US3381073A - Process for casting articles - Google Patents

Description

April 1968 E. BRICHARD ETAL 3,381,073

PROCESS FOR CASTING ARTICLES Filed July 21, 1965 5 Sheets-sheet l- ADOLPHE DUPONT JEgliy DE KEERSMAECKER APT;l 1968 E. BRICHARD ETAL 3,381,073

PROCESS FOR CASTING ARTICLES Filed July 21, 1965 5 Sheets-Sheet 2 EDGARD BR/CHARD ADOLPHE DUPONT JEAN 0E KEERSMAECKER wwgcw April 1968 E. BRICHARD ETAL 3,381,073

I PROCESS FOR CASTING ARTICLES Filed July 21, 1965 5 Sheets-Sheet 5 /N VE N 70/25 EDGAR!) ERIC/MRO ADOLP DUPGN'T JEAN KEERSMAECKER 1 ATTORNEY United States Patent 3,381,073 PROCESS FGR CASTiNG ARTECLES Edgard Brichard, Jumet, Adolphe Dupont, Marcinelle,

and Jean De Keersmaecker, Couillet, Belgium, assignors to Glaver'oel, Watermael-Boitsfort, Belgium, 2 Belgian company Continuation-impart of application Ser. No. 206,984, July 2, 1962. This application July 21, 1965, Ser. No. 473,870 Claims priority, application Belgium, July 4, 1951,

7 Claims. (Cl. 264-454) This application is a continuation-in-part of our application Ser. No. 206,984, filed July 2, 1962.

The invention disclosed herein relates to improvements in the production of articles by casting and is especially advantageous in connection with the casting of articles having openings or passages therein such as wheels with hubs, wheel shafts, cylinders for rolling mills, draw bars used in the manufacture of glass sheets, etc.

The existing processes for casting refractory materials which are fusible at high temperature by known igneous methods to produce articles of large size and height and especially those of complex form, have a number of disadvantages. Usually, the molten refractory material to be cast in making such articles is poured directly into the mold at one or more points and the articles are hereafter removed from the mold. In the practice of this method, the molten refractory liquid falling to the bottom of the mold causes an appreciable erosion of the bottom of the mold, especially if the pouring takes place from a fairly considerable height, owing to the shape of the article to be cast. On the other hand, the material first poured into the mold readily splashes, .and the greater part of the splashed material adheres to the walls of the mold and becomes congealed thereon, so that the subsequent welding between these drops and the mass of the article will be poor and even non-existent. In any event, the surface appearance of the article will be bad. Also the uncontrolled agitation which occurs in the mold during the pouring operation causes the inclusion of large quantities of gas and the formation of cavities in the cast article. Further, the casting of articles of complicated form by such refractory materials is generally difiicult to perform. Usually in forming such articles with materials which are fused with difiiculty, shrinkage holes of substantial size are created and often require the cutting away of the entire upper portion of the casting which is waste. For example, it has been found in the manufacture of draw bars which are used immersed in glass melting tanks and which may have a length of 350 cm., a width of 50 cm., and a thickness of 30 cm., that it has been necessary to first cast the draw bar to a thickness of 60 cm. and then cut it at mid-thickness in order to eliminate the superficial shrinkage hole. In an effort to overcome the aforesaid disadvtantages in casting articles of the type indicated, attempts have been made, to use molds comprising in their lower part one or more channels through which the liquid material is introduced. Such a system will eliminate the disadvantages of direct pouring, but it necessitates specially adapted molds and does not correct the other aforesaid disadvantages.

The process of the present invention afi'ords the advantage that it enables the employment of ordinary molds and the pouring of the liquid refractory material into them with the simplicity of direct casting, while eliminating the aforesaid disadvantages. More particularly the invention makes it possible to eliminate large cavities in the casting and to supply a product having a better appearance and greater homogeneity in regard to the composition of its mass. Moreover, the invention makes it possible to localize the portions of the castings to be dis- 'ice carded, to reduce erosion or deterioration of the molds, and to produce more readily articles of complicated form.

In accordance with the invention, the refractory material in the molten state which is to be cast is distributed within the mold at a level situated between the bottom of the latter and its upper portion through at least one feeding column or device that is independent of the mold. The liquid refractory material is advantageously initially distributed within the mold in the neighborhood of the bottom of the latter, but the point of distribution may be displaced in the course of the pouring or multiple distribution points may be created, which become effective as the level of the material in the mold rises.

