Bulb tubular unit lubricating oil system and control method

Abstract

The invention discloses a bulb tubular unit lubricating oil system and a control method, and belongs to the technical field of bulb tubular unit lubrication. The system comprises a low-level oil tank, a high-level oil tank, an oil cooler and an oil supply switching valve, and switching of two operation states is achieved through the height difference and an oil pump. During self-flowing operation, oil in the high-level oil tank is supplied to the unit, and oil in the low-level oil tank is pumped into the high-level oil During forced circulation operation, oil in the low-level oil tank is directly supplied to the unit through the oil pump and the oil cooler. The control method comprises the steps of starting the lubricating oil system, opening the oil supply valve, starting the oil pump, checking the oil pump and flow, switching the operation state and the like. According to the method, the lubricating oil can quickly reach the starting condition, the safety of a unit at low oil temperature is guaranteed, manual oil quantity adjustment is avoided, the problem of insufficient oil quantity caused by inaccurate calculation of pipeline loss is solved, the reliability of a unit lubricating oil system is improved, and the method has good popularization and application prospects in similar units.

Description

Technical Field

[0001] The present invention relates to the technical field of lubrication for bulb tubular units, and particularly to a lubricating oil system and control method for bulb tubular units. Background Art

[0002] The main shaft of a bulb tubular unit is generally horizontally arranged. Due to the limitation of the overall structure of the unit, the bearings of the unit adopt an external forced circulation cooling lubrication method. The bearings of the bulb tubular unit include positive and reverse thrust bearings, generator guide bearings and turbine guide bearings. Generally, the same set of lubricating oil system is used to supply oil to each bearing of the unit. At present, the existing bearing oil supply systems of domestic bulb tubular hydropower stations usually adopt a method of leading out a main oil supply pipe from a high-level oil tank and then supplying oil to each bearing of the unit by self-flow through each branch pipe. The high-level oil tank is filled with oil by a lubricating oil pump installed at the low-level oil tank, and an overflow pipe is installed to return the excess oil volume to the low-level oil tank.

[0003] For the self-flow oil supply method that generates oil pressure by the position height difference between the high-level oil tank and the bearing, its flow rate is greatly affected by the pipeline resistance loss. It may not be able to meet the oil consumption conditions of the unit due to improper selection of the elevation of the oil tank layout, pipelines, valves, etc., resulting in an increase in resistance loss. At the same time, temperature has a great influence on the viscosity of the lubricating oil. Affected by seasonal changes or the decrease in oil temperature after the unit has been shut down for a long time, it is difficult for the lubricating oil flow rate of the unit to quickly reach the starting condition. Operations such as turning on the oil tank heater to heat the oil or adjusting the opening of the oil supply valve are required, which increases the workload of the operating personnel and reduces the power generation response time of the power station. Summary of the Invention

[0004] Aiming at the deficiencies existing in the prior art, the present invention studies a lubricating oil system and control method for bulb tubular units, which has the advantages of being safe and flexibly coping with environmental changes, etc. It solves the problems that the lubricating oil of bulb tubular units has insufficient flow rate due to temperature influence, limited gravity oil pressure, unstable manual lubricating oil flow rate adjustment, and low starting response speed, etc., and can reduce the unit starting time and improve the reliability of the unit lubricating oil system.

[0005] To solve the above technical problems, the present invention is realized through the following technical solutions:

[0006] On the one hand, the present invention provides a lubricating oil system for a bulb tubular unit, including a low-level oil tank, a high-level oil tank, an oil cooler, and a supply oil switching valve. The heights of the high-level oil tank, the bulb tubular unit, and the low-level oil tank decrease in sequence. The high-level oil tank is connected to the first interface of the supply oil switching valve through a first supply oil pipeline. The second interface of the supply oil switching valve is connected to the bulb tubular unit through a second supply oil pipeline. The high-level oil tank is connected to the third interface of the supply oil switching valve through a third supply oil pipeline. A oil pump and an outlet valve group are installed on the low-level oil tank. The oil pump and the outlet valve group are connected to the oil cooler through a fourth supply oil pipeline. The oil cooler is connected to the fourth interface of the supply oil switching valve through the fourth supply oil pipeline. The supply oil switching valve is used to switch between the following two operating states:

