Liquid Inventory Management System

Abstract

To cooperatively operate a liquid level detection device and a petroleum inventory control system that makes a determination based on analysis of inventory control data, etc., in order to compensate each other's disadvantages to achieve reliable and quick leakage detection and identification of a leakage area.SOLUTION: The petroleum inventory control system comprises: a magnetostrictive liquid level / water level sensor 9 that detects a liquid level and a water level inside a petroleum storage tank 4; a petroleum meter 17; a petroleum transport vehicle 28; injection amount information accumulation means 31; discharge amount information accumulation means 32; increase / decrease amount information accumulation means 33; rapid analysis means 34 that detects a petroleum leakage or a water contamination based on liquid amount information and water amount information transmitted from the magnetostrictive liquid level / water level sensor 9 in the latest 12 hours; detail analysis means 35 that detects the petroleum leakage etc. and identifies an abnormality occurrence area based on the information stored in each of the information accumulation means 31-33 in the latest 1 week; and petroleum storage tank state notification means 36 that notifies petroleum storage tank state information.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid inventory management system used to detect locations where abnormalities occur in a liquid injection system for injecting liquid into a liquid storage tank, such as an oil storage tank (usually an underground tank) installed at a gas station or the like, or a solvent storage tank installed at a chemical plant or the like, and a liquid discharge system for discharging liquid from the liquid storage tank.

Background Art

[0002] Conventionally, in order to detect leaks or the like in a liquid storage tank, a liquid inventory management system that determines based on analysis of various liquid level detection devices and inventory management data has been used. For example, as described in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2005-351767), the applicant has developed a magnetostrictive liquid level gauge that includes a first float for detecting the oil level in a liquid storage tank and a second float for detecting the water level, calculates whether the fluctuation of the liquid level per unit time is greater than or equal to a predetermined amount, and accurately detects whether water is accumulating in the liquid storage tank based on the calculation result and the detection result of the water level (see particularly paragraphs 0008 to 0011, 0017, and FIG. 1). Further, Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2016-156699) discloses an abnormality detection method and an abnormality detection device for detecting an abnormality in a fuel storage system at a service station (SS) that supplies fuel to a vehicle. Based on the injection amount from a tank truck (106) to a storage tank (102), the increase or decrease in the amount of fuel oil stored in the storage tank (102), and the dispensing amount from a meter (104) to the vehicle, etc., it describes determining the possibility of fuel leakage or water mixing and the location where it occurs (see particularly paragraphs 0022, 0032 to 0044, and FIG. 1). Furthermore, Patent Document 3 (Japanese Patent Application Laid-Open No. 2013-43648) describes a record book data in a gas station equipped with an underground tank (20) for storing fuel oil, statistical analysis data obtained by statistically processing the record book data, and liquid level fluctuation data when the fuel oil is stationary, and determines that there is a leakage of fuel oil in the underground tank when at least one of the record book data, the statistical analysis data, and the liquid level fluctuation data at rest is detected and notifies it (see particularly the abstract, paragraphs 0022, 0032 to 0055, and FIG. 1).

[0003] However, the liquid level detection device can only detect leaks in the liquid phase part of the underground storage tank, and cannot detect leaks in the gas phase part or pipes. The inventory management system that determines based on the analysis of inventory management data etc. can detect leaks from the underground storage tank, the fuel supply pipe, and the fuel injection pipe, but cannot identify the location where the leak is occurring. Conventionally, these devices and systems have been operated separately and there has been no cooperation between the two. And the invention described in Patent Document 1 accurately detects whether water is accumulated in the liquid storage tank, and there is no description regarding using the magnetostrictive liquid level gauge used in this invention for detecting leaks etc. in the liquid storage tank. Also, although Patent Document 2 describes determining the possibility of fuel leakage or water mixing and the location where it occurs in a fuel storage system, the oil level gauge (108) is only used to calculate the increase and decrease amount of the fuel oil stored in the storage tank (102). Furthermore, Patent Document 3 determines that there is a leakage of fuel oil in the underground tank when at least one of the record book data, the statistical analysis data, and the liquid level fluctuation data at rest is detected and notifies it, but each determination is independent, and no comprehensive determination of these data has been made, and no consideration has been given to which determination to prioritize for notification.

Prior Art Documents

Patent Documents

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 2005-351767 (Patent No. 4149963) Patent Document 2 Japanese Patent Application Laid-Open No. 2016-156699 (Patent No. 6497970) Patent Document 3 Japanese Patent Application Laid-Open No. 2013-43648 (Patent No. 5673437) SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] The problem of the present invention is to operate in cooperation with a liquid level detection device and an inventory management system that determines based on the analysis of inventory management data, etc., complement each other's drawbacks, and realize reliable and prompt leakage detection and identification of the location where an abnormality occurs. Specifically, by analyzing the liquid volume in the liquid storage tank, the liquid discharge amount from the liquid measuring device to a vehicle or the like, and the liquid injection amount into the liquid storage tank for a specific period or more, leakage from the liquid storage tank or piping can be detected, and the location where an abnormality occurs can be identified. At the same time, a highly accurate liquid level / water level sensor (for example, a magnetostrictive liquid level / water level sensor) is used to detect the liquid level and water level in the liquid storage tank, and a liquid inventory management system capable of detecting leakage from the liquid phase part of the liquid storage tank and the mixing of water into the liquid storage tank within a specific period is provided. MEANS FOR SOLVING THE PROBLEMS

