US2712977A

US2712977A - Method and apparatus for treating a tow of filaments or threads in a limited space

Info

Publication number: US2712977A
Application number: US295437A
Authority: US
Inventors: Keggin James Fargher
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1951-09-26
Filing date: 1952-06-25
Publication date: 1955-07-12
Anticipated expiration: 1972-07-12
Also published as: NL82434C; CH312133A; BE513202A; NL83273C; DE1040176B; FR1060977A; BE466790A; NL82431C; NL71136C

Description

July 12, 1955 I J. F. KEGGIN 2,712,977

METHOD AND APPARATUS FOR TREATING A Tow OF FILAMENTS 0R THREADS IN A LIMITED SPACE Filed June 25, 1952 INVENTORI J,a mes a ar-$1 12;

BYM

ATTOR NEYS.

United States Patent fiice 2,712,937 Patented July 12, 1955 METHQD AND APPARATUS F'QR TREATING A TGW F FEAM'ENTS 0R THREADS IN A LIM- ITED SPACE James Fargher Keggiu, Seamill, Scotland, assignor to 1mperiai Chemical Industries Limited, a corporation of Great Britain Application June 25, 1952 Serial No. 295,437

Claims priority, application Great Britain September 26, 1951 5 Claims. (8i. 8-1512) The present invention relates to a method of and apparatus for treating a tow of filaments or threads in a limited space and is particularly concerned with a method of and apparatus for treating in non-tensioned condition a continuous tow of artificial filamentary prodportion substantially wider than the narrowest part of L the aforementioned tubular structure, arranging that the necessary length of the upper surface of the said wider tubular structure is at a lower level than the overflow level of the treating liquid and that the speed of the treating liquid through said tubular structures and the inclination upwards in the direction of flow of said upper surface are such that the desired quantity of tow collects against the said upper surface and that the portion of the tow withdrawn from out of the treating liquid at the exit end of the broader tubular structure has remained in the treating liquid for the desired period of time.

It has now been found that it may often be desirable additionally to control the speed of liquid flow in the wider tube and such control is an object of the present invention and is accomplished by preventing a portion of the liquid flowing through the tubular structure of narrower bore from passing through the full length of the tubular structure of wider diameter.

According to the present invention the method of treating a continuous tow of filamentary products in a non-tensioned condition with a treating liquid having a specific gravity greater than the specific gravity of the tow comprising introducing a tow by means of a current of said treating liquid through a tubular structure portion leading to a tubular structure portion substantially wider than the narrowest part of the aforementioned tubular structure, arranging that the necessary length I of the upper surface of the said wider tubular structure is at a lower level than the overflow level of the treating liquid and that the speed of the treating liquid through said tubular structures and the inclination upwards in the direction of flow of said tubular structure are such that the desired quantity of tow collects against the said upper surface and that the portion of the tow withdrawn from out of the treating liquid at the exit end of the broader tubular structure has remained in the treating liquid for the desired period of time is characterised in that a portion of said current of treating liquid is withdrawn from a region at least near to the inlet end of the broader tubular structure.

Preferably the liquid-fibre system in the broader tubular structure is agitated to ensure that there is improved contact between the liquor and the tow, that the liquor is continually changing round the tow in the broader tubular structure, and that any tendency of the portion of the tow in contact with the upper surface of the tubular structure of wider diameter to adhere to said surface is prevented. A further object of the present invention is to provide improved contact between the liquor and the tow. The agitation can be effected by for instance a stream of air bubbles which are caused to enter the broader tubular structure in a region at least near the inlet end.

Apparatus in accordance with the present invention for treating in a non-tensioned condition a continuous tow of filamentary products with a treating liquid having a specific gravity greater than the specific gravity of the tow comprising in combination a constant level feed cone and tubular structure portion leading to a tubular structure portion substantially wider than the narrowest part of the aforementioned tubular structure and the upper surface of which is of desired length and of desired inclination and the exit end of which is at a higher level than the desired length of said upper surface is characterised in that there is an outlet for the treating liquid at least near to the inlet end of the broader tubular structure.

