CN1239072C - Automatic drip irrigation flow rate control switch - Google Patents

Abstract

The invention relates to an automatic control switch device, in particular to a switch capable of automatically controlling drip irrigation flow according to soil moisture. It consists of a porous shell (1), water-absorbing material (5), elastic water pipe (3), and a limit piston (2). The porous shell (1) with one end open contains water-absorbing material (5), and the elastic water pipe (3) is bent into U-shaped structure, the bottom of the U-shaped structure is the pressure deformation end, which is in contact with the water-absorbing material (5), the inlet and outlet ends of the elastic water pipe (3) pass through the limit piston (2) and closely cooperate with it, the limit piston (2) Fit tightly with the porous shell (1). The invention has the function of self-adaptive and dynamic adjustment of the drip irrigation flow, does not need electric power to maintain the operation of the system, and has fast response speed, small size and low price, and is suitable for plant water saving in areas where water resources and power resources are relatively scarce Irrigation, crop cultivation, fluid control and desert control, etc.

Description

A drip irrigation flow automatic control switch

technical field

The invention relates to an automatic control switch device, in particular to a switch capable of automatically controlling drip irrigation flow according to soil moisture.

Background technique

There are three commonly used crop irrigation methods: artificial irrigation, ditch self-flow irrigation, and sprinkler irrigation, all of which have the disadvantage of serious waste of water resources. Most of the water seeps down along the soil gap, and only a small part is absorbed by the root system of the crops. . Especially in the case of increasingly tense water resources in our country, it is of great significance to save irrigation water and promote high-tech agriculture. Drip irrigation technology only slowly supplies water to the roots of crops, while the soil between crops remains dry; it can save water to the minimum, and the water resource utilization rate can be as high as 85% to 95%. However, the drip irrigation system usually uses devices such as humidity sensor, microcomputer control, and solenoid valve drive. The complicated equipment and expensive price greatly limit its popularization and application.

Chinese Invention Patent (Application No. 86207335, Publication No. CN86207335U, Publication Date November 7, 1987) discloses a soil drip irrigation switch, which consists of a soil negative pressure sensor and an elastic film flow control component, which is controlled by soil negative pressure. The negative pressure in the sensor is actuated to control the irrigation water supply channel; Chinese invention patent (patent number 88209217.0, announcement number CN2036345U, announcement date April 26, 1989) discloses an automatic drip irrigation dripper, which consists of a soil negative pressure tube and an elastic It is composed of a thin-film control flow valve, and the switch and opening degree of the flow control valve are controlled by the pressure in the soil negative pressure pipe; the above two patents use a soil negative pressure sensor made of porous ceramics, which has a complex structure and is inconvenient to operate.

Chinese invention patent (patent No. 89212164.5, announcement number CN2047479U, announcement date on November 15, 1989) discloses a kind of automatic plant drip irrigation device, comprises container, hose, valve and the dropper that can be inserted into soil conveniently, also has The diverter used to expand the drip irrigation area and the sensor that can automatically control the opening and closing of the dripper according to the growth needs of the plants, that is, the degree of dryness and humidity of the soil; Chinese invention patent (patent number 91231990.9, authorized announcement number CN2127242Y, announcement date February 24, 1993 Japan) discloses a drip irrigation device with automatic humidity control, which is composed of a cylindrical bracket connected to a cuboid aqueduct, a wooden expansion block inside the bracket, a spherical valve and a spring inside the aqueduct, and a diaphragm between the bracket and the aqueduct , using the principle of wood material expanding when wet and shrinking when drying, the valve is closed or opened, thereby controlling the flow of water in the pipeline; the above two patents both use wooden expansion blocks as the sensor driving material, and their expansion coefficient is only 2 %, and the expansion and shrinkage speed is slow, and it is easy to produce plastic deformation, resulting in dimensional instability.

