US3325351A - Water-extracting device in felt and press section for paper machines - Google Patents

Description

June i3, 196? L "1?". @WE'GN. J5; WATEREXTRACTING DEVICE IN FELT AND PRESS Filed June 19 1964 SECTION FOR PAPER MACHINES 3 Sheets-Sheet l 2 INVENTOR o SAMUEL T. 0RTON,JR.

ATTORNEYS q m, m mmmm, EJ255353 CE IN FELT AND PRESS PAPER mmmmas 3 Sheets-Sheet 2 W R Tum? :m 5T I AT .MS

WMWJEEW. T. OWTQW LEW.

June l Filed June 19, 1964 3 J r M d & .e

F P m n; L m. 0 in Eu P F June 13, 1967 s. T. QRTQN. JR 3,325,351 WATER-EXTRACTING DEVICE IN FELT AND PRESS SECTION FOR PAPER MACHINES Filed June 19, 1964 3 Sheets-Sheet 53 FIGS INVENTOR. SAMUEL T. ORTON, JR. BY

ATTORNEYS United States Patent 3,325,351 WATER-EXTRACTING DEVICE IN FELT AND PRESS SECTION FOR PAPER MACHINES Samuel T. Orton, Jr., Lunenberg, Mass, assiguor to Jean-Pierre Maupas, Rouen, France Filed June 19, 1964, Ser. No. 376,515 6 Claims. (Cl. 162-358) This invention relates to an improved device for extracting water from moving porous webs in paper machines, and more particularly to a device which combines the functions of press rolls with those of a roller suction box, in a single roll array, to remove water more eificiently, more uniformly, and with a minimum of equipment.

It has previously been proposed to combine suction with a pressing action by nipping the web between a single press roll and the periphery of a perforated roll having an internal suction system. This has not been wholly satisfactory for several reasons. A substantial increase in diameter is necessary to impart sufiicient stififness to a perforated roll to withstand the heavy load of a press roll applied against its periphery. The initial and maintenance costs of such large perforated rolls are very high. Furthermore, the larger diameter of the perforated roll results in an increased nip length in the direction of web travel, and this correspondingly reduces the pressure applied to the web, for a given loading on the press roll. The design factors of stiffness and nip pressure thus confiict with one another. A third disadvantage is the differential de-watering which is inherent in a perforated roll, since the spaces between holes apply no vacuum; the Water in the areas of the web between holes is not removed, and rewets the dried areas later, so that a relatively low percentage of contained moisture can be removed. An increase in the vacuum is not generally satis factory, as it may permanently mar the treated paper or other material in areas which overlie the holes in the roll.

It is known that a roller suction device which includes spaced-apart plain rolls, referred to in the trade as upper rolls, and forming gaps between them for applying suction to an overlying span of a tnaveling felt or web, affords an efficient and uniform drying action, According to the present invention, advantage is taken of the desirable water-extracting characteristics of such a roller suction unit, and this is accompanied by a wringing action performed in the same roll array. The array is such that the wrung-out water is drained directly into the suction gap to minimize the tendency to re-wet the web. In combination with a pair of spaced first or upper rolls at fording a suction gap, I provide a press roll of relatively large diameter and transverse stiffness, which engages each of the upper rolls in tangential rolling contact to seal the suction gap opposite the treated web; and a further press roll, whose rotational axis is arranged in a common plane with the axes of the first press roll and one of the upper rolls. The further press roll nips the web against the one upper roll; and being aligned in this manner, the two press rolls are enabled to apply a very substantial nip pressure against the web by acting diametrically oppositely on the upper r-oll between them. Consequently, the upper rolls need not have great transverse stiifness in themselves. On the contrary, they have a relatively small diameter in order to reduce the length of the nip to a minimum, so that the load which must be applied by the press rolls to obtain a given pressure per square inch on the web is correspondingly minimized. The upper press roll may be rubber-covered if desired, without greatly increasing the nip length, which is principally affected by the relatively small diameter of the nipped upper roll.

3,325,351 Patented June 13, 1967 The invention may be embodied in various forms; in particular, more than one roller suction unit may be incorporated in the same device, for applying suction to the felt or web both as it enters and as it leaves the nip of the rolls. This requires only one additional upper roll; two of the first or upper rolls are spaced symmetrically on opposite sides of an intermediate upper roll, which is nipped between the two press rolls.

