These type of filters are all fed continuously for a certain amount of time. Then feed is stopped and next batch steps follow, like cake wash, cake blow and cake discharge. Total batch or cycle time can vary from 15 minutes with fast cycling pressure filters up to 5 and also 10 hours in case of nutsche filter-dryers.
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Plate Pressure Filter - the work horse of the industry. Around for many years. Filtration pressures up to 8, 12 and 16 bar and higher for special applications. Mainly recessed plates are used with or without squeezing rubber diaphragms that manage to squeeze out some 5% more moisture. These filters can be executed for full manual operation, semi-automatic and fully automatic operation. Most common cake height is 3 cm. Filter is mainly used for water slurries, not solvents, because filter cake is discharged by separation of the recessed filter plates.
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Fully enclosed plate pressure filter – smaller filters built in pressure housing. Makes them suitable as well for solvents. Mainly used in API and pharma.
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Agitated Nutsche Filter - used for applications that allow high cake filtration above 10 cm cake height. Very popular for batch filtrations where also consequent cake drying is required. Suitable for solvents because filter is totally closed. Both filter bottom, jacket and agitator can be heated. Most common filtration pressure about 3 bar. These filters also allow operation under full vacuum which assist the drying step.
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Disc Filter – mostly used as polishing filter where feed solids content is low. After cake is built, filter discharges by rotating the discs and cake is discharged by centrifugal force.
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