U.S. patent number 3,630,660 [Application Number 04/772,264] was granted by the patent office on 1971-12-28 for process for removal of moisture and/or solvents from textile materials.
This patent grant is currently assigned to Burlington Industries, Inc.. Invention is credited to Frederick C. Wedler.
United States Patent |
3,630,660 |
Wedler |
December 28, 1971 |
PROCESS FOR REMOVAL OF MOISTURE AND/OR SOLVENTS FROM TEXTILE
MATERIALS
Abstract
A process and apparatus for removing water and/or other solvents
from textile materials during the treatment of the same. The
textile material which has been treated by scouring with a solvent
or with a solvent containing a treatment material, or a textile
which has been treated by a solvent media for the application of
chemicals, dyestuffs, or the like, is subjected to vacuum, and if
desired, to a predetermined controlled temperature for a
predetermined controlled time period in order to remove residual
solvent from the textile, and from any desired treating materials.
In the situation where the treating material is a solvent media
with chemicals or dyestuffs, the temperature may be elevated above
that necessary to vaporize the residual solvent so that the
chemicals or dyestuffs may react and be deposited on the textile
material and be affixed thereto. A solvent can be defined as "that
which dissolves," i.e., a medium into which other materials can be
put into solution or suspension to give fluency. Water is the most
generally used solvent, and is treated here in the same context as
the low-boiling hydrocarbon solvents, that is, a solvent to be
recovered.
Inventors: |
Wedler; Frederick C.
(Greensboro, NC) |
Assignee: |
Burlington Industries, Inc.
(Greensboro, NC)
|
Family
ID: |
25094490 |
Appl.
No.: |
04/772,264 |
Filed: |
October 31, 1968 |
Current U.S.
Class: |
8/139; 8/142;
8/139.1 |
Current CPC
Class: |
F26B
13/08 (20130101); F26B 5/04 (20130101); F26B
25/005 (20130101); F26B 13/10 (20130101); F26B
25/006 (20130101); D06B 3/10 (20130101); D06B
2700/09 (20130101) |
Current International
Class: |
D06B
3/00 (20060101); D06B 3/10 (20060101); F26B
13/10 (20060101); F26B 25/00 (20060101); F26B
13/00 (20060101); F26B 13/08 (20060101); F26B
5/04 (20060101); D01c 001/00 () |
Field of
Search: |
;8/139,142,139.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Weinblatt; Mayer
Claims
What is claimed is:
1. A process for the treatment of textile material in web or
continuous length form including removing a liquid solvent media
entrained in the textile material comprising the steps of:
subjecting the textile material to a relatively strong vacuum in an
enclosed zone; controlling the temperature within the enclosed zone
so that the temperature is elevated sufficiently to vaporize the
solvent; removing the textile material from the enclosed zone,
condensing the evaporated solvent removed from the textile
material, collecting the so-condensed liquid and withdrawing it
from the enclosed zone separately from the removal of the textile
material from the enclosed zone.
2. The process of claim 1 wherein the textile material is
continuously moved through the enclosed zone.
3. The process of claim 1 wherein the material is subjected to the
vacuum and temperature for a predetermined length of time
sufficient to essentially dry the textile material.
4. The process of claim 3 wherein the textile material is treated
with said solvent prior to entry into the enclosed zone.
5. The process of claim 4 in which the temperature within the
enclosed zone is elevated above the flash point temperature for the
solvent.
6. The process of claim 3 in which the temperature in the enclosed
zone is elevated by heating means.
7. The process of claim 3 in which the textile material is brought
into contact with a heated surface to elevate the temperature of
the same.
8. The process of claim 4 in which the solvent is a scouring
agent.
9. The process of claim 8 in which the textile material is squeezed
after scouring and prior to entry into the enclosed zone so as to
remove as much of the scouring solvent as possible, the remaining
portion of the scouring solvent being removed in the enclosed
zone.
10. A process as defined in claim 8 wherein the solvent-scouring
agent is selected from the group consisting of perchloroethylene
and trichloroethylene.
Description
The present invention is concerned with certain improvements in the
treating of textile materials, preferably in web form, so that the
material may be continuously treated, although it is contemplated
that the process and apparatus is applicable for a batch
treatment.
In the copending U.S. application Ser. No. 746,972, filed July 23,
1968, of Frederick C. Wedler and Kenneth Y. Wang there is disclosed
a process and apparatus wherein a textile material is degassed
prior to impregnation of the same with a treating agent. By
degassing the textile material prior to treating with a treating
agent, impregnation and penetration of the treating agent is more
effectively and conveniently accomplished. In the copending U.S.
application Ser. No. 746,973, filed July 23, 1968, by Frederick C.
