A protective gravity compressed air energy storage system that reduces the impact force of gravity pressing blocks

Abstract

The present application proposes a protective gravity compressed air energy storage system for reducing the impact force of gravity pressure blocks, comprising a vertical shaft and an annular locking platform, wherein a gravity component is movably inserted in the vertical shaft, and the gravity component and the vertical shaft are sealed by a sealing membrane so that the gravity component, the sealing membrane and the area below the sealing membrane form an air storage chamber, and the annular locking platform is arranged on the vertical shaft, and the annular locking platform is sleeved on the outside of the gravity component, and a plurality of dampers are arranged on the annular locking platform, and the plurality of dampers form an annular structure so that when the gravity component moves downward to the damper, it is supported by the plurality of dampers. By arranging a plurality of dampers, the impact force generated by the gravity component under an accident condition is weakened through buffering, thereby reducing the downward impact force of the gravity component under the accident condition, weakening the secondary damage after the accident, and ensuring the overall safety of the vertical shaft structure.

Description

Technical Field

[0001] The present application relates to the field of electric energy storage technology, and in particular to a protective gravity compressed air energy storage system that reduces the impact force of gravity pressing blocks. Background Art

[0002] The compressed air energy storage system stores excess electrical energy by compressing air, and the gravity briquette is characterized by its large size and weight. When storing energy, the compressed air energy storage system consumes electrical energy to compress the air and store it in the air storage chamber. The top plate of the air storage chamber rises, lifting the gravity briquette. When releasing energy, high-pressure air is released from the air storage chamber, and the gravity briquette descends along with the top plate of the air storage chamber. Under normal working conditions, the gravity briquette can rise and fall smoothly. However, in accident conditions, such as when the raised gravity briquette is lifted to the highest point, the gravity briquette suddenly falls due to a sudden drop in air pressure in the slot or air storage chamber. The huge impact force causes serious damage to the energy storage shaft. Summary of the Invention

[0003] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the purpose of this application is to propose a protective gravity compressed air energy storage system that reduces the impact force of gravity pressure blocks. By setting up multiple dampers, the impact force generated by the gravity component under accident conditions is weakened through buffering, thereby reducing the downward impact force of the gravity component under accident conditions, weakening the secondary damage after the accident, and ensuring the overall safety of the shaft structure.

[0005] To achieve the above objectives, the present application proposes a protective gravity compressed air energy storage system that reduces the impact force of gravity pressing blocks, comprising:

[0006] A vertical shaft, wherein a gravity assembly is movably inserted into the vertical shaft, and the gravity assembly and the vertical shaft are sealed by a sealing membrane, so that an air storage chamber is enclosed by the gravity assembly, the sealing membrane, and the area of the vertical shaft below the sealing membrane;

[0007] An annular locking platform is arranged on the vertical shaft, and the annular locking platform is sleeved on the outside of the gravity component. A plurality of dampers are provided on the annular locking platform, and the plurality of dampers form an annular structure so that the gravity component is supported by the plurality of dampers when it moves downward to the dampers.

[0008] Furthermore, a plurality of angle steels are fixed on the circumferential side of the inner wall of the annular locking platform, one side of the angle steel is fixed on the inner wall of the annular locking platform, the damper is arranged on the other side surface of the angle steel, and an elastic pad is provided on the surface of the annular locking platform so that the gravity assembly moves downward to connect with the plurality of the dampers and then compresses the damper until the gravity assembly is supported on the elastic pad.

[0009] Furthermore, the gravity assembly includes an above-ground gravity block group and a pressure-bearing cylinder, the above-ground gravity block group is arranged at the top of the pressure-bearing cylinder, the sealing membrane is connected to the outer wall of the pressure-bearing cylinder, and a limiting ring is provided on the top outer wall of the pressure-bearing cylinder, so that the limiting ring of the pressure-bearing cylinder is connected to the multiple dampers and compresses the dampers until the gravity assembly is supported on the elastic pad.

