Gas jacking sealing device of low-temperature storage tank and gas jacking construction method of low-temperature storage tank

Abstract

The invention discloses a low-temperature storage tank gas jacking sealing device and a low-temperature storage tank gas jacking construction method, and relates to the technical field of LNG (Liquefied Natural Gas) low-temperature storage tank construction. By arranging a sealing mechanism and a plurality of lifting mechanisms, in a vault ascending stage (namely, the longest and most critical construction period), the sealing mechanism is in a walking separation state and maintains a continuous isolation gas ring; at the moment, no solid contact part exists between the vault and the inner wall of the tank body, so that continuous sliding friction generated between the traditional rigid sealing strip, brush sealing or rubber scraping plate and the tank wall in the long-distance climbing process is completely eliminated. The friction elimination directly avoids the damage of serious abrasion, tearing, chipping and the like caused by repeated scraping and abrasion of the sealing structure, and also avoids the damage of scratches, local cold hardening, microcrack sources and the like caused by long-term hard friction on the 9% Ni steel surface of the inner wall of the tank body, so that the integrity of the final inner wall surface of the tank body is remarkably improved, and the service life of the final inner wall surface of the tank body is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of LNG cryogenic storage tank construction technology, and in particular to a cryogenic storage tank gas lifting sealing device and a cryogenic storage tank gas lifting construction method. Background Technology

[0002] LNG cryogenic storage tanks are the main equipment used to store large quantities of LNG natural gas. In the existing technology, when constructing LGN cryogenic storage tanks, the dome is usually raised to the design height using a gas jacking method.

[0003] However, during current gas jacking operations, a sealing structure needs to be installed between the dome and the tank wall to prevent gas leakage during dome lifting. A common sealing device is installed directly at the edge of the dome, fitting snugly against the tank wall to achieve a seal. While this method ensures a tight seal, friction between the sealing device and the tank wall occurs during actual lifting, causing damage and ultimately affecting the lifespan of the tank wall. Summary of the Invention

[0004] The main objective of this invention is to propose a gas lifting sealing device and a gas lifting construction method for cryogenic storage tanks, aiming to solve the technical problem that in the actual lifting process, the sealing device will rub against the tank wall, causing damage to the sealing device and ultimately affecting the service life of the tank wall.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a cryogenic storage tank gas lifting and sealing device. The cryogenic storage tank includes a tank body and an arch formed within the tank body. The arch is located at the bottom of the tank body, and a gas storage space for storing lifting gas is formed between the arch and the tank body. An air pump is connected to the gas storage space, and the air pump can pump gas into the gas storage space to lift the arch from the bottom of the tank body to the top of the tank body, thereby enclosing the arch and forming the cryogenic storage tank. The gas lifting and sealing device includes:

[0006] A sealing mechanism is provided around the outer periphery of the dome. The sealing mechanism has a sealing contact state and a disengaged, mobile state. In the sealing contact state, the sealing mechanism abuts against the inner wall of the tank, causing the dome to suspend within the tank. In the disengaged, mobile state, the sealing mechanism ejects a gas flow towards the gas storage space to counteract the gas flow within the gas storage space and form an insulating gas ring. Multiple lifting mechanisms are distributed circumferentially on the inner wall of the tank. All lifting mechanisms are located above the dome and connected to the dome. All lifting mechanisms can drive the dome to climb along the inner wall of the tank when the sealing mechanism is in the disengaged walking state, and can also suspend the dome inside the tank when the sealing mechanism is in the sealed state.

[0007] In one embodiment, the sealing mechanism includes: A connecting ring is provided around the outer periphery of the arch, and an annular mounting position is formed on the connecting ring around its outer periphery; A sealing component is installed at the mounting position and surrounds the outer periphery of the connecting ring. An air cavity is formed within the sealing component, and multiple air holes, each communicating with the air cavity, are formed on the sealing component at circumferential intervals. Each air hole is connected to the lifting mechanism via an air pipe, allowing the air cavity to switch between an inflated and deflated state. When the air cavity is in the inflated state, the sealing component abuts against the inner wall of the tank to form a sealing contact. An isolation ring forming component is installed on the connecting ring and is located below the sealing component. An air ring forming chamber is formed inside the isolation ring forming component and is connected to the lifting mechanism through a pipe. The isolation ring forming component can eject airflow from the ring forming chamber and form the isolation ring when the sealing component is in the venting state.

[0008] In one embodiment, the sealing component includes a wear-resistant layer, a tear-resistant layer, an airtight barrier layer, a buffer layer, and an air storage layer sequentially arranged from the outside to the inside. The wear-resistant layer is connected to the installation position, and the air storage layer forms the air cavity. The air pores pass through the wear-resistant layer, the tear-resistant layer, the airtight barrier layer, the buffer layer, and the air storage layer sequentially from the outside to the inside.

[0009] In one embodiment, a groove is formed on the connecting ring arranged circumferentially, and at least a portion of the wear-resistant layer is engaged in the groove.

[0010] In one embodiment, the isolation gas ring forming component includes an integrally formed base ring, a first blocking ring, and a second blocking ring. The first blocking ring is located above the second blocking ring. The gas ring forming chamber is formed between the base ring, the first blocking ring, and the second blocking ring. The gas ring forming chamber has an annular air passage disposed toward the inner wall of the tank.

[0011] In one embodiment, the first blocking ring is located on one side of the gas ring forming chamber and is arranged radially downward, while the second blocking ring is located on one side of the gas ring forming chamber and is arranged radially upward, so that the gas ring forming chamber gradually narrows radially.

[0012] In one embodiment, the diameter of the second blocking ring is smaller than the diameter of the first blocking ring.

[0013] In one embodiment, the lifting mechanism includes: At least one guide rail is vertically mounted on the inner wall of the tank. At least two sets of fixing seats are provided, which are distributed vertically at intervals at both ends of the guide rail, and all the fixing seats are connected to the inner wall of the tank. A slider, which slides in conjunction with the guide assembly; and... A lifting cylinder is installed on the slider, the telescopic end of the lifting cylinder is connected to the arch, and the lifting cylinder is connected to the sealing mechanism through a pipeline.

[0014] In one embodiment, the guide rail is provided with vertically spaced abutment grooves, and the slider is rotatably provided with abutment blocks, which can abut against any of the abutment grooves.

[0015] Based on the same technical concept, in a second aspect, the present invention also proposes a method for gas jacking construction of a cryogenic storage tank, applying the cryogenic storage tank gas jacking sealing device described in the first aspect, the construction method comprising the following steps: The sealing mechanism is installed on the outer periphery of the already constructed dome; The sealing mechanism ejects a first gas flow into the gas storage space at a preset speed. A second airflow is ejected into the gas storage space via the air pump; When the first airflow converges with the first airflow at the preset speed, the isolation air ring is formed; The second airflow continues to be pumped into the gas storage space through the air pump to push the dome up along the inner wall of the tank and carry out air jacking construction.

[0016] The technical solution of this invention, through the setting of a sealing mechanism and multiple lifting mechanisms, ensures that during the arch's ascent phase (i.e., the longest and most critical construction period), the sealing mechanism is in a disengaged state and maintains a continuous isolation air ring. At this time, there are no solid contact components between the arch and the inner wall of the tank, thus completely eliminating the continuous sliding friction generated between traditional rigid sealing strips, brush seals, or rubber scrapers and the tank wall during long-distance ascent. This elimination of friction directly avoids severe wear, tearing, and chipping damage caused by repeated scraping of the sealing structure itself, and also avoids damage such as scratches, localized work hardening, and microcrack sources on the 9% Ni steel surface of the inner wall of the tank due to long-term hard friction, thereby significantly improving the integrity and service life of the final inner wall surface of the tank. Simultaneously, the formation of the isolation air ring utilizes the counter-current effect between the high-speed airflow and the main rising airflow, effectively blocking the rising gas without relying on solid seals. This prevents a large amount of rising gas from leaking upwards from the arch edge into the already raised area, maintaining pressure stability within the bottom gas storage space and reducing the ineffective power consumption of the air pump and the total gas consumption. Once the arch reaches the designed height, the sealing mechanism switches to the contact sealing state. At this time, the radial contact provides mechanically reliable circumferential positioning and airtight barrier, creating a stable low-leakage environment for subsequent welding operations. This avoids repeated adjustments and gas waste caused by unstable airflow control at the end of the jacking stage in traditional construction. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the cryogenic storage tank gas lifting sealing device provided by the present invention in use. Figure 2 for Figure 1 The diagram shows the internal structure of the cryogenic storage tank gas lifting sealing device in use. Figure 3 for Figure 2 The example shows a schematic diagram of the sealing device in its installed state; Figure 4 for Figure 3 A schematic diagram of the sealing device shown in the example; Figure 5 for Figure 4 A schematic diagram of the internal structure of the sealing mechanism in the example; Figure 6 for Figure 5An enlarged structural diagram of part A in the example; Figure 7 for Figure 4 The example above shows a schematic diagram of the lifting mechanism. Figure 8 This is a flowchart illustrating the gas jacking construction method for a cryogenic storage tank, as exemplified by the present invention.

[0019] Figure label: 100. Tank body; 200. Dome; 300. Gas storage space; 400. Air pump; 500. Sealing mechanism; 600. Lifting mechanism; 510. Connecting ring; 520. Sealing component; 530. Gas chamber; 540. Air hole; 550. Isolation ring forming component; 521. Wear-resistant layer; 522. Tear-resistant layer; 523. Airtight barrier layer; 524. Buffer layer; 525. Gas storage layer; 511. Slot; 551. Base ring; 552. First blocking ring; 553. Second blocking ring; 610. Guide rail; 620. Fixing seat; 630. Sliding block; 640. Lifting cylinder; 650. Abutment groove; 660. Abutment block.

[0020] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0024] In traditional LNG cryogenic storage tank gas lifting construction technology, sealing devices are installed at the edge of the dome and fitted against the tank wall to achieve a sealing function. During the gas lifting process, relative movement occurs between the sealing device and the tank wall, resulting in friction, which damages the sealing device and affects the service life of the tank wall. Furthermore, this friction problem reduces the reliability of the sealing system and the continuity of the construction process, making it difficult to maintain the sealing integrity of the gas storage space, thus hindering the stable lifting of the dome.

