System and method for determining measuring range or measuring distance of passive nucleon level gauge and material level measuring method

Abstract

The invention discloses a system and method for determining the measuring range or measuring distance of a passive nucleon level gauge and a material level measuring method, and the system is used for determining the measuring range of the passive nucleon level gauge at a fixed position relative to a measured container or the measuring distance of the passive nucleon level gauge to a reference material. The system comprises a passive nucleon level gage, a material type identification correction instrument and a calculation control module, wherein the material type identification correction instrument is configured to detect nuclear radiation characteristic data released by materials in a measured container; the calculation control module calculates a measurement range or a measurement distance according to a preset algorithm in response to the condition that the material nuclear radiation characteristic data output by the material type identification correction instrument meets the condition; or the calculation control module controls the third-party equipment to execute measurement so as to obtain the measurement range or the measurement distance; or the calculation control module determines the measuring range or the measuring distance corresponding to the nuclear radiation characteristic data by inquiring a preset mapping relation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of non-contact level measurement, in particular to a passive nuclear level gauge measurement range or measurement distance determination system, determination method and level measurement method. BACKGROUND

[0002] The passive nuclear level gauge is mainly used for measuring the gamma rays released by the radioactive substances contained in the materials in the coal ash of the thermal power plant or the metallurgical dust collector of the steel plant, and is used for measuring the level of the materials in the container. Since the passive nuclear level gauge has the characteristics of completely non-contact measurement, especially it can continuously monitor the level of the materials in the container, it is widely used in thermal power enterprises or industrial scenes such as steel.

[0003] Since the passive nuclear level gauge measures the radioactive substances contained in the materials, and as we all know, the radioactive substances contained in the materials are not constant, but frequently change. In order to ensure the accuracy of the passive nuclear level gauge measurement, an external material identification device must be used to identify the characteristics of the radioactive substances contained in the materials in real time and correct it to ensure the accuracy of the measurement. Alternatively, a multi-probe passive nuclear level gauge or a system composed of multiple passive nuclear level gauges is used to correct the material change under certain conditions, which ensures the accuracy of the level to a certain extent.

[0004] Since the characteristics of the radioactive materials of the materials change, it means that the nuclear radiation released by the same materials is different under different material conditions. For the same reason, the measurement range of the passive nuclear level gauge for the same material is also different.

[0005] For the passive nuclear level gauge used for measuring at a fixed position, in the same container, the maximum detection radius or detection distance is completely different when measuring different radioactive characteristic materials.

[0006] The passive nuclear material level meter is also different in measuring range for the same material, or in the same container, the maximum detection radius or detection distance is completely different when measuring different radioactive characteristic materials, and this important problem has not been concerned in the prior art, or the method for calculating and expressing the measuring range of the passive nuclear material level meter has not been found. For example, in the Chinese invention patent application with the publication number CN119223400A, it is recorded that "the minimum material level scale of the passive nuclear radiation material level meter corresponds to different materials, and the detection range of the passive nuclear radiation material level meter is different, that is, R is different under different material conditions, but since the material nuclear radiation decays in space according to the inverse square law, the detection ranges R of different materials are close when the material values are close, and in order to facilitate calculation, the application presets that the R of different materials is the same", even if it is realized that the material radioactive characteristic changes, but only the same measuring range under different material radioactive characteristic conditions can be fixedly set to deal with the measuring range problem.

[0007] In the prior art, especially when the relative material level algorithm based on the relative parameters is used to calculate the material level, the measuring range of the passive nuclear material level meter is not considered in the operation of the passive nuclear material level meter, the actual measuring range of the passive nuclear material level meter is not considered due to the change of the coal type, and the real-time detection range of the passive nuclear material level meter is not considered in the actual application. The existing passive nuclear material level meter often causes a serious misunderstanding to the operator that the material is measured from the 0 position of the container. In fact, many passive nuclear material level meters are analog output, and the user often defines 4mA as a fixed value, such as 0 or 0%. Even with the material type identification correction instrument, the algorithm in the passive nuclear material level meter is to calculate the material level in the container from the 0 position.

[0008] In the relative material level algorithm of the existing passive nuclear material level meter, the measuring inaccuracy problem caused by the change of the material radioactive characteristic is not considered, and it is defaulted that the actual measuring range of a passive nuclear material level meter is the same regardless of the material radioactive characteristic. When the material radioactive characteristic deviates greatly, the material level accuracy is extremely poor.

[0009] Under the prior art, the passive nuclear material level meter or the matching equipment of the passive nuclear material level meter does not provide the real-time detection range information of the passive nuclear material level meter to the operator, and under the condition that the material radioactive characteristic changes continuously, the operator cannot know the real-time detection range of the passive nuclear material level meter under different material conditions. It is easy to understand that the 0 material level is the real empty bin, instead of being outside the detection range of the passive nuclear material level meter. The prior art brings confusion and misunderstanding to the operator.

