US2759850A

US2759850A - Coating sheets with molten metal and apparatus therefor

Info

Publication number: US2759850A
Application number: US322202A
Authority: US
Inventors: Edward J Knopf
Original assignee: Wheeling Steel Corp
Current assignee: Wheeling Steel Corp
Priority date: 1952-11-24
Filing date: 1952-11-24
Publication date: 1956-08-21
Anticipated expiration: 1973-08-21

Description

-Aug. 21, 1956 E. J. KNOPF 2,759,850

COATING SHEETS WITH MOLTEN METAL AND APPARATUS THEREFOR Filed Nov. 24. 1952 2 Sheets-Sheet l 9 M JJJ JJJJ J) J J JJ JJ JJJJJ J M F 2 y l2 u IINI/ENTOR. EDWARD J. KNOPF MWJWQ HIS ATTORNEYS Aug. 21, 1956 E. J. KNOPF 2,759,850

COATING SHEETS MOLTEN MET-AL AND APPARATUS THEREFOR Filed Nov. 24, 1952 2 Sheet-Sheet 2 d d i INVENTOR. EDWARD J. KNOPF W fi hd 31% HIS ATTORNEYS United States Patent '0 COATING SHEETS WITH MOLTEN METAL AND I APPARATUS THEREFOR Edward J. Knopf, St. Clairsville, Ohio, assignor to Wheelmg Steel Corporation, Wheeling, W. Va., a corporation of Delaware 7 Application November 24, 1952, Serial No. 322,202

20 Claims. (Cl. 11 7114) new anduseful results are obtained.

My invention is applicable generally to the coating of sheets with molten metal, examples of which are hot dip galvanizing, terne coating and tin coating. For purposes of explanation and illustration I shall describe the application of my invention in the hot dip galvanizing of steel sheets by immersing the sheets in a bath of molten spelter and delivering the sheets successively edgewise upwardly out of the bath. Galvanizing apparatus which comprises means for advancing sheets successively along a path into and through a bath of molten spelter in a so-called galvanizing pot and delivering the sheets upwardly out of the bath by pinch rolls which are partially submerged in the bath isold and very well known to those skilled in the art. Great difiiculty'has been encountered because of non-uniformity of the coating, especially in respect of thickness. In galvanizing apparatus as heretofore employed and as employed to this day in all plants not utilizing my invention an undesirably great quantity ofspelter lies in the socalled nip of the rolls, i. e., the space between the rollsimmediately above their line of tangency, between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath, that spelter cooling somewhat by reason of being largely segregated from the remaining spelter in the pot and being in contact with the atmosphere. The result is that the coatings applied to the sheets are not uniform, each sheet having a relatively heavy or thick coating at its leading edge where the relatively cool metal in the nip of the rolls has a greater tendency to deposit on or cling to the sheet than the hotter metal below the rolls. Also, as is well known to those skilled in the art, there is a tendency for the metal in the nip of the rolls to flow toward the ends of the rolls so that the coating applied to the sheet is also relatively heavy adjacent the side edges of the sheets. These problems have existed unsolved prior to my invention although many efforts to solve them have been made. Galvanizing rolls have been grooved in various ways in an effort to solve the problem and numerous patents on grooved galvanizing rolls as well as grooved rolls for coating sheets with other molten metals have been granted. However, the mere grooving of the rolls does not solve the problem.

I have discovered how to obviate both the relatively thick coating at the leading edges of the sheets and the relatively thick coating adjacent the side edges of the sheets. I substantially inhibit exposure of molten metal of the bath at the surface of the bath Where the sheets 2,759,850 PatentedAug. 21, 1956 are. delivered out of the bath between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath and also permit substantial exposure of molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath during the time while a sheet is passing out of the bath whereby I form on the sheet a coating of substantially uniform thickness along the sheet in the direction of delivery. I preferably also substantially inhibit flow generally parallel to the surface of the bath generally in the plane of sheets being delivered out of the bath of such small amount of molten metal of the bath as may become exposed at the surface of the bath where the sheets are'delivered out of the bath between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath whereby I form on the sheet a coating of substantially uniform thickness not only along the sheet inthe direction of delivery but also across the sheet transversely of the direction of delivery.

