BHS Filtration


General Description

The BHS Autopress uses filter press technology with the extra benefit of complete containment and automatic cake discharge.  It is an alternative to centrifuges, nutsche filter-dryers and filter presses.

The Autopress provides for reproducible cake thickness which provides for validated and GMP process operation.  The cake can be filtered, washed in the forward and reverse directions as well as dried in the forward and reverse directions. 

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The Autopress technology consists of circular filter plates that are sealed in a movable housing. The filter plate design allows for forward and reverse flow operations and can be automatically cleaned to less than 1 ppm residual cross contamination.  Automatic and contained discharge is via scraper knives.  PLC control is via Batch S-88 standards.


Technical Description

The horizontal filter plate stack consists of circular plates and flexible spacers for absolute plate-to-plate sealing.

The filtration housing forms a pressure-tight enclosure around the plate stack via a flexible membrane that is pressurized 1 – 2 bar over the operating process pressure. 

For cake discharge, the housing opens, the plate stack relaxes and scraper knives remove the cake from each plate in a sequential manner. 

Clean-In-Place (CIP) is via spray nozzles and spray bars to meet all riboflavin tests.


The suspension is pumped under pressure into the gaps between the plates. Filtrates discharge to atmosphere. Filter cakes build up on both plates and grow towards each other, completely filling the gap.

Filter cake washing

Once the cakes are formed, they are washed; starting from one side to the opposite side. When the washing process has been completed, the cake can be dried by vacuum or by compressed gas.   Cake pressing is also possible.

Filter cake drying

In a similar way to the cake washing process, the cake can also be blown dry from the filtrate and suspension side.

Filter cake discharge

For cake discharge, the housing opens, the plate stack relaxes and scraper knives remove the cake from each plate in a sequential manner.

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The main fields of applications are:

  • Specialty Chemicals 
  • Food 
  • Pharmaceutical

In general:

The Autopress is able to meet the following demands:

  • Filtration suspensions containing solvents
  • Filtration of poor to average filtering suspensions
  • Filter cake thickness from 5-20 mm
  • Use of pressure filtration up to 10 bar
  • Temperatures up to 200 °C
  • Filter cake drying
  • CIP and sterilizing operations as all parts are free-draining 
  • Toxic and highly flammable products

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Technical Data

type AP 300 AP 500 AP 700 AP 1000
Filter area in m2 0.2 - 1.0 1.0 - 5.0 2.0 - 12.0 4.0 - 24.0
number of intermediate plates 1 - 9 2 - 14 2 - 17 2 - 17
plate diameter in mm 300 500 700 1000

Materials of construction

  • Filter plates in stainless steel and synthetic materials 
  • Filter media in stainless steel and synthetic materials 
  • Membrane and spacer in EPDM, PTFE, Viton and similar materials

Technical data may change due to technical progress. Subject to modification without notice.

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