Parason Disc Filter (PDF)

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Disc Filter is an optimized solution from Parason to enhance the capacity and filtrate quality by reducing freshwater consumption, save heat energy by closing the water circuit of the dewatering process. All Parason and conventional disc filters can be upgraded to these new high-quality products

The new generation of dewatering from Parason

Parason’s continuous R&D activities emphasize supporting customers by offering higher capacities as well as higher energy efficiency equipment to get sustainable production. We are dedicated to finding tailor-made solutions to fit customer’s process requirements. You can rely on our world-class manufacturing facility and fully equipped R&D department with highly qualified experts to provide you latest technology.

Efficient and low-cost dewatering

To ensure efficient dewatering capacity, Parason has developed a Parason disc filter offering superior filtrate qualities by reducing freshwater consumption. As a result operating costs, freshwater consumption and fiber loss can be reduced. The load on the ETP/WTP is reduced drastically

Working Principle:

We have developed Parason Disc Filter with a focus on three key issues:

  • Process solutions
  • Thickening and fiber recovery
  • Mechanical strengths
  • Environmental impact
  • Deaeration
  • Reduced ETP load

Principle Operation

The pulp mat starts to form under gravity, ensuring optimum dewatering characteristics. As the filtrate channel passes a bridge in the filtrate valve, the filtrate is diverted to the clear filtrate outlet which is connected to the barometric leg. For fiber recovery, the filtrate is diverted to clear filtrate and super clear filtrate outlet. The line of sectors emerging from the suspension is drained and the pulp mat is dewatered. A bridge in the valve shuts off the channel from the vacuum. Water or air jets strip the pulp mat from the sectors on the rising side of the discs. The filter cloth is cleaned by oscillating showers.


By optimizing the deaeration of the inlet flow between each disc, the air content in the pulp suspension is kept to a minimum.

By reducing the internal volumes of the disc sectors to the optimum, they drain quickly during the drying of the pulp mat, which allows higher rpm of the disc.

By the new unique design of the filtrate valve with separate removal, a high and stable vacuum is achieved.

Filtrate Quality

By optimizing the distribution of the inlet pulp flow along the whole length of the disc filter with a stationary baffle, ensures uniform pulp consistency.


With smaller internal volumes in the disc sectors, a smaller volume to unclear filtrate is carried over from the cloudy filtrate to the clear filtrate. By designing each center shaft flow channel according to the application and current flow, it is possible to create the best process results with good filtrate clarity.

Outlet consistency

As the internal volumes of the pulp disc sectors are smaller, they empty quickly when they leave the suspension, and drying of the pulp mat is carried out while gives a longer thickening time.

By this new unique design of the filtrate valve, with separate air removal, a high and stable vacuum is achieved.

Outlet consistency 8-12% depending on applications.

Centre Shaft

By the new unique design of the center shaft with full visibility during welding of the internal flow channels, the center shaft is welded in a safe it is extremely strong and can stand for high mechanical forces. This design gives a long lifetime of the center shaft.

Special Application:

Pulp Thickening

To get outlet consistency of 8-12% with clear and cloudy filtrates.

Fiber Recovery

For handling paper machine backwater and recovering valuable fibers, with excellent quality of cloudy, clear, and super clear filtrates

Broke System

For thickening application of Broke in large mills.


Expertise in rebuilding and refurbishing disc filters of other manufactures.

Process Parameters

  • Inlet consistency 0.7 to 1.1%
  • Outlet consistency 8 to 12%


  • Newsprint
  • Writing and Printing paper
  • Kraft
  • Duplex Board


Ranging from 40 to 400 TPD



Looking at the throughput of equipment which is directly proportional to the area of filtrate, Parason offers the same size disc filter sector with more filtrate area due to the wave design of the segment. More filtrate area gives more throughput with minimum maintenance and running cost.

New design of PDF segment for Excellent stability and higher capacity

Benefits with Wave PDF segment
  • Minimum Maintenance and running costs
  • Higher service life of the PDF segment
  • Superior filtrate quality
  • Reduction of freshwater consumption due to the close water circuit
  • No need for filter bags replacement it is called as bagless PDF


Parason Disc Filter also offers the Bump segment. The integration of the segment bag with bump design offers the additional suction area and uniform mat formation. This extends the life and reduces the maintenance cost.

Excellent running time due to efficient bump segment design

Benefits with Bump Segment
  • Undisturbed uniform mat formation
  • Faster knock-off and better cleaning due to point contact
  • Reduced maintenance cost
  • Solution for any make or model
  • Due to the unique design of the bump, the water gets drained downwards without damaging opposite mat formation


There are two options available for discharge of thickened pulp


  • Repulper gives uniform transportation when consistency is high
  • Thickened pulp can be directly fed to disperser unit
  • Direction of pulp feed can be changed as per requirement


  • Only Hopper can be provided if capacity of PDF is not too big
  • Thickened pulp can be directly drop into chest
  • Less maintenance is required as there are no wear and moving parts
  • No power is required as pulp is dropped in chest by gravity
  • Reduced cost as compared to repulper option

Right option can be selected as per location and process requirement. Please consult Parason experts to get the right option in your mill. Parason continuously works on various options to suit the customer requirement.

Parason disc filter service solutions

Benefit from tailor-made products and services as a result of process knowledge at first hand

Thickening Series 3.7

Product Type No of Discs A[m] B[m] C[m]
PDF-3.7 X 04 4 4.00 4.77 4.97
PDF-3.7 X 08 8 5.20 4.77 4.97
PDF-3.7 X 10 10 5.80 4.77 4.97
PDF-3.7 X 12 12 6.40 4.77 4.97
PDF-3.7 X 16 16 7.60 4.77 4.97

Thickening Series 5.2

Product Type No of Discs A[m] B[m] C[m]
PDF-5.2 X 04 4 4.30 6.67 6.8
PDF-5.2 X 08 8 5.60 6.67 6.8
PDF-5.2 X 12 12 6.90 6.67 6.8
PDF-5.2 X 14 14 7.55 6.67 6.8
PDF-5.2 X 16 16 8.20 6.67 6.8


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