[0010] The prior art lacks a passive nuclear material level meter range measurement method, and the passive nuclear material level meter cannot automatically determine the measurement range, and the prior art has obvious deficiencies.

[0011] The disclosure of the above background art is only used to assist in understanding the concept and technical solutions of the present application, and it does not necessarily belong to the prior art of the present application, nor does it necessarily give technical teaching; in the absence of explicit evidence that the above content has been disclosed before the filing date of the present application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0012] The purpose of the present application is to provide a system that can automatically determine the real-time measurement range of a passive nuclear material level meter or the real-time detection distance of a reference material in the actual operation of the passive nuclear material level meter; completely solve the problem that the existing manual setting of the fixed range cannot meet the real-time and random changes of the material level in the process flow; solve the problem of the lack of real-time measurement range in the application of the existing passive nuclear material level meter; solve the problem that the fixed setting of the measurement range of the passive nuclear material level meter leads to inaccurate material level generated by the passive nuclear material level meter; alert the user by displaying the measurement range of the passive nuclear material level meter or the detection distance of the reference material, and better ensure production safety.

[0013] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0014] A passive nuclear material level meter measurement range or measurement distance determination system for determining the measurement range of a passive nuclear material level meter at a fixed position relative to a measured container or the measurement distance of a reference material by the passive nuclear material level meter, the system comprising a passive nuclear material level meter, a material type identification correction instrument and a calculation control module, wherein the material type identification correction instrument and the passive nuclear material level meter are respectively connected in communication with the calculation control module;

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

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

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

[0018] The calculation 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 reference material by the passive nuclear material level meter;

[0019] 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.

[0020] Further, any one of the above technical solutions or a combination of the above technical solutions, the preset trigger condition comprises at least one of the following:

[0021] receiving an external signal;

[0022] after a preset timing duration;

[0023] at a preset time;

[0024] receiving a signal that the passive nuclear material level meter accesses the system;

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

[0026] The change of the nuclear radiation characteristic data output by the material species identification correction instrument at least twice exceeds a preset condition;

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

[0028] The measurement result of the passive nuclear material level meter represents that the radiation attenuation of the material pile reaches a preset degree;

[0029] Based on the pre-stored historical data change or process flow rule, it is determined that the critical time point of predicting the material level change is reached.

[0030] Further, any one of the above technical solutions or a combination of the above technical solutions, 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:

[0031] Construct a nuclear radiation field formula based on nuclear radiation characteristic data, measurement layout geometric parameters, container material height, and 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 measurement range corresponding distance position, 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 the relative value of the installation position to the container material, or the container material height;

[0032] Calculate 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.

[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] Where I(H,r,h) is the limiting radiation value corresponding to the passive nuclear level gauge range, β is the nuclear radiation characteristic data, h is the material height inside the container, r is the bottom radius of the cylindrical container, and H is the height difference between the installation position of the level gauge and the material height inside the container. μ H is the radiometric attenuation coefficient of the material inside the measured container, sec is the secant function in trigonometric functions, csc is the cosecant function in trigonometric functions, and the installation position parameter of the passive nuclear level gauge relative to the measured container is defined as H. sum and satisfy H sum =h + H; The measurement range of the passive nuclear level gauge is defined as the height h of the material inside the container or the difference H between the installation position of the level gauge and the height of the material inside the container;

[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, and one of the upper endpoints is point C. The moving point on the projection edge contour is point X. θ1 is defined as half of the angle between rays OA and OB, θ2 is defined as the angle between ray OC and the vertical axis where point O is located, and θ is defined as the angle between ray OX and the vertical axis where point O is located.

[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, where κ is the radiation constant, c is the content of radioactive material in the container being measured, ρ is the bulk density of the radioactive material in the container being measured, and μ is the radiometric attenuation coefficient of the material in 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, and I(H,r,h) is the nuclear radiation data detected in real time by the passive nuclear level gauge;

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

[0041] Let h=H sumSubstituting H into the nuclear radiation field formula, the height difference H between the installation position of the level gauge and the material inside the measured container is calculated, and this difference is used as the real-time measurement range of the level gauge; or, H = H sum Substituting -h into the nuclear radiation field formula, the height h of the material inside the container is calculated and used as the 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] R2=R1× Where R2 is the measurement distance of the level gauge to the real-time reference material, R1 is the maximum detection distance of the reference material obtained by pre-measurement or calculation, and P is the real-time relative material type value between the real-time reference material and the reference material.

