Compressed air energy storage underground cavern with serial rubber air storage bags

Abstract

The compressed air energy storage underground cavern comprises a cavern lining, the tandem type rubber air storage bags, a separation wall and a drainage system, the cavern lining is arranged in surrounding rock, a cavern sealing door and an air inlet and outlet pipe are arranged on one side of the cavern lining, the air inlet and outlet pipe is communicated with the tandem type rubber air storage bags, and the drainage system is arranged in the cavern lining. The tandem type rubber air storage bag is arranged in the cavern lining and is formed by sequentially connecting a plurality of rubber bags in series in the longitudinal direction of the cavern lining, each rubber bag is integrally formed, the upper half portion of each rubber bag is tightly attached and fixed to the wall face of the cavern lining through a fixing device, and the lower half portion of each rubber bag naturally droops. Every two adjacent rubber bags are communicated through a flange and provided with a separation wall, the separation walls and the cavern lining are integrally arranged in the transverse direction of the cavern lining, the flanges are installed in the separation walls in an embedded mode, and the drainage system is arranged at the bottom of the cavern lining. The compressed air energy storage underground cavern is convenient to construct and operate, good in installation effect and air tightness, low in maintenance and repair cost and long in operation period.

Description

Technical Field

[0001] The present invention relates to the technical field of underground gas storage, and particularly relates to a compressed air energy storage underground chamber with a series-connected rubber air storage bag. Background Art

[0002] Compressed air energy storage (i.e., compressed air energy storage) is known as the air "power bank" and has the advantages of large energy storage capacity, long energy storage cycle, and small unit investment. It is considered to be one of the large-scale energy storage technologies with the broadest development prospects. The compressed air energy storage technology uses high-pressure air as a medium to achieve the storage and release of energy in the power grid. By reasonably regulating the storage and release of energy, intermittent energy sources such as wind power and photovoltaic power are converted into stable and controllable high-quality energy. Among them, the underground chamber, as a storage container for high-pressure air, plays an important role in the operation of a compressed air energy storage power station, and the key issue in its construction is the sealing problem of the underground chamber.

[0003] The invention with the application number 202110665113.3 and the name of "Compressed Air Energy Storage Lined Chamber Sealed with an Integral Rubber Bag" disclosed on November 18, 2022, discloses an integral rubber bag-sealed chamber. This compressed air energy storage chamber adopts a structure in which an integral rubber bag is installed inside a reinforced concrete lining in combination with a drainage ditch. This invention provides a new idea for the sealing of compressed air energy storage chambers. Flexible materials such as rubber have the advantages of good airtightness, being able to deform uniformly with the lining structure, and effectively transferring loads to the surrounding rock. However, the structure of underground gas storage chambers is generally large in volume, ranging from tens of thousands of cubic meters to hundreds of thousands of cubic meters. The corresponding integral rubber bag structure will have the characteristics of large weight, large volume, difficult transportation, and difficult installation. It is difficult to realize the integral rubber air storage bag in the actual construction of compressed air energy storage chambers. And the rubber air storage bag formed by piecing and pasting has the disadvantages of numerous splicing seams, long construction period, inability to guarantee construction quality, inability to guarantee the service life of glue, etc., and there is also a risk of air leakage. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a compressed air energy storage underground chamber with a series-connected rubber air storage bag in view of the deficiencies of the prior art. This compressed air energy storage underground chamber is convenient for construction operation, has good installation effect and airtightness, low maintenance and repair costs, and a long operation cycle.

[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows: A compressed air energy storage underground chamber with a series-connected rubber airbag includes an inner lining of the chamber, a series-connected rubber airbag, a partition wall, and a drainage system. The inner lining of the chamber is arranged in the surrounding rock. One side of the inner lining of the chamber is provided with a chamber sealing door and an air inlet and outlet pipe. The air inlet and outlet pipe is communicated with the series-connected rubber airbag. The series-connected rubber airbag is arranged in the inner lining of the chamber. The series-connected rubber airbag is formed by sequentially connecting a plurality of rubber bags in series along the longitudinal direction of the inner lining of the chamber. Each rubber bag is integrally formed. The upper half of each rubber bag is closely fixed to the wall surface of the inner lining of the chamber through a fixing device. The lower half of each rubber bag naturally hangs down. Adjacent rubber bags are communicated through a flange. A partition wall is arranged between adjacent rubber bags. The partition wall is integrally arranged with the inner lining of the chamber along the transverse direction of the inner lining of the chamber. The flange is embedded and installed in the partition wall. The drainage system is arranged at the bottom of the inner lining of the chamber.

