A liquid level gauge calibration device and calibration method

Abstract

This invention relates to the field of level gauge calibration technology, and mainly discloses a level gauge calibration device and method, including a steel frame and a water pump body. The steel frame is equipped with an upper water tank, a middle water tank, and a lower water tank, with a reference level gauge mounted on the middle water tank. This invention utilizes a three-stage water tank structure (upper, middle, and lower tanks) to inject water into the middle water tank via gravity flow from the upper tank, effectively avoiding the liquid level fluctuation problem caused by direct pump injection. Then, through coordinated control of the liquid levels in the upper and lower tanks, a stable rise and fall of the liquid level in the middle water tank is achieved. Finally, through synchronous data acquisition and computer comparison between the reference level gauge and the ultrasonic level gauge under test, automatic detection of multiple liquid levels across the entire range is realized. The system's automatic reset function supports continuous testing of batch instruments, significantly improving detection efficiency and consistency.

Description

Technical Field

[0001] This invention relates to the field of level gauge calibration, and more particularly to a level gauge calibration device and calibration method. Background Technology

[0002] Ultrasonic level gauges are widely used in level monitoring in industries such as water conservancy, environmental protection, chemical, petroleum, and power due to their advantages of non-contact measurement, easy installation, and wide applicability. The performance of ultrasonic level gauges directly affects production safety, measurement accuracy, and process control quality; therefore, regular testing and calibration before or during use are of significant engineering importance.

[0003] Currently, the testing and calibration of ultrasonic level gauges mainly rely on the following methods: manual comparison, using a ruler to manually measure the height of the liquid level and comparing it with the reading of the ultrasonic level gauge; or using a handheld calibrator: using a portable calibrator for comparison testing on site; or using automated level gauge testing: usually using a single water tank and a water pump to directly inject water to generate liquid level changes.

[0004] However, the above methods have limited accuracy: direct water pump injection generates liquid level fluctuations and bubbles, which interfere with ultrasonic signals and affect measurement accuracy. When using manual methods, there are many manual operation steps, and the testing time for a single instrument is long, making it difficult to meet the needs of batch testing. Moreover, it is difficult to keep the liquid level sequence, stabilization time, and other conditions consistent when different instruments are tested, which affects the fairness and comparability of the comparison results. In addition, after changing instruments, the system needs to be manually reset and refilled with water, which is cumbersome and has poor data correlation, making it difficult to support the batch testing of large-scale instruments. Summary of the Invention

[0005] The technical problem this invention aims to solve is: to improve the accuracy of liquid level calibration, this invention provides a liquid level gauge calibration device and calibration method, comprising: a steel frame for supporting installation and a water pump body for pumping water. The steel frame is divided into upper, middle, and lower sections. The upper section houses an upper water tank for storing water to be tested. The middle section houses a middle water tank equipped with a reference level gauge for calibrating the water level inside the middle tank. The lower section houses a lower water tank for storing water flowing down from the middle tank. The reference level gauge is a pulse-type level gauge with a measurement accuracy of ±0.5mm and a resolution of 0.1mm, serving as a standard reference for the entire testing process. The reference level gauge and each level gauge under test are electrically connected to a computer. During the testing process, all level gauges collect level signals in real time and transmit them to the computer. The intermediate water tank is equipped with a flow guide plate and a defoaming plate to reduce the impact of the water flow and eliminate large foam generated in the water. The intermediate water tank is equipped with a heating jacket, which is electrically connected to an external temperature controller to simulate the liquid level detection environment under different temperature conditions.

[0006] More specifically, the input end of the water pump body is connected to the lower water tank via a flexible hose, and the output end of the water pump body is connected to the upper water tank via a first pipe. The bottom of the upper water tank is connected to the middle water tank via a second pipe. An upper valve is installed on the second pipe to control the flow of water inside the second pipe. A first overflow port is opened on the side of the upper water tank, and a second overflow port is opened on the side of the middle water tank. An overflow pipe is connected to the first overflow port and the second overflow port. The lower end of the overflow pipe is connected to the lower water tank. Through the cooperation of the first overflow port, the second overflow port, and the overflow pipe, water in the upper and middle water tanks can be effectively prevented from overflowing from the tank openings, ensuring the safe operation of the system.

[0007] More specifically, the middle water tank and the lower water tank are connected by a third pipe, and a lower valve is installed on the third pipe to control the flow of water inside the third pipe.