[0010] Furthermore, the annular locking platform is arranged on the ground at the top of the shaft.

[0011] Furthermore, it also includes:

[0012] A guide groove, wherein a plurality of guide grooves are provided, a plurality of tower structures are provided on the ground outside the top of the shaft, the plurality of tower structures are distributed around the shaft, and the plurality of guide grooves are respectively installed on the plurality of tower structures;

[0013] There are multiple rollers, and the multiple rollers are respectively arranged on the peripheral sides of the ground gravity block group through rotating shafts. The rollers are connected to the bottom of the guide groove so that when the gravity assembly moves up and down, the rollers move up and down along the bottom of the guide groove.

[0014] Furthermore, the above-ground gravity block group includes a plurality of above-ground gravity pressing blocks stacked in layers in the vertical direction, and a plurality of rollers are provided on the circumference of each above-ground gravity pressing block.

[0015] Furthermore, a mounting groove is opened on the peripheral side of the gravity pressure block, a steel plate groove is installed in the mounting groove, the roller is located in the steel plate groove, and the rotating shaft connected to the roller is installed between the side walls on opposite sides of the steel plate groove.

[0016] Furthermore, the damper includes a top support and a bottom support arranged opposite to each other and a spring connected between the top support and the bottom support, the top end and the bottom end of the spring are respectively connected to the top support and the bottom support, and the bottom support is arranged on the other side surface of the angle steel;

[0017] An upper center connecting rod is provided in the middle of the bottom surface of the top support, and a lower center connecting rod is provided in the middle of the surface of the bottom support. The upper center connecting rod and the lower center connecting rod are both located in the middle of the spring. A sliding hole arranged in the vertical direction is opened in the middle of the top end surface of the lower center connecting rod. The bottom end of the upper center connecting rod is located in the sliding hole and can move up and down along the sliding hole.

[0018] Furthermore, an upper annular protective ring is provided on the bottom surface of the top support, and a lower annular protective ring is provided on the surface of the bottom support. The upper annular protective ring and the lower annular protective ring are located in the upper annular protective ring, and the spring is located in the lower annular protective ring.

[0019] Furthermore, the outer diameter of the lower annular protection ring is equal to the inner diameter of the upper annular protection ring.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0022] Figure 1 This is a structural diagram of a protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks proposed in one embodiment of the present application;

[0023] Figure 2 Another embodiment of this application proposes Figure 1 Schematic diagram of the local structure;

[0024] Figure 3 Another embodiment of this application proposes Figure 2 Schematic diagram of the local structure;

[0025] Figure 4 Another embodiment of this application proposes Figure 1 Schematic diagram of the local structure;

[0026] In the figure, 1. vertical shaft; 2. angle steel; 3. sealing membrane; 4. air storage chamber; 5. annular locking platform; 51. elastic pad; 6. damper; 61. top support; 62. bottom support; 63. spring; 65. upper center connecting rod; 66. lower center connecting rod; 67. upper annular protection ring; 68. lower annular protection ring; 7. ground gravity block group; 71. ground gravity pressure block; 72. steel plate groove; 8. pressure cylinder; 81. limiting ring; 9. baffle; 11. guide groove; 12. tower structure; 13. roller; 14. steel lining. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present application and are not to be construed as limiting the present application. On the contrary, the embodiments of the present application include all variations, modifications, and equivalents that fall within the spirit and scope of the appended claims.

[0028] Figure 1 This is a structural schematic diagram of a protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks proposed in one embodiment of the present application.

