| 摘要 |
PURPOSE:To prevent generation of clogging in an early stage by providing many projecting parts on the surface of the base part of a filter medium consisting of fibrous material and making the base part fine and making the projecting parts coarse and forming both the base part and the projecting parts into a continuous integral structure. CONSTITUTION:A filter medium consisting of fibrous material is manufactured into sheets and then this filter medium is impregnated with resin and before this resin is cured, the filter medium is fed to a projection forming roll 10 consisting of a cylindrical roll provided with many projections 9 on the surface or a gear roll and furthermore heated. By this manufacture, many projecting parts 6 are provided on the surface of the base part 7 of the filter medium 5 consisting of fibrous material and the base part is made fine and the projecting parts 6 are made coarse and both the base part 7 and the projecting parts 6 are formed into a continuous integral structure. As a result, a minute adhesive layer is not interposed between the coarse part and the fine part and generation of clogging in an early stage is prevented. Further separation efficiency is improved because the recessing parts formed between the projecting parts act as dust reservoirs. |