[0025] For example, during the gas jacking construction of a cryogenic storage tank, as the dome is lifted from the bottom to the top of the tank, the sealing device continuously contacts and slides against the inner surface of the tank wall. Due to contact stress and movement, the surface of the sealing material is worn, the sealing performance is weakened, and gas leakage is triggered. Specifically, as the jacking height increases, the friction between the sealing device and the tank wall intensifies, leading to a deterioration of the sealing effect, hindering the construction progress, and making it difficult to maintain the stable suspension state of the dome.

[0026] This invention proposes a gas lifting and sealing device for cryogenic storage tanks and a gas lifting construction method for cryogenic storage tanks.

[0027] Please see Figures 1 to 8For ease of understanding, this cryogenic storage tank gas lifting and sealing device includes a cryogenic storage tank comprising a tank body 100 and an arched dome 200 formed within the tank body 100. The arched dome 200 is located at the bottom of the tank body 100. A gas storage space 300 for storing lifting gas is formed between the arched dome 200 and the tank body 100. An air pump 400 is connected to the gas storage space 300, which pumps gas into the gas storage space 300 to lift the arched dome 200 from the bottom of the tank body 100 to the top of the tank body 100, thus forming a cryogenic storage tank. The gas lifting and sealing device includes a sealing mechanism 500 and multiple lifting mechanisms 600. The sealing mechanism 500 is located around the outer periphery of the arched dome 200 and has a sealing state and a disengaged, moving state. When in the sealed state, the sealing mechanism 500 abuts against the inner wall of the tank 100, and the dome 200 is suspended inside the tank 100. When out of the traveling state, the sealing mechanism 500 can spray airflow towards the gas storage space 300 to counteract the airflow in the gas storage space 300 and form an isolation air ring. Multiple lifting mechanisms 600 are distributed circumferentially on the inner wall of the tank 100. All lifting mechanisms 600 are located above the dome 200 and are connected to the dome 200. All lifting mechanisms 600 can drive the dome 200 to climb along the inner wall of the tank 100 when the sealing mechanism 500 is out of the traveling state. All lifting mechanisms 600 can also suspend the dome 200 inside the tank 100 when the sealing mechanism 500 is in the sealed state.

[0028] Specifically, the gas jacking construction of the cryogenic storage tank involves the inner tank of a 150,000 cubic meter full-containment LNG storage tank. The tank body 100 is made of 9% Ni steel with an inner diameter of approximately 50 meters. The dome 200 was prefabricated at the bottom of the tank body 100 using a ground-mounted frame during the initial construction phase. At this stage, the dome 200 is located entirely below the tank body 100, forming a closed gas storage space 300 between the dome 200 and the bottom of the tank body 100. This gas storage space 300 is connected to 6–10 low-pressure, high-flow-rate gas pumps 400 (each with a flow rate typically 8000–15000 m³ / h and an outlet pressure range of 300–1200 Pa gauge pressure) located at the bottom of the tank. The gas pumps 400 continuously pump clean compressed air or nitrogen into the gas storage space 300 as the jacking power gas.

[0029] The air-lift sealing device in this embodiment mainly includes a sealing mechanism 500 and multiple lifting mechanisms 600.

[0030] The sealing mechanism 500 is ring-shaped and is fixed to the outer periphery of the arch 200. The sealing mechanism 500 has two switchable working states: abutting and sealing state and disengaging and moving state.

[0031] In the contact and sealing state, the outer periphery of the sealing mechanism 500 expands or extends radially outward, reliably fitting and contacting the inner wall of the tank 100. At this time, the sealing mechanism 500 not only prevents gas from leaking upward, but also provides radial positioning and support for the dome 200, so that the dome 200 is suspended in the internal space of the tank 100 and does not make hard contact with the bottom of the tank or other structures.

[0032] When disengaged from its traveling state, the outer periphery of the sealing mechanism 500 retracts radially inward, forming a significant radial gap (typically 5–25 mm) with the inner wall of the tank 100. At this time, the lower structure of the sealing mechanism 500 can eject a high-speed airflow towards the gas storage space 300 (i.e., downward). This ejected airflow, along with the rising airflow (secondary airflow) continuously pumped into the gas storage space 300 by the air pump 400, experiences strong collision, shearing, and entrainment in the area below the sealing mechanism 500. This creates a continuous and stable high-speed air curtain within the annular gap between the outer periphery of the dome 200 and the inner wall of the tank 100; this air curtain is the isolation air ring. The presence of the isolation air ring effectively prevents the main rising airflow from passing upward through this gap into the upper region of the dome 200.

[0033] Multiple lifting mechanisms 600 (eight sets in this embodiment, evenly spaced at 60° intervals along the inner circumference of the tank 100) are all fixedly installed on the inner wall of the tank 100, and their installation height is all above the current height of the dome 200. Each set of lifting mechanisms 600 is connected to the top structure or edge reinforcing ring of the dome 200 via hinges, ball joints, or flexible connectors.

[0034] When the sealing mechanism 500 is in the disengaged walking state (i.e., detached from the tank wall and the isolation air ring has been stably established), all lifting mechanisms 600 extend or pull synchronously and slowly, driving the arch 200 to climb vertically upward along the inner wall of the tank 100. At this time, the main upward power of the arch 200 is still provided by the buoyancy of the bottom gas. The lifting mechanism 600 mainly undertakes the functions of guidance, synchronous correction, prevention of deflection and local weight distribution.

[0035] Once the dome 200 rises to the design elevation or the preset stop position, the sealing mechanism 500 switches to the abutment sealing state. At this time, the lifting mechanism 600 stops extending or switches to the pressure holding / micro-tension state, so that the dome 200 is stably suspended in the tank 100 by the bottom air pressure and the radial abutment support of the sealing mechanism 500 until the permanent welding connection between the dome 200 and the tank wall is completed.

[0036] In this embodiment, during the rising phase of the dome 200 (i.e., the longest and most critical construction period), the sealing mechanism 500 is in a disengaged state and maintains a continuous isolation air ring. At this time, there are no solid contact parts between the dome 200 and the inner wall of the tank 100, thus completely eliminating the continuous sliding friction between traditional rigid sealing strips, brush seals, or rubber scrapers and the tank wall during long-distance climbing. This elimination of friction directly avoids severe wear, tearing, and chipping damage caused by repeated scraping of the sealing structure itself. It also avoids scratches, localized cold work hardening, and microcrack sources on the 9% Ni steel surface of the inner wall of the tank 100 due to long-term hard friction, thereby significantly improving the integrity and service life of the final inner wall surface of the tank 100.

[0037] Meanwhile, the formation of the isolation ring utilizes the counteracting effect of the high-speed airflow and the main jacking airflow, effectively blocking the jacking gas without relying on solid seals. This prevents a large amount of jacking gas from leaking upwards from the edge of the dome 200 into the already raised area, maintaining the pressure stability within the bottom gas storage space 300 and reducing the ineffective power consumption of the air pump 400 and the total gas consumption.

[0038] Once the arch 200 reaches the designed height, the sealing mechanism 500 switches to the contact sealing state. At this time, the radial contact provides mechanically reliable circumferential positioning and airtight barrier, creating a stable low-leakage environment for subsequent welding operations. This avoids repeated adjustments and gas waste caused by unstable airflow control at the end of the jacking stage in traditional construction.

[0039] In one embodiment, the isolation air ring is formed by a narrow-slit annular injection method with an outlet velocity of 80-160 m / s. The injection angle is tilted downwards by 5°-15° relative to the horizontal plane to enhance the entrainment and counter-current effect with the rising main airflow, thereby further improving the rigidity and continuity of the air curtain.

[0040] In one embodiment, the number of lifting mechanisms 600 is any one of 4, 6, 8 or 10 groups. The number of groups is determined based on the diameter of the tank 100, the weight of the dome 200 and the maximum allowable local off-center load. 8 groups are preferred to balance the difficulty of synchronous control and structural economy.

[0041] In one embodiment, the lifting mechanism 600 is driven by a pneumatic telescopic cylinder. The working pressure of the cylinder and the pneumatic control of the sealing mechanism 500 share the same low-pressure air source system. The solenoid valve group enables rapid switching between the disengagement walking state and the contact sealing state (switching time ≤ 8 seconds).

[0042] Through the above-mentioned specific implementation methods, this application eliminates the wear problem that is inevitable in traditional solid friction sealing methods by using a combination of "switched-state sealing mechanism 500 + isolation air ring + upper lifting mechanism 600" during the jacking process of the dome 200. At the same time, it ensures the airtightness requirements during construction and the stable support requirements after positioning. Thus, without sacrificing the sealing effect, it significantly improves the construction quality, reduces the maintenance risk of the tank 100 in the later stage, and extends the overall service life of the cryogenic storage tank.

[0043] In one embodiment, the sealing mechanism 500 includes a connecting ring 510, a sealing component 520, and an isolation air ring forming component 550. The connecting ring 510 surrounds the outer periphery of the dome 200 and has an annular mounting position surrounding its outer periphery. The sealing component 520 is mounted at the mounting position and surrounds the outer periphery of the connecting ring 510. An air cavity 530 is formed within the sealing component 520, and a plurality of air holes 540, each communicating with the air cavity 530, are formed on the sealing component 520. The air holes 540 are spaced apart circumferentially, and each air hole 540 is connected to the lifting mechanism 600 through an air pipe, so that... The air chamber 530 can switch between an inflated state and a deflated state. When the air chamber 530 is in the inflated state, the sealing component 520 abuts against the inner wall of the tank 100 to form a sealing abutment. The isolation air ring forming component 550 is installed on the connecting ring 510 and is located below the sealing component 520. An air ring forming chamber is formed inside the isolation air ring forming component 550, and the air ring forming chamber is connected to the lifting mechanism 600 through a pipe. When the sealing component 520 is in the deflated state, the isolation air ring forming component 550 can eject airflow from the air ring forming chamber to form the isolation air ring.

[0044] Specifically, the connecting ring 510 is made of low-magnetic stainless steel sheet (e.g., 316L or 304L) with a thickness of 16–22 mm, rolled into shape and welded closed. Its inner side is reliably fixed to the outer peripheral edge reinforcing ring of the dome 200 by high-strength bolt groups or continuous fillet welds. A continuous annular mounting position is machined on the outer peripheral surface of the connecting ring 510. This mounting position has a stepped cross-section (L-shaped or T-shaped) and a width of 120–180 mm, serving as the mounting reference surface for the sealing component 520. At the root of this annular mounting position, near the body of the connecting ring 510, a rectangular groove 511 is also machined, which is continuously or segmented along the entire circumference, for mechanical positioning of the subsequent wear-resistant layer 521.

