Air sealing system for ship stern shaft sealing device

Abstract

The invention discloses an air sealing system for a ship stern shaft sealing device, which relates to the technical field of ship stern shaft sealing and comprises a shaft tube body, a sealing structure is mounted at the end of the shaft tube body, an inlet pressure sensor is mounted at the air inlet end of the sealing structure, and a control mechanism is mounted on the inlet pressure sensor through a pipeline. A front oil tank mechanism is installed at the tail end of the shaft tube body, and the control mechanism comprises a control frame, an air control unit, a discharging and collecting unit, a lubricating oil control unit, a pump body and a master controller. Through the arrangement mode that the sealing mechanism and the control mechanism are matched, the pressure of each cavity is dynamically adjusted in a stepped mode according to the ship draft depth and the working condition, a reliable pressure gradient barrier is constructed, seawater invasion and lubricating oil leakage are effectively prevented, the sealing rings and the shaft necks are in a non-contact or micro-contact state, and the service life of the sealing rings and the shaft necks is prolonged. Therefore, mechanical friction and abrasion are reduced fundamentally, and the service life of the sealing ring is prolonged.

Description

Technical Field

[0001] This invention relates to the field of ship stern shaft sealing technology, and in particular to an air sealing system for ship stern shaft sealing devices. Background Technology

[0002] The stern shaft seal is a critical component of a ship's propulsion system. Its core function is to prevent seawater from entering the hull while ensuring that the lubricating oil in the stern shaft bearing does not leak, thus guaranteeing the safe, reliable, and environmentally friendly operation of the propulsion system. Among various sealing methods, air seals are widely used.

[0003] In practical use, the pressure control of the air chamber in existing typical ship stern shaft air sealing systems relies on mechanical pressure regulating valves and relief valves. These valves have limited response speed and accuracy, and cannot accurately track changes in external water pressure caused by dynamic conditions such as ship undulation and turning. This results in large fluctuations in the pressure difference between the air chamber and the lubricating oil chamber. If the pressure difference is too small, it is insufficient to effectively block seawater; if the pressure difference is too large, it will force the sealing ring lip to excessively fit against the stern shaft, exacerbating abnormal wear and aging, and affecting the sealing ring's lifespan. Furthermore, the lubricating oil relies solely on gravity for supply, resulting in low oil flow rate and weak circulation power. This leads to poor lubricating oil flow near the bearing friction pair, making it difficult to remove the heat generated by the friction between the bearing and the seal in a timely and effective manner. This causes the temperature in the lubricating oil chamber to easily accumulate and rise, reducing lubrication performance and causing thermal aging of the sealing ring material, further damaging the overall reliability and durability of the seal. Summary of the Invention

[0004] The purpose of this invention is to provide an air sealing system for a ship stern shaft sealing device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an air sealing system for a ship stern shaft sealing device, comprising a shaft tube body, a sealing structure installed at the end of the shaft tube body, an inlet pressure sensor installed at the air inlet end of the sealing structure, a control mechanism installed through a pipeline on the inlet pressure sensor, and a front-mounted oil tank mechanism installed at the tail end of the shaft tube body, the control mechanism comprising:

[0006] The control frame is a frame box structure.

[0007] An air control unit is mounted on the top of the control frame and is used to connect with an inlet pressure sensor to control the air pressure in the annular cavity of the sealed structure.

[0008] A leakage collection unit is installed at the corner of the bottom of the control frame. The leakage collection unit is used for the classified collection of leaked liquid from the sealing structure.

[0009] An oil control unit is installed in the middle of the control frame and is used for cooling control of the lubricating oil in the shaft tube body.

[0010] Pump body, which is connected to the discharge collection unit;

[0011] A main controller, which is mounted at the bottom of the control frame, is used for the overall control of the system.

[0012] Preferably, the sealing structure includes:

[0013] The first annular cavity is installed at the end of the shaft tube body that is close to the seawater.

[0014] The second annular cavity is installed on the side of the first annular cavity away from the seawater, and the chamber pressure of the second annular cavity varies according to the ship's draft.

[0015] The third annular cavity is installed on the side of the second annular cavity away from the first annular cavity, and the chamber pressure of the third annular cavity is always maintained 0.02-0.03 bar higher than that outside the chamber.

