A cooling water system for emergency diesel generator sets in nuclear power plants

Abstract

The present invention relates to a cooling water system for an emergency diesel generator set for a nuclear power plant, comprising a diesel engine, and a cylinder area and an intercooler area arranged in the diesel engine; the cylinder area and the intercooler area are both provided with corresponding water inlet pipes and water outlet pipes, and corresponding water inlet pumps are provided on the respective water inlet pipes; the water inlet pumps are respectively connected with a water replenishment unit and an expansion water tank for replenishing water; and further comprising a radiator unit, the radiator unit is simultaneously connected with the water inlet pipe and the water outlet pipe, and cools the cylinder area and the intercooler area respectively; the pipe connected to the radiator unit and the water inlet pipe is connected to the expansion water tank to synchronously realize the water replenishment and cooling functions. The present invention has a compact and reasonable structure and is easy to operate. By simplifying the system layout, a circulating cooling system of low-temperature water and high-temperature water is simultaneously realized, and the low-temperature water pipe is divided into two paths after the low-temperature water inlet pump, and one pipeline is used to cool the lubricating oil and fuel oil by flowing through the lubricating oil cooler and the fuel oil return cooler.

Description

Technical Field

[0001] The invention relates to the technical field of diesel generator sets in nuclear power plants, in particular to a cooling water system for emergency diesel generator sets in nuclear power plants. Background Art

[0002] The safety of nuclear power plants is a major issue related to people's livelihood and international influence. Therefore, avoiding accidents is an important part of safety design. Among them, nuclear emergency diesel generator sets as backup power sources are one of the important links in the safety system.

[0003] Nuclear power emergency diesel generators are important equipment that protects related equipment from damage and ensures safe shutdown of nuclear power units when a major failure occurs in a nuclear power plant. Generally, the performance requirements for nuclear power emergency diesel generator sets are very high. It is necessary to ensure that the diesel engine is always in hot standby state. The nuclear power emergency diesel engine needs to start quickly within 15 seconds and keep the generator set at a stable operating voltage and frequency. The diesel engine cooling water system can ensure that the operating temperature of the heated parts does not exceed the limit allowed by the material, so that the moving parts of the diesel engine remain in normal working condition, thereby ensuring the reliable operation of the emergency diesel generator set.

[0004] In the existing design of cooling water system for nuclear power emergency diesel generator sets, water replenishment unit and expansion water tank are usually placed on high floors, which is not conducive to water replenishment, discharge and collection of cooling water system. Preheating unit, lubricating oil cooler, fuel return oil cooler, temperature regulating valve and other equipment are relatively scattered in the plant layout and cannot be modularized, which is not conducive to the layout and installation of cooling water system.

[0005] Some cooling water system designs connect the lubricating oil cooler in series with the low-temperature water pipeline. The temperature of the low-temperature water of some models of diesel engines after passing through the lubricating oil cooler cannot be air-cooled in the intercooler. The only way to reduce the low-temperature water temperature is to increase the power of the air-cooled radiator, which greatly increases the cost.

[0006] For this reason, we propose a cooling water system for emergency diesel generator sets in nuclear power plants. Summary of the invention

[0007] In view of the shortcomings of the above-mentioned existing production technology, the applicant provides a cooling water system for emergency diesel generator sets for nuclear power plants, thereby simplifying the system layout and realizing a circulating cooling system of low-temperature water and high-temperature water at the same time.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A cooling water system for an emergency diesel generator set for a nuclear power plant, comprising a diesel engine, and a cylinder area and an intercooler area arranged in the diesel engine;

[0010] The cylinder area and the intercooler area are both provided with corresponding water inlet pipes and water outlet pipes, and corresponding water inlet pumps are provided on the respective water inlet pipes;

[0011] The water inlet pumps of the cylinder area and the intercooler area are respectively connected to a water replenishment unit and an expansion water tank for replenishing water;

[0012] It also includes a radiator unit, which is connected to the water inlet pipe and the water outlet pipe of the cylinder area and the intercooler area at the same time to cool the cylinder area and the intercooler area respectively;

