JP4039579B2 - Liquid volume management system - Google Patents

Description

  The present invention relates to a liquid amount management system for a liquid storage tank when metered and sold from a liquid storage tank through a measuring machine in a liquid supply station, a kerosene shop, or the like.

  Liquid storage tanks buried underground often have an approximate cylindrical shape in terms of strength and the like. Therefore, when calculating the amount of liquid in the liquid storage tank, a method of calculating the amount of liquid using the function and table data that define the relationship between the liquid level and the liquid amount from the liquid level data by the liquid level detector Has been adopted.

  However, an error occurs in the relationship between the liquid level and the liquid amount depending on manufacturing tolerances and installation conditions of the liquid storage tank. Therefore, for example, as seen in Patent Document 1, calibration data is obtained from the liquid amount metered and discharged by the weighing machine and the liquid level data of the liquid level detector, and the relationship between the liquid level and the liquid amount is obtained. Processing to correct is performed.

  That is, the actual liquid volume data measured by the weighing machine and the liquid level change data measured by the liquid level detector are compared, and the calibration data that defines the relationship between them is calculated and calibrated. These efforts are continued until there is no meaningful change in the data.

  However, in the above-described conventional method, the liquid amount and liquid level data calculated by volume integration from a certain liquid level are used as calibration data, and the data integration period is long. In addition, there is a problem that an error occurs in calibration data due to fluctuations in the liquid amount and the liquid level accompanying environmental changes such as temperature changes. Furthermore, in the conventional method, each data is automatically processed as needed due to changes in the liquid level data of the liquid level detector and the liquid level data of the weighing machine. It is difficult to confirm and manage whether or not. Therefore, the calibration process is performed by inadvertent data due to the vibration of the liquid level, and as a result, the calibration process may not be performed properly. Also, it is very difficult to confirm and verify whether or not the calibration process has been performed appropriately.

  Based on these problems, the applicant of the present application previously disclosed a new liquid amount management system in Patent Document 2. This liquid volume management system can minimize the effects of environmental changes such as temperature changes by adopting liquid volume gradient data that can be collected in a short time in the calibration process. The total time required for the system can be shortened.

  However, when using a liquid volume gradient, the actual liquid volume can be calculated by setting the liquid volume at one liquid level and using the liquid volume gradient data as a reference. The amount needs to be calculated. Conventionally, the liquid volume at one liquid level was assumed to be the correct liquid volume, and the liquid volume at the other liquid level was calculated. However, if the reference liquid volume is not correct, There was also an error in the amount of liquid in the level, and as a result, there was a problem that the calibration process could not be performed properly.

In addition, when calculating the liquid level gradient, data on the amount of liquid supplied by the weighing machine (measurement data) is used, but in reality there is a difference between each weighing machine, and the weighing data from the weighing machine If this is used as it is, an error is caused by the instrumental error. In particular, when the amount of supplied liquid is small, the error due to the instrumental error cannot be ignored, and there is a problem that the calibration process is hindered.
JP-A-1-163621 JP 2005-156262 A

  The present invention relates to the improvement of the liquid amount management system of Patent Document 2 described above, and its object is to provide a liquid amount management system capable of performing a more accurate calibration process.

  Another problem is to improve the accuracy when calculating the liquid volume from the liquid volume gradient.

  Still another problem is to be able to accurately determine the amount of liquid supplied from the weighing machine when calculating the liquid amount gradient.

  The present invention obtains a liquid level corresponding to half of the total capacity of the liquid storage tank when calculating the liquid volume from the liquid volume gradient, and the liquid level at this liquid level is defined as half the total capacity of the liquid storage tank. The liquid volume after calibration at each liquid surface level is calculated based on the liquid volume gradient with this set as a reference.

  Specifically, when the vertical cross-sectional shape of the liquid storage tank is substantially circular, the liquid amount gradient at the first liquid surface level below the diameter line of the liquid storage tank is extracted from the liquid amount gradient storage means, and the liquid A second liquid level having the same liquid level gradient as the extracted liquid level gradient is extracted from the liquid level gradient storage means above the diameter line of the storage tank, and the first liquid level and the second liquid level are extracted. A third liquid level that is the midpoint of the level is calculated, and this operation is repeated a plurality of times at different liquid levels to calculate an average value of the third liquid level, and the average of the third liquid levels The liquid volume at the liquid level of the value can be set to half of the total capacity of the liquid storage tank.

