JP2015075371A - Level detector and level monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a level detector and level monitoring system capable of detecting the water level or the like of a river in detail with a sensor without consuming electric power.SOLUTION: The level detector 10 includes: a support body 12; a plurality of environmental power generation elements 11 that are arranged on the support body 12 and convert non-electric energy latent in the environment into electric energy; and an electronic circuit unit 14 for detecting the position of the boundary of a detection object on the basis of the output from each of the plurality of environmental power generation elements 11. As the environmental power generation elements 11, thermoelectric conversion elements can be used, for example.

Description

  The present invention relates to a level detection device and a level monitoring system.

  In recent years, flood damage due to torrential rain and guerrilla heavy rain has occurred frequently, and countermeasures against flood damage have become more important than ever.

  Currently, as one of the countermeasures against flood damage, observation stations that collect information such as river level and rainfall are installed at intervals of about 10 km to 15 km along the river, and the information collected by those stations is collected at the center station. Systems have been developed that process and generate alarms as needed.

  In this type of system, polling (inquiry) is performed from the center station to the observation station at regular intervals (for example, every hour), and information is transmitted from the observation station to the center station accordingly. The center station checks whether there is an abnormal value in the information sent from the observation station, and if there is an abnormal value, shortens the polling interval and observes changes in water level and rainfall in detail.

Japanese Patent Laid-Open No. 2007-47878 JP 2010-170190 A

  It is an object of the present invention to provide a level detection device and a level monitoring system that can detect the position of a detection target boundary such as a river water level without supplying external power.

  According to one aspect of the disclosed technology, based on outputs from a support, a plurality of energy harvesting elements arranged on the support and converting non-electric energy into electrical energy, and the plurality of energy harvesting elements Thus, a level detection device having an electronic circuit unit for detecting the position of the boundary of the detection target is provided.

  According to another aspect of the disclosed technology, a plurality of level detection devices that detect a position of a detection target boundary, and a center station that collects information on the detection target boundary position from the plurality of level detection devices, The level detection device includes: a support; a plurality of energy harvesting elements that are arranged on the support and convert non-electric energy into electrical energy; and outputs from each of the plurality of energy harvesting elements. There is provided a level monitoring system having an electronic circuit unit for detecting a position of a boundary of the detection target based on the electronic circuit unit.

  According to the level detection device according to the one aspect, it is possible to detect the position of the boundary of the detection target without supplying external power by using a plurality of energy harvesting elements that convert non-electric energy into electric energy. Further, according to the level monitoring system according to the above aspect, since the level detection device that can detect the boundary position without supplying external power is used, many sensors can be used for level detection, and the water level of the river is detected in detail. it can.

FIG. 1 is a schematic diagram showing a level detection device (water level measurement device) according to the first embodiment. FIG. 2 is a cross-sectional view showing an example of a thermoelectric conversion element used as an energy harvesting element in the first embodiment. FIG. 3 is a block diagram showing the configuration of the electronic circuit unit. FIG. 4A is a schematic diagram illustrating an example in which the water level measuring device according to the first embodiment is installed in a river, and FIG. 4B is a diagram (image diagram) illustrating an output state of each energy harvesting element. FIG. 5 is a diagram illustrating an example of a processing flow when determining the water surface. 6A to 6C are diagrams showing the relationship between the position of the energy harvesting element and the electromotive force, the electromotive force difference, or the electromotive force variation. FIG. 7 is a block diagram of an electronic circuit unit when an auxiliary power supply is used. FIG. 8 is a schematic diagram illustrating a level detection apparatus according to the second embodiment. FIG. 9 is a schematic diagram showing a water level measuring apparatus according to the third embodiment. FIG. 10 is a block diagram illustrating a configuration of an electronic circuit unit of the water level measurement device according to the fourth embodiment. FIG. 11 is a diagram illustrating the trigger sensor. FIG. 12 is a flowchart for explaining the operation of the water level measurement device according to the fourth embodiment. FIG. 13 is a schematic diagram showing a level monitoring system according to the fifth embodiment. FIG. 14 is a schematic diagram showing a level monitoring system including a sluice gate opening and closing device. FIG. 15 is a schematic diagram showing a level monitoring system including a correction water level gauge. FIG. 16 is a schematic diagram showing a level detection device (powder level detection device) according to the sixth embodiment.

  Hereinafter, before describing the embodiment, a preliminary matter for facilitating understanding of the embodiment will be described.

  In the conventional system described above, since the installation intervals of observation stations are sparse as 10 km or more, it cannot be said that sufficient information on water level and rainfall can be acquired. Although it is conceivable to shorten the installation interval of the observation stations, this requires a great deal of cost.

  Also, because the polling interval is as long as about 1 hour, it is difficult to respond quickly to a sudden increase in the river due to heavy rain, etc. When an abnormal value is detected from information sent from the observation station, There was also a flood.