[0029] See also Figure 1-3 A protective gravity compressed air energy storage system for reducing the impact force of a gravity pressure block includes a vertical shaft 1, in which a gravity component is movably inserted. The gravity component and the vertical shaft 1 are sealed by a sealing membrane 3, so that the gravity component, the sealing membrane 3 and the area of the vertical shaft 1 below the sealing membrane 3 form an air storage chamber 4. An annular locking platform 5 is provided on the vertical shaft 1, and the annular locking platform 5 is sleeved on the outside of the gravity component. A plurality of dampers 6 are provided on the annular locking platform 5, and the plurality of dampers 6 form an annular structure so that the gravity component is supported by the plurality of dampers 6 when it moves downward to the damper 6.

[0030] It can be understood that the air storage chamber 4 is connected to the air compressor unit and the air expansion unit. During the energy storage process, the electric energy drives the air compressor unit to work, and the air compressor unit introduces compressed air into the air storage chamber 4. The pressure of the compressed air pushes the gravity assembly to move upward until the gravity assembly moves upward to the upper limit and stops. At this time, compressed air is stored in the air storage chamber 4. When releasing energy, the compressed air in the air storage chamber 4 is introduced into the air expansion unit, driving the air expansion unit to work and realize power generation. When the compressed air in the air storage chamber 4 is introduced into the air expansion unit, the gravity assembly moves downward until the gravity assembly is connected to the damper 6. The damper 6 has a certain buffering effect on the gravity assembly, thereby realizing protection of the gravity assembly. Under accident conditions, when the gravity assembly freely falls and contacts the annular steel plate at the top of the damper 6, the impact load generated by the gravity assembly is evenly distributed and transmitted to the multiple dampers 6 on the surrounding side, thereby maximizing the buffering effect of the damper 6.

[0031] In addition, it should be noted that the sealing membrane 3 is an existing structure, and the sealing connection between the sealing membrane 3 and the inner wall of the shaft 1 and the outer wall of the gravity assembly is also an existing technology, which will not be described in detail here, and multiple dampers 6 are arranged at equal angles on the side of the annular locking platform 5.

[0032] In some embodiments, multiple angle steels 2 are fixed on the inner wall of the annular locking platform 5, one side of the angle steel 2 is fixed on the inner wall of the annular locking platform 5, and the damper 6 is arranged on the other side surface of the angle steel 2. The surface of the annular locking platform 5 is provided with an elastic pad 51, so that the gravity component moves downward to connect with the multiple dampers 6 and then compresses the damper 6 until the gravity component is supported on the elastic pad 51.

[0033] It can be understood that under accident conditions, the impact load generated by the free fall of the gravity component is evenly distributed and transmitted to each damper 6, maximizing the buffering effect of the damper 6. After the damper 6 reaches its limit state, the gravity component is connected to the elastic pad 51, and the elastic pad 51 can again play a certain buffering and vibration reduction role.

[0034] It should be noted that the elastic pad 51 may be a rubber pad, which has a certain elasticity and can achieve a buffering and shock-absorbing effect.

[0035] In some embodiments, the gravity assembly includes a ground gravity block group 7 and a pressure cylinder 8. The ground gravity block group 7 is arranged on the top of the pressure cylinder 8. The sealing membrane 3 is connected to the outer wall of the pressure cylinder 8. A limiting ring 81 is provided on the top outer wall of the pressure cylinder 8, so that the limiting ring 81 of the pressure cylinder 8 is connected to multiple dampers 6 and compresses the dampers 6 until the gravity assembly is supported on the elastic pad 51.

[0036] It is understandable that the pressure-bearing cylinder 8 can be set as a cylindrical structure surrounded by steel plates, and then sand can be filled inside the cylindrical structure. During installation, since the interior of the pressure-bearing cylinder 8 is a hollow structure, the weight is reduced, which makes it easier to lift. After being lifted into the vertical shaft 1 and blocked by the limiting ring 81, sand is then filled into the pressure-bearing cylinder 8 to reduce the difficulty of lifting. In addition, since the energy storage pressure in the air storage chamber 4 is relatively high, about 10Mpa, and the gravity components are generally made of concrete, air leakage will occur under the action of high-pressure air. By setting up a pressure-bearing cylinder 8 surrounded by a steel plate structure, the air tightness can be improved to prevent air leakage, thereby ensuring the sealing characteristics of the air storage chamber 4, and being able to withstand higher pressures, thereby improving the energy density of the system's energy storage.

