US3802960A

US3802960A - Method and apparatus for conditioning paper stock flowing to papermaking machine

Info

Publication number: US3802960A
Application number: US00243386A
Authority: US
Inventors: A Spengos; R Kaiser
Original assignee: Scott Paper Co
Current assignee: Kimberly Clark Tissue Co
Priority date: 1972-04-12
Filing date: 1972-04-12
Publication date: 1974-04-09
Anticipated expiration: 1991-04-09

Abstract

A method and apparatus are disclosed for conditioning paper stock flowing to a papermaking machine, which improves the uniformity of fiber dispersion in the paper stock and results in the formation of a flow having a uniform velocity profile across its width. The method and apparatus of the invention also enables flocculation of the fibers in the paper stock to be influenced and in some embodiments of the invention to be controllably regulated. A preferred embodiment of the apparatus includes inner and outer flow control members coextensive with each other and defining an elongated chamber having a generally annular crosssection, and at least one group of conduits of substantially equal cross-sectional area communicating with the elongated chamber and with a paper stock delivery pipe receiving paper stock from a headbox. The conduits are adapted to introduce paper stock through the outer flow control member and to impinge the paper stock against the inner flow control member in a manner which diffuses the paper stock and causes it to flow in both directions about the inner flow control member perpendicularly to the elongate dimension of the member. In some embodiments, the two streams of paper stock flowing in opposite directions about the inner flow control member merge together before being deposited upon a paper forming surface. In other embodiments, separation of the two streams is maintained until deposition by a tail extension extending downstream from the inner flow control member. The flocculation of the fibers in the paper stock can be controllably regulated by adjusting the position of the inner flow control member relative to the outer flow control member so as to change the configuration of the cross-section of the elongate chamber. In some embodiments, a plurality of different paper stocks can be flowed through the chamber and deposited upon a paper forming surface in layers. And in another embodiment, a single paper stock is flowed about the inner flow control member in one direction only.

Description

United States Patent [191 Spengos et a1.

[ METHOD AND APPARATUS FOR CONDITIONING PAPER STOCK FLOWING TO PAPERMAKING MACHINE [75] Inventors: Aris C. Spengos, Wallingford;

Richard B. Kaiser, Swarthmore, both of Pa.

[73] Assignee: Scott Paper Company, Philadelphia,

[22] Filed: Apr. 12, 1972 [21] Appl. No.: 243,386

[52] US. Cl 162/216, 162/298, 162/336, *162/338, 162/341, 162/343 [51] Int. Cl. D2lf l/06 [58] Field of Search 162/343, 347, 342, 341, 162/338, 336, 298, 216, 123

1 [56] References Cited UNITED STATES PATENTS 1,534,080 4/1925 Russell 162/336 X 1,782,215 11/1930 Sheperd 162/298 I 3,652,391 3/1972 Spengos et 162/343 3,298,905 l/l967 Spengos et al..... 162/343 3,255,074 6/1966 Salomon et al. 162/338 3,598,696 8/1971 Beck 162/343 X 3,016.089 l/l962 Webster 162/339 FOREIGN PATENTS OR APPLICATlONS 186,518 8/1956 Austria 162/336 Primary E.\'aminerS. Leon Bashore Assistant E.\'aminerRichard V. Fisher Attorney, Agent, or FirmR. Duke Vickrey; W. J. P0- ley; J. W. Kane ABSTRACT I A method and apparatus are disclosed for conditioning paper stock flowing to a papermaking machine,

[451 Apr. 9, 1974 which improves the uniformity of fiber dispersion in the paper stock and results in the formation of a flow having a uniform velocity profile across its width. The

method and apparatus of the invention also enables flocculation of the fibersin the paper stock to be influenced and in some embodiments of the invention to be controllably regulated. A preferred embodiment of the apparatus includes inner and outer flow control members coextensive with each other and defining an elongated chamber having a generally annular crosssection, and at least one group of conduits of substantially equal cross-sectional area communicating with the elongated chamber and with a paper stock delivery pipe receiving paper stock from a headbox. The

conduits are adapted to introduce paper stock through the outer flow control member and to impinge the paper stock against the inner flow control member in a manner which diffuses the paper stock and causes it to flow in both directions about the inner flow control member perpendicularly to the elongate dimension of the member. In some embodiments, the two streams of paper stock flowing in opposite directions about the inner flow control member merge together before being deposited upon a paper forming surface. 1n other embodiments, separation of the two streams is maintained until deposition by a tail extension extend: ing downstream from the inner flow control member. The flocculation of the fibers in the paper stock can be controllably regulated by adjusting the position of the inner flow control member relative to the outer flow control member so as to change the configuration of the cross-section of the elongate chamber. In some embodiments, a plurality of different paper stocks can be flowed through the chamber and deposited upon a paper forming surface in layers. And in another embodiment, a single paper stock is flowed about the inner flow control member in one direction only.

43 Claims, 13 Drawing Figures PATENTEDAPR 9 I974 SHEET 2 [IF 5 METHOD AND APPARATUS FOR CONDITIONING PAPER STOCK FLOWING TO PAPERMAKING MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method and apparatus for conditioning liquid-fiber mixtures and, more particularly, is directed to the conditioning of paper stock to be deposited onto the forming surface of a papermaking machine in a manner which causes the velocity profile of the flow to be substantially uniform, and flocculation of the fibers to be influenced or controllably regulated.

2. Description of the Prior Art In papermaking, it is customary to transform the flow of paper stock from the shape resulting in a confined pipe to that of a relatively wide flat stream or flow for depositing upon the forming surface of the papermaking machine. It is particularly desirable that the flow have uniform velocity across its width and have a substantially uniform fiber concentration across its width, so as to produce a paper web having uniform thickness and density when the paper stock is deposited onto the forming surface and drainage occurs. In the past, attempts to establish uniform distribution of fibers in the paper stock, to maintain fiber distribution once established, and to obtain a substantially uniform velocity profile across the width of the slice have involved the use of a wide variety of equipment and combinations of equipment involvingdifferent flow paths as well as auxiliary equipment such as perforated rotary rolls, often referred to as rectifier rolls, holey rolls or silencing rolls.

Examples of prior art equipment include: those which involve different flow paths, such as equipment disclosed in U.S. Pat. Nos. 3,016,089 and 3,607,625; those which employ flow obstacles to create paper stock turbulence, such as equipment disclosed in U.S. Pat. Nos. 1,534,080 and 2,832,268; those which offer flow control with movable internal members, such as the equipment disclosed in U.S. Pat. Nos. 2,339,730, 2,870,690 and 3,536,582; those which employ a plurality of internal flow control members situated across the width of the slice to create uniform flow velocity across the slice, such as the equipment disclosed in U.S. Pat. Nos. 3,135,650 and 3,098,787; and those which employ perforated rotary rolls, such as the equipment disclosed in U.S. Pat. Nos. 2,911,041, 3,014,527, 3,038,538, 3,065,788, 3,074,476 and 3,575,800.

