Insulating space between pipeline and outer casing - with foam supplied by mixing head drawn through space at velocity coordinated with foaming operation

摘要

Filling of hollow spaces esp. between a pipeline and an outer casing, with insulating material is effected by introducing a liquid, foamable reaction mixt esp. for prodn of a polyurethane foam, into the hollow space by means of the outlet nozzle of a mixing head. This head is drawn through the hollow space at a velocity coordinated with the foaming operation. Effective filling of hollow spaces of great length. The foam materials bonds to both the pipeline and the outer casing. Seamless casings can be used.