Preferably the apparatus is also provided with an inlet for compressed air at least near to the inlet end of the broader tubular structure and so designed as to give intermittent relatively large air bubbles.

The method of the present invention has been found particularly advantageous for the insolubilisation of continuous travelling tows of artificial filamentary prodnets of protein with acidified concentrated saline solutions containing formaldehyde and of the kind which are of higher specific gravity than said tow.

As in the method of Patent No. 642,359 the treating liquid and the tow pass through the narrower bore of the tubular structure at relatively high speed. The speed of the liquid here which is controlled by the head or difference in level of the liquid at the entrance to the narrower tube and the exit of the wider tube or alternatively the pumping pressure, must be at least as great as the tow at this point. On entering the wider tube the tow folds irregularly and forms a loose column of fibre which moves slowly up the tube against the upper surface. This speed of travel in the wider tube is controlled to some extent by the speed of liquid flow in the wider tube which depends on the relative bores of the narrower and wider tubes and the initial speed of the tow and also in contradistinction to the method of said patent on the amount of treating liquid which is bled off at the outlet provided for this at least near to the inlet end of the broader tubular structure. As in accordance with the method of said patent the speed of travel in the wider tube is also controlled by the inclination of the wider tube, for the fibre being less dense than the liquid, tends to slide up the tube. Thus, the time of treatment of the fibre which is the time to traverse the narrower and Wider tubes, depends on the above factors controlling the speed of travel and also on the length of the wider tube or more accurately on the length of the column of i folded fibre allowed to accumulate in the wider tube before withdrawal. As in accordance with the method of said patent for a tow of given size and rate of delivery the speed of liquid in the narrower tube i. e. the head is adjusted to be somewhat greater than the tow speed. The bore size of the narrower tube is a matter of convenience. The size of the Wider tube is determined by the required time of treatment. It

. V U is possible to vary this time within very wide limits in the same apparatus, as the fibre may be withdrawn through both tubes with very little accumulation-in a fraction of a minute or may be allowed to accumulate in a long column the length of which is determined by the length of the longer tube so that the time of passage may take many minutes.

Care has to be taken that the withdrawal of the tow from the treating liquid is in no way adversely afiected by the treating liquid flowing out of the tubular structure of wider width and for this purpose it is desirable to provide said structure at the exit end with a perforated weir or an equivalent acting device.

Preferably the upper surface of said wider tubular structure is inclined at an angle lying between 5 and 30 to the horizontal.

The tubular structure portion having the narrow bore inlet is preferably of progressively increasing width, appreaching orequal to the width of the tubular strucwithout giving rise to local regions of high speed flow.

ture portion of wider width, in order to prevent ex- 1 cessive turbulence of the liquid flow and possible en tanglement of the filaments forming the tow as it tends to rise in the treating liquid on entering the tubular structure of wider width.

Among the advantages of the present invention over the invention of British Patent No. 642,359 are that the method and apparatus of the present invention permit an upwardly sloping tube of standard length and width to be more easily used for the treatment of large and small tows and for the time of treatment in the i upwardly sloping tube to be more easily varied within reasonably wide limits.

The invention is illustrated by the following ple in which parts are parts by weight except examwhere otherwise stated and with reference to the diagrammatic drawing accompanying the specification which is a front elevation of apparatus suitable for carrying out the method of the invention.

Example A matured caustic soda solution of groundnut glob- 'ulin prepared from a solution containing 20 parts groundnut globulin, 1.25 parts sodium hydroxide, 1.0 part of sodium sulphite and 77.75 parts water is extruded into a coagulating bath containing 200 g./l. so-

'dium sulphate and 20 g./l. sulphuric acid. The resultting bath containing 30 g./l. sodium sulphate, 300 g./'l.