[0006] The invention according to claim 1 for solving the above problems is a liquid inventory management system that detects leakage of the liquid stored in a liquid storage tank having a liquid discharge pipe and a liquid injection pipe or the mixing of water into the liquid storage tank, and notifies the state of the liquid storage tank, a liquid level / water level sensor installed in the liquid storage tank, which detects the liquid level of the stored liquid and the water level of the water accumulated at the bottom of the liquid storage tank every predetermined time, and transmits liquid volume information corresponding to the liquid level and water volume information corresponding to the water level; An injection amount information storage means for measuring the amount of liquid injected into the liquid storage tank, identifying whether injection is in progress, and recording the time and liquid volume from the start to the end of injection; A discharge amount information storage means for measuring the amount of liquid discharged from the liquid storage tank, identifying whether discharge is in progress, and recording the time and liquid volume from the start to the end of discharge; After measuring the initial liquid volume in the liquid storage tank, measuring the final liquid volume in the liquid storage tank after a predetermined period has elapsed, obtaining a calculated remaining liquid volume from the initial liquid volume and the liquid volume injected and discharged during the predetermined period, calculating an increase or decrease amount that is the absolute value of the difference between the calculated remaining liquid volume and the final liquid volume, and recording the measurement time and the increase or decrease amount; Based on the liquid volume information and water volume information transmitted from the liquid level / water level sensor within a most recent specific period, a rapid analysis means for detecting liquid leakage from the liquid storage tank or water mixing into the liquid storage tank and transmitting rapid analysis information; Based on the time and liquid volume from the start to the end of injection recorded in the injection amount information storage means, the time and liquid volume from the start to the end of discharge recorded in the discharge amount information storage means, and the measurement time and increase or decrease amount recorded in the increase or decrease amount information storage means over a most recent specific period or longer, a detailed analysis means for detecting liquid leakage from the liquid storage tank, the liquid discharge pipe, and the liquid injection pipe or water mixing into the liquid storage tank and specifying the location where an abnormality has occurred and transmitting detailed analysis information; A liquid storage tank state notification means for receiving the rapid analysis information transmitted from the rapid analysis means and the detailed analysis information transmitted from the detailed analysis means and notifying liquid storage tank state information based on the received rapid analysis information and detailed analysis information, and when the liquid storage tank state notification means receives quick analysis information and detailed analysis information from the quick analysis means and the detailed analysis means, it notifies liquid storage tank state information based on the detailed analysis information; when the liquid storage tank state notification means has not received detailed analysis information from the detailed analysis means and has received only quick analysis information from the quick analysis means, it notifies liquid storage tank state information based on the quick analysis information; also, even when the liquid storage tank state notification means has not received detailed analysis information from the detailed analysis means, it can notify liquid storage tank state information based on the quick analysis information. is characterized by this.

[0007] In order to solve the above problems, the invention according to claim 2 is the liquid inventory management system of the invention according to claim 1, The rapid analysis means detects leakage of the liquid from the liquid storage tank or mixing of water into the liquid storage tank based on the stable liquid volume information and stable water volume information transmitted from the liquid level / water surface sensor during a time period when there is no liquid discharge or injection. The increase / decrease amount information accumulation means measures the stable final liquid volume during a time period when there is no liquid discharge or injection, and calculates the increase / decrease amount, which is the absolute value of the difference between the calculated remaining liquid volume and the stable final liquid volume.

Advantages of the Invention

[0009] According to the invention according to claim 1 or 2, by operating in cooperation with a liquid inventory management system that determines based on analysis of a liquid level detection device and inventory management data, etc., the defects of each other can be complemented to achieve reliable and prompt leakage detection and identification of the leakage location. Specifically, by detecting the liquid volume and water volume in the liquid storage tank, it is possible to detect leakage from the liquid phase part of the liquid storage tank or mixing of water into the liquid storage tank within a specific period (usually within 1 day), and further, by analyzing the liquid volume in the liquid storage tank, the liquid discharge amount from the liquid meter, and the liquid injection amount into the liquid storage tank for a period longer than a specific period (usually 2 days or more), leakage from the liquid storage tank or piping can be detected and the location of the abnormality can be identified.

Figure 1

Brief Description of the Drawings

[0011]

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0012] Hereinafter, embodiments of the present invention will be described by way of examples. **Examples**

[0013] FIG. 1 is a block diagram of an oil inventory management system according to Example 1. As shown in FIG. 1, the oil inventory management system according to Example 1 has the following configuration. (1) An oil storage tank 4 having an oil discharge pipe 1 (also referred to as a “suction pipe”), an oil injection pipe 2, and a ventilation pipe 3. The oil discharge pipe 1 has a lid 5 that closes the branch end for inspection. A nozzle 6 is provided at the end of the oil injection pipe 2. The ventilation pipe 3 has a lid 7 that closes the branch end for inspection and a ventilation port 8 is provided at the end extending to the outside.

[0014] (2) A magnetostrictive liquid level and water level sensor 9 that detects the liquid level of the stored oil and the water level of the water accumulated at the bottom of the oil storage tank 4 every predetermined time (for example, every 1 second), and transmits liquid volume information corresponding to the liquid level and water volume information corresponding to the water level. The magnetostrictive liquid level and water level sensor 9 includes a detection unit 10 installed above the oil storage tank 4, a lead pipe 11 (metal pipe) extending from the lower part of the detection unit 10 to the bottom of the oil storage tank 4, a magnetostrictive wire 12 extending from the detection unit 10 to the lower end of the lead pipe 11, a vibration detection coil 13 provided at the upper end of the magnetostrictive wire 12, an upper float 14 and a lower float 15 that are slidable up and down on the outside of the lead pipe 11 and contain magnets, and a level information transmission unit 16 that transmits liquid volume information and water volume information corresponding to the detected liquid level and water level. Note that according to the magnetostrictive liquid level / water level sensor 9, depending on the generation position of the ultrasonic vibration pulse of the torsional strain generated in the magnetostrictive wire 12 due to the interaction between the pulse current supplied to the magnetostrictive wire 12 and the magnetic field by the magnet, the elapsed time from when the pulse current is supplied until a received pulse is obtained by the vibration detection coil 13 changes. When the specific gravity of the upper float 14 is made smaller than that of the stored petroleum and the specific gravity of the lower float 15 is made larger than that of the stored petroleum and smaller than that of water, the heights of the magnets built into the upper float 14 and the lower float 15 become heights corresponding to the liquid level and the water level respectively. Therefore, by measuring the above elapsed time, the accurate liquid level and water level can be measured, and the liquid volume information and water volume information corresponding to the liquid level and the water level can be acquired at any time.

