ES2961413A1 - AUTONOMOUS SOLAR DISTILLER FOR MICRO-IRRIGATION WITH RAINWATER FROM FOREST AND AGRICULTURAL PLANTS (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Autonomous solar still for micro-irrigation with rainwater from forestry and agricultural plants, which includes a tank (1) below ground level and a cover (2) fixed on it, with a concave shape towards the outside and a collection hole (3) rainwater, where the cover (2) includes a minimum level at a distance from its center and a horizontal section (4) between the minimum level and the collection hole (3), and; The tank (1) comprises a containment area (1.1) and a spillway opening (5) towards the ground capable of allowing the contained water to overflow, where said spillway opening (5) is located in correspondence with the minimum level of the cover (2) such that it is also capable of allowing condensed water to escape. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Autonomous solar distiller for micro-irrigation with rainwater of forestry and agricultural plants

Technical field of the invention

The present invention corresponds to the technical field of agriculture and forestry plantation, specifically to an autonomous solar still that allows micro-irrigation using rainwater from these plantations.

Background of the Invention

Currently, the growing problems due to climate change and increasing levels of water stress due to lack of water in all regions of the world are well known. This is why it is necessary to emphasize the urgent need to create resilient water management systems, so that every drop of water counts.

The Food and Agriculture Organization of the United Nations (FAO) and the International Commission on Irrigation and Drainage (ICID) have adopted the terms "Localized irrigation" or "microirrigation" to define irrigation systems that allow optimal use of water. . In these systems, small amounts of water infiltrate directly to the roots of the plants, increasing productivity and irrigation yield per unit area.

In the agricultural sector, the existence of these micro-irrigations is recommended, especially in arid and/or remote areas, far from urban centers, where there are limitations to the availability of water in quality and quantity necessary throughout the production cycle.

In the forestry sector, the need for these micro-irrigations is evidenced by the limited success that forest repopulation usually has under traditional methods. The planting of forest species, as well as the establishment of seedlings in forest repopulation, is one of the critical points of the restoration/repopulation process in Mediterranean conditions and in general in all regions of the world with marked water stress. To help in this process, different devices and systems have been developed in recent years that have been used operationally in forest restoration programs, such as protective tubes, hydrogels, organic amendments, microbasins, etc., in order to help the plant to develop a more functional root system in the period from planting until the appearance of summer water stress.

Providing supportive irrigation in the first years of reforestation greatly increases the survival capacity of the plants. But this support irrigation is not always viable, either due to the difficulty of access due to the nature of the land where the action is carried out, or due to the impossibility of supporting the costs involved in transporting water for irrigation, since We are talking about repopulation on large surfaces, with complex access in most cases, and these are not acceptable actions on a forest scale.

In this sense, several types of devices have currently been developed whose objective is the irrigation of plants in these cases, and as an example of the state of the art the reference documents WO2015063243, ES2304905, ES2351840, EP3885017A1, DE2626902A1, can be mentioned. and DE102004053728A1.

Reference document WO2015063243 defines a seedling planting apparatus, which includes a tank and a lid, the tank being below ground level. This tank includes a container filled with water and irrigation means to provide a controlled flow of water from the container, formed by capillary wicks that allow the supply of water to the lower area of the land.

This capillary wick irrigation system, with practice, has shown to present certain drawbacks since it requires maintenance that is not usually possible in the conditions in which these plantations are developed. Thus, the capillary wick that is used to direct the water contained in the tank towards the bottom of the soil where the roots of the plant are located, becomes clogged over time and must be replaced with a new one, which It involves uninstalling the buried device, in order to replace the wick that is usually connected to the bottom of the tank.

Furthermore, for this system to work, it is indicated that it is necessary to carry out a first artificial filling in order to guarantee the initial functionality of the wick. Thus, although it will later be filled with rainwater, this first filling is required by operators, which requires time, labor and means to carry the water to the repopulation sites, which may not be easily accessible.

These drawbacks are of relevant importance, because when the reforestation of a forest or a plantation in a large area or difficult to access land is being treated, these problems cannot arise, since maintenance and/or initial filling of the devices with water it turns out to be unviable. This generates a big problem of effectiveness in this type of devices.

