Method and device for measuring inclined liquid level by using optical fiber light-induced heating technology

Abstract

The invention discloses a method and device for measuring the inclined liquid level through the optical fiber light-induced heating technology, and belongs to the technical field of liquid level measurement. The device comprises a liquid tank, two mounting blocks are fixedly arranged on one side of the interior of the liquid tank, a fixing sleeve is rotatably mounted on the two mounting blocks, a multi-stage telescopic rod is fixedly arranged in the fixing sleeve, and the multi-stage telescopic rod is fixedly connected with the liquid tank. A thin cylinder is fixedly arranged at the bottom end of the multi-stage telescopic rod, and three measuring optical fibers used for detecting the liquid level are spirally wound around the outer portion of the thin cylinder. According to the invention, the measurement optical fiber utilizes the attenuation characteristic of the optical fiber, when laser is injected, the thermal effect is generated in the optical fiber due to the attenuation characteristic of the optical fiber, when the measurement optical fiber is located in liquid in a liquid tank, the thermal effect difference between the liquid and an air interface can cause the change of the optical fiber characteristic at the liquid level, and the characteristic enables the measurement process to be free of electric signal participation; therefore, the risk of spark or electrostatic discharge caused by electric signals is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid level measurement, and particularly relates to a method and device for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology. Background Art

[0002] In the fields of industrial production and scientific research, liquid level measurement is of great importance. Especially for the liquid level measurement in inclined containers and the liquid level monitoring of low-temperature flammable and explosive liquids, traditional measurement methods have many limitations.

[0003] Conventional liquid level measurement technologies, such as capacitive and resistive liquid level sensors based on electrical principles, have huge safety hazards when facing low-temperature flammable and explosive liquids due to the possible sparks or electrostatic discharges caused by electrical signals. For example, in the storage and transportation scenarios of liquid hydrogen, liquid oxygen, liquid methane, etc., using such measurement devices based on electrical principles may easily lead to serious explosion accidents if not careful, which greatly limits their applications.

[0004] Some traditional technologies in optical liquid level measurement methods, although partially overcoming the safety problems of electrical measurements, are difficult to guarantee the measurement accuracy of inclined liquid levels. Most of them are based on simple light reflection or refraction principles. When the container is tilted, the propagation path of light and the reflection and refraction angles change complexly, making it difficult to accurately reflect the true liquid level and unable to meet the requirements for accurate measurement of inclined liquid levels.

[0005] At the same time, the existing liquid level measurement devices lack flexibility and adaptability in structural design. Many devices are difficult to be adjusted conveniently according to different usage scenarios and container specifications, resulting in the measurement effect being easily interfered by environmental factors in actual applications.

[0006] In view of the above deficiencies of the existing technologies, the present invention provides a method and device for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology to effectively solve the problems such as safety hazards, low measurement accuracy, and poor structural adaptability existing in the existing technologies. Summary of the Invention

[0007] The purpose of the present invention is to provide a method and device for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology to solve the problems raised in the above background art.

[0008] To achieve the above object, the present invention provides the following technical solution: A method and device for measuring the inclined liquid level using the fiber optic photo-thermal heating technology, including a liquid tank. On one side inside the liquid tank, two mounting blocks are fixedly arranged. A fixed sleeve is rotatably mounted on the two mounting blocks. A multi-stage telescopic rod is fixedly arranged inside the fixed sleeve. The bottom end of the multi-stage telescopic rod is fixedly provided with a thin cylinder. Three measuring optical fibers for detecting the liquid level are spirally wound around the outside of the thin cylinder. When detecting the inclined liquid level, the measuring optical fibers will evenly detect multiple liquid level points through the spiral distribution. Utilizing the fact that the attenuation optical fiber will generate a thermal effect when injecting laser, so that the optical fiber signal will still generate a jump at the liquid interface, and based on the fiber optic OFDR technology, the position where the jump occurs is detected; A fiber optic analysis and detection device is fixedly arranged on the liquid tank. A part of the measuring optical fiber extends outside the liquid tank and is connected to the fiber optic analysis and detection device. Inside the fiber optic analysis and detection device, a laser emission module, a signal detection module, a signal processing module, a matrix operation module, a data storage module, a data display module, and a power supply module are respectively arranged; The laser emission module injects laser through the connected measuring optical fiber. The measuring optical fiber transmits the optical signal to the signal detection module. The signal detection module detects the jump signal based on the fiber optic OFDR technology and transmits the signal to the signal processing module. The signal processing module transmits the detection data of the multi-point jump of the measuring optical fiber to the matrix operation module. The matrix operation module performs matrix comprehensive operation through the multi-point optical information of the optical fiber and obtains the actual data of the real inclined liquid level. Finally, the real liquid level data is respectively transmitted to the data storage module and the data display module. The power supply module supplies power to each module to ensure the normal operation of the equipment.

