US3537810A

US3537810A - Process for the carbonization of wool

Info

Publication number: US3537810A
Application number: US539529A
Authority: US
Inventors: Heinz Fleissner; Gerold Fleissner
Original assignee: PATENTDIENST ANST
Current assignee: PATENTDIENST ANST
Priority date: 1965-04-14
Filing date: 1966-04-01
Publication date: 1970-11-03
Anticipated expiration: 1987-11-03
Also published as: GB1133718A; FR1479589A; ES325867A1; BE679351A

Abstract

A device having a plurality of treatment units for carrying out the continuous carbonization of wool, comprising first means for acidifying the wool including first conveying means, comprising sieve drum means subjected to a suction draft wherein the treatment liquid is drawn from the outside to the inside of the drum, extraction means operatively connected behind said first means for extracting acid from the wool, first drying means operatively connected behind said extraction means for drying the wool and effectively subdivided into a drying zone and into a baking zone, removing means operatively subdivided into a drying zone and into a baking zone, removing means operatively connected behind said drying means for removing the carbonized matter from the wool, and neutralizing means forming at least one neutralizing bath for neutralizing the acid remaining within said wool, said neutralizing means being operatively connected behind said removing means.

Description

, Nov. 3,1970 H. FLEISSNER ETAL 3,537,810

PROCESS FOR THE CARBONIZATION OF WOOL 2 Sheets-Sheet 1 Filed April 1. .1966

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United States Patent Office PROCESS FOR THE CARBONIZATION OF WOOL Heinz Fleissner and Gerold Fleissner, Egelsbach, near Frankfurt am Main, Germany, assignors to Anstalt fur Patentdienst, Vaduz, Liechtenstein Filed Apr. 1, 1966, Ser. No. 539,529

Claims priority, application Germany, Apr. 10, 1965,

A 48,926; Oct. 14, 1965, A 50,486 Int. Cl. D06c 7/04 US. Cl. 8-140 14 Claims ABSTRACT OF THE DISCLOSURE The present disclosure is directed to a process and apparatus for the continuous carbonization of wool, preferably in the form of flock, comprising the steps of wetting the wool with an acid solution, thereafter extracting, drying and heating the wool to a baking temperature, subsequently removing carbonized matter from the wool and thereafter neutralizing the acid adhering to the fibers of the wool, at least some of the treatment media used in the aforementioned steps being applied to the wool by means of a suction draft.

The present invention relates to a process and a device for the continuous carbonization of wool, preferably of wool flock, in which process the wool is wetted with acid, preferably with sulphuric acid, extracted, dried and heated to a baking temperature, subsequently opened and/or beaten, and in which process the acid adhering to the wool fibers is then neutralized. The present invention is applicable to various wool processing stages, i.e., to raw wool, to top, to yarn, and to piece goods.

Carbonization is the treatment of the wool with an acid, especially with sulphuric acid, at elevated temperatures, in order to destroy vegetable contaminations such as burrs, shives, cotton and staple fibers, and other cellulosic products so that they can be better removed from the wool.

Known processes for the carbonization of wool consist of the following processing stages:

(1) Immersion of the wool into an acid bath for -30 minutes so that there is suflicient time for the acid to deposit on the cellulosic matter. In general, a 3-6% sulphuric acid solution is used as acid liquor.

(2) Extraction and drying of the wool for the condensation of the acid and for the hydrolysis of the cellulosic matter.

(3) Baking, i.e., heating of the Wool to 100-120 C. for dehydration and carbonization of the cellulosic matter whereby the baking time amounts to approximately minutes.

(4) Breaking up and removal of the charred cellulosic matter by opening or beating the wool.

(5) Neutralization and removal of the acid as well as scouring of the wool in a scouring bath, generally followed by:

(6) Drying of the Wool. This drying process can be omitted if the wool is dyed or finished by a wet treatment afterwards.

For acidifying the wool in flock form, so-called leviathan washing machines are known in which the wool is transported through the acid liquor by means of rakes which immerse into the acid liquor. Since the required residence time in the acid liquor amounts to 15-30 minutes, extremely long and expensive acid baths are required as well as a correspondingly high number of rakes for the transportation of the wool through the acid bath.

For drying and baking the wool, drum dryers or belt dryers are used. For removing the charred cellulosic matter, various units can be used, for example, openers, beating machines, carding machines and the like.

3,537,810 Patented Nov. 3, 1970 For the subsequent neutralization of the loose wool, again leviathan washing machines are used or, in the case of piece goods, the usual roller washing machines are used for acidifying as Well as for neutralizing. For the final drying, again belt or drum dryers, especially sieve drum dryers, are used.

