A kind of high-efficiency high-speed gear box evacuation system for combustion engine

Abstract

The application discloses a kind of high-efficiency high-speed gear box for gas turbine evacuation system, it is related to high-speed gear box technical field.The gear box, sealing assembly, auxiliary oil tank, vacuum pumping mechanism, pressure balance mechanism, lubricating mechanism and control system are included.There are mutually meshing gears in the gear box, and the sealing assembly sleeve forms a closed cavity in the gear box;Auxiliary oil tank returns lubricating oil to gas turbine unit oil station;Vacuum pumping mechanism suction end is connected with gear box, so that the closed cavity maintains negative pressure, exhaust end is connected with auxiliary oil tank;Pressure balance mechanism is connected with closed cavity, and can be selectively connected with external atmosphere;Lubricating mechanism supplies oil to gear meshing area and lubrication site of sealing assembly, and cooperates with negative pressure to guide oil from gear box into auxiliary oil tank;Control system is electrically connected with vacuum pumping, pressure balance and lubricating mechanism, and hard interlock control is carried out on vacuum pumping or lubricating mechanism, another mechanism is automatically stopped when one mechanism fails, application scenarios are expanded, and vacuum degree of vacuum cavity is stabilized.

Description

Technical Field

[0001] This invention relates to the field of high-speed gearbox technology, and in particular to a vacuum system for a high-efficiency high-speed gearbox for gas turbines. Background Technology

[0002] High-speed gearboxes, with their advantages of high speed, high power, and low noise, occupy a key position in large industrial equipment in industries such as petroleum, chemical, and metallurgical machinery. Their transmission efficiency directly affects the operating performance of the equipment and the economic benefits of enterprises. Statistics show that approximately 55% of the power loss in a gearbox originates from the meshing area, and 45% is generated by sliding bearings. Of the meshing losses, over 80% are attributed to aerodynamic effects (i.e., "wind resistance," or air resistance loss), while losses due to friction between gear pairs account for less than 20%. Therefore, reducing wind resistance loss is an effective way to improve gearbox efficiency. Reducing the amount of internal air is a common method, generally achieved by installing a vacuum system to reduce the air density inside the gearbox and decrease air resistance.

[0003] Limited applicability: Traditional vacuum systems can only pump air outwards and cannot discharge oil outwards. They are only suitable for gearboxes with internal oil storage and are not suitable for vacuum gearboxes with external oil supply, thus limiting their application scope.

[0004] Short lifespan of floating ring seals: In some structures, the floating ring seals are not lubricated and rub against the shaft dry, resulting in rapid wear and a short service life. Furthermore, as the service time increases, the leakage increases, causing the vacuum chamber pressure to rise and the gearbox efficiency to decrease. Summary of the Invention

[0005] The purpose of this invention is to provide a vacuum system for a high-efficiency, high-speed gearbox of a gas turbine, in order to solve the problems existing in the prior art, effectively expand the application scenarios, and effectively ensure the stability of the vacuum level in the vacuum chamber.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a vacuum system for a high-efficiency, high-speed gearbox of a gas turbine, comprising: a gearbox, a sealing assembly, an auxiliary oil tank, a vacuum mechanism, a pressure balancing mechanism, a lubrication mechanism, and a control system. The gearbox contains meshing gears, with the shafts of each gear passing through and extending out of the gearbox. The sealing assembly is sleeved around the outer circumference of each shaft extending out of the gearbox to seal the clearance between the shaft and the gearbox housing, forming a sealed cavity within the gearbox. The auxiliary oil tank is used to return received lubricating oil to the gas turbine's unit oil station. The suction end of the vacuum mechanism is connected to and communicates with the gearbox to maintain a set negative pressure state inside the sealed cavity. The exhaust end of the vacuum mechanism is connected to the auxiliary oil tank. The oil tank is connected and interconnected; the pressure balancing mechanism is connected to the sealed cavity, used to selectively connect the sealed cavity to the outside atmosphere; the lubrication mechanism is used to deliver lubricating oil to the gear meshing area and the lubrication part of the sealing assembly in the gearbox, and can cooperate with the negative pressure state of the sealed cavity to allow the lubricating oil to be introduced from the gearbox into the auxiliary oil tank; the control system is electrically connected to the vacuum mechanism, the pressure balancing mechanism and the lubrication mechanism, and can enable the vacuum mechanism or the lubrication mechanism to be under hard interlock control, so that if one of the vacuum mechanism or the lubrication mechanism fails, the other mechanism in the vacuum mechanism or the lubrication mechanism will be automatically stopped.

[0007] Preferably, the sealing assembly includes two sealing partitions and multiple floating ring seals. The two sealing partitions are symmetrically arranged inside the gearbox. Each sealing partition has a shaft hole through which the shaft of the gear passes. The floating ring seals are installed between the inner wall of the shaft hole and the outer wall of the shaft to enclose the space between the two sealing partitions inside the gearbox into the sealed cavity.

[0008] Preferably, the vacuuming mechanism includes a vacuum pump, an inlet pipe, and an exhaust pipe. One end of the inlet pipe is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the inlet of the vacuum pump. One end of the exhaust pipe is connected to and communicates with the exhaust port of the vacuum pump, and the other end is connected to and communicates with the auxiliary oil tank. The vacuum pump is connected to and communicates with the lubrication mechanism to obtain lubricating oil for lubrication and cooling.

[0009] Preferably, the pressure balancing mechanism includes a ventilation pipeline, a ventilation valve, an internal pressure sensor, and an internal pressure regulating valve. The internal pressure sensor is installed inside the sealed cavity to monitor the pressure value inside the sealed cavity and is electrically connected to the control system. One end of the ventilation pipeline is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank. The ventilation valve is installed on the ventilation pipeline and is electrically connected to the control system. The internal pressure regulating valve is installed on the ventilation pipeline and is connected in parallel with the ventilation valve. The vacuum pump can change the motor frequency according to the pressure value monitored by the internal pressure sensor to stably maintain the pressure inside the sealed cavity within a set negative pressure range.

[0010] Preferably, the lubrication mechanism includes a main oil inlet pipe, a first oil inlet branch pipe, a second oil inlet branch pipe, a lubrication control valve, a first oil return pipe, an oil pump, a first check valve, and a thermal expansion joint. One end of the main oil inlet pipe is connected to and communicates with the unit oil station of the gas turbine, and the other end is connected to and communicates with the first oil inlet branch pipe and the second oil inlet branch pipe. The end of the first oil inlet branch pipe away from the main oil inlet pipe extends to the gear meshing area in the gearbox. The end of the second oil inlet branch pipe away from the main oil inlet pipe extends to each of the floating ring seals. The lubrication control valve is disposed on the second oil inlet branch pipe and is electrically connected to the control system. One end of the first oil return pipe is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank. The oil pump, the first check valve, and the thermal expansion joint are sequentially disposed on the first oil return pipe along the flow direction of the lubricating oil, and the oil pump is electrically connected to the control system.

[0011] Preferably, the lubrication mechanism further includes a third oil inlet branch pipe, a second oil return pipe, a second check valve, and a third oil return pipe. One end of the third oil inlet branch pipe is connected to and communicates with the main oil inlet pipe, and the other end is connected to and communicates with the oil inlet of the vacuum pump. One end of the second oil return pipe is connected to and communicates with the oil return port of the vacuum pump, and the other end is connected to and communicates with the auxiliary oil tank. One end of the third oil return pipe is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank. The second check valve is disposed on the third oil return pipe.

[0012] Preferably, it also includes a bypass oil pipe, the oil inlet end of which is connected to the main oil inlet pipe, and the oil outlet end of which is connected to the oil inlet of the floating ring seal, for providing emergency lubrication to the floating ring seal when the lubrication control valve fails.

[0013] Preferably, the lubrication mechanism further includes a level gauge, an overflow valve, and an overflow pipe. The level gauge is installed inside the gearbox and can monitor the level of the lubricating oil in the sealed cavity. One end of the overflow pipe is connected to and communicates with the main oil inlet pipe, and the other end is connected to and communicates with the auxiliary oil tank. The overflow valve is disposed on the overflow pipe.

[0014] Preferably, the air exchange valve is a normally closed solenoid valve, and the lubrication control valve is a normally open solenoid valve.

