Top liquid inlet pipe structure of low-temperature liquid tank

Abstract

The utility model discloses a top liquid inlet pipe structure of a low-temperature liquid tank box, the liquid tank box is provided with an outer tank body, an inner tank body and a liquid inlet pipe, and a liquid inlet end is positioned at the upper part in the inner tank body and is positioned above the liquid level of the highest liquid level allowed to be contained in the inner tank body; the liquid inlet end is provided with an impact dispersion structure which meets large-flow liquid inlet and dispersedly distributes flowing liquid in the upper space of the inner tank body; the impact dispersion structure increases the gas-phase contact area between the inflowing inlet liquid and the top of the inner tank body and enhances the mass transfer effect through the mutual impact between the fluid and the impact surface with a specific shape or between the fluids; and the gas in the gas phase space is re-liquefied. The guiding semi-closed plate and the impact surface which are arranged at the outlet end can impact and deflect inflowing liquid flow for multiple times, so that the liquid is dispersed, the contact area between the liquid and a gas phase in the tank is increased, the gas in the gas phase space can be cooled, the gas in the gas phase space is liquefied again, the pressure in the tank body is reduced, and the service life of the tank body is prolonged. Therefore, gas emission can be reduced.

Description

Technical Field

[0001] This utility model relates to the field of cryogenic transport tank technology, specifically to a top liquid inlet pipe structure for a cryogenic liquid tank. Background Technology

[0002] Cryogenic tank containers are specially designed for transporting and storing cryogenic liquids. These liquids typically include liquefied natural gas (LNG), liquid oxygen, liquid nitrogen, and liquid argon. The design of cryogenic tank containers requires special consideration of material selection and the application of insulation technology to ensure that the extremely low temperature of the internal substances can be maintained during long-term transportation, preventing evaporation loss.

[0003] When using high-vacuum multi-layer insulated cryogenic liquid tank trucks for transportation, the tanks need to be filled with liquid before transport. A top liquid inlet pipe is installed at the top of the container inside the tank.

[0004] Patent application number 201910717553.1 discloses a marine storage tank, comprising a tank body and an external liquid inlet pipe and an internal liquid inlet pipe disposed on the tank body. The internal liquid inlet pipe is located inside the inner tank, its top end connecting to the external liquid inlet pipe, and extends along the top to the bottom of the inner tank. The internal liquid inlet pipe is curved along the contour of the inner wall of the inner tank, and the degree of curvature of the internal liquid inlet pipe is adapted to the contour of the inner wall of the inner tank; the central angle corresponding to the internal liquid inlet pipe is greater than 180 degrees. This method involves inserting the liquid inlet pipe into the bottom of the cryogenic tank for liquid inlet operation. While this avoids disturbing the upper liquid layer, this method also has some obvious disadvantages and potential risks; specifically: 1. It easily damages the tank bottom: Especially for cryogenic tanks used in special transportation operations, the long-term impact on the same position at the bottom during liquid inlet may cause physical damage to the tank bottom. 2. Localized supercooling caused by the flushing of cryogenic liquids: When cryogenic liquids are directly sprayed onto the bottom of the tank, the local temperature at the bottom may drop sharply. This not only affects the thermal stress distribution of the tank material but may also increase the material's cold brittleness, leading to problems such as cracking. 3. Increased evaporation rate: Although directly introducing liquid from the bottom reduces surface disturbance, this method may cause a sudden increase in pressure inside the tank, thus increasing the evaporation rate, especially when handling volatile cryogenic liquids.