Contents of the invention

The purpose of the present invention is to propose a drip irrigation flow automatic control switch that does not consume electric energy, which can automatically control the water consumption of crops according to the humidity of the soil, and achieve the water-stop effect through small force or displacement changes, and is sensitive to humidity, It has the characteristics of fast response to water stop and discharge.

Technical scheme of the present invention is:

An automatic control switch for drip irrigation flow, which is composed of a porous shell, water-absorbing material, elastic water pipe, and a limit piston. The porous shell with one end open is equipped with water-absorbing material, and the elastic water pipe is bent into a U-shaped structure. The bottom of the U-shaped structure is a pressure-deformed end , in contact with the water-absorbing material, the inlet and outlet ends of the elastic water pipe pass through the limit piston and closely cooperate with it, and the limit piston closely cooperates with the porous shell.

A limiting top plate is added between the water-absorbing material and the contact surface of the elastic water pipe.

A limit baffle is respectively provided on the left and right sides of the limit top plate.

The position-limiting top plate is a plexiglass plate or a plastic plate, which is bonded with a water-absorbing material.

The porous shell is a rigid shell made of clay, brick or plastic.

The limiting piston is a foam stopper, a rubber stopper or a cork stopper.

The limiting piston is inserted into the porous shell or is threadedly connected with the porous shell.

The elastic water tube is a silicone rubber tube or a latex tube.

The water-absorbing material is a high polymer water-absorbing material.

The high polymer water-absorbing material is one of polyacrylamide, polyvinyl alcohol, polyacrylic acid or its derivatives.

The principle of the invention is to use the reversible expansion and contraction characteristics of the water-absorbing high polymer material at different water contents to sense the change of soil water content, and to control the size and direction of the expansion pressure of the material through structural design, and to control the elasticity of the water pipe. The degree of deformation can achieve automatic control of drip irrigation flow. When the water in the soil is sufficient, the water-absorbing material expands and squeezes the water pipe to deform. Due to the reduction of the cross-sectional area of the water pipe, the passage of water flow is blocked to achieve the purpose of water stop. When water evaporation and crop absorption lead to insufficient soil moisture, the water-absorbing material will shrink correspondingly, and the water flow can flow out in time to supply water to the crops due to the reduced pressure of the bound water pipes. The behavior of the material in different environments is reversible, so the control switch can dynamically adjust the amount of drip irrigation according to the soil moisture.

The beneficial effects of the present invention are:

1. The present invention adopts high polymer water-absorbing material as the sensing element of soil humidity and the driving element of flow control, which has the reversible characteristics of rapid water absorption and drying shrinkage, and utilizes the reversible expansion and contraction of water-absorbing material at different water contents to achieve Flow control in elastic water pipes. When the soil moisture is sufficient, the material absorbs water and expands by 40% to 60% in a few seconds, and the expansion pressure generated during the expansion process can compress the elastic water pipe to deform and stop the water flow; when the soil is dry, the material has rapid syneresis Under the action of the hydrostatic pressure and the elastic recovery force of the water pipe, the water in the pipe flows and starts to supply water to the soil, so as to achieve the purpose of automatically controlling the drip irrigation flow according to the soil moisture.

2. The present invention can automatically adjust the drip irrigation flow according to the change of soil humidity. It does not use electricity as an energy source, and uses the reversible change of the volume of the water-absorbing material at different water contents to realize the functions of humidity sensing and drive control. The water pipes of its water supply system It is an elastic rubber tube, which forms an extruded and deformed structure in the device. The degree of deformation and shape can be adjusted within a certain range. Through the design of the extruded and deformed structure of the elastic water tube, the device has the characteristics of fast response and remarkable control effect. When the water-absorbing material expands, it compresses the top of the elastically deformed water pipe, and uses the different bending degrees of different parts of the water pipe to achieve the purpose of rapid water stop. The response time of the switch control can be adjusted and controlled within 1 minute to 24 hours. The greatest advantage of the invention is that it has the function of self-adaptive and dynamic adjustment of the drip irrigation flow, and does not require electricity to maintain the operation of the system; and it has fast response speed, small size and low price, and can be used in areas where water resources and power resources are relatively scarce. .