  In order to cope with such a problem, development of a self-supporting water level measuring apparatus is progressing. The self-supporting water level measurement device has a water level sensor, solar cell, communication device, and a support column to which they are attached. The function is specialized only for water level measurement, which simplifies the configuration and reduces costs. ing. Moreover, a solar cell is used as a power source. For this reason, the self-supporting water level measuring device can be flexibly installed at relatively short intervals along the river.

  By the way, in the self-supporting water level measuring device, a float type water level meter, a hydraulic pressure level meter, an ultrasonic water level meter, a crystal type water level meter or the like is used as a water level sensor. Increasing the number of sensors makes it possible to measure changes in water level in detail, improving reliability but increasing power consumption.

  Since the power source that supplies power to the water level sensor is used for a long period of time, maintenance such as removal of dirt and shielding is performed. In addition, a high-rise building is built around the installation of the self-supporting water level measurement device, and light applied to the solar cell panel may be shielded, which may prevent power generation.

  When a battery is used as a power source instead of a solar cell, the battery needs to be replaced every predetermined period.

  In the following embodiments, a level detection device and a level monitoring system that can detect the water level of a river in detail without supplying external power will be described.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a level detection apparatus according to the first embodiment. The present embodiment describes an example applied to a self-supporting water level measuring device that detects the water level of a river.

  As shown in FIG. 1, the self-supporting water level measurement device 10 according to the present embodiment has a columnar shape, and is installed so that a part of its longitudinal direction is immersed in a river 52. Further, the water level measuring device 10 includes a reference temperature setting unit 12, a plurality of energy harvesting elements 11, an electronic circuit unit 14, and a heat insulating member 13. The outer periphery of the water level measuring device 10 is covered with a heat insulating member 13, and only one surface of the energy harvesting element 11 is exposed from the heat insulating member 13.

  The reference temperature setting unit 12 is an elongated plate-like or columnar member. The reference temperature setting unit 12 is formed of a material having high thermal conductivity such as copper, and therefore, the temperature difference in the longitudinal direction is small and the whole can be regarded as substantially the same temperature. In the first embodiment, the reference temperature setting unit 12 supports a plurality of energy harvesting elements 11, an electronic circuit unit 14, and a heat insulating member 13.

  The portion of the reference temperature setting unit 12 that is not covered with the heat insulating member 13 is in contact with or buried in the riverbed 51 where the temperature changes little throughout the year.

  In addition, about the support functions, such as the some energy harvesting element 11 with which the reference temperature setting part 12 of 1st Embodiment is provided, the support body different from the reference temperature setting part 12 may bear.

  The environmental power generation elements 11 are arranged on one surface of the reference temperature setting unit 12 at a constant interval (for example, an interval of 5 cm to 10 cm) along the longitudinal direction of the reference temperature setting unit 12. The energy harvesting element 11 is an element that converts non-electric energy such as light, vibration, heat, or electromagnetic wave that is latent in the environment into electrical energy.

  As the environmental power generation element 11, a thermoelectric conversion element, a piezoelectric element, a solar cell, a vibration power generation element, or the like can be used. In the present embodiment, a thermoelectric conversion element is used as the energy harvesting element 11. Details of the thermoelectric conversion element will be described later.

  The electronic circuit unit 14 is disposed on the upper part of the water level measuring device 10 and is electrically connected to the energy harvesting element 11. The electronic circuit unit 14 is connected to the center station wirelessly or by wire, and transmits information on the water level detected by the energy harvesting element 11 to the center station. Details of the electronic circuit unit 14 will also be described later. The center station is an example of an external facility.

  The heat insulating member 13 protects the energy harvesting element 11, the reference temperature setting unit 12, and the electronic circuit unit 14 from water, corrosive gas, and the like, and prevents a rapid temperature change of the reference temperature setting unit 12. 12 serves to reduce the temperature difference in the longitudinal direction. For this reason, it is important that the heat insulating member 13 has good water resistance, low thermal conductivity and low electrical conductivity, and high physical and chemical stability. For example, acrylic, vinyl chloride, styrene foam, or the like can be used as the material of the heat insulating member 13.

  FIG. 2 is a cross-sectional view showing an example of a thermoelectric conversion element used as the energy harvesting element 11 in the present embodiment.

  As shown in FIG. 2, the thermoelectric conversion element 20 used in the present embodiment has a structure in which p-type thermoelectric structures 21a and n-type thermoelectric structures 21b are alternately arranged between a pair of heat transfer plates 24a and 24b. Have. The p-type thermoelectric structure 21a and the n-type thermoelectric structure 21b are electrically connected in series by electrodes 22 arranged on the heat transfer plates 24a and 24b side, respectively. A protective member 23 may be filled in the gap between the p-type thermoelectric structure 21a and the n-type thermoelectric structure 21b in order to protect the thermoelectric structures 21a and 21b from water, corrosive gas, and the like.

