JPS588914B2 - Seawater desalination equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to a seawater desalination device.

Devices for desalinating seawater are in demand, especially in the Middle East, where water resources are scarce.

Recently, Japan has been asked to manufacture seawater desalination equipment for use in areas such as Iran, but all of the equipment manufactured is a method of distilling seawater to obtain fresh water.
This is considered to be the commonly used method at present.

However, in the method of obtaining fresh water by distilling seawater, the equipment must be large-scale, and there are problems in terms of economic aspects such as construction costs and operating costs, and operational management.

As a result of intensive research into a method for easily obtaining fresh water from seawater using a simple device using a method such as furnace filtration, the present inventor discovered that a reverse osmosis membrane can be used as a furnace material.

Here, the term "reverse osmosis membrane" refers to a membrane that has the property of allowing solvent water to pass through a semipermeable membrane by applying pressure higher than the osmotic pressure of a solution, so that the solute remains on the membrane surface and is concentrated.

Therefore, in the present invention, the term reverse osmosis membrane includes all membranes having the above properties.

If the reverse osmosis membrane described above is configured in a cylindrical shape and seawater is put inside and pressurized, the fresh water as a solvent will be filtered out of the membrane, while the salt salts as a solute will remain inside the membrane, resulting in a preference for freshwater to seawater. This makes it possible to separate and collect salt and salt separately.

However, since natural seawater generally contains various contaminants, when this seawater is filtered through a reverse osmosis membrane, these contaminants may adhere to the surface and inside of the furnace material within a short period of time. It accumulates and clogs the furnace material, making subsequent filtration impossible.

Therefore, this lumber must be constantly cleaned during the furnace.

However, the equipment used for this cleaning must not be one that allows the vacuum cleaner to come into direct contact with the surface of the offshore wood, and must not be one that temporarily suspends the swamping process and cleans by backflowing. It won't happen either.

In the former case, the filter material will be worn out and damaged, and in the latter case, there will be not only the disadvantage that the purpose of offshore passing must be interrupted during that time, but also various operational difficulties. Therefore, equipment for cleaning off-shore wood must be able to operate permanently and separate and collect only fresh water from seawater without clogging the furnace material. There must be.

The present invention has been made in view of the above points, and its object is to provide a device that can permanently and continuously separate and collect fresh water from seawater using a simple device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in further detail below with reference to the accompanying drawings showing one embodiment of the present invention.

1 and 2 show the overall structure of the device according to the present invention. In the figures, 1 is an outer cylinder, and inside the outer cylinder 1, a reverse osmosis membrane 2 is held in a predetermined position by a frame 3. The outer cylinder 1, the reverse osmosis membrane 2 and the frame 3 are arranged in a perfect circular cylindrical shape at intervals.
The space formed by
is formed.

On the other hand, a funnel-shaped solids collection tank 5 is fixed to the lower end of the frame 3 forming the reverse osmosis membrane 2 in a cylindrical shape.

In this way, the outer cylinder 1, the cylindrical reverse osmosis membrane 2, and the solids collection tank 5 constitute a seawater separation tank.

Further, 6 is a disk that seals the open upper end of the seawater separation tank, and the disk 6 has an inflow port for introducing seawater into the cylinder formed by the reverse osmosis membrane 2 and the frame 3. A tube 7 is provided.

Further, a rotary shaft 8 is inserted through the center of the disk 6 and is rotatably supported, and a cleaner 10 is attached to the rotary shaft 8 via an arm 9.

Reference numeral 11 denotes a level pipe provided at the upper part of the cylindrical frame 3, which drains the seawater when the amount of seawater inside the cylinder formed by the reverse osmosis membrane 2 and the frame 3 increases to reach the highest level of the seawater. This is to keep the level constant.

Reference numeral 12 denotes an outlet provided at the lower part of the outer cylinder 1, and is for taking out the fresh water that has been filtered from the seawater and collected in the freshwater recovery chamber 4. It is collected via the outflow tube 13 held in the tank.

Therefore, the level of fresh water in the fresh water recovery chamber 4 is always the same as the height of the outflow pipe 13, and can be maintained at a predetermined level by changing the height of the outflow pipe.