[0007] In the gravity flow operating state, the lubricating oil in the high-level oil tank flows to the bulb tubular unit through the first supply oil pipeline, the first interface, the second interface, and the second supply oil pipeline. The lubricating oil in the low-level oil tank flows to the high-level oil tank through the oil pump and the outlet valve group, the oil cooler, the fourth supply oil pipeline, the fourth interface, the third interface, and the third supply oil pipeline.

[0008] In the forced circulation operating state, the lubricating oil in the low-level oil tank flows to the bulb tubular unit through the oil pump and the outlet valve group, the oil cooler, the fourth supply oil pipeline, the fourth interface, the second interface, and the second supply oil pipeline, and the first interface and the third interface are disconnected.

[0009] As a further optimized solution of the present invention, the low-level oil tank is installed in the lowest water turbine well, the high-level oil tank is arranged in the upper part of the powerhouse, and the supply oil switch is installed near the bulb tubular unit.

[0010] As a further optimized solution of the present invention, the supply oil switching valve is a two-position four-way valve and adopts a hydraulic control operation mode.

[0011] As a further optimized solution of the present invention, the high-level oil tank is connected to the low-level oil tank through an overflow pipe.

[0012] As a further optimized solution of the present invention, the oil cooler is installed at the low-level oil tank or between the high-level oil tank and the low-level oil tank.

[0013] As a further optimized solution of the present invention, a bearing high-pressure oil jacking system is installed on the low-level oil tank, and the bearing high-pressure oil jacking system is connected to the bulb tubular unit through a fifth supply oil pipeline.

[0014] As a further optimized solution of the present invention, the bulb tubular unit is connected to the low-level oil tank through a sixth supply oil pipeline.

[0015] As a further optimized solution of the present invention, a temperature transmitter, an oil-water mixture signaler and a liquid level switch are installed on the low-level oil tank; an oil-water mixture signaler and a liquid level switch are installed on the high-level oil tank; a pressure switch is installed on the oil pump and the outlet valve group to judge the operation state of the oil pump; a flow meter is installed on the fourth oil supply pipeline at the outlet of the oil cooler, and a flow meter is installed on the second oil supply pipeline between the oil supply switching valve and the bulb tubular unit.

[0016] On the other hand, the present invention provides a control method for the lubricating oil system of a bulb tubular unit, including the following steps:

[0017] S1. When the unit startup process enters, start the lubricating oil system;

[0018] S2. Send a command to open the oil supply valve of the lubricating oil system;

[0019] S3. Send a command to start the oil pump;

[0020] S4. Check the operation state of the oil pump:

[0021] If the main pump runs successfully, continue to the next step;

[0022] If the startup of the main pump fails, trigger an alarm and then start the standby oil pump;

[0023] If the startup of the standby pump fails, the whole process exits, and fault alarm and handling are carried out;

[0024] If the standby pump runs successfully, continue to the next step;

[0025] S5. Judge the operation state of the oil supply switching valve:

[0026] If the oil supply switching valve is in the forced circulation state, continue to the next step;

[0027] Otherwise, operate the oil supply switching valve, set it to the forced circulation state and then continue to the next step;

[0028] S6. Flow check:

[0029] After the oil pump runs, the system monitors the flow within 30 seconds;

[0030] If the flow reaches the specified value within 30 seconds, it is judged that the oil supply is successful;

[0031] If the flow is abnormal, the process exits and corresponding fault handling is carried out;

[0032] S7. Monitor the oil temperature:

[0033] After the oil supply is successful, monitor the system operation. If the oil temperature reaches the specified value, operate the oil supply switching valve and set it to the gravity flow operation state.