All of these prior art examples have some disadvantages. For example, almost all of the equipment is very bulky and complex. Most of the equipment does not offer controllable regulation over the fiber flocculation. And most do not offer the highly uniform flow velocity across the width of the slice which is necessary for the production of high quality paper products.

Of primary importance in designing equipment for conditioning flowing paper stock is control of flocculation. Flocculation is the creation of bundles of fibers in the fiber stock. These bundles of fibers are often referred to in the art as clots, flocs or agglomerations. When such flocs are of undue size and distribution, and are deposited upon a drainage surface, they can cause undesirable irregularities in the paper sheet formed.- Often, these irregularities are in the form of localized I ferent properties inside of the paper.

areas of high density in the paper sheet separated by' areas of unreasonably low density, giving the resulting sheet a mottled appearance. Where the creation of flocs is quite severe, the paper web breaks down completely and interrupts production.

Flocculation can be controlled by varying the velocity of the flowing paper stock. For example, accelerating the flowingpaper stock generally decreases flocculation size and decelerating the flowing paper stock generally increases flocculation size. However, other effects on the paper are also experienced when the velocity of the paper stock is varied. When accelerated, the paper fibers tend to align'in their direction of flow; when decelerated, they tend to align perpendicular to their direction .of flow. Excessive alignment in either direction weakens the resulting paper web in the other direction and is undesirable. Furthermore, it is impracticable to eliminate all flocculation in normal papermaking operation. Therefore, the goal for satisfactory flow conditioning equipment is to be capable of controlling flocculation to produce the size, number and distribution of flocs allowable for paper products of acceptable quality without creating excessive alignment of the fibers.

It would be highly desirable to be able to adjustably control flocculation to maintain acceptable flocculation conditions on a particular machine even if process conditions are varied, such as changing the stock consistency or fiber content, or changing the flow rate of the fiber stock. It would also be desirable for a single papermaking machine to makeproducts of different properties and quality with only a minor adjustment to the machine.

One method of reducing the effect of irregularities in the paper density would be to overlay one slice having a particular flocculation pattern with another slice having a different flocculation pattern. The random overlay of one pattern over another reduces the likelihood of drastic concentration variations in the composite sheet formed. Also, it is readily apparent that if two layers in a paper composite decrease concentrations of flock, then three or more layers will be even more effective. It may also be desirable to overlaytwo or more layers of totally different paper stock to produce paper having different properties on each side or, perhaps dif- The use of multiple slices to'form a composite sheet is known in the papermaking industry. U.S. Pat. Nos. 3,384,537 and 3,598,696 disclose examples of equipment for this purpose. But in the past such equipment has been limited to multiple pieces of paper conditioning equipment, each piece having its own supply of stock andthe flow from each piece flowing through a separate conditioning chamber before reaching the forming wire. The disadvantages of using multiple pieces of equipment are obvious,as they are not only large and space consuming, but each piece must be individually controlled.

complished with a compact and simple conditioning chamber. All of these goals can be accomplished by one or more embodiments of the invention, and some can be accomplished by all of the embodiments.

BRIEF SUMMARY OF THE INVENTION The apparatus of the invention features an elongated paper stock conditioning chamber which uniquely combines the advantages of compactness, structural rigidity, control and adjustability of flocculation pat The inner surface faces the paper stock flow entering the chamber at an abrupt angle, thus causing the entering stock flow to' impinge upon the inner surface and diffuse, resulting in substantially uniform flow profile across the width of the stream. After impingement, the

5 justed. At one position, the inner cylinder is centered stock is flowed in a path generally defining a circular arc to rapidly, yet notabruptly, bring the stock flow back into the direction it had upon entering'the chamber.

While flowing through the arcuate path formed by the chamber surfaces, the velocity of the stock can be varied to create desired flocculation patterns by varying the spacing between the inner and outer surfaces. The spacing at any position downstream in the chamberis maintained at a uniform distance at that position across. the entire width 'of the chamber in order to maintain uniform flow of the paper stock across the width of the stream. Upon leaving the flow chamber, the stock is conducted through a wide, thin flow nozzle to the sliceat the forming surface of a papermaking machine.

lit a preferred embodiment of the invention, the outer wall is provided by a cylinder modified symmetrically about a plane extending through the elongate dimension of thecylinder. to unabruptly join with the flow nozzle leading to the slice. The inner wall is provided by a smaller cylinder modified symmetrically about a plane extending through the elongate dimension of the cylinder .to form, a streamlined tail extension on the downstream side of the cylinder, the cross-sectional shape of the inner cylinder being similar to a teardrop. For simplification throughout the specification and claims, the inner and outer walls shall be referred to as the inner and outer cylinders, although they are not true cylinders.

. The inner cylinder is positioned with its planeof symmetry passing throughthe chamber inlet and outlet, so

that the paper stock flowing into the chamber impinges against the bluntest end of the inner cylinder and is dis- 7 persed in both directions around it. The two streams of paper stock flow about opposite sides of the inner cylinder and merge together again at the outlet of the chamber.

In another embodiment of the invention, the tail extension on the inner cylinder is extended into the flow nozzle to resist complete merging of the two streams in the flow nozzle. The tail extension can even be exwithin the outer cylinder so that the spacing between the inner and outer walls is uniform through the chamher from the inlet to the outlet. In another position, the inner cylinder is positioned closer. to the chamber inlet, creating a gradually increasing spacing between the inner and outer walls as the stock flows downstream through the chamber. In yet another position, the inner cylinder is positioned closer'to the chamber outlet, creating ag'radually decreasing spacing between the inner and outer walls as the stock flows downstream through the chamber. In making these adjustments, it is usually preferable'for the planes of symmetry of the two cylinders to be co-extensive. But it would be possible to place the inner cylinder where the planes would not be co-extensive to create different flocculation patterns for each of the flow streams passing around the inner cylinder.

In order to enhance uniform flow profile across the width of the slice, it is preferable that the inlet consist of a plurality of equal-size flow conduits equally spaced across the width of the chamber in one or more rows, for flowing discrete streams of paper stock at a common velocity. The advantages of providing a plurality of equal-size, equally spaced flow conduits for the chamber inlet are set forth in U.S. Pat. No. 3,298,905. Additional enhancementof uniform flow profile can be gained by placing flow barriers between each inlet conduit, in the manner described in U.S. Pat. No. 3,652,391. 1 Y

In another embodiment of the invention, the chamber inlet can be provided for by eitherthe diffusing chamber described in U.S. Pat. No. 3,298,905 or the one described in U.S. Pat. No. 3,652,391, in which case the diffusing chamber is entered by a plurality of equalsize, equally spaced conduits. Thus, the disclosures of U.S. Pat. Nos. 3,298,905 and 3,652,391 are incorporated by reference into this specification.