[0037] In addition, a steel lining 14 is fixed to the inner wall of the shaft 1, and the pressure cylinder 8 is a cylindrical structure surrounded by steel plates. The sealing membrane 3 is connected to the inner wall of the steel lining 14 and the outer wall of the pressure cylinder 8. By setting the steel lining 14, it can be ensured that the inner wall of the shaft 1 is a smooth wall surface, and since the pressure cylinder 8 is also a cylindrical structure surrounded by steel plates, it is also a smooth outer wall surface structure. Therefore, when the sealing membrane 3 is fixed on the steel lining 14 and the pressure cylinder 8, the sealing performance can be improved and the installation of the sealing membrane 3 is facilitated.

[0038] In some embodiments, the annular locking platform 5 is set on the ground at the top of the shaft 1, so that the annular locking platform 5 and the damper 6 are both located on the ground, which is convenient for installation. In addition, the ground gravity block group 7 is located on the ground. When realizing large energy storage, there is no need to concentrate all gravity components in the shaft 1, which can reduce the height of the shaft 1 and greatly reduce the excavation volume and engineering difficulty of the shaft 1.

[0039] In some embodiments, it also includes a guide groove 11 and a roller 13. There are multiple guide grooves 11. A plurality of tower structures 12 are set on the ground outside the top of the shaft 1. The plurality of tower structures 12 are distributed around the shaft 1. The plurality of guide grooves 11 are respectively installed on the plurality of tower structures 12. There are multiple rollers 13. The plurality of rollers 13 are respectively set on the periphery of the gravity block group 7 on the ground through a rotating shaft. The rollers 13 are connected to the bottom of the guide groove 11, so that the rollers 13 move up and down along the bottom of the guide groove 11 when the gravity assembly moves up and down.

[0040] It can be understood that a plurality of tower structures 12 are provided on the ground outside the top of the shaft 1, and the plurality of tower structures 12 are distributed around the shaft 1, and the plurality of guide grooves 11 are respectively installed on the plurality of tower structures 12, that is, four tower structures 12 can be provided, and then four guide grooves 11 are provided on the four tower structures 12 outside the shaft 1, and each tower structure 12 is provided with a guide groove 11. Since the roller 13 on the ground gravity block group 7 is installed around the ground gravity block group 7 through a rotating shaft, the roller 13 can rotate on the ground gravity block group 7. When the roller 13 is connected to the bottom of the guide groove 11, it can not only be limited by the guide groove 11, but the guide groove 11 cooperates with the roller 13 to constrain the movement direction of the ground gravity block group 7. At the same time, the ground gravity block group 7 moves vertically upward or downward along the guide groove 11 at a certain rate. Lubricant, such as butter or graphite, is regularly added to the contact position between the guide groove 11 and the roller 13 to reduce friction and improve the conversion rate of gravitational potential energy.

[0041] In some embodiments, the ground gravity block group 7 includes a plurality of ground gravity pressure blocks 71 stacked in layers in the vertical direction, and a plurality of rollers 13 are provided on the circumference of each ground gravity pressure block 71 .

[0042] It can be understood that by arranging the ground gravity block group 7 into multiple superimposed ground gravity pressure blocks 71, the weight of each ground gravity pressure block 71 is reduced, and the difficulty of lifting is reduced while meeting the large energy storage requirement. During the lifting construction process, the pressure cylinder 8 is first lifted into the vertical shaft 1, and the pressure cylinder 8 is supported on the ground by the limit ring 81. Then, the ground gravity pressure blocks 71 are lifted layer by layer on the top of the pressure cylinder 8. In addition, through the setting of multiple dampers 6, the impact force between the ground gravity block groups 7 and between the pressure cylinder 8 and the top ground of the vertical shaft 1 can be reduced under accident conditions, thereby weakening the secondary damage after the accident and ensuring the overall safety of the vertical shaft 1 structure.

