US2027453A - Centrifugal pipe casting apparatus - Google Patents

Description

Jan- 14,1936 N. F'. s. RUSSELL Erm. 2,027,453

CENTRIFUGAL PIPE CASTING APPARATUS Jan. 14, 1936. N. F. s. RussLl. er A1. 2,027,453

i CENTRIFUGAL PIPE CASTING APPARATUS 5 Sheets-Sheet 2 NN f u ww* a ww. Q m WMHHHF ..2 l QH -...H.............-......H-- -f l gl, M h @NNN Jan. 14, 1936.

N. F. S. RUSSELL ET AL GENTRIFUGAL PIPE CASTING APPARATUS Filed Nov. 3, 1934 5 Sheets-Sheet 3 Mmmm/F5. wssell i Jan. 14, 1936.5

N. S. RUSSELL Er AL CENTRIFUGAL PUE CASTING APPARATUS Filed Nov. 3, 1934 5 Sheets-Sheet 4 Jjwentr Fussell diy Jan. 14, 1936. NI F, s, RUSSELL AL 2,027,453

CENTRIFUGAL PIPE CASTING APPARATUS Filed Nov. s, 1954 `5 sheets-sheet 5 F4 lf3 Z E4 J 5 ks l i h .17H/@Rims /armanl Fuss ell 6r Patented Jan. 14,,1936

UNITED STATES PATENT OFFICE CENTRFUGAL PIPE CASTING APPARATUS Norman F. S. Russell 'and Frederick C. Langenberg, Edgewater Park, N. J.,l assignors to United States Pipe and Foundry Company, Burlington, N. J., a corporation of New Jersey ApplicationY November 3, 1934, Serial No. 751,318

16 Claims. (Cl. 22-65') of centrifugal pipe casting apparatus in which( the metal is delivered by the chute to. a trough having a delivery spout at its end and through said trough and spout to avrelati/vely reciprocable l mold, which mold is rotatable and usually lo.- cated in a water box or equivalent cooling mechanism, supported on a reciprocable carriage and so actuated as to bring about a progressive delivery of molten metal from one end to the other of v20 the mold. As heretofore constructed, the chutes through which the molten metal passes have been constructed with downwardly inclinedchannels having converging side walls sufficiently far apart at the point where the metal from th/e ladle con- .25 tacts with the chute to receive the stream of metal between them and converging in such man- /ner that the breadth of the channel at the de-- livery cnd of the chute corresponds with the breadth of the channelin the trough and it'has 30 been found that at times disgured and defective pipe castings are formed owing to the fact that not infrequently fins or sprays of molten metal are thrown' upward and forward from the surface of the metal stream passing through the chute,

.35' some of which'enter the mold and give rise` to defective castings. Again, it has been found that the metal stream delivered to the trough is at times soY turbulent` as to bring about i a splashing of the 'metalpassing through the 40 trough over its edges which again results in more or less -defective pipes and, again, it has been found that at times the stream of metal issuing from the spout at the end of the Vtrough is so tur-y .l

bulent as to bring about a splashing of a portion 45 of the delivered metal which, again, may result in the production of more or less defective pipes andit 'is the object o! our invention to so construct and combine'the chute with the other parts ofthe casting apparatusl as to' prevent or 50 greatly -lessen the tendency of the metallic' stream passing through the chute to throw out a spray' and at the Sametime to cause the metal to ow throughthe chute and vtrough with a minimum of turbulence and so as to greatly lessen the oc/-j `v55 currence of splashes from the trough and of o and adapted to deliver a stream of molten metal splashingl at the delivery spout of the trough. It/` is a further object of our invention to so modify and reconstruct the structure for supporting the trough in the proper alignment with the mold as to adapt the structure for use with the improved 5 construction of the chute and also to provide an improved structure which will result'in a more perfectalignment of the chute withl the channel formed in the trough than has heretofore been practical. l0

Itis, of course, well known that a falling stream of a liquid, such as molten cast iron, will fall with aconstant acceleration and with .a corresponding decrease in cross-sectional area and. also that a falling stream of liquid such as molten cast iron of more or less irregular shape Will progressively te; .d to a shape having a circular cross-section. Ifthe stream of liquid-instead of falling vertically, flows through a channel inclined to the vertical, its acceleration is modiiied by the trictional resistance encountered and by such energy as is lost in. changes of direction and, as the guiding channel vapproaches the horizontal, ac'- celeration may @ease to occur so that under some conditions the rate of flow of the liquid may be retarded and, again, the forces actingupon a falling stream of liquid to bring it toa circular section are, of course, mitigated where the liquid flows over an inclined surface, Practical consideratidns affecting the construction ofi a centrifugal casting apparatus are such that it is not always practical to locate the ladle with respect to the mold and trough at what might seem from theoretical considerations to be its proper position. The height of the ladle must be such as will bring about a satisfactory rate of flow through the trough and a ksatisfactory outflow of the molten metal through the delivery spout at the end of the trough. Again, the chute channel must be wide enough to 'receive the falling stream of 4o molten iron l`delivered 13A the ladle at its upper end While-at its lower end it 'should have the breadth ofv the channerpmvided in the trough and, as heretofore constructed. the liability of the metal flowing through the chute to throw out sprays of molten metal and to bring about so turbulent a ow as will sometimes cause metal to be thrown over the sides' of the trough and to bring about splashing of the metal as it contacts withthe mold is, we have found, due to the facts, first, thatthe longitudinal contour of the chute chanelhasbeen such as to eiect unduly abrupt changes in the direction of' ow of the molten iron, and, second, that the convergence of the side walls of the chute channel has not been g5 top to receive within its side walls the stream of metal delivered by the ladle and must be narrowed at its delivery end to a breadth substantially the same' as that of the channel in the trough into which the chute delivers the metal stream, we have found itpracticable in all cases to practically eliminate the danger of forming a spray of metal issuing from the surface of the metal stream and to so greatly reduce the turbulence in the stream as to eliminate the spraying of metal from the chute, the occurrence of splashes from the sides of the trough and the occurrence of splashes when the metal contacts with the mold by forming the chute with a bottom longitudinal contour of such character that at or about the point where the metal rst contacts with the chute the inclination of the chute to the vertical would not exceed and which receiving surface is continued as a substantially geometric curve drawn between a tangent of the 30 same angular inclination to the vertical as that of the receiving portion of the chute and a tangent. at or near the delivery end of the chute, forming a slight angle with the horizontal and lying substantially parallel to the trough. By preference the curve should be of such a char- 0 and 20.

