US 2281340 A
Description (OCR text may contain errors)
April w. F. THIELE ETAL PAPER COATING- DEVICE a Sheet s-Shet 1 Filed Sept. 8, 1939 Thzele I rzzey:
. v Q a C h 0 M.
MR \w APril 4 w. F. THIELE ETAL 2,281,340
- PAPER coATIim DEVVICE Filed Sept. 8, 1939 s Sheets-Shet 2 April 28, 1942. w. F. THIELE ETAL 2, 8 ,3
PAPER COATING DEVICE Filed Sept. 8, 1939 s Sheets-Sheet s I Patented A r. 28, 1942 2,281,340 PAPER COATING DEVICE William F. Thiele and Howard B. Richmond, Wisconsin Rapids, Wis., assignors to Consolidated Water Power and Paper Company, Wisconsin Rapids, Wis., a corporation of Wisconsin Application September 8, 1939, Serial No. 293,982 3 Claims. ((21. 91- 55) This is a continuation-in-part of our co-pend-.
ing application for United States Letters Patent,
Serial No. 181,665, filed December 24, 1937, and
entitled Paper coating device.
This invention relates to improvements in coating devices, and refers specifically to a device for coating paper, paperboard, fabric or other web-like material by means of rolls while the web-like material is passing around a drum drier.
The present invention is applicable to the coating of light-weight papers to render the same opaque; coating wall paper, relatively heavy paperboard, and is particularly adaptable for coating so called newsprint paper to produce a fine printing surface thereon.
The objects and advantages of my-invention will be apparent from the accompanying drawings and following detailed description.
In the drawings, I V
Fig. 1 is a diagrammatic side elevational view of my coating system.
Fig. la is a diagrammatic view illustrating a modified arrangement for tensioning the webprior to coating.
Fig. lb is a similar view illustrating a similar relationship as applied to the mechanism for coating the opposite side of the web.
Fig. 2 is a fragmentary side elevational view of the coating unit illustrating the distributing rolls in separated relationship.
by calendering the web while it has a prede termined moisture content.
To secure the desired moisture content cold I water may be circulated through drum 2 and, if desired, cold water may be circulated through roll 4. When these members are so cooled, a film of moisture willcollect upon their surfaces due tothe condensation of the moist air which usually surrounds this portion of the machine. This moisture is imparted by the roll 4 and/or drum 2 to the web. If the web 3 is exceptionally moist going to calender 5, steam heated rolls in Fig. 3 is a fragmentary side elevational view of the coating unit for the opposite side of the paper.
Fig. 4 is a view illustrating the coating unit shown in Fig. 2 with the distributing rolls in operative position.
Referring in detail tothe drawings, I and 2' super-calender stack 5. The paper upon passing through the calender stack 5 is given a primary calendering before it is coated, which is an important step in securing a high finished 1 paper or-board. If a high finish is not desired, the calender-5 may be eliminated. If a high or smooth finish is desired the web 3 when it passes through the stack 5 is free from small hills and valleys and craters, which result is accomplished i ustrated, but
the calender may be used. A
' After leaving calender 5, web 3 is carried over guide roll 6 and thence passed into contact with the surface of the heated drying drum 1. A bank of rolls 8 are positioned adjacent drum 1, said bank comprising rolls 9, in, il, l2 and [3 which latter roll is in contact with orclosely adjacent web 3 carried upon drum I. The bank of rolls 8 comprises a coating device and will be hereinafter-described in greater detail.
The roll l3 imparts a pre-worked film of coating material to one surface of web 3 while the same is, on .the drum 1. A plurality of nozzles I 4 are disposed adjacent the path of travel of the web 3 during its passage on drum 1 and are adapted to discharge hot or cold air into contact with the coating recently applied to the web surface to set the coating sufliciently to prevent it being marred by subsequent operations.
It is highly desirable that the web 3 whentrained around roll I be free of wrinkles, folds or other irregularities. Consequently, it must be carried around roll 1 with a relatively high degree of tension so that it conforms minutely with the surface of. the drum. In addition, roll l3 may be driven at a slightly greater peripheral speed than that of the drum 1 and web 3, and
hence there is a tendency to move the web rela-- tive to the surface of the drum 1, that is, to crinkle the web. Therefore, it usually is desirable to pass the web 3' Fig. 10 between two contacting, driven rolls -4' and 5' prior to the passage of the web around the drum 1', the
function of which rolls isto maintain aconstant condition of tension, (depending upon the speed at which said rolls are driven) in the web between themselves andthe drum 1' irrespective of the tension of the web as it leaves the calender 5. The two contacting drivenrolls w take the place of the-conventional roll 6 when the two rolls are used, the web will travel substantially vertical from said rolls to the nip between drum 1' and roll l3. It will'readily be seen that an arrangement of this type will compensate for any differences in speed between the sections of the machine ahead of, and behind the drum 1'.
