US3537954A - Papermaking machine - Google Patents

Description

Nov. 3, 1970 E. J. JusTus PAPERMAKING MACHINE 4 Sheets-Sheet 1 Filed May 8, 1967 INVENTOR. EOGrAK J J/sTuS ,131 E. J. JUSTUS 3,537,954

PAPERMAKING MACHINE Filed May B, 1967 4: Sheets-Sheet 2 FIGURE 2 INVENTOR.

EDGAR IT Jus-rus Nov. 3, 1970- E.J.JUSTUS 7 3,537,954

PAPERMAKING MACHINE Filed Ma s, 1967 4 Sheets-Sheet a HGU E' A FIGURE 6.

I NVENTOR.

EDGflR I J us-rus Nov. 3, 1970 E. J. JUSTUS I 3,537,954

PAPERMAKING MACHINE Filed May 8, 1967 4 Sheets-Sheet 4 HGURE 4 INVENTOR. mm \7 $5M:

3,537,954 PAPERMAKING MACHINE Edgar J. Justus, Beloit, Wis., assignor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed May 8, 1967, Ser. No. 636,749 Int. Cl. B31f 1/12 US. Cl. 162-305 4 Claims ABSTRACT OF THE DISCLOSURE Apparatus for producing creped paper which utilizes a conventional headbox and Fourdrinier arrangement for forming and partially drying a web of paper. The web is removed from the Fourdrinier by means of a conventional pick-up felt and deposited on the surface of a heated drying cylinder. Immediately thereafter, a relatively coarse plastic fabric or other patterned device is urged against the web to impart a predisposed creping pattern to the web without disturbing or reducing the initial contact area of the web with the drying cylinder. After the web has reached the desired degree of dryness it is removed from the surface of the drying cylinder by means of a creping doctor urged against the cylinder surface. The web will follow the creping pattern previously imposed on it.

BACKGROUND OF THE INVENTION The creping of paper has been practiced on a commerical scale for many years during which time the methods employed have undergone little change. The most commonly used method involves doctoring or scraping a web of paper from a heated cylinder to which the web has been caused to adhere by the application of pressure. When the web approaches the doctor blade, it is compressed while in contact with the cylinder and buckles into a folded or wrinkled structure.

A major disadvantage of the above procedure resides in the pre-pressing operations performed on the web prior to its removal from the drying surface by the doctor blade. While these pressing operations are important from a water removal and web strength point of view, they do tend to reduce the desired bulk and softness of the end product.

It has been proposed to solve this problem by imparting a knuckle pattern to the web prior to or simultaneously with the disposition with the web on the heated drying surface. A major disadvantage of this approach lies in a drastic reduction in effective contact area of the knuckled web with the drying surface. Such reduction in contact area results in a substantial reduction of drying capacity and invariably requires additional web drying equipment.

SUMMARY OF THE INVENTION By utilizing the principles of the present invention, I am able to impart a predisposed creping pattern to the web while maintaining maximum contact of the web with the drying surface.

In one embodiment of the invention, the above is accomplished by forming a web of paper in a conventional manner on a Fourdrinier. The thus formed and partially dried web is removed from the Fourdrinier by means of a relatively soft and resilient pick-up felt which transports the web of paper to a relatively large diameter heated drying cylinder. Due to the resilient nature of the pick-up felt, the paper web is brought into intimate contact with the surface of the drying cylinder.

Immediately thereafter the web, while on the surface of the drying surface, is pressed with a relatively coarse and hard surface which forms a multiplicity of transverse United States Patent O 3,537,954 Patented Nov. 3, 1970 ridges in the web. These ridges will form the pattern for the subsequent creping operation.

In another embodiment of my invention, a web is formed in a conventional manner on the Fourdrinier whereafter the web is subjected to a pressing action while it is sandwiched between a relatively soft and resilient paper making felt and a relatively coarse and hard fabric. The fabric will impart a predisposed creping pattern to the web which is thereafter deposited on the drying surface of a relatively large diameter drying cylinder by means of a relatively soft papermaking felt whereby intimate contact with the drying surface is obtained while the predisposed creping pattern is not disturbed.

In a further embodiment of my invention, a web of paper is formed between two relatively coarse and hard web-forming fabrics one of which retains the web on its surface and transports it to a drying cylinder. At the point of disposition of the web on the cylinder by the fabric, the fabric is backed by a resilient and a soft paper making felt thereby insuring intimate contact of the web with the surface of the drying cylinder. The creping pattern is imparted to the web by means of the fabric.