[0006] The working principle of the compressed air energy storage underground chamber with a series-connected rubber airbag of the present invention: Under the inflation condition, the series-connected rubber airbag closely adheres to the wall surface of the inner lining of the chamber, and transmits the internal pressure to the surrounding rock through the inner lining of the chamber. The reaction of the surrounding rock makes the internal and external pressures of the series-connected rubber airbag reach equilibrium, and seals the compressed air energy storage underground chamber. Under the deflation condition, the upper half of each rubber bag closely adheres to the wall surface of the inner lining of the chamber, and the lower half of each rubber bag is separated from the wall surface of the inner lining of the chamber and is in an unconstrained state of natural hanging, ensuring the overall shape of the series-connected rubber airbag and avoiding adhesion, uneven expansion or contraction of the series-connected rubber airbag caused by repeated inflation and deflation.

[0007] Under the inflation and deflation conditions, the condensate water in the compressed air energy storage underground chamber and the groundwater seeping into the compressed air energy storage underground chamber can freely drain out of the chamber through the drainage system, and the overall shape of the series-connected rubber airbag basically remains unchanged.

[0008] The compressed air energy storage underground chamber of the present invention adopts a series-connected rubber air storage bag formed by sequentially connecting multiple rubber bags in series. Adjacent rubber bags are connected through flanges. The upper half of each rubber bag is closely fixed to the wall surface of the chamber lining through a fixing device, and the lower half hangs naturally. The weight of a single rubber bag is light and the volume is small, the construction operation is convenient, the installation effect is good, and the series-connected rubber air storage bag has few interfaces and good air tightness. In addition, the flange is embedded and installed in the partition wall, and the partition wall supports the flange and the side wall of the rubber bag, which can ensure uniform stress on the rubber bag, prevent the rubber bag from being torn, and avoid adhesion of the side walls of adjacent rubber bags, preventing non-uniform expansion of the rubber bag and ensuring the use effect and service life of the series-connected rubber air storage bag. The maintenance and repair costs of the compressed air energy storage underground chamber of the present invention are low. If local air leakage of a rubber bag is found, local repair or overall replacement can be adopted for the leaking rubber bag. The rubber bag is convenient to replace, the operation is simple and the cost is low, and there is no need to replace the entire series-connected rubber air storage bag.

[0009] Each rubber bag is integrally formed with good sealing effect, which can avoid construction quality problems and air leakage problems caused by splicing of sealing materials in general compressed air energy storage underground chambers.

[0010] The length and quantity of the rubber bags can be flexibly adjusted according to the size of the compressed air energy storage underground chamber, and the diameter of the rubber bag is determined according to the requirements of the project site. The size, thickness and weight of a single rubber bag should be comprehensively considered in combination with the transportation capacity of the vertical shaft / inclined shaft and the underground hoisting capacity during the excavation construction of the compressed air energy storage underground chamber. Under the condition that the hoisting capacity is satisfied, the larger the volume of a single rubber bag, the fewer the number of rubber bags required and the better the economy.

[0011] Preferably, the fixing device includes several embedded steel members and several strong magnets. The several embedded steel members are respectively welded to the main bars of the chamber lining, the several embedded steel members are respectively embedded in the concrete lining of the chamber lining, the inner surfaces of the several embedded steel members are flush with the wall surface of the chamber lining, and the several strong magnets are respectively arranged in the series-connected rubber air storage bag, and each strong magnet is magnetically connected to one of the embedded steel members. The fixing device uses a combination of embedded steel members and strong magnets to support and fix the rubber bag, with a simple structure, no need to open holes in the rubber bag, and no damage to the integrity and air tightness of the rubber bag. The quantity, specifications and positions of the embedded steel members and strong magnets can be flexibly adjusted and determined according to the diameter, thickness, weight, etc. of the rubber bag.

