US2908490A - Fine wire drawing furnace - Google Patents

Description

Oct. 13, 1959 l w. sT. JOHN ErAL 2,908,490

FINE WIRE DRAWING FURNACE Filed Nov. 23, 1954 2 Sheets-Sheet 1 INVENTORS Wal. 57T ,qTa/ewf- 7T A. Hama/wv. BY

Oct. 13, 1959 Filed Nov. 23, 1954 W. ST.

FINE WIRE JOHN ETAL DRAWING FURNACE 2 Sheets-Sheet 2 FINE WIRE DRAWING FURNACE William St. John, Bloomfield, and Thomas A. Hoffmann, t Newark, NJ., assignors to Westinghouse Electric Corf .Y poration, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 23, 1954, Serial No. 470,636

3 Claims. (Cl. 263-3) The present invention relates to the manufacture of be easily removed from its operating position while still hot to thread a wire over the pulley at the entrance to the furnace tunnel and through the wire drawing die, a furnace elevating mechanism is provided that shifts the furnace backward and upward on two sets of pivots without jarring and thus damaging the furnace refrac-v tory. t v, The wire drawing furnace of the present invention uni-Y formly heats the wire. Minor gas pressure liuctuations do` not effect wire temperature. Drafts are eliminated.

' 'Ihe wire is protected until it enters the die. Water incandescent and uorescent lamps and, more particularl ly, to a ltungsten or molybdenum wire drawing machine. The present tungsten or molybdenum wire drawing machines reduce the size and weight of wire by passing the wire over a pulley, through a furnace to heat it, and then 'through a preheated die having a smaller diameter hole therein. The furnace employed may consist of a -ilat manifold having approximately 200 burner tips formed in said manifold and from which the gas is emitted Vand burned. The manifold is located underneath the wire and from time to time the burner tips become clogged with aquadag, the wire drawing 1ubricant, falling thereon. In addition, another of the defects of the prior art furnace is non-uniform heating of the wire as the wire passes over the individual burner tips and in and out of the soft flame envelope thereof. y Minor gas fluctuations and drafts aect the flame locations and tend to produce non-uniform heating of the wire from the time it enters the furnace until it leaves the die.

`Inthe past various types of U-shaped lgrids have been installed in the furnace around the wire to indirectly heat the wire. Water jackets on either side of the furnace` manifold have also been applied to protect or bae themanifold from drafts and to conduct heat away from the working parts of the Wire drawing machine.

Thesewater jackets require considerable maintenance due to leaks. In addition when water ow ceases, due to clogging of thevjacket, high pressure steam may develop within the jacket during operation'of the furnace.

If the wire undergoing drawing is not uniformly heated, excessive wear on `the die itself reduces the die life and produces varying wire weight or diameter from one end of a piece ofv wire to the other. Obviously poorer machine efficiency and low production results from wire breakage, respooling and die replacement.

jackets and grids are not necessary. The burner does not clog. In addition, die life a's increased, wire breakage and attendant respooling Iis reduced and lgas savings are effected. Quality in the form of a uniform weight of wire is improved and production in the form of total length of wire drawn is increased. In its general aspect the present invention has as its objective elimination of the defects of the prior art design of Wire drawing furnaces.

A specific object of the present invention is a wire: drawing furnace and in which the wire is completely' enclosed, indirectly heated thereby, and enveloped in va; protective atmosphere until the wire enters the die.

AnA additional object is a wire drawing furnace whichi I is easily removed from its operating position without;

jarring and damaging the burner refractory.

' Other objects of the present invention will become apparent to those skilled in the art to which it appertains; as the description thereof proceeds. Referring now to the drawings in which like numerals: of reference indicate similar parts through the severall views: Fig. 1 is a side elevational view of a wire drawing: machine incorporating the wire drawing furnace of the: invention and showing the nonoperatingvor wire loading; position of the wire drawing furnace in dotted lines.

Fig. 2 is a vertical end view of the drawing die heath and the exit end of the Wire drawing furnace along the: line Il-II of Fig. 1 in the direction of the arrows and.' showing the wire drawing furnace in its operating posii tion.

of Fig. l in the direction of the arrows, and showing the inoperative position of the furnace in dotted lines.

Other methods of heating the wire, such as surrounding t the wire with a tube and heating the tube from the side by burners was found unsatisfactory. Again, direct use of high frequency coils around the wire was found impractical and uneconomical.

Hence, it has been found advantageous according to the present invention to'provide a wire drawing furnace for a` wire Vdrawing ymachinerwhich will eliminate the above mentioned defects, increase production and improve quality of the drawn wire while at the same time reducing the cost of production.

