Digital metering algorithm for volume of horizontal oil tank

Abstract

The invention provides a digital metering algorithm for the volume of a horizontal oil tank, and relates to the technical field of volume measurement of horizontal oil tanks. The digital measurement algorithm for the volume of the horizontal oil tank comprises the following measurement steps: step 1, data management, step 2, rotation axis calculation, step 3, data segmentation, step 4, shape fitting, step 5, tank body correction, step 6, volume calculation, step 7, model generation, and step 8, volume table generation. According to the method, the function of automatically generating the oil tank volume table through photoelectric geometric measurement data of horizontal oil tanks with different barrels and end sockets can be achieved, and a model capable of reversely resolving geometric dimension parameters of the horizontal tanks through a small number of data pairs meeting specific conditions and then generating the complete volume table is established; daily input, sale and storage data of a petrol station of a petrochemical sales system and data of a liquid level instrument system are directly used for horizontal metal tank calibration, and the precision error of the calibrated horizontal metal tank is lower than 0.2%.

Description

Technical Field

[0001] The present invention relates to the technical field of horizontal oil tank volume measurement, and specifically to a digital measurement algorithm for the volume of horizontal oil tanks. Background Art

[0002] At present, the capacity measurement of in-use horizontal metal tanks is divided into geometric measurement method and capacity comparison method. Although both methods can obtain the volume table, the shutdown operation of the calibration oil tank is required from the preparation stage. At the same time, the processes of both methods are relatively complex. The geometric measurement method requires tank cleaning operations, and the capacity comparison method has relatively strict requirements for calibration conditions. Therefore, both methods take a long time in the actual calibration process, resulting in a long shutdown time for gas stations. For this reason, we need to establish a model that can apply the existing petrochemical system data and calibrate horizontal metal tanks under operating conditions. Summary of the Invention

[0003] In view of the deficiencies of the prior art, the present invention provides a digital measurement algorithm for the volume of horizontal oil tanks, which can directly apply the daily incoming, outgoing, and inventory data of gas stations in the petrochemical sales system and the data of the liquid level gauge system to calibrate horizontal metal tanks, and the accuracy error of the calibrated horizontal metal tank is less than 2‰.

[0004] To achieve the above objectives, the present invention is realized through the following technical solutions: A digital measurement algorithm for the volume of horizontal oil tanks includes the following measurement steps:

[0005] Step 1: Data management, using the optical geometric measurement method to record survey data points, and dividing these survey data points into many smaller calculation units for independent storage;

[0006] Step 2: Rotation axis calculation, determining the rotation axis of the horizontal metal tank through Gaussian projection;

[0007] Step 3: Data segmentation, calculating the distance from the survey data points to the rotation axis, and judging the types of survey points. Preset a threshold ω, and fit the cylinder radius R to the closed interval [R - ω, R + ω];

[0008] Step 4: Shape fitting, shape fitting includes cylinder fitting and plug fitting. First is cylinder fitting, fitting the part of the horizontal metal tank cylinder through the previously marked survey data points of the cylinder tank body. Secondly is plug fitting, judging the type of the plug according to the spatial continuity of the survey data points of the plug, and fitting the determined type of plug with its corresponding surface equation, and finally finding the situation that can satisfy the vast majority of the survey points of the plug;

[0009] Step 5: Tank body correction. Based on the 3D point set of the surveying and mapping data points of the internal components, generate the geometric parameters of the internal components in the tank by combining the geometric characteristics of the stiffeners and metering pipes inside the tank, and correct the inclination angle of the tank body according to the direction vector of the tank body rotation axis;

[0010] Step 6: Volume calculation. Based on the above calculation data, use the data processing method of optical geometry measurement to calculate the volume of the horizontal metal tank at different liquid levels, and then generate a complete tank surface;

[0011] Step 7: Model generation. Based on the above calculation data, calculate the relationship between the geometric dimensions and the tank volume of the horizontal metal tank, establish a model that can reverse-solve the geometric dimension parameters of the horizontal tank through a few data pairs that meet specific conditions, and then generate a complete volume table;

[0012] Step 8: Volume table generation. Automatically calculate the characteristic geometric dimensions of horizontal oil tanks with different configurations according to the big data of incoming, outgoing, and inventory, and then generate the volume table of the horizontal oil tank, and automatically judge whether the generated volume table meets the requirement that the accuracy of the horizontal oil tank volume table is within 0.2%. If not, continue to calculate until it meets the requirement.

