JPH07229171A - Method for recovering water, and device therefor - Google Patents

Abstract

PURPOSE:To effectively purify water at a low cost by supplying recovered raw water to a storage tank, burying a porous pipe in a medium layer for dipping the evaporated raw water to pass the water under a negative pressure, and recovering the penetrated evaporated raw water through the porous pipe. CONSTITUTION:A raw water storage tank 1 is provided in a housing 2, a medium layer 3 is arranged under it, and porous pipes 4 are connected in series to each other by tubes 5. Raw water is supplied to the raw water storage tank 1, and the evaporated raw water is dipped in the medium layer 3, passed through the porous pipes 4 in the medium layer 3, and recovered. As the medium layer 3, a material in which water is easy to permeate, steam is easy to diffuse, and movement of water is easy to cause by capillary condensation or capillarity is particularly preferred. As the material of the porous pipes 4, a hydrophilic material or a material subjected to hydrophilic treatment is preferably used, and a cylinder having a pore diameter of about 10mum formed by molding and baking a pottery clay rich in quartz is particularly preferred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for collecting water and a device therefor.

[0002]

2. Description of the Related Art Obtaining good quality water at low cost in arid areas and remote islands is a demand not only from the standpoint of living convenience but also from the viewpoint of population growth measures and global environmental conservation. A great deal of effort and efforts have been made to own and efficiently use this water. In general, river water flowing through arid areas has a high salt concentration and is often unsuitable for domestic and irrigation water.

As described above, as a method for treating river water or ground water having a high salt concentration and not suitable for direct use as irrigation water, or polluted water requiring purification treatment,
A method of evaporating and collecting water is effective. For example, a solar water purifier is a flat building with a transparent resin plate, glass, film, etc. as a roof, in which a sheet or plate for storing the raw water to be evaporated is placed, and it is heated by solar heat to generate water vapor and Water is condensed by condensing water vapor into a portion corresponding to a transparent roof due to the temperature difference of the outside air, and the condensed water flowing from the roof having a slight inclination is collected.

[0004]

However, such a solar water purifier does not have a large amount of water acquired per unit area / unit time, and when a relatively large amount of water is to be acquired, a multistage water purifier is required. The cost tends to be higher than that of the method using a flash distillation method or a method using a reverse osmosis membrane, and it has been considered that improvement of performance is a prior issue for efficiently obtaining fresh water. Therefore, until now, it has been considered to be a method of obtaining fresh water on a relatively small scale in uninhabited islands and remote areas where it is difficult to use electric power.

Therefore, as a result of various investigations, the present inventors have conducted various studies to find out a method capable of increasing the amount of water obtained at a relatively low cost, and as a result, the water vapor evaporated from raw water is transferred to the medium layer. Surprisingly, by circulating water in a porous tube that is installed in the medium layer and is always adjusted to a negative pressure, and recovering the evaporated raw water in the medium layer through a negative pressure transfer through the porous tube. The inventors have found that the amount of water to be acquired has dramatically improved, and have completed the present invention.

[0006]

That is, the gist of the present invention is to supply raw water to be recovered to a raw water storage tank, to allow evaporated raw water to penetrate into a medium layer, and to embed a porous pipe in the medium layer. Then, water is circulated in the porous tube under negative pressure, and the evaporated raw water that has penetrated into the medium layer is recovered by passing through the porous tube, and the raw water to be recovered. For storing the raw water, a medium layer for infiltrating the evaporated raw water, a porous pipe buried in the medium layer for collecting the evaporated raw water by passing through it, and the porous pipe for supplying water under negative pressure to the porous pipe. A water recovery device comprising a water storage tank provided upstream of a quality pipe and a water reception tank for receiving water flowing through the porous pipe.

The present invention will be described in detail below. First, in the present invention, the raw water to be recovered is stored in the raw water storage tank. The raw water is not particularly limited, and examples thereof include seawater, river water, water with high salt concentration such as groundwater, and polluted water.

