Prominent Gravity Filters

Prominent Gravity Filters

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Filtration capacity 6.5 – 62.0 m3/h

The gravity filter INTERFILT® SK is an open sand filter system for extremely economical water treatment. The filter system operates with differential pressure-controlled backwashing and an integral backwashing water tank.

Economical water treatment with gravity filters - using the gravity of the water alone.

The automatic gravity filter uses the principle of differential pressure and essentially consists of the cylindrical tank, its fittings, the automatic backwashing system with injector, the raw water feed and baffle tube, filter nozzles and filter filling unit

Your benefits

  • No controls: The filter needs no moving parts, like valves, flow meter, controller or display equipment, for filtering/backwashing and post-rinsing
  • No pumps: The required volume of backwashing water is stored in the storage tank below the filter, making a back-flushing pump redundant.
  • No compressed air, pressurised water and electrical energy: The filter controls and performs all processes independently
  • No operating personnel: The filter works fully automatically, without external intervention
  • No wearing parts: No moving parts – no wear and tear.

Field of application

  • Cooling water, partial flow filtration
  • River water, process water and potable water treatment
  • Removal of iron from well water
  • Waste water cleaning to reduce the content of suspended matter, CSB, BSB5 and phosphate (4th cleaning stage)(Sand) Filtration for Potable Water
  • Technical Details

    • Material: Polyethylene PE-HD
    • Filter material: Filter sand DIN EN 12904, other filter materials on request

    The filter essentially consists of:

    • Cylindrical tank
    • Fittings
    • Automatic backwashing system with injector
    • Raw water feed and baffle tank
    • Filter nozzles and
    • Filter filling unit

    Optional additional equipment:

    • Cover for cylindrical tank
    • Frost protection insulation with supplementary electric heating
    • Combined air/water backwashing
    • PE-HD backwashing water sump tank
    • Other options on request

    Type List and Capacity Data

    Type Filter diameter Filter capacity Back wash Water Weight empty Weight in operation
    mm m3/h ∼ m3 ∼ t ∼ t
    SK- 9 900 6.5 1.4 1.2 4.5
    SK- 12 1,200 11.5 2.5 1.5 7.1
    SK- 15 1,500 18.0 4.5 1.9 10.5
    SK- 18 1,800 26.0 5.5 2.3 15.0
    SK- 21 2,100 35.0 8.5 2.8 19.5
    SK- 24 2,400 46.0 10.0 3.0 25.0
    SK- 28 2,800 62.0 14.0 3.5 30.0
    Flow rate: 3 … 10 m/h
    Backwash intervals:
    (depending on type and amount of pollutants)
    Approx. 8 … 36 h
    Head loss: 120 … 150 mbar
    Clean water solids figure:
    (depending on raw water and filter material)
    0 … 3 mg/l
    Backwash flow rate::  
    At the start 44 m/h
    In the middle 37 m/h
    At the end 30 m/h
    Cylinder height:
    (same for all types)
    4,500 mm
    Overall height:
    Depending on filter diameter
    6,500 mm
    Backwash and refilling time: 13 … 15 min.
    Filter sand in accordance with EN 12904  
    – Height of bed 600 mm
    – Grain size range 0.71 … 1.25 mm
    Filter nozzles:  
    – Type Lamellar nozzle
    – Material PPN
    – Slot width 0.2 mm

    As system components are produced individually according to application, we will inform you of prices on request.

    We reserve the right to change components and their construction, as long as these do not affect their performance or function.