Filter (filter) is an indispensable device in the conveying pipe, usually mounted on the pressure reducing valve, pressure relief valve, water valves, Fang Gong filter another equipment for equipment at the entrance. Filter by cylinder, stainless steel mesh, emission, transmission device and electric control parts. Of water through the filter to be processed after the filter cartridge, the impurities are blocked, when cleaning is needed, just take out the removable filter cartridges, reload after the treatment, therefore, is extremely easy to use and maintenance.

Filter technology has been applied in the production of ancient China, 200 BC there are fibres made of paper. 105 ad by Cai Lun improved papermaking process. He will fiber pulp during paper swing on the dense thin bamboo curtain. Through the blinds slot filtration, a thin layer of wet pulp from bamboo surfaces, dry as paper.

First most of the filter for the gravity filters, then pressure filter is used to improve the speed of filtration, and then there was a vacuum filter. Early 20th century invention of rotary drum vacuum filter for filtering operations continuous. Since then, various types of filters have appeared in a row. Batch filter (for example, plate-and-frame filter press) was developed for its automated operation, filter area is growing. To get the moisture content low residue, filter has been developed for mechanical press.