Wedler, a somewhat similar process is disclosed utilizing the
degassing principle, but in a batch treatment of textile material.
The present invention is related to, and is an improvement of the
inventions of the aforementioned applications, but it utilizes a
vacuum not merely to degas the textile material but to vaporize any
moisture such as water and/or solvent in the material after certain
treating operations, so that the textile material emerges from the
vacuum treatment in a substantially dry condition, ready for any
desired subsequent treatment. Additionally, the present invention
contemplates removing, by use of vacuum and temperature, if
desired, the solvent from a system in which the textiles are
treated or materials are applied, such as chemicals or dyestuffs.
Such removal of solvent effectively causes the reaction and
fixation of the applied materials to the textile material, the
textile material still emerging from the treatment in a dry
condition, if desirable.
Heretofore in the textile industry, solvents have been removed from
textile materials by application of steam, hot water, hot air, or
by contact with hot cylinders. While these systems have been
sufficiently rapid and inexpensive to permit use in present
practice, they have not permitted satisfactory complete removal of
the solvent vapor from the treated material or from the treatment
atmosphere. As a minimum, this has resulted in odorous
contamination of the treatment atmosphere and some loss of solvent
on a continuous basis from the material and the atmosphere. More
particularly, it has simply not been possible, through present
solvent removal procedures, to rapidly obtain almost complete
removal and recovery, if desired, of solvent from the treated
material, and of solvent vapor from the treatment atmosphere,
rapidly and effectively, simply for economic recovery and safety,
or to permit further uncontaminated treatment in rapid succession,
or to rapidly follow another treatment and ready the treated
material for final use or delivery.
Removal of solvent from the treatment atmosphere is critically
important when high temperatures are subsequently employed,
sufficient to break down the solvent and form poisonous gases. Such
complete removal of solvent is not possible with conventional
systems that remove both solvent and moisture.
Accordingly, a principal object of the present invention is to
provide an improved process and apparatus for removing moisture
such as water and/or other solvents from textile or other
materials, the process and apparatus contemplating the complete
recovery of the solvent and the substantial drying of the treated
material.
It is another important object to provide an improved process and
apparatus to provide for removal of solvent vapor from the
treatment atmosphere in a textile, or other material, treating
step.
Ancillary to the preceding objects, it is a further object of the
present invention to provide a process and an apparatus which will
not only remove and recover solvents by utilizing a vacuum and
controlled temperatures, but will also assist in causing improved
reaction and fixation of chemicals or dyestuffs to the textile
material when such chemicals or dyestuffs are utilized in a solvent
media.
Another important object of the present invention is to provide an
improved process and apparatus for removal and recovery of solvents
from textile material and from the atmosphere in the treating zone
in a minimum of time at any selected temperatures in a vacuum, the
temperature being either reduced, ambient or elevated, and the
textile material emerging substantially dry whereby further
treatment may be immediately accomplished if desired.
While the process of the present invention is capable of use in the
batch treatment of various types of textile materials, the process
will be described in relationship to an embodiment for the removal
of moisture and/or solvents from the textile material by a
continuous treatment of the same, either following a treatment
involving some application of solvent or moisture to the textile,
or in a treatment involving the deposition of material on the
textile from solvent media, or as a prelude to a subsequent
treatment step requiring solvent free material and/or atmosphere.
Additionally, the invention will be described in the treatment of
textile material in the form of webs or continuous lengths of
materials such as woven, nonwoven, knitted- or stitch-bonded
fabrics, multifilament yarns, yarn bundles, silver, roving, tow, or
the like, but it will be appreciated that materials other than the
foregoing "conventional" textiles, such as paper, leather, plastic
and the like, may utilize the process and apparatus described
herein.
Broadly stated, the present invention involves the passing of a
textile or other weblike or continuous yarnlike material through a
vacuum chamber, the material having moisture and/or a residual
solvent therein prior to entry into the chamber. For example, the
textile material may have been scoured in a solvent scouring liquid
or it may have had a solvent media comprising a solvent and a
chemical or dyestuff or the like applied thereto. By controlling
the vacuum within the chamber, and by controlling the temperature,
if desired, within the chamber, as well as the length of time for
the textile or other material to pass through the chamber, all or
most of the residual solvent may be removed and recovered for
reuse, both from the material, and from the surrounding atmosphere.
