US2844019A

US2844019A - Apparatus for the aftertreatment of endless cables or tows of artificial filaments

Info

Publication number: US2844019A
Application number: US518874A
Authority: US
Inventors: Schurmann Max-Otto; Haimerl Hans
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1954-07-03
Filing date: 1955-06-29
Publication date: 1958-07-22
Anticipated expiration: 1975-07-22

Description

MAX-OTTO SCHURMANN ETAL 2,844,019 APPARATUS FOR THE AFTERTREATMENT OF ENDLESS CABLES 0R 'rows OF ARTIFICAL FILAMENTS Filed June 29, 1955 July 22, 1958 V 4 Q IIYYENTORS MAX UTTU SCHURMANN HANS HAIME'RL BY: if

ATTOR EYS United States Patent APPARATUS FOR THE AFTERTREATIVIENT OF ENDLESS CABLES 0R TOWS 0F ARTIFICIAL FILANIENTS Max-Otto Schurrnann and Hans Haimerl, Dormagen,

Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany Application June 29, 1955, Serial No. 518,874 Claims priority, application Germany July 3, 1954 5 Claims. (Cl. 68-205) endless screen on which the tow or cable to be aftertreated is laid with a slight lag, and above which are located sprinkler-like devices for supplying the treatment liquids.

This screen has certain disadvantages. It is subjected to wear, particularly at high speeds, and it has a tendency to move laterally on the feeding rollers.

It is anobject of the present invention to provide an improved apparatus for the aftertreatment of endless cables or tows of artificial fiilaments.

More specific objects will become apparent from the following description.

In accordance with the invention it has now been found that a tow or cable consisting of artificial filaments can be continuously aftertreated with a liquid, for instance dilute sulfuric acid, by means of an apparatus comprising a set of rollers, a trough having a base which is provided with openings, a series of sprayshaving a plurality of holes disposed at a distance of from about 5 to about 15 centimeters from said trough, said holes each having a diameter of from about 0.3 to about 0.8 millimeters, a pipeline connected with a pump capable of producing a pressure of from 0.3 to 1.5 atmospheres above the atmospheric pressure in said sprays and a tray disposed underneath said trough to collect the liquid passing through said openings of said trough.

According to the invention the treating liquid is applied to the tow vertically with high speed in fine jets, the tow or cable itself being kept under as small a tension as possible.

Preferably the tow or cable is laid on the horizontal trough and the treating liquid is applied thereto through nozzles or sprays disposed at a small distance thereover. The diameter and speed of the liquid jets must be kept within predetermined limits; jets which are too coarse and strong lead to an undesirable displacement of the fine holes of the nozzles and slow jets fail to produce the optimum effect. The number of holes and their distance from each other should be so selected that the tow or cable is not covered by any substantial amount of liquid. The distance of the sprays of the material to be treated is of importance since it has an influence on the speed of the jets. In selecting the speed and strength of the jets (the first of which is substantially dependent upon the pressure of the liquid in the spray), the thickness of the tow or cable and also that of the individual filaments must be taken into consideration. Thick tows or cables require a more intense treatment than thin ones.

With a thickness of the tow of from about 30,000 to about 100,000 deniers and an individual denier of 2 to 6, a diameter of the holes of 0.3 to 0.8, preferably 0.5 millimeters, a pressure of the aqueous liquid of between about 0.3 to 1.5, preferably 0.5, atmospheres above normal and a distance of the sprays from the tow of from 5 to 15 centimeters, preferably 10 centimeters, has proved effective. The number of holes amounts to about per square decimeter.

As a support, the base of a trough having the greatest possible permeability is employed in order to enable the washing liquid to run unhindered therethrough.

The invention will now be described with reference to the accompanying diagrammatic drawing which illustrates an apparatus adapted to aftertreat endless cables or tows of artificial filaments, and in which 7 Fig. 1 is a cross-sectional view of the new apparatus;

Fig. 2 is a plan view of the new apparatus showing a trough with openings.

A set of rollers 1 is disposed at the entrance side of the apparatus. A trough 2 with openings 3 in its bottom plate is arranged beneath a plurality of sprays or nozzles 4, which are connected with the pump 5 by the pipe ending in tube 7. Beneath the trough there is arranged a tray 8 which collects the liquid coming from the sprays 4 and in which this liquid is mixed with fresh treating liquids from tap 9.

In operating the apparatus, the tow t (or cable) is introduced by means of the set of rollers 1. Thus the tow or cable is drawn on the trough (in the direction of the arrow). The sprays are then operated by starting the motor of pump 5 whereupon the jets of liquid from the sprays 4 are directed against the tow. The liquid passes through the openings 3 of the trough 2 and is collected in the tray 8. It is again concentrated from tap 9.

