Liquid level measuring instrument for low temperature container and using method thereof

Abstract

The present invention relates to the field of liquid level measurement technology, and specifically discloses a liquid level measuring instrument for a cryogenic container and a method of use, comprising a gas phase tube, a liquid phase tube and a liquid level gauge; the portion of the liquid phase tube extending into the cryogenic container comprises: a straight tube section, arranged in the inner tank of the cryogenic container; the straight tube section comprises an opening section with a first exhaust hole and a light tube section without an opening, and the end of the light tube section is a closed end; a drainage tube, arranged at the top of the light tube section close to the opening section, the drainage tube is connected to the light tube section; a flow guide, arranged in the drainage tube, the width of the flow guide gradually increases from bottom to top, and a drainage cavity is formed between the flow guide and the drainage tube; a sealing section, which is penetrated on the side wall of the inner tank; one end of the sealing section is connected to the opening section; a U-shaped gas sealing section, arranged in the vacuum interlayer of the cryogenic container, one end is connected to the other end of the sealing section, and the other end is connected to the heating section. The present invention can improve the accuracy and stability of the differential pressure liquid level instrument when used for liquid level measurement of a cryogenic container.

Description

Technical Field

[0001] The invention relates to the technical field of liquid level measurement, and in particular to a liquid level measuring instrument for a low-temperature container and a use method thereof. Background Art

[0002] The storage temperature of cryogenic medium (cryogenic liquefied gas) is generally below -40°C, for example, the storage temperature of liquefied natural gas (LNG) is about -160°C. Cryogenic containers for storing cryogenic medium generally have an inner tank and an outer tank, with a vacuum interlayer between the inner tank and the outer tank to achieve the effect of heat insulation.

[0003] The differential pressure liquid level gauge is one of the most common liquid level measuring devices for cryogenic containers and can be used for horizontal and vertical cryogenic containers. The measuring principle of the differential pressure liquid level gauge is that the height difference of the liquid level will generate the static pressure of the liquid column. By detecting the different pressure values ​​at the upper and lower points of the liquid, the pressure difference between the two is obtained and then converted into the height difference of the liquid level. The differential pressure liquid level gauge mainly includes a liquid level gauge, a gas phase tube and a liquid phase tube. One end of the gas phase tube is connected to the top of the cryogenic container and the other end is connected to the liquid level gauge. One end of the liquid phase tube is connected to the bottom of the cryogenic container and the other end is connected to the liquid level gauge.

[0004] The structural design of the liquid phase tube in the differential pressure liquid level measuring instrument greatly affects the measurement accuracy of the differential pressure liquid level measuring instrument. CN212458541U discloses a low temperature container liquid level measuring device, which is provided with a liquid phase outlet tube at the sandwich end.

[0005] The spiral gas-sealing tube seals the liquid drawn out of the liquid phase outlet tube, and always seals the liquid in the spiral gas-sealing tube, which reduces the repeated fluctuations of the liquid level and improves the accuracy of the readings; the highest point of the gas-sealing tube is flush with the bottom of the inner tank, ensuring that the liquid surface pressure in the gas-sealing tube is the pressure at the lowest point of the inner tank, ensuring the accuracy of the readings. However, it has the following problems: when the external heat input is too large, the vaporized gas will push the gas-liquid boundary point into the liquid phase outlet tube, causing the liquid level in the liquid phase outlet tube to be lower than the lowest point of the inner tank, causing measurement errors.

[0006] CN113390487B discloses a differential pressure liquid level measurement system, a cryogenic medium storage tank and a tanker, wherein a differential pressure liquid phase pipe is extended to the bottom of the cryogenic medium storage tank, and the flat pipe of the differential pressure liquid phase pipe includes a hole pipe section with more than two holes on the pipe wall and a light pipe section at the end without holes, so that there is always liquid in the differential pressure liquid phase pipe, and the liquid level measurement point in the differential pressure liquid phase pipe is the lowest point of the cryogenic medium storage tank, and the stability of the liquid level measurement can be improved. However, when the external heat input is too large, it still cannot solve the problem of liquid level measurement stability. Summary of the invention

[0007] The object of the present invention is to provide a liquid level measuring instrument for a cryogenic container and a method of using the same, so as to improve the accuracy and stability of the differential pressure liquid level instrument when used for liquid level measurement of a cryogenic container.