[0005] In view of the above, it is necessary to propose a top inlet pipe structure for cryogenic liquid tanks to solve the above problems. Utility Model Content

[0006] The purpose of this invention is to overcome the defects in the existing technology and provide a top liquid inlet pipe structure for a cryogenic liquid tank.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows: A top inlet pipe structure for a cryogenic liquid tank, the liquid tank having an outer tank and an inner tank, with an inlet pipe passing sequentially through the outer tank and the inner tank from the outside of the liquid tank. The inlet pipe is located at the end of the inner tank as the inlet end, which is located at the upper part of the inner tank and above the highest liquid level that the inner tank can hold. The inlet end is provided with an impact dispersion structure that satisfies large-flow liquid inlet and disperses the flowing liquid in the upper space of the inner tank. The impact dispersion structure increases the contact surface between the inflowing liquid and the gas phase at the top of the inner tank and enhances the mass transfer effect through the collision between the fluid and a specific shaped impact surface or the mutual collision between the fluids; thus reliquefying the gas in the gas phase space.

[0008] Furthermore, the impact dispersion structure includes a guide semi-enclosed plate. The liquid inlet end is processed to form a first oblique cut and a second oblique cut. The first oblique cut and the second oblique cut are located on the upper and lower sides of the liquid inlet pipe end, respectively. The first oblique cut is on the lower side and forms an angle α with the horizontal plane, and the second oblique cut is on the upper side and forms an angle b with the horizontal plane. The guide semi-enclosed plate is set on the first oblique cut, making the second oblique cut open, so that the liquid inlet end forms a semi-enclosed opening. After the liquid flow impacts the guide semi-enclosed plate, it is deflected and sprayed out through the second oblique cut. The second oblique cut faces the inner wall of the top of the inner tank. After the liquid flow is impacted a second time by the top wall of the inner tank, it is deflected downward again and distributed in a scattering manner in the upper space of the tank.

[0009] Furthermore, the included angles a and b range from 30° to 60°; a flow gap is left between the lower end of the guide semi-enclosed plate and the lower end of the first oblique cut; the upper half of the straight pipe near the liquid inlet end is provided with spray holes at intervals along the circumference; the middle part of the liquid inlet pipe is provided with a U-shaped pipe section that is bent downwards on the horizontally set straight pipe section.

[0010] Furthermore, the liquid inlet pipe is provided with a straight pipe section along the axial direction of the tank body, and ribs are respectively branched on both sides of the straight pipe section. The ends of the ribs on both sides are liquid inlet ends, and the ends of the ribs on both sides are arranged opposite each other, so that the liquid flow sprayed from the ends of the ribs on both sides collides with each other to form an impact dispersion structure.

[0011] Furthermore, the height of the liquid inlet is located at the midpoint between the highest liquid level and the inner top surface of the inner tank.

[0012] Furthermore, the impact dispersion structure includes an air intake chamber, one end of which is connected to a liquid inlet pipe and the other end is provided with a throat pipe. The liquid inlet pipe is connected to a nozzle that passes through the air intake chamber, the end of which points to the throat pipe. The other end of the throat pipe is provided with a cone-shaped diffuser pipe with a gradually increasing diameter. The circumferential sidewall of the air intake chamber is provided with an air inlet.

[0013] Furthermore, the impact surface includes an arc-shaped dispersion base disposed on the top wall of the inner tank at the liquid ejection impact position, and the arc-shaped dispersion base has an arc-shaped concave surface on the side facing the liquid inlet end.

[0014] Furthermore, the center of the arc-shaped concave surface is provided with a cone-shaped tip that bulges toward the liquid outlet end.

[0015] Furthermore, the inlet pipe is provided with a float valve structure on the side of the U-shaped tube away from the inlet end to prevent the liquid flow from moving in the opposite direction. The float valve structure includes a connecting pipe with threaded connection ends at both ends for connecting the inlet pipes at the front and rear ends. The connecting pipe is provided with a valve core structure inside. The valve core structure includes a sealing element and a floating core that moves freely along the axial direction. The floating core moves towards the sealing element under the push of the liquid remaining in the U-shaped tube and seals with it to close the inlet pipe.

[0016] Furthermore, the connecting pipe has a chamber with an enlarged diameter in the middle, and the floating core moves in the enlarged chamber. The floating core includes an axial guide rod and an inclined conical surface. The axial guide rod passes through the inclined conical surface along the axis, and the inclined conical surface cooperates with the sealing element. The floating valve structure also includes a guide frame, and the guide frame has a guide hole at least at the center of the connecting pipe for the axial guide rod to pass through.