[0009] As a preferred implementation, a driving motor is fixedly installed on one side of the liquid tank. The transmission shaft of the driving motor is connected with a rotating rod. The rotating rod is rotatably arranged through one side of the liquid tank, and one end of it is connected to the rotating part on one side of the fixed sleeve. Driven by the driving motor, the optical fiber at the bottom of the multi-stage telescopic rod is driven to rotate to a certain extent through the rotating rod.

[0010] As a preferred implementation, a protective pipe sleeve for protecting it is sleeved on the non-detection part of the measuring optical fiber.

[0011] As a preferred implementation, floating ring blocks that can float are installed on both sides of the bottom of the multi-stage telescopic rod through connecting frames.

[0012] As a preferred implementation, a protective cover is fixedly arranged at the bottom of the floating ring block. A part of the thin cylinder is located inside the protective cover. The protective cover has a protective effect on the measuring optical fiber on the thin cylinder.

[0013] As a preferred embodiment, a threaded wall groove is provided inside the protective cover to help balance the internal liquid level.

[0014] As a preferred embodiment, a plurality of communication holes connected to the outside are formed through the threaded wall groove, and the side wall of the protective cover can allow external liquid to flow into it through the communication holes.

[0015] The invention discloses a method for measuring inclined liquid level by using optical fiber photo-induced heating technology, comprising the following steps: S1. First, the laser emission module is started to generate a specific laser which is transmitted to the measuring optical fiber through the optical fiber. The thermal effect is generated due to the attenuation characteristics of the optical fiber. When the measuring optical fiber is in the liquid in the liquid tank, a basic signal is provided according to the difference in thermal effect at the liquid level. S2, the signal detection module monitors and measures the optical fiber feedback light signal in real time based on the optical fiber OFDR technology, accurately captures the thermal effect jump signal at the liquid level, and transmits it to the signal processing module through a dedicated line; S3, after receiving the signal, the signal processing module uses advanced algorithms to remove noise interference and extract key characteristic parameters of the liquid level to form raw data; S4, the original data is transmitted to the matrix operation module, which calculates the tilted liquid level data based on the preset algorithm and geometric model, combined with the geometric relationship of the liquid level information detected by the three measuring optical fibers at different positions and angles, and takes the difference in optical fiber positions into account in the calculation; S5. The matrix operation module transmits the liquid level data to the data storage and display module.

[0016] In step S2, the signal detection module based on optical fiber OFDR technology can accurately identify the weak jump signal at the liquid level in real time with high sensitivity and accuracy, and quickly transmit it to the signal processing module via a low-loss anti-interference line.

[0017] In step S4, the geometric relationship of multi-position angle detection information of three measuring optical fibers spirally wound on a thin cylinder is used, and the matrix operation module constructs a matrix, which is combined with the model operation to obtain accurate liquid level data, and the process takes into account the difference in optical fiber position.

[0018] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, the measuring optical fiber utilizes the optical fiber attenuation characteristic and generates a thermal effect when injecting laser light. When the measuring optical fiber is in the liquid in the liquid tank, the difference in the thermal effect at the liquid-air interface changes the characteristics of the optical fiber at the liquid level. The measurement does not require an electrical signal, avoiding the safety risks caused by electrical signals and ensuring the safety of the liquid level measurement of cryogenic flammable and explosive liquids. At the same time, each module in the optical fiber analysis and detection device collaborates closely. The laser emission module injects laser light into the measuring optical fiber, the signal detection module accurately captures the jump signal of the liquid level thermal effect based on the optical fiber OFDR technology, the signal processing module denoises and extracts key parameters, and the matrix operation module accurately calculates based on the detection information and geometric relationships at different positions and angles of the three measuring optical fibers, greatly improving the measurement accuracy of the inclined liquid level and providing a safe, reliable, and accurate solution for industrial and scientific research liquid level measurement.