In another embodiment of theinvention, a flow partition extends between the inner cylinder and the outer cylinder atthe inlet end of the chamberand for the full width of the chamber to separate the two flow channels about the inner cylinder. in this embodiment the chamber has two inlet means, one on each side of the partition. With this arrangement, two distinctively different paper stocks can be flowed through the chamber at the same time, to join together downstream of the inner cylinder. The degree to which the two distinctive paper stocks merge or remain stratified after coming together is controlled by the extent to which the inner cylinder tail extension extends downstream toward the slice.

In yet anotherembodiment of the invention a conduit is extended through the flow partition and through the inner cylinder. With this embodiment a third stream, and if desired even more streams, can also be flowed through the chamber of the invention to produce a paper having three or more Stratified layers.

It should be noted that the dual inlet embodiment of the invention described above can be used with paper stock flowing through only one inlet and still retain the advantages of the adjustability of the flock pattern and the compact structural advantages of the cylindrical shape of the chamber. In fact, the chamber could be constructed of only one-half of the cylindrical chamber and produce many of the advantages of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional elevation view of a specific embodiment of the paper stock conditioning chamber of the invention in position to discharge paper stock upon the forming surface of a papermaking machine.

FIG. 2 is a sectional plan view of one end of the chamber illustrated in FIG. 1.

FIG. 3 is a partial perspective view of the chamber illustrated in FIG. 1 and FIG. 2 with portions exposed to illustrate details.

FIG. 4 is an end view of the chamber of the invention illustrating means to adjust the position of the inner cylinder within the outer cylinder.

FIG. 5 is a sectional elevation view of a second specific embodiment of the paper stock conditioning chamber, of the invention.

FIG. 6 is a partial perspective view of the chamber illustrated in FIG. 5 with portions exposed to illustrate details.

FIG. 7 is a sectional elevation view of a third embodiment of the invention.

FIG. 8 is a sectional plan view of one end-of the chamber of the invention taken along line 88 of FIG. 7.

FIG. 9 is a partial perspective view of the chamber illustrated in FIG. 7.

FIG. 10 is a sectional elevation view of a fourth embodiment of the invention.

FIG. 11 is a partial perspective view of the chamber illustrated in FIG. 10.

FIG. 12 is a sectional elevation view of a fifth embodiment of the invention.

FIG. 13 is a sectional elevation view of a sixth embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific preferred embodiment of the invention is Y illustrated in FIGS. I through 3 where the paper stock conditioning chamber is indicated generally by numeral 20. Paper stock flows into the chamber 20 through a plurality of small conduits 21 arranged in one or more rows, which are supplied the paper stock from the header 22. After the paper is conditioned in the chamber 20, it passes through the flow nozzle 23 and to the slice 24 at the forming surface 25 of a papermaking machine, illustrated here as suction forming roll 26, pickup 27, and traveling felt 28.

The chamber 20 consists basically of two parts, inner wall means 29 and outer wall means 30. The outer wall means 30 is basically a cylinder which extends parallel to and for approximately the full length of the forming surface 25. The cylinder 30 is modified on the downstream side of the chamber to smoothly join with the upper and lower confining membersof the flow nozzle 23.

The inner wall means 29 is also basically a cylinder which is disposed within and extends for the full length of the outer cylinder 30. On the downstream side, the inner cylinder 29 is modified to smoothly form a tail extension 31 which serves to bring the two separate flow streams flowing around both sides of the inner'cylinder 29 back together without creating undesirable turbulence.

It should be noted that the tail extension 31 can, if desired, be extended through the flow nozzle 23 all the way to the slice 24, in which case greater stratification of thetwo separate flow streams is maintained upon deposition of the paper stock upon the forming surface 25. It should also be noted that it is within the scope of the invention to provide an inner cylinder 29 without a tail extension 31. However, at least a short tail extension 31 is desirable to prevent undesirable turbulence where the two separate flow streams rejoin. Proper length and design of the tail extension will allow substantial stratification of the two separate flow streams after they come into contact with each other.

US. Pat. No. 3,298,905 to Spengos et al teaches that a highly uniform flow can be achieved across the width of a flow chamber having an inlet consisting of a plurality of branch tubes, if certain critical relationships are maintained between the flow area in the chamber and the flow areas and disposition of the branch tubes. It has been found that maintaining these same critical relationships with the embodiment of the invention as shown in FIGS. 1 through 3 also enables the achievement of a highly uniform flow across the width of the flow chamber 20. These relationships are expressed in the following equation, which refers to dimensions indicated in FIGS. 2 and 3.

A ZSW/n'd wherein A is a dimensionless ratio S is the distance between center lines of the branch tubes 21,

W is the spacing between the upstream side of the inner cylinder 29 and the inlet through the outer cylinder 30, and

d .4 is the diameter of the branch tubes 21.

' It will be noted that in the above equation, A is an expression of the ratio of the incremental flow areas in the chamber 20 between center lines of branch tubes 21 (SW) to the flow areas of the branch tubes 21 (1rd /4). Obviously, if the apparatus under consideration employed branch. tubes having cross sections other than circular, then the equation for It should be modified to reflect the flow area for the particular cross section used. It should be noted that the chamber illustrated in FIG. 1 has two flow paths, and therefore, the total flow area is 2SW. In other embodiments where there is only one flow path available for the stock coming from any one branch tube 21, such as illustrated in FIGS. 10, 11, 12 and 13, the formula must be modified to A 4SW/1-rd Iiikewi'se, if the branch tubes 21 are arranged in more than one row, adjustment must be made to the formula.

It has been determined that optimum production of uniform flow in chamber 20 can be achieved with a k value of approximately 1.5 and that good results can be achieved when his maintained within the range of from about 1.1 to about 1.7. Since the paper stock is a substantially incompressible fluid, its flow velocity is inversely dependent upon the flow area. Thus increasing the flow area by l.l reduces flow velocity by 0.9 and increasing the flow area by 1.7 reduces the flow velocity by 0.6. i

In striving to maintain a highly uniform flow across the width of the flow chamber 20, the embodiment of the invention shown in FlGS. 1 through 3 employs another principle taught in US. Pat. No. 3,298,905. That .21 spaced equally along a tapered header 22. The

header is tapered to maintain substantially the same header pressure at all branch tubes 21. It is preferable thatthe smaller end of the header 22 connects with a return pipe (not shown) through which a portion of the stock flow through the header 22 may be recirculated to the stock mixing and pumping portion of the papermaking machine.