acter that 'its tangent at its upper end is considerably less than 30 and it is generally practicable to use a curve the upper tangent of which will form an angle with the vertical of between F By preference the geometric curve is continued to the point of impact of the falling stream of metal but as it is desirable that the curve should ilatten out, so to speak, as it approaches its lower tangent it is desirable that the i5 length of its upper tangent between its point of Y contact with the curve and its point of inter- *lsection with the lower tangent should be shorter than the length of the lower tangent between its point of contact with the upper tangent and its 150l point of contact with the curve.

While any geometric curvature of the chute conforming to the conditions above indicated will give improved results, we have foundthat the most effective and satisfactory curve is that of a parabola which, especially where the curvature progressively diminishes as the delivery end of the chute is approached, will, we have found, bring about a ilow of the molten metal with minirum turbulence and minimum tendency Lto throw out a spray of metal from the surface.

With regard to the contour of the side walls of the chute channel, these walls must be spaced apart at the line of impact of the metal falling frqm the chute by a distance equal to the breadth of the stream of metal while at the delivery end of the .chute and preferably somewhat in advance of the delivery end, the breadth of the channel between the side walls must be essentially the sameas the `breadth of the channelin the trough into which tliemetal is delivered. The

vertical height of the chute must be auch as, in view of the general inclination and shape of the channel formed in the chute, will result in impartingto the stream of molten metal at the delivery end of the chute a velocity'which will carry the stream of metal into and through the trough at a rate of speed which will keep the level of the stream in the trough suiliciently below the top edges of the channel to avoid the risk of the metal spilling over the sides of the trough and, at the same time, to secure the delivery of the metal to the spout at the end of the trough at such moderate velocity and absence of turbulence as will not bring about splashing of the metal as it comes in contact with the mold. It will be understood, of course, that the ladle delivering the molten metal to the chute and its actuating mechanism should be of such a character that it is adapted to deliver its contents at an even rate, is necessarily so located and constructed that its pouring lip will, under all conditions, lie at a somewhat higher level than that portion of the chute to which it delivers a stream of metal so that the metal stream as it ilrst contacts with the chute is already moving with a velocity determined by the rate of pouring and the height of its fall from the lip of the ladle; this involves that the breadth of the chute at the point of contact should be somewhat less than the length of the lip and, consequently, that the forces we have mentioned 4tending to diminish the cross-sectional area of the stream and change its form will have resulted, at the time the stream contacts with the chute, in somewhat narrowing the breadth of the stream but the distance through which the metal falls freely from the ladle is yin practice made as short as practicable and the chute itself is relied upon to effect in great part the necessary narrowing of the breadth of the stream to a breadth corresponding to the breadth of the channel in the trough and the problem which confronted us with regard to the contour of the side walls of the trough channel was to give themvsuch a shape as would effect the necessary narrowing of the stream of metal under conditions which would not bring about a spraying of the metal or undue turbulence in the flowing stream. In considering this problem we had to take into account that in casting pipes of diierent sizes, it is necessary to use chutes of varying vertical height with, of course, corresponding changes in the vertical height of the ladle above the level of th trough and that practical considerations do not always make it possible to use chutes of a horizontal length which stream would narrow in falling freely through a a vertical distance equal to the length of the chute between the point where the metal contacts with it and the point where it is delivered would aii'ect the narrowing of the stream with but little tendency to produce turbulence but, as we have explained, the breadth of the stream at the delivery end of the chute must be practically the vsame as that of the channel into .which the metal is delivered and the breadth of the stream delivered by the ladle to the upper part of the chute cannot be arbitrarily limited though in many cases it is n practicable to so construct the ladle and its pournig 11p that it' will denver to Athe chute a stream of metal the breadth of which at the point of impact will not exceed eight times the breadth of the stream at the delivery end of the chute and we have found it highly advantageous that this ratio sliould not be exceeded and, where practicable, should be less. In most cases it is not practicable to give the chute a horizontal length such v'as would betheoretically desirable but we have discovered that inall cases a reasonably satisfactory nonturbulent ow of the molten metal through and from the chute can be secured by giving to the side walls o'f the channel in the chute lthe form of converging geometric curves upon.

