Note: Descriptions are shown in the official language in which they were submitted.
In the processing of many fabrics, particularly knitted
fabrics in either tubular or flat form, many of the significant
commercial finishing techniques involve the application of length-
wise mechanical compressive shrinkage to the fabric by processes
which may be regarded as~asymmetrical, in that one side of the
fabric is acted upon at least somewhat differently than the other
side. By way of example, one of the important commercial processes
for the compressive shrinkage of tubular knitted fabric, the
"Compax" process, involves directing the fabric into a compacting
zone formed in part by feeding and retarding rollers rotating
at slightly different speeds. The fabric is being introduced
into the zone at the speed of the feeding roll and is being decel-
erated in the treating zone to the speed of the retarding roll.
As the fabric passes between these two rollers, it is being acted
upon simultaneously by rollers moving at different surface speeds,
; so that at least one of the rollers is moving relative to the fab-`~ ric. One surface of the fabric thus may become slightly "burnished"
so that it may appear slightly more shiny than the opposite sur-
face. This is referred to as "two sidedness".
Two sidedness resulting from asymmetrical compressive
shrinkage treatment, sometimes herein called burnish compacting
is more pronounced with colored fabrics, and of course may be more
troublesome in connection with fabrics processed in tubular form,
where one side of the fabric tube constitutes the same "surface"
as the other side of the tube (e.g., both the top and the bottom
surfaces of a fabric tube may constitute the outside surface of a
garment).
In some cases, asymmetrical processing of the fabric is
at least partially compensated by treatment of the fabric in two
stages, such that any burnishing action is applied to one surface
in the first stage and to the opposite surface in the second stage.
By appropriately proportioning the amount of compressive shrinkage
effort applied at the respective stations~ it may be possible to
- 1 - ~
substantially balance the surface appearance of the fabric. Never-
theless, even using a two station machine, some two sidedness may
result, either because it is not practical to balance it out
altogether, or because the desired proportioning of effort in
order to achieve balance of appearance may not be consistent with
optimum balance of effort for achieving the desired total compres-
sive shrinkage effort. Moreover, in some cases the fabric itself
(e.g., ribbed fabrics) may be of a nature such that its appearance
can be changed undesirably during compressive shrinkage treatment,
as by reason of the thickness compression of the fabric, as well
as any burnishing action.
In accordance with the invention, two sidedness and other
undesired effects in mechanically compressively shrunk fabric may
be greatly improved by a new moisturizing treatment, in which
significant amounts of moisture are imparted with great uniformity
of distribution to the opposite surfaces of the fabric, following
, compressive shrinkage treatment, after which the fabric is immedi-
ately directed into a Palmer-type dryer, in which the fabric is
; held in a geometrically stabilized condition against the heated
surface of a dryer drum, by means of a porous conveyor blanket.
Upon emergence from the discharge end of the Palmer-type dryer,
the fabric is in a finished condition, with significantly improved
surface appearance, both from the standpoint of two sidedness and/
or thickness compression (as in the case of a ribbed fabric).
Moisture is applied to the opposite sides or surfaces
of the fabric in an extremely finely divided spray mist or fog,
under conditions that reliably avoid the formation of droplets,
which might spot or mark the fabric. The amount of moisture to be
applied to the surface of the fabric is somewhat empirical for
different fabrics, but in any event is greater than that which
could possibly be achieved by either steaming of the fabric or by
natural moisture regain. In this respect, steaming of the fabric
may add approximately two percent or so moisture by weight, whereas
s
natur~al moisture regain with time may add about six percent. In
contrast, in some cases, with light fabrics subjected to substantial
compressive shrinkage treatment, it might be appropriate in the .
process of the invention to add surface moisture constituting up
to fifty percent by weight of the fabric.
