A pod propeller rudder seal system with monitoring and leakage recovery functions

Abstract

The present application relates to a kind of pod propeller steering sealing system with monitoring and leakage recovery function, including steering sealing device body, pressurized oil lubricating device, gas supply device and leakage recovery device, pressurized oil lubricating device is connected steering sealing device body, for providing lubricating oil, for the lip seal ring inside steering sealing device body provides lubricating medium, while providing suitable oil pressure for the sealing cavity inside steering sealing device body, prevent lip seal ring failure when seawater leakage or lubricating oil leakage;Gas supply device is connected pressurized oil lubricating device and steering sealing device body, for providing compressed air, adjust and monitor the pressure and flow of required compressed air;Leakage recovery device is connected steering sealing device body, for monitoring the leakage of steering sealing device body, the leakage of steering sealing device body is discharged to ship body collection box.This steering sealing system further improves the reliability of pod propeller, reduces the pollution of lubricating oil to environment.

Description

Technical Field

[0001] This invention relates to a marine propulsion system, and more particularly to a podded propulsion rudder sealing system. Background Technology

[0002] In recent years, ship electric propulsion technology has developed rapidly. Podded propulsion systems have become the preferred choice for main propulsion systems of electric propulsion ships due to their advantages such as flexible operation, simple structure, low vibration and noise, and small cabin space occupation.

[0003] The podded propulsion system suspends the underwater propulsion module on the outside of the hull via a swivel module, allowing for 360° rudder rotation. Therefore, a rudder seal is required to prevent seawater from entering the swivel module through the swivel shaft, which could cause rudder mechanism failure. Simultaneously, it must prevent lubricating oil inside the swivel module from leaking into the seawater and polluting the marine environment. Thus, the reliability of the rudder seal greatly determines the operational stability of the podded propulsion system.

[0004] Currently, there are two main types of rudder seals used in podded propulsion systems both domestically and internationally: The first type uses a three-lip seal structure, with all three lip seals facing the external seawater, forming two sealed cavities. During installation, these cavities are filled with seawater-resistant grease and equipped with a system for periodic grease replenishment. The second type uses a four-lip seal structure, with the outer two lip seals facing the external seawater and the inner two lip seals facing the slewing module, forming three sealed cavities. During installation, the outer two cavities are filled with seawater-resistant grease, and the inner cavity is filled with grease, each equipped with a system for periodic grease replenishment. Existing rudder seal systems are simple in structure, require fewer supporting equipment, and are relatively reliable, but lack safety redundancy. They suffer from problems such as lubricant leakage into seawater, failure to meet environmental regulations for specific navigation areas, and inability to monitor seal failure. Therefore, there is a need to develop a podded propulsion rudder seal system with higher reliability and environmental performance. The rudder sealing system employs a unique arrangement of multiple lip seals. When these lip seals fail, the equipped pressurized oil lubrication device, air supply device, and leakage recovery device activate. These devices monitor for seawater leakage into the sealing system, promptly detecting lip seal failure and draining any leaked seawater into the ship's sludge tank. This prevents external seawater from entering the rudder module and causing lubrication failure, while also preventing lubricating oil leakage into the seawater. This rudder sealing system further improves the reliability of podded propulsion systems, reduces lubricant pollution, and contributes to the technological advancement and widespread application of podded propulsion systems. Summary of the Invention

[0005] This invention provides a steering seal system with monitoring and leak recovery functions, suitable for podded propulsion systems. This steering seal system features redundancy to ensure seal reliability and extend service life. It also features leak recovery, allowing leaked materials to be discharged from the seal system, ensuring safe and reliable operation of the steering mechanism while preventing environmental pollution. Furthermore, the system has a monitoring function; through pre-installed sensors, it can monitor the operating status of the steering seal system, thereby determining its operational condition and developing condition-based maintenance strategies.

[0006] To achieve the above objectives, the technical solution of the present invention is: a podded propeller steering sealing system with monitoring and leakage recovery functions, comprising a steering sealing device body, a pressurized oil lubrication device, an air supply device, and a leakage recovery device. The pressurized oil lubrication device is connected to the steering sealing device body and is used to provide lubricating oil to provide a lubricating medium for the lip seal ring inside the steering sealing device body, while providing appropriate oil pressure to the sealing cavity inside the steering sealing device body to prevent seawater leakage or lubricating oil leakage when the lip seal ring fails. The air supply device is connected to the pressurized oil lubrication device and the steering sealing device body and is used to provide compressed air, adjust and monitor the required compressed air pressure and flow rate. The leakage recovery device is connected to the steering sealing device body and is used to monitor the leakage of the steering sealing device body and discharge the leaked material from the steering sealing device body to the hull collection tank.

