Liquid level sensors, liquid level management systems, methods, and programs

Abstract

This aims to simplify liquid level detection and management of the remaining liquid volume, as well as simplify maintenance. [Solution] The system includes a sensor housing 42 installed in the tank 16, an ultrasonic transmitting / receiving unit (ultrasonic transducer 4) that transmits ultrasonic waves toward the surface of the contained liquid (kerosene 18) and receives reflected waves from the liquid surface, a temperature sensor 20, a power supply unit 12 including a battery 26, a sensor information generation unit (control unit 8) which has set operating times of at least two times per day or approximately per day, operates the ultrasonic transmitting / receiving unit during each operating time, measures distance using ultrasonic waves, and generates sensor information including the distance along with one or more of the following: tank information, battery voltage, and detected temperature, and an information transmission unit (communication unit 10) that transmits the sensor information.

Description

Technical Field

[0001] The present disclosure relates to a liquid level sensor for detecting a liquid level such as a kerosene level in a kerosene tank, a method for liquid level management, and a program.

Background Art

[0002] Kerosene used as fuel for heating, hot water supply, etc. is stored and consumed in a kerosene tank, and its remaining amount monitoring and replenishment are continuously managed. Since the kerosene monitoring of the kerosene tank and the kerosene replenishment are carried out by delivery from a storage base, the kerosene monitoring or the kerosene replenishment is extremely important, and the stable supply of kerosene is an issue.

[0003] Regarding a kerosene supply system, an integrated flow meter is installed in a supply pipe for supplying kerosene from a kerosene tank to each consumer, the increment of the integrated flow within a required time is measured and integrated for each consumer, and it is known to notify the management center of kerosene replenishment (for example, Patent Document 1).

[0004] Regarding the remaining amount monitoring of a kerosene tank, it is known that a server receives measurement values from a plurality of measuring instruments, determines whether the value of the fluid amount represented by this measurement value has reached a predetermined value, and outputs a signal indicating those among the plurality of measuring instruments whose determination result is affirmative (for example, Patent Document 2).

[0005] Regarding the detection of the remaining amount of a stored substance such as kerosene in a storage tank, it is known that a detection device includes a detection unit for detecting the stored substance from an opening of the storage tank, a storage unit for storing the detection result, a transmission unit for transmitting the detection result, and a coupling unit for coupling to the opening of the storage tank (for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

[0007] Incidentally, in managing kerosene stored in tanks and consumed from those tanks, monitoring the kerosene level in the tank is essential. The kerosene level can be detected by a sensor, and the remaining amount of kerosene can be determined from that detected level. In this type of kerosene remaining amount management, the sensor is installed facing the kerosene inside the tank. Therefore, there is a challenge in that the sensor is affected by the volatility of kerosene. For this reason, the sensor needs to be highly resistant to kerosene.

[0008] The sensors installed alongside the kerosene tank pose management problems because they can be easily operated by anyone other than the administrator, and they also have other challenges, such as the need for sufficient resistance to damage from wild animals.

[0009] If the area where kerosene is consumed is, for example, a cold region or a heavy snowfall area, automation is desirable to reduce the effort required to detect the kerosene level or to acquire detection information, and continuous recording and accumulation of detection information is essential for kerosene management.

[0010] These challenges are not limited to kerosene; they also apply to liquid level detection and management for other liquids such as drinking water.

[0011] Therefore, the purpose of this disclosure is to simplify maintenance, as well as facilitate the detection of the liquid level of the liquid contained in the tank and the management of the remaining amount of liquid, based on the above-mentioned problems. [Means for solving the problem]

[0012] To achieve the above objective, according to one aspect of the liquid level sensor of this disclosure, the sensor includes: a sensor housing installed at the opening of a tank; an ultrasonic transmitting / receiving unit that transmits ultrasonic waves from the sensor housing toward the liquid surface of the liquid contained in the tank and receives reflected ultrasonic waves from the liquid surface in the sensor housing; a temperature sensor that detects the internal or external temperature of the sensor housing; a power supply unit including a battery; a sensor information generation unit which operates the ultrasonic transmitting / receiving unit during each operating time, which measures the distance between the ultrasonic transmission point and the liquid surface or the distance between the reflected wave reception point and the liquid surface, and generates sensor information which includes tank information representing the tank, the distance, and one or more of the battery voltage and detected temperature; and an information transmission unit which transmits the sensor information.

[0013] In this liquid level sensor, the sensor may further include a substrate on which the ultrasonic transmitting and receiving unit is mounted, a surrounding unit that supports the substrate and separates it from the tank side, enclosing the ultrasonic element and exposing the ultrasonic transmitting or receiving unit of the ultrasonic element to the tank side, and a protective unit that protects the ultrasonic transmitting and receiving unit, the power supply unit, the sensor information generation unit, and the information transmission unit.

[0014] In this liquid level sensor, a shielding membrane may be provided to surround the ultrasonic element and prevent the liquid contained in the sensor housing from penetrating from the tank side.

[0015] In this liquid level sensor, the ultrasonic transmitting and receiving unit may further include a short-range mode for transmitting low-level ultrasonic waves and a long-range mode for transmitting high-level ultrasonic waves, and the sensor information generation unit may execute the short-range mode or the long-range mode and generate sensor information including the distance, the number of times the short-range mode or the long-range mode is executed and execution information.

[0016] In this liquid level sensor, the ultrasonic transmitting and receiving unit includes an ultrasonic transducer having a transmitting element that transmits the ultrasonic waves toward the liquid surface and a receiving element that receives the reflected waves of the ultrasonic waves from the liquid surface, and the ultrasonic waves may have a frequency of 300 kHz, a value close to that, or a frequency exceeding 300 kHz.

[0017] In this liquid level sensor, a startup unit may be provided that receives a magnetic force from outside the sensor housing and activates the ultrasonic transmitting / receiving unit and the sensor information generation unit when this magnetic force is above a threshold.

[0018] In this liquid level sensor, the contained liquid may be kerosene or a liquid containing kerosene.

[0019] To achieve the above objective, according to one aspect of the liquid level management system of this disclosure, the system includes a tank, a liquid level sensor which has set operating times of at least two times per day or nearly per day, during each operating time it transmits ultrasonic waves toward the liquid surface of the liquid contained in the tank, receives reflected waves of the ultrasonic waves from the liquid surface, measures the distance between the ultrasonic transmission point or the reflected wave reception point and the liquid surface, and transmits sensor information including, along with the distance, tank information representing the tank, battery voltage, and detected temperature (one or more of these), a sensor information storage unit which acquires and stores the sensor information transmitted by the liquid level sensor as needed, and a liquid level management unit which periodically or irregularly acquires the sensor information from the sensor information storage unit and, when the remaining liquid in the tank reaches the level requiring replenishment, generates alert information and / or replenishment instruction information associated with the identification information of the tank and notifies a delivery company terminal.

[0020] In this management system, the liquid level management unit may further associate tank information representing the tank with customer information representing the customer, and present to the customer terminal any or more of the remaining amount of liquid in the tank, the replenishment instruction information including the delivery date and time of the liquid, and the replenishment result information.

