JP7105402B2 - Paddy water level measurement method - Google Patents

Description

The present invention relates to a field water supply and drainage system, and in particular, the control of the water level in paddy fields in a field affects the growth of cultivated crops. measurements are required. The present invention relates to a paddy water level measuring method using a water level gauge that can meet such demands.

For field water management, which is often done manually on site, remote control or automation is desired. It is also expected to save water through water management. In order to perform this water management appropriately, it is necessary to control both water supply and drainage to the field, and measurement of the water level, which is the basis of that control, is indispensable.
Furthermore, in paddy field cultivation, it is necessary to control the water level in the paddy field quickly, accurately, and finely in order to supply the cultivated crops with the amount of water required during the growth process of the cultivated crops. Therefore, water level measurement using a water level gauge is proposed.

Water level measurement using a water level gauge is common for water level measurement of stored water such as paddy fields, and various water level gauges and measuring methods thereof have been proposed.
For example, Patent Literature 1 discloses a level difference type water level gauge that is less susceptible to ambient temperature by providing a pipe that introduces atmospheric pressure in a liquid-tight manner to the low pressure side when the differential pressure gauge is used underwater. .
In detail, the internal pressure sensor is housed via the high-pressure side diaphragm and the low-pressure side diaphragm, and the differential pressure detection unit in which the liquid-tight space is provided facing the low-pressure side diaphragm, and the piping connected to the liquid-tight space. When the differential pressure detection part is installed in water, the water level gauge extends the piping above the water surface so that the pressure in the liquid tight space becomes atmospheric pressure, and the atmospheric pressure can be introduced.

In addition, Patent Document 2 discloses an inexpensive and easy-to-maintain water level gauge that can measure continuous changes in the water level even in an environment that is easy to get dirty like a paddy field. A cylindrical container that is closed, a water level / pressure conversion container (hereinafter referred to as "conversion container") that converts the water level into air pressure, and is installed at the top of this conversion container, It is characterized by having a pressure measuring means for measuring pressure as a differential pressure from the atmospheric pressure and a water level calculating means for calculating a water level from the differential pressure measured by the pressure measuring means. Since the water level is measured by converting the static pressure of air into a static pressure, the water level gauge does not allow the pressure measuring means to come into direct contact with water or mud.

Further, in Patent Document 3, by using two sensors, a pressure sensor for water pressure measurement and an atmospheric pressure sensor, a general-purpose electric wire having a simple configuration and a thin resin tube covering the outer side of the general-purpose electric wire A simple cable can be used, the workability is excellent, the cost is superior, and a predetermined water level can be accurately measured.

The disclosed water level gauge consists of a water level gauge body connected to one end of a cable and capable of being thrown into water, and a water level gauge body provided at the bottom of the water level gauge body for sealing gas such as air or nitrogen gas into a closed space. A differential pressure measurement unit (water pressure measurement sensor) that measures the differential pressure between the reference pressure and the water pressure due to the enclosed fluid obtained by enclosing in the water level gauge, an atmospheric pressure sensor provided separately from the water level gauge body, and a differential pressure It is equipped with an output unit that obtains the differential pressure between the differential pressure measured by the measuring unit and the atmospheric pressure detected by the atmospheric pressure sensor, converts the differential pressure into an electrical value, and outputs it. A general-purpose electric wire in which the outer periphery of the conductor is coated with a resin layer having corrosion resistance, weather resistance, and electrical insulation may be used alone for the cable that can be thrown into the cable, and a thin resin tube may be used for the electric wire. It is a water level gauge having a feature that may be fitted on the outside.

In addition, Patent Document 4 discloses a hydraulic water level gauge that improves measurement accuracy by eliminating errors that could not be corrected with conventional water level gauges that added water density correction due to changes in water temperature. . In detail, the water pressure type water level gauge detects the water level by measuring the pressure difference between the water pressure at a predetermined position in the water and the atmospheric pressure, and correcting the water temperature based on the water temperature value. Equipped with an air column correction circuit, and a turbidity sensor that corrects changes in water density due to turbidity based on the detected value of the turbidity sensor. In addition, it is a hydraulic water level gauge to which air column correction based on altitude value is added, or a hydraulic water level gauge to which air column correction and correction for changes in water density are added.