[0012] Further, the several embedded steel members are several embedded steel plates, and the several strong magnets are several neodymium iron boron magnets. After the embedded steel plates are welded to the main reinforcement bars of the inner lining of the cavern, when pouring the concrete lining of the inner lining of the cavern, the embedded steel plates can be closely attached to the inner lining formwork. After pouring is completed, the contact boundary between the embedded steel plates and the concrete lining is trimmed to make the embedded steel plates flush with the wall surface of the inner lining of the cavern, ensuring that there will be no protruding surface scratching the subsequently installed rubber bladder.

[0013] Preferably, an installation hole is provided in the middle of the partition wall, the flange is installed in the installation hole, and vent holes communicating with the installation hole are respectively provided in the side walls of two adjacent rubber bladders.

[0014] Further, the flange includes a first flange ring, a second flange ring and a third flange ring. The inner holes of the first flange ring, the second flange ring and the third flange ring are coaxially arranged with the installation hole and the vent holes. The second flange ring is fixed in the middle of the partition wall. The first flange ring and the third flange ring are respectively arranged in two adjacent rubber bladders and press against the outer peripheral edge of the corresponding vent hole. A plurality of bolt holes are respectively axially provided in the first flange ring, the second flange ring and the third flange ring. The first flange ring, the second flange ring and the third flange ring are fixedly connected by a plurality of bolts. The second flange ring serves to fix the flange in the middle of the partition wall, preventing damage to the rubber bladder caused by the movement or rotation of the flange. By using a plurality of bolts to fix the first flange ring, the second flange ring, the third flange ring and the side wall of the rubber bladder together in the middle of the partition wall, the structure is simple, the construction operation is convenient, and it plays a role in clamping and sealing the outer peripheral edge of the vent hole on the side wall of the rubber bladder, ensuring the sealing effect at the interface of the series-connected rubber air storage bladder. The sizes of the inner holes of the first flange ring, the second flange ring and the third flange ring should be designed to allow construction personnel and equipment to pass through.

[0015] Preferably, the surface of the partition wall is arc-transitionally connected to the wall surface of the inner lining of the cavern to prevent stress concentration damage to the rubber bladder.

[0016] Preferably, the drainage system includes a drainage channel and a plurality of catch wells. The drainage channel is arranged longitudinally and continuously along the inner lining of the cavern, the plurality of catch wells are arranged longitudinally at intervals along the bottom of the inner lining of the cavern, one catch well is provided below each rubber bladder, and the plurality of catch wells are respectively communicated with the drainage channel.

[0017] Preferably, each rubber bladder is integrally formed without splicing in the factory. It should undergo airtightness quality inspection when leaving the factory. After passing the quality inspection, it is transported to the construction site of the compressed air energy storage underground cavern for installation. After installation, the quality of each rubber bladder can also be detected one by one, which is convenient for quality inspection and construction quality control.

[0018] Compared with the prior art, the present invention has the following advantages: 1) The compressed air energy storage underground chamber of the present invention with a series-connected rubber airbag adopts a series-connected rubber airbag formed by sequentially connecting multiple rubber bags in series. Each single rubber bag is light in weight and small in volume, facilitating construction operations and having good installation effects. Moreover, the series-connected rubber airbag has fewer interfaces and good airtightness. In addition, the flange is embedded and installed in the isolation wall, and the isolation wall supports the side walls of the flange and the rubber bag, which can ensure uniform stress on the rubber bag, prevent the rubber bag from being torn, and also avoid the adhesion of the side walls of two adjacent rubber bags, preventing uneven expansion of the rubber bag and ensuring the service effect and lifespan of the series-connected rubber airbag; 2) The maintenance and repair costs of the compressed air energy storage underground chamber of the present invention are low. If local air leakage of a rubber bag is found, local repair or overall replacement can be adopted for the leaking rubber bag. The replacement of the rubber bag is convenient, with simple operations and low costs, and there is no need to replace the entire series-connected rubber airbag; 3) During the operation of the compressed air energy storage underground chamber of the present invention, during the cyclic charging and discharging process, the series-connected rubber airbag can be effectively supported, avoiding uneven deformation of the series-connected rubber airbag during cyclic charging and discharging operations, and avoiding the generation of weak points due to local folding of the rubber bag caused by deflation. Moreover, it avoids the contact and adhesion between the side walls of the rubber bag under the deflation condition, ensuring the operation cycle of the compressed air energy storage underground chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a longitudinal sectional view of the compressed air energy storage underground chamber in the embodiment; Figure 2 is a cross-sectional view of the compressed air energy storage underground chamber in the embodiment; Figure 3 is Figure 2 the enlarged view at A in Figure 4 is Figure 2 the enlarged view at B in Figure 5 is a longitudinal sectional view of the first flange ring, the second flange ring, and the third flange ring in the embodiment; Figure 6 is a front view of the first flange ring in the embodiment; Figure 7 is a longitudinal sectional perspective view of the first flange ring in the embodiment; Figure 8 is a longitudinal sectional perspective view of the second flange ring in the embodiment; Figure 9 is a connection diagram of the flange and the rubber bag in the embodiment; The specific reference numerals in the drawings are as follows: 1 - Inner lining of the chamber, 11 - Sealing door of the chamber, 12 - Air inlet and outlet pipe, 2 - Rubber bladder, 21 - Vent hole, 3 - Partition wall, 31 - Installation hole, 4 - Fixing device, 41 - Embedded steel member, 42 - Strong magnet, 5 - Flange, 51 - First flange ring, 52 - Second flange ring, 53 - Third flange ring, 54 - Inner hole, 55 - Bolt hole, 56 - Bolt, 61 - Drainage channel, 62 - Sump well. Detailed implementation mode

