US2811351A - Method and apparatus for fluid treatment of textiles - Google Patents

Description

H. H. BELCHER Filed June 26, 195s INVENTOR. H. BE Lc HER ATTORN EVS Oct. 29, 1957 METHOD ANDAPPARATUS FOR FLUID TREATMENT 0E TEXTILES United States Patent O METHOD AND APPARATUS FOR` FLUID TREATMENT F TEXTILES Harold H. Belcher, Orange, Mass.,

Hunt Machine Company, of Massachusetts assiguor to Rodney Orange, Mass., a ycorporation This invention relates to methods and apparatus for handling continuous running lengths-lof materials such as textiles and more particularly to methodsand apparat'us for moving such materials at high speed through a fluidbath in a substantially tensionless condition.

Asis well known in the art textile materials, in the conversion from raw to finished goods, are subjected to a number of physical and chemical treatments, such as washing, bleaching, dyeing and the like which involve the exposure of the fabrics to a fluid bath. In modern practice,ba'tch.processes have been ydiscarded in favor of the muchfaster continuous processes in which the fabric is m'ovedthrough the fluid bath in the form of a-continuous web. Inl such processes the fabric is ordinarily moved over one or more upper and lower roll sets, the latter being'immersed in the fluid hath, and the `fabricis removedfrom the treatment chamber by a pair of nip rolls provided at the outlet end of the'treatment chamber.

In' such wetV treatments the fabrics. may tend to shorten or elongate.. Consequently, if allA p'ortionsof the running length of the fabric are moved mechanically throughthe bath at a' constant speed, mechanical stresses arise in the fabric which may injure thefabric or prevent effective uniform treatment or, in the case of heavier fabrics, impose injurious stresses upon theY mechanical apparatus for moving the web.

Many prior efforts have been directed toward the provisionk of apparatus for automatically compensatingfor variations in length of the moving web to eliminate or minimize the mechanical stresses in the fabric and ad- Vance' the web in la susbtantially tensionless condition. `The most effective known prior efforts to solve these problems are disclosedin Patents 2,474,717 and 2,618,142, the former being capable of handling materials in open width or rope form and the latter being particularly adapted for handling either relatively narrow webs or webs which are hunched laterally and commonly known as rope goods.

In each of these patents, tension in the cloth is minimized through the use of a bottom roll or roll's which are rotated at a speed suchk that their peripheral surfacev speeds are greater than the linear speeds of the fabric passing over the` lower rolls.

The desired action in each of these patents depends upon lslippage between the fabric Iand the bottom rolls when the fabric tension is low, the tension automatically providing suihcient traction on the fabric to equal the total resistance to cloth progression. Thus, the tension in the fabric while maintained at a relatively low value inthe apparatus of each of the above mentioned patents nevertheless must be suicient to overcome the resistance of the fabric to motion induced by mechanical friction and inertia of the fabric and the liquid carried bythe fabric.

, 'Inf the apparatus of Patent 2,474,717 mechanical fric- Y tion which retards the web is produced by travel ofthe fabric. over the stripper bar which been found; neces- Patented Oct. 29, 1857 ICC 2r sary to overcome the tendency of the fabric ltoadhereto or wrap around the lower roll and hy the friction member which is deliberately used to retard the speed of the upper rollers to induce tension in the fabric to. avoid overrunning or tangling and from the friction of the upper rolls.

In the apparatus of Patent 2,618,142, friction is produced by the similar stripper bar and also by contact of the fabio withl guide bushings and pins which are necessary to guide the fabric in a helical path around the upper andlower rolls. Also in the apparatus of that` patent, friction is introduced bythe passage ofthe fabric over the upper rolls or bars which is minimized but. notelimi.- nated by expensive upper roll construction consisting" of a plurality of independently mounted spools.

Ithas long beeny known in the art that the stabilityv of a tensionless webhandling system depends on thereduction of traction as tension is reduced so. that overfeedy of cloth does not occur to the point of building up an accumulation or pile of cloth at the exit side of the roll. For this reason, it was universally believed, prior to the present invention, that it was necessary to overdrive the bottom roll; Since the top roll is subjected'. to the Weight of cloth which yprovides sutlicient traction so that overa feed occurs even with no tension beyond the weight of the cloth the necessity for overdriving the lower roll can be definitely estahlishedin the case of dry cloth which is to be moved at'. slow speeds.

However, I have discovered, contrary to present practice, that, by overdriving the upper rolls the fabric web may be'movedthrough'arfluid bath at high speeds while subjecting the fabric to tensions Iappreciably below those produced by any known prior apparatus.

