WO2011010930A1

WO2011010930A1 - A water irrigation system

Info

Publication number: WO2011010930A1
Application number: PCT/NL2010/050485
Authority: WO
Inventors: Petrus Mattheus Maria Hoff
Original assignee: P.M.M. Hoff Holding B.V.
Priority date: 2009-07-24
Filing date: 2010-07-26
Publication date: 2011-01-27
Also published as: NL2003277C2

Abstract

The invention relates to a water irrigation system (1) for irrigating water into the soil. The system comprises a container (2) having a wall (4) defining an inner room (30) for containing water (3). Further, the system comprises a capillary cord (6,7) having a capillary end extending outside the container and being arranged to be in fluid communication with water in the container's inner room. The capillary cord comprises a kernel (20) and an enveloping layer (22) surrounding the kernel. The kernel is provided with filaments (21) that are substantially aligned with a longitudinal axis of the cord.

Description

Title: A water irrigation system

The invention relates to a water irrigation system for irrigating water into the soil, comprising a container having a wall defining an inner room for containing water, further comprising a capillary cord having a capillary end extending outside the container and being arranged to be in fluid communication with water in the container's inner room, wherein the capillary cord comprises a kernel and an enveloping layer surrounding the kernel.

Irrigating systems are widely known for providing a dosed water irrigation in subsoil, especially in areas where rainfall is scarce and a relatively humid subsoil is needed, e.g. for growing up vegetation. As an example, a water irrigation system is known that comprises a container wherein rainwater is collected and wherein a pump module pumps the water via pipelines through an area to be irrigated.

However, such a pump driven system needs external energy for proper operation, is subjected to maintenance and/or repairing activities and might be relatively costly.

Further, passive irrigation systems are known using drippers to provide the soil with water. However, a dripper supplies at least

approximately 1 liter of water per day which might be too much for certain applications. It also appears that drippers become blocked due to a flow of calcium or sand entering the dripper's internal passage. It is also noted that dripper's are relatively expensive.

In addition, patent publication AU-B-78307 discloses an irrigating system according to the preamble. The system irrigates indoor plant pots using primary, secondary and tertiary capillary systems. The use of capillary cords that are in fluid communication with water inside the container enables a dosed water transport wherein the use of external energy sources is superfluous. The kernel of the capillary cord is constructed from lengths of sea grass wrapped in a layer of hessian material. However, experiments show that capillary cords in such systems suffer from being blocked after a certain period of time, so that the irrigation function stops.

It is an object of the invention to provide a water irrigation system according to the preamble wherein the irrigation function continues over time without the use of external energy. Thereto, the capillary cord's kernel of the water irrigation system according to the invention is provided with filaments that are substantially aligned with a longitudinal axis of the cord.

By aligning filaments in the kernel with a longitudinal axis of the cord capillary channels are provided that minimize the chance of being blocked by solid particles. From experiments it appears that the water transport function of capillary kernels having longitudinally aligned filaments continues over relatively long time periods, e.g. over months or even years. The capillary transport direction is substantially in said longitudinal direction, through capillary channels created between the filament elements, thereby advantageously providing an effective transport medium for the water.

By providing a hygroscopic kernel, the water transport through the capillary cord is further enhanced.

Further advantageous embodiments according to the invention are described in the following claims.

By way of example only, embodiments of the present invention will now be described with reference to the accompanying figures in which

Fig. 1 shows a schematic perspective view of a water irrigation system according to the invention;

Fig. 2 shows a schematic perspective cross sectional view of a capillary cord comprised by the water irrigation system shown in Fig. 1; and

Fig. 3 shows a schematic perspective view of a container side section of the water irrigation system shown in Fig. 1. It is noted that the figures show merely a preferred embodiment according to the invention. In the figures, the same reference numbers refer to equal or corresponding parts.

Figure 1 shows a schematic perspective view of a water irrigation system 1 according to the invention. The system 1 comprises a container 2 for containing collected rainwater 3. The shown container 2 has a wall including side sections 4a-d and a bottom section 5, thus forming a box- shaped geometry. The wall defines an inner room 30 of the container 2. It is noted, however, that the container 1 may have any geometry that is suitable for containing the rainwater 3. As an example, the container 1 might be cylindrically or tubular shaped. In a practical embodiment, the container 1 might be formed as a tube, a bag or a hose.

It is noted that the container may also contain water that is obtained in another way. As an example, the container can at least partially be filled with fresh water or drinking water. Further, other atmospheric moisture, such as condensed moisture, melted frozen moisture, such as melted hail and/or snow, can be collected in the container.

