HK1148324A - Apparatus for dyeing textile fabrics and yarns with foamed dye - Google Patents

Description

Apparatus for dyeing textile fabrics and yarns with foam dyes

This application was filed on 31/1/2008 and was filed on 7/8/2008 as a continuation-in-part of pending U.S. patent application No.12/012,077, published under publication No. 2008-0184747-a 1; pending U.S. patent application No.12/012,077 is again filed on 25/5/2007 and is filed on 22/11/2007 as part of pending U.S. patent application No.11/805,893, published under publication No. 2007-0266505-a 1; pending U.S. patent application No.11/805,893 is a continuation-in-part of U.S. patent application No.10/833,450, filed on 28/4/2004, published on 3/11/2005 under publication No. 2005-0241078-a1 and now abandoned.

Background

The present invention relates to an apparatus for dyeing textile fabrics and yarns with a foam dye, wherein the foam dye is applied incrementally by a plurality of spaced apart applicators. In one form, the invention relates to an apparatus for dyeing a textile substrate comprising cellulosic fibers with a reduced leuco-state dye, wherein the leuco-state dye is foamed with an inert gas and applied to the textile substrate in a colorless foamed state in an inert atmosphere and subsequently oxidized on the textile substrate so as to adhere the indigo dye to the cellulosic fibers of the textile substrate.

There is a great market for dyeing cellulosic textile materials (e.g., cotton yarns or fabrics) with leuco-state dyes (e.g., indigo dyes), especially cotton denim garments, such as jeans. The fastness of indigo dyes on cotton and the deep colour or shade that can be obtained make indigo dyed fabrics very popular products. Dyeing cellulosic textile materials with indigo dye, however, is a complex, complex and expensive process, since indigo dye does not adhere to the cellulose fibers in its natural state. In order to color indigo dye that can adhere to cellulose fibers, it is necessary to reduce the indigo by removing oxygen, as by mixing with hydrosulfate (or hydrosilate) or other reducing agents to color the indigo into a colorless, colorless material. The indigo dye must therefore be treated to remain substantially in the leuco-state until it is applied to the cellulosic textile material. To be able to be applied, the leuco-state indigo dye must be sufficiently diluted to penetrate into the interstices of the cellulosic material. Typically, indigo dye is obtained from a supplier in the form of a paste, i.e. in e.g. a 40% solution. Thus, the indigo dye must be further diluted with a non-oxidizing liquid (e.g., hyposulfite and sodium hydroxide) to, for example, a 2% solution in order to maintain a colorless state that can penetrate into the advancing textile substrate, which is submerged and passed through a vat of diluted indigo dye. Due to this dilution, it is necessary to pass the textile substrate through a series of successive indigo dye vats and to fix the indigo applied during the previous immersion with intermediate exposure to the atmosphere or other oxidizing agent. In order to obtain the desired dark colour or shade, it is common to use a dyeing unit (dying range) having four to eight dye vats, arranged in sequence with an arrangement of guide rolls between them to ensure that the indigo is properly oxidised between the dye vats. In addition, the dye in the vat must be continuously and rapidly recirculated in one or more tanks to which reduced water or other similar material is added or regulated in order to remove oxygen taken up in the dye vat and restore any oxidized indigo dye to a reduced leuco-state.

One notable problem with prior art indigo dyeing units is the disposal of waste dye and water. Since it is necessary to provide a large number of vats and a large amount of dye liquor, a large amount of dye liquor must be treated at the end of each dyeing operation. This creates an undesirably large amount of overhead and environmental problems.

One prior art staining system is disclosed in U.S. patent No.4,613,335 issued to Hans-Ulrich Berendt et al at 23.9.1986. This patent discloses a process for dyeing or printing cellulose-containing textile materials in which a vat leuco-state dye in a foam carrier is used. Although dyeing is mentioned, the disclosure is primarily directed to printing, and there is no disclosure therein of placing the substrate in a sealed inert atmosphere. In contrast, the substrate is exposed to the atmosphere as it approaches, passes through, and exits the applicator. Thus, there is no control of the condition of the substrate as it approaches and passes under the applicator, and there is no control of the oxidation of the dye after it is applied to the substrate.

In contrast, the present invention provides in one form a substrate and applicator face in a controlled inert atmosphere, thereby enabling the application of a foam in the absence or controlled oxidation of the leuco-state dye, and the foam is at least partially broken in the inert atmosphere, thereby allowing the dye in the leuco-state to spread on the substrate without oxidation or with only controlled limited oxidation, and then the dye is sufficiently oxidized as the substrate leaves the inert atmosphere and when the substrate is exposed to the atmosphere, thereby ensuring that the desired adhesion of the dye on the substrate occurs.

In another form of the invention, the apparatus is not limited to dyeing any particular textile fabric substrate, wherein the dye may be in the leuco-state or may be in any other form that is foamed for application to a traveling substrate. Furthermore, the apparatus is not limited to a staining chamber sealed from ambient air, but can be used with both sealed and open chambers. This version of the apparatus utilizes a plurality of spaced foam applicators that apply dye in foam form incrementally to the surface of the substrate, and which are also spaced apart to allow the foam to at least partially collapse between the applicators. The dye application of the bulk market is particularly advantageous for dyeing denim fabrics or pieces of cellulose yarn to be used for weaving denim fabrics, because multiple applications of the dye result in a deeper and denser shade on the substrate, and the application of the dye in the form of a foam greatly reduces the moisture content of the dye, thereby significantly reducing the time required to dry the substrate after application of the dye as compared to substrates coming out of the dyeing bath.

To reduce the footprint of the apparatus and to facilitate access for maintenance of the components of the apparatus, the apparatus may include a movable side that can be opened, wherein a roller or applicator may be moved with the side to allow access to the interior of the apparatus for cleaning and maintenance. In a horizontal arrangement of the components of the apparatus, the apparatus may have a hood which can be opened to allow access, but this exposes the technician to the risk of: the cover may fall on the body of a technician who is working on the components inside the device and it also makes it difficult to see from the underside, so the aforementioned open form is advantageous compared to the aforementioned horizontal arrangement of the components of the device.

In the manufacture of certain woven products (particularly dyed denim), it is advantageous to be able to dye the yarn before it is woven into a fabric, but it is difficult to control the yarn and keep it from tangling or flipping when applying the foam in the form of a dye rather than passing the yarn through a bath. In one form of the invention, the apparatus is particularly suited for dyeing a piece of yarn by controlling the piece of yarn with spaced pinch roll pairs and with a foam applicator disposed between the spaced pinch roll pairs. In this arrangement, the applicators are preferably arranged in pairs so as to apply foam to opposite sides of the running yarn sheet. The combination of multiple pinch roll pairs, with which the tension of the yarn sheet feed can be controlled, and multiple roll pairs and pairs of applicators to incrementally apply dye, resulting in a highly colored and substantially undyed core on the surface, is particularly desirable to provide a popular effect after the fabrics woven from these yarns are sanded or otherwise treated.

Disclosure of Invention

Briefly, in one form of the present invention, an apparatus for dyeing a textile substrate containing cellulosic fibers with a foamed reduced leuco-state dye is provided. The apparatus includes a housing having an interior chamber sealed from atmospheric air through which the substrate travels from an inlet having a seal and through which the substrate enters the chamber to an outlet also having a seal through which the substrate exits the chamber. An inert gas source is in communication with the chamber to provide an inert environment within the chamber. At least one foam applicator has an applicator face within the chamber and extending across the width of the substrate for applying a foam containing a leuco-state dye to the substrate within the chamber. A foam generator generates foam containing the leuco-state dye in the absence of oxygen, wherein the generator is in communication with the applicator for supplying the foamed leuco-state dye to the applicator. Thus, oxidation occurs primarily only after the substrate exits the chamber. However, a minimum amount of oxygen may be present in the inert gas, and some small, controlled amount of oxygen may also be purposefully contained in the inert gas for the desired controlled partial oxidation of the dye before it exits the chamber. Preferably, the supply of inert gas is under pressure to provide a pressurized inert environment within the chamber and to minimize the ingress of atmospheric air through the inlet and outlet. Further, preferably, the at least one applicator is spaced from the inlet to provide a free release area (free reach) of the substrate in which air trapped in the interstices of the substrate is allowed to escape, and the at least one applicator is also spaced from the outlet to allow the foam on the substrate to collapse before the substrate exits the chamber and the dye is oxidized to deposit and distribute the leuco-state dye on the substrate.