This action depends upon the dynamics of the web fabric moving at high speeds which having heretofore either :been overlooked or. misunderstood. I have discovered that when wet cloth-is moved at high speed, the magnitude of theretarding effects of the friction caused by the passage of the fabric through the fluid bath, the resist-ance tol motionv caused by the difference between the weight of the uptravel strand full of fluid and the weight of the downtravel strand stripped of excess; fluid and the power consumed in accelerating thev water upwardswith the uptravel strand is'quite large as compared with the cloth weight effects and that' slippage overl` an ovendriven top roll occurs as tension decreases and before overfeeding of the cloth occurs. The tendency for slippage tov occur before overfeed is augmented by the centrifugal force which throws the cloth away from theztop roll reducing both the'arc of contact and the pressure against the roll.

In accordance with another aspect of my invention. I have discovered'that the resistance to movementxof4 the fahricV and consequently` the tension required to moverit through a fluid bath in a helicalk path in' the-manner shown in Patent 2,618,142. can be further substantially' reduced by the elimination of friction between thetclothandthe guide bushings and pins between the upper and lower rolls. This is acomp'lished by inclining: theaxis of one of the rolls, preferably the hottomroll, with. respect. to thelaxis of the other of the rolls so that theadvance of each*v loop is produced by the geometric relationshipfof the rolls rather than by mechanical guide structure. Guide pins may be used', if desired, to prevent excessive wandering of the cloth. However, the pressure of the cloth against the pins andconsequently the friction on the cloth is minimized; Y v g It is accordingly the major purpose and object ofthe present inventionto provide novel methods and apparatus for moving continuous webs of textiles and the likeat 'in a helical path.

It is also an important object of the invention to provide 'novel methods and apparatus for moving fabric webs at high speed through a fluid bath lwhich increase the uniformity and effectiveness of the fluid treatment,

It is a further object to provide novel methods and apparatus for advancing a fabric web at high speed through a fluid bath at substantially reduced tension by the utilization in a novel manner of the dynamics of the moving web.

These and other objects are accomplished by rotating the upper rolls at a surface speed exceeding the linear speed of the fabric passing over the roll and by disposing Athe upper and lower rolls in a novel relationship in which Vthe axes of the rolls are angularly related to provide an Vautomatic substantially frictionless feed, as will become apparent as the description proceeds in connection with the accompanying drawings in which:

Figure l is a front elevation of a preferred form of the apparatus constructed in accordance with the present invention; and

Figure 2 is an end elevation of the apparatus of Figure l.

The present invention is primarily adapted for use in the handling of fabrics in rope form and it has been found vthat for washing, bleaching and other fluid treatments the -substantially tensionless feeding of fabrics in rope form greatly improves the fluid treatment. So long as the fabric progresses through the apparatus in substantially tension less form there is a certain amount of ballooning and contracting action which seems to improve the penetration of the uid into the fabric and thus enhance the washing, vbleaching or other action. The novel threading features of my apparatus are not however limited to fluid treatments or to the handling of fabrics in rope form but are equally adapted to the handling of narrow dry webs or tapes.

Referring now more particularly to drawings, in-

dicates a vat for holding treating fluids such as dye liquor,

bleaching agent or a washing iluid. The vat 20, which may be of any conventional design and per se forms no part of the present invention, is ordinarily lled with the treating fluid to the level indicated at 22. The uid may be supplied through a conventional pipe connection 24 and overowed through a pipe 26 to provide a counterflow of the treating uid. The vat 20 is provided with one or more access doors 28 to permit manual handling of the fabric when necessary and to permit inspection and repair of the apparatus within the vat.

Rotatably mounted in corrosion resistant bearings 30 and 32 which may be mounted externally or internally of the vat below the level of the fluid 22 is a lower roll 34 which may be of any suitable form and is preferably formed of non-corrosive material such as stainless steel. It will be noted that the bearing 32 is disposed above the bearing 30 so that the axis of the roll 34 is disposed at .an angle to the horizontal for a purpose to appear. A

similar upper roll 36 is mounted for rotation about a horizontal axis in bearings 38 and 40.

A nip roll housing 42 is mounted on the upper surface l i of the vat 20 by any suitable means and contains conventional nip rolls 44 and 46 journalled in the respective 'vide a constant rate of advance.

upper and lower bearing sets 48 and S0. The nip rolls are of conventional construction and preferably are resiliently pressed together for squeezing the fabric as it exits from the treating apparatus. The lower nip roll 46 is driven by any suitable means such as an electric motor 52 and frictionally drives the upper nip roll 44. Drive is also transmitted from the motor 52 to the upper roll 36 through the lower nip roll shaft, a pulley 54 mounted thereon and a belt or chain 56 which passes over a pulley SSvmounted on the projecting end of the upper roll shaft.