[0021] To achieve the above object, according to one aspect of the liquid level management method of the present disclosure, an operating time of at least twice a day or approximately twice a day is set for a liquid level sensor installed at an opening of a tank. At each operating time, ultrasonic waves are transmitted from a sensor housing toward a liquid surface of a liquid stored in the tank, a reflected wave of the ultrasonic waves from the liquid surface is received, a distance between a transmission point of the ultrasonic waves or a reception point of the reflected wave and the liquid surface is measured, and sensor information including any one or two or more of tank information representing the tank, battery voltage, and detected temperature is transmitted together with the distance. A step of a sensor information storage unit acquiring and storing the sensor information from the liquid level sensor, and a step of a liquid level management unit periodically or irregularly acquiring the sensor information from the sensor information storage unit, and when the remaining amount of the liquid stored in the tank reaches a replenishment required level, generating replenishment instruction information associated with identification information of the tank and notifying either or both of a customer terminal and a delivery business operator terminal are included.

[0022] In this liquid level management method, further, the liquid level management unit may include a step of associating tank information representing the tank with customer information representing a customer and presenting any one or two or more of remaining amount information of the liquid stored in the tank, the replenishment instruction information including the delivery date and time of the liquid, and replenishment result information to the customer terminal.

[0023] In this liquid level management method, further, a step of installing the liquid level sensor that is activated by receiving a magnetic force equal to or greater than a threshold value, and a step of applying a magnetic force to the liquid level sensor to activate it may be included.

[0024] To achieve the above object, according to one aspect of the program of the present disclosure, there is provided a program for causing a computer system to execute. The program is configured such that the operating time is set to at least twice a day or approximately once a day. At each operating time, ultrasonic waves are transmitted towards the liquid level of the liquid stored in the tank, and the reflected waves of the ultrasonic waves from the liquid level are received. The distance between the ultrasonic wave transmission point or the reflected wave reception point and the liquid level is measured, and sensor information including any one or more of the tank information representing the tank, the battery voltage, and the detected temperature is transmitted together with the distance. The program further includes functions for acquiring the sensor information and storing it in a sensor information storage unit, periodically or irregularly acquiring the sensor information from the sensor information storage unit, generating replenishment instruction information associated with the identification information of the tank when the remaining amount of the liquid stored in the tank reaches the replenishment required level, and notifying a delivery operator terminal.

[0025] In this program, the computer system may further be caused to execute a function of associating the tank information representing the tank with the customer information representing the customer, and presenting any one or more of the remaining amount information of the liquid stored in the tank, the replenishment instruction information including the delivery date and time of the liquid, and the replenishment result information to a customer terminal.

Advantages of the Invention

[0026] According to the present disclosure, any of the following effects can be obtained. (1) It is possible to facilitate the detection of the liquid level of the liquid stored in the tank and the management of the remaining amount of the liquid, simplify maintenance, or even achieve maintenance-free operation.

[0027] (2) If a sensor housing is installed at the opening of the tank to activate the liquid level sensor, the operating time is set to at least twice a day or approximately once a day. At each operating time, the distance from the sensor housing to the liquid level can be automatically measured by transmitting ultrasonic waves and receiving the reflected waves of the ultrasonic waves from the liquid level. Together with this distance, sensor information including any one or more of the detected temperature, tank information, and battery voltage can be generated and transmitted.

[0028] (3) Using the sensor information transmitted from this tank, the remaining amount of liquid in the tank, the timing of replenishment of the liquid, and the operating status of the liquid level sensor can be easily managed unattended. [Brief explanation of the drawing]

[0029] [Figure 1] This is a block diagram showing a liquid level sensor according to the first embodiment. [Figure 2] This is a flowchart showing the procedure for processing sensor information. [Figure 3] Figure 3A shows the sensor information, and Figure 3B is a flowchart of the process for activating the liquid level sensor. [Figure 4] Figure 4A is a partial cross-sectional view showing the tank, and Figure 4B is a cross-sectional view showing the liquid level sensor. [Figure 5] This is a disassembled cross-sectional view of the liquid level sensor. [Figure 6] This is a block diagram showing a liquid level management system according to a second embodiment. [Figure 7] This figure shows an example of a sensor information database. [Figure 8] This figure shows an example of a liquid level management information database. [Figure 9] This is a flowchart showing the procedure for processing sensor information. [Figure 10] This flowchart shows the procedure for managing the liquid level. [Modes for carrying out the invention]

[0030] [First Embodiment] Figure 1 shows a liquid level sensor 2 according to a first embodiment. This liquid level sensor 2 is an example of the present disclosure, and the present disclosure is not limited to the configuration shown in Figure 1. This liquid level sensor 2 includes an ultrasonic transducer 4, an ultrasonic drive unit 6, a control unit 8, a communication unit 10, a power supply unit 12, and the like.

[0031] The ultrasonic transducer 4 is an example of an ultrasonic transmitting and receiving unit of this disclosure. This ultrasonic transducer 4 comprises a transmitting element 14-1 and a receiving element 14-2. The transmitting element 14-1 is an ultrasonic element that transmits ultrasonic waves Si toward the liquid surface of kerosene 18, which is an example of a liquid contained in a tank 16, and the receiving element 14-2 is an ultrasonic element that receives reflected waves Sr from the liquid surface of kerosene 18. Ultrasonic waves with a frequency of 300 kHz, a value close to that, or a frequency exceeding 300 kHz are used for the ultrasonic waves Si.

[0032] The ultrasonic drive unit 6 is controlled by the control unit 8, which generates and transmits ultrasonic waves Si by the transmitting element 14-1 and performs signal conversion of the reflected wave Sr received by the receiving element 14-2. The electrical signal obtained by the receiving element 14-2 is then taken up by the control unit 8.

[0033] The control unit 8 is an example of a sensor information generation unit of this disclosure. It receives the output of the ultrasonic drive unit 6, calculates the distance D from the ultrasonic Si transmission point (or reception point) to the liquid surface of the kerosene 18, and generates sensor information including this distance D.

[0034] Here, if we let Δt (=t2-t1) be the time difference from the transmission time t1 of the ultrasonic wave Si to the reception time t2 of the reflected wave Sr, v be the velocity of the ultrasonic wave Si, and D be the distance from the transmission point of the ultrasonic wave Si (=reception point of the reflected wave Sr) to the surface of the kerosene 18, then the time difference Δt is proportional to the propagation distance, so the distance D [m] can be expressed by Equation 1.

[0035] D=v·Δt / 2 [m] (Formula 1)

[0036] By the way, since the liquid level sensor 2 measures kerosene 18 in tank 16, the distance D from the ultrasonic Si transmission point (or reception point) to the liquid surface of the kerosene 18 fluctuates within the depth of tank 16 where the kerosene 18 is stored (for example, a depth of about 1 m).

[0037] Therefore, in this embodiment, the liquid level sensor 2 is equipped with a short-range mode and a long-range mode to improve the detection accuracy of the reflected wave Sr and the measurement accuracy of the distance D. In other words, a constant measurement accuracy is maintained within the range of variation of the distance D by using both the short-range mode and the long-range mode. The short-range mode is a measurement mode for distances of approximately 50 cm, and uses low-level ultrasonic Si to transmit and receive for, for example, four times. The long-range mode is a measurement mode for distances of approximately 1 m, and uses high-level ultrasonic Si to repeat transmission and reception for, for example, four times. Normally, measurements are taken in short-range mode, and when measurement is not possible in short-range mode, the system automatically switches to long-range mode and continues distance measurement.