  Further, according to the present invention, when the liquid amount gradient (ΔQ / ΔH) is calculated, the data obtained by correcting the weighing data by the instrumental difference data of the measuring machine is used as the liquid supply amount (ΔQ) supplied by the measuring machine. It is intended to be used.

  That is, the present invention provides a liquid-feeding meter connected to a liquid storage tank, a liquid level detector for detecting a liquid level of the liquid storage tank, a liquid level and a liquid amount of the liquid storage tank, In a liquid level management system comprising: a liquid level display device that calculates and displays a liquid level from a liquid level detected by the liquid level detector based on a conversion table that defines the relationship of , The weighing data is corrected by the instrument difference data of the weighing machine to obtain the liquid supply amount (ΔQ) supplied by the measuring machine. Liquid level gradient storage means for calculating a liquid volume gradient (ΔQ / ΔH) from the liquid level change (ΔH) and storing the liquid volume gradient in association with one liquid level in the liquid level change. And half of the total capacity of the liquid storage tank A corresponding liquid level is obtained, and the liquid amount at the liquid level is set as half of the total capacity of the liquid storage tank. Based on this, each liquid level is stored based on the liquid level gradient stored in the liquid level gradient storage means. A liquid level after calibration at the liquid level is calculated, a calibration conversion table for defining the relationship between the liquid level in the liquid storage tank and the liquid level after calibration is created, and the liquid level is calculated based on the calibration conversion table. The liquid amount is calculated from the level and displayed.

  The present invention employs liquid volume gradient data that can be collected in a short time in the calibration process, so that the influence of environmental changes such as temperature changes can be minimized, and data necessary for calibration Can be collected in a short period of time, so the total time required for the calibration process can be shortened.

  And when calculating a liquid quantity from a liquid quantity gradient, the precision of a liquid quantity calculation can be improved by calculating | requiring the liquid level corresponding to half of the total capacity of a liquid storage tank appropriately.

  Furthermore, by correcting the weighing data of the weighing machine with the instrumental difference data, the amount of liquid supplied by the weighing machine can be accurately obtained, and the accuracy of the calibration process can be improved.

  Embodiments of the present invention will be described below based on examples shown in the drawings.

  FIG. 1 is a system configuration diagram of a liquid amount management system according to the present invention. In the figure, a liquid storage tank 1 embedded in the basement is provided with a liquid level detector 2 and a measuring machine 3 is connected via a pipe, and a liquid supply nozzle provided in the measuring machine 3. According to 4, liquid supply is performed. In the present embodiment, a magnetostrictive liquid level detector or a liquid level detector having an accuracy equivalent to the magnetostrictive liquid level detector 2 is used as the liquid level detector 2, and the height of the liquid storage tank 1 is set at a resolution of 0.05 mm or less. The liquid level is detected.

  Each liquid level detector 2 is connected to the data collecting means 6 and the liquid level display device 7 with a cable, and the liquid level display unit 7 converts the liquid level to a liquid level and displays the liquid level. ing. The liquid amount display device 7 is connected to a communication line of the same series as the POS 8 that is a host system that communicates with the weighing machine 3, and starts the liquid supply and liquid supply performed between the weighing machine 3 and the POS 8. Communication data such as the end and the amount of liquid supply can be acquired. That is, when the liquid supply nozzle 4 is removed from the measuring device 3, a liquid supply start signal is sent to the POS 8 by the ON signal from the nozzle switch 5. Further, when the liquid supply nozzle 4 is returned to the measuring device 3, the liquid supply end signal and the liquid supply amount data are sent to the POS 8 by the OFF signal from the nozzle switch 5. The liquid amount display device 7 can acquire these signals and data.

  FIG. 2 is a block diagram showing the configuration of the data collection means 6 and the liquid amount display device 7.

