The plate filter equipment mainly filters the aluminum liquid through the ceramic foam filter. The foam ceramic filter plate is currently the most effective tool for removing the oxide inclusions in the aluminum melt. General fiber filtration can only remove large inclusions, while the foam ceramic filter plate can simultaneously filter out large inclusions and small inclusions.
The ceramic foam filter plate has a multi-layer network and multi-dimensional through holes, and the holes are communicated with each other. During filtration, the molten aluminum carries inclusions and flows along the tortuous channels and pores, and is directly intercepted, adsorbed, deposited, etc. when it comes into contact with the foam-like framework of the filter plate. When the melt flows in the hole, the filter plate channel is curved, the melt flowing through the channel changes the flow direction, and the inclusions collide with the hole wall and adhere firmly to the hole wall.
When designing the plate filter equipment, it should be based on the specifications of the ceramic foam filter plate to be selected, and considering the drop of the furnace mouth and the splitter plate, it must be ensured that the filter plate is immersed in the molten aluminum during the melt casting. In addition, it must be considered that the installation and disassembly are very safe and convenient, and the aluminum liquid in the filter box can be completely drained after the melt is cast.
The closer the plate filter equipment is to the splitter plate, the filtering effect better. Because this can shorten the flow distance of the aluminum liquid after filtering, thereby reducing the re-generation of oxides. The molten aluminum flows out of the furnace mouth, passes through the filter box, and then flows into the splitter plate through the launder. When the filtering device is started, the drop before and after the melt filtering is about 50 mm. With the extension of the filtration time, the inclusions on the surface of the filter plate and the hole wall increase, the filtration flow decreases, and the front and back drop increases. At the end of casting, the drop has increased to 60 ~ 120 mm. The choice of ceramic foam filter plate must be based on the flow of molten aluminum. Secondly, the cleanliness of the melt, the highest content of inclusions and the total throughput of the melt should be considered.
The filtering effect of the filter plate is mainly ensured by its size and porosity. The larger the pores of the filter plate, the worse the slag removal effect. For aluminum castings with strict requirements, filter plates with small pores should be selected.