Liquid level measuring tool and liquid nitrogen storage container

Abstract

The application relates to the technical field of liquid level position measurement, and particularly provides a liquid level measurement tool and a liquid nitrogen storage container, which are aimed at solving the problems of low liquid nitrogen liquid level measurement precision and poor reliability in the prior art, thereby affecting the accuracy of test results. Therefore, the liquid level measurement tool comprises a mounting seat, a measurement pipe arranged on the mounting seat, and a float rod with opposite first and second ends, wherein the first end is inserted into the measurement pipe, the second end penetrates through the mounting seat and extends out of the measurement pipe and is used for contacting a liquid to be measured, and the float rod can move along the axial direction of the measurement pipe when the liquid level of the liquid to be measured changes. The liquid level measurement tool provided by the application can convert the liquid level change in the container which is difficult to directly observe into clear and intuitive mechanical displacement through the cooperation of the float rod and the measurement pipe, effectively solves the inconvenience of measurement caused by the problem of blocked view in the traditional measurement mode, and realizes convenient and accurate monitoring of the liquid level.

Description

Technical Field

[0001] This application relates to the field of liquid level measurement technology, specifically providing a liquid level measuring tool and a liquid nitrogen storage container. Background Technology

[0002] The test results of high-precision specific surface area and pore size analyzers are heavily dependent on the stable low-temperature environment of the sample tube. Practice has shown that even minute fluctuations in the liquid level within the liquid nitrogen cup can cause changes in the temperature distribution of the sample tube, directly contributing to poor repeatability and low accuracy of the test data. Therefore, accurate measurement and control of the liquid level is crucial. However, the easy vaporization of liquid nitrogen and the small-diameter design of the liquid nitrogen cup pose challenges to the intuitive and accurate measurement of the liquid level.

[0003] In related technologies, liquid nitrogen measurement commonly employs the direct measuring ruler method and the fixed-size tool observation method. The direct measuring ruler method involves inserting the ruler into the container and judging the liquid level based on the residual mark on the ruler's surface. However, the ruler is prone to bending, and the mark sublimates rapidly, leading to large reading errors. The fixed-size tool observation method requires repeated insertion of rigid measuring tools of different specifications, which is cumbersome and easily disturbs the liquid surface. These technologies generally face common problems such as insufficient measurement accuracy, cumbersome operation procedures, and limited measurement range adjustment. Furthermore, the incompatibility defects between metal materials and glass inner liner pose safety hazards and cannot meet the stringent requirements of high-precision specific surface area and pore size analyzers. There is an urgent need to develop new measurement technologies that combine safety, convenience, and accuracy.

[0004] Therefore, a new technical solution is needed in this field to solve the above problems. Utility Model Content

[0005] This application aims to solve the aforementioned technical problem, namely, the low accuracy and poor reliability of liquid nitrogen level measurement in the prior art, which affects the accuracy of test results.

[0006] In a first aspect, this application provides a liquid level measuring tool, comprising:

[0007] Mounting base;

[0008] A measuring tube is mounted on the mounting base;

[0009] A float has a first end and a second end, the first end of which extends into the measuring tube and the second end passes through the mounting base and extends out of the measuring tube for contact with the liquid to be measured. When the liquid level of the liquid to be measured changes, the float can move axially along the measuring tube.

[0010] By adopting the above technical solution, the liquid level measuring tool provided in this application transforms the liquid level changes in the container, which are difficult to observe directly, into clear and intuitive mechanical displacement by observing the position changes of the float in the measuring tube. This effectively solves the inconvenience of measurement caused by obstructed vision and large subjective judgment errors in traditional measurement methods, and realizes convenient and accurate monitoring of liquid level.

[0011] In one technical solution of the above-mentioned liquid level measuring tool, the liquid level measuring tool further includes:

[0012] A buoy is attached to the second end of the float.

[0013] With the above technical solution, the float significantly increases the contact area of ​​the float tip in the liquid. This not only enhances the float's sensitivity to changes in liquid level, but also effectively suppresses irregular swaying of the float caused by slight fluctuations in the liquid surface by providing more significant and balanced buoyancy, thereby improving the stability of the measurement.

[0014] In one technical solution of the above-mentioned liquid level measuring tool, the mounting base is provided with a guide channel, the guide channel is connected to the cavity of the measuring tube, and the float is slidably engaged with the guide channel.

