US3518847A

US3518847A - Continuous processing of flexible materials

Info

Publication number: US3518847A
Application number: US636232A
Authority: US
Inventors: Herward Duis
Original assignee: Joh Kleinewefers Soehne KG
Current assignee: Joh Kleinewefers Soehne KG
Priority date: 1966-02-18
Filing date: 1967-04-14
Publication date: 1970-07-07
Anticipated expiration: 1987-07-07
Also published as: DE1610994A1; CH478599A; GB1118527A

Description

' July 7 1970 H. DUIS 3,518,847

CONTINUOUS PROCESSING OF FLEXIBLE MATERIALS I Filed April 14, 1967 WVENTO HERWARD DLHS United States Patent 3,518,847 CONTINUOUS PROCESSING OF FLEXIBLE MATERIALS Her-ward Duis, Krefeld-Urdingen, Germany, assignor to Job. Kleinewefers Sons, Krefeld, Germany, a corporation of Germany Filed Apr. 14, 1967, Ser. No. 636,232 Claims priority, application Germany, Feb. 18, 1966, K 58,483 Int. Cl. D06f 39/10 US. Cl. 68-48 2 Claims ABSTRACT OF THE DISCLOSURE An apparatus useful for the continuous processing of flexible materials such as cotton textiles which comprises a pressure chamber capable of holding a treating fluid at conditions in excess of 100 degrees C. and at a pressure above 1 atmosphere, wherein an inlet permits introduction of the flexible material into the chamber below the level of the fluid, and means are employed to convey the material through the chamber and out of the chamber continuously while maintaining the flexible material below the level of the fluid in the chamber. The apparatus additionally contains recirculating means for withdrawing the fluid from the chamber, filtering the fluid and recharging it back to the chamber while simultaneously supplying additional fluid to maintain the Volume at any given level in the chamber.

BACKGROUND OF THE INVENTION Flexible materials such as textiles are often treated with chemicals. A primary example of such chemical treatment, illustrative of the nature of the present invention, is the process of bucking and/ or bleaching textiles such as cotton. The bucking process involves a method whereby cotton is freed of still adhering hull and impurities, while the fibre is also made more receptive to the actual bleaching process. Bleaching, of course, is a process to whiten the flexible material. Other natural and synthetic flexible materials such as rubber, nylon, Wool, etc. are also chemically treated during manufacture.

These processes, and others common to the industry, have been carried out in high-pressure containers. In some instances, more than one operation is carried out simultaneously in a single chamber, while in other instances several succeeding chambers provide for a series of successive operations on the flexible material.

If the processes of bucking and bleaching of cotton is accomplished in separate pressure containers, a disadvantage is encountered when the processes are run continuously, in that the bucking (and the dissolving of the hull) takes substantially longer time than does the bleaching step. This difference in time results in the necessity that the separate steps be performed at different speeds, or that the longer bucking steps be repeated two or more times. An alternative proposal to construct a substantially larger pressure container to increase the residence time is uneconomical because of the substantially greater capital investment which simultaneously limits any use of this equipment for more than this single purpose.

A recently developed theory to explain the bucking process, and its inherent delay, is based upon the fact that the cotton material enters the pressure at a substantially lower temperature than that maintained inside the chamber. Upon enry, the fabric is immediately subjected to steam condensation which causes a thinning or dilution of the surface liquids, thereby reducing the con- 3,518,847 Patented July 7, 1970 centration of the reactant and causing a slow down in the rate of reaction. This dilution effect additionally causes the use of substantially greater quantities of liquids because of their reduced effectiveness, and use of regenerating equipment to restore the reactants is costly and time consuming.

Accordingly, it is an object of this invention to provide an apparatus for treating flexible materials with chemicals in a most efficient manner.

A more particular object of this invention is to provide an apparatus useful for the process of bucking and/or bleaching of textiles such as cotton.

A specific object of this invention is to provide apparatus which is suitable for continuous bucking and leaching of cotton in two successive stages, wherein there exists no substantial difference in residence time between the two stages.

Other objects will become apparent to those skilled in the art upon a careful reading of the description of the invention provided herewith.