[0008] The present invention is achieved through the following technical solutions:

[0009] A liquid level measuring instrument for a cryogenic container comprises a gas phase tube, a liquid phase tube and a liquid level gauge; the portion of the liquid phase tube extending into the cryogenic container comprises:

[0010] The straight pipe section is arranged in the inner tank of the low-temperature container; the straight pipe section includes an open-hole section with a first exhaust hole and a bare pipe section without an open hole, and the end of the bare pipe section is a closed end;

[0011] The drainage tube is arranged at the top of the light pipe section near the opening section, and the drainage tube is connected with the light pipe section;

[0012] A flow guide is arranged in the flow guide tube, the width of the flow guide increases gradually from bottom to top, and a flow guide cavity is formed between the flow guide and the flow guide tube;

[0013] The sealing section is arranged on the side wall of the inner tank; one end of the sealing section is connected to the opening section;

[0014] The U-shaped air sealing section is arranged in the vacuum interlayer of the low-temperature container, one end of the U-shaped air sealing section is connected to the other end of the sealing section, and the other end is connected to the heating section.

[0015] The present invention arranges a drainage tube on the light tube section of the straight tube section, and the drainage tube connects the inside and outside of the straight tube section. When the gas-liquid dividing point in the straight tube section moves to the drainage tube of the straight tube section, the drainage tube can divert the airflow in the straight tube section, and the first exhaust hole and the drainage tube form a secondary diversion, wherein, in the process of the airflow entering the straight tube section moving forward with the gas-liquid dividing point, a part of the airflow is guided out of the straight tube section through the first exhaust hole, thereby weakening the airflow in the straight tube section, and then a part of the airflow is guided out of the straight tube section through the drainage tube, that is, the arrangement of the drainage tube is further conducive to weakening the airflow in the light tube section entering the straight tube section, and can avoid liquid fluctuations in the light tube section caused by the high pressure of the airflow entering the light tube section, thereby improving the measurement stability of the liquid level measuring instrument. At the same time, the straight tube section extends into the inner tube, so that the liquid level measurement point in the light tube section is the lowest point of the low-temperature container, thereby ensuring that the measurement value of the liquid level meter is consistent with the actual liquid level height, thereby achieving the measurement accuracy of the liquid level measuring instrument.

[0016] In addition, a trumpet-shaped guide piece is provided in the drainage tube of the invention, and a drainage cavity is formed between the guide piece and the drainage tube, wherein the setting of the drainage cavity can quickly guide the airflow in the straight pipe section into the drainage tube, and the set guide piece utilizes the relatively low air pressure at the large end of the trumpet-shaped structure to accelerate the speed of the airflow through the drainage tube. The drainage tube and the guide piece of the present invention cooperate to guide as much airflow as possible through the drainage tube to reduce the fluctuation of the airflow on the low-temperature medium (liquid) in the light pipe section.

[0017] In summary, the present invention can improve the accuracy and stability of the differential pressure liquid level instrument when used for liquid level measurement of a cryogenic container.

[0018] In a preferred embodiment, it also includes:

[0019] The spiral section is arranged in the inner tank; one end of the spiral section is connected to the opening section, and the other end is connected to the sealing section; the liquid level height of the spiral section is the same as the liquid level height of the straight pipe section, and a plurality of second exhaust holes are arranged on the spiral section.

[0020] The present invention arranges a spiral section at the front end of the straight tube section, utilizes the spiral structure of the spiral section to prolong the time for the gas-liquid boundary point to enter the light tube end, and arranges a plurality of second exhaust holes on the spiral section, the second exhaust holes can guide a part of the airflow out of the liquid phase tube, and can further reduce the influence of the airflow on the low-temperature medium in the light tube.

[0021] In a preferred embodiment, the spiral segment includes a straight segment and an arc segment for connecting the straight segment, and the second exhaust holes on the arc segment are arranged radially.

[0022] In a preferred embodiment, the diameter of the second exhaust hole increases gradually from inside to outside, which is beneficial to increase the speed of airflow out of the spiral section, reduce the airflow entering the straight pipe section, and further reduce the impact of the airflow on the low-temperature medium in the light pipe.

[0023] In a preferred embodiment, a strip through groove is provided on the top of the light tube segment, and the drainage tube is connected with the light tube segment through the strip through groove. The drainage tube and the strip through groove have the same length, and the length of the drainage tube is greater than the inner diameter of the light tube segment, that is, the drainage tube has a larger cross-sectional channel, which can quickly guide the airflow in the straight tube segment and enable the drainage cavity to have a larger space, so that the airflow in the straight tube segment can be quickly diverted to the drainage tube.

[0024] In a preferred embodiment, there is a spacing between the bottom of the guide member and the top of the light tube segment to ensure that there is a larger space in the drainage cavity; the outlet end of the drainage tube is a trumpet-shaped structure, and the air pressure difference at both ends of the trumpet-shaped structure is used to accelerate the airflow out of the drainage tube; the diameter of the first exhaust hole tends to gradually increase from the inside to the outside.