However, in the water level gauge and its measurement method disclosed in Patent Document 1, when a differential pressure detection unit having a liquid-tight space is installed in water, the pipe is placed above the water surface so that the pressure in the liquid-tight space becomes atmospheric pressure. By extending this, it is possible to introduce atmospheric pressure, but the influence of atmospheric pressure fluctuations in the liquid-tight space due to the piping that introduces the atmospheric pressure into the liquid-tight space cannot be eliminated from the measurement data. Accuracy and responsiveness are prone to problems.

On the other hand, in the water level gauge disclosed in Patent Document 2, due to its structure, it is difficult to accurately measure the water level unless water enters the container, and there is a problem in the validity of the measurement data when the water level is low. . There is also the problem of being susceptible to temperature changes in the air confined within the conversion vessel.

In addition, the water level gauge disclosed in Patent Document 3 is structurally equipped with two pressure sensors, one for measuring water pressure and one for measuring atmospheric pressure. When the water level of many places must be measured at the same time, the cost related to the water level gauge cannot be ignored. There are problems in handling such as failure frequency.

Furthermore, the water level gauge disclosed in Patent Document 4 adopts a water level measurement method in which air column correction and water density change correction based on altitude values are added, and is a hydraulic water level gauge with excellent responsiveness and measurement accuracy. However, in the method of measuring the water level with a plurality of water level gauges like in a field, each device by providing a device for correcting the air column correction and the density change of water similarly to the water level gauge of Patent Document 3 However, there are problems such as increased maintenance complexity, frequent failures, and high water level gauge costs.

JP 2003-004504 A JP-A-09-292272 JP-A-09-026348 JP-A-11-014429

In view of the above situation, the present invention proposes a simple and low-cost water level gauge that measures and controls the water level of paddy fields quickly and accurately in real time. A paddy water level measurement system for measuring water level data for control is provided.

A first invention of the present invention is a paddy field water level measuring method for measuring the water level of water stored in a field for controlling the water supply and drainage to a field surrounded by banks, wherein the water level measurement of the water stored in the field is performed. , is performed by a water level gauge installed in the field, the water level gauge is composed of a water level measurement unit, a signal processing unit, and a housing that houses the measurement unit, and the water level measurement unit is equipped with a diaphragm having an opening Differential pressure It consists of a measurement pressure sensor and a signal cable that transmits the measured value measured by the sensor to the signal processing unit, and the housing is a hollow housing that houses the sensor in a watertight structure at one end, and the air opening is in the hollow housing. On the other end side, when the water level gauge for paddy field is installed in the paddy field, it is provided so that the air vent faces the direction of the surface of the paddy field or a horizontal direction perpendicular to the direction of the surface of the paddy field, and a signal processing unit is provided. , equipped with a pressure-water level conversion device and a water level data transfer device, the water level gauge is installed in the field so that the air opening port of the water level gauge is located at a position higher than the height of the bank , It is installed at a position where power can be supplied from a water supply device that controls water supply to the field , and the hollow housing adopts an S-shaped form, and the end side provided with the differential pressure measurement pressure sensor is the paddy field water. The paddy water level measuring method is characterized in that the paddy field water level gauge is installed so as to be grounded or parallel to the ground surface of the paddy field when the level gauge is installed in the paddy field.

A second aspect of the present invention is a paddy water level measuring method in which the size of the opening to the atmosphere is equal to or larger than the size of the opening of the diaphragm.

A third aspect of the present invention is a signal cable outlet for drawing out the signal cable from the inside of the hollow casing to the outside on the other end side of the hollow casing provided with the air release port in the first or second invention. A paddy water level measurement method comprising

In a fourth invention of the present invention, the water level measuring section of the water level gauge in the first to third inventions has a temperature sensor, the signal processing section has a water temperature detection device, and the water level is calculated by compensating for changes in water pressure caused by water temperature fluctuations. It is a paddy water level measurement method to be measured.

A fifth invention of the present invention is a paddy water level measuring method according to the first to fourth inventions, wherein the hollow housing of the water level gauge is made of resin, and the signal processing unit is installed in the hollow housing.