The shown embodiment of the water irrigation system 1 comprises a container 2 that is open on its upper side, thus allowing rainwater to enter the container 2. In another embodiment, the container 2 comprises an input section for connection to a water filling unit, such as a rainwater collecting unit, a fresh water source, a drainpipe and/or an assembly of drainpipes. The input section may include an inflow aperture for flowing water into the container's inner room 30. Optionally, the container's input section may include a valve for opening and closing the inflow aperture. Then, the container 2 can in principle be formed as a mainly enclosed unit, e.g.

including a top cover section. Further, the container's input section may be provided with a coupling unit for coupling with the water filling unit. As an example, a container implemented as a tube might be connected, via the coupling unit, with a further tube providing the water. Further, the water irrigation system comprises a multiple number of hygroscopic capillary cords 6, 7 extending outside the container 2 and below the soil surface 10. The cords 6, 7 are connected to the container 2 such that they are in fluid communication with water in the inner room 30 of the container 2. Thereto, the wall 4 is provided with a multiple number of corresponding apertures 8, 9. The cords reach through the corresponding apertures 8, 9 into the inner room 30 of the container 2. During use of the system 1, the rain water flows from the inner room 30 into the cords 6, 7 for irrigation outside the container 2. Since the cords have a capillary

characteristic, the water flow rate is relatively low, so that the water may be transported and distributed over a relatively long time interval. In principle, the cords may also extend to the corresponding apertures and abut against associated aperture edges to realize the fluid communication.

The apertures 8, 9 are localized in a wall section 4d or in a bottom section 5 so that the water irrigation process might continue also if the amount of water contained in the container 2 is relatively small.

The structure of the hygroscopic capillary cords 6, 7 is described in more detail referring to Figure 2. Due to the capillary effect, rainwater flows through the capillary cords 6, 7, away from the container 2 towards their ends 6a, 7a extending outside the container 2 and into the subsoil 11, wherein the water leaves the cords 6, 7 and enters the soil 11 so that the collected rainwater is irrigated. It is noted that it is in principle not necessary that the cords extend entirely below the subsoil surface 10. By placing the cord ends 6a, 7a in or just above the soil 11, the collected rainwater may be irrigated towards and into the soil 11.

Since the system according to the invention operates without the use of external energy, an autonomous energy friendly irrigation system is obtained. The system does not require an external energy source and is from an energetic point of view passive. As an additional advantage, using the capillary cord also provides for an autonomous regulating feature, since the amount of capillary water transport is lower when the soil near the capillary end is wet, while on the contrary, when said soil is dry, the capillary water transport increases, thereby obtaining a stable moisture regulating irrigation system.

One of the capillary cords 7 is provided with a branch section 12 so that the rainwater 3 can be distributed at different location in the soil 11, thereby obtaining a more uniform irrigation effect. Obviously, it is also possible to provide cords 7 that have no branches, thus obtaining a simplified and cheaper cord structure.

In an embodiment according to the invention, the diameter of the apertures 8, 9 and the diameter of the corresponding capillary cords 6, 7 have mainly the same size so that the cords fit easy in the apertures.

However, experiments have shown that, though the capillary water transport is satisfactory, a reduced water flow might be obtained in an advantageous way if the aperture diameter is slightly smaller than the corresponding capillary cord diameter. As an example, if the aperture diameter is circa 0.1 mm smaller than the capillary cord diameter, corresponding to a relatively diameter decrease of circa 2% to circa 5%, a surprisingly improved reduction in water flow may be obtained.

Figure 2 shows a schematic perspective cross sectional view of a capillary cord 6 comprised by the water irrigation system 1 shown in Fig. 1. The cord comprises a hygroscopic kernel 20 provided with filaments 21a-c substantially aligned with a longitudinal axis A of the cord 6. Further, the capillary cord 6 comprises an enveloping layer 22 surrounding the kernel 20. By providing the enveloping layer surrounding the kernel, leakage of the water, away from the hygroscopic cord kernel, is counteracted, thereby providing an efficient passive transport medium wherein the water may in principle flow without substantial losses to a desired irrigation area

The aligned filaments 21 form microscopic channels 24 a,b providing the capillary transport in the longitudinal axis A direction of the cord 6. The filaments 21 may include string elements and preferably comprise a natural fiber, such as cotton, linen, jute, silk, hair or wool.

Alternatively or additionally, the filaments may also comprise synthetic fibers such as rock wool or, more preferably a polyamide, more preferably a nylon.

It is noted that also the filaments 21 may transport water. The channels 24 form a volume so that the filaments 21 arranged between the channels may swell and shrink. Filaments 21 can be used that are able to carry and transport water wherein the weight ratio of the water with respect to the filament is more than one, e.g. ten or even a hundred. The water can be transported through a hollow kernel 20 enclosed by an enveloping layer 22.

The enveloping layer 22 may include braided string elements 23. The string elements may comprise synthetic material, e.g. a synthetic polymer, preferably a polyamide, more preferably a nylon, so that a waste away process of the cord that is continuously exposed to soil, is

counteracted. However, also natural, braided material could be used, e.g. for temporal use of the water irrigation system. Preferably, the enveloping layer surrounding the kernel is water impermeable.

