US2311616A - Apparatus for treating metal strips - Google Patents

Description

Feb. 16, 1943. R. H. GORDON ETAL APPARATUS FOR TREATING METAL STRIPS 3 Sheets-Sht 1 Filed Feb. 15, 1940 11v VENTORS aribz F0};2"Z 7% 7. 7E0%e."

I %\ATTORNE Feb. 16, 1943. R. H. GORDON EIAL APPARATUS FOR TREATING METAL STRIPS Filed Feb. 15, 1940 1 5 Sheets-Sheet 2 4? Z INVgNTO/E E. 0 er Fag F 16. V Wagmiys.

Feb. 16, 1943.

R. H. GORDON ETAL ,3 1,616

APPARATUS FOR TREATING METAL STRIPS s sheets-she t 3 Filed Feb. 15, 1940 [N VE N T0195. ar i'a )7, 7, 7'dofe. y %\ATTORNEY$ Patented Feb. 16, 1943 UNITED STATES PATENT OFFICE 2,311,616 APPARATUS Fortrnrarmo METAL s'rairs Robert H. Gordon, Detroit, Mlcla, and Roy P. 'looke, Butler, Pa, assignors to The American Rolling Mill Company, Mlddietown, Ohio, a corporation of Ohio Application February 15, 1940, Serial No. 319,114

a 4 Claims. (Cl. 266-43) The present invention relates to improved apparatus for processing strip steel, and particularly relates to improved apparatus or applying rust-proofing solution to such strip steel.-

It has been the practice in strip steel mills to store the strips in the form of coils outside of the mills where such coils are exposed to the elements with the result that they become rusted.

One of the primary objects of the present invention is to treat the surface of strip steel so that it may be stored outside in coils and will not rust when exposed to the elements.

Another object of the invention is to provide an apparatus by which strip steel may be continuously cleaned and thereafter treated to proprovision of means for keeping the strip moist until it enters the coating bath,,whereby it is insured that the coating will be evenly distributed over the strip.

Another object of the invention is the provision of mechanism which insures that the strip, upon its emergence from the coating bath, will not carry along an excess of the coating fluid, whereby streaking and imevenness in the thickness of the coating is eliminated.

Another object of the invention is the provision of means whereby the rust-proof coating SQlution duce coatings on the surfaces thereof to render such surfaces rust-proof.

Another object is to provide an improved dry- Y ing oven whereby the strip steel may be efliciently subjected to heat after the rust-proofing solution has been applied thereto in order to quickly dry j the same.

Another object of the invention is to provide an improved arrangement of a. cleaning bath, a rinse, a bath of rust-proofing solutions, a drying oven and means for continuously carrying a strip of steel through these elements so that the surfaces of the strip may be rapidly and economically rust-prooted.

Another object of the invention is to provide an improved arrangement of a cleaning bath, a rinse, a pretreating or flash bath, a. rinse, a bath of rust-proofing solution, a drying oven and means for continuously carrying a strip of steel through these elements so that the surfaces of the strip;

may be rapidly and economically rust-proofed.

Another object of the invention is to provide a machine for carrying out a'coating process of the nature above discussed, in which the successive operations are carried out upon the strip automatically and continuously without the intervention of human hands.

. Another object of the invention is the provision of an apparatus as above outlined in which the diilerent variable factors involved, such as the treatment times in the various successive steps, may be closely controlled, to the end of producing a perfectly coated strip.

Another object of the invention is to provide an arrangement, whereby excess so lution is rinsed of! the strip immediately upon its emergence from the pretreating bath in order to avoid drying of such excess solution upon the strip. I A further object ofthe invention involves the on the strip is dried as rapidly as possible and prior to contact of the strip (after leaving the coating solution and after excess solution is removed) with any conveying means.

A further object of the invention resides in the arrangement of the elements whereby the strip, after it issues from the last bath, is dried before it is engaged by any of the conveying means within a baking oven, whereby the coating is not in- Jared in any way by such engagement.

Another object of the invention is the provision of means whereby the processed strip istreated prior to its coiling so that such strip and the coating thereon will not become injured by the subsequent coiling operation.

