Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
1. Field o~ the Invention
This invention relates generally to the processing o~ tex-
tiles and more particularly is directed towards a new and im-
proved method and apparatus ~or removing liquid, such as a scour-
ing solvent, from a running web. This invention relates to
means for controlling the level of mist in a closed chamber such
as a solvent scouring apparatus.
2. Description of the Prior Art ~ :
In my U.S. patent 3,771,952, there are
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shown machines fox scouring textiles on a con~inuous basis
wherein the web is carried first through a wetting stage in
which it is scoured by liquid solvent to remo~e impurities~
Once the scouring operation is finished, ~he web i8 carried
over a suction box to remove some of the scouxing liquid and
thence it is transferred to a drying chamher wherein the remain-
ing solvent in the web is removed. While the method and appara-
tus disclosed in the patent and the co-pending applications
~, produce sa~isfac~ory results it has now been ~ound that the web
may he dried more quickly and with reduced drying facilities if
a greater portion of the liquid is removed rom the web prior
'~o entexing the drying chamber. It has also been found that
~; this drying is enhanced if the amount of the chemical mist with-
''' in the enclosed scouring chamber is kept to a minimum.
,' 15 Accordingly, it is an object of the present invention to
; provide an improved me~hod and asqociated apparatus for reduc-
;; ,ing the amount o~ liquid in a web that has been soaked prior to
delivering the same to a drying stage. Another object of the
invention is to provide an improved method and associated appa-
~ 20 ,ratus for reducing ~he amount of mechaniaal mist distributed
'~ within a closed chamber of a scouring range or the liXe.
;~ Summary o~' the Invention
-~ This invention fea~ures ~he method of removing }iquid en-
~ trained in a running web comprising the steps of applying a
,~ 25 suction to one side of said web while simultaneously applying
~,, a heated and relatively dry gas to the opposite side of said
~,' web. Recirculated liquids and vapors are pasced through batts
"~ of metallic wool in order to reduce mechanical mist within the
" atmosphere of the chamber. This invention also features an ap-
'., 30 paratus for enhancing removal of li~uid from a saturated web,
,comprising a suction box mounted adjacent one face of the run-
ning web and a conduit mounted in closely spaaed parallel rela-
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tion to the suc tion box and on the opposite side of th~ web
with the conduit connected to a source of heated gas. The
conduit is formed with a slot facing opposite the slot of the
suction box whereby the heated gas will be fed under pressure
out through the conduit slot, through the web and drawn into
the slot of the suction box.
srief D~scr~?tion of the Drawin~s
;
Fig. 1 is a fragmentary view in side elevation, somewhat
schematic, of an apparatu~ made according to the invention,
Fig. 2 is a sectional end view of the suction box and ho$
g~s conduit of Fig. 1,
Fig. 3 is an enlarged, detailed, cross-sectional view of
t~e vapor return trap of Fig. 1, and,
Fig. 4 is a sectional ~iow in elevation, somewhat schematic,
of the jet openers and shields made according to the invention.
Detailed Description of the Preferred Embodiment
Referring now to the drawings and to Fig. 1 in particular,
there is illustrated, somewhat schematically, a system made ac-
cording to the invention for carrying out the steps of the in-
vention. As shown, a web 10 either in an open width or ~lat tu-
bular condition is carried by a foraminous conveyor belt 12 first
through a wetting stage wherein the web is soaked as by a liquid
~couring solvent discharyed from one or more spray bars 14 dis-
posed about the upper reach of the belt 12. In practice, the
spray bars 14 are in the for~ of tubes extending transversely
abo~e the conveyor 12 and formed with spaced orifices directed
against an arcuate baf~le 16 which converts the jets from the
nozzles into a continuous sheet 18 of liquid deposited over the
web 10 traveling underneath~
The edges of the web 10 may tend to curl inwardlyl particu-
larly if the web being processed is knit ~aterial. In order to
nsure that the scouring action is directed onto the edges of
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the web a pair of adjustable nozzles 20 is mounted in closely
spaced relation above the belt 12 and web 10 adjacent the edges
thereof. The nozzles 20 are directed outwardly and slightly
downwardly towards the curled web edges as best shown in Fig~ 4.