[0025] In a preferred embodiment, the heating section includes a first heating tube and a second heating tube, and a first air guide tube and a second air guide tube, which are arranged in parallel. The first heating tube and the second heating tube are both provided with temperature sensors.

[0026] One end of the first heating tube and the second heating tube are connected by a first connecting tube, and the other end is connected by a second connecting tube; the first connecting tube is connected to the sealing section, and the second connecting tube is connected to an end section of the liquid phase tube close to the inner wall of the outer tank of the low-temperature container;

[0027] The first heating tube and the second heating tube are respectively wound with a first copper wire and a second copper wire; the first heating tube is provided with a first three-way valve between the first copper wire and the second connecting tube; the second heating tube is provided with a second three-way valve between the second copper wire and the second connecting tube;

[0028] One end of the first air guide pipe is connected to the first three-way valve, and the other end is connected to the second heating pipe, and the connection point is located between the second copper wire and the first connecting pipe, and a fourth one-way valve is provided on the first air guide pipe;

[0029] One end of the second air guide pipe is connected to the second three-way valve, and the other end is connected to the first heating pipe, and the connection point is located between the first copper wire and the first connecting pipe, and a third one-way valve is arranged on the second air guide pipe;

[0030] The third one-way valve, the fourth one-way valve, the first three-way valve, the second three-way valve, and the temperature sensor are all connected to the controller for communication.

[0031] In a preferred embodiment, a first one-way valve is provided on the first heating pipe between the first three-way valve and the second connecting pipe, and a second one-way valve is provided on the second heating pipe between the second three-way valve and the second connecting pipe;

[0032] The first one-way valve and the second one-way valve are both in communication with the controller.

[0033] The present invention improves the existing heating section and adopts two parallel heating routes, thereby avoiding the problem that the low-temperature medium in the liquid phase tube cannot be gasified when the heating copper wire fails to work.

[0034] The present invention can realize switching between two parallel heating routes through automatic control through the structural design of the heating section.

[0035] In a preferred embodiment, the liquid level height of the sealing section is the same as the liquid level height of the straight pipe section; the sealing section includes a horizontal steel pipe, the outer wall of the horizontal steel pipe is provided with an annular groove, a buffer sleeve is provided in the annular groove, and the outer wall of the buffer sleeve is provided with an elastic sealing strip that cooperates with the side wall of the inner tank.

[0036] The sealing section, spiral section and straight pipe section of the present invention have the same liquid level height. No matter where the gas-liquid dividing point in the liquid phase pipe is placed on the sealing section, spiral section and straight pipe section, it can ensure that the measured value of the liquid level meter is consistent with the actual liquid level height. Since the two ends of the low-temperature container are arc ends, when the sealing section is horizontally arranged and passes through the side wall of the inner tank, the conventional sealing connector can no longer meet the requirements of the sealing section passing through the side wall of the inner tank and being sealed with the inner tank. According to the characteristics that the sealing section, spiral section and straight pipe section are all horizontally arranged and abut against the bottom of the inner tank, the present invention improves the structure of the sealing section and no longer uses conventional sealing components. The sealing section of the present invention can both horizontally pass through and be sealedly connected to the side wall of the inner tank, and can abut against the bottom of the inner tank.

[0037] As in the method of using the liquid level measuring instrument, the low-temperature medium in the heating section is vaporized by heating the first copper wire or the second copper wire;

[0038] When the second copper wire is working, the controller controls the second three-way valve to connect the second heating pipe with the second connecting pipe, and the controller controls the fourth one-way valve to open and controls the first three-way valve to connect the first air guide pipe with the first heating pipe;

[0039] When the first copper wire is working, the controller controls the first three-way valve to connect the first air pipe with the second connecting pipe, and the controller controls the third one-way valve to open and controls the second three-way valve to connect the second air pipe with the second heating pipe.

[0040] The temperature sensor collects the temperature of the first heating tube and the second heating tube in real time and transmits the temperature to the controller, and the controller controls the first copper wire or the second copper wire to work.