[0015] The present invention achieves the following technical effects compared to the prior art: This invention provides a vacuum system for a high-efficiency, high-speed gearbox in a gas turbine. By incorporating a lubrication mechanism to deliver lubricating oil to the floating ring seal of the sealing assembly, it avoids dry friction between the floating ring seal and the shaft, effectively extending the service life of the floating ring seal while ensuring stable sealing performance. This prevents leakage from increasing too rapidly over time, reliably maintaining the vacuum level within the sealed cavity and stabilizing the gearbox's transmission efficiency. Furthermore, the lubrication mechanism can simultaneously maintain the vacuum state and promptly deliver the lubricating oil entering the sealed cavity to an auxiliary oil tank, adapting to externally supplied oil vacuum gearboxes. This effectively expands the applicability of the vacuum system and solves the problems of traditional vacuum systems being unable to discharge oil externally and having limited application scenarios. Simultaneously, the control system achieves hard interlock control between the vacuum mechanism and the lubrication mechanism, automatically switching operating modes in the event of a failure in either device, improving the safety and reliability of the system operation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the vacuum system for a high-efficiency, high-speed gearbox for a gas turbine provided by the present invention, taken from one angle. Figure 2 Another structural schematic diagram of the vacuum system for a high-efficiency, high-speed gearbox for a gas turbine provided by the present invention; Figure 3 A schematic diagram of the internal structure of the gearbox in the vacuum system for a high-efficiency, high-speed gearbox of a gas turbine provided by the present invention; Figure 4 A schematic diagram of the internal structure of the gearbox in the vacuum system for a high-efficiency, high-speed gearbox of a gas turbine provided by this invention; In the diagram: 1. Gearbox; 2. Auxiliary oil tank; 3. Sealing partition; 4. Floating ring seal; 5. Inlet pipe; 6. Vacuum pump; 7. Exhaust pipe; 8. Ventilation pipeline; 9. Ventilation valve; 10. Internal pressure sensor; 11. Internal pressure regulating valve; 12. Main oil inlet pipe; 13. First oil inlet branch pipe; 14. Second oil inlet branch pipe; 15. Lubrication control valve; 16. First oil return pipe; 17. Oil pump; 18. First check valve; 19. Thermal expansion joint; 20. Third oil inlet branch pipe; 21. Second oil return pipe; 22. Second check valve; 23. Third oil return pipe; 24. Bypass oil pipe; 25. Level gauge; 26. Overflow valve; 27. Overflow pipe; 28. Control system; 29. ​​Unit oil station. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The purpose of this invention is to provide a vacuum system for a high-efficiency, high-speed gearbox of a gas turbine, in order to solve the problems existing in the prior art, effectively expand the application scenarios, and effectively ensure the stability of the vacuum level in the vacuum chamber.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 This embodiment provides a vacuum system for a high-efficiency, high-speed gearbox 1 of a gas turbine, such as... Figures 1-4As shown, the system includes: a gearbox 1, a sealing assembly, an auxiliary oil tank 2, a vacuum mechanism, a pressure balancing mechanism, a lubrication mechanism, and a control system 28. The gearbox 1 contains meshing gears, with the shafts of each gear passing through and extending out of the gearbox 1. The sealing assembly is fitted around the outer circumference of each shaft extending out of the gearbox 1 to seal the clearance between the shaft and the gearbox 1 housing, forming a sealed cavity within the gearbox 1. The auxiliary oil tank 2 is used to return the received lubricating oil to the gas turbine's unit oil station 29. The suction end of the vacuum mechanism is connected to and communicates with the gearbox 1 to maintain a set negative pressure state inside the sealed cavity, and the exhaust end of the vacuum mechanism is connected to and communicates with the auxiliary oil tank 2. The pressure balancing mechanism communicates with the sealed cavity and is used to selectively ventilate the sealed cavity. The chamber is open to the outside atmosphere; the lubrication mechanism delivers lubricating oil to the gear meshing area and the lubrication points of the sealing components within the gearbox 1, and can also cooperate with the negative pressure state of the sealed chamber to allow lubricating oil to be introduced from the gearbox 1 into the auxiliary oil tank 2; the control system 28 is electrically connected to the vacuum mechanism, pressure balancing mechanism, and lubrication mechanism, and can enable the vacuum mechanism or lubrication mechanism to be under hard interlock control, so that if one of the vacuum mechanism or lubrication mechanism fails, the other mechanism will automatically stop. Through the coordinated setting of each mechanism, the functions of vacuuming, sealing, lubrication, and emergency fault handling of the gearbox 1 are realized, which can effectively improve the operating efficiency and safety of the gearbox 1. All parts work closely together to ensure that the gearbox 1 can operate stably under different operating conditions. The vacuum mechanism maintains negative pressure in the sealed cavity, reducing wind resistance loss and improving transmission efficiency; the sealing component ensures the sealing of the sealed cavity, preventing leakage from affecting the vacuum level and lubrication effect; the lubrication mechanism provides necessary lubrication for key parts, and at the same time, it works with negative pressure to achieve lubricating oil return; the hard interlock control of the control system 28 can protect the other mechanism in time when one mechanism fails, preventing the fault from escalating.

[0022] In a preferred embodiment, the sealing assembly includes two sealing partitions 3 and multiple floating ring seals 4. The two sealing partitions 3 are symmetrically arranged inside the gearbox 1. Each sealing partition 3 has a shaft hole through which the gear shaft passes. The floating ring seals 4 are installed between the inner wall of the shaft hole and the outer wall of the shaft, thus enclosing the space between the two sealing partitions 3 within the gearbox 1 to form a sealed cavity. The design of the sealing assembly effectively seals the gap between the shaft and the gearbox 1 housing, forming a sealed cavity and providing a basis for the vacuum mechanism to maintain a negative pressure environment. The use of floating ring seals 4 effectively reduces leakage and improves the sealing effect. Furthermore, their installation method is compatible with the shaft-passing structure, ensuring the reliability and stability of the overall seal. Compared to other sealing methods, floating ring seals 4 maintain good sealing performance even under high-speed rotating shaft conditions, reducing air entry into the sealed cavity and helping to maintain a stable vacuum level, thereby improving the operating efficiency of the gearbox 1. Compared to existing systems operating at normal pressure, this invention reduces the air density in the gear sealing cavity by evacuating the gear sealing cavity, resulting in a nearly 83% reduction in wind resistance and power consumption.