[0034] As a further optimized solution of the present invention, when there is a small elevation difference between the high-level oil tank and the bulb tubular unit and the oil temperature is low, resulting in a high viscosity of the lubricating oil, it operates in a forced circulation mode, and the low-level oil tank supplies oil to the bulb tubular unit; in the case of a pump accident, the oil supply switching valve automatically switches to the gravity flow operation mode, and the high-level oil tank supplies oil to the bulb tubular unit.

[0035] Through unique system design and control methods, the present invention effectively solves various problems existing in the lubricating oil system of the bulb tubular unit, and significantly improves the operation performance and reliability of the unit.

[0036] Achieve rapid attainment of the oil flow in the lubricating oil system to the starting condition: In the forced circulation operation state, the lubricating oil in the low-level oil tank flows directly to the bulb tubular unit after passing through the oil pump and the outlet valve group and the oil cooler. The oil pump provides power to make the lubricating oil flow rapidly, without being affected by the elevation difference between the high-level oil tank and the bearing and the pipeline resistance loss. When the oil temperature is low, such as in winter, and the viscosity of the lubricating oil increases, it is difficult to meet the oil consumption conditions of the unit in the gravity flow operation mode. The forced circulation mode can ensure that the lubricating oil quickly reaches the required flow rate for starting, shorten the starting time, and improve the response speed of the power station output.

[0037] Ensure the safe operation of the unit during long-term shutdown and in low oil temperature conditions such as winter: On the one hand, a high-level oil tank is set as the lubricating oil source for emergency shutdown. In the case of accidents such as pump failure and power loss, the oil supply switching valve automatically and quickly switches to the gravity flow oil supply mode of the high-level oil tank by relying on the spring pressure. The stored oil in the high-level oil tank can maintain the operation of the unit until shutdown, avoiding the burning of the bearings of each part of the unit due to lack of oil during the shutdown process. On the other hand, in the case of low oil temperature, the forced circulation operation state can be adopted, and the oil pump operates continuously to ensure the normal supply and circulation of the lubricating oil, and ensure the safe and stable operation of the unit under harsh working conditions.

[0038] Avoid manual adjustment of the lubricating oil volume during operation: The present invention realizes the automatic switching between the gravity flow operation state and the forced circulation operation state through the oil supply switching valve. The system can automatically adjust the operation mode according to parameters such as oil temperature and flow rate, without the need for manual operation to frequently turn on the oil tank heater to heat the oil or adjust the opening of the oil supply valve. When the oil temperature reaches the specified value, the oil supply switching valve is automatically set to the gravity flow operation state; when the oil temperature is low or the flow rate is abnormal, it switches to the forced circulation state, realizing intelligent control, reducing the workload of the operating personnel, and reducing the risk of human operation errors.

[0039] To solve the problem of insufficient lubricating oil in the unit lubricating oil system that may be caused by the difficulty in accurately calculating the pipeline loss during the design stage and improve the reliability of the unit lubricating oil system: When the pipeline loss cannot be accurately calculated, the gravity oil supply method may not meet the oil consumption conditions of the unit due to increased resistance loss. The forced circulation operating state of the present invention is not restricted by this. Regardless of the pipeline loss, the oil pump can ensure the stable supply of lubricating oil. A plurality of monitoring components are provided in the system, such as temperature transmitters, oil-water mixture signalers, liquid level switches, pressure switches, and flow meters, to monitor the operating state of the system in real time. Once an abnormality occurs, alarms and processing can be carried out in a timely manner to further improve the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the schematic diagram of the lubricating oil system of the bulb tubular unit of the present invention.

[0041] Figure 2 is the schematic diagram of the oil supply switching valve of the present invention.

[0042] Figure 3 is the electrical control block diagram of the lubricating oil system of the bulb tubular unit of the present invention.

[0043] Figure 4 is the flow chart of the control method for the lubricating oil system of the bulb tubular unit of the present invention.

