US1776540A - Rotary casting apparatus - Google Patents

Description

Sept. 23,*1930. F. G. CARRINGTON 1,776,540

ROTARY CASTING APPARATI'JS Filed Feb. 24, 1927 3 Sheets-Sheet l Sept. 23, 1930. F, G. CARRINGTON ROTARY CASTING APPARATUS Filed Feb. 24, 1927 3 Sheets-Sheet 2 Sept. 23, 1930. F. G. CARRINGTQN ROTARY CASTING APPARATUS Filed Feb. 24, 1927 3 Sheets-Sheet Fra/d 0 WM a ma i W. ,e G a 6.. F.

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Patented Sept. 23, 1930 UNITED STATES PATENT oFFlcE FRANK G. CARRINGTON, OF ANNISTON, ALABAMA., ABSIGNOB TO FEBBIC `IFJN'GINIIIEB- IN G COMPANY, OF ANNISTON, ALABAMA,

A CORPORATION OF DELAWARE ROTARY CASTING APPARATUS Application inea February 24, 1927. sum1 Na. 170,547.

This invention relates to an apparatusfor centrifugally casting pipe, and more artlcularly refers to a trough construction or conv veying molten metal to a mold and distributing the metal therein.

Casting annular metal objects by the centrifugal, or rotary, process involves the discharge of metal in a revolving mold. The three types of molds commonly used, whlch necessitate'different apparatus and variations in the process, are: (l) those in which the metal is poured just inside the end of the vmold and the metal is distributed longitudinally by manipulation of the mold; (2) those in which the metal is poured over the side of a so-called dump type trough which is rotated upon its longitudinal axis and (3) those in which the metal is discharged from the end of a. trough over which the mold telescopes.

This invention falls into the type of machine in which the metal is deposited from the end of a trough. By avoiding the time-consuming distribution of the metal while in contact with the mold inequalities and defects in the castings are avoided and mold materials of greater heat-conductivity may be used.

Because of the relative motion of the trough with respect to the mold, and because the metal is distributed at one terminal of the trough by means of a spout attached thereto for evenly distributing the metal, the trough can be supported at one end only.A This warping of the trough, both horizontally and vertically has been one of the serious problems confronting the industry. The dierential heating of the trough is due to hot molten material being poured therein together with the weight of the molten material tending to cause warpage of the trough.

AsA the molten metal is at a very high temperature, it is necessary to line the trough. Another difficulty experienced bythe indus- .try has resided in a tendency for this lining to warp. The Warpage in this instance, however, is upward, and, when occuring in conjunction with a drooping of theV trough casing, there is a space between the trough and lining which makes for inaccuracy in the amount and direction from the trough.

An object of this invention is to devise a method of preventing sagging of a trough supported at one end onl Another object of thls invention is a method of preventing warpa e of a, lining for a hot fluid conducting troug,

A further object of this invention is to provide a non-sagging trough supported at only one end.

Another object of this invention is to provide a trough with means for preventing horizontal warping of the trough.

Yet another object of this invention is to provide a spout for attachment to a liquid conveying trough.

A still further object is to provide a linin for a trough conveying hot liquids witg means to prevent warpage of said lining.

With these and other lmportant objects in view, as will more fully hereinafter appear, my invention consists in a trough apparatus comprising a casing with means for checking the expansion of the upper portion 'more than the lower portion, and preventing horizontalwarpage ofthe casing, a lining .mounted in said trough to permit separate expansion of the trough and 'lining and of such construction that there may be a relative expansion of the bottom portion independent of the top, and a spout for distributing the liquid in the mold.

In the accompanying drawings in which similar numerals indicate corresponding parts of the trough,

Figure 1 is a broken away side view of the complete trough, partly in elevation and partly in section;

' Fig. 2 is a top plan view of a section of the trough with a continuous lining near its termination;

Fig. 3 is a cross sectional view of the trough of metal `discharged.

