Passive nuclear level gauge measurement range or measurement distance determination system, determination method, and level measurement method

Abstract

This invention discloses a system, method, and method for determining the measurement range or distance of a passive nuclear level gauge. The system is used to determine the measurement range of the passive nuclear level gauge at a fixed position relative to the measured container or the measurement distance of the passive nuclear level gauge to a reference material. The system includes a passive nuclear level gauge, a material type identification and correction device, and a calculation and control module. The material type identification and correction device is configured to detect the nuclear radiation characteristic data released by the material in the measured container. In response to the nuclear radiation characteristic data of the material output by the material type identification and correction device meeting the conditions, the calculation and control module calculates the measurement range or measurement distance according to a preset algorithm; or the calculation and control module controls a third-party device to perform measurement to obtain the measurement range or measurement distance; or the calculation and control module determines the measurement range or measurement distance corresponding to the nuclear radiation characteristic data by querying a preset mapping relationship.

Description

Technical Field

[0001] This invention relates to the field of non-contact level measurement, and in particular to a system, method, and method for determining the measurement range or distance of a passive nuclear level gauge. Background Technology

[0002] Passive nuclear level gauges are primarily used to measure the gamma rays released by radioactive substances contained in fly ash from thermal power plants or dust collectors in metallurgical steel plants, thus measuring the material level within containers. Because passive nuclear level gauges are completely non-contact in measurement, and especially suitable for continuous monitoring of material levels within containers, they are widely used in thermal power plants and other industrial settings such as steel mills.

[0003] Since passive nuclear level gauges measure the radioactive content of materials, and as is well known, the radioactive content in materials is not constant but changes frequently, to ensure the accuracy of passive nuclear level gauge measurements, it is necessary to use external material identification equipment to identify changes in the characteristics of radioactive content in the material in real time and make corrections to ensure measurement accuracy. Alternatively, a system composed of multiple passive nuclear level gauges with multiple probes can be used to perform self-correction for changes in material type under certain conditions, thus ensuring the accuracy of the level measurement to a certain extent.

[0004] Because of variations in the radioactive characteristics of materials, the same material will release different amounts of nuclear radiation under different material conditions. Similarly, the measurement range of a passive nuclear level gauge will also differ for the same material.

[0005] For passive nuclear level gauges used for fixed-position measurements, the maximum detection radius or detection distance is completely different when measuring materials with different radioactive characteristics within the same container.

[0006] Passive nuclear level gauges have different measurement ranges for the same material, or even within the same container, the maximum detection radius or detection distance is completely different when measuring materials with different radioactive characteristics. This important issue has not been addressed by existing technologies, nor has a method been found to calculate or express the measurement range of passive nuclear level gauges. For example, the Chinese invention patent application with publication number CN119223400A describes that "for different types of materials, the detection range of the non-radioactive nuclear radiation level gauge corresponding to the minimum level scale is different, that is, R is different for different types of materials. However, since the nuclear radiation of the material attenuates according to the inverse square law when it propagates in space, the detection range R of different types of materials is relatively close when the values ​​are similar. In order to facilitate calculation, the application itself presets that R is the same for different types of materials." Even if the changes in the radioactive characteristics of the material are recognized, the only solution is to fix the measurement range to be the same for different materials with different radioactive characteristics to deal with the measurement range problem.

[0007] Existing technologies, particularly those based on relative parameters, fail to consider the measurement range of passive nuclear level gauges during operation. They also neglect changes in the actual range due to variations in coal type, and fail to provide real-time display of the gauge's measured range in practical applications. This often creates a serious misconception for operators: that material levels are measured from the zero point of the container. In reality, many passive nuclear level gauges output analog signals, and users often assign a fixed value to 4mA, such as 0 or 0%. Even with material type identification and correction devices, the internal algorithm of existing passive nuclear level gauges still calculates the material level from the zero point.

[0008] Current relative level algorithms for passive nuclear level gauges do not consider the measurement inaccuracies caused by variations in the radioactivity characteristics of the material. They assume that the actual range of a passive nuclear level gauge is the same regardless of the material's radioactivity characteristics. When the material's radioactivity characteristics deviate significantly, the level accuracy becomes extremely poor.

[0009] Under current technology, passive nuclear level gauges or their associated equipment do not provide operators with real-time information on the gauge's detection range. With the radioactivity characteristics of materials constantly changing, operators cannot accurately determine the real-time detection range of the passive nuclear level gauge under different material conditions. This can easily lead to the misinterpretation of a zero level as a truly empty chamber, rather than the material being outside the gauge's detection range. Current technology causes misjudgments and confusion for operators.

[0010] Existing technologies lack methods for measuring the range of passive nuclear level gauges. Passive nuclear level gauges cannot automatically determine the measurement range, and existing technologies have obvious shortcomings.

[0011] The above background information is provided only to aid in understanding the concept and technical solution of this application. It does not necessarily belong to the prior art of this application, nor does it necessarily provide technical guidance. In the absence of clear evidence that the above information was disclosed before the filing date of this application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0012] The purpose of this invention is to provide a system that can automatically determine the real-time measurement range of a passive nuclear level gauge or the real-time detection distance of a reference material during actual operation; completely solve the problem that existing manual fixed range settings cannot meet the inaccurate requirements of material level changes in real time and random variations in the process flow; solve the problem of missing real-time measurement range in existing passive nuclear level gauge applications; solve the problem of inaccurate material level readings generated by passive nuclear level gauges due to fixed measurement range settings; and better ensure production safety by displaying the measurement range of the passive nuclear level gauge or the detection distance for a reference material to alert users.

[0013] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0014] A system for determining the measurement range or measurement distance of a passive nuclear level gauge is provided for determining the measurement range of the passive nuclear level gauge at a fixed position relative to the container being measured or the measurement distance of the passive nuclear level gauge to a reference material. The system includes a passive nuclear level gauge, a material type identification and correction device, and a calculation and control module, wherein the material type identification and correction device and the passive nuclear level gauge are respectively communicatively connected to the calculation and control module.

[0015] The material type identification and correction instrument is configured to detect the nuclear radiation characteristic data released by the material inside the measured container;

[0016] In response to a preset triggering condition, the calculation control module is configured to perform at least one of the following operations:

[0017] The calculation and control module calculates the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material according to a preset algorithm;

[0018] The calculation and control module controls a third-party device to perform a measurement to obtain the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material;

[0019] The calculation and control module determines the measurement range of the passive nuclear level gauge corresponding to the nuclear radiation characteristic data, or the measurement distance of the passive nuclear level gauge to the reference material, by querying a preset mapping relationship.

[0020] Furthermore, based on any one or a combination of the aforementioned technical solutions, the preset triggering condition includes at least one of the following:

[0021] Received external signal;

[0022] After a preset timeout period;

[0023] Arrive at the preset time;

[0024] The passive nuclear level gauge connection signal was received;

[0025] The material type identification and correction instrument outputs material nuclear radiation characteristic data;

[0026] The nuclear radiation characteristic data output by the material type identification and correction instrument at least twice exceeds the preset condition;

[0027] The nuclear radiation data or level value measured by the passive nuclear level gauge is higher than a preset threshold.

[0028] The measurement results of the passive nuclear level gauge indicate that the radiation attenuation of the stockpile has reached a preset level;

[0029] Based on pre-stored historical data changes or process flow patterns, determine the critical time point at which the predicted material level change will be reached.

[0030] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation control module calculates the measurement range of the passive nuclear level gauge at a fixed position relative to the measured container using a preset first algorithm, including:

[0031] A nuclear radiation field formula is constructed based on nuclear radiation characteristic data, measurement layout geometric parameters, material height inside the container, and the limiting radiation value corresponding to the passive nuclear level gauge's measurement range. The limiting radiation value corresponding to the passive nuclear level gauge's measurement range is the nuclear radiation data obtained by the passive nuclear level gauge at the distance corresponding to its measurement range. The measurement layout geometric parameters include the geometric data of the container being measured and the installation position parameters of the passive nuclear level gauge relative to the container. The measurement range of the passive nuclear level gauge is the relative value between the installation position and the material inside the container, or the material height inside the container.

[0032] The measurement range of the passive nuclear level gauge at a fixed position relative to the measured container is calculated based on the nuclear radiation field formula.

[0033] Furthermore, based on any one or a combination of the aforementioned technical solutions, and assuming the measured container is a cylindrical structure, the nuclear radiation field formula in the first algorithm is:

[0034]

[0035] in, I ( H , r , h () represents the limiting radiation value corresponding to the passive nuclear level metering range. β For nuclear radiation characteristic data, h The height of the material inside the container. r Let be the radius of the base of the cylindrical container. H The value is the height difference between the installation location of the level gauge and the height of the material inside the container. μ The radiation attenuation coefficient of the material inside the container being measured is denoted as . sec It is the secant function in trigonometric functions. csc The cosecant function is a trigonometric function, and the installation position parameter of the passive nuclear level gauge relative to the measured container is defined as follows: H sum and satisfy H sum = h + H The measurement range of the passive nuclear level gauge is defined as the height of the material inside the container. h Or it could be the height difference between the installation location of the level gauge and the material height inside the container. H ;

[0036] A lateral projection is made onto the container being measured, with the vertical axis where the level gauge is located as the center axis of the projection. The installation position of the level gauge is defined as point O. The lower endpoints of the rectangular projection of the material inside the container are points A and B, one of the upper endpoints is point C, and the movable point on the projection edge contour is point X. θ 1 is defined as half the angle between rays OA and OB. θ 2 is defined as the angle between ray OC and the vertical axis containing point O. θ It is defined as the angle between ray OX and the vertical axis containing point O.

[0037] Furthermore, based on any one or a combination of the aforementioned technical solutions, the nuclear radiation characteristic data are calculated using the following formula:

[0038] β = κcρ / μ ,in, κ The radiation constant, c The content of radioactive material inside the container being measured. ρ The bulk density of the radioactive material inside the container being measured. μ The radiation attenuation coefficient of the material inside the container being measured.

[0039] Furthermore, following any one or a combination of the aforementioned technical solutions, the detection position height of the material type identification and correction instrument is set to the installation height of the level gauge. I ( H , r , h This refers to the real-time nuclear radiation data detected by the passive nuclear level gauge.

[0040] The installation height of the level gauge relative to the container being measured is pre-measured. H sum ;

[0041] Will h = H sum - H Substituting the values ​​into the nuclear radiation field formula, the height difference between the installation location of the level gauge and the material height inside the container being measured is calculated. H As a real-time level gauge measurement range; or, to... H = H sum - h Substituting the nuclear radiation field formula, the height of the material inside the container is calculated. h , as a real-time level gauge measurement range.

[0042] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using a preset second algorithm, including:

[0043] Preset reference materials;

[0044] The maximum detection distance of the passive nuclear level gauge for the reference material is pre-calculated or measured.

[0045] Real-time relative material type values ​​between the baseline material and the reference material;

[0046] Based on the relationship function between the passive nuclear level gauge's measurement distance to the reference material, the maximum detection distance of the reference material, and the real-time relative material type value, the measurement distance of the passive nuclear level gauge to the reference material is calculated. The real-time relative material type value is defined as the ratio of the nuclear radiation characteristic data of the real-time reference material detected by the material type identification and correction instrument to the nuclear radiation characteristic data of the reference material.

[0047] Furthermore, based on any one or a combination of the aforementioned technical solutions, the relationship function between the passive nuclear level gauge's measurement distance to the real-time reference material, the maximum detection distance of the reference material, and the relative material type value is constructed as follows:

[0048] R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the real-time reference material. R 1 represents the maximum detection distance of the reference material obtained through pre-measurement or calculation; P This represents the real-time relative material type value between the real-time baseline material and the reference material.

[0049] Furthermore, based on any one or a combination of the aforementioned technical solutions, the real-time relative material type value P Obtain it through the following methods:

[0050] Real-time reference material and reference material of the same height, volume or weight were placed in the same first dedicated metering tank. The nuclear radiation characteristic data of the real-time reference material were measured using the same material type identification and correction instrument. C 2. Nuclear radiation characteristic data of reference materials C 1;

[0051] Calculate the relative planting material using the formula. P = C 2 / C 1.

[0052] Furthermore, based on any one or a combination of the aforementioned technical solutions, the nuclear radiation characteristic data of the reference material... C 1 and the maximum detection distance of the reference material R 1 is stored as a calibration parameter;

[0053] The system also includes a second dedicated metering tank, which is controllably connected to the container being measured; in response to the calculation and control module's requirement to calculate the measurement distance of the passive nuclear level gauge to the reference material, material with the same height, volume or weight as the reference material is extracted from the container being measured as the real-time reference material and discharged into the second dedicated metering tank;

[0054] The second dedicated metering vessel is also equipped with a device configured to detect the nuclear radiation signature data released by the real-time reference material inside the second dedicated metering vessel. C 2. Material type identification and correction instrument.

[0055] Furthermore, following any one or a combination of the aforementioned technical solutions, the maximum detection distance of the reference material is measured in the following manner:

[0056] The passive nuclear level gauge was used to measure the nuclear radiation data of a reference material.

[0057] Move the passive nuclear level gauge to find the extreme position where its nuclear radiation measurement result changes abruptly;

[0058] The closest distance from the extreme position to the reference material is measured and used as the maximum detection distance of the reference material.

[0059] Furthermore, based on any one or a combination of the aforementioned technical solutions, the maximum detection distance of the reference material is calculated in the following manner:

[0060] Determine the current detection distance between the passive nuclear level gauge and the reference material. R 11 ;

[0061] Detecting the nuclear radiation data released by the reference material I 11 ;

[0062] The maximum detection distance of the reference material is calculated using the following formula. R 1: R 1= R 11 × ,in, I 1 represents the limiting radiation value corresponding to the passive nuclear material level metering range.

[0063] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material through a fitting function.

