Patent ID: 6960072

Claim:
A hot sprue bushing for transporting plasticized material from a port on a manifold having forward and lateral flow paths to a mold cavity while controlling the temperature of the plasticized material, the hot sprue bushing comprising: an elongated body adapted to be arranged substantially perpendicular to said manifold lateral flow path, said elongated body having a material inlet end for receiving the plasticized material and an outlet end for discharging the material, said elongated body having a through passage extending therethrough from its inlet end to its outlet end for transporting plasticized material therethrough, said elongated body having an oblong cross-sectional shape in a direction perpendicular to said manifold lateral flow path and at least first and second surfaces on opposed sides of said through passage wherein said cross sectional shape of said elongated body is smallest in a direction parallel to said manifold lateral flow path; first and second continuous electrical resistance heaters disposed on said first and second surfaces respectively, said first and second continuous electrical resistance heaters each extending along at least a major portion of the length of said elongated body along a path having multiple reversing loops; and retaining means for retaining said first and second continuous electrical resistance heaters adjacent said first and second surfaces respectively and in heat conducting relationship therewith.