US3205126A - Paper making machine - Google Patents

Description

Sept. 7, 1965 G. E. CLINK 3,205,126

PAPER MAKING MACHINE Filed Feb. 8, 1962 3 Sheets-Sheet l VEN TOR. GEO E. CLINK BY g ATTORNEY Sept. 7, 1965 ca. E. CLINK PAPER MAKING MACHINE 3 Sheets-Sheet 2 Filed Feb. 8, 1962 INVENTOR.

GEORGE E. CLINK A TTORNE Y.

Sept. 7, 1965 G. E. CLINK ,2

PAPER MAKING MACHINE Filed Feb. 8, 1962 s Sheets-She et 5 INVENTOR.

GEORGE E. CLINK BY fig ATTORNEY.

I I I United States Patent 3,205,126 PAPER MAKING MAC George E. Clink, Glens Falls, N.Y., assignor to The Sandy Hill Iron & Brass Works, Hudson Falls, N.Y., a corporation Filed Feb. 8, 1962, Ser. No. 171,938 2 Claims. ((31. 162-817) The present invention relates to structural refinements in a paper forming machine and more particularly to improved means in a variable stock inlet or headbox or stock delivery mechanism for controlling the flow of an aqueous suspension of papermaking fibers to, and its deposition upon, a web forming surface of a looped face wire entrained around a rotating foraminous cylindrical shell, and in a means for depositing the formed felted web upon a pickup felt running over or adjacent the top of said shell, with the obvious advantages that the web is permitted to be formed upon the face wire and subsequently dried by a suction means disposed within the shell and thereafter picked up from the face wire by the pickup felt.

By the entrainment of the face wire around the shell, it acts as a backing for the formed sheet so that same may be lifted from the arcuate surface of the shell by means of the wire, even though there may be a vacuum under the wire at the point of separation of wire and shell and the formed sheet may be then carried tangentially away from the shell to a distant transfer point.

The arrangement of elements herein permits a leakage of air into the vacuum means within the shell wherefor the problem of water roll-out is controlled to a degree where throw ofi is eliminated or at least the throw off is at a point sufficiently beyond the point of separation of shell and wire and in a direction away from the direction of travel of the wire so as not deleteriously to affect sheet formation.

By taking the face wire off of the shell and entraining it around another roll, the recognized tendency of a shell, without such a face wire, to carry water entrapped within its openings so that same cannot be released therefrom (due to the fact that no air can creep in so as to allow it to be released) is herein obviated.

In such shells without the accompanying face wire, no trouble is experienced at the slower speeds, as it is possible, at such speeds, to evacuate the shell openings. However, with higher operating speeds, the water is not released and the formed sheet accordingly has to be released by vacuum means.

In the present invention, it is possible to remove the formed sheet via the face wire because it has the strength at the moment of leaving the shell periphery to withstand the slight amount of vacuum experienced thereat. In essence, the face wire is lifted off and away from the vacuum box to a slight or minute degree before the farther end of the vacuum box is reached wherefor a small amount of free air is bled into the box and beneath the formed sheet.

The embodiment may be described as a machine capable of handling stock of higher densities and feed velocities than is possible with conventional types of papermaking machines, which lends itself to the use of improved means for controlling the flow and distribution of the stock delivered to the face wire forming surface, and an improved type of forming surface. Too, it provides a simple, inexpensive control means for compensating for variations in stock feed and gas feed into or vacuum pull on the stock chamber, and allows the maintenance of a constant pressure upon, and a constant level of the stock in, the stock chamber, irrespective of changes in stock feed conditions.

One primary reason why a more level sheet is produceable herewith is because of the fact that the water drainage is radially of the sheet formation area and equally across the machine width and further because there are normally air pockets at the tops of the suction means which can be and are herein employed advantageously.

The paper forming machine hereof possesses the characteristics of both the Fourdrinier and the cylinder types of paper forming machines and will be composed of: 1, a stock-receiving component or pond and an associated flow distributor, or fish-tail flow spreader, for bringing the stock from a supply inlet or inlets in a uniform consistency flow across the machine width; 2, a sheet-forming component including a peripherally-supported hollow, spokeless shell or cylinder, having a foraminous outer surface, rotatable on a horizontal axis, and having a multiplicity of suction boxes disposed therewithin, and a face wire entrained around the shell and around a turning roll, and 3, a take-off component including a pickup roll.

The stock-receiving component comprehends means for maintaining a predetermined flow rate by a system of pressured stock and/or pressured air and functions as a surge chamber for storing the stock before delivery to the forming area so as to absorb any slight pulsations or variations in the stock, to level out any stock irregularities, and to preclude creation of a quiescent pond which will permit fiber flocculation or fiber settlement.

The pond, if desired, may be sealed by a membranous means which is so flexible as to allow adjustments of the pond regulator, while simultaneously allowing a pressure buildup therewithin.

The stock-receiving component will include a pressure inlet means or approach passage to deliver stock to the forming area of the wire in a quantity which is normally, but not necessarily, in excess of that adequate for sheet formation, with the excess being recirculated through suitable means for subsequent reuse, and will also include a connecting flow spreader which may be of any desired design for spreading a flow across the machine width. The connecting approach passage will define the pond to receive stock from the flow spreader and disperse it through a mouth or discharge orifice extending laterally across the machine width adjacent the upper quadrant of the shell with the lower forward wall of said mouth offering a leading edge extending parallel to the shell axis and functioning as a slice plate over which the stock flows to the face wire surface.

The lower and forward wall of an adjustable pond regulator disposed within the pond will coact with the lower forward wall of the mouth in manner to attain minute changes in the approach passage dimensions immediately prior to and during stock formation on the face wire circumadjacent the upper ascending sheet forming quadrant of the shell.