[0013] Preferably, the optical geometry measurement method in Step 1 is one of laser triangulation ranging, light speed ranging, or laser interferometry ranging. When using the laser triangulation ranging method, a large number of surveying and mapping data points will be generated, including a small number of invalid points caused by poor reflection characteristics of the tank wall. The process of data management needs to effectively record all surveying and mapping data points without excluding invalid points.

[0014] Preferably, in Step 1, the division principle of the surveying and mapping data points is to "block" them according to their spatial positions, that is, divide them into multiple small squares. The size of the divided space is determined by the recursive method, that is, the more dense the points are, the finer the division is. According to the size of the divided space, roughly judge whether the surveying points are inner surface surveying points or internal component surveying points.

[0015] Preferably, the specific calculation steps in Step 2 are as follows:

[0016] (1) Calculate the unit normal vector of the smallest division unit formed by each surveying and mapping data point, and translate all unit normal vectors to the same starting point to form an irregular spatial geometric body;

[0017] (2) Perform plane fitting on the geometric body, that is, project the geometric body onto a plane, and repeat this process until all projections can form a closed circle, and mark the fitting plane;

[0018] (3) Determine that the normal vector of the plane passing through the center of the fitting circle is the rotation axis of the horizontal metal tank, and the radius of the circle is the radius R of the cylindrical part of the horizontal metal tank.

[0019] Preferably, the specific steps of data segmentation in step three are as follows:

[0020] (1) If the distance from the data point to the rotation axis is less than (R - ω), it is determined as the mapping data point of the horizontal tank head (plug) / internal component. The distinction between the plug and the internal component is determined according to the size of the divided space in data management.

[0021] (2) If the distance from the data point to the rotation axis belongs to [R - ω, R + ω], this point is determined as the mapping data point of the cylindrical tank body.

[0022] (3) If the distance from the data point to the rotation axis is greater than (R - ω), it is determined as an invalid point.

[0023] Preferably, the data pair in step seven consists of the liquid level difference of the horizontal metal tank and the corresponding volume. The liquid level difference comes from the liquid level gauge system in the tank, and the corresponding volume is the incoming goods data or sales data. At the same time, to effectively avoid the influence of accidental errors of the instrument on the reverse calculation, the number of data pairs is not less than 10.

[0024] The present invention provides a digital metering algorithm for the volume of a horizontal oil tank, which has the following beneficial effects:

[0025] 1. The present invention can realize the function of automatically generating the oil tank volume table from the optoelectronic geometric measurement data of horizontal oil tanks with different cylinders and heads, and directly apply the daily incoming, outgoing, and inventory data of the gas stations in the petrochemical sales system plus the data of the liquid level gauge system to calibrate the horizontal metal tank. The accuracy error of the calibrated horizontal metal tank is less than 2‰.

[0026] 2. The present invention establishes a model that can reverse calculate the geometric dimension parameters of the horizontal tank through a few data pairs that meet specific conditions, and then generate a complete volume table. And according to the big data of incoming, outgoing, and inventory, it automatically calculates the characteristic geometric dimensions of horizontal oil tanks with different configurations, and then generates the volume table of the horizontal oil tank, and automatically judges whether the generated volume table meets the accuracy requirements of the horizontal oil tank volume table, effectively eliminating the errors caused by temperature changes during the calibration process, and establishing the qualified discrimination conditions and the operation process of unqualified results in the actual operation process. Specific embodiments

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0028] Embodiment:

[0029] An embodiment of the present invention provides a digital measurement algorithm for the volume of a horizontal oil tank, including the following measurement steps:

[0030] Step 1: Data management. The optical geometric measurement method is used to record survey data points, and these survey data points are divided into many smaller calculation units for independent storage;

[0031] Step 2: Rotation axis calculation. The rotation axis of the horizontal metal tank is determined by Gaussian projection;

[0032] Step 3: Data segmentation. Calculate the distance from the survey data points to the rotation axis, and determine the type of the survey points. A preset threshold ω is set, and the fitted cylinder radius R is in the closed interval [R - ω, R + ω];