. and lining along the line 3-3 of Fig. 2, look- .line 5-5 of Fig. 1, looking in the direction indicated by'the arrows;

Fig. 6 is a longit-udinal View of the casing and llning, showing anoptional form of Jomin the sections of the lining;

ig. 7 is a view in longitudmal section of the casing and lining showing another method of joining sections;

Fig. 8 isa front elevational view of a spout; Fig. 9 is a top view of a portion of the trough with a modiiied form of lining;

v Fig. 10 is a sectional View of the trough shown in Fig. 9, along the line 10-10, looking in the direction of the arrows.;

Fig. 11 is a view in cross section of Fig. 9, along the line 11-11, looking in the direction of the arrows;

Fig. 12 is a cross sectional view of a trough showing an optional shape.

Referring to the accompanying drawings but in no wise limiting the scope of this invention to the particular embodiment therein set forth, there is shown in Fig. 1 a trough construction comprising a casing or support member, the shell 1 of which is partially cylindrical in cross section, and cooling means mounted in the casing. The shape of the shell may be modied as shown in Fig.

12. The cooling means set forth in Fig. 1 are those mounted in only one side of the casing, and, as will appear in Fig. 8. similar means are provided for the other side. lThese.

means comprise a pipe 2, or other suitable channel, formed in the upperportion of they 4 positioned below and extending tothe bottom portion of the casing. It will be noted that the chamber 4 is practically co-extensive with, although of larger cross section than, the pipe. The shell extends beyond the cooling system and lining, as at 5.

The cooling medium is introduced to the casing by means of the pipe 6, and its rate of flow regulated by the valve 7 which may be a pressure regulating valve. A similar pipe and valve are provided for the cooling channel formed in the other side of the trough. An outlet pipe is connected `with the chamber 4, as at 8, although it may be positioned at any point beyond the portion of the trough to be cooled. The cooling medium passes through the pipe 2, the connecting pipe 3, and then into the chamber 4' where it is finally discharged at 8. As the medium passes along this path. its temperature is increased by heat exchange with the molten metal. There will be differential temperatures of the fluid between any two points in its course and the medium will be of considerably higher temperature in the chamber 4 than in the pipe 2. This is due to the fact that the medium in compartment 4 has been exposed to the heat of the trough and molten metal for a longer period than the medium i-n pipe 2, and is also a. result of a. more eiective heat exchange between the molten metal and medium in 4 than is the case with the medium in 2.

It will therefore result that there is a less tendency for expansion of the upper portion of the trough than of the bottom. When the casing sags there is established in the upper portion a tension and in the lower portion of the casing a compression. The differentials in temperature between the upper and lower channels therefore counteract the stress set up as the casing sags.

There is also shown in Fig. 1 a conventional chute 9 into which the molten metal may be poured and which directs the metal thus received into the channel of the trough. This' chute may be dispensed with if it is desired to pour the metal directly into the trough, but such a method is not advisable because the chute obviates any loss of the metal in the pouring and minimizes splashing. v f

The main portion of the casing terminates at 10 but there is a prolongation of the shell to 11. lnto this prolongation there is fitted a spout 12, having a channel whichslants downwardly as indicated by the dotted lines 13, and provided with a reduced extension for projection into the shell 5. The spout is secured in the shell by the screws 14 or other suitable means.

The chute and the spout may be considered as portions of the lining, in that they may expand independently of the trough casing. They may be formed integral with the lining or attached thereto by any of the means, described later, by which the lining sections are connected.

As shown in Fig. 2, the trough is lined with appropriate material, preferably cast iron, although certain grades of steel. such as chromium steel, may be used. The lining 15 is of the same coniiguration as the channel lof the support member or casing, and

along its length there are regularly and opposhown in Fig. 2 is made from one continuous strip of material, and in such case the slots may be cut outof the lining or may be made by merely sawing from the topv to the point 17. As the bottom of the channel is in contact with the molten metal,'it will be exposed to greater heat than the top. With this difference in temperature there will be an attendant diiierence in expansion of the lining, and, in the absence of some such pro-- vision as herein made, this differential expansion will cause the lining to warp upwardly. The slots herein set Jforth will permit the expansion of the bottom portion of vtion, and in this way will prevent warpage.