[0019] In the present invention, when the drive motor operates, it can drive the rotating rod to rotate, and then drive the fixed sleeve to rotate, driving the thin cylinder at the bottom of the multi-stage telescopic rod and the measuring optical fiber spirally wound around it to rotate to a certain extent. This design enables the measuring optical fiber to not only detect the liquid level in the vertical direction but also rotate and detect within a certain angle range. Since the measuring optical fiber is spirally distributed on the thin cylinder, when performing rotational detection, it can evenly detect multiple liquid level points. Through multi-point detection, more-dimensional liquid level information can be obtained. The detection data of these multi-points, combined with the matrix operation and comparison of each point by the matrix operation module in the optical fiber analysis and detection device, can more comprehensively and accurately analyze the actual situation of the inclined liquid level, and then obtain the actual data of the inclined liquid level, which helps to ensure the accuracy of the inclined liquid level detection.

[0020] In the present invention, when the measuring optical fiber on the thin cylinder contacts the liquid surface, the cooperating protective cover will synchronously enter the liquid. The protective cover can directly protect the measuring optical fiber on the thin cylinder, effectively avoiding damage to the measuring optical fiber caused by impurities and mechanical collisions in the liquid, prolonging the service life of the measuring optical fiber, and ensuring the continuous and stable progress of the detection work. At the same time, the protective cover shields and protects the liquid range to be detected around the thin cylinder, reducing the influence of the sudden change of the overall liquid level inclination on the liquid state within this range. When the overall liquid level suddenly changes in inclination, the liquid in the protective cover can maintain a relatively stable state to a certain extent due to its relatively enclosed space structure, thus providing a more stable detection environment for the measuring optical fiber and helping to ensure the accuracy of the liquid level detection.

[0021] In the present invention, the spiral wall grooves formed inside the protective shield facilitate the flow of liquid within the protective shield. When there is liquid inside the protective shield, the liquid can flow and distribute more smoothly along the spiral wall grooves. In combination with the multiple communication holes penetrating through the spiral wall grooves and communicating with the outside, the side wall of the protective shield can allow the external liquid to flow into it, thereby ensuring the overall consistency of the liquid levels inside and outside the protective shield. This enables the liquid environment detected by the measurement optical fiber to be relatively stable.

[0022] In the present invention, the floating ring blocks are installed on both sides of the bottom of the multi-stage telescopic rod, and they can float on the liquid surface. When the liquid level changes, the floating ring blocks will rise or fall accordingly with the rise and fall of the liquid level. At this time, the multi-stage telescopic rod will adaptively expand and contract according to the position change of the floating ring blocks. This adaptive expansion and contraction function ensures that the measurement optical fiber on the thin cylinder can maintain a relatively stable measurement depth. Regardless of whether the liquid level is rising or falling, the measurement optical fiber can always be at an appropriate liquid position for detection, avoiding the measurement optical fiber from getting out of the detection range or having a large change in depth due to large fluctuations in the liquid level, thereby ensuring that the measurement optical fiber can continuously and stably obtain accurate liquid level data. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 is a schematic diagram of the sectional three-dimensional structure of the present invention; Figure 3 is a schematic diagram of the partial three-dimensional structure of the present invention; Figure 4 is a schematic diagram of the partial sectional three-dimensional structure of the present invention; Figure 5 is a schematic diagram of the three-dimensional structure of the measurement optical fiber of the present invention; Figure 6 is a schematic diagram of the sectional three-dimensional structure of the protective shield of the present invention; Figure 7 is a schematic diagram of the rear three-dimensional structure of the present invention; Figure 8 is a schematic diagram of the operation of the optical fiber analysis and detection equipment module of the present invention.

[0024] In the figure: 1, liquid tank; 2, mounting block; 3, fixed sleeve; 4, multi-stage telescopic rod; 5, thin cylinder; 6, measurement optical fiber; 7, optical fiber analysis and detection equipment; 8, drive motor; 9, rotating rod; 10, connecting frame; 11, floating ring block; 12, protective shield; 13, spiral wall groove; 14, communication hole; 15, protective pipe sleeve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following further describes the present invention in conjunction with embodiments.

[0026] The following embodiments are used to illustrate the present invention, but cannot be used to limit the protection scope of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions. Any simple improvement to the method of the present invention under the premise of the concept of the present invention falls within the scope of protection required by the present invention.

