Feeder system

A feeder system for metal casting, the feeder system comprising a feeder sleeve mounted on a breaker core,

• the feeder sleeve having a first end and an opposite second end, a longitudinal axis extending between the first and second ends, and a continuous sidewall extending generally around the longitudinal axis between the first and second ends, the sidewall defining a cavity for receiving molten metal during casting, and
• the breaker core defining an open bore therethrough for connecting the cavity to the casting,
• wherein the first end of the feeder sleeve is mounted on the breaker core, and
• the feeder sleeve comprises a plurality of discrete protrusions extending from an exterior surface of the sidewall at the second end of the feeder sleeve, and
• wherein the protrusions extend outwardly from the sidewall to a distance of 5-35% of the maximum diameter of the sidewall at the second end of the feeder sleeve, and
• wherein the protrusions extend from the second end towards the first end along 5-20% of the maximum height of the feeder sleeve, as measured in the direction of the longitudinal axis, and wherein the bottom of each protrusion is rounded, and
• wherein each protrusion extends around less than 15% of the circumference of the sidewall at the second end of the feeder sleeve.