Patent Number: 
Section: claims

1. A device for inspecting and measuring weld defects in a cylindrical wall of a cylindrical conduit, comprising:an inspection head forming a probe having a proximal end and a distal end along its longitudinal axis, and of which a first side called “inner side” is provided with at least one ultrasound wave transducer, wherein:the inspection head comprises a second side, called “outer side” opposite the first side that has a curved surface in the form of a cylinder fraction, with a second longitudinal axis parallel to the longitudinal axis of the inspection head, and wherein the curved surface of the second side has outward facing convexity;the wave transducer is formed of a series of juxtaposed elements, each element being both a transmitter and receiver, wherein a surface of the series is curved and in the form of a cylinder fraction having a third longitudinal axis that is co-planar with the longitudinal axis of the inspection head, and wherein the surface of the series has outward facing concavity; anda first plane parallel to the first side and a second plane parallel to the second side, wherein an angle between the first plane and the second plane is a nonzero acute angle β. 2. The device according to claim 1, wherein the angle β is approximately 21°. 3. The device according to claim 1, wherein the elements of the series are arranged one behind the other. 4. The device according to claim 1, wherein each element of the series is subdivided into several sub-elements distributed in a two-dimensional array, so that each sub-element has at least one neighbouring sub-element in a longitudinal direction and at least one neighbouring sub-element in a transverse direction. 5. The device according to claim 1, further comprising a manipulating pole having the inspection head at a distal end thereof. 6. The device according to claim 1, wherein a radius of curvature of the series of elements is between 8 and 30 mm. 7. The device according to claim 2, wherein the elements of the series are arranged one behind the other. 8. The device according to claim 6, wherein the radius of curvature of the series of elements is 10 mm. 9. A method for inspecting and measuring weld defects in a cylindrical wall of a cylindrical conduit, comprising:providing a device comprising an inspection head forming a probe having a proximal end and a distal end along its longitudinal axis, and of which a first side called “inner side” is provided with at least one ultrasound wave transducer, wherein:the inspection head comprises a second side, called “outer side” opposite the first side that has a curved surface in the form of a cylinder fraction, with a second longitudinal axis parallel to the longitudinal axis of the inspection head, and wherein the curved surface of the second side has outward facing convexity;the wave transducer is formed of a series of juxtaposed elements, each element being both a transmitter and receiver, wherein a surface of the series is curved and in the form of a cylinder fraction having a third longitudinal axis that is co-planar with the longitudinal axis of the inspection head, and wherein the surface of the series has outward facing concavity; anda first plane parallel to the first side and a second plane parallel to the second side, wherein an angle between the first plane and the second plane is a nonzero acute angle β;inserting the inspection head inside the cylindrical conduit, wherein the outer side of the inspection head has a same radius of curvature as an inner wall of the cylindrical conduit;applying the outer side against the inner wall; andscanning at least part of the inner wall during which the outer side remains in contact with the inner wall. 10. The method according to claim 9, further comprising:moving the inspection head in successive longitudinal movements inside the cylindrical conduit, and moving the inspection head in an angular movement between each longitudinal movement. 11. The method according to claim 9, further comprising:moving the inspection head in successive angular movements inside the cylindrical conduit, and moving the inspection head in a longitudinal movement between each angular movement.