[0038] The control unit 8, which is responsible for this processing and control, is composed of, for example, a microcomputer. This control unit 8 includes a processor (for example, a Central Processing Unit: CPU), memory, an input / output unit (I / O), a timer, etc. After startup, this CPU executes information processing such as the OS (Operating System) and the liquid level detection program for the contained liquid such as kerosene 18 stored in memory, and controls the ultrasonic drive unit 6 and the communication unit 10, etc. The timer may be composed of the control unit 8, or it may be provided separately from the control unit 8.

[0039] The memory includes storage elements such as ROM (Read-Only Memory) and RAM (Random-Access Memory). ROM stores the OS, a program for detecting the liquid level of the contained liquid (such as kerosene 18), and a database. RAM constitutes the work area for information processing.

[0040] The timer is monitored by the processor for operating time and sets, for example, at least two operating times per day or approximately per day. During each operating time, the ultrasonic drive unit 6, the control unit 8, and the communication unit 10 operate.

[0041] The control unit 8 is equipped with a temperature sensor 20. This temperature sensor 20 detects the substrate temperature of the liquid level sensor 2 and provides the control unit 8 with temperature information that affects the ultrasonic Si of the transmitting element 14-1, the reflected Sr of the receiving element 14-2, and so on.

[0042] The control unit 8 is always connected to the power supply unit 12 and is activated by the activation unit 22. The activation unit 22 can activate the control unit 8 when a magnetic force exceeding a threshold level is applied from outside the liquid level sensor 2 (i.e., during initial setup).

[0043] The communication unit 10 is an example of an information transmission unit in this disclosure that transmits sensor information. Under the control of the control unit 8, the communication unit 10 generates a transmission signal that includes sensor information output by the control unit 8. This transmission signal, including the transmission radio waves, is transmitted from the antenna 24 to the base station at any time. In this case, the transmission mode is two transmissions per day.

[0044] The power supply unit 12 includes a battery 26 and a boost power supply unit 28. The battery 26 is a battery that outputs a constant voltage, for example, a lithium-ion battery. The boost power supply unit 28 is composed of, for example, a boost DC-DC converter, which boosts the output voltage of the battery 26 to, for example, the rated voltage required to drive the ultrasonic drive unit 6.

[0045] <Information processing of the control unit 8> The information processing by the control unit 8 includes control such as startup and initial setup, setting and operation of operating time, execution of short-range mode or acquisition of output information for either short-range mode, execution of long-range mode, acquisition of output information for long-range mode, calculation of distance D, acquisition of voltage information, acquisition of temperature information, generation and transmission of sensor information.

[0046] a) Startup and initial setup: After the liquid level sensor 2 is installed, when a magnetic force exceeding a threshold level is applied to the startup unit 22, the control unit 8 starts up due to conductivity in, for example, a Hall element installed in the startup unit 22.

[0047] b) Setting and operation of operating time: The control unit 8 receives the timer output and sets the operating time twice per day. The operating time for each operation is a few seconds, which is the period during which ultrasonic Si is transmitted and reflected wave Sr is received, distance D is calculated, and sensor information including distance D, substrate temperature T, and sensor ID is generated and transmitted.

[0048] c) Execution of short-range mode: When the operating time begins, the short-range mode is preferentially executed. In short-range mode, the control unit 8 controls the oscillation and transmission of low-level ultrasonic Si from the transmitting element 14-1, and the number of transmissions is, for example, 4.

[0049] The reflected wave Sr generated from the liquid surface of the kerosene 18 enters the receiving element 14-2, is converted into an electrical signal (received signal) of a level corresponding to the reflected wave Sr, and is taken into the control unit 8.

[0050] d) Acquisition of output information for short-range mode: The control unit 8 acquires output information such as the received signal for short-range mode, mode information indicating short-range mode, and the number of transmissions.

[0051] e) Execution of long-range mode: If output information cannot be obtained in short-range mode, the system switches to long-range mode. In long-range mode, the control unit 8 controls the oscillation and transmission of high-level ultrasonic Si from the transmitting element 14-1, and the number of transmissions is the same as in short-range mode. Since short-range mode is prioritized and the system switches to long-range mode only when measurement is not possible in short-range mode, power consumption can be reduced and the battery 26 can be depleted.

[0052] f) Acquisition of output information in long-distance mode: The control unit 8 acquires output information such as the received signal in long-distance mode, mode information representing long-distance mode, and the number of transmissions.

[0053] g) Calculation of distance D: The control unit 8 determines the time difference Δt (=t2-t1) from the time of transmission of ultrasonic waves Si t1 to the time of reception of reflected waves Sr t2, using either the short-range mode or the long-range mode, and uses the velocity v of ultrasonic waves Si to determine the distance D from the transmission point of ultrasonic waves Si (=reception point of reflected waves Sr) to the liquid surface of kerosene 18 from equation 1 described above.

[0054] h) Acquisition of voltage information: Since the control unit 8 receives battery voltage from the battery 26, it detects the battery voltage of the battery 26 during operation and acquires this as voltage information representing the power supply capacity of the battery 26.

[0055] i) Acquisition of temperature information: The control unit 8 acquires temperature information representing the internal and external temperatures of the liquid level sensor 2 by detecting the substrate temperature with the temperature sensor 20.

[0056] j) Generation and transmission of sensor information: The liquid level sensor 2 is assigned a sensor ID as identification information to identify the liquid level sensor 2. The control unit 8 generates sensor information including the calculated distance D, execution mode information representing short-range mode or long-range mode, the number of mode executions, battery voltage V, board temperature T, and sensor ID, and outputs this sensor information to the communication unit 10. The communication unit 10 transmits the sensor information received from the control unit 8 via radio waves from the antenna 24 to a relay unit 78 (Figure 6) or base station associated with the management server.

[0057] <Processing Procedure> Figure 2 shows an example of a processing procedure representing the information processing of the control unit 8. This processing procedure is an example of a liquid level management method or program of the present disclosure. In Figure 2, S is an example of a process, and the numbers assigned to S indicate an example of the process sequence, but the present disclosure is not limited to this process and process sequence.

[0058] This processing procedure includes initial setup (S101), determination of operating time (S102), execution of short-range mode (S103), determination of acquisition of output information for short-range mode (S104), execution of long-range mode (S105), calculation of distance D (S106), acquisition of temperature information (S107), acquisition of voltage information (S108), acquisition of sensor ID information (S109), generation of sensor information (S110), transmission of sensor information (S111), determination of the end of operating time (S112), and so on.

[0059] When the control unit 8 is activated, initial settings (S101) are performed and the timer is started. The timer is set to a unit of one day (=24 hours) or approximately one day, for example, with two operating times ta and tb set. Each operating time ta and tb occurs with an approximately 12-hour period, and each operating time ta and tb is the time that allows for the repetition of four ultrasonic Si transmissions and reflected Sr receptions, as described above.

[0060] The control unit 8 monitors the arrival of each operating time ta and tb (S102), and for example, when operating time ta or operating time tb arrives, it prioritizes executing the short-range mode (S103). It determines whether low-level ultrasonic Si transmission and reflected wave Sr reception have occurred and whether output information for this short-range mode has been acquired (S104).

[0061] If output information cannot be obtained after executing the short-range mode (NO in S104), the system switches to the long-range mode (S105). In this long-range mode, high-level ultrasonic Si is transmitted and reflected Sr is received, and the output information from this long-range mode is taken up by the control unit 8.