[0015] (3) An oil meter 17 that can pump up the petroleum stored in the petroleum storage tank 4, discharge the petroleum to a vehicle, an oil container, etc., measure the amount of the discharged petroleum, and transmit the oil discharge amount information after the discharge is completed. And inside the oil meter 17, a pump 18 connected to one end of the oil discharge pipe 1 is provided, and a fuel supply hose 20 connected to the fuel supply nozzle 19 is drawn out on the side surface. During fuel supply, the amount of petroleum discharged from the fuel supply nozzle 19 is measured, and the discharged petroleum amount, etc. are displayed on the display unit 21 provided on the front surface. When the fuel supply is completed and the fuel supply nozzle 19 is returned to the nozzle holder 22, the oil discharge amount information is transmitted. Also, at the other end of the oil discharge pipe 1 (inside the petroleum storage tank 4), a water separator 23 is provided to prevent water, etc. from being mixed in when pumping up the petroleum in the tank.

[0016] (4) A manhole 24 that houses a part of the oil discharge pipe 1, the lid 5, the upper part of the ventilation pipe 3, the lid 7, the ventilation port 8, and the upper part of the magnetostrictive liquid level / water level sensor 9 (the upper part of the lead pipe 11, the upper part of the magnetostrictive wire 12, the vibration detection coil 13, and the level information transmission unit 16). And a detachable iron lid 25 is provided at the opening of the manhole 24. (5) An oil transport vehicle 28 such as a tank truck having an oil storage tank 26 for loading oil and an oil injection hose 27 for injecting the oil in the oil storage tank 26 into the oil storage tank 4. Note that a connector 29 is provided at the end of the oil injection hose 27, and the connector 29 can be easily detached from and attached to the base 6 at the end of the oil injection pipe 2. Therefore, oil can be injected into the oil storage tank 4 without leaking from the oil storage tank 26. (6) A POS terminal 30 composed of a card reader for reading credit cards, etc., a keyboard for data input, a display device for displaying data, etc., a printer for printing slips, etc., and a control device for controlling these. After receiving a fueling request signal from the fuel dispenser 17 and outputting a fueling permission signal, it performs settlement processing and sales management based on the oil discharge amount information transmitted from the fuel dispenser 17, and receives the liquid amount information and water amount information transmitted from the level information transmission unit 16 of the magnetostrictive liquid level / water level sensor 9 and the oil injection amount information transmitted from the metering transmission means of the oil transport vehicle 28, and manages the remaining amount in the tank, the injection amount from the oil transport vehicle 28, etc.

[0017] (7) An injection amount information accumulation means 31 that creates an injection flag Fi indicating whether injection is in progress based on the liquid amount information and water amount information transmitted from the level information transmission unit 16 of the magnetostrictive liquid level / water level sensor 9, determines the start and end of oil injection into the oil storage tank 4, and records the injection start time, the liquid amount at the start of injection, the injection end time, and the liquid amount at the end of injection in the injection memory. (8) A discharge amount information accumulation means 32 that creates a discharge flag Fd indicating whether discharge is in progress based on the discharge start signal, discharge end signal, and discharge amount SD transmitted from the fuel dispenser 17, and records the discharge start time, discharge end time, and discharge amount SD. (9) Based on the liquid volume information and water volume information transmitted from the level information transmission unit 16 of the magnetic distortion type liquid level and water surface sensor 9, after measuring the initial liquid volume in the oil storage tank 4, the final liquid volume in the oil storage tank 4 after a predetermined period has elapsed is measured. Based on the injection start time, the liquid volume at the start of injection, the injection end time, and the liquid volume at the end of injection recorded in the injection memory, and the discharge start time, the discharge end time, and the discharge volume SD recorded in the discharge memory, the remaining liquid volume is calculated from the initial liquid volume and the liquid volume injected and discharged during the predetermined period, and the increase or decrease amount, which is the absolute value of the difference between the calculated remaining liquid volume and the final liquid volume, is calculated, and the increase or decrease amount information storage means 33 records the measurement time and the increase or decrease amount in the increase or decrease amount memory.

[0018] (10) Within the most recent specific period (for example, 12 hours), based on the liquid volume information and water volume information received at each information acquisition interval Ta (for example, every 10 minutes), detect the leakage of oil from the oil storage tank 4 or the mixing of water into the oil storage tank 4, and transmit the rapid analysis information regarding the presence or absence of oil leakage and the presence or absence of water mixing. The rapid analysis means 34. (11) Based on the time and liquid volume from the start of injection to the end of injection recorded in the injection amount information storage means 31, the time and liquid volume from the start of discharge to the end of discharge recorded in the discharge amount information storage means 32, and the measurement time and increase or decrease amount recorded in the increase or decrease amount information storage means 33 over a period of the most recent specific period or more (for example, one week), detect the leakage of oil from the oil storage tank 4, the oil discharge pipe 1, and the oil injection pipe 2 or the mixing of water into the oil storage tank 4, and identify whether the abnormal occurrence location is any of the oil storage tank 4, the oil discharge pipe 1, and the oil injection pipe 2, and transmit the detailed analysis information regarding the presence or absence of oil leakage, the presence or absence of water mixing, and the abnormal occurrence location. The detailed analysis means 35. Note that the detailed analysis means 35 is installed in an analysis center or the like away from a gas station or the like, and information such as time, liquid volume, and increase or decrease amount is received via an appropriate communication line (the Internet line in FIG. 1). (12) Receive the rapid analysis information transmitted from the rapid analysis means 34 and the detailed analysis information transmitted from the detailed analysis means 35, and based on the received rapid analysis information and detailed analysis information, notify the oil storage tank state information. The oil storage tank state notification means 36.

