and pipe section 2 52 is connected to the outlet end 13. The end of the return pipe 1 42 away from the control valve 41 is connected to pipe section 1 51, and the end of the return pipe 2 43 away from the control valve 41 is connected to pipe section 2 52. In this way, the outlet valve 31 and the reflux component are both connected to the outlet connecting pipe 5, which can be produced and used as an integral component, which is easy to produce and easy to install between the existing high-pressure fluid chamber 22 and the outlet end 13 of the centrifugal pump 1, and is convenient for the modification of existing equipment. The outlet connecting pipe 5 can be bent into different directions according to needs, and has stronger adaptability.

[0028] Furthermore, the outlet connecting pipe 5 is equipped with a check valve 32, located between the outlet valve 31 and the connection point between the return pipe 2 43 and the outlet connecting pipe 5. During normal operation of the centrifugal pump 1, the check valve 32 prevents backflow of fluid pumped into the high-pressure fluid chamber 22, and the position of the check valve 32 does not affect the backflow of fluid along the return assembly during shutdown. The centrifugal pump 1 also includes an inlet connecting pipe 6. The inlet connecting pipe 6 serves as a connecting component between the inlet end 12 and the low-pressure fluid chamber 21 of the centrifugal pump 1. The low-pressure fluid chamber 21 is connected to the outlet end 13 via the inlet connecting pipe 6. An inlet valve 33 is installed in the middle of the inlet connecting pipe 6. In this embodiment, both the inlet valve 33 and the outlet valve 31 are butterfly valves. During normal operation of the centrifugal pump 1, the inlet valve 33 is open, allowing the centrifugal pump 1 to pump out the fluid from the low-pressure fluid chamber 21. When the centrifugal pump 1 is shut down and the ambient temperature is above freezing, the inlet valve 33 can be closed because there is no need to open the control valve 41 to allow fluid backflow. When centrifugal pump 1 is shut down and the ambient temperature is below freezing, inlet valve 33 needs to be opened, allowing fluid flowing back into the valve chamber to flow back into low-pressure fluid chamber 21 through inlet connecting pipe 6. Furthermore, the pump includes expansion joint 1 71, reducer 1 72, expansion joint 2 73, and reducer 2 74. Outlet end 13 is sequentially connected to pipe section 2 52 via reducer 1 72 and expansion joint 1 71, while inlet end 12 is sequentially connected to inlet connecting pipe 6 via reducer 2 74 and expansion joint 2 73. Reducer 1 72 and reducer 2 74 serve as transitional connection components. Reducer 1 72 connects expansion joint 1 71 to outlet end 13, whose cross-sectional shape differs from that of the end of expansion joint 1 71. Reducer 2 74 connects expansion joint 2 73 to inlet end 12, whose cross-sectional shape differs from that of the end of expansion joint 2 73. In environments with large temperature fluctuations, expansion joint 1 71 and expansion joint 2 73 can compensate for additional stress caused by temperature changes or external vibrations.

[0029] Example 2:

[0030] This embodiment provides a water circulation cooling system using the centrifugal pump anti-freezing device shown in Example 1. Figures 1 to 3 As shown, it includes a cooling pipe 81, a cooling tower 82 and a cooling pool 83. The cooling pipe 81 serves as the high-pressure fluid chamber 22, and the cooling pool 83 serves as the low-pressure fluid chamber 21. The end of the cooling pipe 81 away from the centrifugal pump 1 is connected to the inlet of the cooling tower 82, and the outlet of the cooling tower 82 is connected to the cooling pool 83.

[0031] The cooling pipe 81 is wound around the outside of the equipment that needs to be cooled. When the system is running, the centrifugal pump 1 pumps the cooling water in the cooling pool 83 into the cooling pipe 81 to cool the equipment. After the cooling water absorbs heat and its temperature rises, it is cooled by the cooling tower 82 and then flows back to the cooling pool 83 to complete a cycle. During actual use, the pressure in the cooling pipe 81 is greater than the pressure in the cooling pool 83. When the centrifugal pump 1 is shut down at a cold temperature, the outlet valve 31 is closed and the control valve 41 is opened. Under the action of the pressure difference, the high-pressure fluid in the cooling pipe 81 flows back to the valve cavity along the reflux component in a small flow rate, and then flows back to the cooling pool 83. The water in the valve cavity is always in a flowing state to prevent the centrifugal pump 1 from being difficult to start due to freezing. The water circulation cooling system can be used in circulating water projects in petrochemicals to cool related equipment.

[0032] Further, based on Figure 3 As shown, the outlet valve 31, the centrifugal pump 1 and the reflux component are combined into a circulation unit. The circulation unit has several groups, and the several groups of circulation units are connected in parallel between the cooling pipe 81 and the cooling pool 83. The circulation unit can be set to six or eight groups, etc., and the number depends on the scale of the system. The inlet end 12 of the centrifugal pump 1 in each group of circulation units is connected to the cooling pool 83, and the outlet end 13 is connected to the cooling pipe 81 through the outlet valve 31. Some of the circulation units are always open as the main operating units 84, while the remaining circulation units are generally not opened for operation as backup units 85. For example, in this embodiment, there are six groups of circulation units in the water circulation cooling system, of which four groups of circulation units are used as the main operating units 84, and the other two groups of circulation units are used as backup units 85. When a main operating unit 84 needs to be shut down due to a fault, the backup unit 85 can be started to replace the main operating unit 84 to ensure the continuous operation of the water circulation cooling system.

[0033] For the backup unit 85, its outlet valve 31 is always in a closed state under normal operation. When the ambient temperature is higher than the freezing temperature, the control valve 41 of the backup unit 85 can be kept closed. When the ambient temperature is lower than the freezing temperature, the control valve 41 of the backup unit 85 is opened, so that the backup unit 85 always has fluid reflux into the valve cavity during normal operation, ensuring the flow of water in the valve cavity and preventing the impeller from freezing and being difficult to start. Since the reflux flow rate is much smaller than the flow rate pumped from the cooling pool 83 into the cooling pipe 81 in the system, the pressure in the cooling pipe 81 will always be higher than that in the cooling pool 83, and will not affect the operation of the entire water circulation cooling system.

[0034] When the main operating unit 84 needs to be shut down due to a fault, the control valve 41 of the backup unit 85 is closed and the outlet valve 31 is opened, and the centrifugal pump 1 is started to operate to replace the main operating unit 84. The main operating unit 84 closes the outlet valve 31 during the troubleshooting process. If the ambient temperature is below the freezing point, the control valve 41 can be opened during the troubleshooting process, and there is always fluid flowing in the valve chamber of the centrifugal pump 1 in the main operating unit 84 to avoid freezing during the inspection and troubleshooting process. If the centrifugal pump 1 needs to be replaced or disassembled to inspect the inside, the outlet valve 31, control valve 41 and inlet valve 33 can all be closed. At this time, the centrifugal pump 1 is isolated from the high-pressure fluid chamber 22 and the low-pressure fluid chamber 21, and the centrifugal pump 1 can be removed and opened.

[0035] For each group of flow units in this embodiment, Figure 1 and Figure 2 The structure of the centrifugal pump 1 is that the inlet end 12 is connected to the cooling pool 83 in sequence through the reducer 2 74, the expansion joint 2 73 and the inlet connecting pipe 6 with the inlet valve 33 installed in the middle, and the outlet end 13 of the centrifugal pump 1 is connected to the cooling pipe 81 in sequence through the reducer 1 72, the expansion joint 1 71 and the outlet connecting pipe 5, and the connection method of the reflux assembly, the outlet valve 31 and the check valve 32 on the outlet connecting pipe 5 is the same as that in Example 1 and will not be repeated.

[0036] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A centrifugal pump antifreeze device, comprising a centrifugal pump, a low-pressure fluid chamber, and a high-pressure fluid chamber. The centrifugal pump has a valve body, the valve body having a valve chamber, an inlet end, and an outlet end. An impeller is disposed within the valve chamber. The inlet end communicates with the low-pressure fluid chamber, the outlet end communicates with the high-pressure fluid chamber, and an outlet valve is installed between the outlet end and the high-pressure fluid chamber. Its characteristics are: The device further comprises a reflux assembly, the reflux assembly comprising a control valve, a first reflux pipe, and a second reflux pipe, wherein the inlet of the control valve is connected to the high-pressure fluid chamber through the first reflux pipe, and the outlet of the control valve is connected to the outlet end through the second reflux pipe; After the centrifugal pump is shut down, the outlet valve is closed and the control valve is opened. The fluid in the high-pressure fluid chamber passes through the return pipe 1, the control valve and the return pipe 2 in sequence, then flows back to the valve chamber through the outlet end, and finally flows back to the low-pressure fluid chamber from the inlet end.

2. The anti-freezing device for a centrifugal pump according to claim 1, characterized in that: It also includes an outlet connecting pipe, the outlet valve is installed on the outlet connecting pipe, and the outlet connecting pipe is divided into pipe section one and pipe section two by the outlet valve, the pipe section one is connected to the high-pressure fluid chamber, the pipe section two is connected to the outlet end, the end of the return pipe one away from the control valve is connected to the pipe section one, and the end of the return pipe two away from the control valve is connected to the pipe section two.

3. The anti-freezing device for a centrifugal pump according to claim 2, characterized in that: The outlet communicating pipe is further provided with a check valve, which is located between the outlet valve and the connection between the return pipe 2 and the outlet communicating pipe.

4. The anti-freezing device for a centrifugal pump according to claim 2, characterized in that: It also includes an inlet communicating pipe, through which the low-pressure fluid chamber is communicated with the outlet end, and an inlet valve is installed in the middle of the inlet communicating pipe.

5. The anti-freezing device for a centrifugal pump according to claim 4, characterized in that: It also includes expansion joint 1, reducer 1, expansion joint 2 and reducer 2. The outlet end is connected to the pipe section 2 through the reducer 1 and the expansion joint 1 in sequence, and the inlet end is connected to the inlet connecting pipe through the reducer 2 and the expansion joint 2 in sequence.

6. A water circulation cooling system using the centrifugal pump anti-freezing device according to any one of claims 1 to 5, characterized in that: It includes a cooling pipe, a cooling tower and a cooling pool. The interior of the cooling pipe serves as the high-pressure fluid chamber, the interior of the cooling pool serves as the low-pressure fluid chamber, the end of the cooling pipe away from the centrifugal pump is connected to the inlet of the cooling tower, and the outlet of the cooling tower is connected to the cooling pool.

7. The water circulation cooling system according to claim 6, characterized in that: The outlet valve, the centrifugal pump and the reflux component are combined into a circulation unit. The circulation unit has several groups. The groups of circulation units are connected in parallel and communicated between the cooling pipe and the cooling pool.

Images