Small liquid hydrogen pump for hydrogen refueling station

Abstract

The small liquid hydrogen pump for the hydrogen refueling station comprises a pumping assembly, a conveying assembly and a cooling assembly, the pumping assembly is connected with the conveying assembly, and the cooling assembly is connected with the conveying assembly; the cooling assembly comprises a cooling medium flow channel and a refrigerating machine, the cooling medium flow channel is arranged on the outer wall of the inner pipe in a surrounding mode, and the cooling medium flow channel is provided with a cooling medium inlet and a cooling medium outlet. The heat leakage of the environment is actively counteracted, the temperature of the environment where the inner pipe is located is far lower than that of the environment where the inner pipe is located in a traditional heat insulation mode, evaporation and vaporization of liquid hydrogen are greatly reduced, the conveying efficiency and economical efficiency are improved, the hydrogen generation amount is greatly reduced, the pressure fluctuation in the pipeline is small, and the safety risk caused by overpressure is remarkably reduced. And meanwhile, the dependence on a complex hydrogen gas treatment system is also reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of hydrogen energy storage and transportation equipment, and in particular to a small liquid hydrogen pump for a hydrogen refueling station. BACKGROUND

[0002] As a core carrier of zero-carbon energy, the large-scale application of hydrogen energy relies on efficient, safe storage, transportation and refueling technology. As the terminal node of hydrogen energy supply, hydrogen refueling stations have an urgent need for the miniaturization, low evaporation rate and high stability of liquid hydrogen delivery equipment. The performance of a liquid hydrogen pump, as the core equipment for the pressurized delivery of liquid hydrogen in a hydrogen refueling station, directly determines the hydrogen refueling efficiency, energy consumption and safety.

[0003] In the prior art, the liquid hydrogen pump has the following key defects:

[0004] Insufficient adiabatic performance, high liquid hydrogen evaporation rate:

[0005] The boiling point of liquid hydrogen is extremely low (-252.87 DEG C), and environmental heat intrusion is the main reason for the evaporation of liquid hydrogen. Traditional liquid hydrogen pumps mostly use a single passive adiabatic structure (such as multiple layers of adiabatic materials), which can reduce heat transfer, but residual heat continues to accumulate during long-term operation, resulting in a liquid hydrogen evaporation rate of 3%-5% / h. This not only increases energy consumption, but also may trigger system overpressure protection due to high evaporation pressure, affecting continuous operation.

[0006] Large structure, poor adaptability:

[0007] Existing large liquid hydrogen pumps require a separate external refrigeration unit, and the equipment has a large volume (usually more than 2m x 1m x 1m in length x width x height) and a large weight (more than 300kg), and the pipeline connection is complex, making it difficult to adapt to the space restrictions of small hydrogen refueling stations (such as skid-mounted hydrogen refueling stations) or distributed scenarios (such as hydrogen energy forklift refueling points).

[0008] Insufficient safety and stability:

[0009] During the delivery of liquid hydrogen, the temperature gradient between the inner tube and the outer tube easily generates thermal stress, leading to deformation or sealing failure of the pipeline, and there is a risk of liquid hydrogen leakage; at the same time, the cooling system and the pumping system lack coordinated control, which easily leads to a sharp decrease in pump body efficiency due to local overheating, and even causes mechanical failure.

[0010] High maintenance cost:

[0011] The existing liquid hydrogen pump has low integration of the cooling circuit and the delivery pipeline, the components are complicated to disassemble and assemble, and there is a lack of real-time monitoring means, so the fault troubleshooting time is long (usually more than 4 hours), and the maintenance cost accounts for more than 30% of the total life cycle cost of the equipment.

[0012] Therefore, developing a liquid hydrogen pump with high efficiency, small size, safety, stability and easy maintenance has become a key technical breakthrough for promoting the large-scale application of small hydrogen refueling stations. SUMMARY

[0013] In order to overcome the existing problems, the embodiment of the present application provides a small liquid hydrogen pump for hydrogen refueling station, which aims to overcome the defects of insufficient thermal insulation performance, large structure, low safety and difficult maintenance of the existing liquid hydrogen pump, and provides a small liquid hydrogen pump for hydrogen refueling station, which realizes low evaporation rate delivery, small size adaptation and high reliability operation through passive thermal insulation and active cooling composite protection, modular integration and intelligent collaborative control, and significantly improves the authorization stability.