3. The present invention uses rigid porous water-absorbing materials (such as pottery clay, bricks, etc.) as the shell of the device. Because it contains many micropores, the moisture in the soil can freely enter and exit the device; in addition, the rigid shell can stop the volume change of the soil on the one hand. The extrusion effect on the device maintains the integrity of the structure; on the other hand, it limits the outward expansion of the water-absorbing material when it absorbs water and expands, forcing the water-absorbing material to generate inward pressure when it expands.

4. The present invention has a wide range of applications, and can be applied to plant water-saving irrigation, crop cultivation, fluid control and desert control in areas where water resources and power resources are relatively scarce.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention.

Figure 2 is a graph showing the relationship between drip irrigation flow and time.

Detailed ways

The structure diagram of the present invention is shown in Fig. 1. The device is composed of a porous shell 1, a water-absorbing material 5, a limit top plate 4, an elastic water pipe 3, and a limit piston 2. The porous shell 1 with one end open is equipped with a water-absorbing material 5, and the top of the water-absorbing material 5 is provided with a limit top plate 4, and the elastic water pipe 3 Bend into a U-shaped structure, the bottom of the U-shaped structure is the pressure deformation end, which is in contact with the limit top plate 4, the inlet and outlet ends of the elastic water pipe 3 pass through the limit piston 2 and closely cooperate with it, the limit piston 2 and the porous shell 1 are closely matched, and the compressed deformation end is triangular as shown in Figure 1 after being subjected to the pressure of the limiting top plate 4. Arrow A is the water inlet and B is the water outlet. In the figure, the porous shell 1 is a rigid shell made of pottery clay. Because it contains many micropores, the moisture in the soil can freely enter and exit the device; on the one hand, the rigid shell can prevent the extrusion of the device when the volume of the soil changes, and maintain The integrity of the structure; on the other hand, it limits the outward expansion of the water-absorbent material 5 when it absorbs water and expands, and forces the water-absorbent material to generate inward pressure when it expands. In the figure, the limit piston 2 is a limit piston made of foam, which is inserted into the porous shell 1. On the one hand, it is used to fix the water inlet pipe and the water outlet pipe to maintain a specific extrusion deformation structure. On the other hand, the limit piston 2 is compatible with the rigid The shell 1 can fit very closely and can be adjusted to move relatively, which is used to adjust the deformation degree of the water pipe under pressure to control the amount and speed of water supply; the elastic water pipe 3 in the figure is a highly elastic silicone rubber water pipe, which can produce great deformation Without fatigue and permanent deformation, the elastic rubber water pipe is bent into a pressure deformation structure as shown in the figure, and the degree of deformation of the water pipe can be controlled by properly adjusting the position of the limit piston 2, which can be controlled under a small pressure and Sensitive control of water volume is realized under displacement changes. When the environment is dry, the water-absorbing material 5 shrinks, and the elastic recovery force and hydrostatic pressure of the rubber hose can make the deformed water pipe return to its original shape and make the waterway unimpeded; the limiting top plate 4 in the figure is a limiting top plate made of plexiglass. The water-absorbing material 5 is bonded together, and its function is to make the large-area expansion pressure produced by the expansion of the water-absorbing material 5 concentrate on the elastic rubber water pipe to increase the pressure on the water pipe; A limit baffle 41 is to keep the water pipe 3 and the water-absorbing material 5 in a vertical state all the time, so as to prevent inclination and eccentric instability when the water pipe is deformed under pressure; the water-absorbing material 5 in the figure is a high polymer water-absorbing material, and the high The polymer water-absorbing material is one of polyacrylamide, polyvinyl alcohol, polyacrylic acid or its derivatives. In this embodiment, porous polyacrylamide gel is used, which is prepared in the prior art. Pore-forming agents such as (CaCO ₃ ) and Mix the above-mentioned gel monomers, form a gel body by chemical cross-linking, and then soak in a solvent (such as hydrochloric acid), the pore-forming agent is precipitated, and a gel with a porous structure is formed, which has the reversible characteristics of rapid water absorption and drying shrinkage .