[0049] Furthermore, following any one or a combination of the aforementioned technical solutions, the real-time relative material type value P is obtained in the following manner:

[0050] Real-time reference material and reference material of the same height, volume or weight were placed in the same dedicated metering tank. The nuclear radiation characteristic data C2 of the real-time reference material and the nuclear radiation characteristic data C1 of the reference material were measured using the same material type identification and correction instrument.

[0051] The relative planting density is calculated using the formula P = C2 / C1.

[0052] Furthermore, following any one or a combination of the aforementioned technical solutions, the nuclear radiation characteristic data C1 of the reference material and the maximum detection distance R1 of the reference material are stored as calibration parameters;

[0053] The system also includes a 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 dedicated metering tank;

[0054] The dedicated metering tank is also equipped with a material type identification and correction device configured to detect the nuclear radiation characteristic data C2 released by the real-time reference material in the dedicated metering tank.

[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 R between the passive nuclear level gauge and the reference material. 11 ;

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

[0062] The maximum detection distance R1 of the reference material is calculated using the following formula: R1 = R 11 × Wherein, I1 represents the limiting radiation value corresponding to the passive nuclear 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 +…+a1×q+a0, where L is the measurement range, q is the nuclear radiation characteristic data of the material to be measured, and a0 to a n Let a be the polynomial coefficient. 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, where L is the measurement distance of the passive nuclear level gauge 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 is the limiting radiation value corresponding to the passive nuclear level gauge range, μ is the linear attenuation coefficient, A is the calibration coefficient used to correct the deviation between the theoretical model and the actual measurement system, and D is the correction constant used to compensate for the error;

[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: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is the maximum detection distance of the reference material. The fitting function for calculating the maximum detection distance of the reference material is any of the following formulas:

[0069] R1=b n ×V n +b n-1 ×V n-1 +…+b1×V+b0, where R1 is the maximum detection distance of the level gauge to the reference material, V is the quantity data of the reference material, and b0 to b… n b are the polynomial coefficients. n ≠0, n≥2; or, R1=c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, where R1 is the maximum detection distance for the reference material, H refFor reference material height data, c0 to c n c are the polynomial coefficients. 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 +…+a1×q+a0, where L is the measurement range, q is the nuclear radiation characteristic data of the material to be measured, and 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 a0 to a0. 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: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is 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 to 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, following 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] R1=b n ×V n +b n-1 ×V n-1 +…+b1×V+b0, where R1 is the maximum detection distance of the level gauge to the reference material, V is the quantity data of the reference material, and 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 b0 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 on the measured container to the reference material using the following formula: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is 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] R1 = c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, where R1 is the maximum detection distance for the reference material, 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 c0 to c1. 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 -R1, resulting in a new function used to calculate the maximum detection distance of the reference material: R1 = c n ×(H sum -R1) n +c n-1 ×(H sum -R1) n-1 +...+c1×(H) sum -R1)+c0.

[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: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is 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 R1 = c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, where R1 is 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 c0 to c in the fitting function. 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, where L is the measurement distance of the passive nuclear level gauge 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 is the limiting radiation value corresponding to the passive nuclear level gauge range, μ is the linear attenuation coefficient, A is the calibration coefficient used to correct the deviation between the theoretical model and the actual measurement system, and D is the correction constant used to compensate for the error;

[0113] Based on the experiment, multiple sets of associated measurement distance L, reference material quantity data V, and nuclear radiation characteristic data q were obtained;

[0114] Based on the experimental data, the linear attenuation coefficient μ, correction constant D, and calibration coefficient A in the fitting function are determined.

[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 the formula to calculate the measurement distance of the passive nuclear level gauge to the reference material: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is 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 passive nuclear level gauge method for measuring level 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 4A 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 9 A 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 passive nuclear level gauge measurement range or measurement distance determination system 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] Where I(H,r,h) is the limiting radiation value corresponding to the passive nuclear level metering range, β is the nuclear radiation characteristic data, and h is the material height 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 4As 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 measured container, fixedly above the material, or it can be installed on the outer wall of the measured container. Points A and B are the lower endpoints of the rectangular projection of the material inside the measured container, and point C is one of the upper endpoints. θ1 is defined as half the angle between rays OA and OB. Figure 4 In this context, ∠AOX0 and θ2 are defined as the angle between ray OC and the vertical axis containing point O. Figure 4 In the formula, ∠COX0, sec is the secant function in trigonometric functions, and csc is the cosecant function in trigonometric functions;

[0198] Assuming the height of the material inside the container is h, the radius of the bottom surface of the cylindrical container is r, and H is the height difference between the installation position of the level gauge and the height of the material inside the container, the installation position parameter of the passive nuclear level gauge relative to the container being measured is defined as H. sum Then H is satisfied sum =h + H; The measurement range of the passive nuclear level gauge is defined as the height h of the material inside the container or the difference H between the installation position of the level gauge and the height of the material inside the container;