  In the thermoelectric conversion element 20 having such a structure, electric power corresponding to the temperature difference between the heat transfer plates 24a and 24b is generated. In the present embodiment, one of the heat transfer plates 24 a and 24 b is thermally connected to the reference temperature setting unit 12, and the other is exposed to the side surface of the water level measurement device 10 and comes into contact with water or the atmosphere.

  A commercial product (for example, manufactured by KELK or manufactured by Micropelt) can be used as the thermoelectric conversion element 20, but may be newly prepared.

  When newly produced, the diameters of the p-type thermoelectric structure 21a and the n-type thermoelectric structure 21b may be 5 μm to 100 μm, for example, and the height may be 50 μm to 500 μm, for example. The aspect ratio (ratio of diameter to height) of the p-type thermoelectric structure 21a and the n-type thermoelectric structure 21b may be 2 to 40, for example. Furthermore, the distance between adjacent p-type thermoelectric structures 21a and n-type thermoelectric structures 21b may be set to 5 μm to 100 μm, for example. One thermoelectric conversion element 20 includes, for example, 100 to 1000 pairs of p-type thermoelectric structures 21a and n-type thermoelectric structures 21b.

As the material of the thermoelectric structures 21a and 21b, telluride, oxide material, silicide, skutterudite, or the like can be used. For example, Bi _0.3 Sb _1.7 Te ₃ or the like can be used as the material of the p-type thermoelectric structure 21a, and Bi ₂ Te ₃ or the like can be used as the material of the n-type thermoelectric structure 21b.

  As the protective member 23, it is preferable to use a protective member having high insulation, low thermal conductivity, high mechanical strength and chemical stability. As the protection member 23, for example, glass or resin can be used.

  As the electrode 22, for example, a laminated film formed by sputtering or vapor deposition (a base film such as Ti or Cr, a diffusion prevention layer such as Pt, and a wiring layer such as Au or Cu), an inkjet method, or other printing methods. The formed Au or Ag film can be used. The heat transfer plates 24a and 24b are at least insulative on the surface, and are formed of a material having high thermal conductivity such as alumina or aluminum nitride.

  FIG. 3 is a block diagram illustrating a configuration of the electronic circuit unit 14.

  As shown in FIG. 3, the electronic circuit unit 14 includes a main control unit 25, a communication unit 26, a power supply control unit 27, and a storage element 28.

  As described above, in this embodiment, a thermoelectric conversion element is used as the energy harvesting element 11. One of the pair of heat transfer plates of the thermoelectric conversion element is in contact with the reference temperature setting unit 12, and the other is in contact with water flowing through the river 52 or the atmosphere. Therefore, the energy harvesting element 11 in contact with water generates electric power according to the temperature difference between the water and the reference temperature setting unit 12, and the energy harvesting element 11 in contact with the atmosphere is in the atmosphere and the reference temperature setting unit 12. Electric power is generated according to the temperature difference.

  The power supply control unit 27 includes a DC (direct current) -DC (direct current) converter, converts the electric power generated by the energy harvesting element 11 into a predetermined voltage, and accumulates it in the power storage element 28. As the storage element 28, for example, a secondary battery such as a lithium ion battery can be used.

  Further, the power supply control unit 27 supplies the electric power stored in the power storage element 28 as the driving power when the main control unit 25 and the communication unit 26 are driven.

  By the way, the temperature of the atmosphere and the temperature of the water flowing in the river 52 are often different. For example, the temperature of the atmosphere is higher than the water temperature in summer, and conversely lower than the water temperature in winter. That is, if the reference temperature setting unit 12 is set to a constant temperature, the electromotive force differs between the energy harvesting element 11 in contact with water and the energy harvesting element 11 in contact with the atmosphere. For this reason, the main control unit 25 can discriminate the energy harvesting element 11 in contact with water and the energy harvesting element 11 in contact with the atmosphere from the power output from each energy harvesting element 11. . And the main control part 25 determines the water level (position of the water surface) of the river 52 from the determination result.

  The main control unit 25 is connected to the center station 30 through the communication unit 26 and transmits information on the water level detected by the energy harvesting element 11 to the center station 30.

  FIG. 4A is a schematic diagram showing an example in which the water level measuring device 10 according to the present embodiment is installed in the river 52. FIG. 4B is a diagram (image diagram) showing the output state of each energy harvesting element with time on the horizontal axis and electromotive force (V) on the vertical axis. Here, it is assumed that it is used in summer when the temperature is higher than the water temperature.

  Here, in order to simplify the description, as shown in FIG. 4A, the water level measuring device 10 has eight energy harvesting elements 11a to 11h arranged at regular intervals in the vertical direction. To do. The energy harvesting elements 11a to 11d are located in the river 52 (underwater), the energy harvesting elements 11f to 11h are located in the atmosphere, and the energy harvesting element 11e is located near the water surface.