The reference document ES2304905 exposes a device formed by a terracotta container with an upper filling mouth, and some holes below the level of said filling mouth.

Threads of synthetic fibers emerge from said holes, which have at least one inner section with an end extended inside the container up to a weight at its bottom, and an outer section arranged on the outer surface of the container in a knotted or intertwined manner, in contact with the earth, suitable so that once the container is buried up to the level of the upper mouth, the threads carry out a gradual transfer of water between the interior and exterior of the container by capillarity.

This device bases its operation on capillarity through threads of synthetic fibers, in a similar way to the first mentioned document, which worked through a capillary wick and presents the same drawbacks in terms of clogging of the threads and need for maintenance, in addition to not Capture rainwater for filling.

The reference document ES2351840 determines a rain collection tank for irrigation with a protective effect of the nurse plant type, which comprises a tank to collect and store rainwater, which incorporates a device for delayed discharge of water to a plant, and a protection structure of the plant against external agents, formed by a reticulated cylindrical protector with shading mesh.

This document relates different delayed discharge mechanisms to provide irrigation water to the plant, including valves, microtubes, fibers and clay. In practice, for these devices the only viable mechanisms for irrigation, of those exposed in the document, would be the fibers or wicks and the clay, where the most common is the use of ceramic cones, since the valves and microtubes, the which are not observed in practice, should not operate for more than several days, since they require pressure to function and these systems do not provide it, and would have problems with air entry inside them, requiring purging for their operation. Clays or ceramic cones present the same problem as wicks, the loss of capillarity over time and must be replaced periodically, which again is a great inconvenience when we talk about forestry-type repopulation or crops in remote areas.

In addition to these problems, this device, like the first mentioned, needs to be artificially filled in its installation phase for its operation.

The devices in the documents seen so far mainly present two problems. The first of them, which use water outlet systems to the plant that become clogged over time, ceasing to be functional if a periodic review is not carried out, which makes their use more expensive and difficult to use, while the second problem is that there is currently no such device that can be installed next to the plant without water, waiting for it to fill naturally with rainwater, which would also make its use considerably cheaper and easier.

All these problems have generated a search for more effective irrigation systems, understanding that the most suitable method to solve the first problem is to use devices based on solar distillation, which is an irrigation technique that allows optimal use of water using energy. of the sun as a driving element of the distillation process and movement of water. These devices have a tank with water and a transparent cover so that water is provided to the plant through condensation, increasing its performance in the summer period. In them there is no mechanism for water output to the plant, only the dripping of condensed water which is what irrigates the plant.

These irrigation systems are activated to a greater extent on days with the highest heat and lowest relative humidity, which are precisely those in which the plant is subjected to greater water stress. A solar distillation micro-irrigation system can solve the problems presented by capillary irrigation systems (wicks, ropes or ceramic pieces), which by their very nature have a finite duration on the ground, and must be replaced periodically, which means a great drawback when we talk about forestry-type repopulation or crops in remote areas.

An example of this is the case of reference document EP3885017A1, which defines a device that produces distilled water with solar radiation from contaminated water.

This distiller has a first container, to contain contaminated water, an outer cover, a water collection unit and an inner cover to enclose a volume in the first container. The inner and outer covers are designed to transport condensed water to the water collection unit, the outer cover being transparent to heat the water contaminated in the first container by solar radiation, although it may also be provided with electrical heating means, or both. .

This device does not solve the second problem stated, since it is not an autonomous device, since it is necessary to provide a volume of contaminated water with which to start the distillation process. This provides an additional complication in the case of reforestation and large areas.

Reference document DE2626902A1 defines a large-surface, non-freshwater solar distillation system using a gas-tight cover, formed by a pneumatically stabilized transparent plastic cover. The system serves as a greenhouse for growing plants, for which non-fresh water is circulated over an optical filter and condensed and collected in a fresh water tank.

This system does not direct irrigation water directly to the plants, but rather serves to distill salt water, obtaining a volume of fresh water. The additional problem is that for this it is not possible to use rainwater, but rather it is necessary to provide the volumes of salt water that you want to distill. It therefore requires continuous maintenance to restore the volumes as the water evaporates.

