Abstract: A process of renovating pipes wherein a particulate abrasive agent is passed through the pipe to loosen the internal deposits. The process involves initially drying the pipe by drawing preheated air through the pipe, then drawing the abrasive agents through the pipe, and then coating the inner wall of the pipe with a metered quantity of a viscous hardening coating material. All of these steps may include the application of a suction to one end of the pipe, so that the pipe is always exposed only to a low pressure.

Abstract: A process for renovating pipes wherein a particulate abrasive material is passed through the pipe to loosen the internal deposits, and after the abrasive material and internal deposits are removed from the pipe, a coating of a curable resinous or plastic material is applied to the interior of the pipe. An alternately produced pressure drop between the two ends of the pipe is employed to cause the particulate abrasive material to reciprocate within the interior of the pipe and thereby effectively loosen the internal deposits and avoid cloggages resulting from the loosened and detached internal deposits.