US1150318A - Casting metals. - Google Patents

Description

S. P. WETHERILL, Jn.

l CASTING METALS.

APPLICATION FILED JAN. 27. 1908. nENEwED Nov. 29. 1910.

1,150,318. Panted Aug.I 17, 1915.

5 SHEETS-SHEET l.

INVENTOR;A

WITNESsl-is:

Y ATTORNEY. 'I

S. P. WETHERILL, In.

CASTING METALS.

APPLICATION FILED .IAN- 27| 1908- RENEWED NOV. 29, 19I0.

Patented Aug. 17, 1915.

5 SHEETS-SHEET 2.

A /l L L w I co i I Ill. i I l n mi@ 1T "Q y |I| il; l I() N r r l. I a) i EI WITNESSIS:

S. P. WETHEHILL, Jn.

CASTING METALS.l APPLlcATloN FILED JAN. 27. 1908. RENEwED Nov. 29. 1910. 1,150,318.

.Patented Aug. 17, 1915.

s SHEETS-SHEET 3.

s. P. wEIHERIL-L, In.

` CASTING METALS.

APPLICATION FILED IAII. 27, 190s. .IIEIIIzwED Nov. :29, I9Io.

1,150,31 Patented. Aug. 17, 1915.

5 SHEETS-SHEET 4- INVENTUR Ww. L

. ATTOR WITNESSES:

S. P-WETHERILL, In. CASTING METALS.

.APPLlc-Alon FILED 1AN.21,;1908. RENEwEn Nov. 29. 19m.

1,150,318.. Patented Aug. 17, 1915.

. 5 SHEETS-SHEET 5.

E@ VIATE@ FAT I ernten.

WETHERILL FINISHED CASTINGS COMPANY,

A CORPORATION. 0F PENNSYLVANIA.

0F PHILADELPHIA, PENNSYLVANIA,

CASTING METALS.

Specilication of Letters Patent.

Patented Ang. t7, 1915.

Application led January 27, 1908, Serial No. 412,782. Renewed November 29, 1910. Serial No. 594,769.

To all whomjtmay concern Be it known that I, SAMUEL PRICE WETH- ERILL, Jr., a. citizen of the United States, residingatPhiladelphia, in the county of Philadelphia and State have invented certain new and useful Improvements in Casting Metals; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. v

' My invention relates to certain new and useful improvements in metal casting furnaces and is particularly designed to provide a furnace applicable not only to the casting of metals of relatively low fusibility such, for instance, as tin, lead, zinc and their alloys, but particularly to the casting of metals of relatively high .melting points, such as aluminum, brass and the like.

In carrying out the invention, I provide an internally heated pressure chamber within which the metal to be cast is contained, which metal .is kept at the high temperature necessary forcasting, by means of the heat supplied to the interior of the chamber.A In some instances, the melting pot or container for the metal to be cast, constitutes the lining of the furnace chamber, and, in other instances, the melting pot or container is a separate crucible located freely within the interior of the chamber, in such manner as to be exposed both within and without to the pressure prevailing therein. By means of this latter expedient the pressure of the aeriform fluid upon the interior walls of the container or inner Crucible is counterbalanced by the pressure exerted upon its exterior Walls, thereby correspondingly relieving ,f

it of unequal strains.

The pressure supplied to the interior of the chamber is derived from any source of compressed air or similar aeriform fluid under pressure, the function of the compressed air or its equivalent being to exert a pressure Within the chamber sufiicient to force the metal from the melting pot or cru- -cible into the casting mold, through the intermediacy of a casting mold nozzle, communicatingwith the gate of the mold and extending below the surface of the molten metal.

of Pennsylvania,

An important feature of the invention consists l1n maintaining the casting mold nozzle in such relation to the heating chamber that, lduring the intervals between successive castings, it will be constantly sub- ]ected to the heating effects of the furnace, thereby maintaining it at such a high heat that there will be no opportunity for the metal to chill within-it when the casting mold is removed, and so that, after the removal of the casting mold, the metal in the said castingmold nozzle will drop freely back, regaining the level of the metal within the melting pot or crucible. To this end, in the preferred constructions, the casting mold nozzle is suspended from the roof or cover' VofA the heating furnace chamber and the products of combustion from the furnace pass out through exit passages surrounding the upper part of the depending nozzle.

A. further feature of the invention consists in-preventing the infiltration of the aeriform fluid into the nozzle, or past the nozzle into the gate of the mold during the casting operation, by interposing in the path of possible infiltration a. groove or chamber connected to a suitable vacuum, so that should the aeriform iiuid tend to gain access to the interior of the nozzle, or to the gate ofV the mold, it will be intercepted by the vacuum groove or chamber and will be diverted from entering the interior of the nozzle or mold.