In another form, two opposed units are provided for drying webs which pass through their common nip in overlapping relation, as when it is desired to use top and bottom felts on the same press for treating both surfaces of a sheet of paper. In this case, identical units, each comprising a pair of first or upper rolls and one press roll, are arranged in confronting relation to nip the sandwiched felts between one of the upper rolls of each unit. The axes of each of the press rolls are aligned in a common plane with the axes of the nipping opposed upper rolls, so that the same result is secured as in other forms.

The combination of suction and pressing action which the improved device affords is particularly effective in that the nip takes place immediately at one end of the span subjected to suction, and the water squeezed out by the nip is drawn directly into the suction gap so that rewetting is avoided. The nip length is determined b the diameter of the upper rolls, while the rigidity of the unit against deflection by the nip pressure is determined by the stiffness of the larger press rolls.

While the specification concludes with claims particularly pointing out the subject matter which I regard as my invention, it is believed that a clearer understanding may be gained from the following detailed description of preferred embodiments thereof, referring to the accompanying drawings, in which:

FIG. 1 is a schematic view showing the operative relationship of the roll array in a first form of the improved water-extracting device;

FIG. 2 is a view in elevation the device of FIG. 1;

FIG. 3 is a schematic view of a further embodiment;

FIG. 4 is a schematic view showing a roll array of still another form of the invention; and

FIG. 5 is a schematic view showing the arrangement of another embodiment.

In FIGS. 1 and 2, a first embodiment of the waterextracting device is shown in a typical installation for drying a sheet of paper which passes. through the roll array upon a continuous felt. The paper is guided into overlapping relationship with the felt by a suitable guide roll 10, and the felt is guided to and from the roll array by guide rolls 12 and 14.

The device incorporates a roller suction unit substantially as described in US. Patent No. 3,122,471, entitled Roller Faced Suction Box issued February 25, 1964 to lean-Pierre Maupas, the assignee of this application. This unit includes a pair of first or upper rollers 16 and 18 which have plain surfaces and are spaced apart to provide a gap or vacuum chamber 22 between them. This gap is closed at each end of the rolls by means of a cheek box 24, having upper and lower walls and a vertical end Wall to form manifolds 25 at the ends of the upper rollers, communicating with the gap 22. In one of the cheeks, an opening 26 (FIG. 1) is formed for communication with a vacuum pump (not shown) to establish suction within the gap, thereby to draw water from the felt, and thus indirectly from the paper. The ends of the upper rollers are formed with end portions 28 of reduced diameter for passage of sealing belts 30 about both upper rolls, to seal the vacuum gap by sliding engagement with peripheral recesses 32 formed in the cheeks. An axle 34 of each upper roll passes through suitable openings 36 formed in and partially in section of showing the roll array 3 the vertical walls of the cheeks, being sealed by rubber washers 38 or the like.

The shafts 34 pass freely through openings in frame I members 40 which form a part of the framework of the machine, and are journalled in bearings 42. The bearings and the cheek boxes are aligned and secured by threaded studs 44 and nuts 46. The belts 30 travel about the upper rolls at the same lineal velocity as the felt resting thereon, and serve to prevent premature wear of these edges as well as to seal the ends of the suction gap 24. The device thus far described accords substantially with the aforementioned patent of Jean-Pierre Maupas, and in itself forms no part of the present invention.

This suction unit is combined with a plain press roll 48 of a larger diameter and greater transverse stiffness than the upper rolls 16 and 18. This press roll engages each of the upper rolls tangentially in rolling fluid-tight contact, to close the suction space from below. A further plain press roll 50 which is similar to the roll 48, nips the moving felt and paper against the upper roll 16. The axles 54 and 60 of the press rolls are mounted in bearings 56 and 64 respectively, which are movably supported in pivotal arms 62 for application of a mutually-applied press load by any conventional means.

The nip of the rolls 16 and 50 wrings water from the web immediately at one end of the span passing over the suction space. The water so squeezed passes directly into the suction space Without having an opportunity to redistribute itself and thereby re-wet other portions of the web.