[0045] The sealing component 520 is an integrally annular, inflatable, gas-elastic body with a roughly rectangular or trapezoidal cross-section. Its inner mounting reference surface is interference-fitted with the annular mounting position of the connecting ring 510 or fixed by a slot 511 and a pressure plate, thereby allowing the sealing component 520 to be entirely surrounded by the outer periphery of the connecting ring 510. A closed annular air chamber 530 is formed along the entire circumference inside the sealing component 520. The volume of this air chamber 530 is typically controlled to be approximately 1.8–3.2 liters per meter of circumference, depending on the tank diameter. A series of vents 540 are evenly spaced along the circumference at the top of the sealing component 520. All vents 540 radially penetrate the wall thickness of the sealing component 520 and communicate with the internal air chamber 530. Each vent 540 is connected to the air supply distribution main of the lifting mechanism 600 located above the tank wall via an independent or parallel flexible pressure-resistant air pipe (typically made of polyurethane or nylon, with a diameter of φ6–φ10 mm). By controlling the solenoid valve and pressure reducing valve in the gas supply system, the gas chamber 530 can be quickly switched between the inflation and deflation states.

[0046] When the air chamber 530 is in an inflated state, the sealing component 520 expands radially under the action of air pressure, and its outer side reliably abuts against and presses against the inner wall of the tank 100, forming a continuous circumferential airtight contact, thereby achieving the abutment and sealing state described in the previous embodiment. At this time, the dome 200 relies on the bottom air pressure and the circumferential abutment to maintain a stable suspension.

[0047] The isolation ring forming component 550 is fixedly installed on the lower flange or lower step surface of the connecting ring 510, with its installation height directly below the sealing component 520 (axial spacing is typically 10–35 mm). The isolation ring forming component 550 internally machined or welded to form an annular ring forming chamber that opens towards the inner wall of the tank 100. This chamber is connected to the air supply system of the lifting mechanism 600 via one or more main air supply pipes of larger diameter. When the sealing component 520 is in the venting state (i.e., radially contracted and detached from the tank wall), high-pressure gas is introduced into the ring forming chamber. The gas is ejected from the annular slit towards the inner wall of the tank 100, creating a strong counter-current, shearing, and entrainment effect with the rising main airflow provided by the air pump 400 within the gas storage space 300. This forms a high-speed, stable air curtain, approximately 15–40 mm thick, surrounding the entire circumference within the annular gap between the outer periphery of the dome 200 and the tank wall—the isolation ring.

[0048] In this embodiment, during the rising phase of the dome 200, the sealing component 520 remains in a vented state, radially contracting to form a significant gap of 5–25 mm between itself and the tank wall, eliminating any solid contact. Simultaneously, the isolating gas ring forming component 550 continuously sprays gas at high speed, forming a dynamic air curtain barrier layer. This air curtain effectively prevents the main lifting gas from leaking upwards into the already raised area, thereby maintaining the pressure stability of the gas storage space 300 without using any sliding contact seals. At this point, because the relative sliding friction between the solid and the tank wall is completely eliminated, the serious wear, tearing, local detachment, scratches, work hardening, and microcracks that would inevitably occur with traditional rigid sealing strips or scrapers during a lift of hundreds of meters are fundamentally solved. The surface quality and long-term corrosion resistance of the inner wall of the tank 100 are significantly protected.

[0049] Once the dome 200 rises to the design elevation or the preset stop position, the air supply system quickly cuts off the air supply to the isolation ring forming component 550, and simultaneously rapidly fills the air chamber 530 of the sealing component 520 with compressed air. The sealing component 520 completes radial expansion within seconds, and its outer surface reliably adheres to the tank wall and generates a certain clamping force, forming a mechanical + airtight composite seal. This creates a low-leakage and stable working environment for the subsequent welding of the dome 200 and the tank wall circumferential seam, avoiding the inefficient operation of repeated air replenishment and adjustment due to unstable airflow at the end of the traditional construction.

[0050] In one embodiment, the vents 540 of the sealing component 520 are arranged in staggered rows (e.g., two rows on the outside and one row on the inside). In the venting state, a small amount of gas still seeps out of the vents 540 toward the tank wall to form an auxiliary gas film, which further reduces the risk of instantaneous local leakage in the event of slight eccentricity.

[0051] The surface of the annular mounting position of the connecting ring 510 is pre-sandblasted and coated with a low-temperature wear-resistant undercoat. A low-temperature resistant silicone rubber buffer layer with a thickness of 1.5 to 3.0 mm is set between the inner side of the sealing component 520 and the mounting position to reduce the impact load on the weld of the connecting ring 510 during the inflation and deflation process and extend the fatigue life of the connecting ring 510.

[0052] This application transforms the traditional solid contact seal into a combination of "controllable gas filling and discharging elastic seal + dynamic gas ring isolation below". It achieves zero solid friction during the lifting process and can quickly restore a reliable mechanical seal after positioning. This significantly reduces the wear and tear of the sealing structure itself and irreversible damage to the tank wall while ensuring the airtightness of the construction. It provides higher quality consistency and longer service reliability for the gas lifting construction of the dome of large LNG cryogenic storage tanks.

[0053] In one embodiment, the sealing component 520 includes a wear-resistant layer 521, a tear-resistant layer 522, an airtight barrier layer 523, a buffer layer 524, and an air storage layer 525 sequentially arranged from the outside to the inside. The wear-resistant layer 521 is connected to the installation position, and the air cavity 530 is formed in the air storage layer 525. The air hole 540 passes through the wear-resistant layer 521, the tear-resistant layer 522, the airtight barrier layer 523, the buffer layer 524, and the air storage layer 525 sequentially from the outside to the inside.

[0054] Specifically, the sealing component 520 adopts a five-layer composite structure arranged sequentially from the outside to the inside, namely a wear-resistant layer 521, a tear-resistant layer 522, an airtight barrier layer 523, a buffer layer 524, and an air storage layer 525.

[0055] The wear-resistant layer 521 is located on the outermost layer and is directly connected to the annular mounting position of the connecting ring 510. The wear-resistant layer 521 is made of modified polytetrafluoroethylene (PTFE) reinforced composite sheet with a thickness of 4.5 to 6.5 mm, or ultra-high molecular weight polyethylene (UHMWPE) based wear-resistant material. Its inner edge is processed with inwardly protruding continuous locking lips or segmented protrusions. The locking lips / protrusions are embedded in the rectangular locking grooves 511 pre-processed on the outer periphery of the connecting ring 510 to achieve circumferential mechanical limiting and anti-detachment fixation. At the same time, an interference fit or auxiliary clamping strip of 0.5 to 1.2 mm is usually set between the wear-resistant layer 521 and the mounting position to ensure that the contact pressure between the outer surface and the inner wall of the tank 100 is uniform after inflation.

[0056] The second layer from the outside to the inside is the tear-resistant layer 522, which is made of high-strength aramid fiber fabric (such as Kevlar or Twaron, with a basis weight of 550–750 g / m²) or high-modulus polyethylene fiber fabric. After being laid in multiple oblique layers, it is bonded to the abrasion-resistant layer 521 at high temperature or co-vulcanized. This layer mainly bears circumferential tensile loads and prevents local tear propagation.

[0057] The third layer is an airtight barrier layer 523, which is composed of 2 to 4 layers of butyl rubber film and aluminum foil or aluminized polyester film alternately, with a total thickness of 1.8 to 3.2 mm. It is firmly bonded to the front and back layers through a high-temperature vulcanization process to ensure that the air cavity 530 is airtight for a long time.

[0058] The fourth layer is a buffer layer 524, which is made of closed-cell EPDM foam or neoprene rubber-based elastic foam material with a thickness of 6 to 10 mm (Shore hardness 25 to 45 A). This layer absorbs impact energy during radial compression and rebound, reducing direct compression on the inner gas storage layer 525.

[0059] The innermost layer is the gas storage layer 525, which is made of low-temperature resistant fluororubber (FKM) or hydrogenated nitrile rubber (HNBR) as the main material, with a thickness of 8 to 14 mm. The interior forms a continuous closed annular gas cavity 530 along the entire circumference. The gas cavity 530 is basically collapsed in the deflated state and can be uniformly expanded to the designed thickness in the inflated state.

[0060] The above five layers are bonded together as an integral annular sealing component 520 through stepwise high-temperature molding vulcanization or strong adhesive bonding. Multiple rows of micro-pores 540 are evenly distributed circumferentially on the outer surface of the sealing component 520 (i.e., the outer surface of the wear-resistant layer 521). All pores 540 radially penetrate the wear-resistant layer 521, tear-resistant layer 522, airtight barrier layer 523, buffer layer 524, and finally into the air cavity 530 inside the air storage layer 525, ensuring that the pore channels remain unobstructed even after multiple inflation and deflation cycles. The outer opening diameter of each pore 540 is typically controlled between 0.9 and 1.5 mm to reduce ineffective leakage during deflation and to form a micro-air film for auxiliary lubrication during inflation.

[0061] When compressed air is introduced into the air chamber 530 through the air pipe, the air storage layer 525 expands first and transmits pressure outward. The buffer layer 524 is compressed and the load is evenly distributed. The airtight barrier layer 523 keeps the air chamber 530 from leaking. The tear-resistant layer 522 restricts excessive overall deformation. The wear-resistant layer 521 generates a stable radial clamping force on the outer surface, so that the sealing component 520 can reliably abut against the inner wall of the tank 100 to form a sealing state.

[0062] When the air chamber 530 is released to near atmospheric pressure or slightly negative pressure, the air storage layer 525 elastically retracts, causing each layer to contract inward synchronously. A radial gap of 5 to 22 mm is quickly formed between the outer surface of the wear-resistant layer 521 and the inner wall of the tank 100. At this time, the sealing component 520 is in a state of disengagement and travel, working together with the lower isolation air ring forming component 550 to achieve a climbing process without solid friction.

[0063] When disengaged from the walking state (main lifting stage), the sealing component 520 retracts radially as a whole, and there is no contact load between it and the tank wall. Therefore, it completely eliminates the damage forms that traditional single-layer rubber or brush seals inevitably produce during long-distance relative sliding, such as surface abrasive wear, ploughing scratches, thermal accumulation softening, and tearing propagation. At the same time, the low friction coefficient material (typically friction coefficient 0.08 to 0.15) selected for the wear-resistant layer 521 will only produce very slight scratches even under occasional minor collisions, and will not form a deep damage source, effectively protecting the surface smoothness of the 9%Ni steel tank wall and the integrity of the subsequent anti-corrosion coating.

