US2072138A - Making of pulp rovings, yarns, and twines - Google Patents

Description

'March 2, 1937. J. c. SHERMAN MAKING OF PULP ROVINGS, YARNS, -AND TWINES Filed March 4, 1956 v- @www '35 show for progressive Patented Mar. 2, 1937 UNITED STATES PATENT OFFICE John C. Sherman, Attleboro, Mass. Application March 4, 1936, Serial No. 66,986

18 Claims.

This invention relates to the conversion of paper-making pulp into rovings and thence into stout yarns and twines comparable in physical characteristics to cotton-products of like weight.

I begin with the formation of very thin ribbons of Wet pulp and subsequently roll and twist these up While progressively dewatering them.

Such ribbons are best formed on a cylindermold type of paper-making machine, the cylin- 1'0 drical wall of which is unperforated except along selected, narrow, parallel circumferential drainage zones. Such a cylinder-mold is shown inthe United States Patent #603,333, of May 3, 1898, to C. Kellner, though I prefer to t it with an internal suction-quadrant such as will be hereinafter noted.

When a paper-making screen is placed around such a mold, pulp will form into ribbons only over the circumferential drainage zones. By carrying an endless screen around less than the complete circumference of the mold and letting it extend beyond the mold, one may obtain from the operation of the mold a pluralityof spaced wetpulp-ribbons lying upon the screen for further.

treatment.

Such ribbon, so formed, may normally contain about nine parts of water to one of fibre, by weight and is here defined as having a water-tobre ratio" of nine-to-one. Other degrees of wetness will be hereinafter defined in like manner.

But pulp of the stated wetness is much too wet to be roved, (i. e., rolled up on itself in preparation for spinning). Hence the means I shall dewatering are of the essence of my invention.

My ribbons must be so formed that in general their component bres shall lie 'more or less lon- ,gitudinally of the ribbons and the ribbons. when ,io-dried, shall preferably caliper only from one to two thousandths oi' an inch in thickness.'

Any materially greater thickness makes the subsequent spinning operation less effective. I therefore begin with a paper-making pulp hav- 5 ing only about from three to ve pounds of bre in ten thousand pounds of water and run the cylinder-mold very fast.

By applying suction to the cylinder mold I may now form ribbons having a water-to-bre ratio m of about nine to one.

My pulp ribbons, when rounded up (as ,will be described) will be hereinafter called rovings; and for best results I prefer to convert the ribbons into rovings when their water-to-Iibre ;5 ratio has come down to about o ne-to-one as in that event my resulting yarns wm ne bulky and softer than if rounded up while burdened withv excess water.

The progressive dewatering which I shall describe is vital since, with the nine-to-one ratio 5 my ribbons do not react well to the roving operation and-even if so roved-cannot be collected in roving cans or on spools .or the like without .undergoing deformation through. the mutual pressure of superposed turns or coils because of 1o the dead weight of their excess water-content. Furthermore, in spinning the rovings, their excess mass from large water-content increases the frequency of their breakage and requires an expensive slowing down of the spinning operation. 16 By the means to be hereinafterv disclosed I secure for each step of the conversion process the appropriate degree of progressive drying.

In the drawing these means are conventionally shown in a manner sumcient, with the context, 20 to enable anyone skilled in the textile and papermaking arts involved to carry out my invention.

Fig. 1 shows conventionally in longitudinal elevation the apparatus I prefer to use.

Fig. 2 showsan alternative system of drying 25 which may replace, as indicated, the corresponding details of Fig. 1.

In Fig. 1 a. source of pulp-stock is shown at l,

' delivering through pipe 2, past valve 3, to the vat 4 in which may be a baille-plate 5. This vat 30 has no right-hand-end-wall and its vertical side walls terminate on the right in an arcuate curve 6 adapted to abut upon the endless screen 'I which runs around the cylinder mold 8 for a distance less than the circumference thereof. The cylinder mold is internally iltted with a xed suction-quadrant dotted at 8a through which water from the vat is drawn by suction through the outlet 9. 'Ihe pulp ribbons are formed upon the screen 1, and one of them is shown stippled 40 at I0. As the screen passes over a stationary suction box Il the ribbons become slightly compacted as shown at la. 'I'he suction box is evacuated through the suction-outlet I2. Because of the peculiar formation of the cylindermold, as already described, the pulp which would ordinarily be formed in a wide sheet now forms in separate, parallel-lying ribbons, and the ribbon lll to be here followed through the ensuing description is typical of the one hundred or more such ribbons on'the apparatus.

