US2610926A - Method and apparatus for coating wire with lime - Google Patents

Description

3 Sheets-Sheet l INVENTORS C. R. CHA SE and GezonasLBuss,

fiefi'fialwey.

C. R. CHASE ET AL METHOD AND APPARATUS FOR COATING WIRE WITH LIME Filed Feb. 6, 1948 Sept. 16; 1952 p 2 QRCHASE Em 2,610,926 1 METHOD AND APPARATUS FOR COATING WIRE WITH LIME Filed Feb. 6, 1948 3 Sheets-Sheet 2 INVENTORS CIR. CHASE and GEORGE L BL I85} p 1952 c. R. CHASE ET AL 2,610,926

METHOD AND APPARATUS FOR COATING WIRE WITH LIME Filed Feb. 6, 194a 3 Sheets-Sheet s E as 30 0 27 INVENTORS .C/P. CHASE 6/70 GEORGE L BL /ss,

Patented Sept. 16, 1952 UNITED: STATES PATENT OFFICE METHOIT). AND APPARATUS FOR COATING 'WIRE WITH'LIME Charles R. Chase, Morrisville, and George L. Bliss, Yardley,.Pa., assignors to United States Steel Company, a corporation of New Jersey Application February 6,1948, Serial No. 6,708

This invention relates to the manufacture of wire and, in particular-,to the coating of wire or wire rod with a film of lime or the like and baking it thereon to facilitate reduction of the wire to smaller size by drawing it through dies.

Theobject'of the invention is to provide a method and apparatus for applying a highly uniform coating to wire in a'continuous manner. This we accomplish by introducing traveling strands of wire into a coating bath and drawing them upwardly therefrom and through a vertical oven, maintaining them freefrom contact-with supporting and guiding means until the adherent film of coating material has been thoroughly dried. While lime is referred to herein as the specific coating material contemplated, it will be evident that the inventionmay also be used for applying coatings or other solutions or suspen- SlOIlS. Y It has been the practice heretofore to coat wire with lime'after pickling, by dipping coils of wire in a tub or vat of slaked lime 'and'thenbaking them'to dry the coating. The'lime coating ap-- plied by this practice is usuallynot uniform. If the coil turns are at all tightly assembled,- the lime does not penetrate thoroughly'between them, and sometimes portions of the wire are left-bare. When the coils are deposited in the oven, furthermore, the lime film' adhering to the turns tends to run down to the bottom of the coil by gravity, leaving a coating-varying in thickness between adjacent-turns or different parts of the same turn. Unless agitated, furthermore, the lime bath tends to stratify as a result of settling of the suspended solid particles. Usuallythe only agitation afforded is that caused by'the immersion and removal of coils so that, even if a heavy coating be acquired by the wire while deeply immersed, only a thin coating will remain after removal of the coil through the upper layer of the bath.

We have invented a novel method and apparatus for coating wire in strand form by passing it continuously through a lime bath and drying or baking it while free from contact with adjacent strands or'any supporting or guiding means. The invention is particularly adapted for use in connection with continuous patenting'apparatus such as a furnace, a lead-bath for quenching and one or more pickle tanks for removing scale. In a preferred embodiment and practice of the invention, we run the pickled wire through a 'cold-' water bath after ithas been rinsed-in hot water, and then into a lime bath and around a sinker roll partly immersed therein. -Wecirculate the lime bath constantly to insure uniform solids con- TClaims. (o1. 117%115).

tent throughout and draw the wire upwardly therefrom-through a verticaloven of sufiicient height to'eifect rapid and complete dryingv of the adherent film of lime. When the wire emerges from the top of the oven, it passes around a guide sheave there'above and .thenoedownwardly to take-up blocks. The novel apparatus wev have provided for carrying out. our method includes a vertical oven fitted with heating means. and having slots at the top andv bottom adapted. for the passage of a plurality ofwires upwardly therethrough in spaced relation and freefrom contact with any part thereof. .The oven is suspended on trolleys for movement to an out-ofth-way position, to facilitate threading the wires through the apparatus and removal of the sinker roll when necessary. A door hinged at one side permits the oven to pass around and enclose the wires when threaded; This drying or baking appa'ratusis also disclosed and claimed in our 00-: pending application Serial No. 227,074, filed May 18, 1951, s for Apparatus for Coating Wire with Lime, which is a division hereofl 'I Our improved apparatus also includes a novel form of lime .tub with .a baffle. or dam adjacent the sinker. roll to direct. circulation of the. lime and a pump for effecting such circulation. V