[0016] A fourth annular cavity, wherein the fourth annular cavity is installed on the side of the third annular cavity away from the second annular cavity;

[0017] The fifth annular cavity, and multiple fifth annular cavities are installed at the other end of the shaft tube body. The fourth and fifth annular cavities are used for the rotational lubrication of the ship's stern shaft.

[0018] Preferably, the third annular cavity pipe is connected to an inlet pressure sensor, which is used to detect the inlet air pressure value. The fourth annular cavity is connected to a tailpipe oil tank through a pipe, which is used for lubrication control between the shaft tube body and the fourth annular cavity.

[0019] Preferably, the air control unit includes:

[0020] An air inlet, wherein the air inlet is used for air intake;

[0021] An oil separator, which is installed at one end of the air inlet, is used to remove oil impurities from the air.

[0022] An air filter is installed on one side of the oil separator and is used to further filter the gas from which oil impurities have been removed.

[0023] An air pressure control switch is connected to the air outlet of the air filter and is used to control the air pressure entering the inner cavity of the third annular cavity.

[0024] An air intake pipe is installed at the air outlet of an air pressure control switch via multiple valve bodies.

[0025] A backflushing port is installed between the air inlet pipe and the air pressure control switch via a pipe. The backflushing port is used for backflushing the inner cavity of the air filter and the oil separator.

[0026] Preferably, the discharge collection unit includes:

[0027] A discharge tank is connected to the pump body via a pipe, and the inlet end of the pump body is installed at the bottom of the inner cavity of the third annular cavity via a pipe.

[0028] A high-level liquid alarm sensor, wherein multiple high-level liquid alarm sensors are installed in the inner cavity of the discharge tank;

[0029] A collection box, which is fixed to the inner wall of the discharge box;

[0030] The inlet pipes, a plurality of which are fixed in a longitudinal structure to one end of the outlet pipe of the pump body via regulating valves, are fixedly inserted into one side of the collection tank;

[0031] The inner cavity of the collection box is divided into multiple partitioned cavities by a partition plate. The partitioned cavities are used to hold seawater, oil-water mixture and oil, respectively.

[0032] An auxiliary component is installed inside the partition cavity and is used to assist in high-level liquid sensing.

[0033] An overflow assembly is installed on one side of an auxiliary assembly and is used to assist in the overflow of liquid.

[0034] Preferably, the auxiliary component includes:

[0035] A fixing box is fixed to the top of the inner cavity of the partition chamber, and one end of the fixing box is fixedly inserted and connected to the outer wall of the discharge box;

[0036] A water pipe, which is fixed to the bottom of the other end of the fixing box;

[0037] A float ball, wherein the float ball is disposed in the inner cavity of the water pipe;

[0038] An infrared sensor is fixedly inserted into the bottom of the fixing box. The infrared sensor is used for infrared detection of the float ball at the top of the water pipe cavity.

[0039] Preferably, the overflow assembly includes:

[0040] A push cylinder is installed in the inner cavity of the fixed box, and the infrared sensor is connected to the push cylinder through an external controller;

[0041] A rotating rod is inserted into the bottom of a fixed box via a pin, and a push cylinder is used to push the top of the rotating rod.

[0042] A pin, which is slidably inserted into the bottom of the rotating rod;

[0043] A plug, wherein the plug is fixed to one end of the pin;

[0044] An overflow tube is fixedly inserted into the top of the inner cavity of the partition chamber, and the plug is used to seal the flared end of the overflow tube.

[0045] A pull rope is fixed to the top of the rotating rod, and the pull rope is slidably inserted into one end of the fixed box;

[0046] A compression spring is installed between the rotating rod and the inner wall of the fixed box, and the compression spring is used for the elastic recovery of the rotating rod.

[0047] Preferably, the lubricating oil control unit includes:

[0048] A cooler, which is connected to the outside of the shaft body of the shaft tube body via a pipe, is used for cooling lubricating oil;

[0049] An exhaust control valve is installed at the discharge end of the cooler and is connected to the tailpipe oil tank via a valved pipe.

[0050] Preferably, the front-mounted fuel tank mechanism includes:

[0051] A sealed oil tank, which is connected to the inner cavity of the fifth annular cavity via a valved pipe;

[0052] A vent is installed on the top of the sealed oil tank, and level sensors are installed in the inner cavities of both the sealed oil tank and the tailpipe oil tank.