The basic feature of the present invention is that a reverse osmosis membrane is used as the furnace material, and the surface and inside of this P material are cleaned to prevent clogging, so that seawater can flow continuously over time. The cleaning mechanism for F material and the device therefor.

This will now be explained using drawings.

3 to 5 show the structure of a vacuum cleaner according to the present invention, in which the cross section of the cleaner 10 is the shape of a leading edge portion obtained by dividing a hollow airfoil into approximately half, and its plane is the lower side 14.
has a rectangular shape that is slightly longer than the upper side 15.

Further, in this embodiment, the upper side 15 is also open, but it is necessary that at least the opposite side 17 of the front edge 16 and the end of the lower side 14 are open.

Since the leading edge 16 is the tip of the airfoil, it forms an arc with a small diameter, and the outer surface 18 following this forms an arc with a radius slightly shorter than the radius of the perfectly circular cylindrical inner surface of the reverse osmosis membrane. 19 is a flat surface.

Two cleaners 10 having the above-mentioned shape are considered as a set,
It is arranged upright in the center of the cylinder of the reverse osmosis membrane so that its outer surface 18 faces the inner surface of the cylinder of the reverse osmosis membrane 2, and the upper side 15 is placed upward and the lower side 16 is placed downward inside the cylinder of the reverse osmosis membrane. An inner surface 19 of a cleaner 10 is fixed to opposite ends of two arms 9 fixed to a rotating shaft 8.

Accordingly, the cleaner 10 is rotated in the direction of the arrow while maintaining a position in which the outer surface 18 is as close as possible to the cylindrical inner surface of the reverse osmosis membrane but not in contact with it, thereby touching the inner surface and interior of the reverse osmosis membrane 2. Clean and prevent clogging.

Here, to explain the principle of the cleaning mechanism of the cleaner 10, if the cleaner 10 having the above-mentioned structure is rotated at high speed with its outer surface 18 close to the reverse osmosis membrane 2, this cleaner Negative pressure is generated at the rear end of the cleaner 10, and if there are any contaminants attached or deposited on the inner surface and inside of the reverse osmosis membrane 2, they are all removed by this strong negative pressure and removed from the hollow space of the cleaner 10. The reverse osmosis membrane 2 is constantly cleaned by suction inside, and clogging is completely prevented.

Furthermore, in this device, the upper side 15 of the cleaner 10
is shorter than the lower side 16 and has a smaller width at the top.

Therefore, the negative pressure generated at the rear end is also small at the top and small at the bottom, and the internal volume is also small at the top and small at the bottom.

Therefore, the contaminants sucked into the cleaner 10 are also sucked and moved from the top to the bottom inside the cleaner 10, and are discharged from the bottom end to the bottom and collected in the solid content collection tank 5. There is no longer any disadvantage that the particles may move and be deposited near the surface of the reverse osmosis membrane 2 again.

In addition, in order to rotate the cleaner 10 at high speed as described above, the seawater inside the reverse osmosis membrane 2 is also rotated at a considerably high speed in the same direction, although at a slower speed than that, so the centrifugal force causes the reverse osmosis membrane to rotate. Pressure is generated against the reverse osmosis membrane 2, and even without special pressure, only fresh water is passed through the reverse osmosis membrane 2, and salts, contaminants, etc. remain on the surface of the reverse osmosis membrane 2.

That is, there is an advantage that the desired purpose of F filtration and cleaning of the reverse osmosis membrane can be achieved at the same time.

Note that the rotation speed of the cleaner is appropriately selected depending on the state of accumulation of contaminants on the reverse osmosis membrane, the degree of contamination of seawater, and the like.

The solids such as salts and contaminants collected in the solids collection tank 5 are appropriately discharged, and a device for simplifying this discharge has been further devised in this apparatus.

That is, the ♀ portion of the funnel-shaped solid content collection tank 5 is formed into a cylindrical body 20 having a vertically rectangular cylindrical shape and a central portion thereof bulging into a lateral cylindrical shape.

In the cylindrical portion 21 of the cylindrical body 20, two cooperating swirlers 22a and 22b, both of which have horizontal and parallel central axes, are disposed.

