JPS6261324B2 - - 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 waste water 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 extremely large. When using a filter cloth with a mesh smaller than the particle size to be captured, 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 to solve these problems, filter wires with a circular cross-section are wound at regular intervals on a perforated polygonal 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.

FIG. 1 is a perspective view showing an example of a filter element, and shows a perforated polygonal tube core with a large number of holes 3 on each side of the polygonal tube 2 for passage of filtered liquid or for venting compressed air for backwashing. A filter wire 4 having a circular cross section is wound around the wire 1 . It is desirable that the polygonal tube 2 be formed with each side curved inward to improve the flow of water and air between the polygonal tube 2 and the filter wire 4. Note that the polygonal tube 2 may be any polygonal tube having a triangular shape or more. FIG. 2A is a partially enlarged sectional view showing the winding state of the filter wire of the filter of the present invention, in which an auxiliary wire 5 is wound between adjacent filter wires 4. The auxiliary wire 5 needs to have a smaller wire diameter than the filter wire 4. A minute gap d is formed at the joint surface between the filter wire 4 and the auxiliary line 5, and this gap traps fine particulate matter. In addition, as shown in FIG. 2B, a supporting wire 6 for maintaining a constant interval between adjacent filter wires 4 is wound closely around the filter wire 4 on the core body 1 , and the adjacent filter wires 4 are wound closely together. By winding the auxiliary wire 5 between the wires 4 and 4, fine particulate matter that could not be captured by the minute gap d1 formed at the joint surface of the filter wire 4 and the auxiliary wire ₅ will be removed from the filter wire. A minute gap d ₂ formed at the joint surface between the wire 4 and the support wire 6
This allows for more effective filtration. Specifically, for example, the slit spacing d ₁ , d ₁ between the filter wire and the auxiliary wire or the slit spacing d ₂ between the filter wire and the support wire is 0.5μ or less,
The surface of the filter wire 4 or, depending on the case, the surface of the auxiliary wire 5 or the supplementary wire 6 is chemically or mechanically provided with irregularities. Fig. 3 is a perspective view of the filter of the present invention, which has a purified water outlet 7 and a compressed air intake 8 for backwashing at both ends of the filter element, and if they are shared, only one should be used, and the other should be sealed. .

According to the present invention configured as described above, when the conventional filter wire is wound with poor accuracy or when compressed air for backwashing is blown out from within the core body 1 , The wire tended to float and cause variations in the slit spacing, but by winding the auxiliary wire 5, which has a smaller wire diameter than the filter wire, between adjacent filter wires 4. Since the auxiliary wire 5 presses and fixes the filter wire 4, the winding accuracy can be corrected, and the slit interval d between the filter wire 4 and the auxiliary wire 5 makes it possible to remove fine particles of 0.5μ or less. It is possible. In addition, when blowing out compressed air for backwashing, if the wire diameter of the auxiliary wire 5 is selected so that elongation within the elastic limit is expected due to the air pressure, the slit interval d between the filter wire 4 and the auxiliary wire 5 will be increased, and the captured wire will be This makes it possible to easily remove the particles, allowing continuous operation, and greatly reducing filtration costs.

Next, examples of the present invention will be described.

Example 0.4mmφ stainless steel wire was treated with 70 parts of concentrated nitric acid,
Electrolytic corrosion is carried out to 0.5μ by AC electrolysis in an electrolytic solution containing 30 parts of glacial acetic acid at a current density of 20A/dm ² to obtain a filter wire with a surface roughness of 0.5μ or less. this,
A wire is tightly wound around the outer periphery of a perforated hexagonal stainless steel tube with a diagonal of 12 mm and a wall thickness of 0.6 mm. Furthermore, a stainless steel wire with a smooth surface of 0.06 mmφ is wound between the adjacent filter wires, and the terminal is fixed to obtain a filter element. A purified water outlet and a compressed air intake for backwashing are provided at both ends.

In order to investigate the filtration performance of this filter, we used 6000 mesh α-alumina (0.5
(containing 4% of particles smaller than μ) were dispersed in water to create a suspension with a particle concentration of 100 mg/. This suspension was filtered using constant pressure filtration at 0.7 Kg/cm ² to collect a filtrate. 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 0.2mg/
It was hot. In other words, it was possible to purify a suspension containing 4 mg of particles of 0.5 μ or less to a liquid containing 0.2 mg of particles of 0.3 μ or more, thus achieving the intended purpose of the present invention. .

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.

As explained above, the filter of the present invention has excellent effects such as having uniform slit intervals and being able to accurately remove fine particulate matter, and easily removing trapped particles by backwashing. The present invention can be applied not only to water purification but also to processes in the food industry, such as separating yeast of 1 μm or more from beer, and the present invention will greatly contribute to industry.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a filter element, FIGS. 2A and 2B are partially enlarged sectional views showing the winding state of the filter wire of the filter of the present invention, and FIG. 3 is a perspective view of the filter of the present invention. 1 ... Perforated polygonal tube core, 4... Filter line, 5... Auxiliary line, 6... Support line, 7... Purified water outlet, 8... Air intake for backwashing, d,
d ₁ ...Slit interval between the filter line and the auxiliary line, d ₂ ...Slit interval between the filter line and the support line.

Claims (1)

[Claims] 1. A perforated polygonal tube core in which each side of the polygonal tube 2 is distorted inward to form a curved surface, and fluid passage holes are bored in the curved surface in order to remove fine particulate matter from the fluid. In a filter of the type in which a filter wire 4 having a circular cross-sectional shape is wound on a filter wire 4 and filtering is performed between the wires, an auxiliary wire having a smaller wire diameter than the filter wire is placed between adjacent filter wires 4. A filter characterized in that a wire 5 is wound around the wire 5 and particulate matter is captured by a minute gap d formed at the joint surface between the filter wire 4 and the auxiliary wire 5.