[0033] Step 4: Shape fitting. Shape fitting includes cylinder fitting and plug fitting. First is cylinder fitting. The part of the horizontal metal tank cylinder is fitted through the previously marked survey data points of the cylinder tank body. Second is plug fitting. According to the spatial continuity of the survey data points of the plug, the type of the plug is judged, and the corresponding surface equation is used to fit the determined type of plug, and finally the situation that can satisfy the vast majority of the plug survey points is found;

[0034] Step 5: Tank body correction. According to the three-dimensional point set of the survey data points of the internal components, the geometric parameters of the internal components in the tank are generated in combination with the geometric characteristics of the internal stiffeners and metering pipes in the tank, and the inclination angle of the tank body is corrected according to the direction vector of the rotation axis of the tank body;

[0035] Step 6: Volume calculation. According to the above calculation data, the volume of the horizontal metal tank at different liquid levels is calculated by using the data processing method of optical geometry, and then a complete tank table is generated;

[0036] Step 7: Model generation. According to the above calculation data, the relationship between the geometric dimensions of the horizontal metal tank and the tank volume is calculated, and a model that can inversely solve the geometric dimension parameters of the horizontal tank through a few data pairs that meet specific conditions and then generate a complete volume table is established;

[0037] Step 8: Volume table generation. Automatically calculate the characteristic geometric dimensions of horizontal oil tanks with different configurations according to the big data of incoming, outgoing, and inventory, and then generate the volume table of the horizontal oil tank, and automatically judge whether the generated volume table meets the requirement that the accuracy of the volume table of the horizontal oil tank is within 0.2%. If not, continue to calculate until it meets.

[0038] Specifically, through Steps 1 to 6, the research and development of the algorithm for the main configuration of the horizontal oil tank is completed, which can realize the function of automatically generating the oil tank volume table from the optoelectronic geometric measurement data of the horizontal oil tank with different cylinders and heads, and complete the verification of the automatically generated volume table of the horizontal oil tank.

[0039] In this embodiment, the optical geometric measurement method in step one is one of laser triangulation ranging, light speed method ranging or laser interferometry ranging. When using laser triangulation ranging, a large number of surveying and mapping data points will be generated, including a small number of invalid points due to the poor reflective characteristics of the tank wall. The process of data management needs to effectively record all surveying and mapping data points without excluding invalid points.

[0040] Furthermore, in step one, the division principle of the surveying and mapping data points is to "block" them according to their spatial positions, that is, divide them into multiple small squares. The size of the divided space is determined by the recursive method, that is, the denser the points, the finer the division. According to the size of the divided space, roughly judge the type of the surveying and mapping points as inner surface surveying and mapping points or internal component surveying and mapping points.

[0041] Furthermore, the specific steps of the calculation in step two are as follows:

[0042] (1) Calculate the unit normal vector of the smallest division unit formed by each surveying and mapping data point, and translate all unit normal vectors to the same starting point to form an irregular spatial geometric body;

[0043] (2) Perform plane fitting on the geometric body, that is, project the geometric body onto a plane, and repeat this process until all projections can form a closed circle, and mark the fitting plane;

[0044] (3) Determine that the normal vector of the plane passing through the center of the fitting circle is the rotation axis of the horizontal metal tank, and the radius of the circle is the radius R of the cylindrical part of the horizontal metal tank.

[0045] Furthermore, the specific steps of data segmentation in step three are as follows:

[0046] (1) If the distance from the data point to the rotation axis is less than (R - ω), it is determined as the surveying and mapping data point of the horizontal tank head (plug) / internal component. The distinction between the plug and the internal component is determined according to the size of the divided space in data management;

[0047] (2) If the distance from the data point to the rotation axis belongs to [R - ω, R + ω], this point is determined as the surveying and mapping data point of the cylindrical tank body;

[0048] (3) If the distance from the data point to the rotation axis is greater than (R - ω), it is determined as an invalid point.

[0049] Furthermore, the data pair in step seven consists of the liquid level difference of the horizontal metal tank and the corresponding volume. The liquid level difference comes from the liquid level gauge system in the tank, and the corresponding volume is the incoming goods data or the sales data. At the same time, to effectively avoid the influence of the accidental error of the instrument on the inverse calculation, the number of data pairs is not less than 10.

