A gamma ray based tank parameter measurement device and method

Abstract

This invention provides a gamma-ray-based tank parameter measurement device, installed on a working tank, comprising: a radiation source, a level gauge, at least two thickness gauges, and a control host. The installation height of each thickness gauge corresponds to the installation height of one of the radiation sources, making the thickness gauge and radiation source radially symmetrical on the working tank, forming an independent through-beam measurement optical path. The control host receives the level signal and triggers the thickness gauge to perform wall thickness measurement when the material level drops below the installation height of one of the thickness gauges. This invention significantly extends equipment lifespan by having the control host trigger measurement only when the material level drops below the installation position of a certain thickness gauge, while the thickness gauge remains silent at other times. It also ensures that measurements are performed in an empty tank window free from material interference, resulting in accurate and valid data. The hysteresis range setting prevents frequent start-stop cycles caused by level fluctuations, ensuring stable and reliable system operation.

Description

Technical Field

[0001] This invention relates to the field of industrial nuclear radiation measurement technology, specifically to a device and method for measuring tank parameters based on gamma rays. Background Technology

[0002] In industries such as chemical, energy, and metallurgy, enclosed tanks such as reaction vessels, storage tanks, and slurry tanks are core production equipment. During long-term operation, materials inside the tanks (such as mineral slurries, chemical slurries, and viscous media) gradually form a layer of crystals, dirt, and deposits on the inner walls, known as the wall coating. The thickness of this wall coating directly affects the effective volume, heat transfer efficiency, and production efficiency of the tank, and in severe cases, can lead to pipe blockage, equipment corrosion, and even safety accidents. Therefore, online monitoring of the wall coating thickness inside the tank is a crucial requirement for ensuring safe production and scientific maintenance.

[0003] Currently, nuclear radiation level gauges are widely used in industry for monitoring material levels inside tanks. Their principle is based on the use of gamma rays emitted from a radiation source installed on one side of the tank, which penetrate the tank and the material. A detector installed on the opposite side of the tank receives the attenuated gamma ray signal, and the level is determined based on changes in gamma ray intensity. Nuclear radiation level gauges are non-contact, unaffected by high temperature, high pressure, or corrosive environments, and can achieve continuous online monitoring of material levels.

[0004] However, when a wall-mounted layer exists on the inner wall of the tank, this layer absorbs additional radiation, resulting in a lower overall signal strength received by the detector and causing inaccuracies in the level gauge's measurement results. Currently, the only methods typically involve shutting down the tank and manually entering for inspection, or using a separate thickness gauge for offline, single-point sampling. These methods cannot achieve online automated measurement, have low inspection efficiency, and pose personnel safety risks. For tanks subjected to high temperature, high pressure, and strong corrosion, shutting down the tank and opening it is extremely costly and cannot be performed frequently. Summary of the Invention

[0005] This invention provides a tank parameter measuring device and method based on gamma rays, specifically solving the problem of simultaneously measuring the thickness of the inner wall coating at multiple points and continuously monitoring the material level through an automated system.

[0006] A gamma-ray-based tank parameter measuring device, installed on a working tank, includes: a radiation source installed on the outer wall of the working tank; a level gauge installed on the outer wall of the working tank opposite to the radiation source and arranged along the height direction of the working tank for continuously monitoring the material level in the working tank and outputting a level signal; at least two thickness gauges installed at intervals along the height direction of the working tank on one side of the outer wall of the working tank; and a control host electrically connected to the level gauge and each thickness gauge; wherein the installation height of each thickness gauge corresponds to the installation height of one of the radiation sources, such that the thickness gauge and the radiation source are symmetrical in the radial direction of the working tank, forming an independent through-beam measurement optical path; the control host receives the level signal and triggers the thickness gauge to perform wall thickness measurement when the material level drops below the installation height of one of the thickness gauges.

[0007] Furthermore, the radiation source is fixed inside a shielded source container, which is installed on the outer wall of the working container. The shielded source container is provided with a collimation hole for directing the γ-ray beam emitted by the radiation source to the corresponding thickness gauge.

[0008] Furthermore, the level gauge and each of the thickness gauges include a crystal sensor, a photomultiplier tube, a high-voltage module, a preamplifier circuit, a cable, and a housing for encapsulating the above components; the crystal sensor of the level gauge is made of PVT material and extends along the height direction, and the crystal sensor of the thickness gauge is made of Na1 material.