[0017] The advantages and beneficial effects of this utility model are as follows: Compared with the traditional liquid inlet pipe, the top liquid inlet pipe structure of the cryogenic liquid tank of this utility model can achieve multiple impacts and deflections of the incoming liquid flow by the guide semi-enclosed plate and impact surface at the outlet end, thereby dispersing the liquid and increasing the contact area with the gas phase inside the tank. This can cool the gas in the gas phase space, thereby realizing the re-liquefaction of the gas in the gas phase space, reducing the internal pressure of the tank, and thus reducing gas emissions.

[0018] The opposing ribbed tube design allows for liquid collisions, preventing liquid from impacting the inner tank surface and thus avoiding any influence on the tank's surface area. Multiple sets of ribbed tubes can be arranged within the tank so that during feeding, all points in the internal gas phase space can connect with the incoming liquid phase, further increasing the heat exchange area with the gas phase.

[0019] The floating valve structure effectively prevents backflow of liquid from affecting facilities such as the feed pipeline and feed pump when the pressure inside the tank rises abnormally. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the top liquid inlet pipe structure of a cryogenic liquid tank according to this utility model;

[0021] Figure 2 This is a detailed drawing of the top liquid inlet pipe in this utility model;

[0022] Figure 3 This utility model Figure 2 A magnified view of the area in the center circle;

[0023] Figure 4 This utility model Figure 3 A front view along direction A;

[0024] Figure 5 This utility model Figure 2 Schematic diagram of the structure of section BB;

[0025] Figure 6 This is one of the structural schematic diagrams of the arc-shaped dispersion base in this utility model;

[0026] Figure 7 This is the second schematic diagram of the arc-shaped dispersion base in this utility model;

[0027] Figure 8 This is a front view of the ribbed tubular top liquid inlet pipe structure of this utility model;

[0028] Figure 9 This is a side view of the ribbed tubular top liquid inlet pipe structure of this utility model;

[0029] Figure 10 This is a schematic diagram of the impact dispersion structure in the fourth embodiment of this utility model;

[0030] Figure 11 This is a structural schematic diagram of the fifth embodiment of this utility model;

[0031] Figure 12 This is a schematic diagram of the float valve structure in this utility model;

[0032] Figure 13 This utility model Figure 12 Schematic diagram of section AA;

[0033] In the diagram: 1. Inner tank; 2. Inlet pipe; 3. Inlet end; 4. Impact dispersion structure; 5. Impact surface; 6. Guide semi-enclosed plate; 7. First oblique cut; 8. Second oblique cut; 9. Angle a; 10. Angle b; 11. Flow gap; 12. Injection hole; 13. U-shaped tube section; 14. Straight tube section; 15. Ribbed tube; 16. Suction chamber; 17. Throat; 18. Nozzle; 19. Diffuser tube; 2 0. Air inlet; 21. Arc-shaped dispersion base; 22. Arc-shaped concave surface; 23. Conical tip; 24. Floating valve structure; 25. Connecting pipe; 26. Threaded connection end; 27. Seal; 28. Floating core; 29. ​​Enlarged chamber; 30. Axial guide rod; 31. Inclined conical surface; 32. Guide frame; 33. Guide hole; 34. Pressure measuring tube; 35. Pressure gauge gas phase tube; 36. Outer ring; 37. Support rod. Detailed Implementation

[0034] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0035] Example 1:

[0036] A top inlet pipe structure for a cryogenic liquid tank, the liquid tank comprising an outer tank and an inner tank 1, such as... Figure 1 As shown, an inlet pipe 2 is provided from the outside of the liquid tank, passing through the outer tank body and the inner tank body 1 in sequence. The inlet pipe 2 is located at the end of the inner tank body 1 as the inlet end 3. The inlet end 3 is located in the upper part of the inner tank body 1 and is above the highest liquid level that the inner tank body 1 can hold. The inlet end 3 is provided with an impact dispersion structure 4 to meet the large flow of liquid and to disperse the flowing liquid in the upper space of the inner tank body 1. The impact dispersion structure 4 increases the contact surface between the inflowing liquid and the gas phase at the top of the inner tank body 1 and enhances the mass transfer effect through the impact surface 5 of a specific shape between the fluid and the fluid or the mutual impact between the fluids. This causes the gas in the gas phase space to be reliquefied.

