Abstract: In a percussive rock bit or similar tool wherein cemented carbide cutting inserts are retained in open radial slots in the head of the tool, an improved method of mechanically retaining the inserts. The inserts are provided with a plurality of elongated radially aligned serrulations along each flank thereof, the thickness of the insert as measured between the crests of opposing serrulations being such as to provide a substantial interference with the slot wall. The inserts may be cold fitted by sliding along the slot, following which body material is peened so as to overlay a small chamfer at the base of the outwardly facing wall of the inserts. The inwardly facing walls of the inserts may be inclined so as to retain the center plug of the rock bit mechanically.

Abstract: An absorber tower maintenance isolation system for isolating an absorber tower while maintaining a steam generation plant in operation. An inlet blank-off plate and outlet blank-off plate cooperate with louver dampers in the inlet and outlet ducts to permit shut down or start up of an absorber tower. Closure devices and locking devices act to keep the blank-off plates in position. Equalization devices and duct vent holes allow release to the atmosphere. Further, access is provided to the absorber tower inlet and outlet ducts.

Abstract: An absorber tower maintenance isolation system for isolating an absorber tower while maintaining a steam generation plant in operation. An inlet blank-off plate and outlet blank-off plate cooperate with louver dampers in the inlet and outlet ducts to permit shut down or start up of an absorber tower. Closure devices and locking devices act to keep the blank-off plates in position. Equalization devices and duct vent holes allow release to the atmosphere. Further, access is provided to the absorber tower inlet and outlet ducts.