First,Shallow sand filter
A shallow sand filter is a media filtration system consisting of one or more standard high-speed filter units. The water flows through the internal water distributor and water collector, and uses different media to remove particulate matter and reduce turbidity. If a specific filter material is installed, such as activated carbon, anthracite, etc, the corresponding organic matter, ions, etc. can also be adsorbed and removed.
Shallow sand filters are available in various specifications, with filter units ranging from 16 inches (400mm) to 96 inches (mm), and can be installed in different ways. The shallow sand filter can be used as an independent filtration system, using the water supply pump in the existing process. If it is used as a side filter, it can also be equipped with its own pump. It is also possible to install multiple processing units on a common pipeline.
The cleaning methods of the shallow sand filter are manual, semi-automatic and fully automatic, which are activated by manual button, PLC, pressure difference or management system respectively. The backwash cycle and backwash time are adjustable, and the factory setting is 3 minutes. This control is realized by DLFCS automatic control system. Users can also choose PLC control system, which can realize high-demand control such as centralized or remote communication.
Second,the filtration principle of shallow sand filter
When the system is in the filtering state, the pressurized water flows into the water distribution system from the inlet of the filter unit, and reaches the filter material layer evenly. When the water flows through the filter material layer, the suspended matter is intercepted by the filter material. There is a water collector with precise slits at the bottom of the filter, and the filtered clean water is evenly collected and flows out of the filter.
With the continuous accumulation of impurities in the filter material layer, the pressure loss continues to increase. When the pressure difference increases to a certain set value or reaches the set cleaning time, the system will automatically switch to the backwashing state. The pressurized water enters the filter material layer through the water collection device, flushes it, and makes the trapped pollutants fall off and discharge the filter system. The backwash lasts for at least two minutes, and the valve automatically switches the system to filter state.
Third,Features and advantages of shallow sand filter
1. High filtration speed and low pressure loss, to solve the problem of slow filtration speed and small flow of ordinary mechanism media filters.
2. Modular setting, small footprint, less piping, and low investment. The floor space is reduced by more than 40%, and the amount of piping works is reduced by more than 50%.
3. Manual, semi-automatic and fully automatic backwashing is optional. The backwashing water source can be selected from the system, water tower or external water source, and can be automatically switched.
4. 16-inch-96-inch units can be selected from various models, and multiple units can be combined, and the processing flow can be expanded arbitrarily.
5. The shell and pipes are made of carbon steel Q235B with phosphate surface treatment, electrostatic spraying and baking at a high temperature of 240 degrees, which is extremely corrosion-resistant. Also available in stainless steel.
Fourth,the scope of use of shallow sand filters
1. Industrial process water filtration---such as water protection filtration for nozzles and heat exchange stations.
2. Industrial circulating water filtration---steel, metallurgy, papermaking, heat exchanger, electric power, petrochemical, food, air conditioning system and other industries.
3. Raw water treatment and filtration---surface water, river water, river water, lake water, sea water, etc.
4. Irrigation filtration---water filtration for farmland, parks, municipalities and golf courses.
5. Water filtration in industries such as aquaculture, swimming and water parks.
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