[0019] Figure 2 is a flowchart of the processing procedure in the rapid analysis means 34 of Example 1. The processing determines and records whether there is an abnormality in the liquid volume and water volume in the oil storage tank 4 according to the following procedures 1 to 11. The following explains each procedure.

[0020] (Procedure 1) <Condition setting> Information acquisition interval Ta (minutes): for example, 10 minutes, short-term liquid volume fluctuation tolerance value LVS (liters / 10 minutes) for detecting sudden large-scale oil leakage, etc.: for example, 2 liters / 10 minutes, long-term liquid volume fluctuation tolerance value LVL (liters / hour) for detecting minute oil leakage, etc.: for example, 0.38 liters / hour, long-term water volume fluctuation tolerance value WVL (liters / hour) for detecting minute water leakage, etc.: for example, 0.38 liters / hour, and the number of information acquisitions J (times) required to detect minute oil or water leakage, etc. according to the tank capacity: for example, 7 times (the 7th information acquisition is 1 hour after the 1st information acquisition) are set, and proceed to Procedure 2. (Procedure 2) Reset the counter value n to an initial value of 1, and then proceed to Procedure 3. (Procedure 3) <Information acquisition every Ta elapse and acquisition of injection-in-progress flag and discharge-in-progress flag> Every time the information acquisition interval Ta elapses, after acquiring the nth time information Tn, liquid volume LVn, water volume WVn, and the injection-in-progress flag Fi and discharge-in-progress flag Fd that are respectively ON during oil injection and discharge, proceed to Procedure 4. Note that the injection-in-progress flag Fi and discharge-in-progress flag Fd are created in the injection volume information accumulation means 31 and discharge volume information accumulation means 32 mainly for accumulating information used in the detailed analysis means 35. The details will be described later. (Procedure 4) Determine whether the oil is not being injected and not being discharged according to whether the injection-in-progress flag Fi or discharge-in-progress flag Fd acquired in Procedure 3 is ON. If Yes, proceed to Procedure 5. If No (injection in progress or discharge in progress), return to Procedure 2.

[0021] (Step 5) Calculate the short-term liquid volume change amount LASn by computing the following Equation 1, and proceed to Step 6. LASn = |LVn - LV n-1 | ····· (Equation 1) (Step 6) If the short-term liquid volume change amount LASn is greater than or equal to the short-term liquid volume fluctuation tolerance value LVS, determine that there is an abnormality in the short-term liquid volume and proceed to Step 7. If it is less than the short-term liquid volume fluctuation tolerance value LVS, determine that the short-term liquid volume is normal and proceed to Step 7. (Step 7) If the counter value n has reached J, proceed to Step 8. If not, set n = n + 1 and then return to Step 3. (Step 8) Calculate the long-term liquid volume change amount LALn by computing the following Equation 2, calculate the long-term water volume change amount WALn by computing the following Equation 3, and proceed to Step 9. LALn = |LVn - LV 1 | ····· (Equation 2) WALn = |WVn - WV 1 | ····· (Equation 3) (Step 9) If the long-term liquid volume change amount LALn is greater than or equal to the long-term liquid volume fluctuation tolerance value LVL, determine that there is an abnormality in the liquid volume and proceed to Step 10. If it is less than the long-term liquid volume fluctuation tolerance value LVL, determine that the liquid volume is normal and proceed to Step 10. (Step 10) If the long-term water volume change amount WALn is greater than or equal to the long-term water volume fluctuation tolerance value WVL, determine that there is an abnormality in the water volume and proceed to Step 11. If it is less than the long-term water volume fluctuation tolerance value WVL, determine that the water volume is normal and proceed to Step 11. (Step 11) Record the short-term liquid volume change amount LASn, the long-term liquid volume change amount LALn, and the long-term water volume change amount WALn in the liquid volume and water volume memory, and then return to Step 2.

[0022] Figure 3 is a flowchart of the processing procedure in the injection amount information storage means 31 of Embodiment 1. The processing determines the start and end of the injection of oil into the oil storage tank 4 according to the following procedures I1 to I11, and records the injection start time and the liquid volume at the start of injection (pre-injection liquid volume DS), as well as the injection end time and the liquid volume at the end of injection (post-injection liquid volume DE). The following is an explanation of each procedure.

[0023] (Procedure I1) <Condition setting> Information acquisition interval Tb (seconds): For example, 10 seconds. The liquid volume measured by the magnetostrictive liquid level / water surface sensor 9 is checked at 10-second intervals. Injection start determination value PDS (liters / 10 seconds) for determining the start of injection into the tank: For example, 100 liters / 10 seconds and injection end determination value PDE (liters / 10 seconds) for determining the end of injection into the tank: For example, 50 liters / 10 seconds are set, and proceed to step I2. (Step I2) Reset the counter value n and the injection-in-progress flag Fi, set n to 1, Fi to OFF, and then proceed to step I3. (Step I3) [Information acquisition every Tb elapse] Every time the information acquisition interval Tb elapses, acquire the nth time information Tn and the nth liquid volume information Pn. (Step I4) Depending on whether the injection-in-progress flag Fi is OFF or ON, if Fi = OFF, proceed to step I5, and if Fi = ON, proceed to step I9.