[0044] Reference numerals in the figures: 1 - low-level oil tank, 2 - high-level oil tank, 3 - oil cooler, 4 - oil supply switching valve, 41 - first interface, 42 - second interface, 43 - third interface, 44 - fourth interface, 45 - limit switch, 46 - electromagnetic reversing valve, 47 - return spring, 5 - bulb tubular unit, 6 - oil pump and outlet valve group, 7 - bearing high-pressure oil jacking system, 8 - first oil supply pipeline, 9 - second oil supply pipeline, 10 - third oil supply pipeline, 11 - fourth oil supply pipeline, 12 - fifth oil supply pipeline, 13 - sixth oil supply pipeline, 14 - overflow pipe, 15 - temperature transmitter, 16 - oil-water mixture signaler, 17 - liquid level switch, 18 - pressure switch, 19 - flow meter. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the preferred implementation schemes of the present invention will be described below in conjunction with specific embodiments. However, it should be understood that the drawings are only for illustrative purposes and cannot be construed as a limitation of this patent; in order to better illustrate this embodiment, some components in the drawings will be omitted, enlarged or reduced, which do not represent the actual size of the product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as a limitation of this patent.

[0046] AsFigure 1 As shown in the figure, an embodiment of the present invention provides a lubricating oil system for a bulb tubular unit, which includes a low-level oil tank 1, a high-level oil tank 2, an oil cooler 3 and an oil supply switching valve 4. The heights of the high-level oil tank 2, the bulb tubular unit 5 and the low-level oil tank 1 decrease in sequence; the high-level oil tank 2 is connected to the first interface 41 of the oil supply switching valve 4 through a first oil supply pipeline 8, the second interface 42 of the oil supply switching valve 4 is connected to the bulb tubular unit 5 through a second oil supply pipeline 9, and the high-level oil tank 2 is connected to the third interface 43 of the oil supply switching valve 4 through a third oil supply pipeline 10; a oil pump and an outlet valve group 6 are installed on the low-level oil tank 1, the oil pump and the outlet valve group 6 are connected to the oil cooler 3 through a fourth oil supply pipeline 11, and the oil cooler 3 is connected to the fourth interface 44 of the oil supply switching valve 4 through the fourth oil supply pipeline 11.

[0047] The oil supply switching valve 4 is used to switch between the following two operating states:

[0048] In the gravity flow operating state, the lubricating oil in the high-level oil tank 2 flows to the bulb tubular unit 5 through the first oil supply pipeline 8, the first interface 41, the second interface 42 and the second oil supply pipeline 9, and the lubricating oil in the low-level oil tank 1 flows to the high-level oil tank 2 through the oil pump and the outlet valve group 6, the oil cooler 3, the fourth oil supply pipeline 11, the fourth interface 44, the third interface 43 and the third oil supply pipeline 10;

[0049] In the above solution, the low-level oil tank 1, the high-level oil tank 2, the oil cooler 3 and the oil supply switching valve 4 constitute the core architecture of the lubricating oil system. Each component is connected through specific pipelines. The first oil supply pipeline 8, the second oil supply pipeline 9, the third oil supply pipeline 10 and the fourth oil supply pipeline 11 ensure the orderly flow of lubricating oil in the system. During the connection process, it is necessary to ensure good pipeline sealing to prevent lubricating oil leakage, and the pipe diameter selection needs to be determined through calculation according to the lubricating oil flow rate and pressure requirements to ensure smooth oil flow. A complete lubricating oil circulation path is constructed. In the gravity flow operating state, the lubricating oil supply is realized by the gravity of the high-level oil tank, and in the forced circulation operating state, the oil supply is carried out by the power of the oil pump. The two operating states cooperate with each other to ensure the lubrication requirements of the unit under different working conditions and improve the operating flexibility of the system.

[0050] In the forced circulation operating state, the lubricating oil in the low-level oil tank 1 flows to the bulb tubular unit 5 through the oil pump and the outlet valve group 6, the oil cooler 3, the fourth oil supply pipeline 11, the fourth interface 44, the second interface 42 and the second oil supply pipeline 9, and the first interface 41 and the third interface 43 are disconnected.

