JP2018194363A - Water level sensor and water level observation device - Google Patents

Abstract

To provide a water level sensor with which it is possible to accurately detect a water level irrespective of whether flow velocity is high or low.SOLUTION: On the side face of a body pipe 100 are formed a water conveyance hole h1 and a water conveyance hole h2 on the upstream and downstream sides of flowing water, respectively. An inside pipe 110 is stored in the inside of the body pipe 100. A reed switch circuit board 10 is stored in the inside of an inside pipe 110. A plurality of reed switches 11 are mounted on the reed switch circuit board 10 while being arrayed in the height direction, with a prescribed space between the adjacent reed switches 11. A float 130 rises or falls in accordance with a water level in the body pipe 100. Magnets 141 and 142 establish electrical continuity to a reed switch 11 that corresponds to a position in the height direction of the float 130. The number of water conveyance holes h2 is larger than the number of water conveyance holes h1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water level sensor and a water level observation device that observes the water level using the water level sensor.

  In order to manage the river appropriately, it is necessary to observe the water level of the river. Patent Document 1 describes a conventional water level sensor.

Japanese Utility Model Publication 3-45148

  There is a need for a water level sensor that can accurately detect a water level even at a low flow velocity at which water flows at a low speed or at a high flow velocity at which water flows at a high speed. There is also a need for a water level observation device that can observe the water level in real time.

  An object of this invention is to provide the water level sensor which can detect a water level correctly irrespective of the height of flow velocity. An object of this invention is to provide the water level observation apparatus which can observe a water level in real time.

  The present invention provides a main body pipe having a plurality of water guide holes formed on a side surface, an inner pipe housed in the main body pipe, and a predetermined interval between adjacent reed switches housed in the inner pipe. And a reed switch board mounted with a plurality of reed switches arranged in the height direction, and a water level when water flows into or out of the main body pipe through the water conduction holes. In accordance with the float that rises or falls along the inner pipe, and a magnet that is attached to the float and that conducts a reed switch corresponding to a position in the height direction of the float among the plurality of reed switches; A measurement data generation unit that generates measurement data including water level data indicating the reed switch that has been conducted, and the main body pipe includes the plurality of guides. As the hole, the first number of first water guide holes are formed on the upstream side when the main body pipe is installed in running water, and the second number of the second number larger than the first number is formed on the downstream side. Provided is a water level sensor in which a water guide hole is formed.

  The present invention is installed in a river and wirelessly transmits measurement data obtained by measuring the water level of the river, and receives the measurement data transmitted from the water level sensor and transmits the measurement data wirelessly or by wire. A relay station, a data receiving unit for receiving the measurement data transmitted from the relay station, and processing the measurement data received by the data receiving unit to calculate the water level at which the water level sensor is installed The water level sensor includes a main body pipe having a plurality of water guide holes formed on a side surface, an inner pipe housed in the main body pipe, and an inner pipe housed in the inner pipe. A reed switch substrate mounted with a plurality of reed switches arranged in a height direction with a predetermined interval between the reed switches, and water is introduced through the water conduction holes. A float that rises or falls along the inner pipe according to the water level when flowing into or out of the body pipe, and the height of the float among the plurality of reed switches attached to the float A magnet for conducting a reed switch corresponding to the position of the direction, a measurement data generating unit for producing measurement data including water level data indicating the conducted reed switch, and a radio for transmitting the measurement data wirelessly, The main pipe is formed with a first number of first water conveyance holes on the upstream side of the river as the plurality of water conveyance holes, and a second number greater than the first number on the downstream side. Provided is a water level observation device in which two water guide holes are formed.

  According to the water level sensor of the present invention, the water level can be accurately detected regardless of the flow velocity. According to the water level observation device of the present invention, the water level can be observed in real time.