which the trace of the center line ofv the chute channel, when developed to its true length on a horizontal plane, will have a curvature at the upper end of the curve corresponding approximately to the point of impact of the metal and will have a tangent forming an angle with the center line of the chute not to exceed 30 and which, at the delivery end of the chute, will have a tangent substantially parallel to the center line of the chute. By preference, and when compatible with the angularity of the upper tangent to the center line of the'chute, the tangent lines their point of intersection with each other/'should be approximately of the same length and while improved results are obtainable with practically all curves drawn in accordance with the provisions above given, we have vfound that the most effective curvature for the side walls is that of a parabola and, in speaking of the curvature of the side walls, it should be understood that we are speaking of the curvature of the trace of the center line of the chute upon the surface of the side walls as such trace is developed4 on a horizontal plane as this is the curvature of the side wall which is actually followed by the ilowing metal y and this is the improved construction as effecting 'form of the-surface of the chute, and, for the best resuus, both the bottom and side` walls of the chute channel should be given the forms which we have indicated and, again, we would point out that while in most case's it is advantageous that vthe curves of the center line of the chute and of its side walls should continue to approximate the delivery end of the chute, our invention can be advantageously used with chutes in which the bottom curvatureof the chute channel merges into a straight line and in which the,side walls, to a corresponding distance, may run ,parallel to each other before merging into curves which we have described. l With regard to the form of the chute above the line of impact of the metal falling upon it, this, it will be understood, isimmaterial so far as our invention is concerned and will be, determined by practical considerations involving the necessary clearance of the ladle lip. y f

It will, of course, be understood that in describing the curvature ofthe centerline and side walls of the chute as geometrical curves we are not to bve understood as limiting ourselves to truly mathematic curves as such perfection of curvature is hardly practical of attainment but curves ap-Y proximating the curvatures which we have de-l scribed are entirely practicable and can follow within the scope of our invention.

As ,examples of .chutes -which we have designed and successfully used in practice, we will give the following:

Example one Height of chute, 161/2 inches; horizontal length of chute, 43 inches; distance between side walls at line of impact of metal, 1&inches; breadth of channel at delivery end of chute, '3 inches; center vline of channel, a parabolic curve drawn be- .tween a tangent at its upper end forming an angle of 15 with the vertical and a tangent at its lower end forming an angle of 31/ with the horizontah, curvature of side walls along the trace of the center line upon lsaid walls as developed in a horizontal plane; parabolic curves drawn between the tangent at the upper end of the chute forming an angle of 18 with the center line of the chute and a tangent at the delivery end of the 'chute lying parallel to the center line.

Errample two Height of chute, 231A inches; horizontal length of chute, 361/4 inches; distance between side walls at line of impact of metal, 12 inches; breadth of channel atdelivery end of chute, 21/2 inches; center line of channel, a parabolic curve drawn be'' tween a tangent at its upper end forming an angle of 30 with the vertical and a tangent at its lower end forming an angle of 3 with the horizontal; curvature of side walls along the trace of the center line upon said walls as developed in a horizontal plane; parabolic curves drawn between the tangent at the upper end of the chute forming an angle of 13 with the center line of the chute and a tangent at the delivery end of the chute lying parallel to the center line.

Example three Height of chutei 181/2 inches; horizontal length of chute, 531/2 inches; distance between side walls at liney of impact of metal, 18 inches; breadth of channel at delivery end of chute, 3 inches; center line of channel, a parabolic curve drawn between a tangent at itsiupper end forming an' angle of 20 with the vertical and a tangent at its lower end forming an angle of 2 with the horizontal; curvature of side walls along the. trace of the center line upon side walls as developed in a horizontal plane; parabolic curves drawn between the tangent at the upper end of the chute forming'an angle of 15 with the centerline of the chute and a tangent at the delivery end of the'chute lying parallel to the being provided for nearer the point where the trough enters the mold in the more advanced position of the mold and the chute has been supported in and by the trough at its lower end and by adjusting screws located at the top of the ladle supporting structure and the chute has been kept in abutting contact with the lining blocks with which the trough is provided by a .spring located in the rear portion ofthe trough and abutting against the shoulder formed on the chute and lying in the trough. It is impracticable in these older constructions to form a chute with the channels substantially conforming to our improved construction nor do the means heretofore employed for supporting lthe chute reliably secure an accurate abutment of the delivery end of the trough against the 1ining blocks and to provide a structure suitable for use in connection with our improved chutes and a more reliable way of securing and maintaining a proper alignment of the chute with the lining blocks of the trough we construct the trough so that it'will not extend forward beneath the chute to a greater extent than is necessary to afford a seat for the delivery end of the chute and secure to the front end of the trough a forwardly extending supporting structure preferably formed by beams firmly secured to the sides of the trough the side walls of which structure are so spaced apart as to alfford clearance for the portions of the chute structure which may extend between them and which are, moreover, so spaced apart as to afford a good supporting base upon which lugs or feet extending down from the upper and wider portions of the chute may rest so that the chute is supported entirely upon the front end of the trough and upon the sidewalls of the troughv supporting structure. Our new construction fur.

ther involves the provision of a guideway supported by the trough supporting structure upon which are slidingly supported and guided spring caps, one abutting against a. shoulder formed on thechute and the other against a suitable support and holding between them a spring adjusted to maintain the delivery end of the chute in contact with the lining blocks Vof `the trough and,

to protect the spring and spring supporting structure from being fouled by molten metal or Vfoundry dirt, we secure to the side walls of the trough supporting structure a cover plateextending over the spring structure and our improvements will perhaps be better understood as further described in connection with the drawings in which Figure 1 is an elevation of a centrifugal pipe casting machine embodying our improvements taken on a central longitudinal section.

