US2718824A - Headbox for paper making machine - Google Patents

Description

Sept. 27, 1955 L. HORNBOSTEL HEADBOX FOR PAPER MAKING MACHINE Filed Oct. 25 195] m g i [r1 YE 2*2 TUF IL 0Y0 [702M905 7'51.

Unite rates Patent 2,718,824 Patented Sept. 2'7, 1%55 HEADBU'X FGR PAPER MAKENG MAQHINE Lloyd Hornbostel, Beloit, Wis., assignor to Beloit Iron Works, fieloit, Wis., a corporation of Wisconsin Application October 25, 1951, Serial No. 253,035

a lairns. (Cl. 92-44 This invention relates to improvements in paper machine stock inlets, and more particularly, relates to an improved forming zone and slice for stock inlets and includes an improved method of controlling stock feed.

In a stock inlet for a paper machine, the slice outlet should flow paper stock onto the forming surface of the machine in sheet-like form having even thickness or volume across the width of the surface and advancing at a controlled rate of speed. The advancing sheet of stock should be free from cross or eddy currents and have true directional flow relationship with the travel of the forming surface to insure equal stock velocity and distribution at every part of the surface.

Since the head pressure on paper stock fed through a slice in high speed machines is quite substantial, the problem of designing a suitable slice is essentially hydraulic in character, although other factors may be involved to some degree in the projection of the desired sheet of stock onto the wire.

The relationship between the velocity of stock leaving the slice and the speed of the forming surface or wire is one of the most important factors of sheet formation on medium and high-speed machines. When the speed of the wire is approximately at or slightly greater than the speed of the stock, the fibers are drawn in a horizontal plane and produce a well formed sheet. If the stock speed is appreciably greater than that of the wire, however, the fibers will have a tendency to be drawn at right angles to the plane of the wire, and the result is a poorly formed paper sheet. Further, there is a tendency to obtain a cylinder-type formation if the forming Wire speed is substantially greater than that of the stock.

Moreover, a certain amount of turbulence is necessary in the stock as it is deposited upon the forming wire in order to obtain completely random disposition of the fibers in the stock as the stock arrives in the forming area or zone, namely, that area just prior to and including the area on the wire at which a suflicient amount of water has left the stock to permit initial formation of a paper sheet.

According to this invention the desired sheet like feed of stock to the forming wire is obtained by feeding the stock between spaced rotating rolls defining the slice outlet or feed nozzle therebetween. The rolls control turbulence of the stock and can assist drainage through the wire by pushing the stock through a converging downwardly inclined path. The rolls can be rotated in the same or opposite directions and at the same or different speeds. The upper roll will gauge or meter the stock.

It is then an object of this invention to provide improved methods and apparatus for controlling flow of stock onto the forming surface of a paper machine.

It is a further object of the instant invention to provide an improved method and apparatus for supplying a uniform fluid flowing sheet of paper stock to a forming wire.

It is still a further object of the instant invention to provide a stock inlet which will push stock onto the forming wire in sheet-like form having a desired directional flow relative to the travel of the forming wire.

Another and important object is to roll paper stock onto the forming wire.

It is another important object of the instant invention to provide an improved stock inlet for controlling the turbulence of stock flow in the forming zone.

Other objects, features and advantages of this invention will become apparent to one skilled in the art from the following description of the embodiment illustrated in the accompanying drawings.

On the drawings:

Figure 1 is an elevational diagrammatic view of a preferred embodiment of the present invention, showing parts in vertical section; and

Figure 2 is an elevational diagrammatic view of another preferred embodiment of the invention, with parts shown in vertical section.

As shown on the drawings:

Referring to Figure l, the reference numeral 10 represents the looped forming wire of a Fourdrinier paper making machine. The wire is trained about a breast roll 11 and has its upper run supported on a table roll 12 spaced in front of the breast roll 11. The breast roll 11 and the table roll 12 are mounted for free rotation on suitable supports (not shown) and have the general sizes and shapes of the rolls ordinarily used for those purposes in a paper machine. They are preferably imperforate.

