OFS Side bar - Filter Press Type OS

The OFS filter plate transport has a plate retainer. In case of sticky filter cakes, it is ensured that only one filter plate is transported. The drive is provided by an adjustable hydraulic motor. The sliding carriage is mounted to a robust chain which is guided in C-profiles. As the sliding carriage is mounted on the underside, contamination is impossible and a trouble-free operation is guaranteed. As an alternative to single shifting, 4-plate transport and register opening are available.

The automatic filter cloth cleaning system removes dirt from the filter cloths. This maintains the throughput capacity of the filter and reduces the wear of the filter cloths. The filter plate is collected by the automatic plate transport system and is positioned between two nozzle bars. By upward and downward movement of the nozzle bar the filter cloth is cleaned with washing pressures up to 100 bar. The filter plate centres itself automatically by the double-sided wash pressure and a constant cleaning effect is maintained. Integrated brushes and splash guards prevent contamination of the filter press environment.

To prevent rewetting of the dewatered filter cake, drip trays are installed under the filter plate pack. The moisture produced during filtration or automatic filter cloth cleaning is removed through the trays. Depending on the application, the drip trays are made of polypropylene or stainless steel. The drainage of the water is provided through an integrated or external launder.

Due to decades of experience, especially in chemistry and metallurgy, OFS has comprehensive knowledge of corrosion protection of filter presses. Adapted to the product characteristics, optimal measures are provided for the protection of the parts in contact with the product.

Following can be applied:

• Polypropylene- cladding
• Stainless steel- cladding
• Rubber coating
• Cylinder protection bellows
• Special painting

Depending on the filter cake properties, additional support is required for filter cake discharge. OFS offers a comprehensive range of solutions, adapted to the adhesion behavior between filter cake and filter cloth. Monitoring of the different systems is obligatory.

Available systems:

• Tilting frames
• Plate- shaking register
• Plate- shaking single plate
• Software- shaking

Air or water as inflation medium is used for membrane squeezing of the filter cake. If water is used, a multistage centrifugal pump or eccentric screw pump provides the necessary pressure behind the membranes for best possible dewatering of the filter cake. OFS supplies prefabricated units for quick assembly. These are mounted on base frames, completely piped and equipped with the necessary measuring and control technology. For safe machine operation, the filter press is equipped with SIL2 pressure switches and redundant membrane pressure relief valves.

The great advantage of filter presses is their process variability. In addition to dewatering, filter cake can be washed optionally. In this process step, the mother liquid can be replaced by another liquid or soluble salts can be washed out of the filter cake. Due to the discontinuous operation, highest wash-out degrees can be achieved. The residual filter cake moisture can be reduced by filter cake blowing. The capillary liquid contained in the filter cake is displaced by applying a pressurised gas, e.g. air or nitrogen.

Maximum results are achieved with the combination of an OFS filter plate configuration with the OFS process control.