A sixth invention of the present invention is a paddy water level measuring method according to the first to fifth inventions, wherein the water level gauge is a self-supporting water level gauge equipped with a self-supporting member.

The seventh aspect of the present invention is that the installation of the water level gauge in the field in the first to sixth inventions is performed at a position where power can be supplied from a water supply and drainage device for controlling water supply and drainage to the field, in the vicinity of the bank and in the field. It is a paddy water level measuring method for measuring the water level of water stored in a field.

The eighth invention of the present invention is the installation of the water level gauge in the field in the seventh invention, which is arranged along the water flow path that appears when water is supplied and drained in the field, so that the water level of the water in the field can be measured. This is the paddy water level measurement method.

According to the present invention, by using a paddy field water level gauge that is easy to handle as a paddy field water level gauge, excellent in responsiveness and data accuracy, and inexpensive in terms of cost, it is possible to measure a paddy field in a field, especially a whole paddy field. One-point or multi-point water level measurement of the stored water stretched in the field and control based on the measurement data can be realized quickly and accurately in real time, and it is industrially remarkable for achieving good growth of cultivated crops. It is effective.

BRIEF DESCRIPTION OF THE DRAWINGS It is an illustration figure which shows an example of the Example of the water level gauge used by this invention. 1 is a schematic cross-sectional view showing a schematic structure of a pressure sensor for measuring differential pressure; FIG. It is an illustration figure which shows the other example of the Example of the water level gauge used by this invention. It is an illustration figure which shows the other example of the Example of the water level gauge used by this invention. It is an illustration figure which shows the other example of the Example of the water level gauge used by this invention. It is an illustration figure which shows the form at the time of paddy field installation of the water level gauge used by this invention. It is an illustration figure which shows the other example of the Example of the water level gauge used by this invention. It is an illustration figure which shows the other example of the Example of the water level gauge used by this invention. It is an illustration figure which shows the other example of the Example of the water level gauge used by this invention. 1 is an illustrative view showing an embodiment of a water level gauge with water temperature compensation for use in the present invention; FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along the line aa, showing an example of an installation state of a paddy field water level gauge in a paddy field water level measuring method according to the present invention. It is an explanatory view of the paddy water level measuring method according to the present invention, and is a view showing the feature of installing the paddy water level gauge in the paddy field. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a paddy water level measuring method according to the present invention, showing feature 2 of installation of a paddy water level gauge in a paddy field; It is a diagram.

The paddy water level measuring method of the present invention will be described below with reference to FIGS. 1 to 13. FIG.
In the present invention, a highly responsive water level gauge that accurately measures the water level of the water in the paddy field is indispensable.

[Water level gauge]
1 and 2 show an outline of a paddy field water level gauge used in the present invention, and FIGS. 3 to 6 show other embodiments.

1 and 3 to 10 are schematic diagrams of the water level gauge, FIG. 2 is a schematic structural diagram showing the schematic structure of a differential pressure measuring pressure sensor used in the water level gauge, 10, 10a to 10h are water level gauges for paddy fields, 1 is a differential pressure measuring pressure sensor, 1a is a sensor housing, 1b is a sensor atmospheric pressure port, 1c is a sealed liquid, 1d is a sensor water pressure port, 2 is a diaphragm, 2a is a diaphragm opening, 3 is a hollow housing portion, 3a 3b is a signal cable outlet, 4 is a signal cable, 5 and 5a are filters, 6 is a temperature sensor, 30 is an air release port (integrated type), 100 is a pressure-water level converter, and 101 is water level data. Transfer device, 102 is a water temperature detection device, φ _A is the size of the opening to the atmosphere, φ _D is the size of the diaphragm opening, φ ₁ is the size of the sensor water pressure port, SC is the sensor element, the black arrow is the atmospheric pressure, White arrows indicate water pressure.
The air vent 3a faces the ground as shown in FIG. Or, as shown in FIG. 3, it can be mounted either horizontally or laterally with respect to the ground. On the other hand, the signal cable outlet 3b is oriented either toward the ground as shown in FIGS. 1 and 3, or horizontally horizontally with respect to the ground as shown in FIG. Install. Further, as shown in FIG. 6, since the soil of the paddy field is permeable, even if the sensor part is slightly buried in the ground surface, the underground water level is transmitted as water pressure, so that there is no problem.

