US3252853A - Cylindrical former type papermaking machine and method of operation - Google Patents

Description

y 1966 s. G. HOLT ETAL 3,252,853

CYLINDRICAL FORMER TYPE PAPERMAKING MACHINE AND METHOD OF OPERATION Filed Nov. 16. 1960 5 Sheets-Sheet 1 HTER OUT i !l\l VENTORS SHERWOOD G. HOLT JOHN R. CURTIS Y Que-kw. 47 1,

AT, RNEY a May 24, 1966 s. G. HOLT ETAL CYLINDRICAL FORMER TYPE PAPERMAKING MACHINE AND METHOD OF OPERATION I5 Sheets-Sheet 2 Filed Nov. 16, 1960 INVENTORS SHERWOOD G.HOLT

JOHN R. CURTIS vuofld' ATTORNEY May 24, 1966 s. G. HOLT ETAL CYLINDRICAL FORMER TYPE PAPERMAKING MACHINE AND METHOD OF OPERATION 5 SheetsSheet 5 Filed Nov. 16. 1960 s 1 mf m w z w VP. R mm A0 M 5H r Hw A 5 mm i m q mu which may be in excess of 2500 feet per minute.

United States Patent 3 252 853 CYLINDRICAL FORMER TYPE PAPERMAKING MACHINE AND METHOD OF OPERATION Sherwood G. Holt, Wisconsin Rapids, Wis., and John R.

Curtis, Springfield, Pa., assignors to Scott Paper Company, Chester, Pa., a corporation of Pennsylvania Filed Nov. 16, 1960, Ser. No. 69,668 4 Claims. (Cl. 162-212) The present invention relates to apparatus and process for forming webs of fibers, and particularly to papermaking apparatus and process wherein vacuum controls are operated in conjunction with gravitational and centrifugal forces to remove the water from the stock, so that the machine may be operated at relatively high speeds.

In order more fully to comprehend the unique aspects of the present invention, a few of the characteristics of prior papermaking equipment will be considered, including a brief review of early papermaking methods.

The art and science of papermaking as known today carry the accumulated techniques and traditions of some 2,000 years. It was approximately 105 AD. when the present technique of macerating a product to produce a fibrous pulp in a water solution was developed, with the subsequent removal or drainage of water from the slurry to produce a mass of fibers which were dried into a sheet. The same principle isstill applied inthe making of paper, the fibers of the cellulose stock are dispersed in a water solution, then laid in a thin slurry on a screen, with subsequent drainage of the water through the screen to leave the mat of fibers on the top thereof. The wet web is then couched from the wire and further dried.

During the 1700s wood fibers first were-used as raw material for paper. However, efficient equipment to use the wood fibers first appeared in the mid-1800s with the development of the Hollander (or beater) and the Fourdrinier. Significantly it was the Fourdrinier, replacing the old mold screen to filter the water away from the fibers, which permitted a continuous papermaking process instead of a batch system. About the same time that the Fourdinier was developed in Europe, a cylinder-type paper machine was invented in Germantown, Pennsylvania. In the cylinder process a rotating screen-covered cylinder was partially submerged in a vat of water, and as the cylinder turned, its screen picked up pulp from the vat, forming a paper web which was later pressed and dried.

The principle of the present invention which distinguishes it from the prior art is as follows. The slurry is deposited on a web-forming wire disposed around a cylindrical shell and most of the water is immediately with drawn by vacuum from the slurry to chambers in the shell and immediately thereafter the wet web is couched from the wire and water stored in the chambers is discharged back through the very same wire on which the sheet was formed. The deposit of slurry, the removal of Water therefrom, the couching of the sheet from the wire, and the discharge. of the water all take place while the forming roll rotates less than 90 and at linear speeds Such procedure is clearly distinguishable from the old-cylinder operation as well as from the usual Fourdinier operation with its long, horizontal wire travel from breast roll to couch roll.

With the foregoing in mind, one object of the present invention is to provide a simplified short, compact paper- Patented May 24, 1966 Another object of the present invention is to provide a web forming machine having a wire-covered forming roll for forming webs from a slurry of fibers and water wherein water removed from the slurry is discharged back through the Wire cover.

Another object of the present invention is to provide a papermaking machine with a substantially self-cleaning forming roll having a rigid forming surface.

Another object of the present invention is to provide a papermaking machine capable ofmaking a variety of weights and grades of paper and constructed so that a minimum of changes are required in the machine when switching from one weight or grade of paper to another weight or grade of paper.

Further objects will be apparent by reference to the following specification, claims, and drawings.

With the foregoing considerations in mind the present invention can be more fully understood by reference to the attached drawings wherein like reference characters indicate like parts.

FIGURE 1 represents a side elevational view of a machine made in accordancewith the present invention, partly in section, showing particularly the compact arrangement of the forming roll, slice, pickup, and drier.

FIGURE 2 represents a vertical cross-sectional view of the stock distribution chamber, inlet, slice, and forming roll showing the path taken by the water as it passes from the slice into and back out of the forming roll, as well as the formation of the web between the slice and the pickup.

FIGURE 3 is a fragmentary and elevational view of the forming roll and support therefor showing the apparatus for adjusting the position of the suction box within the forming roll beneath the slice and pickup.

FIGURE 4 is a longitudinal cross-sectional view of the forming roll taken generally along line 44 of FIG- URE 2.

For the purpose of describing the invention, the following description is directed to the preferred means of forming a paper web, but it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the formation of a paper web or to the precise arrangements and organizations of the instrumentalities as herein shown and described.

In the presentinvention there is provided a papermaking machine unique in the industry because of its small size, high speed of operation, great versatility and accuracy of control with regard to the products it makes and high efficiency of operation, all of which result from the unique structure and method of operation. The forming roll which is the heart of the present invention provides the great advantage of simplicity and compactness on the one hand and, on the other, speeds of operation equal to or in excess of the highest presently known to the industry. The machine of the present invention does not require the long Fourdrinier section or cumbersome and expensive wire nor the great mass of castings, supports, guide rolls, drives, controls, and other equipment previously demanded for Fourdrinier machines of the high speed type presently in use. Additionally, it is not restricted to slow speeds and other limitations of conventional cylinder machines. The machine is capable of operating in excess of 2500 feet per minute and of providing webs with carefully controllable variations in ratio of cross mixture and machine direction tensile strength and with a high degree of operating accuracy and the paper is set on a forming roll and removed by a pickup felt before the forming roll has rotated from the application of the slurry to the roll. Because of the unique structure of the machine of the present invention and the fine degree of accuracy with which it can be regulated and the resulting niceties of control afforded the operator, sufficient water can be removed from the paper web before it leaves the forming roll so that the paper web can be removed from the forming roll by a simple pickup felt or transfer device. Completion of moisture removal from the web may then be performed in a much less complicated dryer section. Thus, the entire apparatus from headbox to reel is simplified and hence the capital investment required to produce the equipment, and the operating costs thereof, have been drastically reduced. 'The economy of operation carries over to the supporting equipment and indeed to the building in which the device is installed. The net result is a saving in costs to the user not only at the design stage but through the construction, installation, and operations thereof all of which provide a better web made at faster speeds at less cost.

With the foregoing in mind, the forming roll 21 is supported on bearings 22 and driven through a drive gear 23. The bearings 22 are supported ona shaft 24 which is mounted at each end in a bearing block 25. Each bearing block rests on an arm 26 which is pivoted as at 27 through a suitable screw jack 28 to permit the forming roll 21 to move about the pivot 27 and hence relative to the slice 29, pickup 30 and deflector 31.

The forming roll 21 includes a hollow cylindrical shell 32, which has a multitude of holes 33 extending radially therethrough. On the surface of the shell there is provided an openwork for the reception of fluid. This openwork surface may be provided by counter-sinking the holes 33 to afford a more open surface, or by mounting axially extending fins 34 on the shell with a circumferential winding tape or tapes 35 resting on the fins 34. The openwork and the holes 33 generally are referred to as a plurality'of receptors or cells 36. The shell 32 is supported at each end by a spider or head 37 upon the bearings 22. The shaft 24 extends through the bearings 22 and it supports thereon and becomes a part of the suction box 38 which will be described more fully hereinafter. However, the suction box 38 and shaft 24 are adjustable arcuately within the shell 32 and thus may be nicely positioned between the lower slice lip 46 and pickup 30.

The winding tapes 35 support a backing wire 39 which is tautly drawn around the tapes as shown in FIG- URE 2. A forming wire 40 is woven of diagonally disposed wires to permit its being tightly drawn from end to end about the roll 21 and over the backing wire 39 by suitable clamps 41 so as to provide a taut, rigid surface above the cells 36 on which to form the web. Thus in operation the wire 40 presents a rigid non-yielding forming surface traveling beneath the slice 29. The forming roll may be moved by the pivot arms 26 so that the relative position of slice and wire surface may be carefully controlled.

The suction box 38 is arcuately adjustable within the forming roll, with respect to the slice and the pickup, by the worm gear 42 which controls the angular position of the shaft 24 in the bearing blocks 25. The suction box may have one relatively large chamber 43 or may have a plurality of separate smaller chambers (not shown). The suction box is disposed directly within the shell 32 with the edges 44 of the box in sliding contact with the inner surface of the shell 32 so that the vacuum in the chamber 43 may be transmitted directly to the cells 36 through the holes 33, thus to draw the water from the slurry or stock through the forming wire 40 and backing wire 39 into the cells 36. The web of paper 45 is thus formed within a few inches on the moving forming wire between the bottom lip 46 of the slice 29 and the pickup 30, and the web is transferred to the pickup 30 while water is still contained in the cells 36. Immediately after the transfer of the web from the forming wire to the under side of the pickup felt 47, the fprce imposed on the water by the suction box 38 (which force retains the water within the cells 36) is released and the water is discharged outwardly from the cells 36 by centrifugal force, through the backing wire and forming wire, beneath and away from the horizontal run of the pickup felt 47 and against the deflector pan 48. The transfer to the pickup takes place substantially simultaneously with the breaking of the vacuum holding the water in the receptors of the forming roll and such close control permits the release of water and transfer of web without the danger of disrupting the web by the released water. During the operation just described some water may be drawn into the suction box 38. Unlike any machine heretofore used or disclosed, water is not'only thrown back out of the retaining cells or receptors and backing wire but back through that same fine mesh wire on which the sheet was formed. The construction and operation of the forming roll eliminates any run or travel of Fourdrinier wire while yet differing from any cylinder machine (where the water drawn through the forming wire passes into the cylinder and is removed therefrom through the journals connected to the interior of the roll) in that water is ejected back through fine mesh forming wire of the forming roll. While advantages of the present invention may be realized when as little as 10% of the water withdrawn from the slurry is discharged back out through the wire, advantageously at least 50% of the withdrawn water is so. discharged. With high speed operation, where the present invention is particularly applicable, it is preferred that at least about for example between 80 and of the water withdrawn from the slurry is discharged back out through the wire.

The pickup 30 may include a roll 49 around which the felt 47 is passed, which urges the felt into cont-act with the top side of the web of paper 45 formed on the surface of the forming wire 40. This single pickup felt 47 has a horizontal run 50 and carries the web around a pressure roll 51, which transfers the -web to the surface of the Yankee dryer 52. The felt travels around a turning roll 53 and a second pressure roll 54 and thereafter around suitable turning rolls 55 and stretch roll 56 back to the pickup roll 49.

The slice 29 is supported on a frame 57 which rigidly holds the upper lip 58 and the bottom lip 46 in position with respect to the forming wire 40. However, the outer edge of the top lip 58 may be adjusted toward and away from the forming wire by screws 60 or other suitable mounting devices so that the clearance between the outer edge of the top lip may be nicely adjusted with respect to the forming roll. This control is provided which relieves the operator of usual problems such as wire Wear, wire sag, slice wear, non-uniform slice opening and the like. This arrangement also affords means for duplicating machine performance even though a change of the forming wire may become necessary inasmuch as the operator has a rigid forming surface against which to calibrate his slice lip position. Not even in a Fourdrinier with a tight wire has such control been possible for centrifugal force has always tended to throw the usual traveling wire toward the slice, and as Wear occured the old wire became slack and caused trouble. No such problem exists in the present machine wherein the forming wire is always kept taut over the roll (because of its diagonal wire weave construct-ion) by the clamps 41. The stock is fed to the slice 29 through a distribution box 61 to produce a uniform flow of slurry across the width of the machine and thus provide a uniform sheet across the width of the machine. The stock is led to the distribution box 61 through piping 62.