A further object of the invention is the provision of cooling means so located that as the relatively hot strip issues from the baking oven, it is cooled to such a temperature that it may be coiled m. 2 is a plan view alons' thelinel-I oi'I'ig. 1 H

Fig. 3 is a side ,elevational viewtaken in the direction of the arrows H in 1111f,v

flgJisadetaiLpartialeleva onal'viewoia bearing mounting for one or the conver s mils in the baking oven, taken axially of theroll;

1'18. 5 is an elevationalview taken from the 113130! FIIJ; v it: Fig. 6 is a fragmentsrrperspective view of a portion of the strip steel which is processed by the apparatus illustrated in Figs. 1 to 3;

Fig. 7 is a view similar to Fig. 1, illustrating a modified, preferred form of the present invention; and,

Fig. 8 is a top plan view of the oven and heating means illustrated in Fig. I.

According to one embodiment of the present invention, a coil of strip steel is disposed adjacent the processing apparatus, and the leading end thereof is first carried through a pre-treatment container which has a suitable cleaner therein for the purpose of removing any grease or dirt on the surfaces of the strip. The strip is then carried through a cold water rinse so as to wash any of the cleaning solution on the surfaces of the strip therefrom and then into a tank or container having the rust-proofing solution therein. The strip is then carried through a drying oven and passes from the drying oven onto a spool where it is re-wound into a coil.

Referring to Figs. 1 through 6 of the drawings 7 for a more detailed description of one embodiment of the invention, the coil ill of strip steel I2 is supported on a spool I having a standard It. The strip I2 is preferably a coil of strip steel which has been cold reduced, box annealed, and finally temper rolled. The parts forming the processing apparatus may be suitably mounted on a suitable framework, and such apparatus includes a pre-treatment tank or container I! which may be lead lined or constructed of stainless steel, or other acid resistant material for pretreating the strip prior to its treatment in the rust-proofing bath.

A housing 20, having a cover 22 associated therewith and provided with an inlet 24 and an outlet 26, is disposed adjacent the tank I! at substantially the same level. Cold water rinsing means, including oppositely disposed pairs.

steel as it is passed between the pairs of pipes.

to wash any pro-treating solution carried by the surfaces of the strips therefrom. The water is collected in the bottom of the housing and may be drained therefrom in any suitable way.

Another tank or container 34 is disposed adiaoent the container 2| at substantially the same level and is adapted to contain thereinthe rustpmoflng solution. The rust-proofing solution may be such as that disclosed in the McDonald Patent No. 2,030,601, February 11, 1936, and is such that a corrodon resistant, paint holding coating is formed on the surfaces of the strip of steel as it is passed through the oven. The solution may be maintained at substantially room temperature. If it is desired to raise the tem-. perature, this may be done in any suitable way such as by the immersion of steam or hot water plpesinthebath.

The pie-treatment tank. ll. the rinsing means includes insulated walls forming the oven enclosure. Suitable doors and 40 may be provided in order to provide access to the interior I of the oven.

A transversely elongated inlet opening 42 is provided through the bottom wall of the oven 38 immediately above the tank 34 adjacent one side of the oven; and a transversely elongated outlet opening 44 is provided through the opposite wall adjacent the bottom thereof.

As the strip leaves the rust-proofing tank 34, it passes between a pair of idle rollers 48. The purpose ofsuch rollers is to provide for the even distribution of the coating solution on the strip and to insure that excess solution on the strip is not carried into the baking oven. It is a characteristic of the present process that the coating must be thoroughly dried on the strip before it touches any conveying mechanism in order to avoid marking of the strip. Likewise,

excess solution carried along with the strip tends to run and cause streaking. f

According to the broader aspects of the present invention, smooth surface rollers have been found to be satisfactory, but it has been found that for best results such rollers should have a roughened surface such as that disclosed and claimed in the copending application of John E. Eckert, SeriaLNo. 319,115, flied concurrently herewith. These rollers engage the strip and serve to control the amount and distribution of the rust-proofing solution thereon immediately prior to the entrance of the strip into the oven, so that the strip is in proper condition for the baking treatment it receives in the oven. A rustprooflng coating of substantial and uniform thickness is thereby ensured. a

Heating means are associated with the oven and such means include a gas fired air heater 46 which. may be supported on the apparatus' framework above the level of tanks ii and I. An outlet conduit 48 communicates with the interior of the heater 4. and communicates with the interior of a fan housing II. The

fan housing is adapted to have a centrifugal fan mounted therein on a drive shaft 52; The drive shaft 2 may be mounted in suitable bearingqand has a drive pulley I4 assoposedinletconduitsilateachsideoftheonm,

respectively. The conduits I. extend along the sides of the oven adiaoentthe bottom thereof -andtewiththeinterloroftheovui through longitudinally spaced inlet openings 02. Thehotgasesarethusintroduoed intothcoven adjacent the bottom thereof, at each side. and at longitudinally spaced points.

Outlet openings areprovided through one side walloftheovenlladiaemtthetopthereofat longitudinally spaced points and communicate II, and 'the 'rust-proo'flng tank 34, are at substantially the same level and are aligned in a substantially straight line so that the strip of steel may be conveyed into and through each with a longitudinally extending conduit 04 having a downwardly extending portion M which communicates with the interior of the heater ll. 'lhohotgalesmaythuabere-circulatedthmgh wall of the oven 36 and communicates with the interior thereof so that the hot gases may be vented from the oven if desired. A damper I is associated with the conduit 66 so as to provide a control for the hot gasesexhausted from the oven. The oven is maintained at a temperature of approximately 650 F., for example, and the re-circulating conduits, together with the ventilating conduit 68, provide an effective and efiicient means for controlling the oven temperature along with the controls for the gas heater 46. The inlet and outlet conduits and the heater 46' with the housing 50 are suitably insulated.

Conveying means are provided for continuously carrying the strip of steel through the apparatus so that the intended processing may be eflected and are so operated that the proper time interval for treatment at each stage is possible. Such conveying means includes a plurality of drums or rolls 12, I4, I6, I8, 80, 82, 84, 86, 88, 90, 92, and 94. The drums are mounted on shafts which. in turn, are journaled in bearings on the framework. or. in the case of the oven rolls on' framework associated with the walls of theoven. Certain of the rolls-are driving rolls and others idle rolls, as will be pointed out hereinafter. The rolls are all constructed with annular flanges 96 at the sides thereof, and the space between the flanges is of substantially the same width as the width of the strip steel I2. The flanges 96 prevent displacement of the strips from the rollers and insure alignment of the strip as it is passed through the various stages of the process. Rolls 12, 14, I8, and 94 are driven rollers, while the remaining rolls are idle guide rolls arranged in a particular manner to be described hereinafter.

In connection with the arrangement of the rolls above described and shown in the drawings, it is pointed out that one of the important features of this arrangement resides in the position of the roll 82 with respect to the inlet to the oven. As mentioned above, it is important that the rustprooflng solution on the strip be dried before it contacts or engages any of the conveying elesprocket on a drive shaft IOI. extends longitudinally of the apparatus and may be iournalled in suitable bearings at spaced points therealong. Shaft IOI isoperatively connected ments disposed within the oven. It will thus be seen that roll 82, which is the first of the conveying elements engaged by the strip. is disposed at a position remote from the inlet 42. The roll is thus so arranged that the strip travels a substantial distance within the oven before it engages any of the conveying means, and by the time the strip reaches roll 82, the rust-proofing solution is dried sufliciently that it will not be injured by its engagement with the roll.

In the above description, it will be noted that the conveying rolls or drums are provided with flanges 96 in order to prevent displacement of the strips from the rollers and to ensure alignment of the strip as it is passed through the various stages of the process. It has been found, however. that the preferred means for attaining this end, that is, the proper alignment of the strip and the prevention of displacement of the strip from the rolls. is that disclosed in Figs. 4 and 5. This is accomplished by tilting certain of the conveyor rolls transversely of the strip. Preferably, the tlltable rolls will be. the first and last rolls contacted by the strip during its course through the baking oven. The tilting of the rolls is accomplished by mounting the rolls in the manner described and claimed in the copendlng application of Grant A. Pettit, Serial No. 319,116, filed concurrently herewith.

When the tiltable mounting for the rolls, disclosed in Figs. 4 and 5, is used the rolls having flanges thereon may be used, or smooth rolls without flanges may be used, as desired.