Figure 2 is a fragmentary plan views., of the chute, the end of the trough on which it is supported and ia portion of the trough supporting structure, shown on a larger scale than Fig. 1.

Figure 3 is a sectional elevation of apart of the structure shownin Fig. 1, on a large` scale.

Figure 4 is across-sectional view on the line 4 4 of Fig. 3.'

Figure 5 is an elevation viewed from'the left of the chute and trough supporting structure.

Figure 6 is a cross-sectional View on the line l-6 of Fig. 3.".

of laying out the curves of the side walls of the chute in what we believe to be their' most effective curvature, and

Figure 18 is'a diagram illustrating an effective way of laying out the curve of the center line of the chute in what we believe to be its most eiiective curvature.

A indicates the framing forming the base of the pipe casting machine, A1 an elevated structure or tower supporting the ladle indicated at A2, a2 indicating the lip oi' the ladle. Mechanism for tipping the ladle is indicated at As and, as it forms .no part of our invention, need not be described in detail. A* indicates the carriage supported on wheels a4 and supporting a water box A5 traversed by a rotatable mold A to which rotary motion is by a mowr A" and gears A. Reciprocating motion is given to the carriage by a cylinder and piston as indicated at A9. In all of the above noted featureshthe apparatus is of usual construction. B indicates the trough structure made up, as shown, of an outer casing B1 which is divided into a central or trough structure and water circulating chambers B5, B3, by partitions indicated at B4, B4. B5, B5, indicate water supply -pipes for introducing water into the water circulating chambers, B5, B5, indicating lining blocks in the trough section through which is formed 'the y trough channel and B" indicates the terminal or delivery spout of the trough. In all ofy the above noted features the trough structure is oi well known construction but as heretofore constructed the described trough structure, with the exception oi' the lining blocks, is continued'iorwardly, that is to say,U toward the structure supporting the ladle to a support, whereas in our present construction the trough is continued forwardly only to a sufllcient distance to afford a seat and support for the end of the chute -to be described.v

In our new construction, supporting means for the trough are attached to its forward end and formed with side walls spaced apart by a sufilcient distance, greater'than that of the trough proper, to aiiord clearance to the portions of the chute which extend between the walls and a rm support for the front or upper portion of the justing screws, indicated at D1, are provided for the proper alignment of the trough.

Returning to the structure for the support of the front end of the trough, C4, C4, are plates se- I.

cured to the lower sides of the beams C, C, and supporting in turn a central longitudinal guideway C5, indicated as a channel beam. Supported onwand guided by this channel beam are spring caps C5, C5, one abutting against a shoulder on the chute as will be described and the other abutting against an adjusting screw indicated at C". C indicates a spring, the ends oi' winch are engaged in the spring caps, and C is ia cover plate extending between the beams C. C. f and4 serving as a protection to the spring structure described. (n v x* E indicates our new chute construction, the chute being .provided to receive the metal as it is poured out from the ladle and deliver-it to the front end of the trough. Chutes for this -purpo'sefhave heretofore been in use and have kbeen prvided with side walls spaced apart at their upper ends by a distance greater than the .y Y. of sulcient volume to supply the mold and bring about the production of a pipe o! the desired the development of a chute which will impart the necessary velocity to the stream of metal passing through it and the necessary change in cross sectional form with a minimum degree of turbulence in the flowing stream of metal and with .this object in view we form the bottom of the chute channel so that approximately at the point indicated at E1 where the falling stream of metal first contacts with the chute it will form an angle of not more than 30 with the vertical, a smaller angle being preferable and we continue the bottom of the-chute channel, thecenter line of which is indicated at E2, as a geometric curve merging into the receiving surface at the top of the chute and having at its upper end a tangent lying in the receiving face of the channel and having, of course, the same angular inclination with the vertical and another tangent at the delivery end 'of the chute which is approximately horizontal and preferably forming' only such angle with the horizontal as is the case with the channel in the trough to which the chute delivers its metal. The curved surface of the chute channel, as is indicated at E3, and which preferably extends from the point of impactof the metal, indicated at E1, has a continuous curve to the delivery end of the chute and, for the best results, this curve should be a parabolic curve, or curved segment, although other geometric curves filling the same condition as to tangency may be used with advantage as compared'with previously ex' isting contours .of the chute surface. The essential conditions to have in view are, that the metal falling fromthe ladle should not strike a chute surface of a greater angularity to the vertical' tangent to which at the delivery end of the chute f should lie practically parallel to the channel in the trough. It is, however, decidedly advantageous that the curvature o-f the chute channel as it approaches the delivery end of the chute should be of progressively decreasing curvature and this, where other conditions make it practicable, should be provided for byr'so constructing the chute that the tangent line from the upper end of the curve to its point of intersection with the tangent line from the lower end of the curve should be shorter than the length of the tangent line from thelower end of the curve to the point of intersection. In Fig. 18, we have illustrated the laying out of the center line of the chute in a parabolic curve. Thebroken line F indicates the vertical 'height of the chute and the partly broken and partly fulll line F1 and FG, of which the full line portion F3 is a tangent line, ,indicatevthe horizontal length of the chute. The tangent to the upper end of the curve is indicated at yF3 and the tangent to .the lower end of the curve is indicated at F3, their point of intersection, being indicated at F4. In laying off the parabolic curve between these two tangents, a convenient and satisfactory plan is to divide the two tangent lines F2 and F3 into the same number of divisions as indicated on the .upper tangent line at f1,

`g1, g2, g3, g4, g5, g6 and g", then drawing straight lines, as indicated, from f1 to g1, from -P to g. etc. These lines willV form tangents of a parabolic curve and facilitate the laying out of such a curve for the use of the pattern makers.

