CA1112005A - Method and apparatus for moisture conditioning of compressively treated fabric - Google Patents
Method and apparatus for moisture conditioning of compressively treated fabricInfo
- Publication number
- CA1112005A CA1112005A CA300,339A CA300339A CA1112005A CA 1112005 A CA1112005 A CA 1112005A CA 300339 A CA300339 A CA 300339A CA 1112005 A CA1112005 A CA 1112005A
- Authority
- CA
- Canada
- Prior art keywords
- fabric
- moisturizing
- moisture
- further characterized
- zone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004744 fabric Substances 0.000 title claims abstract description 239
- 238000000034 method Methods 0.000 title claims abstract description 58
- 230000003750 conditioning effect Effects 0.000 title description 2
- 230000003020 moisturizing effect Effects 0.000 claims abstract description 52
- 230000008569 process Effects 0.000 claims abstract description 52
- 238000011282 treatment Methods 0.000 claims abstract description 17
- 239000003595 mist Substances 0.000 claims abstract description 15
- 239000000835 fiber Substances 0.000 claims abstract description 5
- 238000001035 drying Methods 0.000 claims description 29
- 239000007921 spray Substances 0.000 claims description 21
- 230000000694 effects Effects 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims 1
- 230000006872 improvement Effects 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 17
- 230000000979 retarding effect Effects 0.000 description 8
- 230000009471 action Effects 0.000 description 5
- 238000010276 construction Methods 0.000 description 4
- 238000010025 steaming Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005755 formation reaction Methods 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- 238000000889 atomisation Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003086 colorant Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000009699 differential effect Effects 0.000 description 2
- 238000010981 drying operation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 239000004909 Moisturizer Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000010960 commercial process Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000001333 moisturizer Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06C—FINISHING, DRESSING, TENTERING OR STRETCHING TEXTILE FABRICS
- D06C21/00—Shrinking by compressing
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
- D06B1/00—Applying liquids, gases or vapours onto textile materials to effect treatment, e.g. washing, dyeing, bleaching, sizing or impregnating
- D06B1/02—Applying liquids, gases or vapours onto textile materials to effect treatment, e.g. washing, dyeing, bleaching, sizing or impregnating by spraying or projecting
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06C—FINISHING, DRESSING, TENTERING OR STRETCHING TEXTILE FABRICS
- D06C2700/00—Finishing or decoration of textile materials, except for bleaching, dyeing, printing, mercerising, washing or fulling
- D06C2700/13—Steaming or decatising of fabrics or yarns
- D06C2700/135—Moistening of fabrics or yarns as a complementary treatment
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Treatment Of Fiber Materials (AREA)
- Drying Of Solid Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The disclosure relates to a finishing treatment for fabrics, particularly tubular knitted fabrics, having at least some natural fiber content, where the fabrics have been given a compressive shrinkage treatment by an asymmetrical process, some-times referred to herein as "burnish compacting", in which one side of the fabric is acted upon differently than the other. The process and apparatus of the invention eliminate or minimize "two sidedness" in the appearance of the fabric, which otherwise can be particularly noticeable with respect to colored fabrics. After passing through an asymmetrical compressive shrinkage process, the fabric is conveyed in a tension free manner through a moisturiz-ing station, in which moisture is sprayed on the opposite surfaces of the fabric in the form of an extremely fine fog or mist, in quantities greater than the natural moisture regain of the fabric after compacting. The thus-moisturized fabric immediately enters a so-called Palmer-type dryer, in which the fabric is held against a steam-heated drum by means of a porous blanket. Significant improvement in the opposite side uniformity of the fabric is obtainable by the process.
The disclosure relates to a finishing treatment for fabrics, particularly tubular knitted fabrics, having at least some natural fiber content, where the fabrics have been given a compressive shrinkage treatment by an asymmetrical process, some-times referred to herein as "burnish compacting", in which one side of the fabric is acted upon differently than the other. The process and apparatus of the invention eliminate or minimize "two sidedness" in the appearance of the fabric, which otherwise can be particularly noticeable with respect to colored fabrics. After passing through an asymmetrical compressive shrinkage process, the fabric is conveyed in a tension free manner through a moisturiz-ing station, in which moisture is sprayed on the opposite surfaces of the fabric in the form of an extremely fine fog or mist, in quantities greater than the natural moisture regain of the fabric after compacting. The thus-moisturized fabric immediately enters a so-called Palmer-type dryer, in which the fabric is held against a steam-heated drum by means of a porous blanket. Significant improvement in the opposite side uniformity of the fabric is obtainable by the process.
Description
In the processing of many fabrics, particularly knitted fabrics in either tubular or flat form, many of the significant commercial finishing techniques involve the application of length-wise mechanical compressive shrinkage to the fabric by processes which may be regarded as~asymmetrical, in that one side of the fabric is acted upon at least somewhat differently than the other side. By way of example, one of the important commercial processes for the compressive shrinkage of tubular knitted fabric, the "Compax" process, involves directing the fabric into a compacting zone formed in part by feeding and retarding rollers rotating at slightly different speeds. The fabric is being introduced into the zone at the speed of the feeding roll and is being decel-erated in the treating zone to the speed of the retarding roll.
As the fabric passes between these two rollers, it is being acted upon simultaneously by rollers moving at different surface speeds, ; so that at least one of the rollers is moving relative to the fab-`~ ric. One surface of the fabric thus may become slightly "burnished"
so that it may appear slightly more shiny than the opposite sur-face. This is referred to as "two sidedness".
Two sidedness resulting from asymmetrical compressive shrinkage treatment, sometimes herein called burnish compacting is more pronounced with colored fabrics, and of course may be more troublesome in connection with fabrics processed in tubular form, where one side of the fabric tube constitutes the same "surface"
as the other side of the tube (e.g., both the top and the bottom surfaces of a fabric tube may constitute the outside surface of a garment).
In some cases, asymmetrical processing of the fabric is at least partially compensated by treatment of the fabric in two stages, such that any burnishing action is applied to one surface in the first stage and to the opposite surface in the second stage.
By appropriately proportioning the amount of compressive shrinkage effort applied at the respective stations~ it may be possible to - 1 - ~
substantially balance the surface appearance of the fabric. Never-theless, even using a two station machine, some two sidedness may result, either because it is not practical to balance it out altogether, or because the desired proportioning of effort in order to achieve balance of appearance may not be consistent with optimum balance of effort for achieving the desired total compres-sive shrinkage effort. Moreover, in some cases the fabric itself (e.g., ribbed fabrics) may be of a nature such that its appearance can be changed undesirably during compressive shrinkage treatment, as by reason of the thickness compression of the fabric, as well as any burnishing action.
In accordance with the invention, two sidedness and other undesired effects in mechanically compressively shrunk fabric may be greatly improved by a new moisturizing treatment, in which significant amounts of moisture are imparted with great uniformity of distribution to the opposite surfaces of the fabric, following , compressive shrinkage treatment, after which the fabric is immedi-ately directed into a Palmer-type dryer, in which the fabric is ; held in a geometrically stabilized condition against the heated surface of a dryer drum, by means of a porous conveyor blanket.
Upon emergence from the discharge end of the Palmer-type dryer, the fabric is in a finished condition, with significantly improved surface appearance, both from the standpoint of two sidedness and/
or thickness compression (as in the case of a ribbed fabric).
Moisture is applied to the opposite sides or surfaces of the fabric in an extremely finely divided spray mist or fog, under conditions that reliably avoid the formation of droplets, which might spot or mark the fabric. The amount of moisture to be applied to the surface of the fabric is somewhat empirical for different fabrics, but in any event is greater than that which could possibly be achieved by either steaming of the fabric or by natural moisture regain. In this respect, steaming of the fabric may add approximately two percent or so moisture by weight, whereas s natur~al moisture regain with time may add about six percent. In contrast, in some cases, with light fabrics subjected to substantial compressive shrinkage treatment, it might be appropriate in the .
process of the invention to add surface moisture constituting up to fifty percent by weight of the fabric.
The rate of moisture application to the fabric, for a given speed of travel of the fabric, is set such that the fabric will have been adequately dried by the time it emerges from the Palmer-type dryer. The spray mist application is set to be applied ; 10 at a constant rate, and the amount applied to the fabric therefore will vary as a function of the speed of travel of the fabric through the misting zone. An operator of the process observes i the fabric emerging from the Palmer-type dryer, and the process can be progressively speeded up until the emerging fabric evidences undesirable two sidedness, after which the processing speed may be slowed down slightly, so that a greater amount of moisture is ; applied to the fabric as it travels to the misting zone. Expe-rience with the process indicates that restoration of the desired surface appearance of the fabric is to a great extent a function of the amount of moisture applied to the surface of the fabric, such that, once a constant rate of spray application has been established, excellent control over the process may be achieved by simply controlling the speed of travel of the fabric through the spraying-drying sequence. The spraying and the drying at all times remain in balance, because whenever the fabric speed is reduced to enable more moisture to be applied, its speed of passage through the dryer is correspondingly reduced, and vice versa, so that the drying effort is at all times consistent with the amount of moisture application.