It is, of course,'to be understood that these slots may be made in any suitable manner, and,under certain circumstances, may be in some relation other than that here set forthas for instance, they may be irregularly placed, or positioned in a staggerrelationship, or they may slant rather than descend perpendicularly. Hereafter there will be discussed certain modifications of this lining construction.

It is also to be understood that the purpose of these slots is to limit contact between relatively short sections of the linin to areas of uniform temperature. When t ese areas are those of the highest temperature, and therefore along the line of greatest expansion, the space between the unattached areas of the liner section faces will become greater as the temperature difference over the liner increases and less as this temperature difference approaches uniformity. Should the contact areas ,not be located in the line of greatest expansion, the unconnected portions of theliner faces which are' of higher temperature than the connecting areas will decrease the slot widths as the temperature difference increases. 4

The effect ofthe slots may therefore be defined as permitting unrestricted lineal expa'nsion of the lining while limiting the Iwarping effect of temperature differentials to such short lengths that the warping in each will be negligible. j The positive connection between liner sections is to cause the lining to contract as a whole during periods of decreasing temperature. The Adrawings and above description refer largely to avoiding vertlcal warping. Horizontal warping is .prohibited by locating the contact areas so that no horizontal stresses will appear or -so that the slots will compensate for them as for verf tical warping. Slight horizontal stresses also do not become apparent because the lining is held in line by standards of the trough.

The slot widths, are kept small to prevent the entrance of molten iron therein. Where the section faces are joined by bolts or welding, Fig. 6 and Fig. 7 and described later, no slots are necessary at normal temperatures, when the bonding material is elastic or where the bond is made in the region of greatest ex-` pansion. In this case the expansion 'stresses will be absorbed bythe elastlc materla-l, or

spaces will appear between the unconnected portions of the faces as the 'expansion differentials arise.

In order to allow creeping of the lining, attachment of the lining is made at only one point, or at points suliciently close together so that the difference in expansion of the trough and the lining will not be a parent.

' Hereafter when mention is made o attaching the lining at only one point, the term is used with thisy meanin The point at' which the lining is attac ed is preferably adjacent to the spout.4 There will then be no expansion toward the spout, all creeping of the lining necessarily being in the opposite direction, and consequently no tendency for the expanded lining to force the spout from contactual alignment with the trough. The lining of .the casin terminates at 10, and lugs, or other suitabv e fastening means," pass through the lining into the casmg, as shown diagrammaticall at 18, to anchor the lining at that point. obtained by insertin the lugs at the top of the lining than at ie bottom, for there is minimized the strain placed upon the fastening means. v

n Fig. 3 a semi-cylindrical casing is shown. StandardsA 19 vextend from the top of the casing and converge toward the bottom, forming a channel into which the lining 15 fits. The inner faces of the standards form sides of the chamber 4. It will be observed that the chambers extend considerably below the channelof the lining. Above the chamber 4 are the channels 2. Channels 2 may be formed by drilling a hole in the casing, or

. the casing may be formed with recesses, and

plates 21 welded, brazed, or otherwise suitably secured, in the casing, which plates will serve to separate the channel .2 from the channel 4. As the lower chambers are larger than chambers 2, there is a slower rate of flow, which constitutes another `factor in maintaining a higher temperature ,of the cooling medium in the lower compartments than exists in 2.

Horizontal warping of the trough may be prevented by regulating the temperature of the coolin medium introduced to each side of the casing, so that expansion or contraction can be oli'set by the variance in tempel'- atire of the cooling medium in the respective s1 es.