The rate of moisture application to the fabric, for a
given speed of travel of the fabric, is set such that the fabric
will have been adequately dried by the time it emerges from the
Palmer-type dryer. The spray mist application is set to be applied
; 10 at a constant rate, and the amount applied to the fabric therefore
will vary as a function of the speed of travel of the fabric
through the misting zone. An operator of the process observes
i the fabric emerging from the Palmer-type dryer, and the process can
be progressively speeded up until the emerging fabric evidences
undesirable two sidedness, after which the processing speed may be
slowed down slightly, so that a greater amount of moisture is
; applied to the fabric as it travels to the misting zone. Expe-
rience with the process indicates that restoration of the desired
surface appearance of the fabric is to a great extent a function
of the amount of moisture applied to the surface of the fabric,
such that, once a constant rate of spray application has been
established, excellent control over the process may be achieved
by simply controlling the speed of travel of the fabric through
the spraying-drying sequence. The spraying and the drying at all
times remain in balance, because whenever the fabric speed is
reduced to enable more moisture to be applied, its speed of passage
through the dryer is correspondingly reduced, and vice versa, so
that the drying effort is at all times consistent with the amount
of moisture application.
An improved apparatus arrangement is provided for the
uniform application of spray mist to the opposite surfaces of a
moving fabric web, so that highly controlled amounts of moisture
may be applied to opposite sides of the fabric, with consistent
reliability, free of condensation spots or the like. It will be
understood, of course, that the opposite "sides" of a tubular
fabric will be the same surface. Thus, wherever reference is
made herein to opposite sides or opposite surfaces of a fabric,
such reference will be understood to mean the outside surface of
a tubular fabric or the two surfaces of an open width fabric, as
the case may be.
....
The fabric is conveyed in a completely tension free
manner between opposed banks of spray nozzles, directed at the
respective opposite surfaces of the fabric. Each bank of nozzles
consists of a series of relatively closely spaced fine-atomizing
spray nozzles extending across the full width of the fabric and
~ arranged to discharge an air-atomized fine mist of moisture on the
;; fabric surface. To accommodate the inevitable starting and stopping
of the process from time to time during otherwise continuous pro-
duction runs, means are provided for muffling the spray discharge
of the nozzles during stoppage of the processing line, so that the
nozzles do not have to be turned off. In this respect, stopping
and starting of the air-atomizing nozzles may be occasioned by
momentary sputtering and discharge of larger-than-desired drop-
lets of moisture, which could otherwise spot the fabric.
For a more complete understanding of the above and other
features a~d advantages of the invention, reference should be made
to the following detailed description illustrating the invention
and to the accompanying drawings.
Fig. 1 is a box flow diagram illustrating the fundamental
steps involved in the process of the invention.
Figs. 2a and 2b constitute a simplified representation
illustrating a processing line for carrying out the process of the
invention.
Fig. 3 is a top plan view illustrating an advantageous
form of apparatus for the application of spray mist to the fabric.
surfaces in the quantities and with a uniformity consistent with
the requirements of the process.
Fig. 4 is a cross sectional view as taken generally on
line 4-4 of Fig. 3.
Figs. 5 and 6 are enlarged, cross sectional views of the
encircled areas A and B of Fig. 4O
Fig. 7 is a cross sectional view as taken generally on
line 7-7 of Fig, 6.
Referring now to the drawings, the schematic flow diagram
of Fig. 1 indicates the basic steps involved in the process of
the invention. First, there is the asymmetrical mechanical com-
; pressive shrinkage procedure which, for the purposes of this appli-
cation, may be referred to as "burnish compacting". The term
"burnish compacting" is indicated to encompass various forms of
compressive shrinkage treatment, whether or not performed in two
or more stages, in which, in any one stage, the fabric is treated
differently on one surface than on the other. Typically, this
results in a rubbing action on one surface of the fabric, giving
a slight polishing or burnishing effect. Commercially significant
examples of burnish compacting procedures are reflected generally
in the Eugene Cohn et al. Canadian Patents No. 640,199, NoO 657,405,
and No. 640,266. Other processes, such as that reflected in the
Walton et al. United States Patent No. 3,869,768, will impart
differential action to the opposite surfaces of a fabric and would
thus constitute burnish compacting within the meaning of that term
as used in this application. In general, the term "burnish com-
pacting" is intended to cover rather broadly processes for the
compressive shrinkage of fabrics, in either tubular or flat form,
and either of knitted or other construction, in which one of the
surfaces of the fabric is affected differently than the other,
either because of differential action in /~he compressive shrinkage
equipment itself, or because of the fabric construction.
