JPH035507A - Dry-proof method and sheet for this use - Google Patents

Abstract

PURPOSE:To prevent water evaporation, and to prevent drying by floating a dry-proof sheet which is a sheet material for which a weatherproof string, a web, or a tape runs orthogonal, and whose entire specific gravity is defined as smaller than one. CONSTITUTION:By sewing a sheet material 2 on front side and a sheet material 3 on back side together with a vinylon string 4 at a certain interval, a dry-proof sheet 1 is formed. In the sheet material 2 on front side, a web in which a polyvinyl alcohol film is partially woven is crossed orthogonal and integrated, the entire body being colored silver with aluminum. In the sheet material 3 on back side, a drawing tape of polypropylene is crossed orthogonal and is integrated, so as to form a hessian cloth. The specific gravity of the sheet 1 for which whole edge circumferences of the sheet materials 2, 3 are sewn together is defined smaller than one, which is floated in the water surface of a reservoir, with both edges anchored on banks. Water evaporation can thus be prevented perfectly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for preventing drought in reservoirs, etc., and a sheet used therefor.

[Conventional technology]

In regions with subtropical climates such as Okinawa, and remote islands with poor water sources, securing water for agricultural and domestic use is an important issue, and traditionally reservoirs have been built to prepare for periods of low rainfall. There is. However, the problem is that the water in reservoirs (hereinafter referred to as "reserved water") evaporates rapidly from the water surface due to solar radiation, reducing the amount of water and eventually running out.

Therefore, recently, a method has been proposed and put into practical use to prevent water evaporation by covering the water surface of a reservoir with a weather-resistant rubber sheet.

[Problem that the invention seeks to solve]

However, since the above-mentioned rubber sheet has a specific gravity higher than 1, it is necessary to attach floats at predetermined intervals and while floating in the reservoir, pull it in all directions to fix the end of the sheet to the shore, which requires extensive work. It was hard labor.

Another problem was that because the entire seat was heavy, it could not be pulled properly without being pulled by a machine.

Furthermore, when the rubber sheet loosens and a recess is formed on the surface side, water and dirt accumulate in the recess between the floats 11, causing rot and dirt, as shown in FIG. 6, which is another problem.

The present invention was made in view of the above circumstances, and aims to provide a drought prevention method that can easily prevent drought by floating a lightweight sheet on the water surface, and a drought prevention sheet used therein.

[Means for solving problems]

In order to achieve the above object, the present invention covers the water surface by floating a sheet having weather resistance and water permeability and a specific gravity of less than 1 on the water surface, and prevents the evaporation of water from the water surface, thereby storing water. A drought-proofing sheet whose primary purpose is a drought prevention method for preventing droughts, and which is a sheet-like body made of weather-resistant threads, webs, or tapes orthogonally crossed, and whose overall specific gravity is set to be less than 1. The second gist is a sheet made by stacking and integrating two or more sheet-like bodies made of weather-resistant threads or tapes crossed at right angles, the sheet-like body constituting the surface layer having a specific gravity of 1. 2-1
．． 4, the specific gravity of the sheet-like body constituting the back layer is set to less than 1, and the overall specific gravity is set to less than 1.

[Effect]

In other words, the present invention breaks the conventional wisdom that drought prevention sheets should be impermeable to prevent water vapor from escaping, and by using a water-permeable lightweight sheet, drought prevention sheets can be easily prevented by simply floating the sheet on the water surface. This is something that can be prevented.

Next, the present invention will be explained in detail based on examples.

〔Example〕

FIG. 1 shows an example of a drought prevention sheet used in the present invention. This drought prevention sheet l has 2 parts as shown in Figure 2.
It has a layered structure, and a sheet-like body 2 on the front side and a sheet-like body 3 on the back side are sewn together at predetermined intervals with vinylon thread (number 10) 4.

The sheet-like body 2 on the front side is made of polyvinyl alcohol (
After the webs of PVA (PVA) films are split orthogonally crossed and integrated, aluminum powder is attached to the surface of the webs, and the whole is colored silver by the aluminum.

On the other hand, the sheet-like body 3 on the back side is made of polypropylene (
It is a so-called Herashan cloth, which is made by integrating stretched tapes of PP) orthogonally.

Note that the entire edge of the sheet 1 made of the two sheet-like bodies 2 and 3 is sewn in a folded state so as not to come apart, and eyelets are formed as necessary.

In the sheet 1, the specific gravity of the sheet-like body 2 on the front side is 1.2.
9, the specific gravity of the sheet-like body 3 on the back side is 0.93, and by adjusting the amount used, the specific gravity of the entire sheet 1 becomes 0.99.
It is set to 2. Therefore, this sheet 1 floats on water.

The sheet 1 described above can be used to prevent water shortage in a reservoir, for example, in the following manner. That is, as shown in FIG. 3, first, a rolled sheet 1 is placed on the bank at one end of the reservoir 10, and one end of the sheet 1 is fixed, and then the sheet 1 is placed on the water surface of the reservoir 10. It opens upward. At this time, the sheet-like body 2 on the front side of the sheet 1 is placed on top.

Then, after completely opening the sheet 1 and placing the sheet 1 so that the center part is floating on the water surface, the other end of the sheet 1 is fixed on the shore at the other end of the reservoir lO (Fig. 4). ).

