US2811346A

US2811346A - Device for insufflating gas into a mass of molten metal

Info

Publication number: US2811346A
Application number: US267439A
Authority: US
Inventors: Spire Etienne
Original assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Current assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date: 1952-01-21
Filing date: 1952-01-21
Publication date: 1957-10-29
Anticipated expiration: 1974-10-29
Also published as: NL74999C

Description

Oct. 29, 1957 E. SEIRE DEVICE FOR INSUFFLATING GAS INTO A MASS MOLTEN METAL Filed Jan. 21, 1952 3 Sheets -Sheet 1 [12 m n 22 [Zznrze 5 Oct. 29, 1957 sPlRE 2,811,346

DEVICE FOR INSUFFLATING GAS INTO A MASS OF MOLTEN METAL Filed Jan. 21. 1952 3 Sheets-Sheet 2 jrzz-elz/ar Oct. 29, 1957 E. SPIRE 2,811,346

DEVICE FOR INSUFFLATING GAS INTO A MASS OF MOLTEN METAL Filed Jan. 21, 1952 3 Sheets -Sheet 3 DEVICE FOR INSUFFLATIN G GAS INTO A MASS OF MOLTEN METAL Etienne Spire, Montreal,

LAir Liquide, Societe lExploitation des France Quebec, Canada, assignor to Anonyme pour lEtudes et Procedes Georges Claude, Paris,

The present invention relates to devices for the insufilation of gas into a mass of molten metal in order to submit this metal to various treatments, and particularly to a device conceived mainly with a view to its application to casting ladles for molten metals which it allows to be transformed into treatment ladles, in a simple and economical manner, said device being also applicable, in a general way, to any enclosure capable of containing a mass of molten metal, in the refractory wall of which there is provided at least one plug, through which the gas for the treatment is forced, the gas permeability of said plug being obtained by making it out of a mass of porous refractory material.

For greater convenience in the description, the application of the invention will be considered for the case of casting ladles for metals, such as those used, for instance, in foundries, for carrw'ng the metal from the cupola or the smelting furnace to the molds or other points for pouring. In the devices designed heretofore for carrying out the technique described above, the gas permeable plug is located in a hole in the refractory lining of the ladle and passed through an aperture provided in bottom of the metal housing of said ladle and closed by a blower box provided with means for attachment on said metal bottom and with means for holding the plug through which the gas forced into the blower box enters the mass of molten metal contained in the ladle. Such an arrangement is complicated and expensive and requires a permanent transformation of the ladle which can no longer be utilized as a casting ladle.

A main object of the invention is to obviate these drawbacks, by rendering it possible to omit the blower box secured externally on the bottom of the casting ladle.

Another object of the invention is to provide a device for insufilating a gas into a mass of molten metal contained in a ladle, adaptable to the bottom of said ladle by requiring only the provision of a single narrow opening in said bottom. Such a device is applicable advantageously to small capacity ladles used in foundries for carrying the molten metal from the cupola or smelting furnace to the moulds, and the insuffiation treatment can be applied to the mass of metal during this transportation the duration of which is seldom lower than one minute and can reach five minutes.

The invention is characterized chiefly by the combination, in one assembly, of a tubular and preferably blind metal shell of a refractory plug, permeable to gases, which stops the aperture, and of a hollow element mounted on the shell and used both for introducing the treatment gas and for maintaining the plug and shell, this assembly being intended to be sealed in the refractory lining on the metal housing of the ladle, perforated for the passage of the hollow element.

In an embodiment the metal shell is in the shape of a truncated cone, the height of which is lower than the thickness of the refractory lining in which it is to be sealed, the gas permeable plug, of acorresponding shape, being the metal housing of Pic passed through the large end and forced through the narrow end aperture and the large end being then closed by the metal wall on which bears the hollow element for holding the plug.

The hollow element for holding the plug may consist of a screw, screwed in a central boss of the bottom of the shell, said boss fitting into a hole in the metal wall of the ladle for centering the assembly and the screw being locked on said bottom by an outer nut.

The hollow screw, provided with holes for letting out the gas at its portion inside the shell is connected through a flexible conduit with a gas bottle, under pressure, mounted on the suspension means of the on the metal housing of the latter.

The plug may also be maintained in the shell by a separate screw screwed in an aperture of the bottom of the shell and said bottom is-provided with a hollow externally threaded stud or bolt which is intended to be connected with a gas bottle and which may also be used for securing on the bottom of the ladle metallic housing, the assembly comprising the shell and the plug.

Various further and more specificobjects, features and advantages of the invention will appear from the detailed description given below taken in connection with the accompanying drawings which illustrate by way of examples preferred forms of the invention.

Figure 1 is a vertical section along the axis of a shell, plug and hollow screw assembly, showing this assembly in position on the bottom ,of a casting ladle;

Figure 2 is an elevation, with a partial vertical section, of a casting ladle transformed and equipped according to the invention;

' Figure 3 shows, partly in elevation and partly in. axial section, a shell, plug and hollow screw assembly, in -position on a casting ladle, for another embodiment Figures 4 and 5, are two views 1, for two further embodiments;

Figure 6 is a side elevation of with a gas insufllating equipment.

Referring to Figure 1, the refractory plug 1 consists in a block of a refractory porous material provided having the shape of a truncated cone and preferably on its lateral surface with ametal lining 2. According to the invention, a metal shell 3, is set up, formed by a lateral wall of rigid metal sheet of predetermined shape and dimensions, so that the plug 1 fits into said wall, issuing through the aperture or upper small end of the truncated cone. Before forcing the plug 1 into the shell 3, its lateral surface is coated. with a suitable refractory cement which insures a gastight sealing. When the plug similar to that of Figure a casting ladle provided 1 is in position in the shell 3, the total height of the assembly corresponds to the thickness of the refractory coating 4 placed on the metal bottom 5 of the casting ladle to be transformed into a treatment ladle by gas insufllation. The shell 3 is closed by a bottom which constitutes its larger end and which consists, for instance, of a disc 6 of metal sheet on the outer face of which is added, by welding, a central cylindrical boss'7, perforated, like the disc 6, and tapped for receiving a hollow threaded rod or screw 8 which, in the embodiment shown, constitutes the element holding the plug 1 in the shell 3. To this effect, the upper end .of said screw bears on a shoe 9, preferably provided with perforations distributed over its surface for the passage of the gas to be insufilated. The bottom 6 is secured on the shell 3 by welding, for instance, and the whole is placed on the inner face of the bottom 5 of the metal housing ofthe ladle perforated at 10 for the passage of the boss 7, and the whole is held by a nut 11 screwed on the screw 8 and bearing on the outer face of the bottom 5 through a washer 12. The refractory lining 4 of the-ladle is made in the usual man-- ladle or directly ner around the shell 3 and the upper portion of the plug 1, the upper surface of which, at the level of the surface of the lining, is in direct contact with the molten metal in the ladle.

It suffices to connect in a tight manner, by any suitable means, the outer end of the screw 8 with a conduit bringing in the treatment gas under a suitable pressure, this gas entering the cavity between the bottom 6 and the plug 1, through holes 13 provided in the thickness of the hollow screw 8.

The source of the gas to be insufliated may consist of a cylinder 14 (Figure 2), and supported in a suitable mounting designed for supporting it directly on the metal housing or on the suspension or carrying means of the ladle. The outlet of the cylinder 14 is connected by a flexible conduit 15 with the hollow screw 8 and, as already explained, the treatment by gas insufflation may be applied during the duration of transport of the ladle from the smelting furnace to the mould to be filled or any other receiving point for the treated molten metal.

In the embodiment shown in Figure 6, the equipment for insufilating a gas into the molten metal contained in a a casting ladle, is directly supported on the metallic housing of the ladle the hanging handle of which is shown in 17. The cylinder 14 which contains the gas to be insutflated is removably supported in a housing 19 made of metal sheets suitably secured to the metal housing of the ladle and coated, at least on its inner surface adjacent to the ladle, with a lining of a material such as asbestos for preventing the cylinder to be unduly heated. A pressure regulator 20 is connected to the outlet of the cylinder 14 and the low pressure outlet of said regulator is connected to an outflow meter 21 which is provided at its outlet with a hand valve or cock 23. A pipe 24 connects, by the intermediary of a flexible hose, the outlet of the cock 23 with a rigid pipe 22 intended to supply the gas to be insufllated to the insufllating device provided at the bottom of the ladle. The regulator 20 and cock 23 may be provided with any suitable devices allowing to control them from a place distant from the ladle.

In that embodiment, the ladle is intended to be used both for pouring molten metal by tilting it, the molten metal flowing over the pouring lips 25, and for pouring molten metal in a vertical stream from the ladle bottom through an orifice controlled in a well known manner by a stopper rod actuated from the upper portion of the ladle by the usual means not shown. The stream of molten metal from the bottom of the ladle flows vertically through a sleeve 26 into which gas may be blown from the pipe 22 through a control cock 27 in order to protect said stream against the influence of the surrounding atmosphere.