The terms "surface moisturizing" as referred to in the
flow diagram of Fig. 1, refers to the application of a fine fog
. .
or mist spray to the surface of the fabric on an extremely finely
divided, highly uniform basis. The term "stabilized drying"
~ refers generally to drying of the moisturized fabric with heat,
; while maintaining the geometric stability of the fabric, as by the
use of a Palmer-type dryer, for example, as distinguished from an
air jet dryer.
~ With reference more particularly to Figo 2, the process
;~ of the invention includes a compactor stage 10 which, in the
specifically illustrated example, may be generally in accordance
with the Eugene Cohn et al. Canadian Patent No. 640,266. To that
` end, the compactor includes a spreader stage 11 for receiving
tubular knitted fabric and distending it laterally to a pre-
determined, uniform width. The thus distended fabric is passed
through a steaming stage 12, and then is discharged directly into
a compacting station 13, consisting of respective feeding and
retarding rollers 14, 15, and a confining shoe 16. The fabric
enters the compacting station substantially at the surface speed
of the feed roller 14. However, as it encounters the retarding
roller 15, at a pressure nip formed by the respective opposed
rollers 14, 15, the retarding roller exerts a superior grip on the
fabric, and its movement is retarded substantially to the speed
of the retarding roller. In the region where the feeding and
retarding rollers are directly opposed, the lower surface, in the
case of the compacting station 13, is slightly burnished by the
slipping action of the feed roller 14.
The fabric F, now partially compacted by the station 13,
enters a second compacting station 17, which likewise consists
of a feed roller 18, retarding roller 19 and confining shoe 20,
in this case oriented upside down with respect to the previous
station 13. The arrangement is such that the burnishing action
of the second station feed roller 18 is applied to the upper sur-
face of the fabric 16, whereas it is applied to the lower surface
in the upstream station 13. In the absence of ideal results,
rarely achieved in practice, the mechanically preshrunk fabric
issuing from the second stage compacting station 17 may have some
degree of two sidedness, meaning that one surface will appear
to be different than the other. The two sidedness effect will,
of course, be more pronouned where the burnish compacting is
performed in a single station machine, as will be readily appre-
ciated. Moreover, the effect, although physically probably no
different, is more noticeable with colored fabrics than with white
fabrics and is more noticeable with darker colors than with
lighter colors.
In general, the burnishing effect resulting from burnish
compacting of a fabric does not appear to result from a fundamental
change in the structure of the fabric, but rather from a temporary
change in its surface characteristics. In time, through normal
use, washing, drying, handling, etc., such two sidedness probably
would disappear. In the meantime, however, it represents a
significant impediment to sale and use of the fabric, where there
is a pronounced two-sided appearance.
In accordance with the present invention, fabric dis-
charged from the burnish compacting stage, is conveyed over a
speed control roller 21, including appropriate photoelectric
detectors, by which the speed of the burnish compacting operation
is controlled automatically, in relation to the speed of the
moisturizing and drying operations to be described, so as to
maintain the fabric in a relaxed condition on the discharge side
of the compactor. This is accomplished by detecting the limits of
a loop L in the fabric, so that the speed of the compacting
operation is increased as the loop diminishes and is decreased as
the loop enlarges.
The roller 21, which may be referred to as the speed
control roll, operates at the basic speed of operation of the line,
including the moisturizing operation and the drying stage, and
this speed is set by the process operator with a suitable variable
s
speed control. Fabric leaving the discharge side of the roll 21passes under a guide roll 22 and into the lower portion of a
moisturizing chamber 23, through an appropriate opening 24 (Figo 4)
provided for that purpose. The fabric then travels in a generally
upward course, at an angle of approximately 30 or 40 through the
chamber. While passing through the moisturizing chamber 23, the
fabric F, which is maintained in a relaxed, tension free condition
and in a relatively quiescent state except for its forward motion,
is sprayed on both surfaces with a fine fog or mist of water.
Immediately upon leaving the spray chamber 23, the moist
fabric is supported and conveyed by a belt 26 of a Palmer-type
dryer 28 (Fig. 2b). The belt passes over guide rollers 25, 27
and carries the fabric into contact with the outer surface of
a large diameter dryer drum 29, heated internally by steam to a
temperature of, typically, about 150 C. In the illustrated
arrangement, the dryer belt 26 is formed of relatively heavy,
stable but porous material and is maintained under suitable tension.
