Quartz Sand Filter

A quartz sand filter is a deep-bed filtration device that uses quartz sand as the filtering medium. By forming a uniform, multi-layer structure with sands of similar particle sizes, it effectively removes suspended solids, organic matter, and inorganic impurities from water.

Its core working principle is physical interception, making it suitable for treating water with organic content above 10 mg/L. It is especially ideal as a primary filtration unit.

II. Structural Components

1. Filter Tank

   • Typically made of metal (carbon steel or stainless steel) with a surface coating of powder or baked paint to prevent rust and corrosion, suitable for long-term outdoor use.

   • Tank diameters range from 0.35 to 1.2 meters, with an internal sand bed thickness of 25–50 cm and a bottom drain port.

2. Filter Media

   • Quartz sand with a particle size of 0.4–1.2 mm, layered by coarse, medium, and fine grades to enhance filtration precision and efficiency.

3. Automatic Backwash System

   • Includes differential pressure sensors, a PLC controller, and three-way hydraulic control valves. Backwashing can be triggered either by a timer or when the pressure difference reaches a threshold (typically ≥0.07 MPa).

4. Auxiliary Components

   • Inlet/outlet ports (flanged or quick-connect), water distributors, collectors, and optional compressed air injection devices to enhance backwashing performance.

III. Operating Process

1. Normal Filtration

   • Raw water enters from the top and passes through the sand bed. Impurities are trapped on the surface and within the sand, while clean water exits from the bottom.

2. Backwash Process

   • Trigger Conditions: Initiated by either pressure differential exceeding the threshold or pre-set timer.

   • Cleaning Method: The inlet valve closes, and filtered water from other units is used to backwash the sand bed in reverse, flushing out contaminants through the drain port.

   • Enhanced Cleaning: Some systems inject compressed air to improve cleaning efficiency through air-water mixing.

IV. Technical Features

1. High Filtration Efficiency

   • Suitable for high-turbidity water; can reduce suspended solids to 5–10 mg/L. Ideal for agricultural irrigation and industrial circulating water pretreatment.

2. Automated Operation

   • Supports unattended operation; filtration can continue during backwash cycles, making it suitable for continuous production environments.

3. Modular Design

   • Multiple tanks can operate in parallel to increase capacity. Can be combined with mesh or disc filters for enhanced performance.

4. Corrosion Resistance and Durability

   • Both the tank and filter media are corrosion-resistant and long-lasting, well-suited for complex water conditions.