US2568525A

US2568525A - Gas hood for casting machines

Info

Publication number: US2568525A
Application number: US52572A
Authority: US
Inventors: Waddington Ralph Henry; Welblund Albert George
Original assignee: International Nickel Co Inc
Current assignee: Huntington Alloys Corp
Priority date: 1948-06-05
Filing date: 1948-10-02
Publication date: 1951-09-18
Anticipated expiration: 1968-09-18

Description

Sepf- 18, 1951 R. H. wADDlNToN Erm. 2,568,525

GAS HOOD FOR CASTING MACHINES R. H. wADDlNGToN x-:TAL 2,568,525

GAS Hoon Fox CASTING MACHINES Sept. 18, 1951 3 Sheets-Sheet 2 Filed Oct. 2, 1948 d 0 vr www M ma.: on www# m V r mw n. y@ m Q y Aw www@ R. H. wADDlNG-roN ErAL 2,568,525

sept. 1s, 1951y GAS HOOD FOR CASTING MACHINES 3 Sheets-Sheet 5 Filed Oct. 2, 1948 Patented Sept. 18, 1951 GAS HOOD FOR CASTING MACHINES Ralph Henry Waddington and Albert George Welblund, Sudbury, Ontario, Canada, assignors to The International Nickel Company, Inc.,

New York, N. Y.,

a corporation of Delaware Application October 2, 1948, Serial No. 52,57v2 In Canada June 5, 1948 2 claims. (01.22479) The present invention relates to an improved machine for continuously and proteetively molding metals and alloys in which molten metal is poured into the top of a mold from a tiltable ladle and the hot ingot formed is continuously withdrawn from the bottom of the mold cavity.

It is well recognized, in the founding art that metals in the molten state are particularly susceptible to contamination by some of the gases with which they may come in contact, such contamination resulting in either undesirable surfaces on the iinished casting or in the occlusion of undesirable gases withinthe casting itself. It has already been proposed in the prior art to enclose the ladle within a hood-like covering. These prior art arrangements, however, were cumbersome and expensive, and time-consuming removal of the hood was required when replacement or adjustment of the ladle became necessary.

AWe have invented an improved machine in which pouring of molten metal from the furnace to the ladle and subsequent pouring from the ladle to the mold is carried out within an improved hooded enclosure. This hooded enclosure is provided with means for making vertical, longitudinal and transverse adjustment of the ladle from controls outside the hood and is also provided with means for rapid and easy removal of a section of the hood to permit easy exchange of ladles. During operation, the hooded enclosure is preferably lled and supplied with a gas under slight pressure. The gas used for filling the hooded enclosure is substantially inactive toward and is not absorbed to any substantial extent in the molten metal being poured.

An object of the present invention is to provide an improved method and machine for continuously casting molten metal in which the molten metal during pouring is maintained in contact with non-oxidizing and/or reducing gases during the pouring and casting operation.

`A further object of the present invention is to provide an improved machine for continuously casting molten metal with means for adjusting the ladle in relation to the furnace pouring spout and the casting mold filling port by control means which are located outside a protective hood.

The foregoing and other'objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, in Which- Fig. 1 illustrates a longitudinal, sectional view, taken on a central vertical plane and `partly in elevation of a vibrating, vertically split, sectional 2 mold casting apparatus embodying the present invention;

Fig. 2 is a similar vertical sectional view depicting the hooded enclosure and the upper part of Fig. 1 on an enlarged scale with the casting mold and other details omitted for the purpose of clarity:

Fig. 3 shows a vertical cross-sectional View taken axially of the ingot mold; and

Fig. 4 depicts a plan view with the upper parts of the hood and the furnace spout omitted.

Fig. 5 is a detailed view of a portion of Fig. 2 illustrating the manner of interposing gaskets between the securing members of the respective hood sections.

Generally speaking, the new improvement for a machine for continuously casting molten metal embodying the present invention comprises a sectional hood, the mold end section of which is easily removable, assembled around and. enclosing all parts of the machine in which the molten metal would normally be exposed to the atmosphere. By the use of the novel combination embodying the present invention, the furnace pouring spout, the ladle, the ladle outlet and the filling port of a vibrating, vertically split, sectional mold are all enclosed within ;a sectional hood. Means are provided for circulating within the hood a gas which is non-reactive with and substantially insoluble in the molten metal. The molten metal emerging from the furnace pouring spout and passing through the ladle and ladle outlet to the filling port of the vibrating, vertically split, sectional mold is thus protected from contamination by oxidizing or occluded gases while in the molten state. Control means located outside the hood are also provided by means of which vertical, longitudinal and transverse adjustment of the ladlewithin the hood ,may be made.