[0014] The technical scheme adopted by the embodiment of the present application to solve the technical problems is:

[0015] A small liquid hydrogen pump for hydrogen refueling station, comprising a pumping assembly, a conveying assembly and a cooling assembly, the pumping assembly is connected with the conveying assembly, and the cooling assembly is connected with the conveying assembly;

[0016] The conveying assembly comprises an inner tube and an outer tube, the outer tube is sleeved outside the inner tube to form an annular interlayer space between the inner tube and the outer tube, the inner tube is used for conveying liquid hydrogen, and the outer tube is used for protecting the inner tube, the inner tube and the outer tube are concentrically sleeved to form the annular interlayer space, the annular interlayer space is filled with high-vacuum multi-layer thermal insulation material as a thermal insulation layer, and a copper spiral coil pipe is tightly wound on the outer wall of the inner tube as a cooling medium flow channel;

[0017] The cooling assembly comprises a cooling medium flow channel and a refrigerator, the cold end of the refrigerator is coupled with the cooling medium flow channel, and is used for providing low-temperature cooling medium to the cooling medium flow channel, the cooling medium flow channel is arranged around the outer wall of the inner tube, the cooling medium flow channel has a cooling medium inlet and a cooling medium outlet, the cooling medium flow channel, the refrigerator and the pipeline constitute a closed circulation loop, the cooling medium circulates in the loop, continuously taking away the heat around the inner tube, the closed circulation loop is filled with liquid nitrogen as the cooling medium, and when the refrigerator works, the cooling medium is cooled and naturally convects in the loop, continuously absorbs the heat transmitted from the outside when flowing through the spiral coil pipe, so that the outer wall of the inner tube is maintained at an extremely low temperature.

[0018] Preferably, the annular interlayer space is embedded with a thermal insulation layer for actively removing residual heat, the thermal insulation layer is one of high-vacuum multi-layer thermal insulation material, vacuum powder thermal insulation material or aerogel thermal insulation material, the thermal insulation layer is attached to the inner wall of the outer tube, and the inner wall of the thermal insulation layer is attached to the cooling medium flow channel.

[0019] Preferably, the pumping assembly comprises a delivery pump, one end of the delivery pump is provided with a fixed seat, and the output end of the delivery pump is provided with an impeller seat, and the impeller seat is provided with a base away from one end of the delivery pump, and the base is fixedly connected with the fixed seat through a connecting piece.

[0020] Wherein, one side of the impeller seat is provided with an inlet pipe, and the other side is provided with an outlet pipe, the inlet pipe is used for conveying liquid hydrogen into the inside of the impeller seat, and then output from the outlet pipe.

[0021] Preferably, the delivery assembly further comprises a connecting seat connected with the outlet pipe, and a bellows compensator is arranged in the connecting seat, which is used for absorbing the displacement caused by thermal expansion and cold contraction.

[0022] Preferably, the refrigerator is electrically connected with a power supply, and the refrigerator is provided with connecting pipes at both ends, one end of the connecting pipe is connected with the refrigerator, and the other end is connected with the cooling medium inlet and the cooling medium outlet respectively.

[0023] Preferably, the cooling medium flow channel is a spiral coil structure, which is tightly wound on the outer surface of the inner pipe, and the cooling medium flows in the inside.

[0024] Wherein, the cooling medium is one of liquid nitrogen, liquid helium or low-temperature refrigerant, which is used for increasing the heat exchange area and uniform cooling effect.

[0025] Preferably, the outer pipe is provided with a temperature sensor at both ends of the outer wall, the temperature sensor adopts armored platinum resistance, is arranged along the axis of the inner pipe, the measurement range is-270℃ to 50℃, the accuracy is ± 0.05℃, the inner side of the two temperature sensors is provided with a leakage sensor, the leakage sensor is arranged on the inner wall of the outer pipe, adopts hydrogen sensor, and can monitor the liquid hydrogen leakage in real time, the inner wall of the outer pipe is also provided with a radiation shield, the radiation shield is connected with the cold end of the refrigerator, so that the temperature is maintained at a low temperature level, which is used for effectively blocking the radiation heat flow, the radiation shield is sleeved on the outer surface wall of the heat insulation layer, and the radiation shield can play the effect of preventing radiation and protecting the heat insulation layer, thereby prolonging the service life of the heat insulation layer.

