During the mid 1980's, a new thick-walled exothermic feeder concept emerged, which was trend-setting for further sleeve developments. This design later became known as the Spot Feeder. The invention was patented by Rexroth Foundry in Germany during 1985 [1]. The early sketches are still similar to today's spot feeder geometries. (Figure 1) This new design delivered several novel benefits for the foundryman, which enabled significant advances in application technology: a higher compressive strength that made it feasible to apply the feeder sleeves directly on the pattern plates of high pressure green sand moulding lines
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