In spite of the use of auxiliary agents, the aforementioned relatively extended treatment times are required for a good Carbonization of the wool in the known devices. Without the use of wetting agents impregnating times of l-2 hours are necessary. By a reduction of the treatment time, especially of the impregnating time, to 15-30 minutes, the turn-out of the material, i.e., the wool quality, could be essentially improved..HoWever, also with these treatment times there are suflicient detrimental effects which cause, in particular, a varying dye affinity and which result in considerable strength losses of the wool fibers.

The present invention has the object to eliminate the aforementioned disadvantages by reducing the treatment times, especially the impregnating time, and the time from acidifying to neutralizing, i.e., the total time during which the acid reacts on the wool.

In accordance With the present invention it has been found that shorter treatment times can be obtained by a more intense mass transfer, e.g., by more intense wetting and quick drying of the wool and of the cellulosic matter in the wool. In accordance With the present invention it is, therefore, proposed to pass the various treatment media through the wool by means of a suction draft since thus the best mass transfer is ensured. In further developing this object of the present invention, it is proposed to use at least one suction drum bath for wetting the Wool.

Surprisingly tests have shown that when using a suction drum bath a wetting time, i.e., an acidifying time, of about seconds is suificient in order to obtain, after squeezing and drying and baking in'sieve drum dryers working with a suction draft, a good carbonization and thus destruction of the cellulosic matter. This extreme reduction of the treatment time is most astonishing. A clear explanation is still missing. The phenomenon might possibly be explained by the fact that large quantities of acid are brought up to the cellulosic matter by the suction draft and that the cellulosic matter is enriched with acid much more rapidly when a sufficiently large amount of acid is brought up than was assumed up to now. Also it has been found that with these short acidifying times, essentially less acid is deposited on the wool. This means considerably smaller strength losses of the wool and lower chemical costs, since less acid and smaller amounts of alkalis for the neutralization are required.

By the use of the known sieve drum dryers for drying and baking, also the drying and baking times could be significantly reduced, e.g., to 3-5 minutes. I

According to another object of the present invention it is proposed to cool the acid bath down to a temperature below 20 C. Preferably the acid bath should have a temperature of 10-l5 C. It has been found that with such low temperatures the Wool combines with much smaller quantities of acid whereas the acid absorption of the cellulosic matter which is to be charred does practically not decrease. The aforementioned advantages apply here to an even greater extent.

According to another object of the present invention it is proposed to pass the wool through a gas or steam atmosphere which is enriched with or consists of neutralizing agents for the neutralization of the acid adhering to the fibers after baking.

In another embodiment of the present invention it is also possible to spray the neutralizing agent onto the wool when the wool enters the neutralizing zone and to maintain a temperature in the neutralizing Zone at which temperature the neutralizing agent is essentially evaporated and volatilized. By the use of the suction draft by means of which the treatment medium is sucked through the wool, according to the present invention, an equal distribution of the medium amongst all wool fibers is effected and thus a completely uniform and good neutralization of the acid adhering to the wool.

Uniform neutralizationis favored in the case of this last-mentioned embodiment of the present invention if the neutralizing zone is provided with a device which ensures a constantly uniform gas concentration of a gaseous neutralizing agent. This device may simply consist of, e.g., a measuring instrument which measures the gas concentration and which controls a regulating valve of a gas feed line according to the respective, preset gas concentration. If a spraying device is provided in the neutralizing zone, the neutralizing liquid is controlled in the same way.

In general, the neutralized chemicals form a white powder which can be easily removed from the wool during the subsequent opening or beating process.

For the continuous carbonization of wool it is suggested to use a device which, according to the present invention, consists of at least one suction drum bath with an extraction device, preferably a squeezing unit connected behind the bowl, of a dryer, preferably a sieve drum dryer which is subdivided into a drying zone and into a baking zone, of an opening and/or beating machine behind which are connected at least one neutralizing bath and preferably a dryer, as well as of conveying elements between the individual treatment devices for the continuous transportation of the wool through the device.

It has been found that, e.g., a device consisting of the following units was particularly expedient and favorable for the carbonization of loose wool:

A sieve drum scouring bowl for wetting the wool. That bowl is filled with cold, chemically neutral fresh water.

A squeezing unit at the end of that bowl for squeezing out the liquid.

A further sieve drum scouring bowl for acidifying the wool, and behind that bowl two pairs of squeeze rollers for obtaining an as high as possible squeezing effect. However, instead of one or two pairs of squeeze rollers also a continuously operating hydro-extractor may be used.

