Patent ID: 7915561
Filing Date: 2011-03-29
Classification: B23K

Abstract:
1. An apparatus for coating an interior surface of a pipe comprising: the pipe having an exterior surface, an interior surface and a curved longitudinal axis extending between two ends; the pipe having distortions from a cylindrical shape so that a radial distance of the interior surface from the longitudinal axis varies at positions along the pipe; an elongate support member extending continuously along the interior of the pipe between the two ends and which is curved along its length to follow the longitudinal axis of the pipe; a series of spacer straps each attached between the interior surface of the pipe and the elongate support member at spaced positions therealong for supporting the elongate support member within the pipe; the spacer straps being arranged so that the elongate support member is supported within the pipe at a position spaced from the interior surface and parallel to and above the longitudinal axis; an operating carriage mounted on the elongate support member for movement therealong; the elongate support member and the operating carriage having cooperating elements which maintain the operating carriage at a fixed rotational orientation relative to said elongate support member; the elongate support member and the operating carriage being arranged so that the operating carriage runs along the elongate support member and passes the spacer straps; an electric welding head arranged to apply parallel beads of welding material onto the interior surface of pipe to apply a coating covering the interior surface of the pipe; a head drive system carried by the operating carriage for moving the electric welding head relative to the operating carriage in directions both angularly around and radially of the elongate support member; and a carriage drive system for driving the operating carriage longitudinally along said elongate support member; wherein the head drive system comprises a multi-axis robotic arm able to dynamically adjust the electric welding head relative to the operating carriage both angularly and radially; wherein the multi-axis robotic arm comprises a three parallel axis system including a shoulder axis connected to the carriage, an elbow axis and a wrist axis connected to the electric welding head with a pair of arms between the shoulder axis and the elbow axis and between the elbow axis and the wrist axis; and where in the multi-axis robotic arm is arranged with the shoulder axis at the center of the pipe on the longitudinal axis of the pipe.