sodium chloride, not more than 3 g./l. sulphuric acid, and 5 g./l. of formaldehyde, at 65 C. From this bath the tow 1 is removed by a godet 2 of peripheral speed 26 metres per minute and passes on to a godet 3 of peripheral speed 29 metres per minute, and then vertically downwards into the constant level feed cone 4, where it is picked up by the hardening liquid which enters the feed cone through a pipe 5 and is then carried through the tube 6 and'the glass cone 7 into the inclined tube 8. The tube 6 is of inch diameter and the glass cone 7 is 4 inches in diameter at the open end. The composition of the hardening liquid is ill g./l. sodium chloride, 405 g./l.' sodium sulphate,.l3 g./l. formaldehyde and 303 g./l. sulphuric acid, and it enters'the tube 8 at 96 C. and overflows at 88 C. Aportion of the hardening liquid'is bled off through the pipe 9. The speed of liquid flow through tube 6 is controlled by the difference in levels of the liquid at the inlet cone 4 and the overflow at the exit end of the tube 8, which in this case is 4 inches, as well as The speed of the tow at feed cone 4 is 29 metres per minute. On entering the inclined tube 8 through the funne 7 the tow forms a loose column about 4 feet long against the upper surface of the tube 8 and the loose column of tow is gently agitated by means of a stream of air bubbles 12 from the bubbler unit 13 which fed with compressed air through the pipe 14. The

air bubbles 12 pass up the tube 8 at the rate of two per second but this rate may be altered as required by operating the valve 15. The loose column of tow about 4 feet long fills roughly about /4 of the cross sectional area and is then removed at the exit. end by a godet application Serial No. 94,866, filed May 23, 1949.

What I claim is:

1. In a method of treating in a non-tensioned condition a continuous tow of filaments with a treating liquid having a specific gravity greater than the specific gravity of the tow comprising subjecting said tow to a rapidly moving current of said treating liquid in an elongated downwardly directed narrow confined zone, said tow being carried by the treating liquid which flows concurrently therewith into the lower end of an upwardly inclined elongated confined zone having a cross-sectional area substantially greater than the cross-sectional area of said narrow zone to thereby reduce the linear velocity of said treating liquid to insure an absence of turbulence in the major portion of said upwardly inclined zone and cause the tow to fold irregularly and form a loose column of fiber which moves slowly up saidupwardly inclined zone against the confining upper surface thereof, the point of exit of said treating liquid from said upwardly inclined :Jne being below the point where said treating liquid enters said narrow zone to thereby permit fiow of said treating liquid down said narrow zone and through said upwardly inclined zone, and withdrawing the thus treated tow at the upper end of said second confined zone, the improvement which comprises controlling the velocity of said treating liquid in said upwardly inclined zone by withdrawing a portion or" said treating liquid from said upwardly inclined zone near the inlet end thereof.

2. In a method as recited inv claim 1, wherein the liquid and tow of filaments in said upwardly inclined zone are agitated.

3. A method as recited in claim 2 in which saidagitation is effected by introducing a stream of bubbles into said upwardly inclined zone near the inlet end thereof.

4. Apparatus for treating in a non-tensioned condition a continuous tow of filaments with a treating liquid having a specific gravity greater than the specific gravity of said tow comprising a first downwardly directed elongated narrow tubular member, means for continuously supplying treating liquid to an upper portion of said first tubular member, a second upwardly inclined elongated tubular member of substantially greater cross-sectional area than the narrowest part of said first tubular member, the lower end or" said first tubular member communicating with the lower end of said upwardly inclined tubular member, said second tubular member having an outlet for liquid on the lower surface thereof, said outlet being a substantial distance above the lowest point on the upper inner surface of said second-tubular, member and a sub: stantial distance below the upper portion of said first tubular member, means to withdraw liquid from said second tubular member positioned near the inlet end of said second tubular member and means to supply compressed gas to the inlet end of said second tubular member.

5. Apparatus as recited in claim 4 in which said means to supply compressed gas is designed to intermittently provide relatively large air bubbles in the treating liquid.