It is a perspective view which shows the water level sensor of one Embodiment. It is sectional drawing of the main body pipe in the water level sensor of one Embodiment. It is sectional drawing which shows the state which cut | disconnected the water level sensor of one Embodiment in the direction orthogonal to a height direction. It is a fragmentary perspective view which shows the state where the water level sensor of one Embodiment was submerged. It is sectional drawing which shows the structure of a reed switch. It is a circuit diagram showing how to connect a plurality of reed switches. It is a figure which shows the example of installation of a water level sensor. It is a block diagram which shows the water level observation apparatus of one Embodiment. It is a figure which shows the conduction | electrical_connection state of a reed switch. It is a figure which shows the relationship between the conduction | electrical_connection state of a reed switch, and a water level.

  Hereinafter, a water level sensor and a water level observation device according to an embodiment will be described with reference to the accompanying drawings. In this embodiment, a case where a water level sensor and a water level observation device are used to measure (observe) a river level or a water level when water overflows from a river is taken as an example, but an arbitrary water level can be measured.

  First, the structure of the water level sensor 1 of this embodiment is demonstrated using FIGS. In FIG. 1, the water level sensor 1 includes a cylindrical main body pipe 100. A lower lid 101 is attached to the lower end of the cylindrical main body pipe 100, and an upper lid 102 is attached to the upper end. In order to take out foreign matters such as sand flowing into the main body pipe 100, the lower lid 101 is preferably detachable from the main body pipe 100 as, for example, a screw-in type.

  The main body pipe 100 is formed of a plastic resin such as ABS (acrylonitrile, butadiene, styrene) resin. For example, the main body pipe 100 has a diameter of 5 to 7 cm and a length of about 60 cm.

  When the water level sensor 1 is installed in a river, it is installed so that the far side in FIG. 1 is the upstream side of the river (running water) and the near side is the downstream side. As shown in FIG. 2, a plurality of circular water guide holes h <b> 1 are formed on the upstream side of the side surface of the main body pipe 100, and a plurality of circular water guide holes h <b> 2 are formed on the downstream side. In FIG. 1, illustration of the water guide holes h1 and h2 is omitted.

  The plurality of water guide holes h <b> 1 and h <b> 2 are arranged in a line in the height direction of the main body pipe 100. The water guide hole h <b> 1 and the water guide hole h <b> 2 are formed at positions facing the radial direction of the main body pipe 100. The number of the downstream water guide holes h1 is smaller, and the number of the upstream water guide holes h2 is larger. In the present embodiment, there are two water guide holes h1 and five water guide holes h2, and the ratio of the number of water guide holes h1 to the number of water guide holes h2 is 2: 5. The diameter of the water guide holes h1 and h2 is, for example, 5 mm.

  The water guide holes h1 are provided at intervals of 24.5 cm, for example, and the water guide holes h2 are provided at intervals of 12.25 cm, for example. The uppermost water guide hole h2 is provided at a position higher than the position of the uppermost water guide hole h1. Since the lower end of the main body pipe 100 is blocked by the lower lid 101, water flows into the main body pipe 100 from the water guide holes h1 and h2. The water level in the main body pipe 100 becomes a height corresponding to the water level of a river or the like.

  However, if the lower cover 101 is not attached to the main body pipe 100, the water level in the main body pipe 100 may be lower than the actual water level due to a phenomenon called so-called weiring at a high flow rate. If the water level sensor 1 measures the water level while the water level in the main pipe 100 is lower than the actual water level, the actual water level will not be measured.

  As a result of verification by the present inventor, it is clear that when the number of the upstream water guide holes h1 is smaller than the number of the downstream water guide holes h2, the lowering of the water level in the main body pipe 100 due to damming can be reduced. became. Further, as a result of verification by the present inventors, it was found that the ratio of the number of water guide holes h1 to the number of water guide holes h2 is preferably 1: 2 to 1: 3. By making the number of the upstream water guide holes h1 smaller than the number of the downstream water guide holes h2, the water level in the main body pipe 100 can be made substantially the same as the actual water level. Therefore, according to the water level sensor 1 of the present embodiment, the actual water level can be measured.