[0026] The advantages of the embodiment of the application are:

[0027] 1. A low-temperature barrier is established around the liquid hydrogen delivery pipeline through the active cooling structure, and the environmental heat leakage is actively offset, so that the environmental temperature of the inner pipe is much lower than that of the traditional heat insulation mode, thereby greatly reducing the evaporation and vaporization of liquid hydrogen, improving the delivery efficiency and economy, and significantly reducing the safety risk caused by overpressure due to the significant reduction of hydrogen gas generation, and reducing the dependence on complex hydrogen gas treatment system.

[0028] 2, The advantages of passive insulation and active cooling are combined to form a synergistic composite insulation system, which is especially suitable for long-distance, large-diameter or harsh environment liquid hydrogen transportation. Through sensors and control systems, real-time sensing of thermal load changes and intelligent adjustment of refrigeration power can be realized to avoid energy waste and achieve efficient and energy-saving operation. BRIEF DESCRIPTION OF DRAWINGS

[0029] The application will be further described below in conjunction with the drawings and examples.

[0030] Figure 1 The overall structure of the small liquid hydrogen pump for hydrogenation station of the application is shown in the figure;

[0031] Figure 2 The overall structure of the pumping assembly in the small liquid hydrogen pump for hydrogenation station of the application is shown in the figure;

[0032] Figure 3 The overall structure of the outer tube and the insulation layer in the conveying assembly in the small liquid hydrogen pump for hydrogenation station of the application is shown in the figure;

[0033] Figure 4 The overall structure of the outer tube and the radiation protection screen in the conveying assembly in the small liquid hydrogen pump for hydrogenation station of the application is shown in the figure;

[0034] Figure 5 The overall structure of the cooling assembly in the small liquid hydrogen pump for hydrogenation station of the application is shown in the figure.

[0035] Main figure mark explanation:

[0036] 100, Pumping assembly;

[0037] 11, Conveying pump; 12, Fixed seat; 13, Inlet pipe; 14, Outlet pipe; 15, Base; 16, Impeller seat;

[0038] 200, Conveying assembly;

[0039] 21, Outer tube; 22, Inner tube; 23, Insulation layer; 24, Connection seat; 25, Temperature sensor; 26, Leakage sensor; 27, Radiation protection screen;

[0040] 300, Cooling assembly;

[0041] 31, Refrigerator; 32, Connection pipe; 33, Cooling medium inlet; 34, Cooling medium outlet; 35, Cooling medium flow channel. DETAILED DESCRIPTION

[0042] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. In addition, for the convenience of description, the terms "upper", "lower", "left", "right" and the like in the following description are consistent with the directions of "upper", "lower", "left", "right" and the like in the drawings, and the terms "first", "second" and the like in the following description are used only for differentiation, and have no other special meanings.

[0043] The embodiment of the present application provides a small liquid hydrogen pump for hydrogen refueling station, solves the problems in the prior art, establishes a low-temperature barrier outside a liquid hydrogen conveying pipeline through an active cooling structure, actively offsets environmental heat leakage, makes the environmental temperature of an inner tube far lower than that in a conventional adiabatic mode, thereby greatly reducing evaporation and vaporization of liquid hydrogen, and improving conveying efficiency and economy. Since the amount of generated hydrogen gas is greatly reduced, the pressure fluctuation in the pipeline is small, the safety risk caused by overpressure is significantly reduced, and the dependence on a complex hydrogen gas treatment system is also reduced.