Referring to Figs. 4 and 5 for a description of this construction, an exemplary mounting for the bearing at one end of the roll 82 is illustrated. The wall of the oven is indicated in broken lines at I28 and the shaft I29 of the roll 82 projects through the oven wall as illustrated. The end of shaft I29 has its bearing in an adjustable element I30, and a seat collar I3I is provided adjacent each end of the shaft to prevent axial movement thereof. A portion of a frame structure is indicated at I32, to which are fixed guide rails I33, in which the element I30 is mounted for sliding movement. Fixed to the element I30 is a threaded member 134 which passes through a nut I35 mounted in a cross bar I36 fixed to the bottoms of the guide rails I33. It will thus be clear that as the nut I35 is turned. the slide I30 slides with respect to the guideways I33 and thereby vertically shifts that end of shaft I29.

The bearing at the other end of the shaft may be fixed and, since the ultimate in upward and downward movement of the bearing I30 will amount to approximately one-half inch, it is sufllcient to prevent binding if the fit of.element I30 and the guide rails I33 is relatively loose. The hearing at the fixed end of the shaft may be given adequate clearance to allow for this small tilting movement. It is to be understood, however, that the bearings at each end of the shaft may beof the self-aligning type or may be mounted in swiveling mountings.

The driving means for the rolls includes a pr ime mover 96 suitably connected by a belt and pulley to a speed reducer 98. The speed reducer 98 is connected through a' sprocket chain 99 to a The shaft IOI through suitable gear mechanism to feed reduction transmission mechanisms I02, I04, I06, and

' I08. The mechanisms I02, I04, I06, and I08 are operatively connected to the drive shafts for drums I2, 94, I4, and I8, respectively.

The strip I2 is disposed over the drums I2, I4,

and 94; and so that the strip is frictionally urged against the drums and may be frictionally driven thereby, a pressure roller H0 is associated with each one of these drum and engages the upper surface of the strip I2 at the top ofeach drum. Each friction roller I I0 is adapted to be mounted to a vertically movable slide member H2 which is slidably disposed within vertical guides II4.

A spiral spring II6 engages'the top of the slide H2 and is telescopically received over the lower end of an adjustable screw 6' which is threadably-received within a threaded mounting member H8. The member II8 may be fixed to the guideways II4. By adjusting the screws. 6'

the pressure exerted by the rollers 0 may be varied J The strip of steel I2 passes over the top of drum I2 and drops into the pre-treating bath within container I8. The strip then passes upwardly out of the bath so that a good portion of the pre-treatingsolution may drain back into the bath, and then passes upwardly over roll 14 and downwardly and under guide roll 16. Roll I8 is disposed at a level above roll I6 so that the strip I2 passes through the outlet 26 over roll.

16 at an angle upwardly disposed towards the outlet and in so passing within the housing 26 passes between the jets of cold water issuing from the pipe 26. The jets of cold water impinge against opposite sides of the strip l2 and wash any of the pre-treating solution remaining thereon from the surfaces of the strip. Due to the inclination of the strip, any water carried on the surfaces of the strip will drain back into the housing.

The strip I2 is then passed downwardly under guide roll 66 into and through the rust-proofing bath within the container 66. The roller 86 is journalled in bearings which are slidably mounted within guide members I26. By vertically adjustlng the position of these bearings, the tautness of the strip I2 may be effectively controlled, and also the interval of time it remains in the rust-proofing solution.

The strip I2 then passes between the rolls 66, through the inlet 62 into the oven 66, and in being carried upwardly out of the bath within the container 66 the execs rust-proofing solution will drain back into tank 66 below rolls 66.

The strip I2 is then trained over the guide rollers 62, 66, 66, 66, I6, and 62, so that the strip follows a tortuous path within the oven 66 and is thereby subjected to a complete drying operation. Roller 62 is disposed adjacent the outlet openingus'othatthe strip I2 ispassedthrough the opening 66 and engages roller 66 with its associated pressure roller III to convey the strip from the oven. The strip is then coiled on a suitable spool I22 mounted on standards I26 and at the completion of the process such coil may be stored out of doors. Suitable means may be provided for turning the spool I22 in order to coil the strip.

' Referring to Figs. 7 and 8 of the drawings, the preferred embodiment of the present invention is illustrated. It has been found that the Strip of steel I2, to betreated'accordingtothe present invention, is not free of dust, grease, dirt, or other foreign material so that it must be cleaned prior to treatment in order to accomplish the best results. According to this embodiment of the invention the stripisflrst cleanedbypassingit through analkalibath, then thoroughlyscrub- 'bingandrinsingthestripbeforeitispassed through the pro-treatment and final treatment baths. Although the alkali bath provides the preferable and most satisfactory cleaning means, other cleaners would be satisfactory. For exam.

