An insulating concrete shell made of refractory cast concrete or refractory tamped concrete for insulating uprights or supporting tubes in a walking beam furnace or pusher-type furnace. The insulating concrete shell is shell-shaped and has a sheet metal strip on the inner side at each end, with which the insulating concrete shell can be fastened to an upright or to a supporting tube. The two sheet metal strips are connected to each other by wires, whereby the two wires are completely embedded in the cast or tamped concrete. A method for manufacturing an insulating concrete shell is also disclosed.

A pressure ring assembly (10) comprises at least first and second segments 12.1, 12.2 which are connected to one another in abutting relationship by a removable wedge connector 14 comprising first and second prongs 36, 38. Each segment comprises a body 20 extending arcuately between first and second side walls 22, 24 thereof. Each segment defines first and second elongate bores 26, 28. Each bore has a radiused wall section 30 facing the adjacent side wall, the radius being at least 15 mm. The first and second prongs diverge away from one another at an angle of less than 15 degrees. The first prong extends into the second bore of the first segment and the second prong extends into the first bore of the second segment. Mutually facing contact faces 46, 48 of the first and second prongs have profiles complementary to the radiused wall sections 30 of the bores.