On leaving the top of the suction box H-the employment of which isI optionalthe screen 'I carries the pulp ribbons in their partially' dewatered form I 0a directly into the heat of in- 55 candescent material which, in the drawing, consists of flaming gas from the gas-jets I3, I3, etc. The ribbons leave this heated area in a still more dewatered form Illb and are carried by the screen over the rollers I4, i4, the screen tli'en returning to the cylinder mold, passing on its way under the shower-pipe I5 and over and under the guideand-take-up rolls I6, I6. As the screen passes downward under considerable tension over rollers I4, I4, a suitable frame (not shown) carrying rollers I1, I1 with an endless belt (of Wire, leather or other material) stretched on these 'rollers is brought into proximity to the screen 1 to bring after be called the rubbing device.

I cause these rollers I1, I1, to oscillate on their axial linesthat is, in a plane perpendicular to that of the. drawing in a to-and-fro motion of one-quarter inch or less amplitude. 'Provision shouldbe made by suitable cam-action to control this amplitude. One or both of the rollers I1 must be so driven as to maintain the speed ofthe belt substantially equal to that of the screen. 'This rubbing action changesthe ribbons into rovings, which emerge at Iilc to be swept up onto the first of a series of festoon rods, I9, I9, etc., of a festoon dryer.

It will be understood that the screen 1 is of considerable length so that the wet ribbons shall be exposed to the llames of the jets I3 for from one to three seconds. To indicate this construction I have broken the drawing on the vertical dotted double line :rz-x.

Similarly, the festoon dryer to be now described is of substantially extension, to suggest which I have broken the "drawing of it on the vertical dotted lines y-y` and z-z. The festoon rods may be elevated by a chain system shown dotted at 20 and carried by rollers 20a, 20a, 20h of which 20h may be the driving roller. The rods may then be transferred to a horizontal track-system 2| of relatively rapid motion, said system returning over idler 20c; the rods vthence transferred to the slower track-system 22 which may be driven by driver 20d. The rods may then be transferred to a descending elevator chainsystem 23 driven by driver 20d and spaced over idlers 20c, 20c. Therovings shown entering the festoon in partially dewatered form, as at I0c, emerge as at Id suihciently dried to be caught up on a. warp beam or spool 24 or spread out laterally and distributed among numerous individual collectors of like form. scraping blades D and D' may be applied to the screen 1 and the belt I8.

Fig. 2 showsan alternative-form of apparatus beginningon the line E-E--E of Fig. 1, and is to be regarded as a substitution of the parts shown for those of Fig. .1 'w the .right oi that line, similar reference letters and numbers applying to both figures.

` In Fig. 2 the screen 1 is lengthened so that after it has passed the rollers I4, I4 it continues in a free curve 1a until it rests on one or. more table rollers 28a, thence continuing over additional batteries of flame, I3, i3, thence over table rollers 26h, thence over rollers 21, 21 and in irlctional contact with driving roller 25 whence observed that I may rapidly reduce the watercontent of the pulp-ribbons on their way from the cylinder mold to the rubbing device from a waterto-bre ratio of nine-to-one to a ratio of one-toone by exposing them to a blue-flame gas re Without injury to the fibres ifvsuch exposure is very brief. With small, thickly massed gas jets placed directly under the screen the wet ribbons will endure exposure to flame of from one to three seconds without charring. With Athe suction box II in use (whereby the water-to-bre ratio can be reduced by suction alone to three-to-one) I may shorten the period of name-exposure to from one to one and a half seconds; and, with the screen moving forward five hundred feet a minute, the stretch of name-bathed screen need not exceed 12 feet.

By the means illustrated and described the excess water is violently driven oi from the bre `without need of subjecting the ribbons to any one uses the additional suction means II. Inasmuch as the success of my invention lies in the subsequent intertwisting of individual fibres, and this in turn is contingent upon their lying more or less longitudinally of the ribbon, it is evident that I must, `by preference, do as much drying by ame and as little by suction as conditions permit, since suction cannot twist but only jumble the bres.