[0043] In some embodiments, each ground gravity pressure block 71 has an installation groove on its circumferential side, a steel plate groove 72 is installed in the installation groove, the roller 13 is located in the steel plate groove 72, and the rotating shaft connected to the roller 13 is installed between the side walls on opposite sides of the steel plate groove 72.

[0044] It is understood that the steel plate trough 72 includes two opposing side walls, with a bottom plate connected between the two opposing side walls. The bottom plate is fixed to the bottom of the mounting trough, and the two side walls are fixed to the two opposing side walls of the mounting trough. The rotating shaft is then installed between the two side walls, and there is a gap between the roller 13 and the bottom of the steel plate trough 72, i.e., the bottom plate, so that the roller 13 does not hit the bottom of the steel plate trough 72 during rotation. Mounting holes are opened on the opposing side walls of the steel plate trough 72, and bearings are installed in the mounting holes. The two ends of the rotating shaft are respectively mounted on the bearings on the opposing side walls of the steel plate trough 72.

[0045] In addition, it also includes a baffle 9, and multiple baffles 9 are provided. The multiple baffles 9 are respectively arranged on the top of multiple tower structures 12. The multiple baffles 9 are at the same distance from the ground at the top of the shaft 1. When the ground gravity pressure block 71 rises to the limit elevation, it still has a certain inertia. The baffle 9 can prevent the ground gravity pressure block 71 from continuing to move upward after rising to the limit elevation. The baffle 9 is a concrete baffle, and the concrete baffle and the tower structure 12 are cast as a whole.

[0046] See also Figure 4 In some embodiments, the damper 6 includes a top support 61 and a bottom support 62 arranged opposite to each other and a spring 63 connected between the top support 61 and the bottom support 62. The top and bottom ends of the spring 63 are respectively connected to the top support 61 and the bottom support 62. The bottom support 62 is arranged on the other side surface of the angle steel 2. An upper center link 65 is arranged in the middle of the bottom surface of the top support 61, and a lower center link 66 is arranged in the middle of the surface of the bottom support 62. The upper center link 65 and the lower center link 66 are both located in the middle of the spring 63. A sliding hole arranged in the vertical direction is opened in the middle of the top surface of the lower center link 66. The bottom end of the upper center link 65 is located in the sliding hole and can move up and down along the sliding hole.

[0047] It can be understood that the upper center link 65 is limited by the lower center link 66 by the upper center link 65 moving up and down in the sliding hole in the lower center link 66. Since the top and bottom ends of the spring 63 are respectively connected to the top support 61 and the bottom support 62, the spring 63 can push the top support 61 upward under the action of the elastic force. Under the downward action of the gravity component, a certain force is applied to the top support 61, and the spring 63 is compressed for buffering. The upper center link 65 slides downward in the sliding hole in the lower center link 66 until the gravity component is connected to the elastic pad 51 for one step of buffering, and the buffering effect of the gravity component is achieved through multiple dampers 6.

[0048] In some embodiments, an upper annular protective ring 67 is provided on the bottom surface of the top support 61, and a lower annular protective ring 68 is provided on the surface of the bottom support 62. The lower annular protective ring 68 is located in the upper annular protective ring 67, and the spring 63 is located in the lower annular protective ring 68. The outer diameter of the lower annular protective ring 68 is equal to the inner diameter of the upper annular protective ring 67.

[0049] The cam 67 is held in place by the spring 63 to prevent the spring 63 from sliding downwards and causing the spring 63 to slide downwards, thereby preventing the spring 63 from sliding downwards and causing the spring 63 to slide downwards.

