Mechanical filter

The fully automatic multi-media filter, also known as a mechanical filter, is mainly used to remove suspended matter and solid particles in water. Suspended solids are non-colloidal solids that are insoluble in water and can settle when conditions are suitable. The suspended solids are intercepted by the filter, and the weight difference before and after the filter medium intercepts the suspended solids is used as the basis for measuring the function of the filter. The filter medium generally uses a filter medium with D=0.5-1.0mm. Single-layer filtration, double-layer filtration and multi-layer filtration can be used according to the impurity components in the water.

The multi-media filter materials in the filter are high-quality uniform-grained gravel, quartz sand, magnetite, anthracite, granular activated carbon, KDF, granular porous ceramics and other filter materials, which can be selected and used according to actual needs. These filter materials are scientifically and orderly distributed in the filter tank according to their specific gravity and particle size. For example, anthracite with small specific gravity and slightly larger particle size is placed on the top layer of the filter bed, quartz sand with moderate specific gravity and small particle size is placed in the middle layer of the filter bed, and gravel with large specific gravity and large particle size is placed on the bottom layer of the filter bed. Such a ratio ensures that the filter will not produce chaotic layer phenomenon when backwashing, thereby ensuring the interception capacity of the filter material.

Multi-media filters are widely used in water treatment processes. They can be used alone, but most of them are used as pre-filtration for deep water treatment (exchange resin, electrodialysis, reverse osmosis). Multi-media filters are mainly composed of the following parts: supporting pipelines and valves. The filter body includes: ① simplified body; ② backwash air pipe; ③ water distribution assembly; ④ support assembly; ⑤ filter material; ⑥ exhaust valve (external), etc.

mechanical filters (also called  Multi-media filters ) use layers of anthracite, sand, finely crushed garnet or other materials as the bed. A typical multi-media filter is shown in the figure: The top layer of the bed is composed of the lightest and coarsest grade materials, while the heaviest and finest grade materials are placed at the bottom of the bed. The principle is to filter by depth - larger particles in the water are removed at the top layer, and smaller particles are removed at a deeper level in the filter medium. This allows the water quality to reach the standard after coarse filtration.

The multi-media filter can remove large suspended solids in the water, thereby reducing the SDI value of the water and meeting the water quality requirements of deep purification. The equipment has the characteristics of low cost, low operating cost, simple operation; the filter material can be used multiple times after backwashing, and the filter material has a long service life.

Multi-media filters are widely used in water treatment processes, mainly for water treatment turbidity removal, water softening, electrodialysis, reverse osmosis pretreatment, and can also be used for surface water and groundwater sediment removal.