US3355350A

US3355350A - Paper machine

Info

Publication number: US3355350A
Application number: US419446A
Authority: US
Inventors: George E Reynolds
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1964-12-18
Filing date: 1964-12-18
Publication date: 1967-11-28
Anticipated expiration: 1984-11-28

Description

2 1967 Q G. E. REYNOLDS 7 3,355,350

PAPER MACHINE- Filed Dec. 18, 1964 it/W340:

3,355,350 PAPER MACHINE George E. Reynolds, Appleton, Wis., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed Dec. 18, 1964, Ser. No. 419,446 2 Claims. (Cl. 162-358) ABSTRACT OF THE DISCLOSURE A paper making machine in which a suction pickup roll is arranged ahead of a press assembly having a vertical stack of rolls the top roll of which is a suction press roll, with guide rolls positioned to guide a web along a downward enclosure to the pickup and top roll and along an upward incline therefrom, and with a save-all over the pickup and suction press roll having wall structures defining a moisture collecting pocket between these rolls and the upwardly inclined outrunning web, with the pocket having a curved cover surface with one or more inlet openings for collecting moisture thrown from the adjacent roll and an outlet opening for draining the water level in the pocket below an imperforate portion of the curved surface between a leading edge of the pocket and the inlet opening.

This invention relates to a paper making machine and in particular to a portion of the machine where a newly formed paper web is picked up and guided through a press section. The press section of a paper making machine is a section that receives a wet web of paper stock from a web forming section, for example, a Fourdrinier wire, and repeatedly squeezes the web to drive out water until the paper stock web is in condition to be passed over internally heated drying rolls in a subsequent portion of the machine called a drying section.

In early paper machines, such as shown in a Millspaugh patent, US. 1,163,253, Dec. 7, 1915, the newly formed wet web of paper stock was passed without support from the forming section across a space called an open draw, to the press section where a felt web supports the wet paper web while water is squeezed out of the paper web. A later development, called a suction pickup, eliminated the open draw and permitted much greater speeds while also reducing the frequency of breaking the paper web. An early form of a suction pickup is shown in a Mill- .suction boxes were provided within each of these rolls.

A first endless press felt web is passed over the lower roll and asecond endless press felt web is passed over the middle roll. The lower suction roll urged the first felt web against the paper web on the Fourdrinier wire to pick up the paper web from the wire and guide it through the first nip. The middle suction roll urged the second felt web against the paper web in the first nip to pick up the paper web and guide the paper web through the second nip. A still later development placed the plain surface roll in the middle of the stack in order to press the wire marked side of the paper web against a plain surface roll as it passes through the first and second nips to eliminate the wire marks before they'become set and much more difficult to press out. Such arrangements also featured the addition of a separate suction pickup roll ahead of the stack of three rolls and within the loop of the first felt web to pick the paper web oil the wire and guide the paper web into the first nip. With this separate pickup United States Patent roll the suction boxes in the bottom and top rolls of the stack function solely to draw water pressed from the paper web and this arrangement eliminated the need to move parts of the stack assembly out of the way when changing wires on the Fourdrinier.

The foregoing described developments of the prior art brought the state of the art to a need for a special device called a save-all arranged on the web-outrunning side of suction paper web pickup rolls and suction press rolls. As an outrunning paper web leaves a roll it passes beyond the area on the roll effected by the suction boxes and water remaining in the perforations of the roll is thrown outwardly by centrifugal force back down on top of the felt and/ or paper web. To catch such thrown water before it can land back on the paper and/or felt web the prior art provides the Web a downwardly in lined outrun and a pan (called a save-all) is arranged with a leading edge of a lip between the suction roll and the upper outrunning web and at approximately the horizontal level that the upper web peels oflf the suction roll. A back wall of the save-all extends above the level of the leading edge to catch the thrown water and the back wall together With the lip defines a water collecting trough below the level at which the upper web peels off the suction roll. Because this teaching of the prior art calls for a collecting trough below the level at which the upper web peels ed a suction roll, the outrun must be downwardly away from the roll and the stack of press rolls is tilted to locate the middle roll farther from the Fourdrinier section than the bottom roll, and the top roll farther from the Fourdrinier section than the middle roll, and the result is that an already undesirably long machine is made even longer. Accordingly, it is an object of the present invention to provide a new and improved suction pickup and press arrangements that prevent water throw back on the web without requiring a downward outrun from the pickup roll and/or stack of press rolls and wtihout requiring the stack of rolls to be tilted in a direction that lengthens the machine.

Another object of the present invention is to provide a new and improved save-all assembly for particular advantageous use with the novel suction pickup and press arrangements according to the present invention.

