crudPressure leaf filters consist of pressure vessels with vertically mounted leaves accumulated on a central outlet filter manifold. There is a pneumatic vibrator or oscillating sluice header and pneumatic controlled valve at the bottom of these filters for quick removal of cake – dry or wet. There are two types of filters classified according to shell design.
- Vertical Pressure Leaf Filters.
- Horizontal Pressure Leaf filters.
Vertical Pressure Leaf Filters are very similar to horizontal leaf filters, except that the filter elements are vertical rather than horizontal. In order to allow cake or other impurities to easily exit, a butterfly valve is sandwiched between the conical bottom and discharge hopper. For opening and closing the vertical pressure leaf filter, it is provided with eye bolts and davit arm for the rotatable arrangement. This helps in removal of leafs for occasional cleaning purposes.
In the process of filtering, the slurry is pumped under pressure into a vessel that contains a stack of vertical leaves that serve as filter elements. The bottom of each leaf has a centrally located neck that 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.