WO2017203530A1 - Autonomic drip irrigation device exploiting hydroelectric power - Google Patents

Abstract

Drip irrigation units that generate hydroelectric power from the line pressure using an impulse turbine are described. The energy generated may be used (for instance) to operate automatic irrigation control based on moisture sensors in communication with the units, or other purposes for example, field lighting, speaker power, or the like. The sensing and actuation functions may be separated, such that two different units are supplied, one being a sensing unit with hydroelectric generator, and the other being an actuation unit with hydroelectric generator, and these may be linked by wireless means such that the actuation is performed based on data from one or more sensing units. The use of wireless communications also allows for central control when desired. For instance when it is known that rain is on the way, a general command to stop irrigation for all units (regardless of moisture) may be supplied, or if a particularly hot day is anticipated, a general command to open all valves (again regardless of moisture) may be activated in the early morning.

Description

Autonomic drip irrigation device exploiting hydroelectric power

BACKGROUND

Drip irrigation devices are now commonplace, having the advantage over non-drip irrigation that the flow rate is reduced to be closer to the actual plant requirements, and that this rate can be made independent of the water pressure. Furthermore the irrigation is fed either to the soil surface or directly onto the plant's root zone, delivering water directly to where it is most useful. This method may be used to minimize evaporation and watering of irrelevant areas. Generally the control over the irrigation lines is made from a central valve, and thus whether a particular plant needs or doesn't need water is not taken into account; rather all the plants on the line are treated as one. This is somewhat suboptimal since in practice even on relatively uniform fields, there are local variations in topography, soil composition, drainage, and plant morphology that will tend to change the local needs , either greater or less than the field average. Thus in many cases one will be over- or under- watering large areas of the field, even if the overall average irrigation is spot-on.

Systems and methods have been developed for more localized irrigation control, generally involving the use of sensors to determine the moisture level of the soil, and valves or other actuators adapted to allow or stop the flow of water to the plant. One obvious drawback of these systems is that insofar as they require electricity to operate, they will of necessity require an electrical power source, be it a dedicated power line, solar electrical source, or the like. Each of these carries drawbacks; an electrical line is prone to being cut in the inimical conditions of an agricultural field (where for example tractors with rotary tillers may be routinely employed to till the earth to some depth) , while solar systems may be delicate, expensive, and will not deliver power in darkness (which may in some cases be ideal irrigation conditions) . The changing environment associated with the growing of plants, may cover up the solar panels with time.

The use of a hydroelectric turbine may therefore be considered for such applications. Such turbines come in two main varieties: reaction turbines and impulse turbines.

Reaction turbines are acted on by water, which changes pressure as it moves through the turbine and gives up its energy. They must be encased to contain the water pressure (or suction) , or they must be fully submerged in the water flow.

The flow rates involved are generally large, and such turbines are largely used in dams and large power plants.

Impulse turbines change the velocity of a water jet. A nozzle converts the water's pressure to kinetic energy by forming a jet of high-velocity water. The jet pushes on the turbine's curved blades which changes the direction of the flow. The resulting change in momentum (impulse) causes a force on the turbine blades. Since the turbine is spinning, the force acts through a distance (work) and the diverted water flow is left with diminished energy. An impulse turbine is one which the pressure of the fluid flowing over the rotor blades is constant and all the work output is due to the change in kinetic energy of the fluid.

Drip irrigation is a form of irrigation that allows the water to slowly drip out with a minimal kinetic energy from the high pressure water source pipe, to an atmospheric environment, through emitters or drippers. The emitters or drippers normally produce very low water flow rates around few liters per hour. The limited flow rates and the diminishing of the kinetic energy of the water associated with the drip irrigation methodology, makes the impulse turbine the only possible and practical option for obtaining an efficient extraction of hydroelectric power is such low flow rates.

