US1374750A - Method of pouring metal in the formation of cast-iron pipes - Google Patents

Description

J. R. McWANE. METHOD OF POURING METAL IN THE FORMATION OF GAST IRON PIPES.

APPLICATION FILED MAR. 23. 1920.

INVENTOR,

Patented Apl 12, 1921.

WlTN ESS E$ ATTO R N EY turns a. ucwma or simmem, mm

mansion or rouame 1,374,750.

To all whom it may concern Be it known that I, JAMES R. MoWANn,

a citizen of the United States, residing at Birmingham, in the county of Jefferson and State of Alabama, have invented new and useful Methods of Pouring Metal in the Formation of Cast-Iron Pipes, of which the following is a specification.

This invention has reference to a method of pouring metal, especially for the production of cast iron plpe and the like.

The invention has more particularly to do with the centrifugal rocess of casting which heretofore has, rom a commercial standpoint, been limited to the casting of short lengths of pipe of much less extent than those called for by standard English and American practice, which pipes range from twelve feet to sixteen feet in length.

The centrifugal casting of pipe is employed in order to do away with the necessity of a central core which is needed in casting pipe in upright mold. 'In the centrifugal casting the mold is revolved about a horizontal axis, and the molten metal A poured into' the mold is caused, by centrifugal force, to flow out against the inner wall of themold while the latter is revolved. In this. way, centrifugal force is made to enter into the procedure, and by properly regulating the factors entering into the'process, the molten metal clings to the walls of the mold and is there held until it solidifies. 4

In pouring the metal into one end of the horizontal mold, the hot metal flows toward the other end of the mold, carrying with it loose sand or other foreign matter that may be in the mold or in the iron and washing it to the end of the mold remote from the pouring point, thereby concentrating such lmpurities in one location. 'Moreover, when the molten iron runs from one end to the other of the mold, it becomes progressively dull or sluggish; that is, the temperature of the iron lowers. and the iron thickens because of the lowering temperature so that it glows with less intensity and slows up in speed. It is very essential that the flowing iron not only be as hot as possible at each point along the mold when the mold begins to revolve, but the distribution of the temperature should be even, for unless the temperature along the entire length of the pipe Specification of Letters Patent.

is man FORMATION or CAST-IRON runs Patented Aipr.12, 1921.

Application filed March 28, 1920. Serial No. 868,173.

be high and sensibly even, the casting is not sa-tlsfactory.

Another difiiculty which has been experienced in such casting is due to the surging I that results when the iron is cured rapidly into the mold. It runs quic y to the farther end of the mold and then surges back and forth until it finally settles. In order to secure uniformity of thickness from end to end, the pouring must be performed in such a way as to reduce the surg- 1 to a minimum or entirel eliminate it. n accordance 'with the invention, the

pouring is so performed as to introduce the niolten iron at both ends of the mold, but n'otsimultaneously. Ladles of suitable capacity are provided at opposite ends of the mold and metalfrom one ladle, say at the bell end of the mold, is poured into the mold to an extent of about one half of the iron in the ladle, this being done before the pouring is started at the other end of the mold. The result of this is that the dull iron traveling toward the spigot endof the mold is carried beyond the center or mid-point almost to the spigot end to be there met by the on-coming hot iron from the second ladle. This second lot of iron livens up the dull iron so that there is a nearly uniform temperature of iron throughout the length of the 1 1 1 Experience as shown this to be the case and also that if the two ladles were poured them at one point. The elimination of surging is important, not only in preventing the washing and accumulatmg of im urities to circumscribed areas of the pipe, ut in the prevention of difierences in thickness in the walls of the pipe at difl'erent points along thelength thereof.

When the mold is revolved, the tendency of the iron is to seek the remotest point on rebounding,

the circumference of the pipe being formed.

The result is that the iron is drawn from the area next to the bell end of the pipe into such bell end because the diameter is there greater than that of the body of the pipe.

If, therefore, all the iron should be poured into the mold before the revolving begins, the resultant pipe would be thinner next to the bell than anywhere else. This difliculty is overcome by holding back a suflicient quantity of molten iron in the ladle at the bell end to form the bell, and after the mold begins revolving, this surplus or withheld iron is emptied into the mold and this final quantity or remnant of iron takes the place of that which has been drawn to fill the bell.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing in the drawings, but may be changed an modified so long as such changes and modi fications mark no material departure from the salient features of the invention as expressed in the appended claims.

In the drawings,

The figure is an elevation, partly in diagram, showing a mold for cast iron pipe and a support therefor on which the mold may be rotated about a longitudinal axis, and in connection with which ladles indivldual to the respective ends of the mold are provided.