[0051] In some embodiments, the low-position oil tank 1 is installed at the lowest position in the turbine well, and the lubricating oil returned by the system is conveniently collected by gravity. During installation, it is necessary to ensure that the foundation of the oil tank is stable and can bear the weight after being filled with lubricating oil. At the same time, waterproof and moisture-proof measures should be taken to avoid corrosion of the oil tank. The high-position oil tank 2 is arranged at the upper part of the power house, and the specific elevation is determined according to the system height difference requirement. When installing, it is necessary to consider convenient maintenance, and enough space should be reserved around it. The oil supply switching valve 4 is installed close to the bulb tubular unit 5 to reduce the pipeline length and the oil flow resistance. When connecting the pipelines, the layout direction should be reasonably planned to avoid interference with other equipment.

[0052] As Figure 2 shown, in some embodiments, the oil supply switching valve 4 is a two-position four-way valve and adopts a hydraulic control operation mode. The oil pressure in the control chamber of the oil supply switching valve 4 comes from the electromagnetic reversing valve 46, and its pressure depends on the electrical control signal of the electromagnetic reversing valve 46. A return spring 47 is provided on the other side of the valve core of the oil supply switching valve 4. In the case of no oil pressure in the control chamber, the valve core will automatically return to the initial position. The oil supply switching valve 4 adopts a hydraulic control operation mode and is equipped with a hydraulic accumulator. The hydraulic accumulator cooperates with the oil supply switching valve 4 to quickly switch the valve position and avoid interruption of the oil flow. A limit switch 45 is provided on the oil supply switching valve 4 to determine the working mode of the oil supply switching valve 4. The oil supply switching valve 4 can directly connect the lubricating oil pipe from the oil pump through the oil cooler 3 to the oil supply pipe of the unit bearing, or connect the lubricating oil pipe from the oil pump through the oil cooler 3 to the high-position oil tank 2, and at the same time connect the outlet pipe of the high-position oil tank 2 to the oil supply pipe of the unit bearing.

[0053] In some embodiments, the high-position oil tank 2 is connected to the low-position oil tank 1 through an overflow pipe 14. The diameter of the overflow pipe 14 is designed according to the maximum overflow volume of the high-position oil tank 2 to ensure that when the oil level in the high-position oil tank 2 is too high, the lubricating oil can flow smoothly to the low-position oil tank 1. A valve can be installed on the overflow pipe 14 to facilitate closing in special situations such as maintenance to prevent leakage of the lubricating oil. The installation of the overflow pipe 14 should ensure a certain slope to facilitate the self-flow of the lubricating oil.

[0054] In some embodiments, the oil cooler 3 is installed at the low-position oil tank 1 or between the high-position oil tank 2 and the low-position oil tank 1. When the oil cooler 3 is installed at the low-position oil tank 1, it is convenient to directly cool the lubricating oil pumped out from the low-position oil tank 1. The connecting oil pipeline is short and the heat exchange efficiency is high. When installed between the high-position oil tank 2 and the low-position oil tank 1, it is beneficial to the layout of the cooling medium pipeline of the oil cooler and convenient for operation and maintenance. During the installation process, it is necessary to ensure that the inlet and outlet connections of the cooling medium (such as water or air) are correct and the flow rate of the cooling medium is stable.

[0055] In some embodiments, a bearing high-pressure oil jacking system 7 is installed on the low-position oil tank 1. The bearing high-pressure oil jacking system 7 is connected to the bulb tubular unit 5 through a fifth oil supply pipeline 12. During the startup and shutdown processes of the unit, it can establish an oil film between the journal and the bearing bush of the unit to ensure... Prevent dry friction and ensure the safety of the bearings during the low-speed startup and shutdown processes of the unit.