[0062] The control unit 8 uses either the output information acquired in short-range mode or the output information acquired in long-range mode to determine the time difference Δt between the transmission time t1 of the ultrasonic Si and the reception time t2 of the reflected wave Sr, and calculates the distance D from Equation 1 using the time difference Δt and the velocity v of the ultrasonic Si (S106).

[0063] Furthermore, the control unit 8 acquires temperature information representing the substrate temperature T (S107), voltage information representing the battery voltage V (S108), and sensor ID (S109), generates sensor information including these (S110), and transmits this sensor information from the communication unit 10 (S111).

[0064] The control unit 8 then determines whether the operating time has ended (S112). The control unit 8 repeats the processes from S103 to S112 until the operating time has ended, at which point it terminates this process and switches to power-saving mode to wait until the next operating time arrives.

[0065] <Sensor Information> Figure 3A shows the sensor information generated by the control unit 8. This sensor information includes the tank ID at operating time ta or operating time tb, distance D, mode information indicating the short-range or long-range mode used to measure distance D, the number of measurements in each mode, temperature information representing the substrate temperature T, and voltage information representing the battery voltage V. This sensor information may also be configured to include, for example, one or more of the following along with distance D: sensor ID, mode information, number of measurements, temperature information representing the substrate temperature T, and battery voltage V.

[0066] <Startup process for liquid level sensor 2> Figure 3B shows the startup process for the liquid level sensor 2. This startup process is performed when installing or maintaining the liquid level sensor 2. This sequence of operations is an example of a liquid level management method or program of this disclosure. In Figure 3B, S is an example of a process, and the number assigned to S indicates an example of the sequence of operations; however, this disclosure is not limited to this process and sequence of operations.

[0067] This processing procedure includes shipping the liquid level sensor 2 (S201), installing it (S202), entering sleep mode (S203), determining the magnetic force level (S204), activating the liquid level sensor 2 (S205), starting the timer's timing operation (S206), and monitoring the operating times ta and tb (S207).

[0068] At the factory (S201), the liquid level sensor 2 is shipped with waterproofing treatment applied, and this liquid level sensor 2 is installed in the tank 16 at the point of demand for kerosene 18. In this installed state, the liquid level sensor 2 is maintained in sleep mode (S203). In this sleep mode (S203), the control unit 8 is connected to the power supply unit 12, but is maintained in standby mode in power-saving mode, and the liquid level sensor 2 is activated by a magnetic force applied to the activation unit 22, and the system transitions to timer operation. In other words, a magnetic force is applied to the activation unit 22 from outside the liquid level sensor 2, and if the magnetic force exceeds the threshold (magnetic force < threshold) (NO in S204), the sleep mode (S203) is maintained, and if the magnetic force exceeds the threshold (magnetic force > threshold) (YES in S204), the liquid level sensor 2 is activated (S205), and the system transitions to timer timing operation (S206). The timing operation of this timer measures the operating time of the liquid level sensor 2, and the liquid level sensor 2 can be monitored at intervals of the operating time (S207).

[0069] <Tank 16> Figure 4A shows a tank 16 with a portion cut out. The configuration of the tank 16 is an example, and this disclosure is not limited to such a configuration. This tank 16 is assigned a tank ID as identification information to identify the tank 16 separately from the liquid level sensor 2.

[0070] This tank 16 has, for example, a tank body 30 that holds kerosene 18, and is equipped with multiple legs 32, for example, four legs 32 that keep the tank body 30 away from the ground 34.

[0071] The ceiling portion 36 of the tank body 30 is provided with a ventilation section 38 and an opening 40. The inside of the tank body 30 is maintained at atmospheric pressure by the ventilation section 38.

[0072] The opening 40 is used for refilling kerosene 18 and can be opened and closed using the sensor housing 42. This sensor housing 42 is equipped with a liquid level sensor 2.

[0073] <Partial cross-section of tank 16 and cross-section of liquid level sensor 2> Figure 4B shows a cross-section of the liquid level sensor 2, and Figure 5 shows an exploded cross-section of the liquid level sensor 2.

[0074] The tank 16 is provided with a protrusion 44, and an opening 40 is formed in this protrusion 44. The cylindrical portion 46 of the sensor housing 42 can be attached to and detached from the outer circumference of this protrusion 44 by a threaded portion 49.

[0075] The sensor housing 42 comprises a cylindrical portion 46 and a lid portion 48, with the cylindrical portion 46 and the lid portion 48 forming a sealed space with a shielding member 50 interposed between them. The shielding member 50 is made of, for example, a silyl group-containing polymer and a fluorine coating agent, and prevents water from entering the sensor housing 42 during rainfall or snowfall, and kerosene from entering due to being doused with kerosene during refueling. An O-ring may be used for the shielding member 50, but in cold regions, one made of a cold-resistant material is preferable.

[0076] A closure portion 52 is formed in the cylindrical portion 46 to close the opening 40 of the tank 16, and substrate support portions 54-1 and 54-2 are formed in this closure portion 52 to support the first wiring board 58-1. The wiring board 58-1 is an example of the substrate portion of this disclosure, and is fixed to the substrate support portions 54-1 and 54-2 with screws 60-1 and supported by the substrate support portions 54-1 and 54-2 in the closure portion 52. An ultrasonic transducer 4, an ultrasonic drive unit 6, etc. are mounted on the wiring board 58-1.

[0077] The closed section 52 has a cylindrical enclosure 56-1 surrounding the transmitting element 14-1 and a cylindrical enclosure 56-2 surrounding the receiving element 14-2. The wiring board 54 supported by the closed section 52 has the transmitting element 14-1 mounted at a position corresponding to the enclosure 56-1 and the receiving element 14-2 mounted at a position corresponding to the enclosure 56-2. The transmitting element 14-1 is positioned and protected by the enclosure 56-1, and the ultrasonic transmitting part of the transmitting element 14-1 is exposed from the enclosure 56-1 toward the liquid surface of the kerosene 18. The receiving element 14-2 is positioned and protected by the enclosure 56-2, and the ultrasonic receiving part of the receiving element 14-2 is exposed from the enclosure 56-2 toward the liquid surface of the kerosene 18.

[0078] An adhesive layer 61 is formed between the transmitting element 14-1 and the surrounding portion 56-1, and between the receiving element 14-2 and the surrounding portion 56-2. The adhesive layer 61 is formed, for example, with an adhesive containing a silyl group polymer. Between the transmitting element 14-1 and the receiving element 14-2 and the wiring board 58-1, for example, a silyl group polymer is filled, and an adhesive layer 61 is formed.

[0079] A fluororesin layer 62 with good ultrasonic conductivity is formed on the transmitting surface of the transmitting element 14-1 and the receiving surface of the receiving element 14-2. The fluororesin layer 62 does not obstruct the passage of ultrasonic waves, but covers the transmitting surface of the transmitting element 14-1 and the receiving surface of the receiving element 14-2, forming a shielding film that prevents the penetration of kerosene 18 or other gases, which are examples of liquids contained in the tank 16. This shielding film can avoid the effect of condensation on ultrasonic measurements.

[0080] A second wiring board 58-2 is fixed and supported by screws 60-2 to the substrate support portions 64-1 and 64-2 formed on the lid portion 48. The wiring board 58-2 is an example of a substrate portion of this disclosure on which the control unit 8, power supply unit 12, startup unit 22, etc. are mounted. A battery 26 is installed between the electrode portions 66-1 and 66-2 on the back of the wiring board 58-2.