[0044] The embodiment of the present application provides a small liquid hydrogen pump for hydrogen refueling station, solves the problems in the prior art, establishes a low-temperature barrier outside a liquid hydrogen conveying pipeline through an active cooling structure, actively offsets environmental heat leakage, makes the environmental temperature of an inner tube far lower than that in a conventional adiabatic mode, thereby greatly reducing evaporation and vaporization of liquid hydrogen, and improving conveying efficiency and economy. Since the amount of generated hydrogen gas is greatly reduced, the pressure fluctuation in the pipeline is small, the safety risk caused by overpressure is significantly reduced, and the dependence on a complex hydrogen gas treatment system is also reduced.

[0045] The technical solutions in the embodiments of the present application are as follows:

[0046] Embodiment one

[0047] The embodiment provides a specific structure of a small liquid hydrogen pump for hydrogen refueling station, as shown in Figures 1-5 The embodiment provides a specific structure of a small liquid hydrogen pump for hydrogen refueling station, as shown in

[0048] The conveying assembly 200 comprises an inner tube 22 and an outer tube 21, the outer tube 21 is sleeved outside the inner tube 22 to form an annular interlayer space between the inner tube 22 and the outer tube 21, the inner tube 22 is used for conveying liquid hydrogen, the outer tube 21 is used for protecting the inner tube 22, the inner tube 22 and the outer tube 21 are concentrically sleeved to form the annular interlayer space, the annular interlayer space is filled with high-vacuum multi-layer thermal insulation material as a thermal insulation layer 23, the thermal insulation layer 23 is filled in the inner side of the annular interlayer space, the multi-layer thermal insulation material aluminum foil + glass fiber is alternately overlapped, the thermal conductivity is less than or equal to 0.0008 W / (m·K), the environmental heat is blocked, the outer wall of the inner tube 22 is tightly wound with a copper spiral coil as a cooling medium flow channel 35, the cooling medium flow channel 35 is a spiral coil copper material, is tightly wound on the outer wall of the inner tube 22 and is located outside the thermal insulation layer 23, the effective heat exchange area is greater than or equal to 0.8 m², and sufficient contact with the inner tube 22 is ensured.

[0049] Further, when the liquid hydrogen is conveyed, the conveying pump 11 sucks the liquid hydrogen through the inlet pipe 13, pressurizes the liquid hydrogen through the impeller and sends the liquid hydrogen into the inner tube 22 from the outlet pipe 14, the thermal insulation layer 23 of the conveying assembly 200 is used as the first barrier to block more than 80% of the environmental heat, the residual heat is transmitted to the cooling medium flow channel 35 through the outer wall of the inner tube 22, and the refrigerator 31 drives the cooling medium helium to circulate in the closed loop, so that the heat is taken away and dissipated to the environment through the hot end of the refrigerator.

[0050] The control system monitors the temperature of the inner tube 22 in real time, when the temperature is higher than-252℃, the power of the refrigerator 31 is automatically increased by 200W at most to speed up the circulation of the cooling medium, when the temperature is lower than-255℃, the power is reduced to save energy, and if the leakage sensor 26 detects an abnormality, the safety interlock is triggered immediately, the liquid hydrogen supply is cut off and the machine is stopped.

[0051] The cooling assembly 300 comprises the cooling medium flow channel 35 and the refrigerator 31, the cold end of the refrigerator 31 is coupled with the cooling medium flow channel 35, and is used for providing low-temperature cooling medium to the cooling medium flow channel 35, the cooling medium flow channel 35 is arranged around the outer wall of the inner tube 22, the cooling medium flow channel 35 has a cooling medium inlet 33 and a cooling medium outlet 34, the cooling medium flow channel 35, the refrigerator 31 and the pipeline constitute a closed circulation loop, the refrigeration power of the refrigerator 31 is 80-200W, the minimum refrigeration temperature is-265℃, the cold end is coupled with the cooling medium flow channel 35 through the copper heat conduction block with a heat conduction coefficient greater than or equal to 380 W / (m·K), the cooling medium circulates in the loop, continuously takes away the heat around the inner tube 22, the closed circulation loop is filled with liquid nitrogen as the cooling medium, when the refrigerator 31 works, the cooling medium is cooled and naturally convectively circulates in the loop, continuously absorbs the heat from the outside when flowing through the spiral coil, so that the outer wall of the inner tube 22 is maintained at an extremely low temperature.

