A two-stage self-adaptive drip irrigation system and an irrigation method

Abstract

The present application relates to a kind of two-stage adaptive drip irrigation system and irrigation method, system includes multiple irrigation branch pipes in parallel in downstream of water supply main line, system hydraulic distribution unit is set in main line and terminal humidity response unit is set on each branch pipe.Humidity response unit according to local soil humidity adjusts its own flow capacity to change the real-time fluid resistance of irrigation branch pipe where it is;The resistance of all branch pipes is connected in parallel to form downstream total resistance.System hydraulic distribution unit is adjusted according to the change of the total resistance of system total water inflow, and based on the hydraulic characteristics of parallel pipe, it is distributed to the branch pipe with smaller real-time resistance.This application works by using hydraulic and material characteristics, without external energy and control, solves the deployment difficulty of electric control system in remote areas and the uneven irrigation problem of traditional passive device, realizes the global optimization distribution and end on-demand control of irrigation water resources under passive conditions, and the deployment and maintenance cost is lower.

Description

Technical Field

[0001] This invention belongs to the field of water-saving sprinkler irrigation equipment, specifically relating to a two-stage adaptive drip irrigation system and irrigation method. Background Technology

[0002] The technical approaches to achieving precision drip irrigation mainly fall into two categories. One is the active control system, which uses a central controller, electric valves, and sensors. This approach offers high control precision but relies on a continuous power supply and complex signal wiring, resulting in high system costs. Especially in remote agricultural areas, insufficient power grid and communication network coverage, coupled with the extremely high cost of laying dedicated lines, severely limits the application of active control solutions. The other type is passive devices, such as fixed-flow mechanical drip heads. These have a simple structure and can operate independently, but they cannot dynamically adjust the flow rate based on soil moisture or achieve optimal water resource allocation at the system level, potentially leading to over-irrigation in some areas and insufficient water supply in others. Therefore, a passive drip irrigation solution that can simultaneously achieve system allocation and terminal control is currently needed. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, this invention provides a two-stage adaptive drip irrigation system and irrigation method. The technical problem to be solved by this invention is achieved through the following technical solution:

[0004] This invention provides a two-stage adaptive drip irrigation system, in which multiple irrigation branches are connected in parallel downstream of the main water supply pipeline to form an irrigation fluid network. The system includes: a system hydraulic distribution unit and multiple terminal humidity response units. The system hydraulic distribution unit is disposed in the main water supply pipeline and is used to adjust the total inflow of the irrigation fluid network according to its downstream fluid resistance. Each irrigation branch is provided with at least one terminal humidity response unit, and each terminal humidity response unit is used to adjust its own flow capacity according to the local soil moisture. The multiple terminal humidity response units on the same irrigation branch constitute the real-time fluid resistance of the irrigation branch. The real-time fluid resistances of all irrigation branches are superimposed in parallel to constitute the downstream fluid resistance. The system hydraulic distribution unit is configured to adjust the total inflow of the irrigation fluid network inversely according to the change in the downstream fluid resistance.

[0005] In one embodiment of the present invention, the system hydraulic distribution unit includes a venturi tube and a hydraulic feedback regulating valve. The venturi tube is connected in series to the main water supply pipeline, and a pressure tap is provided at the throat of the venturi tube. The hydraulic feedback regulating valve is located upstream of the venturi tube, and the opening degree of the hydraulic feedback regulating valve is controlled by the throat pressure of the venturi tube obtained through the pressure tap. The throat pressure increases with the increase of the downstream fluid resistance and decreases with the decrease of the downstream fluid resistance. The hydraulic feedback regulating valve is configured to decrease its opening degree in response to the increase of the throat pressure and increase its opening degree in response to the decrease of the throat pressure.

[0006] In one embodiment of the present invention, the hydraulic feedback regulating valve includes: a valve body, a diaphragm, a valve core, and an elastic member; wherein, the diaphragm is disposed in the valve body and divides the inner cavity of the valve body into an upper control cavity and a lower flow cavity that are isolated from each other, the upper control cavity being in communication with the pressure tap; the valve core is connected to the diaphragm and is driven by the diaphragm to change the flow area of ​​the lower flow cavity, thereby changing the opening degree of the hydraulic feedback regulating valve; the elastic member is connected to the valve core and is used to provide the valve core with an elastic force that tends to increase the flow area of ​​the lower flow cavity.

[0007] In one embodiment of the present invention, each terminal humidity response unit includes a drip irrigation head housing, a humidity sensing drive, and a flow regulating valve. The drip irrigation head housing has an inlet, an outlet, and a permeable section. The inlet is connected to the irrigation branch, and the inlet and the outlet are connected through a flow cavity. The humidity sensing drive is disposed within the drip irrigation head housing near the permeable section. The humidity sensing drive is made of a humidity-sensitive material, and the volume of the humidity-sensitive material reversibly changes with the local soil moisture. The flow regulating valve is disposed within the flow cavity between the inlet and the outlet and is connected to the humidity sensing drive. The flow regulating valve is used to change the flow area of ​​the humidity sensing drive according to the volume change of the humidity sensing drive, thereby adjusting the flow capacity of the terminal humidity response unit.