The pond regulator will be an adjustable member disposed within the pond and movable relative to the walls thereof and to the adjacent shell so that it may be related to the shell in any of a myriad number of positions of angularity, in manner to control the directionand speed of the stock onto the face wire. That is, the cylinderward side of the pond regulator will define, cooperatively with the adjacent shell quadrant, the aforementioned approach passage according to a predetermined configuration in dependence upon the characteristics of the stock, the sheet to be formed, and the speed of operation, so that a reproduceability "of results is easily possible. After judicious experimentation to obtain the best formation of a particular sheet, the precise conditions of operation can be subsequently duplicated to produce the identical results.

Such construction permits an improved control of the velocity of the stock at the forming area, it being well known that, for optimum operating papermaking machines at the high speeds demanded thereof today, the stock must be allowed to flow from the discharge orifice onto the forming area at a requisite velocity, usually attained by maintaining a high head of stock in the pond. As is also known, the velocity of paper stock at the slice is determined by the total pressure head of the stock, which total pressure head is produced by the pressure on the stock plus the head of the stock substantially above the slice. Variations in the head pressure and/or gas pressure upon the stock serve to effect the changes in the flow rate, and accordingly, in the web-forming conditions on the forming surface.

Herewith, pressure within the approach passage may be controlled by adjustments in the location of the pond regulator so as to move same in close proximity to or distantly from the face wire, it being appreciated that, the closer the pond regulator to the forming surface the narrower the discharge, and accordingly, the greater the pressure that might be applied in the forming area. Such pressure induces a greater drainage in the available forming area, wherefore more dilute stocks may be used, and further, wherefore heavier sheets may be made than would be possible without such pressure. Too, the production of a sheet having better profile is made possible, due to the fact that the sheet is formed from a pond, which formation is controllable by the drainage rate of the mat on the face wire rather than by a control of the concentration of the fiber in the slurry.

The sheet-forming component comprehends end frames positioned at opposite ends of the shell for peripherally supporting same for its rotation. The forming portion of the shell per se will be of relatively short circumferential length or of an arc of relatively small angle, as contrasted with conventional cylinder type machines, so as to allow more positive sheet formation and higher speeds of operation. The shell allows a hollow center into which water extraction compartments, open to the inner face of the shell, may be disposed for ready access and movability. Such compartments may be varied in accordance with various factors, such as variations in the nature of the stock for better control of the thickness and formation of the sheet. Each such compartment preferentially, though not obligatorily, includes air extraction and water extraction conduits for the separate withdrawal of air and water therefrom. And in some practical applications of the invention, these compartments may be eliminated and a shallow white water collecting pan substituted therefor.

The take-off component comprehends a pickup roll bearable against the face wire distantly of the peripheral surface of the shell around which a pickup felt will be entrained, said pickup roll being in the form of a plain rubber covered, roll or of a suction pickup roll, with the pickup felt being designed to pick up the formed sheet from the face wire at said pickup roll.

In operation, the stock is supplied as a layer to the web forming region or zone of limited extent defined by that portion of the face wire circumadjacent the shell at its upper ascending quadrant as by forcing same through the approach passage and onto the face wire forming surface, with the layer being caused to drain through the wire and shell, the stock so applied containing the required amount of fiber in an amount of water sufiicient to produce the proper fiber distribution in the formed web. Sufficient water drainage is effected during the time period that the formed web remains on the wire to produce a coherent sheet capable of being couched therefrom.

Lumpy formation is avoided, due to the fact that, after the web is formed, it is not disturbed by being drawn through a pond or slurry and the induced vacuum is such as to preclude any stock slip back.

A couch .roll, controllable by air-loaded cylinders or equivalent means, may be provided, adjacent the shell, for the usual and well known function, if desired.

I am aware of a paucity of suitable instrumentation which has been the stimulus for improvisations in prior art papermaking machines of both the Fourdrinier and cylinder types of purposes of effectuating high speed operation. Until now, no satisfactory construction has been forthcoming which combines in a simple manner the multiplicity of desirable features in such a construction suited for high speed operation.

In the Fourdrinier type of machine, a certain volume of fiber suspension is discharged through the slot between a slice and apron and is deposited upon a generally horizontally-extending wire. It is the general desideratum that this suspension carry the exact same concentration of fiber at every point transversely of the wire. This purpose frequently fails so that heavy and light streaks across the sheet result. With the invention hereof, contrariwise, means is provided to control this uneveness before the stock comes out of the pond, whereby a levelness of a degree heretofore unobtainable is achieved.

The conventional cylinder machine, on the other hand, comprehends a perforate drum rotatable about a horizontal axis and disposed within a vat, with a greater portion of the drum periphery being submerged in the stock. The solid matter is deposited on the drums outer surface and excess liquid from the deposited layer is drawn through the drum by a suction means. There is normally a difficulty in holding the sheet firm wherefore some or all of the original formation is not maintained in its travel through the vat, due to the cylinder being submerged. Too, because of the softness of the sheet being formed, due chiefly to its high water content, it is susceptible of being sloughed off and its formation seriously impaired or disturbed, all disadvantageously limiting operating speeds. In this invention, the vat is dispensed with and the immersion of the cylinder mold in the stock supplied to the vat is precluded and a unique arrangement is substituted therefor which enables thin sheets of excellent formation to be produced from thicker stock than has heretofore been considered feasible, all advantageously affecting production costs by reducing the amount of dilution-water and power required.

To attain satisfactory machine operation, it is desirable to supply the stock to the web-forming region at a pressure capable of producing a delivery velocity at the slice which is approximately equal to the velocity of the traveling forming surface. The two requirements heretofore have been inherently conflicting and notoriously incapable of correlation except at low operating speeds, so that the operation of most papermaking machines has been heretofore conducted under compromise conditions.

