Irrigation system and control device

Abstract

To provide an irrigation system and a control device that can execute both drip irrigation and sprinkling irrigation.SOLUTION: In an irrigation system, the environment of each of a plurality of divided areas in a farm field is individually monitored by a monitoring part corresponding to each divided area. Supply of irrigation in each divided areas is individually controlled by corresponding monitoring parts and water supply valves 152. The irrigation system is equipped with distribution tubes 136 for which a plurality of through-holes for sprinkling irrigation onto the farm field are formed and which do not have a pressure correction mechanism. The irrigation system is equipped with water supply valves 152 which control the pressure of feed water flowing down to the distribution tubes 136. A microcomputer of the monitoring part controls a valve opening degree of the water supply valves 152 to control a splash distance of irrigation emitted from the distribution tubes 136 via the through-holes.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] The disclosure herein relates to an irrigation system and control device for controlling the supply of irrigation water to a field. [Background technology]

[0002] Patent Document 1 discloses an irrigation system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Pat. No. 1,077,266 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a drip tube with pressure compensation that has an emitter inside and achieves a constant water discharge rate. This device controls the supply and stop of irrigation water from the drip tube by opening and closing a valve that allows or blocks the supply of water to the drip tube. When the valve is open, water seeps out of the drip tube and irrigates the soil near the tube. However, according to Patent Document 1, the amount of irrigation water discharged from the tube cannot be instantly changed depending on the weather, soil conditions, crop growth conditions, etc.

[0005] It is an object of this disclosure to provide an irrigation system and control device that can perform both drip and trickle irrigation. [Means for solving the problem]

[0006] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference symbols in parentheses in the claims and in this section are merely examples showing the corresponding relationship with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope.

[0007] One of the disclosed irrigation systems is provided in a field (20) in which plants (30) are grown, and includes a distribution tube (136; 137) having a plurality of through holes for spraying irrigation water to the field and having no pressure compensation mechanism, a water supply valve (152) upstream of the distribution tube for controlling the pressure of the water flowing down to the distribution tube, and a control device (330) for controlling the valve opening of the water supply valve to control the amount of irrigation water released from the distribution tube through the through holes.

[0008] According to this irrigation system, the amount of irrigation is controlled by controlling the valve opening of the water supply valve upstream of the distribution tube that does not have a pressure compensation mechanism. By controlling the valve opening, irrigation can be performed by varying the amount of irrigation in sequence. Therefore, this irrigation system can perform both drip irrigation and sprinkler irrigation from the distribution tube.

[0009] One of the disclosed control devices includes a calculation unit (334) that determines the valve opening of a water supply valve (152) that controls the pressure of irrigation water flowing down into a distribution tube (136) having a plurality of through holes and no pressure compensation mechanism, upstream of the distribution tube, and an output unit (332) that outputs a control signal to the water supply valve to control the valve opening in order to control the amount of irrigation water released from the distribution tube through the through holes.

[0010] According to this control device, the calculation unit determines the valve opening, and the output unit outputs a control signal to the water supply valve to control the amount of irrigation water. This makes it possible to control the amount of irrigation water released from the distribution tube that does not have a pressure compensation mechanism, and irrigation can be performed by sequentially varying the amount of irrigation water. Therefore, this control device can perform both drip irrigation and sprinkler irrigation from the distribution tube. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a conceptual diagram showing an irrigation system of a first embodiment installed in a farm field. [Diagram 2] FIG. 2 is a partial view showing the water supply pipe and the pipe module. [Diagram 3] FIG. 1 is a block diagram of an irrigation system. [Figure 4] FIG. 2 is a block diagram showing a monitoring unit. [Diagram 5] FIG. [Figure 6] 13 is a flowchart illustrating a sensor process. [Figure 7] 13 is a flowchart illustrating an update process. [Figure 8] 13 is a flowchart illustrating a monitoring process. [Figure 9] 10 is a flowchart for explaining a water supply process. [Figure 10] 11 is a flowchart for explaining a watering process. [Figure 11] 13 is a flowchart illustrating a user update process. [Figure 12] 13 is a flowchart illustrating a forced update process. [Figure 13] FIG. 1 is a cross-sectional view showing a valve device that can be used as a water supply valve. [Figure 14] 3 is a diagram showing a configuration of a drive unit included in the valve device. FIG. [Figure 15] FIG. 2 is a perspective view showing a valve provided in the valve device. [Figure 16] FIG. 4 is a diagram showing the relationship between the rotation angle and the flow rate in the valve device. [Figure 17] 4 is a configuration diagram showing the positional relationship between a distribution tube, a water supply valve, and a water pressure sensor. FIG. [Figure 18] 10A and 10B are diagrams illustrating the relationship between the expansion and internal pressure of a distribution tube. [Figure 19] FIG. 11 is a diagram showing a passage configuration according to a second embodiment. [Figure 20] A diagram showing the relationship between the water discharge position in the distribution tube and the amount of irrigation water. [Figure 21] FIG. 11 is a diagram showing a passage configuration according to a third embodiment. [Figure 22] FIG. 13 is a diagram showing a passage configuration according to a fourth embodiment. [Figure 23] FIG. 13 is a diagram showing a passage configuration according to a fifth embodiment. [Figure 24] FIG. 13 is a diagram showing a passage configuration according to the sixth embodiment. [Diagram 25] A diagram showing the relationship between the water discharge position in the distribution tube and the amount of irrigation water. [Figure 26] A diagram showing the relationship between the water discharge position in the distribution tube and the amount of irrigation water. [Figure 27] A diagram showing the relationship between the water discharge position in the distribution tube and the amount of irrigation water. [Figure 28] FIG. 13 is a diagram showing a passage configuration according to the seventh embodiment. [Figure 29] FIG. 13 is a diagram showing a passage configuration according to the eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a number of embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other embodiments described previously may be applied to other parts of the configuration. In addition to combinations of parts that are specifically indicated as being possible in each embodiment, it is also possible to partially combine embodiments even if not indicated, as long as there is no particular problem with the combination.

[0013] First Embodiment A first embodiment disclosing an example of an irrigation system will be described with reference to Figs. 1 to 18. In the following, the three directions that are mutually orthogonal are referred to as the x-direction, y-direction, and z-direction. In this specification, the plane defined by the x-direction and y-direction is along the horizontal plane. The z-direction is along the vertical direction. In the drawings, the description of "direction" is omitted, and only x, y, and z are used.

[0014] <Field> The irrigation system 10 is applied to an outdoor field 20 cultivated on a hill or plain. As shown in FIG. 1, an embodiment in which the irrigation system 10 is applied to a field 20 cultivated on a plain will be described. The field 20 has an area of ​​several tens of square meters to several thousand square kilometers. The field 20 has a plurality of growing areas such as ridges extending in the x direction. These multiple growing areas extending in the x direction are arranged at intervals in the y direction. Seeds or seedlings of plants 30 are buried in each of the multiple growing areas. Examples of the plants 30 include grapes, corn, almonds, raspberries, leafy vegetables, and cotton.

[0015] A plurality of plants 30 are grown in one growing area. The plurality of plants 30 are lined up in a row in the x direction. In the following, the plurality of plants 30 lined up in a row in the x direction are referred to as a group of plants 31. In the field 20, the plurality of groups of plants 31 are lined up at intervals in the y direction. The minimum distance between the plurality of groups of plants 31 in the y direction is longer than the minimum distance between the plurality of plants 30 included in one group of plants 31 in the x direction. The distance between the plurality of groups of plants 31 in the y direction is changed in various ways depending on the type of plant 30 growing therein and the undulation and climate of the field 20. The distance between the plurality of groups of plants 31 in the y direction is about 1 m to 10 m. Even if the branches and leaves of the plants 30 grow thick in the y direction, at least a width sufficient for a person to move between two groups of plants 31 in the x direction is ensured.

[0016] <Irrigation system> The irrigation system 10 includes a water supply device 100 and a control device 200. The water supply device 100 supplies irrigation water to plants 30 in a field 20. The control device 200 determines the time and amount of irrigation water supplied from the water supply device 100 to the plants 30 during a watering period. The control device 200 determines the irrigation schedule for the water supply device 100.

[0017] <Water supply device> The water supply device 100 has a pump 110, a water supply pipe 130, and a piping module 150. The pump 110 is a water supply source that supplies irrigation water to the water supply pipe 130. The piping module 150 controls the discharge amount of the irrigation water supplied to the water supply pipe 130.

[0018] <Pump> The pump 110 is in a constant operating state. Alternatively, the pump 110 is in a daytime operating state. The pump 110 pumps out irrigation water stored in a tank or a reservoir, and supplies it to the water supply pipe 130. The irrigation water may be well water, river water, rainwater, city water, or the like. As described below, the water supply pipe 130 is provided with a plurality of water supply valves 152. When each of the plurality of water supply valves 152 is in a closed state and there is no leakage of irrigation water from the water supply pipe 130, the water supply pipe 130 is filled with irrigation water. At this time, the water pressure in the water supply pipe 130 becomes a value (also called pump pressure) that depends on the discharge capacity of the pump 110. When the water supply valve 152 changes from a closed state to an open state, irrigation water is discharged from the water supply pipe 130 to the field 20. When the amount of discharged irrigation water becomes stable on a time average basis, the water pressure in the water supply pipe 130 becomes a flow pressure that is lower than the pump pressure.

[0019] <Water supply piping> The water supply pipe 130 includes a main pipe 131 and a supply pipe 132. The main pipe 131 is connected to the pump 110. The supply pipe 132 is connected to the main pipe 131. The pump 110 supplies irrigation water from the main pipe 131 to the supply pipe 132. The irrigation water is supplied to the field 20 from the supply pipe 132.

[0020] <Main piping> The main pipe 131 includes a vertical pipe 133 and a horizontal pipe 134. The vertical pipe 133 extends in the y direction. The horizontal pipe 134 extends in the x direction. The vertical pipe 133 and the horizontal pipe 134 are connected to each other. Due to this configuration, irrigation water flows in the y direction and the x direction within the main pipe 131. In the example shown in FIG. 1, one vertical pipe 133 is connected to one pump 110. A plurality of horizontal pipes 134 extend in the x direction from the vertical pipe 133 extending in the y direction. The position of the horizontal pipe 134 in the z direction is set so as to be farther from the ground than the top of the mature plant 30.

[0021] 1 is merely one example of a passageway configuration for irrigation. The number of pumps 110 and vertical pipes 133 provided in the field 20, the number of vertical pipes 133 connected to one pump 110, the number of vertical pipes 133 connected to one horizontal pipe 134, and the positions of the horizontal pipes 134 and the vertical pipes 133 in the z direction are not particularly limited.

[0022] The multiple horizontal pipes 134 are lined up at a distance in the y direction. The shortest distance between the multiple horizontal pipes 134 in the y direction is equal to the shortest distance between the multiple groups of plants 31 in the y direction. One of the multiple horizontal pipes 134 is provided in one of the multiple groups of plants 31. The horizontal pipe 134 extends along the direction in which the multiple plants 30 included in the group of plants 31 are lined up. The supply pipe 132 is connected to this horizontal pipe 134.

[0023] <Supply piping> A plurality of supply pipes 132 are connected to one horizontal pipe 134. The plurality of supply pipes 132 connected to one horizontal pipe 134 are arranged in a line at a distance in the x direction. As shown in FIG. 2, the supply pipes 132 include a connecting pipe 135 and a distribution tube 136. The connecting pipe 135 extends downward in the z direction from the horizontal pipe 134. Two connecting ports that open in the x direction are formed at the tip side of the connecting pipe 135. The distribution tubes 136 are connected to these two connecting ports.

[0024] The distribution tube 136 does not have a pressure compensation mechanism that realizes a constant water discharge amount regardless of changes in water pressure. The water discharge amount from the through hole of the distribution tube 136 changes according to the water pressure. The distribution tube 136 includes a first distribution tube 136a connected to one of the two connection ports, and a second distribution tube 136b connected to the other of the two connection ports. The first distribution tube 136a and the second distribution tube 136b extend in opposite directions from the connection position with the connection pipe 135 in the x direction.

[0025] Each of the first distribution tube 136a and the second distribution tube 136b has a plurality of through holes that communicate between the inside of the tube, through which the irrigation water flows, and the outside. The plurality of through holes are arranged in a line at a predetermined interval in the axial direction of the tube in each tube. The through holes may also be arranged in a line at a predetermined interval in the circumferential direction of the tube in each tube.

[0026] The spacing between the multiple through holes in the axial direction (e.g., x direction) is equal to the spacing between the multiple plants 30 in the x direction. In the example shown in Fig. 2, each of the first distribution tube 136a and the second distribution tube 136b has three through holes lined up in the axial direction. The spacing between the multiple through holes and the spacing between the multiple plants 30 may be different. The number of through holes formed in each tube is not limited to three.

[0027] <Flow of irrigation water> The irrigation water supplied to the vertical pipe 133 by the pump 110 flows in the y direction inside the vertical pipe 133. This irrigation water is supplied to each of the multiple horizontal pipes 134 connected to the vertical pipe 133. The irrigation water flows in the x direction inside each of the multiple horizontal pipes 134. The irrigation water flowing inside the horizontal pipes 134 flows down into the distribution tube 136 via the connecting pipe 135. The irrigation water is discharged from each through-hole in each of the first distribution tube 136a and the second distribution tube 136b, and is supplied to the plant 30.

[0028] 1, each distribution tube is located closer to the ground of the field 20 than the top of the plant 30 in the height direction. The irrigation water supplied from the through holes of the first distribution tube 136a and the second distribution tube 136b is mainly supplied to the trunk and the root of the plant 30.

[0029] The through-holes are preferably provided at a position higher than the portion of each tube that faces the ground, so that the irrigation water discharged from the through-holes at such a position spreads in a radial direction relative to the central axis of the tube, and can be sprayed at a position distant from the tube.

[0030] <Piping module> 2, the piping module 150 is provided on the supply piping 132. The piping module 150 has a storage box 151, a water supply valve 152, and a water pressure sensor 153. The water supply valve 152 and the water pressure sensor 153 are stored inside the storage box 151.

[0031] <Water supply valve>, The water supply valve 152 is provided in the connecting pipe 135 at a position close to each of the first distribution tube 136a and the second distribution tube 136b. All of the through holes are provided between the water supply valve 152 and the tip portion of the first distribution tube 136a and the second distribution tube 136b that is separated from the connecting pipe 135.

[0032] When the water supply valve 152 is in the open state, the connecting pipe 135 and the through hole are in communication with each other. This allows irrigation water to be discharged from the through hole. Conversely, when the water supply valve 152 is in the closed state, communication between the connecting pipe 135 and the through hole is blocked. This stops the discharge of irrigation water from the through hole.

[0033] The water supply valve 152 provided on the first distribution tube 136a and the water supply valve 152 provided on the second distribution tube 136b are independently controlled in opening degree by the control device 200. By such opening degree control, the discharge of irrigation water from the through hole of the first distribution tube 136a and the discharge of irrigation water from the through hole of the second distribution tube 136b are independently controlled.

[0034] The control device 200 arbitrarily controls the valve opening of the water supply valve 152 between a predetermined opening and full opening. The water supply valve 152 is a flow rate control valve or a pressure control valve that can precisely vary the flow rate by adjusting the downstream or upstream pressure. The predetermined opening is set to a value including a slightly open opening or a 0% opening, that is, a fully closed state. The control device 200 controls the discharge flow rate or discharge flow velocity per unit time discharged from each through-hole by controlling the valve opening of the water supply valve 152. By this control, the control device 200 can control the water flight distance, which is the distance at which the irrigation water discharged from the distribution tube 136 lands after moving away from the distribution tube 136. The water flight distance is the distance between the distribution tube 136 and the soil landing point of the irrigation water that has flown out of the distribution tube 136 through the through-hole. This technology for controlling the water flight distance allows efficient irrigation to be performed in places that need irrigation, which also contributes to water conservation.

[0035] The control device 200 determines the irrigation water flight distance based on the type of plant 30 to which irrigation water is to be supplied, the range of the till layer in the field 20, and the like. The control device 200 controls the valve opening of the water supply valve 152 so as to obtain the determined water flight distance. For example, the valve opening of the water supply valve 152 is controlled to increase the water flight distance when the plant 30 has wide roots or the till layer is shallow and wide. The valve opening of the water supply valve 152 is also controlled to reduce the water flight distance when the plant 30 has deep roots or the till layer is located near the distribution tube 136. The water flight distance can be rephrased as the irrigation distance.