[0008] In one embodiment of the present invention, the permeable part is provided with a porous structure for water to pass through, and the humidity sensing drive is disposed in the drip head housing and exchanges moisture with the external environment through the porous structure of the permeable part.

[0009] In one embodiment of the present invention, the flow regulating valve includes a conical valve plug and a valve seat that cooperates with the conical valve plug; the humidity sensing drive is connected to the conical valve plug and drives the conical valve plug to move axially relative to the valve seat, so as to change the area of ​​the annular flow gap between the conical valve plug and the valve seat, thereby changing the flow capacity of the flow regulating valve.

[0010] In one embodiment of the present invention, the volume of the humidity-sensitive material increases with the increase of local soil moisture and decreases with the decrease of local soil moisture; the humidity-sensitive material is one or more of polyacrylamide hydrogel, polyvinyl alcohol hydrogel, or polyacrylate copolymer hydrogel.

[0011] In one embodiment of the present invention, the flow capacity of the terminal humidity response unit is manifested as the outflow rate of the irrigation branch in which it is located. When the local soil moisture where the terminal humidity response unit is located increases, moisture exchange occurs with the external environment through the porous structure of the permeable part, increasing the volume of the humidity-sensitive material and decreasing the area of ​​the annular flow gap between the conical valve plug and the valve seat. This reduces the flow capacity of the flow regulating valve, thereby causing the outflow rate of the irrigation branch to decrease as the local soil moisture increases. Conversely, when the local soil moisture where the terminal humidity response unit is located decreases, moisture exchange occurs with the external environment through the porous structure of the permeable part, decreasing the volume of the humidity-sensitive material and increasing the area of ​​the annular flow gap between the conical valve plug and the valve seat. This increases the flow capacity of the flow regulating valve, thereby causing the outflow rate of the irrigation branch to increase as the local soil moisture decreases.

[0012] This invention also provides a two-stage adaptive drip irrigation method, employing the aforementioned two-stage adaptive drip irrigation system, the method comprising:

[0013] Step 1: The terminal humidity response units on the multiple irrigation branches connected in parallel sense the local soil moisture and adjust the overcurrent capacity of each terminal humidity response unit.

[0014] Step 2: By adjusting the overcurrent capacity of each terminal humidity response unit, the real-time fluid resistance of the irrigation branch is changed. The real-time fluid resistance is used to characterize the water demand status of the irrigation branch.

[0015] Step 3: The real-time fluid resistance changes of the multiple irrigation branches cause changes in the downstream fluid resistance of the hydraulic distribution unit set in the main water supply pipeline system. The downstream fluid resistance is used to characterize the overall water demand status of the irrigation fluid network.

[0016] Step 4: The total inflow rate of the irrigation fluid network is adjusted inversely according to the change in downstream fluid resistance by the system hydraulic distribution unit, and the real-time flow rate of each irrigation branch is adjusted according to the real-time fluid resistance of the multiple irrigation branches.

[0017] In one embodiment of the present invention, step 4 specifically includes: when the downstream fluid resistance changes, the flow rate through the system hydraulic distribution unit is changed, the throat pressure of the system hydraulic distribution unit changes, and the change in throat pressure drives the hydraulic feedback regulating valve to change its opening, thereby regulating the total inflow of the irrigation fluid network; at the same time, the real-time flow rate of each irrigation branch is adjusted according to the real-time fluid resistance of the multiple irrigation branches.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The two-stage adaptive drip irrigation system of this invention has a hydraulic distribution unit installed in the main water supply line. This unit inversely adjusts the total inflow of the irrigation fluid network based on changes in downstream fluid resistance. When the soil in the irrigation area is generally dry, the opening of each terminal humidity response unit is large, resulting in low downstream fluid resistance. The system's hydraulic distribution unit increases the total inflow to meet overall demand. When soil moisture increases in certain areas, the opening of the terminal humidity response units in those areas decreases, leading to increased fluid resistance on their respective irrigation branches. The combined fluid resistance of all irrigation branches increases downstream fluid resistance, prompting the system's hydraulic distribution unit to reduce the total inflow and avoid water waste. During the dynamic process of total flow adjustment, since the flow distribution of parallel-connected irrigation branches tends to follow the path with less resistance, when the system's hydraulic distribution unit adjusts the total flow in response to changes in total resistance, the irrigation branches with relatively lower real-time fluid resistance—that is, those with larger terminal humidity response unit openings and drier soil—will receive a larger proportion of the increased inflow, allowing water to prioritize areas with more urgent water needs. The two-stage adaptive drip irrigation system of the present invention achieves adaptive regulation of global water volume and optimization of regional flow through mechanical structure, without the need for external energy or control signals, and is suitable for remote agricultural areas lacking power and communication infrastructure.

[0020] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a two-stage adaptive drip irrigation system provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of the Venturi tube provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the hydraulic feedback regulating valve provided in an embodiment of the present invention;

[0024] Figure 4 This is a structural cross-sectional view of the hydraulic feedback regulating valve provided in an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of the terminal humidity response unit provided in an embodiment of the present invention;

[0026] Figure 6 This is a structural cross-sectional view of the terminal humidity response unit provided in an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram illustrating the working principle of the two-stage adaptive drip irrigation system provided in this embodiment of the invention;

[0028] Figure 8 This is a flowchart of a two-stage adaptive irrigation method provided in an embodiment of the present invention.