The surfaces of the rollers 22a and 22b are made of an elastic material such as rubber, and the circumferences of the rollers 22a and 22b are sealed with a cylindrical part 21 except for the lower and upper parts, and the seawater in the solids collection tank is sealed. Cylindrical part 21 to prevent leakage.
Rotates by sliding on the inner surface of the

Further, two scraping plates 23a and 23b having the same length as the rollers 22a and 22b are provided inside the cylinder 20 below the rollers 22a and 22b, and their upper ends are respectively connected to the rollers 22a and 22b. It is brought into contact with the surface of 22b.

Now, if the two rollers 22a and 22b are rotated in the direction of the arrow, the seawater in the solid content collection tank will not flow downward, but if solid content is mixed in it, it will accumulate on the rollers. It moves downward between the rollers 22a and 22b, is scraped off by the scraping plates 23a and 23b, and falls, making it possible to remove the solid content very easily.

By the way, since the raw material processed by this device is natural seawater, it is recommended to use titanium material in the parts that come into contact with seawater, both from the viewpoint of corrosion and from the viewpoint of light weight and high strength.

As described above, the seawater desalination apparatus according to the present invention uses a reverse osmosis membrane as a tear material for separation, has a cylindrical shape, and has at least the rear end close to the inner surface of the reverse osmosis membrane. By rotating the cleaner, which has a hollow wing-shaped cross section with an open bottom end, it simultaneously applies pressure to the reverse osmosis membrane and removes salts and other substances accumulated on the surface and inside of the reverse osmosis membrane, easily and permanently. It has the advantage that it can simultaneously separate fresh water from seawater and simultaneously clean the reverse osmosis membrane and prevent clogging.

Furthermore, by forming the lower part of the solid content collection tank into a cylindrical shape and by providing two cooperating rollers that come into sliding contact with the inner surface of the tank, the solid content accumulated at the bottom of the solid content collection tank can be easily discharged.

[Brief explanation of the drawing]

The attached drawings illustrate the structure of one embodiment of the device according to the present invention, and FIG. 1 is a vertical side view of the entire device, FIG. 2 is a cross-sectional plan view of the device as seen from A-A, and FIG. 3 is a plan view of the cleaner fixed to the rotating shaft, and FIGS. 4 and 5 are side views of the cleaner shown in FIG. 3, viewed from directions perpendicular to each other. 2 is a reverse osmosis membrane, 3 is a frame body, 4 is a freshwater collection chamber, 5 is a solids collection tank, 8 is a rotating shaft, 10 is a cleaner, 22a, 2
2b is a roller, and 23a and 23b are scraping plates.

Claims (1)

[Claims] 1. Reverse osmosis membranes 2 are arranged in a cylindrical shape at predetermined intervals in an outer cylinder 1, and the space formed by the reverse osmosis membrane 2 and the outer cylinder 1 is sealed at the bottom. In addition to forming a freshwater recovery chamber 4, a funnel-shaped solids collection tank 5 is fixed to the lower end of the reverse osmosis membrane 2 having a cylindrical shape to form a seawater separation tank, while a hollow airfoil-shaped cross section is formed. The cleaner 10 has a shape of a front edge portion which is roughly divided into halves, a rectangular plane in which the lower side 14 is slightly longer than the upper side 15, and at least the opposite side 17 of the front edge 16 and the end of the lower side 14 are open. is placed close to the inside of the reverse osmosis membrane 2 so that the outer surface 18 of the cleaner 10 faces the inner surface of the reverse osmosis membrane 2 having a cylindrical shape, and the cleaner 10 is placed along the reverse osmosis membrane 2. A seawater desalination device that rotates. 2. The lower part of the funnel-shaped solid content collection tank 5 is formed into a cylinder 20 having a vertical rectangular cylinder shape with a horizontal cylindrical bulge at the center, and inside the cylindrical part 21 there is a cylinder whose central axis is horizontal and parallel. Two cooperating rollers 22a and 22b whose surfaces are made of an elastic material are brought into sliding contact with the inner surface of the cylindrical portion 21 to prevent the seawater in the circular collection tank 5 from leaking. Two scraping plates 23a and 23b are provided and are in contact with the rollers 22a and 22b, respectively.
22b. The device according to claim 1, which is provided on the lower side of the device 22b.