Crossflow Grit Detritor & Rake Classifier

Crossflow Grit Detritor

Influent first enters the collection tank through baffles to slow down the flow and assist grit settlement. The tank is capable of handling a wide range of flow variation.

A rotary scraping mechanism, driven from the centre of the tank, moves settled grit through a discharge point located at the side of the collection tank.

From here the grit is discharged to a grit classifier system by means of gravity or by pumping.

The Tuke & Bell Crossflow Grit Detritor incorporates the following features: –

  • Robust structure designed to resist imparted grit loads.
  • Heavy duty slewing ring carries entire scraper load – zero additional load on gearbox bearings.
  • All bearings and drives rated for 100,000-hour design life.
  • Direct coupled drive removing maintenance intensive gear drives.
  • Simply decoupled drive facilitating easy drive removal.
  • Lubrication points for slewing ring easily accessible from walkway.
  • Various scraper configurations available – No. of arms and No. of scrapes per revolution are possible design variables.
  • Scraper blades feature replaceable wear tips that can be inverted for addition life.
  • Scraper blade wear tips are height adjustable to account for tank irregularities.


Rake Classifier

The Tuke & Bell Rake Classifier is a multiple-rake reciprocating mechanism, mounted within a cleaning channel, which is a narrow, continuously sloping ramp.

The reciprocating action moves the grit, up the ramp towards a discharge point above top water level. At this point the grit is free of water, which assists easy and efficient disposal, and free of organic matter caused by the washing action of the reciprocating rakes.

A pumping unit is located within the organics return chamber which induces a current of liquid to flow from the collecting tank through the cleaning channel and back into the collecting tank.  For free-standing Rake Classifier units, a wash water pipe connection is included for cleaning of the grit.

Organic matter originally settled with the grit and freed during the washing process is diverted back to the sewage flow for further treatment.

The Tuke & Bell Rake Classifier incorporates the following features: –

  • Lightweight space frame design to reduce drive loads.
  • Single sided crank allows for simple drive removal.
  • All pivot bearings are 100% maintenance free – No lubrication required.
  • Heavy duty, replaceable ‘Big end’ crank bearing lubricated by single point grease canister or local grease line.
  • Fully enclosed mesh panel guards allow instant inspection of the rake.  Drive is accessible through full size, locked double doors.
  • 25-year design life.
  • Typically, the Rake Classifier is used in conjunction with a Crossflow type Grit Detritor and together carries out the complete grit extraction process within a compact area. The system can be located either above or below ground level. The Rake Classifier is available as a design suitable for a civil or steel chamber construction.