A stock feed device or inlet box 13, having a rigid floor or base 14 with an apron 15 projecting therefrom to the top peripheral portion of the breast roll 11, is mounted immediately behind the wire 10. The apron 15 is tapered at its forward end and terminates just behind the top center of the breast roll so that the stock flowing thereover from the stock inlet box 13 may flow onto the upper run of the forming wire 10 while the wire is supported by the breast roll 11 in a substantially horizontal plane as it passes over the top center of the roll behind the top peripheral portion.

The stock inlet box 13 also has a front wall 16, side walls 17, an end wall (not shown) and a top wall 18. Such walls cooperate with the floor 14 to define the stock pond or chamber wherein stock is maintained at a predetermined level, for example, at the level designated by the reference numeral 19. The forward wall 16 of the stock inlet box 13 overlies and cooperates with the apron 15 so as to define a generally rectangular outlet 20 at the forward bottom end of the stock inlet box 13.

Mounted on the inside of the inlet box 13 at the mouth of the outlet 20 is a rectifier roll 21. The rectifier roll 21 is journaled for free rotation at opposite ends thereof in the side walls 17 and extend across the width of the inlet box 13 (and across the mouth of the outlet 20). The rectifier roll 21 may be driven by a suitable means (not shown).

The force driving the stock through the outlet 20 is principally a hydraulic force exerted by the stock at the outlet 20. The hydraulic force is determined by the hydraulic head of stock in the inlet box 13 and by pressure on top of the stock.

As shown in Figure 1, the outlet 20 from the stock inlet box 13 is defined by the forward wall 16 and the apron 15. In addition, an impervious flexible sheet 22, suitably aflixed at its rear end to the bottom end of the forward wall 16 and extending downwardly and forwardly therefrom, overlies the apron 15 and cooperates therewith to form a restricted outlet chamber or spout. The forward end of the flexible sheet 22 is suitably mounted upon a fixed transverse beam member 23 in front of and gen erally parallel to the front wall 16 to extend across the full width of the inlet box 13. The non-porous flexible sheet 22, made of some water-tight material such as a flexible metal sheet, thus extends the full width of the stock inlet box 13 and forms a water-tight seal between the front Wall 16 and the support member 23.

Suitably mounted near the top of the support beam member 23 are a plurality of internally threaded vertical sleeves 24 (only one of which is shown). Mounted in each of such sleeves 24 is a vertical member 25 threadedly engaging the threads of the sleeve 24- and cooperating therewith for adjustable vertical movement of the member 25. The vertical movement of the member 25 may be effected by turning the screw head 26 mounted at the top of the member 25. The bottom end of the member 25 is suitably anchored to the flexible member 22 at 27, for example, by a pivot coupling. Upward and downward motion of the member 25 causes upward and downward motion of the flexible member 22 in the region near the connection 27, such as is shown by the dotted lines in Figure 1.

The members 25 are so mounted at regular intervals across the entire width of the sheet 22. It is apparent that the level of each of the members 25 is independently adjustable and, since adjustment of the position of the member 25 results in adjustment of the height of the sheet 22, the contour of the outlet chamber or spout is controlled.

The connection points 27 for the adjusting members 25 lie substantially directly above the forward edge of the apron 15, so that maximum deflection of the flexible sheet 22 may be accomplished above the forward edge of the apron at the entrance to a forming zone section 28. The forming zone 28 is a zone enclosing that area of the forming wire from the point at which the stock is received upon the forming wire to a point at which the fibers in the stock have lost a sufficient amount of water so as to accomplish initial formation of the paper sheet upon the forming wire. The flow of stock in the forming zone is of critical importance in the formation of paper of suitable quality.

A second imperforate breast roll or metering roll 29 is mounted above and closely adjacent to the forming wire 10 in advance of the breast roll 11 for metering the flow of stock between the roll 29 and the wire 10. The second breast roll 29 is so mounted that a line drawn between its center and the center of the breast roll 11 forms an angle with a vertical line. This angle is preferably about 45. The bottom peripheral portion of the second breast roll 29 lies closely adjacent to the forming wire 10 preferably below the top peripheral portion of the breast roll 11. The forming wire supported by the spaced breast roll 11 and table roll 12 assumes a catenary shape under the roll 29.