In the case of the reference document DE102004053728A1, it also refers to a solar still for salt water or contaminated water, which implies the need to initially and from time to time provide a volume of said water to be distilled, in order to obtain a corresponding volume of fresh water for irrigation.

All of these solar stills have the problem that they are not autonomous, since manual filling is necessary to allow them to function and they are not rainwater collectors. Furthermore, to fill with water it is necessary to manipulate the device, opening the cover, thus allowing access to the area of the water tank necessary for distillation. This greatly complicates the process.

Therefore, there is currently a serious problem in the field of agriculture and forestry plantations to which it is necessary to find a solution, since the devices available to provide micro-irrigation to plants all present a series of drawbacks that, either they imply the need for maintenance work and initial actions on them, which complicate the use of these devices in large and/or inaccessible areas, or they require a continuous supply of salty or contaminated water that allows having a volume of water sweet from the condensation of the previous one. In this way, none of them can be considered an autonomous device that allows effective micro-irrigation in large or difficult-to-access areas and all of them entail a high manufacturing cost, making their use on a large scale more difficult.

Description of the invention

The autonomous solar still for micro-irrigation with rainwater from forestry and agricultural plants presented here includes a water collection and containment tank located buried below ground level and a cover fixed over the tank at a level higher than the of the land, being arranged on or at ground level, which has a concave shape towards the outside and a hole for collecting rainwater.

In this solar still, the cover comprises a minimum level located at a distance from the center of it and a horizontal connection section between the minimum level and the collection hole, so that said collection hole is located at that same distance. minimum level.

Furthermore, in this solar still, the tank includes a water containment area from the base of the tank to a maximum level lower than the minimum level of the roof, and a spillway opening towards the ground located at said maximum level capable of allowing the overflow of the contained water, where said spillway opening is located in correspondence with the minimum level of the roof such that it is capable of also allowing the exit of the condensed water on the roof.

With the autonomous solar still for micro-irrigation with rainwater of forestry and agricultural plants proposed here, a significant improvement in the state of the art is obtained.

This is because a completely autonomous device is achieved, whose filling, once installed, is carried out naturally with rainwater, so its installation is simple and quick, requiring no prior action or any initial filling or purging. The installation is only carried out with the tank buried close to a seedling, or with the seedling located concentrically with the device, and such that the cover is located at or above ground level, so that, with the first rains, the device It begins to fill with water and begins to operate.

In addition, it presents a design that allows mass manufacturing and stacking of the pieces, making them stable in their placement and use.

With this device it is possible to direct the water produced right to the root of the plant to which the irrigation is provided, making this irrigation very effective and beneficial for it.

Likewise, this device presents two irrigation options directed towards the root of the plant.

The first of them is the already mentioned condensation, since the water condensed on the lower surface of the roof is all directed towards the minimum level of the roof, so that when it falls it does so through the spillway opening, right where it falls. Find the root of the plant in the ground.

On the other hand, the second irrigation option occurs in the case in which, in times of heavy rain, an amount of water is collected that exceeds the containment volume of the tank of this device, since all the excess water comes out through this same opening. spillway and also water the roots of the plant directly.

With this, the availability of water supply to the plant is increased beyond that obtained by distillation.

It is a completely autonomous device as it works without the need for any type of maintenance, since there are no elements that lose effectiveness, nor is it necessary to add any water at any time. However, it allows an additional mode of use, if desired, in which manual filling of the tank with salt water or contaminated water is possible, in which case the device continues to function effectively, without the need for manipulation or maintenance.

Furthermore, this device can work in two modalities, a first in which it is placed buried adjacent to the plant to be watered and a second option in which it is placed buried with the plant in the central area of it, so that the Irrigation water reaches not only one side of the plant but also the entire area around it.

It is therefore a completely effective solar still in the objective set here, as it manages to combine the capacity for autonomy when supplied by rainwater, the durability of the system's operation, in terms of the irrigation motor, which is solar energy, and at the same time it allows water to be placed close to the plant at the time it needs it most, being a simple and easy-to-produce system that can represent a low cost for large-scale application in forest repopulation or agricultural plantations.