An improved apparatus arrangement is provided for the uniform application of spray mist to the opposite surfaces of a moving fabric web, so that highly controlled amounts of moisture may be applied to opposite sides of the fabric, with consistent reliability, free of condensation spots or the like. It will be understood, of course, that the opposite "sides" of a tubular fabric will be the same surface. Thus, wherever reference is made herein to opposite sides or opposite surfaces of a fabric, such reference will be understood to mean the outside surface of a tubular fabric or the two surfaces of an open width fabric, as the case may be.
....
The fabric is conveyed in a completely tension free manner between opposed banks of spray nozzles, directed at the respective opposite surfaces of the fabric. Each bank of nozzles consists of a series of relatively closely spaced fine-atomizing spray nozzles extending across the full width of the fabric and ~ arranged to discharge an air-atomized fine mist of moisture on the ;; fabric surface. To accommodate the inevitable starting and stopping of the process from time to time during otherwise continuous pro-duction runs, means are provided for muffling the spray discharge of the nozzles during stoppage of the processing line, so that the nozzles do not have to be turned off. In this respect, stopping and starting of the air-atomizing nozzles may be occasioned by momentary sputtering and discharge of larger-than-desired drop-lets of moisture, which could otherwise spot the fabric.
For a more complete understanding of the above and other features a~d advantages of the invention, reference should be made to the following detailed description illustrating the invention and to the accompanying drawings.
Fig. 1 is a box flow diagram illustrating the fundamental steps involved in the process of the invention.
Figs. 2a and 2b constitute a simplified representation illustrating a processing line for carrying out the process of the invention.
Fig. 3 is a top plan view illustrating an advantageous form of apparatus for the application of spray mist to the fabric.
surfaces in the quantities and with a uniformity consistent with the requirements of the process.
Fig. 4 is a cross sectional view as taken generally on line 4-4 of Fig. 3.
Figs. 5 and 6 are enlarged, cross sectional views of the encircled areas A and B of Fig. 4O
Fig. 7 is a cross sectional view as taken generally on line 7-7 of Fig, 6.
Referring now to the drawings, the schematic flow diagram of Fig. 1 indicates the basic steps involved in the process of the invention. First, there is the asymmetrical mechanical com-; pressive shrinkage procedure which, for the purposes of this appli-cation, may be referred to as "burnish compacting". The term "burnish compacting" is indicated to encompass various forms of compressive shrinkage treatment, whether or not performed in two or more stages, in which, in any one stage, the fabric is treated differently on one surface than on the other. Typically, this results in a rubbing action on one surface of the fabric, giving a slight polishing or burnishing effect. Commercially significant examples of burnish compacting procedures are reflected generally in the Eugene Cohn et al. Canadian Patents No. 640,199, NoO 657,405, and No. 640,266. Other processes, such as that reflected in the Walton et al. United States Patent No. 3,869,768, will impart differential action to the opposite surfaces of a fabric and would thus constitute burnish compacting within the meaning of that term as used in this application. In general, the term "burnish com-pacting" is intended to cover rather broadly processes for the compressive shrinkage of fabrics, in either tubular or flat form, and either of knitted or other construction, in which one of the surfaces of the fabric is affected differently than the other, either because of differential action in /~he compressive shrinkage equipment itself, or because of the fabric construction.
The terms "surface moisturizing" as referred to in the flow diagram of Fig. 1, refers to the application of a fine fog . .
or mist spray to the surface of the fabric on an extremely finely divided, highly uniform basis. The term "stabilized drying"
~ refers generally to drying of the moisturized fabric with heat, ; while maintaining the geometric stability of the fabric, as by the use of a Palmer-type dryer, for example, as distinguished from an air jet dryer.
~ With reference more particularly to Figo 2, the process ;~ of the invention includes a compactor stage 10 which, in the specifically illustrated example, may be generally in accordance with the Eugene Cohn et al. Canadian Patent No. 640,266. To that ` end, the compactor includes a spreader stage 11 for receiving tubular knitted fabric and distending it laterally to a pre-determined, uniform width. The thus distended fabric is passed through a steaming stage 12, and then is discharged directly into a compacting station 13, consisting of respective feeding and retarding rollers 14, 15, and a confining shoe 16. The fabric enters the compacting station substantially at the surface speed of the feed roller 14. However, as it encounters the retarding roller 15, at a pressure nip formed by the respective opposed rollers 14, 15, the retarding roller exerts a superior grip on the fabric, and its movement is retarded substantially to the speed of the retarding roller. In the region where the feeding and retarding rollers are directly opposed, the lower surface, in the case of the compacting station 13, is slightly burnished by the slipping action of the feed roller 14.
The fabric F, now partially compacted by the station 13, enters a second compacting station 17, which likewise consists of a feed roller 18, retarding roller 19 and confining shoe 20, in this case oriented upside down with respect to the previous station 13. The arrangement is such that the burnishing action of the second station feed roller 18 is applied to the upper sur-face of the fabric 16, whereas it is applied to the lower surface in the upstream station 13. In the absence of ideal results, rarely achieved in practice, the mechanically preshrunk fabric issuing from the second stage compacting station 17 may have some degree of two sidedness, meaning that one surface will appear to be different than the other. The two sidedness effect will, of course, be more pronouned where the burnish compacting is performed in a single station machine, as will be readily appre-ciated. Moreover, the effect, although physically probably no different, is more noticeable with colored fabrics than with white fabrics and is more noticeable with darker colors than with lighter colors.
In general, the burnishing effect resulting from burnish compacting of a fabric does not appear to result from a fundamental change in the structure of the fabric, but rather from a temporary change in its surface characteristics. In time, through normal use, washing, drying, handling, etc., such two sidedness probably would disappear. In the meantime, however, it represents a significant impediment to sale and use of the fabric, where there is a pronounced two-sided appearance.
In accordance with the present invention, fabric dis-charged from the burnish compacting stage, is conveyed over a speed control roller 21, including appropriate photoelectric detectors, by which the speed of the burnish compacting operation is controlled automatically, in relation to the speed of the moisturizing and drying operations to be described, so as to maintain the fabric in a relaxed condition on the discharge side of the compactor. This is accomplished by detecting the limits of a loop L in the fabric, so that the speed of the compacting operation is increased as the loop diminishes and is decreased as the loop enlarges.
The roller 21, which may be referred to as the speed control roll, operates at the basic speed of operation of the line, including the moisturizing operation and the drying stage, and this speed is set by the process operator with a suitable variable s speed control. Fabric leaving the discharge side of the roll 21passes under a guide roll 22 and into the lower portion of a moisturizing chamber 23, through an appropriate opening 24 (Figo 4) provided for that purpose. The fabric then travels in a generally upward course, at an angle of approximately 30 or 40 through the chamber. While passing through the moisturizing chamber 23, the fabric F, which is maintained in a relaxed, tension free condition and in a relatively quiescent state except for its forward motion, is sprayed on both surfaces with a fine fog or mist of water.
Immediately upon leaving the spray chamber 23, the moist fabric is supported and conveyed by a belt 26 of a Palmer-type dryer 28 (Fig. 2b). The belt passes over guide rollers 25, 27 and carries the fabric into contact with the outer surface of a large diameter dryer drum 29, heated internally by steam to a temperature of, typically, about 150 C. In the illustrated arrangement, the dryer belt 26 is formed of relatively heavy, stable but porous material and is maintained under suitable tension.
The belt thus presses the surface-moistened fabric firmly against the outer surface of the heated drum 29, while the belt and the fabric travel together, along with the rotating drum. After passing completely around the drum, the belt 26 and fabric 16 pass around a guide roll 30, and the fabric is then conveyed by the belt to the rear of the dryer stage, where the fabric is gathered, either by winding into a finished roll 31 or by means of a suitable fold-er (not shown). After releasing the treated fabric, the dryer belt 26 passes about a second drum 32, which serves to drive off excess residual moisture from the belt, and the belt then returns back to the entry guide roll 25 to receive further incoming fabric.
As reflected in Figso 3-7, the moisturizing chamber 23 desirably consists of an open top tank 33, advantageously having side and end walls 34-37 and a bottom wall 38, but preferably with no top. A drain 39 is provided in the bottom to remove collected excess moisture. Upper and lower banks of nozzles ~5 40, 41 are located in the tank, respectively above and below the path of the fabric 16 through the chamber. The banks of nozzles each consist of transversely disposed header pipes 43, 44 to which are physically mounted a series of atomizing nozzles 45, 46, arranged with flow passages of the nozzles communicating with the interior of the header pipes 43, 44.
Although the invention is not limited thereto, the spray nozzles 45, 46 may to advantage be "Sonicore" atomizing nozzles, as currently made available commercially by Sonic Development Corp., Upper Saddle River, New Jersey. These nozzles are air-atomizing water spray nozzles which, according to the manufacturer, are so designed that atomization of the water is enhanced by a sonic energy field. Typically, atomizing air is supplied to the nozzles through the manifold pipes 43, 44, and the nozzles are supplied individually with water, through individual supply lines (not shown) each of which may be adjusted by an individual .
regulator valve, such that uniform discharge and atomization of the water may be achieved across the entire bank of nozzles. In the illustrated apparatus, transverse nozzle spacing may be on the order of 7-8 cm, across the working width of the spray chamber 23, which may be slightly greater than the maximum width of fabric to be accommodated in the processing line.
As reflected in Fig. 4, the upper bank 40 of spray nozzles is arranged to spray downward and to the rear, at an angle of 45 or so to the horizontal, while the lower nozzle bank is arranged to project upward and forwardly, at a generally similar angle.
The adjustment of the nozzles, in terms of rate of flow, is typically such as to apply to the surfaces of the fabric a total of about two and a half ounces of moisture per square yard of fabric, when the fabric is advancing through the moisturizing chamber at a rate of approximately 14 meters per minute. When the nature of the fabric and/or the extent of the compressive shrinkage treatment enables satisfactory optimization of the fabric ~$~L2~
appearance with the application of a lesser amount of water, the advance of the fabric through the moisturizing-drying stages is speeded up, so that the fabric spends less time passing through the range of the misting nozzles, in which case correspondingly less moisture is applied.
A concomitant of speeding up the fabric movement, of course, is that the fabric spends less time on the dryer drum 28, and this is in fact desirable since there is less moisture on the fabric to be driven off. Speeding up or slowing down of the rate of fabric advance thus forms an ideal technique for control of the process, once a desirable balance is achieved between the time rate at which moisture is applied to the fabric and the capacity of the dryer 28 to remove that moisture. An operator at the dis-charge end of the dryer can simply inspect the fabric for possible two sidedness or other correctable conditions, and continue to increase the rate of advance of the fabric, as long as the fabric appearance remains within specifications. In some cases it may be possible to operate the process at speeds up to 36 meters per minute, using a relatively small Palmer-type dryer, processing light weight fabric which has been only moderately (eOg., 8%) compacted. In general, the capacity of the burnish compacting stage 10 is in all instances well in excess of the capacity of the dryer, such that there is no problem involved in controlling the compactor stage to respond appropriately to speed variations in the moisturizing-drying stage.
In the moisturizing stage, the amounts of moisture typically applied to the fabric surface are considerably in excess of those amounts customarily applied to fabrics during conventional finishing treatments. In all events, the moisture applied is greater, usually significantly so, than the maximum amount of moisture that could be imparted by application of steam (about 2%, by weight) and/or by natural moisture regain with time (about 6%
by weight). Because of the significant amounts of moisture to be applied, the area in the immediate region of the nozzle banks 40, 41 is laden with finely divided mist or fog, and special care must be taken to avoid the formation of droplets of moisture condensate - at locations from which the droplets could fall onto the fabric and form a water spot. To this end, the lower nozzle bank 41 and its supporting structure are arranged to be located entirely below the path of the fabric 16, so that any condensate formations merely drop to the bottom of the tank. Beneath the upper nozzle bank 40, there is provided a condensate shield 48, which extends from one side of the tank to the other and has a V-shaped collecting groove 49 inclined downwardly from the center thereof toward the opposite side walls 34, 35 of the tank. Any condensate falling from the nozzle bank 40 is caught by the shield 48 and drains down the in-clined troughs 49 toward the tank side walls. Immediately adja-cent to the walls, small gaps 50 are provided, enabling the collected water to drain down the sides of the tank~ In this connection, the maximum width capacity of the fabric is somewhat less than the width~of the tank, and typically corresponds to the width of the nozzle banks 40, 41, as reflected in Fig. 3, such that condensate guided off to the sides of the tank does not affect the fabric. In a similar manner, the front wall 36 of the tank may be provided with a condensate trough 54 (Fig. 4) above the entrance opening 24, so that any condensate forming on the inside front wall of the tank is collected and guided off to the sides.
Although the process and apparatus of the invention are intended to be substantially continuous, inevitably there are many occasions that require temporary stoppage of the process line for short times during normal operations. When such stoppages occur, it is of course necessary to immediately discontinue the application of moisture to the fabric surface to avoid excessive wetness. One way of achieving this is to shut off the supply of water to the nozzles. However, experience has shown that, whenever the nozzles are shut off and re-started, there is inherently some amount of sputtering of the nozzles. This can result in water spotting of the fabric, which is of course highly undesirable~
Accordingly, instead of shutting off the nozzle banks are muffled, whereby the nozzles are permitted to continue to discharge, but the atomized water is immediately trapped and drained away without contacting the fabric and without creating a misty atmosphere which could either condense on the fabric or on surfaces of the moisturizing chamber 23 in a manner to create a potential water spotting problem.
Both the upper and lower banks 40, 41 of atomizing nozzles are mounted for pivotal movement as by providing for limited rotational movement of the manifold pipes 43, 44,as reflected particularly in Figs. 5 and 6. During a temporary stoppage in the processing line, the manifold pipes 43, 44 may be rotated in a direction to tilt the respective banks of nozzles 45, 46 downwardly behind shield plates 48, 51. Mounted on each of the shield plates is a muffle strip 52, 53 of porous sponge arranged either to extend in a continuous strip across the working width of the shield or in individual sections located in alignment with the respective nozzles 45, 46. The positioning of the sponge elements 52, 53 is such that, when the nozzle banks are retracted to the broken line positions shown in Figs. 5 and 6, by rotation of the manifold pipes 43, 44, the nozzle tips depress the material of the sponge, permitting adjacent areas of the sponge to deform around and embrace the orificearea of the nozzleO Accordingly, as the atomizing nozzles continue to discharge atomized water, the discharge is emitted directly into the sponge muffle strips 52, 53. The atomized water is thus instantly condensed within the sponge, as it issues from the nozzle. Water of course accumulates within the sponge muffle elements 52, 53, but as soon as the sponges are saturated, the water flows from the bottom of the sponge, along the lower flanges of the shields 48 9 51 and into the bottom of the collecting tank 33. When the process is resumed again, after a temporary stoppage, it is merely necessary to tilt the nozzle-mounting manifold pipes 43, 44 back to their normal positions, so that the atomized discharge from the nozzles is directed at the fabric surface. The described muffle arrangement also facilitates initial start up of the line, as the nozzle banks may be activated while in the retracted positions and operated briefly to clear the lines and nozzles to avoid sputtering on the fabric itself.
The system of the invention is advantageous in connection 10 with the finish processing of mechanically compacted fabric, where it is desirable to restore surface characteristics of the fabric after the compressive shrinkage treatment. The process is intended for and is useful to greatest advantage in connection with asymmetrical burnish compacting techniques, such as described herein, although it also has possible application in other finishing treatments in which the fabric surface is temporarily affected (as by crushing, for example).
The invention involves the application to the processed fabric of significant quantities of surface moisture, in an 20 extremely finely divided, uniformly distributed state, free of discrete, large droplets or the like, that might cause water spotting, and in amounts significantly greater than is possible either through steaming operations or through natural moisture regain. The fabric, with its surfaces thus substantially moisturized is then conveyed through a stabilized drying process, during which the surface moisture is driven from the fabric while the fabric is s maintained in a geometrically stable condition, as by being confined between a heated dryer drum and a tensioned conveyor belt. During the drying procedure, the surface-applied moisture on the fabric 30 is vaporized, driven slowly through the confined fabric and then released to the atmosphere. During the relatively extended period in which the fabric is traveling in contact with the heated dryer drum (e.g., 15-25 seconds at typical processing speeds), the .r~
natural fibers of the fabric are fully penetrated with moisture~
The resulting effect is to substantially restore the surface appearance of the fabric, where it has been burnished and/or crushed, without significantly affecting the mechanical pre-shrinking imparted to the fabric in the upstream stage of the process.