In a preferred embodiment according to the invention, a specific nylon type is used, e.g. nylon 6,6 wherein the diamine and the diacid each donate 6 carbons to the polymer chain. Alternatively, other nylon types might be used, e.g. nylon 6, nylon 9, nylon 5,10 made from pentamethylene diamine and sebaic acid, nylon 6,12, nylon 6,11 or nylon 10,12. Molecular chains of nylon fibre are long and straight having no side chains or linkages. By cold drawing, the chains can be aligned and oriented with the lengthwise direction that a highly crystalline structure is obtained, thereby obtaining nearly perfectly aligned filaments in the kernel of the hygroscopic capillary cord. Figure 3 shows a schematic perspective view of a container wall side section 4d of the water irrigation system 1. Here, the side section 4d is provided with a hollow cord guiding element 30 extending outside the plane wherein the side section 4d extends. The aperture 8 through which the cord 6 traverses the side section 4d is formed by the channel inside the cord guiding element 30. Preferably, the guiding element 30 has a longitudinal axis L that is substantially transverse with respect to the plane wherein the side section 4d extends. Further, the guiding element 30 can be

implemented as a hollow tube. The axial length of the hollow cord guiding element 30 can be chosen to be larger than e.g. circa 3 mm, e.g. 8 mm.

However, the axial length of the hollow cord guiding element 30 can also be chosen larger, e.g. 10 mm or more. By providing the hollow cord guiding element 30 the transport of water by the cord improves.

The invention is not restricted to the embodiments described herein. It will be understood that many variants are possible.

The container might be located above or on the soil surface, but might also be buried, at least partially, e.g. to counteract evaporation processes.

Further, the size of the container is in principle not limited, but may be designed depending on specific irrigation requirements such as the size of the area to be irrigated and the duration of the time period that the system is expected to operate without being replenished.

Instead of using a multiple number of capillary cords, the system according to the invention might also be provided with a single capillary cord, e.g. having a multiple number of branches.

The length of the capillary cords is in principle also not limited and might vary between several centimeters to several hundreds of meters.

In a particular embodiment according to the invention, the container is filled with water and than sealed and brought in the

neighborhood of soil wherein a plant or tree that has just been planted, e.g. by burying the container near the root structure of the plant or tree, so that the plant or tree is provided with water in a dosed manner during a certain after-plant irrigation period, e.g. a couple of months. Optionally, the container is refilled after a first irrigation period by removing the seal or opening the valve and flowing water in the container. The container might be formed as a flexible bag or hose, e.g. annular- shaped, at least partially surrounding the plant or tree. The wall of the container might include flexible material, such as a synthetic or natural rubber. Preferably, the wall is made from bio-degradable material. Obviously, a single container can be used to irrigate a multiple number of plants and/or trees.

Other such variants will be obvious for the person skilled in the art and are considered to lie within the scope of the invention as formulated in the following claims.

Claims

CONCLUSIES

1. A water irrigation system for irrigating water into the soil, comprising a container having a wall defining an inner room for containing water, further comprising a capillary cord having a capillary end extending outside the container and being arranged to be in fluid communication with water in the container's inner room, wherein the capillary cord comprises a kernel and an enveloping layer surrounding the kernel, wherein the kernel is provided with filaments that are substantially aligned with a longitudinal axis of the cord.

2. A water irrigation system according to claim 1, wherein the kernel is hygroscopic.

3. A water irrigation system according to claim 1 or 2, wherein the enveloping layer comprises braided string elements.

4. A water irrigation system according to any previous claim, wherein the enveloping layer comprises synthetic material.

5. A water irrigation system according to claim 4, wherein the synthetic material of the enveloping layer includes a synthetic polymer, preferably a polyamide, more preferably a nylon.

6. A water irrigation system according to any previous claim, wherein the filaments comprise a natural fiber, preferably cotton or synthetic material, preferably a polyamide, more preferably a nylon.

7. A water irrigation system according to any previous claim, wherein the aperture diameter and the capillary cord diameter have mainly the same size.

8. A water irrigation system according to any previous claim, wherein the aperture diameter is slightly smaller than the capillary cord diameter.

9. A water irrigation system according to any previous claim, wherein the capillary cord comprises a branch section.

10. A water irrigation system according to any previous claim, wherein the wall is provided with an aperture through which the capillary cord extends.

11. A water irrigation system according to any previous claim, comprising a multiple number of capillary cords being arranged for being in fluid communication, via corresponding apertures in the container wall, with water in the container's inner room.

12. A water irrigation system according to any previous claim, wherein the capillary cord extends below the soil surface.

13. A water irrigation system according to any previous claim, wherein the container comprises an input section for connection to a water filling unit.

14. A water irrigation system according to any previous claim, wherein the container's input section is provided with an inflow aperture for flowing water into the container's inner room, and a valve for opening and closing the inflow aperture.

15. A water irrigation system according to any previous claim, wherein the container's input section is provided with a coupling unit for coupling with the water filling unit.