[0023] In a preferred embodiment, the vacuum pumping mechanism includes a vacuum pump 6, an inlet pipe 5, and an exhaust pipe 7. One end of the inlet pipe 5 is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the inlet of the vacuum pump 6. One end of the exhaust pipe 7 is connected to and communicates with the exhaust port of the vacuum pump 6, and the other end is connected to and communicates with the auxiliary oil tank 2. The vacuum pump 6 is connected to and communicates with the lubrication mechanism to obtain lubricating oil for lubrication and cooling. Through reasonable pipe connections, the vacuum pumping mechanism can effectively extract air from the sealed cavity, maintain the set negative pressure state, thereby reducing wind resistance loss in the gearbox 1 and improving transmission efficiency. The connection between the vacuum pump 6 and the lubrication mechanism to obtain lubricating oil not only achieves lubrication and cooling of the vacuum pump 6 itself, ensuring its stable operation, but also cleverly utilizes the lubrication resources within the system, simplifies the system structure, reduces additional oil supply equipment, and improves the integration and reliability of the entire system. For example, sufficient lubrication of the vacuum pump 6 can reduce wear on the rotor of the vacuum pump 6, ensuring the pumping effect; cooling of the vacuum pump 6 helps maintain its performance and extend its service life.

[0024] In a preferred embodiment, the pressure balancing mechanism includes a ventilation pipeline 8, a ventilation valve 9, an internal pressure sensor 10, and an internal pressure regulating valve 11. The internal pressure sensor 10 is installed in the sealed cavity to monitor the pressure value inside the sealed cavity and is electrically connected to the control system 28. One end of the ventilation pipeline 8 is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank 2. The ventilation valve 9 is installed on the ventilation pipeline 8 and is electrically connected to the control system 28. The internal pressure regulating valve 11 is installed on the ventilation pipeline 8 and is connected in parallel with the ventilation valve 9. The vacuum pump can change the motor frequency according to the pressure value monitored by the internal pressure sensor 10 to stably maintain the pressure inside the sealed cavity within the set negative pressure range. The pressure balancing mechanism can monitor and accurately control the pressure inside the sealed cavity in real time. The internal pressure sensor 10 provides accurate pressure data. The control system 28 adjusts the vacuum pump motor frequency based on this data, working in conjunction with the internal pressure regulating valve to dynamically adjust the pressure, ensuring the pressure within the sealed cavity remains within a stable set negative pressure range. When a system malfunction requires pressure relief, the ventilation valve can quickly open to connect the sealed cavity to the outside, achieving rapid pressure balancing and ensuring the safety of fault handling. Furthermore, after a period of operation, the unit may reach its maintenance cycle, or the vacuum pump may become unable to meet the required negative pressure range. In this case, the increased leakage rate of the sealed cavity due to gearbox operation can be reduced by adjusting the opening degree of the internal pressure regulating valve, allowing the vacuum pump to operate normally within the required negative pressure range.

[0025] In a preferred embodiment, the lubrication mechanism includes a main oil inlet pipe 12, a first oil inlet branch pipe 13, a second oil inlet branch pipe 14, a lubrication control valve 15, a first oil return pipe 16, an oil pump 17, and a first check valve 18. One end of the main oil inlet pipe 12 is connected to and communicates with the unit oil station 29 of the gas turbine, and the other end is connected to and communicates with the first oil inlet branch pipe 13 and the second oil inlet branch pipe 14. The end of the first oil inlet branch pipe 13 away from the main oil inlet pipe 12 extends to the gear meshing area inside the gearbox 1, and the end of the second oil inlet branch pipe 14 away from the main oil inlet pipe 12 extends to each floating ring seal 4. A sliding control valve 15 is installed on the second oil inlet branch pipe 14 and electrically connected to the control system 28. One end of the first return oil pipe 16 is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank 2. The oil pump 17, the first check valve 18, and the thermal expansion joint 19 are sequentially installed on the first return oil pipe 16 along the flow direction of the lubricating oil, and the oil pump 17 is electrically connected to the control system 28. Through reasonable pipeline layout and component arrangement, the lubrication mechanism can accurately deliver lubricating oil to the gear meshing area and the floating ring seal 4, ensuring the lubrication effect of key parts, reducing wear, and extending the service life of the equipment. The lubrication control valve 15 is electrically connected to the control system 28, which can realize precise control of the lubricating oil supply to the floating ring seal 4 and adjust the oil supply according to different working conditions. The installation of the oil pump 17 and the first check valve 18 ensures that the lubricating oil can be smoothly introduced from the gearbox 1 into the auxiliary oil tank 2 under the negative pressure of the sealed cavity, while preventing the lubricating oil backflow and ensuring the normal operation of the system.

[0026] In a preferred embodiment, the lubrication mechanism further includes a third oil inlet branch pipe 20, a second oil return pipe 21, a second check valve 22, and a third oil return pipe 23. One end of the third oil inlet branch pipe 20 is connected to and communicates with the main oil inlet pipe 12, and the other end is connected to and communicates with the oil inlet of the vacuum pump 6. One end of the second oil return pipe 21 is connected to and communicates with the oil return port of the vacuum pump 6, and the other end is connected to and communicates with the auxiliary oil tank 2. One end of the third oil return pipe 23 is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank 2. The second check valve 22 is installed on the third oil return pipe 23. The third oil inlet branch pipe 20 provides lubricating oil to the vacuum pump 6 to ensure the lubrication and cooling required for its normal operation. The second oil return pipe 21 returns the lubricating oil used by the vacuum pump 6 to the auxiliary oil tank 2, realizing the recycling of lubricating oil. The third return oil pipe 23 and the second check valve 22 are designed to, on the one hand, promptly recover excess lubricating oil in the sealed cavity to the auxiliary oil tank 2, and on the other hand, prevent lubricating oil in the auxiliary oil tank 2 from flowing back into the sealed cavity, thus maintaining the reasonable flow and distribution of lubricating oil in the system and ensuring the normal operation of each component.

[0027] In a preferred embodiment, both the first check valve 18 and the second check valve 22 are mechanical check valves, which automatically open and close by relying on the pressure in the direction of oil flow. No additional control is required, the structure is simple and reliable, and the oil return process is guaranteed to proceed stably along the preset path.

[0028] In a preferred embodiment, a bypass oil pipe 24 is also included. The inlet end of the bypass oil pipe 24 is connected to the main inlet oil pipe 12, and the outlet end of the bypass oil pipe 24 is connected to the inlet of the floating ring seal 4. This bypass oil pipe 24 is used to provide emergency lubrication to the floating ring seal 4 when the lubrication control valve 15 fails. During normal operation of the lubrication control valve 15, the bypass oil pipe 24 is in an idle or standby state, with virtually no lubricating oil flow inside (or only a very small amount of seepage). In a hydraulic system, lubricating oil preferentially flows to the channel of least resistance. The bypass oil pipe 24 is designed for emergency backup; its diameter is typically small, or it has a throttling structure at the inlet. When the lubrication control valve 15 of the floating ring seal 4 is normally open, the pressure oil from the main inlet oil pipe 12 flows smoothly to the floating ring seal 4 through the control valve and the second inlet branch pipe 14. This path is designed specifically for normal operation, with minimal flow resistance. The bypass oil pipe 24 is a branch pipe directly connected to the main inlet oil pipe 12. When the second oil inlet branch pipe 14 is unobstructed and the pressure is normal, the lubricating oil will ignore this relatively high-resistance bypass, or only a very small amount of lubricating oil will seep into the bypass pipe due to pressure pulsation and then stagnate there. The bypass oil pipe 24 provides emergency lubrication for the floating ring seal 4, greatly improving the reliability and safety of the system. In the event of a failure of the lubrication control valve 15, the bypass oil pipe 24 can promptly supply lubricating oil to the floating ring seal 4, preventing insufficient lubrication from causing accelerated wear or even damage to the floating ring seal 4, thereby ensuring that the sealing performance of the gearbox 1 is not affected and maintaining normal operation. Its idle or standby state during normal operation does not affect the normal lubrication process of the system, while playing an important role at critical moments, making it a clever and practical design.

[0029] In a preferred embodiment, the lubrication mechanism further includes a level gauge 25, an overflow valve 26, and an overflow pipe 27. The level gauge 25 is installed inside the gearbox 1 and can monitor the level of lubricating oil in the sealed cavity. One end of the overflow pipe 27 is connected to the main oil inlet pipe 12, and the other end is connected to the auxiliary oil tank 2. The overflow valve 26 is installed on the overflow pipe 27. The level gauge 25 can monitor the level of lubricating oil in the sealed cavity in real time, providing accurate data for the control system 28 to adjust the supply or recovery of lubricating oil in a timely manner, preventing the normal operation of the gearbox 1 from being affected by excessively high or low oil levels. The overflow valve 26 and the overflow pipe 27 can overflow excess lubricating oil back to the auxiliary oil tank 2 when there is too much lubricating oil supplied, avoiding problems such as abnormal internal pressure and increased operating resistance of the gearbox 1 caused by excessive lubricating oil, ensuring a reasonable and stable amount of lubricating oil in the system, and improving the stability and reliability of the gearbox 1 operation.

[0030] In a preferred embodiment, the vent valve 9 is a normally closed solenoid valve, and the lubrication control valve 15 is a normally open solenoid valve. The normally closed vent valve 9 ensures the sealing of the cavity during normal operation, preventing outside air from entering and affecting the vacuum level. The vent valve 9 is only opened by the control system 28 under special circumstances, such as when pressure balancing is required. The normally open lubrication control valve 15 ensures a continuous supply of lubricating oil to the floating ring seal 4 and the gear meshing area during normal operation, guaranteeing lubrication. This configuration meets the logical requirements for normal system operation, improves the stability and reliability of system operation, and reduces the risk of failure due to abnormal valve conditions.

