Paper coating device

Nov. 9, 1943

W. F. THIELE ET AL

PAPER COATING DEVICE

Original Filed May 31, 1939

2,333,902

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Nov. 9, 1943,

W. F. THIELE ET AL

PAPER COATING DEVICE

Original Filed May 31, 1939

2,333,902

Sheets-Sheet 2

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Patented Nov. 9, 1943

2,333,902

UNITED STATES PATENT OFFICE

2,333,902

PAPER COATING DEVICE

William F. Thiele, Wisconsin Rapids, Wis., and Warren E. Beadle, Sr., deceased, late of Wisconsin Rapids, Wis., by Warren E. Beadle, Jr., administrator, Biron, Wis., assignors to Consolidated Water Power and Paper Company, Wisconsin Rapids, Wis., a corporation of Wisconsin

Original application May 31, 1939, Serial No. 277,460. Divided and this application December 8,1941, Serial No. 422,040

Claims. (Cl. 91—48)

This is a division of our co-pending application Serial No. 277,460, filed May 31, 1939, on Paper coating device, and relates to improvements in apparatus for coating paper to provide a desirable printing surface thereon, and refers specifically to an apparatus wherein the rate of the transfer of the coating material to the paper web can be accurately controlled.

In all coating apparati wherein the coating material is applied to the paper web by means of a roll, and wherein no after operations are performed on the coated surface after the coating has once been applied, two predominant difficulties are encountered. First, the rate of passage of the coating material to the coating roll is difficult to control and it is essential that this rate be as uniform as possible; and secondly, it is difficult to secure a coating material of uniform fine texture and free from lumps continuously passing to the coating roll.

Iri our invention, an apparatus is provided in which the rate of passage of the coating material to the coating roll can be minutely controlled, and the coating material is so acted upon prior and during passage to the coating roll that its texture is maintained uniform.

Other objects and advantages of our invention will be apparent from the accompanying drawings and following detailed description.

In the drawings, Fig. 1 is a diagrammatic side elevational view of a coating unit embodying our invention.

Fig. 2 is a diagrammatic view illustrating the manner in which coating units similar to that shown in Fig. 1 may be utilized to coat both sides of a web.

Fig. 3 is a diagrammatic side elevational view of the coating rolls illustrated in Fig. 1, illustrating means for their relative adjustment.

Fig. 4 is a diagrammatic plan view of the coating rolls looking upwardly at the view shown in Fig. 3.

Referring in detail to the drawings, an embodiment of our invention is shown which is particularly adaptable for coating a strong web of paper such as cardboard, box board and heavy strong kraft paper. In this form of our invention rolls I and 2 perform the dual function of coating rolls and fountain rolls. Rolls ( and 2 are independently driven and the peripheral speeds of said rolls with respect to each other may be varied throughout a wide range. A dam 3 is positioned adjacent each end of the rolls I and 2 which function as closures at the nip of the rolls. The dam 3 may be constructed of hard rubber or any material which is frictionless in the presence of the usual coating material. We have found that the material known to the trade as “Eel-slip” operates very successfully as closure dams when utilized with coat5 ing material for coating paper.

A roll 4 is journalled in an intermediate portion of link 5. One end of link 5 is pivotally connected as at 6 to standard T. The opposite end of link 5 is pivotally connected as at 8 to rod 9 which 10 is threaded at its end and is engaged in the worm mechanism 10. The mechanism (0 is a conventional mechanism and functions to move rod 9 longitudinally upwardly or downwardly to adjust roll 4 toward or away from rolls ( and 2.

A web 11 of cardboard, box board, kraft paper or the like, is adapted to pass beneath rolls I and 2 and above roll 4, said latter roil being so adjusted as to permit the upper face of the web to raise a predetermined degree around the surfaces 20 θί rolls f and 2. This adjustment, of course, is provided through the mechanism 10.

In operation a predetermined quantity of coating material is continuously fed in the nip of rolls I and 2 and is confined thereby by means of 25 the dams 3. Preferably web 11 moves at a translatory speed greater than the peripheral speed of either rolls I and 2, and it is also preferable that roll 2 be driven at a relatively higher speed than roll I. In view of the fact that the weh ί I moves 30 faster than the fastest moving roll 2, a wiping action occurs between the web and the surface for the roll 2 whereby the coating material is smoothly and uniformly applied to the upper surface of the web 11. The amount of coating material that 35 is first applied to the web 11 is determined primarily by the speed of the roll 2. Roil I while applying a small amount of coating to the web I ί also acts as a wiping medium and spreads the coating material applied by the roll 2, roll I mov40 ing at a peripheral speed relatively slower than the translatory speed of web 11.

Referring particularly to Fig. 2 a diagrammatic arrangement is illustrated for coating both sides of a web 12 utilizing units similar to that illus⁴⁵ trated in Fig. 1. It is contemplated that the web 12 pass from the presses of a paper machine (not shown) or a portion of the drier section thereof. The web passes beneath the first unit (3 and the upper surface is coated as described in conjunc⁵⁰ tion with Fig. 1. The web is then passed around idler roll 14 and is carried around a plurality of drier drums (5. From the last drum 15 the web is carried around drum 16 and is passed through the second coating unit Π whereby the opposite ⁵ surface of the web is coated. After leaving the second unit 17 the web is trained around drier

2,3 drum 18, idler roll 19 and around drums 20. The web may then be rolled or cut into sheets in any conventional manner. It can readily be seen that by this arrangement both surfaces of the web 12 may be coated.

There are two general manners in which the amount of coating material carried by the coating rolls can be controlled; 1—By means of the variation in speed of the contacting rolls I and 2, each of which may be separately driven, and 2—By means of the pressure existent between the contacting rolls, means being provided for urging rolls I and 2 toward each other for controlling such pressure and means also being provided for controlling the degree of proximity of the rolls. Means by which these operations may be carried out are illustrated in the detailed views of Figs. 3 and 4. Thus a supporting frame having a pair of sides 21 support the rollers 1 and 2, the frame members being suspended from or mounted on a supporting surface or beam indicated at 22. Each side frame carries a depending standard 23 in the lower portion of which is mounted a bearing 24. A shaft 25 is journaled at each end in opposite bearings 24, said shaft carrying the roll I. The roll I is provided with a surface layer 27 which is preferably constructed of a medium hard rubber or other like semiresilient material. Standard 28 is pivotally connected as at 29 to each of the frames 21, each of the said standards carrying a bearing 30 at the lower end thereof. A shaft 31 is journaled at each end in one of the bearings 30, said shaft carrying the roll 2. The roll 2 is provided with a surface layer 33 which is preferably constructed of hard rubber or metal which effectively resists the wearing action of paper coating materials such as the usual clay dispersions. Each of the standards 28 is provided with an aperture 34 through which a link 35 is adapted to freely pass. One end of each link 35 is pivotally connected to a standard 23 upon each side of the roll i as shown at 36. The opposite end of each link carries a nut 37 which is threaded on the end of said link and serves to confine coil spring 38 between the standard 28 and a washer 39 disposed adjacent the nut 37. A boss 40 is Integrally formed upon each bearing 30 and is internally threaded to receive screw 41 having a hemispherical head 42. The arrangement is such that screw 41.may be so adjusted as to determine the minimum clearance between the surfaces of rolls I and 2 when standards 28 are urged toward standard 23 by means of springs 38. It can be readily seen that the hemispherical heads 42 carried by screws 41 abut against bearings 24 and thus limit the degree to which roll 2 may approach roll I. Referring particularly to Fig. 4, a motor 43 is directly connected to shaft 25 and the motor 44 is directly connected to shaft 31. By means of these motors, the rolls i and 2 may be independently driven and the peripheral speeds of the rolls with respect to each other may be varied through a wide range. In addition, by rotating the various contacting rolls at varying relatively peripheral speeds, a wiping and smoothing action is obtained which tends to render the film eventually applied to the coating roll smooth and of uniform thickness. Further, by maintaining a relatively small amount of coating material in the nip of the fountain rolls or gate rjlls, and by the peculiar agitation of said material, the coating material is never permitted to lie stagnant or dormant and lumps are never permitted to form.

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