US1833910A - Method of and apparatus for paper making - Google Patents

Description

Dec. 1, 1931 P E 1,833,910

METHOD OF "AND APPARATUS FOR PAPER MAKING Filed Ma'rch 29, 1950 6 Sheets-Sheet 1 (fizz/Mir 039M072 W152? 6 She ets-Sheet,

Filed March 29. 1930 Dec. 1, 1931. H. PARKER METHOD OF AND APPARATUS FOR PAPER MAKING 6 Sheets-Sheet 5 Inuuuuun L.

nun-unann- Dec. 1, 1931. H. PARKER METHOD OF AND APPARATUS FOR PAPER MAKING 6 Sheets-Sheei Aw Filed March 2 9. 1950 v RN \\\\\Q h NW2.

Dec. 1, 1931. H. PARKER METHOD OF AND APPARATUS FOR PAPER MAKING Filed March 29, 19750 6 Sheets-Sheet 5 Fllllillllllllllll .Illlllllllll.

Dec. 1, 1931. H. PARKER I METHOD OF AND APPARATUS FOR PAPER MAKING Filed March 29, 1930 6 Sheets-Sheet e Patented Dec. 1, 1931.

UNITED STATES PATENT OFFICE HOWARD PARKER, OF BERLIN, NEW HAMPSHIRE, ASSIGNOR TO BROWN COMPANY, OF

BERLIN, NEW HAMPSHIRE, A CORPORATION OF MAINE METHOD OF AND APPARATUS FOR PAPER MAKING Application filed Harch 29, 1930. Serial No. 439,984.

This invention relates to improvements in paper making machinery of the type WhlCh employs one or more cylinder molds for the formation of the pulp sheet. While most of the individual improved features are applicable to machines having a single cylinder mold, they are hereinafter descrlbed and are illustrated on the drawings as embodied in a multi-ply paper making machine. It is ordinarily desirable to produce paper having the maximum strength and uniformity obtainable with the kind and-quantity of pulp employed. The strength of a sheet of paper depends to a large extent upon the arrangement and the interfelting of the pulp fibers of which it is composed. The uniformity of the sheet depends on the proper distribution of the fibers therein. A further desirable feature in paper for most uses is substantially equal strength in all directions. A sheet of paper made in the usual way on a cylinder mold machine is more easily torn lengthwise than across, this being due to a directional effect given to a considerable percentage of the fibers by the motion of the surface of the mold in the pool of pulp from a which the web is formed. Many attempts have been made to overcome the tendency of a cylinder mold to pick up a web with a predominant proportion of fibers lying in the direction of travel of the sheet, but as far as applicant is aware, these attempts have been unsuccessful in producing a practical and eflicient mechanism for the purpose. According to the present inventlon, mechanism is provided which causes the formation of a web on a cylinder mold with the fibers uniformly distributed therein both as to quantity and arrangement, the fibers also being thoroughly interfelted.

In attaining the results desired, use is made of the well known tendency of fibers in an aqueous suspension flowing through a pipe or in a channel to arrange themselves in line with the direction of flow, due to the variation in speed of flow between water adjacent to the surface of the pipe in contact therewith and the middle of the stream. To this end a stream of pulp suspension is caused to flow adjacent to the c linder mold and parallel to the axis thereo so as to arrange a large proportion of the fibers in the stream in a direction parallel with the axis of the mold. Pulp from this stream is deposited on the mold in such away that most of the fibers which have been aligned with the stream parallel to the axis of the mold retain this directional characteristic so that inthepulp web formed on the mold, a considerable proportion of the fibers are disposed transversely with respect to the web. This strengthens the web and the resulting paper sheet against longitudinal tearing.

The strength of paper made according to the invention may also be augmented by forming a number of very thin webs of pulp and then pressing and felting these webs together into a single sheet. Interfelting be-' tween the plies is promoted by bringing the plies together under such conditions that the water in the plies passes through the sheet substantially in one direction only. In the formation of plies for a paper sheet, one or more plies may be made with a predominating number of fibers extending in the lengthwlse direction of the sheet, others of the plies havlng predominating numbers of fibers extendlng transversely. Such sheet may be made uniformly resistant to tearing in any direction.

