The Continuous Flow Sand Filter is a high-efficiency dynamic filtration system developed by our company, utilizing the countercurrent continuous cleaning principle. This innovative solution overcomes the limitations of traditional intermittent operation by enabling simultaneous filtration and cleaning processes. Designed to effectively remove suspended solids, turbidity, and colloidal substances from water, it provides a highly automated, uninterrupted, and space-efficient filtration system. Particularly suitable for applications requiring continuous and stable water supply, this system delivers reliable performance in demanding environments.
- Structure and Working Principle
- Core structural composition
The device typically features a vertical cylindrical structure, with its core system integrated from top to bottom.
- The upper filter zone serves as the primary working area, with fine quartz sand as the filtration medium, forming a vertically moving filter bed.
- The sand washing unit (core component): The air sand lift (or pump system) at the center of the filter, along with its matching sand washer, is the key to ensuring continuous operation.
- Water distribution and collection system:
- Inlet distributor: Located at the top of the filter bed to ensure uniform distribution of the water to be filtered.
- Bottom water collector: Located at the bottom of the equipment, it collects filtered water.
- The drive and control system includes air compressor (for air lifting), drive pump, control system and monitoring instrument.
- Working Principle
The operation of the equipment is based on the dynamic balance principle of "the sand filter material moving from top to bottom, and the sewage flowing from bottom to top in reverse flow".
- Continuous filtration: The water to be filtered enters from the top and moves downward through the slowly moving sand filter layer, where impurities are retained. The clean water is collected and discharged by the bottom water collection system.
- Continuous cleaning: The contaminated filter sand with impurities settles to the conical base under gravity, then is continuously and stably conveyed by an air sand lift to the top sand washer.
- Efficient cleaning: Inside the sand washer, the filter sand undergoes intense friction and counter-current flushing with a small amount of cleaning water (approximately 2-5% of the total water volume). The contaminants are separated and flushed away, while the clean sand returns to the top of the filter bed by gravity, forming a closed-loop cycle of "filtration, contaminant removal, cleaning, and recirculation".
- Core Technical Features
- Continuous operation ensures stable water supply: The filtration and cleaning processes run 24/7 in sync, eliminating the need for periodic shutdowns like traditional filters. This fundamentally prevents water supply interruptions or fluctuations caused by backwashing, delivering consistent water quality and flow.
- Efficient cleaning with stable effluent quality: The system employs countercurrent air-lift or pump-lift sand washing, delivering superior cleaning performance. This ensures sustained cleanliness and filtration efficiency of the sand, ultimately yielding consistently low-turbidity effluent.
- Fully automated operation with simplified management: The entire sand circulation and cleaning process is automatically controlled by a program, requiring only monitoring of operational parameters. This enables near-unmanned operation, significantly reducing operational workload and labor costs.
- Compact design with minimal footprint: By eliminating the need for backwash backup equipment and utilizing high-efficiency dynamic filtration, this system typically requires less space and volume than conventional sand filters while maintaining equivalent processing capacity.
- The operation energy consumption and water consumption are low: the cleaning process only requires a small proportion of water to be treated, and the energy consumption of sand lifting is concentrated, so the energy consumption and water consumption per unit of water produced may have a relative advantage.
- Main technical parameters (for reference)
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Parameter item
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Description / Reference Range
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per unit processing capacity
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Standard series: 20 – 400 m³/h (multiple units can be connected in parallel or customized for larger capacity)
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design filtration rate
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10 – 15 m/h (or higher, depending on the design)
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Filter material (quartz sand)
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Effective particle size: 0.8 – 1.2 mm; Filter bed height: 1.5 – 2.5 m
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outflow turbidity control target
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The design generally stabilizes at ≤ 1– 3 NTU
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sand washing water quantity
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accounting for approximately 2% to 5% of the total water treatment volume
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working pressure
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Operating at atmospheric or low pressure (typically ≤ 0.1 MPa gauge pressure)
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navar
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PLC-based automatic control with monitoring of filtration rate, pressure differential, and sand circulation status
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Main material
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Carbon steel anti-corrosion (rubber lining/spray coating), stainless steel (SS304/316L)
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- Typical Application Fields
This filter is particularly suitable for scenarios requiring 24/7 continuous, stable filtration with high automation demands.
- Municipal sewage advanced treatment and reuse: As the core filtration unit of tertiary treatment, it ensures the stable compliance of reclaimed water with standards.
- Industrial circulating cooling water system: As an efficient bypass filtration device, it continuously removes suspended solids and controls turbidity.
- Industrial wastewater treatment: Precision filtration for wastewater treatment in industries such as papermaking, chemical, and food processing.
- Seawater desalination pretreatment: serves as a security filtration system before reverse osmosis membranes, providing continuous protection for the membrane system.
- Water treatment: Suitable for filtration process upgrades in medium and small-scale water plants to enhance production capacity and stability.
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