The belt thus presses the surface-moistened fabric firmly against
the outer surface of the heated drum 29, while the belt and the
fabric travel together, along with the rotating drum. After passing
completely around the drum, the belt 26 and fabric 16 pass around
a guide roll 30, and the fabric is then conveyed by the belt to
the rear of the dryer stage, where the fabric is gathered, either
by winding into a finished roll 31 or by means of a suitable fold-
er (not shown). After releasing the treated fabric, the dryer
belt 26 passes about a second drum 32, which serves to drive off
excess residual moisture from the belt, and the belt then returns
back to the entry guide roll 25 to receive further incoming fabric.
As reflected in Figso 3-7, the moisturizing chamber 23
desirably consists of an open top tank 33, advantageously having
side and end walls 34-37 and a bottom wall 38, but preferably
with no top. A drain 39 is provided in the bottom to remove
collected excess moisture. Upper and lower banks of nozzles
-- 8 --
~5
40, 41 are located in the tank, respectively above and below the
path of the fabric 16 through the chamber. The banks of nozzles
each consist of transversely disposed header pipes 43, 44 to which
are physically mounted a series of atomizing nozzles 45, 46, arranged
with flow passages of the nozzles communicating with the interior
of the header pipes 43, 44.
Although the invention is not limited thereto, the spray
nozzles 45, 46 may to advantage be "Sonicore" atomizing nozzles,
as currently made available commercially by Sonic Development
Corp., Upper Saddle River, New Jersey. These nozzles are air-
atomizing water spray nozzles which, according to the manufacturer,
are so designed that atomization of the water is enhanced by a
sonic energy field. Typically, atomizing air is supplied to
the nozzles through the manifold pipes 43, 44, and the nozzles
are supplied individually with water, through individual supply
lines (not shown) each of which may be adjusted by an individual .
regulator valve, such that uniform discharge and atomization of
the water may be achieved across the entire bank of nozzles. In
the illustrated apparatus, transverse nozzle spacing may be on
the order of 7-8 cm, across the working width of the spray chamber
23, which may be slightly greater than the maximum width of fabric
to be accommodated in the processing line.
As reflected in Fig. 4, the upper bank 40 of spray nozzles
is arranged to spray downward and to the rear, at an angle of 45
or so to the horizontal, while the lower nozzle bank is arranged
to project upward and forwardly, at a generally similar angle.
The adjustment of the nozzles, in terms of rate of flow, is
typically such as to apply to the surfaces of the fabric a total
of about two and a half ounces of moisture per square yard of
fabric, when the fabric is advancing through the moisturizing
chamber at a rate of approximately 14 meters per minute. When
the nature of the fabric and/or the extent of the compressive
shrinkage treatment enables satisfactory optimization of the fabric
~$~L2~
appearance with the application of a lesser amount of water, the
advance of the fabric through the moisturizing-drying stages
is speeded up, so that the fabric spends less time passing through
the range of the misting nozzles, in which case correspondingly
less moisture is applied.
A concomitant of speeding up the fabric movement, of course,
is that the fabric spends less time on the dryer drum 28, and
this is in fact desirable since there is less moisture on the
fabric to be driven off. Speeding up or slowing down of the rate
of fabric advance thus forms an ideal technique for control of
the process, once a desirable balance is achieved between the time
rate at which moisture is applied to the fabric and the capacity
of the dryer 28 to remove that moisture. An operator at the dis-
charge end of the dryer can simply inspect the fabric for possible
two sidedness or other correctable conditions, and continue to
increase the rate of advance of the fabric, as long as the fabric
appearance remains within specifications. In some cases it may be
possible to operate the process at speeds up to 36 meters per
minute, using a relatively small Palmer-type dryer, processing
light weight fabric which has been only moderately (eOg., 8%)
compacted. In general, the capacity of the burnish compacting
stage 10 is in all instances well in excess of the capacity of the
dryer, such that there is no problem involved in controlling the
compactor stage to respond appropriately to speed variations in
the moisturizing-drying stage.
