Abstract: An apparatus for extruding pumpable materials comprising an outer conduit means connected to a material supply source said outer conduit means being arranged around two inner conduit means one of which is connected to another material supply source and the other of which is in communication with the ambient. A method for extruding one material to surround another material comprising extruding one material into a hollow extrusion to surround a supply of another material filling the center of the extrusion whereby air contained in the center of the extrusion is displaced to the ambient.