[0050] Specifically, the volume value corresponding to each data pair is not less than 5000L, because the accuracy of the liquid level gauge is 0.5mm, with 30m 3Take the tank as an example: In the middle part of the tank body, the volume corresponding to a liquid level of 1 mm is 20 L, and that corresponding to 0.5 mm is 10 L. 10 L accounts for 2‰ of 5000 L. To ensure that the error impact of the liquid level gauge is less than the requirement of the volume calibration accuracy, it is specifically stipulated that the volume value (volume) of each piece of collected data shall be no less than 5000 L.

[0051] The volume impacts of different geometric dimensions on different parts of the horizontal tank are different. We stipulate that the data pairs collected shall meet the following distribution conditions. First, the data pairs with the liquid level difference belonging to the range from 350 mm to 30% of the total height of the horizontal metal tank account for 30% of the total amount. Second, the data pairs with the liquid level difference belonging to the range from 30% to 60% of the total height of the horizontal metal tank account for 40% of the total amount. Third, the data pairs with the liquid level difference belonging to the range from 60% to 90% of the total height of the horizontal metal tank account for 30% of the total amount. The height of the horizontal metal tank can be obtained from the original tank volume table.

[0052] It should be particularly noted that the data pairs composed of the liquid level difference and the corresponding volume of the horizontal metal tank are constant-temperature data pairs, that is, there is no volume change caused by temperature change throughout the process.

[0053] When judging the influence of the geometric dimensions of the horizontal metal tank on the volume, for a horizontal metal tank without obvious concavity and convexity phenomena and permanent deformation affecting the capacity at the plug and the cylinder of the horizontal tank, the corresponding relationship between its capacity and the liquid level height is mainly determined by the geometric dimensions of the horizontal metal tank.

[0054] Among them, the most important geometric parameters include the vertical diameter, horizontal diameter, total cylinder length, plug type, and inclination angle. Take a horizontal tank with a capacity of 30 m 3 as an example. For a horizontal metal tank with a vertical diameter of 2600 mm, a horizontal diameter of 2600 mm, a total cylinder length of 5270 mm, a front and rear plug length of 416 mm, and an inclination angle of 0°, the total capacity is 30284 L; when the total cylinder length increases by 1 mm, its overall capacity increases by 5 L, the middle part capacity increases by 3 L, the bottom capacity increases by 0 L, and the top capacity increases by 5 L; when the vertical diameter decreases by 1 mm, its overall capacity decreases by 12 L, the middle part capacity decreases by 2 L, the bottom capacity decreases by 0 L, and the top capacity decreases by 12 L.

[0055] When automatically collecting data and calculating the characteristic geometric dimensions of the horizontal tank, a model for reverse-solving the geometric dimensions of the horizontal metal tank with multiple data pairs under constant-temperature conditions is established. However, the data pairs collected under actual working conditions are those with real-time temperature changes, thus affecting the accuracy of the reverse solution.

[0056] Collect the daily profit and loss data collection information of 95# gasoline at Beichen Chenping Gas Station on different dates, and the following Table 1 is obtained.

[0057]

[0058] (Table 1 is the daily profit and loss data collection table)

[0059] Taking the first piece of data in Table 1 (the first data pair) as an example: the volume of the horizontal tank with a liquid level height of 2148.5 mm is 27558.95 L, and the temperature is 16.2 °C. After a certain amount of oil is dispensed, the liquid level height becomes 1250.8 mm, the volume becomes 15032.40 L, and the temperature becomes 15.9 °C. However, the volume of the dispensed oil is not 12526.55 L (27558.95 L minus 15032.4 L). Taking the liquid level heights ① 2148.5 mm, ② 1250.8 mm and the actual dispensed volume V20 of the oil dispenser to form data pairs for reverse calculation. The calculation process is as follows: Enumerate horizontal metal tanks with different geometric dimensions, and record the volumes corresponding to the two heights ① 2148.5 mm and ② 1250.8 mm respectively. Convert the volume of the oil at the actual temperature to the volume of the oil at the standard temperature (20 °C) through the oil volume expansion coefficient. The volume difference between the two standard temperatures is the standard volume of the oil dispensed from the tank. At the same time, apply the dispensed oil volume recorded by the fuel card query system, and convert the dispensed oil volume at the actual temperature to the volume of the oil at the standard temperature (20 °C), which is the actual dispensed volume V20 of the oil dispenser in the first piece of data in the above table: 12635.31 L. When the difference between the two standard temperature volumes is less than 2‰ (the profit and loss rate is less than 2‰), it is determined to be qualified, and the profit and loss rates of all data pairs are less than 2‰.