[0036] <Water pressure sensor> The water pressure sensor 153 is provided in the vicinity of the portion where the first distribution tube 136a and the second distribution tube 136b are connected in the connecting pipe 135. Each water pressure sensor 153 is a pressure sensor that detects the water pressure in the connecting pipe 135. The water pressure detected by the water pressure sensor 153 is output to the control device 200. The water pressure sensor 153 may be provided between the connecting portion of the first distribution tube 136a with the connecting pipe 135 and the water supply valve 152, or between the connecting portion of the second distribution tube 136b with the connecting pipe 135 and the water supply valve 152. The water pressure sensor 153 may be provided in the vicinity of the connecting portion of the connecting pipe 135 with the horizontal pipe 134. The water pressure sensor 153 may be located on the horizontal pipe 134 side of the water supply valve 152 in the flow path of the irrigation water in the supply pipe 132.

[0037] When the water supply valve 152 is closed and the connecting pipe 135 is filled with irrigation water, the pump pressure is detected by the water pressure sensor 153. When the water supply valve 152 changes from a closed state to an open state, irrigation water is discharged from the distribution tube 136. When the time-averaged amount of irrigation water discharge stabilizes, the flow pressure is detected by the water pressure sensor 153. When the water supply valve 152 changes from an open state to a closed state, the discharge of irrigation water from the water supply pipe 130 stops. The water pressure in the water supply pipe 130 gradually recovers from the flow pressure to the pump pressure. The water pressure sensor 153 detects the water pressure during the transitional period when the water pressure gradually recovers from the flow pressure to the pump pressure.

[0038] If a break occurs in the water supply pipe 130 or the water supply valve 152 and irrigation water leaks from the broken part, the water pressure detected by the water pressure sensor 153 will decrease. This makes it possible to detect whether or not a break has occurred. This breakage detection process is executed by the control device 200. The irrigation system 10 may be configured to include a flow sensor that detects the flow rate of the fluid flowing through the passage, instead of the water pressure sensor 153. The irrigation system 10 feedback-controls the valve opening of the water supply valve 152 using the detection values ​​of the water pressure sensor 153 and the flow sensor.

[0039] <Control device> 1 and 3, the control device 200 includes a monitoring unit 300, an integrated communication unit 400, an information storage unit 500, and an integrated calculation unit 600. In the drawings, the integrated communication unit 400 is denoted as ICD. The control device 200 has a plurality of monitoring units 300. Each of the plurality of monitoring units 300 corresponds to a predetermined divided area in the farm field 20. One monitoring unit 300 is provided corresponding to one piping module 150, for example. The monitoring unit 300 and the piping module 150 are electrically connected to each other.

[0040] The water pressure detected by the water pressure sensor 153 is input to the monitoring unit 300. The monitoring unit 300 detects an environmental value, which is a physical quantity related to the environment of the farm field 20. Each of the multiple monitoring units 300 outputs the water pressure and the environmental value to the integrated communication unit 400 by wireless communication.

[0041] The integrated communication unit 400 outputs the water pressure and environmental values ​​input from each monitoring unit 300 to the information storage unit 500 via wireless communication. The information storage unit 500 stores the water pressure and environmental values. An example of the information storage unit 500 is a so-called cloud. The integrated calculation unit 600 reads out various information such as the water pressure and environmental values ​​stored in the information storage unit 500. The integrated calculation unit 600 appropriately processes the read out information and displays the information and processing results on a monitor 700 of the user's smartphone or personal computer.

[0042] The integrated calculation unit 600 is included in a user's smartphone or personal computer. The integrated calculation unit 600 has an information processing calculation device 610, a memory 620, and a communication device 630. In the drawings, the information processing calculation device 610 is represented as IPCE, the memory 620 as MM, and the communication device 630 as CD. The information processing calculation device 610 includes a processor. The information processing calculation device 610 performs calculation processing related to irrigation processing. This function is realized by downloading an irrigation application program to the information processing calculation device 610.

[0043] The memory 620 is a non-transient substantial storage medium that non-temporarily stores various programs and various information that can be read by a computer or a processor. The memory 620 has a volatile memory and a non-volatile memory. The memory 620 stores various information input to the communication device 630 and the processing results of the information processing device 610. The information processing device 610 executes various arithmetic processes using the information stored in the memory 620.

[0044] The communication device 630 has a wireless communication function. The communication device 630 converts a received wireless signal into an electric signal and outputs it to the information processing device 610. The communication device 630 outputs the processing result of the information processing device 610 as a wireless signal. Hereinafter, the technical content of this embodiment will be described using the integrated calculation unit 600 as a general term without distinguishing between the information processing device 610, the memory 620, and the communication device 630. The information processing device 610 corresponds to the processing unit.

[0045] A user inputs user instructions related to irrigation treatment and irrigation schedules to the integrated calculation unit 600 using an input device 800 such as a touch panel or a keyboard. The integrated calculation unit 600 outputs irrigation treatment commands and determines the irrigation schedule based on the user instructions and various information read from the information storage unit 500. If there are no instructions from the user, the integrated calculation unit 600 automatically determines the irrigation schedule based on various information.

[0046] When the integrated calculation unit 600 detects an irrigation processing command or determines that it is time to start supplying irrigation water in the irrigation schedule, it outputs an instruction signal to the information storage unit 500 to control the water supply valve 152. This instruction signal is input from the information storage unit 500 to the monitoring unit 300 via the integrated communication unit 400. The monitoring unit 300 controls whether to output a water supply signal to the water supply valve 152 based on the instruction signal. This controls the open / close state of the water supply valve 152. As a result, the supply of irrigation water to the field 20 is controlled. At least one of the instruction signal and the water supply signal corresponds to a control signal.

[0047] <Divided area> As shown in Fig. 1, one monitoring unit 300 is provided for each supply pipe 132. As shown in Fig. 3 as an example, the multiple monitoring units 300, together with the water supply valves 152 and water pressure sensors 153 provided in the multiple piping modules 150, are arranged in a matrix in the field 20 with the x direction as the row direction and the y direction as the column direction.

[0048] With this configuration, the environment of each of the multiple divided areas separated by the row and column directions is monitored individually by the monitoring unit 300 corresponding to each divided area. Furthermore, the supply of irrigation water to each of the multiple divided areas is individually controlled by the corresponding monitoring unit 300 and piping module 150.

[0049] <Monitoring section> 3 and 4, the monitoring unit 300 has an environmental sensor 310 and a control unit 320. The water supply valve 152 and the water pressure sensor 153 of the piping module 150 are electrically connected to the control unit 320. In the drawings, the environmental sensor 310 is represented as ES, the water supply valve 152 as WB, and the water pressure sensor 153 as WPS.

[0050] The multiple environmental sensors 310 are arranged in a matrix in the farm field 20 together with the piping module 150. Each environmental sensor 310 detects an environmental value for each of the multiple divided areas. Each water pressure sensor 153 detects the water pressure for each of the multiple divided areas. The detected environmental value and water pressure for each of the multiple divided areas are stored in the information storage unit 500.

[0051] 4, the control unit 320 includes a microcomputer 330, a communication unit 340, an RTC 350, and a power generation unit 360. The microcomputer is an abbreviation for microcomputer. The RTC is an abbreviation for Real Time Clock. In the drawing, the communication unit 340 is represented as CDP.

[0052] Environmental values ​​and water pressure are input to microcomputer 330. Microcomputer 330 outputs these environmental values ​​and water pressure to integrated communication unit 400 via communication unit 340. An instruction signal is input to microcomputer 330 from integrated communication unit 400. Microcomputer 330 outputs a water supply signal to water supply valve 152 based on this instruction signal. Microcomputer 330 corresponds to an arithmetic processing unit. Microcomputer 330 is a control device that controls the operation of water supply valve 152.

[0053] The microcomputer 330 has a sleep mode and a normal mode as operation modes. In the sleep mode, the microcomputer 330 stops processing. In the normal mode, the microcomputer 330 executes processing. The normal mode consumes more power than the sleep mode.

[0054] The communication unit 340 performs wireless communication with the integrated communication unit 400. The communication unit 340 outputs the electrical signal output from the microcomputer 330 as a wireless signal to the integrated communication unit 400. At the same time, the communication unit 340 receives the wireless signal output from the integrated communication unit 400 and converts it into an electrical signal. The communication unit 340 outputs the electrical signal to the microcomputer 330. If the electrical signal includes an instruction signal, the microcomputer 330 switches from the sleep mode to the normal mode.

[0055] The RTC 350 has a clock function that keeps time and a timer function that measures time. When a preset time arrives or a preset time has elapsed, the RTC 350 outputs a wake-up signal to the microcomputer 330. When this wake-up signal is input to the microcomputer 330 in the sleep mode, the microcomputer 330 switches from the sleep mode to the normal mode.

[0056] The power generation unit 360 converts the light energy obtained by the solar cell into electrical energy. The power generation unit 360 functions as a power supply source for the monitoring unit 300. Power is constantly supplied from the power generation unit 360 to the RTC 350. This prevents the clock function and timer function of the RTC 350 from being impaired.

[0057] <Environmental sensor> One of the environmental values ​​that is expected to differ for each divided area of ​​the field 20 is soil moisture content. The environmental sensor 310 detects the environmental value in the corresponding divided area. The environmental sensor 310 includes a soil sensor 311 that detects the soil moisture content, etc. The multiple soil sensors 311 detect the soil moisture content in the multiple divided areas arranged in the field 20. In the drawings, the soil sensor 311 is represented as SMS.

[0058] The amount of solar radiation is one of the environmental values ​​that is expected to differ for each divided area depending on the undulations of the field 20 and the growth conditions of the plants 30. In this specification, each environmental sensor 310 is equipped with a solar radiation sensor 312 that detects the amount of solar radiation. The multiple solar radiation sensors 312 detect the amount of solar radiation in the multiple divided areas of the field 20. In the drawings, the solar radiation sensor 312 is denoted as SRS.

[0059] The soil moisture distribution and solar radiation distribution in the field 20 are displayed as a map on the monitor 700 by arranging the soil moisture amounts and solar radiation amounts detected in the multiple divided areas in a matrix. Similarly, the water pressure distribution in the water supply pipes 130 in the field 20 is displayed as a map on the monitor 700 by arranging the water pressures detected by the multiple water pressure sensors 153 in a matrix. Such map display processing is performed by the integrated calculation unit 600.

[0060] The environmental values ​​in the field 20 include the amount of rainfall, temperature, humidity, air pressure, and wind volume. Sensors for detecting these environmental values ​​are a rain sensor 313, a temperature sensor 314, a humidity sensor 315, an air pressure sensor 316, and a wind sensor 317. These are included in at least one environmental sensor 310 of the multiple monitoring units 300.

[0061] The environmental sensor 310 of the monitoring unit 300 includes various sensors that detect these environmental values ​​of the entire field 20. An example of the environmental sensor 310 is shown in Fig. 4. In the drawing, the rain sensor 313 is represented as RS, the temperature sensor 314 as TS, the humidity sensor 315 as MS, the air pressure sensor 316 as PS, and the wind sensor 317 as WS. The wind sensor 317 may be configured to detect not only the air volume but also the wind direction. A configuration may be adopted in which at least one of the rain sensor 313, temperature sensor 314, humidity sensor 315, air pressure sensor 316, and wind sensor 317 is arranged in a matrix in the field 20.

[0062] This configuration is effective when the amount of rainfall, temperature, humidity, air pressure, and wind volume are likely to change significantly for each divided area because the field 20 is large, has steep undulations, or experiences drastic weather changes in the field 20. By arranging the amount of rainfall, temperature, humidity, air pressure, and wind volume detected by these sensors in a matrix, it becomes possible to display these environmental values ​​as a map on the monitor 700. The outputs of these sensors are output to the communication unit 340 via the integrated communication unit 400. At the same time, the outputs of these sensors are stored in the information storage unit 500 via the integrated communication unit 400.

[0063] <Soil moisture content> Among the various environmental values ​​described above, the environmental values ​​controlled by the irrigation system 10 include soil moisture content. The irrigation system 10 controls the time and amount of irrigation water supply for each divided area. In this way, the soil moisture content for each divided area is controlled individually.

[0064] The plant 30 has its roots in the till layer of the field 20. The growth of the plant 30 depends on the amount of water contained in the soil of this till layer (also called the soil moisture content). If the soil moisture content exceeds the growth inhibition moisture point, the plant 30 will develop disease. If the soil moisture content falls below the permanent wilting point, the plant 30 will not recover from wilting. The growth inhibition moisture point and the permanent wilting point differ depending on the type of plant 30, but their values ​​are known. These values ​​are stored in the information storage unit 500.

[0065] The current value of the soil moisture content is detected by the soil sensor 311. Physical quantities related to the soil moisture content include the soil moisture tension (pF value) and the soil dielectric constant (ε). The soil sensor 311 in this specification detects the pF value.

[0066] The soil moisture content in the plowed soil layer increases or decreases due to environmental changes in the field 20. When rain falls on the field 20, the soil moisture content increases. When water evaporates from the plowed soil layer, the soil moisture content decreases. Also, when the plants 30 absorb the moisture or when the water permeates below the plowed soil layer, the soil moisture content decreases. The amount of rain falling on the plowed soil layer (rainfall amount) is detected by the rain sensor 313. The amount of moisture evaporating from the plowed soil layer (evaporation amount) depends on the amount of solar radiation, temperature, humidity, and wind volume. These are detected by the solar radiation sensor 312, the temperature sensor 314, the humidity sensor 315, and the wind sensor 317.

[0067] The amount of water absorbed by the plant 30 per unit time can be estimated in advance based on the type of plant 30. The amount of water that permeates below the plow soil layer per unit time can be estimated in advance based on the water retention capacity of the soil. These estimated values ​​are stored in the information storage unit 500.

[0068] As described above, the environmental sensor 310 detects the current value of the soil moisture content in the plowed soil layer, the increase from the current value of the soil moisture content in the plowed soil layer due to environmental changes, and the predicted value relating to the predicted decrease. These are stored as environmental values ​​in the information storage unit 500. The information storage unit 500 stores the growth inhibition moisture point and permanent wilting point of the plant 30, the amount of water absorbed by the plant 30 per unit time, and the moisture retention capacity of the soil. The above-mentioned instructions from the user (user instructions) are stored in the information storage unit 500. In this way, the information storage unit 500 stores various information for determining the watering schedule.

[0069] <Microcomputer> 4, the microcomputer 330 includes an acquisition unit 331, a signal output unit 332, a storage unit 333, and a processing unit 334. In the drawing, the acquisition unit 331 is represented as AD, the signal output unit 332 as SOU, the storage unit 333 as MU, and the processing unit 334 as PU.

[0070] An environmental value detected by the environmental sensor 310 is input to the acquisition unit 331. A water pressure detected by the water pressure sensor 153 is input to the acquisition unit 331. The acquisition unit 331 is electrically connected to each of the environmental sensor 310 and the water pressure sensor 153. The wire 160 shown in FIG. 1 is an example of a wire connecting the acquisition unit 331 and the soil sensor 311, and a wire connecting the acquisition unit 331 and the water pressure sensor 153.

[0071] The signal output unit 332 is electrically connected to the water supply valve 152. A control signal (water supply signal) for controlling the valve opening degree of the water supply valve 152 is output from the signal output unit 332 to the water supply valve 152. When no water supply signal is input, the water supply valve 152 is in a closed state. When a water supply signal is input, the water supply valve 152 is in an open state.

[0072] The memory unit 333 is a non-transient substantial storage medium that non-temporarily stores programs and data that can be read by a computer or a processor. The memory unit 333 has a volatile memory and a non-volatile memory. The memory unit 333 stores a program for the processing unit 334 to execute arithmetic processing. This program includes at least a part of the above-mentioned irrigation application program. The memory unit 333 temporarily stores data when the processing unit 334 executes arithmetic processing. The memory unit 333 stores various data input to the acquisition unit 331 and the communication unit 340, respectively, and the acquisition times of the various data.

