Liquid hydrogen delivery device and method

Abstract

The present invention discloses a liquid hydrogen delivery device, including a delivery pipe, a pressurizing part, a refrigeration part, a power part and a transmission part. The delivery pipe is composed of a transmission inner pipe and an insulation outer pipe, and a vacuum insulation cavity is provided between the inner and outer pipes. The refrigeration part includes a liquid hydrogen equal distribution component, an inner and outer connecting sleeve, a cold source sleeve, a heat source sleeve and a piston assembly, which are arranged concentrically, and the pressurization and refrigeration of liquid hydrogen are realized through inner and outer annular pistons, a connecting pipe, a crankshaft and a connecting rod mechanism. The power part drives the pressurizing part and the refrigeration part through the transmission part to ensure the stable delivery of liquid hydrogen. The liquid hydrogen delivery method comprises the following steps: using the delivery pipe and the vacuum insulation cavity to maintain the low temperature transmission of liquid hydrogen; pressurizing and cooling the liquid hydrogen through the pressurizing part and the refrigeration part; the power part drives the pressurizing part and the refrigeration part to operate through the transmission part. The present invention significantly improves the efficiency and stability of liquid hydrogen delivery, ensures that liquid hydrogen is efficiently pressurized, cooled and stably delivered in the liquid phase, and has good technical advantages and application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid hydrogen transportation, and in particular to a liquid hydrogen transportation device and method. Background Art

[0002] With the continuous expansion of the application field of liquid hydrogen, liquid hydrogen, as an important carrier of clean energy, is increasingly used in aerospace, industry, energy storage and other fields. As a key equipment in the use of liquid hydrogen, the performance and stability of liquid hydrogen transportation devices directly affect the transportation efficiency and safety of liquid hydrogen. Although the existing liquid hydrogen transportation devices have realized the storage and transportation of liquid hydrogen to a certain extent, there are still some technical difficulties in the pressurization, refrigeration and power transmission of liquid hydrogen, which urgently need further optimization.

[0003] First, liquid hydrogen needs to be kept at an extremely low temperature (about -253°C) during transportation to prevent it from vaporizing or leaking. However, in actual use, existing liquid hydrogen transportation devices often find it difficult to ensure uniform temperature distribution within the transportation pipeline and the device, which may cause temperature fluctuations in the liquid hydrogen during transportation, thereby affecting the stability and transmission efficiency of the liquid hydrogen. Especially in the pressurization and refrigeration stages, how to effectively allocate the liquid hydrogen flow area through reasonable structural design and maintain the liquid hydrogen at a low temperature through the refrigeration system has become a major challenge.

[0004] Secondly, the effective pressurization and refrigeration of liquid hydrogen are the core issues in liquid hydrogen transportation devices. Existing devices often rely on traditional pressurization and refrigeration methods, but due to the unreasonable structural design of the refrigeration and pressurization components, liquid hydrogen cannot be quickly and effectively cooled and pressurized in a short time during transportation, which in turn affects the overall working efficiency of the device. In addition, the heat exchange efficiency between the cold source and the heat source used for liquid hydrogen refrigeration in the existing technology is low, making it difficult to achieve efficient heat management, resulting in high system energy consumption and unstable refrigeration effect.

[0005] Finally, the power system of the liquid hydrogen transport device needs to have a high degree of reliability and redundancy. In traditional designs, the power system often relies on only a single motor or drive source, which can easily lead to the system being unable to provide sufficient redundant power support when the motor fails or the drive fails. Therefore, how to ensure that the device can still operate stably in the event of a failure through reasonable power redundancy design is a technical problem that needs to be solved in the liquid hydrogen transport device. The power transmission system in existing devices often has problems such as unstable motion, which further affects the reliability and safety of the system.

[0006] Therefore, how to improve the stability and reliability of liquid hydrogen transportation equipment, ensure the low temperature environment, pressurization and refrigeration effects of liquid hydrogen, and ensure that the redundant power system can intervene smoothly is an important research direction in the current technical field. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a liquid hydrogen transportation device and method, which significantly improves the performance of the liquid hydrogen transportation device, can not only more effectively maintain the low-temperature environment of liquid hydrogen, but also ensure that the liquid hydrogen is fully pressurized and cooled during the transportation process, while ensuring redundant power intervention of the device in the event of a failure, and has obvious technical advantages and application prospects.

[0008] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a liquid hydrogen transportation device, including a transportation pipe connecting the starting point and the end point of liquid hydrogen transportation, and a pressurizing part and a refrigeration part assembled on the transportation pipe, and also including a power part and a transmission part, and the power part is connected to the pressurizing part and the refrigeration part through the transmission part.

[0009] The conveying pipe comprises a transmission inner pipe and a thermal insulation outer pipe sleeved on the outer side of the transmission inner pipe, and a vacuum thermal insulation cavity is arranged between the thermal insulation outer pipe and the transmission inner pipe.

[0010] The refrigeration part includes a liquid hydrogen equal distribution component, an inner connecting sleeve, a cold source sleeve, an outer connecting sleeve, and a heat source sleeve which are arranged concentrically from the inside to the outside. The inner connecting sleeve is sealedly connected to the transmission inner tube, the outer connecting sleeve is sealedly connected to the insulation outer tube, the inner connecting sleeve is fixedly connected to the cold source sleeve and encloses an inner compression chamber, and the outer connecting sleeve is fixedly connected to the heat source sleeve and encloses an outer compression chamber.

[0011] The refrigeration unit also includes an inner annular piston, an outer annular piston, a connecting pipe, a crankshaft, and a connecting rod mechanism. The inner annular piston and the outer annular piston are respectively assembled in the inner compression chamber and the outer compression chamber. The connecting pipe is connected with the inner compression chamber and the outer compression chamber. The crankshaft is dynamically connected with the transmission unit and the connecting rod mechanism. The connecting rod mechanism is linked with the inner annular piston and the outer annular piston.

[0012] On the basis of the above technical solutions, in order to ensure that the pressurizing unit, the refrigeration unit, the power unit, and the transmission unit can be stably installed and matched, and to ensure that the pressurizing unit can continuously pressurize the transmitted liquid hydrogen and avoid external heat from exchanging heat with the transmitted liquid hydrogen through the pressurizing unit, resulting in the temperature of the liquid hydrogen rising, the following technical solutions are provided:

[0013] It also includes a mounting seat, and the pressurizing part, the refrigeration part, the power part, and the transmission part are all assembled on the mounting seat.