The side walls of the chute channel which areI indicated at E4, E4, are necessarilyspaced apart at their upper ends byl a distance slightly greater than the breadth of the stream of metal falling upon the chute from the ladle and necessarily converge so that at the delivery end of the chute they are distant from each other by approximately the same distance as the' width of the trough channel. The function of the side walls is to contract the stream of molten metal which is, for the greater part of its passage through the chute, moving with accelerating velocity and consequently with progressive contraction of its cross-sectional area. 'I'he forces bf molecular attraction and surface tension which tend to bring a'falling stream of liquidof irregular shape to a form having a circular cross-section are also, to some extent, operative even when the liquid is owing over an inclined surface although opposed in such a case by the weight of the metal tending to spread it out over its supporting surface. Our investigations have led us tod believe that a side wall construction in which the walls would converge toward each other approximately as the sides of the falling stream would converge in ifalling through a distance approximating the vertical distance between point of irst contact and point of delivery, would bring abouta narrowing of the stream with the least possible turbulence but in practice the height and length of the chute channel are determined by other considerations and in developing a construction of the side walls of the chute which will in prac- 'tice produce a minimum turbulence in the flow of the molten iron we have had to take all practical considerations into account, inclusive of such changes in the height and length of chutes as are found necessary in the casting of pipes of different diameters and varying wall thickness as well as the adapting of our improved chutes for substitution in pipe casting machinery already existent. The essential curvature of the side walls is of that portion of the walls with which the metal 'actually contacts in the passage through the chute channel, that is to say, of portions of the side walls lying approximately opposite to the center line of the chute and following the curvature of said centerline, said portions of the side walls having, so to speak, a double curvature, that is to say, curving downward from the upper portion of the chute to its delivery end and inward toward the center line of the chute and we have found that an effective and satisfactory curvature of the side walls should be such that the trace of their surfaces upon the bottom surface 'of the chute when developed to its true length upon a horizontal plane, will form a geometric curve, preferably a parabolic curve lying between tangents, the upper Aone of which will .form an angle of not to exceed 30 with the developed center line of the chute and the lower.

one of which, at the delivery end of the chute, will be essentially parallel with the center line.

.Where practicable the length of the tangent ture of the side walls of the chute with parabolic curves along the line of fiow ofthe metal whereit contacts with the side walls. In this diagram, E, E3, represent the development of the centerline of the chute to its true length as a straight line between the point of first contact and point of delivery. At the upper end of this line we erect a right angle line indicated at H and of a length equal to half the breadth of the chute channel at or about the point of contact of the molten metal and at the lower end of the developed center line corresponding to the delivery end of the chute we erect a right angle line H1 of a length equal to half the breadth of the chute channel at this point. From the end of the line H, which corresponds approximately to thepoint on the sidawall where the metal stream from the ladle iirstcontacts with it, we draw a line H2 forming an angle of not more than 30 with the center line E, E3, and from the end of the line H1 we draw a line H3 parallel to the center line and we then lay out a geometric curve H* of such a character that the lines H2. and H3 will form tangents to the curve at the points on the lines H and Hl from which such tangent lines are drawn ani-subject to the stated limitation as to the angle which the tangent line H2 must form with the center line of the chute, we draw the lines H2 and H3 at such angularity with each other that they will intersect, as indicated at H5, at av point equi-distant from the two points of tangency to which the tangents are drawn. The curvature of the developed trace of the center line upon the side walls is preferably that of a parabolic curve which is conveniently drawn, as indicated in Fig. 17, by dividing the tangent H2 into any desired number of equal parts, as indicated at h1, h2, h3, h4, 115,111.6 and h", and dividing the tangent line H3 into the same number of equalparts as indicated at i1, i3, 3, #,15, i and i", and then drawing a series of straight lines connecting the division points h1 and i1, h3 and i3, etc., which lines will form tangents to a parabolic curve and practically facilitate the laying out of such a curve for theuse o1' the pattern maker.

In referring to other geometric curves as possible substitutes for parabolic curves in the center line of the chute and in the contour of the side walls as developed we have in mind such curves as can be laid out between intersecting tangents and while it is true that such curves, other than parabolic curves, will give improved results as compared with the contour'lines of chutes as previously used in centrifugal pipe casting machines, we have found that the parabolic curves are decidedly better than others as bringing about the ow of molten metal through the chute with the minimum of turbulence.

The delivery end of the chute indicated at E5 is formed, as we have stated, with its channel conformed in cross-section to the shape of the channel formed through the lining blocks B of the trough and with its outer dimensions conformed to-the shape of the` front end of the trough .B in which this delivery end 0! 4the chute is supported( with its extreme end abutting against the front lining block of the trough and it is important that the fitting of the end of the chute against the front lining block should be reasonably accurate and not afrectedby ad' justments o'f the trough and to secure an accurate and permanent alignment of the chute with the trough we provide the front or upper end of the chute with downwardly extending supporting legs as indicated at E, E', which enses@ IJld rest upon the tops of the side walls of the supporting structure C, thereby insuring in all adjustments of the trough and its supporting structure that the proper alignment of the chute and trough shall be maintained.

On the underside of the chute we provide a spring abutment shoulder indicated at E", against which the rear spring cap C6 abuts and the necessary compression is given to the spring C3 by shifting the front spring cap C6 by the adjusting screw C7.

