Rotary Vacuum Filters

Rotary Vacuum Filters are used to desweeten and dewater the mud that is separated from the juice in the clarifier.

Filter Sizing

The size of the filters required depends on the amount of mud that is produced by the clarifier which is in turn proportional to the amount of cane crushed

Hugot provides the following table

 Specific Area [m2/tch]
 LowAverageHigh
Cuba 0.30 
Philippines 0.45 
Queensland 0.46 
Natal0.410.691.02
Hawaii0.690.851.02
Puerto Rico0.200.602.23

These variations are due to different climates, cane varieties and agricultural practices

Peter Wright in Professor Rein's new book Cane Sugar Engineering quotes similar figures for South Africa, Australia and India.

In diffusion factories much less mud is collected in the clarifier as the bed of cane in the diffuser tends to act as a filter and much of the mud is retained in the bagasse. This is reflected in the table of data from South Africa below

 Specific Area
[m2/tch]
Mills0.72
Diffusers0.52

Suppliers

Sugarequip of Durban and Jord of Sydney are manufacturers and suppliers.

Standard Sizes

The following standard sizes are available from Sugarequip.

 Diameter [mm]Face width [mm]Area [m2]
12440366028
22440488037
33500730080
442709150122
5488010970168

Sucrose Losses in Filter Cake

Sucrose losses as a percentage of sucrose entering the factory in filter cake are about 0.25%