Other features of the invention are also illustrated in the accompanying drawings, which show typical forms of apparatus embodying the improvements, and these details of construction and arrangement will be hereinafter more fully described.

In the drawings, Figure 1 represents, partly in section and partly in elevation, one form or modification of a metal casting furnace, assembled and arranged for carrying the invention into effect; Fig. 2 represents an exterior view of the lower portion of a mold appropriate for use therewith; Fig. 3 represents a partial top plan view of the cover of the furnace with the casting mold nozzle in place; Fig. 4 represents a central longitudinal sectionand partial elevation of another form or modification of the invention; Figs. 5 and 6 represent detail sectional views of certain parts thereof on a somewhat larger scale than Fig. 4; Iiig.` 7 'represents a` central section and partial elevation of another form or modiicaton of the invention; and Fig. 8 represents a horizontal section thereof on the plane indicated by the line 8-8 of Fig. 7. l Similar letters of reference indicate simi lar parts throughout the several views.

Referring first to the construction shown in Figs. l, 2 and 3, A indicates any suitable support for the main body portion of the. furnace, Which may conveniently consist of an outer shell B and cover C of metal, and an inner refractory lining a of fire-clay, or thelike. The furnace structure is strongly braced and luted, in such manner as to. Withstand the pressure exerted Within it by the compressed air er other aeriform fluid employed in the casting operation and also to lprevent important leakages of said yfiuid into the outer air or the.infiltration of air from without; its interior, therefore, constituting an air-tight pressure chamber during the casting operation.

In the furnace shown in Figs. 1, 2 and 3, referred to, the metal to be cast is intended to be contained Within a separate 4retainer or crucible b, which retainer preferably conslsts of an ordinary commercial cruclble of the usual graphite construction or of some other refractory material of a character which Willnot injuriously affect the particular metal to be cast. The retainer or crucible may be conveniently mounted upon suitable supports, as shown,'and may be heated in any suitable manner, as, for instance, by the circular burner D supplied With a miX- ture of gas andair fromthe blower-pipe E and gas-pipe F, as is usual in gas-heated crucible furnaces. The gas pipe F is provided with a cut-off d, the blower-pipe E is provided with a cut-ofi' cand a check valve f, and the mixer pipe G leading tothe burner is provided with a cut-olf g,' so that the quantity of air and gas appropriate to theparticular requirements of the burner Vmay be proportioned as desired, and so that the supply of fuel through the mixerpipe may be cut off during the casting operation. Compressed air or other aeriform fluid, under pressure, may be 'admitted tothe furnace chamber from a pipe H in any suitable man.- ner. At a suitable point in the pipe H mg bellocated a relief pipe I and the pipes and I may be provided, at their junction with a three-way cock lc, so arranged and disposed that by turning the handle of the cock, the pipe H may be put in communication with the interior of the furnace chamber to admit the pressure thereto, While, at the same time, the relief pipe I is cut off, or by other manipulations of the said handle the pipe H may be cut off and the relie pipe I put in communication with theinterior of the chamber, `or lastly, (as shown vvinterior of Ythe chamber.

-The casting nozzle employed in connection With the invention may be of varying l forms and constructions. In the form illus, -trated in Figs. l and 3', the nozzle is provided With a screw-threaded top portion Z having adepending tubular projection m,

and likewise having a series of openings or passages s, forthe exit of the products of combustion from the furnace, as will hereinafter more fully appear. The depending tubular projection m and the openings or passages s are lined Witha refractory coat-l ing n to protect them from the high temperatures to Which they are subjected, and this coating in most instances, will consist of a graphite composition of the usual kind employed for the makingof graphite crucibles. The nozzle, as thus constructed, may be screwed into a corresponding screwthreaded aperture of the coverV -C of the furnace, and, although removable for purposes -of'repair or substitution, is intended to remain permanently in place and depending from the cover, during the operation of the furnace, so that the products of combustion, when the burner is in operation, will pass out through the openings or passages s, thereby keepingthe nozzle at such a high setting of the metal therein;

T indicates one portion of any suitable- I two-part, or separable mold, and t indicates the gate of the mold. The interior of the mold, as for instance e', is connected by suitable channels as shown, With a Ipassage w leading to the vacuum pipe M, Whose function is to Withdrawl the air from thenold prior to each casting operation. Any suitable 4means for connecting the interior vof the mold with the vacuum pipe during the casting operation may be employed; for instance, a suitable cross-head N may be used, running in -suitable guides in the guide frame P and capable of being raised by l meansof a screw-threaded pipe section R connecting with the vacuum pipeM and forming a continuation thereof, and by means of the operating lever S, or by any mechanical equivalent for the said screvv threaded pipe and lever- The mold T makes a tight joint With the i cover, and, 'in order to make the-joint the more effective, I provide the mold With an operating handle .fr and screw-threadl the mold at y, as shown in Fig. 2, so as to fit a corresponding screw-threaded recess in the cover C. I furthermore provide it With a depending tubular projection .e and With a conical portion c immediately above said tubular projection, which conical portion is provided With an annular groove p (see Fig. 2). The groove p communicates with the rase,

