Pressure Leaf Covers
In most pressure leaf filters, a filter cover fits over a frame (leaf) in a pressure vessel. The chamber is filled with slurry and pressure forces liquid through the cloth, into the leaf and out of the drain port. This type is usually a polishing filter used to filter what was missed up-stream (in a previous filtering process).
Pressure Leaf Filter Styles
Among pressure leaf filters, the Vertical Tank - Vertical Leaf Filter is lowest in cost and has the lowest volume-to-area ratio. They are available for wet and dry cake discharge.
Since the Horizontal Tank - Vertical Leaf Filter is made so that the leaves can be rolled from the filter quickly, they can be easily inspected for tears in the septum, leaks around the edges of the screens or around the gaskets in the manifold, improper precoating, etc.
The Rotating Leaf Filter is particularly adapted for installations where the cake is very difficult to remove by sluicing. It is designed so that the leaves can be rotated with the sluice sprays on, allowing the entire area of the leaf to receive the full force of the sluice jet.
All of the above pressure leaf filters have the cake held on the filter element by means of a differential pressure drop across the element, set up by flow of liquid through the element. If the operation is intermittent, the Horizontal Leaf Filtercan be used to advantage. This filter may be designed so that the leaves and septa are assembled as a unit outside the filter, or with rotating leaves in the filter for discharge by a secondary sluice.
Another form of pressure leaf style filters is the horizontal Kelly Filter or vertical style Baker Filter. They are designed to create large filtration areas and to handle primarily viscous liquid, such as concentrated sugar solutions and green liquor in alumina refineries.
- Food (sugar, salt)
- Alumina (green liquor)
Menardi provides filter leaf covers required for all kinds of leaf filters. The material can be supplied in the form of rolled goods or pre-fabricated as per leaf filter sizes. The fabrics are selected after thorough understanding of the filtration process and results desired. A variety of filter closures are available including zippers, Velcro®, draw strings, snapcords, and sew flaps.