The furnace consists I of a tunnel-like body open at the bottom and at the ends through which the wire passes. The tunnel walls are gas heated from a ribbon extending along the length thereof so that the flames therefrom' sweep down the furnace walls but do not impinge directly on the wire undergoing drawing. The furnace of the present invention permits the wire to be completely enclosed, indirectly heated, and contained within a protective atmosphere created by the products of combustion, which escape at the furnace ends, until the wire reaches to the die.

"' In'order that the furnace of the present invention may Y bolts, to the platform 14.

Fig. 4 is a vertical longitudinal sectional view of the wire drawing furnace along the line IV-lV of Fig. 2 in the direction of the arrows.

Fig. 5 is an enlarged fragmentary vertical sectional view vof one of the pivot points of afurnace elevating mechanism along the line V-V of Fig. 2 in the direction of the arrows and showing the operating lever thereof in its raised position.

VReferring now to the drawings, particulraly to Fig. l the reference numeral 10 designates a wire drawing ma.- chine, particularly adapted for the drawing of ne tungsten or molybdenum wire 12-and which is mounted, as hereinafter described in detail, on a table or platform 14;

The wire `drawing machine 10 has a reel 18 mounted on a suitable shaft projecting laterally from a bracket 20 upstanding from the table 14. This reel 18 carries the wire 12 which is to be drawn to a reduced weight and diameter by the machine l0. Adjacent to the reel 18 thevwire vpasses through -a lubricant cup 22 mounted on -a suitable holder V24 upstanding from the table or platform and into a wire drawing furnace 30 of the present invention. The wire drawing furnace 30 is mounted by means of a furnace elevating mechanism 31 on a bracket 32. The bracket 32, in turn, is secured as by `Near the exit end of the furnace 30 the Wire 12 passes through a drawing die head standing roller mounting bracket 48 may guide the nowv reduced drawn wire 12 from the `drawing die head 40 to a` reel or speoling head 5,0 where the drawn Wire 1s wound thereon in the usual manner. This -reel 50. is carried on a horizontal shaft 52 projecting from an up-Y standingbearing 54 and is reciprocably traversed on s-aid shaft 52 by a reel traversing mechanism (not shown). In addition to the reel 50 the shaft 52 carries a driven pulley S6, rotatable by suitable means, such as a belt 58 driven by a motor (not shown).

The elevating mechanism bracket 32 carries a channellike heat baffle 60` (Fig. 2), of generally shallow U-shaped vertical section, which extends substantially the length of the wire drawing furnace 30. and is juxtaposed therebeneath when said furnace 30 is in its normally down or operating position, shown in Figs. l and 2. The baffle 60.has lugs 61 (Fig. 2) on one of its longitudinal sidewalls for limiting the downward pivotal motion of the wire drawing furnace 30 from the upper non-operating position (shown in dotted lines in Fig. l) to the lower operating position.

Furnace lifting mechanism A pair of upstandi-ng pivot posts 62 of the wire drawing furnace elevating mechanism (Figs. 1, 2 and 5) project upwardly from the bracket 32. Each post 62 is provided with a shaftsupporting hub portion 63 which has a generally horizontal upper surface 66, as viewed in Fig. 5. A headed shaft or pin 64 extends through and is rotatable in the hub portionV 63 of each of the pivot posts 62. The shafts 64, as viewed from left to right in Fig. l, carry operating or furnace lifting levers 67 and 63 respectively. The lever-68 has a hub encircling mounting flange 69, as shown in Fig. 5, and is provided with a shoulder 70 of generally tapered contour. This shoulder 70 becomes engageablewith upper surface 66 of the hub portion 63 to limit the upward pivotable movement of the operating levers 67 and 68 and hence the wire drawing furnace 30 to the dotted line position shown in Fig. 1= which position is beyond the dead center position, as hereinafter explained.

Each of the operating levers 67y and 68 has an upper shaft hub which carries a headed shaft or pin 72 (Figs. 1 and 2) projecting through suitable arcuate slots in a stationary side baille 74. The baffle 74 is affixed to the heat baille 60, as bybolts which extend into a gas manifold 90-of the wire drawing furnace 30. It will be understood that the lever 68 is` of the bell crank type and carries (Figs. 1- andl 2) an operating handle 78 ('Fig. 2) projecting laterally therefrom,

It will be understood from a consideration of Fig. 1 that the levers 67 and 68 (pivoted on the upper ends of the pivot posts 62) and a body 80 of the wire drawing furnace 30 (pivotable on the shafts 72 carried on the upper hubs of thelevers 67 and 68) form a pivotable parallelogram and constitute the wire drawing furnace lifting mechanism 31. By means of the handle 78, the wire drawing furnace 30 can be swung counterclockwise (Fig. 1) from its operating position within the baffle 60 to its non-operating or wire loading position shown in the dotted lines of Fig. 1.