[0064] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement range of the passive nuclear level gauge using a fitting function, which is given by the following formula:

[0065] L = a n ×q n + a n-1 ×q n-1 +...+ a 1×q+ a 0, where, L The measurement range is given by q, where q represents the nuclear radiation characteristic data of the material being measured. a 0 to a n For polynomial coefficients, a n ≠0,n ≥2;

[0066] Alternatively, the calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using a fitting function, which is given by the following formula:

[0067] L =(1 / μ )× ln ([q×V×) A ] / I )+ D ,in, L q represents the measurement distance of the passive nuclear level gauge to the reference material, q represents the nuclear radiation characteristic data of the material to be measured, and V represents the quantity data of the reference material. I This represents the limiting radiation value corresponding to the passive nuclear level metering range. μ The linear attenuation coefficient is... A These are calibration coefficients used to correct the deviation between the theoretical model and the actual measurement system. D This is a correction constant used to compensate for errors;

[0068] Alternatively, the calculation and control module calculates the maximum detection distance of the passive nuclear level gauge to the reference material using a fitting function, and calculates the measurement distance of the passive nuclear level gauge to the reference material using the following formula: R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the reference material. P This refers to the real-time relative material type values ​​between the real-time baseline material and the reference material. R 1 represents the maximum detection distance of the reference material, where the fitting function for calculating the maximum detection distance of the reference material is any of the following formulas:

[0069] R 1 = b n ×V n + b n-1 ×V n-1 +...+ b 1×V+ b 0, where R 1 represents the maximum detection distance of the level gauge for the reference material, and V represents the quantity of the reference material. b 0 to b n For polynomial coefficients, b n ≠0, n ≥2; or, R 1 = c n ×H ref n + c n-1 × H ref n-1 +...+ c 1× H ref + c 0, where, R 1. Maximum detection distance for reference materials H ref For reference material height data, c 0 to c n For polynomial coefficients, c n ≠0, n ≥2.

[0070] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement range of the passive nuclear level gauge using a preset fitting function, including:

[0071] Construct a fitting function between the measurement range of a passive nuclear level gauge at a fixed position in the container being measured and the nuclear radiation characteristic data of the material being measured;

[0072] The material is subjected to a measurement test in the container being measured to obtain test data including the measurement range and nuclear radiation characteristic data.

[0073] Based on the experimental data, determine the coefficients in the fitting function;

[0074] The material type identification and correction instrument is used to detect the nuclear radiation characteristic data of the material to be tested, and the corresponding measurement range is obtained by substituting it into the fitting function after determining the coefficients.

[0075] Furthermore, following any one or a combination of the aforementioned technical solutions, the fitting function between the measurement range and the nuclear radiation characteristic data is a high-order polynomial:

[0076] L = a n ×q n + a n-1 ×q n-1 +...+ a 1×q+ a 0, where, L The measurement range is given by q, where q represents the nuclear radiation characteristic data of the material being measured. a n ≠0, n ≥2;

[0077] Based on the experiment, experimental data were obtained for multiple sets of correlated measurement ranges and nuclear radiation characteristic data;

[0078] Data fitting is performed on the higher-order polynomial to determine the polynomial coefficients. a 0 to a n .

[0079] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using the following formula: R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the reference material. P This refers to the real-time relative material type values ​​between the real-time baseline material and the reference material. R 1 represents the maximum detection distance of the reference material, which is obtained in the following way:

[0080] The calculation and control module calculates the maximum detection distance of the passive nuclear level gauge for the reference material using a preset fitting function, including:

[0081] Construct a fitting function between the maximum detection distance of the passive nuclear level gauge for reference material and the quantity data of the reference material, wherein the quantity data of the reference material is one or more of height, volume, and weight;

[0082] The material is measured and tested to obtain multiple sets of related test data, including the maximum detection distance and the quantity of the reference material.

[0083] Based on the experimental data, determine the coefficients in the fitting function;

[0084] Obtain the quantity data of the current reference material, and substitute it into the fitting function after determining the coefficients to obtain the corresponding maximum detection distance for the reference material.

[0085] Furthermore, based on any one or a combination of the aforementioned technical solutions, the fitting function between the maximum detection distance of the level gauge for the reference material and the quantity data of the reference material is a high-order polynomial:

[0086] R 1 = b n ×V n + b n-1 ×V n-1 +...+ b 1×V+ b 0, where R1 represents the maximum detection distance of the level gauge for the reference material, and V represents the quantity of the reference material. b n ≠0, n ≥2;

[0087] Based on the experiment, multiple sets of associated maximum detection distance and quantity data of reference materials were obtained;

[0088] Data fitting is performed on the higher-order polynomial to determine the polynomial coefficients. b 0 to b n .

[0089] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement distance of the passive nuclear level gauge at a fixed position in the measured container to the reference material using the following formula: R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the reference material. P This refers to the real-time relative material type values ​​between the real-time baseline material and the reference material. R 1 represents the maximum detection distance of the reference material, which is obtained in the following way:

[0090] The calculation and control module calculates the maximum detection distance of the passive nuclear level gauge to the reference material in the measured container using a preset fitting function, including:

[0091] Construct a fitting function between the maximum detection distance of the passive nuclear level gauge to the reference material and the height data of the reference material;

[0092] The material was measured and tested to obtain test data including the maximum detection distance and the height of the reference material;

[0093] Based on the experimental data, determine the coefficients in the fitting function;

[0094] The height of the reference material in the fitted function after determining the coefficients is replaced with the difference between the installation height of the passive nuclear level gauge and the maximum detection distance to obtain a new function;

[0095] By substituting the current installation height of the passive nuclear level gauge into the new function, the maximum detection distance of the corresponding reference material is calculated.

[0096] Furthermore, based on any one or a combination of the aforementioned technical solutions, the fitting function between the maximum detection distance of the passive nuclear level gauge for the reference material and the height data of the reference material is a high-order polynomial:

[0097] R 1 = c n × H ref n + c n-1 × H ref n-1 +...+ c 1× H ref + c 0, where, R 1. Maximum detection distance for reference materials H ref For reference material height data, c n ≠0, n ≥2;

[0098] Based on the experiment, multiple sets of related experimental data were obtained, including the maximum detection distance and height of the reference material.

[0099] Data fitting is performed on the higher-order polynomial to determine the polynomial coefficients. c 0 to c n ;

[0100] Define the installation height of the passive nuclear level gauge relative to the fixed position of the container being measured as . H sum ,based on H ref = H sum - R 1. A new function is obtained as the function for calculating the maximum detection distance of the reference material: R 1 = c n ×( H sum - R 1) n + c n-1 ×( H sum - R 1) n-1 +...+ c 1×( H sum - R 1)+ c 0.

[0101] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using the following formula:R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the reference material. P This refers to the real-time relative material type values ​​between the real-time baseline material and the reference material. R 1 represents the maximum detection distance of the reference material, which is obtained in the following way:

[0102] The fitting function between the maximum detection distance of the passive nuclear level gauge to the reference material and the height data of the reference material is constructed as follows: R 1 = c n × H ref n + c n-1 × H ref n-1 +...+ c 1× H ref + c 0, where, R 1 represents the maximum detection distance for the reference material. H ref For reference material height data, c n ≠0, n ≥2;

[0103] The material was measured and tested to obtain test data including the maximum detection distance and the height of the reference material;

[0104] Based on the experimental data, determine the coefficients in the fitting function. c 0 to c n ;

[0105] Obtain the height data of the current reference material, and substitute it into the fitting function after determining the coefficients to obtain the maximum detection distance of the reference material.

[0106] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using a preset fitting function, including:

[0107] Construct a fitting function between the measurement distance of the passive nuclear level gauge to the reference material, the quantity data of the reference material, and the nuclear radiation characteristic data, wherein the quantity data of the reference material is one or more of height, volume, and weight;

[0108] Measurement tests were conducted on the reference material to obtain test data including the measurement distance of the passive nuclear level gauge to the reference material, the quantity data of the reference material, and the nuclear radiation characteristic data;

[0109] Based on the experimental data, determine the coefficients in the fitting function;

[0110] The material type identification and correction instrument is used to detect the nuclear radiation characteristic data of the material to be tested, the quantity data value of the reference material is selected, and the fitting function after determining the coefficients is substituted to obtain the corresponding measurement distance.

[0111] Furthermore, based on any one or a combination of the aforementioned technical solutions, the fitting function is the following polynomial:

[0112] L =(1 / μ )× ln ([q×V×) A ] / I )+ D ,in, L q represents the measurement distance of the passive nuclear level gauge to the reference material, q represents the nuclear radiation characteristic data of the material to be measured, and V represents the quantity data of the reference material. I This represents the limiting radiation value corresponding to the passive nuclear level metering range. μ The linear attenuation coefficient is... A These are calibration coefficients used to correct the deviation between the theoretical model and the actual measurement system. D This is a correction constant used to compensate for errors;

[0113] Based on the experiment, multiple sets of associated measured distances were obtained. L Reference material quantity data V, nuclear radiation characteristic data q;

[0114] Based on the experimental data, the linear decay coefficient in the fitted function was determined. μ、 Correction constant D and calibration coefficient A .

[0115] Furthermore, following any one or a combination of the aforementioned technical solutions, the passive nuclear level gauge used to measure the reference material is replaced by other types of nuclear radiation measuring equipment, wherein the nuclear radiation measuring equipment has the same nuclear radiation detection performance as the passive nuclear level gauge, or the nuclear radiation detection performance of the nuclear radiation measuring equipment is derived from the nuclear radiation detection performance of the passive nuclear level gauge.

[0116] Furthermore, following any one or a combination of the aforementioned technical solutions, the container to be measured in the experiment is served by another container, which has the same structure as the container to be measured, or the structure of the other container is a proportionally enlarged or reduced version of the container to be measured.

[0117] Furthermore, in accordance with any or a combination of the aforementioned technical solutions, the system further includes the third-party device that is triggered by the computing control module to perform the measurement steps, which includes a material level detection device, a track whose positional relationship with the measured container is determined, and a nuclear radiation sensor that can be driven to move on the track.

[0118] Based on the actual height of the material in the container being measured provided by the material level detection device and the nuclear radiation sensor moving to the critical position where the detection data becomes zero, the measurement range of the nuclear radiation sensor is obtained.

[0119] Based on the range conversion relationship between the nuclear radiation sensor and the passive nuclear level gauge, the measurement range of the passive nuclear level gauge is obtained.

[0120] Furthermore, based on any or a combination of the aforementioned technical solutions, the material level detection device includes a visual recognition device, a radar device, an ultrasonic device, a weighing device, or a touch switch that can move downward relative to the container being measured.

[0121] Furthermore, following any one or a combination of the aforementioned technical solutions, the calculation control module is integrated into the material type identification and correction instrument; or, the calculation control module is integrated into the passive nuclear level gauge; or, the calculation control module is an external device that is wired or wirelessly connected to the material type identification and correction instrument.

[0122] Furthermore, following any one or a combination of the aforementioned technical solutions, the function of the calculation control module is implemented by the computational processing unit of the material type identification and correction instrument, or by the computational processing unit of the passive nuclear level gauge.

[0123] Furthermore, in accordance with any or a combination of the aforementioned technical solutions, the passive nuclear level gauge measurement range or measurement distance determination system provided by the present invention further includes a display device and / or an output module, wherein the display device is configured to display the current measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material, and / or to display the level measurement result of the passive nuclear level gauge;

[0124] The output module is configured to send the measurement range and / or material level measurement results to a remote client via wired and / or wireless output.

[0125] Furthermore, based on any or a combination of the aforementioned technical solutions, the display device is integrated with one of the passive nuclear level gauge, the material type identification and correction device, and the calculation and control module; or, the display device is wired or wirelessly connected to the passive nuclear level gauge, the material type identification and correction device, and / or the calculation and control module.

[0126] Furthermore, following any of the aforementioned technical solutions or combinations thereof, if the level value generated by the passive nuclear level gauge is less than or equal to a preset level threshold, or the nuclear radiation data measured by the passive nuclear level gauge is less than or equal to a preset nuclear radiation threshold, then the passive nuclear level gauge outputs a prompt message in a preset format, the prompt message including the current measurement range information.

[0127] According to another aspect of the present invention, a method for determining the measurement range or measurement distance of a passive nuclear level gauge is provided, comprising the following steps: determining the measurement range of the passive nuclear level gauge at a fixed position relative to the container being measured or the measurement distance of the passive nuclear level gauge to a reference material.

[0128] The nuclear radiation characteristics data released by the material inside the measured container were detected using a material type identification and correction instrument.

[0129] In response to a preset trigger condition, perform one of the following operations:

[0130] The measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material is calculated according to the preset algorithm.

[0131] Alternatively, control a third-party device to perform measurements to obtain the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material;

[0132] Alternatively, by querying a preset mapping relationship, the measurement range of the passive nuclear level gauge corresponding to the nuclear radiation characteristic data, or the measurement distance of the passive nuclear level gauge to the reference material corresponding to the nuclear radiation characteristic data, can be determined.

[0133] Furthermore, following any one or a combination of the aforementioned technical solutions, the preset algorithm is any one of the following first algorithm, second algorithm, third algorithm, and fourth algorithm:

[0134] The first algorithm is to construct a nuclear radiation field formula based on nuclear radiation characteristic data, measurement layout geometric parameters, material height inside the container, and the limiting radiation value corresponding to the passive nuclear level gauge's measurement range. The limiting radiation value corresponding to the passive nuclear level gauge's measurement range is the nuclear radiation data obtained by the passive nuclear level gauge at the distance corresponding to its measurement range. The measurement layout geometric parameters include the geometric data of the container being measured and the installation position parameters of the passive nuclear level gauge relative to the container. The measurement range of the passive nuclear level gauge is [value missing]. The algorithm also determines the relative value between the installation position and the material inside the container being measured, or the material height inside the container being measured is equal to the measurement range of the level gauge.