  Heat is transmitted to the reference temperature setting unit 12 from water or the air flowing through the river 52 via the energy harvesting elements 11a to 11h. Therefore, the temperature of the reference temperature setting unit 12 is a temperature between the temperature of water flowing through the river and the temperature of the atmosphere. The reference temperature setting unit 12 is covered with a heat insulating member 13 so as not to be affected by direct sunlight or the like as much as possible.

  For example, as shown in FIG. 4B, the electromotive force of the energy harvesting elements 11f to 11h located in the atmosphere is greatly different from that of the energy harvesting elements 11a to 11d located in the water.

  Moreover, since the energy harvesting element 11e located in the vicinity of the water surface is exposed to water or air due to the undulation of the water surface, the electromotive force of the energy harvesting element 11e varies greatly.

  As described above, the electromotive force and its change with time are greatly different between the energy harvesting elements 11a to 11d located in the water, the energy harvesting element 11e located near the water surface, and the energy harvesting elements 11f to 11g located in the atmosphere. Therefore, the main control unit 25 can determine the position (water level) of the water surface from the electromotive force of each of the energy harvesting elements 11a to 11h.

  For example, in the example illustrated in FIG. 4B, the electromotive forces of the energy harvesting elements 11f to 11g are larger than the electromotive forces of the energy harvesting elements 11a to 11e. Further, the electromotive force of the energy harvesting element 11e has a greater change with time than the other energy harvesting elements 11a to 11d and 11g to 11b. Therefore, the main control unit 25 can determine the position (water level) of the water surface from the electromotive force of each of the energy harvesting elements 11a to 11f.

  A flow chart for determining the water surface is shown in FIG. 5, and the relationship between the output value and the water surface is shown in FIG. Here, two types of methods are described: a method for detecting the water surface from the electromotive force difference ΔV between adjacent energy harvesting elements, and a method for detecting the water surface from the time variation (dV / dt) of the electromotive force between each energy harvesting element.

  FIG. 5 is the same as the method for detecting the maximum value from a certain array (a [m]). That is, an environmental power generation element that shows the maximum value of the electromotive force difference ΔV between adjacent energy generation elements or the time variation dV / dt of the electromotive force is detected, and the position of the energy generation element is determined to be substantially the position of the water surface.

  In FIG. 6, the horizontal axis indicates the positions of the energy harvesting elements 11a to 11h, and the vertical axis indicates the electromotive force (FIG. 6 (a)), the electromotive force difference (FIG. 6 (b)), or variations in the electromotive force (FIG. 6 ( It is a figure which takes c)) and shows those relationship.

  First, FIG. 6B shows that the electromotive force difference of the energy harvesting element 11f is the maximum. Thereby, it is determined that the water surface is near the energy harvesting element 11f. However, since the first energy harvesting element 11a has no comparison object, the value is set to zero. Moreover, when the time change (electromotive force variation dV / dt) of the electromotive force of the energy harvesting element in FIG. 6C is seen, the value of the energy harvesting element 11e is the maximum value. Therefore, it is determined that the water surface is near the energy harvesting element 11e.

  The water level detection by the two types of methods may have an error corresponding to one or two sensors, but is accurate enough to prepare for river flooding.

  As a more specific example, consider a case where a thermoelectric conversion element having an air temperature of 30 ° C., a water temperature of 25 ° C., a reference temperature setting unit temperature of 28 ° C., and an electromotive force of 0.14 V / K is used.

  At this time, the electromotive force of the energy harvesting elements 11a to 11d is about minus 0.4V, and the electromotive force of the energy harvesting elements 11f to 11g is about plus 0.3V.

  The electromotive force of the energy harvesting element 11e varies in the vicinity of 0V. Therefore, the water surface is between the energy harvesting element 11d and the energy harvesting element 11f having a large electromotive force difference, and can be determined to be in the vicinity of the energy harvesting element 11e having a large electromotive force change (dV / dt).

  As described above, in the present embodiment, since the environmental power generation element 11 (thermoelectric conversion element 20) that generates electric power due to a temperature difference is used as a sensor, the power consumption by the sensor is 0, and the water level measurement device 10 Many sensors can be mounted on the. Thereby, the water level of the river 52 can be detected in detail. On the other hand, even in winter when the temperature is lower than the water temperature, the water level can be detected by the same method although the sign of the electromotive force is reversed.

  Further, in the present embodiment, the electric power generated by the energy harvesting element 11 used as a sensor is stored in the power storage element 28 and used as driving power for the main control unit 25 and the communication unit 26, thereby reducing running costs and maintenance costs. Is done.

  In addition to the energy harvesting element 11, a solar battery 29 or other power source may be used in combination as an auxiliary power source as shown in FIG. In the example shown in FIG. 7, the power generated in the solar cell 29 can be boosted to a predetermined voltage by the power supply control unit 27 and stored in the power storage element 28. For example, when the power generation amount of the energy harvesting element 11 decreases, the driving power of the main control unit 25 and the communication unit 26 may be covered.

