In ancient China, filtration technology has been applied in production. In 200 BC, paper made from plant fibers was available. In 105, CAI lun improved the method of making paper. In the process of making paper, he undulates the pulp from plant fibers into a dense curtain of thin bamboo. Water through the gap of the bamboo curtain filter, a thin layer of wet pulp left in the bamboo curtain surface, dry after the paper.Most of the earliest filtration is gravity filtration, and then use of pressure filtration to improve the filtration speed, and then the emergence of vacuum filtration. The rotary drum vacuum filter invented in the early 20th century realizes the continuous filtration operation. Since then, various types of continuous filters have appeared. Intermittent filters (e.g., plate-frame filters, etc.) have been developed for automated operation, with larger and larger filtration areas. In order to obtain the filter residue with low moisture content, the filter of mechanical press has been developed.