US3039496A - Papermaker's wet felt - Google Patents

Description

June 19, 1962 M HELLAND 3,039,496

PAPERMAKER'S WET FELT Filed March 6, 1958 j ATTORNEYS.

United States Patent O 3,039,496 PAPERMAKERS WET FELT Howard M. Helland, Newfane, N.Y., assignor to Lockport Felt Company, liuc., Newfane, NX. Filed Mar. 6, 1958, Ser. No. 719,586 7 Claims. (Cl. 139-383) This invention relates to improvements in papermakers wet felt constructions, such as are used in the manufacture of paper, paper board, pulp, and like products. For example, the invention relates to improvements in papermakers felts of the types disclosed in U.S. Patents 2,165,- 772; 2,271,295; and 2,423,828.

It is a primary object of the present invention to provide for the papermakers felt art, specifically an improved wet felt constructed of fibres such as the conventionally used grades of wool, cotton, and other natural and synthetic iibers; manipulated by means of a novel technique in this art so as to provide an improved papermakers wet felt of many advantages. The yarns employed may be produced by either the so-called woolen system or any of the so-called worsted systems.

A more specic object of the invention is to provide a felt as aforesaid which is of improved eciency as a drainage filter in its intended use.

Another object is to provide a felt construction as aforesaid which may be readily produced by presently standard ltype textile equipment, and at no increased cost.

Still another object is to provide a felt as aforesaid which presents a working surface of improved smoothness and pulp supporting and cushioning characteristics.

Still another object of the invention is to provide a felt as aforesaid which also is adapted to better resist the rigors of paper making operations, resulting in longer useful life of the felt and lower ultimate cost to the user.

Other objects and advantages of the invention will appear from the specification hereinafter.

It is well known in the papermakers wet felt art that it is usually the desideratum to provide a fabric structure which is basically strong and tension-resistant, while at the same time comprising an eflicient water-drainage or filter membrane in the form of a resilient mass comprising woven yarns in which the individual yarns appear to have lost their identities. For such purposes the wool and/or other fibres must be so entangled and commingled and blended 4as to present to the pulp being treated a uniformly smooth and level yet resilient surface. Numerous textile weaves have been heretofore devised with a View to accomplishing some or all of the above stated objects of the present invention, but such fabrics as have been heretofore devised and used in the papermakers felt art have failed to accomplish ythe above stated objects. The present invention provides the desired results through use f a novel combination of variously formed yarns, as illustrated by way of example in the accompanying drawings wherein:

FIG. 1 is a composite diagrammatical view illustrating fabrication of the filler plied yarn stock material of the woven structure of the present invention;

FIG. 2 is an elevational diagrammatic view (on enlarged scale) of the plied yarn formed by the process of FIG. l;

FIG, 3 is a diagrammatic fragmentary plan view of a woven fabric embodying filler yarns as illustrated by FIGS. l, 2 and warp yarns of conventional form, subsequent to initial weaving of the fabric;

FIGS. 4, 5 are fragmentary diagrammatic sectional views taken along lines IV-IV -and V-V of FIG. 3; and

FIG. 6 is a fragmentary sectional view diagrammatical- 1y illustrating the structure of the fabric upon completion of its manufacture and when tensioned incidental t0 its use as a papermakers felt.

As hereinabove stated, a primary object of the present "ice invention is to provide a novel woven felt structure wherein substantial components of the woven yarns have substantially lost their individual identities; and wherein the individual fibres of major yarn components of `the structure are entangled and interlocked `and blended to -an improved degree. Hence, the natural abilities of each fibre to do more work in the intended purpose of the felt, are given freer rein. To accomplish this purpose it is contemplated that as many as possible of the individual fibres, subsequent to the weaving operation, must be substantially free to move relative to one another `during the fabric fulling or milling operations. Thus, it follows that when the yarns are woven the individual fibres thereof must be under minimum constraint; and in accord with the present invention this desired effect is obtained by weaving the fabric of a large percentage of yarns in which the libres are substantially untwisted, compared to twisted fibre yarns as are conventionally embodied in such fabrics. More specifically, the invention contemplates that in order to give the iinished felt necessary belt-tension strength characteristics, the warp yarns of the fabric `are provided of relatively hard twisted yarn form, while the ller components of the fabric are formed of a novel plied yarn wherein the individual iibres are substantially untwisted about their own axes while being spirally wound about the neutral axis of the yarn, as will now be described in more detail.

