WO1997004156A1

WO1997004156A1 - Flooded nip padder

Info

Publication number: WO1997004156A1
Application number: PCT/US1996/011522
Authority: WO
Inventors: Kenneth Stephen Freund; James Stephen Bailey
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 1995-07-17
Filing date: 1996-07-11
Publication date: 1997-02-06

Abstract

An improved squeeze roll padder system involving three horizontal rollers (12, 14, 16) forming a pair of nips (20, 22) and a fluid trough (28) wherein the web of textile (24) to be permeated and/or saturated with liquid additive operatively passes upwardly through one nip (20), across the upper surface (26) of the center roller (12) within the fluid containing trough (28) and then downwardly through the second nip (22). Such a configuration is useful to achieve efficient de-watering and uniform impregnation of the textile on a commercial scale while simultaneously minimizing finish foaming and the potential for spills.

Description

TITLE

FLOODED NIP PADDER

BACKGROUND OF THE INVENTION

1. Field of the Invention:

This invention relates to an improved squeeze roll padder system and a method of using the same. More specifically but not by way of limitation, the invention relates to a method and apparatus for permeating textile materials with liquid involving three horizontal rollers forming a pair of nips and a fluid trough.

2. Description ofthe Related Art:

It is generally known and a commercially accepted practice to convey a web of textile material through a liquid bath in order to permeate or saturate the web with a liquid. It is also generally known to strip off excess liquid after the web of textile material has been permeated or saturated. Typically such prior art processes are performed in a bath which contains a large quantity of liquid and the concepts of expelling air or moisture from the incoming web, impregnating the resulting web with the desired liquid additive and then removing any excess liquid are treated as separate and independent concepts or events in order to insure reduced variability and/or lack of uniformity of impregnation. It has also been recognized that in certain types of applications and in certain situations, some advantages and benefits may be achieved by performing liquid impregnation of a web of textile material in a small liquid bath such as that formed as the web passes vertically upward through a horizontal nip between two rollers. For example, in U.S. Patent No. 5,046,208 a tubular knitted fabric is ballooned below and prior to passing upward through a flooded nip containing a liquid additive being applied to the knit. Also in U.S. Patent No. 5,195,201 a web of textile material is permeated with a liquid by causing the web to move upwardly through the nip of two squeezing rolls having the liquid bath and the surplus liquid is then expelled from the web by two additional rolls installed above the bath. The present invention is viewed as an improved squeeze roll padder system and process that combines the advantages and benefits of the use of a flooded nip liquid bath and the traditional concepts of expulsion of air or moisture, impregnation of desirable liquid additive and control of excess fluid retention as the web of textile material passes through the flooded nip.

SUMMARY OF THE INVENTION

The improved flooded nip textile padder system according to the present invention and the associated method of use involves a set of three horizontal rolls forming a single liquid additive trough wherein the web of textile moves upwardly through the squeezing nip formed between two of the rolls and then loops over the centrally located roll and downwardly through the second nip formed between this center roll and the third roll. In this manner the web of fabric or textile material experiences compression and expulsion of air or moisture, expansion and impregnation of desirable liquid additive and control of excess fluid retention while completely submerged in the fluid containing trough formed by the pair of flooded nips associated with the set of three horizontally contacting roll. This in combination with the ability to employ a smaller diameter roll and hence higher nip pressures because of narrower nip footprints leads to a more versatile and reproducible overall system as will be explained and exemplified in more detail latter.

Thus the present invention provides an improved flooded nip textile padder system comprising in combination:

(a) three horizontal cylindrical rollers positioned in operative contact with each other such as to have parallel axis of rotation, wherein said three rollers consist of a center roller displaced below the top of a pair of outboard rollers thus forming a nip between said center roller and each outboard roller and forming a trough above the center roller for receiving and distributing a fluid;

(b) a web of textile operatively passing upwardly through the nip formed by said center roller and one of said outboard rollers, across the upper surface of said center roller within the fluid dispersing trough and downwardly through the nip formed by said center roller and the other of said outboard rollers;

(c) a fluid in said trough immersing said web; (d) a means operatively attached to said horizontal rollers for applying a compressive force on said web passing through the nips formed by said rollers; and (e) a means operatively attached to said horizontal rollers for advancing said web through the flooded nip textile padder system.

In one preferred embodiment of the present invention the flooded nip textile padder system further comprises a fourth horizontal roller operatively in contact with an outboard roller such as to form a nip that squeezes fluid carried upwardly from the trough back to the trough and in another embodiment the diameter ofthe center roller is smaller than the diameters ofthe outboard rollers.

Thus, the method of permeating textile material with a liquid according to the present invention comprises the steps of:

(a) providing three horizontal cylindrical rollers positioned in operative contact with each other such as to have parallel axis of rotation, wherein said three rollers consist of a center roller displaced below the top of a pair of outboard rollers thus forming a nip between said center roller and each outboard roller and forming a trough above the center roller for receiving and distributing a fluid;

(b) passing a web of textile upwardly through the nip formed by said center roller and one of said outboard rollers, across the upper surface of said center roller within the fluid dispersing trough and downwardly through the nip formed by said center roller and the other of said outboard rollers;

(c) maintaining a fluid in said trough for immersing said web of textile; and (d) recovering said web of textile permeated with said fluid.

