Keystone set

摘要

The keystone set, for a refractory brick vault, consists of a mortared assembly of a keystone (4) between two adapter bricks (3) which interlock with adjoining refractory bricks (1). The keystone and the adapter bricks are magnesia bricks. In the assembled state, the joint faces (5) are flat faces with matching grooves (6) forming open-ended channels (7) for insertion of solid coupling rods (8) of plain carbon steel.