Referring to the drawing, there is shown a base 1 which may be considered as a portion of the bases of a battery of centrifugal casting machines. Each machine comprises a head stock 2 and a tail stock 3 carried'by the base or bed 1 and so arranged that a pipe mold 4 provided with head and tail portions 5, 6, respectively, may be mounted between the head and tail stocks and secured thereto in such manner that the mold may be rotated by means of a belt or other suitable power device driving the tail stock 3, which latter may be considered as furnished with a pulley 7 for the application of the belt. Of course, if power e ap lied to the machine in other ways, some ot er driving means than a belt and pulley may be used.

Leading into the head stock 2 is a funnel 8, and leading into the tail stock 3 is a funnel 9, the two funnels communicating with the respective ends of the mold 4.

In order to carry the mold 4 and permit it to be rolled into and out of alinement with the head and tail stocks 2 and 3, respectively, there are track rails 10 which may be common to an entire battery of casting machines or to more than one battery. Associated with the funnel or gate '8 is a tiltable ladle 11 having a manipulating handle 12,and associated with the funnel or gate 9 is another ladle 13 rovided with a manipulating handle 14:. M dlten metal may be delivered to the ladles 11 and 18 by a large ladle 15 which, in an installation for the purpose, would be carried upon a traveling crane, but such crane need not be shown. Moreover, the ladles 11 and 13, in an installation, are carried by suitable supports, which however are not shown in the drawing, permitting these ladles to be tilted by means of the handles 12 and 14 in such manner as to pour their contents into the respective gates 8 and 9.

In practising the method of pouring metal for the production of pipe by the centrifugal process, the mold or flask 4 is placed horizontally in the centrifugal machine between the head and tail stocks 2 and 3 and properly fastened thereto. The two ladles 11' and 13 are supplied with molten metal, the two ladles together carrying enough molten metal to produce a cast iron pipe.

The method may be practised either by hand or in most part automatically. For simplicity of description, however, it will be considered that the ladles are emptied by hand. Such procedure necessitates two operatives, one aving charge of the ladle 11 and the other operative havin charge of the ladle 13. The ladle 11 is tilted so as to pour a portion of its contents, say about half of the contents, into the gate 8 which is located at the bell end of the mold or flask. The metal flows into the bell end of the mold and travels along the latter toward the other or spigot end 0 the mold or flask. About half of the contents of the ladle 11 is thus deposited in the flask and has therefore run nearly to the spigot end of the flask. the ladle 13 is tilted, thus depositing its contents into the flask through the gate 9.

If all the metal were deposited in one end of the flask, it would flow toward the other end until reaching it and then return toward the first end in the form of a wave and this wave might move several times back and forth along the flask, with the result of progressive dulling and sluggishness, until finally, with the flask rotating during the cooling and setting of the metal, an irregular or wavy thickness of the walls of the pipe is roduced.

y pouring the metal into both ends of the flask but not simultaneously, there is produced a flow of metal from one end of the flask, the bell end, to a point near the s igot end before the flow begins from the ladle 13 into the spigot end, so that the metal dulled and slowed up by cooling, though still sensibly hot and fluid, is met by another flow in the opposite direction of hotter metal which livens up the cooling and more sluggish advance end of the first flow, and also retards and turns back such advance portion of the first flow,

thereby preventing the formation at the same time into of a surge which would occur were the first flow to meet the end wall of the mold and rebound. In this way, surging is practically eliminated, and marked differences in temperature at different arts of the metal and mold are prevented. oreover, if the pouring was at one end only of the mold, sand and impurities from the mold and in the iron would be swept toward one end of the mold, or if the pouring was in equal quantities and both ends of the mold, the washing of impurities toward the center of the mold would occur. With the unequal pouring and distribution of metal, impurities are distributed so that no marked accumulations of impurities in segregated areas occur. The simultaneous pouring into op osite ends of the mold causes an even distribution of the metal, prevents surging of the metal, with consequent wavy effect in the walls of the pipe producing thick and .thin ortions, and provides sensibly even distri ution of impurities without accumulation of masses of impurities at isolated points so that the pipe, when finished, is of sensibly even denslty at all points.

'With pipe of difi'erent-diameter at difierent portions of its length, as in the case of bell and spigot cast iron pipe where the bell end is of considerably largerdiameter than the spigot end, the rotationv of the mold causes a greater flow of the molten metal to the bell end which is materially larger in diameter than the body of the pipe. The rotation of the mold, therefore, causes the molten metal to flow outwardly under centrifugal force to the points of greatest diameter and this robs the walls of the pipe immediately adjacent to the bell end, of some of the metal therein, thereby causin a thinning of the walls at such part. or this reason, in pouring the metal from the ladle 11 supplying the "bell end of the mold, the pouring is stopped before quite completed, this withholding in the lad e 11 a quantity of metal suflicient to replenish the bell end of the amount withdrawn therefrom by the the pipe by centrifugal force'and, without rotation of the mold. The procedure of pouring, therefore, consists in pouring about half the contents of the ladle 11 into the bell end of the mold before pouring is started from the ladle 13 into the spigot end of the mold. The pouring then continues from both ladles simultaneously until the ladlell is nearly,