One of the important practical features of the new process is the ease with which it may be monitored and controlled in a typical plant operation. Generally, a limiting factor is the capacity of the Palmer-type dryer to drive off moisture applied during the moisturizing stageO Accordingly, for a given nominal linear speed of fabric movement (e.g., 14 meters per minute), the rate of moisture application from the nozzle banks 40, 41 is ini-tially adjusted so that the nozzles apply as much moisture as can be removed by the dryer. Since the moisture application is essentially accomplished on a weight per unit area basis, this preliminary setup of the line is relatively independent of the character of the fabric being processed. In a practical embodi-ment of the processing line of the invention, utilizing a Palmer-type dryer with a drum of about 1.5 meters dia~eter, a properbalance of moisture application to drying capacity was realized with an application rate of about 2.5 ounces per square yard.
Having established an appropriate balance between rate of moisture application and drying capacity, the process may there-after be governed almost exclusively by simply increasing or de-creasing the rate of linear movement of the fabric through the processing line. By speeding up the linear movement of fabric, the amoun~ of moisture application per unit of area is propor-tionately decreased, as is the time spent in the dryer phase.
In general, as long as the fabric emerging from the discharge side of the dryer stage has an appearance of two sidedness or other surface characteristics sought to be eliminated, the operator can adjust the process by gradually reducing the rate of linear , movement of the fabric until its appearance is within specifications.
By thus slowing down the fabric, more moisture per unit of area is applied by the nozzle banks 40, 41, and correspondingly more time is spent on the dryer.
As can be well appreciated, different types of con-struction of the fabric will require individually different treat-ment in terms of required levels of moisture application. Likewise, some fabrics may be compressively preshrunk only to a relatively small degree (e.g., 8-10%) while others may have substantially greater compressive shrinkage, all depending on a great variety of conditions and requirements in the mill. The process of the invention, however, easily accommodates the range of such variables, through the simple control of speeding up or slowing down the linear movement of the fabric through the moisturizing and drying stages. In all cases, the speed of operation of the compacting equipment is subservient to the speed of operation of the moisturizing-drying stages. This is accomplished by sensing the size of the fabric loop 22, between the compactor stage and the moisturizer stage, and appropriately increasing or decreasing the speed of the compactor stage.
; In view of the substantial amounts of moisture applied to the fabric during the moisturizing stage, it is significant to maintain the fabric relaxed and quiescent during moisturizing and to maintain fabric geometry during drying. This is accomplished through the use of misting type spray nozzles for moisture application and a Palmer-type dryer for the drying stage. Because the fabric has been compressively preshrunk longitudinally prior to moisturizing, it is significant to the process that the moisture application be in the form of surface application rather than complete impregnation of the fabric, so that the fabric does not lose its geometric integrity while it is unsupported. After the fabric is engaged by the Palmer-type dryer and is geometrically stabilized, the moisture can fully penetrate the fabric without adversely affecting the mechanical compacting.
The spray chamber arrangement described herein has been found to be advantageous for the purposes intended, enabling significantly high amounts of moisture to be applied to the surface of the fabric, while avoiding condensation and spotting problems, and while simultaneously maintaining the fabric in a properly relaxed and quiescent state. In the illustrated arrangement, the fabric enters the open top chamber in the lower front portion, and is guided upwardly, to exit from the chamber in the upper rear portion thereof. The upwardly inclined path of travel through the spray chamber enables the nozzle banks to be conveniently and effectively located both with reference to spray application effectiveness and with respect to avoidance of condensation and drip problems. At the same time, the upwardly inclined path of travel of the fabric is advantageous from the standpoint of minimizing stress on the fabric which, when it emerges from the moisturizing zone, is both moist on its surface and laden with the weight of the moisture, so as to be particularly vulnerable to longitudinal strains. To this end, in addition, the moisturizing chamber is closely coupled with the Palmer-type dryer. Indeed, the exit guide roller for the moisturizing chamber is the entry belt guide roller to the Palmer-type dryer, so that the fabric is physically supported immediately upon its emergence from the moisturizing zone.
The process of the invention is applicable to a wide variety of fabrics, of both knitted and non-knitted constructions and of both tubular and non-tubular configuration, provided the fabric has sufficient natural or other hydrophilic fiber content to enable it to respond to the application of moisture. The process is, of course, extremely advantageous in connection with the finish processing of tubular knitted fabrics, where a relatively high percentage of burnish compacting may be applied to the fabric in a first phase of its finish processing and where uniformity of surface appearance on the top and bottom of the tubular knittedfabric web is of particular significance, inasmuch as the top and bottom constitute the same surface.
In general, the production capacity of available burnish compacting equipment is significantly greater than the linear output capacity of a Palmer-type dryer of practical size and configuration. Accordingly, overall production efficiencies may be improved in many instances by performing the burnish compacting operations separately, rather than in line with the drying operation. In such cases, the compacted fabric may be folded or otherwise gathered in a tension free condition at the discharge end of the compacting equipment. In a separate operation, two or more webs of compacted fabric may be conveyed simultaneously through a common apparatus, to carry out the moisturizing and drying sequence as described herein. Such an arrangement may be particularly advantageous where the compacted web is relatively narrow and/or where the moisturizing-drying treatment of the fabric requires a relatively low linear rate of travel through the dryer for optimum conditioning.
Thus, the invention includes a process for the finish treatment of fabrics containing at least some proportion of hydrophilic fibers, which comprises mechanically compressively shrinking the fabric longitudinally by an asymmetrical compressive shrinkage process, supplying the compressively shrunk fabric to a moisturizing zone and advancing the fabric through said zone, the improvement characterized by applying surface moisture to the fabric, during its passage through said zone, in amounts greater than the potential natural moisture regain of the fabric, and immediately thereafter directing said fabric through a drying zone and drying the fabric while maintaining the fabric geometrically stabilized.
The invention also includes apparatus for carrying out the process of claim 1, which comprises a burnish compactor, s moisturizing means forming a moisturizing zone for the application of finely divided mist to the surface of the fabric, means for guiding and advancing said fabric through the moisturizing means substantially free of lengthwise tension, a Palmer-type dryer arranged in close coupled relation to said moisturizing means, said dryer including a heated drum and a continuous conveyor belt, the improvPment characterized by said moisturizing means including a bank of finely atomizing moisture-emitting nozzles mounted in said chamber; means for controllably disabling said nozzles com-prizing a muffle shield and means for bringing said muffle shieldand said nozzles into positions in which said nozzles discharge directly into said muffle shield; and said conveyor belt being : arranged to engage and support the moistened fabric upon its dis-charge from said moisturizing means.
As the fabric passes between these two rollers, it is being acted upon simultaneously by rollers moving at different surface speeds, ; so that at least one of the rollers is moving relative to the fab-`~ ric. One surface of the fabric thus may become slightly "burnished"
so that it may appear slightly more shiny than the opposite sur-face. This is referred to as "two sidedness".
Two sidedness resulting from asymmetrical compressive shrinkage treatment, sometimes herein called burnish compacting is more pronounced with colored fabrics, and of course may be more troublesome in connection with fabrics processed in tubular form, where one side of the fabric tube constitutes the same "surface"
as the other side of the tube (e.g., both the top and the bottom surfaces of a fabric tube may constitute the outside surface of a garment).
In some cases, asymmetrical processing of the fabric is at least partially compensated by treatment of the fabric in two stages, such that any burnishing action is applied to one surface in the first stage and to the opposite surface in the second stage.
By appropriately proportioning the amount of compressive shrinkage effort applied at the respective stations~ it may be possible to - 1 - ~
substantially balance the surface appearance of the fabric. Never-theless, even using a two station machine, some two sidedness may result, either because it is not practical to balance it out altogether, or because the desired proportioning of effort in order to achieve balance of appearance may not be consistent with optimum balance of effort for achieving the desired total compres-sive shrinkage effort. Moreover, in some cases the fabric itself (e.g., ribbed fabrics) may be of a nature such that its appearance can be changed undesirably during compressive shrinkage treatment, as by reason of the thickness compression of the fabric, as well as any burnishing action.
In accordance with the invention, two sidedness and other undesired effects in mechanically compressively shrunk fabric may be greatly improved by a new moisturizing treatment, in which significant amounts of moisture are imparted with great uniformity of distribution to the opposite surfaces of the fabric, following , compressive shrinkage treatment, after which the fabric is immedi-ately directed into a Palmer-type dryer, in which the fabric is ; held in a geometrically stabilized condition against the heated surface of a dryer drum, by means of a porous conveyor blanket.
