The Ceramic Foam Filter PPI refers to the plastic material used to make the ceramic foam and is found from the average number of pore boundaries encountered per inch. More recently the CFFs are ‘graded’ into different PPI categories according to air permeability.
The type of filtration occurring in a CFF can be divided into deep bed, cake, or mixed filtration. The filtration efficiency is dependent on the pores PPI (pores per inch) of the ceramic foam filter material, and also on the size distribution of the particulates to be removed. Ceramic foam filter efficiency is related to filter cell size. By carefully controlling cell size within the filter, a more consistent filtration performance can be achieved. Typically, removal efficiency increases as filter cell size and the metal velocity in the filter decrease.
The size ranges of typical commercial CFFs are 10 to 80 PPI. 20-40 PPI are the most commonly used, for industrial cast houses to reach both the desired casting rate and achieve minimally acceptable filtration efficiency. The 10 to 20 PPI filters have poor particle retention, and are often used for filtration of entrapped bulk, surface borne oxides, and other large particulates generated during melting, holding, and transport. High pore density filters with 60-80 PPI are only useful for quality-sensitive applications, such as surface critical extrusion and sheet products. 
Ceramic Foam Filter PPI Application in Metal Foundry
- 30ppi 40ppi Foundry Filter is the most commonly used ceramic foam filter in the aluminum casting industry.
- Ordinary aluminum casting usually uses 10-40ppi ceramic filter plates.
- Aviation and high-quality aluminum materials usually use 30-60ppi ceramic filter plates.
Alumina Ceramic Foam Filters is available in all common sizes: 7″, 9″, 12″, 15″, 17″, 20″, and 23″. We offer the whole range of porosities from PPI 10 up to PPI 60 (PPI = pores per inch). Custom-made cut-to-size filters are also possible. Ceramic foam filter has a gasket on the edges to help seat the filter in the filter box and ensure no metal bypasses the filter. There are different types of gasket available, fiber gasket, expandable gasket. Also, you can choose Alumina Ceramic Foam Filters without gasket.