As shown in Figure 2, the openings 3 in the trough 2 are preferably in the form of slots. The openings are provided transversely of the longitudinal direction of the trough. With this method of construction it has also been found that it is desirable for the sprays 4 (see Figure 1) not to be disposed facing the slots 3, but facing the closed parts of the trough base, as shown in Figure 1.

This arrangement avoids the danger of the tow or cable being forced into the slots by the pressure of the washing liquid. Moreover, layers of liquid are formed on the closed parts of the trough base, the said layers supporting the tow or cable to be washed and facilitating the sliding motion thereof on the support.

Despite the slight tension to which the tow or cable is exposed by being drawn over the bottom of the trough 2, it has been found that the advantages of the method according to the said copending application Ser. No. 474,763 are maintained, particularly a greatly accelerated washing. On account of the film of liquid which is formed on the trough, the friction of the tow or cable is reduced to such a degree that the tension is only slight.

If a number of tows or cables are treated in juxtaposition, it is desirable for thread guides 10 to be arranged at certain intervals in the trough, these guides preventing the bands from converging towards one another. The thread guides can consist of corrugated bars or flat rods fitted with spacing pins. They are laid on or fixed to the trough. Despite the temporary lifting of the tow or cable from the base, there is no reduction in the effect of the liquid bath.

Apart from the saving of time, the apparatus of the invention has the advantage of requiring considerably less room and providing for a more efficient use of the chemicals employed. The invention replaces washing by dilution by washing by displacement. The invention further saves the complicated mechanism which was necessary hitherto in order to keep up a slight tension when tows or cables are washed in long containers. The apparatus is well adapted for hardening freshly spun tows from regenerated cellulose filaments which are apt to adhere to each other. It is especially useful in removing copper from tows or cables freshly spun from cuprammonia cellulose solutions.

The acidifying of the blue fiber with dilute sulfuric acid is one of the most complicated steps in cuprammonia fiber production since the fiber here passes through a state in which it has a maximum tendency to stick. While according to hitherto known methods it was diflicult to obtain a product free from cohering sections, the present process yields a product which is entirely free of cohesion.- The time required for acidifying is about of that required according to previously known methods. This favorable behavior as regards lack of tendency for sticking makes it possible to reintroduce a higher percentage of used precipitating liquid containing ammonia and copper into the process, which renders the process more economical as regards consumption of chemicals. The preclpitating liquid which is reintroduced into the process may be wholly or partly freed of copper by leading it I over a cation exchange resin. The process further allows a reduction of the temperature of the spinning bath, a fact which leads to economy in steam consumption. The further washing of the tow or cable after the removal of the copper may be further accelerated by applying the principles of the invention.

The final washing may be carried out in the same step on the trough or after squeezing out the liquid on a separate trough. The drying of the tow or cable may be effected by applying thereto a vertical stream of heated air of high speed. The advantages of this combined method allow the tow or cable to be continuously processed to the final stages on a very short length of apparatus. A further advantage consists in the complete lack of displacement of individual filaments which would lead to difficulties in the continuous tearing or cutting of the tow or cable into staple. Furthermore it is possible to use the shrinking during acidification and drying to obtain a structural crimp.

We claim:

1. Apparatus for the contacting of tows of artificial filaments with liquid which comprises a substantially horizontally extending trough defining a substantially solid bottom support surface, a multiple number of spaced-apart transverse slots defined through the bottom surface of said trough, means defining a multiple number of spray heads positioned'above said trough for directing the major portion of liquid therethrough onto the solid portion of said trough between said slots, means for passing a tow of artificial filaments substantially coaxially along the bottom surface of said trough and means for passing a liquid to said spray heads.

2. Apparatus according to claim 1 including a collecting vessel positioned below said trough for collecting liquid passing through said slots.

3. Apparatus according to claim 2 in which said means for passing liquid to said spray heads includes pumping means and conduit means for pumping liquid from said vessel to said spray heads.

4. Apparatus according to claim 1 in which said trough bottom is provided with thread guides.

5. Apparatus for the contacting of tows of artificial filaments with liquid which comprises a substantially horizontally extending trough defining a substantially solid bottom support surface, a multiple number of spaced-apart drain openings defined through the bottom of said troughleaving a major portion of trough bottom for the passage of a tow of artificial filaments thereover, means defining a multiple number of spray heads positioned above said trough for directing the major portion of liquid therethrough onto the solid portion of said trough between said openings, means for passing a tow of artificial filarnents substantially coaxially along the bottom surface of said trough and means for passing a liquid to said spray heads. 7

References Cited in the file of this patent UNITED STATES PATENTS 338,096 Meikle Mar. '16, 1886 813,078 Bernhardt "Feb. 20, 1906 846,944 Pichard Mar. 12, 1907 1,989,562 Smith Jan. 29, 1935 2,308,511 Hilliard Jan. 19, 1943 2,351,729 Whitehead June. 20, 1944 FOREIGN PATENTS 298,837 Switzerland Aug. 2, 1954