[0081] A smaller diameter section 68 is formed at the upper end of the cylindrical section 46, and a larger diameter section 70 corresponding to this smaller diameter section 68 is formed at the opening of the lid section 48. An O-ring mounting section 72 for installing the shielding member 50 is formed in the lid section 48, and the shielding member 50 installed in this O-ring mounting section 72 is gripped between the cylindrical section 46 and the lid section 48, forming a sealed space in the sensor housing 42. Therefore, the cylindrical section 46 and the lid section 48 constitute a protective section that protects the ultrasonic drive unit 6, the control unit 8, and the power supply unit 12.

[0082] <Effects of the First Embodiment> According to this first embodiment, one of the following effects can be obtained. (1) This liquid level sensor 2 makes it easier to detect the liquid level of kerosene 18 and manage the remaining amount, and simplifies or eliminates maintenance.

[0083] (2) By installing the liquid level sensor 2 at the opening 40 of the tank 16 and activating it, an operating time of 12 hours or approximately twice a day is set, and during each operating time, ultrasonic waves Si can be automatically transmitted and reflected waves Sr from the kerosene 18 can be automatically received, and the distance D to the kerosene 18 can be measured with high accuracy.

[0084] (3) Sensor information including distance D, tank ID, detected temperature, and battery voltage can be transmitted from the liquid level sensor 2 and acquired by the relay unit 78 described later.

[0085] (4) The liquid level sensor 2 is configured with a short-range mode for transmitting low-level ultrasonic waves Si and receiving their reflected waves Sr, and a long-range mode for transmitting high-level ultrasonic waves Si and receiving their reflected waves Sr. The distance D between the ultrasonic wave transmission point (or the reflected wave Sr reception point) and the liquid surface of the kerosene 18 can be detected multiple times in each mode, thereby improving the accuracy of the distance D measurement.

[0086] (5) For short-range mode, long-range mode and the number of measurements performed, for example, the mode m and the number of measurements n can be represented by two-digit numerical information mn, where the tens digit m indicates "1" for short-range mode and "2" for long-range mode, and the units digit n indicates the number of successful measurements out of 4. When mn = 14 or 24, it can represent 4 successful measurements in short-range mode and 4 successful measurements in long-range mode, and the mode and measurement status can be determined using this numerical information.

[0087] (6) The long-range mode generates more ultrasonic pulses and a larger current compared to the short-range mode, resulting in higher power consumption. Therefore, the short-range mode is a low-power mode and is used as the normal mode, while the long-range mode, which is a high-power mode, is used when measuring the liquid level is difficult in the short-range mode. In this embodiment, the switching from the short-range mode to the long-range mode is performed automatically, and the short-range mode is used as the normal mode, thereby reducing power consumption and suppressing the depletion of the battery 26. Furthermore, if the mode is changed from the short-range mode to the long-range mode and measurement becomes difficult in the long-range mode, this status information can also be used as information indicating that the battery 26 is depleted or that there is a malfunction in the sensor function.

[0088] (7) By using ultrasonic waves with a frequency of 300 kHz, near that value, or higher than 300 kHz for the ultrasonic Si, the reception accuracy of the reflected wave Sr can be improved.

[0089] (8) By applying a magnetic force to the activation unit 22 with a magnet or the like, and when the magnetic force is above a threshold, the liquid level sensor 2 can be activated from sleep state to operating state without contact. The sensor housing 42 of the liquid level sensor 2 can be configured with a thoroughly waterproof structure, eliminating the need for opening and closing windows for typical switch operation, and eliminating the need to open and close the sensor housing 42 for activation. This prevents the battery 26 from being consumed from the time of shipment until activation, extending the life of the battery 26. Furthermore, since activation requires a magnetic force above a threshold, the liquid level sensor 2 will not be activated unintentionally, extending the life of the battery 26 and improving the reliability of the liquid level sensor 2.

[0090] (9) The sensor housing 42 is configured by separating it into a cylindrical portion 46 and a lid portion 48. The cylindrical portion 46 is provided with a closing portion 52 to which the first wiring board 58-1 is attached, and the lid portion 48 is provided with a second wiring board 58-2. A sealing member such as a shielding member 50 is provided between the cylindrical portion 46 and the lid portion 48, and the cylindrical portion 46 and the lid portion 48 are combined to form a protective section with the sensor housing 42. This makes it possible to protect the ultrasonic drive unit 6, control unit 8, communication unit 10, power supply unit 12, etc.

[0091] (10) The closure portion 52 formed in the cylindrical portion 46 is provided with a surrounding portion 56-1 that surrounds the transmitting element 14-1 and exposes the ultrasonic transmitting portion, and a surrounding portion 56-2 that surrounds the receiving element 14-2 and exposes the ultrasonic receiving portion, and a fluororesin layer 62 is provided between the surrounding portion 56-1 and the transmitting element 14-1, and a fluororesin layer 62 is provided between the surrounding portion 56-2 and the receiving element 14-2, so that each fluororesin layer 62 functions as a shielding film that prevents the penetration of kerosene 18, and thus prevents deterioration of the ultrasonic transducer 4 and the wiring boards 58-1 and 58-2 due to kerosene 18 over time.

[0092] [Second Embodiment] Figure 6 shows a liquid level management system 74 according to the second embodiment. In Figure 6, the same parts as in Figure 1 are denoted by the same reference numerals.

[0093] A liquid level management system 74 is provided as an example of a liquid level management system, method, and program of this disclosure. This liquid level management system 74 includes a management server 76 and a relay unit 78, and individually manages the kerosene 18 in each tank 16-1, 16-2, ..., 16-n by acquiring sensor information from multiple liquid level sensors 2-1, 2-2, ..., 2-n. The management server 76 is an example of a liquid level management unit of this disclosure.

[0094] The management server 76 and the relay unit 78 are each composed of computers and are equipped with a processor, input / output unit, memory, communication unit, etc. The relay unit 78 is installed between each liquid level sensor 2-1, 2-2, ..., 2-n and the management server 76, and stores the sensor information sent from each liquid level sensor 2-1, 2-2, ..., 2-n in memory and provides it to the management server 76. In other words, it relays sensor information between each liquid level sensor 2-1, 2-2, ..., 2-n and the management server 76.

[0095] The relay unit 78 is equipped with memory, and a sensor information database (hereinafter referred to as "sensor information DB") 79 is installed in this memory. Sensor information from each liquid level sensor 2-1, 2-2, ..., 2-n stored in the sensor information DB 79 is provided to the management server 76 in response to access by the management server 76.

[0096] The management server 76 is equipped with memory, which stores a liquid level management information database (hereinafter referred to as the "liquid level management information DB") 80. This liquid level management information DB 80 stores liquid level management information that manages the remaining amount of kerosene 18 and its replenishment for each tank 16-1, 16-2, ..., 16-n using sensor information acquired from the relay unit 78.

[0097] The management server 76 is connected to customer terminals 82-1, 82-2, ..., 82-n and delivery company terminal 84, enabling the exchange of information such as alert information and delivery instruction information between these customer terminals 82-1, 82-2, ..., 82-n and delivery company terminal 84.

[0098] <Processing at relay unit 78> The information processing in the relay unit 78 includes acquiring sensor information, storing sensor information, and providing sensor information to the management server 76.

[0099] Sensor information acquisition: The relay unit 78 acquires sensor information randomly transmitted from each liquid level sensor 2-1, 2-2, ..., 2-n.