The first step in preparation of the filler stock material for the fabric of the present invention is schematically illustrated at station A of FIG. 1 of the drawing herewith, wherein conventional type Lcard roping l@ comprising individual fibres 12 is given a conventional draft and minimum S twist into conventional singles yarn form as indicated at 14. Then, as a separate operation, and as illustrated at station B of FIG. l, a plurality of singles yarns such as the two yarns 1li-14 shown in FIG. l are entwined by means of a neutralizing Z twist. Hence, the resultant plied yarn designated 15 (FIGS. 1, 2) comprises intertwined singles yarn, the individual fibres of which are as near as possible untwisted.

Solely by way of one typical example, the card roping 10 may be initially drafted and S twisted at the rate of say 4.0 t.p.i, (twists per inch), according to the fibre lengths and other variables. The two singles yarns so produced may then be relatively entwined by means of a neutralizing Z twist in such manner as to provide a plied yarn of say 4.5 t.p.i. Experience indicates that approximately such a ratio of singles and plied yarn twists will result in production of a plied yarn as indicated at 15 in the drawing wherein the individual libres are only very slightly twisted (in one direction or the other) or are substantially untwisted about their own axes, while gently winding spirally about the neutral axis of the yarn. In the alternative, the card roping may be formed into singles yarn stock by means of a Z twist operation, and the singles yarns may thereupon be S twisted into plied yarn form, to provide the filler yarn stock 15 as explained hereinabove. In either case the plied yarn stock may be described as comprising two groups of untwisted libres gently rolling around one another. Due to the fact that the singles yarns 14-14 are relatively entwined the overall structure of the plied yarn 15 has adequate strength to withstand the subsequent weaving operation, in spite of `the fact that the individual libres are substantially untwisted.

As a separate preliminary to the fabric weaving operation the warp components of the fabric are prepared by any suitable standard yarn making operation whereby conventional type relatively hard twisted yarns 16 are provided for shuttle weaving (FIG. 3) with the yarns l5 hereinabove described. Thus, as shown in FIG. 4, the relatively soft fillers l5 are linked together by the relaspaanse tively hard twisted and tension-resistant warp yarns 16. This relatively loosely woven fabric is then submitted to the standard shrinking and fulling or milling operations. Thus, the fabric is shrunk such as to the form shown in FIG. and then is fulled into the form illustrated by FIG. 6 wherein the warp threads i6 are substantially straightened out to their conditions of maximum efficiency with respect to resistance to tension loads on thefelt. Whereas, FIG. 3 illustrates a felt fabric of the present invention to be of plain weave type, it will be understood that `the fabric may with equal facility and advantage be made up in any other weave pattern.

Whereas, the warp yarns 16, due to their relatively hard twisted natures, retain their needed optimum tension resistance characteristics, the relatively soft filler yarns easily deform and bulk out and respond in improved manner to the fulling treatment because the individual fibres thereof are of improved mobility. Hence, in the resulting felt fabrication the fibres 12 of the initial ropings i@ more fully surround the warp yarns if and provide a mat of superior surface smoothness and cushioning characteristics. Since the surfaces of the felt comprise bulks of fibres giving superior elasticity or cushion characteristics, the tension carrying yarns 16 of the structure are thereby insulated and protected against abrasion damage to an improved degree. At the same time the relatively open fibres of the filler yarns operate with maximum efficiency in accord with the phenomenon of capillarity and in response -to the pumping action within the felt when passing through compression rolls, to improve its water removing abilities. Thus, each fibre of the fabrication is d-isposed to act more efficiently in its assigned task.