[0060] Collect the daily profit and loss data verification information of 95# gasoline at Beichen Chenping Gas Station on different dates to obtain Table 2 below.

[0061]

[0062] (Table 2 is the daily profit and loss data verification table)

[0063] As shown in Table 2, record the geometric dimensions of the horizontal metal tank, complete the reverse calculation. The principle of calculating the characteristic geometric dimensions of the horizontal tank using the incoming goods data is similar, only replacing the actual dispensed volume V20 of the oil dispenser with the actual delivered quantity V20 of the oil.

[0064] If the standard volume difference (profit and loss rate) of all data pairs in the final result determination is less than 2‰, it is considered that the calibration process of the horizontal metal tank is completed, and the geometric dimensions of the horizontal metal tank can be recorded and a tank table can be generated. However, due to the existence of accidental errors in the system, there may be a very small number of data pairs with a profit and loss rate greater than 2‰. Therefore, we stipulate that during use, if the number of finally unqualified collected data (the profit and loss rate after reverse calculation is greater than 2‰) exceeds 20% of the total number of collected data, all data need to be collected again and calculated again. If the number of unqualified data is less than 20% of the total number of collected data, the unqualified data need to be collected again and recalculated until all are qualified. Taking 10 collected data as an example, if two data are unqualified, these two data need to be excluded, and two new data need to be collected. Then, together with the 8 data left after the previous calculation, they form a new 10-data group and are recalculated until all are qualified and the tank table is output.

[0065] To effectively ensure the correctness of this method, 500 horizontal metal tanks that have been calibrated by optical geometric measurement and completed acceptance and delivery are verified in reverse. That is, instead of directly using the data of all survey points calibrated by optical geometric measurement, only the geometric dimension data of the tank body is brought in, and the capacity of the horizontal metal tank is calculated by the geometric method. It is found that the difference between the volume table calibrated by optical geometric measurement and the volume table of the tank body calculated from the geometric dimensions of the tank body is 8L, which can be ignored.

[0066] When reverse-solving the geometric dimensions of a horizontal metal tank, the solution idea is to utilize the influence of geometric dimensions on the volume, enumerate a large number of horizontal metal tanks with different geometric dimensions, compare them one by one, and find and record the geometric dimensions of the horizontal metal tank that meet the preset data pairs. Taking two horizontal tanks A and B with a capacity of 30m 3 as an example, the geometric parameters of horizontal tank A are: vertical diameter 2600mm, horizontal diameter 2600mm, total cylinder length 5270mm, front and rear plug lengths 416mm, and tilt angle 0°. The geometric parameters of horizontal tank B are: vertical diameter 2580mm, horizontal diameter 2600mm, total cylinder length 5270mm, front and rear plug lengths 416mm, and tilt angle 0°. Their overall capacities are different, but the volumes corresponding to a liquid level height of 1300mm are both 15144L. However, as the number of preset data pairs increases, the geometric dimensions of the horizontal tanks that meet all data pairs tend to be stable. Randomly select 15 data pairs for horizontal metal tanks with known tank capacities, and sequentially solve the geometric dimensions of the horizontal metal tanks that meet 1 randomly selected data pair, 2 randomly selected data pairs, and up to all 15 data pairs. We find that when the number of randomly selected data pairs reaches 6, the error between the geometric dimensions of the horizontally reverse-solved metal tank and the actual geometric dimensions of the metal tank is only 0.6mm. It can be determined that the geometric dimensions of the horizontally reverse-solved metal tank with 6 data pairs can effectively replace the actual geometric dimensions of the horizontal tank.