To accomplish the aforesaid results, the device according to the invention is constituted of one unitary feed column which is independent of the mold, and which has a bottom orifice that is located within the mold at the given level chosen for the initial distribution of the particular refractory liquid material to be cast. The device extends from such given level to a point located outside of the mold so that the molten material is poured into the col umn or device through the end thereof situated outside the mold. The distribution column may be provided with lateral orifices through which the liquid material is discharged into the mold as the level of the liquid in the latter and in the column rises. To prevent any possibility of violent contact of the liquid with the bottom of the mold, which might cause erosion of the latter, there is advantageously provided at the bottom of the column below the bottom orifice thereof means for breaking the stream of poured material. When a column having lateral apertures is employed, it may be desirable to adjust the position of the stream-breaking means in such manner as to constrict the lower passage of the liquid and to increase its flow through the lateral orifices.

The feed column is constructed either of a material identical to the liquid refractory material being cast or of a mate-rial weldable therewith, or of a refractory material which is fusible at a temperature below the casting temperature of the liquid material if it is desired that the point of distribution of the material should closely follow the rising level of the cast material. A better understanding of the invention will be obtained from a perusal of the following description which should be read in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic vertical section showing a mold provided with a feed column made in accordance with the invention;

FIG. 2 is a similar view showing a form of feed column in enlarged scale;

FIG. 3 is a view similar to FIG. 2 showin a modified form of column;

FIG. 4 is a view similar to FIG. 1 showing another embodiment of the invention in a mold;

FIG. 5 is a partial vertical sectional view illustrating the manner in which the feed column may be employed in casting a wheel with a hub;

FIG. 6 is an elevational view partly in section to illustrate the manner in which a draw bar for making glass sheets may be cast;

FIG. 7 is a broken side elevational view of the cast draw bar;

FIG. 8 is a transverse section of the draw bar taken along the line 8-8 of FIG. 6; and

FIGS. 9, l0 and 11 are vertical sectional views illustrating the manner in which the casting of FIG. 5 is completed.

The constructional form illustrated in FIG. 1 of the drawings comprises a column 1, which is vertically disposed within a mold 2 consisting of walls 3, a base 4 and a cover 4'. The column 1 is mounted directly on the base 4 being supported in spaced relation therefrom by a plurality of legs 5 secured to the bottom of such column. The legs 5 are of a selected length to maintain the lower or bottom orifice 6 of the column at a given appropriate distance from the base 4. The liquid refractory material 7 to be cast is poured into the column 1 through the upper orifice 8 thereof, which is flared in the form of a funnel and is situated outside the mold.

As has been previously stated, the column 1 may consist of a material of the same nature as the article to be cast, or of a material weldable to the material of said article, or of a material which is fusible at the casting temperature. As the invention is particularly concerned with the casting of refractory materials which are fusible at high temperatures by igneous methods known to the art, such as metals, metal alloys, ceramics and the like, it has been found that metals, mixtures and alloys of metals, and refractory chemical compounds such as oxides, silicates, and particularly those compounds poured in electromolten form when their melting point exceeds 2000 C., are best suited for the construction of the column or pouring device 1. Materials which have been found suitable for the construction of the device 1 include among the metals the following:

Melting points, C.

Aluminum 660 Antimony 630 Chromium 1930 Copper 1083 Gold 1063 Iron 1535 Lead 327 Manganese 1220 Nickel 1455 Platinum 1773 The following alloys have also been found suitable:

Melting points, C.

20% lead, 80% silver 840 10% copper, 90% aluminum 630 40% nickel, 60% tin 1305 gold, 80% platinum 1610 90% copper, 10% aluminum 1055 Other suitable alloys or metallic compounds which have been found suitable include all forms of steel, cast iron, steels alloyed with manganese, chrome and nickel, for example, the alloy composed of Fe 70%, Mn 1%, C .05 P-l-S .05%, Si 1%, Cr 18% and Ni 9% and triple alloys such as Cu-Sn-Pb and Ag-Au-Zn.

Following are some of the ceramic refractory materials which have been found suitable for the purposes of the invention:

As previously indicated the material to be selected for the construction of the column or device 1 depends on whether the device is to be left in the cast piece as an integral part thereof either in a dispersed or stable form, or whether it is to be employed to feed the molten refractory material into the mold at selectively chosen levels or levels to accomplish a specific result, such as, the elimination of shrinkage holes in the cooled casting.