In a preferred embodiment of this form of the invention there are a plurality of applicators having application faces within the chamber and provided with spaces between the applicators to allow the foam to at least partially collapse and to allow the leuco-state dye to at least partially deposit on the substrate before the foam is applied by a subsequent applicator. A compression element, which may be in the form of a roller, may be disposed between the applicators for engaging the substrate to displace the substrate between the applicators to maintain foam receiving engagement between the substrate and the applicator face. These applicators are preferably parabolic in shape for uniform distribution of foam across the width of the substrate.

In the preferred embodiment, the inert gas is nitrogen and the foam generator generates a nitrogen foam containing the leuco-state dye. One advantage of nitrogen in the foam is that when the foam collapses within the chamber, the nitrogen increases the amount of inert nitrogen in the chamber environment.

This form of the invention has particular application in order to dye woven denim fabric with indigo dye which may be applied in an amount of about 5% to 20% (preferably 10% to 15%) by weight of the fabric.

To allow access to the room, the housing may have an openable cover sealingly mounted thereon, and the holddown elements may be mounted on the movable frame so as to move the holddown elements away from the spaces between the applicators when the cover is opened.

In another form of the invention, the apparatus is used to dye a traveling textile fabric substrate within a housing having an interior chamber through which the substrate travels. An entry roller assembly feeds the substrate into the chamber and an exit roller assembly pulls the substrate out of the chamber. A plurality of spaced foam applicators are disposed within the chamber and have applicator faces extending transversely of the advancing substrate for incrementally applying dye in foam form to the surface of the substrate, the spacing between the applicators allowing the foam to at least partially collapse between the applicators to facilitate dye application by a subsequent applicator. In order to maintain the traveling substrate in contact with the foam conveying surface of the applicators, a pressing element, which may be in the form of a roller, extends between the applicators below the level of the applicator surface. The holddown elements are preferably idler rollers and minimize the increase in tension in the traveling substrate as the substrate travels over successive applicators, the depth of the holddown elements between the applicators gradually decreasing in the direction of substrate travel to reduce the angle of inclination and thereby reduce the tension causing friction. This reduction in depth is obtained by providing a housing with a cover to which the hold-down elements are attached and having spacer blocks between the hold-down elements and the cover, the number of spacer blocks decreasing with successive hold-down elements in the direction of travel of the substrate. The chamber may be sealed from the atmosphere in the manner previously described for the present invention, or the chamber may be open to the atmosphere when dyed with a non-leuco-state dye. The entry roller assembly and exit roller assembly are driven synchronously to maintain substantially uniform tension in the substrate as it travels through the apparatus, thereby facilitating uniform incremental foam application. A first holddown element or roller is mounted before the first applicator and a last holddown element or roller is mounted after the last applicator, wherein the first and last holddown elements guide the substrate at the same level as the entry and exit roller assemblies.

In both of the above forms of the invention, the pressing element between the applicators is preferably an idler roller or an inverted applicator, wherein the face of the inverted applicator engages and presses against the top face of the applicator. In the case of an inverted applicator, a dye foam is applied to the top surface of the substrate, which may or may not be the same color as the dye applied by the underlying applicator, either the same dye or a different dye. In addition, whether only the lower applicator is used, or both the lower and upper applicators are used, different applicators may be used in the same apparatus to apply different colors and/or different dyes, whether with an inert atmosphere or with ambient air.

To reduce the footprint of the apparatus and facilitate access for cleaning and maintenance of the components of the apparatus, the components may be arranged in an upright arrangement with the spacing of the applicators and the spacing of the holddown elements in a vertical sequence so that the substrate travels downwardly through the apparatus rather than horizontally. This arrangement also allows for horizontal separation of the opposing components, facilitating access for cleaning and maintenance.

In another preferred form of the invention, the apparatus is arranged for dyeing a travelling textile substrate, in particular a sheet of travelling textile yarns. In this form, the apparatus includes a housing having an interior chamber through which the substrate or yarn sheet travels from the entry roller assembly and through the housing to an exit roller assembly disposed below the entry roller assembly for vertical movement of the substrate or yarn sheet through the housing. A plurality of vertically spaced pairs of rollers, at least one of which is driven, form a nip for feeding a substrate or yarn sheet through the housing. At least one foam applicator, preferably an opposed pair of applicators, is disposed between adjacent pairs of rollers and extends transversely across the traveling substrate or sheet of yarn for incrementally applying dye in foam form to the surface of the substrate or sheet of yarn. The drive control means controls the coordinated driving of the pairs of rollers so as to maintain tension in the substrate or yarn sheet as it passes through the apparatus. With pairs of opposing foam applicators, the applicators in each pair are vertically spaced and horizontally overlapped so as to oppositely deflect the substrate or sheet of yarn across the foam dispensing face of the applicator to maintain proper contact for foam application. In order to minimise the increase in tension in the yarn in the substrate or sheet as it travels across successive applicator faces through the apparatus, the amount of overlap of the applicator faces may be arranged to decrease with successive pairs of rollers in the direction of travel.

When dyed cellulosic fibers (e.g., yarns) are woven into denim fabrics, the dye is typically an indigo dye in the leuco-state, which must remain substantially oxygen-free during application. To this end, the housing of the apparatus is formed with an internal chamber sealed from the atmosphere for containing the inert environment, and the inlet and outlet are formed with seals that provide substantial protection against the ingress of atmospheric air into the chamber.

In order to provide a substantially uniform foam distribution over the entire width of the applicator without uneven decomposition, the applicator is preferably parabolic in shape and preferably has a plurality of parabolic shapes aligned over its lateral extent.

If desired, a foam applicator or a pair of foam applicators may be provided between the entry roll assembly and the pinch roll pair.

With the preferred embodiment described above, the yarn sheet can be dyed in incremental applications, wherein the yarn sheet is controlled during passage through the apparatus.

Drawings

FIG. 1 is a side view of a dyeing unit incorporating apparatus according to one form of the preferred embodiment of the present invention;

FIG. 2 is a plan view of the dyeing unit of FIG. 1;

FIG. 3 is an end view of the inlet end of the dyeing apparatus included in the dyeing unit of FIGS. 1 and 2;

FIG. 4 is a plan view of the apparatus of FIG. 3 with a portion of the cover removed;

FIG. 5 is a side view of the apparatus of FIG. 3;

FIG. 6 is a side view of the apparatus of FIG. 3 with a side panel removed;

FIG. 7 is similar to FIG. 6, with the housing and roller frame both open;

FIG. 8 is a view similar to FIG. 6 showing an alternative outlet seal and drain;

FIG. 9 is a view similar to FIG. 6, with the apparatus modified to have a plurality of compacting elements in the form of inverted applicators;

FIG. 10 is an apparatus of another form of the preferred embodiment of the dyeing apparatus of the present invention, in which the side panels are removed;

FIG. 11 is an end view of the apparatus of FIG. 10;

FIG. 12 is a side view of the entry roller assembly of the apparatus of FIG. 10;

FIG. 13 is a side view of an exit roller assembly of the apparatus of FIG. 10;

FIG. 14 is an enlarged view of one of the applicators of the apparatus of FIG. 10;

figures 15, 16 and 17 illustrate operation of the closure of the apparatus of figure 10 from a closed position (figure 15), to an initially vertically raised position (figure 16), to a pivoted open position (figure 17);

FIG. 18 is a plan view of the cover of the apparatus of FIG. 10;

FIG. 19 is a side view of the embodiment of the previous figures, wherein the components are arranged vertically rather than horizontally;

FIG. 20 is a view similar to FIG. 19, but showing the components separated for access for repair and maintenance;

