Device for adjustable mounting of magnetic sensing coils used in pipe

Abstract

An adjustable mounting shoe 10 for sensing coils 31 of a pipe inspection apparatus. The mounting shoe 10 comprises a base member 12 with a recess 14 in a surface thereof in which the magnetic sensing coils 31 are mounted. A thin shim 40 of magnetically transparent material is removably supported on the base member 12 in covering relationship to the sensing coils 31 whereby the coils are protected from abrasive contact with the exterior surface of a pipe to be inspected. A pair of adjustable contact members 51 are mounted on opposite sides of the recess 14 and provided with contact surfaces 51b positioned to engage the exterior surface of a pipe while supporting the magnetic sensing coils protected by the shim in an optimum sensing range from the surface of the pipe. Means (21,22,23,60) are provided for adjustably mounting each contact member 51 for selected movement towards or away from the recess 14 for accommodating use of the sensor shoe with pipes of different diameters while maintaining the sensing coils in optimum sensing distance. The shim 40 is also replaceable if it becomes worn down by abrasive contact through extensive use or if it is desired to use a shim of different thickness if a different coil sensing range is appropriate.