[0064] In the sealed state (after the dome 200 is in place), the wear-resistant layer 521 provides a durable high surface pressure contact surface, the tear-resistant layer 522 prevents the tearing and expansion of local high-pressure areas, the airtight barrier layer 523 ensures long-term airtightness, the buffer layer 524 absorbs the small displacements caused by welding vibration and temperature changes, and the gas storage layer 525 maintains stable elastic recovery force. The five layers work together to enable the sealing component 520 to achieve reliable circumferential airtight sealing under low working pressure, avoiding the problem of local plastic deformation or stress concentration of the tank wall caused by the excessive rigidity of traditional rigid sealing strips.

[0065] In one embodiment, the wear-resistant layer 521 is made of PTFE composite material filled with carbon fiber or glass microspheres, further reducing the coefficient of friction to below 0.06; the tear-resistant layer 522 adopts a bidirectional 45° oblique layup to improve the balance of circumferential and radial strength. The thickness of the buffer layer 524 is locally increased (by 2-4 mm in the corresponding connection area of ​​the lifting mechanism 600) to compensate for the uneven local compression caused by the self-weight of the arch 200, further extending the overall fatigue life of the sealing component 520.

[0066] This application adopts a multi-layered functional gradient composite structure from the outside to the inside, which rationally divides the functions of wear resistance, low friction, gas barrier, buffering, and gas storage. It achieves near-zero solid wear during the lifting stage and provides reliable airtight support during the positioning stage. This fundamentally solves the core problem in the background technology of "long-term friction between the sealing device and the tank wall causing damage to the sealing components and a decrease in the life of the tank wall", and provides higher reliability and economy for the gas lifting construction of large cryogenic storage tank domes.

[0067] In one embodiment, a circumferentially arranged groove 511 is formed on the connecting ring 510, and at least a portion of the wear-resistant layer 521 is engaged in the groove 511.

[0068] Specifically, a rectangular groove 511 is continuously machined along the entire circumference of the outer peripheral surface of the connecting ring 510, i.e., at the root of the annular mounting position. The groove 511 typically has a depth of 7.5–11.0 mm and a width of 10.0–14.5 mm. The bottom of the groove is concentric with the outer generatrix of the connecting ring 510, and the groove opening faces radially outward with a slight chamfer (0.5–1.2 mm × 45°) to facilitate the smooth insertion of the wear-resistant layer 521's retaining lip. The axial position of the groove 511 is located near the inner edge of the annular mounting position, approximately 18–28 mm from the outer edge of the mounting position.

[0069] The wear-resistant layer 521 is made of PTFE-based composite sheet or UHMWPE modified sheet with a thickness of 5.0–6.8 mm. One or more inwardly protruding continuous retaining lips are machined along its inner edge (i.e., the side closest to the connecting ring 510). The cross-sectional shape of the retaining lip basically matches the retaining groove 511. The thickness of the retaining lip is 0.3–0.8 mm less than the depth of the retaining groove 511, and the width is 0.4–1.0 mm less than the width of the retaining groove 511, forming a certain assembly gap to accommodate temperature changes and minor deformations. During assembly, the wear-resistant layer 521 is first slightly enlarged in inner diameter through radial compression or temperature difference (local heating to 60–80°C). Then, the retaining lip is aligned with the retaining groove 511 and pushed axially, so that the retaining lip is completely embedded inside the retaining groove 511. After the wear-resistant layer 521 cools or recovers, the retaining lip forms a reliable circumferential limiting and axial anti-disengagement structure within the retaining groove 511. At this time, the outer surface of the wear-resistant layer 521 still maintains a radial interference fit of 0.4 to 1.1 mm with the annular mounting position of the connecting ring 510, further improving the overall mounting rigidity.

[0070] When the sealing component 520 is in an inflated state, the gas storage layer 525 expands outward, sequentially pushing the buffer layer 524, the airtight barrier layer 523, and the tear-resistant layer 522, ultimately causing the outer surface of the wear-resistant layer 521 to abut against the inner wall of the tank body 100 with uniform surface pressure. At this time, the retaining lip is subjected to an outward tensile force in the retaining groove 511, but since the retaining lip is completely embedded in the groove and forms multi-point contact with the groove wall, the wear-resistant layer 521 will not experience circumferential slippage or axial movement. Even if there are local air pressure fluctuations or slight off-center loads during the lifting and lowering of the dome 200, the mechanical engagement between the retaining lip and the retaining groove 511 can still maintain the stable position of the wear-resistant layer 521.

[0071] When the sealing component 520 switches to the venting state (the air chamber 530 is close to atmospheric pressure or slightly negative pressure), the air storage layer 525 elastically retracts, and all layers contract inward synchronously. The outer surface of the wear-resistant layer 521 separates from the inner wall of the tank 100, and the radial gap returns to 8-24 mm. At this time, the retaining lip remains embedded in the retaining groove 511, and the wear-resistant layer 521 will not loosen or warp locally due to rebound force or construction vibration.

[0072] In this embodiment, the wear-resistant layer 521, as the outermost layer that directly contacts the tank wall, withstands repeated compression-release cycles in the abutment sealing state, and withstands the inward pulling force when the air chamber 530 retracts in the venting state. Traditional methods that rely solely on bonding or pressure plates for fixation are prone to problems such as fatigue peeling of the bonding interface, loosening of pressure plate bolts, or local warping after thousands of inflation and deflation cycles or drastic temperature changes (-165℃ to +50℃). This can lead to misalignment, tearing, or even complete detachment of the wear-resistant layer 521, thereby causing the sealing component 520 to fail or produce uneven adhesion during the next inflation. In this embodiment, a mechanical limiting method of continuous circumferential locking lip embedded in the locking groove 511 is adopted, which changes the fixation of the wear-resistant layer 521 from simple friction or adhesive constraint to geometric interlocking constraint. Even under extreme working conditions (such as local overpressure, strong vibration or material aging), the locking lip can still maintain a stable position by relying on the groove wall of the locking groove 511, avoiding any form of circumferential or axial displacement of the wear-resistant layer 521, thereby ensuring that the sealing component 520 maintains the designed working geometry throughout the entire construction cycle and the first few years of use.

[0073] Meanwhile, this snap-fit ​​method eliminates the need for additional pressure plates or a large number of bolts on the outer surface of the connecting ring 510, reducing the number of welds and fasteners, lowering the risk of stress concentration in the connecting ring 510 itself, and avoiding the construction safety hazards of bolts loosening or falling during high-altitude operations.

[0074] In one embodiment, the slot 511 is arranged in segments (each segment has an arc length of approximately 1.2–2.0 m, with a 2–4 ​​mm expansion joint between segments). The retaining lip is correspondingly segmented to better accommodate the circumferential thermal expansion and contraction differences between the connecting ring 510 and the wear-resistant layer 521 caused by temperature differences, further reducing the accumulation of internal stress during long-term use. The retaining lip has a trapezoidal or T-shaped cross-section with barbs, and the slot 511 is correspondingly processed into a matching inner-expanding groove shape, so that the retaining lip forms a one-way self-locking effect after being embedded, further improving the resistance to axial pull-out, which is suitable for ultra-large storage tanks (over 200,000 m³) with larger lifting capacities or longer construction periods.

[0075] This application, by setting a full-circumference groove 511 on the connecting ring 510 and reliably embedding the wear-resistant layer 521 lip, structurally eliminates the potential risks of loosening, misalignment, or local failure that are prone to occur in traditional fixing methods under repeated operation and temperature difference environments. This ensures the positional accuracy and functional stability of the wear-resistant layer 521 throughout the entire air jacking process and subsequent long-term service, ultimately significantly improving the overall reliability and service life of the sealing component 520.

[0076] In one embodiment, the isolation gas ring forming component 550 includes an integrally formed base ring 551, a first blocking ring 552 and a second blocking ring 553. The first blocking ring 552 is located above the second blocking ring 553. The gas ring forming chamber is formed between the base ring 551, the first blocking ring 552 and the second blocking ring 553. The gas ring forming chamber has an annular air passage disposed toward the inner wall of the tank 100.

[0077] Specifically, the isolation ring forming component 550 adopts an integrally formed structure, including a base ring 551, a first blocking ring 552 and a second blocking ring 553. All three are formed in one piece from the same 18-28 mm thick low-magnetic stainless steel sheet (e.g., 316L) through CNC bending, rolling and full penetration welding processes.

[0078] The base ring 551 is a horizontal ring plate, and its inner side is reliably fixed to the lower flange face of the connecting ring 510 by a group of high-strength bolts or continuous fillet welds. The outer diameter of the base ring 551 is slightly smaller than that of the connecting ring 510, and its radial width is typically 80–140 mm. The upper surface of the base ring 551 faces the sealing component 520, with an axial clearance of 10–30 mm, serving as a transition space for subsequent airflow rectification and pressure equalization.

[0079] The first blocking ring 552 is formed by vertically bending upward from the outer edge of the base ring 551. Its height is generally 45 to 75 mm. Its upper free end is slightly constricted inward towards the inner wall of the tank 100 (constriction angle 3° to 8°), forming the first axial barrier.

[0080] The second blocking ring 553 is located above the first blocking ring 552. It is bent upward from the middle of the base ring 551. Its height is usually 10 to 25 mm lower than that of the first blocking ring 552 (that is, the upper end of the second blocking ring 553 is lower than the upper end of the first blocking ring 552). Its free end also faces the inner wall of the tank 100, but the closing angle is slightly larger (6° to 12°), forming a second axial barrier.

[0081] The base ring 551, the first blocking ring 552, and the second blocking ring 553 together form a closed annular space with an approximately trapezoidal or rectangular cross-section, i.e., an air ring forming chamber. This chamber is connected to the air source system of the lifting mechanism 600 above the tank wall through one or more main air supply pipes of DN50 to DN80.

[0082] A continuous annular air passage is formed on the side of the gas ring forming chamber facing the inner wall of the tank 100 (i.e., radially outward). This annular air passage is defined by the gap between the upper free ends of the first blocking ring 552 and the second blocking ring 553. The outlet width of the air passage is typically controlled between 1.2 and 3.8 mm and is uniformly consistent along the entire circumference. In actual molding, the outlet width of the air passage can be finely adjusted (accuracy ±0.2 mm) by partially milling the upper end of the first blocking ring 552 or the second blocking ring 553 or by adding adjustable limiting shims to adapt to the airflow requirements of different tank diameters and different lifting stages.

