Fluidized sand expansion joint

摘要

An expansion joint is provided between the bottom supported tube walls and the top supported tube walls of a fluidized bed boiler furnace. The expansion joint includes an upwardly open trough having one side and a floor defined by bent portions of the bottom supported tube wall, and another side wall defined by a refractory lined steel plate. A knife edge or sealing projection is connected to an outwardly bent portion of the top supported tube wall and extends downwardly through the upward opening of the trough and into the spaced defined by the trough. The trough is filled with sand or other inert granular material which partially covers the knife edge. The knife edge is in the form of a tube wall with tubes having lower perforations. Fluidizing gas can be supplied into the knife edge to fluidize the sand around the lower end of the knife edge to permit movement of the knife edge in the sand as the top and bottom supported tube walls expand. A satisfactory seal is provided by maintaining a suitable height of the sand covering the knife edge.