Patent GB-281002-A (GB)
Title: Improvements relating to regenerative gas-fired furnaces, more particularly of the open-hearth type
IPC: F27B3/20
Filed: 1926-08-23
Abstract: 281,002. Schucany, W. Aug. 23, 1926. Open-hearth furnaces. - A process of working a regenerative gas-fired furnace of the reversible open-hearth type is characterized by the gas and air streams issuing from the gas and air ports being heated to equal or predetermined different temperatures according to the calorific value of the gas by adjusting the outlet flue cross sections to vary the distribution of the waste gases over the regenerative chambers. The ratio of the cross sections of the gas and air supply ports and the inclination of their axes are so adjusted that combustion takes place on the surface of the bath of metal only, while the inclinations of the axes of the gas and air supply ports are continuously varied so that the flame sweeps to and fro over the whole or a portion of the surface of the bath of metal. As shown in Figs. 4 and 5, the ports in the burner heads are provided with water-cooled flaps 1 - - 4 pivoted at 6 and operated by means of arms 7 - - 10 arranged externally of the furnace and pivotally connected to nuts 27, 28, mounted on sleeves 15, 15', 16, 16<1> keyed to a shaft 14 and provided with right and left handed threads so that during the rotation of the shaft 14 the flaps 1, 2 for the air port and the flaps 3, 4 for the gas ports are caused to move towards or away from one another. The sleeves 15, 15<1> and 16, 16<1> are locked in position relatively to one another on the shaft 14 by adjustable bushes 17, 17<1> engaging with collars 26 formed integral with the shaft 14. The upper end of the shaft 14 is supported in a nut 29 adapted to be clamped in position when the shaft is being raised or lowered and released when the shaft has reached its limiting position. During the sweeping of the bath of metal bv the flame, the shaft 14 is raised and lowered and rotated to vary the opening of the flaps and the inclinations of their axes. The shaft 14 is driven through gearing 35 from a shaft 33, clutches 40, 41, 52, gearing 55, and reversible motor 123. The shaft 33 carries a runner 48 for operating the clutch-actuating rod 43 to reverse the direction of rotation of the shaft 33. Assuming that the clutch 41 is engaged, the runner 48 moves along the shaft 33 from right to left while the flame is travelling over the bath from left to right and the shaft 14 is being screwed down in the nut 29. When the runner 48 strikes the abutment 44, the clutch-operating mechanism reverses the shaft 33 and the shaft 14 is raised to cause the flame to sweep over the bath from right to left. The runner 48 then moves from left to right until it engages with a manually operated abutment 45 on the rod 43, whereupon the action is reversed. The to-and-fro play of the flame is repeated until a reversal of the burner to waste gas is required when the abutment 45 is turned out of the path of the runner 48, which then moves towards the abutment 102 on the rod 43 and reverses the clutch and at the same time engages with the rod 53 for actuating the clutch 52 and thus stopping rotation of the shaft 33. During the movement of the runner 48 between the abutments 45 and 102, the nut 29 is released from its clamping device so that it is merely screwed down on the shaft 14, which is prevented from rising further but continues to rotate to open the flaps to their waste gas position, which is effected when the runner 48 reaches the abutment 102 and disconnects the clutch 52. Simultaneously the flaps at the opposite end of the furnaces are actuated to cause the flame to sweep the bath from the opposite end. When it is desired to vary the ratio of the cross-sections of the fuel and air supply ports for a particular calorific value of gas, a shaft 34 carrying an indicator 71 moving over a scale showing the gas value is operated by the motor 123 to effect a pull on ropes 66 through which rods 58 are actuated to cause the engagement of toothed wheels 57 with toothed projections 61 on the bushes 17, 17<1>, The shaft 34 also operates the auxiliary shaft 18 and through clutches 19, 20 and the gearing 57, 107, 108 actuates the bushes 17, 17<1> to vary the position of the sleeves 15, 15<1>, 16, 16<1> and the opening of the flaps. The arms 9, 10 of the flaps 3, 4 are provided with flexible joints and stops are provided whereby the movement of these flaps may be limited.