  The data collecting means 6 includes a liquid level detector switching means 6a, from which liquid storage tank 1 of the liquid storage tanks 1 among the liquid storage tanks 1 the liquid level detector switching means 6a collects. Can be selected. Further, the data collecting means 6 includes data averaging / noise removing means 6b for performing averaging / noise removal processing on the liquid level data obtained from the liquid level detector 2. Further, the liquid level detector 2 has a built-in temperature sensor, which can detect the average temperature of the liquid, and this data can be read out by a CPU 7a of the liquid amount display device 7 described later.

  The liquid amount display device 7 receives the liquid level data from the data collecting means 6 and performs various calculations, a conversion table for defining the relationship between the liquid level and the liquid amount, and in this embodiment, the diameter of the tank. On the other hand, a conversion table storage unit 7b that stores a conversion table divided into about 1000, a liquid amount gradient storage unit 7c that stores liquid amount gradient data collected in the conversion table calibration process described later, and a post-calibration process Calibration conversion table storage means 7d for storing the calibration conversion table of the above, input means 7i for inputting the instrumental difference data for each weighing machine 5, and instrumental difference data storage means for storing the instrumental difference data input by the input means 7i 7j.

  The CPU 7a of the liquid amount display device 7 uses the conversion table stored in the conversion table storage unit 7b or the calibration conversion table stored in the calibration conversion table storage unit 7d to receive the liquid received from the liquid level detector 2. An operation for converting the surface level data into a liquid amount is performed, and the calculation result is transmitted to the liquid amount display means 7e to display the liquid amount. Further, the CPU 7a can calculate the liquid supply amount by correcting the weighing data of the weighing machine 3 using the difference data for each weighing instrument 5 stored in the instrument difference data storage means 7j. Further, the CPU 7a is connected with a printing means 7f, a communication port 7g, and an SS-LAN communication port 7h. The liquid amount obtained by the arithmetic processing of the CPU 7a, the measurement data of the measuring machine 5, and the corrected liquid supply amount In addition, various data stored in the conversion table storage unit 7b, the liquid amount gradient storage unit 7c, the calibration conversion table storage unit 7d, and the instrumental difference data storage unit 7j are printed or confirmed by connecting a personal computer or the like. Be able to.

  Hereinafter, the procedure of the calibration process of the conversion table in the liquid amount management system of the present invention will be described. The calibration processing of the present invention includes a data acquisition step for calibration processing, a data processing step for obtaining data for calibrating the conversion table from the acquired data, and a calibration conversion table creation step for creating a calibration conversion table from the obtained data These are roughly divided into three processes.

  FIG. 3 is a flowchart showing the data acquisition process. 1 to 3, first, when the liquid supply nozzle 4 is removed from the weighing machine 3, the CPU 7 a detects the liquid level level data before liquid supply from the liquid level detector 2 by the ON signal from the nozzle switch 5. To get. Then, when the liquid supply nozzle 4 is returned to the measuring device 3, the CPU 7a obtains the liquid level data after liquid supply and the liquid average temperature in the tank from the liquid level detector 2 by the OFF signal from the nozzle switch 5. Next, the weighing data is acquired from the weighing machine 3. Then, the instrumental difference data of the weighing machine 3 is acquired from the instrumental difference data storage means 7j, the measurement data is corrected by the instrumental difference data, and the corrected measurement data is adopted as the liquid supply amount data. That is, the liquid supply amount data ΔQ is obtained by a calculation formula of ΔQ = measurement data × (1 + instrument difference (%) × 100).

  FIG. 4 is a flowchart showing a data processing process. In this process, first, it is determined whether or not the data (liquid level data and liquid supply amount data) acquired in the data income process is appropriate as calibration data. In other words, in order for the liquid level change before and after the liquid supply to be detected by the liquid level detector, it is necessary to exceed at least one liquid level level detected by the liquid level detector. In order to improve detection accuracy, it is preferable to exceed a plurality (about 2 to 3) of liquid level intervals. In this embodiment, it is determined whether or not the change in the liquid level before and after the liquid supply exceeds two liquid level levels.

  When the change in the liquid level before and after the liquid supply does not exceed the interval between the two liquid levels, the data is temporarily stored, the next data addition instruction is given, and the data acquisition is performed. The next data is added until the change in the liquid level exceeds the interval between the two liquid levels.

