US2752649A - Feed spout for continuous casting machine - Google Patents

Description

y 3, 1956 J. HUNTER 2,

FEED SPCUT FOR CONTINUOUS CASTING MACHINE Filed Dec. 27, 1952 3 Sheets-Sheet 1 H ummw ql/ 2" INVENTOR. /Z. l/u/vme BY/WE% y 3, 1956 J. HUNTER 2,752,649

FEED SPOUT FOR CONTINUOUS CASTING MACHINE Filed Dec. 27, '1952 3 Sheets-Sheet 2 a H Mil zwmmx (JOSE/W Z. l/uA/rm July 3, 1956 J. L. HUNTER FEED SPOUT FOR CONTINUOUS CASTING MACHINE mm m. 27. 1952 3 Sheets-Sheet 3 a 2 02 7/1 MM JNVENTOR. afasm llA umme United States 2,752,649 FEED sPoU'r non coNriNUoUs CASTING MAcHnsE Joseph L. Hunter, Riverside, Califi, assiguor to Hunter Douglas Corporation, Riverside, Calif., a corporation of Delaware Application December 27, 1952, Serial No. 328,205 1 Claim. (Cl. 22-5724) The present invention relates to a feed spout for continuous casting machine, and is a continuation-in-part of my co-pending application, Serial No. 162, 510, filed May 17, 1950, now Patent No. 2,631,343.

The type of continuous casting machine for which the feed spout of the present invention is intended is the chain mold machine, comprising a cooperating pair of endless chains of articulated, watercooled mold blocks that are mounted so that for a portion of their of the traveling mold through a spout of cross-sectional size and shape to fit closely within the mold cavity, and it is with this spout that the present invention is concerned.

stand erosion or dissolution in the metal. Among the few materials capable of withstanding the high temperature and also unaffected by contact with molten alumithe molten metal so up within the spout.

The primary object of the present invention is to provide a feed spout for chain mold casting machines, which is capable of conveying molten aluminum into the mold cavity without excessive loss of heat, and which is therefore free from trouble due to freeze-ups.

A further object of the invention is to provide a feed spout that is capable of withstanding the high temperatures to which it is exposed, and which is also unaffecte by contact with molten aluminum.

The foregoing and other ice Figure 4 is a top plan view of the machine with the spouts removed;

Figure 5 is an enlarged sectional view of taken along the line 5-5 in Figure 4;

Figure 6 is an enlarged, fragmentary sectional view taken at line 66 in Figure 5;

Figure 7 is a perspective View of the feed spout through which the molten metal is introduced into the mold cavi- 0;

Figure 8 is a transverse sectional view through the spout, taken at 88 in Figure 7; and

Figure 9 is a longitudinal horizontal section through the spout, taken at 99 in Figure 7.

Referring now to the drawings, the reference numeral 2% designates a melting furnace of the open hearth reverthe same,

31 enclosing the melting hearth, and

an external holding well 32 conder is admitted to the chambers.

The box 35 rests on The end of screw 46 bears against a protective metal plate 52 on the side of launder 34, clamping the latter tightly against the box 35, and holding the box against the ends of the spouts 36. The spouts 36 are themselves connected to a transversely extending, horizontal angle iron 53 (Figure 5) in a manner to be described in more detail hereinafter; the said angle iron 53 being welded or otherwise fixedly attached to the shelf 40.

Referring now to Figures 5 and 6, the casting machine 22 is seen to comprise a pair of endless chains of articulated, Water cooled mold blocks 6t), each of said chains being trained around horizontally spaced pairs of drive chains being disposed directly above the other and parallel thereto. The top chain of blocks is designated gen erally by the reference numeral 63, and the bottom chain J by the numeral 64. The two chains are driven in opposite directions by their respective drive sprockets 61, so that the bottom course of the top chain 63 and the top course of the bottom chain 64 travel together from left to right, as seen in Figure 5, and at the same rate of speed.

Each of the mold blocks is a massive block of hard, dense cast iron or steel, ground on all sides and in the machine as shown, having two shallow channels 65 and 65 (see Figures 2 and 3) formed in the outer face thereof. Each of the channels 65, 65' constitutes one half of the mold cavity for one of the bars of metal cast by the machine, and when the mating blocks of the adjacent courses of the top and bottom chains are brought together in proper registration with one another, they form a pair of laterally spaced, open end mold cavities of uniform cross section that extend longitudinally through the center of the machine. Transverse alignment of the mating mold blocks within extremely close tolerances is obtained by means of small rectangular end plates 67 which are secured by screws to opposite chain 63 and project outwardly for a short distance beyond the outer face of the block to form flanges that fit snugly down over the ends of the companionate block in the bottom chain 64. The bottom block is thus confined between the end plates 67, and is prevented thereby from shifting transversely with respect to the top block; hence the two blocks are always maintained in accurate transverse alignment with one another during the period of their conjunction.