For uniformity of distribution of pulp in each ply, a specially constructed cylinder mold is provided, this mold being also adapted for use with an internal suction device for a prellminary draining and compacting of the pulp web on the mold. The provision of asuction box within the cylinder mold necessitates the construction of the mold in the form of a hollow cylinder which must. be sufficiently strong to support the wire screen on its surface against the suction, and must also present to the under surface of the wire screen narrow supporting members so as to avoid.

outer faces free from wire marks from the mold. This is accomplished by the manner in which the several plies are transferred from the molds to the sheet. The mechanism Figure 2.

is furthermore provided with various adjustable features by which the characteristics of the several plies may be modified in various ways.

For a more complete understanding of the invention, reference may be had to the description thereof which follows, and to the illustration thereof on the drawings, of which,

Figure 1 is a side elevation of multi-ply paper making mechanism embodying the invention.

Figure 2 is a transverse section of one unit of the mechanism shown in Figure 1, the section being taken on the line 2-2 of Figure 8.

Figure 3 is a section on the line 3'3 of Figure 4 is a fragmentary transverse section of one of the cylinder molds.

Figure 5 is a section of the same.

Figure 6 is a perspective view of avpulp vat.

Figure 7 is a fragmentary longitudinal section of mechanism within a cylinder mold.

Figure 8 is an end elevation of one of the paper making units, part of the figure being a section on the line 8-8 of Figure 1.

Figure 9 is an end elevation of a paper making unit viewed as indicated by the line 99 of Figure 1.

Figures 10 and 11 are sections taken res ectively on the lines 1010 and 11-11 of igure 8.

Referring to the drawings in detail, Figure 1 represents in elevation a portion of a multi-pl paper making machine, three cylinder mol s 20 being shown. The machine may include a larger or smaller number of cylinder molds as desired. The molds 20 are are each supplied with a suitable pulp vat 21, the molds and vats being conveniently supported as by a pair of horizontal beams 22. As shown, the vats 21 are so located as to present the stock therein to an upper quadrant of each of the molds, the pulp web which is picked up by each mold being deposited on a suitable felt 23 which travels in a generally horizontal path beneath the molds and may be tangent to one or more of them. In the mechanism illustrated in Figure 1, the felt 23 is tangent to two of the three cylinder molds 20 but passes underneath the third mold, on theleft hand side of the figure, without touching it, the web from this mold being transferred first to a felt 24 from which it is picked up by the felt 23. This arrangement may be employed when it is desired to produce a sheet'of paper having both of its surfaces smooth. As the pulp is deposited in a Web on' any of the cylinder molds 20, the face of-the web which is against the mold itself'is wire-marked thereby, the opposite fragmentary longitudinal face of the web being smooth. It is obvious from Figure 1 that where the felt 23 is tangent to a mold 20 the web from that mold is deposited on the felt with the wire-marked surface up. By transferring the final ply first to the felt 24 and then to the felt 23, the ply or web is inverted so as to be deposited on the felt 23 with its smooth side up. This produces a paper sheet with both faces smooth.