The shape and material of the raw water storage tank are not particularly limited, but it is desirable to promote evaporation of moisture by using a type having a shallow water depth and a large surface area (for example, a shallow dish type) so that evaporation can easily occur. Simply excavate the ground shallowly and place a non-permeable sheet such as a plastic sheet on it.
This can also be used as a raw water storage tank. Furthermore, it is preferable to surround the raw water storage tank with a panel or a film so that the environment is as tightly sealed as possible, and to keep the evaporated water vapor from being dissipated.

The medium tank into which the evaporated raw water penetrates is usually installed near the raw water storage tank. As a material for the medium layer, a substance is particularly preferable, which is a substance in which water easily permeates, water vapor easily diffuses, and water easily migrates due to capillary condensation or capillarity. Since the heat of condensation of water vapor is absorbed by this medium layer, a substance having a large heat capacity and good thermal conductivity is preferable. As such materials, materials that make up the earth such as desert soil and sand can be used as they are, but diatomaceous earth, silica sand,
Acid clay, silica, alumina, shirasu balloon, fired porous material, charcoal and the like can also be suitably used. Also,
It does not necessarily have to have an affinity for water, and gravel, glass spheres, chaff charcoal, perlite, vermiculite, fine-grained plastics, and the like can be used. In addition, water-absorbent polymers with water retention, sponge-like moldings, non-woven fabrics,
Various fibers, mats, sponges, etc. can also be used as materials for covering porous tubes such as ceramic tubes. However, viscous soils are not preferable because viscous substances hinder the passage of water vapor and water. Naturally, substances that are easily soluble in water are not preferable.

When the obtained water is used as drinking water, it is convenient to use a clean medium material. In the present invention, the porous tube is embedded in the medium layer. There is no particular restriction on the depth to be buried, but it is usually 1
It is preferably about 100 cm. If it is too shallow, it is easily affected by the temperature of the surface of the earth, which is disadvantageous for the condensation of water vapor.
If it is too deep, a large negative pressure difference must be taken in order to reach the steam.

As a material for the porous tube, ceramics, concrete, glass and the like are generally preferable, but a porous molded body made of a sintered metal, polyethylene, polypropylene, rubber or other plastics as a raw material, A cylindrical material made of a material that can be used as a filter material can be used. A hydrophilic material or a hydrophilized material is preferable from the viewpoint of collecting water vapor and water. It is desirable that these porous materials have pores having a pore diameter in the range of about 0.01 to 200 μm. If they are smaller than this, clogging easily occurs during use and fluid flow resistance is large, so that water productivity is high. If it is bad, or if it is rougher than this, air will flow in, and it will be difficult to maintain the negative pressure. Particularly desirable pore diameters are in the range of about 0.1 to 50 μm, and those having a narrow pore diameter distribution are particularly suitable. In particular, a cylinder having a pore diameter of about 10 μm, which is obtained by molding and firing porcelain clay having a large amount of quartz, is preferable.

These porous materials are usually molded into a cylindrical shape and used as a porous tube. The inner diameter, wall pressure, and length are not particularly limited, but if they are too small, the resistance when water flows is large, and if they are too large, a large amount of water is circulated in order to flush out the bubbles generated or mixed in inside. Will be required. Therefore, usually, the inner diameter is about 3 to 100 mm, preferably 5 to 50 mm, the wall pressure is about 1 to 30 mm, preferably 3 to 15 mm, and the length is not particularly limited, but it is flexible such as ceramics depending on the material. It is possible to reduce the number of connection points by making it short if it is scarce and easily broken by flexural stress, and lengthening it if it is highly flexible such as plastics material. To connect a plurality of porous pipes, it is common to use a tube such as polyvinyl chloride or polyethylene, or a pipe material, and it is convenient to use a metal pipe, a pipe connector or the like.

