US2099208A

US2099208A - Apparatus for preventing the oxidation of metals

Info

Publication number: US2099208A
Application number: US66615A
Authority: US
Inventors: William H D Horsfall; Maunsell B Jackson
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-03-02
Filing date: 1936-03-02
Publication date: 1937-11-16
Anticipated expiration: 1954-11-16

Description

Nov. 16, 1937 w. H. D. HORSFALL ET AL APPARATUS FOR PREVENTING THE OXIDATION OF, METALS s Sheets-Sheet 1 Filed March 2, 1936 Nov. 16, 1937. w. H. D. HORSFALL ET AL 2,099,208 I .APPARATUS FOR PREVENTING THE OXIDATION OF METALS Filed March 2, 1936 3 Sheets-Sheet 2 UTI U 6111b TS T. wH.D.Horsfa11 Nov; 16, 1937. I w. H. D. HdRSFALL ETAL APPARATUS FOR PREVENTING THE OXIDATION OF METALS Filed March 2, 1936 3 Sheets-Sheet 3 $0 m ,TZ X w\ A HB wM/W IE I4.

Patented Nov. 16, 1937 un ts!) STATE APPARAT S FOR PREVENTING THE OXIDA- 'I'ION OF IVIETALS William H. D. Horsfall and Maunsell B. Jackson,

Toronto, Ontario, Canada I Application March 2, 1936, Serial No. 66,615

4 Claims. (01. 22-57) This invention relates to means for preventing the formation of oxides on the surface of castcooling periods in the process of making castings,

it has been the practice to allow themetal em- I ployed to be exposed to the atmosphere or other sources of oxidation. This resulted in the formation of oxides, commercially called scale, on the surface of the casting and the removal of this scale involved both cost of machining and loss of material.

In the casting of copper wire bars this lesson account of the scale was very considerable and it is to the making of these wire bars without scale that this invention more particularly relates. The'scaie on the=said bars is formed by the oxygen in the air combining'with the highly heated copper to form a thin coating of CuO.

The copper immediately below this oxidized coating combines with the CuO forming CuzO which results in the finished casting having a contaminated upper layer.

-The object of the present invention is to provide simple means for producing cast metal which will be in proper condition for use when removed from its mold, and for preventing the formation of oxides on the surface of molten metal.

We attain our object by providing means for expelling andexcluding air from the vicinity'of the hot. metal until such time as its temperature drops below the oxidation point.

Theconstructions are hereinafter more fully described and are illustrated in the accompanying drawings iii which Fig. 1 is aplan view of part of a casting machine showing our invention applied thereto;

, Fig. 23. section on the line 2-2 in Fig. 1;

Fig. 3 a section on the line 3-3 in Fig. 1; Fig, 4 a section on the line 44 in Fig. 1 showing the feed spout; pouring ladle and spouts;

Fig. 5 a section on the line .5-5 in Fig. 1;

Fig. 6 aside elevation of a modified form of machine, the hood and casing being shown in section;

Fig. 8 a plan view of another modified form of machine;

Fig. 9 a cross-sectional detail on the line 9- -9 in Fig. 8; i

'sides of the molds are concentric;

Fig. 11 a. cross-section on the line ll'll in ig.10:' Fig. 12 a cross-sectional detail of a mold and Fig. '7 a cross-section on the line Ir-1 in Fig. 6; i

Fig. 10 a plan view of part of. a modified form of the invention in which the inner and outer hood showing a rubbing strip carried by the latter; V

Fig. 13 a plan view of a modified form of mold in which the rubbing strip is-parried by curved fins or projections cast integral with the mold;

Fig. 14 a cross-section of the mold shown in Fig.13;

Fig. 15 a plan view of a modified arrangement of molds showing a hood and cover thereon; and Fig. 16 a cross-section on the line l6l6 in Fig. 15.

In the drawings like numerals of reference indicatecorresponding parts in the different figures.

Referring to Figs. 1 to 5, l is a Walker castingmachine which is well known in'the copper casting art and comprises a pluralityof molds 2 'tiltably supported on radial arms 3 carried by :a turntable 4.