In forming a multi-ply sheet of paper from a number of thin individual wet plies, it is important to promote maximum interfelting of the fibers in the successive plies if strength is desired in the ultimate product. Relatively great strength may be obtained by uniting the successive plies 1n such a manner that the moisture therein flows through the sheet in a single direction. This draws the fiber ends into effective interfelted rela tion which ties-together the successive plies and produces a strong coherent sheet. In order to bring about such interfelting between the plies, a suitable suction box 25 is provided against the under face of the felt 23 at the point where the felt touches the circumference of the cylinder mold 20 or the felt 24. Thus the passage of the water in the several plies is maintained in a downward direction through the sheet in the process of its formation, this unidirectional flow promoting a high degree of interfelting between the fibers of the successive webs or plies. In order to consolidate the sheet after each ply has been added thereto, a suitable press roll 26 may be provided to press upwardly against the surface of the cylinder mold 20 so that the felt 23 with the pulp sheet thereon is squeezed between the roll 26 and the mold 20. The pressure of the roll 26 against its mold may be regulated as by a system of levers 30, 31 linked together as at 32, the lever 31 having an adjustable weight 33 thereon. Each suction box 25 may be resiliently held adjacent to the surface of a cylinder mold 20 as by a suitable lever 34 which may be pivoted as at 35, one end of the lever engaging a lower face of the box 25 as at, 36, the opposite arm of the lever being provided with an ad'ustable weight 37. The limit of approach 0 the suction box toward the cylinder mold 20 may be conveniently regulated as by a set screw 38. The felt 24,

after picking up the pulp web from the cylin-.

der 20, ma pass around a suitableroll 41 which is a jacent to or in contact with the cylinder 20. In this form of construction the press roll 26 engages the roll 41 rather than the cylinder m'old 20, and the suction box 25 is likewise adjacent to the roll 41. This arrangement results in a transfer of the pulp web from the felt 24 to the felt 23 when the former is passing about the roll 41. The felt 24 may thereupon be led upwardly to a suitable tank 42 where it may be washed as by jets from a spray pipe 43, after which the felt is led back into contact with the cylinder mold 20 by suitable guide rolls.

The pu p vat by which pulp stock is supplied to the surface of each cylinder mold is illustrated in Figures 2, 3 and 6. As shown the pulp may be supplied through a suitable supply pipe 50 into a compartment 51 at one end of the vat. In this compartment it flows downwardly and enters a horizontal channel 52 wherein a considerable body of pulp flows in a direction parallel to the axis 0 the cylinder m'old, this channel extending from one end of the mold to the other. The wall 53 of the channel 52 which is nearest tothe' tions 54. The wall 53 is preferably placed about an inch from the surface of the cylinder mold 20, but this distance may be varied as desired. The other end of the channel 52 the apertures 54 is made sufficient to produce opens into an uptake 55 through which the stock fiows into an upper compartment 56 and spills over a dam .57 into a discharge compartment 58 whence it leaves the vat as at 59. The stream of stock flowing through the channel 52 tends to arrange a large proportion of the fibers therein in the direction of flow of the stream, that is, in a direction parallel to the axis of the cylinder mold. As

and-against the surface of the cylinder mold,

where they interfelt with one another to form the web of pulp which is subsequently transferred to the felt 23.

The combined cross sectional area of all a rapid flow of pulp therethrough. The distance of such flow from the channel 52 to the surface of the cylinder mold illustrated in Figure 2 is approximately one inch, so that there is insufficient time for any considerable number of the fibers to turn to dif ferent directions, and a large majority of the fibers are drawn against the surface of the mold in a direction which is substantial- 1y parallel to the axis of the mold, that is, transverse with respect to the web itself. Thus the sheet of pa er formed with plies laid in this manner as a high resistance to longitudinal tearing. If desired, the directional strength characteristics of the fin- .be'1conveniently.adjusted, as by a vertical :movable board 61' which acts as an adjustable crest for the dam 57. The board 61 may be adjustable by any suitable mechanism such as a pair of uprights 62 each having a rack 63 meshing with a pinion 64, the pinions being mounted on a common shaft 65.

