Patent GB-967271-A (GB)
Title: Improvements in or relating to charging apparatus for shaft furnaces
Inventor: HOLMES FRANK RICHMOND
IPC: C21B7/18
Filed: 1960-10-01
Abstract: 967, 271. Weighing apparatus. ASHMORE, BENSON, PEASE & CO. Ltd. Sept. 26, 1961 [Oct. 1, 1960], No. 33756/60. Heading G1W. Charging apparatus for a blast furnace equipped with a skip hoist comprises a plurality of bins, one each for ore or other material, means for automatically feeding to the skip predetermined charges of coke and water and of at least two other materials, e.g. iron and limestone, programme control means for rendering all charge feeding means individually operative singly or in combination in a preselected sequence, delivery means for withdrawing ore or other material from the bins responsive to said control means and responsive to weighing means associated with and individual to each bin, each weighing means comprising a continuously movable conveyer for receiving material from a delivery means and weightresponsive means carrying at least a part of the conveyer, means responsive to the speed of the conveyer, and switching means responsive to the weight and speed for providing a delivery means stopping signal when a predetermined quantity of material has been passed. The control means includes a step by step switch having a plurality of positions, each position corresponding to one sequence in a charging programme, a plurality of manually operable switch means, each associated with an individual position of the step by step switch means and with one sequence in the charging programme for preselecting the nature of the charge to be fed during that sequence and drive means for advancing the step by step switch means from one position to another in timed relationship with charge feeding operations. General description Fig. 3, which diagrammatically and generally illustrates a first embodiment of the invention, shows the upper part 67 of a blast furnace which includes a distributer 68 rotated by a driving mechanism 69, a small bell 70 and a large bell 73. A double skip hoist is used, the two skips 23, 21 being referred to, for convenience, as north and south, similar references being made to the components associated with the north and south skips, such as storage bins, weigh hoppers and feeders. Water may be added to the skips through pipes 144, 147. The control system can be sub-divided into a number of units, including a north material programme control as delineated by a block 87, a north coke charging control delineated by a block 88, a water charging control delineated by the block 89, a south coke charging control delineated by the block 90, a south material programme control delineated by the block 91, a distributer programme control delineated by the block 92, a step by step bell sequence switch 93, a step by step bell counting switch 94, a large bell control 96 and a small bell control 95. The material programme controls include step by step switches 97, 98. The bell sequence switch 93 has five positions, and is driven sequentially from one position to the next generally in response to completion of the operations which it initiates at each position, and thus serves to relate the operation of the bell counting switch 94, the north and south material programme controls 87 and 91, the north and south coke charging controls 88 and 90, the water charge control 89, the distributory control 92 with the distributer 68, the small bell 70 the large bell 73 and the skip hoist 84 into appropriate timed relationship with one another. The moving contacts of the bell sequence switch 93 are driven step by step by an electric motor 150. The moving contacts have five positions, and are always driven forward in the same direction so that the moving contacts are in the first, second, third, fourth, fifth positions and then re-engage the first position. The moving contacts of the bell counting switch 94 are driven step by step by an electric motor 151 and are always driven step by step in the same direction. At the start of the programme they are in the first position and are then driven step by step until they reach a position where switch C associated with that position has been operated to indicate the end of a programme, whereupon they are driven forwards in the same direction until they return to their first or starting position. The moving contacts of the north material programme switch are driven by an electric motor 152 which, unlike that driving a moving contact to the bell counting switch, is reversible. The moving contacts of the south material programme switch 98 are driven by an electric motor 153 which is reversible. In the case of those of the north and south material programme switches, the moving contacts at the beginning of a programme are in the first position and then are advanced step by step into the second and third and successive positions until they reach a position at which the switch C associated with that position has been operated to indicate the end of the programme whereupon they are driven in the reverse direction back to the first or starting position. There is a number of selector switches for each sequence in the programme. For each sequence one switch, A, can be pre-set to select either an automatic coke charge, or an automatic material charge, or a manual material charge. A second switch B, can be pre-set to determine whether the large bell should be opened to dump charges into the furnace after the small bell has been opened to dump that charge on to the large bell. A third switch C can be pre-set to indicate whether or not that sequence shall determine the end of the programme. A fourth switch D can be pre-set to determine from which bins material shall be drawn if an automatic material charge is called for in the sequence to which it relates. Intermediate limit switches in the check weighing mechanism divide the range into zones, and for each sequence in the programme a switch E is provided for preselecting the appropriate weight zone and conditioning a check weight relay. The various feed conveyers are driven by motors, pilot lights indicating when they are running up to speed. An example is described in which a sequence of eight charges is operated. The first sequence is to be a charge of coke delivered by the north skip and a switch A1 is therefore operated into the position corresponding to a coke charge. This switch A1 has contacts associated with the bell counting switch 94 and with the north material programme switch 97. The second sequence is to be a charge of coke delivered to the south skip and a switch A2 is therefore operated with the position corresponding to a coke charge. This switch also has contacts in the bell counting switch 94 and also associated with the south material programme switch 98. The third sequence is a charge of ore from number one north material bin and switch A3 having contacts associated with the switch 94 and also with the north material programme switch 97, is operated. The fourth sequence is a charge of ore and limestone from the number one south material bin and number six south material bin and the switch A associated with the fourth sequence will be operated, this switch having contacts associated with the switch 94 and with the south programme switch 98. In addition, the switch D which comprises a plurality of switches each individual to a separate material bin will be operated to correspond with No. 1 south material and No. 6 material bin. As the large bell is to dump following on the opening of the small bell in the fourth sequence of the programme, switch B associated with this sequence and denoted B4 will be operated to correspond to a large bell dump. Similarly switches A5, A6, A7 and A8 are operated appropriately and switches D7 and D8 likewise. To cause the programme to end after the eighth sequence the switch C8 is operated. Odd sequences are concerned with the north skip and even sequences with the south skip: Initially an automatic coke charge selector relay 170 is operated and, in co-operation with a limit switch 85, causes discharge of coke from a check weigh hopper 24 until the operation of a limit switch 127. If a selector switch in the water charge control 89 has been operated for the addition of water a valve 142 is opened for a predetermined time. Following the closing of the water valve and hopper gate, the bell sequence switch 93 is advanced to its second position and the north skip hoist 84 is started. Operation of the limit switch causes a distributer control 92 to rotate the distributer 68 through a predetermined angle and the bell sequence switch 93 is moved to its third position. Consequently the small bell 70 is opened and the small bell control then sends signals which move the bell sequence switch 93 into its fourth position and the bell counting switch to its second position. A small bell operator 74 is then operated to close the small bell, on which the bell sequence switch 93 is advanced to its fifth position, at which an interlock signal enables the hoisting of the skip hoist 84 to be completed. The level of the burden in the blast furnace is checked by stock lines 78, 81 and if the level of the burden is appropriate to enable the large bell to be opened the stock line winches 79 and 82 are operated by the large bell control 96 to raise and withdraw stock lines. When the stock lines have been fully withdrawn, as determined by limit switches 80, 83, the large bell operator 71 is operated to lower and open the large bell 73. On completion of the skip hoisting a limit switch 81 is operated and the south coke control 90, in combination with the automatic coke charge selector relay 170, causes a charge of coke to be delivered into the south skip. Also the water control 89 opens a valve 145 to feed a charge of water into the skip. The sequence of operation of the bell sequence switch, the distributer, the bell counting switch, the bell counting relays, the small bell control and the large bell control is then repeated. The end of the second seq