FIG. 21 is a perspective view of an additional embodiment of the present invention;

FIG. 22 is a side view of the embodiment of FIG. 21;

FIG. 23 is a view similar to FIG. 22 showing the drive control components;

FIG. 24 is a front view of the apparatus of FIG. 21 with the take-up drum (take up drum) removed;

FIG. 25 is a perspective view of the apparatus of FIG. 21;

FIG. 26 is a vertical cross-sectional view of one of the inlet and outlet seals of the apparatus of FIG. 21;

FIG. 27 is a side view of the apparatus of FIG. 21 showing a modification of the apparatus for separating components for repair and maintenance; and

FIG. 28 is a plan view of an applicator showing a multiple parabolic shaped dispensing system for an applicator of the type used in the apparatus of FIG. 21;

Detailed Description

A form of the dyeing apparatus 10 in a preferred embodiment of the invention is illustrated in fig. 1-8, where fig. 1 and 2 show the apparatus incorporated in a dyeing unit 12. The sheets of textile substrate S are fed to the set 12 from a supply roll 14 or from a source of folded material in a supply box 16. Then, the substrate S is loosened in the J-box 18, drawn out of the J-box 18 by the feed roller assembly 20, travels under the crosswalk-type lattice 48, and the observer O stands on the crosswalk-type lattice 48 to monitor the dyeing operation in the dyeing apparatus 10. The substrate is pulled through the dyeing apparatus 10 by a driven pull roll assembly 22. The drive of the feed roller assembly 20 and pull roller assembly 22 is controlled so that the substrate S maintains a desired tension in the substrate S as it travels through the apparatus 10. At the auxiliary dye application station 24, the substrate from the pull roll assembly 22 may undergo an auxiliary treatment in which a foam applicator 26 applies a surface treatment, for example, the same or different dye as applied in the dyeing apparatus 10, or any other desired surface treatment material that can be applied to both sides of the substrate. The treated substrate is then passed through an infrared dryer 28 to reduce the moisture content to a desired level. Alternatively, any other type of dryer may be used. From the dryer 28, the substrate S passes under a crosswalk grid 50, across a series of guide rollers 30, and then onto a driven take-up roller 32 to form a roll 34 of dyed substrate S.

As schematically shown in fig. 2, inert gas is fed to the dyeing apparatus 10 from a source 36, the source 36 may be a supply tank containing inert gas, or an inert gas generator, such as a nitrogen generator. The gas is fed to the interior of the apparatus 10 through the supply line 40 to provide an inert environment.

The inert gas is also fed from a source through a second supply line 38 to a foam generator 42, the foam generator 42 also receiving reduced leuco-state dye from a dye supply tank 44. When dye is fed from the dye supply tank 44 to the foam generator 42, the dye supply tank 44 is maintained in a sealed condition, preventing air from entering the supply tank 44, so as to prevent oxidation of the leuco-state dye. The foam generator is any conventional type of foam generator capable of generating foam using nitrogen gas and distributing dye in the foam, which is then fed into the dyeing apparatus 10 through feed line 46.

The dyeing apparatus 10 is shown in detail in figures 3 to 8. The leading roller 52 guides the substrate S from the horizontal direction to the vertical direction, wherein the substrate travels under the leading roller 52. The leading roller 52 is mounted on a housing 54 of the dyeing apparatus 10.

As the substrate S travels vertically from the leading roller 52, the edge E of the substrate S passes over a pair of opposed sensing forks 56 (shown in fig. 3 and 4), which sense the position of the edge E. The servo motor 58 adjusts the end seal 60 in response to sensing the position of the edge E of the substrate S so as to limit the application of foam to the lateral extent of the substrate without allowing significant foam from the applicator to escape the position of the lateral edge E of the substrate S.

The housing 54 is formed by opposing side plates 64 and corner support legs 66. The upper portion of the housing 54 is formed as a chamber 68, the chamber 68 being formed by: a front wall 70 and a rear wall 71; side plates 64 of the housing; a bottom plate 72; an L-shaped wall 73 extending from the floor 72 to the inlet and outlet seals 92, 126; and a pivotable cover 74 sealingly placed over the upper edges of the walls 70 and panel 64 with a sealing material (e.g., a resiliently compressible foam material), or the seal may be provided by forming a channel containing water at the top of the walls 70 and panel 64, with the bottom edge 76 of the cover being placed in the water in the channel (not shown). The hood 74 is opened and closed by a pair of laterally spaced piston-cylinder mechanisms 78, the piston-cylinder mechanisms 78 having an end 80 attached to the center of the hood 74 and another end 78 attached to an upstanding support post 84, the support post 84 extending upwardly from the top of the housing 54. To accommodate this pivoting of the hood 74, the hood 74 is mounted on a pivot shaft 86, and a support rod 88 is also mounted on the pivot shaft 86, the support rod 88 being adjacent to the piston-cylinder mechanism 78 and centered on the hood 74. These support rods 88 stabilize the hood 74 during pivoting.

The hood 74 is formed with an observation window 90 through which an observer O can monitor the operation of the dyeing apparatus 10 while the substrate S travels through the dyeing apparatus 10. An inlet seal 92 is located at the front of the chamber 68 and the substrate S enters the chamber 68 through the inlet seal 92. The inlet seal 92 is formed by two pairs of spaced inflatable bladders 93, the bladders 93 preventing air from entering the inert environment in the chamber 68. Above the entrance seal 92, an entrance guide roller 94 guides the substrate S to a plurality of longitudinally spaced foam applicators 96, 98, 100, 102 and 104. Guide rollers 94 are located below the level of the face 106 of the first foam applicator 96 to ensure positive effective engagement of the substrate S and the applicator face 106.

The applicators 96, 98, 100, 102 and 104 are mounted on the base plate 72 by securing the flanges 103 on these applicators to the base plate 72.

A pinch roller mounted on a frame 108 is mounted above the foam applicator 96. The frame 108 has four pinch rollers 110, 112, 114 and 116 mounted on its underside. The pinch rollers 110, 112, 114 and 116 are disposed between the foam applicators and project downwardly below the level of the faces of the applicators, forcing the substrate S to deflect downwardly between the applicators to ensure positive engagement of the substrate S with the faces 106 of the applicators.

The frame 108 carrying the pinch rollers 110, 112, 114 and 116 is pivotable on a pivot axis 178, the pivot axis 178 being spaced above and behind the last applicator 104. The frame is held in the operative position by wing nuts 180 attachable to the upright brackets 122, with the upright brackets 122 being located forward of the first foam applicator 96. Coil spring 121, which is secured to rear wall 71 of chamber 68, and rearward extension 140 of frame 108 bias frame 108 toward the open position such that frame 108 will pivot upward to the open position when wing nut 180 is released.

Beyond the last foam applicator 104, exit guide rollers 124 are mounted below the level of the foam applicator for guiding the substrate S away from the foam applicator and down through exit seals 126, the exit seals 126 having pairs of spaced-apart inflatable sealed cells (where the exit seals 126 and cells 128 and the inlet seals 92 and cells 93 are identical) so as to prevent atmospheric air from entering the chamber 68.

Guide rollers 130 are spaced below the exit seal 126, which direct the substrate vertically downward and then horizontally outward to the pull roll assembly 22.

Both the inlet seal 92 and the inlet guide roller 94 are spaced from the first foam applicator 96 so as to provide a free release area of the traveling substrate from which air that has been trapped in the interstices of the substrate S and thus into the chamber 68 will have a chance to escape, thereby avoiding any undesirable oxidation of the reduced leuco-state dye as it is applied to the substrate.

The foam applicators 96, 98, 100, 102 and 104 are spaced from one another such that as the substrate travels from one foam applicator to the next, the substrate is deflected by intermediate guide rollers 110, 112, 114 and 116 to provide free time between the applicators for breaking the foam and spreading the dye prior to dye application by the next applicator. Similarly, exit guide roller 124 and exit seal 126 are also spaced from the last foam applicator 104 to allow for foam collapse and dispersion of the dye that is exposed to atmospheric oxygen after passing through exit seal 126 before the substrate exits the inert environment within chamber 68.

In the preferred embodiment of fig. 1-8, each of the foam applicators 96, 98, 100, 102 and 104 is a parabolic-shaped applicator of the type disclosed in U.S. patent No.4,655,056 issued to Dieter f.zeiffer on 7.4.1987. This type of applicator is particularly useful because the parabolic shape distributes the foam equally and over equal distances from the input to the full extent of the applicator face. Other applicator types may be used and may bring different results.

The applicator in the auxiliary dye application station 24 may also be parabolic in shape, particularly if the applicator is to apply foam, but any other type of dye or other surface treatment may be applied in the applicator as well as in other types of applicators.

As shown in fig. 6 and 7, a gutter 131 located at each side of the chamber 68 declines centrally outside of the applicators and towards a drain 132, the drain 132 collecting any excess dye or other liquid, and also having a closure 134 which may be opened at the end of the dye stroke to allow flushing of the chamber 68. The closure 134 is also open at the beginning of the time that nitrogen or other inert gas from the inert gas source 36 is fed under pressure into the chamber 68. Since atmospheric air is heavier than nitrogen, the introduction of nitrogen under pressure will result in the atmospheric air being expelled from the closure 134. When all or substantially all of the atmospheric air has been exhausted from the chamber 68, the closure 134 is sealed and the substrate S is threaded through a leader blade or otherwise to begin operation. Alternatively, the substrate may be threaded before the air is evacuated from the chamber 68, but this will result in the substrate being defectively dyed over a small portion of its length.

By spacing the inlet seal 92 and inlet guide roller 94 from the first applicator 96 to provide a purge of oxygen-laden air from the interstices of the fibrous structure, premature oxidation of the dye liquid is prevented, while allowing subsurface liquid migration (which is limited where the dye is oxidized); the dye liquid is prevented from becoming immobilized resulting in loss of control over the distribution of the dye molecules.

However, because commercially available inert gases (e.g., nitrogen) all contain some small amounts of oxygen, and commercial inert gas generators also do not produce a completely pure inert gas, there may be a minimal amount of oxygen in the inert atmosphere, resulting in some inadvertent slight oxidation of the dye on the substrate before the substrate exits the chamber. An advantage of the present invention is that if desired, a small portion of controlled amount of oxygen can be purposefully included in any conventional manner to provide partial oxidation of the dye on the substrate during and/or after dye application and before the substrate exits the chamber, while the dye is fully oxidized in the ambient atmosphere.

If acceptable, only one foam applicator may be incorporated into the apparatus through which all of the foam is supplied, but preferably a plurality of foam applicators are used, each applying a fraction, which may be equally or selectively distributed, depending on preference, to enable deeper shades to be obtained by multiple foam applications with the same amount of dye. In the case of multiple foam applicators, where each applicator feeds a relatively small limited amount of dye-containing foam, dye migration into the surface of the fiber can be a controlled process. A relatively small amount of foam is then placed in an overlapping fashion on the same fiber surface area, which will allow dye enrichment to be achieved. Successive dye applications are completed without oxidizing any dye until the last application is made. The substrate surface fibers do not satisfactorily absorb the large amount of foam applied by one applicator (rather than multiple applicators) because a single application of a large amount of foam will spread the dye to a greater extent into the substrate rather than being concentrated on the surface fibers. Multiple applications allow dyeing with less moisture pick-up, thereby resulting in less drying requirements and less waste water generation.

As the space of the dye liquid delivery system is filled with vat dye, the liquid itself (which may be formulated at low viscosity) applied incrementally to the surface of the fiber will provide a controlled specific rate of impregnation. During foam application, the minimum viscosity of the foam can be maintained, with the foam in a state of only temporary delivery. The foam breaks almost immediately upon contact with the fibers and does not impede the dye impregnation process. An incremental overlap of a small amount of liquid with a time interval or impregnation stage occurs between each subsequent foam application, wherein the dye is in a non-oxidized state, in significant contrast to the prior art.

In this form of the preferred embodiment, the indigo dyeing in the reduced leuco state can be run at normal process speed ranges, for example about 60 meters per minute. A typical fabric weight is 400 grams per square meter and a typical amount of indigo dye to be applied to one side of the fabric may be, for example, about 5% to about 30% of the fabric weight, which dyes may be divided in any fashion between five applicators. For example, for a total of 10%, each applicator may apply 2% of the dye liquid; or each applicator may apply 3% of the dye liquid for a total of 15%; or each applicator may apply unequal amounts of dye liquid; or may be any combination dispensed by different applicators.

FIG. 8 shows a modification to the outlet seal and drain position. In this arrangement, the exit seal 136 is positioned in a horizontal arrangement so that the substrate exits horizontally, and the exit guide rollers 138 are positioned on the frame 108 in a manner similar to the manner in which the guide rollers 110, 112, 114, 116 are mounted on the frame 108 (as in the form of FIGS. 1-7), so that the substrate is deflected downward after the last applicator 104 for guidance to the horizontal exit seal 136.

In this variation, drain 142 is located at the rear of housing 54, and sump 141 is inclined downwardly and rearwardly to drain liquid from chamber 146 into sump 141 and drain 142 for draining from drain 142 when drain closure 148 is open.

Variables such as liquid flow, substrate speed, chemical formulation, nitrogen purity, fabric preparation, and fiber virgin state can have different impact effects on the color shade obtained. Also, while the substrate is primarily cellulosic for dyeing with leuco-state indigo, the substrate may contain some small amount of synthetic fibers to achieve any desired result. By varying the number of applicators used in liquid application, the variation in hue is easily achieved even with the same total flow rate. For example, it may be found that liquid has penetrated to the back of the fabric substrate when a 15% pick-up level is applied by one applicator, but if the same total amount of 15% pick-up is applied successively by five applicators, respectively, there will be no indication of any liquid on the back of the fabric substrate. As the fabric exits the chamber 68, the reduced leuco-state dye is almost immediately oxidized as it is exposed to ambient air.

An advantageous advantage of the present invention is that when the foam collapses, the nitrogen used to create the foam is released into the environment of chamber 68, thereby increasing the nitrogen content within chamber 68, compensating for any nitrogen escaping from the chamber. This reduces the amount of nitrogen that must be supplied to the chamber 68.

The number of applicators used in the apparatus of the present invention may vary from one to as many as six or more, depending on the desired application flexibility. Also, application of the liquid can be accomplished at ambient temperature, but if desired, high temperatures can be utilized to provide certain benefits to certain fabrics and processes.

Although a device having four applicators is shown and described in the drawings and detailed description, it should be understood that the device can be operated with all or fewer than all applicators (including with only one applicator) to effectively apply foamed dye, and it should also be appreciated that the invention can be practiced with devices made with only one applicator or any desired number of applicators, all of which can be active, or some of which can be idle.

The pressure of the nitrogen gas in chamber 68 need only be slightly above atmospheric pressure. The nitrogen pressure needs to be higher than atmospheric pressure enough to prevent atmospheric air containing oxygen in the environment from entering the chamber 68 causing oxidation of the applied dye.

As shown in fig. 9, an inverted applicator may be used as the pressing element, rather than an idler roller. In this illustration, the apparatus 200 is similar to the apparatus of fig. 6 and 8, wherein the apparatus 200 includes a housing 202, a first guide roller 204, an inlet seal 206, an inlet guide roller 208, a plurality of upwardly facing applicators 210 mounted on a platform 212, followed by an outlet seal 216.

The device 200 has an openable cover 220 similar to the cover in fig. 6 and 8. However, the cover does not include a separate frame. Instead, the shroud 220 has a downwardly biased internal platform 222 on which mounted hold down elements are in the same position as the idler hold down elements in FIGS. 6 and 8 and serve the same purpose as the idler hold down elements in FIGS. 6 and 8. In this variation, the compacting element is an inverted applicator 224, which is identical to the underlying applicator 210, but is inverted. These inverted applicators 224 serve the same compaction purpose as the rollers in fig. 6 and 8, but additionally serve to apply the foamed dye to the top surface of the substrate S as it passes under the applicator face 226 of the inverted applicator 224.