[0009] Furthermore, in the level gauge and each of the thickness gauges, the photomultiplier tubes are optically coupled to the corresponding crystal sensor, and the high-voltage module and the preamplifier circuit are electrically connected to the photomultiplier tubes respectively.

[0010] Furthermore, the installation height of all the thickness gauges does not exceed the detection range of the level gauge along the height direction.

[0011] Furthermore, the control host includes: a signal input interface, electrically connected to the level gauge and each of the thickness gauges; and a control output interface, electrically connected to each of the thickness gauges, used to send a trigger signal or an exit signal to each of the thickness gauges respectively.

[0012] A method for measuring tank parameters based on gamma rays includes the following steps: the level gauge continuously monitors the material level in the working tank and outputs a level signal to the control host; the control host triggers the corresponding thickness gauge to perform wall thickness measurement when the material level drops below the installation height of one of the thickness gauges according to the level signal; the triggered thickness gauge receives gamma rays that penetrate the tank wall and the wall layer of the working tank, converts the optical signal into an electrical signal and transmits it to the control host, and the control host completes the wall thickness calculation.

[0013] Furthermore, the control host presets a start threshold and an exit threshold for each thickness gauge. The start threshold is lower than the exit threshold, and the two form a hysteresis interval. When the material level drops below the start threshold of one of the thickness gauges and remains below it for a preset duration, the thickness gauge is triggered to perform measurement. When the material level rises above the exit threshold of the thickness gauge and remains above it for a preset duration, the thickness gauge is controlled to exit measurement.

[0014] Furthermore, the control host controls the triggered thickness gauge to perform one valid measurement and then exits the operation; or, controls the triggered thickness gauge to continue performing measurements until an exit signal is received.

[0015] Furthermore, it also includes: after completing a unloading cycle, the control host will associate the wall thickness data of each thickness gauge acquired in sequence with the corresponding installation height position to generate the distribution information of the wall thickness along the height direction of the working tank.

[0016] Beneficial effects: This invention utilizes a functionally separated device architecture and a multi-point trigger control method to simultaneously achieve multi-point measurement of the inner wall thickness and continuous monitoring of the material level within a single automated system on a single tank. Specifically, the level gauge and thickness gauge are physically independent. The level gauge employs a PVT crystal extending along the height of the tank, focusing on continuous monitoring of the material level and outputting the level signal; the thickness gauge employs a NAL crystal installed at various preset measurement positions, focusing on high-precision calculation of the wall thickness. Both detector devices have simple structures and low manufacturing costs, and the level signal and thickness signal are completely separated in the physical link, avoiding signal crosstalk and circuit compatibility issues.

[0017] In terms of control method, the control host, based on the real-time level signal output by the level gauge, only triggers the thickness gauge to perform wall thickness measurement when the material level drops below the installation position of a certain thickness gauge; otherwise, the thickness gauge remains silent. This trigger control strategy compresses the working period of the thickness gauge's high-voltage module and photomultiplier tube into an extremely short measurement window, significantly reducing the aging rate of core components and extending the equipment's service life. Simultaneously, it ensures that each measurement is performed under conditions where the tank wall is completely exposed to an empty tank environment without material interference, guaranteeing the authenticity and validity of the measurement data. Furthermore, the preset start and stop thresholds in the control host form a hysteresis range, effectively preventing frequent start-stop of the thickness gauge due to level fluctuations. Each detector is installed and operates independently; a single fault does not affect other functions, maintenance is convenient, and adding thickness measurement points only requires adding corresponding radiation sources and thickness gauges, making the system flexible for expansion. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the measuring device in an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the level gauge in an embodiment of the present invention; Figure 3 This is a flowchart illustrating the measurement method in an embodiment of the present invention. Detailed Implementation

[0019] In this embodiment of the invention, directional indicators (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of each component in a specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0020] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0021] Example 1 Please see Figure 1 This embodiment provides a tank parameter measuring device and method based on gamma rays, which is installed on a working tank 1. The device in this embodiment includes three radiation sources 2, a level gauge 3, three thickness gauges 4, and a control host 5.