[0007] Furthermore, the main body of the steering seal device consists of a steering seal mounting base, lip seal rings, spacer rings, and sealing pressure plates, wherein: lip seal ring #1 is arranged facing the external seawater, lip seal ring #2 is arranged facing the rotating module, lip seal ring #3 is arranged facing the external seawater, and lip seal ring #4 is arranged facing the rotating module; the four lip seal rings form three sealing chambers, wherein sealing chamber #1 is connected to the air supply device and the leakage recovery device, and compressed air is introduced during operation; sealing chamber #2 is connected to the pressurized oil lubrication device, and pressurized lubricating oil is introduced during operation; lip seal ring #1 is lubricated by external seawater, lip seal rings #2 and #3 are lubricated by pressurized oil, and lip seal ring #4 is lubricated by lubricating oil inside the rotating module.

[0008] Furthermore, the compressed air pressure is not greater than the sum of the back pressure that the #1 lip seal can withstand and the external seawater pressure; the pressurized lubricating oil pressure is greater than the seawater pressure outside the #1 lip seal and the lubricating oil pressure outside the #4 lip seal.

[0009] Furthermore, the pressurized oil lubrication device consists of a sealed oil tank, a level sensor L1, a safety valve SA1, ball valves VB1, VB2, VB3, and an air filter F1. The sealed oil tank is used to store lubricating oil. The level sensor L1, safety valve SA1, ball valve VB1, and air filter F1 are installed on the top, and ball valves VB2 and VB3 are installed on the bottom. The level sensor L1 is used to monitor the level of the sealed oil tank. The safety valve SA1 is used to ensure that the internal pressure of the sealed oil tank does not exceed the safe value. The ball valves VB1 and air filter F1 are used to switch the pressurized sealed oil tank to a gravity oil tank when the air supply device cannot supply air, so as to continue to supply lubricating oil to the steering seal device body. The ball valve VB2 is used to control the on / off supply of oil to the steering seal device body, and the ball valve VB3 is used to discharge the lubricating oil inside the sealed oil tank.

[0010] Furthermore, the air supply device consists of an air compressor P1, a ball valve VB4, a pressure sensor PT1, a pressure reducing valve V1, a flow meter QT1, a throttle valve S1, a pressure sensor PT2, a ball valve VB5, a filter AF1, a dryer AD1, a pressure reducing valve V2, a pressure sensor PT3, and a ball valve VB6. The air supply device includes two air paths. One air path, in sequence, consists of an air compressor P1, a ball valve VB4, a pressure sensor PT1, a pressure reducing valve V1, a flow meter QT1, a throttle valve S1, a pressure sensor PT2, and a ball valve VB5, leading to the No. 2 sealing chamber of the steering wheel sealing device body. The other air path, in sequence, consists of an air compressor P1, a ball valve VB4, a filter AF1, a dryer AD1, a pressure reducing valve V2, a pressure sensor PT3, and a ball valve VB6, leading to the sealing oil tank of the pressurized oil lubrication device.

[0011] Furthermore, air compressor P1 is used to provide compressed air to the system; ball valve VB4 is used to control the on / off of air supply from the air compressor; ball valve VB5 is used to control the on / off of air supply to the steering wheel seal body; ball valve VB6 is used to control the on / off of air supply to the pressurized oil lubrication device; pressure reducing valve V1 is used to adjust the compressed air pressure to the steering wheel seal body; pressure reducing valve V2 is used to adjust the compressed air pressure to the pressurized oil lubrication device; throttle valve S1 is used to regulate the compressed air flow rate to the steering wheel seal body; flow meter QT1 is used to monitor whether the compressed air flow rate to the steering wheel seal body is normal; filter AF1 is used to filter the compressed air entering the pressurized oil lubrication device; dryer AD1 is used to dry the compressed air entering the pressurized oil lubrication device; pressure sensor PT1 is used to monitor the air supply pressure of air compressor P1; pressure sensor PT2 is used to monitor the compressed air pressure entering the steering wheel seal body; and pressure sensor PT3 is used to monitor the compressed air pressure entering the pressurized oil lubrication device.