In a still further embodiment of my invention a web is formed between two relatively coarse and hard forming fabrics in a conventional manner after which the web is transported to and deposited on the surface of a large diameter drying cylinder by means of a carrying fabric which is basically resilient and soft but which has an outer periphery containing a multiplicity of regularly spaced hard twisted yarns or monofilaments arranged perpendicularly to the direction of travel. The hard twisted yarns or monofilaments will impart the desired transverse ridges to the web for predisposing a creping pattern on the web while the basic soft and resilient fabric will insure intimate contact of the web with the drying surface.

It is therefore, an object of my invention to accomplish the embodiments set forth above.

Other objects of my invention will become apparent to those skilled in the art from the following detailed descriptions of the annexed sheets of drawings which, by the way of preferred examples only, illustrate apparatus of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic elevational View of a papermaking machine according to the present invention.

FIG. 2 is a diagrammatic elevational view of a papermaking machine showing another embodiment of the present invention.

FIG. 3 is a diagrammatic elevational view of a papermaking machine showing a further embodiment of the present invention.

FIG. 3a is an enlarged fragmentary elevational view of part of the invention as shown in FIG. 3.

FIG. 4 is a diagrammatic elevational view of a papermaking machine according to a still further embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the FIG. 1 of the drawings a headbox 1 supplies papermaking stock to the upper run of a Fourdrinier wire 2 to form a web W. The Fourdrinier wire is trained around a breast roll 3, a couch roll 4, a wire turning roll 5 and a wire guide or tension roll 6. Suction boxes 7 may be provided on the underside of the 'Fourdrinier wire for additional water removal. An upper wire run 8 is provided for in a conventional manner and a suction box 9 is disposed within the upper Wire loop for removal of water from the Web W in an upward direction. Between the couch roll 4 and the wire turning roll 5, the web is removed from the inclined wire span by means of a pickup roll or other suitable means located within the loop of a pickup felt 11. The pickup felt 11 transfers the web to a pressure roll 12 which is in nip defining relationship with a large diameter heated drying cylinder 13. The felt wrapped pressure roll 12 is urged against the drying cylinder 13 at a nip N1 with a suflicient amount of pressure to cause the web to be firmly adhered to the surface of the drying cylinder.

Immediately following the application of the web to the surface of the drying cylinder the web is brought into pressure contact with a relatively coarse fabric 14. The fabric 14 is wrapped around a pressure roll 15 which is in nip defining relationship with the surface of the drying cylinder 13 so as to form a second nip 'N2.

The fabric 14 is preferably in the form of a woven synthetic monofilament material having approximately 25 to 80 meshes per inch. The diameters of the filaments extending in a cross machine direction may be anywhere within the range of .005 to .020 inch.

The fabric 14 is urged against the web on the drying cylinder 13 with sufficient pressure to impart to the web a plurality of ridges extending in a cross machine direction. It is important to note that these ridges are imparted to that side of the web which is not in contact with the drying surface so that the intimate contact obtained between the web and the drying surface at the nip N-1 is not disturbed. In order to avoid the necessity of an increase in web drying capacity it is therefore important to insure that the web is uniformly and firmly urged against the drying surface 13 prior to imparting the creping pattern to the web. After the web has been dried to the desired degree by means of the drying cylinder 13 the web is removed from the surface of the drying cylinder by means of a doctor blade D. When the web approaches the doctor blade it is compressed while in contact with the drying cylinder. The compressive force exerted on the web W by the doctor blade will cause the web to wrinkle and buckle in accordance with the pattern previously imparted to the web.

This procedure will accomplish the objects of my invention in that it will result in a web having improved bulk, softness and absorbency while maintaining web strength and without the necessity of additional web drying equipment.

For example, the need for additional drying equipment could not be eliminated if the felt loop 11 was bypassed thereby removing the web from the Fourdrinier wire by means of the fabric 14 and subsequently depositing the web on the surface of the drying cylinder with the fabric 14. Such a procedure would result in localized pressure areas under the cross machine extending filaments of the fabric 14 with very little contact pressure between the filaments thus resulting in nonuniformed disposition of the web on the drying surface with a subsequent reduction in drying capacity.

In the embodiment shown in FIG. 2 the web of paper is formed between an upper relatively coarse fabric 16 and a lower forming wire 17 in substantially the same manner as described in connection with FIG. 1.

The fabric 16 is of the same design as described in connection with FIG. 1. The upper fabric 16 travels around a pickup roll 18 which carries the web W into a nip N-3 defined by an upper roll 19 and a lower roll 20. The lower roll 20 is located within the loop of a relatively soft and resilient paper making felt 21. At the nip N-3 a pre-disposed creping pattern is imparted to the web which, at the nip, is sandwiched between the fabric 16 and the felt 21. The web is then carried to a nip N-4 by means of the felt 21. The purpose of the nip N-4 is to transfer the web to a felt loop 22 which transports the web to a pressure roll 23. The creping pattern imparted to the web at the nip N-3 will be on the upper side of the web between the nips N-3 and N-4. The smooth side of the web will face the felt between the nips N-3 and N-4. Immediately following the nip N4 the web is transferred to the soft and resilient papermaking felt 22 after which the patterned side of the web will face the felt 22. At the nip N-S defined between the pressure roll 23 and the drying cylinder 24, the smooth side of the web W will be firmly pressed against the drying cylinder 24 while the patterned side will face away from the surface of the drying cylinder. After the web has been dried to the desired degree it is removed from the drying cylinder 24 in the same manner as described in connection with FIG. 1.