To obtain a sufficient gravity head of stock capable of producing a continuous pulp supply at a proper pressure and delivery velocity, headbox constructions of objectionably excessive dimensions to maintain heads of stock of great depths have been necessitated. Such headbox elevation has become a serious matter, particularly in the case of those machines which operate over a wide range of speeds. Too, 2. high pond of stock offers the disadvantage of permitting stagnant areas within the pond, wherefore lumping of the stock is apt to occur, not to mention that unreasonably large space-consuming equipment is necessitated. Because the headbox must be elevated to provide a sufiicient head for the maximum contemplated machine speed, during lower speed operations, objectionable turbulence is encountered with the fall of the fluid to the head or level required to produce the discharge velocity for such lower operating speeds, which turbulence has a detrimental effect on sheet formation.

Herein, I provide means for supplying stock to the discharge or delivery orifice at a desired pressure and velocity, within the aforesaid objectionable elevated headbox.

Pressurized headbox constructions have been heretofore employed with the stock being supplied to an enclosed headbox chamber connected to a source of pressure air whereby a body of pressurized air is maintained in the upper portion of the pending chamber to effectuate a lowering of the stock level therewithin, While maintaining sufiicient pressure to insure adequate spouting velocity at the slice. But this and other pressurized headbox apparatuses, one of which has included a vent in the headbox side wall for automatically maintaining the stock level within the headbox at a predetermined value, have each disclosed operational disabilities, particularly when it has been desired to maintain the height of the stock at a value less than approximately 18 inches. Such has produced conditions of instability, evidenced by the formation at the slice of diflicult-to-control irregularities in the flow pattern.

Herewith, these objectionable features are overcome and increased pressure is allowed to be applied to the mat in the forming area, without a need for corresponding increases in headbox stock depth.

In one form hereof, a means for the maintenance ofreduced pressures, as contrasted with super-atmospheric pressures, is envisioned which will hold a sufficient head of stock in the inlet box to cover rectifier rolls or holey rolls disposed therein, even when a slow slice discharge is preferred, a feature not heretofore attainable with a head of stock high enough to cover the rolls or other instrumentalities.

In an alternative form of the invention, super-atmospheric pressures are comprehended, with the stock inlet having a compressed gas feed to allow the maintenance of the stock at a relatively low level behind the slice without diminishing flow velocity, as compared with the conventional high level of stock behind the slice. Thereby, the pond may be partially filled with stock from the inlet feed and the atmosphere above the stock in the stock chamber may be supplied with a compressed gas, so that stock pond is under super-atmospheric pressure to induce the stock to spout out through the slice onto the forming surface.

Another dominant aim hereof is to teach the use of a pond of slurry located against the face wire so that, as the mat is built up upon the forming surface, resistance to flow increases. Accordingly, if a heavy spot should form, the drainage through such heavy spot is less than the drainage at adjacent light spots. With increased drainage at the light spots, more fiber is deposited upon the wire until the drainage rate through the web across the entire width thereof is rendered more uniform.

As another significant feature hereof, it will be explained that where a perforated shell is employed without a face wire entrained therearound, water may be carried within the shell perforations so that when the formed sheet is moved beyond the last of the suction means, the water is thrown out to effect a rewetting of the formed sheet, weakening same and possibly making it impossible to lift the sheet from the shell as the vacuum may hold it too firmly to the forming surface. The reliable solution of these inherent problems is achieved by the present construction.

These and othe objects and advantages herein characterize the present invention, and distinguish it from previously known devices of a kindred nature.

The physical embodiments here described will be indicative of but two of the multiplicity of ways in and purposes for which the principles of the invention may be employed.

The invention will be better understood from a consideration of the detailed description which follows,

when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of the forming shell and headbox and associated parts of the illustrative machine of the invention;

FIG. 2 is a diagrammatic sectional elevational view of a conventional installation embodying one form of the instant invention and, showing the pressured approach chamber formed between the pond regulator and the wire entrained around the shell; and

FIG. 3 is a view, similar to FIG. 2, illustrating a modified form of the instant invention.

I have shown, in FIG. 1, a papermaking machine constructed in accordance with the teachings of the invention and which includes a pair of vertically-extending transversely-spaced side frames 2 (only one of which is shown) which may be secured as by weldments to sole plates 4 for securement to a foundation.

An annular end ring 8 is fixed to the inside of each said side frame 2' for peripherally supporting the opposite ends of a hollow, spokeless, cylindrical shell 10 disposed in a horizontally-extending manner between the side frames 2.

The shell 10 is rotatable on its horizontal axis and supports a looped face wire 11 entrained therearound and comprises a closely perforated or reticulated cylinder bearing shoe or seat 14.

Each said end ring 8 may be suitably configured with a circumferentially-arranged groove in which the respective shoe 14 may be receivable so as to rotatably support shell 10 about a fixed horizontal axis.

Drive means (not shown) may comprise peripherallyarranged gear teeth secured about the shell at opposite ends thereof for meshing in seriatim with pinions mounted on the respective adjacent frame member, said pinions being power driven by a suitably sourced motor (also not shown) appropriately coupled thereto for effectuating shell rotation. Same does not form a part of the present invention and therefore further detailed description is believed to be unnecessary.

The face wire 11 is an endless travelling member entrained around shell 10 and preferably comprises a wire cloth, similar to the making wire of a Fourdrinier ma chine, so as to offer -a sheet-forming surface which is continuously supplied around at least a portion of shell 10, and it is arranged for coaction'with an endless pickup felt 13 (as may be seen in FIG. 2) which passes between face wire 11 and a pickup roll 15 disposed distantly of the top of said shell, the pressure of said pickup roll on said pickup felt causing the felt to contact face Wire 11 in manner to pick up therefrom the formed web of stock fibers after the face wire has passed through an one side of its vertical axial plane and substantially in aplane with its horizontal axis, on the side thereof where the shell surface is moving upwardly.