Wire drawing furnace 30 The metallic casting or body 80 (Figs. 3 and 4) comprises essentially an open topped box provided with wire entrance and exit clearance slots 82 in the end portions thereof and a longitudinal wire clearance slot 84 in the bottom face thereof which connects the end slots 82.

As shown in Figs. 3 and 4 particularly, a gas manifold 90 is secured by the flanged portions thereof and suitable bolts 92i (Fig. 3) to the body 80. Algas flow baille 96 is juxtaposed below a gas inlet connection 98 of the manifold 90 to circulate the gas to all parts of the manifold 90. The bottom mounting flange of the gas manifold carries adjustable stops 97 (Figs. 2 and 4) which engage lugs 61 on the baille 60 to limit downward motion of the furnace 30. This flange of the manifold 90 is suitably machined to provide a shoulder 99 (Fig. 3) for the positioning therein of a plurality of longitudinally stacked generally T-shaped burner tips 100 of suitable refractory material, such as a high grade fire clay, for example Kaolin, a trademark for a clay containing such high alumina minerals as kynite or anda lusite. A suitable retaining plate gasket 102 fits about the Shanks of the burner tips 100 between the flanged portions of the gas manifold 90 and a refractory retaining plate 104. secured to the flanged portion of the gas manifold 90, as by suitable bolts, not shown.

Each of the burner tips 100 shown in Fig. 4 has an inverted Y-shaped gas slot or port (Fig. 3) cut in one face thereof. It will be understood that the gas burner groove 110 in a given burner tip 10|)y rests. against the flat face of the next burner tipl 100 thus providing a gas port for the passage of the gas therethrough. lThe upper end of each gas port 110, as viewed in Fig. 3, leads into the gas manifold 90. The bottom aperture in each gas port 110 diverges the gas against a corrugated arcuate surface 112 of refractory reflectors 114, sui-tably of the same refractory material as the burner tips 100.

As shown in Fig. 4 the arcuate corrugated refractory reflectors 114 on either side of thevwire 12 comprise a series of sections fitted together in overlapping engagement. The corrugations 112 tend tol slow the flow of gas from the gas outlet portions of the gas ports 110. It will be understood that when the washboard surface of lthe reflector on either side of the wire 12 mayhave been heated, for example, to a white heat in the neigh borhood of 1500-2000o C. the gas tends to burn not only at the open gas port 110, but in an encircling arc which covers the entire corrugated surface of the reflectors. This V.provides uniform heat to the wire 12 passin through the wire drawing furnace 30. v

Between the longitudinal side walls of the casting or body 80 of the furnace 30 and the refractory reflectors 114, suitable insulating or packing material (Fig. 3) of a refractory nature, such as a high temperature bonding cement or refractory mortar containingkaoliny precalcined at a temperature over 3000 F., is providedfto insulate the refractory reflectors 114 from the sidewalls of the casting 80.

Die holder head The die holder head 40 (Figs. 1 and 2) has a generally hollow flanged die holder castingl secured', as by bolts, through the flanged portions thereof (Fi'g. 1) to the mounting projection 42 of the bracket 32. Insulating plates or spacers may be juxtaposed between theV projection 42 `and the casting 130. A die heater 1'32 (Fig. 11)'v suitably a burner having a curved upper end, is secured to the table 14', as by bolts, and projects upwardly through the generally hollow triangular vertical cross section of the casting 130. The flame of the burner 132 isdirected against a die holder block or a block-like por tion 134 of the casting 130.

' AS shown particularly in Fig. 2 the block 134, a portion of the casting 130, is siutably slotted on either side of the die holder retaining portion thereof to provide adequate insulation and protection to la heated die from drafts. The wire drawing die 140, maintained desirably at a temperature between 30G-400 C., is secured in the die holder retaining portions of the block 134; The right hand end of the block 134 when viewed in Fig. l, is suitably formed or machined to provide a generally frustoconical guide and clearance hole for the drawn wire 12 as it leaves the die 140 and enters the guide rollers 44 and 46.

Thus, it will be seen from the foregoing. description that the wire drawing furnace 30 of the invention has a hollow body 80, slotted at the bottom and at the ends to permit passage therethrough of the wire 12. Refractory arcuate corrugated reectors 114, secured in the side walls of the furnace 30, are gas heated by a plurality of burner tips 100. The tips 100 are arranged and stacked one behind the other along the longitudinal axis of the furnace, so that the flames therefrom sweep down the side walls of the reflectors 114 and the corrugations 112 thereon to first heat the side walls of the reflectors 114 to a white incandescence whereupon the gas burns along the entire periphery thereof.

