PURPOSE: To simply remove soot even during operation by inserting a high air ratio combustion torch having the specific excess air ratio into a radiant tube clogged with the soot in the inner part and blowing combustion flame to the soot.
CONSTITUTION: In the inner part of the radiant tube 1 set in a heat treatment furnace 9, the combustion of the burner 2 is executed, and the tube 1 is red- heated to heat a steel sheet. Then, in the case incomplete combustion happens because of shortage of the air for combustion in the burner 2 or in the case mixture becomes bad because of breakage of a burner nozzle 3, the soot 10 is stuck and piled in the inner part of the tube 1, and the inner part of the tube 1 is perfectly clogged very often. Then the torch 14 is inserted from an opening hole 11 at the inner part of the burner 2 and the high air ratio flame having ≥1.5 the excess ratio is brought into contact with the soot 10 from this tip part 6, burnt and removed. In the case the air ratio is ≤1.5, the combustion does not continue. Then the temp. of the soot becomes ≥600°C very often, but in this case, by inject-ing only the air from the torch 14, the soot can be burnt and removed.
OHASHI TOSHIHARU
OKOCHI TOSHIHIRO