  Hereinafter, the result of trial calculation of the power generation amount of the energy harvesting element will be described.

  It is assumed that four thermoelectric conversion elements (KTGS066A00) manufactured by KELK are used as the environmental power generation element 11, and a wireless communication module (TEW-001) manufactured by TOCOS is used as the communication unit 26. Further, it is assumed that a DC-DC converter having a conversion efficiency of 30% is used for the power supply control unit 27.

In this case, the power after the four thermoelectric conversion elements 11 are connected in series and boosted by the DC-DC converter is about 30 μW / (K ² ). On the other hand, the power required for one transmission of information by the communication unit 26 is about 200 μWs.

  Therefore, when the temperature difference between one surface and the other surface of the thermoelectric conversion element is 1 ° C., the wireless communication module can transmit information at a rate of once every 7 seconds. That is, if the temperature difference between one surface and the other surface of at least four thermoelectric conversion elements is 1 ° C. or more, the power consumed by the wireless communication module can be covered.

(Second Embodiment)
FIG. 8 is a schematic diagram showing a level detection device (water level measurement device) according to the second embodiment. 8, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The water level measurement device 10a according to the present embodiment is installed by bringing the back surface (surface opposite to the surface where the environmental power generation element 11 is disposed) side of the reference temperature setting unit 12 into direct contact with the riverbank (soil) 53. The soil portion of the riverbank 53 has a small temperature change throughout the year deep in the ground, and can maintain a relatively large temperature difference from the temperature of the water flowing through the river 52 or the temperature of the atmosphere.

  The reference temperature setting unit 12 includes a structure such as a pile only in a portion that is in deep contact with the ground. As described above, since the temperature is uniform throughout the year deep in the ground, this structure contributes to maintaining the reference temperature setting unit 12 at a constant temperature. Moreover, the other part of the reference temperature setting part 12 is covered with the heat insulation member 13, and exchange of thermal energy with air | atmosphere or water is made as small as possible. For this reason, it is considered that the water level measurement device 10a according to the present embodiment is easier to detect the water level than the water level measurement device 10 installed at the center of the river 52 as shown in FIG.

(Third embodiment)
In the first embodiment, the case where a thermoelectric conversion element is used as the energy harvesting element 11 has been described. However, another energy generation element may be used as the energy harvesting element 11.

  FIG. 9 is a schematic diagram showing a water level measuring apparatus according to the third embodiment.

  The water level measuring device 10b according to the present embodiment has a power generation element (environmental power generation element) 16 having a water wheel and a power generator (not shown) that generates power by the power of the water wheel, along a longitudinal direction of the support column 15. It has a structure attached at intervals. The power generation element 16 generates electric power by rotating a water wheel connected to a water-based generator.

  In this water level measuring device 10b, it is possible to determine the position between the two power generating elements 16 that generate the largest power difference as the position of the water surface. The water level measuring device 10b includes an electronic circuit unit (see FIG. 3) similar to that of the first embodiment, accumulates the power generated by the power generation element 16 in the storage element, and drives the main control unit and the communication unit to drive power. Supply.

(Fourth embodiment)
In the first embodiment, the main controller 25 constantly monitors the power generation amount of each energy harvesting element 11. Therefore, it is conceivable that part of the electric power generated in each energy harvesting element 11 always flows directly to the main control unit 25 and the electric power accumulated in the power storage element 28 is reduced.

  In this embodiment, when there is no fear of flooding, only the amount of power generated by a specific energy harvesting element is monitored, and the power generated by other energy harvesting elements is stored in the energy storage element, thereby accumulating more power in the energy storage element. To do.

  FIG. 10 is a block diagram illustrating a configuration of an electronic circuit unit of the water level measurement device according to the fourth embodiment. Note that this embodiment is different from the first embodiment in that the configuration of the electronic circuit unit is different, and other configurations are basically the same as those of the first embodiment. Therefore, the description of the part which overlaps with 1st Embodiment is abbreviate | omitted.

  The electronic circuit unit 14 a of the water level measurement device according to the present embodiment includes a main control unit 25, a communication unit 26, a power supply control unit 27, a storage element 28, and a switching circuit unit 32.

  The main control unit 25 uses one of the energy harvesting elements 11 as a trigger sensor, and determines whether the position of the water surface is below the trigger sensor. The main control unit 25 controls the switching circuit unit 32 based on the determination result.

  As the trigger sensor, an energy harvesting element disposed at a position somewhat higher than the water level of the river 52 at normal times is used. Here, the energy harvesting element 11e shown in FIG. 11 is a trigger sensor.

  FIG. 12 is a flowchart for explaining the operation of the water level measuring apparatus according to this embodiment.

