| 摘要 |
PROBLEM TO BE SOLVED: To provide a pressure filtration method capable of removing not only solid sediment but also liquid impurities such as oil microparticles and particularly useful for removing ink, paper powder, oil components or the like mixed in wetting water used in an offset press or in a rotary press, whereby the suitability of the wetting water for use in printing is enhanced. SOLUTION: The pressure filtration method to be used in a pressure filtration apparatus comprises filling an air-tight housing with an impurity-containing mother liquid using pressure, forcefully pressing the mother liquid to a filter net disposed on a rotary drum to allow the filtrate alone to pass therethrough while allowing the impurities present in the mother liquid to be captured on the circumferential face of the filter net disposed on the rotary drum by their collision with the filter net, scraping off the captured impurities from the circumferential face of the filter net by a brush, allowing the impurities thus scraped off to ascend in the air-tight housing and to gather in the upper part thereof, and discharging the gathering impurities to the outside periodically or on demand. COPYRIGHT: (C)2009,JPO&INPIT
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