If the difference in temperature between the material to be poured and the melting point of the column is small 4 the latter will not melt and after cooling will remain either welded to the poured (cast) material or hooped by the latter. If the difference is high, the column will melt during the pouring at a rate depending on its thickness and it will disseminate itself in the mass as the pouring level is raised. These small or great differences in temperatures may be utilized to accomplish the results desired Whether the material to be poured and the material of the column are identical or different; the only limitation is that one cannot maintain a small difierence if the material to be poured melts at a temperature much higher than the melting point of the column.

If the material of the column is easily fusible, it will be dispersed in the mass during the pouring operation thereby making it possible to form alloy steels, or killed metal bodies or steels by means of a column of aluminum for example, or to adjust the final content of a cast metal by a column containing a fusible additive. For example, in casting a piece to be constituted of an aluminunncopper alloy, one can pour the copper at a temperature of 1200 C. through an aluminum column melting at 660 C. The column will melt dispersing itself throughout the copper and thus produce the alloy desired. At the same time one will have accomplished the purposes of the invention, namely the avoidance of spattering, shrinkage holes, etc. In this connection it will be noted that if the pouring temperature is greater than the melting temperature of the column, the latter will melt with a certain lag, which will facilitate the filling of the shrinkage holes at the same time as the material of the column is being dispersed throughout the poured mass. If the column is not fusible, it will remain in the casting, for example in a condition of a form of boss, which can be machined subsequently, or in the form of a shaft such as the shaft of wheel and the axis cylinder of a rolling mill, or as an inner wall of the cast piece, such as the inner wall of a sleeve. When the column 1 is made of infusible material it is preferably provided with lateral orifices, which are larger at the location of the shrinkage hole as will hereinafter be further described. After cooling, this column will be integral with the casting either by reason of its being intimately welded to the latter, or being hooped, that is clamped in by the contraction of the material of the casting. One has thus been able to cast aluminum wheels (poured at 800 C.) in a copper bushing. After cooling, the inner aluminum core is removed from the bushing and the bushing bored to the desired diameter. There is thus obtained a hub perfectly hooped by the wheel, or perfectly bored and smooth bearing surface, without deformation, while the shrinkage hole in the aluminum was eliminated.

It will be understood from the foregoing that the form of column 1 is important in controlling the violence of the stream of molten refractory material being poured into the mold in order to prevent erosion of the bottom wall of the mold and spattering on the side walls thereof. Thus the upper portion of the column 1 should preferably include above the orifice 8 a funnel-shaped portion 12 capable of enabling the molten refractive material being poured to fall on the inner wall of the column 1 as is shown in FIG. 1 of the drawings if the diameter of the column 1 is large and thereby break the downward force of the column. The column itself may function to dampen the violence of the stream by making its diameter small, in which case the funnel-shaped upper portion 18 (FIG. 2) thereof should be made large enough or configured to avoid loss of the molten material as it is being fed into the upper orifice 8' of the small column, as is indicated by the portion 12' shown in FIG. 4 of the drawings. The column may also comprise below its lower orifice 6 streambreaking means, such as the disc 9 shown in FIG. 2 secured to the legs 5. The disc 9 may advantageously consist of a fusible material, so that it disappears as soon as the layer of cast material on the base is sufiicient to protect the latter from erosion.

The column 1 may also be formed to effect feeding of the molten material to selectively chosen levels in the mold by providing the column with lateral feed orifices (FIGURE 3) in the part thereof situated within the mold. These orifices 10 are made substantially larger at the places where the shrinkage holes would tend to appear in a particular casting as is indicated by the orifices 10' in FIG. 3 of the drawings. As previously indicated the prevention of large shrinkage holes may also be accomplished by increasing the height of the charge in the column at the time that these shrinkage holes would be formed. This may also be accomplished by constructing the column so that there is a delayed fusion of the column near the shrinkage hole points such as by providing the fusible column with an excess thickness at the place of localizing of the shrinkage holes as indicated by the portion 13 of the column 1' illustrated in FIG. 4, or by forming the column with a material having a negative coefficient of expansion, such as bismuth, which upon cooling will fill up the shrinkage hole. When the column is provided with orifices 10 and 10' and particularly when the stream breaking disc 9 does not consist of fusible material, it is advantageous to reduce the distance between the said disc and the lower orifice 6 to a value such as to favor the flow through the orifices 13 and it), in proportion as the level of the material in the mold and the column rises. In addition, in order to prevent splashing or" liquid material against the walls of the mold through the orifices 1t), 10' which the level of material has not yet reached, it may be desirable to orient these orifices horizontally, or to incline them towards the interior of the column as illustrated in FIGURE 3. Moreover, that portion of the column which is situated outside the mold may be surrounded by a heat-insulating material 11.