In order to control. the characteristics of the pulp webs deposited on the several cylinder molds 20, it is desirable to supply each cylinder mold with internal suction mechanism by which suction may be applied to a suitable arc of the inner surface of the wire screen. Since the cylinder mold must necessarily be rotated, the presence of suction apparatus within the mold necessitates the construction of the mold in the form of a hollow cylinder. As the suction is applied to the upper portion of the cylinder mold, it adds materially to the gravitational stresses on the mold itself so that the mold mustbe strongly made to .avoid sagging in the middle or other distortion under the stresses imposed thereon. The cylinder mold must also be formed with a surface against which the Wire screen may be supported, the supporting surface of the mold being preferably no Wider at any point than approximately one-sixteenth of an inch. If any of the areas of support are materially wider than that, the depositing of pulp on the areas of screen over such portions is retarded so that the thickness of the pulp web is nonuniform. According to the invention a cylinder mold is provided which is not only strong and rigid, but which has, a supporting surface for its Wire screen such that the thickness of the web deposited on the screen is uniform from end to end of the mold. a

As shown in Figures 2, 4 and 8, the cyl' inder mold comprisesa series of rings placed side by side and hold together by a series of tie bolts 71. Each ring consists of a flat portion in a plane perpendicular to the axis of the mold. Extending from one face of this flat ring are a number of vanes 72 and 73, these vanes extending from the inner edge of the ring to the outer edge in a direction which is preferably at an angle to the radial direction. As indicated in Figure 4, the vanes 72 alternate with the vanes 73, the former each having an enlarged portion 74 which is bored to receive a tie-rod 71 therethrough. When the rings 70 are assembled to form a hollow c lindrical shell, the vanes of each are suitably aligned with the corres onding vanes'of the others so that the tie-r0 s 71 extend from end to end of the cylinder through a succession of correspon ing vanes in the, several rings and the corresponding sets of vanes 72'and 73 form substantially continuous partitions extcnding from one end of the mold to the other. Between such successive partitions are channels 75 passing from the outer surface of the cylinder mold to the inside of the mold. The outer surface of the cylinder is covered with the customary screen 80 offine wire. To sup ort this screen smoothly in'the form of a su stantially true cylinder, a series of supporting ribs 81 is provided. As indicated in Figure 5, each of the vanes 72 and 73 is slotted at its outer end to receive the ribs 81, with the outer edges of the ribs flush with the outer edges of the vanes. The ribs 81 ma conveniently be formed by winding helica ly and edgewise a single strip of flat wire around the cylinder mold in successive notches in the vanes, this wire being retained in place by soldering, brazing, or in any convenient manner. The wire 81 is preferably about one-fourth to five-sixteenths. of an inch wide and one-sixteenth of an inch thick, this being suflicient to support the wire "screen 80 without causing any thin places in the web deposited on the screen, as it is wound so as to present one edge outward as indicated in Figure 5.

Suction may be applied to a portion of the mold as by mechanism illustrated in Figures 2 and 8. In the cylindrical chamber within the mold, a suction chamber may be formed by a partition member 90 which extends from one end of the mold to the other and which terminates at one end in a suction pipe 91. This partition may be stiffened by a suitable longitudinal rib 92.- As shown in Figure 2, the partition 90 extends from side to side of the chamber within the mold, the partition contacting with the inner surface of the mold through suitable packing strips 93 against which the inner surface of the mold rubs as the mold rot-ates. Sincethe downward drag on the cylinder produced by the suction is considerable. especially when the cylinder is of considerable length, bearing members may be provided to support the middle portion of the cylinder. These may be in the form of a pair of longitudinally extending ribs 94 which are supported by the partition member 90 and which bear on the inner surface of the mold bv means of packing members 95. It is desirable to be able to regulate the characteristics of the pulp web picked up by the cylinder mold by-rotationally adjusting the partition member 90 about the axis of the cylinder. To this end the suction pipe 91. which is integral with the partition 90 and projects from the end of the cylinder, as shown in Figure 8, is provided with a lever arm 96 which is connected as by a screw 97 to a fixed nut 98 mounted on the frame 22, as shown in Figure 1, so that by manipulation of a hand wheel 99 the lever arm 96 may be the packing angularly adjustable and which is provided 7 with an extension 106 in threaded engagement with a screw 107. The latter may be fixed against axial movement, as by a suitable bearing 108, and may be rotatable by a convenient hand wheel 109 to raise or lower the suction apparatus within the cylinder..