At the time of connection, it is preferable to use a tube or the like having a smooth interior, and to prevent the diameter of the tube from changing rapidly so that pressure loss is unlikely to occur. In the present invention, water is circulated under a negative pressure from the water tank provided upstream of the porous tube into the porous tube. In order to make a negative pressure, generally, for example, a water tank is provided at a position lower than the surface on which the porous pipe is laid, usually 30 cm to 3 m, the flow of water by a siphon is adjusted, and at the outlet of the pipe, Adjust the height of the open end to adjust the negative pressure and the flow rate of water generated in the pipe, or if the water tank is installed at a position higher than the surface where the porous pipe is laid, install a control valve The method of adjusting the circulation of the so that it becomes a negative pressure is adopted.

In the practice of the present invention, it is necessary to use water of a type suitable for the purpose of recovering raw water as the water in the water storage tank. It can be supplied, so there is no need to replenish it from outside the system. In the present invention, by adopting such a configuration, the evaporated raw water that has penetrated into the medium layer passes through the porous tube, is entrained in the water flowing in the porous tube, and is placed downstream of the water in the porous tube. It is collected in a water receiving tank provided so that

The water receiving tank is arranged at a lower position than the water receiving tank, and a necessary amount of water in the water receiving tank can be extracted and used for a desired purpose. At least a part of the water is stored in the water receiving means by the water circulating means. It can be supplied to a tank and used for distribution to a porous tube. The water circulating means is not particularly limited, and a pump or the like is used. The liquid level of the water tank is
It is preferable to keep it constant for stable operation.

FIG. 1 shows an embodiment of the water recovery device of the present invention, in which a raw water storage tank 1 is provided in a housing 2, a medium layer 3 is provided thereunder, and a porous tube 4 is provided. It is connected in series using the tube 5. Water is circulated from the water storage tank 6 to the porous tube 4 by a siphon, and the inside of the porous tube 4 is maintained at a negative pressure. The water discharged to the water receiving tank 7 is circulated to the water storage tank 6 by the pump 8.

In the present invention, it is not essential to return the water in the water receiving tank to the water storage tank and circulate it, and it is also possible to use it once as shown in FIG. In addition, as shown in FIG. 3, the above-mentioned water recovery device is installed in a plurality of stages from a high position to a low position, and the water in the water receiving tank at the high position is installed in the water tank of the water recovery device installed at the lower position. It is also possible to carry out water recovery continuously by making use of the difference in water head. In this case, it is particularly convenient for use in a place where there is a difference in height such as a sloping land or a building.

Here, for example, the first-stage water storage tank and the second-stage water storage tank may be provided separately, but preferably, as shown in FIG. 3, a tank 13 serving as both the water reception tank and the water storage tank. To do
The water receiving tank of the device at the former stage can be configured to be used as a water tank of the device at the latter stage (not necessarily the next stage, but may be the latter stage of the second stage).

For the water obtained by the present invention, if a material containing minerals is selected as the medium layer and hygiene management is sufficiently performed,
The elution of minerals makes it possible to secure water more suitable for drinking than water containing almost no salts. Further, the method of the present invention is particularly suitable as a method for obtaining irrigation water in a region such as a desert area where rainfall is small.

The apparatus of the present invention can obtain water not only on a sunny day but also on a cloudy day without using a special heat source as long as a wet environment is prepared. In other words, it is possible to function if there is an enclosure that can prevent the vaporized water vapor from scattering in the space due to the influence of the wind and create a state that can maintain a wet state, from seawater, groundwater with high salt concentration, etc. It is easy to secure low water.

When the present invention is used in combination with a solar water purifier, water can be efficiently recovered, but it is not always necessary to evaporate water by using solar heat, and there is no restriction on the steam generation method. . In order to increase the amount of purified water that can be obtained per unit time, raw water may be heated by a heater to generate steam.