Using these inverted applicators as the compacting element, the same or different dyes as the dye on the lower surface of the substrate can be applied to the upper surface, and a variety of different dyes, including leuco-type dyes as well as standard dyes, can be applied by each applicator, with the device 200 operating with either a sealed inert atmosphere or unsealed ambient atmospheric air contained within the device 200.

Another form of the preferred embodiment of the invention is shown in fig. 10-18. This version includes a dyeing apparatus 300 similar to the apparatus 10 and 200 of the previous version and can be incorporated into a general dyeing train similar to the dyeing train 12 of the previous embodiment. Referring to the assembly as shown in FIG. 2, when the apparatus 300 in the embodiment of FIGS. 10-18 is used with an inert atmosphere in the manner of the apparatus 10 and 200 described above, the apparatus 300 uses a similar inert gas source, foam generator, and dye supply tank. This version of the apparatus 300 of this embodiment may also be used with ambient air, in which case the inert gas source would not be included, but only the foam generator and dye source would be used, with neither the dye source nor the foam generator requiring inert conditions.

The device 300 includes a housing 302 supported on legs 304 and having end walls 306, side walls 308, a floor 310, and a cover 312. These walls 306, 308, 310 and the cover 312 form an interior chamber 314. To use the device 300 for dyeing with leuco-state dyes, as in the previous embodiment, the chamber 314 may be hermetically sealed with the cap 312 on top of the walls in the same manner as the cap 74 is sealed in the previous embodiment.

The advancing textile fabric substrate S is fed to the chamber 314 by an entry roller assembly 316 having three rollers, two 318 of which are vertically spaced and a third 320 of which is offset therebetween. These rollers are driven by a motor 322 (shown in fig. 12). After passing through the entry roller assembly 316, the substrate S travels around a tension sensing roller 324 mounted on a load cell 326, whereby the substrate S travels through an entry end seal 328 into the chamber 314. The substrate exits the chamber 314 through an outlet end seal 330 (which is identical to the inlet end seal 328) at the other end of the chamber 314 and passes through an exit roller assembly 332. the exit roller assembly 332 has an arrangement with two spaced rollers 334 and an offset roller 336 similar to the rollers 318 and 320 in the entry roller assembly 316. A motor similar to and synchronized with the drive motor 322 of the entry roller assembly drives the rollers 334 and 336.

Fig. 13 shows the exit roller assembly 332. As shown in fig. 13, a drive belt 338 travels around offset rollers 336, spaced rollers 334, and two guide pulleys 340. A belt tensioning element 342 is adjustably mounted in contact with the drive belt 338 to maintain the belt in driving tension.

Five foam applicators 344 are mounted within the housing 312 and extend into the chamber 314. The foam applicators 344 extend across the apparatus, spaced apart from and extending parallel to each other for sequential travel of the substrate S over the applicators.

These applicators 344 are similar to the applicators 96-104 described and illustrated above with respect to the embodiment of FIGS. 1-8 and the applicator 210 of FIG. 9, and are as disclosed in U.S. Pat. No.4,655,056 issued on 7.4.4.1987 to Dieter F. As seen in the enlarged view in fig. 14, each applicator 344 has an L-shaped conduit 346 through which a foaming dye is supplied from a foam source. An L-shaped conduit 346 leads into the top of the parabolic applicator 344 and is displaced therein to a slot 348 in the applicator face 350 over which the substrate travels and receives foam from the applicator. The applicator face 350 is domed to allow the substrate S to cover the groove 348 without appreciable leakage of foam from the groove 348.

At the bottom of the parabolic applicator 344, a pneumatically operable ball valve 352 is operated to allow for discharge of the applicator at the end of the application, or to otherwise purge or empty the applicator into a discharge manifold 354.

The substrate is held down against the applicator face 350 to ensure proper foam application to the substrate surface without significant leakage. This is accomplished by four pinch rollers 356, each located between two applicators 344, with a first pinch roller 358 before the first applicator and a last pinch roller 360 following the last applicator. Each of the intermediate, first and last pinch rollers 356, 358 and 360 extends downwardly below the level of the applicator face 350 to advance the engaged substrate S upwardly to the applicator face 350 and downwardly from the applicator face 350. The first pinch roller 358 engages the substrate at the level of entry of the substrate through the entrance end seal 388, while the last pinch roller 360 positions the substrate to travel away from the exit end seal 330 at the level of the exit end seal 330.

To avoid the complexity of the drive mechanism and the necessity of sealing off the external drive or power source, particularly when sealing the interior chamber 314 from ambient air, the pressure rollers 356, 358, and 360 are, and are, idler rollers, but because they are not driven, they are not capable of driving the substrate S with uniform tension. For this reason, all of the pinch rollers 356, 358 and 360 are attached to the underside of the cover 312, spacers 362 are employed to determine the downward extent of each pinch element, and the number of spacers 362 mounted with the intermediate pinch roller 356 decreases with successive rollers in the downstream direction of travel of the substrate S, thereby decreasing the depth of successive pinch rollers, resulting in a decrease in the angle of inclination of the substrate as it advances over its successive applicator face, thereby reducing the amount of friction that results, which results in increased tension. Uniform tension is beneficial because it results in the amount of foam applied at each applicator being as close to a uniform amount as possible. A change in the tension in the substrate will result in a change in the amount of foam applied to the surface of the substrate by the applicator. The amount of tension in the substrate is controlled by the relative drive speeds of the rollers in the entry roller assembly 316 and the rollers in the exit roller assembly 332, and also by reducing the number of pads 362 in the pinch roller sequence. In this regard, it is desirable that the amount of increase in the tension in the substrate as it travels through the apparatus be limited to the range of 1 to 2.5 times the tension in the substrate as it enters the apparatus. Spacers 362 may be any size and number that provides optimal results. For example, 1/8, 3/16, or 1/4 inch thick spacers may be used and reduced in number from about 6 to about 3, depending on the circumstances, to provide satisfactory results.

It is desirable that the spacing between the applicators 344 be sufficient to allow the foam to partially collapse between the applicators so that the dye will be effectively absorbed in the surface fibers of the fabric substrate before the foam is applied by the next applicator. This, combined with the reduced depth of the intermediate pressure roller 356, results in a relatively uniform application of foam from each applicator without absorbing a significant amount of moisture into the fabric. With the apparatus of the present invention, the amount of dye foam normally applied when using one applicator can now be divided and applied in small portions per applicator. For example, in the illustrated apparatus, one fifth of the foam dye is applied by each applicator, with each application being only to the substrate surface, rather than having the foam dye penetrate into the fabric in large amounts as when all of the foam dye is applied in one applicator. In a typical operation, the moisture pick-up using the apparatus of the present invention may be 15% of the fabric weight compared to 90% to 100% moisture pick-up in a conventional dyeing operation. Thus, the time consuming drying process can be significantly reduced, or eliminated, while waste water is also minimized.

To limit the outflow of foam to the width of the substrate S, side seals 364 and 366 similar to the side seal 60 in the embodiment of fig. 3 and 4 are provided. The edge of the traveling substrate may be sensed by a sensing fork (as described in previous embodiments) which is labeled with reference numeral 56 in fig. 3, or various types of electronic sensors may be used.

When the apparatus 300 is used to apply leuco-state dye where an inert atmosphere is required, the bottom wall 310 is located near the upper limit of the applicator 344 in order to minimize the volume of the chamber 344 and thus the amount of inert gas that needs to be maintained within the chamber. Also, when a leuco-state dye is used, the spacing between the inlet end seal 328 and the first applicator 344 is important because it allows at least a portion of the oxygen that may be trapped in entering the substrate to dissipate. Similarly, the spacing between the last applicator and the outlet end seal 330 is also important because it allows the foam to at least partially collapse before the substrate is exposed to the atmosphere so that the dye is securely attached to the substrate.