According to a preferred embodiment of the present invention, a suction pickup roll, within the loop of a first felt web, is arranged to urge the first felt web against a newly formed paper web on the couch roll end of a Fourdrinier wire. A pair of suction press rolls with a plain surface roll between them are arranged in a vertical stack closely spaced from the web-outrunning side of the pickup roll. The first felt web is looped around the bottom suction press roll in the stack to guide the paper web through the nip between the bottom and middle rolls of the stack. A second felt web is looped around the top suction press roll and makes contact therewith on the side defining a nipvwith the middle stack roll. The paper web moving away from the pickup roll and the upper web moving away from the top suction roll follow a path that is horizontal or upwardly inclined. A save-all is mounted over the pickup roll and over the top press roll. Each save-all, on the web-outrunning side thereof, has a flat surface at least as wide as the roll and the fiat surface is horizontal or inclined tangentially upwardly in the direction away from the roll. A curved surface having a curvature approximately equal to the curvature of the roll, and at least as wide as the roll, is connected to the edge of the flat surface facing the roll, and the curved surface bends upwardly parallel to the cylindrical outer surface of the adjacent roll. The upwardly curved surface is imperforate from the edge of the flat surface to a predetermined level above the edge of the fiat surface to define a pocket between the upwardly moving surface of the roll and the outwardly moving web. Each side of the defined pocket is enclosed by a vertical wall. One or both of the side walls define an opening for draining the pocket away from the paper and felt webs. The curved surface defines one or more openings above the predetermined imperforate level to admit water impinging thereon to the pocket. Since water thrown from a suction roll will be thrown along aline tangent with the roll where the suction ends, and with considerable velocity, some of the thrown water will pass directly through the openings, some of the water will strike the imperforate portion of the curved surface and (because of its velocity) fiow up to and through the perforate portion and some water will strike the curved surface above the perforate portion and either run down to the perforate portion or up and over the upper edge of the curved surface and into a secondary collecting trough which may be provided behind reinforcing structure extending between the flat surface and the curved surface. Such a secondary trough may be drained through openings in end walls or the reinforcing structure may have openings for water to flow into the pocket and then to drain. The pocket is suction drained and the trough by gravity. With this arrangement water thrown by a suction roll with a web being peeled off the roll horizontally or upwardly, can be collected and drained away from the Web with substantially the same efficiency as in arrangements having downwardly extending outruns, and with a more compact and shorter machine.

Other objects and how they are attained will appear from the following more detailed description of the invention with reference to the drawings in which:

FIG. 1 is a diagrammatical view of a paper machine press section with a suction pickup ahead of the press section, according to the present invention; A

FIG. 2 is a fragmentary detail view on the web outrun- 'ning side of a suction roll, according to one embodiment of the present invention; and

FIG. 3 is a fragmentary detail view on the web outrunning side of a suction roll, according to another embodiment of the present invention. '7

Referring to FIG. 1, a paper making machine is shown comprising a looped forming wire upon which a paper web 11 is formed and the forming wire 10 travels over a couch roll 12 and then around a turning roll 13 to reverse the direction of the forming wire 10.

A looped pickup and press felt web 14 is provided and a suction pickup roll 15, having an internal suction box 1517, is arranged within the loop of the pickup felt web 14. The suction pickup roll 15 urges the pickup felt web 14 against the paper web 11 on the forming wire 10 between the couch roll 12 and the turning roll 13. The suction drawn through box 15a within roll 15 transfers the paper web 11 from the forming wire 10 to the underside of the felt web 14. A guide roll 16 is mounted above and ahead of the location of the transfer of the paper web 11 from wire 19 to felt Web 14. The guide roll 16 is within the loop of the pickup felt web 14 and cooperates with V the suction pickup roll 15 to define a forward outrun of felt web 14 from suction pickup roll 15 to provide a generally horizontal or upwardly forward reach 14a of the felt web 14. As shown, the reach 14a is sloped upwardly about 10 degrees from horizontal in the direction of travel.

Above the guide roll 16 a press, indicated generally by P, is suitably mounted. The press P comprises a pair of press rolls 17 and 18 defining a press nip N-1 therebetween. Suction press roll 17 is above and behind the guide roll 16; and bare press roll 18 is directly above suction press roll 17. A second reach 14b of the felt web 14 extends from guide roll 16 to the press nip N-1. The

first reach 14a and the second reach 14b define an angle of approximately 80 degrees, whereby the felt 14 is actually reversed in direction as it guides the paper web 11 from the forming wire 10 to the first press nip N-l.

