Cake Filtration Principle

Slurry pumps into pressurized vessel containing filter media. Pressure forces liquid through media while solids accumulate forming cake layer. Cake itself becomes filtration medium capturing finer particles. Growing cake increases resistance until reaching thickness limit requiring discharge cycle.

System Design

Pressure vessel with filter element assembly, slurry inlet distribution, filtrate collection manifold, cake discharge mechanism, compressed gas for blow-down, wash liquid injection, and automated controls managing cycle. Complete integrated system from feed to solids discharge.

Operating Pressure

Typical 50-150 psig overcomes cake resistance maintaining flow rate. Higher pressure enables thicker cakes or lower permeability solids. Pressure selection balances throughput versus cake compaction affecting moisture content and discharge properties.

Cake Formation

Initial filtration rapid as liquid passes through clean media. Rate decreases as cake builds adding resistance. Filter cycle continues until target cake thickness, pressure drop limit, or time expires. Proper cycle termination optimizes productivity.

Filter Media

Woven cloth captures solids forming cake. Metal mesh provides support. Precoat materials like cellulose improve fine particle retention. Media selection considers particle size, chemical compatibility, cake release, and filtrate clarity requirements.

Cake Discharge

Gas blow-down compresses and dries cake. Mechanical scrapers or vibration assist release. Some designs use backwash dislodging cake. Discharged solids drop to vessel bottom for removal. Dry cake easier handling than wet sludge.

Washing Capability

Wash liquid displaces mother liquor from cake reducing product losses or impurities. Multiple washes achieve target purity. Wash efficiency depends on cake permeability and displacement thoroughness. Critical for product recovery applications.

Applications

Pharmaceutical API isolation with product washing, chemical catalyst recovery, wastewater biosolids dewatering, mining concentrate filtration, food processing clarification, and any process requiring batch pressure filtration with cake formation.

Material Construction

Stainless steel 316 for pharmaceutical and food applications meeting cGMP requirements. Hastelloy or exotic alloys for corrosive services. Carbon steel for mild applications. Sanitary polished finishes where required.

Automated Control

PLC controls sequence filtration cycle automatically. Pressure and flow monitoring optimize performance. Timer or pressure drop triggers cake discharge. Operator interface displays cycle status. Integration with facility automation coordinates production.

Performance Benefits

Pressure operation increases throughput versus atmospheric filters. Cake washing recovers valuable products. Enclosed system handles volatile or toxic materials safely. Automated operation reduces labor. Flexible batch processing.

Construction Standards

Pressure vessel per ASME Section VIII. Electrical systems per hazardous area classification. Materials for process chemistry. Complete system documentation with performance specifications and cycle optimization data.

ERGIL cake filtration pressure filter systems provide efficient automated solid-liquid separation forming concentrated filter cakes in pharmaceutical and chemical processing.