[0083] When the sealing component 520 is in the venting state (i.e., radially contracted and detached from the tank wall), the gas supply system introduces high-pressure gas into the gas ring forming chamber. The gas first diffuses circumferentially and undergoes preliminary rectification within the chamber, and then is ejected at high speed from the narrow annular gas channel formed between the first blocking ring 552 and the second blocking ring 553 (exit velocity typically 80–180 m / s). Since the height of the first blocking ring 552 is higher than that of the second blocking ring 553, the ejected airflow exhibits an initial downward tilt (angle approximately 5°–18°). This airflow, along with the upward main airflow (velocity typically 0.8–3.5 m / s) provided by the gas pump 400 within the gas storage space 300, undergoes intense shearing, counter-current, and entrainment within the annular gap. This rapidly establishes a high-speed, continuous, and stable air curtain, i.e., an isolation gas ring, with a thickness of approximately 18–45 mm, encircling the entire circumference of the entire annular gap between the outer periphery of the dome 200 and the inner wall of the tank body 100.

[0084] In this embodiment, the isolation ring forming component 550 does not have any solid contact with the inner wall of the tank 100 during operation. The narrow slit outlet of the annular air passage maintains a constant radial gap (typically 12-32 mm) with the tank wall, completely eliminating the wear, tearing, and chipping of the seal itself caused by the continuous sliding friction between the traditional brush-type, scraper-type, or lip seal and the tank wall during a lift of hundreds of meters, as well as irreversible damage such as scratches, local cold work hardening, and microcrack initiation on the inner wall surface of 9% Ni steel.

[0085] Meanwhile, since the base ring 551, the first blocking ring 552, and the second blocking ring 553 are integrally formed, problems such as weld leakage, assembly misalignment, or thermal stress concentration that may occur when splicing multiple parts are avoided. The height difference and double-closing structure formed by the first blocking ring 552 and the second blocking ring 553 give the ejected airflow stronger downward deflection and axial rigidity. Even when the main airflow velocity fluctuates or the dome 200 is slightly tilted, the continuity and sealing of the air curtain can still be maintained, effectively preventing the rising gas from passing through the gap and entering the already raised area. Thus, excellent gas barrier performance is achieved without relying on solid seals, significantly reducing the ineffective power consumption of the air pump 400 and the total air consumption.

[0086] In one embodiment, a thin layer of low-temperature resistant PTFE with a thickness of 1.5 to 3.0 mm is added to the free end of the second blocking ring 553 facing the tank wall to further reduce the friction coefficient during occasional collisions and improve the erosion resistance of the air passage outlet. The annular air passage between the first blocking ring 552 and the second blocking ring 553 is divided into sub-air passages of different widths along the circumference (for example, locally widened to 4.0 to 5.5 mm at the installation position of the corresponding lifting mechanism 600) to compensate for the slight unevenness of local airflow caused by the space occupied by the lifting mechanism 600, and further improve the circumferential uniformity of the isolation air ring.

[0087] This application adopts an integrally molded base ring 551 + double blocking ring structure, which changes the formation of the isolation gas ring from relying on solid contact to a pure pneumatic high-speed air curtain method. While ensuring zero gas leakage during the lifting process, it fundamentally eliminates the double damage problem caused by long-term friction between the sealing component 520 and the tank wall. This provides higher construction quality consistency, tank surface integrity protection, and long-term service reliability for the gas lifting construction of the dome of large LNG cryogenic storage tanks.

[0088] In one embodiment, the first blocking ring 552 is located on one side of the gas ring forming chamber and is arranged radially downward, and the second blocking ring 553 is located on one side of the gas ring forming chamber and is arranged radially upward, so that the gas ring forming chamber gradually narrows radially.

[0089] Specifically, the gas ring forming chamber of the isolation gas ring forming component 550 has a radially tapering shape, which is achieved by the inclined arrangement of the first blocking ring 552 and the second blocking ring 553.

[0090] The first blocking ring 552 is located radially inner to the gas ring forming chamber (near the connecting ring 510), extending upward from the upper surface of the base ring 551. Its plate surface is radially inclined downward, with the inclination angle typically controlled between 8° and 18° (relative to the horizontal plane), causing the upper free end of the first blocking ring 552 to be offset radially outward (i.e. towards the inner wall of the tank 100) by 15 to 38 mm relative to its root. The plate thickness of the first blocking ring 552 is generally 10 to 16 mm, and the upper free end facing the tank wall can retain its original plate thickness or be locally thinned to 6 to 9 mm with rounded corners.

[0091] The second blocking ring 553 is located radially outside the gas ring forming chamber (near the inner wall of the tank 100), extending upward from the upper surface of the base ring 551. Its plate surface is radially inclined upward, with an inclination angle typically between 5° and 15° (relative to the horizontal plane), causing the upper free end of the second blocking ring 553 to be offset radially inward (i.e., towards the connecting ring 510) by 8 to 25 mm relative to its root. The plate thickness of the second blocking ring 553 is generally 8 to 14 mm, and its upper free end forms an annular gas passage outlet with a width of 1.0 to 3.5 mm between it and the upper free end of the first blocking ring 552.

[0092] Because the first blocking ring 552 is inclined downwards and outwards, and the second blocking ring 553 is inclined upwards and inwards, the distance between their upper ends continuously decreases from the root of the chamber (near the base ring 551, typically 80–130 mm wide) towards the outlet, thus giving the entire gas ring forming chamber a radially narrowing flow channel shape. In a typical embodiment, the cross-sectional area at the chamber root is approximately 2.8–5.5 times the cross-sectional area at the chamber outlet.

[0093] When the sealing component 520 is in the venting state and the isolation ring forming component 550 is in operation, the air supply system of the lifting mechanism 600 introduces compressed air into the ring forming chamber. The gas first enters the wider area at the root of the chamber, where it undergoes initial diffusion and pressure equalization on the upper surface of the base ring 551. Subsequently, guided by the downward-inclined wall of the first blocking ring 552, the airflow acquires outward and downward velocity components. Simultaneously, the upward-inclined wall of the second blocking ring 553 further compresses the flow channel cross-section, accelerating the gas velocity within the chamber from 20–45 m / s at the inlet to 80–220 m / s before the outlet. At the moment the gas is ejected through the narrow slit of the annular air passage, the Venturi effect caused by the rapid contraction of the flow channel significantly increases the outlet dynamic pressure, resulting in a high Reynolds number jet (Re>2×10⁻⁶). 5 The projectile is directed into the annular gap between the inner wall of the tank 100 and the outer periphery of the dome 200.

[0094] The ejected airflow has a significant downward tilt angle (the combined tilt angle is typically 12°–25°) due to the downward guidance of the first blocking ring 552. This jet undergoes intense shearing and collision with the rising main jacking airflow (velocity 0.9–3.8 m / s). The high-speed jet entrains surrounding low-speed gas, forming a continuous high-speed gas curtain layer with a thickness of approximately 20–50 mm. This gas curtain layer maintains a high degree of uniformity in the circumferential direction and exhibits a stable shape in the axial direction that gradually thins from the outer periphery towards the tank wall without interruption, thereby effectively blocking the channel for the main jacking gas to escape upward into the already raised area.

[0095] In this embodiment, traditional gas injection channels with uniform cross-sections or slight flaring have limited gas velocity enhancement and insufficient outlet jet flow. When the main airflow velocity fluctuates or the arch 200 is slightly deflected, the air curtain is prone to local thinning, breakage, or direct dispersion by the main airflow, leading to upward leakage of the lifting gas. This, in turn, causes unstable lifting speed of the arch 200, frequent gas replenishment by the air pump 400, and increased energy consumption. In contrast, this embodiment utilizes a gradually narrowing flow channel formed by the downward outward inclination of the first blocking ring 552 and the upward inclination of the second blocking ring 553. This allows the gas to achieve significant acceleration and directional control before ejection, resulting in a higher dynamic pressure and downward rigidity of the outlet jet. Even when the main airflow increases instantaneously by 30% to 50% or the arch 200 is horizontally deflected by ±15 mm, the air curtain can still maintain continuity and sealing, effectively controlling the upward leakage rate to within 5% of the design value. This significantly improves the pressure stability and construction efficiency of the lifting process.

[0096] Meanwhile, since the formation of the air curtain mainly relies on the shearing and momentum exchange of the high-speed jet rather than simple pressure blocking, the required air supply pressure and flow rate are reduced by about 25% to 40% compared with the traditional structure, which reduces the installed capacity and operating cost of the high-pressure air source system.

[0097] In one embodiment, the downward tilt angle of the first blocking ring 552 is locally varied (e.g., reduced to 6°–10° in the region below the corresponding lifting mechanism 600, and maintained at 14°–18° in other regions) to compensate for the local airflow asymmetry caused by the space occupied by the lifting mechanism 600, further improving the uniformity of the air curtain around the entire circumference. The upper 1 / 3 of the upward-tilted section of the second blocking ring 553 is provided with circumferentially spaced guide ribs (4–8 mm high, 150–300 mm spacing) to further rectify the airflow within the chamber and suppress the generation of local eddies, thereby improving the laminar flow rate and directional consistency of the outlet jet.

[0098] This application constructs a radially narrowing flow channel within the gas ring forming chamber by arranging the first blocking ring 552 and the second blocking ring 553 in opposite tilt directions. From a fluid dynamics perspective, this significantly enhances the anti-interference capability and stability of the isolation gas ring. Under the premise of completely avoiding solid contact friction, it achieves a gas barrier effect superior to traditional methods, providing higher process controllability, tank wall surface protection level, and overall economy for the gas jacking construction of large cryogenic storage tank domes.

[0099] In one embodiment, the diameter of the second blocking ring 553 is smaller than the diameter of the first blocking ring 552.

[0100] Specifically, the outer diameter of the upper free end of the first blocking ring 552 (i.e., the innermost boundary of the annular air passage) is usually the value obtained by subtracting the design clearance from the inner diameter of the tank body 100, denoted as D1. The outer diameter of the upper free end of the second blocking ring 553 is denoted as D2, and D2 < D1. The difference ΔD = D1 - D2 is generally controlled within 35 - 85 mm (corresponding to different tank diameter scales). This diameter difference is mainly reflected in the radial position relationship of the upper free ends of the two rings: the upper end of the first blocking ring 552 is located at a relatively outer position, while the upper end of the second blocking ring 553 significantly retracts radially inward, so that the radial center line of the annular air passage outlet is offset inward by about 18 - 42 mm relative to the upper end of the first blocking ring 552.

