Method for preparing the internal surface of pipe

Abstract

A method for preparing the internal surface of pipe particularly for internal coating or lining includes grinding the internal surface of the pipe and then abrasive blasting the internal surface. After grinding the internal surface of the pipe, the pipe is preferably heated to a burn-out temperature, and then sandblasted on its internal surface to produce a surface for receiving a coating or lining material. The apparatus for grinding the pipe preferably comprises a tool body and means for rotating and advancing the tool body longitudinally through the pipe to be ground. At least one grinding tool is mounted on the tool body carrying a grinding element and adapted to extend outwardly to contact and grind the internal surface of the pipe when the tool body is inserted therein. Force transmitting means, transmits the pressure of a fluid contained in a tool body cavity to each grinding tool to extend the tools and apply a grinding force to the pipe.

Dependencies are inferred from the claim text.