  In FIG. 1, an inner pipe 110 made of, for example, stainless steel is disposed in the central portion of the main body pipe 100 in the radial direction. A lower end portion of the inner pipe 110 is closed and held by the lower lid 101. The upper end portion of the inner pipe 110 is open, passes through the upper lid 102 and the lower lid 121 of the upper pipe 120 described later, and projects into the upper pipe 120. Since the inner pipe 110 is closed at the lower end and is in close contact with the upper lid 102 and the lower lid 121 in the vicinity of the upper end, water does not enter the inner pipe 110.

  The inner pipe 110 houses a reed switch substrate 10 in which a plurality of reed switches 11 are arranged at intervals of 2 cm, for example. The reed switch 11 is disposed obliquely so that the longitudinal direction of the reed switch 11 has a predetermined angle with respect to the longitudinal direction (vertical direction) of the inner pipe 110.

  An upper pipe 120 having a lower lid 121 attached to the lower end and an upper lid 122 attached to the upper end is attached above the main body pipe 100. The upper pipe 120 is also made of plastic resin such as ABS resin. The upper pipe 120 has the same diameter as the main body pipe 100 and has a length of about 30 cm. The upper pipe 120 accommodates the radio device board 20 therein. A transparent housing 124 for housing the solar panel 24 is attached above the upper pipe 120.

  The solar panel 24 is connected to the radio device board 20 so as to supply power to the radio device board 20. The reed switch substrate 10 and the wireless device substrate 20 are connected so that the wireless device substrate 20 supplies power to each reed switch 11.

  A cylindrical float 130 is inserted into the inner pipe 110. The float 130 is hollow. As shown in FIG. 3, a base 140 made of, for example, an iron plate, to which magnets 141 and 142 are fixed, is screwed to the upper surface (upper end portion) of the float 130. Further, a balance weight 144 made of, for example, stainless steel is screwed to the upper surface of the float 130 so as to face the magnets 141 and 142 with the inner pipe 110 interposed therebetween.

  The magnet 141 is fixed to the base 140 so that the inner pipe 110 side is an N pole and the magnet 142 is an S pole on the inner pipe 110 side. An alternate long and short dash line indicates a line of magnetic force generated by the magnets 141 and 142. The positional relationship between the magnet 141 and the magnet 142 may be reversed. The entire base 140 and magnets 141 and 142 and the balance weight 144 have substantially the same weight.

  In a direction orthogonal to the direction connecting the water guide hole h1 and the water guide hole h2 on the inner peripheral surface of the main body pipe 100, for example, a pair of rails 103 that form a groove-shaped recess is attached. The pair of rails 103 is formed in a range from the lower end portion to the upper end portion of the main body pipe 100 at two opposing positions on the inner peripheral surface of the main body pipe 100. As shown in FIG. 3, the rail 103 is formed by attaching another part to the inner peripheral surface of the main body pipe 100, but the rail 103 may be formed by integral molding. In FIG. 1, the rail 103 is not shown.

  On the upper surface of the float 130, an anti-rotation plate 133 formed with a protrusion is screwed. When the protrusion of the rotation prevention plate 133 is engaged with the recess between the pair of rails 103, the float 130 rises or falls according to the water level in the main body pipe 100 without rotating. In FIG. 1, the position of the float 130 when the water level is relatively low is indicated by a solid line, and the position of the float 130 when the water level rises is indicated by a two-dot chain imaginary line.

  FIG. 4 shows a state in which the main body pipe 100 is completely submerged. Even when the main body pipe 100 is completely submerged, an air room AR in which air is accumulated is formed at the upper end of the main body pipe 100. Since the upper part of the float 130 above the waterline 104 is not submerged, sand iron in the water does not adhere to the magnets 141 and 142, and the float 130 does not malfunction due to the adhesion of sand iron.