I The latter is'suitably supported and rotated to move the molds past the filling point A'to a point (not shown) where the molds are turned upside down to dump the solidified metal therefrom. Thesurfaces of the molds which contact with the molten metal are thereafter'covered with bone ash and the molds are then turned right side up for receiving fresh -molten metal when they come round to the filling station A. I

Toexclude air from the castings in the molds until the temperature of the castings drops below the oxidation point, we provide a hood 5- extending transversely across but spaced from the tops of the molds. The hood has side flanges 6' which extend downwardly past the inner and outer sides of the molds so that the latter are free to travel through the hood which extends longitudinally from the filling point A to a point in the circumference of the machine where the castings have cooled to. a temperature below the oxidation point and are therefore immune to the chemical action of oxygen. Any suitable means v such as one or more-pipes 1 may be utilized to introduce a non-oxidizing gas, such as a reducing gas, an inert gas or steam, beneath the hood 5 whereby all air therein will be driven out and excluded therefrom.

' by providing strips I asbestos carried by -The quantity of gas used. may be minimized 8 of suitable-material such as either the molds 2 or the hood side flanges 6 for rubbing against the other of the said parts. In Figs; 1, 3 and 5, the molds are rectangular in plan and their sides are provided with longitudinal grooves 9 adapted to receive tangs Ill on side extensions ll having their faces adjacent the flanges 6 curved. The said faces are substantially concentric to the hood flanges 6 and carry the strips 8 for closing or substantially closing the space between the flanges 6 and extensions H. The opposite ends of each tang may be tapered to receive wedges l2 between said ends and the adjacent sides at the groove 9 whereby the extensions II are detach by. a corresponding number of spouts l5 on a. tiltable pouring ladle l6. The latter is fllled by a feed spout H which conveys the molten metal from a furnace l8.

Preferably the space above the molten metal" in the furnace I8 is filled with non-oxidizing gas and the feed spout I1 is enclosed by a casing l9 into'which the gas is also introduced. The casing I9 is also adapted to enclose the tiltable'pouring ladle I6 and its spouts IS. The casing communicates with the hood 5 so that air is excluded from the metal from the time it melts in the furnace until it cools in the molds to a temperature-below that of the oxidation point.

circular path, they may be pivotally carried on an endless chain 20which passes around sprockets, 2|, as shown in Fig. 6. The distance between the sprockets 2| and the speed of the chain are such that the molten metal poured into the-molds at one end A? of the machine will be solidified by the time it reaches the other end of the machine. The castings are discharged from the molds when the latter are turned upside down as they are carried around the sprocket 2| at the end-of the machine remote from the filling end. During the return movement of the molds alon the underside of the machine,the cavities of the molds will be covered with bone ash or other suitable material blown thereinto through one or more nozzles 22. Any suitable means such as the rails 20 may be provided to support the chain 20 intermediate the sprockets 2| and rails 20 are provided to support the molds while they are being returned in an upside down position. In this case the hood 5, which is similar to the hood 5 except for shape, extends from the filling point A .to a pointwhere the temperature of the castings has dropped below that at which oxidation would occur. In this case, the furnace Il may be located in alinement with the molds and'the casing l9 encloses ,the'feed spout I19, ladle I 8. and its, The ladles l6; I6 may be tilted, by any suitable means, to move the spouts l5, II into and out of their pouring positions. The casing I 9 comunicates with the hood 5' and nonoxidizing gas may be introduced thereintov by one or more pipes I. The strips 8, corresponding to the hereinbefore strips 8, may be carried by the molds or the hood side flanges B for contacting with the other of said flange and mold parts as the molds travel between the flanges.

In Figs. 8 and 9 is shown a modified form of copper molding machine in which the mold' is formed as a rotatable table 23 having a cavity 23 in itsupper surface. The molten metal is poured into the cavity by a spout li while the mold is rotated slowly and by the time the mold makes nearly one revolution the metal has cooled sufficientlyto permit its removal from the cavity. This molding machine is known in the art and the cast metal is removed in a continuous bar or strip which is subsequently cut into lengths for conveniently handling the cast copper. To prevent the copper from being oxidized, we apply a hood 5 over the mold 23, casing l9 over the spout l5 its ladle 16 and feed spout N and introduce a non-oxidizing gas beneath the hood 5 and easing m by any suitable means such as one or more pipes 1 3.

the casting at its point of removal from the cavity is below the oxidation point so that the casting will not be oxidized when it passes into the atmos phere. The flanges 6 of the hood 5 or the vertical sides of the'mold 23 may beprovided with a rubbing strip 8 for engaging the". other of said a mold and flange parts.