In order to afford sufficient effective rigidity to the small and relatively flexible upper roll to sustain a high press loading, the press rolls 48 and 50 have their rotational axes aligned in a common plane with that of the upper roll 16, thereby imparting their own greater rigidity. At the same time, the small diameter of the upper roll minimizes the length of the nip, which is therefore controlled la-r-gely by this diameter rather than by that of the press rolls. The nip pressure applied to the web for a given press roll load is maximized, because of the small area of contact. If desired, the surface of the roll 50 may be rubber-covered, which will tend to increase the area of the nip somewhat, but a commensurate reduction is nevertheless secured.

A variety of alternative arrangements are included within the scope of the invention in its broader aspects, and two of these are shown by way of example in FIGS. 3 and 4, in which parts similar to those of the previously described embodiments are similarly numbered. In FIG. 3, a second roller suction device is formed by the addition of a third upper roll 19, which cooperates with the upper roll 16, now in an intermediate position, to form a second suction unit for removing water from the felt as it leaves the nip of the rolls. The belt 30 in this case passes around the three upper rolls jointly. It will also be understood that .a single suction unit may be applied to the web on the outgoing side from the nip in applications where this is desirable, simply by omitting the leading upper roll 18 and its suction apparatus.

In FIG. 4, two suction devices are arranged in opposition for treatment of both surfaces of the paper by felts, as is particularly desirable in manufacturing papers of high surface quality. The nip in this case occurs between two upper rolls 16, one of which takes the former position of the roll 50; and whose axes are aligned once again with the axes of the press rolls 48 and 50, which thereby impart their transverse rigidity to both of the nipping upper rolls to permit an adequate press load to be applied.

The arrangement of another embodiment is shown in FIG. 5, which adds to the roll array of FIGS. 1 and 2 a third press roll 70 similar to the press roll 50, which nips the web against the upper roll 18 so that each end of the span passing over the suction space is squeezed. Again, the rotational axis of the third press roll 70 is aligned in a common plane with those of the press roll 48 and the upper roll 18, so as to impart stiffness to this upper roll as well. The spacing between the upper rolls should of course be sufficient to accommodate the press roll 50 and the third press roll without interference.

While I have illustrated and described preferred embodiments of my improved water-extraction device, vari ous changes and modifications will occur to those skilled in the art without departing from the true spirit and scope of the invention, which I therefore intend to define in the appended claims without limitation to the details of the illustrated embodiments.

I claim:

1. A water-extracting device for paper machines, comprising, in combination: a group of rotatably-mounted parallel cylindrical rolls having plain surfaces, and including at least two first rolls arranged for serial engagement by a traveling felt and spaced apart to form a suction gap for passage of a span of the traveling felt thereover; a press roll engaging each of said first rolls opposite to said span under pressure in tangential rolling fluid-tight contact; means cooperating with said rolls to seal said gap against fluid entrance other than through said span of the felt passing over said gap; means for establishing a vacuum within said gap to draw fluid thereto from said felt; and a further roll arranged to nip an end of said span under pressure against one of said first rolls, and having a rotational axis lying in a common plane defined by the rotational axes of said one first roll and said press roll; whereby said further roll and said press roll apply pressure in diametrically-opposite directions through said one first roll to the nipped end of said span, and water extracted from the nip by said further roll and said one first roll drains directly into said gap uniformly over the full width of said felt.

2. A water-extracting device as recited in claim 1, in which said one first roll is of substantially smaller diameter and transverse stiffness than said further roll and said press roll; whereby the differential in diameters effects a nip-length in the direction of travel of the felt determined by the diameter of said one further roll, and an effective rigidity against deflection by nip pressure determined by the stiffness of said further roll and said press roll.

3. A water-extracting device for paper machines, comprising, in combination:

a group of rotatably-mounted parallel cylindrical rolls having plain surfaces, and including; two pairs of first rolls each pair being arranged for serial engagement by a different one of two traveling felts, the rolls of each said pair being spaced apart from one another so that said pairs form two suction gaps each for passage of a span of one of the traveling felts thereover, two of said first rolls, comprising one roll of each of said pairs, being arranged to nip said two felts between them in overlapping relationship; and a pair of press rolls each engaging a different pair of said first rolls, opposite to the suction gap formed thereby, in tangential rolling fluid-tight contact, said press rolls having their rotational axes lying in a common plane defined by the rotational axes of said two felt-nipping first rolls, and being constructed and arranged to apply pressure in diametrically-opposite directions through said two felt-nipping first rolls to the portions of said spans nipped therebetween;

means cooperating with said rolls to seal said suction gaps against fluid entrance other than through the spans of the two felts passing over said gaps; and means for establishing a vacuum within each of said gaps to draw fluid thereto from said felts.

