AIR RATIO REGULATING METHOD FOR FURNACE EMPLOYING HEAT ACCUMULATION TYPE BURNER

摘要

PURPOSE:To stabilize an oxygen concentration in a furnace at sufficiently low value in the case of switching the combustion and opening the furnace door by a method wherein the flow rate of fuel the flow ratea of combustion air are fixed to values immediately before switching combustion in a specified period of time from the starting of switching of combustion in a direct firing type heating furnace employing a heat accumulation type burner. CONSTITUTION:An oxygen concentration detector is installed in the exhaust gas inducing system of a direct firing type heating furnace employing a heat accumulation type burner. The increase and decrease of the slow rate of combustion air is controlled automatically by an ratio controller with respect to the flow rate of fuel, which is determined and commanded from the combustion load in the objective zone of control, so that a signal from the detector is converged to a set value. In this case, the flow rate of fuel and the flow rate of combustion air are fixed to values immediately before the switching of combustion within an eapecially set peried of time T from the starting of switching of combustion. In this case, the set time T means a period of time expressed by the formula of (time requested for the opening and/or closing of a switching valve) + (total sum of the volumes of a heat accumulating chamber 22 and a gap 23 in a burner tile of heat accumulation type burner in the objective zone of control)/(speed of exhaust gas in the objective zone of control).