US2474691A - Web coating apparatus - Google Patents

Description

June 28, 1949. w. A. ROEHM WEB comma APPARATUS 4 Sheets-Shae 1 Filed March 20, 1946 INVENTOR WILLIAM AROEHM am" ATTO NEY .5 Q@QQO June 28, 1949. w. A. ROEHM 2,474,691

WEB COATING APPARATUS Filed March 20, 1946 4 Sheets-Sheet 2 Ooo INVENTOR 4 WILLIAM A. ROEHM ORNEY June 28, 1949. w. A; ROEHM 2,474,691 WEB COATING APPARATUS Filed larch 20, 1946 4 Sheets-Sheet s 4 INVENTOR .WILLIAM A. ROEHM a AAORNEY I W. A. ROEHM WEB COATING APPARATUS June 28, 1949.

4 Sheets-Sheet 4 Filed larch 20, 1946 mvzmon WILLIAM A. RQEHM uNi'ran STATES PATENT orrica wen COATING maaarus William A. Roelun, Rockvllle Centre, N. Y., ac-

signor, by meme amignmentgto Vlrtu, Inc... Brooklyn, N. 1., a corporation of New York Application March. 20, 1946, No. 655,831

material is applied to the web.

. The object of this invention is to provide a more efiicient and economical, method of and apparatus for handling various types of coating materials,

more particularly coating materials of theheavier or viscouskinds and for applying them to a traveling web in sucha way as to produce a uniform coating of the desired thickness on the surface of the. latter.

12 Claims. (Cl. 9143) v z plied to the web. The web may be conveniently guided past this opening by a back-up roll adjustable toward and away from the forward lip of The method of this invention comprises, generally speaking, the feed of coating material to an outlet through a passage leading from a reservoir. containing such coating material. One or more of'the walls of this passage moves in the direction of the outlet and contact with the coating material and thefriction (skin or surface friction) between the moving passage and the material is utilized to feed the coating material through the passage to and through the outlet.

As the coating material issues from theoutlet, it impinges upon and is applied to a web traveling past said outlet and at such distance therefrom asto lay upon the web a coating of the desired thickness. The depth or thickness of this coating may be controlled. by regulating the distance between the outletand the web. o

In practice, the moving portion of the passage which leads. to the outlet may conveniently. comprise a portion of the surface of one or moretravcling endless belts or a portion of the convex sur- ,rotation oi, the roll .orroils .to, and through a tapering throat leading; to. a constricted mouth,

thelips oflwhich are adjustable to varythe distance between them and thusprovide an outlet ,opening .fiilipropriate to the, .particular material fed and thlthickness or t to be apthe outlet mouth, which acts as a smoothing and leveling dam or weirto insure that the web, as it leaves the point of application, will carry a smooth coating of uniform depth.

The apparatus of this invention provides for heating of a coating material to be applied and for the maintenance of this material at satisfactory working temperatures during application. Coating materialsof widely difierent characteristics and types may be applied in accordance with this invention, including heavy viscous plastic coating compositions which haye been extremely diffcult to handle with prior known procedures and apparatus.

Features of the invention. other than those referred to, will be apparent from the hereinafter detailed description and appended claims, when read in conjunction with the accompanying drawings.

The accompanying drawings show different forms of apparatus embodying the present invention and adapted to carry out the method of this invention, but the showing therein made is to be understood as illustrative, only, and not as defining the limits of the invention. In the drawings:

Figure 1 is a sideelevation of apparatus embodying this invention with a part of the upper portion thereof broken away in the interest of clearness.

Figure 2 is a, fragmental plan view showing the near side of the apparatus as illustrated in Figure 1, the far side being-of the same construction. In Figure 2 the back-up roll of the traveling web is removed and a portion of the tank cover is broken away.

Figure 3 isa section of the line 3-4 of Figure 2.

Figure 4 is a section on the line 4-4 of ure 1. V

Figure 5 isa plan view of a modified form of construction.

Fig-

. Figure 6 is a section on the. line 6-4 of Figure 5.-

fountain having therein a chamber 2 to contain coating material 3. The fountain is shown as provided within its walls with electric heating elements 4 in the form of resistance coils, although, if desired, steam, hot water or oil passages may be employed in lieu thereof for heating purposes. In any event, the walls of the tank are heated to a suificient temperature to maintain the coating material in satisfactory condition for application. The top of the tank or fountain is provided with covers 5 to prevent solvent evaporation or oxidation or slopping over of the coating material during-operation of the pp tu I Immersed in the coating material in the fountain are two feed rolls 6 and I. These rolls are mounted on shafts 8 extending through the I4 is a plate or blade 25 secured to the block by means of screws 26 which pass through elongated holes 21 in the blade to permit of adjustment thereof. The forward edge of this blade 25 is undercut to form a lip 28 which will be hereinafter referred to as the rear lip. The forward lip of the feed opening is in the form of an interchangeable bar or strip 29 which constitutes a weir or dam as will be presently explained. This strip 29 is removably seated in a channel extending transversely along the block l5 and it is adapted to be clamped firmly in the channel by means of a clamp plate 3|] held in place by screws 3|. The forward edge of the strip 2!! is chamfered opposite end walls of the tank which are progether for simultaneous rotation in opposite directions. The gearing is of any conventional type which will permit one or both of the shafts to be adjusted toward and away from one another to vary the distance between the peripheries of the rolls 6 and T. A heat insulating plate l3, such as asbestos, underlies the tank so that undue heat is not transmitted to the foundation or base plate.

The rolls 6 and 1 are positioned, in the structure shown in these figures, with their axes in the same horizontal plane, but are tangentially spaced apart to provide between them a constricted passage. The minimum horizontal width of this passage may be below the surface of the pool 3 of coating material, as clearly shown in Figure 3.

Above this constricted area and extending transversely of the tank are two feed passage blocks indicated by the reference characters l4 and IS. The block I4 will hereinafter be termed the blade block, while the block IE will be termed the dam or weir block. These two blocks are so shaped at their under sides as to form, along the lower edges of their adjacent bases, knife edges l6 and I1, respectively, adapted to engage with the peripheries of the rolls 6 and l and form therewith substantially liquid tight joints. The adjacent faces of these blocks are upwardly inclined to form an upwardly tapering passage or throat it between them, terminating at its upper end in a relatively constricted mouth IS in the form of a slot extending from the front to the back of the machine.

Both blocks l4 and I5 are provided at their opposite ends with projecting flanges operating in horizontal slides 2] (Figure 4), so that they may be adjusted in said slides to contact the knife edges l6 and ll of the respective blocks with the peripheries of the feed rolls 6 and I. The adthese screws, as well as the flanges 20, are adapted to be rigidly secured in position by clamp plates 23 (Figure3) clamped down by machine screws 24 Positioned on the upper face of the blade block and the clamp plate so is-complementarily chamfered, so that when the screws 3| are tightened the forward lip strip 29 is clamped firmly in position.

The blocks l4 and I 5 are shown in Fig. 3 as cored for heating units 4, so that these parts may be kept at the desired temperature.

Extending upwardly from the frames l2 at the oppositesides of the machine are upstanding guides 32, tied together at their tops by plates 33 and mounted for vertical sliding adjustment between the guides 32 at the front and back of the machine are bearing blocks 34, each of which carries a bearing. 35 and these two bearings support the opposite ends of a shaft 36 which projects through them. To one end of this shaft'is attached an appropriate gear, so that it may be driven, and this gear is interlocked by suitable into the top of each side frame i2 beneath thecorresponding bearing block 34. The head 39 of each of these stop screws is provided with perforations into which a wrench maybe inserted, to vertically adjust the screw which may be then looked in adjusted position by means of a lock nut 40. These stop screws very accurately adjust the spacing between the back-up roll 31 and the upper edge of the dam 29 for the bearing blocks of the back-up roll seat firmly upon these stop screws which limit the downward movement of this roll.