[0029] Reference numerals: 10-Main water supply line; 20-Irrigation branch line; 1-System hydraulic distribution unit; 11-Venturi tube; 12-Hydraulic feedback regulating valve; 121-Valve body; 122-Diaphragm; 123-Valve core; 124-Elastic component; 2-Terminal humidity response unit; 21-Drip head housing; 211-Permeable section; 22-Humidity sensing drive; 23-Flow regulating valve; 231-Conical valve plug; 232-Valve seat. Detailed Implementation

[0030] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description of a two-stage adaptive drip irrigation system and irrigation method based on the present invention is provided in conjunction with the accompanying drawings and specific embodiments.

[0031] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0032] Example 1

[0033] like Figures 1 to 7 As shown, Figure 1This is a schematic diagram of the structure of a two-stage adaptive drip irrigation system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the Venturi tube provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the hydraulic feedback regulating valve provided in an embodiment of the present invention; Figure 4 This is a structural cross-sectional view of the hydraulic feedback regulating valve provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the terminal humidity response unit provided in an embodiment of the present invention; Figure 6 This is a structural cross-sectional view of the terminal humidity response unit provided in an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the working principle of the two-stage adaptive drip irrigation system provided in this embodiment of the invention.

[0034] In this embodiment, multiple irrigation branch lines 20 are connected in parallel downstream of the main water supply pipeline 10 to form an irrigation fluid network. The two-stage adaptive drip irrigation system includes: a system hydraulic distribution unit 1 and multiple terminal humidity response units 2. The system hydraulic distribution unit 1 is located in the main water supply pipeline 10 and is used to adjust the total inflow of the irrigation fluid network according to the downstream fluid resistance. Each irrigation branch line 20 is provided with at least one terminal humidity response unit 2, and each terminal humidity response unit 2 is used to adjust its own flow capacity according to the local soil moisture.

[0035] Multiple terminal humidity response units 2 on the same irrigation branch 20 together constitute the real-time fluid resistance of the irrigation branch 20. The real-time fluid resistance is used to characterize the water demand state of the irrigation branch 20. The real-time fluid resistances of all irrigation branches 20 are superimposed in parallel to constitute the downstream fluid resistance. The downstream fluid resistance is used to characterize the overall water demand state of the irrigation fluid network. The system hydraulic distribution unit 1 is configured to adjust the total inflow of the irrigation fluid network inversely according to the change of the downstream fluid resistance, that is, when the downstream resistance increases, the total inflow decreases.

[0036] Specifically, the system hydraulic distribution unit 1 is installed in the main water supply pipeline 10, and adjusts the total inflow of the irrigation fluid network inversely according to the change in downstream fluid resistance. When the soil in the irrigation area is generally dry, the opening degree of each terminal humidity response unit 2 is large, resulting in low downstream fluid resistance. The system hydraulic distribution unit 1 increases the total inflow to meet the overall demand. When the soil moisture in some areas increases, the opening degree of the terminal humidity response unit 2 in that area decreases, causing the fluid resistance on the irrigation branch 20 where it is located to increase. The fluid resistance on all irrigation branch 20 is superimposed in parallel, resulting in a corresponding increase in downstream fluid resistance. The system hydraulic distribution unit 1 then reduces the total inflow to avoid water waste. During the dynamic process of total flow regulation, since the flow distribution of the parallel-connected irrigation branches 20 tends to follow the path with less resistance, when the system hydraulic distribution unit 1 adjusts the total flow in response to changes in total resistance, the irrigation branch 20 with relatively lower real-time fluid resistance—that is, the irrigation branch 20 with a larger opening of the terminal humidity response unit 2 and drier soil—will receive a larger proportion of the increased inflow, allowing the water flow to prioritize areas with more urgent water needs. The two-stage adaptive drip irrigation system of this invention achieves adaptive regulation of global water volume and optimization of regional flow through its mechanical structure, requiring no external energy or control signals, and is suitable for remote agricultural areas lacking power and communication infrastructure.

[0037] It is worth noting that the control logic of the two-stage adaptive drip irrigation system of this invention enables the terminal humidity response unit 2 to adjust the real-time fluid resistance on the irrigation branch 20 according to the local soil moisture, and the system hydraulic distribution unit 1 to dynamically adjust the total inflow based on the total resistance. This automatically reduces or even stops water supply when soil moisture is high, avoiding over-irrigation and achieving precise water conservation. Simultaneously, through the inverse proportional adjustment mechanism of the system hydraulic distribution unit 1, the total system flow and pressure can be stabilized when the resistance of some irrigation branches 20 changes, avoiding the impact of sudden pressure changes on the irrigation fluid network and improving system reliability.