[0100] Sensor information storage: The relay unit 78 stores the acquired sensor information in the sensor information DB 79 and updates the stored contents.

[0101] Providing sensor information to the management server 76: The relay unit 78 receives access from the management server 76, provides sensor information to the management server 76, and records the access in the sensor information DB 79.

[0102] <Processing by Management Server 76> The information processing of the management server 76 includes acquiring sensor information, storing sensor information and customer information, calculating the remaining amount of kerosene 18 in tanks 16-1, 16-2, ..., 16-n, generating alert information, creating delivery plans, and recording performance information.

[0103] Sensor information acquisition: The management server 76 accesses the relay unit 78 at a set sensor information acquisition timing and acquires sensor information.

[0104] Storage of sensor information and customer information: The management server 76 associates the tank ID with the customer ID of the sensor information obtained from the relay unit 78, sorts the sensor information by customer ID, stores it in the liquid level management information DB 80, and updates it.

[0105] Calculation of remaining kerosene 18: The management server 76 calculates the remaining amount for each tank 16-1, 16-2, ..., 16-n, identified by the tank ID, and monitors the trend of the remaining amount. This monitoring includes determining whether the remaining amount of kerosene 18 has reached the level requiring replenishment.

[0106] Alert Information Generation: The management server 76 generates alert information when the remaining amount of kerosene 18 reaches or is expected to reach the level requiring replenishment. This alert information is transmitted from the communication unit to one or all of the customer terminals 82-1, 82-2, ..., 82-n, which correspond to the customer ID associated with the tank ID.

[0107] Creation of delivery plan: Based on the calculation of the remaining amount of kerosene 18, the management server 76 creates a delivery plan for kerosene 18 for each tank 16-1, 16-2, ..., 16-n, which is identified by the tank ID, taking into account consumption trends, etc. This delivery plan is provided to the delivery company terminal 84 and is also distributed as delivery plan information to the corresponding customer terminals 82-1, 82-2, ..., 82-n.

[0108] Recording of delivery results: The management server 76 receives notifications such as delivery results from the delivery company terminal 84 and records them as delivery results in the liquid level management information DB 80.

[0109] <Sensor Information DB79> Figure 7 shows an example of the sensor information DB 79. This sensor information DB 79 stores a date and time information unit 86, a sensor information unit 88, and an access record unit 90, among others. The date and time information unit 86 stores time information indicating the daily or approximately daily operating time ta and tb for liquid level sensors 2-1, 2-2, ..., 2-n.

[0110] The sensor information unit 88 is configured with settings for sensor ID unit 88-1, distance unit 88-2, execution mode unit 88-3, measurement count unit 88-4, temperature unit 88-5, battery voltage unit 88-6, and so on.

[0111] The sensor ID unit 88-1 stores identification information, including a sensor ID that identifies each liquid level sensor 2.

[0112] The distance unit 88-2 stores numerical information representing the distance D measured at each operating time ta and tb.

[0113] The execution mode unit 88-3 stores numerical information representing the short-range mode or long-range mode used to measure distance D. For example, the tens digit of the numerical information is "1" for short-range mode and "2" for long-range mode. The measurement count unit 88-4 stores the number of measurements used for distance measurement. The maximum number stored is "4". For example, "1-4" indicates that four measurements were successfully taken in short-range mode.

[0114] The temperature section 88-5 stores numerical information representing the temperature acquired by the temperature sensor 20.

[0115] The battery voltage unit 88-6 stores numerical information representing the battery voltage V acquired by the control unit 8.

[0116] The access recording unit 90 then records access information such as access information indicating that there was access from the management server 76, and access information such as the transmission of sensor information.

[0117] <Liquid level management information DB80> Figure 8 shows an example of a liquid level management information DB80. This liquid level management information DB80 stores information such as a date and time information unit 96, a sensor information unit 98, a tank ID unit 99, a customer ID unit 100, a tank location information unit 102, a remaining amount unit 104, an alert information unit 106, a delivery plan information unit 108, and a performance information unit 110.

[0118] The date and time information unit 96 stores time information, such as the date and time when sensor information was acquired from the relay unit 78 and calculations such as the remaining amount of kerosene 18 were performed.

[0119] The sensor information unit 98 is configured with settings for sensor ID unit 98-1, distance unit 98-2, execution mode unit 98-3, measurement count unit 98-4, temperature unit 98-5, battery voltage unit 98-6, and so on.

[0120] The sensor ID unit 98-1 stores identification information, including a sensor ID that identifies each liquid level sensor 2.

[0121] The distance unit 98-2 stores numerical information representing the distance D measured at each operating time ta and tb.

[0122] The execution mode unit 98-3 stores numerical information representing the short-range mode or long-range mode used to measure distance D. The stored contents are the same as those in the sensor information DB79.

[0123] The temperature section 98-5 stores numerical information representing the temperature acquired by the temperature sensor 20.

[0124] The battery voltage unit 98-6 stores numerical information representing the battery voltage V acquired by the control unit 8.

[0125] The tank ID section 99 stores identification information, including a tank ID that identifies each tank 16-1, 16-2, ..., 16-n.

[0126] The customer ID unit 100 stores customer ID information representing the customer to which each tank 16-1, 16-2, ..., 16-n belongs, and this customer ID is associated with the tank ID.

[0127] The tank location information unit 102 stores location information, such as GPS (Global Positioning System) information, representing the tank locations of tanks 16-1, 16-2, ..., 16-n, which are identified by their tank IDs.

[0128] The remaining amount section 104 stores numerical information representing the remaining amount of kerosene 18, calculated by the management server 76 using distance D. The remaining amount of kerosene 18 is an example of the remaining amount of liquid in the storage tank 16.

[0129] The alert information unit 106 compares the remaining amount of liquid in the tank with the required replenishment level and stores alert information generated when the remaining amount of kerosene 18 reaches or is approaching the required replenishment level.

[0130] The delivery plan information unit 108 stores calendar information representing the delivery date and delivery period, based on the delivery plan calculated by the management server 76.

[0131] The performance information unit 110 stores performance information such as whether a delivery plan has been executed or not, based on access to the relay unit 78 and whether delivery notifications have been executed or not from the delivery company terminal 84.

[0132] <Information processing in relay unit 78> Figure 9 shows the processing procedure for information processing in the relay unit 78. This processing procedure is an example of a liquid level management method or program of the present disclosure. In Figure 9, as in Figure 2, S is an example of a process, and the numbers assigned to S indicate an example of the process sequence, but the present disclosure is not limited to this process and process sequence.

[0133] This information processing includes acquiring sensor information (S301), updating the sensor information database (S302), determining access to the management server 76 (S303), and sending sensor information (S304). These processes are executed independently and asynchronously with the management server 76.

[0134] The relay unit 78 constantly determines whether it has received sensor information from each liquid level sensor 2-1, 2-2, ..., 2-n (S301), and is maintained in a standby state where sensor information can be acquired (NO in S301).

[0135] When the relay unit 78 acquires sensor information, it obtains the sensor ID from the sensor information (YES in S301), identifies the corresponding operating times ta and tb, and updates the sensor information in the sensor information DB 79 (S302). This ensures that all sensor information is stored in the relay unit 78 without any omissions.

[0136] The relay unit 78 is constantly accessed by the management server 76 at specific times to obtain sensor information (S303).