The bottom peripheral portion of the upper or second breast roll 29 extends below the top of the breast roll 11 for about one-quarter to one-half of its radius. The upper breast roll 29 is larger than the roll 11 being approximately one and a half times the diameter of the lower breast roll 11. The breast roll 29 is rotatably mounted on suitable adjustable supports (not shown); and preferably driving means (not shown) of a suitable nature are cooperatively connected to the top breast roll 29 in order to selectively rotate the roll 29 in either direction (as shown by the two-headed arrow) and at variable speeds.

The fixed support 23 has a bottom shoe-like member 30 which forms a liquid seal between the flexible member 22 and the top breast roll 29. Like the flexible sheet 22, the bottom member 30 of the fixed support 23 extends the, full length of the breast roll 11 and'the breast roll 29. The member 39 is curved downwardly from the line along which the flexible sheet is mounted thereon to a line along which it lies closely adjacent to the breast roll 29 and it is generally tapered thereat so that it directs the flow of stock approximately tangentially against the periphery of the upper breast roll 29.

It should be noted also that the curve formed by the surface of the bottom member 30 adjacent the flowing stock is such that the cross-sectional area of the forming zone 28 is progressively decreased from the region adjacent to the top peripheral portion of the breast roll 11 to the region wherein the stock initially contacts the top breast roll 29; and the cross-sectional area of the forming zone is progressively decreased from there as the breast roll 29 and the forming Wire 10 come increasingly closer together. The breast roll 29 may be prepared of substantially the same material and has substantially the same design as that of the breast roll 11, but it is adjustably mounted so that its distance from the wire 10 may be varied.

In the operation of the instant apparatus the stream of dilute stock is delivered by way of the stock inlet box 13 and outlet 20 to the forming zone 28 at a predetermined velocity. Such velocity may be controlled by the total hydraulic stock head which, in turn, is controlled by suitable means for maintaining a predetermined head of stock in the inlet box and/or by a suitable means for maintaining a predetermined air pressure against the stock in the inlet box 13. In addition, the rate of flow of stock. at various points along the outlet 20 may be controlled by coaction between the flexible sheet 22 and the adjusting members 25.

The stock flows from the outlet chamber onto a top peripheral region of the breast roll 11 and thence into the forming zone 23. The velocity at which the stock flows onto the forming wire 10 which is mounted on the breast roll 11 may or may not be the same speed as that of the forming wire 1t As the stock passes into the forming zone 28, the forming wire 10 over which the stock flows travels a short distance on the periphery of the breast roll 11 and then separates therefrom and travels downwardly and across to a first table roll 12. The forming wire is otherwise unsupported in its travel from its departure from the periphery of the press roll 11 to its contact with the table roll 12.

It is, of course, apparent that the water in the stock may pass freely through the forming wire 10 throughout the unsupported area of the forming wire 10. Accordingly, as the stock flows into the forming zone and onto the unsupported portion of the forming wire 10, the actual velocity of the water in the stock need not be appreciably slowed down since the water may pass directly downwardly and through the forming wire 10. The consistency of the stock immediately above the forming wire 10, however, increases rapidly in the forming zone as the stock approaches the narrow passage or slice defined by the upper breast roll 29 and the forming wire 10. Preferably, a baflie or deflector 31 is positioned below (but not supporting) the forming wire 10 in the region near the table roll 12 so as to deflect the flow of water passing through the forming wire downwardly.

The rate in which the overall stock consistency increases in the forming zone 28 may be adjusted by adjusting the design and arrangement of the breast rolls 11 and 29 and the forming wire 10. For example, it is possible to arrange a decrease in cross-sectional area of the forming zone which results in a predetermined consistency increase rate at any desired predetermined flow rate. A relatively small upper breast roll 29 would result in a rather rapid decrease in the cross-sectional area of the forming zone from the point at which the stock came into contact with the breast roll 29. On the other hand, a very large upper breast roll 29 in combination with a forming wire traveling in a relatively full catenary curvilinear path would result in a forming zone in which the cross-sectional area decreased rather slowly.