Each of the mold blocks 60 is connected to the adjoining blocks by hinge pins which project laterally beyond the ends of the blocks, and journaled on the ends of the said pins are rollers 74 which run on the peripheral edges of rigidly supported side plates 75. Each of the side plates 75 is elongated horizontally, with straight top and bottom edges and semicircular ends having their centers of curvature at the axes of the sprockets 61 and 62. The side plates 75 of each chain 63, 64 are mounted on a supporting structure located at one side of the chain mold assembly, and are attached thereto by a pair of laterally spaced, thick-walled steel pipes 76 of large diameter which project horizontally outward from a side wall plate 79 of the supporting structure 80 between the sprockets 61 and 62. The structure 80 is made up of heavy steel plates Welded together at their edges to form a closed, box-like member of great strength and rigidity.

, The pipes 76 are closed at their outer ends, and are secured by bolts 81 to the supporting structure 80, the said bolts passing all the way through the supporting structure as shown in Figure 4.

The driving and driven sprockets 61 and 62 are welded or otherwise suitably fixed to drive shafts 85 and 35 between and immediately adjacent plates '75, the said shafts extending through circular openings in the plates. The outer end of the shaft 85 terminates in a threaded stud on which a nut 78 is screwed, and the latter is drawn up tight against a collar 77 that bears against the outside of the outer sprocket 61. Each of the sprockets 61, 62 is rotatably supported on the structure 80.

A spur gear is mounted on the end of the upper shaft 85 where it projects from the back of the supporting structure 8t), and is secured against rotation relative thereto by means of a key or the like. A corresponding spur gear is secured to the lower sprocket drive shaft. The top gear 95 is meshed with an idler gear 96, which is meshed, in turn, with another idler gear that is also meshed with the bottom spur gear and the last-named idler gear meshes with a pinion 98. Pinion 98 is driven by a sprocket 106 through a friction clutch 101, which is adapted to slip when overloaded, and thus protects the mold chains and driving mechanism from damage in the event that something becomes jammed.

Trained around the sprocket is a roller chain 110 which extends downwardly to and is trained around a ends of each block in the top sprocket 111 mounted on the drive shaft of an electric motor 112. motor shaft drives another chain 113 which is trained around a large sprocket 114 on shaft 115, to drive the pinch rolls 26. The electric motor 112 also drives the rotatable heads of the coolant distributor 24, and to this end, a sprocket 129 is mounted on the bottom drive shaft 35, which drives a chain 121 that is trained around another sprocket (not shown) on a shaft 123.

Shaft 123 extends structure 8%) (as shown in Figure 3) and is operatively connected to the coolant distributor mechanism 24 to drive the same. As described in detail in Patent No. 2,631,343, the coolant distributor 24 comprises a housing 125 which supports two vertically spaced, rotatable heads 134- and 135, that are driven from shaft 123 in the same direction and at the same rate of speed as their respective mold block chains 63 and 64. The heads 134, 135 are connected by flexible hoses 1'75 and 191 to inlet and outlet fittings on the ends of the mold blocks. A pump 164 driven by a motor 165 circulates coolant from a reservoir tank 170, through swiveled fluid couplings 160, heads 134 and 135, inlet hoses 175, mold block coolant passageways, return hoses 191, back into the tank 176, and out. through overflow pipe 172.

The feed spouts 36 through which molten metal is fed into the traveling mold assembly are shown in detail in Figures 7, 8, and 9. Each of the spouts comprises a centrally bored,'two-piece body of thermal-insulating refractory material enclosed within a rectangular, boxlike steel case 196. The refractory material of which the body 195 is made is preferably composed of diatomaceous earth and long-fibered asbestos, with an inorganic binder, such as sodium silicate. A small amount of time may be included in the mixture to combine with the sodium silicate and convert it into calcium silicate, which is more resistant to high temperature decomposition. The diatomaceous earth is substantially pure silica in microscopic cellular form, and combines high thermal insulating properties with complete inertness to molten aluminum. The asbestos fibers provide fibrous reinforcement for the material, and hold the cemented diatomaceous earth together.

The relative proportions of ingredients are not critical, though experimental results indicate that a superior product is obtained with the following proportions by weight: diatomaceous earth 30%, asbestos fiber 30%, sodium silicate (dry weight) 20%, and lime 20%. Increasing the percentage of diatomaceous earth produces a chalkier, product of reduced tensile strength, whereas an increase in the amount of asbestos fibers produces a fibrous product of reduced strength. A water solution of sodium silicate is used, and this is added to the dry ingredients to form a plastic mix, which is then molded and baked under moderate pressure.