[0137] If the relay unit 78 receives an access request from the management server 76 (YES in S303), it sends sensor information in response to the management server 76's request (S304), provides it to the management server 76, and returns to S301. The relay unit 78 then repeats the process from S301 to S304.

[0138] <Information processing on management server 76> Figure 10 shows the processing procedure for information processing by the management server 76. This processing procedure is an example of a liquid level management method or program of the present disclosure. In Figure 10, as in Figure 9, S represents an example process, and the numbers assigned to S indicate an example of the process sequence; however, the present disclosure is not limited to this process and process sequence.

[0139] This information processing includes measuring the remaining amount of kerosene 18 (S401), acquiring sensor information (S402), associating sensor ID, tank ID, and customer ID (S403), calculating the remaining amount of kerosene 18 (S404), determining the remaining amount of kerosene 18 (S405), sending an alert (S406), determining the delivery date (S407), issuing delivery instructions (S408), making a delivery decision (S409), updating delivery records (S410), and notifying customer terminals 82-1, 82-2, ..., 82-n (S411).

[0140] The timing of the management server 76's access to the relay unit 78 is set, for example, to the timing of the remaining liquid level measurement for each liquid level sensor 2-1, 2-2, ..., 2-n. In this case, the management server 76 monitors for the arrival of the remaining liquid level measurement timing or the sending of an alert and determines the timing of the remaining liquid level measurement (S401). It waits until the remaining liquid level measurement timing arrives (NO in S401), but in emergencies such as when an alert is issued, it proceeds to the remaining liquid level determination (YES in S401).

[0141] When it is time to measure the remaining amount (YES in S401), the management server 76 accesses the relay unit 78 and obtains sensor information from the relay unit 78 (S402). The management server 76 obtains the sensor ID from the sensor information, associates this sensor ID with the tank ID and customer ID in the liquid level management information DB 80 (S403), and updates the sensor information in the liquid level management information DB 80.

[0142] The management server 76 uses the updated sensor information to calculate the remaining amount of kerosene 18 for each tank 16-1, 16-2, ..., 16-n identified by the customer ID (S404).

[0143] The management server 76 compares the remaining amount of kerosene 18 with the required replenishment level and determines whether the remaining amount of kerosene 18 in the corresponding tanks 16-1, 16-2, ..., 16-n is less than or equal to the required replenishment level (S405). If the remaining amount is greater than the required replenishment level (NO in S405), the server makes a determination for the next remaining amount.

[0144] If the remaining amount is less than or equal to the level requiring replenishment (YES in S405), the management server 76 generates alert information and sends out an alert (S406). The alert is sent to the delivery company terminal 84 and also to customer terminals 82-1, 82-2, ..., 82-n, identified by the tank ID.

[0145] Based on the comparison of remaining volume and the required replenishment level, the management server 76 determines the delivery dates for tanks 16-1, 16-2, ..., 16-n (S407) and issues delivery instructions to the delivery company terminal 84 (S408).

[0146] Upon receiving a delivery instruction at the delivery terminal 84, the delivery company responds to the instruction and notifies the management server 76 of the delivery result from the delivery terminal 84. The management server 76 determines whether delivery has been completed to the destination tanks 16-1, 16-2, ..., 16-n, which are the delivery destinations related to the delivery instruction (S409). If delivery is not completed (NO in S409), the management server 76 issues another delivery instruction to the delivery terminal 84 (S408) and repeats the same process until delivery is completed (S408, S409).

[0147] When the management server 76 has completed the delivery of kerosene 18 to the corresponding tanks 16-1, 16-2, ..., 16-n (YES in S409), it updates the delivery record (S410) and notifies the corresponding customer terminals 82-1, 82-2, ..., 82-n of the completion of delivery (S411).

[0148] <Information presentation> The display devices connected to the management server 76, including customer terminals 82-1, 82-2, ..., customer terminal 82-n, delivery company terminal 84, and others, may display mode information indicating short-range mode and long-range mode, or display battery voltage information.

[0149] <Effects of the second embodiment> According to this second embodiment, one of the following effects can be obtained. (1) Sensor information transmitted from each liquid level sensor 2-1, 2-2, ..., 2-n during an operating time of one or approximately two times per day is received by the relay unit 78, and the sensor information can be stored and updated in the relay unit 78, so that the latest sensor information can be continuously obtained.

[0150] (2) The processing on the relay unit 78 side, which acquires and updates sensor information, and the processing on the management server 76 side, which acquires sensor information from the relay unit 78 and calculates the remaining amount of kerosene 18, can be performed asynchronously and simultaneously, thereby improving the load balancing of information processing, speeding up each process, and the reliability of each process.

[0151] (3) Each liquid level sensor 2-1, 2-2, ..., 2-n can individually measure the remaining amount of kerosene 18, and even if the remaining amount in a particular tank 16 reaches the level requiring replenishment, the remaining amount in other tanks 16 can be measured and determined without being affected, thereby reducing the risk of running out of kerosene.

[0152] (4) By displaying mode information indicating the short-range mode and long-range mode on the display devices connected to the management server 76, such as customer terminals 82-1, 82-2, ..., customer terminal 82-n, delivery company terminal 84, and others, the measurement status of the liquid level sensor 2 can be monitored, thereby improving the reliability of the system.

[0153] (5) By displaying battery voltage information on customer terminals 82-1, 82-2, ..., customer terminal 82-n, delivery company terminal 84, and other display devices connected to the management server 76, it can be used as instruction information to instruct battery replacement, etc., thereby increasing the reliability of the system.

[0154] [Other embodiments] This disclosure includes the following embodiments. (1) The management server 76 and the relay unit 78 may be configured with different processing units such as computers, or they may be configured with a single computer.

[0155] (2) Multiple liquid level sensors 2 may be grouped together, and each group may be provided with a different relay unit 78 to relay the sensor information.

[0156] (3) The opening 40 provided in the tank 16 is a kerosene inlet, but this opening 40 does not have to be limited to a kerosene inlet, and an opening for installing a liquid level sensor 2 may be provided separately from the kerosene inlet.

[0157] (4) In the above embodiment, kerosene 18 was used as an example of the liquid container, but the liquid to be measured may also contain kerosene 18.

[0158] (5) In the above embodiment, kerosene 18 is used as an example of the liquid container, and the liquid level of this kerosene 18 is detected. However, the technology of this disclosure may be used to measure liquids containing kerosene 18, or to detect and manage the liquid level of liquids other than kerosene 18, such as water or wine, or to detect and manage the level of non-liquid containers.