Upon emergence from the discharge end of the Palmer-type dryer, the fabric is in a finished condition, with significantly improved surface appearance, both from the standpoint of two sidedness and/
or thickness compression (as in the case of a ribbed fabric).
Moisture is applied to the opposite sides or surfaces of the fabric in an extremely finely divided spray mist or fog, under conditions that reliably avoid the formation of droplets, which might spot or mark the fabric. The amount of moisture to be applied to the surface of the fabric is somewhat empirical for different fabrics, but in any event is greater than that which could possibly be achieved by either steaming of the fabric or by natural moisture regain. In this respect, steaming of the fabric may add approximately two percent or so moisture by weight, whereas s natur~al moisture regain with time may add about six percent. In contrast, in some cases, with light fabrics subjected to substantial compressive shrinkage treatment, it might be appropriate in the .
process of the invention to add surface moisture constituting up to fifty percent by weight of the fabric.
The rate of moisture application to the fabric, for a given speed of travel of the fabric, is set such that the fabric will have been adequately dried by the time it emerges from the Palmer-type dryer. The spray mist application is set to be applied ; 10 at a constant rate, and the amount applied to the fabric therefore will vary as a function of the speed of travel of the fabric through the misting zone. An operator of the process observes i the fabric emerging from the Palmer-type dryer, and the process can be progressively speeded up until the emerging fabric evidences undesirable two sidedness, after which the processing speed may be slowed down slightly, so that a greater amount of moisture is ; applied to the fabric as it travels to the misting zone. Expe-rience with the process indicates that restoration of the desired surface appearance of the fabric is to a great extent a function of the amount of moisture applied to the surface of the fabric, such that, once a constant rate of spray application has been established, excellent control over the process may be achieved by simply controlling the speed of travel of the fabric through the spraying-drying sequence. The spraying and the drying at all times remain in balance, because whenever the fabric speed is reduced to enable more moisture to be applied, its speed of passage through the dryer is correspondingly reduced, and vice versa, so that the drying effort is at all times consistent with the amount of moisture application.
An improved apparatus arrangement is provided for the uniform application of spray mist to the opposite surfaces of a moving fabric web, so that highly controlled amounts of moisture may be applied to opposite sides of the fabric, with consistent reliability, free of condensation spots or the like. It will be understood, of course, that the opposite "sides" of a tubular fabric will be the same surface. Thus, wherever reference is made herein to opposite sides or opposite surfaces of a fabric, such reference will be understood to mean the outside surface of a tubular fabric or the two surfaces of an open width fabric, as the case may be.
....
The fabric is conveyed in a completely tension free manner between opposed banks of spray nozzles, directed at the respective opposite surfaces of the fabric. Each bank of nozzles consists of a series of relatively closely spaced fine-atomizing spray nozzles extending across the full width of the fabric and ~ arranged to discharge an air-atomized fine mist of moisture on the ;; fabric surface. To accommodate the inevitable starting and stopping of the process from time to time during otherwise continuous pro-duction runs, means are provided for muffling the spray discharge of the nozzles during stoppage of the processing line, so that the nozzles do not have to be turned off. In this respect, stopping and starting of the air-atomizing nozzles may be occasioned by momentary sputtering and discharge of larger-than-desired drop-lets of moisture, which could otherwise spot the fabric.
For a more complete understanding of the above and other features a~d advantages of the invention, reference should be made to the following detailed description illustrating the invention and to the accompanying drawings.
Fig. 1 is a box flow diagram illustrating the fundamental steps involved in the process of the invention.
Figs. 2a and 2b constitute a simplified representation illustrating a processing line for carrying out the process of the invention.
Fig. 3 is a top plan view illustrating an advantageous form of apparatus for the application of spray mist to the fabric.
surfaces in the quantities and with a uniformity consistent with the requirements of the process.
Fig. 4 is a cross sectional view as taken generally on line 4-4 of Fig. 3.
Figs. 5 and 6 are enlarged, cross sectional views of the encircled areas A and B of Fig. 4O
Fig. 7 is a cross sectional view as taken generally on line 7-7 of Fig, 6.
Referring now to the drawings, the schematic flow diagram of Fig. 1 indicates the basic steps involved in the process of the invention. First, there is the asymmetrical mechanical com-; pressive shrinkage procedure which, for the purposes of this appli-cation, may be referred to as "burnish compacting". The term "burnish compacting" is indicated to encompass various forms of compressive shrinkage treatment, whether or not performed in two or more stages, in which, in any one stage, the fabric is treated differently on one surface than on the other. Typically, this results in a rubbing action on one surface of the fabric, giving a slight polishing or burnishing effect. Commercially significant examples of burnish compacting procedures are reflected generally in the Eugene Cohn et al. Canadian Patents No. 640,199, NoO 657,405, and No. 640,266. Other processes, such as that reflected in the Walton et al. United States Patent No. 3,869,768, will impart differential action to the opposite surfaces of a fabric and would thus constitute burnish compacting within the meaning of that term as used in this application. In general, the term "burnish com-pacting" is intended to cover rather broadly processes for the compressive shrinkage of fabrics, in either tubular or flat form, and either of knitted or other construction, in which one of the surfaces of the fabric is affected differently than the other, either because of differential action in /~he compressive shrinkage equipment itself, or because of the fabric construction.
The terms "surface moisturizing" as referred to in the flow diagram of Fig. 1, refers to the application of a fine fog . .
or mist spray to the surface of the fabric on an extremely finely divided, highly uniform basis. The term "stabilized drying"
~ refers generally to drying of the moisturized fabric with heat, ; while maintaining the geometric stability of the fabric, as by the use of a Palmer-type dryer, for example, as distinguished from an air jet dryer.
~ With reference more particularly to Figo 2, the process ;~ of the invention includes a compactor stage 10 which, in the specifically illustrated example, may be generally in accordance with the Eugene Cohn et al. Canadian Patent No. 640,266. To that ` end, the compactor includes a spreader stage 11 for receiving tubular knitted fabric and distending it laterally to a pre-determined, uniform width. The thus distended fabric is passed through a steaming stage 12, and then is discharged directly into a compacting station 13, consisting of respective feeding and retarding rollers 14, 15, and a confining shoe 16. The fabric enters the compacting station substantially at the surface speed of the feed roller 14. However, as it encounters the retarding roller 15, at a pressure nip formed by the respective opposed rollers 14, 15, the retarding roller exerts a superior grip on the fabric, and its movement is retarded substantially to the speed of the retarding roller. In the region where the feeding and retarding rollers are directly opposed, the lower surface, in the case of the compacting station 13, is slightly burnished by the slipping action of the feed roller 14.
The fabric F, now partially compacted by the station 13, enters a second compacting station 17, which likewise consists of a feed roller 18, retarding roller 19 and confining shoe 20, in this case oriented upside down with respect to the previous station 13. The arrangement is such that the burnishing action of the second station feed roller 18 is applied to the upper sur-face of the fabric 16, whereas it is applied to the lower surface in the upstream station 13. In the absence of ideal results, rarely achieved in practice, the mechanically preshrunk fabric issuing from the second stage compacting station 17 may have some degree of two sidedness, meaning that one surface will appear to be different than the other. The two sidedness effect will, of course, be more pronouned where the burnish compacting is performed in a single station machine, as will be readily appre-ciated. Moreover, the effect, although physically probably no different, is more noticeable with colored fabrics than with white fabrics and is more noticeable with darker colors than with lighter colors.
In general, the burnishing effect resulting from burnish compacting of a fabric does not appear to result from a fundamental change in the structure of the fabric, but rather from a temporary change in its surface characteristics. In time, through normal use, washing, drying, handling, etc., such two sidedness probably would disappear. In the meantime, however, it represents a significant impediment to sale and use of the fabric, where there is a pronounced two-sided appearance.
In accordance with the present invention, fabric dis-charged from the burnish compacting stage, is conveyed over a speed control roller 21, including appropriate photoelectric detectors, by which the speed of the burnish compacting operation is controlled automatically, in relation to the speed of the moisturizing and drying operations to be described, so as to maintain the fabric in a relaxed condition on the discharge side of the compactor. This is accomplished by detecting the limits of a loop L in the fabric, so that the speed of the compacting operation is increased as the loop diminishes and is decreased as the loop enlarges.