[0020] The present invention will be further described in detail below in conjunction with the embodiments in the drawings. Structures or components not defined in the present invention all adopt conventional technical means in the art.

[0021] The compressed air energy storage underground chamber with a series - connected rubber air storage bladder in the embodiment is as Figures 1 to 4 shown, and includes an inner lining 1 of the chamber, a series - connected rubber air storage bladder, a partition wall 3 and a drainage system. The inner lining 1 of the chamber is arranged in the surrounding rock (not shown in the figure). A sealing door 11 of the chamber and an air inlet and outlet pipe 12 are provided on one side of the inner lining 1 of the chamber. The air inlet and outlet pipe 12 communicates with the series - connected rubber air storage bladder. The series - connected rubber air storage bladder is arranged in the inner lining 1 of the chamber. The series - connected rubber air storage bladder is formed by sequentially connecting 4 rubber bladders 2 in series along the longitudinal direction of the inner lining 1 of the chamber. Each rubber bladder 2 is integrally formed. The upper half of each rubber bladder 2 is closely fixed to the wall surface of the inner lining 1 of the chamber through a fixing device 4. The lower half of each rubber bladder 2 hangs naturally. Adjacent rubber bladders 2 are connected through a flange 5. A partition wall 3 is provided between adjacent rubber bladders 2. The partition wall 3 is integrally arranged with the inner lining 1 of the chamber along the transverse direction of the inner lining 1 of the chamber. The surface of the partition wall 3 is arc - transitionally connected with the wall surface of the inner lining 1 of the chamber. The flange 5 is embedded and installed in the partition wall 3. The drainage system is arranged at the bottom of the inner lining 1 of the chamber. The drainage system includes a drainage channel 61 and 4 sump wells 62. The drainage channel 61 is arranged longitudinally and continuously along the inner lining 1 of the chamber. The 4 sump wells 62 are arranged at intervals longitudinally at the bottom of the inner lining 1 of the chamber. One sump well 62 is provided below each rubber bladder 2. The 4 sump wells 62 are respectively communicated with the drainage channel 61.

[0022] In this embodiment, the fixing device 4 includes a number of embedded steel members 41 and a number of strong magnets 42. The number of embedded steel members 41 are respectively welded to the main reinforcement bars (not shown in the figure) of the inner lining 1 of the chamber. The number of embedded steel members 41 are respectively buried in the concrete lining of the inner lining 1 of the chamber. The inner surfaces of the number of embedded steel members 41 are flush with the wall surface of the inner lining 1 of the chamber. The number of strong magnets 42 are respectively arranged in the series - connected rubber air storage bladder. Each strong magnet 42 is magnetically connected to one embedded steel member 41. Specifically, the number of embedded steel members 41 are a number of embedded steel plates, and the number of strong magnets 42 are a number of neodymium iron boron magnets.