I preferably deliver the sheets successively edgevvise upwardly out of the bath by cooperating rolls engaging the sheets at the respective faces thereof while substantially inhibiting exposure of molten metal of the bath at the surface of the bath between the rolls between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath and also permitting substantial exposure of molten metal of the bath at the surface of the bath between the rolls during the time while a sheet is passing out of the bath. I prefer ably by the rolls substantially inhibit flow generally parallel to the surface of the bath generally in the plane of sheets being delivered out of the bath of such small amount of molten metal of the bath as may become exposed at the surface of the bath between the rolls between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath.

The rolls preferably each have circumferentially extending raised and depressed portions arranged alternately longitudinally of the roll with the raised portions of one roll opposite the depressed portions of the other roll and vice versa.- I move the rolls toward each other when no sheet is disposed between them so that the raised and depressed portions of the respective rolls interfit. Such interfitting substantially inhibits exposure of molten metal of the bath at the surface of the bath between the rolls between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath. The interfitting portions of the rolls also substantially inhibit flow generally parallel tothe surface of the bath generally in the plane of sheets being delivered out of the bath of such small amount of molten metal of the bath as may become exposed at the surface of the bath between the rolls between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath. Substantial exposure of molten metal of the bath at the surfaceof the bath between the rolls is permitted through the depressed portions of the rolls during the time while a sheet is passing out of the bath. Thereby I form on the sheet a coating of substantially uniform thickness along the sheet in the direction of delivery and also across the sheet transversely of the direction of delivery.

99.1 d ven. t rmtelrs tedsh etsu ward y. working face of each roll consisting of axially spaced gerierally circumferentially extending projections each of which has an axial dimension less than the axial dimension of the space between projections. The projections may be separate ring-shaped projectionsor they may form continuations of one another to constitute in effect a single continuous projection having generally the form of a screw thread. The word projectionsfas used in the plural comprehends out only separate ring-shaped projections but also the successive portions along the roll of a continuous projection having generally the form of a screw thread. i

The projections of the respective rolls are preferably staggered so that the sheets are delivered by engagement therewith of non-opposed projections. Each projection preferably has surface portions outwardly inclined toward each other.

The working face of each roll may consist of alternate substantially cylindrical portions and pointed depressions extending generally circumferentially of the roll. Preferably the substantially cylindrical portions of each roll are opposed to the depressions of the other roll. The working face of each roll may consist of alternate substantially V-shaped grooves and ridges and desirably the sides of the grooves coincide with the sides of the ridges, the grooves of each roll preferably being opposed to the ridges of the other roll.

I further provide, in mechanism for delivering metalcoated sheets from a bath of molten coating metal which comprises two rolls, means for rotatably mounting the rolls in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal, means for relatively urging the mounting means for the respective rolls toward each other so that the rolls press against each other or against sheets disposed between them and means for rotating the rolls to deliver metal-coated sheets upwardly between them, the working faces of the rolls being shaped to interfit when no sheets are disposed between them. The working face of each roll may consist of axially spaced generally circumferentially extending projections, the projections of the respective rolls being staggered so that the rolls interfit when no sheets are disposed between them. The projections may have sides which in the radially outward direction are inclined toward each other, the sides of the projections of the respective rolls contacting one another when the rolls interfit. Opposed sides of adjacent projections preferably meet to form generally V-sh'aped grooves between the projections and when no sheets are disposed between them the rolls preferably interfit with each projection of one roll in a groove of the other roll. Preferably the projections have crests shaped to afford engagement of sheets throughout a substantial area when sheets are disposed between the rolls.

Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof and a present preferred method of practicing the same proceeds.

In the accompanying drawings I have shown a present preferred embodiment of the invention and have illustrated a present preferred method of practicing the same in which 7 Figure l is a fragmentary diagrammatic vertical crosssectional view through hot dip galvanizing apparatus utilizing my invention showing a sheet being delivered;

Figure 2 is a fragmentary plan view to enlarged scale of the galvanizing rolls shown in Figure 1 showing the relative position of the rolls with a sheet disposed therebetween and being delivered out of the bath of molten spelter thereby;

Figure 3 is a view similar to Figure 1 showing the relative position of the rolls when no sheet is disposed between them; and

Figure 4 is a view similar to Figure 2 of the rolls in the relative position which they occupy in Figure 3.

Referring now more particularly to the drawings, there is "straws purely diagrammatically a galvanizing pot designated generally by reference numeral 2 and which may be conventional. Disposed within the pot is a body of molten spelter 3. The spelter is maintained in molten condition by means not constituting the present invention and hence not shown. Two rolls 4 are rotatably mounted in position partially submerged in the bath of molten spelter in opposed relationship with the axes of the rolls substantially parallel and horizontal, the rolls being arranged to be driven through their necks in there'spective directions indicated by the arrows in Figures 1 and 3 to deliver metal-coated sheets upwardly out of the spelter bath. The driving means for the rolls may be conventional. Each roll is mounted in bearings carried by a support 5. The roll supports and bearings may likewise be conventional. The left-hand support 5 viewing each of Figures 1 and 3 may be stationarily mounted. The right-hand support 5 viewing each of Figures 1 and 3 may be carried by lever means 6 pivoted at 7 and biased to relatively press the rolls together at all times by -spring means 8. All of the structure thus far described except the structure of the rolls themselves which is presently to be described may be conventional; in other words, my novel rolls may be used to replace existing rolls in a conventional or standard galvanizing pot without making any other changes, the replacement of the rolls bringing about the advantages of my invention.

Each of the rolls 4 has a neck 9 at each end and a body ltl between the necks. The roll bodies 10 are formed in a novel manner. In the form shown in the drawings each roll body 10 has a working face consisting of axially spaced generally circumferentially extending projections 11 each of which has an axial dimension less than the axial dimension of the space between p'rojections. The projections of the respective rolls are staggered so that as clearly shown in Figure 2 the sheets are delivered by engagement therewith of non-opposed projections 11. Each projection 11 has surface portions 12 which are outwardly inclined toward each other. Otherwise stated, the working face of each roll consists of alternate substantially cylindrical portions 11 and pointed depressions extending generally circumferentially of, the roll; Each depression is formed by opposed sides of adjacent projections which in the structure shown meet to form generally V-shaped grooves between the projections. Each groove is designated 13.

When a sheet 14 is being delivered upwardly out of the spelter bath by the rolls 4 as indicated by the arrow in Figure l the rolls are by the sheet maintained against interfitting despite the action of the spring means 8 as shown in Figures 1 and 2. However, substantial exposure of molten spelter at the surface of the bath is permitted through the grooves 13. After each sheet has been delivered upwardly by the rolls 4 the spring means 8 moves the right-hand roll viewing each of Figures 1 and 3 toward the left relatively to the left-hand roll so that the rolls interfit as shown in Figures 3 and 4. The surface portions 12 or sides of the projections of the respective rolls contact one another as shown in Figure 4. When the rolls are in interfitting position they substantially inhibit exposure of molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath. With rolls having fiat-crested projections as shown in the drawings there are minute triangle-shaped openings 15 between the bottoms of the grooves and the crests of the projections. The area of the openings 15 may be determined by the roll design. They may be made larger or smaller as desired. They may be eliminated entirely by forming the projections with pointed instead of flat crests or by making the grooves with flat bottoms to conform to the hat crests. In any event, the interfitting of the rolls as shown in Figure 4 substantially inhibits exposure of molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes-out of the bath.

Moreover, as above stated, the rolls permit substantial exposure of molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath during the time while a sheet is passing out of the bath, such exposure being through the grooves 13 asclearly shown in Figure 2. Moreover, the interfitting rolls substantially inhibit flow generally parallel to the surface of the bath generally in the plane of sheets being delivered out of the bath of such small amount of molten metal of the bath as may become exposed at the surface of the bath where the sheets are delivered out of the bath be tween the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath. The inhibition of flow along the rolls is due to the fact that the interfitting roll projections form in effect a dam or series of dams having substantially vertical extent so that the molten metal in the triangle-shaped openings 15 has no opportunity for axial displacement. This will be true so long as the level of the spelter in the pot does not rise substantially above a horizontal plane containing the axes of the rolls, although it may rise slightly above that plane while still being confined against axial flow.

The normal level of the spelter in the pot is at approximately the horizontal plane defined by the axe-s of the rolls. The surface of the molten spelter in the pot, except between the rolls, is covered with a layer of flux 16 which is of relatively low specific gravity and floats upon the surface of the molten spelter.

While my invention is applicable to the application to sheets of metallic coatings of various thicknesses I have found in actual practice that my rolls are especially well adapted for coating steel sheets with a relatively heavy galvanized coating of spelter, as, for example, a coating such as is used on sheets for making culvert pipe.

l shall describe the coating of a sheet by the use of my novel rolls. Before the leading edge of the sheet enters the nip of the rolls there is very little spelter in the nip of the rolls. The amount of spelter in the nip of the rolls is determined by the roll design, i. e., by the areas of the openings 15. Such spelter as is in the nip of the rolls is maintained against movement axially of the rolls, insuring against a coating of uneven thickness transversely of the sheet. For the application of heavy or relatively thick coatings the presence of some spelter in the nip of the rolls in advance of the passing of the leading edge of the sheet into the nip of the rolls may be desirable. it is to be borne in mind that as soon as the leading edge of the sheet enters the nip of the rolls the rolls are spread apart from the relation shown in Figure 4 to the relation shown in Figure 2 and virtually instantaneously molten speiter is permitted to pass up through the grooves 13. Again the quantity of molten spelter which is permitted to pass up through the grooves 13 is determined by the design of the rolls. The small amount of spelter which passed up through the triangle-shaped openings 15 before the leading edge of the sheet reached the nip of the rolls serves to insure deposition of the desirably thick coating on the sheet commencing at the leading edge thereof. The spelter passing up through the grooves 13 after the sheet has entered the nip of the rolls insures continuous application of the desirably thick coating. Thus I effect close control of the quantity of spelter available at the nip of the rolls for application to the sheets both at the very beginning of the coating of a sheet and thereafter throughout the entire time during which the sheet is being coated. At the same time I control the spelter so as to obviate flow of spelter in the nip of the rolls axially of the rolls prior to the time when the leading edge of the sheet enters the rolls thus insuring against a coating of uneven thickness transversely of the sheet.

While I have shown and described a present preferred embodiment of 'the invention and a present preferred method of practicing the same it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and scope of the following claims.

I claim:

practiced within the 1. In the coating of sheets with molten metal by im'- mersing the sheets in a bath of molten metal and delivering the sheets successively edgewise upwardly out of the' bath, substantially entirely inhibiting exposure of molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath between the time when the trailing edge of one sheet passe-s out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath and also exposing molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath during the time while a sheet is passing out of the bath whereby to form on the sheet a coating of substantially uniform thickness along" the sheet in the direction of delivery.

2. In the coating of sheets with molten metal by immersing the sheets in a bath of molten metal and dc livering the sheets successively edgewise upwardly out of the bath, substantially entirely inhibiting exposure of molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath, substantially inhibiting flow generally parallel to the surface of the bath generally in the plane of sheets being delivered out of the bath of such small amount of molten metal of the bath as may become exposed at the surface of the bath where the sheets are delivered out of the bath between thetime when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath and also exposing molten metal of the bath at the surface of the bath where the sheets are delivered out of the bath during the time while a sheet is passing out of the bath whereby to form on the sheet a coating of substantially uniform thickness along the sheet in the direction of delivery and also across the sheet transversely of the direction of delivery.

3. In the coating of sheets with molten metal by immersing the sheets in a bath of molten metal and de-' livering the sheets successively edgewise upwardly out of the bath by cooperating rolls engaging the sheets at the respective faces thereof, substantially entirely inhibiting exposure of molten metal of the bath at the surface of the bath between the rolls between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the suc ceeding sheet passes out of the bath and also exposing molten metal of the bath at the surface of the bath between the rolls during the time While a sheet is passing out of the bath whereby to form on the sheet a coating of substantially uniform thickness along the sheet in the bath and the time when the leading edge of the succeding sheet passes out of the bath, by the rolls substantially inhibiting flow generally parallel to the surface of the bath generally in the plane of sheets being delivered out of the bath of such small amount of molten metal of the bath as may become exposed at the surface of the bath between the rolls between the time when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath and also exposing molten metal of the bath at the surface of the bath between the rolls during the 7 time, while. a. sheet; is-passing out of the bath whereby to'form on the. sheet acoating of substantially uniform' thickness along the sheet in the direction of delivery and also across the sheet transversely of the directionof deliverya 5. In the coating. of sheets of molten metal by immersing the sheets in a bath-of molten metal and delivering the sheets successively edgewise upwardly out of the bath by cooperating 'rolls engagingithe sheets at the respective faces thereof and each having.circumferentially extending raised and'depressed portions arranged alternately longitudinally of the roll with the raised portions of one roll opposite the depressed portions of the other roll and vice'versa', substantially inhibiting exposure of molten metal'of'the bath at the surface of the bath between therolls between thetime. when the trailing edge of one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath by movingthe rollstoward each other so that the raised and-deprcssed portions of tie respective rolls interfit and also permitting through'rthc depressed portions of the respective rolls substantial exposure of molten metal of the bath at-thesurface of the bath between the rolls duringthe timewhile a sheet is passingoutof the bath whereby to form on the sheet a coating of substantially uniform thickness along the sheet in the direction of delivery.

6. In the coating of sheets of molten metal by immersing the sheets in a bath of molten. metal and delivering the sheets successively edgewise upwardly out of the bath by cooperating rolls engaging the sheets at the respective faces thereof and each having circumferentially extending raised and depressed portions arranged alternately longitudinally of the roll with the raised portions of one roll opposite the depressed portions of the other roll and vice versa, substantially inhibiting exposure of molten metal of the bath at the surface of the bath between the rolls between the time when the trailing edgeof one sheet passes out of the bath and the time when the leading edge of the succeeding sheet passes out of the bath by, moving'the rolls toward each other so that the raised and depressed portions of the respective rolls interfit, by the interfitting portions of the rolls substantially inhibiting flow generally parallel to the surface of the bath generally in the plane of sheets being delivered out of the bath of such small amount of molten metal of the bath as may become exposed at the surface of the bath between the rolls between the time when the trailing edge of one sheet passes out of the bath and the. time when theleading edge of the succeeding sheet passes out of the bath and also permitting through the depressed portions of the respective rolls substantial exposure-of molten metal of the bath at the surface of the bath between the rolls during the time while a sheet is passing out'of the bath whereby to form on the sheet a coating of substantially uniform thickness along the sheet in the direction of delivery and also across the sheet transversely of the direction of delivery.

7. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adaptedto be rotatably mounted in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to delivermetal-coated sheets upwardly, the working face of each roll consisting of axially spaced generally circumferentially extending projections each of which has an axial dimension less than the axial dimension of the space between projections, the projections of the respective rolls being so positioned as to permit penetrationof one roll into the other.

8. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position partially submerged in' the bath" in opposed relationship with the axes of the rolls substantially parallel and horizontal and'to be driven" to deliver. metal-coated sheets upwardly, the working face ofea'ehiroll consisting'of axially spaced generally circumferentially extending projections, the projections of the respective rolls being'staggered so that the sheets are delivered" by engagement therewith of non-opposed projectrons.

9. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to deliver metal-coated sheets upwardly, the working face of each roll consisting of axially spaced generally circumferentially extending projections each of which has opposed surface portions outwardly inclined toward each other, the projections of the respective rolls being so p0- sitioned as to permit penetration of one roll into the other.

10. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to deliver metal-coated sheets upwardly, the working face of each roll consisting of axially spaced generally circumferentially extending projections each of which has surface portions outwardly inclined toward each other, the projections of the respective rolls being staggered so that the sheets are delivered by engagement therewith of nonopposed projections.

11. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to deliver metal-coated sheets upwardly, the working face of each roll consisting of alternate substantially cylindrical portions and pointed depressions extending generally circumferentially of the roll, said portions and depressions of the respective rolls being so positioned as to permit penetration of one roll into the other.

12. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to deliver metal-coated sheets upwardly, the working face of each roll consisting of alternate substantially cylindrical portions and pointed depressions extending generally circumferentially of the roll, the substantially cylindrical portions of each roll being opposed to the depressions of the other roll.

13. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position pantially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to deliver metal-coated sheets upwardly, the working face of each roll consisting of alternate substantially V-shaped grooves and ridges, said grooves and ridges of the respective rolls being so positioned as to permit penetration of one'roll into the other.

14.- Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to deliver metal-coated sheets upwardly, the working face of each roll consisting of alternate substantially V-shaped grooves and ridges with the sides of the grooves coinciding with the sides'of the ridges, said grooves and ridges of the respective rolls being so positioned as to permit penetration of one roll into the other.

l5. Means for delivering metal-coated sheets from a bath of molten coating metal comprising two rolls adapted to be rotatably mounted in position pantially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal and to be driven to deliver metal-coated sheets upwardly, the working face of each roll consisting of alternate substantially V-shaped grooves and ridges, the grooves of each roll being opposed to the ridges of the other roll.