  When the liquid level change exceeds two liquid level intervals by one or a plurality of times of liquid supply, it is determined whether or not the temperature change during the data acquisition period is within a predetermined range. In this embodiment, it is determined whether or not the average temperature change of the liquid in the tank is within ± 0.02 ° C. If the above-described temperature change exceeds ± 0.02 ° C., errors due to fluctuations in the liquid level due to the temperature change cannot be ignored, and the acquired data is discarded.

When the temperature change is within ± 0.02 ° C., the data is validated, and the liquid level gradient G (ΔQ / ΔH) is calculated from the liquid level change (ΔH) and the liquid supply amount (ΔQ) as shown in FIG. Calculated by reference). When the liquid level change (ΔH) is ΔH = H _m2 −H _m1 , the liquid level gradient is linked to the liquid level closest to (H _m2 −H _m1 ) / 2, A liquid gradient is assumed. The liquid level gradient data associated with the liquid level is stored in the liquid level gradient storage means 7c (see FIG. 2) in the format shown in FIG. 5, and the liquid level gradient data is predetermined at each liquid level. After obtaining the number of times, the average value is calculated.

    The liquid level gradient storage means 7c manages the liquid level by dividing it into a plurality of blocks. When all of the liquid level gradient data is obtained for one block, conversion is performed based on the obtained liquid level gradient data. The conversion table stored in the table storage means 7b (see FIG. 2) is calibrated to create a calibration conversion table.

As shown in FIG. 6, the liquid amount corresponding to each liquid level is input to the conversion table of the conversion table storage unit 7b. Further, the liquid level gradient G (ΔQ / ΔH) at each liquid level is calculated and input from the liquid level and liquid volume data. The liquid level gradient G at each liquid level is calculated from data on the liquid level and liquid level immediately above and below the corresponding liquid level. For example, the liquid amount gradient G _{n at} the liquid level H _n is calculated by the equation: G _n = (Q _{n + 1} −Q _n−1 ) / (H _{n + 1} −H _n−1 ).

  FIG. 7 is a flowchart showing the calibration conversion table creation step, and FIG. 8 is a diagram showing the calibration conversion table.

  The calibration data table is formed in the same manner as the conversion data table shown in FIG. 6, and the liquid volume, liquid volume gradient, and calibration liquid volume gradient data corresponding to each liquid level are input. In the conversion table and the calibration conversion table, the liquid level is divided into a plurality of blocks and managed in the same manner as the liquid amount gradient data table described above with reference to FIG.

  In the calibration conversion table creation step, first, the calibration conversion table is initialized, and each data of the conversion table is automatically entered by the CPU 7a (see FIG. 2) in each column of the liquid level, liquid amount, and liquid amount gradient of the calibration conversion table. Copy to.

  Next, in the liquid volume gradient data table described with reference to FIG. 5, the liquid volume gradient data of the block in which all the liquid volume gradient data are prepared is stored in the calibration liquid volume gradient column of the calibration conversion table in units of blocks. It is automatically copied by the CPU 7a. Thereafter, the CPU 7a checks the continuity of the calibration fluid amount gradient data. Specifically, it is checked whether there is noise (abnormal value) by referring to all calibration fluid volume gradient data in the block. If there is an abnormal value, the abnormal value is calibrated. By substituting the previous liquid volume gradient data, the abnormal value is removed and the calibration liquid volume gradient data is corrected. Further, the tendency of the numerical value increase / decrease between the data is judged, and the calibration fluid amount gradient data is corrected.

  When the data continuity check is completed, the CPU 7a checks the validity of the data in units of blocks. Specifically, the data of the liquid volume gradient before calibration and the calibration liquid volume gradient are compared, and if the difference is within a predetermined range (within ± 3% in the example), the data in that block is valid. Then, calibration is performed by substituting the data of the liquid volume gradient in the calibration conversion table with the data of the calibration liquid volume gradient. When the difference between the liquid volume gradient before calibration and the calibration liquid volume gradient exceeds a predetermined range, the calibration is not performed and the process returns to the data acquisition process shown in FIG. 3 again.