The nip roll housing and the main vat are in open communication so that the fluid squeezed from the fabric will be returned to the main vat.

The apparatus thus far described is particularly suited for handling a continuous running length of material, indicated by the broken line W, which may be either a narrow at web or fabric in rope form. The web W enters the apparatus through an eyelet 60 which is located at one end of the vat substantially at the level of the top of the upper roll 36. The web then passes lover the upper roll 36 downwardly into the fluid bath under and around the lower roll 34 and successively around the upper and lower rolls and is iinally withdrawn from the vat by the nip rolls and exits from the apparatus through the eyelet 62.

It is a feature of the invention that both threading and advancing of the fabric in operation are accomplished automatically because of the relation of the axes of upper reached the right end of the apparatus, the elastic connection is removed and the free end passed through the nip rolls and the eyelet 62. The mechanism having been thus automatically threaded is ready for high speed operation. In operation, the web continues to follow the path established by the initial threading.

The automatic lateral advance vof the web is due to the fact that as the web leaves either of the rolls it tends to approach the other of the rolls at right angles to the axis of the latter. Accordingly, the rate of advance is determined by the relative inclination of the axes of the two rolls. YBy proper selection of the relative inclination of the two rolls by inclining the lower roll, the upper roll, or both, the fabric may be caused to advance at a predetermined rate without the use of guide pins or bushings. For example, assuming that the roll axes are sixty inches apart at the center of the machine and that a six inch cloth advance is desired at this point, the angle of vend is 6.48 inches and at the low end 5.52 inches. This variation in advance rate will not adversely affect the operation yof the machine. However, uniformly spaced light guide pins 64 mounted on a pivoting rail 66 may be swung into position after threading, if desired, to pro- In the example given, such pins would deflect the fabric only .48 inch from its natural path. Pins spaced in accordance with the natural advance of the web may be used to prevent excessive wandering of the cloth. Thus, even when the guide pins are used, the frictional contact between the web and the guide pins is minimized and the pins which are subjected only to low stresses may be of light, inexpensive construction. 1

While the automatic advance of the web and the elimination of the friction producing guide pins and bushings substantially reduces the tension in the fabric web, the

tributes in large measure to the minimization of the web fabric and thesurface speed of the upper roller. As stated` above,=I` have discovered that when, contraryy toprior practice, the surface speed of the upper roll exceedsvthe linear speed of the adjacent fabric, the tension in the web is reduced below the minimum values heretofore thought obtainable.

The linear speedof the fabric is established primarily bythelspeed ofthe nip rolls 44 and 46 which withdraw the fabric from the apparatus. However, the actual linear speed of the web at any given point within theV apparatus may be appreciably above or below the linear speed'established by the nip rolls because of the shrinking or stretching of the fabric as it passes through the uid bath. The

fabric may stretch at one point and shrink at another, thereby producing wide variations in the linear speed of the fabric from point to point through the apparatus. I have discovered that such variations in the linear speed of the web whether uniform or non-uniform do not produce tension anywhere in the fabric beyond that necessary to overcome its resistance to progression through the bath as long as the surface speed of the upper roll exceeds the maximum linear speed of the web at the upper roll. The differential between the surface speed of the upper roll and the linear speed of the fabric ordinarily is not critical and thus does not require close control nor a change of speed ratios between the upper roll and the nip rolls for different fabrics having differing susceptibilities to stretch and shrink.

Where desired, a graduated overdrive may be obtained by the use of a tapered upper roll. Also, the relative speeds of the upper roller and the nip rolls may be obtained by introducing a conventional variable speed drive between them.

It has been found that the overdrive of the upper rolls combined with the inclination of the lower roll is suicient to reduce the web tension to a value which will normally prevent damage to modern fabrics regardless of the wet process to which they are subjected. However, the tension in the apparatus may be further reduced if required in special instances by driving the lower roll 34, which is herein disclosed as an idler roll, either at the same peripheral speed as the upper roller 36 or at a speed such that its peripheral speed approximates the linear speed of the fabric. However, if the lower roll is overdriven, stripper bars must be employed which may largely nullify the advantage gained from the overdrive.

The presently described apparatus is effective when operating at high linear web speeds such as present day commercial speeds of 100 to 300 yards per minute. At this speed the three factors of water friction, water lift and water acceleration provide sulicient retarding action to prevent overfeed of the cloth but at the same time the forward propelling eect of each contact on the top roll effectively progresses each loop of cloth to the point of minimum tension.