The structural features of the water level gauge for paddy fields used in the present invention are shown in FIG. will be described below.
The water level gauge according to the present invention includes a water level measuring unit equipped with a differential pressure measuring pressure sensor that measures at least the differential pressure between the water pressure and the atmospheric pressure, and the measurement data obtained by the sensor as a "pressure-water level converter", "water level data It consists of a signal processing unit that transmits to the outside via a transfer device and a hollow housing that houses them.

The paddy water level gauge 10 has a diaphragm (see also FIG. 2, reference numeral 2) having an opening (see FIG. 2, reference numeral 2a) equal to or larger than the size of the sensor water pressure port. A differential pressure measuring pressure sensor 1 that can measure the pressure difference from the pressure (water pressure) from the measurement object (reserved water), and the sensor 1 is housed in a watertight structure at one end (A side), and at the other end (B side) Obstacles such as water, humidity, mud, animals and plants inside the hollow housing part 3 equipped with the air release port 3a and the signal cable outlet 3b for pulling out the signal cable 4 that transmits the measurement signal from the sensor 1, and the water level gauge It is composed of a filter 5 for preventing the intrusion of objects.

Further, as a major feature, the size φ _A of the air opening port 3a and the size φ _D of the opening of the diaphragm opening 2a of the pressure sensor 1 (see FIG. 2) satisfy φ _A /φ _D ≧1. 0 relationship.

2 is a schematic cross-sectional view of the schematic structure of the differential pressure measuring pressure sensor 1. 1 is a differential pressure measuring pressure sensor, 1a is a sensor housing, 1b is a sensor atmospheric pressure port, 1c is a silicon oil, fluorine oil, or the like. 1d is a sensor hydraulic port, 2 is a diaphragm, and 2a is a diaphragm opening, which indicates the contact effective range of the diaphragm surface on the side that contacts the object to be measured (retained water). In some cases, the diaphragm opening 2a is also filled with a liquid to protect the sensor. SC is the sensor element, φ _D is the size of the diaphragm opening, and indicates the scale of the previous contact effective range. It is indicated by the axial length or the area, and in the case of an asymmetrical shape, the area is applied. This scale of "size" is also applied to the size of the air opening port 3a, the size of the hollow housing portion 3, and the size of the sensor water pressure port 1d.

The water level gauges 10, 10a to _10h for paddy fields having the structures shown in FIGS. 1, the relationship φ _A /φ _D ≧1.0 with respect to the size φ _D of the opening 2 a of the diaphragm 2 through which water pressure is introduced, that is, the size of the opening 2 a of the diaphragm 2 If the opening is larger than the size, the responsiveness to the atmospheric pressure will be improved, and the synchronism between the water pressure measurement and the atmospheric pressure measurement can be improved when measuring the differential pressure to determine the water level of the paddy field. , and as a result, it has the effect of reducing the error in the differential pressure measurement. It also has the function of increasing the accuracy of real-time measurement.

The above relationship "φ _A /φ _D ≧1.0" means that the size of the opening 3a to the atmosphere is equal to or larger than the size of the opening 2a of the diaphragm 2. If this value is smaller than 1.0, , the transmission force of atmospheric pressure fluctuations to the diaphragm 2, that is, the responsiveness is reduced, but it shows a good effect against disturbance factors such as strong wind, heavy rain, and garbage clogging the opening. It is recommended to select a water level gauge with an appropriate opening depending on the environment where the water level is installed. The upper limit is desirably less than the ratio between the size of the hollow housing portion 3 and the size of the diaphragm opening 2a.

Here, when the water level rises or falls by variously changing the relationship of "φ _A /φ _D ", the time required for the water level gauge to indicate the phenomenon, that is, the response time, as a result of investigation, Table 1 shows the degree of influence of the "φ _A /φ _D " relationship on the response time when the water level is raised by 10 cm and when the water level is lowered. The test conditions were performed by changing only the size of the opening to the atmosphere.

