Rotary Vacuum Filters are used to desweeten and dewater the mud that is separated from the juice in the clarifier.
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
| Specific Area [m2/tch] | Low | Average | High |
|---|---|---|---|
| Cuba | 0.30 | ||
| Philippines | 0.45 | ||
| Queensland | 0.46 | ||
| Natal | 0.41 | 0.69 | 1.02 |
| Hawaii | 0.69 | 0.85 | 1.02 |
| Puerto Rico | 0.20 | 0.60 | 2.23 |
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] |
|
|---|---|
| Mills | 0.72 |
| Diffusers | 0.52 |
Sugarequip of Durban and Jord of Sydney are manufacturers and suppliers.
The following standard sizes are available from Sugarequip.
| Diameter [mm] | Face width [mm] | Area [m2] | |
|---|---|---|---|
| 1 | 2440 | 3660 | 28 |
| 2 | 2440 | 4880 | 37 |
| 3 | 3500 | 7300 | 80 |
| 4 | 4270 | 9150 | 122 |
| 5 | 4880 | 10970 | 168 |
Sucrose losses as a percentage of sucrose entering the factory in filter cake are about 0.25%