[0022] Three radiation sources 2 are installed at intervals along the height of the working tank 1 on the first side of the outer wall of the working tank 1. Each radiation source 2 is fixed inside a shielded source tank, which is equipped with a collimation hole to direct the gamma-ray beam emitted by the radiation source 2 to the thickness gauge 4 corresponding to that radiation source 2. The radiation source 2 can be an isotope source such as cesium-137 or cobalt-60, which emits gamma rays with strong penetrating power and can effectively penetrate the tank wall and the wall-mounted layer. The shielded source tank is made of heavy metal materials such as lead or tungsten and has sufficient shielding thickness to ensure the radiation safety of the surrounding environment.

[0023] The level gauge 3 is installed on the second side of the outer wall of the working tank 1, opposite to the first side where the radiation source 2 is located. The level gauge 3 is arranged along the height direction of the working tank 1. The level gauge 3 receives gamma rays that penetrate the tank wall and the material. The level gauge 3 covers the range of material level changes in the tank along the height direction and outputs a continuous level signal according to the difference in the degree of radiation attenuation between the material section and the empty tank section.

[0024] It is worth noting that the operation of the level gauge 3 does not depend on a specific radiation source 2, but rather on receiving gamma rays emitted by the first side radiation source 2 that penetrate the tank.

[0025] Three thickness gauges 4 are installed at intervals along the height of the working tank 1 on the second side of the outer wall of the working tank 1, i.e., on the same side as the level gauge 3. The installation heights of the three thickness gauges 4 correspond to the upper, middle, and lower parts of the working tank 1, respectively. The Nal crystal sensor of each thickness gauge faces the corresponding radiation source 2 opposite it and is perpendicular to the extension direction of the level gauge 3. The installation height of each thickness gauge 4 is within the effective detection range of the level gauge 3, ensuring that when the material level changes, the level gauge 3 can accurately determine whether the material level has dropped below the installation height of each thickness gauge 4.

[0026] The uppermost thickness gauge 4 and the uppermost radiation source 2 are symmetrically installed radially in the working tank 1, with corresponding installation heights, forming an independent first through-beam measurement optical path. Similarly, the middle thickness gauge 4 and the middle radiation source 2, and the lowermost thickness gauge 4 and the lowermost radiation source 2, respectively form the second and third through-beam measurement optical paths. Each thickness gauge 4 only receives the γ-rays emitted from its corresponding radiation source 2 that penetrate the tank wall and the wall-mounted layer of the working tank 1, without interference from other radiation sources 2.

[0027] The control host 5 is electrically connected to the level gauge 3 and each thickness gauge 4, respectively, to receive the level signal and other data output by the level gauge 3, and to send control signals to each thickness gauge 4. Based on changes in the level signal, the control host 5 sends a trigger signal to the thickness gauge 4 when it determines that the material level has dropped below the installation height of one of the thickness gauges 4, controlling it to start and perform wall thickness measurement; when it determines that the material level has risen back above the installation height of the thickness gauge 4, it sends an exit signal to the thickness gauge 4, controlling it to exit measurement.

[0028] The structure of each component of the device is described in detail below.

[0029] Each radiation source 2 is fixed inside a shielded source container. The shielded source container is made of heavy metal materials such as lead or tungsten and has sufficient shielding thickness to ensure that the radiation dose in non-beam-emission directions is below the national standard limit. A collimation hole is opened on the side of the shielded source container facing the corresponding thickness gauge 4. The shape, size and orientation of the collimation hole are precisely designed so that the gamma rays emitted by the radiation source 2 can be directed to the corresponding thickness gauge 4 at a predetermined angle, while minimizing radiation leakage in other directions.

[0030] Please see Figure 2 The level gauge 3 includes a crystal sensor 31, a photomultiplier tube 32, a high-voltage module 33, a preamplifier circuit 34, a cable 36, and a housing 35 encapsulating the above components. In the level gauge 3, each photomultiplier tube 32 is optically coupled to its corresponding crystal sensor 31, and the high-voltage module 33 and the preamplifier circuit 34 are electrically connected to the photomultiplier tube 32. The high-voltage module 33 provides a stable operating voltage to the photomultiplier tube 32, and the preamplifier circuit 34 receives the electrical pulse signal output by the photomultiplier tube 32 and performs amplification, energy spectrum analysis, spectrum stabilization, and interference removal processing. The cable 36 is used to transmit the processed signal to the control host 5 and simultaneously power the internal circuit modules. The housing 35 encapsulates the crystal sensor 31, photomultiplier tube 32, high-voltage module 33, and preamplifier circuit 34 into a single unit, providing mechanical protection and electromagnetic shielding. The thickness gauge 4 is similar to the level gauge 3 and also includes the above structure, but differs in the crystal, preamplifier circuit, and external dimensions.

