Sweetland filter

Filtration is the most straightforward, probably the oldest form of sugar liquor clarification process. Filtration is effected with plate and frame pressure-filters or some type of leaf pressure-filter such as Sweetland filters with stationary suspended circular leaves covered on both sides with filter cloth. A filter aid of some sort (diatomaceous earth, paper pulp, or kieselghur) is essential to the operation. The precipitated calcium carbonate serves as a filter aid in the carbonation process. The liquor is mixed with the filter aid and forced under pump pressure through the fabric, which retains the cake and allows the clear liquor to flow through. The retained sugar in the cake can be washed out with hot water. Filtration is no longer used as the sole means of clarification. The process is used for further clarification of the liquor from a carbonation or phosphatation process. 

The Sweetland filter is a frame press arranged so that the bottom can be lowered as a unit in order to remove the cake quickly by washing it out. 

Fig. 10-5. Sweetland filter press for removing fine clay.

Table 10-11, Capacity of Sweetland Filter Presses Oliver United Filters, Inc.. ...

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