In FlG. 1, the flow nozzle 23 is illustrated with means to adjust its degree of convergence downstream of the chamber 20. The upper plate is shown having two pivots 33 and two adjusting members '34 to move the upper plate up or down and thereby vary the spacing between the nozzle plates; The velocity as well as discharge pressure of the paper stock at the slice 24 can be varied by moving the adjusting members 34. It

should be recognized, however, that the chamber of the invention can be used effectively with a flow nozzle 23 of fixed platesL-It should also be recognized that the'adjustrnent features of the flow nozzle 23 illustrated in FIG. 1 may also be included in other embodiments of the invention and are so illustrated in FIGS. 5, 7, and 12.

The chamber of the invention may be used advantageously with the inner cylinder mounted in a fixed position within outer cylinder and with the planes of symmetry of both cylinders being co-extensive. With this arrangement, it may be preferable that'inner cylinder 29 be positioned toward the inlet tubes 21 so that the spacing between the inner and outer cylinders gradually increases downstream in the chamber 20. However, the invention lends itself readily to include means for adjustingthe inner cylinder 29 within the outer cylinder 30.

The adjustment means 35, which may also be employed with the other embodiments shown, are illustrated in FIGS. 2 and 4 (and FIG. 8 for another embodirnent) where the inner cylinder 29 has shafts 36 exof the cylinders. This adjustment is made by two set bolts 41, each passing through a threaded opening of an angle clip 42 and abutting against opposite sides of the yoke means 39.

.Rotation of shaft 36 within the yoke means 39 is pre-' vented by the bar 43 setting in a notch in the end of shaft 36 and bolted to the yoke means 39. Rotation of the yoke means 39 is prevented by smooth rods 44'extending through holes inyoke means 39 on either side of the shaft 36 and being rigidly held by the angle clips 42. The anglec'lips'42- are held, to the end walls38 of thechamber 20 by bolts 45 passing through slots 46 in the angle clips. All adjustments other than those along the common planes of symmetry of the cylinders are made by loosening the bolts 45 and moving the angle clips 42 to the desired location before again tightening the bolts 45.

Adjusting the position of the inner cylinder 29 offers several advantages. For one, the position of the inner cylinder 29 can be adjusted with respect to the inlet of chamber 20 to either accelerate or decelerate the paper stock flowing through the chamber 20, and thus change the flocculation pattern. For another, the )t ratio as expressed in the preceding formula can be varied to produce optimum flow uniformity across the width of the flow chamber. And for another, the inner cylinder 29 can be moved up or downor rotated slightly about its shafts 36 to create different flocculation patterns for each of the two flow paths about the inner cylinder 29. Of course, it can easily be apprecia ted that movement of the inner cylinder 29.is generally limited to movement along the common axis of symmetry of the inner and outer cylinders if the tail extension 31 extends far into the flow nozzle 23. 8

Referring now to FIGS. 5 and 6, another embodiment of the invention is illustrated. This embodiment is like the embodiment illustrated in H08. 1 through 3, but with the addition of barrier means 48 placed between the inlet of each branch conduit 21 entering the chamber 20. The barriers 48 insulate the flow from each branch conduit 21 from the effects of the flow from its adjacent branch conduits 21. Without the barrier means 48, there is a tendency for a part of each stream entering the chamber to flow sideways upon impingement against the inner cylinder 29. The sideways flow can create eddies which disrupt to some extent the uniform flow across the width of the chamber 20.

US. Pat. No. 3,652,391 to Spengos et al teaches the use of barrier means placed between branch conduits entering a diffusion chamber for the purpose of improving flow uniformityacross the width of the chamber. In that patent, the barrier means are provided by triangular shaped elements having points extending downstream in the chamber. This design can be applied to the present invention also, but modified to extend in both flow directions about the inner cylinder 29 from v the inlets of the conduits 21. The most desirable shape, therefore, is a rhombus in one plane and curved in another plane to conform to the curvatures of the inner cylinder 29 and the outer cylinder 30.

The length of the barriers 48 can be varied somewhat with satisfactory results, but it should be at least as long as the diameter of the inlet conduits 21. It is preferable for the width of the barriers 48 to extend substantially from the edges of adjacent conduits 21 so as to gradually increase the inlet stream width from the diameter of each conduit 21 to its pro-rata portion of the total chamber 20 width.

The use of barrier means 48 with the chamber of the invention can interfere somewhat with the adjustability of the inner cylinder 29 within the outer cylinder 30. However, some adjustability can be retained by using an elastomeric material for the barrier means 48. Another method of retaining adjustability of the inner cylinder 29 with the outer cylinder 30 is through use of cavities within either the inner cylinder 29 or the outer cylinder 30 adapted for the barrier means 48 to slide into whenever the inner cylinder 29 is moved toward the barrier means 48. Of course, with this latter arrangement, adjustability is limited to movement along the common plane of symmetry of the inner and outer cylinders. The adjustment means 35 illustrated in FIG. 4 can be used with the embodiment of. the invention shown in FIGS. 5 and 6.

Another embodiment of the invention is illustrated in FIGS. 7, 8 and 9. ln this embodiment, chamber 20 of the invention is preceded by the box-like blending chamber 49 disclosed in U.S. Pat. No. 3,298,905. Paper stock is fed into the box-like blending chamber 49 from a series of parallel branch laterals 21 and discharged as blended stock into the chamber 20 through a slotted opening 51 extending the full width of the chamber 20. As described in U.S. Pat. No. 3,298,905, the branch laterals 21 conduct flowing paper stock in equally spaced apart, equal velocity discrete streams from the header 22 into'the bottom of the box-like blending chamber 49.

The box-like blending chamber 49 can be further modified to include barrier means (not shown) between the inlets of the branch conduit 21 according to the teaching of U.S. Pat. No. 3,652,391. When the chamber 20 of the invention is preceded by the boxlike blending chamber 49 of U.S. Pat. No. 3,298,905 or of U.S. Pat. No. 3,652,391, the critical relationship of the flow area of the branch conduit to the flow area in the chamber as expressed by A in the preceding equation is preferably maintained where the branch conduits 21 enter the box-like blending chamber 49. However, it is not necessary to maintain that critical relationship where blending chamber 49 enters the chamber 20 because the chamber 20 then serves the primary purpose of creating flocculation patterns, because uniform flow over the width of the chamber 20 has been substantially achieved with the box-like blending chamber 49.

Another embodiment of the invention is illustrated in FIGS. and 11. The embodiment is capable of conditioning two different paper stocks in the chamber of the invention and depositing them in stratified layers upon the forming surface of a papermaking machine. The papermaking machine is illustrated here as a fourdrinier wire 52 passingaround a breast roll 53 and over a forming box 54. The first paper stock is supplied through one header 22a, through branch tubes 21a and into chamber approximatelyin the same manner that paper stock enters the chamber in the embodiment illustrated in FIGS. 1 through 3. The second paper stock is supplied through a second header 22b, through branch tubes 21b and into chamber 20. In this embodiment, branch tubes 21a enter chamber 20 slightly spaced from the entrance of branch tubes 21b into chamber 20.