The roller 21, which may be referred to as the speed control roll, operates at the basic speed of operation of the line, including the moisturizing operation and the drying stage, and this speed is set by the process operator with a suitable variable s speed control. Fabric leaving the discharge side of the roll 21passes under a guide roll 22 and into the lower portion of a moisturizing chamber 23, through an appropriate opening 24 (Figo 4) provided for that purpose. The fabric then travels in a generally upward course, at an angle of approximately 30 or 40 through the chamber. While passing through the moisturizing chamber 23, the fabric F, which is maintained in a relaxed, tension free condition and in a relatively quiescent state except for its forward motion, is sprayed on both surfaces with a fine fog or mist of water.
Immediately upon leaving the spray chamber 23, the moist fabric is supported and conveyed by a belt 26 of a Palmer-type dryer 28 (Fig. 2b). The belt passes over guide rollers 25, 27 and carries the fabric into contact with the outer surface of a large diameter dryer drum 29, heated internally by steam to a temperature of, typically, about 150 C. In the illustrated arrangement, the dryer belt 26 is formed of relatively heavy, stable but porous material and is maintained under suitable tension.
The belt thus presses the surface-moistened fabric firmly against the outer surface of the heated drum 29, while the belt and the fabric travel together, along with the rotating drum. After passing completely around the drum, the belt 26 and fabric 16 pass around a guide roll 30, and the fabric is then conveyed by the belt to the rear of the dryer stage, where the fabric is gathered, either by winding into a finished roll 31 or by means of a suitable fold-er (not shown). After releasing the treated fabric, the dryer belt 26 passes about a second drum 32, which serves to drive off excess residual moisture from the belt, and the belt then returns back to the entry guide roll 25 to receive further incoming fabric.
As reflected in Figso 3-7, the moisturizing chamber 23 desirably consists of an open top tank 33, advantageously having side and end walls 34-37 and a bottom wall 38, but preferably with no top. A drain 39 is provided in the bottom to remove collected excess moisture. Upper and lower banks of nozzles ~5 40, 41 are located in the tank, respectively above and below the path of the fabric 16 through the chamber. The banks of nozzles each consist of transversely disposed header pipes 43, 44 to which are physically mounted a series of atomizing nozzles 45, 46, arranged with flow passages of the nozzles communicating with the interior of the header pipes 43, 44.
Although the invention is not limited thereto, the spray nozzles 45, 46 may to advantage be "Sonicore" atomizing nozzles, as currently made available commercially by Sonic Development Corp., Upper Saddle River, New Jersey. These nozzles are air-atomizing water spray nozzles which, according to the manufacturer, are so designed that atomization of the water is enhanced by a sonic energy field. Typically, atomizing air is supplied to the nozzles through the manifold pipes 43, 44, and the nozzles are supplied individually with water, through individual supply lines (not shown) each of which may be adjusted by an individual .
regulator valve, such that uniform discharge and atomization of the water may be achieved across the entire bank of nozzles. In the illustrated apparatus, transverse nozzle spacing may be on the order of 7-8 cm, across the working width of the spray chamber 23, which may be slightly greater than the maximum width of fabric to be accommodated in the processing line.
As reflected in Fig. 4, the upper bank 40 of spray nozzles is arranged to spray downward and to the rear, at an angle of 45 or so to the horizontal, while the lower nozzle bank is arranged to project upward and forwardly, at a generally similar angle.
The adjustment of the nozzles, in terms of rate of flow, is typically such as to apply to the surfaces of the fabric a total of about two and a half ounces of moisture per square yard of fabric, when the fabric is advancing through the moisturizing chamber at a rate of approximately 14 meters per minute. When the nature of the fabric and/or the extent of the compressive shrinkage treatment enables satisfactory optimization of the fabric ~$~L2~
appearance with the application of a lesser amount of water, the advance of the fabric through the moisturizing-drying stages is speeded up, so that the fabric spends less time passing through the range of the misting nozzles, in which case correspondingly less moisture is applied.
A concomitant of speeding up the fabric movement, of course, is that the fabric spends less time on the dryer drum 28, and this is in fact desirable since there is less moisture on the fabric to be driven off. Speeding up or slowing down of the rate of fabric advance thus forms an ideal technique for control of the process, once a desirable balance is achieved between the time rate at which moisture is applied to the fabric and the capacity of the dryer 28 to remove that moisture. An operator at the dis-charge end of the dryer can simply inspect the fabric for possible two sidedness or other correctable conditions, and continue to increase the rate of advance of the fabric, as long as the fabric appearance remains within specifications. In some cases it may be possible to operate the process at speeds up to 36 meters per minute, using a relatively small Palmer-type dryer, processing light weight fabric which has been only moderately (eOg., 8%) compacted. In general, the capacity of the burnish compacting stage 10 is in all instances well in excess of the capacity of the dryer, such that there is no problem involved in controlling the compactor stage to respond appropriately to speed variations in the moisturizing-drying stage.
In the moisturizing stage, the amounts of moisture typically applied to the fabric surface are considerably in excess of those amounts customarily applied to fabrics during conventional finishing treatments. In all events, the moisture applied is greater, usually significantly so, than the maximum amount of moisture that could be imparted by application of steam (about 2%, by weight) and/or by natural moisture regain with time (about 6%
by weight). Because of the significant amounts of moisture to be applied, the area in the immediate region of the nozzle banks 40, 41 is laden with finely divided mist or fog, and special care must be taken to avoid the formation of droplets of moisture condensate - at locations from which the droplets could fall onto the fabric and form a water spot. To this end, the lower nozzle bank 41 and its supporting structure are arranged to be located entirely below the path of the fabric 16, so that any condensate formations merely drop to the bottom of the tank. Beneath the upper nozzle bank 40, there is provided a condensate shield 48, which extends from one side of the tank to the other and has a V-shaped collecting groove 49 inclined downwardly from the center thereof toward the opposite side walls 34, 35 of the tank. Any condensate falling from the nozzle bank 40 is caught by the shield 48 and drains down the in-clined troughs 49 toward the tank side walls. Immediately adja-cent to the walls, small gaps 50 are provided, enabling the collected water to drain down the sides of the tank~ In this connection, the maximum width capacity of the fabric is somewhat less than the width~of the tank, and typically corresponds to the width of the nozzle banks 40, 41, as reflected in Fig. 3, such that condensate guided off to the sides of the tank does not affect the fabric. In a similar manner, the front wall 36 of the tank may be provided with a condensate trough 54 (Fig. 4) above the entrance opening 24, so that any condensate forming on the inside front wall of the tank is collected and guided off to the sides.
Although the process and apparatus of the invention are intended to be substantially continuous, inevitably there are many occasions that require temporary stoppage of the process line for short times during normal operations. When such stoppages occur, it is of course necessary to immediately discontinue the application of moisture to the fabric surface to avoid excessive wetness. One way of achieving this is to shut off the supply of water to the nozzles. However, experience has shown that, whenever the nozzles are shut off and re-started, there is inherently some amount of sputtering of the nozzles. This can result in water spotting of the fabric, which is of course highly undesirable~
Accordingly, instead of shutting off the nozzle banks are muffled, whereby the nozzles are permitted to continue to discharge, but the atomized water is immediately trapped and drained away without contacting the fabric and without creating a misty atmosphere which could either condense on the fabric or on surfaces of the moisturizing chamber 23 in a manner to create a potential water spotting problem.
Both the upper and lower banks 40, 41 of atomizing nozzles are mounted for pivotal movement as by providing for limited rotational movement of the manifold pipes 43, 44,as reflected particularly in Figs. 5 and 6. During a temporary stoppage in the processing line, the manifold pipes 43, 44 may be rotated in a direction to tilt the respective banks of nozzles 45, 46 downwardly behind shield plates 48, 51. Mounted on each of the shield plates is a muffle strip 52, 53 of porous sponge arranged either to extend in a continuous strip across the working width of the shield or in individual sections located in alignment with the respective nozzles 45, 46. The positioning of the sponge elements 52, 53 is such that, when the nozzle banks are retracted to the broken line positions shown in Figs. 5 and 6, by rotation of the manifold pipes 43, 44, the nozzle tips depress the material of the sponge, permitting adjacent areas of the sponge to deform around and embrace the orificearea of the nozzleO Accordingly, as the atomizing nozzles continue to discharge atomized water, the discharge is emitted directly into the sponge muffle strips 52, 53. The atomized water is thus instantly condensed within the sponge, as it issues from the nozzle. Water of course accumulates within the sponge muffle elements 52, 53, but as soon as the sponges are saturated, the water flows from the bottom of the sponge, along the lower flanges of the shields 48 9 51 and into the bottom of the collecting tank 33. When the process is resumed again, after a temporary stoppage, it is merely necessary to tilt the nozzle-mounting manifold pipes 43, 44 back to their normal positions, so that the atomized discharge from the nozzles is directed at the fabric surface. The described muffle arrangement also facilitates initial start up of the line, as the nozzle banks may be activated while in the retracted positions and operated briefly to clear the lines and nozzles to avoid sputtering on the fabric itself.