[0050] It should be noted that, in the description of this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0051] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0052] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0053] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks, characterized in that: include: A vertical shaft, wherein a gravity assembly is movably inserted into the vertical shaft, and the gravity assembly and the vertical shaft are sealed by a sealing membrane, so that an air storage chamber is enclosed by the gravity assembly, the sealing membrane, and the area of the vertical shaft below the sealing membrane; an annular locking platform, the annular locking platform being arranged on the shaft and sleeved on the outside of the gravity assembly, the annular locking platform being provided with a plurality of dampers, the plurality of dampers forming an annular structure so that the gravity assembly is supported by the plurality of dampers when it moves downward to the dampers; A plurality of angle steels are fixed to the inner wall of the annular locking platform, one side of the angle steels being fixed to the inner wall of the annular locking platform, the damper being arranged on the other side of the angle steel, and an elastic pad being arranged on the surface of the annular locking platform so that the gravity assembly moves downward to contact the plurality of dampers and then compresses the damper until the gravity assembly is supported on the elastic pad; The gravity assembly includes an above-ground gravity block group and a pressure-bearing cylinder. The above-ground gravity block group is arranged on the top of the pressure-bearing cylinder. The sealing membrane is connected to the outer wall of the pressure-bearing cylinder. A limiting ring is provided on the top outer wall of the pressure-bearing cylinder so that the limiting ring of the pressure-bearing cylinder is connected to the multiple dampers and then compresses the dampers until the gravity assembly is supported on the elastic pad.

2. A protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks according to claim 1, characterized in that: The annular locking platform is arranged on the ground at the top of the shaft.

3. A protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks according to claim 2, characterized in that: Also includes: A guide groove, wherein a plurality of guide grooves are provided, a plurality of tower structures are provided on the ground outside the top of the shaft, the plurality of tower structures are distributed around the shaft, and the plurality of guide grooves are respectively installed on the plurality of tower structures; and There are multiple rollers, and the multiple rollers are respectively arranged on the peripheral sides of the ground gravity block group through rotating shafts. The rollers are connected to the bottom of the guide groove so that when the gravity assembly moves up and down, the rollers move up and down along the bottom of the guide groove.

4. A protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks according to claim 3, characterized in that: The above-ground gravity block group includes a plurality of above-ground gravity pressing blocks stacked in layers in a vertical direction, and a plurality of rollers are provided on the circumference of each above-ground gravity pressing block.

5. A protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks according to claim 4, characterized in that: An installation groove is opened on the peripheral side of the gravity pressure block, a steel plate groove is installed in the installation groove, the roller is located in the steel plate groove, and the rotating shaft connected to the roller is installed between the side walls on opposite sides of the steel plate groove.

6. The protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks according to claim 1, characterized in that: The damper includes a top support and a bottom support arranged opposite to each other, and a spring connected between the top support and the bottom support, wherein the top and bottom ends of the spring are respectively connected to the top support and the bottom support, and the bottom support is arranged on the other side surface of the angle steel; An upper center connecting rod is provided in the middle of the bottom surface of the top support, and a lower center connecting rod is provided in the middle of the surface of the bottom support. The upper center connecting rod and the lower center connecting rod are both located in the middle of the spring. A sliding hole arranged in the vertical direction is opened in the middle of the top end surface of the lower center connecting rod. The bottom end of the upper center connecting rod is located in the sliding hole and can move up and down along the sliding hole.

7. A protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks according to claim 6, characterized in that: An upper annular protection ring is provided on the bottom surface of the top support, a lower annular protection ring is provided on the surface of the bottom support, the lower annular protection ring is located in the upper annular protection ring, and the spring is located in the lower annular protection ring.

8. A protective gravity compressed air energy storage system for reducing the impact force of gravity pressing blocks according to claim 7, characterized in that: The outer diameter of the lower annular protective ring is equal to the inner diameter of the upper annular protective ring.

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