OFS Overhead - Filter Press Type OH and Type OZ4
OFS Overhead – Filter Presses impress with their robust construction and free access to the filter plate pack. Regardless of whether it is used as a chamber filter press or as a membrane filter press, the individual filter plate interlocking guarantees a defined filter cake discharge. Minimum discharge times of the filter cake are achieved by the circulating plate transport. The separation of all moving parts from the product side allows maximum corrosion protection and maximum product purity.
OFS Overhead – Filter Presses are characterised by their production-oriented design and perfected detail engineering. OFS overhead filter presses guarantee best filtration results and maximum throughput at lowest operating and maintenance costs.
OFS offers two different types of overhead beam machines adapted to the application. With the overhead filter press type OH the filter plate package is pressed together by a push to close cylinder. The closing forces are absorbed by the beam at the top and the tie rods at the bottom. An alternative construction is the overhead filter press type OZ4. The plate pack of this type is held together by tension cylinders arranged at the outer corners of the frame. The closing forces of this design are absorbed by four tie rods. Due to their special design OFS overhead filter presses type OZ 4 are particularly suitable for large machine volumes. Through the constructive force separation of the plate weight from the closing mechanism, enormous filter plate sizes, package lengths and process pressures can be realised.
OFS System Solution
OFS supplies complete filtration systems to optimise your production, with minimum downtime and maintenance. If desired, OFS experts will support you during the entire plant life cycle.
- Feeding system
- Membrane inflation system
- Fittings and instruments
- Splash protection devices
- Cake weighing equipment
- Filter cake transport equipment
- Plant control systems
- Examination of plant safety
- Service solutions and service contracts
Overhead filter press type OH
- 800 x 800 mm
- 1000 x 1000 mm
- 1200 x 1200 mm
- 1500 x 1500 mm
- 1500 x 2000 mm
- 2000 x 2000 mm
- 2500 x 2500 mm
from 10 m² up to 2200 m² filter area.
Overhead filter press type OZ4
- 1500 x 1500 mm
- 2000 x 2000 mm
- 2500 x 2500 mm
from 200 m² up to 2200 m² filter area.
Optional machine equipment
A circulating chain with carriers is mounted in the overhead beam. The filter plates are attached to transport trolleys that run on rails in the bridge. The transport trolleys are interlocked so that only one filter plate is transported at a time and a defined cake discharge takes place. By moving the chain, the carriers unlock the transport trolley and transport the plate. Due to the number of carriers and the chain speed, discharge times of less than 2 seconds/plate are achieved.
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.
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.
- Tilting frames
- Plate- shaking register
- Plate- shaking single plate
- Software- shaking
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
- In the case of overhead machines, additional separation of the plate transport by plate suspension with lashes and traverse and installation of a tarpaulin .
- Cylinder protection bellows
- Special painting
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.