As shown in fig. 11, any unapplied foam that has accumulated as a liquid in chamber 314 drains through side conduit 368 to flap 370, and flap 370 may be opened manually or automatically as desired. Similarly, a drain valve 374 (FIG. 10) on the drain manifold 354 may also be opened to drain accumulated liquid from the drain manifold 354.

Monitoring and control of the operation of the apparatus 300 is performed by an operator O using a control panel 378, the control panel 378 being mounted on the inlet side of the apparatus 300.

The embodiment of the apparatus 300 of FIGS. 10-18 may be used to apply leuco-state dyes or non-leuco-state dyes with substantially equivalent benefits. When dyeing with leuco-state dye is performed with the apparatus 300, the chamber need not be formed airtight, or the end seals need not provide hermeticity, or the cover need not be sealed in place. Rather, ambient air is present both before and after the lid is closed and can enter through unsealed openings, including openings resulting from disconnection from an inert gas source. Also, when the foam collapses, air is released therefrom.

Fig. 15, 16 and 17 show the sequence of operations in opening the cover 312. Fig. 15 shows that during operation of the device, the hood is closed. The first step in opening the cover is to raise the cover 312 vertically. This is achieved by the extension of a short front piston-cylinder mechanism 380, which is located at the bottom of the front leg 304 of the device 300. These short piston-cylinder mechanisms 380 are attached to the lower end of a long front piston-cylinder mechanism 382. The upper end of the front piston-cylinder mechanism 382 is attached to the front corner of the hood 312, and the hood 312 is raised by the extension of the short front piston-cylinder mechanism 380, while by the extension of the short rear piston-cylinder mechanism 386 mounted on the rear corner extension 388 of the housing 302. The upper end of the rear piston-cylinder mechanism 386 is attached to a corner pivot 390 of the cover 312, where the extension of the rear piston-cylinder mechanism 386 raises the rear of the cover 312 the same height as the front of the cover is raised by the front piston-cylinder mechanism 380. The initial vertical elevation of the cover 312 is particularly desirable when the cover 312 is sealed during operation.

After the initial vertical raising of the cover 312, the front piston-cylinder mechanism 382 is fully extended to raise the front of the cover 312, during which the cover pivots about the rear pivot 390 to swing the cover 312 open to the position shown in FIG. 17. As the cover 312 approaches its upper limit of pivoting, a latch plate 394 secured at some inclination to the sides of the top of the cover 312 engages the latches 396 until the latch plate 394 displaces the latches 396 sufficiently for the latches 396 to engage within the openings 400 of the latch plate 394, thereby retaining the cover 312 in the open position shown in fig. 17, with the latches 396 pivotally mounted on reciprocating cross bars 397 mounted on and extending between the upstanding posts 398. An arm 402 fixed to and extending from one end of the rod 397 has an outer end 404 attached to a spring mechanism 406, the spring mechanism 406 having one end 408 fixed to a reciprocating cross bar 397, and the other end 410 attached to a bracket 412 on the post 398. The spring mechanism 406 normally urges the cross-bar 397 to position the latches 396 into a downwardly extending position, as shown in fig. 10. The connection of the latches 396 and latch plates 394 may be manually or mechanically disengaged when it is desired to pivot the cover 312 downwardly to its closed position.

The spacer block 362 described in relation to the various forms of the invention described and illustrated with reference to figures 10-18 may also be used with the forms of figures 1-9 for the same purpose and to obtain the same benefits. Moreover, all forms of the invention described herein may be used with leuco-state dyes, and also with other dyeing systems that are not leuco-state systems (e.g., sulfur dyes, vat dyes, conventional aqueous textile dyes, and any other dye that can be applied in foam form), and a heater may be included to obtain the best effect of the particular dye selected. Also, the woven fabric substrate may be a woven, knitted or non-woven material of cellulose or non-cellulose, or a mixture of such materials. Furthermore, the applicators in any of the forms of the present invention may each be supplied independently or in combination by dedicated independent foam generators to simultaneously supply different dyes and chemicals to the substrate and apply these materials in a layer.

In the embodiment of FIGS. 1-9 and 10-18, the applicators 96, 98, 100, 102, and 104 and the pinch rollers 110, 112, 114, and 116 in the embodiment of FIGS. 1-9, and the applicator 344 and the pinch roller 356 in the embodiment of FIGS. 10-18 are all arranged in a horizontal sequence for feeding the substrate S horizontally through the apparatus.

These embodiments can be modified to reposition the apparatus in an upright position, as shown in figures 19 and 20, as compared to the embodiments of figures 10-18, in order to significantly reduce the footprint, allow for more convenient viewing of the interior of the apparatus, allow access to the apparatus for repair and maintenance of components, and eliminate the risk of the hood falling off when an operator is working within the apparatus. In this modification, the applicator 344 is mounted on the vertical wall 414 and the pinch roller 356 is mounted on the opposite vertical wall 416. These vertical walls 414 and 416 form chamber walls.

In the embodiment shown in fig. 19 and 20, one of these vertical walls, wall 416, is mounted on horizontally extending guide rods 418 on each side thereof and at the top thereof. The vertical wall has a follower element 419 for supporting the wall 416 for movement away from the opposite wall 414 upon release of the fastener 420, the fastener 420 maintaining the wall in a seal during normal operation of the apparatus.

The embodiments of figures 1-20 are particularly beneficial in foam dyeing of textile fabric substrates, such as in indigo dyeing of denim fabric subsequently used to make jeans. These embodiments are not readily adaptable to dyeing yarns first and then weaving the dyed yarns into a fabric. However, more preferred embodiments are shown in FIGS. 21-28, which are particularly suited for foam dyeing yarns in sheet form, and these more preferred embodiments may also be used for foam dyeing of textile substrates. In this embodiment, the substrate S is fed vertically through the apparatus 500 with vertically spaced foam applicators 502, 503 in combination with a plurality of pinch roller pairs 504, 505, the plurality of pinch roller pairs 504, 505 providing feed control of the substrate. These components of the apparatus are preferably enclosed within a housing 506, the housing 506 being sealed to form a chamber 508, the chamber 508 containing the inert atmosphere necessary for applying the reduced leuco-state dye (e.g., indigo) to a substrate, which may be cotton yarn, which is then woven into a denim fabric.

The device 500 is mounted on a base 510, the base 510 supporting an upright frame 512, the frame 512 being formed from bottom perimeter bars 514, vertically extending corner bars 516, and top perimeter bars 518, all of which are fastened together to form the upright rigid frame 512. The frame 512 is enclosed to form a housing 520 having an interior chamber 508 comprised of a bottom wall 522, a top plate 524, and four side walls 521, wherein the bottom wall 522, top plate 524, and four side walls 521 are comprised of a transparent material (e.g., plexiglas) so as to allow viewing of the interior components during operation of the apparatus. These walls 522, 524, and 526 are sealingly fastened to the bottom, top, and corner rods 514, 516, and 518 of the frame 512 by fasteners 528 to seal the interior chamber 508 from the atmosphere.

Mounted within the chamber 508 and on an upstanding inner sidewall 530 of a transparent material (e.g., plexiglas) are a plurality of roller pairs to form a nip. In the illustrated embodiment, there are three pairs of nip rollers 504, 505. The rollers 504, 505 in each pair are driven in opposition to provide a downfeed of the substrate S. The roller pairs 504, 505 are synchronously driven by a drive motor 534 and a belt 536 interconnecting the drive motor to one roller in each pair 504, 505. Any other suitable drive may be used and both rollers in each pair may be driven, except that only one roller may be driven.

A pair of horizontally disposed foam applicators 502, 503 are mounted to the interior side wall 530 above the pair of pinch rollers 504, 505 and extend across the frame 512. The applicators of the pair have the foam dispensing faces 538 vertically spaced apart and horizontally overlapping so as to deflect the traveling substrate S relatively across the face 538 of the applicator to ensure deposition of the dye in foam form on the substrate surface. For this purpose, the applicator extends across the entire width of the substrate.

Such a pair of foam applicators 502, 503 is disposed between adjacent pairs of pinch rollers 504, 505.