[0027] Please refer to Figure 1-8 , the present invention provides a method and device for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology, including a liquid tank 1. On one side inside the liquid tank 1, two mounting blocks 2 are fixedly arranged. A fixed sleeve 3 is rotatably mounted on the two mounting blocks 2. A multi-stage telescopic rod 4 is fixedly arranged inside the fixed sleeve 3. A thin cylinder 5 is fixedly arranged at the bottom end of the multi-stage telescopic rod 4. Three measuring optical fibers 6 for detecting the liquid level are spirally wound around the outside of the thin cylinder 5. When detecting the inclined liquid level, the measuring optical fibers 6 will evenly detect multiple liquid level points through the spiral distribution. Utilizing the fact that the attenuated optical fiber will generate a thermal effect when injecting laser, so that the optical fiber signal will still produce a jump at the liquid interface, and the position where the jump occurs is detected based on the optical fiber OFDR technology; A fiber optic analysis and detection device 7 is fixedly arranged on the liquid tank 1. A part of the measuring optical fiber 6 extends outside the liquid tank 1 and is connected to the fiber optic analysis and detection device 7. Inside the fiber optic analysis and detection device 7, a laser emission module, a signal detection module, a signal processing module, a matrix operation module, a data storage module, a data display module and a power supply module are respectively arranged; The laser emission module is connected to the measurement optical fiber 6 to inject laser light. The measurement optical fiber 6 transmits the optical signal to the signal detection module. The signal detection module detects the jump signal based on the fiber optic OFDR technology and transmits the signal to the signal processing module. The signal processing module transmits the detection data of the multi-point jump of the measurement optical fiber to the matrix operation module. The matrix operation module performs matrix comprehensive operations through the multi-point optical information of the optical fiber and obtains the actual data of the inclined liquid level. Finally, the real liquid level data is transmitted to the data storage module and the data display module respectively. The power supply module supplies power to each module to ensure the normal operation of the equipment. The measurement optical fiber 6 utilizes the attenuation characteristics of the optical fiber. When injecting laser light, due to the attenuation characteristics of the optical fiber, a thermal effect is generated in the optical fiber. When the measurement optical fiber 6 is in the liquid in the liquid tank 1, the difference in the thermal effect at the liquid-air interface will cause a change in the characteristics of the optical fiber at the liquid level. This characteristic enables the measurement process to be carried out without the participation of electrical signals, thereby avoiding the risk of sparks or electrostatic discharge caused by electrical signals and ensuring safety during the measurement of the liquid level of low-temperature flammable and explosive liquids. At the same time, the laser emission module, signal detection module, signal processing module, matrix operation module, etc. in the optical fiber analysis and detection device 7 cooperate closely. The laser emission module injects laser light into the measurement optical fiber 6. The signal detection module, based on the fiber optic OFDR technology, can accurately capture the jump signal generated by the thermal effect at the liquid level. The signal processing module removes noise interference and extracts key characteristic parameters. The matrix operation module performs precise calculations based on the liquid level information detected by the three measurement optical fibers 6 at different positions and angles on the thin cylinder 5 and specific geometric relationships, thereby greatly improving the measurement accuracy of the inclined liquid level and providing a safe, reliable and accurate solution for the liquid level measurement in the industrial production and scientific research fields. The working principle of the matrix operation module is relatively complex. Since the three measurement optical fibers in the device are helically wound around the thin cylinder, they can detect the liquid level information from different positions and angles. For example, in an actual measurement scenario, when the liquid level is inclined, the degree of influence of the thermal effect at the liquid-air interface on the surfaces of the measurement optical fibers at different positions is different, and the intensity and change trend of the optical signals they feedback also vary. There are specific geometric relationships between these difference information. The matrix operation module needs to process them according to the preset algorithm and geometric model. Assume that the three measurement optical fibers are A, B, and C respectively, and their position coordinates on the thin cylinder are , and the change value of the optical signal intensity related to the liquid level detected is . The matrix operation module first constructs a 3x3 matrix M, and its elements are determined according to the position relationship of the measurement optical fibers and the preset geometric model, such as: Among them, The value is related to the relative position and angle of the measurement optical fiber, and is determined in advance through a large number of experiments and theoretical calculations. Then, a column vector V is constructed: Calculate the liquid level data L through matrix multiplication: During the operation process, fully consider the influence of the position difference of different measurement optical fibers on the data. For example, adjust the matrix elements according to factors such as the spacing and winding angle of the measurement optical fibers, so as to achieve accurate calculation of the liquid level data of the inclined liquid.