[0159] As described above, the most preferred embodiments of this disclosure have been described. The technology of this disclosure is not limited to those described above. Various modifications and changes are possible for those skilled in the art based on the gist of the technology described in the claims or disclosed in the form for implementation. It goes without saying that such modifications and changes are within the scope of this disclosure. [Explanation of Symbols]

[0160] 2, 2-1, 2-2, ..., 2-n liquid level sensors 4. Ultrasonic transducer 6. Ultrasonic drive unit 8 Control Unit 10 Communications Department 12 Power supply section 14-1 Transmitting element 14-2 Receiving element 16, 16-1, 16-2, ..., 16-n tank 18 Kerosene 20 Temperature sensors 22 Starting section 24 Antennas 26 batteries 28 Boost Power Supply Unit 30 Tank body 34 Ground 36 Ceiling 38 Ventilation section 40 openings 42 Sensor housing 44 Protrusion 46 Cylinder part 48 Threaded section 50 Shielding member 52 Occlusion 54-1, 54-2 Plate support part 56-1, 56-2 Encirclement 58-1 First wiring board 58-2 Second wiring board 60-1, 60-2 screws 61 Adhesive layer 62 Fluorine resin layer 64-1, 64-2 Substrate support section 66-1, 66-2 Electrode section 68 Small diameter section 70 Diameter Large Part 72 O-ring installation section 74 Liquid Level Management System 76 Management Server 78 Relay Unit 79 Sensor Information Database 80 Liquid level management information database 82-1, 82-2, ..., 82-n Customer Terminals 84 Delivery Carrier Terminal 86 Date and Time Information Department 88 Sensor Information Unit 88-1 Sensor ID section 88-2 Distance section 88-3 Execution Mode Section 88-4 Measurement Count Section 88-5 Temperature section 88-6 Battery Voltage Section 90 Access Log Section 96 Date and Time Information Department 98 Sensor Information Unit 98-1 Sensor ID section 98-2 Distance section 98-3 Execution Mode Section 98-4 Measurement Count Section 98-5 Temperature section 98-6 Battery Voltage Section 99 Tank ID section 100 Customer ID Department 102 Tank position information unit 104 Remaining amount section 106 Alert Information Department 108 Delivery Planning Information Department 110 Performance Information Department

Claims

1. A sensor housing installed at the opening of the tank, An ultrasonic transmitting and receiving unit that transmits ultrasonic waves from the sensor housing toward the liquid surface of the liquid contained in the tank, and receives the reflected ultrasonic waves from the liquid surface in the sensor housing, A temperature sensor that detects the internal or external temperature of the sensor housing, Power supply unit including battery, A sensor information generation unit is set to operate at least twice a day or approximately twice a day, during which the ultrasonic transmitting and receiving unit is operated, the distance between the ultrasonic transmitting point and the liquid surface or the distance between the reflected wave receiving point and the liquid surface is measured, and sensor information is generated that includes tank information representing the tank, the distance, and one or more of the following: battery voltage, detected temperature, An information transmission unit that transmits the aforementioned sensor information, A liquid level sensor, including one.

2. Furthermore, the circuit board portion on which the ultrasonic transmitting and receiving unit is mounted, A surrounding portion that supports the substrate portion, separates it from the tank side, surrounds the ultrasonic element, and exposes the ultrasonic transmitting portion or ultrasonic receiving portion of the ultrasonic element to the tank side, A protective unit that protects the ultrasonic transmitting / receiving unit, the power supply unit, the sensor information generation unit, and the information transmission unit, A liquid level sensor according to claim 1, comprising:

3. Furthermore, the liquid level sensor according to claim 2 is further provided with a shielding membrane that surrounds the ultrasonic element and prevents the penetration of the contained liquid from the tank side to the sensor housing.

4. Furthermore, the ultrasonic transmitting and receiving unit includes a short-range mode for transmitting low-level ultrasonic waves and a long-range mode for transmitting high-level ultrasonic waves. The liquid level sensor according to claim 1, wherein the sensor information generation unit performs the short-range mode or the long-range mode and generates sensor information including the distance, the number of times the short-range mode or the long-range mode is performed and the performance information.

5. The liquid level sensor according to claim 1, wherein the ultrasonic transmitting and receiving unit includes an ultrasonic transducer having a transmitting element that transmits the ultrasonic waves toward the liquid surface and a receiving element that receives the reflected waves of the ultrasonic waves from the liquid surface, and the ultrasonic waves have a frequency of 300 kHz or close to that value, or exceeding 300 kHz.

6. Furthermore, the liquid level sensor according to claim 1, comprising a startup unit that receives a magnetic force from outside the sensor housing and activates the ultrasonic transmitting / receiving unit and the sensor information generation unit when this magnetic force is above a threshold.

7. The liquid level sensor according to claim 1, wherein the contained liquid is kerosene or a liquid containing kerosene.

8. Tank and, A liquid level sensor is configured to have at least two operating times per day or approximately per day, during which it transmits ultrasonic waves toward the liquid surface of the liquid contained in the tank, receives the reflected waves of the ultrasonic waves from the liquid surface, measures the distance between the ultrasonic transmission point or the reflected wave reception point and the liquid surface, and transmits sensor information including the distance along with one or more of the following: tank information representing the tank, battery voltage, and detected temperature. A sensor information storage unit that acquires and stores the sensor information transmitted by the liquid level sensor as needed, A liquid level management unit periodically or irregularly acquires the sensor information from the sensor information storage unit, and when the remaining liquid level in the tank reaches the level requiring replenishment, generates alert information and / or replenishment instruction information associated with the identification information of the tank and notifies the delivery company terminal. A liquid level management system, including...

9. Furthermore, the liquid level management unit relates tank information representing the tank to customer information representing the customer, and presents to the customer terminal any or more of the remaining amount of liquid in the tank, the replenishment instruction information including the delivery date and time of the liquid, and the replenishment result information, as described in claim 8.

10. A liquid level sensor installed at the opening of a tank is set to operate at least twice a day or approximately every day, and during each operating time, it transmits ultrasonic waves from the sensor housing toward the liquid surface of the liquid contained in the tank, receives the reflected waves of the ultrasonic waves from the liquid surface, measures the distance between the ultrasonic transmission point or the reflected wave reception point and the liquid surface, and transmits sensor information including the distance, tank information representing the tank, battery voltage, and detected temperature, or one or more of these. The sensor information storage unit performs the steps of acquiring and storing the sensor information from the liquid level sensor, The liquid level management unit periodically or irregularly acquires the sensor information from the sensor information storage unit, and when the remaining liquid level in the tank reaches the level requiring replenishment, it generates replenishment instruction information associated with the tank's identification information and notifies either or both the customer terminal and / or the delivery company terminal. A liquid level control method, including the following.

11. Furthermore, the liquid level management unit includes the step of relating tank information representing the tank with customer information representing the customer, and presenting to the customer terminal any or more of the remaining amount of liquid contained in the tank, the replenishment instruction information including the delivery date and time of the liquid contained, and the replenishment result information, according to claim 10.

12. Furthermore, the process includes installing the liquid level sensor which is activated when it receives a magnetic force exceeding a threshold, The process of activating the liquid level sensor by applying a magnetic force, A liquid level control method according to claim 10, including the method described in claim 10.

13. A program that is executed by a computer system, The system has a function that sets an operating time of at least two times per day or approximately per day, during which it transmits ultrasonic waves toward the liquid surface of the liquid contained in the tank, receives the reflected ultrasonic waves from the liquid surface, measures the distance between the ultrasonic transmission point or the reflected wave reception point and the liquid surface, and transmits sensor information including the distance along with one or more of the following: tank information representing the tank, battery voltage, and detected temperature. The function of acquiring the aforementioned sensor information and storing it in the sensor information storage unit, The system acquires the sensor information from the sensor information storage unit periodically or irregularly, and when the remaining liquid level in the tank reaches the level requiring replenishment, it generates replenishment instruction information associated with the tank's identification information and notifies the delivery company's terminal. A program to cause the aforementioned computer system to execute it.

14. Furthermore, the program according to claim 13, which causes the computer system to perform a function that associates tank information representing the tank with customer information representing the customer, and to display to the customer terminal any or more of the following: information on the remaining amount of liquid contained in the tank, replenishment instruction information including the delivery date and time of the liquid contained in the tank, and replenishment result information.

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