[0052] The annular interlayer space is embedded with a heat insulation layer 23 for actively removing the residual heat, the heat insulation layer 23 is one of high-vacuum multi-layer heat insulation material, vacuum powder heat insulation material or aerogel heat insulation material, the heat insulation layer 23 is attached to the inner wall of the outer pipe 21, and the inner wall of the heat insulation layer 23 is attached to the cooling medium flow channel 35.

[0053] The pumping assembly 100 comprises a delivery pump 11, which adopts a low-temperature centrifugal pump structure, the pump body is made of austenitic stainless steel, and the impeller is made of titanium alloy, the delivery pump 11 is adapted to a flow of 50-200 L / h, and the outlet pressure can reach 45 MPa, so as to ensure efficient pressurization of liquid hydrogen, one end of the delivery pump 11 is provided with a fixing seat 12, and the output end of the delivery pump 11 is provided with an impeller seat 16, the impeller seat 16 is integrally cast with the pump shell of the delivery pump 11, the internal flow channel is polished to have a roughness Ra≤0.8 μm, so as to reduce the flow resistance of liquid hydrogen, one end of the impeller seat 16 away from the delivery pump 11 is provided with a base 15, the base 15 is fixedly connected with the fixing seat 12 through a connecting piece, the base 15 is made of cast iron, and a shock-absorbing pad of nitrile rubber is arranged at the bottom of the base 15, so as to reduce the influence of pumping vibration on the pipeline;

[0054] The impeller seat 16 is provided with an inlet pipe 13 on one side and an outlet pipe 14 on the other side, the inlet pipe 13 is used for conveying liquid hydrogen into the inside of the impeller seat 16, and then outputting from the outlet pipe 14, the inlet pipe 13 is connected with a liquid hydrogen storage tank, and the outlet pipe 14 is communicated with the inner pipe 22 of the delivery assembly 200 through a flange, and a check valve is arranged on the pipeline.

[0055] The delivery assembly 200 further comprises a connecting seat 24 connected with the outlet pipe 14, and a bellows compensator is arranged in the connecting seat 24, which is used for absorbing the displacement caused by thermal expansion and cold contraction.

[0056] The refrigerator 31 is electrically connected with a power supply, and the refrigerator 31 is provided with connecting pipes 32 at both ends, one end of the connecting pipe 32 is connected with the refrigerator 31, and the other end is connected with a cooling medium inlet 33 and a cooling medium outlet 34, respectively.

[0057] The cooling medium flow channel 35 has a spiral coil structure, is tightly wound on the outer surface of the inner pipe 22, and the cooling medium flows in the inside of the cooling medium flow channel 35.

[0058] The cooling medium is one of liquid nitrogen, liquid helium or low-temperature refrigerant, which is used for increasing the heat exchange area and uniform cooling effect.

[0059] The outer pipe 21 is provided with a temperature sensor 25 at both ends of the outer wall, the temperature sensor 25 adopts an armored platinum resistance, is arranged in the axial direction of the inner pipe 22, has a measurement range of-270℃ to 50℃, and an accuracy of ±0.05℃, and the inner sides of the two temperature sensors 25 are provided with a leakage sensor 26, the leakage sensor 26 is arranged on the inner wall of the outer pipe 21, adopts a hydrogen-sensitive sensor, and is used for monitoring the liquid hydrogen leakage in real time.

[0060] Example two

[0061] The embodiment gives a specific structure of a small liquid hydrogen pump for hydrogen refueling station, as shown in the figure, including a pumping assembly 100, a conveying assembly 200 and a cooling assembly 300, the pumping assembly 100 is connected with the conveying assembly 200, and the cooling assembly 300 is connected with the conveying assembly 200. Figures 1-5

[0062] The conveying assembly 200 includes an inner tube 22 and an outer tube 21, the outer tube 21 is sleeved outside the inner tube 22 to form an annular interlayer space between the inner tube 22 and the outer tube 21, the inner tube 22 is used for conveying liquid hydrogen, and the outer tube 21 is used for protecting the inner tube 22, the inner tube 22 and the outer tube 21 are concentrically sleeved to form the annular interlayer space, a copper spiral coil pipe is tightly wound on the outer wall of the inner tube 22 as a cooling medium flow channel 35, the cooling medium flow channel 35 is a spiral coil purple copper material, is tightly wound on the outer wall of the inner tube 22, and the effective heat exchange area is greater than or equal to 0.8 m², so that the inner tube 22 is ensured to be fully contacted.