It is an object of the present invention to provide an improved squeeze roll padder system involving directly opposed loading at the roller nips for more even compression and treatment of wide span fabric widths. It is an associated object to provide the ability to select and control the diameter and thus the crown as well as the hardness of the respective rollers allowing for more even foot print across the nips between rollers. It is a further object to provide such a squeeze roll padder system that virtually eliminates historical problems associated with foaming, fluid carry-over as well as potential for spill. Fulfillment of these objects and the presence and fulfillment of additional object will be apparent upon complete reading ofthe specification and drawing including the attached claims. BRIEF DESCRIPTION OF THE DRAWING

Figure 1 represents a schematic cross sectional view of a typical squeeze roll padder system according to the present invention illustrating a center roller, two outboard rollers, a seal roller, the fluid, the textile to be treated and their relative movement during treatment.

Figure 2 represents a side view of a commercial squeeze roll padder system according to the present invention illustrating the respective rollers and the means for applying compressive force as well as means to drive the system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The squeeze roll padder according to the present invention, how it functions and how the overall system differs from prior art systems as well as its advantages relative to the prior art can perhaps be best explained and understood by reference to the drawing. As illustrated in Figure 1, the roller system (generally designated by the number 10) involves a stack of three horizontal rollers 12, 14 and 16 along with an optional fourth seal roller 18. The smaller diameter center roller 12, in this specific embodiment, makes longitudinal contact on the right with larger diameter roller 16 thus forming an inlet nip 20 there between. Similarly, the smaller diameter center roller 12 makes longitudinal contact on the left with larger diameter roller 14 thus forming an exit nip 22 there between. A sheet or web of textile material 24 enters the inlet nip 20 from the underside and then loops over the top surface 26 of the center roller 12 before exiting downwardly through nip 22. As further illustrated, the smaller diameter center roller 12 is configured relative to the outboard rollers 14 and 16 such that the top surface 26 of roller 12 is displaced below the tops of the larger diameter outboard rollers 14 and 16. In this manner the stack of horizontal rollers define and create a fluid retaining trough along the longitudinal direction of the rollers (i. e., perpendicular to the cross sectional view) and above the center roller 12. This trough is filled with a fluid 28 which makes contact with the sheet 24 as it passes over the top of roller 12.

During operation the sheet or web of material 24 which is to be treated with fluid 28 is first compressed at the inlet nip 20 which serves to evacuate any voids associated with the textile. The sheet 24 then exits the nip 20 into a flood bath of fluid 28. While exiting the first nip 20 the sheet expands causing a suction and wicking effect which tends to draw the fluid 28 into the material 24 and brings finish into the structure. The web of material 24 then proceeds to the second nip 22 where any excess fluid 28 is squeezed off. Any fluid 28 that tends to be carried upward by roller 16 is squeezed by the nip between seal roller 18 and roller 16 thus reducing fluid loss from the trough.

As further illustrated in Figure 2, the horizontal three roll stack 10 is conveniently mounted and supported in a frame 30 such that the entire stack is driven (rotated) by a single roller. In this particular embodiment, the second roller 32 (the furthest left roll in Figure 2) is driven or rotates clockwise by a single motor 34 mounted to the opposite side of the frame 30 as shown in silhouette by use of dashed lines. The motor 30 thus serves as a means operatively attached to the horizontal roller system for advancing the web of textile 36 through the flooded nip textile padder system. It should be readily appreciated that other mechanisms and mechanical systems as well as energy sources, all as generally known in the art, can be substituted for the motor for the purpose of turning the stacked roller system and as such should be considered as equivalent means for advancing the textile through the roller system.

The middle or center roller 38 in Figure 2 is pivotally mounted to frame 30 by an adjustable support bracket 40 and as such can be compressed between the outboard rollers 32 and 42. Outboard roller 42 is slidably mounted to an extension 44 of the frame 30 such that it as well as the seal roller 46 can be adjusted horizontally toward or away from the rest ofthe stack of three horizontal rollers 10 thus affording control ofthe degree of compression at the respective nips created between the pairs of touching rollers. Typically the horizontal compressive force can be supplied by any means generally known in the art, including by way of example but not by limitation, hydraulic or pneumatic cylinders, mechanical tension such as springs, lever arms and weights, threaded advancing members or the like. Preferably the axle of the roller 42 is loaded towards the center roller 38 by a pair of air stroke actuators acting through a pair of pivot arms (not shown) wherein by way of example 90 psig air results in typically 150 PLI (pounds per linear inch) across a width of 36 inches (see Example below). The loading of the seal roller 46 is achieved in a manner analogous to that employed for horizontal compression or merely by virtue of static weight conveniently applied on the seal roller. The actual additives or fluid (i. e., liquid phase) making contact with the web of textile material for purposes of this invention can be generally any such compounds or solutions as generally known in the art. The fluid can be confined to the trough created by the horizontal rollers by the use of appropriately positioned end-caps and the like or delivered to the trough at a controlled flow rate such as to immerse the textile with or without end-caps. It should be further appreciated that the general concepts illustrated in the present invention can be repeated on a single textile material by using a plurality of tliree horizontal roll padder system in series and thus afford an even greater variety of treatments.

