The heart of the Pannevis RT filter is a continuously moving filter cloth that does not require a rubber support belt. Instead an open grid located in a profiled tray running the length of the filter supports the filter cloth. The vacuum for separation of the solids and liquid is applied to the underside of the cloth. When vacuum is applied, the forward movement of the cloth pulls the tray with it at the same speed as the cloth. When the tray has advanced to a specified point, the vacuum is briefly removed from the underside of the tray, while, at the same time, the tray is retracted to its original position. Vacuum is then reapplied and the tray again begins to advance with the cloth.
The RT filter can be used for multiple wash steps, either co-current or counter-current, vibration, hot air drying, cooling, steaming or mechanical compression, any or all such steps in almost any combination. They can also be offered with gas-tight or pressure-tight enclosures, allowing safe operation of processes involving flammable materials, explosives, hazardous materials, or any process where containment is a critical factor.
The ability to carry out multiple wash steps, with each wash filtrate precisely collected into its own receiver enables the Pannevis RT filter to produce very high purity products with low wash water consumption. Washing can be done with more than one liquid and can be either co-current or counter-current. Very high purity cakes, up to 99.99% or better, can be produced.
The RT filter is also a very efficient dryer after the dewatering process is completed. Filter cakes are relatively thin, usually between 6 and 100 mm (1/4” - 4”), so drying is achieved quickly with final moisture contents down to 0.1% possible. Rapid drying also allows a higher gas temperature to be used, since the cake will normally not reach the gas temperature except at the end of the cycle.
For solvent wetted materials, a gas-tight enclosure with full nitrogen blanketing is used. Equally, steaming or cooling of the filter cake can be accomplished using the drying procedure by substituting steam or a coolant for the hot air.
Pannevis Filter Options - Pannevis filters can be used for the following operations:
Continuous separation of slurries into filter cake and clear filtrate Washing of the filter cake in the following configurations:
- Co-current washing of the filter cake
- Counter-current washing of the filter cake
- Reflux counter-current washing of the filter cake (coarse materials only)
- Leaching of the filter cake using either co-current or counter-current extraction
- Co-current or counter-current chemical reaction of the filter cake
Mechanical compression of the filter cake to increase dry solids content using:
Thermal drying of the cake using:
- Hot gas (air, nitrogen or steam)