Between the entrances of tubes 21a and tubes 21b, there is a flow partition 57 sealing the space between the outer cylinder 30 and the inner cylinder 29 for the the sealing means is provided by an elastomeric tube 58 positioned in a slot in the barrier 57.

In the embodiment illustrated in FIGS. 10 and 11, it is particularly desirable for the tail extension 31 of the inner cylinder 29 to extend all the way to the slice 24 to maintain separation of the two different paper stocks until they are deposited upon the forming surface of the papermaking machine. With this arrangement, paper products can be produced having different properties on each side. However, the tail extension 31 could be terminated much closer to-the inner cylinder 29, as illustrated in FIG. 11, particularly if complete stratification of the two paper stocks was not necessary.

In FIG. 10, separation blade 56 is shown pivotally connected through pin to the tail extension 31. The pivotable separation blade 56 allows maintenance of equal sized channels for both flow streams at the slice when nozzle 23 adjustments are made to increase or decrease paper stock velocity. Adjustment of the pivotable separation blade 56 can be made through lever 63 connected to the blade 56.

FIG. 12 illustrates an embodiment of the invention which allows deposition of three or more stratified layers of different paper stock. This embodiment differs from the embodiment illustrated in FIGS. 10 and 11 in that it includes a conduit for flowing a third paper stock between the other two paper stocks and through the inner cylinder 29. FIG. 12 shows a box-like blending chamber 49 like that illustrated in FIGS. 7 through 9 passing through the chamber 20 and extending to the slice 24. The box-like blending chamber 49 can serve as the flow partition between the other two paper stocks entering the chamber 20 and also as the tail extension 31 separating the different paper stocks until they reach the slice 24.

In this embodiment illustrated by FIG. 12, the boxlike blending chamber 49 could be rigidly attached to both the outer cylinder 30 and the inner cylinder 29, in which case the positioning of the inner cylinder 29 within the outer cylinder 30 would not be adjustable. Or the box-like blending chamber could be slidable within the inner cylinder 29, in which case the inner cylinder 29 would be movable along the common plane of symmetry of the two cylinders.

FIG. 12 illustrates a box-like blending chamber 49, for the conduit for flowing the middle paper stock, but it is to be recognized that other means for flowing the stock through the chamber 20 could be employed with many of the advantages of the invention. For example, the middle paper stock could be flowed through the chamber 20 in a row of tubes and then into a wide conduit which separates the other two flows of stock downstream of the chamber 20. Also, it should be noted that the invention contemplates the use of more than one middle flow of paper stock, each flowing through adjoining conduits passing through the center of the chamber 20.

Substantial advantage can be gained from embodiments of the invention illustratedin FIGS. 10 and .11

even if flow is conducted from only one

header

22a or 22b, through one set of branch tubes 21a or 21b, and about the inner cylinder 29a and 21b in only one direction. In fact it might be desired to construct a chamber which would perform only this function. Such a construction is illustrated in FIG. .13, where the chamber 20 is one-half of an outer cylinder 30 and one-half of an inner cylinder 29. The inner member 29 is movable along bottom plate 60-to vary the flocculation pattern of the flowing paper stock. The adjustments can be provided by the arrangement illustrated by FIG. 4.

Throughout the description of the preferred embodiments of the invention (with the exception of FIG. 13), the inner and outer cylinders of the paperstock conditioning chamber 20 are described as cylinders modified on the downstream sides. It is to be recognized that some modification to the shapecould be made and still j 1 I retain some features of the invention, For example, the inner cylinder could be a true cylinder. Also, the cylindrical part of both the inner and outer cylinders could vary from a true cylindrical shape. However, it will be apparent to those skilled in the art that the described shapes of the preferred embodiments have advantages over other shapes because of the construction advantages of basically using readily availabletubular shapes, among other advantages.

We claim:

1. lnan apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the-paper stock and producing uniform velocity profile of the paper stock across the width'of the forming surface, said chamber comprising:

inlet means for flowing the paper stock into said chamber, said inlet means comprising a plurality of equal-sized, equally spaced conduits;

outlet means joining to the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface; and

wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved planes spaced apart from each other, a portion of said inner surface facing said inlet means at an abrupt angle to form an impingement surface, said inner surface in said chamber being adjustable with respect to said outersurfaceto vary said spacing in the direction of flow of the paper stock through said chamber, whereby the velocity of the paper stock varies as it flows through said chamber.

2. In an apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock and producing uniform velocity profile of the paper stock across the width of the forming surface, said chamber comprising:

inlet means for flowing thepaper stock into said chamber, said inlet means comprising a plurality of equal sized, equally spaced conduits; outlet means joining to the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface; and wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved planes generally forming circular arcs and spaced apart from each other, a portion of said inner surface facing said inlet means at an abrupt angle to form an impingement surface, said inner and outer surfaces extending from said inlet means in two opposite directions to form two flow channels forthe paper stock flowing through said chamber, the two flow channels smoothly rejoining each other before or upon the paper stock being deposited on the forming surface.

3. Chamber as recited in claim 2, wherein said inner surface extending from said inlet means in two opposite directions joins again to form an inner flow control member disposed within said outer surface.

4. Chamber as recited in claim 3, wherein said spacing continuously varies through said chamber, whereby the velocity of the paper stock flowing through said chamber is continuously varied,

5. Chamber as recited in claim 4, wherein said spacing gradually varies.

6. Chamber as recited in claim 4, wherein said spacing increases in the direction of flow of said paper stock through said chamber.

7. Chamber as recited in claim 4, wherein said spacing decreases in the direction of flow of said paper stock through said chamber.

8. Chamber as recited in claim 3, wherein said inner surface includes a separator tail extending downstream beyond said chamber for maintaining separation of the two streams of paper stock flowing through said two flow channels in said chamber. I

1 9. Chamber as recited in claim 3, wherein said inner surface is adjustable with respect to said outer surface to controllably create different flocculation characteristics for each of said two streams of paper stock flowing through said chamber 10. Chamber as recited in claim 3, wherein said inner flow control member is movable within said chamber tovary the position of said inner surface with respect to said outer surface.

11. Chamber as recited in claim 10, wherein said outer and inner surfaces are symmetrical about an axis passing through said inlet means and said outlet means, and said inner flow control member is movable towards or away from said inlet means along said axis of symmetry.v

12. Chamber as recited in claim 2, wherein said inlet means includes means for flowing two distinct flows of paper stocks into said chamber, each of said distinct flows flowing in opposite directions around said inner surface, and said chamber further includes a flow separation member preventing said distinct flows from com municating with each other at the inlet of said chamber.

13. Chamber as recited in claim 12, wherein the ratio of flow area in said blending chamber at the inlet means to the flow area of all of said plurality of conduits is in the range from about 1.1 to aboutl.7.

