CN113465696B - Method and system for measuring liquid level of melt in container - Google Patents

Abstract

A method and system for measuring the level of a melt in a vessel. The measuring method comprises the following steps: determining a first distance between an observation point and a first point on the bottom surface of the heating chamber, wherein the observation point has a first visual angle direction in which the first point is observed through the light-transmitting hole and a second visual angle direction in which a second point on the liquid surface of the melt in the container is observed through the light-transmitting hole, and the first point and the second point are distributed along the vertical direction; determining a first angle corresponding to the first visual angle direction and a second angle corresponding to the second visual angle direction according to the calibration device; determining the liquid level according to the first distance, the first angle, and the second angle. The measuring method and the system can simply and effectively measure the liquid level of the melt in the container.

Description

Method and system for measuring liquid level of melt in container

technical field

The present application relates to the technical field of containers, in particular to a method and system for measuring the liquid level of a melt in a container.

Background technique

The liquid level gauge in the related art can be used to measure the liquid level of some containers, but the application of the liquid level gauge in the related art is very limited. Measurement.

The cold crucible glass solidification technology has the characteristics of high working temperature, wide processing range, long service life, uniform melt, small equipment size, and easy decommissioning. Cold crucible vitrification technology can not only be used for low and medium level radioactive wastes such as solid wastes, resins, and concentrates produced by nuclear power plants; Therefore, the research progress of this technology has received extensive attention. In the operation of nuclear power, a large amount of radioactive waste is bound to be produced. Among them, the reprocessing of spent fuel and the high-level radioactive waste liquid produced by it has the characteristics of high specific activity, high heat release rate, and contains some nuclides with long half-life and high biological toxicity. and one of the key issues for the sustainable development of the nuclear fuel cycle industry. As a new nuclear waste treatment technology, cold crucible vitrification technology has its unique advantages in the treatment of nuclear power waste and high-level radioactive waste liquid.

The cold crucible is a circular or elliptical container composed of several arc-shaped blocks or tubes. Cooling water is passed into the arc-shaped blocks or tubes to maintain the cold wall. The gaps between the arc-shaped blocks or tubes are filled with insulating substances, and the The internal material is heated, and there is a water-cooled coil made of copper tube outside the cold crucible. Since the cold crucible adopts a water-cooled structure, a solid glass shell layer will be formed in the area with low temperature near the cooling pipe, which avoids the corrosion of the cold crucible by the molten material. The cold crucible glass solidification system mainly includes: cold crucible, feeding subsystem, glass discharging subsystem, flue gas purification subsystem and instrument control system. There are three main forms of cold crucible vitrification process, namely: two-step vitrification process, one-step vitrification process and one-step incineration vitrification process. The two-step vitrification process is that the waste liquid is first calcined in a calcining furnace and then mixed with the glass base material and sent to a cold crucible; the one-step vitrification process is that the waste liquid and the glass base material are directly sent to the cold crucible; one-step incineration In the vitrification process, combustible solid waste is mixed with glass base material and sent to a cold crucible. The first two processes are mainly used to treat waste liquid, and the latter process is mainly used to treat solid waste.

According to the different ways of use, electromagnetic cold crucibles can be divided into two types: batch type and continuous casting type, but the basic principle is the same, mainly composed of water-cooled crucible, power supply and other auxiliary facilities. A spiral induction coil is wound around the crucible, and the induction coil is connected with a power source to generate an alternating electromagnetic field. When an alternating current is passed through the coil, an alternating electromagnetic field is generated in and around the coil. Since each metal tube of the cold crucible is insulated from each other, an induced current is generated in each tube. When the instantaneous current of the induction coil is counterclockwise, a clockwise induced current is simultaneously generated in the cross-section of each tube, and the current directions on the cross-sections of two adjacent tubes are opposite. The direction is the same, and the outward shows a magnetic field enhancement effect. Therefore, each gap of the cold crucible is a strong magnetic field. The cold crucible is like a strong current device, which gathers the magnetic lines of force on the materials in the crucible, and the materials in the crucible are cut by the magnetic lines of the alternating magnetic field. According to the electromagnetic field theory, an induced electromotive force is generated in the material in the crucible. Due to the existence of the induced electromotive force, a closed current loop will be formed in the thin layer of the melt surface of the material. The cold crucible uses the eddy current to heat the material.