The nozzles 20 are connected to a recirculating pump 22 which
delivers a continuous flow of scouring liquid under pressure
which is directed against the curled web edges causing them to
uncurl and flatten down against the belt. ThP nozzles 20 are
carried by brackets 23 each engaging a traverse mechanism com-
prised of lead screws 24 and 26 under the control of a crank 28.
Operation of the crank will turn the lead screws causing the
krack~ets ~3 and their nozzles 20 to move in and out from the
- cen~er line of the belt in order to accommodate for webs of dif-
~erent widthsprocessed by the apparatus.
From the scouring stage the conveyor belt 12 carries the web
10 over a suction box 28 adapted to remove a substantial portion
of the liquid contained in the web. The suction box 28 typically
is in the form o~ a tubular conduit having a restricted slot 30
extending substantially full length of the suction box 28 which
i~ disposed transversely under the upper reach of the belt 12.
; Typically the suction box slot 30 is on the order of 3/32" in
width and is connected by a conduit 32 to a separator 34 wherein
most of the liquid state solvent removed from the suction box
is collected. The separator, in turn, is connected by a conduit
36 to a ~acuum pump 38 discharging through a muffler 40 into a
return conduit 42 disposed above the conveyor 12. Using the suc-
tion box only to remove the liquid solvent from the web, approxi-
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mately ~5% ~by weight) of the scouring liquid remains in the web
after it has passed over the vacuum slot. Prior to passing over
the slot the web may contain on the order of three times its
weight in liquid. Insofar as the web must be thoroughly dry be-
~ore it can be removed from the apparatus and because of the cost
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of the solvent, it is desirable to recover vi~tually all of the
solvent, and to dry the web as quickl~ as possible.
In accordance with the p.resent invention, the amount of
liquid removed from the web is substantially increased by direct~
ing a continuous flow of hea~ed and relatively dry gas, prefer-
ably solvent vapors, against the web lO directly opposite the
slot 30 of the vacuum box 28. This measure provides a more posi-
tive drying action on the web since the concen~rated flow of dry
gas through the web and into ~he suction box causes more of the
entrained li~uid in the web to be removed than would occur from
the operation of the suction box alone. In practice, using only
a suction box, the vacuum draws in li~uid from the web as well
as cool, moi6t vapors normally present in the vicinity of the
~ web adjacent the box.
: 15 As best shown in Figs. l and 2, the stream of hot, dry vapor
i9 directed against the web and into the suction box by means
of a distributing tube 44 mounted in closely spaced relation to
the upper face of the web lO and Gonveyor 12 and in directly op-
posite parallel relation to the suction box 28. The tube 44 is
formed with a slot 46 aligned with the suction box slot 30~
:. Typically, the distributing tube slot 46 is on the order of l/2
inch in width to insure that the narrower slot of the suction
box slot 30 is spanned to draw in hot, dry ~apor discharged rom
the tube 44 with a minimum amount of moist, cool vapor.
: 25 ~he tube 44 is connected by a conduit 4J8 to a heater 50 in
,
which solvent vapors from the drying section of the range ar~
heated to an elevated temperature, typically on the order of
270 to 280Fo In any event, hot, dry vapor is pumped under pres-
sure by a heater fan through the conduit 48~ through the ~all
of the range housing and into the distribution tube 44 where it
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. is discharged through the slot 46~
:~ In the preferred embodiment, the tubè 44 is cantilevered from
the side wall of the housing and is formed with a pluràlity of
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internal baffles 52, 5~ and 56 originating at the entrance of
the tube at the side waLl and extending to the slot 46. The
baffles are spaced from one another in parallel relation to
terminate in staygered relation across the slot as a means for
insuring even distribution of the heated vapors delivered there-
through. It will be understood that if the baffles were not
provided, the flow of hea-ted gas would tend to be greater near
the left-hand end of the tube 30 with a reduced flow at the
right-hand end. The right-hand end of the tube 44 terminates
in an end wall 58 while the opposite end of the tube may be
connected to the housing wall by means of bolts 60 passing through
- slots formed in the wall of the range and the wall of a tube
flange. In this fashion, the tube may be raised or lowered in
order to change the clearance between the slot 46 and the web
and belt.
In order to maximize the efficiency of the suction box,
a pair of imperforate tapered curtalns 60 as disclosed in my
U.S. Patents 3,828,587 and 3,922,752 may be employed to mask the
~ - outer ends of the suction box slot 30 not covered by the web 10.
,20 In this fashion, the suction box will draw only through the web
and not through the slot ends that would otherwise be exposed
by a narrow web. The curtains 60, as shown ln the aforementioned
patents are wound on a reefing roller 62 and by rotation thereof ~;
the curtains may be drawn in or extended depending upon the
width of the web being processed.
By passing the web between the distribution tube and
the suction box, more of the solvent entrained in the web is
` removed than by the action of the suction box alone and, in
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practice, the web leaving the area o~ th~ suction box and distri-
bution tube will con~ain perhaus 50% solvent (by weight~ as
opposed to the normal 65% where the suction box only is used.
This means that the dryingi chamber will have to remove less sol-
vent than would otherwise be the case. This reduction in the
amount of solvent in the web, as it is introduced to the drying
chamber, reduces the load on the dryingi chamber so that the size
m~y be reduced or its speed in- .
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creased with an accompanying reduction in the residence time
of the web in the drying chamber.
From the suction box and distribution tube the web( carried
by the belt 12, is transferred onto a ~ynchronized conveyor 64
which is located in the dryin~ chamber and, as shown in my co-
pending applica~ion, may comprise a series of conveyors which
carry the web back and forth through a heated atmosphere which
causes the remaining solvent entrained in the web to be flashed
off. The system essentially is a closed loop arrangement in which
the solvent is continuously recycled and care is taken to prevent
loss of solvent from the system.
Since it is desirable to keep the atmosphere within the cham-
ber, especially beyond the wetting section, as dry as possible
means are provided to reduce the amount of mechanical mist devel-
` 15 oped beyond the wetting section. This is accomplished by means
- of the return conduit 42,in Figs~ 1 and 3. The conduit 42 as
previously indicated,receives the discharge o the vacuum pump
which, when it is fed into the conduit 42, is primarily a mech-
anical mist being highly saturated and containing a large per-
centage of liquid droplets. The mechanical mist is converted
into a more vapor state by passing it through a bed o metallic
~; wool 66 be~ore returning it to the chamber. As best shown in
Fig. 3, the conduit 42 is formed with a slot opening 68 in the
side thereof through whiah the mechanical mist is discharged into
a channel formed by a shed baffle 70 supporting a trough 72 sus~
pended therefrom below the slot 68. The trough is formed with a
V-shaped base 74 and a mid-portion filled with the bed 66 of
metallic wool, preferably stainless steel wool. It will be noted
that the left-hand edge of the trough is spaced from the conduit
42 to form a clearance 76. In practice, the mechanical m1st de-
~; livered from the slot 68 first passe6 down thxough the bed of wool
66 which causes a large portion of~the mist to condense. The con-
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densate passes through the wool and collects in the V-shaped base
where it is drained off at either end and collected in the drain
return system o the apparatus, The mechanical mist is thus con-
verted into a drier condition, being primarily vapor which then
passes out through the clearance 76 and into the chamber.
The amount of mechanical mist is also reduced by means of
shields 80 and 82 (Fig. 4) mounted on the side walls of the range
housing oppositely the uncurling nozzle 20. Each shield is com-
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prised of a holding frame 84 mounted dixectly to the housing wall
0 and supporting a batt 8S of metallic wool, preferably stainless
steel wool. The frame 84 and batt 86 are disposed to extend
a~ove and slightly below the level of the belt 12 and web 10 and
in register with the discharge of the nozzles 20. In this fash-
ion the jets from the nozzles, after uncurling the web edges,
will strike against the batt 86 of metallic wool, effectively
reducin~ the amount of mechanical mist generated. If the jets
were directed against a hard, flat wall, the jets would bounce
against the wall, atomizing the liquid and causing a high level
of mechanical mist to be developed. Further, the jets would
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~ 0 produce a substantial amount of noise as they strike the wall. `-
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By using a batt of metallic wool not only is the noise level
substantially reduced but the action o the wool with the jets,
greatly reduces the amount of mechanical mist developed. The
solvent from nozzles remains mostly liquid and is collected by -~
; the drain system of the apparatus. ~ ~
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