A sieve drum dryer with a predrying chamber, a drying chamber, and a baking chamber and possibly a neutralizing chamber.

Or instead of the neutralizing chamber two sieve drum bowls, one containing a neutralizing liquor, e.g., a soap bath with sodium carbonate, and the second containing chemically neutral water for washing out the residues of the chemicals.

A sieve drum dryer for the final drying of the wool.

In general, it is of advantage if all treatment units with the exception of the opening and/or beating unit, work with conveying elements which are subjected to a suction draft, preferably with sieve drums.

Furthermore, it is of advantage, if the material is extracted as far as possible before the combined drying and baking process takes place, since in the case of a good extraction less acid is deposited on the wool fibers and since detrimental effects of the acid on the wool fibers during the drying and making process are thus reduced. If a particularly gentle treatment of the wool is desired, it is recommended to use a continuous hydroextractor after acidifying.

An essential advantage offered by the sieve drum dryer as compared with a belt dryer is, apart from the better drying capacity, the fact that soiling is much reduced. A pronounced disadvantage of the belt dryer is that it must be stopped after a relatively short period of operation for cleaning.

Tests have shown that the quick soiling of such dryers can be avoided if the fiber fleece is consolidated before or at least when being deposited on the conveyor belt. Since the drying capacity depends solely on the air penetrating the fibrous material, the consolidation of the fibrous material does not mean a capacity decrease as was expected up to now.

In the case of longer treatment paths, i.e., in the case of longer conveyor belts, it has been found advantageous if the fiber fleece is consolidated during the drying process once or several times.

Fiber fly and thus a contamination of the belt dryer can be avoided particularly well if the fiber fleece is held to the conveyor belt by means of a suction draft and if it is consolidated at the same time.

Furthermore, it is of advantage if the fiber fleece is exposed to essentially higher drying temperatures in the predrying zone than in the drying zone proper. The drying temperature in the predrying zone may be so high that the fibers in a dry condition would be damaged by that high temperature. However, by the extraction of the moisture, the temperature in the fiber fleece is essentially lower than the air temperature so that fiber damage does not occur.

In the case of a belt dryer with at least one conveyor belt and one device for circulating the treatment medium, one or several rollers or drums may be correlated to the conveyor belt which rollers or drums consolidate the fiber fleece or which, e.g., press against the fiber fleece.

According to the present invention the treatment chamber is designed in this device as a suction chamber with the suction draft directed downwards for consolidating and holding the fiber fleece onto the conveyor belt and/ or the conveyor belts. The suction draft may, e.g., be formed in such a way that below the lower conveyor belt one or several fans with one-sided air discharge are provided, preferably for each treatment zone, and that the fan chamber is separated from the treatment chamber by a wall (bottom) in which openings are provided which are correlated with the exhaust connections of the fans and which correspond in size to the exhaust connections of the fans. It is of advantage if the bearing surfaces of the conveyor belts are sealed, preferably at the sides in order to prevent the air and the fibers from being sucked off.

If a dryer with several superimposed conveyor belts is used, the dryer may be equipped with a device for reversing and for passing on the fiber fleece from one conveyor belt to the next one. Such a device may consist of an adjustable chute with a roller which is correlated to the conveyor belt below. It is of special advantage if the material is passed on outside of the treatment chamber. In case of such an arrangement the roller serves simultaneously for sealing the intake of the second conveyor belt and/ or of the conveyor belt which is arranged below.

If the dryer is subdivided into several chambers, each chamber may form a treatment zone with varying treatment temperatures. In that case it is advantageous to seal the point of passage of the material and of the conveyor belt from one chamber to the next one by means of a roller which simultaneously serves for consolidating the fiber fleece.

Especially expedient is a device in which, within the predrying zone, sieve drums subjected to a suction draft are used as conveying elements and in which at the point of passage of the fiber fleece from the sieve drums to the subsequent conveyor belt a roller is arranged which presses against the fiber fleece and which consolidates it at the point of passage. The predrying zone or the dryer with sieve drums subjected to a suction draft may also be completely separated from the belt dryer. In that case it is of importance that the fiber fleece is not loosened up when being passed from the sieve drum dryer to the belt dryer, as is the case usually up to now, but that the con solidated state is maintained or produced anew.

Furthermore, it is of advantage if the conveyor belt is covered by a fine wire mesh so that fibers cannot be sucked through the conveyor belt.

The drawings illustrate some embodiments of the present invention.

FIGS. 1a and 1b are partial schematic views illustrating a carbonizing plant according to the present invention; whereby FIG. 1b should be thought of as placed along side FIG. la to illustrate the complete overall installation.

FIG. 2 is a longitudinal cross-sectional view of a drying and baking device according to the present invention;

FIG. 3 is a transverse cross-sectional view of the device according to FIG. 2; and

FIG. 4 is a longitudinal cross-sectional view of a modified embodiment of a drying and baking device according to the present invention.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to FIGS. 1a and lb, material 1 to be carbonized, preferably raw wool, is fed in the installation illustrated in these figures into a suction drum bath. For acidifying the wool the treatment liquor may, e.g., consist of 3-6% sulphuric acid. Other carbonizing agents are hydrochloric acid or aluminum chloride. The bath proper is provided with a floating distance 2 at the intake and with a conventional sieve drum 3 subjected to a suction draft at the delivery end. Along the floating distance the loose wool 1 can spread evenly over the whole working width. The loose wool is then sucked onto the sieve drum 3 as a uniform fleece and is passed on to a pair of squeeze rollers 4 arranged behind the sieve drum 3. Owing to the uniformity of the fleece, acidifying as well as the squeezing effect are extremely uniform.

In the device shown in FIG. la, pumps 5 are arranged within the sieve drum 3 perpendicularly to the drum axis. The pumps 5 convey the sucked off liquid into a duct 6 arranged above the same, in which duct the liquid is led out of the sieve drums 3 at the sides thereof, preferably into an open duct extending laterally along the whole treatment bath which open duct is connected with the treatment bath at the intake and/ or along the entire length of the bath by conventional means. A further bath of that kind is connected behind the first one in the device shown.

The loose wool which has been pre-extracted by a second pair of squeeze rollers 4 is then fed to a sieve drum dryer by means of a conveyor belt 7. The dryer shown consists of a housing 8, which is subdivided by a wall 9 into a treatment chamber provided with sieve drums 10 subjected to a suction draft and into a fan chamber (not shown) with fan wheels (not shown) which are arranged at the end face of the sieve drums. By means of partitions 11 the dryer is subdivided into a drying zone 12 and a baking zone 13. In the drying zone only one sieve drum is shown; however, two or more sieve drums may be used as well. Also in the baking zone the number of sieve drums is not restricted to two sieve drums. The number of sieve drums and the number of bowls depends essentially on the required production capacity. The cellulosic matter in the wool is carbonized in the baking zone 13.

For the removal of the carbonized matter an opener of conventional construction is connected behind the dryer in this embodiment of the invention, which opener consists essentially of a pair of feed rollers 14 and of a spiked drum 15. Instead of the opener also a carding machine, a beating machine, or the like or a combination of such machines may be used.

For the neutralization of the sulphuric acid or of another acid used for carbonization three bowls are provided which essentially are of the same design as the acid bowls, but which are equipped with three sieve drums 3 connected one behind the other instead of with one sieve drum only and in which bowls a floating distance 2 is provided behind each sieve drum 3. A pair of squeeze rollers 4 is provided also in this case at the end of each bowl. The first two bowls may contain an alkaline liquor for neutralizing the acid and the third bowl may be a scouring bowl with a neutral liquor. However, it is also possible that the first bowl contains a neutral liquor and that only the second bowl contains an alkaline liquor for neutralization. The latter combination offers the advantage that part of the acid is washed out in the first bowl and that less acid must be neutralized by means of neutralizing agents which results in savings of the neutralizing agents.

Final drying of the wool is again effected in a sieve drum dryer. Here, as in the case of the first dryer, the suction draft in the sieve drum is interrupted by conventional means at the portion of the sieve drum which is free from material, so that the drying air can only be sucked into the sieve drum through the loose wool and the drying air is completely used for drying in each circulation cycle.

The belt dryer according to FIG. 2 has a housing 8 which is subdivided by a partition 11 into two

treatment chambers

12 and 13. The two

treatment chambers

12 and 13 are separated by a bottom 18 from the appertaining

fan chambers

19 and 29 which are arranged therebelow. The treatment chambers .12 and 13 are subjected to a suction draft by means of bottom 18 and fans 21. The fans 21 thereby suck the air out of the treatment chambers.

The air is passed through loose fibrous material 1 deposited on

conveyor belts

22 and 23. A pair of rollers 17 is arranged at the intake of the device which serves for sealing the intake and simultaneously for consolidating the fiber fleece. Another pair of rollers 17' is provided at the point of passage of material 1 from the treatment chamber 12 to the treatment chamber 13.

A chute 24 is used for passing on and for the simultaneous reversal of material 1 in fleece form. A roller 25 at the intake of the conveyor belt 23 facilitates the formation of the fleece and consolidates the fleece.

