Abstract: An improved process of curing resin-bonded refractory brick lining of a ladle within a housing by heating the brick in air at an effective temperature to produce resin vapors and transferring the vapors from the ladle comprising transferring the vapors at a temperature above the condensation temperature of the transferred vapors to an auxiliary burner to effect combustion of the transferred vapors to produce non-toxic gases. The process provides an efficacious and environmentally sound treatment of resin-bonded refractory bricks.

Abstract: A heat exchanger for heating air supplied to a burner is described. The heat exchanger includes two passages. One of the passages provides a channel through which combustion gas is exhausted from the burner while the other passage provides a channel through which air is supplied to the burner. The two passages are arranged to transfer heat from the combustion gas to the combustion air. Each of the passages includes a helical guide baffle for directing fluid through each respective passage substantially along a helical flow path. The helical guide baffles of the passages each exhibits a variable pitch which changes at a predetermined rate to maintain the pressure and velocity of the fluid in the respective passages within predetermined limits.