4. A water-extracting device as recited in claim 3, in

which said two felt-nipping first rolls are each of substantially smaller diameter and transverse stiffness than said press rolls; whereby the differential in diameter effects a nip length in the direction of travel of said felts which is determined by the diameters of said two felt-nipping first rolls and an eifective rigidity against deflection by nip pressure which is determined by the stiiTness of said press rolls.

5. A water-extracting device as recited in claim 1, together with another roll arranged to nip the opposite end of said span under pressure against the other of said first rolls, and having a rotational axis lying in a common plane defined by the rotational axes of said other first roll and said press roll.

6. A water-extracting device for paper machine-s, comprising, in combination: a group of rotatably-mounted parallel cylindrical rolls having plain surfaces, and including at least three first rolls arranged for serial engagement by a traveling felt and spaced apart to form suction gaps therebetween for passage of spans of the traveling felt thereover; a pres-s roll engaging each of said first rolls opposite to said spans under pressure in tangential rolling fluid-tight contact; means cooperating with said rolls to seal said gaps against fluid entrance other than through said spans of said felt passing over said gaps; means for establishing vacuums within said gaps to draw fluid thereto from said felt; and a further roll arranged to nip said felt under pressure against an intermediate one of said first rolls, and having a rotational axis lying in a com mon plane defined by the rotational axes of said intermediate first roll and said press roll; whereby said press roll and said further roll apply pressure in diametricallyopposite directions through said intermediate first roll to the nipped portion of said span, and Water extracted from the nipped portion by said further roll and said intermediate first roll drains directly into said gaps uniformly over the full width of said felt.

References Cited UNITED STATES PATENTS 1,183,273 5/1916 Binns 162-366 1,950,853 3/1934 Lamont 162*373 X 2,780,968 2/1957 Heys l62-358 S. LEON BASHORE, Primary Examiner.

Claims (1)

1. A WATER-EXTRACTING DEVICE FOR PAPER MACHINES, COMPRISING, IN COMBINATION: A GROUP OF ROTATABLY-MOUNTED PARALLEL CYLINDRICAL ROLLS HAVING PLAIN SURFACES, AND INCLUDING AT LEAST TWO FIRST ROOLS ARRANGED FRO SERIAL ENGAGEMENT BY A TRAVELING FELT AND SPACED APART TO FORM A SUCTION GAP FOR PASSAGE OF A SPAN OF THE TRAVELING FELT THEREOVER; A PRESS ROLL ENGAGING EACH OF SAID FIRST ROLLS OPPOSITE TO SAID SPAN UNDER PRESSURE IN TANGETIAL ROLLING FLUID-TIGHT CONTACT; MEANS COOPERATING WITH SAID ROOLS TO SEAL SAID GAP AGAINST FLUID ENTRANCE OTHER THAN THROUGH SAID SPAN OF THE FELT PASSING OVER SAID GAP; MEANS FOR ESTABLISHING A VACUUM WITHIN SAID GAP TO DRAW FLUID THERETO FROM SAID FELT; AND A FURTHER ROLL ARRANGED TO NIP AN END OF SAID SPAN UNDER PRESSURE AGAINST ONE OF SAID FIRST ROLLS, AND HAVING A ROTATIONAL AXIS LAYING IN A COMMON PLANE DEFINED BY THE ROTATIONAL AXES OF SAID ONE FIRST ROLL AND SAID PRESS ROLL; WHEREBY SAID FURTHER ROLL AND SAID PRESS ROLL APPLY PRESSURE IN DIAMETRICALLY-OPPOSITTE DIRECTIONS THROUGH SAID ONE FIRST ROLL TO THE NIPPED END OF SAID SPAN, AND WATER EXTRACTED FROM THE NIP BY SAID FURTHER ROLL AND SAID ONE FIRST ROLL DRAINS DIRECTLY INTO SAID GAP UNIFORMLY OVER THE FULL WIDTH OF SAID FELT.

Images