The web to be coated, indicated in the drawings by the reference character W, is adapted to be led about the roll 31, as'shown in Fig. 3. In order to provide for convenient leading of the web about the roll, previous to the coating operation, or for replacement of theweb in the event of breakage, for any reason, it is desirable that the roll be retractable upwardly away from the fountain. To provide for this, each of the bearing blocks 34 is provided with vertically spaced apart lugs 4| '(Fig. 1). A vertical rod 42 passes loosely through holes in these lugs and between the lugs a bracket 43 is rigidly secured to the rod positioned a compressiomspring 41. The springs ll assi t ra ity-in ho th b ing ocks I a ainst, the? stops 3 L Ma atee wine main. the n -ei Y Pa ti es and. t u ere i,

H y; J. 1N}; H5 The, ,racks "45 'at,.the ,i'ront and ,ba'ck ofthe machine extend v'ega au and. each meshes with anadjusting pinion 48. These wo ,pinichs are fixed on a horizontalshaftlfwhich is mounted to rotate in lavcv ,of; the, upright guides l 32., The

shaft 49 projects, beyond one of the guides and sin-adequate supply of coating ma e ial; o gi ve'j isisquaredat 50 so that ,ahand wheel or wrench-1 blocks 34 engage with the stop screws 38, which act to positively limit the relation between the periphery of this roll and the dam lip 29. When in this adjustment, the, set, screws 44 are tightened so as to preclude inadvertent lifting of the back-up'roll due to the tension of the paper a on theweb ,or for any other reason. i

In utilizing the apparatusithus far described to coat a web, the chamber, 2 of the fountain is charged with the desiredcoating material 3 up to a surface levelwpreferably above the horizontal planeof the axes ofthe feed rolls 6 and I, so that these feed rolls dip into the bath. If the coating material is such as requires heating ,thereof or if this is preferable. the heating units 4 are energized for this purpose and the bath is brought up to, the desired coating temperature... ,Themachine is then started and the feed rolls are caused; to rotate in opposite directions, the roll at the left 7 v of Figure 1 rotating in a counterclockwisedirection, while the roll at the right is rotated in clockwise direction. Thus the peripheries of these rolls rotate in the direction of the outlet mouth andas they thus rotate, they create skin friction with the coating material in whichthey are immersed. The coeflicient of this friction will of course depend upon several factors. such as the character of the coating material, the speed at.

which the rolls are driven, the spacing betweenl the rolls and other like factors? In any event practice has demonstrated that, as the rolls rotate in the manner described, they set up, a verydefinite flow oftheliquid upwardly between the spaced bite, of the rolls and in so doing feed the coating material upwardly into the throat i8.

The throat fills very quickly and the material therein is put under pressure of the inflowing f material which causes suchmaterialto be forced through the mouth l9 of the outlet passage'and,

between the lips, 28,; and 29 into contact with the,

, web W traveling, about the backing, r0113], 1

The relative adjustment between the feed rolls B andfl i. e their distanceaparatheir speed of operation, and the adjustedposition pf their-ear blade 25 will in a larg e mea sure regulate the amount of coating material fedbetween the lips, to the web and thespeed of, the web and the; a

thickness of the coating desiredwill, in a-large measure,ldictate the amount of-coating material, that shouldbe fed. The optimum condition is that wherein substantially the same amount of coating material is fed to the web as willprovide undue backing up of the? coating material over the topofrtherear blade 2!. Slight backing up,

. r t insuresan adequate sunplllofjcoatingmat fialtol give, I the desired thickness Moi, coating jan serves aw ens ar un ven, fii bi sp the eb such as indicated jin Eigurei.3,,. is de sirahl surface Whenthis sates tin erate; m at; parts properly timed, the Web willmoye, past the outlet mouthat a speed to pick} up more than the desired, coating, but as the webpasses'pver, I the dam or weir lwhich constitutes the forward lip 29, this clam willpermit the web to carry along with it only suilicient coating material to give a V uniform coating of the predeterminedlthickness. The top edge of thedam isshown as straight} and relatively thin so-as; not to produce undue dragging on the coating material: at the same time it permits the passage thereoverof anab solutely smooth uniform surface. In other words,

the upperedgeof the dam levels and smooths the exposed surface .of, the coating and experiq ence has shown that even though the web contains marked irregularities, suchas is found, for,

example, in crepe Kraft paper, the dam will insure an absolutely smooth. and uniform exposed surface on the resulting coating. If the upper edge of the, damtisnotched 0r serrated, how-,

ever, it will form striations in the exposed sur- .face of the coated film and if this dam is rectilinearly reciprocated, these striationsflwill be of a wavy nature. I The thickness of the coating will of course de pend upon, the spacing between the surface of o the web and the top edge, of the dam, and this 1 spacing is so accurately controllediand regulat ed by the stop screws that micromatic adl justment of the thickness of the coating isread 1 ily attainable.

end of difiiculty, may be efiectually andreadily handled and applied to the. web by this appainvention.

