Method and a device for inspecting a pipe connection weld by an ultrasound probe

A method of inspecting a substantially circular circumferential weld for connecting an inner pipe to a coaxial outer pipe, either directly or else via a junction forging, inspection being performed by an ultrasound probe, the method comprising the steps of:

• using a robotic ultrasound probe comprising a plurality of multibeam piezoelectric emitter-receivers;
• a) positioning at least one said ultrasound probe inside said inner pipe, at a given position in the longitudinal axial direction of said inner pipe against the inside surface of the wall of said inner pipe, said given position facing or being close to said weld, so that the ultrasound beams from the various emitters in the axial plane of said inner pipe perpendicular to the plane of the bottom faces of said emitters cover at least the entire width of the weld in said longitudinal axial direction from the external tip to the root of said weld at the interface with said inner pipe;
• b) causing the various ultrasound beams of the various emitters of said probe to scan while the probe is positioned in said given position;
• c) moving said probe in rotation about the longitudinal axis of said pipe through a given angle of rotation;
• and then
• d) repeating steps b) and c) until the entire circumference of said weld has been inspected;
• wherein said weld is on the outside of said pipe;
• and
• wherein said weld connects the end of said outer pipe to the outside surface of the wall of said inner pipe, the end of said outer pipe being set back from the end of said inner pipe.

A device for inspecting a circumferential weld and usable to inspect a substantially circular circumferential weld for connecting an inner pipe to a coaxial outer pipe either directly or else via a junction forging, the device comprising:

• at least one robotic ultrasound probe comprising a plurality of multibeam piezoelectric emitter-receivers;
• mechanical support means for supporting said probe in position against the inside surface of the wall of said inner pipe;
• motorized displacement means for moving said probe in translation along the longitudinal axial direction of said inner pipe and in rotation about the longitudinal axis of said inner pipe, enabling it to travel around the circumference of the inside surface of said inner pipe;
• automatic electronic control means for said probe displacement means;
• and
• electronic means for analyzing and controlling the signals from said probe and connected to said probe;
• the device further comprises:
• a structure suitable for fitting, with the help of fastener means, to the end of said inner pipe or to the end of said junction forging;
• said structure having a central guide cavity in which a shaft is axially mounted and is suitable for being driven in axial translation inside said inner pipe;
• said shaft being suitable for being driven in rotation about its longitudinal axis, and including at its end a transverse arm extending radially relative to the longitudinal axis of said inner pipe and being suitable for being driven in rotation by rotating said shaft;
• and
• said probe being mounted at the end of said arm.

A method of coupling an inner pipe with a coaxial outer pipe in an assembly of two coaxial pipes, the method comprising the steps of:

• welding the end of said outer pipe on the surface of said inner pipe so as to form a circular circumferential weld;
• and
• inspecting said weld with a device comprising:
• at least one robotic ultrasound probe comprising a plurality of multibeam piezoelectric emitter-receivers;
• mechanical support means for supporting said probe in position against the inside surface of the wall of said inner pipe;
• motorized displacement means for moving said probe in translation along said longitudinal axial direction of said inner pipe and in rotation about the longitudinal axis of said inner pipe, enabling it to travel around the circumference of the inside surface of said inner pipe;
• automatic electronic control means for said probe displacement means;
• and
• electronic means for analyzing and controlling the signals from said probe and connected to said probe;
• the device further comprises:
• a structure suitable for fitting, with the help of fastener means, to the end of said inner pipe or to the end of said junction forging;
• said structure having a central guide cavity in which a shaft is axially mounted and is suitable for being driven in axial translation inside said inner pipe, with the help of jacks or an electric motor;
• said shaft being suitable for being driven in rotation about its longitudinal axis, with the help of an electric motor, and including at its end a transverse arm extending radially relative to the longitudinal axis of said inner pipe and suitable for being driven in radial translation, and being suitable for being driven in rotation by rotating said shaft;
• and
• said probe being mounted at the end of said arm, via a hinge or ball joint.

A method of connecting together two unit elements of a set of two coaxial pipes each comprising an inner pipe and an outer pipe comprising the steps of:

• assembling a junction forging to the ends of said inner and outer pipes of each unit element of a set of two pipes by welding said forging to said ends of the inner and outer pipes;
• and
• inspecting the circular circumferential weld between said forging and the end of the inner pipe by using a device comprising:
• at least one robotic ultrasound probe comprising a plurality of multibeam piezoelectric emitter-receivers;
• mechanical support means for supporting said probe in position against the inside surface of the wall of said inner pipe;
• motorized displacement means for moving said probe in translation along the longitudinal axial direction of said inner pipe and in rotation about the longitudinal axis of said inner pipe, enabling said probe to travel around the circumference of the inside surface of said inner pipe;
• automatic electronic control means for said probe displacement means;
• and
• electronic means for analyzing and controlling the signals from said probe and connected to said probe;
• the device further comprises:
• a structure suitable for fitting to the end of said inner pipe or of said junction forging with the help of fastener means;
• said structure having a central guide cavity in which a shaft is axially mounted and is suitable for being driven in longitudinal axial translation inside said inner pipe, with the help of jacks or an electric motor;
• said shaft being suitable for being driven in rotation about its longitudinal axis, with the help of an electric motor, and including at its end a transverse arm extending radially relative to the longitudinal axis of said inner pipe and suitable for being driven in radial translation, and being suitable for being driven in rotation by rotating said shaft;
• and
• said probe being mounted at the end of said arm, via a hinge or ball joint.