The assembly and operation of our improved machine will be clear to those skilled in the art from the above description and need not, we believe, be further detailed.

Having now described our invention, what we claim as new and desire to secure by Letters Patent, is:

1. In centrifugal pipe casting apparatus comprising a rotatable mold, a conduit for the delivery of molten metal extending into the mold, a ladle adapted to contain and deliver molten metal located in front of and at a higher level than the mold, the combination therewith of an inclined chute adapted to receive the metal from the ladle and deliver it to the conduit entering the Infeld, which chute is formed with a bottom contour which, at approximately the point where the metal from the ladle first contacts with the chute,is inclined to the vertical at an angle not exceeding 30 and which is continued as a geometric curve of progressively decreasing curvature having at its upper end a tangent coincid-l ing in angular inclination with the angular inclination of the chute at the point of impact of the metal and having at the lower end of the curve an approximately horizontal tangent.

2. In centrifugal pipe casting apparatus comprising a rotatable mold, a conduit for the delivery of molten metal extending into the mold, a ladle adapted to contain and deliverv molten metal located in front of any at a higher level than the mold, the combination therewith of an inclined chute adapted to receive the metal from the ladle and deliver it to the conduit entering the mold, which chute is formed with a bottom contour which, at approximately the point where the metal from the ladle first contacts with the chute, is inclined to the vertical at an angle not exceeding 30 and which is continued as a substantially parabolic curve drawn between a tangent of the same angular inclination to the vertical as that of the receiving portion of the chute and an approximately horizontal tangent, at or near the delivery end of the chute.

3. Apparatus'as called for in claim 2, in which the parabolic curvature ofc the bottom contour of the chute is of such a character that the length of the tangent drawn from the upper end of the parabolic curve to a point of intersection with the tangent line drawn from thev lower end of the parabolic curve will be less than that of the tangent line drawn from 'the lower point oi.' the curve to the point of intersection.

4.' Apparatus as called for in claim 2, in which the parabolic bottom curvature of the chute is continued at its upper end to approximately the point where the metal from the ladle iirst contacts with the chute.

5. In centrifugal pipe casting apparatus comprising a rotatable mold. a conduit for the delivery of molten-'metal extending into the mold, a ladle ladapted to contain and deliver molten metal located in front of and at a higher level than the niold, the combination therewith ot an inclined chute adapted to receive the metal from the ladle anddeliver it to the conduit entering the mold, which chute is formed with a bottom contour which, at approximately the point where the metal from the ladle rst contacts with the chute, is inclined to the-vertical at an angle not exceedingv30 and which is continued as a geometric curve having atits upper end a 'tangent coinciding in angular inclination with the anguiar inclination of the chute at the point of impact of the metal and having at the lower end of the curve an approximately horizontal tangent, further characterized in that the chute is vprovided with side walls which, at the point where the metal frointhe ladle contacts with the chute, are spaced apart by approximately the breadth of the metal stream falling'from the lip of the ladle and at the 'delivery end of the chuteby the breadth of the stream of metal which the chute is designed to deliver and which side walls progressively converge in `relatively convex curves of such a character that the trace. of the bottom line of the chute thereupon will, when developed to its true length upon a horizontal plane, form a geometric curve drawn between a tangent to the upper end of the curve forming an angle of not more than 30 with the centerline of the chute and a tangent to the lower end of the curve lying parallel to said center line.

6. ,In centrifugal pipe casting apparatus comprising a rotatable mold, a conduit for the delivery of molten metal extending into the mold, a ladle adapted to contain and ldeliver molten metal located infront of and at a higher level than the mold, the combination therewith of a chute adapted to receive the metal from the y ladle and deliver it to the conduit entering the mold, which chute is formed with a downwardly inclined channel for the passage of molten metal having side walls which, at the point where the metal from the ladle contacts with the chute, are spaced apart by a distance not materially greater than the breadth of the stream yof molten metal delivered from the lip of the ladle at the time it contacts with the chute and which,

at or near the delivery end of the chute, are spaced apart by a `distance substantially the same as the breadth of the conduit into which -the chute delivers the molten metal, each of said converging side walls having a surface contour which passes through a point at or adjacent to that at which the metal of the ladle first contacts with the side wall andl throughv a point at the lower end of the chute/which is distant from the center line of the chute by half its width. said surface contour'being such that the trace formed by it upon the surface contour of the i bottom of the chute, when developed to its true length, will be a curve, a tangent' to which at the point where the metal rst contacts with the wall of the chute will form an angle with the center line of the chute of not more than 30 and at the point at the lower end of the wall will have a tangent essentially parallel to the center line.

, .'I. In fentrifugal pipe casting apparatus comprising a rotatable mold, a conduit for the delivery of molten metal extending into the mold, aladle adapted to contain and deliver molten metal located in front of and at 'a higher level than the mold, the combination therewith of. a chute adapted to receive the metal from .the ladle and deliver it to theconduit entering the mold, which chute is ormedwith a downwardly inclined channel for the passage cf molten metal having side walls which, at the point where the metal from the ladle contacts with the chute, are spaced apart by a distance not materially greater than the breadth of the stream of molten metal delivered from the-lip of the ladle at the time it contacts with the chute and which, at or near the delivery end of the chute, are spaced apart by a distance substantially the same as the breadth of the conduit into which the chute delivers the molten metal, each of said converging side walls having a surface contour which passes through a point at or adjacent to that at which the metal of the ladle irst contacts with the side wall and throughapoint at the lower end of the chute which is distant from the center line of the chute by half its width, said surface contour being such that the trace formed by it upon the surface contour of the bottom of the chute, when developed to its true length, will be a curve, a tangent to which at the point where the metal rst contacts with the wall of the chute will form an angle with the center line of the chute of` not more than and at the point at the lower end of the wall will have a tangent essentially parallel to the center line, said side wall curvature being `further characterized in that the tangents from the upperl and lower ends of the curved wall intersect each other at a point approximately equi-distant from the two points of tangency.

