An airbag type mechanical seal structure and its sealing method

Abstract

The present invention relates to an airbag-type mechanical seal structure and its sealing method in the technical field of LNG ships, including: an annular airbag sealing ring, the floor bulkhead of the gas supply system chamber, and the drooping wall at the top of the liquid tank. Flexible sealing lips in a ring shape are fixedly arranged at both the top and the bottom of the annular airbag sealing ring, and hard sealing rings are fixedly arranged at both the bottom of the floor bulkhead of the gas supply system chamber and the top of the drooping wall at the top of the liquid tank. The hard sealing ring and the flexible sealing lip are connected in a fitting manner. The present invention can fully seal the moving gap formed between the top of the liquid tank and the gas supply system, meet the technical requirements of relative deformation and movement between the deformation of the top of the liquid tank and the surrounding hull deck components under conditions such as ship navigation, severe sea conditions, and temperature differences, and also meet the sealing technical requirements between the top of the liquid tank and the gas supply system chamber, avoid the risk of ultra-low temperature gas leakage, and achieve the closed-loop management of "monitoring - analysis - compensation - alarm", improving the system safety and maintenance efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG ships, and particularly to an airbag type mechanical seal structure and a sealing method thereof. Background Art

[0002] A liquefied natural gas ship, abbreviated as "LNG ship", refers to a "ship" specially designed to transport liquefied natural gas. Its liquid tanks are usually arranged inside the hull below the main deck of the ship. The liquid tank is an independent self - contained tank. After the liquid tank is placed under the deck, the top of the liquid tank is a gas chamber with a part not filled with liquid. A drooping wall covers the gas chamber, and the annular fence of the drooping wall extends beyond the edge of the gas chamber; the top of the liquid tank needs to pass through the ship's deck and enter the indoor gas supply system for LNG storage conversion transition and gas preparation. An active clearance space is formed between the top of the liquid tank and the floor fence of the gas supply system room. This space is generally called the cargo void area. The cargo void area provides a buffer space for the displacement and thermal expansion and contraction of the liquid tank. At the same time, in order to isolate the ultra - low temperature dangerous gas source, the cargo void area is always in a sealed, dry or inert state, and the gas supply system is used to supplement gas to the cargo void area to keep the cargo void area in a slightly positive pressure state. Therefore, this active clearance needs to be sealed and isolated from other spaces of the ship's deck structure to prevent the safety risk brought by the leakage of ultra - low temperature gas. This active clearance is the only place in the entire sealed space where ultra - low temperature gas may leak.

[0003] At present, during the transportation of LNG ships, it is crucial to seal the active clearance formed between the top of the liquid tank and the gas supply system. Traditional sealing structures mostly use rigid structures or welding methods for connection and sealing. However, when the LNG liquid tank is loaded with ultra - low temperature LNG liquid, it will produce certain thermal expansion and contraction deformation, and the liquid sloshing will also cause relative movement between the liquid tank and the main hull, resulting in a decline in sealing performance and a leakage risk. Moreover, there is a lack of an effective wear compensation mechanism, which cannot meet the requirements of high reliability and long life of the sealing structure for LNG ships. Therefore, it is urgent to design a capsule - type sealing device and a sealing connection method for the top of the liquid tank to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a capsule - type sealing device and a sealing connection method for the top of the liquid tank to solve the problems raised in the above background art.

[0005] To solve the above problems, the present invention provides an airbag type mechanical seal structure, including:

[0006] An annular airbag sealing ring, the floor enclosure of the air supply system chamber, and the drooping wall at the top of the liquid tank. Annular flexible sealing lips are fixedly arranged at both the top and bottom of the annular airbag sealing ring. Hard sealing rings are fixedly arranged at the bottom of the floor enclosure of the air supply system chamber and the top of the drooping wall at the top of the liquid tank. The hard sealing ring and the flexible sealing lip are connected in a fitting manner. Annular U-shaped pressing plates are fixedly arranged on both the inner walls of the top and bottom of the annular airbag sealing ring. Annular backing plates are fixedly arranged at the top of the floor enclosure of the air supply system chamber and the bottom of the drooping wall at the top of the liquid tank. Fixed components are arranged at equal distances between the annular backing plate and the annular U-shaped pressing plate;

[0007] A wear compensation mechanism is installed between the two annular U-shaped pressing plates and is located inside the annular airbag sealing ring. An inflation component for driving the annular airbag sealing ring and the wear compensation mechanism to work is arranged outside the annular airbag sealing ring.

[0008] The present invention is further configured such that an annular wedge groove is provided at the bottom near the middle of the hard sealing ring, and an annular wedge block that fits in the annular wedge groove is fixed to the top of the flexible sealing lip. Both the flexible sealing lip and the annular wedge block are made of a composite of silicone rubber and carbon fiber.