Within the general range of time-intervals stipulated above, it is found that the incident heat is utilized to (so to speak) explode and drive o i the water without raising the temperature of the ribbons or the screen to a harmful extent; but if by chance such heat is held upon an element of the screen for a time long enough to drive oil? al1- the protective water-content (say, ve seconds) the ribbons burst into flame and the screen is soon ruined. Therefore it is essential that the gas-jet valves be so yoked to the motive apparatus of the screen that, upon stopping or slowing down the machine, the gas jets shallsink instantly to mere pilot-jet size, or else that protective shutters be interposed between the jets and the screen in emergencies. l

Apparently my flame-drying effect reaches first the supercial water within the ribbons, and does not remove all the water which is, so to' speak, entrapped upon or within individual flbres as the so-called water of hydration. The proc\ ess as described eliminates the undesired excess of water, instantaneously conditioning the ribbons to be rubbed and rounded while their constituent fibres are still limp and responsive to such rubbing and rounding operations.

As the screen 1 leaves the cylinder mold it carries no continuous iilter-mat or web of ilbres covering its surface but carries only narrow spaced longitudinal bands or ribbons of pulp. If the attempt be made to dewater these ribbons by suction alone, then the uncovered stretches of the Screen tax the capacity of the suction pump and suction, so impaired, sufllces so to dewater the ribbons that they may be formed into rovings and also to rid the open meshes ofthe screen from water, water will still ow from the ribbons themselves into these meshes between the ribbons, resulting in a continuous redistributionof free water. If, in the act of rounding up the, ribbons in the rubbing device, free .water is so interchanged any single droplet`accumulated and passed again V into a ribbon often causes a local weakness and either causes the roving toA break or to split longitudinally. By my present invention not only is the ribbon adequately dewatered but the screen itself is effectively -freed from excess water.

Further, if wet pulp is dried by powerful suction upon a screen, fibres-especially the relatively long ne bres required for textile usestend to become entangled upon and within the screen structure, and my ribbons are too narrow and too thin to endure much stress from such entanglement. Hence I use suction sparingly and avoid crushing or matting the iibrous mass.

Further, in the prior art, rovings-formed with an excessive water content have been too weak for conveyance from the rubbing device to any distant collecting means since no such rovings take on adequate strength until spun. This trouble isalso eliminated b'y my present invention.

Furthermore, the iiame I prefer to use actually tends to lift the wet ribbons from the screen, this effect serving to facilitate the removal of the rovings from the screen since it eliminates entanglement of individual iibres by the screen. The simultaneous production of a large number oi' very iine rovings in closely spaced parallel lines onscreen 1 is easy, but the subsequent conveyance of these in unbroken lengths calls for care, and the apparatus outlined in Fig. 2 is best suited to cope with the problems incident to conveyance when one is making rovings to be formed into yarns of #12 or iiner count as reckoned on the established scale for cotton yarns. Such yarns take on great stoutness when twisted or spun but are tender in their unspun condition.

The natural tendency of the rovings is `to fall free from the rubbing device, and in Fig. 2 they fall in contact with the free-curving stretch 1a of the screen which gently cradles them as it conveys them to the horizontal position over the second battery of ames I3, I3. Since it is necessary to sustain this free curvature 1a without avoidable vibration one or more table rolls of which one is shown at 26a may be located adjacent the curved stretch, and one or more similar rolls 2Gb lying under the horizontal stretch of the'screen will augment the steadying eiect.

The second exposure of the rovings to arnes as in Fig.'2'is preferably either' briefer or less intense than the iirst exposure since inthis latter phase the rovings -now have an insuilicient water-con.- tent to save them from injury through prolonged or too intense heat.

My rovings may be collected in various ways, as in roving cans or warp beams or on spools or creeis but-except when the rovings are dropped into cans-the linear speed of reeling up must be in step with the delivery speed of the production-process. It is further desirable, in collecting the rovings, to conserve their remaining water-content since stout yarns are best formed from rovings still wetted with their original water,and intermediate drying and rewetting do not make for best results.

The unbroken formation and collection of my 'This consideration is weighty in relation to the desired festoon-drying. 1 My rovings may enter the festoon with a relatively low water-content and be so much the better fitted to endure suspension without elongation.

While not limited to the use of a cylinder-mold, since I may alternatively use a fourdrinier type, I prefer to usea cylinder-mold iltted with the type of internal suction shown in U. S. Patent #1,758,167, of May 13, 1930 to W. H. Millspaugh as best ensuring that the ilbres shall be iished from the pulp endon, and a suitable surfacing cylinder'for such device (to take the place of the usual screen-surface) is described above and las shown in suiiicient detail in the above-named U. S. patent to Kellner.