Preferably the stock is deposited gently against the forming wire so as not forcibly to entangle the fibers in the wire, and the details of a slice which permits this careful deposition of the stock on the wire is more fully shown in US. Patent application, Serial No. 642,239.

As can be seen particularly in FIGURE 1 the deflector pan 48 extends around the forming roll to a point directly beneath the horizontal run 50 of the pickup felt 47 at a point where the tip 63 is disposed closely adjacent the newly formed web of paper on the underside of the felt 47 so as to direct the water into the pit beneath the machine. The position at which stream of water is released is so accurately controlled by the vacuum box 38 and the cells 36 that substantially all of the water discharged is in a stream which makes a noticeably discernable angle with the horizontal run 50 of the felt between the pickup roll 49 and press roll 51.

It is to be noted here that the formation of the web takes place very rapidly. The surface of the forming wire (which may travel in excess of 2500 feet per minute) receives the stock at the slice 29 and the water is removed between the edge of the bottom lip 46 and a line drawn between the center of the pickup roll 49 and the center of the forming roll 21.

The apparatus of this invention can form a sheet of 14 pound paper 90 inches wide at a speed in excess of 2500 feet per minute with the stock fed at a rate of approximately 5000 gallons per minute. Furthermore, the apparatus, with its accurate control enables the operator to swing his machine from one weight and grade of paper to other weights and grades with great ease.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having described our invention what we claim as new and desire to protect by Letters Patent is the following:

1. In a machine for forming a web from a slurry of water and fibers, a rotatable web-forming roll comprising a hollow cylindrical shell having a plurality of receptors therein communicating with the outer periphery of the shell and with the interior of the shell, and a web-forming wire disposed on and completely encircling the periphery of the shell outwardly of the receptors; a slice having top and bottom lips to convey the slurry to the outer surface of the forming wire; a pickup adjacent the wire beyond the slice to remove the Web from the wire; vacuum means within the shell between said bottom slice lip and said ,pickup to Withdraw Water from the slurry through the wire into the receptors thus forming a web of fibers on the wire and to hold water in said receptors, said vacuum means being constructed and arranged to release the water in said receptors to permit that water to move outwardly through the forming wire under centrifugal force after the web has been removed from the wire.

2. -In a machine for forming a web from a slurry of water and fibers, a rotatable web-forming roll comprising a hollow cylindrical shell having a plurality of receptors therein communicating with the outer periphery of the shell and with the interior of the shell, and a web-forming wire disposed on and completely encircling the periphery of the shell outwardly of the receptors; a slice having top and bottom lips to convey the slurry to the outer surface of the forming wire; a pickup adjacent the wire beyond the slice to remove the web from the wire; vacuum means within the shell between said bottom slice lip and said pickup to withdraw water from the slurry through the Wire into the receptors thus forming a Web of fibers on the wire, said vacuum means imposing a vacuum inwardly of said shell sufficient to draw water from said slurry into the receptors of the shell but insufiicient to draw a substantial portion of said withdrawn water through said receptors, whereby the said substantial portion of water in said receptors is permitted to move back through said forming wire as the shell moves beyond said vacuum means.

3. The process of forming a web of fibers which comprises conveying a slurry of fibers and water to a rotating cylindrical screen, withdrawing by vacuum water from the slurry through the screen to form a web of fibers on the screen, retaining a portion of said withdrawn water in a zone underlying said screen by said vacuum in conjunction with centrifugal force, removing the web from the screen and terminating said vacuum where the web leaves the screen thereby releasing water outwardly back through the screen after removal of the web therefrom.