Web 3 after leaving drum 1 is passed around a heated drier drum |5 with its coated surface on contact with the drum surface. However, the preliminary set given the coating by the air from the nozzles 14 permits this contact without detrimental effect to the coating. After leav ing drum I5, web 2 is carried into contact with drums I6, l1, l8 and IS, the web being confined, while in contact with drums l8, l8 and H! by blanket or felt 20 which is guided by suitable rollers 2|. Upon passing over the above mentioned drums the coating is completely dried since all of said drums are heated and tend to drive off the moisture content of the coating material. 1
Two distinct advantages accure from the use of my invention, one, by applying a coating film which has previously been smoothed and reduced to a film of uniform thickness requiring no scraping or brushing while on the web, a coating material may be used which has a relatively high solids content and, hence, a low moisture content, and secondly, by applying this film with an already reduced moisture content to the web while it is traveling on the heated surface of drum 1, a rapid initial setting of the coating takes place permitting subsequent operations to be performed in a short period of time. This latter coupled with the provision of the nozzles |4 permit of using, my invention at high web speeds without danger of damage to the coated surface. r
If paperboard is to'.be coated, the surface of said board being more absorbent than the usual paper will tend to quickly absorb the liquid carrier of the coating material, and therefore the heated drum alone without the air driers mav be sufficient to properly set the coating film.
After leaving drum 9, web 3 is carried around heated drum 22 with the coated side of said web in contact with the drum surface. A bank of rolls 23 is disposed adjacent drum 23 comprising rolls 24, 25, 26 and 21, the last mentioned roll being in contact with, or closely adjacent web 3 upon drum 22. The bank 23 comprising a coating unit for coating the reverse side of web 3, and will be hereinafter more fully described. A
plurality of nozzles 28 are positioned around drum 22, and, similar to nozzles M, are adapted to direct hot or cold air into contact with the freshly coated surface to preliminarily set the coating.
The web, after leaving drum l9, Fig. 1b, may be passed between a pair of driven tensioning rolls 20' and 2 l similar to the arrangement hereinbefore described with respect to drum 1', said tensioning rolls functioning for the same purpose, that is, to tension the web during its passage between rolls 22 and 21', corresponding to rolls 22 and 21. In addition, if paperboard is to be coated, the blowers 28 may be eliminated, if desired.
After leaving drum 22, the web is carried nip of a super-calender stack 31 wherein the web is calendered to a fine finish. Thereafter the web may be reeled, cut into sheets or treated otherwise.
If it is desired to coat only one side of the web 3, the bank 8 or 23 may be rendered inoperative, as will be hereinafter described, depending on which side of the web is to be coated.
The coating unit 8 is illustrated in Figs. 2 and 4 in detail, Fig. 2 illustrating the unit in inoperative position, and Fig. 4 illustrating the unit 'in operative position. Referring particularly to Fig. 4, rolls 9 and I0 are respectively mounted upon shafts 38 and 39 which are Journalled in bearings 40 and 4| respectively. Bearing4|i is mounted upon the upper end of standard 42 which, in turn, is pivotally mounted, as at 43, upon member 44. Bearing 4| is mounted on the upper end of standard 45 which, in turn, is pivotally mounted, as at 46, upon support 41. The member 44 which carries standard 42 is rigidly connected to standard 45. It is to be understood, of course, that the rolls 9 and ID are supported at each end thereof and at the opposite end of the rolls, bearings and standards such as described, are also provided.
The rolls 9 and I0 are adapted to be maintained in substantial contact with each other and the nip thus provided is adapted to carry a quantity of coating material which may be introduced through pipe 48 controlled by valve 49. Substantially triangular dams 58 are positioned at each end of thenip between rolls 9 and I0 and are constructed of a material which. when wet, has a very low degree of frictional resistance, for instance, a rubber compound. The dams 50, of course, serve to retain the coating material in the nip. Rolls 9 and ID are impelled toward each other by spring 5| which embrace rod 52. Rod 52 is threadedly anchored in standard 45 and projects through standard 42, spring 5| being confined between standard 42 and an adjusting nut 53 carried at the end of rod 52. It can readily be seen thatmanipulation of the nut 53 controls ,the force urging rolls 9 and I0 toward each other. A screw 54 having a relatively rounded head 55 is threadedly positioned in boss 55 carried by standard 45. The efiective length of screw 54 may be changed by manipulating the screw and the screw may be locked by tightening lock nut 51. Screw 54 extends at substantially right angles to the standard 42 and the head 55 is adapted to make contact with the side of standard 42 to control the minimum distance between the standards. The arrangement is such, therefore, that spring 5| serves to urge rolls 9 and I8 together, and screw 54 serves to limit the proximity of the rolls 9 and ID.
A standard 58 is positioned adjacent standard 45 and is pivotally mounted as at 59 upon support Bl]. The upper end of standard 58 carries bearing 6| in which shaft 62 is journalled, said shaft in turn carrying roll. A boss 63 is carried on the side of standard 58 and an adjusting screw having a relatively rounded head 65 which abuts the side of standard 45. The function of screw 64 is similar to that of screw 54. that is, to control the proximity of rolls I0 and I.
It is to be understood, of course, that the mechanisms herein described are duplicated upon the opposite ends of the rolls, the I-beams 66, 61 and 58 respectively connecting the two onposite standards 42, 45 and 58. A link 68 is pivotally connected as at It to I-beam 88, another link II is pivotally connected as at II to I-beam 61. Links 89 and 'II are threaded at their outer end and are connected by means of the turnbuckle I3 by means of which the effective length of the links 89 and II can be altered. The function of the links 69 and H will be hereinafter more fully described.
A standard It is positioned adjacent standard 58 and is pivotallymounted as at 'I5, upon support I6. nected by means of I-beam 'II. At the upper end of each of the opposite standards a hear- The opposite standards I4 are con-- ing I8 is carried which, in turn, carries shaft with respect to the rolls II and I3. The mechanism for reciprocating said rolls is conventional and. is not believed to need further description.
A boss 83 is carried upon the side of standard It and a screw 84 is threadedly positioned in said boss, said screw carrying a relatively rounded head 85 which is adapted to contact the side of adjacent standard 88. A link 88 is pivotally connected to I-beam I? and. link 81 is pivotally connected to I-beam 68, said links being joined at their ends by turnbuckle 88.
A standard 83 is positioned adjacent standard I8 and is pivotally mounted, as. at 80, upon-support SI. A bearing 92 is carried at the upper end of standard 89 and in turn carries shaft 93 which supports roll I3. The opposite standards 89 are connected by means of I-beam 9t and a link 95 is pivotally mounted upon .said I-beam. Another link 98; is pivotally connected to I-beam TI and said links are joined by means of turnbuckle 91. A boss 98 is carried on the side of standard 89 and a screw 99 is threadedly positioned in said boss, said screw carrying a rela-' tively rounded head I which is adapted to abut the side of standard I6.
It can readily be seen that by means of the screws as, at, at and as the proximity of the rolls 3, III, II, I2 and I3 with respect to each other can be controlled. It can also be seen that by means of the linkages connecting adjacent standards together the maximum degree of separation of rolls III, II, I2 and I3 with respect to each other can also be controlled.
The drier drum ,1 is carried u n shaft IIII which is supported by bearin s I02 positioned at each end of the shaft.. Bearings I82 are mounted upon opposite supports I03 which, in turn, carry extensions I83. A boss I is positioned upon the end of extension I08 and a screw W8 is threadedly' disposed in said boss, said screw having a relatively rounded head I 01 which is adapted to abut the side of the standard 89 and control the degree of proximity between roll I 3 and drum I.
A cylinder I88 is pivotally mounted, as at I08, upon the supporting member I03, said cylinder having a reciprocating rod II II connected to a pistonwhich operates within said cylinder. The end of rod III ispivotally anchored. as at III, to standard 4!. In operation, air under pressure may be introduced into cylinder I88 and tends to move standard 48 toward drum I. This movement, in efl'ect, brings the rounded heads of all of the screws Into contact with the adjacent standards and thereby positions the rolls ll, II, I2 and I3 at a predetermined minimum distance away from each other. is adjustably positioned with respect to drum 1. When air under pressure is introduced into the opposite end of cylinder I08, the piston rod IIII functions to move standard away from drum I.
- When standard 45 is swung about pivot 48, links 89 and II pull standard 58, thereby swinging said standard about pivot 58. This action is, in turn, imparted to standards It and 89. The relative positions of the standards when the rolls are in contact with each other or in film transferring relationship with respect to each other is such that the distance between adjacent standards is less than the aggregate length of the two links connecting adjacent standards. When piston rod IIII acts to separate said rolls, the swinging of the standards tends to lengthen the distances between adjacent standards to the maximum length of the pairs of links between each standard.
When the fact is considered that the drier drum 'I may be between 3 to 12 feet in diameter,
it will be appreciated that the rolls 8, I II, II, I2
and I3 are of relatively large diameter. In addition, although some of said rolls have rubber surfaces, as will be hereinafter more fully described, the bulk of said rolls comprise metal.
The webs which may be coated are frequentlyof 100 inches or even more in width, consequently, a full appreciation of the length of the rolls 9, II), II, I2 and I3 can be had. It can therefore-readily be seen that rolls of such length and weight, supported only'at their ends, will tend to deflect. By disposing the axis of the rolls 9, III, II and I! in a substantially horizontal plane, this deflection will occur at right angles to the lines of osculation between adjacent rolls and, consequently, the clearance between adjacent rolls, or the pressure between adjacent rolls if said rolls are in physical contact, will be uni fonmthroughout the length of the rolls and will be uninfiuenced by such deflection. Accordingly,
I .when coating material is transferred from the gate rolls 9 and III and distributed on the surfaces of rolls II, I2 and I3, a film of relatively uniform thickness will be supplied to the roll I3, which, of course, is the coating roll. In this manner a relatively smooth,'flat film of uniform thickness-will be transferred from the roll I3 to the web 3. Also, in view of the fact that the coating material is smoothed and worked, in its travel from roll to roll, it is possible to use a coating material having a high solids content and, consequently, a low liquid content. Hence, when the coating material is applied to the web 3 by the roll I3, it is in a condition approaching the plastic state.
As has been hereinbefore described, roll ,1 comprises a drier drumand functions not only .as a bed roll against which the roll I3 coats the paper, but also functions to immediately impart a heat to the freshly coated paper which tends to bring about the immediate inception of the setting of the coating material. This, coupled with the provision of the nozzles I8 which surround the drum I, cause a preliminary setting ofthe coating material upon the web which permits said web to be immediately wrapped around the next adjacent drier drum I5 with its coated surface in contact with the surface of said drum without endangering the finish of the coated surface of the web. Hence, there are three features of our invention which all supplemmt each other Likewise roll I3 and which are conducive to the rapid preliminary setting of the coating material, namely, the fact that the coating material is applied to the web in a condition wherein it has a very .suspended as at II5 upon member H6 and'said standard depends downwardly from the pivot point. Of course, shaft H2 is supported at both of its ends by bearings which are carried by opposite standards, the opposite standards being connected by means of I-beam H1.
Roll 25 is carried by shaft H8 which is journalled in bearing H9 carried at the lower end of standard I20. Said standard is pivotally suspended as at I2I upon the supporting member I22 which, in turn, is secured to the overhead structure I23. I-beam I24 connects opposite standards I together and a member H6 is rigidly mounted upon each of the standards I20. A boss I25 is carried upon the side of standard I20 and a screw I26 is threadedly positioned in said boss, said screw having a relatively rounded head I21 which is adapted to abut the side of standard II4 to control the degree of proximity of rolls 24 and 25 with respect to each other. A rod I28 is threadedly positioned in standard I20 and a spring I29 circumscribes said rod adjacent its end, said spring being confined between the side of standard H4 and an adjustof rod I28. By this arrangement standard I I4 is urged toward standards I20 and, consequently, roll I24 is urged towards roll 25.
Roll 26 is mounted upon shaft I 3| which is journalled in bearing I32 carried upon the lower end of standard I33 which is pivotally suspended as at I34 from support I35 which, in turn, is carried by the super-structure I 23. A shaft I36 is journalled immediately above roll 26 and is adapted to carry roll I31 which rests upon the surface of roll 26. Rolls 26 and I31 similar to rolls I2 and 82 oscillate or reciprocate axially in a conventional manner. Opposite supports I33 are connected together by means of I-beam I30. A boss I39 is carried upon the side of standard I33.
having a nalled in bearing I46 carried at the lower end of 7 standard I41 which, in turn, is pivotally suspended as at I48 upon support I49 secured to the super-structure I23. An I-beam I50 connects opposite standards I41 together. A boss I5l is carried upon the side of standard I41 and threadedly receives screw I52 which has a rounded head I53 adapted to abut the side of standard I33 to coning nut I30 threadedly positioned upon the end trol the degree of proximity of rolls 26 and 21. A link I54 is pivotally connected to I-beam I and a link I55 is similarly connected to I-beam I38, said links being joined by turnbuckle I56.
A member I51 is supported from super-structure I23 and carries a boss I58 adjacent its lower end, said boss threadedly receiving screw I59 which has a rounded head I60 adapted to abut the side of standard I41 to control a degree of proximity between roll 21 and drum 22.
Drum 22 is carried by shaft I6I which, in turn, is journalled in bearing I62 carried by the frame member I63. A cylinder I64 is pivotally mounted as' at I65 upon a portion of the frame I63 and a reciprocating piston rod I66 projects from said cylinder, the end of said rod being pivotally secured as at I61 to standard I20. By introducing air under pressure to one end of cylinder I64, the piston rod I66 may be caused to move standard I20 away from drum 22. In so moving, standard H4 also moves in unison with standard I20. Likewise, standards I33 and I41 are pulled away from drum 22 and the rolls 25, 26 and 21 are sepa rated from each other. When air under pressure is introduced into the opposite end of cylinder I14, the piston I66 moves standard I20 towards .drum 22 until standard I20 contacts the end of screw I40 thereby moving standard I33 toward drum 22. This latter standard then contacts the head of screw I52 thereby moving standard I41 into contact with the head I60 of screw I59. It can readily be seen that by the proper manipulation of screws I26, I40, I52 and I59, the degree of proximity of the various rolls with respect to each other and the degree of proximit of roll 21 with respect to the drum 22 canbe controlled.
Rolls 24 and 25 comprise the guide rolls of the unit and the nip between said rolls functions to retain a supply of coating material. The arrangement is substantially similar to that described in conjunction with rolls 9 and I0. The coating material contained with the nip of rolls 24 and 25, during operation of the device is passed from roll 25 to 26 and thence from roll 26 to 21, which latter roll applies the coating material in a smooth, preformed film of uniform thickness to the web 3 travelling over drum 22.
It can readily be seen that all the advantages inherent in the use of the unit 8 hereinbefore described are also existent in the use of the coating unit 23.
As has been hereinbefore described, rolls 9 and I0 and rolls 24 and 25 are the gate rolls or meteringrolls for the coaters 8 and 23 respectively. The passage of coating material from the gate rolls to the remaining rolls of each coating unit is controlled by the screws 54 and I26 respectively and also by driving each pair of gate rolls at speeds varying from the speeds of the distributing rolls. For instance, each pair of gate rolls may be driven by a direct current motor using a conventional fWard-Leonard system of control whereby the gate roll speed may be varied from one revolution per minute to the speed of the distributing rolls.
The remaining rolls II, I2 and I3, and 26 and 21 are positively driven by any conventional drive and are rotated at a peripheral speed equal to the speed of the drums 1 and 22 and, hence, the translatory speed of the web 3.
Rolls 9 and I0 and 24 and 25 are preferably covered with soft rubber. Rolls I3 and 21 are also preferably covered with soft rubber. Rolls I2 and 26 are preferably metal-covered or covered with hard rubber, and roll II is preferably covered with soft rubber. Roll l I, if desired, may be oscillated or reciprocated axially. The rider rolls 82 and I3! are preferably covered with soft rubber and rest by gravity upon rolls l2 and 26 respectively. The rider rolls are driven by frictionfrom rolls l2 and 26. The length of the rubber faces on rolls l3 and 21 is less than the width of the web 3 whereby a ring of coating material will not be built up upon the drums! and 22.
It will be noted that adjacent drum 22 two nozzles 28 designated I68 direct a blast of air onto the web 3 before it enters the nip betweeni roll 21 and drum 22. This is to remove whatever iree moisture which clings to the sheet after leaving drier I 9. 7
As has been hereinbefore described the presat which the web initially contacts the drying drum and after the web has traveled over a minor portion of its total travel over said drum surface to preliminarily heat the web prior to the application of coating thereto, means for depositing a coating material on said roll, said roll being adapted to transfer said coating material to said ,Web, while said web is passing over said drying drum, whereby said coating material carried upon ent invention is applicable to the coating of,
light-weight papers made on a multiple drier paper machine and is also applicable to the coating of wall paper. The fact that the coating mater'ial has a high solids content, between 30 and 60% solids, paper having a high ground wood pulp content such as newsprint can be readily coated.
It is to be understood, of course, that the supercalendar 5 may be supplanted by any conventional device for smoothing the web surface prior to the application of the coating film thereon, such as, a machine calender, a breaker stack or the like. It is also to be understood that when both sides of the web are to be coated that there need be no intervening drying drums. For instance, in Fig. l of the drawings, the second coating unit may be applied to drum I5. If desired, our coating operation may be carried out as a multi-stage process wherein opposite sides of the web are coated a plurality of times while the web is traveling over the driers.
It is 'to be further understood that, although our invention is particularly adaptable for ap-. plying the usual mineral coating to paper or paperboard, other types of coating materials may be-used' such as water resisting materials, acid resisting material, surface sizing materials or. the like. In addition, although coating materials of relatively high solids content can be used, which, of course, is usually of advantage, we are not to be limited tothe use of such coatings since lower 1 solids-content coatings may be employed. Further, the unit illustrated in Fig. 1 may be used separately from the paper making machine, providing, of course, that the web 3 contains the de- ,sired degree of moisture or is suflicientlydry,
By the expression pape as used in the specification and claims is meant paper, paperboardand other web-like materials. By coating ma terial is meant the usual mineral coating suspensions or other liquid or semi-liquid web sur- 7 face influencing agents.
We claim as our invention: 1. A device for coating paper in a continuous manner as it comes from the driers of; a paper machine comprising, means for passing the web said web is given a preliminary set during passage of the web in the remaining major portion of its travel over the surface of said drum.
2. A device for coating a fibrous web as it comes from the driers of ,a multiple drier paper machine comprising, an auxiliary heated drier drum, a pair of driven contacting rolls disposed adjacent said auxiliary drier drum, means for passing said web between said contacting rolls and around an appreciable degreeof the drum surface, whereby said web is brought into heat interchange relationship with the drum surface, said driven contacting rolls maintaining said web in a substantially constant degree of tension as -it passes around said drum surface, a coating unit disposed adjacent said drier drum comprising, a plurality of osculating rolls, one of said osculating rolls contacting said web upon said drum at a point onsaid drum spaced from the point at which the web initially contacts the drying drum and after the web has traveled over a minor portion of its total. travel oversaid drum surface to preliminarily heat the web prior. to the application of coating thereto, means for depositing a coating material upon said osculating rolls, the osculating roll in contact with said web being adapted to deposit a smooth film of coating material of relatively uniform thickness upon the web while the webis passing over thev drier drum, the heat of said drier drum assisting to preliminarily set the coating material on said web during passage of the web in the remaining major portion of its travel over the surface of said drum.
3. A device for coating a fibrous web as it comes from the driers of a multiple drier paper machine comprising, an auxiliary heated drier drum, a pair of driven contacting rolls disposed adjacent said auxiliary drier drum, means for passing said web between said contacting rolls and around a major, portion of the drum surface, whereby said web' is brought into heat interchange relationship with the drum surface, said driven contacting rolls maintaining said'web in a substantially constant degree of tension as it passes around said drum surface, a coating-roll disposed in contact with the web upon said drum at a point on said drum spaced from the point at which the web initially contacts the drying drum and after the web has traveled over a minor por- I of paper from the driers of the paper machine to Y the surface of a heated drier drum, means for carrying said web around a major portion of the surface of said drying drum, whereby said web is ,brought into heat interchange relationship with :the drum surface means for maintaining the ,tension of the web substantially constant during its travel around said drying drum, a coating unit disposed adjacent said drying drum comprising a roll which contacts said web upon said drum mt a point on said'drum spaced from the point tion of its total travel over said drum surface 'to preliminarily heat the web prior to the application, of coating thereto, means for depositing a coating material uponsaid coating roll, the coating roll in contact with said web being adapted to deposit a smooth film of coating'material of relatively uniform thickness upon the web while the web is passing over the drier drum, the heat of said drier drum assisting to preliminarily set the coating material on said web during passage of the web in the remaining major portion of its .travel overthe surface of the drum.
HOWARD B. RICHMOND.