In this way, since the sheet 1 floats on water, it can be easily stretched on the water surface without requiring the attachment of floats or mechanical traction. Furthermore, it is easy to carry and handle. The sheet-like body 2 on the front side of the sheet 1 is made of PVA, which has excellent weather resistance, so it can be used well for a long period of time.The surface is silver, so it effectively blocks sunlight and lowers the water temperature. It is possible to prevent the generation of steam due to rising. Also, since it blocks sunlight, it can also prevent the growth of algae. Furthermore, conventional drought prevention sheets were torn by the wind or rotted due to rainwater accumulating on the top, but in the above sheet 1, the upper and lower sheet-like bodies 2 and 3 are both tapes perpendicular to each other. It is a thing,
The gaps between the tapes serve as water permeability holes or ventilation holes, so there is no need to worry about them tearing due to wind or collecting rainwater. However, since the entire sheet 1 floats on water, water does not seep out from the gap between the tapes to the surface of the sheet 1, and evaporation of water is almost completely prevented by the covering of the sheet 1.

In addition, in the above embodiment, P is used as the sheet-like body 2 on the front side.
Although a split web of VA film is used, it is not limited to this, but is also made of weather-resistant materials such as vinylon cheesecloth, orthogonal woven fabric or adhesive nonwoven fabric of acrylic fiber tape, orthogonal woven fabric or adhesive nonwoven fabric of acrylic coated polyolefin stretched tape, etc. Any material may be used as long as threads or tapes are perpendicular to each other and water permeable holes are formed. When using one of these materials with a specific gravity greater than 1 (such as PVA), as in the above embodiment, a sheet 1
Make sure that the overall specific gravity is 1 or less. However, it is better that the difference in specific gravity between the two is not too large; generally, the specific gravity of the surface layer should be within the range of 1.2 to 1.4, and the specific gravity of the back layer should be within the range of 0.9 to 0.999. It is preferable to Further, when using one of the above materials with a specific gravity smaller than 1 (polyolefin, etc.), it is sufficient to use one sheet of this material, and there is no need for a multilayer structure.

In this way, the sheet-like body 3 on the back side is used in combination with the sheet-like body 2 on the front side to adjust the specific gravity, and a hydrophobic material is appropriately used as required. Although Heshan cloth is used in the above embodiment, a urethane sponge, polyethylene sponge, etc. with communicating holes may be used instead.

In addition, in the present invention, it is not an essential condition that the sheet-like body 2 on the front side is colored silver with aluminum or the like.
Silver coloring has a higher shading effect against sunlight and can effectively prevent water evaporation.

In addition, since the sheet 1 floats on water, even if the end is not fixed on the shore of the reservoir 10 (see Figure 4), the edge of the sheet 1 itself has a specific gravity greater than 1, as shown in Figure 5. If a material tape or the like is attached, only the edges will be submerged in the water, which has the advantage of being held in place without being torn up by the wind.

Furthermore, in some cases, as shown in FIG. 6, the entire structure may be floated on the water surface of a reservoir, and the end portion may be fixed with a rope 12 or the like.

〔Effect of the invention〕

As described above, since the drought prevention sheet of the present invention floats on water, it does not require installation of a float or mechanical traction, and is easy to handle. In addition, since the sheet material is made of perpendicular tapes, etc., and the gaps between the perpendicular tapes, etc. serve as water permeation holes or ventilation holes, there is no fear of tearing due to wind or accumulation of rainwater. However, since the sheet itself is floating on water, water does not seep out to the surface of the sheet through the orthogonal gaps between the tapes, etc., and water evaporation is almost completely prevented by the sheet covering, preventing water storage from drying out. It can be performed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the drought prevention sheet of the present invention;
Figure 2 is an exploded perspective view of the same, Figures 3 and 4 are explanatory diagrams of its usage, Figure 5 is an explanatory diagram of other usage, and Figure 6 is an explanatory diagram of another usage.
The figure is an explanatory diagram of still another manner of use, and FIG. 7 is an explanatory diagram of a manner of use of a conventional drought prevention sheet. 1... Sheet 2... Sheet-like body on the front side 3...
・Sheet-like body on the back side lO...reservoir

Claims (4)

[Claims] (1) A sheet that is weather resistant and water permeable and has a specific gravity of less than 1 is floated on the water surface to cover the water surface and prevent water from drying out by preventing moisture from evaporating from the water surface. How to prevent drought. (2) A drought-resistant waterproof sheet, which is a sheet-like body made of weather-resistant threads, webs, or tapes orthogonally crossed, and whose overall specific gravity is set to be less than 1. (3) A sheet made by stacking and integrating two or more sheet-like bodies made of weather-resistant threads, webs, or tapes crossed at right angles, where the specific gravity of the sheet-like body constituting the surface layer is 1.
2 to 1.4, the specific gravity of the sheet-like body constituting the back layer is set to less than 1, and the specific gravity of the entire sheet is set to less than 1. (4) The sheet has a two-layer structure, where the front side is a sheet-like body made of orthogonal webs made by splitting polyvinyl alcohol film, and the back side is a sheet-like body made of polyolefin stretched tapes orthogonally crossed. The drought prevention sheet according to claim (3), comprising: