US2275278A - Method of shrinking cloth - Google Patents

Description

March 3, 1942.

B. R. ANDREWS METHOD OF SHRINKING CLOTH Filed March 13, 1939 m o s u 1 w w w a T e s n .m Mn. 6 n

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"UNITED STATES PATENT'OFFICE mm: monorsnnmmocm'rn mammalian ammo ms is, me, Serb! in. 201,401 IOlahna'wLlO-lu) This invention relates to shrinking cloth and it has for its general object to provide a novel method of shrinking cloth by which the cloth may be shrunk to approximately its maximum amount in a natural way as distinguished from producing the shrinkage in the cloth by mechanically rearranging the yarn or threads of the fabric to produce the shrinkage.

It is well known that when unshrunk cloth is moistened or wetted while in a relaxed or untensioned condition, it will shrink both warpwise and weftwise. I

I have discovered that when a wet textile fabric that is not fully shrunk is being dried, the fabric has no tendency to shrink during the first part of the drying operation, but during the final part of the drying operation there is a marked tendency for the fabric to shrink. In carrying out my invention, I make use of this discovery by providing a method of shrinking cloth which consists in first wetting cloth while in a relaxed or untensioned condition, thereby to produce shrinkage thereof, and then drying the cloth in two stages, the first stage involving the portion of the drying operation during which there is no appreciable tendency for the cloth to shrink, and the second stage being the final drying operation during which there is a marked tendency for the cloth to shrink. The first stage of the drying operation is preferably carried out while the cloth is in a flat condition and under no strain either warpwlse or weftwise. This may conveniently be done by performing the first or non-shrink-producing portion of the drying operation while the cloth is mechanically supported in a straight flattened condition, as it would be in a tenter frame. The second stage of the drying operation, which is the shrink-producing stage, is carried out while the cloth is in a relaxed .untensioned condition, so that there is nothing to interfere with the shrinkage of the cloth which occurs during this final part of the drying operation. One way of carrying out the final shrinkproducing stage of the drying operation is to fioatingly convey the cloth through a drying chamber on a current of drying medium in a manner disclosed in Gautreau Patent No. 2,144,919, January 24, 1939. While thus being fioatingly conveyed the cloth is not mechanically supported but is supported entirely by the current of drying medium, that is, lt-is pneumatically supported as distinguished from being supported by mechanical means.

By the time that the first or non-.shrink-propleted, the fabric will be suillciently set or iirmed so that the ri ht .angular arrangement or the warp threads and filling threads, as well as the 'straightness of the fabric will be maintained during the final shrink-producing stage of the drying operation. in spite of the fact that this latter stage is carried out while the fabric is in a relaxed and unrestrained condition.

In order to give an understanding of my invention, I have illustrated in the drawing diagrammatically an apparatus by which my improved method can be carried out.

In the drawing: i

Fig. 1 is a somewhat diagrammatic view illustrating the improved method of drying cloth;

Fig. 2 is a graph showing the two drying stages.

In the drawing, I indicates the cloth to be shrunk, said cloth being shown as wound on a suitable roll 2.

The first step in my improved process is to wet the cloth and thereby produce shrinkage thereof.

Such wetting of the cloth may be carried out in any suitable way, but I will preferably wet the cloth to such an extent that the water absorbed thereby will be about one hundred per cent of the dry weight of the cloth, although the invention can be successfully carried out by wetting the cloth to a greater or lesser extent.

In the drawing, I have shown, merely for illustrative purposes, a wetting-out device comprising two rolls 3 and 4 between'which the cloth passes, the roll 3 being partially immersed in water 5 contained in a tank 6. Instead of using the wetting-out rolls, however, the wetting of the cloth may be done by spraying moisture on to it, or in any other desirable way.

After the cloth has been wet, it is subjects d to the two-stage drying operation, but be 40 is done, it is desirable to allow the cloth to remain in a wet condition for a sufficient time interval to permitthe water to permeate the fibres of the cloth. To provide for this, there is shown a travelling apron I on to which the cloth is delivered in a relaxed condition, said apron conveying the cloth slowly to the drying device in which the first stage of the drying operation occurs.

8 indicates a heater over which the cloth passes in its travelling movement from the wetting-out rollsto the endless apron I, this beater serving to lay the cloth evenly on the apron. The apron I is a slowly moving apron so that the cloth will be delivered thereon in a relaxed condition, and

ducing-portion of the drying operation is comthe time interval elapsing while it is being couethis veyed along the upper run of the apron 1 is sufficient to allow the moisture to thoroughly permeate the fibres of the cloth.

This operation of wetting the cloth while in a relaxed condition produces shrinkage thereof part of the shrinkage occurring when the water, is applied to the cloth at the wetting-out" rolls and part occurring while the cloth is .in'ga reill have acquired a sufiicient ts straightness, flat form and I p sement of threads during the remainder of ;th operation.

. From the'chaniber stage or non-shrinkproducing portion of the laxed condition on the travelling apron 'land'the j moisture is permeating the fibres. As a result, the cloth comesifrom the endless apron in ajfpartially shrunk condition, thefshrinkagebeihg in both a warpwise and weftwise direction. Ii

After the 'cloth has undergone the shrinkage resultingfrom its being wet, it is then subjected to the first stage or non-shrink-producing portion of thedrying operation.

. One way in which this can be accomplished is iii in a drying chamber 9. Thclothi passes from the travelling apron I over a-guide roll it drying-"operation is carriedout, thecloth is taken to a second dryin' g chamber I! in which the second andjnn'al stage on 'shrink producing portion of the drying operationis' carried'out. During I this final? stage er shrink-producingv portion of xztne drying operation, the. cloth is maintained in airelaxedg untensionedFcondition so that it is free to shrmxinfiis 'aturalwamqone way in which '315 .veyingthe; clothgt'hrough a drying chamber on a j current of-[drylng medium in a manner described I -in said 'GautreauPatent 2,144,919, the cloth reby partially drying the cloth on, a tenter frame and then enters the drying chamber 8 at i2, and; emerges from it in a partially dried condition at B, said cloth beingcarried through the drying chamber 9 ina fiat condition by the tenterframe f l0. In order to'retain in the cloth as much as .5-

possible of the shrink which was produced therein by the wetting-out process, it is desirable to g introduce the cloth into the tenter frame unden- As stated above, I have discovered vthatiiirluan cloth which is thoroughly wet is dried, ,there will be no appreciable tendency for the'cloth to shrink during the firstpart of the drying operatiombut that during the final portion of the drying operation, there will be a marked tenden'cyfor the cloth to shrink. The point in the drying operation where the tendency to shrink begins varies with difierent kinds of .cloth and different kinds of fibres, but generally speaking, when the cloth which is thoroughly wetisbeing dried, therewill be no tendency for shrinkage to occur until'sixty per cent or more of the moisture has been removed from the cloth. In some fabrics the mainingina relaxed untensioned condition as it is fioatinglyconveyed throu'ghthe drying chamber. flnaldr'yingstage. the cloth willundergo u'rlitional shrinkage and thus will emergei from the-drying hamber I! in a fully 9nit1o .i.-

de so iicthe' or v u: I f v @theedrying, operation, fatically its'sole support I As the othkcome's i'romc-the chamber vll, wound ie;.

'velof the cloth from the drying chamthe drying llwill'be so contoq-pro'vide cloth between the g m asshownat ll, 80, toavoid subjecting the cloth toany appreciable warpwise tension in its travelling movement.

- Fig. 2 is a graphillustrative of my improved method'fof shrinking cloth. The horizontal line It. indicates the per cent of water in the cloth,

, and 'thelipyerticallineflilindicates the loss of area 1 by shrinkage. 'Iheinclinediineli illustrates the shrinkage which occurs as the water is applied to the cloth} it being assumed that the amount of shrinkage during the fi'nal drying operation may} not begin until as much as eighty per cent or more of the moisture has been removed from the fabric.

In carrying out my invention, therefore, the

thoroughly wet cloth I is first partially dried in a" drying chamber 8 while it is mechanically sup-' ported in a mat condition, as for 'instanceJn a tenterframe III or by some other supporting means, the drying being continued untila point is reached where the fabricbegins to The conditions for drying in the drying chamber;

9 may be so regulated, according to the character of the cloth, by any known or usual means .8 to dry the cloth to this desired extent. While; 1

the cloth I is held in a fiat condition inthe tenter frame Ill during the first stage of the drying operation, 'yetit is not held under tension or stretched so that when the cloth is delivered from the drying chamber il, it will have the same po'-: tential shrinkage which it had when it entered the chamber. During this first or nonshrinkproducing stage of the drying operation, the cloth t will preferably'be held in the tenteri'rame or by water absorbedby the cloth is'one'hundred per cent oi the weight of the cloth. The loss of area or shrinkage which occurs atzthis time is indicated by the distance a, b. While the cloth is in a relaxed condition on the apron ,l and the water; is thoroughlypermeating' the fibres, an additional shrinkage will'occur but without any change in, the moisture content in the cloth, this g, additional shrinkage being indicated by the distance 1;, a.; the first stage of the drying operationgin the chamber 8, the cloth will undergo no shrinkage and this part of the drying operationisrepresented by the horizontal portion 23 of the drying 24,; The second r s uns-9'.