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0042] 1. The present invention arranges a drainage tube on the light tube section of the straight tube section, and the drainage tube connects the inside and outside of the straight tube section. When the gas-liquid boundary point in the straight tube section moves to the drainage tube in the straight tube section, the drainage tube can divert the airflow in the straight tube section, which is beneficial to weaken the fluctuation of the airflow in the light tube section entering the straight tube section, and can avoid the fluctuation of the liquid in the light tube section caused by the large pressure of the airflow entering the light tube section, thereby improving the measurement stability of the liquid level measuring instrument. At the same time, the straight tube section extends into the inner tank, so that the liquid level measurement point in the light tube section is the lowest point of the low-temperature container, ensuring that the measurement value of the liquid level meter is consistent with the actual liquid level height, and realizing the measurement accuracy of the liquid level measuring instrument.

[0043] 2. The present invention adopts two parallel heating routes and can realize automatic control to switch between the two parallel heating routes; it can avoid the problem that the low-temperature medium in the liquid phase tube cannot be vaporized when the heating copper wire fails to work. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0045] Figure 1 It is a schematic diagram of the liquid level measuring instrument of the present invention installed on a cryogenic container;

[0046] Figure 2 A cross-sectional view of a straight pipe section of the present invention;

[0047] Figure 3 The structure of the heating section of the present invention is shown in FIG. Figure 1 ;

[0048] Figure 4 The structure of the heating section of the present invention is shown in FIG. Figure 2 ;

[0049] Figure 5 It is a schematic diagram of the structure of the spiral segment of the present invention;

[0050] Figure 6 It is a structural schematic diagram of the sealing section of the present invention.

[0051] Marks and corresponding parts names in the attached drawings:

[0052] 1-outer tank; 2-vacuum interlayer; 3-inner tank; 4-gas phase pipe; 5-liquid phase pipe; 6-liquid level gauge; 51-straight pipe section; 52-drainage tube; 53-spiral section; 54-sealing section; 55-U-shaped gas sealing section; 56-heating section; 57-flow guide; 58-drainage cavity; 511-strip groove; 512-first exhaust hole; 531-second exhaust hole; 541-horizontal steel pipe; 542-buffer sleeve; 543-elastic seal Seal; 561-first heating tube; 562-second heating tube; 563-first connecting tube; 564-second connecting tube; 565-first air duct; 566-second air duct; 567-first three-way valve; 568-second three-way valve; 5611-first copper wire; 5612-first one-way valve; 5621-second copper wire; 5622-second one-way valve; 5661-third one-way valve; 5671-fourth one-way valve. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. The schematic implementation mode of the present invention and its description are only used to explain the present invention and are not intended to limit the present invention. The embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0054] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to those of ordinary skill in the art that these specific details do not have to be employed to practice the present invention. In other embodiments, in order to avoid confusing the present invention, known structures, materials or methods are not specifically described. The materials, instruments and reagents used in the following examples, unless otherwise specified, can be obtained from commercial sources. The technical means used in the examples, unless otherwise specified, are conventional means well known to those skilled in the art.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0056] Embodiment 1:

[0057] CN113390487B discloses a differential pressure liquid level measurement system, a cryogenic medium storage tank and a tank truck. Although it also involves solving the measurement stability and accuracy of the differential pressure liquid level measurement system, the implementation method for improving the measurement stability is as follows: the differential pressure liquid phase tube is extended to the bottom of the cryogenic medium storage tank, and the flat pipeline of the differential pressure liquid phase tube includes a hole tube section with more than two holes opened on the tube wall and a light tube section at the end without holes, so as to ensure that there is always liquid in the differential pressure liquid phase tube, and the liquid level measurement point in the differential pressure liquid phase tube is the lowest point of the cryogenic medium storage tank, and the stability of the liquid level measurement can be improved. However, when the external heat input is too large, the hole pipe section cannot guide all the airflow out of the flat pipe in time, and there is still airflow entering the light pipe section. Since the end of the light pipe section is a closed end, the airflow and low-temperature medium entering the light pipe section cannot continue to move forward, and can only flow back to the hole pipe section and be discharged through the hole. At this time, the forward airflow and low-temperature medium collide with the returning airflow and low-temperature medium, resulting in large fluctuations in the airflow and low-temperature medium in the light pipe section; therefore, it still cannot solve the problem of liquid level measurement stability very well.