[0028] Such as Figure 2 and Figure 3 As shown, a driving motor 8 is fixedly installed on one side of the liquid tank 1. The conveying shaft of the driving motor 8 is connected with a rotating rod 9. The rotating rod 9 penetrates and is rotatably arranged on one side of the liquid tank 1, and one end of it is connected with the rotating part on one side of the fixed sleeve 3. Driven by the driving motor 8, the optical fiber at the bottom of the multi-stage telescopic rod 4 is driven to rotate to a certain extent through the rotating rod 9. When the driving motor 8 operates, it can drive the rotating rod 9 to rotate, and then make the fixed sleeve 3 rotate, driving the thin cylinder 5 at the bottom of the multi-stage telescopic rod 4 and the measurement optical fiber 6 spirally wound thereon to rotate to a certain extent. This design enables the measurement optical fiber 6 to not only detect the liquid level in the vertical direction, but also rotate and detect within a certain angle range. Since the measurement optical fiber 6 is spirally distributed on the thin cylinder 5, when performing rotational detection, it can evenly detect multiple liquid level points. Through the detection of multiple points, more-dimensional liquid level information can be obtained. The detection data of these multiple points, combined with the matrix operation module in the optical fiber analysis and detection device 7 for matrix operation and comparison of each point, can more comprehensively and accurately analyze the actual situation of the inclined liquid level, and then obtain the actual data of the inclined liquid level, which helps to ensure the accuracy of the detection of the inclined liquid level.

[0029] Such as Figure 3 As shown, a protective pipe sleeve 15 for protecting it is sleeved on the non-detection part of the measurement optical fiber 6.

[0030] Such as Figure 3 As shown, floating ring blocks 11 that can float are installed on both sides of the bottom of the multi-stage telescopic rod 4 through connecting frames 10. The floating ring blocks 11 are installed on both sides of the bottom of the multi-stage telescopic rod 4, and they can float on the liquid surface. When the liquid level changes, the floating ring blocks 11 will rise or fall accordingly with the rise and fall of the liquid level. At this time, the multi-stage telescopic rod 4 will perform adaptive telescoping according to the position change of the floating ring blocks 11. This adaptive telescoping function ensures that the measurement optical fiber 6 on the thin cylinder 5 can maintain a relatively stable measurement depth. Whether the liquid level is in the rising or falling state, the measurement optical fiber 6 can always be in a suitable liquid position for detection, avoiding the measurement optical fiber 6 getting out of the detection range or the depth changing greatly due to large fluctuations in the liquid level, thus ensuring that the measurement optical fiber 6 can continuously and stably obtain accurate liquid level data.

[0031] Such asFigure 3 As shown in the figure, a protective shield 12 is fixedly arranged at the bottom of the floating ring block 11. A part of the thin cylinder 5 is located inside the protective shield 12. The protective shield 12 has a protective effect on the measuring optical fiber 6 on the thin cylinder 5. When the measuring optical fiber 6 on the thin cylinder 5 contacts the liquid level, the matching protective shield 12 will synchronously enter the liquid. The protective shield 12 can directly protect the measuring optical fiber 6 on the thin cylinder 5, effectively avoiding damage to the measuring optical fiber 6 caused by factors such as impurities and mechanical collisions in the liquid, prolonging the service life of the measuring optical fiber 6, and ensuring the continuous and stable progress of the detection work. At the same time, the protective shield 12 shields and protects the liquid range around the thin cylinder 5 that needs to be detected, reducing the influence of the sudden change of the overall liquid level tilt on the liquid state within this range. When the overall liquid level suddenly changes, the liquid inside the protective shield 12 can maintain a relatively stable state to a certain extent due to its relatively enclosed space structure, thereby providing a more stable detection environment for the measuring optical fiber 6 and helping to ensure the accuracy of the liquid level detection.

[0032] As Figure 6 shown in the figure, a threaded wall groove 13 for assisting the liquid level balance inside it is opened inside the protective shield 12.

[0033] As Figure 6 shown in the figure, a plurality of communication holes 14 communicating with the outside are penetrated and opened in the threaded wall groove 13. The side wall of the protective shield 12 can allow the liquid outside to flow into it through the communication holes 14. The threaded wall groove 13 opened inside the protective shield 12 facilitates the flow of the liquid inside the protective shield 12. When there is liquid inside the protective shield 12, the liquid can flow and distribute more smoothly along the threaded wall groove 13. Then, in cooperation with the plurality of communication holes 14 penetrating through the threaded wall groove 13 and communicating with the outside, the side wall of the protective shield 12 can allow the liquid outside to flow into it, thereby ensuring the overall consistency of the liquid level inside and outside the protective shield 12, making the liquid environment detected by the measuring optical fiber 6 relatively stable.