The cold crucible can heat the material into a melt. During the operation of the cold crucible, the measurement of the liquid level of the melt has a great influence on the operation state of the cold crucible. At the same time, for some special fields, such as vitrification of radioactive waste, corresponding measuring equipment is required to reduce the contact with radioactive substances and avoid the escape of radioactive substances. However, the related art cannot effectively measure the liquid level of the melt in the cold crucible.

SUMMARY OF THE INVENTION

According to a first aspect of the present application, a method for measuring the liquid level of a melt in a container is provided, the container defines a heating chamber, the container is provided with a light-transmitting hole, and a scale device is provided in the heating chamber , the method includes: determining a first distance between an observation point and a first point on the bottom surface of the heating cavity, the observation point having a first viewing angle direction from which the first point is observed through the light-transmitting hole, and The second viewing angle direction of the second point on the liquid surface of the melt in the container is observed through the light-transmitting hole, and the first point and the second point are distributed along the vertical direction; determined according to the scale device The first angle corresponding to the first viewing angle direction and the second angle corresponding to the second viewing angle direction; the liquid level is determined according to the first distance, the first angle and the second angle.

Optionally, determining the first angle corresponding to the first viewing angle direction according to the calibration device includes: determining a height difference between the calibration device and the observation point; determining that the observation point is along the first viewing angle direction The horizontal distance between the first projection point on the scale device and the observation point; the first angle is determined according to the horizontal distance and the height difference.

Optionally, determining the second angle corresponding to the second viewing angle direction according to the calibration device includes: determining a second projection point of the observation point on the calibration device along the second viewing angle direction, and, the second distance between the first projection points; the second angle is determined according to the second distance, the horizontal distance and the height difference.

Optionally, the container includes: a cavity defining the heating cavity, the heating cavity having an opening; a cover for opening and closing the opening, and the cover is provided with the light-transmitting hole.

Optionally, the cavity body includes: a bottom wall; at least one side wall, the at least one side wall extending upward from a periphery of the bottom wall to form the heating cavity; the first point and the first point Both points are located on the side wall.

Optionally, the scale device is a scale ruler or a light tape ruler with a known length of each color block.

Optionally, the determining the liquid level according to the first distance, the first angle and the second angle includes: determining the liquid level according to the following formula:

In the formula, L1 is the first distance, β is the second angle, α is the first angle, and Y is the liquid level.

Optionally, the scale device closes the light-transmitting hole.

According to a second aspect of the present application, there is provided a liquid level measurement system of a melt in a container, comprising: the container, which defines a heating chamber, the container is provided with a light-transmitting hole, and the heating A scale device is arranged in the cavity; the scale device is used to determine a first angle corresponding to the first viewing angle direction and a second angle corresponding to the second viewing angle direction, and the first angle and the second angle are used to match the first angle The liquid level is determined jointly by the distance, the first distance is the distance between the observation point and the first point on the bottom surface of the heating chamber, and the observation point has the first point from which the first point is observed through the light-transmitting hole. A viewing angle direction, and a second viewing angle direction in which a second point on the liquid surface of the melt in the container is observed through the light-transmitting hole, and the first point and the second point are distributed in a vertical direction.

Optionally, the first angle is determined by a horizontal distance and a height difference, the height difference is the height difference between the scale device and the observation point, and the horizontal distance is the distance between the first projection point and the observation point. The first projection point is the projection point of the observation point on the scale device along the first viewing angle direction.

Optionally, the second angle is determined by the second distance, the horizontal distance and the height difference, the second distance is the distance between the second projection point and the first projection point, the The second projection point is the projection point of the observation point on the scale device along the second viewing angle direction.

Optionally, the container includes: a cavity defining the heating cavity, the heating cavity having an opening; a cover for opening and closing the opening, and the cover is provided with the light-transmitting hole.

Optionally, the cavity body includes: a bottom wall; at least one side wall, the at least one side wall extending upward from a periphery of the bottom wall to form the heating cavity; the first point and the first point Both points are located on the side wall.

Optionally, the scale device is a scale ruler or a light tape ruler with a known length of each color block.

Optionally, the measurement system further includes a processor configured to determine the liquid level according to the following formula:

In the formula, L1 is the first distance, β is the second angle, α is the first angle, and Y is the liquid level.