Qne of the few conditions under which difl3- culty may be experienced in practising this invention through the upright feed of coating material to a web bypassing it'between feed rolls, as stated, is that wherein the coating material is so heavy and 'non-flowable thatthe rotation of the 'rollswill simply feed the material in con tact therewith while theremainder of the bath will be so stiff that it will not quickly-flow into contact with the rolls to displace the materialalready fedj In 3 dealing'with 'such'heavy bodied materials,'-it has been found-thoroughly prac-y tical to operate the a paratus in inverted p051; tion so that, for example inEigur' 3; the entire structure I is inverted, with the 'web"ru'nnin'g* underneath andthe tank inverted and above}the 1 web, so, that 'the weightof the material in the '1 tank will cause it to beat down upon the feed? rolls and 1 an re t l y"c curr n v contact with'theserolls; so that the material canf for, a coating C of adequate thickness without (5 be frictionally engaged therewith and f rtfcd.

An important feature of this invention is found in-the wide variety of coating materials which may be applied according to thisinvention. Very heavy bodied and extremely tacky materials,,,, which under prioriprocedures have produced no tank IIH.

thereby through the throat and mouth to the web. When the apparatus is inverted'as stated, the top plates shown in Figure 3 will form the bottom of the tank and should be made thicker and provided with heating elements, while the bottom of the tank shown in Figure 3 should be replaced by plates, such as the top plates 5.

Heretofore it has been common to apply viscous coating materials by passing them beneath a cutter in spaced relation to a web. This practice places quite a strain on the web which not infrequently causes tearing of the latter. With this invention, however, it is found that very viscous materials may be handled and applied evenly in the manner stated without placing any undue stress on the web. Roll 31 in practice, may be either positively driven or it may be rotated by the web as the latter is drawn about the same under tension.

In the form of the invention as thus far described, two opposed feed rolls are utilized to feed the coating composition to the web. This feed is substantially a vertical feed. It is possible, however, to utilize one roll for this purpose either as .a vertical feed or as a lateral feed and in fact two rolls may be utilized for a lateral feed. However, byway of illustration,

Figures 5 and 6 show a single roll lateral feed. In these figures I III designates the tank or fountain containing the coating material I03 in the chamber I02. A single feed roll I06 is immersed in the bath and with the periphery of this roll is engaged the knife edge of the block H5. This block is carried by a vertically adjustable plate I23 adapted tobe locked in the desired position of adjustment by set screws I24. The forward lip or dam I2! is rigid with the block H5 and the plate I23.

The bottom of the tank is curved upwardly beneath the roll HIB'to merge into the lower wall of the throat II8 which tapers to an outlet mouth H9 below the dam- I29. The plate I25 corresponds to the plate 25 and is adjustable toward and away from the dam I29 by means of adjusting screws I22.

The stop screws I38 correspond to the screws 38 and are adapted to bear against the blocks I34 which carry the bearings for the back-up roll I31. The bearing blocks I34- in these figures are 8 I of skilled workmen for when once in proper adjustment, this operation requires minimum supervision. Inasmuch as the feed rolls rotate within the liquid inthe fountain, they will serve to agitate and stir up the liquid unless it is extremely heavy and in so. doing will preclude stratification or settling as is so often the case with gravity feeders.

The feed roll or rolls have been found to operate with marked efficiency for the purposes stated. They produce the desired pressure on described.

mounted on a dove-tail slide s for longitudinal adjustment in a correspondingly shaped guide in a plate I32 rigidly mounted with respect to the To the slide s are affixed racks H5 meshing with pinions I48 and shaft I49 which carries these pinions is squared at I50 to receive a hand wheel or wrench by means of which the back-up roll I31 may be moved toward and away from the fountain for the same reason as the roll 31 is moved toward and away from its subjacent fountain.