[0034] The present invention discloses a method for measuring the inclined liquid level by using the fiber optic photo-thermal heating technology, including the following steps: S1. First, the laser emission module is started to generate specific laser light, which is transmitted to the measuring optical fiber 6 through the optical fiber. Due to the attenuation characteristics of the optical fiber, a thermal effect is generated. When the measuring optical fiber 6 is in the liquid in the liquid tank 1, a basic signal is provided according to the difference in the thermal effect at the liquid level. S2. The signal detection module monitors the feedback optical signal of the measuring optical fiber 6 in real time based on the fiber optic OFDR technology, accurately captures the thermal effect jump signal at the liquid level, and transmits it to the signal processing module through a dedicated line. S3. After receiving the signal, the signal processing module uses an advanced algorithm to remove noise interference and extract the key characteristic parameters of the liquid level to form the original data. S4. The raw data is transmitted to the matrix operation module, which calculates the inclined liquid level data based on the geometric relationship of the liquid level information detected at different positions and angles by three measurement optical fibers 6 according to a preset algorithm and geometric model. The position difference of the optical fibers is considered during the operation. S5. The matrix operation module transmits the liquid level data to the data storage and display module.

[0035] In step S2, relying on high sensitivity and accuracy, the signal detection module based on the optical fiber OFDR technology accurately identifies the weak jump signal at the liquid level in real time and quickly transmits it to the signal processing module through a low-loss anti-interference line.

[0036] In step S4, using the geometric relationship of the multi-position angle detection information of three measurement optical fibers 6 helically wound around the thin cylinder 5, the matrix operation module constructs a matrix and combines the model operation to obtain accurate liquid level data. The position difference of the optical fibers is considered during the process.

[0037] The working principle and usage process of the present invention are as follows: First, the laser emission module is started to generate a laser with a specific power and wavelength, which is transmitted to the measurement optical fiber 6 through an optical fiber. When the laser is transmitted in the measurement optical fiber 6, due to the attenuation characteristic of the optical fiber, a thermal effect is generated in the optical fiber. When the measurement optical fiber 6 is in the liquid in the liquid tank 1, the difference in the thermal effect at the liquid-air interface will cause the characteristics of the optical fiber at the liquid level to change, providing a basic signal for subsequent measurement. Then, based on the optical fiber OFDR technology, the signal detection module monitors the signal fed back by the measurement optical fiber 6 in real time. The jump signal generated by the thermal effect at the liquid level is accurately captured by the signal detection module, and then the signal is quickly and stably transmitted to the signal processing module through a dedicated data transmission line. After receiving the signal, the signal processing module processes it using an advanced signal processing algorithm. First, the noise and interference components in the signal are removed to improve the signal-to-noise ratio and quality of the signal. Then, the key characteristic parameters related to the liquid level are extracted to form the raw data. Next, the raw data is transmitted to the matrix operation module, which calculates the data according to a preset algorithm and geometric model to accurately calculate the liquid level data of the inclined liquid. Finally, the matrix operation module transmits the calculated liquid level data to the data storage module and the data display module respectively.

[0038] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An apparatus for measuring an inclined liquid level using the optical fiber photo-thermal heating technology, comprising a liquid tank (1), characterized in that: On one side inside the liquid tank (1), two mounting blocks (2) are fixedly arranged. A fixing sleeve (3) is rotatably mounted on the two mounting blocks (2). A multi-stage telescopic rod (4) is fixedly arranged inside the fixing sleeve (3). A thin cylinder (5) is fixedly arranged at the bottom end of the multi-stage telescopic rod (4). Three measuring optical fibers (6) for detecting the liquid level are spirally wound around the outside of the thin cylinder (5). When detecting the inclined liquid level, the measuring optical fibers (6) can evenly detect multiple liquid level points through the spiral distribution. Utilizing the fact that the attenuation optical fiber will generate a thermal effect when injecting laser, the optical fiber signal will still generate a jump at the liquid interface, and the position where the jump occurs is detected based on the optical fiber OFDR technology; An optical fiber analysis and detection device (7) is fixedly arranged on the liquid tank (1). A part of the measuring optical fiber (6) extends outside the liquid tank (1) and is connected to the optical fiber analysis and detection device (7). Inside the optical fiber analysis and detection device (7), a laser emission module, a signal detection module, a signal processing module, a matrix operation module, a data storage module, a data display module, and a power supply module are respectively arranged; The laser emission module injects laser through the measuring optical fiber (6). The measuring optical fiber (6) transmits the optical signal to the signal detection module. The signal detection module detects the jump signal based on the optical fiber OFDR technology and transmits the signal to the signal processing module. The signal processing module transmits the detection data of the multi-point jump of the measuring optical fiber to the matrix operation module. The matrix operation module performs matrix comprehensive operation through the multi-point optical information of the optical fiber and obtains the actual data of the real inclined liquid level. Finally, the real liquid level data is respectively transmitted to the data storage module and the data display module. The power supply module supplies power to each module to ensure the normal operation of the device.