Optionally, the scale device closes the light-transmitting hole.

Description of drawings

Other objects and advantages of the present application will be apparent from the following description of the present application with reference to the accompanying drawings, and may assist in a comprehensive understanding of the present application.

1 is a schematic structural diagram of a container according to an embodiment of the present application;

2 is an application schematic diagram of a method for measuring the liquid level of a melt in a container according to an embodiment of the present application;

3 is an application schematic diagram of a method for measuring the liquid level of a melt in a container according to another embodiment of the present application;

Fig. 4 is a schematic enlarged view of area A in Fig. 3;

Fig. 5 is a schematic enlarged view of region B in Fig. 3;

FIG. 6 is a schematic structural diagram of an optical tape ruler of a container according to an embodiment of the present application.

It should be noted that the accompanying drawings are not necessarily drawn to scale, but are only shown in a schematic manner that does not affect the reader's understanding.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiment is one embodiment of the present application, but not all embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

Unless otherwise defined, technical or scientific terms used in this application shall have the ordinary meaning as understood by those of ordinary skill in the art to which this application belongs.

Embodiments of the present application first provide a method for measuring the liquid level of a melt in a container 10 , where the container 10 defines a heating chamber 110 . 1 is a schematic structural diagram of a container 10 according to an embodiment of the present application; FIG. 2 is an application schematic diagram of a method for measuring the liquid level of a melt in the container 10 according to an embodiment of the present application; FIG. 3 is another embodiment of the present application. The application schematic diagram of the method for measuring the liquid level of the melt in the container 10 of the example; FIG. 4 is a schematic enlarged view of the area A in FIG. 3 ; FIG. 5 is a schematic enlarged view of the area B in FIG. 3 .

It can be understood that the container 10 can be a cold crucible. The cold crucible uses a power supply to generate a high-frequency current, and then converts it into an electromagnetic current through an induction coil (which can be a high-frequency induction coil) and penetrates into the material to be heated to form an eddy current to generate heat and realize the material. direct heating and melting. The cavity of the cold crucible is a container composed of metal arc-shaped blocks or tubes that pass through the cooling water. The shape of the container is mainly circular or oval. When the cold crucible is working, the cooling water is continuously passed through the metal tube, and the temperature of the melt in the cold crucible is higher than that of the cold crucible. High temperature, but the wall surface of the cavity still maintains a relatively low temperature (generally less than 200 ° C), so that the material forms a low temperature area on the inner wall surface during operation to form a solid shell. The cold crucible does not need refractory materials and does not need to be heated by electrodes. The formed solid shell can reduce the corrosive effect of materials on the cold crucible, prolong the service life of the cold crucible, and enable the cold crucible to process corrosive materials. The feed port may be located at the bottom of the heating chamber 110 .

When the cold crucible is working, an alternating current is passed through the induction coil, and an alternating electromagnetic field is generated in and around the induction coil. Since each metal tube of the cold crucible is insulated from each other, an induced current is generated in each tube, and the current directions on the cross-sections of two adjacent tubes are opposite, and the magnetic fields established between the tubes are in the same direction, and outwardly appear as magnetic fields Enhancement effect. Therefore, each gap of the cold crucible is a strong magnetic field. The cold crucible is like a strong current device, which gathers the magnetic lines of force on the materials in the cold crucible, and the materials in the cold crucible are cut by the magnetic lines of the alternating magnetic field. An induced electromotive force is generated in the material in the cold crucible. Due to the existence of the induced electromotive force, a closed current loop will be formed in the thin layer of the melt surface of the material, and the material will be melted due to the large amount of heat generated by the eddy current loop.

Among them, the cold crucible can be used in the two-step vitrification process. In the two-step vitrification process, the radioactive material to be treated is first pretreated in a rotary calciner, and converted from a liquid state to a slurry or solid powder state, and then the pretreated material is pretreated in a rotary calciner. The processed materials are added to the cold crucible together with the glass base material, and are melted into glass in the cold crucible, thereby avoiding the harm of radioactive substances to the environment.