The instant invention also involves the use of additional control means which may be used to effectively obtain precision control of the stock. One of such control means, as has already been mentioned, involves the use of a plurality of adjusting members 25 for adjusting the thickness of the stock outlet 20 at various regions across the width of the stock outlet 20. The advantage of such control means can be best appreciated by consideraeither direction.

tion of the theory of fluid film. It is generally recognized that in a fluid flowing along the surface of a conduit there are a series of superimposed socalled films of the fluid adjacent the walls of the conduit. The film nearest the wall of the conduit is practically a static film and the film adjacent thereto is only slightly in motion. The film adjacent to the latter film moves slightly more rapidly, and so on, until the portions of the fluid in the central portion of the duct flow at a relatively rapid rate. It can thus be seen that in fluid flowing through a conduit or duct such as the outlet chamber there is tendency for the fluid to exert a greater pressure and to flow more rapidly in the central portion of the duct away from the walls thereof.

The rectifier roll 21 can, of course, be designed to correct that tendency toward lack of uniform flow in the duct at a given flow rate, but the rectifier roll is usually insufficiently flexible in the manner in which it controls the uniformity to give optimum control at all flow rates. In the instant apparatus the various adjustable members 25 may be used to make corrections in the thickness of the outlet chamber so as to compensate adjustably for any particular flow rate.

An additional very important control means for use in the instant invention is based upon the rotation of the top breast roll or metering roll 29 at variable speeds in Since the turbulence of flow in fluid is based upon the velocity differences between the respective fluid films, this control will regulate turbulence. In the instant apparatus in the forming zone, one conduit surface is the moving wire (having a formed paper web thereon) and the other conduit surface is the periphery of the breast roll 29. If the breast roll 29 were caused to rotate so that its periphery moves in the same direction and at approximately the same velocity as that of the forming wire 10, the walls of the conduit at the output of the forming zone would tend to create fluid films at the top and bottom of the outlet moving at substantially the same rate (and at a rate substantially in excess of the rate of a relatively static film normally adjacent a fixed conduit wall). The net result would be a very greatly increased tendency toward the production of streamline flow at the exit of the forming zone, since there would be a tendency to decrease any velocity differential between the flow of fluid at the walls of the conduit and the flow of fluid in the middle of the conduit.

On the other hand, the turbulence of flow which may be desired in any particular operation may be very accurately controlled by controlling the speed and direction of rotation of the top breast roll 29. For example, if the top breast roll 29 were rotated in a direction opposite to the direction of travel of the forming wire and at a relatively high speed, it is clear that the turbulence of flow in the forming zone 28 would be very substantially increased (over that obtained under the conditions described in the foregoing paragraph).

Also, the hydraulic pressure head at the central portion of the forming zone outlet may be varied appreciably by variations in the speed and direction of rotation of the top breast roll 29.

Moreover, since the top breast roll 29 does not actu ally carry the forming wire 10, the breast roll 29 may be crowned, so as to additionally compensate for the tendency toward higher flow rate and hydraulic pressure at the central portion of the forming zone outlet.

. Still another means available for adjusting the operation of the instant apparatus, resides in the availability to limited extent of centrifugal force for use in urging the flow of water through the forming wire 10. In other words, by adjustment of the relative position of the breast rolls 11 and 29 and the forming wire 10 passing therebetween, it is possible adjust the curvilinear path of travel taken by the forming wire 10 and thereby to adjust the more or less arcuate travel path of the stock in the forming zone. It is, of course, apparent that the sharper the U curve or the arc in which the stock travels in passing through the forming zone, the greater is the centrifugal force tending to force the water through the wire and the web or mat thereon.

Referring to Figure 2, wherein another preferred embodiment of the invention is shown, it can be seen that certain of the distinctive features of the arrangement shown in Figure 2 are substantially the same as those of the arrangement shown in Figure 1. Accordingly, those elements of the arrangement of Figure 2 which are substantially the same as the corresponding elements of the arrangement of Figure 1 have been designated by the same reference numeral (followed by the letter a).

For example, the forming wire 10a is trained about the press roll 11a and travels on a table roll 12a in substantially the same manner as was described in connection with Figure i. In like manner, the stock inlet box 1311 comprises a base member 14a forming the horizontal floor of the stock inlet box 13a and having an apron 15a forming an extended forward portion of the floor. The stock inlet box 13a also comprises a forward wall 16a, side walls 170, an end wall (not shown) and a top wall 18a, coopcrating as shown in connection with Figure 1.