[0008] More specifically, the upper surface of the intermediate water tank is provided with a sealing cover, and the surface of the sealing cover is provided with several sets of level gauge interfaces. The reference level gauge is fixedly installed on the sealing cover. Multiple ultrasonic level gauges to be tested can be installed simultaneously or sequentially on the several sets of level gauge interfaces. The reference level gauge and each level gauge to be tested are electrically connected to a computer for recording the data of the reference level gauge calibration.

[0009] More specifically, the upper water tank is equipped with a first controller for controlling the opening and closing of the upper valve and the water pump body, and the middle water tank is equipped with a second controller for controlling the opening and closing of the lower valve and the starting of the water pump body.

[0010] More specifically, a temperature sensor is installed inside the intermediate water tank. The temperature sensor is electrically connected to a temperature controller. The temperature controller controls the heating power of the heating jacket according to the signal fed back by the temperature sensor, so that the water temperature in the intermediate water tank is stabilized at the set target temperature. The heating jacket can also simulate the liquid level detection environment under different temperature conditions, which can be used to verify the measurement stability and temperature drift characteristics of the ultrasonic level gauge under different temperature conditions.

[0011] More specifically, the diversion plate is installed on the inner wall of the intermediate water tank, located below the second pipe. The surface of the diversion plate has a diversion groove with a "V" shaped cross-section. A support rib is provided below the diversion plate, with one end connected to the bottom of the diversion plate and the other end connected to the inner wall of the intermediate water tank. The diversion plate prevents water from the second pipe from falling directly into the intermediate water tank, reducing the impact force of the falling water and improving the stability of the liquid inside the intermediate water tank.

[0012] More specifically, a support plate is installed inside the water tank. The surface of the support plate has holes, and a positioning bearing is installed in the holes. A support screw is inserted into the inner ring of the positioning bearing. A flow-dividing cone is provided on the upper end face of the support screw. The surface of the defoaming plate has threaded holes, and the defoaming plate is threaded to the support screw through the threaded holes. The defoaming plate can reduce water bubbles on the liquid surface and improve the accuracy of subsequent liquid level calibration.

[0013] A calibration method for a liquid level gauge calibration device specifically includes the following steps: S1. First, fill the water tank with water, and then install the ultrasonic level gauge to be tested. S2. Start the water pump body and use the first pipe to inject water from the lower water tank into the upper water tank; S3. Then, when the liquid level in the upper water tank reaches the highest mark, the water pump stops, and then the upper valve opens, allowing the water in the upper water tank to be injected into the middle water tank. S4. When the liquid level in the water tank rises, each liquid level gauge detects the liquid level data and uploads it to the computer. S5. When the water level in the middle tank reaches the highest mark, the second controller will open the lower valve to allow the water in the middle tank to be injected into the lower tank. S6. When the liquid level in the upper water tank reaches the lowest mark, the first controller will close the upper valve to stop the water in the upper water tank from being injected into the middle water tank. S7. As water continues to be injected into the middle water tank, each level gauge detects the level data again and uploads it to the computer for data acquisition during the descent. When the water level in the middle water tank reaches the lowest mark, the lower valve closes, and the second controller in the middle water tank starts the water pump. The system automatically enters the next cycle of verification.

[0014] More specifically, repeat steps S2-S7 to perform multiple cyclic calibrations on the level gauge to be tested, with a minimum of 3 cycles and a default of 5 cycles. The computer records and saves the test data for each cycle. The computer compares and analyzes all collected data based on the preset data range for each point, identifies and marks unqualified level gauges with signal deviations, and saves the data for each point and generates a retrievable data table for inspection personnel to confirm and trace.

[0015] The beneficial effects of this invention are that it provides a liquid level gauge calibration device and calibration method: 1) This invention uses a three-stage water tank structure consisting of an upper tank, a middle tank, and a lower tank. Water is injected into the middle tank by gravity flow from the upper tank, effectively avoiding the liquid level fluctuation problem caused by direct pumping. Then, through coordinated control of the liquid levels in the upper and lower tanks, the liquid level in the middle tank can rise and fall smoothly. Finally, through synchronous data acquisition and computer comparison between the reference level gauge and the ultrasonic level gauge under test, automatic detection of multiple liquid levels across the entire range is achieved. The system's automatic reset function supports continuous detection of batch instruments, greatly improving detection efficiency and consistency.

[0016] 2) By combining the diversion plate and the defoaming plate, the present invention can pass the incoming water containing air bubbles and kinetic energy through the water in sequence to reduce the impact force of the water and the large foam generated in the water, so that the water surface forms a stable, bubble-free liquid surface, providing a highly consistent measurement reference for the reference level gauge. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 This is a schematic diagram of the upward tilting structure at the bottom of the present invention.

