| 摘要 |
PURPOSE:To assure the top and bottom surface temps. in the stage of discharging a material to be heated at prescribed values by setting the furnace temps. in upper and lower parts at which the material is heated from the upper and lower parts with good accuracy with a computer. CONSTITUTION:An arithmetic device 10 for slab temp. calculates the average temp. thetaM(t0) of an object slab at the present time t0 according to, for example, a start signal G in the stage of heating the slab 1. The set value thetag.u of the furnace temp. in the upper part is determined from said average temp., as well as the target discharge temp. thetaM.REF and presscribed difference DELTAthetaS.REF between upper and lower surface temps. applied from the outside with an arithmetic device 21 for said set value by the equation I [c: specific heat (Kcal/kg deg.C), rho: density (kg/m<3>), DELTAt: a specified time, k1: k2 the constant determined by the kind and average temp. of the slab, sigma: Stefan-Boltzmann constant, epsilon: radiation rate]. As a result, an upper burner 41 is controlled with a control device 31 for the furnace temp. in the upper part so that the value of a sensor 51 for the furnace temp. in the upper part attains said value. The furnace temp. in the lower part is similarly set by determining the set value thetag.l of the furnace temp. in the lower part by the equation II in the same way and controlling a lower burner 42 so that the value of a sensor 52 for the furnace temp. in the lower part attains said value. |