In the moisturizing stage, the amounts of moisture
typically applied to the fabric surface are considerably in excess
of those amounts customarily applied to fabrics during conventional
finishing treatments. In all events, the moisture applied is
greater, usually significantly so, than the maximum amount of
moisture that could be imparted by application of steam (about 2%,
by weight) and/or by natural moisture regain with time (about 6%
by weight). Because of the significant amounts of moisture to be
- 10 -
applied, the area in the immediate region of the nozzle banks 40,
41 is laden with finely divided mist or fog, and special care must
be taken to avoid the formation of droplets of moisture condensate
- at locations from which the droplets could fall onto the fabric
and form a water spot. To this end, the lower nozzle bank 41 and
its supporting structure are arranged to be located entirely below
the path of the fabric 16, so that any condensate formations merely
drop to the bottom of the tank. Beneath the upper nozzle bank 40,
there is provided a condensate shield 48, which extends from one
side of the tank to the other and has a V-shaped collecting groove
49 inclined downwardly from the center thereof toward the opposite
side walls 34, 35 of the tank. Any condensate falling from the
nozzle bank 40 is caught by the shield 48 and drains down the in-
clined troughs 49 toward the tank side walls. Immediately adja-
cent to the walls, small gaps 50 are provided, enabling the
collected water to drain down the sides of the tank~ In this
connection, the maximum width capacity of the fabric is somewhat
less than the width~of the tank, and typically corresponds to the
width of the nozzle banks 40, 41, as reflected in Fig. 3, such
that condensate guided off to the sides of the tank does not affect
the fabric. In a similar manner, the front wall 36 of the tank
may be provided with a condensate trough 54 (Fig. 4) above the
entrance opening 24, so that any condensate forming on the inside
front wall of the tank is collected and guided off to the sides.
Although the process and apparatus of the invention are
intended to be substantially continuous, inevitably there are
many occasions that require temporary stoppage of the process line
for short times during normal operations. When such stoppages
occur, it is of course necessary to immediately discontinue the
application of moisture to the fabric surface to avoid excessive
wetness. One way of achieving this is to shut off the supply of
water to the nozzles. However, experience has shown that, whenever
the nozzles are shut off and re-started, there is inherently some
amount of sputtering of the nozzles. This can result in water
spotting of the fabric, which is of course highly undesirable~
Accordingly, instead of shutting off the nozzle banks are muffled,
whereby the nozzles are permitted to continue to discharge, but
the atomized water is immediately trapped and drained away without
contacting the fabric and without creating a misty atmosphere
which could either condense on the fabric or on surfaces of the
moisturizing chamber 23 in a manner to create a potential water
spotting problem.
Both the upper and lower banks 40, 41 of atomizing
nozzles are mounted for pivotal movement as by providing for
limited rotational movement of the manifold pipes 43, 44,as
reflected particularly in Figs. 5 and 6. During a temporary
stoppage in the processing line, the manifold pipes 43, 44 may be
rotated in a direction to tilt the respective banks of nozzles
45, 46 downwardly behind shield plates 48, 51. Mounted on each
of the shield plates is a muffle strip 52, 53 of porous sponge
arranged either to extend in a continuous strip across the working
width of the shield or in individual sections located in alignment
with the respective nozzles 45, 46. The positioning of the sponge
elements 52, 53 is such that, when the nozzle banks are retracted
to the broken line positions shown in Figs. 5 and 6, by rotation
of the manifold pipes 43, 44, the nozzle tips depress the material
of the sponge, permitting adjacent areas of the sponge to deform
around and embrace the orificearea of the nozzleO Accordingly,
as the atomizing nozzles continue to discharge atomized water,
the discharge is emitted directly into the sponge muffle strips
52, 53. The atomized water is thus instantly condensed within the
sponge, as it issues from the nozzle. Water of course accumulates
within the sponge muffle elements 52, 53, but as soon as the
sponges are saturated, the water flows from the bottom of the
sponge, along the lower flanges of the shields 48 9 51 and into
the bottom of the collecting tank 33. When the process is resumed
- 12 -
again, after a temporary stoppage, it is merely necessary to tilt
the nozzle-mounting manifold pipes 43, 44 back to their normal
positions, so that the atomized discharge from the nozzles is
directed at the fabric surface. The described muffle arrangement
also facilitates initial start up of the line, as the nozzle banks
may be activated while in the retracted positions and operated
briefly to clear the lines and nozzles to avoid sputtering on the
fabric itself.