[0020] Figure 3 This is a side sectional view of the present invention.

[0021] Figure 4 This is a schematic diagram of the overall structure of the present invention from another angle.

[0022] Figure 5 This is a partial cross-sectional view of the water tank in the structure of this invention.

[0023] Figure 6 yes Figure 5 A magnified structural diagram at point A in the diagram.

[0024] Figure 7 This is a schematic diagram of the structure after the overflow pipe is exposed from another perspective of the present invention.

[0025] In the diagram: 1. Steel frame; 100. Upper part; 101. Middle part; 102. Lower part; 2. Upper water tank; 3. Middle water tank; 4. Reference level gauge; 5. Lower water tank; 6. Water pump body; 7. Drainage plate; 8. Defoaming plate; 9. Heating jacket; 10. First pipe; 11. Second pipe; 12. Upper valve; 13. Third pipe; 14. Lower valve; 15. Sealing cover; 16. Level gauge interface; 17. Computer; 18. First controller; 19. Second controller; 20. Temperature sensor; 21. Drainage channel; 22. Support rib; 23. Support plate; 24. Positioning bearing; 25. Support screw; 26. Diverting cone; 27. Threaded hole; 28. Overflow pipe; 29. ​​First overflow port; 30. Second overflow port. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0027] Example 1: like Figures 1-7 The image shows a liquid level gauge calibration device according to Embodiment 1 of the present invention, comprising: a steel frame 1 for supporting installation and a water pump body 6 for pumping water. The steel frame 1 is divided into an upper part 100, a middle part 101, and a lower part 102. The upper part 100 is equipped with an upper water tank 2 for storing water to be tested. The middle part 101 is equipped with a middle water tank 3, and a reference level gauge 4 is installed on the middle water tank 3 for testing the liquid level inside the middle water tank 3. The lower part 102 is equipped with a lower water tank 5 for storing water flowing down from the middle water tank 3. In addition, by setting up a three-stage water tank structure of upper water tank 2, middle water tank 3, and lower water tank 5, water can be injected into the middle water tank 3 by gravity flow from the upper water tank 2, which effectively avoids the problem of liquid level fluctuation caused by direct injection from the water pump body 6. The intermediate water tank 3 is equipped with a flow guide plate 7 and a defoaming plate 8 to reduce the impact of water flow and eliminate large foam generated in the water, so as to avoid affecting the normal calibration results due to excessive liquid level fluctuations or excessive foam on the liquid surface. The intermediate water tank 3 is equipped with a heating jacket 9, which is electrically connected to an external temperature controller to simulate the liquid level detection environment under different temperature conditions. It can also stabilize the water temperature in the intermediate water tank 3 at the set target temperature. Through the heating control of the heating jacket 9, the liquid level detection environment under different temperature conditions can be simulated to verify the measurement stability and temperature drift characteristics of the ultrasonic level gauge under different temperature conditions.

[0028] Example 2: like Figure 1 and Figure 7As shown, based on Embodiment 1, the following additions are made: the input end of the water pump body 6 is connected to the interior of the lower water tank 5 via a flexible hose, and the output end of the water pump body 6 is connected to the interior of the upper water tank 2 via a first pipe 10, so that water in the lower water tank 5 can be injected into the upper water tank 2 through the first pipe 10. The bottom of the upper water tank 2 is connected to the middle water tank 3 via a second pipe 11. An upper valve 12 is provided on the second pipe 11 to control the flow of water inside the second pipe 11. A first overflow port 29 is provided on the side of the upper water tank 2, and a second overflow port 30 is provided on the side of the middle water tank 3. An overflow pipe 28 is connected to the first overflow port 29 and the second overflow port 30. The lower end of the overflow pipe 28 is connected to the lower water tank 2. Through the cooperation of the first overflow port 29, the second overflow port 30 and the overflow pipe 28, water in the upper water tank 2 and the middle water tank 3 can be effectively prevented from overflowing from the tank openings, ensuring the safe operation of the system. The middle water tank 3 and the lower water tank 5 are connected by a third pipe 13. A lower valve 14 is installed on the third pipe 13 to control the flow of water inside the third pipe 13.