  When the calibration of the liquid volume gradient data is completed in the block, the liquid volume data is calibrated based on the liquid volume gradient data after calibration and reflected in the liquid volume display. Specifically, a liquid level corresponding to half of the total capacity of the liquid storage tank 1 is obtained, and the liquid amount at this liquid level is set as half of the total capacity of the liquid storage tank 1, and the liquid volume is determined based on this. Based on the liquid volume gradient stored in the gradient storage means 7c, the liquid volume after calibration at each liquid level is calculated and calibrated.

  Hereinafter, a procedure for obtaining a liquid level corresponding to half of the total capacity in a liquid storage tank having a substantially circular longitudinal section will be described. In other words, this means that the center-of-gravity position in the height direction of the substantially circular shape is obtained.

  FIG. 9 shows the relationship between the liquid level and the liquid amount gradient in a liquid storage tank having a substantially circular longitudinal section. As shown in the figure, in a liquid storage tank having a substantially circular longitudinal cross-sectional shape, the liquid amount gradient becomes maximum at the center in the height direction of the tank (Hn / 2), that is, near the diameter line D, and below the diameter line D. And the upper part is almost symmetrical.

In the present invention, the CPU 7a first extracts the liquid amount gradient at the first liquid level H _X1 below the diameter line D from the liquid amount gradient storage means 7c (see FIG. 5). Next, above the diameter line D, the second liquid level H _Y1 having the same liquid level gradient as the first liquid level H _X1 is extracted from the liquid level storage means 7c. Then, to calculate a third liquid level _{H Z1} is the first liquid level _{H X1} midpoint of the second liquid level _{H Y1.} This operation is repeated a plurality of times (n times) at different liquid level (H _X2 , H _X3 ,... H _Xn ), and an average value H _Za of the obtained third liquid level is calculated. Then, the average value H _Za of the third liquid level is set to a liquid level corresponding to half of the total capacity of the liquid storage tank. That is, the liquid amount at the average value H _Za of the third liquid surface level is set to half of the total capacity of the liquid storage tank, and the liquid amount at the other liquid surface level is calculated from the liquid amount gradient data based on this. And calibrate.

  This completes the calibration of the data in that block. Here, when displaying the liquid amount for the liquid level in the block, the CPU 7a calculates and displays the liquid amount using a calibration conversion table that defines the relationship between the liquid level and the liquid amount after calibration. Set the program.

  Similarly, the block-unit data calibration processing is performed, and the calibration processing for all block data is completed. As described above, the data of each block is automatically reflected in the liquid amount display when the calibration process in the block is completed. Instead of automatically reflecting, it is also possible to set the program so that it is specified and reflected in units of blocks.

  INDUSTRIAL APPLICABILITY The present invention can be used in a system for grasping and managing the amount of liquid remaining in a liquid storage tank when measuring and selling from the liquid storage tank through a measuring machine.

1 is a system configuration diagram of a liquid amount management system of the present invention. It is a block diagram which shows the structure of the data collection means and liquid quantity display apparatus in the liquid quantity management system of this invention. It is a flowchart which shows the data acquisition process of the calibration process in the liquid quantity management system of this invention. It is a flowchart which shows the data processing process of the calibration process in the liquid quantity management system of this invention. It is a figure which shows the data format of the liquid quantity gradient data obtained at the data processing process of FIG. It is a figure which shows the data format of a conversion table. It is a flowchart which shows the calibration conversion table preparation process of the calibration process in the liquid quantity management system of this invention. It is a figure which shows the data format of the calibration conversion table obtained at the calibration conversion table preparation process of FIG. It is a figure which shows the relationship between the liquid level in a liquid storage tank with a substantially circular longitudinal cross-sectional shape, and a liquid quantity gradient.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid storage tank 2 Liquid level detector 3 Weighing machine 4 Liquid supply nozzle 5 Nozzle switch 6 Data collection means 6a Liquid level detector switching means 6b Data averaging / noise removal means 7 Liquid amount display device 7a CPU
7b Conversion table storage means 7c Liquid amount gradient storage means 7d Calibration conversion table storage means 7e Liquid amount display means 7f Printing means 7g Communication port 7h SS-LAN port 7i Input means 7j Instrumental difference data storage means 8 POS

Claims (4)