14. Chamber as recited .in claim .12, wherein said inner surface includes a separator tail extending downstream from said chamber for maintaining separation of said distinct flows 15. Chamber as recited in claim 14, wherein said separator tail extends to the flow nozzle exit where the paper stock is deposited upon the forming surface of the papermaking machine.

16. Chamber as recited inclaim 12, including means for conducting one or more inner streams of paper stock through said inner surface and between said two distinct flows of paper stock.

17. Chamber as recited in claim 16, including separator means for maintaining separation of said inner streams of paper stock from said distinct flows until said paper stock is deposited upon the forming surface of a papermaking machine.

18. Chamber as recited in. claim 16, wherein said inner surface is movable with respect to saidouter surface for varying the position of said inner surface with respect to said outer surface.

19. Apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, comprising 1 a paper stock delivery pipe for receiving paper stock from a conduit, said delivery pipe extending across at least a portion of the width of the papermaking machine,

an elongated outer flow control member comprising walls defining an elongated chamber having an elongated outlet opening extending along at least a portion of one side thereof. and a plurality of equal-sized, equally spaced inlet openings passing through said walls generally opposite said elongated outlet opening,

plurality of lateral conduits communicating with said delivery pipe and said chamber through said inlet openings and adapted to introduce paper stock from said delivery pipe into said chamber, an elongated inner flow control member disposed within said chamber with a portion facing said inlet openings at an abrupt angle to form an impingement surface for the paper stock, said inner flow control member forming a plurality of flow paths between said inlet openings and said elongate outlet opening, each of said'flow paths having a relatively large width-to-thickness ratio, and said outer flow control member walls joining the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface.

20. Apparatus according to claim 19, wherein said inner flow control member is adjustable with respect to said outer flow control member to vary the spacing between said inner flow control member and said inlet openings.

21. Apparatus according to claim 19, wherein the ratio of the combined cross-sectional area of said lateral conduits to the combined cross-sectional areas of the first portion of said flow paths is from about 1.1 to about 1.7.

22. In an apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock and'producing uniform velocity profile of the paper stock across the width of the forming surface, said chamber comprising:

inlet means for flowing the paper stock into said chamber;

outlet means joining to the flow nozzle for smoothly flowing the paper, stock uninterrupted from said chamber to the forming surfacej wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved planes generally forming circular arcs and'spaced apart from each other, a portion of said inner surface facing said outlet means at an abrupt angle to form an impingement surface; j

said inlet means includes a plurality of equal-size conduits equally spaced along said chamber generally transversely to the direction of flow of the paper stock, whereby the paper stock enters said chamber in a plurality of streams and the streams merge upon impingement with said impingement surface; and 1 the ratio of flow area of said chamber at said impingement surface to the flow area of said plurality of conduits is in the range of from about 1.1 to about 1.7.

23. Chamber as recited in claim 22, wherein said ratio is of the order of 1.5.

24. Chamber as recited in claim 22, including flow barriers between said conduits to reduce interference from the flow of said paper stock from one of said conduits with the flow from other conduits.

25. In an apparatus for conditioning paper stock flowing througha flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock, said chamber comprising:

inlet means for flowing the paper stock into said chamber, said inlet means. comprising a plurality of equal-sized, equally spaced conduits;

outlet means joining to the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface;

wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defming curved planes generally forming circular arcs and spaced apart from each other, a portion of said inner surface racing said outlet means at an abrupt angle to form an impingement surface and, said inner surface being adjustable with respect to said outer surfaceto vary the spacing between said-surfaces; said inlet means includes a box-like blending chamber connecting said plurality of conduits with said chamber for controlling flocculation of the paper I stock, said blending chamber being defined'by wall means including top and bottom walls, side walls, and an end wall, and said blending chamber receiving paper stock from said plurality of conduits through one wall thereof in a flow direction substantially normal to the opposite wall of said blending chamber, and the ratio of the flow area in said blending chamber measured at the location where said plurality of conduits enter said blending chamber to the total flow area of said plurality of con duits is in the range from about 1.1 to about 1.7.

26. In an apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock and producing uniform velocity profile of the paper stock across the width of said chamber, said chamber comprising:

inlet means for flowing the paper stock into said chamber, said inlet means comprising a plurality of equalsized, equally spaced-conduits;

outlet means for. smoothly flowing the paper stock uninterrupted from said chamber to'tlie forming surface; wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved-planes generally forming circular arcs and spaced apart from each other, a portion of said inner surface facing said inlet means at an abrupt angle to form an impingement surface; and

adjusting means for moving said inner surface within said chamber to vary the spacing between said inner surface and said outer surface and the distance of said impingement surface from saidinlet means.

27. Method of conditioning flowing paper stock prior to being deposited on the forming surface of a papermaking machine, comprising:

flowing said paper stock in a plurality of equally spaced apart, discrete streams having substantially equalflow velocity; flowing all of said paper stock againstan impingement surface aligned at an abrupt angle to the di-' rection of flow of said paper stock to disperse said paper stock; abruptly changing the direction of flow of said paper A stock to approximately parallel said impingement surface; flowing said paper stock in a smooth arcuate path; varying the flow velocity of said paper stock as it flows through said arcuate path to control flocculation of the paper stock; and

smoothly flowing said paper stock uninterrupted I flowing all of said paper stock against an impingement surface aligned at an abrupt angle to the direction of flow of said paper stock to disperse said paper stock;

' abruptly changing the direction of flow of said paper stock to two streams initially flowing in directions approximately parallel to said impingement surface and opposite to each other;

flowing each of said two streams in a smooth arcuate path; and smoothly flowing said paper stock uninterrupted from said arcuate path to the forming surface.

29. Method as recited in claim 28, wherein said two streams are smoothly brought back into contact with each other prior to being deposited on said forming surface.

v 30. Method as recited in claim 29, wherein said two streams remain substantially stratified after being brought back into contact with each other..