[0067] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A digital measurement algorithm for the volume of a horizontal oil tank, characterized in that, It includes the following measurement steps: Step 1: Data management. Optical geometric measurement method is used to record surveying and mapping data points, and these surveying and mapping data points are divided into many smaller calculation units for independent storage; Step 2: Rotation axis calculation. The rotation axis of the horizontal metal tank is determined by Gaussian projection; Step 3: Data segmentation. Calculate the distance from the surveying and mapping data points to the rotation axis, and judge the types of surveying points. Preset the threshold ω, and fit the cylinder radius RR as the closed interval [R - ω, R + ω]; Step 4: Shape fitting. Shape fitting includes cylinder fitting and end fitting. First is cylinder fitting. The part of the horizontal metal tank cylinder is fitted through the previously marked surveying and mapping data points of the cylinder body. Second is end fitting. Judge the type of the end according to the spatial continuity of the end surveying and mapping data points, and use the corresponding surface equation to fit the determined type of end, and finally find the situation that can satisfy the majority of the end surveying and mapping points; Step 5: Tank body correction. According to the three-dimensional point set of the internal component surveying and mapping data points, combine the geometric characteristics of the internal stiffeners and metering pipes in the tank to generate the geometric parameters of the internal components in the tank, and correct the inclination angle of the tank body according to the direction vector of the tank body rotation axis; Step 6: Volume calculation. According to the above calculation data, use the data processing method of optical geometry measurement to calculate the volume of the horizontal metal tank at different liquid levels, and then generate a complete tank surface; Step 7: Model generation. According to the above calculation data, calculate the relationship between the geometric dimensions of the horizontal metal tank and the tank volume, establish a model that can reverse calculate the geometric dimension parameters of the horizontal tank through a few data pairs that meet specific conditions, and then generate a complete volume table model; Step 8: Volume table generation. Automatically calculate the characteristic geometric dimensions of horizontal oil tanks with different configurations according to the big data of incoming, outgoing and inventory, and then generate the volume table of the horizontal oil tank, and automatically judge whether the generated volume table meets the requirement that the accuracy of the horizontal oil tank volume table is within 0.2%. If not, continue to calculate until it meets the requirement.

2. The digital metering algorithm for the volume of a horizontal oil tank according to claim 1, characterized in that, The optical geometric measurement method in Step 1 is one of laser triangulation ranging, light speed ranging or laser interferometry ranging. When using the laser triangulation ranging method, a large number of surveying and mapping data points will be generated, including a small amount of invalid points due to the poor reflection characteristics of the tank wall. The process of data management needs to effectively record all surveying and mapping data points without excluding invalid points.

3. A digital metering algorithm for the volume of a horizontal oil tank according to claim 1, characterized in that, In Step 1, the division principle of the surveying and mapping data points is to "block" according to their spatial positions, that is, divided into multiple small squares. The division space size is determined by the recursive method, that is, the more dense the points are, the finer the division is. According to the size of the division space, roughly judge the types of surveying points as inner surface surveying points or internal component surveying points.

4. The digital metering algorithm for the volume of a horizontal oil tank according to claim 1, characterized in that, The specific calculation steps in Step 2 are as follows: (1) Calculate the unit normal vector of the smallest division unit formed by each surveying and mapping data point, and translate all unit normal vectors to the same starting point to form an irregular spatial geometric body; (2) Perform plane fitting on the geometric body, that is, project the geometric body onto a plane, and repeat this process until all projections can form a closed circle, and mark the fitting plane; (3) Determine that the normal vector of the overfitting center plane is the rotation axis of the horizontal metal tank, and the circular radius is the radius R of the cylindrical part of the horizontal metal tank.

5. A digital metering algorithm for the volume of a horizontal oil tank according to claim 1, characterized in that, The specific steps of data segmentation in step (3) are as follows: (1) If the distance from the data point to the rotation axis is less than (R - ω), it is determined as the surveying and mapping data point of the horizontal tank head (plug) / internal component, and the distinction between the plug and the internal component is determined according to the size of the divided space in data management; (2) If the distance from the data point to the rotation axis belongs to [R - ω, R + ω], this point is determined as the surveying and mapping data point of the cylindrical tank body; (3) If the distance from the data point to the rotation axis is greater than (R - ω), it is determined as an invalid point.

6. The digital metering algorithm for the volume of a horizontal oil tank according to claim 1, characterized in that, The data pair in step (7) consists of the liquid level difference of the horizontal metal tank and the corresponding volume. The liquid level difference comes from the liquid level gauge system in the tank, and the corresponding volume is the incoming goods data or sales data. At the same time, to effectively avoid the influence of accidental errors of the instrument on the inverse calculation, the number of data pairs is not less than 10.

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