[0058] like Figure 1-Figure 6As shown, in order to solve the above problems, the present embodiment provides a liquid level measuring instrument for a cryogenic container, including a gas phase tube 4, a liquid phase tube 5 and a liquid level gauge 6, wherein one end of the gas phase tube 4 is connected to the liquid level gauge 6, and the other end is connected to the top of the cryogenic container, and one end of the liquid phase tube 5 is connected to the liquid level gauge 6, and the other end is connected to the bottom of the cryogenic container; the cryogenic container includes an outer tank 1 and an inner tank 3, and a vacuum interlayer 2 is formed between the outer tank 1 and the inner tank 3. The cryogenic container of the present embodiment is a horizontal structure, and the cryogenic container, the gas phase tube 4, and the liquid level gauge 6 are all prior arts, which are not improved in the present embodiment, and the liquid level gauge 6 is arranged on the outside of the outer tank 1; the present embodiment improves the structure of the liquid phase tube 5, mainly improving the part of the liquid phase tube 5 extending into the outer tank 1; specifically: the part of the liquid phase tube 5 extending into the cryogenic container includes:

[0059] The straight pipe section 51 is arranged in the inner tank 3; the axial direction of the straight pipe section 51 is parallel to the axial direction of the inner tank 3, and the straight pipe section 51 is in contact with the bottom of the inner tank 3; the straight pipe section 51 includes an open section with a first exhaust hole 512 and a bare pipe section without an open hole, wherein the open section is close to the sealed end of the inner tank 3, and the end of the bare pipe section away from the sealed end of the inner tank 3 is a closed end. The first exhaust hole 512 can guide a part of the airflow out of the straight pipe section 51, and weaken the airflow entering the light pipe section. Preferably, the diameter of the first exhaust hole 512 tends to gradually increase from the inside to the outside, that is, the first exhaust hole 512 is a trumpet-shaped structure. In the liquid, since the density of the liquid is greater than that of the gas, the gas discharge in the pipeline will encounter greater resistance; the extended shape of the trumpet tube is more conducive to the release of the gas in this case, because it can gradually slow down the speed of the airflow and reduce the resistance of the liquid to the airflow during the discharge process; and, when the airflow flows in from the small inlet, the speed will be very high, and when entering the larger outlet, the airflow speed will decrease, and the pressure will also decrease accordingly, that is, a pressure difference is formed between the inlet and outlet ends of the trumpet-shaped structure, which is conducive to the easier discharge of the gas; and this shape from small to large can reduce the impact of the airflow in a gradual manner, avoid the formation of vortices or pressure fluctuations near the outlet, and can make it easier to discharge the gas.

[0060] The drainage tube 52 is arranged at the top of the light tube section near the opening section, and the drainage tube 52 is connected to the light tube section; the drainage tube 52 can connect the internal space and the external space of the straight tube section 51, and guide the airflow in the straight tube section 51, so that the airflow that cannot be guided out from the first exhaust hole 512 can be diverted and guided out of the straight tube section 51 through the drainage tube 52, so as to reduce the airflow entering the light tube section, reduce the impact of the airflow on the low-temperature medium in the light tube section, and further reduce the fluctuation of the low-temperature medium in the light tube section, thereby providing measurement stability.

[0061] The guide member 57 is arranged in the drainage tube 52. The width of the guide member 57 gradually increases from bottom to top, and a drainage cavity 58 is formed between the guide member 57 and the drainage tube 52. On the one hand, the arrangement of the guide member 57 cannot affect the diversion effect of the drainage tube 52 on the airflow in the straight tube section 51. Therefore, the drainage cavity 58 is formed between the guide member 57 and the drainage tube 52, and the airflow in the straight tube section 51 is guided into the drainage tube 52 by the drainage cavity 58. At the same time, the trumpet-shaped guide member 57 can use the pressure difference at both ends to accelerate the airflow out of the drainage tube 52. In a specific case, there is a gap between the bottom of the guide member 57 and the top of the light tube section; the top of the guide member 57 is connected to the inner wall of the drainage tube 52.

[0062] In a preferred case, the outlet end of the drainage tube 52 is a trumpet-shaped structure, and a secondary acceleration structure is formed between the outlet end of the drainage tube 52 and the guide member 57 , which can further accelerate the airflow out of the drainage tube 52 .

[0063] The present embodiment is provided with the guide member 57 and the guide tube 52 having a trumpet-shaped structure, which can not only realize the air flow diversion, but also speed up the air flow diversion compared with the equal-diameter structure.

[0064] In a preferred case, in order to further improve the diversion effect of the drainage tube 52, a strip through groove 511 is provided on the top of the light tube segment, and the drainage tube 52 is connected to the light tube segment through the strip through groove 511. The drainage tube 52 and the strip through groove 511 have the same length, and the length of the drainage tube 52 is greater than the inner diameter of the light tube segment. Compared with the circular tubular drainage tube 52, the above arrangement can set the drainage tube 52 with a larger cross-section channel as much as possible to improve the diversion effect of the drainage tube 52, wherein the length of the drainage tube 52 refers to Figure 2 Horizontal direction in .