[0135] The second algorithm is to prepare a reference material; pre-calculate or measure the maximum detection distance of the reference material and the real-time relative material type value between the reference material and the benchmark material; construct a relationship function between the measurement distance of the passive nuclear level gauge to the benchmark material, the maximum detection distance of the reference material, and the real-time relative material type value, wherein the real-time relative material type value is defined as the ratio of the nuclear radiation characteristic data of the real-time benchmark material detected by the material type identification and correction instrument to the nuclear radiation characteristic data of the reference material;

[0136] The third algorithm involves constructing a fitting function between the measurement range of the passive nuclear level gauge at a fixed position in the measured container and the nuclear radiation characteristic data of the material to be measured; or constructing a fitting function between the measurement distance of the passive nuclear level gauge to the reference material and the quantity data of the reference material; or constructing a fitting function between the measurement distance of the passive nuclear level gauge to the reference material, the quantity data of the reference material, and the nuclear radiation characteristic data; performing measurement experiments on the material and determining the coefficients in the fitting function based on the experimental data; and using the fitting function after determining the coefficients to calculate the corresponding measurement range of the level gauge or the measurement distance of the level gauge to the reference material.

[0137] The fourth algorithm involves constructing a fitting function between the maximum detection distance of the passive nuclear level gauge to the reference material and the quantity data of the reference material; conducting measurement experiments on the material and determining the coefficients in the fitting function based on the experimental data; using the fitting function with determined coefficients to calculate the maximum detection distance of the passive nuclear level gauge to the reference material; and using a formula to calculate the measurement distance of the passive nuclear level gauge to the reference material. R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the reference material. P This refers to the real-time relative material type values ​​between the real-time baseline material and the reference material. R 1 represents the maximum detection distance of the reference material.

[0138] Furthermore, in accordance with any or a combination of the aforementioned technical solutions, the reference material may be either material outside the measuring range edge or material within the measuring range.

[0139] When the passive nuclear level gauge on the calculation container is installed from the bottom of the container to when it is filled with material, or when the installation position of the passive nuclear level gauge is within the upward measuring range or measuring distance of the passive nuclear level gauge, the medium in the measuring space is material.

[0140] According to another aspect of the present invention, a method for measuring the level of a passive nuclear level gauge is provided, comprising the following steps:

[0141] After determining the current measurement range of the passive nuclear level gauge using the measurement range or measurement distance determination system described above, the method further includes the step of the passive nuclear level gauge calculating the level height of the material entering the measurement range using the current measurement range:

[0142] Based on the difference between the measured value of the passive nuclear level gauge and the preset empty container value, the difference between the real-time full container value and the preset empty container value, and the measurement range, the relative material level value within the measurement range is calculated. The relative material level value is the material level value measured from the edge of the measurement range within the measurement range of the passive nuclear level gauge.

[0143] If the difference between the relative installation height of the passive nuclear level gauge and the measurement range is greater than or equal to 0, then the sum of the relative level value and the difference between the relative installation height of the passive nuclear level gauge and the measurement range is calculated to obtain the level value of the material in the container.

[0144] The beneficial effects of the technical solution provided by this invention are as follows:

[0145] a. Solve the problem that the real-time range cannot be automatically generated / determined in the application of existing passive nuclear level gauges;

[0146] b. Solve the problem that the detection range of passive nuclear level gauges cannot be known after changes in material type;

[0147] c. It can indicate the actual real-time range of the passive nuclear level gauge to the operators, enabling them to take more reasonable operating measures and ensure production safety;

[0148] d. Based on real-time range data, the problem of inaccurate relative material level in passive nuclear level gauges can be solved, resulting in more accurate material level readings;

[0149] e. This application essentially provides a method for calculating the actual measurement range of a passive nuclear level gauge on a container, which more clearly explains the problem of measuring the range or measuring the distance to a reference material in practical applications of passive nuclear level gauges, and solves the problem of inaccurate range positioning or lack of standardized expression in the prior art. Attached Figure Description

[0150] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0151] Figure 1 A schematic diagram of a first passive nuclear level gauge measurement range or measurement distance determination system provided as an exemplary embodiment of the present invention;

[0152] Figure 2 A schematic diagram of a second passive nuclear level gauge measurement range or measurement distance determination system provided as an exemplary embodiment of the present invention;

[0153] Figure 3 A schematic diagram illustrating the process of a computational control module for an exemplary embodiment of the present invention calculating the measurement range of a passive nuclear level gauge at a fixed position relative to the container being measured using a first algorithm.

[0154] Figure 4 A schematic diagram of the layout for measuring geometric parameters provided as an exemplary embodiment of the present invention;

[0155] Figure 5 A schematic diagram illustrating how a calculation control module, provided as an exemplary embodiment of the present invention, calculates the measurement distance of a passive nuclear level gauge relative to a fixed position of the measured container to a reference material using a second algorithm;

[0156] Figure 6 A flowchart illustrating the process of obtaining the maximum detection distance of a reference material by measurement, as provided in an exemplary embodiment of the present invention;

[0157] Figure 7 A flowchart illustrating the calculation of the maximum detection distance of a reference material, provided as an exemplary embodiment of the present invention;

[0158] Figure 8 A flowchart illustrating a first method for determining the measurement range or measurement distance of a passive nuclear level gauge, provided as an exemplary embodiment of the present invention;

[0159] Figure 9A flowchart illustrating a second method for determining the measurement range or measurement distance of a passive nuclear level gauge, provided as an exemplary embodiment of the present invention;

[0160] Figure 10 This is a schematic flowchart of a passive nuclear level gauge level measurement method provided as an exemplary embodiment of the present invention. Detailed Implementation

[0161] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0162] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0163] In one embodiment of the present invention, a system for determining the measurement range or measurement distance of a passive nuclear level gauge is provided, such as... Figure 1 As shown, the system includes a passive nuclear level gauge, a material type identification and correction device, and a calculation and control module. The material type identification and correction device and the passive nuclear level gauge are respectively connected to the calculation and control module. The material type identification and correction device is configured to detect the nuclear radiation characteristic data released by the material in the measured container.

[0164] The nuclear radiation characteristic data detected by the material type identification and correction instrument are relevant physical quantities affecting the release of nuclear radiation per unit quantity or volume of material. These are typically expressed as the radiation constant, the content of radioactive material in the measured container, the bulk density, and the radiation attenuation coefficient. The material type identification and correction instrument is usually installed close to a passive nuclear level gauge. The passive nuclear level gauge can detect nuclear radiation data, and its principle for measuring the material level in a container is based on the relationship between nuclear radiation data, nuclear radiation characteristic data, and the material height within the container. In existing technologies, passive nuclear level gauges are typically assumed to have a fixed effective detection range. This application breaks with this conventional view, proposing that the measurement range of the passive nuclear level gauge is dynamically changing under different conditions. For example, changes in the type of material in the container, changes in material height, etc., are all factors that cause changes in the measurement range of the passive nuclear level gauge. The application automatically determines the real-time measurement range of the passive nuclear level gauge on the container or the measurement distance of the passive nuclear level gauge to the reference material in the application of the passive nuclear level gauge.

[0165] Therefore, this invention proposes a system for determining the measurement range or measurement distance of a passive nuclear level gauge. The system aims to determine the measurement range of the passive nuclear level gauge at a fixed position relative to the measured container or the measurement distance of the passive nuclear level gauge to a reference material. This determination can be achieved through calculation, by looking up a mapping relationship, or by controlling a third-party device to obtain the data. The system includes a passive nuclear level gauge, a material type identification and correction device, and a calculation and control module. The material type identification and correction device and the passive nuclear level gauge are communicatively connected to the calculation and control module. The material type identification and correction device is configured to detect the nuclear radiation characteristic data released by the material within the measured container.

[0166] In response to a preset triggering condition, the calculation control module is configured to perform at least one of the following operations:

[0167] The calculation and control module calculates the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material according to a preset algorithm;

[0168] The calculation and control module controls a third-party device to perform a measurement to obtain the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material;

[0169] The calculation and control module obtains the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material by querying the correspondence between the preset nuclear radiation characteristic data and the measurement range of the passive nuclear level gauge, or the correspondence between the nuclear radiation characteristic data and the measurement distance of the passive nuclear level gauge to the reference material.

[0170] Regarding the material type identification and correction device in this application, please refer to the description of the material type radioactivity measuring device in Chinese patent application with publication number CN104482996A, and the description of the material type correction module in Chinese patent application with publication number CN119223400A. It will not be repeated in this application document.

[0171] The passive nuclear level gauge measurement range or measurement distance determination system proposed in this invention determines the range of the passive nuclear level gauge under certain conditions. In one embodiment of this invention, in response to the material type identification and correction instrument outputting material nuclear radiation characteristic data, the system determines the range of the passive nuclear level gauge. The frequency of the system determining the range depends on the detection frequency of the material type identification and correction instrument; that is, if the material type identification and correction instrument is real-time detection, the system calculates and updates the range of the level gauge in real time. In another embodiment of this invention, in response to the change in nuclear radiation characteristic data output by the material type identification and correction instrument at least twice exceeding a preset condition, the system determines the range of the passive nuclear level gauge. Compared with the former embodiment, the frequency of the system determining the range in this embodiment is lower. Specifically, it determines whether the conditions for triggering the determination action are met according to the preset conditions, such as:

[0172] The difference between two adjacent or non-adjacent detection values ​​of the material type identification and correction instrument exceeds the preset difference threshold.

[0173] Alternatively, if the ratio of two adjacent or non-adjacent detection values ​​A and B of the material type identification correction instrument exceeds the preset ratio range, the instrument will be triggered when A > 1.05 × B or A < 0.95 × B, within the preset ratio range [0.95, 1.05].

[0174] Alternatively, the material type identification correction instrument detects three (or more) adjacent or non-adjacent values ​​A, B, and C before and after the material type, satisfying that both |AB| and |BC| exceed the preset difference threshold.

[0175] Alternatively, a preset ratio range of [0.95, 1.05] is defined. The material type identification and correction instrument triggers if the following conditions are met: A > 1.05 × B and A > 1.05 × C; or A > 1.05 × B and B > 1.05 × C; or A < 0.95 × B and A < 0.95 × C; or A < 0.95 × B and B < 0.95 × C. This is not an exhaustive list. In short, this application proposes that the material level metering range is not constant and can be redefined under certain conditions.

[0176] In addition to the conditions for triggering a specific action mentioned above, there are many other preset trigger conditions in actual implementation, including any of the following:

[0177] Upon receiving external signals, such as signals input by the user through a human-machine interface, wired or wireless debugging equipment, the system of this application determines the material level measurement range or the measurement distance to the reference material. In today's intelligent industrial systems, the system of this application may also receive external signals from DCS or PLC systems, thereby determining the material level measurement range or the measurement distance to the reference material. Based on their own judgment or requirements, and based on their own data analysis, such as AI or big data analysis or operational requirements, external systems and equipment send signals to the system of this application. Upon receiving the external signals, the system of this application executes the process of determining the measurement range.

[0178] Alternatively, it can be set to a preset time interval. Typically, to ensure stable system operation, the system of this application can preset a time interval, i.e., a cycle duration, to determine the measurement range, such as determining the range data every 1 hour.

[0179] Alternatively, it can be set to reach a preset time. In addition to periodic duration presets, in practical applications, at certain critical moments, such as when a process injects material into the container measured by the passive nuclear level gauge at 9 pm, the system of this application in the process flow can be set to determine the range at 8:45 pm to ensure accurate measurement in subsequent processes.

[0180] Alternatively, the system receives a signal indicating that the passive nuclear level gauge has connected to the system. In practical implementation, especially since the system of this application is based on wireless communication, the passive nuclear level gauge may disconnect due to the instability of the wireless system. When the passive nuclear level gauge connects to the system, the system can determine the measurement range. Furthermore, when a new passive nuclear level gauge is added to the system, the system determines the measurement range after receiving the signal indicating that the passive nuclear level gauge has connected to the system.

[0181] Alternatively, the nuclear radiation data or level value measured by the passive nuclear level gauge may exceed a preset threshold. In practical applications, to avoid frequent determination of the level measurement range, the system can determine the range only after the nuclear radiation data or level value measured by the passive nuclear level gauge exceeds the preset threshold. For example, the level generated by the passive nuclear level gauge may be higher than the preset 0.5 meters, or the measured value of the passive nuclear level gauge may be greater than the preset 350.

[0182] Alternatively, the measurement results of the passive nuclear level gauge can characterize the decay of the stockpile radiation to a preset level, meaning that the nuclear radiation data measured by the passive nuclear level gauge is used to determine whether the decay correction activation condition is met. For multi-probe passive nuclear level gauges, when the passive nuclear level gauge parameter indicates that the stockpile radiation has decayed, it means that the material in the container has entered or is beginning to enter the measurement range of the high-level passive nuclear level gauge probe. At this time, it is necessary to determine the measurement range to ensure accurate measurement when the material enters the high-level probe. The applicant's Chinese patent application with publication number CN118583249B provides a detailed description of determining whether the nuclear radiation data meets the decay correction activation condition, which will not be repeated here.

[0183] Alternatively, based on historical data changes or process flow patterns, the system can predict the critical time point for material level changes. With the widespread application of AI and big data, this system can predict the point in time when significant changes in the material within the container might occur, based on historical data changes or process flow patterns. Before that significant change occurs, the system determines the material level measurement range to prepare for the impending significant level change, including more accurate measurements at critical moments. Taking reactor feeding as an example, combining historical data, it can be determined that if the system feed pump pressure is set to level A, the critical time point for predicting material level changes will be reached 3 minutes and 20 seconds after startup; if the system feed pump pressure is set to level B, the critical time point for predicting material level changes will be reached 4 minutes and 10 seconds after startup.

[0184] Based on actual needs and process characteristics, there are many preset trigger conditions, all aimed at ensuring more accurate subsequent measurements.

[0185] The measurement range in this application includes at least two definitions: one is the measurement range of the passive nuclear level gauge at a fixed position relative to the container being measured, and the other is the measurement distance of the passive nuclear level gauge to a reference material. Calculating or obtaining the measurement range of the passive nuclear level gauge at a fixed position on the container can accurately reflect the measurement boundary in a specific container application, while the measurement distance of the passive nuclear level gauge to the reference material can provide users with a reference for the measurement capability of the passive nuclear level gauge. Furthermore, the measurement boundary of the passive nuclear level gauge at a fixed position on the container can be derived to some extent through multiple reference material ranges.