By virtue of the present invention a wet felt of more open or coarser structure may be made to meet specifications heretofore met only by felts of finer construction. Hence, these new felts will be of superior drainage characteristics. Yet, by reason of the more efficient bulking of the fibres in the felt of the invention, it is also of superior surface or finish characteristics. Hence, especially in the field of the finer felts, substantial reductions in the'number of picks required to produce a desired finish to the paper product is practicable; thereby reducing the weaving expense and the cost of the felt to the user.

Thus, the finished fabric of the present invention presents a surface of improved smoothness and levelness and cushioning characteristics while the overall fabric is of optimum structural strength and of improved resistance to belt life shortening hazards, such as abrasion and the like. Also, the fabric may be of less weight to meet comparable performance specifications; yet costs no more to manufacture than do the prior art type wet felts hereinabove referred to.

It will of course be appreciated that the invention is not limited to the precise constructions illustrated herein and described hereinabove, and that the latter may be modified without departing from the spirit of the invention or the scope of the appended claims I claim:

1. A new article of manufacture comprising a papermakers wet felt for supporting and draining paper making material, said felt comprising a belt-like woven structure having relatively hard twisted warp yarns nmning lengthwise thereof and plied filler yarns running transversely thereof, said filler yarns having their individual fibres spirally wound but substantially untwisted about their own axes, said filler yarnseach comprising a pair of singles yarns each comprising card roping twisted into conventional S twisted yarn form and Z twisted in opposite direction together into plied yarn form, said woven fabric being fulled.

2. A new article of manufacture comprising a papermakers wet felt for supporting and draining paper making material, said felt comprising a belt-like woven structure having relativeiy hard twisted warp yarns running lengthwise thereof and plied filler yarns running transversely thereof, said filler yarns having their individual fibres substantially untwisted about their own axes, said filler yarns each comprising a pair of singles yarns twisted together in plied yarn form, each of said singles yarns comprising card roping twisted in opposite direction into singles yarn form, said woven fabric being fulled.

3. A new article of manufacture comprising a papermakers wet felt for supporting and draining paper making material, said felt comprising a belt-like woven structure having relatively hard twisted warp yarns running lengthwise thereof and plied filler yarns running transversely thereof, said filler yarnshaving their individual fibres substantially untwisted about their own axes, said filler yarns each comprising a pair of singles yarns S twisted together into plied yarn form, each of said singles yarns comprising card roping .Z twisted in opposite direction into singles yarn form, said woven fabric being fulled.

4. A papermakers wet felt for supporting and draining paper making material, said felt comprising a woven fibre structure having relatively hard twisted warp yarns running lengthwise thereof and plied filler yarns running transversely thereof, said filler yarns having their individual fibres substantially untwisted about their own axes, said filler yarns each comprising a pair of singles yarns twisted together in plied yarn form, each of said singles yarns comprising card roping twisted into yarn form, said Woven fabric being fulled.

5. A new article of manufacture comprising a papermakers wet felt for supporting and draining paper making material, comprising a woven structure having relatively hard twisted warp yarns and filler yarns running transversely thereof, said ller yarns each comprising a plurality of singles yarns twisted together into plied yarn form, each of said ysingles yarns comprising drafted, substantially untwistcd card roping, said woven fabric being fulled.

6. The article according to claim 5 wherein said singles yarns are twisted at a rate substantially equal t0 the rate of twist imparted to said yarns when plied, but in a direction opposite thereto.

7. The article according to claim 5 wherein said singles yarns are twisted at a rate of about 4.0 twists per inch in one directionand being twisted in the opposite direction, when plied, at a rate of about 4.5 twists per inch. Y

References Cited` in the file of this patent UNITED STATES PATENTS 1,497,068 Collingbourne June 10, 1924 2,165,772 Walsh et al. July 1l, 1939 2,208,533 Amory July 16, 1940 2,423,828 Chagnon Iuly l5, 1947 2,485,153 Henning et al. Oct. 18, 1949 2,865,409 Asten Dec. 23, 1958 2,882,933 Hindle et al. Apr. 21, 1959 FOREIGN PATENTS 472,893 Canada Apr. l7, 1951 OTHER REFERENCES Effect of Ply vTwist on Single Twist from Textile World, February 2l, 1931. Page 38,

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