The construction shown in FIG. 4 of the drawings may also be provided with lateral passages 14 and these are preferably larger at the place where the shrinkage holes are likely to appear in the casting, as above explained. When the article has been removed from the mold, it is sufiicient to remove the thin wall 15 remaining at the position of the legs 5, which are advantageously of short length. This wall may be avoided by disposing the column directly on the base of the mold, and in this case the molten material is fed into the mold solely through the lateral orifices 14.

It may be advantageous, for example in the case of articles of special shape, to move the feed column during the casting. The feed column may readily be horizontally, vertically or obliquely displaced by means of a known device, for example by suspending the column from a small electric tackle arranged to travel along an orientable rail. For vertical movement, the column may also be suspended from a fixed point and the mold may be mounted on a support adapted to be lowered at a controllable speed.

FIG. 5 of the drawings illustrates the manner in which the invention may be employed to cast a wheel with a hub. For the purposes of illustration the wheel is made of aluminum and the hub 21 is made of copper. The hub 21 initially was an integral part of a tubular column made of copper and composed an upper fiared, funnel-like portion 22, a body portion 23 of which such hub 21 was a part, and a lower portion 24 provided With lateral openings 25 through which the molten aluminum poured into the feed column discharged into the space in the sand mold 26 in which is formed the wheel 20. The line 27 indicates the symmetry axis of the assembly which may have an overall diameter of 25 cm., and the line 28 indicates that the portion of the wheel 20 below such line and the lower portion 24 of the feed column may be cut away after removal of the casting from the mold. The upper portion of the feed column is cut away along the line 29 after the casting has been made. The cast material remaining in the column after the casting operation may be removed therefrom in any convenient manner, for instance, by blowing, hammering, boring, or the like. These steps are illustrated more clearly in FIGS. 9 to 11 of the drawings. FIG. 9 shows the body portion 23 of the guide column in the mold after the pouring has been completed and the parts cooled. The guiding column is shown provided with enlarged orifices 10" at the place where the shrinkage holes would tend to appear in this particular casting and the amount of head provided in the guiding column to prevent the formation of such shrinkage holes is indicated by the upper portion of the poured material 7 shown in such column. FIG. 10 shows the casting freed from the sand and the column and casting cut along the lines 28 and 29, the inside of the remaining portion of the column being still filled with the cooled poured material 7 FIG. 11 shows the casting with the cooled poured material removed from the column and the inner wall of the latter bored.

FIGS 6 to 8 illustrate an example of making a draw bar 30 composed of an aluminous material melting at a temperature above 20% C. for use in the drawing chamber of a sheet glass furnace. The draw bar 30 may be about 50 x 350 x 30 cm. in size and is made in a two piece sand mold 31 provided with a sand core 32 for forming the slit 33 in the draw bar. The feed column is made of the same material as the draw bar, i.e., high melting aluminous material, and is composed of an upper fiared pouring end portion 34, an inlet branch 35 and two outlet branches 36, 36. At the juncture of the outlet branches 36, 36' with the inlet branch 35, the feed column is provided with lateral orifices 37 to take care of the shrinkage holes which would otherwise occur at such place in the cast product. During the pouring operation, when the level of the molten material being poured has reached the region of the orifices 37, the height of the charge in the inlet branch 35 is brought up to about 75 cm. above this level so as to cause the molten material to be injected with more force through the lateral orifices 37 and at the contemplated shrinkage hole location. As a result of this arrangement it is ossible to cast the draw bar in vertical position without any loss of material since the shrinkage holes is not present. As the feed column, like the draw bar, is made of electromelted material, only its upper part emerging from the mold above the line designated 38 need be cut ofi after cooling of the casting.