[0037] Specifically, such as Figure 3 As shown, the impact dispersion structure 4 includes a guide semi-enclosed plate 6. The liquid inlet end 3 is machined to form a first oblique cut 7 and a second oblique cut 8. The first oblique cut 7 and the second oblique cut 8 are located on the upper and lower sides of the end of the liquid inlet pipe 2, respectively. The first oblique cut 7 is on the lower side and forms an angle α9 with the horizontal plane, and the second oblique cut 8 is on the upper side and forms an angle b10 with the horizontal plane. The guide semi-enclosed plate 6 is disposed on the first oblique cut 7, making the second oblique cut 8 an opening, so that the liquid inlet end 3 forms a semi-enclosed opening. After impacting the guide semi-enclosed plate 6, the liquid flow is deflected and sprayed out through the second oblique cut 8, such as... Figure 2 , 3 As shown, when the fluid enters the inner tank 1 through the inlet pipe 2 and reaches the inlet end 3, it first collides with the guide semi-enclosed plate 6 on the first oblique cut 7. This guide semi-enclosed plate 6 can perform the first flow deflection and guidance of the fluid, and form a pressure release at the outlet end. After the first collision, a certain diffusion effect can be formed. The second oblique cut 8 faces the top inner wall of the inner tank 1. In order to meet the large flow rate of fluid entering and not cause pressure buildup in the inlet pipe 2 at the inlet end 3, the upper second oblique cut 8 enlarges the opening area of ​​the fluid outflow, so that more fluid can enter the inner tank 1. Figure 1As shown, the liquid flow is deflected downwards again by the second impact on the top wall of the inner tank 1 and is distributed in a scattering pattern in the upper space of the tank. In this embodiment, the top wall of the inner tank 1 forms an impact surface 5 for collision. At this time, the fluid is deflected downwards after the impact, thereby contacting the gas phase in the gas phase space inside the tank. After two collisions, the fluid entering the inner tank 1 through the inlet pipe 2 is further impacted and dispersed, further increasing the contact area with the gas phase and forming a better contact effect with the gas phase.

[0038] A top liquid inlet pipe 2 is installed at the top of the container inside the tank. During the filling process, since there is a gas phase space of about 5-10% at the top, the liquid inlet pipe can effectively cool the gas in the gas phase space, thereby achieving gas re-liquefaction, reducing the internal pressure of the container inside the tank, and reducing gas emissions. The top liquid inlet pipe 2 has a semi-sealed opening design, so that the liquid entering through the top liquid inlet pipe 2 is sprayed into the inner container in a timely manner. Figure 1 As shown, in actual use, the inner tank 1 is also equipped with a pressure measuring tube 34 for connecting a pressure gauge, and a pressure gauge vapor phase tube 35 is installed in the inner tank 1 to facilitate observation of the internal pressure of the inner container during transportation. In the design, the inlet pipe 2 faces the pressure gauge vapor phase tube 35, which makes it easy for liquid to splash into the pressure measuring tube 34 during liquid filling. The traditional sealing plate directly blocks it, which will cause the pressure gauge reading set on the front end cap to be inaccurate, thus affecting the safety of the tank truck. To address this problem, this embodiment optimizes the design of the liquid outlet at the top inlet end by changing the liquid flow direction and adopting a slanted structure. This solves the problem of the liquid in the pressure gauge vapor phase tube 35 affecting the pressure gauge. After multiple deflections, it not only avoids the port of the pressure measuring tube 34, but also makes the fluid distribution more dispersed during collision, increasing the gas phase contact area; it also reduces the internal pressure of the container inside the tank during filling and reduces gas emission.