vacuum channel w by means of a continua tion w of that channel, as illustrated in Fig. 1, so that during the casting operation the groove will likewise be under vacuum. rlhe purpose of this vacuum groove p is to intercept any possible inltration of compressed air that might otherwise tendl to force its way from the interior of the furnace, during the casting operation, into the interior of the nozzle, and which, if not thus interrupted, would enter the metal as it rises in the mold and cause blow-holes therein. The operation of this form of furnace and its accessories will be apparent from the foregoing description; when the casting mold is not in place, the burner D will be in operation and will heat the metal in the re-v tainer or crucible and the products of combustion will pass out through the apertures or passages c, thereby keeping the nozzle at a high heat. l/Vhen it is desired to cast, the cut-og g will be closed, thereby shutting olf the supply of fuel'to the burner, and, the three-way cock 7c will be so manipulated as .to close the relief pipe l and to open the pressure pipe H, thereby putting the pressure pipe H into communication with the interior of the furnace chamber. immedisecured air-tight in position, and the vacuum lpipe M thereupon withdraws the air from the mold and puts the groovepunder vacuum. rllhe compressed air or its equivalent enters the furnace chamber and exerting its force upon the top of the molten metal in the retainer or crucible forces the metal into the mold and makes the desired casting. As soon` as the casting is made, the three- Way cock 7c is manipulated in such manner as to shut olf the supply of compressed air through the pipe H, and to put the interior of the furnace chamber into communication with the relief pipe I leading to the open air, whereupon the mold is quickly removed and disassembled, so as to release the casting and prevent it from chilling.

lIn the form of furnace shown in Figs. 4, 5 and G, the same general arrangement of pressure chamber, interior Crucible, casting mold nozzle and the like, is presented as in Figs. l, 2 and 3. 1n this case, however, the crucible b may be raised, should occasion s0 require, by means of the vertically adjustable block b3 resting in the cup bt whose stem b5 is adapted to be raised byl means of the foot lever V, suitably counterweighted at b, to partially relieve the operator of the weight of the Crucible and its contents.

- The crucible may be heated by any suitable numberof gas and air burners, as, for instance, by the side burners D', and the basal burner D2 supplied with the necessary combustible mixture through the pipes G', which may all proceed from the same source. The metallic shell B of the furnace chamber is,Y as before, lined with refractory material a, and may likewise be insulated against heat radiation by suitable exterior lagging, as shown.

rlhe furnace chamber cover C is cored out, so as to form passages s, round aboutthe upper end of the depending castingrnold nozzle m, and these passages coinmunicate by the outlet s2, with a device for imparting the heat of the outgoing products of combustion to the incoming air, and which will presently be described. lThe casting mold nozzle m is preferably of graphite crueible composition or of like refractory material. 1t is preferably of double conical configuration at its upper end, one of the conical surfaces fitting within the screw rin@ mi' and the other conical surface fitting within a corresponding conical recess of the cover C with intervening refractory packing m; so that, by screwing the ring mL into its socket, a tight oint will be insured for the nozzle at both of its said conical surfaces. u,

rlhc passage s2 communicates with the flattened interior of the metallic heat radiator `W contained in the chamber 1V and is surrounded with suitable refractory heat absorbing and retaining asbestos or the like The radiator WT leads to the exit pipe or flue Vim which conducts the products of combustion to the outer air, when the spring seated valve e is open. The incoming coinpressed air, entering through the air intake z2, passes through the perforated header e, refractory material fc', header et, and passages 82 and s', into the interior of the furnace chamber when the air-intake valve .e5 in the pressure pipe is opened. The si1nultaneous opening and closing of the valves e and .e5 may be effected by any suitable mechanism, as, for instance, the operating handle, counterweight, rotary cam, and moderating dash-pot shown in Fig. 4. The 'mode of operation of the furnace shown in Figs. Ll, 5 and 6 will be understood from the description of the operation of the furnace shown in Figs. 1, 2 and 3. When the gas burners are ignited, the pressure valve 25 is closed and the gas outlet valve e -is opened; so that the products of combustion, on their way out, keep the nozzle hot and store their heat in the refractory filling of the chamber `W. l/Vhen Fthe mold is in place, with its gate in alinement with the hollow interior of the nozzle the pressure valve .e5 is opened, the gas outlet valve e is closed, and the several gas-burners are cut olf; thereby permitting the pressure to enter the chamber and effect the casting.