[0186] The system in this application uses different generation or acquisition methods to determine the measurement range or measurement distance of the level gauge, which can be broadly divided into three types:

[0187] (i) The calculation and control module calculates the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material according to the preset algorithm;

[0188] (ii) such as Figure 2As shown, the calculation and control module controls a third-party device to perform a measurement to obtain the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material;

[0189] (iii) The calculation control module obtains the measurement range of the passive nuclear level gauge corresponding to the nuclear radiation characteristic data currently output by the material type identification correction instrument, or the measurement distance of the passive nuclear level gauge to the reference material, by querying the preset mapping relationship. The mapping relationship here refers to the correlation between nuclear radiation characteristic data and the measurement range of the passive nuclear level gauge, or the correlation between nuclear radiation characteristic data and the measurement distance of the passive nuclear level gauge to the reference material.

[0190] The specific implementation methods for generating or obtaining the range are described in detail below:

[0191] First embodiment: The calculation control module calculates the measurement range of the passive nuclear level gauge at a fixed position relative to the measured container using a preset first algorithm, such as... Figure 3 As shown, the first algorithm includes:

[0192] S110: Construct a nuclear radiation field formula based on nuclear radiation characteristic data, measurement layout geometric parameters, material height inside the container, and the limiting radiation value corresponding to the passive nuclear level gauge range. The limiting radiation value corresponding to the passive nuclear level gauge range is the nuclear radiation data obtained by the passive nuclear level gauge at the distance position corresponding to the measurement range. The measurement layout geometric parameters include the geometric data of the measured container and the installation position parameters of the passive nuclear level gauge relative to the measured container. The measurement range of the passive nuclear level gauge is the relative value between the installation position and the material inside the container, or the material height inside the container.

[0193] S120: Calculate the measurement range of the passive nuclear level gauge at a fixed position relative to the measured container based on the nuclear radiation field formula.

[0194] In a further specific embodiment, the container being measured is set to a cylindrical structure, and the corresponding nuclear radiation field formula is constructed as follows:

[0195]

[0196] in, I ( H , r , h () represents the limiting radiation value corresponding to the passive nuclear level metering range. β For nuclear radiation characteristic data, h The height of the material inside the container;

[0197] To clarify the meaning of the length and angle parameters in the above nuclear radiation field formula, a lateral virtual projection is made onto the measured container; more precisely, a projection is made onto the passive nuclear level gauge and the material inside the container, with the vertical axis where the level gauge is located as the central axis of the projection. Figure 4 As shown, the installation position of the passive nuclear level gauge is defined as point O. This level gauge can be installed on the cylindrical axis of the container being measured, at a fixed position vertically above the material, or it can be installed on the outer wall of the container. Points A and B are the lower endpoints of the rectangular projection of the material inside the container, and point C is one of the upper endpoints. θ 1 is defined as half the angle between rays OA and OB. Figure 4 ∠AOX0 in θ 2 is defined as the angle between ray OC and the vertical axis containing point O. Figure 4 In the formula, ∠COX0 sec It is the secant function in trigonometric functions. csc It is the cosecant function in trigonometric functions;

[0198] Assume the height of the material inside the container is h The radius of the base of the cylindrical container is r , H The installation position parameter of the passive nuclear level gauge relative to the measured container is defined as the height difference between the installation location of the level gauge and the material inside the container. H sum Then it satisfies H sum = h + H The measurement range of a passive nuclear level gauge is defined as the height of the material inside the container. h Or it could be the height difference between the installation location of the level gauge and the material height inside the container. H ;

[0199] A side projection is made onto the container being measured, and the moving point on the projection edge contour is designated as point X. θ Defined as the angle between ray OX and the vertical axis containing point O. Figure 4 ∠XOX0 in the middle.

[0200] In a specific embodiment of the present invention, nuclear radiation characteristic data β The calculation formula is as follows:

[0201] β = κcρ / μ ,in, κ The radiation constant, c The content of radioactive material inside the container being measured. ρ The bulk density of the radioactive material inside the container being measured. μ The radiation attenuation coefficient of the material inside the container being measured.

[0202] Set the detection position height of the material type identification and correction device to the installation height of the level gauge. I ( H , r , h This refers to the real-time nuclear radiation data detected by the passive nuclear level gauge.

[0203] It should be noted that in the formula I ( H , r , h The nuclear radiation value obtained from the measurement point in the measurement space means that the area of ​​the scintillation crystal used to collect nuclear radiation in the passive nuclear level gauge is very small. The definition of the interception area at this measurement point actually affects the accuracy of the calculation results. In practice, the interception area of ​​the scintillation crystal in the passive nuclear level gauge can vary greatly; it can be very large or very small. If the actual interception area is significantly larger than the defined area, such as 1 square centimeter, then when using the mathematical model of this embodiment, the optimal approach is to first calculate the nuclear radiation data obtained per unit area (the defined minimum interception area of ​​the measurement point) based on the interception area of ​​the scintillation crystal in the passive nuclear level gauge, and then perform the calculations described in the above embodiment of this application. For example, if the scintillation crystal's nuclear radiation interception area is 4 square centimeters, and the actual range limit nuclear radiation data measured by the passive nuclear level gauge is 20, then the range limit nuclear radiation data used for calculation should be 20 ÷ (4 ÷ 1) = 5. If the interception area of ​​the scintillation crystal detector in a passive nuclear level gauge is 1 square centimeter, then the range limit nuclear radiation value obtained by the passive nuclear level gauge can be directly used for calculation.

[0204] The installation height of the level gauge relative to the container being measured is pre-measured. H sum ;

[0205] Will h = H sum - H Substituting the values ​​into the nuclear radiation field formula, the height difference between the installation location of the level gauge and the material inside the container being measured is calculated. H As a real-time level gauge measurement range; or, to... H = H sum - h Substituting into the nuclear radiation field formula, the height of the material inside the container is calculated. h , as a real-time level gauge measurement range.

[0206] Thus, the first embodiment realizes the calculation of the measurement range of the passive nuclear level gauge at a fixed position relative to the measured container using the nuclear radiation field formula.

[0207] It should be emphasized that the calculation of the measurement range of the passive nuclear level gauge for the material inside the container at a fixed position is based on the limiting radiation value corresponding to the passive nuclear level gauge range in this embodiment. This is a key technical feature of this application, which is completely ignored by the prior art.

[0208] This embodiment describes a precise calculation method. In practical implementation, it is also necessary to consider the scenario where the material inside the container is composed of multiple materials with different radioactive characteristics, stacked like a sandwich. In such cases, a more complex calculation model based on the material's entry into the container is required to generate a more accurate measurement range. This invention does not limit the following formula to being the sole precise calculation formula:

[0209] ;

[0210] Instead, one can make variations of this function without requiring creative effort.

[0211] Second embodiment: The calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using a preset second algorithm, such as... Figure 5 As shown, it includes the following steps:

[0212] S210: Preset reference material;

[0213] S220: The maximum detection distance of the passive nuclear level gauge to the reference material is preset by calculation or measurement;

[0214] S230: Real-time acquisition of the relative material type values ​​between the baseline material and the reference material;

[0215] S240: Based on the relationship function between the passive nuclear level gauge's measurement distance to the reference material, the maximum detection distance of the reference material, and the real-time relative material type value, the measurement distance of the passive nuclear level gauge to the reference material is calculated. The real-time relative material type value is defined as the ratio of the nuclear radiation characteristic data of the real-time reference material detected by the material type identification and correction instrument to the nuclear radiation characteristic data of the reference material.

[0216] In step S240, the passive nuclear level gauge measures the distance of the real-time reference material (denoted as...). R 2) The maximum detection distance of the reference material (denoted as...) R 1) Real-time relative material type value between the real-time benchmark material and the reference material (denoted as...) P The relationship function between ) is constructed as follows:

[0217] R 2= R1× ,in, R 2 represents the measurement distance of the level gauge to the real-time reference material. R 1 represents the maximum detection distance of the reference material obtained through pre-measurement or calculation; P This represents the real-time relative material type value between the real-time baseline material and the reference material.

[0218] Real-time relative material type value P Defined as the ratio of the real-time nuclear radiation characteristic data of the reference material detected by the material type identification and correction instrument to the nuclear radiation characteristic data of the reference material, it is obtained in the following way:

[0219] Real-time reference material and reference material of the same height, volume or weight were placed in the same first dedicated metering tank. The nuclear radiation characteristic data of the real-time reference material were measured using the same material type identification and correction instrument. C 2. Nuclear radiation characteristic data of reference materials C 1;

[0220] Calculate the relative planting material using the formula. P = C 2 / C 1.

[0221] Nuclear radiation characteristic data of reference material were obtained in a single measurement. C 1. Maximum detection distance of reference material R After 1, it is stored as a calibration parameter; in other words, relative to the planting material. P It is based on the nuclear radiation characteristics data released by real-time reference materials. C It changes with the changes in 2, that is, by acquiring real-time nuclear radiation characteristic data. C 2. To calculate the real-time relative planting material P Specifically, to obtain real-time nuclear radiation characteristic data. C Method 2 is as follows:

[0222] The system also includes a second dedicated metering tank, which is controllably connected to the container being measured; in response to the computational control module's requirement to calculate the measurement distance of the passive nuclear level gauge to the reference material (i.e., to calculate the real-time relative material level), P To meet the requirements, a sample of material with the same height, volume, or weight as the reference material is extracted from the container being measured and discharged into a second dedicated metering tank. This second dedicated metering tank is also equipped with a device configured to detect the nuclear radiation characteristics released by the real-time reference material within it. C 2. Material type identification and correction instrument.

[0223] As mentioned above, the maximum detection distance of the reference material R1 is obtained through prior measurement or calculation. The measurement and calculation methods are explained in detail below:

[0224] Figure 6 The steps shown are for obtaining the maximum detection distance of the reference material by measurement. R 1:

[0225] S311: Measure the nuclear radiation data of reference materials using a passive nuclear level gauge;

[0226] S312: Move the passive nuclear level gauge to find the extreme position where its nuclear radiation measurement results change abruptly;

[0227] S313: Use a length measuring tool to measure the closest distance from the extreme position to the reference material, and use it as the maximum detection distance of the reference material.

[0228] Figure 7 The steps shown are for calculating the maximum detection distance of the reference material. R 1:

[0229] S321: Determine the current detection distance between the passive nuclear level gauge and the reference material. R 11 ;

[0230] S322: Detecting nuclear radiation data emitted by reference materials. I 11 ;

[0231] S323: Calculate the maximum detection distance of the reference material using the following formula. R 1: R 1= R 11 × ,in, I 1 represents the limiting radiation value corresponding to the passive nuclear level metering range.

[0232] The maximum detection distance of the reference material is obtained in advance by measurement or calculation. R 1. Substitute R 2= R 1× That is, the measurement distance of the passive nuclear level gauge relative to the fixed position of the measured container to the reference material is calculated.

[0233] Third embodiment: The calculation control module calculates the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material through a fitting function. The calculation methods for measurement range / measurement distance are explained below according to different fitting functions:

[0234] First Fitting Example: The first implementation method is to directly obtain polynomial coefficients with defined characteristics from other sources. a 0 to a n Fitting function: L = a n ×q n + a n-1 ×q n-1 +...+ a 1×q+ a 0, where, L q represents the measurement range of the passive nuclear level gauge relative to a fixed position within the container being measured, where q is the nuclear radiation characteristic data of the material being measured within the container. a 0 to a n For polynomial coefficients, a n ≠0, n ≥2; In response to the trigger action, the current nuclear radiation characteristic data q of the material type identification and correction instrument is substituted into the above fitting formula to obtain the measurement range of the passive nuclear level gauge relative to the fixed position of the measured container. L .

[0235] The second implementation of the first fitting embodiment is to construct the measurement range of the passive nuclear level gauge at a fixed position in the container being measured. L The fitting function between the material and the nuclear radiation characteristic data q of the material to be tested; the material is measured in the container to obtain test data including the measurement range and nuclear radiation characteristic data; based on the test data, the coefficients in the fitting function are determined; the nuclear radiation characteristic data of the material to be tested is detected by the material type identification and correction instrument, and the data is substituted into the fitting function after the coefficients are determined to obtain the corresponding measurement range.

[0236] This invention does not limit the fitting function to... L = a n ×q n + a n-1 ×q n-1 +...+ a 1×q+ a 0 allows for variations of this function without creative effort. To determine the coefficients in the fitting function, experimental data on the correlation between parameters other than the coefficients to be determined can be obtained based on experiments. Then, data fitting can be performed on the higher-order polynomial to determine the polynomial coefficients.

[0237] Second Fitting Example: The first implementation method is to directly obtain a fitting function with determined coefficients from other sources: L=(1 / μ )× ln ([q×V×) A ] / I )+ D ,in, L The measurement distance of the passive nuclear level gauge at a fixed position in the container being measured to the reference material is given by: q represents the nuclear radiation characteristic data of the material to be measured, and V represents the quantity data of the reference material. I This represents the limiting radiation value corresponding to the passive nuclear level metering range. μ The linear attenuation coefficient is... A These are calibration coefficients used to correct the deviation between the theoretical model and the actual measurement system. D Let be the correction constant used to compensate for errors, where is the limiting radiation value. I These are the performance parameters of the passive nuclear level gauge, where V represents one or more of the height, volume, and weight of the reference material being measured. μ , A , D These are the coefficients that have been determined as mentioned above;

[0238] The second implementation of the second fitting embodiment involves constructing a fitting function between the measurement distance of the passive nuclear level gauge to the reference material, the quantity data of the reference material, and the nuclear radiation characteristic data. The quantity data of the reference material can be one or more of height, volume, and weight. Measurement experiments are conducted on the reference material to obtain experimental data including the measurement distance of the passive nuclear level gauge to the reference material, the quantity data of the reference material, and the nuclear radiation characteristic data. Based on the experimental data, the coefficients in the fitting function are determined. A material type identification and correction instrument is used to detect the nuclear radiation characteristic data of the material to be measured, the quantity data value of the reference material is selected, and substituted into the fitting function after determining the coefficients to obtain the corresponding measurement distance.