[0063] Further, when the liquid hydrogen is conveyed, the conveying pump 11 sucks in the liquid hydrogen through the inlet pipe 13, pressurizes the liquid hydrogen through the impeller, and sends the liquid hydrogen into the inner tube 22 from the outlet pipe 14, heat is transferred to the cooling medium flow channel 35 through the outer wall of the inner tube 22, and the refrigerator 31 drives the cooling medium helium to circulate in the closed loop, so that the heat is taken away and dissipated to the environment through the hot end of the refrigerator.

[0064] The control system monitors the temperature of the inner tube 22 in real time, when the temperature is higher than-252℃, the power of the refrigerator 31 is automatically increased by 200 W at most to speed up the circulation of the cooling medium, when the temperature is lower than-255℃, the power is reduced to save energy, and if the leakage sensor 26 detects an abnormality, the safety interlock is triggered immediately, the liquid hydrogen supply is cut off, and the machine is stopped.

[0065] The cooling assembly 300 includes the cooling medium flow channel 35 and the refrigerator 31, the cold end of the refrigerator 31 is coupled with the cooling medium flow channel 35, and is used for providing low-temperature cooling medium to the cooling medium flow channel 35, the cooling medium flow channel 35 is arranged around the outer wall of the inner tube 22, the cooling medium flow channel 35 has a cooling medium inlet 33 and a cooling medium outlet 34, the cooling medium flow channel 35, the refrigerator 31 and the pipeline constitute a closed circulation loop, the refrigeration power of the refrigerator 31 is 80-200 W, the minimum refrigeration temperature is-265℃, the cold end is coupled with the cooling medium flow channel 35 through a copper heat conduction block with a heat conduction coefficient greater than or equal to 380 W / (m·K), the cooling medium circulates in the loop, continuously takes away the heat around the inner tube 22, the closed circulation loop is filled with liquid nitrogen as the cooling medium, and when the refrigerator 31 works, the cooling medium is cooled and naturally convectively circulates in the loop, continuously absorbs the heat from the outside when flowing through the spiral coil pipe, so that the outer wall of the inner tube 22 is maintained at an extremely low temperature.

[0066] ​The pumping assembly 100 comprises a delivery pump 11, which adopts a low-temperature centrifugal pump structure, the pump body is made of austenitic stainless steel, the impeller is made of titanium alloy, the adaptive flow is 50-200 L / h, the outlet pressure can reach 45 MPa, the liquid hydrogen can be efficiently pressurized, one end of the delivery pump 11 is provided with a fixing seat 12, the output end of the delivery pump 11 is provided with an impeller seat 16, the impeller seat 16 is integrally cast with the pump shell of the delivery pump 11, the internal flow channel is polished to have a roughness Ra≤0.8 μm, the liquid hydrogen flow resistance is reduced, the end of the impeller seat 16 away from the delivery pump 11 is provided with a base 15, the base 15 is fixedly connected with the fixing seat 12 through a connecting piece, the base 15 is made of cast iron, a shock pad butyronitrile rubber is arranged at the bottom to reduce the influence of pumping vibration on the pipeline.

[0067] The impeller seat 16 is provided with an inlet pipe 13 on one side and an outlet pipe 14 on the other side, the inlet pipe 13 is used for conveying the liquid hydrogen into the inside of the impeller seat 16 and then output from the outlet pipe 14, the inlet pipe 13 is connected with a liquid hydrogen storage tank, the outlet pipe 14 is communicated with the inner pipe 22 of the delivery assembly 200 through a flange, and a check valve is arranged on the pipeline.

[0068] The delivery assembly 200 further comprises a connecting seat 24 connected with the outlet pipe 14, the connecting seat 24 is internally provided with a corrugated pipe compensator for absorbing the displacement generated by thermal expansion and cold contraction.