[0029] Example 3: like Figure 1 and Figure 2 As shown, based on Embodiment 1, the following addition is made: a sealing cover 15 is provided on the upper surface of the intermediate water tank 3, and several sets of level gauge interfaces 16 are opened on the surface of the sealing cover 15. A reference level gauge 4 is fixedly installed on the sealing cover 15. Multiple ultrasonic level gauges to be tested can be installed simultaneously or sequentially on the several sets of level gauge interfaces 16. The reference level gauge 4 and each level gauge to be tested are electrically connected to the computer 17 to record the data of the calibration of the reference level gauge 4. The reference level gauge 4 adopts a pulse level gauge with a measurement accuracy of ±0.5mm and a resolution of 0.1mm, serving as a standard reference for the entire testing process. The reference level gauge 4 and each level gauge to be tested connected to the several sets of level gauge interfaces 16 are electrically connected to the computer 17. During the testing process, all level gauges collect level signals in real time and transmit them to the computer 17. The computer 17 has a preset standard data model for each detection point. Specifically, the effective detection range of the intermediate water tank 3 is set to 0-500mm, and no less than 20 detection points are selected uniformly or non-uniformly within it. For example, detection points can be set at 50mm, 100mm, 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, and 450mm. The density can be increased to one point every 10mm in commonly used intervals as needed. Each detection point has a preset theoretical liquid level value and allowable deviation range. Specific judgment parameters are as follows: First, the absolute error at a single point: at each detection point, the difference between the reading of the level gauge to be tested and the reading of the reference level gauge 4 should not exceed ±2mm; Then, linear error: within the full range, the difference between the maximum and minimum absolute errors at each detection point should not exceed 3mm, calculated by taking the average value of multiple cycles; Secondly, the return error: the difference between the values ​​measured at the same detection point during the liquid level rise and fall should not exceed 1.5 mm, and the average value of multiple cycles should be used for calculation; Then, repeatability error: the maximum difference between the values ​​obtained by the same level gauge under test at the same detection point after multiple cyclic measurements should not exceed 1 mm; Final cycle consistency: The proportion of qualified cycles to the total number of cycles should not be less than 80%, that is, at least 4 out of 5 cycles should be qualified.

[0030] Example 4: like Figures 3-5 As shown, based on Embodiment 1, the following is added: a first controller 18 is provided in the upper water tank 2 for controlling the opening and closing of the upper valve 12 and the water pump body 6; a second controller 19 is provided in the middle water tank 3 for controlling the opening and closing of the lower valve 14 and the starting of the water pump body 6. The first controller 18 can control the opening and closing of the upper valve 12 and the water pump body 6, and the second controller 19 can control the opening and closing of the lower valve 14 and the starting of the water pump body 6, which facilitates the flow of water between the upper water tank 2, the middle water tank 3 and the lower water tank 5. A temperature sensor 20 is installed inside the intermediate water tank 3. The temperature sensor 20 is electrically connected to the temperature controller. The temperature controller controls the heating power of the heating jacket 9 according to the signal fed back by the temperature sensor 20, so that the water temperature in the intermediate water tank 3 is stabilized at the set target temperature. The temperature controller controls the heating power of the heating jacket 9 according to the signal fed back by the temperature sensor 20. Through the heating control of the heating jacket 9, the liquid level detection environment under different temperature conditions can be simulated, which is used to verify the measurement stability and temperature drift characteristics of the ultrasonic level gauge under different temperature conditions.

[0031] Example 5: like Figure 5 and Figure 6 As shown, based on Embodiment 1, the following addition is made: a diversion plate 7 is installed on the inner wall of the intermediate water tank 3. The diversion plate 7 is located below the second pipe 11. A diversion groove 21 is opened on the surface of the diversion plate 7. The cross-section of the diversion groove 21 is "V" shaped. A support rib 22 is provided below the diversion plate 7. One end of the support rib 22 is connected to the bottom of the diversion plate 7, and the other end of the support rib 22 is connected to the inner wall of the intermediate water tank 3. The support rib 22 can improve the overall support strength of the diversion plate 7. When water enters the intermediate water tank 3 from the second pipe 11, it first falls on the diversion plate 7. Through the diversion groove 21 opened on the surface of the diversion plate 7, the water falling from the second pipe 11 can be prevented from directly acting on the intermediate water tank 3, causing fluctuations in the liquid level inside the intermediate water tank 3. A support plate 23 is installed inside the intermediate water tank 3. The surface of the support plate 23 has holes, and a positioning bearing 24 is installed inside each hole. A support screw 25 is inserted into the inner ring of the positioning bearing 24. A flow-diverting cone 26 is installed on the upper end face of the support screw 25. A threaded hole 27 is opened on the surface of the defoaming plate 8, and the defoaming plate 8 is threadedly connected to the support screw 25 through the threaded hole 27. When water flows from the diversion channel 21 onto the flow-diverting cone 26, the downstream water is evenly guided to the surrounding area, dispersing the concentrated water flow and eliminating direct impact energy. The defoaming plate 8 can prevent excessive air bubbles on the liquid surface inside the intermediate water tank 3 from affecting the test results. In addition, when it is necessary to adjust the height of the defoaming plate 8 in the intermediate water tank 3, the support screw 25 can be rotated in conjunction with the positioning bearing 24, so that the height of the defoaming plate 8 threaded on the support screw 25 can be adjusted. The support screw 25 is fixed by the positioning bearing 24, which also makes it easy to separate the support screw 25 from the support plate 23 later. Simply remove the positioning bearing 24 from the hole opened on the surface of the support plate 23.