[0014] The pressurizing part includes a thermal insulation cover and a multi-stage centrifugal pump arranged on the inner side of the thermal insulation cover. The thermal insulation cover and the multi-stage centrifugal pump are fixedly mounted on the mounting pad. The inlet and outlet ends of the multi-stage centrifugal pump are sealedly connected to the transmission inner tube. The thermal insulation cover is connected to a connecting pipe arranged on the periphery of the inlet and outlet ends, and the connecting pipe is sealedly connected to the thermal insulation outer tube.

[0015] On the basis of the above technical solutions, in order to ensure that each section of the delivery pipe can be stably connected, to ensure that the delivery pipe can be stably connected to the pressurizing part, and to ensure the heat insulation effect during the liquid hydrogen transmission process, the following technical solutions are provided:

[0016] The end, inlet and outlet of the transmission inner pipe are fixedly connected with flange A, the ends of the insulation outer pipe and the connecting pipe are fixedly connected with flange B, an insulation ring seat is nested between the flange A and flange B, the outer edge of the flange A is nested into the inner edge of the insulation ring seat and fixedly combined by a bolt assembly, the outer edge of the insulation ring seat is nested between two groups of flanges B and fixedly combined by a bolt assembly, and the insulation ring seat and flange A are respectively provided with an external connecting port and an internal connecting port.

[0017] On the basis of the above technical solutions, in order to ensure that the components in the refrigeration unit can be matched and combined, and to achieve effective refrigeration of liquid hydrogen, the following technical solutions are provided:

[0018] The liquid hydrogen equal distribution component includes a guide column and a spiral isolation plate fixed to the periphery of the guide column and maintained evenly distributed, the spiral isolation plate is fixedly connected to the inner connecting sleeve, the inner connecting sleeve is fixedly connected to the cold source sleeve via a connecting ring seat A, the outer connecting sleeve is fixedly connected to the heat source sleeve via a connecting ring seat B, and heat sinks are evenly fixed on the outer wall of the heat source sleeve.

[0019] The two ends of the outer compression chamber are respectively fixed with a connecting cover A and a connecting cover B, and the connecting cover A and the connecting cover B are both fixedly connected to the end of the thermal insulation outer tube. The connecting cover A is fixedly connected to the end of the outer connecting sleeve and the heat source sleeve, and the connecting cover B is fixedly connected to the connecting ring seat B; the connecting pipe and the connecting cover B are sealed and plugged in, and the two ends of the connecting pipe are respectively connected to the connecting ring seat A and the heat source sleeve.

[0020] On the basis of the above technical solution, in order to ensure that the crankshaft can drive the inner annular piston and the outer annular piston to operate stably through the connecting rod mechanism, the following technical solution is provided:

[0021] The inner annular piston and the outer annular piston are respectively fixed with an inner connecting bracket and an outer connecting bracket, and the inner connecting bracket and the outer connecting bracket are both sealed and plugged with the connecting cover A. The inner connecting bracket and the outer connecting bracket are respectively fixed to a guide shaft and a guide sleeve, and the guide shaft and the guide sleeve are slidably plugged.

[0022] The connecting rod mechanism includes a connecting rod A and a connecting rod B. Both the connecting rod A and the connecting rod B are hinged to the crankshaft. The guide shaft is hinged to the connecting rod A. The guide sleeve is hinged to the connecting rod B.

[0023] On the basis of the above technical solution, in order to ensure that the transmission part can be stably installed on the mounting pad and that the transmission part can drive the multi-stage centrifugal pump and the crankshaft to operate stably, the following technical solution is provided:

[0024] The transmission part includes a transmission shaft to drive a driving bevel gear A on the transmission shaft, and an input end of a magnetic coupler. The transmission shaft is rotatably mounted on the mounting pad and is coaxially arranged with the main shaft of the multistage centrifugal pump. The main shaft of the multistage centrifugal pump is fixedly connected with an output end of a magnetic coupler arranged on the inner side of the thermal insulation cover. The input end of the magnetic coupler is relatively arranged with the output end of the magnetic coupler. The crankshaft is rotatably mounted on the mounting pad, and the end of the crankshaft is fixedly connected with a transmission bevel gear A that is meshed with the driving bevel gear A.

[0025] On the basis of the above technical solution, in order to ensure that the power of the driving unit can be stably transmitted to the transmission shaft and provide power redundancy when the device fails, the following technical solution is provided:

[0026] The power unit includes a main motor, an auxiliary motor and a drive shaft. The main motor and the auxiliary motor are fixedly mounted on the mounting pad. The drive shaft is rotatably mounted on the mounting pad. The main motor and the auxiliary motor are both power-connected to the drive shaft. A drive bevel gear B is fixedly connected to the drive shaft. A drive bevel gear B is fixedly connected to the transmission shaft and is meshed with the drive bevel gear B.

[0027] On the basis of the above technical solutions, in order to ensure that the main motor and the auxiliary motor can stably transmit power to the drive shaft when running alone, and will not interfere with the motor in the stopped state, the following technical solutions are provided:

[0028] The main motor and the auxiliary motor are both poweredly connected to a ratchet mechanism that is arranged in the same direction, the ratchet mechanism comprising an inner ratchet, a mounting shaft, and a pawl, the inner ratchet is rotatably mounted on the mounting pad, a driving spur gear is fixedly connected to the periphery of the inner ratchet, a transmission spur gear that is meshed with the driving spur gear is fixedly connected to the driving shaft, the mounting shaft is poweredly connected to the main motor and the auxiliary motor, a pawl is rotatably mounted on the periphery of the mounting shaft, and the pawl is meshed with the corresponding inner ratchet.