[0073] When a wake-up signal is input from the RTC 350, the processing unit 334 goes from the sleep mode to the normal mode. In the normal mode, the processing unit 334 reads the programs and various data stored in the memory unit 333 and executes arithmetic processing. This arithmetic processing includes the calculation of the valve opening required for the water splashed through the through-hole of the distribution tube 136 to reach the desired irrigation position. The processing unit 334 corresponds to a calculation unit.

[0074] The processing unit 334 reads out from the RTC 350 the acquisition times of the various sensor signals input to the acquisition unit 331 and the instruction signal input to the communication unit 340. The processing unit 334 causes the storage unit 333 to store the instruction signal and the acquisition time.

[0075] The processing unit 334 stores the environmental values ​​and water pressure input from the environmental sensor 310 and the water pressure sensor 153, and the times at which they were acquired, in the information storage unit 500 via the communication unit 340 and the integrated communication unit 400. The processing unit 334 outputs a water supply signal to the water supply valve 152 via the signal output unit 332, based on an instruction signal input from the integrated calculation unit 600 via the information storage unit 500, the integrated communication unit 400, and the communication unit 340.

[0076] <Communications Department> The communication unit 340 converts the electrical signal input from the processing unit 334 into a wireless signal. The communication unit 340 outputs the wireless signal to the integrated communication unit 400. The communication unit 340 converts the wireless signal output from the integrated communication unit 400 into an electrical signal. The communication unit 340 outputs the electrical signal to the processing unit 334.

[0077] The wireless signal output by communication unit 340 includes address 341 and data 342, which are simply shown in Fig. 5. In the drawing, address 341 is represented as ADD, and data 342 is represented as DAT.

[0078] 3, wireless signals are transmitted and received between the multiple communication units 340 and the integrated communication unit 400. An address 341 included in the wireless signal is an identification code indicating which of the multiple communication units 340 the signal was output from. In other words, the address included in the wireless signal is an identification code indicating which of the multiple processing units 334 the signal was output from. A unique address 341 is stored in each of the multiple storage units 333.

[0079] The wireless signal output from the integrated communication unit 400 also contains an address 341. The data 342 of this wireless signal contains an instruction signal. This wireless signal is received by each of the multiple communication units 340. This wireless signal is converted into an electrical signal by each of the multiple communication units 340. This electrical signal is then input to each of the multiple processing units 334. Of the multiple processing units 334, only the processing unit 334 having the same address 341 as the address 341 contained in the electrical signal executes arithmetic processing based on the electrical signal.

[0080] As described later, the microcomputer 330 operates intermittently by alternately switching between a sleep mode and a normal mode. For this reason, wireless communication between the communication unit 340 and the integrated communication unit 400 is not performed frequently. The time intervals at which wireless communication is performed between the communication unit 340 and the integrated communication unit 400 are long. This makes it possible to increase the amount of data that can be included in the data 342 in one wireless communication.

[0081] <Power Generation Division> The power generation unit 360 includes a solar cell 361, a power storage unit 362, a current sensor 363, and a power sensor 364. In the drawings, the solar cell 361 is represented as SB, the power storage unit 362 as ESU, the current sensor 363 as CS, and the power sensor 364 as PS. The solar cell 361 converts light energy into electrical energy. The power storage unit 362 stores the electrical energy (power). The power stored in the power storage unit 362 is utilized as power to drive the monitoring unit 300.

[0082] Current sensor 363 detects the current output from solar cell 361 to power storage unit 362. Power sensor 364 detects the power output from power storage unit 362. Processing unit 334 stores the detected current value and power value in information storage unit 500 via communication unit 340 and integrated communication unit 400. The driving power of monitoring unit 300 depends on the power generated by power generation unit 360. For this reason, if the amount of light incident on power generation unit 360 is small, the driving power of monitoring unit 300 may be insufficient. To avoid this, microcomputer 330 of monitoring unit 300 performs intermittent driving.

[0083] <rtc> The RTC 350 outputs a wake-up signal to the microcomputer 330 every time the above-mentioned intermittent drive time interval (drive cycle) elapses. This causes the microcomputer 330 to alternate between sleep mode and normal mode. The drive cycle is determined by the integrated calculation unit 600 according to the amount of power stored in the power storage unit 362 (amount of stored power). In other words, the intermittent drive interval is determined by the integrated calculation unit 600 according to the amount of stored power.

[0084] The integrated calculation unit 600 calculates the amount of stored power based on the power stored in the information storage unit 500. The integrated calculation unit 600 sets a longer intermittent drive interval as the amount of stored power decreases. The integrated calculation unit 600 sets a shorter intermittent drive interval as the amount of stored power increases. The integrated calculation unit 600 includes the intermittent drive interval in an instruction signal. When the processing unit 334 of the microcomputer 330 acquires this instruction signal, the processing unit 334 adjusts the intermittent drive interval. The processing unit 334 adjusts the drive cycle of the RTC 350. It is rare for the environment of the field 20 to change drastically in units of a few seconds. For this reason, the intermittent drive interval is set to a unit of tens of seconds to tens of hours. Accordingly, the time interval for wireless communication is also set to a unit of tens of seconds to tens of hours.

[0085] <Driving the irrigation system> In the irrigation system 10, signals are transmitted and received between the multiple monitoring units 300 and the integrated calculation unit 600, and various data are stored in the information storage unit 500. Each of the multiple monitoring units 300 and the integrated calculation unit 600 executes a cycle task that is processed for each drive period, and an event task that is processed suddenly.

[0086] These cycle tasks and event tasks have a processing priority order. When the processing timing of these tasks becomes the same, the event task processing is given priority over the cycle task processing. As cycle tasks, each monitoring unit 300 executes the sensor processing shown in FIG. 6. The integrated calculation unit 600 executes the update processing shown in FIG. 7. As event tasks, each monitoring unit 300 executes the monitoring processing shown in FIG. 8 and the water supply processing shown in FIG. 9. The integrated calculation unit 600 executes the irrigation processing shown in FIG. 10, the user update processing shown in FIG. 11, and the forced update processing shown in FIG. 12.

[0087] The sensor processing and update processing as cycle tasks will be described below with reference to Figures 6 and 7. In each diagram showing a flowchart, the start is indicated by S and the end is indicated by E.

[0088] <Sensor processing> Before the start shown in FIG. 6, the microcomputer 330 of the monitoring unit 300 is in a sleep mode, and a wake-up signal is input from the RTC 350 to the microcomputer 330. This causes the microcomputer 330 to switch from the sleep mode to the normal mode. At the same time, the microcomputer 330 starts executing the sensor processing shown in FIG. 6. This sensor processing is executed at the intermittent drive interval of the microcomputer 330. In step S10, the sensor signals input from the various sensors are acquired, and the acquisition times of the sensor signals are acquired based on the output of the RTC 350. In addition, in step S20, the acquired sensor signals and the acquisition times are stored. In step S30, the sensor signals and the acquisition times as sensor information are output from the communication unit 340 to the integrated communication unit 400 by wireless communication. This sensor information is stored in the information storage unit 500 by the integrated communication unit 400. The microcomputer 330 transitions to a sleep mode and ends the sensor processing.

[0089] <Update process> The integrated calculation unit 600 executes the update process shown in FIG. 7 every time an update period elapses. This update period is approximately the same as the intermittent drive interval of the microcomputer 330. In step S110, various information stored in the information storage unit 500 is read. In the next step S120, the irrigation schedule of each of the multiple monitoring units 300 is updated based on the various information read. The integrated calculation unit 600 also updates the sensor processing in each monitoring unit 300. The integrated calculation unit 600 updates the intermittent drive interval, which corresponds to the timing for executing the sensor processing. The integrated calculation unit 600 holds the updated irrigation schedule and intermittent drive interval itself, and stores them in the information storage unit 500, and ends the update process. As described above, the sensor information, the irrigation schedule, and the intermittent drive interval are updated by the cycle task.

[0090] Next, the monitoring process, water supply process, irrigation process, user update process, and forced update process as event tasks will be described with reference to Fig. 8 to Fig. 12. The monitoring process, water supply process, and irrigation process are each executed during the daytime to avoid exhaustion of the driving power of the monitoring unit 300. Whether or not it is daytime can be determined based on the current time and the amount of solar radiation detected by the solar radiation sensor 312, etc.

[0091] <Monitoring process> 8, the microcomputer 330 of each monitoring unit 300 is in sleep mode. An instruction signal is input to the microcomputer 330 from the integrated calculation unit 600 via wireless communication. As a result, the microcomputer 330 switches from the sleep mode to the normal mode and starts executing the monitoring process shown in FIG.

[0092] In step S210, the input instruction signal and the time of acquisition are stored. In the next step S220, it is determined whether or not the instruction signal includes a water supply instruction to change the water supply valve 152 from a closed state to an open state. If the instruction signal includes a water supply instruction, the process proceeds to step S230. If the instruction signal does not include a water supply instruction, the process proceeds to step S240.

[0093] In step S230, the water supply process shown in Fig. 9 is executed. That is, in step S231, the microcomputer 330 outputs a water supply signal to the water supply valve 152 in accordance with the water supply instruction. In step S232, the microcomputer 330 determines whether or not the water supply time included in the instruction signal has elapsed. If the water supply time has not elapsed, the microcomputer 330 continues to output the water supply signal to the water supply valve 152. If the water supply time has elapsed, the process proceeds to step S233.

[0094] In step S233, the output of the water supply signal is stopped and the water supply process is terminated. In the next step S240, it is determined whether or not the instruction signal includes an instruction to update the intermittent drive interval. If the instruction signal includes an instruction to update the intermittent drive interval, the process proceeds to step S250. If the instruction signal does not include an instruction to update the intermittent drive interval, the process proceeds to step S260. The above-mentioned instruction to update the intermittent drive interval is output as an instruction signal from the integrated calculation unit 600 or the information storage unit 500 to each monitoring unit 300 periodically or irregularly.

[0095] In step S250, the processing unit 334 of the microcomputer 330 adjusts the time interval for outputting a wake-up signal from the RTC 350. In the next step S260, the sensor processing described with reference to FIG. 6 is executed. If the water supply processing in step S230 is executed, the environmental value after irrigation is supplied is detected in step S260. If the water supply processing in step S230 is not executed, the environmental value when irrigation is not being supplied is detected in step S260. This environmental value is stored in the information storage unit 500. After executing the sensor processing, the microcomputer 330 transitions to a sleep mode and ends the monitoring processing.

[0096] <Irrigation treatment> The integrated calculation unit 600 executes the watering process shown in Fig. 10 each time it is time to supply water in the watering schedule of each monitoring unit 300. In step S310, the integrated calculation unit 600 outputs a water supply signal including a water supply instruction to the monitoring unit 300 of the multiple monitoring units 300 that is in the divided area to which water is to be supplied. In the next step S320, the water supply instruction includes the start of output of the water supply signal and the output time of the water supply signal (water supply time). The monitoring unit 300 that receives this water supply instruction executes the monitoring process described based on Fig. 8.

[0097] When the process proceeds to step S320, the integrated calculation unit 600 goes into a standby state until the monitoring process of the monitoring unit 300 ends. When the monitoring process ends, the process proceeds to step S330. The determination as to whether the monitoring process has ended is made, for example, based on whether a time that is expected for the monitoring process to end has elapsed. The determination as to whether the monitoring process has ended can be made by inquiring of the monitoring unit 300. There is no particular limitation on the method of determining whether the monitoring process has ended.

[0098] <User update process> The integrated calculation unit 600 executes the user update process shown in Fig. 11 when a user instruction relating to adjustment of the watering schedule or the intermittent drive interval is input from the input device 800. In step S410, the integrated calculation unit 600 stores the input user instruction in the information storage unit 500. In the next step S420, the update process described with reference to Fig. 7 is executed. As a result, the watering schedule and the intermittent drive interval are updated based on the user instruction.

[0099] <Forced update process> The integrated calculation unit 600 executes the forced update process shown in Fig. 12 when a user instruction related to updating the watering schedule and the intermittent drive interval is input. In step S510, the integrated calculation unit 600 outputs a request signal including a request instruction requesting execution of sensor processing. This request signal is output to the monitoring unit 300 by wireless communication. In step S520, the integrated calculation unit 600 goes into a standby state until the sensor processing of the monitoring unit 300 is completed.

[0100] If the sensor processing has ended, the process proceeds to step S530. The determination as to whether the sensor processing has ended can be made, for example, based on whether the time required for the sensor processing to end has elapsed. Alternatively, the determination can be made by inquiring of the monitoring unit 300 as to whether the sensor processing has ended. There are no particular limitations on the method of determining whether the sensor processing has ended. In step S530, the update process described with reference to FIG. 7 is executed. As a result, the watering schedule and the intermittent drive interval are updated based on various data at the time of the user's update request.

[0101] The monitoring unit 300 judges whether water is coming out of the distribution tube 136 in the water supply process shown in Fig. 9 and the irrigation process shown in Fig. 10, and performs processing according to the judgment result. The monitoring unit 300 judges whether water is being discharged based on the water pressure detected by the water pressure sensor 153. If the monitoring unit 300 judges that the water pressure detected by the water pressure sensor 153 exceeds the abnormal pressure value, it fully closes the water supply valve 152 during irrigation and stops irrigation. The abnormal pressure value is set to a pressure value that is impossible when water is being discharged from the distribution tube 136 or a pressure value when water has nowhere to go and is not released to the outside. The abnormal pressure value is stored in the memory unit 333 in advance.

[0102] When the water pressure exceeds the abnormal pressure value, the monitoring unit 300 performs further irrigation from the adjacent distribution tube 136 adjacent to the distribution tube 136 for which irrigation has been stopped. For example, the adjacent distribution tube 136 is adjacent to the distribution tube 136 for which irrigation has been stopped in a direction perpendicular to the axial direction of the tube. The monitoring unit 300 controls the valve opening of the water supply valve 152 that can supply water to the adjacent distribution tube 136 to a value that provides a water jump distance that reaches the target irrigation position that was intended for the stopped irrigation.

[0103] In this way, when irrigation water is not being released from a distribution tube 136, the control device controls the valve opening of the water supply valve 152 that controls the pressure of the supply water flowing down to the adjacent distribution tube 136 adjacent to the distribution tube 136 from which irrigation water is not being released. By controlling the valve opening, the control device controls the flight distance of the irrigation water released from the adjacent distribution tube 136 so that the irrigation water that was not released reaches the target irrigation position that was intended. This control makes it possible to provide an irrigation system 10 that can eliminate irrigation problems caused by clogging of the piping or distribution tube 136 or a malfunction of the water supply valve 152.

[0104] <Individual irrigation treatment> As described above with reference to Figs. 6 to 12, the integrated calculation unit 600 determines a watering schedule for each of a plurality of divided areas. The integrated calculation unit 600 controls the supply of irrigation water based on each irrigation schedule. Although the irrigation schedule for each divided area is determined by the integrated calculation unit 600, a configuration may be adopted in which the supply of irrigation water based on each irrigation schedule is individually controlled by each monitoring unit 300.

[0105] <Independent update> As a further example, a configuration may be adopted in which the watering schedule for each divided area is determined independently by the corresponding monitoring unit 300. In such a configuration, each monitoring unit 300 executes the update process shown in FIG.

[0106] <Weather forecast and irrigation schedule> The information storage unit 500 stores the current soil moisture content value, a predicted decrease in the soil moisture content, and user instructions. The information storage unit 500 stores the growth inhibition moisture point and permanent wilting point of the plant 30, the amount of water absorbed by the plant 30 per unit time, and the soil's moisture retention capacity. In addition to these, the information storage unit 500 stores a weather forecast for the field 20 output and distributed from an external information source 1000. In the drawings, the external information source 1000 is denoted as ESI.

[0107] 7, the integrated calculation unit 600 reads out various information including the weather forecast from the information storage unit 500. The integrated calculation unit 600 determines the watering schedule for each monitoring unit 300 in step S120.

[0108] <Target and Estimated Values> The integrated calculation unit 600 calculates a target value and an estimated value of the soil moisture content when determining the irrigation schedule. The target value of the soil moisture content is, as a matter of course, set to a value between the growth inhibition moisture point and the permanent wilting point. In order to attempt to grow the plant 30 in a healthy manner, the target value of the soil moisture content is set to a value somewhat away from each of the growth inhibition moisture point and the permanent wilting point, which are theoretical values.

