Interlocking ceramic tile for covering an insulated water cooled pipe structure

A preburned ceramic refractory shape formed as a segment of ring-like configuration having substantially parallel edge surfaces, one of the edge surfaces having an arcuate protuberance thereon and the opposite edge surface having an annular recess therein symmetrically arranged with respect to the protuberance, a semi-cylindrical inner surface substantially perpendicular to the edge surfaces and having parallel arms extending beyond and with their inner surfaces merging with the inner surface of the shape, an external segment of a cylindrical surface co-axial with and spaced outwardly of the inner semi-cylindrical surface and the surface extended to define an exterior surface of the arms, one of the edge surfaces of the shape being substantially flat throughout its extent including the arms, the other edge surface having symmetrical recessed portions including each arm extending through the shape, each recessed portion including a hook therein, some of the surfaces of the recessed portion lying in radial planes passing through a common axis of the inner and outer curved surfaces.