CN113113643B

CN113113643B - Hydrogen closed circulation system for fuel cell

Info

Publication number: CN113113643B
Application number: CN202110267697.9A
Authority: CN
Inventors: 任杰; 杨志祎; 郭亚卿; 鲍连福; 刘晓凯
Original assignee: Jiayu Hydrogen Energy Technology Liaoning Co ltd
Current assignee: Jiayu Hydrogen Energy Technology Liaoning Co ltd
Priority date: 2021-03-12
Filing date: 2021-03-12
Publication date: 2022-06-14
Anticipated expiration: 2041-03-12
Also published as: CN113113643A

Abstract

The application relates to a hydrogen closed circulation system for a fuel cell, which comprises an ejector, wherein the ejector comprises a main pipeline and a side pipeline, one end of the side pipeline is communicated with the main pipeline, ejector connectors are respectively installed at two ends of the main pipeline, the ejector connectors are divided into an air inlet connector and an air outlet connector, a flow guide device is arranged on the main pipeline, the flow guide devices are respectively arranged at two sides of the side pipeline and comprise a limiting cylinder and a sealing cylinder, the limiting cylinder is fixedly arranged on the side wall of the main pipeline, and the sealing cylinder is slidably arranged in the limiting cylinder; the injection joint comprises an injection pipe fixedly installed in the main pipeline, and the injection pipe is arranged in the sealing cylinder in a penetrating mode and is tightly attached to the inner side wall of the sealing cylinder. This application has if the inlet connection or the junction of giving vent to anger the joint not inseparable, also is difficult for appearing the effect of gas leakage's phenomenon.

Description

Hydrogen closed circulation system for fuel cell

Technical Field

The application relates to the field of injection backflow equipment, in particular to a hydrogen closed circulation system for a fuel cell.

Background

In proton exchange membrane fuel cells, maintaining proton exchange membrane water balance is important to the life of the stack. On one hand, the dry film phenomenon can be generated due to the low water content, and the transmission of protons is obstructed; on the other hand, the water flooding phenomenon can be generated when the water content is too high, so that the gas diffusion in the porous medium is hindered, and the output voltage of the electric pile is reduced. In addition, the continuous accumulation of impurity gases that penetrate from the cathode side to the anode can also affect the performance of the stack. In order to solve the above problems of water blockage and gas permeation, a hydrogen discharge method is generally used to discharge water and accumulated impurity gases generated inside the stack. The hydrogen discharge frequency is too low, so that water blockage and impurity gas accumulation are easily caused, and the performance of the pile is reduced; too high a hydrogen discharge frequency wastes hydrogen and presents a potential hazard. In order to ensure the normal and stable operation of the fuel cell and discharge the water generated in the fuel cell to the outside of the cell, a hydrogen circulation method is generally adopted, the water generated in the cell is taken out of the cell, a water separation device is used for separating out the liquid water, and the hydrogen is circulated back to the cell for reuse, so that the hydrogen utilization rate is improved. At present, in a hydrogen closed circulation system, an important part is a hydrogen return injection device.

The use of hydrogen gas circulation is effective in improving hydrogen circulation, but requires the consumption of electric power to maintain its operation, and contains many mechanical parts accompanied by vibration and noise, and bearings, lubricating oil, and the like. Chinese patent No. CN210576236U discloses an injection backflow device for hydrogen circulation of fuel cell, which comprises an injector, an air inlet joint, an air outlet joint and a backflow joint, wherein the injector is hollow and has openings at the left and right ends, the right end of the air inlet joint and the left end of the air outlet joint horizontally extend into the openings at the left and right ends of the injector respectively, so as to form a closed mixing chamber between the injector, the air inlet joint and the air outlet joint are respectively provided with an air inlet channel and an air outlet channel horizontally penetrating through the air inlet joint and the air outlet joint, the right end of the air inlet channel and the left end of the air outlet channel are respectively communicated with the mixing chamber, the middle part of the upper end of the injector is provided with a connecting port communicated with the mixing chamber, the backflow joint is vertically arranged, and the lower end of the backflow joint extends into the connecting port and is communicated with the mixing chamber. It has the advantages of simple structure, reliable operation, no pollution and the like.

