GB502942A - Improvements in blast furnaces - Google Patents

Abstract

502,942. Electrically -actuated valves. FREYN ENGINEERING CO. Aug. 26, 1938, Nos. 25103 and 25104. Convention dates, Aug. 27, 1937 and Aug. 17, 1938. [Class 135] [Also in Group XII] A charging hopper for blast furnaces having lower and upper bells 11, 12 is provided with a valve controlled pipe 25 to equalize the pressure between the furnace and the hopper to allow the lower bell to be readily opened. As shown in Fig. 1 the bells 11, 12 are actuated by hydraulic hoists 16, 22 having control valves 17, 23 actuated by electric motors 18, 24. The valve 26 in the pipe 25 is actuated by an electric motor 28, through a segment 27, which carries abutments 37, 38, Fig. 3, adapted to engage with limit switches 39, 40, 41, 42. Switch 39 is biased to open and is closed when the valve 26 is open; switch 40 is biassed to open and is closed when the valve 26 is closed ; switch 41 is biassed to close and is open when the valve 26 is open; switch 42 is biassed to close and is open when the valve 26 is open. The switch 40 is in the circuit of motor 24 so that the hoist 22 cannot be actuated by pressing the push button 46 to open the bell 12 unless the switch 40 and the valve 26 are .closed. Similarly the switch 39 is in the circuit of the motor 18 and the hoist 16 cannot be actuated to open the bell 11 by pressing the push button 44 unless the switch 39 is closed and the valve 26 is open. When the bell 12 is closed, a contact 36 is closed and opened again when the bell is opened. The electric circuit for the motor 28 is shown in Fig. 2. When it is desired to open the bell 11, push button contact 31a is closed and since the switches 36, 41 are closed, the coil 33b is energized to close switch 33a. Coil 35b is then energized to close switch 35a and field coil 28c of motor 28 is also energized, current flows to the motor armature 28a and the motor 28 is actuated to open the valve 26. The switch 39 being now closed, by operating push button 44 bell 11 may be lowered. After closing the bell 11 in the usual way, push button contact 32a is closed and, since the switch 42 is also closed, the coils 34b, 35b are energized to close switches. 34a, 35a and actuate the motor 28 to close the valve 26 after which by pushing the button 46 the bell 12 may be actuated. In a modification the hopper may be put into communication with an uptake leading from the furnace to the atmosphere, the communicating pipe being provided with a valve actuated as described above. Fig. 6 shows a further modification in which the hopper is in communication with the uptake 45 through a pipe 46 provided with a valve 58, Fig. 7, having one branch connected to the uptake 45 and the other connected to a pipe 59 leading to the atmosphere. The pipes 46, 59 are controlled by two counterweighed valves 63, 64 pivoted at 66 and operated by the cable 70 and motive mechanism 71. The top of the pipe 59 is providedwith a pressure relieving valve 60.