Textiles: manufacturing – Textile product fabrication or treatment – Fiber entangling and interlocking
Reexamination Certificate
2001-04-25
2002-09-03
Vanatta, Amy B. (Department: 3765)
Textiles: manufacturing
Textile product fabrication or treatment
Fiber entangling and interlocking
C028S167000
Reexamination Certificate
active
06442810
ABSTRACT:
SPECIFICATION
1. Technical Field
This invention generally relates to the field of hydroenhancing surface properties of textile fabric by subjecting it to hydrojet treatment, and more particularly, to improving the efficiency of fabric hydroenhancement methods and equipment.
2. Background of Invention
Prior hydroenhancement technology teaches that certain properties of woven or knitted fabrics, such as cover, yarn blooming, surface texture, hand, drape, etc., can be enhanced by impacting the surface of the fabric with rows of jet streams from a series of overhead manifolds as the fabric is conveyed on a support surface, as illustrated in
FIG. 2
, for example. Such conventional hydroenhancing equipment is described in greater detail in commonly-owned U.S. Pat. No. 4,967,456 of Sternlieb et al., issued on Nov. 6, 1990, entitled “Apparatus and Method For Hydroenhancing Fabric”, which is incorporated herein by reference.
Generally, the conventional view has been that the degree of enhancement is related to the amount of energy imparted to the fabric. That is, the more energy delivered to the fabric, the more pronounced the enhancement effect. For example, U.S. Pat. No. 3,493,462 to Bunting teaches that the degree of surface treatment is related to the total energy E expended per weight of fabric in a pass under a hydrojet manifold, as calculated by the following equation:
E=0.125 (YPG/sb), in hp.-hr./lb. of fabric, where
Y=number of hydrojets (orifices) per linear inch of manifold,
P=pressure of fluid in the manifold, in p.s.i.g.,
G=volumetric flow of fluid in cu.ft./min. per orifice,
s=speed of passage of fabric under the manifold, in ft./min., and
b=weight of fabric treated, in oz./sq.yd.
This equation provided by Bunting is a standard calculation used in the industry for energy expended in the hydrotreatment of a fabric.
The degree of enhancement imparted to the fabric can be measured in terms of the cover of the fibers in the fabric. Cover has an inverse relation to the air permeability of the fabric, which is measured in cu.ft./min./sq.ft. (cfm/ft
2
). The graph in
FIG. 1
illustrates the relationship, as is known conventionally, between the total energy expended in hydrotreatment and the resulting air permeability property of the treated fabric. The graph shows that as the total energy expended (in hp-hr/lb) increases, the air permeability (in cfm/ft
2
) of the fabric decreases and, hence, the degree of enhancement, i.e., the cover of the fabric, increases.
Conventional equipment for hydroenhancing fabric has employed high-speed processing lines having one or more manifolds in parallel across the width of fabric conveyed in a machine direction on a conveyor, as shown in
FIG. 2
, for example. A fabric web
12
is advanced through a weft straightener
14
, which aligns the fabric weft prior to processing, onto conveyor belt
22
driven on rollers
24
in a machine direction (arrow indicating a downstream direction) through a hydroenhancing station
16
. A plurality of manifolds
30
are spaced apart and aligned in parallel extending in a cross direction (normal to the plane of the figure) across the width of the conveyed fabric. Each manifold has a row of jet orifices
32
which emit jets of water downwardly to impact on one side of the fabric
12
. The belt
22
has a porous support surface (such as a wire or plastic mesh) for supporting the fabric while allowing fluid to drain down to a collector system
19
. The opposite side of the fabric may be treated in the same run by another hydroenhancing station
18
having a drum conveyor
34
and a series of manifolds
30
spaced around the drum circumferentially. Following hydroenhancement, the fabric
12
is advanced to a tenter frame
20
for drying under tension to produce a uniform fabric of specified width. A more detailed description of such hydroenhancing equipment is provided in commonly-owned U.S. Pat. No. 4,967,456 of Sternlieb et al., issued on Nov. 6, 1990, entitled “Apparatus and Method For Hydroenhancing Fabric”, which is incorporated herein by reference.
Conventional techniques for obtaining suitable hydroenhancement of fabric include using high pressures of fluid jetted from the manifold, large-diameter jet orifices or lowered processing speeds to impact high energies of fluid per area of fabric per unit of time, and/or multiple manifold configurations. However, the requirements for handling high fluid pressures or fluid energies or multiple manifolds can increase the equipment size and complexity, as well as equipment and maintenance costs, significantly. The use of high total delivered energies, say in the range of 1.0 or 2.0 hp-hr/lb, is also less efficient, as improvements in fabric enhancement tend to taper off with further increases in energy. The use of high delivered energies can also cause greater fabric shrinkage, and can exacerbate the problem of interference patterns generated on the surface of the fabric by making traces of the jet streams more prominent in contrast to the yarn spacing in the fabric.
Hydroenhancement technology is related to technology for hydroentanglement or hydraulic needling of a web of fibers to produce autogenously bonded nonwoven fabric. In hydroentanglement technology, it has been the practice to obtain the desired degree of fiber entanglement with high energy input to the web of fibers. For the production of large quantities of hydroentangled fabric, large-scale, high-speed hydroentanglement lines and multiple-manifold equipment have been employed to deliver the needed hydroentanglement energies to continuously running webs. This type of large-scale equipment has also been used for hydroenhancement. However, it has a large capital cost which may only be justified for operations that can utilize very high output rates. For diversified product lines, the enhancement of different types of fabric in medium to small quantities requires equipment that is less capital intensive, adaptable to different fabrics, and more efficient to operate.
It is therefore a principal object of the present invention to improve the efficiency of fabric hydroenhancement by employing equipment that is smaller in size, can be adaptably configured for different types of fabrics, and delivers fluid energies for hydroenhancement in an optimized manner without wasting energy. It is a specific object of the invention to obtain comparable or even improved enhancement of fabrics with equipment that is greatly reduced in cost to build, operate, and maintain. A further object is to provide improved methods and equipment for fabric hydroenhancement that allow greater flexibility in making process adjustments for enhancing different types of fabrics and types of surface treatments. Still further objects of the invention include reducing warp yarn shrinkage and eliminating interference patterns in hydroenhancement of fabric.
SUMMARY OF INVENTION
In the present invention, the efficiency of fabric hydroenhancement can be improved by treating fabric with fluid jets at low levels of fluid energy per pass in multiple passes over the fabric. This can be carried out with compact equipment designed to simulate multiple passes on the fabric, which is of smaller scale and significantly reduced cost than conventional hydroenhancing equipment.
In a preferred embodiment of improved hydroenhancing equipment in accordance with the invention, referred to herein as “jigging equipment”, a length of fabric is conveyed back and forth between a pair of unwind/windup reels on a sinuous path between a pair of manifolds for treating opposite sides of the fabric in multiple passes. The manifolds may be aligned at an angle to the vertical relative to support rolls supporting the fabric in order to allow convenient drainage of fluid away from the path of the fabric around the support rolls. This can eliminate the need for vacuum-suction removal of fluid. As an improvement to reduce equipment size, small-diameter solid support rolls may be used in treating certain type of fabrics.
The jigging equi
Greenway J. Michael
Lawrence Jackson
Malaney Frank E.
Sternlieb Herschel
Ty Frederick
Ostrager Chong & Flaherty LLP
Polymer Group Inc.
Vanatta Amy B.
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