The exact form of headbox employed will be variable to meet individual mill requirements, some mills having a basement, and some requiring all appurtenant equip ment to be disposed above the machine room floor.

Headbox 26 is formed by transversely-spaced verticallydisposed side Walls 28 extending rearwardly from opposite ends of shell 10, the arcuate forming surface of shell 10 constituting the so-called upper forward wall of the pond, and additionally includes a lower forward transversely-extending wall 32 which declines rearwardly away from its point of contact with face wire 11 entrained around shell 10, and a lower rearward transverselyextending wall 34 which declines forwardly away from the rear extremity of the headbox or rearward wall section, hereinafter to be referred to.

Lower edges of side walls 28 are connected to the respective end edges of lower forward and rearward walls 32 and 34 respectively on opposite sides of the headbox and their forwardmost end edges terminate adjacent the respective end edge of shell 10 in manner to extend to and conform to the arcuate peripheral surface of its upper quadrant. Suitable fluid-tight sealing means (not shown) is provided at each such juncture for the suitable sealing of the respective headbox side walls to the shell.

The forwardmost transverse edge of lower wall 32 terminates adjacent face wire 11 and may be suitably provided with a flexible sealing means (not shown) secured thereto in manner to extend parallel to the shell axis. Said sealing means preferentially is mounted for limited adjustment of its leading edge toward and away from the face wire for aiding the discharge of stock onto the face wire, for sealing off the lower quadrant of shell 10 therebelow, for precluding unwanted leakage of stock from the approach chamber, and for providing a smooth, continuous floor-line for the fluent stock flowing along and above lower wall 32.

Headbox 26 may be supported upwardly of the foundation as by one or more vertically-extending legs 38 and will communicate with one or more flow spreaders, generally indicated in FIG. 1 by numerals 40 and 42, which preferentially are of the so-called fan or fish-tail type, and are disposed below said headbox, with flow spreader 40 having a main axis extending in a generally vertical plane, and flow spreader 42 having a main axis offset therefrom and angularly disposed relative thereto.

By the use of such a pair of flow spreaders, stock supplies of different characteristics may be employed and may be used simultaneously or alternately, as desired. It will be understood, however, that the use of a pair of such flow spreaders is not obligatory, only one of the same being necessary for normal papermaking purposes.

Flow spreader 40 will be seen to comprise verticallyextending rear and front walls 44 and 46 respectively, which walls may generally converge toward each other from their lower to their upper extremities, and a pair of oppositely-spaced outwardly-inclined side walls 48 each having opposite side edges connected to the adjacent side edges of said rear and front walls, thereby to form an enclosed fan-shaped flow chamber.

Flow spreader 42 may be angularly disposed relative to flow spreader 40, as aforesaid, and may comprise a rear wall 44', a front wall 46, which walls may converge toward each other in manner similar to that of the corresponding walls of flow spreader 40, and a pair of spaced outwardly-inclined side walls 48' having opposite edges connected to the said rear and front walls to form an enclosed fan-shaped chamber.

Each flow spreader has a capacity to convert a fast flowing stock stream of a certain cross-section as it enters thereinto to a faster moving stock stream of relatively wide cross-section at its discharge end, wherefore each not only functions to spread the flow widthwise of the machine but also functions as a turbulence chamber by leading its stock, through the venturi or restricted discharge throat so that it assumes a greatly accelerated velocity across the machine width at its discharge end, thereby preventing any settling out or separation of fiber bundles as well as inducing an even spreading out of the stock across the machine width so as to preclude the development of uneven stock conditions at the web forming area.

Reference will now be made to the form shown in FIG. 2 wherein, for purposes of simplification, I have deleted side frames 2 and their related instrumentalities, and have shown in somewhat diagrammatic form, shell 10, face wire 11 entrained therearound, endless pickup felt 13, pickup roll 15, headbox 26 with only one of its side walls 28 and lower forwardmost wall 32 and lower rearwardmost wall 34, and but a single flow spreader 40 including the rear and front walls 44 and 46 thereof and one of the side walls 48 thereof. Additionally, I have shown a turning roll 17 around which the looped face wire 11 is also entrained and a pressure roll 18, by means of which said wire may be maintained in tensioned operating position.

Said walls 44 and 46 are each of greater width at their tops than at their bottoms so as to provide the aforesaid fan shaped effect, flaring outwardly equidistantly from opposite sides of the center line of the lowermost edges of said walls 44 and 46, which lowermost edges define a point of pulp entry into the flow spreader. The uppermost edges of said walls define a point of pulp discharge therefrom, whereby the stock is constrained to flow vertically upwardly through a passageway having an ever-widening side-to-side dimension or breadth and an ever-decreasing front-to-rear dimension or width. The width of the upper extremity of the flow spreader will correspond substantially to the width of the associated headbox and shell.

The stock inlet (not shown) will lead from a source of pulp supply (also not shown) and into the flow spreader, all as is conventional.

The upper extremity of the flow spreader rear wall 44 merges across its Width with the lower extremity of the flow box lower wall 34 and the upper extremity of the flow spreader front wall 44 merges across its width with the lower extremity of the flow box lower wall 32.

Within headbox 26, a pond or stock. regulator 60 is disposed and may comprise of a pair of transverselyspaced vertically-extending side walls 61, each substantially contiguous with the inner side of its respective adjacent headbox side wall 28, and transversely-extending forward and rearward walls 62 and 64 respectively con nected thereto at opposite sides thereof, which forward and rearward walls converge downwardly toward each other to merge at a lowermost rounded bottom point 66 in a location substantially vertically above the upper mouth or exit of flow spreader 40.

The uppermost portion of forward wall 62 will be suitably configured in an arcuate manner to conform generally with and complement the contour of the ad jacent upper quadrant of shell 10.

Rearward wall 64 will be suitably configured to complement the contour of the flow box rearwardmost wall 34, as shown.

Within the confines of the pond regulator, transverselyextending inner forward and rearward walls 72 and 74 respectively, are connected to the adjacent side walls 60 and converge downwardly to meet substantially centraly of the pond regulator and define an overflow chamber thereabove. A drain opening 76 may be provided in one of the side walls 60 for effecting drainage from said overflow chamber thereby permitting recirculation of the excess stock flowed thereinto, the uppermost and forwardmost extremity of forward wall 62 functioning as a dam to accommodate the overflow of material in excess of the amount which the forming surface of the face wire is capable of receiving, such overflow being flowed downwardly into said overflow chamber.

The pond regulator may be pivoted relative to the headbox vertically upwardly and downwardly and horizontally forwardly and rearwardly lengthwise of and relative to the shell by an adjusting mean 65 provided at the headbox side walls 28, in manner to provide any desired degree of tilt or angularization of said pond regulator to said shell, whereby wall 62 may be adjusted to any desired predetermined position relative to the upper quadrant of the shell so as to effectively control the crosssectional area of the approach chamber 80 defined by the lower forward wall 32 of the headbox, the forward wall 62 of the pond regulator, and the upper quadrant of shell 10, all between the opposite headbox side walls 28 and lengthwise of the machine.

By such approach chamber, the fiow of stock is directed generally upwardly and outwardly through the headbox from the exit of flow spreader 40 to the forming surface of face wire 11 so that the liquid stock or pulp solution for papermaking bears on a segment of the cylindrical forming surface provided by the wire-covered portion of the shell.

Headbox 26 will be observed to be provided with a vertically-adjustable dam 100 at the upper extremity of lower wall 34 and its juncture with the upper extremity of a vertically-extending transverse wall 90.

Spaced rearwardly of and parallel to wall 96] is another vertical wall 92, with the lower edges of walls 90 and 92 being curved toward each other to form a bottom wall 94, said walls 90, 92 and 94 being connected at their opposite side edges by rearwardly extending continuations of the headbox side walls 28 to provide a verticallydisposed excess stock overflow chamber 96 having a drain sump 98 leading therefrom.

The dam 100 may be adjustably fixed to wall 90 and may be slidably adjustable for establishing a desired stock level within the headbox and serving to direct any overflow of stock rearwardly of the pond regulator into and through drain sump 98, for recirculation purposes.

A rotatable rectifier roll or perforated holey roll 102 having the customary rectifier design and function is preferentially transversely-disposed Within throat 80 and may be journalled in the opposite headbox side walls 28 to be extendable across the stock chamber in close running relationship to the adjacent headbox and pond regulator walls where it will bridge the stock exiting from the flow spreader and cause the stock to be passed therethrough to induce turbulence and elfectuate uniform intermingling of the stock fibers and the elimination of accumulations of fiber bundles.

An elongated, flexible, transversely-extending, flexible, membranous wall member 104 is fixed to rearward wall 34 and extends forwardly therefrom toward pond regulator wall 62 in manner to maintain a seal thereat so as to effectuate a pressure within the approach passage by closing off the heel area Within the headbox rearwardly of the pond regulator, while simultaneously allowing of any desired angular adjustment of the pond regulator, and by such seal means, pressure may be built up within the approach passage. That is, flexible wall member 104 defines a closed stock receiving chamber by closing off the heel area rearwardly of the pond regulator so that pressure may be built up within the approach passage merely by the action of the usual stock flow pump (not shown) and without the use of introduced air under pressure, the very pressure of the stock itself serving to force flexible wall member 104 upwardly against the pond regulator and in close running relationship with rectifier roll 102 to achieve the closed-off effect, and all regardless of the angulan'zation of the pond regulator.

By the adjustment of the pond regulator, the cross section of the approach passage, prior to and during formation, may be varied, to allow a precise stock control at the forming area. As the pond regulator is adjusted so as to move pond regulator wall 62 toward or away from shell 10, it serves to close or open throat 80 between wall members 32 and 62 whereby the dimensioning of the cross sectional area of the approach passage is controlled.

Pressure is maintained within the approach passage by bringing the tip of the pond regulator into close proximity with the shell, it being envisioned that it might be brought down to as close as .005". The closer the tip, the greater the pressure which might be applied to the face wire in the forming area, such application of pressure serving to induce a greater drainage in the available forming area. Hence, a more dilute stock might be used, or a heavier sheet might be made than would be possible without such induced pressure. Too, it allows the production of papers having better profile as the sheet is formed from a pond, and is controlled by the drainage rate of the mat on the face wire, rather than by any concentration of fiber in the slurry.

In conventional headbox and slice structures, the slice meters a quantity of water through the orifice. If that volume of water has a uniform fiber suspension across the machine width, it will deposit a uniform web upon the forming area, but when and if that suspension should have a greater concentration of fibers at any point across the machine width, the formed sheet will be heavier thereat. Herewith, inasmuch as a pond of slurry is held against the face wire, and the mat is built up upon the face wire, the resistance to flow increases so that, if a heavy spot should form, the drainage through such heavy spot would be less than at the light spot. With the increased drainage at the light spot, more fibers will be deposited upon the face wire until the drainage rate through the entire web is rendered more uniform.

According to the adjustment of the pond regulator, the cross sectional area of approach passage may be modified at the upper portion of the shell quadrant only, or at the lower portion of the shell quadrant only, 01' throughout the arc of the periphery of said upper quadrant, dependent upon the amount of stock it may be desired to flow onto the forming surface and the velocity thereof.

Within the shell interior, a multicompartment suction box is slidably inserted through one end thereof, upon assembly, and will be butted against the inside of said shell. Suitable rotating means, such as a worm and quadrant assembly (not shown), will allow rotation of said suction box relative to the shell in order to obtain any desired operating position.

