The open pore volume of the foam ceramic filter is 75% to 90%, which is usually classified according to the number of holes per inch (ppi) on the line. Such as 10 ppi foam ceramic filter, its pore size is 1778 μm, the range is 584 ~ 3708 μm; 30 ppi foam ceramic filter, its pore size is 711 μm, the range is 229 ~ 1422 μm. The thickness of the foam ceramic filter is generally 25 mm. There are vertical and horizontal installations in the pouring system, the structure of which is designed according to the specific use.
Foam ceramic filters have used materials such as NCL-Mullite, ZrO2, Zr-SiO4 and Al2O3. Using Al2O3 foam ceramic, it is not easy to break during operation, and its thermal shock resistance is good. Under the flow of 1700 ℃ high temperature metal liquid, it has strong resistance to creep deformation. Because the porosity of the open pores is high (75% to 90%) and the pore walls are very thin, the foam ceramic filter does not need to be preheated before contacting with the molten metal.
