Cartridge filters backwashable

Backwashable cartridge filters are available in a variety of designs using metal screens, permeable ceramic, or consolidated sand as a filter medium. Filters of this type are simple and lightweight hke the disposable cartridge filters, but they have the additional advantage of being backwashable. The media used in backwashable filters typically provide filtration of particles between 10 and 75 pm. 

Backwashable cartridge filters have low solids-loading limits therefore, they have potentially short intervals between backwash cycles. It is important not to expose backwashable filters to differential pressures over approximately 170 kPa because the particles may become too deeply imbedded in the pores to be removed by backwashing. With proper maintenance and repeated backwashing, this type of filter may last up to 2 years. 

The woven wire mesh type are formed to control the open space between the wires, thereby limiting the maximum size particle that can pass through. The cartridge is installed in cases or small vessels to facilitate quick replacement, or they can be arranged for backwash by use of proper piping connections. The wire wound units have consistent spaces for uniform particle size filtering. 

Clarifying filters for liquids include the gravity-bed filters for water treatment mentioned earlier and a variety of small cartridge and edge filters of various designs. Some cake filters, especially tank filters and continuous precoat filters, are used extensively for clarification. In a batch unit, the filtration rate and solids removal efficiency are typically almost constant for a considerable period of operation, but eventually the solids content of the effluent rises to an unacceptable breakthrough value, and backwashing of the filter element becomes necessary. 

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