The specications and drawing herein contained are submitted as descriptive of my preferred types of apparatus and not as implying limitations beyond thel requirements of the prior art.

I am indiilerent as to the furnish of pulp materials used, and fillingand/or sizing ingredients are at the users option. MyA invention contemplates vthe use of chemical wood-pulp alone or in admlxture with ground wood, or Aany other type of pulp whether free or slow since I do not depend on suction' alone for its dewaterment prior to roving. In fact for very stout yarns I may by choice employ a rather slow pulp for the sake of the important qualities it may have to ensure the :drm interbonding of component libres, though in general a slow pulp militates against softness of roving and/or yarn. Y

Similarly, as regards the source of incandescent heat, while naked flame is best, I may substitute for the batteries of gas jets a system of horizontally disposed pipes containing ilowing NS uid, such being the commercial name of a mixture of univalent and trivalent metallic chlorine salts fluent when heated and capable of sustaining without sensible pressure on its confining conduit a temperature of 1500 degrees Fahrenheit.

The heating and' circulating oi' such fluid is, however, inconvenient, and does not provide for my rovings that uprush of blazing gas which I regard as'the especial merit of my,v gas dames.

Similarly, as to the rubbing device, I may, in a slow-moving apparatus, dispense with the belt I 8 andthe lowermost of the rollers I l, letpulp-ribbons and rovings be not carried to extremes...A In fact, such yarns may greatly exceed in tensile strength the cotton yarns chosen for" comparison, but at the same time they may be deficient in softness and pliability.. If, however, the control of the gas flames be suitably altered to carry the dewatering slightly further, yarns comparable in tensile strength to cotton and of satisfactory softness can be' made.

It is with these reservations in mind thatI have hereinbefore deilned the median rangeof water-to-ilbre ratios which I regard as most con# sistent with average results, Without implying any limitation of the validity of my claim to patentability. With this reservation of rights, I claimz- Y 5,1'. A method ofvforming a pulp roving for conversion into yarn consisting in iirst forming upon a foraminous carrier a ribbon oi' pulp with a water-to-ilbre ratio of at least nine to one, in then dewatering this ribbon by suction to a water-tobre ratio of about three to one, in then further dewatering the ribbon by exposure to naked ilame until its water-to-ilbre ratio drops to about one to one, in then rubbing the ribbon laterally,

to form a roving, and in then further dewatering the roving.

2. A method of forming and conditioning aA pulp roving which consists in this sequence of operations: (l) forming a fibrous pulp of a water-to-flbre ratio of about ten thousand to four; (2) forming upon a foraminous carrier a ribbon of said pulp having a water-to-ilbre ratio of said ribbon by suction to about three to one; (4) further reducing the water-to-fibre ratio to about one to one by exposing the ribbon while it lies upon said foraminous carrier to uncovered ilan'ies; rubbing the ribboninto la rod-like form; (6) further dewatering the rubbed ribbon.

3. A method of forming yarns from chemical wood-pulp which consists in first preparing an aqueous suspension of paper-making materials including such pulp, in then forming upon a foraminous carrier from said materials a ribbon having a water-to-bre ratiov of about nine to one, in then reducing this ratio by suction to about three to one, in then dewatering the ribbon by direct exposure to flame until its waterto-flbre ratio is about one to one, in then rubbing it while still upon the carrier until it assumes the form of a roving, and in then further dewatering the roving.

y 4. A method of forming yarns from papermaking pulp which consists infrst forming from said pulp a. plurality of ribbons positioned in parallel alinement upon a foraminous carrier, in removing by suction a portion of their contained water, in then further dewatering them by exposurelto ame, in then rubbing them all simultaneously to individual rovings by the friction o! a rubbing device while they lie upon said carrier, and in then further dewatering them.

5. In the formation of pulp rovings these sequent steps: Iorming upon and longitudinally of the screen of'a paper-making machine a plurality of spaced parallel-lying pulp ribbons; then partially dewatering said ribbons by suction, and

. degrees Fahrenheit.

them 'to naked flame while they rest upon said screen.

6. In the making of pulp rovings the formation from water-dispersed paper-making material upon a foraminous carrier of a plurality of spaced parallel-lying pulp ribbons; the partial dewatering of said ribbons by suction; the further partial dewatering of said ribbons by exposing them to llame while upon said carrier...

an'd the withdrawal of said ribbons upon said carrier from the ame While they still contain sufcient residual water to prevent their ignition.