[0015] By adopting the above technical solution, the straightness and stability of the float during axial movement are enhanced, effectively preventing radial deviation or jamming during movement, and ensuring accurate and smooth transmission of liquid level changes.

[0016] In one technical solution of the above-mentioned liquid level measuring tool, a limiting part is provided at the first end, which is used to prevent the first end of the float from detaching from the measuring tube.

[0017] When the above technical solution is adopted, the limiting part effectively prevents the float from coming out of the measuring tube during axial movement by mechanical limiting, thereby avoiding functional failure or tool damage that may be caused by the float coming out.

[0018] In one technical solution of the above-mentioned liquid level measuring tool, the mounting base is provided with an annular groove, and the measuring tube is inserted into the annular groove.

[0019] When the above technical solution is adopted, this plug-in mating method not only simplifies the assembly process and completes the initial fixation of the measuring tube and the mounting base without complicated connectors, but also ensures the coaxiality between the measuring tube and the mounting base through the circumferential constraint of the annular groove, avoiding radial displacement of the measuring tube during use, thereby ensuring the stability of the float moving in the cavity.

[0020] In one technical solution of the above-mentioned liquid level measuring tool, the measuring tube includes an inner tube and an outer tube sleeved outside the inner tube, and the float is located inside the inner tube;

[0021] The inner tube is marked with graduations.

[0022] By adopting the above technical solution, the scale markings are set on the inner tube, and the outer tube can effectively protect the inner tube from external dust, splashing liquid, and other factors that could contaminate the scale markings. This ensures that operators can still clearly read the scale values ​​during long-term use, and solves the problem of easy contamination of traditional single-tube scales.

[0023] In one technical solution of the above-mentioned liquid level measuring tool, the liquid level measuring tool further includes:

[0024] The first electrode is disposed on the measuring tube;

[0025] The second electrode is disposed on the float;

[0026] A signal generator is electrically connected to the first electrode and the second electrode respectively. When the float moves to a preset position, the second electrode contacts the first electrode, thereby triggering the signal generator.

[0027] By employing the above technical solution, this design converts the mechanical displacement of the float into a defined electrical signal. When the liquid level reaches a preset position, the electrode contact automatically triggers the signal generator, thereby realizing the transformation from passive manual reading to proactive intelligent early warning, greatly improving the automation, reliability, and operational efficiency of liquid level monitoring.

[0028] In one technical solution of the above-mentioned liquid level measuring tool, the position of the first electrode can be adjusted along the axial direction of the measuring tube.

[0029] With the above technical solution, the adjustable position of the first electrode fundamentally improves the tool's versatility and efficiency. When the preset liquid level to be monitored changes, no parts need to be replaced; simply adjusting the electrode height is sufficient to reset the alarm threshold, thus enhancing the device's versatility.

[0030] In a second aspect, this application provides a liquid nitrogen storage container, comprising:

[0031] The container body has an opening;

[0032] The liquid level measuring tool as described in any one of the first aspects, wherein the mounting base is disposed at the opening.

[0033] With the above technical solution, the liquid nitrogen storage container provided in this application, by assembling the above liquid level measuring tool, allows the float and float ball to directly extend into the inner cavity to contact the liquid nitrogen, transforming the difficult-to-observe liquid level changes in the container into intuitive readings, thus solving the pain points of inconvenient and large error in traditional liquid nitrogen storage container liquid level monitoring.

[0034] In one technical solution of the above-mentioned liquid nitrogen storage container, the liquid nitrogen storage container further includes:

[0035] A magnetic ring is positioned near the opening;

[0036] The mounting base is provided with a magnetic suction component, which cooperates with the magnetic ring.