In the embodiment shown in FIG. 3 the web W is formed between an upper forming fabric 25 and a lower Fourdrinier wire 26 in substantially the same manner as shown and described with respect to FIGS. 1 and 2. The web W is removed from the lower forming wire 26 by means of a pickup roll 27 located within the loop of the upper forming fabric 25. After the web is removed from the bottom Fourdrinier wire 26 it is conveyed to a large diameter drying cylinder 28 by means of the upper fabric 25. Located within the loop of the upper fabric 25 and defining a nip N-6 with the drying cylinder 28 is a pressure roll 29 which urges the fabric 25 with the web W against the surface of the drying cylinder. The pressure roll 29 is partially wrapped by a soft and resilient felt 30. The felt 30 may be in the form of a jacket completely surrounding the periphery of the roll 29 or it may be in the form of a loop as shown.

As shown in FIG. 3a the felt 30 will tend to push through theinterstices of the relatively coarse fabric 25 thereby substantially increasing the contact area between the web W and the surface of the drying cylinder 28. In this embodiment of the invention a predisposed creping pattern is imparted to the web W simultaneously with the application of the web to the surface of the drying cylinder. The relatively coarse fabric 25 imparts the desired creping pattern to the web while the relatively soft and resilient felt 30 insures a maximum contact with the surface of the drying cylinder 28 by pushing through the interstices of the fabric 25.

FIG. 4 shows a further innovation based on the basic principles of the present invention. The web W is formed in a conventional manner between upper and lower forming members 31 and 32 and is then removed from the lower forming member by means of a pickup roll 33. The pickup roll 33 is located within the loop of a pickup felt 34 having certain characteristic which will be described in detail below. The felt 34 transports the web W to a pressure roller 35 defining a nip N-7 with the drying cylinder 36. By application of heat and pressure the web W is transferred to the surface of the drying cylinder 36.

The felt 34 is of a special design in that its outer surface is textured n such a manner that a predisposed creping pattern is imparted to the web W at the nip N-7 between the pressure roller 35 and the drying cylinder 36. The design of the felt 34 will be obvious to those skilled in the felt making art and its weaving pattern may for example include hard twisted yarns or monofilament fillers running in a cross machine direction along the outer surface of the felt. These hard yarns or fillers should be spaced depending on the desired creping pattern. The hard yarns will cause higher localized pressure areas at the nip N-7 so that the creping pattern thus imparted to the web will follow the higher pressure areas to which the web has been previously subjected. The soft and resilient felt material located between the harder yarns will urge the web into intimate contact with the surface of the drying cylinder.

I claim as my invention:

1. A papermaking machine comprising in combination:

a looped forming wire having a longitudinally extending forming run;

a headbox for delivering a jet of papermaking stock to an upstream end of said forming run forming a web of paper thereon;

a drying cylinder mounted in space relationship to said forming wire and adapted to rotate about a horizontal axis;

a looped pickup felt having substantially no impressions thereon between said forming wire and said drying cylinder;

a pickup roll within the loop of said felt for urging said felt against forming wire and removing the Web of said paper therefrom;

a pressure roll within the loop of said felt urging said felt in said web against said drying cylinder whereby said web is deposited upon said drying cylinder; and

impression forming means for imparting impressions to said web after said web has been formed on said wire but before said web is removed from said drying cylinder, said impression forming means including a looped impression fabric having a pressure roll within the loop of said fabric for urging said fabric against said web after said web has been deposited on said cylinder, said web being carried by said cylinder from the point 'where said felt leaves said Web to the point where said impression fabric contacts said Web.

2. The apparatus as set forth in claim 1 wherein said impression fabric comprising a woven monofilament material having approximately to meshes per inch.

3. The apparatus as set forth in claim 2 wherein the diameter of said monofilaments is within the range of from 0.005 to 0.0020 inch.

4. The apparatus of claim 1 which further includes a second felt loop within the loop of said looped pickup felt and passing between said felt and said pressure roll within the loop of said felt at said point where said web and felt are urged against said drying cylinder, said second felt loop having substantially no impression characteristics.

References Cited UNITED STATES PATENTS 1/1967 Sanford et al. 162206 X 7/1903 Farwell 162-362 X US. Cl. X.R. l62ll3, 362

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