8. In centrifugal pipecasting apparatuscomprising a rotatable mold, a conduit for the delivery of molten metal extending into the mold, a ladle adapted to contain and deliver molten metal located in front of and at a higher level than the mold, the combination therewith of a chute adapted to receive the metal from the ladle and i nel for the passage of molten metal having side walls which, at the point where the metal from the ladle contacts with lthe chute, are spaced apartbyadistance not materially greater than the breadth of the stream of molten metal delivered from the lip of the ladle at the time it contacts with the chute and which, at or near the delivery end of the chute, are spaced apart by a distance substantially the same as the breadth of the conduit into which the chute delivers the molten metal, each of said converging side walls having a surface contour which passes through a point at or adjacent to that at which the metal of the ladle rst contacts with the side wall and through a point at the lower end of the chute which is distant from the center line of the chute by half its width, said surface contour being such that the trace'formed by it upon the surface contour of the bottom of the chute, when developed to its true length on a horizontal plane, will be a subf stantially parabolic curve, a tangent to which at the point where the metal rst contacts with the. wall of the chute will form an angle with the center line ofthe chute ofnot morethan 30 and at the point aty the lower end of the Wall will have a'tangent essentially parallel to the center line. D

9. In centrifugal pipe casting apparatus comprising a rotatable mold, a conduit for thedelivery of molten metal extending into the mold,

a ladle' adapted to contain and deliver molten inclined channel for the passage of molten metal having side walls which, at the point where the metal from the ladle contacts with the chute, are spaced apart by a distance not materially greater than the breadth of the stream of molten metal delivered from the lip of the ladle at the time it contactsgwith the chute and which, at or near the delivery end of the chute, are spaced apart by a distance substantially the same as the breadth of the conduit into which the chute delivers the molten metal, each of said converging side walls having a surface contour which passes through a point at or adjacent to that at which the metal of the ladle first contacts with the side wall and through a point at the lower end of the chute which is distant from the cen ter line of the chute by half its width, said surface contour being such that the trace formed by it upon the `surface contour of the bottom of the chute,when developed to its true length on a horizontal plane will be a substantially parabolic curve, a tangent to which at the point where the metal first contacts with the wall of the chute will form an angle with the center line of the chute of not ore than 30 and at the point at the lower end o the wall will have a tangent essentially parallel to the center line, said side wall curvature being further characterized in that the tangents from the upper and lower ends of the curved wall will intersect ealch other at a point approximately equi-distant from the two points of tangency.

10. In centrifugal pipe casting apparatus comprising a rotatable mold, a conduit for the delivery of molten metal extending into the mold, a ladle adapted to contain and deliver molten metal located in front of and at a higher level than the mold, the combination therewith of a chute adapted to receive the metal from the ladle and deliver it to the conduit entering the mold, which chute is formed with a bottom contour which, at aproximately the point where the metal from the ladle flrst'contacts with the chute, is inclined to the vertical at an angle not exceeding 30 and which is continued as a substantially parabolicI curve drawn between a tangent of the same angular inclination to the vertical as that of the receiving portion of the chute and a tangent, at or near the delivery end of the chute, forming a slight angle with the horizontal, said chute being further characterized in that the channel formed therein for the passage of molten metal is formed with side walls which, at the point where the metal from the ladle contacts with the chute, are spaced apart by a distance not materially greater than the width of the stream of molten metal at the time it contacts with the chute and which, at or near the delivery end of the chute. are spaced apart by a distance sub- 'stantially the same as the breadth of the conduit into which the chute delivers the molten metal, each of said converging side walls having a surface contour which passes through a point at or adjacent to that at which the metal of the ladle first contacts with the side wall and through a point at the lower end of the chute which is distant from the center line of the chute by half its width. said surface contour being such that the trace formed by it upon the surface contour of the bottom of the chute, when developed to its true length. will be a parabolic curve, a tangent to which at the point where the metal first' contacts with the wall of the chute will form an angle with the center line of the chute of not more than 30 and at the point at the lower end of the wall will have a tangent essentially parallel tothe center line, said tangents in the development subject to the angular limitation intersecting each otherat a point approximately equi-distant from the two points on the curve to which' the tangents are drawn.

l1. In centrifugal pipe casting apparatus comprising a trough or runner having a delivery spout at its end, a relatively reciprocable centrifugal mold, a ladle for containing and delivering molten metal located above and in front of the mold and trough, the combination therewith of a chute adapted to receive the metal from the ladle and deliver it to the trough and through the trough to the mold, having a channel which at its delivery end conforms to the shape of the channel in the trough, which chute is formed with a bottom contour which, at approximately the! point where the metal from the ladle first contacts with the chute, is Ainclined to the verticafat an angle not exceeding 30 and which is continued as a substantially parabolic curve drawn between a tangent of the same angular inclination to the vertical as that of the receiving portion oi' the chute and a tangent at the lower end of the chute ,substantiallytparallel to the trough.