ends of the-mold, the surging of the metal is quickly stilled so that the rotation of the mold may begin promptly, spreading the metal against the inside of the mold to form irregular or wavy portions. As soon as the spreading is completed and before the metal but not quite, emptied while the pouring of the lable 13 is continuous until it is emptied. Because of the non-symmetricalflow of metal from the ladles into opposite has sensibly set, the pouring'from the ladle 11 is resumed until the ladle is completely emptied. The rotation of the mold is continued until the metal has wholly set sufliciently to hold its form.

While it is feasible to practise the method herein described wholly by hand, it is advantageous to employ mechanical means whereby the pouring of the metal from the ladles may be properly timed, irrespective of the volition of the operatives and whereby the number of o 'eratives may be reduced to a minimum. uch means is shown, de-

scribed and claimed in another a plication,

Serial No. 368,170, filed by me on arch 23, 1920, for means for pouring metal .in the formation of cast iron pipe.

- -What is claimed is:

1. The method of casting iron pipe centrifugally in rotatable flasks, which consists in pouring molten metal into one end of the flask, then pouring molten metalsimultaneously into both ends of the flask, then rotating the flask, and then adding molten metal to one end of the" flask while still rotating the latter.

2. The method of casting iron pipe centrifugally in rotatable flasks, which consists in pouring a quantity of molten metal into one end of the flask, then pouring molten metal into both ends of the flask simultaneously, then rotating the flask to cause the molten metal to flow to the outer wall of the interior of the flask, then while the flask is rotating adding more molten 'metal to the interior thereof through one end, and then continuing the rotation of the flask until the metal has set. V

3. The method of casting bell and spigot pipes centrifugally in rotatable flasks, which consists in pouring molten metal to a determined extent into the bell end of the flask while the latter is quiescent, then simultaneously pouring molten metal into both ends of the flask until the supply of metal at the second end of the flask is exhausted and holding back a determined amount of the metal at the first endof the flask, then rotating the flask to cause the deposition of the metal on the inner peripheral wall of the flask by centrifugal force, then pouring into the bell end of the flask metal held back at said end, and then continuing the rotation of the flask until the metal in the flask has set. I 4:. The method of casting iron pipe centrifugally in rotatable flasks, which consists in ouringthe molten metal into opposite on s of the flask with the pouring beginning at one end of the flask in advance of the pouring at the other end of the flask in timed relation to cause the metal of the first pouring to approach one end of the flask ters said secondend of the flask, continuing the pouring at the first end of the flask and completing the pouring at the second end of the flask simultaneously, and stopping the pouring at the first end of the flask when the pouring at the second end of the flask is finished to hold a portion of the metal at the first end of the flask in reserve, then rotating the flask to cause the centrifugal deposition of the metal on the inner wall of the flask, then adding the reserve metal to the interior of the flask, and continuing the rotation of the flask until the metal has set.

5. In the formation of cast iron pipe in horizontal flasks, the method ofpouring the metal into the flask, which consists in pouring the molten metal into the flask from opposite ends thereof, with the pouring into one end of the flask initially preceding the pouring into the other end of the flask and with the pouring then progressing simultaneously.

6 lln the method of casting iron pipe centrifugally in rotatable flasks, pouring molten metal into both ends of the flask, with the pouring into one end of the flask starting before the pouring into the other end of the flask is commenced, and the pouring into the second-named end of the flask being completed before the pouring into the first-named end of the flask is completed.

7. In the method of casting iron pipe centrifugally in rotatable flasks, pouring molten metal into both ends of the flask, with the pouring into one end of the flask starting before the pouring into the other end of the flask is commenced, and the pouring into the second-named end of the flask being completed before the pouring into the first-named end of the flask is completed, and the flask being set into rotation before the pouring into the first-named end of the flask is completed, and the rotation of the flask being continued until the metal there in has set.

8. The method of casting iron pipe cen trifugally in rotatable flasks, which consists in providing supplies of molten metal at the opposite ends of the flask, pouring metal from the supply atone end until approximately half the supply has beenpoured, then pouring metal into the other end of the flask from the second supply until said second supply is exhausted, with the pouring from the first supply continuing with a relatively small quantity of the first supply held back, then rotating the flask to centrifugally deposit the molten metal on the outer wall of the mold cavity, then pouring the remainder of the first supply into the mold, and then continuing the rotation of the mold until the metal has set,

In testimony that I claim the foregoing as my own I have hereto affixed my signaturec JAMES R. MGWANE.

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