The system of the invention is advantageous in connection 10 with the finish processing of mechanically compacted fabric, where it is desirable to restore surface characteristics of the fabric after the compressive shrinkage treatment. The process is intended for and is useful to greatest advantage in connection with asymmetrical burnish compacting techniques, such as described herein, although it also has possible application in other finishing treatments in which the fabric surface is temporarily affected (as by crushing, for example).
The invention involves the application to the processed fabric of significant quantities of surface moisture, in an 20 extremely finely divided, uniformly distributed state, free of discrete, large droplets or the like, that might cause water spotting, and in amounts significantly greater than is possible either through steaming operations or through natural moisture regain. The fabric, with its surfaces thus substantially moisturized is then conveyed through a stabilized drying process, during which the surface moisture is driven from the fabric while the fabric is s maintained in a geometrically stable condition, as by being confined between a heated dryer drum and a tensioned conveyor belt. During the drying procedure, the surface-applied moisture on the fabric 30 is vaporized, driven slowly through the confined fabric and then released to the atmosphere. During the relatively extended period in which the fabric is traveling in contact with the heated dryer drum (e.g., 15-25 seconds at typical processing speeds), the .r~
natural fibers of the fabric are fully penetrated with moisture~
The resulting effect is to substantially restore the surface appearance of the fabric, where it has been burnished and/or crushed, without significantly affecting the mechanical pre-shrinking imparted to the fabric in the upstream stage of the process.
One of the important practical features of the new process is the ease with which it may be monitored and controlled in a typical plant operation. Generally, a limiting factor is the capacity of the Palmer-type dryer to drive off moisture applied during the moisturizing stageO Accordingly, for a given nominal linear speed of fabric movement (e.g., 14 meters per minute), the rate of moisture application from the nozzle banks 40, 41 is ini-tially adjusted so that the nozzles apply as much moisture as can be removed by the dryer. Since the moisture application is essentially accomplished on a weight per unit area basis, this preliminary setup of the line is relatively independent of the character of the fabric being processed. In a practical embodi-ment of the processing line of the invention, utilizing a Palmer-type dryer with a drum of about 1.5 meters dia~eter, a properbalance of moisture application to drying capacity was realized with an application rate of about 2.5 ounces per square yard.
Having established an appropriate balance between rate of moisture application and drying capacity, the process may there-after be governed almost exclusively by simply increasing or de-creasing the rate of linear movement of the fabric through the processing line. By speeding up the linear movement of fabric, the amoun~ of moisture application per unit of area is propor-tionately decreased, as is the time spent in the dryer phase.
In general, as long as the fabric emerging from the discharge side of the dryer stage has an appearance of two sidedness or other surface characteristics sought to be eliminated, the operator can adjust the process by gradually reducing the rate of linear , movement of the fabric until its appearance is within specifications.
By thus slowing down the fabric, more moisture per unit of area is applied by the nozzle banks 40, 41, and correspondingly more time is spent on the dryer.
As can be well appreciated, different types of con-struction of the fabric will require individually different treat-ment in terms of required levels of moisture application. Likewise, some fabrics may be compressively preshrunk only to a relatively small degree (e.g., 8-10%) while others may have substantially greater compressive shrinkage, all depending on a great variety of conditions and requirements in the mill. The process of the invention, however, easily accommodates the range of such variables, through the simple control of speeding up or slowing down the linear movement of the fabric through the moisturizing and drying stages. In all cases, the speed of operation of the compacting equipment is subservient to the speed of operation of the moisturizing-drying stages. This is accomplished by sensing the size of the fabric loop 22, between the compactor stage and the moisturizer stage, and appropriately increasing or decreasing the speed of the compactor stage.
; In view of the substantial amounts of moisture applied to the fabric during the moisturizing stage, it is significant to maintain the fabric relaxed and quiescent during moisturizing and to maintain fabric geometry during drying. This is accomplished through the use of misting type spray nozzles for moisture application and a Palmer-type dryer for the drying stage. Because the fabric has been compressively preshrunk longitudinally prior to moisturizing, it is significant to the process that the moisture application be in the form of surface application rather than complete impregnation of the fabric, so that the fabric does not lose its geometric integrity while it is unsupported. After the fabric is engaged by the Palmer-type dryer and is geometrically stabilized, the moisture can fully penetrate the fabric without adversely affecting the mechanical compacting.
The spray chamber arrangement described herein has been found to be advantageous for the purposes intended, enabling significantly high amounts of moisture to be applied to the surface of the fabric, while avoiding condensation and spotting problems, and while simultaneously maintaining the fabric in a properly relaxed and quiescent state. In the illustrated arrangement, the fabric enters the open top chamber in the lower front portion, and is guided upwardly, to exit from the chamber in the upper rear portion thereof. The upwardly inclined path of travel through the spray chamber enables the nozzle banks to be conveniently and effectively located both with reference to spray application effectiveness and with respect to avoidance of condensation and drip problems. At the same time, the upwardly inclined path of travel of the fabric is advantageous from the standpoint of minimizing stress on the fabric which, when it emerges from the moisturizing zone, is both moist on its surface and laden with the weight of the moisture, so as to be particularly vulnerable to longitudinal strains. To this end, in addition, the moisturizing chamber is closely coupled with the Palmer-type dryer. Indeed, the exit guide roller for the moisturizing chamber is the entry belt guide roller to the Palmer-type dryer, so that the fabric is physically supported immediately upon its emergence from the moisturizing zone.
The process of the invention is applicable to a wide variety of fabrics, of both knitted and non-knitted constructions and of both tubular and non-tubular configuration, provided the fabric has sufficient natural or other hydrophilic fiber content to enable it to respond to the application of moisture. The process is, of course, extremely advantageous in connection with the finish processing of tubular knitted fabrics, where a relatively high percentage of burnish compacting may be applied to the fabric in a first phase of its finish processing and where uniformity of surface appearance on the top and bottom of the tubular knittedfabric web is of particular significance, inasmuch as the top and bottom constitute the same surface.
In general, the production capacity of available burnish compacting equipment is significantly greater than the linear output capacity of a Palmer-type dryer of practical size and configuration. Accordingly, overall production efficiencies may be improved in many instances by performing the burnish compacting operations separately, rather than in line with the drying operation. In such cases, the compacted fabric may be folded or otherwise gathered in a tension free condition at the discharge end of the compacting equipment. In a separate operation, two or more webs of compacted fabric may be conveyed simultaneously through a common apparatus, to carry out the moisturizing and drying sequence as described herein. Such an arrangement may be particularly advantageous where the compacted web is relatively narrow and/or where the moisturizing-drying treatment of the fabric requires a relatively low linear rate of travel through the dryer for optimum conditioning.
Thus, the invention includes a process for the finish treatment of fabrics containing at least some proportion of hydrophilic fibers, which comprises mechanically compressively shrinking the fabric longitudinally by an asymmetrical compressive shrinkage process, supplying the compressively shrunk fabric to a moisturizing zone and advancing the fabric through said zone, the improvement characterized by applying surface moisture to the fabric, during its passage through said zone, in amounts greater than the potential natural moisture regain of the fabric, and immediately thereafter directing said fabric through a drying zone and drying the fabric while maintaining the fabric geometrically stabilized.
The invention also includes apparatus for carrying out the process of claim 1, which comprises a burnish compactor, s moisturizing means forming a moisturizing zone for the application of finely divided mist to the surface of the fabric, means for guiding and advancing said fabric through the moisturizing means substantially free of lengthwise tension, a Palmer-type dryer arranged in close coupled relation to said moisturizing means, said dryer including a heated drum and a continuous conveyor belt, the improvPment characterized by said moisturizing means including a bank of finely atomizing moisture-emitting nozzles mounted in said chamber; means for controllably disabling said nozzles com-prizing a muffle shield and means for bringing said muffle shieldand said nozzles into positions in which said nozzles discharge directly into said muffle shield; and said conveyor belt being : arranged to engage and support the moistened fabric upon its dis-charge from said moisturizing means.