[0031] The crystal sensor 31 of the level gauge 3 is made of polyvinyl toluene (PVT) crystal and extends along the height direction of the working tank 1, covering the range of material level changes within the working tank 1. When gamma rays penetrate the tank wall and the material inside the tank and reach the PVT crystal sensor 31, the attenuation of the rays differs between the material section and the empty tank section—the material section has strong absorption capacity, resulting in a significant attenuation of the ray intensity passing through the material; the empty tank section has weak absorption capacity, resulting in a smaller attenuation of the ray intensity. Therefore, the intensity of the rays received by the PVT crystal sensor 31 at different positions along the height direction varies. These differential signals are converted into electrical signals by the photomultiplier tube 32 and then resolved by the control host 5 into a continuous material level percentage signal.

[0032] Each thickness gauge 4 uses a crystal sensor 31 made of sodium iodide (Nal(Ti)) scintillator crystal. Nal crystals have high density and light output, resulting in excellent detection efficiency for gamma rays, making them suitable for precise thickness measurement. The thickness gauge 4 measures the wall thickness based on the physical law of gamma ray intensity attenuation upon penetration of the medium. When a beam of gamma rays penetrates the tank wall and the wall layer, its attenuation follows this law: In the formula l x Let be the radiation intensity after passing through the tank wall and the coating layer, l be the radiation intensity before entering the tank wall and coating layer at calibration, e be the natural constant, μ be the mass absorption coefficient of the tank wall and coating layer for radiation, ρ be the density of the coating layer, d be the measurement path (i.e., the coating thickness), λ be the source decay constant, and t be the source decay time. By mathematically transforming the above formulas, the formula for calculating the coating thickness can be obtained:

[0033] Since the material and density of the wall-mounted layer are usually known, the intensity of the penetrating rays can be detected by measuring the intensity of the penetrating rays. x The wall thickness d can then be calculated by reverse calculation. The introduction of the source decay correction term λt ensures that the measurement results are not affected by the decay of the radioactive source 2 itself during long-term operation. Taking the upper thickness gauge 4 as an example, its crystal sensor 31 receives γ-rays that penetrate the upper tank wall of the working tank 1 and the wall layer there. Based on the attenuation of the ray intensity and the above formula, the wall thickness at that location can be calculated. Similarly, the middle thickness gauge 4 and the lower thickness gauge 4 are responsible for measuring the wall thickness in the middle and lower parts of the working tank 1, respectively. The measurements of each thickness gauge 4 are independent, operating only within its corresponding measurement window and are not affected by the measurement status of other thickness gauges 4.

[0034] It should be noted that although the level gauge 3 and thickness gauge 4 have similar internal basic components, their preamplifier circuits 34 differ in specific circuit parameters and signal processing methods. The preamplifier circuit 34 of the level gauge 3 focuses on the stable output of continuous analog signals to support real-time continuous monitoring of the material level; while the preamplifier circuit 34 of the thickness gauge 4 focuses on pulse amplitude analysis and energy spectrum stabilization processing to meet the requirements of high-precision calculation of wall thickness.

[0035] As one implementation method, the installation height of all thickness gauges 4 does not exceed the detection range of the level gauge 3 along the height direction. As the material level in the working tank 1 gradually decreases from full to empty, the level gauge 3 can accurately determine whether the material level has dropped below the installation height of each thickness gauge 4, thereby providing accurate trigger judgment basis for the control host 5.