31. Method as recited in claim 28, including the step of varying the flow velocity of each of said streams as they flow through said arcuate paths. I

32. Method as recited in claim 31, wherein variation of said flow speed of each stream of paper stock is different from the other, whereby said flocculation charcrete streams into a thin wide stream having substantially uniform flow velocity across its width;

flowing said thin wide stream immediately after impingement against said surface of said box-like blending chamber at a flow velocity within the range of from about 0.6 to about 0.9 times the flow velocity of said discrete streams;

flowing all of said thin wide stream against a second impingement surface aligned at an abrupt angle to the direction of flow of said thin wide stream; abruptly changing the direction of flow of said thin wide stream to approximately parallel said second impingement surface; flowing said thin wide stream in a smooth arcuate path; varying the velocity of the thin wide stream as it flows through said arcuate path; and smoothly flowing said paper stock uninterrupted from said arcuate path to the forming surface. 39. Method of conditioning flowing paper stock prior I to being deposited upon the forming surface of a paperacteristics of eachstream of said paper stock is ,differ- I ent from the other. I

33. Method as recited in claim 31, wherein said flow velocity of each of said streams is decreased.

34. Method as recited in claim 31, wherein Said flow velocity of each of said streams is increased.

35. Method as recited in claim 28, wherein each of said'plurality of discrete streams are shielded from influence'by the other discrete streams. I

36. Method as recited in claim 28, wherein the ratio of the flow velocity of said paper stock in said plurality of discrete streams to the flow velocity of said paper stock initially after'being flowed against said impingement surface is in the range of from about 1.1 to about 37. Method as recited in claim 36, wherein said ratio is of the order of 1.5.

making machine, comprising; I

flowing a first and second paper stock in first and second pluralities of equally spaced apart, discrete streams having substantially equal flow velocities;

flowing all of said first paper stock'against an impingement surface aligned at an abrupt angle to the direction of flow of said first paper stock todisperse said first paper stock; flowing all of said second paper stock against an impingernent surface aligned at an abrupt angle, to the direction of flow of said second paper stock to disperse said second paper stock;- abruptly changingthe direction of flow of said first paper stock and said second paper stock to approximately parallel said impingement surface in directions generally opposite to each other; flowing said first and second paper stocks in smooth arcuate paths which smoothly bring said first and second paper stocks together; and

smoothly flowing said paper stock uninterrupted from said arcuate paths to the forming surface.

40. Method as recited in claim 39, including the step of v varying the flow velocities of said first and second paper stocks as they flow through said arcuate paths, to control flocculation of said first and second paper stock. I

41. Method as recited in claim 39,wherein said first and second paper stocks are flowed separately until being deposited on said forming surface of a papermaking machine. a

42., Methodas recited in claim 39, further including the step of flowing at least one additional paper stock between said first and second paper stocks.

, 43. Method as recited in claim 42, wherein all of said paper stocks are brought into contact with each other upon being deposited on said forming surface of a papermaking machine.