[0053] A control method for an air sealing system of a ship's stern shaft sealing device includes the following steps:

[0054] Step 1: When using an external pressure sensor to detect the ship's draft pressure, the air pressure in the second annular cavity follows the pressure in the first annular cavity and is controlled to remain 0.01-0.02 MPa lower than the ship's draft. The air pressure in the third annular cavity is 0.02-0.03 bar higher than the external pressure. The pressure in the fourth annular cavity follows the pressure in the third annular cavity and is 0.03-0.05 MPa higher than the pressure in the third annular cavity.

[0055] Step 2: When the external pressure sensor malfunctions in detecting the ship's draft pressure, the air control unit directly controls the air chamber precisely. When the ship's draft changes during navigation, the air chamber pressure will automatically adjust. The air chamber pressure inside the third ring cavity will always be 0.02-0.03 bar higher than the external pressure. Excess pressure will release air bubbles to the outside of the hull through the gaps in the sealing ring.

[0056] The technical effects and advantages of this invention are as follows:

[0057] (1) The present invention uses a combination of sealing and control mechanisms to adjust the pressure of each chamber in a stepwise and dynamic manner according to the ship's draft and operating conditions, thereby constructing a reliable pressure gradient barrier that effectively prevents seawater intrusion and lubricating oil leakage. Furthermore, by precisely controlling the air pressure to an extremely high level of 0.001 bar, the system enables the sealing ring and the journal to form a non-contact or micro-contact state, which fundamentally reduces mechanical friction and wear and extends the service life of the sealing ring.

[0058] (2) By setting different annular cavities on the sealing mechanism, the present invention enables the system to detect changes in the ship's draft and adjust the pressure of the corresponding annular cavity in real time, thereby achieving self-adaptation to the navigation conditions. Even when the external pressure sensor fails, the backup control mechanism can still ensure the stability of the pressure in the third annular cavity and ensure the continuous safe operation of the system.

[0059] (3) This invention integrates three major units—air control, lubricating oil control, and leakage collection—through a combination of an air control unit, a leakage collection unit, and a lubricating oil control unit. All units are managed by a central controller, achieving full automation of the entire process of air pressure regulation, oil cooling, leakage monitoring, and collection. This improves the system's sealing reliability and operational efficiency. Furthermore, the leakage collection unit not only has an oil-water analyzer for real-time identification and classification of liquid components but also features a multi-level alarm and emergency discharge mechanism consisting of a high-level liquid alarm sensor, auxiliary components, and an overflow component, greatly enhancing the safety of leakage handling. Attached Figure Description

[0060] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0061] Figure 1 This is a schematic diagram of the system framework structure of the present invention;

[0062] Figure 2 This is a schematic diagram of the system air control unit structure of the present invention;

[0063] Figure 3 This is a schematic diagram of the system lubricating oil control unit of the present invention;

[0064] Figure 4 This is a schematic diagram of the system sealing oil tank structure of the present invention;

[0065] Figure 5 This is a schematic diagram of the shaft tube body structure of the present invention;

[0066] Figure 6 This is a schematic diagram of the overall structure of the control frame of the present invention;

[0067] Figure 7 This is a schematic diagram of the front structure of the control frame of the present invention;

[0068] Figure 8 This is a schematic diagram of the front structure of the discharge box of the present invention;

[0069] Figure 9 For the present invention Figure 8 Enlarged structural diagram at point A in the middle.

[0070] In the attached image:

[0071] 100. Shaft tube body; 200. Sealing structure; 201. First annular cavity; 202. Second annular cavity; 203. Third annular cavity; 204. Fourth annular cavity; 205. Fifth annular cavity; 300. Inlet pressure sensor; 400. Control mechanism; 401. Control frame; 402. Air control unit; 421. Air inlet; 422. Oil separator; 423. Air filter; 424. Air pressure control switch; 425. Inlet pipe; 426. Backwash port; 403. Discharge and collection unit; 431. Discharge tank; 432. High liquid level alarm sensor; 433. Collection tank; 434. Liquid inlet. Pipe; 435, partition chamber; 436, auxiliary components; 4601, fixing box; 4602, water pipe; 4603, float; 4604, infrared sensor; 437, overflow assembly; 4701, push cylinder; 4702, rotating rod; 4703, pin; 4704, plug; 4705, overflow pipe; 4706, pull rope; 4707, compression spring; 404, lubricating oil control unit; 441, cooler; 442, discharge control valve; 405, pump body; 406, controller; 500, front oil tank mechanism; 501, sealed oil tank; 502, vent; 600, tailpipe oil tank. Detailed Implementation

[0072] 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.