[0101] During the processing and forming, both the first blocking ring 552 and the second blocking ring 553 are bent upward from the base ring 551. However, the bending starting position of the second blocking ring 553 is closer to the inner side of the base ring 551 (radially inward by 20 - 55 mm), and the horizontal projection length of its upward inclined section is shorter, thus ensuring that the outer diameter of the upper free end of the second blocking ring 553 is always smaller than that of the upper free end of the first blocking ring 552. Even considering the material thickness, tolerance, and welding deformation, this diameter difference still remains within the design range (tolerance ±1.5 mm).

[0102] When compressed air with a pressure of 0.32 - 0.82 MPa is introduced into the air ring forming chamber by the air source, after the gas enters from the root of the chamber (with a larger width), it is first guided by the downward and outward inclined wall surface of the first blocking ring 552 to obtain the main velocity components of outward and downward directions. Subsequently, due to the obvious inward retraction of the second blocking ring 553 (i.e., smaller diameter), the flow passage is subjected to stronger radial compression in the last one-third region near the outlet, and the cross-sectional area further decreases sharply. When the gas passes through the inner side wall surface of the second blocking ring 553, it is forced to deflect inward, and at the same time, it is restricted outward by the outer side wall surface of the first blocking ring 552, and finally sprays out from the eccentric annular air passage formed between D2 and D1. At this time, the jet center line is no longer horizontal or simply downward along the radial direction, but shows an obvious synthetic direction of inward and downward (the synthetic inclination angle is usually 15° - 28°,偏向罐壁内侧).

[0103] The jet formed by this eccentric injection quickly entrains the surrounding static or low-speed gas after leaving the air passage, and constructs an eccentric but continuous high-speed air curtain in the annular gap between the outer periphery of the arch top 200 and the inner wall of the tank body 100. The thickness of this air curtain is thicker on the side close to the tank wall (about 28 - 55 mm), and relatively thinner on the side close to the outer edge of the arch top 200 (about 12 - 30 mm), showing a wedge-shaped profile that gradually thickens from the outside to the inside as a whole. Therefore, it has stronger anti-deflection ability under the action of the main upward lifting air flow (upward velocity 0.8 - 4.2 m / s).

[0104] In this embodiment, if the upper diameters of the two blocking rings are the same or the diameter of the second blocking ring 553 is larger, the center line of the jet at the outlet of the annular air passage tends to be radially symmetrical or deflected outward. When the high-speed airflow encounters the rising main airflow, it is easily lifted upward or blown outward, causing the air curtain to become thinner or even have local "windows" in the area near the tank wall. The main lifting gas can leak upward through these weak areas, causing fluctuations in the acceleration of the dome 200, local pressure buildup, or frequent start-stop of the air pump 400. In this embodiment, the inward contraction (smaller diameter) of the second blocking ring 553 causes the jet center line to actively deflect inward and downward. The main body of the air curtain is closer to the inner wall of the tank 100, exhibiting higher downward rigidity and coverage integrity under the impact of the main airflow. Even if the dome 200 experiences a horizontal offset of ±20 to 40 mm or the main airflow velocity increases instantaneously by more than 40%, the air curtain can still remain continuous and uninterrupted, effectively controlling the upward leakage rate at an extremely low level (usually <4% of the design value).

[0105] Meanwhile, the eccentric jet structure makes the effective blocking area of ​​the air curtain more concentrated in the high-risk leakage path near the tank wall, reducing the circumferential diffusion and dissipation of ineffective gas. The gas supply flow rate is reduced by about 18% to 35% compared with the symmetrical outlet structure, which reduces the load and operating energy consumption of the gas source system.

[0106] In one embodiment, the upper diameter of the second blocking ring 553 is significantly smaller than that of the first blocking ring 552 (ΔD reaches 70–110 mm), making it suitable for ultra-large storage tanks with long lift (>120 m) or large tank diameter (>100 m). In this case, the air curtain requires stronger downward rigidity to counteract the higher total momentum of the main airflow. A local annular extension lip (made of low-temperature resistant stainless steel or PTFE composite plate) with a thickness of 2.5–5.0 mm is added to the outer diameter of the upper end of the first blocking ring 552 to further increase the effective D1, while the second blocking ring 553 maintains its original diameter. This further enhances the inward deflection angle of the jet without changing the overall bending process, making it suitable for projects with extremely high airtightness requirements.

[0107] This application actively controls the centerline direction and momentum distribution of the annular gas channel outlet jet from a geometrical perspective by setting the upper diameter of the second blocking ring 553 to be smaller than the diameter of the first blocking ring 552. This allows the isolation gas ring to maintain excellent continuity, coverage, and anti-deflection capability even under complex flow field interference. Under the premise of completely avoiding any solid contact friction, it achieves a more efficient and stable blocking effect on the jacking gas, bringing higher process stability, tank wall protection level, and overall economy to the dome gas jacking construction of large cryogenic storage tanks.

[0108] In one embodiment, the lifting mechanism 600 includes: At least one guide rail 610 is vertically mounted on the inner wall of the tank 100; At least two sets of fixing seats 620 are distributed vertically at intervals at both ends of the guide rail 610, and all the fixing seats 620 are connected to the inner wall of the tank body 100. Slider 630, which slides in conjunction with the guide assembly; and... A lifting cylinder 640 is installed on the slider 630. The telescopic end of the lifting cylinder 640 is connected to the dome 200, and the lifting cylinder 640 is connected to the sealing mechanism 500 through a pipeline.

[0109] Specifically, the guide rail 610 is made of I-beams or rectangular hollow profiles (e.g., H200×200×8×12 or 150×100×6×8), and its length is determined according to the effective lift of the storage tank, usually the tank height plus a allowance (total length 18-28 m). Each guide rail 610 has 3-8 rails evenly arranged circumferentially along the inner wall of the tank body 100 (depending on the tank diameter), with its web facing the center of the tank body 100, and its flange surface fixed to the inner wall of the tank body 100 by continuous fillet welds or high-strength bolt groups. The upper surface of the guide rail 610 (i.e., the side facing the dome 200) is machined with precision linear guide rail 610 grooves or directly serves as the sliding surface of the slider 630, with a surface hardness ≥ HRC58 and a surface roughness Ra ≤ 0.4 μm.

[0110] The fixing base 620 is a steel plate assembly with a thickness of 20-40 mm. Each set of fixing bases 620 includes an upper fixing base 620 and a lower fixing base 620, which are welded or bolted to the top and bottom of the guide rail 610, respectively. The outer side plates of all fixing bases 620 are reliably fixed to the inner wall of the tank body 100 by double-sided full penetration fillet welds or M30-M48 high-strength bolt groups (preload controlled at 85%-95% of the design value), ensuring that the guide rail 610 remains vertical and without overall displacement throughout the jacking process.

[0111] The slider 630 adopts a four-sided enclosed structure, with an inner groove or roller assembly (typically 4 to 8 high-precision rollers or linear guide rail 610 slider 630) matching the guide rail 610. The radial clearance between the slider 630 and the guide rail 610 is controlled at 0.15 to 0.40 mm, and the axial clearance is ≤0.25 mm. The main body of the slider 630 is made of low-alloy high-strength steel, and the outer surface is partially inlaid with low-temperature resistant self-lubricating bushings (such as bronze matrix composite material filled with PTFE), ensuring low-friction, maintenance-free long-term sliding within a temperature range of -165℃ to +50℃.

[0112] The lifting cylinder 640 is a double-acting piston cylinder with a diameter typically ranging from φ320 to φ560 mm. Its stroke matches the single lifting height (generally 1.2 to 2.8 m). The cylinder body is hinged to the upper end face of the slider 630 via a high-strength pin or flange. The extended end of the cylinder piston rod is connected to the connecting lug plate on the outer edge of the dome 200 via a ball joint or universal joint, enabling force transmission and angle self-adaptation. The inlet / outlet ports of the lifting cylinder 640 are connected in parallel to the air supply system of the sealing mechanism 500 (especially the gas ring forming chamber and the gas storage layer 525) via low-temperature resistant high-pressure hoses. A one-way throttle valve and a pressure sensor are installed on the hoses to ensure synchronous coordination between the cylinder's movement and the charging / discharging process of the sealing component 520.

[0113] During the lifting operation of the dome 200, compressed air is first simultaneously introduced into the rod chambers (rodless chambers) of all lifting cylinders 640, causing the piston rods to extend synchronously and push the dome 200 upward. Simultaneously, the air chamber 530 of the sealing component 520 is simultaneously inflated, ensuring that the outer surface of the wear-resistant layer 521 adheres tightly to the inner wall of the tank body 100 and forms an effective seal. At the same time, the air supply system of the isolation ring forming component 550 is activated, establishing a high-speed isolation ring in the gap between the outer periphery of the dome 200 and the tank wall, preventing upward leakage of the lifting gas. Meanwhile, the slider 630 slides upward along the guide rail 610, which provides high-precision vertical guidance throughout the entire lifting process, ensuring that the dome 200 does not tilt or twist during the entire lifting stroke.

[0114] When a single stroke ends, the control system cuts off the air supply to the rod chamber and vents air to the rodless chamber (or through venting), the piston rod retracts, and the slider 630 descends along the guide rail 610 to the next set of fixed seats 620; then the above inflation-lifting-venting-return cycle is repeated until the dome 200 is raised to the design height.

[0115] In this embodiment, traditional jacking methods often employ a dispersed arrangement of multiple manual jacks or chain hoists, with guidance entirely dependent on temporary steel platforms or temporary welded components on the tank wall. This easily leads to problems such as arch 200 tilting, localized stress concentration, and accumulated synchronization errors. In severe cases, it can cause partial detachment of the sealing component 520, air curtain breakage, or structural instability of the arch 200. In contrast, this embodiment uses a combination of a vertical precision guide rail 610 fixed to the inner wall of the tank 100 and a multi-point synchronous cylinder. The guide rail 610 provides rigid vertical constraint throughout the entire process, and the minute gap between the slider 630 and the guide rail 610 ensures that the horizontal offset of the arch 200 is controlled within ±8 mm during the lifting stroke, significantly improving the directional stability and overall synchronization of the jacking process.

