JP3879999B2 - 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. However, there is a problem in 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.
JP-A-1-163621

  The first problem to be solved by the present invention is to manage the amount of liquid that can reduce the fluctuation of calibration data due to environmental changes such as temperature changes and perform highly accurate calibration processing sufficient for practical use in a short period of time. To provide a system. A second problem is to provide a liquid amount management system capable of preventing the execution of calibration processing using inadvertent data.

  In calibrating the conversion table that defines the relationship between the liquid level of the liquid storage tank and the liquid amount, the liquid supply amount (ΔQ) supplied by the weighing machine and the supply detected by the liquid level detector are used. A liquid volume gradient (ΔQ / ΔH) is calculated from the change in liquid level before and after the liquid (ΔH), and calibration processing is performed using the liquid volume gradient data. Specifically, a liquid level gradient is linked to one liquid level in the change in the liquid level, and a liquid level after calibration at the liquid level is calculated based on the liquid level gradient, and the liquid storage tank A calibration conversion table for defining the relationship between the liquid level and the liquid amount after calibration is created, and the liquid amount is calculated from the liquid level based on the calibration conversion table and displayed.

  In the present invention, in order to prevent the calibration process from being performed unintentionally and to improve the accuracy of the calculated liquid level gradient, the liquid level is changed only when the liquid level change exceeds a plurality of liquid level intervals. It is preferable to calculate a quantity gradient.

  Further, in the present invention, in order to quickly reflect the result of the calibration process, in the created calibration conversion table, the liquid level is managed by dividing it into a plurality of blocks, and all the liquid level in the block are managed. When the calculation of the liquid volume after calibration based on the liquid volume gradient is completed, the calculation of the liquid volume after calibration (calibration processing) based on the liquid volume gradient is not completed in another block. With respect to the liquid level to which it belongs, the liquid amount can be calculated and displayed based on the calibration conversion table.

  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.

  Also, when collecting the liquid level gradient data, the liquid level gradient is calculated only when the change in the liquid level exceeds a plurality of liquid level levels, so that the accuracy of the calculated liquid level gradient can be improved. In addition, it is possible to prevent the execution of calibration processing with careless data.

  In the created calibration conversion table, the liquid level is divided into multiple blocks and managed, and the calculation of the liquid level after calibration based on the liquid volume gradient is completed for all the liquid level in the block In addition, by calculating and displaying the liquid level based on the calibration conversion table for the liquid level belonging to the block, calculation of the liquid level after calibration (calibration) based on the liquid volume gradient in other blocks. Even if the processing is not completed, the calibration data can be used sequentially from the block where the calibration processing is completed, so that the result of the calibration processing can be reflected quickly.

  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 And a calibration conversion table storage means 7d for storing the calibration conversion table.

  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. The CPU 7a is connected to a printing unit 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 conversion table storage unit 7b, and the liquid amount gradient storage unit 7c. In addition, various data stored in the calibration conversion table storage means 7d can be printed or confirmed by connecting a personal computer or the like.

  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, liquid supply amount data is acquired from the weighing machine 3.

  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 ± 0.1 ° C. When the above-described temperature change exceeds ± 0.1 ° 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 ± 0.1 ° C., the data is valid, and the liquid level gradient G (ΔQ / ΔH) is calculated from the liquid level change (ΔH) and the supply amount (ΔQ) to the CPU 7a (FIG. 2). 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 following formula: 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 the liquid volume gradient data is all 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, the liquid amount is set at a certain liquid surface level, and the liquid amount at the other liquid surface level is calculated and calibrated from the liquid amount gradient data based on this. 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.

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 8 POS

Claims (3)

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 change in liquid level before and after the liquid supply detected by the liquid level detector (ΔH). [Delta] H) is calculated, and a liquid volume gradient storage means for storing the liquid volume gradient in association with one liquid level in the liquid level change is provided, and the liquid volume gradient stored in the liquid volume gradient storage means The liquid level after calibration at the liquid level is calculated on the basis of the liquid level, and a calibration conversion table that defines the relationship between the liquid level of the liquid storage tank and the liquid level after calibration is created. A liquid volume management system characterized in that the liquid volume is calculated from the liquid level and displayed.   The liquid quantity management system according to claim 1, wherein the liquid quantity gradient is calculated only when the change in the liquid level exceeds a plurality of liquid level levels.   In the calibration conversion table, the liquid level is divided into a plurality of blocks, and when the calculation of the liquid amount after calibration based on the liquid amount gradient is completed for all the liquid level in the block, The liquid level management system according to claim 1 or 2, wherein the liquid level to which the liquid level belongs is calculated and displayed based on the calibration conversion table.

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