[0073] This invention provides, for example Figures 1-9 The image shows an air sealing system for a ship's stern shaft sealing device.

[0074] Example 1: Includes a shaft tube body 100, with a sealing structure 200 installed at one end. An inlet pressure sensor 300 is installed at the air inlet end of the sealing structure 200. The sealing structure 200 includes a first annular cavity 201, a second annular cavity 202, a third annular cavity 203, a fourth annular cavity 204, and a fifth annular cavity 205. The first annular cavity 201 is installed at the end of the shaft tube body 100 closest to seawater, and its inner cavity is in direct contact with seawater. The second annular cavity 202 is installed on the side of the first annular cavity 201 furthest from seawater, separated from seawater by a sealing strip. The chamber pressure of the second annular cavity 202 varies according to the ship's draft. The third annular cavity 203 is installed on the side of the second annular cavity 202 furthest from the first annular cavity 201. On one side, the chamber pressure of the third annular cavity 203 is always maintained 0.02-0.03 bar higher than that outside the chamber. The fourth annular cavity 204 is installed on the side of the third annular cavity 203 away from the second annular cavity 202. Multiple fifth annular cavities 205 are installed at the other end of the shaft tube body 100. The fourth annular cavity 204 and the fifth annular cavity 205 are used for the rotational lubrication of the ship's stern shaft. The pipe of the third annular cavity 203 is connected to the inlet pressure sensor 300. The inlet pressure sensor 300 is used to detect the inlet air pressure value. By using precise control of the air pressure, the sealing ring on the sealing structure 200 is not completely pressed against the shaft, reducing the wear of the sealing ring and extending the service life of the sealing ring. By precisely controlling the air pressure to 0.001 bar, the service life of the sealing ring is effectively extended.

[0075] The inlet pressure sensor 300 is connected to a control mechanism 400 via a pipeline. A front-mounted oil tank mechanism 500 is installed at the tail end of the shaft tube body 100. The control mechanism 400 includes a control frame 401, an air control unit 402, a discharge collection unit 403, a lubricating oil control unit 404, a pump body 405, and a main controller 406. The control frame 401 is a frame box structure installed inside the ship's hold. The air control unit 402 is installed on top of the control frame 401 and is used to connect to the inlet pressure sensor 300 to control the air pressure in the annular cavity of the sealing structure 200, facilitating the control of the second annular cavity. Precise control of the internal air pressure of 202; the discharge collection unit 403 is installed at the bottom corner of the control frame 401; the discharge collection unit 403 is used for the classified collection of leaked liquid on the sealing structure 200, so that oil, seawater and oil-water mixture can be classified and collected, which facilitates the recycling of oil and reduces the need for subsequent oil separation treatment; the lubricating oil control unit 404 is installed in the middle of the control frame 401; the lubricating oil control unit 404 is used for the cooling control of the lubricating oil of the shaft tube body 100; the pump body 405 is connected to the discharge collection unit 403; the main controller 406 is installed at the bottom of the control frame 401; the main controller 406 is used for the overall control of the system.

[0076] Specifically, the air control unit 402 includes an air inlet 421, an oil separator 422, an air filter 423, an air pressure control switch 424, an intake pipe 425, and a backflushing port 426. The air inlet 421 is used for air intake. The oil separator 422 is installed at one end of the air inlet 421 and is used to remove oil impurities from the air. The air filter 423 is installed on one side of the oil separator and is used to further filter the air after removing oil impurities. The air pressure control switch 424 is connected to the outlet of the air filter 423 and is used to control the air pressure entering the third annular cavity 203. The intake pipe 425 is installed at the air pressure control switch via multiple valve bodies. At the outlet of 424, the backwash port 426 is installed between the air inlet pipe 425 and the air pressure control switch 424 via a pipe. The backwash port 426 is used for backwashing the inner cavity of the air filter 423 and the oil separator 422. Through the oil separator 422 and the air filter 423, oil mist, impurities, etc. in the air are easily filtered, so that the gas entering the inner cavity of the third ring cavity 203 is clean. This facilitates the improvement of the accuracy of the air pressure control switch 424 in controlling the air pressure. Furthermore, the backwash port 426 facilitates the cleaning of the air filter 423 and the oil separator 422, enabling them to be cleaned in reverse on a regular basis. This effectively prevents clogging, maintains high filtration efficiency, and extends the maintenance cycle and service life of key components.