A complete understanding of the invention may be obtained fromthe following detailed description and explanation which refer to the accompanying drawings illustrating a. preferred embodiment and practice. In the drawings:

.Figure 1 is a central vertical section (through the apparatus, parts thereof being shown diagrammatically; V Figure 2 is a plan view of the lime tub;

Figure 3 is a central vertical section there-. through, showing a portion of Figure l to enlarged scale;

Figure 4 i a vertical transverse section through the drying oven;

Figure 5 is 'a central vertical section through the oven showing a portion of Figure 1 to enlarged scale; 1

Figure 6- is a transverse horizontal section through the drying oven with parts omitted; and

Figure'lis a partial section showing a portion of Figure 5 to enlarged scale, illustrating the details of hinged dampers mounted on top of the oven. In describing the invention it will be convenient first to refer to the apparatus in detail and then to explain how it functions in perform ing the method." 7 Referring for'the moment to Figure 1 the ap- 3 paratus comprises generally a cold-water wash tank I0, a lime tub or tank II, a drying oven l2 and a group of take up blocks |3 driven by conventional means indicated diagrammatically at M. If the apparatus be installed in conjunction with continuous patenting apparatus, it will be disposed beyond the last acid pickling tank and the warm-water rinse tank I6 of the latter. In any event, a plurality of wire strands I! are drawn through the several pieces of apparatus successively in the direction indicated by the arrows, by the tension exerted by the take-up blocks. In moving from the tank l5 to the tank IS, the strands pass over guide rollers l8. Similar rollers are disposed between the tank l5 and the tank In and between the tank l0 and the tub II. In traversing the tank IS the strands pass under a hold-down roller |9 journalld therein. The tank I0 is provided with a holddown roller 20.

The tub H (see Figure Z and, 3) may be of any suitable construction, e. g., timbers bolted together, and is adapted to contain a lime bath, the surface of which is indicated at 2|. Holddown or sinker sheaves 22 are rotatable on a shaft 23 extending transversely of the tub and supported in hanger brackets 24 depending from the sides thereof. The sheaves 22 have V-grooves spaced axially therealong for receiving individually the strands entering the bath after passing over the guide roller I8 at the right-hand end thereof and maintaining them in spaced relation as they are drawn up from the bath through the oven I2. As clearly shown in Figure '1, the sheaves 22 have their greater portion immersed in the bath.

In order to maintain the bath of a substantially uniform character and prevent the settling out of the solid phase, we maintain a substantially constant circulation thereof along a predetermined path. To this end, a dam or bafile 25 is disposed transversely of the tub adjacent the sheaves 22. The dam extends upwardly. from a floor or deck 26. in the left=hand end' of the tub spaced a short distance above the bottom thereof. The dam is of such height that its crest is an inch or so below the surface of the bath. A centrifugal pump 21 driven by motor 28 has its inlet connected by a pipe 29 including a valve 30 tothe space between the dam 25 and the left-- hand end of the tub, above the deck 26. The outlet from the pump is connected by a pipe 3| including a. valve 32 to a header 33 extending across the left-hand end of the tub below the deck 26 and provided at its ends with nozzles 33 adapted to deliver jets longitudinally of the tub and close to the bottom thereof, as indicated at 34.

When the pump is in operation, it induces a circulation of the lime in the tub, as indicated by the dotted arrows, i. e., from left to right along the bottom of the tub, upwardly at the righthand end thereof and from right to left adjacent the surface of the bath, thence downwardly around the sheaves 22, upwardly between them and the dam 25 and over the crest of the latter to the outlet pipe 29. It will be apparent that the jets 34 create considerable agitation of the bath as it circulates through the right-hand end thereof. The portion of the bath between the sheaves 22 and dam 25 by comparison is-relatively quiescent. By reason of the circulation and agitation, all parts of the bath have substantially the same amount of suspended solid, in this case calcium hydroxide, the liquid being water. As a 4 result, the wire strands passing around the sheaves 22 and emerging substantially vertically from the bath acquire an adherent film of lime which is uniform among the several strands and from point to point along each strand.