Furthermore, the size φ _A of the atmospheric pressure release port 3a and the size φ ₁ of the sensor water pressure port 1d of the differential pressure measurement pressure sensor 1 may have a relationship of "φ _A /φ ₁ ≥ 1.0". This contributes to differential pressure measurement accuracy.

It also helps prevent dew condensation caused by a temperature difference caused by the positional relationship between the atmosphere opening port 3a and the pressure sensor 1. FIG. Furthermore, since the influence of pressure leaking from the inside of the device 100 or 101 can be eliminated via the signal cable 4, accurate measurement is possible.
In this way, the paddy water level gauge according to the present invention was invented as a result of taking into account mud, plant groups, paddy water level, etc. peculiar to paddy fields. It is a water level gauge that can be easily installed and removed, as well as the accuracy of water level measurement in paddy fields. The details of the paddy water level gauge will be further described below with reference to the drawings.

Another embodiment of the paddy water level gauge used in the present invention, indicated by numerals 10a-10h in FIGS. 3-10, will now be described.
3 to 5 show examples in which the arrangement of the air release port 3a and the signal cable outlet 3b is different from that of the water level gauge 10 shown in FIG.
In the water level gauge 10a of FIG. 3, the direction of the air opening port 3a is different from that of the water level gauge 10 of FIG. 1, and the air opening port is opened in the horizontal direction.
In the water level gauge 10b of FIG. 4, the cable opening 3b is horizontally opened.
In the water level gauge 10c of FIG. 5, the cable opening 3b is opened directly above the sensor 1a.

The paddy field water level gauge 10d shown in FIG. 6 is an illustrative view showing the configuration of the water level gauge shown in FIG. 1 when it is arranged in the paddy field. 9, the water level gauge is self-supporting in the paddy field, provided with a disk-shaped or square-shaped self-supporting support 8 that plays the role of a float so that the water level gauge does not sink from the paddy surface, and a water measurement port 7a is provided at the top of the arrow 9. form. The sensor 1 is slightly buried in the ground, but since the soil of the paddy field is permeable, even if the sensor 1 is slightly buried in the ground from the ground surface, the groundwater level is transmitted as water pressure. It does not pose a problem for water level measurement.

FIG. 7 is an illustrative view showing a paddy field water level gauge 10e provided with an integrated air release port 30 in which both the air release port and the signal cable outlet are integrated.
The integrated air vent 30 of this type aims at both the extraction of the signal cable and the improvement of the responsiveness to the atmospheric pressure, and also prevents foreign objects such as water, mud, animals and plants from entering the inside of the water level gauge (inside the hollow housing). A filter 5a is provided for air permeability, and it is desirable that this filter 5a is further air permeable.

FIG. 8 shows a water level gauge similar in type to the paddy water gauge of FIG. The water level gauge 10f for the paddy field arranged inside the part 3 includes the "pressure-water level converter 101", and has the advantage of being able to obtain a more compact water level gauge.

FIG. 9 shows a paddy field water level gauge 10g that is used by replacing the hollow casing 3 with a hollow flexible tube or a bellows tube and installing it in an inverted S shape as shown in FIG.
Using a hollow flexible tube or a bellows tube in this manner has the advantage that a self-supporting water level gauge can be obtained without preparing a separate self-supporting jig.

FIG. 10 shows a paddy field in which a temperature sensor 6 for detecting water temperature for compensating for fluctuations in water pressure due to water temperature during differential pressure measurement is attached to the paddy field water gauge 10 of FIG. It is an illustration figure which shows 10 h of water level gauges.
The temperature data measured by the temperature sensor 6 installed close to the differential pressure measuring pressure sensor 1 is sent to the water temperature detection device 102 and transmitted from the water level data transfer device 101 to the outside.

In the differential pressure measuring pressure sensor 1 used in this type of paddy water level gauge 10h, when the sensor housing 1a is made of a material with good thermal conductivity, the water temperature is transmitted to the temperature sensor 6 in the water level gauge. It is possible to play a role and improve the responsiveness of temperature measurement. Metal is preferable as the material, and aluminum or stainless steel is preferable in consideration of durability. In addition, since the temperature of the sensor housing and the water temperature become almost constant over time, this temperature sensor has the advantage of being able to measure the water temperature through the sensor housing. In this method, although there is a time difference in the constant temperature, it does not matter even if the sensor housing is made of resin.