  First, in step S11, the main control unit 25 sets the switching circuit unit 32 to the normal mode. That is, the main control unit 25 controls the switching circuit unit 32 to connect only a part of the energy harvesting elements including the trigger sensor (the energy harvesting element 11e) to the main control unit 25, and is generated by other energy harvesting elements. All the electric power is stored in the power storage element 28 via the power supply control unit 27. Further, the main control unit 25 stops power supply to the communication unit 26.

  In the present embodiment, in the normal mode, among the energy harvesting elements, the energy harvesting element 11e that is a trigger sensor, the energy harvesting element 11b that is disposed in water, and the energy harvesting element 11h that is disposed in the atmosphere. Only one is connected to the main control unit 25 via the switching circuit unit 32. The other energy harvesting elements are connected to the energy storage element 28 via the power supply control unit 27, and the electric power generated by the other energy harvesting elements is stored in the energy storage element 28. For this reason, a large amount of electric power is stored in the storage element 28 in the normal mode.

  Next, it transfers to step S12 and the main control part 25 determines whether the water surface is lower than a trigger sensor from the electric power generation amount of the environmental power generation elements 11b, 11e, and 11h.

  For example, when the power generation amount of the energy harvesting element 11e (trigger sensor) is closer to the power generation amount of the energy harvesting element 11f disposed in the atmosphere than the power generation amount of the energy harvesting element 11b disposed in the water, the main control unit 25 It is determined that the water surface is below the position of the energy harvesting element 11e.

  On the other hand, when the power generation amount of the energy harvesting element 11e (trigger sensor) is closer to the power generation amount of the energy harvesting element 11b disposed in the water than the power generation amount of the energy harvesting element 11h disposed in the atmosphere, the main control unit 25 Determines that the water surface has reached the position of the energy harvesting element 11e.

  If it is determined in step S12 that the water surface is below the position of the trigger sensor (in the case of YES), the process returns from step S12 to step S11, and the normal mode is continued.

  When it determines with the water level having reached the position of the trigger sensor in step S12 (in the case of NO), it transfers to step S13.

  In step S13, the main control unit 25 controls the switching circuit unit 32 to shift to the emergency mode. In the emergency mode, all of the energy harvesting elements 11 a to 11 h are connected to the main control unit 25 and power is also supplied to the communication unit 26.

  The main control unit 25 detects the position of the water surface in detail based on the outputs of the energy harvesting elements 11a to 11h, and notifies the center station 30 of the occurrence of an emergency via the communication unit 26. Thereafter, the main control unit 25 transmits water level information to the center station 30 in response to polling from the center station 30.

  When the emergency mode is entered, the emergency mode is continued until it is determined in step S12 that the position of the water surface is below the position of the trigger sensor.

  As described above, in the present embodiment, when the position of the water surface is lower than the position of the trigger sensor and there is no risk of flooding, the communication unit 26 is put into a sleep state and operates in the normal mode. In the normal mode, the main control unit 25 monitors only the output of a specific energy harvesting element (in this embodiment, the energy harvesting elements 11b, 11e, and 11h), and the electric power generated by the other energy harvesting elements is stored in the energy storage element. 28 is accumulated. As a result, a large amount of electric power is stored in the power storage element 28.

  On the other hand, when the position of the water surface reaches the position of the trigger sensor and there is a risk of water damage, all the energy harvesting elements are connected to the main control unit 25 via the switching circuit unit 32, and the position of the water surface is detected in detail. Is done. The driving power is also supplied to the communication unit 26, and the main control unit 25 communicates with the center station 30 via the communication unit 26. Thereby, the center station 30 can know the change in the water level of the river in detail.

  In the present embodiment, when the position of the water surface is lower than the position of the trigger sensor, the normal mode is set, and the communication unit 26 is in a dormant state. However, the communication unit 26 may be driven at regular time intervals in the normal mode to notify the center station 30 that the water level measuring device 10 is operating normally.

(Fifth embodiment)
FIG. 13 is a schematic diagram showing a level monitoring system according to the fifth embodiment.

  As shown in FIG. 13, the level monitoring system according to the present embodiment includes a plurality of water level measurement devices 10 arranged along a river and a center station 30 that performs communication between the water level measurement devices 10. Have. In the present embodiment, the apparatus of the first embodiment (see FIG. 1) is used as the water level measuring device 10.

  The center station 30 performs polling at regular intervals, for example, and collects the water level information of the river from each water level measuring device 10. Further, when there is an abnormal value in the information sent from these water level measurement devices 10, the center station 30 collects more detailed water level information from each water level measurement device 10 by shortening the polling interval.

  Then, the center station 30 creates imaged data so that the water level at each position in the river can be understood from the information, and provides the data to the client 36 via the communication network 38. When the river level rises abnormally and may cause flooding, the center station 30 issues an alarm to the client 36.

