PURPOSE: To maximize the thermal efficiency of a single type annealing furnace by determining the rising pattern of representative furnace temps. as a function of a combustion time and the coldest point temp. of materials to be annealed as a relation of furnace temps. beforehand respectively, and controlling the min. point temp. successively toward a target value.
CONSTITUTION: The rising pattern of a representative furnace temp., for example, a temp. Tx of circulating gaseous flow is determined as a function Tx(t) of a combustion time t, and the temp. To at the coldest point of materials to be annealed is beforehand determined as a function To(Tx) of Tx. The time t for the purpose of obtaining the prescribed coldest point temps. after the actually measured value of the temp. Tx at a certain point of time is assumed and the time (t±Δt) obtd. by adding or subtracting the deviation Δt to or from said time t is determined. Within the range of said times (t-Δt)W(t+Δt), the transformation of the function To(Tx) to an inverse function is easily approximated and in accordance with said approximate function, the temp. Tx for the purpose of obtaining a desired temp. To is determined. In accordance with said temp. Tx, the time to for obtaining the temp. To is determined.
OOTSUKA MASANOBU
MAKINO TADASHI
