Filtration with diatomite suspensions in the beverage industry

For metering filter aids during filtration, the LEWA ecodos sanitary/hygienic design is an optimum solution, because it is designed for handling diatomite suspensions.

• LEWA ecodos sanitary/hygienic without a stuffing box has a surface quality of 0.5 µm and is suitable for continuous operation
• Valves are of the SA design with valve seat inserts made of VA 80 and equipped with dairy pipe connections
• Hermetic seal of the pump prevents contamination of the product
• Patented 4-fold safety diaphragm made of PTFE, diaphragm and seal are FDA-compliant
• During the filtration process, the pump continuously pushes the liquid with the diatomite suspension through, so that the filter cake remains porous at the filter plates
• Extremely small dead space makes it easy to clean the entire pump and provides for sterility of the product
• Cleanable with CIP/SIP

Before the bottling, beverages like beer, wine or fruit juices have to be filtered, which means, undesired solids have to be separated from the fluid. For successful filtration, a filter aid is needed. An example for such a filter aid is kieselguhr, which filters out yeast and protein components of high molecular weight. The filtration process begins with a precoating of the filter plates.

A consistently distributed kieselguhr suspension is metered into a water flow or directly into the product. From then, kieselguhr has to be added constantly, so that the filter cake remains porous. Because of the added filter aid, the filter cake grows continuously and increases the filter depth. If enough kieselguhr is dosed, the lifetime of the filter can be optimized.