JPS6351724B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a filter for separating and removing particulate matter floating in a liquid or gas that has a small particle size that is difficult to settle and separate, such as hydrophilic colloids and plant and animal plankton. be.

The activated sludge method is generally used to purify organic wastewater, in which organic matter is adsorbed onto activated sludge flocs and oxidized and decomposed, and then introduced into a settling tank where the flocs are coagulated and settled, and the supernatant liquid is discharged. In recent years, as standards for discharge into rivers have become stricter, tertiary treatment has become necessary, and at the same time, closed systems have been used to filter and reuse wastewater.

In order to reuse wastewater, it is necessary to separate soluble substances and extremely fine particles depending on the purpose, and separation methods using membranes such as reverse osmosis and ultrafiltration membrane methods are used. However, the main particles that make up the turbidity in wastewater are particles with a diameter of about 0.5 to 2 microns that are difficult to separate, and because they are sticky, they tend to stick to the surface of the filtration membrane and clog the membrane.

Therefore, in order to maintain the performance of the membrane, it is necessary to remove colloids and fine particles in the pre-membrane stage, and the conventional methods for this treatment include sand filtration, activated carbon filtration, and filtration around the rotating body. A precoat filtration method in which the filter is covered with a rough filter cloth or wire mesh and then thickly coated with diatomaceous earth as a filter slag layer, or a filtration method that uses a filter cloth made by stacking and pressing multiple layers of fibers such as resin, glass, or metal. Various methods are used. However, in the sand filtration method and the activated carbon filtration method, it takes time to backwash the filter after the flow path in the filter slag is blocked by captured particles, and a large amount of waste water is generated during the backwashing. Further, fine particles cannot be removed until the flow path is clogged to some extent, which shortens the actual filtration time and increases processing costs. In the pre-coating method, a large mesh filter cloth is used, so if the filter cloth is thin, the target particles cannot be captured, so it is necessary to make it thicker. The amount becomes very large. If a filter cloth with a mesh smaller than the particle diameter to be captured is used, the captured particles cannot be easily removed from the filter cloth and are disposable, resulting in higher processing costs. It was hot.

Therefore, as a filtration method that solves these problems, filter wires with a circular cross section are wound at regular intervals on a perforated irregular tube core, and the gaps between adjacent filter wires are used to remove fine particles in the fluid. A filter was proposed to remove the substance.

The present invention relates to improvements to this type of filter, and the technical issues associated with this type of filter are to maintain a constant line spacing, to accurately remove fine particulate matter, and to remove trapped particles by backwashing. The solution was to make it easy to remove, etc.
This will be explained below based on the drawings.

Figure 1 is a perspective view of the filter element, with irregularly shaped tube 1.
A filter wire 3 having a circular cross-sectional shape is wound around a perforated tube core body provided with a number of holes 2 for passing filtrate water or for venting compressed air for backwashing.
It is desirable that the irregularly shaped tube 1 has a curved surface to improve the flow of water and air between it and the filter wire 3. FIG. 2 is an enlarged sectional view showing the structure of the filter wire 3 of the filter of the present invention, in which a polymer baking film layer 5 is formed on the metal wire 4.
In this film, hard particles 6 having a uniform mesh size and which are resistant to corrosion are uniformly dispersed. Therefore, the fine particles 6 are exposed on the surface of the filter wire 3.

FIG. 3A is a partially enlarged cross-sectional view showing the winding state of the filter wire 3 of the filter of the present invention, in which the contact surface of adjacent filter wires has unevenness due to embedded particles 6, so a minute gap d is maintained. dripping Even if the degree of unevenness of the embedded particles on the wire surface varies, if the tension during winding is increased so that the wires are embedded into each other, the material of the particles will be harder than the baked film and the elastic modulus of the baked film will be lower. is so large that the unnecessarily protruding portions of the particles are forced into the coating, and the voids at the contact surfaces are made uniform, resulting in highly accurate slit spacing. The figure B is the filter wire 3.
This is another example of the winding state in which an auxiliary wire 7 is wound between adjacent filter wires. Similar to the filter wire 3, this auxiliary wire 7 is also provided with a baked film in which hard particles are dispersed on its surface. As a result, a uniform slit interval d ₁ is formed between adjacent filter lines, and a uniform slit interval d ₂ is formed between the filter line and the auxiliary line, resulting in a longer filtration channel and effective filtration. Area increases. In this case, the smaller the wire diameter of the auxiliary wire 7, the better the contact with the filter wire 3, and the slit interval _d2 can be made uniform.