[0029] According to the technical solution provided above, a liquid hydrogen delivery method is also provided, comprising the following steps:

[0030] S1, thermally insulate the liquid hydrogen through the transmission pipe, wherein the transmission inner pipe is used to transmit the liquid hydrogen, the thermally insulated outer pipe and the formed vacuum thermal insulation cavity are used to block the liquid hydrogen from the external environment temperature, so as to realize the stable transmission of liquid hydrogen under low temperature;

[0031] S2, continuously pressurizing the liquid hydrogen transmitted in the transmission pipe through the pressurizing part, and cooling the liquid hydrogen transmitted in the transmission pipe through the refrigeration part to ensure that the liquid hydrogen is maintained in a liquid phase and transmitted stably;

[0032] S3, the power is transmitted to the pressurizing part and the refrigeration part through the power part through the transmission part to drive the pressurizing part and the refrigeration part to operate stably; the main motor and the auxiliary motor in the power part are connected to the power of the transmission part to provide power redundancy.

[0033] Beneficial effects of the present invention:

[0034] 1. Effectively maintain the low temperature environment of liquid hydrogen. The innovatively designed liquid hydrogen evenly distributed assembly uses spiral isolation plates to separate the liquid hydrogen flow area, which can effectively extend the flow time of liquid hydrogen in the refrigeration area, ensure that the liquid hydrogen is fully in contact with the refrigeration unit during transportation, and achieve good heat exchange effects. The smooth transition section of the guide column can ensure that the liquid hydrogen is evenly distributed to each spiral flow area, avoiding liquid hydrogen gasification or unstable transmission due to uneven temperature, thereby ensuring the stable transportation of liquid hydrogen in a low temperature environment. This design greatly improves the heat management effect during the liquid hydrogen transportation process and ensures the uniformity and stability of the liquid hydrogen temperature.

[0035] 2. Improve the efficiency of pressurization and refrigeration. By designing a combination of a multi-stage centrifugal pump and a magnetic coupler, not only is the pressurization effect of liquid hydrogen guaranteed during the flow process, but the non-contact transmission method of the magnetic coupler is also used to effectively reduce energy loss and mechanical wear, and improve the operating stability and life of the system. The combination of the cold source sleeve and the heat source sleeve ensures efficient heat exchange between liquid hydrogen and the refrigeration system. In particular, the heat transfer between the cold source and the heat source is more efficient, making the refrigeration effect of liquid hydrogen more significant, and being able to quickly reduce the temperature of liquid hydrogen and avoid liquid hydrogen gasification.

[0036] 3. Redundant design of the power system ensures stable operation of the system. By designing a redundant power system for the main motor and the auxiliary motor, it is ensured that when the main motor fails, the auxiliary motor can quickly intervene and maintain power transmission, ensuring that the liquid hydrogen transport device can continue to operate stably. The introduction of the ratchet mechanism prevents the main motor and the auxiliary motor from interfering with each other when working alone, avoiding mutual interference between the motors or power transmission failures. The redundant design effectively solves the problem of single-point failure in power transmission, improves the reliability of the device, reduces system downtime caused by single motor failure, and improves the overall safety and stability of the liquid hydrogen transport device.

[0037] 4. Effectively improve the thermal insulation effect of liquid hydrogen transportation. By designing a vacuum insulation layer for the transportation pipe, pressurization part and refrigeration part, it can effectively block the heat exchange between the external ambient temperature and the liquid hydrogen to ensure that the liquid hydrogen always operates stably at an extremely low temperature.

[0038] In summary, this solution significantly improves the performance of the liquid hydrogen transportation device. It can not only more effectively maintain the low-temperature environment of liquid hydrogen, but also ensure that the liquid hydrogen is fully pressurized and cooled during the transportation process, while ensuring redundant power intervention in the event of a failure of the device. It has obvious technical advantages and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the present invention;

[0040] Figure 2 It is a structural schematic diagram of another perspective of the present invention;

[0041] Figure 3 It is a structural schematic diagram of the matching combination of two adjacent sections of conveying pipes;

[0042] Figure 4 It is a structural schematic diagram of the combination of the delivery pipe and the temperature insulation ring seat;

[0043] Figure 5 It is a schematic diagram of the internal structure of the pressurizing part;

[0044] Figure 6 for Figure 5 A schematic diagram of the structure from another perspective;

[0045] Figure 7 It is a structural diagram of the matching combination of the refrigeration unit and the conveying pipe;

[0046] Figure 8 for Figure 7 A schematic diagram of the structure from another perspective;

[0047] Fig. 9 It is a schematic diagram of the structure of the refrigeration unit in a cutaway state;

[0048] Fig.10 It is a structural diagram of the sleeve structure matching combination in the refrigeration unit;

[0049] Fig.11 It is a structural schematic diagram of a liquid hydrogen equal distribution component;

[0050] Fig.12 It is a structural schematic diagram of the matching combination of the inner annular piston, the outer annular piston and the crankshaft in the refrigeration unit;

[0051] Fig.13 It is a structural diagram of the combination of the power unit and the transmission unit;

[0052] Fig.14 It is a structural schematic diagram of the matching combination of the ratchet mechanism and the drive shaft;

[0053] Fig.15 Detailed schematic diagram of some structures in the ratchet mechanism.

[0054] In the figure: 1 delivery pipe, 11 transmission inner pipe, 12 insulation outer pipe, 121 connection cover A, 122 connection cover B, 13 vacuum insulation chamber, 2 pressurizing part, 21 insulation cover, 211 connection pipe, 22 multistage centrifugal pump, 221 inlet end, 222 outlet end, 223 main shaft, 224 magnetic coupler output end, 3 refrigeration part, 31 liquid hydrogen equal distribution component, 311 guide column, 312 spiral isolation plate, 32 inner connection sleeve, 321 connection ring seat A, 33 cold source sleeve, 331 inner compression chamber, 332 inner annular piston, 333 limit ring seat, 334 inner connection bracket, 335 guide shaft, 34 outer connection sleeve, 341 connection ring seat B, 35 heat source sleeve, 351 outer compression chamber, 352 outer annular piston, 353 heat sink, 354 outer connection bracket, 355 guide sleeve, 36 connecting pipe, 37 crankshaft, 371 transmission bevel gear A, 38 connecting rod mechanism, 381 connecting rod A, 382 connecting rod B, 4 power unit, 41 main motor, 42 auxiliary motor, 43 driving shaft, 431 driving bevel gear B, 432 transmission spur gear, 44 ratchet mechanism, 441 inner ratchet, 442 mounting shaft, 443 pawl, 444 driving spur gear, 445 leaf spring, 5 transmission unit, 51 transmission shaft, 52 driving bevel gear A, 53 magnetic coupler input end, 54 transmission bevel gear B, 6 mounting pad, 61 thermal insulation pad, 71 flange A, 711 inner connecting port, 72 flange B, 73 thermal insulation ring seat, 731 outer connecting port, 732 nesting groove, 733 nesting ring, 741 sealing rubber ring A, 742 sealing rubber ring B. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Example 1

