Patent GB-581585-A (GB)
Title: Improvements in electrical control arrangements for flame cutting devices
IPC: B23K7/06
Filed: 1944-06-30
Abstract: 581,585. Removing surface metal by blow pipes. LINDE AIR PRODUCTS CO. June 30, 1944, No. 12443. Convention date, July 14, 1943. -[Class 83 (iv)] Rolling-mill plant; roller tables.-An apparatus for flame machining, desurfacing, or cutting a steel bar, billet, bloom, slab, &c., is automatically controlled electrically upon manual initiation, the apparatus comprising an automatic timing device, a manually-operated switch for activating circuits to effect the flow of preheating gases to one or more blow-pipe heads, to move the heads into operating position &c., to set off the timing device, a first relay responsive to an electrical impulse for starting a flow of water over the body to remove slag, and a second relay responsive to an electrical impulse for starting a flow of oxidising gas to the blowpipes, and for starting relative movement between the blowpipes and work, the timer delivering an electrical impulse at predetermined time intervals to each of the relays. The machine A, which is of the kind described in Specification 553,337, and is mounted on a motor-driven carriage W on rails R for transverse movement into and out of alignment with a roll table conveyor C, has floatingly mounted desurfacing units E, F, provided respectively with nozzles 22, 28 for acting on the horizontal surfaces of the slab &c. and nozzles 23, 29 for acting on the vertical surfaces, the unit E being moved vertically upwards and the unit F vertically downwards to operating position and the nozzles 23, 24 being further separately movable horizontal for this purpose. the rolling mill comprises several roll-table motors for feeding the slab past or through the machine, a pinch roll being preferably provided to increase positive movement. A roll table master switch is first operated so that the machine may be brought over the roll table. The desurfacing operation is started by depressing a push button switch 36, which is held down during the complete cycle of operations. This energizes a relay C2 to operate a switch 37, which by opening contact 38 keeps the carriage motor out of operation, by closing contact 39 relieves the roll-table motor from control by the mill master switch and also by contacts 41, 43, closes one of the contacts of the table motor and energizes the timing device 44. At the same time, by closing contact 44a a relay C3 is energized to close a switch 49, which by opening contact 45 causes valves 51a, 51b to open to condition the units E, F for subsequent movement towards the work. Closure of contact 47 controls valves 55, 56, 57 which causes the movement of the units E, F to embrace the work, and valves 57a and 57b which turn on the preheating acetylene and oxygen in the blowpipes. Closure of contact 48 causes pinch roll to be applied to the work. When large slabs are being operated on, the preheating gases for further blowpipe nozzles may be put in operation at this time by opening valves 52a, 53 on closure of contact 46. These circuits may be put out of action when desired by a manually-operated snap switch 55a or by automatically operating guide limit switches. A hydraulically-operated pressure switch 58 is provided in the circuit of the valves 57a and 57b so that if the necessary water pressure for cooling the blowpipe heads is absent, the preheating gases are turned off. The preheating units may be tested by pressing a switch 60, in a circuit which directly energizes relay C3. The electrical timing device 44, which is adjustable, in addition to the normal circuit through wire 62b is provided with a wire 62a containing a time delay push button 63 and clutch so that by depressing the button the movement of part thereof may be stopped without opening any of the circuits previously closed by the timer so as to permit lengthening of any particular timing interval at the discretion of the operator. A mechanical or electronic timer may be used, if desired. At the end of the first timing interval relay AC1 is energized and in addition to closing of contact 64, which connects with the roll table motor, closes contact 65 to operate valve 66 for turning on the slag removing water and also a valve 67 which causes the units E, F to press against the slabs at a lower oil pressure. The timer then causes operation of relay AC2 whereupon,contact 68 is closed to operate valves 72, 73 to supply cutting oxygen to the units E, F, and also, when required, the valve 54 for supplying cutting oxygen to the additional nozzles. A push button 74 is provided to shunt the relay AC2 for testing or purging the cutting oxygen delivering units. Closing of contact 69 closes circuit through the line running to the rolltable motor, and closing of contact 70 causes operation of the table motor to feed the slab through the machine to complete the desurfacing operation. After an interval long enough for the slabs to enter the rolls of a mill stand, situated beyond the machine, the relay AC3 is energized to open contacts 75, 76 so as to raise the pinch roll and open the mill table motor circuit and restore control of the roll table motor to the mill master switch. Restoration of the roll table motor in this manner permits the operator to reverse or advance the roll table to bring in another slab or prevent a following slab from hitting into the machine concurrently with the desurfacing operation. The contact 76 and its circuits may be dispensed with in which case the positive driving of the rolls of the roll table will be continued until the slab-is advanced through the machine. When the trailing end of the slab approaches the blowpipes the push button 36 is released to reset the machine. U.S.A. Specification 2,244,822, is also referred to.