In view of the above-mentioned related art, the inventor thinks that when the structure is installed, the air inlet joint and the air outlet joint are inserted and fixed in the ejector, and when the structure is used, the connection between the air inlet joint and the air outlet joint is unstable due to the insufficient firmness of the structure, thereby easily causing the problem of gas leakage.

Disclosure of Invention

In order to improve the problem that gas leakage is easy to occur, the application provides a hydrogen closed circulation system for a fuel cell.

The hydrogen closed circulation system for the fuel cell adopts the following technical scheme:

the hydrogen closed circulation system for the fuel cell comprises an ejector, wherein the ejector comprises a main pipeline and a side pipeline, one end of the side pipeline is communicated with the main pipeline, ejector connectors are installed at two ends of the main pipeline and are divided into an air inlet connector and an air outlet connector, a flow guide device is arranged on the main pipeline and is arranged on each of two sides of the side pipeline, the flow guide devices comprise a limiting cylinder and a sealing cylinder, the limiting cylinders are fixedly arranged on the side wall of the main pipeline, one ends, close to each other, of the two limiting cylinders are limiting near ends, the inner diameter of the limiting near ends is smaller than that of the other ends of the limiting cylinders, the sealing cylinders are slidably arranged in the limiting cylinders, one ends, adjacent to the limiting near ends, of the sealing cylinders are sealing near ends, the outer diameter of the sealing near ends is not larger than that of the limiting near ends, and the outer diameter of the other ends of the sealing cylinders is not smaller than that of the limiting near ends; the injection joint comprises an injection pipe fixedly installed in the main pipeline, and the injection pipe is arranged in the sealing cylinder in a penetrating mode and is tightly attached to the inner side wall of the sealing cylinder.

Through adopting above-mentioned technical scheme, spacing section of thick bamboo is fixed to be set up on the lateral wall of trunk line, and inside formation is close to the structure that pipeline just is more narrow more near. A sealing barrel slidable mounting is in a spacing section of thick bamboo, when moving towards the side pipeline, can laminate with the inside wall of a spacing section of thick bamboo to reach sealed effect. The injection pipe in the injection joint penetrates through the sealing barrel, and the injection pipe is fixedly arranged in the main pipeline, so that the position of the sealing barrel sleeved on the injection pipe is kept fixed. When gas is introduced, the gas is introduced from the injection pipe at the gas inlet joint and flows to the cavity between the two injection joints in the main pipe. Because the gas that gets into is the hydrogen of high pressure low velocity of flow when letting in gas, when gas passes through the injection pipe of air inlet joint, the continuous decompression acceleration rate of gas to reach high speed when will flowing to the cavity between two injection joints. Under the drive of the gas, other gas in the cavity continuously flows forwards, so that the gas in the cavity becomes rare, and the pressure is reduced. If the connection part of the air inlet joint or the air outlet joint is not tight and the phenomenon of air leakage exists, the air pressure of one side, away from the cavity between the two injection joints, of the sealing cylinder is the same as the atmospheric pressure and is greater than the air pressure of the cavity between the two injection joints, so that the sealing cylinder is pushed to move towards the cavity between the two injection joints. The higher the speed of gas in the cavity between the two injection joints, the tighter the sealing barrel is pushed, and the phenomenon of gas leakage is not easy to occur.

Optionally, trunk line end department is provided with fixing device, and fixing device includes the solid fixed cylinder, and the both ends of solid fixed cylinder lateral wall, the end of trunk line and draw and penetrate the equal fixed flange ring that sets up of one end that sealed near-end was kept away from to the pipe, gu fixed cylinder one end and trunk line end flange joint draw penetrate to penetrate the pipe and wear to establish in the solid fixed cylinder, and draw and penetrate the pipe and keep away from the one end flange joint of trunk line with the solid fixed cylinder.

Through adopting above-mentioned technical scheme, the fixed cylinder passes through the flange mounting in the end department of trunk line, and flange joint's structure has increased the leakproofness of trunk line. The injection pipe is arranged in the fixed cylinder in a penetrating mode and is connected through the flange, the sealing performance is improved, and meanwhile the injection pipe is stably fixed. Because need set up spacing section of thick bamboo and a sealed section of thick bamboo in the trunk line, consequently the diameter of trunk line can be greater than and draw the ejector pipe. And through setting up the fixed cylinder, can make the diameter of fixed cylinder slightly be greater than and draw and penetrate the pipe to make the fixed cylinder can link up drawing the pipe, make draw and penetrate the difficult phenomenon that the damage appears of pipe.