That is, it is necessary first to remove the solvent from the
treated substrate, and second to remove solvent vapor from the
treatment chamber to a point where it can be condensed and
recovered.
Additionally, control of the heat within the chamber can be such
that it will cause reaction and fixation of any chemicals or
dyestuffs on the textile material passed through the chamber
simultaneously with the removal of the solvents. By utilizing a
vacuum within the chamber, the temperature for causing flashing or
vaporization of the solvents can be materially reduced as well as
the time for removing such solvents from the textile material. The
advantages of this relationship will be appreciated from table
I.
TABLE I
Boiling Points of Chlorinated Solvents at Reduced Pressure
Tabularized below are the boiling points of perchloroethylene,
trichloroethylene, and water at various reduced pressures, both in
terms of absolute pressure and vacuum applied. Temperature of the
boiling point related to each pressure is given in both Fahrenheit
and Centigrade. ##SPC1##
It will be obvious from table I that as the atmospheric pressure is
reduced, that the temperature for vaporization of the solvents is
also reduced as is the time for vaporization. After the solvent
removed from the textile material has been vaporized, the solvent
in vapor form is condensed and separately removed from the chamber
so that it can be recovered and reused for treatment of other
textile material. This effect can of course be accentuated where
desired, by increase of the temperature of any given pressure to
accelerate vaporization. Similarly, great care can be exercised by
reduced temperature and a slower rate of vaporization, if
desired.
The foregoing objects and advantages of the present invention and a
more detailed description of the same will be made by reference to
the accompanying specification, claims and drawings in which:
FIG. 1 illustrates a diagrammatic vertical sectional view of an
improved apparatus for accomplishing the process of the present
invention, the same utilizing nip rolls for padding the textile
material and sealing for entry to the vacuum chamber;
FIG. 2 is a diagrammatic vertical sectional view similar to FIG. 1
but providing a separate vacuum seal for the inlet to the vacuum
chamber, the material passing through a pair of nip rolls for
padding or applying the solvent media prior to passing through the
vacuum seal;
FIG. 3 illustrates a vertical sectional view through a further
modified form of the apparatus of the present invention; the
textile material passing through the apparatus in a generally
horizontal direction; and
FIG. 4 is a diagrammatic vertical sectional view of a still further
modified form of the apparatus, the view illustrating the use of
the vacuum chamber with a solvent scouring device.
Referring now to the drawings wherein like character and reference
numerals represent like or similar parts and in particular to FIG.
1, there is illustrated an elongated boxlike structure 10 defining
a vacuum chamber 12. The rigid boxlike structure 10 may be made of
stainless steel or other suitable material and must be capable of
withstanding either a partial vacuum or a full vacuum.
A pair of rubber-sealing rollers 14 provide a seal for an inlet
opening 16 of the chamber 12, the textile material T passing into
the chamber 12 through the nip of the rollers 14. The nip of the
rollers 14 is filled with a solvent media 18 containing a solvent
and a chemical or dyestuff and this is applied by padding to the
textile material T as it is passed through the rollers into the
chamber. Of course, a suitable motor (not shown) is utilized to
drive the rollers 14 in the direction shown by the arrows A.
Outlet opening 20 for the chamber 12 is provided with a suitable
vacuum seal 22 through which the textile material T passes out of
the chamber 12. Within chamber 12 there is provided means 24 for
heating the chamber 12, the means being infrared, dielectric,
radiant, or other types of heaters. Suitable control means (not
shown) are provided for the heater means 24 so that the heat within
the chamber can be controlled to a desired temperature for a
particular treatment. At the lower end of the chamber 12, a
plurality of cooling coils are provided, the cooling coils 26
receiving a coolant through a conduit 28 from a suitable condenser.
The purpose of the cooling coils 26 is to condense the solvent
vapor when the same contacts the coils, the solvent vapor being
condensed to a liquid and withdrawn from the chamber 24 by a vacuum
pump 30 through a conduit 29 and then discharged into a tank 32
where it may be reclaimed for reuse. This apparatus is to be
treated as illustrative only however, as the solvent vapor
recovered could easily be condensed elsewhere, preferably at a
point removed from the vacuum treatment chamber 10.
The apparatus of FIG. 2 is substantially identical to that of FIG.
1 except that the inlet opening 16' is provided with a vacuum seal
22' similar to the outlet vacuum seal 22. In the FIG. 2
environment, the pair of padder rolls 14' for applying the solvent
media 18 are located immediately adjacent the vacuum seal 22' but
do not in themselves provide the inlet seal as do the padder rolls
14.