[0032] A calibration method for a liquid level gauge calibration device specifically includes the following steps: S1. First, fill the lower water tank 5 with water, and then install the ultrasonic level gauge to be tested. S2. Start the water pump body 6 and use the first pipe 10 to inject water from the lower water tank 5 into the upper water tank 2. S3. Then, when the liquid level in the upper water tank 2 reaches the highest mark point, the water pump body 6 stops, and then the upper valve 12 opens, allowing the water in the upper water tank 2 to be injected into the middle water tank 3. S4. When the liquid level in the water tank 3 rises, each liquid level gauge detects the liquid level data and uploads it to the computer 17. S5. When the water level in the middle water tank 3 reaches the highest mark, the second controller 19 opens the lower valve 14 to inject the water in the middle water tank 3 into the lower water tank 5. S6. When the liquid level in the upper water tank 2 reaches the lowest mark point, the first controller 18 closes the upper valve 12, so that the water in the upper water tank 2 stops being injected into the middle water tank 3. S7. As water continues to be injected into the middle water tank 3 into the lower water tank 5, during the process of the liquid level dropping, each liquid level gauge will detect the liquid level data again and upload it to the computer 17 for data acquisition of the dropping segment. When the liquid level in the middle water tank 3 reaches the lowest mark point, the lower valve 14 will be closed. At the same time, the second controller 19 in the middle water tank 3 will control the water pump body 6 to start, and the system will automatically enter the next cycle of verification.

[0033] Then repeat steps S2-S7 to perform multiple cyclic calibrations on the level gauge to be tested, with a minimum of 3 cycles and a default of 5 cycles. Computer 17 records and saves the test data for each cycle. Computer 17 compares and analyzes all collected data according to the preset data range of each point, identifies and marks unqualified level gauges with signal deviations, and saves the data of each point and generates a retrievable data table for inspection personnel to confirm and trace.

[0034] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A liquid level gauge calibration device, comprising: The steel frame (1) for supporting the installation and the water pump body (6) for pumping water are characterized in that: The steel frame (1) is divided into an upper part (100), a middle part (101) and a lower part (102). The upper part (100) is equipped with an upper water tank (2) for storing water to be tested. The middle part (101) is equipped with a middle water tank (3) and a reference level gauge (4) is installed on the middle water tank (3) for testing the liquid level inside the middle water tank (3). The lower part (102) is equipped with a lower water tank (5) for storing water flowing down from the middle water tank (3). The middle water tank (3) is equipped with a flow guide plate (7) and a defoaming plate (8) to reduce the impact force of the water flow and eliminate large foam generated in the water. The middle water tank (3) is equipped with a heating jacket (9) on the outside. The heating jacket (9) is electrically connected to an external temperature controller to simulate the liquid level detection environment under different temperature conditions.

2. The liquid level gauge calibration device according to claim 1, characterized in that, The input end of the water pump body (6) is connected to the interior of the lower water tank (5) through a hose. The output end of the water pump body (6) is connected to the interior of the upper water tank (2) through the first pipe (10). The bottom of the upper water tank (2) is connected to the middle water tank (3) through the second pipe (11). An upper valve (12) is provided on the second pipe (11) to control the flow of water inside the second pipe (11). A first overflow port (29) is provided on the side of the upper water tank (2). A second overflow port (30) is provided on the side of the middle water tank (3). An overflow pipe (28) is connected between the first overflow port (29) and the second overflow port (30). The lower end of the overflow pipe (28) is connected to the lower water tank (2).