Said suction box may be provided with a plurality of separate suction compartments, such as 112 and 114, wherefor the degree of vacuum applied to each may be varied from each other, all as circumstances may require. The separate compartments will be provided with the usual deckle packings for confining the length and width of the respective suction opening, and pressure diflerential will be induced by applying vacuum to the compartments 112 and 114, according to the length of the drop leg employed with each compartment, the depth of each compartment, and the capacity of the pump employed with each compartment.

The shell may also be provided, if desired, with an open free-fall drainage area or white water collecting pan 116 which is located at the bottom of the shell for collecting such water as first drains through the shell and recirculates same, in known manner. Such first drainage comprises a natural drainage due to hydrostatic head and provides an open formation, at the initial forming point where the drainage rate is greatest.

First suction compartment 112 with one degree of suction will normally be submerged in the stock. As the sheet being formed comes out of the pond, second compartment 114 with another degree of suction will take over and serve to dry the web, said second compartment being normally set just beyond the pond and adjacent the edge of the lip of the pond regullator, all to the end that when the stock comes out of the pond, it is held firmly against the wire to eliminate slough and disturbance of formation. Third and fourth compartments may be provided, depending upon the product desired and the speed at which the machine is to be operated.

A plurality of suction boxes may alternatively be provided which are arranged as to each other that they can be moved independently of each other around the inner periphery of the shell to give a greater or less free dr-ainage area, and to vary the time at which each successive vacuum box is called into operational play.

Essentially, the forming area is continuous and the forming is accomplished in a relatively small area, research having established that the drainage area actually extends only a matter of A to V2", whereas on Fourdrinier type machines, considerably longer forming areas, anywhere from 5" to in length, are required.

Additional, and if desired, separate, high vacuum means may be provided within a compartment 118 of the suction box to facilitate additional drainage of water, and more particularly, to control the wetness where the face wire leaves the shell.

Suitable air inlets (not shown) may also be provided adjacent the suction means wherefore small amounts of air may be purposely bled into the vacuum area to counteract the centrifugal force created by the high speed of the rotating shell although, as aforesaid, it is to be appreciated that here, as I take the formed sheet off from the shell with the face wire, and because it has the strength to withstand a slight amount of vacuum, the vacuum box is preferentially so positioned that the face wire lifts therefrom minutely before the end of the box is reached wherefore a small amount of air bleeds into the box and under the sheet. That is to say, atmospheric air bleeds into the vacuum box to replace the air withdrawn by the vacuum so as to minimize the tendency of the water to throw out immediately the formed web moves beyond the vacuum box.

As aforesaid, in this invention, we overcome the tendency due to centrifugal force to throw out water so as to rewet the formed sheet by taking the wire off of the shell before the end of the suction means is reached so as to avoid rewetting.

An additional low pressure vacuum means may be provided whereby any water remaining in the shell may be effectively scavenged thus precluding the possibility of any water being thrown onto the sheet.

It has been found that, where the web is formed rapidly under the influence of suction, and particularly on board webs of substantial thickness, a web having transverse areas of varying thickness is apt to be produced if a uniformly high degree of suction is not present in the forming compartments throughout the forming zone. Suitable means are therefore provided to maintain suction within the compartments so that same will be under a uniform and relatively high degree of suction and a web of uniform characteristics and substantially constant thickness will be formed thereon.

The amount of angular advance of the suction zone will vary with the speed of rotation of the forming shell, the degree of suction employed, the size of the forming shell, the depth of the suction compartments, the capacities of the suction pumps, and the sizes of the dropleg connections.

There has long been considerable disagreement as to what part of the cylinder in a cylinder machine actually did the forming. It is now generally agreed that forming on a cylinder machine is done relatively rapidly and that there are considerable brushing and other disturbances as the cylinder is dragged through the liquid with little additional formation resulting and frequently with a disturbance if not a destruction resulting. In the case of the unit on the other hand, the stock is introduced against the face wire and, immediately it is formed, it is withdrawn from the pond and held in its original formation state, with the compensating feature that the stock coming between the pond regulator and the face wire can be further accelerated by forcing a slight excess of stock thereinto, over and beyond what can possibly be formed with such excess overflowing the lip of the pond regulator, to be collected therein and recirculated.

The formed sheet on the face wire will follow the pickup felt 13 upon contact therewith where it will be led to the subsequent unit. Hence, if a pickup is used which requires that the moisture content at the couch roll be considerably higher than would be required on a Fourdrinier couch, the sheet can be so conditioned, by relieving the vacuum, as to leave sufficient water in the sheet to make it marry with the pickup felt.

Reference will now be made to the modified form of the invention shown in FIG. 3. To avoid repetitious description, similar characters of reference have been applied to the corresponding parts of the forms shown and already described in connection with FIGS. 1 and 2, and I have again deleted, for purposes of simplification, side frames 2 and related components, and have shown, in diagrammatic form, shell 10, face wire 11, endless pickup felt 13, pickup roll 15, turning roll 17, pressure roll 18, headbox 26 with one of its side walls 28 and lower walls 32 and 34 thereof and a single flow spreader 40 including rear and front walls 44 and 46 and one of the side walls 48 thereof. Within said headbox 26, pond or stock regulator 60 is disposed showing only one of its vertically-extending side walls 60, substantially contiguous with the inner side of the respective adjacent headbox side wall 28, and the transversely-extending forward and rearward walls 62 and 64 respectively merging at the rounded bottom point 66.

The uppermost portion of forward wall 62 again is suitably configured to conform with and complement the contour of the adjacent shell quadrant and rearward wall 64 is configured to conform generally with and complement the contour of the lower wall 34. Said wall 64 in this instance will include an uppermost vertically-extending portion 65 which will project upwardly above the uppermost horizontal plane of the headbox, as shown.

Within the pond regulator, the inner forward and rearward walls 72 and 74 respectively will converge downwardly to meet adjacent a drain opening 76 which may be provided in one of the side walls 61.