[0038] For example, multiple main water supply lines 10 can be connected in parallel to a water source, with a water pump and pressure control element connected to the water source. Alternatively, each main water supply line 10 can be connected to a water source in the same manner, thereby achieving interconnection of multiple two-stage adaptive drip irrigation systems of the present invention. Furthermore, to obtain more stable operating performance, a pressure stabilizing valve for stabilizing the inlet pressure can be installed on the main water supply line 10 upstream of the system hydraulic distribution unit 1, and check valves can be installed on some or all of the irrigation branch lines 20.

[0039] It should be understood that, within the scope of this invention, there are also implementations where multiple terminal humidity response units 2 are arranged in series on the same irrigation branch 20. In this series arrangement, the actual outflow of each terminal humidity response unit 2 located at different positions on the series branch will be affected by the decrease in upstream pressure due to friction loss. However, the total outflow of the series branch as a whole is still determined by the real-time fluid resistance of all the terminal humidity response units 2 connected in series on the branch; the resistance of this series branch as a whole still constitutes the total downstream fluid resistance together with the resistance of other parallel branches, which is then responded to by the system hydraulic distribution unit 1 to achieve total flow regulation. Therefore, even if multiple terminal humidity response units 2 are arranged in series on individual irrigation branches 20, it should be considered within the reasonable variations covered by this invention.

[0040] In this embodiment, the system hydraulic distribution unit 1 includes a venturi tube 11 and a hydraulic feedback regulating valve 12. The venturi tube 11 is connected in series to the main water supply pipeline 10, and a pressure tap is provided at the throat of the venturi tube 11. The hydraulic feedback regulating valve 12 is located upstream of the venturi tube 11, and the opening degree of the hydraulic feedback regulating valve 12 is controlled by the throat pressure of the venturi tube 11 obtained through the pressure tap.

[0041] It should be understood that the cone angle of contraction and expansion of the Venturi tube 11, and the ratio of throat diameter to pipe diameter, can be optimized and adjusted according to different system flow and pressure designs. The relevant parameter settings can also be achieved by referring to existing related technologies, so they are not elaborated here.

[0042] In one optional embodiment, the hydraulic feedback regulating valve 12 includes: a valve body 121, a diaphragm 122, a valve core 123, and an elastic member 124; wherein, the diaphragm 122 is disposed within the valve body 121 and divides the inner cavity of the valve body 121 into an upper control cavity and a lower flow cavity that are isolated from each other, and the upper control cavity is connected to a pressure tap; the valve core 123 is connected to the diaphragm 122 and is driven by the diaphragm 122 to change the flow area of ​​the lower flow cavity, thereby changing the opening degree of the hydraulic feedback regulating valve 12; the elastic member 124 is connected to the valve core 123 and is used to provide the valve core 123 with an elastic force that tends to increase the flow area of ​​the lower flow cavity, thereby realizing the automatic reset of the valve core 123.

[0043] Preferably, the elastic member 124 can be an elastic element that can provide a restoring force, such as a spring or a rubber elastic element.

[0044] Preferably, the diaphragm 122 and the valve core 123 are connected by a rigid connector, and an adjusting spring is also sleeved on the rigid connector. By adjusting the elastic force of the adjusting spring and working together with the elastic member 124, the opening degree of the hydraulic feedback regulating valve 12 can be controlled.

[0045] The system hydraulic distribution unit 1 includes a venturi tube 11 and a hydraulic feedback regulating valve 12. Its principle is that changes in downstream fluid resistance directly alter the flow rate through the venturi tube 11, thereby causing a corresponding change in its throat pressure. The throat pressure of the venturi tube 11 increases with increasing downstream fluid resistance and decreases with decreasing downstream fluid resistance. Based on this, the throat pressure serves as a control signal. The hydraulic feedback regulating valve 12 is configured to decrease its opening in response to an increase in throat pressure and increase its opening in response to a decrease in throat pressure. Specifically, when increased downstream resistance leads to an increase in the throat pressure of the venturi tube 11, the opening of the hydraulic feedback regulating valve 12 decreases, thereby reducing the total influent flow rate; conversely, the opening increases, increasing the total influent flow rate. This process is entirely hydraulically automated, with rapid and reliable response.

[0046] In this embodiment, each terminal humidity response unit 2 includes a drip irrigation head housing 21, a humidity sensing drive 22, and a flow regulating valve 23. The drip irrigation head housing 21 is provided with a water inlet, a water outlet, and a permeable section 211. The water inlet is connected to the irrigation branch 20, and the water inlet and the water outlet are connected through a flow cavity. The humidity sensing drive 22 is disposed in the drip irrigation head housing 21 near the permeable section 211. The humidity sensing drive 22 is made of a humidity-sensitive material, and the volume of the humidity-sensitive material can reversibly change with the local soil moisture.

[0047] Specifically, the volume of the humidity-sensitive material increases with increasing local soil moisture and decreases with decreasing local soil moisture. A flow regulating valve 23 is located within the flow cavity between the inlet and outlet infiltration ports and is connected to a humidity-sensing drive unit 22. This valve changes the flow area of ​​the flow regulating valve 23 based on the volume change of the humidity-sensing drive unit 22, thereby adjusting the flow capacity of the terminal humidity response unit 2. Preferably, multiple flow cavities can be arranged in parallel, such as a first cavity near the inlet, a second cavity connected to the first cavity through multiple through-holes, and a third cavity isolated by the flow regulating valve 23 and whose flow area with the second cavity can be controlled. The outlet infiltration port can be located in the third cavity. This arrangement achieves both cavity connectivity and buffering through the multiple cavity structure, making the flow capacity adjustment process of the terminal humidity response unit 2 more stable.