4. The method of operating a paper-making machine having a rotating cylindrical forming screen, which comprises conveying a slurry of fibers and water to said screen, withdrawing by vacuum water from the slurry through the screen to form a web of fibers on the screen, retaining at least a portion of said withdrawn water in a zone underlying said screen for movement with the screen, removing the web from the screen and releasing said retained Water to flow outwardly under centrifugal force back through the screen after removal of the web from the screen.

References Cited by the Examiner UNITED STATES PATENTS 1,867,588 7/1932 Parker J. 162-321 1,870,971 8/1932 Sunstrorn et a1 162-335 2,154,719 4/1939 Berry 162-311 2,193,006 3/ 1940 Kufferath 162-357 2,418,600 4/1947 Ostertag et al. 162-217 2,658,429 11/1953 Malkin 162-321 2,658,430 11/1953 Stevens 162-317 2,943,678 7/ 1960 Fasoli 162-321 2,991,218 7/ 1961 Ci-rrito et a1. 162-318 FOREIGN PATENTS 226,616 1/ 1960 Australia. 528,352 6/ 1931 Germany.

OTHER REFERENCES Brit: Handbook of Pulp and Paper Technology, Rheinhold Pub. Corp, pp. 354, 355, 1964.

Higham: A Handbook of Papenmalcing, Oxford Univ. Press, London 1963.

Labarre: Dictionary and Encyclopedia of Paper and Papermaking Terms, Sevets and Zeitlinger, Amsterdam 1952.

Pulp and Paper Bibliography Manufacture Bibliography and United States Patents 1963, published by the Technical Association of the Pulp and Paper Industry, 1964.

DONALL H. SYLVESTER, Primary Examiner.

RICHARD D. NEVIUS, Examiner.

Claims (2)

1. IN A MACHINE FOR FORMING A WEB FROM A SLURRY OF WATER AND FIBERS, A ROTATABLE WEB-FORMING ROLL COMPRISING A HOLLOW CYLINDRICAL SHELL HAVING A PLURALITY OF RECEPTORS THEREIN COMMUNICATING WITH THE OUTER PERIPHERY OF THE SHELL AND WITH THE INTERIOR OF THE SHELL, AND A WEB-FORMING WIRE DISPOSED ON AND COMPLETELY ENCIRCLING THE PERIPHERY OF THE SHELL OUTWARDLY OF THE RECEPTORS; A SLICE HAVING TOP AND BOTTOM LIPS TO CONVEY THE SLURRY TO THE OUTER SURFACE OF THE FORMING WIRE; A PICKUP ADJACENT THE WIRE BEYOND THE SLICE TO REMOVE THE WEB FROM THE WIRE; VACUUM MEANS WITHIN THE SHELL BETWEEN SAID BOTTOM SLICE LIP AND SAID PICKUP TO WITHDRAW WATER FROM THE SLURRY THROUGH THE WIRE INTO RECEPTORS THUS FORMING A WEB OF FIBERS ON THE WIRE AND TO HOLD WATER IN SAID RECEPTORS, SAID VACUUM MEANS BEING CONSTRUCTURED AND ARRANGED TO RELEASE THE WATER IN SAID RECEPTORS TO PERMIT THAT WATER TO MOVE OUTWARDLY THROUGH THE FORMING WIRE UNDER CENTRIFUGAL FORCE AFTER THE WEB HAS BEEN REMOVED FROM THE WIRE.

4. THE METHOD OF OPERATING A PAPER-MAKING MACHINE HAVING A ROTATING CYLINDRICAL FORMING SCREEN, WHICH COMPRISES CONVEYING A SLURRY OF FIBERS AND WATER TO SAID SCREEN, WITHDRAWING BY VACUUM WATER FROM THE SLURRY THROUGH THE SCREEN TO FORM A WEB OF FIBERS ON THE SCREEN, RETAINING AT LEAST A PORTION OF SAID WITHDRAW WATER IN A ZONE UNDERLYING SAID SCREEN FOR MOVEMENT WITH THE SCREEN, REMOVING THE WEB FROM THE SCREEN AND RELEASING SAID RETAINED WATER TO FLOW OUTWARDLY UNDER CENTRIFUGAL FORCE BACK THROUGH THE SCREEN AFTER REMOVAL OF THE WEB FROM THE SCREEN.

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