[0116] Meanwhile, the air supply pipeline of the lifting cylinder 640 and the air source system of the sealing mechanism 500 are connected in parallel and share the same system, so that the lifting action and the charging and discharging of the sealing component 520 and the establishment of the isolation air ring are strictly linked in sequence. This avoids the phenomenon of large gas leakage or premature seal failure caused by the asynchronous lifting and sealing in the traditional method. In actual construction, the total air consumption is reduced by about 30% to 45% compared with the decentralized lifting method, and the installed capacity and running time of the air pump 400 are optimized.

[0117] In one embodiment, two sets of independent sliders 630 (one on top and one on the bottom) are installed on each guide rail 610. Each set of sliders 630 is connected to a lifting cylinder 640, forming a "dual-cylinder parallel, dual-guide" structure, which further improves the single-point load-bearing capacity and anti-eccentric load capacity, and is suitable for ultra-large storage tanks with a lifting height exceeding 100 m or a large self-weight of the dome 200. A stroke sensor and displacement synchronization control module are added to the piston rod end connection of the lifting cylinder 640. The displacement of each cylinder is collected in real time by the PLC and the air intake flow of each cylinder is automatically adjusted to achieve high-precision synchronization with a lifting deviation of <±5 mm, which is suitable for projects with extremely high requirements for the geometric accuracy of the dome 200.

[0118] This application fundamentally solves the risks of low guiding accuracy, poor synchronization, low gas utilization, and local structural damage in traditional gas jacking construction by rigidly fixing and precisely guiding the lifting mechanism 600 to the inner wall of the tank 100, and linking it with the gas source system of the sealing mechanism 500. This provides higher process controllability, construction safety, tank 100 integrity protection level, and comprehensive economy for the overall jacking of the dome of large cryogenic storage tanks.

[0119] In one embodiment, the guide rail 610 has vertically spaced abutment grooves 650, and the slider 630 is rotatably provided with an abutment block 660, which can abut against any of the abutment grooves 650.

[0120] Specifically, multiple sets of abutment grooves 650 are machined at equal vertical intervals on both sides (or one side) of the web of the guide rail 610. The vertical spacing of each set of abutment grooves 650 matches the single stroke height of the lifting cylinder 640 (usually 1.2–2.8 m). The abutment grooves 650 have rectangular or trapezoidal cross sections, with a groove depth of generally 18–32 mm and a groove width of 80–140 mm. The bottom surface of the groove is machined with rounded corners (R5–R12 mm) to avoid stress concentration. The upper end face (i.e., the bearing surface) of the abutment groove 650 has an angle of 0°–3° with the horizontal plane (slightly inclined inward), while the lower end face is inclined at 45°–60° to facilitate the entry and exit of the abutment block 660.

[0121] The slider 630 has mounting ears on its side, and the abutment block 660 is hinged to the ears via a high-strength pin (diameter φ50~φ80 mm, material 40Cr quenched and tempered). The abutment block 660 is a steel block with a thickness of 30~50 mm. Its lower end is machined into a flat bearing surface that matches the upper end surface of the abutment groove 650, and its upper end has a sloping guide section (sloping angle 50°~70°) to facilitate automatic sliding into the next set of abutment grooves 650 when the slider 630 descends. The center of gravity of the abutment block 660 is biased towards the bearing surface, and it naturally maintains a downward hanging state under the action of gravity (natural hanging angle 80°~90°). A torsion spring (torque 15~35 N·m) is installed between the abutment block 660 and the ear plate to ensure that the abutment block 660 always maintains a pre-tension tendency towards the abutment groove 650 when no external force is applied.

[0122] When the arch 200 completes a single lifting operation and needs to return to its original position, the control system first cuts off the air supply to the rod chamber of the lifting cylinder 640 and introduces low-pressure gas into the rodless chamber (or slowly exhausts gas through a one-way throttle valve), causing the piston rod to slowly retract. At this time, the slider 630 moves downward along the guide rail 610, and the lower inclined surface of the abutment block 660 first contacts the upper inclined surface of the next set of abutment grooves 650. Under the combined action of gravity, the preload of the torsion spring, and the weight of the slider 630, the abutment block 660 rotates clockwise around the pin (rotating approximately 70° to 85° inward from its natural hanging position), and its lower bearing surface is completely embedded in the abutment groove 650, reliably fitting against the upper surface of the abutment groove 650. At this time, a rigid contact is formed between the bearing surface of the abutment block 660 and the bottom surface of the groove, and the slider 630 is reliably locked in its current position, unable to continue descending.

[0123] Subsequently, the piston rod of the lifting cylinder 640 continues to retract to its fully retracted state. Its entire weight, along with part of the weight of the arch 200, is transferred to the tank 100 structure via the slider 630 → abutment block 660 → abutment groove 650 → guide rail 610 → fixed seat 620 → inner wall of the tank 100, avoiding the risk of the piston rod bending or becoming unstable due to long-term pressure. Before the next lifting cycle begins, the control system introduces high-pressure gas into the rod chamber of the lifting cylinder 640. The piston rod extends, pushing the arch 200 upwards. Simultaneously, the slider 630 moves upwards, and the lower bearing surface of the abutment block 660 disengages from the upper surface of the abutment groove 650. Under the action of the torsion spring and gravity, the abutment block 660 quickly returns to its natural suspended state, preparing for the next return.

[0124] In this embodiment, during the return process of a traditional cylinder lifting mechanism, the slider 630 relies entirely on the tension or friction of the cylinder piston rod for positioning. This easily leads to problems such as the slider 630 sliding along the guide rail 610, accumulated positioning deviation, and bending deformation of the piston rod due to long-term axial pressure. In extreme cases, cylinder instability or fatigue cracking of local welds may even occur. However, this embodiment utilizes the pre-set abutment groove 650 on the guide rail 610 and the abutment block 660 on the slider 630 that can automatically engage / disengage. After the return is completed, a rigid mechanical lock is formed, and the slider 630 is completely constrained at a fixed height position, completely eliminating the risk of the slider 630 sliding down. The reliable fit between the bearing surface of the abutment block 660 and the upper end surface of the abutment groove 650 ensures that the cylinder piston rod only bears tension (or virtually no axial force) after retracting into position. This effectively avoids the phenomenon of piston rod instability due to long-term pressure, significantly improving the service life of the cylinder and the overall reliability of the system.

[0125] Meanwhile, this structure eliminates the need for complex hydraulic locking or mechanical pin devices during the return process. The action relies entirely on gravity, torsion springs, and inclined plane guidance to achieve adaptive embedding. The structure is simple, the action is reliable, and the system complexity and maintenance workload are reduced.

[0126] In one embodiment, a wear-resistant insert (made of high-hardness wear-resistant steel or nitrided alloy steel, hardness ≥ HRC62) with a thickness of 8-15 mm is added to the upper end face of each set of abutment grooves 650. A wear-resistant liner is correspondingly inlaid on the bearing surface of the abutment block 660, further extending the service life of the abutment parts. This is suitable for long-term construction projects with more than 500 lifting cycles. An auxiliary reset cylinder (cylinder diameter φ40-φ63 mm) driven by pneumatic or electric power is added to the abutment block 660. In cases requiring rapid return or under extreme conditions, the control system can actively drive the abutment block 660 to rotate and reset, further improving the action response speed and reliability.

[0127] This application achieves reliable mechanical positioning of the slider 630 and optimizes the force state of the cylinder piston rod during the lifting and return phase by setting vertically spaced abutment grooves 650 on the guide rail 610 and configuring rotatably embedded abutment blocks 660 on the slider 630. This fundamentally solves the technical problems of inaccurate positioning, easy instability of the piston rod, and poor system reliability in traditional structures, and provides higher construction safety, equipment durability, and process controllability for the gas lifting construction of large cryogenic storage tank domes.

[0128] Based on the same technical concept, in a second aspect, the present invention also proposes a method for gas jacking construction of a cryogenic storage tank, applying the cryogenic storage tank gas jacking sealing device described in the first aspect, the construction method comprising the following steps: S100. Install the sealing mechanism on the outer periphery of the already constructed dome; S200: The first gas flow is ejected into the gas storage space at a preset speed through the sealing mechanism; S300, A second airflow is ejected into the gas storage space via the air pump; S400, When the first airflow converges with the first airflow at the preset speed, the isolation air ring is formed; S500, Continue to pump the second airflow into the gas storage space through the air pump to push the dome up along the inner wall of the tank and carry out air jacking construction.

[0129] Specifically, the base ring of the sealing mechanism is reliably connected to the outer edge steel structure of the arch using high-strength bolts or intermittent fillet welds; the outer surface of the wear-resistant layer faces the inner wall of the tank, with a pre-designed gap (usually 35-65 mm) between it and the inner wall of the tank in the initial state; the isolation air ring forming components (including the first blocking ring, the second blocking ring, the connecting ring, etc.) are located above the base ring, and its annular air passage outlet is directly opposite the annular gap between the outer periphery of the arch and the inner wall of the tank; multiple guide rails of the lifting mechanism have been pre-welded and fixed vertically along the inner wall of the tank, and the slider and lifting cylinder have been installed and hinged to the connecting ear plate of the arch; all air lines (including the air supply pipe of the air ring forming chamber, the air supply pipe of the lifting cylinder, and the air filling pipe of the wear-resistant layer air chamber) have been connected in parallel with the ground air source station and the air tightness test has been completed.

[0130] Next, the first gas flow is ejected into the gas storage space (i.e., the closed gas chamber below the dome) at a preset speed through the sealing mechanism. The control system first activates the independent gas supply branch of the gas ring forming component, introducing dry compressed air into the gas ring forming chamber. After entering through the root of the chamber, the gas is constrained by the downward outward incline of the first blocking ring and the upward incline of the second blocking ring, continuously accelerating within the narrow flow channel, and ejected at the narrow slit of the annular gas channel in the form of a high-speed jet of 80–260 m / s. Because the diameter of the second blocking ring is smaller than that of the first blocking ring, the ejected gas flow has a significant inward and downward deflection (combined tilt angle 14°–30°), and quickly entrains the surrounding gas in the gap between the outer periphery of the dome and the inner wall of the tank, forming a high-speed isolation gas ring with a thickness of about 18–55 mm that continuously wraps around the outer edge of the dome. At this time, the first gas flow has not yet merged with the main rising gas flow (second gas flow) on a large scale. The isolation gas ring mainly serves to pre-establish an air curtain barrier and prevent the subsequent main gas flow from directly leaking upward.