Optionally, the injection pipe is divided into a straight pipe section and an inclined pipe section, the straight pipe section is cylindrical in shape and penetrates through the inner side of the fixed cylinder, the outer diameter of one end, connected with the straight pipe section, of the inclined pipe section is smaller than the outer diameter of one end, far away from the straight pipe section, of the inclined pipe section, the sealing cylinder penetrates through the inclined pipe section, and the outer diameter of one end, far away from the straight pipe section, of the inclined pipe section is larger than the inner diameter of the sealing near end.

Through adopting above-mentioned technical scheme, the sealing barrel cover is established on the pipe chute section, and the sealing barrel is being promoted when moving towards two cavity departments of drawing between the injection joint, and is pressing from both sides with the pipe chute section cooperation simultaneously, further improvement the sealed effect of a sealing barrel, be difficult to the phenomenon that gas leakage appears.

Optionally, a guiding device is arranged on the ejector and comprises a guiding barrel and a guiding ring, the guiding barrel is fixedly arranged on the ejecting pipe of the air outlet joint and is positioned at one end, close to the air inlet joint, of the ejecting pipe, the outer diameters of the ends, connected with each other, of the guiding barrel and the ejecting pipe are the same, and the outer diameter of one end, connected with the ejecting pipe, of the guiding barrel is larger than the outer diameter of one end, far away from the ejecting pipe, of the guiding barrel; the guide ring is fixedly arranged on the sealing barrel of the air inlet joint and located at the sealing near end of the sealing barrel, the inner diameter of one end, connected with the sealing barrel, of the guide ring is the same, and the inner diameter of one end, connected with the sealing barrel, of the guide ring is smaller than the inner diameter of one end, far away from the sealing barrel, of the guide ring.

Through adopting above-mentioned technical scheme, the setting up of guide cylinder and guide ring makes two draw and penetrates the cavity formation between the joint similar to the structure of bowl form, when gas blows in two from the side pipeline and draws the cavity between the joint, under guide cylinder and guide ring's guide and the gas-in connection spun gas guide, in the easier blowing in joint of giving vent to anger, the phenomenon of the sealed section of thick bamboo of difficult appearing blowing in reverse direction makes sealed section of thick bamboo can have good protection effect.

Optionally, the length of a sealed section of thick bamboo is less than the length of a spacing section of thick bamboo, and the internal diameter of a solid fixed cylinder is less than the internal diameter of trunk line, and compression spring is installed to the one end that sealed near-end was kept away from to a sealed section of thick bamboo, and compression spring establishes on drawing the injection pipe, and compression spring and solid fixed cylinder are close to the terminal surface butt of trunk line.

Through adopting above-mentioned technical scheme, the length setting of a sealed section of thick bamboo is shorter to can install compression spring, under compression spring's promotion, can just begin to blow in gas to two cavitys between the injection joint, make a sealed section of thick bamboo still be located the position department adjacent with the cavity. The gap between the upper limiting cylinder and the injection pipe is filled in time after the subsequent gas leakage phenomenon occurs.

Optionally, the cavity inside the injection pipe is an injection passage, the injection passage includes a tapered passage and a reduction passage, the tapered passage is located at one end of the injection pipe far away from another injection joint, the diameters of the two ends of the tapered passage are different, the end of the tapered passage adjacent to the reduction passage is the end with a small diameter, the diameter of the reduction passage is smaller than that of the tapered passage, and the diameter of the reduction passage on the air inlet joint is smaller than that of the reduction passage on the air outlet joint.

By adopting the technical scheme, the closer to the cavity between the two injection joints, the smaller the diameter of the conical passage in the injection passage is until the diameter of the reduced passage is smaller than that of the conical passage. The velocity of the gas is further increased as it passes through the inlet fitting, thereby achieving an ultra high velocity as it passes through the inlet fitting. And because the diameter of the narrowing channel on the air inlet joint is smaller than that on the air outlet joint. Gas can be blown into the reduced passage of the gas outlet joint more easily. When the air outlet connector is used, the cross section of the injection channel is increased, so that the air pressure is reduced, the speed is reduced, and the subsequent conveying is facilitated.

Optionally, an extension pipe is integrally formed at one end of the injection pipe, which is far away from the other injection joint.