The oven |2 (see Figures 4 through '7), through which-the strands ascend on emerging from the lime bath, is an elongated chamber disposed vertically, the walls of which are composed of suitable insulating or refractory lining |2 laid up in a binding composed of metal sheathing plates |2 secured to a frame of structural members l2. The bottom of the oven has an entrance slot 35 extending across the width thereof. The top of the oven has a similar exit slot 36. Tubular burners 31 extend across the width of the oven at the bottom thereof, one on each side of the slot 35. A pilot burner 38 with a spark-gap igniter extends through one side wall of the oven at a level slightly above the burners 31. The burners are connected to any convenient source of fuel gas through inspirator tubes and are provided with suitable control valves.

It will be apparent that the burners 31 heat the interior of the oven effectively by radiation and convection, the combustion gases passing upwardly through the'oven and out through the slot 35 maintaining a natural draft of secondary air through the inlet slot 35. This draft is controlled by damper plates 39 (see Figure '7) hinged to the top of the oven and having their free edges partially overlying the, slot 36. One of the dampers is composed of. two lapped sections adjustably connected by bolts passing through slots therein and provided with wing nuts. This permits adjustment of the extent to which the free edge of the damper overlies the outlet slot. The hinged mounting of the dampers permits them to swing upwardly to provide the necessary clearance in case they are engaged by a spllce joining successive lengths of a wire strand.

Before lighting the burners, the oven is purged of air by an exhaust fan 40 mounted on brackets 4| securedto one side of the oven. The inlet of the fan is connected to an outlet 42 in the oven wall and the-fan is driven by a motor 43 mounted onbrackets 4|.

The oven is mounted for traveling movement from aposition of the tub H, as shown in Fi ure 1, to an out-'of-the-way position laterally spaced from the tub, as indicated in chain lines inFigure 4. The oven is preferably suspended from beams 44 by brackets secured thereto and to the frame members of theoven binding. The beams 44 are carried by hanger rods 46 depending from trolleys 41. These trolleys are adapted to travel along spaced rails 48. The rails may be supported in any convenient mane ner. In Figure 1 they are illustrated as secured to cantilever beams 49 extending laterally from a supporting framework 50 of structuralm'embers. If the roof trusses of the building in which the apparatus is installed are of sufficient ca:- pacity, however, it is usually more convenient to suspend the trolley beams directly therefrom. The mounting of theoven 2 for lateral'movement- .to an out-of-the way position facilitates threading the wire strands through the 'appa ratus and gives ready access to the tub H for removal of the sheaves 22 when necessary. In order to permit the 'oven to clear the wire strands when properly threaded, one side wall is in the form of a hinged door 5|, as shown in Figure 6. The entrance and exit slots 35 and 36 ex- .tend through the edge of .the bottom and di of the oven, respectively,.-=onthe side on which theactuating chain 5.2 is provided. having its ends secured to a gusset 53 fastened to, one of the beams 44 andtrainedaround spaced sprockets 54. mounted on'shafts journalled on the rails. 48. The. shaft of the sprocket nearer vthecentral plane through the lime tube also has a sprocket.

55 thereon around which an endless operating chain, 56 is trained. This chain is of such len th. as to hang down within reach of an operator.

standing on the floor. Y

Guide sheaves '51 having 1v-groovespspaced axially therealong are disposed above the oven;

l2v and .are adapted to-receive the wire. .st-rands emergin therefrom andsupport them as .they; travel downwardly toward the takerup blocks l3.

In using the apparatus described above in theperformanceof our novel method, a plurality of wire strands I! are introduced into the lime bath 2| in tub II. Total immersion is effected by guiding the strands into the bath over and around the supporting roller 3 at the entrance thereof and under and around the hold-down or sinker sheaves 22. As shown in'Figure 1; the angle madeby the entering strands with the surface of the bath is less than/l5". The bath is maintained at a temperature of from 130 to 220 F. by any convenient heating means, such as immersed steam pipes and preferably has a solids content of from 8 to In case the wire to be coated is delivered directly from a continuous patenting apparatus, the cold-water wash tank [0 is preferably supplied with water at a temperature of from 50 to 60 F., inorder to improve the adherence of the-lime to the wire as it passes through and out of the bath.