All of the prior art turbines in irrigation devices are used for applications with flow rates which are at least order of magnitude larger than is normally used in emitters or drippers and are of the reaction turbine variety; US9332696 provides a sprinkler control irrigation unit having means for generating electrical power throught the flow of water. However the vertical turbines used are reaction turbines. Similarly,

US2016083937 provides a microturbine for powering the solenoid valve , the turbine however again being a reaction turbine.

Likewise US2015053786 and US2014298719 provide immersed turbines that necessarily are reaction and not impulse turbines.

There is therefore a long-felt need for a locally controlled drip irrigation system with a steady and constant power source using an impulse as an alternative power-harvesting mechanism, which has been hitherto unmet. SUMMARY

The invention comprises individual drip irrigation control units that exploit the water pressure in the drip irrigation line to generate electrical energy. The water is run past an impulse turbine, which unlike the more commonly used immersion turbines, can extract nearly all of the energy potential in the

pressurized water flow. This turbine runs a generator for electricity generation, and this electrical power is used to run the sensing and actuation circuits, any surplus being stored in a battery or capacitor. The sensing and actuation functions may be separated, such that two different units are supplied, one being a sensing unit with hydroelectric generator, and the other being an actuation unit with hydroelectric generator, and these may be linked by wireless means such that the actuation is performed based on data from one or more sensing units. The use of wireless communications also allows for central control when desired. For instance when it is known that rain is on the way, a general command to stop irrigation for all units

(regardless of moisture) may be supplied, or if a particularly hot day is anticipated, a general command to open all valves (again regardless of moisture) may be activated in the early morning .

It is within provision of the invention that the hydroelectric power generation from irrigation using an impulse turbine be used for other purposes than sensing or irrigation control; for example, field lighting, speaker power, or any other electrical load maybe powered using the system of hydroelectric power generation from irrigation water using an impulse turbine.

Proximity sensors, movement sensors, and the like may also all be powered in this way, allowing for perimeter control (for instance) over large distances without the need to run

electrical wiring. Communications means may be powered, allowing for instance a mesh network to be operated that provides network services over large areas, again without requiring electrical wiring .

The foregoing embodiments of the invention have been described and illustrated in conjunction with systems and methods thereof, which are meant to be merely illustrative, and not limiting. Furthermore just as every particular reference may embody particular methods/systems , yet not require such, ultimately such teaching is meant for all expressions notwithstanding the use of particular embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments and features of the present invention are described herein in conjunction with the following drawings:

Fig. 1 is a flowchart of an autonomic drip irrigation device with self sustain hydroelectric power according to some

embodiments of the current invention.

Fig. 2 is a block diagram of an exemplary apparatus for an autonomic drip irrigation device with self sustain hydroelectric power according to some embodiments of the invention.

Fig. 3 is an experimental example for the production of

electricity power in volts, in several water pressure values of 1, 2, 3 and 4 atmospheres using the specific impulse turbine generator combination and a specific nozzle, all which are explicitly shown in the figure.

Fig. 4 is an illustration of an exemplary apparatus for

autonomic drip irrigation device with self sustain hydroelectric power according to some embodiments of the invention.

Fig. 5 illustrates an embodiment using wireless communications to transmit information from measurement units to actuation units, both units using hydroelectric power generation.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention will be understood from the following detailed description of preferred embodiments, which are meant to be descriptive and not limiting. For the sake of brevity, some well-known features, methods, systems, procedures, components, circuits, and so on, are not described in detail.

The current invention is an automatic drip irrigation device capable of performing condition dependent automatic dripping. The irrigation water is used for producing hydroelectric power that is stored or used on the fly, for powering the irrigation device itself or any other electricity consuming device.

In a preferred embodiment, the invention comprises an automatic drip irrigation device. The device is supplied with a pressurized water source, and is capable of irrigating a plant or area from a water line without human or any other intervention. In one

embodiment, the water supply to the drip irrigation device is mediated via a small hollow tube or pipe that is connected from the water source to the device. This element could be made of any material or matter, flexible or rigid.

In one embodiment, the transfer of water from the water source to its destination is determined by opening/closing an electronic valve, mechanical valve, solenoid or the like. The valve state (open/closed) is controlled by an analog or digital controller or microcontroller .