Through adopting above-mentioned technical scheme, draw and penetrate the extension pipe on the pipe and when setting up integrated into one piece on drawing penetrating the pipe, the flange ring cover is established and is welded on it. The partial pipeline on one side of the flange ring close to the ejector is the ejector pipe, and the partial pipeline on the other side is the lengthening pipe. The injection pipe and the extension pipe are integrally formed, so that the connecting part is reduced. The whole structure is more compact, and cracks are not easy to appear.

Optionally, an included angle between the axis of the side pipeline and the axis of the main pipeline is an acute angle, and the side pipeline inclines towards one side of the air outlet joint.

Through adopting above-mentioned technical scheme, with the slope of side pipeline setting, make through side pipeline gas blow to guide ring department after, under the guide of the gas through admission joint, more easy insufflate in the injection pipe of giving vent to anger joint.

In summary, the present application includes at least one of the following beneficial technical effects:

1. if the connection part of the air inlet joint or the air outlet joint is not tight, the phenomenon of gas leakage is not easy to occur;

2. the whole structure is more compact and is not easy to crack.

Drawings

Fig. 1 is a schematic structural diagram of the present embodiment.

Fig. 2 is a schematic sectional view of the present embodiment.

Fig. 3 is a schematic view of the structure of the guide device.

Description of reference numerals: 1. an ejector; 11. a main pipeline; 12. a side duct; 13. a return joint; 2. an injection joint; 21. an air inlet joint; 22. an air outlet joint; 23. an injection pipe; 231. a straight pipe section; 232. an oblique pipe section; 24. lengthening a pipe; 3. a fixing device; 31. a fixed cylinder; 4. a flow guide device; 41. a limiting cylinder; 42. a sealing cylinder; 43. a compression spring; 5. a guide device; 51. a guide cylinder; 52. a guide ring; 6. an injection passage; 61. reducing the channel; 62. a tapered channel; 63. a straight channel.

Detailed Description

The present application is described in further detail below with reference to figures 1-3.

The embodiment of the application discloses a hydrogen closed circulation system for a fuel cell. Referring to fig. 1 and 2, the ejector 1 includes a main pipe 11 and a side pipe 12. Injection joints 2 are fixedly installed at two ends of the main pipeline 11, wherein one injection joint 2 is an air inlet joint 21, and the other injection joint is an air outlet joint 22. One end of the side pipe 12 is communicated with the main pipe 11 and connected to the middle part of the main pipe 11, and the side pipe 12 is inclined toward the side close to the air outlet joint 22. A return joint 13 is also mounted on the side pipe 12. The main pipe 11 is provided with a fixing device 3, a flow guiding device 4 and a guiding device 5.

Referring to fig. 2, the injection joint 2 includes an injection pipe 23, and the injection pipe 23 is divided into two sections, namely a straight pipe section 231 and an inclined pipe section 232. The straight pipe section 231 is cylindrical in shape, and the inclined pipe section 232 is circular truncated cone in shape. The end of the diagonal pipe section 232 connected to the straight pipe section 231 is the smallest end, and the outer diameter of the end is the same as the outer diameter of the straight pipe section 231. An extension pipe 24 is integrally formed on the end surface of the straight pipe section 231 away from the inclined pipe section 232, and the shape of the extension pipe 24 is the same as that of the straight pipe section 231.

Referring to fig. 2, the fixing device 3 includes a fixing cylinder 31, and the inner diameter of the fixing cylinder 31 is slightly larger than the outer diameter of the straight pipe section 231. And flange rings are fixedly arranged at two ends of the outer side surface of the fixed cylinder 31, and one end of the fixed cylinder 31 is connected with the end flange of the main pipeline 11. The straight pipe section 231 of the injection pipe 23 is inserted into the fixed cylinder 31, and the extension pipe 24 is located on the side of the fixed cylinder 31 far away from the main pipe 11. A flange ring is sleeved and welded at one end of the lengthening pipe 24 adjacent to the injection pipe 23, and the flange ring is fixedly connected with a flange ring at the other end of the fixed cylinder 31.