[0036] In one implementation, the control host 5 includes a signal input interface and a control output interface. The signal input interface is electrically connected to the cable 36 of the level gauge 3 and the cables 36 of each thickness gauge 4, and is used to receive the level signal output by the level gauge 3 and the thickness measurement signal output by each thickness gauge 4. The control output interface is electrically connected to each thickness gauge 4, and is used to send trigger signals or exit signals to each thickness gauge 4 respectively. The control host 5 also includes a processor and a memory. The processor is used to execute the trigger judgment logic and the thickness calculation program. The memory is used to store preset control parameters such as the start threshold, exit threshold, and hysteresis interval corresponding to each thickness gauge 4, as well as the wall thickness data measured by each thickness gauge 4 and the corresponding measurement time, installation height, and other information.

[0037] The measurement method of this device is described in detail below.

[0038] Please see Figure 3 In the initial state, the working tank 1 is filled with material, and the material level is at full or high. The level gauge 3 enters continuous monitoring mode from the moment the device is powered on. PVT crystals in each segment along the height direction continuously receive gamma rays penetrating the tank wall and material of the working tank 1. The optical signal is converted into an electrical pulse signal by a photomultiplier tube 32, processed by a preamplifier circuit 34, and then output to the control host 5 in real time via cable 36. The control host 5 receives the level signal through a signal input interface, and the processor analyzes the level signal to determine the current material level height or percentage.

[0039] The control host 5 has preset start-up and exit thresholds for each thickness gauge 4, and the start-up and exit thresholds form a hysteresis range. The start-up and exit thresholds of the three thickness gauges 4 are preset according to their respective installation heights and stored in the memory of the control host 5.

[0040] As the working tank 1 begins unloading, the material level gradually decreases. The control host 5 continuously compares the real-time material level signal with the preset activation thresholds of each thickness gauge 4. When it is determined that the material level has dropped below the activation threshold of the uppermost thickness gauge 4, and this state continues for a preset time, the control host 5 confirms that the thickness gauge 4 is completely exposed to the empty tank environment and sends a trigger signal to the uppermost thickness gauge 4 through the control output interface. After receiving the trigger signal, the uppermost thickness gauge 4 starts working. Its Na1 crystal sensor 31 receives γ-rays that penetrate the upper part of the working tank 1 and the wall layer there. The light signal is converted into an electrical pulse signal by the photomultiplier tube 32, amplified and processed by the preamplifier circuit 34, and then transmitted to the control host 5 through the cable 36. The control host 5 calculates the wall thickness value at the measurement point according to the wall thickness calculation formula based on the received signal, stores it in the memory, and finally displays it on the display screen of the control host 5.

[0041] Subsequently, the material level continued to decrease. The control unit 5 sequentially triggered the middle thickness gauge 4 and the bottom thickness gauge 4 in the same manner to perform measurements and obtain the wall thickness values ​​at the corresponding locations. Throughout the unloading process, since each measurement was performed after the material level had dropped below the installation height of the thickness gauge 4 and the tank wall section was completely exposed to the empty tank environment, the X-rays only penetrated the tank wall and the wall coating layer without passing through the material layer. Therefore, the measured wall thickness data was accurate and valid.

[0042] When the working tank 1 is refilled and the material level rises, the control host 5, after determining that the material level has risen above the exit threshold of a certain thickness gauge 4 for a preset time, sends an exit signal to the thickness gauge 4 through the control output interface, controlling it to exit measurement. The hysteresis range formed between the start threshold and the exit threshold effectively prevents frequent start-stop of the thickness gauge 4 due to material level fluctuations.

[0043] Example 2 The difference between this embodiment and Embodiment 1 lies in the measurement mode of the thickness gauge 4.

[0044] In this embodiment, the control host 5 controls the triggered thickness gauge 4 to perform one valid measurement and then exits operation, returning to a silent state. A valid measurement means that the thickness gauge 4 completes a full signal acquisition, conversion, and transmission process, and the control host 5 receives a set of valid thickness data. After a valid measurement is completed, the control host 5 no longer sends measurement commands to the thickness gauge 4, and the thickness gauge 4 returns to a silent state. When the material level continues to drop below the installation height of the next thickness gauge 4, the control host 5 triggers that thickness gauge 4 to perform one valid measurement in the same manner.

[0045] The single-measurement mode ensures that each thickness gauge 4 operates within a very short measurement window, minimizing the operating time of the high-voltage module 33 and photomultiplier tube 32. This significantly reduces the rate of equipment aging and extends the service life of the thickness gauge 4. Simultaneously, the system consumes little power and generates minimal heat, making it suitable for long-term online operation.