The drip irrigation device is capable of performing condition- dependent drip irrigation. In one embodiment, whether to open the valve for irrigation is determined on sensing the soil moisture using for example a soil moisture sensor. In other embodiments irrigation is determined based on any irrigation determining input parameter or parameters , that are derived from environmental conditions (such as light, temperature, air moisture), timing and weather forecast, external input (for example manual control), and any combinations of these. In another embodiment the condition dependent automatic dripping is determined based on predetermined timing including the consideration of year season, day of week, and time of day, as well as total water input to date.

The automatic drip irrigation device described in the current invention is capable of producing hydroelectric power during each drip irrigation event. In one embodiment, the hydroelectric power is produced by transferring the water from the source pipe via to a micro nozzle, producing a micro water jet stream which is directed to hit and rotate a micro turbine. In another embodiment, the hydroelectric power is produced by transferring the water from the water source pipe to several micro nozzles for producing several micro water jet streams which are directed to hit and rotate one or more micro turbines. The rotation of the micro turbine is transferred e.g. by rigid shaft to a generator for the production of electricity or hydroelectric power. The generator described in the current invention is of AC or DC type. In one

embodiment of the current invention, an impulse turbine is used. In one embodiment of the current invention, a pelton or turgo turbine is used.

The drip irrigation device described in the current invention is capable using and/or storing the electricity or hydroelectric power that it generates, for sustaining the device function or the function of any other electricity consuming element. These electricity consuming elements may be sensors or transmitters, within or outside the device. In one embodiment, the electricity or hydroelectric power generated by the device is stored in a battery or capacitor.

A block diagram of an exemplary apparatus for an automatic drip

irrigation device with s hydroelectric power according to some

embodiments of the invention is shown in figure 2. In this embodiment a valve is located between the main water source and the nozzle and when the valve is in the open state, the narrow water stream flows through the nozzle in the direction of the turbine and hits the turbine.

Consequently, the turbine rotates and the generator turbine assembly transfers electricity to the electricity storage element. In one embodiment, the electricity storage element could be for example a rechargeable battery. After the water stream loses most of its kinetic energy by hitting the turbine bucket it is used for drip irrigation.

Note that a sprinkler that requires the outgoing flow to be of high velocity cannot use all of the kinetic energy of a given flow, since a certain minimum kinetic energy is required on exiting the sprinkler, in order to reach areas to be irrigated. In the case of drip irrigation however, since the outgoing flow need not have any appreciable kinetic energy, an impulse turbine can be exploited to extract nearly all the kinetic energy from the flow, and can also therefore be highly

efficient . An experimental example for the production of electricity in volts at several different water pressure values using a specific impulse turbine generator combination and specific nozzle with an inner diameter of around 0.25 millimeter is shown in Figure 3. Both the water flow and the electricity generated are measured at four different water pressures of 1,2,3 and 4 atmospheres. As one can see from the graph around 1.4 volts are produced for every atmosphere of water pressure.

An illustration of an exemplary apparatus for autonomic drip irrigation device according to some embodiments of the invention is shown in figure 4. The embodiment presented in figure 4 is composed of two main parts. An elongated lower part (403) is expected to be mostly located under ground level. The lower part (403) may contain one or more moisture sensors. In the embodiment presented in figure 4, three moisture sensors (406) are shown, each sensor located in different position along the lower part (403). This multi moisture sensor arrangement, allows the detection of underground moisture levels at more than one depth. The upper part (401) of the embodiment presented in figure 4 contains most of the other elements which are necessary for the appropriate

functionality of the apertures deduced from the current invention, such as turbine, generator, electricity storage etc. The upper part (401) of the embodiment presented in Fig. 4 contains a water inlet (402), a water outlet (405) and a moisture switch (404). The apparatus may contain one or more water inlets or one or more water outlets . According to the embodiment presented in figure 4, the moisture switch (404) controls the required moisture level for operation, namely it controls the threshold level of moisture in the ground below which a dripping event should be activated. In another embodiment, if more than one moisture sensor is located along the lower part (403) the moisture switch (404) controls the decision of which moisture sensor to use, or may use a weighted average of all sensors. In one embodiment the moisture switch (404) is manually controlled by the user. Figure 5 illustrates an embodiment of the invention wherein the control unit 502 with its generator 501 is separate from the sensing unit 504 with its generator 503. In this case the control units may be used less frequently than the sensing units, with the control units at the heads of long hose runs and the sensing units distributed throughout the areas to be irrigated.