The liquid level of the melt in the container 10 directly affects the operation state of the container 10. For example, when the liquid level is too low, it is easy to waste heating resources, and when the liquid level is too high, it is easy to reduce the heating effect, resulting in relatively Multi-melt solidification, difficult to discharge. When the container 10 is a cold crucible, the low liquid level will also cause the melt to deviate from the main power area of the induction coil, resulting in a decrease in the utilization rate of energy by the cold crucible, and a decrease in the melt temperature, the melting speed, and the melting activity. , When the liquid level in the cold crucible is too low, it is easy for the melt to be unable to utilize the magnetic field energy, which makes the cold crucible "crash" and can only be restarted after recharging after cooling. When the liquid level in the cold crucible is too high, the high-temperature melting area is far away from the bottom of the cold crucible, resulting in a low temperature at the bottom of the melt, making it extremely difficult to unload, and even making it impossible to discharge. Therefore, the cold crucible needs to monitor the liquid level in the crucible in real time during operation, and keep the liquid level within a suitable height range. Even if the cold crucible maintains a high melting activity, the hot area cannot be too far away from the bottom of the crucible to affect the Unloading of cold crucibles.

Due to the special high temperature environment in the heating chamber 110 of the container 10, and the materials processed by the container 10 may be radioactive and corrosive materials, it is difficult to install some liquid level detection devices in the heating chamber 110 to measure the liquid level. However, the measurement method provided in the embodiment of the present application can be applied to the container 10 .

The container 10 is provided with a light-transmitting hole 210 , and the heating chamber 110 is provided with a scale device 300 . In some embodiments, the scale device 300 can be a scale, so that this kind of scale device 300 is easy to implement. In other embodiments, the scale device 300 can be a light tape ruler with a known length of each color block.

6 is a schematic structural diagram of a light-tape ruler of a container according to an embodiment of the present application. There is no specific scale on the ruler of the light-tape ruler, and the ruler body has transparent bands of at least two colors. Taking a 3-color light-tape ruler as an example, for example It can have multiple areas arranged in sequence, and each area has color blocks of red, yellow and blue arranged in sequence (in Figure 6, r represents the red color block, y represents the yellow color block, and b represents the blue color block) , the length of each color block is known. For example, the length of the i-th color block is li. Under the premise of knowing the length of each color block, the corresponding distance can be determined by using the color block, which can be used to match the scale. Similar to the function of the ruler, it can also be used to determine the liquid level. It is understood that each color block can be of unequal size and length; and multiple color ribbons can be combined together to obtain the furnace liquid level more accurately. For example, each color block of the first ribbon is 1cm, and each color block of the second ribbon is 3mm. The combined reading of the two can be more accurate. The specific color configuration, combination manner, and length selection can be determined according to the actual situation, which is not limited in this embodiment of the present application.

The method includes: determining a first distance L1 between an observation point 20 and a first point 30 on the bottom surface of the heating cavity 110 , where the observation point 20 has a distance between the observation point 20 and the first point 30 observed through the light-transmitting hole 210 . The first viewing angle direction, and the second viewing angle direction of the second point 40 on the liquid surface of the melt in the container 10 observed through the light-transmitting hole 210 , the first point 30 and the second point 40 are along the distribution in the vertical direction; the first angle corresponding to the first viewing angle direction is determined according to the scale device 300 (which can be represented by the angle α between the first viewing angle direction and the vertical direction, and in other embodiments, it can also be represented by the included angle between the first viewing angle direction and the horizontal direction, etc.) and the second angle corresponding to the second viewing angle direction (which can be represented by the included angle β between the second viewing angle direction and the vertical direction, in other implementations In an example, it can also be represented by the included angle between the second viewing angle direction and the horizontal direction, etc.); the liquid level is determined according to the first distance L1, the first angle and the second angle.

At this time, the liquid level

Understandably, it is sometimes difficult to directly obtain the included angle α and the included angle β, and the values of the included angle α and the included angle β can be obtained according to other methods. For example, the distance L2 from point 30 or point 40 to L1 can be determined; according to the scale device 300, determine the shadow point 50 and shadow point 60 of the included angle α and the included angle β on the scale device 300, and the distance of the L1 The distances are respectively S1 and S2; the height difference between S1 or S2 and the observation point is H1. Then tanα=L2/L1, or tanα=S1/H1, tanβ=S2/H1.

It can be understood that there are various methods for solving the included angle α and the included angle β, which are not limited in the embodiments of the present application.