[0009] The present invention is further configured such that the fixed component includes a bolt, a nut, and an anti-slip gasket. The bolt is fixed to the top of the annular U-shaped pressing plate and extends outside the annular airbag sealing ring. Through holes for the bolt to pass through at equal distances are provided on the flexible sealing lip, the hard sealing ring, the floor enclosure of the air supply system chamber, the drooping wall at the top of the liquid tank, and the annular backing plate. The bolt is in threaded cooperation with the nut to press the anti-slip gasket against the annular backing plate.

[0010] The present invention is further configured such that the annular airbag sealing ring is arranged at the movable gap between the floor enclosure of the air supply system chamber and the drooping wall at the top of the liquid tank. The longitudinal section of the annular airbag sealing ring is an M-curve-shaped telescopic structure. Inner convex reinforcing ribs and outer convex reinforcing ribs are fixedly arranged at equal distances on the inner and outer arc surfaces of the bag-shaped structure of the annular airbag sealing ring.

[0011] The present invention is further configured such that the annular airbag sealing ring is composed of a cryogenic weather-resistant elastic layer, a reinforcing fiber support layer, and an anti-wear protection layer. The cryogenic weather-resistant elastic layer is made of a composite material of polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer. The reinforcing fiber support layer is woven from aramid fibers. The anti-wear protection layer is made of polyurethane material.

[0012] The present invention is further configured such that a grid maze contact surface is provided on the top surface of the flexible sealing lip.

[0013] The present invention is further configured such that a wear-resistant coating is provided on the bottom surface of the hard sealing ring.

[0014] The present invention is further configured such that the wear compensation mechanism includes a mounting frame fixedly installed on the two annular U-shaped pressing plates, and fixed air cylinders are fixedly arranged on the two mounting frames in an equidistant and annular distribution. The inner walls of the fixed air cylinders are all inserted with jacking columns, and reset springs are fixed between the bottom ends of the jacking columns and the inner walls of the fixed air cylinders. The top ends of the jacking columns are fixed with the same annular jacking rod. An annular groove is arranged on the surface of the jacking column, and a piston sleeve is installed on the inner wall of the annular groove. The piston sleeve is attached to the inner wall of the fixed air cylinder. Branch air pipes are fixed on the fixed air cylinders, and annular air pipes are fixed at the ends of the branch air pipes. A same metal corrugated hose is installed between the two annular air pipes. A circular sealing groove is arranged on one side of the bottom of the hard seal ring, and the position of the circular sealing groove corresponds to the position of the annular jacking rod. The annular jacking rod is used to expand a part of the annular airbag seal ring and fit it into the circular sealing groove.

[0015] The present invention is further configured such that the inflation assembly includes a second air charging pipe fixed to one side of the annular airbag seal ring and a first air charging pipe fixed to one side of the metal corrugated hose. Pressure valves are installed at one ends of the first air charging pipe and one side of the second air charging pipe. Three-way joints are installed at the air inlet ends of the two pressure valves, and an air pump is installed at one end of the three-way joint. Cavities are arranged in the annular wedge block at equidistant intervals, and pressure sensors are installed on the inner walls of the cavities. The pressure sensors are used to detect the sealing contact pressure between the annular wedge block and the annular wedge groove. An alarm is arranged on the first air charging pipe close to the pressure valve, and the pressure sensors, the air pump, the pressure valves and the alarm are electrically connected to a controller.

[0016] A sealing method for an airbag type mechanical seal structure, which is applied to an airbag type mechanical seal structure, includes the following steps:

[0017] Step 1, installation preparation: Place the annular airbag seal ring at the movable gap between the floor enclosure of the air supply system chamber and the drooping wall at the top of the liquid tank, and perform preliminary installation through the fixing assembly. At this time, the bolts sequentially pass through the through holes on the flexible sealing lip, the hard seal ring, the floor enclosure of the air supply system chamber, the drooping wall at the top of the liquid tank and the annular backing plate, put on the anti-slip gasket and then screw on the nuts, and make the annular wedge block on the flexible sealing lip fit into the annular wedge groove of the hard seal ring to form an initial sealing surface, ensuring that the annular airbag seal ring is initially fixed in position with the two side walls, and the annular U-shaped pressing plate is closely attached to the annular backing plate;

[0018] Step 2. Initial inflation and sealing: Turn on the air pump. Through the tee joint and the second inflatable tube, inflate the annular airbag seal ring. The air pressure causes the annular airbag seal ring to expand, making the annular wedge fit more tightly in the annular wedge groove. At the same time, the grid maze contact surface on the top surface of the flexible seal lip contacts the bottom surface of the hard seal ring, increasing the friction and sealing effect. When the air pressure reaches the preset initial value, close the air pressure valve on the second inflatable tube to stop inflating the annular airbag seal ring, and then tighten the nut.

[0019] Step 3. Pressure monitoring and compensation preparation: Use the pressure sensor in the annular wedge to continuously detect the sealing contact pressure between it and the annular wedge groove, and transmit the data to the controller. The controller analyzes the pressure data. If the pressure value is within the normal range, maintain the current sealing state; if the pressure value is lower than the set threshold, it indicates that there may be wear or an increase in the gap on the sealing surface, and proceed to the next step.