Referring more particularly to Fig. '1, the hood assembly is generally designated by the reference character A and is disposed over anopen-ended, vibrating, vertically-split mold I, having a water jacket 2 and driven rolls 3 for withdrawing a finished casting 4. As may be seen more clearly from Figs. 2 and 3, the hood consists of a bottom or pan section l5 and a sectional cover member consisting of a rear seetion 6, an intermediate section 'l and a front section 8. These cover sections are joined together in gas-tight arrangement and are assembled with the pan section 5 in gas-tight assembly as hereinafter described. The bottom or pan section 5 is provided with a raised bearing `base 9 at each Arotation of both of the rods I5.

. side of the furnace outlet on the pan bottom and with a continuous gas duct I along two sides of the pan member and across the ladle outlet end of the pan.

The gas duct I0 is an open-bottom duct of sheet metal or other suitable material and is provided with a gas inlet pipe II. Slots or holes in the sides of the gas duct I0 and a plurality of apertures I0-a in the top surface thereof perl. mit escape of the gas into the hood assembly A,

whence it is withdrawn through gas outlet I2 in the top of the hood assembly. The pan section is provided with a bottom opening I3 dis. posed centrally above the open end of the openend mold I.

A channel member I4 forms an extension of the outer Walls of the bottom pan section 5 at its forward end and along two sides;thereof. In use, this channel member is filled with powdered asbestos or other packing material to form stuffing box I1 and a steel bearing support I 3. the stuillng box providing a gas-tight seal. The upper end 26 of the ladle tilting arm 24 is preferably in the form of a circular rod extending at the surface of the molten metal. It will be noted a gas tight seal with the hood as hereinafter described.

A pair of rods or shafts I5 pass longitudinally through the pan bottom section 5 on cach side of the ladle I6 as may be more clearly seen 1n Fig. 4. At the forward end of the pan bottom theserods pass through and are supported by a stufng box I1 and at the opposite or furnace outlet end of the pan these rods are supported 1n a piece of bearing steel I8 carried on the inner side of the end wall of the pan 5. The furnace outlet end of each of these rods is threaded and carries thereon a threaded sliding bearing block I9 having a notch 20 therein. The bearing block I9 is also slidably supported on the raised bearing base 9 and is adapted to move therealong on rotation of the longitudinal adjusting rods I5. A bar 2I is carried in notches 20 andis secured between the sliding bearing blocks I9 to the rear end of ladle I6 by welding or other convenient means', thus providing for longitudinal adjustment of the ladle. The bar 2| and the notch are so arranged that the bar ts loosely in the notch. By this arrangement, the outlet 23 of the ladle I6 may also be moved from side to side within the hood by rotating only one of the adjusting bolts I5, thus providing transverse adjustment and it will be apparent that longitudinal adjustment of the ladle may be `made by Rotation of these rods from outside the hood is made by rotation of the hand wheels 5I thereon.

The ladle I6 is provided with a lining 22 which is preferably of fire clay brick cemented in but may be of any other suitable refractory material which is adapted to. withstand the temperature of the molten metal and which is inactive thereto. The forward end of the ladle I6 is provided with an outlet 23 which is preferably lined with a Zircon or equivalent bushing. This ladle outlet is preferably disposed centrally above the opening of the open-end mold I and it will be clear from the drawing that this preferred disposition of the ladle outlet may readily be obtained by use of the longitudinal adjusting rods I5. The ladle is supported intermediate the two ends by a ladle tilting member 24 which, as shown, is preferably in the form of an arcuate arm which is keyed at its lower end to a rotatable shaft 25. Suitable mechanism for rotating the shaft, such as a worm and gear (not shown), may be provided. The worm and gear or other shaft rotating mechanism is disposed outside of the pan wall and outside of the channel member I4. The shaft 25 is journalled within a that there is a rise in level of the bottom of the ladle immediately beyond the skimming baffle 21 and that this change in level occurs approximately beneath the skimming baille. With this arrangement it is possible to keep a larger pool of molten metal in the ladle and it is also possible to drain the molten metal back to the ladle by tilting the outlet end of the ladle upward thereby preventing spillage from the outlet end.