There is a slight bulge in the Wall of the casing, as at 22, which serves to maintain the lining`in position. The lining, it will be noted, because of its configura-tion and that of the channel of the casing into which it fits, must be inserted from one end, and because of the protuberance 22, is incapable of vertical movement with respect to the casing. But as hereinbefore stated, the lining may move longitudinally of the casing in order to prevent warpage.

Lips may be formed on the casing, as at 23, in Fig. 4, to provide additional means for more secure attachment is A SII retaining the lining in the trough. These, I

mold which it must enter, the shape and sizev of the parts of the trough are somewhat fixed.

The shape of the stream in the liners isdeeper and narrower than is best suited for depositing the metal against the mold. The s out 12 ispan uncooled extension of the troug with the same limiting outside dimensions as the trough casing, but, becausey no space is required for the cooling chambers, greater latitude is permitted as to the sha-pel of the channel. This channel is the same shape as the channel of the liners, where the spout. 12 contacts with the liners, but may broaden as shown in Fig. 8 and may also cut lower than is practical in the liners, as at 13-Fig. 1,` in, yorder to decrease the distance through which the metal must fall from the spout to 'the mold. The spout 12 is attached to the casingA in the sleeve beyond the cooling chambers by the pins 14 as shown in Fig. 5. l

The spout 12 is designed to minimize the splashing in distributing the material in 'the mold. This is of considerable importance in the process of casting with a metal mold because the molten metal is subjected to a rapid cooling. Consequently, if drops of the 9 splashed metal fall upon a portion of the dev posited metal that has cooled, or if itk falls upon the surface of the mold not yet covered with metal, there will result excrescences or defects in the casted object. The `method. of

attachment and theshape of the spout channel prevent the lodgment of any portion of the molten metal in the spout or at its junction with the trough, and insures that all of the Ametal is distributed in the mold. By making the spout separately detachable from the trough, replacements of the spout vmay be made in the event of its breakage or warpage.

It is not necessary that the lining be made of one piece, for it may be composed of any` desired number of sections, either coinciding with the slots 16 or terminating in multiples thereof. If a sectional lining is employed, the

joinder of the sections may be by welding or bolts.

Should the sections be welded together, as in Fig. 6, they may be of the Ageneral configuration of a continuous lining without slots. In this case the slots might be formedk by welding the sections at the bottom, as at 24, and extending-the welding to the desired height, 17, on the side walls. Those portions of the ends'that are not welded therefore would form the sides of the slots, andthe depth and width of the slots would depend upon the extent of the welding.

Should it be desired to join the sections by means of bolts, there is shown in Fig. 7 a form for such a lining. In this case the 'sections are formed as in Fig. 6, with the exception that slight shoulder extensions 25 are provided at the bottom of the sections and the extent of which depend upon the size of slots desired. When the sections are then placed in alignment, the shoulders 25 will alone contact, the remainder of the section ends 26 formin the slots. There are recesses 27 in the base o the sections and apertures 28 corresponding to similar apertures in the other sections. A bolt 29 is placed in the aperture and fastened by means of a nut 30. y

The apertures and bolts may be rectangular to prevent rotation of the bolts. When properly adjusted the entirev lining will be in alignment and ready for insertion in the casing.` The bolts are of such length that the difference in expansion between the bolts and the .lining will be practically negligible. l

In Fig. 8 there 1s shown the channel of the spout. As before stated, the absence ofcooling means in the spout permits an enlargement of its 'channe It slants both downwardly and to the sides, pouring the metal in more nearly a flat sheet, and with less resulting splash. The channel of the trough lining at its termination is indicated at 31, 'from which the'spouts channel slants away to its termination indicated by 32. It is to be observed that suliicient materialis left between the channel and the casing to give the spout proper sup ort. The dotted lines 2 and 4 represent t e cooling systems mounted in each side of the trough. The pipes' and valves 7 for supplying the respective systems with a cooling medium are also shown. t

The lining shown in Fig. 9 may be adopted in lieu of the form shown in the other figures. Instead of having the slots merely at the top of the lining, there are also provided slots at the bottom as at 33. The connecting portions 34 are on the sides of the lining rather than at the base. As there is a greater variation in expansion of the lining at the base than elsewhere, the presence of slots at that portion permits dierential expansion without warping the lining.

