Data Sheet

Technical Specifications

  • Frame in AISI 304/316 stainless steel, depending on requirements
  • Shaftless spiral in high tensile carbon steel or AISI 304/316, depending on requirements
  • Tank designed to increase the settling effect and prevent the risk of jamming
  • The base of the tank is equipped with wear bars made of stainless steel on which the screw rests. The construction system allows for easy replacement
  • Flow rate: up to 100 m³/h
  • Separation: >= 90% of particles sized >= 0.2 mm (at nominal flow rate)
  • Organic matter contents of solids at discharge: <= 3%
  • Grit discharge chute
  •  Extracted grit bagging unit: in single bags or continuous liner
  •  The machine can be made of stainless steel of the required type
  •  Air blower
  • Municipal treatment plants for separation, washing and dewatering of grit deriving from the grit separation process
  • Industrial plants with the requirement to separate, wash and dewater grit
  • A single machine for grit separation and washing
  •  The washed grit can be recycled
  •  Shaftless spiral
  •  No supports
  •  Reduced rotation speed
  •  Reduced installation cost


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Spare Parts

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Description and operation

Definitive Ecology’s GW grit classifier with washing stage separates/classifies and washes grit to remove the organic matter that it always contains. The grit slurry is transferred to a helical chamber which imparts rotary motion to the particles: the water changes direction of rotation as it enters the tank. Due to the increase in volume, the effluent undergoes a significant velocity reduction in the tank. The combination of these two factors allows the heavier particles to settle so that they form a bed at the bottom of the tank, while the lighter particles remain in suspension. Water is injected into the bottom of the tank to provide counter-current washing of the grit bed: the lighter particles are ejected with the cleared water or through a valve located on the tank. The washed grit reaches the pit supplying the lifting screw conveyor. Before reaching the outlet, the extracted grit is dewatered. An arm rotating at reduced speed in the tank optimises separation of organic matter from the grit. In the case of high organic matter contents the tank may be equipped with an aeration system in which air is injected through dedicated nozzles.

Models available

  • GW = grit classifier with washing