The BHS Autopress operates as a filter press technology with the benefit of complete containment and automatic cake discharge. It is an alternative to centrifuges and nutsche filter-dryers.

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.

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.

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 BHS Candle Filter provides for thin-cake pressure filtration, cake washing, drying, reslurry and automatic discharge as well as heel filtration in an enclosed, pressure vessel. Units are available from 0.17 m2 up to over 100m2 of filter area per vessel.

Candle Filters are installed for clarification and recovery applications from liquids with low solids content with 5% to less than 1% solids and trace amounts.

Technical Description

The filter candles, consist of three components: single-piece dip pipe for filtrates and gas, perforated core with outer support tie rods and filter sock media. The filtrate pipe is the full length of the candle and ensures high liquid flow as well as maximum distribution of the gas during cake discharge. The perforated core can be a synthetic material, stainless steel or Hastelloy and is designed for the full pressure of the vessel. The outer support tie rods provide for an annular space between the media and the core for a low pressure drop operation and efficient gas expansion of the filter media sock for cake discharge. Finally, the filter media is a synthetic type with a clean removal efficiency to less than 0.5 microns. As the cake builds up, removal efficiencies improve to less than 1 um.

The BHS Pressure Plate Filter provides for thin-cake pressure filtration, cake washing, drying, reslurry and automatic discharge as well as heel filtration in an enclosed, pressure vessel. Units are available from 0.17 m2 up to over 45 m2 of filter area per vessel.

Pressure Plate Filters are installed for clarification and recovery applications from liquids with low solids content with 5% to less than 1% solids and trace amounts.

Technical Description

A filter cake is filtered onto a set of horizontal, slightly conical filter plates – arranged in a stack inside a pressure vessel. The filtrate passes through the filter media to a central manifold from where it leaves the pressure vessel. Following the process steps of filtration, washing, extraction, steaming, blowout or hot drying, the filter cake is vibrated from the set of plates by two unbalanced motors.

General Description

The BHS Rotary Pressure Filter is a continuously operating unit for pressure filtration, cake washing and drying for slurries up to 50% solids."

Filtration is conducted via pressure of up to 90 psig. Positive displacement washing, reflux or counter-current washing follows filtration. Multiple washing steps as well as solvent exchanges, steaming and extraction can also be accomplished. Finally, the cake is dried by blowing hot or ambient-temperature gas through the cake.

The Filter has a uniquely designed discharge system, which provides for atmospheric discharge from pressure filtration. After automatic cake discharge, the filter cloth is washed; the clean filter cloth the re-enters the feeding / filtration zone thereby continuing the process. All solvent and gas streams can be recovered separately and reused in the process to minimize their consumption.
The BHS-Rotary Pressure Filter works on the principle of cake filtration and is designed for the following operating parameters:

• Pressure design up to 6 bar
• Cake thickness up to 185 mm
• Operating temperatures up to 200°C
• Filtration capacity from several kilograms/hour to
• over 85 tons/hour of dry solids
• Solids content up to 50% and higher by weight
• Particle size distribution from 1 – 2 microns to over 200 microns