As stated hereinbefore, a sectional cover section designated by the

reference characters

6, 1 and 6 is provided and is so arranged as to provide a gas-tight seal with the pan section. Angle pieces 28 are provided along the adjacent edges of cover sections 6 and I and these are bolted together with bolts 29, a gasket of asbestos sheet or other suitable material 29 being compressed between the outwardly extending legs of the angle pieces. Similar angles 28 are provided along the lower rear edge of cover section 6 and along the rear and upper edge of pan 5 and these are similarly bolted together by bolts 29 and a suitable gasket material therebetween to provide a gas-tight seal.

As referred to, means are provided in the improvement embodying the present invention whereby pouring from the furnace to the ladle is carried out within an enclosure substantially de-v void of contaminating gases. For this purpose an opening 30 is provided in the rear wall of cover section 6 through which the collar 3| and the furnace pouring spout 32 pass. A gas-tight seal between the rear wall of the coversection 6 and the collar is provided by any convenient means such as an annular seal ring 33 and a ring packing 34.

Front cover section 8 is joined in gas-tight engagement with intermediate cover section 1 in a manner somewhat similar to that by which intermediate section I and rear section 6 are so joined. Angle pieces similar to those used for joining sections 6 and 1 are secured to the adjacent side edges of cover sections 1 and 8. An angular upwardly extending flange 36 is provided across the top of cover section 8 and a downwardly inclined wall 31 is provided acrossfthe forward side of cover section 1, these

portions

36 and 31 being adapted to retain a gasket v(not shown) interfacially therebetween in the manner shown in Fig. 5 as will be described hereinafter. Inclined wall 31 is provided, as shown, with two or more brackets 38. In cooperative relation to the ,brackets 36 there are provided two or more brackets 39, at right angles to the brackets 38 and in longitudinal alignment therewith, and mounted on the top of cover section 8. Eye bolts 40 are engaged in each of brackets 38 and a threaded portion 4I passes through slots in the brackets 39. By the use of wing nut 42 the cover sections 1 and 8 may be pulled together. Identical eye bolts 40 are provided on the sides of the cover assembly 'I and 8 and it will be seen that a gas-tight joint is obtained when a gasket of sheet asbestos or other suitable packing material is placed between the

parts

36, 31 and between the angle pieces, and when the wing nuts 42 are tightened suiliciently to compress the gasket. This method of assembly of the forward sections l and 8 allows the front part of the hood, i. e., section 8 to be removed quickly and permits replacement of ladies duringoperation.

Elements 5I) (see Fig. 4) are provided to facilitate handling of the hot ladle. As will be seen in the drawing, the elements 50 are in the form of rods and are welded or otherwise secured to the ladle. The ladle I6 is always preheated before being placed under the hood to prevent congealing of the molten metal when the operation is started. If the operation must be stopped temporarily because of a breakdown, the ease of removal of section 8 permits the insertion of a bolt in the still liquid copper or metal in the mold, which bolt serves as a contacting link when operation is resumed, in effect thus serving as a new dummy bar such as is commonly used at the start of the operation.

With the cover sections B, 1 and 8 assembled in accordance with the foregoing description, the lower edges of these cover sections are pressed into the powdered asbestos or other packing material contained in the channel member I4, thus completing the gas-tight seal. Means are provided for retaining the cover section in this position, this means consisting of eye bolts 43, attached to suitable brackets on the pan section 5 and having a wing nut engaging a vertical bracket on the hood section 8. Flanged

sight glass holders

44 and 45 are provided on one side and the end, respectively, of cover section 8 and these holders are each fitted with a sight glass (not shown) through which the operator may observe the adjustment of the ladle outlet 23 over the open-end mold I. Cover section 1 may likewise have a glass holder 44 to observe the metal streams flowing from the furnace to the ladle. The cover section 8 is also provided with

flanged extensions

46 and 41 which are tted, respectively, with a clean-out plug in axial alignment with the ladle outlet 23 and a gas pressure test pipe. A gas ring 48 is positioned in the pan outlet I3 between the ladle opening 23 and the opening in the mold I and a ring gas inlet 49 is provided through which gas is introduced to the ring. The gas so introduced may be a gaseous hydrocarbon which is decomposed to produce finely divided free carbon which is deposited on the meniscus of th molten metal in the mold.