In the apparatus disclosed in FIG. 3, the rigid boxlike structure
10' has a substantially horizontally extending vacuum chamber 12' .
An inlet opening 16, which is identical to the opening 16 of FIG.
1, is provided at one end of the structure 10' in the top wall
thereof. The opening 16 has rubber-sealing rollers 14 associated
therewith which act not only as a means for padding the textile
material with the solvent media 18 but also as a vacuum seal for
the inlet opening 16. At the opposite end of the structure 10' , in
an end wall of the same, there is provided an exit vacuum seal 22
for the outlet opening 20.
The bottom wall of the tank 10' is sloped as indicated at 40 and
the wall is provided on the interior thereof with a plurality of
coolant coils 26 supplied with coolant through the conduit 28 for
the purpose of condensing the vaporized solvent, the same draining
through the discharge conduit 29 and drawn therethrough by the
vacuum pump 30 for reclaiming.
The chamber 12' of the boxlike structure 10' differs in that the
textile material is fed in series over a plurality of rollers
generally designated at 42, the upper rollers of cylinders 44 being
hollow and arranged to receive steam or hot water within the same
for the purpose of heating the same. As shown in the drawing, an
inlet steam conduit 46 extending from a suitable steam generator
(not shown) is provided for applying the steam or hot water to the
upper rollers, the conduit 46 being connected with a manifold 48
leading individually to and supplying the rollers with the
steam.
In each of the apparatus disclosed in FIGS. 1 through 3, the
textile material passes into a vacuum chamber with a solvent media
thereon and then continuously passes from the chamber in a
completely dry state with the solvent of the solvent media being
vaporized from the chamber and then being condensed and withdrawn
therefrom in liquid form for reuse. By controlling the heat, the
chemicals or dyestuffs of the solvent media will react and be fixed
to the textile material T. Of course, the temperature must be
elevated at least to a controlled degree sufficient to cause
vaporization of the solvent at the particular vacuum applied.
However, this temperature is considerably lower than the
temperature necessary for vaporization at atmospheric pressure. As
will now be obvious, when the textile material is discharged from
the vacuum chambers, it will have all of the solvent removed, the
solvent being recovered and the textile material being dry and
ready for any subsequent treatment.
Referring now to FIG. 4, there is disclosed a further modification
of the present invention wherein a scouring tank 50 of the
conventional type is used to scour the textile material T' prior to
its entry into a vacuum chamber 52 of the boxlike structure 54. It
will be noted that the scouring tank 50 is provided with a series
of baths B, B' and B" , the baths being a scouring solution
including a solvent. As will be appreciated by those skilled in the
art, the bath B has the strongest solution therein, the other baths
B' and B" receiving the overflow respectively from the adjacent
bath.
Between the vacuum chamber 52 and the interior of the tank 50 there
is an inlet vacuum seal 56 through which a textile material T
passes as it leaves the tank 50 and enters the chamber 52. Just
prior to passing through the seal 56, the textile material T goes
through a pair of pressure rolls 58 which squeeze excess scouring
solution from the same, the solution dropping into the bath B. The
heaters 24 within the vacuum chamber 52 vaporize any solvent left
in the textile material T and by the time the textile material is
discharged from the exit vacuum seal 60, it will be dry with all
solvent having been removed by vaporization of the same, the
solvent itself being reclaimed by condensing on the coils 26 and
withdrawing from the chamber 52 through a line 62 to a vacuum pump
and reservoir (not shown). Understanding of the invention should
not be limited to the drawing embodiments shown, since, as
explained above, the vacuum treatment can either precede or follow
another treatment step, or the treatment can take place as an
integral part of the vacuum removal step, by deposition of
material, curing, etc. A desirable embodiment would be utilization
of the invention following conventional steam solvent flash off.
Typically, this leaves 0.5-1 percent residual solvent, in a fairly
rapid and economic process. Further solvent recovery is of course
impossible with the conventional steam system. Such a procedure
could be followed by the device 10 according to the drawings, or
other modification, and realize substantially complete solvent
removal/recovery.
While it will be appreciated that the process of the present
invention is capable of use with a partial vacuum up to a full
vacuum for removal and recovering of solvents, it has been found
that the best range for vacuum is between 14 and 29.9 inches of
mercury. In this connection, table I above represents a
relationship between the flash point of different solvents at
atmospheric pressure, and various levels of vacuum. This should be
considered as illustrative, and not limiting on the invention.
* * * * *