The first press nip N-l is defined by a suction roll 1.7

4 V having a suction box 17a at the oncoming side of the nip N1 and a plain roll 18 outside of the felt loop 14. The suction roll 17 is within the felt loop and is below the nip N-l, so as to permit free flow of water from the press nip N1 downwardly and generally in the direction of the suction area 17a. The described arrangement provides complete reversal of the travel of the paper web 11 on the felt web 14 so that the felt web 14 which initially engages the top of the paper web 11 on the forming wire 10 and supports the paper web 11 from above during the initial reach 14a can function to support the paper web 11 from below at the first press nip N-l.

At the first press nip N-l the paper web 11 is still quite wet and a substantial amount of water is removed therefrom, thus resulting in adherence of the wet web 11 to the plain-surfaced roll 18 at the offruning side of. he nip N-l. The suction area 17a preferably does not extend beyond the nip N-1 so that it will not serve to cause the web 11 to tend to remain on the felt 14 at the offrun-ning side of the nip N-l. This lack of suction plus the tendency of a partially dried web to adhere to the plain surface of the roll 18 will permit the web 11 to remain on the surface of the roll 18 and travel therewith.

The paper web 11 transfers to the plain surface of the roll 18 at the first press nip N-l and continues on the surface of the roll 18 through a second press nip N-2 defined with another roll 20 directly above the plain roll 18 and the web 11 is ultimately removed from the plainsurfaced roll 18 by a doctor 19 as indicated in the drawing. The nip N-2 is upwardly inclined about 10 degrees from the horizontal as shown in the drawing, and the suction box 20a of the roll 20 is arranged so as to straddle the nip area of the second nip N-2. In this arrangement the suction area 204 extends an appreciable distance on the oncoming and on the offrunning side of the nip N-2 and the suction ,area 20a of the roll 20 is completely covered by a press felt web 21 so that contact between the press felt 21 and the paper web 11 is made only at the nip area. The amount of felt covered suction area 20a at both the oncoming and the oifrunning sides of the nip N-2 is at least equal to the area and preferably is two or three times greater than the nip area. In other words, the nip area or actual pressure area in the nip N-'2 where the web is actually pressed against the felt 21 may be a given length of perhaps one inch (peripherally), whereas the suction area covered by the felt 21 will extend on the oncoming side two, three or more inches from the actual nip area, and the suction area on the oncoming side is completely covered by the felt 21 at all times. In like manner, the suction area will extend two or three inches beyond the actual nip area at the olfrunning side and will be entirely covered with the felt 21. This permits drying of the felt 21 and opening of the pores thereof at both sides of the nip so as to greatly improve the ability of the suction area 204 to dewater the web and remove water accumulating at the nip N2 Also, the separation of the web 11 adhering to the plain surface roll 18 and the felt 21 immediately "at the otfrunning side of the nip N-2 serves to break a'vacuum which tends to develop between the paper web 11 and the felt web 21 and thus preventa tendency to draw water through the nip N-2.

It will also be noted that the felt 21 Passes under a guide roll 22 in an upwardly inclined plane (i'.e., about 10 degrees above horizontal).

A save-all 25 is mounted over suction pickup roll -15 J and another save-all 25a is mounted over suction press roll 20. Each save-all 2 5 and 25a has a housing 26 that envelops about 270 degrees of the space over each

poll

15, 20 for catching Water thrown from the surfaces of these rapidly turning rolls. The housing 26 defines a water collecting trough 27 on the web inrunning side of each of the

rolls

15, 2 0. The troughs 27 are each provided with a drain 28 for disposing of water collected in the troughs 27, The web outrunning side of the save-ails 26 will be described with reference to FIG. 2 and FIG. 3.

Referring to FIG. 2, each say-all 25, 25a has on the web outrunning side thereof, a housing 26 including a flat surface 30 shown inclined in the direction away from the roll and with a slope which as shown is about degrees from horizontal. A curved surface 31, having a curvature approximately equal to the curvature of

rolls

15, 20 and at least as wide as the rolls, is connected to the edge 32 of the flat surface 30 facing the roll, and the curved surface 31 bends upwardly parallel to the cylindrical outer surface of the adjacent roll. The upwardly curved surface 31 is imperforate from the edge 32 of the flat surface 30 to a predetermined level above the edge 32 of the flat surface 30 to define a pocket 33 between the upwardly moving surface of the adjacent suction roll and the outwardly moving web. Each side of the defined pocket 33 is enclosed by a vertical wall 34. One or both of the side walls 34 define an opening 35 for draining the pocket 33 away from the paper and felt webs. The curved surface 31 in FIG. 2 defines a horizontal slot 36 opening above the predetermined imperforate level to admit water impinging thereon to the pocket 33. Since water thrown from a suction roll will be thrown along a line tangent with the roll where the suction box ends, and with considerable velocity, some of the thrown water will pass directly through the slot 36, some of the water will strike the imperforate portion of the curved surface 31 and (because of its velocity) flow up to and through the slot 36 and some water will strike the curved surface 31a above the slot 36 and either run down to an inwardly curved upper lip 31b and then through slot 36 or up surface 31a and over an upper edge 36 of the curved surface 31a and into a secondary collecting trough 37 which may be provided behind reinforcing structure 38 extending between the flat surface 30 and the curved surface 31a. Such a secondary trough 37 may be drained through openings 39 in end walls 34 or the reinforcing structure 38 may have openings (not shown) for water to flow into the pocket 33 and then to drain through opening 35. The construction shown in FIG. 3 is the same as the showing of FIG. 2 except that a plurality of holes 40 are provided in curved surface 31 to admit water to the collecting trough 33.