[0065] The sealing section 54 is passed through the side wall of the inner tank 3; one end of the sealing section 54 is connected to the opening section; in the present embodiment, in order to ensure that the sealing section 54 and the straight pipe section 51 are located in the same horizontal plane, that is, the two have the same liquid level height, the sealing section 54 includes a horizontal steel pipe 541, the outer wall of the horizontal steel pipe 541 is provided with an annular groove, a buffer sleeve 542 is provided in the annular groove, and the outer wall of the buffer sleeve 542 is provided with an elastic sealing strip 543 that cooperates with the side wall of the inner tank 3. Since both ends of the low-temperature container are arc ends, when the sealing section 54 is horizontally arranged and passes through the side wall of the inner tank 3, conventional sealing connectors can no longer meet the requirements of the sealing section passing through the side wall of the inner tank 3 and being sealed and connected to the inner tank 3. According to the characteristics that the sealing section 54 and the straight pipe section 51 are both horizontally arranged and abut against the bottom of the inner tank 3, this embodiment improves the structure of the sealing section 54, and no longer uses conventional sealing components. The sealing section 54 of this embodiment can both horizontally pass through and be sealed and connected to the side wall of the inner tank 3, and can abut against the bottom of the inner tank 3. The sealing section 54 of the present embodiment utilizes the elastic effect of the buffer sleeve 542 to achieve a sealed connection with the side wall of the inner tank 3, and according to the structural characteristics of the through hole opened in the side wall of the inner tank 3 for passing through the sealing section 54, since the side wall (sealed end) of the inner tank 3 is not a plane but an arc surface, the two ends of the through hole are not regular end surfaces but a shape adapted to the side wall of the inner tank 3. Therefore, the shape of the elastic sealing strip 543 of the present invention is also adapted to the side wall of the inner tank 3, so that the elastic sealing strip 543 is tightly attached to the inner end of the side wall of the inner tank 3. The elastic sealing strip 543 and the buffer sleeve 542 cooperate to improve the sealing effect. Both the elastic sealing strip 543 and the buffer sleeve 542 can be made of silicone.

[0066] The U-shaped gas sealing section 55 is arranged in the vacuum interlayer 2 of the low-temperature container, and the opening of the U-shaped gas sealing section 55 is arranged downward; one end of the U-shaped gas sealing section 55 is connected to the other end of the sealing section 54, and the other end of the U-shaped gas sealing section 55 is connected to the heating section 56, and the heating section 56 is used to heat and gasify the low-temperature medium in the liquid phase tube 5. Specifically, the heating section 56 can be implemented by copper wire heating; the heating section 56 is also arranged in the vacuum interlayer 2.

[0067] Embodiment 2:

[0068] like Figure 1-Figure 6 As shown, this embodiment is based on embodiment 1; the liquid level measuring instrument of this embodiment also includes:

[0069] The spiral section 53 is arranged in the inner tank 3; one end of the spiral section 53 is connected to the opening section, and the other end is connected to the sealing section 54; the liquid level of the spiral section 53 is the same as the liquid level of the straight tube section 51, and a plurality of second exhaust holes 531 are arranged on the spiral section 53. Specifically, the spiral section 53 includes a straight section and an arc section for connecting the straight section, and the second exhaust holes 531 on the arc section are arranged in the radial direction, that is, the axial direction of the second exhaust holes 531 is in the same direction as the radial direction of the arc section.

[0070] In a preferred case, the diameter of the second exhaust hole 531 tends to gradually increase from the inside to the outside.

[0071] In this embodiment, a spiral section 53 is provided at the front end of the straight tube section 51, and the spiral structure of the spiral section 53 is used to prolong the time for the gas-liquid boundary point to enter the light tube end. In addition, a plurality of second exhaust holes 531 are provided on the spiral section 53. The second exhaust holes 531 can guide a part of the airflow out of the liquid phase tube 5, thereby further reducing the influence of the airflow on the low-temperature medium in the light tube.

[0072] The front end and the rear end of this embodiment refer to the order of arrival at the gas-liquid dividing point.