This reduction in web tension, in addition to decreasing the stresses imposed on the apparatus and eliminating the possibility of injury to the fabric, also relaxes the fabric and permits increased ballooning, This assures maximum exposure of the fabric to the treating uid, thus reducing the required immersion time and promoting uniformity of the treatment.

From the foregoing it will be apparent that I have attained the above stated objects of the invention by the provision of a new and improved method and apparatus for the high speed tensionless handling of webs of material. The apparatus is extremely simple in construction and the rolls are of simple one-piece construction which can be manufactured and replaced when required at minimum expense. By the elimination of many parts heretofore used in apparatus of this kind the expense of the mechanism has further been decreased and the power required to produce a given linear fabric speed has been consequently reduced.

Y The iinvention-may` be embodied' in other. vsp'eciiicfor-ms vwithoutdeparting from' th'e 'spirit or essential characteris;

- tics thereof. Forexamplewhile'I have shown an apparatusi for passingA a running length of material through a iiuidbath in a helical path itis tobe understood that the invention has equal application to an apparatus having a series of upper andl lower rolls over which the moving web is successivelyv passed as sh'own for. example in Patenti 2,474,717; TheI present embodiments are ltherefore'to be considered in all respects as illustrative and not restrictive,the scope of the invention being` indicated bythe4 appended claims rather than by the foregoing de'scrp'tiongandfall.changes which come within the meaning andf range ofV equivalency of Athe claims i are v therefore intended-tobe embraced therein. i

What is claimed and desired to be secured by United States Letters Patent is:

1. A method for moving a continuous fabric web through a liquid bath at high speeds, which web may change in length during its passage through said bath, comprising the steps of removing said web from said bath at a predetermined linear speed, supporting said web over said bath in a series of downwardly concave loops, and applying a frictional rotary force to said web at said loops at a speed in excess of said predetermined linear speed by an amount exceeding the maximum variation in speed of the material resulting from the change of length of said web so that the drag resulting from withdrawal of the web from said bath exceeds the friction between said web and said force.

2. Apparatus for the high speed iiuid treatment of an elongated fabric web which may change in length during treatment, comprising an enclosure adapted to contain a treating fluid, means for removing said web from said enclosure at a predetermined linear speed, upper roller means above the uid contained in said enclosure for supporting a portion of said web within said enclosure in a series of downwardly concave loops, lower roller means positioned within Vthe, lower portion of each loop, and means to drive said upper roller means at a peripheral speed exceeding said predetermined linear speed by an amount exceeding the maximum variation in speed of the material resulting from the change of length of said web so that said upper roller means slip forward relative to the adjacent portions of said web regardless of the variations in the length of said web.

3. The apparatus as dened in claim 2 wherein the axes of the upper and lower roller means are angularly related and lie in the same vertical plane.

4. The apparatus according to claim 3 wherein the axis of the upper roller means is horizontal and the axis of the lower roller means is inclined with respect thereto.

5. Apparatus for moving a continuous fabric web at high speeds through a liquid bath comprising a container for a fluid bath, upper and lower roll means; the lower roll means being located within the container and the upper roll means being located above and in spaced rela\ tion to said container, the web passing over the upper roll means and under said lower roll means through the apparatus, pulling means for withdrawing the web from said apparatus and means for rotating the upper roll means at a peripheral speed which materially exceeds the linear speed of the fabric web coming from the container such that the drag on the fabric web coming from the container exceeds the friction between the web and the upper roll means, whereby said upper roll means slips forwardly relative to said web.

6. Apparatus as defined in claim 5 in which the upper and lower roll means consist of single rolls whose axes lie in the same vertical plane and in which the web passes over the upper roll and under the lower roll helically along said rolls.

7. Apparatus as defined in claim 6 in whichone roll is inclined toward the other in the direction of the pulling means.

7 8. .At method for moving a continuous fabric web through a liquid bath at high speed, which web may change in length during its passage through said bath, comprising the steps of introducing said web into said bath, removing said web from said bath at a predetermined linear speed, supporting said web in a series of downwardly concave loops over said bath with depending portions of said web immersed in said bath, and advancing said web by contacting the inside of said loops above said bath with a member moving at a peripheral speed materially exceeding the maximum linear speed of the web of the loop which it contacts to create a sliding frictional drive between said loop and` said member, the peripheral speed of said member exceeding any linear speed imparted to said web by change in length.

UNITED STATES PATENTS Gwynne Dec. 21, Forrest Feb. 15, Moritz V Apr.,18,- Van Derhoef et al. Dec. 24, Lely et al. May 26, Gram May 25, Belcher June 28, Heyer Mar. 25, Belcher et al. Nov. 18,

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