With the arrangements that have been described, water thrown by a suction roll with a web being peeled off the roll horizontally or upwardly, can be collected and drained away from the web with substantially the same efficiency as in arrangements having downwardly extending web outruns, and with a more compact and shorter machine.

From the foregoing it will be understood that the present invention is possessed of unique advantages. However, such modifications and equivalents of the disclosed concepts such as readily occur to those skilled in the art are intended to be included within the scope of this invention and thus the scope of this invention is intended to be limited only by the scope of the claims such as are, or may hereafter be, appended hereto.

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

1. A save-all assembly for the web outrunning side of a suction roll for paper making machines, comprising: a housing structure having a top portion, a side wall portion depending from said top portion and a flat bottom surface connected to a lower part of said depending side wall portion, said bottom surface extending inwardly a predetermined distance from said side wall portion and terminating with an edge parallel to said side wall portion; a curved surface connected to said edge and bendin upwardly therefrom to define with said bottom surface a moisture collecting pocket, said curved surface having an imperforate portion from said edge to a predetermined level within said pocket above which said curved surface defines a moisture admitting inlet opening therethrough in communication with said pocket; and a pair of spaced vertical end walls enclosing the laterally spaced ends of said pocket, at least one of said end walls defining an outlet opening at least in part below said imperforate portion of said curved surface between said edge and said inlet opening to drain said pocket.

2. In a paper making machine having a suction pickup roll ahead of a press assembly having a vertical stack of rolls the top roll of which is a suction press roll, said pickup roll and said top roll each being covered by ,a save-all assembly, means for guiding a web beneath said pickup roll and later beneath said top roll, said guiding means including ,a pair of guide rolls, one positioned adjacent the web outrunning side of said pickup roll and the other adjacent the web outrunning side of said top roll and each at a level above the bottom of the adjacent of said rolls to guide a web from each of said rolls along a path inclined upwardly in the direction of web travel away from each of said rolls, and said save-all comprising a housing structure having a top portion, a side wall portion depending from said top portion and a flat bottom surface connected to a lower part of said depending side wall portion, said bottom surface extending inwardly a predetermined distance from said side wall portion and terminating with an edge parallel to said side wall portion; a curved surface connected to said edge and bend ing upwardly therefrom to define with said bottom surface a moisture collecting pocket, said curved surface having an imperforate portion from said edge to a predetermined level within said pocket above which said curved surface defines a moisture admitting inlet opening therethr ough in communication with said pocket; and a pair of spaced vertical end walls enclosing the laterally spaced ends of said pocket, at least one of said end walls defining an outlet opening .at least in part below said imperforate portion of said curved surface between said edge and said inlet opening to drain said pocket.

References Cited UNITED STATES PATENTS 3,098,788 7/1963 Hornbostel 162358 DONALL H. SYLVESTER, Primary Examiner.

A. C. HODGSON, Assistant Examiner.

Claims

1. A SAVE-ALL ASSEMBLY FOR THE WEB OUTRUNNING SIDE OF A SUCTION ROLL FOR PAPER MAKING MACHINES, COMPRISISNG: A HOUSING STRUCTURE HAVING A TOP PORTION, A SIDE WALL PORTION DEPENDING FROM SAID TOP PORTION AND A FLAT BOTTOM SURFACE CONNECTED TO A LOWER PART OF SAID DEPENDING SIDE WALL PORTION, SAID BOTTOM SURFACE EXTENDING INWARDLY A PREDETERMINED DISTANCE FROM SAID SIDE WALL PORTION AND TERMINATING WITH AN EDGE PARALLEL TO SAID SIDE WALL PORTION; A CURVED SURFACE CONNECTED TO SAID EDGE AND BENDING UPWARDLY THEREFROM TO DEFINE WITH SAID BOTTOM SURFACE A MOISTURE COLLECTING POCKET, SAID CURVED SURFACE