[0022]

Example 1 Water was recovered using the water recovery device shown in FIG. That is, the housing 2 with a sloping roof made of transparent plastic is installed in a position where it does not become shaded so that sunlight can be projected. The bottom of the housing has a width of 25 cm, a length of 50 cm, and a depth of 5 cm, and salt water with a salt concentration of 3% is charged into a raw water storage tank 1 and a sand medium layer 3 with a thickness of 15 cm is provided below the raw water storage tank 1 and is exactly at the center. At the depth, four ceramic porous tubes 4 having an outer diameter of 25 mm, an inner diameter of 8 mm and a length of 150 mm were connected in series at the same depth using a polyvinyl chloride tube 5 and installed. The height of the water storage tank 6 is adjusted so that the position where the porous tube 4 exists is higher than the water surface of the water storage tank 6 by 30 cm. Water is flowed from the water storage tank 6 to the porous tube 4 by siphoning. The negative pressure inside the porous tube 4 was adjusted by the height of the open end portion released to the water receiving tank 7. Further, the water in the water receiving tank 7 was pumped up by the pump 8 so that the height of the water surface of the water tank was always constant. The water receiving tank 7 was provided with an overflow port, and a graduated cylinder 9 was installed under the overflow port so that the amount of overflowed water, that is, the amount of acquired water could be read. The amount of water flowing through the tube was 250 ml / min. When the temperature of the outside air was 30 to 32 ° C., it was operated for 6 hours during the day to collect water at a rate of 11.0 liter / m ² · day based on the area of the raw water storage tank.

In the experiment conducted in parallel under the same conditions except that the porous tube was not used, the apparatus of FIG. 4 was used, and the front side along the lower edge of the roof was slightly lower than the rear side. Condensed water flowing through the gutter 10 which was installed at an inclination was received by the funnel 11 and led to the graduated cylinder 9 by the tube 12, but the amount of water obtained in the graduated cylinder 9 was 2.8 liter / m 2. It was ² days.

[0024]

According to the present invention, water can be efficiently collected at low cost.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a water recovery device of the present invention.

FIG. 2 is a schematic view showing an example of a water recovery device of the present invention.

FIG. 3 is a schematic view showing an example of a water recovery device of the present invention.

FIG. 4 is a schematic view showing an example of a conventional solar water purifier.

[Explanation of symbols]

 1 Raw water storage tank 3 Medium layer 4 Porous pipe 6 Water storage tank 7 Water reception tank

Claims (4)

[Claims] 1. Raw water to be recovered is supplied to a raw water storage tank, the raw water is evaporated, the evaporated raw water is infiltrated into a medium layer, and a porous tube is embedded in the medium layer. A method for recovering water, characterized in that water is circulated under negative pressure and the evaporated raw water that has penetrated into the medium layer is recovered by passing through the porous tube. 2. A raw water storage tank for storing raw water to be recovered, a medium layer for infiltrating evaporated raw water, a porous pipe buried in this medium layer for collecting the evaporated raw water by passing through the porous pipe, and a negative pipe inside the porous pipe. A water recovery device comprising a water storage tank provided upstream of the porous pipe for supplying water under pressure, and a water receiving tank for receiving water flowing through the porous pipe. 3. A raw water storage tank for storing raw water to be recovered, a medium layer for infiltrating evaporated raw water, a porous pipe buried in the medium layer for collecting and passing the evaporated raw water, and a negative pipe in the porous pipe. In order to supply water under pressure, a water tank provided upstream of the porous tube, a water tank for receiving water flowing through the porous tube, and water in the water tank are supplied to the water tank. Water recovery device comprising a water circulation means for 4. A raw water storage tank for storing raw water to be recovered, a medium layer for infiltrating evaporated raw water, a porous pipe buried in the medium layer for collecting the evaporated raw water by passing through it, and a negative pipe in the porous pipe. In order to supply water under pressure, a multi-stage water recovery device comprising a water storage tank provided upstream of the porous pipe and a water receiving tank for receiving water flowing through the porous pipe A water recovery device that is configured in a shape and is configured so that the water receiving tank of the former device can be used as a water storage tank of the latter device.