[0012] Furthermore, the leakage recovery device consists of an oil-water collection tank, a level sensor L2, a ball valve VB7, and a throttle valve S2. The oil-water collection tank is used to collect leaked liquid discharged from the steering wheel sealing device body. The level sensor L2 is installed at the top, and the ball valve VB7 is installed at the bottom. The level sensor L2 is used to monitor the liquid level in the oil-water collection tank. The ball valve VB7 is used to discharge the lubricating oil inside the oil-water collection tank. The throttle valve S2 is used to separate the liquid carried out by the compressed air from the steering wheel sealing device body.

[0013] Furthermore, when the oil level in the sealing tank decreases, the level sensor L1 issues a low oil level warning, reminding maintenance personnel to add lubricating oil, and also issues a warning that either the #2 or #3 lip seal may have failed. If the level sensor L2 simultaneously indicates that liquid has been collected in the oil-water collection tank, it is determined that the #2 lip seal has failed. If the level sensor L2 does not indicate that liquid has been collected in the oil-water collection tank, and the sealing oil tank is refilled with lubricating oil, the level sensor L1 issues a low oil level warning again within a short period of time, it is determined that the #3 lip seal has failed. If neither of the above two situations applies, it is normal lubricating oil consumption of the steering seal device body.

[0014] Furthermore, when liquid is collected in the oil-water collection tank, the level sensor L2 issues a leakage warning for the steering seal device, alerting maintenance personnel that either lip seal #1 or lip seal #2 has failed. If the level sensor L1 simultaneously issues a low oil level warning for the sealing tank, it can be determined that lip seal #2 has failed; otherwise, lip seal #1 has failed.

[0015] The beneficial effects of this invention are:

[0016] The rudder sealing system of the present invention includes a rudder sealing device body, a pressurized oil lubrication device, an air supply device, and a leakage recovery device, which has redundancy functions, improves the reliability of the podded propulsion system, and extends its service life.

[0017] The main body of the rudder sealing device of the present invention consists of three sealing cavities composed of four specially oriented lip seals. When any two of the lip seals have normal sealing function, external seawater cannot leak into the slewing module and thus damage the rudder mechanism. At the same time, the lubricating oil of the slewing module and the main body of the rudder sealing device cannot leak into the seawater and pollute the environment.

[0018] The air supply device of the present invention includes two air paths, which can adjust and process compressed air separately to meet the air demand of podded propulsion under different ship types or different ship drafts, and has good versatility and environmental adaptability.

[0019] The pressurized oil lubrication device and leakage recovery device of the present invention are respectively equipped with liquid level sensor L1 and liquid level sensor L2. The liquid level sensor L1 monitors the usage status of lip seal #2 and lip seal #3, and the liquid level sensor L2 monitors the usage status of lip seal #1 and lip seal #2. By combining the monitoring signals of liquid level sensor L1 and liquid level sensor L2, the failed seal can be identified, and a maintenance strategy can be formulated accordingly. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the steering wheel sealing system;

[0021] Figure 2 This is a schematic diagram of the main body of the steering wheel sealing device;

[0022] Figure 3 This is a schematic diagram of a pressurized oil lubrication device;

[0023] Figure 4 This is a schematic diagram of the gas supply device;

[0024] Figure 5 This is a schematic diagram of a leakage recovery device. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] like Figures 1 to 5 As shown in the figure, an embodiment of the present invention provides a podded thruster rudder sealing system with monitoring and leakage recovery functions, including a rudder sealing device body 1, a pressurized oil lubrication device 2, an air supply device 3, and a leakage recovery device 4, as shown in the figure. Figure 1 As shown.

[0027] The pressurized oil lubrication device 2 is connected to the steering seal device body 1, providing lubricating oil to the lip seal ring inside the steering seal device body 1, and providing appropriate oil pressure to the sealing cavity inside the steering seal device body 1 to prevent seawater or lubricating oil leakage when the lip seal ring fails; the air supply device 3 is connected to the pressurized oil lubrication device 2 and the steering seal device body 1, and is used to provide compressed air, adjust and monitor the required compressed air pressure and flow rate; the leakage recovery device 4 is connected to the steering seal device body 1, and is used to monitor the leakage of the steering seal device body 1 and discharge the leaked material from the steering seal device body 1 to the hull collection box.

[0028] like Figure 2As shown, the main body 1 of the steering seal device mainly consists of a steering seal mounting base 1a, a lip seal ring 1b, a spacer ring 1c, and a sealing pressure plate 1d. Lip seal ring 1b-1 (1#) faces the external seawater, lip seal ring 1b-2 (2#) faces the steering module, lip seal ring 1b-3 (3#) faces the external seawater, and lip seal ring 1b-4 (4#) faces the steering module. These four lip seal rings 1b form three sealing chambers (Sealing Chamber I, Sealing Chamber II, and Sealing Chamber III). Sealing Chamber I (1#) connects to the air supply device 3 and the leakage recovery device 4. Compressed air is introduced during operation, and the compressed air pressure should not exceed the sum of the back pressure that lip seal ring 1b-1 can withstand and the external seawater pressure. Sealing Chamber II (2#) connects to the pressurized oil lubrication device 2. Pressurized lubricating oil is introduced during operation, and the oil pressure here should be greater than the seawater pressure outside lip seal ring 1b-1 and the lubricating oil pressure outside lip seal ring 1b-4. #1 lip seal 1b-1 is lubricated by external seawater, #2 lip seal 1b-2 and #3 lip seal 1b-3 are lubricated by pressurized oil, and #4 lip seal 1b-4 is lubricated by the lubricating oil inside the rotary module.

[0029] like Figure 3 As shown, the pressurized oil lubrication device 2 mainly consists of a sealed oil tank, a level sensor L1, a safety valve SA1, ball valves VB1, VB2, VB3, and an air filter F1. The sealed oil tank stores lubricating oil. The top is equipped with the level sensor L1, safety valve SA1, ball valve VB1, and air filter F1, while the bottom is equipped with ball valves VB2 and VB3. The level sensor L1 monitors the oil level in the sealed oil tank. The safety valve SA1 ensures that the internal pressure of the sealed oil tank does not exceed a safe value. Ball valves VB1 and air filter F1 are used to switch the pressurized sealed oil tank to a gravity oil tank when the air supply device fails to provide air, continuing to supply lubricating oil to the steering seal device body. Ball valve VB2 controls the on / off supply of oil to the steering seal device body, and ball valve VB3 discharges the lubricating oil from inside the sealed oil tank.

[0030] like Figure 4As shown, the air supply device 3 mainly consists of an air compressor P1, ball valve VB4, pressure sensor PT1, pressure reducing valve V1, flow meter QT1, throttle valve S1, pressure sensor PT2, ball valve VB5, filter AF1, dryer AD1, pressure reducing valve V2, pressure sensor PT3, and ball valve VB6. The air supply device includes two air paths. One air path, in sequence, consists of air compressor P1, ball valve VB4, pressure sensor PT1, pressure reducing valve V1, flow meter QT1, throttle valve S1, pressure sensor PT2, and ball valve VB5, leading to the #2 sealing chamber of the steering wheel sealing device body. The other air path, in sequence, consists of air compressor P1, ball valve VB4, filter AF1, dryer AD1, pressure reducing valve V2, pressure sensor PT3, and ball valve VB6, leading to the sealing oil tank of the pressurized oil lubrication device. The air compressor provides compressed air to the system. Ball valve VB4 controls the on / off supply of air from the air compressor. Ball valve VB5 controls the on / off supply of air to the steering wheel seal body. Ball valve VB6 controls the on / off supply of air to the pressurized oil lubrication device. Pressure reducing valve V1 adjusts the compressed air pressure to the steering wheel seal body. Pressure reducing valve V2 adjusts the compressed air pressure to the pressurized oil lubrication device. Throttle valve S1 regulates the compressed air flow rate to the steering wheel seal body. Flow meter QT1 monitors whether the compressed air flow rate to the steering wheel seal body is normal. Filter AF1 filters the compressed air entering the pressurized oil lubrication device. Dryer AD1 dries the compressed air entering the pressurized oil lubrication device. Pressure sensor PT1 monitors the air supply pressure from air compressor P1. Pressure sensor PT2 monitors the compressed air pressure entering the steering wheel seal body. Pressure sensor PT3 monitors the compressed air pressure entering the pressurized oil lubrication device.