FIG. 3 shows the circulation of the air in the dryer according to FIG. 2. In a lateral duct 26 the air sucked out of the

treatment chambers

12 and 13 by the fans 21 flows over a heating device 27 into the

treatment chamber

12 or 13 respectively from above. Air guiding sheets 28 are provided for a better air distribution.

The bearing surfaces of the two

conveyor belts

22 and 23 are sealed by sheets 29 at the sides so that the total quantity of the air must penetrate the material deposited on the conveyor belts.

The drying device according to FIG. 4 consists of a treatment chamber 12 provided with sieve drums 10; with one fan each (not shown) is provided at the end face-of each sieve drum 10 which sucks the air out of the sieve drums. In order to ensure that the air can enter the sieve drum only along that portion which is covered by the material, baflle plates 30 are provided along that portion of the sieve drum 10 which is not covered by material. Owing to the powerful suction draft created in the sieve drums, the material on the sieve drums is only predried and the fleece is consolidated. In the following treatment chamber 13 a conveyor belt 22 is provided as a conveying element. At the point of material passage from the sieve drum 10 to the conveyor belt 22, a roller 31 is arranged which presses onto or against the material and which simultaneously consolidates the fiber fleece. At the same time, that roller seals the point of material passage. Since the fiber fleece, especially if it consists of raw wool and similar materials, is loosened up during drying, another pair of rollers 17' may be provided after a certain drying distance. In general, the suction draft will, how ever, sufiice for holding the fiber fleece safely on a conveyor belt 22. For that reason the pair of rollers 17 is drawn in dashed lines.

Various conventional neutralizing agents may be used in the present invention to neutralize the acid, such as a soda solution, sodium acetate, ammonia or the like.

While we have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and we therefore do not wish to be limited thereto but intend to cover all such 7 changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. A continuous process for the carbonization of wool which comprises wetting the wool with an inorganic acid bath which is effective to carbonize the wool but which does not adversely affect the wool quality, by conveying said wool through said bath on the surface of at least one sieve drum means while drawing the bath through said wool by means of a suction draft, drying the wool by conveying it on the surface of at least one sieve drum means while drawing a heated treatment medium through said wool by means of a suction draft, baking the wool similarly as in said drying stage but at a higher temperature, opening the wool to remove the carbonized matter, neutralizing the acid adhering to the wool fibers by conveying it through an acid-neutralizing bath on the surface of at least one sieve drum means while drawing the bath through said wool by means of a suction draft and finally drying said wool by conveying it on the surface of at least one sieve drum means while drawing a heated treatment medium through said wool by means of a suction draft.

2. The process of claim 1, wherein the inorganic acid bath is selected from the group consisting of sulfuric acid, hydrochloric acid, and aluminum chloride.

3. The process according to claim 1, wherein the step of removing the carbonized matter includes beating the wool.

4. The process according to claim 1, wherein after baking, the neutralization of the acid is effected in a gaseous atmosphere.

5. The process according to claim 1, wherein the step of neutralizing the acid includes spraying the neutralizing agent onto the wool after the wool has entered a neutralization zone.

6. The process according to claim 1, wherein the wool is dryed in a pre-drying zone and in a drying zone, and wherein the fiber fleece is exposed to essentially higher temperatures in the pre-drying zone than in the drying zone.

7. The process of claim 1, wherein the wool is wetted with acid for a period of about 30 seconds.

8. The process of claim 1, wherein the drying and baking period extends for a period of about 3 to 5 minutes.

9. The process of claim 1, wherein the acid bath is a treatment liquor containing about 3 to 6% sulfuric acid.

10. The process of claim 1, wherein a floating Zone is provided in the wetting and neutralizing stages of the process.

11. The process of claim 1, wherein the wetted wool is squeezed to extract at least a portion of the acid bath contained therein.

12. The process according to claim 4, in which the gaseous atmosphere is a steam atmosphere.

13. The process according to claim 5, wherein the wool is wetted in the acid bath at a temperature below 20 C.

14. The process according to claim 13, wherein said temperature is between about 10 to 15 C.

References Cited UNITED STATES PATENTS 3,199,126 8/1965 Chaikin et al. 68158 XR 3,374,646 3/1968 Fleissner 68l58 XR 3,410,119 11/1968 Fleissner 68l58 XR FOREIGN PATENTS 683,080 11/1952 Great Britain.

OTHER REFERENCES Mizell et al.: Practical Improvements in Wool Carbonizing, American Dyestuff Reporter, Jan. 21, 1963, p. 51.

MAYER WEINBLATT, Primary Examiner US. Cl. X.R. 682, 158