Connect the water inlet pipe to the water source (hydrostatic pressure is 1m), adjust the position of the limit piston 2 in dry conditions to control the drip irrigation flow rate at 30-40 drops/min (about 4mL/min), and bury the device in sandy soil , the water from the outlet pipe flows into the soil. As the soil moisture increases, part of the water will enter the device through the pores of the rigid clay shell 1, and the volume of the water-absorbing material 5 will expand rapidly. Due to the limitation of the size of the shell, the water-absorbing material can only expand to the inside of the device. The limit top plate 4 compresses the elastic rubber water pipe 3 to deform, automatically blocks the water flow, and stops the drip irrigation. When the soil is dry, the moisture in the device diffuses outwards through the pores, and the volume of the water-absorbing material 5 shrinks reversibly. As the pressure acting on the water pipe decreases, the water pipe returns to its original state under the action of the elastic water pipe’s restoring force and hydrostatic pressure. In the original shape, the waterway continued to flow smoothly and began to enter the state of drip irrigation.

Figure 2 is the experimental data of the automatic control of the flow rate under different humidity conditions after the device is buried in the soil. When the drip irrigation flow rate is 0 drops/min, in order to accelerate the dehydration process, the wet soil is air-dried until the drip irrigation flow rate is 30- Stop air drying at 40 drops/minute, and it can be seen that the device has the function of automatically controlling the drip irrigation flow according to the change of soil moisture.

The position-limiting top plate 4 of the present invention can be a plastic plate; the porous shell 1 can be a rigid shell made of brick or plastic; the position-limiting piston 2 can be a rubber stopper or a cork stopper; the position-limiting piston 2 can be It is connected with the porous shell 1 through threads; the elastic water pipe 3 can be a latex pipe.

Claims (6)

1. An automatic drip irrigation flow control switch, characterized in that: it is composed of a porous shell (1), water-absorbing material (5), elastic water pipe (3), and a limit piston (2), and the porous shell (1) with one end open There is a water-absorbing material (5), and the elastic water pipe (3) is bent into a U-shaped structure. The bottom of the U-shaped structure is a pressure-deformed end, which is in contact with the water-absorbing material (5). The inlet and outlet ends of the elastic water pipe (3) pass through the limit piston (2) and closely cooperate with it, the limit piston (2) is closely matched with the porous shell (1); a limit top plate (4) is added between the contact surface of the water-absorbing material (5) and the elastic water pipe (3); A limit baffle (41) is respectively provided on the left and right sides of the limit top plate (4); the water-absorbing material (5) is one of polymer water-absorbing materials polyacrylamide, polyvinyl alcohol, polyacrylic acid or derivatives thereof. thing. 2. The drip irrigation flow automatic control switch according to claim 1, characterized in that: the limiting top plate (4) is a plexiglass plate or a plastic plate, which is bonded to the water-absorbing material (5). 3. The drip irrigation flow automatic control switch according to claim 1, characterized in that: the porous shell (1) is a rigid shell made of clay, brick or plastic. 4. The drip irrigation flow automatic control switch according to claim 1, characterized in that: the limit piston (2) is a foam stopper, a rubber stopper or a cork stopper. 5. The drip irrigation flow automatic control switch according to claim 1, characterized in that: the limit piston (2) is inserted into the porous casing (1) or is threadedly connected with the porous casing (1). 6. The drip irrigation flow automatic control switch according to claim 1, characterized in that: the elastic water pipe (3) is a silicon rubber pipe or a latex pipe.

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