[0056] In some embodiments, the bulb tubular unit 5 is connected to the low-position oil tank 1 through a sixth oil supply pipeline 13. The connection point of the sixth oil supply pipeline 13 is located at a suitable position of the unit, facilitating the collection of the lubricating oil cooled for each bearing of the unit.

[0057] In some embodiments, a temperature transmitter 15, an oil-water mixture signal device 16, and a liquid level switch 17 are installed on the low-position oil tank 1; an oil-water mixture signal device 16 and a liquid level switch 17 are installed on the high-position oil tank 2; a pressure switch 18 is installed on the oil pump and outlet valve group 6 to judge the operating state of the oil pump; a flowmeter 19 is installed on the fourth oil supply pipeline 11 at the outlet of the oil cooler 3, and a flowmeter 19 is installed on the second oil supply pipeline 9 between the oil supply switching valve 4 and the bulb tubular unit 5. As Figure 3 shown, each automation component is connected to the control unit of the electrical control system. The control unit receives and processes the information collected by the automation components, calculates the control signal according to the control flow algorithm, and then outputs it to actuators such as indicator lights, meters, oil supply valves, soft starters of oil pumps, and switching valves. The bearing high-pressure oil jacking system 7 is put into use during the startup of the unit and is withdrawn after the unit reaches the rated speed. During the shutdown process, after the unit speed drops to the specified value, the bearing high-pressure oil jacking system 7 is automatically put into use and is withdrawn after the shutdown is completed.

[0058] The lubricating oil system of the bulb tubular unit has two operating modes. One is that the lubricating oil operates in a gravity flow mode, that is, it is supplied to the bearings of the unit for lubrication from the high-position oil tank 2 by gravity flow, and then is collected through the sixth oil supply pipeline 13 and discharged to the low-position oil tank 1. Finally, the oil pump pumps the lubricating oil from the low-position oil tank 1 through the oil cooler 3 and into the high-position oil tank 2. The other is that the lubricating oil operates in a forced circulation mode, that is, the high-position oil tank 2 is removed from the lubricating oil system during operation. The oil pump pressurizes the lubricating oil from the low-position oil tank 1, supplies it directly to the bearings of the unit for lubrication through the oil cooler 3, and then is collected through the sixth oil supply pipeline 13 and discharged back to the low-position oil tank 1. This operating mode can achieve fast and stable oil flow, and the flow rate reaches the startup condition.

[0059] The main logic of this method is that upon receiving the startup instruction, the oil supply switching valve is controlled to be in the forced circulation mode: the bearing oil pump is started, the oil supply valve of the oil tank is opened, and the lubricating oil circulation begins. When there is no abnormality during the unit startup process and it enters the idling state, the system switches to the gravity flow mode of operation: the oil supply switching valve is controlled to act, and the oil flow passes through the oil cooler and then enters the high-level oil tank 2. The lubricating oil in the high-level oil tank 2 flows by gravity into the bearings of each part of the unit. At this time, the oil pump runs intermittently according to the oil level range of the high-level oil tank 2. When the oil level exceeds the oil overflow port, the lubricating oil flows into the low-level oil tank 1 through the overflow pipe 14.

[0060] In power stations where the elevation difference between the high-level oil tank 2 and the bearings is small, or in winter when the oil temperature is low and the viscosity of the lubricating oil increases, and the gravity flow mode of operation of the lubricating oil system cannot meet the flow conditions for the safe operation of the unit, the forced lubricating oil system circulation mode can be adopted. The oil pump runs continuously, and the high-level oil tank 2 serves as the lubricating oil source for emergency shutdown. In case of accidents such as oil pump failure or power failure, the oil supply switching valve 4 automatically and quickly switches to the gravity flow oil supply mode from the high-level oil tank 2 by relying on the spring pressure. The stored oil in the high-level oil tank 2 can maintain the operation of the unit until shutdown, ensuring that the bearings of each part of the unit do not burn out during the shutdown process.

[0061] After receiving the shutdown instruction, close the oil supply valve and stop the oil pump.

[0062] As Figure 4 shown, the embodiment of the present invention provides a control method for the lubricating oil system of a bulb tubular turbine unit, including the following steps:

[0063] (1) When the unit startup process enters the startup lubricating oil system;

[0064] (2) Issue a command to open the oil supply valve of the lubricating oil system;

[0065] (3) Issue a command to start the oil pump;

[0066] (4) Check the operating state of the oil pump:

[0067] If the main pump runs successfully, continue to the next step;

[0068] If the startup of the main pump fails, trigger an alarm, and then start the standby oil pump;

[0069] If the startup of the standby pump fails, the entire process exits, and a fault alarm and handling are carried out;

[0070] If the standby pump runs successfully, continue to the next step;

[0071] (5) Judge the operating state of the oil supply switching valve:

[0072] If the oil supply switching valve is in the forced circulation state, continue to the next step;

[0073] Otherwise, actuate the oil supply switching valve, set it to the forced circulation state and continue to the next step;

[0074] (6) Flow rate check:

[0075] After the oil pump runs, the system monitors the flow rate within 30 seconds;

[0076] If the flow rate reaches the specified value within 30 seconds, it is judged that the oil supply is successful;

[0077] If the flow rate is abnormal, the process exits and corresponding fault handling is performed;

[0078] (7) Monitor the oil temperature:

[0079] After the oil supply is successful, monitor the system operation. If the oil temperature reaches the specified value, actuate the oil supply switching valve and set it to the gravity flow operation state.

[0080] Based on a lubricating oil system and control method for a bulb tubular unit provided by an embodiment of the present invention, through a series of logical controls and status monitors, the stable operation of the unit lubricating oil system can be ensured, and the startup time of the bulb tubular unit is reduced. It can solve the problem of insufficient system lubricating oil volume that may be caused by the difficulty in accurately calculating the pipeline loss of the unit lubricating oil system during the design stage, and improve the reliability and safety of the lubricating oil system of the bulb tubular unit.

[0081] It should be noted that the time and flow rate specified values in the control method are given by professionals according to the actual situation, and this embodiment does not make any limitations. Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meaning understood by those of ordinary skill in the field to which the present invention belongs. Words such as "including" or "comprising" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but can be electrical connections, whether direct or indirect.

[0082] The present invention aims to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Any omission, modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention still fall within the scope of the invention's patent.

Claims

1. A lubricating oil system for a bulb tubular unit, characterized in that: It includes a low-level oil tank (1), a high-level oil tank (2), an oil cooler (3) and an oil supply switching valve (4). The heights of the high-level oil tank (2), the bulb tubular unit (5) and the low-level oil tank (1) decrease in sequence. The high-level oil tank (2) is connected to the first interface (41) of the oil supply switching valve (4) through a first oil supply pipeline (8). The second interface (42) of the oil supply switching valve (4) is connected to the bulb tubular unit (5) through a second oil supply pipeline (9). The high-level oil tank (2) is connected to the third interface (43) of the oil supply switching valve (4) through a third oil supply pipeline (10). A pump and outlet valve group (6) is installed on the low-level oil tank (1). The pump and outlet valve group (6) is connected to the oil cooler (3) through a fourth oil supply pipeline (11). The oil cooler (3) is connected to the fourth interface (44) of the oil supply switching valve (4) through the fourth oil supply pipeline (11). The oil supply switching valve (4) is used to switch between the following two operating states: In the gravity flow operating state, the lubricating oil in the high-level oil tank (2) flows to the bulb tubular unit (5) through the first oil supply pipeline (8), the first interface (41), the second interface (42) and the second oil supply pipeline (9). The lubricating oil in the low-level oil tank (1) flows to the high-level oil tank (2) through the pump and outlet valve group (6), the oil cooler (3), the fourth oil supply pipeline (11), the fourth interface (44), the third interface (43) and the third oil supply pipeline (10). In the forced circulation operating state, the lubricating oil in the low-level oil tank (1) flows to the bulb tubular unit (5) through the pump and outlet valve group (6), the oil cooler (3), the fourth oil supply pipeline (11), the fourth interface (44), the second interface (42) and the second oil supply pipeline (9). The first interface (41) and the third interface (43) are disconnected.

2. The lubricating oil system of the bulb tubular unit according to claim 1, characterized in that: The low-level oil tank (1) is installed in the lowest-positioned turbine well. The high-level oil tank (2) is arranged in the upper part of the powerhouse. The oil supply switch is installed near the bulb tubular unit (5).

3. The lubricating oil system of the bulb tubular unit according to claim 1, wherein: The oil supply switching valve (4) is a two-position four-way valve and adopts a hydraulic control operation mode.

4. The lubricating oil system of the bulb tubular unit according to claim 1, characterized in that: The high-level oil tank (2) is connected to the low-level oil tank (1) through an overflow pipe (14).

5. The lubricating oil system of the bulb tubular unit according to claim 1, characterized in that: The oil cooler (3) is installed at the low-level oil tank (1) or between the high-level oil tank (2) and the low-level oil tank (1).

6. The lubricating oil system of the bulb tubular unit according to claim 1, wherein: A bearing high-pressure oil jacking system (7) is installed on the low-level oil tank (1). The bearing high-pressure oil jacking system (7) is connected to the bulb tubular unit (5) through a fifth oil supply pipeline (12).

7. The lubricating oil system of the bulb tubular unit according to claim 1, characterized in that: The bulb tubular unit (5) is connected to the low-level oil tank (1) through a sixth oil supply pipeline (13).

8. The lubricating oil system of the bulb tubular unit according to claim 1, wherein: A temperature transmitter (15), an oil-water mixture signaler (16) and a liquid level switch (17) are installed on the low-level oil tank (1); an oil-water mixture signaler (16) and a liquid level switch (17) are installed on the high-level oil tank (2); a pressure switch (18) is installed on the oil pump and outlet valve group (6) to judge the operation state of the oil pump; a flowmeter (19) is installed on the fourth oil supply pipeline (11) at the outlet of the oil cooler (3), and a flowmeter (19) is installed on the second oil supply pipeline (9) between the oil supply switching valve (4) and the bulb tubular turbine unit (5).

9. A control method for the lubricating oil system of a bulb tubular unit, characterized in that, It includes the following steps: S1. The unit startup process enters the starting lubricating oil system; S2. Issue a command to open the oil supply valve of the lubricating oil system; S3. Issue a command to start the oil pump; S4. Check the operation state of the oil pump: If the main pump runs successfully, proceed to the next step; If the startup of the main pump fails, trigger an alarm and then start the standby oil pump; If the startup of the standby pump fails, the entire process exits, and fault alarm and handling are performed; If the standby pump runs successfully, proceed to the next step; S5. Judge the operation state of the oil supply switching valve: If the oil supply switching valve is in the forced circulation state, proceed to the next step; Otherwise, operate the oil supply switching valve, set it to the forced circulation state and then proceed to the next step; S6. Flow check: After the oil pump runs, the system monitors the flow within 30 seconds; If the flow reaches the specified value within 30 seconds, it is judged that the oil supply is successful; If the flow is abnormal, the process exits and corresponding fault handling is performed; S7. Monitor the oil temperature: After the oil supply is successful, monitor the system operation. If the oil temperature reaches the specified value, operate the oil supply switching valve and set it to the gravity flow operation state.

10. The control method of the lubricating oil system of the bulb tubular turbine unit according to claim 9, characterized in that: In the case where the layout height difference between the high-level oil tank and the bulb tubular turbine unit is small and the oil temperature is low, resulting in a large viscosity of the lubricating oil, it operates in the forced circulation mode, and the low-level oil tank supplies oil to the bulb tubular turbine unit; In the case of an oil pump accident, the oil supply switching valve automatically switches to the gravity flow operation mode, and the high-level oil tank supplies oil to the bulb tubular turbine unit.

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