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What is the working principle of the plate cardboard filter?
- 2020-04-18-

The container is divided into upper and lower chambers by the filter medium of the plate-type cardboard filter, and the lower chamber constitutes a simple filter. The suspension is added to the upper chamber, and enters the lower chamber through the filter medium under pressure to become filtrate, and the solid particles are trapped on the surface of the filter medium to form Filter residue (or filter cake). During the filtration process, the filter residue layer on the surface of the filter medium gradually thickens, the resistance of the liquid passing through the filter residue layer increases, and the filtration speed decreases. When the filter chamber is full of filter residue or the filtration speed is too small, stop filtration , remove the filter residue and regenerate the filter medium to complete a filter cycle.

The liquid passing through the filter residue layer and the filter medium must overcome the resistance, so there must be a pressure difference between the 2 sides of the filter medium, which is the driving force to realize the filtration of the plate filter. Increasing the pressure difference can speed up the filtration, but under pressure The post-deformed particles are easy to block the pores of the filter medium when the pressure difference is large, and the filtration is slowed down. There are many industrial chains in China, the production concentration of the industry is low, the research and development capabilities of high-end products are low, and the manufacturing technology level of the filter press industry is low, etc. The phenomenon still exists, and the import and export trade deficit continues to expand. The next few years will be a period of high-speed shock in the filter press industry. The direct consequence of this high-speed shock is the expansion of the trend of polarization in the brand camp. It is expected that in the next few years There are absolutely not so many companies that can really survive in the market. But this high-speed shock in the filter press industry will bring huge opportunities, and the result of the shock will make the market operation more rational. High-end electric filter presses are localized The road is unusual "bumpy". Basic parts have become a shortcoming that restricts the development of China's filter press manufacturing industry to high-end. During the ten-25 period, the government will continue to increase the localization of high-end equipment parts for filter presses. With the continuous development of the market, there are three types of suspension filtration: filter residue layer filtration, deep filtration and sieve filtration.

①Filter residue layer filtration: In the initial stage of filtration of the plate cardboard filter, the filter medium can only retain large solid particles, and the small particles pass through the filter medium with the filtrate. After the initial filter residue layer is formed, the filter residue layer plays a major role in filtration. Particles are retained, such as in plate and frame filter presses.

②Deep filtration: The filter medium of the plate cardboard filter is thicker, the suspension contains less solid particles, and the particles are smaller than the pores of the filter medium. During filtration, the particles are adsorbed in the pores after entering, such as porous plastic tube filters, sand filter filter


③Screening: The solid particles retained by the plate-type cardboard filter are larger than the pores of the filter medium, and the solid particles are not adsorbed inside the filter medium. For example, the rotary drum filter screen filters out the coarse impurities in the sewage. The three ways often occur simultaneously or in succession.