UNMATCHED EXPERIENCE

Andritz Bird is a world leader in the manufacturing and servicing of tilting pan filters. We have over 40 years of experience and have provided filters with up to 225 m² meters of filtration area. Filters are installed on activated carbon, potash, phosphate rock de-sliming, and phosphoric acid.

MAXIMUM PROCESS CONTROL

Each cell (pan) receives a metered amount of feed slurry and wash liquor.

The cell acts as its own Buchner filter. Process liquors are contained in compartmented sections of the filter without the use of rubber dams. "Short circuiting" of process liquid between filtering cells is impossible.

Cell design allows flooding of the surface of filter cake to create displacement washing, maximizing efficiency with minimum wash liquor.

The filter is equipped to manually regulate the rotating speed for process adjustment so as to change the cake thickness instantaneously. This compensates for the changing crystal characteristics coming from the reactor and maintains a constant pressure drop across the filter cloth. This feature improves water soluble recovery, reduces scale formation inside the cell vessels, and influences effective cleaning of the filter cloth.

The pre-separation distributor valve design allows accurate separation of filtrates to maximize strength of product acid going to evaporators (minimum dilution), controls strength of acid recycled back to the reactor, and maximizes efficiency of counter-current wash system. A well-sealed vacuum system allows operation at vacuum levels up to 600mm Hg. Lower pressure drops through the filtration circuit result in higher differential pressure across the filter cake, improving phosphoric acid recovery.

Feed is applied under atmospheric condition, allowing coarse solids to pre-coat the filter media. Pre-coating helps in minimizing the solids content of the filtrate and helps improving the cloth washing efficiency.

A “cloudy port” within the valve assembly further minimizes product acid dilution and solids content of product acid.

FASTDRAIN™ Vessel Process    Filtrate Profile