[0077] More specifically, the discharge and collection unit 403 includes a discharge tank 431, a high-liquid-level alarm sensor 432, a collection tank 433, an inlet pipe 434, a partition chamber 435, auxiliary components 436, and an overflow component 437. The discharge tank 431 is connected to the pump body 405 via a pipe. The inlet end of the pump body 405 is installed at the bottom of the inner cavity of the third annular cavity 203 via a pipe. An oil-water analyzer is installed on the inlet pipe between the pump body 405 and the discharge tank 431 for detecting the liquid leaking from the third annular cavity 203. Multiple high-liquid-level alarm sensors... Sensor 432 is installed inside the discharge tank 431. Collection tank 433 is fixed to the inner wall of discharge tank 431. Multiple inlet pipes 434 are fixed longitudinally to one end of the outlet pipe of pump body 405 via regulating valves. The inlet pipes 434 are fixedly inserted into one side of collection tank 433. The inner cavity of collection tank 433 is divided into multiple partitioned chambers 435 by a partition plate. The partitioned chambers 435 are used to hold seawater, oil-water mixture, and oil, respectively, facilitating direct contact between the oil-water analyzer of pump body 405 and discharge tank 431 when oil or water is detected. Liquid enters either the oil chamber or the water chamber through two valved inlet pipes 434. When a change in water and oil is detected, liquid is injected into the oil-water mixing chamber through another valved inlet pipe 434. Multiple partitioned chambers 435 have outlet pipes with on / off valves at their bottoms for liquid discharge. Multiple high-level liquid alarm sensors 432 are installed inside the partitioned chambers 435 to detect high liquid levels in different chambers and are configured for remote audible and visual alarms. If an excessively high liquid level is detected, an audible and visual alarm will be triggered. The system enables staff to discharge liquid via a switch valve. An auxiliary component 436 is installed inside the partition chamber 435 to assist in high-level liquid sensing. An overflow component 437 is installed on one side of the auxiliary component 436 to assist in liquid overflow. The discharge collection unit 403, through the design of the partition chamber 435, realizes the automatic classification, collection, and storage of seawater, oil, and oil-water mixtures. This not only facilitates the recycling and reuse of waste oil but also significantly reduces the subsequent oil-water separation processing costs and environmental pressure.

[0078] Furthermore, the auxiliary component 436 includes a fixing box 4601, a water pipe 4602, a float 4603, and an infrared sensor 4604. The fixing box 4601 is fixed to the top of the inner cavity of the partition chamber 435. One end of the fixing box 4601 is fixedly inserted into the outer wall of the discharge tank 431. The inner cavity of the fixing box 4601 communicates with the external space of the discharge tank 431 to facilitate stable gas discharge. The water pipe 4602 is fixed to the bottom of the other end of the fixing box 4601. The float 4603 is disposed in the inner cavity of the water pipe 4602. The infrared sensor 4604 is fixedly inserted into the bottom of the fixing box 4601. The infrared sensor 4604 is used for... Infrared detection of the float 4603 at the top of the inner cavity of the water pipe 4602 allows the liquid to rise into the inner cavity of the water pipe 4602 through the rising of the liquid in the adjacent partition cavity 435, causing the float 4603 to float and rise. This makes it easy for the infrared sensor 4604 to sense the position of the float 4603, facilitating the overflow component 437 to drain the liquid. The auxiliary component 436 can also assist the high-level liquid alarm sensor 432 in high-level drainage. Even if the high-level liquid alarm sensor 432 is damaged or personnel cannot reach the site, drainage can still be carried out to prevent leakage and accumulation at the end of the shaft tube body 100, which would affect the service life of the sealing ring.