[0037] With the above technical solution, the magnetic attraction structure enables quick assembly and disassembly of measuring tools and storage containers. Furthermore, the magnetic ring structure allows the mounting base to be fixed at any angle in the circumference, and the operator can flexibly adjust the tool direction according to the on-site operating space or the best reading angle without realigning, which greatly improves the adaptability and convenience of use. Attached Figure Description

[0038] The preferred embodiments of this application are described below with reference to the accompanying drawings, in which:

[0039] Figure 1 This is a schematic diagram of the structure of a liquid nitrogen storage container according to an embodiment of this application;

[0040] Figure 2 yes Figure 1 A cross-sectional view of a liquid nitrogen storage container;

[0041] Figure 3 This is a cross-sectional structural schematic diagram of a liquid level measuring tool according to an embodiment of this application;

[0042] Figure 4 This is a schematic diagram of the structure of a mounting base according to an embodiment of this application;

[0043] Figure 5 This is a partial structural schematic diagram of a liquid level measuring tool according to another embodiment of this application, intended to illustrate the structural schematic diagram of an electrical detection component;

[0044] Figure 6 This is a partial structural schematic diagram of a liquid nitrogen storage container according to this application, intended to illustrate the structure at the opening of the liquid nitrogen storage container. List of reference numerals in the attached diagram:

[0045] 1-Liquid level measuring tool, 11-Mounting base, 110-Guide channel, 111-Annular groove, 112-Guide cylinder, 113-Connecting plate, 12-Measuring tube, 121-Inner tube, 122-Outer tube, 13-Float rod, 131-Limiting part, 14-Float ball, 15-First magnetic suction component, 16-Second magnetic suction component;

[0046] 2-Liquid nitrogen storage container, 21-Container body, 22-Magnetic ring;

[0047] 30-Battery compartment, 31-Metal conductor, 32-Electrode spring, 33-Battery, 34-Indicator light. Detailed Implementation

[0048] Preferred embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0049] It should be noted that in the description of this application, terms such as "upper," "lower," "left," "right," "inner," and "outer," which indicate direction or positional relationship, are based on the direction or positional relationship shown in the accompanying drawings. These terms are used merely for ease of description and do not indicate or imply that the relevant device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, ordinal numbers such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0051] Please refer to Figure 1 and Figure 2 It shows a schematic diagram of a liquid level measuring tool 1 applied to a container according to an embodiment of this application. Figure 1 The assembly state of the liquid level measuring tool 1 and the container as a whole is shown. Figure 2 The sectional view further illustrates the internal structure and relative position of the liquid level measuring tool 1 and the container.

[0052] refer to Figure 3This is a half-sectional structural diagram of a liquid level measuring tool 1 according to an embodiment of this application. The liquid level measuring tool 1 includes a mounting base 11, a measuring tube 12, and a float 13. The mounting base 11 serves as a basic fixing unit for mounting the entire tool at the opening of a container. The measuring tube 12 is fixedly mounted on the mounting base 11, and its tube wall is provided with scale markings for reading. The interior of the tube forms a channel for the float 13 to move. The first end of the float 13 extends into the interior of the measuring tube 12, and the second end passes through the mounting base 11 and extends out of the measuring tube 12. The end of the second end of the float 13 is used to contact the liquid to be measured. When the liquid level changes, the float 13 can move axially along the measuring tube 12 under the action of buoyancy, realizing the dynamic transmission of liquid level changes.

[0053] The liquid level measuring tool 1 provided in this application converts the difficult-to-observe changes in liquid level within a container into a clear and intuitive mechanical displacement of the top of the float 13 within the measuring tube 12. When the liquid level in the container rises or falls, the buoyancy exerted by the liquid on the second end of the float 13 changes accordingly, thereby driving the float 13 to move axially within the measuring tube 12. In this way, the operator can obtain an accurate liquid level reading by directly reading the corresponding position of the top of the float 13 on the scale markings of the measuring tube 12.

[0054] In one embodiment, the liquid level measuring tool 1 further includes a float 14, which is fixedly connected to the second end of the float rod 13. Specifically, the float 14 and the float rod 13 can be connected by means of threads or snap-fit, ensuring that liquid level changes can be transmitted synchronously and accurately even under liquid fluctuations. Compared to a structure where only the end of the float rod 13 contacts the liquid, the float 14 increases the contact area with the liquid, improves the sensitivity and stability of buoyancy sensing, and avoids irregular shaking of the float rod 13 due to liquid surface fluctuations. This ensures that the position of the top of the float rod 13 on the scale markings of the measuring tube 12 is more accurate, providing operators with more reliable liquid level readings and further optimizing measurement accuracy and device practicality.