In the operation of the improved machine for continuously casting molten metals, gas inlet II is opened, allowing gas to ilow into the gas-tight hood. The gas used is preferably charcoal producer gas but may be any suitable gas which is substantially non-reactive with the molten metal and substantially insoluble therein and which. furthermore, satises the conditions herein set forth. At the same time that gas inlet II is opened, a valve or other controlling means in gas outlet I2 is opened, thus permitting air or other undesirable gas within the hood to be 4displaced before molten metal is introduced into the ladle I6. Observations are made through the sight glasses and any adjustments of the ladle outlet `flow into the ladle I6 and at the same time gas inlet 49 is opened. While it is preferred to use the apparatus embodying the present invention in association with a vibrating sectional mold,

whose sections are vibrated transversely to the direction of movement of the congealing metal within the mold, it will be apparent to those skilled in the art that the improvements of the present invention can be readily adapted to other types of continuous or discontinuous casting apparatus.

Although the present invention has been described in conjunction with specific preferred embodiments thereof, it will be apparent that modifications and variations may be made, such as other means for tilting the ladle, without departing from the spirit and scope of the present invention as defined in the following claims.

We claim:

1. In a machine for continuously casting metal shapes having a furnace spout, a ladle removably supported adjacent said spout and positioned to receive molten metal therefrom and having an outlet end portion provided with an outlet opening from said ladle and a mold beneath the ladle outlet opening adapted to receive the effluent molten metal from the ladle outlet opening, the combination therewith of a sectional hood consisting of a base section coextensive with the assembly and formed with a, marginal sealing channel and an opening underlying the ladle outlet opening and side and top wall sections consisting of a furnace spout section having gas sealed connection with the spout, a removable section enclosing the ladle outlet end portion and an intermediate section, said sections being united to provide a gas-tight unitary structure with the base section for enclosing said spout, said ladle and said outlet, said hood being provided with means for circulating inert gas therethrough including a perforated gas duct mounted on the base marginal portion to be coextensive with the side walls of the removable section, said base section being provided with adjustable supporting means for the ladle and having operating connections thereto extending externally of the hood, said removable section having its top wall in a plane lower than the top wall of the furnace spout and intermediate sections and being formed with a clean-out opening vertically aligned with the ladle outlet opening, a removable plug for the clean-out opening and readily detachable securing means for the removable section consisting of threaded bolts carried by brackets in one member and engaging slotted brackets in an. adjacent member and having wing nuts threaded thereon to facilitate replacement of the ladle.

2. In a machine for continuously casting metal shapes having a furnace spout, a ladle removably supported adjacent said spout and adapted to receive molten metal therefrom and having an outlet end portion provided with an outlet opening from the ladle and a mold beneath said outlet opening adapted to receive the effluent molten metal from said outlet opening, the combination therewith of a protective gas hood comprising sectional hood members consisting of a base section coextensive with the assembly and formed with a marginal sealing channel and with an opening-underlying the ladle outlet opening, and side and top Wall sections consisting of a furnace spout section having gas sealed connection with the furnace spout, a removable section having its top wall overlying the ladle outlet portion and an intermediate section provided with a gas discharge port in its top wall, said removable section having its top wall in a plane lower than the top wall of the furnace spout and intermediate sections, said sections being united to provide a ,gas-tight unitary structure with the base section for enclosing said spout. said ladle and said ladle outlet opening, said hood being provided with means for circulating an inert gas therethrough, said circulating means consisting of a perforated gas duct formed in the base member for introducing the gas within the hood coextensive with and adjacent the side walls of the removable section and an outlet conduit connected to the discharge port of the intermediate section, said base section being provided-with adjustable supporting means for the ladle having operating connections thereto extended externally of the hood and readily detachable securing means for the removable hood section to facilitate replacement of the ladle.

RALPH HENRY WADDINGTON. ALBERT GEORGE WELBLUND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS