US2157213A - Coating device for wet paper - Google Patents

Description

y 3 w. M. NASH 2,157,213

COATING DEVICE FOR WET PAPER Filed July 2, 1956 5 Sheets-Sheet l y 1939- W. M. NASH 2,157,213

COATING DEVICE FOR WET PAPER Filed July 2, 1936 3 Sheets-Sheet 2 M. NASH 2,157,213

COATING DEVICE FDR WET PAPER Filed July 2, 1936 s Sheets-Sheet 3 Patented May 9,1939

COATING DEVICE FOR WET PAPER William M. Nash, Chicago, Ill., assignor, by direct and mesne assignments, of one-fourth to Roy A. Nash, New Rochelle, N. 'Y., one-fourth to Mary Jones, Neenah, Wis., and one-fourth to Marie Duvall Nash, Neenah, Wis.

. Application July 2, 1936, Serial No. 88,551

4 Claims. (Cl. 82-40) This invention relates to improvements in a device for coating or opacifying paper and refers specifically to improved means whereby a coating or opacifying material may be uniformly and smoothly applied to a continuously travelling web of paper by the use of "a dandy roll.

It has heretofore been proposed to coat or applyopacifying materials to a continuously travellingpaper web by means of a dandy roll. However, difficulty has been encountered in obtaining a smooth, unspotted orunstreaked coating. These difficulties are primarily due to the manmeshes of the screen surfaced roll. In this manner, a pool of coating or opacifying material is prevented from accumulating within the dandy roll adjacent the critical point of application of the material to the web.

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

In the drawings, Fig. 1 is an end elevation of a dandy roll which is provided with the improved means comprising my invention.

Fig. 2 is a top plan view of the device shown ner in which the coating or opacifying material in Fig. 1.

is initially applied to the dandy roll prior to its Fig. 3 is a sectional view taken on line 3-3 of application to the web, the manner of applica- Fig. 1.

tion being such that it was substantially impos- Fig. 4 is a detailed sectional view taken on line sible to confine the coating or opacifying mate- 4-4 of Fig. 1.

rial to the surface of the dandy roll. That material which escapes or seeps through the surface of the dandy roll accumulates within the roll and eventually forms a pool at the lower arc of the roll adjacent the point of application of the coating or opacifying material to the web. Here the accumulated material tends to again pass through the meshes of the foramin'ated surface of the roll and as a consequence irregular deposits of coating or opacifying material have been discharged upon the passing web. I

My invention provides means whereby coating material can be conveniently applied to the surface of the dandy roll, the manner of application being such that the coating or opacifying material is substantially entirely confined to the surface of the roll and means is provided whereby that small amount of material which may pass into the interior of the dandy roll is'prevented from accumulating adjacent the line of application of the material to the surface of the web. Briefly described, my invention resides in applying coating or opacifying material in the liquid state to a flexible apron or sheet which rests or drags upon the upper foraminated surfaceof the dandy roll. By applying the coating or opacifying material in this manner the same is transferred to the foraminated surface along a plane tangent to said surface. Hence, by surface tension or capillary phenomenon the coating or' opacifying material is carried on the surface of the roll, there being no head or other. force tending to cause the material to pass through the meshes or interstices of the foraminated roll surface. Further, the roll is so mounted as to permit a trough to be carried within the interior of the roll to catch or retrieve any coating or. opacifying material which may seep through the Fig. 5 is a detailed sectional view taken on line-5-5 of Fig. 1.

Referring in detail to the drawings, I indicates a dandy roll assembly, the roll of which is utilized to apply coating or opacifying materialto the surface of a newly formed paper web 2 which is carried upon the paper forming screen 3. The

' assembly I may be positioned over the screen 3 at a point along the direction of travel of said screen above the location of the suction boxes (not shown). In the usual Fourdrinier machine the pulp after being discharged or fiowed upon the paper forming wire passes over a series of tube rolls wherein a considerable quantity of aqueous carrier of the pulp is removed. After the wire has passed over the last tube roll it travels over a plurality of suction boxes wherein further quantities of the aqueous carrier are removed. It is preferable that thedandy roll assembly I be so positioned as to be located approximately midway between the initial and final suction box.