[0055] In one embodiment, the mounting base 11 is provided with a guide channel 110, which is coaxially connected to the cavity of the measuring tube 12 and together forms a continuous sliding path. The float 13 passes through the guide channel 110 and forms a sliding engagement with it. This structure enhances the straightness and stability of the float 13 during axial movement, effectively preventing radial offset or jamming during movement, and ensuring accurate and smooth transmission of liquid level changes.

[0056] Furthermore, a limiting part 131 is provided at the first end of the float 13. This limiting part 131 serves to axially limit the movement of the first end of the float 13, preventing it from detaching from the measuring tube 12 during movement and thus causing the entire float 13 to come off. In this embodiment, the limiting part 131 is specifically a cap, which is placed on the first end of the float 13. When the float 13 moves downward to its limit position due to a drop in liquid level, the cap will abut against the end face of the mounting base 11, thereby preventing the float 13 from continuing to detach from the measuring tube 12. At the same time, the cap also has the function of assisting in reading. As a clear marker at the top of the float 13, it allows the operator to more clearly observe the movement position of the float 13, thus enabling quick and accurate reading of the liquid level value corresponding to the top of the float 13 on the scale marking of the measuring tube 12.

[0057] In one embodiment, in conjunction with reference to Figure 4 , Figure 4 This is a schematic diagram of the mounting base 11. To ensure a stable assembly between the measuring tube 12 and the mounting base 11, an annular groove 111 is provided on the mounting base 11. One end of the measuring tube 12 is directly inserted into this annular groove 111. The annular groove 111 is annularly recessed along the axial direction of the mounting base 11, and one end of the measuring tube 12 is directly inserted into the annular groove 111 and fits tightly against the groove wall. A guide channel 110 on the mounting base 11 extends axially through the center area of ​​the bottom of the annular groove 111, allowing the guide channel 110 to communicate with the cavity of the measuring tube 12. This insertion and mating method not only simplifies the assembly process, eliminating the need for complex connectors to complete the initial fixation of the measuring tube 12 and the mounting base 11, but more importantly, it ensures the coaxiality between the measuring tube 12 and the mounting base 11 through the circumferential constraint of the annular groove 111, preventing radial displacement of the measuring tube 12 during use, thereby ensuring the stability of the float 13 moving within the cavity.

[0058] In one embodiment, the measuring tube 12 adopts a double-layer tube structure, including an inner tube 121 and an outer tube 122 sleeved outside the inner tube 121, with the float 13 located inside the inner tube 121. Specifically, during assembly, the inner tube 121 is attached to the inner wall of the annular groove 111 of the mounting base 11, and the outer tube 122 is attached to the outer wall of the annular groove 111. The tight fit between the double-layer tube walls and the annular groove 111 further enhances the installation stability of the measuring tube 12. Simultaneously, the scale markings are set on the inner tube 121, and the outer tube 122 effectively protects the inner tube 121 from external dust, splashes of the liquid being measured, and other factors that could contaminate the scale markings. This ensures that operators can still clearly read the scale values ​​during long-term use, solving the problem of easy contamination of the scale markings in traditional single-tube systems.

[0059] In one embodiment, a guide cylinder 112 is provided on the side of the mounting base 11 opposite to the measuring tube 12. The inner cavity of the guide cylinder 112 forms an extended channel coaxially connected with the internal guide channel 110 of the mounting base 11. This structure not only ensures that the float 13 can continue to move smoothly in a straight line after passing through the mounting base 11, playing a secondary guiding and protective role, but also allows the guide cylinder 112 itself to be designed to partially extend into the container opening. By adapting and cooperating with the inner wall of the container, it enhances the stability of the connection between the mounting base 11 and the container, preventing the measuring tool from shaking or shifting during use.

[0060] Specifically, refer to Figure 4 The mounting base 11 includes a main body and a connecting plate 113. The connecting plate 113 is connected between the main body and the guide cylinder 112. The connecting plate 113 extends outward along the circumference of the main body. When the guide cylinder 112 is inserted into the container, the connecting plate 113 can be placed on the open end face of the container and is stably connected to the container by magnetic connection or snap-fit ​​connection, providing a solid installation foundation for the accurate operation of the entire measuring tool.

[0061] In one embodiment, the liquid level measuring tool 1 further integrates an electrical detection component for fixed-point monitoring or alarm of the liquid level. Specifically, the electrical detection component includes a first electrode, a second electrode, and a signal generator, which together constitute a triggering and prompting mechanism for a preset liquid level position. The first electrode is fixedly mounted on the measuring tube 12, its installation position corresponding to the preset liquid level height of the liquid to be measured. The second electrode is mounted on a float 13, moving synchronously along the axial direction of the measuring tube 12 with the float 13, and maintaining a suitable positional correspondence with the first electrode. The signal generator is electrically connected to the first and second electrodes via wires, forming a complete conductive circuit. Its working principle is as follows: when a change in the liquid level in the container causes the float 13 to move to the preset position, the second electrode on the float 13 will contact the first electrode on the measuring tube 12, making the conductive circuit open, thereby triggering the signal generator to issue a prompt signal, realizing automatic monitoring and early warning of a specific liquid level.

[0062] Specifically, the form of the signal generator can be flexibly selected according to actual usage requirements. For example, in one specific embodiment, the signal generator is an audible and visual signal generator. When the electrode contacts the conductive circuit, its internal buzzer emits a continuous or intermittent prompt sound, while the indicator light (such as an LED) illuminates or flashes. Through dual audible and visual cues, the operator can quickly perceive that the liquid level has reached the preset position in complex working environments. In a specific implementation, refer to... Figure 5 , Figure 5The figure shows a schematic diagram of the integrated electrical detection component of the liquid level measuring tool 1. In this embodiment, an indicator light 34 is used as the visual prompting element for the signal generator. A battery compartment 30 is provided at the top of the measuring tube 12, powered by a built-in battery 33. A metal conductor 31 is provided at the top of the float 13 as the second electrode, while an electrode spring 32, serving as the first electrode, is installed on the measuring tube 12 at the position corresponding to the preset liquid level. The indicator light 34 is connected in series with the battery 33, the electrode spring 32, and the metal conductor 31 to form an open circuit system. When the liquid level changes and the float 13 moves to the preset position, the metal conductor 31 at its top contacts the electrode spring 32, thereby conducting the circuit and triggering the indicator light 34 to light up, achieving a visual liquid level alarm.

[0063] In another specific embodiment, the signal generator can be a wireless signal generator, which integrates a Bluetooth or Wi-Fi module. Upon triggering, it sends a wireless signal to a associated control terminal (such as a computer or mobile app) to achieve remote liquid level monitoring, suitable for highly automated testing scenarios. These signal generator types can all effectively cooperate with the electrode triggering structure, improving the intelligence and convenience of liquid level measurement.

[0064] Furthermore, to enhance the flexibility and adaptability of liquid level monitoring, the position of the first electrode can be adjusted along the axial direction of the measuring tube 12. This can be achieved through various structural designs: for example, a strip-shaped adjustment groove can be formed along the axial direction on the outer wall of the measuring tube 12. The first electrode slides into the adjustment groove via bolts. Loosening the bolts allows the electrode to move up and down along the groove, and after adjusting to the scale corresponding to the target liquid level, the bolts can be tightened to secure it. Alternatively, multiple threaded holes can be provided axially distributed on the measuring tube 12. The first electrode engages with different threaded holes via a threaded connector to achieve discrete position adjustment. An elastic clamp structure can also be used, where the first electrode is fixed to the clamp. Loosening the clamp's locking mechanism allows it to slide along the axial direction of the measuring tube 12, and re-locking it after it reaches the desired position.

[0065] This adjustable design allows the liquid level measuring tool 1 to adapt to different testing needs and container specifications. When the preset liquid level of the liquid to be tested changes, such as when changing to a liquid nitrogen cup of different volumes, or when adjusting the liquid level corresponding to the optimal temperature zone required for sample testing, it is not necessary to replace the entire measuring tube 12 or electrode assembly. The trigger point can be reset to the new preset liquid level simply by adjusting the axial position of the first electrode, thus improving the versatility of the device.

[0066] This application also provides a liquid nitrogen storage container 2, which mainly includes a container body 21 and a liquid level measuring tool 1 as described above. The container body 21, as the core component for liquid nitrogen storage, has an opening at its top for adding liquid nitrogen and installing equipment. The liquid level measuring tool 1 is mounted to this opening via its mounting base 11. After assembly, the float 13 and float ball 14 of the liquid level measuring tool 1 extend into the inner cavity of the container body 21 and contact the liquid nitrogen, enabling monitoring of the liquid nitrogen level. This allows the liquid nitrogen storage container 2 to combine storage functionality with precise liquid level measurement capabilities.