[0013] The pipes connecting the radiator unit to the water inlet pipes of the cylinder area and the intercooler area are connected to the expansion water tank to simultaneously realize the water replenishment and cooling functions;

[0014] The water outlet pipes of the cylinder area and the intercooler area are connected with a temperature control three-way valve, and the three channels of the temperature control three-way valve are respectively connected to the water outlet pipe, water inlet pipe and radiator unit of the cylinder area and the intercooler area;

[0015] The water outlet pipe located on the cylinder area is connected to a first check valve and a preheating unit for preheating the diesel engine in parallel at a section before the temperature control three-way valve;

[0016] The water inlet pump located on the intercooler area is also provided with a bypass pipeline, and the bypass pipeline is connected to the lubricating oil cooler and the fuel return oil cooler pipeline arranged in parallel;

[0017] The water replenishment unit comprises a water replenishment tank and a water replenishment pump for replenishing water into the diesel engine.

[0018] It is further characterized by:

[0019] The cylinder area is provided with a plurality of cylinder assemblies connected in parallel, and high-temperature water inlet pipes and high-temperature water outlet pipes corresponding to the plurality of cylinder assemblies are provided, a high-temperature water inlet pump is provided on the high-temperature water inlet pipe, and the high-temperature water inlet pump is respectively connected to a water replenishment unit and an expansion water tank for replenishing water;

[0020] A first stop valve is provided at the connection between the water replenishment unit and the high-temperature water inlet pipe to control the flow rate, and a first butterfly valve is provided at the connection between the expansion water tank and the high-temperature water inlet pipe to control the flow rate.

[0021] The intercooler area is provided with a plurality of parallel intercooler assemblies, and is provided with low-temperature water inlet pipes and low-temperature water outlet pipes corresponding to the plurality of cylinder assemblies, a low-temperature water inlet pump is provided on the low-temperature water inlet pipe, and the low-temperature water inlet pump is respectively connected to a water replenishment unit and an expansion water tank for replenishing water;

[0022] A second stop valve is provided at the connection between the water replenishment unit and the low-temperature water inlet pipe to control the flow rate, and a second butterfly valve is provided at the connection between the expansion water tank and the low-temperature water inlet pipe to control the flow rate.

[0023] The radiator unit comprises two radiator assemblies which are connected in parallel and are used for cooling the cylinder area and the intercooler area respectively.

[0024] The radiator unit is connected to the water inlet end of the high-temperature water inlet pipe and the water outlet end of the high-temperature water outlet pipe to form a high-temperature water circulation channel; the radiator unit is connected to the water inlet end of the low-temperature water inlet pipe and the water outlet end of the low-temperature water outlet pipe to form a low-temperature water circulation channel.

[0025] The water supply unit is arranged below the diesel engine, a first ball valve is arranged on the water inlet pipe of the water supply tank, and a filter and a fourth ball valve are connected between the water supply pump and the water supply tank;

[0026] The water outlet pipe of the water supply pump is connected to the diesel engine and the water supply tank respectively, a second check valve is arranged on the main pipe of the water outlet pipe of the water supply pump, a second ball valve is arranged on the connecting pipe between the water outlet pipe of the water supply pump and the water supply tank, and a third ball valve is arranged on the connecting pipe between the water outlet pipe of the water supply pump and the diesel engine, respectively controlling the opening and closing and flow of each pipe;

[0027] The water replenishment tank is also provided with a water replenishment tank dosing port, a water replenishment tank vent, a liquid level gauge for detecting the liquid level, and a drain pipe, and the drain pipe is provided with a third stop valve.

[0028] The top of the expansion water tank is also provided with an expansion water tank exhaust port to ensure the internal pressure of the expansion water tank. The expansion water tank is equipped with an expansion water tank level gauge for detecting the water level. The expansion water tank is also provided with an expansion water tank water replenishment port for temporary water replenishment, and the expansion water tank water replenishment port is connected to the water replenishment tank.

[0029] The high-temperature water outlet pipe is located at the highest position and is provided with a high-temperature water exhaust valve, the low-temperature water outlet pipe is located at the highest position and is provided with a low-temperature water exhaust valve, and a throttling orifice plate is provided on the connecting pipe between the temperature control three-way valve on the cylinder area and the intercooler area and the water inlet pipe of the cylinder area and the intercooler area.