[0023] In this embodiment, an installation hole 31 is formed in the middle of the partition wall 3, the flange 5 is installed in the installation hole 31, and air vents 21 communicating with the installation hole 31 are respectively formed in the side walls of two adjacent rubber bags 2. Specifically, as Figures 5 to 9 shown, the flange 5 includes a first flange ring 51, a second flange ring 52 and a third flange ring 53. The inner holes 54 of the first flange ring 51, the second flange ring 52 and the third flange ring 53 are coaxially arranged with the installation hole 31 and the air vents 21. The second flange ring 52 is fixed in the middle of the partition wall 3. The first flange ring 51 and the third flange ring 53 have the same structure. The first flange ring 51 and the third flange ring 53 are respectively arranged in two adjacent rubber bags 2 and press against the outer periphery of the corresponding air vents 21. A plurality of bolt holes 55 are respectively formed axially in the first flange ring 51, the second flange ring 52 and the third flange ring 53. The first flange ring 51, the second flange ring 52 and the third flange ring 53 are fixedly connected by a plurality of bolts 56.

[0024] During the construction process of the above-mentioned compressed air energy storage underground chamber, after the embedded steel plate is welded to the main reinforcement of the inner lining 1 of the chamber, when pouring the concrete lining of the inner lining 1 of the chamber, the embedded steel plate can be closely attached to the inner lining pouring formwork (not shown in the figure). After pouring, the contact boundary between the embedded steel plate and the concrete lining is trimmed to make the embedded steel plate flush with the wall surface of the inner lining 1 of the chamber, ensuring that there is no protruding surface to scratch the subsequent installed rubber bag 2. It should be ensured that the wall surface of the inner lining 1 of the chamber is integrally smooth and flat, without sharp protrusions or edges. When necessary, measures such as applying lubricant or laying geotextile can be taken to reduce the frictional force between the inner lining 1 of the chamber and the series-connected rubber air storage bag.

[0025] The partition wall 3 can be secondarily tied and poured by using the reserved steel bars during the construction of the inner lining 1 of the chamber to reduce the difficulty of laying and pouring the inner lining formwork. The second flange ring 52 and the partition wall 3 can adopt a variety of existing known connection methods. Each rubber bag 2 is integrally formed without splicing in the factory and should undergo airtightness quality inspection before leaving the factory. After passing the quality inspection, it is transported to the construction site of the compressed air energy storage underground chamber and transported to the inner lining 1 of the chamber one by one. A temporary support structure (not shown in the figure) is used to support the rubber bag 2, so that the upper half of the rubber bag 2 is attached to the wall surface of the inner lining 1 of the chamber. Then, a strong magnet 42 is placed inside the rubber bag 2 to magnetically connect each strong magnet 42 with a piece of embedded steel member 41.

[0026] After all the rubber bags 2 in the inner lining 1 of the chamber are installed, the adjacent two rubber bags 2 are connected through the flange 5. Then, the connection quality of each rubber bag 2 and its connection with the flange 5 is inspected one by one. After ensuring that there is no folding, adhesion, local protrusion or damage on the surface of each rubber bag 2, compressed air can be introduced into the series-connected rubber air storage bag through the air inlet and outlet pipe 12, and a high-pressure airtightness test under the actual operating conditions of the compressed air energy storage underground chamber can be carried out.

[0027] Under the air inflation condition, the series-connected rubber airbag closely adheres to the wall surface of the inner lining 1 of the underground chamber, transfers the internal pressure to the surrounding rock through the inner lining 1 of the underground chamber, and the reaction of the surrounding rock makes the internal and external pressures of the series-connected rubber airbag reach equilibrium, thereby sealing the compressed air energy storage underground chamber; under the air deflation condition, the upper half of each rubber bag 2 closely adheres to the wall surface of the inner lining 1 of the underground chamber, and the lower half of each rubber bag 2 is separated from the wall surface of the inner lining 1 of the underground chamber and is in an unconstrained state of natural drooping, ensuring the overall shape of the series-connected rubber airbag and avoiding adhesion, uneven expansion or contraction of the series-connected rubber airbag caused by repeated inflation and deflation. Under the air inflation and deflation conditions, the condensed water in the compressed air energy storage underground chamber and the groundwater infiltrating into the compressed air energy storage underground chamber can freely drain out of the chamber through the drainage system, and the overall shape of the series-connected rubber airbag remains basically unchanged.