[0057] See also Figure 1-Figure 2 , Figure 9-10 A liquid hydrogen transportation device includes a transportation pipe 1 connecting the starting point and the end point of liquid hydrogen transportation, and a pressurizing part 2 and a refrigeration part 3 assembled on the transportation pipe 1, and also includes a power part 4 and a transmission part 5. The power part 4 is connected to the pressurizing part 2 and the refrigeration part 3 through the transmission part 5.

[0058] The conveying pipe 1 comprises a transmission inner pipe 11 and a thermal insulation outer pipe 12 sleeved on the outer side of the transmission inner pipe 11 , and a vacuum thermal insulation cavity 13 is provided between the thermal insulation outer pipe 12 and the transmission inner pipe 11 .

[0059] The refrigeration part 3 includes a liquid hydrogen equal distribution component 31, an inner connecting sleeve 32, a cold source sleeve 33, an outer connecting sleeve 34, and a heat source sleeve 35 which are arranged concentrically from the inside to the outside. The inner connecting sleeve 32 is sealedly connected to the transmission inner tube 11, the outer connecting sleeve 34 is sealedly connected to the insulation outer tube 12, the inner connecting sleeve 32 and the cold source sleeve 33 are fixedly connected to form an inner compression chamber 331, and the outer connecting sleeve 34 and the heat source sleeve 35 are fixedly connected to form an outer compression chamber 351.

[0060] The refrigeration unit 3 also includes an inner annular piston 332, an outer annular piston 352, a connecting pipe 36, a crankshaft 37, and a connecting rod mechanism 38. The inner annular piston 332 and the outer annular piston 352 are respectively assembled in the inner compression chamber 331 and the outer compression chamber 351. The connecting pipe 36 is connected with the inner compression chamber 331 and the outer compression chamber 351. The crankshaft 37 is dynamically connected with the transmission unit 5 and the connecting rod mechanism 38. The connecting rod mechanism 38 is linked with the inner annular piston 332 and the outer annular piston 352.

[0061] Liquid hydrogen is transported from the starting point to the end point through the transmission inner tube 11 of the transmission pipe 1. Since the boiling point of hydrogen is about -252.87°C, liquid hydrogen needs to be stably transmitted at extremely low temperatures. Therefore, the added insulation outer tube 12 and the formed vacuum insulation cavity 13 can effectively prevent external heat from affecting the temperature change of liquid hydrogen, thereby ensuring the stable transportation of liquid hydrogen.

[0062] The refrigeration unit 3 can continuously refrigerate the liquid hydrogen during the transportation process to ensure that the liquid hydrogen is maintained within an appropriate temperature range, thereby achieving stable transportation of the liquid hydrogen.

[0063] The pressurizing part 2 can pressurize the transported liquid hydrogen to a specific pressure range to ensure that the liquid hydrogen can be stably transmitted in the transmission inner tube 11, while preventing the liquid hydrogen from gasifying during the transmission process and affecting its stability.

[0064] The power unit 4 can provide continuous and stable power, and stably transmit the power to the pressure unit and the refrigeration unit 3 through the transmission unit 5 to drive the pressure unit and the refrigeration unit 3 to operate stably.

[0065] The refrigeration unit 3 adopts the Stirling refrigeration principle, and drives the crankshaft 37 to operate through the transmission unit 5, and then the connecting rod mechanism 38 drives the inner annular piston 332 and the outer annular piston 352 to reciprocate in the inner compression chamber 331 and the outer compression chamber 351. A metal mesh filler is installed in the connecting pipe 36, which can be used as a heat accumulator. When the fluid medium passes through the metal mesh filler in the connecting pipe 36, it can absorb heat from it or release heat to it.

[0066] In the initial state, the outer annular piston 352 is at the outer end of the outer compression chamber 351, and the inner annular piston 332 is at the inner end of the inner compression chamber 331. When the connecting rod mechanism 38 drives it to operate, the outer annular piston 352 moves inward, while the inner annular piston 332 remains stationary. At this time, the internal gas medium (hydrogen or helium is used as the medium) is compressed and the pressure increases, but the outer wall of the heat source sleeve 35 dissipates heat, resulting in the gas temperature cannot be increased synchronously. This process is isothermal compression and releases heat to the outside through the heat source sleeve 35.

[0067] Afterwards, the connecting rod mechanism 38 drives the outer annular piston 352 to continue to move toward the inner end, while the inner annular piston 332 moves toward the outer end. The gas medium passes through the connecting tube 36 and is absorbed by the metal wire mesh filler therein, and the temperature and pressure are reduced. Then, the inner annular piston 332 continues to move to the outer end. During this process, the gas volume expands, and the temperature and pressure are reduced. However, at this time, the gas continuously absorbs heat from the inner connecting sleeve 32, and the gas expands isothermally and absorbs heat through the inner connecting sleeve 32.

[0068] Finally, the connecting rod mechanism 38 drives the outer annular piston 352 to move toward the outer end, and drives the inner annular piston 332 to move toward the inner end, so that the gas passes through the metal mesh filler in the connecting pipe 36 again. At this time, the volume of the gas remains unchanged, but the temperature and pressure both increase after absorbing heat, completing a reverse Stirling cycle.

[0069] In the above cycle, the inner compression chamber 331 formed by the cold source sleeve 33 and the inner connecting sleeve 32 continuously absorbs heat from the gas medium, thereby reducing the temperature of the liquid hydrogen evenly distributed in the liquid hydrogen distribution component 31, while the outer compression chamber 351 formed by the heat source sleeve 35 and the outer connecting sleeve 34 continuously absorbs heat from the gas medium and dissipates it to the environment. Therefore, the inner compression chamber 331 forms a cold end to refrigerate the liquid hydrogen.