[0024] (Step I5) Whether the absolute value of the value obtained by subtracting the (n - 1)th liquid volume information P n-1 from the nth liquid volume information Pn is greater than or equal to the injection start determination value PDS, that is, whether |Pn - P n-1 | ≥ PDS. If No, proceed to step I6, set n = n + 1, and then return to step I3. If Yes, proceed to step I7, set the injection-in-progress flag Fi to ON, and then proceed to step I8. (Step I8) The (n - 1)th time information T n-1 and liquid volume information P n-1 obtained in step I3 are recorded in the injection memory as the injection start time Tis and the pre-injection liquid volume DS respectively, proceed to step I6, set n = n + 1, and then return to step I3. (Step I9) Whether the absolute value of the value obtained by subtracting the (n - 1)th liquid volume information P n-1 from the nth liquid volume information Pn is less than or equal to the injection end determination value PDE, that is, whether |Pn - P n-1 | ≤ PDE. If No, proceed to step I6, set n = n + 1, and then return to step I3. If Yes, proceed to step I10, start the end timer, wait until timeout, and then proceed to step I11. (Step I11) Record the nth time information Tn and liquid volume information Pn obtained in Step I3 in the injection memory as the injection end time Tie and the post-injection liquid volume DE respectively, and return to Step I2.

[0025] Figure 4 is a flowchart of the processing procedure in the discharge amount information storage means 32 of the first embodiment. The processing determines the start and end of the discharge of oil from the oil storage tank 4 according to the following steps D1 to D11, and records the discharge start time Tds, the discharge end time Tde, and the discharge amount SD. The following describes each step.

[0026] (Step D1) <Condition setting> Set the information acquisition interval Tc (seconds): for example, set it to 1 second, and proceed to Step D2. (Step D2) Reset the counter value n and the discharge flag Fd. After setting n = 1 and turning off the discharge flag Fd, proceed to Step D3. (Step D3) <Information acquisition every Tc elapses> Every time the information acquisition interval Tc elapses, acquire the nth time information Tn, and proceed to Step D4. (Step D4) Depending on whether the discharge flag Fd is OFF or ON, if Fd is OFF, proceed to Step D5, and if Fd is ON, proceed to Step D9.

[0027] (Step D5) Determine whether a discharge start signal has been received from the oil meter 17. If not, proceed to Step D6, set n = n + 1, and then return to Step D3. If the signal has been received, proceed to Step D7, turn on the discharge flag Fd, and then proceed to Step D8. (Step D8) Record the nth time information Tn obtained in Step D3 in the discharge memory as the discharge start time Tds, return to Step D6, set n = n + 1, and then return to Step D3. (Step D9) Determine whether a discharge end signal has been received from the oil meter 17. If not, return to Step D6, set n = n + 1, and then return to Step D3. If the signal has been received, proceed to Step D10, acquire the information on the discharge amount SD from the oil meter 17, and proceed to Step D11. (Procedure D11) Set the nth time information Tn obtained in Procedure D3 as the discharge end time Tde, record it in the discharge memory together with the discharge amount SD obtained in Procedure D10, and return to Procedure D2.

[0028] Then, based on the injection start time Tis, the pre-injection liquid volume DS, the injection end time Tie, and the post-injection liquid volume DE recorded in the injection memory in processing steps I8 and I11 of the injection amount information accumulation means 31, and the discharge start time Tds, the discharge end time Tde, and the discharge amount SD recorded in the discharge memory in processing steps D8 and D11 of the discharge amount information accumulation means, calculate the cumulative discharge amount SA, which is the sum of the discharge amounts SD discharged between the injection start time Tis and the injection end time Tie. Calculate the injection increase / decrease amount DVA by calculating the following formula 4, and record the injection start time Tis, the injection end time Tie, and the injection increase / decrease amount DVA in the injection memory in association with each other. DVA = DE - DS + SA ····· (Formula 4)

[0029] Figure 5 is a flowchart of the processing procedure in the increase / decrease amount information accumulation means 33 of Example 1. In this process, various information is acquired each time the information acquisition interval Td set by the following procedures Z1 to Z11 is reached. Calculate the increase / decrease amount AID, which is the absolute value of the difference between the calculated remaining liquid volume LVC and the actual liquid volume LV, and record the increase / decrease amount AID together with the information acquisition time Te in the increase / decrease amount memory. The following is an explanation of each procedure.

[0030] (Procedure Z1) <Condition setting> Set the information acquisition interval Td (hours): For example, set it to 4 hours, and proceed to Procedure Z2. (Procedure Z2) Reset the information acquisition timer and proceed to Procedure Z3. (Procedure Z3) <Acquisition of initial information> Acquire the initial time information T0 and the initial liquid volume information LV0 at the time when the information acquisition timer is reset, and proceed to Procedure Z4. (Procedure Z4) Determine whether the information acquisition timer has reached the information acquisition interval Td. If it has not reached, repeat Procedure Z4. If it has reached, proceed to Procedure Z5. (Procedure Z5) Depending on whether the injection-in-progress flag Fi and the discharge-in-progress flag Fd created in the injection quantity information storage means 31 and the discharge quantity information storage means 32 are acquired or not, it is determined whether the oil is not being injected and not being discharged. If No (injecting or discharging), procedure Z5 is repeated. If Yes, proceed to procedure Z6.

[0031] (Procedure Z6) <Acquisition of Various Information> When the information acquisition timer times out and the oil is neither being injected nor being discharged, the end time information Te and the end liquid volume information LVe at that time are acquired. Also, based on the information recorded in the injection memory, the cumulative injection volume DVC of the oil at the information acquisition interval Td is calculated, and based on the information recorded in the discharge memory, the cumulative discharge volume SVC of the oil at the information acquisition interval Td is calculated, and then proceed to procedure Z7. (Procedure Z7) <Calculation of Calculated Remaining Liquid Volume> The calculated remaining liquid volume LVC is calculated by operating the following formula 5, and then proceed to procedure Z8. LVC = LV0 + DVC - SVC ····· (Formula 5) (Procedure Z8) <Calculation of Increase / Decrease Amount> The increase / decrease amount AID is calculated by operating the following formula 6, and then proceed to procedure Z9. AID = |LVe - LVC| ······· (Formula 6) (Procedure Z9) Record the initial time T0, end time Te, end liquid volume LVe, cumulative injection volume DVC, cumulative discharge volume SVC, calculated remaining liquid volume LVC, and increase / decrease amount AID acquired or calculated in procedures Z3 and Z6 - Z8 in the increase / decrease amount memory, return to procedure Z2, and perform the processing for the next information acquisition interval.