[0239] This invention does not limit the fitting function to the above-mentioned one. L =(1 / μ )× ln ([q×V×) A ] / I )+ D Furthermore, implementation methods corresponding to other functions that are simply modified without requiring creative effort also fall within the scope of protection claimed by this invention. L =(1 / μ )× ln ([q×V×) A ] / I )+ D For example, based on experiments, multiple sets of associated measured distances were obtained. LThe data includes the quantity of reference material V and the nuclear radiation characteristic data q. Based on the experimental data, the linear decay coefficient in the fitting function is determined. μ、 Correction constant D and calibration coefficient A .

[0240] In response to the trigger action, the current nuclear radiation characteristic data q of the material type identification corrector, the quantity data V of the reference material, and the limiting radiation parameter value of the passive nuclear level gauge are updated. I Substituting into the above fitting formula, we obtain the measurement distance of the passive nuclear level gauge relative to the fixed position of the measured container to the reference material.

[0241] Third fitting example: Based on the relational function constructed in the second example R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the reference material. P This refers to the real-time relative material type values ​​between the real-time benchmark material and the reference material, and the maximum detection distance of the reference material obtained through measurement or calculation in the second embodiment. R The difference is that the third fitting embodiment uses a fitting formula to obtain the maximum detection distance of the level gauge for the reference material:

[0242] The first implementation of the third fitting embodiment involves directly obtaining a fitting function with defined polynomial coefficients from other sources to calculate the measurement distance of the passive nuclear level gauge to the reference material. The specific fitting function is any of the following formulas:

[0243] R 1 = b n ×V n + b n-1 ×V n-1 +...+ b 1×V+ b 0, where R 1 represents the maximum detection distance of the level gauge for the reference material, and V represents the quantity of the reference material. b 0 to b n For polynomial coefficients, b n ≠0, n ≥2;

[0244] or, R 1 = c n × H ref n + cn-1 × H ref n-1 +...+ c 1× H ref + c 0, where, R 1. Maximum detection distance for reference materials H ref For reference material height data, c 0 to c n For polynomial coefficients, c n ≠0, n ≥2.

[0245] Obtain the quantity data V (height, volume, and / or weight) of the reference material and substitute it into the previous fitting function, or use the height data of the reference material. H ref Substituting the previous fitting function, the maximum detection distance of the level gauge to the reference material is calculated. R 1. And store it as a calibration parameter.

[0246] In response to the trigger action, referring to the second embodiment, a material of the same height, volume, or weight as the reference material is extracted from the container being measured using a second dedicated metering tank as a real-time reference material and discharged into the second dedicated metering tank. A material type identification and correction instrument is then used to detect the real-time nuclear radiation characteristic data released by the real-time reference material in the second dedicated metering tank. C 2. Combine the nuclear radiation characteristic data of the reference material stored as calibration parameters. C 1. It can calculate the real-time relative planting material. P = C 2 / C 1; and then combine this with the maximum detection distance of the reference material stored as a calibration parameter. R 1. Calculate the measurement distance of the passive nuclear level gauge relative to the fixed position of the measured container and the reference material. R 2= R 1× .

[0247] The second implementation of the third fitting embodiment involves constructing a fitting function between the maximum detection distance of the passive nuclear level gauge to the reference material and the quantity data of the reference material. The quantity data of the reference material can be one or more of height, volume, and weight. Measurement experiments are conducted on the material to obtain multiple sets of related experimental data on the maximum detection distance and quantity data of the reference material. Based on the experimental data, the coefficients in the fitting function are determined. The current quantity data of the reference material is obtained and substituted into the fitting function after the coefficients are determined to obtain the corresponding maximum detection distance to the reference material.

[0248] This invention does not limit the fitting function to the above-mentioned one. R 1 = b n ×V n + b n-1 ×V n-1 +...+ b 1×V+ b 0. Implementations corresponding to other functions that are simple modifications of this invention without requiring creative effort also fall within the scope of protection claimed by this invention. R 1 = b n ×V n + b n-1 ×V n-1 +...+ b 1×V+ b Taking 0 as an example, based on experiments, the maximum detection distance of multiple sets of associated level gauges for reference materials was obtained. R 1. Refer to the quantity data V of the reference material; based on the correlation data obtained from the experiment, perform data fitting on the high-order polynomial, and determine the polynomial coefficients in the fitting function. b 0 to b n .

[0249] After determining the fitting function, obtain the quantity data V (height, volume, and / or weight) of the reference material, substitute it into the previous fitting function, and calculate the maximum detection distance of the level gauge for the reference material. R 1. And store it as a calibration parameter.

[0250] In response to the triggering action, the method for calculating the measurement distance of the passive nuclear level gauge relative to the fixed position of the measured container to the reference material is the same as that in the first implementation of the third fitting embodiment, and will not be repeated here.

[0251] The third implementation of the third fitting embodiment involves constructing a fitting function between the maximum detection distance of the passive nuclear level gauge to the reference material and the height data of the reference material; conducting measurement experiments on the material to obtain experimental data including the maximum detection distance and the height data of the reference material; determining the coefficients in the fitting function based on the experimental data; replacing the height of the reference material in the fitting function after determining the coefficients with the difference between the installation height of the passive nuclear level gauge and the maximum detection distance to obtain a new function; and substituting the current installation height of the passive nuclear level gauge into the new function to calculate the corresponding maximum detection distance of the reference material.

[0252] This invention does not limit the fitting function to the above-mentioned one. R 1 = c n × H ref n + c n-1 × H ref n-1 +...+ c 1× H ref + c 0. Implementations corresponding to other functions that are simple modifications of this invention without requiring creative effort also fall within the scope of protection claimed by this invention. R 1 = c n × H ref n + c n-1 × H ref n-1 +...+ c 1× H ref + c Taking 0 as an example, based on experiments, the maximum detection distance of multiple sets of associated level gauges for reference materials was obtained. R 1. Reference material height data H ref The experimental data; based on the correlation data obtained from the experiment, data fitting is performed on the high-order polynomial to determine the polynomial coefficients in the fitted function. c 0 to c n .

[0253] After determining the fitting function, obtain the height data of the reference material. H ref Substituting this into the previous fitting function, the maximum detection distance of the level gauge for the reference material is calculated. R1. And store it as a calibration parameter.

[0254] In response to the trigger action, the method of calculating the measurement distance of the passive nuclear level gauge relative to the reference material at a fixed position relative to the measured container after determining the fitting function is the same as the first implementation of the third fitting embodiment, and will not be repeated here.

[0255] The fourth implementation of the third fitting embodiment differs from the third implementation in that it determines the fitting function. R 1 = c n × H ref n + c n-1 × H ref n-1 +...+ c 1× H ref + c After 0 (polynomial coefficients) c 0 to c n (This has been determined), defining the installation height of the passive nuclear level gauge at a fixed position relative to the measured container as: H sum ,based on H ref = H sum - R 1. A new function is obtained as the function for calculating the maximum detection distance of the reference material: R 1 = c n ×( H sum - R 1) n + c n-1 ×( H sum - R 1) n-1 +...+ c 1×( H sum - R 1)+ c 0.

[0256] After determining the fitting function, unlike the third implementation of the third fitting example, it is not necessary to measure the height data of the reference material. H ref Given that the installation height of the passive nuclear level gauge at a fixed position relative to the measured container is... H sumUnder these conditions, the maximum detection distance of the reference material can be calculated. R 1. And store it as a calibration parameter.

[0257] In response to the trigger action, the method of calculating the measurement distance of the passive nuclear level gauge relative to the reference material at a fixed position relative to the measured container after determining the fitting function is the same as the first implementation of the third fitting embodiment, and will not be repeated here.

[0258] In the above embodiments, the passive nuclear level gauge used to measure the reference material can be the same or the same model as the target passive nuclear level gauge used to measure the reference material, or it can be other types of nuclear radiation measuring equipment. The nuclear radiation measuring equipment and the passive nuclear level gauge have the same nuclear radiation detection performance, or the nuclear radiation detection performance of the nuclear radiation measuring equipment is derived from the nuclear radiation detection performance of the passive nuclear level gauge. This invention does not limit this.

[0259] In the above embodiments, the container used for testing is replaced by another container, which has the same structure as the container being measured, or the structure of the other container is a scaled-up or scaled-down version of the container being measured.

[0260] Fourth embodiment: The system also includes a third-party device that executes the measurement steps triggered by the computing control module, such as... Figure 2 As shown, the third-party equipment includes a material level detection device, a track whose positional relationship with the container being measured is determined, and a nuclear radiation sensor that can be driven to move on the track.

[0261] Material level detection devices include visual recognition devices, radar devices, ultrasonic devices, weighing devices, or touch switches that can move downward relative to the container being measured, which can detect the actual height of the material.

[0262] Based on the actual height of the material in the container being measured provided by the material level detection device and the critical position where the nuclear radiation sensor moves to zero, the measurement range of the nuclear radiation sensor is obtained.

[0263] Based on the range conversion relationship between nuclear radiation sensors and passive nuclear level gauges, the measurement range of the passive nuclear level gauge is obtained.

[0264] Under the control of the computational control module, the third-party equipment performs the measurement operation as follows: the material level detection device detects the actual height of the material in the container being measured, drives the nuclear radiation sensor to move along the track to the critical position where the detection data becomes zero, and obtains the measurement range of the nuclear radiation sensor; if the nuclear radiation sensor is a passive nuclear level gauge of the same model, then the measurement range of the nuclear radiation sensor obtained is the measurement range of the passive nuclear level gauge, otherwise, the measurement range of the nuclear radiation sensor is converted to the measurement range of the passive nuclear level gauge according to the ratio between the two ranges.

[0265] Fifth Embodiment: The calculation control module obtains the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material by querying a preset mapping relationship between nuclear radiation characteristic data and the measurement range of the passive nuclear level gauge, or a preset mapping relationship between nuclear radiation characteristic data and the measurement distance of the passive nuclear level gauge to the reference material. Often, establishing the correspondence between the nuclear radiation characteristic data and the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material is a prerequisite step for establishing a fitting function. In the process of establishing the fitting function in the third embodiment of this application, the correspondence between the measurement range or the measurement distance to the reference material is generally established first. If the above correspondence is directly preset in the calculation control module, the calculation control module can directly obtain the measurement range or measurement distance corresponding to the radioactive characteristic data of the material by querying the correspondence.

[0266] The fifth embodiment is simpler than the third embodiment, but when the radioactivity characteristic data of the material is not in a preset relationship, the measurement range or measurement distance cannot be directly obtained. In this case, it can be indirectly derived from pre-stored data that is correlated with the radioactivity characteristic data of the material. The indirect derivation method can be, for example, using a linear calculation method; or the measurement range or measurement distance corresponding to the closest nuclear radioactivity characteristic data can be used as the result output.

[0267] In addition to the measurement experiment conducted on the material in the measured container as in the first fitting embodiment of the third embodiment, to obtain test data including the measurement range and nuclear radiation characteristic data mapping relationship, and to remove obvious noise data to obtain the above-mentioned mapping relationship data, this fifth embodiment can also use the nuclear radiation field formula of the first embodiment to pre-calculate a series of discrete nuclear radiation characteristic data and the corresponding measurement range of the passive nuclear level gauge.

[0268] Establishing a mapping relationship between material type and measurement range or distance using experimental methods is a very simple and effective approach. After obtaining the mapping relationship data through experiments, users or manufacturers can preset it into the measurement range or distance determination system of this application. If a new range or distance needs to be generated, the calculation and control module only needs to query the mapping relationship data to obtain the corresponding measurement range for the material type or the measurement distance for the reference material.

[0269] When establishing the mapping relationship, a mapping relationship can be established between the material type and the measurement range of the passive nuclear level gauge installed on the container. For example, if the passive nuclear level gauge in this application system is installed at the height H of the container, and the material types A1, A2, A3, A4, A5, and A6 are obtained through testing, the measurement ranges of the passive nuclear level gauge are H1, H2, H3, H4, H5, and H6, respectively. This one-to-one mapping relationship is preset in the calculation and processing module of this application. After obtaining the material type value A3, the calculation and processing module queries the mapping relationship and obtains that the corresponding measurement range of the passive nuclear level gauge is H3.

[0270] Accordingly, based on this application, a mapping relationship between material type and measurement distance of reference material can be established. For example, when the quantity of reference material is V1 obtained through experimentation, and the material types are A1, A2, A3, A4, A5, and A6, the measurement range of the passive nuclear level gauge is L1, L2, L3, L4, L5, and L6, respectively. This one-to-one mapping relationship is preset in the calculation and processing module of this application. After obtaining the material type value as A3, the calculation and processing module queries the mapping relationship to obtain that the corresponding measurement range of the passive nuclear level gauge is L3.

[0271] For the measurement distance of the reference material, a mapping relationship between the material type and the measurement distance can be established for various quantity conditions, such as the correspondence between the material type and the measurement distance under the conditions of quantity V1, V2, V3, etc.

[0272] It should be noted that the testing and application scenarios for the reference material can be conducted within the container being measured. When the quantity is VH1 and the material types are A1, A2, A3, A4, A5, and A6, the measurement distances of the passive nuclear level gauge (which is not fixed but mobile and can be replaced by other nuclear radiation measuring equipment) are L1, L2, L3, L4, L5, and L6, respectively. This measurement distance has no significant effect on the measurement range of a passive nuclear level gauge installed at a fixed position on the container. However, in this application, a mapping relationship can be established within the container being measured for a larger number of materials, such as VH1, VH2, and VH3, with material types A1, A2, A3, A4, A5, and A6, with measurement distances of L1, L2, L3, L4, L5, and L6, and this relationship is preset in the processing module.

[0273] Clearly, simply querying the mapping relationship cannot directly yield the measurement range of the passive nuclear level gauge installed at a fixed position on the container when the material type value is A1. This is because the calculation method for determining the measurement range or distance, the method for controlling third-party equipment, and the method for querying the mapping relationship described in this application can be used independently or in combination. In real-time use, the required measurement range or distance can be obtained by repeatedly using the same method.