In Fig. 10 there is shown a longitudinal sectional view of the lining with slots'33 eX- tending upwardly from the bottom and opposite the slots 16. Under certain circumstances the slots may be in some arrangeo5 of the trough is counteracted.

p bond is to be avoided. variation there will cause vWarpage whereas variation along the slots will mere y result in varying the width `of the slots.

- While Figs. 9, lOand 11 indicate acontinuous lining slotted, it is to be understood ance is decreased. The sides of the casing are partially cylindricahwhile the base is,

flat as at 35.

Pipes are not em loyed in this form of trough, although un er certain circumstances the channel of the lining may be of substantially V-shape, as in the other type of trough.`

As the molten metal passes through the trough channel both the lining andsupport member are heated. y The lining is, of course, heated the most at the bottom where'there is a more direct contact with the metal. As

more rapidly than the top, causing, in the absence of counteractingv means, an upward curling. This inventionprevents such a result, for the slots in the lining permit a greater expansion at the bottomv than at the top. As the lining is fastened to thetrough at only the end adjacent the spout, the expansion is in nowise hindered and the creepmg that ensues is away from the spout.

Ordinarily the weight of the trough, and

its lack of support for that portion extending -within the mold, causes a sagging, as previously mentioned, seriously interfering with the eiiicient operation o'f the process, unless suitable preventive steps are taken. The tenl sion in the upper portion and compression of the bottom of the trough, established by the sagging, are compensated for in this invention by the arrangement of the channel for the cooling medium. The difference in temperature of the cooling mediumin the upper andlower conduits checks the expansion of the top and thus the saggin tendency he spout loyed, such as is shown in ig. 12. It will horizontally than td ance is permitted, while the horizontal clear-v pipes may be substituted for the chambers a consequence the lower portion expands .mcrease the operatlng costs.

serves to maintain the Asaine rate and volumeof fiow as prevails in the trough, while causing the stream to vchange to a moredesirable shapel atthe discharge end. The provision for quick and easy replacement of the s ut curtails the loss of time ordinarily atteniint in making repairs to such an apparatus.

One of the prima considerations in the art of centrifuga casting is assurance that the metalis distributed in the mold at a given rate and in a certain liquid state. The provisions of this invention, with the elimination of any possible obstruction and cause of hindering the flow of metal insures a con-l stant fiow. As the uidity o molten metal depends upon its temperature, a variation in the time required for the metal to pass from the ladle to the mold means a variance in its .liquid state. Warpage of the lining or sag in the casing therefore would change therate of flow and consequentl vary the fiuidity of the metal at its distri ution inthe mold. Protrusion or cavities thatv might -effect a lodgment for the metal en route are, of course, to be avoided also, forveven a temporary delay of part of the metal will mean a portion, at the time of distributionin the mold,vary. ing from the iiuidity of the rest of the metal, and a consequent premature cooling. This will cause fiaws in the casted object. yThis invention, it is believed, overcomes the difliculties just enumerated. The non-warping lining, non-sagging trough, and the spout provided all tend to insure a constant, uninterrupted, and even temperaturediow of metal.

It isv perhaps needless to advert to .the labor and money saving features of this invention. -Suiice it to say that lin such a process, with the large amount of capital invested, temporary delays in operation greatly The facility with which the parts of this invention may be substituted or replaced greatly decreases the amount of time lostin making repairs.