The forward wall 16a of the stock inlet box 13a overlies and cooperates with the apron 15a so as to define a generally rectangular outlet 20a leading from the stock inlet box 13a. Mounted on the inside of the inlet box 13a near the mouth of the outlet 20a is a pair of rectifier rolls 32 and 33. The rectifier rolls 32 and 33, like the rectifier roll 21, are of the type ordinarily used in paper machines, being journaled for free rotation at opposite ends thereof in the side walls 17a and extending across the width of the inlet box 13a. The rectifier rolls 32 and 33 are driven by suitable means (not shown) and are provided with a plurality of graduated peripheral perforations (not shown), which diminish in capacity ordinarily in wardiy from the end of each of the rolls, so that a uniform flow rate along the entire length of each of the rolls may be maintained.

As can be seen from Figure 2, the rectifier rolls 32 and 33 are positioned one above the other so that they extend. upwardly (and angularly) the full height of the outlet Zila and the full angular distance from the stock inlet floor to the forward wall 16a near the outlet 20a. The rectifier rolls 32 and 33 also, of course, extend across the full width of the outlet 20a.

In addition, a stack of rectifier rolls, comprising a pair of rolls 34 and 35 (shown only partially) are positioned behind the rectifier rolls 32 and 33 in the stock inlet box 13a. The rectifier rolls 34 and 35, being so stacked one on top of the other, extend the full height of the stock in the inlet box 13a from the floor to just below the stock level 19a. The rectifier rolls 34 and 35 so positioned tend to effect uniformity in the flow of all the stock passing through the inlet box 13a, and cooperate with the rectifier rolls 32 and 33 to obtain optimum uniformity in the stock flow at the outlet 20a.

As hereinbefore mentioned, the force driving the stock through the outlet 20a is principally a hydraulic force exerted by the stock at the outlet 20a. The hydraulic force is determined by the hydraulic head of stock in the inlet box 13a (i. e., the stock level 19a, which is shown to be higher in Figure 2 than in Figure l), which in turn is the function of the rate in which the stock is pumped or flowed into the inlet box 13a. In the arrangement of Figure 2, it is also contemplated that suitable flow means (not shown), as well as suitable air pressure control means (not shown) may be used in controlling the total hydraulic head and thereby the flow rate.

As can be seen from Figure 2, the forward wall 16a is so positioned with respect to the apron 15a that it overlies substantially (slightly forward thereof) the forward tip of the apron 15. A line drawn between the forward edge of the apron 15a and the downward extremity of the forward wall 16a designates approximately the beginning of the forming zone 28a, which extends therefrom to the slice or narrow passageway formed between the upper press roll 29a and the forming wire 10a.

The downward extremity of the forward wall 16a is turned forwardly to form a shoe-like member 36, which functions much as the shoe-like member 30 of Figure 1 to form a liquid seal between the forward wall 16a and the top breast roll 29a.

Like the breast roll 29 of Figure 1, the breast roll 29a is mounted above and closely adjacent to the forming wire 10a forward or in advance of the breast roll 11a. However, unlike the breast roll 29 of Figure 1, the breast roll 29a cooperates directly with the forward wall 16a to form a liquid seal, and the apparatus of Figure 2 does not contain the additional control means involving the use of a plurality of adjusting members for adjusting the thickness of the stock outlet chamber at various regions across the width of the stock outlet chamber, such as is shown in Figure l.

The general size, shape and adjustable mounting means for the upper breast roll 2% are the same as those described hereinbefore in connection with the reast roll 29. In addition, it may be preferred to employ a substantially greater crown in the design of the roll 29a in order to additionally compensate for the tendency toward higher flow rate and hydraulic pressure at the central portion of the forming zone.

It can be seen from both Figures 1 and 2 that the upper reast roll is so positioned adjacent to the lower breast roll that the upper breast roll overlies partially the lower breast roll and, of course, overlies entirely the forming zone. In other words, the top breast roll, the bottom breast roll and the wire cooperate to define a forming chamber and a slice. The top breast roll also cooperates with a duct portion to form what amounts to the top side of the forming chamber, or at least the entrance thereto. The duct portion, which actually defines the inlet for the forming chamber, comprises the shoe-like member 30 (in Figure l) or the shoe-like member 36 (in Figure 2) each of which cooperates with the upper breast roll to form a water-tight seal.