gthe .d ylnijlbperation 'is in'-.

producini stage dicate'dv by the.

esteemed"?! of the line 24 i 'flll f ll Fh i e ISW Z' e e' e an addition'alfis'hrinkage or; loss of area'in thecloth 111- dica'ted 'by'" the distance ii d. on the vertical line'lil. I

'I'he .-point 2i inifth'e wliere thef l'a tter han es from thei straisht -portion il 'to the ur-W ?-fi ibe'sflfw ll' ew-w din r ni ki ofvcloth and "fclothflmadei oi' different fibreslbut the' graph shown 'inkFlg. 2Iillust'rates the manner in which the shrinkage occurs ::in' carrying out my improved method.

- =With m invention, theQentire shrinking operation ,ofrjthe cloth is carried out in anatural way and without resorting tojany mechanical treat; ment or the cloth by which its threads are rearranged to produce the shrinkage thereof. The

shrinkage which-the cloth obtains according to my method has a high degree of permanency and is not lost by ironing during subsequent laundering operations nor by tension that may be applied to the cloth during subsequent manufacturing operations.

Iclaim:

l. The method of shrinking cloth which con- 4. The method of shrinking cloth which consists in producing an initial shrinkage of the cloth by wetting the same, subjecting the cloth sists in wetting cloth thereby to produce shrinkage thereof, subjecting the wet cloth while mechanically supported in a flat condition to a partial drying operation which is continued only so long as the drying proceeds without any tendency for the cloth to shrink, and then producing additional shrinkage in the cloth by completing the drying thereof while it is in a relaxedcondition by floatingly conveying the cloth through a drying chamber on a current of drying medium.

2. The method of shrinking cloth which comprises wetting the cloth while in a relaxed condition, thereby securing shrinkage thereof, subjecting the wet cloth to a partial drying operation while it is in a tenter frame and free from warpwise tension and continuing such partial drying operation during the time that removal of moisture from the cloth is not accompanied by a tendency for the cloth to shrink but terminatin such partial drying operation before a point is reached at which further removal of moisture is accompanied by a tendency of the cloth to shrink, and producing additional shrinkage in the cloth by completing the drying operation whfle the cloth is in a relaxed, untensioned and unrestrained condition.

3. The method of shrinking cloth which comprises wetting the cloth while in a relaxed condition, thereby securing shrinkage thereof, partially drying the wet cloth ina tenter frame without subjecting it to warpwise tension and continuing the partial drying during the time that removal of moisture from the cloth has no tendency to shrink the latter but terminating such partial drying before the drying operation has been carried to a point where further removal of moisture from the cloth will be accompanied by a tendency of the cloth to shrink, and then producing-additional shrinkage in thecloth by completing the drying operation by floatingly conveying the cloth through a drying chamber on a current of drying medium.

while in a tenter frame and free from warpwise tension to a drying operation which is continued during the time that removal of moisture from the cloth has no tendency to shrink it but which is terminated before the drying operation has reached a point where further removal of moisture from the cloth will be accompanied by a tendency for the cloth to shrink, and producing additional shrinkage in, the cloth by completing the drying operation while the cloth is in a relaxed condition both warpwise and weftwise.

5. The method of shrinking cloth whichconsists in wetting the cloth thereby to produce shrinkage thereof and then drying the cloth by performing the non-shrinking portion of the drying operation while the cloth is held in a fiat condition by shrink-resisting means, and performing the shrink-producing portion of the drying operation with the cloth in a relaxed unrestrained condition.

6. The method of shrinking cloth which consists in wetting the cloth thereby to produce shrinkage thereof and then drying the cloth by performing the non-shrinking portion of the drying operation .while the cloth is mechanically held in a flat condition but free from tension sufficient to obliterate to any appreciable extent the shrinkage which the cloth experienced by the wetting operation, and performing the shrinkproducing portion of the drying operation by floatingly conveying the partially dried cloth through a drying chamber on a current of drying medium.

7. The method of shrinking cloth which consists in wetting the cloth without applying any appreciable tension thereto in a warpwise direction, thereby producing shrinkage in the cloth, and then drying the cloth by performing the nonshrinking portion of the drying operation while the cloth is held in a flat condition by'shrink-- resisting means but under no appreciable tension, and performing the final or shrink-producing portion of the drying operation while the cloth is in a relaxed unrestrained condition, thereby producing additional shrinkage in the cloth.

BERNARD R. ANDREWS.

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