' ple, vapor demeans, or an acid cleaner could be used, although it has been fund that good results are obtained with the alkali bath mentioned above.'"

Also, the material-is at relatively high temperatures. ,The. particular oven temperature used, in order-to obtain'the particular strlp temperature desired depends upon a number of variable factors, such as g uge and width of the strip, the coating desiredythe coatingsolution used, and the length of baking time. The strip according to the present invention, adjacent the I52 with a cover portion I56. The tank I62 is adapted to contain an alkali bath I 66 which is preferably maintained at a temperature of degrees to degrees F.

A roll I 58 is suitably mounted within the chamber above the bath and the strip I2 is adapted to be passed thereover. Rolls I66 and I62 are suitably mounted and are disposed so that the bottoms thereof extend within the bath I66. The strip I2 is then trained'around rolls and I62 so that it p through the bath Another roll I66 is mounted above the bath and is located at a level above the roll I66. and the strip I2 is passed therearound and passes between a pair of wringer rolls I66 which engage the surface of the strip for a reason to'be pointed out hereinafter. Spray means I66 extend transversely of'the strip I2 and are disposed above the bath I66 between and adjacent the rolls I62 and I66. Such means I66 may be in the form of tubes having a plurality of small apertures formed in the wall thereof and may be connected to the bath I66 through suitable conduits with a pumping means therewithsothatthealkaliofthebathispumped' I therein. The water in the bath I16 is preferably travels some distance after leaving the oven before it -is re-coiled, but with strips of certain widthsandthicknessesthereisnotasuillcientreduction in temperature between the time the strip leaves the furnace and thetime-it reaches the re-coil reel. It has also-been found that when the strip is coiled at temperatures exceeding approximately 390 1!, therein grave danger in injuring the coating thereon as the strip is coiled.

maintainedatatemperatureofa v 200 degrees F. Theoover I66 extendsoverthe bathiflandthechamberabovethealkaiibath I66 and the chamber above the water bath I16 areseparated fromeachotherbymeansofa Me or wall I" which extends' betwem t1 sides ofthechamber enclosingsuch tanks.

Itwillbeseenthattherollslflaredisposed move any of the dirt or alkali which may be.

thereon.

Wringer, rolls I83 are mounted for rotation about horizontal axes adjacent the outlet I80 and engage opposite sides of the strip I2 Just as it leaves the chamber above the water bath so that any excess water is removed from the surfaces of the strip. r

The, strip I2 is then passed through a pretreatment or flash tank, indicated at I90. Such tank contains a solution I92 whichwill coat the. steel strip. This preliminary coating may be an oxide coating, or other coating which, when' treated with the final treatment solution, will give, after baking, a corrosion resistant, paint holding coating on the strip. A roll I94 is mounted for rotation about a substantially horizontal axis above the bath I92. The roll I94 is so positioned that the lower end thereof projects below the surface of the bath at such a location and to such a depth that the strip I2 is immersed.

in the bath I92 before it contacts roll I94. Both surfaces of the strip are, therefore, wet by the solution I92 before the strip contacts roll I94.

, The strip I2 is trained about the roll I82 and also about the roll I94 so that the strip passes into proofing tank 208. The tank 208 corresponds to the tank 34 above described and contains a rustprooflng bath 2I0, similar to the bath mentioned above in connection with tank 34, or other solution, which when applied over the preliminary coating will give a corrosion resistant, paint holding coating on the steel strip after baking. Rolls 2I2 and 2, corresponding to rolls I8 and 60 in the embodiment above described are mounted in a similar manner with respect to tank 34.. The strip I2 is passed around these rolls into and through the bath 2 I 0 and passes upwardly therefrom into the baking oven 2I6.

So that the strip I2 is wiped free of any excess water which is carried thereon from the rinse chamber 20I, wiper members 2 I8, similar to wip ing members I96, are disposed adjacent the outlet 206 in such position that they bear against the strip. 7

Rolls 220, similar to the rolls 43 described in the above embodiment, are disposed above the bath 2I0 in a position similar to that described above in connection with tank 34 and serve the in the embodiment described above as shown in Fig. 1. The rotating brushes and the wipers,

such as I96, may be suitably mounted on the same framework.

the bath I92 for the pre-treatment effected by this bath. Before the strip reaches the bath, transversely extending wiper elements I96 are mounted to suitable framework so that they press wainst opposite sides of the strip and serve to wipe the strip free of any excess water remaining thereon before the strip passes into the bath.

