Ceramic pressed filters for aluminium casting Pyral 15 ® P.Procházka, Keramtech s.r.o. Žacléř Estabilished 1878

Pic.1 – drawing of filter type no. 0825/20/H15, - size 55x55x20 mm, holes Ø 2,0 mm, 389 holes, - flow area 50% (1250 mm2), - surface area 505 cm2 Pic 2 – real picture of filter type no. 0825/20/H15, - Pyral 15® - material mullite (SiO2,Al2O3) - filter density 0,7 gr/cm3 - refractoriness up to 1500°C Ceramic pressed filter - Pyral 15 ®

1) by straining 3) deep filtration 2) by filter cake Filtration process

Filter efficiency by straining and filter cake oxide skins

Filter function – form filling Pressed filters have control over quantity and speed of flow rate by form filling: - absorbe first pouring shock – quarantee stable quantity of melt in anytime during pouring process - very important influence for casting quality, eliminate surface deffects, improve

Direct cylindrical holes of pressed filters change turbulent flow to streamline flow : - ensure quiet filling of form - decrease turbulent energy behind the filter – eliminate re-oxidizing processes = eliminate new oxide skins and inclusion Filter function – form filling

Recommended placing Under the sprue In the channel

Advantages of Pyral ® 15 filter 1. flat and smooth sides & round corners: - fit easily with filter print mark - reduce damage of filters - eliminate creation of new inclusion 2. exactly defined flow area: - always the same number and Ø of holes guarantee stable flow rate - availability of real computer simulation 3. exactly defined surface/effective area - the effective surface area is always the same – quarantee of stable filtration efficiency 4. porosity of surface - Pyral 15 is high porosity material – high inclusion adhesion improve filtration effeciency

Resume of pressed filters Pyral 15 ® Pyral 15 ® filters guarantee very stable casting process Filtration efficiency of pressed filters is comparable to foam filters Using Pyral 15 ® filters is without any limitation Pyral 15 ® filters keep form after casting process and could be easily removed by remelting process Pressed filters are packed tightly in carton box - minimum stocking place is required

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