  As described above, in the level monitoring system according to the present embodiment, the information on the water level at each position of the river collected by a large number of water level measuring devices 10 is collected in the center station 30. The center station 30 manages these pieces of information collectively, and issues a warning to the client 36 when there is a risk of flooding. This makes it possible to minimize damage caused by water damage.

  As shown in FIG. 14, the center station 30 and the sluice gate opening / closing device 39 may be communicatively connected to automatically open and close the sluice gate based on information on the river water level measured by the water level measuring device 10. .

  Further, as shown in FIG. 15, a correction water level meter 40 is installed at the same location as the specific water level measurement device 10, and the water level measured by the water level measurement device 10 and the water level measured by the correction water level meter 40 are center stations. You may make it compare by 30. As the correction water level meter 40, for example, an ultrasonic water level meter that can measure the water level with relatively high accuracy can be used.

  Thereby, the water level measured by the water level measuring device 10 can be corrected to improve the measurement accuracy, and the measurement reliability is improved. Further, when the water level measured by the water level measuring device 10 and the water level measured by the correction water level meter are greatly different, it can be determined that the water level measuring device 10 has failed.

(Sixth embodiment)
FIG. 16 is a schematic diagram illustrating a level detection apparatus according to the sixth embodiment. In the present embodiment, an example in which the present invention is applied to a powder level detection device that detects the level of powder stored in a container is described.

  As shown in FIG. 16, the powder level detection device 70 includes a support 71, a plurality of solar cells (environmental power generation elements) 72 arranged at regular intervals along the longitudinal direction of the support 71, and an external device ( An electronic circuit unit 73 that communicates with an external facility) is provided. The powder level detection device 70 is disposed in a container 75 in which powder 76 is charged, with the longitudinal direction being vertical.

  Each solar cell 72 generates electric power according to the amount of light received from the light source 77. Therefore, in the solar cell 72 arranged above the level of the powder 76, there is nothing to block the light emitted from the light source 77, so the amount of power generation is large. However, in the solar cell 72 arranged below the level of the powder 76, light is blocked by the powder 76, so the amount of power generation is small. The electronic circuit unit 73 detects the level of the powder 76 based on the power generation amount of each solar cell 72.

  Similar to the first embodiment, the electronic circuit unit 73 includes a main control unit, a communication unit, a power supply control unit, and a power storage element, and transmits information on the level of the powder 76 to an external device via the communication unit. .

  Also in the present embodiment, as in the first embodiment, the power consumption by the sensor is 0, and the powder level can be detected in detail using a large number of sensors. In addition, since the electronic circuit is driven using the electric power generated by the sensor (solar cell), there is an advantage that the running cost and the maintenance cost are low.

  The disclosed technology can also be applied to the detection of the amount of snow and the detection of landslides as uses other than the detection of river water level and powder level.

  The following additional notes are disclosed with respect to the above embodiments.

(Appendix 1) a support;
A plurality of energy harvesting elements arranged on the support and converting non-electric energy into electric energy;
An electronic circuit unit that detects a position of a boundary of a detection target based on outputs from each of the plurality of energy harvesting elements.

(Appendix 2) The plurality of energy harvesting elements are a plurality of thermoelectric conversion elements,
The level detection apparatus according to appendix 1, further comprising a heat insulating member that covers the support and has a lower thermal conductivity than the support.

  (Additional remark 3) The said electronic circuit part is equipped with the communication part which carries out communication connection to an external installation, The level detection apparatus of Additional remark 1 or 2 characterized by the above-mentioned.

  (Supplementary Note 4) The electronic circuit unit includes a main control unit that determines a boundary of the detection target based on an output from the energy harvesting element, a power storage element that accumulates power output from the energy harvesting element, The level detection apparatus according to any one of supplementary notes 1 to 3, further comprising: a power supply control unit configured to store electrodes generated by a plurality of energy harvesting elements in the storage element.

  (Supplementary note 5) The level detection device according to supplementary note 4, further comprising an auxiliary power source for supplying electric energy to the power storage element.

  (Supplementary note 6) The level detection device according to any one of supplementary notes 1 to 5, wherein the detection target is a liquid, and a part of the plurality of energy harvesting elements is in contact with the liquid.

  (Supplementary note 7) The level detection apparatus according to any one of supplementary notes 1 to 5, wherein the detection target is powder, and a part of the plurality of energy harvesting elements is in contact with the powder.

  (Supplementary note 8) The detection target is water flowing through a river, a part of the plurality of energy harvesting elements is in contact with water flowing through the river, and the electronic circuit unit is connected to each of the plurality of energy harvesting elements. 6. The level detection apparatus according to any one of appendices 1 to 5, wherein the level of the river is detected based on output electric power.

  (Additional remark 9) The said support body is arrange | positioned in contact with the riverbank of the said river, The level detection apparatus of Additional remark 8 characterized by the above-mentioned.

  (Additional remark 10) The said electronic circuit part uses a specific environmental power generation element of the said plurality of environmental power generation elements as a trigger sensor, and changes an operation mode by whether the water level of the said river is lower than the said trigger sensor. Item 10. The level detection apparatus according to appendix 8 or 9, which is characterized.

  (Supplementary note 11) The level detection device according to supplementary note 1, wherein the environmental power generation element is any one of a piezoelectric element, a solar cell, and a vibration power generation element.

(Appendix 12)
A plurality of level detection devices for detecting the position of the boundary of the detection target;
A center station that collects information on the position of the detection target boundary from the plurality of level detection devices,
The level detection device includes:
A support;
A plurality of energy harvesting elements arranged on the support to convert non-electric energy into electrical energy;
An electronic circuit unit that detects a position of a boundary of the detection target based on outputs from each of the plurality of energy harvesting elements.

(Supplementary note 13) The substance is water flowing through a river, and a part of the plurality of energy harvesting elements of the level detection device is in contact with water flowing through the river,
13. The level according to appendix 12, wherein the center station determines whether or not there is a risk of water damage from water level information acquired from the plurality of level detection devices, and generates a warning when determining that there is a risk of water damage. Monitoring system.

  (Supplementary note 14) The level monitoring system according to supplementary note 13, further comprising a correction water level meter, wherein the water level detected by the level detection device is corrected using the water level detected by the correction water level meter. .

  DESCRIPTION OF SYMBOLS 10, 10a, 10b ... Water level measurement apparatus (level detection apparatus), 11 ... Environmental power generation element, 12 ... Reference temperature setting part, 13 ... Thermal insulation member, 14 ... Electronic circuit part, 15 ... Support | pillar, 16 ... Power generation element, 20 ... Thermoelectric conversion element, 21a ... n-type thermoelectric structure, 21b ... p-type thermoelectric structure, 22 ... electrode, 23 ... protective member, 24a, 24b ... heat transfer plate, 25 ... main control unit, 26 ... communication unit, 27 ... Power control unit, 28 ... electric storage element, 29 ... solar cell, 30 ... center station, 32 ... switching circuit unit, 36 ... client, 38 ... communication network, 39 ... sluice open / close device, 40 ... correction water level meter, 52 ... river 53 ... River bank, 70 ... Powder level detection device, 71 ... Column, 72 ... Solar cell, 73 ... Electronic circuit part, 75 ... Container, 76 ... Powder, 77 ... Light source.

Claims (11)

A support;
A plurality of energy harvesting elements arranged on the support and converting non-electric energy into electric energy;
An electronic circuit unit that detects a position of a boundary of a detection target based on outputs from each of the plurality of energy harvesting elements. The plurality of energy harvesting elements are a plurality of thermoelectric conversion elements,
The level detection apparatus according to claim 1, further comprising a heat insulating member that covers the support and has a lower thermal conductivity than the support.   The level detection apparatus according to claim 1, wherein the electronic circuit unit includes a communication unit that communicates with an external facility.   The electronic circuit unit includes: a main control unit that determines a boundary of the detection target based on an output from the energy harvesting device; a power storage device that accumulates power output from the energy harvesting device; and the plurality of energy harvesting devices The level detection apparatus according to claim 1, further comprising: a power control unit that accumulates electric power generated by the element in the power storage element.   The level detection apparatus according to claim 4, further comprising an auxiliary power supply that supplies electric energy to the power storage element.   The detection target is water flowing through a river, a part of the plurality of energy harvesting elements is in contact with the water flowing through the river, and the electronic circuit unit outputs power output from each of the plurality of energy harvesting elements The level detection apparatus according to any one of claims 1 to 5, wherein the level of the river is detected on the basis of the level.   The level detection apparatus according to claim 6, wherein the support is disposed in contact with a riverbank of the river.   The electronic circuit unit uses a specific energy harvesting element of the plurality of energy harvesting elements as a trigger sensor, and switches an operation mode depending on whether or not a water level of the river is lower than the trigger sensor. The level detection device according to 6 or 7.   The level detection apparatus according to claim 1, wherein the environmental power generation element is any one of a piezoelectric element, a solar battery, and a vibration power generation element. A plurality of level detection devices for detecting the position of the boundary of the detection target;
A center station that collects information on the position of the detection target boundary from the plurality of level detection devices,
The level detection device includes:
A support;
A plurality of energy harvesting elements arranged on the support to convert non-electric energy into electrical energy;
An electronic circuit unit that detects a position of a boundary of the detection target based on outputs from each of the plurality of energy harvesting elements. The detection target is water flowing through a river, a part of the plurality of energy harvesting elements of the level detection device is in contact with water flowing through the river,
11. The center station according to claim 10, wherein the center station determines whether or not there is a risk of water damage from information on the water level acquired from the plurality of level detection devices, and generates an alarm when determining that there is a risk of water damage. Level monitoring system.

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