Heating elements I04 serve to maintain the parts at the desired operating temperatures.

In this form of the invention the single feed roll I06 will act against only one side of the body of the coating material in the passage to the converging throat, but the friction with this portion of the material will be sufiicient tofeed through the constricted throat most of the coating materials that are commonly used in the coating of webs. The feed, however. is not as efiicient as a double roll feed hereinbefore described.

The apparatus'of this invention is relatively simple to operate. *It does not require attention- The foregoing detailed description sets forth the invention in its preferred practical form, but

the invention is to be understood as fully commensurate with the appended claims.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is: I

1. An apparatus comprising: adapted to contain a pool of coating material and having a. feed passage leading to an outlet mouth, a movable memberhaving a surface p0- sitioned in close proximity to the outlet mouth and adapted to travel past the same, andat least one feed roll contacting said pool and a portion of the circumference of which forms part of the wall of the feed passage, said roll being rotatable in a direction to feed the coating material from the pool through. said passage to and through the outlet mouth and against said surface under the thus mechanically generated hydraulic pressure, said outlet mouth being provided adjacent its forward edge with a dam spaced from said surface a distance substantially equal to the thickness of the coating desired on the surface.

2. An apparatus comprising: adapted to contain a pool of coating material and having a feed passage leading to an outlet mouth, a movable member having a surface positioned in close proximity to the outlet mouth and adapted to travel past the same, and at least one feed roll contacting said pool and a portion of the circumference of which forms part of the wall of the feedpassage, said roll being rotatable in a direction to feed the coating material from the pool through said passage to and through the outlet mouth and against said surface under the thus mechanically generated hydraulic pressure, said'outlet mouth having at its forward edge a dam spaced from said surface a distance substantially equal to the thickness of the coating desired on said surface and at its rear edge an adjustable lip to regulate the area of the outlet mouth.

3. An apparatus comprising: a fountain adapted to contain a pool of coating material and having a feed passage leading to an outlet mouth, a movable member having a surface positioned in close proximity to the outlet mouth and adap ted to travel past the same, and at least one feed roll contacting said'pool and a portionof the circumference of which forms part of the wall of the feed passage, said roll being rotatable in a direction to feed the coating material from the pool through saidpassage to and through the outlet mouth and against said surface under the thus mechanically generated hydraulic pressure, said outlet mouth being provided adjacent its forward edge with'a dam spaced from said sura fountain a fountain face a distance substantially equal to the thickness of the coating desired on said surface, and means for varying the spacing between the surface and the dam to correspondingly vary the thickness of the coating on said surface.

4. An apparatus comprising: a fountain adapted to contain a pool of coating material and having an outlet throat leading to an outlet mouth, a movable member having a surface positioned in close proximity to the outlet mouth and adapted to travel past the same, opposed feed rolls spaced from one another to form between them a passage leading to said throat and in contact with opposite walls thereof, said rolls contacting the pool of coating material and rotatable in counter directions to collectively feed such material between them from the pool to and through the throat and through said outlet mouth to and onto said surface under the thus mechanically generated hydraulic pressure.

5. An apparatus comprising: a fountain adapted to contain a pool of coating material and having an outlet throat leading to an outlet mouth, a movable member having a surface positioned in close proximity to the outlet mouth and adapted to travel past the same, opposed feed rolls spaced from one another to form between them a passage leading to said throat and in contact with opposite walls thereof, said rolls contacting the pool of coating material and rotatable in counter directions to collectively feed such material between them from the pool to and through the throat and through said outlet mouth to and onto said surface under the thus mechanically generated hydraulic pressure, said outlet mouth being provided adjacent its forward edge with a dam spaced from said surface a distance substantially equal to the thickness of the coating desired on said surface.

6. An apparatus comprising: a fountain adapted to contain a pool of coating material and having an outlet throat leading to an outlet mouth, a movable member having a surface positioned in close proximity to the outlet mouth and adapted to travel past the same, opposed feed rolls spaced from one another to form between them a passage leading to said throat and in contact with opposite walls thereof, said rolls contacting the pool of coating material and rotatable in counter directions to collectively feed such material between them from the pool to and through the throat and through said outlet mouth to and onto said surface under the thus mechanically generated hydraulic pressure, said outlet mouth having at its forward edge a dam spaced from said surface a distance substantially equal to the thickness of the coating desired on said surface and at its rear edge an adjustable lipto regulate the area of the outlet mouth.