[0032] Figure 6 is a flowchart of the processing procedure in the detailed analysis means 35 of Example 1. The processing starts at an arbitrary timing and, according to the following procedures A - L, when reaching the set analysis interval Rp, acquires various data for the most recent d days of analysis data, determines whether there are abnormalities in various increase / decrease amounts, liquid volumes, and water volumes, makes a comprehensive determination based on those determination results, identifies the locations where abnormalities occur in the oil storage tank 4, pipes, etc., and ends the processing. The following explains each procedure.

[0033] (Procedure A) <Condition Setting> Set the analysis interval Rp (time): for example, 24 hours, the number of analysis data days d (days): for example, 10 days, the allowable increase / decrease value As (%): for example, 1% of the cumulative discharge amount during the acquisition period of each increase / decrease amount AID, the long-term liquid volume change allowable value Ls (liters / hour): for example, the average value during the acquisition period of each increase / decrease amount AID is 0.38 liters / hour, the long-term water volume change allowable value Ws (liters / hour): for example, 0.38 liters / hour, and the injection increase / decrease allowable value Ds (%): for example, 2% of the cumulative discharge amount during the acquisition period of each increase / decrease amount AID, and proceed to Procedure B. (Procedure B) Reset the data acquisition timer and proceed to Procedure C. (Procedure C) Determine whether the data acquisition timer has reached the analysis interval Rp. If it has not reached, repeat Procedure C. If it has reached, proceed to Procedure D. (Procedure D) <Data Acquisition for the Most Recent d Days> Obtain the increase / decrease amount AID for the most recent d days from the increase / decrease memory, the long-term liquid volume change amount LALn and the long-term water volume change amount WALn recorded in the liquid volume / water volume memory during the acquisition period of each increase / decrease amount AID, the injection increase / decrease amount DVA recorded in the injection memory, the discharge start time Tds, the discharge end time Tde, and the discharge amount SD recorded in the discharge memory, and proceed to Procedure E.

[0034] (Procedure E) If the ratio of the increase / decrease amount AID during the acquisition period of each increase / decrease amount AID to the sum of the discharge amounts SD during the same period is equal to or greater than the allowable increase / decrease value As, it is determined that there is an abnormality in the increase / decrease amount AID and proceed to Procedure F. If it is less than As, it is determined that there is no abnormality in the increase / decrease amount AID and proceed to Procedure F. (Procedure F) If the average value of the long-term liquid volume change amount LALn during the acquisition period of each increase / decrease amount AID is equal to or greater than the long-term liquid volume change allowable value Ls, it is determined that there is an abnormality in the long-term liquid volume change amount LALn and proceed to Procedure G. If it is less than Ls, it is determined that there is no abnormality in the long-term liquid volume change amount LALn and proceed to Procedure G. (Step G) If the average value of the long-term water volume change amount WALn during the acquisition period of each increase / decrease amount AID is equal to or greater than the long-term water volume change allowable value Ws, it is determined that there is an abnormality in the long-term water volume change amount WALn, and the process proceeds to Step H. If it is less than Ws, it is determined that there is no abnormality in the long-term water volume change amount WALn, and the process proceeds to Step H. (Step H) If the ratio of the average value of the injection increase / decrease amount DVA during the acquisition period of each increase / decrease amount AID to the sum of the discharge amounts SD during the same period is equal to or greater than the injection increase / decrease amount allowable value Ds, it is determined that there is an abnormality in the injection increase / decrease amount DVA, and the process proceeds to Step I. If it is less than Ds, it is determined that there is no abnormality in the injection increase / decrease amount DVA, and the process proceeds to Step I.

[0035] (Step I) For the acquisition periods of all the increase / decrease amounts AID in the most recent d days, after the determinations in Steps E to H are completed, the determination results for the increase / decrease amount AID, the long-term liquid volume change amount LALn, the long-term water volume change amount WALn, and the injection increase / decrease amount DVA are recorded in the determination result memory, and the process proceeds to Step J. (Step J) Based on all the determination results recorded in the determination result memory in Step I, a comprehensive determination is made, and the oil injection pipe 2, the oil storage tank 4, the oil meter 17, etc. are specified as the locations where abnormalities occur, and the process ends. The following explains the determination examples in the comprehensive determination. (Determination Example 1) If AID, LALn, and WALn are normal and only DVA has an abnormality, it is determined that there is an abnormality in the oil injection pipe 2. (Determination Example 2) If AID, LALn, and DVA are normal and only WALn has an abnormality, it is determined that there is an abnormality in the oil storage tank 4. (Determination Example 3) If LALn, WALn, and DVA are normal and only AID has an abnormality, it is determined that there is an abnormality in the oil meter 17.