A pair of rails 4 traverses substantially the entire length of the wet end of the Fourdrinier machine and comprises a portion of the paper machine frame. The remaining portion of the frame is not illustrated in the drawings inasmuch as the construction of the usual Fourdrinier paper machine is well known to those skilled in the art. ,A pair of castings 5 and 6 are mounted 'upon and secured to opposite rails 4 by means of bolts-l or the like. The castings 5 and 6 are similar in construction and to the upper portion of each an arcuate shaped arm 8 is secured, said arms being identical in construction. At the free end of each of the arms a bar 9 is pivotally .inounted as at ID in Fig. 1. The bars 9 each comprises a curved section II and a curved section I2 integrally joined by a straight section l3. The end of the curved section II of bar 9 is forked or bifurcated providing a slot |4 between the bifurcations in which a roller I5 is positioned, said roller being carried upon pin i6 which projects through both bifurcations and the end of section i3. The straight section l3 of bar 9 is offset with respect to the curved section II and is integrally joined with the lower portion of the curved section l2. The lower end of curved section I2 is also forked or bifurcated and is provided with a slot l1 in which a roller I8 is disposed, said roller being mounted upon pin l9 which projects through both bifurcations and the end of the straight section l3. The upper end of each of the sections l2 of the bars 9 iscurved at an angle to the remaining portion of said section and terminates in an arm 20.

Each of the castings 5 and 6 is provided with an opening 2| and 22 respectively through which the arms are positioned, said arms projecting outwardly at their ends from the castings 5 and 6. Lugs 23 and 24 are formed integral with the castings 5 and 6 respectively and project outwardly from said castings. Pins 25 and 26 are extend upwardly from said lugs. .Coil springs 21 and 29 embrace pins 25 and 26 respectively and are confined between lugs 23 and 24 respectively and the outwardly extending ends 20 of sections l2, through which pins 25 and,26 project. 29 isjournalled adjacent its opposite ends in the castings 5 and 6 and a handle 39 is keyed or otherwise immovably secured to one end of said shaft. A pair of cams 3| are rigidly positioned upon shaft 29, there being a cam 3| within each of the openings or recesses 2| and 22., Cams 3| are eccentrically positioned upon shaft 29 and are disposed immediately beneath each of the extending arms 20. The arrangement is such that, when handle 30 is manipulated, the surfaces of cams 3| are rocked into contact with the lower edges of the arms 20 and, consequently, raise said arms thereby moving bars 9 about the pivot points In in a counterclockwise direction as viewed in Fig. 1.

A dandy roll 32 is positioned between the opposite castings 5 and 6, said roll being provided with a foraminated or screened surface 33, the meshes of said screen being in the neighborhood of 50 per inch. The ends of the roll 32 comprise rings 34 which are provided with grooves 35. In operation roll 32 is positioned between arms 8 and bars 9 and the ends of said roll are supported by means of rollers I5 and I8, said rollers being adapted to engage rings 34 in grooves 35 as illustrated in Fig. 5. It can readily be seen, therefore, that the dandy roll 32 is not supported from a central axis but is suspended or rests upon rollers l5 and |3, which in turn are carried by bars 9, the ends of which (20) rest upon springs 21 and 28. It can readily be seen, therefore, that the dandy roll 32 is ultimately resiliently mounted or supported upon springs 21 and 28.- Each of the sections and I2 is provided with an aperture 36 and 31 respectively which carry coil springs 38 and 39 respectively. Plugs 40 and 4| respectively are slidably positioned within the apertures 36 and 31 and project outwardly from the surfaces of sections II and I2. The outer ends of plugs 4|! and 4| are adapted to project into the grooves 35. In view of the fact that rollers l5 and I8 are positioned within grooves 35 adjacent the lower portion of the rings 34, and plugs mounted upon lugs 23 and 24 respectively and said ends being provided with apertures. A shaft 40 and 4| are positioned within said grooves at a higher portion of said rings, axial movement of the roll 32 is effectively prevented. Plugs 40 and 4| are preferably constructed of wood saturated with oil or may be constructed of any so-called self-lubricating material.

Upright members 42 carrying outwardly extending lugs 43 at each of their lower ends, are mounted upon the opposite sections l3 of bars 9, said upright members being spaced from each other as shown in Fig. 1. Each of the lugs 32 is apertured and bolts 44 function to secure said lugs to the sections l3. The positioning of the upright members 44 is such that said members pass axially through the interior of roll 32. A trough 45 is secured at each of its longitudinal edges to the upright members 42 whereby a tray is provided within roll 32 which traverses the length of said roll. A pipe 46 is also positioned axially within the interior of roll 32, said pipe being provided with a plurality of apertures 41 which open toward the interior surface of the foraminated roll 32. Pipe 46 is adapted to carry steam under pressure which is discharged through the apertures 41, the jets of steam issuing from said apertures being directed against the screen 33 whereby the same may be cleansed.

A supporting member 48 may be secured to the web by means of bolts or the like 49 of each of the arms 8, said supporting members projecting upwardly and each terminating in a U-shaped saddle 5|]. A bar 5| is adapted to rest at each of its ends within the saddles 5|], said bar being disposed parallel to the axis of the roll 32. A flexible apron 52 is secured adjacent one of its side edges to bar 5|. The apron 52 may be constructed of rubber, rubberized cloth, felt or other flexible material. The free end of the apron 52 is adapted to rest upon-or drag upon the rotating surface of the roll 32 as indicated at 53 in Fig. 1. A sock t or saddle 54 may be integrally formed upon each of the webs of arms 8, said sockets or saddles being adapted to carry a pipe 55 which transversely spans the assembly. Pipe 55 is provided with a plurality of nozzles 56 which discharge toward the flexible apron 52. As will be hereinafter more fully described, pipe 55 is adapt ed to carry coating or opacifying material under pressure, which material is discharged into contact with apron 52 and ultimately deposited upon the foraminated surface of roll 32.

In operation, a newly formed relatively wet web 2 is carried upon the Fourdrinier wire 3 beneath the dandy roll assembly I. With roll 32 in operative position, arms 20 rest upon coil springs 21 and 28 and the foraminated surface 33 of' roll 32 exerts a slight pressure upon web 2 which passes therebeneath. Coating or opacifying material, comprising the usual coating substances in liquid suspension or solution, is passed through pipe 55 under superatmospheric pressure and is sprayed from nozzles 55 into contact with the concave surface of the flexible apron 53.

The free end of apron 53 rests upon or drags upon the upper surface of the roll 32 as the same is rotated by contact with the web 2 and the length of the apron is such with respect to-the relative position of the rod 5| and roll 32 as to have its lower edge terminate adjacent the top of roll 32. The length of the apron is also such that the end or lower edge thereof is disposed substantially tangentially to the roll 32. It can readily be seen, therefore, that the liquid material discharged to the surface of the apron flows downwardly along the concave side of the apron and flows substantially tangentially .onto the screen surface 33. Hence, there is substantially no force, such as an appreciable liquid head or pressure head which would tend to cause said coating or opacifying material to pass through the meshes or interstices of the foraminated surface. The mesh of the foraminated surface is, of course, sufficiently small to permit the retention, by surface tension,. of the liquid upon the surface.

Of course, it is substantially impossible to entirely prevent the material from passing into the interior of the rolland, hence, the trough 45 is provided within the roll adjacent the descending side thereof. The trough 45 is adapted to retrieve or catch the seepage through the surface of the roll and .thereby prevent an accumulation of coating or opacifying material within the roll.

adjacent its line of contact with the web. Of course, the trough 45 can be conveniently disposed within the roll because of the suspended mounting of the roll whereby no interfering spokes or radial arms are necessary.

I claim as my invention:

1. In combination with a paper making machine wherein a relatively wet newly formed web is continuously carried forwardly upon a paper forming wire, means for coating a surface of said web comprising, a dandy roll supported above the path of travel of the web, the surface of said roll being in contact with said web, means for discharging coating material onto the surface of said roll whereby the same is deposited by said roll upon the surface of the web, said means comprising a flexible apron positioned above said roll, said apron contacting the roll, along a substantially tangential plane adjacent the top of the roll, and means for distributing a mobile coating material upon said apron, and a trough disposed within the roll and coextensive with the length thereof for retrieving coating material which passes through the surface. of the roll.

2. In combination with a paper making machine wherein a relatively wet newly formed web is continuously carried forwardly upon a paper forming wire, means for coating a surface of said web comprising, a dandy roll supported above the path of travel of the web, the surface of said roll being in contact with said web, means for diswithin the roll for retrieving coating material which passes through the surface of the roll.

3. In combination with a paper making machine wherein a relatively wetnewly formed web is continuously carried forwardly upon a paper forming wire, means for coating a surface of said webcomprising a roll having a foraminated surface positioned above the path of travel of the web, means for resiliently supporting said roll, the surface of said roll being in resilient contact with said web, and means for flowing coating material by gravity substantially tangentially on to the surface of said roll whereby the same is deposited by said roll upon the surface of the web, said means comprising a flexible apron supported above said roll, the opposite edge of which drags upon the surface of said roll along a substantially tangential plane, a trough disposed within the roll for retrieving coating material which passes through the surface of the roll, and spray means within said roll for discharging fluid into contact-with said foraminated surface to clean the same.

4. In combination with a paper making machine wherein a relatively wet newly formed web is continuously carried forwardly upon a paper forming wire, a frame positioned over the path of travel of said web, a dandy roll supported on said frame, the surface of said roll being in contact with said web, means for discharging coating material on to the surface of said roll,

a trough disposed within the roll for retrieving coating material which passes through the surface of said roll, a dandy roll support comprising a pair of spaced arms each of which is pivotally mounted at one end upon said frame, rollers carried by said arms upon which the lower portion of the periphery of the dandy roll rests, and resilient means for supporting the opposite ends of said roller carrying arms.

, WILLIAM M. NASH.

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