[0109] The integration calculation unit 600 sets an upper limit target value on the growth inhibition moisture point side and a lower limit target value on the permanent wilting point side as the target values ​​of the soil moisture content. The integration calculation unit 600 determines the irrigation schedule so that the estimated value of the soil moisture content is between the upper limit target value and the lower limit target value during the irrigation period of the irrigation schedule. Even if it is predicted that the estimated value of the soil moisture content will exceed the upper limit target value due to rainfall, the integration calculation unit 600 determines the irrigation schedule so that the estimated value of the soil moisture content does not exceed the growth inhibition moisture point.

[0110] There is a deviation between the growth inhibition moisture point and the upper target value. This upper deviation range is determined based on the climate of the field 20 while taking into consideration the healthy growth of the plant 30 described above. The climate of the field 20 includes the expected average rainfall amount of the field 20 during the irrigation period of the irrigation schedule and the total rainfall amount predicted by the weather forecast during the irrigation period. The expected average rainfall amount of the field 20 during the irrigation period is stored in the information storage unit 500.

[0111] There is a deviation between the permanent wilting point and the lower limit target value. This lower limit deviation width is determined based on the expected recovery time when a failure occurs in the water supply device 100 and the decrease in soil moisture content per unit time, while also taking into consideration the healthy growth of the plant 30. For example, the lower limit deviation width is determined based on the value obtained by multiplying the recovery time by the decrease in soil moisture content per unit time. The recovery time is stored in the information storage unit 500.

[0112] For example, when a one-week weather forecast is stored in the information storage unit 500 from the external information source 1000, the integrated calculation unit 600 determines an irrigation schedule for the one week. If the weather forecast does not predict any rainfall during this one-week period, the estimated soil moisture content is expected to gradually decrease over time. The decrease in the estimated soil moisture content per unit time is determined based on a predicted decrease in the soil moisture content of the plowed soil layer. For ease of notation, the estimated soil moisture content will be referred to simply as the estimated value below as necessary.

[0113] As described above, the watering schedule is determined based on the estimated soil moisture content based on environmental values ​​and the like, and on the weather forecast. This makes it possible to prevent the soil moisture content in the outdoor divided areas from becoming unsuitable for the plants 30 due to weather changes such as rainfall or dryness. It is also possible to prevent the soil moisture content from exceeding the growth inhibition moisture point or falling below the permanent wilting point.

[0114] The integrated calculation unit 600 determines the target water supply amount so that the estimated value of the soil moisture content does not exceed the upper limit target value lower than the growth inhibition moisture point during any irrigation period of the irrigation schedule. The integrated calculation unit 600 determines the deviation range (upper limit deviation range) between the growth inhibition moisture point and the upper limit target value based on the climate of the field 20, etc. The climate of the field 20 includes the expected average rainfall amount of the field 20 during the irrigation period and the total rainfall amount predicted by the weather forecast during the irrigation period. By setting the upper limit deviation range in this manner, even if there is more rainfall than predicted by the weather forecast after the soil moisture content is brought close to the upper limit target value by the supply of irrigation water, the soil moisture content is prevented from reaching the growth inhibition moisture point.

[0115] The integrated calculation unit 600 determines the target water supply amount so that the estimated value of the soil moisture content in the irrigation schedule does not fall below a lower limit target value higher than the permanent wilting point. The integrated calculation unit 600 determines the deviation width (lower limit deviation width) between the permanent wilting point and the lower limit target value based on the recovery time and the decrease in soil moisture content per unit time. By setting the lower limit deviation width in this manner, even if irrigation water cannot be supplied due to a malfunction of the water supply valve 152 when the soil moisture content is close to the lower limit target value, the soil moisture content can be prevented from reaching the permanent wilting point until the malfunction is restored.

[0116] The integrated calculation unit 600 supplies water at the time when the estimated soil moisture content in the irrigation schedule reaches the lower limit target value. This makes it possible to prevent the soil moisture content from falling below the lower limit target value. The integrated calculation unit 600 differentiates the rainfall forecast time from the time when irrigation water is supplied. This makes it possible to prevent the soil moisture content from increasing excessively even if the amount of rainfall is greater than the rainfall forecast.

[0117] An example of a valve device applicable to the water supply valve 152 will be described below with reference to Figures 13 to 15. This valve device is a so-called rotary type valve device. This valve device has one fluid inlet and three fluid outlets. This valve device is mounted on the irrigation system 10 by connecting the supply pipe 132 to the fluid inlet and connecting the distribution tube 136 to any one of the fluid outlets. Furthermore, a blocking member may be attached to the fluid outlet to which the distribution tube 136 is not connected, thereby blocking the passage.

[0118] 13, the valve device includes a housing 9, a valve 90, a drive unit 70, a drive unit cover 80, etc. The valve device is configured as a ball valve in which the valve 90 rotates about the axis of a shaft 92 to open and close the valve device. In this specification, the direction along the axis of the shaft 92 is referred to as the axial direction DRa, and the direction perpendicular to the axial direction DRa and extending radially from the axial direction DRa is referred to as the radial direction DRr.

[0119] The housing 9 is an accommodating section that accommodates the valve 90. The housing 9 is formed, for example, from a resin member. The housing 9 includes a hollow housing main body 21 that accommodates the valve 90, a pipe member 50 that causes cooling water to flow out from the housing main body 21, and a partition wall section 60 that is attached to the housing main body 21. The housing main body 21 has an approximately rectangular parallelepiped appearance and is formed into a bottomed shape with an opening on the other side in the axial direction DRa. The housing main body 21 has a housing outer wall section 22 that constitutes the outer periphery of the housing main body 21. The housing outer wall section 22 forms a cylindrical valve accommodating space 23 inside the housing main body 21, the valve accommodating space 23 having an axis in the axial direction DRa.

[0120] An inlet port 251 for allowing cooling water to flow into the valve accommodating space 23 is formed in the housing outer wall portion 22. The inlet port 251 is formed with a circular opening, and is connected to the connecting pipe 135. The inlet port 251 corresponds to a fluid inlet portion.

[0121] A pipe member 50 is attached to the housing outer wall portion 22. The housing outer wall portion 22 has a first outlet port 261, a second outlet port 262, and a third outlet port 263 for allowing the cooling water that has flowed into the valve accommodating space 23 via the inlet port 251 to flow out to the pipe member 50. The first outlet port 261, the second outlet port 262, and the third outlet port 263 correspond to a fluid outflow portion.

[0122] A partition wall portion 60 is attached to the housing opening surface 24 of the housing outer wall portion 22. The housing opening surface 24 is disposed on the other side of the housing main body portion 21 in the axial direction DRa. The housing opening surface 24 has a housing opening 241 that communicates between the valve accommodating space 23 and the outside of the housing main body portion 21. The housing opening 241 is closed by attaching the partition wall portion 60 to the housing opening surface 24.

[0123] The pipe member 50 includes a first pipe section 51, a second pipe section 52, and a third pipe section 53, each of which is formed into a cylindrical shape. The first pipe section 51, the second pipe section 52, and the third pipe section 53 are connected by a pipe connecting section 54. The pipe connecting section 54 connects the first pipe section 51, the second pipe section 52, and the third pipe section 53, and is a section for attaching the pipe member 50 to the housing outer wall section 22. The first pipe section 51 has an upstream side disposed inside the first outlet port 261. The second pipe section 52 has an upstream side disposed inside the second outlet port 262. The third pipe section 53 has an upstream side disposed inside the third outlet port 263.

[0124] The partition portion 60 closes the housing opening 241 and holds the valve 90 accommodated in the valve accommodating space 23. The partition portion 60 is disk-shaped with the axial direction DRa being the plate thickness direction, and is arranged so as to be fitted into the housing opening 241 from the other side toward one side in the axial direction DRa. When the partition portion 60 is fitted into the housing opening 241, the outer periphery of the partition portion 60 abuts against the inner circumferential surface of the housing, thereby closing the housing opening 241.

[0125] The drive unit cover 80 houses the drive unit 70. The drive unit cover 80 is made of resin and has a hollow shape, and a drive unit space for housing the drive unit 70 is formed inside. The drive unit cover 80 has a connector section 81 for connecting to the microcomputer 330. The connector section 81 connects the valve device to the microcomputer 330, and has built-in terminals to which the drive unit 70 and the rotation angle sensor 73 are connected.

[0126] The drive unit 70 includes a motor 71 that outputs a rotational force for rotating the valve 90, a gear unit 72 that transmits the output of the motor 71 to the valve 90, and a rotation angle sensor 73 that detects the rotation angle of the gear unit 72. As shown in FIG. 14, the motor 71 includes a motor body, a motor shaft 711, a worm gear 712, and a motor side terminal. The motor 71 is configured so that the motor body can output power when power is supplied to the motor side terminal. The motor body is formed in a substantially cylindrical shape, and the motor shaft 711 protrudes from the other end of the motor body. The power output from the motor body is output to the gear unit 72 via the motor shaft 711 and the worm gear 712.

[0127] The gear portion 72 is composed of a reduction mechanism having a plurality of resin gears, and is configured to be able to transmit the power output from the worm gear 712 to the shaft 92. The gear portion 72 includes a first gear 721, a second gear 722 meshing with the first gear 721, and a third gear 723 meshing with the second gear 722. The shaft 92 is connected to the third gear 723. In the gear portion 72, the outer diameter of the second gear 722 is formed to be larger than the outer diameter of the first gear 721, and the outer diameter of the third gear 723 is formed to be larger than the outer diameter of the second gear 722.

[0128] The first gear 721, the second gear 722, and the third gear 723 are arranged so that their respective axes are perpendicular to the axis of the worm gear 712. The third gear 723 is arranged so that its axis is coaxial with the axis of the shaft 92. The third gear 723 is connected to the shaft 92. The drive unit 70 is configured so that the worm gear 712, the first gear 721, the second gear 722, and the third gear 723 rotate integrally with the valve 90, and the rotations of each are correlated with each other. The rotation angles of these gears and the shaft 92 are correlated with each other, and the rotation angle of any one of the components having the correlation can be calculated from the rotation angle of the other components.

[0129] A rotation angle sensor 73 for detecting the rotation angle of the third gear 723 is attached to the inner periphery of the drive unit cover 80 at a position facing the third gear 723. The rotation angle sensor 73 is a Hall type sensor with a built-in Hall element, and is configured to be able to detect the rotation angle of the third gear 723 in a non-contact manner. The rotation angle sensor 73 is connected to the microcomputer 330 via a connector unit 81. The detected rotation angle of the third gear 723 is transmitted to the microcomputer 330. A processing unit 334 of the microcomputer 330 is configured to be able to calculate the rotation angle of the valve 90 based on the rotation angle of the third gear 723 transmitted from the rotation angle sensor 73.

[0130] The shaft 92 and the valve 90 will be described with reference to Figs. 13 and 15. The shaft 92 is configured to be rotatable about its axis by the rotational force output by the drive unit 70. The valve 90 is connected to the shaft 92, and is configured to be able to rotate the valve 90 integrally with the shaft 92 when the shaft 92 rotates. The shaft 92 is formed to extend in a cylindrical shape along the axis, and penetrates the valve 90 from one side to the other side. One side of the shaft 92 in the axial direction DRa is connected to the shaft support part of the housing main body 21, and the other side is connected to the gear part 72. The valve 90 is fixed to the outer periphery of the shaft.

[0131] The valve 90 is configured to be able to adjust the flow rate of the output fluid by rotating around the axis. The valve 90 has a shaft 92 inserted therein and is accommodated in the valve accommodation space 23 so as to be able to rotate together with the shaft 92. The valve 90 is cylindrical with an axis extending along the axial direction DRa. The valve 90 is formed by connecting a first valve 93, a second valve 94, and a third valve 95, each of which is cylindrical, a cylindrical connection part 914, and a cylindrical valve connection part 915. The valve 90 is arranged such that the first valve 93, the cylindrical connection part 914, the second valve 94, the cylindrical valve connection part 915, and the third valve 95 are arranged in this order from one side to the other side of the axial direction DRa. The first valve 93 and the second valve 94 are connected via the cylindrical connection part 914. The second valve 94 and the third valve 95 are connected via the cylindrical valve connection part 915.

[0132] In the valve accommodating space 23, the second valve 94 and the cylindrical connection portion 914 of the valve 90 face the inlet port 251 in the radial direction DRr. The valve 90 has a cylindrical shaft connection portion 916 in the center into which the shaft 92 is inserted. The valve 90 is connected to the shaft 92 by inserting the shaft 92 into the shaft connection portion 916. In the valve 90, for example, the first valve 93, the second valve 94, the third valve 95, the cylindrical connection portion 914, the cylindrical valve connection portion 915, and the shaft connection portion 916 are integrally molded by injection molding.

[0133] The valve 90 is a valve body for allowing the cooling water that has flowed into the valve 90 to flow out to a first outlet port 261, a second outlet port 262, and a third outlet port 263. When the valve 90 rotates, the first valve 93 opens and closes the first outlet port 261, the second valve 94 opens and closes the second outlet port 262, and the third valve 95 opens and closes the third outlet port 263.

[0134] The first valve 93, the second valve 94, and the third valve 95 are arranged so that their respective axes are coaxial with the axis of the shaft 92. The first valve 93, the second valve 94, and the third valve 95 each have a central portion in the axial direction DRa that bulges outward in the radial direction DRr compared to both end sides. The first valve 93, the second valve 94, and the third valve 95 each are configured to allow fluid to flow inside.

[0135] 15, the first valve 93 has a first valve outer periphery 931 that forms an outer periphery, and a first flow path portion 961 is formed inside the first valve outer periphery 931. The first valve 93 is formed with a first inner opening 936 that allows fluid to flow into the first flow path portion 961. In the first valve 93, the fluid that has flowed into the valve accommodating space 23 flows into the first flow path portion 961 via the first inner opening 936. The first flow path portion 961 corresponds to a flow path portion in a valve device.

[0136] As shown in FIG. 15, the first valve outer periphery 931 is formed with a first outer periphery opening 934 that communicates the first flow passage 961 with the first outlet port 261 via the first seal opening 581 when the shaft 92 rotates. The first valve 93 allows the fluid that has flowed into the first flow passage 961 to flow out from the first outlet port 261 by communicating the first outer periphery opening 934 with the first outlet port 261. The first outer periphery opening 934 formed in the first valve outer periphery 931 corresponds to an outer periphery opening formed in the valve outer periphery. The first outer periphery opening 934 is formed in the first valve outer periphery 931, extending in the circumferential direction of the axis of the shaft 92. The flow rate of the fluid flowing out of the device from the first valve 93 is adjusted according to the area of ​​overlap between the first outer periphery opening 934 and the first seal opening 581 when the shaft 92 rotates. The first inner opening 936 functions as a communication passage that connects the outside of the first valve 93 with the first flow path portion 961 .

[0137] 15, the second valve 94 has a second valve outer periphery 941 forming an outer periphery, and a second flow path portion 962 is formed inside the second valve outer periphery 941. The second valve 94 is formed with a second inner opening 946 that allows the fluid to flow into the second flow path portion 962 on one side in the axial direction DRa. The second valve 94 is configured so that the fluid that flows into the valve accommodating space 23 via the inlet port 251 can flow through the second flow path portion 962 via the second inner opening 946. The second flow path portion 962 corresponds to a flow path portion in a valve device.

[0138] 15, a second outer circumferential opening 944 is formed in the second valve outer circumferential portion 941, which communicates the second flow path portion 962 with the second outlet port 262 via the second seal opening 582 when the shaft 92 rotates. The second valve 94 allows the fluid that has flowed into the second flow path portion 962 to flow out from the second outlet port 262 by communicating the second outer circumferential opening 944 with the second outlet port 262. The second outer circumferential opening 944 formed in the second valve outer circumferential portion 941 corresponds to the outer circumferential opening formed in the valve outer circumferential portion.

[0139] The second outer periphery opening 944 is formed to extend in the circumferential direction of the axis of the shaft 92. The flow rate of the fluid flowing out from the second valve 94 to the outside of the device is adjusted according to the area of ​​overlap between the second outer periphery opening 944 and the second seal opening 582 when the shaft 92 rotates. The second inner opening 946 functions as a communication passage that communicates the outside of the second valve 94 with the second flow path portion 962. The second inner opening 946 faces the first inner opening 936. The cylindrical connection portion 914 is for connecting the first valve 93 and the second valve 94. The cylindrical connection portion 914 forms a first inter-valve space 97 between the outer periphery of the cylindrical connection portion 914 and the inner periphery of the housing. The first flow path portion 961 and the second flow path portion 962 communicate with each other via the first inter-valve space 97.