[0036] As described above, the rapid analysis means 34 of Example 1 determines the presence or absence of short-term liquid volume abnormalities each time the information acquisition interval Ta elapses according to Steps 3 to 6, and determines the presence or absence of liquid volume and water volume abnormalities each time the J-th information is acquired according to Steps 7 to 10. When it is determined that there is any abnormality and when the process ends and the determination results are recorded in the liquid volume / water volume memory, the rapid analysis information is transmitted to the oil storage tank status notification means 36. In addition, as described in Procedures E to H, the detailed analysis means 35 of Example 1 determines the presence or absence of abnormalities in the increase / decrease amount AID, long-term liquid volume change amount LALn, long-term water volume change amount WALn, and injection-time increase / decrease amount DVA during the acquisition period of each increase / decrease amount AID. As described in Procedures I and J, all the determination results are recorded in the determination result memory, and a comprehensive determination is performed based on all the determination results. Piping 2 for oil injection, oil storage tank 4, oil meter 17, etc. are specified as the locations where abnormalities occur, detailed analysis information is created, and the rapid analysis information is transmitted to the oil storage tank status notification means 36. Upon receiving the rapid analysis information transmitted from the rapid analysis means 34 and the detailed analysis information transmitted from the detailed analysis means 35, the oil storage tank status notification means 36 notifies the oil storage tank status information based on the detailed analysis information when both the rapid analysis information and the detailed analysis information are received, and notifies the oil storage tank status information based on the rapid analysis information when only the rapid analysis information is received. As a mode of notification, it is displayed as characters on the screen, but in addition to the characters, the abnormal location may be displayed in a diagram, or further, voice notification may be added.

Example

[0037] Example 2 has all the configurations of Example 1 and adds a water level monitoring means. FIG. 7 is a flowchart of the processing procedure in the water level monitoring means of Example 2. The processing acquires information such as the water level each time the information acquisition interval Tc set by the following Procedures W1 to W6 is reached. When it is determined that there is an abnormal water level and the water level determination result is recorded in the liquid volume / water volume memory, and when the water level determination result is recorded and the processing ends, information indicating whether there is an abnormal water level or not is transmitted to the oil storage tank status notification means 36. Hereinafter, each procedure will be described. Since the configurations other than the water level monitoring means are the same as those of Example 1, the description thereof is omitted.

[0038] (Procedure W1) <Condition setting> Information acquisition interval Tc (seconds): For example, 1 second. Water level abnormal determination value WLs (mm) for detecting an increase in the water level due to the accumulation of moisture in the oil storage tank 4: For example, 35 mm is set, and the process proceeds to Procedure W2. (Procedure W2) Information acquisition for each Tc period Every time the information acquisition interval Tc elapses, after obtaining the water level WL, the injection flag Fi, and the discharge flag Fd, proceed to Procedure W3. (Procedure W3) Determine whether the oil is not being injected and not being discharged according to whether the injection flag Fi or the discharge flag Fd obtained in Procedure 2 is ON. If Yes, proceed to Procedure W4; if No (injection or discharge), return to Procedure W2.

[0039] (Procedure W4) If the water level WL is equal to or higher than the water level abnormality determination value WLs, determine that there is a water level abnormality and proceed to Procedure W5; if it is less than WLs, determine that the water level is normal and proceed to Procedure W5. (Procedure W5) If it is determined in Procedure W4 that there is a water level abnormality, record the determination result of "water level abnormality" in the liquid volume and water volume memory, and transmit the information of "water level abnormality" to the oil storage tank status notification means 36, and then return to Procedure W2. Also, if it is determined in Procedure W4 that the water level is normal, record the determination result of "water level normal" in the liquid volume and water volume memory, and transmit the information of "water level normal" to the oil storage tank status notification means 36, and then return to Procedure W2. And the oil storage tank status notification means 36 that has received the information of "water level abnormality" from the water level monitoring means immediately notifies that the water level in the oil storage tank 4 is rising. Therefore, according to the oil inventory management system according to Embodiment 2, since the rise in the water level due to the water gradually accumulating in the oil storage tank 4 is constantly detected in an amount less than the long-term water volume fluctuation allowable value WVL, the staff at a gas station or the like can be quickly notified of the water level abnormality in the oil storage tank 4 due to such a rise in the water level.

[0040] List modification examples of the oil inventory management system according to Embodiments 1 and 2. (Modification Example 1) Embodiments 1 and 2 are oil inventory management systems, but they may also be inventory management systems for solvents and the like used not only in oil but also in chemical factories and the like. Therefore, the name is a liquid inventory management system, and in the claims, "oil" for each component is changed to "liquid". (Modification Example 2) In the first and second embodiments, the oil storage tank 4 had the ventilation pipe 3, but instead of the ventilation pipe 3, a ventilation hole may be provided on the upper surface of the oil storage tank 4. (Modification Example 3) In the first and second embodiments, the magnetostrictive liquid level / water level sensor 9 was used, but any highly accurate liquid level / water level sensor may be used instead of the magnetostrictive liquid level / water level sensor. (Modification Example 4) In the first and second embodiments, the rapid analysis means 34 and the oil storage tank state notification means 36 were installed at a gas station or the like, and the detailed analysis means 35 was installed at an analysis center or the like away from the gas station or the like. However, the rapid analysis means 34, the detailed analysis means 35, and the oil storage tank state notification means 36 may all be installed at a gas station or the like to form an integrated type, or the rapid analysis means 34 and the detailed analysis means 35 may be installed at an analysis center or the like, and the oil storage tank state notification means 36 may be installed at a gas station or the like.

[0041] (Modification Example 5) In the injection amount information accumulation means 31 of the first and second embodiments, in procedures I5 and I7, if |Pn - P n-1 | ≥ PDS, the injection flag Fi is set to ON, and in procedures I9 to I11 and I2, if |Pn - P n-1 | ≤ PDE, the injection flag Fi is set to OFF. However, if an injection start signal is transmitted from the oil transport vehicle 27 and the signal is received, the injection flag Fi may be set to ON, and if the signal is not received, the injection flag Fi may be set to OFF. (Modification Example 6) In the injection amount information accumulation means 31 of the first and second embodiments, the pre-injection liquid amount DS was recorded in the injection memory in procedure I8, and the post-injection liquid amount DE was recorded in the injection memory in procedure I11. However, the injection amount may be transmitted from the oil transport vehicle 27, and instead of the pre-injection liquid amount DS and the post-injection liquid amount DE, the transmitted injection amount may be recorded in the injection memory.