[0070] Example 2

[0071] See also Figure 1-Figure 6 In order to ensure that the pressurizing unit 2, the refrigeration unit 3, the power unit 4, and the transmission unit 5 can be stably installed and matched, and to ensure that the pressurizing unit 2 can continuously pressurize the transmitted liquid hydrogen and avoid the external heat from exchanging heat with the transmitted liquid hydrogen through the pressurizing unit 2, resulting in the temperature of the liquid hydrogen rising, the following technical solutions are provided:

[0072] It also includes a mounting seat 6 , on which the pressurizing part 2 , the refrigeration part 3 , the power part 4 , and the transmission part 5 are all assembled.

[0073] The pressurizing part 2 includes a thermal insulation cover 21 and a multistage centrifugal pump 22 arranged on the inner side of the thermal insulation cover 21. The thermal insulation cover 21 and the multistage centrifugal pump 22 are both fixedly mounted on the mounting pad 6. The inlet end 221 and the outlet end 222 of the multistage centrifugal pump 22 are both sealedly connected to the transmission inner tube 11. The thermal insulation cover 21 is connected to a connecting pipe 211 arranged on the periphery of the inlet end 221 and the outlet end 222. The connecting pipe 211 is sealedly connected to the thermal insulation outer tube 12.

[0074] The arrangement of the mounting pad 6 can ensure that the pressurizing part 2, the refrigeration part 3, the power part 4, and the transmission part 5 are stably mounted thereon and realize the matching combination of each component, so as to realize the stable transmission, refrigeration, and pressurization operation of liquid hydrogen.

[0075] The thermal insulation cover 21 is connected to the thermal insulation outer tube 12 through the connecting pipe 211 thereon, so as to realize the connection between the vacuum insulation cavity 13 and the thermal insulation cover 21. After evacuating the cover, a vacuum environment can be formed between the thermal insulation cover 21 and the multi-stage centrifugal pump 22, thereby blocking the transmission path of external heat to the multi-stage centrifugal pump 22 and preventing the liquid hydrogen from being disturbed by the external ambient temperature during the pressurization process.

[0076] A thermal insulation pad 61 is detachably mounted on the mounting pad 6 , and the housing of the multi-stage centrifugal pump 22 is fixedly mounted on the thermal insulation pad 61 . The thermal insulation pad 61 can effectively isolate heat transfer and prevent external heat from being transferred to the multi-stage centrifugal pump 22 through the mounting pad 6 .

[0077] In order to ensure that each section of the delivery pipe 1 can be stably connected, to ensure that the delivery pipe 1 can be stably connected to the pressurizing part 2, and to ensure the heat insulation effect during the liquid hydrogen transmission process, the following technical solutions are provided:

[0078] The ends of the transmission inner tube 11, the inlet end 221, and the outlet end 222 are all fixedly connected with flanges A71, and the ends of the insulation outer tube 12 and the connecting tube 211 are all fixedly connected with flanges B72. An insulation ring seat 73 is nested between flanges A71 and flange B72. The outer edge of flange A71 is nested into the inner edge of the insulation ring seat 73 and fixedly combined by a bolt assembly. The outer edge of the insulation ring seat 73 is nested between the two groups of flanges B72 and fixedly combined by a bolt assembly. The insulation ring seat 73 and the flange A71 are respectively provided with an external connecting port 731 and an internal connecting port 711.

[0079] A nesting groove 732 is provided at the inner edge of the thermal insulation ring seat 73, which can ensure that two sets of closely arranged flanges A71 are stably installed in the nesting groove 732 and fixedly combined by a bolt assembly. The outer edge of the thermal insulation ring seat 73 is kept in contact with the inner wall of the connecting pipe 211 or the thermal insulation outer tube 12, and the outer wall of the thermal insulation ring seat 73 is fixedly connected with a nesting ring 733 that is kept in contact with the flange B72, and is fixedly combined by a bolt assembly.

[0080] The external connecting port 731 and the internal connecting port 711 can ensure the connection between the vacuum insulation chamber 13 and the thermal insulation cover 21, and facilitate the extraction of the internal air through a vacuum pump to form a vacuum isolation zone surrounding the periphery of the liquid hydrogen transmission path, thereby ensuring the thermal insulation effect.

[0081] A sealing rubber ring A741 is provided between two adjacent groups of flanges A71 to ensure the sealing effect of the two adjacent groups of transmission inner tubes 11 and the connection position of the transmission inner tube 11 at the inlet end 221 or the outlet end 222. A sealing rubber ring B742 is provided on both sides of the nesting ring 733. The sealing rubber ring B742 maintains a sealing fit with the nesting ring 733 and the flange B72 to ensure the airtight effect of the vacuum insulation chamber 13.

[0082] Example 3

[0083] See also Figure 7-Figure 12 In order to ensure that the components in the refrigeration unit 3 can be matched and combined, and to achieve effective refrigeration of liquid hydrogen, the following technical solutions are provided:

[0084] The liquid hydrogen equal distribution component 31 includes a guide column 311 and a spiral isolation plate 312 fixed to the periphery of the guide column 311 and maintained evenly distributed, the spiral isolation plate 312 is fixedly connected to the inner connecting sleeve 32, the inner connecting sleeve 32 is fixedly connected to the cold source sleeve 33 via a connecting ring seat A321, the outer connecting sleeve 34 is fixedly connected to the heat source sleeve 35 via a connecting ring seat B341, and heat sinks 353 are evenly fixed on the outer wall of the heat source sleeve 35.

[0085] Each spiral isolation plate 312 can separate the space between the guide column 311 and the inner connecting sleeve 32 into a plurality of spiral flow areas, and both ends of the guide column 311 are arranged as smooth arc-shaped transition sections, which can ensure that the transmitted liquid hydrogen is distributed to each spiral flow area through the arc-shaped transition section, and contacts with the inner connecting sleeve 32, so as to realize effective refrigeration of the liquid hydrogen passing through each spiral flow area, and the setting of the spiral flow area can also effectively prolong the flow time of liquid hydrogen therein, so as to ensure the refrigeration and heat exchange effect.