To maintain an inert atmosphere within the housing 506 while allowing entry and exit of the substrate and substantially preventing atmospheric air from entering the chamber as the substrate enters, passes, and exits the housing 506, an inlet seal 540 and an outlet seal 542 are provided, through which the substrate S enters the housing 506 and exits the housing 506 through the inlet seal 540 and the outlet seal 542. The inlet seal 540 and the outlet seal 542 may be configured in any suitable manner. Fig. 26 shows one form of seal in which support blocks 544 are mounted on the outside of the top and bottom of the housing 506. The blocks 544 have opposing cavities in which resilient tubes 548 are mounted for positioning the tubes sealingly against each other within the space 550 between the blocks 544 through which the substrate travels for entry into the housing 506 or exit from the housing 506.

When used to apply dye in foam form to a traveling sheet of textile yarn, the feed beam of yarn is positioned for feeding the sheet of yarn to the apparatus 500 by guide rollers 554, the guide rollers 554 being mounted between horizontal extensions 556 at the top of the frame. The yarn sheet then passes through a comb 558, the comb 558 ensuring that each individual yarn is in an unwound, separated state as it travels to an input roller assembly 560, the input roller assembly 560 having rollers mounted in bearings 562 on opposite sides of the top of the frame 512 through which the yarn sheet travels to the inlet seal 540 of the housing 506.

The yarn sheet then travels between the upper pair of foam applicators 502, 503, with the pair of foam applicators 502, 503 overlapping horizontally to ensure proper contact for dispensing foam onto the opposite surface of the yarn sheet. A plurality of vertically spaced pinch roller pairs 504, 505 feed the yarn sheet through the housing and apply tension and pressure to maintain separation of the yarn in the sheet, preventing eversion and twisting of the yarn as the sheet travels through the housing 506. The driving of the pinch roller pairs provides a controlled tension in the yarn sheet that is subject to an increase in tension as the yarn sheet advances across successive applicator pairs. If this build-up of tension is sufficient to be undesirable, the applicators can be adjusted so that the overlapping portions of the foam dispensing face can be sequentially reduced, thereby reducing the progressively increasing tension applied by the applicator face as the yarn sheet advances through the chamber 508.

The yarn sheet exits the housing through outlet seal 542 below the lower pinch roller pair 504, 505 to the trailing pinch roller pair 564, which is mounted in the base 510 immediately below the outlet seal 542. One of the pull rolls is driven by a motor 534 to draw the yarn sheet from the housing 506.

From the pull roll 564, the yarn sheet travels laterally outward from the base 510, around a pair of vertically spaced idler rolls (having a lower roll 566 and an upper roll 568, the sheet being guided under the lower roll 566 and over the upper roll 568), from which it travels to a driven take-up drum 570, whereby the dyed yarn sheet is wound on the take-up drum 570.

The connection of the drive motor 534 to the belt 536 constitutes a roller drive control for coordinated driving of the pinch roller pair in order to maintain tension in the substrate.

The applicators 502, 503 are preferably parabolic in shape, as described with respect to the applicators in the previous embodiments herein, and as disclosed in U.S. patent No.4,655,956. This may be a single parabolic shaped applicator, but preferably, to minimize space, these applicators are formed from a plurality of adjacent small parabolic shapes 572, as shown in fig. 28. These multi-parabolic applicators extend horizontally and each has a foam entry opening 574 near the horizontal position near the applicator foam dispensing face 538. The interior of each parabolic shape 572 has a horizontally extending medial parabolic divider 576 that is spaced from the outer parabolic limits of the applicator interior 578, around which the incoming foam passes and is dispensed to the foam dispensing face. The parabolic shape 572 facilitates a path of the foam through the applicator to the dispensing surface that is of somewhat uniform length such that there is no noticeable difference in the break-up as the foam travels through the applicator to the dispensing surface.

The horizontal placement of the applicator has the added benefit that it is easier to flush and break down the foam than if the dispensing face were placed vertically along the applicator at the top of the applicator.

To allow easy access to the interior of the housing 506 for inspection maintenance or repair of components therein, the housing may be configured such that the side walls 526 of the housing slide open, with the side walls 526 parallel to the surface of the traveling yarn sheet. The upstanding inner side wall 530 is vertically bisected, with one roller of each pair and one applicator of each pair being mounted on one half of the inner side wall. As can be seen in fig. 27, the housing side wall 526, one half of the inner wall 530, and one of each pinch roller pair and applicator pair may be separated from the other components to provide access space 580 for operator access for inspection, repair, and maintenance of equipment components.

The operation of the device 500 is controlled by a conventional controller contained within a control box 582, the control box 582 having a dial 584 for manual adjustment. The oxygen/inert gas composition of the atmosphere within chamber 508 is recorded on gauge 586 while the gas pressure within chamber 508 is recorded on another gauge 588.

After the pieces of yarn are dyed, the yarns may be conventionally treated in a fabric, which may be re-dyed, if desired, in an apparatus such as the embodiments of FIGS. 1-20.

From the above description of the invention, those skilled in the art will readily appreciate that the invention is capable of broad uses and applications. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Thus, while the present invention has been described herein in detail with respect to the preferred embodiments, it is to be understood that this disclosure is only illustrative of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The above disclosure is not intended, and should not be taken, to limit the present invention or otherwise exclude any other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the following claims and the equivalents thereof.

Claims (40)

1. An apparatus for dyeing a traveling textile substrate with a leuco-state dye, wherein the textile substrate comprises cellulose fibers and the leuco-state dye is applied in a foam state, the apparatus comprising:

a housing having an interior chamber sealed from atmospheric air through which the substrate travels from an inlet having a seal and through which the substrate enters the chamber to an outlet also having a seal through which the substrate exits the chamber;

an inert gas source in communication with the chamber to provide an inert environment within the chamber;

at least one foam applicator having an applicator face within the chamber and extending across the width of the substrate for applying a foam containing the leuco-state dye to the substrate within the chamber; and

a foam source comprising the leuco-state dye in the absence of any significant amount of oxygen, the foam generator being in communication with the applicator for supplying the foamed leuco-state dye to the applicator.

2. The apparatus of claim 1, wherein the foam contains a small controlled amount of oxygen.

3. The apparatus of claim 1, wherein the inert gas source is under pressure to provide a pressurized inert environment within the chamber.

4. The apparatus of claim 1, wherein the at least one applicator is spaced from the inlet so as to provide a free release area of the substrate in which air trapped in the interstices of the substrate is allowed to escape.

5. The apparatus of claim 1, wherein the at least one applicator is spaced from the outlet to allow the foam on the substrate to collapse and deposit the dye in the colorless state on the substrate before the substrate exits the chamber and is exposed to air.

6. The apparatus of claim 1, wherein the at least one applicator comprises a plurality of applicators, the plurality of applicators being spaced apart to allow the foam to at least partially collapse and to allow the dye in the leuco-state to at least partially deposit on the substrate prior to application of the foam by a subsequent applicator.

7. The apparatus of claim 6, further comprising a hold down element between the applicators for engaging the substrate to displace the substrate between the applicators to maintain the substrate in foam receiving engagement with the applicator face.

8. The apparatus of claim 1, wherein the at least one applicator is parabolic in shape for distributing foam evenly across the width of the substrate.

9. The apparatus of claim 8, wherein said at least one applicator comprises a plurality of said parabolic shaped applicators spaced apart to allow foam to at least partially collapse and allow said leuco-state dye to at least partially deposit on said substrate prior to application of foam by a subsequent applicator.

10. The apparatus of claim 9, further comprising a hold down element between the applicators for engaging the substrate to displace the substrate between the applicators to maintain the substrate in foam receiving engagement with the applicator face.

11. The apparatus of claim 1, wherein the inert gas comprises nitrogen, and the foam generator generates a foam of the leuco-state dye comprising primarily nitrogen, wherein the nitrogen assists in replenishing the nitrogen contained within the chamber when the foam collapses.

12. The apparatus of claim 1, wherein the textile substrate is a woven denim fabric, the leuco-state dye is an indigo dye applied in as little weight as about 5% to 30% of the fabric weight.

