Rubber and Plastic Production

Terraced Filters

The Dahlman Terraced Filter has found its roots in the filtration of gel particles in the production process of Vinyl Chloride Resin (PVC), Polyol and Rubber. Originally a conical pleated type of filter element design with 2,5 m2 filtration area was used which used a resin bonded sealing. 

The new generation has led to an element which has a sewn construction instead of resin bonded and a filter surface area of 5,4 m2 (more than two times than its precursor). 

The name Terraced Filter, abbreviated T-Filter, derives its name of the radial pleated construction of the filter media. The filtration direction is from inside to the outside. Between each terrace drainage material is foreseen to provide some space between each layer. This ensures a proper flow distribution  and makes a high DHC possible. 

The latest development is doubling the length of the element. It still has the same diameter as the standard filter, but by increasing the length it has now a filter surface area of 9,5 m2. Typically this double length element is used for excessive dirt loadings. 

The Terraced Filters are available with 1, 3, 5, and maximum 7 elements installed with single or double length elements, depending on the flow rate, dirt load and requested overall system pressure drop. 


Advantages Dahlman Terraced Filters:

  • Large filter area per element, surface and depth filtration combined in one element,
    which offers;

                - Filter area 5,4 m2 up to 9,5 m2 per single element

                - Very high dirt holding capacity (DHC), up to 35 kgs per element, therefor low element consumption

                - Significant reduction of operation involvement for change outs

                - Depth filtration combined with a large surface

  • Very easy change out;

               -  Quick sealing system design allows for super fast change out time

                - No risk of bypasses; sealing material is filter fabric

  • No more environmental pollution;

                 - The filter is completely drainable. The element can be drained using suitable gas e.g N2 / air or steam       

                    before replacement; product loss reduced to a minimum

                - No more operator exposure to the pollution, solids captured inside the element, which results in a                                                  

                   minimum contact between the product and the operator

                - Elements are incinerable, the element is supported by a metal basket, therefore only the filter media                  

                   is waste

  • Elements available in various micron ratings, materials and efficiencies, depending on the requested chemical resistance;

                 - Materials: Polyamide / Polypropylene / Ryton / Nylon / PTFE

                 - Micron ratings: 1 / 5/ 10 / 25 / 50 / 100 / 200


 Proven performance In the following applications:

  • SAN-polymer polyols
  • Polymers
  • Polyols
  • Rubber dissolutions
  • Vinyl Chloride Resin