The system of the invention is advantageous in connection
10 with the finish processing of mechanically compacted fabric,
where it is desirable to restore surface characteristics of the
fabric after the compressive shrinkage treatment. The process is
intended for and is useful to greatest advantage in connection
with asymmetrical burnish compacting techniques, such as described
herein, although it also has possible application in other finishing
treatments in which the fabric surface is temporarily affected
(as by crushing, for example).
The invention involves the application to the processed
fabric of significant quantities of surface moisture, in an
20 extremely finely divided, uniformly distributed state, free of
discrete, large droplets or the like, that might cause water
spotting, and in amounts significantly greater than is possible
either through steaming operations or through natural moisture
regain. The fabric, with its surfaces thus substantially moisturized
is then conveyed through a stabilized drying process, during which
the surface moisture is driven from the fabric while the fabric is
s maintained in a geometrically stable condition, as by being confined
between a heated dryer drum and a tensioned conveyor belt. During
the drying procedure, the surface-applied moisture on the fabric
30 is vaporized, driven slowly through the confined fabric and then
released to the atmosphere. During the relatively extended period
in which the fabric is traveling in contact with the heated dryer
drum (e.g., 15-25 seconds at typical processing speeds), the
.r~
natural fibers of the fabric are fully penetrated with moisture~
The resulting effect is to substantially restore the surface
appearance of the fabric, where it has been burnished and/or
crushed, without significantly affecting the mechanical pre-
shrinking imparted to the fabric in the upstream stage of the
process.
One of the important practical features of the new
process is the ease with which it may be monitored and controlled
in a typical plant operation. Generally, a limiting factor is the
capacity of the Palmer-type dryer to drive off moisture applied
during the moisturizing stageO Accordingly, for a given nominal
linear speed of fabric movement (e.g., 14 meters per minute), the
rate of moisture application from the nozzle banks 40, 41 is ini-
tially adjusted so that the nozzles apply as much moisture as
can be removed by the dryer. Since the moisture application is
essentially accomplished on a weight per unit area basis, this
preliminary setup of the line is relatively independent of the
character of the fabric being processed. In a practical embodi-
ment of the processing line of the invention, utilizing a Palmer-
type dryer with a drum of about 1.5 meters dia~eter, a properbalance of moisture application to drying capacity was realized
with an application rate of about 2.5 ounces per square yard.
Having established an appropriate balance between rate
of moisture application and drying capacity, the process may there-
after be governed almost exclusively by simply increasing or de-
creasing the rate of linear movement of the fabric through the
processing line. By speeding up the linear movement of fabric,
the amoun~ of moisture application per unit of area is propor-
tionately decreased, as is the time spent in the dryer phase.
In general, as long as the fabric emerging from the discharge side
of the dryer stage has an appearance of two sidedness or other
surface characteristics sought to be eliminated, the operator can
adjust the process by gradually reducing the rate of linear
- 14 -
,
movement of the fabric until its appearance is within specifications.
By thus slowing down the fabric, more moisture per unit of area
is applied by the nozzle banks 40, 41, and correspondingly more
time is spent on the dryer.
As can be well appreciated, different types of con-
struction of the fabric will require individually different treat-
ment in terms of required levels of moisture application. Likewise,
some fabrics may be compressively preshrunk only to a relatively
small degree (e.g., 8-10%) while others may have substantially
greater compressive shrinkage, all depending on a great variety of
conditions and requirements in the mill. The process of the
invention, however, easily accommodates the range of such variables,
through the simple control of speeding up or slowing down the
linear movement of the fabric through the moisturizing and drying
stages. In all cases, the speed of operation of the compacting
equipment is subservient to the speed of operation of the
moisturizing-drying stages. This is accomplished by sensing the
size of the fabric loop 22, between the compactor stage and the
moisturizer stage, and appropriately increasing or decreasing
the speed of the compactor stage.
; In view of the substantial amounts of moisture applied
to the fabric during the moisturizing stage, it is significant
to maintain the fabric relaxed and quiescent during moisturizing
and to maintain fabric geometry during drying. This is accomplished
through the use of misting type spray nozzles for moisture
application and a Palmer-type dryer for the drying stage. Because
the fabric has been compressively preshrunk longitudinally prior
to moisturizing, it is significant to the process that the moisture
application be in the form of surface application rather than
complete impregnation of the fabric, so that the fabric does not
lose its geometric integrity while it is unsupported. After
the fabric is engaged by the Palmer-type dryer and is geometrically
stabilized, the moisture can fully penetrate the fabric without
- 15 -
adversely affecting the mechanical compacting.