[0274] Therefore, based on the mapping relationship between different quantities of material and measurement distance constructed above, and the fact that the base material quantity (when expressed as height) plus the measurement distance equals or is close to the installation height of the passive nuclear level gauge on the container, according to the material data, VH+L (or a mapping relationship between material data and VH+Ld can be established in advance) equals or is close to the installation height of the passive nuclear level gauge on the container. The VH or L that meets the requirements is or is close to the measurement range of the passive nuclear level gauge.

[0275] In practical implementation, when constructing the mapping relationship, data on the mapping relationship between materials outside the measurement range and the passive nuclear level gauge can be collected, as can data on the mapping relationship between materials within the measurement range and the passive nuclear level gauge. This is because the measurement range is essentially the boundary between a measurable area and an unmeasurable area. Of course, if the material in the container submerges the installation height of the passive nuclear level gauge, using experimental data and material type mapping relationships for materials within the measurement range is more accurate. When the material does not reach the installation position of the passive nuclear level gauge, using experimental data and material type mapping relationships for materials outside the measurement range is more accurate.

[0276] This invention does not limit the specific architecture of the computing control module in the system. It can be integrated into the material type identification and correction device, or into a passive nuclear level gauge. Alternatively, the computing control module can be an external device connected to the material type identification and correction device via wired or wireless connection. The external device can even be a DCS or PLC system in an industrial site, or a big data or AI operating device.

[0277] In practical implementation, the functions of the calculation and control module can also be implemented by the processing unit of the material type identification and correction instrument or the processing unit of the passive nuclear level gauge. That is, the processing unit in the material type identification and correction instrument or the passive nuclear level gauge described in this application can concurrently serve as the calculation and control module of this application, completing its functions and operations. This also saves costs to a considerable extent.

[0278] Applicable to all the above embodiments, the passive nuclear level gauge measurement range or measurement distance determination system provided by the present invention also includes a display device, such as... Figure 1As shown, the display device is configured to display the current measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material, and / or to display the level measurement result of the passive nuclear level gauge;

[0279] The system may also include an output module configured to send the measurement range and / or level measurement results to a remote client via wired and / or wireless output.

[0280] This invention does not limit the specific architecture of the display device in the system. For example, the display device can be integrated with a passive nuclear level gauge, a material type identification and correction device, or a calculation and control module. Alternatively, the display device can be wired or wirelessly connected to the passive nuclear level gauge, the material type identification and correction device, and the calculation and control module.

[0281] In one embodiment of the present invention, a method for determining the measurement range or measurement distance of a passive nuclear level gauge is provided. The method comprises the following steps: determining the measurement range of the passive nuclear level gauge at a fixed position relative to the container being measured, or the measurement distance of the passive nuclear level gauge to a reference material.

[0282] The nuclear radiation characteristics data released by the material inside the measured container were detected using a material type identification and correction instrument.

[0283] like Figure 8 As shown, in response to the material type identification and correction instrument outputting material nuclear radiation characteristic data, or if the change in nuclear radiation characteristic data output by the material type identification and correction instrument at least twice exceeds the preset condition, the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material is calculated according to the preset algorithm.

[0284] Or such as Figure 9 As shown, in response to the material type identification correction instrument outputting material nuclear radiation characteristic data, or if the change in nuclear radiation characteristic data output by the material type identification correction instrument at least twice exceeds a preset condition, a third-party device is controlled to perform a measurement to obtain the measurement range of the passive nuclear level gauge or the measurement distance of the passive nuclear level gauge to the reference material.

[0285] Figure 8 The preset algorithm is any one of the following four algorithms: Algorithm 1, Algorithm 2, Algorithm 3, and Algorithm 4.

[0286] The first algorithm is to construct a nuclear radiation field formula based on nuclear radiation characteristic data, measurement layout geometric parameters, material height inside the container, and the limiting radiation value corresponding to the passive nuclear level gauge's measurement range. The limiting radiation value corresponding to the passive nuclear level gauge's measurement range is the nuclear radiation data obtained by the passive nuclear level gauge at the distance position corresponding to the measurement range. The measurement layout geometric parameters include the geometric data of the measured container and the installation position parameters of the passive nuclear level gauge relative to the measured container. The measurement range of the passive nuclear level gauge is determined, and the relative value between the installation position and the material inside the measured container is determined, or the material height inside the measured container is the measurement range of the level gauge.

[0287] The second algorithm is to prepare reference material; pre-calculate or measure the maximum detection distance of the reference material and the real-time relative material type value between the reference material and the benchmark material; construct the relationship function between the measurement distance of the passive nuclear level gauge to the benchmark material, the maximum detection distance of the reference material, and the real-time relative material type value, wherein the real-time relative material type value is defined as the ratio of the nuclear radiation characteristic data of the real-time benchmark material detected by the material type identification and correction instrument to the nuclear radiation characteristic data of the reference material;

[0288] The third algorithm involves constructing a fitting function between the measurement range of the passive nuclear level gauge at a fixed position in the measured container and the nuclear radiation characteristic data of the material to be measured, or constructing a fitting function between the measurement distance of the passive nuclear level gauge to the reference material and the quantity data of the reference material, or constructing a fitting function between the measurement distance of the passive nuclear level gauge to the reference material, the quantity data of the reference material, and the nuclear radiation characteristic data; conducting measurement experiments on the material and determining the coefficients in the fitting function based on the experimental data; and using the fitting function after determining the coefficients to calculate the corresponding measurement range of the level gauge or the measurement distance of the level gauge to the reference material.

[0289] The fourth algorithm involves constructing a fitting function between the maximum detection distance of the passive nuclear level gauge to the reference material and the quantity data of the reference material; conducting measurement experiments on the material and determining the coefficients in the fitting function based on the experimental data; using the fitting function with determined coefficients to calculate the maximum detection distance of the passive nuclear level gauge to the reference material; and using a formula to calculate the measurement distance of the passive nuclear level gauge to the reference material. R 2= R 1× ,in, R 2 represents the measurement distance of the level gauge to the reference material. P This refers to the real-time relative material type values ​​between the real-time baseline material and the reference material. R 1 represents the maximum detection distance of the reference material.

[0290] It should be noted that the passive nuclear level gauge measurement range or measurement distance determination method provided in this embodiment of the invention belongs to the same concept as the passive nuclear level gauge measurement range or measurement distance determination system provided in the above embodiment. Here, all the contents of the passive nuclear level gauge measurement range or measurement distance determination system embodiment are incorporated into this passive nuclear level gauge measurement range or measurement distance determination method embodiment by reference.

[0291] In actual implementation, during the process of determining the measurement range or measurement distance of the passive nuclear level gauge, the reference material in the above four methods is either the material outside the range edge or the material within the range.

[0292] When the passive nuclear level gauge on the calculation container is installed from the bottom of the container to when it is filled with material, or when the installation position of the passive nuclear level gauge is within the upward measuring range or measuring distance of the passive nuclear level gauge, the medium in the measuring space is material.

[0293] Because the absorption coefficients of materials and air differ significantly, the actual measuring range of passive nuclear level gauges is very small. The absorption coefficient of air is often negligible, while the absorption coefficient of materials is relatively large. Therefore, there is a significant difference between measuring the reference and actual materials through air and measuring the reference and actual materials through the material itself to obtain the measurement range and distance. Of course, since the measuring range primarily expresses the measurement boundary from empty to filled space, the measurement range and measurement distance to the reference material that we usually refer to are in space.

[0294] However, regardless of whether air or material is used as the medium, the calculation method of this application is the same; only the medium traversed during the measurement process is different.

[0295] Meanwhile, when using the second, third, and fourth algorithms for calculation, the reference material or benchmark material can be either outside the measurement range or within the measurement range.

[0296] For example, during experiments, material can be filled between the reference material or standard material and the passive nuclear level gauge to obtain the measurement range or distance. The actual amount of material filled also represents the measurement range or distance. When calculating based on the maximum range or measurement distance, the real-time maximum range of the material under the specific material type must also be calculated based on the filled material.

[0297] One embodiment of the present invention provides a passive nuclear level gauge method for measuring level, comprising the following steps:

[0298] The current measurement range of the passive nuclear level gauge is determined using the measurement range or measurement distance determination system described above.

[0299] If the level value generated by the passive nuclear level gauge is less than or equal to the preset level threshold (which can tolerate edge calculation errors, such as setting the level threshold to 0.1 meters), or if the nuclear radiation value measured by the passive nuclear level gauge is less than or equal to the preset nuclear radiation threshold, the passive nuclear level gauge will output a prompt message in a preset format, which includes the current measurement range information.

[0300] In practical applications, if conditions permit, two signals can be output to the user's operating terminal: one to display the level data measured by the passive nuclear level gauge, and the other to display the real-time range data.

[0301] However, in actual production, adding a signal line would significantly increase costs and equipment. This is especially true when upgrading existing lines; it's simply impractical to add a signal cable, cards, etc., just to display real-time measurement ranges.

[0302] In this embodiment, the passive nuclear level gauge can output prompt information in a preset format. For example, in the existing passive nuclear level gauge output level data circuit, the output level signal includes real-time measurement range data. For instance, when the level value measured by the passive nuclear level gauge is less than 0.1 meters, or when the measured value is less than a preset measurement value (e.g., 200), the passive nuclear level gauge displays the level data and real-time range data at intervals. For example, it displays the level data of 0.1 meters for 3 seconds, then displays the real-time measurement range of 3 meters for 3 seconds, then displays the 3-meter level data again, and so on. Since the user knows the preset format beforehand, the user can easily obtain both real-time level data and real-time range data simultaneously.

[0303] In actual implementation, when the level data of the passive nuclear level gauge is greater than 0.1 meters, or the measured value is greater than 200, it means that the material has entered the measurement range of the passive nuclear level gauge and the material level can be displayed normally. At this time, it is not necessary to output the prompt information containing the real-time measurement range data in the preset format as mentioned above.

[0304] In practice, many formats can be preset to express real-time range information. For example, the real-time range value can be flashed, but the material level cannot be output (because the material level cannot be measured at this time), while the normal material level data is continuously displayed without flashing. For example, the preset format can output data with attribute markings. The running end can determine whether it is material level data or real-time range data based on the acquired data attributes. If it is real-time range data, it will be marked on the running end screen: Real-time range is 3 meters.

[0305] When a passive nuclear level gauge cannot detect the material inside a container, outputting real-time range data is extremely important in actual operation. For example, if a passive nuclear level gauge is installed at a fixed height of 5 meters from the bottom of the container, and its current measurement range is 3 meters, then when the material entering the container is less than 2 meters high, the passive nuclear level gauge cannot detect the nuclear radiation from the material (it can only detect ambient radiation). The traditional approach is for the passive nuclear level gauge to output a level value of 0, or to estimate a value within the 0-2 meter range; this makes it impossible for the user to determine whether the material inside the container is below the gauge's measurement range or whether there is actually no material inside the container.

[0306] The problem with existing technology is that users know that when a passive nuclear level gauge is installed at a 5-meter position, its downward detection range is only 3 meters. This means the passive nuclear level gauge cannot measure the 0-2 meter range. The question then becomes: should the display on the operating screen show 0 meters or 2 meters? If it shows 0 meters, users are easily complacent when the material level is between 0 and 2 meters, potentially leading to safety issues. If it shows 2 meters, users will obviously conclude that the passive nuclear level gauge is inaccurate and does not reflect the actual situation when the material level is between 0 and 2 meters, especially when the silo is empty.

[0307] More critically, current technology lacks the means to generate real-time measurement ranges for passive nuclear level gauges detecting materials within containers. This means users have no way of knowing the actual range of the passive nuclear level gauge. If the current real-time range is only 0.5 meters, while existing technology has a fixed range of 3 meters, users cannot determine the real-time range. Once material enters the measurement range, the situation is already dangerous, resulting in extremely short reaction times and hindering proper preparation, severely impacting operational safety.

[0308] By employing the solution of this invention, users can clearly know the current real-time measurement range of the passive nuclear level gauge. Even if the same material is not within the measurement range of the passive nuclear level gauge, users can relax their vigilance if they know the actual range is relatively large. Conversely, if the actual range is very small, users must be more cautious to avoid entering the measurement range only to find the actual material level is already high, as negligence could lead to a safety accident.

[0309] See Figure 10 An embodiment of the present invention provides a passive nuclear level gauge method for measuring level, comprising the following steps:

[0310] After determining the current measurement range of the passive nuclear level gauge using the measurement range or measurement distance determination system described above, the method further includes a step of calculating the actual material level inside the container using the current measurement range of the passive nuclear level gauge.

[0311] Based on the difference between the measured value of the passive nuclear level gauge and the preset empty container value, the difference between the real-time full container value and the preset empty container value, and the measurement range, the relative material level value within the measurement range is calculated. The relative material level value is the material level value measured from the edge of the measurement range within the measurement range of the passive nuclear level gauge.

[0312] It should be noted that the aforementioned real-time full-load value is not a preset value, but rather a value calculated by the passive nuclear level gauge based on real-time material radioactivity characteristic data. The radioactivity characteristic data is described in detail in the applicant's Chinese patent application with publication number CN104482996A, and will not be repeated here. Furthermore, the relative level value within the measurement range mentioned above in this application is the same level value recorded in Chinese patent application with publication number CN119223400A, as that patent is based on the entire material being within the measurement range. Since this application considers that in many cases, a portion of the material does not enter the measurement range of the passive nuclear level gauge, this embodiment improves upon the shortcomings of existing technologies by using real-time measurement range data, making the passive nuclear level gauge measurement more accurate. Therefore, the calculation method for the relative level value will not be elaborated in this application.

[0313] If the difference between the relative installation height and the measuring range of the passive nuclear level gauge is greater than or equal to 0, then the sum of the relative level value and the difference between the relative installation height and the measuring range of the passive nuclear level gauge is calculated to obtain the level value of the material in the container.