[0086] The setting of the connecting ring seat A321 can realize the fixed connection between the inner connecting sleeve 32 and the cold source sleeve 33, while the setting of the connecting ring seat B341 can realize the fixed connection between the outer connecting sleeve 34 and the heat source sleeve 35, and the setting of the heat sink 353 can effectively dissipate the heat of the outer compression chamber 351 to the external environment.

[0087] The two ends of the outer compression chamber 351 are respectively fixed with a connecting cover A121 and a connecting cover B122. The connecting cover A121 and the connecting cover B122 are fixedly connected to the end of the thermal insulation outer tube 12. The connecting cover A121 is fixedly connected to the ends of the external connecting sleeve 34 and the heat source sleeve 35, and the connecting cover B122 is fixedly connected to the connecting ring seat B341. The connecting pipe 36 and the connecting cover B122 are sealed and plugged in, and the two ends of the connecting pipe 36 are respectively connected to the connecting ring seat A321 and the heat source sleeve 35.

[0088] The connecting cover A121 and the connecting cover B122 are assembled to the two ends of the compression chamber by bolting, and a sealing rubber ring is provided at the connecting part to ensure the sealing effect of the connecting combination. The connecting cover A121 and the connecting cover B122 are respectively welded to the insulating outer tube 12 located at the two ends of the refrigeration part 3.

[0089] The diameter of the inner connecting sleeve is larger than that of the transmission inner tube 11, so the inner connecting sleeve 32 is provided with a transition section with a wide end and a narrow inner side at the transmission inner tube 11 connected at both ends, so as to achieve effective connection with the transmission inner tube 11 and ensure stable transmission of liquid hydrogen. One end of the inner connecting sleeve 32 provided with a connecting ring seat A321 is fixedly connected to the corresponding transmission inner tube 11 through a bolt assembly, and the other end is fixedly connected to the corresponding transmission inner tube 11 through welding. In this way, the effective combination of the components of the refrigeration unit 3 and the effective connection with the transmission pipes 1 at both ends are achieved.

[0090] A limiting ring seat 333 is also fixedly connected to the end of the cold source sleeve 33 to effectively limit the position of the inner annular piston 332 assembled inside the cold source sleeve 33 .

[0091] In order to ensure that the crankshaft 37 can drive the inner annular piston 332 and the outer annular piston 352 to operate stably through the connecting rod mechanism 38, the following technical solutions are provided:

[0092] The inner annular piston 332 and the outer annular piston 352 are respectively fixed with an inner connecting bracket 334 and an outer connecting bracket 354, which are both sealed and plugged with the connecting cover A121. The inner connecting bracket 334 and the outer connecting bracket 354 are respectively fixed to the guide shaft 335 and the guide sleeve 355, which are slidably plugged with the guide shaft 335 and the guide sleeve 355.

[0093] The connecting rod mechanism 38 includes a connecting rod A381 and a connecting rod B382. Both the connecting rod A381 and the connecting rod B382 are hinged to the crankshaft 37. The guide shaft 335 is hinged to the connecting rod A381. The guide sleeve 355 is hinged to the connecting rod B382.

[0094] When the crankshaft 37 is running, it can drive the guide shaft 335 and the guide sleeve 355 to slide back and forth stably along the axial direction through the connecting rod A381 and the connecting rod B382. The sliding combination of the guide sleeve 355 and the guide shaft 335 can ensure that both can realize independent movement along the same axis, thereby driving the inner annular piston 332 and the outer annular piston 352 to operate stably along the set regulations.

[0095] In order to avoid spatial movement interference between the inner connecting bracket 334 and the outer connecting bracket 354 extending to the outside of the refrigeration part 3 and the conveying pipe 1, the conveying pipe 1 on the side of the inner connecting bracket 334 and the outer connecting bracket 354 is set to a bending structure, while ensuring that the axis of the pressurizing part 2 and the axis of the refrigeration part 3 remain vertically distributed.

[0096] Example 4

[0097] See also Figure 1-Figure 2 , Figure 13-Figure 15 In order to ensure that the transmission part 5 can be stably installed on the mounting pad 6 and that the transmission part 5 can drive the multi-stage centrifugal pump 22 and the crankshaft 37 to operate stably, the following technical solutions are provided:

[0098] The transmission part 5 includes a transmission shaft 51 to drive a driving bevel gear A52 on the transmission shaft 51, and a magnetic coupling input end 53. The transmission shaft 51 is rotatably mounted on the mounting pad 6 and is coaxially arranged with the main shaft 223 of the multistage centrifugal pump 22. The main shaft 223 of the multistage centrifugal pump 22 is fixedly connected with a magnetic coupling output end 224 arranged on the inner side of the thermal insulation cover 21. The magnetic coupling input end 53 and the magnetic coupling output end 224 are relatively arranged. The crankshaft 37 is rotatably mounted on the mounting pad 6, and the end of the crankshaft 37 is fixedly connected with a transmission bevel gear A371 that is meshed with the driving bevel gear A52.

[0099] When the transmission shaft 51 is running, it can drive the driving bevel gear A52 and the magnetic coupling input end 53 thereon to run stably, and then drive the crankshaft 37 to run stably through the transmission bevel gear A371, and drive the main shaft 223 to run stably through the magnetic coupling output end 224, so as to realize the stable operation of the multi-stage centrifugal pump 22.

[0100] In order to ensure that the power of the driving unit can be stably transmitted to the transmission shaft 51 and to provide power redundancy when a device fails, the following technical solutions are provided:

[0101] The power unit 4 includes a main motor 41, an auxiliary motor 42 and a drive shaft 43. The main motor 41 and the auxiliary motor 42 are fixedly mounted on the mounting pad 6. The drive shaft 43 is rotatably mounted on the mounting pad 6. The main motor 41 and the auxiliary motor 42 are both poweredly connected to the drive shaft 43. A drive bevel gear B431 is fixedly connected to the drive shaft 43. A drive bevel gear B54 is fixedly connected to the drive shaft 51 and is meshed with the drive bevel gear B431.