While we have hereinabove described and illustrated in the drawings, preferred embodiments of our invention, it will be apparent to those skilled in the art that modifications may be made thereof without departing from the scope of the appended claims.

We claim:

1. The method of casting refractory materials which are fusible at high temperatures to form articles of large size having openings extending through the bodies thereof, comprising pouring the refractory material in molten liquid form from a pouring device at a place spaced from the exterior of the mold into a guiding column independent of the mold, and constituted of a refractory material compatible with the refractory material being cast so as to be unitable therewith and having a melting point above that of the molten material being cast and such that the column retains its configuration throughout the pouring operation to form the opening in the body of the article, and using such column to guide the poured material from such exterior place to at least one selected discharge level spaced from the interior Walls of the mold, and in guiding the material poured from such device into the mold braking the downward flow of such material to reduce the violence of the feed thereof so that such material will discharge into the mold at said selected discharge level Without splash and with a minimum of force toward any interior wall portion of the mold, cooling the poured molten material and the refractory material of the guiding column to unite said guiding column with the casting formed by the poured molten material, exerting force on the solidified poured material in the interior of the column to remove the same therefrom, and cutting away 7 portions of the column to convert it into a liner for such opening in the article.

2. The method of casting refractory materials which are fusible at high temperatures to form articles of large size, comprising pouring the refractory material in molten liquid form from a pouring device at a place spaced from the exterior of the mold into a guiding column independent of the mold and constituted of a refractory material compatible with the refractory material being cast so as to be unitable therewith, pouring such molten material at high temperature into the guiding column to form the casting and to unite the material of the column with the poured material forming the completed casting, and during such pouring operation using such column to guide the poured material from such exterior place and initially discharge it into the mold through a lower discharge port spaced upwardly from the bottom interior wall of the mold, and then discharge such molten material into the mold through a lateral opening at a point spaced above said lower discharge port, the lower discharge port and lateral opening being at selected discharge levels and spaced from the interior walls of the mold, and in guiding the material poured from said device into the mold braking the downward flow of such material to reduce the violence of the feed thereof so that such material will discharge into the mold at such lower discharge port without splash and with a minimum of force toward any interior wall portion of the mold, and when the poured material is discharging through such lateral opening, building up the level of such molten material in the column to a point substantially above the level of the discharged molten material in the mold, and cooling the poured molten material and the refractory material of the guiding column.

3. The method defined in claim 2, in which the lateral opening is located in the region of the casting where a shrinkage hole would tend to form therein and is made large enough to enable a substantial fiow therethrough, and building up the level of the molten material in such column that it is discharged through such lateral opening with sufficient force to eliminate the formation of a shrinkage hole in said region.

4. The method of casting refractory materials which are fusible at high temperatures to form articles of large size, comprising pouring the refractory material in molten liquid form from a pouring device at a place spaced from the exterior of the mold into a guiding column independent of the mold and constituted of a refractory material compatible with the refractory material being cast so as to be unitable therewith within the body of the casting, pouring such molten material at high temperature into the guiding column to form the casting and to unite the material of the column with the poured material forming the completed casting, and during such pouring operation using such column to guide the poured material from such exterior place into a portion of the mold cavity to be within the body of the casting, feeding the molten refractory material into the column so that it is initially discharged into such mold cavity through a lower discharge port spaced upwardly from the bottom of such mold cavity at almost the same rate as the rate of feed thereof so that during such initial discharge there is substantially no head of molten material in the column, then when the molten material in the mold cavity rises to the level of the lower discharge port, increasing the head in such column until such molten material discharges into such mold cavity through a lateral opening at a point spaced above said lower discharge port, the lower discharge port and lateral opening being at selected discharge levels and spaced from the walls forming such mold cavity, and when the poured material discharging through such lateral opening has risen in the mold cavity to the level of such lateral opening, building up the level of such molten material in the column to a point substantially above the level of the discharged molten material in the mold for a given interval to discharge the molten material through such lateral opening at an increased pressure, cooling the poured molten material and the refractory material of the guiding column, and cutting away the portions of the column projecting beyond the solidified body of the casting.