[0067] In one embodiment, in conjunction with reference to Figure 6 , Figure 6 The figure shows a cross-sectional view of the opening of the liquid nitrogen storage container 2. An annular groove is provided on the lid of the liquid nitrogen storage container 2, and a magnetic ring 22 is embedded within the groove. Correspondingly, a magnetic suction element is embedded in the connecting plate 113 of the mounting base 11 of the liquid level measuring tool 1. The magnetic suction element and the magnetic ring 22 form a magnetic attraction structure. Compared to traditional bolt connections, the magnetic attraction method allows for tool-free installation and removal, improving operational convenience and facilitating subsequent maintenance and replacement of the liquid level measuring tool 1. Furthermore, the annular structure of the magnetic ring allows the mounting base 11 to be fixed arbitrarily along its circumference. Operators can flexibly adjust the circumferential angle of the liquid level measuring tool 1 at the container opening according to the required operating space and reading angle, without the need for realignment or disassembly and reinstallation.

[0068] In this embodiment, although a magnetic ring is described as the preferred embodiment, the implementation of magnetic attraction is not limited to this. To further improve the versatility of the liquid level measuring tool 1 and adapt to liquid nitrogen storage containers 2 with different structures, magnetic attraction components such as magnetic attracting sheets can be used instead of the magnetic ring 22 and directly attached to the mouth of the liquid nitrogen storage container 2. Such magnetic attraction components can also form a stable magnetic attraction with the magnetic attraction components on the mounting base 11 of the liquid level measuring tool 1, which not only continues the convenience of quick installation and removal without tools, but also retains the advantage of flexible adjustment of the circumferential angle. At the same time, it breaks the dependence on the annular groove structure at the container opening, allowing the measuring tool to be adapted to more liquid nitrogen storage containers without a preset installation structure.

[0069] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A liquid level measuring tool (1), characterized in that, include: Mounting bracket (11); Measuring tube (12), which is disposed on the mounting base (11); A float (13) has a first end and a second end, the first end of which extends into the measuring tube (12), and the second end passes through the mounting base (11) and extends out of the measuring tube (12) for contacting the liquid to be measured. When the liquid level of the liquid to be measured changes, the float (13) can move along the axial direction of the measuring tube (12). A float (14) is connected to the second end of the float (13). A guide channel (110) is provided on the mounting base (11). The guide channel (110) is connected to the cavity of the measuring tube (12). The float (13) is slidably engaged with the guide channel (110).

2. The liquid level measuring tool (1) according to claim 1, characterized in that, The first end is provided with a limiting part (131), which is used to prevent the first end of the float (13) from detaching from the measuring tube (12).

3. The liquid level measuring tool (1) according to claim 1, characterized in that, The mounting base (11) is provided with an annular groove (111), and the measuring tube (12) is inserted into the annular groove (111).

4. The liquid level measuring tool (1) according to claim 3, characterized in that, The measuring tube (12) includes an inner tube (121) and an outer tube (122) sleeved outside the inner tube (121), and the float (13) is located inside the inner tube (121); The inner tube (121) is provided with scale markings.

5. The liquid level measuring tool (1) according to any one of claims 1 to 4, characterized in that, The liquid level measuring tool (1) also includes: The first electrode is disposed on the measuring tube (12); The second electrode is disposed on the float (13); A signal generator is electrically connected to the first electrode and the second electrode respectively. When the float (13) moves to a preset position, the second electrode contacts the first electrode, thereby triggering the signal generator.

6. The liquid level measuring tool (1) according to claim 5, characterized in that, The position of the first electrode can be adjusted along the axial direction of the measuring tube (12).

7. A liquid nitrogen storage container (2), characterized in that, include: The container body (21) has an opening; The liquid level measuring tool (1) as described in any one of claims 1 to 6, wherein the mounting base (11) is disposed at the opening.

8. The liquid nitrogen storage container (2) according to claim 7, characterized in that, The liquid nitrogen storage container (2) also includes: A magnetic ring (22) is disposed near the opening; The mounting base (11) is provided with a magnetic suction element, which cooperates with the magnetic ring.

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