[0048] In an optional embodiment, the permeable portion 211 is provided with a porous structure for water to pass through, and the humidity sensing drive 22 is disposed inside the drip head housing 21 and exchanges moisture with the external environment (such as the local soil environment where it is located) through the porous structure of the permeable portion 211.

[0049] For example, the porous structure on the permeable section 211 allows water vapor to pass through but blocks soil solid particles. This porous structure ensures both the sensitivity and accuracy of humidity sensing while effectively preventing soil particles from contaminating and clogging the internal sensitive elements, thus ensuring the long-term reliable operation of the terminal humidity response unit 2. Preferably, the permeable section 211 can be made of porous ceramic.

[0050] In an optional embodiment, the flow regulating valve 23 includes a conical valve plug 231 and a valve seat 232 that cooperates with the conical valve plug 231; the humidity sensing drive 22 is connected to the conical valve plug 231 and drives the conical valve plug 231 to move axially relative to the valve seat 232 to change the area of ​​the annular flow gap between the conical valve plug 231 and the valve seat 232, thereby changing its flow capacity.

[0051] Preferably, the humidity-sensitive material may be one or more combinations of polyacrylamide hydrogel, polyvinyl alcohol hydrogel, or polyacrylate copolymer hydrogel, but is not limited thereto. It should be understood that the selection of the humidity-sensitive material must satisfy the characteristic of its volume changing with humidity, but its specific expansion rate, response speed, and other parameters can be selected and adjusted according to the actual application scenario through conventional experiments or existing technical data. The specific selection and performance optimization of the material do not affect the realization of this invention, and therefore are not elaborated upon.

[0052] For example, the flow regulating valve 23 may also adopt a valve core 123 structure that can be relatively displaced to linearly change the flow area, such as a flat valve or a ball valve.

[0053] The flow capacity of the terminal humidity response unit 2 is reflected in the outflow rate of the irrigation branch 20 it is located in. When the local soil moisture of the terminal humidity response unit 2 increases, it exchanges moisture with the external environment through the porous structure of the permeable part 211, which increases the volume of the humidity-sensitive material and decreases the area of ​​the annular flow gap between the conical valve plug 231 and the valve seat 232, thereby reducing the flow capacity of the flow regulating valve 23. As a result, the outflow rate of the irrigation branch 20 decreases as the local soil moisture increases. When the local soil moisture of the terminal humidity response unit 2 decreases, it exchanges moisture with the external environment through the porous structure of the permeable part 211, which decreases the volume of the humidity-sensitive material. This increases the area of ​​the annular flow gap between the conical valve plug 231 and the valve seat 232, thereby increasing the flow capacity of the flow regulating valve 23. As a result, the outflow rate of the irrigation branch 20 increases as the local soil moisture decreases.

[0054] Specifically, each terminal humidity response unit 2 on each irrigation branch 20 includes a humidity sensing actuator 22 made of humidity-sensitive material and a flow regulating valve 23 connected thereto. The humidity sensing actuator 22 exchanges moisture with the environment through a permeable portion 211 on the drip head housing 21. When the local soil moisture in the area where the terminal humidity response unit 2 is located increases, water vapor in the environment causes the humidity-sensitive material to absorb water and expand through the permeable portion 211, thereby pushing the conical valve plug 231 to move, reducing the annular flow gap between it and the valve seat 232, thus reducing the water flow rate of the terminal. Conversely, when the soil moisture decreases, the humidity-sensitive material loses water and shrinks, and the valve opening of the flow regulating valve 23 increases to increase the water flow rate. With this structure, each terminal humidity response unit 2 can independently adjust its own water output according to changes in soil moisture, realizing localized on-demand irrigation.

[0055] Example 2

[0056] like Figure 8 As shown, Figure 8 This is a flowchart of a two-stage adaptive irrigation method provided in an embodiment of the present invention.

[0057] In this embodiment, the two-stage adaptive drip irrigation method adopts the two-stage adaptive drip irrigation system of Embodiment 1, and the method includes:

[0058] Step 1: The terminal humidity response units on multiple irrigation branches connected in parallel sense the local soil moisture and adjust the overcurrent capacity of each terminal humidity response unit.

[0059] Step 2: By adjusting the overcurrent capacity of each terminal humidity response unit, the real-time fluid resistance of the irrigation branch is changed. The real-time fluid resistance is used to characterize the water demand status of the irrigation branch.

[0060] Step 3: The real-time fluid resistance changes of multiple irrigation branches cause changes in the downstream fluid resistance of the hydraulic distribution unit set in the main water supply pipeline system. The downstream fluid resistance is used to characterize the overall water demand status of the irrigation fluid network.

[0061] Step 4: The total inflow of the irrigation fluid network is adjusted inversely according to the change in downstream fluid resistance through the system hydraulic distribution unit, and the real-time flow of each irrigation branch is adjusted according to the real-time fluid resistance of multiple irrigation branches.