Referring to fig. 2 and 3, the deflector 4 is provided one on each side of the side duct 12. The flow guiding device 4 comprises a limiting cylinder 41 and a sealing cylinder 42, wherein the limiting cylinder 41 is integrally formed on the inner side wall of the main pipe 11. The end of the two limiting cylinders 41 close to each other is a limiting proximal end, a gap is formed between the limiting proximal end of the air inlet joint 21 and the side pipeline 12, and the limiting proximal end of the air outlet joint 22 is adjacent to the side pipeline 12. The inner diameter at the proximal end of the stopper is smaller than the inner diameter at the other end of the stopper cylinder 41. The sealing cylinder 42 is arranged in the limiting cylinder 41 in a penetrating mode and sleeved on the inclined tube section 232 of the injection tube 23, and the length of the sealing cylinder 42 is smaller than that of the limiting cylinder 41. The end of the two sealing barrels 42 adjacent to each other is a sealed proximal end. The sealing cylinder 42 has a circular truncated cone shape, and the proximal end of the seal is the smallest end of the sealing cylinder 42. The outer diameter at the proximal end of the seal is slightly less than the inner diameter at the proximal end of the stop and the outer diameter at the other end of the seal cartridge 42 is greater than the inner diameter at the proximal end of the stop. The inner diameter at the proximal end of the seal is slightly smaller than the outer diameter of the end of the angled tube section 232 distal from the straight tube section 231. Namely, when the sealed near end is adjacent to the position of the limit near end, the outer side surface of the sealing cylinder 42 is tightly attached to the inner side wall of the limit cylinder 41, and the inner side wall of the sealing cylinder 42 is tightly attached to the inclined tube section 232 of the injection tube 23.

Referring to fig. 2, a compression spring 43 is installed at one end of the sealing cylinder 42 away from the sealing proximal end, and the compression spring 43 is sleeved on the injection pipe 23 and is located inside the limiting cylinder 41. The other end of the compression spring 43 abuts against an end surface of the fixed cylinder 31 close to the main pipe 11. The sum of the natural length of the compression spring 43 and the length of the sealing barrel 42 is greater than the distance between the stationary barrel 31 and the adjacent proximal end of the stopper. The sealing cylinder 42 can be kept at a position adjacent to the cavity immediately after the gas starts to be blown into the cavity between the two injection joints 2 by the urging of the compression spring 43. The gap between the upper limiting cylinder 41 and the injection pipe 23 can be filled in time after the subsequent gas leakage phenomenon occurs.

Referring to fig. 2 and 3, the guiding device 5 includes a guiding cylinder 51 and a guiding ring 52, and the guiding cylinder 51 is integrally formed on the injecting pipe 23 of the air outlet joint 22 and is located at an end surface of the injecting pipe 23 close to the air inlet joint 21. The guide cylinder 51 is in a circular truncated cone shape, one end of the guide cylinder 51 connected with the injection pipe 23 is the largest end, and the outer diameter of the largest end of the guide cylinder 51 is the same as that of one end of the inclined pipe section 232 close to the guide cylinder 51. The guide ring 52 is integrally formed on the sealing cylinder 42 of the air inlet joint 21 and located at the sealing proximal end of the sealing cylinder 42, and the guide ring 52 is also fixedly connected with the inner side wall of the main pipe 11. The guide ring 52 is connected to the sealing cylinder 42 with an inner diameter at one end equal to the inner diameter at the proximal end of the seal, and the inner diameter of the end of the guide ring 52 remote from the sealing cylinder 42 is greater than the inner diameter at the proximal end of the seal. The arrangement of the guide cylinder 51 and the guide ring 52 enables the cavity between the two injection joints 2 to form a structure similar to a bowl shape, when gas is blown into the cavity between the two injection joints 2 from the side pipeline 12, under the guide of the guide cylinder 51 and the guide ring 52 and the guide of the gas sprayed by the gas inlet joint 21, the gas is more easily blown into the gas outlet joint 22, the phenomenon that the sealing cylinder 42 is blown reversely is not easy to occur, and the sealing cylinder 42 can have a good protection effect.