It has been found that in order to obtain efiective operation of the forming wire in the instant apparatus, it is necessary that the upper breast roll be so positioned with respect to the lower breast roll that a line drawn through the center of each of the rolls is approximately from the vertical (i. e., the angle p, as shown in Figures 1 and 2 should be about 45).

Also, it is preferable that the upper breast roll be of such size and be so positioned that it overlies partially the lower breast roll.

By the use of the upper and lower breast roll arrangement employed in the instant invention it is possible to deflect the generally horizontal stock flow downwardly about 45 immediately after it is delivered onto the wire or into the forming zone. It has been found that it is necessary to deflect the stock flow downwardly at least about 45 in order to eflfectively remove the necessary amount of water to the forming wire in the relatively short distance which the forming wire may be unsupported in controlled operation of the machine.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the instant invention.

I claim as my invention:

1. In a machine for forming a paper web, a traveling forming wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming wire, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll, the bottom of said upper breast roll being beneath the top of the lower breast roll and in close-running slice-defining relation to said wire, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

2. In a machine for forming a paper web, a traveling forming wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming wire, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll, the bottom of said upper breast roll being beneath the top of the lower breast roll and in close-running slice-defining relation to said wire, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said duct also extending along the full width of the upper breast roll and having therein a plurality of independent means for selectively adjusting the eifective height of said duct at the rear of said upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

3. In a machine for forming a paper web, a traveling forming wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming wire, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll, the bottom of said upper breast roll being beneath the top of the lower breast roll and in close-running slice-defining relation to said wire, means for rotating said upper breast roll at a predetermined speed and in a predetermined direction, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

4. In a machine for forming a paper web, a traveling forming wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming wire, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll, the bottom of said upper breast roll being beneath the top of the lower breast roll and in close-running slice-defining relation to said wire, means for rotating said upper breast roll at a predetermined speed and in a predetermined direction, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said duct also extending along the full width of the upper breast roll and having therein a plurality of independent means for selectively adjusting the eifective height of said duct at the rear of said upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

5. In a machine for forming a paper web, a traveling forming wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming wire, a table roll beneath the forming wire in spaced forward relation to the lower breast roll, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll and between said lower breast roll and said table roll, the bottom of-said upper breast roll being beneath the top of the lower breast roll and in close-running slice-defining relation to said wire, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

6. In a machine for forming a paper web, a traveling forming wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming wire, a table roll beneath the forming wire in spaced forward relation to the lower breast roll, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll and between said lower breast roll and said table roll, the bottom of said upper breast roll being beneath the top of the lower breast roll and in closerunning slice-defining relation to said wire, means for rotating said upper breast roll at a predetermined speed and in a predetermined direction, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

7. In a machine for forming a paper web, a traveling forming wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming Wire, a table roll beneath the forming wire in spaced forward relation to the lower breast roll, a deflector beneath the forming wire and between said lower breast roll and said table roll for directing white water drained through the forming wire away from said table roll, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll and between said lower breast roll and said table roll, the bottom of said upper breast roll being beneath the top of the lower breast roll and in close-running slice-defining relation to said wire, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

8. In a machine for forming a paper web, a traveling forming Wire, a pair of breast rolls, one positioned above the other, the lower breast roll having said forming wire trained thereabout and rotating freely at the speed of said forming wire, the upper breast roll overlying partially the lower breast roll and partially an unsupported portion of said wire in advance of the lower breast roll, the bottom of said upper breast roll being beneath the top of the lower breast roll and in close-running slice-defining relation to said wire, said upper and lower breast rolls being so positioned that a plane drawn through the axes of said rolls forms a angle with a vertically extending radius of said lower breast roll, and a duct overlying and extending to a top peripheral portion of the lower breast roll and extending from the bottom to a rear peripheral portion of the upper breast roll, said breast rolls cooperating with said duct and said wire to define a forming chamber and a slice.

References Cited in the file of this patent UNITED STATES PATENTS 1,968,028 Clements July 31, 1934 2,134,408 Kellett Oct. 25, 1938 FOREIGN PATENTS 519,496 Germany Feb. 28, 1931 535,589 Germany Oct. 14, 1931 537,059 Germany Oct. 28, 1931

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