It has been found that the objects of this invention may be accomplished in the following manner. A process for treating flexible materials has been discovered which comprises the steps of passing a flexible material through a chamber containing a body of treating fluid maintained at a suitable temperature and pressure, wherein the material enters the chamber at a point below the level of the fluid therein and is passed through the chamber to ac complish the treatment without permitting the material to rise above the fluid level. The process is further improved by the simultaneous withdrawal of a portion of the treating fluid, filtering this withdrawn portion and returning the filtered fluid to the chamber while adding suflicient additional fluid to maintain the level of the fluid above the textile. Other embodiments and modifications are described hereinafter.

It has also been discovered that the process of treating flexible materials in a continuous manner may be effected by the use of an apparatus comprising a pressure chamber suitable for holding a body of fluid and containing means for maintaining the temperature of the fluid at certain temperature and pressure conditions which may be decided upon depending upon the treatment process. The apparatus further contains an inlet for introducing the flexible material, conveying means for conveying the material through the chamber and outlet means for withdrawing the material from the chamber. The apparatus still further contains means for withdrawing a portion of the fluid, filtering this portion and recharging the portion back into the chamber. Finally, the apparatus contains supply means for adding sufficient fluid to the chamber to maintain a constant volume within the chamber, thereby compensating for losses of fluid occasioned by either the filtration step or the removal of the flexible material.

The invention will be further described by Way of example with reference to the accompanying drawings, in which the figure schematically illustrates the apparatus and process of this invention in a specific embodiment.

With reference to the figure, in a vat type pressure vessel or chamber 1, the pressure tight inlet 2 for leading the flexible material 3 through the chamber is installed in the middle of the vat, or in a lower part of the vat, and the liquid level 4 is maintained sufficiently high with respect to the chamber so that the path of the flexible material in the chamber does not rise above this liquid level. The flexible material 3, after being introduced into the chamber 1 by the inlet 2, is conveyed through the body of the fluid contained in the chamber 1 by means of conveying means such as guide rollers 5 which regulate the length of passage of the flexible material. The guiding or conveying means transfers the flexible material to an outlet 6 which withdraws the flexible material from the chamber. By a steam supply 18, the necessary pressure over atmospheric pressure (and a resulting temperature over 100 degrees C.) can be maintained. To optimize the efficiencies of the heat supplied by the steam, it is sometimes desirable to pre-heat the fluid (not shown). It is also possible to maintain the temperature of the body of the fluid in the chamber 1 by means of a heating coil or heat exchanger 7 which is positioned in the interior of the chamber. By installation of the heat exchanger 7 within the pressure chamber 1 in a position eccentric to the center of the chamber, forced convection and a better heat performance is achieved.

Since the normal operation of chemical treatment of flexible materials may and oftentimes does involve production of impurities or byproducts, which are undesirable, an embodiment of this invention is provided to remove these undesirable materials. Referring again to the figure, a conduit 8 is attached to the chamber 1 to permit flow of the fluid into the cleaning apparatus 9, which in this instance, is arranged as a pressure vessel, whereby the fluid is filtered by passage through a filter 10, and from there is returned to the chamber 1 by means of conduit v11 through a circulating pump 12. The cleaning apparatus 9 is provided with an easily exchangeable filter 10, whereby a use of a quick-opening valve 13 permits the removal and cleaning of the filters 10.

In addition, the flexible material 31 passing through the chamber 1 oftentimes picks up a certain amount of the processing fluid, so that this fluid has to be replaced, in an ideally continuous manner. This may be done as shown in the figure by the addition of more fluid through a pressure pump 16 over a check valve 17. The pump is automatically regulated by a liquid level regulator 14 over an amplifying device 15.

The use of the apparatus described in the figure in a specific process whereby cotton textile is subjected to the bucking process demonstrates the efficiencies of the present invention. Due to the fact that the cotton fabric did not contact the steam atmosphere supplying the temperature and pressure conditions, but rather, was maintained below the liquid surface, the cotton was immediately heated to a very high temperature approximating that of the temperature of the fluid in the chamber. The cotton material was passed through the inlet and conveyed through the body of the solution, where upon it was withdrawn from the chamber through the outlet. Simultaneously with this bucking treatment, a portion of the treating fluid was continuously removed from the chamber and passed through the filter, thereby removing impurities which were caused by dissolving the detached hull and fibres. -In one specific instance, operation of the bucking process using the apparatus of this invention resulted in a reduction of the time necessary to satisfactorily treat the material from an average residence time at the particular rate of fabric travel of three minutes down to one-half minute or less. This reduction time provided many advantages to the production of cotton textiles since an efficient and rapid removal of fibres and hulls from the cotton was effected without subjecting the cotton to substantially high temperatures for any considerable length of time. In addition, the rate of bucking was sulficiently high so as to permit a subsequent bleach.- ing process to be effected without any variations in the rate of travel of the textile material. Prior to this time, such an accomplishment was not possible.