Claims

2. In an apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock and producing uniform velocity profile of the paper stock across the width of the forming surface, said chamber comprising: inlet means for flowing the paper stock into said chamber, said inlet means comprising a plurality of equal sized, equally spaced conduits; outlet means joining to the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface; and wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved planes generally forming circular arcs and spaced apart from each other, a portion of said inner surface facing said inlet means at an abrupt angle to form an impingement surface, said inner and outer surfaces extending from said inlet means in two opposite directions to form two flow channels for the paper stock flowing through said chamber, the two flow channels smoothly rejoining each other before or upon the paper stock being deposited on the forming surface.
3. Chamber as recited in claim 2, wherein said inner surface extending from said inlet means in two opposite directions joIns again to form an inner flow control member disposed within said outer surface.
4. Chamber as recited in claim 3, wherein said spacing continuously varies through said chamber, whereby the velocity of the paper stock flowing through said chamber is continuously varied.
5. Chamber as recited in claim 4, wherein said spacing gradually varies.
6. Chamber as recited in claim 4, wherein said spacing increases in the direction of flow of said paper stock through said chamber.
7. Chamber as recited in claim 4, wherein said spacing decreases in the direction of flow of said paper stock through said chamber.
8. Chamber as recited in claim 3, wherein said inner surface includes a separator tail extending downstream beyond said chamber for maintaining separation of the two streams of paper stock flowing through said two flow channels in said chamber.
9. Chamber as recited in claim 3, wherein said inner surface is adjustable with respect to said outer surface to controllably create different flocculation characteristics for each of said two streams of paper stock flowing through said chamber.
10. Chamber as recited in claim 3, wherein said inner flow control member is movable within said chamber to vary the position of said inner surface with respect to said outer surface.
11. Chamber as recited in claim 10, wherein said outer and inner surfaces are symmetrical about an axis passing through said inlet means and said outlet means, and said inner flow control member is movable towards or away from said inlet means along said axis of symmetry.
12. Chamber as recited in claim 2, wherein said inlet means includes means for flowing two distinct flows of paper stocks into said chamber, each of said distinct flows flowing in opposite directions around said inner surface, and said chamber further includes a flow separation member preventing said distinct flows from communicating with each other at the inlet of said chamber.
13. Chamber as recited in claim 12, wherein the ratio of flow area in said blending chamber at the inlet means to the flow area of all of said plurality of conduits is in the range from about 1.1 to about 1.7.
14. Chamber as recited in claim 12, wherein said inner surface includes a separator tail extending downstream from said chamber for maintaining separation of said distinct flows of paper stock beyond said chamber.
15. Chamber as recited in claim 14, wherein said separator tail extends to the flow nozzle exit where the paper stock is deposited upon the forming surface of the papermaking machine.
16. Chamber as recited in claim 12, including means for conducting one or more inner streams of paper stock through said inner surface and between said two distinct flows of paper stock.
17. Chamber as recited in claim 16, including separator means for maintaining separation of said inner streams of paper stock from said distinct flows until said paper stock is deposited upon the forming surface of a papermaking machine.
18. Chamber as recited in claim 16, wherein said inner surface is movable with respect to said outer surface for varying the position of said inner surface with respect to said outer surface.
19. Apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, comprising a paper stock delivery pipe for receiving paper stock from a conduit, said delivery pipe extending across at least a portion of the width of the papermaking machine, an elongated outer flow control member comprising walls defining an elongated chamber having an elongated outlet opening extending along at least a portion of one side thereof, and a plurality of equal-sized, equally spaced inlet openings passing through said walls generally opposite said elongated outlet opening, a plurality of lateral conduits communicating with said delivery pipe and said chamber through said inlet openings and adapted to introduce paper stock from said delivery pipe into said chamber, an elongated inner flow control member disposed within said chamber with a portion facing said inlet openings at an abrupt angle to form an impingement surface for the paper stock, said inner flow control member forming a plurality of flow paths between said inlet openings and said elongate outlet opening, each of said flow paths having a relatively large width-to-thickness ratio, and said outer flow control member walls joining the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface.
20. Apparatus according to claim 19, wherein said inner flow control member is adjustable with respect to said outer flow control member to vary the spacing between said inner flow control member and said inlet openings.
21. Apparatus according to claim 19, wherein the ratio of the combined cross-sectional area of said lateral conduits to the combined cross-sectional areas of the first portion of said flow paths is from about 1.1 to about 1.7.
22. In an apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock and producing uniform velocity profile of the paper stock across the width of the forming surface, said chamber comprising: inlet means for flowing the paper stock into said chamber; outlet means joining to the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface; wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved planes generally forming circular arcs and spaced apart from each other, a portion of said inner surface facing said outlet means at an abrupt angle to form an impingement surface; said inlet means includes a plurality of equal-size conduits equally spaced along said chamber generally transversely to the direction of flow of the paper stock, whereby the paper stock enters said chamber in a plurality of streams and the streams merge upon impingement with said impingement surface; and the ratio of flow area of said chamber at said impingement surface to the flow area of said plurality of conduits is in the range of from about 1.1 to about 1.7.
23. Chamber as recited in claim 22, wherein said ratio is of the order of 1.5.
24. Chamber as recited in claim 22, including flow barriers between said conduits to reduce interference from the flow of said paper stock from one of said conduits with the flow from other conduits.
25. In an apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock, said chamber comprising: inlet means for flowing the paper stock into said chamber, said inlet means comprising a plurality of equal-sized, equally spaced conduits; outlet means joining to the flow nozzle for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface; wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved planes generally forming circular arcs and spaced apart from each other, a portion of said inner surface facing said outlet means at an abrupt angle to form an impingement surface and, said inner surface being adjustable with respect to said outer surface to vary the spacing between said surfaces; said inlet means includes a box-like blending chamber connecting said plurality of conduits with said chamber for controlling flocculation of the paper stock, said blending chamber being defined by wall means including top and bottom walls, side walls, and an end wall, and said blending chamber receiving paper stock from said plurality of conduits through one wall thereof in a flow directIon substantially normal to the opposite wall of said blending chamber, and the ratio of the flow area in said blending chamber measured at the location where said plurality of conduits enter said blending chamber to the total flow area of said plurality of conduits is in the range from about 1.1 to about 1.7.
26. In an apparatus for conditioning paper stock flowing through a flow nozzle to the forming surface of a papermaking machine, a chamber for controlling flocculation of the paper stock and producing uniform velocity profile of the paper stock across the width of said chamber, said chamber comprising: inlet means for flowing the paper stock into said chamber, said inlet means comprising a plurality of equal-sized, equally spaced conduits; outlet means for smoothly flowing the paper stock uninterrupted from said chamber to the forming surface; wall means for confining the paper stock flowing through said chamber to a desired path, said wall means including an inner surface and an outer surface, said surfaces defining curved planes generally forming circular arcs and spaced apart from each other, a portion of said inner surface facing said inlet means at an abrupt angle to form an impingement surface; and adjusting means for moving said inner surface within said chamber to vary the spacing between said inner surface and said outer surface and the distance of said impingement surface from said inlet means.
27. Method of conditioning flowing paper stock prior to being deposited on the forming surface of a papermaking machine, comprising: flowing said paper stock in a plurality of equally spaced apart, discrete streams having substantially equal flow velocity; flowing all of said paper stock against an impingement surface aligned at an abrupt angle to the direction of flow of said paper stock to disperse said paper stock; abruptly changing the direction of flow of said paper stock to approximately parallel said impingement surface; flowing said paper stock in a smooth arcuate path; varying the flow velocity of said paper stock as it flows through said arcuate path to control flocculation of the paper stock; and smoothly flowing said paper stock uninterrupted from said arcuate path to the forming surface.
28. Method of conditioning flowing paper stock prior to being deposited on the forming surface of a papermaking machine, comprising: flowing said paper stock in a plurality of equally spaced apart, discrete streams having substantially equal flow velocity; flowing all of said paper stock against an impingement surface aligned at an abrupt angle to the direction of flow of said paper stock to disperse said paper stock; abruptly changing the direction of flow of said paper stock to two streams initially flowing in directions approximately parallel to said impingement surface and opposite to each other; flowing each of said two streams in a smooth arcuate path; and smoothly flowing said paper stock uninterrupted from said arcuate path to the forming surface.
29. Method as recited in claim 28, wherein said two streams are smoothly brought back into contact with each other prior to being deposited on said forming surface.
30. Method as recited in claim 29, wherein said two streams remain substantially stratified after being brought back into contact with each other.
31. Method as recited in claim 28, including the step of varying the flow velocity of each of said streams as they flow through said arcuate paths.
32. Method as recited in claim 31, wherein variation of said flow speed of each stream of paper stock is different from the other, whereby said flocculation characteristics of each stream of said paper stock is different from the other.
33. Method as recited in claim 31, wherein said flow velocity of each of said streams is decreased.
34. Method as recited in claim 31, wherein said flow velocity of each of said streams is increased.
35. Method as recited in claIm 28, wherein each of said plurality of discrete streams are shielded from influence by the other discrete streams.
36. Method as recited in claim 28, wherein the ratio of the flow velocity of said paper stock in said plurality of discrete streams to the flow velocity of said paper stock initially after being flowed against said impingement surface is in the range of from about 1.1 to about 1.7.
37. Method as recited in claim 36, wherein said ratio is of the order of 1.5.
38. Method of conditioning flowing paper stock prior to being deposited upon the forming surface of a papermaking machine, comprising: flowing paper stock in a plurality of equally spaced apart discrete streams having substantially equal flow velocity; impinging said discrete streams against a surface of a box-like blending chamber to combine said discrete streams into a thin wide stream having substantially uniform flow velocity across its width; flowing said thin wide stream immediately after impingement against said surface of said box-like blending chamber at a flow velocity within the range of from about 0.6 to about 0.9 times the flow velocity of said discrete streams; flowing all of said thin wide stream against a second impingement surface aligned at an abrupt angle to the direction of flow of said thin wide stream; abruptly changing the direction of flow of said thin wide stream to approximately parallel said second impingement surface; flowing said thin wide stream in a smooth arcuate path; varying the velocity of the thin wide stream as it flows through said arcuate path; and smoothly flowing said paper stock uninterrupted from said arcuate path to the forming surface.
39. Method of conditioning flowing paper stock prior to being deposited upon the forming surface of a papermaking machine, comprising; flowing a first and second paper stock in first and second pluralities of equally spaced apart, discrete streams having substantially equal flow velocities; flowing all of said first paper stock against an impingement surface aligned at an abrupt angle to the direction of flow of said first paper stock to disperse said first paper stock; flowing all of said second paper stock against an impingement surface aligned at an abrupt angle to the direction of flow of said second paper stock to disperse said second paper stock; abruptly changing the direction of flow of said first paper stock and said second paper stock to approximately parallel said impingement surface in directions generally opposite to each other; flowing said first and second paper stocks in smooth arcuate paths which smoothly bring said first and second paper stocks together; and smoothly flowing said paper stock uninterrupted from said arcuate paths to the forming surface.
40. Method as recited in claim 39, including the step of varying the flow velocities of said first and second paper stocks as they flow through said arcuate paths, to control flocculation of said first and second paper stock.
41. Method as recited in claim 39, wherein said first and second paper stocks are flowed separately until being deposited on said forming surface of a papermaking machine.
42. Method as recited in claim 39, further including the step of flowing at least one additional paper stock between said first and second paper stocks.
43. Method as recited in claim 42, wherein all of said paper stocks are brought into contact with each other upon being deposited on said forming surface of a papermaking machine.