1. Provisions for mold filtration

The retention of impurities during the casting of alloys is one of the foundryman's preoccupations in his ongoing quest to improve the quality of his castings.

To trap them, in whole or in part, a number of well-known devices were already available in the past, some of which were placed in the mold, such as dross traps or fiberglass filters. Others were located outside the mold, such as filtration on [1] and [2] aggregates, or the retention of "dross" by funnels or specially designed pouring basins [79] ; not forgetting "teapot" or "cattail" type pouring ladles [3] .