[0062] In an optional implementation, step 4 specifically includes: when the downstream fluid resistance changes, the flow rate through the system hydraulic distribution unit is changed, the throat pressure of the system hydraulic distribution unit changes, and the change in throat pressure drives the hydraulic feedback regulating valve to change its opening, thereby regulating the total inflow of the irrigation fluid network; at the same time, the real-time flow rate of each irrigation branch is adjusted according to the real-time fluid resistance of multiple irrigation branches.

[0063] It should be understood that the method provided in Embodiment 2 of the present invention can employ the two-stage adaptive drip irrigation system of Embodiment 1, and therefore has similar beneficial effects to the two-stage adaptive drip irrigation system of Embodiment 1. For technical details not disclosed in the method embodiments of the present invention, please refer to the description of the system embodiments for understanding.

[0064] Example 3

[0065] To enable those skilled in the art to fully understand and implement this invention, the specific implementation principle of this invention will be further explained below in conjunction with a specific application scenario.

[0066] This invention provides a two-stage adaptive drip irrigation system, in which multiple irrigation branches 20 are connected in parallel downstream of the main water supply line 10, forming an irrigation fluid network.

[0067] The system hydraulic distribution unit 1 is connected in series in the main water supply line 10, and includes a venturi tube 11 and a hydraulic feedback regulating valve 12. The venturi tube 11 is connected in series to the section of the main water supply line 10, and its diameter changes to form a throat, on which a pressure tap is opened. The hydraulic feedback regulating valve 12 is installed on the main water supply line 10 upstream of the venturi tube 11. The specific structure of the hydraulic feedback regulating valve 12 is as follows. Figure 3 and Figure 4 As shown, it includes a valve body 121, and a diaphragm 122 is disposed inside the valve body 121. The diaphragm 122 divides the inner cavity of the valve body 121 into an upper control cavity and a lower flow cavity. The upper control cavity is connected to the pressure tap of the throat of the venturi tube 11 through a pressure guide tube. The upper end of the valve core 123 is connected to the center of the diaphragm 122 through a rigid transmission member. The lower end of the valve core 123 extends to the lower flow cavity, and its end and the valve body 121 form a valve port structure. An elastic member 124, such as a helical spring, is sleeved on the outside of the valve core 123 to provide it with an upward biasing force that tends to open the valve port.

[0068] Terminal humidity response units 2 are installed on each irrigation branch 20, with at least one unit. Their specific structure is as follows: Figure 5 and Figure 6As shown, each terminal humidity response unit 2 includes a drip head housing 21, which has an inlet port for connecting to the irrigation branch 20 and an outlet port for infiltrating water into the soil, forming a flow cavity between the inlet port and the outlet port. The side wall of the housing 21 has a permeable portion 211 made of porous ceramic material. Inside the drip head housing 21, near the permeable portion 211, a humidity sensing actuator 22 is provided, made of a humidity-sensitive material whose volume can reversibly change with ambient humidity. A flow regulating valve 23 is disposed within the flow cavity, including a valve seat 232 and a conical valve plug 231. The conical valve plug 231 is disposed on the humidity sensing actuator 22 and can move axially under the drive of the humidity sensing actuator 22.

[0069] The working process and principle of the two-stage adaptive drip irrigation system of the present invention are as follows, and can be combined with... Figure 7 To understand:

[0070] First, in a single irrigation branch 20, the real-time fluid resistance is mainly determined by the flow capacity of one or more terminal humidity response units 2 installed on the branch. When the flow capacity of the terminal humidity response unit 2 is large (i.e., the valve opening is large), the branch has a small obstruction effect on the water flow and the real-time fluid resistance is small; conversely, if the flow capacity is small, the real-time fluid resistance is large. According to the principle of fluid mechanics, under a certain driving pressure, the flow rate through the branch is inversely proportional to its fluid resistance.

[0071] Secondly, all irrigation branches 20 are connected in parallel. In the parallel network, the total downstream fluid resistance of the system is determined by the real-time fluid resistance of each branch, and the total resistance is less than the independent resistance of any branch. The total inflow of the system is equal to the sum of the flow of each branch. The flow allocated to each branch is inversely proportional to its own real-time fluid resistance. That is, the branch with the smaller resistance receives a larger share of the flow. The principle is the inherent distribution characteristic of the parallel network: the smaller the resistance, the more the flow is distributed.

[0072] Finally, the core component of the system's hydraulic distribution unit 1, the Venturi tube 11, operates based on Bernoulli's equation. When water flows through the Venturi tube 11, the fluid velocity reaches its maximum at the point where the cross-sectional area of ​​the throat is smallest, while the static pressure of the fluid (i.e., the throat pressure) drops to its minimum. The greater the volumetric flow rate through the Venturi tube 11, the greater the throat velocity and the lower the throat pressure; conversely, the smaller the total flow rate, the higher the throat pressure. Therefore, the throat pressure becomes an indirect signal reflecting the downstream total fluid resistance: a smaller downstream total resistance results in a larger total flow demand and a lower throat pressure; a larger downstream total resistance results in a smaller total flow demand and a higher throat pressure. This allows the system's hydraulic distribution unit 1 to inversely adjust the total inflow of the irrigation fluid network according to changes in downstream fluid resistance.