[0199] A side projection is made onto the container being measured. The moving point on the projection edge contour is called point X. θ is 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, the formula for calculating the nuclear radiation characteristic data β is as follows:

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

[0202] The detection position height of the material type identification and correction instrument is set to the installation height of the level gauge, and I(H,r,h) is the nuclear radiation data detected in real time by the passive nuclear level gauge;

[0203] It should be noted that I(H,r,h) in the formula represents the nuclear radiation value obtained from the measurement point in the measurement space, implying 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, ranging from large to 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-limited nuclear radiation data measured by the passive nuclear level gauge is 20, then the range-limited 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 as H. sum ;

[0205] Let h=H sum Substituting H into the nuclear radiation field formula, the height difference H between the installation position of the level gauge and the material inside the measured container is calculated, and this value is used as the real-time measurement range of the level gauge; alternatively, H = H sum Substituting -h into the nuclear radiation field formula, the height h of the material inside the container is calculated and used as the real-time measurement range of the level gauge.

[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 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 relationship function between the passive nuclear level gauge's measurement distance to the real-time reference material (denoted as R2), the maximum detection distance to the reference material (denoted as R1), and the real-time relative material type value between the real-time reference material and the reference material (denoted as P) is constructed as follows:

[0217] R2=R1× Where R2 is the measurement distance of the level gauge to the real-time reference material, R1 is the maximum detection distance of the reference material obtained by pre-measurement or calculation, and P is the real-time relative material type value between the real-time reference material and the reference material.

[0218] The real-time relative material type value P 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, and 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 dedicated metering tank. The nuclear radiation characteristic data C2 of the real-time reference material and the nuclear radiation characteristic data C1 of the reference material were measured using the same material type identification and correction instrument.

[0220] The relative planting density is calculated using the formula P = C2 / C1.

[0221] After obtaining the nuclear radiation characteristic data C1 and the maximum detection distance R1 of the reference material in a single measurement, they are stored as calibration parameters. In other words, the relative material seeding P changes with the nuclear radiation characteristic data C2 released by the real-time reference material. That is, the real-time relative material seeding P is calculated by acquiring the real-time nuclear radiation characteristic data C2. The specific method for acquiring the real-time nuclear radiation characteristic data C2 is as follows:

[0222] The system also includes a dedicated metering tank, which is controllably connected to the container being measured; in response to the calculation control module's requirement to calculate the measurement distance of the passive nuclear level gauge to the reference material (i.e., the requirement to calculate the real-time relative material planting P), material of 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 dedicated metering tank; the dedicated metering tank is also equipped with a material type identification and correction instrument configured to detect the nuclear radiation characteristic data C2 released by the real-time reference material in the dedicated metering tank.

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

[0224] Figure 6 The steps shown are to obtain the maximum detection distance R1 of the reference material by measurement:

[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 R1 of the reference material:

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

[0230] S322: Detection of nuclear radiation data released by reference materials I 11 ;

[0231] S323: Calculate the maximum detection distance R1 of the reference material using the following formula: R1 = R 11 × Where I1 represents the limiting radiation value corresponding to the passive nuclear level metering range.

[0232] The maximum detection distance R1 of the reference material is obtained in advance by measurement or calculation, and then substituted into R2 = R1 × 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 a0 to a0 from other sources. n Fitting function: L=a n ×q n +a n-1 ×q n-1 +…+a1×q+a0, where L is the measurement range of the passive nuclear level gauge relative to the fixed position of the measured container, q is the nuclear radiation characteristic data of the material to be measured in the measured container, and a0 to a… n Let a be the polynomial coefficient. 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 L of the passive nuclear level gauge relative to the fixed position of the measured container.

[0235] The second implementation of the first fitting embodiment involves constructing a fitting function between the measurement range L of the passive nuclear level gauge at a fixed position in the container being measured and the nuclear radiation characteristic data q of the material to be measured; conducting a measurement experiment on the material in the container being measured to obtain experimental data including the measurement range and nuclear radiation characteristic data; determining the coefficients in the fitting function based on the experimental data; using a material type identification and correction instrument to detect the nuclear radiation characteristic data of the material to be measured, and substituting it into the fitting function after determining the coefficients 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 +…+a1×q+a0, this function can be modified without creative effort. In order to determine the coefficients in the fitting function, we can obtain the correlation experimental data between the parameters of the fitting function other than the coefficients to be determined based on experiments, and then perform data fitting on the higher-order polynomial to determine the polynomial coefficients.