Also, the concept of having all compressive forces applied essentially in a single horizontal plane in combination with the use of a relatively smaller diameter center roller allows for individual selection and control of the respective hardness of each individual roller independent of the others. This in turn affords a certain degree of control of the respective nip compression for de¬ watering the incoming textile material at the first nip independent of the degree of expulsion of excess fluid at the second nip without substantial deleterious influence caused by roller flexing across the width ofthe set of three rollers (i. e., the respective compressions are not orthogonal but rather longitudinally opposed; such that predictable induced flexing occurs). Inherently this results in the ability of the instant system to be applied to much greater widths. In other words, the inherent symmetry associated with coplanar compression along a stack of coaxial rollers means that the crown of the roller across the length of the roller can be utilized to compensate for flex (not just stiffness) and hence greater widths can be spanned without dynamic change in the dimension ofthe nip gap and compression during use, all of which leads to marked improvement in the commercial use of such a padder system.

EXAMPLE In order to illustrate the improved squeeze roll padder system and method of use according to the present invention, a prototype system was installed on a 36 inch wide textile permeating line. The configuration consisted of two 8 inch diameter outboard rolls, one 4 inch diameter center roll and one 8 inch diameter seal roll assembled according to that which is presented in Figure 2. The first 8 inch roll was of a high durometer, 95 Shore A. The second 8 inch roll had a lower hardness of 75 Shore A. The hardness difference yielded a nip pressure differential between the first nip and the second nip. This differential produced the desired wet pickup for wet on wet finishing, (additional control of the amount of fluid padded onto the web can be achieved through adjustment of the liquid variables, such as concentration of liquid components or liquid viscosity). The seal roll prevented liquid from being carried over by the first roll. The whole stack was driven by the second outboard roll. Any slippage in the nip resulted in a positive draw from the first to second nip keeping the web tight. The small diameter center roll was free to spin and move on a pivot mounted to the frame. To the first outboard roll force was applied by two 8 inch diameter air stroke actuators (supplied by Firestone Industrial Products Co., Noblesville, Indiana) through two pivot arms. This configuration allowed up to 150 PLI (pounds per linear inch) compressive force with 90 psi air.

The advantages and benefits associated with the flood nip padder according to the instant invention are felt to be numerous and significant. For example, the mechanical configuration of the system is simpler than previously proposed squeeze roll padders. In particular only one drive is required to turn the whole stack and both nips are loaded by one force mechanism. Also, because the center roll is loaded by two outboard rolls it can be designed for smaller diameters than previous systems. A smaller diameter roll can achieve higher nip pressure because of its narrower nip footprint. A high nip pressure would result in more efficient de-watering or the like (i. e., both during evacuation of voids and control of excess squeeze-off). Furthermore, current experience with the squeeze rolls of the present invention indicate they do not produce wrinkles in the web while the amount of finish in the system is very low which means it comes to equilibrium very quickly and the potential for spills is low. An finally, finish foaming is significantly reduced because the web never leaves the bath so air is not carried into the finish.

Having thus described and exemplified the invention with a certain degree of particularity, it should be appreciated that the following claims are not to be so limited but are to be afforded a scope commensurate with the wording of each element ofthe claim and equivalents thereof.

Claims

I (we) Claim:

I. A flooded nip textile padder system comprising in combination:

(c) a fluid in said trough immersing said web;

(d) a means operatively attached to said horizontal rollers for applying a compressive force on said web passing through the nips formed by said rollers; and

(e) a means operatively attached to said horizontal rollers for advancing said web through the flooded nip textile padder system.

2. A flooded nip textile padder system of Claim 1 further comprising: a fourth horizontal roller operatively in contact with an outboard roller such as to form a nip that squeezes fluid carried upwardly from said trough back to said trough.

3. A flooded nip textile padder system of Claim 2 wherein the diameter of said center roller is smaller than the diameters of said outboard rollers.

4. A method of permeating textile material with a liquid comprising the steps of:

(a) providing three horizontal cylindrical rollers positioned in operative contact with each other such as to have parallel axis of rotation, wherein said three rollers consist of a center roller displaced below the top of a pair of outboard rollers thus forming a nip between said center roller and each outboard roller and forming a trough above the center roller for receiving and distributing a fluid; (b) passing a web of textile upwardly through the nip formed by said center roller and one of said outboard rollers, across the upper surface of said center roller within the fluid dispersing trough and downwardly through the nip formed by said center roller and the other of said outboard rollers;

(c) maintaining a fluid in said trough for immersing said web of textile; and

(d) recovering said web of textile permeated with said fluid.

5. A method of Claim 4 further comprising the step of providing a fourth horizontal roller operatively in contact with an outboard roller such as to form a nip that squeezes fluid carried upwardly from said trough back to said trough.

6. A method of Claim 5 wherein the diameter of said center roller is smaller than the diameters of said outboard rollers.