[0042] (Modification Example 7) In the discharge amount information accumulation means 32 of the first and second embodiments, it is determined whether a discharge start signal is received from the oil meter 17 in procedures D5 and D7. If the signal is received, the process proceeds to procedure D7 to turn on the discharge flag Fd. In procedure D8, the discharge start time Tds is recorded in the discharge memory. In procedures D9 to D11 and D2, it is determined whether a discharge end signal is received from the oil meter 17. If the signal is received, the discharge amount SD is recorded in the discharge memory together with the discharge end time Tde, and the discharge flag Fd is turned off. However, in procedure D1, the discharge start determination value SDS and the discharge end determination value SDE are set. In procedure D3, the nth time information Tn is acquired, and the nth liquid volume information Pn is acquired. In procedure D5, it is determined whether |Pn - P n-1 |≥SDS. If Yes, the process proceeds to procedure D7 to turn on the discharge flag Fi. In procedure D8, the liquid volume before discharge is recorded in the discharge memory together with the discharge start time Tds. In procedure D9, if |Pn - P n-1 |≤SDE, the liquid volume after discharge may be recorded in the discharge memory together with the discharge end time Tde in procedure D11, and the discharge flag Fd may be turned off in procedure D2.

[0043] (Modification Example 8) The detailed analysis means 35 of the first and second embodiments performs a comprehensive determination based on all the determination results recorded in the determination result memory, and identifies the oil injection pipe 2, the oil storage tank 4, the oil meter 17, etc. as the locations where abnormalities occur. However, it may also notify which of the oil injection system, the oil storage tank, and the oil discharge system is the location where the abnormality occurs. Conversely, the discharge amount may be measured for each of the multiple oil meters, or the injection amount may be measured for each oil transport vehicle to be dispatched, and it may also be possible to identify which oil meter or oil transport vehicle is the cause.

Explanation of Reference Numerals

[0044] 1 Oil discharge pipe 2 Oil injection pipe 3 Vent pipe 4 Oil storage tank 5 Lid 6 Base 7 Lid 8 Vent hole 9 Magnetostrictive liquid level / water level sensor 10 Detection unit 11 Lead pipe 12 Magnetostrictive wire 13 Vibration detection coil 14 Upper float 15 Lower float 16 Level information transmission unit 17 Oil meter 18 Pump 19 Fuel nozzle 20 Fuel hose 21 Display unit 22 Nozzle hanger 23 Water separator 24 Manhole 25 Iron cover 26 Oil storage tank 27 Oil injection hose 28 Oil transport vehicle 29 Connector 30 POS terminal 31 Injection volume information storage means 32 Discharge volume information storage means 33 Increase / decrease volume information storage means 34 Quick analysis means 35 Detailed analysis means 36 Oil storage tank status notification means

Claims

1. A liquid inventory management system that detects leakage of a liquid stored in a liquid storage tank having a liquid discharge pipe and a liquid injection pipe or entry of water into the liquid storage tank, and notifies the state of the liquid storage tank, a liquid level / water level sensor installed in the liquid storage tank, which detects the liquid level of the stored liquid and the water level of the water accumulated at the bottom of the liquid storage tank at predetermined intervals, and transmits liquid volume information corresponding to the liquid level and water volume information corresponding to the water level; an injection volume information accumulation means that measures the amount of liquid injected into the liquid storage tank, identifies whether injection is in progress, and records the time and liquid volume from the start to the end of injection; a discharge volume information accumulation means that measures the amount of liquid discharged from the liquid storage tank, identifies whether discharge is in progress, and records the time and liquid volume from the start to the end of discharge; after measuring the initial liquid volume in the liquid storage tank, measuring the final liquid volume in the liquid storage tank after a predetermined period has elapsed, obtaining a calculated remaining liquid volume from the initial liquid volume and the liquid volume injected and discharged during the predetermined period, calculating the increase / decrease amount, which is the absolute value of the difference between the calculated remaining liquid volume and the final liquid volume, and recording the measurement time and the increase / decrease amount; a rapid analysis means that detects leakage of liquid from the liquid storage tank or entry of water into the liquid storage tank based on the liquid volume information and water volume information transmitted from the liquid level / water level sensor within a recent specific period, and transmits rapid analysis information; a detailed analysis means that detects leakage of liquid from the liquid storage tank, the liquid discharge pipe, and the liquid injection pipe or entry of water into the liquid storage tank based on the time and liquid volume from the start to the end of injection recorded in the injection volume information accumulation means, the time and liquid volume from the start to the end of discharge recorded in the discharge volume information accumulation means, and the measurement time and increase / decrease amount recorded in the increase / decrease amount information accumulation means over a recent specific period or longer, and identifies the location where the abnormality occurred, and transmits detailed analysis information; a liquid storage tank state notification means that receives the rapid analysis information transmitted from the rapid analysis means and the detailed analysis information transmitted from the detailed analysis means, and notifies liquid storage tank state information based on the received rapid analysis information and detailed analysis information, and the liquid storage tank state notification means is When receiving the rapid analysis information and the detailed analysis information from the rapid analysis means and the detailed analysis means, the liquid storage tank state information is notified based on the detailed analysis information. When not receiving the detailed analysis information from the detailed analysis means and only receiving the rapid analysis information from the rapid analysis means, the liquid storage tank state information is notified based on the rapid analysis information. A liquid inventory management system characterized by the above.

2. The rapid analysis means detects leakage of liquid from the liquid storage tank or mixing of water into the liquid storage tank based on the stable liquid volume information and the stable water volume information transmitted from the liquid level / water surface sensor during a time period when there is no liquid discharge or injection. The increase / decrease amount information accumulation means measures the stable final liquid volume during a time period when there is no liquid discharge or injection, and calculates the increase / decrease amount, which is the absolute value of the difference between the calculated remaining liquid volume and the stable final liquid volume. The liquid inventory management system according to claim 1, characterized by the above.

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