Immersion-type burner heater and molten-metal holding furnace
An immersion-type burner heater includes a heater protection tube that is installed so as to penetrate a furnace wall or an upper lid of the molten-metal holding furnace with the tip end thereof being closed; an inner cylindrical member arranged inside the tube so as to define a combustion flow passage S between the tube and itself with the tip end side thereof being open and the inside thereof serving as an exhaust gas flow passage; and a gas burner part supplying fuel gas and air to the combustion flow passage. A helically extending projecting part is provided on at least one of the outer peripheral surface of the member and the inner peripheral surface of the tube at a position that is closer to its tip end side than to the part penetrating the furnace wall or the upper lid.
1. An immersion-type burner heater, comprising:
a heater protection tube installed so as to penetrate a furnace wall or an upper lid of a molten-metal holding furnace with a tip end thereof being closed;
an inner cylindrical member arranged inside the heater protection tube so as to define a combustion flow passage between the heater protection tube and itself with the tip end side thereof being open and the inside thereof serving as an exhaust gas flow passage;
a gas burner part supplying fuel gas and air to the combustion flow passage; and
a helically extending projecting part provided on an outer peripheral surface of the inner cylindrical member at a position that is closer to the tip end side of the inner cylindrical member than to a part penetrating the furnace wall or the upper lid; and
a heat insulating member made of a heat insulating material having a lower heat conductivity than the heater protection tube and provided on a part of the outer peripheral surface of the inner cylindrical member where the projecting part is provided.
2. The immersion-type burner heater according to claim 1 , wherein the projecting part is provided on an outer peripheral surface of the heat insulating member.
3. The immersion-type burner heater according to claim 1 , wherein the projecting part is a helical fin that is provided on the outer peripheral surface of the inner cylindrical member.
4. The immersion-type burner heater according to claim 1 , further comprising:
an air flow passage supplying air into the combustion flow passage at the part penetrating the furnace wall or the upper lid; and
a heat exchange fin that is fixed on the inner cylindrical member or the heater protection tube, the heat exchange fin being provided in the air flow passage.
5. The immersion-type burner heater according to claim 1 , wherein
the heat insulating member is provided on an outer peripheral part of a base end side of the inner cylindrical member.
6. The immersion-type burner heater according to claim 1 , wherein
the heat insulating member is provided on the inner cylindrical member over a range from its base end side to a vicinity of its tip end.
7. A molten-metal holding furnace, comprising:
a holding tank holding molten metal; and
an immersion-type burner heater according to claim 1 that is installed so as to penetrate a furnace wall or an upper lid of the holding tank.