[0046] Example 3 The difference between this embodiment and Embodiment 1 lies in the different measurement modes of the thickness gauge 4.

[0047] In this embodiment, the control host 5 controls the triggered thickness gauge 4 to continue operating after performing a measurement, but does not immediately stop working until it receives an exit signal. Before the material level rises, the control host 5 repeatedly sends measurement commands to the thickness gauge 4 at preset time intervals, or the thickness gauge 4 continuously performs measurements and outputs signals in a continuous mode. Thus, the control host 5 can obtain multiple sets of continuous data on the wall thickness at the measurement point over time in an empty tank state.

[0048] This continuous measurement mode is applicable to the following scenario: the working tank 1 is a high-temperature, high-pressure tank. After the material is emptied, the temperature inside the tank drops sharply. Due to the difference in thermal expansion coefficients between the wall-mounted layer and the metal tank, the wall-mounted layer may undergo structural changes such as cracking, detachment, or shrinkage. Through continuous measurement, the control host 5 can record the entire process curve of the wall-mounted layer thickness changing with the temperature drop, providing key data that cannot be obtained by traditional methods for process optimization, cleaning cycle decisions, and tank maintenance.

[0049] Example 4 The difference between this embodiment and Embodiment 1 is that the control host 5 also has the function of generating wall thickness distribution information.

[0050] After completing a full unloading cycle, the control host 5 sequentially acquires the wall thickness data from each thickness gauge 4 and correlates it with their respective installation height positions to generate wall thickness distribution information along the height direction of the working tank 1. This distribution information can be a set of discrete data or a wall thickness distribution curve generated through interpolation or curve fitting. The control host 5 outputs this distribution information to a display or remote monitoring terminal, allowing operators to visually view the wall thickness at different height positions of the tank, identify the areas with the most severe wall adhesion, and thus arrange targeted cleaning or maintenance plans.

[0051] Although the thickness gauges 4 are triggered sequentially at different times during the unloading cycle, rather than measuring simultaneously, the control host 5 can filter the last valid measurement values ​​of each thickness gauge 4 in the empty tank state, ensuring a certain degree of consistency in the distribution information. Furthermore, the control host 5 can store data from multiple unloading cycles, generating a trend chart of the wall thickness variation, reflecting the accumulation or changes of the wall layer during long-term operation, providing data support for predictive maintenance.

[0052] Example 5 The difference between this embodiment and Embodiment 1 lies in the system's scalability and the structure of the level gauge 3.

[0053] Depending on the size, material characteristics, or process requirements of the working tank 1, more than three thickness gauges 4 can be installed on the outer wall of the working tank 1, such as four, five, or even more. These thickness gauges 4 are distributed along the height direction as needed, and the installation spacing can be uniform or varied according to the differences in the tendency of wall adhesion in different areas of the tank. For example, the installation density of thickness gauges 4 can be increased at the bottom of the tank or in areas with the most severe wall adhesion or liquid surface fluctuations to obtain higher resolution information on the wall adhesion thickness distribution. Correspondingly, the number of radiation sources 2 is equal to the number of thickness gauges 4. Each newly added thickness gauge 4 is symmetrically installed radially on the working tank 1 with a corresponding newly added radiation source 2, forming an independent through-beam measurement optical path. Each newly added thickness gauge 4 is electrically connected to the control host 5, and its triggering logic and measurement mode are the same as those in the above embodiments.

[0054] Furthermore, when the height of the working tank 1 exceeds the length of a single PVT crystal unit, the level gauge 3 can be constructed by splicing multiple PVT crystal units end-to-end along the height direction. Adjacent PVT crystal units are connected via optical coupling or electrical signal cascading, allowing the signals from each PVT crystal unit to be effectively integrated or read separately. The total effective detection length of the spliced ​​level gauge 3 can cover a larger height range of the working tank 1, meeting the level monitoring needs of large tanks.