[0020] Step 4. Wear compensation inflation: In Step 3, the controller issues an instruction to turn on the air pump and open the air pressure valve on the first inflatable tube. The gas enters the fixed air cylinder through the branch tube, the annular tube, and the metal corrugated hose. The air pressure pushes the piston sleeve, and the lifting column drives the annular lifting rod to move upward, jacking up a part of the annular airbag seal ring, making it expand and fit into the annular seal groove at the bottom of the hard seal ring to compensate for the gap caused by wear and restore the sealing pressure.

[0021] Step 5. Continuous monitoring and dynamic adjustment: The pressure sensor continuously monitors the sealing contact pressure. The controller adjusts the working state of the air pump and the opening and closing of the air pressure valve in real time according to the pressure change to ensure that the sealing surface always maintains a good sealing effect. If the pressure value remains abnormal or exceeds the set maximum compensation times, control the alarm to work through the controller to send an alarm signal to prompt the staff to carry out maintenance and repair.

[0022] In summary, after adopting the above structure, compared with the prior art, the present invention has the following advantages:

[0023] 1. In the present invention, the flexible seal lip of the annular airbag seal ring is fitted and connected with the annular wedge groove of the hard seal ring through the annular wedge to form an initial mechanical sealing surface. Combining the high elasticity and wear resistance of the silicone rubber and carbon fiber composite material, it can adapt to slight vibrations and deformations, reduce the leakage risk, and utilize the grid maze contact surface on the top surface of the flexible seal lip to cooperate with the wear-resistant coating on the bottom surface of the hard seal ring. By increasing the contact area and frictional resistance, the sealing effect is further enhanced.

[0024] 2. In the present invention, the annular airbag seal ring adopts an M-curve type telescopic structure. After inflation, the inner and outer convex reinforcing ribs on the inner and outer arc surfaces can evenly disperse the air pressure, pushing the flexible sealing lip to closely fit the hard sealing ring, forming a dynamic sealing pressure to adapt to the clearance changes under different working conditions. Moreover, the annular airbag seal ring is composed of a polytetrafluoroethylene composite material with ultra-low temperature weather resistance elastic layer, an aramid fiber reinforcing fiber support layer, and a polyurethane anti-wear protection layer, having the characteristics of resistance to high and low temperatures, tear resistance, and wear resistance, and extending the service life.

[0025] 3. In the present invention, through the wear compensation mechanism composed of a fixed air cylinder, a jacking column, and an annular jacking rod, etc., when the pressure sensor detects that the sealing pressure is lower than the threshold value, the controller commands the air pump to inflate the fixed air cylinder through the first air supply pipe, pushing the jacking column to lift a part of the annular airbag seal ring, making it expand and embed into the annular seal groove of the hard sealing ring to compensate for the clearance caused by wear. The sealing performance can be restored without manual intervention. And the sealing contact pressure is monitored in real time through the pressure sensor. Combining the controller and the alarm, the inflation pressure can be dynamically adjusted and an early warning can be given in case of abnormality. For example, if the maximum compensation times are exceeded or the pressure remains abnormal, a closed-loop management of "monitoring - analysis - compensation - alarm" is realized, improving the system safety and maintenance efficiency.

[0026] 4. In the present invention, the annular U-shaped pressing plate and the annular backing plate are fixed by bolts, nuts, and anti-slip gaskets to ensure the firm mechanical connection between the airbag seal ring and the floor enclosure wall of the air supply system chamber and the drooping wall at the top of the liquid tank, avoiding displacement or detachment after inflation. And the adopted sealing structure can fully seal the movable clearance formed between the top of the liquid tank and the air supply system, meeting the technical requirements of relative deformation and movement between the deformation of the top of the liquid tank and the surrounding hull deck components under conditions such as ship navigation, harsh sea conditions, and temperature difference, and also meeting the sealing technical requirements between the top of the liquid tank and the air supply system chamber, avoiding the risk of ultra-low temperature gas leakage. Brief Description of the Drawings

[0027] Figure 1 is the overall cross-sectional view of an airbag type mechanical seal structure of the present invention;

[0028] Figure 2 is the schematic diagram of the pressure sensor and the outer convex reinforcing rib structure of an airbag type mechanical seal structure of the present invention;

[0029] Figure 3 is the cross-sectional view of the annular airbag seal ring of an airbag type mechanical seal structure of the present invention;

[0030] Figure 4 is the three-dimensional structure diagram of an airbag type mechanical seal structure of the present invention;

[0031] Figure 5 is the three-dimensional cross-sectional view of an airbag type mechanical seal structure of the present invention;

[0032] Figure 6 Schematic diagram of the first and second charging pipes of an airbag mechanical seal structure according to the present invention;

[0033] Figure 7 Schematic diagram of the anti-slip gasket and cavity of an airbag mechanical seal structure according to the present invention;

[0034] Figure 8 Schematic diagram of the annular wedge groove and annular seal groove of an airbag mechanical seal structure according to the present invention;

[0035] Figure 9 Three-dimensional view of the wear compensation mechanism of an airbag mechanical seal structure according to the present invention;

[0036] Figure 10 Schematic diagram of the jacking column and return spring of an airbag mechanical seal structure according to the present invention.