Claims (19)
1. A process for the finish treatment of knitted fabrics containing at least some proportion of hydrophilic fibers, which comprises (a) mechanically compressively shrinking the fabric longitudinally by an asymmetrical compressive shrinkage process whereby opposite sides of the fabric differ in appearance, (b) supplying the compressively shrunk fabric to a moisturizing zone and advancing the fabric through said zone, (c) applying moisture in the form of a finely-divided mist to the fabric from opposite sides thereof, during its passage through said zone, at a rate which will add substantially more moisture by weight to the fabric than the potential moisture regain in time for the fabric, and (d) immediately thereafter supporting and confining said fabric in a heating and drying zone, to effect drying of the fabric while maintaining the fabric geometrically stabilized whereby significantly improved fabric surface characteristics are achieved through minimization of the two-sidedness in appearance.
2. The process of claim 1, further characterized by said fabric being a tubular knitted fabric.
3. The process of claim 1, further characterized by (a) surface moisture being applied to said fabric from opposite sides thereof, (b) said surface moisturizing being applied in the form of an extremely finely atomized mist directed toward the fabric as it advances through said moisturizing zone.
4. The process of claim 1, further characterized by (a) said surface moisturizing being applied at a constant rate per unit of time, and (b) the amount of surface moisture applied to the fabric being controlled by varying the speed of advance of the fabric through the moisturizing zone.
5. The process of claim 4, further characterized by said fabric being advanced through said drying zone and said moisturizing zone at the same variable speed.
6. The process of claim 1, further characterized by said supplying step being carried out by advancing said fabric in a relaxed and quiescent state through a moisturizing zone.
7. The process of claim 6, further characterized by (a) said surface moisture applied to said fabric on both surfaces with a finely divided mist, and (b) said fabric being guided in a tension free condition through a generally upwardly inclined course through said moisturizing zone.
8. The process of claim 7, further characterized by (a) said fabric being conveyed at the same speed through said moisturizing and drying zones, (b) said mist being sprayed at a constant rate, and (c) the speed of travel of said fabric being controllably adjusted to control the amount of moisture applied to the fabric.
9. The process of claim 1, further characterized by said drying being carried out by confining the moisturized fabric tightly against a moving heated surface.
10. The process of claim 9, further characterized by the period of confinement of said fabric during said drying stage being controllable and variable in direct proportion to the amount of moisture applied to said fabric.
11. The process of claim 10, further characterized by the amount of moisture applied to said fabric being controllably variable by (i) fixing the rate per unit of time of application of moisture and (ii) varying the speed of travel of said fabric.
12. The process of claim 1, further characterized by (a) controllably adjusting the speed of travel of the fabric during moisturizing and drying phases, whereby to control the amount of moisture application per unit of fabric area, and (b) controlling the speed of travel of the fabric through the compressive shrinkage phase, whereby to deliver fabric free of tension to the moisturizing phase.
13. The process of claim 12, further characterized by (a) manually controlling the speed of advance of the fabric through the moisturizing and drying phases in accordance with the observed condition of the fabric, and (b) automatically controlling the speed of advance of the fabric through the compressive shrinkage stage in accordance with the condition of a fabric loop between the compressive shrinkage stage and moisturizing stage.
14. An apparatus for carrying out the process of claim 1, which comprises (a) a burnish compactor, (b) moisturizing means forming a moisturizing zone closely coupled to the burnish com-pactor on the downstream side of the burnish compactor, (c) means within said moisturizing zone for applying a finely-divided mist to the surface of the fabric, (d) means for guiding and advancing said fabric through the moisturizing means substantially free of lengthwise tension, (e) a dryer arranged in close coupled relation to said moisturizing means on the downstream side of said moisturizing means, (f) said dryer including a heated drum and a continuous conveyor belt.
15. Apparatus according to claim 14, further characterized by (a) means for effectively simultaneously variably controlling the speed of operation of said moisturizing means and said dryer, and (b) means for applying moisture to said fabric at a substantially uniform rate per unit of time.
16. The apparatus of claim 14, further characterized by (a) said moisturizing means including a bank of finely atomizing, moisture-emitting nozzles, (b) means for controllably disabling said nozzles comprising a muffle shield and means for bringing said muffle shield and said nozzles into positions in which said nozzles discharge directly into said muffle shield.
17. The apparatus of claim 14, further characterized by (a) means for guiding said fabric in a generally upwardly inclined course through said moisturizing zone, and (b) upper and lower banks of spray nozzles positioned respectively above and below said inclined course and operative to direct sprays of finely atomized moisture toward the upper and lower surfaces respectively of said fabric.
18. The apparatus of claim 17, further characterized by (a) said moisturizing zone comprising an open top vessel, (b) said means for guiding being operable to introduce the fabric in and through the lower front wall of the chamber and to remove the fabric adjacent the upper edge of the rear wall, (c) said conveyor belt being arranged to engage and support the moistened fabric upon its discharge from said moisturizing means.
19. The apparatus of claim 16, further characterized by (a) said muffle shield comprising a soft, spong-like material, and (b) said nozzles being tiltably mounted for movement of the nozzles into contact with said sponge-like material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US84372577A | 1977-10-19 | 1977-10-19 | |
| US843,725 | 1977-10-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1112005A true CA1112005A (en) | 1981-11-10 |
Family
ID=25290848
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA300,339A Expired CA1112005A (en) | 1977-10-19 | 1978-04-03 | Method and apparatus for moisture conditioning of compressively treated fabric |
Country Status (11)
| Country | Link |
|---|---|
| JP (2) | JPS5459484A (en) |
| AU (1) | AU522469B2 (en) |
| BE (1) | BE867580A (en) |
| CA (1) | CA1112005A (en) |
| CH (1) | CH618056GA3 (en) |
| DE (1) | DE2820914C3 (en) |
| FR (1) | FR2406688A1 (en) |
| GB (1) | GB1597743A (en) |
| IL (1) | IL54529A0 (en) |
| IT (1) | IT1109598B (en) |
| NL (1) | NL175444C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1227244B (en) * | 1987-10-12 | 1991-03-27 | Monforts Gmbh & Co A | FINISHING AND WITHDRAWAL SYSTEM. |
| CN103469513B (en) * | 2013-09-11 | 2015-07-15 | 浙江省黄岩服装机械厂 | Electrothermal steam drying and setting machine |
| CN112048852B (en) * | 2020-09-03 | 2024-05-14 | 台嘉成都玻纤有限公司 | Humidification method for glass fiber cloth inspection |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1252617B (en) * | 1958-01-08 | |||
| SE7414499L (en) * | 1973-12-14 | 1975-06-16 | Morrison Machine Co |
-
1978
- 1978-04-03 CA CA300,339A patent/CA1112005A/en not_active Expired
- 1978-04-12 AU AU35031/78A patent/AU522469B2/en not_active Expired
- 1978-04-14 GB GB14855/78A patent/GB1597743A/en not_active Expired
- 1978-04-18 IL IL54529A patent/IL54529A0/en not_active IP Right Cessation
- 1978-04-28 NL NLAANVRAGE7804583,A patent/NL175444C/en not_active IP Right Cessation
- 1978-05-12 DE DE2820914A patent/DE2820914C3/en not_active Expired
- 1978-05-25 JP JP6176478A patent/JPS5459484A/en active Granted
- 1978-05-29 BE BE188123A patent/BE867580A/en not_active IP Right Cessation
- 1978-05-29 FR FR7815955A patent/FR2406688A1/en active Granted
- 1978-05-30 CH CH592278A patent/CH618056GA3/en unknown
- 1978-06-09 IT IT68347/78A patent/IT1109598B/en active
-
1981
- 1981-05-29 JP JP56081219A patent/JPS6014144B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2406688A1 (en) | 1979-05-18 |
| JPS6014144B2 (en) | 1985-04-11 |
| IL54529A0 (en) | 1978-07-31 |
| BE867580A (en) | 1978-09-18 |
| IT7868347A0 (en) | 1978-06-09 |
| FR2406688B1 (en) | 1981-12-31 |
| DE2820914C3 (en) | 1980-09-18 |
| AU522469B2 (en) | 1982-06-10 |
| CH618056GA3 (en) | 1980-07-15 |
| JPS5459484A (en) | 1979-05-14 |
| JPS5777370A (en) | 1982-05-14 |
| AU3503178A (en) | 1979-10-18 |
| IT1109598B (en) | 1985-12-23 |
| CH618056B (en) | |
| NL7804583A (en) | 1979-04-23 |
| DE2820914B2 (en) | 1979-11-22 |
| GB1597743A (en) | 1981-09-09 |
| NL175444C (en) | 1984-11-01 |
| DE2820914A1 (en) | 1979-04-26 |
| NL175444B (en) | 1984-06-01 |
| JPS6224542B2 (en) | 1987-05-28 |
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| MKEX | Expiry | ||
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