  When the atmospheric pressure is P, the volume is V, n is the number of molecules of gas, R is a coefficient, and T is temperature, the equation of state of gas can be expressed as PV = nRT. In FIG. 4, the atmospheric pressure P0 is approximately 1 atmosphere. For example, the water pressure P1 is approximately 1 atm when submerged in 10 m. In this case, the internal pressure of the air room AR is (P0 + P1). From the gas equation of state, the volume of the air room AR is 50% of that when not submerged. That is, even if the main pipe 100 is completely submerged, an air room AR of approximately 50% of that when not submerged is formed, and the magnets 141 and 142 are maintained in a state where they are not submerged. The magnets 141 and 142 are located in the air room AR regardless of the water level.

  By the way, the main body pipe 100, the inner pipe 110, and the upper pipe 120 are not transparent, but in order to understand the internal structure, in FIG. 1 and FIG. 4, they are illustrated as if they were transparent.

  Water flows into or out of the main body pipe 100 through the water guide holes h1 and h2, and the water level in the main body pipe 100 changes. When the float 130 rises or falls along the inner pipe 110 according to the water level, the magnets 141 and 142 come close to any one of the plurality of reed switches 11.

  The reed switch 11 is configured as shown in FIG. The reed switch 11 has a configuration in which tips 1121 and 1131 of ferromagnetic leads 112 and 113 face each other with a gap inside a glass tube 111 filled with an inert gas. When the magnets 141 and 142 approach the reed switch 11, the N pole and the S pole are guided to the leads 112 and 113 by the magnetic lines of force from the N pole of the magnet 141 to the S pole of the magnet 142, and the tips 1121 and 1131 come into contact with each other. And conduct.

  As shown in FIG. 6, in the present embodiment, it is assumed that there are 24 reed switches 11, that is, reed switches 11 a to 11 k and 11 m to 11 y. The reed switch 11 a is mounted on the lowermost side on the reed switch substrate 10, and the reed switch 11 y is mounted on the uppermost side on the reed switch substrate 10.

  A voltage is applied to one of the leads 112 of the reed switches 11a to 11k and 11m to 11y from the radio board 20 via the common terminal tcom. The other leads 113 of the reed switches 11a to 11k and 11m to 11y are connected to mutually independent output terminals ta to tk and tm to ty. The output terminals ta to tk and tm to ty are connected to the radio device board 20.

  When the magnets 141 and 142 approach the reed switch 11 and the tips 1121 and 1131 of the leads 112 and 113 come into contact with each other and become conductive, the radio circuit board 20 from the output terminals ta to tk and tm to ty corresponding to the conductive reed switch 11. An electrical signal is supplied to. Of the reed switches 11a to 11k and 11m to 11y, the reed switch 11 at a position facing the magnets 141 and 142 of the float 130 whose position in the height direction changes according to the water level outputs an electrical signal. The electrical signal output from the reed switch 11 is a water level detection signal.

  The location where the water level sensor 1 configured as described above is installed will be described with reference to FIG. As shown in FIG. 7, the water level sensor 1 is attached to a fixed pile 210 that is an example of a river structure provided in the river 200. The water level sensor 1 installed in the river 200 measures the water level of the river 200. The water level sensor 1 is attached to, for example, a utility pole 410 closer to the house side (inside water side) than the dike 201. The water level sensor 1 installed on the house side of the river 200 measures the water level when the river 200 is flooded due to overflow or leakage, heavy rain, or inflow of water from other small rivers.

  The radio circuit board 20 of the water level sensor 1 at each location transmits measurement data indicating the measured water level by radio waves, as indicated by a one-dot chain line. A relay station 3 for receiving radio waves and relaying measurement data to a river water level monitoring office 4 to be described later is attached to a post 310 provided on the embankment 201. The place where the relay station 3 is installed is not limited to the embankment 201. The relay station 3 should just be installed in the arbitrary places within the distance which can communicate with the radio | wireless machine board | substrate 20. FIG.

