US1520099A - Watermarking dandy roll - Google Patents

Description

Dec. 2-3, 1924. 41,520,099

G. W. VEROW WATERMARKING DANDY ROLL Filed May 127,' 1,924

nee., as, iaaa GEORGE W. VEEOW, OF LINCOLN, MAINE, ASSIGNOR TO EASTERN MANUFACTURING 00mm, 0F BOSTON, MASSACHUSETTS, .A CORPORATION OF MASSACHUSETTS,

WATERMARKING nanny. noni..

Application iled May 12, 1924. Serial No. 712,842.

To all 'whom t may concer/n: l f

Be it known that I, GEORGE W. VnRoW, a citizen of the United States, residing atil Lincoln, in the 'county of Penobscot and State of Maine, have invented new and useful Improvements in Watermarking Dandy Rolls, of which the following is a specification.

When watermarking is effected by the 'use of the usual dandy roll to which the desired marking element is attached, the dandy roll operating on the freshly laid pulp while it is soft and wet,'it has been found that the paper machine may have to be run slower than the rate determined by otherA conditions, in order to avoid excessive blurring off the mark. l

The dandy roll is ordinarily formed reticulated as of a fine mesh wire screen rolled into cylindrical form and sup orted by an internal framework. The ro rests by its weight on the pulp which passes thereunder onA the Fourdrinier wire 'and it is of very fine mesh so as to impart a leasing surface to the paper. If the dan y roll as commonly constructed and carrying watermarking elements is required to rotate rapidly to correspond with a relatively rapid passage of the paper, each watermarking element is brou ht down against the wet pulp suddenly and forcibly causing a splashing effect, some of the Water beneath the marking element being driven out forcibly laterally between VY-the wet sheet and the tightly woven gauze screen and displacing the iibers. Where the motion is relatively slow, however, this splashing ei'ect is not in evidencewater in the pulp passing through the wire mesh adjacent to the marking element without causing noticeable undesired displacement of the fibers. A ain, as the marking element leaves the pu p, if the action is rapid, a suction eEect is produced which acts to lift the fibers from the Fourdrinier wire, pausing their ends to be raised up, or even causing fibers to be'removed or picked from the wire. The raised ends are subsequently laid by passage through other portions of the paper machine, but in a dierent relation ship to that which they originally occupied in the web.l Thick and thin spots in the iinished paper adjacent to the watermark as well as an imperfect mark have thus rel have .f that the splash and suction effects at relatively high speed of the roll may be very greatly reduced by employing a relatively coarse mesh wire adjacent to the marking element to allow a relatively free passage' of air and water therethrough adjacent the margins thereof as the device approaches and recedes from the pulp. As

it is undesirable to form the roll surface as a whole of relatively coarse mesh, due to the undesirable rough, coarse surface texture which would be imparted to the paper from the imprint of the roll surface thereon, vit is the relatively coa'rs'e mesh portion does not leave its impress on the paper to a notice- 'able extent wherebyno impairment of the surface finish of the paper results therefrom. For a more completer understanding of this invention reference may be had to the accompanying drawings in Which Figure lis a perspective of a dandy roll constructed according tothis invention.

l Figure 2 is an enlarged detail showing the marking element and its support.

Figure 3. shows the roll cut to receive the sugport and marking element.

igure 4 'shows a manner of forming` the support integral with? the roll surfacingl wire.

Figures 5 and 6 are detail sections on lines 5-5 and 6-6 of Figures 3 and 4, respectively.

The dandy roll comprises the usual roll of ne wire mesh as atl supported' by any suitable form of frame Work in cylindrical form and having spiders 2 at its ends pro.

vided with trunnions 3 by which the roll may be supported for rotation about its a in position for its peri hery to rest 'by gravity on the freshly lai web of ulp as it passes thereunder while suporte by the Fourdrinier wire. At 4 is shown a watermarking element and as illustrated herein it comprises a series of letters 5 fixed to the outer face of the wire mesh so as to pro'ect slightly beyond the periphery of the roll so as to impart a localized pressure on the pulp as it comes in contact therewith as the'roll rotates.

relatively coarse mesh is only slightly larger than the outline of the entire marking element, and asshoWn in Figures?) and-5,- may be set Within an opening in the rela-- tively`fine fmesh wire' 1 2 which comprises the remaining portion of thel roll surface.

This section of relatively coarse mesh to which thegwatermarking element is at" .tached may be fixed to the relatively'ne mesh by any suitable means, as for example, by soldering.

ln place of forming the relatively coarse` mesh section as a separate piece from the relatively fine mesh portion of the roll, cerf-v size than those of the remainder of said tain of the Wires of the relatively line mesh material may be removed over a sulicient area to dene the desired relatively coarse mesh. section integral With the fine mesh portion. f This is shown, ,for example in Figures 4- and 6, in which each alternate 'Warp and weft Wire is cut adjacent to the margins of the Watermarkingelement, the sections thus cut 'being removed and the exposed ends of the cut 'Wires bent back underneath the exposed surface of the roll. While as shown a section of each alternate Wire is removed, two Wires outA of each three, or any other proportion, might be removed, if desired, thisresulting in a coarser mesh. In any event,- however, the Watermarking element is carried by the relatively coarse mesh portion which is of sucient area to project slightly beyond-the margin of the marking element. With this construction when the device is brou ht down against the soft and Wet 'pulp '.durlng its rotation, the air and Water of the pulp may pass through the Wire mesh to the inner face of the roll quite readily so that no lateral motion of the Water and air from 'member being off'r about the mar in of said element and elseweones the lsplash ellect taking the pulp there with is produced. Likewise as the element rises from the surface of the pulp the air and Water may passl down readily about the f margins of the marking element through the roll sojthat the suction effect as'heretofore described is relieved. lt is therefore possible With this construction to `run the paper machine much faster than has heretofore beeny possible Where Watermarking by the use of a dandy watermarking roll has been desired. j

' Having thus described certain embodiments of this invention it should be evident that various Achanges and modifications might be made thereinwitho'ut departing from its spirit or scope as defined by the appended claims.

I claim:

. .1. A dandy roll having a reticulated surytace, and a Watermarking element' xed thereto, the reticulations of said surface adjacent tosaid element being of larger surface. f

21'A dandy roll having reticulated surface portions of larger 'and smaller mesh, and Watermarking elements fixed to the por-` tions of larger mesh.

3. A dan y roll having asurface portion of Wire mesh, and a Watermarking element fixed to said surface, certain of the Wires ofsaid mesh being removed adjacent to said element to provide openings through the mesh about the margin of said element of 'larger size than through the remainder of said mesh.

4. A device .of the class described comprising a reticulated member engageable with Wet pulp as sheeted on a paper machine, landa Watermarkin element xed to said member and arrange to be periodically impressed on the ulp, saidy reticulated eiativelycoarse mesh fine mesh.

where of relativel hereof ll have aiiixed my ln testimony vv signature.

GEORGE W. VERW.

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