Next, an example of how to use the water level gauge for paddy fields according to the present invention will be shown below.
FIG. 11 shows an example of the installation state of the water level gauge for paddy fields according to the present invention, where (a) is a plan view and (b) a sectional view taken along the line aa.
A ridge 22 having a water supply facility 20 for supplying water from a main waterway 25 into a field 23, and a drainage facility 21 having a water outlet 21a for discharging the water supplied from the water supply facility from the field to the outside such as an irrigation channel 26. A paddy field water level gauge 10 for measuring the water level of a paddy field (paddy field) 23 surrounded by . The water level is measured one by one by arranging one or more of them at the position and used as control data for the behavior of the water level in the field.
In addition, the installation position of the water level gauge in the field is an appropriate number along the water flow path (black arrow) that appears when water is supplied and drained in the field. In this case, a self-supporting water level gauge that is easy to install and remove can be used as the paddy field water level gauge installed in the field, except for permanent installations.

FIG. 12 is a diagram showing how to install the water level gauge for paddy fields according to the present invention in each paddy field. In FIG. 12, 10 is a paddy water gauge, 1 is a pressure sensor for measuring differential pressure, 2 is a diaphragm, 3a is an opening to the atmosphere, black arrows are atmospheric pressure, and white arrows are water pressure.
As shown in FIG. 12, the paddy field water level gauge 10 is located at a position h [m] higher than the ridge surrounding the paddy field or the top of the embankment of the irrigation channel along the paddy field that supplies water to and drains the paddy field. (referred to as installation height h).
This installation height h is set so that the air release port 3a is above the top of the ridge and irrigation channel, thereby eliminating the influence of wind entrained by the ridge and irrigation channel wall, and responsiveness to atmospheric pressure and its fluctuations. It allows you to communicate well and accurately.

The diaphragm is displaced by the difference between the transmitted atmospheric pressure and the water pressure obtained from the paddy water level sensed by the opening 2a of the diaphragm 2 of the differential pressure measuring pressure sensor 1, and the sensor element SC on the diaphragm 2 is displaced. sends the differential pressure signal to the pressure-water level conversion device 100 to become water level data, and the obtained water level data is sent to the water level data transfer device 101 for external transmission.
Therefore, the installation height h, along with the size of the opening to the atmosphere, has a great effect on the responsiveness and accuracy of differential pressure measurement.

Considering that the unevenness of the paddy surface is about ±5 cm, the range of the height h is preferably 0 to 10 cm. tends to decrease, and if the upper limit is exceeded, it is not desirable because it is greatly affected by the wind that blows over the field and causes problems in responsiveness and accuracy.

Furthermore, on the side of the pressure sensor of the water level gauge, the atmospheric release port 3a is arranged in the water when the paddy field is filled with water, or at a position satisfying the installation height h when there is no water in the paddy field. provided to be
In order to prevent obstacles such as mud and algae from entering, it is preferable to provide an air-permeable filter inside the air release port 3a.

In the method for measuring the water level of paddy fields, the water level gauge for paddy fields according to the present invention is characterized by being able to be installed at any location in the paddy field at any time by using a self-supporting jig.
FIG. 13 shows the configuration of the self-supporting water level gauge. (a) is a schematic diagram showing an example of a stand-type self-supporting water level gauge, and (b) is a schematic diagram showing an example of a socket-type self-supporting water level gauge. In FIG. 13, 7A is a stand-type self-standing jig, 7B is a socket-type self-standing jig, 7a is a water measuring port, 7b is a support rod, 7c is a water level gauge gripping arm, and 8 is a self-standing support for making the water level gauge stand on its own. Tool 9 is a spear that makes it easier to bury the water level gauge in the paddy field. In addition, self-supporting water level gauges that use a battery or a self-sufficient power source such as a solar battery are easy to handle and can easily form a water level gauge network.