[0140] The second valve 94 has a shaft connection part 916 disposed in approximately the center inside, the shaft connection part 916 covering the outer periphery of the shaft 92. The second valve 94 has a cylindrical valve connection part 915 connected to the other side in the axial direction DRa of the second valve outer periphery 941. The second valve 94 is configured to allow the fluid that has flowed into the second flow path part 962 to flow into the third valve 95 via the cylindrical valve connection part 915.

[0141] The cylindrical valve connection part 915 has a second inter-valve space 98 formed on the inside. The second inter-valve space 98 is in communication with the second flow path part 962 and the third flow path part 963. The cylindrical valve connection part 915 has an outer diameter on one side in the axial direction DRa that is the same as the outer diameter of the portion of the second valve 94 on the other side in the axial direction DRa. The cylindrical valve connection part 915 has an outer diameter on the other side in the axial direction DRa that is the same as the outer diameter of the portion of the third valve 95 on one side in the axial direction DRa. The cylindrical valve connection part 915 is formed to be continuous with the second valve outer periphery part 941 and the third valve outer periphery part 951.

[0142] 15, the third valve 95 has a third valve outer periphery 951 that forms the outer periphery of the third valve 95, and a third flow path portion 963 is formed inside the third valve outer periphery 951. One side of the third valve outer periphery 951 in the axial direction DRa of the third valve 95 is connected to the cylindrical valve connection portion 915. In the third valve 95, the fluid that has flowed into the second flow path portion 962 flows into the third flow path portion 963 via the second inter-valve space 98. The third flow path portion 963 corresponds to a flow path portion in a valve device.

[0143] 15, a third outer periphery opening 954 is formed in the third valve outer periphery portion 951, which connects the third flow path portion 963 to the third outlet port 263 via the third seal opening 583 when the shaft 92 rotates. The third valve 95 allows the fluid that has flowed into the third flow path portion 963 to flow out of the device from the third outlet port 263 by connecting the third outer periphery opening 954 to the third outlet port 263. The third outer periphery opening 954 formed in the third valve outer periphery portion 951 corresponds to the outer periphery opening formed in the valve outer periphery.

[0144] The third outer periphery opening 954 is formed in the third valve outer periphery 951, extending in the circumferential direction of the axis. The flow rate of the fluid flowing out from the third valve 95 to the outside of the device is adjusted according to the area of ​​overlap between the third outer periphery opening 954 and the third seal opening 583 when the shaft 92 rotates. The shaft connection part 916 is cylindrical, and connects the valve 90 and the shaft 92 by fixing the inserted shaft 92. When the shaft 92 rotates, the shaft connection part 916 transmits the rotational force of the shaft 92 to the valve 90 via the shaft connection part 916. The shaft connection part 916 is formed extending from the second valve 94 to the third valve 95 toward the other side of the axial direction DRa.

[0145] The operation of the water supply valve 152 will be described. The microcomputer 330 calculates the rotation angle of the valve 90 for supplying the necessary flow rate of water to the distribution tube 136, i.e., the rotation angle of the motor 71. The microcomputer 330 transmits information on the calculated rotation angle of the motor 71 to the water supply valve 152. At this time, blocking members are attached to the two fluid outlets that are not connected to the distribution tube 136.

[0146] The water supply valve 152 rotates the motor 71 based on the information on the rotation angle received from the microcomputer 330. By rotating the motor 71, the water supply valve 152 rotates the valve 90 via the gear portion 72 and the shaft 92, and causes a required flow rate of fluid to flow out from the first outer circumferential opening 934, the second outer circumferential opening 944, and the third outer circumferential opening 954.

[0147] For example, a case where the first outlet port 261 is adopted as a fluid outflow portion that communicates with the distribution tube 136 will be described. The water supply valve 152 communicates the first outer periphery opening 934 of the first valve 93 with the first outlet port 261 by rotating the valve 90. The water supply valve 152 adjusts the overlapping area between the first outer periphery opening 934 and the first seal opening 581 by adjusting the rotational position of the valve 90. The water supply valve 152 causes the fluid that has flowed into the valve accommodating space 23 from the inlet port 251 to flow into the first flow path portion 961 via the first inner opening 936, and causes the fluid to flow out from the first outer periphery opening 934 to the first outlet port 261. The microcomputer 330 controls the valve opening, which is the overlapping area between the first outer periphery opening 934 and the first seal opening 581, to control the water jump distance of the irrigation water and supply the irrigation water to a required position.

[0148] For example, a case where the second outlet port 262 is adopted as a fluid outflow portion that communicates with the distribution tube 136 will be described. The water supply valve 152 communicates the second outer periphery opening 944 of the second valve 94 with the second outlet port 262 by rotating the valve 90. The water supply valve 152 adjusts the overlapping area between the second outer periphery opening 944 and the second seal opening 582 by adjusting the rotational position of the valve 90. The water supply valve 152 causes the fluid that has flowed into the valve accommodating space 23 from the inlet port 251 to flow into the second flow passage portion 962 via the second inner opening 946, and causes the fluid to flow out from the second outer periphery opening 944 to the second outlet port 262. The microcomputer 330 controls the valve opening, which is the overlapping area between the second outer periphery opening 944 and the second seal opening 582, to control the water jump distance of the irrigation water and supply the irrigation water to a required position.

[0149] For example, a case where the third outlet port 263 is adopted as a fluid outflow portion that communicates with the distribution tube 136 will be described. The water supply valve 152 communicates the third outer periphery opening 954 of the third valve 95 with the third outlet port 263 by rotating the valve 90. The water supply valve 152 adjusts the overlapping area between the third outer periphery opening 954 and the third seal opening 583 by adjusting the rotational position of the valve 90. The water supply valve 152 causes the fluid that has flowed into the valve accommodating space 23 from the inlet port 251 to flow into the third flow path portion 963 via the second flow path portion 962 of the second valve 94, and causes the fluid to flow out from the third outer periphery opening 954 to the third outlet port 263. The microcomputer 330 controls the valve opening, which is the overlapping area between the third outer periphery opening 954 and the third seal opening 583, to control the water jump distance of the irrigation water and supply the irrigation water to a required position.

[0150] In the water supply valve 152 , the rotation angle sensor 73 detects the rotation angle of the third gear 723 , and feeds back information on the detected rotation angle to the microcomputer 330 , thereby adjusting the rotation angle of the motor 71 .

[0151] The relationship between the rotation angle of the shaft 92 and the flow rate of the valve device will be described with reference to the graph of FIG. 16. In FIG. 16, the horizontal axis represents the rotation angle RA of the motor 71, and the vertical axis represents the flow rate FR of the fluid flowing out of the valve device. In FIG. 16, FO1 is the first valve 93, FO2 is the second valve 94, and FO3 is the third valve 95. In FIG. 16, FS indicates that the valve opening is fully open, FC indicates that the valve opening is fully closed, and MO indicates that the valve opening is intermediate. The intermediate opening is an opening between the fully closed state and the fully open state. The solid line graph in FIG. 16 shows the relationship between the flow rate of the fluid flowing out of the third valve 95 and the rotation angle. The dashed line graph in FIG. 16 shows the relationship between the flow rate of the fluid flowing out of the second valve 94 and the rotation angle. The dashed line graph in FIG. 16 shows the relationship between the flow rate of the fluid flowing out of the first valve 93 and the rotation angle.

[0152] 16, when the rotation angle is near 0 degrees, third valve 95 is fully open and the other valves are fully closed, and fluid flows out of the device only through third valve 95. When the rotation angle is increased from this state, third valve 95 transitions to an intermediate opening, and when the rotation angle is further increased, all three valves are fully closed.

[0153] When the rotation angle of all three valves is increased from a fully closed state, only the second valve 94 transitions to a fully open state via an intermediate opening. When the rotation angle is further increased, the first valve 93 transitions to a fully open state via an intermediate opening, and the first valve 93 and the second valve 94 are in a fully open state. When the rotation angle is increased from this state, the second valve 94 transitions to a fully closed state via an intermediate opening, and the second valve 94 and the third valve 95 are in a fully closed state. When the rotation angle is further increased, the first valve 93 transitions to a fully closed state via an intermediate opening, and all valves are in a fully closed state.

[0154] As described above, the opening degree of each valve changes according to the rotation angle, and the flow rate of fluid flowing out from each valve changes. Each water supply valve 152 in the irrigation system 10 is configured to supply fluid from only one of the three valves, thereby controlling the distance that water splashes into the field 20 and the amount of water supplied according to the rotation angle.

[0155] Next, an example of the passage configuration and components related to water supply control provided in the irrigation system 10 will be described with reference to Figs. 17 and 18. Fig. 17 shows an example of the positional relationship between the distribution tube 136, the water supply valve 152, and the water pressure sensor 153. The vertical pipe 133 is connected to a plurality of passages leading to a plurality of distribution tubes 136. Each of the plurality of passages connects the distribution tube 136 and the vertical pipe 133. A water supply valve 152 and a water pressure sensor 153a or a flow rate sensor 154a are provided in the passage between each distribution tube 136 and the vertical pipe 133. The water pressure sensor 153a or the flow rate sensor 154a is provided downstream of the water supply valve 152. The water pressure sensor 153a and the flow rate sensor 154a detect water supply information related to the water supply in the upstream passage flowing down toward the through hole of the distribution tube 136. The signal output unit 332 outputs a control signal to the water supply valve for controlling the valve opening degree by feedback control using the water supply information detected in the upstream passage.

[0156] The vertical pipe 133 is connected to a passage leading to the inlet port 251 of each water supply valve 152. Each distribution tube 136 is connected to a passage leading to the first pipe section 51, which is one of the fluid outlet sections of each water supply valve 152. In this case, the second pipe section 52 and the third pipe section 53, which are the other fluid outlet sections, are blocked by a blocking member. In addition, the water pressure sensor 153b or the flow rate sensor 154b may be configured to be provided further downstream than the through hole located at the most downstream position in the distribution tube 136. The water pressure sensor 153b and the flow rate sensor 154b detect water supply information related to water supply at the downstream end of the distribution tube 136. The signal output unit 332 outputs a control signal to the water supply valve for controlling the valve opening by feedback control using the water supply information detected at the downstream end. The signal output unit 332 outputs a control signal to the water supply valve for controlling the valve opening by feedback control using the water supply information detected at the upstream passage and the downstream end.

[0157] The distribution tube 136 of the irrigation system 10 is configured to expand and contract in response to the water pressure flowing therethrough. The distribution tube 136 is formed, for example, of a material and hardness that can elastically deform in response to water pressure. FIG. 18 is a diagram for explaining the relationship between the expansion of the distribution tube 136 and the internal pressure. The diagram (a) shows a tube cross section when the valve opening of the water supply valve 152 is fully closed. In this state, the tube is not filled with water, the internal pressure is almost zero, and the tube has a flat shape that is not inflated. The diagram (c) shows a tube cross section in which the valve opening of the water supply valve 152 is fully open and the tube is fully expanded by the internal pressure. In this state, the tube does not expand or contract while water is being discharged from the tube, and the amount of water discharged from the downstream part of the tube is less than that from the upstream part due to the water flow pressure loss. Therefore, the amount of water discharged from the tube varies in the extension direction of the tube.

[0158] The diagram (b) in FIG. 18 shows a cross section of the tube controlled to an internal pressure between the states (a) and (c). In this state, the tube is not fully expanded and can expand and contract with slight changes in internal pressure. For this reason, the tube itself functions as a diaphragm due to changes in internal pressure of the water passing through it, so there is little difference in the amount of water discharged from the downstream and upstream parts of the tube. Therefore, the amount of water discharged from the tube is almost uniform over the entire length of the tube. The valve opening of the water supply valve 152 is controlled using the detection value of the water pressure sensor 153 etc. so that the internal pressure during irrigation is such that the tube can expand and contract as shown in (c).

[0159] The water pressure detected by the water pressure sensor 153a and the water pressure sensor 153b is output to the microcomputer 330 of the monitoring unit 300. The microcomputer 330 feedback-controls the valve opening of each water supply valve 152 to a target opening using the water pressure detected by the water pressure sensor 153a and the water pressure sensor 153b. The microcomputer 330 feedback-controls the valve opening of each water supply valve 152 to a target opening using the flow rate detected by the flow rate sensor 154a and the flow rate sensor 154b. The irrigation system 10 individually controls the valve opening of each water supply valve 152 to individually control the water discharge amount and water flight distance from the corresponding distribution tube 136. By such control, the microcomputer 330 can perform irrigation that satisfies the target water discharge amount even if the flow rate and pressure of each distribution tube change due to the elevation difference of the field 20, fluctuations in the water supply source pressure, fluctuations in the irrigation distribution amount from the vertical pipe 133 to the distribution tube, etc.

[0160] The processing unit 334 determines the valve opening of the water supply valve that controls the pressure of the irrigation water flowing down to the distribution tube 136 that does not have a pressure correction mechanism, upstream of the distribution tube. The signal output unit 332 outputs a control signal to the water supply valve to control the valve opening in order to control the amount of irrigation water discharged from the distribution tube through the through hole. The signal output unit 332 controls the current supply time required to control the valve opening to the target opening in units of subdivided times (subdivision amounts) subdivided into multiple stages, thereby controlling the valve opening to the target opening in stages. The signal output unit 332 controls the current supply amount (subdivision amount) required to control the valve opening to the target opening in units of subdivided current supply amounts subdivided into multiple stages, thereby controlling the valve opening to the target opening in stages. In this way, the microcomputer 330 controls the valve opening of the water supply valve 152 to gradually increase or decrease it, rather than opening or closing it abruptly. With this control, the water supply valve 152 can suppress abrupt pressure changes and prevent malfunctions caused by pressure changes. This control contributes to suppressing damage to passage components due to, for example, water hammer.

[0161] The irrigation system 10 of the first embodiment includes a distribution tube 136 having a plurality of through holes for sprinkling irrigation water on a farm field 20 and having no pressure compensation mechanism. The irrigation system 10 includes a water supply valve 152 that controls the pressure of the water flowing down toward the distribution tube 136 upstream of the distribution tube 136. The irrigation system 10 includes a control device that controls the valve opening of the water supply valve 152 to control the amount of irrigation water discharged from the distribution tube 136 through the through holes. According to the irrigation system 10, the valve opening of the water supply valve 152 is controlled upstream of the distribution tube 136 that does not have a pressure compensation mechanism to control the amount of irrigation water. The irrigation system 10 can perform irrigation in which the amount of irrigation water is changed sequentially by controlling this valve opening. Therefore, both drip irrigation and sprinkling irrigation can be performed from the distribution tube 136.

[0162] The irrigation system 10 includes a water pressure sensor or a flow rate sensor that detects water supply information at the upstream passage or downstream end of the distribution tube that flows down toward the through hole of the distribution tube. The control device controls the valve opening of the water supply valve by feedback control using the detected water supply information. This allows the valve opening to be adjusted continuously using water pressure information or flow rate information detected at the upstream passage or downstream end of the distribution tube to continuously control the water discharge amount. Therefore, the irrigation system 10 can steadily control the water discharge amount to a target amount according to the weather, soil conditions, crop growth conditions, etc.

[0163] The water pressure sensor or flow rate sensor detects water supply information at the upstream passage and the downstream end. The control device controls the valve opening by feedback control using the water supply information detected at the upstream passage and the downstream end. This allows the valve opening to be continuously adjusted using water pressure information or flow rate information detected at the upstream passage and the downstream end for the distribution tube. The irrigation system 10 can perform valve opening control that suppresses variation in water discharge volume throughout the entire length of the distribution tube by controlling the water supply information at the upstream passage and the downstream end.

[0164] The control device controls the valve opening of the water supply valve 152 within the range of water pressure at which the distribution tube 136 expands and contracts. This controls the valve opening of the water supply valve so that the pressure is lower than the pressure at which the distribution tube is fully inflated. As a result, the tube itself acts as a diaphragm valve, providing a stable water discharge rate all the way to the downstream end of the distribution tube. This makes it possible to achieve irrigation with reduced difference in water discharge rate between the downstream and upstream parts of the tube.

