API , Chemical and Pharmaceutical manufacturing use Activated carbon. Specific activated carbons provide superior removal of colour compounds, odour compounds, proteins and other contaminants that could be present in the raw materials, or that form during production.  Removal of these carbon particles from final product is a daily chore at these facilities.  Contufilt –WW or M is an outside-in candle filtration process  for polishing and removing activated carbon  from slurries. The systems are back washable and easy to use and maintain. The mechanism uses pre-coat with WW hexagonal screens as support.


  • Activated Carbon filtration
  • Slurry Filtration

Feature and Advantages

  • Totally Closed System
  • No manual Handling
  • Defined Micron Retention with Cake
  • Easily Backwashable
  • No Bypass
  • Zero Product Holdup
  • Small System sizing
  • Low Downtime




Process Operation
The system consists of a number of equally sized pressure vessels each containing an equal area of WW hexagonal screens tubes or Laminates are arranged in triangular pitch or distance suitable for applications. The vessel performs the specific functions of filtration, in-situ reverse flow, gas assisted discharge of collected dirty pre-coats  and when required, an in-situ soak to re-slurry the pre-coat / solid cakes if required.

The mechanism of filtration is a direct interception of pre-coat solutions  on the surface of the WW Hexagonal screens tubes. This initial capture starts and enhances the capture of all other particles building a pre-coat cake. The principle of filtration is Cake formation.  Sometimes to assist the filtration in difficult to filter masses a body feed with the necessary grades of keisulguhr, perlites, Filter-cel are used and then the  ongoing formation of a surface cake continues to build- up to a depth of 10 mm or greater depending on the cake resistance and characteristic. Complete recovery of liquids is achieved and the particles are purged out of the system without having to open the system.

At the end of each filter cycle, solids are backwashed off the inside of the elements and discharged as a concentrated slurry or wet cake.  The system offers ultimate particle retention, back-washability, solids capacity and strength. These systems can be used in conjunction with filter aids for difficult filtration applications.

The WW Candles or Laminates  have a open profile and are easy to be backwashed. The backwash filter system is used in slurry de-colorisation using activated carbon polishing filtration in syrups and solutions for improved product quality and reduced operating costs.

Technical Specifications

  • Closed system: Helps reduce operator exposure to hazardous materials
  • Accessibility: Easy access to elements from top
  • Compact Design: Element bundle is removable as an assembly
  • Coded Vessels: Filter areas up to 200 m2, withstands differential pressure as high as 10-15 Kg/cm2. Designed generally in accordance with ASME section VIII.

The housing are  designed for:

  • the specified pressure at the temperature given in the technical specifications
  • even flow distribution,
  • specified element spacing for cake build up, and
  • easy access for change-out