Method and apparatus for inserting and propelling a coating device into and through live gas pipeline

1. Field of the Invention Joints or other discontinuities in live gas pipelines are sealed by spraying the joint or discontinuity with a coating material by means of an explosion-resistant coating device (), capable of traversing long lengths of pipe (). The coating device is inserted into the pipe and uses an explosion-resistant camera () for locating joints or other discontinuities in the pipe. The preferred coating material is a high build epoxy-type elastomeric polyurethane (), which quickly cures in the presence of pressurized flowing gas. Several joints or discontinuities, spanning several hundred feet of pipe, may be coated using a single excavation.