[0031] In a preferred embodiment, the hard interlock control between the vacuum pump mechanism and the lubrication mechanism means that the auxiliary normally closed contact of the vacuum pump main contactor of the vacuum pump mechanism is connected in series with the coil of the oil pump main contactor of the lubrication mechanism; and vice versa. When a failure of either mechanism causes its main contactor to lose power, its auxiliary contact directly cuts off the power supply circuit of the other mechanism's main contactor, achieving a fast and safe interlock that is purely hardware-based and does not rely on software programs.

[0032] In a preferred embodiment, the number of floating ring seals is four. The floating ring seals rely on the tiny gap between themselves and the rotating shaft to form a hydrodynamic oil film under the action of lubricating oil. This achieves efficient sealing and avoids direct solid-to-solid contact with the rotating shaft, thereby significantly reducing friction and wear.

[0033] The following details the operation of the vacuum system for the high-efficiency high-speed gearbox 1 of gas turbines: 1. Preparations before system startup: Check component connections: Ensure that all components, including gearbox 1, sealing assembly, auxiliary oil tank 2, vacuum mechanism, pressure balancing mechanism, lubrication mechanism, and control system 28, are securely installed and that the connecting pipes are tight and leak-free. Pay special attention to checking the tight fit between the floating ring seal 4 in the sealing assembly and the shaft hole and rotating shaft, and verify that all oil and air pipe connections are correct.

[0034] Check valve status: Confirm that the air exchange valve 9 is normally closed and the lubrication control valve 15 is normally open. Also check whether the relief valve 26, the first check valve 18, the second check valve 22, etc. are normal and without any jamming.

[0035] Check oil level: Check the lubricating oil level in the sealed chamber of gearbox 1 using level gauge 25 to ensure it is within the normal range. If the level is too low, lubricating oil needs to be added from the unit oil station 29 of the gas turbine through the main oil inlet pipe 12; if the level is too high, excess lubricating oil can be drained into the auxiliary oil tank 2 through overflow valve 26 and overflow pipe 27.

[0036] Check the control system 28: Turn on the power to the control system 28 and check whether the monitoring devices such as the internal pressure sensor 10 and the level gauge 25 can work normally and transmit data accurately. Ensure that the electrical connection between the control system 28 and each mechanism is normal and can effectively control each mechanism.

[0037] 2. System startup: Start the lubrication mechanism: Open the connection valve between the main oil inlet pipe 12 and the gas turbine unit oil station 29. Lubricating oil flows in from the main oil inlet pipe 12. Part of it flows through the first oil inlet branch pipe 13 to the gear meshing area in the gearbox 1 to lubricate the gears; the other part flows through the second oil inlet branch pipe 14, with the lubrication control valve 15 normally open, to each floating ring seal 4 to lubricate the floating ring seal 4. At this time, the third oil inlet branch pipe 20 also delivers lubricating oil to the vacuum pump 6 to meet the lubrication and cooling requirements of the vacuum pump 6.

[0038] Start the vacuum pumping mechanism: Start the vacuum pump 6 to extract air from the sealed chamber of gearbox 1 through the air inlet pipe 5, gradually bringing the sealed chamber to the set negative pressure state. The extracted air is discharged into the auxiliary oil tank 2 through the exhaust pipe 7. During this process, observe whether the vacuum pump 6 operates smoothly and whether there is any abnormal noise or vibration.

[0039] The pressure balancing mechanism is activated: the internal pressure sensor 10 monitors the pressure value inside the sealed cavity in real time and transmits the data to the control system 28. During normal operation, the ventilation valve 9 remains normally closed. The control system adjusts the motor frequency of the vacuum pump based on the pressure data fed back by the internal pressure sensor, and dynamically adjusts the pressure inside the sealed cavity in conjunction with the internal pressure regulating valve: when the pressure inside the cavity is higher than the set negative pressure range, the frequency of the vacuum pump motor is increased to accelerate the pumping speed and reduce the pressure inside the cavity; when the pressure inside the cavity is lower than the set negative pressure range, the frequency of the vacuum pump motor is decreased to slow down the pumping speed, and with the help of the internal pressure regulating valve's micro-injection, the pressure is restored to the set range, and finally the pressure inside the sealed cavity is stabilized and maintained within the target negative pressure range, completing the entire system startup process.

[0040] 3. Monitoring and adjustment during system operation: Pressure Monitoring and Adjustment: Continuously monitor the pressure data fed back by the internal pressure sensor 10. If the pressure inside the sealed chamber rises and approaches the upper limit of the set negative pressure range, appropriately increase the frequency of the vacuum pump motor to accelerate the pumping rate. At the same time, check the gearbox sealing status to confirm whether there is any abnormal leakage. If the leakage is too large and the pressure is difficult to maintain, gradually reduce the opening degree of the internal pressure regulating valve to reduce the leakage into the chamber and help the pressure drop. If the pressure inside the sealed chamber is lower than the lower limit of the set negative pressure range, reduce the frequency of the vacuum pump motor to slow down the pumping rate, and use the internal pressure regulating valve to make a small amount of gas replenishment to allow the pressure inside the chamber to rise back to the set range.