' A modified form of the machine shown in Fig. 1 is disclosed in Figs. 10 and 11 in which the molds 24 are segmental in shape with their inner and outer sides concentric to the hood flanges 6. The molds in this case are provided with lugs 25 which are hinged on pins 26 carried by bosses 21 on the arms 3 instead of by trunnions journalled in bearings carried by the arms 3 in Fig. 1. The extensions II? are curved throughout their length to lie against the sides of the molds 24 and to be concentr'c to the flanges 6 whereby the strips 8 will contact between the flanges. Any means such as a rail 28 or other suitable means may be provided to support the lower outer edges of the molds as they travel 'from a position ahead of the filling station to the point where they are turned upside down. When the end of the rail is reached, the molds will drop by gravity to the position indicated in dotted lines in Fig. 11 and'any suitable means such as a bent rail (not shown) may be employed to enclose the recesses .in the channels to embrace the stems of the T-shaped strips which project beyond'the plates for contact with the curved sides of molds which may be segmental as shown in Flgs, 10 and 11 or rectangular with curved rubbing extensions carried thereby. As the curved hoods 5 do not form complete circles, it is obvious that not only may the

flanges

6, or 6 be readily drawn into shape to fit the curved edges of the tops of the hoods 5 and be secured thereto by any suitable means such as by welding, but the plates 32 may also be readily bent to follow the curvature of the channels 3L,

In Figs. 13 and 14 is shown a rectangular mold the latter as the molds pass.

The rotary speed of the mold 23 is so regulated that the temperature of having curved integral side extensions II which may serve for engagement by strips 8 carried by the flanges 6 or for carrying the strips 8 so that they will engage the flanges 6.

the top of the hood 5 and is provided with deaooaaoel pendingflanges ill which are spaced from-the -so thatthega s or vapor may ilow lengthwise 01'.

-"side flanges I. The spaces between the flanges u and 6 at opposite sides of the cover communicate at their lower ends with the spaces between the flanges 6 and the sides of the molds. The

cover 33 is provided'with a suction outlet 35 whereby any gases introduced through the pipe I and escaping from the interior of the hood will be withdrawn through the outlet instead of escaping into the room in which the machine is set up g g V It .will be distinctly understood that the term non-oxidizing gas or gaseous means used throughout the specification and, claims is vintended to include any gas which will not liberate oxygen, any reducing gas with which oxygen will combine or any inert gas including superheated or dry steam. I

- What weclaim'as our invention is: 1. In apparatus at the class described the com-- bination of a tunnel-shaped hood formed with a top and opposed sides depending from the top;

the hood being openat the bottom throughout its length and at each end and formed as a continuous passage-way; a mold having its top,

above the level 01 the lower edges of the sides of the hood; means for moving the, mold lon itudinally into, through and out of the hood: and means for introducing at non-oxidizing gas 'or vapor into the hood above the level of the top of the moldso that the gas or vapor may flow lengthwise of the hood to the open ends to drive air iromthe hood and exclude it therefrom.

2. In apparatus 01. the class described the combination of a tunnel-shaped hood formed with a top and opposed sides depending from the top.

the hood being open at the 'bottom throughout its length and at each end and formed as a con-' tinuous passage-way: a mold having its top above the level oi the-lower edges of the sides ofthe hood; means for moving the mold longitudinally into, through and out of the hood: means for introducing a non-oxidizing gas or vapor into the hood above ,the level of the top 01' the mold the hood to the open ends to drive air from the hood and exclude it therefrom; mold pouring means at one end 01 the hood; and a closed casing connected-with the hood and enclosing said 5 mold-pouring means .but leaving sumcient opene ing for the entrance 0! the mold.

3. In W 01 the class described the combination oi t tunnel fehaped, hood formed with a sides of thehood having its top above the level of the lower edges of the sides of the hood; means for moving the mold lomtudinally into, through and out of the hood; means for intrdducing a non-omdimug gas or. vapor into the hood above the level of the top of the mold so that the gas or vapormav flow lengthwise oi the hood to the open 'ends to drive air from the hood and exclude it therefrom; and rubbing strips arranged lengthwise oi the molds and hood substantially closing the space at side between the mold and the hood and connected to the sides of one of said mold and hood parts. 4. In apparatus of the class described the combination oia tunnel-shaped hood formed with a top and opposed sides depending from the top, the hood being open at the bottom throughout its length and at each end and formed as a conwnmm n. D. nonsrann nauusunr. B. JACKSON.