  Next, the configuration and operation of the water level observation apparatus of the present embodiment will be described with reference to FIG. The water level observation device includes a water level sensor 1, a relay station 3, a data transmission / reception unit 41 and a data processing device 42 in the river water level monitoring office 4. The relay station 3 and the river water level monitoring office 4 are connected by wire or wireless. The relay station 3 and the river water level monitoring office 4 may be connected by an optical cable, or may be connected by a predetermined standard wireless line such as a mobile phone or a VSAT (Very Small Aperture Terminal).

  In FIG. 8, the wireless device board 20 in the water level sensor 1 includes a microcomputer 21, a wireless device 22, and a rechargeable battery 23. The rechargeable battery 23 may be provided outside the radio device board 20. The electric power from the solar panel 24 is supplied to the rechargeable battery 23, and the rechargeable battery 23 is charged. The solar panel 24 and the rechargeable battery 23 constitute a power supply unit of the water level sensor 1. The rechargeable battery 23 supplies power to the microcomputer 21, the wireless device 22, and the reed switch board 10. Instead of the solar panel 24 and the rechargeable battery 23, a precharged rechargeable battery or a dry battery may be used as the power supply unit.

  The microcomputer 21 includes a measurement data generation unit 211, a clock 212, and a storage unit 213. The measurement data generation unit 211 and the clock 212 can be functionally configured by a central processing unit (CPU) of the microcomputer 21, and the storage unit 213 can be configured by a storage device of the microcomputer 21.

  FIGS. 9A and 9B show examples of the reed switch 11 that conducts. 9A and 9B, the hatched reed switch 11 is a conducting reed switch 11. 9A and 9B, only the reed switches 11a to 11i are shown.

  As shown in FIG. 9A, when the magnets 141 and 142 are opposed to, for example, the reed switch 11e, only the reed switch 11e is turned on, and an electric signal is output only from the reed switch 11e. As shown in FIG. 9B, when the magnets 141 and 142 are opposed to, for example, an intermediate position between the reed switches 11e and 11f, the reed switches 11e and 11f are turned on, and electrical signals are output from the reed switches 11e and 11f. .

  As described above, one of the reed switches 11a to 11k and 11m to 11y is electrically connected to one reed switch 11 or two adjacent reed switches 11 according to the vertical position of the float 130 (magnets 141 and 142). A signal is output. Depending on conditions such as the strength of the magnetic force of the magnets 141 and 142 and the distance between the reed switch 11 and the magnets 141 and 142, the three adjacent reed switches 11 are turned on, and electrical signals are output from the three reed switches 11. There may be things.

  If the output value “1” is assigned to the reed switch 11 that conducts and outputs an electrical signal, and the output value “0” is assigned to the reed switch 11 that does not conduct and outputs an electrical signal, the measurement data generating unit 211 can generate water level data consisting of 24-bit digital values. The output value of the reed switch 11y is the most significant bit, and the output value of the reed switch 11a is the least significant bit.

  In the water level sensor 1 of the present embodiment, when the float 130 is positioned at the lowest position in the main body pipe 100, only the lowermost reed switch 11a is configured to conduct. When the float 130 is positioned at the uppermost position in the main body pipe 100, only the uppermost reed switch 11y is configured to conduct. That is, an electrical signal is output from any one of the reed switches 11 wherever the float 130 is positioned in the vertical direction in the main body pipe 100. In this way, it is possible to determine whether the water level sensor 1 is operating normally or not operating due to a failure or the like.

  As illustrated in FIG. 10, the measurement data generation unit 211 generates water level data from “000000000000000000000001” to “100000000000000000000000” according to the vertical position of the float 130. Time data from the clock 212 is supplied to the measurement data generation unit 211. The measurement data generation unit 211 generates measurement data including an identification code (ID) that uniquely identifies the water level sensor 1, time data, and water level data. The ID may be a MAC address.

  The storage unit 213 stores the measurement data at a predetermined time interval that is, for example, 10 minutes. The wireless device 22 transmits the measurement data stored in the storage unit 213 to the relay station 3. The water level sensor 1 transmits the water level measured at predetermined time intervals to the relay station 3. Observation of the water level at a predetermined time interval by the water level observation device is substantially real-time observation.

  The wireless device 22 may transmit measurement data to the relay station 3 by an event method, or respond to a data transmission request by the data processing device 42 in the river water level monitoring office 4 by a polling method. The measurement data may be transmitted to the relay station 3.

  In FIG. 8, the relay station 3 is illustrated so as to wirelessly communicate with one water level sensor 1, but as illustrated in FIG. 7, the relay station 3 may wirelessly communicate with a plurality of water level sensors 1. The measurement data includes an ID in order to identify each water level sensor 1.

  The wireless device 22 may be a wireless device of any standard. However, it is preferable to use a wireless device that conforms to the Wi-SUN standard using a frequency of 920 MHz band as the wireless device 22 because it saves power, has excellent communication quality, and has a relatively long communication distance.

  The relay station 3 includes a wireless device 31, a data transmission / reception unit 34, and a power supply unit 35. If the wireless device 22 is a wireless device that conforms to the Wi-SUN standard, the wireless device 31 is also a wireless device that conforms to the Wi-SUN standard. The power supply unit 35 supplies power to the wireless device 31 and the data transmission / reception unit 34. The power supply unit 35 may be a solar panel and a rechargeable battery, or may be a power supply unit that supplies power obtained from a commercial AC power supply to each unit.

  The data transmitting / receiving unit 34 transmits the measurement data received by the wireless device 31 from the wireless device 22 to the data transmitting / receiving unit 41 in the river water level monitoring office 4. The data transmitter / receiver 41 receives the measurement data transmitted by the data transmitter / receiver 34. The data processing device 42 processes the measurement data in order to calculate the water level of a river or the like. Since the measurement data includes an ID for identifying the water level sensor 1, the data processing device 42 can calculate the water level at the position where the water level sensor 1 is installed.

  The data processing device 42 converts the water level data “000000000000000000000001” to “100000000000000000000000” shown in FIG. 10 into detection values. In the present embodiment, as shown in FIG. 9B, the state in which two adjacent reed switches 11 are conducted is expressed by 0.5, so that the resolution of the water level that can be expressed by 24 reed switches 11 is 24. It can be set to 47, which is approximately twice as large as.

  As shown in FIG. 10, the water level data from “000000000000000000000001” to “100000000000000000000000” indicates detection values of 1.0 to 24.0. The data processing device 42 includes a table or conversion formula for converting a detection value (or water level data) of 1.0 to 24.0 into a water level. The data processing device 42 may display the water level calculated based on the measurement data (water level data) from each water level sensor 1 in the river water level monitoring office 4 or to a higher level monitoring office. And the measured data or the calculated water level may be transmitted.

  Thus, if the data processing device 42 is water level data in a state where only one reed switch 11 is conductive, the data processing device 42 calculates the water level based on the position in the height direction where the conductive reed switch 11 is provided. If the data processing device 42 is water level data in a state where two adjacent reed switches 11 are conductive, the data processing device 42 calculates the water level based on the center position in the height direction where the two conductive reed switches 11 are provided. To do.

  If the three adjacent reed switches 11 are conductive, the data processing device 42 may calculate the water level based on the position of the reed switch 11 located at the center in the height direction.

  According to the water level observation device of the present embodiment, the water level of a river or the like can be observed in real time unless the water level sensor 1 is submerged. When the water level sensor 1 (the upper pipe 120 that houses the wireless device 22) is submerged, the wireless device 22 cannot transmit measurement data to the relay station 3. The radio device 22 is preferably configured to transmit measurement data that could not be transmitted to the relay station 3 when the water level drops and the upper pipe 120 appears above the water level of a river or the like.

  Therefore, the storage unit 213 preferably has a capacity for storing measurement data of at least about half a day. If the polling method is used, the data processing device 42 requests transmission of measurement data to the microcomputer 21 via the relay station 3, so that the data processing device 42 is not transmitted due to submergence but is stored in the storage unit 213. Data can be acquired after submersion is resolved.