[0041] Oil level monitoring and adjustment: The lubricating oil level in the sealed chamber of gearbox 1 is monitored in real time via level gauge 25. When the level rises above the upper limit, oil pump 17 starts, draining excess lubricating oil into auxiliary oil tank 2 through the first return oil pipe 16, oil pump 17, first check valve 18, and thermal expansion joint 19. If the level drops to the lower limit, check whether the lubrication system is supplying oil normally, such as whether the main oil inlet pipe 12 is blocked or whether the lubrication control valve 15 is malfunctioning.

[0042] Equipment status monitoring: Observe the operating status of each mechanism and equipment, such as the operating sound and temperature of vacuum pump 6 and oil pump 17, and the opening and closing status of each valve. At the same time, pay attention to checking for leaks in the sealing components. If obvious leakage is found at the floating ring seal 4, the machine must be stopped immediately for inspection and repair.

[0043] 4. System Failure Handling: Vacuum pump 6 malfunction: If vacuum pump 6 malfunctions, the oil pump 17 in the lubrication mechanism will automatically stop due to the hard interlock between the vacuuming mechanism and the lubrication mechanism. Simultaneously, the control system 28 will trigger the ventilation valve 9 to open rapidly, allowing the sealed chamber to communicate with the outside atmosphere, balancing the pressure inside the chamber, and preventing abnormal pressure within the sealed chamber due to the vacuum pump 6 malfunction. In this case, vacuum pump 6 should be shut down and repaired or replaced.

[0044] Oil pump 17 malfunction: When oil pump 17 malfunctions, the hard interlock control automatically stops the vacuum pump 6 to prevent oil from accumulating in the sealed chamber due to the inability to discharge oil. Simultaneously, the vent valve 9 opens to balance the pressure. Oil pump 17 needs to be repaired or replaced promptly to ensure that lubricating oil can be normally introduced from gearbox 1 into auxiliary oil tank 2.

[0045] Lubrication control valve 15 malfunction: If lubrication control valve 15 fails, bypass oil pipe 24 will activate, and lubricating oil from main inlet pipe 12 will provide emergency lubrication to floating ring seal 4 through bypass oil pipe 24 to maintain the normal operation of floating ring seal 4. In this case, lubrication control valve 15 should be repaired or replaced as soon as possible to restore the normal lubrication path.

[0046] Additionally, after the unit has been running for a period of time, it may reach the maintenance cycle or the vacuum pump may be unable to meet the required negative pressure range. In this case, the leakage rate of the sealed cavity increases due to the operation of the gearbox. The leakage rate can be reduced by adjusting the opening degree of the internal pressure regulating valve, thereby enabling the vacuum pump to operate normally within the required negative pressure range.

[0047] 5. System shutdown: To shut down the vacuum pumping mechanism: first turn off vacuum pump 6 to stop pumping air from the sealed cavity, allowing the pressure in the sealed cavity to gradually return to near atmospheric pressure.

[0048] Shut down the lubrication system: Close the connecting valve between the main oil inlet pipe 12 and the gas turbine oil station 29 to stop the supply of lubricating oil. After the lubricating oil in the gearbox 1 has basically flowed back to the auxiliary oil tank 2, turn off the oil pump 17.

[0049] Pressure balancing operation: After confirming that vacuum pump 6 and oil pump 17 have stopped running, open the ventilation valve 9 to fully connect the sealed cavity with the outside atmosphere and ensure that the pressure inside the cavity is consistent with the outside pressure.

[0050] Inspection and maintenance: After the system is shut down, check each component for damage, leaks, etc., and perform necessary maintenance on the equipment to prepare for the next use.

[0051] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A vacuum system for a high-efficiency, high-speed gearbox of a gas turbine, characterized in that: include: A gearbox containing meshing gears, with the shafts of each gear passing through and extending out of the gearbox; A sealing assembly is sleeved on the outer periphery of each shaft extending out of the gearbox to seal the fit gap between the shaft and the gearbox housing, thereby forming a sealed cavity inside the gearbox. Auxiliary oil tank, which is used to return the received lubricating oil to the unit oil station of the gas turbine; A vacuuming mechanism, wherein the suction end of the vacuuming mechanism is connected and communicates with the gearbox to maintain a set negative pressure state inside the sealed cavity, and the exhaust end of the vacuuming mechanism is connected and communicates with the auxiliary oil tank. A pressure balancing mechanism, which is connected to the sealed cavity, is used to selectively connect the sealed cavity to the outside atmosphere; The lubrication mechanism is used to deliver lubricating oil to the gear meshing area and the lubrication part of the sealing assembly in the gearbox, and can cooperate with the negative pressure state of the sealed cavity to allow the lubricating oil to be introduced from the gearbox into the auxiliary oil tank. The control system is electrically connected to the vacuuming mechanism, the pressure balancing mechanism, and the lubrication mechanism, and is capable of putting the vacuuming mechanism or the lubrication mechanism under hard interlock control so that if one of the vacuuming mechanism or the lubrication mechanism fails, the other mechanism in the vacuuming mechanism or the lubrication mechanism will be automatically stopped.

