Multi-media filter MMF is suitable for removing suspended matter, sediment and mechanical impurities in water. Most of the impurities it removes, with or without the use of flocculants or pre-purification units, are dust, poisons, iron oxide, manganese, organics, and chromaticity. Filter material is refined quartz sand and anthracite. Work press of filter is less than 0.6Mpa when suspended substance is less than 20mg/L, and the suspension in water is less than 2mg/L. 

Structural Characteristics

• The upper water inlet device is horn type water distribution device;

• The lower drainage device is a porous plate with water cap or a domed porous plate with quartz sand cushion;

• When the diameter of the equipment is ≥1500mm, the bottom manhole is on the side of the lower head;

• The internal surface of the equipment is anticorrosive with black epoxy asphalt paint or 1751 semi-hard rubber lining, and the pipe part is lined with plastic;

• The equipment is equipped with local sampling device and inlet and outlet pressure gauge; All joint flanges are rated PN1.0.

Principle Of Multi-Medium Filter

 

Inside the MMF is filter material such as quartz sand and anthracite which are different in size so their placement is arranged from top to bottom order and small to large order. The surface of filter material will retain some pollutants when water follows through from top because of adoption and mechanical resistance. At the same time, these suspended substances are overlapped and bridged, as if a thin film is formed on the surface of the filter layer, which continues to filter the suspended substances in the water, thus forming the so-called membrane filtration.

Multi - medium filtration not only has the function of membrane filtration, but also has the function of infiltration filtration. This interception occurs even when water enters the intermediate filter. the suspended particles in the water flowing through the filter layer, have more opportunities to contact each other, the suspended material in the water on the surface of the particles that filter material with flocculation body attached to each other, so as to contact coagulation process.

The multi-media filter adopts parallel operation mode and sequential backwash. When running in parallel, the filter velocity can be greatly reduced, and the lower filter velocity can improve the filtering effect.In parallel operation, the bacteria reproduction of the standby filter can be prevented to the maximum extent, which is conducive to the long-term stable operation of the ultrafiltration device.

In order to prevent small particle impurities from entering deeper filter sand and penetrating the filter layer after the backwash use, the filter layer height is increased appropriately. The MMF adopts refined quartz sand and anthracite with uniform particle size to achieve perfect process effect. 

Backwash Of Filter

When the pressure difference of the filter reaches the set value, or when the water quantity is reached, the automatic control system will backwash the filter in order to restore the filter performance. The backwash water of the filter is reverse osmosis concentrated water, and the raw water supplement pipeline is provided.Backwash water is supplied by the backwash pump.The backwash pump is used and prepared. In order to prevent the backwash pump from having a relatively large impact when backwashing, an electric slow door is set at the outlet of the backwash pump.Other instrument configurations include a backwash flowmeter and a backwash outlet pressure gauge.

The inlet of the backwash water tank is equipped with a hydraulic remote control ball float valve that is interlocked with the water tank level, and automatically adjusts the ball float valve as the water tank level changes to maintain the water tank level at the set value.The signal of water tank level can be displayed centrally on the upper computer. The water tank is filled with concentrated water of reverse osmosis, and the raw water supplement pipeline is provided.
 

Multi - Medium Filter Processing And Other Configuration

The rubber plate used in the equipment lining is semi-hard rubber. The rubber layer is extended to the external flange joint surface and is vulcanized by the vulcanizing tank.

The internal pipeline is connected with the body by flange, which is convenient for maintenance and replacement of components. The material of the internal parts shall meet the specified requirements, and the fasteners shall be the same as the material of the internal pipe fittings.

Internal parts are fixed and reinforced to withstand the impact of water flow.

The material of the equipment endoscope is transparent, corrosion resistant and thick enough to withstand the design pressure of the vessel and the test pressure at the time of testing. The inner surface of the endoscope is flush with the inner surface of the container. Sight mirror symmetry setting. Lighting feet are provided.

Equipment for program control, automatic operation, but also to retain the field manual operation conditions.

The water and air distribution inside the equipment is uniform, without bias, and has sufficient strength. The inner surface of the manhole and the manhole cover shall be flush with the inner surface of the container. The manhole is equipped with a complete set of components such as manhole cover, washer, bolts, nuts and lifting boom.