| 摘要 |
987,361. Hot blast stoves. HEINRICH KOPPERS G.m.b.H. Feb. 7, 1963 [Feb. 16, 1962], No. 4979/63. Heading F4K. [Also in Division G3] In a hot blast stove assembly in which each stove is cycled between "on-blast" and "ongas" steps, a control system adapted to compare the actual duration of one step with a preset desired duration thereof is provided to control the heat generated during the next "ongas" step, the heat being increased if the actual duration is less than said desired duration and vice versa. As shown, an assembly comprising two hot-blast stoves 1 and 2 with burners 3 has a cold air conduit 6, which supplies air to the stoves through valves 7a and inlets 7, valve-controlled combustion gas conduits 4 to the burners, hot-blast supply lines 8 and valves 30 controlling the outlets for exhaust combustion gases. The temperature of the hot blast leaving the assembly is maintained constant by introducing controlled amounts of cold air from line 6 through a by-pass line 12 to the line 8 at point 13. A temperature-sensitive device 31 downstream of the latter point controls a regulating device 15 on which the desired temperature is set by a manual control 16, the device 15 in turn controlling a valve 14 regulating the amount of air supplied through line 12. The " on-blast " step of a stove is terminated when the temperature of the hot blast upstream of point 13 falls to a predetermined value as sensed by a device 20 which signals the end of the step to a device 21 which, in turn, compares the actual duration of such step with a pre-set desired duration and operates a valve 19 through a device 18 to vary the amount of gas supplied to the burner 3 during the next " ongas " step by a proportion equal and of reverse sign to the proportional difference between said actual and desired durations. The device 18 controlling the valve 19 is set by a manual control 17 to provide the correct amount of heat to maintain the desired duration of the " on-blast " step during normal operation, the calculating device being operable to correct for departures from said normal operation. The volume of the hot blast is controlled by valves 23 and 9 upstream and downstream respectively of the point at which line 12 is connected to line 6, said valves being controlled by a device 11 having a manually adjustable control 10. The temperature-sensitive device 20 may be replaced by a flow-sensitive device which signals the end of the " on-blast " step to the device 21 when the volume of air flowing through line 12 falls to a predetermined value. |