[0037] Explanation of the reference numerals in the figure:

[0038] 1. Annular airbag seal ring; 101. Ultra-low temperature weather-resistant elastic layer; 102. Reinforcing fiber support layer; 103. Anti-wear protection layer; 2. Floor enclosure wall of the gas supply system chamber; 3. Hanging wall at the top of the liquid tank; 4. Ring-shaped U-shaped pressing plate; 5. Fixing assembly; 501. Bolt; 502. Nut; 503. Anti-slip gasket; 504. Through hole; 6. Flexible seal lip; 7. Hard seal ring; 8. Annular backing plate; 9. Annular wedge block; 10. Wear compensation mechanism; 1001. Mounting frame; 1002. Fixed air cylinder; 1003. Annular air pipe; 1004. Annular jacking rod; 1005. Metal corrugated hose; 1006. Annular seal groove; 1007. Branch air pipe; 1008. Jacking column; 1009. Return spring; 1010. Piston sleeve; 11. Inflation assembly; 1101. Air pump; 1102. Three-way joint; 1103. Pressure valve; 1104. First charging pipe; 1105. Second charging pipe; 12. Pressure sensor; 13. Outer convex reinforcing rib; 14. Inner convex reinforcing rib; 15. Cavity; 16. Annular wedge groove; 17. Mesh labyrinth contact surface; 18. Wear-resistant coating. Detailed implementation manners

[0039] The following details the embodiments of the present application. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application.

[0040] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0041] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled", "set" should be understood in a broad sense. For example, it can be fixedly connected and set, or detachably connected and set, or integrally connected and set. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0042] Please refer to Figures 1 - 10 , the present invention provides a pneumatic mechanical seal structure, comprising:

[0043] The annular airbag seal ring 1, the floor bulkhead of the air supply system room 2, and the drooping wall at the top of the liquid tank 3. Ring-shaped flexible sealing lips 6 are fixedly arranged at both the top and bottom of the annular airbag seal ring 1. Hard sealing rings 7 are fixedly arranged at both the bottom of the floor bulkhead of the air supply system room 2 and the top of the drooping wall at the top of the liquid tank 3. The hard sealing ring 7 and the flexible sealing lip 6 are connected in a fitting manner. At the bottom near the middle of the hard sealing ring 7, an annular wedge groove 16 is provided. And an annular wedge block 9 that fits in the annular wedge groove 16 is fixed to the top of the flexible sealing lip 6. Both the flexible sealing lip 6 and the annular wedge block 9 are made of a composite of silicone rubber and carbon fiber. When inflated, the annular wedge block 9 can closely fit in the annular wedge groove 16 to form a sealing surface. A grid maze contact surface 17 is provided on the top surface of the flexible sealing lip 6 to increase the friction force and sealing effect of the sealing contact surface. A wear-resistant coating 18 is provided on the bottom surface of the hard sealing ring 7 to improve the wear resistance and service life of the hard sealing ring 7. Ring-shaped U-shaped pressing plates 4 are fixedly arranged on both the inner walls of the top and bottom of the annular airbag seal ring 1. And annular pads 8 are fixedly arranged on both the top of the floor bulkhead of the air supply system room 2 and the bottom of the drooping wall at the top of the liquid tank 3. Fixed components 5 are arranged at equal distances between the annular pad 8 and the ring-shaped U-shaped pressing plate 4. The fixed component 5 includes a bolt 501, a nut 502, and an anti-slip gasket 503. And the bolt 501 is fixed to the top of the ring-shaped U-shaped pressing plate 4 and extends outside the annular airbag seal ring 1. Through holes 504 for the bolt 501 to pass through at equal distances are provided on the flexible sealing lip 6, the hard sealing ring 7, the floor bulkhead of the air supply system room 2, the drooping wall at the top of the liquid tank 3, and the annular pad 8. The bolt 501 is in threaded cooperation with the nut 502 to press the anti-slip gasket 503 against the annular pad 8. The annular airbag seal ring 1 is placed at the movable gap between the floor bulkhead of the air supply system room 2 and the drooping wall at the top of the liquid tank 3 and is fixed by the bolt 501, the nut 502, and the anti-slip gasket 503 in the fixed component 5 to ensure the mechanical connection between the annular airbag seal ring 1, the floor bulkhead of the air supply system room 2, and the drooping wall at the top of the liquid tank 3 is stable, avoiding displacement or detachment after inflation. And the above-mentioned sealing structure can fully seal the movable gap formed between the top of the liquid tank and the air supply system, meeting the technical requirements of relative deformation and movement between the deformation of the top of the liquid tank and the surrounding ship deck components under conditions such as ship navigation, severe sea conditions, and temperature differences, and also meeting the sealing technical requirements between the top of the liquid tank and the air supply system room, avoiding the risk of ultra-low temperature gas leakage;