[0031] like Figure 5 As shown, the leakage recovery device 4 consists of an oil-water collection tank, a level sensor L2, a ball valve VB7, and a throttle valve S2. The oil-water collection tank collects leaked liquid discharged from the steering wheel seal body. The level sensor L2 is installed at the top, and the ball valve VB7 is installed at the bottom. The level sensor L2 monitors the liquid level in the oil-water collection tank, the ball valve VB7 drains the lubricating oil from inside the tank, and the throttle valve S2 better separates the liquid carried by compressed air from the steering wheel seal body.

[0032] When the oil level in the sealing oil tank drops, the level sensor L1 issues a low oil level warning, reminding maintenance personnel to add lubricating oil, and also indicates that either the #2 or #3 lip seal may have failed. If the level sensor L2 simultaneously indicates that liquid has been collected in the oil-water collection tank, it is determined that the #2 lip seal has failed. If the level sensor L2 does not indicate that liquid has been collected in the oil-water collection tank, and the sealing oil tank is refilled with lubricating oil, the level sensor L1 issues a low oil level warning again within a short period of time, it is determined that the #3 lip seal has failed. If neither of the above two situations applies, it is normal lubricating oil consumption of the steering seal device body.

[0033] When liquid is collected in the oil-water collection tank, the level sensor L2 issues a leakage warning for the steering seal device, alerting maintenance personnel that either lip seal #1 or lip seal #2 has failed. If the level sensor L1 simultaneously issues a low oil level warning for the sealing tank, it can be determined that lip seal #2 has failed; otherwise, lip seal #1 has failed.

Claims

1. A podded thruster steering seal system with monitoring and leakage recovery functions, characterized in that: The system includes a steering seal device body, a pressurized oil lubrication device, an air supply device, and a leakage recovery device. The pressurized oil lubrication device is connected to the steering seal device body and provides lubricating oil to the lip seal ring inside the steering seal device body. It also provides appropriate oil pressure to the sealing cavity inside the steering seal device body to prevent seawater or lubricating oil leakage in case of lip seal ring failure. The air supply device is connected to the pressurized oil lubrication device and the steering seal device body and provides compressed air, adjusting and monitoring the required compressed air pressure and flow rate. The leakage recovery device is connected to the steering seal device body and monitors leakage in the steering seal device body, discharging leaked material into a hull collection tank. The steering seal device body consists of a steering seal mounting base, a lip seal ring, a spacer ring, and a sealing pressure plate. Specifically: lip seal ring #1 faces the external seawater, lip seal ring #2 faces the steering module, and lip seal ring #3... The four lip seals are arranged with the outer seawater facing outwards, and the 4# lip seal is arranged with the rotating module facing outwards. The four lip seals form three sealing chambers. Sealing chamber 1 connects to the air supply device and the leakage recovery device, and is circulated with compressed air during operation. Sealing chamber 2 connects to the pressurized oil lubrication device, and is circulated with pressurized lubricating oil during operation. Lip seal 1 is lubricated by the outer seawater, lip seals 2 and 3 are lubricated by pressurized oil, and lip seal 4 is lubricated by the lubricating oil inside the rotating module. The leakage recovery device consists of an oil-water collection tank, a level sensor L2, a ball valve VB7, and a throttle valve S2. The oil-water collection tank collects leaked liquid discharged from the rotating sealing device body. A level sensor L2 is installed at the top, and a ball valve VB7 is installed at the bottom. The level sensor L2 monitors the liquid level in the oil-water collection tank, the ball valve VB7 discharges the lubricating oil from inside the oil-water collection tank, and the throttle valve S2 separates the liquid carried out by the compressed air from the rotating sealing device body.

2. The podded propulsion steering sealing system with monitoring and leakage recovery functions according to claim 1, characterized in that: The compressed air pressure is not greater than the sum of the back pressure that the No. 1 lip seal can withstand and the external seawater pressure; the pressurized lubricating oil pressure is greater than the seawater pressure outside the No. 1 lip seal and the lubricating oil pressure outside the No. 4 lip seal.