[0073] Embodiment 3:

[0074] like Figure 1-Figure 6 As shown, this embodiment is based on Embodiment 1; in this embodiment, the heating section 56 includes a first heating tube 561 and a second heating tube 562 arranged in parallel, and a first air guide tube 565 and a second air guide tube 566, and temperature sensors are arranged on the first heating tube 561 and the second heating tube 562;

[0075] One end of the first heating tube 561 and the second heating tube 562 are connected through a first connecting tube 563, and the other end is connected through a second connecting tube 564; the first connecting tube 563 is connected to the sealing section 54, and the second connecting tube 564 is connected to one end of the liquid phase tube 5 close to the inner wall of the outer tank 1 of the low-temperature container;

[0076] A first copper wire 5611 and a second copper wire 5621 are wound around the first heating tube 561 and the second heating tube 562, respectively; a first three-way valve 567 is provided between the first copper wire 5611 and the second connecting tube 564 on the first heating tube 561; a second three-way valve 568 is provided between the second copper wire 5621 and the second connecting tube 564 on the second heating tube 562;

[0077] One end of the first air guide pipe 565 is connected to the first three-way valve 567, and the other end is connected to the second heating pipe 562, and the connection point is located between the second copper wire 5621 and the first connecting pipe 563. The first air guide pipe 565 is provided with a fourth one-way valve 5671;

[0078] One end of the second air guide pipe 566 is connected to the second three-way valve 568, and the other end is connected to the first heating pipe 561, and the connection point is located between the first copper wire 5611 and the first connecting pipe 563. The second air guide pipe 566 is provided with a third one-way valve 5661;

[0079] The third one-way valve 5661, the fourth one-way valve 5671, the first three-way valve 567, the second three-way valve 568, and the temperature sensor are all connected to the controller for communication.

[0080] In a preferred embodiment, a first one-way valve 5612 is provided on the first heating tube 561 between the first three-way valve 567 and the second connecting tube 564 , and a second one-way valve 5622 is provided on the second heating tube 562 between the second three-way valve 568 and the second connecting tube 564 ;

[0081] The first one-way valve 5612 and the second one-way valve 5622 are both in communication with the controller.

[0082] The method of using the liquid level measuring instrument of this embodiment is to heat the low-temperature medium in the heating section 56 by the first copper wire 5611 or the second copper wire 5621 to gasify;

[0083] like Figure 3 As shown, when the second copper wire 5621 is working, the controller controls the second three-way valve 568 to connect the second heating pipe 562 with the second connecting pipe 564, and the controller controls the fourth one-way valve 5671 to open and controls the first three-way valve 567 to connect the first air guide pipe 565 with the first heating pipe 561;

[0084] like Figure 4 As shown, when the first copper wire 5611 is working, the controller controls the first three-way valve 567 to connect the first air pipe 565 with the second connecting pipe 564, and the controller controls the third one-way valve 5661 to open and controls the second three-way valve 568 to connect the second air pipe 566 with the second heating pipe 562.

[0085] The temperature sensor collects the temperature of the first heating tube 561 and the second heating tube 562 in real time and transmits it to the controller, and the controller controls the first copper wire 5611 or the second copper wire 5621 to work.

[0086] This embodiment improves the existing heating section 56 and adopts two parallel heating routes, which can avoid the problem that the low-temperature medium in the liquid phase tube 5 cannot be gasified when the heating copper wire cannot work. At the same time, this embodiment can switch between the two parallel heating routes through automatic control through the structural design of the heating section 56.

[0087] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0088] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and the like cited in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of the relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

Claims

1. A liquid level measuring instrument for a cryogenic container, comprising a gas phase tube (4), a liquid phase tube (5) and a liquid level gauge (6); characterized in that: The portion of the liquid phase tube (5) extending into the low-temperature container comprises: A straight pipe section (51) is arranged in the inner tank (3) of the low-temperature container; the straight pipe section (51) comprises an open section with a first exhaust hole (512) and a bare pipe section without an open hole, and the end of the bare pipe section is a closed end; A drainage tube (52) is arranged at the top of the light pipe section on a side close to the opening section, and the drainage tube (52) is connected to the light pipe section; A flow guide member (57) is disposed in the flow guide tube (52), the width of the flow guide member (57) gradually increasing from bottom to top, and a flow guide cavity (58) is formed between the flow guide member (57) and the flow guide tube (52); A sealing section (54) is provided on the side wall of the inner tank (3); one end of the sealing section (54) is connected to the opening section; A U-shaped air-sealing section (55) is arranged in the vacuum interlayer (2) of the low-temperature container, one end of the U-shaped air-sealing section (55) is connected to the other end of the sealing section (54), and the other end is connected to the heating section (56).

2. A liquid level measuring instrument for a cryogenic container according to claim 1, characterized in that: Also includes: A spiral section (53) is arranged in the inner tank (3); one end of the spiral section (53) is connected to the opening section, and the other end is connected to the sealing section (54); the liquid level of the spiral section (53) is the same as the liquid level of the straight pipe section (51), and a plurality of second exhaust holes (531) are arranged on the spiral section (53).

3. A liquid level measuring instrument for a cryogenic container according to claim 2, characterized in that: The spiral segment (53) comprises a straight segment and an arc segment used to connect the straight segment, and the second exhaust holes (531) on the arc segment are arranged in the radial direction.

4. A liquid level measuring instrument for a cryogenic container according to claim 2, characterized in that: The diameter of the second exhaust hole (531) tends to gradually increase from the inside to the outside.

5. A liquid level measuring instrument for a cryogenic container according to claim 1, characterized in that: A strip-shaped through groove (511) is provided on the top of the optical tube segment, and the drainage tube (52) is connected to the optical tube segment via the strip-shaped through groove (511); the drainage tube (52) and the strip-shaped through groove (511) have the same length, and the length of the drainage tube (52) is greater than the inner diameter of the optical tube segment.

6. A liquid level measuring instrument for a cryogenic container according to claim 1, characterized in that: There is a distance between the bottom of the flow guide (57) and the top of the light tube segment; the outlet end of the flow guide tube (52) is a trumpet-shaped structure; and the diameter of the first exhaust hole (512) tends to gradually increase from the inside to the outside.

7. A liquid level measuring instrument for a cryogenic container according to claim 1, characterized in that: The heating section (56) comprises a first heating tube (561) and a second heating tube (562) arranged in parallel, as well as a first air guide tube (565) and a second air guide tube (566), wherein the first heating tube (561) and the second heating tube (562) are both provided with temperature sensors; One end of the first heating tube (561) and the second heating tube (562) are connected via a first connecting tube (563), and the other end is connected via a second connecting tube (564); the first connecting tube (563) is connected to the sealing section (54), and the second connecting tube (564) is connected to one end of the liquid phase tube (5) close to the inner wall of the outer tank (1) of the low-temperature container; A first copper wire (5611) and a second copper wire (5621) are respectively wound around the first heating tube (561) and the second heating tube (562); a first three-way valve (567) is provided between the first copper wire (5611) and the second connecting tube (564) on the first heating tube (561); and a second three-way valve (568) is provided between the second copper wire (5621) and the second connecting tube (564) on the second heating tube (562); One end of the first air guide tube (565) is connected to the first three-way valve (567), and the other end is connected to the second heating tube (562), and the connection point is located between the second copper wire (5621) and the first connecting tube (563), and a fourth one-way valve (5671) is provided on the first air guide tube (565); One end of the second air guide tube (566) is connected to the second three-way valve (568), and the other end is connected to the first heating tube (561), and the connection point is located between the first copper wire (5611) and the first connecting tube (563), and a third one-way valve (5661) is provided on the second air guide tube (566); The third one-way valve (5661), the fourth one-way valve (5671), the first three-way valve (567), the second three-way valve (568), and the temperature sensor are all connected to the controller for communication.

8. A liquid level measuring instrument for a cryogenic container according to claim 7, characterized in that: A first one-way valve (5612) is provided on the first heating tube (561) between the first three-way valve (567) and the second connecting tube (564), and a second one-way valve (5622) is provided on the second heating tube (562) between the second three-way valve (568) and the second connecting tube (564); The first one-way valve (5612) and the second one-way valve (5622) are both communicatively connected to the controller.

9. A liquid level measuring instrument for a cryogenic container according to any one of claims 1 to 8, characterized in that: The liquid level of the sealing section (54) is the same as the liquid level of the straight pipe section (51); the sealing section (54) comprises a horizontal steel pipe (541), an outer wall of the horizontal steel pipe (541) is provided with an annular groove, a buffer sleeve (542) is provided in the annular groove, and an outer wall of the buffer sleeve (542) is provided with an elastic sealing strip (543) that matches the side wall of the inner tank (3).

10. The method for using the liquid level measuring instrument according to claim 7 or 8, characterized in that: The low-temperature medium in the heating section (56) is vaporized by heating with the first copper wire (5611) or the second copper wire (5621); When the second copper wire (5621) is working, the controller controls the second three-way valve (568) to connect the second heating pipe (562) with the second connecting pipe (564), and the controller controls the fourth one-way valve (5671) to open and controls the first three-way valve (567) to connect the first air guide pipe (565) with the first heating pipe (561); When the first copper wire (5611) is working, the controller controls the first three-way valve (567) to connect the first air guide pipe (565) with the second connecting pipe (564), and the controller controls the third one-way valve (5661) to open and controls the second three-way valve (568) to connect the second air guide pipe (566) with the second heating pipe (562); The temperature sensor collects the temperature of the first heating tube (561) and the second heating tube (562) in real time and transmits the temperature to the controller, and the controller controls the first copper wire (5611) or the second copper wire (5621) to operate.

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