[0039] In some embodiments, the included angles a9 and b10 range from 30° to 60°; as a preferred embodiment, such as Figure 3 As shown in the figure above, both included angles a9 and b10 are designed at 45°, and a flow gap 11 is left between the lower end of the guide semi-enclosed plate 6 and the lower end of the first oblique cut 7; Figure 4 As shown, specifically, a 3mm gap is left at the bottom of the pipe opening to prevent impurities in the liquid coming from the top, facilitating its flow out from the bottom notch. As can be seen from the flow direction arrow at the pipe opening, the liquid will not directly enter the gas phase tube 35 of the pressure gauge after flowing out, thus protecting the pressure gauge and making the pressure gauge reading more accurate. Figure 2 , 5As shown, the upper half of the straight pipe section 14 near the liquid inlet end 3 is provided with spray holes 12 at intervals along the circumference. In addition to the guide semi-enclosed plate 6 at the end of the liquid inlet pipe 2, the spray holes 12 with upward openings are added. This can not only increase the flow rate into the tank, but also allow the fluid to be sprayed upwards and impact the top wall of the inner tank 1 to form a collision diffusion. In actual use, in order to avoid the wear of the inner tank 1 surface by the fluid impact, a thickened plate can be provided at the fluid collision part.

[0040] Example 2:

[0041] As an improvement to the thickened plate described in the foregoing embodiments, such as Figure 6 As shown, the impact surface 5 includes an arc-shaped dispersion base 21 located on the top wall of the inner tank 1 at the liquid ejection impact position. The arc-shaped dispersion base 21 has an arc-shaped concave surface 22 on the side facing the liquid inlet end 3. In this embodiment, the range of the arc-shaped concave surface 22 should cover the area formed after the fluid is ejected from the liquid inlet end 3 when the fluid changes within a certain pressure range. The middle part of the arc-shaped concave surface 22 is arched upward, and the edge position is relatively low, so that the ejected liquid is deflected by the arc-shaped concave surface 22 and covers the diffusion range along the direction of the tangent of the edge of the arc-shaped concave surface 22, forming a curtain-like diffusion. This increases the gas phase contact area and can also effectively avoid the pressure gauge gas phase pipe 35.

[0042] Furthermore, as a preferred embodiment, such as Figure 7 As shown, the concave surface 22 has a cone tip 23 protruding towards the liquid outlet in the middle. The cone tip 23 is formed in the middle of the concave surface so that the sprayed liquid can first hit the cone tip 23 and form a preliminary dispersion. It can be understood that the cone tip 23 can be point-shaped or prismatic. When the fluid passes through the semi-enclosed plate 6 of the liquid inlet end 3 for the first deflection, it can form a jet with a certain fan-shaped expansion angle. Thus, the prismatic cone tip 23 can be used to cover the fan-shaped expansion angle of the jet.

[0043] Preferably, the liquid inlet pipe 2 has a downwardly curved U-shaped section 13 on the horizontally arranged straight pipe section 14 in the middle. In actual use, a certain amount of liquid can be held in the U-shaped section 13, which can enhance the sealing effect of the liquid inlet pipe 2 after feeding is completed.

[0044] Example 3:

[0045] The inlet pipe 2 has a straight pipe section 14 along the axial direction of the tank body. Rib pipes 15 branch off from both sides of the straight pipe section 14. In actual use, a pair of rib pipes 15 on each side constitutes a set. Only one set can be provided, or multiple sets can be provided, such as... Figure 8 , 9As shown, the ends of the two rib tubes 15 are liquid inlet ends 3. The ends of the two rib tubes 15 are arranged opposite each other, so that the liquid streams ejected from the ends of the two rib tubes 15 collide with each other to form an impact dispersion structure 4. Figure 8 The diagram shows several sets of ribbed tubes 15 arranged at intervals along the straight tube section 14, as shown. Figure 9 As shown, the ends of the two rib tubes 15 are arranged opposite each other. When liquid is introduced, the liquid is sprayed out from the liquid inlet end 3 opposite to each other, so that the liquid collides with the liquid and then forms diffusion and increases the contact area with the gas phase.