[0044] Wear compensation mechanism 10, which is installed between two annular U-shaped pressing plates 4 and is located inside the annular airbag seal ring 1. An inflation assembly 11 for driving the annular airbag seal ring 1 and the wear compensation mechanism 10 to work is arranged on the outer side of the annular airbag seal ring 1. The wear compensation mechanism 10 includes a mounting frame 1001 fixedly installed on the two annular U-shaped pressing plates 4, and fixed air cylinders 1002 are fixedly arranged on the two mounting frames 1001 at equal distances in a circular distribution. The inner walls of the fixed air cylinders 1002 are all inserted with jacking columns 1008, and reset springs 1009 are fixed between the bottom ends of the jacking columns 1008 and the inner walls of the fixed air cylinders 1002. The top ends of the jacking columns 1008 are fixed with the same annular jacking rod 1004. An annular groove is arranged on the surface of the jacking column 1008, and a piston sleeve 1010 is installed on the inner wall of the annular groove. The piston sleeve 1010 fits on the inner wall of the fixed air cylinder 1002. Branch air pipes 1007 are all fixed on the fixed air cylinders 1002, and an annular air pipe 1003 is fixed at the end of the branch air pipe 1007. A metal corrugated hose 1005 is installed between the two annular air pipes 1003. An annular seal groove 1006 is arranged on one side of the bottom of the hard seal ring 7, and the position of the annular seal groove 1006 corresponds to the position of the annular jacking rod 1004. The annular jacking rod 1004 is used to expand a part of the annular airbag seal ring 1 and fit it into the annular seal groove 1006. The inflation assembly 11 includes a second inflation pipe 1105 fixed on one side of the annular airbag seal ring 1 and a first inflation pipe 1104 fixed on one side of the metal corrugated hose 1005. Pressure valves 1103 are installed at one end of the first inflation pipe 1104 and one side of the second inflation pipe 1105. Three-way joints 1102 are installed at the air inlet ends of the two pressure valves 1103, and an air pump 1101 is installed at one end of the three-way joint 1102. Cavities 15 are arranged at equal distances on the annular wedge block 9, and pressure sensors 12 are installed on the inner walls of the cavities 15. The pressure sensors 12 are used to detect the sealing contact pressure between the annular wedge block 9 and the annular wedge groove 16. An alarm is arranged on the side of the first inflation pipe 1104 close to the pressure valve 1103, and the pressure sensors 12, the air pump 1101, the pressure valves 1103 and the alarm are electrically connected to a controller. The contact pressure between the annular wedge block 9 and the annular wedge groove 16 is continuously detected by the pressure sensors 12 and the data is transmitted to the controller. If the pressure value is normal, the current state is maintained; if the pressure is lower than the threshold value, it indicates that the sealing surface is worn or the gap is increased, and the wear compensation mechanism 10 and the inflation assembly 11 are triggered. At this time, the controller instructs the air pump 1101 to be turned on, and the fixed air cylinders 1002 are inflated through the first inflation pipe 1104, pushing the piston sleeve 1010, the jacking column 1008 and the annular jacking rod 1004 to move upward, jacking up a part of the annular airbag seal ring 1 to make it expand and embed into the annular seal groove 1006, filling the gap generated by wear and restoring the sealing pressure. After the compensation is completed, the pressure sensors 12 continue to monitor. If the pressure rises back to the normal range, the air pump 1101 is turned off;If there is a continuous abnormality or the maximum compensation times is exceeded, the controller triggers an alarm to facilitate manual maintenance prompt.

[0045] In the present invention, the annular airbag seal ring 1 is arranged at the movable gap between the floor enclosure wall 2 of the air supply system chamber and the drooping wall 3 at the top of the liquid tank, and the longitudinal section of the annular airbag seal ring 1 is an M-shaped curve telescopic structure. Inner convex reinforcing ribs 14 and outer convex reinforcing ribs 13 are fixedly arranged on the inner and outer arc surfaces of the airbag structure of the annular airbag seal ring 1 at equal distances, which are used to improve the ability of the annular airbag seal ring 1 to resist crack propagation and the damping effect.

[0046] In the present invention, the annular airbag seal ring 1 is composed of a cryogenic weather-resistant elastic layer 101, a reinforcing fiber support layer 102 and an anti-wear protection layer 103. The cryogenic weather-resistant elastic layer 101 adopts a composite material of polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer, which can maintain good elasticity and flexibility in a cryogenic environment of -162°C. The reinforcing fiber support layer 102 is woven from aramid fibers to provide high-strength support for the airbag. The anti-wear protection layer 103 adopts a polyurethane material to improve the wear resistance of the airbag surface.

[0047] A sealing method for an airbag type mechanical seal structure, which is applied to an airbag type mechanical seal structure, includes the following steps:

[0048] Step 1. Installation preparation: Place the annular airbag seal ring 1 at the movable gap between the floor enclosure wall 2 of the air supply system chamber and the drooping wall 3 at the top of the liquid tank, and conduct preliminary installation through the fixing component 5. At this time, the bolt 501 sequentially passes through the through holes 504 on the flexible sealing lip 6, the hard sealing ring 7, the floor enclosure wall 2 of the air supply system chamber, the drooping wall 3 at the top of the liquid tank and the annular backing plate 8, puts on the anti-slip gasket 503 and then screws on the nut 502, and makes the annular wedge block 9 on the flexible sealing lip 6 fit into the annular wedge groove 16 on the hard sealing ring 7 to form an initial sealing surface, ensuring the preliminary fixation of the position of the annular airbag seal ring 1 with the two side walls, and the annular U-shaped pressing plate 4 is closely attached to the annular backing plate 8;

[0049] Step 2. Initial inflation sealing: Turn on the air pump 1101, and inflate the annular airbag seal ring 1 through the tee 1102 and the second inflatable pipe 1105. The air pressure causes the annular airbag seal ring 1 to expand, making the annular wedge block 9 fit more closely into the annular wedge groove 16. At the same time, the grid maze contact surface 17 on the top surface of the flexible sealing lip 6 contacts the bottom surface of the hard sealing ring 7 to increase the friction and sealing effect. When the air pressure reaches the preset initial value, close the air pressure valve 1103 on the second inflatable pipe 1105 to stop inflating the annular airbag seal ring 1, and then tighten the nut 502.

[0050] Step 3. Pressure monitoring and compensation preparation: The pressure sensor 12 inside the annular wedge 9 is used to detect the sealing contact pressure between it and the annular wedge groove 16 in real time, and the data is transmitted to the controller. The controller analyzes the pressure data. If the pressure value is within the normal range, the current sealing state is maintained; if the pressure value is lower than the set threshold, it indicates that there may be wear on the sealing surface or the gap has increased, and then enter the next step.

[0051] Step 4. Wear compensation inflation: In Step 3, the controller issues an instruction to turn on the air pump 1101 and open the pneumatic valve 1103 on the first air charging pipe 1104. The gas enters the fixed air cylinder 1002 through the branch air pipe 1007, the annular air pipe 1003 and the metal corrugated hose 1005. The air pressure pushes the piston sleeve 1010, and the jacking column 1008 drives the annular jacking rod 1004 to move upward, jacking up a part of the annular airbag seal ring 1, making it expand and fit into the annular seal groove 1006 at the bottom of the hard seal ring 7 to compensate for the gap caused by wear and restore the sealing pressure.

[0052] Step 5. Continuous monitoring and dynamic adjustment: The pressure sensor 12 continuously monitors the sealing contact pressure. The controller adjusts the working state of the air pump 1101 and the opening and closing of the pneumatic valve 1103 in real time according to the pressure change to ensure that the sealing surface always maintains a good sealing effect. If the pressure value is continuously abnormal or exceeds the set maximum compensation times, the controller controls the alarm to work and emits an alarm signal to prompt the staff to carry out maintenance and repair.

[0053] In summary, the working principle of the present invention: The annular airbag seal ring 1 is placed at the movable gap between the floor enclosure 2 of the air supply system chamber and the drooping wall 3 at the top of the liquid tank, and is initially fixed by the bolts 501, nuts 502 and anti-slip washers 503 in the fixing assembly 5, so that the annular wedge 9 of the flexible sealing lip 6 is embedded in the annular wedge groove 16 of the hard seal ring 7 to form an initial mechanical sealing surface, and at the same time ensure that the annular U-shaped pressing plate 4 is closely attached to the annular backing plate 8;

[0054] Next, turn on the air pump 1101. Inflate the annular airbag seal ring 1 through the three-way joint 1102 and the second inflatable tube 1105. The airbag expands due to the air pressure. Its M-curve type telescopic structure and the inner convex reinforcing ribs 14 and the outer convex reinforcing ribs 13 make the expansion force evenly distributed, pushing the flexible sealing lip 6 to tightly squeeze the hard sealing ring 7. At this time, the grid labyrinth contact surface 17 contacts the wear-resistant coating 18, strengthening the sealing effect by increasing the frictional resistance and the contact area. The fitting surface of the annular wedge block 9 and the annular wedge groove 16 is further pressed tightly due to the expansion of the airbag, forming a double seal of "mechanical wedge fit + air pressure drive". When the air pressure reaches the preset initial value, close the air pressure valve 1103 to stop inflation, complete the initial seal, and further tighten the nut 502. Thus, the adopted sealing structure can fully seal the movable gap formed between the top of the liquid tank and the gas supply system, meeting the technical requirements of the relative deformation and movement between the deformation of the top of the liquid tank and the surrounding ship's deck components under conditions such as ship navigation, severe sea conditions, and temperature differences, and also meeting the sealing technical requirements between the top of the liquid tank and the gas supply system chamber;

[0055] Then, continuously detect the sealing contact pressure through the pressure sensor 12 inside the annular wedge block 9 and transmit the data to the controller. If the pressure value is normal, maintain the current state; if the pressure is lower than the threshold, indicating that the sealing surface is worn or the gap has increased, trigger the wear compensation mechanism. At this time, the controller commands to turn on the air pump 1101 and inflate the fixed air cylinder 1002 of the wear compensation mechanism 10 through the first inflatable tube 1104. The air pressure pushes the piston sleeve 1010, causing the jacking column 1008 to overcome the resistance of the return spring 1009 and drive the annular jacking rod 1004 to move upward, jacking up a part of the annular airbag seal ring 1, making it expand and embed into the annular seal groove 1006 of the hard sealing ring 7 to fill the gap generated by wear and restore the sealing pressure. After the compensation is completed, the pressure sensor 12 continues to monitor. If the pressure rises back to the normal range, turn off the air pump 1101; if it remains abnormal continuously or exceeds the maximum compensation times, the controller triggers the alarm to prompt manual maintenance.

[0056] Combined with the current actual requirements, the above-mentioned implementation method adopted in this application, the scope of protection is not limited to this. Within the knowledge scope of those skilled in the art, various changes made without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. An airbag type mechanical seal structure, characterized in that, Including: An annular airbag sealing ring (1), a floor bulkhead of the air supply system chamber (2), and a drooping wall at the top of the liquid tank (3). Flexible sealing lips (6) in a ring shape are fixedly arranged at both the top and the bottom of the annular airbag sealing ring (1). Hard sealing rings (7) are fixedly arranged at both the bottom of the floor bulkhead of the air supply system chamber (2) and the top of the drooping wall at the top of the liquid tank (3). The hard sealing ring (7) and the flexible sealing lip (6) are connected in a fitting manner. Ring-shaped U-shaped pressing plates (4) are fixedly arranged on both the inner walls of the top and the bottom of the annular airbag sealing ring (1). Annular backing plates (8) are fixedly arranged at both the top of the floor bulkhead of the air supply system chamber (2) and the bottom of the drooping wall at the top of the liquid tank (3). Fixed components (5) are arranged at equal distances between the annular backing plate (8) and the ring-shaped U-shaped pressing plate (4); A wear compensation mechanism (10) is installed between the two ring-shaped U-shaped pressing plates (4) and is located inside the annular airbag sealing ring (1). An inflation assembly (11) for driving the annular airbag sealing ring (1) and the wear compensation mechanism (10) to work is arranged on the outer side of the annular airbag sealing ring (1).

2. The airbag type mechanical seal structure according to claim 1, characterized in that An annular wedge groove (16) is arranged at the bottom near the middle of the hard sealing ring (7). An annular wedge block (9) that fits in the annular wedge groove (16) is fixed to the top of the flexible sealing lip (6). Both the flexible sealing lip (6) and the annular wedge block (9) are made of a composite of silicone rubber and carbon fiber.

3. The airbag type mechanical seal structure according to claim 2, characterized in that, The fixed component (5) includes a bolt (501), a nut (502), and an anti-slip gasket (503). The bolt (501) is fixed to the top of the ring-shaped U-shaped pressing plate (4) and extends outside the annular airbag sealing ring (1). Through holes (504) for the bolt (501) to pass through at equal distances are provided on the flexible sealing lip (6), the hard sealing ring (7), the floor bulkhead of the air supply system chamber (2), the drooping wall at the top of the liquid tank (3), and the annular backing plate (8). The bolt (501) is in threaded cooperation with the nut (502) to press the anti-slip gasket (503) against the annular backing plate (8).

4. The airbag type mechanical seal structure according to claim 3, characterized in that, The annular airbag sealing ring (1) is arranged at the movable gap between the floor bulkhead of the air supply system chamber (2) and the drooping wall at the top of the liquid tank (3). The longitudinal section of the annular airbag sealing ring (1) is an M-curve-shaped telescopic structure. Inner protruding reinforcing ribs (14) and outer protruding reinforcing ribs (13) are fixedly arranged on the inner and outer arc surfaces of the bag-shaped structure of the annular airbag sealing ring (.) 5. The airbag type mechanical seal structure according to claim 4, characterized in that, The annular airbag sealing ring (1) is composed of a cryogenic weather-resistant elastic layer (101), a reinforcing fiber support layer (102), and an anti-wear protection layer (103). The cryogenic weather-resistant elastic layer (101) is made of a composite material of polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer. The reinforcing fiber support layer (102) is woven from aramid fibers. The anti-wear protection layer (103) is made of polyurethane material.

6. The airbag type mechanical seal structure according to claim 5, characterized in that, A grid maze contact surface (17) is arranged on the top surface of the flexible sealing lip (6).

7. The airbag type mechanical seal structure according to claim 6, characterized in that, A wear-resistant coating (18) is arranged on the bottom surface of the hard sealing ring (7).