'7. A method of forming pulp rovings and conditioriing them for spinning consisting in this sequence of operations:(1) forming from dilute paper-making pulp upon a foraminous carrier a plurality of parallel-'lying ribbons substantially as described and having a high-water-content; (2) reducing the water-content of said ribbons by direct exposure to heat of incandescence; (3) withdrawing said ribbonsv uponv said carrier beyond the reach of said heat while they still retain sufficient water to prevent their destructive distillation by said heat; (4) rubbing said ribbons while they are -upon said carrier into the form of rovings.

8. A method of forming pulp rovings and conditioning them forv spinning consisting in this sequence of operations: (1) forming from paper- .making pulp upon an endless foramin'ous carrier a plurality of parallel-lying ribbons substantially as described and having a high water-content, (2) reducing the water-content of said ribbons by brief exposure to heat above the charring temperature of their dry-brous content, (3) removing the ribbonsupon the carrier from the heat while they still contain enough water to prevent their Abecoming charred, (4) rubbing the ribbons upon the carrier.

9. A method of forming pulp rovings and con--y ditioning them for spinning consisting in this sequnce'of operationsz-(l) forming from paper-making pull upon an endless foraminous carrier a plurality of parallel-lying ribbons substantiallyv as described and having a high watercontentv (2) reducing the water content of the of incandescence.

' 10. Apparatus substantially as described comprising in combination an endless foraminous carrier, means for progressively depositing on said carrier separate ribbons of wet pulp, means for partially dewatering said ribbons by brief direct exposure to heat of a higher degree than 500'degrees Fahrenheit, means for rubbing the partly dewatered ribbons into the rounded form oi' rovings, and means for further dewatering said rovings.

11. Apparatus substantially as described comprising in combination an endless Ioraminous carrier, means lfor progressively depositing on said carrier separate ribbons of wet pulp, means for partially dewatering said ribbons by brief exposure to heat of a higher degree than 500 degrees Fahrenheit, means for rubbing the partly dewatered ribbons into the rounded form of rovings and means for again briefly exposing the rovings to heat of a higher degree than 12. An instrumentality for the partial de- IWatering of wet pulp ribbons comprising in combination an endless foraminous carrier for the ribbons, a closely-adjacent source of incandescent heat, and means for progressively withdrawing said ribbons upon said carrier from the zone of said heat.

13. Mechanism substantially as described comprising in combination a vat containing an aqueous suspension of paper-making materials, a suction-cylinder-mold coacting with said vat, said cylinder mold being perforated to permit the drainage of water into its interior over narrow spaced circumferential zones, an endless foram inous carrier passing over said cylinder-mold and receiving upon its surface deposits of partially compacted pulp ribbons, means for subjecting said ribbons to the heat of incandescence, and means for rubbing-up said ribbons upon said carrier into the form of rovings.

14. Means for converting wet ribbons of paper-making pulp into rovings consisting in combination of a foraminous carrier whereon said ribbons'move rapidly and continuously forward, a source of incandescent Iheat closely adjacent to said carrier, and means for rubbing said ribbons upon said carrier into the form of rovings immediately upon their emergency from the locus of said heat.

15. As a step in the process of delivering and conditioning Wet pulp rovings -to be spun, the conveyance of said rovings in spaced parallel rows upon a foraminous carrier, said carrier moving through a free-swinging arc from a downwardly-moving to a substantially horizontally-moving position, said rovings remaining upon said carrier during their partial dewaterment and being then progressively removed from said carrier for collection.

16. As a step in the formation of rovings from initially wet pulp ribbons upon a foraminous carrier, the Ysubjection of said wet ribbons initially and brieiiy to the full incidence of incandes-v cent heat and their subsequent subjection to the ,modifed incidence of such heat.

17. As a step in the formation of rovings from initially wet ribbons of pulp upon a foraminous carrier, the subjection of said wet ribbons initially and briey to the direct incidence of naked flame through the apertures in said foraminous carrier and their subsequent subjection tothe incidence of ilame of lesser intensity through said apertures.

18. In the preparation of initially Wet pulp ribbons for spinning, these sequent steps:-(1) the brief subjection of said ribbons to incandescent heat while they are suiiiciently wet to ensure their immunity from injury by said heat; (2) their conversion into rounded rovings by rubbing and (3) their then being partially dried on a festoon drier at a temperature substantially less than that of incandescence.

JOHN C. SHERMAN.

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