[0046] Preferably, the height of the liquid inlet end 3 is located at the midpoint between the highest liquid level and the inner top surface of the inner tank 1. For example... Figure 9 As shown, the inlet pipe 2 extends downward into the inner tank 1 to a certain depth, so that the straight pipe section 14 can be located in the inner tank 1 and at a certain distance from the top. Therefore, when liquid is introduced, as the liquid level rises, the liquid level can submerge the straight pipe section 14. During the feeding process of the fluid through the straight pipe section 14, due to the immersion design of the straight pipe section 14, the original low-temperature liquid in the inner tank 1 can exchange heat with the incoming fluid. It can be understood that the external liquid flowing in is slightly heated or a small amount of fluid vaporizes due to the influence of the external temperature outside the tank. After being cooled and heat exchanged by the submerged straight pipe section 14, the inlet liquid temperature can be maintained at a low level. Furthermore, some gas carried by the incoming fluid can be liquefied in the straight pipe section 14, and will not form a gaseous ejection. It is understandable that in this embodiment, the straight pipe section 14 does not need to be located at a low position. Since the space in the inner tank 1 is large at the initial stage of feeding, the pressure rise in the tank caused by the liquid feeding is slow. However, as the feeding increases and the liquid level rises, the space at the top of the tank is greatly reduced. At this time, it is necessary to pay attention to controlling the pressure inside the tank. Therefore, after the liquid level rises to a certain position, making the liquid level submerge the straight pipe section 14 can effectively deal with the problem of the rapid increase in pressure inside the tank during liquid feeding.

[0047] Example 4:

[0048] The impact dispersion structure 4 includes an air intake chamber 16, one end of which is connected to a liquid inlet pipe 2, and the other end is provided with a throat pipe 17. The liquid inlet pipe 2 is connected to a nozzle 18 that passes through the air intake chamber 16, with the end of the nozzle 18 pointing towards the throat pipe 17. The other end of the throat pipe 17 is provided with a cone-shaped diffuser pipe 19 with a gradually increasing diameter. The circumferential sidewall of the air intake chamber 16 is provided with an air inlet 20. Figure 10As shown, in this embodiment, a Venturi jet structure is formed by the arrangement of the throat 17 and the diffuser 19. When the fluid is injected into the throat 17 from the nozzle 18, and then the pressure drops sharply through the diffuser 19, a relative negative pressure zone is formed in the suction chamber 16. In this way, the gaseous medium in the gas phase space above the liquid surface can be absorbed into the air inlet 20 arranged around the perimeter. The gas phase and the fluid are mixed by mutual compression and collision at the throat 17 and the diffuser 19. During this process, temperature is transferred, so that the absorbed gas phase is transformed into liquid phase, thereby reducing the pressure in the gas phase space inside the tank and reducing the gas emission during the feeding process. It can be understood that this embodiment can be applied to the position of the liquid inlet 3 in the aforementioned embodiments.

[0049] Example 5:

[0050] like Figure 11 As shown, the inlet pipe 2 is provided with a float valve structure 24 on the side of the U-shaped pipe section 13 away from the inlet end 3 to prevent the liquid flow from moving in the opposite direction. The float valve structure 24 plays a role in preventing liquid backflow and avoiding liquid backflow impacting the front end device of the inlet pipe 2.