Projecting from one end of the case is a tip 197 of the same material as the body 195, which is shaped to conform closely to the cross sectional contour of the mold cavity, but is provided with clearance on all sides to permit free movement of the mold blocks past the same. The length of the feed spout is governed by the position of the terminal end of the tip 197 within the mold cavity. In order to prevent molten metal from escaping through the crack between adjacent blocks as the latter come together after passing around the sprockets 62, it is necessary that the tip 197 project into the mold cavity to a point not less than 1 block width beyond the centerline of the sprockets 62.

The case 196 comprises side plates 198 to which top and bottom plates 199 and 200 are secured by countersunk screws 201. The top plate 199 is somewhat shorter than the bottom plate 200, and formed in the inner faces of the exposed end portions of the side plates 198 are vertically extending notches 202 which receive tongues 203 projecting laterally from opposite sides of the tip 197 at A second sprocket 116 (Figure 4) on theforwardly through the supporting greases the base end thereof. The tip 197 is thus keyed to the side plates of the case by a tongue and groove connection, and is conveniently inserted into the case or removed therefrom by merely slipping the back end of the tip down into the open notches 202. Metal cheeks or lands 204 are secured by screws to the outsides of the side plates 198 at the extreme ends thereof, and these are contoured to fit the sides of the mold cavity. The cheeks 204 provide solid backing for the extreme outer edges of the tip 197, and protect the latter against breakage or excessive abrasion in the event that the spout becomes slightly misalined within the mold cavity.

At the rear end of the case 196, the top, bottom, and side plates have vertical notches 205 formed therein to receive keys 206 that fit into notches in the inside faces of two laterally spaced blocks 210. The blocks 210 are welded or otherwise fixed to the top of angle iron 53, and are spaced apart just far enough to receive the rear end of the case between them. With the case thus keyed to the blocks 210, the spout is solidly held in place, and the box 35 can be clamped tightly against the rear ends of the two spouts, as described earlier.

The refractory body 195 of the feed spout is preferably made of two pieces for convenience in removing the solid plug of metal that freezes in the passages 211 each time that the machine is shut down. The passages 211 extend longitudinally through the body 195 from one end to the other, and may be drilled out, as shown in Figure 8, or formed in any other suitable manner. The rear end of the body 195 projects slightly beyond the end of the metal case 196, and terminates in a perfectly square, flat face 212 which abuts against the outside of the box 35, with the passages 211 registered with openings 213 (Figure in the box, through which the molten metal flows from the box into the spout.

The extreme outer end of the tip 197 is preferably formed as shown in Figure 9, with a center face 214 perpendicular to the axis of the spout, and two outwardly facing, slightly concave faces 215 that are swept back at an angle of about 35 to the face 214. Three outwardly diverging passages 216 are formed in the tip; one going to each of the three angularly related faces. The purpose of this tip configuration is to promote freezing of the metal at the sides of the mold first, so that the shrinkage cavity that tends to form in the cast bar as the metal solidifies and cools can be fed and filled by molten metal issuing from the center passage 216. The water-cooled mold blocks chill the metal so suddenly that freezing of the molten metal occurs almost instantaneously, and the bars are probably solid all the way through, although somewhat mushy in character, within a very short distance from the tip. The progressive freezing of the bars from the sides in toward the center that is obtained with the tip just described, enables the fluid metal discharged from the middle passage to keep full the shrinkage cavity that would otherwise be likely to form, until the center of the bar finally solidifies, and as a result the bars produced by the machine are sound and entirely free of shrinkage pipes and porosity.

One highly important feature of the invention has to do with the manner whereby the tip 197 acts to seal the back end of the mold cavity against leakage of molten metal. As mentioned earlier, the tip 197 is shaped to conform closely to the cross sectional contour of the mold cavity, and is provided with clearance on all sides to permit free movement of the mold blocks past the tip. This clearance may range from a few thousandths of an inch up to or more, and the highly fluid, molten metal under a head of several inches in the box 35, has a tendency to flow into the same. However, the cold mold blocks extract heat so rapidly from the molten metal in the corner at the junction of the tip face with the block, that the metal is chilled locally and becomes viscous or slushy, with a thin skin formed on its surface which prevents penetration of the metal into the crevice between the tip 197 and the mold blocks.

As the mold blocks move away from the tip, the skin is ruptured, and fluid metal flows back into the corner, where it is again chilled and another skin formed on the surface. This process is repeated with great rapidity all of the time that the machine is in operation, producing a faintly rippled surface on the bars; each ripple being from 6 to ,4 inch in width. Thus, the combination of cold mold blocks and a feed spout tip that conforms closely on all sides to the cross sectional contour of the mold cavity, yet without being in actual contact therewith, provides an arrangement wherein ample clearances are provided between relatively moving parts, so that excessive wear of the tip and abrasion of the mold blocks is prevented, and at the same time, a sealing action is obtained that prevents the molten metal from flowing into the clearances.