Such members I96 are formed of such material that they will perform a wiping action on the strip without in any way marring the surface thereof. For example, they may be constructed by wrapping a strong, rugged material, such as canvas, in a plurality of layers about a suitable supporting element, or they may be formed of a strong, rugged felt material.

The strip then passes from the tank I90 through an outlet I98 into a rinse chamber 20I. Spraying means 202 in the formof tubular members having outlet apertures therein are disposed on opposite sides of the strip I2, transversely thereof, with the openings so positioned that sprays of water are directed against both sides of the strip. Such spray means are placed in communication through suitable conduits, with a source of water, which may be at room temperature, having a pumping means associated therewith so that the spray is in sufficient quantities Q and at high enough pressures to accomplish a thorough of the strip. Wiper members 204, similar in'construction to the wiper members I96, are disposed adjacent the opening I98 and bear against opposite sides of the strip so as to wipe the major portion of the solution from bath I32 from the strip.

The strip is thoroughly rinsed in chamber 2M and it will be seen that it passes therethrough following anpupwardly inclined path so" that the water drains back into the chamber 20I. The strip leaves the chamber through an outlet 206 and is. then passed into and through the. rust- A drying oven 222, generally similar to the oven 36 above described, is supported on suitable framework above the rust-proofing tank 208 and includes insulated walls forming theoven enclosure. Suitable doors are provided in the oven walls for providing access to the interior thereof. The oven 222 includes an inlet 224, corresponding to the inlet 42, above described, which is disposed substantially vertically above the path between rolls 220. The oven also has an outlet 225 corresponding to the outlet above described.

Conveyor rolls 226 and 228 are disposed within the oven and are preferably mounted therein in the same manner as rolls 82 and 92 described above in connection with Figs. 4 and 5. A wall member 230 is disposed within the oven 222 in spaced relation to the left hand wall thereof (viewing Fig. 7) which extends across the oven 222 to provide a vertical conduit 232 which forms an initial drying chamber.

Heating means are associated with the oven and such heating means include a gas fired heater 234 having a burner 236 associated therewith. An outlet conduit 236 communicates with the heater and communicates with a blower housing 240 which has a suitable blower mounted I and 252.

Viewing Fig. 8, it will be seen that the outlet conduits 248 and 250 communicate with the drying chamber 232 of the oven on opposite side's of the strip I2. The outlet 252 communicates with the other portion of the oven to the right of wall 230 (viewin'g Fig. 8). An outlet for theoven is illustrated at 254 and communicates with a return conduit m. The return conduit returnsto the heater 2 for re-circulation of the heated For temperature control, a branch conduit 2" connects the return conduit 2" and the .inlet conduit 23! and has an adjustable damper 2" associated therewith so that the returned air through the conduit 2" may be bypassed around the heater 234 in variable amounts directly into the conduit 2", thus affording a simple temperature control means.

From the above. it will be seen that the strip l2 passes directly into the vertical drying chamber 232 and is trained over the conveyor rolls 22! and 228 and then passes out through opening 22'. The heated air enters the conduit 232 adjacent the bottom thereof and passes upwardly over roll 226 and into the main portion oi the oven.

This heated air is supplemented by the conduit 252 and all of the heated air then passes out of the oven through outlet 2".

- with this construction it will be evident that thehot gases envelop the stripas it first enters the oven so that the rust-proofing solution will be dried before it reaches the conveyor roll 22!.

This has the advantage pointed out above in detail.