1n the form of furnace illustrated in Figs. 7 and 8, instead of employing a melting pot or crucible exposed both interiorly and exterierly to the pressure of the aeriform fluid, 1 employ as such melting pot or crucible the ilo refractorylining a2 of the furnace chamber B2. In this modification of the invention, moreover, the mixture of air and gas, admitted through the ai'r tube F and gas tube G', is supplied preferably to downwardly directed twyers a3, a4, and in such manner tering the passage s4 pass out into the gas exit pipe H. The casting mold nozzle fm?, of graphite composition, or like refractory material, has a main body portion of general conical outlines or configuration which fits within a correspondingconical aperture of the cover C? knf thefurnace. AIt is likewise conical on itsupper surface m3, and is bolted down into tight union with its metallic socket, by means of the cap r having -a screw-threaded tubular` projection r2, upon which is designed to be screwed the mold, as indicated in Fig. 7 by the letter T', so that the gate of the mold is in alinement with the conical interior of the casting mold nozzle. The gas outlet pipe H is provided with a cut-off valve L, the gas inlet pipe G is provided with a cut-off valve g', the air inlet pipe F is provided with a cut-off valve f and the pressure inlet pipe L is provided with a cutofil valve Z, and thesey several valves or cut-offs are connected by the system of operating levers shown, in suchmanner that by throwing the counter-weighted lever vf to one limit of its movement, the air and gas pipes of the gas burners and the gas outlet pipe will be opened and the pressure pipe closed; whereas, Vwhen thrown to the opposite limit of its movement, the pressure pipe will be opened and the other pipes closed. By means of the.slots shown in the vertical member @2 of this system of levers,

the valve z/ will close after the .valves g and f', the valve g closing first. In the adjust,

ment indicated in Fig. 7, the pressure pipe afalve Z is assumed to be closed, and in order r to open it and close the other. valves, f', g-

the molten metal is maintained by means of the burner flames, whose products of combustion, in leaving the` furnace chamber, keep the casting mold nozzle at such a high temperature that it is impossible for any of the casting metal to chill in said nozzle when the casting mold isfremoved. -In this respect, the construction shown in Figs. 7

and 8 shares the advantage of the like constructions shown in the other figures, and, at the same time, the furnace of.F1 gs. and 8 effects its casting operations and its intermanner as vthat of the said furnaces.

Having thus described my invention, what I claim is l. A pneumatic casting apparatus, comprising a chamber within which the molten mediate `heatings in substantially the same prising a chamber within which the molten metal to be cast is contained, a fuel-burner opening into said chamber for heating the same by internal combustion, a casting-mold nozzle communicating with the molten metal, a conduit for supplying compressed airto the chamber during the casting operations, and means for opening the chamber for the escape of the products of combustion during the interval between the casting operations and for closing it during the casting operations, the said casting-mold nozzle being in the path ofthe outgoing products of combustion; substantially as described;

3. A pneumatic casting apparatus, comprising a pressure chamber'for containing ,Y

\ the casting-metal, means for internally heating said chamber, a casting-mold lnozzle -dipping from above into the casting-metal,

and means for producing within said chamber, a super-atmospheric pressure; substantially as described. Y

4. A pneumatic casting apparatus, comprising an internally-heated pressure chamber, a casting-metal container located therein and exposed interiorly to the pressurel pre-l vailing in the chamber, means for taking up and counter-balancing the tendency of said interior pressure to rupture the walls of the casting-metal container, and a casting mold -nozzle dipping from aboveinto the castingmetal`; substantially as described.

5. A pneumatic casting apparatus, provided with an air-pressure chamber within which the metal to be cast is contained, a I

` casting mold and a casting-mold nozzle, and

means for intercepting the infiltration of the compressed air from the pressure chamber into the mold; substantially as described.

6. A pneumatic casting apparatus, provided with an air-pressure chamber within which the metal to be cast is contained, a

casting-mold and a casting-mold nozzle, and means for intercepting the infiltration of the compressed'air from the pressure chamber into the mold, said means consisting of an exhaust connection interposed `in the, path of possible infiltration; substantially as described.

7. A pneumatic casting apparatus, pro-I vided With a combined furnace and pressure chamber, a casting mold, and a depending casting-mold nozzle having at its point of suspension outlying passages for the passage ofthe products of combustion fromrthe chamber; substantially as described.

8. A pneumatic casting apparatus, comprising an internally heated pressure chamber, Within which the molten metal to be cast is contained, a casting mold communieating with thev molten meta-l therein, and valve mechanism for simultanenously opening the pressure admission and closing the relief. exhaust of said chamber; substantially as described.

In testimony whereof I ax my signature,

in presence of two Witnesses.

SAMUEL PRICE WETHERILL, JB. Witnesses: v

' F. J: KING, A

T. HoPrLE.

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