[0131] Subsequently, a second airflow (the main jacking airflow) is injected into the gas storage space at a controlled flow rate using an air pump. The air pump outlet pressure is typically stabilized between 0.018 and 0.085 MPa (adjusted in real time depending on the lift and the weight of the vault). The gas enters the air chamber below the vault via the main ground pipeline, the distribution manifold on the vault, and multiple evenly distributed short intake pipes. During the intake process, the control system maintains a slow, linear increase in the flow rate of the second airflow (typically an initial flow rate of 15% to 25% of the maximum design flow rate), causing the pressure in the air chamber below the vault to rise steadily at a rate of 0.3 to 1.2 kPa / min.

[0132] When the first airflow (isolation ring jet) meets the second airflow (main rising airflow) at a preset velocity at the annular gap on the outer periphery of the arch, the isolation ring is formally formed and stabilized. The high-speed first airflow and the low-speed rising second airflow undergo intense shearing and momentum exchange. The second airflow is strongly suppressed and redistributed by the downward-deflected first airflow. Most of the gas is confined within the air chamber below the arch, continuing to accumulate pressure, with only a very small amount able to escape upwards through the air curtain. At this point, using multi-point pressure sensors and flow field monitoring probes installed on the outer edge of the arch, it can be confirmed that the isolation ring has formed a continuous, closed high-speed air curtain layer, with the upward leakage rate typically stable within 0.8% to 3.5% of the total intake volume.

[0133] A second airflow is continuously pumped into the gas storage space using an air pump, propelling the dome upwards along the inner wall of the tank to complete the air jacking operation. As the pressure in the air chamber continues to rise (typically at a rate of 0.8–2.5 kPa / min), the net upward force on the dome gradually exceeds its own weight and frictional resistance, and the dome begins to rise at a constant speed along the guide rail constraint direction (the rising speed is typically controlled between 18 and 65 mm / min). Throughout the entire rising process, the isolation air ring forming component continuously supplies air to maintain the stability of the air curtain; the lifting cylinder extends synchronously and provides auxiliary lifting force (accounting for 20%–45% of the total lifting force), while the vertical guiding accuracy and synchronicity of the dome are ensured throughout the lifting stroke via the guide rail, slider, and abutment block structure; the wear-resistant layer air chamber maintains a slightly positive pressure state to ensure stable low-friction sliding contact between the outer surface of the wear-resistant layer and the inner wall of the tank. After the lifting reaches the end of a single cylinder stroke, the system sequentially performs the following cyclical steps: cylinder retraction, slider abutment block locking into the next set of abutment grooves, slow depressurization of the air chamber to a safe value, and readjustment of air supply distribution, until the arch rises to the design height.

[0134] In this embodiment, traditional air-jacking construction often uses a single air source to perform both jacking and sealing functions. The formation of the isolation air curtain is delayed or unstable, and the main airflow can easily penetrate directly upwards into the already lifted area, resulting in a large amount of gas waste, violent fluctuations in the arch's lifting speed, local pressure buildup, and even structural instability. In contrast, this method separates and independently controls the first airflow (high-speed isolation air ring) and the second airflow (main jacking airflow), and establishes a stable high-speed air curtain in advance before the jacking begins. This effectively confines the main airflow to the enclosed space below the arch throughout the entire lifting process, reducing the upward leakage rate by 70% to 90% or more compared to traditional methods, and significantly improving gas utilization and lifting speed stability.

[0135] Meanwhile, by coordinating the rigid guidance of the lifting and sealing mechanisms with the air circuit, the horizontal offset within the arch lifting stroke is controlled within ±10 mm, and the lifting speed fluctuation is <±12%. This avoids common problems in traditional construction such as skew accumulation, sealing failure, and tank wall scratches, significantly shortening the construction cycle (the time for a single lifting cycle is reduced by 25% to 40% compared to the traditional method), and effectively protecting the anti-corrosion coating and geometric accuracy of the tank's inner wall.

[0136] In one embodiment, for large storage tanks with a diameter greater than 90 m or a lift exceeding 110 m, the first gas supply pressure is increased to 0.65–1.05 MPa, and the preset injection velocity is increased to 180–320 m / s to enhance the air curtain's ability to suppress the high-momentum main gas flow. Simultaneously, the initial pressurization rate of the second gas flow is reduced to 0.4–0.9 kPa / min to further improve the smoothness of the lift. During the last 20%–30% of the arch lift, the first gas flow rate is appropriately reduced (to 60%–75% of the normal value), while the second gas flow rate is increased. This slightly thins the air curtain thickness while maintaining continuity, reducing the total gas consumption during the final stage of construction while still reliably preventing leakage.

[0137] This application fundamentally solves the core technical problems of serious gas leakage, difficult lifting speed control, high construction risk, and low efficiency in traditional gas lifting construction by strictly separating and coordinating the establishment of the isolation gas ring with the supply of the main lifting airflow in terms of time and gas path, combined with the organic cooperation of the precision guiding lifting mechanism and the multi-layer sealing structure. It provides higher process stability, gas economy, construction safety and engineering quality assurance for the overall gas lifting of large cryogenic storage tank domes.

[0138] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the protection scope of the present invention.

Claims

1. A cryogenic storage tank gas lifting and sealing device, the cryogenic storage tank comprising a tank body and an arch formed within the tank body, the arch located at the bottom of the tank body, a gas storage space for storing lifting gas formed between the arch and the tank body, the gas storage space being connected to a gas pump, the gas pump being capable of pumping gas into the gas storage space to lift the arch from the bottom of the tank body to the top of the tank body, thereby enclosing the arch with the tank body to form the cryogenic storage tank, characterized in that... The air-lift sealing device includes: A sealing mechanism is provided around the outer periphery of the dome. The sealing mechanism has a sealing contact state and a disengaged, mobile state. In the sealing contact state, the sealing mechanism abuts against the inner wall of the tank, causing the dome to suspend within the tank. In the disengaged, mobile state, the sealing mechanism ejects a gas flow towards the gas storage space to counteract the gas flow within the gas storage space and form an insulating gas ring. Multiple lifting mechanisms are distributed circumferentially on the inner wall of the tank. All lifting mechanisms are located above the dome and connected to the dome. All lifting mechanisms can drive the dome to climb along the inner wall of the tank when the sealing mechanism is in the disengaged walking state, and can also suspend the dome inside the tank when the sealing mechanism is in the sealed state.

2. The cryogenic storage tank gas lifting sealing device as described in claim 1, characterized in that, The sealing mechanism includes: A connecting ring is provided around the outer periphery of the arch, and an annular mounting position is formed on the connecting ring around its outer periphery; A sealing component is installed at the mounting position and surrounds the outer periphery of the connecting ring. An air cavity is formed within the sealing component, and multiple air holes, each communicating with the air cavity, are formed on the sealing component at circumferential intervals. Each air hole is connected to the lifting mechanism via an air pipe, allowing the air cavity to switch between an inflated and deflated state. When the air cavity is in the inflated state, the sealing component abuts against the inner wall of the tank to form a sealing contact. An isolation ring forming component is installed on the connecting ring and is located below the sealing component. An air ring forming chamber is formed inside the isolation ring forming component and is connected to the lifting mechanism through a pipe. The isolation ring forming component can eject airflow from the ring forming chamber and form the isolation ring when the sealing component is in the venting state.

3. The cryogenic storage tank gas lifting and sealing device as described in claim 2, characterized in that, The sealing component includes a wear-resistant layer, a tear-resistant layer, an airtight barrier layer, a buffer layer, and an air storage layer, which are sequentially arranged from the outside to the inside. The wear-resistant layer is connected to the installation position, and the air storage layer forms the air cavity. The air hole passes through the wear-resistant layer, the tear-resistant layer, the airtight barrier layer, the buffer layer, and the air storage layer sequentially from the outside to the inside.

4. The cryogenic storage tank gas lifting sealing device as described in claim 3, characterized in that, The connecting ring has a circumferentially arranged groove, and at least a portion of the wear-resistant layer is engaged in the groove.

5. The cryogenic storage tank gas lifting sealing device as described in claim 4, characterized in that, The isolation gas ring forming component includes an integrally formed base ring, a first blocking ring, and a second blocking ring. The first blocking ring is located above the second blocking ring. The gas ring forming chamber is formed between the base ring, the first blocking ring, and the second blocking ring. The gas ring forming chamber has an annular air passage that faces the inner wall of the tank.

6. The cryogenic storage tank gas lifting sealing device as described in claim 5, characterized in that, The first blocking ring is located on one side of the gas ring forming chamber and is arranged radially downward, while the second blocking ring is located on one side of the gas ring forming chamber and is arranged radially upward, so that the gas ring forming chamber gradually narrows radially.

7. The cryogenic storage tank gas lifting sealing device as described in claim 6, characterized in that, The diameter of the second blocking ring is smaller than the diameter of the first blocking ring.

8. The cryogenic storage tank gas lifting sealing device as described in any one of claims 1 to 7, characterized in that, The lifting mechanism includes: At least one guide rail is vertically mounted on the inner wall of the tank. At least two sets of fixing seats are provided, which are distributed vertically at intervals at both ends of the guide rail, and all the fixing seats are connected to the inner wall of the tank. A slider, which slides in conjunction with the guide assembly; and... A lifting cylinder is installed on the slider, the telescopic end of the lifting cylinder is connected to the arch, and the lifting cylinder is connected to the sealing mechanism through a pipeline.

9. The cryogenic storage tank gas lifting sealing device as described in claim 8, characterized in that, The guide rail has vertically spaced abutment grooves, and the slider is also rotatably provided with abutment blocks, which can abut against any of the abutment grooves.

10. A method for gas jacking construction of a cryogenic storage tank, characterized in that, The construction method of using the cryogenic storage tank gas lifting sealing device as described in any one of claims 1 to 9 includes the following steps: The sealing mechanism is installed on the outer periphery of the already constructed dome; The sealing mechanism ejects a first gas flow into the gas storage space at a preset speed. A second airflow is ejected into the gas storage space via the air pump; When the first airflow converges with the first airflow at the preset speed, the isolation air ring is formed; The second airflow continues to be pumped into the gas storage space through the air pump to push the dome up along the inner wall of the tank and carry out air jacking construction.

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