[0073] Based on this, in the initial state or when the irrigated area is generally dry, the local soil moisture of each terminal humidity response unit 2 is low. Moisture in the environment is exchanged with the humidity sensing drive unit 22 through the permeable part 211, keeping the humidity-sensitive material in a relatively dry and contracted state. At this time, the conical valve plug 231 experiences less upward thrust, the annular flow gap between the conical valve plug 231 and the valve seat 232 is larger, the flow capacity of the terminal humidity response unit 2 is large, and the outflow rate is large. Because the opening degree of all terminal humidity response units 2 is large, the fluid resistance of each irrigation branch 20 is small, and the total downstream fluid resistance formed after their parallel connection is also small.

[0074] The low downstream total fluid resistance means a large overall flow demand through the Venturi tube 11. According to Bernoulli's principle, the flow velocity and static pressure at the throat of the Venturi tube 11 are high at this time. This low pressure signal is transmitted to the upper control chamber of the hydraulic feedback regulating valve 12 through the pressure guide tube, acting on the diaphragm 122. The lower chamber pressure cannot completely overcome the biasing force of the elastic member 124, so the valve core 123 is pushed upward, the opening of the hydraulic feedback regulating valve 12 is large, and the total influent flow of the system is kept at a high level to meet the irrigation needs of a large area.

[0075] When one or more areas are fully irrigated, the local soil moisture increases. The terminal humidity response unit 2 in that area senses the increased humidity through the permeable part 211. The sensitive material in the humidity sensing drive 22 absorbs water and expands, increasing its volume. The force generated by the expansion pushes the conical valve plug 231 upward, reducing the annular flow gap between the conical valve plug 231 and the valve seat 232, thereby reducing the flow capacity and water output of the terminal humidity response unit 2.

[0076] The reduced water output of the terminal humidity response unit 2 directly leads to an increase in the fluid resistance of the irrigation branch 20 it is located in. Since multiple irrigation branches 20 are connected in parallel, an increase in the resistance of any branch will lead to an increase in the total fluid resistance downstream. The increase in total resistance causes a tendency for the total flow through the Venturi tube 11 to decrease, which in turn leads to a decrease in the flow velocity at its throat and an increase in static pressure.

[0077] The increased throat pressure signal is then transmitted to the hydraulic feedback regulating valve 12, increasing the force acting on the diaphragm 122. When this force exceeds the reset elastic force of the elastic member 124, the diaphragm 122 drives the valve core 123 to move downward, thereby reducing the opening of the hydraulic feedback regulating valve 12 and automatically reducing the total inlet flow of the system.

[0078] During the dynamic process of reducing the total inflow, the water flow will automatically tend to pass through the path with less resistance according to the hydraulic characteristics of the parallel pipe network. At this time, the irrigation branches 20 with drier soil, larger opening of terminal humidity response unit 2, and thus smaller branch resistance will receive a larger proportion of the total water volume allocation compared to the branches that are already wet and have increased resistance. This process realizes the automatic priority allocation of water flow from wet areas to dry areas.

[0079] Thus, the two-stage adaptive drip irrigation system of this invention achieves local soil moisture sensing and corresponding flow fine-tuning through the terminal humidity response unit 2, and adaptive adjustment of the global water inflow through the system hydraulic distribution unit 1. Utilizing the inherent fluid distribution characteristics of the parallel pipeline network, it automatically optimizes water distribution to areas with more urgent water needs during changes in total flow. The entire system operates in a closed loop based on hydraulic feedback and the material's wet expansion characteristics, requiring no external power supply or electronic controller, thus possessing passive operation characteristics and being suitable for remote agricultural areas with weak power and communication infrastructure.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0081] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A two-stage adaptive drip irrigation system, characterized in that, Downstream of the main water supply pipeline, multiple irrigation branches are connected in parallel to form an irrigation fluid network. The system includes: a system hydraulic distribution unit and multiple terminal humidity response units. The system hydraulic distribution unit is installed in the main water supply pipeline. The system hydraulic distribution unit is used to adjust the total inflow of the irrigation fluid network according to the downstream fluid resistance. The system hydraulic distribution unit includes a venturi tube and a hydraulic feedback regulating valve. The venturi tube is connected in series in the main water supply pipeline, and the throat of the venturi tube is provided with a pressure tap. The hydraulic feedback regulating valve is installed upstream of the venturi tube, and the opening degree of the hydraulic feedback regulating valve is controlled by the throat pressure of the venturi tube obtained through the pressure tap. The throat pressure increases with increasing downstream fluid resistance and decreases with decreasing downstream fluid resistance; the hydraulic feedback regulating valve is configured to decrease its opening in response to an increase in throat pressure and increase its opening in response to a decrease in throat pressure. At least one terminal humidity response unit is provided on each of the irrigation branches, and each terminal humidity response unit is used to adjust its own flow capacity according to the local soil moisture where it is located. Among them, multiple terminal humidity response units on the same irrigation branch constitute the real-time fluid resistance of the irrigation branch. The real-time fluid resistances of all irrigation branches are superimposed in parallel to constitute the downstream fluid resistance. The system hydraulic distribution unit is configured to adjust the total inflow of the irrigation fluid network inversely according to the change of the downstream fluid resistance. Each of the terminal humidity response units includes a drip head housing, a humidity sensing drive, and a flow regulating valve; The drip irrigation head housing is provided with a water inlet, a water outlet and a moisture permeation section. The water inlet is connected to the irrigation branch, and the water inlet and the water outlet are connected through a flow cavity. The humidity sensing drive is located near the permeable part inside the drip head housing. The humidity sensing drive is made of a humidity-sensitive material, and the volume of the humidity-sensitive material can reversibly change with the local soil moisture. The flow regulating valve is disposed in the flow cavity between the water inlet and the water outlet, and is connected to the humidity sensing drive; the flow regulating valve is used to change its flow area according to the volume change of the humidity sensing drive, so as to adjust the flow capacity of the terminal humidity response unit.