After passing around sheaves 22, the wires travel upwardly from the bath through the drying oven [2. By drawing the wire strands vertically from the bath in a portion thereof which is relatively quiescent, i. e., the space between sheaves 22 and the dam 25, the adherence of a film of maximum thickness for the existing solids content of the bath is assured. Since the bath is of substantially uniform character throughout, there is no tendency for the film to be partly washed off or diluted as the wire emerges from the bath. The reduced velocity of the bath adjacent the point of emergence of the wire strands,

furthermore, tends to prevent the film disposed on the wires from being washed therefrom. As the wires ascend vertically from the bath, any excess lime adhering thereto runs downwardly along the wires by gravity, thus tending to render the density of the film uniform at all points along each wire.

. The film adhering to the wire strands is dried and baked as they pass upwardly through the oven [2. The oven is preferably maintained at about 400 F. although this temperature may be varied considerably. An oven operated at this temperature is capable of satisfactorily drying the lime coating on wire passing therethrough at speeds of about 100 ft. per minute. It will be observed that the strands are maintained in spaced-apart relation to each other and free from coatingwire. with lime.-

6. contact with any guiding or supporting means: during their ascent through; the oven. The; strands are stretched between the sinkersheave's 22 and the guiding sheaves 51 so that "the filni of lime adhering tothe wires .as theyTpa'ss-around" the former and upwardly out of the bath is fullydried and baked on by thetime the latter is enaged. In fact, ;,the drying and baking are effected to an extent suchthat. the bending of the wires around the sheaves 51 does not cause any noticeable-flaking off of the coating. 1

It will be apparent from. theforegoing thatthe invention herein disclosed is characterized by." numerous advantages over the priorpractice' of. In. the. first place,= the invention makes it possible to apply a lime coating. of much greater. uniformity than is obtain-" able with. the method used heretofore. EaCh pointof each wire strand is subjected to practically identical conditions of limenplck-up and drying and thereis no contact with the wire between final emergence from the coating bathand complete. drying of the adherent fi1m.- As are sult, bare or uncoated spots on the wire strands are wholly. eliminated. By reason of the unland finish to that madeof'wire-Iimed-by the batch process. This results from the fact that the absence; of bare spots prevents bright spotson the. finished wire which are subject to scratch ing. The coatedwire is delivered directly from the sheaves above the oven to thetake-up mocks,

thus eliminating the possibility of abrasion by contact with. intermediate guide rollers. a

The advantage of the traveling mounting of the drying .oven.in facilitating threading and givingready accessito the sinker sheaves has already beenmentioned. -The construction and arrange ment, of thelime tub and the continuous circu lationiof. the. bath contribute-in an obvious man ner to the application of a highly uniform coating to the wire strands traversing it. The tub and drying oven, furthermore, are of simple construction so that their initial cost is not large and. the maintenance thereof almost negligible.

Although we have illustrated and described but a preferred embodiment and practice of the in-- vention, it will be recognized that changes in the: arrangement and details of construction and. operation may be made without departure from. the spirit of the invention or the scope of the ap-- pended claims.-

We claim:

1. In a method of coating wire with lime, the: steps including drawing wire over one end of a. tank containing a lime-coating bath, along a. downwardly sloping path beneath the surface of". the bath and upwardly around a guide sheave spaced from said end and partially immersed in. said bath, withdrawing liquid and the solids sus-- pended therein by suction from the upper portion of the bath at a point beyond said sheave in the direction of wire travel, and substantially below the surface thereby maintaining said surface substantially quiescent, re-introducing the withdrawn liquid and solids on the same side of said. sheave as said point of withdrawal, as a jet under pressure directed along and substantially parallel. to the bottom of the tank in a direction opposite the general direction of travel of the wire, there-- by inducing return flow of the liquid and sus- Z pended solids along theupper portion 01'- the bath generally parallel to the entering wire and in the direction of travel thereof and causingthe return flovLof liquid and suspended solids to pass around the'hottomof said sheave and generally upwardly towardLthe surface of thebath before reaching said point of withdrawal.