8. The airbag type mechanical seal structure according to claim 7, characterized in that, The wear compensation mechanism (10) includes a mounting bracket (1001) fixedly installed on the two annular U-shaped pressing plates (4), and fixed air cylinders (1002) are fixedly arranged on the two mounting brackets (1001) in an equidistant and annular distribution. The inner walls of the fixed air cylinders (1002) are all inserted with jacking columns (1008), and a return spring (1009) is fixed between the bottom ends of the jacking columns (1008) and the inner walls of the fixed air cylinders (1002). The top ends of the jacking columns (1008) are fixed with the same annular jacking rod (1004). An annular groove is arranged on the surface of the jacking column (1008), and a piston sleeve (1010) is installed on the inner wall of the annular groove. The piston sleeve (1010) is attached to the inner wall of the fixed air cylinder (1002). The fixed air cylinders (1002) are all fixed with branch air pipes (1007), and the ends of the branch air pipes (1007) are fixed with an annular air pipe (1003). A same metal corrugated hose (1005) is installed between the two annular air pipes (1003). On one side of the bottom of the hard seal ring (7), an annular seal groove (1006) is arranged, and the position of the annular seal groove (1006) corresponds to the position of the annular jacking rod (1004). The annular jacking rod (1004) is used to locally expand the annular airbag seal ring (1) and fit it into the annular seal groove (1006).

9. The airbag type mechanical seal structure according to claim 8, characterized in that, The air charging assembly (11) includes a second air charging pipe (1105) fixed on one side of the annular airbag seal ring (1) and a first air charging pipe (1104) fixed on one side of the metal corrugated hose (1005). Pressure valves (1103) are installed at one end of the first air charging pipe (1104) and one side of the second air charging pipe (1105). The intake ends of the two pressure valves (1103) are installed with a tee joint (1102), and an air pump (1101) is installed at one end of the tee joint (1102). Cavities (15) are arranged at equidistant intervals on the annular wedge block (9), and pressure sensors (12) are installed on the inner walls of the cavities (15). The pressure sensors (12) are used to detect the sealing contact pressure between the annular wedge block (9) and the annular wedge groove (16). An alarm is arranged on one side of the first air charging pipe (1104) close to the pressure valve (1103), and the pressure sensors (12), the air pump (1101), the pressure valves (1103) and the alarm are electrically connected to a controller.

10. A sealing method for a balloon-type mechanical seal structure, applied to a balloon-type mechanical seal structure as described in any one of claims 1-9, characterized in that, Including the following steps: Step 1. Installation Preparation: Place the annular airbag seal ring (1) at the movable gap between the floor enclosure (2) of the air supply system chamber and the drooping wall (3) at the top of the liquid tank, and conduct preliminary installation through the fixing component (5). At this time, the bolt (501) sequentially passes through the through holes (504) on the flexible sealing lip (6), the hard sealing ring (7), the floor enclosure (2) of the air supply system chamber, the drooping wall (3) at the top of the liquid tank, and the annular backing plate (8), puts on the anti-slip gasket (503) and then screws on the nut (502), and makes the annular wedge block (9) on the flexible sealing lip (6) fit into the annular wedge groove (16) of the hard sealing ring (7) to form an initial sealing surface, ensuring that the annular airbag seal ring (1) is initially fixed in position with the two side walls, and the annular U-shaped pressing plate (4) is in close contact with the annular backing plate (8); Step 2. Initial Inflation Sealing: Turn on the air pump (1101), and inflate the annular airbag seal ring (1) through the tee (1102) and the second inflatable pipe (1105). The air pressure causes the annular airbag seal ring (1) to expand, making the annular wedge block (9) fit more tightly into the annular wedge groove (16). At the same time, the grid maze contact surface (17) on the top surface of the flexible sealing lip (6) contacts the bottom surface of the hard sealing ring (7) to increase the friction and sealing effect. When the air pressure reaches the preset initial value, close the air pressure valve (1103) on the second inflatable pipe (1105) to stop inflating the annular airbag seal ring (1), and then tighten the nut (502); Step 3. Pressure Monitoring and Compensation Preparation: Real-time detect the sealing contact pressure between the annular wedge block (9) and the annular wedge groove (16) through the pressure sensor (12) inside the annular wedge block (9), and transmit the data to the controller. The controller analyzes the pressure data. If the pressure value is within the normal range, maintain the current sealing state; if the pressure value is lower than the set threshold, it indicates that there may be wear or an increased gap on the sealing surface, and enter the next step; Step 4. Wear Compensation Inflation: In Step 3, the controller issues an instruction to turn on the air pump (1101) and open the air pressure valve (1103) on the first inflatable pipe (1104). The gas enters the fixed air cylinder (1002) through the branch pipe (1007), the annular air pipe (1003), and the metal corrugated hose (1005). The air pressure pushes the piston sleeve (1010), and the jacking column (1008) drives the annular jacking rod (1004) to move upward, jacking up a part of the annular airbag seal ring (1) to make it expand and fit into the annular sealing groove (1006) at the bottom of the hard sealing ring (7) to compensate for the gap caused by wear and restore the sealing pressure; Step 5. Continuous Monitoring and Dynamic Adjustment: The pressure sensor (12) continuously monitors the sealing contact pressure, and the controller adjusts the working state of the air pump (1101) and the opening and closing of the air pressure valve (1103) in real time according to the pressure change to ensure that the sealing surface always maintains a good sealing effect. If the pressure value continues to be abnormal or exceeds the set maximum compensation times, control the alarm to work through the controller to issue an alarm signal to prompt the staff to carry out maintenance and repair.

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