[0165] The output unit outputs a control signal to the water supply valve to control the valve opening within the range of water pressure at which the distribution tube, which is configured to expand and contract according to the water pressure flowing inside, expands and contracts. This control device controls the valve opening of the water supply valve so as to control the pressure to a level lower than that at which the distribution tube is fully inflated. With this control, the tube itself acts as a diaphragm valve, providing a stable water discharge volume all the way to the downstream end of the distribution tube.

[0166] <Second embodiment> The second embodiment will be described with reference to Figures 19 and 20. The irrigation system 10 of the second embodiment has the passage configuration and components related to water supply control as shown in Figure 19. The configurations, actions, and effects of the second embodiment that are not specifically described are the same as those of the previously described embodiments, and only the differences will be described below.

[0167] FIG. 19 shows an example of the positional relationship between the distribution tube 137, the water supply valve 152, and the water pressure sensor 153. The passage configuration shown in FIG. 19 differs from the configuration shown in FIG. 17 in the configuration of the distribution tube 137 that discharges irrigation water. The distribution tube 137 is arranged in a U-shape in the field 20. The irrigation system 10 of the second embodiment includes a plurality of distribution tubes 137 connected to a vertical pipe 133 through which the water supply from the pump 110 flows. The distribution tube 137 has a first distribution section 137a, a second distribution section 137b, and a folded section that connects the first distribution section 137a and the second distribution section 137b. The first distribution section 137a and the second distribution section 137b have a shape that extends in the same direction, for example, in the x direction, and are arranged in the y direction at a predetermined interval.

[0168] The distribution tube 137 does not have a pressure compensation mechanism that realizes a constant water discharge amount regardless of the change in water pressure. The water discharge amount from the through hole of the distribution tube 137 is adapted to change according to the water pressure. The distribution tube 137 is configured to expand and contract according to the water pressure flowing inside, similar to the distribution tube 136 of the first embodiment. The distribution tube 137 is formed, for example, with a material and hardness that can be elastically deformed according to the water pressure. Each tube part of the first distribution part 137a and the second distribution part 137b is formed with a plurality of through holes that communicate the inside and outside of each distribution part through which the irrigation flows. The plurality of through holes are arranged in each distribution part at a predetermined interval in the axial direction of the tube. Also, the through holes may be arranged in each distribution part at a predetermined interval in the circumferential direction of the tube.

[0169] The vertical pipe 133 is connected to a plurality of passages leading to a plurality of distribution tubes 137. Each of the plurality of passages connects the first distribution section 137a and the second distribution section 137b to the vertical pipe 133. A water supply valve 152, and a water pressure sensor 153a or a flow rate sensor 154a are provided in the passage between the first distribution section 137a and the vertical pipe 133. A water supply valve 152, and a water pressure sensor 153a or a flow rate sensor 154a are provided in the passage between the second distribution section 137b and the vertical pipe 133.

[0170] Two water pressure sensors 153a located at both ends of the distribution tube 137 detect water supply information related to the water supply in the upstream passage where the water flows down toward the through hole of the distribution tube. The two water pressure sensors 153a also detect water supply information related to the water supply at the downstream end of the distribution tube. The two water pressure sensors 153a may be replaced with two flow rate sensors 154a. Each of the first distribution section 137a and the second distribution section 137b is connected to a passage leading to the first pipe section 51, which is one of the fluid outlet sections of the water supply valve 152. The irrigation system 10 individually controls the valve opening for each water supply valve 152, thereby individually controlling the water discharge amount and water flight distance from the corresponding distribution tube 137.

[0171] In the irrigation of the distribution tube 137, the irrigation system 10 can supply water from either the first distribution section 137a side or the second distribution section 137b side. When water is discharged from the first distribution section 137a, the microcomputer 330 controls the valve aperture of the water supply valve 152 located between the first distribution section 137a and the vertical pipe 133 to an open state. When water is discharged from the second distribution section 137b, the microcomputer 330 controls the valve aperture of the water supply valve 152 located between the second distribution section 137b and the vertical pipe 133 to an open state.

[0172] When water is discharged only from the first distribution section 137a, the microcomputer 330 controls the valve on the first distribution section 137a side to open and the valve on the second distribution section 137b side to close. With this control, the irrigation water supplied from the first distribution section 137a side is discharged from the through hole of the first distribution section 137a, flows down the turn-back section and is discharged from the through hole of the second distribution section 137b. When water is discharged only from the second distribution section 137b, the microcomputer 330 controls the valve on the second distribution section 137b side to open and the valve on the first distribution section 137a side to close. With this control, the irrigation water supplied from the second distribution section 137b side is discharged from the through hole of the second distribution section 137b, flows down the turn-back section and is discharged from the through hole of the first distribution section 137a.

[0173] FIG. 20 is a diagram for explaining the relationship between the water discharge position in distribution tube 137 and the amount of irrigation water. In FIG. 20, the horizontal axis represents the position of the through hole in distribution tube 137, and the vertical axis represents the amount of irrigation water. Water discharge position P1 is the position of the through hole closest to water supply valve 152 in first distribution section 137a. Water discharge position P2 is the position of the through hole closest to the turn-back portion in first distribution section 137a. Water discharge position P3 is the position of the through hole closest to the turn-back portion in second distribution section 137b. Water discharge position P4 is the position of the through hole closest to water supply valve 152 in second distribution section 137b.

[0174] The dashed line graph in Fig. 20 shows irrigation in which the water supply valve 152 on the first distribution section 137a side is controlled to an open state and the water supply valve 152 on the second distribution section 137b side is controlled to a closed state. In other words, the dashed line graph in Fig. 20 shows the relationship between the water discharge position and the amount of irrigation water in irrigation in which water is supplied only from the water supply valve 152 on the first distribution section 137a side. According to the dashed line graph, the amount of irrigation water is greatest at water discharge position P1, water discharge position P2, water discharge position P3, and water discharge position P4 in that order, and decreases the farther from the water supply valve 152 due to water flow resistance.

[0175] The dashed-dotted line graph in Fig. 20 shows irrigation in which the water supply valve 152 on the first distribution section 137a side is controlled to a closed state and the water supply valve 152 on the second distribution section 137b side is controlled to an open state. In other words, the dashed-dotted line graph in Fig. 20 shows the relationship between the water discharge position and the amount of irrigation water in irrigation in which water is supplied only from the water supply valve 152 on the second distribution section 137b side. According to the dashed-dotted line graph, the amount of irrigation water is greatest at water discharge position P4, water discharge position P3, water discharge position P2, and water discharge position P1 in that order, and decreases the farther away from the water supply valve 152 due to water flow resistance.

[0176] The solid line graph in Fig. 20 shows the total amount of irrigation water combined with the dashed line graph and the dashed line graph. In other words, the solid line graph in Fig. 20 shows the total amount of irrigation water from the first distribution unit 137a side and the second distribution unit 137b side. The variation in the amount of irrigation water in the solid line graph is smaller than the difference in the amount of irrigation water between the upstream and downstream in the dashed line graph and the difference in the amount of irrigation water between the upstream and downstream in the dashed line graph. The irrigation system 10 can suppress the variation in the amount of irrigation water due to the water discharge position by irrigation control that switches between irrigation water from the first distribution unit 137a side and irrigation water from the second distribution unit 137b side.

[0177] The effects of the irrigation system 10 of the second embodiment will be described. The distribution tube 137 has a first distribution section 137a and a second distribution section 137b, each of which has a plurality of through holes, and a folded section connecting the first distribution section and the second distribution section. The second distribution section 137b extends along the first distribution section 137a and is aligned with the first distribution section at a distance. The water supply valve 152 controls the pressure of the water flowing down toward the end of each of the first distribution section and the second distribution section opposite the folded section.

[0178] According to this, irrigation can be performed by flowing down from the first distribution section to the second distribution section by closing the water supply valve on the second distribution section side and controlling the opening of the water supply valve on the first distribution section side. Furthermore, irrigation can be performed by flowing down from the second distribution section to the first distribution section by closing the water supply valve on the first distribution section side and controlling the opening of the water supply valve on the second distribution section side. The control device can control switching between these two irrigation. By this switching irrigation control, the irrigation system 10 can suppress variation in the discharge water volume due to tube pressure loss in the U-shaped distribution tube.

[0179] <Third embodiment> The third embodiment will be described with reference to Fig. 21. The irrigation system 10 of the third embodiment has the passage configuration and components related to water supply control as shown in Fig. 21. The configurations, actions, and effects of the third embodiment that are not specifically described are the same as those of the above-mentioned embodiments, and only the differences will be described below.

[0180] FIG. 21 shows an example of the positional relationship between the distribution tubes 136 and the water supply valves 152. A predetermined number of distribution tubes 136 arranged in the field 20 are connected downstream to a passage in which one water supply valve 152 is installed. In the third embodiment, the predetermined number is, for example, two or three. A plurality of passages communicating with a predetermined number of distribution tubes 136 and one water supply valve 152 are connected to the vertical pipe 133. Each of the plurality of passages connects the predetermined number of distribution tubes 136 and one water supply valve 152 to the vertical pipe 133. A plurality of groups forming irrigation passages each having a predetermined number of distribution tubes 136 and one water supply valve 152 are arranged in the field 20 at predetermined intervals in the y direction.

[0181] Each water supply valve 152 in this embodiment is connected to the vertical pipe 133 by one fluid inlet and to three distribution tubes 136 by three fluid outlets. Each distribution tube 136 is connected to a fluid outlet in the water supply valve 152. The water pressure sensor 153a or the flow rate sensor 154a is provided in a passage downstream of the water supply valve 152, between the fluid outlet of the water supply valve 152 and the distribution tube 136. The first pipe section 51 of the water supply valve 152 is connected to the distribution tube 136. The second pipe section 52 of the water supply valve 152 is connected to the distribution tube 136. The third pipe section 53 of the water supply valve 152 is connected to the distribution tube 136. The irrigation system 10 can individually control irrigation from a predetermined number of distribution tubes 136 connected to the water supply valve 152 by individually controlling the valve opening degree for each water supply valve 152.

[0182] The irrigation system 10 of the third embodiment includes one water supply valve 152 provided in an upstream passage so as to communicate with a predetermined number of distribution tubes 136. This allows the number of flow rate adjustment valves to be reduced in a system capable of performing both drip irrigation and sprinkler irrigation from the distribution tubes, thereby suppressing component and control costs.

[0183] <Fourth embodiment> The fourth embodiment will be described with reference to Fig. 22. The irrigation system 10 of the fourth embodiment has the passage configuration and components related to water supply control as shown in Fig. 22. The configurations, actions, and effects of the fourth embodiment that are not specifically described are the same as those of the previously described embodiments, and only the differences will be described below.

[0184] 22 shows an example of the positional relationship between the distribution tube 136 and the water supply valve 152. The irrigation system 10 of the fourth embodiment differs from the third embodiment in that it has a joint member 138 that connects the water supply valve 152 and multiple distribution tubes 136. The joint member 138 is a connecting member that connects one of the fluid outlet portions of the water supply valve 152 and a predetermined number of distribution tubes 136. In the fourth embodiment, the predetermined number is two or more.

[0185] A plurality of passages are connected to the vertical pipe 133, the passages communicating with one water supply valve 152, a plurality of joint members 138, and a predetermined number of distribution tubes 136 connected to each joint member 138. Each of the passages connects the vertical pipe 133 to the distribution tubes 136, the joint members 138, and one water supply valve 152. A plurality of groups each forming an irrigation passage having the distribution tubes 136, the joint members 138, and one water supply valve 152 are arranged in the y direction at predetermined intervals in the field 20. The number of distribution tubes 136 communicating with one water supply valve 152 is the number obtained by multiplying the number of joint members 138 connected to each water supply valve 152 by a predetermined number.

[0186] Each water supply valve 152 is connected to the vertical pipe 133 by one fluid inlet and to the multiple distribution tubes 136 via multiple joint members 138 by three fluid outlets. The joint members 138 include one inlet pipe section 138a and two branch pipe sections 138b. The inlet pipe section 138a is connected to the fluid outlet section of the water supply valve 152. Each branch pipe section 138b is connected to the distribution tube 136. The water pressure sensor 153a or the flow rate sensor 154a is provided in a passage downstream of the water supply valve 152, between the fluid outlet section of the water supply valve 152 and the inlet pipe section 138a. The first pipe section 51 of the water supply valve 152 is connected to the inlet pipe section 138a of the joint member 138. The second pipe section 52 of the water supply valve 152 is connected to the inlet pipe section 138a of the joint member 138. The third pipe section 53 of the water supply valve 152 is connected to the inlet pipe section 138a of the joint member 138. The irrigation system 10 can control the irrigation from the multiple distribution tubes 136 connected to the water supply valve 152 via the joint member 138 by individually controlling the valve opening degree for each water supply valve 152.

[0187] The irrigation system 10 of the fourth embodiment includes one water supply valve 152 having a plurality of fluid outlets each connected to a predetermined number of distribution tubes 136. This system can perform both drip irrigation and sprinkler irrigation from the distribution tube, and can reduce the number of flow control valves, thereby reducing parts and control costs.

[0188] <Fifth embodiment> The fifth embodiment will be described with reference to Fig. 23. The irrigation system 10 of the fifth embodiment has the passage configuration and components related to water supply control as shown in Fig. 23. The configurations, actions, and effects of the fifth embodiment that are not specifically described are the same as those of the previously described embodiments, and only the differences will be described below.

[0189] Fig. 23 shows an example of the positional relationship between distribution tube 137 and water supply valve 152. The passage configuration shown in Fig. 23 differs from the configuration shown in Fig. 19 in the configuration regarding the connection of water supply valve 152 to distribution tube 137.

[0190] As shown in FIG. 23, the first distribution tube 137 located closest to the pump 110 has a first distribution section 137a connected to an inlet port 251 of a first water supply valve 152. This water supply valve 152 has a first pipe section 51 connected to the vertical piping 133 and a second pipe section 52 open to the atmosphere. The first water supply valve 152 is a first water supply valve connected to communicate with the end of the first distribution section 137a opposite to the turn-back section. The second distribution section 137b of the first distribution tube 137 is connected to the first pipe section 51 of a second water supply valve 152 located next to the first distribution tube 152. The second pipe section 52 of the second water supply valve 152 is connected to the first distribution section 137a of a second distribution tube 137 located next to the first distribution tube 137. The inlet port 251 of the second water supply valve 152 is connected to the vertical piping 133. The second water supply valve 152 is a second water supply valve connected so as to communicate with the end portions of the first distribution section 137a and the second distribution section 137b opposite to the turn-back section.

[0191] The second distribution section 137b of the second distribution tube 137 is connected to the inlet port 251 of the third water supply valve 152 located next to the second water supply valve 152. The first pipe section 51 of the third water supply valve 152 is connected to the vertical piping 133. The second pipe section 52 of the third water supply valve 152 is open to the atmosphere. The third water supply valve 152 is a second water supply valve connected to communicate with the end of the second distribution section 137b of the second distribution tube 137 opposite to the turn-back section. The water pressure sensor 153a or the flow rate sensor 154a is provided in a passage downstream of the second water supply valve 152. The water pressure sensor 153a or the flow rate sensor 154a is provided, for example, between the fluid outlet section of the water supply valve 152 and the distribution tube 137.

[0192] Of the three adjacent water supply valves 152, the water supply valves 152 at both ends have one fluid outlet open to the atmosphere and the other connected to the pump 110, which is the water supply source. Furthermore, the inlet port 251 of each of the water supply valves 152 at both ends is connected to the distribution tube 137. The middle water supply valve 152 has a fluid outlet connected to the first distribution section 137a and the second distribution section 137b, and the inlet port 251 connected to the pump 110, which is the water supply source. As described above, the two adjacent distribution tubes 137 and the three water supply valves 152 form one group related to the irrigation passage. In the field 20, a plurality of irrigation passages forming this group are lined up in the y direction at predetermined intervals.

