Patent Application
20110278217
The present invention relates to a screen device using wedge wires.
A solid-liquid separation apparatus using screens having slits of specified dimensions provided among wedge wires, by forming wedge wires of metal wire rods of a wedge-shaped section in multiple rows in parallel, is widely used in various industrial fields, for the purpose of removal of floating matter in a wastewater treatment plant, solid-liquid separation of crude liquid in treatment process of various industrial waste water in paper pulp industry, food industry, textile industry, chemical industry, and others.
The slit spacing width between wedge wires in a screen device using wedge wires is generally 0.5 mm (500 microns), but solid matter is likely to deposit and grow on the side surfaces of the wedge wires on the back side of the screen, causing clogging of slits, and the solid-liquid separation performance may be lowered.
To prevent such screen clogging, it has been proposed to use a clogging preventive device for cleaning the slits of the screens by moving forward a brush into the wedge wires from the back side of the screen (see patent documents 1 to 3).
Even in such conventional wedge wire screen having the clogging preventive device by using the brush, when the slit spacing width is smaller than 0.2 mm (200 microns), the slits are loaded and clogged due to surface tension of crude liquid or waste water flowing on the screen surface, and the solid-liquid separation performance is extremely lowered, and liquid cannot be separated and removed sufficiently. It was hence considered to be difficult to be applied to solid-liquid separation of crude liquid or waste water of small particle size of solid matter.
It is hence an object of the present invention to solve the conventional problems, and provide a wedge wire screen device capable of preventing lowering of solid-liquid separation performance, without allowing clogging of slits due to surface tension of crude liquid or waste water flowing on the screen surface, even when the slit spacing width of the wedge wires is smaller than 0.2 mm (200 microns).
To solve the above problems, the present invention relates to a wedge wire screen device characterized by a configuration in which a multiplicity of wedge wires of metal wire rod of a wedge-shaped section are arrayed in parallel, and slits of a specified dimension are provided among the wedge wires, and the entire surface of the wedge wires is coated with a hydrophilic paint.
The hydrophilic paint is preferred to be an inorganic paint mainly composed of sodium silicate, aluminum oxide, titanium oxide, and water.
The hydrophilic paint is applied on the entire surface of the wedge wires by baking-painting at 190 ° C. to 220 ° C.
In the wedge wire screen device of the present invention, the slit spacing width of the wedge wires is 100 microns to 300 microns, and the coat film thickness of coating of the hydrophilic paint is preferred to be 5 microns to 20 microns.
According to the present invention having such configuration, since a liquid film layer of crude liquid or waste water flowing on the wedge wire screen surface is peeled by the hydrophilic action of the hydrophilic paint applied on the wedge wires, the surface tension of the liquid film layer is weakened, and the slits among the wedge wires are effectively prevented from being clogged by the liquid film layer, and the liquid passes through the slits easily and is separated. Therefore, if the slit spacing width of the wedge wire screen is as small as 100 microns to 300 microns, the liquid portion of crude liquid or waste water easily passes through the slits and is separated, and solid-liquid separation of crude liquid or waste water of very small particle size of solid matter is realized, which was considered difficult with the conventional wedge wire screen.
Moreover, it is advantageous from the viewpoint of manufacturing cost because it can be realized only by coating the surface of the wedge wires with the hydrophilic paint.
A preferred embodiment of the present invention is more specifically described below while referring to the accompanying drawings.
After the wedge wire screen 1 is composed in this manner, the entire surface of each wedge wire 2 is coated with a hydrophilic paint 5.
The hydrophilic paint 5 is an inorganic paint mainly composed of sodium silicate, aluminum oxide, titanium oxide, and water, and by baking and painting at 190 ° C. to 220 ° C., it is applied on the entire surface of each wedge wire 2, and the coating film thickness is preferably 5 microns to 20 microns.
In the meantime, as shown in
Patent document 1: Japanese Utility Model Publication No. S64-4418
Patent document 2: Japanese Utility Model Publication No. S54-45575
Patent document 3: Japanese Patent Publication No. S59-39166
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2010-110029 | May 2010 | JP | national |