2. The device for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology according to claim 1, wherein: A driving motor (8) is fixedly installed on one side of the liquid tank (1). The transmission shaft of the driving motor (8) is connected to a rotating rod (9). The rotating rod (9) penetrates and is rotatably arranged on one side of the liquid tank (1), and one end of it is connected to the rotating part on one side of the fixing sleeve (3). Driven by the driving motor (8), the optical fiber at the bottom of the multi-stage telescopic rod (4) is driven to rotate to a certain extent through the rotating rod (9).

3. The device for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology according to claim 1, wherein: A protective tube sleeve (15) for protecting it is sleeved on the non-detection part of the measuring optical fiber (6).

4. The device for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology according to claim 1, characterized in that: On both sides at the bottom of the multi-stage telescopic rod (4), floating ring blocks (11) that can float are installed through connecting frames (10).

5. The device for measuring the inclined liquid level by using the fiber optic photo-thermal heating technology according to claim 4, characterized in that: A protective cover (12) is fixedly arranged at the bottom of the floating ring block (11). A part of the thin cylinder (5) is located inside the protective cover (12). The protective cover (12) has a protective effect on the measuring optical fiber (6) on the thin cylinder (5).

6. The device for measuring the inclined liquid level by using the fiber optic photo-thermal heating technology according to claim 5, characterized in that: Thread-shaped wall grooves (13) for assisting the liquid level balance inside it are opened inside the protective cover (12).

7. A device for measuring the inclined liquid level by using the fiber optic photo-thermal heating technology according to claim 6, characterized in that: A plurality of communication holes (14) communicating with the outside are penetrated through the thread-shaped wall grooves (13). The side wall of the protective cover (12) can allow the external liquid to flow into it through the communication holes (14).

8. A method for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology, characterized in that: Including the following steps: S1. First, the laser emission module is activated to generate specific laser light, which is transmitted through an optical fiber to the measurement optical fiber (6). Due to the attenuation characteristics of the optical fiber, a thermal effect is generated. When the measurement optical fiber (6) is in the liquid in the liquid tank (1), a basic signal is provided according to the difference in thermal effects at the liquid level. S2. The signal detection module, based on the optical fiber OFDR technology, monitors the feedback optical signal of the measurement optical fiber (6) in real time, accurately captures the thermal effect jump signal at the liquid level, and transmits it to the signal processing module through a dedicated line. S3. After receiving the signal, the signal processing module uses advanced algorithms to remove noise interference and extract the key characteristic parameters of the liquid level to form the original data. S4. The original data is transmitted to the matrix operation module, which, according to the preset algorithm and geometric model, combines the geometric relationships of the liquid level information detected at different positions and angles of the three measurement optical fibers (6) to calculate the inclined liquid level data, taking into account the differences in the positions of the optical fibers during the calculation. S5. The matrix operation module transmits the liquid level data to the data storage and display module.

9. A method for measuring the inclined liquid level by using the fiber optic photo-thermal heating technology according to claim 8, characterized in that: In step S2, the signal detection module based on the optical fiber OFDR technology, relying on high sensitivity and accuracy, can accurately identify the weak jump signal at the liquid level in real time and quickly transmit it to the signal processing module through a low-loss anti-interference line.

10. A method for measuring the inclined liquid level by using the optical fiber photo-thermal heating technology according to claim 8, characterized in that: In step S4, the information detected at multiple positions and angles by the three measurement optical fibers (6) wound around the thin cylinder (5) in a spiral manner is utilized.

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