[0314] It should be noted that in practical applications, if the difference between the relative installation height and the measurement range of the passive nuclear level gauge is less than 0, the product of the ratio and the installation height of the passive nuclear level gauge is calculated to obtain the material level value in the container.

[0315] Specifically as follows:

[0316] The nuclear radiation values ​​measured by the passive nuclear level gauge are preset in the empty and full states of the container being measured, respectively. C empty and C full Nuclear radiation levels in an empty warehouse C empty This refers to the environmental radiation value, specifically the real-time detected nuclear radiation value. C real Exceeding the nuclear radiation level in an empty chamber C emptyWhen the material is considered to have entered the measurement range of the passive nuclear level gauge, the reading of the material type identification and correction instrument will usually change significantly. Therefore, it is easy to trigger the calculation and control module to calculate the measurement range of the passive nuclear level gauge, or trigger the calculation and control module to control a third-party device to perform measurement to obtain the measurement range of the passive nuclear level gauge.

[0317] The traditional formula for calculating the relative material level is as follows: H real = H max ×( C real - C empty ) / ( C full - C empty ),in, H real This represents the real-time material level height. H max The total height of the container. H relative The relative level value of the material within the measurement range of the passive nuclear level gauge. C real This represents the current real-time nuclear radiation value detected by the passive nuclear level gauge. C full This represents the real-time nuclear radiation level of materials at full capacity.

[0318] The height of the passive nuclear level gauge relative to the fixed position of the measured container is defined as... L 2; This embodiment utilizes the current measurement range. L 1. Calculate the relative material level value within the measurement range of the passive nuclear level gauge, as follows:

[0319] H relative = L 1×( C real - C empty ) / ( C full - C empty );

[0320] In the above calculation formula L 1×( C real - C empty ) / ( C full - C emptyThis represents the relative material level within the measurement range. Of course, in practice, this is determined when obtaining or knowing... L 1. C real , C empty , C full , C empty After obtaining the data, the relative material level value can also be obtained based on the preset fitting function, data correspondence, etc.

[0321] like L 2- L If 1 ≥ 0, then the material level value inside the container can be calculated:

[0322] H real = L 1×( C real - C empty ) / ( C full - C empty ) + ( L 2- L 1).

[0323] Obviously, if the radioactivity characteristics of materials differ significantly, existing level algorithms do not take into account the differences in the real-time measurement range of passive nuclear level gauges, resulting in highly inaccurate measurements. However, in the embodiments of this application, after obtaining the actual measurement range of the passive nuclear level gauge, a much more accurate material level can be obtained than that of existing technologies.

[0324] By optimizing the traditional relative level calculation algorithm by measuring the range of a passive nuclear level gauge at a fixed position in the container being measured, the algorithm considers the relative relationship between the nuclear radiation values ​​of an empty or full container and the measurable range, the installation height of the level gauge, and the total height of the container, making the level calculation result closer to the actual level height.

[0325] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0326] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A passive nuclear inventory gauge measurement range or measurement distance determination system for determining a measurement range of a passive nuclear inventory gauge at a fixed position relative to a container being measured or a measurement distance of a passive nuclear inventory gauge to a reference material, the system comprising: a reference material; a passive nuclear inventory gauge; a measurement device; and a computer system, wherein the computer system is configured to: determine a measurement range of the passive nuclear inventory gauge at the fixed position relative to the container being measured or a measurement distance of the passive nuclear inventory gauge to the reference material; and output a result of the determination. The system comprises a passive nuclear material level meter, a material type identification correction instrument and a computing control module, wherein the material type identification correction instrument and the passive nuclear material level meter are respectively connected with the computing control module in communication; The material type identification correction instrument is configured to detect nuclear radiation characteristic data released by the material in the measured container; In response to a preset trigger condition, the computing control module is configured to perform at least one of the following operations: The computing control module calculates the measurement range of the passive nuclear material level meter or the measurement distance of the passive nuclear material level meter to the reference material according to a preset algorithm; The computing control module controls a third-party device to perform measurement to obtain the measurement range of the passive nuclear material level meter or the measurement distance of the passive nuclear material level meter to the reference material; The computing control module determines the measurement range of the passive nuclear material level meter corresponding to the nuclear radiation characteristic data or the measurement distance of the passive nuclear material level meter to the reference material corresponding to the nuclear radiation characteristic data by querying a preset mapping relationship; The computing control module is integrated in the material type identification correction instrument, or the computing control module is integrated in the passive nuclear material level meter, or the computing control module is an external device connected with the material type identification correction instrument in wired or wireless manner, or the function of the computing control module is realized by an operation processing unit of the material type identification correction instrument or an operation processing unit of the passive nuclear material level meter.

2. The passive nuclear inventory level gauge measurement range or measurement distance determining system according to claim 1, characterized in that The preset trigger condition comprises at least one of the following: Receiving an external signal; Passing a preset timing duration; Arriving at a preset time; Receiving a signal that the passive nuclear material level meter accesses the system; The material type identification correction instrument outputs material nuclear radiation characteristic data; The change of the nuclear radiation characteristic data output by the material type identification correction instrument at least twice exceeds a preset condition; The nuclear radiation data or material level value measured by the passive nuclear material level meter is higher than a preset threshold value; The measurement result of the passive nuclear material level meter represents that the radiation attenuation of the material pile reaches a preset degree; Based on the pre-stored historical data change or process flow rule, it is determined that the critical time point of the predicted material level change is reached.

3. The passive nuclear inventory level gauge measurement range or measurement distance determining system according to claim 1, characterized in that, The computing control module calculates the measurement range of the passive nuclear material level meter at a fixed position relative to the measured container by a preset first algorithm, comprising: Constructing a nuclear radiation field formula based on the nuclear radiation characteristic data, the measurement layout geometric parameters, the material height in the container and the limit radiation value corresponding to the measurement range of the passive nuclear material level meter, wherein the limit radiation value corresponding to the measurement range of the passive nuclear material level meter is the nuclear radiation data obtained by the passive nuclear material level meter at the distance position corresponding to the measurement range, the measurement layout geometric parameters comprise geometric data of the measured container and installation position parameters of the passive nuclear material level meter relative to the measured container, and the measurement range of the passive nuclear material level meter is the relative value of the installation position to the material height in the container or the material height in the container; Calculating the measurement range of the passive nuclear material level meter at a fixed position relative to the measured container based on the nuclear radiation field formula.

4. The passive nuclear inventory level gauge measurement range or measurement distance determining system according to claim 3, characterized in that The measured container is set as a cylindrical structure, and the nuclear radiation field formula in the first algorithm is: ； wherein, I H r h are the limit radiation values corresponding to the measuring range of the passive nuclear level meter, β is the nuclear radiation characteristic data, h is the material height in the container, r is the radius of the bottom surface of the cylindrical container, H is the height difference between the installation position of the level meter and the material in the container, μ is the radiation body linear attenuation coefficient of the material in the measured container, sec is the secant function in the trigonometric function, csc is the cosecant function in the trigonometric function, and the installation position parameter of the passive nuclear level meter relative to the measured container is defined as H sum and satisfies H sum h H ; the measuring range of the passive nuclear level meter is defined as the height of the material in the container h or the height difference between the installation position of the level meter and the material in the container H ;​​​​​ The measured container is projected laterally, and the vertical axis where the level gauge is located is the central axis of the projection. The installation position of the level gauge is defined as point O. The endpoints of the lower side of the rectangular projection of the material in the measured container are defined as points A and B. One endpoint of the upper side is defined as point C. The moving point on the edge contour of the projection is defined as point X. θ 1 is defined as half the angle between rays OA and OB, θ 2 is defined as the angle between ray OC and the vertical axis where point O is located, θ is defined as the angle between ray OX and the vertical axis where point O is located.

5. The passive nuclear inventory level gauge measurement range or measurement distance determining system according to claim 4, characterized in that The nuclear radiation characteristic data is calculated by the following formula: β = κcρ / μ wherein, κ is the radiation constant, c is the content of radioactive material in the measured container, ρ is the bulk density of the radioactive material in the measured container.

6. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 4, wherein, The detection position height of the seed identification correction instrument is set as the installation height of the level meter, I H r h The nuclear radiation data detected by the passive nuclear level meter in real time​​​ The pre-measured installation height of the level gauge relative to the container to be measured is H sum ; Will h = H sum - H Substituting the values ​​into the nuclear radiation field formula, the height difference between the installation location of the level gauge and the material height inside the container being measured is calculated. H As a real-time level gauge measurement range; or, to... H = H sum - h Substituting the nuclear radiation field formula, the height of the material inside the container is calculated. h , as a real-time level gauge measurement range.

7. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 1, wherein, The calculation control module calculates the measurement distance of the passive nuclear material level gauge to the reference material by a preset second algorithm, including: A preset reference material; A preset pre-calculated or measured maximum detection distance of the passive nuclear material level gauge to the reference material; Real-time relative material species values of the reference material are obtained in real time; Based on a relationship function constructed among the measurement distance of the passive nuclear material level gauge to the reference material, the maximum detection distance of the reference material, and the real-time relative material species values, the measurement distance of the passive nuclear material level gauge to the reference material is calculated, wherein the real-time relative material species values are defined as the ratio of the nuclear radiation characteristic data of the real-time reference material detected by the material species identification correction instrument to the nuclear radiation characteristic data of the reference material.

8. The passive nuclear inventory level gauge measurement range or measurement distance determining system according to claim 7, characterized in that The relationship function among the measurement distance of the passive nuclear material level gauge to the real-time reference material, the maximum detection distance of the reference material, and the relative material species values is constructed as: R 2= R 1× wherein, R 2 is the measured distance of the level gauge to the real-time reference material, R 1 is the maximum detection distance of the reference material measured or calculated in advance; P is the real-time relative material value of the real-time reference material and the reference material.

9. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 7, wherein, said real-time relative stock value P by The real-time reference material and the reference material are respectively put into the same first special metering tank with the same height, volume or weight, and the nuclear radiation characteristic data of the real-time reference material and the reference material are respectively measured by using the same material identification correction instrument C 2 2 C 1; Relative planting by formula calculation P = C 2 / C 1.

10. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 9, wherein, nuclear radiation characteristic data of the reference material C 1 maximum detection distance of the reference material R 1 is stored as a calibration parameter; The system further includes a second special metering tank controllably communicated with the measured container; in response to the requirement of the calculation control module for calculating the measurement distance of the passive nuclear material level gauge to the reference material, the same height, volume or weight of material as the reference material is extracted from the measured container as the real-time reference material and discharged into the second special metering tank; The second special metering tank is further provided with a nuclear radiation characteristic data detector configured to detect the nuclear radiation characteristic data released by the real-time reference material in the second special metering tank C 2's material identification correction instrument.

11. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 7, wherein, The maximum detection distance of the reference material is measured by the following method: The nuclear radiation data of the reference material is measured by the passive nuclear material level gauge; The passive nuclear material level gauge is moved to find the limit position where the nuclear radiation measurement result changes abruptly; The nearest distance from the limit position to the reference material is measured as the maximum detection distance of the reference material.

12. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 7, wherein, The maximum detection distance of the reference material is calculated by the following method: determining a current detection distance of the passive nuclear inventory level meter from a reference inventory R 11 ; detecting nuclear radiation data emitted by the reference material I 11 ; The maximum detection distance of the reference material is calculated by the following formula R 1: R 1= R 11 × wherein, I 1represents the limit radiation value corresponding to the measurement range of the passive nuclear material level gauge.

13. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 1, wherein, The calculation control module calculates the measurement range of the passive nuclear material level gauge or the measurement distance of the passive nuclear material level gauge to the reference material by a fitting function.

14. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 13, wherein, The calculation control module calculates the measurement range of the passive nuclear material level gauge by a fitting function, and the fitting function is the following formula: L = a n ×q n + a n-1 ×q n-1 + … a 1×q a 0, wherein, L is a measurement range, q is a nuclear radiation characteristic data of a material to be measured, a 0 to a n is a polynomial coefficient, a n ≠ 0, n ≥ 2; Alternatively, the calculation control module calculates the measurement distance of the passive nuclear material level gauge to the reference material by a fitting function, and the fitting function is the following formula: L = (1 μ ) x ln ([q x V x A ] / L I ) + K D , wherein, L L is the measurement distance of the passive nuclear material level meter to the reference material, q is the nuclear radiation characteristic data of the material to be measured, V is the quantity data of the reference material, I L is the limit radiation value corresponding to the range of the passive nuclear material level meter, μ is the linear attenuation coefficient, A is the calibration coefficient for correcting the deviation between the theoretical model and the actual measurement system, D is the correction constant for error compensation; Alternatively, the calculation control module calculates the maximum detection distance of the passive nuclear material level meter to the reference material by fitting function, and calculates the measurement distance of the passive nuclear material level meter to the reference material by the following formula: R 2= R 1× , wherein, R 2 is the measurement distance of the material level meter to the reference material, P is the real-time relative material value of the real-time reference material and the reference material, R 1 is the maximum detection distance of the reference material, wherein the fitting function for calculating the maximum detection distance of the reference material is any one of the following formulas: R 1= b n ×V n + b n-1 ×V n-1 +…+ b 1×V+ b 0, wherein R 1 is the maximum detection distance of the level meter to the reference material, V is the quantity data of the reference material, b 0 to b n is a polynomial coefficient, b n ≠0, n ≥2; or, R 1= c n × H ref n + c n-1 × H ref n-1 +…+ c 1× H ref + c 0, wherein, R 1 is the maximum detection distance to the reference material, H ref is the height data of the reference material, c 0 to c n is a polynomial coefficient, c n ≠0, n ≥2.

15. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 13, wherein, The calculation control module calculates the measurement range of the passive nuclear material level gauge by a preset fitting function, including: A fitting function between the measurement range of the passive nuclear material level gauge at a fixed position of the measured container and the nuclear radiation characteristic data of the material to be measured is constructed; A measurement test is performed on the material in the measured container to obtain test data including the measurement range and the nuclear radiation characteristic data; Based on the test data, the coefficients in the fitting function are determined; The nuclear radiation characteristic data of the current material to be measured is detected by the material species identification correction instrument, and is substituted into the fitting function with the determined coefficients to obtain the corresponding measurement range.

16. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 15, wherein, The fitting function between the measurement range and the nuclear radiation characteristic data is a high-order polynomial: L a n ×q n + a n-1 ×q n-1 +…+ a 1×q+ a 0, where, L is a measurement range, q is a nuclear radiation characteristic data of a material to be measured, a n ≠0, n ≥2; Based on the test, a plurality of groups of test data of the associated measurement range and the nuclear radiation characteristic data are obtained; performing data fitting on the high order polynomial to determine polynomial coefficients a 0 to a n .

17. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 13, wherein, The calculation control module calculates the measurement distance of the passive nuclear material level meter to the reference material by the following formula: R 2= R 1× , wherein, R 2 is the measurement distance of the material level meter to the reference material, P is the real-time relative material value of the real-time reference material and the reference material, R 1 is the maximum detection distance of the reference material, which is obtained by the following way: The computing control module calculates the maximum detection distance of the passive nuclear material level meter to the reference material through a preset fitting function, including: A fitting function between the maximum detection distance of the passive nuclear material level meter to the reference material and the quantity data of the reference material is constructed, the quantity data of the reference material being one or more of height, volume and weight; A measurement test is performed on the material to obtain a plurality of sets of test data of the maximum detection distance of the reference material and the quantity data of the reference material; Based on the test data, coefficients in the fitting function are determined; The quantity data of the current reference material is obtained and substituted into the fitting function with the determined coefficients to obtain the corresponding maximum detection distance of the reference material.

18. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 17, wherein, The fitting function between the maximum detection distance of the passive nuclear material level meter to the reference material and the quantity data of the reference material is a high-order polynomial: R 1= b n ×V n + b n-1 ×V n-1 + … b 1×V+ b 0, wherein R 1 is the maximum detection distance of the level meter to the reference material, and V is the quantity data of the reference material, b n ≠0, n ≥2; Based on the test, a plurality of sets of test data of the maximum detection distance of the reference material and the quantity data of the reference material are obtained; performing data fitting on the high order polynomial to determine polynomial coefficients b 0 to b n .

19. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 13, wherein, The computing control module calculates the measuring distance of the passive nuclear material level meter at the fixed position of the measured container to the reference material by the following formula: R 2= R 1× , wherein, R 2 is the measuring distance of the material level meter to the reference material, P is the real-time relative material value of the real-time reference material and the reference material, R 1 is the maximum detection distance of the reference material, which is obtained by the following way: The computing control module calculates the maximum detection distance of the passive nuclear material level meter to the reference material in the measured container through a preset fitting function, including: A fitting function between the maximum detection distance of the passive nuclear material level meter to the reference material and the height data of the reference material is constructed; A measurement test is performed on the material to obtain test data including the maximum detection distance and the height data of the reference material; Based on the test data, coefficients in the fitting function are determined; The height of the reference material in the fitting function with the determined coefficients is replaced by the difference between the installation height of the passive nuclear material level meter and the maximum detection distance to obtain a new function; The current installation height of the passive nuclear material level meter is substituted into the new function to calculate the corresponding maximum detection distance of the reference material.

20. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 19, wherein, The fitting function between the maximum detection distance of the passive nuclear material level meter to the reference material and the height data of the reference material is a high-order polynomial: R 1= c n x H ref n + c n-1 x H ref n-1 + …+ c 1x H ref + c 0, wherein R 1 is the maximum detection distance of the reference material, H ref is the height data of the reference material, c n ≠ 0, n ≥ 2; Based on the test, a plurality of sets of test data of the maximum detection distance of the reference material and the height data of the reference material are obtained; performing data fitting on the high order polynomial to determine polynomial coefficients c 0 to c n ; The passive nuclear level gauge is defined by the installation height of the fixed position relative to the measured container H sum , based on H ref = H sum - R 1, a new function is obtained as a function of the maximum detection distance of the reference material: R 1= c n ×( H sum - R 1) n + c n-1 ×( H sum - R 1) n-1 + … c 1×( H sum - R 1)+ c 0.

21. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 13, wherein, The calculation control module calculates the measurement distance of the passive nuclear material level meter to the reference material by the following formula: R 2= R 1× , wherein, R 2 is the measurement distance of the material level meter to the reference material, P is the real-time relative material value of the real-time reference material and the reference material, R 1 is the maximum detection distance of the reference material, which is obtained by the following way: The fitting function between the maximum detection distance of the reference material and the height data of the reference material for constructing the passive nuclear material level meter is R 1= c n × H ref n + c n-1 × H ref n-1 + ... + c 1× H ref + c 0, wherein R 1 is the maximum detection distance of the reference material, H ref is the height data of the reference material, c n ≠ 0, n ≥ 2; A measurement test is performed on the material to obtain test data including the maximum detection distance and the height data of the reference material; determining coefficients in a fitting function based on the test data c 0 to c n ; The height data of the current reference material is obtained and substituted into the fitting function with the determined coefficients to obtain the maximum detection distance of the reference material.

22. The passive nuclear inventory tank level gauge measurement range or measurement distance determining system of claim 13, wherein, The computing control module calculates the measurement distance of the passive nuclear material level meter to the reference material through a preset fitting function, including: A fitting function between the measurement distance of the passive nuclear material level meter to the reference material and the quantity data of the reference material and the nuclear radiation characteristic data is constructed, the quantity data of the reference material being one or more of height, volume and weight; A measurement test is performed on the reference material to obtain test data including the measurement distance of the passive nuclear material level meter to the reference material, the quantity data of the reference material and the nuclear radiation characteristic data; Based on the test data, coefficients in the fitting function are determined; The nuclear radiation characteristic data of the current material to be measured is detected by using the material type identification correction instrument, the quantity data value of the reference material is selected, and the fitting function with the determined coefficients is substituted to obtain the corresponding measurement distance.

23. The passive nuclear inventory tank gauge measurement range or measurement distance determining system of claim 22, wherein, The fitting function is the following polynomial: L = (1 μ ) x ln ([q x V x A ] / V I ) + K D , wherein, L is a measurement distance of the passive nuclear material level meter to the reference material, q is nuclear radiation characteristic data of the material to be measured, V is quantity data of the reference material, I is a limit radiation value corresponding to the measurement range of the passive nuclear material level meter, μ is a linear attenuation coefficient, A is a calibration coefficient for correcting the deviation between the theoretical model and the actual measurement system, D is a correction constant for compensating for errors; Based on the test, a plurality of groups of associated measured distances are obtained L , reference material quantity data V, nuclear radiation characteristic data q; Based on the data obtained from the experiment, the linear decay coefficient in the fitting function is determined μ、 a correction constant D and a calibration coefficient A .

24. The passive nuclear inventory level gauge measurement range or measurement distance determining system according to any one of claims 1 to 23, characterized in that The passive nuclear material level meter for measuring the reference material is served by other types of nuclear radiation measuring devices which have the same nuclear radiation detection performance as the passive nuclear material level meter or whose nuclear radiation detection performance is derived from the nuclear radiation detection performance of the passive nuclear material level meter.

25. The passive nuclear material level gauge measurement range or measurement distance determining system according to any of the claims 1 - 23, characterized by The measured container for testing is served by other containers which have the same structure as the measured container or whose structure is a scaled-up or scaled-down structure of the measured container.

26. The passive nuclear inventory level gauge measurement range or measurement distance determining system of claim 1, wherein, The system further comprises the third-party device triggered by the computing control module to perform the measurement step, which includes a material level detection device, a track determined relative to the position of the measured container, and a nuclear radiation sensor capable of being driven to move on the track; Based on the material level detection device, the actual height of the material in the current measured container is provided, and the nuclear radiation sensor moves to a critical position where the detection data is zeroed to obtain the measurement range of the nuclear radiation sensor; Based on the range conversion relationship between the nuclear radiation sensor and the passive nuclear material level meter, the measurement range of the passive nuclear material level meter is converted.

27. The passive nuclear inventory tank level gauge measurement range or measurement distance determining system of claim 26, wherein, The material level detection device includes a visual recognition device, a radar device, an ultrasonic device, a weighing device, or a touch switch capable of moving downward relative to the measured container.

28. The passive nuclear material level gauge measurement range or measurement distance determining system according to any of claims 1 to 23 or claim 26 or claim 27, characterized in that, Further comprising a display device and / or an output module, wherein the display device is configured to display the measurement range of the current passive nuclear material level meter or the measurement distance of the passive nuclear material level meter to the reference material, and / or display the material level measurement result of the passive nuclear material level meter; The output module is configured to send the measurement range and / or the material level measurement result to a remote client through wired and / or wireless output.

29. The passive nuclear inventory tank level gauge measurement range or measurement distance determining system of claim 28, wherein, The display device is integrated with one of the passive nuclear material level meter, the material type identification correction instrument, and the computing control module, or is wired or wirelessly connected to the passive nuclear material level meter, the material type identification correction instrument, and / or the computing control module.

30. The passive nuclear material level gauge measurement range or measurement distance determining system according to any of claims 1 to 23 or claim 26 or claim 27, characterized in that, If the material level value generated by the passive nuclear material level meter is less than or equal to a preset material level threshold value, or the nuclear radiation data measured by the passive nuclear material level meter is less than or equal to a preset nuclear radiation threshold value, the passive nuclear material level meter outputs prompt information in a preset format, and the prompt information includes the current measurement range information.

31. A method of determining a measurement range or a measurement distance for a passive nuclear material level gauge, characterized in that The measurement range of the passive nuclear material level meter at the fixed position relative to the measured container or the measurement distance of the passive nuclear material level meter to the reference material is determined by the following steps: The material type identification correction instrument is used to detect the nuclear radiation characteristic data released by the material in the measured container; In response to a preset trigger condition, at least one of the following operations is performed: According to a preset algorithm, the measurement range of the passive nuclear material level meter or the measurement distance of the passive nuclear material level meter to the reference material is calculated; The third-party device is controlled to perform measurement to obtain the measurement range of the passive nuclear material level meter or the measurement distance of the passive nuclear material level meter to the reference material; Determine the measurement range of the passive nuclear material level meter corresponding to the nuclear radiation characteristic data or the measurement distance of the passive nuclear material level meter to the reference material corresponding to the nuclear radiation characteristic data by querying the preset mapping relationship.

32. The passive nuclear inventory level gauge measurement range or measurement distance determining method of claim 31, wherein, The preset algorithm is any one of the following first algorithm, second algorithm, third algorithm, and fourth algorithm: The first algorithm is to construct a nuclear radiation field formula based on nuclear radiation characteristic data, measurement layout geometric parameters, container material height, and limit radiation values corresponding to the measurement range of the passive nuclear material level meter, wherein the limit radiation values corresponding to the measurement range of the passive nuclear material level meter are nuclear radiation data obtained by the passive nuclear material level meter at a distance position corresponding to the measurement range, the measurement layout geometric parameters include geometric data of the measured container and installation position parameters of the passive nuclear material level meter relative to the measured container, the measurement range of the passive nuclear material level meter is determined, and the relative value of the installation position to the material in the measured container is determined, or the material height in the measured container is the measurement range of the material level meter; The second algorithm is to prepare a reference material, pre-calculate or measure the maximum detection distance of the reference material and the real-time relative material value of the real-time reference material and the reference material, and construct a relationship function among the measurement distance of the passive nuclear material level meter to the reference material, the maximum detection distance of the reference material, and the real-time relative material value, wherein the real-time relative material value is defined as the ratio of the nuclear radiation characteristic data of the real-time reference material detected by the material type identification correction instrument to the nuclear radiation characteristic data of the reference material; The third algorithm is to construct a fitting function between the measurement range of the passive nuclear material level meter at the fixed position of the measured container and the nuclear radiation characteristic data of the material to be measured, or a fitting function between the measurement distance of the passive nuclear material level meter to the reference material and the quantity data of the reference material, or a fitting function among the measurement distance of the passive nuclear material level meter to the reference material, the quantity data of the reference material, and the nuclear radiation characteristic data; perform a material measurement test, and determine the coefficients in the fitting function based on the test data; and calculate the measurement range of the corresponding material level meter or the measurement distance of the material level meter to the reference material using the fitting function with the determined coefficients. The fourth algorithm is a fitting function between the maximum detection distance of the reference material and the quantity data of the reference material for constructing the passive nuclear material level meter; a material measurement test is performed, and the coefficients in the fitting function are determined based on the test data; the maximum detection distance of the passive nuclear material level meter for the reference material is calculated using the fitting function with the determined coefficients; and the measurement distance of the passive nuclear material level meter for the reference material is calculated using the formula: R 2= R 1× , wherein, R 2 is the measurement distance of the material level meter for the reference material, P is the real-time relative material value of the real-time reference material and the reference material, R 1 is the maximum detection distance of the reference material.

33. The passive nuclear inventory level gauge measurement range or measurement distance determining method of claim 32, wherein, The reference material is acted by the material outside the range edge, or by the material within the range; When calculating the installation position of the passive nuclear material level meter on the container to the full material at the bottom of the container or the upward measurement range or measurement distance of the passive nuclear material level meter, the medium of the measurement space is the material.

34. A passive nuclear material level gauge material level measurement method, characterized by The steps include: After determining the current measurement range of the passive nuclear material level meter using the passive nuclear material level meter measurement range or measurement distance determination system according to any one of claims 1 to 30, the passive nuclear material level meter further includes a step of calculating the material level height of the material entering the measurement range using the current measurement range: calculating a relative material level value of the material in the measuring range based on a difference between a measurement value of the passive nuclear material level gauge and a preset empty tank value of the container, a difference between a real-time full tank value and the preset empty tank value of the container, and the measuring range, the relative material level value being a material level value of the material measured from an edge of the measuring range in the measuring range of the passive nuclear material level gauge; if a difference between the relative installation height of the passive nuclear material level gauge and the measuring range is greater than or equal to 0, calculating a sum of the relative material level value and the difference between the relative installation height of the passive nuclear material level gauge and the measuring range to obtain a material level value of the material in the container.

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