3. The liquid level gauge calibration device according to claim 1, characterized in that, The middle water tank (3) and the lower water tank (5) are connected by a third pipe (13), and a lower valve (14) is provided on the third pipe (13) to control the flow of water inside the third pipe (13).

4. The liquid level gauge calibration device according to claim 1, characterized in that, The upper surface of the water tank (3) is provided with a sealing cover (15). Several sets of liquid level gauge interfaces (16) are opened on the surface of the sealing cover (15). The reference liquid level gauge (4) is fixedly installed on the sealing cover (15). Several sets of liquid level gauge interfaces (16) can simultaneously or sequentially install multiple ultrasonic liquid level gauges to be tested. The reference liquid level gauge (4) and each liquid level gauge to be tested are electrically connected to the computer (17) for recording the data of the calibration of the reference liquid level gauge (4).

5. The liquid level gauge calibration device according to claim 1, characterized in that, The upper water tank (2) is equipped with a first controller (18) for controlling the opening and closing of the upper valve (12) and the water pump body (6). The middle water tank (3) is equipped with a second controller (19) for controlling the opening and closing of the lower valve (14) and the starting of the water pump body (6).

6. The liquid level gauge calibration device according to claim 1, characterized in that, The water tank (3) is equipped with a temperature sensor (20), which is electrically connected to a temperature controller. The temperature controller controls the heating power of the heating jacket (9) based on the signal fed back by the temperature sensor (20), so that the water temperature in the water tank (3) is stabilized at the set target temperature.

7. The liquid level gauge calibration device according to claim 1, characterized in that, The diversion plate (7) is installed on the inner wall of the middle water tank (3). The diversion plate (7) is located below the second pipe (11). The surface of the diversion plate (7) is provided with a diversion groove (21). The cross section of the diversion groove (21) is "V". A support rib (22) is provided below the diversion plate (7). One end of the support rib (22) is connected to the bottom of the diversion plate (7), and the other end of the support rib (22) is connected to the inner wall of the middle water tank (3).

8. The liquid level gauge calibration device according to claim 1, characterized in that, A support plate (23) is installed inside the water tank (3). The support plate (23) has a hole on its surface and a positioning bearing (24) is installed inside the hole. A support screw (25) is inserted into the inner ring of the positioning bearing (24). A diverting cone (26) is provided on the upper end face of the support screw (25). A threaded hole (27) is provided on the surface of the defoaming plate (8). The defoaming plate (8) is threaded to the support screw (25) through the threaded hole (27).

9. A calibration method for a liquid level gauge calibration device, based on the liquid level gauge calibration device according to any one of claims 1-8, characterized in that, Specifically, it includes the following steps: S1. First, fill the water tank (5) with water, and then install the ultrasonic level gauge to be tested. S2. Start the water pump body (6) and use the first pipe (10) to inject water from the lower water tank (5) into the upper water tank (2); S3. Then, when the liquid level in the upper water tank (2) reaches the highest mark point, the water pump body (6) stops, and then the upper valve (12) opens, so that the water in the upper water tank (2) is injected into the middle water tank (3). S4. When the liquid level in the water tank (3) rises, each liquid level gauge detects the liquid level data and uploads it to the computer (17). S5. When the water level in the middle water tank (3) reaches the highest mark, the second controller (19) opens the lower valve (14) to inject the water in the middle water tank (3) into the lower water tank (5). S6. When the liquid level in the upper water tank (2) reaches the lowest mark point, the first controller (18) closes the upper valve (12) to stop the water in the upper water tank (2) from being injected into the middle water tank (3). S7. Water in the middle water tank (3) continues to be injected into the lower water tank (5). During the liquid level drop, each liquid level gauge detects the liquid level data again and uploads it to the computer (17) for data acquisition of the drop segment. When the liquid level in the middle water tank (3) reaches the lowest mark point, the lower valve (14) closes. At the same time, the second controller (19) in the middle water tank (3) controls the water pump body (6) to start, and the system automatically enters the next cycle of verification.

10. The calibration method for a liquid level gauge calibration device according to claim 9, characterized in that, Repeat steps S2-S7 to perform multiple cyclic calibrations on the level gauge to be tested, with a minimum of 3 cycles and a default of 5 cycles. The computer (17) records and saves the test data for each cycle. The computer (17) compares and analyzes all collected data according to the preset data range of each point, identifies and marks unqualified level gauges with signal deviations, and saves the data of each point and generates a retrievable data table for inspection personnel to confirm and trace.

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