[0079] Furthermore, the overflow assembly 437 includes a push cylinder 4701, a rotating rod 4702, a pin 4703, a plug 4704, an overflow pipe 4705, a pull rope 4706, and a compression spring 4707. The push cylinder 4701 is installed inside the fixed box 4601. An infrared sensor 4604 is connected to the push cylinder 4701 via an external controller, allowing the controller to drive the push cylinder 4701 when the liquid rises to its highest position. The rotating rod 4702 is inserted into the bottom of the fixed box 4601 via a pin. 1. A pin 4703 is slidably inserted into the bottom of the rotating rod 4702, and a plug 4704 is fixed to one end of the pin 4703. The plug 4704 is made of sealing rubber. An overflow tube 4705 is fixedly inserted into the top of the inner cavity of the partition chamber 435. The plug 4704 is used to seal the flared end of the overflow tube 4705. A pull rope 4706 is fixed to the top of the rotating rod 4702. The pull rope 4706 is slidably inserted into one end of the fixing box 4601. A compression spring 4707 is installed between the rotating rod 4702 and the fixing box 4601. Between the inner walls, a compression spring 4707 is used for the elastic recovery of the rotating rod 4702. An arc-shaped rod is fitted inside the compression spring 4707, and this arc-shaped rod is slidably inserted into the top of the rotating rod 4702. Both ends of the arc-shaped rod are fixed to the inner wall of the fixing box 4601. Due to the elasticity of the compression spring 4707, when the float 4603 rises to the sensing position of the infrared sensor 4604, the infrared sensor 4604 transmits a sensing signal to the controller. The controller then controls the push cylinder 4701 to push the top of the rotating rod 4702, causing the compression spring 4707 to compress. The pin 4703 moves the plug 4704 a distance away from the inner cavity of the overflow pipe 4705, but not completely away from the flared opening of the overflow pipe 4705, allowing the liquid to be discharged through the overflow pipe 4705. When the float 4603 has not floated to the sensing area of ​​the infrared sensor 4604, the cylinder 4701 is pushed back, and the rotating rod 4702 is no longer pushed. The compression spring 4707 drives the rotating rod 4702 to return to its original position, so that the plug 4704 seals the inner cavity of the overflow pipe 4705 along the flared opening, ensuring the stability of the liquid in the inner cavity of the partition chamber 435.

[0080] Meanwhile, the lubricating oil control unit 404 includes a cooler 441 and a discharge control valve 442. The cooler 441 is connected to the outside of the shaft of the shaft tube body 100 through a pipe. The cooler 441 is used to cool the lubricating oil. The discharge control valve 442 is installed at the discharge end of the cooler 441, that is, the liquid inlet end of the cooler 441 is installed between the fourth annular cavity 204 and the fifth annular cavity 205, so that the liquid in the inner cavity of the fourth annular cavity 204 and the fifth annular cavity 205 can enter the inner cavity of the cooler 441 through the circulation pipe for cooling, and then be discharged under control. A normally closed valve is installed at the bottom of the inner cavity of the fourth annular cavity 204 through a pipe. A normally closed valve is installed between the pipe of the third annular cavity 203 and the pump body 405 for maintenance of the pipe. The lubricating oil control unit 404 performs forced circulation cooling of the lubricating oil through the cooler 441 to ensure good heat dissipation of the lubrication parts, good oil flow, and at the same time maintains the stability of the lubricating oil cavity pressure, which is conducive to the durability of the sealing effect.

[0081] In addition, the front oil tank mechanism 500 includes a sealed oil tank 501 and a vent 502. The sealed oil tank 501 is connected to the inner cavity of the fifth annular cavity 205 through a valved pipe. The vent 502 is installed on the top of the sealed oil tank 501 and is used for ventilation of the inner cavity of the sealed oil tank 501. The sealed oil tank 501 is externally connected to a normally closed valve for treating waste oil in the inner cavity of the sealed oil tank 501.

[0082] Example 2: Based on Example 1, the fourth annular cavity 204 is connected to the tailpipe oil tank 600 via a pipeline. The tailpipe oil tank 600 is used for lubrication control between the shaft tube body 100 and the fourth annular cavity 204. The discharge control valve 442 is connected to the tailpipe oil tank 600 via a valve-equipped pipeline. Liquid level sensors are installed in the inner cavities of both the sealing oil tank 501 and the tailpipe oil tank 600. The lubricating oil on the shaft tube body 100 enters the lubricating oil control unit 404 through the pipeline, and then enters the inner cavity of the tailpipe oil tank 600. It then enters the inner cavity of the fourth annular cavity 204 through a circulation pump for forced lubrication, ensuring that the lubricating oil remains circulating and has good fluidity. At the same time, the pressure of the lubricating oil cavity is also precisely controlled, resulting in good heat dissipation.