[0051] The floating valve structure 24 includes a connecting pipe 25, with threaded connection ends 26 at both ends of the connecting pipe 25 connecting to the inlet pipes 2 at the front and rear ends. Inside the connecting pipe 25 is a valve core structure, which includes a sealing element 27 and a floating core 28 that moves freely along the axial direction. The floating core 28 moves towards the sealing element 27 under the pressure of the liquid remaining in the U-shaped tube 13 and seals with it to close the inlet pipe 2. Figure 11-13 As shown, during liquid inlet, the liquid pushes the floating core 28 to the left. At this time, the floating valve structure 24 is in the open state. If the internal pressure of the tank increases, the floating core 28 is only pushed by the reverse flow of gas. The pushing force formed by the gas is small. In this embodiment, the floating valve structure 24 is combined with the U-shaped tube 13. When the internal pressure increases, the liquid inside the U-shaped tube is squeezed first. When the liquid moves in the inlet pipe 2, the force it exerts on the floating core 28 is large, which can firmly press the floating core 28 against the sealing element 27, thereby forming a better sealing performance.

[0052] Specifically, the connecting pipe 25 has an enlarged chamber 29 in the middle. The floating core 28 moves within the enlarged chamber 29. The enlarged chamber 29 can accommodate large-flow feeding without reducing the effective feed cross-sectional area of ​​the inlet pipe 2. The floating core 28 includes an axial guide rod 30 and a conical surface 31. The axial guide rod 30 passes through the conical surface 31 along the axis, and the conical surface 31 cooperates with the seal 27. The float valve structure 24 also includes a guide frame 32. The guide frame 32 has a guide hole 33 at least at the center of the connecting pipe 25 for the axial guide rod 30 to pass through. Through the cooperation of the guide rod and the guide frame 32, the floating core 28 can be accurately positioned and move strictly along the axis, thereby ensuring perfect contact and sealing between the conical surface 31 and the seal 27. Figure 13 As shown, the guide frame 32 includes an outer ring 36 and support rods 37. The outer ring 36 is concentrically arranged with the guide hole 33, and multiple support rods 37 are arranged between them for fixation. In actual use, an internal thread can be formed on the inner wall of the connecting pipe 25, and an external thread can be formed on the outer wall of the outer ring 36, so that the guide frame 32 is installed in the float valve structure 24 by means of threaded connection. This can achieve the advantages of easy installation and easy adjustment of axial position, thereby controlling and adjusting the movement stroke of the floating core 28.

[0053] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A top liquid inlet pipe structure of a low-temperature liquid tank, the liquid tank being provided with an outer tank body and an inner tank body (1), a liquid inlet pipe (2) being provided outside the liquid tank and sequentially passing through the outer tank body and the inner tank body (1), characterized in that, The liquid inlet pipe (2) is located at the end of the inner tank body (1) as a liquid inlet end (3), the liquid inlet end (3) is located at the upper part inside the inner tank body (1) and above the highest liquid level of the liquid allowed to be contained in the inner tank body (1); the liquid inlet end (3) is provided with an impact dispersion structure (4) satisfying large flow liquid inlet and dispersing the liquid flowing through on the upper space of the inner tank body (1); the impact dispersion structure (4) increases the contact area of the liquid flowing in with the gas phase on the top of the inner tank body (1) through the impact between the fluid and the specific shape of the impact surface (5) or the mutual impact between the fluids and enhances the mass transfer effect; and the gas in the gas phase space is liquefied again.

2. A top fill tube structure for a cryogenic liquid tank in accordance with claim 1, wherein, The impact dispersion structure (4) comprises a guide semi-closed plate (6), the liquid inlet end (3) is processed to form a first oblique cut (7) and a second oblique cut (8), the first oblique cut (7) and the second oblique cut (8) are respectively located at the upper and lower sides of the end of the liquid inlet pipe (2), the first oblique cut (7) is located at the lower side and forms an angle a (9) with the horizontal plane, the second oblique cut (8) is located at the upper side and forms an angle b (10) with the horizontal plane; the guide semi-closed plate (6) is arranged on the first oblique cut (7), the second oblique cut (8) is opened, the liquid inlet end (3) forms a semi-closed opening, the liquid flow is turned after impinging on the guide semi-closed plate (6) and is sprayed out through the second oblique cut (8), the second oblique cut (8) faces the inner wall on the top of the inner tank body (1), the liquid flow is turned downward again after the second impingement on the top wall of the inner tank body (1) and is scattered and distributed in the upper space of the tank.