The usage is to dig the buried part into the ground of the paddy field and fix it. can be
The pre-determined installation location is selected by recognizing changes in the water flow path due to the inclination and unevenness of the ground surface of the paddy field when water is supplied to and drained from the paddy field.

1 Differential pressure measurement pressure sensor 1a Sensor housing 1b Sensor atmospheric pressure port 1c Sealed liquid 1d Sensor water pressure port 2 Diaphragm 2a Diaphragm opening 3 Hollow housing 3a Atmospheric release port 3b Signal cable outlet 4 Signal cable 5, 5a Filter 6 Temperature sensor 7A Stand-type self-supporting jig 7B Socket-type self-supporting jig 7a Water measurement port 7b Support rod 7c Water level gauge gripping arm 8 Self-supporting support 9 Barrel 10, 10a to 10h Water level gauge for paddy field 20 Water supply facility 21 Drainage facility 21a Falling water Mouth 22 Ridge 23 Farm field (paddy field)
24 Cultivated crops (rice)
25 Main waterway 26 Irrigation waterway 30 Open to the atmosphere (integrated type)
100 Pressure-water level conversion device 101 Water level data transfer device 102 Water temperature detection device φ _A Size of opening to atmosphere φ _D Size of diaphragm opening φ ₁ Size of sensor water pressure opening SC Sensor element h (ridge of opening to atmosphere P1 Paddy field water level gauge installation location (plumbing equipment power supply range)
P2 Paddy field water level gauge installation location (ridge, near irrigation canal)
P3 Paddy field water level gauge installation location (in the field)

Claims (8)

A paddy water level measuring method for measuring the water level of stored water in a field for controlling water supply and drainage to a field surrounded by banks,
The water level measurement of the water stored in the field is performed by a water level gauge installed in the field,
The water level gauge is composed of a water level measurement unit, a signal processing unit, and a housing that houses the measurement unit,
The water level measuring unit comprises a differential pressure measuring pressure sensor equipped with a diaphragm having an opening, and a signal cable for transmitting the measured value measured by the sensor to the signal processing unit,
The housing is a hollow housing that houses the sensor in a watertight structure at one end, and has an opening to the atmosphere at the other end of the hollow housing. Prepared so that the air vent faces in the direction or the lateral direction perpendicular to the direction of the surface of the paddy field,
The signal processing unit comprises a pressure-water level conversion device and a water level data transfer device,
When the water level gauge is installed in the field, the water level gauge is installed so that the opening to the atmosphere of the water level gauge is located at a position higher than the height of the ridge,
Installed at a position where power can be supplied from a water supply device that controls water supply to the field,
and the hollow housing adopts an S-shaped form,
When the paddy water level gauge is installed in the paddy field, the paddy water level gauge is installed so that the end side provided with the differential pressure measuring pressure sensor is in contact with or parallel to the ground surface of the paddy field. A method for measuring the water level of paddy fields. 2. The paddy water level measuring method according to claim 1, wherein the size of said opening to the atmosphere is equal to or larger than the size of the opening of said diaphragm. 3. The paddy water level measuring method according to claim 1 or 2 , wherein a signal cable outlet is provided on the other end of said hollow housing having said air opening for drawing out said signal cable from the inside of said hollow housing to the outside. 4. The water level gauge according to any one of claims 1 to 3 , wherein the water level measurement unit of the water level gauge includes a temperature sensor, and the signal processing unit includes a water temperature detection device, and measures the water level compensated for changes in water pressure due to water temperature fluctuations. Paddy water level measurement method. 5. The paddy water level measuring method according to any one of claims 1 to 4 , wherein a hollow housing of said water level gauge is made of resin, and said signal processing unit is installed in said hollow housing. The paddy water level measuring method according to any one of claims 1 to 5 , wherein the water level gauge is a self-supporting water level gauge equipped with a self-supporting member. 7. A plurality of water level gauges are installed in the farm field at a position where power can be supplied from a water supply and drainage device that controls water supply and drainage to the farm field, near the bank, and in the farm field. paddy water level measurement method. 8. The paddy water level measuring method according to claim 7 , wherein the water level gauge in the field is arranged along a water flow path that appears during water supply and drainage of the water stored in the field, and measures the water level of the water stored in the field.

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