12. In centrifugal pipe casting apparatus comprising a trough or runner having a delivery spout at its end, a relatively reciprocable centrifugal mold, a ladle for 'containing and delivering molten metal located above and in front of the mold and trough; the combination therewith of a chute adapted to receive the metal from .the ladle and deliver it to the trough and through the trough to the'mold, which chute is formed with a downwardly inclined channel for the passage of molten metal having side walls which, at the point where the metal from the ladle contacts with the chute, are spaced apart by a distance not materially greater than the Width of the stream of molten metal at the time it contacts with the chute and which, at the delivery end of the chute, are spaced apart by a distance substantially the same as the breadth of the channel in the trough into which the chute delivers the molten metal, each of said converging side walls having a surface contour vwhich passes through a point at or adjacent to that atV which the metal of the ladle first contacts with the side wall and through a point at the lower end of the chute which is distant from the center line of the chute by half its width, said surface contour being such that the trace formed by it upon the surface contour of the bottom of the chute, when developed to its true length, will be a parabolic curve, a tangent to which vat thev point where the metal first contacts with the wall of the chute will form an angle with the center line of the chute of not more than 30 and at the point at the lower end of thel wall will have a tangent essentially parallel to the center line, said tangente in the development subject to the angular limitation intersecting 'each other at a point approximately equi-distant from the two points on the curve to which the tangents are drawn. A

13. In centrifugal pipe casting apparatus comprising a trough or runner having a delivery spout at its end, a relatively reciprocable centrifusal mold, s. ladle for containing and delivering molten metal located above and in front of the mold and trough, the combination therewith of a chute adapted to receive the metal from the ladle and deliver it to the trough and through the trough to the mold, which chute is formed with a bottom contour which, at approximately the point where the metal from the ladle iirst contacts with the chute, is inclined' to the vertical at an angle not exceeding 30 and which is continued as a substantially parabolic curve drawn between a tangent of the same angular inclination to the vertical as that of the receiving portion of the chute and a tangent, at or near the delivery end of the chute, forming a slight angle with the horizontal, said chute being further characterized in that the channel formed therein for the passage of molten metal is formed with side walls which, at the point where the metal from the ladle contacts with the chute, are spaced apart by a distance not materially greater than the width of the stream of molten metalat the time it contacts with the chute and which, at the delivery end of the chute, are spaced apart by a distance substantially the same as the breadth of the channel in the trough into which the chute delivers the molten metal. each of said `converging side walls having a surface contour which passes through a point at or adiacent to that at which the metal of the ladle iirst contacts with the side wall and through a point at the lower end of the chute which is distant from the center line of the chute by half its width, said surface contour being such that the trace formed by it upon the surface contour of the bottom of the chute, when developed to its true length, will be a parabolic curve, a tangent to which at lthe point where the metal first contacts with the wall of the chute will form an angle with the center line of the chute of not more than 30 and at the point at the lower end of the wall will have a tangent essentially parallel to the center line, said tangente in the development subject to the angular limitation intersecting each other at a point approximately equi-distant from the two points on the curve to which the tangents are drawn.

14. In centrifugal pipe casting apparatus comprising a trough or runner having .a delivery spout at its end, a relatively reclprocable centrifugal mold, a ladle for containing and delivering molten metal located above and in front of the mold and trough, the combination therewith of a vchutey adapted to receive the metal from the ladle and deliver it to the trough and through the trough to the mold, having a channel which, at its delivery end, conforms to the shape of the channel in the trough, which chute is formed with a bottom contour which, atapproximately the point wherethe metal from the ladle rst contacts with the chute, is inclined to the vertical at an angle not exceeding 30 and which is continued as' a substantially geometric curve drawn between a tangent of the same angular inclination to the vertical as that'of the receiving portion of the chute and a tangent at the lower end of the chute substantially parallel to the trough, and further characterized in that the delivery end of the chute entersvand is supported by the front end of the trough and the trough is provided with a forwardly extending angularly adjustable supporting structure having side walls which at their upper portions are spaced apart by a greater distance than that of the side walls of the trough structure and so as to give clearance to such portions of the chute as may extend between them. I

l5. In centrifugal pipe casting apparatus comprising a trough or runner having a delivery spout at its end, a relatively reciprocable centrifugal mold, a ladle for containing and delivering molten metal located above and in front of the mold and trough and an inclined chute ar-L l ranged to receive the metal from the ladle and deliver it to the trough, the improved construction in which the delivery end of the chute enters and is supported by the front end of the trough and the trough is provided with a forwardly extending angularly adjustable supporting structure having side walls which at their upper portions are spaced apart by a greater distance than that of theside walls of the trough structure and so as to give clearance to such portions of the chute as may extend between them and in which the chute is supported at its delivery end by the trough and at its receiving end by the side walls of the supporting structure.

16. In a centrifugal pipe casting apparatus comprising a rotable mold relatively retractable which enters the trough and abuts against the 40 lining blocks of the trough and the upper end of which is located to receive molten metal from the ladle. the improvement which consists ln so constructing the trough that its front end does not extend substantially farther beneath the chute than that portion of the lower end of the chute which lies in the front end of the trough, combining with the front end of the trough a forwardly extending angularly adjustable supporting structure having side walls spaced apart by a greater distance than that separating the side walls and that portion of the trough structure in which the end of the chute is supported so as to afford increased clearance for such'portions of the chute as may extend 55 beyond the frontend of the trough proper, means for supporting and angularly adjusting the supporting structure and means supporting the upper end of the chute supported by and angularly adjustable with the trough supporting |30 structure.

' NORMAN F. S. RUSSELL.

t FREDERICK C. LANGENBERG.

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