[0193] The irrigation system 10 can perform control to irrigate by discharging water from the distribution tube 137, and control to drain water from the fluid outlet of the water supply valve opened to the atmosphere via the distribution tube 137. When irrigating from the first distribution tube 137, the microcomputer 330 controls the valve opening of the second water supply valve 152 so that water flows down through the first pipe section 51. Furthermore, the microcomputer 330 controls the valve opening of the first water supply valve 152 so that water is blocked from flowing down to the fluid outlet. With this control, the water flows down from the first pipe section 51 of the second water supply valve 152 to the first distribution tube 137, and the irrigation water discharged from each through-hole is supplied to the field 20.

[0194] When draining water through the first distribution tube 137, the microcomputer 330 controls the valve opening of the second water supply valve 152 so that water flows down through the first pipe section 51. Furthermore, the microcomputer 330 controls the valve opening of the first water supply valve 152 so that water flows down to the second pipe section 52 that is open to the atmosphere. By this control, the supply water flows down from the first pipe section 51 of the second water supply valve 152 to the first distribution tube 137 and is drained from the second pipe section 52. By this drainage control, foreign matter can be discharged together with the drainage water from the first distribution tube 137, the water supply valve 152, the piping, etc.

[0195] When irrigating from the second distribution tube 137, the microcomputer 330 controls the valve opening of the second water supply valve 152 so that water flows down through the second pipe section 52. Furthermore, the microcomputer 330 controls the valve opening of the third water supply valve 152 so as to block the flow down to the fluid outflow section. By this control, the water flows down from the second pipe section 52 of the second water supply valve 152 to the second distribution tube 137, and the irrigation water discharged from each through-hole is supplied to the field 20.

[0196] When draining water through the second distribution tube 137, the microcomputer 330 controls the valve opening of the second water supply valve 152 so that water flows down through the second pipe section 52. Furthermore, the microcomputer 330 controls the valve opening of the third water supply valve 152 so that water flows down to the second pipe section 52 that is open to the atmosphere. By this control, the supply water flows down from the second pipe section 52 of the second water supply valve 152 to the second distribution tube 137 and is drained from the second pipe section 52. By this drainage control, foreign matter can be discharged together with the drainage water from the second distribution tube 137, the water supply valve 152, the piping, etc.

[0197] The irrigation system 10 of the fifth embodiment includes a first distribution section 137a, a second distribution section 137b, and a distribution tube 137 having a turn-back section, as in FIG. 19. The irrigation system 10 includes a first water supply valve connected to communicate with the end of the first distribution section opposite the turn-back section, and a second water supply valve connected to communicate with the end of the second distribution section opposite the turn-back section. The first water supply valve has a fluid inlet connected to communicate with the first distribution section, and an air opening section that is open to the atmosphere. The second water supply valve has a fluid inlet connected to communicate with a water supply pipe to which water is supplied from a water supply source, and a fluid outlet connected to communicate with the second distribution section. According to this configuration, the first water supply valve communicating with one distribution tube has an air opening section. Therefore, drainage through the air opening section of the second water supply valve, the distribution tube, and the first water supply valve communicating with the water supply pipe, and irrigation from the through hole of the distribution tube can be performed. Therefore, it is possible to provide an irrigation system 10 having a first water supply valve that functions as both an irrigation valve and a foreign matter discharge valve.

[0198] Sixth Embodiment The sixth embodiment will be described with reference to Figs. 24 to 27. The irrigation system 10 of the sixth embodiment has the passage configuration and components related to water supply control as shown in Fig. 24. The configurations, actions, and effects of the sixth embodiment that are not specifically described are the same as those of the previously described embodiments, and only the differences will be described below.

[0199] Fig. 24 shows an example of the positional relationship between the distribution tube 136 and the water supply valve 152. The passage configuration shown in Fig. 24 differs from the configuration shown in Fig. 17 in the configuration related to the water supply path for the distribution tube 136. The irrigation system 10 of the sixth embodiment includes a branch pipe 139 through which the water supply from the pump 110 branches and flows down. The branch pipe 139 branches from the vertical pipe 133 and communicates with the other end of the distribution tube 136. The other end of the distribution tube 136 is an end located on the other side in the longitudinal direction relative to one end of the distribution tube 136 located on the vertical pipe 133 side.

[0200] One end of the distribution tube 136 is connected to a fluid outlet portion of a water supply valve 152. This water supply valve 152 is connected to the vertical pipe 133 via an inlet port 251, similar to the configuration shown in Fig. 19. The water supply valve 152 and a water pressure sensor 153a or a flow rate sensor 154a are provided in the passage between one end of the distribution tube 136 and the vertical pipe 133. The water pressure sensor 153a or the flow rate sensor 154a is provided at a position closer to one end of the distribution tube 136 than the water supply valve 152.

[0201] The branch pipe 139 is a pipe branched from the vertical pipe 133 at a position closer to the pump 110 than the portion communicating with one end of the distribution tube 136. A plurality of passages communicating with one water supply valve 152 and one distribution tube 136 are connected to the branch pipe 139. The inlet ports 251 of the plurality of water supply valves 152 arranged in the same direction as the plurality of distribution tubes 136 are connected to the branch pipe 139. The other end of the distribution tube 136 is connected to the fluid outlet of the water supply valve 152. This water supply valve 152 is connected to the vertical pipe 133 via the inlet port 251. The water supply valve 152 and the water pressure sensor 153a or the flow rate sensor 154a are provided in the passage between the other end of the distribution tube 136 and the branch pipe 139. The water pressure sensor 153a or the flow rate sensor 154a is provided at a position closer to the other end of the distribution tube 136 than the water supply valve 152.

[0202] The irrigation system 10 individually controls the valve opening of the water supply valve 152 corresponding to each distribution tube 136, thereby individually controlling the amount of water discharged from the distribution tube 136 and the distance the water travels. The irrigation system 10 can supply water from one end of the distribution tube 136, from the other end, or from both ends at the same time. When supplying water from one end, the microcomputer 330 controls the valve opening of the water supply valve 152 at the one end connected to the vertical pipe 133 to an open state. Furthermore, the microcomputer 330 controls the valve opening of the water supply valve 152 at the other end connected to the branch pipe 139 to a closed state. By this control, the water supplied from one end through the vertical pipe 133 is discharged from the through hole of the distribution tube with a water travel distance and amount of irrigation water according to the valve opening, and is irrigated to the field 20.

[0203] When water is supplied from the other end, the microcomputer 330 controls the valve aperture of the water supply valve 152 on the other end side connected to the branch pipe 139 to an open state. Furthermore, the microcomputer 330 controls the valve aperture of the water supply valve 152 on the one end side connected to the vertical pipe 133 to a closed state. By this control, the water supplied from the other end through the branch pipe 139 is discharged from the through-hole of the distribution tube at a water flying distance and irrigation amount according to the valve aperture, and is irrigated to the field 20.

[0204] When water is supplied from both one end and the other end simultaneously, the microcomputer 330 controls the water supply valve 152 on the other end side and the water supply valve 152 on the one end side to be open. This control allows water to be supplied from one end through the vertical pipe 133 and water to be supplied from the other end through the branch pipe 139 simultaneously. The water supplied from both sides is mixed in the distribution tube 136 and discharged from the through-hole of the distribution tube 136 to irrigate the field 20.

[0205] Fig. 25 is a diagram for explaining the relationship between the water discharge position in the distribution tube 136 and the amount of irrigation. In Fig. 25, the horizontal axis represents the distance of the through hole from one end of the distribution tube 136, and the vertical axis represents the amount of irrigation. Water discharge position P1 is the position of the through hole closest to one end of the distribution tube 136. Water discharge position P2 is the position of the through hole closest to the other end of the distribution tube 136.

[0206] The dashed line graph in Fig. 25 shows irrigation in which the water supply valve 152 close to one end of the distribution tube 136 is controlled to an open state and the water supply valve 152 close to the other end is controlled to a closed state. In other words, the dashed line graph in Fig. 25 shows the relationship between the water discharge position and the amount of irrigation water in irrigation in which water is supplied only from the water supply valve 152 on the one end side. According to the dashed line graph, the amount of irrigation water is less at water discharge position P2, which is farther away from the one end to which water is supplied, in the distribution tube 136 than at water discharge position P1. Also, due to water flow resistance, the amount of irrigation water decreases the further away from water discharge position P1.

[0207] The dashed-dotted line graph in Figure 25 shows irrigation in which the water supply valve 152 closer to the other end of the distribution tube 136 is controlled to an open state and the water supply valve 152 closer to one end is controlled to a closed state. In other words, the dashed-dotted line graph in Figure 25 shows the relationship between the water discharge position and the amount of irrigation water in irrigation in which water is supplied only from the water supply valve 152 on the other end side. According to the dashed-dotted line graph, the amount of irrigation water is less at water discharge position P1, which is farther away from the other end to which water is supplied, in the distribution tube 136, than at water discharge position P2. Also, due to water flow resistance, the amount of irrigation water decreases the further away from water discharge position P2.

[0208] The solid line graph in Fig. 25 shows the total irrigation amount combining the dashed line graph and the dashed line graph. In other words, the solid line graph in Fig. 25 shows the total irrigation amount of the irrigation amount by water supply from one end and the other end. The variation in the irrigation amount in the solid line graph is smaller than the difference in the irrigation amount between the upstream and downstream shown in the dashed line graph and the difference in the irrigation amount between the upstream and downstream shown in the dashed line graph. The irrigation system 10 can suppress the variation in the irrigation amount due to the water discharge position by irrigation control that switches between irrigation from one end and irrigation from the other end.

[0209] FIG. 26 is a diagram for explaining the relationship between the water discharge position and the amount of irrigation water in the distribution tube 136. In FIG. 26, the horizontal axis represents the distance from one end of the distribution tube 136 to the through hole, and the vertical axis represents the amount of irrigation water. The dashed line graph in FIG. 26 is the same as the dashed line graph in FIG. 25, and shows the relationship between the water discharge position and the amount of irrigation water in irrigation water supplied only from the water supply valve 152 on the one end side. The solid line graph in FIG. 26 shows the relationship between the water discharge position and the amount of irrigation water in irrigation water supplied simultaneously from both one end and the other end. The variation in the amount of irrigation water in the solid line graph is smaller than the difference in the amount of irrigation water upstream and downstream shown by the dashed line graph. The irrigation system 10 can suppress the reduction in the amount of irrigation water due to water flow resistance by irrigation control that supplies water simultaneously from both one end and the other end, and can suppress the variation in the amount of irrigation water due to the water discharge position.

[0210] The thick line in Fig. 27 indicates the relationship between the water discharge position of the distribution tube 136 and the amount of irrigation water in a farm field 20 in which the ground level is higher on the other end side than on the one end side. The thin line in Fig. 27 indicates the relationship between the water discharge position of the distribution tube 136 and the amount of irrigation water in a farm field 20 in which the ground level is approximately the same on the other end side and on the one end side. In Fig. 27, the horizontal axis represents the distance from one end of the distribution tube 136 to the through hole, and the vertical axis represents the amount of irrigation water.

[0211] In the dashed line graph of FIG. 27, both the thick line and the thin line show the relationship between the water discharge position and the amount of irrigation water in irrigation where water is supplied only from the water supply valve 152 on one end side. According to the dashed line graph, the amount of irrigation water at the water discharge position close to the other end is reduced more in the thick line than in the thin line. The difference in the amount of irrigation water at the water discharge position near the other end is AW1 shown in FIG. 27. This is because water is supplied from one end where the ground is low and flows down toward the other end where the ground is high. In the dashed line graph of FIG. 27, both the thick line and the thin line show the relationship between the water discharge position and the amount of irrigation water in irrigation where water is supplied only from the water supply valve 152 on the other end side. According to the dashed line graph, the amount of irrigation water is greater in the thick line, which is a condition where the ground of the other end is high, than in the thin line.

[0212] The thick solid line graph in Fig. 27 indicates the total irrigation amount combining the thick dashed line graph and the thick dashed line graph. The thin solid line graph in Fig. 27 indicates the total irrigation amount combining the thin dashed line graph and the thin dashed line graph. That is, both the thick and thin solid lines in Fig. 27 indicate the total irrigation amount of the irrigation amount by water supply from one end and the irrigation amount by water supply from the other end. The irrigation system 10 can suppress the variation in the irrigation amount due to the water discharge position in a farm field 20 with a difference in elevation by controlling to switch between irrigation from one end and irrigation from the other end.

[0213] The irrigation system 10 of the sixth embodiment includes a water supply valve 152 on one end side and a water supply valve 152 on the other end side. The control device controls the valve opening of the water supply valve 152 so as to switch between a control for supplying water from one end side and a control for supplying water from the other end side. In the control for supplying water from one end side, the fluid outlet of the water supply valve 152 on the one end side is opened and the fluid outlet of the water supply valve 152 on the other end side is closed. In the control for supplying water from the other end side, the fluid outlet of the water supply valve 152 on the other end side is opened and the fluid outlet of the water supply valve 152 on the one end side is closed. According to the irrigation system 10, the variation in the amount of irrigation water due to the water flow resistance can be suppressed by the irrigation control that switches between irrigation water supplied from one end side and irrigation water supplied from the other end side. In addition, according to this irrigation control, the variation in the amount of irrigation water due to the water discharge position can be suppressed in a distribution tube that is provided so that there is a height difference in the tube length direction.

[0214] Seventh embodiment The seventh embodiment will be described with reference to Fig. 28. The irrigation system 10 of the seventh embodiment has the passage configuration and components related to water supply control as shown in Fig. 28. The configurations, actions, and effects of the seventh embodiment that are not specifically described are the same as those of the previously described embodiments, and only the differences will be described below.

[0215] FIG. 28 shows an example of the positional relationship between the distribution tube 136 and the water supply valve 152. The passage configuration shown in FIG. 28 differs from the configuration shown in FIG. 24 of the sixth embodiment in that an on-off valve 140 is provided in the branch pipe 139. The irrigation system 10 of the seventh embodiment is provided with an on-off valve 140 that can open and close a passage downstream of a connection part with the water supply valve 152 in the branch pipe 139. The on-off valve 140 has a fluid inflow part connected to the branch pipe 139 and a fluid outflow part open to the atmosphere. The on-off valve 140 has a function of controlling the downstream passage in the branch pipe 139 between an open state and a closed state, and a flow control valve, a solenoid valve, or the like can be used.

[0216] This irrigation system 10 performs the same control as in the sixth embodiment with respect to the valve opening control of each water supply valve 152. The microcomputer 330 controls the valve opening of the on-off valve 140 between an open state and a closed state. The irrigation system 10 can perform control to irrigate by discharging water from the distribution tube 136, and control to drain water from the fluid outlet portion of the water supply valve that is open to the atmosphere via the distribution tube 136.

[0217] When water is supplied from the other end of the distribution tube 136 for irrigation, the microcomputer 330 controls the water supply valve on the corresponding other end side to an open state and the water supply valve on the one end side to a closed state. Furthermore, the microcomputer 330 controls the on-off valve 140 to a closed state. By this control, the water supplied via the branch pipe 139 flows into the distribution tube 136 from the other end and is discharged from each through-hole to the field 20. When water is supplied from one end of the distribution tube 136 for irrigation, the microcomputer 330 controls the water supply valve on the corresponding one end side to an open state and the water supply valve on the other end side to a closed state, and controls the on-off valve 140 to a closed state. By this control, the water supplied via the branch pipe 139 flows into the distribution tube 136 from one end and is discharged from each through-hole to the field 20.

[0218] When draining water through distribution tube 136, microcomputer 330 controls the corresponding water supply valve on one end side to an open state and the water supply valve on the other end side to a closed state. Microcomputer 330 also controls on-off valve 140 to an open state. With this control, the water flows down the water supply valve on one end side, distribution tube 136, and the water supply valve on the other end side in that order, and is drained from the fluid outlet of on-off valve 140 via branch piping 139. With this drainage control, foreign matter in the water supply valve on one end side, distribution tube 136, water supply valve on the other end side, piping, etc. can be discharged together with the drainage water.

[0219] Eighth embodiment The eighth embodiment will be described with reference to Fig. 29. The irrigation system 10 of the eighth embodiment has the passage configuration and components related to water supply control as shown in Fig. 29. The configurations, actions, and effects of the eighth embodiment that are not specifically described are the same as those of the previously described embodiments, and only the differences will be described below.

