Patent GB-625380-A (GB)
Title: Apparatus for punching tuyeres of copper converters and the like
IPC: C21C5/48
Filed: 1947-07-25
Abstract: 625,380. Cleaning blast tuyeres. TRIGGS, W. W. (Kennecott Copper Corporation). July 25, 1947, No. 20138. [Class 72] [Also in Group XXVIII] An apparatus for punching out and removing slag from the tuyeres of rotatable converters used in the production of copper comprises a punching tool secured to the air supply housing of the tuyere and provided with a punch rod having independent supporting means and power means for rapidly reciprocating the punch rod longitudinally of the tuyere. The converter 1 having rings 2 riding on rollers 3 has a charging opening 7 and the refractory lining 6 and the tuyeres 19 are supplied with blowing air from a longitudinal pipe 8 having flexible connections 9, leading through passages 21, in housings 10 to the tuyeres. A ballvalve 27 prevents escape of air during the attachment of the punching device which causes the displacement of the ball to the Fig. 4 position. An adjustable stirrup 51 pivoted to the housing has a cross-piece 50 coacting with a nut 46 to secure the punching mechanism in position. The punch 36 is secured at 35 to the piston rod 34 of the pneumatic cylinder 15 the piston having conically recessed ends 42a, 42b, coacting with complementary formations on the cylinder covers to produce cushioning at the ends of the stroke and assist in the quick reversal of the punch. High pressure air at about 70 lbs. per square inch from the chest 53 is controlled by D slide valves 54a, 54b, operated by a yoke 58 from a handle 60. When the slide valves are moved to the right from the Fig. 4 position air is admitted to the left-hand end of the cylinder. This produces the punching stroke which terminates when the punch head has passed into the converter interior, Fig. 4. At the end of the stroke a port is covered by the piston skirt to produce cushioning and assist quick reversal of the punch, the return of the handle to the Fig. 4 position for the return stroke being assisted by the chest pressure on rod 59. In a modification, automatic means may be provided for reversing the punch movement. The valve members 79, 80, Fig. 10, are actuated by a stem 84 mounted in the valve chest and engageable by a lever 87 A differential cylinder 90 with piston portions 91a, 91b is located within the valve chest. When forward pressure is applied to handle 87 the valve stem is moved to the Fig. 10 position, moving the piston 73 on the punching stroke. Continued forward movement of the handle causes the latter to disengage the stem 84, and when ports 93a are uncovered by the piston 73 in its forward travel pressure builds up on the differential piston 91a and so reverses the slide valve 78 and returns the punch piston. The punch assembly is of such dimensions that it may remain in position at different rotary adjustments of the converter. As the refractory lining of the converter wears, progressively shorter punch rods are employed so as to limit the penetration of the punch tip into the molten charge and the punch velocity for the operative part of the travel is about 20 feet per second. During the punching stroke whipping action of the punch occurs owing to the unbalance of the operating means and the flexibility of the mounting. In this way the punch clears an opening larger than the punch tip.