A liquid meter that is connected to the liquid storage tank, a liquid level detector that detects the liquid level of the liquid storage tank, and a conversion that defines the relationship between the liquid level and the liquid amount of the liquid storage tank In a liquid amount management system comprising a liquid amount display device that calculates and displays a liquid amount from a liquid level detected by the liquid level detector based on a table,
The liquid amount display device determines a liquid amount gradient (ΔQ /) from a liquid supply amount (ΔQ) supplied by the meter and a liquid level change (ΔH) before and after the liquid supply detected by the liquid level detector. ΔH) is calculated, and a liquid amount gradient storing means for storing this liquid amount gradient in association with one liquid level in the liquid level change is provided, and further corresponds to half of the total capacity of the liquid storage tank. The liquid level to be obtained is determined, and the liquid amount at the liquid level is set as half of the total capacity of the liquid storage tank. Based on this, each liquid level is stored based on the liquid amount gradient stored in the liquid amount gradient storage means. Calculate the liquid level after calibration at the surface level, create a calibration conversion table that defines the relationship between the liquid level of the liquid storage tank and the liquid amount after calibration, and based on this calibration conversion table The liquid volume was calculated from the display and displayed Liquid volume management system characterized and. A liquid meter that is connected to the liquid storage tank, a liquid level detector that detects the liquid level of the liquid storage tank, and a conversion that defines the relationship between the liquid level and the liquid amount of the liquid storage tank In a liquid amount management system comprising a liquid amount display device that calculates and displays a liquid amount from a liquid level detected by the liquid level detector based on a table,
The liquid amount display device corrects the weighing data with the instrumental error data of the weighing machine to obtain the liquid supply amount (ΔQ) supplied by the weighing machine, and detects the liquid supply amount and the liquid level detector. The liquid level gradient (ΔQ / ΔH) is calculated from the level change (ΔH) before and after the liquid supply, and this liquid level gradient is stored in association with one liquid level in the liquid level change. A liquid level gradient storage unit, and calculates a liquid level after calibration at the liquid level based on the liquid level gradient stored in the liquid level gradient storage unit; A liquid amount management system characterized in that a calibration conversion table for defining a relationship with the liquid amount is prepared, and the liquid amount is calculated from the liquid level based on the calibration conversion table and displayed. A liquid meter that is connected to the liquid storage tank, a liquid level detector that detects the liquid level of the liquid storage tank, and a conversion that defines the relationship between the liquid level and the liquid amount of the liquid storage tank In a liquid amount management system comprising a liquid amount display device that calculates and displays a liquid amount from a liquid level detected by the liquid level detector based on a table,
The liquid amount display device corrects the weighing data with the instrumental error data of the weighing machine to obtain the liquid supply amount (ΔQ) supplied by the weighing machine, and detects the liquid supply amount and the liquid level detector. The liquid level gradient (ΔQ / ΔH) is calculated from the level change (ΔH) before and after the liquid supply, and this liquid level gradient is stored in association with one liquid level in the liquid level change. A liquid level gradient storage means, further obtaining a liquid level corresponding to half of the total capacity of the liquid storage tank, and setting the liquid level at the liquid level as half of the total capacity of the liquid storage tank; Based on the liquid level gradient stored in the liquid level gradient storage means, the liquid level after calibration at each liquid level is calculated, and the liquid level of the liquid storage tank and the liquid level after calibration are calculated. Create a calibration conversion table that defines the relationship. Liquid volume management system is characterized in that as to calculate the liquid volume from the liquid level to display based on the table.   The longitudinal section of the liquid storage tank is substantially circular, the liquid volume gradient at the first liquid level below the diameter line of the liquid storage tank is extracted from the liquid volume gradient storage means, and the diameter of the liquid storage tank The second liquid level having the same liquid level gradient as the extracted liquid level gradient is extracted from the liquid level gradient storage means above the line, and the midpoint between the first liquid level and the second liquid level is extracted. The third liquid level is calculated, the operation is repeated a plurality of times at different liquid levels, the average value of the third liquid level is calculated, and the average liquid level of the third liquid level is calculated. The liquid quantity management system according to claim 1 or 3, wherein the liquid quantity at the level is set to half of the total capacity of the liquid storage tank.

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