Referring to fig. 1 and 2, the cavity inside the injection pipe 23 is an injection passage 6, and the injection passage 6 is divided into a reduced passage 61, a tapered passage 62 and a straight passage 63. The reduced passage 61 is located adjacent to the side pipe 12, the tapered passage 62 is located on a side of the reduced passage 61 remote from the side pipe 12, and the straight passage 63 is located on a side of the tapered passage 62 remote from the side pipe 12. The diameter of the straight channel 63 is the same as the inner diameter of the elongated tube 24. The diameters of the two ends of the tapered channel 62 are different, and the end of the tapered channel 62 adjacent to the reduced channel 61 is the end with the smaller diameter. The diameter of the reduced passage 61 is smaller than that of the end of the tapered passage 62, and the diameter of the reduced passage 61 on the outlet connector 22 is larger than that of the reduced passage 61 on the inlet connector 21. The velocity of the gas is further increased as it passes through the inlet fitting 21, thereby achieving a super high velocity as it passes through the inlet fitting 21. And because the diameter of the reduced passage 61 of the outlet connector 22 is larger than the diameter of the reduced passage 61 of the inlet connector 21, gas can be blown into the reduced passage 61 of the outlet connector 22 more easily. When the gas passes through the gas outlet joint 22, the cross section of the injection channel 6 is increased, so that the gas pressure is reduced, the speed is reduced, and the subsequent gas delivery is facilitated.

The implementation principle of the hydrogen closed circulation system for the fuel cell in the embodiment of the application is as follows: during installation, the sealing cylinder 42 is sleeved on the straight pipe section 231, and the compression spring 43 is installed on the end surface of the sealing cylinder 42. Then, the extension pipe 24 is inserted through the fixing cylinder 31, and a flange is sleeved and welded at one end of the extension pipe 24 close to the straight pipe section 231, and is fixed on the fixing cylinder 31. The fixed barrel 31 is then mounted on the main pipe 11. Under the urging of the compression spring 43, the sealing barrel 42 moves to a position adjacent to the proximal end of the stopper and engages the stopper barrel 41 and the beveled tube section 232.

When gas leakage occurs, the leakage occurs mostly at the position where the pipeline is connected, i.e. at the position where the flange is connected. When gas is introduced, the gas is introduced from the injection pipe 23 at the air inlet joint 21 and flows into the cavity between the two injection joints 2 in the main pipe 11. Because the gas is high-pressure low-flow-rate hydrogen when the gas is introduced, when the gas passes through the injection passage 6 of the injection pipe 23 of the air inlet joint 21, the gas is continuously decompressed and accelerated, and reaches high speed when the gas is about to flow into the cavity between the two injection joints 2. Under the drive of the gas, other gas in the cavity continuously flows forwards, so that the gas in the cavity becomes rare, and the pressure is reduced. At this time, if the connection part of the air inlet joint 21 or the air outlet joint 22 is not tight, and the phenomenon of air leakage exists, the air pressure of one side of the sealing cylinder 42, which is far away from the cavity between the two injection joints 2, is the same as the atmospheric pressure and is greater than the air pressure of the cavity between the two injection joints 2, so that the sealing cylinder 42 is pushed to move towards the cavity between the two injection joints 2. When the sealing cylinder 42 is pushed to move towards the cavity between the two injection joints 2, the sealing cylinder 42 is matched and clamped with the limiting cylinder 41 and the inclined pipe section 232, so that the sealing cylinder 42 has a sealing effect, and the phenomenon of gas leakage is not easy to occur. And the higher the speed of the gas to flow into the cavity between the two injection joints 2, the tighter the sealing cylinder 42 is pushed, and the phenomenon of gas leakage is less likely to occur.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a hydrogen closed circulation system for fuel cell, includes ejector (1), ejector (1) including trunk line (11) and side pipeline (12), the one end and trunk line (11) intercommunication of side pipeline (12), trunk line (11) both ends are all installed and are drawn and penetrate joint (2), draw and penetrate joint (2) and divide into air-inlet joint (21) and air-outlet joint (22), its characterized in that: the main pipeline (11) is provided with a flow guide device (4), two sides of the side pipeline (12) of the flow guide device (4) are respectively provided with one flow guide device, each flow guide device (4) comprises a limiting cylinder (41) and a sealing cylinder (42), the limiting cylinders (41) are fixedly arranged on the side wall of the main pipeline (11), one ends, close to each other, of the two limiting cylinders (41) are limiting near ends, the inner diameter of each limiting near end is smaller than that of the other end of each limiting cylinder (41), the sealing cylinders (42) are slidably arranged in the limiting cylinders (41), one ends, adjacent to the limiting near ends, of the sealing cylinders (42) are sealing near ends, the outer diameters of the sealing near ends are not larger than that of the limiting near ends, and the outer diameters of the other ends of the sealing cylinders (42) are not smaller than that of the limiting near ends; the injection joint (2) comprises an injection pipe (23) fixedly arranged in the main pipeline (11), and the injection pipe (23) is arranged in the sealing cylinder (42) in a penetrating way and is tightly attached to the inner side wall of the sealing cylinder (42); trunk line (11) end department is provided with fixing device (3), and fixing device (3) are including solid fixed cylinder (31), and the both ends of solid fixed cylinder (31) lateral wall, the end of trunk line (11) and draw and penetrate the equal fixed flange ring that sets up of one end that sealed near-end was kept away from in pipe (23), solid fixed cylinder (31) one end and trunk line (11) end flange joint, draw and penetrate pipe (23) and wear to establish in solid fixed cylinder (31), and draw and penetrate pipe (23) and solid fixed cylinder (31) and keep away from the one end flange joint of trunk line (11).