Provision is made for producing pulp webs of di li'ercnt widths by deckle members 115 which are adjustable length-wise of the cylinder mold. When the deckles are moved to change the width of the web to be deposited on the cylinder mold, it is desirable to adjust correspondingly the length of the suction chamber within the cylinder mold. To this end the end walls of the suction chamber are made adjustable as illustrated in Figures 7, 8, 10 and 11. The suction chamber itself extends from one packing strip 93 to the other. In a-segment between these two strips is a plate 116 having a packing 117of resilient material around it, this packingbeing adaptedto fit against the inner surface of the cylinder mold 20 and alsoagainst the upper surface of the partition member 90. As

shown in Figure 7, this plate 116 and the packing 117 are movable longitudinally of the cylinder. For. adjusting movement of the plate 116, it is provided with an extension 118 the end of which is in threaded engagement with a screw 119 which may be rotated by a sprocket wheel 120 to move the plate 116 and packing 117 toward or from the end of the cylinder mold. Since the packing 117 must be loose in order to permit such adjusting movement, means are provided for expanding and contracting the packing. For this purpose the packing is mounted between the plate 116 and an opposing plate 125, these plates being provided with conical surfaces adapted to press against the packing 117 and to cause the packing to bulge outwardly when the plates move toward each other. Such motion may be provided by a tubular member 126 which is internally threaded on a portionof the extension 118, as at 127. The tubular member,126 is in splined engagement with a tubular extension 130, the latter being provided with an operating wheel 131 which may be a hand wheel or a sprocket wheel. The splined engagement of the tubular memher 126, with its extension 130, permits these two members to telescope when the plate 116 is drawn outwardly toward the end of the cylinder mold. A key or spline 132, mounted in the tubular member 126, slides in a suitable slot 133. \Vhen it is desired to move the plate 116 and the packing 117 in accordance with an adjustment of the corresponding deckle 115, the wheel 131 is rotated to move the plate 125 away from the plate 116 and thus to permit the packing 117 to contract away from the cylinder mold. Thereupon the wheel 120 is rotated in a direction suitable to move the plate 116 to the desired location, whereupon the wheel 131 is operated in a reverse direction to expand the packing memher 117 into contact withthe cylinder mold 20. The sprocket wheels 120 and 131- may be suitably connected by chains. (not shown) to other hand-operable wheels more conveniently located.

The characteristics of the pulp 'web deposited on the cylinder mold may further be controlled by the provision of a mask 140 (Figure 2). This may be in the form of a waterproof sheet, one end of which is wound on a; suitable roll 141, the free end portion passing under a guide block 142 and resting against the surface of the cylinder mold 20. By raising or lowering the free end, the area of loading surface of the cylinder mold may thus be regulated.

In the lower portion of the pulp vat 21, a separate compartment 145 may be provided, this compartment containin a spray p1pe 146 adapted to project jets o washing water against the surface of the cylindrical mold in order to clean the wire screen just before it is exposed to the pool of pulp stock within the vat. A suitable apron 147 may be provided to catch the pulp which is thus washed from the surface of the screen. The wash water which is projected through the screen and through the cylinder shell may be caught in a suitable compartment 150 within the mold, from which it may be led away by suitable channels. In the lower portion of the chamber within the cylinder mold a suitable arcuate plate 151 may be provided to catch white water which may flow through the mold from the vat before the material comes in contact with the first packing member 93. Thus the. mechanism. may be adjusted so as to cause the pulp to be depositedquickly on the mold under the action of gravity alone. This results in an even, well distributed sheet and avoids wild. webs. After the initial depositing of pulp on the mold, suction is applied while the web is still in 'contact with the pool of pulp stock. This suction condenses the deposited web and also tends to thicken any adventitious thin spots. The suction is maintained transfer to the felt 23.

from until the mold reaches the second packfrom suction until it reaches the point of I claim: 1.111 the art of paper making, a method of supplying pulp stock to a rotating cylinder mold, which comprises inducing a freeflow of stock in a stream adjacent to the cylinder mold and parallel to the axis there of, shielding said stream from disturbance by the motion of the mold, and drawin stock laterally to the surface of the mol from adjacent points of the stream.