[0220] Fig. 29 shows an example of the positional relationship between the distribution tube 137 and the water supply valve 14. The passage configuration shown in Fig. 29 differs from the configuration shown in Fig. 28 in the configuration regarding the connection of the water supply valve 14 to the distribution tube 136. The irrigation system 10 of the eighth embodiment controls the valve opening of the water supply valve 14 to perform irrigation by discharging water from the distribution tube 136 and draining water via the distribution tube 136.

[0221] The irrigation system 10 of the eighth embodiment includes a plurality of water supply valves 14, each of which has its valve opening controlled individually. The water supply valve 14 has an air opening section 142 that is open to the atmosphere, and a plurality of passage connections. The plurality of passage connections include a first passage connection section 141, a second passage connection section 143, and a third passage connection section 144. The first passage connection section 141 is connected to a passage that communicates with the vertical pipe 133 or the branch pipe 139 through which the water supply from the water supply source flows down. The second passage connection section 143 is connected to a passage that communicates with one end or the other end of the distribution tube 136. The third passage connection section 144 is connected to a passage that communicates with one end or the other end of the distribution tube 136.

[0222] As shown in FIG. 29, the water supply valve 14 located on one end side of the distribution tube 136 is a flow rate control valve that communicates one end of the distribution tube 136 with the vertical pipe 133. The first passage connection part 141 of the water supply valve 14 on the one end side is connected to the vertical pipe 133. The air opening part 142 of the water supply valve 14 on the one end side is provided so as to be open to the atmosphere. The second passage connection part 143 of the water supply valve 14 on the one end side is connected to one end of the first distribution tube 136 located closest to the pump 110. The third passage connection part 144 of the water supply valve 14 on the one end side is connected to one end of the second distribution tube 136 located next to the first distribution tube 136. The first distribution tube 136 is the first distribution tube. The second distribution tube 136 is the second distribution tube.

[0223] The water supply valve 14 located on the other end side of the distribution tube 136 is a flow rate adjustment valve that communicates the other end of the distribution tube 136 with the branch pipe 139. A first passage connection part 141 of the water supply valve 14 on the other end side is connected to the branch pipe 139. An atmosphere opening part 142 of the water supply valve 14 on the other end side is provided so as to be open to the atmosphere. A second passage connection part 143 of the water supply valve 14 on the other end side is connected to the other end of the first distribution tube 136. A third passage connection part 144 of the water supply valve 14 on the other end side is connected to the other end of the second distribution tube 136.

[0224] The water pressure sensor 153a or the flow rate sensor 154a is provided in a passage downstream of the water supply valve 14 on one end side. The water pressure sensor 153a or the flow rate sensor 154a is provided in a passage downstream of the water supply valve 14 on the other end side. The water pressure sensor 153a or the flow rate sensor 154a is provided, for example, between the fluid outlet of the water supply valve 14 on one end side and the distribution tube 136. The water pressure sensor 153a or the flow rate sensor 154a is provided, for example, between the fluid outlet of the water supply valve 14 on the other end side and the distribution tube 136. As described above, two adjacent distribution tubes 136 and two water supply valves 14 located at both ends of the distribution tube form one group related to the irrigation passage. A plurality of irrigation passages forming this group are arranged in the y direction at a predetermined interval in the field 20.

[0225] The irrigation system 10 can perform control to discharge water from the distribution tube 136 for irrigation, and control to discharge water from the air opening part of the water supply valve 14 via the distribution tube 136. When irrigating from the first distribution tube, the microcomputer 330 controls the valve opening to open the second passage connection part 143 of the water supply valve on one end side and close the third passage connection part 144. Furthermore, the microcomputer 330 controls the valve opening to close the second passage connection part 143 and the third passage connection part 144 of the water supply valve on the other end side. By this control, the water flows down from the second passage connection part 143 of the water supply valve on one end side to the first distribution tube 136, and the irrigation water discharged from each through hole is supplied to the field 20.

[0226] When irrigating from the first distribution tube, microcomputer 330 controls the valve opening to open second passage connection 143 of the water supply valve on the other end side and close third passage connection 144. Microcomputer 330 further controls the valve opening to close second passage connection 143 and third passage connection 144 of the water supply valve on one end side. This control causes the water to flow down from second passage connection 143 of the water supply valve on the other end side to the first distribution tube 136, and irrigation water discharged from each through-hole is supplied to the field 20.

[0227] In the case of drainage via the first distribution tube, microcomputer 330 controls the valve opening to open second passage connection 143 of the water supply valve on one end side and close third passage connection 144. Microcomputer 330 further controls the valve opening to open second passage connection 143 of the water supply valve on the other end side and close third passage connection 144. With this control, the water is drained from second passage connection 143 of the water supply valve on one end side through the first distribution tube 136 and from the atmosphere opening part 142 of the water supply valve on the other end side. With this drainage control, foreign matter can be discharged together with the drainage from the water supply valve on one end side, the first distribution tube 136, the water supply valve on the other end side, etc.

[0228] In the case of drainage via the first distribution tube, microcomputer 330 controls the valve opening to open second passage connection 143 of the water supply valve on the other end side and close third passage connection 144. Microcomputer 330 further controls the valve opening to open second passage connection 143 of the water supply valve on one end side and close third passage connection 144. With this control, the water is drained from second passage connection 143 of the water supply valve on the other end side through the first distribution tube 136 and from the atmosphere opening part 142 of the water supply valve on one end side. With this drainage control, foreign matter can be discharged together with the drainage from the water supply valve on the other end side, the first distribution tube 136, the water supply valve on one end side, etc.

[0229] When irrigating from the second distribution tube, microcomputer 330 controls the valve opening to close second passage connection 143 of the water supply valve on one end side and open third passage connection 144. Microcomputer 330 further controls the valve opening to close second passage connection 143 and third passage connection 144 of the water supply valve on the other end side. With this control, the water flows down from third passage connection 144 of the water supply valve on one end side to the second distribution tube 136, and irrigation water discharged from each through-hole is supplied to the field 20.

[0230] When irrigating from the second distribution tube, microcomputer 330 controls the valve opening to close second passage connection 143 of the water supply valve on the other end side and open third passage connection 144. Microcomputer 330 further controls the valve opening to close second passage connection 143 of the water supply valve on one end side and close third passage connection 144. This control causes the water to flow down from third passage connection 144 of the water supply valve on the other end side to the second distribution tube 136, and irrigation water discharged from each through-hole is supplied to the field 20.

[0231] In the case of drainage via the second distribution tube, microcomputer 330 controls the valve opening to close second passage connection 143 of the water supply valve on one end side and open third passage connection 144. Microcomputer 330 further controls the valve opening to close second passage connection 143 of the water supply valve on the other end side and open third passage connection 144. With this control, the water is drained from second passage connection 143 of the water supply valve on one end side through second distribution tube 136 and from atmosphere opening part 142 of the water supply valve on the other end side. With this drainage control, foreign matter can be discharged together with the drainage from the water supply valve on one end side, second distribution tube 136, the water supply valve on the other end side, etc.

[0232] In the case of drainage via the second distribution tube, microcomputer 330 controls the valve opening to close second passage connection 143 of the water supply valve on the other end side and open third passage connection 144. Microcomputer 330 further controls the valve opening to close second passage connection 143 of the water supply valve on one end side and open third passage connection 144. With this control, the water is drained from third passage connection 144 of the water supply valve on the other end side through the second distribution tube 136 and from the atmosphere opening part 142 of the water supply valve on the one end side. With this drainage control, foreign matter can be discharged together with the drainage from the water supply valve on the other end side, the second distribution tube 136, the water supply valve on the one end side, etc.

[0233] The irrigation system 10 of the eighth embodiment includes a first distribution tube, a second distribution tube adjacent to the first distribution tube, a water supply valve 14 on one end side, and a water supply valve 14 on the other end side. The water supply valve 14 on the one end side is connected to communicate with one end of the first distribution tube and one end of the second distribution tube. The water supply valve on the other end side is connected to communicate with the other end of the first distribution tube and the other end of the second distribution tube. The water supply valve 14 on the one end side has an air opening part 142 that is open to the atmosphere, a first passage connection part 141, a second passage connection part 143, and a third passage connection part 144. The first passage connection part 141 is connected to a passage so as to communicate with a water supply pipe 130 to which water is supplied from a water supply source. The second passage connection part 143 is connected to a passage so as to communicate with one end of the first distribution tube. The third passage connection part 144 is connected to the passage so as to communicate with one end of the second distribution tube. The water supply valve on the other end side has an atmosphere opening part 142 that is open to the atmosphere, a first passage connection part 141, a second passage connection part 143, and a third passage connection part 144. The first passage connection part 141 is connected to the passage so as to communicate with a branch pipe 139 that branches off from the water supply pipe 130. The second passage connection part 143 is connected to the passage so as to communicate with the other end of the first distribution tube. The third passage connection part 144 is connected to the passage so as to communicate with the other end of the second distribution tube.

[0234] According to this system, the variation in the amount of irrigation water caused by water flow resistance can be suppressed by controlling irrigation water by switching between irrigation water supplied from one end and irrigation water supplied from the other end. Furthermore, this system can perform drainage through the distribution tube and the atmospheric opening part of the water supply valve 14, and irrigation water from the through hole of the distribution tube. Therefore, it is possible to provide an irrigation system 10 having a water supply valve that functions as both an irrigation valve and a foreign object discharge valve.

[0235] <Other embodiments> The disclosure of this specification is not limited to the exemplified embodiments. The disclosure includes the exemplified embodiments and modifications by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of parts and elements shown in the embodiments, and can be implemented in various modifications. The disclosure can be implemented by various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes those in which parts and elements of the embodiments are omitted. The disclosure includes the replacement or combination of parts and elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is indicated by the description of the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the description of the claims. [Explanation of symbols]

[0236] 14...water supply valve, 20...field, 30...plant, 51...first pipe section (fluid outlet section) 52... second pipe section (atmospheric opening section), 110... pump (water supply source), 130... water supply piping 136, 137... distribution tube, 137a... first distribution section, 137b... second distribution section 139...Branch piping, 140...Shut-off valve, 152...Water supply valve 153a, 153b...water pressure sensor, 154a, 154b...flow rate sensor 251...inlet port (fluid inlet portion), 330...microcomputer (control device) 332: signal output unit (output unit), 334: processing unit (arithmetic unit)< / rtc>

Claims

1. A distribution tube (136; 137) that is provided in a field (20) in which a plant (30) is grown, has a plurality of through holes for spraying irrigation water to the field, and does not have a pressure compensation mechanism; a water supply valve (152) upstream of the distribution tube for controlling the pressure of the water flowing down the distribution tube; A control device (330) for controlling the valve opening of the water supply valve to control the amount of irrigation water discharged from the distribution tube through the through hole; An irrigation system comprising:

2. A water pressure sensor (153a, 153b) or a flow rate sensor (154a, 154b) is provided to detect water supply information in an upstream passage flowing down toward the through hole of the distribution tube or at a downstream end of the distribution tube, The irrigation system according to claim 1 , wherein the control device controls the valve opening degree by feedback control using the detected water supply information.

3. The water pressure sensor or the flow rate sensor detects the water supply information at the upstream passage and the downstream end, The irrigation system according to claim 2 , wherein the control device controls the valve opening degree by feedback control using the water supply information detected at the upstream passage and the downstream end.

4. The control device controls the current flow time or current flow amount required to control the valve opening to a target opening in stages, in increments divided into multiple stages, thereby controlling the valve opening to the target opening in stages.The control device controls the current flow time or current flow amount required to control the valve opening to a target opening in stages, increments divided into multiple stages, thereby controlling the valve opening to the target opening in stages.

5. The distribution tube is configured to expand and contract in response to water pressure flowing therethrough, The irrigation system according to any one of claims 1 to 4, wherein the control device controls the valve opening of the water supply valve within a range of water pressure at which the distribution tube expands and contracts.

6. The distribution tube has a first distribution section (137a) in which a plurality of through holes are formed, a second distribution section (137b) extending along the first distribution section and aligned with the first distribution section at intervals, in which a plurality of through holes are formed, and a folded-back section connecting the first distribution section and the second distribution section, An irrigation system described in any one of claims 1 to 5, wherein the water supply valve controls the pressure of the water flowing downward toward the end opposite the turn-back section in each of the first distribution section and the second distribution section.

7. The irrigation system according to any one of claims 1 to 5, wherein one of the water supply valves is provided in a passage upstream of the distribution tubes so as to communicate with a predetermined number of the distribution tubes.

8. 8. The watering system according to claim 7, wherein one of the water supply valves has a plurality of fluid outlets each provided to communicate with a predetermined number of the distribution tubes.

9. The distribution tube has a first distribution section (137a) in which a plurality of through holes are formed, a second distribution section (137b) extending along the first distribution section and aligned with the first distribution section at intervals, in which a plurality of through holes are formed, and a folded-back section connecting the first distribution section and the second distribution section, the water supply valve includes a first water supply valve connected to communicate with an end of the first distribution section opposite the turn-back section, and a second water supply valve connected to communicate with an end of the second distribution section opposite the turn-back section, The first water supply valve has a fluid inlet portion (251) connected to communicate with the first distribution portion and an atmosphere opening portion (52) open to the atmosphere, The second water supply valve has a fluid inlet portion (251) connected to communicate with a water supply piping (130) to which water is supplied from a water supply source (110), and a fluid outlet portion (51) connected to communicate with the second distribution portion. An irrigation system as described in any one of claims 1 to 5.

10. The water supply valve includes a water supply valve on one end side having a fluid inlet portion (251) connected to communicate with a water supply pipe (130) to which water is supplied from a water supply source (110) and a fluid outlet portion (51) connected to communicate with one end of the distribution tube, and a water supply valve on the other end side having a fluid inlet portion (251) connected to communicate with a branch pipe (139) branching off from the water supply pipe and a fluid outlet portion (51) connected to communicate with the other end of the distribution tube, The control device controls the valve opening so as to switch between a control in which the fluid outflow portion of the water supply valve on the one end side is opened and the fluid outflow portion of the water supply valve on the other end side is closed to supply water from the one end, and a control in which the fluid outflow portion of the water supply valve on the other end side is opened and the fluid outflow portion of the water supply valve on the one end side is closed to supply water from the other end.An irrigation system as described in any one of claims 1 to 5.

11. an on-off valve (140) capable of opening and closing a passage downstream of a connection portion between the branch pipe and the water supply valve on the other end side; The irrigation system according to claim 10 , wherein the on-off valve has a fluid inlet connected to the branch pipe and a fluid outlet open to the atmosphere.

12. the water supply valve includes a water supply valve on one end side connected to communicate with one end of a first distribution tube and one end of a second distribution tube adjacent to the first distribution tube, and a water supply valve on the other end side connected to communicate with the other end of the first distribution tube and the other end of the second distribution tube, The water supply valve on the one end side has an atmosphere opening part (142) that is open to the atmosphere, a first passage connection part (141) connected so as to communicate with a water supply pipe (130) to which water is supplied from a water supply source (110), a second passage connection part (143) connected so as to communicate with the one end of the first distribution tube, and a third passage connection part (144) connected so as to communicate with the one end of the second distribution tube, The water supply valve on the other end side has an atmosphere opening portion (142) open to the atmosphere, a first passage connection portion (141) connected to communicate with a branch pipe (139) branching off from the water supply pipe, a second passage connection portion (143) connected to communicate with the other end of the first distribution tube, and a third passage connection portion (144) connected to communicate with the other end of the second distribution tube. An irrigation system as described in any one of claims 1 to 5.

13. A calculation unit (334) for determining a valve opening degree of a water supply valve (152) for controlling the pressure of irrigation water flowing down into a distribution tube (136) having a plurality of through holes and no pressure compensation mechanism, upstream of the distribution tube; An output unit (332) that outputs a control signal to the water supply valve to control the valve opening in order to control the amount of irrigation water discharged from the distribution tube through the through hole; A control device comprising:

14. The control device described in claim 13, wherein the output unit controls the current flow time or current flow amount required to control the valve opening to a target opening in increments divided into a plurality of stages, and outputs a control signal to the water supply valve to control the valve opening to the target opening in stages.

15. The control device according to claim 13 or 14, wherein the output section outputs a control signal to the water supply valve that controls the valve opening within a range of water pressure at which the distribution tube, which is configured to expand and contract in response to the water pressure circulating therethrough, expands and contracts.

Images