References Cited in the file of this patent UNITED STATES PATENTS 6 Cole Feb. 19, 1929 Walton Aug. 9, 1932 Lowen Aug. 16, 1932 Dreyfus Sept. 22, 1936 Carter May 31, 1938 Nai Sept. 27, 1938 Von-Recklinghausen et a1. Mar. 7, 1939 Wormel Aug. 21, 1945 FOREIGN PATENTS Great Britain of 1889 Great Britain Aug. 30, 1950

Claims

1. IN A METHOD OF TREATING IN A NON-TENSIONED CONDITION A CONTINUOUS TOW OF FILAMENTS WITH A TREATING LIQUID HAVING A SPECIFIC GRAVITY GREATER THAN THE SPECIFIC GRAVITY OF THE TOW COMPRISING SUBJECTING SAID TOW TO A RAPIDLY MOVING CURRENT OF SAID TREATING LIQUID IN AN ELONGATED DOWNWARDLY DIRECTED NARROW CONFINED ZONE, SAID TOW BEING CARRIED BY THE TREATING LIQUID WHICH FLOWS CONCURRENTLY THEREWITH INTO THE LOWER END OF AN UPWARDLY INCLINED ELONGATED CONFINED ZONE HAVING A CROSS-SECTIONAL AREA SUBSTANTIALLY GREATER THAN THE CROSS-SECTION ARE OF SAID NARROW ZONE TO THEREBY REDUCE THE LINEAR VELOCITY OF SAID TREATING LIQUID TO INSURE AN ABSENCE OF TURBULENCE IN THE MAJOR PORTION OF SAID UPWARDLY INCLINED ZONE AND CAUSE THE TOW TO FOLD IRREGULARLY AND FORM A LOOSE COLUMN OF FIBER WHICH MOVES SLOWLY UP SAID UPWARDLY INCLINED ZONE AGAINST THE CONFINING UPPER SURFACE THEREOF, THE POINT OF EXIT OF SAID TREATING LIQUID FROM SAID UPWARDLY INCLINED ZONE BEING BELOW THE POINT WHERE SAID TREATING LIQUID ENTERS SAID NARROW ZONE TO THEREBY PERMIT FLOW OF SAID TREATING LIQUID DOWN SAID NARROW ZONE AND THROUGH SAID UPWARDLY INCLINED ZONE, AND WITHDRAWING THE THUS TREATED TOW AT THE UPPER END OF SAID SECOND CONFINED ZONE, THE IMPROVEMENT WHICH COMPRISES CONTROLLING THE VELOCITY OF SAID TREATING LIQUID IN SAID UPWARDLY INCLINED ZONE BY WITHDRAWING A PORTION OF SAID TREATING LIQUID FROM SAID UPWARDLY INCLINED ZONE NEAR THE INLET END THEREOF.

4. APPARATUS FOR TREATING IN A NON-TENSIONED CONDITION A CONTINUOUS TWO OF FILAMENTS WITH A TREATING LIQUID HAVING A SPECIFIC GRAVITY GREATER THAN THE SEPECIFIC GRAVITY OF SAID TOW COMPRISING A FIRST DOWNWARDLY DIRECTED ELONGATED NARROW TUBULAR MEMBER, MEANS FOR CONTINUOUSLY SUPPLYING TREATING LIQUID TO AN UPPER PORTION OF SAID FIRST TUBULAR MEMBER, A SECOND UPWARDLY INCLINED ELONGATED TUBULAR MEMBER OF SUBSTANTIALLY GREATER CROSS-SECTION AREA THAN THE NARROWEST PART OF SAID FIRST TUBULAR MEMBER, THE LOWER END OF SAID FIRST TUBULAR MEMBER COMMUNICATING WITH THE LOWER END OF SAID UPWARDLY INCLINED TUBULAR MEMBER, SAID SECOND TUBULAR MEMBER HAVING AN OUTLET FOR LIQUID ON LOWER SURFACE THEREOF, SAID OUTLET BEING A SUBSTANTIAL DISTANCE ABOVE THE LOWEST POINT ON THE UPPER INNER SURFACE OF SAID SECOND TUBULAR MEMBER AND A SUBSTANTIAL DISTANCE BELOW THE UPPER PORTION OF SAID FIRST TUBULAR MEMBER, MEANS TO WITHDRAW LIQUID FROM SAID SECOND TUBULAR MEMBER POSITIONED NEAR THE INLET END OF SAID SECOND TUBULAR MEMBER AND MEANS TO SUPPLY COMPRESSED GAS TO THE INLET END OF SAID SECOND TUBULAR MEMEBER.