The wire drawing furnace 30 of the invention permits the wire 12 to be completely enclosed within the body 80 and the bafe 60 and contained within a protective atmosphere within the furnace 30. The protective atmosphere is created by the products of combustion which circulate about the wire 12 within the wire heating chamber between the refractory reflectors 114. These protective products of combustion exit at the furnace end slots 82 and protects the wire 12 being heated within the wire drawing furnace 30 from oxidation etc. right up to the entrance of the wire 12 into the heated `die 140.

To facilitate the threading of the wire 12 over the guide pulley (not shown) at the entrance to the wire drawing furnace 30 and through the wire drawing die 140 at the exit end thereof, the furnace 30 is provided with a furnace elevating mechanism 31. This mechanism 31 swings the wire drawing furnace 30 backwards and upwards on two pivot posts 62 without jarring and thus avoids damaging the refractory reiiectors 114 or the refractory retaining plate 104.

The wire drawing furnace 30 of the invention uniformly heats the wire 12. Minor gas pressure fluctuations within gas manifold 90 do not affect the temperature of the wire 12. The heat baflle 60 below the wire drawing furnace 30 retains the heat within the refractory reflectors 114 thus reducing appreciably the amount of heat formerly required. This baille 60 also contains the protective atmosphere created by the products of combustion and prevents fluctuations in the heat within the wire drawing furnace 30 due to drafts. In addition, it is impossible for the burner tips 100 to become clogged due to aquadag falling thereon. Uniform temperature of the wire 12 which is assured by the wire drawing furnace 30 of the invention, provides longer life for` the dies 140, appreciably reduces breakage of the wire 12 thus eliminating the necessity for periodic Wire respooling. The furnace 30 also provides substantial gas savings in the op# eration thereof. As a result the quality of wire 12 in the form of uniform weight of Wire is improved and production in the form of total length of drawn wire 12 is increased.

Although a preferred embodiment of .the invention has been disclosed it will be understood that modifications may be made within the spirit and scope of the invention.

We claim:

1. A furnace for heating wire which is to be drawn through an adjacent die, comprising a heat baie adapted to retain heat within the furnace, contain the products of combustion within the furnace as a protective atmosphere for the Wire passing therethrough and prevent fluctuations of heat within the furnace due to drafts, a body normally partially contained within said heat baiiie and provided with a corrugated surface adapted to be disposed about said wire and adapted to slow the flow of gas thereabout, and means associated with said body for introducing gas to said corrugated surface and heating the latter to i11- candescence to cause the gas to burn along the entire corrugated surface thereby uniformly heating the wire.

2. A furnace for heating wire which is to be drawn through an adjacent die, comprising a heat baille adapted to retain heat within the furnace, contain the products of combustion within the furnace as a protective atmosphere for the wire passing therethrough and prevent fluctuations of heat Within the furnace due to drafts, a body normally partially contained within said heat baille and provided with a corrugated surface adapted to be disposed about said wire and adapted to slow the flow of gas thereabout, means associated with said body for i11- troducing gas to said corrugated surface and heating the latter to incandescence to cause the gas to burn along the entire corrugated surface thereby uniformly heating the wire, and means connected to said body and operable to move said body away from said heat baffle to permit the threading of the wire through the heat bale and into the adjacent die.

3. A furnace for heating wire which is to be drawn through an adjacent die, comprising mounting means, a heat baffle on said mounting means and adapted to retain heat within the furnace, contain the products of combustion within the furnace as a protective atmosphere for the wire passing therethrough and prevent fluctuations of heat within the furnace due to drafts, a body normally partially contained within said heat bae and provided with a corrugated surface adapted to be disposed about said wire and adapted to slow the ow of gas thereabout, means associated with said body for introducing gas to said corrugated surface and heating the latter to incandescence to cause the gas to burn along the entire corrugated surface thereby uniformly heating the wire, and means connected to said body and said mounting means and operable to move said body away from said heat bafe to permit the threading of the wire through the heat baffle and into the adjacent die.

References Cited in the le of this patent UNITED STATES PATENTS 706,031 Daniels Aug. 5, 1902 1,362,367 Talley Dec. 14, 1920 1,676,176 Biggert July 3, 1928 1,731,055 Marchev Oct. 8, 1929 2,187,785 Hoyt Jan. 23, 1940 2,215,080 Hess Sept. 17, 1940 2,325,950 Green et al Aug. 3, 1943 2,474,313 Hess June 28, 1949 2,489,244 Stalegs Nov. 22, 1949 2,621,914 Morgan Dec. 16, 1952 2,762,618 Johnson et al Sept. 11, 1956 FOREIGN PATENTS 119,334 Australia Dec. 21, 1944 883,374 France July 2, I1943 386,412 Great Britain Jan. 19, 1933

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