[0030] The preheating unit includes a pre-supply water pump and a standby pre-supply water pump connected in parallel, and an electric heater and a lubricating oil heat exchanger connected to the pre-supply water pump and the standby pre-supply water pump. The pre-supply water pump and the standby pre-supply water pump are respectively provided with a third check valve and a fourth check valve.

[0031] A first throttling orifice is provided on the pipeline connecting the water inlet pump in the intercooler area with the lubricating oil cooler and the fuel return oil cooler arranged in parallel, a second throttling orifice is provided on the fuel return oil cooler pipeline, and the parallel pipelines of the lubricating oil cooler and the fuel return oil cooler are also connected to the water outlet pipe before the temperature control three-way valve located in the intercooler area.

[0032] The beneficial effects of the present invention are as follows:

[0033] The present invention has a compact and reasonable structure and is easy to operate. By simplifying the system layout, a circulating cooling system of low-temperature water and high-temperature water is realized at the same time. At the same time, the low-temperature water pipeline is divided into two paths after the low-temperature water inlet pump. One pipeline is used to flow through the lubricating oil cooler and the fuel return oil cooler to cool the lubricating oil and fuel. The water replenishment unit is arranged at the lower layer of the diesel engine to facilitate the collection of cooling water in the system. The water replenishment unit can realize the full mixing function of cooling water and additives. The preheating unit, temperature control valve, lubricating oil cooler, and fuel return oil cooler are integrated in the internal circulation unit, which is convenient for on-site installation and maintenance of the system. At the same time, for diesel engines that do not have a preheating water interface, the arrangement of the preheating unit can preheat the diesel engine cooling water in a small cycle.

[0034] At the same time, the present invention also has the following advantages:

[0035] (1) The pipe connecting the radiator unit to the high-temperature water inlet pipe is also connected to the expansion water tank, which can cool and replenish the water in the cylinder area and discharge the excess gas in the pipe. The pipe connecting the radiator unit to the low-temperature water inlet pipe is also connected to the expansion water tank, which can cool and replenish the water in the intercooler area and discharge the excess gas in the pipe.

[0036] (2) Add the required additives to the cooling water from the dosing port of the water supply tank. At this time, close the third ball valve, open the second ball valve, and turn on the water supply pump to circulate the cooling water between the water supply tank and the pipeline to fully mix the cooling water and the additives to complete the dosing process;

[0037] (3) Through the temperature control of the temperature-controlled three-way valve, the different flow directions of water are determined according to different water temperatures, realizing the switching between small circulation and large circulation, thereby improving the heat dissipation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the cooling water system flow of the present invention.

[0039] Figure 2 It is a schematic diagram of the preheating unit process of the present invention.

[0040] Figure 3 It is a schematic diagram of the water replenishment unit process of the present invention.

[0041] in:

[0042] 1. Diesel engine; 2. Internal circulation unit; 3. Preheating unit; 4. Radiator unit; 5. Expansion water tank; 6. Water supply unit; 7. High-temperature water inlet pump; 8. Low-temperature water inlet pump; 9. High-temperature water exhaust valve; 10. Low-temperature water exhaust valve; 11. Lubricating oil cooler; 12. Fuel return oil cooler; 13. First throttle orifice plate; 14. Second throttle orifice plate; 15. High-temperature water temperature control valve; 16. Low-temperature water temperature control valve; 17. First stop valve; 18. Second stop valve; 19. First check valve; 20. Fourth butterfly valve; 21. First butterfly valve; 22. Third butterfly valve; 23. Second butterfly valve; 24. Expansion water tank exhaust port; 25. Expansion water tank water supply port; 26. Expansion water tank level gauge; 27. Third throttle orifice plate; 28. Fourth throttle orifice plate;

[0043] 101. Cylinder area; 102. Intercooler area

[0044] 301, pre-supply water pump; 302, standby pre-supply water pump; 303, third check valve; 304, fourth check valve; 305, lubricating oil heat exchanger; 306, electric heater;

[0045] 601, water supply tank; 602, liquid level meter; 603, first ball valve; 604, water supply tank dosing port; 605, water supply tank vent; 606, second ball valve; 607, third ball valve; 608, second check valve; 609, water supply pump; 610, filter; 611, fourth ball valve; 612, third stop valve. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0047] like Figure 1-Figure 3 As shown, this embodiment discloses a cooling water system for an emergency diesel generator set for a nuclear power plant, comprising:

[0048] A diesel engine 1, the structure of the diesel engine 1 includes a cylinder area 101 and an intercooler area 102;

[0049] A plurality of groups of cylinder assemblies connected in parallel are arranged in the cylinder area 101, and high-temperature water inlet pipes and high-temperature water outlet pipes corresponding to the plurality of groups of cylinder assemblies are arranged. A high-temperature water inlet pump 7 is arranged on the high-temperature water inlet pipe, and the high-temperature water inlet pump 7 is respectively connected to a water replenishment unit 6 and an expansion water tank 5 for replenishing water. A first stop valve 17 is arranged at the connection between the water replenishment unit 6 and the high-temperature water inlet pipe to control the flow rate, and a first butterfly valve 21 is arranged at the connection between the expansion water tank 5 and the high-temperature water inlet pipe to control the flow rate;

[0050] A plurality of parallel intercooler assemblies are arranged in the intercooler area 102, and low-temperature water inlet pipes and low-temperature water outlet pipes corresponding to the plurality of cylinder assemblies are arranged. A low-temperature water inlet pump 8 is arranged on the low-temperature water inlet pipe, and the low-temperature water inlet pump 8 is respectively connected to a water replenishment unit 6 and an expansion water tank 5 for replenishing water. A second stop valve 18 is arranged at the connection between the water replenishment unit 6 and the low-temperature water inlet pipe to control the flow rate, and a second butterfly valve 23 is arranged at the connection between the expansion water tank 5 and the low-temperature water inlet pipe to control the flow rate;

[0051] This embodiment also includes a radiator unit 4 for cooling the cylinder area 101 and the intercooler area 102. The radiator unit 4 includes two radiator assemblies that are distributed in parallel and dissipate heat for the cylinder area 101 and the intercooler area 102 respectively.

[0052] The radiator unit 4 is connected to the water inlet end of the high-temperature water inlet pipe and the water outlet end of the high-temperature water outlet pipe to form a high-temperature water circulation channel;

[0053] The radiator unit 4 is connected to the water inlet end of the low-temperature water inlet pipe and the water outlet end of the low-temperature water outlet pipe to form a low-temperature water circulation channel;

[0054] At the same time, in this embodiment, the pipe connecting the radiator unit 4 and the high-temperature water inlet pipe is also connected to the expansion water tank 5, so as to realize the cooling and water replenishment functions of the water in the cylinder area 101, and discharge the excess gas in the pipe.

[0055] The pipe connecting the radiator unit 4 and the low-temperature water inlet pipe is also connected to the expansion water tank 5 to realize the cooling and water replenishment functions of the water in the intercooler area 102, and also to discharge the excess gas in the pipe.

[0056] The water replenishment unit 6 is arranged below the diesel engine 1. The water replenishment unit 6 includes a water replenishment tank 601 and a water replenishment pump 609 for replenishing water into the diesel engine 1. A first ball valve 603 is provided on the water inlet pipe of the water replenishment tank 601. A filter 610 and a fourth ball valve 611 are connected between the water replenishment pump 609 and the water replenishment tank 601 to filter water and reduce impurities.

[0057] The water outlet pipe of the water supply pump 609 is provided with connecting pipes to the diesel engine 1 and the water supply tank 601 respectively;

[0058] A second check valve 608 is provided on the main pipe of the water outlet pipe of the water supply pump 609. At the same time, a second ball valve 606 is provided on the connecting pipe between the water outlet pipe of the water supply pump 609 and the water supply tank 601, and a third ball valve 607 is provided on the connecting pipe between the water outlet pipe of the water supply pump 609 and the diesel engine 1, which respectively control the opening and closing and flow rate of each pipeline.

[0059] At the same time, the water replenishment tank 601 is provided with a water replenishment tank dosing port 604, a water replenishment tank vent port 605, a liquid level meter 602 for detecting the liquid level, and a drain pipe, and a third stop valve 612 is provided on the drain pipe.

[0060] It is used to mix cooling water and additives. When adding water for the first time or replenishing water, the cooling water is sent into the system through the replenishing water pump 609. If the cooling water needs to be drained when the system is under maintenance, the replenishing water tank 601 can collect all the cooling water.

[0061] The top of the expansion water tank 5 is also provided with an expansion water tank exhaust port 24 for ensuring the internal pressure of the expansion water tank. The expansion water tank 5 is equipped with an expansion water tank level gauge 26 for detecting the water level. The expansion water tank 5 is provided with an expansion water tank water replenishment port 25 for temporary water replenishment. The expansion water tank water replenishment port 25 is connected to the water replenishment tank 601. The expansion water tank 5 has two pipes respectively connected to the main outlet pipe of the radiator unit 4, which are respectively used for degassing and replenishing high-temperature water and low-temperature water.

[0062] At the same time, the high-temperature water exhaust valve 9 at the highest point of the high-temperature water outlet pipe is connected to the first check valve 19 and the preheating unit 3 arranged in parallel. The preheating unit 3 can preheat the high-temperature water to ensure that the diesel engine 1 always maintains a hot standby state;

[0063] The preheating unit 3 includes a pre-supply water pump 301 and a standby pre-supply water pump 302 connected in parallel, and an electric heater 306 and a lubricating oil heat exchanger 305 connected to the two water pump pipelines; the pre-supply water pump 301 and the standby pre-supply water pump 302 are respectively provided with a third check valve 303 and a fourth check valve 304;

[0064] Two water pumps are arranged in the preheating unit 3, which serve as one for use and one for backup. The cooling water enters the electric heater 306 for heating through the pre-supply water pump 301, then enters the lubricating oil heat exchanger 305 to heat the lubricating oil, and then enters the high-temperature water outlet pipe to achieve the preheating function of the cooling water and the lubricating oil.

[0065] The high-temperature water outlet pipe is located at the rear end of the parallel first check valve 19 and the preheating unit 3 and is connected with a high-temperature water temperature control valve 15. The high-temperature water temperature control valve 15 is a temperature control three-way valve, and the high-temperature water temperature control valve 15 is provided with three interfaces A, B and C. A is connected to the high-temperature water outlet pipe, B is connected to the radiator unit 4, and C is connected to the high-temperature water inlet pipe. A fourth butterfly valve 20 is provided on the connecting pipe between B and the radiator unit 4, and a third throttling orifice plate 27 is provided on the connecting pipe between C and the high-temperature water inlet pipe.

[0066] In this embodiment, the low-temperature water inlet pump 8 not only pumps water for the multiple intercooler assemblies, but also has a bypass pipe connected to the lubricating oil cooler 11 and the fuel return oil cooler 12 arranged in parallel, for cooling the lubricating oil cooler 11 and the fuel return oil cooler 12. The pipes of the lubricating oil cooler 11 and the fuel return oil cooler 12 arranged in parallel are also connected to the low-temperature water outlet pipe.

[0067] Through the temperature control of the temperature-controlled three-way valve, the different flow directions of water are determined according to different water temperatures, realizing the switching between small circulation and large circulation, thereby improving the heat dissipation efficiency.

[0068] A first throttling orifice 13 is provided on the pipeline connecting the low-temperature water inlet pump 8 with the lubricating oil cooler 11 and the fuel return cooler 12 arranged in parallel, and a second throttling orifice 14 is provided on the fuel return cooler 12 pipeline. The flow of each pipeline can be controlled by the first throttling orifice 13 and the fuel return cooler 12.