The strip I2, after leaving the oven, is coiled on a suitable spool I22. The spool I22 is driven by suitable means such as a motor 280 connected to the spool I22 by suitable drive means 2l2. The spool I22, in the embodiment illustratedyis the only driven roller, the remaining rollers about I of wide width, there is not sufficient time between the time the strip leaves the oven until it reaches the spool I22 to cool down suillciently so that it will not be injured during the coiling operation. To take care of such a contingency, suitable cooling means are disposed adjacent the coil and blow a cooling medium, such as air, against the strip so as to reduce its temperature to a proper coiling temperature. Such cooling means may also be in the form of a water or liquid spray disposed at any suitable point between the oven and the spool. One example is illustrated in the form of transversely extending tubular conduits 210, disposed on opposite sides of the strip and having apertures therein directed preferably in a direction opposite to that of the direction of movement of the strip. tubular members 210 may be connected to a suitable blower (not shown), so that air is directed against the strip. A plurality of such means mayv has -been set to operate continuously on strip steel as wide. as twenty inches and up to .050 gauge. In this particular apparatus, the-strip is run at approximately fifteen feet-per minute. Also, in this apparatus the strip is in the scrubber approximately three minutes, .in the pretreatment solution approximately thirty seconds.

Such

in the wash tank and. spray approximately thirty seconds, and in the final coating solution approx-- imately thirty seconds. The strip then passes through the oven in approximately two minutes, the oven temperature being between 600' and 650" F., so th is at appro tely 550 F. The immersion coating and baking times which we have given for our pilot installation have been found to be entirely satisfactory for the gauge and width strip which is being used.

The above-mentioned operation is merely exemplary, and it will be appreciated by those skilled in the art that wider strip steel of heavier gauges may be used and that the times, speeds, and temperatures may be varied within the scope of the present invention. .The strip may be carried through the apparatus at a much faster rate and the tanks and other processing devices may be sized proportionately to give the desired treatment times.

It will be evident that by the various embodiments of the invention described above, simple and efllcient means for rust-proofing strip steel is provided in which the surfaces oi the strip may be rapidly and effectively treated. Also, the

structures or the present invention afford means by which strips of varied gauge and width may be eflectively treated.

Formal changes may be made in the specific embodiments of the invention described without departing from the spirit and substance of the invention, the scope 01'. which is commensurate with the appended claims.

What is claimed is:

1. An apparatusfor treating metal strip comprising a series of tanks containing treating fluids, means for conducting a strip in sequence into said tanks. a baking oven, means ior'conducting said strip through said baking oven and pulling means for acting upon the strip upon its emergence from said baking oven, said oven being arranged above the last tank of said series and said conducting means being so disposed therein that the strip passes from the last tank of said series into said oven in a vertical path, and traverses substantially the height of said oven before contacting said conducting means and is then generally led in a reverse direction to its path through said treating tanks and said pulling means being disposed in the vicinity oi the entrance of the strip into the first tank of said series.

2. Apparatus for rust-proofing strip steel comprising a container adapted to contain a rustprooflng solution, an oven disposed above said container, said oven having a downwardly presented inlet opening therein, means for conveying a strip of steel through said container and through said inlet opening into said oven, said last named meanslncluding a roller element disposed within said oven adjacent the top thereof, said roller element being so arranged that said strip is drawn upwardly through said inlet opening and being arranged in a position remote from said inlet opening, means within said oven adjacent said inlet opening forming a drying chamber, heating means associated with said oven, and means conducting thehea-ted gases from said heating means to said oven and introducing such gases into said chamber.

3. Apparatus for rust-proofing strip steel comprising a container adapted to contain a rustprooilng solution, an oven disposed above said container, said oven having a downwardly prethe strip as it leaves the oven sented inlet opening therein, means for conveying a strip of steel through said container and through said inlet opening into said oven, said last named means including a roller element disposed within said oven adjacent the top thereof, said roller element being so arranged that said strip is drawn upwardly through said inlet opening and being arranged in a position remote from said inlet opening, means within said oven adjacent said inlet opening forming a drying chamber, heating means associated with said oven, and means conducting the heated gases from said heating means to said oven and introducing such gases into said chamber, said last named means entering said chamber adjacent the lower end thereof so that said gases pass upwardly through said chamber in enveloping reiationship to said strip.

4. Apparatus for rust-proofing strip steel comprising a plurality of in line containers adapted to contain treating solutions, a drying oven disposed adjacent the last of said containers, means supplying a heating medium to said oven, and conveying means so constructed and arranged as to convey a strip of steel through said containers and through said oven, said conveyor means including a coiling element about which said strip of steel is coiled, said element being disposed at the outlet end of said oven, said coiling element being remotely disposed mpm the outlet so that said strip will cool down before reaching said element, and cooling means disposed adjacent said element for cooling said strip- 7 ROBERT H. GORDON. ROY P. TOOKE.

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