It is understandable that the manner of determining the position of each projection point on the scale device 300 may be determined by various manners, such as a camera, a laser, or even a user's visual estimation, which is not limited in this embodiment of the present application.

The container 10 may include a cavity 100 and a cover 200, the cavity 100 defines the heating cavity 110, and the heating cavity 110 has an opening 111; the cover 200 is used to open and close the opening 111, and the cover The light-transmitting hole 210 is opened in 200 . The container 10 has a simple structure and can ensure the heating effect.

The cavity 100 may include a bottom wall 120 and at least one side wall 130 . The at least one side wall 130 extends upward from the periphery of the bottom wall 120 to form the heating chamber 110 ; the first point 30 and the second point 40 are both located on the side wall 130 for easy observation and determine the relevant data.

The scale device 300 can also close the light-transmitting hole. Specifically, the scale device 300 can be installed on the light-transmitting hole in the form of a quartz scale sheet, etc., which can prevent the leakage of exhaust gas and reduce the installation difficulty of the scale device 300. , and at the same time, it is convenient to replace and clean the scale device 300 and so on.

The embodiment of the present application also provides a system for measuring the liquid level of the melt in the container 10 , and the measurement system includes the container 10 .

The container 10 defines a heating cavity 110, the container 10 is provided with a light-transmitting hole 210, and a scale device 300 is arranged in the heating cavity 110; the scale device 300 is used to determine the first angle corresponding to the first viewing angle direction and the second angle corresponding to the second viewing angle direction, the first angle and the second angle are used to determine the liquid level together with the first distance, and the first distance is the observation point 20 and the heating chamber 110 The distance between the first points 30 on the bottom surface, the observation point 20 has a first viewing angle direction from which the first point 30 is observed through the light-transmitting hole 210 , and the container is observed through the light-transmitting hole 210 In the second viewing angle direction of the second point 40 on the liquid surface of the melt in 10, the first point 30 and the second point 40 are distributed along the vertical direction.

In some embodiments, the first angle is determined by a horizontal distance and a height difference, the height difference being the height difference between the scale device 300 and the observation point 20 , and the horizontal distance being the first projection point 50 and the observation point 20 . The horizontal distance between the observation points 20, and the first projection point 50 is the projection point of the observation point 20 on the scale device 300 along the first viewing angle direction.

In some embodiments, the second angle is determined by the second distance, the horizontal distance and the height difference, and the second distance is the distance between the second projection point 60 and the first projection point 50 distance, the second projection point 60 is the projection point of the observation point 20 on the scale device 300 along the second viewing angle direction.

In some embodiments, the container 10 includes: a cavity 100 defining the heating cavity 110, the heating cavity 110 having an opening 111; a cover 200 for opening and closing the opening 111, the cover The light-transmitting hole 210 is opened in 200 .

In some embodiments, the cavity 100 includes: a bottom wall 120; at least one side wall 130, the at least one side wall 130 extends upward from the periphery of the bottom wall 120 to form the heating cavity 110; The first point 30 and the second point 40 are both located on the side wall 130 .

In some embodiments, the scale device 300 is a scale or a light-tape scale with a known length of each color block.

In some embodiments, the measurement system further includes a processor configured to determine the liquid level according to the following formula:

In the formula, L1 is the first distance, β is the second angle, α is the first angle, and Y is the liquid level.

In some embodiments, the scale device 300 closes the light-transmitting hole.

For the container 10 of the measurement system and the specific measurement process provided in the embodiments of the present application, reference may be made to the foregoing embodiments, and details are not repeated here. The measurement system provided by the embodiment of the present application can simply and effectively measure the liquid level of the melt in the container 10, which improves user experience, and the measurement system provided by the embodiment of the present application can be used in the container 10. Measure at runtime.

For the embodiments of the present application, it should also be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments may be combined with each other to obtain new embodiments.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application should be subject to the protection scope of the claims.

Claims (14)

1. A method of measuring a level of a melt in a container (10), the container (10) defining a heating chamber (110), the container (10) defining a light-transmissive aperture (210), a scale device (300) disposed in the heating chamber (110), the method comprising:

determining a first distance between a viewing point (20) and a first point (30) on the bottom surface of the heating chamber (110), the viewing point (20) having a first viewing direction in which the first point (30) is viewed through the light-transmissive aperture (210) and a second viewing direction in which a second point (40) on the level of the melt in the container (10) is viewed through the light-transmissive aperture (210), the first point (30) and the second point (40) being vertically spaced;

determining a first angle corresponding to the first visual angle direction and a second angle corresponding to the second visual angle direction according to the calibration device (300);

determining the liquid level according to the first distance, the first angle and the second angle;

wherein determining a first angle corresponding to the first viewing angle direction according to the scale device (300) comprises:

determining a height difference between the scale device (300) and the observation point (20);

determining a horizontal distance between the observation point (20) and a first projection point (50) of the observation point (20) on the scale device (300) along the first visual angle direction;

determining the first angle according to the horizontal distance and the height difference.

2. The measurement method according to claim 1, wherein determining a second angle corresponding to the second viewing angle direction from the scale device (300) comprises:

determining a second distance between a second projection point (60) of the observation point (20) on the scale device (300) along the second view angle direction and the first projection point (50);

determining the second angle according to the second distance, the horizontal distance, and the height difference.

3. The measuring method according to claim 1, wherein the container (10) comprises:

a cavity (100) defining the heating cavity (110), the heating cavity (110) having an opening (111);

and a cover (200) for opening and closing the opening (111), wherein the cover (200) is provided with the light-transmitting hole (210).

4. The measurement method according to claim 3, wherein the cavity (100) comprises:

a bottom wall (120);

at least one side wall (130), the at least one side wall (130) extending upwardly from a perimeter of the bottom wall (120) to form the heating cavity (110);

the first point (30) and the second point (40) are both located at the side wall (130).

5. The measurement method according to claim 1,

the scale device (300) is a scale or an optical tape scale with known color block length.

6. The measurement method of claim 1, wherein said determining the liquid level from the first distance, the first angle, and the second angle comprises:

determining the liquid level according to the following formula:

wherein L1 is the first distance, β is the second angle, α is the first angle, and Y is the liquid level.

7. The measurement method according to claim 1,

the scale device (300) closes the light hole.

8. A system for measuring a level of a melt in a vessel (10), comprising:

the container (10) defines a heating cavity (110), the container (10) is provided with a light transmission hole (210), and a scale device (300) is arranged in the heating cavity (110);

the calibration device (300) is used for determining a first angle corresponding to a first visual angle direction and a second angle corresponding to a second visual angle direction, the first angle and the second angle are used for determining the liquid level together with a first distance, the first distance is a distance between a viewing point (20) and a first point (30) on the bottom surface of the heating cavity (110), the viewing point (20) has a first visual angle direction for observing the first point (30) through the light transmission hole (210) and a second visual angle direction for observing a second point (40) on the liquid surface of the melt in the container (10) through the light transmission hole (210), and the first point (30) and the second point (40) are distributed along the vertical direction;

the first angle is determined by a horizontal distance and a height difference, the height difference is a height difference between the scale device (300) and the observation point (20), the horizontal distance is a horizontal distance between a first projection point (50) and the observation point (20), and the first projection point (50) is a projection point of the observation point (20) on the scale device (300) along the first view angle direction.

9. The measurement system of claim 8,

the second angle is determined by a second distance, the horizontal distance and the height difference, the second distance is a distance between a second projection point (60) and the first projection point (50), and the second projection point (60) is a projection point of the observation point (20) on the scale device (300) along the second view angle direction.

10. The measuring system according to claim 8, wherein the container (10) comprises:

a cavity (100) defining the heating cavity (110), the heating cavity (110) having an opening (111);

and a cover (200) for opening and closing the opening (111), wherein the cover (200) is provided with the light-transmitting hole (210).

11. The measurement system according to claim 10, wherein the cavity (100) comprises:

a bottom wall (120);

at least one side wall (130), the at least one side wall (130) extending upwardly from a periphery of the bottom wall (120) to form the heating cavity (110);

the first point (30) and the second point (40) are both located at the side wall (130).

12. The measurement system of claim 8,

the scale device (300) is a scale or an optical tape scale with known color block length.

13. The measurement system of claim 8, further comprising:

a processor configured to determine the liquid level according to the following formula:

wherein L1 is the first distance, β is the second angle, α is the first angle, and Y is the liquid level.

14. The measurement system of claim 8,

the scale device (300) closes the light hole.

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