Ultrasonic inspection apparatus for a spherical body

1. A spherical body inspection apparatus comprising:

a support arrangement realized to support a spherical body during an inspection procedure;

a probe arrangement comprising a plurality of ultrasonic testing probes arranged about the spherical body such that the ultrasonic testing probes simultaneously target a common test point at the surface of the spherical body and at least one of the plurality of ultrasonic testing probes is arranged to emit an ultrasonic pulse that enters and exits the spherical body at the common test point and passes as a longitudinal wave through the spherical body and at least one other of the plurality of ultrasonic testing probes is arranged to emit an ultrasonic pulse that, after refraction into the spherical body, passes as a transverse wave along a chord of the spherical body to the common test point; and

a displacer for effecting at least one relative rotational displacement between the spherical body and the probe arrangement.

2. The inspection apparatus according to claim 1 , wherein the displacer comprises a rotator realized to rotate the spherical body about a first axis of the spherical body and/or a probe displacer realized to rotate the probe arrangement about a second axis of the spherical body.

3. The inspection apparatus according to claim 2 , wherein the first axis and the second axis are orthogonal axes passing through the centre of the spherical body such that successive test points describe a loxodrome on the spherical body.

4. The inspection apparatus according to claim 3 , comprising a controller realized to control the rate of rotation of the spherical body and/or the rate of rotation of the probe displacer.

5. The inspection apparatus according to claim 1 , wherein the at least one other of the plurality of ultrasonic testing probes is held to subtend a predetermined angle of incidence relative to a central axis of the spherical body to achieve a desired refraction angle.

6. The inspection apparatus according to claim 1 , wherein an ultrasonic testing probe of the plurality of ultrasonic testing probes comprises a focused ultrasonic testing probe having a focal length, which ultrasonic testing probe is held at a distance from the spherical body corresponding essentially to the focal length of that ultrasonic testing probe.

7. The inspection apparatus according to claim 1 , wherein the probe arrangement comprises a set of matched ultrasonic testing probes.

8. The inspection apparatus according to claim 1 , further comprising an acquisition unit for recording reflected ultrasonic pulses detected by the ultrasonic testing probes.

9. The inspection apparatus according to claim 1 , further comprising an analysis unit for analysing the recorded ultrasonic pulses to determine the presence of an anomaly in the spherical body.

10. The inspection apparatus according to claim 1 , realized for use in an immersion tank.

11. A method of inspecting a spherical body, which method comprises:

arranging a probe arrangement comprising a plurality of ultrasonic testing probes relative to the spherical body such that the ultrasonic testing probes simultaneously target a common test point at the surface of the spherical body with at least one ultrasonic pulse that enters and exits the spherical body at the common test point and passes as a longitudinal wave through the spherical body and at least one ultrasonic pulse that, after refraction into the spherical body, passes as a transverse wave through the spherical body along a chord to the common test point; and

actuating the ultrasonic testing probes to emit the ultrasonic pulses while

effecting at least one relative rotational displacement between the spherical body and the probe arrangement of the ultrasonic testing probes.

12. The method according to claim 11 , wherein a rate of rotation of the spherical body and a rate of displacement of the probe arrangement are chosen to achieve an essentially complete coverage of the surface of the spherical body by a path described by a succession of test points on the surface of the spherical body.

13. The method according to claim 11 , wherein, in a first relative rotational displacement, the spherical body is rotated through a plurality of complete revolutions about a first axis while, in a second relative rotational displacement, the probe arrangement is displaced at least through a space containing one hemisphere of the spherical body.