[0028] When the inside of the compressed air energy storage underground chamber is in a standard atmospheric pressure state for a long time, the rubber between the fixing devices 4 may produce a certain amount of bending deformation under the action of gravity, creating a gap with the wall surface of the inner lining 1 of the underground chamber. To avoid this phenomenon, under normal operating conditions, the air pressure inside the chamber should be kept higher than the air pressure outside the chamber as much as possible, or the low air pressure state inside the chamber should be shortened, and the amount of use of the fixing devices 4 should be increased during the construction of the compressed air energy storage underground chamber to minimize the distance between the fixing devices 4.

Claims

1. A compressed air energy storage underground cavern with a series of rubber air storage bags, characterized in that: It includes a cavern lining, a series of rubber air storage bags, an isolation wall and a drainage system. The cavern lining is arranged in the surrounding rock. One side of the cavern lining is provided with a cavern sealing door and an air inlet and outlet pipe. The air inlet and outlet pipe are communicated with the series of rubber air storage bags. The series of rubber air storage bags are arranged in the cavern lining. The series of rubber air storage bags are formed by a plurality of rubber bags connected in series in the longitudinal direction of the cavern lining. Each of the rubber bags is integrally formed. The upper half of each of the rubber bags is tightly fixed to the wall surface of the cavern lining by a fixing device. The lower half of each of the rubber bags droops naturally. Two adjacent rubber bags are connected by a flange. An isolation wall is provided between two adjacent rubber bags. The isolation wall is integrally arranged with the cavern lining along the transverse direction of the cavern lining. The flange is embedded in the isolation wall. The drainage system is arranged at the bottom of the cavern lining.

2. The compressed air energy storage underground cavern with a series-connected rubber air storage bag according to claim 1 is characterized in that: The fixing device includes a plurality of embedded steel components and a plurality of strong magnets. The plurality of embedded steel components are respectively welded to the main reinforcement of the cavern lining, the plurality of embedded steel components are respectively buried in the concrete lining of the cavern lining, the inner surfaces of the plurality of embedded steel components are respectively flush with the wall surface of the cavern lining, the plurality of strong magnets are respectively arranged in the series-connected rubber air storage bags, and each of the strong magnets is magnetically connected to one of the embedded steel components.

3. The compressed air energy storage underground cavern with a series-connected rubber air storage bag according to claim 2 is characterized in that: The plurality of embedded steel components are a plurality of embedded steel plates, and the plurality of strong magnets are a plurality of neodymium iron boron magnets.

4. The compressed air energy storage underground cavern with a series-connected rubber air storage bag according to claim 1 is characterized in that: A mounting hole is provided in the middle of the isolation wall, the flange is installed in the mounting hole, and two adjacent side walls of the rubber bags are respectively provided with ventilation holes communicating with the mounting hole.

5. The compressed air energy storage underground cavern with a series-connected rubber air storage bag according to claim 4 is characterized in that: The flange includes a first flange ring, a second flange ring and a third flange ring. The inner holes of the first flange ring, the second flange ring and the third flange ring are coaxially arranged with the mounting hole and the vent hole. The second flange ring is fixed to the middle of the isolation wall. The first flange ring and the third flange ring are respectively arranged in two adjacent rubber bags and press the outer periphery of the corresponding vent hole. The first flange ring, the second flange ring and the third flange ring are respectively provided with a plurality of bolt holes in the axial direction. The first flange ring, the second flange ring and the third flange ring are fixedly connected by a plurality of bolts.

6. The compressed air energy storage underground cavern with serially connected rubber air storage bags according to claim 1, characterized in that: The surface of the isolation wall is transitionally connected to the curved surface of the wall of the cavern lining.

7. The compressed air energy storage underground cavern with serially connected rubber air storage bags according to claim 1, characterized in that: The drainage system includes a drainage channel and a plurality of water collection wells. The drainage channel is arranged along the longitudinal length of the cavern lining. The plurality of water collection wells are arranged at intervals along the longitudinal direction of the bottom of the cavern lining. A water collection well is provided under each of the rubber bags. The plurality of water collection wells are respectively connected to the drainage channel.

8. The compressed air energy storage underground cavern with serially connected rubber air storage bags according to claim 1, characterized in that: Each of the rubber bladders is integrally formed without splicing at the factory.

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