[0102] When the main motor 41 and the auxiliary motor 42 rotate, they can drive the drive shaft 43 to operate stably, and then drive the transmission shaft 51 to operate stably through the combination of the driving bevel gear B431 and the transmission bevel gear B54. Under normal conditions, the main motor 41 works alone and transmits power to the transmission shaft 51 through the drive shaft 43. When the main motor 41 fails, the auxiliary motor 42 works to drive the transmission shaft 51 to operate stably through the drive shaft 43.

[0103] In order to ensure that the main motor 41 and the auxiliary motor 42 can stably transmit power to the drive shaft 43 when running alone and will not interfere with the motor in the stopped state, the following technical solutions are provided:

[0104] The main motor 41 and the auxiliary motor 42 are both poweredly connected to a ratchet mechanism 44 that is arranged in the same direction. The ratchet mechanism 44 includes an inner ratchet 441, a mounting shaft 442, and a pawl 443. The inner ratchet 441 is rotatably mounted on the mounting pad 6. A driving spur gear 444 is fixedly connected to the periphery of the inner ratchet 441. A transmission spur gear 432 that is meshed with the driving spur gear 444 is fixedly connected to the driving shaft 43. The mounting shaft 442 is poweredly connected to the main motor 41 and the auxiliary motor 42. A pawl 443 is rotatably mounted on the periphery of the mounting shaft 442, and the pawl 443 is meshed with the corresponding inner ratchet 441.

[0105] The mounting shaft 442 is also provided with a leaf spring 445 which is in contact with the corresponding ratchet 443 . The leaf spring 445 can ensure that the ratchet 443 always expands outward and keeps meshing with the corresponding inner ratchet 441 .

[0106] Since the two sets of driving spur gears 444 are meshed with the transmission spur gear 432, the two sets of driving spur gears 444 and the inner ratchet 441 always run in the same direction and at the same speed. When the main motor 41 drives the installation shaft 442 and the ratchet 443 connected thereto to run, the ratchet 443 can drive the corresponding inner ratchet 441 and driving spur gear 444 to run stably, and then drive the driving spur gear 444 connected to the auxiliary motor 42 to run synchronously through the transmission spur gear 432. Since the handle transmits power to the corresponding ratchet 443 and the installation shaft 442 when the driving spur gear 444 and the inner ratchet 441 associated with the auxiliary motor 42 are running, there is no interference with the auxiliary motor 42. When the auxiliary motor 42 runs independently, it will not interfere with the main motor 41 either.

[0107] Example 5

[0108] See also Figure 1-Figure 2 According to the technical solution provided above, a liquid hydrogen delivery method is also provided, comprising the following steps:

[0109] S1, liquid hydrogen is thermally insulated and transmitted through the transmission pipe 1, wherein the transmission inner pipe 11 is used to transmit liquid hydrogen, the insulation outer pipe 12 and the formed vacuum insulation cavity 13 are used to block the liquid hydrogen from the external environment temperature, so as to realize the stable transmission of liquid hydrogen under low temperature;

[0110] S2, continuously pressurizing the liquid hydrogen transmitted in the delivery pipe 1 through the pressurizing unit 2, and cooling the liquid hydrogen transmitted in the delivery pipe 1 through the refrigeration unit 3 to ensure that the liquid hydrogen is maintained in a liquid phase and is stably transmitted;

[0111] S3, the power is transmitted to the pressurizing part 2 and the refrigerating part 3 through the power part 4 via the transmission part 5, so as to drive the pressurizing part 2 and the refrigerating part 3 to operate stably; the main motor 41 and the auxiliary motor 42 in the power part 4 are both connected to the transmission part 5 to provide power redundancy.

[0112] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should all be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0113] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A liquid hydrogen delivery device, characterized in that: It comprises a delivery pipe (1) connecting the starting point and the end point of liquid hydrogen delivery, and a pressurizing part (2) and a refrigeration part (3) assembled on the delivery pipe (1), and also comprises a power part (4) and a transmission part (5), wherein the power part (4) is connected to the pressurizing part (2) and the refrigeration part (3) by power through the transmission part (5); The transport pipe (1) comprises a transport inner pipe (11) and a thermal insulation outer pipe (12) sleeved onto the outside of the transport inner pipe (11), wherein a vacuum thermal insulation cavity (13) is provided between the thermal insulation outer pipe (12) and the transport inner pipe (11); The refrigeration part (3) comprises a liquid hydrogen equal distribution component (31), an inner connecting sleeve (32), a cold source sleeve (33), an outer connecting sleeve (34), and a heat source sleeve (35) which are arranged concentrically from the inside to the outside, the inner connecting sleeve (32) is sealedly connected to the transmission inner tube (11), the outer connecting sleeve (34) is sealedly connected to the insulation outer tube (12), the inner connecting sleeve (32) and the cold source sleeve (33) are fixedly connected to form an inner compression chamber (331), and the outer connecting sleeve (34) and the heat source sleeve (35) are fixedly connected to form an outer compression chamber (351); The refrigeration part (3) further comprises an inner annular piston (332), an outer annular piston (352), a connecting pipe (36), a crankshaft (37), and a connecting rod mechanism (38); the inner annular piston (332) and the outer annular piston (352) are respectively assembled into the inner compression chamber (331) and the outer compression chamber (351); the connecting pipe (36) is connected with the inner compression chamber (331) and the outer compression chamber (351); the crankshaft (37) is dynamically connected with the transmission part (5) and the connecting rod mechanism (38); and the connecting rod mechanism (38) is linked with the inner annular piston (332) and the outer annular piston (352).

2. A liquid hydrogen delivery device according to claim 1, characterized in that: It also includes a mounting seat (6), and the pressurizing part (2), the refrigeration part (3), the power part (4), and the transmission part (5) are all assembled on the mounting seat (6); The pressurizing portion (2) comprises a thermal insulation cover (21) and a multistage centrifugal pump (22) arranged inside the thermal insulation cover (21); the thermal insulation cover (21) and the multistage centrifugal pump (22) are both fixedly mounted on the mounting pad (6); the inlet end (221) and the outlet end (222) of the multistage centrifugal pump (22) are both sealedly connected to the transmission inner tube (11); the thermal insulation cover (21) is connected to a connecting pipe (211) arranged outside the inlet end (221) and the outlet end (222); and the connecting pipe (211) is sealedly connected to the thermal insulation outer tube (12).