[0083] A control method for an air sealing system of a ship's stern shaft sealing device includes the following steps:

[0084] Step 1: When using an external pressure sensor to detect the ship's draft pressure, the air pressure inside the second annular cavity 202 changes in accordance with the pressure inside the first annular cavity 201, always remaining 0.01-0.02 MPa lower than the ship's draft. The air pressure inside the third annular cavity 203 is 0.02-0.03 bar higher than the external pressure. The pressure inside the fourth annular cavity 204 changes in accordance with the air pressure inside the third annular cavity 203, and the pressure inside the fourth annular cavity 204 is 0.03-0.05 MPa higher than the pressure inside the third annular cavity 203.

[0085] Step 2: When the external pressure sensor malfunctions in detecting the ship's draft pressure, the air control unit 402 is used to precisely control the air chamber. When the ship's draft changes during navigation, the air chamber pressure will automatically adjust. The air chamber pressure inside the third ring chamber 203 will always be 0.02-0.03 bar higher than that outside the ship. Excess pressure will release air bubbles to the outside of the ship through the gap in the sealing ring.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An air sealing system for a ship's stern shaft sealing device, comprising a shaft tube body (100), characterized in that: A sealing structure (200) is installed at the end of the shaft tube body (100), an inlet pressure sensor (300) is installed at the air inlet end of the sealing structure (200), a control mechanism (400) is installed on the inlet pressure sensor (300) through a pipe, and a front oil tank mechanism (500) is installed at the tail end of the shaft tube body (100). The control mechanism (400) includes: Control frame (401), wherein the control frame (401) is a frame box structure; An air control unit (402) is mounted on the top of the control frame (401) and is used to connect with the inlet pressure sensor (300) to control the air pressure in the annular cavity of the sealing structure (200). A discharge collection unit (403) is installed at the corner of the bottom of the control frame (401). The discharge collection unit (403) is used for the classified collection of leaked liquid on the sealing structure (200). The lubricating oil control unit (404) is installed in the middle of the control frame (401) and is used for cooling control of the lubricating oil of the shaft tube body (100). Pump body (405), which is connected to discharge collection unit (403); A master controller (406) is mounted on the bottom of the control frame (401) and is used for the overall control of the system.

2. The air sealing system for a ship stern shaft sealing device according to claim 1, characterized in that: The sealing structure (200) includes: The first annular cavity (201) is installed at the end of the shaft tube body (100) near the seawater; The second annular cavity (202) is installed on the side of the first annular cavity (201) away from the seawater, and the chamber pressure of the second annular cavity (202) varies according to the ship's draft; The third annular cavity (203) is installed on the side of the second annular cavity (202) away from the first annular cavity (201), and the chamber pressure of the third annular cavity (203) is always kept 0.02-0.03 bar higher than that outside the chamber. The fourth annular cavity (204) is installed on the side of the third annular cavity (203) away from the second annular cavity (202); The fifth annular cavity (205), a plurality of the fifth annular cavities (205) are installed at the other end of the shaft tube body (100), and the fourth annular cavity (204) and the fifth annular cavity (205) are used for rotational lubrication of the ship's stern shaft.

3. An air sealing system for a ship stern shaft sealing device according to claim 2, characterized in that: The third annular cavity (203) is connected to the inlet pressure sensor (300), which is used to detect the inlet air pressure value. The fourth annular cavity (204) is connected to the tailpipe oil tank (600) through a pipe. The tailpipe oil tank (600) is used for lubrication control between the shaft tube body (100) and the fourth annular cavity (204).

4. An air sealing system for a ship stern shaft sealing device according to claim 2, characterized in that: The air control unit (402) includes: An air inlet (421) is provided for air intake; An oil separator (422) is installed at one end of an air inlet (421) and is used to remove oil impurities from the air. An air filter (423) is installed on one side of the oil separator (422) and is used to further filter the gas that has been degreased of oil impurities. An air pressure control switch (424) is connected to the outlet of an air filter (423). The air pressure control switch (424) is used to control the air pressure entering the inner cavity of the third annular cavity (203). An air intake pipe (425) is installed at the outlet of an air pressure control switch (424) via multiple valve bodies; A backflushing port (426) is installed between the air intake pipe (425) and the air pressure control switch (424) via a pipe. The backflushing port (426) is used for backflushing the inner cavity of the air filter (423) and the oil separator (422).

5. An air sealing system for a ship stern shaft sealing device according to claim 1, characterized in that: The discharge collection unit (403) includes: The discharge tank (431) is connected to the pump body (405) through a pipe, and the inlet end of the pump body (405) is installed at the bottom of the inner cavity of the third annular cavity (203) through a pipe; Liquid high level alarm sensor (432), a plurality of said liquid high level alarm sensors (432) are installed in the inner cavity of the discharge tank (431); A collection box (433) is fixed to the inner wall of the discharge box (431); The inlet pipe (434) and multiple inlet pipes (434) are respectively fixed to one end of the outlet pipe of the pump body (405) in a longitudinal structure through the regulating valve. The inlet pipe (434) is fixedly inserted into one side of the collection box (433). The inner cavity of the collection box (433) is divided into multiple inner cavities (435) by a partition, and the inner cavities (435) are respectively used to load seawater, oil-water mixture and oil; An auxiliary component (436) is installed in the inner cavity of the partition cavity (435) and is used to assist in high-level liquid sensing. An overflow assembly (437) is installed on one side of an auxiliary assembly (436) and is used to assist in the overflow of liquid.

6. An air sealing system for a ship stern shaft sealing device according to claim 5, characterized in that: The auxiliary component (436) includes: A fixing box (4601) is fixed to the top of the inner cavity of the partition cavity (435), and one end of the fixing box (4601) is fixedly inserted and connected to the outer wall of the discharge box (431). A water pipe (4602) is fixed to the bottom of the other end of the fixing box (4601); A float (4603) is disposed in the inner cavity of the water pipe (4602); An infrared sensor (4604) is fixedly inserted into the bottom of the fixing box (4601). The infrared sensor (4604) is used to detect the infrared of the float (4603) at the top of the inner cavity of the water pipe (4602).

7. An air sealing system for a ship stern shaft sealing device according to claim 6, characterized in that: The overflow assembly (437) includes: A push cylinder (4701) is installed in the inner cavity of a fixed box (4601), and an infrared sensor (4604) is connected to the push cylinder (4701) via an external controller; A rotating rod (4702) is inserted into the bottom of a fixed box (4601) via a pin. The pushing cylinder (4701) is used to push the top of the rotating rod (4702). A pin (4703) is slidably inserted into the bottom of a rotating rod (4702); A plug (4704) is fixed to one end of a pin (4703); An overflow tube (4705) is fixedly inserted into the top of the inner cavity of the partition cavity (435), and a plug (4704) is used to seal the flared end of the overflow tube (4705). A pull rope (4706) is fixed to the top of the rotating rod (4702), and the pull rope (4706) is slidably inserted into one end of the fixed box (4601); A compression spring (4707) is installed between the rotating rod (4702) and the inner wall of the fixed box (4601), and the compression spring (4707) is used for the elastic recovery of the rotating rod (4702).

8. An air sealing system for a ship stern shaft sealing device according to claim 3, characterized in that: The lubricating oil control unit (404) includes: Cooler (441), the cooler (441) is connected to the outside of the shaft of the shaft tube body (100) through a pipe, the cooler (441) is used for cooling the lubricating oil; The discharge control valve (442) is installed at the discharge end of the cooler (441) and is connected to the tailpipe oil tank (600) through a valved pipe.

9. An air sealing system for a ship stern shaft sealing device according to claim 3, characterized in that: The front-mounted fuel tank mechanism (500) includes: A sealed oil tank (501) is connected to the inner cavity of the fifth annular cavity (205) via a valved pipe; A vent (502) is installed on the top of the sealed oil tank (501). Liquid level sensors are installed in the inner cavities of both the sealed oil tank (501) and the tailpipe oil tank (600).

10. The control method for an air sealing system for a ship's stern shaft sealing device according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: When using the external pressure sensor to detect the ship's draft pressure, the air pressure in the second annular cavity (202) changes according to the pressure in the first annular cavity (201), and is always kept 0.01-0.02 MPa lower than the ship's draft. The air pressure in the third annular cavity (203) is 0.02-0.03 bar higher than the external pressure. The pressure in the fourth annular cavity (204) changes according to the air pressure in the third annular cavity (203), and the pressure in the fourth annular cavity (204) is 0.03-0.05 MPa higher than the pressure in the third annular cavity (203). Step 2: When the pressure sensor outside the cabin malfunctions in detecting the ship's draft pressure, the air control unit (402) is used to precisely control the air chamber. When the ship's draft changes during sailing, the air chamber pressure will automatically adjust. The air chamber pressure inside the third ring chamber (203) will always be 0.02-0.03 bar higher than that outside the cabin. Excess pressure will release bubbles to the outside of the cabin through the gap of the sealing ring.

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