13. The apparatus of claim 10, wherein the housing has an openable cover sealingly mounted thereon, the hold-down element being mounted on a frame, the frame being movable to move away from the space when the cover is opened.

14. The apparatus of claim 10, wherein the compaction member is an idler roller under which the substrate travels.

15. An apparatus for dyeing a traveling textile fabric substrate, comprising:

a housing having an interior chamber through which the substrate travels from an inlet to an outlet, wherein the substrate enters the chamber through the inlet and the substrate exits the chamber through the outlet;

an entry roller assembly for delivering the advancing substrate to the inlet;

an exit roller assembly for pulling the traveling substrate from the chamber;

a plurality of spaced apart foam applicators located within the chamber having applicator faces extending in a transverse direction of the traveling substrate for incrementally applying dye in foam form onto the surface of the substrate, the applicators being spaced apart so as to allow foam to at least partially collapse between the applicators; and

a plurality of laterally extending hold-down elements located within the chamber, the hold-down elements extending between the applicators in a transverse direction of the traveling substrate and extending below a level of the applicator face so as to guide and hold the substrate down against the applicator face.

16. An apparatus for dyeing a traveling textile substrate according to claim 15 and characterized further in that said holddown elements are idler rollers.

17. An apparatus for dyeing a traveling textile fabric substrate according to claim 15 and characterized further in that said holddown elements are inverted applicators.

18. An apparatus for dyeing a traveling textile fabric substrate according to claim 15 and characterized further in that said holddown elements progressively decrease in depth in a downstream direction of travel of said substrate between applicators to decrease the angle of inclination of said substrate as it travels over successive applicator faces to minimize an increase in tension of said substrate as it travels through said apparatus across successive applicator faces.

19. An apparatus for dyeing a traveling textile fabric substrate according to claim 15 and characterized further in that said internal chamber is rendered substantially airtight by inlet and outlet air seals, said chamber being capable of containing an inert gas for effective application of the leuco-state foam dye to the textile fabric substrate without significant oxidation of the dye until the substrate exits said apparatus.

20. An apparatus for dyeing a traveling textile fabric substrate according to claim 17 and characterized further in that said holddown elements are mounted to said housing with spacers therebetween, the number of said spacers of each holddown element between said applicators decreasing in the direction of travel of said substrate.

21. An apparatus for dyeing a traveling textile fabric substrate according to claim 15 and characterized further in that said housing includes an openable cover and said pressure rollers are mounted on said cover.

22. An apparatus for dyeing a traveling textile fabric substrate according to claim 19 and characterized further in that said housing includes an openable cover and said pressure rollers are mounted on said cover.

23. An apparatus for dyeing a traveling textile fabric substrate according to claim 15 and characterized further in that a first pinch roller precedes the first of said applicators in the direction of travel of said substrate and a last pinch roller follows the last of said applicators, said first pinch roller and said last pinch roller guiding said substrate at the same level at which said substrate exits said entry roller assembly and enters said exit roller assembly.

24. An apparatus for dyeing a traveling textile fabric substrate according to claim 15 and characterized further in that said chamber is open to said atmosphere.

25. An apparatus for dyeing a traveling textile fabric substrate according to claim 15 and characterized further in that said outlet is spaced below said inlet and said plurality of spaced foam applicators are vertically spaced between said inlet and said outlet.

26. An apparatus for dyeing a traveling textile fabric substrate according to claim 25 and characterized further in that said housing has a side facing said traveling substrate and openable to allow access to said foam applicator and said holddown elements.

27. An apparatus for dyeing a traveling textile fabric substrate according to claim 26 and characterized further in that said holddown elements are mounted in said housing for opening movement with the sides of said housing to permit access between said holddown elements and said foam applicators.

28. An apparatus for dyeing a traveling textile substrate, comprising:

a housing having an interior chamber through which the substrate travels from an inlet to an outlet and through which the substrate exits the chamber;

an entry roller assembly for delivering the advancing substrate to the inlet;

an exit roller assembly located below the entry roller assembly for pulling the substrate from the chamber;

a plurality of vertically spaced roller pairs forming nips for feeding a substrate therebetween from said entry roller assembly to said exit roller assembly through spaces between adjacent roller pairs, at least one roller of each pair being driven;

at least one foam applicator located between adjacent pairs of rollers and extending in a cross-machine direction of the traveling substrate for incrementally applying a dye in foam form to the substrate surface; and

a roller drive controller for coordinated driving of the roller pairs to maintain tension in the substrate.

29. An apparatus for dyeing a traveling textile substrate according to claim 28 and characterized further in that each of said at least one foam applicators comprises a pair of opposed foam applicators for applying foam to opposite sides of said substrate, each of said pairs of applicators having vertically spaced and horizontally overlapping faces for oppositely deflecting said substrate traveling across said applicator faces.

30. An apparatus for dyeing a traveling textile substrate according to claim 28 and characterized further in that said housing has a side facing said traveling substrate openable to allow access to said foam applicator.

31. An apparatus for dyeing a traveling textile substrate according to claim 29 and characterized further in that one roller of each said pair of rollers is mounted in said housing for opening movement with the side of said housing to permit access between the rollers of said pair of rollers.

32. An apparatus for dyeing a traveling sheet of textile yarn, comprising:

a housing having an interior chamber through which the yarn passes from an inlet to an outlet and through which the yarn exits the chamber;

an entry roller assembly for feeding the advancing yarn to the inlet;

a take-off roller assembly located below the entry roller assembly for drawing the yarn from the chamber;

a plurality of vertically spaced roller pairs forming nips for passing the yarn therebetween from the entry roller assembly to the exit roller assembly through spaces between adjacent roller pairs, at least one roller of each roller pair being driven;

at least one foam applicator located between adjacent pairs of rollers extending in a cross-machine direction of the advancing yarn for incrementally applying dye in foam form onto a surface of the yarn; and

a roller drive control for coordinated driving of the roller pairs to maintain tension in the yarn.

33. An apparatus for dyeing a traveling sheet of textile yarns according to claim 32 and characterized further in that said at least one foam applicator includes a pair of opposed foam applicators for applying foam to opposite sides of said traveling sheet of yarns, each said pair of applicators having vertically spaced and horizontally overlapping foam dispensing faces for oppositely deflecting said traveling sheet of yarns across said applicator faces.

34. An apparatus for dyeing a traveling sheet of textile yarns according to claim 29 and characterized further in that said amount of overlap of said applicator faces decreases in the direction of travel of said yarns as said yarns travel over successive applicator faces to minimize an increase in the tension of said yarns as they travel across successive applicator faces through said apparatus.

35. An apparatus for dyeing a traveling sheet of textile yarns according to claim 32 and characterized further in that said housing has a side facing said traveling sheet of textile yarns and openable to allow access to said foam applicator and said pair of rollers.

36. An apparatus for dyeing a traveling sheet of textile yarns according to claim 35 and characterized further in that one roller of each said roller pair and one applicator of each applicator pair are mounted in said housing for opening movement with the sides of said housing to permit access between the rollers of said roller pairs and between said applicators of said applicator pairs.

37. An apparatus for dyeing a traveling sheet of textile yarns according to claim 32 and characterized further in that said yarns are cellulosic, said dye is in a colorless state, said interior chamber is sealed from atmospheric air by said housing so as to contain an inert environment, said inlet and said outlet are formed so as to provide a seal to substantially prevent atmospheric air from entering said chamber.

38. An apparatus for dyeing a traveling sheet of textile yarns according to claim 32 and characterized further in that said applicators are parabolic in shape for distributing foam evenly across the width of said sheet of textile yarns.

39. An apparatus for dyeing a traveling sheet of textile yarns according to claim 38 and characterized further in that each said parabolic shaped applicator includes a plurality of parabolic shapes aligned across the lateral extent of said sheet of yarns.

40. An apparatus for dyeing a traveling sheet of textile yarns according to claim 32 and characterized further in that there is at least one foam applicator between said entry roller assembly and said pair of rollers.