Beijing swimming pool filter side sand tank
Sand tank filtration principle:
A certain scale of quartz sand is generally placed in the sand aquarium. Within a certain range, the size and specifications of the quartz sand are different. In the sand aquarium, the quartz sand is arranged from top to bottom and from small to large. When filtering normally, the water is from the sand. The upper level enters and the lower level exits. When water flows through the filter layer from above, part of the solid suspended matter in the water enters the tiny holes formed by the upper filter material and is trapped by the surface layer of the filter material by adsorption and mechanical retention. At the same time, these suspended solids are trapped Overlapping and bridging effects occur again, as if a thin film is formed on the surface of the filter layer, which continues to filter suspended substances in the water. This is the so-called membrane filtration of the surface layer of the filter material. This filtering effect is not only on the surface of the filter layer, but also has this interception effect when water enters the intermediate filter layer. In order to distinguish it from the filtration of the surface layer, this effect is called osmotic filtration.
In addition, because the sand particles are closely arranged with each other, when the suspended particles in the water flow through the tortuous pores in the sand layer, they will have more opportunities to collide and contact with the surface of the filter material and time. Therefore, The suspended matter in the water adheres to the flocs on the particle surface of the sand layer to cause contact coagulation.
In summary, the filtration of the sand tank is to further purify the water through the process of membrane filtration, permeation filtration and contact filtration.