Apparatus for introducing a foamable plastic insulation into the space defined by an inner core pipe and an outer casing pipe while maintaining the spacing of the pipes

摘要

This invention relates to insulated pipe and methods and apparatus for making the same. There has been difficulty in placing foamable insulating materials in the narrow elongated space between a casing pipe and a core pipe. According to the instant invention, a miniaturized mix head is inserted in this elongated space. Constituents of the foamable insulating material are simultaneously mixed and disseminated by the mix head in a manner to create a moving foam front which displaces air within the elongated space and permits the formation of a layer uniform, low density insulating material therein.