[0055] It is worth noting that because the gamma rays emitted by a radioactive source scatter in a cone or fan shape, the beam emitted from a single source can cover multiple detectors within a certain height range on the opposite side. Therefore, in some configurations, one radioactive source can simultaneously correspond to one level gauge and one or more thickness gauges; that is, the number of radioactive sources can be less than the sum of the number of level gauges and thickness gauges. For example, in cases where the tank height is small or the radioactive source activity is high, a radioactive source can be installed on one side of the tank, and one level gauge and two thickness gauges can be installed on the opposite side. All three gauges are located within the radiation coverage area of ​​the radioactive source and receive the gamma rays penetrating the tank. This configuration reduces the number of radioactive sources used and lowers the complexity of radiation safety management.

[0056] Example 6 In this embodiment, the output signals of the level gauge 3 and each thickness gauge 4 are not limited to being connected to an independent control host 5. They can also be directly connected to existing distributed control systems, programmable logic controllers, or industrial computers in the factory. Alternatively, the level signal and thickness measurement signal can be converted into standard industrial signals by a signal converter and then connected to the aforementioned control equipment.

[0057] Specifically, the output terminals of cables 36 of the level gauge 3 and each thickness gauge 4 can be connected to a signal converter. The signal converter converts the level signal output by the level gauge 3 and the thickness measurement signal output by each thickness gauge 4 into standard industrial signals such as 4-20mA analog signals, RS485 digital signals, or HART protocol signals, which are then received and processed by the factory's existing control system. This control system presets start and stop thresholds for each thickness gauge 4, determines the triggering timing based on the level signal, and sends trigger or stop signals to each thickness gauge 4, achieving the same multi-point trigger measurement function as in the aforementioned embodiments. This connection method allows the device to seamlessly integrate into the factory's existing automation control network without requiring an additional independent control host 5, reducing system integration costs. It also allows operators to uniformly view level and wall thickness data within the existing control interface without switching operating platforms.

[0058] Workflow: S1: The system is powered on, and the level gauges enter continuous monitoring mode, outputting level signals to the control host in real time. All thickness gauges are in silent mode.

[0059] S2: The control host continuously compares the material level signal with the preset activation threshold of each thickness gauge. When the material level drops below the activation threshold of the uppermost thickness gauge and remains below it for a preset duration, the control host sends a trigger signal to that thickness gauge.

[0060] S3: The triggered thickness gauge starts working, receives gamma rays penetrating the tank wall and the wall coating, converts the optical signal into an electrical signal and transmits it to the control host. The control host calculates the thickness according to the wall coating thickness calculation formula and stores the data. After one valid measurement is completed, the thickness gauge exits operation and returns to silence.

[0061] S4: As the material level continues to drop, the control host will trigger the middle thickness gauge and the bottom thickness gauge in the same way to perform measurements and obtain the wall thickness data at the corresponding positions.

[0062] S5: When the material level rises above the exit threshold of a certain thickness gauge and remains there for a preset time, the control host sends an exit signal to the thickness gauge. The hysteresis range between the start and exit thresholds prevents frequent starts and stops caused by material level fluctuations.

[0063] S6: After completing a full unloading cycle, the control host associates the wall thickness data of each thickness gauge with the corresponding installation height position to generate the distribution information of the wall thickness along the height direction of the tank.

[0064] S7: The system returns to step one and enters the next monitoring cycle.