Due to the versatility of the present apparatus, it is possible to utilize this same apparatus without modification for a wide variety of other chemical treating operations employed in the manufacture of flexible materials. For example, this same apparatus described hereinabove was employed to bleach a cotton fabric of the type treated in the bucking process operation described above. The

versatility of the apparatus was proved by these experiments in that a substantial and costly problem of chlorine gas escape was obviated. Normally, in the cotton bleaching process, the use of chlorine dioxide has not been used, even though this material is relatively inexpensive, because of the severe problems of chlorine gas escape when the bleached textile is removed from the treating chamber. Furthermore, substantial corrosion if even the most resistant metals is found when the chlorine dioxide is allowed to vaporize in a steam atmosphere to form chlorine gas.

In the operation of the present apparatus, however, these problems were obviated in a satisfactory manner. In the specific operation of the present apparatus for bleaching cotton textiles, the apparatus as described in the figure was again employed. The chamber 1 was completely filled with the treating buid so that the liquid level 4 was at the very top of the chamber 1. The cotton fabric 3 to be bleached was again introduced through the inlet 2 and was conveyed through the fluid by a means of a conveying means 5 to an outlet 6 wherein the bleached material was withdrawn. The sole source of heat for this operation was the heat exchanger 7, since the stream inlet 18 was closed off and not in operation. As was described in the bucking process example, the fluid was withdrawn through the conduit 8 through the filtering device 9, wherein the fluid was filtered in the filter 10 and returned through conduit 11 by means of pump 12 to the chamber 1. The pressure pump 16 through check valve 17 was modified by adjusting the liquid level regulator 14 to provide a full chamber at all times. Thus there was no steam atmosphere present in the chamber and the formation of chlorine gas from the liquid solution of chlorine dioxide was prevented. As the material 3 was withdrawn through the outlet 6, evolution of the chlorine gas caused by evaporation of entrained aqueous chlorine dioxide was prevented by merely running the textile 3 through a canal (not shown) wherein water was sprayed to cool the textile and dissolve the chlorine prior to its evaporation.

The filter 10 contained within the pressurized filter 9 may be cleaned by removal from the pressurized filter 9. A hinge 30 is provided on one end of the pressurized filter 9 to permit that end to pivot about said hinge 30. Latch 32 insures that the filter is properly closed during operation. Handle 34 is provided to permit access to the filter 10.

Thus it can be seen that the instant apparatus is admirably suitable for use in a substantial number of processes wherein flexible materials are treated with chemical additives. The skilled worked will find many modifications and variations of the process which will be suitably adapted to his particular needs without departing from the spirit of the invention.

Having thus described the invention herein, what is claimed is:

1. Apparatus useful for continuous chemical treatment of flexible materials comprising in combination: a pressure chamber suitable for holding a body of fluid with means for maintaining the temperature of said fluid in excess of degrees C. at a pressure in excess of 1 atmosphere; an inlet for introducing the flexible material into the chamber; conveying means for conveying said material through the chamber from said inlet; an outlet for withdrawing said material from said conveying means to a point outside the chamber; recirculating means including a pressurized filter for withdrawing a portion of the fluid from said chamber, filtering said portion and recharging said filtered portion back into said chamber; supply means for adding sufficient fluid to said chamber to maintain a volume of fluid within said chamber above the highest point of travel of said flexible material, said pressurized filter being equipped with shutoff valve means to stop flow of fluid into said filter, and said pressurized filter containing means for withdrawing the filter portion of said pressurized filter for cleaning.

2. The apparatus of claim 1 wherein said supply means 5 comprises an inlet valve attached to and controlled by a pressure pump which is activated by a liquid level regulator adjusted to maintain a volume of said fluid within said chamber above the highest point of travel of said flexible material.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 6/1956 France.

WILLIAM 1. PRICE, Primary Examiner US. Cl. X.R.