5. The method defined in claim 4, in which the guiding column is used to discharge the poured material into the mold cavity at a plurality of progressively higher levels and at a rate almost the same as the rate of feed of such material through a plurality of lateral openings spaced above said lower discharge port at selected dis charge levels, at least one of said openings located in the region of the particular article being cast where a shrinkage hole would tend to form therein being larger in size than the other lateral openings to enable an increased fiow of the molten material into such region, and in which the level of the molten material in the column when the molten material discharges through said enlarged opening is built up to a point substantially above the level of such increased fiow through the enlarged lateral opening to increase the pressure of such increased fiow.

6. The method defined in claim 4, in which the guiding column selected is constituted of a refractory material having a melting point below the melting point of the molten refractory material being cast so that as such molten material is being guided therethrough, the material of the column will progressively melt and become united with the poured material of the casting, and such selected column having a wall which is substantially thicker in the portion thereof in which said lateral opening is located so that during the pouring operation the fusion of the column in such portion will be delayed.

7. The method defined in claim 4, in which the guiding column selected is constituted of a refractory material having a negative coefiicient of expansion and a melting point relative to that of the molten material being cast so that as such molten material is being guided therethrough, such column will contract and substantially retain its configuration, and during such cooling step will, at least in the portion thereof in which said lateral opening is located, expand so as to eliminate any shrinkage hole tending to form in the part of the cooling body of the casting through which such column portion extends.

References Cited UNITED STATES PATENTS 1,774,687 9/ 1930 Willard 22-203 3,177,281 4/ 1965 Umansky 264299 3,198,867 8/1965 Siggers 264299 1,042,734 10/1912 West 22-104 701,105 5/ 1902 Tolmic 22-104 1,589,730 6/ 1926 Williams 22-134 363,444 5/ 1887 Wilmington 22-201 273,658 3/1883 Wilmington 22-134 FOREIGN PATENTS 189,323 11/ 1922 Great Britain. 1,132,297 7/ 1962 Germany. 216,688 1/1961 Austria.

ROBERT F. WHITE, Primary Examiner.

R. B. MOFFITI, I. R. HALL, Assistant Examiners.

Claims (1)

1. THE METHOD OF CASTING REFRACTORY MATERIALS WHICH ARE FUSIBLE AT HIGH TEMPERATURES TO FORM ARTICLES OF LARGE SIZE HAVING OPENINGS EXTENDING THROUGH THE BODIES THEREOF, COMPRISING POURING THE REFRACTORY MATERIAL IN MOLTEN LIQUID FORM FROM A POURING DEVICE AT A PLACE SPACED FROM THE EXTERIOR OF THE MOLD INTO A GUIDING COLUMN INDEPENDENT OF THE MOLD, AND CONSTITUTED OF A REFRACTORY MATERIAL COMPATIBLE WITH THE REFRACTORY MATERIAL BEING CAST SO AS TO BE UNITABLE THEREWITH AND HAVING A MELTING POINT ABOVE THAT OF THE MOLTEN MATERIAL BEING CAST AND SUCH THAT THE COLUMN RETAINS ITS CONFIGURATION THROUGHOUT THE POURING OPERATION TO FORM THE OPENING IN THE BODY OF THE ARTICLE. AND USING SUCH COLUMN TO GUIDE THE POURED MATERIAL FROM SUCH EXTERIOR PLACE TO AT LEAST ONE SELECTED DISCHARGE LEVEL SPACED FROM THE INTERIOR WALLS OF THE MOLD, AND IN GUIDING THE MATERIAL POURED FROM SUCH DEVICE INTO THE MOLD BRAKING THE DOWNWARD FLOW OF SUCH MATERIAL TO REDUCE THE VIOLENCE OF THE FEED THEREOF SO THAT SUCH MATERIAL WILL DISCHARGE INTO THE MOLD AT SAID SELECTED DISCHARGE LEVEL WITHOUT SPLASH AND WITH A MINIMUM OF FORCE TOWARD ANY INTERIOR WALL PORTION OF THE MOLD, COOKING THE POURED MOLTEN MATERIAL AND THE REFRACTORY MATERIAL OF THE GUIDING COLUMN TO UNITE SAID GUIDING COLUMN WITH THE CASTING FORMED BY THE POURED MOLTEN MATERIAL, EXERTING FORCE ON THE SOLIDIFIED POURED MATERIAL IN THE INTERIOR OF THE COLPORTIONS OF THE COLUMN TO CONVERT IT INTO A LINER FOR SUCH OPENING IN THE ARTICLE.

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