This solar still makes it possible to complete the production cycle of agricultural plants and, in the case of perennial or forest plants, ensure a sufficiently developed root system so that it is able to survive on its own. At this time, once its function of supporting the development of plants in their first years of life has been fulfilled, the device is completely reusable and can be moved to another location for a new use.

Brief description of the drawings

In order to help a better understanding of the characteristics of the invention, in accordance with a preferred example of its practical implementation, a series of drawings are provided as an integral part of said description where, with an illustrative and non-limiting nature, it has been represented the following:

Figure 1.- Shows a perspective view of the cover of a solar still, for a first preferred embodiment of the invention.

Figures 2.1, 2.2 and 2.3.- Show plan, elevation and profile views with a view of detail A, of the cover of a solar still, for a first preferred embodiment of the invention.

Figure 3.- Shows a perspective view of the tank of a solar still with a view of detail B, for a first preferred embodiment of the invention.

Figures 4.1, 4.2 and 4.3.- Show plan, elevation and profile views of the tank of a solar still, for a first preferred embodiment of the invention.

Figure 5.- Shows a perspective view of a solar still, for a first preferred embodiment of the invention.

Figures 6.1, 6.2 and 6.3.- Show plan, elevation and profile views of a solar still, for a first preferred embodiment of the invention.

Figure 7.- Shows a schematic view of the operation of a solar still, for a first preferred embodiment of the invention.

Figure 8.- Shows a perspective view of the cover of a solar still, for a second preferred embodiment of the invention.

Figures 9.1, 9.2 and 9.3.- Show plan, elevation and profile views of the cover of a solar still, for a second preferred embodiment of the invention.

Figure 10.- Shows a perspective view of the tank of a solar still with a view of detail C, for a second preferred embodiment of the invention.

Figures 11.1, 11.2 and 11.3.- Show plan, elevation and profile views of the tank of a solar still, for a second preferred embodiment of the invention.

Figure 12.- Shows a perspective view of a solar still, for a second preferred embodiment of the invention.

Figures 13.1, 13.2 and 13.3.- Show plan, elevation and profile views of a solar still, for a second preferred embodiment of the invention.

Figure 14.- Shows a schematic view of the operation of a solar still, for a second preferred embodiment of the invention.

Detailed description of a preferred embodiment of the invention

In view of the figures provided, it can be seen how in a first preferred embodiment of the invention, the autonomous solar still for micro-irrigation with rainwater of forest and agricultural plants proposed here, comprises a collection tank (1). and water containment located buried below ground level and a cover (2) fixed on the tank (1) at a level higher than that of the ground, which has a concave shape towards the outside and a collection hole (3) of rain water.

The cover (2) of this solar still comprises a minimum level located at a distance from the center of it and a horizontal section (4) connecting the minimum level and the collection hole (3), as shown in Figures 1, 2.1, 2.3, 5, 6.1 to 6.3 and 7, so that said collection hole (3) is located at that same minimum level.

On the other hand, the tank (1) includes a containment area (1.1) of water from the base of the tank (1) to a maximum level lower than the minimum level of the cover (2), and a spillway opening (5 ) towards the land located at said maximum level capable of allowing the overflow of the contained water, where said spillway opening (5) is located in correspondence with the minimum level of the cover (2) such that it is capable of allowing the exit of the water condensed on the cover (2).

In a first preferred embodiment of the invention, the cover (2) has the shape of an oblique cone or pyramid, and its minimum dimension is formed by an eccentric vertex (6), as can be seen in Figures 2.2, 2.3, 6.1,6.3 and 7.

Furthermore, in this first embodiment, as shown in Figure 2.3, the distiller comprises an apex-shaped piece (7) for collecting condensation, fixed at the vertex (6) of the cover. In this way, the fall of condensed water is directed more precisely to the desired location.

On the other hand, in this first preferred embodiment, the tank (1) comprises a tubular channel (17) that emerges from the base of the tank (1) and is located closer to the outer contour of said base, as shown. represented in Figures 3, 4.2, 4.3, 5, 6.2, 6.3 and 7. Said tubular channel (17) forms the spillway opening (5) of the tank (1).

In other embodiments, the distiller may also comprise an extension of the tubular channel (17) from the base of the tank (1) towards the ground. In this way, a greater depth of irrigation would be achieved that could be necessary for certain types of plants.