Referring now to Figure 3, the gas insufflating device shown in that figure differs from that shown in Figure l chiefly by the fact that the hollow screw which is supplied the insufllated gas, does not act to hold the porous plug in the metallic shell. In the embodiment of Figure 3, the thickness of the shell 53 is smaller at its upper portion than at its lower portion and the plug 1 is held in said shell by a threaded stud 8a which is screwed in a tapped hole of the bottom 56 welded at 611 to the lower edge of the shell 53, the upper end of said stud 8a bearing against a perforated plate or grid 9 applied against the lower face of the plug 1. A tubular threaded stud 28 is centrally secured to the bottom 56 and for instance welded at 29 on said bottom. The stud 28 is passed through an opening 10 of the bottom of the metallic housing of the ladle and the device as a whole is secured to the ladle by a nut 11 screwed on the stud 28 and bearing against a washer 12. The gas to be insutflated enters the tubular stud 28 through a connecting member 30 screwed into said stud, and flows into the shell through a plurality of holes 31 drilled in the bottom 56.

In the embodiment shown in Figure 4, the porous plug 1 is inverted, its smaller face being the lower face. A metal rod 32 having its upper portion split and spread out is embedded in the plug during the molding operation, and said rod extends outside the plug in order to provide a stud-bolt 32a. The shape of the shell 63 corresponds to that of the plug 1 and, as the shells of the embodi rnents already described, it is provided with a bottom 56 welded at 6a. The stud 32a is passed through a central opening of the bottom 56 and the plug is held in the shell 63 by tightening a nut 35 screwed in said stud. It appears that, with such an arrangement, a plug burnt or broken is readily removed and replaced by a new one.

The device as a whole is secured to the ladle as already explained in connection with Figure 3. A tubular threaded stud 28 is welded at 29 to the bottom 56 and passed through the opening 10 of the bottom 5 of the housing of the ladle, a nut 11 being then screwed on the bolt 28 and bearing against a washer 12. The stud 28 is connected to the pipe which supplies the gas to be insufllated, said gas entering the shell through holes 31 drilled in the bottom 56.

When the gas insufflating device is to be applied to ladles of large diameter and depth use may be made of the embodiment shown in Figure 5 and in which a circular opening 37 is cut in the bottom 5 of the metal housing of the ladle at a diameter sumcient to allow the shell 73 to be passed through said opening from the outside. The shell 73 is provided with a lower flange 3a to which the bottom 6 is welded at 6a and said flange is applied against the bottom 5 around the opening 37 by a numher, three for instance, of lugs 38 journalled upon studs 39 suitably secured to the bottom 5 and having a restricted outer portion threaded for receiving a locking nut 40.

The assembly: shell 73, plug 1 and screw 8 or stud 8a is of a simple and economical construction and may be supplied as such to foundrymen and metallurgists, who, to apply it to a casting ladle, only need to provide, in the metal wall of said ladle, in its bottom for instance, a hole with a diameter corresponding to that of the boss 7 or of the tubular stud 23 or of the lower end of the shell in Figure 5 or several holes, if several plugs are used. This hole or these holes can easily be stopped if the ladle is to be used for its initial purpose. For example, in the case of the smaller diameter hole, a threaded plug may be utilized, with the space in the refractory material filled in with suitable refractory material. In the case of a large opening a plate of suitable dimensions would be placed over the opening, either from the inside or the outside depending on the structure, and the space in the lining material within the ladle filled with suitable refractory material. In the case of an outside plate it is contemplated that this could be retained in position by lugs similar to those shown in Figure 5.

What I claim is:

A device for insufflating a gas into a mass of molten metal in a container by blowing said gas through a porous refractory plug, comprising a refractory lined metallic shell provided with a tapered opening in its bottom wall, a removable housing extending substantially into said tapered opening and extending below said opening to provide a skirt, a base plate releasably secured to said housing by clamp means fixedly attached to said shell, said clamp means contacting said plate and said skirt'to retain said housing in said tapered opening, a threaded hollow stud, a perforated shoe provided at the upper end of said stud on which said porous plug rests,

" said stud extending through the bottom of said plate,

a second hollow threaded stud positioned on the exterior of said plate and connected to said first mentioned 6 stud, said plug providing a gas chamber adjacent said 1,763,248 Moore June 10, 1930 plate, said plate having at least one hole adjacent said 1,836,196 Smelling Dec. 15, 1931 first and second mentioned studs for the passage of gas 2,265,511 Brassert Dec. 9, 1941 into said gas chamber, and means for connecting said second mentioned tubular stud with a source of gas to 5 FOREIGN PATENTS be insufilated through said stud. 456,234 i Man 29, 1950 498,983 Belglum Nov. 14, 1950 References Cited in the file of this patent 68 ,048 Great Britain Dec. 10, 1952 UNITED STATES PATENTS OTHER REFERENCES 728,261 Mark May 19, 1903 10 Metal Progress, June 1949, pages 817-820.