v 2. Apparatus for coating wireflcomprising an elongated tank adapted to contain a coating liquid, a guide sheave journaled transversely therein around which the wire travels into and out of the liquid, an outlet at one .end of thetank spaced above the bottom thereof and at a point beyond the sheave in the direction of wire travel, a nozzle at said .end adjacent the bottom directed longitudinally of. the tank, pump means connected between said outlet and said nozzle and flowdeflecting means adjacent .the sheave causing the liquidapproaching said outlet to flow upwardly around the sheave.

r 13.. The apparatus defined by claim 2 characterized by said lastvmentioned means comprising a battle wall disposed transversely ofthe tank between said sheave and said outlet and extending downwardly from a level .below the top of the ten'kand a deck extending transversely of the tank iron: saidbafile wall to said end, said deck being disposed at a level between said outlet and said-J t.

.4... :In a method of coating wire with iii-me, the steps including drawing wire over one end of a containing .a lime-coating bath, along a downwa-rdly sloping path beneath the-surface of wire and causing the return flow of liquid and suspended solids to pass around said sheave and.

upwardly toward the surface of the bath before reaching said point of withdrawal.

5. Apparatus for/coating wire comprising an elongated tank adapted to contain a coating liquid, 2. guide sheave iournaled transversely therein, anv outlet at one end .of the tank spaced above the bottom thereof, a nozzle at said one end adjacent the bottom of the tank adapted to discharge a jet toward the other end thereof, pump means connectedbetween said outlet and said nozzle .and flow-deflecting means causing the liquid approachingsaid outlet to flow upwardly around the sheave.

6. The apparatus defined by claim 5 characterized. by said lastsmentioned means being a battle wall disposed transversely of the tank be.- tween said sheave and said outlet and extending downwardly from a level below the top of the tanln.

7. The apparatus defined by claim 6 characterized by a deck extending transversely of the tank from said baflle wall to said end, said deck being disposed at a level vbetween said outlet and said jet.

, CHARLES R. CHASE.

GEORGE L. BLISS.

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

UNITED STATES PATENTS Number Name Date 1,342 11 Peter V.- a 93 1,947,993 Larsen Feb. 20, 1934 1,961,667 Johnson June 5, 193.51 2,154,057 Thielking Apr. ,11, 1939 2,235,82 a ved-na M r- 25, v --.-.-f M t -..-.--.a--:-- 232 24. 3 .E ksso Ave 2. .19

Claims (1)

1. IN A METHOD OF COATING WIRE WITH LIME, THE STEPS INCLUDING DRAWING WIRE OVER ONE END OF A TANK CONTAINING A LIME-COATING BATH, ALONG A DOWNWARDLY SLOPING PATH BENEATH THE SURFACE OF THE BATH AND UPWARDLY AROUND A GUIDE SHEAVE SPACED FROM SAID END AND PARTIALLY IMMERSED IN SAID BATH, WITHDRAWING LIQUID AND THE SOLIDS SUSPENDED THEREIN BY SUCTION FROM THE UPPER PORTION OF THE BATH AT A POINT BEYOND SAID SHEAVE IN THE DIRECTION OF WIRE TRAVEL, AND SUBSTANTIALLY BELOW THE SURFACE THEREBY MAINTAINING SAID SURFACE SUBSTANTIALLY QUIESCENT, RE-INTRODUCING THE WITHDRAWN LIQUID AND SOLIDS ON THE SAME SIDE OF SAID SHEAVE AS SAID POINT OF WITHDRAWAL, AS A JET UNDER PRESSURE DIRECTED ALONG AND SUBSTANTIALLY PARALLEL TO THE BOTTOM OF THE TANK IN A DIRECTION OPPOSITE THE GENERAL DIRECTION OF TRAVEL OF THE WIRE, THEREBY INDUCING RETURN FLOW OF THE LIQUID AND SUSPENDED SOLIDS ALONG THE UPPER PORTION OF THE BATH GENERALY PARALLEL TO THE ENTERING WIRE AND IN THE DIRECTION OF TRAVEL THEREOF AND CAUSING THE RETURN FLOW OF LIQUID AND SUSPENDED SOLIDS TO PASS AROUND THE BOTTOM OF SAID SHEAVE AND GENERALLY UPWARDLY TOWARD THE SURFACE OF THE BATH BEFORE REACHING SAID POINT OF WITHDRAWAL.

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