2. The vacuum system for a high-efficiency, high-speed gearbox for a gas turbine according to claim 1, characterized in that: The sealing assembly includes two sealing partitions and multiple floating ring seals. The two sealing partitions are symmetrically arranged inside the gearbox. The sealing partitions are provided with shaft holes for the shaft of the gear to pass through. The floating ring seals are installed between the inner wall of the shaft hole and the outer wall of the shaft to enclose the space between the two sealing partitions inside the gearbox to form the sealed cavity.

3. The vacuum system for a high-efficiency, high-speed gearbox of a gas turbine according to claim 2, characterized in that: The vacuum pumping mechanism includes a vacuum pump, an inlet pipe, and an exhaust pipe. One end of the inlet pipe is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the inlet of the vacuum pump. One end of the exhaust pipe is connected to and communicates with the exhaust port of the vacuum pump, and the other end is connected to and communicates with the auxiliary oil tank. The vacuum pump is connected to and communicates with the lubrication mechanism to obtain lubricating oil for lubrication and cooling.

4. The vacuum system for a high-efficiency, high-speed gearbox for a gas turbine according to claim 3, characterized in that: The pressure balancing mechanism includes a ventilation pipeline, a ventilation valve, an internal pressure sensor, and an internal pressure regulating valve. The internal pressure sensor is installed inside the sealed cavity to monitor the pressure value inside the sealed cavity and is electrically connected to the control system. One end of the ventilation pipeline is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank. The ventilation valve is installed on the ventilation pipeline and is electrically connected to the control system. The internal pressure regulating valve is installed on the ventilation pipeline and is connected in parallel with the ventilation valve. The vacuum pump can change the motor frequency according to the pressure value monitored by the internal pressure sensor to stably maintain the pressure inside the sealed cavity within a set negative pressure range.

5. The vacuum system for a high-efficiency, high-speed gearbox for a gas turbine according to claim 4, characterized in that: The lubrication mechanism includes a main oil inlet pipe, a first oil inlet branch pipe, a second oil inlet branch pipe, a lubrication control valve, a first oil return pipe, an oil pump, a first check valve, and a thermal expansion joint. One end of the main oil inlet pipe is connected to and communicates with the unit oil station of the gas turbine, and the other end is connected to and communicates with the first oil inlet branch pipe and the second oil inlet branch pipe. The end of the first oil inlet branch pipe away from the main oil inlet pipe extends to the gear meshing area in the gearbox. The end of the second oil inlet branch pipe away from the main oil inlet pipe extends to each of the floating ring seals. The lubrication control valve is disposed on the second oil inlet branch pipe and is electrically connected to the control system. One end of the first oil return pipe is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank. The oil pump, the first check valve, and the thermal expansion joint are sequentially disposed on the first oil return pipe along the flow direction of the lubricating oil, and the oil pump is electrically connected to the control system.

6. The vacuum system for a high-efficiency, high-speed gearbox for a gas turbine according to claim 5, characterized in that: The lubrication mechanism further includes a third oil inlet branch pipe, a second oil return pipe, a second check valve, and a third oil return pipe. One end of the third oil inlet branch pipe is connected to and communicates with the main oil inlet pipe, and the other end is connected to and communicates with the oil inlet of the vacuum pump. One end of the second oil return pipe is connected to and communicates with the oil return port of the vacuum pump, and the other end is connected to and communicates with the auxiliary oil tank. One end of the third oil return pipe is connected to and communicates with the sealed cavity, and the other end is connected to and communicates with the auxiliary oil tank. The second check valve is installed on the third oil return pipe.

7. The vacuum system for a high-efficiency, high-speed gearbox for a gas turbine according to claim 6, characterized in that: It also includes a bypass oil pipe, the oil inlet of which is connected to the main oil inlet pipe, and the oil outlet of which is connected to the oil inlet of the floating ring seal, for providing emergency lubrication to the floating ring seal when the lubrication control valve fails.

8. The vacuum system for a high-efficiency, high-speed gearbox for a gas turbine according to claim 7, characterized in that: The lubrication mechanism also includes a level gauge, an overflow valve, and an overflow pipe. The level gauge is installed inside the gearbox and can monitor the level of the lubricating oil in the sealed cavity. One end of the overflow pipe is connected to the main oil inlet pipe and the other end is connected to the auxiliary oil tank. The overflow valve is installed on the overflow pipe.

9. The vacuum system for a high-efficiency, high-speed gearbox for a gas turbine according to claim 8, characterized in that: The air exchange valve is a normally closed solenoid valve, and the lubrication control valve is a normally open solenoid valve.

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