Vertical Pressure Leaf Filters are quite similar to the Horizontal Plate Filters except for the orientation of the filter elements which are vertical rather than horizontal. They are applied for the polishing slurries with very low solids content of 1-5% or for cake filtration with a solids concentration of 20-25%.
Just like the Horizontal Plate Filter the Vertical Leaf Filters are also very well suited for handling flammable, toxic and corrosive materials since they are autoclaved and designed for hazardous environments when high pressure and safe operation are required. Likewise, they may be readily jacketed for applications whenever hot or cold temperatures are to be preserved. These features are not possible on Filterpresses which require the opening of plates to the atmosphere and shifting them one by one to allow cake discharge at the end of each cycle.
The largest vertical pressure Leaf Filters have a filtration area of 90 m2 and designed for an operating pressure of 6 bar
The slurry is pumped under pressure into a vessel that is fitted with a stack of vertical leaves that serve as filter elements. Each leaf has a centrally located neck at its bottom which is inserted into a manifold that collects the filtrate. The leaf is constructed with ribs on both sides to allow free flow of filtrate towards the neck and is covered with coarse mesh screens that support the finer woven metal screens or filter cloth that retain the cake.
The space between the leaves may vary from 30-100 mm depending on the cake formation properties and the ability of the vacuum to hold a thick and heavy cake to the vertical leaf surface. The space is set by the filtrate necks of the leaves at the bottom end and with spacers at the top end brackets.
For fast filtering slurries the space may be doubled by removing every second plate so consequently the cake space doubles but the filtration area is cut in half.
━ Edible Oils
━ Bio fuels
━ High filtrate clarity
━ High yield low product losses
━ Large filtration area – small footprint (high headroom)
━ No filter cloth – no washing or cloth replacements
━ Totally enclosed operation – no contact with air/moisture
━ Positive pressure – no vacuum or lowered pressures necessary
━ Wet or dry cake discharge
━ Possible extraction of the filter cake within the filter
━ Easy to automate – operation with minimum labour
━ Fast and effective cleaning without manual interference.
━ Mechanically simple
━ Easy access to the filter leaves for maintenance or extra leaf cleaning
━ Intensive cleaning of filter medium is possible
━ Improved housekeeping
━ Steam heating optional