[0237] The second fitting embodiment: 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, where L is the measurement distance of the passive nuclear level gauge at a fixed position in the measured container 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 is the limiting radiation value corresponding to the passive nuclear level gauge range, μ is the linear attenuation coefficient, A is the calibration coefficient used to correct the deviation between the theoretical model and the actual measurement system, and D is the correction constant used to compensate for the error, where the limiting radiation value I is the performance parameter of the passive nuclear level gauge, V is one or more of the height, volume, and weight of the currently measured reference material, and μ, A, and D are the determined coefficients 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 aforementioned L = (1 / μ) × ln([q × V × A] / I) + D. Implementations corresponding to other functions with simple modifications, without requiring inventive effort, are also within the scope of protection claimed by this invention. Taking L = (1 / μ) × ln([q × V × A] / I) + D as an example, based on experiments, multiple sets of associated measurement distances L, reference material quantity data V, and nuclear radiation characteristic data q are obtained; based on the data obtained from the experiments, the linear attenuation coefficient μ, correction constant D, and calibration coefficient A in the fitting function are determined.

[0240] In response to the trigger action, the current nuclear radiation characteristic data q of the material type identification and correction instrument, the quantity data V of the reference material, and the limiting radiation parameter value I of the passive nuclear level gauge are substituted into the above fitting formula to 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 R2=R1× constructed in the second example Where R2 is the measurement distance of the level gauge to the reference material, and P is the real-time relative material type value between the real-time reference material and the reference material. Unlike the second embodiment, which obtains the maximum detection distance R1 of the reference material through measurement or calculation, the third fitting embodiment uses a fitting formula to obtain the maximum detection distance of the level gauge to 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] R1=b n ×V n +b n-1 ×V n-1 +…+b1×V+b0, where R1 is the maximum detection distance of the level gauge to the reference material, V is the quantity data of the reference material, and b0 to b… n b are the polynomial coefficients. n ≠0, n≥2;

[0244] Or, R1 = c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, where R1 is the maximum detection distance for the reference material, H ref For reference material height data, c0 to c n c are the polynomial coefficients. n ≠0, n≥2.

[0245] Substitute the quantity data V (height, volume, and / or weight) of the reference material into the previous fitting function, or use the height data H of the reference material. ref Substitute the previous fitting function to calculate the maximum detection distance R1 of the level gauge for the reference material, 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 dedicated metering tank as a real-time reference material. This material is then discharged into the dedicated metering tank, and the real-time nuclear radiation characteristic data C2 released by the real-time reference material in the dedicated metering tank is detected using a material type identification correction instrument. Combining this with the nuclear radiation characteristic data C1 of the reference material stored as calibration parameters, the real-time relative material level P = C2 / C1 can be calculated. Furthermore, combining this with the maximum detection distance R1 of the reference material stored as calibration parameters, the measurement distance R2 of the passive nuclear level gauge relative to the fixed position of the container being measured relative to the reference material can be calculated as R2 = R1 × .

[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 R1 = b as described above. n ×V n +b n-1 ×V n-1 +…+b1×V+b0, other implementations corresponding to functions that are simply modified without creative effort also fall within the scope of protection claimed by this invention. For example, R1=b n ×V n +b n-1 ×V n-1 Taking +…+b1×V+b0 as an example, based on experiments, the maximum detection distance R1 of multiple sets of associated level gauges to the reference material and the quantity data V of the reference material are obtained; based on the associated data obtained from the experiments, data fitting is performed on the high-order polynomial to determine the polynomial coefficients b0 to b in the fitting function. 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, calculate the maximum detection distance R1 of the level gauge to the reference material, 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 described again 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 R1 = c as described above. n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, and other implementations corresponding to simple modifications of this function without creative effort also fall within the scope of protection claimed by this invention. For example, R1 = c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref Taking +c0 as an example, based on experiments, the maximum detection distance R1 of multiple sets of associated level gauges to the reference material and the height data H of the reference material were obtained. ref Based on the experimental data and the correlation data obtained from the experiments, data fitting is performed on the high-order polynomial to determine the polynomial coefficients c0 to c in the fitted function. n .

[0253] After determining the fitting function, obtain the height data H of the reference material. ref Substitute this into the previous fitting function to calculate the maximum detection distance R1 of the level gauge for the reference material, 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 the fitting function R1 = c is determined. n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref After +c0 (polynomial coefficients c0 to c) n (This has been determined), defining the installation height H of the passive nuclear level gauge relative to the fixed position of the measured container. sum Based on H ref =H sum -R1, resulting in a new function used to calculate the maximum detection distance of the reference material: R1 = c n ×(H sum -R1) n +cn-1 ×(H sum -R1) n-1 +...+c1×(H) sum -R1)+c0.