[0069] The refrigerator 31 is electrically connected with a power supply, the refrigerator 31 is provided with connecting pipes 32 at both ends, one end of the connecting pipe 32 is connected with the refrigerator 31, and the other end is respectively connected with a cooling medium inlet 33 and a cooling medium outlet 34.

[0070] The cooling medium flow channel 35 is in a spiral coil pipe structure and is tightly wound on the outer surface of the inner pipe 22, and a cooling medium flows in the inside;

[0071] The cooling medium is one of liquid nitrogen, liquid helium or low-temperature refrigerant, which is used for increasing the heat exchange area and uniform cooling effect.

[0072] The outer wall of the outer pipe 21 is provided with a temperature sensor 25 at both ends, the temperature sensor 25 adopts an armored platinum resistance, is arranged axially along the inner pipe 22, has a measurement range of-270℃ to 50℃ and an accuracy of ±0.05℃, the inner sides of the two temperature sensors 25 are provided with leakage sensors 26, the leakage sensors 26 are arranged on the inner wall of the outer pipe 21 and adopt hydrogen-sensitive sensors to monitor the liquid hydrogen leakage in real time, the inner wall of the outer pipe 21 is further provided with a radiation-proof screen 27 made of aluminum foil, the radiation-proof screen 27 is connected with the cold end of the refrigerator 31 through a flexible heat-conducting cable, so that the temperature of the radiation-proof screen 27 is also maintained at a low temperature level, the radiation-proof screen 27 effectively blocks the radiation heat transfer, and the radiation-proof screen 27 is connected with the cold end of the refrigerator 31, so that the temperature is maintained at a low temperature level, which is used for effectively blocking the radiation heat flow.

[0073] Working principle:

[0074] When transporting liquid hydrogen, the delivery pump 11 sucks in liquid hydrogen through the inlet pipe 13, pressurizes it through the impeller, and sends it into the inner tube 22 from the outlet pipe 14. The adiabatic layer 23 of the delivery assembly 200 serves as the first barrier, and the liquid hydrogen flows in the inner tube 22. The ambient heat is first blocked by the passive adiabatic layer 23, and the residual heat is absorbed by the cold screen of the active cooling structure, and is discharged outside the system by the refrigerator 31, thereby ensuring the stable delivery of liquid hydrogen and blocking more than 80% of the ambient heat. The residual heat is transferred to the cooling medium flow channel 35 through the outer wall of the inner tube 22, and the refrigerator 31 drives the cooling medium helium to circulate in a closed loop, taking away the heat and dissipating it to the environment through the hot end of the refrigerator.

[0075] The control system monitors the temperature of the inner tube 22 in real time. When the temperature is higher than -252℃, the power of the refrigerator 31 is automatically increased by 200W to speed up the circulation of the cooling medium. When the temperature is lower than -255℃, the power is reduced to save energy. If the leakage sensor 26 detects an anomaly, the safety interlock is triggered immediately to shut off the liquid hydrogen supply and stop the machine

[0076] The control system includes a temperature sensor 25 arranged in the annular interlayer space, a leakage sensor 26 arranged on the inner tube 22, and a controller. When the temperature sensor 25 detects an upward trend, the controller automatically increases the power level of the refrigerator 31 to enhance the cooling effect. When the heat load is low, the power is reduced to save energy.

[0077] The cold end of the refrigerator 31 is coupled to the cooling medium flow channel 35 to provide low-temperature cooling medium to the cooling medium flow channel 35. The cooling medium flow channel 35 is arranged around the outer wall of the inner tube 22. The cooling medium flow channel 35 has a cooling medium inlet 33 and a cooling medium outlet 34. The cooling medium flow channel 35, the refrigerator 31, and the pipeline form a closed circulation loop. The refrigerator 31 has a refrigeration power of 80-200W and a minimum refrigeration temperature of -265℃. The cold end is coupled to the cooling medium flow channel 35 through a copper heat conduction block with a heat conduction coefficient ≥380W / (m·K). The cooling medium circulates in the loop, continuously taking away the heat around the inner tube 22. The closed circulation loop is filled with liquid nitrogen as the cooling medium. When the refrigerator 31 is working, the cooling medium is cooled and naturally convects in the loop, continuously absorbing heat from the outside when flowing through the spiral coil, so that the outer wall of the inner tube 22 is maintained at a very low temperature.