[0065] This invention employs a functionally separated device architecture, assigning material level monitoring and wall thickness measurement to two physically independent detectors. This allows each function to utilize its most suitable detection scheme, avoiding signal crosstalk and functional conflicts inherent in integrated designs. Simultaneously, by using the continuous material level signal output from the level gauge as the trigger source for the multi-point thickness gauge, each gauge operates only within the empty tank window below its installation position. This ensures the accuracy and validity of the measurement data and significantly reduces the ineffective operating time of the core components of the thickness gauge, extending the overall lifespan of the equipment. The system architecture is simple, low-cost, and easy to maintain, and can be widely applied to online monitoring of wall thickness in various tanks in industries such as chemical, energy, and metallurgy.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tank parameter measuring device based on gamma rays, installed on a working tank, characterized in that, include: At least two radiation sources are installed at intervals along the height direction of the working tank on one side of the outer wall of the working tank; A level gauge is installed on the outer wall of the working tank on the side opposite to the radiation source and is arranged along the height direction of the working tank. It is used to continuously monitor the material level in the working tank and output a level signal. The level gauge receives γ-rays that penetrate the tank wall and the material. The level gauge covers the range of material level changes in the tank along the height direction and outputs a continuous level signal according to the difference in the attenuation of rays between the material section and the empty tank section. At least two thickness gauges are installed at intervals along the height direction of the working tank on one side of the outer wall of the working tank, and are located on the same side as the level gauge; The control host is electrically connected to the level gauge and each thickness gauge respectively; The installation height of each thickness gauge corresponds to the installation height of one of the radiation sources, such that the thickness gauge and the radiation source are symmetrical in the radial direction of the working tank, forming an independent through-beam measurement optical path; The control host presets a start threshold and an exit threshold for each thickness gauge. The start threshold is lower than the exit threshold, and the two form a hysteresis interval. The control host receives the material level signal. After the material level drops below the activation threshold of the uppermost thickness gauge and remains below the preset time, it triggers the thickness gauge to perform wall thickness measurement. At this time, the tank wall section corresponding to the thickness gauge is completely exposed to the empty tank environment without material interference. The thickness gauge receives γ rays that penetrate the tank wall and wall layer of the working tank and transmits them to the control host. The γ rays do not pass through the material layer. The formula for calculating the wall thickness is: Where λ is the source decay constant, t is the source decay time, and l x The intensity of the radiation after passing through the tank wall and the wall-mounted layer is l, the intensity of the radiation before entering the tank wall and the wall-mounted layer at the time of calibration is μ, the mass absorption coefficient of the tank wall and the wall-mounted layer for the radiation is ρ, and the density of the wall-mounted layer is ρ. As the material level continues to drop, the control host will trigger the remaining thickness gauges in the same manner to perform measurements and obtain the wall thickness data at the corresponding positions. When material is refilled, and the material level rises above the exit threshold of a certain thickness gauge and remains there for a preset time, the control host controls the thickness gauge to exit the measurement. After a complete unloading cycle is completed, the control host associates the wall thickness data of each thickness gauge with the corresponding installation height position to generate the distribution information of the wall thickness along the height direction of the tank.

2. The apparatus according to claim 1, characterized in that, Each of the radiation sources is fixed inside a shielded source container, which is installed on the outer wall of the working container. The shielded source container is provided with a collimation hole for directing the γ-ray beam emitted by the radiation source to the corresponding thickness gauge.

3. The apparatus according to claim 1, characterized in that, Each of the level gauges and each of the thickness gauges includes a crystal sensor, a photomultiplier tube, a high-voltage module, a preamplifier circuit, a cable, and a housing encapsulating the above components; the crystal sensor of the level gauge is made of PVT material and extends along the height direction, and the crystal sensor of the thickness gauge is made of NaI material.

4. The apparatus according to claim 3, characterized in that, In the level gauge and each of the thickness gauges, the photomultiplier tubes are optically coupled to the corresponding crystal sensor, and the high-voltage module and the preamplifier circuit are electrically connected to the photomultiplier tubes respectively.

5. The apparatus according to claim 1, characterized in that, The installation height of all the thickness gauges shall not exceed the detection range of the level gauge along the height direction.

6. The apparatus according to claim 1, characterized in that, The control host includes: The signal input interface is electrically connected to the level gauge and each of the thickness gauges. The control output interface is electrically connected to each of the thickness gauges and is used to send trigger signals or exit signals to each of the thickness gauges respectively.

7. A method for measuring tank parameters based on gamma rays, applied to the apparatus described in any one of claims 1 to 6, characterized in that, Includes the following steps: The level gauge continuously monitors the material level inside the working tank and outputs a level signal to the control host. According to the material level signal, after the material level drops below the activation threshold of one of the thickness gauges and continues for a preset time, the control host triggers the corresponding thickness gauge to perform wall thickness measurement. At this time, the tank wall section corresponding to the thickness gauge is completely exposed to the empty tank environment and there is no material interference. The triggered thickness gauge receives gamma rays that penetrate the tank wall and the wall coating layer of the working tank. The gamma rays do not pass through the material layer. The optical signal is converted into an electrical signal and transmitted to the control host, which then calculates the wall coating thickness.

8. The method according to claim 7, characterized in that, The control host controls the triggered thickness gauge to perform a valid measurement and then exits the operation; or, controls the triggered thickness gauge to continue performing measurements until an exit signal is received.

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