  If the polling method is not adopted, the data transmitting / receiving unit 41 may be a data receiving unit having only a data receiving function.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Water level sensor 3 Relay station 4 River water level monitoring office 10 Reed switch board 11, 11a-11k, 11m-11y Reed switch 20 Radio equipment board 22, 31 Radio equipment 23 Rechargeable battery 24 Solar panel 34 Data transmission / reception part 35 Power supply part 41 Data transmitter / receiver (data receiver)
42 Data Processing Device 100 Main Body Pipe 110 Inner Pipe 120 Upper Pipe 130 Float 141, 142 Magnet 211 Measurement Data Generation Unit 212 Clock 213 Storage Unit AR Air Room

Claims (8)

A main body pipe having a plurality of water conveyance holes formed on the side surface;
An inner pipe housed inside the body pipe;
A reed switch board that is housed inside the inner pipe and has a predetermined interval between adjacent reed switches and a plurality of reed switches mounted in a height direction; and
A float that rises or falls along the inner pipe according to the water level when water flows into or out of the main body pipe through the water guide hole,
A magnet attached to the float and conducting a reed switch corresponding to a position in the height direction of the float among the plurality of reed switches;
A measurement data generation unit that generates measurement data including water level data indicating the reed switch that has been conducted;
With
In the main body pipe, as the plurality of water guide holes, a first number of first water guide holes are formed on the upstream side when the main body pipe is installed in running water, and the first number is formed on the downstream side from the first number. A water level sensor characterized in that a second number of second water introduction holes are formed.   The water level sensor according to claim 1, wherein a ratio between the first number and the second number is 1: 2 to 1: 3.   The first water guide holes are arranged in the height direction of the main body pipe, and the second water guide holes are located at positions facing the first water guide holes in the radial direction in the height direction of the main body pipe. The water level sensor according to claim 1, wherein the water level sensor is arranged in an array.   The water level sensor according to any one of claims 1 to 3, further comprising a wireless device that wirelessly transmits the measurement data. A water level sensor that is installed in a river and wirelessly transmits measurement data obtained by measuring the water level of the river;
A relay station that receives the measurement data transmitted from the water level sensor and transmits the measurement data wirelessly or by wire,
A data receiving unit for receiving the measurement data transmitted from the relay station;
A data processing device that processes the measurement data received by the data receiving unit and calculates a water level at a position where the water level sensor is installed;
With
The water level sensor
A main body pipe having a plurality of water conveyance holes formed on the side surface;
An inner pipe housed inside the body pipe;
A reed switch board that is housed inside the inner pipe and has a predetermined interval between adjacent reed switches and a plurality of reed switches mounted in a height direction; and
A float that rises or falls along the inner pipe according to the water level when water flows into or out of the main body pipe through the water guide hole,
A magnet attached to the float and conducting a reed switch corresponding to a position in the height direction of the float among the plurality of reed switches;
A measurement data generation unit that generates measurement data including water level data indicating the reed switch that has been conducted;
A radio that wirelessly transmits the measurement data;

With
The main pipe is formed with a first number of first water conveyance holes on the upstream side of the river as the plurality of water conveyance holes, and a second number greater than the first number on the downstream side. A water level observation device characterized in that two water conveyance holes are formed.   If the water level data is water level data in which only one reed switch is conducted, the data processing device calculates the water level based on the position in the height direction where the conducted reed switch is provided, and is adjacent to the water level data. The water level is calculated based on the center position of the position in the height direction where the two reed switches that are conducted are provided if the water level data indicates that the two reed switches are conducted. The water level observation device described in 1.   The said magnet is attached to the upper end part of the said float, The said magnet is located in the air room formed inside the said main body pipe irrespective of a water level. Water level observation device.   The water level sensor is configured such that any one of a plurality of reed switches is conductive regardless of where the float is located in the vertical direction in the main body pipe. Item 8. The water level observation apparatus according to any one of Items 5 to 7.

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