The spray chamber arrangement described herein has been
found to be advantageous for the purposes intended, enabling
significantly high amounts of moisture to be applied to the surface
of the fabric, while avoiding condensation and spotting problems,
and while simultaneously maintaining the fabric in a properly
relaxed and quiescent state. In the illustrated arrangement, the
fabric enters the open top chamber in the lower front portion,
and is guided upwardly, to exit from the chamber in the upper rear
portion thereof. The upwardly inclined path of travel through the
spray chamber enables the nozzle banks to be conveniently and
effectively located both with reference to spray application
effectiveness and with respect to avoidance of condensation and
drip problems. At the same time, the upwardly inclined path of
travel of the fabric is advantageous from the standpoint of
minimizing stress on the fabric which, when it emerges from the
moisturizing zone, is both moist on its surface and laden with the
weight of the moisture, so as to be particularly vulnerable to
longitudinal strains. To this end, in addition, the moisturizing
chamber is closely coupled with the Palmer-type dryer. Indeed,
the exit guide roller for the moisturizing chamber is the entry
belt guide roller to the Palmer-type dryer, so that the fabric
is physically supported immediately upon its emergence from the
moisturizing zone.
The process of the invention is applicable to a wide
variety of fabrics, of both knitted and non-knitted constructions
and of both tubular and non-tubular configuration, provided the
fabric has sufficient natural or other hydrophilic fiber content to
enable it to respond to the application of moisture. The process
is, of course, extremely advantageous in connection with the finish
processing of tubular knitted fabrics, where a relatively high
percentage of burnish compacting may be applied to the fabric in
a first phase of its finish processing and where uniformity of
- 16 -
surface appearance on the top and bottom of the tubular knittedfabric web is of particular significance, inasmuch as the top and
bottom constitute the same surface.
In general, the production capacity of available burnish
compacting equipment is significantly greater than the linear
output capacity of a Palmer-type dryer of practical size and
configuration. Accordingly, overall production efficiencies may
be improved in many instances by performing the burnish compacting
operations separately, rather than in line with the drying
operation. In such cases, the compacted fabric may be folded or
otherwise gathered in a tension free condition at the discharge
end of the compacting equipment. In a separate operation, two or
more webs of compacted fabric may be conveyed simultaneously
through a common apparatus, to carry out the moisturizing and
drying sequence as described herein. Such an arrangement may be
particularly advantageous where the compacted web is relatively
narrow and/or where the moisturizing-drying treatment of the
fabric requires a relatively low linear rate of travel through
the dryer for optimum conditioning.
Thus, the invention includes a process for the finish
treatment of fabrics containing at least some proportion of
hydrophilic fibers, which comprises mechanically compressively
shrinking the fabric longitudinally by an asymmetrical compressive
shrinkage process, supplying the compressively shrunk fabric
to a moisturizing zone and advancing the fabric through said zone,
the improvement characterized by applying surface moisture to the
fabric, during its passage through said zone, in amounts greater
than the potential natural moisture regain of the fabric, and
immediately thereafter directing said fabric through a drying zone
and drying the fabric while maintaining the fabric geometrically
stabilized.
The invention also includes apparatus for carrying out
the process of claim 1, which comprises a burnish compactor,
s
moisturizing means forming a moisturizing zone for the application
of finely divided mist to the surface of the fabric, means for
guiding and advancing said fabric through the moisturizing means
substantially free of lengthwise tension, a Palmer-type dryer
arranged in close coupled relation to said moisturizing means,
said dryer including a heated drum and a continuous conveyor belt,
the improvPment characterized by said moisturizing means including
a bank of finely atomizing moisture-emitting nozzles mounted in
said chamber; means for controllably disabling said nozzles com-
prizing a muffle shield and means for bringing said muffle shieldand said nozzles into positions in which said nozzles discharge
directly into said muffle shield; and said conveyor belt being
: arranged to engage and support the moistened fabric upon its dis-
charge from said moisturizing means.
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