On leaving the machine at the exit end thereof, the bars of metal are guided laterally into the pinch rolls 26 between outer rollers 220 and tandem inner rollers 221 (Figure 4) which are rotatably supported on a horizontal shelf 222 projecting laterally from the supporting structure 80. The pinch rolls 26 comprise an upper, water cooled roll 223 and a lower, water cooled roll 224 which extend transverse to the direction of travel of the cast bars, and which are rotatably supported at their ends in bearing blocks 225. The bearing blocks 225 are slidable vertically between laterally spaced pairs of guide posts 226, which are mounted on a horizontal shelf plate 230 projecting laterally from the side of the supporting struc ture 80, the top ends of each pair of posts being connected together by a bridge member 231. An adjusting screw 233 is threaded downwardly through the bridge member 231 and engages the top bearing block 225 to adjust the spacing between the rolls 223, 224.

The bottom roll 22d is connected at its back end to the sprocket shaft 115 and is driven thereby in the clockwise direction, as viewed in Figure 5; the top roll 223 being driven by the bottom roll in the opposite direction and at the same rate of speed through a pair of intermeshed gears (not shown) which are enclosed within a housing 234 (Figures 3 and 4).

As the bars leave the pinch rolls, they are engaged on their outer edges by two guide rolls 250 (Figures 3 and 4) which are supported on a narrow shelf 251 projecting laterally outward from the supporting structure at the extreme end thereof.

Beyond the guide rolls 250, the bars pass through the flying shear cut-off 28, where they are automatically cut to predetermined lengths while continuing in motion. The flying shear cut-off (best shown in Figure 3) is essentially a hydraulically operated shear mounted on a freely movable carriage that is adapted to travel with the bars While the latter are engaged by the shear blades. The structural details and operation of the flying shear cut-01f 2s are fully described in my Patent No. 2,631,343, to which reference may be had, and since they form no part of the present invention, and will not be further described herein. The holding oven 30 likewise forms no part of the present invention, and is merely included in the drawings for the purpose of showing a complete machine.

The operation of the casting machine is believed to be self-evident from the foregoing description. When the machine is first started up, the openings 213 in the box 35' through which molten metal flows into the spouts 36 of the box, running down a gutter 204 into pig molds, until the launders 34 and box 35 have been thoroughly heated and the temperature of the metal in the box is right for casting. The passages 213 are then uncovered, and metal is allowed to flow through the spouts 36 into the mold cavities. The mold cavities are usually plugged with a block so as to prevent the metal from flowing along the mold cavity until the latter has been filled. These blocks are carried through the machine on the front ends of the bars, and drop off when the bars push out of the machine at the exit end thereof. While the speed of the machine depends upon a number of variables, I have found that the most satisfactory operation for aluminum alloys is obtained with a chain speed of approximately 5 feet per minute.

When the machine is to be stopped, the tap hole 33 of the furnace is plugged, and when the chambers 42, 43 have emptied, the keys 296 are pulled out, releasing the spouts 36 so that they can travel through the machine with the now-solidified bars. The tips 197 are usually destroyed in the process, but-these are inexpensive and are considered expendable.

While I have shown and described in considerable detail the presently preferred form of my invention, it will be understood that the description herein is merely illustrative, and that various changes may be made in the parts and components of the machine and in their arrangement relative to each other without departing from the broad scope of the invention as defined in the appended claim.

I claim:

In a continuous casting machine, a spout for delivering molten metal to a mold cavity, comprising a body portion and a tip portion, both of fiber-reinforced, cemented siliceous material, said tip portionhaving a cross-sectionalsize and shape such as to fit snugly within said mold cavity and having at its end a center dicular to the axis of the mold cavity and side faces swept back therefrom at an angle, the body portion of said spout a main molten metal passage extending being formed with longitudinally therethrough and the tip portion .of said spout being formed with a plurality of branch molten metal passages communicating with-said mainpassage and opening to the mold cavity one at each of said faces respectively said swept-back sidesvand branch passages of said spout admitting molten metal to the sides of said mold cavity before the center is filled,wl1ereby the metal is caused to freeze progressively from the sides of the mold cavity in toward the center-thereof and fluid metal discharged from the middle passagetends to fill any shrinkage resulting from freezing of the metal.

References Cited in the file of this patent UNlTED STATES PATENTS 377,343 Wendell Jan. 31, 1888 560,661 Trotz Q May 26, 1896 1,139,885 Mellen u May 18, 1915 1,338,001 Cordes Apr. 27, 1920 1,435,416 Ottrnan Nov. 14, 1922 1,576,732 Eschholz et al Mar. 16, 1926 face substantially perpen

Images