If the slit between the filter wires becomes clogged due to fine particulate matter in the fluid, backwashing compressed air can be blown out from inside the perforated irregular tube core.
Remove trapped particles. FIG. 4 is a perspective view of the filter of the present invention, which has a purified water outlet 8 and a compressed air intake 9 for backwashing at both ends of the filter element.
If you are sharing it, you only need to use one end and keep the other end closed.

According to the present invention configured as described above, uniform slit gaps are formed between the wires due to the action of the hard particles protruding from the baked film on the surface of the filter wire, and the smaller the particle mesh, the finer the slit spacing becomes. This makes it possible to capture fine particles, making precision filtration possible and providing a high-performance filter. In addition, the filter wire is coated with a highly corrosion-resistant polymer baking film, so there is no need to use expensive metal materials that are highly corrosion-resistant, and the filter wire can be made thinner. Since the filtration area per unit area increases, the filtration cost becomes cheaper.

Next, examples of the present invention will be described.

Example 1 Filter wire in which a 0.4 mmφ copper wire surface was coated with a mixture of 85 parts polyurethane insulating paint and 15 parts α-alumina (Hokuia Random) 8000 mesh to form a 5μ thick polyurethane film. I got it. This filter wire is closely wound around the outer periphery of a perforated hexagonal titanium tube with a diagonal of 12 mm and a wall thickness of 0.6 mm. After fixing the terminal, a purified water outlet and a compressed air intake for backwashing are provided at both ends. A filter according to the present invention was created.

In order to investigate the particle capture performance of the filter, 6000 mesh α-alumina with a clear particle size distribution (containing 27% particles of 1μ or less and 4% particles of 0.5μ or less) was dispersed in water and suspended at 100mg/L. I made a liquid. This suspension was filtered using constant pressure filtration at 0.7 Kg/cm ² and the filtrate was collected. In order to measure the degree of purification of the obtained filtrate, it was filtered with a membrane filter (filter paper that can capture particles down to a particle size of 0.3μ is used), and the particulate matter concentration was measured, and it was found to be 10mg/L. In the end, I was able to reach my intended goal. In other words, the accuracy of the filter in this example is 0.5
It is possible to purify a suspension containing 27 mg/l of particles of ~1 μ to a solution containing 10 mg/l of particles of 0.3 μ or larger, indicating that particles of 1 μ or larger can be completely captured.

After closing the slit interval with captured particles, 4Kg/
After backwashing with cm ² of compressed air, the filtration rate returned to its initial value. This confirms that the trapped particles were almost completely removed.

Example 2 The α-alumina-dispersed polyurethane insulating paint used in Example 1 was applied to the surface of a 0.08 mmφ copper wire to form a 4μ thick polyurethane film, and the wire was used as an auxiliary wire. A filter according to the present invention having slit intervals d ₁ and d ₂ was produced by winding the filter wire between the wires wound on the perforated hexagonal irregular titanium tube obtained in .

In order to examine the particle capture performance of the filter, a suspension was prepared under the same conditions as in Example 1, and a filtrate was collected. This was then filtered using the same membrane filter, and the particulate matter concentration was measured and found to be 0.4 mg/l. In this example filter,
0.3μ from a suspension containing 4mg/l of particles smaller than 0.5μ
It is possible to purify the liquid to a level containing 0.4 mg/l of particles of 0.5 μ or more, indicating that particles of 0.5 μ or more can be completely captured.

After closing the slit interval with captured particles, 5Kg/
After backwashing with cm ² of compressed air, the filtration rate returned to its initial value. This confirms that the trapped particles were almost completely removed.

As explained above, since the filter of the present invention can be backwashed with compressed air, the amount of waste water generated by washing is reduced, and at the same time, it can withstand continuous use.
Furthermore, since it has excellent corrosion resistance, it can be used for a long time, and filtration costs are reduced, which has great effects. Therefore, it can be applied not only to water purification but also to all fields where membrane filters are currently used for filtration.

[Brief explanation of the drawing]

1 is a perspective view of a filter element, FIG. 2 is an enlarged sectional view of a filter wire used in the filter of the present invention, FIGS. 3A and 3B are partially enlarged sectional views showing the winding state of the filter wire, FIG. 4 is a perspective view of the filter of the present invention. 3...Filter wire, 4...Metal wire, 5...Polymer baking film, 6...Dispersion particles, 7...Auxiliary wire.

Claims (1)

[Claims] 1. In a filter in which a filter wire with a circular cross section is tightly wound on a perforated irregular tube core body, and fine particulate matter in the fluid is removed between adjacent filter wires, as the filter wire, A filter characterized by using a wire on which a baked polymer film with a large elastic modulus is formed by dispersing hard particles having a uniform fine mesh on the surface of the metal wire.