The uppermost and forwardmost extremity of forward wall 62 of pond regulator 60 will again function as a dam to accommodate any overflow of material in excess of the amount which the forming surface of the face wire is adapted to receive for overflow downwardly into the overflow chamber defined by walls 72 and 74 and out through drain opening 76 for recirculation.

As before, pond regulator 60 may be pivoted angularly relative to headbox 26 upwardly and downwardly and forwardly and rearwardly in manner to provide any desired degree of tilt or angularization to the end that forward wall 62 may be adjusted to any desired predetermined position relative to the shell so as to effectively control the cross-sectional area of the approach passage 80 defined by lower forward wall 32, forward wall 62, and the shell 10, all between the opposite headbox side walls 28.

As before, by means of such approach passage lengthwise of the machine, the flow of stock is directed generally upwardly and outwardly through the headbox from the exit of flow spreader 40 to the forming surface of face wire 11 entrained around shell 10.

The upper extremity of wall 34 is joined to the upper extremity of a vertically-extending transverse wall and spaced rearwardly of and parallel to said wall 90 is another wall 92, with the lower edges of walls 90 and 92 being curved toward each other to form a bottom wall 94, with the walls 90, 92 and 94 being connected at their opposite side edges by rearwardly extending continuations of headbox side walls 28 to provide a vertically-disposed excess stock overflow chamber 96 having a drain sump 98 connected thereto for recirculation purposes, the overflow chamber being controlled by a pressure means over the stock level L, as will appear.

A rotatable rectifier roll or perforated holey roll 102 is again transversely-disposed at .he rearward lowermost portion of throat 80 and journalled at its opposite ends in headbox side walls 28, so as to be extendable across the stock chamber in close running relationship to the walls 13 to serve the stock bridging function and to induce turbulence and to effectuate more uniform intermingling of the stock fibers and elimination of accumulations of fiber bundles as the stock is passed therethrough.

The top of overflow chamber 96 is enclosed by means of a flexible cover member 130 connecting between the topmost edges of wall 92 and the wall portion 65 of pond regulator 60 wherefor an enclosed headbox is attained. Air pressure may thus be established in the upper portion thereof to maintain the stock at a relatively low level behind throat 80 and without diminishing the flow onto the forming shell as compared with the conventional practice of maintaining a high level of stock therebehind. Being flexible, as pond regulator 60 is adjusted to various positions, said cover member 130 is movable accordingly.

Stock level L within overflow chamber 96 and within the headbox will be maintained by a control means, subsequently to be described.

With this arrangement, the head of incoming stock is flowed through the stock inlet to flow spreader 40 where it takes the shape of an upwardly and outwardly diverging stream and out of the mouth or exit thereof, into the rearward extremity of throat 80 and through rectifying means 102 therewithin, and is then exited forwardly through throat 80 for discharge onto the face wire.

The head is controlled within throat 80 by pond regulator 60 which is angularly adjustable by the aforesaid adjusting assemblies to regulate the flow of stock through said throat which in turn distributes the flow over the apron to the moving face wire.

With this arrangement, stock flow to the face wire may be suitably regulated without altering the stock head and moreover, regulation of the pond regulator can be effected without stopping the forming operation. In fact, such regulation is more effective during operation for the reason that the results will appear as the formed sheet is drawn off from the face wire.

By the provision of recirculation chamber 96, any excess stock may flow through the heel of the headbox and into said chamber, forming therein at a level L as determined by the amount of air pressure thereover.

The level within overflow chamber 96 will be controlled by a control means 132 of conventional design which will be connected by a line 133 to a valve means 134, which valve means will open and close, as directed, so as to effectuate the discharge of excess air pressure from chamber 96.

Excess stock will flow from chamber 96 through drain sump 98 and into conduit 136 and into a container 138 and the amount of such flow will be automatically controlled by a flow meter 140 of known construction which will deliver appropriate intelligence through line 141 to a control panel 142 of conventional design which will be of such capacity as to effectuate the appropriate opening or closing of valve 144 through a line 143.

Control panel 142 will incorporate means which may be preset so as to provide the amount of recirculation required. Should a greater amount pass through flow meter 140, such intelligence will be transmitted to control panel 142 whereupon valve 144 will be automatically closed to restrict further flow.

By means of this construction, the sheet may be formed upon the face wire, drained by the suction boxes within the shell, and then dried by the suction boxes, with the drainage water being evacuated into the suction boxes or being held within the shell by the induced vacuum.

By entraining the face wire in this manner, the face wire acts as a backing for the sheet, whereby the sheet may be lifted off the curved surface of the shell and carried in a straight line to the point of transfer at the pickup roll.

Additionally, the sheet may be lifted from the shell even though there be vacuum under the wire at the point of separation, wherefore atmospheric air may pass into the suction box or boxes to evacuate water from the openings in the shell to control the ever-present problem of water roll-out, wherefore there would either be no throw-01f, or the water would throw out at a point slightly beyond the point where the face wire is removed, and hence travel in a direction away from the face wire, so as not to disturb the sheet on the face wire. a