A possible embodiment of a hydroelectric drip irrigation unit is shown in Fig. 6. Here the body 601 houses the hydroelectric apparatus. The outflow used for drip irrigation exits through the port 602. Stakes 603 allow the device to be inserted into the soil in a fixed but removable manner

A possible embodiment of a humidity sensor is shown in Fig. 7 in various views. Here the sensor 701 is a some distance from the hydroelectric unit 702, connected thereto by means of an electric line 703.

A possible embodiment of a valve unit is shown in Fig. 8 in various views. The valve has a hydroelectric body 801 as before, that fits snugly over a hose of a certain diameter, and also has valve parts 802 supplied with standard hose connections 802 allowing it to be easily inserted inline with standard irrigation equipment. The valves within the valve parts 802 may be a knife valve, butterfly valve, or any other type of valve suitable for stopping water at e.g. 10 atmospheres, as will be clear to one skilled in the art.

The foregoing description and illustrations of the embodiments of the invention has been presented for the purposes of illustration. It is not intended to be exhaustive or to limit the invention to the above description in any form.

Any term that has been defined above and used in the claims, should be interpreted according to this definition.

The reference numbers in the claims are not a part of the claims, but rather used for facilitating the reading thereof. These reference numbers should not be interpreted as limiting the claims in any form.

Claims

1. A drip irrigation device capable of producing hydroelectric power in a dripping event comprising:

a. an impulse turbine

b. a nozzle adapted to convert a flow of high-pressure, low- velocity water into low-pressure, high-velocity flow and to direct said flow onto said impulse turbine;

c. means for directing an input flow of water into said nozzle; d. an electrical generator in mechanical communication with said turbine ;

e. means for conducting said flow of water out of said turbine; f. means for conducting said flow of dripping water out of the device

wherein electric power is generated in a drip irrigation device, at high efficiency.

2. The device of claim 1 further comprising electrical energy storage means selected from the group consisting of : battery, capacitor; for storing hydroelectric power produced by said generator.

3. The device of claims 1 and 2 wherein said dripping water device is used for irrigation.

4. The device of claim 3 further provided with an electromechanical valve adapted to allow or prevent said input flow of water to said device, or to a second irrigation area, said valve being powered by said generator or battery or capacitor.

5. The device of claim 4 further providing sensing means and control means in electrical communication with said valve, said sensing means adapted to sense the moisture level of an area to be irrigated, and said control means adapted to open or close said valve depending upon said moisture level.

6. The device of claim 5 wherein said nozzle has a fine orifice adapted to direct a jet of water onto the blades of said turbine.

7. The device of claim 6 wherein said sensing means are located on a different irrigation unit than said electromechanical valve, and said electrical communication comprises wireless communication.

8. The device of claim 7 wherein said control means are in wireless communication with multiple sensing units and other wireless

communications sources, and wherein said control means are adapted to use information these multiple sources to control said valve.

9. The device of claim 8 wherein said information is selected from the group consisting of: local moisture level; nearby moisture level;

distant moisture level; weather information; temperature information; predicted future weather information; manual control; and combinations thereof .

10. The device of claim 1 wherein said electrical power is used for loads selected from the group consisting of : lighting; speakers;

movement sensors; humidity sensors; light sensors; pH sensors;

salinity sensors; mineral sensors; cameras; communications means; and combinations thereof.

11. The device of claim 1 wherein the flow out of said turbine atmospheric pressure.