[0078] It should be noted that the above-mentioned embodiments are merely used to clearly illustrate the technical solutions of the present application, and should not be construed as limitations to the present application. Based on the above-mentioned embodiments, those skilled in the art can make other variations or modifications without departing from the spirit of the present application. The present application is not required to enumerate all of the embodiments, and the variations or modifications made without departing from the spirit of the present application should fall within the scope of the present application.

Claims

1. A small-sized liquid hydrogen pump for a hydrogen refueling station, characterized by, The application relates to a hydrogen delivery device, which comprises a pumping assembly (100), a conveying assembly (200) and a cooling assembly (300), wherein the pumping assembly (100) is connected with the conveying assembly (200), and the cooling assembly (300) is connected with the conveying assembly (200). The conveying assembly (200) comprises an inner tube (22) and an outer tube (21), the outer tube (21) is sleeved outside the inner tube (22), and an annular interlayer space is formed between the inner tube (22) and the outer tube (21), the inner tube (22) is used for conveying liquid hydrogen, and the outer tube (21) is used for protecting the inner tube (22). The cooling assembly (300) comprises a cooling medium flow channel (35) and a refrigerator (31), the cooling medium flow channel (35) is arranged on the outer wall of the inner tube (22), the cooling medium flow channel (35) is provided with a cooling medium inlet (33) and a cooling medium outlet (34), the cooling medium flow channel (35), the refrigerator (31) and a pipeline constitute a closed circulation loop, and cooling medium circulates in the loop to continuously take away heat around the inner tube (22).

2. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 1, characterized by The annular interlayer space is embedded with an adiabatic layer (23) for actively removing residual heat, the adiabatic layer (23) is attached to the inner wall of the outer tube (21), and the inner wall of the adiabatic layer (23) is attached to the cooling medium flow channel (35).

3. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 1, characterized by The pumping assembly (100) comprises a conveying pump (11), one end of the conveying pump (11) is provided with a fixing seat (12), and the output end of the conveying pump (11) is provided with an impeller seat (16). One side of the impeller seat (16) is provided with an inlet pipe (13), and the other side is provided with an outlet pipe (14).

4. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 3, characterized by The conveying assembly (200) further comprises a connecting seat (24) connected with the outlet pipe (14), the connecting seat (24) is internally provided with a corrugated pipe compensator for absorbing displacement caused by thermal expansion and cold contraction.

5. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 1, characterized by Temperature sensors (25) are arranged at the two ends of the outer tube (21), and leakage sensors (26) are arranged on the inner sides of the two temperature sensors (25).

6. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 1, wherein The refrigerator (31) is electrically connected with a power supply, connecting pipes (32) are arranged at the two ends of the refrigerator (31), one end of each connecting pipe (32) is connected with the refrigerator (31), and the other end of each connecting pipe (32) is connected with the cooling medium inlet (33) and the cooling medium outlet (34) respectively.

7. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 1, characterized by The cooling medium flow channel (35) is in a spiral coil structure and is tightly wound on the outer surface of the inner tube (22), and cooling medium flows in the cooling medium flow channel (35); The cooling medium is one of liquid nitrogen, liquid helium and low-temperature refrigerant, and is used for increasing a heat exchange area and uniform cooling effect.

8. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 1, characterized by An anti-radiation screen (27) is further arranged on the inner wall of the outer tube (21), the anti-radiation screen (27) is connected with the cold end of the refrigerator (31), so that the temperature of the anti-radiation screen (27) is maintained at a low temperature level, and the anti-radiation screen (27) is used for effectively blocking radiation heat flow.

9. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 2, wherein The adiabatic layer (23) is one of high-vacuum multi-layer adiabatic material, vacuum powder adiabatic material and aerogel adiabatic material.

10. A small-sized liquid hydrogen pump for a hydrogen refueling station according to claim 3, wherein The impeller seat (16) is provided with a base (15) away from one end of the delivery pump (11), and the base (15) is fixedly connected with the fixing seat (12) through a connecting piece.

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