7. An apparatus comprising: a movable member having a surface traveling therewith, a stationary outlet mouth positioned in close proximity to said surface, spaced apart throat forming members leading from said outlet mouth in divergent relation, 2. pair of feed rolls mounted on parallel horizontal axes and contacting with the divergent portions of the throat forming members on one side of the common plane of the axes of said rolls, a fountain adapted to contain a pool of coating material with which said rolls contact on the opposite side of said common plane, and means for rotating said rolls in opposite directions to feed the coating material from the pool between the rolls to and through the throat between the throat forming members ber having a surface traveling therewith, a stationary outlet mouth positioned in close proximity to said surface, spaced apart throat forming members leading from said outlet mouth in divergent relation, a pair of feed rolls mounted on parallel horizontal axes and contacting with the divergent portions of s the throat forming members on one side of the common plane of the axes of said rolls, a fountain adapted to contain a pool of coating material with which said rolls contact on the opposite side of said common plane, and means for rotating said rolls in opposit'e directions to feed the coating material from the pool between the rolls to and through the throat between the throat forming members to and through the outlet mouth and onto said traveling surface under the hydraulic pressure generated by the thus rotating rolls, and a leveling member beyond the outlet mouth and spaced from said surface a distance equal to the desired thickness of the coating on said surface.

9. An apparatuscomprising: a fountain adapted to contain a pool of coating material and having a feed passage leading to an outlet mouth, a movable member having a surface positioned in close proximity to the outlet mouth and adapted to travel past the same, at least one cylindrical feed roll independent of the outlet mouth and positioned rearwardly of and in spaced relation thereto, said roll contacting said pool and a portion of the circumference of which roll forms part of the feed passage back of the outlet mouth, and means to rotate said roll in a direction to feed the coating material from the pool through said passage and through the outlet mouth and against said surface under the thus mechanically generated hydraulic pressure.

10. An apparatus comprising: a fountain adapted to contain a pool of coating material and having a feed passage leading to an outlet mouth, a movable member having a surface positioned in close proximity to the outlet mouth and adapted to travel past the same, at least one smooth surfaced cylindrical feed roll independent of the outlet mouth and positioned rearwardly of "and in spaced relation thereto, said roll contacting said pool and a portion of the circumference of which roll forms part of the feed passage back of the outlet mouth, and means to rotate said roll in a direction to feed the coating material from the pool through said passage and through the outlet mouth and against said surface under the thus mechanically generated hydraulic pressure.

11. An apparatus comprising: a fountain adapted to contain a pool of coating material and provided with an outlet passage leading to an outlet mouth having normally stationary walls, a portion of the wall of the passage independent of and back of the outlet mouth and in contact with the pool of coating material being movable in th directionof said mouth, and means for moving the movable portion of the wall of the passage in said direction to feed coating material from the pool through the passage to and out through the outlet mouth.

12. An apparatus comprising: a fountain adapted to contain a pool of coating material and having a feed passage leading to an outlet mouth, a member movable across the mouth in ff rial issuin: from said mouth will directly imupon the surface of said member, at least one teed roll having a smooth cylindrical periphery contacting said pool and positioned wholly back oi. the outlet mouth and spaced therefrom, a portion of the periphery of said roll forming a part of the wall 0! the teed passage. and means to rotate said roll to feed the coating material from the pool throu h said passage and through the outlet mouth and apply it against the surface or said movable member by virtue of the thus mechanically generated hydraulic pressure.

WILLIAM A. ROEHM.

l2 assurances crrsn The following references are or record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,421,884 Yohns July 4, 1932 1,933,963 Bradner Nov. 7. 1933 1,945,065 Mosslang et al Jan. 30. 1934 1,993,772 Case Mar. 12. 1935 1,994,263 Woodward et a1. Mar. 12, 1935 2,054,448 Russell Sept. 15, 1936 2,119,480 Codwise May 31, 1938 2,351,271 Leguillon June 3, 1944

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