From the foregoing it will be appreciated that I have delineated constructions permitting the deposition of stock upon a web forming surface of a face wire entrained around a rotating foraminous shell, and in a means for removing the formed felted web or sheet product from the web forming surface, with the advantage that the web is permitted to be formed upon the face wire then dried by a suction means disposed within the shell, with the drainage water being evacuated thereinto or at least held in the shell by a vacuum system, and subsequently to be picked up from the face wire by a pickup roll, with the wire acting as a backing for the formed sheet and the sheet being lifted off from the arcuate surface of the shell by the wire, even though there may be a vacuum under the wire at the point of separation of wire and shell, with the sheet being thence carried in a straight line to a transfer point. By such arrangement, I permit a leakage of air into the suction box or boxes wherefor the problem of the roll-out of water is controlled to the point where there is either no throw off or the water throws out at a point slightly beyond the point of separation of shell and wire and hence in a direction away from the direction of travel of the wire so as not deleteriously to affect the sheet on the wire.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a papermaking machine having a foraminous cylindrical shell rotatable on a horizontal axis, a turning roll spaced from said shell and rotatable on an axis parallel with the horizontal axis of said shell, an endess travelling web forming wire entrained around said shell and turning roll and defining therewith a continuous wire loop, a stock receiving chamber having a stock inlet and being positioned adjacent said shell and the portion of said forming wire entrained therearound and communicating therewith at an upper forming portion of the ascending side of said shell, means for supplying stock into said stock receiving chamber through the stock inlet thereof, a pond regulator positioned within said stock receiving chamber, said pond regulator having side walls and a back wall and a front wall, said front wall defining cooperantly with adjacent portions of said stock receiving chamber and shell, an adjustable approach passageway leading from said stock receiving chamber to said shell and disposed substantially tangential to the direction of travel of the adjacent portions of said shell and forming wire, said pond regulator being adjustably mounted Within said stock receiving chamber for varying the cross sectional area of the approach passageway and allowing a control of the velocity of the stock slurry delivered from said stock receiving chamber onto said forming wire and shell, the upper forming portion of the ascending side of said shell and an adjacent upper portion of the descending side of said shell constituting a web forming zone, said pond regulator front and back walls converging downwardly toward each other and merging at a lowermost bottom point and suction means interiorly of said shell and in sealed relationship therewith along the inner circumference thereof to define an arcuate length along the circumference substantially coextensive with the web forming zone and connected to a source of vacuum for effecting removal of effluent water from the stock slurry during deposit on said wire, the improvement comprising a flexible membraneous sealing means disposed within and secured to an interior wall of said stock receiving chamber along a line in a horizontal plane at substantially the same level as the rounded bottom of said pond regulator and extendable toward and engageable with said pond regulator for continuously defining therebelow a closed compartment within said stock receiving chamber under any adjusted position of said pond regulator for allowing stock pressure build up within the closed compartment according to a desired predetermined velocity of the stock slurry delivered to said forming wire.

2. In the papermaking machine as set forth in claim 1, including a secondary high suction means interiorly of said shell and in sealed relationship therewith along the inner circumference thereof to define an arcuate length along the circumference substantially coextensive with the extremity of the web forming zone and slightly beyond the point where said forming wire leaves said shell and connected to a source of vacuum for further effecting removal of effiuent water from the stock slurry deposited on said forming wire while allowing said forming wire to 1 5 lift from said shell before the limit of said secondary high suction means is reached.

References Cited by the Examiner UNITED STATES PATENTS 2,162,097 6/39 Metcalf 162-317 2,942,662 6/60 Goodwillie 162-317 2,943,678 7/60 Fasoli 162--321 2,971,580 2/61 Beachler et a1. 162-340 FOREIGN PATENTS 578,379 6/58 Italy.

DONALL H. SYLVESTER, Primary Examiner.

RICHARD D. NEVIUS, Examiner.

Claims (1)

1. IN A PAPER MAKING MACHINE HAVING A FORAMINOUS CYLINDRICAL SHELL ROTATABLE ON A HORIZONTAL AXIS, A TURNING ROLL SPACED FROM SAID SHELL AND ROTATABLE ON AN AXIS PARALLEL WITH THE HORIZONTAL AXIS OF SAID SHELL, AN ENDLESS TRAVELING WEB FORMING WIRE ENTRAINED AROUND SAID SHELL AND TURNING ROLL AND DEFINING THEREWITH A CONTINUOUS WIRE LOOP, A STOCK RECEIVING CHAMBER HAVING A STOCK INLET AND BEING POSITIONED ADJACENT SAID SHELL AND THE PORTION OF SAID FORMING WIRE ENTRAINED THEREAROUND AND COMMUNICATING THEREWITH AT AN UPPER FORMING PORTION OF THE ASCENDING SIDE OF SAID SHELL, MEANS FOR SUPPLYING STOCK INTO SAID STOCK RECEIVING CHAMBER THROUGH THE STOCK INLET THEREOF, A POND REGULATOR POSITIONED WITHIN SAID STOCK RECEIVING CHAMBER, SAID POND REGULATOR HAVING SIDE WALLS AND A BACK WALL AND A FRONT WALL, SAID FRONT WALL DEFINING COOPERANTLY WITH ADJACENT PORTIONS OF SAID STOCK RECEIVING CHAMBER AND SHELL, AN ADJUSTABLE APPROACH PASSAGEWAY LEADING FROM SAID STOCK RECEIVING CHAMBER TO SAID SHELL AND DISPOSED SUBSTANTIALLY TANGENTIAL TO THE DIRECTION OF TRAVEL OF THE ADJACENT PORTIONS OF SAID SHELL AND FORMING WIRE, SAID POND REGULATOR BEING ADJUSTABLY MOUNTED WITHIN SAID STOCK RECEIVING CHAMBER FOR VARYING THE CROSS SECTIONAL AREA OF THE APPROACH PASSAGEWAY AND ALLOWING A CONTROL OF THE VELOCITY OF THE STOCK SLURRY DELIVERED FROM SAID STOCK RECEIVING CHAMBER ONTO SAID FORMING WIRE AND SHELL, THE UPPER FORMING PORTION OF THE ASCENDING SIDE OF SAID SHELL AND AN ADJACENT UPPER PORTION OF THE DESCENDING SIDE OF SAID SHELL CONSTITUTING A WEB FORMING ZONE, SAID POND REGULATOR FRONT AND BACK WALLS CONVERGING DOWNWARDLY TOWARD EACH OTHER AND MERGING AT A LOWERMOST BOTTOM POINT AND SUCTION MEANS IN-

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