Abstract: The present invention provides a radiant tube supporting apparatus for a radiant tube arranged as a radiant heat source in a heat treatment furnace. The radiant tube is inserted through a furnace wall on one side having a supporting member attached to a bend at the tip of the radiant tube. The supporting member projects to outside the furnace through the furnace wall on the other side, and a bearing member bearing the supporting member is provided outside the furnace.

Abstract: A continuous heat treating furnace in which heat is efficiently recovered from the combustion exhaust gas from the heating section of a continuous annealing furnace. The continuous annealing furnace of the metal strip is a heating furnace or a heating device provided with plural burners for heating to a predetermined temperature a steel material or a continuously supplied metal strip by means of combustion of the burners; a regenerative heat exchanger for collecting a sensible heat of a combustion exhaust gas of the burners, reserving the heat in a regenerator and supplying a predetermined gas to the regenerator to recover the heat to the predetermined gas; and a preheating section for blowing the predetermined gas from the regenerative heat exchanger to the metal strip for preheating. The heat exchanger body is divided into at least three sections, each section having a regenerator.