Apparatuses for producing tight joints or seals in underground pipelines

摘要

A method of rejoining seals at joints in underground pipelines comprises moving a carriage inside a pipeline beyond a joint to be reformed and rapidly spraying a synthetic polymerizable material to cover the joint from a spraying head mounted on the carriage and displaced relatively slowly with respect thereto. The carriage has means for propelling it on rolling members, for anchoring it in the pipeline, and for moving an arm on which the spraying head is mounted.