Furthermore, in this first embodiment, the tank (1) has a section whose dimension increases with height while the tubular channel (17) that emerges from its base presents a section whose dimension decreases with height. In this specific case, both the tank (1) and the tubular channel (17) have a truncated cone shape, although in other embodiments they may have a different shape, such as truncated pyramidal.

This condition of increasing section in the case of the tank and decreasing with height in the case of the tubular channel allows the stacking of said tanks (1) of the distillers, for better and simpler transportation and storage.

The spillway opening (5), as shown in Figures 5, 6.1 to 6.3 and 7, is aligned with the drop zone of the cover (2), that is, with the vertex (6) that materializes the minimum level of the cover (2) in this first embodiment, so that the output of said condensed drops goes directly to the ground and thus performs micro-irrigation to the plant. This tubular channel (17) that forms the spillway opening (5) is located as close as possible to the contour of the tank (1), so that it is also located as close to the plant, to thus increase the performance of the operation.

In this first preferred embodiment of the invention, the cover (2) is joined by its outer contour to the outer contour of the tank (1) by means of hermetic connection means. To facilitate assembly, both the cover and the tank have a mark that indicates how both should be joined so that the vertex (6) of the cover and the spillway opening (5) are aligned.

By being joined in this way, a microclimate is generated inside the distiller with an increase in temperature due to the action of solar radiation, causing the evaporation of the water stored in the tank (1), which subsequently condenses on the inside of the distiller. cover (2), forming drops that when they acquire the necessary size and weight and by the action of gravity, are directed to the minimum level of the cover (2), formed by a vertex (6) from where they will be released.

As shown in Figures 1, 2.2, 2.3, 5, 6.2, 6.3 and 7, in this first preferred embodiment, the cover (2) comprises a rainwater inlet conduit (8) with a first end ( 8.1) connected to the collection hole (3) and a second end (8.2) located above the containment area (1.1) of the tank (1) and whose length is equal to or less than the distance between said collection hole (3). and the base of the tank (1). In this way, placing said second end (8.2) very close to the base of the tank (1) prevents the entry of outside air into the tank, favoring the distillation process inside the distiller.

This water inlet conduit (8) for filling the tank (1) is offset with respect to the spillway opening (5), which in this first embodiment is formed by the tubular channel (17) that emerges from the base. of the tank (1), in this way the water collected by the upper part of the cover (2) is prevented from coming out directly through the spillway opening (5) towards the ground, as represented in Figures 5, 6.1 to 6.3 and 7.

In this first preferred embodiment, the inlet conduit (8) is connected to the collection orifice (3) by means of removable connection means. In this way, it is possible to disconnect it for easier storage and transportation of the distiller elements.

In other embodiments, such as in a second mode that will be seen later, it may occur that the inlet conduit (8) is connected to the collection orifice (3) by means of an integral joint.

In this first preferred embodiment of the invention, the tank comprises anchoring means to the ground, as shown in Figures 3, and 4.1 to 4.3.

These anchoring means are formed by pegs that are inserted through the entrance hole of some of the slots (9) existing at the base of the tank (1) to prevent its overturning in the event of adverse weather conditions in the area, especially strong winds. .

The cover (2) of this solar still is made of transparent or translucent material, so that it allows the solar rays to pass through, evaporating the water inside the tank (1). The case of a translucent cover (2) can be very interesting for those cases in which the temperatures are excessively high, so that with the translucent cover the performance can be reduced to avoid too rapid condensation of the water in the tank.

Thus, once the solar still is installed, with the first rains the filling of the tank (1) begins, and if its volume is exceeded, it will begin to be relieved through the spillway opening (5), watering the roots directly. The water that is contained in it is subjected to the distillation process, so that the drops condensed on the lower surface of the cover (2) flow to the vertex (6) of the same and the existing apex (7). at this vertex (6) favors the fall of the drops at that point. All the drops accumulated on the cover (2) are directed to that apex (7) except those that in their direction touch the horizontal section (4) connecting the vertex (6) with the collection hole (3), which return to fall into the tank (1).

In a second preferred embodiment of the invention, as can be seen in Figures 8 and 9.1 to 9.3, the cover (2) has a central opening (10) capable of allowing the passage of a plant and the minimum height in this case, it is located along a ring (11) concentric with said central opening (10) and closer to the central opening (10) than to the outer contour of the cover (2).

In this case, as shown in Figures 10 and 11.1 to 11.3, the tank (1) comprises a tubular channel (17) concentric with the tank (1), which forms the spillway opening (5). This tubular channel (17) emerges from the bottom of the tank (1) at a distance from the outer contour of the tank (1) such that the ring (11) with the minimum height of the cover (2) is arranged in correspondence with the interior space a said spillway opening (5).

As shown in Figures 13.2 and 13.3, in this second preferred embodiment of the invention, the distiller also comprises a rainwater inlet conduit (8) with a first end (8.1) connected to the collection hole ( 3) and a second end (8.2) located above the containment area (1.1) of the tank (1) and whose length is equal to or less than the distance between said collection hole (3) and the base of the tank (1).

In this second embodiment, this inlet conduit (8) is connected to the collection hole (3) by means of an integral joint. Furthermore, in this case, said inlet duct (8) has a decreasing section from the first end (8.1) to the second end (8.2), to favor the stacking of the covers of different distillers, for the transport and storage of the themselves.

As shown in Figures 10, 11.2, 11.3 and 12, in this second preferred embodiment the tank also has a section that increases with height, specifically in a truncated conical shape, while the tubular channel (17), in this case Concentric, it has a section that decreases with height and is also truncated-conical in shape, which also allows for convenient transportation and storage of the tanks.

In this second preferred embodiment of the invention, the tank (1) and the cover (2) also have first hermetic joining means of the outer contour of both and second means of joining the central opening (10) of the cover (2) with a circular piece (12) of the tank (1) connected to the spillway opening (5). In this case, the connection of the circular piece (12) with the spillway opening (5) is formed by radial connection elements (13) that divide the spillway opening (5) of the tank (1) into sections (14). ), as can be seen in Figures 10 and 11.1.

In other preferred embodiments, said second connecting means are formed by a connection grid on the spillway opening (5).

In this second preferred embodiment, the circular piece (12) of the tank (1) has a central channel (15) to protect the plant, which emerges from it towards the upper part of the cover (2), as shown. as shown in Figures 12, 13.2, 13.3 and 14. This central channel (15) protects the plant inside from the possible presence of rodents in the planting area.

Specifically in this case, said central protection channel (15) includes holes (16) for aeration of the plant on its lateral surface.

In this second embodiment, as in the first proposed mode, once the device is placed on the ground with the plant, the installation is completed. When it starts to rain, the cover (2), having a concave shape like a funnel, directs the water towards the minimum level, which in this case is a centered circular ring (11) and from it, as it is connected to the drainage hole. collected (3), runs towards the interior of the tank (1).

The tank (1) stores rainwater from the roof (2) in the containment area (1.1). When it is full, all the rainwater that the cover (2) continues to collect overflows through the spillway opening (5), through its sections (14), providing more water supply to the plant in addition to that generated by distillation. solar.

The micro-irrigation process occurs in this case since the drops accumulated on the inside of the cover (2) fall to the ring (11) of the cover (2) that forms the minimum level, from where they are released, entering through the sections (14) of the spillway opening (5) of the tank (1), to fall into the ground around the plant.

In other preferred embodiments of the invention, the cover (2) comprises folds and/or undulations capable of increasing the effective condensation surface of the evaporated water from the tank.

Likewise, in other embodiments the distiller comprises water absorption means in the contact area of the water droplets with the ground, formed by a geotextile material and/or a hydrogel.

This distiller is preferably made using biodegradable and/or reusable materials, with the aim of being environmentally friendly.

The embodiments described constitute only examples of the present invention, therefore, the specific details, terms and phrases used herein are not to be considered as limiting, but are to be understood only as a basis for the claims and as a representative base that provides an understandable description as well as sufficient information to the person skilled in the art to apply the present invention.