[0256] After determining the fitting function, unlike the third implementation of the third fitting example, it is not necessary to measure the height data H of the reference material. ref Given that the installation height of the passive nuclear level gauge at a fixed position relative to the container being measured is H... sum Under these conditions, the maximum detection distance R1 of the reference material can be calculated and stored 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 the formula to calculate the measurement distance of the passive nuclear level gauge to the reference material: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is 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 passive nuclear level gauge pre-sets the nuclear radiation value C measured in the empty and full states of the container being measured. empty and C full The nuclear radiation level C in an empty warehouse empty This refers to the environmental radiation value, specifically the real-time detected nuclear radiation value C. real The radiation level C exceeds the value of nuclear radiation in an empty chamber. empty When 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 height is as follows: Hreal =H max ×(C real -C empty ) / (C full -C empty ), where H real H represents the real-time material level height. max The total height of the container. H relative C represents the relative level value of the material within the measurement range of the passive nuclear level gauge. real C represents the current real-time nuclear radiation value detected by the passive nuclear level gauge. 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 container being measured is defined as L2. In this embodiment, the relative level value of the material within the measurement range of the passive nuclear level gauge is calculated using the current measurement range L1, as follows:

[0319] H relative =L1×(C real -C empty ) / (C full -C empty );

[0320] In the above calculation formula, L1×(C real -C empty ) / (C full -C empty L1 represents the relative material level within the measurement range. Of course, in practice, when L1 and C are obtained or known... 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] If L2-L1≥0, then the material level in the container can be calculated:

[0322] H real =L1×(C real -C empty ) / (C full -C empty ) + (L2 - L1).

[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 system for determining the measurement range or measurement distance of a passive nuclear level gauge, 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, characterized in that, 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; The material type identification and correction instrument is configured to detect the nuclear radiation characteristic data released by the material inside the measured container; In response to a preset triggering condition, the calculation control module is configured to perform at least one of the following operations: 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; 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; 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.

2. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 1, characterized in that, The preset triggering conditions include at least one of the following: Received external signal; After a preset timeout period; Arrive at the preset time; The passive nuclear level gauge connection signal was received; The material type identification and correction instrument outputs material nuclear radiation characteristic data; The nuclear radiation characteristic data output by the material type identification and correction instrument at least twice exceeds the preset condition; The nuclear radiation data or level value measured by the passive nuclear level gauge is higher than a preset threshold. The measurement results of the passive nuclear level gauge indicate that the radiation attenuation of the stockpile has reached a preset level; 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.

3. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 1, characterized in that, The calculation and 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: 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 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. 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.

4. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 3, characterized in that, Assuming the container being measured is a cylindrical structure, the nuclear radiation field formula in the first algorithm is: ； Where I(H,r,h) is the limiting radiation value corresponding to the passive nuclear level gauge range, β is the nuclear radiation characteristic data, h is the material height inside the container, r is the bottom radius of the cylindrical container, H is the height difference between the installation position of the level gauge and the material inside the container, μ is the radiation attenuation coefficient of the material inside the measured container, sec is the secant function in trigonometric functions, and csc is the cosecant function in trigonometric functions. The installation position parameter of the passive nuclear level gauge relative to the measured container is defined as H. sum and satisfy H sum =h + H; The measurement range of the passive nuclear level gauge is defined as the height h of the material inside the container or the difference H between the installation position of the level gauge and the height of the material inside the container; 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, and one of the upper endpoints is point C. The moving point on the projection edge contour is point X. θ1 is defined as half of the angle between rays OA and OB, θ2 is defined as the angle between ray OC and the vertical axis where point O is located, and θ is defined as the angle between ray OX and the vertical axis where point O is located.

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

6. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 4, characterized in that, The detection position height of the material type identification and correction instrument is set to the installation height of the level gauge, and I(H,r,h) is the nuclear radiation data detected in real time by the passive nuclear level gauge; The installation height of the level gauge relative to the container being measured is pre-measured as H. sum ; Let h=H sum Substituting H into the nuclear radiation field formula, the height difference H between the installation position of the level gauge and the material inside the measured container is calculated, and this difference is used as the real-time measurement range of the level gauge; or, H = H sum Substituting -h into the nuclear radiation field formula, the height h of the material inside the container is calculated and used as the real-time level gauge measurement range.

7. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 1, characterized in that, 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: Preset reference materials; The maximum detection distance of the passive nuclear level gauge for the reference material is pre-calculated or measured. Real-time relative material type values ​​between the baseline material and the reference material; 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.

8. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 7, characterized in that, The relationship function between the measurement distance of the passive nuclear level gauge to the real-time reference material, the maximum detection distance of the reference material, and the relative material type value is constructed as follows: R2=R1× Where R2 is the measurement distance of the level gauge to the real-time reference material, R1 is the maximum detection distance of the reference material obtained by pre-measurement or calculation, and P is the real-time relative material type value between the real-time reference material and the reference material.

9. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 7, characterized in that, The real-time relative material type value P is obtained through the following method: Real-time reference material and reference material of the same height, volume or weight were placed in the same dedicated metering tank. The nuclear radiation characteristic data C2 of the real-time reference material and the nuclear radiation characteristic data C1 of the reference material were measured using the same material type identification and correction instrument. The relative planting density is calculated using the formula P = C2 / C1.

10. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 9, characterized in that, The nuclear radiation characteristic data C1 of the reference material and the maximum detection distance R1 of the reference material are stored as calibration parameters; The system also includes a 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 dedicated metering tank; The dedicated metering tank is also equipped with a material type identification and correction device configured to detect the nuclear radiation characteristic data C2 released by the real-time reference material in the dedicated metering tank.

11. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 7, characterized in that, The maximum detection distance of the reference material was measured in the following manner: The passive nuclear level gauge was used to measure the nuclear radiation data of a reference material. Move the passive nuclear level gauge to find the extreme position where its nuclear radiation measurement result changes abruptly; The closest distance from the extreme position to the reference material is measured and used as the maximum detection distance of the reference material.

12. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 7, characterized in that, The maximum detection distance of the reference material is calculated in the following way: Determine the current detection distance R between the passive nuclear level gauge and the reference material. 11 ; Detection of nuclear radiation data I released by the reference material 11 ; The maximum detection distance R1 of the reference material is calculated using the following formula: R1 = R 11 × Wherein, I1 represents the limiting radiation value corresponding to the passive nuclear level metering range.

13. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 1, characterized in that, 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.

14. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 13, characterized in that, 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: 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; 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: L = (1 / μ) × ln([q × V × A] / I) + D, where L is the measurement distance of the passive nuclear level gauge 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 is the limiting radiation value corresponding to the passive nuclear level gauge range, μ is the linear attenuation coefficient, A is the calibration coefficient used to correct the deviation between the theoretical model and the actual measurement system, and D is the correction constant used to compensate for the error; 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: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is the maximum detection distance of the reference material. The fitting function for calculating the maximum detection distance of the reference material is any of the following formulas: R1=b n ×V n +b n-1 ×V n-1 +…+b1×V+b0, where R1 is the maximum detection distance of the level gauge to the reference material, V is the quantity data of the reference material, and b0 to b… n b are the polynomial coefficients. n ≠0, n≥2; or, R1=c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, where R1 is the maximum detection distance for the reference material, H ref For reference material height data, c0 to c n c are the polynomial coefficients. n ≠0, n≥2.

15. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 13, characterized in that, The calculation and control module calculates the measurement range of the passive nuclear level gauge using a preset fitting function, including: 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; 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. Based on the experimental data, determine the coefficients in the fitting function; 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.

16. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 15, characterized in that, 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 +…+a1×q+a0, where L is the measurement range, q is the nuclear radiation characteristic data of the material to be measured, and a… n ≠0, n≥2; Based on the experiment, experimental data were obtained for multiple sets of correlated measurement ranges and nuclear radiation characteristic data; Data fitting is performed on the higher-order polynomial to determine the polynomial coefficients a0 to a0. n .

17. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 13, characterized in that, The calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using the following formula: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is the maximum detection distance of the reference material, which is obtained in the following way: 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: 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; 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. Based on the experimental data, determine the coefficients in the fitting function; 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.

18. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 17, characterized in that, 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: R1=b n ×V n +b n-1 ×V n-1 +…+b1×V+b0, where R1 is the maximum detection distance of the level gauge to the reference material, V is the quantity data of the reference material, and b… n ≠0, n≥2; Based on the experiment, multiple sets of associated maximum detection distance and quantity data of reference materials were obtained; Data fitting is performed on the higher-order polynomial to determine the polynomial coefficients b0 to b... n .

19. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 13, characterized in that, The calculation and control module calculates the measurement distance of the passive nuclear level gauge at a fixed position on the measured container to the reference material using the following formula: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is the maximum detection distance of the reference material, which is obtained in the following way: 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: 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; The material was measured and tested to obtain test data including the maximum detection distance and the height of the reference material; Based on the experimental data, determine the coefficients in the fitting function; 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; 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.

20. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 19, characterized in that, 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: R1 = c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, where R1 is the maximum detection distance for the reference material, H ref For reference material height data, c n ≠0, n≥2; Based on the experiment, multiple sets of related experimental data were obtained, including the maximum detection distance and height of the reference material. Data fitting is performed on the higher-order polynomial to determine the polynomial coefficients c0 to c1. n ; Define the installation height H of the passive nuclear level gauge relative to the fixed position of the container being measured. sum Based on H ref =H sum -R1, resulting in a new function used to calculate the maximum detection distance of the reference material: R1 = c n ×(H sum -R1) n +c n-1 ×(H sum -R1) n-1 +...+c1×(H) sum -R1)+c0.

21. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 13, characterized in that, The calculation and control module calculates the measurement distance of the passive nuclear level gauge to the reference material using the following formula: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is the maximum detection distance of the reference material, which is obtained in the following way: 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 R1 = c n ×H ref n +c n-1 ×H ref n-1 +…+c1×H ref +c0, where R1 is the maximum detection distance for the reference material, H ref For reference material height data, c n ≠0, n≥2; The material was measured and tested to obtain test data including the maximum detection distance and the height of the reference material; Based on the experimental data, determine the coefficients c0 to c in the fitting function. n ; 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.

22. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 13, characterized in that, 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: 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; 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; Based on the experimental data, determine the coefficients in the fitting function; 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.

23. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 22, characterized in that, The fitting function is the following polynomial: L = (1 / μ) × ln([q × V × A] / I) + D, where L is the measurement distance of the passive nuclear level gauge 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 is the limiting radiation value corresponding to the passive nuclear level gauge range, μ is the linear attenuation coefficient, A is the calibration coefficient used to correct the deviation between the theoretical model and the actual measurement system, and D is the correction constant used to compensate for the error; Based on the experiment, multiple sets of associated measurement distance L, reference material quantity data V, and nuclear radiation characteristic data q were obtained; Based on the experimental data, the linear attenuation coefficient μ, correction constant D, and calibration coefficient A in the fitting function are determined.

24. The passive nuclear level gauge measurement range or measurement distance determination system according to any one of claims 1-23, characterized in that, The passive nuclear level gauge used to measure the reference material is replaced by another type of nuclear radiation measuring device, which has the same nuclear radiation detection performance as the passive nuclear level gauge, or the nuclear radiation detection performance of the nuclear radiation measuring device is derived from the nuclear radiation detection performance of the passive nuclear level gauge.

25. The passive nuclear level gauge measurement range or measurement distance determination system according to any one of claims 1-23, characterized in that, The container used in the test is replaced by another container, which has the same structure as the container being measured, or the other container is a scaled-up or scaled-down version of the container being measured.

26. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 1, characterized in that, The system also includes the third-party device that executes the measurement steps triggered by the computing control module, 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. 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. 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.

27. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 26, characterized in that, 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.

28. The passive nuclear level gauge measurement range or measurement distance determination system according to any one of claims 1 to 23, or claim 26 or claim 27, is characterized in that, 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.

29. The passive nuclear level gauge measurement range or measurement distance determination system according to any one of claims 1 to 23, or claim 26 or claim 27, is characterized in that, The function of the calculation control module is implemented by the calculation processing unit of the material type identification and correction instrument, or by the calculation processing unit of the passive nuclear level gauge.

30. The passive nuclear level gauge measurement range or measurement distance determination system according to any one of claims 1 to 23, or claim 26 or claim 27, is characterized in that, It also 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; 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.

31. The passive nuclear level gauge measurement range or measurement distance determination system according to claim 30, characterized in that, The display device is integrated with one of the passive nuclear level gauge, material type identification and correction device, and calculation and control module, or the display device is connected to the passive nuclear level gauge, material type identification and correction device, and / or calculation and control module via wired or wireless connection.

32. The passive nuclear level gauge measurement range or measurement distance determination system according to any one of claims 1 to 23, or claim 26 or claim 27, is characterized in that, If the level value generated by the passive nuclear level gauge is less than or equal to a preset level threshold, or if the nuclear radiation data measured by the passive nuclear level gauge is less than or equal to a preset nuclear radiation threshold, the passive nuclear level gauge will output a prompt message in a preset format, the prompt message including the current measurement range information.

33. A method for determining the measuring range or measuring distance of a passive nuclear level gauge, characterized in that, The following steps are used to determine 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 relative to a reference material: The nuclear radiation characteristics data released by the material inside the measured container were detected using a material type identification and correction instrument. In response to a preset trigger condition, at least one of the following operations is performed: 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. Control 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; 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, is determined.

34. The method for determining the measurement range or measurement distance of a passive nuclear level gauge according to claim 33, characterized in that, 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, 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. 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; 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. 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 the formula to calculate the measurement distance of the passive nuclear level gauge to the reference material: R2 = R1 × Where R2 is the measurement distance of the level gauge to the reference material, P is the real-time relative material type value between the real-time reference material and the reference material, and R1 is the maximum detection distance of the reference material.

35. The method for determining the measurement range or measurement distance of a passive nuclear level gauge according to claim 34, characterized in that, The reference material is either material outside the range edge or material within the range; 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.

36. A passive nuclear level gauge method for measuring level, characterized in that, Includes the following steps: After determining the current measurement range of the passive nuclear level gauge using the measurement range or measurement distance determination system as described in any one of claims 1 to 32, 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: 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. 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.

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