3. A top fill tube arrangement for a cryogenic liquid tank according to claim 2, wherein, The angle range of the angle a (9) and the angle b (10) is 30° to 60°; a flow gap (11) is left between the lower end of the guide semi-closed plate (6) and the lower end of the first oblique cut (7); the upper half of the straight pipe part (14) close to the liquid inlet end (3) is provided with spray holes (12) at intervals in the circumferential direction; a U-shaped pipe part (13) is arranged downwardly on the horizontally arranged straight pipe part (14) in the middle of the liquid inlet pipe (2).

4. A top fill tube structure for a cryogenic liquid tank in accordance with claim 1 wherein, The liquid inlet pipe (2) is provided with a straight pipe part (14) in the axial direction of the tank body, rib pipes (15) are respectively arranged at the two sides of the straight pipe part (14), the liquid inlet ends (3) are arranged at the ends of the two rib pipes (15), and the ends of the two rib pipes (15) are oppositely arranged to make the liquid flows sprayed out from the ends of the two rib pipes (15) collide with each other to form the impact dispersion structure (4).

5. A top fill tube arrangement for a cryogenic liquid tank according to claim 4, wherein, The height position of the liquid inlet end (3) is at the middle position between the highest liquid level and the inner top surface of the inner tank body (1).

6. A top fill tube arrangement for a cryogenic liquid tank according to any one of claims 1, 4 or 5, wherein, The impact dispersion structure (4) comprises an air suction chamber (16), one end of the air suction chamber (16) is connected with the liquid inlet pipe (2), the other end of the air suction chamber (16) is provided with a throat pipe (17), the liquid inlet pipe (2) is connected with a nozzle (18) penetrating through the air suction chamber (16), the end of the nozzle (18) points to the throat pipe (17), the other end of the throat pipe (17) is provided with a diffusion pipe (19) which is tapered and gradually increases in diameter, and the circumferential side wall of the air suction chamber (16) is provided with an air inlet (20).

7. A top fill tube arrangement for a cryogenic liquid tank according to claim 2, wherein, The impact surface (5) comprises an arc-shaped dispersion base (21) arranged at the top wall of the inner tank (1) at the liquid ejection impact position, and the arc-shaped dispersion base (21) is provided with an arc-shaped concave surface (22) on the side facing the liquid inlet end (3).

8. A top fill tube arrangement for a cryogenic liquid tank according to claim 7, wherein, The arc-shaped concave surface (22) is provided with a tapered tip (23) protruding towards the liquid outlet end.

9. A top fill tube structure for a cryogenic liquid tank in accordance with claim 3 wherein, The liquid inlet pipe (2) is provided with a float valve structure (24) at the side of the U-shaped pipe portion (13) away from the liquid inlet end (3) to prevent the reverse movement of the liquid flow, and the float valve structure (24) comprises a connecting pipe (25), both ends of the connecting pipe (25) are provided with threaded connection ends (26) connected with the liquid inlet pipe (2), the connecting pipe (25) is internally provided with a valve core structure, the valve core structure comprises a sealing element (27) and a floating core portion (28) freely moving in the axial direction, the floating core portion (28) is pushed by the liquid retained in the U-shaped pipe portion (13) to move towards the sealing element (27) and seal the liquid inlet pipe (2) by sealing cooperation.

10. A top fill tube structure for a cryogenic liquid tank in accordance with claim 9, wherein, The middle part of the connecting pipe (25) is provided with an enlarged diameter cavity (29), the floating core portion (28) moves in the enlarged diameter cavity (29), the floating core portion (28) comprises an axial guide rod (30) and an inclined tapered surface (31), the axial guide rod (30) is arranged through the inclined tapered surface (31) along the axis, and the inclined tapered surface (31) is matched with the sealing element (27); the float valve structure (24) further comprises a guide frame (32), and the guide frame (32) is provided with a guide hole (33) through which the axial guide rod (30) passes at least at the center of the connecting pipe (25).

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