Claims (1)

1- Autonomous solar distiller for micro-irrigation with rainwater from forestry and agricultural plants, which includes a tank (1) for collecting and containing water located buried below ground level and a cover (2) fixed on the tank (1) at a level higher than that of the ground, which has a concave shape towards the outside and a collection hole (3) for rainwater, characterized in that - the cover (2) comprises a minimum dimension located at a distance from the center thereof and a horizontal section (4) connecting the minimum dimension and the collection hole (3), so that said collection hole (3) is located at that same minimum level, and; - the tank (1) includes a water containment area (1.1) from the base of the tank to a maximum level lower than the minimum level of the cover (2), and a spillway opening (5) towards the ground located in said maximum level capable of allowing the overflow of the contained water, where said spillway opening (5) is located in correspondence with the minimum level of the cover (2) such that it is also capable of allowing the exit of condensed water therein . 2- Distiller, according to claim 1, where the cover (2) has the shape of an oblique cone or pyramid, and its minimum height is formed by an eccentric vertex (6). 3- Distiller, according to claim 2, comprising an apex-shaped piece (7) for collecting condensation, fixed to the vertex (6) of the cover (2). 4- Distiller, according to any of the previous claims, where the tank comprises a tubular channel (17) that emerges from the base of the tank (1) and is closer to the outer contour of said base, where said tubular channel (17) forms the spillway opening (5). 5- Distiller, according to claim 4, which comprises an extension of the tubular channel (17) from the base of the tank (1) towards the ground. 6- Distiller, according to any of the previous claims, where the cover (2) is joined by its outer contour to the outer contour of the tank (1) by means of hermetic connection means. 7- Distiller, according to claim 1, where the cover (2) has a central opening (10) capable of allowing the passage of a plant and the minimum level is located along a ring (11) concentric with said central opening. (10) and closer to the central opening (10) than to the outer contour of the cover (2). 8- Distiller, according to claim 7, wherein the tank (1) comprises a tubular channel (17) concentric with the tank (1), which forms the spillway opening (5) and emerges from the bottom thereof at a distance from the contour. exterior such that the ring (11) with the minimum dimension of the cover (2) is arranged in correspondence with the interior space of said spillway opening (5). 9- Distiller, according to any of claims 7 or 8, wherein the tank (1) and the cover (2) have first hermetic joining means of the outer contour of both and second means of joining the central opening (10). of the cover (2) with a circular piece (12) of the tank (1) connected to the spillway opening (5) thereof. 10- Distiller, according to claim 9, where the second connecting means are formed by radial connection elements (13) that divide the spillway opening (5) of the tank (1) into sections (14). 11- Distiller, according to claim 9, wherein the second connecting means are formed by a connecting grid on the spillway opening (5). 12- Distiller, according to any of claims 7 to 11, where the circular piece (12) has a central channel (15) to protect the plant that emerges from it towards the upper part of the cover (2). 13- Distiller, according to claim 12, where the central protection channel (15) comprises holes (16) for aeration of the plant on its lateral surface. 14- Distiller, according to any of the previous claims, where the tank (1) has a section that increases with height. 15- Distiller, according to any of claims 4, 5 or 8, wherein the tubular channel (17) has a section that decreases with height. 16- Distiller, according to any of the preceding claims, comprising a rainwater inlet conduit (8) with a first end (8.1) connected to the collection hole (3) and a second end (8.2) located on the containment area (1.1) of the tank (1) and whose length is equal to or less than the distance between said collection hole (3) and the base of the tank (1). 17- Distiller, according to claim 16, where the inlet conduit (8) is connected to the collection orifice (3) by means of removable connection means. 18- Distiller, according to claim 16, where the inlet conduit (8) is connected to the collection orifice (3) by means of an integral joint. 19- Distiller, according to claim 18, where the inlet duct (8) has a decreasing section from the first end (8.1) to the second end (8.2). 20- Distiller, according to any of the previous claims, where the cover (2) is formed by a transparent or translucent material. 21- Distiller, according to any of the previous claims, where the tank (1) comprises anchoring means to the ground. 22- Distiller, according to any of the previous claims, where the cover (2) comprises folds and/or undulations capable of increasing the effective condensation surface of the evaporated water from the tank. 23- Distiller, according to any of the previous claims, which comprises water absorption means in the contact area of the water droplets with the ground, formed by a geotextile material and/or a hydrogel.