3. The podded propulsion steering sealing system with monitoring and leakage recovery functions according to claim 1, characterized in that: The pressurized oil lubrication device consists of a sealed oil tank, a level sensor L1, a safety valve SA1, ball valves VB1, VB2, VB3, and an air filter F1. The sealed oil tank stores lubricating oil. The top is equipped with the level sensor L1, safety valve SA1, ball valve VB1, and air filter F1, while the bottom is equipped with ball valves VB2 and VB3. The level sensor L1 monitors the level of the sealed oil tank. The safety valve SA1 ensures that the internal pressure of the sealed oil tank does not exceed a safe value. The ball valves VB1 and F1 switch the pressurized sealed oil tank to a gravity oil tank when the air supply device fails to supply air, continuing to provide lubricating oil to the steering seal device body. The ball valve VB2 controls the on / off supply of oil to the steering seal device body, and the ball valve VB3 discharges the lubricating oil from inside the sealed oil tank.

4. The podded propulsion steering sealing system with monitoring and leakage recovery functions according to claim 1, characterized in that: The air supply device consists of an air compressor P1, a ball valve VB4, a pressure sensor PT1, a pressure reducing valve V1, a flow meter QT1, a throttle valve S1, a pressure sensor PT2, a ball valve VB5, a filter AF1, a dryer AD1, a pressure reducing valve V2, a pressure sensor PT3, and a ball valve VB6. The air supply device includes two air paths. One air path, in sequence, consists of an air compressor P1, a ball valve VB4, a pressure sensor PT1, a pressure reducing valve V1, a flow meter QT1, a throttle valve S1, a pressure sensor PT2, and a ball valve VB5, leading to the No. 2 sealing chamber of the steering wheel sealing device body. The other air path, in sequence, consists of an air compressor P1, a ball valve VB4, a filter AF1, a dryer AD1, a pressure reducing valve V2, a pressure sensor PT3, and a ball valve VB6, leading to the sealing oil tank of the pressurized oil lubrication device.

5. The podded propulsion steering sealing system with monitoring and leakage recovery functions according to claim 4, characterized in that: Air compressor P1 is used to supply compressed air to the system. Ball valve VB4 is used to control the on / off of air supply from the air compressor. Ball valve VB5 is used to control the on / off of air supply to the steering wheel seal body. Ball valve VB6 is used to control the on / off of air supply to the pressurized oil lubrication device. Pressure reducing valve V1 is used to adjust the compressed air pressure to the steering wheel seal body. Pressure reducing valve V2 is used to adjust the compressed air pressure to the pressurized oil lubrication device. Throttle valve S1 is used to regulate the compressed air flow rate to the steering wheel seal body. Flow meter QT1 is used to monitor whether the compressed air flow rate to the steering wheel seal body is normal. Filter AF1 is used to filter the compressed air entering the pressurized oil lubrication device. Dryer AD1 is used to dry the compressed air entering the pressurized oil lubrication device. Pressure sensor PT1 is used to monitor the air supply pressure of air compressor P1. Pressure sensor PT2 is used to monitor the compressed air pressure entering the steering wheel seal body. Pressure sensor PT3 is used to monitor the compressed air pressure entering the pressurized oil lubrication device.

6. The podded propulsion steering sealing system with monitoring and leakage recovery functions according to claim 1, characterized in that: When the oil level in the sealing oil tank drops, the level sensor L1 issues a low oil level warning, reminding maintenance personnel to add lubricating oil, and also indicates that either the #2 or #3 lip seal may have failed. If the level sensor L2 simultaneously indicates that liquid has been collected in the oil-water collection tank, it is determined that the #2 lip seal has failed. If the level sensor L2 does not indicate that liquid has been collected in the oil-water collection tank, and the sealing oil tank is refilled with lubricating oil, the level sensor L1 issues a low oil level warning again within a short period of time, it is determined that the #3 lip seal has failed. If neither of the above two situations applies, it is normal lubricating oil consumption of the steering seal device body.

7. The podded propulsion steering sealing system with monitoring and leakage recovery functions according to claim 1, characterized in that: When liquid is collected in the oil-water collection tank, the liquid level sensor L2 issues a leakage warning for the steering seal device, alerting maintenance personnel that either the #1 or #2 lip seal has failed. If the liquid level sensor L1 simultaneously issues a low liquid level warning for the sealing oil tank, it can be determined that the #2 lip seal has failed; otherwise, it indicates that the #1 lip seal has failed.

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