2. The two-stage adaptive drip irrigation system according to claim 1, characterized in that, The hydraulic feedback regulating valve includes: a valve body, a diaphragm, a valve core, and an elastic component; The diaphragm is disposed within the valve body and divides the inner cavity of the valve body into an upper control cavity and a lower flow cavity that are isolated from each other. The upper control cavity is connected to the pressure tap. The valve core is connected to the diaphragm and is driven by the diaphragm to change the flow area of ​​the lower flow cavity, thereby changing the opening degree of the hydraulic feedback regulating valve. The elastic member is connected to the valve core and is used to provide the valve core with an elastic force that tends to increase the flow area of ​​the lower flow cavity.

3. The two-stage adaptive drip irrigation system according to claim 1, characterized in that, The permeable section is provided with a porous structure for water to pass through, and the humidity sensing drive is disposed inside the drip head housing and exchanges moisture with the external environment through the porous structure of the permeable section.

4. The two-stage adaptive drip irrigation system according to claim 3, characterized in that, The flow regulating valve includes a conical valve plug and a valve seat that mates with the conical valve plug; the humidity sensing drive is connected to the conical valve plug and drives the conical valve plug to move axially relative to the valve seat, thereby changing the area of ​​the annular flow gap between the conical valve plug and the valve seat, and thus changing the flow capacity of the flow regulating valve.

5. The two-stage adaptive drip irrigation system according to claim 4, characterized in that, The volume of the humidity-sensitive material increases with the increase of local soil moisture and decreases with the decrease of local soil moisture; the humidity-sensitive material is one or more of polyacrylamide hydrogel, polyvinyl alcohol hydrogel, or polyacrylate copolymer hydrogel.

6. The two-stage adaptive drip irrigation system according to claim 5, characterized in that, The overcurrent capacity of the terminal humidity response unit is expressed as the outflow rate of the irrigation branch it is located in. When the local soil moisture in the area where the terminal humidity response unit is located increases, the water exchange with the external environment is carried out through the porous structure of the permeable part, which increases the volume of the humidity-sensitive material and reduces the area of ​​the annular flow gap between the conical valve plug and the valve seat, thereby reducing the flow capacity of the flow regulating valve and thus reducing the outflow rate of the irrigation branch as the local soil moisture increases. When the local soil moisture decreases at the location of the terminal humidity response unit, moisture is exchanged with the external environment through the porous structure of the permeable part. The volume of the humidity-sensitive material decreases, which increases the area of ​​the annular flow gap between the conical valve plug and the valve seat, thereby improving the flow capacity of the flow regulating valve. Consequently, the outflow rate of the irrigation branch increases as the local soil moisture decreases.

7. A two-stage adaptive drip irrigation method, characterized in that, The method of using the two-stage adaptive drip irrigation system according to any one of claims 1 to 6 includes: Step 1: The terminal humidity response units on the multiple irrigation branches connected in parallel sense the local soil moisture and adjust the overcurrent capacity of each terminal humidity response unit. Step 2: By adjusting the overcurrent capacity of each terminal humidity response unit, the real-time fluid resistance of the irrigation branch is changed. The real-time fluid resistance is used to characterize the water demand status of the irrigation branch. Step 3: The real-time fluid resistance changes of the multiple irrigation branches cause changes in the downstream fluid resistance of the hydraulic distribution unit set in the main water supply pipeline system. The downstream fluid resistance is used to characterize the overall water demand status of the irrigation fluid network. Step 4: The total inflow rate of the irrigation fluid network is adjusted inversely according to the change in downstream fluid resistance by the system hydraulic distribution unit, and the real-time flow rate of each irrigation branch is adjusted according to the real-time fluid resistance of the multiple irrigation branches.

8. The two-stage adaptive drip irrigation method according to claim 7, characterized in that, Step 4 specifically includes: When the downstream fluid resistance changes, the flow rate through the system hydraulic distribution unit changes, and the throat pressure of the system hydraulic distribution unit changes. The change in throat pressure drives the hydraulic feedback regulating valve to change its opening, thereby regulating the total inflow rate of the irrigation fluid network. Simultaneously, the real-time flow rate of each irrigation branch is adjusted based on the real-time fluid resistance of the multiple irrigation branches.

Images