` While I have shown and described. the pre ferred embodiment of my invention, I wish it to be understood that I do not confine` myself to the precise vdetails of constructionv a support member, and a continuous lining. mounted therein, and secured thereto at onel point only. v 2. A lining for a Ametal conveying trough with transverse recesses at the top of said linin 4 3. In a. trough forpourmg metal, a continuous lining having oppositely disposed lll and axially erpendicular slots extending downwardly rom the top ofthe lining to mediate points of the sides.

4. An end pouring trough in a rotary casting device comprising a casing, a lining, and means for maintaining a lining inthe channel of the trough, while permittlng independent expansion of the casing and lming.

5. In a trough for pouring hot liquids, a casting adapted to cool the top at a rate different from that at which the base is cooled.

6. A metal conveying trough for a rotary casting apparatus, comprising a sup ort member with a conduit for a cooling me um at the top and another conduit'for a cooling medium at the bottom, said conduits being in metallic contact with the su port member, and'adapted to cool the top of) the trough at a greater rate than the base.

f 7. A support member for-a trough comprising a casing, a chamber near the top for the receipt of a cooling fluid and the conduction thereof substantially the length of the support member, and a larger chamber in the bottom of the support member connected with said rst mentioned chamber, and adapted to cool the top of the trough at a greater rate than the base.

8. An end pouring trough in a centrifugal casting apparatus comprising, a casing of partially cylindrical shape having a longitudinal channel, conduits for a cooling liquidv in the top of thecasing and larger conduits positioned in the bottom of the casing to receive the liquid after its How through the first mentioned conduits.

9. A casing for a trough in a centrifugal,

casting apparatus comprising a partially cylindrical shell, members forming a longitudinal channel substantially the length lof the shell adapted to receive a lining, protuberances on the said members for maintaining the lining in the channel, another channel substantially co-extensive with the first mentioned channel and positioned in the upper portion of the casing for the conveyance of a cooling liquid, a larger'chamber 1n the bottom of the casing connected at one terminus with the second mentioned channel for conveying the liquid inthe opposite direction to the ilow in the second mentioned connected at one terminus with the second mentioned channel and an outlet pipe at the opposite terminus of the chamber.

11. A pouring trough comprising a casing with arcuate sides and straight base, standards extending from the top of the sides to the intersection of the sides and base, horied to creep with respect to said support member. 1

13. In a centrifugal casting apparatus, a trough comprising a support member with conduits for a cooling medium positioned in its upper portion 'and chambers in its lower portion for receiving said cooling medium, a lining for saidsupport member attached thereto at one Apoint only, a chute and a spout attached thereto.

14. A trough in a rotary casting apparatus,comprising a partially cylindrical support member, independent conduits in the upper portion extending substantially the length thereof for conveying a cooling Ine- Adium, independent longitudinal chambers positioned in the lower portion of the support member and connected to said first mentioned conduits, a lining secured to said support member at only one point having axially perpendicular slots extending downwardly from its upper edges, a chute for conveying molten metal to the trough, and a spout attached to the discharge end of the trough.

15. A trough for relative longitudinal movement with respect to a mold for cen,- trifugal casting, comprising a casing of frusto-cylindrical shape, standards from the top of the casing forming-a. substantially V-shaped channel adapted to receive a lining, protuberances on the standards corresponding to recesses in the lining for retaining the latter in the channel, lips on the casing overhanging the lining, chambers for conducting a cooling liquid positioned near theV intersections of the standards with the top of the casing, pipes near the'discharge end of the trough connecting the said chambers with independent larger chambers lin the lower portion of the trough, means for independently varying the temperatures lof the media introduced -to said up er chambers, an elongation of the casing s ell; a lining for the channel formed by the standards having slots perpendicular to its longitudi- -nal axis extending from the top of said lining to mediate points on the sides, said 1iningl being attached to the channel at only the discharge end of said casing, a. chute at 'the receiving end of the trough for direct- 5 ing the liquid into the channel and an 11ncooled spout having an enlarged channel.

In testimon whereof I affix mIy signature.

F ANK G. CARR NGTON.

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