2. A hydrogen gas closed circulation system for a fuel cell according to claim 1, characterized in that: draw and penetrate pipe (23) and divide into straight tube section (231) and pipe chute section (232), the appearance of straight tube section (231) is cylindrical and wears to establish at solid fixed cylinder (31) inboard, the external diameter that pipe chute section (232) and straight tube section (231) are connected one end is less than the external diameter of keeping away from straight tube section (231) one end, sealing cylinder (42) are worn to establish in pipe chute section (232), and pipe chute section (232) keep away from the one end external diameter of straight tube section (231) and be greater than the internal diameter of sealed near-end.

3. A hydrogen gas closed circulation system for a fuel cell according to claim 2, characterized in that: the ejector (1) is provided with a guide device (5), the guide device (5) comprises a guide cylinder (51) and a guide ring (52), the guide cylinder (51) is fixedly arranged on an ejector pipe (23) of the air outlet connector (22) and is positioned at one end, close to the air inlet connector (21), of the ejector pipe (23), the outer diameters of the mutually connected ends of the guide cylinder (51) and the ejector pipe (23) are the same, and the outer diameter of one end, connected with the ejector pipe (23), of the guide cylinder (51) is larger than that of one end, far away from the ejector pipe (23), of the guide cylinder (51); the guide ring (52) is fixedly arranged on the sealing cylinder (42) of the air inlet joint (21) and is located at the sealing proximal end of the sealing cylinder (42), the inner diameter of one end, connected with the sealing cylinder (42), of the guide ring (52) is the same, and the inner diameter of one end, connected with the sealing cylinder (42), of the guide ring (52) is smaller than that of one end, far away from the sealing cylinder (42), of the guide ring (52).

4. A hydrogen gas closed circulation system for a fuel cell according to claim 3, characterized in that: the length of a sealed section of thick bamboo (42) is less than the length of a spacing section of thick bamboo (41), and the internal diameter of a fixed section of thick bamboo (31) is less than the internal diameter of trunk line (11), and compression spring (43) are installed to the one end that sealed near-end was kept away from in a sealed section of thick bamboo (42), and compression spring (43) cover is established on drawing penetrating pipe (23), and compression spring (43) and a fixed section of thick bamboo (31) are close to the terminal surface butt of trunk line (11).

5. A hydrogen gas closed circulation system for a fuel cell according to claim 1, characterized in that: draw the inside cavity of ejector tube (23) to draw and penetrate passageway (6), draw and penetrate passageway (6) including toper passageway (62) and reduce passageway (61), toper passageway (62) are located and draw ejector tube (23) to keep away from the one end department of another injection joint (2), the diameter at toper passageway (62) both ends varies, toper passageway (62) and the one end that reduces passageway (61) position adjacent are the one end that the diameter is little, and the diameter that reduces passageway (61) is less than the one end that toper passageway (62) diameter is little, the diameter that reduces passageway (61) on air inlet connector (21) is less than the diameter that reduces passageway (61) on air outlet connector (22).

6. A hydrogen gas closed circulation system for a fuel cell according to claim 1, characterized in that: an extension pipe (24) is integrally formed at one end of the injection pipe (23) far away from the other injection joint (2).

7. A hydrogen gas closed circulation system for a fuel cell according to claim 3, characterized in that: the included angle between the axis of the side pipeline (12) and the axis of the main pipeline (11) is an acute angle, and the side pipeline (12) inclines towards one side of the air outlet joint (22).