[0069] The low-temperature water outlet pipe is located at the highest position and is provided with a low-temperature water exhaust valve 10. The low-temperature water outlet pipe is located at the rear end of the lubricating oil cooler 11 and the fuel return oil cooler 12 and is connected with a low-temperature water temperature control valve 16. The low-temperature water temperature control valve 16 is a temperature control three-way valve, and the low-temperature water temperature control valve 16 is provided with three interfaces D, E and F. D is connected to the low-temperature water outlet pipe, E is connected to the radiator unit 4, and F is connected to the low-temperature water inlet pipe. A third butterfly valve 22 is provided on the connecting pipe between E and the radiator unit 4, and a fourth throttling orifice plate 28 is provided on the connecting pipe between F and the low-temperature water inlet pipe.

[0070] The high-temperature water temperature control valve 15 and the low-temperature water temperature control valve 16 are both controlled and adjusted by temperature. When the temperature is lower than the set value, the high-temperature water outlet pipe is connected to the high-temperature water inlet pipe to form a high-temperature water internal circulation, and the low-temperature water outlet pipe is connected to the low-temperature water inlet pipe to form a low-temperature water internal circulation;

[0071] The high-temperature water internal circulation and the low-temperature water internal circulation form an internal circulation unit 2. At the same time, the preheating unit 3, the lubricating oil cooler 11, and the fuel return oil cooler 12 are also integrated in one internal circulation unit 2.

[0072] When the temperature is higher than the set value, the high-temperature water outlet pipe and the low-temperature water outlet pipe are both connected to the radiator unit 4 for heat dissipation.

[0073] The external interface of the internal circulation unit 2 is equipped with four butterfly valves, which are used to isolate the internal circulation unit 2 from the radiator unit 4 during installation and system maintenance.

[0074] The specific working principle is as follows:

[0075] Combination Figures 1 to 3As shown, the first ball valve 603 is kept in a normally open state, the desalted water in the plant is used to fill the water supply tank 601, and the additives required for cooling water are added from the water supply tank dosing port 604. At this time, the third ball valve 607 is closed, the second ball valve 606 is opened, and the water supply pump 609 is turned on to allow the cooling water to circulate between the water supply tank 601 and the pipeline, fully mix the cooling water and the additive, and complete the dosing process;

[0076] Close the second ball valve 606, open the third ball valve 607, open the first stop valve 17, the second stop valve 18, and pump the fully mixed cooling water in the make-up water tank 601 into the high-temperature water inlet pipe, the low-temperature water inlet pipe and the expansion water tank 5 through the make-up water pump 609, until the expansion water tank 5 reaches the high liquid level and then the make-up water pump 609 is stopped.

[0077] At the same time, the water inlet and outlet of the preheating unit 3 are respectively arranged at both ends of the first check valve 19. When the diesel engine 1 is in the preheating stage, the preheating unit 3 pumps the high-temperature inlet water into the electric heater 306 for heating. The heated high-temperature water enters the lubricating oil heat exchanger 305 to preheat the lubricating oil. The preheated high-temperature water flows through the C side of the high-temperature water temperature control valve 15 and the third throttle orifice plate 27 to enter the diesel engine 1, forming a preheating cycle. When the pre-supply water pump 301 fails, the standby pre-supply water pump 302 works to ensure that the high-temperature water always reaches the preheating temperature.

[0078] When the diesel engine 1 is working, the preheating unit 3 stops working, and the high-temperature water inlet pump 7 pumps high-temperature water into the diesel engine 1 to cool the cylinder head, cylinder liner and other components. The high-temperature water passes through the first check valve 19 and reaches the high-temperature water temperature control valve 15. When the high-temperature water temperature is lower than the minimum value set by the high-temperature water temperature control valve 15, the valve core of the high-temperature water temperature control valve 15 rotates to the small circulation position, and all the high-temperature water flows from the A side of the high-temperature water temperature control valve 15 to the C side, completing a closed small circulation.

[0079] When the high-temperature water temperature is greater than the minimum value set by the high-temperature water temperature control valve 15, the valve core opening of the high-temperature water temperature control valve 15 changes with the increase of water temperature, from a small cycle to a large cycle, until the water temperature reaches the maximum value set by the high-temperature water temperature control valve 15 and is in the large cycle position. The high-temperature water flows from the A side of the high-temperature water temperature control valve 15 to the B side, and then flows to the radiator unit 4, and returns to the inlet of the high-temperature water inlet pump 7 after heat dissipation and cooling, completing a closed large cycle.