2. In the art of paper making, a'method of forming a. pulp web on a rotatingcylinder mold, which comprisesinducing a free flow of pulp stock in a stream adjacent to the mold and parallel to the axis thereof, shielding said stream from disturbance by motion of the mold, drawing stock laterally 111g member 93, whereupon the web isfreed from the stream to a portion of the surface of the mold adjacent thereto, maintaining a body 'of pulp stock against the next adjacent portion of the mold surface in the direction of its motion, and applying suction within the surface portion of the mold in contact with said body of pulp.

3. Apparatus of the class described comprising a cylinder mold, a pulp stock vat adjacent to said mold, and a duct for pulp stock within said vat extending substantially parallel to the axis of said mold, said duct having a perforated side-wall close to a portion of the surface of the mold, said vat having supply and discharge passages communieating with the ends of said duct whereby a stream of stock may flow longitudinally through the duct.

4. Apparatus of the class described comprising a cylinder mold, a pulp stock vat adjacent to an upper quadrant of said mold, and a duct in said vat extending substantially mrallel to the axis of said mold, said duct having an arcuate perforated side wall following the. shape of the adjacent surface of the mold and spaced about an inch therefrom, said vat including means for maintaining a pool at a substantially constant level above said duct and communicating with one end thereof whereby a regulated fluid pressure is maintained in the duct.

5. Apparatus of the class described comprising a cylinder mold, a pulp sto' k vat against a portion of said mold, a perforated curved plate within said vat and spaced a short substantially uniform distance from the adjacent surface of the mold, and means within said vat for directing a flow of pulp along theface of said plate remote from the mold in a direction substantially parallel to the axis of the mold.

6. Apparatus of the class described comprising a cylinder mold, a pulp stock vat against a portion of said mold adapted to present a pool of stock to a portion of the surface of the mold a curved plate in said vat uniformly spaced from the adjacent surface of the mold, said plate extending above the normal surface level of said pool of-stock and having perforations through the lower portion thereof, and means including said vat for maintaining a flow of stock along the perforated portion of said plate on the side remote from the mold and in a direction parallel to the axis of the mold.

7. Apparatus of the class described comprising a cylinder mold, a pulp stock vat I against a portion of said mold adapted to present a pool of stock to a portion of the surface of the mold, a curved plate in said vat uniformly spaced from the adjacent sur- 7 face of the mold, said plate extending above the normal surface level of said pool of stock and having perforations through the lower portion thereof, means for maintainin a flow of stock along the perforated portlon of said plate on the side remote from the mold and in a direction parallel to the axis of the mold, and an adjustable flexible shield extending upwardly from the bottom of said vat adjacent .the surface of the mold.

8. Apparatus of the class described comprising a cylinder mold, a pulp stock vat against'a portion of said mold adapted to present a pool of stock to a portion of the surface of the mold, a curved plate in said vat uniformly spaced from the adjacent surface 7 of the mold, said plate extending above the normal surface level of said pool of stock and having perforations through the'lower por- I tion thereof, means for maintaining a flow of stock along the perforated portion of said plate on the side remote from the mold and in a direction parallel to the axis of the mold, and means for applying suction from within to a portion of the surface of the mold extending from below the surface of said pool of stock to a point beyond the point of emergence of the mold surface from said pool. I

9. Apparatus for making multi-ply paper, which comprises a plurality of cylinder molds in a series, a'pulp stock vat against an upper quadrant of each said mold, a traveling felt disposed beneath said molds and tangent to at least the first of said series of molds to receive directly therefrom the web of pulp formed thereon, an auxiliary felt in quadrant of each said mold, a felt trave to the mold up, and means for transferring the web on the last of said molds in the series to said felt with the face of the web formed next to the mold down.

In testimony whereof I have aflixed my signature.

H'OWARD PARKER.

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