16. In mechanism for delivering metal-coated sheets from a bath of molten coating metal which comprises two rolls, means for rotatably mounting the rolls in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal, means for relatively urging the mounting means for the respective rolls toward each other so that the rolls press against each other or against sheets disposed between them and means for rotating the rolls to deliver metal-coated sheets upwardly between them, the working faces of the rolls being shaped to penetrate each other and fit together when no sheets are disposed between them.

17. In mechanism for delivering metal-coated sheets from a bath of molten coating metal which comprises two rolls, means for rotatably mounting the rolls in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal, means for relatively urging the mounting means for the respective rolls toward each other so that the rolls press against each other or against sheets disposed between them and means for rotating the rolls to deliver metalcoated sheets upwardly between them, the working face of each roll consisting of axially spaced generally circumferentially extending projections, the projections of the respective rolls being staggered so that the rolls interfit when no sheets are disposed between them.

18. In mechanism for delivering metal-coated sheets from a bath of molten coating metal which comprises two rolls, means for rotatably mounting the rolls in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal, means for relatively urging the mounting means for the respective rolls toward each other so that the rolls press against each other or against sheets disposed between them and means for rotating the rolls to deliver metal-coated sheets upwardly between them, the working face of each roll consisting of axially spaced generally circumferentially extending projections having sides which in the radially outward direction are inclined toward each other, the projections of the respective rolls being staggered so that when no sheets are disposed between them the rolls interfit with the sides of the projections of the respective rolls contacting one another.

19. In mechanism for delivering metal-coated sheets from a bath of molten coating metal which comprises two rolls, means for rotatably mounting the rolls in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal, means for relatively urging the mounting means for the respective rolls toward each other so that the rolls press against each other or against sheets disposed between them and means for rotating the rolls to deliver metal-coated sheets upwardly between them, the working face of each roll consisting of axially spaced generally circumferentially extending projections having sides which in the radially outward direction are inclined toward each other, opposed sides of adjacent projections meeting to form generally V-shaped grooves between the projections, the projections of the respective rolls being staggered so that when no sheets are disposed between them the rolls interfit with each projection of one roll in a groove of the other roll and with the sides of the pro jections of the respective rolls contacting one another.

20. In mechanism for delivering metal-coated sheets from a bath of molten coating metal which comprises two rolls, means for rotatably mounting the rolls in position partially submerged in the bath in opposed relationship with the axes of the rolls substantially parallel and horizontal, means for relatively urging the mounting means for the respective rolls toward each other so that the rolls press against each other or against sheets disposed between them and means for rotating the rolls to deliver metal-coated sheets upwardly between them, the working face of each roll consisting of axially spaced generally circumferentially extending projections having sides which in the radially outward direction are inclined toward each other, the projections having crests shaped to atford engagement of sheets throughout a substantial area when sheets are disposed between the rolls, the projections of the respective rolls being staggered so that when no sheets are disposed between them the rolls interfit.

References Cited in the file of this patent UNITED STATES PATENTS 2,025,768 Nieman Dec. 31, 1935 2,227,976 McLin Jan. 7, 1941 2,236,213 Jenkins et al Mar. 25, 1941 2,309,585 Haddock Jan. 26, 1943 2,345,058 Matteson Mar. 28, 1944 2,577,904 McNabb et al. Dec. 11, 1951

Claims

1. IN THE COATING OF SHEETS WITH MOLTEN METAL BY IMMERSING THE SHEETS IN A BATH OF MOLTEN METAL AND DELIVERING THE SHEETS SUCCESIVELY EDGEWISE UPWARDLY OUT OF THE BATH, SUBSTANTIALLY ENTIRELY INHIBITING EXPOSURE OF MOLTEN METAL OF THE BATH AT THE SURFACE OF THE BATH WHERE THE SHEETS ARE DELIVERED OUT OF THE PATH BETWEEN THE TIME WHEN THE TRAILING EDGE OF ONE SHEET PASSES OUT OF THE BATH AND THE TIME WHEN THE LEADING EDGES OF THE SUCCEEDING SHEET PASSES OUT OF THE BATH AND ALSO EXPOSING MOLTEN METAL OF THE BATH AT THE SURFACE OF THE BATH WHERE THE SHEETS ARE DELIVERED OUT OF THE BATH DURING THE TIME WHILE A SHEET IS PASSING OUT OF THE BATH WHEREBY TO FORM ON THE SHEET A COATING OF SUBSTANTIALLY UNIFORM THICKNESS ALONG THE SHEET IN THE DIRECTION OF DELIVERY.