Burner with recuperative air preheating and thermal insulation between the recuperator and the external cap of the burner

A burner suitable for heating a furnace chamber for an industrial process and comprising a tubular recuperative preheater of combustion air having at least an outer annular channel for removal of combustion product gases, a combustion chamber at one end of said burner, for heating a furnace, and a feed-through burner cap located at the other end of said burner for access to said burner outside and said furnace and having means through which fuel and combustion can be controllably supplied to said burner, said combustion chamber, tubular recuperative preheater and burner cap being substantially aligned on a central axis of said burner and said tubular recuperative preheater being in fixed spatial position relative to said burner cap for supporting said burner cap outside of said furnace and having, at its end which is opposite said combustion chamber, an outflow collector cap connected to an outflow pipe for combustion product gases, said tubular recuperative preheater also being connected for axially countercurrent flow of combustion air supply to said combustion chamber and combustion product gas from said combustion chamber in respective channels which are thermally coupled to each other for heat transfer, comprising:

• a fuel supply pipe coaxial with said central axis and extending from said feed-through burner cap to said combustion chamber and
• a spacer sleeve (29) of a material having small heat conductivity located in the region between said outflow collector cap of said tubular recuperative preheater and said feed-through burner cap and mounted on said burner cap and said tubular recuperative preheater for maintaining the relative positions of said burner cap and said tubular recuperative preheater, whereby said burner cap is thermally isolated from hot parts of said burner.