3. A liquid hydrogen delivery device according to claim 2, characterized in that: The end of the transmission inner tube (11), the inlet end (221), and the outlet end (222) are all fixedly connected to a flange A (71); the end of the thermal insulation outer tube (12) and the connecting tube (211) are all fixedly connected to a flange B (72); a thermal insulation ring seat (73) is nested between the flange A (71) and the flange B (72); the outer edge of the flange A (71) is nested into the inner edge of the thermal insulation ring seat (73) and fixedly assembled by a bolt assembly; the outer edge of the thermal insulation ring seat (73) is nested between the two groups of flanges B (72) and fixedly assembled by a bolt assembly; the thermal insulation ring seat (73) and the flange A (71) are respectively provided with an external communication port (731) and an internal communication port (711).

4. A liquid hydrogen delivery device according to claim 2, characterized in that: The liquid hydrogen equal distribution component (31) comprises a guide column (311) and a spiral isolation plate (312) fixedly connected to the periphery of the guide column (311) and maintained in uniform distribution, the spiral isolation plate (312) being fixedly connected to the inner connecting sleeve (32), the inner connecting sleeve (32) being fixedly connected to the cold source sleeve (33) via a connecting ring seat A (321), the outer connecting sleeve (34) being fixedly connected to the hot source sleeve (35) via a connecting ring seat B (341), and a heat sink (353) being evenly fixedly connected to the outer wall of the hot source sleeve (35); A connecting cover A (121) and a connecting cover B (122) are fixed to the two ends of the outer compression chamber (351), respectively. The connecting cover A (121) and the connecting cover B (122) are both fixedly connected to the end of the thermal insulation outer tube (12). The connecting cover A (121) is fixedly connected to the ends of the outer connecting sleeve (34) and the heat source sleeve (35), and the connecting cover B (122) is fixedly connected to the connecting ring seat B (341). The connecting pipe (36) and the connecting cover B (122) are sealed and plugged together, and the two ends of the connecting pipe (36) are respectively connected to the connecting ring seat A (321) and the heat source sleeve (35).

5. A liquid hydrogen delivery device according to claim 4, characterized in that: An inner connecting bracket (334) and an outer connecting bracket (354) are fixedly connected to the inner annular piston (332) and the outer annular piston (352), respectively. The inner connecting bracket (334) and the outer connecting bracket (354) are both sealed and plugged with the connecting cover A (121). The inner connecting bracket (334) and the outer connecting bracket (354) are respectively fixedly connected to a guide shaft (335) and a guide sleeve (355). The guide shaft (335) and the guide sleeve (355) are slidably plugged. The connecting rod mechanism (38) comprises a connecting rod A (381) and a connecting rod B (382); the connecting rod A (381) and the connecting rod B (382) are both hinged to the crankshaft (37); the guide shaft (335) is hinged to the connecting rod A (381); and the guide sleeve (355) is hinged to the connecting rod B (382).

6. A liquid hydrogen delivery device according to claim 5, characterized in that: The transmission part (5) comprises a transmission shaft (51) for driving a driving bevel gear A (52) on the transmission shaft (51), and a magnetic coupling input end (53); the transmission shaft (51) is rotatably mounted on the mounting seat (6) and is coaxially arranged with a main shaft (223) of the multistage centrifugal pump (22); a magnetic coupling output end (224) arranged on the inner side of the thermal insulation cover (21) is fixedly connected to the main shaft (223) of the multistage centrifugal pump (22); the magnetic coupling input end (53) and the magnetic coupling output end (224) are arranged relative to each other; the crankshaft (37) is rotatably mounted on the mounting seat (6); and a transmission bevel gear A (371) meshing with the driving bevel gear A (52) is fixedly connected to the end of the crankshaft (37).

7. A liquid hydrogen delivery device according to claim 6, characterized in that: The power unit (4) comprises a main motor (41), an auxiliary motor (42) and a drive shaft (43); the main motor (41) and the auxiliary motor (42) are both fixedly mounted on the mounting seat (6); the drive shaft (43) is rotatably mounted on the mounting seat (6); the main motor (41) and the auxiliary motor (42) are both in power connection with the drive shaft (43); a drive bevel gear B (431) is fixedly connected to the drive shaft (43); and a drive bevel gear B (54) is fixedly connected to the drive shaft (51) and is meshed with the drive bevel gear B (431).

8. A liquid hydrogen delivery device according to claim 7, characterized in that: The main motor (41) and the auxiliary motor (42) are both kinetically connected to a ratchet mechanism (44) arranged in the same direction. The ratchet mechanism (44) comprises an inner ratchet (441), a mounting shaft (442), and a ratchet pawl (443). The inner ratchet (441) is rotatably mounted on the mounting pad (6). A driving spur gear (444) is fixedly connected to the periphery of the inner ratchet (441). A transmission spur gear (432) meshing with the driving spur gear (444) is fixedly connected to the driving shaft (43). The mounting shaft (442) is kinetically connected to the main motor (41) and the auxiliary motor (42). A ratchet pawl (443) is rotatably mounted on the periphery of the mounting shaft (442). The ratchet pawl (443) meshes with the corresponding inner ratchet (441).

9. According to any one of claims 1 to 8, a liquid hydrogen delivery device is also provided, characterized in that: The steps include: S1, thermally insulated transmission of liquid hydrogen through a transmission pipe (1), wherein the transmission inner pipe (11) is used to transmit liquid hydrogen, and the thermally insulated outer pipe (12) and the formed vacuum thermal insulation cavity (13) are used to isolate the liquid hydrogen from the external environment temperature, thereby achieving stable transmission of liquid hydrogen under low temperature conditions; S2, continuously pressurizing the liquid hydrogen transported in the transport pipe (1) through the pressurizing unit (2), and cooling the liquid hydrogen transported in the transport pipe (1) through the refrigeration unit (3), so as to ensure that the liquid hydrogen is maintained in a liquid phase and is stably transported; S3, the power is transmitted to the pressurizing part (2) and the refrigerating part (3) through the power part (4) via the transmission part (5), so as to drive the pressurizing part (2) and the refrigerating part (3) to operate stably; the main motor (41) and the auxiliary motor (42) in the power part (4) are both connected to the transmission part (5) to provide power redundancy.

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