[0080] At the same time, the low-temperature water inlet pump 8 pumps one path of low-temperature water into the intercooler in the diesel engine 1 and then reaches the low-temperature water temperature control valve 16, and the other path of low-temperature water passes through the first throttle orifice plate 13 and the second throttle orifice plate 14 and enters the lubricating oil cooler 11 and the fuel return oil cooler 12 respectively. When the low-temperature water temperature is lower than the lowest value set by the low-temperature water temperature control valve 16, the valve core of the low-temperature water temperature control valve 16 rotates to the small circulation position, and all the low-temperature water flows from the A side of the low-temperature water temperature control valve 16 to the F side, completing a closed small circulation;

[0081] When the low-temperature water temperature is greater than the minimum value set by the low-temperature water temperature control valve 16, the valve core opening of the low-temperature water temperature control valve 16 changes with the increase of water temperature, from a small cycle to a large cycle, until the water temperature reaches the maximum value set by the low-temperature water temperature control valve 16 and is in the large cycle position, the low-temperature water all flows from the A side of the low-temperature water temperature control valve 16 to the E side, and then flows to the radiator unit 4, and returns to the inlet of the low-temperature water inlet pump 8 after heat dissipation and cooling, completing a closed large cycle.

[0082] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A cooling water system for emergency diesel generator sets for nuclear power plants, characterized in that: It comprises a diesel engine (1), and a cylinder area (101) and an intercooler area (102) arranged in the diesel engine (1); The cylinder area (101) and the intercooler area (102) are both provided with corresponding water inlet pipes and water outlet pipes, and corresponding water inlet pumps are provided on the respective water inlet pipes; The water inlet pumps of the cylinder area (101) and the intercooler area (102) are respectively connected to a water replenishment unit (6) and an expansion water tank (5) for replenishing water; It also includes a radiator unit (4), which is connected to the water inlet pipe and the water outlet pipe of the cylinder area (101) and the intercooler area (102) at the same time, and cools the cylinder area (101) and the intercooler area (102) respectively; The pipes connecting the radiator unit (4) and the water inlet pipes of the cylinder area (101) and the intercooler area (102) are connected to the expansion water tank (5) to simultaneously realize the water replenishment and cooling functions; The water outlet pipes of the cylinder area (101) and the intercooler area (102) are both connected to a temperature control three-way valve, and the three channels of the temperature control three-way valve are respectively connected to the water outlet pipe, the water inlet pipe and the radiator unit (4) of the cylinder area (101) and the intercooler area (102); A water outlet pipe located on the cylinder area (101) is connected in a section before the temperature control three-way valve with a first check valve (19) and a preheating unit (3) for preheating the diesel engine (1) arranged in parallel; The water inlet pump located on the intercooler area (102) is also provided with a bypass pipeline, and the bypass pipeline is connected to the pipelines of the lubricating oil cooler (11) and the fuel return cooler (12) which are arranged in parallel; The water replenishment unit (6) comprises a water replenishment tank (601) and a water replenishment pump (609) for replenishing water into the diesel engine (1).

2. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 1, characterized in that: The cylinder area (101) is provided with a plurality of groups of cylinder assemblies connected in parallel, and is provided with high-temperature water inlet pipes and high-temperature water outlet pipes corresponding to the plurality of groups of cylinder assemblies, a high-temperature water inlet pump (7) is provided on the high-temperature water inlet pipe, and the high-temperature water inlet pump (7) is respectively connected to a water replenishment unit (6) and an expansion water tank (5) for replenishing water; A first stop valve (17) is provided at the connection between the water replenishment unit (6) and the high-temperature water inlet pipe to control the flow rate, and a first butterfly valve (21) is provided at the connection between the expansion water tank (5) and the high-temperature water inlet pipe to control the flow rate.

3. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 2, characterized in that: The intercooler area (102) is provided with a plurality of parallel intercooler assemblies, and is provided with low-temperature water inlet pipes and low-temperature water outlet pipes corresponding to the plurality of cylinder assemblies, the low-temperature water inlet pipe is provided with a low-temperature water inlet pump (8), and the low-temperature water inlet pump (8) is respectively connected to a water replenishment unit (6) and an expansion water tank (5) for replenishing water; A second stop valve (18) is provided at the connection between the water replenishment unit (6) and the low-temperature water inlet pipe to control the flow rate, and a second butterfly valve (23) is provided at the connection between the expansion water tank (5) and the low-temperature water inlet pipe to control the flow rate.

4. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 3, characterized in that: The radiator unit (4) comprises two radiator assemblies which are connected in parallel and are used to dissipate heat from the cylinder area (101) and the intercooler area (102) respectively.

5. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 4, characterized in that: The radiator unit (4) is connected to the water inlet end of the high-temperature water inlet pipe and the water outlet end of the high-temperature water outlet pipe to form a high-temperature water circulation channel; the radiator unit (4) is connected to the water inlet end of the low-temperature water inlet pipe and the water outlet end of the low-temperature water outlet pipe to form a low-temperature water circulation channel.

6. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 1, characterized in that: The water replenishment unit (6) is arranged below the diesel engine (1); a first ball valve (603) is provided on the water inlet pipe of the water replenishment tank (601); a filter (610) and a fourth ball valve (611) are connected between the water replenishment pump (609) and the water replenishment tank (601); The water outlet pipe of the water supply pump (609) is connected to the diesel engine (1) and the water supply tank (601) respectively, and a second check valve (608) is arranged on the main pipe of the water outlet pipe of the water supply pump (609). Meanwhile, a second ball valve (606) is arranged on the connecting pipe between the water outlet pipe of the water supply pump (609) and the water supply tank (601), and a third ball valve (607) is arranged on the connecting pipe between the water outlet pipe of the water supply pump (609) and the diesel engine (1), so as to control the opening and closing and flow rate of each pipe respectively. The water replenishment tank (601) is also provided with a water replenishment tank medicine adding port (604), a water replenishment tank venting port (605), a liquid level meter (602) for detecting the liquid level, and a liquid discharge pipe, and the liquid discharge pipe is provided with a third stop valve (612).

7. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 6, characterized in that: The top of the expansion water tank (5) is also provided with an expansion water tank exhaust port (24) for ensuring the internal pressure of the expansion water tank. The expansion water tank (5) is equipped with an expansion water tank level gauge (26) for detecting the water level. The expansion water tank (5) is also provided with an expansion water tank water replenishment port (25) for temporary water replenishment. The expansion water tank water replenishment port (25) is connected to the water replenishment tank (601).

8. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 2, characterized in that: The high-temperature water outlet pipe is provided with a high-temperature water exhaust valve (9) at the highest position, the low-temperature water outlet pipe is provided with a low-temperature water exhaust valve (10) at the highest position, and a throttling orifice plate is provided on the connecting pipes between the temperature control three-way valves on the cylinder area (101) and the intercooler area (102) and the water inlet pipes of the cylinder area (101) and the intercooler area (102).

9. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 1, characterized in that: The preheating unit (3) comprises a pre-supply water pump (301) and a standby pre-supply water pump (302) connected in parallel, and an electric heater (306) and a lubricating oil heat exchanger (305) connected to the pre-supply water pump (301) and the standby pre-supply water pump (302), and a third check valve (303) and a fourth check valve (304) are respectively provided on the pre-supply water pump (301) and the standby pre-supply water pump (302).

10. A cooling water system for emergency diesel generator sets for nuclear power plants as claimed in claim 1, characterized in that: A first throttling orifice plate (13) is provided on a pipeline connecting the water inlet pump of the intercooler area (102) and the lubricating oil cooler (11) and the fuel return oil cooler (12) arranged in parallel, and a second throttling orifice plate (14) is provided on the pipeline of the fuel return oil cooler (12). The parallel pipelines of the lubricating oil cooler (11) and the fuel return oil cooler (12) are also connected to a water outlet pipe before the temperature control three-way valve located in the intercooler area (102).

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