The initial operation of a filter press with membrane plates is identical to that of its recessed chamber counterpart. However, once the filtration cycle is complete and final filtration pressure is achieved, the feeding of the filter press is stopped.
At this point, the membrane plates can be inflated using water to exert a mechanical force on the filter cake retained in the chamber. The effect of the squeeze is to physically compress the filter cake and force out additional moisture held within the cake giving a drier end result.
Membrane plates are used to:
- Reduce filter cake moisture content
- Reduce filtration cycle time
- Improve cake washing
This style of plates can be installed as:
- A full plate pack
- Alternately in conjunction with recessed plates as a more economical option.
MEMBRANE PLATE TECHNOLOGY
The membrane technology is gaining increased acceptance because it reduces subsequent processing or disposal costs for filter cake. In many applications the membrane plates significantly reduce residual moisture content, making this technology attractive for new plants and for upgrading existing facilities. In both cases the careful selection of plate and membrane materials is essential to the successful performance of the process.
Membrane Plates have a chamber below the drainage surface that can be inflated. The common method used is water pressure, which is generated by pumping into the squeeze cavity to inflate the face of the plate against the filter cake. Membrane Plates are used to reduce the cake moisture content & shorten the filtration cycle time.
Mix Pack Membrane are the most common configuration (one recessed plate then one membrane plate alternate in the press plate pack). Membrane Plates usually operate at a squeeze pressure up to 17 bar. Special plates can be designed for higher feed & squeeze pressure.
Replaceable membranes can be changed easily. EPDM thermoplastic and other compounds are used for specific conditions. Plate filling problems are minimized and the use of a rubber Membrane enables “empty-chamber” operation without damaging the plate, resulting a considerable reduction in incidents of plate failure. Even if the chamber is not completely filled, the filter cake is squeezed by the inflating filter lever and therefore perfectly dewatered.